New Gene Markers Involved in Molecular Processes of Tissue Repair, Response to Wounding and Regeneration Are Differently Expressed in Fibroblasts from Porcine Oral Mucosa during Long-Term Primary Culture.

The mechanisms of wound healing and vascularization are crucial steps of the complex morphological process of tissue reconstruction. In addition to epithelial cells, fibroblasts play an important role in this process. They are characterized by dynamic proliferation and they form the stroma for epithelial cells. In this study, we have used primary cultures of oral fibroblasts, obtained from porcine buccal mucosa. Cells were maintained long-term in in vitro conditions, in order to investigate the expression profile of the molecular markers involved in wound healing and vascularization. Based on the Affymetrix assays, we have observed three ontological groups of markers as wound healing group, response to wounding group and vascularization group, represented by different genes characterized by their expression profile during long-term primary in vitro culture (IVC) of porcine oral fibroblasts. Following the analysis of gene expression in three previously identified groups of genes, we have identified that transforming growth factor beta 1 (TGFB1), ITGB3, PDPN, and ETS1 are involved in all three processes, suggesting that these genes could be recognized as markers of repair specific for oral fibroblasts within the porcine mucosal tissue.

Cortical Granule Distribution and Expression Pattern of Genes Regulating Cellular Component Size, Morphogenesis, and Potential to Differentiation are Related to Oocyte Developmental Competence and Maturational Capacity In Vivo and In Vitro.

Polyspermia is an adverse phenomenon during mammalian fertilization when more than one sperm fuses with a single oocyte. The egg cell is prepared to prevent polyspermia by, among other ways, producing cortical granules (CGs), which are specialized intracellular structures containing enzymes that aim to harden the zona pellucida and block the fusion of subsequent sperm. This work focused on exploring the expression profile of genes that may be associated with cortical reactions, and evaluated the distribution of CGs in immature oocytes and the peripheral density of CGs in mature oocytes. Oocytes were isolated and then processed for in vitro maturation (IVM). Transcriptomic analysis of genes belonging to five ontological groups has been conducted. Six genes showed increased expression after IVM (ARHGEF2, MAP1B, CXCL12, FN1, DAB2, and SOX9), while the majority of genes decreased expression after IVM. Using CG distribution analysis in immature oocytes, movement towards the cortical zone of the oocyte during meiotic competence acquisition was observed. CGs peripheral density decreased with the rise in meiotic competence during the IVM process. The current results reveal important new insights into the in vitro maturation of oocytes. Our results may serve as a basis for further studies to investigate the cortical reaction of oocytes.

Muscle Cell Morphogenesis, Structure, Development and Differentiation Processes Are Significantly Regulated during Human Ovarian Granulosa Cells In Vitro Cultivation.

Granulosa cells (GCs) have many functions and are fundamental for both folliculogenesis and oogenesis, releasing hormones and communicating directly with the oocyte. Long-term in vitro cultures of GCs show significant stem-like characteristics. In the current study, RNA of human ovarian granulosa cells was collected at 1, 7, 15 and 30 days of long-term in vitro culture. Understanding the process of differentiation of GCs towards different cell lineages, as well as the molecular pathways underlying these mechanisms, is fundamental to revealing other possible stemness markers of this type of cell. Identifying new markers of GC plasticity may help to understand the aetiology and recurrence of a wide variety of diseases and health conditions and reveal possible clinical applications of the ovarian tissue cells, affecting not only the reproductive ability but also sex hormone production. Granulosa cells were the subject of this study, as they are readily available as remnant material leftover after in vitro fertilisation procedures and exhibit significant stem-like characteristics in culture. The change in gene expression was investigated through a range of molecular and bioinformatic analyses. Expression microarrays were used, allowing the identification of groups of genes typical of specific cellular pathways. This candidate gene study focused on ontological groups associated with muscle cell morphogenesis, structure, development and differentiation, namely, "muscle cell development", "muscle cell differentiation", "muscle contraction", "muscle organ development", "muscle organ morphogenesis", "muscle structure development", "muscle system process" and "muscle tissue development". The results showed that the 10 most upregulated genes were keratin 19, oxytocin receptor, connective tissue growth factor, nexilin, myosin light chain kinase, cysteine and glycine-rich protein 3, caveolin 1, actin, activating transcription factor 3 and tropomyosin, while the 10 most downregulated consisted of epiregulin, prostaglandin-endoperoxide synthase 2, transforming growth factor, interleukin, collagen, 5-hydroxytryptmine, interleukin 4, phosphodiesterase, wingless-type MMTV integration site family and SRY-box 9. Moreover, ultrastructural observations showing heterogeneity of granulosa cell population are presented in the study. At least two morphologically different subpopulations were identified: large, light coloured and small, darker cells. The expression of genes belonging to the mentioned ontological groups suggest the potential ability of GCs to differentiate and proliferate toward muscle lineage, showing possible application in muscle regeneration and the treatment of different diseases.

