Presence of stem cell factor in follicular fluid and its expression in the human ovary

Synthetic human gonadal tissues for toxicology

The process of mammalian reproduction involves the development of fertile germ cells in the testis and ovary, supported by the surrounders. Fertilization leads to embryo development and ultimately the birth of offspring inheriting parental genome information. Any disruption in this process can result in disorders such as infertility and cancer. Chemical toxicity affecting the reproductive system and embryogenesis can impact birth rates, overall health, and fertility, highlighting the need for animal toxicity studies during drug development. However, the translation of animal data to human health remains challenging due to interspecies differences. In vitro culture systems offer a promising solution to bridge this gap, allowing the study of mammalian cells in an environment that mimics the physiology of the human body. Current advances on in vitro culture systems, such as organoids, enable the development of biomaterials that recapitulate the physiological state of reproductive organs. Application of these technologies to human gonadal cells would provide effective tools for drug screening and toxicity testing, and these models would be a powerful tool to study reproductive biology and pathology. This review focuses on the 2D/3D culture systems of human primary testicular and ovarian cells, highlighting the novel approaches for in vitro study of human reproductive toxicology, specifically in the context of testis and ovary.

Differentiation of human menstrual blood-derived endometrial mesenchymal stem cells into oocyte-like cells

Human endometrial mesenchymal stem cells (EnSCs) derived from menstrual blood are a unique stem cell source. Evidence suggests that EnSCs exhibit a multi-lineage potential and have attracted extensive attention in regenerative medicine. However, the potential of EnSCs to differentiate into germline cells in vitro remains unclear. In this study, EnSCs were induced to differentiate into germ cells in a differentiation medium supplemented with 20% human follicular fluid. Our results demonstrated that EnSCs derived from human menstrual blood form oocyte-like cells and express germ cell markers. The induced cell aggregates contained not only oocyte-like structures but also cells expressing follicle stimulating hormone receptor and luteotropic hormone receptor, and produced estrogen and progesterone regulated by gonodatropin, suggesting that granulosa-like and theca-like cells were also induced. We further found that granulosa cells promote the development of oocyte-like cells and activate the induction of blastocyst-like structures derived from EnSCs. In conclusion, EnSCs may potentially represent an in vitro system for the investigation of human folliculogenesis.

Human amniotic fluid stem cells have a potential to recover ovarian function in mice with chemotherapy-induced sterility

BACKGROUND

Human amniotic fluid cells (hAFCs) may differentiate into multiple cell lineages and thus have a great potential to become a donor cell source for regenerative medicine. The ability of hAFCs to differentiate into germ cell and oocyte-like cells has been previously documented. Herein we report the potential use of hAFCs to help restore follicles in clinical condition involving premature ovarian failure.

RESULTS

Human amniotic fluid was obtained via amniocentesis, yielding a subpopulation of cloned hAFCs that was able to form embryoid bodies (EBs) and differentiate into three embryonic germ layers. Moreover, culture of EBs in medium containing human follicular fluid (HFF) or a germ cell maturation factor cocktail (FAC), expressed germ cells markers such as BLIMP1, STELLA, DAZL, VASA, STRA8, SCP3, SCP1, and GDF9. Furthermore, one cell line was grown from clone cells transfected with lentivirus-GFP and displaying morphological characteristics of mesenchymal cells, had the ability to restore ovarian morphology following cell injection into the ovaries of mice sterilized by intraperitoneal injection of cyclophosphamide and busulphan. Restored ovaries displayed many follicle-enclosed oocytes at all stages of development, but no oocytes or follicles were observed in sterilized mice whose ovaries had been injected with medium only (control). Notably, identification of GFP-labeled cells and immunostaining with anti-human antigen-specific antibodies demonstrated that grafted hAFCs survived and differentiated into granulosa cells which directed oocyte maturation. Furthermore, labeling of ovarian tissue for anti-Müllerian hormone expression, a functional marker of folliculogenesis, was strong in hAFCs-transplanted ovaries but inexistent in negative controls.

CONCLUSION

These findings highlight the possibility of using human amniotic fluid-derived stem cells in regenerative medicine, in particular in the area of reproductive health.

