Fig. 2
SI113 blocks TRPV4-mediated transepithelial ion flux and conductance changes in a human choroid plexus cell line (HIBCPP). Short circuit current, ISC, is a measure of net transepithelial electrogenic ion flux; conductance, the inverse of the transepithelial electrical resistance, is a measurement of the transepithelial permeability. HIBCPP confluent monolayers were mounted in Ussing chambers and allowed to reach stable baselines. At time t = − 5 min, experimental cultures were incubated with 25 µM SI113 bilaterally and at time t = 0 min, all cultures received 10 nM GSK apically to stimulate transepithelial ion transport. Pretreatment with SI 113 (pink trace) substantially inhibited TRPV4-mediated changes in transepithelial ion flux A and completely inhibited the TRPV4-mediated increase in conductance B (black trace = control). Post-treatment with SI 113 added at time t = 5 min (teal trace), reversed the ongoing TRPV4-mediated transport and conductance. C Fluid produced in microliters per square centimeter by cultures treated with DMSO (control), GSK (15 nM) or SI + GSK (25 μM SI113) for 15 min. n = 5 DMSO and n = 7 GSK data points replicated from Hulme et al. [22]. Data represented as mean ± sem in all graphs. n = number of replicates; ns = not significant; GSK = GSK1016790A, TRPV4 agonist. HIBCPP = human choroid plexus papilloma cell line