STIM1/Orai1-mediated Ca 2+ influx contributes to the ASM phenotype modulation and ASM-related ECM deposition in asthma

Abstract

Abstract Background: Phenotype modulation of airway smooth muscle cells (ASMC), defined as a more proliferative/synthetic type switched from contractile cells, plays an important role in airway remodeling of asthma. STIM1 and Orai1, the key aspects mediating store-operated Ca2+ entry (SOCE), have been shown to promote ASMC proliferation and migration. In this study, we explored the role of STIM1/Orai1-mediated SOCE in ASMC phenotype transition, and further investigated their involvement in the extracellular matrix (ECM) deposition in asthma. Methods: The ASMCs from C57BL/6 mice were prepared and incubated with PDGF-BB to induced the phenotype switching. SKF-96365, an inhibitor of STIM1/Orai1, was used to detect the effect of SOCE in the ASMC phenotype transition and ASMC-related ECM doposition. Cell counting kit-8 assay, immunocytochemistry staining, enzyme-linked immunosorbent assay, and western blot assay were employed to detect the ASMC’s proliferation and the expressions of contractile proteins, inflammatory cytokines as well as exacellular matrix. Moreover, we prepared the asthmatic mice model with SKF-96365 intranasal or intratracheal instillation and western blot assay were employed to determine the effect of SOCE repression in ECM deposition in vivo. Results: We prepared the “proliferative/synthetic” type ASMCs with PDGF-BB treatment. and detected the increased expressions of STIM1 and Orai1 in phenotype switched ASMCs, accompanied by an enhance of SOCE. SKF-96365 could obviously block the activation of SOCE in ASMC. Meanwhile, the addition of SKF-96365 in phenotype switched ASMCs could significantly attenuate their increased proliferation ability, inflammatory cytokines secretion, and decreased contractile proteins contents induced by PDGF-BB. Moreover, we detected that PDGF-BB-induced “proliferative/synthetic” ASMCs can produce more ECM components, including collagen I, elastin and fibronectin, and metalloproteinases (MMPs) such as MMP2 and MMP9, which could be inhibited by the STIM1/Orai1 blocker SKF-96365. In vivo experiments also showed the similar results that SKF-96365 reduced the ECM deposition and MMPs production in the asthmatic mice model. Conclusion: These observations demonstrated the prominent role of STIM1/Orai1-mediated SOCE in the phenotype modulation of ASMCs and their influence in the ASMC-induced excessive and altered ECM deposition. Therefore, our results indicated that STIM1/Orai1-mediated SOCE may take part in the airway remodeling of asthma.