Molecular cloning, expression analysis, and function of decorin in goat ovarian granulosa cells

Single-cell analysis comparing early-stage oocytes from fresh and slow-frozen/thawed human ovarian cortex reveals minimal impact of cryopreservation on the oocyte transcriptome

STUDY QUESTION

Does the slow-freezing and thawing process have a negative impact on the transcriptome of oocytes isolated from early-stage human follicles compared to fresh controls?

SUMMARY ANSWER

The transcriptional profiles of fresh and frozen/thawed oocytes did not cluster separately, indicating undetectable differences between the two groups when compared to within-donor heterogeneity.

WHAT IS KNOWN ALREADY

Previous studies using histological analysis of follicle morphology, density, and stage distribution in slow-frozen/thawed human ovarian cortex compared to fresh controls showed no differences between the two groups. Clinical cases reported in the past 10 years have demonstrated that transplanted slow-frozen/thawed and fresh ovarian cortex restored normal serum FSH levels and regular menstrual cycles by 5 months. However, the slow-frozen and thawed tissue resulted in lower rates of pregnancies and live births, albeit not statistically significant.

STUDY DESIGN, SIZE, DURATION

We utilized single-cell RNA-sequencing (scRNAseq) of 144 human oocytes isolated from cadaver ovaries obtained from three donors.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human ovarian cortex from three healthy premenopausal donors 16, 18, and 27 years old was cut into squares measuring 10 × 10 × 1 mm3 and either slow-frozen and thawed or processed fresh. First, using a novel method for isolating live oocytes from primordial and primary follicles, the ovarian cortex squares were fragmented with a McIlwain tissue chopper and enzymatically digested. Next, oocytes were mechanically denuded under a dissection microscope and placed individually into wells containing lysis buffer for scRNAseq. Lysed single oocytes were subjected to library prep using the seqWell PlexWell rapid single-cell RNA protocol. Pooled libraries were subjected to 150-bp paired-end sequencing on the NovaSeq6000 Illumina platform. In total, we sequenced 144 oocytes-24 oocytes isolated fresh and 24 oocytes isolated after slow-freezing and thawing from each of the three donors. Additionally, we performed histological analysis of fresh and frozen/thawed ovarian cortex tissue from all three donors using hematoxylin and eosin staining and analyzed morphology, follicle density, and follicle stage distribution differences between fresh and cryopreserved ovarian cortex.

MAIN RESULTS AND THE ROLE OF CHANCE

The histological analysis revealed no differences in follicle stage distribution or follicle morphology between conditions, with the percentage of normal follicles in fresh and frozen/thawed tissue, respectively, as 86.7% and 91.0% for Donor 1, 91.7% and 92.5% for Donor 2, and 96.1% and 91.1% for Donor 3. The follicle density per mm3 in fresh and frozen/thawed tissue, respectively, was 279.4 and 235.8 for Donor 1, 662.2 and 553.5 for Donor 2, and 55.8 and 71.4 for Donor 3. The difference in follicle density was not statistically significant between fresh and frozen/thawed conditions for Donors 2 and 3, and significant (P = 0.017) for Donor 1. The stromal cell densities in fresh and frozen/thawed tissue, respectively, were 0.014 in both conditions for Donor 1, 0.014 and 0.016 for Donor 2, and 0.013 and 0.014 for Donor 3. There was no statistically significant difference in stromal cell density between conditions in Donor 1 and Donor 3, though it was statistically significant (P ≤ 0.001) for Donor 2. The transcriptional profiles of fresh and frozen/thawed oocytes did not cluster separately, suggesting insignificant differences between the two groups. However, at the group mean level, there was a small shift between the fresh and frozen/thawed oocytes and the shifts were parallel across the three donors. In this comparison, fresh oocytes were enriched for gene ontology terms related to chromosome segregation and mitosis, whereas frozen/thawed oocytes were enriched for terms related to wound response, cAMP signaling, and extracellular matrix organization.

LARGE SCALE DATA

Datasets available on Zenodo.org. DOI: https://zenodo.org/records/13224872.

