title: RhoV mediates apoptosis of RAW264.7 macrophages caused by osteoclast differentiation.
abstract: Macrophages, a type of immune cell, are the precursors of osteoclasts, and have important roles in bone remodeling and the immune system. In the present study, the RAW264.7 cell line was used as a macrophage model in order to study the macrophage changes during osteoclastogenesis. Receptor activator of nuclear factor κB ligand (RANKL) and macrophage colony‑stimulating factor (M‑CSF) induce the formation of osteoclasts from several precursor cells. Observation of RAW264.7 macrophage osteoclastogenesis under the induction of RANKL and M‑CSF revealed that except the few RAW264.7 macrophages that were differentiated into osteoclasts, almost all undifferentiated RAW264.7 macrophages underwent apoptosis. BRL‑3A cells have no differentiation ability, and RANKL and M‑CSF treatments did not induce BRL‑3A cell apoptosis. When osteoprotegerin (OPG) was used to completely inhibit the differentiation of RAW264.7 macrophages to osteoclasts, apoptosis did not occur amongst the RAW264.7 macrophages despite the action of RANKL and M‑CSF. Rac1, RhoA and RhoV are apoptosis‑associated genes in the Rho guanosine triphosphate (GTP)ase family. Their expression levels were detected using quantitative polymerase chain reaction (qPCR). During the process of osteoclast differentiation, the mRNA expression of RhoV was significantly upregulated, while apoptosis occurred in a large proportion of macrophages. However, when macrophage apoptosis was inhibited by OPG, RhoV expression was significantly downregulated. Conversely, Rac1 and RhoA expression did not vary in correspondence with the apoptotic rate of the RAW264.7 macrophages. In conclusion, differentiation of RAW264.7 macrophages into osteoclasts resulted in their apoptosis. OPG inhibited RAW264.7 macrophage differentiation into osteoclasts, and thereby inhibited the apoptosis of RAW264.7 macrophages. RhoV mediated the apoptosis of RAW264.7 macrophages during osteoclast differentiation.
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Ruilong
authors.initials: R
authors.lastname: Song
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Xuezhong
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Jiaqiao
authors.initials: J
authors.lastname: Zhu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Gao
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Qichao
authors.initials: Q
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Jiaming
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Laiyang
authors.initials: L
authors.lastname: Cheng
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Di
authors.initials: D
authors.lastname: Hu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Gu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, P.R. China.
authors.forename: Zongping
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010010:Osteoclasts / Q000166:cytology*; D053244:Osteoprotegerin / Q000494:pharmacology; D053245:RANK Ligand / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D016173:Macrophage Colony-Stimulating Factor; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein