Pathophysiological and Pharmacological Characteristics of KCNJ5 157-159delITE Somatic Mutation in Aldosterone-Producing Adenomas.

Kang-Yung Peng,Jeff S Chueh,Peng-Ying Chen,Chien-Yuan Pan,Yen-Hung Lin,Vin-Cent Wu,Hung-Wei Liao,Yung-Ming Chen,Chun-Lin Huang

doi:10.3390/biomedicines9081026

Kang-Yung Peng, Jeff S Chueh + Show 7 more

Open Access

https://doi.org/10.3390/biomedicines9081026

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Abstract

Mutated channelopathy could play important roles in the pathogenesis of aldosterone-producing adenoma (APA). In this study, we identified a somatic mutation, KCNJ5 157-159delITE, and reported its immunohistological, pathophysiological and pharmacological characteristics. We conducted patch-clamp experiments on HEK293T cells and experiments on expression of aldosterone synthase (CYP11B2) and aldosterone secretion in HAC15 cells to evaluate electrophysiological and functional properties of this mutated KCNJ5. Immunohistochemistry was conducted to identify expressions of several steroidogenic enzymes. Macrolide antibiotics and a calcium channel blocker were administrated to evaluate the functional attenuation of mutated KCNJ5 channel in transfected HAC15 cells. The interaction between macrolides and KCNJ5 protein was evaluated via molecular docking and molecular dynamics simulation analysis. The immunohistochemistry analysis showed strong CYP11B2 immunoreactivity in the APA harboring KCNJ5 157-159delITE mutation. Whole-cell patch-clamp data revealed that mutated KCNJ5 157-159delITE channel exhibited loss of potassium ion selectivity. The mutant-transfected HAC15 cells increased the expression of CYP11B2 and aldosterone secretion, which was partially suppressed by clarithromycin and nifedipine but not roxithromycin treatment. The docking analysis and molecular dynamics simulation disclosed that roxithromycin had strong interaction with KCNJ5 L168R mutant channel but not with this KCNJ5 157-159delITE mutant channel. We showed comprehensive evaluations of the KCNJ5 157-159delITE mutation which revealed that it disrupted potassium channel selectivity and aggravated autonomous aldosterone production. We further demonstrated that macrolide antibiotics, roxithromycin, could not interfere the aberrant electrophysiological properties and gain-of-function aldosterone secretion induced by KCNJ5 157-159delITE mutation.

Highlights

Primary aldosteronism (PA) is the most common form of secondary hypertension, characterized by elevated plasma aldosterone and low renin hypertension, and affects~10% of hypertensive patients [1,2]
Other ion channel mutations have been reported to involve in the pathogenesis of aldosteroneproducing adenoma (APA) including loss-of-function mutations of ATP1A1 and ATP2B3 genes, and gain-of-function mutation of CACNA1D gene, which are present in 1 to 8% of APAs [8,9,10]
We identified a KCNJ5 157-159delITE mutation, which is located near the selectivity filter of the potassium channel and functionally similar to the previously reported G151R and L168R substitution mutations

Summary

Introduction

Primary aldosteronism (PA) is the most common form of secondary hypertension, characterized by elevated plasma aldosterone and low renin hypertension, and affects~10% of hypertensive patients [1,2]. Primary aldosteronism (PA) is the most common form of secondary hypertension, characterized by elevated plasma aldosterone and low renin hypertension, and affects. Biomedicines 2021, 9, 1026 studies indicate that somatic mutations of the potassium channel KCNJ5 gene could be identified in 34 to 73% of APAs [4,5,6,7]. It has been clearly demonstrated that KCNJ5 mutations result in loss of channel selectivity leading to membrane depolarization. KCNJ5 G151R and L168R are the most common somatic mutations in sporadic APAs in previous studies [4,12]. These two KCNJ5 mutations are located in or near the selectivity filter in the glycine–tyrosine–

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