The stiffness‐controlled release of interleukin‐6 by cardiac fibroblasts is dependent on integrin α2β1

Figures

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  FIGURE 1. Young's modulus distributions obtained for soft and stiff gels (mean 2.23 ± 0.80 kPa and 8.28 ± 1.06 kPa for soft and stiff gel samples, respectively). Scan size; 50 µm × 50 µm (256 × 256 pixels). Inset: Example images showing the corresponding elasticity maps illustrating the variability of the moduli around the mean value, ΔE

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  FIGURE 2. FACS profile showing the expression of α2 integrin subunit (A) and β1 integrin subunit (B) within cardiac fibroblasts compared to isotype control and cellular autofluorescence control. Density of α2 integrin subunit (C) and relative expression of ITGA2 gene (D), content of integrin α2β1 (E) in cardiac fibroblasts cultured on soft and stiff gels. Density of α2 integrin subunit (F) and relative expression of ITGA2 gene (G) in cardiac fibroblasts after silencing of α2 integrin subunit (ITGA2), in cells treated with non‐targeting siRNA (NT) and untreated control (CTR). Each value represents a mean ± SD

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  FIGURE 3. Content of IL‐6 within cardiac fibroblast media cultured on soft and stiff gels after 48 hours (A), 96 hours (B) and 144 hours (C). IL‐11 level within cardiac fibroblast after 96 hours of culture (D). Each value represents a mean ± SD

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  FIGURE 4. Level of IL‐6 (A) in cardiac fibroblast after silencing of α2 integrin (ITGA2), in cells treated with non‐targeting siRNA (NT) and untreated control (CTR). Effect (B) of TC‐I 15 (α2β1 integrin inhibitor) applied at concentrations of 10−7 mol/L and 10−8 mol/L, DMSO (TC‐I15 solvent) and untreated control (CTR) on the IL‐6 level in cardiac fibroblasts culture. Effect (C) of FAK 14 inhibitor (FAK kinase inhibitor) applied at concentrations of 10−5 mol/L, 10−6 mol/L, 10−7 mol/L and untreated control (CTR) on the IL‐6 level in cardiac fibroblast culture. Effect (D) of AZM 475 271 (Src kinase inhibitor) applied at concentrations of 10−7 mol/L and 10−8 mol/L, DMSO (AZM 475271 solvent) and untreated control (CTR) on the IL‐6 level in cardiac fibroblasts culture. Each value represents a mean ± SD

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  FIGURE 5. Content of IL‐6 in serum (A) and heart (B) of α2 integrin‐deficient mice (KO) and wild‐type animals (WT). Each value represents a mean ± SD

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  FIGURE 6. Content of sIL‐6R in cardiac fibroblast media cultured on soft and stiff gels (A). Effect of TC‐I 15 (α2β1 integrin inhibitor) applied at concentrations of 10−7 mol/L and 10−8 mol/L, DMSO (TC‐I15 solvent) and untreated control (CTR) on the sIL‐6R level in cardiac fibroblast culture (B). Content of sIL‐6R in heart of α2 integrin‐deficient mice (KO) and wild type (WT) in Figure C. Each value represents a mean ± SD