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Jedeon K.,Institute National Of La Sante Et Of La Recherche Medicale Umrs 1138 | Jedeon K.,University of Paris Descartes | Jedeon K.,University Pierre and Marie Curie | Jedeon K.,University Paris Diderot | And 20 more authors.
Endocrinology | Year: 2014

Bisphenol A (BPA) is a widespread endocrine disrupting chemical (EDC) strongly suspected to have adverse health effects.Numeroustissuesandcells are affected by BPA,andweshowedrecently that BPA targets include ameloblasts and enamel. We therefore investigated the effects of BPA on ameloblasts and the possible involvement of the estrogen signaling pathway. Rats were exposed daily to low-dose BPA, and developed enamel hypomineralization similar to human molar incisor hypomineralization (MIH). BPA increased ameloblast proliferation in vivo and in vitro. The proliferation of the rat dental epithelial cell line HAT-7 was also increased by estrogen (E2). Ameloblasts express ERα but not ERβ both in vivo and in vitro. The ER antagonist ICI 182,780 was used to inactivate ERα and abolished the effects of E2 on cell proliferation and transcription, but only partially reduced the effects of BPA. In conclusion, we show, for the first time, that: 1) BPA has ER-dependent and ER-independent effects on ameloblast proliferation and gene transcription; 2) the estrogen signaling pathway is involved in tooth development and the enamel mineralization process; and 3) BPA impacts preferentially amelogenesis in male rats. These results are consistent with the steroid hormones having effect on ameloblasts, raising the issues of the hormonal influence on amelogenesis and possible differences in enamel quality between sexes. Copyright © 2014 by the Endocrine Society.

Marinozzi M.C.,Institute National Of La Sante Et Of La Recherche Medicale Umrs 1138 | Vergoz L.,Institute National Of La Sante Et Of La Recherche Medicale Umrs 1138 | Rybkine T.,Institute National Of La Sante Et Of La Recherche Medicale Umrs 1138 | Ngo S.,Assistance Publique Hopitaux de Paris | And 12 more authors.
Journal of the American Society of Nephrology : JASN | Year: 2014

Atypical hemolytic uremic syndrome (aHUS) is a genetic ultrarare renal disease associated with overactivation of the alternative pathway of complement. Four gain-of-function mutations that form a hyperactive or deregulated C3 convertase have been identified in Factor B (FB) ligand binding sites. Here, we studied the functional consequences of 10 FB genetic changes recently identified from different aHUS cohorts. Using several tests for alternative C3 and C5 convertase formation and regulation, we identified two gain-of-function and potentially disease-relevant mutations that formed either an overactive convertase (M433I) or a convertase resistant to decay by FH (K298Q). One mutation (R178Q) produced a partially cleaved protein with no ligand binding or functional activity. Seven genetic changes led to near-normal or only slightly reduced ligand binding and functional activity compared with the most common polymorphism at position 7, R7. Notably, none of the algorithms used to predict the disease relevance of FB mutations agreed completely with the experimental data, suggesting that in silico approaches should be undertaken with caution. These data, combined with previously published results, suggest that 9 of 15 FB genetic changes identified in patients with aHUS are unrelated to disease pathogenesis. This study highlights that functional assessment of identified nucleotide changes in FB is mandatory to confirm disease association. Copyright © 2014 by the American Society of Nephrology.

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