Distribution of the intermediate filament proteins vimentin, keratin, and desmin in the bovine ovary

Characterization of an incipient granulosa cell tumour in a Holstein cow: Steroid hormone receptors and coregulators expression

The objective of this study was to describe a case of a granulosa cell tumour (GCT) of incipient formation and to characterize it by its immunohistochemical pattern and hormonal profile. The case presented corresponds to a 7-year-old Holstein cow without reproductive disorders. No alterations were observed at rectal palpation, neither in the ultrasonography nor in the hormonal profile. A GCT concomitant with normal follicular development was diagnosed. Through a panel of immunohistochemical markers, a highly differentiated pattern could be determined in the GCT, which preserves the expression of steroid receptors (ESR1, ESR2 and PR) typical of granulosa cells, but does not express the enzymes for the synthesis of androgens (CYP17A1) and oestrogens (CYP19A1). In addition, the expression of co-regulators of steroid hormone receptors and neuroendocrine markers was described for the first time in a GCT in cattle. These results increase the information about GCTs in cattle before the ovarian function is compromised.

Silencing of keratin 17 by lentivirus-mediated short hairpin RNA inhibits the proliferation of PANC-1 human pancreatic cancer cells

Keratin 17 (KRT17) has been demonstrated to be a potential biological marker for the prediction of prognosis in particular types of cancer. The aim of the present study was to investigate the molecular mechanisms underlying the function of KRT17 in the pancreatic cancer (PAC) cell line PANC-1 and the potential of KRT17 as a therapeutic target for PAC. KRT17 expression levels were analyzed using quantitative PCR and compared with histological data using bioinformatics tools in PAC samples and three human PAC cell lines. Cell proliferation was determined using an MTT assay, in addition to cell cycle distribution and apoptosis analysis using flow cytometry, colony formation assay using Giemsa staining and cell motility analysis using a Transwell migration assay. Tumor growth was evaluated in vivo in nude mice. The expression levels of a number of signaling molecules were measured to establish the potential mechanism by which silencing KRT17 expression affected PAC PANC-1 cells. Increased levels of KRT17 expression were observed in human PAC compared with normal tissues, as well as in three human PAC cell lines (MIA PaCa-2, PANC-1 and KP-3 cells) compared with the H6c7 human immortal pancreatic duct epithelial cell line. High expression levels of KRT17 in PAC samples were associated with poor overall survival (P=0.036) and disease-free survival (P=0.017). Lentivirus-mediated KRT17 silencing inhibited cell proliferation, colony formation and migration, but promoted apoptosis and resulted in cell cycle arrest in the G₀/G₁ phase in PANC-1 cells. In addition, KRT17 knockdown inhibited in vivo tumor growth. KRT17 knockdown induced dysregulation of ERK1/2 and upregulation of the pro-apoptotic Bcl-2 protein Bad. In conclusion, the present study demonstrated that elevated KRT17 levels are positively associated with pancreatic cancer progression; KRT17 knockdown suppressed cell growth, colony formation, migration and tumor growth, and induced apoptosis and cell cycle arrest, affecting ERK1/2/Bad signaling. Therefore, the results of the present study suggested that KRT17 may be a potential target for the treatment of pancreatic cancer.

Histology of the Ovary of the Laying Hen (Gallus domesticus)

The laying hen (Gallus domesticus) is a robust animal model for epithelial ovarian cancer. The use of animal models is critical in identifying early disease markers and developing and testing chemotherapies. We describe the microscopic characteristics of the normally functioning laying hen ovary and proximal oviduct to establish baselines from which lesions associated with ovarian cancer can be more readily identified. Ovaries and oviducts were collected from 18-month-old laying hens (n = 18) and fixed in 10% neutral buffered formalin. Hematoxylin- and eosin-stained sections were examined by light microscopy. Both post-ovulatory follicular regression and atresia of small follicles produce remnant clusters of vacuolated cells with no histological evidence that scar tissue persists. Infiltrates of heterophils are associated with atresia of small follicles, a relationship not previously documented in laying hen ovaries. Because these tissues can be mistaken for cancerous lesions, we present a detailed histological description of remnant Wolffian tissues in the laying hen ovary. Immunohistochemical staining for pancytokeratin produced a positive response in ovarian surface epithelium and staining for vimentin produced a positive response in granulosa cells of follicles. Epithelial cells lining glands of the remnant epoöphoron had a positive response to both pancytokeratin and vimentin, a result also observed in women.

