P-460 SARS-CoV-2 infection of human ovarian cells: an in vitro model for the detection of the virus entry into the host cells

Study question

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can enter and actively infect human follicular and granulosa cells?

Summary answer

Follicular Granulosa (GCs) and Cumulus cells (CCs) are susceptible to SARS-CoV-2 infection that is able to reproduce.

What is known already

To enter host cells, SARS-CoV-2 uses Spike S1 subunit to bind the receptor angiotensin-converting enzyme2 (ACE2), S2 subunit is cleaved by the host transmembrane serine protease 2 (TMPRSS2) or by cathepsin L (CSTL) to produce unlocked, fusion-catalyzing viral forms. CD147 (BSG) has been proposed as an additional host receptor for SARS-CoV-2. Female fertility is strictly dependent on oocyte quality and competence. ACE2 is highly expressed in the human ovaries and in the stromal endometrial cells, as well as in GCs and oocytes. The expression of ACE2 strongly suggests that it is potentially at a high risk of SARS-CoV-2 infection.

Study design, size, duration

In order to analyze the presence of host receptors ACE2 and co-receptors TMPRSS2-CSTL and BSG and consequently the susceptibility of GCs and CCs to SARS-CoV2 infection. GCs and CCs were collected from about 25 patients undergoing IVF/ICSI cycles at the UOSA of Assisted Reproductive techniques, from March 2020 to October 2021 at the Center of Couple Sterility, Siena University Hospital.

Participants/materials, setting, methods

GCs and CCs were collected from women undergoing IVF cycle. GCs were recovered from the follicular fluid according to the procedure previously published. After oocyte denuding, CCs were isolated and both GCs and CCs co-cultured with SARS-CoV-2 then the supernatant was used to infect VERO6 Cells. Host factors and SARS-CoV2 expression/localization were confirmed by RT-PCR, Western blot and Immunofluorescence. SARS-CoV2 infection and its effect on GCs and CCs were evaluated by Transmission and Immuno-electron microscopy.

Main results and the role of chance

qRT-PCR analysis and WB showed that ACE2, TMPRSS2, BSG and CTSL transcripts were expressed in both GCs and CCs cells, even if at different levels. ACE2 transcript was significantly increased in the CCs (0.43 vs 0.15; p < 0.05) with respect to GCs; this datum is very interesting since CCs are the follicular cells able to establish intimate connections with the developing oocyte (e.g. gap junctions). Therefore, contrary to what can be assumed, human CCs cannot act as a barrier against virus entry into the oocyte. Coreceptor BSG and CTSL were the most expressed in GCs with respect to TMPRSS2, (0.7 vs 0.3 and 0.8 vs 0.4 respectively; p < 0.05). Ultrastructural evaluation of human GCs and CCs infected with SARS-CoV-2 was carried out at different time points post-infection (24h, 48h and 72h). Infected human GCs showed cell-associated virus-like particles, virions were approximately spherical, with a diameter outside the lipid bilayer ranging from 50-150 nm and ultrastructural characteristics consistent with those described for other coronaviruses. Complete virions were also observed inside the cytoplasm as single or small groups of particles, either dispersed or within large vesicles. Immunoelectron microscopy confirmed these particles as SARS-CoV2.

Limitations, reasons for caution

This is a human in vitro study, and we cannot predict all the implications in female fertility and related to the oocyte

Wider implications of the findings

We provide evidence in favor of SARS-CoV-2 infection in GCs and CCs, the ovarian somatic cells that support oocyte development and competence acquisition. The close relationship between oocytes and follicular cells raises the hypothesis that these cells may represent a vehicle for the oocyte SARS-CoV-2 infection

Trial registration number

Not applicable

P-801 Human endometrial Organoids (hEOs): a non invasive powerful tool to study receptivity and a step forward precision medicine in IVF

Study question

Organoids from menstrual blood (MB) can mimic human receptive endometrium?

Summary answer

This research provides a reliable and less invasive 3D endometrial model able to mimic the window of implantation (WOI).

What is known already

Investigating the physiology and function of the normal cycling endometrium is challenging due to its great individual variability. hEOs are considered a new step forward in precision medicine and a tool for the study of endometrial biology, associated diseases (i.e. endometriosis) and to understand the complex mechanism surrounding endometrium-embryo cross talk. During the WOI apical cytoplasmic protrusions traditionally called “pinopodes” are reported to be a specific marker of endometrial receptivity.Initially hypothesized to form at the sites of blastocyst attachment, pinopodes have typically been correlated with successful implantation and are strongly regulated by the ovarian steroid hormones.

