A G protein-biased S1P1 agonist, SAR247799, protects endothelial cells without affecting lymphocyte numbers

Endothelial dysfunction is a hallmark of tissue injury and is believed to initiate the development of vascular diseases. Sphingosine-1 phosphate receptor-1 (S1P1) plays fundamental physiological roles in endothelial function and lymphocyte homing. Currently available clinical molecules that target this receptor are desensitizing and are essentially S1P1 functional antagonists that cause lymphopenia. They are clinically beneficial in autoimmune diseases such as multiple sclerosis. In patients, several side effects of S1P1 desensitization have been attributed to endothelial damage, suggesting that drugs with the opposite effect, namely, the ability to activate S1P1, could help to restore endothelial homeostasis. We found and characterized a biased agonist of S1P1, SAR247799, which preferentially activated downstream G protein signaling to a greater extent than β-arrestin and internalization signaling pathways. SAR247799 activated S1P1 on endothelium without causing receptor desensitization and potently activated protection pathways in human endothelial cells. In a pig model of coronary endothelial damage, SAR247799 improved the microvascular hyperemic response without reducing lymphocyte numbers. Similarly, in a rat model of renal ischemia/reperfusion injury, SAR247799 preserved renal structure and function at doses that did not induce S1P1-desensitizing effects, such as lymphopenia and lung vascular leakage. In contrast, a clinically used S1P1 functional antagonist, sipon...

Source: Signal Transduction Knowledge Environment - June 1, 2020 Category: Science Authors: Poirier, B., Briand, V., Kadereit, D., Schäfer, M., Wohlfart, P., Philippo, M.-C., Caillaud, D., Gouraud, L., Grailhe, P., Bidouard, J.-P., Trellu, M., Muslin, A. J., Janiak, P., Parkar, A. A. Tags: STKE Research Articles Source Type: news