Expression of Epithelial and Mesenchymal Differentiation Markers in the Early Human Gonadal Development

Expressions of cytokeratin 8 (CK8), vimentin, nestin, and alpha-smooth-muscle-actin (alpha-SMA) were analyzed in the developing gonads of 12, 5-9 week old (W) human conceptuses by immunohistochemistry and immunofluorescence. During the investigated period, the number of CK8 positive cells increased from 56% to 92% in the gonadal surface epithelium, from 50% to 60% in the stroma, and from 23% to 42% in the medulla. In the early fetal period, the cell expression of CK8 increased in all gonadal parts, whereas primordial germ cells (PGC) remained negative. The expression of vimentin increased in the gonad stroma (gs) from 73% to 88%, and in the surface epithelium from 18% to 97% until ninth W. The medulla had the highest expression of vimentin in the seventh to eighth W (93%). Vimentin and CK8 colocalized in the somatic cells, while some PGCs showed vimentin expression only. Initially, nestin was positive in the gonad surface epithelium (8%) and stroma (52%), however during further development it decreased to 1% and 33%, respectively. In the early fetal period, the nestin positive cells decreased from 44% to 31% in the gonad medulla. Alpha-SMA was positive only in the blood vessels and mesonephros. The described pattern of expression of intermediate filaments (IF) in developing human gonads suggests their role in the control of PGC apoptosis, early differentiation of gs cells and cell migration. Both epithelial and mesenchymal origins of follicular cells and possible epithelial-to-mesenchymal transition of somatic cells is proposed. Lastly, IF intensity expression varies depending on the cell type and developmental period analyzed. Anat Rec, 300:1315-1326, 2017. © 2017 Wiley Periodicals, Inc.

Does myo-inositol effect on PCOS follicles involve cytoskeleton regulation?

Inositol metabolism is severely impaired in follicles obtained from cystic ovaries, leading to deregulated insulin transduction and steroid synthesis. On the contrary, inositol administration to women suffering from polycystic ovary syndrome (PCOS) has been proven to efficiently counteract most of the clinical hallmarks displayed by PCOS patients, including insulin resistance, hyperandrogenism and oligo-amenorrhea. We have recently observed that myo-inositol induces significant changes in cytoskeletal architecture of breast cancer cells, by modulating different biochemical pathways, eventually modulating the epithelial-mesenchymal transition. We hypothesize that inositol and its monophosphate derivatives, besides their effects on insulin transduction, may efficiently revert histological and functional features of cystic ovary by inducing cytoskeleton rearrangements. We propose an experimental model that could address not only whether inositol modulates cytoskeleton dynamics in both normal and cystic ovary cells, but also whether this effect may interfere with ovarian steroidogenesis. A more compelling understanding of the mechanisms of action of inositol (and its derivatives) would greatly improve its therapeutic utilization, by conferring to current treatments a well-grounded scientific rationale.

Molecular manipulation of keratin 8/18 intermediate filaments: modulators of FAS-mediated death signaling in human ovarian granulosa tumor cells

Background

Granulosa cell tumors (GCT) are a rare ovarian neoplasm but prognosis is poor following recurrence. Keratin intermediate filaments expressed in these tumors are a diagnostic marker, yet paradoxically, may also constitute a target for therapeutic intervention. In the current study, we evaluated keratin 8/18 (K8/18) filament expression as a mechanism of resistance to apoptosis in GCT, specifically focusing on regulation of the cell surface death receptor, Fas (FAS).

Methods

The GCT cell line, KGN, was transiently transfected with siRNA to KRT8 and KRT18 to reduce K8/18 filament expression. Expression of K8/18, FAS, and apoptotic proteins (PARP, cleaved PARP) were evaluated by fluorescence microscopy, flow cytometric analysis, and immunoblotting, respectively. The incidence of FAS-mediated apoptosis in KGN cells was measured by caspase 3/7 activity. All experiments were performed independently three to six times, using a fresh aliquot of KGN cells for each experiment. Quantitative data were analyzed by one- or two-way analysis of variance (ANOVA), followed by a Tukey’s post-test for multiple comparisons; differences among means were considered statistically significant at P < 0.05.

Results

Control cultures of KGN cells exhibited abundant K8/18 filament expression (~90 % of cells), and minimal expression of FAS (<25 % of cells). These cells were resistant to FAS-activating antibody (FasAb)-induced apoptosis, as determined by detection of cleaved PARP and measurement of caspase 3/7 activity. Conversely, siRNA-mediated knock-down of K8/18 filament expression enhanced FAS expression (> 70 % of cells) and facilitated FasAb-induced apoptosis, evident by increased caspase 3/7 activity (P < 0.05). Additional experiments revealed that inhibition of protein synthesis, but not MEK1/2 or PI3K signaling, also prompted FasAb-induced apoptosis.

Conclusions

The results demonstrated that K8/18 filaments provide resistance to apoptosis in GCT by impairing FAS expression. The abundance of keratin filaments in these cells and their role in apoptotic resistance provides a greater mechanistic understanding of ovarian tumorgenicity, specifically GCT, as well as a clinically-relevant target for potential therapeutic intervention.

