Cellular senescence in ageing: from mechanisms to therapeutic opportunities

In the paper

“Nuclear DNA damage is often reported as a commonly underlying cause of senescence, mainly in the form of DNA double-strand breaks (DSBs)20 that activate the DNA damage response (DDR) pathway”

What the sources say

• Partly supported

  The Introduction describes senescence as a response that arrests damaged cells, and the Results identify γH2AX and p53BP1 foci among senescence markers. Our copy does not say that nuclear DNA damage is commonly the underlying cause of senescence, that it is mainly double-strand breaks, or that those breaks activate the DNA damage response pathway (searched: double-strand breaks, DDR, γH2AX). (LLM, conf=0.84)

  cites [20] Ovadya, Y. et al. Impaired immune surveillance accelerates accumulation of senescent cells and aging. Nat. Commun. 9, 5435 (2018). sourceExperimental — accuracy not yet measured

In the paper

“p16, an inhibitor of CDK4 and CDK6, is also key in several types of senescence26; p21 is activated early on senescence entry and p16 is activated later, probably to maintain the senescence phenotype27”

What the sources say

• Partly supported

  The Introduction links p21 to establishing senescence, and the Discussion says p16 helps maintain the arrest by preventing its reversal. But the paper does not establish that p21 is activated early and p16 only later; it reports p16 expression even in pre-senescent WI-38 cells. Page numbers are unavailable in our copy. (LLM, conf=0.82)

  cites [26] Beausejour, C. M. et al. Reversal of human cellular senescence: roles of the p53 and p16 pathways. EMBO J. 22, 4212–4222 (2003). sourceExperimental — accuracy not yet measured
• Supported

  The Abstract says that p21-mediated arrest in senescent fibroblasts occurs before p16 accumulation and proposes that p16 helps maintain the arrest. The Discussion likewise describes p16 accumulation after arrest in human diploid fibroblasts. Citation 27 is attached to this timing-and-maintenance claim, rather than the preceding claim about p16 in several types of senescence. (LLM, conf=0.91)

  cites [27] Dulic, V., Beney, G. E., Frebourg, G., Drullinger, L. F. & Stein, G. H. Uncoupling between phenotypic senescence and cell cycle arrest in aging p21-deficient fibroblasts. Mol. Cell. Biol. 20, 6741–6754 (2000). source

In the paper

“These foci mark individual sites of DNA damage and contribute to checkpoint enforcement and cell cycle arrest, until damage has been repaired”

What the sources say

• Partly supported

  In “DNA-damage signaling and cell-cycle checkpoints” (page unavailable), the paper describes DDR factors recruited at double-strand-break sites and signaling that slows or arrests the cell cycle to allow repair. It also says normal cell functioning resumes after effective repair. Our copy does not establish that the foci themselves mark individual damage sites or enforce the checkpoint. (LLM, conf=0.83)

  cites [21] Jackson, S. P. & Bartek, J. The DNA-damage response in human biology and disease. Nature 461, 1071–1078 (2009). sourceExperimental — accuracy not yet measured

In the paper

“During replicative senescence, late-replicating, gene-poor regions display widespread DNA hypomethylation, whereas focal hypermethylation is seen at tumour suppressor genes”

What the sources say

• Supported

  The Results section on late-replicating lamin-associated domains reports that hypomethylation in senescence occurs preferentially in gene-poor, late-replicating regions. The Results section on methylation changes resembling cancer reports small increases in methylation at CpG islands of genes including SFRP2 and IRAK3; the Discussion identifies these as tumour suppressor genes. The paper describes these gains as low-level, not necessarily sufficient to silence the genes. (LLM, conf=0.91)

  cites [64] Cruickshanks, H. A. et al. Senescent cells harbour features of the cancer epigenome. Nat. Cell Biol. 15, 1495–1506 (2013). source

In the paper

“SASP composition varies depending on the cell type and the nature of the initial stimulus, with the oncogenic trigger greatly amplifying protein secretion compared with replicative or irradiation-induced senescence75”

What the sources say

• Supported

  The Discussion describes qualitative and quantitative SASP differences among cell types. The Results (Figure 5C–E) report that oncogenic RAS caused substantially higher secretion of multiple proteins than replicative or irradiation-induced senescence, as well as secretion of proteins not elevated under those other conditions. Page numbers are not provided in our copy. (LLM, conf=0.93)

  cites [75] Coppe, J. P. et al. Senescence-associated secretory phenotypes reveal cell-nonautonomous functions of oncogenic RAS and the p53 tumor suppressor. PLoS Biol. 6, 2853–2868 (2008). source

In the paper

“cells with OIS display only limited changes in methylation patterns compared with cells that have bypassed OIS, indicating that tumour-associated methy-lome changes may arise stochastically and independently of the senescence state65”

What the sources say

• Supported

  The Results section, “Oncogene induced senescence has minimal DNA methylation changes” (page not supplied), reports very minimal methylation changes after OIS, unlike early transformation. The Discussion (page not supplied) says transformation-associated methylation changes evolve stochastically and independently of OIS or a replicative-senescence intermediate. (LLM, conf=0.93)

  cites [65] Xie, W. et al. DNA methylation patterns separate senescence from transformation potential and indicate cancer risk. Cancer Cell 33, 309–321 e305 (2018). source

In the paper

“unlike oncogenic RAS or BRAF, activation of the PI3K–AKT pathway promotes p53-dependent senescence often in the absence of detectable hyperproliferation and strong DNA damage accumulation42,43, suggesting distinct underlying mechanisms”

What the sources say

• Partly supported

  The Introduction and Results report that PI3K–AKT activation induces p53-dependent senescence without an initial hyperproliferative phase or detectable DNA-damage markers, in contrast to H-RASV12. The paper supports the proposed mechanistic distinction from RAS, but our copy does not establish the comparison with oncogenic BRAF. (LLM, conf=0.88)

  cites [42] Astle, M. V. et al. AKT induces senescence in human cells via mTORC1 and p53 in the absence of DNA damage: implications for targeting mTOR during malignancy. Oncogene 31, 1949–1962 (2012). sourceExperimental — accuracy not yet measured
• Supported

  The Introduction states that chronic PI3K/AKT/mTORC1 activation triggers AKT-induced senescence and that, unlike oncogene-induced senescence, it lacks a hyperproliferative burst and DNA damage and relies on p53. The Discussion describes AIS as p53-dependent and DNA-damage-independent and distinguishes its mechanism from BRAF-induced senescence. Page numbers are not provided in our copy. (LLM, conf=0.94)

  cites [43] Chan, K. T. et al. A functional genetic screen defines the AKT-induced senescence signaling network. Cell Death Differ. 27, 725–741 (2020). source

In the paper

“Increased oxidative stress in senescent cells has been linked to the accumulation of dysfunctional mitochondria. Indeed, senescent cells are characterized by changes in mitochondrial mass, membrane potential and mitochondrial morphology46”

What the sources say

• Supported

  The passage labeled “Senolytic therapies” (page not provided) describes greater mitochondrial mass in senescent cells alongside reduced function, lower membrane potential, increased ROS production, and altered morphology. The “Mitochondrial ROS drives senescence” passage also links senescence with elevated mitochondrial ROS and weakened antioxidant defenses. (LLM, conf=0.92)

  cites [46] Chapman, J., Fielder, E. & Passos, J. F. Mitochondrial dysfunction and cell senescence: deciphering a complex relationship. FEBS Lett. 593, 1566–1579 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Telomeres are hypersensitive to DNA replication stress, including that induced by oncogenes and accumulation of oncogene-induced telomeric dysfunction, and a DDR has been observed in hyperplastic cancer lesions in humans44”

What the sources say

• Supported

  The Results section on oncogenic H-RasV12 reports that telomeres were preferential sites of oncogene-induced DNA replication stress; the Results section on replication stress also reports telomere dysfunction after drug-induced stress. In the Results section on breast- and colon-cancer precursor lesions, the authors observed prominent DDR-marker foci in hyperplastic regions of human lesions. The indexed passages provide no page numbers. (LLM, conf=0.94)

  cites [44] Suram, A. et al. Oncogene-induced telomere dysfunction enforces cellular senescence in human cancer precursor lesions. EMBO J. 31, 2839–2851 (2012). source

In the paper

“Low doses of HDAC inhibitors have been reported to reduce CCFs and suppress the senescence-associated secretory phenotype (SASP)63”

What the sources say

• Supported

  In the Results section on HDAC inhibitors (page not supplied), the authors report that low-dose TSA significantly decreased cytoplasmic chromatin fragments and reduced expression of SASP genes in senescent cells. The Discussion explicitly describes anti-SASP activity at low doses. (LLM, conf=0.94)

  cites [63] Vizioli, M. G. et al. Mitochondria-to-nucleus retrograde signaling drives formation of cytoplasmic chromatin and inflammation in senescence. Genes Dev. 34, 428–445 (2020). source

In the paper

“treatment with histone deacetylase (HDAC) inhibitors, which induce chromatin relaxation, boosts DDR signalling with consequent cell death by apoptosis. This treatment is probably the first reported example of a successful senolytic approach52, which was later supported by the reported senolytic activity of the HDAC inhibitor panobinostat55”

