Recent published work in our laboratory has shown a profound downregulation of atypical PKC in intestinal epithelial cells under TNF? stimulation, in the DSS model of murine colitis, and in Inflammatory Bowel Disease patients. In this project we will analyze mechanistically the consequences of aPKC loss on cellular functions, signaling pathways, and molecular effectors, known to be essential in the pathophysiological of IBD in these cells. Our preliminary data strongly indicate that a decrease in aPKC activity comparable to that observed in the animal model and in patients, is sufficient to trigger activation of the classic I?B pathway independently of TNFR. This observation opens the possibility that signaling downstream of aPKC may establish a negative feedback that keeps epithelial cells in an """"""""inflamed"""""""" condition even if the original cytokine stimulaton is removed. If our hypothesis is correct, breaking this cycle may help to rapidly correct barrier defects and cytokine secretion by epithelial cells, which would be desirable in chronic intestinal inflammation. Moreover, since these pathways are specific to epithelial cells, understanding them may allow tissue-specific interventions. The mechanistic aspects and the consequences of this phenomenon will be studied in Aim 1. Our preliminary data also shows that a similar transient event occurs in epithelial wounds, suggesting the hypothesis that it may also be involved in the early stages of epithelial restitution, which will b tested in Aim 2. Finally, the molecular mechanisms studied in aims 1 and 2 will be analyzed in in the context of an animal model of colitis in Aim 3. Altogether the project is expeced to establish a totally novel signaling pathway, identify its normal function, and bring new, as ye unsuspected possible therapeutic targets to modulate the epithelial response to inflammation.

Public Health Relevance

Inflammatory Bowel Disease is a multi-factorial aberrant response of the immune system that, among other effects, impacts on the layer of cells lining the intestinal lumen, the epithelium. This project studies a novel intracellular signaling pathway in the epithelium that counteracts the effects of inflammation. Importantly, if our hypothesis is correct, inhibition of this new pathway may contribute to the persistence of the effects of inflammation and may provide new unsuspected therapeutic opportunities.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
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Gastrointestinal Mucosal Pathobiology Study Section (GMPB)
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Grey, Michael J
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University of Miami School of Medicine
Anatomy/Cell Biology
Schools of Medicine
Coral Gables
United States
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Salas, Pedro J; Forteza, Radia; Mashukova, Anastasia (2016) Multiple roles for keratin intermediate filaments in the regulation of epithelial barrier function and apico-basal polarity. Tissue Barriers 4:e1178368
Forteza, Radia; Figueroa, Yolanda; Mashukova, Anastasia et al. (2016) Conditional knockout of polarity complex (atypical) PKC? reveals an anti-inflammatory function mediated by NF-?B. Mol Biol Cell 27:2186-97
Mashukova, Anastasia; Forteza, Radia; Salas, Pedro J (2016) Functional Analysis of Keratin-Associated Proteins in Intestinal Epithelia: Heat-Shock Protein Chaperoning and Kinase Rescue. Methods Enzymol 569:139-54
Hyun, Jinhee; Romero, Laura; Riveron, Reldy et al. (2015) Human intestinal epithelial cells express interleukin-10 through Toll-like receptor 4-mediated epithelial-macrophage crosstalk. J Innate Immun 7:87-101
Kravtsov, Dmitri; Mashukova, Anastasia; Forteza, Radia et al. (2014) Myosin 5b loss of function leads to defects in polarized signaling: implication for microvillus inclusion disease pathogenesis and treatment. Am J Physiol Gastrointest Liver Physiol 307:G992-G1001
Mashukova, Anastasia; Kozhekbaeva, Zhanna; Forteza, Radia et al. (2014) The BAG-1 isoform BAG-1M regulates keratin-associated Hsp70 chaperoning of aPKC in intestinal cells during activation of inflammatory signaling. J Cell Sci 127:3568-77
Forteza, Radia; Wald, Flavia A; Mashukova, Anastasia et al. (2013) Par-complex aPKC and Par3 cross-talk with innate immunity NF-?B pathway in epithelial cells. Biol Open 2:1264-9
Mashukova, Anastasia; Forteza, Radia; Wald, Flavia A et al. (2012) PDK1 in apical signaling endosomes participates in the rescue of the polarity complex atypical PKC by intermediate filaments in intestinal epithelia. Mol Biol Cell 23:1664-74
Mashukova, Anastasia; Wald, Flavia A; Salas, Pedro J (2011) Tumor necrosis factor alpha and inflammation disrupt the polarity complex in intestinal epithelial cells by a posttranslational mechanism. Mol Cell Biol 31:756-65
Wald, Flavia A; Forteza, Radia; Diwadkar-Watkins, Runa et al. (2011) Aberrant expression of the polarity complex atypical PKC and non-muscle myosin IIA in active and inactive inflammatory bowel disease. Virchows Arch 459:331-8

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