ACSS2-dependent histone acetylation improves cognition in mouse model of Alzheimer's disease

Acetyl-CoA synthetase 2 alleviates brain injury following cardiac arrest by promoting autophagy in brain microvascular endothelial cells

INTRODUCTION

Brain injury is a common sequela following cardiac arrest (CA), with up to 70% of hospitalized patients dying from it. Brain microvascular endothelial cells (BMVECs) play a crucial role in post-cardiac arrest brain injury (PCABI). However, the effects and mechanisms of targeting BMVEC energy metabolism to mitigate brain injury remain unclear.

METHODS

We established a mouse model of cardiac arrest by injecting potassium chloride into the right internal jugular vein. Mass spectrometry detected targeted changes in short-chain fatty acids and energy metabolism metabolites in the CA/CPR group compared to the sham group. Mice with overexpressed ACSS2 in BMVECs were created using an AAV-BR1 vector, and ACSS2 knockout mice were generated using the CRE-LOXP system. The oxygen glucose deprivation/re-oxygenation (OGD/R) model was established to investigate the role and mechanisms of ACSS2 in endothelial cells in vitro.

RESULTS

Metabolomics analysis revealed disrupted cerebral energy metabolism post-CA/CPR, with decreased acetyl-CoA and amino acids. Overexpression of ACSS2 in BMVECs increased acetyl-CoA levels and improved neurological function. Vascular endothelial cell-specific ACSS2 knockout mice exhibited reduced aortic sprouting in vitro. Overexpression of ACSS2 improved endothelial dysfunction following oxygen glucose deprivation/re-oxygenation (OGD/R) and influenced autophagy by interacting with transcription factor EB (TFEB) and modulating the AMP-activated protein kinase α (AMPKα) pathway.

CONCLUSION

Our study shows that ACSS2 modulates the biological functions of BMVECs by promoting autophagy. Enhancing energy metabolism via ACSS2 may target PCABI treatment development.

Senkyunolide A interrupts TRAF6-HDAC3 interaction to epigenetically suppress c-MYC and attenuate cholestatic liver injury

Introduction Cholestatic liver diseases are highly prevalent and lack effective treatment, ultimately progressing to end-stage liver diseases. Our recent study indicates that the interplay between c-MYC and lncRNA H19 exacerbates the ductular reaction during cholestasis.

OBJECTIVE

This study aims to unveil the underlying mechanisms of the protective effects of senkyunolide A (SenA) on cholangiocyte overproliferation in cholestatic liver diseases.

METHODS

Through comprehensive characterization using RNA sequencing, CHIP analysis, protein truncation, amino acid mutation or deletion, and the development of SenA derivatives, we explored the effects and mechanisms of SenA in vivo in bile duct ligation mice and in vitro in primary cholangiocytes.

RESULTS

We demonstrated that SenA effectively mitigates cholangiocyte hyperproliferation by epigenetically suppressing c-MYC expression and disrupting the downstream H19, Let-7a and Lin28a. Mechanically, we identified a potential interaction between the carbonyl group in SenA and Arg483 in TRAF6, disrupting the TRAF6-HDAC3 complex. This dissociation facilitates the binding of HDAC3 to the MYC promoter region, resulting in enhanced histone deacetylation and transcriptional suppression.

CONCLUSION

We highlight the therapeutic potential of SenA in cholestatic liver diseases by elucidating its role in epigenetic regulation.

