ER-stress mobilization of death-associated protein kinase-1-dependent xenophagy counteracts mitochondria stress-induced epithelial barrier dysfunctionShow others and affiliations
2018 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 293, no 9, p. 3073-3087Article in journal (Refereed) Published
Abstract [en]
The gut microbiome contributes to inflammatory bowel disease (IBD), in which bacteria can be present within the epithelium. Epithelial barrier function is decreased in IBD, and dysfunctional epithelial mitochondria and endoplasmic reticulum (ER) stress have been individually associated with IBD. We therefore hypothesized that the combination of ER and mitochondrial stresses significantly disrupt epithelial barrier function. Here, we treated human colonic biopsies, epithelial colonoids, and epithelial cells with an uncoupler of oxidative phosphorylation, dinitrophenol (DNP), with or without the ER stressor tunicamycin and assessed epithelial barrier function by monitoring internalization and translocation of commensal bacteria. We also examined barrier function and colitis in mice exposed to dextran sodium sulfate (DSS) or DNP and co-treated with DAPK6, an inhibitor of death-associated protein kinase 1 (DAPK1). Contrary to our hypothesis, induction of ER stress (i.e. the unfolded protein response) protected against decreased barrier function caused by the disruption of mitochondrial function. ER stress did not prevent DNP-driven uptake of bacteria; rather, specific mobilization of the ATF6 arm of ER stress and recruitment of DAP K1 resulted in enhanced autophagic killing (xenophagy) of bacteria. Of note, epithelia with a Crohns disease susceptibility mutation in the autophagy gene ATG16L.1 exhibited less xenophagy. Systemic delivery of the DAPK1 inhibitor DAPK6 increased bacterial translocation in DSS- or DNP-treated mice. We conclude that promoting ER stress ATF6 DAPK1 signaling in transporting enterocytes counters the transcellular passage of bacteria evoked by dysfunctional mitochondria, thereby reducing the potential for metabolic stress to reactivate or perpetuate inflammation.
Place, publisher, year, edition, pages
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC , 2018. Vol. 293, no 9, p. 3073-3087
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
URN: urn:nbn:se:liu:diva-147120DOI: 10.1074/jbc.RA117.000809ISI: 000426562800004PubMedID: 29317503OAI: oai:DiVA.org:liu-147120DiVA, id: diva2:1199527
Note
Funding Agencies|Canadian Institutes for Health Research Operating Grant [MPO-126005]; Canadian Institutes for Health Research/Canadian Association of Gastroenterology/Allergan, Inc.; Alberta Innovates-Health Solutions post-doctoral fellowships
2018-04-202018-04-202018-04-20