Genes Involved in the Processes of Cell Proliferation, Migration, Adhesion, and Tissue Development as New Potential Markers of Porcine Granulosa Cellular Processes In Vitro: A Microarray Approach.

Proper course of folliculogenesis and oogenesis have an enormous impact on female fertility. Both processes take place in the ovary and involve not only the maturing germ cell, but also few types of somatic cells that assist the ovarian processes and mediate the dialog with the oocyte. These cells, granulosa and theca, are heavily involved in essential reproductive processes, such as ovulation, fertilization, and embryo implantation. In this study, we have used the expressive microarray approach to analyze the transcriptome of porcine granulosa cells, during short-term in vitro culture. We have further selected differentially expressed gene ontologies, involved in cell proliferation, migration, adhesion, and tissue development, namely, "cell-cell adhesion," "cell motility," "cell proliferation," "tissue development," and "tissue migration" to screen them for the possibility of discovery of new markers of those processes. A total of 303 genes, expression of which varied significantly in different culture periods and belonged to the analyzed ontology groups, were detected, of which 15 that varied the most (between 0 and 48 h of culture) were selected for validation. As the validation confirmed the transcriptomic patterns, 10 genes of biggest changes in expression (CAV1, IGFBP5, ITGB3, FN1, ITGA2, LAMB1, POSTN, FAM83D, KIF14, and CDK1) were analyzed, described, and referred to the context of the study, with the most promising new markers and further proof for the viability of the currently recognized ones detailed. Overall, the study provided valuable insight into the molecular functioning of in vitro granulosa cell cultures.

New Gene Markers of Angiogenesis and Blood Vessels Development in Porcine Ovarian Granulosa Cells during Short-Term Primary Culture In Vitro.

The physiological processes that drive the development of ovarian follicle, as well as the process of oogenesis, are quite well known. Granulosa cells are major players in this occurrence, being the somatic element of the female gamete development. They participate directly in the processes of oogenesis, building the cumulus-oocyte complex surrounding the ovum. In addition to that, they have a further impact on the reproductive processes, being a place of steroid sex hormone synthesis and secretion. It is known that the follicle development creates a major need for angiogenesis and blood vessel development in the ovary. In this study, we use novel molecular approaches to analyze markers of these processes in porcine granulosa cultured primarily in vitro. The cells were recovered from mature sus scrofa specimen after slaughter. They were then subjected to enzymatic digestion and culture primarily for a short term. The RNA was extracted from cultures in specific time periods (0h, 24h, 48h, 96h, and 144h) and analyzed using expression microarrays. The genes that exhibited fold change bigger than |2|, and adjusted p-value lower than 0.05, were considered differentially expressed. From these, we have chosen the members of "angiogenesis," "blood vessel development," "blood vessel morphogenesis," "cardiovascular system development," and "vasculature development" for further selection. CCL2, FGFR2, SFRP2, PDPN, DCN, CAV1, CHI3L1, ITGB3, FN1, and LOX which are upregulated, as well as CXCL10, NEBL, IHH, TGFBR3, SCUBE1, IGF1, EDNRA, RHOB, PPARD, and SLITRK5 genes whose expression is downregulated through the time of culture, were chosen as the potential markers, as their expression varied the most during the time of culture. The fold changes were further validated with RT-qPCR. The genes were described, with special attention to their possible function in GCs during culture. The results broaden the general knowledge about GC's in vitro molecular processes and might serve as a point of reference for further in vivo and clinical studies.

"Positive Regulation of RNA Metabolic Process" Ontology Group Highly Regulated in Porcine Oocytes Matured In Vitro: A Microarray Approach.

