Decreased miR-181a expression in monocytes of obese patients is associated with the occurrence of metabolic syndrome and coronary artery disease.

Abstract

Inflammation during obesity is associated with higher risk of metabolic syndrome and coronary artery disease (CAD). Activation of the inflammatory toll-like receptor (TLR)/nuclear factor κB (NFκB) signaling in monocytes contributes to inflammation. Weight loss after bariatric surgery leads to significant improvement of obesity-related comorbidities. MicroRNA (miR), a class of small noncoding RNA, have been implicated as negative regulators of inflammatory processes. This study sought to identify dysregulated miR in monocytes of obese patients associated with TLR/NFκB signaling, metabolic syndrome, and CAD. This retrospective study included two independent cohorts of 21 morbidly obese and 125 high-risk obese and nonobese patients in a hospitalized care setting. INTERVENTION included bariatric surgery (n = 21) with a 3-month follow-up. miR expressions in CD14(+) monocytes were determined by microarray analysis. TLR/NFκB-related miR were identified by an in silico target prediction analysis. Their expression was validated by quantitative RT-PCR. Their association with metabolic syndrome and angiographically documented CAD was assessed. miR-181a, -181b, and -181d, identified as possible regulators of the TLR/NFκB signaling, were decreased in obese monocytes, and weight loss normalized their expression to levels observed in monocytes of lean persons. miR-181a but not miR-181b and miR-181d was associated with a higher number of metabolic syndrome components and with CAD even after adjustment for traditional risk factors, obesity and the metabolic syndrome. This study demonstrates that the TLR/NFκB-related miR-181a is down-regulated in monocytes of obese patients and suggests that it is a putative biomarker of metabolic syndrome and CAD.