Genes involved in hormone metabolism and cellular response in human ovarian granulosa cells.

Endocrinal interactions are one of the most crucial regulatory mechanisms that maintain the state of homeostasis in humans. Processes such as oogenesis, folliculogenesis, menstruation and pregnancy remain under hormonal control. A key role in folliculogenesis is played by granulosa cells. Moreover, granulosa cells take part in corpus luteum formation after ovulation. Because of that, it is important to understand the ways in which the granulosa cells, associated with those processes, respond to hormonal stimulus. In the present study, a transcriptomic analysis of human granulosa cells (GCs) was carried out with the use of expression microarrays. The results were validated by RT-qPCR. The total RNA was isolated after 1st, 7th, 15th and 30th days of long-term primary cultures. The main focus of this work was placed on the genes belonging to "Response to estradiol", "Response to follicle-stimulating-hormone", "Cellular response to hormone stimulus", "Cellular hormone metabolic process" and "Hormone biosynthetic process" gene ontology groups. These groups of genes have been associated with GC hormone metabolism and cellular response to hormones. Eighty genes belonging to these groups were identified. Those that were members of more than one of the analyzed gene ontology groups, or exhibited unique expression patterns, were selected for further analysis. All of the selected genes were described, with their expression patterns detailed. In this manuscript, two gene expression patterns have been described. The first one showed large downregulation of genes in the later stages of culture, with the second one presenting upregulation of expression after day 1 of IVC. The present research was focused on six genes found to be the most important for steroidogenesis: STAR, POR, CYP11A1, ADM, GCLC, IL1B, as well as three genes of higher expression at the later stages of long-term in vitro culture: NR2F2, BMP4, COL1A1. The main goal of the presented study was to select genes involved in response to hormonal stimulus and hormone metabolism in GC long-term in vitro culture.

Transcriptomic profile of cell cycle progression genes in human ovarian granulosa cells.

The ovarian granulosa cells (GCs) that form the structure of follicle undergo substantial modification during the various stages of human folliculogenesis. These modifications include morphological changes, accompanied by differential expression of genes, encoding proteins which are mainly involved in cell growth, proliferation and differentiation. Recent data bring a new insight into the aspects of GCs' stem-like specificity and plasticity, enabling their prolonged proliferation and differentiation into other cell types. This manuscript focuses attention on emerging alterations during GC cell cycle - a series of biochemical and biophysical changes within the cell. Human GCs were collected from follicles of women set to undergo intracytoplasmic sperm injection procedure, as a part of remnant follicular fluid. The cells were primarily cultured for 30 days. Throughout this time, we observed the prominent change in cell morphology from epithelial-like to fibroblast-like, suggesting differentiation to other cell types. Additionally, at days 1, 7, 15 and 30, the RNA was isolated for molecular assays. Using Affymetrix® Human Genome U219 Array, we found 2579 human transcripts that were differentially expressed in GCs. From these genes, we extracted 582 Gene Ontology Biological Process (GO BP) Terms and 45 KEGG pathways, among which we investigated transcripts belonging to four GO BPs associated with cell proliferation: "cell cycle phase transition", "G1/S phase transition", G2/M phase transition" and "cell cycle checkpoint". Microarray results were validated by RT-qPCR. Increased expression of all the genes studied indicated that increase in GC proliferation during long-term in vitro culture is orchestrated by the up-regulation of genes related to cell cycle control. Furthermore, observed changes in cell morphology may be regulated by a presented set of genes, leading to the induction of pathways specific for stemness plasticity and transdifferentiation in vitro.

Enzyme linked receptor protein signaling pathway is one of the ontology groups that are highly up-regulated in porcine oocytes before in vitro maturation.

Before being able to fully participate in the processes associated with its function as a female gamete, the oocyte needs to undergo a range of changes to achieve its mature form. These morphological, biochemical and metabolomic processes are induced by the somatic tissues surrounding the oocyte, through the expression of specific transcription and growth factors. The maturation of the oocyte is highly important for the proceedings that lead to successful fertilization, early embryonic development and implantation. Domestic pigs were used as models for our study, with the cumulus-oocyte complexes obtained from the ovaries that were recovered at slaughter. After shedding of the cumulus, oocytes were assessed with BCB test, with the viable ones chosen to undergo in vitro maturation. With the use of expression microarrays, we analyzed gene expression before and after IVM and detected major changes in both genes that were proven to be associated with oocyte maturation before (FOS, VEGFA, CHRDL1, TGFBR3, FST, INSR, ID1, TXNIP, SMAD4, MAP3K1, EIF2AK3 and KIT) and genes not previously linked with reproduction associated processes (MYO1E, PHIP, KLF10 and SHOC2). All the genes were briefly described, with consideration of possible involvement of the newly discovered elements of the transcriptome in the process of oocyte maturation.