What the sources say

• Partly supported

  The Results section ('Oncogene-induced heterochromatin restrains DDR signalling'; page unavailable) reports that HDAC inhibitors perturb heterochromatin, increase DDR signalling and induce apoptosis in oncogene-expressing cells. But the cells described as selectively eliminated were proliferating, and the paper does not establish this as a first successful senolytic approach that eliminates senescent cells. The later panobinostat finding is attached to a different citation in the citing sentence. (LLM, conf=0.88)

  cites [52] Di Micco, R. et al. Interplay between oncogene-induced DNA damage response and heterochromatin in senescence and cancer. Nat. Cell Biol. 13, 292–302 (2011). sourceExperimental — accuracy not yet measured
• Supported

  Citation 55 is attached to the later claim about panobinostat’s senolytic activity, not the earlier account of chromatin relaxation and DDR signalling. The Results section, “Pano has Senolytic Activity in CIS,” reports substantial loss of chemotherapy-induced senescent cells after panobinostat treatment, with markers confirming cell death. (LLM, conf=0.94)

  cites [55] Samaraweera, L., Adomako, A., Rodriguez-Gabin, A. & McDaid, H. M. A novel indication for panobinostat as a senolytic drug in NSCLC and HNSCC. Sci. Rep. 7, 1900 (2017). source

In the paper

“SAHF are not universal markers of senescence; they are most robustly observed upon oncogene activation and form in a DNA replication- and ATR-dependent manner52”

What the sources say

• Supported

  In Results, ‘SAHF are preferentially associated with oncogene-induced DNA replication stress,’ BJ fibroblasts formed SAHF after oncogenic Ras expression but not after the other senescence-inducing treatments tested. The same section reports that oncogene-induced SAHF formation depends on DNA replication and ATR. (LLM, conf=0.94)

  cites [52] Di Micco, R. et al. Interplay between oncogene-induced DNA damage response and heterochromatin in senescence and cancer. Nat. Cell Biol. 13, 292–302 (2011). source

In the paper

“One or a few DDR signalling telomeres are sufficient to trigger replicative cellular senescence33, and forced expression of telomerase prevents cellular senescence and promotes unlimited cell proliferation34”

What the sources say

• Partly supported

  The Discussion (page unavailable) says individual critically short telomeres trigger cellular responses and are sufficient to produce phenotypes in late-generation telomerase-deficient mice, including cell-cycle arrest. It does not establish that one or a few DDR-signalling telomeres trigger replicative senescence specifically. The separate claim about forced telomerase expression carries citation 34, so it is not assessed against this source. (LLM, conf=0.85)

  cites [33] Hemann, M. T., Strong, M. A., Hao, L. Y. & Greider, C. W. The shortest telomere, not average telomere length, is critical for cell viability and chromosome stability. Cell 107, 67–77 (2001). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [34] Bodnar, A. G. et al. Extension of life-span by introduction of telomerase into normal human cells. Science 279, 349–352 (1998). source

In the paper

“These changes in chromatin structure were not linked to the selective removal of repressive histone marks, but were associated with changes in nuclear structural proteins, including breakdown of the nuclear lamina57”

What the sources say

• Partly supported

  The Results section (page unavailable) reports that satellite distension occurs without changes in the measured repressive histone marks and is associated with depleted LaminB1 staining. The Discussion proposes that changes in nuclear structural proteins may contribute to the unfolding. The paper does not show breakdown of the nuclear lamina as a whole; that part of the claim overstates its evidence. (LLM, conf=0.83)

  cites [57] Swanson, E. C., Manning, B., Zhang, H. & Lawrence, J. B. Higher-order unfolding of satellite heterochromatin is a consistent and early event in cell senescence. J. Cell Biol. 203, 929–942 (2013). sourceExperimental — accuracy not yet measured

In the paper

“HMGB2 directly binds and specifically regulates SASP gene expression in oncogene-induced senescent cells, and its depletion diminishes SASP without affecting the senescence growth arrest108.”

What the sources say

• Supported

  In Results and discussion, “HMGB2 preferentially binds to SASP gene loci in senescent cells” reports HMGB2 binding at SASP loci in oncogenic RAS-induced senescent IMR90 cells (Fig. 2). “Loss of HMGB2 blunts SASP gene expression” reports that HMGB2 knockdown reduced SASP gene expression without altering senescence-associated cell-cycle arrest (Fig. 3). Page numbers are not provided in the supplied copy. (LLM, conf=0.94)

  cites [108] Aird, K. M. et al. HMGB2 orchestrates the chromatin landscape of senescence-associated secretory phenotype gene loci. J. Cell Biol. 215, 325–334 (2016). source

In the paper

“ATM, NBS1 and CHK2 prime SASP genes for activation, as depletion of these DDR upstream regulators dampens cytokine production in response to genotoxic stress86”

What the sources say

• Partly supported

  The passage labeled Abstract (page unavailable; Figs. 4–5) reports that depleting ATM, NBS1 or CHK2 prevented the irradiation-induced increase in IL-6 secretion, and that ATM depletion reduced secretion of several SASP factors. It supports their role in initiating the cytokine response, but does not establish that they prime SASP genes for activation. (LLM, conf=0.85)

  cites [86] Rodier, F. et al. Persistent DNA damage signalling triggers senescence-associated inflammatory cytokine secretion. Nat. Cell Biol. 11, 973–979 (2009). This study demonstrates that persistent DDR activation controls SASP induction in senescent cells. sourceExperimental — accuracy not yet measured

In the paper

“p16 induction can arrest the proliferation of normal cells and drive cellular senescence but is not sufficient to induce a complete SASP85”

What the sources say

• Supported

  The Results (p. 3) report that ectopic p16INK4a expression induced stable growth arrest and other signs of senescence in normal human fibroblasts without inducing a SASP. The paper also states on p. 2 that ectopic p16INK4a induced a senescence growth arrest without a concomitant SASP. (LLM, conf=0.94)

  cites [85] Coppe, J. P. et al. Tumor suppressor and aging biomarker p16(INK4a) induces cellular senescence without the associated inflammatory secretory phenotype. J. Biol. Chem. 286, 36396–36403 (2011). source

In the paper

“NOTCH1 levels increase early on, and NOTCH1 activates transforming growth factor-β and its effectors, while keeping under control the proinflammatory arm of the SASP cascade by repressing its positive regulator C/EBPβ.”

What the sources say

• Supported

  The Results section on dynamic NOTCH1 signalling reports that cell-surface NOTCH1 increases during senescence and that NOTCH1 activity rises transiently during the transition. The Results sections on TGF-β signalling and C/EBPβ report induction of TGF-β targets and propose that NOTCH1 suppresses pro-inflammatory cytokines through repression of C/EBPβ-mediated transcription. Page numbers are not provided in our copy. (LLM, conf=0.92)

  cites [94] Hoare, M. et al. NOTCH1 mediates a switch between two distinct secretomes during senescence. Nat. Cell Biol. 18, 979–992 (2016). source

In the paper

“BRD4 contributes to the proper execution of cellular senescence and acts, unexpectedly, as a tumour suppressor.”

What the sources say

• Supported

  The Discussion (‘BRD4 is required for paracrine senescence and immune surveillance’) describes an unexpected role for BRD4 in the tumor-suppressive senescence program. It specifies that BRD4 supports paracrine signaling and immune surveillance, while being dispensable for senescence-associated cell-cycle arrest. (LLM, conf=0.90)

  cites [71] Tasdemir, N. et al. BRD4 connects enhancer remodeling to senescence immune surveillance. Cancer Discov. 6, 612–629 (2016). source

In the paper

“HMGB1 functions mainly as one of the damage-associated molecular patterns, also known as alarmins109, that are released extracellularly to induce SASP-mediated paracrine senescence and alert the immune system110.”

What the sources say

• Partly supported

  Section 4.1 (HMGB1; page unavailable) identifies HMGB1 as a DAMP and says extracellular HMGB1 can mediate inflammatory and immune responses, including senescence-associated inflammation. It does not say HMGB1 induces SASP-mediated paracrine senescence. The section also describes substantial nuclear functions, so it does not establish that HMGB1 acts mainly as an extracellular alarmin. (LLM, conf=0.88)

  cites [109] Huang, J. et al. DAMPs, ageing, and cancer: the ‘DAMP hypothesis’. Ageing Res. Rev. 24, 3–16 (2015). sourceExperimental — accuracy not yet measured
• Partly supported

  The Introduction identifies HMGB1 as an alarmin and DAMP, and the Discussion says senescent cells secrete it and suggests that secretion initiates the SASP. The Introduction says SASP factors affect neighboring cells, but does not establish that HMGB1 induces paracrine senescence. The Discussion says HMGB1 secretion may promote immune removal of senescent cells; it does not establish this as a demonstrated effect or describe HMGB1 as acting mainly outside the cell. (LLM, conf=0.86)

  cites [110] Davalos, A. R. et al. p53-dependent release of alarmin HMGB1 is a central mediator of senescent phenotypes. J. Cell Biol. 201, 613–629 (2013). sourceExperimental — accuracy not yet measured

In the paper

“Indeed, chemical and genetic inactivation of BRD4 blunts the SASP, limits OIS immune-mediated cell clearance and may thus fail to remove damaged cells that are prone to senescence escape71.”

