Intercellular communication in the lens

描述(申请人提供)：由连接蛋白通道提供的缝隙连接通讯是出生后晶状体生长和透明所必需的。编码CX46和CX50的基因的靶向缺失会导致小鼠白内障。同样，CX50和Cx46基因的突变会导致人类和小鼠多种类型的白内障。联结的改变被认为是糖尿病和老年性白内障发生的基础，但很少有研究直接将缝隙连接联结与这些病理生理状况联系起来。最近，我们发现通过由Cx46、CX50和Cx43组成的通道的分子通透性存在差异。在这个方案中，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晶状体功能，以及它们的变化如何导致先天性和老年性白内障，通过追求以下两个目标。在目标1中，我们将确定晶状体中Cx46和CX50缝隙连接所提供的偶联在维持内纤维细胞中重要代谢物足够浓度方面的重要性。我们将使用电生理和生化方法来研究分子在体外和体内的渗透。我们还将确定导致先天性白内障的CX50和Cx46突变是否在分子渗透性方面发生了变化。其次，我们将确定偶联电导和/或通透性是否随衰老和氧化应激而改变。质谱学方法将被用来确定连接蛋白在衰老和白内障形成过程中的修饰。将使用电生理学方法评估修饰对缝隙连接的电导和磁导率的影响。 与公共健康相关：细胞之间的通讯是由一种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，这是世界上导致失明的主要原因。我们的研究旨在了解这些蛋白在老年性白内障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.