ABSTRACT
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protein that regulates cholesterol levels by lysosomal low-density lipoprotein receptor (LDLR) degradation and has recently been associated with the production of neuronal oxidative stress and age-associated cardiovascular dysfunction. Since increased oxidative stress and vascular dysfunction are implicated in the pathology of aging and various neurodegenerative disorders, targeting PCSK9 may offer a promising therapeutic avenue for addressing these conditions. While the precise mechanisms through which PCSK9 contributes to vascular and neuronal oxidative stress in the brain remain elusive, preclinical studies have highlighted a neuroprotective effect linked to PCSK9 inhibition. This inhibition has shown promise in reducing oxidative stress, mitigating neuroinflammation, and alleviating neuropathological changes, thus underscoring the therapeutic potential of this approach in addressing neurodegenerative conditions.
Subject(s)
Neurodegenerative Diseases , Oxidative Stress , PCSK9 Inhibitors , Proprotein Convertase 9 , Humans , Oxidative Stress/drug effects , Oxidative Stress/physiology , Neurodegenerative Diseases/metabolism , Neurodegenerative Diseases/drug therapy , Animals , Proprotein Convertase 9/metabolism , Neuroprotective Agents/pharmacologyABSTRACT
Importance: Observational studies suggest that major psychiatric disorders and substance use behaviors reduce longevity, making it difficult to disentangle their relationships with aging-related outcomes. Objective: To evaluate the associations between the genetic liabilities for major psychiatric disorders, substance use behaviors (smoking and alcohol consumption), and longevity. Design, Settings, and Participants: This 2-sample mendelian randomization (MR) study assessed associations between psychiatric disorders, substance use behaviors, and longevity using single-variable and multivariable models. Multiomics analyses were performed elucidating transcriptomic underpinnings of the MR associations and identifying potential proteomic therapeutic targets. This study sourced summary-level genome-wide association study (GWAS) data, gene expression, and proteomic data from cohorts of European ancestry. Analyses were performed from May 2022 to November 2023. Exposures: Genetic susceptibility for major depression (n = 500â¯199), bipolar disorder (n = 413â¯466), schizophrenia (n = 127â¯906), problematic alcohol use (n = 435â¯563), weekly alcohol consumption (n = 666â¯978), and lifetime smoking index (n = 462â¯690). Main Outcomes and Measures: The main outcome encompassed aspects of health span, lifespan, and exceptional longevity. Additional outcomes were epigenetic age acceleration (EAA) clocks. Results: Findings from multivariable MR models simultaneously assessing psychiatric disorders and substance use behaviorsm suggest a negative association between smoking and longevity in cohorts of European ancestry (n = 709â¯709; 431â¯503 [60.8%] female; ß, -0.33; 95% CI, -0.38 to -0.28; P = 4.59 × 10-34) and with increased EAA (n = 34â¯449; 18â¯017 [52.3%] female; eg, PhenoAge: ß, 1.76; 95% CI, 0.72 to 2.79; P = 8.83 × 10-4). Transcriptomic imputation and colocalization identified 249 genes associated with smoking, including 36 novel genes not captured by the original smoking GWAS. Enriched pathways included chromatin remodeling and telomere assembly and maintenance. The transcriptome-wide signature of smoking was inversely associated with longevity, and estimates of individual smoking-associated genes, eg, XRCC3 and PRMT6, aligned with the smoking-longevity MR analyses, suggesting underlying transcriptomic mediators. Cis-instrument MR prioritized brain proteins associated with smoking behavior, including LY6H (ß, 0.02; 95% CI, 0.01 to 0.03; P = 2.37 × 10-6) and RIT2 (ß, 0.02; 95% CI, 0.01 to 0.03; P = 1.05 × 10-5), which had favorable adverse-effect profiles across 367 traits evaluated in phenome-wide MR. Conclusions: The findings suggest that the genetic liability of smoking, but not of psychiatric disorders, is associated with longevity. Transcriptomic associations offer insights into smoking-related pathways, and identified proteomic targets may inform therapeutic development for smoking cessation strategies.
