Stimulation of Superficial Zone Protein/Lubricin/PRG4 by Transforming Growth Factor-β in Superficial Zone Articular Chondrocytes and Modulation by Glycosaminoglycans
Stimulation of Superficial Zone Protein/Lubricin/PRG4 by Transforming Growth Factor-β in Superficial Zone Articular Chondrocytes and Modulation by Glycosaminoglycans
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DOI：
10.1089/ten.tea.2014.0381
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发表时间：
2015-07-01
影响因子：
4.1
通讯作者：
Reddi, A. Hari
中科院分区：
文献类型：
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作者：
Cuellar, Araceli;Reddi, A. Hari
表浅区蛋白（SZP），又称润滑素和蛋白聚糖4（PRG 4），在关节软骨的边界润滑中起重要作用，并受转化生长因子（TGF）-β的调节。在这里，我们评估的作用，细胞表面糖胺聚糖（GAG）在TGF-1刺激SZP/润滑素/PRG 4在浅区关节软骨细胞。我们利用原代单层浅区关节软骨细胞培养物，并在存在或不存在硫酸乙酰肝素（HS）、肝素和硫酸软骨素（CS）的情况下，用不同浓度的TGF-1对其进行处理。在TGF-1刺激之前，通过用肝素酶I或软骨素酶-ABC预处理去除细胞表面GAG。SZP/润滑素/PRG 4在培养基中响应于用TGF-1和各种外源性GAG刺激的积累通过免疫印迹证明，并通过酶联免疫吸附测定定量。我们发现，TGF-1和外源性HS增强SZP积累的浅区软骨细胞在表面糖胺聚糖的存在下。当TGF-1浓度为1 ng/mL时，外源性肝素抑制SZP的积累，而外源性CS促进SZP的积累。在外源性肝素和CS存在下，浅表区软骨细胞表面上的GAG的酶促消耗增强了TGF-1刺激SZP积累的能力。总的来说，这些结果表明，浅区关节软骨细胞表面的GAG影响对TGF-1和外源性GAG的反应，以刺激SZP积累。细胞表面糖胺酸调节表浅区软骨细胞对TGF-1和外源性HS的反应。
Superficial zone protein (SZP), also known as lubricin and proteoglycan 4 (PRG4), plays an important role in the boundary lubrication of articular cartilage and is regulated by transforming growth factor (TGF)-. Here, we evaluate the role of cell surface glycosaminoglycans (GAGs) during TGF-1 stimulation of SZP/lubricin/PRG4 in superficial zone articular chondrocytes. We utilized primary monolayer superficial zone articular chondrocyte cultures and treated them with various concentrations of TGF-1, in the presence or absence of heparan sulfate (HS), heparin, and chondroitin sulfate (CS). The cell surface GAGs were removed by pretreatment with either heparinase I or chondroitinase-ABC before TGF-1 stimulation. Accumulation of SZP/lubricin/PRG4 in the culture medium in response to stimulation with TGF-1 and various exogenous GAGs was demonstrated by immunoblotting and quantitated by enzyme-linked immunosorbent assay. We show that TGF-1 and exogenous HS enhanced SZP accumulation of superficial zone chondrocytes in the presence of surface GAGs. At the dose of 1ng/mL of TGF-1, the presence of exogenous heparin inhibited SZP accumulation whereas the presence of exogenous CS stimulated SZP accumulation in the culture medium. Enzymatic depletion of GAGs on the surface of superficial zone chondrocytes enhanced the ability of TGF-1 to stimulate SZP accumulation in the presence of both exogenous heparin and CS. Collectively, these results suggest that GAGs at the surface of superficial zone articular chondrocytes influence the response to TGF-1 and exogenous GAGs to stimulate SZP accumulation. Cell surface GAGs modulate superficial zone chondrocytes' response to TGF-1 and exogenous HS.