Insight into "nuclear-cytoplasmic shuttling" as a developmental and differentiational capability of cells in primary culture models.

Shuttling proteins are molecules that can facilitate transport through the nuclear envelope. A very large number of proteins are involved in this process that includes nuclear pore buildup, signal, receptor and enzyme proteins. There are many examples of proteins whose biological activity depends on nucleocytoplasmic transport. Very often they are largely responsible for the proper occurrence of cell division, maturation, development and differentiation. Thanks to the well mastered methods of in vitro cell culture, it is possible to trace the levels of protein expression and their distribution in cells. Advanced molecular techniques allow for precise determination of their displacement in time. Several studies are still being carried out, using primary cultures, to identify the factors that determine the maturation, development and differentiation of cells. In understanding of the detailed mechanisms controlling cell life, the key is not the level of expression of a specific protein, but its distribution in individual cellular compartments.

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.

Human Wharton's jelly mesenchymal stem cells: properties, isolation and clinical applications.

Human Wharton's jelly mesenchymal stem cells (WJ-MSCs) exhibit CD29, CD79 and CD105 markers, characteristic for mesenchymal cell lines. Under the influence of the appropriate factors, WJ-MSCs can be dedifferentiated to osteoblasts, chondrocytes, adipocytes, myocytes, cardiomyocytes, glial cells and dopaminergic neurons. Wharton's jelly (WJ) is one of the potential sources of mesenchymal stem cells (MSCs) - obtaining these cells does not raise moral or ethical objections, because the umbilical cord (UC) is a regular waste material. The expression of the OCT-4 and Nanog proteins, which are characteristic for WJ-MSCs may indicate that these cells have retained some embryonic character. The collected data suggests that WJMSCs show increased division and telomerase activity compared to bone marrow MSCs (BM-MSCs). The published results showed no human leucocyte antigen (HLA) class II expression, with the possibility of HLA class I modification by WJ-MSCs, allowing for the transplantation of these cells both within the same and other species - which allows the use of human cells in animal models. The results of selected studies indicate that WJ-MSCs can be an essential element of regenerative medicine of the 21st century.

Overview of the different methods used in the primary culture of oral mucosa cells.

The culture of primary cells in vitro has enabled to gain knowledge in the field of cell biology, disease mechanisms and to offer great potential in drug testing. To date, two main techniques of isolating and culturing oral mucosal cells, the direct explant method and the enzymatic method, dominate the literature and practice. In the present study, both techniques are discussed in detail, comparing the advantages and disadvantages of the two approaches in setting up a primary culture of oral mucosal cell. The direct explant technique is well-established and has been commonly used for the past 20-30 years. Although the method of setting up the cultures did not show much variations in the methodology described by authors, the culturing conditions varied according to the aims of the projects.

Expression of PTX3, HAS2 AND TNFAIP6 genes in relation to real-time proliferation of porcine endometrial luminal epithelial cells in primary cultivation model.

Endometrial cells undergo very specific changes associated with reproductive processes. Cells prepare for embryo development by increasing their volume. Then, if fertilization fails, endometrial cells are liable for apoptosis, preparing new cells that are ready for subsequent processes related to the possibility of embryo implantation and the development of pregnancy. PTX3 and TNFAIP6 are absent or reduced in cultured COCs, resulting in a functional change in COC in vitro. In this work, we want to check how PTX3, HAS2 and TNFAIP6 behave in luminal epithelium primary cell culture. Cells obtained during slaughter from porcine specimens were cultured primarily in vitro for 7 days. Their proliferation patterns were then analysed using RTCA, with the expression of genes of interest evaluated with the use of immunofluorescence and RT-qPCR. The results of these changes in the expression of the genes of interest were analysed on each of the seven days of the porcine luminal primary cell culture. Our study showed the increased level of PTX3, HAS2 and TN¬FAIP6 expression at the same hours of primary culture. Rt-qPCR showed a higher level of expression of the PTX3 gene in the first 72 h, at the end of the lag phase (in the phase of stasis in which the cells adapt to the new environment and often die). In contrast, TNFAIP6 expression increases about 96 hours when the cells are in the full log phase (logarithmic phase growth) and continue this trend in the plateau phase. We did not observe such drastic changes in the HAS2 expression pattern, which leads us to hypothesize that PTX3 and TNFAIP6 are designed to maintain a constant level of HAS2 in the cell throughout its lifetime. The obtained results could become a point of reference for further in vivo and clinical research.

