Age-related diseases like chronic obstructive pulmonary disease (COPD) occur at higher rates in people living with human immunodeficiency virus (PLWH) than in uninfected populations.
To identify ...whether accelerated aging can be observed in the airways of PLWH with COPD, manifest by a unique DNA methylation signature.
Bronchial epithelial brushings from PLWH with and without COPD and HIV-uninfected adults with and without COPD (
= 76) were profiled for DNA methylation and gene expression. We evaluated global Alu and LINE-1 methylation and calculated the epigenetic age using the Horvath clock and the methylation telomere length estimator. To identify genome-wide differential DNA methylation and gene expression associated with HIV and COPD, robust linear models were used followed by an expression quantitative trait methylation (eQTM) analysis.
Epigenetic age acceleration and shorter methylation estimates of telomere length were found in PLWH with COPD compared with PLWH without COPD and uninfected patients with and without COPD. Global hypomethylation was identified in PLWH. We identified 7,970 cytosine bases located next to a guanine base (CpG sites), 293 genes, and 9 expression quantitative trait methylation-gene pairs associated with the interaction between HIV and COPD. Actin binding LIM protein family member 3 (
) was one of the novel candidate genes for HIV-associated COPD highlighted by our analysis.
Methylation age acceleration is observed in the airway epithelium of PLWH with COPD, a process that may be responsible for the heightened risk of COPD in this population. Their distinct methylation profile, differing from that observed in patients with COPD alone, suggests a unique pathogenesis to HIV-associated COPD. The associations warrant further investigation to establish causality.
SARS-CoV-2 is responsible for the coronavirus disease 2019 (COVID-19) and the current health crisis. Despite intensive research efforts, the genes and pathways that contribute to COVID-19 remain ...poorly understood. We, therefore, used an integrative genomics (IG) approach to identify candidate genes responsible for COVID-19 and its severity
.
We used Bayesian colocalization (COLOC) and summary-based Mendelian randomization to combine gene expression quantitative trait loci (eQTLs) from the Lung eQTL (
n
= 1,038) and eQTLGen (
n
= 31,784) studies with published COVID-19 genome-wide association study (GWAS) data from the COVID-19 Host Genetics Initiative. Additionally, we used COLOC to integrate plasma protein quantitative trait loci (pQTL) from the INTERVAL study (
n
= 3,301) with COVID-19 loci. Finally, we determined any causal associations between plasma proteins and COVID-19 using multi-variable two-sample Mendelian randomization (MR). The expression of 18 genes in lung and/or blood co-localized with COVID-19 loci. Of these, 12 genes were in suggestive loci (
P
GWAS
< 5 × 10
–05
).
LZTFL1, SLC6A20, ABO, IL10RB and IFNAR2
and
OAS1
had been previously associated with a heightened risk of COVID-19 (
P
GWAS
< 5 × 10
–08
). We identified a causal association between
OAS1
and COVID-19 GWAS. Plasma ABO protein, which is associated with blood type in humans, demonstrated a significant causal relationship with COVID-19 in the MR analysis; increased plasma levels were associated with an increased risk of COVID-19 and, in particular, severe COVID-19. In summary, our study identified genes associated with COVID-19 that may be prioritized for future investigations. Importantly, this is the first study to demonstrate a causal association between plasma ABO protein and COVID-19.
Cell entry of SARS-CoV-2, the novel coronavirus causing COVID-19, is facilitated by host cell angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). We aimed to ...identify and characterize genes that are co-expressed with ACE2 and TMPRSS2, and to further explore their biological functions and potential as druggable targets. Using the gene expression profiles of 1,038 lung tissue samples, we performed a weighted gene correlation network analysis (WGCNA) to identify modules of co-expressed genes. We explored the biology of co-expressed genes using bioinformatics databases, and identified known drug-gene interactions. ACE2 was in a module of 681 co-expressed genes; 10 genes with moderate-high correlation with ACE2 (r > 0.3, FDR < 0.05) had known interactions with existing drug compounds. TMPRSS2 was in a module of 1,086 co-expressed genes; 31 of these genes were enriched in the gene ontology biologic process 'receptor-mediated endocytosis', and 52 TMPRSS2-correlated genes had known interactions with drug compounds. Dozens of genes are co-expressed with ACE2 and TMPRSS2, many of which have plausible links to COVID-19 pathophysiology. Many of the co-expressed genes are potentially targetable with existing drugs, which may accelerate the development of COVID-19 therapeutics.
