Sphingosine-1-phosphate receptor 3 promotes neuronal apoptosis via the TNF-α/caspase-3 signaling pathway after acute intracerebral hemorrhage

Background: Intracerebral hemorrhage (ICH) has a high incidence and mortality rate among cerebrovascular diseases, and effective treatments are lacking. Sphingosine-1-phosphate receptor 3 (S1PR3) is associated with secondary immune inflammatory injury following ICH. However, its relationship with neuronal apoptosis and the specific underlying mechanism are not clear. Methods: We observed the effect of S1PR3 on neuronal apoptosis by assessing neurobehavioral scores, performing Western blot (WB) analysis, and performing TUNEL staining in a mouse model of ICH. Moreover, WBs and flow cytometry were used to study the specific mechanism and signaling pathways in HT22 cells in vitro. Results: The expression of S1PR3, CCL2, TNF-alpha, and cleaved-caspase-3 (c-caspase-3) and neuronal apoptosis were significantly increased after ICH, accompanied by neurobehavioral deterioration. These effects were significantly improved by treatment with CAY10444, a specific S1PR3 antagonist. After S1P stimulation of HT22 cells, the expression of S1PR3, CCL2, TNF-alpha and c-caspase-3 increased, and neuronal apoptosis increased by activating caspase-3 through the downstream PI3K/AKT apoptosis signaling pathway. After CAY10444 treatment, the expression of CCL2, TNF-alpha and c-caspase-3 was significantly reduced, and the PI3K/AKT apoptotic signaling pathway was regulated to reduce neuronal apoptosis. Conclusion: An increase in S1P/S1PR3 after ICH may induce neuronal apoptosis by increasing TNF-alpha expression and activating the PI3K/AKT signaling pathway and the expression of caspase-3 effector proteins. CAY10444 can reduce neuronal apoptosis, improve symptoms and play a neuroprotective role by antagonizing S1PR3. S1PR3 may be a promising therapeutic target.