Function And Regulation Mechanisms Of Lnc-PCE In Pulmonary Fibrosis

Objective: Pulmonary fibrosis is defined as a specific form of chronic and progressive fibrosing interstitial pneumonia of unknown cause. Because of the unknown pathogenesis, there is no radical cure for it. Epithelial-mesenchymal transition (EMT) generates the abnormal proliferation of myofibroblasts and increased deposits of the extracellular matrix, leading to the lung tissue fibrosis proliferation. Therefore, EMT plays a critical role in the development of pulmonary fibrosis,which indicates that inhibiting EMT may become a potential treatment to alleviate pulmonary fibrosis.Based on the analysis of former study results,it was found that differential expressed long non-coding RNAs (IncRNAs) was confirmed to be closely linked with pulmonary fibrosis. However,IncRNA acts as a competitive endogenous RNA (ceRNA) is till unclear. In this study, IncRNA promotes cell cycle during EMT (lnc-PCE),as a new found IncRNA, its ceRNAmechanism may be considered a promising approach of anti-lung fibrosis therapy.Methods: The animal model was built by intratracheal instillation of bleomycin (BLM). Gene chip technology was used to select the differential expressed lncRNA in rat models and TGF-β1 was performed to establish EMT cell models. Real-time PCR tested lnc-PCE, miR-344a-5p, miR-138-5p,miR-484, miR-370-3p expression both in animal and cell models. Hydroxyproline (HPY) content was tested by colorimetric assays. Gain-and loss-of-function was used to up- or down-regulate lnc-PCE and miR-344a-5p. Immunofluorescence displayed the fluorescence intensity of α-SMA.Western bolt printed out the a-SMA, snail, Cyclin E, Cyclin B, PCNA and MAP3K11 protein levels.PI dyed the DNA of RLE-6TN cells to exam cell cycle. Real time cellular analysis (RTCA) tested RLE-6TN cells proliferation. Dual luciferase reporter assay confirmed the targeted relationship among lnc-PCE, miR-344a-5p and MAP3K11.Results: Lnc-PCE was up-regulated in rat pulmonary fibrosis models through gene chip sifting and has a positive correlation with HYP content. MiR-344a-5p was down-regulated, while miR-138-5p, miR-484, miR-370-3p were up-regulated. Lnc-PCE siRNA inhibited cell cycle during EMT process and caused relevant mark protein (a-SMA, snail, PCNA and cyclin E) decreased.Moreover, there was a complementation between lnc-PCE 3’ UTR sequence GAGCCUG and miR-344a-5p seed sequence CUCGGAC, MAP3K11 3’UTR sequence GAGCCUG and miR-344a-5p seed sequence CUCGGAC. Over-expression of miR-344a-5p leaded to the reduction of lnc-PCE and MAP3K11, restraining the pro-fibrogenic effect that caused by lnc-PCE. Silencing miR-344a-5p increased lnc-PCE and MAP3K11, accelerating EMT.Conclusion: Lnc-PCE competitively combines with MAP3K11 for miR-344a-5p to protect this pro-fibrogenic gene, inducing the acceleration of cell cycle process during EMT...