miR‑195 promotes LPS‑mediated intestinal epithelial cell apoptosis via targeting SIRT1/eIF2a.

A microarray analysis of an animal model with experimental sepsis induced by caecal ligation and puncture revealed that the level of microRNA‑195 (miR‑195) was upregulated. However, to the best of our knowledge, the role of miR‑195 in sepsis remains unknown. The present study investigated the effect of miR‑195 on apoptosis in sepsis and investigated the underlying mechanism. The level of miR‑195 was measured in human intestinal epithelial cells following exposure to lipopolysaccharide (LPS). Cell viability and apoptosis were detected using Cell Counting kit‑8 and flow cytometry assays. The expression levels of apoptosis‑associated proteins were determined using western blot analysis. In addition, a dual‑luciferase reporter assay was employed to verify the association between miR‑195 and sirtuin 1 (SIRT1). Furthermore, the SIRT1 inhibitor EX527 was applied to further confirm the regulatory network of miR‑195/SIRT1 in LPS‑induced apoptosis. It was demonstrated that LPS significantly inhibited cell viability and promoted cell apoptosis in NCM460 cells in a dose‑dependent manner. In addition, miR‑195 was significantly upregulated following LPS treatment. The present results revealed that silencing miR‑195 prevented apoptosis and alleviated cell injury in LPS‑induced NCM460 cells. Further investigation demonstrated that miR‑195 bound directly to and negatively regulated SIRT1. Inhibition of SIRT1 reversed the protective effects of miR‑195‑silencing on the apoptosis and viability of NCM460 cells. Furthermore, silencing miR‑195 prevented endoplasmic reticulum (ER) stress‑induced apoptosis via a downregulation of SIRT1 and its downstream effectors, including activating transcription factor 4, C/EBP homologous protein, glucose‑regulated protein 78 and growth arrest and DNA‑damage protein 34, as well as the phosphorylation of eukaryotic translation initiation factor 2A. In conclusion, the present study revealed a novel mechanism by which miR‑195 regulates SIRT1‑mediated downstream effectors in ER stress‑induced apoptosis in sepsis.

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