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-α, 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-α 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-α 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-α 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.