Role of Matrix Metalloproteinases in Subcapsular Cataract Formation

基质金属蛋白酶在囊下白内障形成中的作用

• 批准号: 7024380
• 负责人: Judith A West-Mays
• 金额: $ 21.6万
• 依托单位: MCMASTER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7024380
• 关键词: cadherins; cataract; lens; model; role

DESCRIPTION: The cytokine TGF¿ is a pleotropic morphogen that modulates the tissue repair phenotype and also plays an important role in the development of fibrotic repair pathologies. In the lens of the eye, fibrotic pathologies mediated by TGF¿ include anterior subcapsular cataracts (ASC) and posterior capsular opacification (PCO). The cellular changes that precede fibrosis in ASC and PCO include an increased proliferation of lens epithelial cells (LECs), which under go an epithelial-mesenchymal transformation (EMT) into myofibroblasts, involving loss of E-cadherin and induced a-smooth muscle actin (aSMA) expression. The long-term goal of this project is to determine the TGF¿-mediated signals, which alter the genetic makeup and phenotype of lens epithelial cells during ASC. Using a previously developed rat lens culture model in which exogenous TGF¿ induces ASC we have shown that treatment with agents that inhibit enzymatic activity of Matrix Metalloproteinase (MMP) family members (MMPIs) suppresses the TGF¿-induced cataractous changes. Further preliminary findings suggest the testable hypothesis that MMPIs act to inhibit TGF¿-induced EMT and ASC in the lens by suppressing MMP-mediated E-cadherin degradation by shedding. The RSmad, Smad3, is a common effector of TGF¿ signaling, which has been identified in the lens. However, we have found using two different mouse models that in the absence of SmadS (in Smad3 KO mice) TGF¿1 can induce EMT in the lens, demonstrating the involvement of Smad3-independent signaling in ASC formation. Additional findings suggest that the hypothesis that TGF¿-induced ASC involves signaling MAP kinase pathways, specifically p38, which act independently of Smad3. To test these hypotheses we will utilize the in vitro TGF¿-induced rat lens model of ASC, as well as genetically modified mice, including MMP-2, MMP-9 and SmadS KO mice. The effect of MMPIs on E-cadherin expression and shedding will be further examined using RT-QPCR in combination with laser capture microdissection, western blotting and immunolocalization. The requirement for activated p38MAPK in ASC formation will be investigated in both the in vivo and in vitro models using specific Pp38 kinase inhibitors. These data will aid in defining the TGF¿-mediated pathways controlling EMT and fibrosis in ASC. Furthermore, since the genes and signaling mechanisms in ASC formation are similar to those which occur in other fibrotic diseases and cancer, the information gained from these studies in the lens may also have relevance to these disease entities.

描述：细胞因子 TGF¿是一种多效性形态发生素，可调节组织修复表型，并且在眼睛晶状体纤维化病理学的发展中发挥重要作用，由 TGF 介导。包括前囊膜下白内障 (ASC) 和后囊膜混浊 (PCO) ASC 和 PCO 纤维化之前的细胞变化包括晶状体上皮细胞 (LEC) 增殖增加，并发生上皮间质转化 (EMT) 为肌成纤维细胞。 ，涉及 E-钙粘蛋白的损失和诱导的 a-平滑肌肌动蛋白 (aSMA) 表达。该项目的长期目标是确定 TGF¿ -介导的信号，使用先前开发的大鼠晶状体培养模型，其中外源性TGF¿诱导 ASC 我们已经证明，用抑制基质金属蛋白酶 (MMP) 家族成员 (MMPI) 酶活性的药物治疗可以抑制 TGF¿进一步的初步研究结果提出了可检验的假设，即 MMPI 具有抑制 TGF 的作用。 - 通过脱落抑制 MMP 介导的 E-钙粘蛋白降解，诱导晶状体中的 EMT 和 ASC RSmad、Smad3 是 TGF 的常见效应器。然而，我们使用两种不同的小鼠模型发现，在缺乏 SmadS（Smad3 KO 小鼠）的情况下，TGF¿ 1 可以诱导晶状体中的 EMT，证明 Smad3 独立信号传导参与 ASC 形成。诱导的 ASC 涉及 MAP 激酶信号通路，特别是 p38，其作用独立于 Smad3。为了测试这些假设，我们将利用体外 TGF¿诱导的 ASC 大鼠晶状体模型以及转基因小鼠，包括 MMP-2、MMP-9 和 SmadS KO 小鼠。将使用 RT-QPCR 与结合进一步检查 MMPI 对 E-钙粘蛋白表达和脱落的影响。将使用特定的 Pp38 激酶抑制剂在体内和体外模型中研究 ASC 形成中激活的 p38MAPK 的需求。帮助定义 TGF¿此外，由于 ASC 形成中的基因和信号传导机制与其他纤维化疾病和癌症中发生的相似，因此从晶状体中的这些研究中获得的信息也可能与这些疾病相关。实体。