1278-P: The Tale of Caveolin 1 rs1997623 Variant in Obesity and Metabolic Syndrome

We Have previously established that caveolin-1 (CAV1) rs1997623 C/A variant is associated with metabolic syndrome in obese children (PMID: 30622557) and adults (ADA 82) . Here, we evaluated the functional role of the identified variant in association with obesity. Sequence analysis revealed that the variant is located at CAV1 regulatory region and creates a site for EBF Transcription Factor 1 (EBF1) . DNA fragment (240pb) flanking the variant was cloned upstream luciferase reporter gene. Wildtype, CAV1-C-Luc, and the generated mutant, CAV1-A-Luc, were individually transfected into pre-adipocytes. CAV1-A-luc significantly upregulated Luciferase activity indicating a prospective functional role of CAV1-A allele in CAV1 regulation. The reporter gene activity was differential regulated in lean versus obese pre-adipocytes. Co-transfections with EBF1 construct resulted in a significant upregulation in CAV1-A Luc activity, particularly in pre-adipocytes from obese individuals. The role of EBF1 was further evaluated in vivo using ChIP assays. PCR analysis using specific primers flanking the CAV1 variant and anti-bodies against EBF1 showed a significant elevated enrichment of chromatins from obese individuals, which was also associated with an enrichment for H3K27ac at the same locus, indicating active transcription. Moreover, CAV1 expression was differentially regulated in response to EBF1 siRNA/overexpression in pre-adipocytes harboring CAV1 A/A or A/C alleles relative to that with C/C allele. Furthermore, a significant reduction of DNA methylation at the variant locus was observed particularly in preadipocytes with A/A alleles. Finally, RNA isolated from adipose tissue of lean and obese individuals showed a significant correlation between CAV1 and cytokines transcripts in healthy obese individuals, at least in part, is due to CAV1 rs1997623 variant as verified by sequence analysis. Taken together, our study delineates the role of CAV1 rs1997623 variant in the context of obesity and MetS. Disclosure A.Al madhoun: None. D.Haddad: None. S.P.Kochumon: None. R.Nizam: None. S.Jacob: None. S.T.Sindhu: None. R.Ahmad: None. F.Almulla: None. Funding Kuwait Foundation for the Advancement of Sciences (KFAS) and Dasman Diabetes Institute, Project RA CB-2021-007