Alzheimer's Disease–Associated Amyloid-β Precursor Protein Prevents Aging Stress–Induced Mitophagy and Fumarate Depletion to Improve Antitumor Immunity

AD patients have a decreased incidence of cancer, with up to a 50% decrease reported.

“Alzheimer’s disease (AD) patients have a decreased incidence of cancer.”

• Also stated in: § Introduction · plain

  “The inverse association between Alzheimer’s disease (AD) and cancer incidence, with up to a 50% decrease, has been reported with an unknown mechanism (1–3).”

• cites [1] Driver, 2012, Inverse association between cancer and Alzheimer’s disease: results from the Framingham Heart Study, BMJ sourcePartly supported

  The Results (Incident Alzheimer’s disease and risk of cancer) report a lower risk of subsequent cancer among participants with probable Alzheimer’s disease, supporting the printed citing sentence. The added claim of a decrease of ‘up to 50%’ does not match the reported estimate: the risk ratio was 0.39, corresponding to a 61% decrease. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [2] Lanni, 2021, Cancer and Alzheimer’s disease inverse relationship: an age-associated diverging derailment of shared pathways, Mol Psychiatry sourceNot checked — no full text of the source
• cites [3] Musicco, 2013, Inverse occurrence of cancer and Alzheimer disease: a population-based incidence study, Neurology sourceNot checked — no full text of the source

Aging is associated with alterations in mitochondrial function and mitochondrial dynamics in memory T cells.

“The changes in the adaptive immune system, namely T-cells, with aging has been reported; memory T-cell function substantially decreases with aging (8,9), with alterations in mitochondrial function and mitochondrial dynamics (8–10).”

• cites [8] Kishton, 2017, Metabolic regulation of T cell longevity and function in tumor immunotherapy, Cell Metab sourcePartly supported

  The sections on T cell longevity and in vitro metabolism link mitochondrial function and dynamics to memory T cell persistence and T cell activity. They do not establish that aging causes those mitochondrial alterations in memory T cells; the paper’s discussion of aging concerns cellular and organismal longevity more generally. Page numbers are not available in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [9] Vaena, 2021, Aging-dependent mitochondrial dysfunction mediated by ceramide signaling inhibits antitumor T cell response, Cell Rep sourceSupported
• cites [10] Bektas, 2019, Age-associated changes in human CD4+ T cells point to mitochondrial dysfunction consequent to impaired autophagy, Aging (Albany NY) sourcePartly supported

  The Results section on mitochondrial morphology reports dysmorphic mitochondria and undegraded autophagic compartments in older participants’ memory CD4+ T cells, supporting an age-related alteration in mitochondrial turnover. The respiration Results find reduced mitochondrial function in older participants’ CD4+ T cells overall, but do not establish that reduction specifically in memory T cells. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Memory T-cell function substantially decreases with aging.

“The changes in the adaptive immune system, namely T-cells, with aging has been reported; memory T-cell function substantially decreases with aging (8,9), with alterations in mitochondrial function and mitochondrial dynamics (8–10).”

• cites [8] Kishton, 2017, Metabolic regulation of T cell longevity and function in tumor immunotherapy, Cell Metab sourceCould not verify

  The sections on T-cell differentiation and metabolic activity discuss memory T-cell longevity and function, but do not say that memory T-cell function decreases with age. The section on metabolism and epigenetics discusses aging in cells and organisms generally, without making that connection. I searched for aging and age-related changes in memory T cells. (LLM, conf=0.72)

  Experimental — accuracy not yet measured
• cites [9] Vaena, 2021, Aging-dependent mitochondrial dysfunction mediated by ceramide signaling inhibits antitumor T cell response, Cell Rep sourceSupported

Previous studies demonstrated the accumulation of amyloid-beta precursor protein (APP) and its products amyloid β (Aβ40 and Aβ42) and C-terminal fragments (APP-CTF) in the outer mitochondrial membrane through association with TOMM complex (including Tom20/40 proteins), which inhibits mitophagy.

“Previous studies demonstrated the accumulation of amyloid-beta precursor protein (APP) and its product amyloid β (Aβ40 and Aβ42) and C-terminal fragments (APP-CTF) in the outer mitochondrial membrane through association with TOMM complex (including Tom20/40 proteins), which inhibits mitophagy (21,22).”

• cites [21] Lee, 2022, Accumulation of APP-CTF induces mitophagy dysfunction in the iNSCs model of Alzheimer’s disease, Cell Death Discov sourcePartly supported

  The Results section reports increased APP-CTFs in mitochondrial fractions of AD patient-derived iNSCs, and the Discussion links APP-CTFs to mitophagy dysfunction. Our copy does not establish that APP, Aβ40, and Aβ42 accumulate in the outer mitochondrial membrane through association with the TOMM complex or Tom20/40. Page numbers are not provided. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [22] Vaillant-Beuchot, 2021, Accumulation of amyloid precursor protein C-terminal fragments triggers mitochondrial structure, function, and mitophagy defects in Alzheimer’s disease models and human brains, Acta Neuropathol sourcePartly supported

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

  Experimental — accuracy not yet measured

APP is expressed and processed in T-cells at low levels.