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

The expression of cytoskeletal proteins was evaluated immunohistochemically in 36 normal ovaries sampled from 18 sows and 44 cystic ovaries sampled from of 22 sows, was evaluated. All sows had history of reproductive problems, such as infertility or subfertility. The immunohistochemically stained area (IHCSA) was quantified through image analysis to evaluate the expression of these proteins in the follicular wall of secondary, tertiary, and cystic follicles. Cytokeratins (CK) immunoreactivity was strong in the granulosa cell layer (GC) and mild in the theca interna (TI) and externa (TE) of the normal follicles. There was severe reduction of the reaction to CK in the GC in the cystic follicles, mainly in the luteinized cysts. The immunoreactivity for vimentin was higher in the GC from normal and cystic follicles in contrast with the other follicular structures. In the luteinized cysts, the IHCSA for vimentin was significantly higher in TI and in both observed cysts, the labeling was more accentuated in TE. Immunohistochemical detection of desmin and α-SMA was restricted to the TE, without differences between the normal and cystic follicles. The results of the current study show that the development of ovarian cysts in sows is associated to changes in the expression of the cytoskeletal proteins CK and vimentin.

Stem cells, progenitor cells, and lineage decisions in the ovary

Exploring stem cells in the mammalian ovary has unleashed a Pandora's box of new insights and questions. Recent evidence supports the existence of stem cells of a number of the different cell types within the ovary. The evidence for a stem cell model producing mural granulosa cells and cumulus cells is strong, despite a limited number of reports. The recent identification of a precursor granulosa cell, the gonadal ridge epithelial-like cell, is exciting and novel. The identification of female germline (oogonial) stem cells is still very new and is currently limited to just a few species. Their origins and physiological roles, if any, are unknown, and their potential to produce oocytes and contribute to follicle formation in vivo lacks robust evidence. The precursor of thecal cells remains elusive, and more compelling data are needed. Similarly, claims of very small embryonic-like cells are also preliminary. Surface epithelial cells originating from gonadal ridge epithelial-like cells and from the mesonephric epithelium at the hilum of the ovary have also been proposed. Another important issue is the role of the stroma in guiding the formation of the ovary, ovigerous cords, follicles, and surface epithelium. Immune cells may also play key roles in developmental patterning, given their critical roles in corpora lutea formation and regression. Thus, while the cellular biology of the ovary is extremely important for its major endocrine and fertility roles, there is much still to be discovered. This review draws together the current evidence and perspectives on this topic.

Maternal acrylamide treatment reduces ovarian follicle number in newborn guinea pig offspring

Acrylamide is an industrial chemical which has toxic effects on reproduction. In this study, we investigated whether acrylamide administered prenatally can induce follicular atresia in the newborn guinea pig ovary. Another aim was to describe the localization of vimentin filaments and determine their participation in atresia. After prenatal acrylamide treatment, the pool of primordial and primary follicles was significantly reduced. The number of caspase 3 and TUNEL positive oocytes increased compared to the control group. There were no differences in Lamp1 (autophagy marker) staining. A vimentin immunosignal was present in the granulosa cells of primordial, primary and secondary follicles. Interestingly, in contrast to the control group, the oocytes from all follicles in the ACR-treated females were negative for vimentin. These data suggest that prenatal exposure to acrylamide reduced the number of ovarian follicles by inducing follicular atresia mediated by oocyte apoptosis. Acrylamide-induced apoptosis may be associated with destruction of vimentin filaments.

Effect of porcine follicular fluid proteins and peptides on oocyte maturation and their subsequent effect on in vitro fertilization

The follicular fluid (FF) is a microenvironment that contains molecules involved in oocyte maturation, ovulation, and fertilization. Characterizing the proteins and peptides present in the FF could be useful for determining which proteins and peptides to use as a supplement for culture media. Biologically active peptides produced during the maturation or degradation of functional proteins are called cryptides. The aim of this study was to identify the proteins and cryptides in porcine FF that could stimulate porcine oocyte in vitro maturation (IVM) and in vitro fertilization (IVF) when added to culture maturation medium. Five FF protein fractions (F1-F5) were obtained by ionic exchange chromatography, resolved by SDS-PAGE, and identified by tandem mass spectrometry. These fractions had effects on IVM and/or IVF. The F1 fraction, which was composed of immunoglobulin fragments, cytokeratin, transferrin, and plasminogen precursor increased IVM and IVF. The F2, F3, and F4 fractions reduced the percentage of oocytes in first metaphase. Additionally, the F3 fraction, which was composed of immunoglobulins and transthyretin, interfered with germinal vesicle breakdown. The F5 fraction, which was mainly composed of serum albumin and keratin, favored germinal vesicle breakdown and promoted IVM. Most of the 31 proteins which were associated with the immune response and inflammatory processes could be related to oocyte maturation and fertilization. Some of the identified proteins were present in more than one fraction; this could be explained by a change in their isoelectric points, because of the loss of part of the amino acid sequence or a change in the glycosylation status of the protein. Improved oocyte IVM and IVF will increase embryo production, which in turn will contribute to the efficiency of assisted reproduction in various mammalian species.

