Gene-environment interactions in Alzheimer disease: the emerging role of epigenetics

Association of healthy lifestyle with excess risk of dementia in individuals with hypertension

BackgroundThe extent to which hypertension-related excess risk of dementia can be mitigated or eradicated through lifestyle factor modification remains unclear.ObjectiveTo explore the association between lifestyle behaviors and hypertension-related excess risk of dementia.MethodsIn this prospective cohort study using data from the UK Biobank, participants were enrolled from 2006 to 2010 and followed up until December 2022. A healthy lifestyle score was constructed by assigning one point for each of the seven selected healthy lifestyle factors. The association of dementia risk in individuals with hypertension according to the healthy lifestyle score was compared to individuals without hypertension.ResultsThis study included 337,378 individuals. During a median follow-up of 13.6 years, 5390 participants developed dementia. A higher healthy lifestyle score was associated with a gradual decrease in the excess risk of dementia for individuals with hypertension compared to individuals without hypertension. Excess dementia risk was not detected among individuals with hypertension who adopted at least six healthy lifestyle factors (hazard ratio (HR) = 1.05 (95% confidence interval (CI): 0.96-1.14)) for six scores; HR = 0.93 (95% CI: 0.82-1.06 for seven scores). The protective association between adhering to all seven healthy lifestyle factors and dementia was significantly stronger for individuals <60 years old than for individuals ≥60 years old.ConclusionsFor individuals with hypertension who adopted at least six healthy lifestyle factors had no hypertension-related excess risk of dementia.

Reversing Epigenetic Dysregulation in Neurodegenerative Diseases: Mechanistic and Therapeutic Considerations

Epigenetic dysregulation has emerged as an important player in the pathobiology of neurodegenerative diseases (NDDs), such as Alzheimer's, Parkinson's, and Huntington's diseases. Aberrant DNA methylation, histone modifications, and dysregulated non-coding RNAs have been shown to contribute to neuronal dysfunction and degeneration. These alterations are often exacerbated by environmental toxins, which induce oxidative stress, inflammation, and genomic instability. Reversing epigenetic aberrations may offer an avenue for restoring brain mechanisms and mitigating neurodegeneration. Herein, we revisit the evidence suggesting the ameliorative effects of epigenetic modulators in toxin-induced models of NDDs. The restoration of normal gene expressions, the improvement of neuronal function, and the reduction in pathological markers by histone deacetylase (HDAC) and DNA methyltransferase (DNMT) inhibitors have been demonstrated in preclinical models of NDDs. Encouragingly, in clinical trials of Alzheimer's disease (AD), HDAC inhibitors have caused improvements in cognition and memory. Combining these beneficial effects of epigenetic modulators with neuroprotective agents and the clearance of misfolded amyloid proteins may offer synergistic benefits. Reinforced by the emerging methods for more effective and brain-specific delivery, reversibility, and safety considerations, epigenetic modulators are anticipated to minimize systemic toxicity and yield more favorable outcomes in NDDs. In summary, although still in their infancy, epigenetic modulators offer an integrated strategy to address the multifactorial nature of NDDs, altering their therapeutic landscape.

The ISN Neuroscience School, Ondo 2024, Gene-environment interactions in neurological disorders: a contemporary update

Short summer courses focusing on the nervous system, commonly called Neuroscience Schools, are great venues for advancing training globally, particularly in low-middle income countries (LMICs). The ISN Neuroscience School attracted graduate students, postdoctoral fellows, early career researchers, and seasoned neuroscientists. The school was sponsored by the International Society for Neurochemistry (ISN) with additional support from the Company of Biologists. The school was held between 11th and 16th August, 2024, at the University of Medical Science, Ondo, Nigeria. Leading authorities in the field gave a series of talks during the event, summarizing the most recent findings on how environmental variables and genetic predispositions interact to affect the development and course of neurological illnesses. Through hands-on activities during practical sessions, participants gained a deeper knowledge of the approaches used to examine these interactions. Student pitches also promoted multidisciplinary cooperation and critical thinking by showcasing creative concepts and research ideas. The study of gene-environment interactions has several implications for the diagnosis, treatment, and prevention of neurological disorders. In this meeting report, we summarize and discuss the relevance of the school's activities while also highlighting prospects in this field in the African region.

Scorpion Venom Heat-Resistant Synthetic Peptide Alleviates Neuronal Necroptosis in Alzheimer's Disease Model by Regulating Lnc Gm6410 Under PM2.5 Exposure

Recent epidemiological studies have indicated that exposure to particulate matter with an aerodynamic diameter of 2.5 μm or less in the ambient air (PM2.5) is significantly associated with an elevated risk of developing Alzheimer's disease (AD) and its progression. Scorpion venom heat-resistant synthetic peptide (SVHRSP) exhibits anti-inflammatory and neuroprotective properties. However, the exact ways in which SVHRSP mitigates the progression of AD induced by PM2.5 are still unknown. Long non-coding RNA (lncRNA) plays a crucial role in various biological processes. Necroptosis, a form of programmed cell death, has garnered considerable attention in recent years. This study aims to investigate whether Lnc Gm16410 and neuronal necroptosis are involved in PM2.5-exacerbated AD progression and the mechanisms of SVHRSP in alleviating this process. Through the establishment of a PM2.5 exposure model in AD mice and an in vitro model, it was found that PM2.5 exposure could promote necroptosis and the down-regulation of Lnc Gm16410, thereby promoting the progression of AD. Behavioral tests showed that SVHRSP alleviated cognitive impairment in PM2.5-induced AD mice. WB, qRT-PCR, and other molecular biological assays indicate that Lnc Gm16410 regulates neuronal necroptosis under PM2.5 exposure via the p38 MAPK pathway. SVHRSP is a potential regulator of AD progression by regulating Lnc Gm16410 to alleviate PM2.5 exposure-induced necroptosis. These findings offer new insights into the mechanism through which PM2.5 exposure accelerates the progression of AD, examined from the perspective of LncRNA. Furthermore, we offer new targets for the treatment and prevention of AD following PM2.5 exposure by investigating the mechanism of action of SVHRSP in alleviating AD.

Microbial infection instigates tau-related pathology in Alzheimer's disease via activating neuroimmune cGAS-STING pathway

Microbial infection, the strong trigger to directly induce inflammation in brain, is long considered a risk factor of Alzheimer's disease (AD), but how these infections contribute to neurodegeneration remains underexplored. To examine the effect of herpes simplex virus type 1 (HSV-1) infection on tauopathy in local hippocampus of P301S mice, we utilized a modified HSV-1 strain (mHSV-1) potentially relevant to AD, we found that its infection promotes tau-related pathology in part via activating neuroimmune cGAS-STING pathway in the tau mouse model. Specifically, Sting ablation causes the detectable improvement of neuronal dysfunction and loss in P301S mice, which is causally linked to lowered proinflammatory status in the brain. Administration of STING inhibitor H-151 alleviates neuroinflammation and tau-related pathology in P301S mice. These results jointly suggest that herpesviral infection, as the vital environmental risk factor, could induce tau-related pathology in AD pathogenesis partially via neuroinflammatory cGAS-STING pathway.

Platelets mirror changes in the frontal lobe antioxidant system in Alzheimer's disease

INTRODUCTION

Blood biomarkers reflecting Alzheimer's disease (AD) pathophysiology can improve diagnosis and treatment.

METHODS

We applied top-down proteomics to compare frontal lobe from 17 AD cases and 11 controls to blood platelets from a second independent study group of 124 AD patients, 61 with mild cognitive impairment (MCI), and 168 controls. Findings were immunologically validated.

RESULTS

Sixty AD-associated proteoforms were identified in frontal lobe, with 26 identically represented in platelets. Validation in platelet samples confirmed elevated glutathione S-transferase omega 1 (GSTO1) levels linked to single nucleotide polymorphism (SNP) rs4925 and increased superoxide dismutase 1 (SOD1) levels in AD. Bioinformatics revealed copper chaperone for superoxide dismutase (CCS) and glutathione peroxidase 1 (GPX1) as integral partners of these antioxidant enzymes. Both were detected to be reduced in frontal lobes and platelets in AD. SOD1 and CCS are already changed in MCI.