“APP is expressed and processed in T-cells at low levels (26) – accumulation and processing of APP lead to mitophagic changes in neurons (27).”

• cites [26] Delvaux, 2013, Differential processing of amyloid precursor protein in brain and in peripheral blood leukocytes, Neurobiol Aging sourcePartly supported

  The Results (§3.1) show APP immunoreactivity in peripheral blood leukocytes, and the Discussion (§4) describes evidence of APP processing in those cells. But the Discussion explicitly says the authors did not distinguish leukocyte subclasses, so the paper does not establish the claim specifically for T-cells or show that their APP levels are low. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

The increase in ceramide-dependent mitophagy in aging T-cells is detrimental to their anti-tumor function.

“While the increase in ceramide-dependent mitophagy in aging T-cells is detrimental to their anti-tumor function (9), homeostatic mild mitophagy in aging neurons is essential for healthy aging and mitochondrial quality control.”

• cites [9] Vaena, 2021, Aging-dependent mitochondrial dysfunction mediated by ceramide signaling inhibits antitumor T cell response, Cell Rep sourceSupported

APP is directly involved in the inhibition of mitophagy.

“It is directly involved in the inhibition of mitophagy (27,39), which was seen in the tumor-infiltrating lymphocytes in both in vivo tumor models (Figure 1).”

• cites [27] Lopez Sanchez, 2017, Amyloid precursor protein drives down-regulation of mitochondrial oxidative phosphorylation independent of amyloid beta, Sci Rep sourceCould not verify

  The Results and Discussion report that increased APP reduces mitochondrial respiration and oxidative phosphorylation in neuroblastoma cells. Searches for mitophagy inhibition and mitochondrial clearance found no passage addressing whether APP inhibits mitophagy; reduced respiration does not establish that claim. Page numbers are unavailable in our copy. (LLM, conf=0.76)

  Experimental — accuracy not yet measured
• cites [39] Atamna, 2007, Mechanisms of mitochondrial dysfunction and energy deficiency in Alzheimer’s disease, Mitochondrion sourceNot checked — no full text of the source

The bioactive sphingolipid ceramide is implicated in modulating mitochondrial metabolism and suppressing anti-tumor responses in aging T-cells.

“Memory T-cells depend on mitochondrial and lipid metabolism for function and survival (11), and the bioactive sphingolipid ceramide was implicated in modulating mitochondrial metabolism and suppressing anti-tumor responses in aging T-cells (9).”

• cites [9] Vaena, 2021, Aging-dependent mitochondrial dysfunction mediated by ceramide signaling inhibits antitumor T cell response, Cell Rep sourceSupported

Succination of proteins at catalytic cysteine residues regulates protein functions.

“This chemical modification of proteins at the catalytic cysteine residues regulates protein functions (46).”

• cites [46] Blatnik, 2008, Succination of proteins by fumarate: mechanism of inactivation of glyceraldehyde-3-phosphate dehydrogenase in diabetes, Ann N Y Acad Sci sourcePartly supported

  The Results (page unavailable) identify GAPDH’s active-site Cys-149 as a site of succination and state that modification of it can inactivate the enzyme. The paper supports an effect on GAPDH activity, but does not establish the broader claim that succination at catalytic cysteines regulates the functions of proteins generally. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

Parkin (PRKN) is one of the proteins with a catalytic cysteine involved in ceramide-dependent mitophagy.

“One of the proteins with a catalytic cysteine involved in ceramide-dependent mitophagy is Parkin (PRKN) (29).”

• cites [29] Oleinik, 2019, Mitochondrial protein import is regulated by p17/PERMIT to mediate lipid metabolism and cellular stress, Sci Adv sourceCould not verify

  The Results section describes ceramide-dependent mitophagy involving p17/PERMIT, CerS1, Drp1, and LC3, but does not identify Parkin as a participant or describe a catalytic cysteine in Parkin. A reference title mentions Parkin in relation to mitophagy, but not ceramide-dependent mitophagy; searches for Parkin and catalytic cysteine found no passage supporting the attributed claim. No page numbers are available in our copy. (LLM, conf=0.72)

  Experimental — accuracy not yet measured

Mutant APP lacking mitochondrial targeting domain (residues 40-51) showed decreased localization to mitochondria of Jurkat cells than WT-APP.

“We generated a mutant APP that does not localize to the mitochondria by deleting the mitochondrial targeting domain (residues 40–51) (42). We then compared the protection against mitophagy in Jurkat cells expressing either WT-APP or the mutant (Mut)-APP, which showed decreased localization to the mitochondria of the Jurkat cells than the WT-APP (Figure 3G, H).”

• cites [42] Anandatheerthavarada, 2003, Mitochondrial targeting and a novel transmembrane arrest of Alzheimer’s amyloid precursor protein impairs mitochondrial function in neuronal cells, J Cell Biol sourceSupported

Succination is a post-translational modification resulting from increased fumarate levels.

“Succination is a post-translational modification resulting from increased fumarate levels (46).”

• cites [46] Blatnik, 2008, Succination of proteins by fumarate: mechanism of inactivation of glyceraldehyde-3-phosphate dehydrogenase in diabetes, Ann N Y Acad Sci sourceSupported

One of the metabolic signatures of ceramide-dependent mitophagy in aging neurons is the depletion of fumarate.