A new model of development of the mammalian ovary and follicles

Ovarian follicular granulosa cells surround and nurture oocytes, and produce sex steroid hormones. It is believed that during development the ovarian surface epithelial cells penetrate into the ovary and develop into granulosa cells when associating with oogonia to form follicles. Using bovine fetal ovaries (n = 80) we identified a novel cell type, termed GREL for Gonadal Ridge Epithelial-Like. Using 26 markers for GREL and other cells and extracellular matrix we conducted immunohistochemistry and electron microscopy and chronologically tracked all somatic cell types during development. Before 70 days of gestation the gonadal ridge/ovarian primordium is formed by proliferation of GREL cells at the surface epithelium of the mesonephros. Primordial germ cells (PGCs) migrate into the ovarian primordium. After 70 days, stroma from the underlying mesonephros begins to penetrate the primordium, partitioning the developing ovary into irregularly-shaped ovigerous cords composed of GREL cells and PGCs/oogonia. Importantly we identified that the cords are always separated from the stroma by a basal lamina. Around 130 days of gestation the stroma expands laterally below the outermost layers of GREL cells forming a sub-epithelial basal lamina and establishing an epithelial-stromal interface. It is at this stage that a mature surface epithelium develops from the GREL cells on the surface of the ovary primordium. Expansion of the stroma continues to partition the ovigerous cords into smaller groups of cells eventually forming follicles containing an oogonium/oocyte surrounded by GREL cells, which become granulosa cells, all enclosed by a basal lamina. Thus in contrast to the prevailing theory, the ovarian surface epithelial cells do not penetrate into the ovary to form the granulosa cells of follicles, instead ovarian surface epithelial cells and granulosa cells have a common precursor, the GREL cell.

Expression of intermediate filaments in the Balbiani body and ovarian follicular wall of the Japanese quail (Coturnix japonica)

In the present study, we examined the distribution of 6 groups of intermediate filaments (IFs; cytokeratins, CKs, vimentin, synemin, desmin, glial fibrillary acidic protein and lamins) in oocytes and follicular walls of the Japanese quail (Coturnix japonica) during their development using immunohistochemical and ultrastructural techniques. A distinctly vimentin- and synemin-positive Balbiani body, which is a transient accumulation of organelles (mitochondria, Golgi complex and endoplasmic reticulum) that occurs in the oocytes of all vertebrates including birds, could be detected in the oocytes of primordial and early pre-vitellogenic follicles. In larger pre-vitellogenic follicles, the Balbiani body has dispersed and the positivity of the granulosa cells appeared to concentrate in the basal portion of their cytoplasm. Our ultrastructural data demonstrated that the matrix of the Bal-biani body consists of fine IFs, which may play a role in the formation and dispersion of the Balbiani body. Of the CKs studied (panCK, CK5, CK7, CK8, CK14, CK15, CK18 and CK19), only CK5 showed a slight positive staining in both the theca externa and the Balbiani bodies of pre-vitellogenic oocytes. In conclusion, our data, which describe the changes in avian IF protein expression during folliculogenesis, suggest that the functions of the IFs (vimentin and synemin) of oocytes and follicular walls are not primarily mechanical but may be involved in the transient tethering of mitochondria in the area of the Balbiani body and in the gain of endocrine competence during the differentiation of granulosa cells.

Estrous cycle-dependent changes of Fas expression in the bovine corpus luteum: influence of keratin 8/18 intermediate filaments and cytokines

BACKGROUND

Fas expression and Fas-induced apoptosis are mechanisms attributed to the selective destruction of cells of the corpus luteum (CL) during luteal regression. In certain cell-types, sensitivity to these death-inducing mechanisms is due to the loss or cleavage of keratin-containing intermediate filaments. Specifically, keratin 8/18 (K8/K18) filaments are hypothesized to influence cell death in part by regulating Fas expression at the cell surface.

METHODS

Here, Fas expression on bovine luteal cells was quantified by flow cytometry during the early (Day 5, postovulation) and late stages (Days 16-18, postovulation) of CL function, and the relationship between Fas expression, K8/K18 filament expression and cytokine-induced cell death in vitro was evaluated.

RESULTS

Both total and cell surface expression of Fas on luteal cells was greater for early versus late stage bovine CL (89% vs. 44% of cells for total Fas; 65% vs.18% of cells for cell surface Fas; respectively, P<0.05, n=6-9 CL/stage). A similar increase in the steady-state concentration of mRNA for Fas, as detected by quantitative real-time polymerase chain reaction, however, was not observed. Transient disruption of K8/K18 filaments in the luteal cells with acrylamide (5 mM), however, had no effect on the surface expression of Fas (P>0.05, n=4 CL/stage), despite evidence these conditions increased Fas expression on HepG2 cells (P<0.05, n= 3 expts). Exposure of the luteal cells to cytokines induced cell death (P<0.05) as expected, but there was no effect of K8/K18 filament disruption by acrylamide (P>0.05) or stage of CL (P>0.05, n= 4 CL/stage) on this outcome.

CONCLUSION

In conclusion, we rejected our null hypothesis that the cell surface expression of Fas does not differ between luteal cells of early and late stage CL. The results also did not support the idea that K8/K18 filaments influence the expression of Fas on the surface of bovine luteal cells. Potential downstream effects of these filaments on death signaling, however, remain a possibility. Importantly, the elevated expression of Fas observed on cells of early stage bovine CL compared to late stage bovine CL raises a provocative question concerning the physiological role(s) of Fas in the corpus luteum, particularly during early luteal development.