What the sources say

• Supported

  The Results sections on SASP expression and in vivo immune surveillance report that genetic BRD4 inhibition blunts the SASP and impairs clearance of oncogene-expressing senescent cells; pharmacological BET inhibition also impairs clearance. The Discussion section on immune surveillance raises the possibility that sustained BRD4 inhibition could allow rare oncogene-expressing cells to evade senescence. The claim appropriately presents that last outcome as a possibility, not an established result. (LLM, conf=0.91)

  cites [71] Tasdemir, N. et al. BRD4 connects enhancer remodeling to senescence immune surveillance. Cancer Discov. 6, 612–629 (2016). source

In the paper

“NF-κB and the transcription factor CCAAT/enhancer-binding protein-β (C/EBPβ) bind promoters of SASP genes and regulate their activation74,93,94”

What the sources say

• Partly supported

  In the passages headed “C/EBPβ Is a Critical Regulator of IL-6 in OIS” and “IL-8 Plays a Role in OIS” (indexed as Abstract; page unavailable), the paper reports C/EBPβ binding to the IL6 and IL8 promoters and regulating their expression. Searches for NF-κB and NF-kappaB found no passage establishing its promoter binding or regulatory role, so that part of the claim is unsupported by this source. (LLM, conf=0.88)

  cites [74] Kuilman, T. et al. Oncogene-induced senescence relayed by an interleukin-dependent inflammatory network. Cell 133, 1019–1031 (2008). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results report RelA (an NF-κB component) binding the IL-8 and GROγ promoters and show that depleting either RelA or C/EBPβ reduces induction of several senescence-associated chemokines. They identify predicted C/EBPβ promoter-binding sites, but do not report directly observing C/EBPβ binding those promoters during senescence; the evidence also concerns CXCR2 ligands rather than SASP genes generally. (LLM, conf=0.84)

  cites [93] Acosta, J. C. et al. Chemokine signaling via the CXCR2 receptor reinforces senescence. Cell 133, 1006–1018 (2008). sourceExperimental — accuracy not yet measured
• Partly supported

  In Results (“NOTCH1 regulates senescence secretome through repression of C/EBPβ”; page not provided), the paper reports C/EBPβ binding at the IL1A, IL6 and IL8 promoters and links it to cytokine expression. It also says NF-κB cooperatively regulates the SASP, but does not establish that NF-κB binds SASP-gene promoters. (LLM, conf=0.85)

  cites [94] Hoare, M. et al. NOTCH1 mediates a switch between two distinct secretomes during senescence. Nat. Cell Biol. 18, 979–992 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Because GATA4 levels increase following DDR activation and in senescent cells, it was proposed that GATA4 acts as the molecular link between DDR signalling and the subsequent NF-κB activation for full SASP establishment95,96, although GATA4 regulation of the NF-κB pathway happens indirectly through increased expression and secretion of IL-1α, an upstream regulator of NF-κB97”

What the sources say

• Partly supported

  The sections ‘GATA4, a new branch of the senescence regulatory pathway’ and ‘GATA4 regulates NF-κB’ place GATA4 downstream of DDR signalling and upstream of NF-κB in SASP regulation. The latter section identifies IL1A as one mediator, but also identifies TRAF3IP2; it does not specifically show increased IL1A secretion. Page numbers are unavailable in our copy. (LLM, conf=0.85)

  cites [95] Kang, C. et al. The DNA damage response induces inflammation and senescence by inhibiting autophagy of GATA4. Science 349, aaa5612 (2015). sourceExperimental — accuracy not yet measured
• Partly supported

  In Results and Discussion (page not available), the paper proposes that ATM/ATR may regulate GATA4 through USP28 and links GATA4 to SASP activation. It also places NF-κB pathway components in the GATA4 branch, but does not explicitly establish the claimed sequence of GATA4-mediated NF-κB activation. The IL-1α mechanism is attached to a different citation in the citing sentence. (LLM, conf=0.82)

  cites [96] Mazzucco, A. E. et al. Genetic interrogation of replicative senescence uncovers a dual role for USP28 in coordinating the p53 and GATA4 branches of the senescence program. Genes Dev. 31, 1933–1938 (2017). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [97] Orjalo, A. V., Bhaumik, D., Gengler, B. K., Scott, G. K. & Campisi, J. Cell surface-bound IL-1alpha is an upstream regulator of the senescence-associated IL-6/IL-8 cytokine network. Proc. Natl Acad. Sci. USA 106, 17031–17036 (2009). source

In the paper

“Inhibition of p53 has the opposite effect, as it further enhances SASP following a senescence-inducing insult86, which may contribute to the generation of an inflammatory microenvironment that favours senescence escape and malignant transformation”

What the sources say

• Supported

  The passage labelled Abstract reports that p53 inactivation in replicatively senescent HCA2 cells increased secretion of IL-6, a principal SASP factor. The citation is attached to the p53-inhibition clause; the proposed consequences for the inflammatory microenvironment are the citing authors’ subsequent interpretation. (LLM, conf=0.87)

  cites [86] Rodier, F. et al. Persistent DNA damage signalling triggers senescence-associated inflammatory cytokine secretion. Nat. Cell Biol. 11, 973–979 (2009). This study demonstrates that persistent DDR activation controls SASP induction in senescent cells. source

In the paper

“At later stages, in deeply senescent cells, NOTCH1 levels are lower, and the SASP proinflammatory cytokines IL-1, IL-6 and IL-8 are induced94.”

What the sources say

• Partly supported

  In Results, “NOTCH1 signalling is dynamically regulated during senescence” (page unavailable), active NOTCH1 signalling returns near basal levels at full senescence, and IL-6 and IL-8 are primarily upregulated then. But cell-surface NOTCH1 continually increases rather than becoming lower. The paper identifies IL-1 as a proinflammatory SASP component, but the cited passage does not establish that IL-1 is induced specifically at full senescence. (LLM, conf=0.90)

  cites [94] Hoare, M. et al. NOTCH1 mediates a switch between two distinct secretomes during senescence. Nat. Cell Biol. 18, 979–992 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Single-cell transcriptomic analysis of human HSCs revealed a dose-dependent activation of senescence-like programmes in response to DSBs, which were characterized by activation of p53 and the induction of proinflammatory programmes that resulted in reduced clonogenic potential, engraftment capacity and lineage output on transplantation126.”

What the sources say

• Partly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites [126] Schiroli, G. et al. Precise gene editing preserves hematopoietic stem cell function following transient p53-mediated DNA damage response. Cell Stem Cell 24, 551–565 e558 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Treatment with nucleoside reverse-transcriptase inhibitors, which inhibit retrotransposition of transposable elements, limits the senescence-associated detrimental effects of SASP and ameliorates chronic inflammation in aged animals62,119.”

What the sources say

• Supported

  In “Activation of L1 in human and mouse tissues,” the paper reports that the NRTI 3TC reduced the SASP pro-inflammatory state in old mice and opposed macrophage infiltration, a marker of chronic inflammation. The Extended Data description reports a test of 3TC’s effect on L1 retrotransposition, while “Consequences of L1 activation” links NRTI efficacy to inhibition of L1 reverse transcriptase. The evidence is specific to L1 and to 3TC treatment in aged animals. (LLM, conf=0.91)

  cites [62] De Cecco, M. et al. L1 drives IFN in senescent cells and promotes age-associated inflammation. Nature 566, 73–78 (2019). source
• Partly supported

  In Results (‘L1 misexpression and sterile inflammation in aged mice’), d4T treatment significantly reduced type I interferons in several tissues of aged wild-type mice, supporting the inflammation claim. The paper reports only a trend toward lower plasma levels of SASP-associated cytokines, however, so the claim that treatment limits the detrimental effects of SASP is stronger than the reported finding. (LLM, conf=0.86)

  cites [119] Simon, M. et al. LINE1 derepression in aged wild-type and SIRT6-deficient mice drives inflammation. Cell Metab. 29, 871–885 e875 (2019). sourceExperimental — accuracy not yet measured

In the paper

“This distinctively strong induction of type I interferon was found to be partly caused by reactivation of transposable elements and consequent to cGAS–STING activation62.”

What the sources say

• Supported

  In “Activation of L1 and interferon in cellular senescence” (page not provided), the paper reports high IFN-I induction alongside late L1 activation. “Consequences of L1 activation” reports that knocking down cGAS or STING inhibited the IFN-I response, supporting the claimed pathway. The paper identifies L1 cDNA as an important inducer, consistent with the claim that transposable-element reactivation is a partial cause. (LLM, conf=0.92)

  cites [62] De Cecco, M. et al. L1 drives IFN in senescent cells and promotes age-associated inflammation. Nature 566, 73–78 (2019). source

In the paper

“DNA damage, for example induced by ionizing radiation, has been shown to promote differentiation and induce cellular senescence in mouse neural stem cells128.”

