Induction of CXC chemokines in human mesenchymal stem cells by stimulation with secreted frizzled-related proteins through non-canonical Wnt signaling  

作　　者：David S Bischoff Jian-Hua Zhu Nalini S Makhijani Dean T Yamaguchi 

机构地区：[1]Research Service, VA Greater Los Angeles Healthcare System [2]Department of Medicine, David Geffen School of Medicine at UCLA

出　　处：《World Journal of Stem Cells》2015年第11期1262-1273,共12页世界干细胞杂志（英文版）（电子版）

基　　金：Supported by Merit Review Award from the United States,Department of Veterans Affairs Biomedical Laboratory Research and Development Service of the VA Office of Research and Development,No.I01BX000170

摘　　要：AIM: To investigate the effect of secreted frizzledrelated proteins(s FRPs) on CXC chemokine expression in human mesenchymal stem cells(h MSCs).METHODS: CXC chemokines such as CXCL5 and CXCL8 are induced in h MSCs during differentiation with osteogenic differentiation medium(OGM) and may be involved in angiogenic stimulation during bone repair. h MSCs were treated with conditioned medium(CM) from L-cells expressing non-canonical Wnt5 a protein, or with control CM from wild type L-cells, or directly with s FRPs for up to 10 d in culture. m RNA expression levels of both CXCL5 and CXCL8 were quantitated by real-time reverse transcriptase-polymerase chain reaction and secreted protein levels of these proteins determined by ELISA. Dose-(0-500 ng/m L) and time-response curves were generated for treatment with s FRP1. Signal transduction pathways were explored by western blot analysis with pan- or phosphorylation-specific antibodies, through use of specific pathway inhibitors, and through use of si RNAs targeting specific frizzled receptors(Fzd)-2 and 5 or thereceptor tyrosine kinase-like orphan receptor-2(Ro R2) prior to treatment with s FRPs. RESULTS: CM from L-cells expressing Wnt5 a, a noncanonical Wnt, stimulated an increase in CXCL5 m RNA expression and protein secretion in comparison to control L-cell CM. s FRP1, which should inhibit both canonical and non-canonical Wnt signaling, surprisingly enhanced the expression of CXCL5 at 7 and 10 d. Dickkopf1, an inhibitor of canonical Wnt signaling prevented the s FRPstimulated induction of CXCL5 and actually inhibited basal levels of CXCL5 expression at 7 but not at 10 d post treatment. In addition, all four s FRPs isoforms induced CXCL8 expression in a dose- and time-dependent manner with maximum expression at 7 d with treatment at 150 ng/m L. The largest increases in CXCL5 expression were seen from stimulation with s FRP1 or s FRP2. Analysis of mitogen-activated protein kinase signaling pathways in the presence of OGM showed s FRP1-induced phosphorylation of extracellAIM: To investigate the effect of secreted frizzledrelated proteins(s FRPs) on CXC chemokine expression in human mesenchymal stem cells(h MSCs).METHODS: CXC chemokines such as CXCL5 and CXCL8 are induced in h MSCs during differentiation with osteogenic differentiation medium(OGM) and may be involved in angiogenic stimulation during bone repair. h MSCs were treated with conditioned medium(CM) from L-cells expressing non-canonical Wnt5 a protein, or with control CM from wild type L-cells, or directly with s FRPs for up to 10 d in culture. m RNA expression levels of both CXCL5 and CXCL8 were quantitated by real-time reverse transcriptase-polymerase chain reaction and secreted protein levels of these proteins determined by ELISA. Dose-(0-500 ng/m L) and time-response curves were generated for treatment with s FRP1. Signal transduction pathways were explored by western blot analysis with pan- or phosphorylation-specific antibodies, through use of specific pathway inhibitors, and through use of si RNAs targeting specific frizzled receptors(Fzd)-2 and 5 or thereceptor tyrosine kinase-like orphan receptor-2(Ro R2) prior to treatment with s FRPs. RESULTS: CM from L-cells expressing Wnt5 a, a noncanonical Wnt, stimulated an increase in CXCL5 m RNA expression and protein secretion in comparison to control L-cell CM. s FRP1, which should inhibit both canonical and non-canonical Wnt signaling, surprisingly enhanced the expression of CXCL5 at 7 and 10 d. Dickkopf1, an inhibitor of canonical Wnt signaling prevented the s FRPstimulated induction of CXCL5 and actually inhibited basal levels of CXCL5 expression at 7 but not at 10 d post treatment. In addition, all four s FRPs isoforms induced CXCL8 expression in a dose- and time-dependent manner with maximum expression at 7 d with treatment at 150 ng/m L. The largest increases in CXCL5 expression were seen from stimulation with s FRP1 or s FRP2. Analysis of mitogen-activated protein kinase signaling pathways in the presence of OGM showed s FRP1-induced phosphorylation of extracell

关 键 词：CXC CHEMOKINES Mesenchymal stem cell OSTEOGENESIS Differentiation Wnt signaling pathway Frizzled-related protein FRIZZLED receptors 

分 类 号：R329.2[医药卫生—人体解剖和组织胚胎学]