HDAC3 as an Emerging Therapeutic Target for Alzheimer's Disease and other Neurological Disorders

Alzheimer's disease (AD) is the most common cause of dementia in the aged population. Histone acetylation is a major epigenetic mechanism linked to memory formation and cognitive function. Histone deacetylases (HDACs) are responsible for the deacetylation of lysine residues in histone proteins. Although pan-HDAC inhibitors are effective in ameliorating AD phenotypes in preclinical models, they are associated with potential unfavorable adverse effects and barely translated into clinical trials. Therefore, the development of novel HDAC inhibitors with a well isoform-selectivity has been desired in AD drug discovery. Among various HDAC isoforms, HDAC3 is highly expressed in neurons and exhibits detrimental effects on synaptic plasticity and cognitive function. Moreover, HDAC3 provokes neuroinflammation and neurotoxicity and contributes to AD pathogenesis. In this review, we highlight HDAC3 as an attractive therapeutic target for disease-modifying therapy in AD. In addition, we discuss the therapeutic potential of HDAC3 inhibitors in other neurological disorders.

A genetically encoded fluorescent biosensor for visualization of acetyl-CoA in live cells

Acetyl-coenzyme A is a central metabolite that participates in many cellular pathways. Evidence suggests that acetyl-CoA metabolism is highly compartmentalized in mammalian cells. Yet methods to measure acetyl-CoA in living cells are lacking. Herein, we engineered an acetyl-CoA biosensor from the bacterial protein PanZ and circularly permuted green fluorescent protein (cpGFP). The sensor, "PancACe," has a maximum change of ∼2-fold and a response range of ∼10 μM-2 mM acetyl-CoA. We demonstrated that the sensor has a greater than 7-fold selectivity over coenzyme A, butyryl-CoA, malonyl-CoA, and succinyl-CoA, and a 2.3-fold selectivity over propionyl-CoA. We expressed the sensor in E. coli and showed that it enables detection of rapid changes in acetyl-CoA levels. By localizing the sensor to either the cytoplasm, nucleus, or mitochondria in human cells, we showed that it enables subcellular detection of changes in acetyl-CoA levels, the magnitudes of which agreed with an orthogonal PicoProbe assay.

ACSS2 acts as a lactyl-CoA synthetase and couples KAT2A to function as a lactyltransferase for histone lactylation and tumor immune evasion

Lactyl-coenzyme A (CoA)-dependent histone lysine lactylation impacts gene expression and plays fundamental roles in biological processes. However, mammalian lactyl-CoA synthetases and their regulation of histone lactylation have not yet been identified. Here, we demonstrate that epidermal growth factor receptor (EGFR) activation induces extracellular signal-regulated kinase (ERK)-mediated S267 phosphorylation of acetyl-CoA synthetase 2 (ACSS2) and its subsequent nuclear translocation and complex formation with lysine acetyltransferase 2A (KAT2A). Importantly, ACSS2 functions as a bona fide lactyl-CoA synthetase and converts lactate to lactyl-CoA, which binds to KAT2A as demonstrated by a co-crystal structure analysis. Consequently, KAT2A acts as a lactyltransferase to lactylate histone H3, leading to the expression of Wnt/β-catenin, NF-κB, and PD-L1 and brain tumor growth and immune evasion. A combination treatment with an ACSS2-KAT2A interaction-blocking peptide and an anti-PD-1 antibody induces an additive tumor-inhibitory effect. These findings uncover ACSS2 and KAT2A as hitherto unidentified lactyl-CoA synthetase and lactyltransferase, respectively, and the significance of the ACSS2-KAT2A coupling in gene expression and tumor development.

Sex differences in cognition, anxiety-phenotype and therapeutic effect of metformin in the aged apoE-TR mice

BACKGROUND

Apolipoprotein E4 (ApoE4) is associated with an increased risk of Alzheimer's disease (AD), depression, and anxiety, which were reported to improve after the administration of metformin. However, sex influence on the effect of ApoE4 and metformin on cognition and mental health is poorly understood.

METHODS

ApoE3-TR and apoE4-TR mice of both sexes were randomly assigned to the normal saline and metformin groups from 13 months to 18 months of age. Behavior tests (MWM, EPM, OFT, TST, FST) were conducted to assess cognition, anxiety, and depression-like behaviors. The mice's blood glucose was also recorded.