Study design, size, duration

hEOs are usually obtained from endometrial biopsy, here a much less invasive source was employed. Menstrual blood (MB) retrieved by menstrual cups was processed to isolate epithelial (Ep) and stromal endometrial cells (hESC). hEOswere created to investigate the morphological changes occurring in vivo during the menstrual cycle, specifically at the WOI. For a proof of concept, we recruited five healthy volunteers from January 2021 to december 2022 signing an informed written consent for this study.

Participants/materials, setting, methods

All the participants provided written informed consent for the use of their MB samples. Female healthy volunteers received instruction for the use of menstrual cups. hEOs obtained from MB have been exposed to hormonal treatments to mimic the endometrial hormonal milieu typical of the proliferative and mid secretory phase of the menstrual cycle. Cultured hEOs were then observed in a Quanta 400 (FEI) scanning electron microscope (SEM).

Main results and the role of chance

In this study we succeeded to establish a reliable 3Dmodel using both Ep cells and hESC using a less invasive approach. The hEOs generated from the co-culture of these two types of cells were used to mimic the mid secretory phase. The expansion media has been supplemented with 10 − 8 M E2 + 10 − 6 M P4 and 50 mM cAMP. Treated hEOs have been cultured for 4 days; washed with PBS and fixed for 2 h at 4 °C in cold Karnovsky’s. Using Scanning electron Microscopy, we closely observed the luminal surface of hEOs in the proliferative phase. The inner side of Ep cells was characterized by the presence of pinopodes large 5-10 μm, apical plasma membrane of uterine epithelial cells protrusions, not present in unstimulated hEOs. Generally, during days 17-19 of the menstrual cycle, cellular bulging increases with the formation of small (1-2 μm) pinopodes. Their full development was reported to be present at day 20and is a specific marker of the WOI.

Limitations, reasons for caution

There are discrepancies in the literature regarding pinopode morphology on specific days of the cycle, and of course, these changes may vary between individuals. Further studies, comprising individuals undergoing IVF treatments should be explored.

Wider implications of the findings

Effective and reliable embryo implantation modeling is necessary to mimic the molecular event cascade that occurs in vivo. Pinopodes responds to stimuli, in particular to Progesterone, these findings can be used to calibrate hormonal treatments of women undergoing IVF.

Trial registration number

Not applicable

P-073 SARS-CoV2 infection in human testis and sperm: in vivo and in vitro studies

Study question

Can severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) enter somatic and germinal cells of human testis or ejaculated sperm, thus affecting male reproductive function?

Summary answer

This research provides a biological background of the potential route for infection of SARS-CoV-2 and may enable rapid deciphering of COVID-19-induced male-related reproductive disorders.

What is known already

Epidemiologic studies suggest a significant male sex susceptibility for severe COVID19 symptoms. SARS-CoV-2 is known to affect certain cell types based on their expression of angiotensin-converting enzyme 2 (ACE2) and Transmembrane serine protease2 (TMPRSS2). ACE2 makes available the binding site for the Spike protein of SARS-CoV-2. TMPRSS2 facilitates virus entry by cleaving the S antigen into S1 (the active binding site). Several studies reported the presence of ACE2 in Leydig and Sertoli cells as well as in germ cells from spermatogonia to spermatozoa. These data suggest that the human testis and gametes are a target for SARS-CoV-2.

Study design, size, duration

To address this question, we examined the gene expression profile of SARS-CoV-2-associated receptors and proteases (ACE2-TMPRSS2) as well as their protein expression and localization in testicular tissue of males undergoing diagnostic surgery and in sperm of healthy, normozoospermic donors referring to the Unit of Assisted Reproduction, Siena University Hospital, from April 2020 to January 2022.

Participants/materials, setting, methods

Assays were performed on tissue biopsies (n = 3) or on freshly ejaculated sperm of men (n = 6) undergoing routine semen analysis after granting informed consent. To this end, tissue biopsies and ejaculated sperm have been co-cultivated for 5-12h with infected VERO E6 cells. Immunoelectron microscopy, in situ hybridization, and highly sensitive digital droplet PCR analysis, have been used to assess if particles containing SARS-CoV- 2 antigens can be detected in testicular tissue or spermatozoa in vitro.

