Sassi N, Laadhar L, Allouche M, Zandieh-Doulabi B, Hamdoun M, Klein-Nulend J, Makni S, Sellami S
Immuno-Rheumatology Research Laboratory, Department of Rheumatology, La Rabta Hospital, University of Tunis-El Manar.
Biotech Histochem. 2014 Jan;89(1):29-40. doi: 10.3109/10520295.2013.811285. Epub 2013 Aug 1.
Osteoarthritis is the most prevalent form of arthritis in the world. Certain signaling pathways, such as the wnt pathway, are involved in cartilage pathology. Osteoarthritic chondrocytes undergo morphological and biochemical changes that lead to chondrocyte de-differentiation. We investigated whether the Wnt pathway is involved in de-differentiation of human articular chondrocytes in vitro. Human articular chondrocytes were cultured for four passages in the presence or absence of IL-1 in monolayer or micromass culture. Changes in cell morphology were monitored by light microscopy. Protein and gene expression of chondrocyte markers and Wnt pathway components were determined by Western blotting and qPCR after culture. After culturing for four passages, chondrocytes exhibited a fibroblast-like morphology. Collagen type II and aggrecan protein and gene expression decreased, while collagen type I, matrix metalloproteinase 13, and nitric oxide synthase expressions increased. Wnt molecule expression profiles changed; Wnt5a protein expression, the Wnt target gene, c-jun, and in Wnt pathway regulator, sFRP4 increased. Treatment with IL-1 caused chondrocyte morphology to become more filament-like. This change in morphology was accompanied by extinction of col II expression and increased col I, MMP13 and eNOS expression. Changes in expression of the Wnt pathway components also were observed. Wnt7a decreased significantly, while Wnt5a, LRP5, β-catenin and c-jun expressions increased. Culture of human articular chondrocytes with or without IL-1 not only induced chondrocyte de-differentiation, but also changed the expression profiles of Wnt components, which suggests that the Wnt pathway is involved in chondrocyte de-differentiation in vitro.
骨关节炎是世界上最常见的关节炎形式。某些信号通路，如Wnt通路，参与软骨病理过程。骨关节炎软骨细胞会经历形态和生化变化，导致软骨细胞去分化。我们研究了Wnt通路是否参与体外人关节软骨细胞的去分化过程。人关节软骨细胞在单层或微团培养中，在有或无白细胞介素-1（IL-1）的情况下培养四代。通过光学显微镜监测细胞形态变化。培养后，通过蛋白质印迹法和定量聚合酶链反应（qPCR）测定软骨细胞标志物和Wnt通路成分的蛋白质和基因表达。培养四代后，软骨细胞呈现成纤维细胞样形态。II型胶原蛋白和聚集蛋白聚糖的蛋白质和基因表达下降，而I型胶原蛋白、基质金属蛋白酶13和一氧化氮合酶的表达增加。Wnt分子表达谱发生变化；Wnt5a蛋白表达、Wnt靶基因c-jun以及Wnt通路调节因子sFRP4增加。用IL-1处理导致软骨细胞形态变得更像丝状。这种形态变化伴随着II型胶原表达的消失以及I型胶原、MMP13和内皮型一氧化氮合酶（eNOS）表达的增加。还观察到Wnt通路成分表达的变化。Wnt7a显著下降，而Wnt5a、低密度脂蛋白受体相关蛋白5（LRP5）、β-连环蛋白和c-jun的表达增加。有或无IL-1培养人关节软骨细胞不仅诱导软骨细胞去分化，还改变了Wnt成分的表达谱，这表明Wnt通路参与体外软骨细胞的去分化过程。
