title: LAT alleviates Th2/Treg imbalance in an OVA-induced allergic asthma mouse model through LAT-PLC-γ1 interaction.
abstract: BACKGROUND
  Low expression of linker for activation of T cells (LAT) is observed in asthma. LAT and its downstream regulator, phospholipase C-gamma 1 (PLC-γ1) play important roles in the T cell antigen receptor signaling pathway, and their interaction is associated with CD4+cell polarization. Here, we investigated whether LAT can alleviate the imbalance among CD4+cell subgroups and the possible mechanism.
  
  
  METHODS
  An ovalbumin-induced allergic asthma mouse model was established and LAT plasmid was delivered. The pathological changes in lung were evaluated by hematoxylin and eosin and periodic acid-Schiff staining. The typical cytokines released by T helper 2 (Th2) and regulatory T (Treg) cells were measured using enzyme-linked immunosorbent assay and the number of Th1, Th2, and Treg cells were determined using flow cytometry. Lung CD4+T cells were isolated by magnetic isolation. The mRNA expression of LAT and PLC-γ1 was determined by real-time PCR. Co-Immunoprecipitation was performed to confirm the interaction between LAT and PLC-γ1. The protein expression of LAT, PLC-γ1 and corresponding downstream signaling factors were determined by western blotting.
  
  
  RESULTS
  The delivery of LAT DNA to the lung could suppress an overactive Th2 response by decreasing allergic response and Th2 cytokine secretion, and by increasing Treg cytokine secretion. The Th2/Treg imbalance in lung and decreased phosphorylated PLC-γ1 expression in lung CD4+T cells were rectified by LAT DNA delivery. Excessive activation of the Raf-MEK-ERK and PI3K-AKT-CREB pathways after asthma is attenuated by LAT.
  
  
  CONCLUSIONS
  The site-specific delivery of LAT DNA to the lung could suppress an overactive Th2 response and rectify the Th2/Treg imbalance in asthmatic mouse model. LAT-PLC-γ1 interaction may contribute to LAT activity in vivo and LAT protects against asthma partly via Raf-MEK-ERK and PI3K-AKT-CREB pathways. The delivery of LAT DNA could offer a novel and safe strategy for asthma prevention.
authors.affiliation: Department of Respirology Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Respirology Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Li
authors.affiliation: Department of Respirology Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Gu
authors.affiliation: Department of Respirology Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Respirology Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Respirology Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China. Electronic address: guoxj1964@126.com.
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Guo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000276:immunology / Q000628:therapy*; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D008168:Lung / Q000473:pathology*; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010047:Ovalbumin / Q000276:immunology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051966:Phospholipase C gamma / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D048490:raf Kinases / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000485:Allergens; C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; C491734:Lat protein, mouse; D008565:Membrane Proteins; D010750:Phosphoproteins; D010047:Ovalbumin; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt; D048490:raf Kinases; D020930:MAP Kinase Kinase Kinases; D051966:Phospholipase C gamma
keywords: Asthma; LAT; PLC-γ1; Th2 cells; Treg cells