title: Platelet‑derived growth factor promotes osteoblast proliferation by activating G‑protein‑coupled receptor kinase interactor‑1.
abstract: Platelet‑derived growth factor (PDGF) has been reported to stimulate bone fracture‑healing. Multiple studies have demonstrated that PDGF has a critical role in osteoblast or osteoprogenitor cell activation, although the underlying mechanism remains unclear. Studies have found that G‑protein‑coupled receptor kinase interactor‑1 (GIT1) is activated by PDGF and described as an important factor in bone metabolism. In the present study, the effects of PDGF and GIT1 on the proliferation and apoptosis of osteoblasts were investigated in cultured osteoblasts isolated from rat calvaria with PDGF stimulation and GIT1 small interfering RNA transfection. The results demonstrated that PDGF rapidly stimulated GTI1 expression in osteoblasts, increased osteoblast proliferation and inhibited cell apoptosis. Furthermore, cyclin D1 expression was significantly upregulated, the number of cells in the G0/G1 phase was decreased, while the number in the S phase was increased. In cells with knockdown of GIT1, the change stimulated by PDGF was not evident. The results indicate that, PDGF stimulated GIT1 activation of cyclin D1 expression, thereby promoting osteoblasts to enter the S phase from the stationary G0/G1 phase, leading to the proliferation of osteoblasts.
authors.affiliation: Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA, Guangzhou, Guangdong 510010, P.R. China.
authors.forename: You
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA, Guangzhou, Guangdong 510010, P.R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA, Guangzhou, Guangdong 510010, P.R. China.
authors.forename: Qingshui
authors.initials: Q
authors.lastname: Yin
authors.affiliation: Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA, Guangzhou, Guangdong 510010, P.R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xia
authors.affiliation: Department of Traumatic Orthopedics, General Hospital of Guangzhou Military Area Command of Chinese PLA, Guangzhou, Guangdong 510010, P.R. China.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015854:Up-Regulation
chemical_list: D018797:Cell Cycle Proteins; D020690:GTPase-Activating Proteins; C120766:Git1 protein, mouse; C485648:Git1 protein, rat; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D034741:RNA, Small Interfering; D019938:Cyclin D1