Proinflammatory properties of coplanar PCBs: In vitro and in vivo evidence

Bernhard Hennig, Purushothaman Meerarani, Rabih Slim, Michal Toborek, Alan Daugherty, Allen E. Silverstone, Larry W. Robertson

Research output: Contribution to journalArticlepeer-review

219 Scopus citations

Abstract

So-called coplanar polychlorinated biphenyls (PCBs), as well as other environmental contaminants that are aryl hydrocarbon receptor (AhR) agonists, may compromise the normal functions of vascular endothelial cells by activating oxidative stress-sensitive signaling pathways and subsequent proinflammatory events critical in the pathology of atherosclerosis and cardiovascular disease. To test this hypothesis, porcine endothelial cells were exposed to PCB 153 and to three coplanar PCBs (PCB 77, PCB 126, or PCB 169). In contrast to PCB 153, which is not a ligand for the Ah receptor (AhR), all coplanar PCBs disrupted endothelial barrier function. All coplanar PCBs increased expression of the CYP1A1 gene, oxidative stress (DCF fluorescence), and the DNA-binding activity of nuclear factor κB (NF-κB). PCB-induced oxidative stress was concentration-dependent, with PCB 126 exhibiting a maximal response at the lowest concentration (0.5 μM) tested. The increase in NF-κB-dependent transcriptional activity was confirmed in endothelial cells by a luciferase reporter gene assay. In contrast to PCB 153, coplanar PCBs that are AhR ligands increased endothelial production of interleukin-6. At 3.4 μM, expression of the adhesion molecule VCAM-1 was most sensitive to PCB 77 and 169. We also provide in vivo evidence, suggesting that binding to the AhR is critical for the proinflammatory properties of PCBs. Twenty hours after a single administration of PCB 77, VCAM-1 expression was increased only in wild-type mice, while mice lacking the AhR gene showed no increased staining for VCAM-1. These data provide evidence that coplanar PCBs, agonists for the AhR, and inducers of cytochrome P450 1A1, produce oxidative stress and an inflammatory response in vascular endothelial cells. An intact AhR may be necessary for the observed PCB-induced responses. These findings suggest that activation of the AhR can be an underlying mechanism of atherosclerosis mediated by certain environmental contaminants.

Original languageEnglish
Pages (from-to)174-183
Number of pages10
JournalToxicology and Applied Pharmacology
Volume181
Issue number3
DOIs
StatePublished - 2002

Bibliographical note

Funding Information:
We thank Drs. P. Fernandez-Salguero and F. Gonzalez (NCI, Bethesda, MD) for providing the initial founder mice, and Haley Elam for the immunocytochemical analysis of VCAM-1. This study was supported in part by grants from NIEHS (P42 ES 07380, ES 07216), and the Kentucky Agricultural Experimental Station. The content of this paper is solely the responsibility of authors and not necessarily represents the official view of the funding agencies.

Funding

We thank Drs. P. Fernandez-Salguero and F. Gonzalez (NCI, Bethesda, MD) for providing the initial founder mice, and Haley Elam for the immunocytochemical analysis of VCAM-1. This study was supported in part by grants from NIEHS (P42 ES 07380, ES 07216), and the Kentucky Agricultural Experimental Station. The content of this paper is solely the responsibility of authors and not necessarily represents the official view of the funding agencies.

FundersFunder number
National Institute of Environmental Health Sciences (NIEHS)ES 07216, P42ES007380
Kentucky Agricultural Experiment Station

    Keywords

    • Aryl hydrocarbon receptor
    • Atherosclerosis
    • Disease
    • Endothelial cells
    • Environmental contaminants
    • Oxidative stress
    • Polychlorinated biphenyls

    ASJC Scopus subject areas

    • Toxicology
    • Pharmacology

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