THE ROLE OF PPIA GENE IN LUNG REPAIR DURING MECHANICAL VENTILATION

Mechanical ventilation triggers a complex molecular response that may lead to ineffective lung repair and fibrosis. Our objective is to study the impact of ex-vivo mechanical stretch on repair processes involving epithelial and mesenchymal cells. Bronchoalveolar lavage fluid (BALF) was collected from patients under protective mechanical ventilation (MV, 6-8 ml/kg, PEEP 5 cmH2O) or continuous positive airway pressure (CPAP) of 5 cmH2O, during scheduled cardiac surgery. Wound healing assays were performed on epithelial (BEAS-2B) and fibroblast (MRC5) cells supplemented with these samples. RNA was extracted and sequenced, to identify differences in gene expression, molecular pathways and interactions, related to mechanical stretch. Targeted drug modulation experiments were performed to evaluate the identified molecular mechanisms. An interaction analysis of genes allowed us to exclude pharmacological treatment in MV condition. Cyclic stretch condition resulted in a slower wound closure rate in epithelial cells, compared to the static condition. Fibroblasts exhibited the opposite behavior. Differential expression analysis identified dysregulation in the IL6 and EGFR gene pathways in BEAS-2B, as well as in LIF, IL6, and TGFβ1 in MRC5. The use of tocilizumab reverses the wound closure rates in both cell lines. Interaction RNA analysis highlighted upregulation of PPIA in epithelial cells under cyclic conditions and cellular stretching. Cyclosporine treatment reduced PPIA and IL6 expression. Tidal ventilation promotes a delay in epithelial repair and fibroproliferative response, mediated by IL-6 pathway activation and enhanced TGFβ1 expression. Upstream modulation of stretch-induced expression of PPIA could promote effective tissue regeneration during mechanical ventilation.