Ly2228820

To investigate the role of MAPK activity in ozone-associated IL-8 induction, the ERK1/2 and p38 kinase inhibitors SCH772984 and LY2228820 (Cayman Chemical, Ann Arbor, MI), respectively, were added to cell media to a final concentration of 250 nM with 0.2% DMSO during media change two hours prior to ozone exposure. These remained in the media throughout exposure until harvest. While SCH772984 prevents ERK1/2 phosphorylation and inhibits its kinase activity, LY2228820 inhibits the kinase activity of p38 but does not prevent it from being phosphorylated^{31 (link),32 (link)}. Thus, to verify ERK1/2 and p38 kinase activity inhibition, we examined the phosphorylation of the downstream targets ribosomal s6 kinase (RSK) and mitogen activated protein kinase-activated protein kinase 2 (MK2), respectively via Western blotting. As a positive control for p38 and ERK1/2 activation, primary cells were stimulated with media that contained 5% FBS and 5 μg/mL LPS for four hours.