Metabolome-wide association of carotid intima media thickness identifies FDX1 as a determinant of cholesterol metabolism and cardiovascular risk in Asian populations.

The burden of cardiovascular disease (CVD) is rising in the Asia-Pacific region, in contrast to falling CVD mortality rates in Europe and North America. To provide new insights into the pathways influencing cardiovascular risk in Asian populations, we quantified 883 metabolites by untargeted mass spectroscopy in 8,124 Singaporean adults, and investigated their relationships to carotid intima media thickness (cIMT), a marker of atherosclerosis. We found that plasma concentrations of 3beta-hydroxy-5-cholestenoate (3BH5C), a cholesterol metabolite, associated inversely with cIMT (Beta[SE]=-0.013[0.002]). Genetic instruments support a causal relationship of 3BH5C metabolic pathways on cardiovascular risk, with a 5-6 fold higher effect size in Asians (ORGSMR[95% CI]=0.89[0.87-0.92], ORIVW[95% CI]=0.86[0.80-0.92]) compared to Europeans (ORIVW[95% CI] = 0.98[0.96-0.99]). Colocalization analyses indicate the presence of a shared causal variant between 3BH5C plasma levels and expression of ferredoxin-1 (FDX1), a protein essential for sterol and bile acid synthesis. We validated FDX1 as a key regulator of 3BH5C synthesis in hepatocytes, and macrophages, and cholesterol efflux in aortic smooth muscle cells, through knockout and overexpression models. In summary, this study makes an important contribution to our understanding of the metabolic basis for atherosclerosis in Asian populations, and identifies FDX1 as a potential therapeutic target for prevention of CVD. ### Competing Interest Statement K.E.W, P.A.S, R.S and G.A.M are employees of Metabolon, and may hold stock/stock options in Metabolon. The rest of the authors have no conflicting interests. ### Funding Statement This work was supported by intramural funding from Nanyang Technological University, Lee Kong Chian School of Medicine, and the National Healthcare Group. J.C.C is supported by: the Singapore Ministry of Health and National Medical Research Council STaR funding scheme [NMRC/StaR/0028/2017], LCG funding [MOH-000271], Phase II National Precision Medicine Programme (Research Platform and Data Enablers) [NMRC/PRECISE/2020], the Singapore Agency for Science Technology and Research IAF-PP National Precision Medicine Program Phase 1A (A Population Level Genomic Infrastructure) [H17/01/a0/007], and the IAF-PP Asian Skin Microbiome Programme [H18/01/a0/016]. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/Institutional Review Board of the Nanyang Technological University granted ethical approval for this work (IRB-2016-11-030) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data access request can be submitted to the HELIOS Data Access Committee by emailing helios_science@ntu.edu.sg for details.