LIMITATIONS, REASONS FOR CAUTION

In this study, we only sequenced the oocytes isolated from early-stage follicles due to technical challenges collecting and sequencing the somatic cells surrounding the oocytes. Investigating the transcriptomic changes after freezing and thawing in the somatic cells would need to be studied in the future. Additionally, we built RNAseq libraries immediately after thawing focusing on the immediate changes. Investigation of the effects that manifest at later timepoints, either in culture or upon implantation in an animal model, may reveal additional effects of the freeze/thaw process on the transcriptome.

WIDER IMPLICATIONS OF THE FINDINGS

The only clinically approved method of fertility preservation for prepubertal cancer patients and adult patients who cannot delay cancer treatment is ovarian tissue cryopreservation. Investigation of cryopreservation-induced changes in follicles at all stages is critical to further our understanding of the safety and efficacy of using these tissues for fertility preservation in the clinic. Our study is the first to analyze transcriptomic changes between individual fresh and slow-frozen/thawed human oocytes collected from early-stage follicles. To accomplish this, we developed a novel method for dissociating both fresh and frozen/thawed human ovarian cortex to obtain live denuded oocytes from early-stage follicles. Our findings provide insights into the use of cryopreserved tissue and follicles for fertility preservation efforts.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by National Institutes of Health (NIH) R01HD099402, Career Training in Reproductive Biology (CTRB) Training Grant National Institutes of Health (NIH) T32 to Jordan Machlin, National Institutes of Health (NIH) F31-HD106626 and National Institutes of Health (NIH) T31H-D079342 to Andrea Jones, National Institutes of Health (NIH) T32-GM70449 to D. Ford Hannum, and The Chan Zuckerberg Initiative Grant CZF2019-002428. We have no conflicts of interest to declare.

Spatiotemporal transcriptomic changes of human ovarian aging and the regulatory role of FOXP1

Limited understanding exists regarding how aging impacts the cellular and molecular aspects of the human ovary. This study combines single-cell RNA sequencing and spatial transcriptomics to systematically characterize human ovarian aging. Spatiotemporal molecular signatures of the eight types of ovarian cells during aging are observed. An analysis of age-associated changes in gene expression reveals that DNA damage response may be a key biological pathway in oocyte aging. Three granulosa cells subtypes and five theca and stromal cells subtypes, as well as their spatiotemporal transcriptomics changes during aging, are identified. FOXP1 emerges as a regulator of ovarian aging, declining with age and inhibiting CDKN1A transcription. Silencing FOXP1 results in premature ovarian insufficiency in mice. These findings offer a comprehensive understanding of spatiotemporal variability in human ovarian aging, aiding the prioritization of potential diagnostic biomarkers and therapeutic strategies.

Identification and characterization of unique and common lncRNAs and mRNAs in the pituitary, ovary, and uterus of Hu sheep with different prolificacy

LncRNAs are regarded as regulators in various animal reproductive physiological processes. However, the regulation of lncRNAs in the reproductive organ development of Hu sheep with different prolificacy remains unknown. Herein, numerous tissue-unique and -common differentially expressed lncRNAs (DELs) and differentially expressed genes (DEGs), and fecundity-unique DELs and DEGs were identified among different comparison groups at horizontal and vertical levels. Moreover, the tissue-unique and -common, and fecundity-unique female reproduction-associated DEGs and DELs were screened, and the interaction networks were constructed. Furthermore, MSTRG.43442.1 was mainly present in the cytoplasm of tested cells. The key genes ADAMTS1 and DCN were mainly localized in the granulosa cells, pituitary cells and/or endometrial epithelial cells of ovary, pituitary and/or uterus. Overall, this study identified large numbers of unique and common DELs and DEGs in the female reproductive organs of Hu sheep with different prolificacy and provided new insights into understanding the regulation of Hu sheep fecundity.

A Proteomic Study of the Effect of N-acetylcysteine on the Regulation of Early Pregnancy in Goats

Simple Summary

Early pregnancy regulation is an extremely complex process that is influenced by various factors. We previously mined the differentially expressed genes affected by N-acetyl-L-cysteine (NAC) in early pregnancy in goats via transcriptome sequencing. We found that NAC increased the number of lambs by affecting the immune pathway in ewes and enhancing antioxidation. Based on this, we here explored the effect of NAC on early pregnancy in goats at the protein level. The results showed a difference in the expression of uterine keratin and increases in the levels of antioxidant indices and hormones in doe serum.

