Automated Patch Clamp Screening of Amiloride and 5- N, N-Hexamethyleneamiloride Analogs Identifies 6-Iodoamiloride as a Potent Acid-Sensing Ion Channel Inhibitor

Rocio K Finol-Urdaneta; Jeffrey R McArthur; Ashraf Aboelela; Richard S Bujaroski; Hiwa Majed; Alejandra Rangel; David J Adams; Marie Ranson; Michael J Kelso; Benjamin J Buckley

doi:10.1021/acs.molpharmaceut.2c01083

Automated Patch Clamp Screening of Amiloride and 5- N, N-Hexamethyleneamiloride Analogs Identifies 6-Iodoamiloride as a Potent Acid-Sensing Ion Channel Inhibitor

Mol Pharm. 2023 Jul 3;20(7):3367-3379. doi: 10.1021/acs.molpharmaceut.2c01083. Epub 2023 Jun 1.

Authors

Rocio K Finol-Urdaneta^{1

2}, Jeffrey R McArthur², Ashraf Aboelela^{3

4}, Richard S Bujaroski^{3

5}, Hiwa Majed³, Alejandra Rangel², David J Adams², Marie Ranson^{2

3}, Michael J Kelso^{2

3}, Benjamin J Buckley^{2

3}

Affiliations

¹ Electrophysiology Facility for Cell Phenotyping and Drug Discovery, Wollongong, New South Wales 2522, Australia.
² Illawarra Health and Medical Research Institute (IHMRI), Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, New South Wales 2522, Australia.
³ School of Chemistry and Molecular Bioscience and Molecular Horizons Institute, University of Wollongong, Wollongong, New South Wales 2522, Australia.
⁴ Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Sphinx University, Assiut 71515, Egypt.
⁵ Monash Institute of Pharmaceutical Sciences, Australian Translational Medicinal Chemistry Facility (ATMCF), Monash University, Parkville, Victoria 3052, Australia.

PMID: 37260417
DOI: 10.1021/acs.molpharmaceut.2c01083

Abstract

Acid-sensing ion channels (ASICs) are transmembrane sensors of extracellular acidosis and potential drug targets in several disease indications, including neuropathic pain and cancer metastasis. The K⁺-sparing diuretic amiloride is a moderate nonspecific inhibitor of ASICs and has been widely used as a probe for elucidating ASIC function. In this work, we screened a library of 6-substituted and 5,6-disubstituted amiloride analogs using a custom-developed automated patch clamp protocol and identified 6-iodoamiloride as a potent ASIC1 inhibitor. Follow-up IC₅₀ determinations in tsA-201 cells confirmed higher ASIC1 inhibitory potency for 6-iodoamiloride 94 (hASIC1 94 IC₅₀ = 88 nM, cf. amiloride 11 IC₅₀ = 1.7 μM). A similar improvement in activity was observed in ASIC3-mediated currents from rat dorsal root ganglion neurons (rDRG single-concentration 94 IC₅₀ = 230 nM, cf. 11 IC₅₀ = 2.7 μM). 6-Iodoamiloride represents the amiloride analog of choice for studying the effects of ASIC inhibition on cell physiology.

Keywords: 6-iodoamiloride; ASIC; ASIC inhibition; acid-sensing ion channel; amiloride; small molecule; synchropatch.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acid Sensing Ion Channels* / pharmacology
Acid Sensing Ion Channels* / physiology
Amiloride* / pharmacology
Animals
Neurons
Rats

Substances

Acid Sensing Ion Channels
6-iodoamiloride
5-(N,N-hexamethylene)amiloride
Amiloride