Subject(s)
Genome-Wide Association Study , Longevity , Mendelian Randomization Analysis , Humans , Longevity/genetics , Female , Male , Smoking/epidemiology , Smoking/genetics , Substance-Related Disorders/genetics , Substance-Related Disorders/epidemiology , Depressive Disorder, Major/genetics , Depressive Disorder, Major/epidemiology , Genetic Predisposition to Disease/genetics , Schizophrenia/genetics , Schizophrenia/epidemiology , Mental Disorders/genetics , Mental Disorders/epidemiology , Bipolar Disorder/genetics , Bipolar Disorder/epidemiology , Alcohol Drinking/genetics , Alcohol Drinking/epidemiology , Aged , Middle AgedABSTRACT
Alcohol Use Disorder (AUD) is a persistent condition linked to neuroinflammation, neuronal oxidative stress, and neurodegenerative processes. While the inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) has demonstrated effectiveness in reducing liver inflammation associated with alcohol, its impact on the brain remains largely unexplored. This study aimed to assess the effects of alirocumab, a monoclonal antibody targeting PCSK9 to lower systemic low-density lipoprotein cholesterol (LDL-C), on central nervous system (CNS) pathology in a rat model of chronic alcohol exposure. Alirocumab (50 mg/kg) or vehicle was administered weekly for six weeks in 32 male rats subjected to a 35 % ethanol liquid diet or a control liquid diet (n = 8 per group). The study evaluated PCSK9 expression, LDL receptor (LDLR) expression, oxidative stress, and neuroinflammatory markers in brain tissues. Chronic ethanol exposure increased PCSK9 expression in the brain, while alirocumab treatment significantly upregulated neuronal LDLR and reduced oxidative stress in neurons and brain vasculature (3-NT, p22phox). Alirocumab also mitigated ethanol-induced microglia recruitment in the cortex and hippocampus (Iba1). Additionally, alirocumab decreased the expression of pro-inflammatory cytokines and chemokines (TNF, CCL2, CXCL3) in whole brain tissue and attenuated the upregulation of adhesion molecules in brain vasculature (ICAM1, VCAM1, eSelectin). This study presents novel evidence that alirocumab diminishes oxidative stress and modifies neuroimmune interactions in the brain elicited by chronic ethanol exposure. Further investigation is needed to elucidate the mechanisms by which PCSK9 signaling influences the brain in the context of chronic ethanol exposure.
Subject(s)
Antibodies, Monoclonal, Humanized , Brain , Ethanol , Neurons , Oxidative Stress , PCSK9 Inhibitors , Proprotein Convertase 9 , Animals , Oxidative Stress/drug effects , Male , Rats , Neurons/metabolism , Neurons/drug effects , PCSK9 Inhibitors/pharmacology , Proprotein Convertase 9/metabolism , Brain/metabolism , Brain/drug effects , Antibodies, Monoclonal, Humanized/pharmacology , Alcoholism/metabolism , Alcoholism/drug therapy , Microglia/metabolism , Microglia/drug effects , Receptors, LDL/metabolism , Rats, Sprague-Dawley , Disease Models, AnimalABSTRACT
BACKGROUND: Alcohol use disorder (AUD) is associated with increased mortality and morbidity risk. A reason for this could be accelerated biological aging, which is strongly influenced by disease processes such as inflammation. As recent studies of AUD show changes in DNA methylation and gene expression in neuroinflammation-related pathways in the brain, biological aging represents a potentially important construct for understanding the adverse effects of substance use disorders. Epigenetic clocks have shown accelerated aging in blood samples from individuals with AUD. However, no systematic evaluation of biological age measures in AUD across different tissues and brain regions has been undertaken. METHODS: As markers of biological aging (BioAge markers), we assessed Levine's and Horvath's epigenetic clocks, DNA methylation telomere length (DNAmTL), telomere length (TL), and mitochondrial DNA copy number (mtDNAcn) in postmortem brain samples from Brodmann Area 9 (BA9), caudate nucleus, and ventral striatum (N = 63-94), and in whole blood samples (N = 179) of individuals with and without AUD. To evaluate the association between AUD status and BioAge markers, we performed linear regression analyses while adjusting for covariates. RESULTS: The majority of BioAge markers were significantly associated with chronological age in all samples. Levine's epigenetic clock and DNAmTL were indicative of accelerated biological aging in AUD in BA9 and whole blood samples, while Horvath's showed the opposite effect in BA9. No significant association of AUD with TL and mtDNAcn was detected. Measured TL and DNAmTL showed only small correlations in blood and none in brain. CONCLUSIONS: The present study is the first to simultaneously investigate epigenetic clocks, telomere length, and mtDNAcn in postmortem brain and whole blood samples in individuals with AUD. We found evidence for accelerated biological aging in AUD in blood and brain, as measured by Levine's epigenetic clock, and DNAmTL. Additional studies of different tissues from the same individuals are needed to draw valid conclusions about the congruence of biological aging in blood and brain.