Abstract

Dietary supplementation with N-acetyl-L-cysteine (NAC) may support early pregnancy regulation and fertility in female animals. The purpose of this study was to investigate the effect of supplementation with 0.07% NAC on the expression of the uterine keratin gene and protein in Qianbei-pockmarked goats during early pregnancy using tandem mass spectrometry (TMT) relative quantitative proteomics. The results showed that there were significant differences in uterine keratin expression between the experimental group (NAC group) and the control group on day 35 of gestation. A total of 6271 proteins were identified, 6258 of which were quantified by mass spectrometry. There were 125 differentially expressed proteins (DEPs), including 47 upregulated and 78 downregulated proteins, in the NAC group. Bioinformatic analysis showed that these DEPs were mainly involved in the transport and biosynthesis of organic matter and were related to the binding of transition metal ions, DNA and proteins and the catalytic activity of enzymes. They were enriched in the Jak-STAT signalling pathway, RNA monitoring pathway, amino acid biosynthesis, steroid biosynthesis and other pathways that may affect the early pregnancy status of does through different pathways and thus influence early embryonic development. Immunohistochemistry, real-time quantitative PCR and Western blotting were used to verify the expression and localization of glial fibrillary acidic protein (GFAP) and pelota mRNA surveillance and ribosomal rescue factor (PELO) in uterine horn tissue. The results showed that both PELO and GFAP were localized to endometrial and stromal cells, consistent with the mass spectrometry data at the transcriptional and translational levels. Moreover, NAC supplementation increased the levels of the reproductive hormones follicle-stimulating hormone (FSH), luteinizing hormone (LH), oestradiol (E2), progesterone (P4), superoxide dismutase (SOD), glutamate peroxidase (GSH-Px) and nitric oxide (NO) in the serum of does. These findings provide new insight into the mechanism by which NAC regulates early pregnancy and embryonic development in goats.

CYP19A1 May Influence Lambing Traits in Goats by Regulating the Biological Function of Granulosa Cells

Simple Summary

Aromatase (CYP19A1), a member of the cytochrome family, is widely expressed in ovarian and granulosa cells and is primarily responsible for the conversion of androgens to estrogens. Increased expression of CYP19A1 in follicular granulosa cells has implications for cell proliferation, steroid hormone secretion, and the expression of related functional indicator genes. We hypothesize that CYP19A1 may indirectly influence lambing numbers in goats by regulating follicular cell growth and development, as well as ovarian ovulation.

Abstract

Abnormal expression of CYP19A1, a gene related to steroid hormone synthesis, causes steroid hormone disruption and leads to abnormal ovulation in granulosa cells. However, the exact mechanism of CYP19A1 regulation is unclear. In this study, we confirmed the localization of CYP19A1 in goat ovarian tissues using immunohistochemistry. Subsequently, we investigated the effects of CYP19A1 on granulosa cell proliferation, steroid hormone secretion, and expression of candidate genes for multiparous traits by overexpressing and silencing CYP19A1 in goat granulosa cells (GCs). The immunohistochemistry results showed that CYP19A1 was expressed in all types of follicular, luteal, and granulosa cells, with subcellular localization results revealing that CYP19A1 protein was mainly localized in the cytoplasm and nucleus. Overexpression of CYP19A1 significantly increased the mRNA levels of CYP19A1, FSHR, and INHBA, which are candidate genes for multiple birth traits in goats. It also promoted cell proliferation, PCNA and Cyclin E mRNA levels in granulosa cells, and secretion of estrogen and progesterone. However, it inhibited the mRNA levels of STAR, CYP11A1, and 3βSHD, which are genes related to steroid synthesis. Silencing CYP19A1 expression significantly reduced CYP19A1, FSHR, and INHBA mRNA levels in granulosa cells and inhibited granulosa cell proliferation and PCNA and Cyclin E mRNA levels. It also reduced estrogen and progesterone secretion but enhanced the mRNA levels of STAR, CYP11A1, and 3βSHD. CYP19A1 potentially influenced the lambing traits in goats by affecting granulosa cell proliferation, hormone secretion, and expression of candidate genes associated with traits for multiple births.