“One of the metabolic signatures of ceramide-dependent mitophagy in aging neurons is the depletion of fumarate (41).”

• cites [41] Jankowsky, 2004, Mutant presenilins specifically elevate the levels of the 42 residue beta-amyloid peptide in vivo: evidence for augmentation of a 42-specific gamma secretase, Hum Mol Genet sourceCould not verify

  The Introduction (p. 2) and Discussion (p. 4) address presenilin mutations, amyloid-β levels, and amyloid deposition. Searches for fumarate, ceramide, and mitophagy found no passage addressing fumarate depletion during ceramide-dependent mitophagy in aging neurons. (LLM, conf=0.77)

  Experimental — accuracy not yet measured

Mitochondrial localization of APP/Aβ40 improves anti-tumor functions of aging T-cells.

“Here, we demonstrated that mitochondrial localization of AD-associated amyloid-β precursor protein (APP) and its cleavage product amyloid-β 40, but not mutant APP that lacks a mitochondrial localization signal, inhibits lipid stress-mediated hyperactive mitophagy in aging T-cells, improving their anti-tumor functions.”

APP interaction with TOMM complex at the outer mitochondrial membrane attenuated trafficking of ceramide synthase CerS6 to mitochondria in aging AD T-cells.

“Mechanistically, APP interaction with TOMM complex at the outer mitochondrial membrane attenuated trafficking of ceramide synthase CerS6 to mitochondria in aging AD T-cells, preventing ceramide-dependent mitophagy.”

Fumarate depletion in stress-dependent mitophagy in T cells is linked to enhanced mitochondrial damage.

“The metabolic signature of stress-dependent mitophagy in T cells showed fumarate depletion, which was linked to decreased succination of Parkin and enhanced mitochondrial damage.”

Adoptive cell transfer (ACT)-based immunotherapy using aging T cells isolated from AD mice suppressed tumor growth.

“Additionally, adoptive cell transfer (ACT)-based immunotherapy using aging T cells isolated from AD mice suppressed tumor growth.”

Mitochondrial localization of AD-associated APP and its cleavage product amyloid-β 40, but not mutant APP that lacks a mitochondrial localization signal, inhibits lipid stress-mediated hyperactive mitophagy in aging T-cells.

“Here, we demonstrated that mitochondrial localization of AD-associated amyloid-β precursor protein (APP) and its cleavage product amyloid-β 40, but not mutant APP that lacks a mitochondrial localization signal, inhibits lipid stress-mediated hyperactive mitophagy in aging T-cells, improving their anti-tumor functions.”

Growth of melanoma xenograft or carcinogen-induced oral cancer models was highly reduced in AD mice.

“Growth of melanoma xenograft or carcinogen-induced oral cancer models was highly reduced in AD mice.”

Fumarate depletion in stress-dependent mitophagy in T cells is linked to decreased succination of Parkin.

“The metabolic signature of stress-dependent mitophagy in T cells showed fumarate depletion, which was linked to decreased succination of Parkin and enhanced mitochondrial damage.”

The metabolic signature of stress-dependent mitophagy in T cells showed fumarate depletion.

“The metabolic signature of stress-dependent mitophagy in T cells showed fumarate depletion, which was linked to decreased succination of Parkin and enhanced mitochondrial damage.”

12 mo 3xTg T-cells secreted lower levels of IL-10 upon TCR stimulation via plate-bound CD3 and CD28 antibodies compared to 12 mo WT T-cells.

“12 mo 3xTg T-cells secreted lower levels of the anti-inflammatory cytokine, IL-10, upon TCR stimulation via plate-bound CD3- and CD28 antibodies compared to 12 mo WT T-cells (Figure 2B, C).”

Elevated mitophagy with fumarate depletion in T cells from aging donors was restored in T cells isolated from age-matched AD patients.

“Moreover, T cells isolated from aging donors showed elevated mitophagy with fumarate depletion, which was restored in T cells isolated from age-matched AD patients.”

APP improved anti-tumor functions of AD T cells in vitro and in vivo.

“Thus, APP restored mitochondrial fumarate metabolism and Parkin succination, improving anti-tumor functions of AD T cells in vitro and in vivo.”

3xTg TILs demonstrated lower mitophagy than WT TILs by PLA measuring LC3-Tom40 interaction in CD3+ T-cells.

“The 3xTg TILs demonstrated lower levels of mitophagy than WT TILs, as demonstrated by the proximity ligation assay (PLA) measuring LC3-Tom40 interaction specifically in the CD3+ T-cells in the tumors (Figure 1I).”

LC3-Tom40 colocalization was decreased in 3xTg tongues compared to WT controls.

“LC3-Tom40 colocalization was decreased in the 3xTg tongues compared to WT controls, indicating a lower level of mitophagy in these 3xTg T-cells than in WT tumor-infiltrating T-cells (Figure 1B, C).”

Depletion of T-cells in 3xTg mice using anti-CD3 antibody completely abolished protection against tumor growth.

“When the T-cells in the 3xTg mice were depleted using an anti-CD3 antibody (Figure S1E), the protection of these mice against tumor growth was completely abolished (Figure 1E).”

3xTg tongues were protected against Treg (FoxP3+ CD4+ T-cells) infiltration.