Expression of cell mitotic progression proteins and keratinocyte markers in porcine buccal pouch mucosal cells during short-term, real-time primary culture.

The porcine model is often used in clinical trials. The pig has many fundamental anatomic, physiological and nutritional similarities to humans. Additionally, the European Medicines Agency (EMA) demands the use large animals in clinical studies. Oral mucosa has received special attention due to its regenerative properties. Oral tissue is composed of several types of cells including fibroblasts and keratinocytes. The porcine oral mucosa/buccal pouch mucosa has a cellular structure with defined proliferation and differentiated capability. In this study, we investigated the expression pattern of porcine buccal pouch mucosal cell proliferation and differentiation markers such as Ki-67, proliferating cell nuclear antigen (PCNA), and involucrin. We observed a clear monolayer culture of spindle-shaped, porcine buccal pouch mucosal cells during 168 h of real-time in vitro culture. The RTCA assays revealed parametric and progressive increases in proliferation after 72 h of IVC. We found an altered proliferation index (PI) in the replicated groups of experiments except through the 144-168 h proliferation period. The RT-qPCR results demonstrated a significant increase in Ki-67 and PCNA expression after 48, 120, and 168 h of IVC as compared to other culture periods (P<0.001). The involucrin mRNA displayed increased expression after 168 h of IVC as compared to other periods. We observed a lack of PCR product at 24 h in the case of Ki-67 and both before IVC (0h) and after 24 h of IVC for PCNA mRNA. When we analyzed the three transcripts together, we found the highest expression of involucrin during each of the culture periods. It has been suggested that Ki-67, PCNA, and involucrin may be successfully used as markers of porcine buccal pouch mucosal cell proliferation and differentiation capability in vitro.

The origin, in vitro differentiation, and stemness specificity of progenitor cells.

Since the successful collection of the first progenitor stem cells (SCs), there has been an increased interest in these cells as a model for undiscovered and unlimited potential of differentiation and development. Additionally, it was shown that SC populations display an ability to form pluripotent and/or totipotent cell populations. It was found that human ovarian granulosa cells (GCs) maintain a large capacity for differentiation into several other cell lineages, such as chondrogenic, osteogenic, neurogenic, and adipogenic, particularly during long-term, in vitro culture. In these cases, the specific media supplements that promote various pathways of differentiation, such as leukemia-inhibiting factor (LIF) and/or FSH, are well recognized. However, these are only some examples of the differentiation possibilities of human SCs in vitro and other pathways still require further investigation. Many SC populations, which are directed to differentiate into specific cell types, are also successfully used in several human disease therapies, e.g. leukemia. Moreover, SCs are used for tissue scaffold construction in patients with respiratory and cardiovascular diseases. In this review, the most recent knowledge about the in vitro growth and differentiation capacity of SCs is presented. Furthermore, we discuss the possible worldwide application of SCs in advanced cell and tissue bioengineering. In conclusion, it is suggested that, in the future, SCs will be a basic strategy in human therapy, and their use will open new gates in regenerative and reconstructive medicine in the 21st century.

Molecular basis of growth, proliferation, and differentiation of mammalian follicular granulosa cells.

For normal folliculogenesis and oogenesis to occur many intrinsic and extrinsic factors are needed, i.e. positive feedback of hormone secretion and local ovarian-follicular growth factors distribution. During follicle formation, granulosa cells (GCs) change their morphology and physiological properties. The factors needed for GCs to differentiate within each layer are transforming growth factor beta (TGFB) and insulin-like growth factor (IGF), as well as the activation and modification of biochemical pathways involved in folliculogenesis. Physiological alterations occur when GC genes are characterized by several differences in their gene expression profile. Studies in recent years indicate a variety of processes involved in follicle morphology and biochemical remodeling during growth and development. It was demonstrated that IGFs play a central role in the differentiation of GCs both in vivo and in vitro. Moreover, the primary role of FSH and LH in the formation of the ovarian follicle, was also described. Our review article characterizes the most important pathways involved in the differentiation of GCs and the effect of various factors on gene expression in GCs during folliculogenesis.

