Neuromedin S regulates steroidogenesis and proliferation in goat Leydig cells through modulating mitochondrial function

Neuromedin S (NMS) is a neuroregulatory substance and has many important roles in regulating physiological functions in animal cells, while their specific functions and mechanisms in Leydig cells (LCs) of the testis remain unclear. The current study aims to investigate the role and potential mechanisms of NMS and its receptors in regulating steroidogenesis and proliferation in goat LCs. We found that NMS and its receptors were mainly expressed in LCs of goat testes at different ages (1-day-old, 3-month-old, and 9-month-old), and the highest expressions detected at age three months. NMS addition significantly enhanced the testosterone secretion, STAR, CYP11A1, 3BHSD, and CYP17A1 expressions, cell proliferation, and PCNA expression in vitro cultured goat LCs. Mechanistically, NMS addition increased G1/S cell population, the expressions of CCND1, CDK4 and CDK6, the activities of SOD2 and CAT, and enhanced the mitochondrial fusion, the production of ATP, and mitochondrial membrane potential, while inhibited cellular ROS production, and maintained a low ubiquitination level of mitochondrial proteins. Notably, these effects of NMS addition on goat LCs were suppressed by co-treatment with NMUR2 knockdown. Therefore, these data suggest that activating NMUR2 with NMS enhances testosterone production and cell proliferation in goat LCs through modulating mitochondrial morphology, function, and autophagy. These findings may provide a novel view of the regulatory mechanisms involved in male sexual maturation.