Unveiling some FDA-approved drugs as inhibitors of the store-operated Ca2+ entry pathway
SCIENTIFIC REPORTS
Authors: Rahman, Saifur; Rahman, Taufiq
Abstract
The store-operated calcium entry (SOCE) pathway is an important route for generating cytosolic Ca2+ signals that regulate a diverse array of biological processes. Abnormal SOCE seem to underlie several diseases that notably include allergy, inflammation and cancer. Therefore, any modulator of this pathway is likely to have significant impact in cell biology under both normal and abnormal conditions. In this study, we screened the FDA-approved drug library for agents that share significant similarity in 3D shape and surface electrostatics with few, hitherto best known inhibitors of SOCE. This has led to the identification of five drugs that showed dose-dependent inhibition of SOCE in cell-based assay, probably through interacting with the Orai1 protein which effectively mediates SOCE. Of these drugs, leflunomide and teriflunomide could suppress SOCE significantly at clinically-relevant doses and this provides for an additional mechanism towards the therapeutic utility of these drugs as immunosuppressants. The other three drugs namely lansoprazole, tolvaptan and roflumilast, were less potent in suppressing SOCE but were more selective and thus they may serve as novel scaffolds for future development of new, more efficacious SOCE inhibitors.
Urocortin-2 Prevents Dysregulation of Ca2+ Homeostasis and Improves Early Cardiac Remodeling After Ischemia and Reperfusion
FRONTIERS IN PHYSIOLOGY
Authors: Dominguez-Rodriguez, Alejandro; Mayoral-Gonzalez, Isabel; Avila-Medina, Javier; de Rojas-de Pedro, Eva S.; Calderon-Sanchez, Eva; Diaz, Ignacio; Hmadcha, Abdelkrim; Castellano, Antonio; Rosado, Juan A.; Benitah, Jean-Pierre; Gomez, Ana M.; Ordonez, Antonio; Smani, Tarik
Abstract
Aims: Urocortin-2 (Ucn-2) is a potent cardioprotector against Ischemia and Reperfusion (I/R) injuries. However, little is known about its role in the regulation of intracellular Ca2+ concentration ([Ca2+](i)) under I/R. Here, we examined whether the addition of Ucn-2 in reperfusion promotes cardioprotection focusing on {[Ca2+](i) handling. Methods and Results: Cardiac Wistar rat model of I/R was induced by transient ligation of the left coronary artery and experiments were conducted 1 week after surgery in tissue and adult cardiomyocytes isolated from risk and remote zones. We observed that I/R promoted significant alteration in cardiac contractility as well as an increase in hypertrophy and fibrosis in both zones. The study of confocal [Ca2+](i) imaging in adult cardiomyocytes revealed that I/R decreased the amplitude of [Ca2+](i) transient and cardiomyocytes contraction in risk and remote zones. Interestingly, intravenous infusion of Ucn-2 before heart's reperfusion recovered significantly cardiac contractility and prevented fibrosis, but it didn't affect cardiac hypertrophy. Moreover, Ucn-2 recovered the amplitude of [Ca2+](i) transient and modulated the expression of several proteins related to [Ca2+](i) homeostasis, such as TRPC5 and Orai1 channels. Using Neonatal Rat Ventricular Myocytes (NRVM) we demonstrated that Ucn-2 blunted I/R-induced Store Operated Ca2+ Entry (SOCE), decreased the expression of TRPC5 and Orai1 as well as their interaction in reperfusion. Conclusion: Our study provides the first evidences demonstrating that Ucn-2 addition at the onset of reperfusion attenuates I/R-induced adverse cardiac remodeling, involving the [Ca2+](i) handling and inhibiting the expression and interaction between TRPC5 and Orai1.