Inactivating Variants in ANGPTL4 and Risk of Coronary Artery Disease

Abstract

Background: Higher-than-normal levels of circulating triglycerides are a risk factor for ischemic cardiovascular disease. Activation of lipoprotein lipase, an enzyme that is inhibited by angiopoietin-like 4 (ANGPTL4), has been shown to reduce levels of circulating triglycerides.

Methods: We sequenced the exons of ANGPTL4 in samples obtain from 42,930 participants of predominantly European ancestry in the DiscovEHR human genetics study. We performed tests of association between lipid levels and the missense E40K variant (which has been associated with reduced plasma triglyceride levels) and other inactivating mutations. We then tested for associations between coronary artery disease and the E40K variant and other inactivating mutations in 10,552 participants with coronary artery disease and 29,223 controls. We also tested the effect of a human monoclonal antibody against ANGPTL4 on lipid levels in mice and monkeys.

Results: We identified 1661 heterozygotes and 17 homozygotes for the E40K variant and 75 participants who had 13 other monoallelic inactivating mutations in ANGPTL4. The levels of triglycerides were 13% lower and the levels of high-density lipoprotein (HDL) cholesterol were 7% higher among carriers of the E40K variant than among noncarriers. Carriers of the E40K variant were also significantly less likely than noncarriers to have coronary artery disease (odds ratio, 0.81; 95% confidence interval, 0.70 to 0.92; P=0.002). K40 homozygotes had markedly lower levels of triglycerides and higher levels of HDL cholesterol than did heterozygotes. Carriers of other inactivating mutations also had lower triglyceride levels and higher HDL cholesterol levels and were less likely to have coronary artery disease than were noncarriers. Monoclonal antibody inhibition of Angptl4 in mice and monkeys reduced triglyceride levels.

Conclusions: Carriers of E40K and other inactivating mutations in ANGPTL4 had lower levels of triglycerides and a lower risk of coronary artery disease than did noncarriers. The inhibition of Angptl4 in mice and monkeys also resulted in corresponding reductions in these values. (Funded by Regeneron Pharmaceuticals.).

Figure 1. Fasting Metabolic Phenotypes in Carriers of Inactivating Mutations in ANGPTL4

Shown are genotype-specific measures for each trait among study participants with inactivating mutations in ANGPTL4, according to the presence of an inactivating allele in the single-peptide (SP), coiled-coil, and fibrinogen-like domains. The red line indicates the median value for all carriers of inactivating mutations. Each data point represents the value for a single carrier of the mutation specified above each box. The blue line indicates the median value for all participants who did not have an inactivating mutation in ANGPTL4 on sequencing. Overall, 13 of 10,552 participants with coronary artery disease and 58 of 29,223 controls carried an inactivating mutation. The body-mass index (BMI) is the weight in kilograms divided by the square of the height in meters. To convert the values for triglycerides to millimoles per liter, multiply by 0.01129. To convert values for cholesterol to millimoles per liter, multiply by 0.02586. To convert the values for glucose to millimoles per liter, multiply by 0.05551. CAD denotes coronary artery disease, HDL high-density lipoprotein, and LDL low-density lipoprotein.

Figure 2. Effect of REGN1001 on Serum Triglyceride Levels in Mice and Monkeys

Panel A shows serum triglyceride levels in fasting male mice (five in each group) that were homozygous for human ANGPTL4 and for ApoE deficiency before and after a single subcutaneous injection of monoclonal antibody (mAb) REGN1001 or control antibody at a dose of 10 mg per kilogram of body weight. Panel B shows plasma triglyceride levels in male cynomolgus monkeys (10 in each group) that received weekly intravenous injections of REGN1001 or control antibody at a dose of 5 mg per kilogram for 13 weeks. The triglyceride levels were evaluated before and 4, 8, and 14 weeks after study initiation. Panel C shows changes from baseline in plasma triglyceride levels in 4 of 5 obese rhesus monkeys with hyperlipidemia that received a single intravenous dose of 10 mg of REGN1001 per kilogram. One of the 5 monkeys with a very high triglyceride level at baseline had a dramatic reduction in plasma levels (Panel D). In Panels A, B, and C, values are means, and I bars indicate standard errors. A single asterisk indicates P<0.05, and double asterisks indicate P<0.001.