DISCUSSION

These four novel blood biomarkers, integrated with traditional AD biomarkers, may facilitate patient risk assessment and treatment, with SOD1 and CCS alterations in MCI offering early diagnostic potential.

HIGHLIGHTS

Platelets mirror several Alzheimer's disease (AD)-dependent neuronal changes, valuable for blood tests. As a start, 60 AD-associated frontal lobe proteins were identified by top-down proteomics. Fifty percent of these 60 AD-affected brain proteins are represented identically in platelets. Among these, glutathione S-transferase omega 1 (GSTO1), superoxide dismutase 1 (SOD1), copper chaperone for superoxide dismutase (CCS), and glutathione peroxidase 1 (GPX1) are identically AD related in brain and platelets. SOD1 and its crucial activating partner CCS are altered in the platelets of patients with mild cognitive impairment.

Risk of Alzheimer's disease in Down syndrome: Insights gained by multi-omics

Individuals with Down syndrome (DS) are highly susceptible to Alzheimer's disease (AD). The integration of genomics, transcriptomics, epigenomics, proteomics, and metabolomics enables unprecedented understanding of DS-AD, offering a detailed picture of this complex issue. The vast -omics data also present challenges that reflect the complexity of genetic information flow. These studies nonetheless reveal critical mechanisms behind AD risk, including unique observations in DS that differ from those seen in the general population and familial dominant AD. In addition, the correlations between the AD polygenic risk score and proteins related to female infertility and autoimmune thyroiditis corroborate clinical observations. Metabolomic data reveal disrupted metabolic networks, offering prospects for a dynamic score to create specialized nutritional interventions. By adopting a multidimensional perspective with integrated reductionism, the evolving landscape presents an opportunity to identify promising directions for developing precision strategies to mitigate the impact of AD in the DS population. HIGHLIGHTS: Individuals with Down syndrome (DS) are highly susceptible to Alzheimer's disease (AD). DS-AD is characterized by its polygenic nature, extending beyond chromosome 21 with significant contributions from various chromosomes. DS-AD also presents unique features that differ from those observed in the general population and familial dominant AD. Our review consolidates key findings from genomics, transcriptomics, epigenomics, proteomics, and metabolomics, providing a comprehensive view of the molecular mechanisms underlying DS-AD. We highlight promising research directions to further elucidate the pathogenesis of DS-AD.

Unequal burdens: How structural socioeconomic inequality shapes brain health in aging and dementia

Structural socioeconomic inequality -the aggregate level unequal distribution of resources and opportunities within a region- significantly impacts brain health. Unlike traditional neuroscience approaches that focus on individual factors, recent studies highlight the biological embedding of macrosocial inequalities. We discuss studies on structural inequality that use EEG and f/MRI across diverse populations. Greater structural inequality is associated with adverse brain outcomes, such as reduced complexity, volume, and connectivity, particularly in temporo-posterior regions. Structural inequality significantly contributes to brain burden, even after accounting for individual demographics, and its effects are more pronounced in aging and dementia. This evidence opens a new framework for studying various physical (e.g., air pollution) and social (e.g., gender inequality, sociopolitical determinants) exposomes at the aggregate level in relation to brain health. Neuroscience can inform policymakers to address the positive brain health impacts of mitigating structural determinants of health through policies that enhance social safety and healthcare access.

A review of AI-based radiogenomics in neurodegenerative disease

Neurodegenerative diseases are chronic, progressive conditions that cause irreversible damage to the nervous system, particularly in aging populations. Early diagnosis is a critical challenge, as these diseases often develop slowly and without clear symptoms until significant damage has occurred. Recent advances in radiomics and genomics have provided valuable insights into the mechanisms of these diseases by identifying specific imaging features and genomic patterns. Radiogenomics enhances diagnostic capabilities by linking genomics with imaging phenotypes, offering a more comprehensive understanding of disease progression. The growing field of artificial intelligence (AI), including machine learning and deep learning, opens new opportunities for improving the accuracy and timeliness of these diagnoses. This review examines the application of AI-based radiogenomics in neurodegenerative diseases, summarizing key model designs, performance metrics, publicly available data resources, significant findings, and future research directions. It provides a starting point and guidance for those seeking to explore this emerging area of study.

BHCox: Bayesian heredity-constrained Cox proportional hazards models for detecting gene-environment interactions

BACKGROUND

Gene-environment (G × E) interactions play a critical role in understanding the etiology of diseases and exploring the factors that affect disease prognosis. There are several challenges in detecting G × E interactions for censored survival outcomes, such as the high dimensionality, complexity of environmental effects, and specificity of survival analysis. The effect heredity, which incorporates the dependence of the main effects and interactions in the analysis, has been widely applied in the study of interaction detection. However, it has not yet been applied to Bayesian Cox proportional hazards models for detecting interactions for censored survival outcomes.

RESULTS

In this study, we propose Bayesian heredity-constrained Cox proportional hazards (BHCox) models with novel spike-and-slab and regularized horseshoe priors that incorporate effect heredity to identify and estimate the main and interaction effects. The no-U-turn sampler (NUTS) algorithm, which has been implemented in the R package brms, was used to fit the proposed model. Extensive simulations were performed to evaluate and compare our proposed approaches with other alternative models. The simulation studies illustrated that BHCox models outperform other alternative models. We applied the proposed method to real data of non-small-cell lung cancer (NSCLC) and identified biologically plausible G × smoking interactions associated with the prognosis of patients with NSCLC.

CONCLUSIONS

In summary, BHCox can be used to detect the main effects and interactions and thus have significant implications for the discovery of high-dimensional interactions in censored survival outcome data.

Identification of Lipophagy-Related Gene Signature for Diagnosis and Risk Prediction of Alzheimer's Disease

Background: Recent research indicates that lipid metabolism and autophagy play crucial roles in the development of Alzheimer's disease (AD). Investigating the relationship between AD diagnosis and gene expression related to lipid metabolism, autophagy, and lipophagy may improve early diagnosis and the identification of therapeutic targets. Methods: Transcription datasets from AD patients were obtained from the Gene Expression Omnibus (GEO). Genes associated with lipid metabolism, autophagy, and lipophagy were sourced from the Gene Set Enrichment Analysis (GSEA) database and the Human Autophagy Database (HADb). Lipophagy-related hub genes were identified using a combination of Limma analysis, weighted gene co-expression network analysis (WGCNA), and machine learning techniques. Based on these hub genes, we developed an AD risk prediction nomogram and validated its diagnostic accuracy using three external validation datasets. Additionally, the expression levels of the hub genes were assessed through quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results: Our analysis identified three hub genes-ACBD5, GABARAPL1, and HSPA8-as being associated with AD progression. The nomogram constructed from these hub genes achieved an area under the curve (AUC) value of 0.894 for AD risk prediction, with all validation sets yielding AUC values greater than 0.8, indicating excellent diagnostic efficacy. qRT-PCR results further corroborated the associations between these hub genes and AD development. Conclusions: This study identified and validated three lipophagy-related hub genes and developed a reliable diagnostic model, offering insights into the pathology of AD and facilitating the diagnosis of AD patients.

Beliefs About the Causes of Alzheimer's Disease Among Latinos in New York City

Latinos face health disparities in Alzheimer's disease (AD), with high disease prevalence relative to non-Latino whites and barriers to healthcare access. Several studies have found misconceptions about AD among Latinos that were linked to reduced preventative or help-seeking behavior. To improve understanding of illness perceptions among Latinos, we examined beliefs about the causes of AD, one of the five dimensions of illness representations from Leventhal's Self-Regulation Theory, among a sample of N = 216 Latinos. We conducted in-depth, semi-structured interviews with participants aged 40 to 64 (average age 53 years) living in northern Manhattan. Seven distinct causes of AD were identified, though participants demonstrated a general understanding of AD as a multifactorial disease. Genetics was found to be the most endorsed cause of AD, followed by unhealthy lifestyle factors. Most Latinos who believed psychosocial factors played a critical role in AD development were first-generation immigrants. No participants attributed AD to a normal process of aging, and few ascribed the disease to brain damage from stroke or head injuries. Several participants expressed the belief that environmental contaminants can cause AD, which has received little mention in prior studies. Though only a small number thought AD could occur by chance, most participants remained uncertain about the exact causes of the disease and used lay knowledge to explain their beliefs. Our findings help identify areas where educational interventions would be beneficial in improving community knowledge and offer perspectives that can foster cultural competency in healthcare.