Immunocytochemical localization of cytoplasmic and nuclear intermediate filaments in the bovine ovary during folliculogenesis

The cellular cytoskeleton is composed of three fibrillar systems, namely actin microfilaments, microtubules and intermediate filaments (IFs). It not only is a structural system, which mediates functional compartmentalization, but also contributes to many cellular processes such as transport, mitosis, secretion, formation of cell extensions, intercellular communication and apoptosis. In this study, we have examined the distribution of four groups of IFs [cytokeratins (CKs), vimentin, desmin and lamins] in the somatic and germinal cells of the bovine ovary using RT-PCR and immunohistochemical techniques. Using RT-PCR, specific transcripts for all intermediate proteins studied (CK8, CK18, desmin, vimentin, lamin A/C and lamin B1) were detected. A characteristic immunohistochemical staining pattern was observed for the different IFs within the ovary. In this study, we used antibodies against type I CK (acidic CKs: CK14, CK18 and CK19) and type II CK (basic CKs: CK5 and CK8). Among these, only antibodies against CK18 gave a characteristic pattern of immunostaining in the ovary, which included the surface epithelium, the follicle cells, the endothelium of blood vessels and rete ovarii. Antibodies against all other CKs resulted in a weak staining of a limited number of cellular structures (CK5 and CK19) or were completely negative (CK8 and CK14, apart from the surface epithelium). Vimentin antibodies resulted occasionally in a weak staining of the granulosa cells of primary and secondary follicles. In late secondary follicles, the basal and the most apical follicle cells contacting the zona pellucida usually showed a marked immunostaining for vimentin. In antral follicles, three different immunostaining patterns for vimentin were observed. Desmin immunostaining was confined to the smooth muscle cells of blood vessels. Although mRNA for lamin A/C and lamin B1 could be demonstrated using RT-PCR, no immunostaining was found for lamins, neither in the follicle cells nor in the oocytes.

An immunohistochemical study of ovarian follicle histogenesis in the early post-hatch Japanese quail (Coturnix coturnix japonica)

The early post-hatch development of immunoreactivity to vimentin, desmin, smooth muscle actin (SMA) and laminin, in relation to follicle histogenesis, was described in this study. Ovigerous cords in day old quails contained pre-granulosa cells and oocytes. Pre-granulosa cells at the cortico-medullary junction were vimentin immunopositive. A laminin immunopositive basement membrane and desmin immunopositive mesenchymal cells lined the ovigerous cords. Ovigerous cords in 3-day-old quails contained developing primordial follicles, the vimentin immunopositive pre-granulosa cells of which were partially encircled by a basement membrane and desmin immunopositive mesenchymal cells. In 5- to 7-day-old quails, ovigerous cords formed an outer cortical region, while primordial follicles formed the inner cortical region. Early pre-vitellogenic follicles were present in 9- to 13-day-old quails. Underlying the granulosa cells of these follicles was a laminin immunopositive basement membrane and a layer of desmin immunopositive thecal cells. Early and late pre-vitellogenic follicles dominated the ovary in 15- to 17-day-old quails. The thecal layer in these follicles was desmin immunopositive, but SMA immunonegative. The results of the study have shown that the process of primordial follicle development in the Japanese quail is similar to that reported in mammals. The study suggests that in the quail pre-granulosa cells originate predominantly from the medulla. The study has shown that, in the Japanese quail, thecal cells are derived from desmin immunopositive mesenchymal cells lining the ovigerous cords.

The immunohistochemical localization of desmin and smooth muscle actin in the ovary of the African giant rat (Cricetomys gambianus) during the oestrous cycle

The aim of this study was to describe the distribution of smooth muscle actin and desmin immunopositive cells in the ovary of the giant rat. In addition, the study describes the morphological changes in the ovary of this species during the oestrous cycle. Healthy secondary and tertiary follicles dominated the ovary during pro-oestrus and oestrus. The theca externa of the tertiary follicles was immunopositive for smooth muscle actin, but immunonegative for desmin. Oestrus was also characterized by the presence of corpora haemorrhagica, which had an outer layer of smooth muscle actin immunopositive cells. Differentiating corpora lutea were observed during metoestrus. A further notable feature of the ovary during metoestrus was the presence of numerous atretic secondary and tertiary follicles. In the later stages of atresia, the follicles were infiltrated by desmin and smooth muscle actin immunopositive cells. Dioestrus was characterized by the presence of non-regressing and regressing corpora lutea. Immunostaining for smooth muscle actin was demonstrated in the enclosing layer of the corpora lutea, as well as in the tunica media of blood vessels within the corpora lutea. The results of this study have shown that morphological changes in the ovary of the giant rat during the oestrus cycle are similar to those of laboratory rodents. Furthermore, the results of the immunohistochemical study indicate that the perifollicular distribution of desmin and smooth muscle actin cells changes during follicular development and atresia.