What the sources say

• Supported

  The Discussion states that DNA damage in neural stem cells leads to cellular senescence and promotes astrocytic differentiation. The Results describe these effects after X-ray irradiation, and the paper reports irradiation-induced differentiation in a mouse model. Page numbers are not provided in our copy. (LLM, conf=0.94)

  cites [128] Schneider, L. et al. DNA damage in mammalian neural stem cells leads to astrocytic differentiation mediated by BMP2 signaling through JAK-STAT. Stem Cell Rep. 1, 123–138 (2013). source

In the paper

“Markers of DDR signalling, heterochromatin induction and activation of SASP, including the secretion of IL-6 and accumulation of SA-β-gal, were all detected in different types of neurons in ageing mice, and a short period of dietary restriction prevented their accumulation134.”

What the sources say

• Partly supported

  The Results report age-related increases in DDR, heterochromatin-associated mH2A, IL-6 staining, and sen-β-Gal in mouse neurons. They also report that three months of dietary restriction reduced several markers in Purkinje neurons. The paper measures IL-6 staining rather than secretion, and it does not show that dietary restriction prevented all the listed markers from accumulating across the different neuron types. (LLM, conf=0.88)

  cites [134] Jurk, D. et al. Postmitotic neurons develop a p21-dependent senescence-like phenotype driven by a DNA damage response. Aging Cell 11, 996–1004 (2012). sourceExperimental — accuracy not yet measured

In the paper

“The functional capacity of stem cells, but not necessarily their number, declines with age120.”

What the sources say

• Partly supported

  Section 4 (page not provided) reports that several studies found declining reconstituting capacity per hematopoietic stem cell with age, while the stem-cell population increased in B6 mice. This supports the distinction between function and number, but the cited paper’s evidence concerns hematopoietic stem cells, not stem cells generally. (LLM, conf=0.84)

  cites [120] Warren, L. A. & Rossi, D. J. Stem cells and aging in the hematopoietic system. Mech. Ageing Dev. 130, 46–53 (2009). sourceExperimental — accuracy not yet measured

In the paper

“In old mice, osteocytes show markers of telomeric dysfunction and accumulate p16.”

What the sources say

• Partly supported

  The paper reports that p16Ink4a expression in mouse osteocytes increases markedly after about 18 months of age (Abstract; page unavailable). It also measures senescence-associated distention of satellites in osteocytes, but the Online Methods identify these as decondensed or elongated centromeres, not markers of telomeric dysfunction. The telomeric-dysfunction part of the claim is therefore unsupported by our copy. (LLM, conf=0.88)

  cites [139] Farr, J. N. et al. Targeting cellular senescence prevents age-related bone loss in mice. Nat. Med. 23, 1072–1079 (2017). sourceExperimental — accuracy not yet measured

In the paper

“The DNA sensor cGAS and the adaptor protein STING have been reported to be major regulators of the SASP programme across species, presumably by activating NF-κB and the interferon response factor IRF3 (REFS60,112,113).”

What the sources say

• Partly supported

  The supplied Abstract passages (no page specified) report that cGAS–STING is required for the SASP in human cells, that STING mediates a SASP response in mice, and that the pathway activates NF-κB. They distinguish IRF3 as part of the interferon pathway and report that interferon genes are not induced in senescence; they do not support IRF3 activation as a mechanism of the SASP. (LLM, conf=0.88)

  cites [60] Dou, Z. et al. Cytoplasmic chromatin triggers inflammation in senescence and cancer. Nature 550, 402–406 (2017). This study demonstrates that cytoplasmic chromatin in senescent and cancer cells activates the innate immunity through the cGAS–STING pathway. sourceExperimental — accuracy not yet measured
• Partly supported

  The sections on paracrine senescence and diverse senescence triggers report that cGAS–STING regulates SASP components in mouse and human cells. The Introduction identifies NF-κB as a regulator of SASP genes, but our copy does not link cGAS–STING’s effect on the SASP specifically to activation of NF-κB and IRF3; that proposed mechanism remains unsupported by this source. (LLM, conf=0.84)

  cites [112] Gluck, S. et al. Innate immune sensing of cytosolic chromatin fragments through cGAS promotes senescence. Nat. Cell Biol. 19, 1061–1070 (2017). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results report that cGAS is required for induction of most SASP genes by DNA-damaging agents in human and mouse cells. The introduction describes STING activating NF-κB and IRF3, but the paper does not establish that STING regulates the SASP through those factors. Indeed, the Results report that STING loss did not accelerate spontaneous immortalization, suggesting a STING-independent role for cGAS. (LLM, conf=0.87)

  cites [113] Yang, H., Wang, H., Ren, J., Chen, Q. & Chen, Z. J. cGAS is essential for cellular senescence. Proc. Natl Acad. Sci. USA 114, E4612–E4620 (2017). sourceExperimental — accuracy not yet measured

In the paper

“Such phenotypes were exacerbated in telomerase-inactivated mice, while p21 loss reduced many of these markers.”

What the sources say

• Supported

  The Results report increased DNA-damage response, p38MAPK activation, oxidative damage, and IL-6 production in neurons of late-generation telomerase-knockout mice with dysfunctional telomeres. They also report that these markers returned to normal in Purkinje and cortical neurons when p21 was knocked out in those mice. (LLM, conf=0.94)

  cites [134] Jurk, D. et al. Postmitotic neurons develop a p21-dependent senescence-like phenotype driven by a DNA damage response. Aging Cell 11, 996–1004 (2012). source

In the paper

“SASP activation in osteocytes was shown to promote osteoclast activity, thus impairing bone strength. In this context, senolytic drugs reduced bone loss139.”

What the sources say

• Partly supported

  The passages labeled Abstract (no page supplied) report that senescent osteocytes develop the SASP, that senescent-cell conditioned medium promotes osteoclastogenesis, and that senolytic treatment improves bone mass and strength in old mice. They do not establish that osteocyte-derived SASP specifically caused the increased osteoclast activity or impaired bone strength; the conditioned-medium experiment concerns senescent cells generally. (LLM, conf=0.86)

  cites [139] Farr, J. N. et al. Targeting cellular senescence prevents age-related bone loss in mice. Nat. Med. 23, 1072–1079 (2017). sourceExperimental — accuracy not yet measured

In the paper

“it was reported that senescence occurs in a programmed manner and contributes to mammalian embryonic development and tissue patterning, although mainly via induction of p21, p15 and mediators of the SASP rather than through overt DDR signalling131,132.”

What the sources say

• Supported

  The Summary (p. 1) describes embryonic senescence as a programmed mechanism involved in patterning and reports expression of p21, p15, and SASP mediators. The Discussion (pp. 8–9) reiterates those features and says the authors did not detect DNA damage in embryonic senescent cells, supporting the contrast with overt DDR signalling. (LLM, conf=0.90)

  cites [131] Storer, M. et al. Senescence is a developmental mechanism that contributes to embryonic growth and patterning. Cell 155, 1119–1130 (2013). source
• Partly supported

  The Essential Role of p21 section reports programmed senescence during embryonic development, tissue remodeling, dependence on p21, and no detectable DNA-damage signaling. But the Developmentally Programmed Senescence Requires p21 Independently of p53 section explicitly excludes a relevant role for p15; the cited passages do not establish SASP mediators as a main mechanism. (LLM, conf=0.90)

  cites [132] Munoz-Espin, D. et al. Programmed cell senescence during mammalian embryonic development. Cell 155, 1104–1118 (2013). sourceExperimental — accuracy not yet measured

In the paper

“DNA damage and markers of DDR activation have been observed in various stem cell types in different tissues and species, during normal and pathological ageing121,122, suggesting that stem cells are not immune to DNA damage accumulation and DDR activation123.”

What the sources say

• ?Not checked — no full text of the sourcecites [121] Rossi, D. J. et al. Deficiencies in DNA damage repair limit the function of haematopoietic stem cells with age. Nature 447, 725–729 (2007). source
• Supported

  The Discussion states that tissue-specific stem cells accrue DNA damage during aging despite being considered protected populations. The Hematopoietic stem cells section also describes DNA-damage-response markers in aged HSCs, supporting the inference attributed to this citation. Page numbers were not provided in the supplied passages. (LLM, conf=0.91)

  cites [122] McNeely, T., Leone, M., Yanai, H. & Beerman, I. DNA damage in aging, the stem cell perspective. Hum. Genet. https://doi.org/10.1007/s00439-019-02047-z (2019). source
• ?Not checked — no full text of the sourcecites [123] Sperka, T., Wang, J. & Rudolph, K. L. DNA damage checkpoints in stem cells, ageing and cancer. Nat. Rev. Mol. Cell Biol. 13, 579–590 (2012). source

In the paper

“DNA damage led to a loss of expression of stemness genes and a general induction of a transcriptional profile indicative of differentiation into astrocytes. This cell differentiation programme was controlled by ATM and by soluble factors, in particular through BMP2 signalling128.”

What the sources say

• Supported

  The Results section (“DNA Damage Induces Astrocytic Differentiation”; page not available) reports reduced expression of NSC and self-renewal genes and a gene-expression pattern resembling astrocytic differentiation. The Discussion (page not available) states that soluble-factor secretion promotes this differentiation through ATM-dependent BMP2/JAK-STAT signaling. (LLM, conf=0.93)

  cites [128] Schneider, L. et al. DNA damage in mammalian neural stem cells leads to astrocytic differentiation mediated by BMP2 signaling through JAK-STAT. Stem Cell Rep. 1, 123–138 (2013). source

In the paper

“This response is mediated by SASP components and by the direct interaction between immune cells and senescent cells153,156–158.”

