Circulating microRNA responses between 'high' and 'low' responders to a 16-wk diet and exercise weight loss intervention

Background: Interactions between diet, physical activity and genetic predisposition contribute to variable body mass changes observed in response to weight loss interventions. Circulating microRNAs (c-miRNAs) may act as ‘biomarkers’ that are associated with the rate of change in weight loss, and/or play a role in regulating the biological variation, in response to energy restriction. Objective: To quantify targeted c-miRNAs with putative roles in energy metabolism and exercise adaptations following a 16 wk diet and exercise intervention in individuals with large (high responders; HiRes) versus small (low responders; LoRes) losses in body mass. Methods: From 89 male and female overweight/obese participants who completed the intervention (energy restriction from diet, 250 kcal/d, and exercise, 250 kcal/d), subgroups of HiRes ( > 10% body mass loss, n = 22) and LoRes ( < 5% body mass loss, n = 18) were identified. From resting plasma samples collected after an overnight fast pre and post intervention, RNA was extracted, quantified and reverse transcribed. Thirteen c-miRNA selected a priori were analysed using a customised 96-well miScript miRNA PCR Array. Results: Loss of body mass (-11.0 ± 2.3 kg vs. -3.0 ± 1.3 kg; P < 0.01) and fat mass (-11.1 ± 2.6 kg vs. -3.9 ± 1.6 kg; P < 0.01) was greater for HiRes than LoRes (P < 0.001). Expression of c-miR-935 was higher in LoRes compared to HiRes pre- (~47%; P = 0.025) and post- (~100%; P < 0.01) intervention and was the only c-miRNA differentially expressed at baseline between groups. The abundance of c-miR-221-3p and -223-3p increased pre- to post-intervention in both groups (~57–69% and ~25–90%, P < 0.05). There was a post-intervention increase in c-miR-140 only in LoRes compared to HiRes (~23%, P = 0.016). Conclusion: The differential expression and responses of selected c-miRNAs in overweight/obese individuals to an exercise and diet intervention suggests a putative role for these ‘biomarkers’ in the prediction or detection of individual variability to weight loss interventions.