Amyloid-β induces lipid droplet-mediated microglial dysfunction via the enzyme DGAT2 in Alzheimer’s disease

In the paper

“are important for immune cell modulation and signaling23”

What the sources say

• Supported

  The paper’s main text (p. 3) links cholesterol from myelin debris to inflammasome stimulation in aged phagocytes. Its opening summary (p. 1) says this produces a maladaptive immune response, supporting the broad claim that lipids can modulate immune cells and their signaling. (LLM, conf=0.86)

  cites [23] Cantuti-Castelvetri, 2018, Defective cholesterol clearance limits remyelination in the aged central nervous system, Science source

In the paper

“Several AD-risk genes such as TREM2, APOE, ABCA7, ABCA1, and CLU are directly related to lipid metabolism.26,27,28,29,30,31”

What the sources say

• Supported

  The Introduction identifies TREM2’s R47H mutation as associated with AD risk and says it impairs binding to anionic lipids. The Discussion describes TREM2 as a sensor of lipids. In this multiply cited sentence, the paper supports the TREM2 example of an AD-risk gene related to lipids. (LLM, conf=0.90)

  cites [26] Wang, 2015, TREM2 lipid sensing sustains the microglial response in an Alzheimer’s disease model, Cell source
• Partly supported

  The Introduction (page not provided) identifies APOE and TREM2 as AD-risk genes, describes APOE as a lipid transporter, and says TREM2 recognizes lipoproteins. It also describes ABCA1 transferring phospholipids and cholesterol to APOE. The passages from our copy do not establish the claimed lipid-metabolism connection for ABCA7 or CLU, or explicitly identify ABCA1 as an AD-risk gene. (LLM, conf=0.86)

  cites [27] Fitz, 2021, Phospholipids of APOE lipoproteins activate microglia in an isoform-specific manner in preclinical models of Alzheimer’s disease, Nat. Commun. sourceExperimental — accuracy not yet measured
• Partly supported

  The Results sections on LXR signalling and TREM2 link APOE, ABCA1, and TREM2 to cholesterol transport or lipid metabolism (page numbers are not available in our copy). The paper does not establish that the listed genes are Alzheimer’s disease risk genes, and the passages found do not address ABCA7 or CLU. (LLM, conf=0.86)

  cites [28] Bosch-Queralt, 2021, Diet-dependent regulation of TGFβ impairs reparative innate immune responses after demyelination, Nat. Metab. sourceExperimental — accuracy not yet measured
• Partly supported

  The Introduction links TREM2 to lipid metabolism, and the General discussion identifies apolipoprotein E as involved in cholesterol efflux. The passages do not establish that the listed genes are AD-risk genes or address the lipid-metabolism roles of ABCA7, ABCA1, and CLU; this paper studies remyelination rather than AD risk. (LLM, conf=0.86)

  cites [29] Gouna, 2021, TREM2-dependent lipid droplet biogenesis in phagocytes is required for remyelination, J. Exp. Med. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [30] Andreone, 2020, Alzheimer’s-associated PLCγ2 is a signaling node required for both TREM2 function and the inflammatory response in human microglia, Nat. Neurosci. source
• Partly supported

  The Summary and Discussion link TREM2 and APOE to Alzheimer’s disease risk and cholesterol metabolism. The Results also discuss ABCA1 in a cholesterol-efflux experiment, but our copy does not establish it as an AD-risk gene or address ABCA7 or CLU (searched those gene names). (LLM, conf=0.86)

  cites [31] Nugent, 2020, TREM2 Regulates Microglial Cholesterol Metabolism upon Chronic Phagocytic Challenge, Neuron sourceExperimental — accuracy not yet measured

In the paper

“Genome-wide association studies (GWAS) identified many AD risk genes related to the immune response and microglia, including those implicated in phagocytosis, such as CD33 and TREM24,5,6,7,8.”

What the sources say

• ?Not checked — no full text of the sourcecites [4] Bertram, 2008, Genome-wide Association Analysis Reveals Putative Alzheimer’s Disease Susceptibility Loci in Addition to APOE, Am. J. Hum. Genet. source
• Partly supported

  The paper reports a GWAS association for CD33 and describes several AD susceptibility loci as having putative immune functions (Abstract; page not provided). It links ABCA7 to microglia and phagocytosis, but describes CD33 as an endocytic receptor, not specifically a phagocytosis gene. A search of our copy found no mention of TREM2, so this source does not support that example. (LLM, conf=0.90)

  cites [5] Hollingworth, 2011, Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer’s disease, Nat. Genet. sourceExperimental — accuracy not yet measured
• Partly supported

  The GWAS findings (section labeled Abstract; page unavailable) identify several late-onset Alzheimer’s disease risk loci and specifically confirm CD33. Our copy does not identify TREM2 or describe these loci as microglial, immune-response, or phagocytosis genes; searches for those terms found no supporting passage. (LLM, conf=0.88)

  cites [6] Naj, 2011, Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer’s disease, Nat. Genet. sourceExperimental — accuracy not yet measured
• Partly supported

  The introductory passage lists CD33 among Alzheimer’s risk loci identified by GWAS, and the Discussion links TREM2 in microglia to phagocytosis. But the Methods (Study Design) say this paper identified the TREM2 variants through exome or full-genome sequencing; GWAS data were used afterward to confirm an association, not to identify TREM2 as the claim states. (LLM, conf=0.88)

  cites [7] Guerreiro, 2013, TREM2 Variants in Alzheimer’s Disease, N. Engl. J. Med. sourceExperimental — accuracy not yet measured
• Partly supported

  The Discussion reports Alzheimer’s risk variants in several inflammation-related genes, including CD33, and links TREM2 in microglia to phagocytosis. The Results report a genomewide association for a TREM2 variant. Our copy describes CD33 as a myeloid cell-surface receptor but does not establish its role in phagocytosis, so that part of the claim is unsupported. (LLM, conf=0.86)

  cites [8] Jonsson, 2013, Variant of TREM2 Associated with the Risk of Alzheimer’s Disease, N. Engl. J. Med. sourceExperimental — accuracy not yet measured

In the paper

“form a physical barrier believed to restrict plaque propagation13,14”

