Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression

Abstract

The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (nZ11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; nZ6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; nZ5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P!0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function.

Involvement of miRNAs in ovarian follicular and luteal development

“…Two key developments during the last 12 years have dramatically increased knowledge of the molecular control of follicular and luteal development. One is the advent and application of genomic technologies to study ovarian function leading to the identification of hundreds of new genes putatively involved in ovarian processes in different species (Espey & Richards 2002, Evans et al 2004, Agca et al 2006, Hamel et al 2008, Bogan et al 2009). The second major development has been the discovery and characterisation of animal microRNAs (miRNAs) as key global post-transcriptional regulators of tissue growth and differentiation both in health and disease (Ambros 2004, Croce 2009, Sayed & Abdellatif 2011.…”

The influence of adiponectin on the transcriptomic profile of porcine luteal cells

“…Of them, 186 were up-regulated, whereas 203 were down-regulated. Other microarray analyses of the ovarian tissues conducted by Caetano et al (2004) and Agca et al (2006) indicated both quantitative and qualitative variations in the global gene expression. Agca et al (2006) studied differences in the global gene expression between ovarian follicles before and after luteinization (43 up-regulated and 107 down-regulated genes).…”

“…Other microarray analyses of the ovarian tissues conducted by Caetano et al (2004) and Agca et al (2006) indicated both quantitative and qualitative variations in the global gene expression. Agca et al (2006) studied differences in the global gene expression between ovarian follicles before and after luteinization (43 up-regulated and 107 down-regulated genes). Caetano et al (2004) observed differences in the various ovarian tissues gene expression during days 2-6 of the luteal phase between gilts line with the high-average oocyte production and randomly selected control line.…”

A pilot study on transcriptome data analysis of folliculogenesis in pigs

“…These analyses have already been used for the discovery of genes involved in pig female reproductive performances: Caetano et al (2004) studied whole follicle transcriptome from two pig lines differing in their ovulation rate, Agca et al (2006) focused on early luteinisation process and Whitworth et al (2005) studied early embryonic development. a These authors have contributed equally to this work.…”