Alzheimer's disease and infectious agents: a comprehensive review of pathogenic mechanisms and microRNA roles

Alzheimer's Disease (AD) is the most prevalent type of dementia and is characterized by the presence of senile plaques and neurofibrillary tangles. There are various theories concerning the causes of AD, but the connection between viral and bacterial infections and their potential role in the pathogenesis of AD has become a fascinating area of research for the field. Various viruses such as Herpes simplex virus 1 (HSV-1), Epstein-Barr virus (EBV), Cytomegalovirus (CMV), influenza viruses, and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), as well as bacteria such as Chlamydia pneumoniae (CP), Helicobacter pylori (HP), Porphyromonas gingivalis (P. gingivalis), Spirochetes and eukaryotic unicellular parasites (e.g., Toxoplasma gondii), have been linked to AD due to their ability to activate the immune system, induce inflammation and increase oxidative stress, thereby leading to cognitive decline and AD. In addition, microRNAs (miRNAs) might play a crucial role in the pathogenesis mechanisms of these pathogens since they are utilized to target various protein-coding genes, allowing for immune evasion, maintaining latency, and suppressing cellular signaling molecules. Also, they can regulate gene expression in human cells. This article provides an overview of the association between AD and various infectious agents, with a focus on the mechanisms by which these pathogens may be related to the pathogenesis of AD. These findings suggest important areas for further research to be explored in future studies.

The Beneficial Effects of Lactobacillus Strains on Gut Microbiome in Alzheimer's Disease: A Systematic Review

BACKGROUND/OBJECTIVES

Growing evidence suggests that the gut-brain axis influences brain function, particularly the role of intestinal microbiota in modulating cognitive processes. Probiotics may alter brain function and behavior by modulating gut microbiota, with implications for neurodegenerative diseases like Alzheimer's disease (AD). The purpose of this review is to systematically review the current literature exploring the effects of probiotic supplementation on gut microbiota and cognitive function in AD and mild cognitive impairment (MCI).

METHODS

A comprehensive literature search was conducted across PubMed/Medline, Embase, and Scopus to identify relevant randomized controlled trials (RCTs) from inception to 20 August 2024. The search focused on comparing outcomes between intervention and control/placebo groups. Data searches, article selection, data extraction, and risk of bias assessment were performed in accordance with Cochrane guidelines.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no: CRD42023446796.

RESULTS

Data from four RCTs involving 293 Individuals (AD and MCI patients) receiving mainly Lactobacillus and Bifidobacterium strains showed some beneficial effects on cognitive function, altered gut microbiota composition, and positively affected metabolic biomarkers. However, variability in microbiota assessment across studies limits the interpretation of results. The limited number and quality of the existing studies make it difficult to draw definitive conclusions from the data. Additional high-quality research is clearly needed.

CONCLUSIONS

Probiotics show promise as an adjunctive intervention for cognitive decline, but larger, long-term trials are needed to confirm their efficacy and clinical applicability in neurodegenerative diseases like AD.

The Promise of Epigenetic Editing for Treating Brain Disorders

Brain disorders, especially neurodegenerative diseases, affect millions of people worldwide. There is no causal treatment available; therefore, there is an unmet clinical need for finding therapeutic options for these diseases. Epigenetic research has resulted in identification of various genomic loci with differential disease-specific epigenetic modifications, mainly DNA methylation. These biomarkers, although not yet translated into clinically approved options, offer therapeutic targets as epigenetic modifications are reversible. Indeed, clinical trials are designed to inhibit epigenetic writers, erasers, or readers using epigenetic drugs to interfere with epigenetic dysregulation in brain disorders. However, since such drugs elicit genome-wide effects and potentially cause toxicity, the recent developments in the field of epigenetic editing are gaining widespread attention. In this review, we provide examples of epigenetic biomarkers and epi-drugs, while describing efforts in the field of epigenetic editing, to eventually make a difference for the currently incurable brain disorders.

DNA Methylation in Alzheimer's Disease

To date, DNA methylation is the best characterized epigenetic modification in Alzheimer's disease. Involving the addition of a methyl group to the fifth carbon of the cytosine pyrimidine base, DNA methylation is generally thought to be associated with the silencing of gene expression. It has been hypothesized that epigenetics may mediate the interaction between genes and the environment in the manifestation of Alzheimer's disease, and therefore studies investigating DNA methylation could elucidate novel disease mechanisms. This chapter comprehensively reviews epigenomic studies, undertaken in human brain tissue and purified brain cell types, focusing on global methylation levels, candidate genes, epigenome wide approaches, and recent meta-analyses. We discuss key differentially methylated genes and pathways that have been highlighted to date, with a discussion on how new technologies and the integration of multiomic data may further advance the field.

Loss of the mitochondrial protein mitoNEET in mice is associated with cognitive impairments and increased neuroinflammation

BACKGROUND

Mitochondrial dysfunction is implicated in several neurodegenerative diseases associated with memory and cognitive deficits, including Alzheimer's disease. Changes in bioenergetic function results in reactive oxygen species, oxidative damage and consequently neuroinflammation, which contributes to neuronal cell loss.

OBJECTIVE

In this study, we evaluated the impact of the loss of the redox active [2Fe-2S] mitochondrial-associated protein mitoNEET (CISD1) on neuroinflammation and cognition using an age-appropriate preclinical model. While associations between neuroinflammation and poor cognitive impacts have been shown in recent work, little has been done to assess whether loss of mitoNEET is associated with changes in neuroinflammatory markers or negative cognitive-behavioral outcomes.

METHODS

Using 9-11-month-old mitoNEET knockout (CISD1-/-) and wild-type mice, we conducted a battery of cognitive tests to assess the impact of mitoNEET loss on performance. We then histologically evaluated the effect of absence of mitoNEET on markers of neuroinflammation in the aged brain.

RESULTS

We found loss of mitoNEET in mice was associated with a significant reduction in willingness to explore within an open field and impaired short-term spatial working memory in the Y-maze. We also found a significant reduction in novel object recognition memory that was gene-dependent and accompanied by reduced c-fos expression in hippocampus and cortical regions.

CONCLUSIONS

Our findings indicate that mitoNEET loss is significantly associated with impairments in cognitive-behavioral and neuroinflammatory outcomes; specifically, learning and memory, anxiety-like behaviors, neuroinflammation, and neural activation. This is the first study to demonstrate cognitive-associated behavioral deficits with neuroinflammation in the mitoNEET knockout mouse model.

Epigenetics in Neurodegenerative Diseases

Healthy brain functioning requires a continuous fine-tuning of gene expression, involving changes in the epigenetic landscape and 3D chromatin organization. Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD) are three multifactorial neurodegenerative diseases (NDDs) that are partially explained by genetics (gene mutations and genetic risk factors) and influenced by non-genetic factors (i.e., aging, lifestyle, and environmental conditions). Examining comprehensive studies of global and locus-specific (epi)genomic and transcriptomic alterations in human and mouse brain samples at the cell-type resolution has uncovered important phenomena associated with AD. First, DNA methylation and histone marks at promoters contribute to transcriptional dysregulation of genes that are directly implicated in AD pathogenesis (i.e., APP), neuroplasticity and cognition (i.e., PSD95), and microglial activation (i.e., TREM2). Second, the presence of AD genetic risk variants in cell-type-specific distal enhancers (i.e., BIN1 in microglia) alters transcription, presumably by disrupting associated enhancer-promoter interactions and chromatin looping. Third, epigenomic erosion is associated with widespread transcriptional disruption and cell identity loss. And fourth, aging, high cholesterol, air pollution, and pesticides have emerged as potential drivers of AD by inducing locus-specific and global epigenetic modifications that impact key AD-related pathways. Epigenetic studies in ALS/FTD also provide evidence that genetic and non-genetic factors alter gene expression profiles in neurons and astrocytes through aberrant epigenetic mechanisms. We additionally overview the recent development of potential new therapeutic strategies involving (epi)genetic editing and the use of small chromatin-modifying molecules (epidrugs).