Effect of ovarian stimulation with recombinant follicle-stimulating hormone, gonadotropin-releasing hormone agonist and antagonists, on follicular fluid stem cell factor and serum urocortin 1 levels on the day of oocyte retrieval

PURPOSE

To compare the serum and follicular fluid (FF) concentrations of stem cell factor (SCF) as well as the serum urocortin 1 (UCN1) concentration in gonadotropin-releasing hormone antagonist (GnRH-ant) and gonadotropin-releasing hormone agonist (GnRH-a) protocols for controlled ovarian hyperstimulation (COH) in IVF patients.

METHODS

Follicular fluids and blood samples of 42 infertile women undergoing COH for IVF-embryo transfer with either GnRH agonist (n = 22) or GnRH antagonist (n = 20) protocols from 2010 to 2011 were collected during oocyte retrieval. SCF concentrations of serum and FF were assessed by sandwich enzyme immunoassay using ELISA Kit for SCF kid. Serum UCN1 concentration were measured using commercially available enzyme-linked immunosorbent assay.

RESULTS

Concentrations of serum UCN1, serum and FF SCF were similar in the two groups. The serum SCF levels correlated strongly with the follicular SCF levels (r = 0.770, p < 0.001). The mean implantation rate, biochemical and clinical pregnancy rate and live birth rate per cycle were also similar in the groups.

CONCLUSIONS

These observations suggest that there is no significant difference in follicular microenvironment in terms of SCF and UCN1 between agonist and antagonist protocols.

Circulating concentration of stem cell factor in serum of stimulated IVF patients

Stem cell factor (SCF) plays a major role in haematopoiesis and spermatogenesis, and possibly female fertility. This study investigated the role of changes in SCF concentrations in 74 assisted conception patients. In group 1 (n=74) SCF concentration was assessed in serum and follicular fluid (FF) on the day of follicular puncture (FP) and compared in serum and FF in response to ovarian stimulation between low (n=25), moderate (n=26) and high (n=14) responders. In group 2 (n=30) serum for SCF assessment was collected throughout the menstrual cycle until gestation. SCF concentration related to the number of follicles in serum and in FF decreased from low to moderate and high responders (P<0.001); pregnancy rates were 20.0%, 34.6% and 50.1%, respectively (P=0.05). SCF in serum increased from stimulation days 6-8 to 9-11 and peaked on the day of human chorionic gonadotrophin injection (P=0.03). The SCF concentrations dropped slightly on the day of FP, increased significantly to the day of pregnancy confirmation and reached highest concentration (P=0.02) during gestation. SCF is involved in follicle development and may be a predictor of IVF outcome.

Human ovarian theca cells in culture

Elucidating the regulation of androgen biosynthesis in ovarian theca cells is not only important for determining the mechanisms of regulation of estrogen biosynthesis throughout the menstrual cycle, but is also essential for understanding the pathogenesis of excess androgen biosynthesis and polycystic ovary syndrome (PCOS). Human theca cells in primary and long-term culture have provided model systems for examining theca cell differentiation as well as the mechanisms underlying basal and cAMP-regulated steroid biosynthesis at both the transcriptional and post-transcriptional level in normal and PCOS ovaries. Results of these studies are expected to lead to the identification of novel targets for clinical treatment of infertility and PCOS.

Paracrine effects of oocyte secreted factors and stem cell factor on porcine granulosa and theca cells in vitro

