Revisiting the role of GDF15 in atherosclerosis in mouse and human

Growth differentiation factor 15 (GDF15) is a key regulator of food intake and energy metabolism. GDF15 mimetic drugs for the treatment of metabolic syndrome and obesity are under clinical development. While GDF15 presents a promising target for weight management, its potential cardiovascular actions remain elusive. In this study we investigated the role of GDF15 in macrophage function and atherosclerosis pathogenesis and whether GDF15 acts both as a biomarker and mediator of atherosclerosis severity. ApoE^-/- mice were fed a high-cholesterol diet (HCD, 1.25% cholesterol) for 6, 12 or 18 weeks to establish atherosclerotic models. We showed that serum levels of GDF15 were elevated in ApoE^-/- mice with atheroprogression; increased serum levels of GDF15 were also observed in patients with coronary artery disease. Enlightened by this finding, we established atherosclerotic model in Gdf15^-/- mice by injecting with AAV8-PCSK9^D377Y virus and feeding HCD for 12 or 16 weeks. We showed that global Gdf15 knockout, whether in male or female mice, did not alter plaque size in en face aorta, lesion in aortic sinus, size of necrotic core or plaque composition. In macrophage-derived foam cells isolated from atherosclerotic mice, neither Gdf15 deletion nor the treatment with recombinant GDF15 protein (1, 10, 100 ng/mL) affected lipid deposition or macrophage polarization. To translate this finding into a clinically relevant scenario, we performed Mendelian randomization (MR) analysis, and found no significant causal association between circulating GDF15 levels and the incidence of cardiovascular diseases. Furthermore, MR studies suggest that genetic associations between GDF15 and factors such as BMI, ApoB, LDL and HDL were not significant in plasma data from the UK Biobank and the deCODE cohort. In summary, this study demonstrates that global Gdf15 deficiency does not affect the development of atherosclerosis in male or female mice despite the positive association between circulating GDF15 levels and disease progression in mice and human. Thus, GDF15 in circulation is a potential biomarker, but not a causal mediator, of atherosclerosis. Long-term cardiovascular safety of GDF15-targeted therapies warrants further investigation.