Progranulin Promotes Osteogenic Differentiation and Osteosynthesis of Bone Marrow Mesenchymal Stem Cells and Alleviates Osteoporosis Through Phosphatidylinositol 3-Kinase/Protein Kinase B/Peroxisome Proliferator-Activated Receptor γ Pathway

Abstract

Bone marrow mesenchymal stem cells (BMSCs) have self-renewal potential with multi-directional differentiation. Progranulin prevents bone degradation, inhibits inflammation and protects bone tissue. However, the role of Progranulin in osteoporotic BMSCs is unclear. Osteoporosis (OP) rat models were prepared by ovarian removal and treated with different doses (5 and 10 μM) of Progranulin followed by analysis of BMP-2 level by ELISA, bone mineral density and ALP activity. OP rat BMSCs were isolated and assigned into control group and Progranulin group followed by analysis of Progranulin level by ELISA, cell proliferation by MTT assay, RUNX2 and COL1A1 mRNA level by Real time PCR, and PI3K/Akt/PPARγ signaling protein level by Western blot. Progranulin treatment of OP rats dose-dependently increased BMP-2 expression, bone density and ALP activity. Compared with OP group, there were significant differences (P <0.05). Progranulin expression and BMSCs proliferation was increased, and RUNX2 and COL1A1 mRNA expression was elevated in Progranulin-treated OP group along with increased PI3K/Akt expression and decreased PPARγ protein expression. Compared with OP group, the difference was statistically significant, and the change was more significant with increasing concentration (P <0.05). Progranulin promotes BMSCs osteogenic differentiation and proliferation by regulating PI3K/Akt/PPARγ signaling pathway, which is beneficial for OP rats’ bone synthesis.