MMP9 and systemic sclerosis: In contrast, collagen degradation‐related genes (matrix metalloproteinase 3, Mmp3, and Mmp9) were upregulated (Figure S7A, Supporting Information).[37] WB analysis and immunofluorescence images further verified the remarkable downregulation of α‐SMA, Postn, Col1A1, and Col3A1 in BLM‐SSc KO mice (Figure 4F,G; Figure S7B, Supporting Information).