RESULTS

Male aged apoE4-TR mice are more vulnerable to cognitive decline than females. Metformin improves the spatial memory of female, but not male apoE3-TR mice and female apoE4-TR mice while aggravating the cognitive impairment of male apoE4-TR mice. The anxiety-like phenotypes in male apoE4-TR mice are more severe than in male apoE3-TR mice, while metformin ameliorates the anxiety-like behaviors in the male apoE4-TR mice but not in male apoE3-TR mice. In addition, metformin alleviates depression-like behaviors in male and female apoE4-TR mice. The hypoglycemic effect of metformin is insignificant in both male and female apoE4-TR mice.

CONCLUSIONS

Male sex exacerbates APOE4-related cognitive impairment and anxiety in aged mice and is insensitive to the cognition improvement effect of metformin in the aged apoE3 mice. Male sex with APOE4 may experience more severe cognitive impairment after treatment with metformin while sensitive to the anti-anxiety effects of metformin. These findings identify sex-specific effects on ApoE4-based dementia, anxiety prevention, and therapy, emphasizing the importance of further sex dimension analyses in vivo and clinical studies.

Dysregulation of lipid metabolism in chronic kidney disease and the role of natural products

Dysregulation of lipid metabolism plays a key role in the onset and progression of CKD, and a thorough understanding of its regulatory mechanisms is essential for the development of effective treatments. In recent years, an increasing number of studies have focused on the pharmacological activities of natural products and their application in the treatment of chronic diseases. Natural products, including plant extracts and bioactive compounds, have been shown to exert anti-inflammatory, antioxidant, antifibrosis, and anti-apoptotic effects through various signaling pathways in the treatment of CKD. Many natural products have been shown to target dysregulated lipid metabolism through various signaling pathways. This review summarizes the key regulatory factors and signaling pathways involved in the dysregulation of lipid metabolism in chronic kidney disease (CKD), highlighting their importance as potential therapeutic targets. Recently published research on the potential therapeutic benefits of natural products for the treatment of CKD was described. These studies have revealed the multi-target role of natural products in the regulation of lipid metabolism. Natural products show great potential in targeting lipid metabolism-related pathways, offering a novel research direction for the treatment of CKD while providing a scientific basis and experimental support for the development of new treatment strategies.

Discovery and mechanism of a highly selective, antifungal acetyl CoA synthetase inhibitor

Acetyl CoA synthetases (ACS) have emerged as drug targets for the treatment of cancer, metabolic diseases as well as fungal and parasitic infections. Although a variety of small molecule ACS inhibitors have been discovered, the systematic optimization of these molecules has been slowed by a lack of structural information regarding their mechanism of inhibition. Through a chemical genetic-based, synthetic lethal screen of the human fungal pathogen Cryptococcus neoformans, we identified an isoxazole-based ACS inhibitor with antifungal activity and exquisite selectivity for the C. neoformans Acs1 relative to human ACSS2 as well as other fungal ACSs. Xray crystallographic characterization of the isoxazole-CnAcs1 complex revealed that the isoxazole functions as an acetyl CoA mimic and occupies both the acetyl- and CoA-binding sites of CnAcs1. Consistent with this novel mode of inhibition, the isoxazoles display uncompetitive inhibition kinetics that are similar to antimalarial ACS inhibitors also proposed to target the CoA binding site. Consequently, these data provide structural and mechanistic insights into the remarkable selectivity of Acetyl CoA pocket-targeting ACS inhibitors. In addition, these data provide strong proof-of-principle that targeting fungal and parasitic ACSs for the development of novel anti-infectives can be achieved with high selectivity and, thereby, low host toxicity.