The LG/J x SM/J advanced intercross line of mice (LG x SM AIL) is a multigenerational outbred population. High minor allele frequencies, a simple genetic background, and the fully sequenced LG and SM ...genomes make it a powerful population for genome-wide association studies. Here we use 1,063 AIL mice to identify 126 significant associations for 50 traits relevant to human health and disease. We also identify thousands of cis- and trans-eQTLs in the hippocampus, striatum, and prefrontal cortex of ~200 mice. We replicate an association between locomotor activity and Csmd1, which we identified in an earlier generation of this AIL, and show that Csmd1 mutant mice recapitulate the locomotor phenotype. Our results demonstrate the utility of the LG x SM AIL as a mapping population, identify numerous novel associations, and shed light on the genetic architecture of mammalian behavior.
Muscle bulk in adult healthy humans is highly variable even after height, age, and sex are accounted for. Low muscle mass, due to fewer and/or smaller constituent muscle fibers, would exacerbate the ...impact of muscle loss occurring in aging or disease. Genetic variability substantially influences muscle mass differences, but causative genes remain largely unknown. In a genome-wide association study (GWAS) on appendicular lean mass (ALM) in a population of 85,750 middle-aged (aged 38–49 years) individuals from the UK Biobank (UKB), we found 182 loci associated with ALM (p < 5 × 10−8). We replicated associations for 78% of these loci (p < 5 × 10−8) with ALM in a population of 181,862 elderly (aged 60–74 years) individuals from UKB. We also conducted a GWAS on hindlimb skeletal muscle mass of 1,867 mice from an advanced intercross between two inbred strains (LG/J and SM/J); this GWAS identified 23 quantitative trait loci. Thirty-eight positional candidates distributed across five loci overlapped between the two species. In vitro studies of positional candidates confirmed CPNE1 and STC2 as modifiers of myogenesis. Collectively, these findings shed light on the genetics of muscle mass variability in humans and identify targets for the development of interventions for treatment of muscle loss. The overlapping results between humans and the mouse model GWAS point to shared genetic mechanisms across species.
Chronic obstructive pulmonary disease (COPD) is an age-related condition that has been associated with early telomere attrition; the clinical implications of telomere shortening in COPD are not well ...known. In this study we aimed to determine the relationship of the epigenetic regulation of telomeric length in peripheral blood with the risk of exacerbations and hospitalization in patients with COPD.
Blood DNA methylation profiles were obtained from 292 patients with COPD enrolled in the placebo arm of the Macrolide Azithromycin to Prevent Rapid Worsening of Symptoms Associated with Chronic Obstructive Pulmonary Disease (MACRO) Study and who were followed for 1-year. We calculated telomere length based on DNA methylation markers (DNAmTL) and related this biomarker to the risk of exacerbation and hospitalization and health status (St. George Respiratory Questionnaire SGRQ) score over time using a Cox proportional hazards model. We also used linear models to investigate the associations of DNAmTL with the rates of exacerbation and hospitalization (adjusted for chronological age, lung function, race, sex, smoking, body mass index and cell composition).
Participants with short DNAmTL demonstrated increased risk of exacerbation (P = 0.02) and hospitalization (P = 0.03) compared to those with longer DNAmTL. DNAmTL age acceleration was associated with higher rates of exacerbation (P = 1.35 × 10
) and hospitalization (P = 5.21 × 10
) and poor health status (lower SGRQ scores) independent of chronological age (P = 0.03).
Telomeric age based on blood DNA methylation is associated with COPD exacerbation and hospitalization and thus a promising biomarker for poor outcomes in COPD.
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