Main results and the role of chance

We carefully investigated the presence of the SARS-CoV-2 virus and the possible effect on male fertility, both at the molecular and ultrastructural levels. To elucidate the mechanisms underlying virus infection in germ cells and male gametes, we analyzed the expression of both ACE2 and TMPRSS2. Both genes are expressed in testes and ejaculated sperm, confirming the possibility that SARS-CoV2 can enter these cells. We also provided evidence of the expression of the corresponding proteins in both testis and sperm by immunofluorescence assays. The immunofluorescence staining of paraffin-embedded slices of testicular tissue with anti-ACE2 antibody revealed a strong signal in Leydig cells. However, ACE2 staining was also present in human Sertoli cells and was concentrated in the adluminal half of the cell, i.e. surrounding spermatocytes and spermatids.

The analysis of TRPMSS2 showed similar results. Indeed, this protease is localized mainly in the interstitium, at the level of Leydig cells. This is an intriguing datum, since, while Leydig cells may be considered as a high-risk cells because of the co-expression of TMPRSS2 and ACE2, germ cells may not be at increased risk of ACE2and TMPRSS2-mediated viral entry and spread, given the lack of co-expression in these testicular cell type.

Limitations, reasons for caution

The low number of analyzed samples may limit the statistical power of this study. Whether the SARS-CoV-2 infection change the gene expression profile of other SARS-CoV-2-associated proteases is under investigation

Wider implications of the findings

This validated RT-PCR assay allows reliable screening of SARS-CoV-2 in sperm, useful for investigating the presence of the virus in patients undergoing ART, as well as for explaining the molecular and cellular mechanisms related to the gender specificity of the more severe infection-related symptoms.

Trial registration number

Not applicable

P-089 Characterization of Epididymosomes and Prostasomes in Seminal Plasma of Infertile Males

Study question

Could Extracellular Vesicles such as Epididymosomes and Prostasomes be employed as a new tool to characterize the male fertility potential?

Summary answer

Extracellular vesicles (EVs) content represents a new approach to the discovery of novel molecular mechanisms involved in sperm cell maturation and acquisition of fertilizing ability.

What is known already

Cells throughout the reproductive tract release EVs that are sorted by the endosomal compartment. These vesicles attract great attention because they contain lipids, proteins, nucleic acids that have been shown to be transferred to maturing sperm cells. EVs in seminal plasma, such as epididymosomes and prostasomes, contribute about 3% of the total associated seminal plasma proteins and are recognized as being responsible for sperm maturation, positively influencing actual fertilization. Several studies have documented the proteomic profile of these vesicles, but little is known about their specific contribution to sperm maturation, motility and acquisition of fertilizing capacity.

Study design, size, duration

48 Caucasian males underwent semen evaluation at the IVF Unit, Siena University Hospital, from October 2020 to November 2021. According to seminal parameters (WHO,2010), they were divided into Normozoospermic (N; n = 18); OligoAsthenoTeratozoospermic (OAT; n = 15); Azoospermic (A; n = 15). We excluded patients with an intake of spermiotoxic drugs, smoking, alcohol, or drugs abuse. The mean age was 33 years; the BMI ranged between 18-25. All participants signed a written informed consent, approved by the ethics committee.

Participants/materials, setting, methods

EVs from seminal plasma were isolated by an in-house modified EvGAG®-polymer precipitation-based protocol and characterized for their size and morphology by Nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM), respectively. Full proteomic profiling of these vesicles was obtained by 2-D electrophoresis and mass spectrometry, and further investigations by functional Omics analysis by bioinformatic tools (as. Metacore, STRING). Gene expression was evaluated by digital PCR (ddPCR).

Main results and the role of chance

The present work highlights the impact of EVs on male fertility due to their ability to transport selected molecules to maturing sperm cells, thus providing a specific proteomic and transcriptomic profile based on their fertilizing capacity. Proteomic profiling of OAT and A vs N samples provided crucial information regarding differential protein expression, thus obtaining information on the correlation between the encapsulated content of EVs and sperm parameters.

The ddPCR analysis of specific genes encoding for proteins expressed differently among patients confirmed that EVs may not only be potential biomarkers for male infertility, but at the same time contribute as an important regulator of specific pathways concerning sperm cell modification through the male reproductive tract. Genes involved in sperm-egg binding and zona pellucida interactions were overexpressed in N compared to OAT and A. Congruent results were obtained for genes involved in sperm cell metabolism. Meanwhile, regarding the acquisition of motility, some genes were found overexpressed in the OAT groups compared to N, indicating that some proteins delivered by EVs have a negative impact on sperm cell motility and function.

Limitations, reasons for caution

This study represents a preliminary experiment. A confirmatory study on an enlarged number of samples is needed to provide more statistical strength by reducing the effect of inter-sample variability.