What the sources say

• Partly supported

  The Results sections on SASP and macrophage function show that SASP factors affect macrophage targeting of senescent hepatic stellate cells. The co-culture experiments show macrophages eliminating those cells, but do not establish that direct cell-to-cell contact mediates the response. Page numbers are unavailable in our copy. (LLM, conf=0.85)

  cites [153] Lujambio, A. et al. Non-cell-autonomous tumor suppression by p53. Cell 153, 449–460 (2013). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [156] Kang, T. W. et al. Senescence surveillance of pre-malignant hepatocytes limits liver cancer development. Nature 479, 547–551 (2011). source
• Supported

  The Results section, “ERK activity regulates the expression of MICA and ULBP2” (page not available), says the senescent secretome can attract immune cells. The Discussion (page not available) describes cell-surface NKG2D ligands interacting with receptors on NK cells to enable recognition and elimination of senescent cells. (LLM, conf=0.91)

  cites [157] Sagiv, A. et al. NKG2D ligands mediate immunosurveillance of senescent cells. Aging 8, 328–344 (2016). source
• Supported

  The paper says the senescent-cell secretory phenotype attracts immune cells and enables removal of senescent cells (passage [1]). It also reports that contact-dependent protein transfer from senescent cells to NK cells increases their cytotoxicity (passage [3]); the Discussion identifies this as an additional mechanism of immune-mediated self-elimination (passage [6]). (LLM, conf=0.92)

  cites [158] Biran, A. et al. Senescent cells communicate via intercellular protein transfer. Genes Dev. 29, 791–802 (2015). source

In the paper

“SASP from these cells attracts natural killer (NK) cells that eliminate senescent cells from the liver to restore liver homeostasis145.”

What the sources say

• Partly supported

  The Results report that senescent stellate cells upregulate secretory and immune-surveillance genes, and that NK-cell activity promotes their clearance and fibrosis resolution in mice. But the Results describe signals from senescent cells attracting immune cells as a possibility, not an established SASP-driven recruitment mechanism; the Discussion likewise proposes, rather than demonstrates, a return to the liver’s pre-damaged state. Page numbers are unavailable in our copy. (LLM, conf=0.87)

  cites [145] Krizhanovsky, V. et al. Senescence of activated stellate cells limits liver fibrosis. Cell 134, 657–667 (2008). This study demonstrates that immune cell targeting of senescent cells limits dysfunction in the liver. sourceExperimental — accuracy not yet measured

In the paper

“Genome-wide association studies have recently revealed that the INK4/ARF gene locus, encoding p15INK4B, p16 and ARF, key effectors of the senescence growth arrest, is a genomic hotspot for susceptibility to several ageing-associated diseases, including cancer, diabetes and cardiovascular disease167,168, and physical dysfunction in people with advancing age169,170.”

What the sources say

• Supported

  The paper’s Abstract identifies INK4/ARF as a GWAS disease-susceptibility hotspot, names its p15INK4b, p16INK4a and p14ARF transcripts, and links the locus to cancers, type 2 diabetes and atherosclerotic diseases. The citing sentence places separate citations after the claim about physical dysfunction, so that claim is not attributed to this source. (LLM, conf=0.91)

  cites [167] Jeck, W. R., Siebold, A. P. & Sharpless, N. E. Review: a meta-analysis of GWAS and age-associated diseases. Aging Cell 11, 727–731 (2012). source
• ?Not checked — no full text of the sourcecites [168] Melzer, D. Genetic polymorphisms and human aging: association studies deliver. Rejuvenation Res. 11, 523–526 (2008). source
• Partly supported

  The Discussion reports an association between a variant near p16/ARF and less limited physical functioning in people aged 65–80, supporting the physical-dysfunction portion of the citation. However, the Materials and methods describes a targeted screen of 25 SNPs, not a genome-wide association study; the cancer, diabetes and cardiovascular-disease portion is attached to other citations. (LLM, conf=0.87)

  cites [169] Melzer, D. et al. A common variant of the p16(INK4a) genetic region is associated with physical function in older people. Mech. Ageing Dev. 128, 370–377 (2007). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results identify p16INK4a and p15 in the set of genes shared across age-related disease categories, and the Discussion identifies the 9p21 senescence-associated locus as associated with multiple diseases (page numbers unavailable). Our copy does not establish the full p15INK4B–p16–ARF description or link this locus to physical dysfunction with advancing age. (LLM, conf=0.82)

  cites [170] Johnson, S. C., Dong, X., Vijg, J. & Suh, Y. Genetic evidence for common pathways in human age-related diseases. Aging Cell 14, 809–817 (2015). sourceExperimental — accuracy not yet measured

In the paper

“That cellular senescence is causative for frailty and age-associated diseases was demonstrated by transplantation of relatively few senescent cells and observation of tissue dysfunction and shortened lifespan in mice174.”

What the sources say

• Partly supported

  The Results report that transplanting small numbers of senescent cells impaired physical function in mice and reduced survival in older recipients. But the same Results section says disease burden at death was not significantly altered, so the transplantation findings do not establish causation for age-associated diseases generally (page not provided). (LLM, conf=0.88)

  cites [174] Xu, M. et al. Senolytics improve physical function and increase lifespan in old age. Nat. Med. 24, 1246–1256 (2018). This study demonstrates that transplanting senescent cells in young mice causes persistent physical dysfunction that can be alleviated by senolytic drugs. sourceExperimental — accuracy not yet measured

In the paper

“Cellular communication network factor 1 (CCN1; also known as CYR61), an ECM protein that mediates the induction of cellular senescence in the liver, promotes senescence in fibroblasts during cutaneous wound healing, thus limiting skin fibrosis147.”

What the sources say

• Partly supported

  The Introduction and Results identify CCN1 as CYR61 and report that it induces fibroblast senescence during cutaneous wound healing, curbing fibrosis. The paper does not establish that CCN1 mediates senescence in the liver: its Discussion says whether CCN1 is required for senescence in other organs is unknown. Page numbers were not available in our copy. (LLM, conf=0.90)

  cites [147] Jun, J. I. & Lau, L. F. The matricellular protein CCN1 induces fibroblast senescence and restricts fibrosis in cutaneous wound healing. Nat. Cell Biol. 12, 676–685 (2010). sourceExperimental — accuracy not yet measured

In the paper

“Removal of p16-positive cells in both p16-3MR and INK-ATTAC transgenic mice by both genetic methods and senolytics reduced plaque formation and progression, while dampening the SASP175.”

What the sources say

• Supported

  The paper reports that reduced plaque burden, number, and size in p16-3MR mice were reproduced with INK-ATTAC and the senolytic ABT263 (passage 1, page unavailable). It also reports attenuated plaque progression after senescent-cell clearance and reduced expression of inflammatory cytokines and matrix metalloproteases associated with the SASP (indexed passages, page unavailable). (LLM, conf=0.92)

  cites [175] Childs, B. G. et al. Senescent intimal foam cells are deleterious at all stages of atherosclerosis. Science 354, 472–477 (2016). source

In the paper

“In addition, through SASP, senescent cells contribute to cancer development162,163 and metastasis164, treatment failure and increased risk of recurrence165.”

What the sources say

• ?Not checked — no full text of the sourcecites [162] Yoshimoto, S. et al. Obesity-induced gut microbial metabolite promotes liver cancer through senescence secretome. Nature 499, 97–101 (2013). source
• Supported

  The citation is attached to cancer development, not the separately cited claims about metastasis, treatment failure, or recurrence. The Discussion reports that persistent SASP activation mediates paracrine cell transformation and tumourigenesis in the mouse models. (LLM, conf=0.93)

  cites [163] Gonzalez-Meljem, J. M. et al. Stem cell senescence drives age-attenuated induction of pituitary tumours in mouse models of paediatric craniopharyngioma. Nat. Commun. 8, 1819 (2017). source
• Supported

  The citation appears attached to the cancer-development portion of the sentence. The Introduction describes protumorigenic effects of the SASP, and the Discussion reports delayed pancreatic cancer progression when the SASP was impaired. The later claims about metastasis, treatment failure, and recurrence have separate citations. (LLM, conf=0.90)

  cites [164] Lau, L., Porciuncula, A., Yu, A., Iwakura, Y. & David, G. Uncoupling the senescence-associated secretory phenotype from cell cycle exit via interleukin-1 inactivation unveils its protumorigenic role. Mol. Cell. Biol. 39, e00586-18 (2019). source
• Partly supported

  The Results section (“Cancer spread and relapse”; page unavailable) reports that removing therapy-induced senescent host cells prevented or delayed relapse in a mouse breast-cancer model. The Discussion links these cells to inflammatory SASP factors and to treatment-limiting toxicity. The paper does not establish that SASP itself causes treatment failure or increased recurrence risk across cancers; the relapse evidence is limited to the mouse model. (LLM, conf=0.84)

  cites [165] Demaria, M. et al. Cellular senescence promotes adverse effects of chemotherapy and cancer relapse. Cancer Discov. 7, 165–176 (2017). sourceExperimental — accuracy not yet measured

In the paper

“it was recently reported that the clonogenic properties of HSCs are impaired when they are exposed to SASP factors derived from senescent stromal cells180, suggesting that senescence may also affect regeneration in a paracrine fashion.”