“The 3xTg tongues were protected against Treg (FoxP3+ CD4+ T-cells) infiltration as revealed by multiplex staining (Figure S1C, Figure 1D), thereby fostering a more aggressive anti-tumor environment in these 3xTg tongues.”

CD8+ T-cell to Treg infiltration ratio was higher in 3xTg tongues.

“The CD8+ T-cell infiltration to T-reg infiltration ratio (CD8+ T-cells/Foxp3+ T-cells detected by multiplex staining) was higher in the 3xTg tongues (Figure S1C), suggesting a pro-inflammatory T-cell infiltration.”

3xTg T-cells (12 mo) were protected against age-induced decline in IFNγ cytokine secretion in both CD4+ and CD8+ populations compared to age-matched WT T-cells.

“While the viability of T-cells from 12 mo AD mice was comparable to that of the age-matched WT T-cells (Figure 2A), 3xTg T-cells (12 mo) were protected against the age-induced decline in IFNγ cytokine secretion in both the CD4+ and CD8+ populations compared to age-matched WT T-cells.”

T cells isolated from aging donors showed elevated mitophagy with fumarate depletion.

“Moreover, T cells isolated from aging donors showed elevated mitophagy with fumarate depletion, which was restored in T cells isolated from age-matched AD patients.”

Tongues from WT mice showed significantly higher Ki67 staining by IHC compared to 3xTg tongues.

“Tongues from WT mice showed a significantly higher level of Ki67 staining by immunohistochemistry (IHC) compared to the 3xTg tongues, indicating an increase in cellular proliferation in the WT tongue tumors (Figure S1B).”

APP-PS1 mice compared to age-matched WT (12 mo) were not protected against tumor growth.

“When another AD mouse model, the APP-PS1, was compared to age-matched WT control mice (12 mo), they were not protected against tumor growth (Figure 1J).”

Viability of T-cells from 12 mo AD mice was comparable to age-matched WT T-cells.

“While the viability of T-cells from 12 mo AD mice was comparable to that of the age-matched WT T-cells (Figure 2A), 3xTg T-cells (12 mo) were protected against the age-induced decline in IFNγ cytokine secretion in both the CD4+ and CD8+ populations compared to age-matched WT T-cells.”

12 mo 3xTg mice exhibited protection against growth of subcutaneously implanted B16 melanoma tumors.

“Moreover, 12 mo 3xTg mice exhibited protection against the growth of exogenous, subcutaneously implanted B16 melanoma tumors (Figure 1E, Figure S1D).”

In MEPS, odds of cancer diagnosis were higher for non-AD controls compared to AD cases (OR 21.12, 95% CI 9.01-49.3), adjusting for age, sex, and race/ethnicity.

“The findings of the logistic regression model suggest that the odds of cancer diagnosis were higher (Odds Ratio 21.12 (95% confidence interval: 9.01–49.3) for the non-AD controls compared to the AD cases, adjusting for age, sex, and race/ethnicity.”

• AssumptionRests on an assumption: ICD code G30 accurately identifies AD cases in MEPS.
• AssumptionRests on an assumption: ICD codes used in MEPS accurately identify cancer diagnoses.

In MEPS 2016-2019 and 2021, among adults ≥60, cancer prevalence was higher in non-AD controls (4.9%) than in propensity score-matched AD cases (0.25%) (P<.0001).

“The prevalence of cancer was statistically significantly higher in non-AD controls (4.9%) versus AD cases (0.25%) (P<.0001) (Table 1, Table S1-S4 ).”

• AssumptionRests on an assumption: ICD code G30 accurately identifies AD cases in MEPS.
• AssumptionRests on an assumption: ICD codes used in MEPS accurately identify cancer diagnoses.

3xTg T-cells demonstrated significantly heightened capacity to kill MOC2 tumor cells in culture.

“3xTg T-cells demonstrated a significantly heightened capacity to kill MOC2 tumor cells in culture (Figure 2D), consistent with increased IFNγ secretion.”

12 mo 3xTg T-cells were significantly protected from mitophagy compared to 12 mo WT T-cells.

“While 12 mo WT T-cells demonstrated increased mitophagy upon activation compared to T-cells isolated from 3 mo WT mice, 12 mo 3xTg T-cells were significantly protected from mitophagy compared to 12 mo WT T-cells (Figure 3A).”

Inhibition of β-secretase decreased IFNγ secretion in 12 mo 3xTg T-cells compared to untreated controls.

“Inhibition of β-secretase, which prevents the processing of APP into a C-terminal fragment including the Aβ40 peptide, decreased IFNγ secretion in 12 mo 3xTg T-cells compared to untreated controls (Figure S3J).”

RNA sequencing of aging T-cells from fumarate-treated mice shows reversal of the transcriptional profile of untreated aging T-cells, closely mimicking younger T-cell counterparts after 2-month fumarate treatment.

“RNA sequencing of the aging T-cells collected from fumarate-treated mice showed a reversal of the transcriptional profile of the untreated aging T-cells, closely mimicking their younger T-cell counterparts after the 2-month fumarate treatment (Figure S5D).”

Activated T-cells from fumarate-treated 24-month-old mice secreted less IL-10.

