# High PEEP Activates ITGB1, Inducing Diaphragm Fibrosis During Prolonged Mechanical Ventilation

## TL;DR

High PEEP during mechanical ventilation causes diaphragm fibrosis by activating ITGB1, which could be a target for treating ventilation-induced diaphragm dysfunction.

## Contribution

This study identifies ITGB1 as a novel mediator of PEEP-induced diaphragm fibrosis through TGFβ-1 signaling.

## Key findings

- PEEP increased fibrosis markers TGFβ-1 and α-SMA in the diaphragm.
- ITGB1 knockdown reduced fibrotic protein expression and pathway activation.
- RNA sequencing showed enrichment in fibrosis- and integrin-related pathways.

## Abstract

Background: Mechanical ventilation (MV) with high positive end-expiratory pressure (PEEP) is linked to ventilation-induced diaphragm dysfunction (VIDD), but the role of integrin beta-1 (ITGB1) in PEEP-associated diaphragm fibrosis remains unclear. Methods: Eighteen rabbits were divided into control (CON), MV without PEEP(MV), and MV with 8 cmH2O PEEP (PEEP) groups. C2C12 underwent cyclic stretching (15% tension), and ITGB1 was knocked down. Fibrosis markers (TGFβ-1, α-SMA), ITGB1/ROCK1 expression, and pathway activation were analyzed via RNA sequencing, immunohistochemistry, and Western blotting. Results: The PEEP group exhibited elevated airway pressure and upregulated fibrosis markers (TGFβ-1 and α-SMA) alongside activated ITGB1/ROCK1 mechanotransduction pathways. Stretched C2C12 showed morphological shrinkage and increased fibrotic protein expression. RNA sequencing confirmed enrichment in fibrosis- and integrin-related pathways. ITGB1 knockdown attenuated TGFβ-1 and α-SMA induction. Conclusions: ITGB1 mediates PEEP-induced diaphragm fibrosis via TGFβ-1 signaling and collagen deposition, suggesting ITGB1 targeting as a potential therapeutic strategy for VIDD. These findings elucidate the mechanotransduction mechanisms underlying MV-associated diaphragm dysfunction.