What the sources say

• Supported

  The Discussion describes microglial processes around plaques as a physical barrier that could restrict fibril polymerization and prevent their outward elongation. This supports the hedged claim that reactive microglia form a barrier believed to restrict plaque propagation. (LLM, conf=0.92)

  cites [13] Condello, 2015, Microglia constitute a barrier that prevents neurotoxic protofibrillar Aβ42 hotspots around plaques, Nat. Commun. source
• Supported

  The Introduction says microglial processes tightly wrap around plaques and form a physical barrier that prevents amyloid fibrils from extending outward. The Results also describe plaque coverage by microglial processes and show that TREM2 deficiency impairs this barrier. Page numbers were not provided in our copy. (LLM, conf=0.94)

  cites [14] Yuan, 2016, TREM2 Haplodeficiency in Mice and Humans Impairs the Microglia Barrier Function Leading to Decreased Amyloid Compaction and Severe Axonal Dystrophy, Neuron source

In the paper

“During early stages of AD, microglia contribute to Αβ clearance15”

What the sources say

• Partly supported

  The ‘Microglial Aβ clearance mechanisms’ subsection says microglia engulf Aβ fibrils by phagocytosis, supporting their contribution to clearance. ‘Modulating innate immunity’ says microglial roles vary by disease stage, but the passages do not establish that this clearance specifically occurs during the early stages of AD. Page numbers are unavailable in our copy. (LLM, conf=0.82)

  cites [15] Heneka, 2015, Neuroinflammation in Alzheimer’s disease, Lancet Neurol. sourceExperimental — accuracy not yet measured

In the paper

“Accumulation of amyloid-beta (Αβ) is a histological hallmark of the AD brain1.”

What the sources say

• Supported

  The Glossary identifies amyloid plaques as extracellular amyloid-beta deposits abundant in the cortex of AD patients. The Conclusions call senile amyloid plaques classical neuropathological lesions that define AD, supporting the claim that amyloid-beta accumulation is a histological hallmark. (LLM, conf=0.94)

  cites [1] Serrano-Pozo, 2011, Neuropathological alterations in Alzheimer disease, Cold Spring Harb. Perspect. Med. source

In the paper

“Single-cell RNA sequencing identified gene signatures characteristic of protective and dysfunctional microglial subpopulations in AD9,10.”

What the sources say

• Partly supported

  The Results describe single-cell RNA sequencing that identified distinct disease-associated microglia (DAM) states and their gene-expression markers in an AD mouse model. The Discussion calls DAM a protective microglial subtype, but the cited passages do not identify a separate dysfunctional microglial subpopulation. Page numbers are unavailable in our copy. (LLM, conf=0.85)

  cites [9] Keren-Shaul, 2017, A Unique Microglia Type Associated with Restricting Development of Alzheimer’s Disease, Cell sourceExperimental — accuracy not yet measured
• Partly supported

  The Results section on AD plaques identifies homeostatic and dysfunctional microglial subsets and reports gene-expression signatures for them. However, STAR*METHODS describes RNA sequencing of 1,000 FACS-sorted microglia, not single-cell RNA sequencing. The paper also does not characterize the homeostatic subset as protective. (LLM, conf=0.90)

  cites [10] Krasemann, 2017, The TREM2-APOE Pathway Drives the Transcriptional Phenotype of Dysfunctional Microglia in Neurodegenerative Diseases, Immunity sourceExperimental — accuracy not yet measured

In the paper

“but sustained inflammation contributes to neurodegeneration12”

What the sources say

• Partly supported

  The Conclusions (page not provided) say increased peripheral inflammation leads to more neurodegeneration in animal models and possibly in Alzheimer disease. That supports a contribution from inflammation, but the review also describes inflammatory responses as potentially protective; it does not establish that sustained inflammation generally causes neurodegeneration. (LLM, conf=0.82)

  cites [12] Wyss-Coray, 2012, Inflammation in Alzheimer disease-A brief review of the basic science and clinical literature, Cold Spring Harb. Perspect. Med. sourceExperimental — accuracy not yet measured

In the paper

“multiple sporadic AD risk variants were identified in microglial transcriptional enhancer regions in humans11”

What the sources say

• Supported

  The paper’s Abstract says that sporadic Alzheimer’s disease risk variants were largely confined to microglial enhancers in human brain cell types. The discussion of fine-mapped variants also identifies multiple AD-risk loci, including BIN1, PICALM, and SORL1, whose variants overlap microglia-specific enhancers. (LLM, conf=0.94)

  cites [11] Nott, 2019, Brain cell type–specific enhancer–promoter interactome maps and disease-risk association, Science source

In the paper

“Increased pro-inflammatory gene expression in response to accumulating Αβ in older AD mice leads to decreased microglial Αβ clearance receptors or Αβ-degrading enzymes, thereby promoting further Αβ accumulation16.”

What the sources say

• Supported

  The Abstract states that pro-inflammatory cytokines produced in response to Aβ deposition downregulate genes involved in Aβ clearance and promote further accumulation. The Discussion reports reduced clearance-receptor and degrading-enzyme expression in aging AD mice, while noting that the mechanism for the enzyme reduction remains uncertain. (LLM, conf=0.88)

  cites [16] Hickman, 2008, Microglial dysfunction and defective β-amyloid clearance pathways in aging alzheimer’s disease mice, J. Neurosci. source

In the paper

“In the AD brain, reactive microglia cluster around Aβ plaques12”

What the sources say

• Supported

  The Microglia section describes dense accumulations of microglia expressing activation markers within and around aggregated Aβ deposits in the AD brain. This directly supports the claim. (LLM, conf=0.94)

  cites [12] Wyss-Coray, 2012, Inflammation in Alzheimer disease-A brief review of the basic science and clinical literature, Cold Spring Harb. Perspect. Med. source

In the paper

“5xFAD mice also develop prominent gliosis, inflammation, neuronal loss, behavioral impairments, and sex-distinct systemic metabolic changes39,38,40.”

