# MiRNA-210 is involved in cigarette smoke extract-induced apoptosis of MLE-12 via the Shh signaling pathway

## TL;DR

This study shows that MiRNA-210 helps protect lung cells from cigarette smoke-induced damage by regulating the Shh signaling pathway.

## Contribution

The novel finding is that MiR-210 regulates apoptosis in lung epithelial cells via the Shh signaling pathway in response to cigarette smoke.

## Key findings

- MiR-210 is downregulated in cigarette smoke-exposed lung cells.
- Knockdown of MiR-210 increases apoptosis and emphysema in mice.
- MiR-210 attenuates apoptosis by regulating the Shh signaling pathway.

## Abstract

The aim of the study is the regulatory effect of MicroRNA-210 (MiR-210) on cigarette smoke extract (CSE)-induced mouse lung epithelial type II cells (MLE-12) apoptosis and determine whether the MiR-210 is involved in cigarette smoke extract-induced apoptosis of MLE-12 via Shh signaling pathway.

Expression of MiR-210 in CSE-induced MLE-12 was assessed by qRT-PCR. The emphysema mouse model and MiR-210 knockdown mice were each established by inhaling cigarette smoke or intratracheal lentiviral vector instillation. The Sonic hedgehog (Shh), Ptch1, Gli1, B-cell lymphoma-2 (Bcl-2), and Caspase 3 protein expressions were detected by Western blotting. mRNA expressions of MiR-210, Shh, Ptch1, and Gli1 were measured using quantitative real-time polymerase chain reaction (qRT-PCR). Apoptotic ratios in mice and CSE-induced HPVEC were assessed using TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assays and flow cytometry.

Our results showed that MiR-210 mRNA levels were significantly down-regulated in the CSE-induced MLE 12. MLE 12 apoptosis with down-regulated Shh, Ptch1, Gli1, and Bcl-2 expression, increased Caspase 3 expression in the emphysema mouse model and CSE-induced MLE 12. Knockdown MiR-210 can facilitate cell apoptosis and emphysema via the Shh signaling pathway in mice. In vitro, MiR-210 can attenuate the apoptosis of CSE-exposed MLE 12. Moreover, MiR-210 regulated the Shh pathway and promoted its expression.

MiRNA-210 is involved in cigarette smoke extract-induced apoptosis of MLE-12 via the Shh signaling pathway. The present study reveals that MiRNA-210 may be a key regulator of cellular apoptosis and could be explored as a potential therapeutic target in the future.