Neuropeptide Y enhances proliferation and prevents apoptosis in rat bone marrow stromal cells in association with activation of the Wnt/β-catenin pathway in vitro

Neuropeptide Y (NPY) exhibits a critical but poorly understood regulatory signaling function and has been shown to promote proliferation, vascularization and migration in several types of cells and tissues. However, little is known about the specific role of NPY in the proliferation and apoptosis of bone marrow stromal cells (also known as bonemarrow-derivedmesenchymal stemcells, BMSCs), which contain a subpopulation ofmultipotent skeletal stem cells. Based on BrdU incorporation tests, Cell Counting Kit-8, flow cytometry, quantitative polymerase chain reaction and western blotting, we showed that NPY significantly promoted the proliferation of BMSCs in a concentration-dependent manner, with amaximal effect observed at a concentration of 10(-10) M for pro-proliferative and 10(-12) M for anti-apoptotic activities. Furthermore, NPY significantly increased the percentage of cells in S and G2/M phases. In addition, NPY exhibited a protective effect after 24 h of serum starvation as illustrated by a reduction in the apoptosis rate, degree of nuclear condensation, and expression of apoptosismarkers, including caspase-3, caspase-9 and Bax mRNA expression. NPY also increased the mRNA and protein expression levels of canonicalWnt signaling pathway proteins, including beta-catenin and c-myc, during the induced proliferative and anti-apoptotic processes. However, the proliferative and anti-apoptotic activities of NPY were partially blocked by both PD160170 (1 mu M) and DKK1 (0.2 mu g/mL). These compounds also blocked the mRNA and protein expression of beta-catenin, p-GSK-3 beta and c-myc. Therefore, the results of the present study demonstrated that NPY exerts a proliferative and protective effect on BMSCs in a dose-and time-dependentmanner in vitro, and importantly, these effects may be mediated via its Y1 receptor and involved in activation of the canonical Wnt signaling pathway. (C) 2017 The Authors. Published by Elsevier B.V.