Fig. 4. PN-1 protects DP cells from thrombin-stimulated expression of a myofibroblastic phenotype. (A) Level of SMA protein in cultured wild-type and PN-1^–/– DP cell lysates (upper panel) and in extracts from the hairy skin of wild-type and PN-1^–/– mice (unplucked; unP) and excised 3 days after stimulation of SMA expression by hair plucking (P) (lower panel). (B) Collagen gel contraction by embedded wild-type and PN-1^–/– DP cells after 48 hours in medium containing 10% FCS. ^***Significant difference from wild-type cells (P<0.001). (C) Effect of thrombin inhibition by hirudin (100 µM) on gel contraction by DP cells. (D) Effect of PAR-1-activating peptide (TRAP; 600 µM) or retro-sequence control peptide (600 µM) on the maintenance of contractile properties of wild-type DP cells transferred to a medium containing 1% serum. ^**Significant difference from 1% FCS (P<0.01).