Modulation of the Epithelial Sodium Channel by Proteases and Peptide Inhibitors

蛋白酶和肽抑制剂对上皮钠通道的调节

基本信息

批准号：
7995259
负责人：
Christopher John Passero
金额：
$ 2.94万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-07-01 至 2010-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7995259
关键词：
Affect Aldosterone Amino Acids Apical Blood Pressure Bowman&apos s space Cell membrane Cells Charge Cleaved cell Clinical Collecting Cell Development Disease Distal Duct (organ) structure Edema Epithelial Equilibrium Essential Hypertension Event Fluid Balance Generations Homeostasis Hormones Human Hyperaldosteronism Hypertension Kidney Kidney Diseases Kidney Failure Leg Liquid substance Matrix Metalloproteinases Mentors Morbidity - disease rate Mutate Myocardial Infarction Nephrons Nephrotic Syndrome Oocytes Patients Peptide Hydrolases Peptides Peripheral Physiological Plasmin Play Probability Process Protease Inhibitor Regulation Research Risk Factors Role Serine Protease Site Sodium Sodium Channel Sodium Chloride Stroke Swelling Symptoms Syndrome System Time Work Xenopus laevis Xenopus oocyte absorption apical membrane blood pressure regulation collecting tubule structure combat epithelial Na+ channel extracellular human PRSS8 protein human disease inhibitor/antagonist mortality mutant new therapeutic target prevent research study synthetic peptide therapeutic target trans-Golgi Network urinary

项目摘要

DESCRIPTION (provided by applicant): Renal sodium reabsorption in the principal cells of the collecting duct occurs across the epithelial, sodium channel (ENaC) and affects extracellular volume homeostatsis and blood pressure control. In the kidney, two distinct pools of epithelial sodium channels are inserted into the apical membrane of the principal cells of the collecting duct. One pool of channels undergoes maturation and activation by proteases in the trans-Golgi network. The other pool avoids maturation and remains inactive. During maturation, the serine proteases furin and prostasin cleave inhibitory residues from the alpha and gamma subunits of ENaC, activating the channel. The inactive pool may be a target of proteases in pathophysiologic states, like hypertension and nephrotic syndrome. Other serine proteases besides furin and prostasin can activate these channels. Recent evidence suggests plasmin and matrix metalloproteinases activate ENaC. The specific aims of the proposed research are: (1) to identify the key regions and residues within inhibitory peptides derived from the gamma subunit required for ENaC inhibition, and (2) to define the role of plasmin and matrix metalloproteinases in the regulation of ENaC activity. The Xenopus laevis oocyte expression system will be used for these studies. Serial deletions in subunits with mutated furin- and prostasin- sites will be generated so they are not cleaved during maturation. Deletions that result in enhanced ENaC activity in Xenopus oocytes will identify putative inhibitory regions. The effects of synthetic peptide, corresponding to an identified inhibitory region, on ENaC activity will be examined. Synthetic peptides with scrambles and substitutions will determine the importance of specific amino acids, charge, and sequence of the inhibitory region. The effect of plasmin and MMPs on ENaC activity will be examined. Analysis of peptide inhibitors and protease activators of ENaC may provide new potential therapeutic targets for hypertension and nephrotic syndrome. A salt transporter in the kidney helps the body manage fluid balance and prevent fluid retention. Abnormalities in the transporter occur in some forms of high blood pressure and may be involved in a kidney disease that causes leg swelling. Understanding the activators and inhibitors of this channel may help identify new therapies to combat these diseases.

描述（由申请人提供）：收集导管的主要细胞中的肾钠重吸收发生在上皮，钠通道（ENAC）上，并影响细胞外体积体内稳态和血压控制。在肾脏中，将两个不同的上皮钠通道池插入收集管的主要细胞的顶膜中。一个通道池在反式高尔基网络中通过蛋白酶经历成熟和激活。另一个池避免成熟并保持不活跃。在成熟过程中，丝氨酸蛋白酶脂蛋白和前列腺素切割抑制性残基从ENAC的α和伽马亚基中激活，从而激活了通道。非活性池可能是病理生理状态中蛋白酶的靶标，例如高血压和肾病综合征。除脂蛋白和前列腺素外，其他丝氨酸蛋白酶还可以激活这些通道。最近的证据表明纤溶酶和基质金属蛋白酶激活ENAC。拟议研究的具体目的是：（1）确定从ENAC抑制所需的γ亚基中衍生的抑制性肽中的关键区域和残基，以及（2）定义纤溶酶和基质金属蛋白酶在ENAC活性调节中的作用。这些研究将使用Laevis卵母细胞表达系统。将产生具有突变液和前列腺素位点的亚基中的串行缺失，因此在成熟过程中不会裂解它们。导致爪蟾卵母细胞中ENAC活性增强的缺失将确定推定的抑制区域。将检查与鉴定抑制区域对应于ENAC活性的合成肽的影响。与争夺和取代的合成肽将确定抑制区域的特定氨基酸，电荷和序列的重要性。将检查纤溶酶和MMP对ENAC活性的影响。 ENAC的肽抑制剂和蛋白酶活化剂的分析可能为高血压和肾病综合征提供新的潜在治疗靶标。肾脏中的盐转运蛋白有助于人体管理液体平衡并防止液体保留。转运蛋白异常以某些形式的高血压出现，可能参与导致腿部肿胀的肾脏疾病。了解该渠道的激活因子和抑制剂可能有助于确定对抗这些疾病的新疗法。