The cumulus-oocyte complexes (COCs) growth and development during folliculogenesis and oogenesis are accompanied by changes involving synthesis and accumulation of large amount of RNA and proteins. In this study, the transcriptomic profile of genes involved in "oocytes RNA synthesis" in relation to in vitro maturation in pigs was investigated for the first time. The RNA was isolated from oocytes before and after in vitro maturation (IVM). Interactions between differentially expressed genes/proteins belonging to "positive regulation of RNA metabolic process" ontology group were investigated by STRING10 software. Using microarray assays, we found expression of 12258 porcine transcripts. Genes with fold change higher than |2| and with corrected p value lower than 0.05 were considered as differentially expressed. The ontology group "positive regulation of RNA metabolic process" involved differential expression of AR, INHBA, WWTR1, FOS, MEF2C, VEGFA, IKZF2, IHH, RORA, MAP3K1, NFAT5, SMARCA1, EGR1, EGR2, MITF, SMAD4, APP, and NR5A1 transcripts. Since all of the presented genes were downregulated after IVM, we suggested that they might be significantly involved in regulation of RNA synthesis before reaching oocyte MII stage. Higher expression of "RNA metabolic process" related genes before IVM indicated that they might be recognized as important markers and specific "transcriptomic fingerprint" of RNA template accumulation and storage for further porcine embryos growth and development.

Genes of cellular components of morphogenesis in porcine oocytes before and after IVM.

Proper oocyte maturation in mammals produces an oocyte capable of monospermic fertilization and embryo preimplantation. The cumulus-oocyte complexes (COCs), surrounding an oocyte, play a significant role in oocyte maturation. During this process, when the COCs undergo cumulus expansion wherein tightly compact cumulus cells (CCs) form a dispersed structure, permanent biochemical and molecular modifications occur in the maturing oocytes, indicating that the gene expression between immature and mature oocytes differs significantly. This study focuses on the genes responsible for the cellular components of morphogenesis within the developing oocyte. Brilliant cresyl blue (BCB) was used to determine the developmental capability of porcine oocytes. The immature oocytes (GV stage) were compared with matured oocytes (MII stage), using microarray and qRT-PCR analysis to track changes in the genetic expression profile of transcriptome genes. The data showed substantial upregulation of genes influencing oocyte's morphology, cellular migration and adhesion, intracellular communication, as well as plasticity of nervous system. Conversely, downregulation involved genes related to microtubule reorganization, regulation of adhesion, proliferation, migration and cell differentiation processes in oocytes. This suggests that most genes recruited in morphogenesis in porcine oocyte in vitro, may have cellular maturational capability, since they have a higher level of expression before the oocyte's matured form. It shows the process of oocyte maturation and developmental capacity is orchestrated by significant cellular modifications during morphogenesis.

Morphogenesis-related gene-expression profile in porcine oocytes before and after in vitro maturation.

Mammalian oocyte maturation is achieved when oocytes reach metaphase II (MII) stage, and accumulate mRNA and proteins in the cytoplasm following fertilization. It has been shown that oocytes investigated before and after in vitro maturation (IVM) differ significantly in transcriptomic and proteomic profiles. Additionally, folliculogenesis and oogenesis is accompanied by morphogenetic changes, which significantly influence further zygote formation and embryo growth. This study aimed to determine new transcriptomic markers of porcine oocyte morphogenesis that are associated with cell maturation competence. An Affymetrix microarray assay was performed on an RNA template isolated from porcine oocytes before (n = 150) and after (n = 150) IVM. The brilliant cresyl blue (BCB) staining test was used for identification of cells with the highest developmental capacity. DAVID (Database for Annotation, Visualization, and Integrated Discovery) software was used for the extraction of the genes belonging to a cell morphogenesis Gene Ontology group. The control group consisted of freshly isolated oocytes. In total, 12,000 different transcripts were analysed, from which 379 genes were downregulated and 40 were upregulated in oocytes following IVM. We found five genes, SOX9, MAP1B, DAB2, FN1, and CXCL12, that were significantly upregulated in oocytes after IVM (in vitro group) compared with oocytes analysed before IVM (in vivo group). In conclusion, we found new transcriptomic markers of oocyte morphogenesis, which may be also recognized as significant mediators of cellular maturation capacity in pigs. Genes SOX9, MAP1B, DAB2, FN1, and CXCL12 may be involved in the regulation of the MII stage oocyte formation and several other processes that are crucial for porcine reproductive competence.

"Bone Development" Is an Ontology Group Upregulated in Porcine Oocytes Before In Vitro Maturation: A Microarray Approach.

