Identification and characterization of potent and selective aquaporin-3 and aquaporin-7 inhibitors.

Yonathan Sonntag, Patrizia Gena, Anna Maggio, Tania Singh, Isabella Artner, Michal K Oklinski, Urban Johanson, Per Kjellbom, John Dirk Nieland, Søren Nielsen, Giuseppe Calamita, Michael Rützler

The Journal of biological chemistry 2019 May 03

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The aquaglyceroporins are a subfamily of aquaporins that conduct both water and glycerol. Aquaporin-3 (AQP3) has an important physiological function in renal water reabsorption, and AQP3-mediated hydrogen peroxide (H2O2) permeability can enhance cytokine signaling in several cell types. The related aquaglyceroporin AQP7 is required for dendritic cell chemokine responses and antigen uptake. Selective small-molecule inhibitors are desirable tools for investigating the biological and pathological roles of these and other AQP isoforms. Here, using a calcein fluorescence quenching assay, we screened a library of 7360 drug-like small molecules for inhibition of mouse AQP3 water permeability. Hit confirmation and expansion with commercially available substances identified the ortho-chloride-containing compound DFP00173, which inhibited mouse and human AQP3 with an IC50 of ∼0.1-0.4 μm but had low efficacy toward mouse AQP7 and AQP9. Surprisingly, inhibitor specificity testing revealed that the methylurea-linked compound Z433927330, a partial AQP3 inhibitor (IC50, ∼0.7-0.9 μm), is a potent and efficacious inhibitor of mouse AQP7 water permeability (IC50, ∼0.2 μm). Stopped-flow light scattering measurements confirmed that DFP00173 and Z433927330 inhibit AQP3 glycerol permeability in human erythrocytes. Moreover, DFP00173, Z433927330, and the previously identified AQP9 inhibitor RF03176 blocked aquaglyceroporin H2O2 permeability. Molecular docking to AQP3, AQP7, and AQP9 homology models suggested interactions between these inhibitors and aquaglyceroporins at similar binding sites. DFP00173 and Z433927330 constitute selective and potent AQP3 and AQP7 inhibitors, respectively, and contribute to a set of isoform-specific aquaglyceroporin inhibitors that will facilitate the evaluation of these AQP isoforms as drug targets. © 2019 Sonntag et al.

Citation

Yonathan Sonntag, Patrizia Gena, Anna Maggio, Tania Singh, Isabella Artner, Michal K Oklinski, Urban Johanson, Per Kjellbom, John Dirk Nieland, Søren Nielsen, Giuseppe Calamita, Michael Rützler. Identification and characterization of potent and selective aquaporin-3 and aquaporin-7 inhibitors. The Journal of biological chemistry. 2019 May 03;294(18):7377-7387