K2P2.1 (TREK-1) potassium channel activation protects against hyperoxia-induced lung injury

Tatiana Zyrianova,Sriharsha Talapaneni,Leanne Wong,Riccardo Olcese,Benjamin Lopez,Victoria Nguyen,John Belperio,Christopher M Waters,Andreas Schwingshackl

doi:10.1038/s41598-020-78886-y

Tatiana Zyrianova, Sriharsha Talapaneni + Show 7 more

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https://doi.org/10.1038/s41598-020-78886-y

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Abstract

No targeted therapies exist to counteract Hyperoxia (HO)-induced Acute Lung Injury (HALI). We previously found that HO downregulates alveolar K2P2.1 (TREK-1) K+ channels, which results in worsening lung injury. This decrease in TREK-1 levels leaves a subset of channels amendable to pharmacological intervention. Therefore, we hypothesized that TREK-1 activation protects against HALI. We treated HO-exposed mice and primary alveolar epithelial cells (AECs) with the novel TREK-1 activators ML335 and BL1249, and quantified physiological, histological, and biochemical lung injury markers. We determined the effects of these drugs on epithelial TREK-1 currents, plasma membrane potential (Em), and intracellular Ca2+ (iCa) concentrations using fluorometric assays, and blocked voltage-gated Ca2+ channels (CaV) as a downstream mechanism of cytokine secretion. Once-daily, intra-tracheal injections of HO-exposed mice with ML335 or BL1249 improved lung compliance, histological lung injury scores, broncho-alveolar lavage protein levels and cell counts, and IL-6 and IP-10 concentrations. TREK-1 activation also decreased IL-6, IP-10, and CCL-2 secretion from primary AECs. Mechanistically, ML335 and BL1249 induced TREK-1 currents in AECs, counteracted HO-induced cell depolarization, and lowered iCa2+ concentrations. In addition, CCL-2 secretion was decreased after L-type CaV inhibition. Therefore, Em stabilization with TREK-1 activators may represent a novel approach to counteract HALI.

Highlights

No targeted therapies exist to counteract Hyperoxia (HO)-induced Acute Lung Injury (HALI)
Histological analysis (Fig. 1A) and blinded Lung Injury Scoring (LIS; Fig. 1B) of H&E-stained mouse lung sections revealed that under room air (RA) conditions administration of ML335 and BL1249 had no damaging effect on lung histology
In this study we propose activation of that HO downregulates alveolar K2P2.1 (TREK-1) K+ channels as a potentially new therapeutic approach against HO‐induced acute lung injury (HALI), since currently no targeted interventions exist that translate into improved patient outcomes

Summary

Introduction

No targeted therapies exist to counteract Hyperoxia (HO)-induced Acute Lung Injury (HALI). We previously found that HO downregulates alveolar K2P2.1 (TREK-1) K+ channels, which results in worsening lung injury This decrease in TREK-1 levels leaves a subset of channels amendable to pharmacological intervention. We treated HO-exposed mice and primary alveolar epithelial cells (AECs) with the novel TREK-1 activators ML335 and BL1249, and quantified physiological, histological, and biochemical lung injury markers. A similar dose- and time-dependent inflammatory response to HO can be reproduced in animal models of H ALI14–16, demonstrating close similarities in lung injury phenotypes between animals and h umans[15,17,18,19,20] From these studies we learned that the molecular mechanisms underlying HALI are complex and include extensive alterations in inflammatory cytokine gmail.com. Minimizing HO exposure is complicated by the lack of consensus in defining the lower limits of permissive hypoxemia, which would allow us to clinically differentiate beneficial from injurious levels of HO t herapy[27,28]

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