Mechanisms of Articular Cartilage Lubrication

描述(由申请人提供)：从培养的滑膜细胞中提取生物工程关节润滑剂这项拟议的修订旨在通过建立一个跨学科研究团队(BIRT)在组织工程和免疫学领域建立合作，来增加NIH R01 AR051565关节软骨润滑机制的父母资助。人体关节滑液的正常生物力学功能是通过润滑关节软骨，以较低的摩擦磨损促进相对组织表面的承载和相对运动。在体内，滑液润滑剂功能的缺陷可能导致损伤后退行性变、类风湿性关节炎和骨性关节炎的软骨侵蚀。在体外，当在生物反应器中通过关节运动进行机械调节时，具有正常滑液性质的液体可能会对软骨或骨关节结构(包括整个关节)的工程组织有用。作为润滑剂的滑液的一种成分是透明质酸(HA)。滑液中的HA主要由滑膜衬里的成纤维细胞样滑膜细胞贡献。在损伤和病变关节的滑液中，HA的浓度和相对分子质量的降低似乎与某些细胞因子的浓度升高有关。成纤维样滑膜细胞分泌透明质酸受IL-12和转化生长因子-21的调节，但其调节机制尚不清楚。了解在体外对HA分泌的免疫调节可能有助于生物反应器的生物工程，以产生模拟天然滑液的润滑剂功能和HA组成的溶液。这项研究的假设是，通过IL-12和转化生长因子-21对人类滑膜细胞HA分泌的免疫调节是通过调节特定的HA合成酶的信号通路，导致分泌的HA的水平和分子量分布改变，从而改变润滑功能。相关目的是评估(1)IL-12和转化生长因子-21调节人滑膜细胞HA分泌的机制：(1)在细胞因子单独或联合刺激后，通过检测HA合成酶(HAS)、HAS蛋白和具有细胞内转运功能的HA，以及与所选信号通路的抑制剂一起，评估IL-12和TGF-21对人滑膜细胞HA分泌的调节机制；(2)通过测定分泌的HA在“生物工程滑液”中的分子量分布和润滑功能，来评估细胞因子调节人滑膜细胞HA分泌的后果。

DESCRIPTION (provided by applicant): Bioengineering Joint Lubricants from Cultured Synoviocytes This proposed revision seeks to augment the parent grant, NIH R01 AR051565 Mechanisms of Articular Cartilage Lubrication, by Building an Interdisciplinary Research Team (BIRT) establishing collaboration in the fields of Tissue Engineering and Immunology. The synovial fluid of human joints normally functions biomechanically by lubricating articular cartilage, facilitating load-bearing and relative motion of apposing tissue surfaces with low friction and wear. In vivo, a deficiency in the lubricant function of synovial fluid may contribute to the cartilage erosion that occurs in post-injury degeneration, rheumatoid arthritis, and osteoarthritis. In vitro, a fluid with lubricant qualities like that of normal synovial fluid may be useful for engineering tissues in the form of cartilaginous or osteocartilaginous constructs including whole joints, when they are conditioned mechanically in a bioreactor by articulating motion. One component of synovial fluid that functions as a lubricant is hyaluronan (HA). The HA in synovial fluid is contributed primarily by the fibroblast-like synoviocytes of the synovial lining. In synovial fluids of injured and diseased joints, the decreased concentration and molecular weight of HA appear related to the elevated concentrations of certain cytokines. While HA secretion by fibroblast-like synoviocytes is regulated by IL-12 and TGF-21, the mechanisms of such regulation remain to be established. Knowledge of the immune regulation of HA secretion in vitro may facilitate the bioengineering of bioreactors to produce solutions that mimic the lubricant function and HA composition of native synovial fluid. The hypothesis of this study is that immune regulation, via IL-12 and TGF-21, of human synoviocyte HA secretion is through signaling pathways that modulate specific HA synthase enzymes, resulting in altered levels and molecular weight distributions of secreted HA, and, consequently, lubricant function. The associated aims are to assess (1) mechanisms of IL-12 and TGF-21 regulation of HA secretion in human synoviocytes by assessing HA synthase (HAS) mRNA, HAS protein, and HAS intracellular trafficking, after stimulation with cytokines, individually and in combination, and with inhibitors of selected signaling pathways, and (2) consequences of cytokine-regulated HA secretion in human synoviocytes by determining the molecular weight distribution and lubricating function of secreted HA in a "bioengineered synovial fluid."