| Autor: |
Roach, KM, Wulff, H, Feghali-Bostwick, C, Amrani, Y, Bradding, P |
| Jazyk: |
angličtina |
| Rok vydání: |
2014 |
| Zdroj: |
Roach, KM; Wulff, H; Feghali-Bostwick, C; Amrani, Y; & Bradding, P. (2014). Increased constitutive αSMA and Smad2/3 expression in idiopathic pulmonary fibrosis myofibroblasts is KCa3.1-dependent. Respiratory Research, 15(1), 155. doi: 10.1186/s12931-014-0155-5. UC Davis: Retrieved from: http://www.escholarship.org/uc/item/4cb1z533 |
| DOI: |
10.1186/s12931-014-0155-5. |
| Popis: |
© 2014 Roach et al.; licensee BioMed Central Ltd. Background: Idiopathic pulmonary fibrosis is a common and invariably fatal disease with limited therapeutic options. Ca2+-activated KCa3.1 potassium channels play a key role in promoting TGFβ1 and bFGF-dependent profibrotic responses in human lung myofibroblasts (HLMFs). We hypothesised that KCa3.1 channel-dependent cell processes regulate HLMF αSMA expression via Smad2/3 signalling pathways. Methods: In this study we have compared the phenotype of HLMFs derived from non-fibrotic healthy control lungs (NFC) with cells derived from IPF lungs. HLMFs grown in vitro were examined for αSMA expression by immunofluorescence (IF), RT-PCR and flow cytommetry. Basal Smad2/3 signalling was examined by RT-PCR, western blot and immunofluorescence. Two specific and distinct KCa3.1 blockers (TRAM-34 200 nM and ICA-17043 [Senicapoc] 100 nM) were used to determine their effects on HLMF differentiation and the Smad2/3 signalling pathways. Results: IPF-derived HLMFs demonstrated increased constitutive expression of both α-smooth muscle actin (αSMA) and actin stress fibres, indicative of greater myofibroblast differentiation. This was associated with increased constitutive Smad2/3 mRNA and protein expression, and increased Smad2/3 nuclear localisation. The increased Smad2/3 nuclear localisation was inhibited by removing extracellular Ca2+or blocking KCa3.1 ion channels with selective KCa3.1 blockers (TRAM-34, ICA-17043). This was accompanied by de-differentiation of IPF-derived HLMFs towards a quiescent fibroblast phenotype as demonstrated by reduced αSMA expression and reduced actin stress fibre formation. Conclusions: Taken together, these data suggest that Ca2+- and KCa3.1-dependent processes facilitate "constitutive" Smad2/3 signalling in IPF-derived fibroblasts, and thus promote fibroblast to myofibroblast differentiation. Importantly, inhibiting KCa3.1 channels reverses this process. Targeting KCa3.1 may therefore provide a novel and effective approach for the treatment of IPF and there is the potential for the rapid translation of KCa3.1-directed therapy to the clinic. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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