What the sources say

• Supported

  The Results section reports that young HSPC exposed to conditioned medium from aged mesenchymal stromal cells formed fewer colonies than controls. It also reports that inhibiting SASP in those stromal cells improved HSPC clonogenicity, supporting the attributed paracrine effect. Page numbers are not provided in our copy. (LLM, conf=0.92)

  cites [180] Gnani, D. et al. An early-senescence state in aged mesenchymal stromal cells contributes to hematopoietic stem and progenitor cell clonogenic impairment through the activation of a pro-inflammatory program. Aging Cell 18, e12933 (2019). source

In the paper

“it cannot be ruled out that the positive effects of senolysis in atherosclerosis-prone mice175 are the consequence of elimination of inflammatory macrophages.”

What the sources say

• Supported

  The paper reports that senescent foam-cell macrophages in early lesions increase inflammatory cytokines and that removing them led to marked lesion regression (passage 5, section labeled Abstract; page unavailable). This supports the citing sentence’s qualified possibility that eliminating inflammatory macrophages contributed to the benefits observed in atherosclerosis-prone mice. (LLM, conf=0.87)

  cites [175] Childs, B. G. et al. Senescent intimal foam cells are deleterious at all stages of atherosclerosis. Science 354, 472–477 (2016). source

In the paper

“However, prolonged exposure to the SASP resulted in paracrine-induced senescence, indicating that, at least in vivo, the effects are dependent on the composition and length of exposure to the SASP.”

What the sources say

• Partly supported

  The Results and Discussion report that prolonged SASP exposure can lead to paracrine senescence, while transient exposure promotes regeneration. The Discussion also links outcomes to exposure duration or strength and the target cell’s status. Our copy does not establish that the effects depend on SASP composition, so that part of the attributed conclusion is unsupported. (LLM, conf=0.86)

  cites [189] Ritschka, B. et al. The senescence-associated secretory phenotype induces cellular plasticity and tissue regeneration. Genes Dev. 31, 172–183 (2017). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [190] Chiche, A. et al. Injury-induced senescence enables in vivo reprogramming in skeletal muscle. Cell Stem Cell 20, 407–414.e404 (2017). source

In the paper

“In agreement with studies performed on INK-ATTAC naturally aged mice194, treatment of advanced-age mice with a combination of dasatinib and quercetin improved physical function and increased lifespan174.”

What the sources say

• Supported

  The Results section reports that intermittent dasatinib plus quercetin (D+Q) improved several measures of physical function in 20-month-old wild-type mice. It also reports that treatment beginning at 24–27 months increased median post-treatment lifespan by 36% compared with vehicle. These findings support the claim about advanced-age mice. (LLM, conf=0.94)

  cites [174] Xu, M. et al. Senolytics improve physical function and increase lifespan in old age. Nat. Med. 24, 1246–1256 (2018). This study demonstrates that transplanting senescent cells in young mice causes persistent physical dysfunction that can be alleviated by senolytic drugs. source

In the paper

“A second study using the INK-ATTAC system in naturally aged mice corroborated these findings194 and increased median lifespan of both male and female mice in different genetic backgrounds and increased healthspan, as indicated by reduced kidney scarring, cardiomyocyte hypertrophy, cardiac stress intolerance, cataractogenesis and lipodystrophy194.”

What the sources say

• Supported

  Split into 2 atoms — 2 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites [194] Baker, D. J. et al. Naturally occurring p16(Ink4a)-positive cells shorten healthy lifespan. Nature 530, 184–189 (2016). source

In the paper

“By contrast, short-term exposure to the SASP promoted expression of stem cell markers and increased the regenerative capacity of mouse keratinocytes189 and of skeletal muscle190 in vivo.”

What the sources say

• Supported

  The citation to this paper is attached to the mouse-keratinocyte finding, not the separately cited skeletal-muscle finding. In the Results (Fig. 5), two-day exposure to senescent-cell conditioned medium increased stem-cell gene expression in primary mouse keratinocytes; grafts containing those cells subsequently formed more hair follicles in mice. (LLM, conf=0.93)

  cites [189] Ritschka, B. et al. The senescence-associated secretory phenotype induces cellular plasticity and tissue regeneration. Genes Dev. 31, 172–183 (2017). source
• ?Not checked — no full text of the sourcecites [190] Chiche, A. et al. Injury-induced senescence enables in vivo reprogramming in skeletal muscle. Cell Stem Cell 20, 407–414.e404 (2017). source

In the paper

“In senescent cells, FOXO4 binds to p53 to localize it to the nucleus. If this interaction is disrupted by the administration of an inverse peptide, p53 is excluded from the nucleus, initiating cytochrome c release from the mitochondria and apoptosis206.”

What the sources say

• Partly supported

  The Results section on FOXO4-DRI reports that the peptide competes with FOXO4 for p53 binding, excludes active p53 from the nucleus, and induces apoptosis in senescent cells (page unavailable). The paper reports mitochondrial cytochrome c release after FOXO4 inhibition by shRNA, not specifically after administration of FOXO4-DRI; that step in the claimed peptide-induced sequence is not established by our copy. (LLM, conf=0.88)

  cites [206] Baar, M. P. et al. Targeted apoptosis of senescent cells restores tissue homeostasis in response to chemotoxicity and aging. Cell 169, 132–147 e116 (2017). sourceExperimental — accuracy not yet measured

In the paper

“Recently, the cardiac glycoside ouabain demonstrated senolytic activity, at least in part, through the induction of NOXA, a proapoptotic BCL-2 family protein203,204.”

What the sources say

• Supported

  The Results section, “Cardiac glycosides induce apoptosis of senescent cells,” reports that ouabain selectively kills senescent cells. The Results section, “Mechanism explaining the senolytic properties of cardiac glycosides,” identifies NOXA as a pro-apoptotic Bcl2-family protein and says the senolytic effect is partially dependent on it. (LLM, conf=0.94)

  cites [203] Guerrero, A. et al. Cardiac glycosides are broad-spectrum senolytics. Nat. Metab. 1, 1074–1088 (2019). source
• Partly supported

  The Results section, “High-throughput compound screening for senolytic activity” (page unavailable), reports senolytic activity for ouabain in senescent human cells. The copy does not report that ouabain induces NOXA or that NOXA contributes to its senolytic effect; a search for NOXA found no supporting passage. (LLM, conf=0.88)

  cites [204] Triana-Martinez, F. et al. Identification and characterization of cardiac glycosides as senolytic compounds. Nat. Commun. 10, 4731 (2019). sourceExperimental — accuracy not yet measured

In the paper

“the SASP component interferon-γ induces cellular senescence and tissue ageing in mice with shortened telomeres, and abrogation of interferon-γ signalling rescues ageing-related phenotypes and extends lifespan187.”

What the sources say

• Partly supported

  The Results section identifies Ifng among inflammatory cytokines associated with the senescence-associated secretome. But the senescence experiments concern type I interferon signaling through IFNAR1 in oncogene-driven models, not interferon-γ signaling in mice with shortened telomeres. The paper does not report rescue of ageing-related phenotypes or extended lifespan. (LLM, conf=0.88)

  cites [187] Katlinskaya, Y. V. et al. Suppression of type I interferon signaling overcomes oncogene-induced senescence and mediates melanoma development and progression. Cell Rep. 15, 171–180 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Additionally, rapamycin treatment increased lifespan and delayed certain ageing-related dysfunctions in mice234.”

What the sources say

• Partly supported

  The Abstract reports that rapamycin extended median and maximal lifespan in mice. It does not establish that ageing-related dysfunctions were delayed; the paper says that demonstrating altered ageing would require testing age-dependent changes in multiple organs and processes. (LLM, conf=0.88)

  cites [234] Harrison, D. E. et al. Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature 460, 392–395 (2009). sourceExperimental — accuracy not yet measured

In the paper

“Treatment with rapamycin (and its analogue RAD001)232 attenuated the protumorigenic SASP230, prevented senescence233, impaired SASP-mediated immune recognition of oncogene-expressing cells and ameliorated liver dysfunction in naturally aged mice231.”

