The Physiological Role of Carbonic Anhydrases in the Ret

碳酸酐酶在视网膜中的生理作用

• 批准号: 7141784
• 负责人: sheldon s miller
• 金额: --
• 依托单位: NATIONAL EYE INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7141784
• 关键词: animal tissue; apical membrane; biological fluid transport; carbonate dehydratase; catalyst; enzyme activity; gene expression; human tissue; immunocytochemistry; protein localization; retinal pigment epithelium; tissue /cell culture; western blottings

Carbonic anhydrases (CAs) catalyze the reversible hydration of CO2 and are indirectly involved in the transport of water, bicarbonate, and protons. Twelve of the fourteen isozymes have been identified by RT-PCR and quantitative RT-PCR in human fetal RPE cells. We have determined the expression and subcellular distribution of CA II, IV, IX, and XIV in hfRPE cells by immunocytochemistry and Western blot. Immunocytochemical studies indicate that CA IV and CA IX are expressed at the apical surface of the RPE. CA II is an intracellular protein and CA XIV is mainly observed on the lateral membrane and is also present at the apical and basal membranes. The capacitance probe technique was used to study transepithelial fluid transport across monolayers of cultured human fetal and adult bovine RPE. Dorzolamide, a CA inhibitor of CA II and IX, caused a reversible decrease in fluid absorption across human fetal and adult bovine RPE when applied to the apical surface of the cells. This data indicates that CAs are important for regulating fluid transport across the RPE. Further studies will determine which of these CAs help regulate pH and absorption of fluid across the RPE.

碳酸氢酶(CA)催化二氧化碳的可逆水合反应，并间接参与水、碳酸氢盐和质子的运输。用RT-PCR和定量RT-PCR方法在人胎儿RPE细胞中鉴定了14种同工酶中的12种。我们用免疫细胞化学和免疫印迹法检测了CA II、IV、IX和XIV在hfRPE细胞中的表达和亚细胞分布。免疫细胞化学研究表明，CA IV和CA IX表达于RPE的顶面。CAⅡ是一种细胞内蛋白，CA XIV主要分布于侧膜，也存在于顶膜和基底膜。用电容探针技术研究了培养的人胎儿和成年牛RPE的跨上皮液跨膜转运。多唑胺是CA II和IX的CA抑制剂，当应用于细胞的顶端表面时，可导致人胎儿和成年牛RPE对液体的可逆性吸收减少。这一数据表明，CA对于调节RPE中的流体传输是重要的。进一步的研究将确定这些CA中的哪一个有助于调节RPE中流体的pH值和吸收。