Hyaluronic acid secretion by synoviocytes alters under cyclic compressive load in contracted collagen gels

Abstract

Knee osteoarthritis is a degenerative disease of diarthrodial joints. Biomechanical factors are considered as risk factors for the disease, the knee joint being normally subject to pressure. Some studies have examined the biomechanical environment of the knee joint in vitro. The aim of this study was to establish a culture model to mimic the knee joint environment. As a first step, synoviocytes induced contraction of threedimensional collagen gels. Next, contracted collagen gels containing synoviocytes underwent cyclical compression ranging from 0 to 40 kPa at a frequency of 1.0 Hz for 1.5, 3, 6 and 12 h using the FX-4000C TM Flexercell Ò Compression Plus TM System. RNA in collagen gels was extracted immediately after compression and mRNA expression levels of HAS genes were analyzed by quantitative RT-PCR. Culture medium was collected 48 h after compression and analyzed by agarose gel electrophoresis and cellulose acetate electrophoresis. Synoviocytes in contracted collagen gels were stimulated by cyclic compressive load. Long-term compressive stimulation led to the production of higher molecular weight hyaluronic acid, whereas, short-term, compressive stimulation increased the total amount of hyaluronic acid. Furthermore, mRNA expression levels of both HAS-1 and HAS-2 were significantly higher than without compression. Taken together, using this gel culture system, synoviocytes synthesized higher molecular weight hyaluronic acid and produced large quantities of hyaluronic acid through up-regulation of HAS gene expression. Therefore, the contracted collagen gel model will be a useful in vitro three-dimensional model of the knee joint.

Innovative Visualization and Quantification of Extracellular Vesicles Interaction with and Incorporation in Target Cells in 3D Microenvironments

“…Here, the 2D model confirmed the role of the HA matrix of EV-cell interaction for ACHs, as already shown for FLSs, suggesting a conserved mechanism of interaction [11]. The HA production was also demonstrated for both ACHs [37] and FLSs [38] in 3D systems, suggesting a conserved function, and in ACHs the expression of the major HA synthase HAS2 was shown to be comparable between 2D cultures and 3D fibrin-based matrix similar to the one used in this report. Nevertheless, aware of possible subtle differences in HA amount between the two cell culture systems herein analyzed that do not exactly reproduce the conditions used in the mentioned reports, the 3D model clearly showed that even after the removal of the hyaluronan coating, a fluorescent signal could be detected around the cells.…”

Endogenous production of hyaluronan, PRG4, and cytokines is sensitive to cyclic loading in synoviocytes

“…In this study, 5% and 20% strain of synoviocytes resulted in lower HAS3 expression, unlike static stretch, indicating that synoviocytes may be more responsive to cyclic stimulation as opposed to static stretch or a change in substrate stiffness. Our results on synoviocytes under cyclic loading are supported by prior work showing that cyclic compression of synoviocytes upregulates expression of HAS2 and HAS3 [31]. Together, this study in tension and others in compression suggest that hyaluronan turnover by synoviocytes is responsive to cyclic mechanical stimulation.…”

“…Exercise has been shown to improve proteoglycan and collagen content in cartilage [27][28][29] and decrease the severity of OA [30]. Cyclic compression has been shown to alter the expression of hyaluronan synthases in synoviocytes embedded within a collagen gel [31] and to alter the expression of inflammatory and matrix molecules [32][33][34][35], supporting the protective potential of mechanical stimulus on other tissues in the joint. These studies, however, have not measured changes in hyaluronan degradation or production of other components of synovial fluid, like PRG4.…”

Endogenous production of hyaluronan, PRG4, and cytokines is sensitive to cyclic loading in synoviocytes

“…Exercise has been shown to improve proteoglycan and collagen content in cartilage [27][28][29] and decrease the severity of OA [30]. Cyclic compression has been shown to alter the expression of hyaluronan synthases in synoviocytes embedded within a collagen gel [31] and to alter the expression of inflammatory and matrix molecules [32][33][34][35], supporting the protective potential of mechanical stimulus on other tissues in the joint. These studies, however, have not measured changes in hyaluronan degradation or production of other components of synovial fluid, like PRG4.…”