Connexin 43 Upregulation in Mouse Lungs during Ovalbumin-Induced Asthma

PLoS One. 2015 Dec 2;10(12):e0144106. doi: 10.1371/journal.pone.0144106. eCollection 2015.

Abstract

Background: Connexin (Cx)-based gap junction channels play important roles in the inflammatory response. Cx43 is involved in the pathogenesis of some lung diseases such as acute lung injury. However, the Cx43 expression in asthma is unclear. In the present study, we used a murine model of ovalbumin (OVA)-induced allergic airway disease to examine the levels of Cx43 and analyze the relationship between Cx43 and airway inflammation in allergic airway disease.

Methods: Asthma was induced in mice via sensitization and challenge with OVA. Cx43 mRNA and protein expression levels were investigated via QT-PCR, western blot, and immunohistochemistry 0 h, 8 h, 1 d, 2 d and 4 d after the first challenge. The relationship between Cx43 protein levels and inflammatory cell infiltration, cytokine levels was analyzed.

Results: The OVA-induced mice exhibited typical pathological features of asthma, including airway hyper-responsiveness; strong inflammatory cell infiltration surrounding the bronchia and vessels; many inflammatory cells in the bronchoalveolar lavage fluid (BALF); higher IL-4, IL-5 and IL-13 levels; and high OVA specific IgE levels. Low Cx43 expression was detected in the lungs of control (PBS) mice. A dramatic increase in the Cx43 mRNA and protein levels was found in the asthmatic mice. Cx43 mRNA and protein expression levels increased in a time-dependent manner in asthma mice, and Cx43 was mostly localized in the alveolar and bronchial epithelial layers. Moreover, lung Cx43 protein levels showed a significant positive correlation with inflammatory cell infiltration in the airway and IL-4 and IL-5 levels in the BALF at different time points after challenge. Interestingly, the increase in Cx43 mRNA and protein levels occurred prior to the appearance of the inflammatory cell infiltration.

Conclusion: Our data suggest that there is a strong upregulation of Cx43 mRNA and protein levels in the lungs in asthma. Cx43 levels also exhibited a positive correlation with allergic airway inflammation. Cx43 may represent a target to treat allergic airway diseases in the future.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Asthma / chemically induced*
  • Asthma / genetics*
  • Asthma / pathology
  • Bronchoalveolar Lavage Fluid / chemistry
  • Connexin 43 / genetics*
  • Female
  • Inflammation / genetics
  • Inflammation / pathology
  • Interleukin-13 / genetics
  • Interleukin-4 / genetics
  • Interleukin-5 / genetics
  • Lung / drug effects
  • Lung / pathology*
  • Mice
  • Mice, Inbred BALB C
  • Ovalbumin / pharmacology*
  • RNA, Messenger / genetics
  • Respiratory Hypersensitivity / genetics
  • Respiratory Hypersensitivity / pathology
  • Up-Regulation / genetics*

Substances

  • Connexin 43
  • Interleukin-13
  • Interleukin-5
  • RNA, Messenger
  • Interleukin-4
  • Ovalbumin

Grants and funding

This study was supported by grants from the NSFC for Excellent Young Scholars (81322012 to Prof. QL Fu), NCET-13-0608 for Prof. QL Fu, NSFC (81373174, 81170896, 81272062, 81273212 and 81471832), the Science and Technology Foundation of Guangdong Province, China (2011B031800243, 2012B031800045 and 2015B020226002), the Fundamental Research Funds for the Central Universities (13ykzd07) and the Industry Foundation of the Ministry of Health of China (201202005).