Mammalian cumulus-oocyte complexes (COCs) reach full developmental capability during folliculogenesis and oogenesis. It is well recognized that only gametes achieving MII stage after in vivo or in vitro maturation (IVM) are successfully fertilized by a single spermatozoon. Although the process of oocyte nuclear and/or cytoplasmic maturation in pigs is well determined, there exist many differences that promote these processes in vivo and in vitro. Therefore, this study aimed to investigate the differences in RNA expression profiles between porcine oocytes before and after IVM using microarray and real-time quantitative polymerase chain reaction (RT-qPCR) assays. Experiments were performed on oocytes isolated from 55 pubertal crossbred Landrace gilts. The oocytes were analyzed both before and after IVM and only Brilliant Cresyl Blue (BCB)-positive gametes were used for subsequent microarray analysis (Affymetrix) and RT-qPCR analysis. The microarray assay, which measures expression of 12,258 transcripts, revealed 419 differentially expressed transcripts in porcine oocytes, from which 379 were downregulated and 40 were upregulated before IVM compared to those analyzed after IVM. After DAVID analysis, we found eight different transcripts, including IHH, BMP1, WWTR1, CHRDL1, KLF10, EIF2AK3, MMP14, and STC1. Their expression is related to the "bone development" ontology group and was further subjected to hierarchical clusterization. Using RT-qPCR analysis, we confirmed the results of the microarray assay, showing increased expression of the eight genes in oocytes before IVM compared to oocytes after maturation in vitro. It has been suggested that "bone development" belongs to one ontological group involving genes substantially upregulated in porcine oocytes before IVM. We suggest that the gamete mRNA expression profile before IVM may comprise stored transcripts, which are templates for protein biosynthesis following fertilization. We also hypothesize that these mRNAs may be a specific "fingerprint" of folliculogenesis and oogenesis in pigs.

Expression of genes associated with BMP signaling pathway in porcine oocytes before and after IVM - a microarray approach.

BACKGROUND: The full maturational capability of mammalian oocytes is accompanied by nuclear and cytoplasmic modifications, which are associated with proliferation and differentiation of surrounding cumulus cells. These events are regulated on molecular level by the expression of target genes involved in signal transduction pathways crucial for folliculogenesis and oogenesis. Transforming growth factor beta signaling includes several molecules that are involved in the regulation of oogenesis and embryo growth, including bone morphogenetic protein (BMP). However, the BMP-related gene expression profile in oocytes at different maturational stages requires further investigation. METHODS: Oocytes were isolated from pubertal crossbred Landrace gilts follicles, selected with a use of BCB staining test and analyzed before and after in vitro maturation. Gene expression profiles were examined using an Affymetrix microarray approach and validated by RT-qPCR. Database for Annotation, Visualization, and Integrated Discovery (DAVID) software was used for the extraction of the genes belonging to a BMP-signaling pathway ontology group. RESULTS: The assay revealed 12,258 different transcripts in porcine oocytes, among which 379 genes were down-regulated and 40 were up-regulated. The DAVID database indicated a "BMP signaling pathway" ontology group, which was significantly regulated in both groups of oocytes. We discovered five up-regulated genes in oocytes before versus after in vitro maturation (IVM): chordin-like 1 (CHRDL1), follistatin (FST), transforming growth factor-beta receptor-type III (TGFßR3), decapentaplegic homolog 4 (SMAD4), and inhibitor of DNA binding 1 (ID1). CONCLUSIONS: Increased expression of CHRDL1, FST, TGFßR3, SMAD4, and ID1 transcripts before IVM suggested a subordinate role of the BMP signaling pathway in porcine oocyte maturational competence. Conversely, it is postulated that these genes are involved in early stages of folliculogenesis and oogenesis regulation in pigs, since in oocytes before IVM increased expression was observed.

"Cell Migration" Is the Ontology Group Differentially Expressed in Porcine Oocytes Before and After In Vitro Maturation: A Microarray Approach.

