Figure 9.

P2Y₂ activation by ATP increases collagen synthesis in CFs and is ERK dependent. Collagen synthesis was measured by a collagenase-sensitive [³H]proline incorporation assay. A) ATP (10 μM for 24 h) increased collagen synthesis by 50% (P<0.01) and was blunted with 50 μM suramin (P<0.001). B) siRNA knockdown of P2Y₂ receptor expression reduced ATP-stimulated collagen synthesis (at 10 and 100 μM) over 24 h (P<0.001). C) MEK/ERK inhibition with 10 μM U0126 (U0) prevented ATP-stimulated collagen synthesis (P<0.001). Data are presented as means ± se of 3 independent experiments. **P < 0.01, ***P < 0.001 vs. untreated control; ⁺⁺⁺P < 0.001.