Genetik und Physiologie von Kalium-Kanälen in der renalen Elektrolyt- und Blutdruckregulation

钾离子通道在人体电解质和血压稳态中起着关键作用。我们最近描述了一种新的人类综合征，结合早发性癫痫发作，感音神经性耳聋，共济失调，精神发育迟滞和电解质失衡（SEEROID），并确定KCNJ 10为致病基因。KCNJ 10编码Kir4.1内向整流钾通道，在脑、内耳和肾中表达。在这个项目的第一部分，我计划通过评估致病突变对通道表达，运输和功能的影响，在分子水平上研究塞氏综合征的病理生理学。然后将使用日益复杂的模型（非洲爪蟾卵母细胞、肾细胞系、已建立的敲除小鼠模型）来检查Kir4.1在肾电解质稳态中的作用。我们假设Kir4.1对于远端肾单位中Na+- K+-ATP酶的K+基底外侧再循环是必要的，提出了上游调节剂的问题;调节肾盐重吸收和钾分泌的肾素血管紧张素醛固酮系统和WNK（无赖氨酸= K）激酶是这种途径的极好候选者。在这个计划的第二部分，我将研究肾上腺双孔背景钾通道在原发性醛固酮增多症（人类高血压的一种形式）中的作用。

Potassium channels play a key role in human electrolyte and blood pressure homeostasis. We have recently described a novel human syndrome, combining early onset Seizures, Sensorineural deafness, Ataxia, Mental retardation and Electrolyte imbalance (SeSAME), and identified KCNJ10 as the causative gene. KCNJ10 encodes the Kir4.1 inward rectifier K+ channel expressed in brain, inner ear and kidney. In the first part of this project, I plan to study the pathophysiology of SeSAME syndrome on a molecular level by assessing the impact of disease causing mutations on channel expression, trafficking and function. Models of increasing complexity (Xenopus oocytes, a renal cell line, an established knockout mouse model) will then be used to examine the role of Kir4.1 in renal electrolyte homeostasis. We hypothesize that Kir4.1 is necessary for basolateral recycling of K+ for the Na+- K+-ATPase in the distal nephron, raising the question of upstream regulators; the renin angiotensin aldosterone system and the WNK (with no lysine = K) kinases regulating renal salt reabsorption and potassium secretion are excellent candidates for such a pathway. In the second part of this proposal, I will study the role of adrenal two-pore background potassium channels in primary aldosteronism, a form of human hypertension.