What the sources say

• Partly supported

  The Results section ('mTOR inhibition also blunts the tumour suppressive effects of the SASP'; page unavailable) reports that rapamycin impaired SASP induction and reduced immune-cell infiltration in mice with oncogene-expressing hepatocytes, supporting the immune-surveillance part of the claim. The Results section ('mTOR inhibition prevents the induction of the SASP'; page unavailable) reports lower liver SASP levels in aged rapamycin-treated mice, but does not report improved liver dysfunction. The RAD001, protumorigenic-SASP and senescence clauses have separate citations in the citing sentence and are not judged here. (LLM, conf=0.88)

  cites [230] Herranz, N. et al. mTOR regulates MAPKAPK2 translation to control the senescence-associated secretory phenotype. Nat. Cell Biol. 17, 1205–1217 (2015). sourceExperimental — accuracy not yet measured
• Supported

  The citation to this paper is attached to “prevented senescence,” not to the sentence’s separate claims about RAD001, immune recognition, or liver function. The Abstract and Results and discussion report anti-senescence effects of rapamycin delivery in old human dermal fibroblasts and a doxorubicin-induced senescent-cell model. (LLM, conf=0.89)

  cites [233] Thapa, R. K. et al. Progressive slowdown/prevention of cellular senescence by CD9-targeted delivery of rapamycin using lactose-wrapped calcium carbonate nanoparticles. Sci. Rep. 7, 43299 (2017). source
• Supported

  Citation 230 is attached to attenuation of the protumorigenic SASP, not to the sentence’s other outcomes. In the Results sections “Rapamycin decreases the SASP” and “Rapamycin represses the ability of senescent cells to stimulate cell proliferation and tumorigenesis in vivo” (page numbers unavailable), the paper reports reduced SASP-factor secretion and reduced tumour growth with rapamycin. (LLM, conf=0.93)

  cites [231] Laberge, R. M. et al. MTOR regulates the pro-tumorigenic senescence-associated secretory phenotype by promoting IL1A translation. Nat. Cell Biol. 17, 1049–1061 (2015). source

In the paper

“The use of telomeric ASOs in a mouse model of Hutchinson–Gilford progeria syndrome (an accelerated ageing syndrome) effectively reduced DDR activation, the levels of senescence markers and SASP induction, improved tissue homeostasis and extended lifespan251.”

What the sources say

• Partly supported

  The Results sections on the HGPS mouse model report reduced skin DDR activation and basal-layer p16-positive cells after telomeric ASO treatment, while the skin-homeostasis Results and Discussion report improved skin pathology and longer survival with anti-teloG. The paper does not establish a general reduction in SASP induction in the mice: it reports variable effects on inflammatory cytokines, with significant reductions for IL-1a and IL-8, and anti-teloC did not extend survival. No page numbers are available in our copy. (LLM, conf=0.84)

  cites [251] Aguado, J. et al. Inhibition of DNA damage response at telomeres improves the detrimental phenotypes of Hutchinson-Gilford progeria syndrome. Nat. Commun. 10, 4990 (2019). sourceExperimental — accuracy not yet measured

In the paper

“In mouse models recapitulating these features, adeno-associated virus particles delivering Tert have been shown to reduce DDR and the level of senescence markers and improve lung function265.”

What the sources say

• Supported

  The Results section on apoptosis and cellular senescence reports reduced γH2AX DNA-damage staining and lower p21 and p53 senescence-marker levels in AAV9-Tert-treated fibrotic lungs. The Results section on lung health reports improved pulmonary function compared with AAV9-Empty-treated mice. Page numbers are unavailable in our copy. (LLM, conf=0.94)

  cites [265] Povedano, J. M. et al. Therapeutic effects of telomerase in mice with pulmonary fibrosis induced by damage to the lungs and short telomeres. eLife https://doi.org/10.7554/eLife.31299 (2018). source

In the paper

“Additionally, SASP establishment and the secretion of SASP factors can be modulated by inhibiting HSP90 (REFS214,249).”

What the sources say

• Partly supported

  The Results section, “Reduction of other senescence markers by HSP90 inhibitors” (page unavailable), reports reduced expression of the SASP factor IL-6 after 17-DMAG treatment. It does not show that HSP90 inhibition modulates SASP establishment or measure secretion of SASP factors; the paper primarily describes a senolytic effect. (LLM, conf=0.85)

  cites [214] Fuhrmann-Stroissnigg, H. et al. Identification of HSP90 inhibitors as a novel class of senolytics. Nat. Commun. 8, 422 (2017). sourceExperimental — accuracy not yet measured
• ?Could not verify

  The Introduction and Discussion passages address mouse lifespan, metabolic effects, and inflammation, but do not address HSP90 inhibition or SASP establishment and secretion. Searches for HSP90, SASP, and the senescence-associated secretory phenotype found no passage supporting the attributed claim. (LLM, conf=0.76)

  cites [249] Harrison, D. E. et al. Acarbose, 17-α-estradiol, and nordihydroguaiaretic acid extend mouse lifespan preferentially in males. Aging Cell 13, 273–282 (2014). sourceExperimental — accuracy not yet measured

In the paper

“Systemic delivery of Tert reduces several senescence markers and ageing-related conditions and extends the lifespan of wild-type mice, thus demonstrating that telomeric DDR activation plays a role in natural ageing263.”

What the sources say

• Partly supported

  The Results and Discussion report reduced p16 in most tissues, improved age-related health measures, and longer lifespan after AAV9-mTERT treatment of normal mice. The Discussion also links telomere-derived DNA damage to ageing, but the passages do not establish the more specific claim that activation of the telomeric DNA-damage response (DDR) contributes to natural ageing. Page numbers were not provided in our copy. (LLM, conf=0.84)

  cites [263] Bernardes de Jesus, B. et al. Telomerase gene therapy in adult and old mice delays aging and increases longevity without increasing cancer. EMBO Mol. Med. 4, 691–704 (2012). sourceExperimental — accuracy not yet measured

In the paper

“However, the overlap between the extracellular markers identified by the aforementioned strategies is low, when each experiment identified distinct markers, suggesting that such markers might be specific to the cell of origin and/or to the mechanism of senescence induction.”

What the sources say

• ?Not checked — no full text of the sourcecites [227] Frescas, D. et al. Senescent cells expose and secrete an oxidized form of membrane-bound vimentin as revealed by a natural polyreactive antibody. Proc. Natl Acad. Sci. USA 114, E1668–E1677 (2017). source
• Partly supported

  The Results and Discussion section (page unavailable) reports an unbiased mass-spectrometry search that identified DPP4 as a surface marker in senescent WI-38 fibroblasts. It does not compare markers across different studies or approaches, establish low overlap, or suggest that marker differences depend on cell origin or senescence induction. (LLM, conf=0.82)

  cites [228] Kim, K. M. et al. Identification of senescent cell surface targetable protein DPP4. Genes Dev. 31, 1529–1534 (2017). sourceExperimental — accuracy not yet measured
• Partly supported

  The Results (Proteomic analysis of the expression of proteins associated with the plasma membrane in senescent cells; page unavailable) report limited overlap between markers found in the paper’s two senescence models. The Discussion (page unavailable) suggests marker expression may vary by tissue and triggering stimulus. The paper does not establish the claimed low overlap between different unbiased approaches or experiments across studies. (LLM, conf=0.84)

  cites [229] Althubiti, M. et al. Characterization of novel markers of senescence and their prognostic potential in cancer. Cell Death Dis. 5, e1528 (2014). sourceExperimental — accuracy not yet measured

In the paper

“NAD+/NADH metabolism was identified as a critical regulator of the magnitude of proinflammatory SASP associated with oncogene activation, and this regulation can be independent of senescence-induced growth arrest239.”

What the sources say

• Supported

  In Results, under “NAD+ metabolism governs the strengths of the proinflammatory SASP,” oncogenic RAS increased the NAD+/NADH ratio alongside a significant increase in SASP. The same passage reports that neither RAS nor NMN supplementation affected senescence-associated growth arrest, supporting the claimed independence. (LLM, conf=0.94)

  cites [239] Nacarelli, T. et al. NAD+ metabolism governs the proinflammatory senescence-associated secretome. Nat. Cell Biol. 21, 397–407 (2019). source

In the paper

“Caloric restriction in mice reduced the DDR and improved telomere maintenance258.”

What the sources say

• Supported

  The Results report that dietary restriction significantly reduced intestinal crypt cells positive for γ-H2A.X, a marker of an active DNA damage response. A separate Results section reports improved telomere maintenance in intestinal cells and parts of the liver. The findings concern specific tissues in mice after three months of dietary restriction. (LLM, conf=0.91)

  cites [258] Wang, C. et al. Adult-onset, short-term dietary restriction reduces cell senescence in mice. Aging 2, 555–566 (2010). source

In the paper

“These include, for example, the mammalian target of rapamycin (mTOR) pathway, which coordinates cell growth and metabolism in response to nutrients, and also promotes SASP production through increased translation of subsets of mRNAs, including the membrane-bound and upstream regulator of NF-κB, IL-1α230”

What the sources say

• Partly supported

  The Introduction (page not specified) says mTOR responds to nutrient signals, and the Results report that mTOR inhibition reduces SASP induction and IL-1α mRNA’s association with polysomes. However, the Discussion identifies increased MAPKAPK2 translation—not IL-1α translation—as the mechanism controlling the SASP. The passages do not describe IL-1α as membrane-bound or an upstream NF-κB regulator. (LLM, conf=0.86)

  cites [230] Herranz, N. et al. mTOR regulates MAPKAPK2 translation to control the senescence-associated secretory phenotype. Nat. Cell Biol. 17, 1205–1217 (2015). sourceExperimental — accuracy not yet measured

In the paper

“Caloric restriction has been demonstrated to be the most effective strategy to lengthen healthspan and lifespan, and is efficacious in a range of species from yeast to primates255.”

