Airway Hyperresponsiveness in Asthma Model Occurs Independently of Secretion of [beta]1 Integrins in Airway Wall and Focal Adhesions Proteins Down Regulation

• Published in: Journal of cellular biochemistry Vol. 117; no. 10; p. 2385
• Main Authors: Alvarez-Santos, Mayra, Carbajal, Verónica, Tellez-Jimenez, Olivia, Martinez-Cordero, Erasmo, Ruiz, Victor, Hernandez-Pando, Rogelio, Lascurain, Ricardo, Santibanez-Salgado, Alfredo, Bazan-Perkins, Blanca
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.10.2016
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.25536

The extracellular domains of some membrane proteins can be shed from the cell. A similar phenomenon occurs with [beta]1 integrins ([alpha]1[beta]1 and [alpha]2[beta]1) in guinea pig. The putative role of [beta]1 integrin subunit alterations due to shedding in airway smooth muscle (ASM) in an allergic asthma model was evaluated. Guinea pigs were sensitized and challenged with antigen. Antigenic challenges induced bronchoobstruction and hyperresponsiveness at the third antigenic challenge. Immunohistochemistry and immunoelectronmicroscopy studies showed that the cytosolic and extracellular domains of the [beta]1 integrin subunit shared the same distribution in airway structures in both groups. Various polypeptides with similar molecular weights were detected with both the cytosolic and extracellular [beta]1 integrin subunit antibodies in isolated airway myocytes and the connective tissue that surrounds the ASM bundle. Flow cytometry and Western blot studies showed that the expression of cytosolic and extracellular [beta]1 integrin subunit domains in ASM was similar between groups. An increment of ITGB1 mRNA in ASM was observed in the asthma model group. RACE-PCR of ITGB1 in ASM did not show splicing variants. The expression levels of integrin-linked kinase (ILK) and paxillin diminished in the asthma model, but not talin. The levels of phosphorylation of myosin phosphatase target subunit 1 (MYPT1) at Thr696 increased in asthma model. Our work suggests that [beta]1 integrin is secreted in guinea pig airway wall. This secretion is not altered in asthma model; nevertheless, [beta]1 integrin cytodomain assembly proteins in focal cell adhesions in which ILK and paxillin are involved are altered in asthma model. J. Cell. Biochem. 117: 2385-2396, 2016. © 2016 Wiley Periodicals, Inc.