Histological and Immunohistochemical Evaluation of Canine Ovary

In the present study, 15 canine ovaries without morphological lesions were examined histologically and immunohistochemically by using a large number of proteins including AE1/AE3, cytokeratin7 (CK7), CK13, CK20, vimentin, desmin, alpha smooth muscle actin (alphaSMA), calponin, S100, Neurofilaments, Inhibinalpha, placental alkaline phosphatase (PLAP) and neuron-specific enolase. Ovarian structures observed in this study included surface epithelium (SE), cortical tubules (CT), tunica albuginea (TA), stromal cells (SC), internal endocrine cells (IE), rete ovarii (RO) and fallopian tubes (FT). SE, CT, RO and FT were broadly immunoreactive for desmin. Besides AE1/AE3 and vimentin, desmin was also closely linked to these structures. Rete ovarii forming a reticular structure showed a positive reaction to S100. Surface epithelium was immunoreactive for PLAP at a significantly high level. In conclusion, these results indicate a specific segment of immunoreactivity as well as the broad range of immunoreactivity in canine ovary. The distinct patterns of immunoreactive for various kinds of proteins will play an important role in facilitating their identification and discrimination even in a normal canine ovary with a complex structure.

An immunohistochemical study of the distribution of intermediate filaments in the ovary of the emu (Dromaius novaehollandiae)

The immunohistochemical localization of the intermediate filaments desmin, vimentin and smooth muscle actin (SMA) in the ovary of the emu was described in the present study. The cortical region of the ovary contained developing and atretic primordial, pre-vitellogenic and vitellogenic follicles. Vimentin immunostaining was demonstrated in the granulosa cell layer of primordial, pre-vitellogenic and vitellogenic developing and atretic follicles. An interesting finding of the present study was the localization of SMA in fibroblasts located in the theca externa of late vitellogenic follicles. The presence of SMA in these fibroblasts suggests that they possess characteristics of smooth muscle cells.

Histomorphological and Immunohistochemical Characterization of Equine Granulosa Cell Tumours

Benign (n=33) and malignant metastasizing (n=1) granulosa cell tumours (GCTs) from 34 mares aged 3-21 years, and normal (control) ovaries from nine mares aged 3-10 years, were examined histologically and immunohistochemically (for inhibin alpha, glutathione S-transferase alpha [GSTalpha], c-erbB-2 oncoprotein [cerb], cytokeratin, vimentin, desmin and alpha-actin), the results being related where appropriate to clinical signs and endocrinological data. Availability permitting, serum samples from GCT-affected mares before and several weeks after ovariectomy were examined for the following hormones: oestradiol, progesterone and testosterone (by radioimmunoassay); and inhibin B (by a cross-reactive ELISA). Histological examination revealed that the GCTs were predominantly well differentiated neoplasms. The metastasizing GCT differed immunohistochemically from the benign GCTs in respect of the expression patterns of vimentin, cerb and GSTalpha in the granulosa cells. A notable feature was the presence of Leydig-like cells in mares with stallion-like behaviour or elevated serum testosterone, or both. GSTalpha immunolabelling indicated that the Leydig-like cells were potential producers of steroid hormone. From the immunohistochemical and endocrinological findings it was concluded that GCTs produce abnormally high concentrations of inhibin, which reduce the release of follicle-stimulating hormone, leading to atrophy of the contralateral ovary-a finding in 27 of the mares.

Microscopic characterization of follicular structures in letrozole-induced polycystic ovarian syndrome in the rat

BACKGROUND

Our objective was to characterize the tissular distribution of relevant cytoskeletal proteins, cellular adhesion molecules and proliferation markers and conduct a histomorphometrical study of the follicular wall of letrozole-induced polycystic ovaries.

METHODS

Twenty rats were divided into two groups: a control group (C) of ten rats that received vehicle only (0.9% NaCl solution) once daily p.o. and a treatment group (T) of ten animals administered letrozole at a concentration of 1 mg/kg p.o. dissolved in 0.9% NaCl solution once daily during 21 days. Twenty four h after the last administration, all animals were sacrificed. Control animals were sacrificed in proestrous (n = 5) and diestrous (n = 5). Serum hormone levels, histomorphometrical changes and immunoexpression of intermediate filaments (vimentin, cytokeratins and desmin), cadherins and proliferation cellular nuclear antigen were examined.

RESULTS

The granulosa cell layer of cystic follicles had a greater significant immunostaining for vimentin and cytokeratins. Immunohistochemical localization of desmin was restricted to the theca externa. Positive immunoreactivity for cadherins rises gradually and significantly, together with the follicular development, and immunoreactivity was comparatively stronger in follicular cysts. A significantly higher immunostaining for PCNA cells was observed in secondary and tertiary follicles as compared with atretic and cystic follicles. An increase in the LH, FSH and testosterone serum concentrations was observed in letrozole-treated rats. Estradiol and progesterone showed a considerable reduction.

CONCLUSIONS

The changes observed are probably due to structural and functional alterations that occur during the process of cystogenesis and may be associated with important modifications in the expression of cytoskeletal proteins, cellular adhesion molecules and proliferation markers that may be essential for proper cellular functioning.

