MMP1 and systemic sclerosis: We thus examined the expression of the genes involved in collagen synthesis (Collagen Type I Alpha 1, Col1a1, and Collagen Type I Alpha 2, Col1a2) or its degradation (Matrix Metallopeptidase 1, MMP1) and in recruitment of immune cells (C-C Motif Chemokine Ligand 2, CCL2) in HD dermal fibroblasts upon stimulation with HD or SSc patients-derived MPs.