The biomedical aspects of oral mucosal epithelial cell culture in mammals.

In recent years, there has been a growing interest in epithelial cell tissue culture, particularly oral mucosa and its application utilizing in vitro cell culture in medicine. This involves tests using animal models to better understand oral mucosa function, and the differences in its construction in various animal models. The use of buccal pouch mucosal cell culture provides insight into the processes of trans mucosal transport and regeneration of the oral epithelium. The processes associated with epithelium regeneration is the base for stem cell research and/or oral cancer investigation. These artificially cultured tissue equivalents are used in transplant surgery for the treatment of a variety of tissue dysfunctions, i.e. eye, esophagus, or urethra. In this review, the most recent results from studies carried out on in animal models, which may be applied in areas such as regenerative medicine and reconstructive surgery, were explored.

Microfluidic versus molecular assays - different approaches in assessing oocyte developmental competence.

In recent years, molecular techniques have brought about new solutions that focus on the developmental capacity of female oocytes and reproductive performance in the mammalian species. The developmental potency is the ability of oocytes to reach the MII stage following the long stages of folliculo- and oogenesis. The main proteins involved in this process belong to the connexin (Cx) family, which are responsible for the formation of gap junction (GJC) connections between the female gamete and surrounding somatic cells. The Cx are involved in bi-directional transport of small molecules and are therefore responsible for correct oocyte-somatic cell nutrition, proliferation, and differentiation. However, the application of certain molecular techniques often leads to destabilization or destruction of the materials of interest, such as cells or whole tissues. Therefore, the applications of microfluidic methods, which are non-invasive and quantitative, give new opportunities to further this area of biomedical research. Microfluidic research is based on real-time experiments that allow for control and/ or observation of the results during each step. The purpose of this review is to present both positive and negative aspects of molecular-microfluidic methods while describing the role of connexins in oocyte developmental capacity.

The differentiation of mammalian ovarian granulosa cells – living in the shadow of cellular developmental capacity.

The mammalian cumulus-oocyte complex (COCs) promotes oocyte growth and development during long stages of folliculogenesis and oogenesis. Before ovulation, the follicle is formed by a variety of fully differentiated cell populations; cumulus cells (CCs) that tightly surround the female gamete, granulosa cells (GCs) and theca cells (TCs) which build the internal and external mass of the follicular wall. It is well documented that CCs surrounding the oocyte are necessary for resumption of meiosis and full maturation of the gamete. However, the role of the granulosa cells in acquisition of MII stage and/or full fertilization ability is not yet entirely known. In this article, we present an overview of mammalian oocytes and their relationship to the surrounding cumulus and granulosa cells. We also describe the processes of GCs differentiation and developmental capacity. Finally, we describe several markers of mammalian GCs, which could be used for positive identification of isolated cells. The developmental capacity of oocytes and surrounding somatic cells – a “fingerprint” of folliculogenesis and oogenesis.

Epithelialization and stromalization of porcine follicular granulosa cells during real-time proliferation - a primary cell culture approach.

The process of oocyte growth and development takes place during long stages of folliculogenesis and oogenesis. This is accompanied by biochemical and morphological changes, occurring from the preantral to antral stages during ovarian follicle differentiation. It is well known that the process of follicle growth is associated with morphological modifications of theca (TCs) and granulosa cells (GCs). However, the relationship between proliferation and/or differentiation of porcine GCs during long-term in vitro culture requires further investigation. Moreover, the expression of cytokeratins and vimentin in porcine GCs, in relation to real-time cell proliferation, has yet to be explored. Utilizing confocal microscopy, we analyzed cytokeratin 18 (CK18), cytokeratin 8 + 18 + 19 (panCK), and vimentin (Vim) expression, as well as their protein distribution, within GCs isolated from slaughtered ovarian follicles. The cells were cultured for 168 h with protein expression and cell proliferation index analyzed at 24-h intervals. We found the highest expression of CK18, panCK, and Vim occurred at 120 h of in vitro culture (IVC) as compared with other experimental time intervals. All of the investigated proteins displayed cytoplasmic distribution. Analysis of real-time cell proliferation revealed an increased cell index after the first 24 h of IVC. Additionally, during each period between 24-168 h of IVC, a significant difference in the proliferation profile, expressed as the cell index, was also observed. We concluded that higher expression of vimentin at 120 h of in vitro proliferation might explain the culmination of the stromalization process associated with growth and domination of stromal cells in GC culture. Cytokeratin expression within GC cytoplasm confirms the presence of epithelial cells as well as epithelial-related GC development during IVC. Moreover, expression of both cytokeratins and vimentin during short-term culture suggests that the process of GC proliferation is also highly associated with porcine ovarian follicular granulosa cell differentiation in vitro.

