Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells

Latifa Chachi, Aarti Shikotra, S. Mark Duffy, Omar Tliba, Christopher Brightling, Peter Bradding, Yassine Amrani

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Identifying the factors responsible for relative glucocorticosteroid (GC) resistance present in patients with severe asthma and finding tools to reverse it are of paramount importance. In asthma we see in vivo evidence of GC-resistant pathways in airway smooth muscle (ASM) bundles that can be modeled in vitro by exposing cultured ASM cells to TNF-α/IFN-γ. This action drives GC insensitivity via protein phosphatase 5-dependent impairment of GC receptor phosphorylation. In this study, we investigated whether K Ca3.1 ion channels modulate the activity of GC-resistant pathways using our ASM model of GC insensitivity. Immunohistochemical staining of endobronchial biopsies revealed that KCa3.1 channels are localized to the plasma membrane and nucleus of ASM in both healthy controls and asthmatic patients, irrespective of disease severity. Western blot assays and immunofluorescence staining confirmed the nuclear localization of K Ca3.1 channels in ASM cells. The functional importance of K Ca3.1 channels in the regulation of GC-resistant chemokines induced by TNF-α/IFN-γ was assessed using complementary inhibitory strategies, including KCa3.1 blockers (TRAM-34 and ICA-17043) or KCa3.1-specific small hairpin RNA delivered by adenoviruses. K Ca3.1 channel blockade led to a significant reduction of fluticasone-resistant CX3CL1, CCL5, and CCL11 gene and protein expression. KCa3.1 channel blockade also restored fluticasone-induced GC receptor-α phosphorylation at Ser211 and transactivation properties via the suppression of cytokine-induced protein phosphatase 5 expression. The effect of KCa3.1 blockade was evident in ASM cells from both healthy controls and asthmatic subjects. In summary, KCa3.1 channels contribute to the regulation of GC-resistant inflammatory pathways in ASM cells: blocking KCa3.1 channels may enhance corticosteroid activity in severe asthma.

Original languageEnglish (US)
Pages (from-to)2624-2636
Number of pages13
JournalJournal of Immunology
Volume191
Issue number5
DOIs
StatePublished - Sep 1 2013

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Smooth Muscle Myocytes
Steroids
Smooth Muscle
Asthma
Phosphorylation
Staining and Labeling
Ion Channels
Chemokines
Adenoviridae
Small Interfering RNA
Transcriptional Activation
Fluorescent Antibody Technique
Adrenal Cortex Hormones
Western Blotting
Cell Membrane
Cytokines
Biopsy
Gene Expression
Proteins
Fluticasone

All Science Journal Classification (ASJC) codes

  • Immunology
  • Medicine(all)

Cite this

Chachi, L., Shikotra, A., Duffy, S. M., Tliba, O., Brightling, C., Bradding, P., & Amrani, Y. (2013). Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells. Journal of Immunology, 191(5), 2624-2636. https://doi.org/10.4049/jimmunol.1300104
Chachi, Latifa ; Shikotra, Aarti ; Duffy, S. Mark ; Tliba, Omar ; Brightling, Christopher ; Bradding, Peter ; Amrani, Yassine. / Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells. In: Journal of Immunology. 2013 ; Vol. 191, No. 5. pp. 2624-2636.
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Chachi, L, Shikotra, A, Duffy, SM, Tliba, O, Brightling, C, Bradding, P & Amrani, Y 2013, 'Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells', Journal of Immunology, vol. 191, no. 5, pp. 2624-2636. https://doi.org/10.4049/jimmunol.1300104

Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells. / Chachi, Latifa; Shikotra, Aarti; Duffy, S. Mark; Tliba, Omar; Brightling, Christopher; Bradding, Peter; Amrani, Yassine.

In: Journal of Immunology, Vol. 191, No. 5, 01.09.2013, p. 2624-2636.

Research output: Contribution to journalArticle

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AU - Chachi, Latifa

AU - Shikotra, Aarti

AU - Duffy, S. Mark

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AU - Brightling, Christopher

AU - Bradding, Peter

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Chachi L, Shikotra A, Duffy SM, Tliba O, Brightling C, Bradding P et al. Functional KCa3.1 channels regulate steroid insensitivity in bronchial smooth muscle cells. Journal of Immunology. 2013 Sep 1;191(5):2624-2636. https://doi.org/10.4049/jimmunol.1300104