Cytokine regulation by MAPK activated kinase 2 in keratinocytes exposed to sulfur mustard.
Uncontrolled inflammation contributes to cutaneous damage following exposure to the warfare agent bis(2-chloroethyl) sulfide (sulfur mustard, SM). Activation of the p38 mitogen activated protein kinase (MAPK) precedes SM-induced cytokine secretion in normal human epidermal keratinocytes (NHEKs). This study examined the role of p38-regulated MAPK activated kinase 2 (MK2) during this process. Time course analysis studies using NHEK cells exposed to 200μM SM demonstrated rapid MK2 activation via phosphorylation that occurred within 15 min. p38 activation was necessary for MK2 phosphorylation as determined by studies using the p38 inhibitor SB203580. To compare the role of p38 and MK2 during SM-induced cytokine secretion, small interfering RNA (siRNA) targeting these proteins was utilized. TNF-α, IL-1β, IL-6 and IL-8 secretion was evaluated 24h postexposure, while mRNA changes were quantified after 8h. TNF-α, IL-6 and IL-8 up regulation at the protein and mRNA level was observed following SM exposure. IL-1β secretion was also elevated despite unchanged mRNA levels. p38 knockdown reduced SM-induced secretion of all the cytokines examined, whereas significant reduction in SM-induced cytokine secretion was only observed with TNF-α and IL-6 following MK2 knockdown. Our observations demonstrate potential activation of other p38 targets in addition to MK2 during SM-induced cytokine secretion.
['Yego|E Chepchumba K|EC|', 'Dillman|James F|JF|']
D000894:Anti-Inflammatory Agents, Non-Steroidal D002478:Cells, Cultured D002619:Chemical Warfare Agents D016207:Cytokines D003879:Dermatologic Agents D006801:Humans D047908:Intracellular Signaling Peptides and Proteins D007509:Irritants D015603:Keratinocytes D007700:Kinetics D020935:MAP Kinase Signaling System D009151:Mustard Gas D010766:Phosphorylation D047428:Protein Kinase Inhibitors D011499:Protein Processing, Post-Translational D017346:Protein Serine-Threonine Kinases D034622:RNA Interference D012333:RNA, Messenger D034741:RNA, Small Interfering D015854:Up-Regulation D048051:p38 Mitogen-Activated Protein Kinases
Cytokine MAPK MAPK activated kinase 2 Keratinocytes Sulfur mustard Sulfur mustard SM p38 mitogen activated protein kinase normal human epidermal keratinocytes NHEK small interfering RNA siRNA TNF-α IL-1β IL-6 IL-8 3’-UTR 3′ untranslated region ARE ARE/poly(U)-binding/degradation factor 1 AUF1 BRF1 COX-2 ERK G-CSF GM-CSF HBSS HSP27 Hanks’ balanced salt solution JNK LPS MAPK activated kinase 3 MAPK activated kinase 5 MK2/MAPKAPK2 MK3/MAPKAPK3 MK5/MAPKAPK5 TTP Vesicant adenosine and uridine rich element butyrate response factor-1 c-jun N-terminal kinase cyclooxygenase- 2 eNOS endothelial nitric oxide synthase extracellular signal regulated kinase granulocyte-colony stimulating factor granulocyte–macrophage colony stimulating factor heat shock protein 27 iNOS inducible nitric oxide synthase interleukin-1β interleukin-6 interleukin-8 lipopolysaccharide miRNA microRNA qPCR quantitative polymerase chain reaction sulfur mustard tristetraprolin tumor necrosis alpha-α