Wider implications of the findings

Seminal extracellular vesicles secreted along the male reproductive tract have been demonstrated to be involved in the process of sperm maturation and could represent a new appealing therapeutic and diagnostic tool in the field of human reproduction for male fertility/infertility.

Trial registration number

Not applicable

O-217 Bitter Taste Receptors expression in human follicular cells: new perspectives in female fertility

Study question

Bitter TasteReceptors (TAS2Rs)role in female reproductive system cells: potential implications in mechanisms underlying oocyte maturation and sperm-oocytes interaction.

Summary answer

TAS2Rs and genes involved in their transduction cascade are differentially expressed in granulosa (GCs)and cumulus cells(CCs).

What is known already

TASRs expression can be found also in extraoral location wherein their function appears less obvious. TASRs are reported to be involved in signal transduction cascade induced by chemotactic activation in spermatozoa and the expression of TAS2Rs in ejaculated human sperm has been demonstrated. The presence of these receptors in male reproductive system and in sperm gives cues to investigate their possible role in sperm-oocyte interaction. Functional implications have been collected indicating that taste receptors are also important to increase the number of highly fertilization-competent sperm cells within the female genital tract hypothesizing a role in the field of female reproduction.

Study design, size, duration

We enrolled for this study 30patients undergoing IVF cycles because of couple infertilityfrom June 2019 to October 2020at the UOSA of Assisted Reproductive techniques, Siena University Hospital(Italy).

Participants/materials, setting, methods

Female patients referring to UOSA of Assisted Reproductive techniques(median age 35 years) underwent a personalised controlled ovarian hyperstimulation protocol. After oocyte pickup, GCs were isolated from the follicular fluid through differential gradient. CCs were collected after oocytes denuding. TAS2Rs and genes involved in the transduction cascade elicited expression/localization in both GCs and CCs were confirmed by Droplet Digital PCR, western blot andimmunofluorescence.

Main results and the role of chance

For the first time, the expression and cellular localization of the TAS2Rs (TAS2R3, TAS2R4, TAS2R14, TAS2R19 and TAS2R43), their G-coupled proteins (GNAT1 orα-transducinandGNAT3 or α-gustducin) and enzymes involved in the transduction signal (PDE4A, TRPM5 and PLCB2)were demonstrated in the female reproductive system. Overall expression of TAS2Rs emerged higher in GCs than in CCs, confirming the specific molecular fingerprinting during differentiation of ovarian somatic cells. TAS2R14 is the most expressed gene in both GCs and CCs, this could account for its potential involvement in follicular cells physiology and/or for a key role of this receptor in fertilization, as supported by data showing TAS2R14 to be correlated with sperm progressive motility. We demonstrated a positive correlation in GCs between the expression of the TAS2Rs and GNAT3; interestingly, when each subset of TAS2Rs genes was correlated with the signaling gene, TAS2R14 emerged as the one with the higher correlation with GNAT3. Immunofluorescence showed different localization of TAS2Rs and their G-coupled proteins between GCs and CCs. Interestingly some of them presented some fluorescent granules, suggesting a possible involvement of proteins in membrane trafficking. Finally, results of G-coupled proteins western blot, revealed the higher expression of α-gustducin then α-transducin, confirming the gene expression.

Limitations, reasons for caution

All findings have to be validated in a larger cohort. Moreover, our data pave the way to the understanding of biological functions exerted by these receptors in the female reproductive tract.

Wider implications of the findings

Further studies might contribute to better understanding the physiologic role of taste receptorsfemale reproductive system. This should becrucial to clarify the role of these receptors in maturation or competence acquiring of oocytes, or also in sperm-oocytes attraction and recognition, crucial point in fertilization process

Trial registration number

Not applicable

P–026 Seminal plasma exosomes: a promising source of biomarkers for fertility evaluation

Study question

Do exosomes from seminal plasma have a role in male fertility?

Summary answer

Exosomes isolated from seminal plasma have a pivotal role during spermatogenesis and sperm maturation and may represent eligible biomarkers for male fertility/infertility.

What is known already

During their journey along the male reproductive tract, exosomes contained in seminal fluid are involved in the transfer of several molecules to the maturing sperm. Exosomes are extracellular vesicles (EVs) released by all the cells; they carry a cargo of nucleic acids, proteins and lipids. In the male genital tract, they are released at various levels and their composition differs between men of proven fertility and infertile male patients. Recent studies reported the proteomic profile of exosomes, revealing the presence of several proteins with a well know role in sperm maturation and fertilizing ability acquiring.

