Claudin-1 expression in airway smooth muscle exacerbates airway remodeling in asthmatic subjects

J Allergy Clin Immunol. 2011 Jun;127(6):1612-21.e8. doi: 10.1016/j.jaci.2011.03.039.


Background: Increased airway smooth muscle (ASM) mass is an essential component of airway remodeling and asthma development, and there is no medication specifically against it. Tight junction (TJ) proteins, which are expressed in endothelial and epithelial cells and affect tissue integrity, might exist in other types of cells and display additional functions in the asthmatic lung.

Objective: The aim of this study was to investigate the existence, regulation, and function of TJ proteins in ASM in asthmatic patients.

Methods: The expression and function of TJ proteins in primary ASM cell lines, human bronchial biopsy specimens, and a murine model of asthma were analyzed by means of RT-PCR, multispectral imaging flow cytometry, immunohistochemistry, Western blotting, 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester staining, tritiated thymidine incorporation, wound-healing assay, and luminometric bead array.

Results: Increased claudin-1 expression was observed in ASM of asthmatic patients, as well as in a murine model of asthma-like airway inflammation. Whereas IL-1β and TNF-α upregulated claudin-1 expression, it was downregulated by the T(H)2 cytokines IL-4 and IL-13 in primary human ASM cells. Claudin-1 was localized to the nucleus and cytoplasm but not to the cell surface in ASM cells. Claudin-1 played a central role in ASM cell proliferation, as demonstrated by increased ASM cell proliferation seen with overexpression and decreased proliferation seen with small interfering RNA knockdown of claudin-1. Overexpression of claudin-1 induced vascular endothelial growth factor and downregulated IL-6, IL-8, and IFN-γ-induced protein 10 production by ASM cells. Claudin-1 upregulation by IL-1β or TNF-α was suppressed by dexamethasone but not by rapamycin, FK506, or salbutamol.

Conclusion: These results demonstrate that claudin-1 might play a role in airway remodeling in asthmatic patients by means of regulation of ASM cell proliferation, angiogenesis, and inflammation.

MeSH terms

  • Airway Remodeling / drug effects
  • Airway Remodeling / genetics
  • Airway Remodeling / physiology*
  • Animals
  • Asthma / genetics
  • Asthma / metabolism*
  • Asthma / pathology
  • Base Sequence
  • Case-Control Studies
  • Cell Line
  • Cell Proliferation
  • Chemokine CXCL10 / metabolism
  • Chemokines / metabolism
  • Claudin-1
  • Cytokines / metabolism
  • DNA Primers / genetics
  • Dexamethasone / pharmacology
  • Disease Models, Animal
  • Female
  • Gene Expression / drug effects
  • Gene Knockdown Techniques
  • Humans
  • Inflammation / pathology
  • Interleukin-13 / pharmacology
  • Interleukin-1beta / pharmacology
  • Interleukin-4 / pharmacology
  • Male
  • Membrane Proteins / antagonists & inhibitors
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Muscle, Smooth / metabolism*
  • Muscle, Smooth / pathology
  • Neovascularization, Pathologic
  • RNA, Small Interfering / genetics
  • Recombinant Proteins / pharmacology
  • Respiratory System / blood supply
  • Respiratory System / metabolism*
  • Respiratory System / pathology
  • Tight Junctions / metabolism
  • Tumor Necrosis Factor-alpha / pharmacology


  • CLDN1 protein, human
  • CXCL10 protein, human
  • Chemokine CXCL10
  • Chemokines
  • Claudin-1
  • Cldn1 protein, mouse
  • Cytokines
  • DNA Primers
  • IL4 protein, human
  • Interleukin-13
  • Interleukin-1beta
  • Membrane Proteins
  • RNA, Small Interfering
  • Recombinant Proteins
  • Tumor Necrosis Factor-alpha
  • Interleukin-4
  • Dexamethasone