What the sources say

• Supported

  The Materials and Methods section describes gliosis, progressive neuronal loss, and cognitive and motor deficiencies in 5XFAD mice; the Discussion reports age-dependent neuroinflammation. The Results report sex-distinct plasma metabolic changes, including lower cholesterol and lipoproteins in males and altered glucose levels in females. The indexed passages provide section labels but no page numbers. (LLM, conf=0.92)

  cites [39] Oblak, 2021, Comprehensive Evaluation of the 5XFAD Mouse Model for Preclinical Testing Applications: A MODEL-AD Study, Front. Aging Neurosci. source
• Partly supported

  The sections on rapid amyloid pathology, neuroinflammation, neuron loss, and spatial memory deficits report gliosis, inflammation, neuron loss, and behavioral impairment in 5XFAD mice (page numbers unavailable). The paper does not report sex-distinct systemic metabolic changes; its sex-related observations concern cerebral amyloid levels and synaptophysin. (LLM, conf=0.90)

  cites [38] Oakley, 2006, Intraneuronal β-amyloid aggregates, neurodegeneration, and neuron loss in transgenic mice with five familial Alzheimer’s disease mutations: Potential factors in amyloid plaque formation, J. Neurosci. sourceExperimental — accuracy not yet measured
• Partly supported

  The Results section reports hippocampal neuronal loss, microglial activation, and severe learning and memory impairments in 5XFAD mice, supporting much of the sentence. Our copy does not establish sex-distinct systemic metabolic changes; the Methods state that only male mice were used for behavioral experiments. Page numbers were not available in the indexed passages. (LLM, conf=0.88)

  cites [40] Merlini, 2019, Fibrinogen Induces Microglia-Mediated Spine Elimination and Cognitive Impairment in an Alzheimer’s Disease Model, Neuron sourceExperimental — accuracy not yet measured

In the paper

“human iPSC-derived microglia were enriched in LDs in a chimeric mouse model of AD37”

What the sources say

• Supported

  The Findings section reports that human iPSC-derived microglia accumulated lipid droplets in the chimeric AD mouse model. It specifies that accumulation was particularly evident in plaque-associated, disease-associated microglia; the citing sentence is a broad summary of that result. (LLM, conf=0.92)

  cites [37] Claes, 2021, Plaque-associated human microglia accumulate lipid droplets in a chimeric model of Alzheimer’s disease, Mol. Neurodegener. source

In the paper

“Inflammatory triggers like lipopolysaccharide (LPS)35,19, fatty acids36, and aging20 promote LD accumulation in primary microglial cells and cell lines.”

What the sources say

• ?Not checked — no full text of the sourcecites [35] Khatchadourian, 2012, Dynamics and regulation of lipid droplet formation in lipopolysaccharide (LPS)-stimulated microglia, Biochim. Biophys. Acta source
• Partly supported

  The Results (Remodeling of lipid bodies; page unavailable) show that LPS increased lipid vacuoles in the N9 microglial cell line, but distinguish those vacuoles from lipid droplets, which were rare under both control and LPS-only conditions. This source therefore supports LPS-related lipid-body accumulation, not the more specific claim that LPS alone promotes lipid-droplet accumulation. The sentence assigns fatty acids and aging to other citations. (LLM, conf=0.88)

  cites [19] Tremblay, 2016, Remodeling of lipid bodies by docosahexaenoic acid in activated microglial cells, J. Neuroinflammation sourceExperimental — accuracy not yet measured
• Supported

  The citation to this paper is attached to “fatty acids,” not to LPS or aging. The Discussion reports that unsaturated fatty acids increased lipid-droplet formation in microglial cells, and Materials and Methods §4.1 identifies the cells as the BV2 microglial cell line. No page numbers are available in our copy. (LLM, conf=0.92)

  cites [36] Urso, 2021, Palmitic acid lipotoxicity in microglia cells is ameliorated by unsaturated fatty acids, Int. J. Mol. Sci. source
• Supported

  Citation 20 is attached to the aging part of the sentence. The Results section, “Microglia accumulate lipid droplets in the aging brain” (page unavailable), reports substantially more lipid-droplet-containing microglia in aged than young mice. The Results section, “LDAM have phagocytosis deficits” (page unavailable), also reports that aged plasma induced lipid droplets in the BV2 microglial cell line. (LLM, conf=0.88)

  cites [20] Marschallinger, 2020, Lipid-droplet-accumulating microglia represent a dysfunctional and proinflammatory state in the aging brain, Nat. Neurosci. source

In the paper

“which progressively accumulates extensive Aβ plaques (especially in the subiculum and deep cortical layers) starting around 2–3 months of age”

What the sources say

• Supported

  The paper’s opening summary states that amyloid deposition begins at 2 months and reaches a very large burden, especially in the subiculum and deep cortical layers. The section on rapid Aβ42 accumulation adds that plaques first appear in those regions in young mice and spread as the mice age. This supports the cited paraphrase’s timing, location, and progressive accumulation. (LLM, conf=0.94)

  cites [38] Oakley, 2006, Intraneuronal β-amyloid aggregates, neurodegeneration, and neuron loss in transgenic mice with five familial Alzheimer’s disease mutations: Potential factors in amyloid plaque formation, J. Neurosci. source

In the paper

“The DGAT2 enzyme is evolutionarily conserved across eukaryotes and has the predominant and ancient function of mediating TG synthesis from fatty acids50.”

What the sources say

• Supported

  The Discussion describes DGAT2 as evolutionarily conserved across eukaryotes as a major TG-synthesis enzyme. It also describes TG synthesis from de novo-synthesized fatty acids as DGAT2’s more ancient function; the citing sentence is a close paraphrase, though it omits the de novo qualifier. (LLM, conf=0.92)

  cites [50] Chitraju, 2019, The triglyceride synthesis enzymes DGAT1 and DGAT2 have distinct and overlapping functions in adipocytes, J. Lipid Res. source

In the paper

“DGAT2 is localized around LDs where it is required for TG synthesis51,52,53.”

