MMP12 and Hermansky-Pudlak syndrome: In parallel, MMP-12 levels (Fig. 7c, all P < 0.05 for RSV + LPS group vs. the other groups), BALF inflammatory cells, monocytes, neutrophils, lymphocytes, eosinophils (Fig. 7d, all P < 0.05 for RSV + LPS group vs. the other groups), lung tissue damage (Fig. 7e-i) and HPS (Fig. 7j, all P < 0.001 for RSV + LPS group vs. the other groups) and AHR (Fig. 7k, all P < 0.01 for RSV + LPS group vs. the other groups at methacholine concentrations of 25 mg/ml and 50 mg/ml), were all dramatically reduced in the ERK-inhibitor-treated mice (RL + i ERK group).