Exposure to PFOA, PFOS, and PFHxS induces Alzheimer's disease-like neuropathology in cerebral organoids

Per- and polyfluoroalkyl substances (PFASs), a class of ubiquitous synthetic organic chemicals, are widely utilized across various industrial applications. However, the long-term neurological health effects of PFAS mixture exposure in humans remain poorly understood. To address this gap, we have designed a comprehensive study to predict and validate cell-type-specific neurotoxicity of PFASs using single-cell RNA sequencing (scRNA-seq) and cerebral organoids. Cerebral organoids were exposed to a PFAS mixture at concentrations of 1 × (10 ng/ml PFOS and PFOA, and 1 ng/ml PFHxS), 30 × , and 900 × over 35 days, with a follow-up analysis at day 70. Pathological alterations and lipidomic profiles were analyzed to identify disrupted molecular pathways and mechanisms. The scRNA-seq data revealed a significant impact of PFASs on neurons, suggesting a potential role in Alzheimer's Disease (AD) pathology, as well as intellectual and cognitive impairments. PFAS-treated cerebral organoids exhibited Aβ accumulation and tau phosphorylation. Lipidomic analyses further revealed lipid disturbances in response to PFAS mixture exposure, linking PFAS-induced AD-like neuropathology to sphingolipid metabolism disruption. Collectively, our findings provide novel insights into the PFAS-induced neurotoxicity, highlighting the significance of sphingolipid metabolism in the development of AD-like neuropathology. The use of cerebral organoids and scRNA-seq offers a powerful methodology for evaluating the health risks associated with environmental contaminants, particularly those with neurotoxic potential.

Extracellular vesicles: biological mechanisms and emerging therapeutic opportunities in neurodegenerative diseases

Extracellular vesicles (EVs) are membrane vesicles originating from different cells within the brain. The pathophysiological role of EVs in neurodegenerative diseases is progressively acknowledged. This field has advanced from basic biological research to essential clinical significance. The capacity to selectively enrich specific subsets of EVs from biofluids via distinctive surface markers has opened new avenues for molecular understandings across various tissues and organs, notably in the brain. In recent years, brain-derived EVs have been extensively investigated as biomarkers, therapeutic targets, and drug-delivery vehicles for neurodegenerative diseases. This review provides a brief overview of the characteristics and physiological functions of the various classes of EVs, focusing on the biological mechanisms by which various types of brain-derived EVs mediate the occurrence and development of neurodegenerative diseases. Concurrently, novel therapeutic approaches and challenges for the use of EVs as delivery vehicles are delineated.

Sex and tissue-specificity of piRNA regulation in adult mice following perinatal lead (Pb) exposure

Lead (Pb) is a neurotoxicant with early life exposure linked to long-term health effects. Piwi-interacting RNAs (piRNAs) are small non-coding RNAs that associate with PIWIL proteins to induce DNA methylation. It remains unknown whether Pb exposure influences piRNA expression. This study evaluated how perinatal Pb exposure (32 ppm in drinking water) impacts piRNA expression in adult mice and assessed piRNA dysregulation as a potential mechanism for Pb-induced toxicity. Pb exposure effects on piRNA expression and associated gene repression in the germline (testis/ovary) and soma (liver and brain) were evaluated. Small RNA sequencing was used to determine differentially expressed piRNAs, RT-qPCR to examine piRNA target expression, and whole genome bisulfite sequencing to evaluate target DNA methylation status. Three piRNAs (mmpiR-1500602, mmpiR-0201406, and mmpiR-0200026) were significant after multiple testing correction (all downregulated in the male Pb-exposed brain in comparison to control; FDR < 0.05). Within piOxiDB, TAO Kinase 3 was identified as a downstream mRNA target for one of the three Pb-sensitive piRNA. The Pb-exposed male brain exhibited increased Taok3 expression (p < 0.05) and decreased DNA methylation (FDR < 0.01). The results demonstrate that perinatal Pb exposure stably influences longitudinal piRNA expression in a tissue- and sex-specific manner, potentially via DNA methylation-directed mechanisms.

ANGPTL4-mediated microglial lipid droplet accumulation: Bridging Alzheimer's disease and obesity

Increasing evidence suggests that metabolic disorders such as obesity are implicated in the development of Alzheimer's disease (AD). The pathological buildup of lipids in microglia is regarded as a key indicator in brain aging and the progression of AD, yet the mechanisms behind this process remain uncertain. The adipokine ANGPTL4 is strongly associated with obesity and is thought to play a role in the advancement of neurodegenerative diseases. This study utilized RNA sequencing to identify differential expression in lipid-accumulating BV2 microglia and investigated the potential mechanism through ANGPTL4 overexpression in BV2. Subsequently, animal models and clinical data were employed to further explore alterations in circulating ANGPTL4 levels in AD. RNA sequencing results indicated a correlation between ANGPTL4 and microglial lipid accumulation. The overexpression of ANGPTL4 in microglia resulted in increased secretion of inflammatory factors, elevated oxidative stress levels, and diminished antiviral capacity. Furthermore, when simulating the coexistence of AD and obesity through combined treatment with Amyloid-Beta 1-42 peptide (Aβ) and Free Fatty Acids (FFA) in vitro, we observed a notable upregulation of ANGPTL4 expression, highlighting its potential role in the interplay between AD and obesity. In vivo experiments, we also observed a significant increase in ANGPTL4 expression in the hippocampus and plasma of APP/PS1 mice compared to wild-type controls. This was accompanied by heightened microglial activation and reduced expression of longevity-related genes in the hippocampus. Clinical data from the UK Biobank indicated that plasma ANGPTL4 levels are elevated in patients with AD when compared to healthy controls. Moreover, significantly higher ANGPTL4 levels were observed in obese AD patients relative to their non-obese counterparts. Our findings suggest that ANGPTL4-mediated microglial aging may serve as a crucial link between AD and obesity, proposing ANGPTL4 as a potential biomarker for AD.

Interactions between polycyclic aromatic hydrocarbons and genetic variants in the cGAS-STING pathway affect the risk of colorectal cancer

The cGAS-STING pathway plays an essential role in the activation of tumor immune cells. Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants with potential carcinogenicity, and their exposure is associated with the development of colorectal cancer. However, the impacts of genetic factors in the cGAS‒STING pathway and gene‒environment interactions on colorectal cancer remain understudied. We used logistic regression models and interaction analysis to evaluate the impact of genetic variants on colorectal cancer risk and gene‒environment interactions. We analysed the expression patterns of candidate genes based on the RNA-seq data. Molecular biology experiments were performed to investigate the impact of PAHs exposure on candidate gene expression and the progression of colorectal cancer. We identified the susceptibility locus rs3750511 in the cGAS‒STING pathway, which is associated with colorectal cancer risk. A negative interaction between TRAF2 rs3750511 and PAHs exposure was also identified. Single-cell RNA-seq analysis revealed significantly elevated expression of TRAF2 in colorectal cancer tissues compared with normal tissues, especially in T cells. BPDE exposure increased TRAF2 expression and the malignant phenotype of colorectal cancer cells. The treatment also further increased the expression of the TRAF2 downstream gene NF-κB and decreased the expression of Caspase8. Our results suggest that the genetic variant of rs3750511 affects the expression of TRAF2, thereby increasing the risk of colorectal cancer through interaction with PAHs. Our study provides new insights into the influence of gene‒environment interactions on the risk of developing colorectal cancer.

Gut microbiota dysbiosis in patients with Alzheimer's disease and correlation with multiple cognitive domains

Background

Accumulating evidence suggested that Alzheimer's disease (AD) was associated with altered gut microbiota. However, the relationships between gut microbiota and specific cognitive domains of AD patients have yet been fully elucidated. The aim of this study was to explore microbial signatures associated with global cognition and specific cognitive domains in AD patients and to determine their predictive value as biomarkers.

Methods

A total of 64 subjects (18 mild AD, 23 severe AD and 23 healthy control) were recruited in the study. 16 s rDNA sequencing was performed for the gut bacteria composition, followed by liquid chromatography electrospray ionization tandem mass spectrometry (LC/MS/MS) analysis of short-chain fatty acids (SCFAs). The global cognition, specific cognitive domains (abstraction, orientation, attention, language, etc.) and severity of cognitive impairment, were evaluated by Montreal Cognitive Assessment (MoCA) scores. We further identified characteristic bacteria and SCFAs, and receiver operating characteristic (ROC) curve was used to determine the predictive value.

