title: Effects of CD14 macrophages and proinflammatory cytokines on chondrogenesis in osteoarthritic synovium-derived stem cells.
abstract: We investigated the effects of CD14 macrophages and proinflammatory cytokines on chondrogenic differentiation of osteoarthritic synovium-derived stem cells (SDSCs). Osteoarthritic synovial fluid was analyzed for interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6. Levels of stem cell surface markers in osteoarthritic SDSCs were evaluated using flow cytometry. CD14-negative cells were obtained using magnetically activated cell sorting. We compared chondrogenic potentials between whole cells and CD14-negative cells in CD14(low) cells and CD14(high) cells, respectively. To assess whether nuclear factor-κB (NF-κB) and CCAAT/enhancer-binding protein β (C/EBPβ) modulate IL-1β-induced alterations in chondrogenic potential, we performed small interfering RNA transfection. We observed a significant correlation between the CD14 ratio in osteoarthritic SDSCs and IL-1β and TNF-α in osteoarthritic synovial fluid. Phenotypic characterization of whole cells and CD14-negative cells showed no significant differences in levels of stem cell markers. mRNA expression of type II collagen was higher in CD14-negative cell pellets than in whole cell pellets. Immunohistochemical staining indicated higher levels of type II collagen in the CD14-negative cell pellets of CD14(high) cells than in whole cell pellets of CD14(high) cells. As expected, IL-1β and TNF-α significantly inhibited the expression of chondrogenic-related genes in SDSCs, an effect which was antagonized by knockdown of NF-κB and C/EBPβ. Our results suggest that depletion of CD14(+) synovial macrophages leads to improved chondrogenic potential in CD14(high) cell populations in osteoarthritic SDSCs, and that NF-κB (RelA) and C/EBPβ are critical factors mediating IL-1β-induced suppression of the chondrogenic potential of human SDSCs.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University College of Medicine , Seoul, South Korea .
authors.forename: Sun Ae
authors.initials: SA
authors.lastname: Han
authors.forename: Sahnghoon
authors.initials: S
authors.lastname: Lee
authors.forename: Sang Cheol
authors.initials: SC
authors.lastname: Seong
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Lee
mesh_terms: D000368:Aged; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000235:genetics; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D020219:Chondrogenesis; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D055785:Gene Knockdown Techniques; D006801:Humans; D018950:Lipopolysaccharide Receptors; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology; D013234:Stem Cells / Q000378:metabolism* / Q000473:pathology; D013583:Synovial Membrane / Q000378:metabolism* / Q000473:pathology; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism
chemical_list: D000943:Antigens, Differentiation; D022782:CCAAT-Enhancer-Binding Protein-beta; C545012:CEBPB protein, human; D016207:Cytokines; D018950:Lipopolysaccharide Receptors; C498143:RELA protein, human; D051996:Transcription Factor RelA