title: Myocardial depressant effects of interleukin 6 in meningococcal sepsis are regulated by p38 mitogen-activated protein kinase.
abstract: OBJECTIVE
  Myocardial failure, leading to inotrope-unresponsive shock, is the predominant cause of death in meningococcal and other forms of septic shock. Proinflammatory cytokines released in septic shock are known to have myocardial depressant effects. We previously showed that interleukin 6 is a major myocardial depressant factor in children with meningococcal septicemia. In the current study, we aimed to investigate the mechanisms by which interleukin 6 induces myocardial failure in meningococcal sepsis and to identify potential novel therapeutic targets.
  
  
  METHODS
  Laboratory-based study.
  
  
  METHODS
  University hospital and laboratories.
  
  
  METHODS
  Children with a clinical diagnosis of meningococcal septic shock.
  
  
  METHODS
  We studied interleukin 6-induced signaling events, both in vitro using isolated rat ventricular cardiac myocytes as a model of myocardial contractility and in whole blood from children with meningococcal sepsis.
  
  
  METHODS
  None.
  
  
  RESULTS
  We demonstrated involvement of Janus kinase 2, phosphatidylinositol 3-kinase, Akt, and p38 mitogen-activated protein kinase in interleukin 6-induced negative inotropy in isolated cardiac myocytes. Inhibition of p38 mitogen-activated protein kinase not only reversed interleukin 6-induced myocardial depression in both rat and human myocytes, but restored inotrope responsiveness. Cardiomyocytes transduced with dominant-negative p38 mitogen-activated protein kinase showed no interleukin 6-induced myocardial depression. To investigate p38 mitogen-activated protein kinase in vivo, we profiled global RNA expression patterns in peripheral blood of children with meningococcal septicemia. Transcripts for genes mapping to the p38 mitogen-activated protein kinase pathway showed significantly altered levels of abundance with a high proportion of genes of this pathway affected.
  
  
  CONCLUSIONS
  Our findings demonstrate an integral role of the p38 mitogen-activated protein kinase pathway in interleukin 6-mediated cardiac contractile dysfunction and inotrope insensitivity. Dysregulation of the p38 mitogen-activated protein kinase pathway in meningococcal septicemia suggests that this pathway may be an important target for novel therapies to reverse myocardial dysfunction in patients with meningococcal septic shock who are not responsive to inotropic support.
authors.affiliation: Department of Paediatrics, Imperial College London, London, UK. n.pathan@imperial.ac.uk
authors.forename: Nazima
authors.initials: N
authors.lastname: Pathan
authors.forename: Joanne L
authors.initials: JL
authors.lastname: Franklin
authors.forename: Hariklia
authors.initials: H
authors.lastname: Eleftherohorinou
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Wright
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Hemingway
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Waddell
authors.forename: Michael
authors.initials: M
authors.lastname: Griffiths
authors.forename: Jayne L
authors.initials: JL
authors.lastname: Dennis
authors.forename: David A
authors.initials: DA
authors.lastname: Relman
authors.forename: Sian E
authors.initials: SE
authors.lastname: Harding
authors.forename: Michael
authors.initials: M
authors.lastname: Levin
mesh_terms: D000293:Adolescent; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D005260:Female; D015870:Gene Expression; D006801:Humans; D007223:Infant; D015850:Interleukin-6 / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D053614:Janus Kinase 2 / Q000502:physiology; D008297:Male; D008589:Meningococcal Infections / Q000097:blood / Q000235:genetics / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D012313:RNA / Q000097:blood / Q000235:genetics; D051381:Rats; D050796:STAT3 Transcription Factor / Q000378:metabolism; D012772:Shock, Septic / Q000097:blood / Q000235:genetics / Q000503:physiopathology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000097:blood / Q000235:genetics / Q000502:physiology*
chemical_list: D002316:Cardiotonic Agents; D015850:Interleukin-6; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494088:Stat3 protein, rat; D012313:RNA; D053614:Janus Kinase 2; D048051:p38 Mitogen-Activated Protein Kinases; D007545:Isoproterenol