“Activated T-cells isolated from the fumarate-treated 24-month-old mice secreted less IL-10, which is anti-inflammatory, demonstrating the roles of fumarate in restoring the inflammatory potential of aging T-cells (Figure 5J).”

ATAD3 was confirmed to interact with CerS6 in aging T-cells.

“Among the identified proteins, only ATAD3 was confirmed to interact with CerS6 in aging T-cells (Figure 3L-M).”

3xTg T-cells exhibited increased APP levels in total lysates.

“3xTg T-cells exhibited increased APP levels in their total lysates (Figure 2E), and the transgenic 3xTg APP was enriched in their mRNAs (Figure 2F).”

Aβ40, not Aβ42, interacted with mitochondrial Tom20 in 12 mo 3xTg T-cells.

“Aβ40, not Aβ42, interacted with mitochondrial Tom20 in 12 mo 3xTg T-cells (Figures S3A, B).”

Transgenic 3xTg APP was enriched in their mRNAs.

“3xTg T-cells exhibited increased APP levels in their total lysates (Figure 2E), and the transgenic 3xTg APP was enriched in their mRNAs (Figure 2F).”

Exogenous fumarate enhanced tumor-killing function of aging T-cells in polyclonal tumor-killing assay with B16-melanoma cells.

“Exogenous fumarate enhanced the tumor-killing function of aging T-cells shown by the polyclonal tumor-killing assay with B16-melanoma cells (Figure 5K).”

12 mo WT T-cells demonstrated increased mitophagy upon activation compared to 3 mo WT T-cells.

“While 12 mo WT T-cells demonstrated increased mitophagy upon activation compared to T-cells isolated from 3 mo WT mice, 12 mo 3xTg T-cells were significantly protected from mitophagy compared to 12 mo WT T-cells (Figure 3A).”

Aβ40, but not Aβ42, increased tumor-killing potential of 12 mo Pmel T-cells.

“Aβ40, but not Aβ42, increased the tumor-killing potential of 12 mo Pmel T-cells, which have a transgene specifically targeting B16 melanoma cells (Figures S3H).”

Exogenous Aβ42 did not affect mitophagy or mitochondrial ceramide compared to Scr-peptide controls.

“However, exogenous Aβ42 did not affect mitophagy or mitochondrial ceramide compared to Scr-peptide treated controls (Figures S3C, D).”

Cells expressing WT-APP showed superior protection against ceramide-dependent mitophagy compared to Mut-APP counterparts.

“The results showed superior protection against ceramide-dependent mitophagy in the cells expressing WT-APP compared to the Mut-APP counterparts (Figure 3I-K).”

Aging-induced increase in mitochondrial C14-/C16-ceramide was blunted in 12 mo 3xTg compared to WT T-cells.

“The aging-induced increase in mitochondrial C14-/C16- ceramide, measured by lipidomics, was blunted in the 12 mo 3xTg compared to WT T-cells (Figure 3E, Figure S2A).”

Flow cytometry shows decreased percent positivity and mean fluorescence intensity of Foxp3 in CD4+ T-cells upon fumarate treatment or in AD T-cells.

“Flow cytometry confirmed the protection against T-reg induction upon fumarate treatment or in AD T-cells, which showed decreased percent positivity and mean fluorescence intensity (MFI) of Foxp3 in CD4+ T-cells (Figure 5O, P).”

Subcellular fractionation revealed increased APP mainly accumulates in T-cells' mitochondrial fractions.

“Subcellular fractionation revealed that the increased APP mainly accumulates in the T-cells’ mitochondrial fractions (Figure 2G).”

3xTg T-cells showed APP elevation at RNA and protein levels, especially in mitochondria.

“3xTg T-cells showed an APP elevation at the RNA and protein levels, especially in their mitochondria (Figures 2E-I).”

The absence of ASL in mice decreases fumarate levels systemically.

“The absence of ASL in these mice decreases fumarate levels systemically (Figure S5C).”

Inhibition of γ-secretase did not impact IFNγ secretion in 12 mo 3xTg T-cells.

“The inhibition of γ-secretase that cleaves the APP protein downstream to the Aβ40 domain did not impact IFNγ secretion (Figure S3I).”

Exogenous Aβ40 localized to mitochondria as demonstrated by PLA showing colocalization between Aβ40 and Tom40 upon adding exogenous Aβ40 to old WT T-cells.

“Exogenous Aβ40 also localized to the mitochondria as demonstrated by a PLA that showed colocalization between Aβ40 and Tom40 upon adding exogenous Aβ40 to old WT T-cells (Figures S3E).”

Aging AD T-cells from 12 mo 3xTg mice were protected from this metabolic defect.

“Aging AD T-cells isolated from 12 mo 3xTg mice were protected from this metabolic defect (Figure 4B).”

SiRNA-mediated knockdown of ATAD3 in 3 mo WT T-cells attenuated ceramide-dependent mitophagy upon treatment with SoSe.

“SiRNA-mediated knockdown of ATAD3 in 3 mo WT T-cells (Figure S2G) attenuated ceramide-dependent mitophagy upon treatment with SoSe.”

A list of genes is similarly impacted by the addition of fumarate and by the aging AD T-cell phenotype.

