title: MAPK-activated protein kinase 2 contributes to Clostridium difficile-associated inflammation.
abstract: Clostridium difficile infection (CDI) results in toxin-induced epithelial injury and marked intestinal inflammation. Fecal markers of intestinal inflammation correlate with CDI disease severity, but regulation of the inflammatory response is poorly understood. Previous studies demonstrated that C. difficile toxin TcdA activates p38 kinase in tissue culture cells and mouse ilium, resulting in interleukin-8 (IL-8) release. Here, we investigated the role of phosphorylated mitogen-activated protein kinase (MAPK)-activated protein kinase (MK2 kinase, pMK2), a key mediator of p38-dependent inflammation, in CDI. Exposure of cultured intestinal epithelial cells to the C. difficile toxins TcdA and TcdB resulted in p38-dependent MK2 activation. Toxin-induced IL-8 and GROα release required MK2 activity. We found that p38 and MK2 are activated in response to other actin-disrupting agents, suggesting that toxin-induced cytoskeleton disruption is the trigger for kinase-dependent cytokine response. Phosphorylated MK2 was detected in the intestines of C. difficile-infected hamsters and mice, demonstrating for the first time that the pathway is activated in infected animals. Furthermore, we found that elevated pMK2 correlated with the presence of toxigenic C. difficile among 100 patient stool samples submitted for C. difficile testing. In conclusion, we find that MK2 kinase is activated by TcdA and TcdB and regulates the expression of proinflammatory cytokines. Activation of p38-MK2 in infected animals and humans suggests that this pathway is a key driver of intestinal inflammation in patients with CDI.
authors.affiliation: Departments of Pediatrics, Washington University School of Medicine, StLouis, Missouri, USA.
authors.forename: Linda D
authors.initials: LD
authors.lastname: Bobo
authors.forename: Rana E
authors.initials: RE
authors.lastname: El Feghaly
authors.forename: Yee-Shiuan
authors.initials: YS
authors.lastname: Chen
authors.forename: Erik R
authors.initials: ER
authors.lastname: Dubberke
authors.forename: Zhuolin
authors.initials: Z
authors.lastname: Han
authors.forename: Alexandra H
authors.initials: AH
authors.lastname: Baker
authors.forename: Jinmei
authors.initials: J
authors.lastname: Li
authors.forename: Carey-Ann D
authors.initials: CA
authors.lastname: Burnham
authors.forename: David B
authors.initials: DB
authors.lastname: Haslam
mesh_terms: D000818:Animals; D015415:Biomarkers; D045744:Cell Line, Tumor; D016360:Clostridioides difficile; D003015:Clostridium Infections / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D003106:Colon / Q000382:microbiology / Q000473:pathology; D006224:Cricetinae; D016207:Cytokines / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D006801:Humans; D007249:Inflammation / Q000378:metabolism* / Q000382:microbiology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D015415:Biomarkers; D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020830:rac1 GTP-Binding Protein; D000099190:MAP-Kinase-Activated Kinase 2