Subject(s)
Hydroxymethylglutaryl-CoA Reductase Inhibitors , PCSK9 Inhibitors , Humans , East Asian People , Heart , Hydroxymethylglutaryl CoA Reductases/genetics , Mendelian Randomization Analysis , Proprotein Convertase 9/genetics , European People , PCSK9 Inhibitors/therapeutic use , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic useABSTRACT
BACKGROUND & AIMS: Observational studies have linked lipid-lowering drug targets pro-protein convertase subtilisin/kexin 9 (PCSK9) and HMG-CoA reductase (HMGCR) with adverse liver outcomes; however, liver disease incidence varies across diverse populations, and the long-term hepatic impact of these lipid-lowering drugs among non-white Europeans remains largely unknown. METHODS: We use single nucleotide polymorphisms (SNPs) in PCSK9 and HMGCR loci from genome-wide association study data of low-density lipoprotein cholesterol in 4 populations (East Asian [EAS], South Asian [SAS], African [AFR], and European [EUR]) to perform drug-target Mendelian randomization investigating relationships between PCSK9 and HMGCR inhibition and alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and bilirubin. RESULTS: Analyses of PCSK9 instruments, including functional variants R46L and E670G, failed to find evidence for relationships of low-density lipoprotein cholesterol lowering via PCSK9 variants and adverse effects on ALT, AST, GGT, or ALP among the cohorts. PCSK9 inhibition was associated with increased direct bilirubin levels in EUR (ß = 0.089; P value = 5.69 × 10-6) and, nominally, in AFR (ß = 0.181; P value = .044). HMGCR inhibition was associated with reduced AST in SAS (ß = -0.705; P value = .005) and, nominally, reduced AST in EAS (ß = -0.096; P value = .03), reduced ALP in EUR (ß = -2.078; P value = .014), and increased direct bilirubin in EUR (ß = 0.071; P value = .032). Sensitivity analyses using genetic instruments derived from circulating PCSK9 protein levels, tissue-specific PCSK9 expression, and HMGCR expression were in alignment, strengthening causal inference. CONCLUSIONS: We did not find ALT, AST, GGT, or ALP associated with genetically proxied PCSK9 and HMGCR inhibition across ancestries. We identified possible relationships in several ancestries between PCSK9 and increased direct and total bilirubin and between HMGCR and reduced AST. These findings support long-term safety profiles and low hepatotoxic risk of PCSK9 and HMGCR inhibition in diverse populations.
Subject(s)
Proprotein Convertase 9 , Subtilisin , Humans , Proprotein Convertase 9/genetics , Genome-Wide Association Study , Mendelian Randomization Analysis , Liver , Bilirubin , Lipoproteins, LDL , Cholesterol , Lipids , Hydroxymethylglutaryl CoA Reductases/geneticsABSTRACT
Cardiovascular diseases (CVDs) are the leading cause of death among elderly people. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an important regulator of cholesterol metabolism. Herein, we investigated the role of PCSK9 in age-related CVD. Both in humans and rats, blood PCSK9 level correlated positively with increasing age and the development of cardiovascular dysfunction. Age-related fatty degeneration of liver tissue positively correlated with serum PCSK9 levels in the rat model, while development of age-related nonalcoholic fatty liver disease correlated with cardiovascular functional impairment. Network analysis identified PCSK9 as an important factor in age-associated lipid alterations and it correlated positively with intima-media thickness, a clinical parameter of CVD risk. PCSK9 inhibition with alirocumab effectively reduced the CVD progression in aging rats, suggesting that PCSK9 plays an important role in cardiovascular aging.
ABSTRACT
Excessive alcohol consumption has detrimental effects on the entire organism, especially on the liver. The toxicity is partly dependent on age, as older individuals metabolize alcohol more slowly leading to increased cellular injury. This study aimed to investigate the effects of moderate binge drinking on the liver of young and aged mice in a genome-wide multi-omics approach. We determined DNA methylation (DNAm) using the Illumina MouseMethylation array and gene expression by RNA sequencing in 18 female Balb/c mice in a 2 × 2 design. The animals underwent three moderate binge drinking cycles (ethanol vs. vehicle) and liver tissue was harvested at 4 or 19 months of age. We tested differential gene expression (DE) and DNAm associated with ethanol intake in linear models separately in young and aged mice, performed enrichment analyses for pathways and GWAS signatures of problematic alcohol use, and analysed the overlap of DNAm and gene expression. We observed DE in young and aged animals and substantial overlap in genes such as Bhlhe40, Klf10, and Frmd8. DE genes in aged animals were enriched for biological processes related to alcohol metabolism, inflammation, liver fibrosis, and GWAS signatures of problematic alcohol use. We identified overlapping signatures from DNAm and gene expression, for example, Frmd8 in aged and St6galnac4 in young mice. This study offers converging evidence of novel age-related targets in a moderate alcohol consumption model highlighting dysregulations in genes related to alcohol metabolism, inflammation, and liver fibrosis. Future studies are needed to confirm these results and elucidate the underlying mechanisms.
