CIM0216 is a synthetic TRPM3 activator whose potency and apparent affinity greatly exceeds that of the canonical TRPM3 agonist.

CIM0216 Selectively Activates TRPM3 in Stably Transfected HEK293 Cells.A diverse small-molecule library was screened for compounds that modulate TRPM3-mediated Ca2+ responses in HEK293 cells stably expressing murine TRPM3 (HEK-TRPM3 cells), as described previously[1].In HEK-TRPM3 cells, CIM0216 elicited a dose-dependent Ca2+ response [negative logarithm of the EC50 value (pEC50) = 0.77 ± 0.1 μM], which was not observed in nontransfected HEK293 cells . The endogenous TRPM3 activator pregnenolone sulfate (PS) also elicited a dose-dependent Ca2+ response, typified by a smaller Ca2+ influx and a fivefold lower potency (pEC50 = 3.0 ± 0.1 μM; n = 2) compared with CIM0216 . In the presence of 40 μM PS, the dose dependency of CIM0216 shifted to a lower concentration in HEK-TRPM3 cells (pEC50 = 42 ± 0.6 nM CIM0216 in the presence of PS). Single-cell FURA2-ratiometric Ca2+ imaging revealed a robust increase in intracellular Ca2+ concentration (1,145 ± 26 nM; n = 603 from at least three independent measurements) on stimulation with 1 μM CIM0216 in all HEK-TRPM3 cells. These responses were not observed in nontransfected HEK cells (n = 166) or in the absence of extracellular Ca2+.