Effects of the therapeutic correction of U1 snRNP complex on Alzheimer's disease

The U1 snRNP complex recognizes pre-mRNA splicing sites in the early stages of spliceosome assembly and suppresses premature cleavage and polyadenylation. Its dysfunction may precede Alzheimer's disease (AD) hallmarks. Here we evaluated the effects of a synthetic single-stranded cDNA (APT20TTMG) that interacts with U1 snRNP, in iPSC-derived neurons from a donor diagnosed with AD and in the SAMP8 mouse model. APT20TTMG effectively binds to U1 snRNP, specifically decreasing TAU in AD neurons, without changing mitochondrial activity or glutamate. Treatment enhanced neuronal electrical activity, promoted an enrichment of differentially expressed genes related to key processes affected by AD. In SAMP8 mice, APT20TTMG reduced insoluble pTAU in the hippocampus, amyloid-beta and GFAP in the cortex, and U1-70 K in both brain regions, without cognitive changes. This study highlights the correction of the U1 snRNP complex as a new target for AD.

The impact of sex on memory during aging and Alzheimer's disease progression: Epigenetic mechanisms

Alzheimer's disease (AD) is a leading cause of dementia, disability, and death in the elderly. While the etiology of AD is unknown, there are several established risk factors for the disease including, aging, female sex, and genetics. However, specific genetic mutations only account for a small percentage (1-5%) of AD cases and the much more common sporadic form of the disease has no causative genetic basis, although certain risk factor genes have been identified. While the genetic code remains static throughout the lifetime, the activation and expression levels of genes change dynamically over time via epigenetics. Recent evidence has emerged linking changes in epigenetics to the pathogenesis of AD, and epigenetic alterations also modulate cognitive changes during physiological aging. Aging is the greatest risk factor for the development of AD and two-thirds of all AD patients are women, who experience an increased rate of symptom progression compared to men of the same age. In humans and other mammalian species, males and females experience aging differently, raising the important question of whether sex differences in epigenetic regulation during aging could provide an explanation for sex differences in neurodegenerative diseases such as AD. This review explores distinct epigenetic changes that impact memory function during aging and AD, with a specific focus on sexually divergent epigenetic alterations (in particular, histone modifications) as a potential mechanistic explanation for sex differences in AD.

Progress in Lactate Metabolism and Its Regulation via Small Molecule Drugs

Lactate, once viewed as a byproduct of glycolysis and a metabolic "waste", is now recognized as an energy-providing substrate and a signaling molecule that modulates cellular functions under pathological conditions. The discovery of histone lactylation in 2019 marked a paradigm shift, with subsequent studies revealing that lactate can undergo lactylation with both histone and non-histone proteins, implicating it in the pathogenesis of various diseases, including cancer, liver fibrosis, sepsis, ischemic stroke, and acute kidney injury. Aberrant lactate metabolism is associated with disease onset, and its levels can predict disease outcomes. Targeting lactate production, transport, and lactylation may offer therapeutic potential for multiple diseases, yet a systematic summary of the small molecules modulating lactate and its metabolism in various diseases is lacking. This review outlines the sources and clearance of lactate, as well as its roles in cancer, liver fibrosis, sepsis, ischemic stroke, myocardial infarction, and acute kidney injury, and summarizes the effects of small molecules on lactate regulation. It aims to provide a reference and direction for future research.

Utilizing integrated bioinformatics and machine learning approaches to elucidate biomarkers linking sepsis to fatty acid metabolism-associated genes