“we identified a list of genes that were similarly impacted by the addition of fumarate and by the aging AD T-cell phenotype (Figure 5N).”

Exogenous fumarate increased CD8+ T-cell IFNγ secretion compared to vehicle-treated control T-cells.

“Exogenous fumarate increased CD8+ T-cell IFNγ secretion compared to vehicle-treated control T-cells (Figure 5E).”

ASLKO T-cells showed elevated levels of mitophagy.

“ASLKO T-cells showed elevated levels of mitophagy”

Old mice treated with vehicle and those treated with fumarate performed similarly in Rotarod and Novelty Y-Maze tests.

“The old mice treated with vehicle and those treated with fumarate performed similarly in the Rotarod and Novelty Y-Maze tests (Figure S5B).”

Aging T-cells from 12 mo WT mice demonstrated significant decrease in fumarate, malate, and argininosuccinate compared to 3 mo WT mice.

“Aging T-cells isolated from 12 mo WT mice demonstrated a significant decrease in several mitochondrial metabolites involved in the tricarboxylic acid (TCA) cycle, namely fumarate, malate, and argininosuccinate, compared to their younger counterparts (isolated from 3 mo WT mice) (Figure 4A).”

LC3 and Tom20 colocalization was decreased in T-cells from 12 mo 3xTg compared to WT.

“This was consistent with decreased colocalization of the autophagy protein LC3, and the mitochondrial protein Tom20 in T-cells isolated from 12 mo 3xTg compared to WT T-cell counterparts (Figure 3B).”

IL-10 secretion is decreased by 3xTg T-cells or T-cells treated with fumarate.

“and decreased IL-10 secretion by 3xTg T-cells or T-cells treated with fumarate (Figure 2B, Figure 5J).”

A list of genes is significantly restored in fumarate-treated aging T-cells to the levels detected in younger counterparts compared to vehicle-treated controls.

“we identified a list of genes that were significantly restored in fumarate-treated aging T-cells to the levels detected in their younger counterparts compared to vehicle-treated controls (Figure 5M).”

ASLKO T-cells show elevated mitophagy upon SoSe exposure compared to WT T-cells.

“ASLKO T-cells showed elevated levels of mitophagy upon SoSe exposure compared to their WT counterparts (Figure 5L)”

Several metabolic pathways are significantly enriched within genes decreasing in aging T-cells but recovering upon fumarate treatment.

“An analysis of the pathway changes showed that several metabolic pathways were significantly enriched within the genes decreasing in aging T-cells but recovering upon fumarate treatment (Figure S5E-F)”

12 mo 3xTg T-cells were protected against mitochondrial localization of CerS6.

“12 mo 3xTg T-cells were protected against mitochondrial localization of CerS6 (Figure 3C, D).”

12 mo 3xTg T-cells were protected from interaction between CerS6 and ATAD3.

“12 mo 3xTg T-cells were protected from the interaction between CerS6 and ATAD3 (Figure 3M), consistent with the decrease in mitochondrial CerS6 and C14-/C16-ceramide accumulation in 12 mo 3xTg compared to WT T-cells (Figure 3C-E).”

Gad1, Scd1, and Hsd11b1 are among genes converted to young expression levels upon fumarate treatment or in aging AD T-cells.

“Besides Foxp3, among the genes that were converted to young expression levels upon fumarate treatment or in the aging AD T-cells were Gad1 (glutamate decarboxylase 1), Scd1 (Stearoyl-coA desaturase 1), and Hsd11b1 (hydroxysteroid 11-beta dehydrogenase 1)”

Exogenous fumarate supplementation in aging WT T-cells inhibited mitophagy.

“Exogenous fumarate supplementation in aging WT T-cells (isolated from 12 mo WT mice) inhibited mitophagy (Figure 5A-D).”

Tumor-infiltrating Tregs are reduced in both the 4NQO tumor model and the B16 melanoma tumor model.

“This is consistent with the reduction of tumor-infiltrating Tregs observed in both the 4NQO tumor model and the B16 melanoma tumor model shown in Figure 1 (Figure 1D, H)”

Immunofluorescence confirmed reduction in ceramide accumulation in mitochondria isolated from 12 mo 3xTg compared to WT T-cells.

“Immunofluorescence confirmed the reduction in ceramide accumulation in mitochondria isolated from 12 mo 3xTg compared to WT T-cells (Figure 3F).”

Metabolic flux experiments using 13C-pyruvate or 13C-glutamine showed fumarate and malate levels significantly reduced in aging T-cells compared to younger controls.

“Metabolic flux experiments using 13C-pyruvate or 13C-glutamine yielded similar results, with the levels of fumarate and malate both significantly reduced in the aging T-cells compared to their younger controls, isolated from 12-month-old versus 3-month-old WT mice (Figure S4A, B).”

APP colocalizes with Tom20 in 3xTg T-cells.

“Immunofluorescence (IF) and proximity ligation assay (PLA) experiments demonstrated the colocalization of APP with the mitochondrial outer-membrane protein Tom20 (Figures 2H, I), validating the accumulation of APP in the mitochondria, which might prevent aging-stress-mediated mitophagy, improving anti-tumor T-cell functions.”

AD T-cells have increased IFNγ RNA expression as measured by qPCR.