Differential expression and distribution of cytokeratins and vimentin in buccal pouch mucosal cells during real-time cell proliferation: research based on a porcine model.

In recent years, buccal pouch oral mucosa cells were used as a source of potential biological grafting material in advanced tissue engineering. However, there are several limitations in the process of graft fabrication: donor and recipient patient availability as well as an incomplete knowledge of in vitro procedures related to tissue surgical recovery, in vitro cell culture (IVC) and/or tissue processing in "human somatic cell therapy." Therefore, the animal model for oral mucosa grafting is still recognized as a source for xenografts and a useful model for biomedical research. In this study, the porcine buccal pouch oral mucosa cells were used in analysis of the stromalization/epithelialization process during short-term, in vitro real-time cell proliferation. We evaluated cytokeratin 18 (CK18), cytokeratin 8 + 18 + 19 (panCK), and vimentin (Vim) expression as epithelial and stromal cell markers, respectively. The porcine buccal pouch oral mucosa cells were cultured in vitro for 168 h, and the protein expression/ distribution was analyzed every 24 h during real-time cell proliferation. In our analysis of protein expression using fluorescence intensity (FI), followed by confocal microscopic observations, we found the highest expression of CK18 occurred after 24 h of IVC, panCK after 72 h, and Vim after 48 h of IVC, as compared to other cultivation periods. We also found a substantial increase in Vim expression (3-4 fold) as compared to CK18 and panCK, and all of the investigated proteins were distributed in the cellular cytoplasm. The lag phase of cell proliferation occurred during the first 24 h of IVC, whereas the log phase was observed between 24 h-120 h of IVC. Throughout 7 days of IVC, statistically significant differences were found in Cell Index (CI) of the analyzed cells. Increased Vim expression in buccal pouch oral mucosa cells, as compared to CK18 and panCK, suggested that the stromal cells substantially predominated during in vitro cell cultivation. This may be a result of significant specificity of porcine oral mucosa cells isolated from the buccal pouch.

Association between expression of cumulus expansion markers and real-time proliferation of porcine follicular granulosa cells in a primary cell culture model.

Folliculogenesis is a compound process that involves both ovarian follicle growth and oocyte development, which is tightly attached to the follicular wall. During this process, cells that form the follicle structure undergo substantial morphological and molecular modifications that finally lead to differentiation and specialization of ovarian follicular cells. The differentiation of ovarian cells encompasses formation of follicle, which is composed of theca (TCs), mural granulosa (GCs), and cumulus cells (CCs). It was previously hypothesized that GCs and CCs represent undifferentiated and highly specialized follicular cells, respectively, which may have similar primordial cell origins. In this study, we investigated the expression pattern of cumulus expansion markers such as COX2, HAS2, PTX3, and TSG6 in porcine GCs during short-term, in vitro culture. We hypothesized that these genes may display an important function in GCs in relation to cellular real-time proliferation. The expression pattern of COX2, HAS2, PTX3, and TSG6 was evaluated after using RT-qPCR in relation to confocal microscopy observations of protein expression and distribution during real-time proliferation of porcine follicular GCs. The COX2 and HAS2 mRNAs were highly expressed after 120 h of in vitro culture (IVC), whereas PTX3 and TSG6 mRNAs were increased during the first 24-48 h of IVC (P less than 0.001, P less than 0.01). Conversely, all of the encoded proteins were highly expressed after 144-168 h of IVC as compared to other culture periods (P less than 0.001, P less than 0.01). When analyzing the realtime proliferation of GCs in vitro, we observed a logarithmic increase of cell proliferation between 0 h and 120 h of IVC. However, after 120-168 h of IVC, the cells reached the lag phase of proliferation. Since it is well accepted that porcine GCs undergo luteinization shortly after 24-48 h of IVC, the expression pattern of investigated genes indicated that Cox2 and Has2 are independent from the LH surge, but their increased levels may be upregulated by cell proliferation in vitro. Moreover, higher expression of PTX3 and TSG6 during first 24 h and/or 48 h of IVC suggested that their levels are accompanied by porcine GCs luteinization process.