ARIP1 Deficiency Facilitates the Inhibition of Neuronal Ferroptosis in Cerebral Ischemia by Activin A Through SMAD3 and p38 MAPK Signaling.

INTRODUCTION: Ferroptosis is an essential pathophysiological process in cerebral ischemic injury. Activin receptor-interacting protein 1 (ARIP1) is a negative regulator of the activin signaling pathway in neurons. OBJECTIVE: This study investigated whether activin A inhibits neuronal ferroptosis and the role of ARIP1 in cerebral ischemic injury. METHODS AND RESULTS: In this study, activin A increased the viability of primary neurons under conditions of oxygen-glucose deprivation (OGD). Subsequent RNA-sequencing analysis of activin A-treated neurons identified expression of Slc7a11 as the ferroptosis-associated gene with significant upregulation. Next, using the CRISPR/Cas9 system, mice were generated with a heterozygous deficiency of ARIP1 (Arip1(-/+)), and the results revealed that the expression of GPX4 was markedly elevated and SLC7A11 was reduced in OGD-treated Arip1(-/+) neurons, compared with that in wild-type (WT) neurons, which was accompanied by an increase of p-SMAD3 and a decrease of p-p38 MAPK levels. In addition, our data showed that activin A activated SMAD3 and inhibited p38 MAPK phosphorylation, which differentially modulated SLC7A11 and GPX4 expression, ultimately suppressing OGD-induced ferroptosis. Notably, Arip1(-/+) mice showed an improvement in neurological deficits and reduced cerebral infarction in the permanent middle cerebral artery occlusion (pMCAO) model. Furthermore, we observed that activin A exerted similar protective effects against ischemic injury in Arip1(-/+) mice. CONCLUSION: These findings indicate that downregulating the expression of ARIP1 suppresses neuronal ferroptosis by modulating SLC7A11/GPX4 expression via SMAD3 and p38 MAPK signaling, ultimately enhancing the neuroprotective role of activin A against cerebral ischemia.