Long Noncoding RNA MIATNB Regulates Hyperosmotic Stress-induced Corneal Epithelial Cell Injury by Inhibiting...

Dry eye disease (DED) has a complex etiology and the roles of long noncoding RNAs (lncRNAs) in its pathophysiology are not completely understood. Autophagy is a self-eating process important for cell survival and homeostasis. The present study explored the role of myocardial infarction-associated transcript neighbor (MIATNB) long non-coding RNA in hyperosmolarity-induced autophagy and apoptosis in human corneal epithelial cell (HCEC)-based model of dry eye disease.

In vitro assays were performed with a human SV40 immortalized corneal epithelial cell line. Different concentrations of NaCl were used to create hyperosmolarity. HCECs were cultured in presence of 70-120 mM NaCl for 24 h to create an in vitro model of dry eye. RT-qPCR was performed to assess the expression of dry eye related LC3B, ATG16L, BECN1, ATG1, ATG7, ATG13, ATG5, ATG10, and ATG101 mRNAs and western blot analysis of LC3B and P62 and RFP -GFP-tagged LC3. Flow cytometry and western blot analysis of caspase 3, BCL2 and BAX were performed to detect apoptosis. Chloroquine (CQ) was used to inhibit autophagy pharmacologically.

Autophagy flux was activated in HCECs subjected to hyperosmotic stress. Hyperosmolarity activated apoptosis and inhibited HCEC migration and autophagy. Hyperosmolarity upregulated MIATNB expression, while MIATNB knockdown inhibited autophagosome degradation and promoted HCEC apoptosis. Under hyperosmolar conditions, MIATNB knockdown also inhibited the degradation of autophagolysosomes and stimulated HCEC apoptosis.

MIATNB plays a vital role in dry eye pathogenesis and serves as a bridge between autophagy and apoptosis. Targeting MIATNB for DED treatment should be further evaluated.