Gene expression regulating lipopolysaccharide and lipid metabolic processes in porcine oral mucosal cells in long-term primary in vitro culture.

Lipids are an alternative energy source for cells and provide structural integrity in cell membrane and their metabolism is regulated with the use of different pathways, such as integrin signalling, oxidative stress, mechanical stress, and pH changes. All of those processes take place in the oral mucosa which is subject to different environmental impacts. In this study, porcine buccal pouch mucosal cells (pBPMCs) were used during long-term primary in vitro culture. The cultured cells were collected at 7, 15 and 30 days of IVC and subsequently transferred to RNA isolation. In the results of the following microarray analysis, we analyzed the genes detected, belonging to ontology groups, such as "cellular lipid metabolic process", "response to lipid" and "response to lipopolysaccharides. All of the genes involved in these ontological groups were expressed at higher levels at 7 days of IVC and substantially decreased in expression at days 15 and 30 of primary culture. We observed new genes, which may be recognized as markers in regulation of lipid metabolism in mucosal cells in vitro. The results suggested that the biochemical mechanism-involved lipids were accompanied by increased enzymatic activation and synthesis of crucial growth factors reaching high activity at day 7 of culture, which is also well documented as a stage of tissue regeneration period within oral mucosa. Therefore, this "biochemical fingerprint" may be an additional checkpoint of the integrity, resistance and easy adaptability of oral tissues, which are important conditions of success in tissue engineering and grafting for tissue reconstruction.

The p75 neurotrophin receptor in cells of oral mucosal epithelium.

The p75 neurotrophin receptor (p75NTR) can play different roles in cells. This protein can on the one hand act in the regulation of cell growth and survival, while being an apoptosis inducing factor in different contexts. p75NTR regulates cell cycle not only in nerve cells but also in epithelial oral mucosal cells. In the former, neurotrophin-p75NTR signaling affects cell growth and survival. Recent studies showed that p75NTR is expressed in basal cells of oral mucosal epithelium and can be used as one of the markers of epithelial stem/progenitor cells. This role of p75NTR can be utilised in aspects such as tissue engineering and gene therapy. One of the examples of clinical use of cultivated oral mucosal cells is ocular surface reconstruction. p75NTR can be a significant marker of stem cells in studies of epithelial tissues, especially when the cells will exhibit other specific markers, such as CK13, CK14 and PCNA..

Role of macrophages in the pathogenesis of atherosclerosis and aortocoronary graft disease.

Atherosclerosis and disease of graft implanted to bypass occluded coronary or peripheral arteries are similar processes. Patency of implanted grafts is of paramount importance in respect to long-term outcomes. Although few cell types participate in atherosclerotic plaque formation, macrophages play a crucial role. In this article we review the fate of monocytes that infiltrate vessel wall following endothelium damage, and then undergo transformation to macrophages (identified as CD68 positive cells) and eventually lead to severe stenosis of vessel. Opposing biological activity of two subpopulations of macrophages and their impact on plaque instability and its calcification is also presented. At the end of this paper, a possible clinical significance of pre-existing, CD68 positive cell infiltration of vessel wall, applied as aortocoronary grafts, is discussed.

Haematopoiesis: “living in the shadow” of stem cell differentiation.

Haematopoiesis is one of the most well understood stem-cell associated processes. It is a process in which pluripotent hematopoietic stem cells (HSCs) self-proliferate and differentiate into all types of blood cells. The process takes place in marrow of the flat bones in adults, however its location changes several times through embryonic and foetal development. Given the broad range of blood cells and the major differences in their build and function, together with the fact that their numbers need to be maintained within relatively narrow margins in order to maintain homeostasis despite changing environmental conditions, makes the whole process of haematopoiesis highly regulated and depending on a variety of growth factors. When influenced by those, HSCs undergo several irreversible steps, with every next one committing them to an even more specialised fate, ending with all the specific types of mostly short-lived blood cells, that are unable to proliferate on their own and need constant replenishment from the HSC pool. Because the process of haematopoiesis is the only source of all the members of the group of cells performing a range of highly important roles in functioning of the organism, significant damage to the underlying stem cells can cause a range of severe diseases. Many treatments are suggested for managing their symptoms or slowing progress, with bone marrow transplant being one of the only ones that offer possible permanent solution and, despite being a relatively risky procedure, is being widely performed, with the methods constantly improving in order to achieve progressively better results in both treatability and survivability of the patients.

Gender and age-related variability of macrophage representation in the internal thoracic artery wall: does it matter?