Formation of mammalian oocytes and their growth, differentiation and maturation within ovarian follicles

The limited knowledge on the regulation of oocyte formation, the different steps of folliculogenesis and the required conditions for oocytes to undergo proper growth, differentiation and maturation are major causes of the failure in obtaining viable offspring from in vitro cultured early oocytes from domestic animals and humans. This review highlights the factors that at present are known to be involved in the formation of mammalian oocytes and their growth, differentiation and maturation within ovarian follicles.

Expression of Cytoskeletal Proteins in the Follicular Wall of Induced Ovarian Cysts

Several experimental models have been developed for the study of the polycystic ovarian syndrome in the rat. In the present study, the syndrome was induced by exposure to constant light, and the expression of cytoskeletal proteins in the follicular wall was evaluated by immunohistochemistry. We analyzed the immunohistochemically stained area (IHCSA) by image analysis to evaluate the expression of intermediate filaments (vimentin, desmin, cytokeratins, gliofibrillary acidic protein and neurofilaments) and alpha-smooth muscle actin (alpha-SMA) in cystic ovaries in relation to normal ovaries. The granulosa cell layer of cystic follicles had a significantly greater IHCSA for vimentin than the normal antral follicles. This difference was also significant between atretic and antral follicles. Cytokeratins showed a very low expression in the granulosa cells of antral follicles of control ovaries while in granulosa cells of atretic and cystic follicles they showed a significantly higher IHCSA. Immunohistochemical localization of desmin and alpha-SMA was restricted to the theca externa. Immunoreactivity for gliofibrillary acidic protein and neurofilament was negative. The highest intensity in the staining with vimentin and cytokeratins observed in the granulosa cells of the cystic follicles is probably due to structural and functional changes that occur during the process of cystogenesis and they could be associated with intense changes in the expression of cytoskeletal proteins that may be essential to the proper cellular functioning.

Demonstration of intermediate filaments in sheep ovary

Distribution patterns of intermediate filaments, vimentin, smooth muscle actin, and desmin were studied in the ovine ovary using an immunohistochemical method. Vimentin was consistently expressed in follicular cells of primary, secondary, and antral follicles. Stromal cells of cortex and medulla and those surrounding the corpus luteum were immunostained with the anti-vimentin antibody. Endothelial cells lining blood vessels showed strong anti-vimentin positivity. Smooth muscle cells positive for smooth muscle actin were incorporated in the cortical region in the theca interna and externa and formed incomplete spheres around large antral follicles. In atretic follicles, the presence of positive smooth muscle cells inside follicular spaces were related with capillaries. Corpora lutea were surrounded by a layer of positive smooth muscle cells. In the hilus, smooth muscle actin was localized in the wall of blood vessels. In cortical regions, desmin-positive cells were randomly distributed and occasionally formed ill-defined clusters around tertiary follicles, but not around secondary follicles, whereas desmin was expressed in the medullary region in blood vessels. The distribution pattern of intermediate filaments in sheep ovary suggests a possible role of smooth muscle cells in the mechanism of ovulation.

Expression of cytokeratins and vimentin in normal and neoplastic tissue from the bovine female reproductive tract

The distribution of cytokeratins (CKs) and vimentin in the normal genital tract of calves and cows at different stages of the oestrous cycle and in epithelial tumours of the tract was studied immunohistochemically. Few differences in CK and vimentin immunolabelling were detected in relation to age or stage of the oestrous cycle. Coexpression of CKs in simple epithelia and in basal cells of stratified epithelia was detected in the oviduct and endocervix; this coexpression was different from that previously described in women. The demonstration of CKs but not vimentin in the neoplastic cells of a serous superficial ovarian papilloma suggested an origin from the ovarian surface epithelium, while the coexpression of CKs and vimentin in serous papillary and mucinous cystadenomas pointed to a possible origin from the rete ovarii. Studies on three uterine adenocarcinomas and the ovarian metastases from two of these showed an endometrial-CK phenotype. The intermediate filament profile of normal endometrium, conserved in uterine adenocarcinomas and their ovarian metastases, may be useful in discriminating between ovarian metastases from endometrial carcinomas and those originating from primary carcinomas in other organs.

Structural and cell surface antigen expression in the rete ovarii and epoophoron differs from that in the Fallopian tube and in endometriosis

AIMS

We compared the immunohistochemical profiles of the rete ovarii and endometriosis in order to identify a panel which distinguishes between these structures. The immune profiles of the epoophoron, Fallopian tube and ovarian surface epithelium were also studied.

MATERIALS AND METHODS

Twenty-four women with no evidence of endometriosis and seven who had endometriosis in the uterine adnexae were studied using nine antibodies to intermediate filament proteins and cell surface markers. None of the structures studied shared an identical profile of immunohistochemical reaction. The immunoprofile of endometriosis showed some similarities to that of the Fallopian tube, but differed from that of the rete ovarii, epoophoron and ovarian surface epithelium

CONCLUSIONS

A panel including Ca-125, epithelial membrane antigen and the epithelial glycoprotein BerEp4 would permit the distinction between endometriosis and the rete ovarii in problematic cases. The study showed some commonality in reaction between endometriosis and the Fallopian tube which indicates that they may share a common (paramesonephric) origin. There was little commonality in the immunoprofile of endometriosis and the ovarian surface epithelium implying that endometriosis is unlikely to develop as a result of serosal metaplasia.