What the sources say

• Supported

  The Results sections “Specific Isoenzymes of De Novo TG Synthesis Localize to Mature LDs” and “LD-Localized TG Synthesis Enzymes Are Required for LD Growth” identify DGAT2 as a TG-synthesis enzyme that relocalizes to lipid droplets. The latter section reports that depleting DGAT2 markedly reduces the large-droplet population, supporting its role in local TG synthesis and droplet growth. Page numbers are unavailable in our copy. (LLM, conf=0.89)

  cites [51] Wilfling, 2013, Triacylglycerol synthesis enzymes mediate lipid droplet growth by relocalizing from the ER to lipid droplets, Dev. Cell source
• ?Not checked — no full text of the sourcecites [52] Kuerschner, 2008, Imaging of lipid biosynthesis: How a neutral lipid enters lipid droplets, Traffic source
• ?Not checked — no full text of the sourcecites [53] Stone, 2009, The endoplasmic reticulum enzyme DGAT2 is found in mitochondria-associated membranes and has a mitochondrial targeting signal that promotes its association with mitochondria, J. Biol. Chem. source

In the paper

“with female cells exhibiting higher pro-inflammatory responses compared to age-matched male cells.67,68”

What the sources say

• Partly supported

  The Discussion reports a stronger pro-inflammatory response to LPS in aged female than aged male mouse brains, and the Results identify higher levels of particular inflammatory transcripts in aged females. The claim omits the aged-mouse and acute LPS-challenge conditions and presents a brain-level finding as a general property of female microglial cells; the Discussion also describes adult male microglia as more poised to inflammatory reactions. (LLM, conf=0.87)

  cites [67] Murtaj, 2019, Age and Sex Influence the Neuro-inflammatory Response to a Peripheral Acute LPS Challenge, Front. Aging Neurosci. sourceExperimental — accuracy not yet measured
• Partly supported

  The Subjects section specifies age-matched male and female rats, and Experiment 3b reports a greater pro-inflammatory response in female than male vlPAG after LPS challenge. But cytokine mRNA was measured in vlPAG tissue, not isolated microglia; the paper does not establish that female microglial cells themselves produced the higher response. It also limits the finding to this brain region and immune-challenge condition. (LLM, conf=0.85)

  cites [68] Doyle, 2017, Sex differences in microglia activity within the periaqueductal gray of the rat: A potential mechanism driving the dimorphic effects of morphine, J. Neurosci. sourceExperimental — accuracy not yet measured

In the paper

“Sex differences in microglia have been reported in both rodents and humans66”

What the sources say

• Partly supported

  The Abstract and the section on microglial morphology and numbers through development report sex differences in rodent microglia. The review focuses on rodents; the passages found do not report corresponding differences in human microglia, so the human part of the claim is unsupported by this paper. (LLM, conf=0.87)

  cites [66] Han, 2021, Uncovering sex differences of rodent microglia, J. Neuroinflammation sourceExperimental — accuracy not yet measured

In the paper

“Microglia engulf and degrade Aβ74,75”

What the sources say

• Partly supported

  The Results (page unavailable) show that microglia phagocytose oligomeric and protofibrillar Aβ, supporting “engulf.” The same passage says this material “may be targeted for degradation” because it is found in phagolysosomes; it does not establish degradation as a fact. The Discussion also reports that microglia could not remove fibrillar amyloid from preexisting plaques in vivo. (LLM, conf=0.88)

  cites [74] Liu, 2010, CX3CR1 in microglia regulates brain amyloid deposition through selective protofibrillar amyloid-β phagocytosis, J. Neurosci. sourceExperimental — accuracy not yet measured
• Supported

  The Introduction states that microglia take up soluble Aβ and subsequently degrade it. The Abstract likewise reports internalization followed by degradation in late endolysosomal compartments; the paper distinguishes this soluble-Aβ pathway from uptake of fibrillar Aβ. (LLM, conf=0.93)

  cites [75] Mandrekar, 2009, Microglia mediate the clearance of soluble aβ through fluid phase macropinocytosis, J. Neurosci. source

In the paper

“their phagocytic capacity declines with aging, chronic exposure to Αβ, and during sustained inflammation in the AD brain76,16,17.”

What the sources say

• Partly supported

  The Discussion (page unavailable) reports a 2- to 4-fold age-related decrease in Aβ internalization by microglia from aged mice, supporting the aging portion of the claim. The paper does not show that chronic Aβ exposure or sustained inflammation in the AD brain causes a decline in phagocytic capacity; it discusses AD as a possible implication of its age-related findings. (LLM, conf=0.90)

  cites [76] Njie, 2012, Ex vivo cultures of microglia from young and aged rodent brain reveal age-related changes in microglial function, Neurobiol. Aging sourceExperimental — accuracy not yet measured
• Partly supported

  The Discussion reports declining Aβ-clearing ability as PS1-APP mice age and AD-like pathology progresses. The Results show reduced Aβ uptake after TNFα treatment and increased inflammatory cytokines in older mice with continued Aβ deposition. The paper does not establish chronic Aβ exposure as a separate cause of declining phagocytosis or demonstrate the claimed decline in human AD brains; its direct evidence is from mice and cultured mouse microglia. Page numbers are unavailable in our copy. (LLM, conf=0.84)

  cites [16] Hickman, 2008, Microglial dysfunction and defective β-amyloid clearance pathways in aging alzheimer’s disease mice, J. Neurosci. sourceExperimental — accuracy not yet measured
• Partly supported

  The Results section reports reduced microglial phagocytosis where Aβ plaques were present in Alzheimer-like mice, but normal capacity in plaque-free regions, including as the mice aged. The Discussion proposes sustained inflammation as a possible explanation rather than establishing it as a cause. The paper therefore supports plaque-associated decline, not the full claim that aging, chronic Aβ exposure, and sustained inflammation each cause decline in the AD brain. (LLM, conf=0.88)

  cites [17] Krabbe, 2013, Functional Impairment of Microglia Coincides with Beta-Amyloid Deposition in Mice with Alzheimer-Like Pathology, PLoS One sourceExperimental — accuracy not yet measured

In the paper

“which are the sites of the earliest atrophy seen during AD pathogenesis.65”

What the sources say

• Partly supported

  The Abstract Conclusions and Discussion identify the presubiculum and subiculum as sites of prevalent atrophy from early AD phases in human patients. The study examined people with MCI or AD and healthy controls, not 5xFAD mice, so it does not support the mouse portion of the claim. (LLM, conf=0.88)

  cites [65] Carlesimo, 2015, Atrophy of presubiculum and subiculum is the earliest hippocampal anatomical marker of Alzheimer’s disease, Alzheimers. Dement. (Amst) sourceExperimental — accuracy not yet measured

