title: P-glycoprotein overexpression in bone marrow-derived multipotent stromal cells decreases the risk of steroid-induced osteonecrosis in the femoral head.
abstract: P-glycoprotein (P-gp) plays a role in steroid-induced osteonecrosis of the femoral head (ONFH), but the underlying mechanism remains unknown. We hypothesized that P-gp overexpression can prevent ONFH by regulating bone marrow-derived multipotent stromal cell (BMSC) adipogenesis and osteogenesis. BMSCs from Sprague-Dawley rats were transfected with green fluorescent protein (GFP) or the multidrug resistance gene 1 (MDR1) encoding GFP and P-gp. Dexamethasone was used to induce BMSC differentiation. Adipogenesis was determined by measuring peroxisome proliferator-activated receptor (PPAR-γ) expression and the triglyceride level. Osteogenesis was determined by measuring runt-related transcription factor 2 (Runx2) expression and alkaline phosphatase activity. For in vivo experiments, rats were injected with saline, BMSCs expressing GFP (GFP-BMSCs) or BMSCs expressing GFP-P-gp (MDR1-GFP-BMSCs). After dexamethasone induction, adipogenesis was determined by measuring PPAR-γ expression and fatty marrow, whereas osteogenesis was detected by measuring Runx2 expression, trabecular parameters and the mineral apposition rate, followed by evaluation of the incidence of ONFH. Overexpression of P-gp in BMSCs resulted in markedly decreased expression of adipogenic markers and increased expression of osteogenic markers. Compared with rats injected with saline, rats injected with GFP-BMSCs showed reduced ONFH, and the injected GFP-positive BMSCs attached to trabecular surfaces and exhibited an osteoblast-like morphology. Compared with the rats injected with BMSCs expressing GFP alone, rats injected with BMSCs overexpressing GFP and P-gp showed lower adipocytic variables, higher osteogenic variables and lower incidence of ONFH. Overexpression of P-gp inhibited BMSC adipogenesis and promoted osteogenesis, which reduced the incidence of steroid-induced ONFH.
authors.affiliation: Shanghai East Hospital of Tongji University, Shanghai, China.|Shanghai Tenth People's Hospital of Tongji University, Shanghai, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Han
authors.affiliation: Shanghai East Hospital of Tongji University, Shanghai, China.
authors.forename: Zengchun
authors.initials: Z
authors.lastname: Li
authors.affiliation: Shanghai Tenth People's Hospital of Tongji University, Shanghai, China. smztmp@126.com.|Shanghai First People's Hospital of Jiaotong University, Shanghai, China. smztmp@126.com.
authors.forename: Zhengdong
authors.initials: Z
authors.lastname: Cai
authors.affiliation: Zhongshan Hospital of Fudan University, Shanghai, China. yan1002@hotmail.com.
authors.forename: Zuoqin
authors.initials: Z
authors.lastname: Yan
authors.affiliation: Shanghai First People's Hospital of Jiaotong University, Shanghai, China.
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Hua
authors.affiliation: Shanghai East Hospital of Tongji University, Shanghai, China.
authors.forename: Chong
authors.initials: C
authors.lastname: Xu
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000378:metabolism*; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D005269:Femur / Q000187:drug effects / Q000473:pathology; D005271:Femur Head Necrosis / Q000139:chemically induced* / Q000473:pathology / Q000628:therapy*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D033581:Stem Cell Transplantation; D013256:Steroids / Q000009:adverse effects*; D019076:Transgenes
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D013256:Steroids; D049452:Green Fluorescent Proteins
keywords: P-glycoprotein; adipogenesis; bone marrow-derived multipotent stromal cell; osteogenesis; osteonecrosis