Subject(s)
Binge Drinking , Female , Animals , Mice , Binge Drinking/genetics , Binge Drinking/metabolism , Multiomics , Ethanol/pharmacology , Alcohol Drinking/genetics , Inflammation , Liver CirrhosisABSTRACT
The liver, as a crucial metabolic organ, undergoes significant pathological changes during the aging process, which can have a profound impact on overall health. To gain a comprehensive understanding of these alterations, we employed data-driven approaches, along with biochemical methods, histology, and immunohistochemistry techniques, to systematically investigate the effects of aging on the liver. Our study utilized a well-established rat aging model provided by the National Institute of Aging. Systems biology approaches were used to analyze genome-wide transcriptomics data from liver samples obtained from young (4-5 months old) and aging (20-21 months old) Fischer 344 rats. Our findings revealed pathological changes occurring in various essential biological processes in aging livers. These included mitochondrial dysfunction, increased oxidative/nitrative stress, decreased NAD + content, impaired amino acid and protein synthesis, heightened inflammation, disrupted lipid metabolism, enhanced apoptosis, senescence, and fibrosis. These results were validated using independent datasets from both human and rat aging studies. Furthermore, by employing co-expression network analysis, we identified novel driver genes responsible for liver aging, confirmed our findings in human aging subjects, and pointed out the cellular localization of the driver genes using single-cell RNA-sequencing human data. Our study led to the discovery and validation of a liver-specific gene, proprotein convertase subtilisin/kexin type 9 (PCSK9), as a potential therapeutic target for mitigating the pathological processes associated with aging in the liver. This finding envisions new possibilities for developing interventions aimed to improve liver health during the aging process.
Subject(s)
Proprotein Convertase 9 , Transcriptome , Humans , Rats , Animals , Proprotein Convertase 9/genetics , Proprotein Convertase 9/metabolism , Liver/metabolism , Aging/geneticsABSTRACT
The concept of aging is complex, including many related phenotypes such as healthspan, lifespan, extreme longevity, frailty and epigenetic aging, suggesting shared biological underpinnings; however, aging-related endpoints have been primarily assessed individually. Using data from these traits and multivariate genome-wide association study methods, we modeled their underlying genetic factor ('mvAge'). mvAge (effective n = ~1.9 million participants of European ancestry) identified 52 independent variants in 38 genomic loci. Twenty variants were novel (not reported in input genome-wide association studies). Transcriptomic imputation identified age-relevant genes, including VEGFA and PHB1. Drug-target Mendelian randomization with metformin target genes showed a beneficial impact on mvAge (P value = 8.41 × 10-5). Similarly, genetically proxied thiazolidinediones (P value = 3.50 × 10-10), proprotein convertase subtilisin/kexin 9 inhibition (P value = 1.62 × 10-6), angiopoietin-like protein 4, beta blockers and calcium channel blockers also had beneficial Mendelian randomization estimates. Extending the drug-target Mendelian randomization framework to 3,947 protein-coding genes prioritized 122 targets. Together, these findings will inform future studies aimed at improving healthy aging.
Subject(s)
Genome-Wide Association Study , Healthy Aging , Phenotype , LongevityABSTRACT
Biological aging is accompanied by increasing morbidity, mortality, and healthcare costs; however, its molecular mechanisms are poorly understood. Here, we use multi-omic methods to integrate genomic, transcriptomic, and metabolomic data and identify biological associations with four measures of epigenetic age acceleration and a human longevity phenotype comprising healthspan, lifespan, and exceptional longevity (multivariate longevity). Using transcriptomic imputation, fine-mapping, and conditional analysis, we identify 22 high confidence associations with epigenetic age acceleration and seven with multivariate longevity. FLOT1, KPNA4, and TMX2 are novel, high confidence genes associated with epigenetic age acceleration. In parallel, cis-instrument Mendelian randomization of the druggable genome associates TPMT and NHLRC1 with epigenetic aging, supporting transcriptomic imputation findings. Metabolomics Mendelian randomization identifies a negative effect of non-high-density lipoprotein cholesterol and associated lipoproteins on multivariate longevity, but not epigenetic age acceleration. Finally, cell-type enrichment analysis implicates immune cells and precursors in epigenetic age acceleration and, more modestly, multivariate longevity. Follow-up Mendelian randomization of immune cell traits suggests lymphocyte subpopulations and lymphocytic surface molecules affect multivariate longevity and epigenetic age acceleration. Our results highlight druggable targets and biological pathways involved in aging and facilitate multi-omic comparisons of epigenetic clocks and human longevity.
Subject(s)
Longevity , Multiomics , Humans , Longevity/genetics , Epigenesis, Genetic , Aging/genetics , Phenotype , Lipoproteins/genetics , DNA Methylation/genetics , Ubiquitin-Protein Ligases/genetics , alpha Karyopherins/geneticsABSTRACT
The gene encoding proprotein convertase subtilisin/kexin type 9 (PCSK9) and its protein product have been widely studied for their role in cholesterol and lipid metabolism. PCSK9 increases the rate of metabolic degradation of low-density lipoprotein receptors, preventing the diffusion of low-density lipoprotein (LDL) from plasma into cells and contributes to high lipoprotein-bound cholesterol levels in the plasma. While most research has focused on the regulation and disease relevance of PCSK9 to the cardiovascular system and lipid metabolism, there is a growing body of evidence that PCSK9 plays a crucial role in pathogenic processes in other organ systems, including the central nervous system. PCSK9's impact on the brain is not yet fully understood, though several recent studies have sought to illuminate its impact on various neurodegenerative and psychiatric disorders, as well as its connection with ischemic stroke. Cerebral PCSK9 expression is low but is highly upregulated during disease states. Among others, PCSK9 is known to play a role in neurogenesis, neural cell differentiation, central LDL receptor metabolism, neural cell apoptosis, neuroinflammation, Alzheimer's Disease, Alcohol Use Disorder, and stroke. The PCSK9 gene contains several polymorphisms, including both gain-of-function and loss-of-function mutations which profoundly impact normal PCSK9 signaling and cholesterol metabolism. Gain-of-function mutations lead to persistent hypercholesterolemia and poor health outcomes, while loss-of-function mutations generally lead to hypocholesterolemia and may serve as a protective factor against diseases of the liver, cardiovascular system, and central nervous system. Recent genomic studies have sought to identify the end-organ effects of such mutations and continue to identify evidence of a much broader role for PCSK9 in extrahepatic organ systems. Despite this, there remain large gaps in our understanding of PCSK9, its regulation, and its effects on disease risk outside the liver. This review, which incorporates data from a wide range of scientific disciplines and experimental paradigms, is intended to describe PCSK9's role in the central nervous system as it relates to cerebral disease and neuropsychiatric disorders, and to examine the clinical potential of PCSK9 inhibitors and genetic variation in the PCSK9 gene on disease outcomes, including neurological and neuropsychiatric disease.
Subject(s)
Lipoproteins, LDL , Proprotein Convertase 9 , Humans , Proprotein Convertase 9/genetics , Proprotein Convertase 9/metabolism , Lipoproteins, LDL/metabolism , Brain/metabolism , Subtilisins/metabolismABSTRACT
Lithium (Li) is one of the most effective drugs for treating bipolar disorder (BD), however, there is presently no way to predict response to guide treatment. The aim of this study is to identify functional genes and pathways that distinguish BD Li responders (LR) from BD Li non-responders (NR). An initial Pharmacogenomics of Bipolar Disorder study (PGBD) GWAS of lithium response did not provide any significant results. As a result, we then employed network-based integrative analysis of transcriptomic and genomic data. In transcriptomic study of iPSC-derived neurons, 41 significantly differentially expressed (DE) genes were identified in LR vs NR regardless of lithium exposure. In the PGBD, post-GWAS gene prioritization using the GWA-boosting (GWAB) approach identified 1119 candidate genes. Following DE-derived network propagation, there was a highly significant overlap of genes between the top 500- and top 2000-proximal gene networks and the GWAB gene list (Phypergeometric = 1.28E-09 and 4.10E-18, respectively). Functional enrichment analyses of the top 500 proximal network genes identified focal adhesion and the extracellular matrix (ECM) as the most significant functions. Our findings suggest that the difference between LR and NR was a much greater effect than that of lithium. The direct impact of dysregulation of focal adhesion on axon guidance and neuronal circuits could underpin mechanisms of response to lithium, as well as underlying BD. It also highlights the power of integrative multi-omics analysis of transcriptomic and genomic profiling to gain molecular insights into lithium response in BD.