Sepsis, characterized as a systemic inflammatory response triggered by the invasion of pathogens, represents a continuum that may escalate from mild systemic infection to severe sepsis, potentially resulting in septic shock and multiple organ dysfunction syndrome. Advancements in lipidomics and metabolomics have unveiled the complex role of fatty acid metabolism (FAM) in both healthy and pathological states. Leveraging bioinformatics, this investigation aimed to identify and substantiate potential FAM-related genes (FAMGs) implicated in sepsis. The approach encompassed a differential expression analysis across a pool of 36 candidate FAMGs. GSEA and GSVA were employed to assess the biological significance and pathways associated with these genes. Furthermore, Lasso regression and SVM-RFE methodologies were implemented to determine key hub genes and assess the diagnostic prowess of nine selected FAMGs in sepsis identification. The study also investigated the correlation between these hub FAMGs. Validation was conducted through expression-level analysis using the GSE13904 and GSE65682 datasets. The study identified 13 sepsis-associated FAMGs, including ABCD2, ACSL3, ACSM1, ACSS1, ACSS2, ACOX1, ALDH9A1, ACACA, ACACB, FASN, OLAH, PPT1, and ELOVL4. As demonstrated by functional enrichment analysis results, these genes played key roles in several critical biological pathways, such as the Peroxisome, PPAR signaling pathway, and Insulin signaling pathway, all of which are intricately linked to metabolic regulation and inflammatory responses. The diagnostic potential of these FAMGs was further highlighted. In short, the expression patterns of these FAMGs c effectively distinguished sepsis cases from non-septic controls, which suggested that they may be promising biomarkers for early sepsis detection. This discovery not only enhanced our understanding of the molecular mechanisms underpinning sepsis but also paved the way for developing novel diagnostic tools and therapeutic strategies targeting metabolic dysregulation in septic patients. This research sheds light on 13 FAMGs associated with sepsis, providing valuable insights into novel biomarkers for this condition and facilitating the monitoring of its progression. These findings underscore the significance of purine metabolism in sepsis pathogenesis and open avenues for further investigation into therapeutic targets.

SETD2 deficiency in peripheral sensory neurons induces allodynia by promoting NMDA receptor expression through NFAT5 in rodent models

Histone methylations play a crucial role in the development of neuropathic pain, and SET domain containing 2 (SETD2), a histone methyltransferase, serves as the sole tri-methylase known to catalyze H3K36me3 at the gene body. The N-methyl-d-aspartate receptor (NMDAR) is activated and mediates excitatory synaptic transmission in neuropathic pain. Nevertheless, the involvement of SETD2 in neuropathic pain and the specific regulatory mechanisms affecting NMDARs remain poorly understood. The expression levels of SETD2 were significantly decreased in the spinal cord and dorsal root ganglion (DRG) of rodents undergoing neuropathic pain induced by sciatic nerve chronic constrictive injury. Lentiviral shRNA-mediated SETD2 knockdown and conditional knockout in sensory neurons caused sustained NMDAR upregulation in DRG and spinal cord, which resulted in heightened neuronal excitability and increased pain hypersensitivity. SETD2 deficiency also led to reduced H3K36me3 deposition within the Grin1 (glutamate ionotropic receptor NMDA type subunit 1) gene body, thereby promoting aberrant transcription of the NMDARs subunit GluN1. The absence of SETD2 in the DRG potentiated neuronal excitability and increased presynaptic NMDAR activity in the spinal dorsal horn. Chromatin immunoprecipitation sequencing targeting H3K36me3 identified NFAT5 as a co-transcription factor in the transcriptional regulation of Grin1. These findings highlight SETD2 as a key regulator in pain signal transmission and offered new perspectives on the development of analgesics through the targeted modulation of epigenetic mechanisms.

Brain Short-Chain Fatty Acids Induce ACSS2 to Ameliorate Depressive-Like Behavior via PPARγ-TPH2 Axis

