Periostin protects against alcohol-related liver disease by activating autophagy by interacting with PDI

The matricellular protein periostin plays a critical role in liver inflammation, fibrosis, and even carcinoma. Here, the biological function of periostin in alcohol-related liver disease (ALD) was investigated.We used wild-type (WT), Postn-null (Postn-/-) mice and Postn-/- mice with periostin recovery to investigate the biological function of periostin in ALD. Proximity-dependent biotin identification (BioID) analysis identified the protein that interacted with periostin, and coimmunoprecipitation (Co-IP) analysis validated the interaction between protein disulfide isomerase (PDI) and periostin. Pharmacological intervention and genetic knockdown of PDI were used to investigate the functional correlation between periostin and PDI in ALD development.Periostin was markedly upregulated in the livers of mice that were fed ethanol. Interestingly, periostin deficiency severely aggravated ALD in mice, whereas the recovery of periostin in the livers of Postn-/- mice significantly ameliorated ALD. Mechanistic studies showed that the upregulation of periostin alleviated ALD by activating autophagy through inhibition of the mTORC1 pathway, which was verified in murine models treated with the mTOR inhibitor rapamycin and the autophagy inhibitor MHY1485. Furthermore, a protein interaction map of periostin was generated by BioID analysis. Interaction profile analysis identified PDI as a key protein that interacted with periostin. Intriguingly, periostin-mediated enhancement of autophagy by inhibiting the mTORC1 pathway in ALD depended on its interaction with PDI. Moreover, alcohol-induced periostin overexpression was regulated by transcription factor EB (TFEB).Collectively, these findings clarify a novel biological function and mechanism of periostin in ALD and the periostin-PDI-mTORC1 axis is a critical determinant of ALD.