Maturation of cumulus-oocyte complexes (COCs) is crucial for further successful monospermic fertilization, embryo growth, and implantation. All these events are accompanied by proliferation and differentiation of cumulus cells. The migration of COCs to the oviduct after ovulation and the interaction between female gametes and/or embryos with maternal tissues are still poorly recognized on the molecular level. This study was aimed to first demonstrate the mRNA expression profile of cell migration markers during different stages of porcine oocytes maturation and developmental capability in vitro. The COCs were collected from a total of 45 pubertal crossbred Landrace gilts, brilliant cresyl blue (BCB) stained, and analyzed before (n = 150) or after (n = 150) in vitro maturation (IVM). Using the Affymetrix® Porcine Gene 1.1 ST Array, the expression profile of 12,258 porcine transcripts was examined. We found nine genes involved in cell migration mechanisms, that is, PLD1, KIT, LAMA2, MAP3K1, VEGFA, TGFBR3, INSR, TPM1, and RTN4. These genes were upregulated in porcine oocytes before IVM as compared with post-IVM expression analysis. Moreover, important mechanisms of biological interaction between VEGFA-KIT and VEGFA-INSR were also observed. The upregulation and/or downregulation of selected mRNAs expression after microarray assays was checked and approved by real-time quantitative polymerase chain reaction. We suggest that several genes, including LAMA2 or TPM1, encode proteins participating in the formation of the oocyte's protein architecture such as microtubules and kinetochore reorganization. As the expression of all "migration regulatory genes" investigated in this study was significantly upregulated in oocytes before IVM, we conclude that they may contribute to the maturational capability of porcine oocytes. However, migration potency of COCs is not accompanied by achievement of the MII stage by porcine oocytes in vitro. The investigated genes such as PLD1, KIT, LAMA2, MAP3K1, VEGFA, TGFBR3, INSR, TPM1, and RTN4 may be recognized as a new marker of porcine oocytes maturational competence during in vitro culture.

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.

Expression and cellular distribution of zona pellucida glycoproteins in canine oocytes before and after in vitro maturation.

This study was aimed at investigating zona pellucida glycoproteins (ZP) ZP2, ZP3 mRNA expression as well as ZP3, ZP4 (ZPB) protein distribution before and after in vitro maturation (IVM) in canine oocytes. The cumulus-oocyte complexes (COCs) were recovered from 27 anoestrous mongrel bitches and matured for 72 h in TCM199 medium. The canine COCs were analysed before and after IVM. Using real-time quantitative polymerase chain reaction (RQ-PCR), both groups of oocytes were analysed for detection of ZP2 and ZP3 mRNA profiles as well as using confocal microscopic analysis for observation of ZP3 and ZP4 protein distribution. In post-IVM canine oocytes an increase in transcript content of ZP2 and ZP3 genes as well as a decrease in ZP3 and ZP4 protein levels were observed when compared with pre-IVM oocytes. Moreover, the ZP4 protein before IVM was significantly distributed in the peripheral area of cytoplasm, whereas after IVM it was localized rather than in the entire cytoplasm. In contrast, the ZP3 protein was found both before and after IVM was distributed in the peripheral area of the cytoplasm. In conclusion, we suggest that the expression of ZP2 and ZP3 genes is associated with the maturation stage of canine oocytes, as higher mRNAs levels were found after IVM. However, a decreased expression of ZP3 and ZP4 proteins after IVM suggests maturation-dependent down-regulation of these protein translations, which may result in disturbed fertilization.

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

Although the expression of estrogen and progesterone receptors within porcine ovary and cumulus-oocyte complexes (COCs) is well recognized, still little information is known regarding expression of the progesterone receptor (PGR), PGR membrane component 1 (PGRMC1) and of estrogen-related receptors (ERRγ and ERRß/γ) in separated cumulus cells in relation to real-time proliferation. In this study, a model of oocytes-separated cumulus cells was used to analyze the cell proliferation index and the expression PGR, PGRMC1 and of ERRγ and ERRß/γ during 96-h cultivation in vitro using real-time quantitative PCR (qRT-PCR) and confocal microscopic observation. We found that PGR protein expression was increased at 0 h, compared with PGR protein expression after 96 h of culture (P < 0.001). The expression of PGRMC1, ERRγ and ERRß/γ was unchanged. After using qRT-PCR we did not found statistical differences in expression of PGR, PGRMC1, ERRγ and ERRß/γ during 96 h of cumulus cells in vitro culture (IVC). We supposed that the differential expression of the PGR protein at 0 h and after 96 h is related to a time-dependent down-regulation, which may activate a negative feedback. The distribution of PGR, PGRMC1 proteins may be linked with the translocation of receptors to the cytoplasm after the membrane binding of respective agonists and intra-cytoplasmic signal transduction. Furthermore, cumulus cells analyzed at 0 h were characterized by decreased proliferation index, whereas those after 96 h of culture revealed a significant increase of proliferation index, which may be associated with differentiation/luteinization of these cells during real-time proliferation.

Expression of INHßA and INHßB proteins in porcine oocytes cultured in vitro is dependent on the follicle size.

