BML‐241 fails to display selective antagonism at the sphingosine‐1‐phosphate receptor, S1P₃

Abstract

Background and purpose: The thiazolidine carboxylic acid, BML-241, has been proposed as a lead compound in development of selective antagonists at the sphingosine-1-phosphate receptor (S1P 3 ), based on its inhibition of the rise in intracellular calcium concentrations ([Ca 2 þ ] i ) in HeLa cells overexpressing S1P receptors. We have studied the antagonistic properties of BML-241 for the S1P 3 receptor in more detail. Experimental approach: Chinese hamster ovary (CHO) cells stably transfected with the S1P 3 , S1P 2 or a 1A -adrenoceptors were used to investigate the effect of BML-241 on increases in [Ca 2 þ ] i mediated via different receptors. CHO-K1 cells were used to study ATP-induced [Ca 2 þ ] i elevations. Effects on S1P 3 -mediated inhibition of forskolin-induced cAMP accumulation and on binding to a 1A -adrenoceptors were also investigated. In addition, the effect of BML-241 on contractions of rat mesenteric artery induced by phenylephrine was studied in an organ bath. Key results: High concentrations of BML-241 (10 mM) inhibited the rise in [Ca 2 þ ] i induced by S1P 3 and S1P 2 receptor stimulation; lower concentrations were ineffective. This high concentration of BML-241 also inhibited [Ca 2 þ ] i increases via P2 (nucleotide) receptor or a 1A -adrenoceptor stimulation. Moreover, BML-241 (10 mM) inhibited a 1 -adrenoceptor-mediated contraction of rat mesenteric artery but did not displace [3 H]-prazosin from a 1A -adrenoceptors in concentrations up to 100 mM. BML-241 (10 mM) did not affect the S1P 3 -mediated decrease of forskolin-induced cAMP accumulation. Conclusions and Implications: We conclude that BML-241 is a low potency, non-selective inhibitor of increases in [Ca 2 þ ] i , rather than a specific antagonist at the S1P 3 receptor.

FTY720 Normalizes Hyperglycemia by Stimulating β-Cell in Vivo Regeneration in db/db Mice through Regulation of Cyclin D3 and p57KIP2

“…Consistent with the findings in vivo and ex vivo, FTY720 or FTY720-P treatment significantly increased cyclin D3 expression in INS-1 cells, which was reversed significantly by CAY10444 (also known as BML-241), a selective antagonist of S1P 3 (43), or by W123, a selective antagonist of S1P 1 (44) (Fig. 9C).…”

Sphingosine-1-Phosphate-Induced Airway Hyper-Reactivity in Rodents Is Mediated by the Sphingosine-1-Phosphate Type 3 Receptor

“…Nonetheless, this conclusion has to be challenged by the fact that it was based on the ineffectiveness of suramin and 2-undecyl-thiazolidine-4-carboxylic acid (BML-241) to inhibit the S1P-driven increase in sensitivity to acetylcholine. However, suramin is a nonselective anionic polycyclic dye that blocks many receptor/ligand interactions, and BML-241 has been shown not to be a S1P 3 antagonist but rather a nonselective inhibitor of increases in intracellular calcium (Jongsma et al, 2006). In contrast, our data showing that FTY720-P-induced hyper-reactivity to 5-HT is abrogated in tracheal segments isolated from S1P 3 receptor-deficient mouse provides powerful evidence that this phenomenon is mediated by the S1P 3 receptor in this species.…”

Sphingosine-1-Phosphate Modulates Vascular Permeability and Cell Recruitment in Acute Inflammation In Vivo

“…Mice were divided into five groups (n ϭ 6) and received intraperitoneal administration of 1) L-cycl, an inhibitor of sphingolipid metabolism (30 mg/kg in 200 l) 24 h and 30 min before the beginning of inflammation, 2) DTD, an inhibitor of both isoforms of SPKs (1 mg/kg in 200 l) 30 min before inflammogen application, 3) an S1P 3 antagonist (BML-241; 0.3-3 mg/kg in 200 l intraperitoneally) 30 min before inflammogen application, 4) an S1P 2 antagonist (JTE-013; 0.3-3 mg/kg in 200 l intraperitoneally) 30 min before inflammogen application (Koide et al, 2002;Jongsma et al, 2006;Chiba et al, 2010;Imasawa et al, 2010), or 5) vehicle (DMSO/saline 0.1%). Mice were then lightly anesthetized with enflurane.…”