title: Vasoactive intestinal peptide prevents PKCε-induced intestinal epithelial barrier disruption during EPEC infection.
abstract: We previously showed that vasoactive intestinal peptide (VIP) protects against bacterial pathogen-induced epithelial barrier disruption and colitis, although the mechanisms remain poorly defined. The aim of the current study was to identify cellular pathways of VIP-mediated protection with use of pharmacological inhibitors during enteropathogenic Escherichia coli (EPEC) infection of Caco-2 cell monolayers and during Citrobacter rodentium-induced colitis. EPEC-induced epithelial barrier disruption involved the PKC pathway but was independent of functional cAMP, Rho, and NF-κB pathways. VIP mediated its protective effects by inhibiting EPEC-induced PKC activity and increasing expression of the junctional protein claudin-4. Short-term treatment with TPA, which is known to activate PKC, was inhibited by VIP pretreatment, while PKC degradation via long-term treatment with TPA mimicked the protective actions of VIP. Immunostaining for specific PKC isotypes showed upregulated expression of PKCθ and PKCε during EPEC infection. Treatment with specific inhibitors revealed a critical role for PKCε in EPEC-induced barrier disruption. Furthermore, activation of PKCε and loss of barrier integrity correlated with claudin-4 degradation. In contrast, inhibition of PKCε by VIP pretreatment or the PKCε inhibitor maintained membrane-bound claudin-4 levels, along with barrier function. Finally, in vivo treatment with the PKCε inhibitor protected mice from C. rodentium-induced colitis. In conclusion, EPEC infection increases intracellular PKCε levels, leading to decreased claudin-4 levels and compromising epithelial barrier integrity. VIP inhibits PKCε activation, thereby attenuating EPEC-induced barrier disruption.
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: V
authors.initials: V
authors.lastname: Morampudi
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: V S
authors.initials: VS
authors.lastname: Conlin
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: U
authors.initials: U
authors.lastname: Dalwadi
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: X
authors.initials: X
authors.lastname: Wu
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: K C
authors.initials: KC
authors.lastname: Marshall
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: C
authors.initials: C
authors.lastname: Nguyen
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: B A
authors.initials: BA
authors.lastname: Vallance
authors.affiliation: Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; Division of Gastroenterology, British Columbia Children's Hospital, Vancouver, British Columbia, Canada; and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada kjacobson@cw.bc.ca.
authors.forename: K
authors.initials: K
authors.lastname: Jacobson
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D018938:Caco-2 Cells; D002478:Cells, Cultured; D044082:Citrobacter rodentium / Q000472:pathogenicity; D062506:Claudin-4 / Q000235:genetics / Q000378:metabolism; D003092:Colitis / Q000188:drug therapy / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D054308:Enteropathogenic Escherichia coli / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000378:metabolism*; D005260:Female; D019073:HT29 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D051744:Protein Kinase C-epsilon / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology* / Q000627:therapeutic use; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D062506:Claudin-4; D016328:NF-kappa B; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D054460:rho-Associated Kinases; D051744:Protein Kinase C-epsilon
keywords: bacterial infection; cell signaling; inflammatory bowel disease; intestinal epithelial barrier; protein kinase Cε; vasoactive intestinal peptide