Some recent reports suggested that elderly and female patients did not benefit from implantation of the second internal thoracic artery (ITA) during coronary artery bypass surgery (CABG). Macrophages, among other cells, were described to be involved in both atherosclerosis and aortocoronary grafts failure. The aim of the study was to examine the age and gender association with different distribution of CD68+ cells within the layers of ITA wall. This study involved 158 consecutive patients (95 male and 63 female), with the mean age of 64.5±9.5 years, who underwent elective CABG procedures. During surgery, the surplus distal segments of ITA were harvested for immunohistochemical analysis. The number and distribution of CD68+ cells was calculated and plotted against the age and gender of the study participants. CD68+ cells were present in all of the harvested ITA fragments (median 44), more in women (55) than in men (42) (p less than 0.001). However, this difference was of statistical significance exclusively in the tunica intima. Approximately 70% of macrophages were found in the tunica adventitia. The total number of CD68+ cells the in arterial wall as well as in the tunica intima and adventitia correlated positively with the age of patients (r=0.544, r=501 and r=0.462, respectively). The lack of significant advantages of the use of two thoracic arteries, in elderly patients and women, might have resulted from the larger population of CD68+ cells in their walls, especially the tunica intima. However, this result from immunohistochemical analysis needs validation in long-term clinical research on a larger cohort of patients.

Balance between epithelial and stromal marker expression and distribution in primary culture model of porcine endometrium during real-time cell proliferation..

The similarity between humans and pigs, when it comes to tissue morphology, makes Sus scrofa not only a good research model, but also a potential source of cells for tissue engineering. Cell samples obtained from the pig donor, could be influenced in vitro, in order to become a source of tissue material for xenotransplantation, reconstructive and regenerative medicine. Significant amounts of data point to especially major similarities in pig and human reproductive systems. Because of that, particular scientific focus is centered on research concerning porcine COCs, theca and granulosa cells in primary cultures. One of the aspects of the reproductive process, that is still largely undiscovered, is the interaction between preimplantation blastocyst and maternal uterine tissues. In this study, we used molecular analysis techniques, such as RT-qPCR and immunocytochemistry, to analyze the expression and distribution of cytokeratin 18 and panCytokeratins 8, 18 and 19 and vimentin in porcine luminal endometrial epithelial cells, coupled with analysis of their behavior in RTCA. The results have confirmed the presence of epithelial, as well as stromal cell markers in the cells, varying in levels at different stages of culture. They have also given insight into the modes of proliferation and differentiation of studied cells in in vitro culture, as well as providing additional proof for the possible mesenchymal transdifferentiation of epithelial cells.

Genes involved in regulation of cellular metabolic processes, signaling and adhesion are the markers of porcine buccal pouch mucosal cells long-term primary cultured in vitro.

Extraordinary abilities for continuous proliferation and differentiation, associated with constant renewal triggered by stimulation from the mastication process, together with the relative lack of aesthetic complications associated with post-surgery healing, have highlighted buccal pouch mucosa as a potential source of explants that could be used in transplantation and tissue engineering. Additionally, this tissue plays a major role in the oral drug delivery process, which brings special interest to its molecular properties in the context of new drug development. There is therefore a need to analyse the exact mechanisms of oral mucosa functioning, especially when it comes to the processes that are associated with the potential clinical applications. In this study we analysed a complete transcriptome of long-term in vitro cultures of porcine buccal pouch oral mucosa cells. Using a microarray approach, we focused on genes associated with cellular metabolic processes, signalling and adhesion, from 4 gene ontology groups: "Positive regulation of cellular component movement", "Positive regulation of cellular process", "Positive regulation of intracellular signal transduction" and "Single organism cell adhesion". Nineteen genes (CCL8, CXCL2, PLK2, DUSP5, PTGS2, LIF, CCL2, ATP1B1, REL, ITGB3, SCARB1, UGCG, PDPN, LYN, ETS1, FCER1G, TGFB1, RFC4, LMO2) with fold changes higher than |2| and p value Extraordinary abilities for continuous proliferation and differentiation, associated with constant renewal triggered by stimulation from the mastication process, together with the relative lack of aesthetic complications associated with post-surgery healing, have highlighted buccal pouch mucosa as a potential source of explants that could be used in transplantation and tissue engineering. Additionally, this tissue plays a major role in the oral drug delivery process, which brings special interest to its molecular properties in the context of new drug development. There is therefore a need to analyse the exact mechanisms of oral mucosa functioning, especially when it comes to the processes that are associated with the potential clinical applications. In this study we analysed a complete transcriptome of long-term in vitro cultures of porcine buccal pouch oral mucosa cells. Using a microarray approach, we focused on genes associated with cellular metabolic processes, signalling and adhesion, from 4 gene ontology groups: "Positive regulation of cellular component movement", "Positive regulation of cellular process", "Positive regulation of intracellular signal transduction" and "Single organism cell adhesion". Nineteen genes (CCL8, CXCL2, PLK2, DUSP5, PTGS2, LIF, CCL2, ATP1B1, REL, ITGB3, SCARB1, UGCG, PDPN, LYN, ETS1, FCER1G, TGFB1, RFC4, LMO2) with fold changes higher than |2| and p value less than 0.05 were identified, described in context and analysed. While the study needs much further validation to become applicable in a clinical environment, it yields valuable information about the transcriptomic basis of oral mucosal cell functioning in vitro, that might serve as a reference for further research, aiming to apply this knowledge in clinical situations.0.05 were identified, described in context and analysed. While the study needs much further validation to become applicable in a clinical environment, it yields valuable information about the transcriptomic basis of oral mucosal cell functioning in vitro, that might serve as a reference for further research, aiming to apply this knowledge in clinical situations.

