TDAG8 activation attenuates cerebral ischaemia-reperfusion injury via Akt signalling in rats
T-cell death-associated gene 8 (TDAG8), a member of the proton-sensitive G-protein-coupled receptor (GPCR) class with an immune-specific expression profile, was recently shown to be expressed in the rat brain; however, its role in ischaemic stroke remains unknown.Methods:
We initially confirmed the time-dependent expression of TDAG8 in rat brain tissue after ischaemic stroke and reperfusion. Further evaluations were performed to increase TDAG8 expression 6 h prior to middle cerebral artery occlusion (MCAO) by injecting a specific agonist, BTB09089, into the lateral ventricle to increase TDAG8 expression. Twenty-four hours before MCAO, a specific small interfering RNA (siRNA) was introduced. The infarction volume, neurological deficit score and cleaved caspase-3 and Bcl-2 expression were used to assess the effects of TDAG8 on ischaemic stroke. Finally, the effects of TDAG8 on the development of primary cortical neurons exposed to oxygen-glucose deprivation (OGD) were investigated.Results:
TDAG8 expression increased both in vivo and in vitro. Pretreatment with BTB09089 up-regulated TDAG8 and Bcl-2 expression and down-regulated cleaved caspase-3 expression, while the infarction volume was reduced, and neurological deficits were ameliorated 24 and 72 h after MCAO. However, the protective effects of TDAG8 were reversed when its level was reduced in TDAG8-deficient rats. More importantly, these findings are consistent with data from neurons subjected to OGD.Conclusions:
TDAG8 plays an important neuroprotective role through inhibition of neuronal apoptosis and alleviation of neurological deficits by activating the Akt signalling pathway in rats.