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¿是一种胸膜形态学，可调节组织修复表型，并且在纤维化修复病理学的发展中也起着重要作用。在眼睛的镜头中，由TGF介导的纤维化病理包括前囊膜下白内障（ASC）和后囊囊障碍（PCO）。在ASC和PCO中纤维化之前的细胞变化包括透镜上皮细胞（LEC）的增殖增加，在将上皮 - 间质转化（EMT）转化为肌纤维细胞中，涉及E-钙粘着蛋白的丧失并诱导A-Smooth肌肉肌动蛋白（Asma）表达。该项目的长期目标是确定TGF介导的信号，该信号改变了ASC期间晶状体上皮细胞的遗传组成和表型。使用先前开发的老鼠透镜培养模型，在该模型中，外源性TGF诱导ASC我们表明，用抑制基质金属蛋白酶（MMP）家族成员（MMPIS）抑制酶活性的药物的治疗可抑制TGF诱导的tgf诱导的天内变化。进一步的初步发现表明，通过脱落抑制MMP介导的E-钙粘着蛋白降解，可以测试MMPI可抑制镜头中TGF诱导的EMT和ASC的可检验假设。 RSMAD SMAD3是TGF信号传导的常见效应子，在镜头中已鉴定出来。但是，我们发现使用了两个不同的小鼠模型，在没有SMAD（在SMAD3 KO小鼠中）的情况下，TGF¿1可以在镜头中诱导EMT，这表明非独立的信号传导参与了ASC形成。其他发现表明，TGF¿诱导的ASC的假设涉及信号图映射激酶途径，特别是p38，该途径独立于SMAD3。为了检验这些假设，我们将利用体外TGF诱导的ASC的大鼠透镜模型以及一般修饰的小鼠，包括MMP-2，MMP-9和SMADS KO小鼠。 MMPI对E-钙粘蛋白表达和脱落的影响将使用RT-QPCR与激光捕获微分辨率，蛋白质印迹和免疫定位相结合。使用特定的PP38激酶抑制剂在体内和体外模型中将研究ASC形成中激活的P38MAPK的要求。这些数据将有助于定义控制ASC中EMT和纤维化的TGF介导的途径。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基因和信号传导机制相似，因此从这些研究中获得的信息也可能与这些疾病实体有关。