Oocyte control of granulosa and theca cell function may be mediated by several growth factors via a local feedback loop(s) between these cell types. This study examined both the role of oocyte-secreted factors on granulosa and thecal cells, cultured independently and in co-culture, and the effect of stem cell factor (SCF); a granulosa cell derived peptide that appears to have multiple roles in follicle development. Granulosa and theca cells were isolated from 2-6 mm healthy follicles of mature porcine ovaries and cultured under serum-free conditions, supplemented with: 100 ng/ml LR3 IGF-1, 10 ng/ml insulin, 100 ng/ml testosterone, 0-10 ng/ml SCF, 1 ng/ml FSH (granulosa), 0.01 ng/ml LH (theca) or 1 ng/ml FSH and 0.01 ng/ml LH (co-culture) and with/without oocyte conditioned medium (OCM) or 5 oocytes. Cells were cultured in 96 well plates for 144 h, after which viable cell numbers were determined. Medium was replaced every 48 h and spent medium analysed for steroids. Oocyte secreted factors were shown to stimulate both granulosa cell proliferation (P < 0.001) and oestradiol production (P < 0.001) by granulosa cells throughout culture. In contrast, oocyte secreted factors suppressed granulosa cell progesterone production after both 48 and 144 hours (P < 0.001). Thecal cell numbers were increased by oocyte secreted factors (P = 0.02), together with a suppression in progesterone and androstenedione synthesis after 48 hours (P < 0.001) and after 144 hours (P = 0.02), respectively. Oocyte secreted factors also increased viable cell numbers (P < 0.001) in co-cultures together with suppression of progesterone (P < 0.001) and oestradiol (P < 0.001). In granulosa cell only cultures, SCF increased progesterone production in a dose dependent manner (P < 0.001), whereas progesterone synthesis by theca cells was reduced in a dose dependent manner (P = 0.002). Co-cultured cells demonstrated an increase in progesterone production with increasing SCF dose (P < 0.001) and an increase in oestradiol synthesis at the highest dose of SCF (100 ng/ml). In summary, these findings demonstrate the presence of a co-ordinated paracrine interaction between somatic cells and germ cells, whereby oocyte derived signals interact locally to mediate granulosa and theca cell function. SCF has a role in modulating this local interaction. In conclusion, the oocyte is an effective modulator of granulosa-theca interactions, one role being the inhibition of luteinization.

Interleukin-8 gene and protein expression are up-regulated by interleukin-1beta in normal human ovarian cells and a granulosa tumor cell line

OBJECTIVE

To evaluate the expression, regulation, and role of interleukin (IL)-8 in human ovary.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

Sixteen premenopausal women.

INTERVENTION

Follicular fluid and granulosa lutein cells (GLCs) were collected during IVF cycles. Ovarian stromal and theca cells were obtained from women underwent surgery. KGN cells, the human granulosa cell tumor cell line, were also used.

MAIN OUTCOME MEASURES

The levels of IL-8 and IL-1beta in follicular fluid and IL-8 protein production were determined using ELISA. Interleukin-8 and IL-8 receptor gene expression in ovarian cells and the effect of IL-8 on the proliferation of stromal cells were determined. The expression of pIkappaB was evaluated by Western blot, and the effect of NF-kappaB inhibitor APDC was examined by Northern blot analysis and ELISA in KGN cells. The levels of IL-8 and IL-1beta in follicular fluid; each concentration and the volume showed a positive correlation. Reverse transcription polymerase chain reaction showed the presence of IL-8 mRNA in all ovarian cells. In contrast, IL-8 receptor mRNA was only detected in stromal cells. The expression of IL-8 in GLCs and KGN cells was increased by addition of IL-1beta and TNFalpha. Interleukin-8 increased the proliferation of ovarian stromal cells. The expression of pIkappaB in KGN cells was induced by IL-1beta, and the effects were reduced by APDC.

CONCLUSION(S)

Interleukin 8 induced by IL-1beta via activation of NF-kappaB in granulosa cells may have a role in the periovulatory period of follicular maturation.

Hepatocyte growth factor and stem cell factor involvement in paracrine interplays of theca and granulosa cells in the human ovary

OBJECTIVE

To examine gene expression of hepatocyte growth factor (HGF), the receptor for HGF, c-met, and the receptor for stem cell factor (SCF), c-kit, in the human ovary and to investigate the effects of HGF and SCF on the proliferation and function of granulosa and theca cells.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

Six premenopausal women.

INTERVENTION(S)

Follicular fluid and granulosa cells were collected during IVF cycles. Ovarian tissues were obtained from women who underwent surgery.

MAIN OUTCOME MEASURE(S)

Gene expression of HGF, c-met, and c-kit in the human ovary was determined.

RESULT(S)

Reverse-transcription polymerase chain reaction showed the presence of HGF and c-kit mRNA in the theca and stroma cells of the ovary, whereas c-met mRNA was observed in the granulosa, theca, and stroma cells. HGF increased the expression of SCF gene in granulosa cells, and SCF reciprocally increased the expression of HGF gene in theca cells. SCF stimulated the proliferation of theca cells. HGF stimulated progesterone production in granulosa cells.

CONCLUSION(S)

A positive feedback loop between theca cells and granulosa cells was identified that is mediated by HGF and SCF. HGF and SCF modulate the interplay between theca and granulosa cells by promoting cell proliferation and steroid hormone production.