Discovery of Diphenyl Ether Derivatives as Novel BKCa Channel Activators: Structure-Activity Relationship, Cryo-EM Complex Structures, and In Vivo Animal Studies

  • J Med Chem. 2025 Feb 27;68(4):4259-4286. doi: 10.1021/acs.jmedchem.4c02008.
Soo Bin Park  1 ,  Na Young Lee  1 ,  Eun-Young Lee  1 ,  Subin Kim  1 ,  Narasaem Lee  1 ,  Eun Chae Roh  2 ,  Yoon Gyoon Kim  2 ,  Hee Jin Kim  3 ,  Mi Sun Jin  1 ,  Chul-Seung Park  1 ,  Yong-Chul Kim  1
Affiliations
  • 1. School of Life Science, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea.
  • 2. College of Pharmacy, Dankook University, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do 31116, Republic of Korea.
  • 3. Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, 815, Hwarang-ro, Nowon-gu, Seoul 01795, Republic of Korea.
PMID: 39947888 DOI: 10.1021/acs.jmedchem.4c02008
Abstract

The BKCA channel, a large-conductance calcium-activated Potassium Channel, plays a crucial role in maintaining the homeostasis of the micturition cycle and airway-related functions. In this study, we optimized a novel BKCA channel activator, 4d, with a diphenyl ether structure identified from library screening. This led to the discovery of potent activators, 10b (EC50 = 0.12 μM, cell-based assay) and 51b, an orally bioavailable derivative. Compound 10b demonstrated potent in vivo efficacy in a spontaneous hypertensive rat (SHR) of urinary incontinence model, while compound 51b showed dose-dependent cough suppression efficacy with an ED50 of 11.8 mg/kg in a citric acid-induced cough model. Furthermore, we reported the cryo-electron microscopy (cryo-EM) structures of the BKCA channel in complex with 10b and 51b at resolutions of 2.8 and 3.4 Å. Based on structural analyses, we determined the binding sites and key interaction residues of 51b, which were validated via mutation studies.

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