p38 MAP kinase activation by Clostridium difficile toxin A mediates monocyte necrosis, IL-8 production, and enteritis

J Clin Invest. 2000 Apr;105(8):1147-56. doi: 10.1172/JCI7545.

Abstract

Clostridium difficile toxin A causes acute neutrophil infiltration and intestinal mucosal injury. In cultured cells, toxin A inactivates Rho proteins by monoglucosylation. In monocytes, toxin A induces IL-8 production and necrosis by unknown mechanisms. We investigated the role of mitogen-activated protein (MAP) kinases in these events. In THP-1 monocytic cells, toxin A activated the 3 main MAP kinase cascades within 1 to 2 minutes. Activation of p38 was sustained, whereas stimulation of extracellular signal-regulated kinases and c-Jun NH(2)-terminal kinase was transient. Rho glucosylation became evident after 15 minutes. IL-8 gene expression was reduced by 70% by the MEK inhibitor PD98059 and abrogated by the p38 inhibitor SB203580 or by overexpression of dominant-negative mutants of the p38-activating kinases MKK3 and MKK6. SB203580 also blocked monocyte necrosis and IL-1beta release caused by toxin A but not by other toxins. Finally, in mouse ileum, SB203580 prevented toxin A-induced neutrophil recruitment by 92% and villous destruction by 90%. Thus, in monocytes exposed to toxin A, MAP kinase activation appears to precede Rho glucosylation and is required for IL-8 transcription and cell necrosis. p38 MAP kinase also mediates intestinal inflammation and mucosal damage induced by toxin A.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bacterial Toxins / metabolism
  • Bacterial Toxins / pharmacology*
  • Cell Line
  • Clostridium difficile / immunology*
  • Clostridium difficile / metabolism
  • Enteritis / enzymology
  • Enteritis / immunology*
  • Enteritis / microbiology
  • Enterocolitis, Pseudomembranous / enzymology
  • Enterocolitis, Pseudomembranous / immunology
  • Enterocolitis, Pseudomembranous / microbiology
  • Enterotoxins / metabolism
  • Enterotoxins / pharmacology*
  • Enzyme Activation
  • Gene Expression Regulation / drug effects
  • Glycosylation
  • Interleukin-8 / biosynthesis*
  • Interleukin-8 / genetics
  • MAP Kinase Signaling System*
  • Mice
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinase 8
  • Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • Mitogen-Activated Protein Kinases / immunology
  • Mitogen-Activated Protein Kinases / metabolism*
  • Monocytes / immunology*
  • Monocytes / metabolism
  • Monocytes / pathology
  • Neutrophil Infiltration / immunology
  • Neutrophils / immunology
  • p38 Mitogen-Activated Protein Kinases
  • rho GTP-Binding Proteins / immunology
  • rho GTP-Binding Proteins / metabolism

Substances

  • Bacterial Toxins
  • Enterotoxins
  • Interleukin-8
  • tcdA protein, Clostridium difficile
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinase 8
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • rho GTP-Binding Proteins