Plasma microRNA expression profiles associated with zinc exposure and type 2 diabetes mellitus: Exploring potential role of miR-144-3p in zinc-induced insulin resistance.

Zinc exposure has been linked with disordered glucose metabolism and type 2 diabetes mellitus (T2DM) development. However, the underlying mechanism remains unclear. We conducted population-based studies and in vitro experiments to explore potential role of microRNAs (miRNAs) in zinc-related hyperglycemia and T2DM. In the discovery stage, we identified plasma miRNAs expression profile for zinc exposure based on 87 community residents from the Wuhan-Zhuhai cohort through next-generation sequencing. MiRNAs profiling for T2DM was also performed among 9 pairs newly diagnosed T2DM-healthy controls. In the validating stage, plasma miRNA related to both of zinc exposure and T2DM among the discovery population was measured by qRT-PCR in 161 general individuals derived from the same cohort. Furthermore, zinc treated HepG2 cells with mimic or inhibitor were used to verify the regulating role of miR-144-3p. Based on the discovery and validating populations, we observed that miR-144-3p was positively associated with urinary zinc, hyperglycemia, and risk of T2DM. In vitro experiments confirmed that zinc-induced increase in miR-144-3p expression suppressed the target gene Nrf2 and downstream antioxidant enzymes, and aggravated insulin resistance. Our findings provided a novel clue for mechanism underlying zinc-induced glucose dysmetabolism and T2DM development, emphasizing the important role of miR-144-3p dysregulation.