Objective: Exosomal micro RNAs (miRNAs) are valuable biomarkers and regulate biological processes in obesity. Bariatric surgery has a beneficial effect on obese patients, however the mechanisms behind this benefit are not clear. We attempted to identify exosomal miRNA signatures associated with obesity and examined exosomal miRNA changes after bariatric surgery.
Methods: Healthy volunteers (HV, n = 18) and non-diabetic obese patients (n = 16) were enrolled prospectively. We assessed the serum exosome miRNA profiles of HVs and obese patients using RNA sequencing (RNA-seq) cross-sectionally. To evaluate the effect of bariatric surgery, we conducted exosomal miRNA analysis 6 months after surgery in 12 obese patients.
Results: RNA-seq analysis showed 224 obesity-related microRNAs. Using 2log fold changes as cut-offs, we identified that the expression of 72 (up-regulation = 57, down-regulation = 15) exosomal miRNAs in obese patients compared to HV and 41 (up-regulation = 9, down-regulation = 32) exosomal miRNAs in pre-surgery compared to post-surgery. Biological pathway analysis of predicted gene targets of surgery-responsive miRNAs corresponding obesity related miRNAs included insulin receptor signaling (IRS) cascade, IRS-mediated signaling, IRS- mediated events and PI3K cascade.
Conclusion: Obese patients have different serum exosome miRNAs expression profiles compared to healthy volunteers. Weight loss after bariatric also induces changes in exosomal miRNAs profiles. OP4-