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. 2020 Jun 4;5(11):e133772. doi: 10.1172/jci.insight.133772

Figure 4. MMP-9 inhibition allows melanocyte stabilization both in vitro and in vivo.

Figure 4

(A–C) Reconstructed human pigmented epidermis (RHPE) were treated for 24 hours in the presence or absence of increasing concentrations of active MMP-9. (A) Representative immunofluorescence staining of Melan-A (red) and E-cadherin (green). Dashed lines represent the dermoepidermal layer. Arrows show suprabasal melanocytes in the different conditions. Scale bar: 20 μm. (B) Proportion of suprabasal melanocytes in the different conditions. (C) Assessment by ELISA of soluble E-cadherin levels in cell-free supernatants. (D–F) RHPE were treated for 24 hours in the presence or absence of 10 ng/mL of TNF-α and IFN-γ and/or 1, 10 or 100 μM of MMP-9 inhibitors Ab142180 or SB-3CT. (D) Representative immunofluorescence staining of Melan-A (red) and E-cadherin (green). Dashed lines represent the dermoepidermal layer. Arrows show suprabasal melanocytes in the different conditions. Scale bar: 20 μm. (E) Proportion of suprabasal melanocytes in the different culture conditions. (F) Assessment by ELISA of soluble E-cadherin levels in cell-free supernatants. (G–I) The base of C57BL/6 mouse tail was treated daily for 6 days with intradermal injections of saline buffer (control), or the combination of 1 μg of TNF-α and IFN-γ and/or 1.25 mg/mL of SB-3CT. (G) In vivo schema of C57BL/6 mice treatment. (H) Representative immunofluorescence analysis of Melan-A (red) and E-cadherin (green) staining in the different groups. Dashed lines represent the dermoepidermal layer. Arrows show suprabasal melanocytes. Scale bars: 20 μm. (I) Proportion of suprabasal melanocytes was assessed in the different groups (n = 7–9). Data in B, C, E, F, and I show mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001; ****P < 0.0001, calculated with 2-tailed Mann-Whitney test.