“AD T-cells had increased IFNγ RNA expression, as measured by qPCR (Figure S7D).”

Parkin recruitment to the mitochondria is considerably lower in cells transfected with mutated C431D Parkin compared to WT-Parkin.

“The level of Parkin recruitment to the mitochondria was considerably lower in the cells transfected with mutated C431D Parkin compared to WT-Parkin (Figure S5H)”

• AssumptionRests on an assumption: The C431D mutation in Parkin mimics succination at C431 and a high fumarate level state.

All APP-high T-cells have high levels of expression of Aβ40 (Aβ40 hi).

“all APP-high T-cells had high levels of expression of Aβ40 (Aβ40 hi) (Figure S7B).”

Human T-cells isolated from 65-year-old donors have decreased malate and fumarate levels compared to 22-year-old donors.

“The data showed decreased malate and fumarate levels in human T-cells isolated from 65 yo compared to 22 yo donors (Figure 7A).”

Old T-cells with AD MitoTransfer inhibit tumor growth.

“The old T-cells with AD MitoTransfer inhibited tumor growth”

In 65-year-old T-cells, CerS6 interaction is increased with both Tom20 and ATAD3.

“In the 65-year-old T-cells, CerS6 interaction was increased with both Tom20 and ATAD3 (Figure 7E, F)”

APP-high T-cells exhibit less mitophagy than APP-low T-cells.

“The APP-high T-cells exhibited less mitophagy than the APP-low T-cells”

Mitophagy is decreased in AD TILs compared to age-matched control cancer patients.

“Data showed decreased mitophagy in the AD TILs compared to age-matched control cancer patients (Figure S7E, F).”

IFNγ secretion by recipient aging WT T-cells significantly increases after MitoTransfer of 3xTg mitochondria.

“which revealed a significant increase in IFNγ secretion by the aging T-cells after MitoTransfer of 3xTg mitochondria (Figure 6L).”

Both CD4+ and CD8+ human T-cells show an increase in mitophagy with age.

“Both CD4+ and CD8+ human T-cells showed an increase in the levels of mitophagy with age”

Despite a limited number of human samples, a notable and significant effect of the AD phenotype/APP expression on T-cell function was observed both in vitro and in tumor tissues.

“Despite a limited number of human samples, we still observed a notable and significant effect of the AD phenotype/APP expression on T-cell function both in vitro and in tumor tissues.”

TILs in tumor tissues from mice in the AD MitoTransfer group show an increase in APP-Tom20 colocalization, indicating they maintained the mitochondria received from AD donor T-cells before ACT.

“The TILs in the tumor tissues collected from the mice in the AD MitoTransfer group showed an increase in APP-Tom20 colocalization, indicating that they maintained the mitochondria they had received from AD donor T-cells before the ACT (Figure S6E).”

Succination is increased in AD TILs compared to control counterparts.

“Data revealed an increased succination in the AD TILs compared to their control counterparts (Figure S7H).”

Fumarate decreased Foxp3 transcription and CD4+ Treg induction in aging T-cells with an unknown mechanism.

“Moreover, fumarate decreased Foxp3 transcription and CD4+ Treg induction in the aging T-cells with an unknown mechanism.”

Recipient T-cells with 3xTg mitochondria have elevated tumor-killing potential in a co-culture assay with B16 tumor cells.

“The recipient T-cells with the 3xTg mitochondria had an elevated tumor-killing potential, as determined by a tumor-killing co-culture assay with B16 tumor cells (Figure 6M).”

Cells transfected with C431D mutant Parkin are significantly protected against the effects of WT-Parkin overexpression on mitophagy and IFNγ secretion.

“the cells transfected with C431D mutant Parkin were significantly protected against these effects.”

• AssumptionRests on an assumption: The C431D mutation in Parkin mimics succination at C431 and a high fumarate level state.

T-cells from 65-year-old donors have reduced IFNγ secretion as measured by ELISA.

“As measured by ELISA, T-cells from 65 yo donors had reduced IFNγ secretion (Figure 7C).”

Mitophagy in CD8+ T-cells isolated from 65-year-old donors is reduced upon adding fumarate.

“and the mitophagy in CD8+ T-cells (isolated from 65 yo donor) was reduced upon adding fumarate (Figure 7B).”

MitoTransfer from 3xTg T-cells to aging WT T-cells is successful, as indicated by increased MTR fluorescence in recipient T-cells.

“the fluorescence of MTR in the recipient T-cells was assessed, revealing increased levels of MTR fluorescence, indicating that the MitoTransfer to aging recipient WT T-cells was successful (Figure 6H).”

Increased expression of APP protein is exclusively in 3xTg-Pmel T-cells.

“Increased expression of the APP protein, specifically in the T-cells, was then measured by Western blotting, which demonstrated an increased level of APP exclusively in the 3xTg-Pmel T-cells (Figure 6B).”

Treating recipient mice with fumarate restores the function of transferred old WT T-cells, enabling them to control tumor growth in all but one animal.

“Treating the recipient mice with fumarate restored the function of the transferred old WT T-cells, enabling them to control tumor growth in all but one animal (Figure 6C, D).”

TILs in AD patient tumors have a higher level of APP localization to their mitochondria, as measured by PLA.

