p38 MAP kinase activation by Clostridium difficile toxin A mediates monocyte necrosis, IL-8 production, and enteritis
Michel Warny, … , J. Thomas LaMont, Ciarán P. Kelly
Michel Warny, … , J. Thomas LaMont, Ciarán P. Kelly
Published April 15, 2000
Citation Information: J Clin Invest. 2000;105(8):1147-1156. https://doi.org/10.1172/JCI7545.
View: Text | PDF
Article

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

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 NH2-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-1β 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.

Authors

Michel Warny, Andrew C. Keates, Sarah Keates, Ignazio Castagliuolo, Jeff K. Zacks, Samer Aboudola, Amir Qamar, Charalabos Pothoulakis, J. Thomas LaMont, Ciarán P. Kelly

×

Figure 1

Options: View larger image (or click on image) Download as PowerPoint
C. difficile toxin A activates ERK 1/2, p38, and JNK1 in THP-1 monocytic...
C. difficile toxin A activates ERK 1/2, p38, and JNK1 in THP-1 monocytic cells. THP-1 cells were stimulated with toxin A (100 nM) for various periods of time. ERK 1/2 (a), p38 (b), and JNK1 (c) activities were measured by immunoblotting using phosphospecific antibodies (upper panels). The enzymatic activities of ERK2, p38, and JNK1 were measured by in vitro kinase assays after immunoprecipitation (lower panels). Myelin basic protein (MBP) was used as substrate for ERK2 and p38, and GST-c-Jun1-79 was used for JNK1. Toxin A induced rapid (12 minutes) activation of ERK1/2, p38, and JNK1. After 1-hour incubation, p38 activity was increased 6.7-fold as determined by densitometry, whereas ERK and JNK activities had returned to control levels. (d) ERK2 and p38 kinase activities were measured in THP-1 cells either 2 minutes (for ERK2) or 30 minutes (for p38) after stimulation with toxin A (100 nM). Pretreatment with the MEK1/2 inhibitor PD98059 (20 μM) for 30 minutes prevented ERK2 activation, whereas pretreatment with the p38 inhibitor SB203580 (10 μM) blocked p38 kinase activity.