The current study aimed to investigate differential expression of inhibin ßA (INHßA) and inhibin ßB (INHßB) in porcine oocytes before or after in vitro maturation (IVM) isolated from follicles of various sizes. Porcine oocytes isolated from large, medium and small follicles (40 from each) were used to study the INHßA and INHßB protein expression pattern using western blot analysis before or after 44 h of oocyte IVM. An increased expression of INHßA was found in oocytes collected from large and medium follicles compared with small follicles before or after IVM (P < 0.001, P < 0.05, respectively). Similarly, higher INHßB levels were observed in oocytes recovered from large follicles compared with small (P < 0.01). As INHßA and INHßB are expressed in both porcine follicular somatic cells and oocytes, it can be assumed that these transforming growth factor beta (TGFß) superfamily factors are involved in the regulation of molecular bi-directional pathways during follicle and oocyte development, and can be recognized as markers of follicle and oocyte maturation. Moreover, the current study clearly demonstrated that inhibin expression is substantially associated with porcine follicle growth and development.

Real-time proliferation of porcine cumulus cells is related to the protein levels and cellular distribution of Cdk4 and Cx43.

The proper maturation of cumulus somatic cells depends on bidirectional communication between the oocyte and the surrounding cumulus cells (CCs). The aim of this study was (i) to investigate maturation markers, such as Cx43 and Cdk4 protein levels, and (ii) to analyze the distribution of these two proteins in CCs cultured for 44, 88, 132, and 164 hours in both separated and cumulus-enclosed oocyte cultures. CCs were isolated from porcine ovarian follicles after the treatment of the recovered COCs with collagenase. Then, the separated CCs were cultured in TCM-199 for 0 to 164 hours, using a real-time cellular analyzer; however, the immunostaining was performed only after 44, 88, and 132 hours. The protein levels and distribution were analyzed using confocal microscopy. After the CCs underwent in vitro cultivation (IVC) for 25 hours, a logarithmically increasing normalized proliferation index was found throughout the entire 164 hours cultivation time. The Cx43 and Cdk4 proteins were observed at higher levels after 44 hours of culture than before IVC. After 88 and 132 hours of IVC, no significant alterations in either mRNA or protein levels of Cx43 and Cdk4 were found. Cx43 and Cdk4 were localized in the cell nucleus before IVC, whereas after 44, 88, and 132 hours of IVC, both proteins translocated to the cytoplasm. In cumulus-enclosed oocyte cultures, Cdk4 was localized both in the nucleus and cytoplasm, whereas Cx43 was only in the cytoplasm. Additionally, only low levels of the cumulus expansion markers MIS and SNAT3 were observed. In summary, we could demonstrate that the in vitro cultivation of CCs was associated with cell proliferation and that Cx43 and Cdk4 gene expression was upregulated after IVC, resulting in significantly higher protein levels. Moreover, the two proteins translocated from the nucleus to the cytoplasm of the CCs during IVC. The protein distribution is presumably related to different protein functions during bidirectional communication via gap junction communication.

Short-term cultivation of porcine cumulus cells influences the cyclin-dependent kinase 4 (Cdk4) and connexin 43 (Cx43) protein expression--a real-time cell proliferation approach.

The CC (cumulus cell) proliferation index in relation to the expression and distribution of Cdk4 and Cx43 proteins, which are crucial factors for oocyte maturation, was investigated. Cumulus-oocyte complexes (COCs) were recovered from pubertal crossbred Landrace gilts and treated with collagenase, and separated CCs were cultured in standard TCM199 medium for 44 h. At each step of in vitro cultivation (IVC) of CCs (0, 12, 24 and 44 h), a normalized proliferation index was assessed. Cdk4 and Cx43 protein expression and the CC-specific cellular distribution were analyzed by confocal microscopic observation. The normalized proliferation index (number of cells attached, measured by impedance) was increased in the first 12 h of IVC (P<0.01) and differed between 12 h and 24 h of cultivation (P<0.001). Later, between 24 h-44 h of IVC, the CC proliferation rate was stable, and no significant differences were observed. Based on the confocal microscopic observation, increased expression of both Cdk4 and Cx43 was found after 44 h of IVC compared with the expression of these proteins before IVC. Moreover, after IVC, a substantial translocation of Cdk4 and Cx43 was noted from the nucleus to the cytoplasm of CCs. In conclusion, it was demonstrated for the first time that CCs can be cultured in vitro separately without oocytes and that the proliferation index was significantly increased in the first 12 h of IVC, which may reflect the process of ordinary cumulus cell expansion. Furthermore, the expression of both Cdk4 and Cx43 in CCs suggested that these proteins may be regarded as markers not only of proper oocyte maturation but also of CC differentiation. Translocation of these proteins into the cytoplasm of CCs after 44 h of IVC may be related to the expansion process.