Short-chain fatty acids (SCFAs) have been increasingly evidenced to be important bioactive metabolites of the gut microbiota and transducers in controlling diverse psychiatric or neurological disorders via the microbiota-gut-brain axis. However, the precise mechanism by which brain SCFAs extert multiple beneficial effects is not completely understood. Our previous research has demonstrated that the acetyl-coenzyme A synthetase short-chain family member 2 (ACSS2) is a novel target of the rapid and long-lasting antidepressant responses. Here, we show that micromolar SCFAs significantly augment both total cellular and nuclear ACSS2 to trigger tryptophan hydroxylase 2 (TPH2) promoter histone acetylation and its transcription in SH-SY5Y cells. In chronic-restraint-stress-induced depression mice, neuronal ACSS2 knockdown by stereotaxic injection of adeno-associated virus in the hippocampus abolished SCFA-mediated improvements in depressive-like behaviors of mice, supporting that ACSS2 is required for SCFA-mediated antidepressant responses. Mechanistically, the peroxisome-proliferator-activated receptor gamma (PPARγ) is identified as a novel partner of ACSS2 to activate TPH2 transcription. Importantly, PPARγ is also responsible for SCFA-mediated antidepressant-like effects via ACSS2-TPH2 axis. To further support brain SCFAs as a therapeutic target for antidepressant effects, d-mannose, which is a naturally present hexose, can significantly reverse the dysbiosis of gut microbiota in the chronic-restraint-stress-exposure mice and augment brain SCFAs to protect against the depressive-like behaviors via ACSS2-PPARγ-TPH2 axis. In summary, brain SCFAs can activate ACSS2-PPARγ-TPH2 axis to play the antidepressive-like effects, and d-mannose is suggested to be an inducer of brain SCFAs in resisting depression.

Gut microbiota-host lipid crosstalk in Alzheimer's disease: implications for disease progression and therapeutics

Trillions of intestinal bacteria in the human body undergo dynamic transformations in response to physiological and pathological changes. Alterations in their composition and metabolites collectively contribute to the progression of Alzheimer's disease. The role of gut microbiota in Alzheimer's disease is diverse and complex, evidence suggests lipid metabolism may be one of the potential pathways. However, the mechanisms that gut microbiota mediate lipid metabolism in Alzheimer's disease pathology remain unclear, necessitating further investigation for clarification. This review highlights the current understanding of how gut microbiota disrupts lipid metabolism and discusses the implications of these discoveries in guiding strategies for the prevention or treatment of Alzheimer's disease based on existing data.

Novel histone post-translational modifications in Alzheimer's disease: current advances and implications

Alzheimer's disease (AD) has a complex pathogenesis, and multiple studies have indicated that histone post-translational modifications, especially acetylation, play a significant role in it. With the development of mass spectrometry and proteomics, an increasing number of novel HPTMs, including lactoylation, crotonylation, β-hydroxybutyrylation, 2-hydroxyisobutyrylation, succinylation, and malonylation, have been identified. These novel HPTMs closely link substance metabolism to gene regulation, and an increasing number of relevant studies on the relationship between novel HPTMs and AD have become available. This review summarizes the current advances and implications of novel HPTMs in AD, providing insight into the deeper pathogenesis of AD and the development of novel drugs.

A genetically-encoded fluorescent biosensor for visualization of acetyl-CoA in live cells

Acetyl-coenzyme A is a central metabolite that participates in many cellular pathways. Evidence suggests that acetyl-CoA production and consumption are highly compartmentalized in mammalian cells. Yet methods to measure acetyl-CoA in living cells are lacking. In this work, we engineer an acetyl-CoA biosensor from the bacterial protein PanZ and circularly permuted green fluorescent protein (cpGFP). We biochemically characterize the sensor and demonstrate its selectivity for acetyl-CoA over other CoA species. We then deploy the biosensor in E. coli and HeLa cells to demonstrate its utility in living cells. In E. coli, we show that the biosensor enables detection of rapid changes in acetyl-CoA levels. In human cells, we show that the biosensor enables subcellular detection and reveals the compartmentalization of acetyl-CoA metabolism.

Gut microbiota regulates hepatic ischemia-reperfusion injury-induced cognitive dysfunction via the HDAC2-ACSS2 axis in mice

AIMS

Hepatic ischemia-reperfusion injury (HIRI) resulting from hepatic inflow occlusion, which is a common procedure in liver surgery is inevitable. Previous research has confirmed that the cognitive dysfunction induced by HIRI is closely related to dysbiosis of the gut microbiota. This research aims to investigate the mechanisms underlying this complication.

