Elucidating novel mechanism of action of spiperone for drug repurposing to prevent and treat murine colitis and sepsis.

AIMS: While Ca2+ signaling plays a vital role in maintaining normal endothelial function and vascular activity, aberrant Ca2+ signaling in endothelial dysfunction is involved in the pathogenesis of inflammation. As a safe anti-psychotic drug to mobilize Ca2+ signaling, we repurposed spiperone as a potential drug for two intestinal epithelial injury related diseases, colitis and sepsis.

MATERIALS AND METHODS: Spiperone-induced vasorelaxation of human submucosal arterioles and mesenteric arterioles from wide-type and TRPV4 KO mice was determined by Mulvany-style wire myograph. The action of spiperone in HUVEC was tested by Ca2+ imaging and patch clamp, and its action on murine mesenteric arterioles was measured in vivo. LPS- and CLP-induced septic mice and DSS-induced colitic mice were used to examine the anti-inflammatory effects of spiperone.

KEY FINDINGS: Spiperone induced endothelium-dependent hyperpolarization (EDH)-mediated vasorelaxation of healthy arterioles with EC50 of ∼50 nM predominately via PLC/IP3/IP3R pathway to induce endoplasmic reticulum (ER) Ca2+ release and further to promote Ca2+ entry via TRPV4-constituted SOCE. In both LPS- and CLP-induced septic mice, spiperone effectively prevented and treated sepsis by reducing serum proinflammatory factors, alleviating multiple organ dysfunction, rescuing the impaired EDH-mediated vasorelaxation and improving murine survival rate. Similarly, spiperone could also protect against murine colitis.

SIGNIFICANCE: We reveal new action mode and mechanism of spiperone to induce EDH-mediated vasorelaxation of both human and murine arterioles to protect against colitis and sepsis by innovatively inducing PLC/IP3R/Ca2+ signaling rather than canonically antagonizing GPCR. Spiperone could be repurposed as a potential new drug for the prevention/treatment of colitis and sepsis.