Study design, size, duration

This prospective study consisted of 36 Caucasian men; according to seminal parameters (WHO 2010) they were divided in normozoospermic (N; n = 12), oligoasthenoteratozoospermic (OAT: n = 12) and azoospermic (A; n = 12). Semen samples were collected between October 2020 and January 2021 at the Assisted Reproductive Unit, Siena University Hospital (Italy) after institutional ethical approval and signed written consent from all the participants.

Participants/materials, setting, methods

Ejaculated sperm were analyzed according to WHO–2010 criteria and divided into the three groups: N, OAT and A. Exosomes were isolated by an in-house modified ExoGAG®-polymer precipitation-based protocol and characterized for size and ultrastructure by Nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The exosomal proteins were extracted and analyzed by 2D-electrophoresis and the identified profiles were examined by applying bioinformatic tools. The expression of selected genes was evaluated by digital droplets PCR (ddPCR).

Main results and the role of chance

The present work is readily providing an improvement of the standard ExoGAG® protocol and underlines its advantages over more conventional EVs isolation protocols used to date for recovery from seminal fluid: the number of recovered EVs and their size were finely included in the range of exosomes.

This isolation protocol provides samples suitable for proteomic analyses, representing the first 2D-electrophoresis reference map of exosome-pay loaded proteins in N respect to OAT/A groups and providing an innovative and comprehensive functional overview of its proteins. Moreover, the STRING protein-protein interaction analysis revealed the deregulation of specific pathways (e.g. signaling proteins, chromatin packaging and/or remodeling, protein folding and apoptosis) in A and OAT in comparison with N group.

Gene expression by ddPCR analysis highlighted that most of the analyzed genes are modulated in according to seminal parameters, in particular: GAPDHS (Glyceraldehyde–3-Phosphate Dehydrogenase, Spermatogenic); SPAM1 (Sperm Adhesion Molecule–1) encoding a members of hyaluronidase family; ADAM2 (ADAM Metallopeptidase Domain–2) that plays an important role in sperm-egg interactions; CRISP1,2,3 (Cysteine Rich Secretory Protein 1,2,3) expressed in the epididymis and secreted into the epididymal lumen; CLGN (Calmegin) encoding a testis-specific chaperone protein and PGK2 (Phosphoglycerate Kinase–2) expressed in the later stages of spermatogenesis.

Limitations, reasons for caution

This study represents a preliminary experiment. We suggest further comparative studies in larger study cohorts.

Wider implications of the findings: This pilot study, demonstrating the unique proteomic and transcriptomic pattern of exosomes in N/OAT/A groups, supports the importance of exosomes in sperm production and maturation. This methodological set-up is expected to open new ways for advancement in the use of exosomes as fertility biomarkers, making possible personalized approaches in ART.

Trial registration number

Not applicable

Metformin doses and body mass index: clinical outcomes in insulin resistant polycystic ovary syndrome women

OBJECTIVE

PCOS is the most common endocrinopathy among reproductive age women. Approximately 60% of PCOS women have insulin resistance. While the efficacy of metformin in reducing insulin resistance and decreasing androgen level has been widely validated, there is no agreement on the dose of metformin to be used.

PATIENTS AND METHODS

Prospective non-randomized cohort study of 108 insulin resistant, overweight and obese PCOS women, aged between 22 and 35 years. All patients received 1500 mg of metformin (500 mg x 3 times/day) for the first 6 months. At the end of this period, the patients' HOMA index was evaluated. In subjects, who did not demonstrate normalization of the HOMA index, the dose was increased to 2500 mg/day (500 mg at breakfast and 1000 mg at lunch and dinner) for additional 6 months. The hormonal blood profile, fasting insulin and fasting glucose levels, HOMA index, anthropometric assessment, pelvic ultrasound, FAI index and cholesterol were evaluated.

RESULTS

Overall results showed a good response to metformin therapy in insulin-resistant PCOS patients with BMI >25, while in patients with higher BMI (31.15 ± 0.40), no normalization of HOMA was found. At the higher dose of metformin, obese patients achieved a good response to therapy, with improvement in BMI, menstrual pattern, cholesterol levels and hyperandrogenism.

CONCLUSIONS

Our results demonstrate a correlation between the required dose of metformin, BMI and hyperandrogenism. The dose of metformin should be adjusted to patients' BMI in order to obtain significant results in terms of clinical, metabolic and hormonal responses.

