Document Type

Thesis

Date of Degree Completion

Fall 2016

Degree Name

Master of Science (MS)

Department

Biology

Committee Chair

April K. Binder

Second Committee Member

Lucinda Carnell

Third Committee Member

Holly Pinkart

Abstract

The ovary is a dynamic organ that responds to many hormonal signals. When these hormonal signals are disrupted, ovarian dysfunction can occur. One such example is Polycystic Ovarian Syndrome (PCOS). PCOS patients suffer from high levels of testosterone. Excess testosterone may misregulate genes in the ovary and disrupt ovarian function. The Claudin (Cldn) 3 and Cldn11 genes have been shown to be regulated by androgens in the testis, while studies in ovarian cancer cells suggests a coregulatory mechanism for the expressions of Cldn3 and Cldn4 in the ovary. The objective of this study was to characterize the hormonal regulation of Claudin gene expression in the ovary. The ovaries of estrogen receptor alpha knockout (αERKO) mice have high serum testosterone concentrations, therefore Claudin expression was measured in these ovaries. Experiments were conducted using Quantitative Real Time PCR (QRT-PCR) to monitor the expression of Cldn3, 4, and 11 in wild-type (WT) and αERKO mouse ovaries. These experiments indicated that Cldn3, 4, and 11 were more highly expressed in αERKO mice than their wild-type counterparts (p < 0.05, n = 5). Further experiments characterized Claudin expression in the ovaries of mice treated with Dihydrotestosterone (DHT) for 90 days which serve as a common mouse model of PCOS. DHT treated mice were found to express Cldn3 and Cldn11 significantly higher than control mice. Cldn4 expression decreased in DHT treated mice when compared to the controls (p < 0.05, n = 4 for control and DHT groups). These findings indicated that Cldn3 and Cldn11 are upregulated by testosterone in the ovary. The data also indicates Cldn4 is regulated via different mechanisms than the other Claudin genes in the mouse ovary. DHT reduces expression of Cldn4, while increases are observed in the absence of ERα. Claudin expression was also evaluated in the ovaries of mice that were treated with testosterone propionate (TP) for three or six days. No expression of Cldn3 or Cldn11 was found, however Cldn4 steadily increased in conjunction with the duration of the testosterone propionate treatment. Western blot analysis for the presence of CLDN3 in the ovaries of control and TP treated mice yielded no detectable signal for either group. Studies done in cell lines found that CLDN4 expression decreased when BG-1 ovarian epithelial cells were treated with testosterone. These findings provide a first consider the regulation of the Claudin genes in the ovary, while providing a basis for future research to explore how they may contribute to PCOS.

Language

English

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