Intermittent parathyroid hormone (1-34) application regulates cAMP-response element binding protein activity to promote the proliferation and osteogenic differentiation of bone mesenchymal stromal cells, via the cAMP/PKA signaling pathway.
The potential effects of intermittent parathyroid hormone (1-34) [PTH (1-34)] administration on bone formation have previously been investigated. A number of studies have suggested that the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway is associated with PTH-induced osteogenic differentiation. However, the precise signaling pathways and molecular mechanism by which PTH (1-34) induces the osteogenic differentiation of bone mesenchymal stromal cells (BMSCs) remain elusive. The purpose of the present study was to investigate the mechanism underlying the effect of intermittent PTH (1-34) application on the proliferation and osteogenic differentiation of BMSCs. BMSCs were randomly divided into four groups, as follows: Osteogenic medium (control group); osteogenic medium and intermittent PTH (1-34); osteogenic medium and intermittent PTH (1-34) plus the adenylyl cyclase activator forskolin; and osteogenic medium and intermittent PTH (1-34) plus the PKA inhibitor H-89. A cell proliferation assay revealed that PTH (1-34) stimulates BMSC proliferation via the cAMP/PKA pathway. Furthermore, reverse transcription-quantitative polymerase chain reaction, alkaline phosphatase activity testing and cell examination using Alizarin Red S staining demonstrated that PTH (1-34) administration promotes osteogenic differentiation and mineralization, mediated by the cAMP/PKA pathway. Crucially, the results of western blot analyses suggested that PTH (1-34) treatment and, to a greater degree, PTH (1-34) plus forskolin treatment caused an increase in phosphorylated cAMP response element binding protein (p-CREB) expression, but the effect of PTH on p-CREB expression was blocked by H-89. In conclusion, the current study demonstrated that intermittent PTH (1-34) administration regulates downstream proteins, particularly p-CREB, in the cAMP/PKA signaling pathway, to enhance the proliferation, osteogenic differentiation and mineralization of BMSCs.
Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China.
Bailing
B
Chen
Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China.
Tao
T
Lin
Department of Spine Surgery, Chinese PLA General Hospital (301 Hospital), Beijing 100853, P.R. China.
Xiaoxi
X
Yang
Department of Orthopedics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510623, P.R. China.
Yiqiang
Y
Li
Department of Spine Surgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510630, P.R. China.
Denghui
D
Xie
Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China.
Haowen
H
Cui
bone mesenchymal stromal cells; cyclic adenosine monophosphate/protein kinase A pathway; osteogenic differentiation; parathyroid hormone (1-34)