Campus Units

Animal Science

Document Type

Article

Publication Version

Published Version

Publication Date

4-1-2011

Journal or Book Title

Biology of Reproduction

Volume

84

Issue

4

First Page

743

Last Page

751

DOI

10.1095/biolreprod.110.087650

Abstract

4-Vinylcyclohexene diepoxide (VCD), an occupational chemical that specifically destroys primordial and small primary follicles in the ovaries of rats and mice, is thought to target an oocyte-expressed tyrosine kinase receptor, Kit. This study compared the temporal effect of VCD on protein distribution of KIT and its downstream PIK3-activated proteins, AKT and FOXO3. Postnatal Day 4 Fischer 344 rat ovaries were cultured in control media ± VCD (30 μM) for 2–8 days (d2–d8). KIT, AKT, phosphorylated AKT, FOXO3, and pFOXO3 protein levels were assessed by Western blotting and/or immunofluorescence staining with confocal microscopy. Phosphorylated AKT was decreased (P < 0.05) in oocyte nuclei in primordial (39% decrease) and small primary (37% decrease) follicles within 2 days of VCD exposure. After d4, VCD reduced (P < 0.05) oocyte staining for KIT (primordial, 44% decrease; small primary, 39% decrease) and FOXO3 (primordial, 40% decrease; small primary, 36% decrease) protein. Total AKT and pFOXO3 were not affected by VCD at any time. Akt1 mRNA, as measured by quantitative RT-PCR, was reduced (P < 0.05) by 23% on d4 of VCD exposure, but returned to control levels on d6 and d8. VCD exposure reduced Foxo3amRNA by 26% on d6 (P < 0.05) and by 23% on d8 (P < 0.1). These results demonstrate that the earliest observed effect of VCD is an inhibition of phosphorylation and nuclear localization of AKT in the oocyte of primordial and small primary follicles. This event is followed by reductions in KIT and FOXO3 protein subcellular distribution prior to changes in mRNA. Thus, these findings further support that VCD induces ovotoxicity by directly targeting the oocyte through posttranslational inhibition of KIT-mediated signaling components.

Comments

This article is published as Keating, Aileen F., Shannon M. Fernandez, Connie J. Mark-Kappeler, Nivedita Sen, I. Glenn Sipes, and Patricia B. Hoyer. "Inhibition of PIK3 signaling pathway members by the ovotoxicant 4-vinylcyclohexene diepoxide in rats." Biology of reproduction 84, no. 4 (2011): 743-751. doi: 10.1095/biolreprod.110.087650.

Creative Commons License

Creative Commons Attribution-Noncommercial 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 License

Copyright Owner

Society for the Study of Reproduction, Inc.

Language

en

File Format

application/pdf

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