Figure 2.

Formaldehyde enhances myosin light-chain phosphatase (MYPT1) phosphorylation in HASM cells. Rho-associated kinase (ROCK) activity was determined in HASM cell lysates by assessing phosphorylated (p) MYPT1 (pMYPT1) levels, either by ELISA or immune blotting. (A) Formaldehyde (0.2 ppm) increased the basal ROCK activity in HASM cells compared with PBS-treated control (mean ± SEM; n = 3 donors; *P < 0.05). (B) Phosphorylation of MYPT1, the downstream target of ROCK, was increased in HASM cells exposed to 0.2 ppm formaldehyde. Stimulation with the contractile agonist carbachol (10 μM for 10 min) increased the pMYPT1 in PBS-treated HASM cells but not in formaldehyde-treated cells (blot representative of five experiments). Formaldehyde exposure has little effect on the expression of (C) ROCK1/2 mRNA (mean ± SEM, n = 3) or (D) ROCK2 protein in HASM cells (representative blot for n = 3; mean ± SEM). CCh, carbachol concentration.