title: Adipose-derived stem cells induce autophagic activation and inhibit catabolic response to pro-inflammatory cytokines in rat chondrocytes.
abstract: Adipose-derived stem cells (ADSCs) have been demonstrated to have an anti-apoptosis effect on chondrocytes; However, their effect on autophagic activation remains unclear. We sought to explore whether ADSCs can activate autophagy and inhibit IL-1β- and lipopolysaccharide (LPS)-induced catabolism in chondrocytes.
  
  
  
  ADSCs and chondrocytes were collected from SD rats. The biologic characteristics of ADSCs were analyzed by flow cytometric analysis, Oil red O and Alizarin Red staining. Autophagic level and autophagic flux were revealed by Western blotting for LC3-II and SQSTM1/P62, MDC (monodansylcadaverine) staining and mRFP-GFP-LC3 analysis. The mTOR pathway was investigated by Western blotting for p-mTOR. The mRNA level of matrix metalloproteinases (MMPs) and thrombospondin motifs (ADAMTSs) was detected by real-time PCR.
  
  
  
  The typical surface markers and differentiation potentials of ADSCs were proved. ADSCs enhanced the expression of LC3-II/LC3-I and reduced SQSTM1 levels in IL-1β-induced chondrocytes after 24 and 48 h co-culturing and in LPS-induced chondrocytes after 48 h co-culturing respectively. mRFP-GFP-LC3 analysis suggested that autophagosomes and autolysosomes were formed earlier in IL-1β-treated chondrocytes than in LPS-treated chondrocytes. Bafilomycin A1 treatment further increased the LC3-II/LC3-I level in chondrocytes in co-culture with ADSCs. The mTOR pathway was inhibited in the chondrocytes in co-culture with ADSCs. Finally, ADSCs inhibited the increase of MMPs and ADAMTSs in chondrocytes induced by IL-1β and LPS.
  
  
  
  ADSCs seem able to activate autophagy and inhibit catabolism in chondrocytes in an inflammation environment, and the mTOR pathway might be involved in the autophagy activation.
authors.affiliation: Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Li-Bo
authors.initials: LB
authors.lastname: Jiang
authors.affiliation: Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Soomin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Qin-Tong
authors.initials: QT
authors.lastname: Xu
authors.affiliation: Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Meng
authors.affiliation: Department of Orthopedic Surgery, Zhongshan Hospital, Fudan University, Shanghai, China. Electronic address: zhang.jian@zs-hospital.sh.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019902:Chondrocytes; D016207:Cytokines; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells
chemical_list: D016207:Cytokines
keywords: Adipose-derived stem cells; Autophagy; Chondrocyte; IL-1β; mTOR