Background and aims: Liver expressed antimicrobial peptide 2 (LEAP2) is recently identified as a regulator in energy metabolism. This study aims to 1) investigate the role of leap2 in hepatic steatosis in C57BL/6 mice; 2) evaluate the association between circulating LEAP2 levels and liver fat contents in a hospital based case-control study.
Methods: The rodent experiment: western blotting and qPCR were performed to evaluate leap2 levels, lipid metabolism pathways and insulin signaling. shRNA was used to knockdown leap2. The clinical study: commercial ELISA kits were used to measure circulating LEAP2 levels (validated by western blotting). Liver fat content was estimated using MRI-derived proton density fat fraction and FibroScan-derived controlled attenuation parameter.
Results: The rodent experiment found the hepatic expression and secreted levels of leap2 were increased in mice with diet-induced steatosis. Leap2 knockdown ameliorated steatosis via lipolytic/lipogenic pathway and improved insulin sensitivity via IRS/AKT signaling. The clinical study reported increased circulating levels of LEAP2 in the subjects with steatosis. Moreover, LEAP2 correlated positively with age, body mass index, waist-to-hip ratio, liver fat content, fasting insulin and HOMA-IR, whereas inversely with acyl-ghrelin. Furthermore, the circulating levels of LEAP2 are dependent on liver fat content, acyl-ghrelin and fasting glucose. Lastly, circulating LEAP2 is an independent predictor of NAFLD.
Conclusions: The study suggests LEAP2 is associated with hepatic steatosis, which may involve lipolytic/lipogenic pathway and insulin signaling.
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