ABSTRACT
BACKGROUND: Stress contributes to premature aging and susceptibility to alcohol use disorder (AUD), and AUD itself is a factor in premature aging; however, the interrelationships of stress, AUD, and premature aging are poorly understood. METHODS: We constructed a composite score of stress from 13 stress-related outcomes in a discovery cohort of 317 individuals with AUD and control subjects. We then developed a novel methylation score of stress (MS stress) as a proxy of composite score of stress comprising 211 CpGs selected using a penalized regression model. The effects of MS stress on health outcomes and epigenetic aging were assessed in a sample of 615 patients with AUD and control subjects using epigenetic clocks and DNA methylation-based telomere length. Statistical analysis with an additive model using MS stress and a MS for alcohol consumption (MS alcohol) was conducted. Results were replicated in 2 independent cohorts (Generation Scotland, N = 7028 and the Grady Trauma Project, N = 795). RESULTS: Composite score of stress and MS stress were strongly associated with heavy alcohol consumption, trauma experience, epigenetic age acceleration (EAA), and shortened DNA methylation-based telomere length in AUD. Together, MS stress and MS alcohol additively showed strong stepwise increases in EAA. Replication analyses showed robust association between MS stress and EAA in the Generation Scotland and Grady Trauma Project cohorts. CONCLUSIONS: A methylation-derived score tracking stress exposure is associated with various stress-related phenotypes and EAA. Stress and alcohol have additive effects on aging, offering new insights into the pathophysiology of premature aging in AUD and, potentially, other aspects of gene dysregulation in this disorder.
Subject(s)
Aging, Premature , Alcoholism , Humans , Alcoholism/genetics , Aging, Premature/genetics , Alcohol Drinking/genetics , DNA Methylation , Epigenesis, GeneticABSTRACT
Individuals with genetic gain-of-function variation in the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene are at an increased risk of cardiovascular disease, including ischemic stroke. While PCSK9 inhibitors (PCSK9i) are effective in reducing cardiovascular disease risk and ischemic stroke risk, novel genomic technologies including the use of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 complex-mediated delivery and adenine base editing (ABE) enable promising new therapeutic and preventative approaches. In this paper we discuss ongoing work into PCSK9 base editing and highlight future directions relevant to cardiovascular disease and ischemic stroke.
Subject(s)
Cardiovascular Diseases , Ischemic Stroke , Humans , Proprotein Convertase 9/genetics , Gene EditingABSTRACT
Background PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors are important therapeutic options for reducing cardiovascular disease risk; however, questions remain regarding potential differences in the neuropsychiatric impact of long-term PCSK9 inhibition between men and women. Methods and Results Using PCSK9 gene single-nucleotide polymorphisms from European ancestry-based genome-wide association studies of low-density lipoprotein cholesterol (N=1 320 016), circulating PCSK9 protein levels (N=10 186), tissue-specific PCSK9 gene expression, sex-specific genome-wide association studies of anxiety, depression, cognition, insomnia, and dementia (ranging from 54 321 to 194 174), we used drug-target inverse variance-weighted Mendelian randomization (MR) and complementary MR methods (MR Egger, weighted median, and weighted mode) to investigate potential neuropsychiatric consequences of genetically proxied PCSK9 inhibition in men and women. We failed to find evidence surpassing correction for multiple comparisons of relationships between genetically proxied PCSK9 inhibition and the risk for the 12 neuropsychiatric end points in either men or women. Drug-target analyses were generally well-powered to detect effect estimates at several hypothesized thresholds for both combined-sex and sex-specific end points, especially analyses using PCSK9 instruments derived from protein and expression quantitative trait loci. Further, MR estimates across complementary MR methods and additional models using genetic instruments derived from circulating PCSK9 protein levels and tissue-specific PCSK9 expression were in alignment, strengthening causal inference. Conclusions Genetically proxied PCSK9 inhibition showed a neutral neuropsychiatric side effect profile with no major sex-specific differences. Given statistical power considerations, replication with larger samples, as well as data from other ancestral populations, are necessary. These findings may have important clinical implications for lipid-lowering drug-prescribing practices and side effect monitoring of approved and future PCSK9 therapies.
