RESULTS: IL-1β significantly and consistently increased MAP3K8 expression after 2 h in A549, BEAS-2B and NHBE cells. Phosphorylation of MAP3K8 occurred at 20 min after IL-1β stimulation and MAP3K8 protein was degraded at 30 min. MAP3K8 knockdown significantly reduced IL-6, IL-8 levels after IL-1β stimulation and yielded a 10-fold enhancement of the anti-inflammatory effects of dexamethasone. Phosphorylation of ERK1/2 (P-ERK1/2) and phosphorylation of SAPK/JNK (P-SAPK/JNK) decreased at 30 min after IL-1β stimulation with MAP3K8 knockdown. The combination of dexamethasone and MAP3K8 knockdown resulted in greater inhibition of phosphorylated ERK1/2 and SAPK/JNK. Nineteen genes including MMP1, MMP3, MMP10, ITGB8, LAMC2 and PLAT (P corrected < 0.01 respectively) demonstrated a distinct altered temporal response to IL-1β following suppression of MAP3K8. However, putative MAP3K8 inhibitors including Tpl2-1, Tpl2-2 and GSK2222867A only showed inhibition of IL-6 and IL-8 production at a high dose.
CONCLUSIONS: These results confirm that MAP3K8 is a key mediator of the early inflammatory response and that it is a potential target in inflammatory diseases. However, current tool compounds do not effectively inhibit its effects.
结果:IL-1β在A549,BEAS-2B和NHBE细胞中2小时后显着且一致地增加了MAP3K8的表达。IL-1β刺激后20分钟发生MAP3K8的磷酸化,30分钟时MAP3K8蛋白降解。MAP3K8敲低在IL-1β刺激后显著降低IL-6、IL-8水平,并使地塞米松的抗炎作用增强10倍。IL-1β刺激MAP3K8敲除后30分钟,ERK1/2(P-ERK1/2)的磷酸化和SAPK/JNK(P-SAPK/JNK)的磷酸化降低。地塞米松和MAP3K8敲低的组合导致磷酸化ERK1/2和SAPK/JNK的更大抑制。包括MMP1,MMP3,MMP10,ITGB8,LAMC2和PLAT在内的19个基因(分别校正为P<0.01)显示出抑制MAP3K8后对IL-1β的明显改变的时间反应。然而,假定的MAP3K8抑制剂,包括Tpl2-1,Tpl2-2和GSK2222867A在高剂量时仅显示出IL-6和IL-8产生的抑制。
结论:这些结果证实MAP3K8是早期炎症反应的关键介质,并且是炎性疾病的潜在靶标。然而,目前的工具化合物不能有效地抑制其作用。