METHODS

C57BL/6 mice underwent hepatic ischemia experimentally through the occlusion of the left hepatic artery and portal vein. To assess the HDAC2-ACSS2 axis, gut microbiota transplantation. Enzyme-linked immunosorbent assay and LC/MS short-chain fatty acid detection were utilized.

RESULTS

The findings indicated a notable decline in ACSS2 expression in the hippocampus of mice experiencing hepatic ischemia-reperfusion injury, emphasizing the compromised acetate metabolism in this particular area. Furthermore, the cognitive impairment phenotype and the dysregulation of the HDAC2-ACSS2 axis could also be transmitted to germ-free mice via fecal microbial transplantation. Enzyme-linked immunosorbent assay revealed reduced Acetyl-coenzyme A (acetyl-CoA) and Acetylated lysine levels in the hippocampus.

CONCLUSION

These findings suggest that acetate metabolism is impaired in the hippocampus of HIRI-induced cognitive impairment mice and related to dysbiosis, leading to compromised histone acetylation.

Sodium butyrate alleviates lead-induced neuroinflammation and improves cognitive and memory impairment through the ACSS2/H3K9ac/BDNF pathway

Lead is an environmentally widespread neurotoxic pollutant. Although the neurotoxicity of lead has been found to be closely associated with metabolic disorders, the effects of short-chain fatty acids on the neurotoxicity of lead and its mechanisms have not yet been explored. In this study, the results of open field tests and Morris water maze tests demonstrated that chronic lead exposure caused learning and memory deficits and anxiety-like symptoms in mice. The serum butyric acid content of lead-treated mice decreased in a dose-dependent manner, and oral administration of butyrate significantly improved cognitive memory impairment and anxiety symptoms in lead-exposed mice. Moreover, butyrate alleviated neuroinflammation caused by lead exposure by inhibiting the STAT3 signaling in microglia. Butyrate also promoted the expression of acetyl-CoA synthetase ACSS2 in hippocampal neurons, thereby increasing the content of acetyl-CoA and restoring the expression of both histone H3K9ac and the downstream BDNF. We also found that the median butyric acid concentration in high-lead exposure humans was remarkably lower than that in the low-lead exposure humans (45.16 μg/L vs. 60.92 μg/L, P < 0.01), and that butyric acid significantly mediated the relationship of lead exposure with the Montreal cognitive assessment scores, with a contribution rate of 27.57 %. In conclusion, our results suggest that butyrate supplementation is a possible therapeutic strategy for lead-induced neurotoxicity.

Histone acetylation in an Alzheimer's disease cell model promotes homeostatic amyloid-reducing pathways

Alzheimer's Disease (AD) is a disorder characterized by cognitive decline, neurodegeneration, and accumulation of amyloid plaques and tau neurofibrillary tangles in the brain. Dysregulation of epigenetic histone modifications may lead to expression of transcriptional programs that play a role either in protecting against disease genesis or in worsening of disease pathology. One such histone modification, acetylation of histone H3 lysine residue 27 (H3K27ac), is primarily localized to genomic enhancer regions and promotes active gene transcription. We previously discovered H3K27ac to be more abundant in AD patient brain tissue compared to the brains of age-matched non-demented controls. In this study, we use iPSC-neurons derived from familial AD patients with an amyloid precursor protein (APP) duplication (APPDup neurons) as a model to study the functional effect of lowering CBP/P300 enzymes that catalyze H3K27ac. We found that homeostatic amyloid-reducing genes were upregulated in the APPDup neurons compared to non-demented controls. We lowered CBP/P300 to reduce H3K27ac, which led to decreased expression of numerous of these homeostatic amyloid-reducing genes, along with increased extracellular secretion of a toxic amyloid-β species, Aβ(1-42). Our findings suggest that epigenomic histone acetylation, including H3K27ac, drives expression of compensatory genetic programs in response to AD-associated insults, specifically those resulting from APP duplication, and thus may play a role in mitigating AD pathology in neurons.