Results

Our results showed that the microbiota dysbiosis index was significantly higher in the severe and mild AD patients compared to the healthy control (HC). Linear discriminant analysis (LDA) showed that 12 families and 17 genera were identified as key microbiota among three groups. The abundance of Butyricicoccus was positively associated with abstraction, and the abundance of Lachnospiraceae_UCG-004 was positively associated with attention, language, orientation in AD patients. Moreover, the levels of isobutyric acid and isovaleric acid were both significantly negatively correlated with abstraction, and level of propanoic acid was significantly positively associated with the attention. In addition, ROC models based on the characteristic bacteria Lactobacillus, Butyricicoccus and Lachnospiraceae_UCG-004 could effectively distinguished between low and high orientation in AD patients (area under curve is 0.891), and Butyricicoccus and Agathobacter or the combination of SCFAs could distinguish abstraction in AD patients (area under curve is 0.797 and 0.839 respectively).

Conclusion

These findings revealed the signatures gut bacteria and metabolite SCFAs of AD patients and demonstrated the correlations between theses characteristic bacteria and SCFAs and specific cognitive domains, highlighting their potential value in early detection, monitoring, and intervention strategies for AD patients.

Therapeutic Options in Alzheimer's Disease: From Classic Acetylcholinesterase Inhibitors to Multi-Target Drugs with Pleiotropic Activity

Alzheimer's disease (AD) is a complex/multifactorial brain disorder involving hundreds of defective genes, epigenetic aberrations, cerebrovascular alterations, and environmental risk factors. The onset of the neurodegenerative process is triggered decades before the first symptoms appear, probably due to a combination of genomic and epigenetic phenomena. Therefore, the primary objective of any effective treatment is to intercept the disease process in its presymptomatic phases. Since the approval of acetylcholinesterase inhibitors (Tacrine, Donepezil, Rivastigmine, Galantamine) and Memantine, between 1993 and 2003, no new drug was approved by the FDA until the advent of immunotherapy with Aducanumab in 2021 and Lecanemab in 2023. Over the past decade, more than 10,000 new compounds with potential action on some pathogenic components of AD have been tested. The limitations of these anti-AD treatments have stimulated the search for multi-target (MT) drugs. In recent years, more than 1000 drugs with potential MT function have been studied in AD models. MT drugs aim to address the complex and multifactorial nature of the disease. This approach has the potential to offer more comprehensive benefits than single-target therapies, which may be limited in their effectiveness due to the intricate pathology of AD. A strategy still unexplored is the combination of epigenetic drugs with MT agents. Another option could be biotechnological products with pleiotropic action, among which nosustrophine-like compounds could represent an attractive, although not definitive, example.

cis- and trans-regulatory contributions to a hierarchy of factors influencing gene expression variation

Gene expression variation results from numerous sources including genetic, environmental, life stage, and even the environment experienced by previous generations. While the importance of each has been demonstrated in diverse organisms, their relative contributions remain understudied because few investigations have simultaneously determined each within a single experiment. Here we quantified genome-wide gene expression traits in Drosophila, quantified the contribution of multiple different sources of trait variation and determined the molecular mechanisms underlying observed variation. Our results show that there is a clear hierarchy in our data with genome and developmental stage contributing on average considerably more than current and finally previous generation environmental effects. We also determined the role of cis and trans-regulatory changes across different sources of trait variation, highlighting their importance in adaptation and environmental responses and showing unexpectedly that transgenerational effects herein were predominantly associated with changes in trans-regulation.

Assessing the Impact and Cost-Effectiveness of Exposome Interventions on Alzheimer's Disease: A Review of Agent-Based Modeling and Other Data Science Methods for Causal Inference

Background: The exposome (e.g., totality of environmental exposures) and its role in Alzheimer's Disease and Alzheimer's Disease and Related Dementias (AD/ADRD) are increasingly critical areas of study. However, little is known about how interventions on the exposome, including personal behavioral modification or policy-level interventions, may impact AD/ADRD disease burden at the population level in real-world settings and the cost-effectiveness of interventions. Methods: We performed a critical review to discuss the challenges in modeling exposome interventions on population-level AD/ADRD burden and the potential of using agent-based modeling (ABM) and other advanced data science methods for causal inference to achieve this. Results: We describe how ABM can be used for empirical causal inference modeling and provide a virtual laboratory for simulating the impacts of personal and policy-level interventions. These hypothetical experiments can provide insight into the optimal timing, targeting, and duration of interventions, identifying optimal combinations of interventions, and can be augmented with economic analyses to evaluate the cost-effectiveness of interventions. We also discuss other data science methods, including structural equation modeling and Mendelian randomization. Lastly, we discuss challenges in modeling the complex exposome, including high dimensional and sparse data, the need to account for dynamic changes over time and over the life course, and the role of exposome burden scores developed using item response theory models and artificial intelligence to address these challenges. Conclusions: This critical review highlights opportunities and challenges in modeling exposome interventions on population-level AD/ADRD disease burden while considering the cost-effectiveness of different interventions, which can be used to aid data-driven policy decisions.

Gut-Brain Nexus: Mapping Multi-Modal Links to Neurodegeneration at Biobank Scale

Alzheimer's disease (AD) and Parkinson's disease (PD) are influenced by genetic and environmental factors. Using data from UK Biobank, SAIL Biobank, and FinnGen, we conducted an unbiased, population-scale study to: 1) Investigate how 155 endocrine, nutritional, metabolic, and digestive system disorders are associated with AD and PD risk prior to their diagnosis, considering known genetic influences; 2) Assess plasma biomarkers' specificity for AD or PD in individuals with these conditions; 3) Develop a multi-modal classification model integrating genetics, proteomics, and clinical data relevant to conditions affecting the gut-brain axis. Our findings show that certain disorders elevate AD and PD risk before AD and PD diagnosis including: insulin and non-insulin dependent diabetes mellitus, noninfective gastro-enteritis and colitis, functional intestinal disorders, and bacterial intestinal infections, among others. Polygenic risk scores revealed lower genetic predisposition to AD and PD in individuals with co-occurring disorders in the study categories, underscoring the importance of regulating the gut-brain axis to potentially prevent or delay the onset of neurodegenerative diseases. The proteomic profile of AD/PD cases was influenced by comorbid endocrine, nutritional, metabolic, and digestive systems conditions. Importantly, we developed multi-modal prediction models integrating clinical, genetic, proteomic and demographic data, the combination of which performs better than any single paradigm approach in disease classification. This work aims to illuminate the intricate interplay between various physiological factors involved in the gut-brain axis and the development of AD and PD, providing a multifactorial systemic understanding that goes beyond traditional approaches. Further, we have developed an interactive resource for the scientific community [https://gut-brain-nexus.streamlit.app/] where researchers can investigate components of the predictive model and can investigate feature effects on a sample level.

The evolving pathophysiology of TBI and the advantages of temporally-guided combination therapies

Several clinical and experimental studies have demonstrated that traumatic brain injury (TBI) activates cascades of biochemical, molecular, structural, and pathological changes in the brain. These changes combine to contribute to the various outcomes observed after TBI. Given the breadth and complexity of changes, combination treatments may be an effective approach for targeting multiple detrimental pathways to yield meaningful improvements. In order to identify targets for therapy development, the temporally evolving pathophysiology of TBI needs to be elucidated in detail at both the cellular and molecular levels, as it has been shown that the mechanisms contributing to cognitive dysfunction change over time. Thus, a combination of individual mechanism-based therapies is likely to be effective when maintained based on the time courses of the cellular and molecular changes being targeted. In this review, we will discuss the temporal changes of some of the key clinical pathologies of human TBI, the underlying cellular and molecular mechanisms, and the results from preclinical and clinical studies aimed at mitigating their consequences. As most of the pathological events that occur after TBI are likely to have subsided in the chronic stage of the disease, combination treatments aimed at attenuating chronic conditions such as cognitive dysfunction may not require the initiation of individual treatments at a specific time. We propose that a combination of acute, subacute, and chronic interventions may be necessary to maximally improve health-related quality of life (HRQoL) for persons who have sustained a TBI.

