title: Conditional knockout of polarity complex (atypical) PKCι reveals an anti-inflammatory function mediated by NF-κB.
abstract: The conserved proteins of the polarity complex made up of atypical PKC (aPKC, isoforms ι and ζ), Par6, and Par3 determine asymmetry in several cell types, from Caenorhabditis elegans oocytes to vertebrate epithelia and neurons. We previously showed that aPKC is down-regulated in intestinal epithelia under inflammatory stimulation. Further, expression of constitutively active PKCι decreases NF-κB activity in an epithelial cell line, the opposite of the effect reported in other cells. Here we tested the hypothesis that aPKC has a dual function in epithelia, inhibiting the NF-κB pathway in addition to having a role in apicobasal polarity. We achieved full aPKC down-regulation in small intestine villi and colon surface epithelium using a conditional epithelium-specific knockout mouse. The results show that aPKC is dispensable for polarity after cell differentiation, except for known targets, including ROCK and ezrin, claudin-4 expression, and barrier permeability. The aPKC defect resulted in increased NF-κB activity, which could be rescued by IKK and ROCK inhibitors. It also increased expression of proinflammatory cytokines. In contrast, expression of anti-inflammatory IL-10 decreased. We conclude that epithelial aPKC acts upstream of multiple mechanisms that participate in the inflammatory response in the intestine, including, but not restricted to, NF-κB.
authors.affiliation: Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136.
authors.forename: Radia
authors.initials: R
authors.lastname: Forteza
authors.affiliation: Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Figueroa
authors.affiliation: Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136 Department of Physiology, Nova Southeastern University, Ft. Lauderdale, FL 33314.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Mashukova
authors.affiliation: Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136.
authors.forename: Vipin
authors.initials: V
authors.lastname: Dulam
authors.affiliation: Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136 psalas@miami.edu.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Salas
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D015536:Down-Regulation; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D007527:Isoenzymes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism*; D011493:Protein Kinase C / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D000099293:Protein Kinase C-lambda
chemical_list: D007527:Isoenzymes; D016328:NF-kappa B; D011493:Protein Kinase C; D000099293:Protein Kinase C-lambda