Lee Sang Yang, Nakagawa Toshiyuki, Reddi A Hari
Center for Tissue Regeneration and Repair, Department of Orthopaedic Surgery, University of California-4635 Second Avenue, Room 2000, Sacramento, CA 95817, USA.
Biochem Biophys Res Commun. 2008 Nov 7;376(1):148-53. doi: 10.1016/j.bbrc.2008.08.138. Epub 2008 Sep 5.
Superficial zone protein (SZP) is a key mediator of boundary lubrication of articular cartilage in joints. In this investigation, we made the unexpected discovery that SZP was expressed in infrapatellar fat pad (IFP) from bovine knee. Quantitative analysis of secreted proteins in the medium of the IFP stromal cells demonstrated a significant stimulation by TGF-beta1 and BMP-7. Real-time PCR analysis revealed the SZP expression was up-regulated by TGF-beta1 and BMP-7. Chondrogenically differentiated IFP progenitor cells were stimulated by TGF-beta1 and BMP-7 to synthesize and secrete SZP. SZP mRNA was significantly up-regulated by chondrogenic induction for 21 days. These findings indicate that the stimulation of SZP expression by TGF-beta and BMP-7 may lead to functional improvement of damaged intraarticular tissues and that IFP progenitor cells may be a potential useful source for inducing superficial zone of articular cartilage by tissue engineering for regeneration of damaged articular cartilage due to osteoarthritis.
表面区蛋白（SZP）是关节中关节软骨边界润滑的关键介质。在本研究中，我们意外发现SZP在牛膝关节的髌下脂肪垫（IFP）中表达。对IFP基质细胞培养基中分泌蛋白的定量分析表明，转化生长因子-β1（TGF-β1）和骨形态发生蛋白-7（BMP-7）对其有显著刺激作用。实时定量聚合酶链反应（Real-time PCR）分析显示，TGF-β1和BMP-7可上调SZP的表达。TGF-β1和BMP-7刺激软骨分化的IFP祖细胞合成并分泌SZP。软骨诱导21天后，SZP信使核糖核酸（mRNA）显著上调。这些发现表明，TGF-β和BMP-7对SZP表达的刺激可能会导致受损关节内组织功能改善，并且IFP祖细胞可能是通过组织工程诱导关节软骨表面区以再生因骨关节炎受损的关节软骨的潜在有用来源。