Exposure to Metals, Pesticides, and Air Pollutants: Focus on Resulting DNA Methylation Changes in Neurodegenerative Diseases

Individuals affected by neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are dramatically increasing worldwide. Thus, several efforts are being made to develop strategies for stopping or slowing the spread of these illnesses. Although causative genetic variants linked to the onset of these diseases are known, they can explain only a small portion of cases. The etiopathology underlying the neurodegenerative process in most of the patients is likely due to the interplay between predisposing genetic variants and environmental factors. Epigenetic mechanisms, including DNA methylation, are central candidates in translating the effects of environmental factors in genome modulation, and they play a critical role in the etiology of AD, PD, and ALS. Among the main environmental exposures that have been linked to an increased risk for these diseases, accumulating evidence points to the role of heavy metals, pesticides, and air pollutants. These compounds could trigger neurodegeneration through different mechanisms, mainly neuroinflammation and the induction of oxidative stress. However, increasing evidence suggests that they are also capable of inducing epigenetic alterations in neurons. In this article, we review the available literature linking exposure to metals, pesticides, and air pollutants to DNA methylation changes relevant to neurodegeneration.

In vivo and ex vivo gene therapy for neurodegenerative diseases: a promise for disease modification

Neurodegenerative diseases (NDDs), including AD, PD, HD, and ALS, represent a growing public health concern linked to aging and lifestyle factors, characterized by progressive nervous system damage leading to motor and cognitive deficits. Current therapeutics offer only symptomatic management, highlighting the urgent need for disease-modifying treatments. Gene therapy has emerged as a promising approach, targeting the underlying pathology of diseases with diverse strategies including gene replacement, gene silencing, and gene editing. This innovative therapeutic approach involves introducing functional genetic material to combat disease mechanisms, potentially offering long-term efficacy and disease modification. With advancements in genomics, structural biology, and gene editing tools such as CRISPR/Cas9, gene therapy holds significant promise for addressing the root causes of NDDs. Significant progress in preclinical and clinical studies has demonstrated the potential of in vivo and ex vivo gene therapy to treat various NDDs, offering a versatile and precise approach in comparison to conventional treatments. The current review describes various gene therapy approaches employed in preclinical and clinical studies for the treatment of NDDs, including AD, PD, HD, and ALS, and addresses some of the key translational challenges in this therapeutic approach.

Bisphenol C Induces Cardiac Developmental Defects by Disrupting m6A Homeostasis

Bisphenol A (BPA) is a commonly used plastic additive. Since BPA has been banned in maternal and infant food containers in many countries, BPA substitutes have been widely introduced to replace it. By systematically assessing the potential developmental toxicity of BPA substitutes, we observed that the 41-150 nM in vivo BPC exposure (around the reported concentration detected in infant urine: 6-186 nM) induced cardiac defects in zebrafish. Mechanistically, BPC disrupted m6A homeostasis by downregulation of the key m6A methyltransferase, Mettl3, thereby causing the m6A reader, Igf2bp2b, to fail in recognizing and stabilizing the inefficiently m6A-modified acox1 and tnnt2d mRNA. Then, downregulation of Acox1 (a regulator in cardiac fatty acid metabolism) and Tnnt2d (a component of cardiac troponin for muscle contraction) led to cardiac defects. Indeed, the dual cardiac functional axes regulated by the same m6A reader in response to BPC provided new insight into the regulatory mechanisms of epitranscriptomics and cardiac development. Collectively, our study not only presented evidence showing that the internal exposure levels of BPC in humans could lead to cardiac developmental defects but also demonstrated the underlying mechanism of BPC-mediated defects by disrupting the Mettl3-m6A-Igf2bp2b-Acox1/Tnnt2d pathways, which provided potential molecular markers associated with BPC exposure.

The Microbiota-Gut-Brain Axis and Neurological Disorders: A Comprehensive Review

Microbes have inhabited the earth for hundreds of millions of years longer than humans. The microbiota-gut-brain axis (MGBA) represents a bidirectional communication pathway. These communications occur between the central nervous system (CNS), the enteric nervous system (ENS), and the emotional and cognitive centres of the brain. The field of research on the gut-brain axis has grown significantly during the past two decades. Signalling occurs between the gut microbiota and the brain through the neural, endocrine, immune, and humoral pathways. A substantial body of evidence indicates that the MGBA plays a pivotal role in various neurological diseases. These include Alzheimer's disease (AD), autism spectrum disorder (ASD), Rett syndrome, attention deficit hyperactivity disorder (ADHD), non-Alzheimer's neurodegeneration and dementias, fronto-temporal lobe dementia (FTLD), Wilson-Konovalov disease (WD), multisystem atrophy (MSA), Huntington's chorea (HC), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), temporal lobe epilepsy (TLE), depression, and schizophrenia (SCZ). Furthermore, the bidirectional correlation between therapeutics and the gut-brain axis will be discussed. Conversely, the mood of delivery, exercise, psychotropic agents, stress, and neurologic drugs can influence the MGBA. By understanding the MGBA, it may be possible to facilitate research into microbial-based interventions and therapeutic strategies for neurological diseases.

Integrating amyloid and tau imaging with proteomics and genomics in Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease and is characterized by the aggregation of β-amyloid (Aβ) and tau in the brain. Breakthroughs in disease-modifying treatments targeting Aβ bring new hope for the management of AD. But to effectively modify and someday even prevent AD, a better understanding is needed of the biological mechanisms that underlie and link Aβ and tau in AD. Developments of high-throughput omics, including genomics, proteomics, and transcriptomics, together with molecular imaging of Aβ and tau with positron emission tomography (PET), allow us to discover and understand the biological pathways that regulate the aggregation and spread of Aβ and tau in living humans. The field of integrated omics and PET studies of Aβ and tau in AD is growing rapidly. We here provide an update of this field, both in terms of biological insights and in terms of future clinical implications of integrated omics-molecular imaging studies.

The role of epigenetics in women's reproductive health: the impact of environmental factors

This paper explores the significant role of epigenetics in women's reproductive health, focusing on the impact of environmental factors. It highlights the crucial link between epigenetic modifications-such as DNA methylation and histones post-translational modifications-and reproductive health issues, including infertility and pregnancy complications. The paper reviews the influence of pollutants like PM2.5, heavy metals, and endocrine disruptors on gene expression through epigenetic mechanisms, emphasizing the need for understanding how dietary, lifestyle choices, and exposure to chemicals affect gene expression and reproductive health. Future research directions include deeper investigation into epigenetics in female reproductive health and leveraging gene editing to mitigate epigenetic changes for improving IVF success rates and managing reproductive disorders.

DNA methylation in amyotrophic lateral sclerosis: where do we stand and what is next?

Genes involved in immune response, inflammation and metabolism are among those most likely affected by changes in DNA methylation (DNAm) and expression levels in amyotrophic lateral sclerosis (ALS) tissues. Unfortunately, it is still largely unclear whether any of these changes precede the onset of disease symptoms or whether most of them are the result of the muscular and metabolic changes that follow symptoms onset. In this article the author discusses the strengths and limitations of the available studies of DNAm in ALS and provides some suggestions on what, in his opinion, could be done in the near future for a better understanding of the DNAm changes occurring in ALS, their link with environmental exposures and their potential clinical utility.

Microglial Drivers of Alzheimer's Disease Pathology: An Evolution of Diverse Participating States

Microglia, the resident immune-competent cells of the brain, become dysfunctional in Alzheimer's disease (AD), and their aberrant immune responses contribute to the accumulation of pathological proteins and neuronal injury. Genetic studies implicate microglia in the development of AD, prompting interest in developing immunomodulatory therapies to prevent or ameliorate disease. However, microglia take on diverse functional states in disease, playing both protective and detrimental roles in AD, which largely overlap and may shift over the disease course, complicating the identification of effective therapeutic targets. Extensive evidence gathered using transgenic mouse models supports an active role of microglia in pathology progression, though results vary and can be contradictory between different types of models and the degree of pathology at the time of study. Here, we review microglial immune signaling and responses that contribute to the accumulation and spread of pathological proteins or directly affect neuronal health. We additionally explore the use of induced pluripotent stem cell (iPSC)-derived models to study living human microglia and how they have contributed to our knowledge of AD and may begin to fill in the gaps left by mouse models. Ultimately, mouse and iPSC-derived models have their own limitations, and a comprehensive understanding of microglial dysfunction in AD will only be established by an integrated view across models and an appreciation for their complementary viewpoints and limitations.

