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Discovery of small‐molecule inhibitors of ROMK: one step closer to a potassium‐sparing loop diuretic?
Author(s) -
Denton Jerod,
Lewis L. Michelle,
Banerjee Sreedatta,
Fallen Katherine,
Redha Rey,
Lornsen Katharina A.,
Weaver C. David
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.602.10
Subject(s) - chemistry , potassium channel , nephron , reabsorption , diuretic , pharmacology , small molecule , biophysics , biochemistry , biology , sodium , renal function , organic chemistry
The renal inward rectifying potassium (Kir) channel ROMK plays key roles in regulating systemic electrolyte balance and blood pressure. Because ROMK supports both NaCl reabsorption in the thick ascending limb and potassium secretion in the collecting duct of the nephron, a selective inhibitor of the channel could in principle function as the first potassium‐sparing loop diuretic. At present, however, it is not possible to test this hypothesis due to the lack of suitable channel inhibitors. We therefore developed and implemented a novel fluorescence‐based assay to enable high‐throughput small‐molecule library screening. The assay reports flux of the potassium congener thallium (Tl + ) through ROMK channels using the Tl + ‐sensitive fluorescent dye FluoZin‐2. We show that the assay is robust, DMSO tolerant and enables screening of more than 20,000 compounds per day for ROMK modulators. From a screen of approximately 200,000 small molecules, several new ROMK inhibitors were discovered. We are currently assessing structure‐activity relationships, potency, selectivity and molecular mechanism of action of these compounds.