Role of piezo channels in intercalated cells

压电通道在嵌入细胞中的作用

• 批准号: 10598161
• 负责人: Thomas R Kleyman
• 金额: $ 60.45万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10598161
• 关键词: Actins; Adult; Affect; Aldosterone; Apical; Attention; Bicarbonates; Binding; Brush Border; Calcium; Cations; Cell Differentiation process; Cell membrane; Cell physiology; Cells; Cilia; Coupled; Cytoskeleton; Development; Diameter; Diet; Dietary Potassium; Disease; Distal; Duct (organ) structure; Epithelial Cells; Equation; Event; Excretory function; Exhibits; Extracellular Matrix; Family; Genetic; Intake; Intercalated Cell; Ion Channel; Kidney; Life; Link; Liquid substance; Location; Maintenance; Mechanics; Mediating; Membrane; Molecular; Mus; Natural Immunity; Nephrons; PKD2 protein; Pathway interactions; Perfusion; Phase; Piezo 1 ion channel; Piezo ion channels; Potassium; Radial; Reporting; Role; Stretching; Testing; Tubular formation; Urine; Variant; Work; absorption; basolateral membrane; cell type; epithelial Na+ channel; experimental study; extracellular; inhibitor; large-conductance calcium-activated potassium channels; mechanical force; mechanotransduction; member; neonatal mice; new therapeutic target; novel; patch clamp; polycystic kidney disease 1 protein; postnatal; response; sensor; shear stress; transmission process; urinary

Intercalated cells (ICs) in the aldosterone-sensitive distal nephron (ASDN) secrete H+ and HCO3-. Emerging evidence has identified nontraditional roles for ICs, including absorption of filtered Na+ and Cl-, flow-induced K+ secretion (FIKS) and participation in innate immunity. Apical BK channels in ICs are activated by a flow- stimulated increase in intracellular Ca2+ concentration ([Ca2+]i). The rapid initial mechanoinduced increase in [Ca2+]i reflects basolateral Ca2+ entry and release of internal Ca2+ stores. Piezo1, a member of a family of mechanosensitive non-selective cation channels, is expressed along the basolateral membrane of ICs and principal cells (PCs) in the ASDN. In preliminary studies, we found that a Piezo1 inhibitor dampens both the flow- induced [Ca2+]i response in cortical collecting ducts (CCDs) as well as FIKS, whereas an activator increases [Ca2+]i in CCDs perfused at slow flow rates. The flow-induced IC [Ca2+]i response was largely absent in CCDs from mice with an IC-specific genetic deletion of Piezo1. These observations suggest that Piezo1 mediates flow- induced early basolateral Ca2+ entry into ASDN epithelial cells, a key factor in the activation of BK channels. Based on these observations, we hypothesize that Piezo1 channels function as mechanosensors in the ASDN and enable FIKS by facilitating basolateral Ca2+ entry and secondarily activating luminal Ca2+ entry pathways in ICs. Experiments proposed in Aim 1 will define the localization and developmental expression of Piezo1 in the ASDN, and cell type-specific changes in Piezo1 expression in CCDs in response to a low K+ (LK) or high K+ (HK) diet, or aldosterone. Studies in Aim 2 will determine the effects of Piezo1 activators and inhibitors on basal and flow-stimulated [Ca2+]i, effects on net transepithelial Na+ and K+ transport (JNa and JK) in CCDs isolated from control K+ (CK) and HK fed mice, and effects on IC BK channel activity as assessed by patch clamp. Studies proposed in Aim 3 will determine whether targeted deletion of Piezo1 in ICs alters K+ handling in mice, affects flow-induced increases in [Ca2+]i and JNa and JK in microperfused CCDs, and affects IC BK channel activity as assessed by patch clamp. We expect that the results of our proposed studies will uncover novel and unexpected pathways involved in urinary K+ excretion and identify potential targets for novel therapies to treat K+ imbalances.

醛固酮敏感的远端肾单位（ASDN）分泌H+和HCO3-中的插入细胞（ICS）。新兴 证据已经确定了IC的非传统作用，包括吸收过滤的Na+和Cl-流动诱导的K+ 分泌物（FIKS）和参与先天免疫。 IC中的顶端BK通道被流动激活 细胞内Ca2+浓度的刺激增加（[Ca2+] i）。快速初始机械引起的增加 [Ca2+] I反映了基底外侧CA2+进入和内部CA2+存储的释放。 Piezo1，一个家庭的成员 机械敏感的非选择性阳离子通道沿IC的基底外侧膜表达 ASDN中的主要细胞（PC）。在初步研究中，我们发现压电1抑制剂都会抑制流动 - 诱导的[Ca2+] I反应在皮质收集管道（CCD）和FIK中，而激活剂增加 [Ca2+] i在CCD中以缓慢的流速灌注。 CCD中流动诱导的IC [Ca2+] I响应在很大程度上不存在 来自具有压电1的IC特异性遗传缺失的小鼠。这些观察结果表明，压电介导了流动 诱导早期的基底外侧Ca2+进入ASDN上皮细胞，这是BK通道激活的关键因素。 基于这些观察结果，我们假设Piezo1通道在ASDN中充当机械传感器 并通过促进基底外侧CA2+进入，其次激活Luminal Ca2+进入途径 ICS。 AIM 1中提出的实验将定义压电1中的定位和发育表达 响应低K+（LK）或高K+（HK），ASDN和CCD中的电池类型特异性变化 饮食或醛固酮。 AIM 2中的研究将确定压电1活化剂和抑制剂对基底和抑制剂的影响 流量刺激的[Ca2+] i，对从与从与从与从与从与从与从na+和K+转运（JNA和JK）的CCD中分离出的净transepithepithialial Na+和K+转运的影响 控制K+（CK）和HK喂养小鼠，以及对斑块夹评估的IC BK通道活动的影响。研究 在AIM 3中提出的将确定在ICS中有针对性的PIEZO1是否会改变小鼠的K+处理，这会影响 流动诱导的[Ca2+] I和Microperfused CCD中的JNA和JK的增加，并影响IC BK通道活性 通过斑块夹评估。我们希望我们提出的研究的结果将发现新颖而意外的 参与尿液K+排泄的途径，并确定新型疗法治疗K+失衡的潜在靶标。