Fish consumption, cognitive impairment and dementia: an updated dose-response meta-analysis of observational studies

BACKGROUND

Cognitive impairment is projected to affect a preponderant proportion of the aging population. Lifelong dietary habits have been hypothesized to play a role in preventing cognitive decline. Among the most studied dietary components, fish consumptionhas been extensively studied for its potential effects on the human brain.

AIMS

To perform a meta-analysis of observational studies exploring the association between fish intake and cognitive impairment/decline and all types of dementia.

METHODS

A systematic search of electronic databases was performed to identify observational studies providing quantitative data on fish consumption and outcomes of interest. Random effects models for meta-analyses using only extreme exposure categories, subgroup analyses, and dose-response analyses were performed to estimate cumulative risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

The meta-analysis comprised 35 studies. Individuals reporting the highest vs. the lowest fish consumption were associated with a lower likelihood of cognitive impairment/decline (RR = 0.82, 95% CI: 0.75, 0.90, I2 = 61.1%), dementia (RR = 0.82, 95% CI: 0.73, 0.93, I2 = 38.7%), and Alzheimer's disease (RR = 0.80, 95% CI: 0.67, 0.96, I2 = 20.3%). The dose-response relation revealed a significantly decreased risk of cognitive impairment/decline and all cognitive outcomes across higher levels of fish intake up to 30% for 150 g/d (RR = 0.70, 95% CI: 0.52, 0.95). The results of this relation based on APOE ε4 allele status was mixed based on the outcome investigated.

CONCLUSIONS

Current findings suggest fish consumption is associated with a lower risk of cognitive impairment/decline in a dose-response manner, while for dementia and Alzheimer's disease there is a need for further studies to improve the strength of evidence.

The yield of genetic workup for middle-aged and elderly patients with neurological disorders in a real-world setting

Genetic workup is becoming increasingly common in the clinical assessment of neurological disorders. We evaluated its yield among middle-aged and elderly neurological patients, in a real-world context. This retrospective study included 368 consecutive Israeli patients aged 50 years and older (202 [54.9%] males), who were referred to a single neurogenetics clinic between 2017 and mid-2023. All had neurological disorders, without a previous molecular diagnosis. Demographic, clinical and genetic data were collected from medical records. The mean age at first genetic counseling at the clinic was 62.3 ± 7.8 years (range 50-85 years), and the main indications for referral were neuromuscular, movement and cerebrovascular disorders, as well as cognitive impairment and dementia. Out of the 368 patients, 245 (66.6%) underwent genetic testing that included exome sequencing (ES), analysis of nucleotide repeat expansions, detection of specific mutations, targeted gene panel sequencing or chromosomal microarray analysis. Overall, 80 patients (21.7%) received a molecular diagnosis due to 36 conditions, accounting for 32.7% of the patients who performed genetic testing. The diagnostic rates were highest for neuromuscular (58/186 patients [31.2%] in this group, 39.2% of 148 tested individuals) and movement disorders (14/79 [17.7%] patients, 29.2% of 48 tested), but lower for other disorders. Testing of nucleotide repeat expansions and ES provided a diagnosis to 28/73 (38.4%) and 19/132 (14.4%) individuals, respectively. Based on our findings, genetic workup and testing are useful in the diagnostic process of neurological patients aged ≥50 years, in particular for those with neuromuscular and movement disorders.

Association of birthweight and risk of incident dementia: a prospective cohort study

Given the epidemiological studies investigating the relationship between birthweight and dementia are limited. Our study aimed to explore the association between birthweight and the risk of dementia, cognitive function, and brain structure. We included 275,648 participants from the UK Biobank, categorizing birthweight into quartiles (Q1 ≤ 2.95 kg; Q2 > 2.95 kg, ≤ 3.32 kg; Q3 > 3.32 kg, ≤ 3.66 kg; Q4 > 3.66 kg), with Q3 as the reference. Cox regression models and restricted cubic splines estimated the relationship between birthweight and the risk of all causes of dementia (ACD), Alzheimer's disease (AD), and vascular dementia (VD). Multivariable linear regression models assessed the relationship between birthweight, cognitive function, and MRI biomarkers. Over a median follow-up of 13.0 years, 3103 incident dementia cases were recorded. In the fully adjusted model, compared to Q3 (> 3.32 kg, ≤ 3.66 kg), lower birthweight in Q1 (≤ 2.95 kg) was significantly associated with increased risk of ACD (HR = 1.18, 95%CI 1.06-1.30, P = 0.001) and VD (HR = 1.32, 95%CI 1.07-1.62, P = 0.010), but no significant association with AD was found. Continuous birthweight showed a U-shaped nonlinear association with dementia. Lower birthweight was associated with worse performance in cognitive tasks, including reaction time, fluid intelligence, numeric, and prospective memory. Additionally, certain brain structure indices were identified, including brain atrophy and reductions in area, thickness, and volume of regional subcortical areas. Our study emphasizes the association between lower birthweight and increased dementia risk, correlating cognitive function and MRI biomarkers of brain structure, suggesting that in utero or early-life exposures might impact cognitive health in adulthood.

ALKBH5-mediated N6-methyladenosine modification of HO-1 mRNA regulates ferroptosis in cobalt-induced neurodegenerative damage

The utilization of Cobalt (Co) has surged due to it is critical role in renewable energy technologies and other high-tech applications. Concurrently, the potential health risks associated with Co exposure have raised concerns. Previous studies, including our own, have shown that Co can impair learn and memory functions as an epigenetic hazard, even at low concentrations. In this study, we explore the mechanisms of Co-induced ferroptosis in neurodegenerative damage both in vivo and in vitro, focusing on the epigenetic regulation by N6-methyladenosine (m6A) demethylase alkB homolog 5 (ALKBH5). We identify heme oxygenase-1 (HO-1) as a direct target gene of ALKBH5, playing a crucial role in mitigating Co-induced ferroptosis. ALKBH5 deficiency affects the post-transcriptional regulation of HO-1 through m6A modification, which in turn influences mRNA's stability, intracellular distribution, and alternative splicing, thereby enhancing susceptibility to Co-induced ferroptosis. Additionally, we discuss the potential involvement of heterogeneous nuclear ribonucleoprotein M (hnRNPM) in regulating alternative splicing of HO-1 mRNA, potentially mediated by m6A modifications. This study provides new epigenetic insights into the post-transcriptional regulatory mechanisms involved in Co-induced ferroptosis and highlights the broader implications of environmental hazards in neurodegenerative damage.

A novel derivative of evodiamine improves cognitive impairment and synaptic integrity in AD mice

Alzheimer's disease (AD), the major cause of dementia, is a multifactoral progressive neurodegenerative disorder that currently affects over 43 million people worldwide. The interaction betweengenetic and environmental factors decides pathogenesis and pathological development. The chemical drugs designed for clinical applications on AD have not reached the expected preventive effect so far.Here, we obtained a new evodiamine (Evo) derivative, LE-42, which exhibited lower cytotoxicity in SH-SY5Y cells and HepaG2 cells than that of Evo. The LD50 of LE-42 in SH-SY5Y cells and HepaG2 cells was increased by 9 folds and 14 folds than Evo, respectively. The LE-42 also exhibited much more potent effects on anti-oxidation and anti-cytotoxicity of AβOs than Evo. The LE-42 significantly improved the working memory, spatial learning, and memory of the 3×Tg AD mice, and the pharmacodynamic dose of LE-42 on AD mice was increased by 500 folds than that of Evo. LE-42 significantly improved the Tau hyperphosphorylation, a typical pathological feature in 3×Tg AD mice. The LE-42 restored the JAK2/STAT3 pathway's dysfunction and upregulated the expression of GluN1, GluA2, SYN, and PSD95, subsequentially improving the synaptic integrity in 3×Tg mice. The activation of the JAK2/STAT3 axis by LE-42 was a possible mechanism for a therapeutic effect on the AD mice.

