Caspofungin suppresses brain cell necroptosis in the ischemic stroke rat via up-regulation of Pellino3

Abstract Purpose Pellino3, an ubiquitin E3 ligase, prevents the formation of the death-induced signaling complex in response to TNF-α via targeting receptor-interacting protein kinase 1 (RIPK1), and bioinformatics analysis predicts the interaction between Pellino3 and caspofungin, a common antifungal drug used in clinic. This study aims to explore the effect of caspofungin on brain injury in ischemic stroke and the underlying mechanisms. Methods The SD rat brains (or nerve cells) were subjected to 2h-ischemia (or 8h-hypoxia) plus 24h-reperfusion (or 24h-reoxygenation) to establish the I/R (or H/R) injury model. The cerebral injury was assessed by the methods of triphenyltetrazolium chloride (TTC) staining and Hematoxylin & eosin (H&E) staining. The correlations among caspofungin, Pellino3 and necroptosis in I/R-treated brain or H/R-treated nerve cells were evaluated by biochemistry, molecular and gene overexpression assays. Results The I/R-treated brain showed the injuries (increase in neurological deficit score and infarct volume), downregulation of Pellino3, decreased ubiquitination of RIPK1 and up-regulation of necroptosis-associated proteins [RIPK1, RIPK3, mixed lineage kinase domain-like protein (MLKL), p-RIPK1, p-RIPK3 and p-MLKL]. Caspofungin treatment improved neurological function, reduced infarct volume, up-regulated Pellino3, increased RIPK1 ubiquitination and down-regulated levels of RIPK1, p-RIPK1, p-RIPK3 and p-MLKL. In PC12 cells, H/R treatment caused cellular injury (LDH release and necroptosis), downregulation of Pellino3, decreased ubiquitination of RIPK1 and up-regulation of necroptosis-associated proteins, these phenomena were reversed by overexpression of Pellino3. Conclusion Pellino3 has an important role in counteracting necroptosis via ubiquitination of RIPK1 and caspofungin can suppress the brain cell necroptosis in ischemic stroke via upregulation of Pellino3.