MMP12 and systemic sclerosis: Interestingly, SSc serum was demonstrated to exert a pro-EndoMT effect on healthy dermal microvascular ECs (MVECs), presumably through the MMP-12-dependent cleavage of urokinase-type plasminogen activator receptor (uPAR), which is also known to be involved in SSc defective angiogenesis and the fibroblast-to-myofibroblast transition [12,14].