Expression and cellular distribution of estrogen and progesterone receptors and the real-time proliferation of porcine cumulus cells

The processes of cellular growth, aging, and programmed cell death are involved in lifespan of ovarian granulosa cells during short-term IVC - Study based on animal model

The oogenesis and folliculogenesis are closely linked and occur simultaneously in the growing ovarian follicles. Biochemical and morphological changes in oocytes (OC) and surrounding granulosa cells (GCs) are highly complex and depend on many factors, including intercellular communication. GCs are cells with many functions, often crucial for the proper viability of the oocyte and subsequent positive fertilization. The purpose of this study was to analyze gene expression in porcine GCs, to define differentially expressed genes belongs to the "cell growth", "aging", "positive regulation of cell death", "apoptotic process", "regulation of cell death", "cell death" and "negative regulation of cell death" ontology groups during the short - term primary in vitro culture. Microarrays were employed to study the transcriptome contained in the total RNA of the cultured GCs. Ovaries were obtained after slaughter, from 40 gilts of swine aged 170 days. The cells were obtained through puncture of the ovaries, collection of follicular fluid, removal of the cumulus - oocyte complexes and centrifugation. The cells were then cultured in vitro. The RNA material was obtained before the culture was established (0h) and then after 48h, 96h and 144h of its course. From 182 differently expressed genes belonging to the these ontology groups, we have selected POSTN, FN1, FMOD, ITGB3, DCN, SERPINB2, SFRP2, IGFBP5, EMP1, and CCL2 which were upregulated, as well as DAPL1, ESR1, IHH, TGFBR3, PPARD, PDK4, TXNIP, IFIT3, CSRNP3, and TNFSF10 genes whose expression was downregulated during the time of in vitro culture of the GCs. The significance of the differential gene expression is to provide new information on the molecular aspects of in vitro granulosa cell culture.

Biological and physiological characteristics of human cumulus cells in adherent culture condition

Background

Cumulus cells, as oocyte nurse cells, provide a suitable microenvironment with growth factors and cellular interactions required for oocyte maturation. Thus, these cells may serve as a natural niche for in vitro studies of female germ cell development. Cumulus cells may help attain a better understanding of the causes of infertility in women and eventually improve the outcomes of cases that respond poorly to standard infertility treatment.

Objective

The aim of this study was to isolate, culture, and investigate the biological characteristics of human cumulus cells.

Materials and Methods

In this experimental study, cumulus cells were isolated, cultured, and characterized using reverse transcription-polymerase chain reaction analyses of specific genes including FOXL2, CYP19A1, FSHR, AMHR, and LHR. The presence of vimentin, a structural protein, was examined via immunofluorescent staining. Moreover, levels of anti-mullerian hormone (AMH) and progesterone secretion by cumulus cells were measured with ELISA after 2, 4, 12, 24, and 48 hr of culture.

Results

In adherent culture, human cumulus cells expressed specific genes and markers as well as secreted AMH and progesterone into the medium.

Conclusion

Cumulus cells secrete AMH and progesterone in an adherent culture and might be applicable for in vitro maturation (IVM) and in vitro gametogenesis (IVG) studies.

Characteristic of factors influencing the proper course of folliculogenesis in mammals

Folliculogenesis is the process of ovarian follicle formation,, taking presence during foetal period. During the follicular development, oogoniums undergo meiosis and oocytes are formed. In the ovaries of new born sows, primary and secondary follicles are present and, 90 days after birth, tertiary follicles appear. During development in the ovarian follicles growth of granulosa cells and differentiation of the thecal cells can be observed. A cavity filled with follicular fluid appears. Granulosa cells are divided into: mural cells and corona radiata, which together with the oocyte form the cumulus oophorus. Corona radiata cells, mural layers and oolemma contact each other by a network of gap junctions. Secreted from the pituitary gland, FSH and LH gonadotropin hormones act on receptors located in granular and follicular cells. In the postnatal life tertiary follicles and Graafian follicles are formed. When the follicle reaches a diameter of 1 mm, further growth depends on the secretion of gonadotropins. Mature ovarian follicles produce: progestins, androgens and oestrogens. The growth, differentiation and steroidogenic activity of ovarian follicles, in addition to FSH and LH, is also affected by prolactin, oxytocin, steroid and protein hormones, numerous proteins from the cytokine and interleukin family, metabolic hormones like insulin, glucocorticoids, leptin, thyroid hormones and growth hormones. Despite numerous studies, many processes related to folliculogenesis have not been discovered Learning the mechanisms regulating reproductive processes would allow to easily distinguish pathological processes and discover more and more genes and mechanisms of their expression in cells that build ovarian follicles.

Time- and Dose-Dependent Effects of 17 Beta-Estradiol on Short-Term, Real-Time Proliferation and Gene Expression in Porcine Granulosa Cells

The key mechanisms responsible for achievement of full reproductive and developmental capability in mammals are the differentiation and transformation of granulosa cells (GCs) during folliculogenesis, oogenesis, and oocyte maturation. Although the role of 17 beta-estradiol (E2) in ovarian activity is widely known, its effect on proliferative capacity, gap junction connection (GJC) formation, and GCs-luteal cells transformation requires further research. Therefore, the goal of this study was to assess the real-time proliferative activity of porcine GCs in vitro in relation to connexin (Cx), luteinizing hormone receptor (LHR), follicle stimulating hormone receptor (FSHR), and aromatase (CYP19A1) expression during short-term (168 h) primary culture. The cultured GCs were exposed to acute (at 96 h of culture) and/or prolonged (between 0 and 168 h of culture) administration of 1.8 and 3.6 μM E2. The relative abundance of Cx36, Cx37, Cx40, Cx43, LHR, FSHR, and CYP19A1 mRNA was measured. We conclude that the proliferation capability of GCs in vitro is substantially associated with expression of Cxs, LHR, FSHR, and CYP19A1. Furthermore, the GC-luteal cell transformation in vitro may be significantly accompanied by the proliferative activity of GCs in pigs.

Influence of Estradiol-17beta on Progesterone and Estrogen Receptor mRNA Expression in Porcine Follicular Granulosa Cells during Short-Term, In Vitro Real-Time Cell Proliferation

Progesterone (P4) and estradiol (E2) play a significant role in mammalian reproduction. Our study demonstrated that separated porcine cumulus cells (CCs) and/or granulosa cells (GCs) might proliferate in vitro during short-term, real-time primary culture. The GCs were analyzed according to gene expression of the progesterone receptor (nuclear form) (pgr), progesterone receptor membrane component 1 (pgrmc1), and estrogen-related receptor beta 3 (esrrb3) in relation to two housekeeping genes: actb and pbgd. GCs were cultivated in medium with the E2. Both pgr/actb and pgr/pbgd revealed higher expression between 24 and 168 h of IVC of prolonged E2 treatment and at 48 h of IVC after acute E2 administration. The pgrmc1/actb and pgrmc1/pbgd displayed increased expression after prolonged E2 treatment between 24 and 120 h of IVC. The highest level of esrrb3/actb at 120 and 144 h, as well as esrrb3/pbgd at 120 h, in untreated controls as compared to the hormone-stimulated group, was observed. We suggest that E2 significantly influences the upregulation of pgr, pgrmc1, and esrrb3 expression in porcine GCs during real-time cell proliferation. Since esrrb3 expression is stimulated by E2 in both an acute and prolonged manner, estradiol may be recognized as a potential estrogen receptor agonist in GCs.