Decorin: a multifunctional proteoglycan involved in oocyte maturation and trophoblast migration

Decorin (DCN) is a proteoglycan belonging to the small leucine-rich proteoglycan family. It is composed of a protein core containing leucine repeats with a glycosaminoglycan chain consisting of either chondroitin sulfate or dermatan sulfate. DCN is a structural component of connective tissues that can bind to type I collagen. It plays a role in the assembly of the extracellular matrix (ECM), and it is related to fibrillogenesis. It can interact with fibronectin, thrombospondin, complement component C1, transforming growth factor (TGF), and epidermal growth factor receptor. Normal DCN expression regulates a wide range of cellular processes, including proliferation, migration, apoptosis, and autophagy, through interactions with various molecules. However, its aberrant expression is associated with oocyte maturation, oocyte quality, and poor extravillous trophoblast invasion of the uterus, which underlies the occurrence of preeclampsia and intrauterine growth restriction. Spatiotemporal hormonal control of successful pregnancy should regulate the concentration and activity of specific proteins such as proteoglycan participating in the ECM remodeling of trophoblastic and uterine cells in fetal membranes and uterus. At the human feto-maternal interface, TGF-β and DCN play crucial roles in the regulation of trophoblast invasion of the uterus. This review summarizes the role of the proteoglycan DCN as an important and multifunctional molecule in the physiological regulation of oocyte maturation and trophoblast migration. This review also shows that recombinant DCN proteins might be useful for substantiating diverse functions in both animal and in vitro models of oogenesis and implantation.

Transcriptomic Profile of New Gene Markers Encoding Proteins Responsible for Structure of Porcine Ovarian Granulosa Cells

Simple Summary

The extracellular matrix (ECM) is involved in many physiological processes that occur in the ovary and affect reproduction in animals and humans. The ECM has been shown to significantly affect folliculogenesis, ovulation, and corpus luteum formation. This is mainly due to the involvement of ECM in intercellular signaling. In the present study, we report the gene expression profile of porcine granulosa cells during their primary in vitro culture. The genes presented are related to ECM formation but also to cadherins and integrins that influence intercellular dialogue. During the study, it was shown that most of the genes were upregulated. A detailed understanding of the expression of genes such as POSTN, CHI3L1, CAV-1, IRS1, DCN in in vitro culture of granulosa cells may provide a basis for further studies on the molecular mechanisms occurring within the ovary. Knowledge of ECM-related gene expression within granulosa cells can also be used to study the recently discovered stemness of these cells. Moreover, the presented data may serve for the development of assisted reproduction techniques, which, especially in vitro, are becoming increasingly common.

Abstract

The extracellular matrix (ECM) in granulosa cells is functionally very important, and it is involved in many processes related to ovarian follicle growth and ovulation. The aim of this study was to describe the expression profile of genes within granulosa cells that are associated with extracellular matrix formation, intercellular signaling, and cell–cell fusion. The material for this study was ovaries of sexually mature pigs obtained from a commercial slaughterhouse. Laboratory-derived granulosa cells (GCs) from ovarian follicles were cultured in a primary in vitro culture model. The extracted genetic material (0, 48, 96, and 144 h) were subjected to microarray expression analysis. Among 81 genes, 66 showed increased expression and only 15 showed decreased expression were assigned to 7 gene ontology groups “extracellular matrix binding”, “extracellular matrix structural constituent”, “binding, bridging”, “cadherin binding”, “cell adhesion molecule binding”, “collagen binding” and “cadherin binding involved in cell-cell adhesion”. The 10 genes with the highest expression (POSTN, ITGA2, FN1, LAMB1, ITGB3, CHI3L1, PCOLCE2, CAV1, DCN, COL14A1) and 10 of the most down-regulated (SPP1, IRS1, CNTLN, TMPO, PAICS, ANK2, ADAM23, ABI3BP, DNAJB1, IGF1) were selected for further analysis. The results were validated by RT-qPCR. The current results may serve as preliminary data for further analyses using in vitro granulosa cell cultures in assisted reproduction technologies, studies of pathological processes in the ovary as well as in the use of the stemness potential of GCs.

