Extracellular miRNAs as mediators of obesity-associated disease.

Extracellular miRNAs are found in a variety of body fluids and mediate intercellular and interorgan communication thus regulating gene expression and cellular metabolism. These miRNAs are secreted either in small vesicles/exosomes (sEV) or bound to proteins such as Argonaute and HDL. Both exosomal and protein-bound circulating miRNAs are altered in obesity. Although all tissues can contribute to changes in circulating miRNAs, adipose tissue itself is an important source of these miRNAs, especially those in sEVs. These are derived from both adipocytes and macrophages and participate in crosstalk between these cells, as well as peripheral tissues, including liver, skeletal muscle, and pancreas, whose function may be impaired in obesity. Changes in levels of circulating miRNAs have also been linked to the beneficial effects induced by weight loss interventions, including diet, exercise, and bariatric surgery, further indicating a role for these miRNAs as mediators of disease pathogenesis. Here, we review the role of circulating miRNAs in the pathophysiology of obesity and explore their potential use as biomarkers and in therapy of obesity-associated metabolic syndrome. Abstract figure legend Extracellular miRNAs as indicators of metabolic status. Extracellular miRNAs are found in the circulation and are secreted bound to protein complex, lipoproteins particles or loaded into extracellular vesicles including microvesicles and exosomes. Many circulating microRNAs are dysregulated during obesity, but weight loss intervention such as exercise, diet and bariatric surgery can restore the miRNA secretion. Metabolic organs including adipose tissue, liver, skeletal muscle, and pancreas, whose function may be impaired during obesity, contribute to changes in the pool of obesity-associated circulating miRNAs. This article is protected by copyright. All rights reserved.