Taste receptor polymorphisms and male infertility

STUDY QUESTION

Are polymorphisms of taste receptor genes associated with male infertility?

SUMMARY ANSWER

This study has showed the associations between three single nucleotide polymorphisms (SNPs) in taste receptors genes (TASR) and male infertility.

WHAT IS KNOWN ALREADY

Recent studies showed the expression of taste receptors in the testis and in spermatozoa, suggesting their possible role in infertility. The vast genetic variability in taste genes results in a large degree of diversity in various human phenotypes.

STUDY DESIGN, SIZE, DURATION

In this study, we genotyped 19 SNPs in 12 taste related genes in a total of 494 Caucasian male patients undergoing semen evaluation at the Centre of Couple Sterility of the Siena University Hospital. Consecutive patients were enrolled during infertility investigations from October 2014 to February 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Median age of the patients was 36 years (18-58) and 141 were smokers. Genotyping was performed using the allele-specific PCR. The statistical analysis was carried out using generalized linear model (GLM) to explore the association between age, smoking, the genetic polymorphisms and sperm parameters.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed that the homozygous carriers of the (G) allele of the TAS2R14-rs3741843 polymorphism showed a decreased sperm progressive motility compared to heterozygotes and (A) homozygotes (P = 0.003). Moreover, the homozygous carriers of the (T) allele of the TAS2R3-rs11763979 SNP showed fewer normal acrosome compared with the heterozygous and the homozygous carriers of the (G) allele (P = 0.002). Multiple comparisons correction was applied and the Bonferroni-corrected critical P-value was = 0.003.

LIMITATIONS, REASONS FOR CAUTION

The analysis is restricted to SNPs within genes and to men of Caucasian ancestry.

WIDER IMPLICATIONS OF THE FINDINGS

In silico analyses strongly point towards a functional effect of the two SNPs: TAS2R14-rs3741843 regulates TAS2R43 expression, a gene that is involved in cilia motility and therefore could influences sperm mobility; the (T) allele of TAS2R3-rs11763979 increases the expression of the WEE2 antisense RNA one gene (WEE2-AS1). According to Genotype-Tissue Expression (GTEx) project the WEE2 gene is expressed in the testes where presumably it has the role of down regulating meiotic cell division. It is plausible to hypothesize that the WEE2-AS1 increased expression may down regulate WEE2 which in turn can alter the natural timing of sperm maturation increasing the number of abnormal sperm cells.

STUDY FUNDING/COMPETING INTEREST(S)

None.

SA1/SA2 cohesion proteins and SIRT1-NAD+ deacetylase modulate telomere homeostasis in cumulus cells and are eligible biomarkers of ovarian aging

STUDY QUESTION

Are cohesins SA1/SA2 and the NAD-dependent deacetylase SIRT1 involved in telomere homeostasis of cumulus cells and thus eligible as biomarkers of follicular physiology and ovarian aging?

SUMMARY ANSWER

SA1/SA2 cohesins and SIRT1 are associated with telomere length in cumulus cells and may be eligible biomarkers of follicular physiology and ovarian aging.

WHAT IS KNOWN ALREADY

In somatic cells, cohesins SA1/SA2 mediate sister chromatid cohesion at the telomere termini (for SA1) and along chromatid arms (for SA2). The NAD+-dependent protein deacetylase Sirtuin 1 (SIRT1), which preserves DNA integrity from oxidative stress, may also modulate genome stability and telomere length.

STUDY DESIGN, SIZE, DURATION

Collectively 280 cumulus/oocyte complex samples were recovered from a total of 50 women undergoing in vitro fertilization.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cumulus cells were separated from the oocyte-cumulus complex. DNA and total mRNA were extracted from cumulus cells and assayed for telomere length and for SA1, SA2 and SIRT1 gene expression profiling. Telomere length was determined by quantitave PCR and analyzed relative to the single copy of the housekeeping gene (albumin) to generate a T/S ratio (Telomere/single copy gene). Gene expression levels of SA1, SA2 and SIRT1 mRNA were assayed by quantitative RT-PCR and confirmed by western blotting and immunofluorescent studies (SIRT1). SA1/SA2 and SIRT1 gene expression levels and telomere length analysis of patients/samples were ranked in relation to their clinical setting parameters (BMI, age) and to the number of oocyte retrieved.

