Effects of Xenoestrogens on T Lymphocytes: Modulation of bcl-2 p53, Apoptosis

International Journal of Molecular Sciences

Kenneth Ndebele¹  Paul B. Tchounwou¹ 

[1]Molecular Toxicology Research Laboratory, JacksonState University, NIH-Center for  Environmental Health, School of Science and Technology, 1400 Lynch Street, Box 18540, Jackson, Mississippi 39217,USA.

关键词: Xenoestrogens;    coumestrol;    bisphenol A;    DDT;    TCDD;    T lymphocytes;    cell cycle;   

DOI  :  10.3390/i4020045

来源: mdpi

【 摘 要 】

Endogenous estrogens have significant immunomodulatory effects characterized as suppression of cell mediated immunity and stimulation of humoral immunity. Xenoestrogens are environmental estrogens that have endocrine impact, acting as estrogen agonists and antagonists but whose immune effects are not well characterized. Using CD4⁺ Jurkat T cells as a model, the effects of representative xenoestrogens on T proliferation, cell cycle, and apoptosis were examined. Coumestrol (CM), a phytoestrogen, and tetrachlorodioxin (TCDD) in concentrations of 10^-4 to 10^-6M significantly inhibited Jurkat T cell lymphoproliferation, whereas bisphenol A (BPA) and DDT had minimal effect, but did antagonize 17-β-estrtadiol induced effects. Xenoestrogens, especially CM, produced accumulation of Jurkat T cells in G₂/M phase, and subsequently induced apoptosis, particularly CM (% apoptotic cells = 30 ± 12 vs. control = 5 ± 2). These changes were associated with DNA fragmentation. BPA and DDT also induced DNA fragmentation but not significant DNA hypoploidy. Xenoestrogen – CM, BPA, DDT, and TCDD - exposure suppressed bcl-2 protein and mRNA transcript levels but augmented p53 protein and mRNA transcripts. Human purified peripheral blood lymphocytes responded with similar significant cell cycle changes (G₀/G₁ exodus and G₂/M accumulation) for CM, BPA, and DDT exposure. These preliminary data, taken together, suggest that xenoestrogens have direct, compound-specific T lymphocyte effects that enhance our understanding of environmental modulation of immune and autoimmune responses.

【 授权许可】

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