Cathepsin D knockdown regulates biological behaviors of granulosa cells and affects litter size traits in goats

Cathepsin D (CTSD), the major lysosomal aspartic protease that is widely expressed in different tissues, potentially regulates the biological behaviors of various cells. Follicular granulosa cells are responsive to the increase of ovulation number, hence indirectly influencing litter size. However, the mechanism underlying the effect of CTSD on the behaviors of goat granulosa cells has not been fully elucidated. This study used immunohistochemistry to analyze CTSD localization in goat ovarian tissues. Moreover, western blotting was applied to examine the differential expression of CTSD in the ovarian tissues of monotocous and polytocous goats. Subsequently, the effects of CTSD knockdown on cell proliferation, apoptosis, cell cycle, and the expression of candidate genes of the prolific traits, including bone morphogenetic protein receptor IB (BMPR-IB), follicle-stimulating hormone (FSHR), and inhibin α (INHA), were determined in granulosa cells. Results showed that CTSD was expressed in corpus luteum, follicle, and granulosa cells. Notably, CTSD expression in the monotocous group was significantly higher than that in the polytocous group. In addition, CTSD knockdown could improve granulosa cell proliferation, inhibit cell apoptosis, and significantly elevate the expression of proliferating cell nuclear antigen (PCNA) and B cell lymphoma 2 (Bcl-2), but it lowered the expression of Bcl-2-associated X (Bax) and caspase-3. Furthermore, CTSD knockdown significantly reduced the ratios of cells in the G0/G1 and G2/M phases but substantially increased the ratio of cells in the S phase. The expression levels of cyclin D2 and cyclin E were elevated followed by the obvious decline of cyclin A1 expression. However, the expression levels of BMPR-IB, FSHR, and INHA clearly increased as a result of CTSD knockdown. Hence, our findings demonstrate that CTSD is an important factor affecting the litter size trait in goats by regulating the granulosa cell proliferation, apoptosis, cell cycle, and the expression of candidate genes of the prolific trait.

lncRNA FDNCR promotes apoptosis of granulosa cells by targeting the miR-543-3p/DCN/TGF-β signaling pathway in Hu sheep

Long non-coding RNAs (lncRNAs) regulate the development of follicles and reproductive diseases, but the mechanisms by which lncRNAs regulate ovarian functions and fertility remain elusive. We profiled the expression of lncRNAs in ovarian tissues of Hu sheep with different prolificacy and identified 21,327 lncRNAs. Many of the lncRNAs were differentially expressed in different groups. We further characterized an lncRNA that was predominantly expressed in the ovaries of the low prolificacy Fec^B+ (LPB+) group and mainly present in granulosa cells (GCs), and the expression of this lncRNA decreased during follicular development, which we named follicular development-associated lncRNA (FDNCR). Next, we found that FDNCR directly binds miR-543-3p, and decorin (DCN) was identified as a target of miR-543-3p. FDNCR overexpression promoted GC apoptosis through increased expression of DCN, which could be attenuated by miR-543-3p. Furthermore, miR-543-3p increased and FDNCR reduced the expression of transforming growth factor-β (TGF-β) pathway-related genes, including TGF-β1 and inhibin beta A (INHBA), which were upregulated upon DCN silencing. Our results demonstrated that FDNCR sponges miR-543-3p in GCs and prevents miR-543-3p from binding to the DCN 3′ UTR, resulting in DCN transactivation and TGF-β pathway inhibition and promotion of GC apoptosis in Hu sheep. These findings provide insights into the mechanisms underlying prolificacy in sheep.

Zearalenone exposure triggered porcine granulosa cells apoptosis via microRNAs-mediated focal adhesion pathway

Zearalenone (ZEA), a metabolite of Fusarium, which is commonly found in moldy feed crops, is a well-known exogenous endocrine disruptor and has serious negative effects on animal reproduction. In order to understand the toxic effects of ZEA exposure on porcine granulosa cells (pGCs), which were exposed to 10 μM and 30 μM ZEA for 48 h in vitro, several methods were used for analysis. Flow cytometry and TUNEL analysis showed that the apoptosis of pGCs significantly increased in a dose-dependent manner after ZEA exposure compared with that of the control group. Whole transcriptome RNA-seq analysis was performed to reveal the mRNAs and miRNAs expression changes of pGCs after ZEA exposure and it was found that the expression of apoptosis-related genes was altered after ZEA exposure, and miRNAs were also significantly different among the experimental groups. In particular, ZEA exposure affected the expression of miRNAs associated with apoptosis-related pathways, such as miR-744, miR-1343 and miR-331-3p, as well as focal adhesion pathways related genes, Pak4 and Elk1, which were also involved in the apoptosis-related pathways. Moreover, the regulation networks between apoptosis-related mRNA and miRNAs were confirmed with the results of RT-qPCR and immunofluorescence. In conclusion, our results here demonstrated that ZEA exposure impaired pGCs growth and apoptosis via miRNAs-mediated focal adhesion pathway.

