Rare variant associations with waist-to-hip ratio in European-American and African-American women from the NHLBI-Exome Sequencing Project

Role of long noncoding RNAs in pathological cardiac remodeling after myocardial infarction: An emerging insight into molecular mechanisms and therapeutic potential

Myocardial infarction (MI) is the leading cause of heart failure (HF), accounting for high mortality and morbidity worldwide. As a consequence of ischemia/reperfusion injury during MI, multiple cellular processes such as oxidative stress-induced damage, cardiomyocyte death, and inflammatory responses occur. In the next stage, the proliferation and activation of cardiac fibroblasts results in myocardial fibrosis and HF progression. Therefore, developing a novel therapeutic strategy is urgently warranted to restrict the progression of pathological cardiac remodeling. Recently, targeting long non-coding RNAs (lncRNAs) provided a novel insight into treating several disorders. In this regard, numerous investigations have indicated that several lncRNAs could participate in the pathogenesis of MI-induced cardiac remodeling, suggesting their potential therapeutic applications. In this review, we summarized lncRNAs displayed in the pathophysiology of cardiac remodeling after MI, emphasizing molecular mechanisms. Also, we highlighted the possible translational role of lncRNAs as therapeutic targets for this condition and discussed the potential role of exosomes in delivering the lncRNAs involved in post-MI cardiac remodeling.

A non-coding variant linked to metabolic obesity with normal weight affects actin remodelling in subcutaneous adipocytes

Recent large-scale genomic association studies found evidence for a genetic link between increased risk of type 2 diabetes and decreased risk for adiposity-related traits, reminiscent of metabolically obese normal weight (MONW) association signatures. However, the target genes and cellular mechanisms driving such MONW associations remain to be identified. Here, we systematically identify the cellular programmes of one of the top-scoring MONW risk loci, the 2q24.3 risk locus, in subcutaneous adipocytes. We identify a causal genetic variant, rs6712203, an intronic single-nucleotide polymorphism in the COBLL1 gene, which changes the conserved transcription factor motif of POU domain, class 2, transcription factor 2, and leads to differential COBLL1 gene expression by altering the enhancer activity at the locus in subcutaneous adipocytes. We then establish the cellular programme under the genetic control of the 2q24.3 MONW risk locus and the effector gene COBLL1, which is characterized by impaired actin cytoskeleton remodelling in differentiating subcutaneous adipocytes and subsequent failure of these cells to accumulate lipids and develop into metabolically active and insulin-sensitive adipocytes. Finally, we show that perturbations of the effector gene Cobll1 in a mouse model result in organismal phenotypes matching the MONW association signature, including decreased subcutaneous body fat mass and body weight along with impaired glucose tolerance. Taken together, our results provide a mechanistic link between the genetic risk for insulin resistance and low adiposity, providing a potential therapeutic hypothesis and a framework for future identification of causal relationships between genome associations and cellular programmes in other disorders.

Rare loss of function variants in the hepatokine gene INHBE protect from abdominal obesity

Identifying genetic variants associated with lower waist-to-hip ratio can reveal new therapeutic targets for abdominal obesity. We use exome sequences from 362,679 individuals to identify genes associated with waist-to-hip ratio adjusted for BMI (WHRadjBMI), a surrogate for abdominal fat that is causally linked to type 2 diabetes and coronary heart disease. Predicted loss of function (pLOF) variants in INHBE associate with lower WHRadjBMI and this association replicates in data from AMP-T2D-GENES. INHBE encodes a secreted protein, the hepatokine activin E. In vitro characterization of the most common INHBE pLOF variant in our study, indicates an in-frame deletion resulting in a 90% reduction in secreted protein levels. We detect associations with lower WHRadjBMI for variants in ACVR1C, encoding an activin receptor, further highlighting the involvement of activins in regulating fat distribution. These findings highlight activin E as a potential therapeutic target for abdominal obesity, a phenotype linked to cardiometabolic disease.

