Rao Vidhya R, Krishnamoorthy Raghu R, Yorio Thomas
Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA.
Exp Eye Res. 2008 Jun;86(6):886-94. doi: 10.1016/j.exer.2008.03.003. Epub 2008 Mar 12.
Endothelin-1 (ET-1), a potent vaso-active peptide, mediates extracellular matrix regulation resulting in an increase in collagen deposition in various cell types and tissues and has been proposed to play a key role in glaucoma pathology. The role of ET-1 in the regulation of extracellular matrix collagens at the level of optic nerve head is not known. In this study we have examined the role of ET-1 in extracellular matrix collagen regulation in primary cultures of human lamina cribrosa cells. Our hypothesis is that ET-1 increases remodeling of the ECM of cells of the lamina cribrosa. Such actions could contribute to the development of optic neuropathy. QPCR analysis revealed that ET-1 mediated an increase in mRNA levels of collagen type I alpha1 and collagen type VI alpha1 chains at all doses of ET-1 with a significant increase at 1nM and 10nM concentration in LC cells. A dose-dependent increase in collagen type I and type VI protein deposition and secretion was also observed by Western blot in response to ET-1 and was significant at 10nM and 100nM concentrations of ET-1. ET-1 increased the [3H] proline uptake in LC cells suggesting that ET-1 contributed to an increase in total collagen synthesis in LC cells. ET-1-mediated increase in collagen type I, type VI and total collagen synthesis was significantly blocked by the ET(A) receptor antagonist, BQ610, as well as with the ET(B) receptor antagonist, BQ788, suggesting the involvement of both receptor subtypes in ET-1 mediated collagen synthesis in LC cells. These results suggest that ET-1 regulates extracellular matrix collagen synthesis in LC cells and may contribute to ECM remodeling at the level of LC of POAG subjects who have elevated plasma and aqueous humor levels of endothelin-1.
内皮素-1（ET-1）是一种强效血管活性肽，可介导细胞外基质调节，导致各种细胞类型和组织中的胶原蛋白沉积增加，并被认为在青光眼病理过程中起关键作用。ET-1在视神经乳头水平调节细胞外基质胶原蛋白的作用尚不清楚。在本研究中，我们检测了ET-1在人筛板细胞原代培养物中对细胞外基质胶原蛋白调节的作用。我们的假设是，ET-1增加筛板细胞的细胞外基质重塑。这种作用可能有助于视神经病变的发展。定量聚合酶链反应（QPCR）分析显示，在所有ET-1剂量下，ET-1均介导I型胶原蛋白α1链和VI型胶原蛋白α1链的mRNA水平升高，在筛板细胞中，1nM和10nM浓度时显著升高。蛋白质免疫印迹法（Western blot）也观察到，响应ET-1时，I型和VI型胶原蛋白的蛋白质沉积和分泌呈剂量依赖性增加，在10nM和100nM的ET-1浓度时显著增加。ET-1增加了筛板细胞中[3H]脯氨酸的摄取，表明ET-1有助于筛板细胞中总胶原蛋白合成的增加。ET-1介导的I型、VI型胶原蛋白和总胶原蛋白合成增加被ET(A)受体拮抗剂BQ610以及ET(B)受体拮抗剂BQ788显著阻断，这表明两种受体亚型均参与ET-1介导的筛板细胞胶原蛋白合成。这些结果表明，ET-1调节筛板细胞中的细胞外基质胶原蛋白合成，并可能导致原发性开角型青光眼（POAG）患者筛板水平的细胞外基质重塑，这些患者的血浆和房水中内皮素-1水平升高。
