Characterization of Integrin Expression in the Mouse Ovary1

Abstract

Integrin alpha:beta heterodimers mediate cell contacts to the extracellular matrix and initiate intracellular signaling cascades in response to a variety of factors. Integrins interact with many determinants of cellular phenotypes and play roles in controlling the development, structural integrity, and function of every type of tissue. Despite their importance, little is known about the regulation of integrin subunits in the mammalian ovary and how they function in folliculogenesis. To determine their relevance to ovarian physiology, we have studied the expression of integrin subunit mRNAs by Northern blot analysis and in situ hybridization in ovaries of wild-type, growth differentiation factor 9 (Gdf 9) knockout, FSHbeta (Fshb) knockout, and inhibin alpha (Inha) knockout mice. Integrin alpha6 mRNA is expressed in oocytes and granulosa cells of single-layer follicles and in oocytes and theca cells of multilayer follicles. Integrin alpha6 is highly expressed in Gdf 9 knockout ovaries, which are enriched in oocytes and primary (single layer) follicles because of a block at this stage of follicular development. Integrin alpha(v) mRNA is most highly expressed in the granulosa cells of multilayer growing follicles, and therefore only low levels of expression are detectable in the Gdf 9 knockout ovaries. Integrin beta1 mRNA exhibits a broad expression pattern in ovaries, including oocytes, granulosa cells, theca cells, and corpora lutea. Integrin beta3 mRNA is expressed in theca and interstitial cells and is upregulated in corpora lutea. It is nearly undetectable in ovaries of Fshb knockout mice, which develop preantral follicles but have no luteal cells. Integrin beta5 mRNA is predominantly expressed in granulosa cells of multilayer follicles. It is expressed at high levels in the Fshb knockout mice and in a compartmentalized manner in the granulosa cell/Sertoli cell tumors that develop in the Inha knockout mice. Specific integrins are associated with ovarian cellular phenotypes in mice, which raises intriguing possibilities as to integrin functions in oocyte competence, follicular development, luteinization, and granulosa cell proliferation.

The Roles of THY1 and Integrin Beta3 in Cell Adhesion During Theca Cell Layer Formation and the Effect of Follicle-Stimulating Hormone on THY1 and Integrin Beta3 Localization in Mouse Ovarian Follicles

“…With regard to integrin beta3 in mammalian ovary, few reports have appeared. Burns et al [30] reported that integrin beta3 mRNA was expressed in theca and interstitial cells in mouse ovary, in agreement with our data in the present study. Coincubation with blocking antibody against integrin alpha5 beta3 increased apoptosis and prevented migration in human luteinized granulosa cells grown on fibronectin, suggesting that integrin beta3 might promote survival and migration of granulosa cells [41].…”

“…An interaction between integrin beta3 and THY1 has been reported to play a role in cell adhesion [27,28]. The mRNA expression of various integrins has been reported in mouse ovaries, and integrin beta3 was found to be expressed only in the theca cell layers in follicles [30]. However, a relationship between THY1 and integrin beta3 function has not been shown in ovaries.…”

The in vitro regulation of ovarian follicle development using alginate-extracellular matrix gels

“…In addition to maintaining the cell-cell connections, cells within three-dimensional environments utilize different integrins and form distinct adhesions with the ECM compared to two-dimensional systems [13], which can affect both cellular organization and tissue function [14]. During follicle development, ECM composition [15] and integrin expression [16] change; however, whether these changes are the result or cause of maturation has not been identified [17]. ECM composition is known to affect granulosa cell differentiation in vitro [18,19].…”

Expression Pattern of .ALPHA.v.BETA.3 and .ALPHA.v.BETA.5 Integrin mRNA in Mouse Fetal Gonads

“…integrin-deficient mice, demonstrated normal development and fertility [25,29]. We need to verify the localization of vitronectin in the fetal mouse gonads, although the gonadal cells may have another ligand that is recognized by αvβ5 integrin.…”

“…PCR consisted of an initial denaturing step of 2 min at 95 C; 33 cycles of 1 min at 95 C, 1 min at 54 C, and 1 min at 72 C for β3 integrin primers; 27 cycles of 1 min at 95 C, 1 min at 58 C, and 1 min at 72 C for β5 integrin primers; and 10 min at 72 C. The primer sequences for β3 integrin were: forward 5'-GTCACATTGGCA-CCGACAACC-3', and reverse 5'-CCACACTC-AAAAGTCCCGTTC-3', which were used to amplify a 556 bp fragment from the mouse β3 integrin cDNA. For β5 integrin, the primers were forward 5'-GGCTGCTGTCT-GCAAGGAG-3', and reverse 5'-TTCAAAGGATG-CCGTGTCC-3', which were used to amplify a 511 bp fragment from the mouse β5 integrin cDNA [25]. As an internal control, we used a housekeeping gene, Gapdh (forward 5'-TGAAGGTCGGTGT-CAACGGA-TTTGGC-3 and reverse 5'-CATGTAGGCCA-TGAGGTCCACC-3').…”