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Wahlang B, Alexander NC, Li X, Rouchka EC, Kirpich IA, Cave MC. Polychlorinated biphenyls altered gut microbiome in CAR and PXR knockout mice exhibiting toxicant-associated steatohepatitis. Toxicol Rep 2021; 8:536-547. [PMID: 33777700 PMCID: PMC7985695 DOI: 10.1016/j.toxrep.2021.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 12/12/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants associated with non-alcoholic fatty liver disease (NAFLD). Previously, we demonstrated that the PCB mixture, Aroclor1260, exacerbated NAFLD, reflective of toxicant-associated steatohepatitis, in diet-induced obese mice, in part through pregnane-xenobiotic receptor (PXR) and constitutive androstane receptor (CAR) activation. Recent studies have also reported PCB-induced changes in the gut microbiome that consequently impact NAFLD. Therefore, the objective of this study is to examine PCB effects on the gut-liver axis and characterize the role of CAR and PXR in microbiome alterations. C57Bl/6 (wildtype, WT), CAR and PXR knockout mice were fed a high fat diet and exposed to Aroclor1260 (20 mg/kg, oral gavage, 12 weeks). Metagenomics analysis of cecal samples revealed that CAR and/or PXR ablation increased bacterial alpha diversity regardless of exposure status. CAR and PXR ablation also increased bacterial composition (beta diversity) versus WT; Aroclor1260 altered beta diversity only in WT and CAR knockouts. Distinct changes in bacterial abundance at different taxonomic levels were observed between WT and knockout groups; however Aroclor1260 had modest effects on bacterial abundance within each genotype. Notably, both knockout groups displayed increased Actinobacteria and Verrucomicrobia abundance. In spite of improved bacterial diversity, the knockout groups however failed to show protection from PCB-induced hepato- and intestinal- toxicity including decreased mRNA levels of ileal permeability markers (occludin, claudin3). In summary, CAR and PXR ablation significantly altered gut microbiome in diet-induced obesity while Aroclor1260 compromised intestinal integrity in knockout mice, implicating interactions between PCBs and CAR, PXR on the gut-liver axis.
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Key Words
- ACHS, anniston community healthy survey
- AhR, arylhydrocarbon receptor
- Aroclor1260
- CAR, constitutive androstane receptor
- Camp, cathelicidin anti-microbial peptide
- Cdh5, adhesion molecule VE-cadherin
- Cldn, claudin
- Fasn, fatty acid synthase
- Fgf15, fibroblast growth factor 15
- Gut-liver
- HFD, high fat diet
- HOMA, homeostasis model assessment
- IBD, inflammatory bowel diseases
- LDA, linear discriminant analysis
- LEfSe, linear discriminant analysis effect size
- Microbiome
- Muc, mucin
- NAFLD
- NAFLD, nonalcoholic fatty liver disease
- NASH, nonalcoholic steatohepatitis
- OTU, operational taxonomic unit
- Ocln, occludin
- PCBs
- PCBs, polychlorinated biphenyls
- PXR, pregnane-xenobiotic receptor
- Pck1, phosphoenolpyruvate carboxykinase 1
- Ppara, peroxisome-proliferator activated receptor alpha
- RER, respiratory exchange rate
- Reg3g, regenerating islet-derived protein 3-gamma
- TASH
- TASH, toxicant-associated steatohepatitis
- Tff3, trefoil factor 3
- Tjp1, tight junction protein 1
- Tnfa, tumor necrosis factor
- WT, wildtype
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Affiliation(s)
- Banrida Wahlang
- UofL Superfund Research Center, University of Louisville, Louisville, KY, USA
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
- Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA
| | | | - Xiaohong Li
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, USA
- KBRIN Bioinformatics Core, University of Louisville, Louisville, KY, USA
| | - Eric C. Rouchka
- KBRIN Bioinformatics Core, University of Louisville, Louisville, KY, USA
- Department of Computer Science and Engineering, J.B. Speed School of Engineering, University of Louisville, Louisville, KY, USA
| | - Irina A. Kirpich
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
- Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Matthew C. Cave
- UofL Superfund Research Center, University of Louisville, Louisville, KY, USA
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
- Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA
- Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA
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Brandner JM, Zorn-Kruppa M, Yoshida T, Moll I, Beck LA, De Benedetto A. Epidermal tight junctions in health and disease. Tissue Barriers 2015; 3:e974451. [PMID: 25838981 DOI: 10.4161/21688370.2014.974451] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 10/04/2014] [Indexed: 01/21/2023] Open
Abstract
The skin, the largest organ of the body, is an essential barrier that under homeostatic conditions efficiently protects and/or minimizes damage from both environmental (e.g. microorganisms, physical trauma, ultraviolet radiation) and endogenous (e.g., cancers, inflammation) factors. This formidable barrier function resides mainly in the epidermis, a dynamic, highly-stratified epithelium. The epidermis has 2 major barrier structures: stratum corneum, the outmost layer and tight junctions, intercellular junctions that seal adjacent keratinocytes in the stratum granulosum, found below the stratum corneum. In recent years there have been significant advances in our understanding of tight junction function, composition and regulation. Herein we review what is known about tight junctions in healthy skin and keratinocyte culture systems and highlight the dynamic crosstalk observed between tight junctions and the cutaneous immune system. Finally we discuss the preliminary observations suggesting that tight junction function or protein expression may be relevant for the pathogenesis of a number of common cutaneous inflammatory and neoplastic conditions.
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Key Words
- AD, atopic dermatitis
- AMP, antimicrobial peptides
- Cldn, claudin
- DC, dendritic cells
- FLG, filaggrin
- JAM, junctional adhesion molecule
- LC, Langerhans cells
- MM, malignant melanoma
- PRR, pattern recognition receptor
- PS, psoriasis
- SCC, squamous cell carcinoma; SC, stratum corneum
- SG, stratum granulosum
- SNP, single nucleotide polymorphism
- TER, TransEpithelial Electrical Resistance
- TJ, tight junction
- TLR, Toll-like receptor
- Th, T helper
- ZO-1, zonula occludens 1
- claudins
- skin barrier
- skin immune system
- skin innate barrier
- tight junction
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Affiliation(s)
- J M Brandner
- Department of Dermatology and Venereology; University Hospital Hamburg-Eppendorf ; Hamburg, Germany
| | - M Zorn-Kruppa
- Department of Dermatology and Venereology; University Hospital Hamburg-Eppendorf ; Hamburg, Germany
| | - T Yoshida
- Department of Dermatology; University of Rochester Medical Center ; Rochester, NY USA
| | - I Moll
- Department of Dermatology and Venereology; University Hospital Hamburg-Eppendorf ; Hamburg, Germany
| | - L A Beck
- Department of Dermatology; University of Rochester Medical Center ; Rochester, NY USA
| | - A De Benedetto
- Department of Dermatology; University of Rochester Medical Center ; Rochester, NY USA
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