What the sources say

• Partly supported

  The Introduction (page not provided) says dietary restriction extends average and/or maximum lifespan in species from yeast to rhesus monkeys and delays loss of function and major diseases in rodents and monkeys. The primate dietary-restriction section (page not provided) also reports fewer age-related deaths and diseases in restricted rhesus monkeys. The copy does not establish that caloric restriction is the most effective known strategy. (LLM, conf=0.88)

  cites [255] Fontana, L., Partridge, L. & Longo, V. D. Extending healthy life span–from yeast to humans. Science 328, 321–326 (2010). sourceExperimental — accuracy not yet measured

In the paper

“It is clear that the immune system has the capacity to eliminate senescent cells in certain contexts; however, the clearance process seems to become dysfunctional with age and in disease, possibly explaining the accumulation of senescent cells with age273.”

What the sources say

• Partly supported

  The Introduction says senescent cells are cleared by immune mechanisms, and the Discussion reports that their removal is rapid in young mice but slows with age. The paper considers reduced immune surveillance as one possible explanation, but does not establish that immune clearance becomes dysfunctional with age or in disease; its analysis also points to senescent cells slowing their own removal. The disease-specific part is unsupported. (LLM, conf=0.85)

  cites [273] Karin, O., Agrawal, A., Porat, Z., Krizhanovsky, V. & Alon, U. Senescent cell turnover slows with age providing an explanation for the Gompertz law. Nat. Commun. 10, 5495 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Recently, it was reported that blood exchange between young and old mice led to a significant reduction in cellular senescence and SASP marker expression in multiple aged tissues, while at the same time the levels of senescence markers were increased in the young animals exposed to old blood270.”

What the sources say

• Supported

  The Results report significantly reduced senescence-marker expression in multiple tissues of old mice paired with young mice, alongside increased expression in young mice paired with old mice. The Results also report reduced SASP-marker expression in old heterochronic mice, and the Discussion summarizes the same pattern. The study used heterochronic parabiosis—a shared circulation—rather than a one-time blood exchange; page numbers are not provided in our copy. (LLM, conf=0.93)

  cites [270] Yousefzadeh, M. J. et al. Heterochronic parabiosis regulates the extent of cellular senescence in multiple tissues. Geroscience https://doi.org/10.1007/s11357-020-00185-1 (2020). source

In the paper

“a tight regulatory network in human cancer models was reported, whereby ATM suppresses ARF levels and ARF acts as a secondary barrier to cancer progression when ATM is inactivated31”

What the sources say

• ?Not checked — no full text of the sourcecites [31] Velimezi, G. et al. Functional interplay between the DNA-damage-response kinase ATM and ARF tumour suppressor protein in human cancer. Nat. Cell Biol. 15, 967–977 (2013). source

In the paper

“DDR precedes ARF engagement, whose activation is detected at later stages of cancer progression and less frequently than DDR”

What the sources say

• ?Not checked — no full text of the sourcecites [31] Velimezi, G. et al. Functional interplay between the DNA-damage-response kinase ATM and ARF tumour suppressor protein in human cancer. Nat. Cell Biol. 15, 967–977 (2013). source

In the paper

“Cellular senescence is a stable and terminal state of growth arrest in which cells are unable to proliferate despite optimal growth conditions and mitogenic stimuli”

In the paper

“DDR exerts checkpoint functions to block cell cycle progression and prevent the propagation of corrupted genetic information to daughter cells”

In the paper

“the tumour suppressor p53, which is a target of ATM and its paralogue ATR, is activated and stimulates the expression of the cyclin-dependent kinase inhibitor p21, an essential mediator of senescence-associated cell cycle arrest”

In the paper

“Below a certain length, the loss of telomere-capping factors or protective structures makes critically short telomeres resemble one-ended DSBs and thus triggers a DDR that is very similar to that triggered by DNA DSBs24,32”

What the sources say

• ?Not checked — no full text of the sourcecites [24] d’Adda di Fagagna, F. et al. A DNA damage checkpoint response in telomere-initiated senescence. Nature 426, 194–198 (2003). This study demonstrates that the activation of the DDR pathways by critically short telomeres is key in the enforcement of cellular senescence. source
• ?Not checked — no full text of the sourcecites [32] Herbig, U., Jobling, W. A., Chen, B. P., Chen, D. J. & Sedivy, J. M. Telomere shortening triggers senescence of human cells through a pathway involving ATM, p53, and p21(CIP1), but not p16(INK4a). Mol. Cell 14, 501–513 (2004). source

In the paper

“the tumour suppressor ARF stabilizes p53, which contributes to the induction of senescence28”

What the sources say

• ?Not checked — no full text of the sourcecites [28] Kamijo, T. et al. Tumor suppression at the mouse INK4a locus mediated by the alternative reading frame product p19ARF. Cell 91, 649–659 (1997). source

In the paper

“HDAC inhibitors can also induce cellular senescence in normal human fibroblasts, which may be related to their impact on the DDR56”

What the sources say

• ?Not checked — no full text of the sourcecites [56] Munro, J., Barr, N. I., Ireland, H., Morrison, V. & Parkinson, E. K. Histone deacetylase inhibitors induce a senescence-like state in human cells by a p16-dependent mechanism that is independent of a mitotic clock. Exp. Cell. Res. 295, 525–538 (2004). source

In the paper

“Oncogene activation is a powerful inducer of cellular senescence. Oncogene expression triggers an initial hyperproliferative phase that is intrinsically associated with altered DNA replication, which eventually engages DDR pathways and causes senescence7,8,39”

What the sources say

• ?Not checked — no full text of the sourcecites [7] Di Micco, R. et al. Oncogene-induced senescence is a DNA damage response triggered by DNA hyper-replication. Nature 444, 638–642 (2006). source
• ?Not checked — no full text of the sourcecites [8] Bartkova, J. et al. Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints. Nature 444, 633–637 (2006). source
• ?Not checked — no full text of the sourcecites [39] Halazonetis, T. D., Gorgoulis, V. G. & Bartek, J. An oncogene-induced DNA damage model for cancer development. Science 319, 1352–1355 (2008). source

In the paper

“Like ATM, p38 induces the expression of SASP transcripts by increasing the activity of nuclear factor-κB (NF-κB), suggesting that although DDR and p38 activation are independent, they can converge on SASP activation”

What the sources say

• ?Not checked — no full text of the sourcecites [88] Freund, A., Patil, C. K. & Campisi, J. p38MAPK is a novel DNA damage response-independent regulator of the senescence-associated secretory phenotype. EMBO J. 30, 1536–1548 (2011). source

In the paper

“Thus, BRD4 inhibitors may limit SASP activation but also cause more cellular senescence by promoting telomeric shortening.”

In the paper

“Several transcription factors and chromatin regulators have been implicated in the regulation of SASP, which is controlled mainly at the transcriptional level”

In the paper

“Mature postmitotic adipocytes show strong SA-β-gal staining and SASP induction in a p53-dependent manner in mice subjected to excessive caloric intake, although other markers, such as accumulation of DNA damage, were not reported138.”

What the sources say

• ?Not checked — no full text of the sourcecites [138] Minamino, T. et al. A crucial role for adipose tissue p53 in the regulation of insulin resistance. Nat. Med. 15, 1082–1087 (2009). source

In the paper

“Although some markers of cellular senescence, such as p16 and SA-β-gal activity, were not detected, differentiation of melanocyte stem cells was associated with persistent DDR activation and was enhanced in Atm-knockout mice124.”

What the sources say

• ?Not checked — no full text of the sourcecites [124] Inomata, K. et al. Genotoxic stress abrogates renewal of melanocyte stem cells by triggering their differentiation. Cell 137, 1088–1099 (2009). This study demonstrates that DNA damage can induce stem cell differentiation. source

In the paper

“cGAS–STING genetic depletion reduces the proinflammatory SASP and mitigates senescence immunosurveillance in senescence models in vivo.”

In the paper

“Therefore, the cellular senescence early in life is important for normal development and morphogenesis, and later in life it becomes important for tissue repair and inhibition of cancer outgrowth.”

In the paper

“Over time, although SASP favours proper tissue development, tissue repair and recruitment of immune cells, its persistence may generate chronic inflammation and contribute to ageing-related diseases and, paradoxically, cancer.”

In the paper

“While tumour suppression activity is mediated mainly by cell-autonomous cell cycle arrest, most other senescence functions involve the SASP.”

In the paper

“Inflammageing is a risk factor for various chronic age-associated diseases, including cardiovascular diseases, some cancer types and neurodegeneration, and can be associated with premature death.”

What the sources say

• ?Not checked — no full text of the sourcecites [166] Franceschi, C. et al. Inflamm-aging. An evolutionary perspective on immunosenescence. Ann. N. Y. Acad. Sci. 908, 244–254 (2000). source

In the paper

“Muscle progenitor cells that accumulate damage, both DNA and molecular, and upregulate p16 enter senescence on stimulation and are unable to contribute to muscle regeneration after injury179.”

What the sources say

• ?Not checked — no full text of the sourcecites [179] Sousa-Victor, P., Garcia-Prat, L., Serrano, A. L., Perdiguero, E. & Munoz-Canoves, P. Muscle stem cell aging: regulation and rejuvenation. Trends Endocrinol. Metab. 26, 287–296 (2015). source

In the paper

“These effects could potentially contribute to the spread of senescence in tissues and lead to tissue and organismal dysfunction.”