[Frontiers in Bioscience E3, 1401-1413, June 1, 2011]

Interactions of thyroid hormone and FSH in the regulation of rat granulosa cell apoptosis

Cheng Zhang1,2,3, Guoliang Xia1, Benjamin K. Tsang2, 3, 4

1State Key Laboratory for Agro-Biotechnology, College of Biological Science, China Agricultural University, Beijing 100193, Peoples' Republic of China, 2Reproductive Biology Unit, Departments of Cellular and Molecular Medicine, and Obstetrics & Gynaecology, University of Ottawa, Ottawa, Ontario, Canada K1Y 4E9. 3Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada, 4World Class University (WCU) Biomodulation Major, Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Materials
3.2. Rat granulosa cell isolation and culture
3.3. Protein extraction and western blot analysis
3.4. RNA extraction, cDNA synthesis, and real-time PCR analysis
3.5. TUNEL
3.6. Statistical analysis
4. Results
4.1. The effect of FSH and T3 on Fas and FasL protein and mRNA content
4.2. T3 significantly increased FSH-induced Xiap content In Vitro
4.3. T3 and FSH protected granulosa cells from ceramide-induced apoptosis
4.4. T3 enhanced FSH-induced up-regulation of granulosa cell P-Akt content
4.5. T3-FSH interaction increased granulosa cell P-Src content
4.6. Src & PI-3K/Akt pathway is involved the regulation of Fas, FasL and Xiap by FSH and T3
5. Discussion
6. Acknowledgment
7. References

1. ABSTRACT

Thyroid hormone (TH) is important for normal reproductive function. Our previous studies indicate that FSH increases preantral follicle growth in vitro, a response markedly enhanced by triiodothyronine (T3). However, the nature of this hormonal interaction is poorly understood. The objective of this study was to determine if and how T3 modulate FSH-induced expression and actions of granulosa cell intracellular survival and death intermediates. We investigated the possible involvement of Src and PI3K/Akt pathway in the regulation of granulosa cell survival. We demonstrated that, while ineffective alone (0.1-100 nM), T3 markedly enhanced FSH (100 ng/ml)-induced granulosa cell phospho-Src and phospho-Akt contents and Xiap expression in vitro. The effects of T3 were concentration-dependent, with maximal responses at 1.0 nM. FSH alone decreased Fas Ligand (FasL) content irrespective of the presence of T3. Co-treatment of cell with T3 and FSH decreased Fas content, although neither hormone alone elicited a significant response. Taken together, the present study demonstrates that T3 potentiates the cell survival action of FSH through Src- and PI3K-mediated Xiap up-regulation and decreased Fas and FasL expression.