Epigenetics and environmental health

Epigenetic modifications including DNA methylation, histone modifications, chromatin remodeling, and RNA modifications complicate gene regulation and heredity and profoundly impact various physiological and pathological processes. In recent years, accumulating evidence indicates that epigenetics is vulnerable to environmental changes and regulates the growth, development, and diseases of individuals by affecting chromatin activity and regulating gene expression. Environmental exposure or induced epigenetic changes can regulate the state of development and lead to developmental disorders, aging, cardiovascular disease, Alzheimer's disease, cancers, and so on. However, epigenetic modifications are reversible. The use of specific epigenetic inhibitors targeting epigenetic changes in response to environmental exposure is useful in disease therapy. Here, we provide an overview of the role of epigenetics in various diseases. Furthermore, we summarize the mechanism of epigenetic alterations induced by different environmental exposures, the influence of different environmental exposures, and the crosstalk between environmental variation epigenetics, and genes that are implicated in the body's health. However, the interaction of multiple factors and epigenetics in regulating the initiation and progression of various diseases complicates clinical treatments. We discuss some commonly used epigenetic drugs targeting epigenetic modifications and methods to prevent or relieve various diseases regulated by environmental exposure and epigenetics through diet.

Charting Alzheimer's Disease and Dementia: Epidemiological Insights, Risk Factors and Prevention Pathways

Alzheimer's disease (AD), the most common cause of dementia, is a complex and multifactorial condition without cure at present. The latest treatments, based on anti-amyloid monoclonal antibodies, have only a modest effect in reducing the progression of cognitive decline in AD, whereas the possibility of preventing AD has become a crucial area of research. In fact, recent studies have observed a decrease in dementia incidence in developed regions such as the US and Europe. However, these trends have not been mirrored in non-Western countries (Japan or China), and the contributing factors of this reduction remain unclear. The Lancet Commission has delineated a constrained classification of 12 risk factors across different life stages. Nevertheless, the scientific literature has pointed to over 200 factors-including sociodemographic, medical, psychological, and sociocultural conditions-related to the development of dementia/AD. This narrative review aims to synthesize the risk/protective factors of dementia/AD. Essentially, we found that risk/protective factors vary between individuals and populations, complicating the creation of a unified prevention strategy. Moreover, dementia/AD explanatory mechanisms involve a diverse array of genetic and environmental factors that interact from the early stages of life. In the future, studies across different population-based cohorts are essential to validate risk/protective factors of dementia. This evidence would help develop public health policies to decrease the incidence of dementia.

Variations in the LINGO2 and GLIS3 Genes and Gene-Environment Interactions Increase Gestational Diabetes Mellitus Risk in Chinese Women

Gestational diabetes mellitus (GDM) has been found to be a common complication in pregnant women, known to escalate the risk of negative obstetric outcomes. In our study, we genotyped 1,566 Chinese pregnant women for two single nucleotide polymorphisms (SNPs) in the LINGO2 gene and one SNP in the GLIS3 gene, utilizing targeted next-generation sequencing. The impact of two interacting genes, and the interaction of genes with the environment─including exposure to particulate matter (PM2.5), ozone (O3), and variations in prepregnancy body mass index (BMI)─on the incidence of GDM were analyzed using logistic regression. Our findings identify the variants LINGO2 rs10968576 (P = 0.022, OR = 1.224) and rs1412239 (P = 0.018, OR = 1.231), as well as GLIS3 rs10814916 (P = 0.028, OR = 1.172), as risk mutations significantly linked to increased susceptibility to GDM. Further analysis underscores the crucial role of gene-gene and gene-environment interactions in the development of GDM among Chinese women (P < 0.05). Particularly, the individuals carrying the rs10968576 G-rs1412239 G-rs10814916 C haplotype exhibit increased susceptibility to GDM during the prepregnancy period when interacting with PM2.5, O3, and BMI (P = 8.004 × 10-7, OR = 1.206; P = 6.3264 × 10-11, OR = 1.280; P = 9.928 × 10-7, OR = 1.334, respectively). In conclusion, our research emphasizes the importance of the interaction between specific gene variations─LINGO2 and GLIS3─and environmental factors in influencing GDM risk. Notably, we found significant associations between these gene variations and GDM risk across various environmental exposure periods.

Antioxidant, anti-inflammatory and epigenetic potential of curcumin in Alzheimer's disease

Alzheimer's disease (AD) constitutes a multifactorial neurodegenerative pathology characterized by cognitive deterioration, personality alterations, and behavioral shifts. The ongoing brain impairment process poses significant challenges for therapeutic interventions due to activating multiple neurotoxic pathways. Current pharmacological interventions have shown limited efficacy and are associated with significant side effects. Approaches focusing on the early interference with disease pathways, before activation of broad neurotoxic processes, could be promising to slow down symptomatic progression of the disease. Curcumin-an integral component of traditional medicine in numerous cultures worldwide-has garnered interest as a promising AD treatment. Current research indicates that curcumin may exhibit therapeutic potential in neurodegenerative pathologies, attributed to its potent anti-inflammatory and antioxidant properties. Additionally, curcumin and its derivatives have demonstrated an ability to modulate cellular pathways via epigenetic mechanisms. This article aims to raise awareness of the neuroprotective properties of curcuminoids that could provide therapeutic benefits in AD. The paper provides a comprehensive overview of the neuroprotective efficacy of curcumin against signaling pathways that could be involved in AD and summarizes recent evidence of the biological efficiency of curcumins in vivo.

Associations of Heavy Metals with Cognitive Function: An Epigenome-Wide View of DNA Methylation and Mediation Analysis

OBJECTIVE

Exposure to heavy metals has been reported to be associated with impaired cognitive function, but the underlying mechanisms remain unclear. This pilot study aimed to identify key heavy metal elements associated with cognitive function and further explore the potential mediating role of metal-related DNA methylation.

METHODS

Blood levels of arsenic, cadmium, lead, copper, manganese, and zinc and genome-wide DNA methylations were separately detected in peripheral blood in 155 older adults. Cognitive function was evaluated using the Mini-Mental State Examination (MMSE). Least absolute shrinkage and selection operator penalized regression and Bayesian kernel machine regression were used to identify metals associated with cognitive function. An epigenome-wide association study examined the DNA methylation profile of the identified metal, and mediation analysis investigated its mediating role.

RESULTS

The MMSE scores showed a significant decrease of 1.61 (95% confidence interval [CI]: -2.64, -0.59) with each 1 standard deviation increase in ln-transformed arsenic level; this association was significant in multiple-metal models and dominated the overall negative effect of 6 heavy metal mixture on cognitive function. Seventy-three differentially methylated positions were associated with blood arsenic (p < 1.0 × 10-5). The methylation levels at cg05226051 (annotated to TDRD3) and cg18886932 (annotated to GAL3ST3) mediated 24.8% and 25.5% of the association between blood arsenic and cognitive function, respectively (all p < 0.05).

INTERPRETATION

Blood arsenic levels displayed a negative association with the cognitive function of older adults. This finding shows that arsenic-related DNA methylation alterations are critical partial mediators that may serve as potential biomarkers for further mechanism-related studies. ANN NEUROL 2024;96:87-98.

Apolipoprotein E in Alzheimer's disease trajectories and the next-generation clinical care pathway

Alzheimer's disease (AD) is a complex, progressive primary neurodegenerative disease. Since pivotal genetic studies in 1993, the ε4 allele of the apolipoprotein E gene (APOE ε4) has remained the strongest single genome-wide associated risk variant in AD. Scientific advances in APOE biology, AD pathophysiology and ApoE-targeted therapies have brought APOE to the forefront of research, with potential translation into routine AD clinical care. This contemporary Review will merge APOE research with the emerging AD clinical care pathway and discuss APOE genetic risk as a conduit to genomic-based precision medicine in AD, including ApoE's influence in the ATX(N) biomarker framework of AD. We summarize the evidence for APOE as an important modifier of AD clinical-biological trajectories. We then illustrate the utility of APOE testing and the future of ApoE-targeted therapies in the next-generation AD clinical-diagnostic pathway. With the emergence of new AD therapies, understanding how APOE modulates AD pathophysiology will become critical for personalized AD patient care.