title: Cytokine regulation by MAPK activated kinase 2 in keratinocytes exposed to sulfur mustard.
abstract: 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.
authors.affiliation: Cell and Molecular Biology Branch, US Army Medical Research Institute of Chemical Defense, 3100 Ricketts Point Road, Aberdeen Proving Ground, 21010 MD, United States. Electronic address: echepchumba.k.yego.ctr@us.army.mil.
authors.forename: E Chepchumba K
authors.initials: EC
authors.lastname: Yego
authors.forename: James F
authors.initials: JF
authors.lastname: Dillman
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D002478:Cells, Cultured; D002619:Chemical Warfare Agents / Q000737:chemistry / Q000633:toxicity*; D016207:Cytokines / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003879:Dermatologic Agents / Q000037:antagonists & inhibitors / Q000633:toxicity*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D007509:Irritants / Q000037:antagonists & inhibitors / Q000633:toxicity; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D007700:Kinetics; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D009151:Mustard Gas / Q000737:chemistry / Q000633:toxicity*; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering; D015854:Up-Regulation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002619:Chemical Warfare Agents; D016207:Cytokines; D003879:Dermatologic Agents; D047908:Intracellular Signaling Peptides and Proteins; D007509:Irritants; D009151:Mustard Gas; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2
keywords: 3’-UTR; 3′ untranslated region; ARE; ARE/poly(U)-binding/degradation factor 1; AUF1; BRF1; COX-2; Cytokine; ERK; G-CSF; GM-CSF; HBSS; HSP27; Hanks’ balanced salt solution; IL-1β; IL-6; IL-8; JNK; Keratinocytes; LPS; MAPK; MAPK activated kinase 2; MAPK activated kinase 3; MAPK activated kinase 5; MK2/MAPKAPK2; MK3/MAPKAPK3; MK5/MAPKAPK5; NHEK; SM; Sulfur mustard; TNF-α; 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; mitogen activated protein kinase; normal human epidermal keratinocytes; p38; qPCR; quantitative polymerase chain reaction; siRNA; small interfering RNA; sulfur mustard; tristetraprolin; tumor necrosis alpha-α