In the paper

“Previous studies have established APP as a marker of axonal degeneration54,55 and demonstrated its accumulation in presynaptic terminals, indicative of dystrophic neurons surrounding amyloid plaques.56”

What the sources say

• ?Not checked — no full text of the sourcecites [54] Mabrouk, 2023, Most dystrophic neurites in the common 5xFAD Alzheimer mouse model originate from axon terminals, Neurobiol. Dis. source
• Partly supported

  The Discussion reports that CSF APP-derived peptides may serve as neurodegeneration biomarkers in FTLD, supporting the marker idea in a narrower form. It does not establish APP itself as a marker specifically of axonal degeneration. The separate claim about accumulation near amyloid plaques is attached to citation 56, not to this source. (LLM, conf=0.85)

  cites [55] Illán-Gala, 2019, APP-derived peptides reflect neurodegeneration in frontotemporal dementia, Ann. Clin. Transl. Neurol. sourceExperimental — accuracy not yet measured
• Partly supported

  The Results report APP accumulations around amyloid plaques enriched in presynaptic proteins, and the study conclusions describe presynaptic APP within dystrophic axons (page numbers unavailable). However, the paper places the accumulations at axon terminals only presumptively; it does not demonstrate that they are in presynaptic terminals. The axonal-degeneration marker claim is attached to citations 54 and 55, not this citation. (LLM, conf=0.85)

  cites [56] Jordà-Siquier, 2022, APP accumulates with presynaptic proteins around amyloid plaques: A role for presynaptic mechanisms in Alzheimer’s disease?, Alzheimers Dement. sourceExperimental — accuracy not yet measured

In the paper

“Injured neurons and oligodendrocytes have a low capacity for consuming FFAs and sequestering them into LDs61, making them more vulnerable to lipid-induced cytotoxicity in chronic inflammation62,63.”

What the sources say

• ?Not checked — no full text of the sourcecites [61] Schönfeld, 2013, Why does brain metabolism not favor burning of fatty acids to provide energy? Reflections on disadvantages of the use of free fatty acids as fuel for brain, J. Cereb. Blood Flow Metab. source
• Partly supported

  Section 1, “Lipid peroxidation and neurodegeneration” (page unavailable), says lipid peroxidation damages neuronal membranes and produces compounds that cause cellular damage. It does not establish the claimed vulnerability of oligodendrocytes or place that damage in chronic inflammation. The separate claim about FFA consumption and lipid-droplet sequestration is attached to citation 61, not to this source. (LLM, conf=0.83)

  cites [62] Sultana, 2013, Lipid peroxidation triggers neurodegeneration: A redox proteomics view into the Alzheimer disease brain, Free Radic. Biol. Med. sourceExperimental — accuracy not yet measured
• Partly supported

  The Introduction (p. 2) says neurons do not typically make lipid droplets and have low capacity to consume fatty acids in mitochondria, supporting the neuron portion of the clause cited to this paper. The discussion of oligodendrocytes in “Astrocytes are equipped with the machinery to neutralize ROS” (p. 11) concerns oxidative-stress genes; it does not establish that oligodendrocytes share those limitations. The chronic-inflammation clause carries separate citations. (LLM, conf=0.89)

  cites [63] Ioannou, 2019, Neuron-Astrocyte Metabolic Coupling Protects against Activity-Induced Fatty Acid Toxicity, Cell sourceExperimental — accuracy not yet measured

In the paper

“female microglia upregulate genes related to metabolic activities like glycolysis and oxidative metabolism, which become more pronounced with aging.69”

What the sources say

• Supported

  The Discussion reports increased expression of genes involved in glycolysis and oxidative phosphorylation in aged female microglia compared with males. The Results section also identifies glycolytic and mitochondrial genes with increased expression in female microglia with aging. The claim concerns gene expression, not a measured increase in metabolic activity. (LLM, conf=0.93)

  cites [69] Cleland, 2024, Altered metabolism and DAM-signatures in female brains and microglia with aging, Brain Res. source

In the paper

“Subclusters of lipid-associated microglia were also enriched in women compared to men,72”

What the sources say

• ?Could not verify

  The high-resolution cell atlas section (page unavailable) identifies Mic.12 and Mic.13 as lipid-associated microglial subpopulations. The sections on AD-related traits and disease-associated microglia discuss their proportions in relation to pathology and diagnosis, but do not report enrichment in women versus men. Searches for female/male enrichment and sex differences found no passage addressing that comparison. (LLM, conf=0.73)

  cites [72] Green, 2023, Cellular dynamics across aged human brains uncover a multicellular cascade leading to Alzheimer’s disease, Alzheimers Dement. sourceExperimental — accuracy not yet measured

In the paper

“Late-onset AD, (~95% of AD cases), is associated with impaired Αβ clearance73.”

What the sources say

• Partly supported

  The paper’s findings passage reports that late-onset AD is associated with impaired clearance of Aβ40 and Aβ42. It describes late-onset AD as far more common than rare genetic cases, but does not give the claimed figure of approximately 95% of AD cases (no page number is available in our copy). (LLM, conf=0.87)

  cites [73] Mawuenyega, 2010, Decreased clearance of CNS β-amyloid in Alzheimer’s disease, Science sourceExperimental — accuracy not yet measured

In the paper

“Reactive astrocytes secrete long-chain saturated FFAs that kill injured neurons and oligodendrocytes in vitro and in vivo41.”

What the sources say

• Partly supported

  The Discussion reports that reactive astrocytes drive neuronal and mature oligodendrocyte death through delivery of FFAs and very-long-chain phosphatidylcholines. Extended Data Figure 7 shows saturated FFA toxicity to cultured oligodendrocytes, while the optic-nerve-crush results concern injured retinal neurons in vivo. The paper does not establish oligodendrocyte death in vivo, and it describes the in-vivo contribution of FFAs and phosphatidylcholines as partial rather than attributing it to FFAs alone. (LLM, conf=0.88)

  cites [41] Guttenplan, 2021, Neurotoxic reactive astrocytes induce cell death via saturated lipids, Nature sourceExperimental — accuracy not yet measured

In the paper

“restoration of microglial phagocytosis improved cognitive function in aged mice and promoted a homeostatic microglial transcriptional signature78.”