MAIN RESULTS AND THE ROLE OF CHANCE

SA1 and SA2 transcripts were both detected in all cumulus cells analyzed and the relative amount showed a clear decreasing trend according to the age of patients. A significant increase in SA1 and SA2 was disclosed in high responder women (>6 oocytes retrieved) compared to poor responders (<4 oocytes) (P < 0.05). Furthermore, statistically significant positive correlations were also recorded between the transcripts levels of the two cohesin molecules (r = 0.89; P < 0.05) and, to a lesser extent, between telomere length and SA1 (r = 0.42; P < 0.001) and SA2 (r = 0.36; P < 0.001) mRNA levels. SIRT1 expression was also significantly increased in high responders (>6 oocytes) compared to poor responders. Significant correlations were found between SIRT1 and SA1 (r = 0.69; P < 0.001), between SIRT1 and SA2 (r = 0.78; P < 0.001), and between SIRT1 and telomere length (r = 0.36; P < 0.001). However, in the older patient group (>38 years), SIRT1 mRNA levels were twice as high as the levels recorded in the younger patient cohort (<34 years). Western blot analysis and immunofluorescent studies confirmed the increments in SIRT1 protein levels in patients over 38 years old.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Cumulus/oocyte complexes were retrieved by patients undergoing ovarian stimulation protocol for IVF. We cannot exclude the possibility that different stimulation protocols affect the correlations highlighted in this study. Future investigations should shed light on cumulus cells molecular profile according to different stimulation protocols.

WIDER IMPLICATIONS OF THE FINDINGS

The overall results of our study point to the involvement of cohesins SA1/SA2 and SIRT1 deacetylase in telomere homeostasis in cumulus cells and highlight their possible eligibility as biomarkers of follicular physiology and ovarian aging.

STUDY FUNDING/COMPETING INTEREST(S)

Merck Serono S.P.A Italy sponsored the study with financial support. There are no competing interests to declare.

Protein modification as oxidative stress marker in follicular fluid from women with polycystic ovary syndrome: the effect of inositol and metformin

PURPOSE

The purpose of this study was to evaluate the oxidative stress status (OS) of follicular fluid (FF) and the oocyte quality in women with polycystic ovary syndrome (PCOS) undergoing different ovarian stimulation protocols.

METHODS

FF samples were collected after gonadotropin administration in association or not with metformin or D-chiro-inositol (DCI). OS status was then evaluated by checking the follicular fluid protein oxidation profile after specific labeling of aminoacidic free-SH groups, and two-dimensional electrophoresis followed by qualitative and semiquantitative analysis. Oocyte quality was assessed by international morphological criteria.

RESULTS

Our data indicated that both treatments, even if to different extent, recovered a significantly high level of free-SH groups in FF proteins of PCOS women clearly indicating a decrease of OS level with respect to that found in FF samples from gonadotropins alone treated women. A higher number of good quality MII oocytes was also observed in DCI (P < 0.05) or metformin (P < 0.05) study groups in comparison to untreated control group.

CONCLUSION

A natural supplement and a drug both showed a statistically significant positive effect on follicular milieu by decreasing the oxidative damage on FF proteins, as well as in recovering good quality oocytes.

Galactosylceramidase deficiency causes sperm abnormalities in the mouse model of globoid cell leukodystrophy

The classical recessive mouse mutant, "the twitcher," is one of the several animal models of the human globoid cell leukodystrophy (Krabbe disease) caused by a deficiency in the gene encoding the lysosomal enzyme galactosylceramidase (GALC). The failure to hydrolyze galactosylceramide (gal-cer) and galactosylsphingosine (psychosine) leads to degeneration of oligodendrocytes and severe demyelination. Substrate for GALC is also the galactosyl-alkyl-acyl-glycerol (GalAAG), precursor of the seminolipid, the most abundant glycolipid in spermatozoa of mammals. In this paper, we report the pathobiology of the testis and sperm in the twitcher mouse and demonstrate the importance of GALC for normal sperm maturation and function. The GALC deficit results in accumulation of GalAAG in the testis of the twitcher mouse. Morphological studies revealed that affected spermatozoa have abnormally swollen acrosomes and angulation of the flagellum mainly at midpiece-principal piece junction. Multiple folding of the principal piece was also observed. Electron microscopy analysis showed that in the twitcher sperm, acrosomal membrane is redundant, detached from the nucleus and folded over. Disorganization and abnormal arrangements of the axoneme components were also detected. These results provide in vivo evidence that GALC plays a critical role in spermiogenesis.

