Different functions of the two isoforms of osteopontin (iOPN and sOPN) in the proliferation and differentiation of osteoblast and osteoclast: iOPN inhibits osteoclasts' proliferation while sOPN stimulates osteoblasts' differentiation and osteoclasts' resorption

作者：Zhang, Jie; Xu, Liyu; Shen, Yong; Wang, Xiaolan; Xu, Guochao^*

来源：International Journal of Clinical and Experimental Medicine, 2017, 10(1): 224-241.

• Osteopontin isoforms
• osteoclast
• osteoblast
• proliferation and differentiation
• osteoclast resorption

Osteopontin (OPN) plays an important role in maintaining bone homeostasis. However, functions of its two isoforms (iOPN and sOPN) in bone are poorly understood. This paper aimed to identify which isoform of OPN could be beneficial to bone regeneration. The CCK-8 assays showed that cell proliferation was significantly inhibited in iOPN-over expressed RAW264.7 cells (Adv-iOPN) compared to wild RAW264.7 cells (Adv-Control) via increasing cells at GO phase. Osteogenic differentiation was dramatically enhanced after treatment with sOPN through AKT and p38 pathway. ALP activity, collagen expression, calcium mineralization and the expression of osteogenic-related gene Runx2 was significantly increased by sOPN. In addition, osteoclastogenesis was dramatically enhanced after treatment with sOPN through AKT and NF-KB pathway. TRAP positive cell count, bone resorption pit formation and expression of osteoclastic marker genes (TRAP, RANK and Cathpesin-K) were significantly increased in RAW264.7 cells. The present results also indicated that iOPN has an inhibitory role in bone loss by preventing osteoclast proliferation, while sOPN plays positive roles in bone formation of osteoblasts and osteoclast resorption.

• 出版日期2017
• 单位浙江医院; 浙江大学