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.
Rocio K Finol-Urdaneta  1  2 ,  Jeffrey R McArthur  2 ,  Ashraf Aboelela  3  4 ,  Richard S Bujaroski  3  5 ,  Hiwa Majed  3 ,  Alejandra Rangel  2 ,  David J Adams  2 ,  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.
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