“The TILs in the AD patient tumors had a higher level of APP localization to their mitochondria, as measured by PLA (Figure S7G).”

Fumarate treatment of young Pmel T-cells does not impact their function.

“Fumarate treatment of the young Pmel T-cells did not impact their function.”

Upon fumarate supplementation, reduced Foxp3 expression levels in the AD T-cells mainly addressed CD4+ T-cells.

“Upon fumarate supplementation, reduced Foxp3 expression levels in the AD T-cells mainly addressed CD4+ T-cells.”

APP interaction with TOMM complex at the outer mitochondrial membrane prevents ceramide-dependent mitophagy in aging AD T-cells.

“Mechanistically, APP interaction with TOMM complex at the outer mitochondrial membrane attenuated trafficking of ceramide synthase CerS6 to mitochondria in aging AD T-cells, preventing ceramide-dependent mitophagy.”

AD protects T cells against ceramide-dependent mitophagy and fumarate depletion to enhance anti-tumor functions.

“Together, these findings show that AD protects T cells against ceramide-dependent mitophagy and fumarate depletion to enhance anti-tumor functions.”

T-cells play critical roles in protecting AD mice against tumor growth and progression.

“These data support the critical roles of T-cells in protecting AD mice against tumor growth and progression.”

Memory T-cells depend on mitochondrial and lipid metabolism for function and survival.

“Memory T-cells depend on mitochondrial and lipid metabolism for function and survival (11), and the bioactive sphingolipid ceramide was implicated in modulating mitochondrial metabolism and suppressing anti-tumor responses in aging T-cells (9).”

• cites [11] O’Sullivan, 2018, Memory CD8+ T cells use cell-intrinsic lipolysis to support the metabolic programming necessary for development, Immunity sourceNot checked — no full text of the source

ASL-mediated fumarate protects against excessive mitophagy in T cells.

“confirming the critical role of ASL-mediated fumarate in protecting against excessive mitophagy in T cells.”

The increase in mitophagy in old T-cells and its suppression in 3xTg or fumarate-treated old T-cells is reflected by Parkin succination changes.

“This reflected the increase in mitophagy in the old T-cells and its suppression in the 3xTg or fumarate-treated old T-cells.”

APP processing into Aβ40 by β-secretase is crucial in protecting aging-stress-mediated mitophagy in AD T-cells.

“These data suggest that APP processing into Aβ40 by β-secretase is crucial in protecting aging-stress-mediated mitophagy in AD T-cells.”

Fumarate plays a central role in regulating both aging T-cell mitophagy and metabolism.

“indicating the central role of fumarate in regulating both aging T-cell mitophagy and metabolism.”

Exogenous fumarate improved aging T-cells' anti-tumor functions in ACT-based immunotherapy by protecting them against mitochondrial damage and hyperactive ceramide-dependent mitophagy.

“exogenous fumarate improved aging T-cells’ anti-tumor functions in ACT-based immunotherapy by protecting them against mitochondrial damage and hyperactive ceramide-dependent mitophagy.”

Transferring healthy mitochondria from AD T cells into aging T-cells could be a new therapeutic strategy for improving anti-tumor cellular immunotherapy.

“Our data confirms that transferring healthy mitochondria from AD T cells into aging T-cells could be a new therapeutic strategy for improving anti-tumor cellular immunotherapy.”

• AssumptionRests on an assumption: Mitochondria have an essential role in determining the anti-tumor function of T-cells.

Transfer of AD mitochondria improves anti-tumor functions of aging T cells in vitro and in vivo.

“These data showed that the transfer of AD mitochondria improves anti-tumor functions of aging T cells in vitro and in vivo.”

• AssumptionRests on an assumption: Mitochondria have an essential role in determining the anti-tumor function of T-cells.

MitoTransfer has longer-term clinical potential in cancer therapy.

“demonstrating the longer-term clinical potential of MitoTransfer in cancer therapy.”

ATAD3 plays a vital role in the mitochondrial trafficking of CerS6 from the ER in aging T-cells.

“Here, we demonstrated that ATAD3 plays a vital role in the mitochondrial trafficking of CerS6 from the ER in aging T-cells.”

APP plays a role in mitophagy inhibition.

“reinforcing the role of APP in mitophagy inhibition (Figure S7C).”

Genotyping demonstrates the presence of the Pmel Tg in the 3xTg-Pmel and Ctrl-Pmel mice, indicating both groups have T-cells with TCRs that specifically target B16-melanoma tumors.

“Genotyping of all our mice demonstrated the presence of the Pmel Tg in the 3xTg-Pmel and the Ctrl-Pmel mice, indicating that both groups have T-cells with TCRs that specifically target B16-melanoma tumors.”

AD mitochondria protect against aging-induced decline in anti-tumor T-cell function.

“emphasizing the role of AD mitochondria in protecting against aging-induced decline in anti-tumor T-cell function”

• AssumptionRests on an assumption: Mitochondria have an essential role in determining the anti-tumor function of T-cells.

Succination inhibits Parkin function.

“emphasizing the role of succination in inhibiting Parkin function.”

• AssumptionRests on an assumption: The C431D mutation in Parkin mimics succination at C431 and a high fumarate level state.