Intercellular communication in the lens

摘要 连接蛋白通道提供的缝隙连接通讯在出生后是必需的 镜头生长和透明度。CX46和CX50编码基因的靶向缺失 导致小鼠白内障。同样，CX50和Cx46基因的突变都会导致 人类和小鼠的各种类型的白内障。联轴器的变化已经被 建议用于糖尿病和老年性白内障的发病，但很少有 直接将缝隙连接耦合与这些病理生理条件联系起来的研究。 最近，我们发现在分子渗透性方面存在差异 频道由Cx46、CX50和Cx43组成。在这项建议中，我们将继续追求 电生理研究以了解通道类型的多样性是如何形成的 缝隙连接蛋白对晶状体功能的影响及其改变如何导致先天性 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CX46和CX50间隙连接在 晶状体内维持足够浓度的重要代谢物 纤维细胞。我们将使用电生理和生化分析来研究 分子在体外和体内的渗透。我们还将确定CX50和 导致先天性白内障的Cx46突变有分子上的变化 渗透性。其次，我们将确定耦合电导和/或 渗透性会随着衰老和氧化应激而改变。质谱学方法将会 用来识别连接蛋白在衰老过程中的修饰 白内障的发生。改性对GaP电导和磁导率的影响 连接将使用电生理学方法进行评估。

Abstract 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.