title: Effects of intermedin on proliferation, apoptosis and the expression of OPG/RANKL/M-CSF in the MC3T3-E1 osteoblast cell line.
abstract: Bone remodeling is a vital physiological process of healthy bone tissue in humans. It is characterized by the formation of bone by osteoblasts and its resorption by osteoclasts, and the bone resorbed by osteoclasts is replaced through the differentiation and activity of osteoblasts. Imbalances in this vital process lead to pathological conditions, including osteoporosis. Intermedin (IMD) as a newly discovered peptide in the calcitonin (CT) family of peptides, which shares similar functions with CT, calcitonin gene‑related peptide and amylin in bone resorption. However, the mechanism underlying its effect remains to be elucidated. This was investigated in the present study using the osteoblastic MC3T3‑E1 cell line, which was treated with different doses of IMD (0, 1, 10 and 100 nM). Cell proliferation, apoptosis and the expression of receptor activator of NF‑κB ligand (RANKL), osteoprotegerin (OPG) and macrophage colony‑stimulating factor (M‑CSF) were measured following treatment using multiple detection techniques, including an MTT assay, flow cytometry, reverse transcription‑quantitative polymerase chain reaction and western blot analysis. The resulting data demonstrated that IMD significantly inhibited the apoptosis of MC3T3‑E1 cells induced by serum‑free culture and dexamethasone, however, no significant effects on MC3T3‑E1 cell proliferation were observed. IMD had additional functions on the MC3T3‑E1 cells, including inhibition of the expression of RANKL and M‑CSF, and promotion of the expression of OPG. Previous studies have also demonstrated that RANKL and M‑CSF are two vital factor produced by osteoblasts to promote the maturation and differentiation of osteoclasts, and it has been reported that IMD can inhibit the osteoclast formation stimulated by RANKL and M‑CSF. Together with these findings, the present study concluded that IMD reduces bone resorption by inhibiting osteoblast apoptosis, decreasing the RANKL/OPG ratio and the expression of M-CSF, and inhibiting osteoclast maturation and differentiation.
authors.affiliation: Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Hongfei
authors.initials: H
authors.lastname: Ren
authors.affiliation: Department of Orthopedic Surgery, Gaizhou Central Hospital, Yingkou, Liaoning 115200, P.R. China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Ren
authors.affiliation: Department of Orthopedic Surgery, First Affiliated Hospital of Liaoning Medical University, Jingzhou, Liaoning 121001, P.R. China.
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Yu
authors.affiliation: Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Mu
authors.affiliation: Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Orthopedic Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Fu
mesh_terms: D000818:Animals; D017209:Apoptosis; D001862:Bone Resorption / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D015870:Gene Expression; D016173:Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009479:Neuropeptides / Q000502:physiology*; D010006:Osteoblasts / Q000502:physiology*; D053244:Osteoprotegerin / Q000378:metabolism*; D053245:RANK Ligand / Q000378:metabolism*
chemical_list: D009479:Neuropeptides; D053244:Osteoprotegerin; D053245:RANK Ligand; C506031:Tnfrsf11b protein, mouse; C505689:Tnfsf11 protein, mouse; C514552:intermedin protein, mouse; D016173:Macrophage Colony-Stimulating Factor