Efeitos in vitro da Kisspeptina (KP-10) na diferenciação e expressão de marcadores osteogênicos de células tronco mesenquimais da medula óssea de ratas adultas

Abstract

Kisspeptin is a neuropeptide that binds to the GPR54 receptor, exerting several functions mainly in the nervous and reproductive systems of the body. However, its effects and mechanisms of action on the skeletal system remain poorly understood. This study evaluated the effect of different concentrations of kisspeptin (Kp-10) in vitro on the osteogenic differentiation of mesenchymal stem cells (MSCs) extracted from the bone marrow (BM) of adult Wistar rats. Two-month-old female rats were euthanized to extract BM from long bones to obtain MSCs. In vitro, 4 experimental groups were established: control, and Kp-10 at concentrations of 0.01 µg/mL, 0.05 µg/mL and 0.1 µg/mL. After induction of osteogenic differentiation, cell viability was evaluated by the MTT test, alkaline phosphatase activity, collagen synthesis, percentage of area covered by MSCs/field, mineralized nodules/field, immunocytochemistry for the GPR54 receptor, and evaluation of gene expression of type I collagen, osteocalcin, osteopontin, bone sialoprotein, RUNX-2, and BMP-2 were done by real-time RT-PCR. It was observed that MSCs have a GPR54 receptor to which Kp-10 binds during osteogenic differentiation, promoting a direct negative effect on osteogenic differentiation. This effect was observed at all concentrations used (0.01, 0.05, and 0.1 µg/mL) and in a concentration-dependent manner, characterized by a decrease in the activity of alkaline phosphatase, collagen synthesis, mineralized nodules and by the decreased expression of gene transcripts for type I collagen, osteocalcin, osteopontin, and RUNX-2. We conclude that Kp-10 in vitro inhibits the osteogenic differentiation of MSCs extracted from the BM of adult Wistar rats.