title: Endogenous bone morphogenetic protein 2 plays a role in vascular smooth muscle cell calcification induced by interleukin 6 in vitro.
abstract: Systemic inflammation is involved in vascular calcification and cardiovascular disease which is the leading cause of mortality in rheumatoid arthritis (RA). A high level of serum interleukin (IL)-6 plays a key role in local and systemic inflammation in RA. However, the underlying mechanisms remain unclear. We established a human umbilical artery smooth muscle cell (HUASMC) culturing method to investigate the possible role of IL-6 on vascular calcification. HUASMCs were obtained from umbilical arteries of healthy neonates. To detect calcification effects, HUASMCs were treated with (experimental group) or without (control group) recombinant human (rh) IL-6. The calcium deposition stain and calcium concentrations were measured, as well as the mRNA and protein levels of the regulating factor of osteogenic differentiation-bone morphogenetic protein (BMP) 2 and those calcifying related molecules including bone-specific alkaline phosphatase (BAP), osteoprotegerin (OPG), and osteopontin (OPN). Our study showed that rhIL-6 induced calcification of HUASMCs in a time- and dose-dependent manner, and upregulated expressions of BMP2, BAP, OPG, and OPN of HUASMCs. We then used the anti-BMP2 siRNA to knockdown the expression of endogenous BMP2 to confirm its role. HUASMCs were transfected with negative siRNA (control group) or the valid anti-BMP2 siRNA (experimental group) before they were treated with rhIL-6. Cells transfected with negative siRNA without IL-6 stimulating served as the blank group. The results showed that anti-BMP2 siRNA markedly decreased expressions of BMP2, BAP, OPG, and OPN, and also partly reduced the calcification of HUASMCs induced by rhIL-6. Collectively, according to our study, rhIL-6 could induce the extracellular calcification and osteogenic differentiation of human artery smooth muscle cells through upregulating endogenous BMP2 in vitro. This may be one of the underlying mechanisms of the overwhelming vascular calcification in RA.
authors.affiliation: 1 Department of Rheumatology and Clinical Immunology, the Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Mingshu
authors.initials: M
authors.lastname: Sun
authors.affiliation: 2 Department of Cardiac surgery, the Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.affiliation: 1 Department of Rheumatology and Clinical Immunology, the Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Xin
authors.affiliation: 1 Department of Rheumatology and Clinical Immunology, the Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: 1 Department of Rheumatology and Clinical Immunology, the Affiliated Hospital of Qingdao University, Qingdao, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.affiliation: 3 Department of Nephrology, Renji Hospital, Shanghai Jiaotong University Medical College, Shanghai, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Qian
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D015850:Interleukin-6; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins; D014469:Umbilical Arteries / Q000166:cytology; D061205:Vascular Calcification / Q000139:chemically induced / Q000378:metabolism*
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; C508600:IL6 protein, human; D015850:Interleukin-6; D053244:Osteoprotegerin; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C506895:SPP1 protein, human; C506030:TNFRSF11B protein, human; D053495:Osteopontin; D000469:Alkaline Phosphatase
keywords: RNA interfering; bone morphogenetic protein 2; interleukin 6; rheumatoid arthritis; vascular calcification