What the sources say

• Supported

  In the section “Long-term CD22 blockade restores microglial homeostasis and improves cognitive function in aged mice” (page not provided), anti-CD22 treatment upregulated homeostatic microglial genes and downregulated activated and disease-associated genes. The same section reports improved learning and memory in aged mice after CNS-specific CD22 blockade, the intervention used to restore microglial phagocytosis. (LLM, conf=0.93)

  cites [78] Pluvinage, 2019, CD22 blockade restores homeostatic microglial phagocytosis in ageing brains, Nature source

In the paper

“Genetic deletion of any of these receptors in mouse models of AD resulted in less compact/more diffuse plaques, and increased neuritic dystrophy around Αβ deposits14,79.”

What the sources say

• Supported

  The Results sections on plaque compaction and axonal dystrophy report that Trem2-deficient AD-like mice had more diffuse, less compact plaques and greater axonal dystrophy than wild-type mice. This supports the claim as applied to TREM2, the receptor studied by this source; the copy does not establish the same result for every receptor that might be meant by the citing sentence. (LLM, conf=0.91)

  cites [14] Yuan, 2016, TREM2 Haplodeficiency in Mice and Humans Impairs the Microglia Barrier Function Leading to Decreased Amyloid Compaction and Severe Axonal Dystrophy, Neuron source
• Partly supported

  The Results (“TAM-dependent phagocytosis and shaping of plaques”; page unavailable) report more diffuse plaques and increased markers of dystrophic neuronal membranes after combined Axl and Mertk deletion in APP/PS1 mice. But the paper does not show these outcomes after deletion of any one receptor: in “Dense-core plaque burden in the absence of TAM signaling,” Mertk deletion largely reproduces the reduction in dense-core plaques, whereas Axl deletion does not reduce cortical plaque burden. (LLM, conf=0.90)

  cites [79] Huang, 2021, Microglia use TAM receptors to detect and engulf amyloid β plaques, Nat. Immunol. sourceExperimental — accuracy not yet measured

In the paper

“the phagocytic function of macrophages was found dependent on FFAs generated upon degradation of LDs, suggesting that LD accumulation somehow limits the phagocytic capacity of tissue-resident macrophages81.”

What the sources say

• Partly supported

  The Introduction and Discussion report that reduced release of fatty acids from lipid-droplet triglycerides impairs phagocytosis, and suggest that accumulated droplets may also contribute. But the Experimental Procedures describe thioglycollate-elicited mouse peritoneal macrophages and bone-marrow-derived macrophages; the paper does not establish the proposed limitation across tissue-resident macrophages generally. (LLM, conf=0.85)

  cites [81] Chandak, 2010, Efficient phagocytosis requires triacylglycerol hydrolysis by adipose triglyceride lipase, J. Biol. Chem. sourceExperimental — accuracy not yet measured

In the paper

“AβpH is a pH-sensitive fluorophore conjugate of Aβ1–42 peptide that is generated within our laboratory and has been thoroughly characterized in vitro in primary cell culture as well as in vivo experiments in our previous study.47”

What the sources say

• Supported

  The Introduction (page not specified) says the authors developed AβpH, a pH-dependent fluorescent conjugate of human Aβ1–42, and characterized its uptake in vitro and in vivo. The Discussion (page not specified) specifically reports testing it in primary microglial and astrocyte cultures and in live mice. (LLM, conf=0.94)

  cites [47] Prakash, 2021, Monitoring phagocytic uptake of amyloid β into glial cell lysosomes in real time, Chem. Sci. source

In the paper

“Further, pharmacological inhibition of DGAT2 has consistently shown efficacy in pre-clinical studies demonstrating reduced TG synthesis accompanied by reduced expression of genes essential for de novo lipogenesis.85”

What the sources say

• Supported

  The Abstract states that DGAT2 inhibition has consistent efficacy in nonclinical studies, with reduced triglyceride synthesis accompanied by reduced expression of genes essential for de novo lipogenesis. The “Are Functionally Distinct” section also reports reductions in triglycerides and hepatic lipogenic-gene mRNA after DGAT2 inhibition. (LLM, conf=0.94)

  cites [85] Amin, 2023, Inhibition of Diacylglycerol Acyltransferase 2 Versus Diacylglycerol Acyltransferase 1: Potential Therapeutic Implications of Pharmacology, Clin. Ther. source

In the paper

“Prior studies proposed that these cells compact amyloid plaques through receptors implicated in phagocytosis such as TREM214, (expressed on myeloid cells and associated to increased AD risk)14,8, AXL, and MER79.”

What the sources say

• Supported

  The Results section reports that TREM2 is enriched in microglial processes contacting plaques and that those processes wrap amyloid fibrils. The Discussion states that the microglial barrier increases plaque compaction and that TREM2 deficiency weakens the barrier. The citation to this paper attaches to TREM2, not AXL or MER. (LLM, conf=0.91)

  cites [14] Yuan, 2016, TREM2 Haplodeficiency in Mice and Humans Impairs the Microglia Barrier Function Leading to Decreased Amyloid Compaction and Severe Axonal Dystrophy, Neuron source
• Partly supported

  The Discussion (page unavailable in our copy) says TREM2 is expressed on microglia and links its expression to amyloid phagocytosis near plaques. It does not say that TREM2 enables microglia to compact plaques. The AXL and MER portion carries a different citation and is not attributed to this source. (LLM, conf=0.88)

  cites [8] Jonsson, 2013, Variant of TREM2 Associated with the Risk of Alzheimer’s Disease, N. Engl. J. Med. sourceExperimental — accuracy not yet measured
• Supported

  The citation to this paper follows AXL and MER, so it supports that part of the sentence. The Discussion (page unavailable) proposes that phagocytic microglia construct dense-core plaques from loosely organized amyloid material and identifies TAM receptors as key to that process; the Results further attribute most of the phagocytosis-dependent construction to Mer. (LLM, conf=0.92)

  cites [79] Huang, 2021, Microglia use TAM receptors to detect and engulf amyloid β plaques, Nat. Immunol. source

In the paper

“The aggregated states of the Aβ1–42 peptides have been thoroughly characterized using atomic force microscopy and western blotting in our previous papers.100,47”

What the sources say

• Supported

  The Experimental Design and Expected Results and Discussion sections report characterizing recombinant Aβ(M1-42) and synthetic Aβ42 by western blotting and atomic force microscopy. They describe monomeric and oligomeric bands, oligomer sizes, and fibrils. Page numbers are not provided in the supplied copy. (LLM, conf=0.90)

  cites [100] Prakash, 2019, Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid beta 1–42, Methods Protoc. source
• Partly supported

  The Results section (page unavailable) reports AFM characterization of Aβ1–42 oligomers, and the Methods section says the AFM analysis followed previously published protocols. The passages do not establish that previous papers thoroughly characterized the peptides’ aggregated states using both AFM and western blotting; western blotting is not documented in the retrieved passages. (LLM, conf=0.85)

  cites [47] Prakash, 2021, Monitoring phagocytic uptake of amyloid β into glial cell lysosomes in real time, Chem. Sci. sourceExperimental — accuracy not yet measured

In the paper

“Pharmacologically targeting DGAT2 improved microglial uptake of Aβ and reduced plaque load and neuronal damage in 5xFAD mice.”

• Also stated in: § The DGAT2 pathway is required for Aβ-induced lipid droplet formation in AD microglia, and its inhibition rescues microglial phagocytic impairment and reduces plaque load in AD · plain

  “LD+ 5xFAD microglia showed a significant increase (1.41-fold) in AβpH uptake with D2i”

• Also stated in: § The DGAT2 pathway is required for Aβ-induced lipid droplet formation in AD microglia, and its inhibition rescues microglial phagocytic impairment and reduces plaque load in AD · plain

  “animals that received the DGAT2 degrader over a period of 1 week showed a drastic reduction in plaque burden by ~51% in the subicular hippocampal region compared to age-matched vehicle-treated animals”

In the paper

“We found very few secretory lipids differentially regulated with Aβ treatment –none at 1 hour, five at 12 hours, and one at 24 hours, respectively”

In the paper

“In contrast, the male lipidome showed less variability (Fig. S1f), in agreement with the more limited variation in LD content in male microglia”

In the paper

“In the subiculum, plaque-proximal microglia demonstrated an amoeboid morphology, while plaque-distant cells typically had smaller cell bodies and longer processes”

In the paper

“Metabolites like fructose 6-phosphate and lactose were downregulated in 5xFAD microglia compared to WT cells, affecting several metabolic pathways such as the citrate TCA cycle, glutamine and glutamate metabolism, arginine biosynthesis, etc.”

In the paper

“LD+ microglia were predominantly near amyloid plaques, and their numbers declined with distance from them”

In the paper

“we found that FFAs were indeed increased at 1 hour and reduced at 24 hours”

In the paper

“FFAs were the most differentially regulated lipid class, with very long-chain saturated FFAs, C20:0, C22:0, and C19:0 being the most upregulated lipids at 1 hour of Aβ exposure”

In the paper

“In contrast, cells with prolonged Aβ exposure (24 hours) did not maintain their FFA repertoire and instead transitioned to TGs being the most differentially-regulated lipid class, with TG(52:3), TG(54:3), and TG(52:2) being the most upregulated”

In the paper

“At 12 hours of Aβ treatment, in addition to FFAs, cholesteryl esters (CEs) were the second most differentially regulated lipid class in microglia, with very long chain CEs 20:2, 24:1, and 16:3 being the top upregulated CEs”

In the paper

“human LD+ microglia closer to plaques (0–10μm) contained larger LDs, and their total LD load also decreased progressively with distance from the nearest plaque”

In the paper

“We found these distinct LD-laden microglia throughout the brain, but more prominently in the hippocampal subicular regions of 5xFAD mice and in hippocampi from individuals with AD”

In the paper

“Indeed, LD-laden microglia were closely associated with Aβ plaques and exhibited shorter processes and larger cell bodies in both 5xFAD mouse and human AD brains.”

In the paper

“Although overall LD content was increased in both male and female microglia, female cells showed higher abundance of LD load compared to age-matched male cells.”

In the paper

“there was a significant reduction in Aβ-induced LDs with D2i treatment in WT microglia, thereby confirming that Aβ-induced LD formation requires the DGAT2 pathway”

In the paper

“Both WT and 5xFAD microglia showed a significant decrease in LDs upon D2i treatment in vitro (by 51% and 57%, respectively”

In the paper

“Our data shows that amyloid exposure directly increased overall LD load in all microglia in vitro and in vivo, but with sex-dependent variability.”

In the paper

“LD+ 5xFAD microglia showed a significant increase (1.41-fold) in AβpH uptake with D2i, which was similar to LD+ WT microglia in the presence of the inhibitor”

In the paper

“We found that plaque–associated microglia progressively accumulated more LDs, and that cells with high LD content were less capable of Aβ phagocytosis.”

In the paper

“For example, we found that administration of DGAT2 degrader directly inside the brain drastically and rapidly reduced LDs, particularly from plaque-associated microglia but without eliminating LDs completely.”

In the paper

“Here, we identified one such druggable molecule that regulates LD accumulation in microglia while also directly impacting their function and the health of nearby neurons.”

In the paper

“Disrupting DGAT2 alone proved sufficient to not only reduce microglial LDs but also restore their phagocytic efficiency”

In the paper

“We thus developed a new DGAT2 protein degrader that not only reduced LD load in vivo in 11–24-month-old 5xFAD mice but also produced a profound reduction of amyloid load (51%) and neurite dystrophy (47%), despite its very brief treatment duration (only 1 week).”

In the paper

“their dysregulation has been linked to neurodegenerative disorders, including AD24”

What the sources say

• ?Not checked — no full text of the sourcecites [24] Wong, 2017, Dysregulation of lipids in Alzheimer’s disease and their role as potential biomarkers, Alzheimers Dement. source

In the paper

“These findings identify a lipid-mediated mechanism underlying microglial dysfunction that could become a therapeutic target for AD.”

