Stroke is the most serious and potentially deadly neurological disease and the most important factor leading to permanent disability in adults, significantly affecting the quality of life of stroke patients. The main type of stroke is ischaemic stroke, which is predominately a result of middle cerebral artery occlusion (MCAO). Therefore, there is a need to develop anti-stroke active molecules. However, what’s the pathogenesis of stroke? There is an opinion that T cell death-associated gene 8 (TDAG8, also known as GPR65) regulates ischaemic brain injury by inhibiting the inflammatory response and neuronal apoptosis. Moreover, TDAG8 has been reported to be a proton sensor, that inhibits the production of pro-inflammatory cytokines induced by extracellular acidification. Hence, we will introduce a TDAG8/GPR65 specific agonist-BTB09089.
BTB09089 is a TDAG8/GPR65 specific agonist, which can increase the expression of TDAG8.
In vitro, BTB09089 (1-5 μM; 18 h) suppresses LPS-stimulated TNF-α and IL-6 production and enhances LPS-stimulated IL-10 production in thioglycollate induced peritoneal exude cells (TG-PEC). In addition, BTB09089 (0-18 μM; 30 min) significantly enhances the cAMP accumulation in a dose-dependent manner at pH 7.0-7.9 but not at pH 6.5. Moreover, BTB09089 (1-5 μM; 20 h) suppresses IL-2 production in splenocytes from WT mice in a dose-dependent manner but not from TDAG8 KO mice without affecting the cell viability.
In vivo, BTB09089 (5-20 μM, 8 μL; i.c.v.; 6 hours prior to MCAO) reduces cerebral ischaemia-reperfusion injury in rats. Moreover, BTB09089 up-regulates TDAG8 and Bcl-2 expression and down-regulates cleaved caspase-3 expression. While, the infarction volume is reduced, and neurological deficits are ameliorated 24 and 72 h after middle cerebral artery occlusion (MCAO).
In summary, targeting TDAG8 may lead to novel and promising strategies for attenuating ischaemia-reperfusion injury in stroke patients. And, BTB09089 is a promising agent to anti-stroke as well as attenuates immune-mediated inflammation.
 Ma XD, et al. Exp Neurol. 2017 Jul;293:115-123.
 Onozawa Y, Eur J Pharmacol. 2012 May 15;683(1-3):325-31.