Intercellular communication in the lens

摘要 由连接蛋白通道提供的间隙连接通讯是出生后 透镜生长和透明度。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基因的突变引起了一种新的免疫缺陷。 人类和小鼠的各种类型的白内障。耦合的变化已经 被认为是糖尿病和老年白内障的病因，但很少有 直接将缝隙连接偶联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， 由Cx46、Cx 50和Cx43组成的通道。在这一建议中，我们将继续追求 电生理学研究，以了解通道类型的多样性是如何形成的 连接蛋白影响透镜功能以及它们的改变如何导致先天性 和年龄相关的白内障通过追求以下两个目标。在目标1中，我们 确定由Cx46和Cx 50间隙连接提供的偶联的重要性， 透镜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化分析来研究 分子在体外和体内的渗透。我们还将确定Cx 50和 导致先天性白内障的Cx46突变具有分子水平的改变， 磁导率其次，我们将确定耦合电导和/或 渗透性随着老化和氧化应激而改变。质谱方法将 用于识别连接蛋白随老化和老化过程中的修饰 白内障形成改性对气隙电导率和磁导率的影响 将使用电生理学方法评估连接。

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.