Intercellular communication in the lens

描述（由申请方提供）：出生后透镜生长和透明需要连接蛋白通道提供的缝隙连接通讯。编码Cx46和Cx 50的基因的靶向缺失导致小鼠白内障。类似地，Cx 50和Cx46基因的突变在人类和小鼠中引起各种类型的白内障。偶联的改变被认为是糖尿病和老年白内障的基础，但很少有研究直接将缝隙连接偶联与这些病理生理条件联系起来。最近，我们发现通过由Cx46、Cx 50和Cx43组成的通道的分子渗透性存在差异。在本提案中，我们将继续进行电生理学研究，以了解连接蛋白形成的通道类型的多样性如何影响透镜功能，以及它们的改变如何导致先天性和年龄相关性白内障，实现以下两个目标。在目的1中，我们将确定耦合提供的重要性，在透镜中的Cx46和Cx 50间隙连接在维持足够浓度的重要代谢物在内部纤维细胞。我们将使用电生理和生物化学测定来研究分子在体外和体内的渗透。我们还将确定引起先天性白内障的Cx 50和Cx46突变是否具有分子渗透性的改变。其次，我们将确定耦合电导和/或渗透性是否随着衰老和氧化应激而改变。质谱方法将被用来确定修改连接蛋白与老化和白内障。将使用电生理学方法评估修饰对间隙连接的电导和渗透性的影响。 公共卫生相关性：细胞之间的通讯是由称为连接蛋白的蛋白质介导的。这些连接蛋白的突变导致了人类的许多疾病，包括白内障，这是世界上失明的主要原因。我们的研究旨在了解这些蛋白质在老年性和先天性白内障中的重要性。

DESCRIPTION (provided by applicant): Gap junctional communication provided by connexin channels is required for postnatal lens growth and transparency. Targeted deletions of genes encoding Cx46 and Cx50 lead to cataracts in mice. Similarly, mutations in both Cx50 and Cx46 genes cause a variety of cataract types in both humans and mice. Alterations in coupling have been suggested to underlie cataracts that occur with diabetes and with age, but there are few studies directly linking gap junctional coupling to these pathophysiological conditions. More recently, we found that there are differences in the molecular permeability through channels made of Cx46, Cx50 and Cx43. In this proposal, we will continue to pursue electrophysiological studies to understand how the diversity in channel types formed by connexin proteins influences lens function and how their alteration leads to congenital and age-related cataracts by pursuing the following two Aims. In Aim 1, we will determine the importance of coupling provided by Cx46 and Cx50 gap junctions in the lens in the maintenance of adequate concentrations of important metabolites in inner fiber cells. We will use electrophysiological and biochemical assays to study the permeation of molecules in vitro and in vivo. We will also determine whether Cx50 and Cx46 mutations that cause congenital cataracts have alterations in molecular permeability. Second, we will determine whether coupling conductance and/or permeability is altered with aging and oxidative stress. Mass spectrometric methods will be employed to identify modifications to connexins with aging and during cataractogenesis. The effect of modifications on conductance and permeability of gap junctions will be assessed using electrophysiological methods. PUBLIC HEALTH RELEVANCE: Communication between cells is mediated by proteins called connexins. Mutations in these connexin proteins are responsible for a number of diseases in humans, including cataracts, the leading cause of blindness in the world. Our studies are aimed at understanding the importance of these proteins in both age-onset and congenital cataracts.