Long Non-coding RNAs In Animal Models Of Ventilator-induced Lung Injury Suggest Their Potential Inflammatory Effects

Part one Expression profiling analysis of long noncoding RNAs in a mouse model of ventilator-induced lung injury indicating potential roles in inflammationObjective:The key regulators of inflammation underlying ventilator-induced lung injury(VILI)remain poorly defined.Long noncoding RNAs(IncRNAs)have been implicated in the inflammatory response of many diseases;however,their roles in VILI remain unclear.We,therefore,performed transcriptome profiling of IncRNAs and messenger RNA(mRNAs)using RNA sequencing in lungs collected from mice model of VILI and control groups.Methods:Gene expression was analyzed through RNA sequencing and quantitative reverse transcription polymerase chain reaction.A comprehensive bioinformatics analysis was used to characterize the expression profiles and relevant biological functions and for multiple comparisons among the controls and the injury models at different time points.Finally,IncRNAs-mRNAs coexpression networks were constructed and dysregulated IncRNAs were analyzed functionally.Results:The mRNAs transcript profiling,coexpression network analysis,and functional analysis of altered IncRNAs indicated enrichment in the regulation of immune system/inflammation processes,response to stress,and inflammatory pathways.We identified the IncRNA Gm43181 might be related to lung damage and neutrophil activation via chemokine receptor chemokine(C-X-C)recetor 2.Conclusions:In summary,our study provides an identification of aberrant IncRNAs alterations involved in inflamnation upon VILI,and IncRNAs-mediated regulatory patterns may contribute to VILI inflammation.Part two The role of myeloid-derived suppressor cells in ventilator-induced lung injuryObjective:To study the role of myeloid-derived suppressor cells(MDSCs)in the process of ventilator-induced lung injury(VILI)in mice.Methods:We established the mouse model of VILI using mechanical ventilation with a high tidal volume(20 mL/kg)for 4 hours.The inflammation-induced MDSCs(iMDSCs)were sorted from the bone marrow of cecal ligation and puncture mice using flow cytometry.The experimental group included control group,VILI group,and VILI with iMDSCs adaptive transfer(iMDSCs+VILI).We adapted iMDSCs through retrobulbar angular vein one hour before the mechanical ventilation.The mice in control group were anesthetized and maintained spontaneous respiration,and mice in VILI group were administered with equal volume phosphate buffer.We then collected the bronchoalveolar lavage fluid(BALF)and lung samples 6 hours after the terminate of mechanical ventilation.The concentrations of proteins,inflamnatory mediator levels(including IL-6,TNF-?,and MCP-1),and numbers of white blood cells in BALF were measured.Finally,the histopathological changes in the lungs were determined of each group.Results:The concentrations of protein,levels of inflammatory mediators,count of white blood cells were all significantly higher than those in the control group(all P<0.05).Histological examinations showed that the infiltration of inflammatory cells,alveolar septal thickening,and alveolar structure destruction were increased in the VILI mice in contrary to the control group.All the above indicators of lung injury were significantly decreased after the adaptive transfer of iMDSCs into VILI mice(all P<0.05).Conclusions:MDSCs could alleviate the inflanrnatory response of VILI mice,which might be a targeted therapy in the future.