In the paper

“Cellular lipids regulate functions like migration and phagocytosis22”

What the sources say

• ?Not checked — no full text of the sourcecites [22] Bourre, 2009, Brain lipids and ageing source

In the paper

“Since TGs constitute the major neutral lipid core of LDs and are integral to their structure and function”

In the paper

“The diacylglycerol O-acyltransferase (DGAT) enzymes catalyze the final rate-determining step in the biosynthesis of TGs.”

In the paper

“The conversion of FFAs to TGs can occur via two major pathways involving several intermediates: 1) the glycerol phosphatase pathway or 2) the monoacylglycerol pathway”

What the sources say

• ?Not checked — no full text of the sourcecites [49] Yen, 2008, Thematic review series: Glycerolipids. DGAT enzymes and triacylglycerol biosynthesis, J. Lipid Res. source

In the paper

“Taken together, these findings demonstrate that degrading DGAT2 profoundly reduced LD content and mitigated neuritic dystrophy as well as amyloid pathology even in chronically inflamed 11–24-month-old 5xFAD mice”

In the paper

“These results suggest a possible LD saturation mechanism, where DGAT2-mediated microglial LD formation occurs with prolonged amyloid exposure, but after a certain point additional Aβ exposure seems insufficient to drive further LD accumulation in microglia.”

In the paper

“Phagocytosis is a major innate immune mechanism contributing to Αβ clearance, and its failure favors Αβ accumulation in the brain.”

In the paper

“identified the DGAT2 pathway as a target for therapeutic intervention to reduce phagocytic impairment of microglia and promote amyloid clearance or limit amyloid accumulation and associated neuronal dystrophy in the AD brain”

In the paper

“We also did not interrogate how molecules in addition to Aβ may promote LD formation, or exactly how FFAs increase in microglia in response to Aβ exposure, or what other microglial functions may be affected by LD formation or reduction.”

In the paper

“Similarly, inhibiting acyl-coA synthetase long-chain 1 (ACSL1), is successful in reducing LDs, but this enzyme converts FFAs to acyl-CoA, which is a key step in ATP generation that cells use as an energy source; therefore, inhibiting ACSL1 leads to lipotoxicity through toxic FFA accumulation and metabolic failure due to impaired energy production.”

In the paper

“As such, combination therapy with the DGAT2 inhibitor Ervogastat and Clesacostat, an inhibitor of Acetyl-CoA Carboxylase (ACC, also a downstream rate-limiting enzyme in de novo lipogenesis) was granted fast track designation by the FDA for the treatment of non-alcoholic steatohepatitis (NASH) with liver fibrosis, based on its favorable safety and tolerability profile in a Phase2a clinical trial.86”

What the sources say

• ?Not checked — no full text of the sourcecites [86] Calle, 2021, ACC inhibitor alone or co-administered with a DGAT2 inhibitor in patients with non-alcoholic fatty liver disease: two parallel, placebo-controlled, randomized phase 2a trials, Nat. Med. source

In the paper

“The specificity of the IBA1 and PLIN2 staining was ensured with the secondary antibody control images shown in Fig. S2g.”

In the paper

“All experiments involving mice were performed in accordance with the Purdue University’s Institutional Animal Care and Use Committee (IACUC) guidelines under application number 1812001834.”

In the paper

“The experimental blank that was done with the injection media was modeled as an ‘intercept’ sample in the analysis to make certain that comparisons were significant with respect to the blank.”

In the paper

“Data collection was randomized for all experiments and experimenters were blinded for imaging and data analyses.”

In the paper

“Reactions were run in duplicate.”

In the paper

“NS control samples were obtained from cases without a neurological or psychiatric diagnosis, and no chronic systemic inflammatory or infectious condition.”

In the paper

“Plaque–associated microglia have direct access to remove aggregated amyloid through phagocytosis.”

In the paper

“Our study thus provides proof-of-principle that disrupting DGAT2 can be a highly effective strategy for promoting a protective role of microglia in AD, and possibly in other neurodegenerative diseases with excessive protein aggregation and LD deposition.”

In the paper

“Data collection was randomized for all experiments and experimenters were blinded for imaging and data analyses.”

In the paper

“Importantly, inhibiting DGAT2 restored phagocytosis in 5xFAD microglia ex-vivo, suggesting that phagocytic dysfunction is a consequence, not a cause of chronic LD accumulation.”

In the paper

“highlight DGAT2 as a promising target for AD compared to other LD-reducing molecules, possibly without introducing systemic side-effects.”

In the paper

“This size exclusion of speckles and artifacts also ensured that only true LD particles were selected for visualization and quantification in the PLIN2 channel.”

In the paper

“Therefore, we identified DGAT2 as a promising target to restore microglial phagocytosis, and thereby decrease amyloid deposition, and protect neurons, possibly without requiring a protracted treatment regimen, and perhaps even in patients with advanced pathology.”

In the paper

“This study did not directly test all possible treatment regiments or administration methods to degrade DGAT2 in vivo”

In the paper

“After all, LDs are important organelles that cells use for energy storage and to buffer excess lipids, which can protect them against lipotoxicity, especially in the context of inflammation.”

In the paper

“Acute exposure of primary microglia to Aβ increased their inflammatory cytokine secretion and phagocytic performance, while chronic exposure reduced phagocytosis and induced immune tolerance, as well as a metabolic shift from oxidative phosphorylation to glycolysis77.”

What the sources say

• ?Not checked — no full text of the sourcecites [77] Baik, 2019, A Breakdown in Metabolic Reprogramming Causes Microglia Dysfunction in Alzheimer’s Disease, Cell Metab. source

In the paper

“For example, liver X receptor (LXR) agonists reduce LD accumulation through enhanced cholesterol efflux and exhibit anti-inflammatory properties, but their concurrent promotion of lipogenesis also leads to adverse effects such as hepatic steatosis and hyperlipidemia.82,83”

What the sources say

• ?Not checked — no full text of the sourcecites [82] Kirchgessner, 2016, Beneficial and Adverse Effects of an LXR Agonist on Human Lipid and Lipoprotein Metabolism and Circulating Neutrophils, Cell Metab. source
• ?Not checked — no full text of the sourcecites [83] Hua, 2023, Liver X receptors: From pharmacology to nanoparticle-based drug delivery, Eur. J. Pharmacol. source