MST4 modulates the neuro-inflammatory response by regulating IκBα signaling pathway and affects the early outcome of experimental ischemic stroke in mice.

MST4 limits peripheral, macrophage-dependent inflammatory responses through direct phosphorylation of the adaptor TRAF6; though its role in neuro-inflammation is unclear. We investigated microglia expression of MST4 and whether is attenuates neuro-inflammatory response after cerebral ischemia-reperfusion injury in mice. Adult male C57BL6 mice were subjected to a 90-minute middle cerebral artery occlusion (MCAO) followed by a 72 -h reperfusing. The results showed that MST4 was involved in the pathological process after cerebral ischemia-reperfusion and was expressed in microglia. MST4-Adeno Associated Virus attenuated brain damage after MCAO and reduced expression of p-IκBα, p-ERK and p-JNK, while MST4 shRNA aggravated brain damage after MCAO and increased expression of p-IκBα, p-ERK and p-JNK. Our results show that MST4 inhibits neuro-inflammatory response in cerebral ischemia-reperfusion injury, improves neurological deficits, and reduces cerebral infarction volume in mice. Strategies to enhance MST4 in response to ischemic stroke may be a potential therapeutic strategy.

The Pathogenesis of Necroptosis-Dependent Signaling Pathway in Cerebral Ischemic Disease.

Necroptosis is the best-described form of regulated necrosis at present, which is widely recognized as a component of caspase-independent cell death mediated by the concerted action of receptor-interacting protein kinase 1 (RIPK1) and receptor-interacting protein kinase 3 (RIPK3). Mixed-lineage kinase domain-like (MLKL) was phosphorylated by RIPK3 at the threonine 357 and serine 358 residues and then formed tetramers and translocated onto the plasma membrane, which destabilizes plasma membrane integrity leading to cell swelling and membrane rupture. Necroptosis is downstream of the tumor necrosis factor (TNF) receptor family, and also interaction with NOD-like receptor pyrin 3 (NLRP3) induced inflammasome activation. Multiple inhibitors of RIPK1 and MLKL have been developed to block the cascade of signal pathways for procedural necrosis and represent potential leads for drug development. In this review, we highlight recent progress in the study of roles for necroptosis in cerebral ischemic disease and discuss how these modifications delicately control necroptosis.