Elucidating Decorin's role in the preovulatory follicle

Background

DCN (decorin) is a proteoglycan known to be involved in regulating cell proliferation, collagen fibril organization and migration. In our global transcriptome RNA-sequencing approach to systematically identify new ovulation-associated genes, DCN was identified as one of the highly regulated genes. We therefore hypothesize that DCN may have a role in ovulatory processes such as cell migration and proliferation.

Aim

To characterize the expression, regulation and function of the proteoglycan DCN in the human ovarian follicles during the preovulatory period.

Methods

The in-vivo expression of DCN mRNA in mural (MGCs) and cumulus (CGCs) granulosa cells was characterized using quantitative RT-PCR and western blot.

A signaling study was performed by treating human MGCs cultures with gonadotropins and different stimulators and inhibitors to determine their effect on DCN expression by qRT- PCR and elucidate the pathways regulating these proteins.

In a functional study, KGN granulosa cell line was used to study cell migration with a scratch assay.

Results

DCN mRNA expression was significantly higher in MGCs compared to CGCs. DCN mRNA was significantly higher in CGCs surrounding mature metaphase II (MII) oocytes compared to CGCs of germinal vesicle (GV) and metaphase I (MI) oocytes.

hCG significantly increased DCN mRNA and protein expression levels in cultured MGCs. Using signal transduction activators and inhibitors, we demonstrated that DCN induction by LH/hCG is carried out via PKA, PKC, ERK/MEK, and PI3K pathways.

We showed that DCN expression is also induced in high-density cell cultures, in a dose-dependent pattern. In addition, progesterone induced a significant increase in DCN secretion to the media. MGCs from follicles of endometriosis patients exhibited reduced (about 20% of) mRNA transcriptions levels compared to MGCs follicles of control patients. More significantly, we found that DCN has an inhibiting effect on KGN cell migration.

Conclusions

Our study indicates that DCN is a unique ovulatory gene.

Our findings support the hypothesis that DCN plays an important new role during the preovulatory period and ovulation, and stress its involvement in endometriosis infertility. A better understanding of DCN role in ovulation and endometriosis may provide treatment for some types of infertility.

Chi-miR-4110 promotes granulosa cell apoptosis by targeting Sma- and Mad-related protein 2 (Smad2) in the caprine ovary

Follicular atresia mainly results from the apoptosis of granulosa cells (GCs). Whilst our previous investigations examined the role of chi-miR-4110 in regulating ovarian function, the present study detected the role of chi-miR-4110 in GC development. We transfected caprine GCs cultured in vitro with chi-miR-4110 mimics. Results revealed that chi-miR-4110 decreased mRNA and protein levels of Smad2 by targeting its 3'-untranslated region (3'UTR). FoxC1 and Sp1 mRNA and protein levels markedly increased, whereas those of bHLHe22 significantly decreased (P<0.01 or 0.05) in GCs transfected with the chi-miR-4110 mimics. Further studies revealed a significantly higher number of apoptotic cells in GCs transfected with the chi-miR-4110 mimics (P< 0.05) than in GCs transfected with mimics negative control. GCs transfected with the chi-miR-4110 mimics exhibited significantly increased mRNA and protein levels of the pro-apoptotic gene Bax (P<0.01) and significantly decreased expression levels of the anti-apoptotic gene BCL-2 (P<0.01). Smad2 interference (Si-1282) results were consistent with those of the chi-miR-4110 mimics. Previous reports and our results showed that chi-miR-4110 increases Sp1 expression by repressing Smad2. The increase in Sp1 induces p53-upregulated modulator of apoptosis, which increases the relative abundance of Bax and causes caprine GC apoptosis. Our findings may provide relevant data for the investigation of miRNA-mediated regulation of ovarian functions.