Long non-coding RNA NORAD aggravates acute myocardial infarction by promoting fibrosis and apoptosis via miR-577/COBLL1 axis

Acute myocardial infarction (AMI) is one of the most common and serious cardiovascular diseases. With high morbidity and mortality, AMI has attracted the most attention. Emerging studies indicated that long noncoding RNAs (lncRNAs) play an important role in the progression of AMI. However, the role of NORAD in AMI remained unclear. The current study aimed to investigate the function and mechanism of NORAD in AMI. Bioinformatics tools and a wide range of assays including RT-qPCR, flow cytometry, TTC staining, western blot, luciferase reporter and caspase-3 activity assays were conducted to investigate the function and mechanism of NORAD in AMI. We found out that NORAD was significantly upregulated in AMI rats. Knockdown of NORAD alleviated H9c2 cell injury by reducing apoptosis and decreasing expression levels of fibrogenic factors. In addition, NORAD inhibition ameliorated AMI in a rat model by decreasing infarct size and fibrosis. We confirmed that NORAD bound to miR-577, which was downregulated in ischemia-reperfusion (I/R) rats and hypoxia-exposed H9c2 cells. Additionally, miR-577 combined with the 3'UTR of COBLL1, which was upregulated in I/R rats and hypoxia-exposed H9c2 cells. At last, rescue assay validated that the suppressive effects of NORAD knockdown on apoptosis and expression levels of fibrogenic factors were counteracted by COBLL1 overexpression. Overall, NORAD aggravates acute myocardial infarction by promoting fibrosis and apoptosis via the miR-577/COBLL1 axis. This novel discovery suggested that NORAD may serve as a potential therapeutic target for AMI patients.

Association of Genetic Variants Related to Gluteofemoral vs Abdominal Fat Distribution With Type 2 Diabetes, Coronary Disease, and Cardiovascular Risk Factors

IMPORTANCE

Body fat distribution, usually measured using waist-to-hip ratio (WHR), is an important contributor to cardiometabolic disease independent of body mass index (BMI). Whether mechanisms that increase WHR via lower gluteofemoral (hip) or via higher abdominal (waist) fat distribution affect cardiometabolic risk is unknown.

OBJECTIVE

To identify genetic variants associated with higher WHR specifically via lower gluteofemoral or higher abdominal fat distribution and estimate their association with cardiometabolic risk.

DESIGN, SETTING, AND PARTICIPANTS

Genome-wide association studies (GWAS) for WHR combined data from the UK Biobank cohort and summary statistics from previous GWAS (data collection: 2006-2018). Specific polygenic scores for higher WHR via lower gluteofemoral or via higher abdominal fat distribution were derived using WHR-associated genetic variants showing specific association with hip or waist circumference. Associations of polygenic scores with outcomes were estimated in 3 population-based cohorts, a case-cohort study, and summary statistics from 6 GWAS (data collection: 1991-2018).

EXPOSURES

More than 2.4 million common genetic variants (GWAS); polygenic scores for higher WHR (follow-up analyses).

MAIN OUTCOMES AND MEASURES

BMI-adjusted WHR and unadjusted WHR (GWAS); compartmental fat mass measured by dual-energy x-ray absorptiometry, systolic and diastolic blood pressure, low-density lipoprotein cholesterol, triglycerides, fasting glucose, fasting insulin, type 2 diabetes, and coronary disease risk (follow-up analyses).

RESULTS

Among 452 302 UK Biobank participants of European ancestry, the mean (SD) age was 57 (8) years and the mean (SD) WHR was 0.87 (0.09). In genome-wide analyses, 202 independent genetic variants were associated with higher BMI-adjusted WHR (n = 660 648) and unadjusted WHR (n = 663 598). In dual-energy x-ray absorptiometry analyses (n = 18 330), the hip- and waist-specific polygenic scores for higher WHR were specifically associated with lower gluteofemoral and higher abdominal fat, respectively. In follow-up analyses (n = 636 607), both polygenic scores were associated with higher blood pressure and triglyceride levels and higher risk of diabetes (waist-specific score: odds ratio [OR], 1.57 [95% CI, 1.34-1.83], absolute risk increase per 1000 participant-years [ARI], 4.4 [95% CI, 2.7-6.5], P < .001; hip-specific score: OR, 2.54 [95% CI, 2.17-2.96], ARI, 12.0 [95% CI, 9.1-15.3], P < .001) and coronary disease (waist-specific score: OR, 1.60 [95% CI, 1.39-1.84], ARI, 2.3 [95% CI, 1.5-3.3], P < .001; hip-specific score: OR, 1.76 [95% CI, 1.53-2.02], ARI, 3.0 [95% CI, 2.1-4.0], P < .001), per 1-SD increase in BMI-adjusted WHR.

CONCLUSIONS AND RELEVANCE

Distinct genetic mechanisms may be linked to gluteofemoral and abdominal fat distribution that are the basis for the calculation of the WHR. These findings may improve risk assessment and treatment of diabetes and coronary disease.