Subject(s)
Cognition Disorders , Dementia , Mood Disorders , Proprotein Convertase 9 , Female , Humans , Male , Cognition , Cognition Disorders/genetics , Dementia/genetics , Genome-Wide Association Study , Mendelian Randomization Analysis , Mood Disorders/genetics , Proprotein Convertase 9/genetics , Proprotein Convertase 9/metabolismABSTRACT
Importance: Past studies have identified associations between brain macrostructure and alcohol use behaviors. However, identifying directional associations between these phenotypes is difficult due to the limitations of observational studies. Objective: To use mendelian randomization (MR) to identify directional associations between brain structure and alcohol use and elucidate the transcriptomic and cellular underpinnings of identified associations. Design, Setting, and Participants: The main source data comprised summary statistics from population-based and case-control genome-wide association studies (GWAS) of neuroimaging, behavioral, and clinical phenotypes (N = 763â¯874). Using these data, bidirectional and multivariable MR was performed analyzing associations between brain macrostructure and alcohol use. Downstream transcriptome-wide association studies (TWAS) and cell-type enrichment analyses investigated the biology underlying identified associations. The study approach was data driven and did not test any a priori hypotheses. Data were analyzed August 2021 to May 2022. Main Outcomes and Measures: Brain structure phenotypes (global cortical thickness [GCT] and global cortical surface area [GCSA] in 33â¯709 individuals and left-right subcortical volumes in 19â¯629 individuals) and alcohol use behaviors (alcoholic drinks per week [DPW] in 537â¯349 individuals, binge drinking frequency in 143â¯685 individuals, and alcohol use disorder in 8845 individuals vs 20â¯657 control individuals [total of 29â¯502]). Results: The main bidirectional MR analyses were performed in samples totaling 763â¯874 individuals, among whom more than 94% were of European ancestry, 52% to 54% were female, and the mean cohort ages were 40 to 63 years. Negative associations were identified between genetically predicted GCT and binge drinking (ß, -2.52; 95% CI, -4.13 to -0.91) and DPW (ß, -0.88; 95% CI, -1.37 to -0.40) at a false discovery rate (FDR) of 0.05. These associations remained significant in multivariable MR models that accounted for neuropsychiatric phenotypes, substance use, trauma, and neurodegeneration. TWAS of GCT and alcohol use behaviors identified 5 genes at the 17q21.31 locus oppositely associated with GCT and binge drinking or DPW (FDR = 0.05). Cell-type enrichment analyses implicated glutamatergic cortical neurons in alcohol use behaviors. Conclusions and Relevance: The findings in this study show that the associations between GCT and alcohol use may reflect a predispositional influence of GCT and that 17q21.31 genes and glutamatergic cortical neurons may play a role in this association. While replication studies are needed, these findings should enhance the understanding of associations between brain structure and alcohol use.
Subject(s)
Binge Drinking , Mendelian Randomization Analysis , Alcohol Drinking/genetics , Brain/diagnostic imaging , Ethanol , Female , Genome-Wide Association Study , Humans , Male , Mendelian Randomization Analysis/methods , Polymorphism, Single Nucleotide/geneticsABSTRACT
BACKGROUND: Lipid-lowering therapy with statins and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition are effective strategies in reducing cardiovascular disease risk; however, concerns remain about potential long-term adverse neurocognitive effects. OBJECTIVES: This genetics-based study aimed to evaluate the relationships of long-term PCSK9 inhibition and statin use on neurocognitive outcomes. METHODS: We extracted single-nucleotide polymorphisms in 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and PCSK9 from predominantly European ancestry-based genome-wide association studies summary-level statistics of low-density lipoprotein cholesterol and performed drug-target Mendelian randomization, proxying the potential neurocognitive impact of drug-based PCSK9 and HMGCR inhibition using a range of outcomes to capture the complex facets of cognition and dementia. RESULTS: Using data from a combined sample of â¼740,000 participants, we observed a neutral cognitive profile related to genetic PCSK9 inhibition, with no significant effects on cognitive performance, memory performance, or cortical surface area. Conversely, we observed several adverse associations for HMGCR inhibition with lowered cognitive performance (beta: -0.082; 95% CI: -0.16 to -0.0080; P = 0.03), reaction time (beta = 0.00064; 95% CI: 0.00030-0.00098; P = 0.0002), and cortical surface area (beta = -0.18; 95% CI: -0.35 to -0.014; P = 0.03). Neither PCSK9 nor HMGCR inhibition impacted biomarkers of Alzheimer's disease progression or Lewy body dementia risk. Consistency of findings across Mendelian randomization methods accommodating different assumptions about genetic pleiotropy strengthens causal inference. CONCLUSIONS: Using a wide range of cognitive function and dementia endpoints, we failed to find genetic evidence of an adverse PCSK9-related impact, suggesting a neutral cognitive profile. In contrast, we observed adverse neurocognitive effects related to HMGCR inhibition, which may well be outweighed by the cardiovascular benefits of statin use, but nonetheless may warrant pharmacovigilance.
