Evaluation of GDF15 as a therapeutic target of cardiometabolic diseases in human: A Mendelian randomization studyResearch in context

Background: Growth differentiation factor 15 (GDF15) is a key regulator of body weight in animals by regulating food intake. Its receptor, glial cell-derived neurotrophic factor receptor alpha-like (GFRAL), was identified recently. Pre-clinical studies showed that it is a promising therapeutic target for cardiometabolic diseases and anorexia/cachexia. Although many pharmaceutical companies are developing drugs targeting GFRAL, whether the findings from animal studies can be extrapolated to man is unknown. Mendelian randomization (MR) is useful in investigating the relationship between risk factors and disease outcomes. We aimed to use a two-sample MR approach to evaluate the clinical usefulness of targeting GDF15 for cardiometabolic diseases. Methods: Genetic instruments and summary statistics for MR analyses were obtained from a large genome-wide association study (GWAS) of GDF15 and cardiometabolic outcomes (n = 27,394 to 644,875), including body mass index, waist-hip ratio, waist circumference, whole-body lean mass, fat percentage, Type 2 Diabetes, fasting glucose, glycated haemoglobin, fasting insulin, LDL-cholesterol, HDL-cholesterol, total cholesterol, triglycerides, coronary artery disease, and estimated BMD (eBMD). Conventional inverse variance weighted (IVW) method was adopted to obtain the causal estimates of GDF-15 with different outcomes; weighted median and MR-egger were used for sensitivity analyses. Findings: There was null association between GDF15 levels and anthropometric outcomes. One SD increase in genetically-determined GDF15 was significantly associated with reduced HDL-C (beta: -0.048SD; SE: 0.014; P = .001) but the result was not significant in sensitivity analyses. A consistent significant causal association was observed between GDF15 and eBMD in IVW (beta: 0.026 SD; SE: 0.005; P < .001) and subsequent sensitivity analyses. Interpretation: This study sheds lights on the potential of drugs targeting the GDF15/GFRAL axis. It suggested that the effect of targeting GDF15/GFRAL axis for weight control in human may be different from the effects observed in animal studies. GDF15 treatment may improve BMD in humans. Fund: No specific funding was received for this study

Exome-wide association analysis reveals novel coding sequence variants associated with lipid traits in Chinese

Blood lipids are important risk factors for coronary artery disease (CAD). Here we perform an exome-wide association study by genotyping 12,685 Chinese, using a custom Illumina HumanExome BeadChip, to identify additional loci influencing lipid levels. Single-variant association analysis on 65,671 single nucleotide polymorphisms reveals 19 loci associated with lipids at exome-wide significance (P<2.69 × 10−7), including three Asian-specific coding variants in known genes (CETP p.Asp459Gly, PCSK9 p.Arg93Cys and LDLR p.Arg257Trp). Furthermore, missense variants at two novel loci—PNPLA3 p.Ile148Met and PKD1L3 p.Thr429Ser—also influence levels of triglycerides and low-density lipoprotein cholesterol, respectively. Another novel gene, TEAD2, is found to be associated with high-density lipoprotein cholesterol through gene-based association analysis. Most of these newly identified coding variants show suggestive association (P<0.05) with CAD. These findings demonstrate that exome-wide genotyping on samples of non-European ancestry can identify additional population-specific possible causal variants, shedding light on novel lipid biology and CAD