LysoPS Binding To G Protein-coupled Receptors Promotes Asthma Inflammation Through MAPK/Erk Pathway

BackgroundBronchial asthma is a common,recurrent,chronic inflammatory airway disease that manifests as airway hyperresponsiveness,episodic airway obstruction,and pulmonary hypoplasia,and long-term poor control can lead to airway remodeling resulting in irreversible damage to lung function.The pathogenesis of asthma is a complex process and markedly heterogeneous;therefore it is significant to improve the diagnosis rate and treatment rate of asthma as well as to explore new therapeutic targets.Lysophospholipids(LysoPLs)play multiple roles in tumor,neurogenesis,vascular development,and immune regulation.Lysophospholipids are now recognized to have a wide range of lipid mediator functions that are mediated through G protein-coupled receptors(GPCRs)specific to each lysophospholipid.Lysophosphatidylserine(LysoPS)is one of the less studied members of the Lysophospholipids family.The biological activity of LysoPS has not been fully elucidated,and its role in asthma has been even less reported.It has been shown that LysoPS can induce a variety of cellular responses,including modulation of neutrophil clearance by macrophages and promotion of neutrophil inflammation regression;promotion of mast cell degranulation and as a sensitizer to promote histamine release from mast cells;and inhibition of CD4+lymphocyte proliferation and treg cell differentiation.Some research data suggest that it plays a unique signaling role in the early stages of acute inflammation and its coordinated process of inflammation regression.LysoPS-specific G protein-coupled receptors(GPCRs)including P2Y10,GPR34 and GPR174 have been identified.Previous studies have shown a relationship between GPR34 and MAPK/erk signaling pathway.The biological activity of LysoPS has not been fully elucidated,and its role in asthma has been even less reported.In this study,we intend to investigate the role and mechanism of lysophosphatidylserine and its specific G protein-coupled receptors in asthma airway inflammation by constructing an animal model of asthmaObjectives1.To investigate the level of LysoPS in animal asthma models and its relationship with airway inflammation.2.Human airway epithelial cells(16HBE)were intervened with LysoPS to observe airway inflammation and changes in airway epithelial mesenchymal transition and airway remodeling markers3.To investigate the effect of LysoPS on MAPK/Erk signaling pathway in human airway epithelial cellsMethodsBala/c mice were sensitized with OVA to construct an asthma model,and plasma LysoPS levels in the animal model were measured by liquid chromatography-mass spectrometry(LC-MS).Immunoblotting assay(Western Blot),hematoxylin-eosin(H&E)staining,immunohistochemical staining(IHC),enzyme-linked immunosorbent assay(ELISA)and real-time fluorescence quantitative PCR(qPCR)were used to study the role and mechanism of LysoPS binding to G protein-coupled receptors in asthma inflammation through MAPK/Erk signaling pathway.Results1.The lung tissue,bronchoalveolar lavage fluid(BALF)and plasma specimens of the asthma mice models showed pathological manifestations related to airway inflammation and remodeling.H&E staining showed that the small airways of the asthmatic mice were infiltrated with inflammatory cells around the airways,and the airway epithelium was damaged and detached to different degrees,and inflammatory exudation was seen in the lumen.Immunohistochemical staining and Masson staining showed that the expression of α-SMA and collagen fibers were higher in asthmatic mice than in the normal control group.2.Nine LysoPS were detected in mouse plasma by liquid chromatography-mass spectrometry.Among them,plasma LPS 18:2,LPS 22:6,LPS 20:4,LPS 20:5,LPS 22:4,LPS 22:5 levels were elevated in asthmatic mice compared with controls and were positively correlated with alveolar lavage fluid and plasma IL-4,IL-5,IL-13,IL-17A levels and negatively correlated with IL-10.3.After adding LysoPS stimulation to 16HBE,the expression of P2Y10,GPR174,GPR34 were increased,inflammatory factor expression was increased,and MAPK/Erk signaling pathway-related indexes were elevated.Conclusion1.LysoPS levels were elevated in mouse model of asthma and positively correlated with the degree of airway inflammation2.In vitro,LysoPS binding to G protein-coupled receptors promotes the inflammatory response of airway epithelial cells through the MAPK/Erk signaling pathway.