Nesfatin-1 in human and murine cardiomyocytes: synthesis, secretion, and mobilization of GLUT-4

Abstract

Nesfatin-1, a satiety-inducing peptide identified in hypothalamic regions that regulate energy balance, is an integral regulator of energy homeostasis and a putative glucose-dependent insulin coadjuvant. We investigated its production by human cardiomyocytes and its effects on glucose uptake, in the main cardiac glucose transporter GLUT-4 and in intracellular signaling. Quantitative RT-PCR, Western blots, confocal immunofluorescence microscopy, and ELISA of human and murine cardiomyocytes and/or cardiac tissue showed that cardiomyocytes can synthesize and secrete nesfatin-1. Confocal microscopy of cultured cardiomyocytes after GLUT-4 labeling showed that nesfatin-1 mobilizes this glucose transporter to cell peripherals. The rate of 2-deoxy-D-[(3)H]glucose incorporation demonstrated that nesfatin-1 induces glucose uptake by HL-1 cells and cultured cardiomyocytes. Nesfatin-1 induced dose- and time-dependent increases in the phosphorylation of ERK1/2, AKT, and AS160. In murine and human cardiac tissue, nesfatin-1 levels varied with diet and coronary health. In conclusion, human and murine cardiomyocytes can synthesize and secrete nesfatin-1, which is able to induce glucose uptake and the mobilization of the glucose transporter GLUT-4 in these cells. Nesfatin-1 cardiac levels are regulated by diet and coronary health.