An immunohistochemical study of the rete ovarii and epoophoron

A study to compare the immuno-histochemical profile of the human rete ovarii, and epoophoron, with the Fallopian tube and ovarian surface epithelium was performed with 31 antibodies and antisera. A reaction was present in the epithelial cytoplasm of the rete ovarii and epoophoron of mesonephric origin, for vimentin, GFAP, cytokeratin markers, (AE1/AE3, MNF116; Cam 5.2, 34 beta E12 and for the monospecific antibodies to cytokeratins 7 and 19), heat shock protein 27, in the cell membrane for HBME-1, EMA and in the subepithelial collagen for collagen IV. Reactions were present only in the epithelium in the rete ovarii for EGFR (one case) and CA-125 (four cases). A reaction was present in the epithelium of the epoophoron only for Ber-EP-4 and S100. There was no reaction with antibodies for desmin, neurofilament protein, cytokeratins 20 or 14, actin, calretinin, E-cadherin, C-erb-B2, or CEA (monoclonal and polyclonal reagents). The immuno-histochemical profile of the Fallopian tube was consistent with its para-mesonephric origin and that in the ovarian surface epithelium was consistent with a proposed modified mesothelial origin. This study provides an immunohistochemical profile of these structures with a large panel of commonly available antibodies and antisera, confirming and extending the findings described in previous studies.

Ki-67, oestrogen receptor, and progesterone receptor proteins in the human rete ovarii and in endometriosis

AIM

To examine proliferative activity using the Ki-67 protein, oestrogen receptor protein, and progesterone receptor protein expression in the rete ovarii, and to make comparisons with their expression in endometriosis.

METHODS

Immunohistochemistry was used to study the rete ovarii in 24 cases and endometriosis in seven cases, using antibodies to Ki-67 protein (growth fraction (GF) quantified using a point score method) and oestrogen receptor and progesterone receptor (quantified using the H score method).

RESULTS

There was no evidence of a significant difference in the Ki-67 protein, oestrogen receptor, and progesterone receptor in the rete ovarii in different phases of the menstrual cycle (proliferative phase: GF = 1.052, oestrogen receptor H score = 13.4, progesterone receptor H score = 15.32; secretory phase: GF = 0.736, oestrogen receptor H score = 7.5, progesterone receptor H score = 1.84). The expression of all three proteins was greater in the foci of endometriosis (GF = 6.99, oestrogen receptor H score = 152.02, progesterone receptor H score = 127.36) than in the rete ovarii (p < 0.0005-0.0008, Mann-Whitney U test).

CONCLUSIONS

There is a low rate of cellular proliferation in the rete ovarii and this structure shows less responsiveness to hormone stimulation than foci of endometriosis. These differences may provide a useful tool to distinguish the rete ovarii from endometriosis in cases of diagnostic difficulty.

Patterns of keratins 8, 18 and 19 during gonadal differentiation in the mouse: sex- and time-dependent expression of keratin 19

The acidic keratins K18 and K19 have been shown to display a sex-specific expression during gonadal differentiation in the rat. To extend these findings, we have undertaken a study of the expression of genes encoding for K18 and K19 and their basic partner K8 in the mouse from 10.5 days of gestation until adulthood, using immunofluorescence, in situ hybridization, and reverse transcriptase polymerase chain reaction (RT-PCR). In the urogenital ridge at 10.5 days of gestation, K18, K19, and K8 are present, in both sexes, in coelomic epithelium in the area of the prospective gonad. At 11 days and 10 h of gestation, they are detected in differentiating gonadal blastema. In male gonads at 11 days and 16 h of gestation the first Sertoli cells differentiate. They are stained for anti-Müllerian hormone by immunofluorescence and appear as dispersed cells throughout the blastema. Progressively, they adhere to each other and form differentiating seminiferous cords. K19 disappears as Sertoli cells differentiate. K18 and K8 continue to be detected in Sertoli cells during fetal life and after birth until 14 days postpartum. In the adult testis, no keratin is observed. In differentiating ovaries, the three keratins are present in somatic cells of the ovigerous cords during fetal life and in primordial follicles differentiating from 1-2 days postpartum. In the course of follicular development, K19 is no longer detected as primordial follicles differentiate into growing follicles. K18 and K18 are present in all stages of follicular development. These results show both differences and similarities with the results previously obtained in the rat. In the mouse, in contrast to the rat, keratins are detected in adult ovaries, and K18 is found in undifferentiated gonads and in ovaries. K18 is, thus, not specific to the testis in the mouse, as it is in the rat. In both species, K19 ceases to be expressed in male gonads as Sertoli cells differentiate and form seminiferous cords. The present observations confirm that downregulation of K19 gene expression in the fetal testis is one of the earliest molecular events attesting the commitment of the undifferentiated gonad to the male differentiative pathway.