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 connexins in porcine buccal pouch mucosa cells during real-time long-term cell proliferation in vitro: a primary culture approach.

In this study we investigated the expression of connexins Cx36, Cx37, Cx40, Cx43, and Cx45 mRNAs during real-time cellular proliferation in vitro. The oral mucosa cells were isolated from 80 pubertal crossbred Landrace gilts. The cells were transferred into primary in vitro culture (IVC) and cultured for 30 days. The cells were collected to RNA isolation after 7, 15 and 30 days of IVC and were checked for their real-time proliferative status using real-time cell analysis (RTCA). We found an increased expression of Cx43 mRNA after 30 days of IVC as compared to control (P<0.05). The expression level of Cx36 was significantly decreased after 30 days. The expression of Cx37, Cx40 and Cx45 mRNAs was not changed. The expression of Cx43 was statistically increased when compared to Cx40, Cx37, Cx45 and Cx36 (P<0.001, for all time periods, respectively). We confirmed the expression of selected connexins in porcine buccal mucosa cells during their long-term primary IVC, which suggests the existence of functional gap junction connections (GJCs) communication network between these cells. We also confirmed the observations of other authors that Cx43 plays a substantial role in GJC structure. However, the increased expression of Cx43 in buccal mucosa cells, accompanied with their proliferation during real-time primary culture, is presented, to our knowledge, for the first time.

Expression of genes responsible for cell morphogenesis involved in differentiation in porcine buccal pouch mucosal cells during long-term primary culture and real-time proliferation in vitro.

Recently, using experimental animal model, we demonstrated that porcine buccal pouch mucosal cells reflect increased proliferation capability during primary cultivation in vitro. Although the histological structure and morphogenesis in oral cavity is well recognized, the molecular mechanisms which regulate this process still need further investigation. This study was aimed to analyze the molecular marker expression profile involved in morphogenesis and differentiation capacity of porcine buccal pouch mucosal cells during their long-term primary cultivation in vitro. The experiment was performed on buccal pouch mucosal cells isolated from 80 pubertal crossbred Landrace gilts. After collection, the cells were treated enzymatically and transferred into a primary in vitro culture (IVC) system and cultured for 30 days. The cells were collected for RNA isolation after 7, 15 and 30 days of IVC and were checked for their real-time proliferative status using the RTCA system. We found an increased expression of FN1 and SOX9 genes when calculated against ACTB after 7, and 30 days of IVC, (P less than 0.01, P less than 0.001, respectively). The CXCL12 mRNA was down-regulated after 7, 15 and 30 days of IVC, but not statistically significant. Similar expression profile was observed when calculated against HPRT, however, DAB2 was found to be higher expressed at day 15 of IVC, (P less than 0.05). The cell index measured during real-time cell proliferation was substantially increased between 96 h and 147h of IVC and reached the log phase. Since FN1 and SOX9 revealed significant increase of expression after long-term culture in vitro, it is suggested that expression of these differentiation and stemness genes is accompanied by cell proliferation. Moreover, FN1 and SOX9 might be recognized as new markers of buccal pouch mucosal cell proliferation and differentiation in pigs in in vitro primary culture model.

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.