Subject(s)
Alzheimer Disease , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Acyl Coenzyme A , Alzheimer Disease/genetics , Cognition , Genome-Wide Association Study , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Mendelian Randomization Analysis , Proprotein Convertase 9/geneticsABSTRACT
Chronic heavy alcohol consumption is associated with increased mortality and morbidity and often leads to premature aging; however, the mechanisms of alcohol-associated cellular aging are not well understood. In this study, we used DNA methylation derived telomere length (DNAmTL) as a novel approach to investigate the role of alcohol use on the aging process. DNAmTL was estimated by 140 cytosine phosphate guanines (CpG) sites in 372 individuals with alcohol use disorder (AUD) and 243 healthy controls (HC) and assessed using various endophenotypes and clinical biomarkers. Validation in an independent sample of DNAmTL on alcohol consumption was performed (N = 4219). Exploratory genome-wide association studies (GWAS) on DNAmTL were also performed to identify genetic variants contributing to DNAmTL shortening. Top GWAS findings were analyzed using in-silico expression quantitative trait loci analyses and related to structural MRI hippocampus volumes of individuals with AUD. DNAmTL was 0.11-kilobases shorter per year in AUD compared to HC after adjustment for age, sex, race, and blood cell composition (p = 4.0 × 10-12). This association was partially attenuated but remained significant after additionally adjusting for BMI, and smoking status (0.06 kilobases shorter per year, p = 0.002). DNAmTL shortening was strongly associated with chronic heavy alcohol use (ps < 0.001), elevated gamma-glutamyl transferase (GGT), and aspartate aminotransferase (AST) (ps < 0.004). Comparison of DNAmTL with PCR-based methods of assessing TL revealed positive correlations (R = 0.3, p = 2.2 × 10-5), highlighting the accuracy of DNAmTL as a biomarker. The GWAS meta-analysis identified a single nucleotide polymorphism (SNP), rs4374022 and 18 imputed ones in Thymocyte Expressed, Positive Selection Associated 1(TESPA1), at the genome-wide level (p = 3.75 × 10-8). The allele C of rs4374022 was associated with DNAmTL shortening, lower hippocampus volume (p < 0.01), and decreased mRNA expression in hippocampus tissue (p = 0.04). Our study demonstrates DNAmTL-related aging acceleration in AUD and suggests a functional role for TESPA1 in regulating DNAmTL length, possibly via the immune system with subsequent biological effects on brain regions negatively affected by alcohol and implicated in aging.
Subject(s)
Adaptor Proteins, Signal Transducing , Aging , Alcoholism , Telomere Shortening , Humans , Alcohol Drinking/genetics , Alcoholism/genetics , DNA Methylation/genetics , Genome-Wide Association Study , Telomere/genetics , Adaptor Proteins, Signal Transducing/geneticsABSTRACT
OBJECTIVES: The efficacy of repetitive transcranial magnetic stimulation (rTMS) in clinically relevant neuroplasticity research depends on the degree to which stimulation induces robust, reliable effects. The high degree of interindividual and intraindividual variability observed in response to rTMS protocols, such as continuous theta burst stimulation (cTBS), therefore represents an obstacle to its utilization as treatment for neurological disorders. Brain-derived neurotrophic factor (BDNF) is a protein involved in human synaptic and neural plasticity, and a common polymorphism in the BDNF gene (Val66Met) may influence the capacity for neuroplastic changes that underlie the effects of cTBS and other rTMS protocols. While evidence from healthy individuals suggests that Val66Met polymorphism carriers may show diminished or facilitative effects of rTMS compared to their homozygous Val66Val counterparts, this has yet to be demonstrated in the patient populations where neuromodulatory therapies are most relevant. MATERIALS AND METHODS: We examined the effects of BDNF Val66Met polymorphism on cTBS aftereffects in stroke patients. We compared approximately 30 log-transformed motor-evoked potentials (LnMEPs) obtained per time point: at baseline and at 0, 10, 20, and 30 min after cTBS-600, from 18 patients with chronic stroke using single TMS pulses. We used linear mixed-effects regression with trial-level data nested by subject for higher statistical power. RESULTS: We found a significant interaction between BDNF genotype and pre-/post-cTBS LnMEPs. Val66Val carriers showed decrease in cortical excitability, whereas Val66Met carriers exhibited a modest increase in cortical excitability for 20 min poststimulation, followed by inhibition 30 min after cTBS-600. CONCLUSIONS: Our findings strongly suggest that BDNF genotype differentially affects neuroplastic responses to TMS in individuals with chronic stroke. This provides novel insight into potential sources of variability in cTBS response in patients, which has important implications for optimizing the utility of this neuromodulation approach. Incorporating BDNF polymorphism genetic screening to stratify patients prior to use of cTBS as a neuromodulatory technique in therapy or research may optimize response rates.