Activation of Cell Cycle Regulatory Proteins in the Apoptosis of Terminally Differentiated Oligodendrocytes

There is increasing evidence that proteins normally involved in the cell cycle play a role in the regulation of neuronal apoptotic death following various insults. However, it is not clear if the same mechanisms regulate cell death of oligodendrocytes as well. In this study, we investigated the mechanism of ceramide-induced apoptosis in primary rat oligodendrocytes. We show that ceramide treatment initiates a cascade of biochemical events involving cell cycle regulatory proteins. Although at the time of induction of cell death the oligodendrocytes are postmitotic, activation of c-myc and translocation of Cdc25A into the nucleus can be demonstrated. Of particular interest are the findings of the up-regulation of PCNA and down-regulation of p21WAF1/CIP1 protein, an inhibitor of cell-cycle progression. The current results show that activation of regulatory cell-cycle proteins at the oligodendrocytes G1-S checkpoint may constitute a crucial step of the death pathway of oligodendrocytes.

Retrovirus-mediated gene transfer and galactocerebrosidase uptake into twitcher glial cells results in appropriate localization and phenotype correction

Galactocerebrosidase (GALC) is deficient in all tissues from human patients and animal models with globoid cell leukodystrophy (GLD) or Krabbe disease. The deficiency results in decreased lysosomal catabolism of certain galactolipids including galactosylceramide and psychosine that are synthesized maximally during myelination. According to current theories, the accumulation of psychosine in humans and animals with GLD induces oligodendrocyte degeneration and myelination ceases. Transduction of oligodendrocytes from twitcher mice with a retroviral vector containing the GALC cDNA can correct the enzyme deficiency in these cells. Our data show that twitcher astrocytes and oligodendrocytes can internalize exogenous GALC, as well as donate the enzyme to the mutant glial cells. Antibodies against human GALC localized the GALC antigen in retrovirally transduced cells and cells receiving enzyme via cell to cell secretion and uptake to the lysosomal fraction. In fact immunocytochemical studies in transduced oligodendrocytes revealed that the GALC colocalizes in vesicles lysosomal-associated membrane protein-2 (LAMP2) (+). Moreover, labeling cells with anti-GALC and a marker for oligodendrocytes demonstrated that, upon differentiation, transduced, twitcher oligodendrocytes attained the normal branched process configuration, while untransduced cells show only abnormal morphology. Phenotype correction in mutant oligodendrocytes has also been observed after enzyme transfer. These studies indicate that GALC activity supplied to cultured oligodendrocytes from twitcher mice by different methods can correct the pathological phenotype of these cells.

Transduction of cultured oligodendrocytes from normal and twitcher mice by a retroviral vector containing human galactocerebrosidase (GALC) cDNA

Krabbe disease or globoid cell leukodystropy is a lysosomal disorder caused by a deficiency of galactocerebrosidase (GALC) activity. This results in defects in myelin that lead to severe symptoms and early death in most human patients and animals with this disease. With the cloning of the GALC gene and the availability of the mouse model, called twitcher, it was important to evaluate the effects of providing GALC via a retroviral vector to oligodendrocytes in culture. After differentiation, the untransduced cells from normal mice extended highly branched processes while those from the twitcher mice did not. Oligodendrocytes in culture can be readily transduced to produce much higher than normal levels of GALC activity. Transduced normal and twitcher cells formed clusters when plated at high density. Transduction of twitcher oligodendrocytes plated at lower density, followed by differentiation, resulted in some cells having a completely normal appearance with highly branched processes. Other cells showed retraction and fragmentation. Perhaps over expression of GALC activity may be detrimental to oligodendrocytes. These studies demonstrate that the phenotype of twitcher oligodendrocytes can be corrected by providing GALC via gene transfer, and this could lead the way to future studies to treat this disease.

Constitutive expression of interleukin-1beta (IL-1beta) in rat oligodendrocytes

The RT-PCR analysis of RNA from progenitor and differentiated primary rat oligodendrocytes, and from the oligodendrocyte CG-4 cell line, shows the presence of the IL-1beta mRNA, the type I IL-1beta receptor and the IL-1 receptor accessory protein in these cells. In situ hybridization of a rat IL-1beta probe to primary progenitor and differentiated rat oligodendrocytes results in a positive signal. The double hybridization of the IL-1beta probe, together with an oligodendrocyte-specific differentiation marker, to sections of postnatal rat brain at different stages of differentiation is also positive. The double immuno-labelling technique utilized indicates coincidence of the signals on the brain slices. The results show that IL-1beta mRNA is constitutively expressed in rat brain oligodendrocytes from 1 day after birth onward. In agreement with this observation, CG-4 cells, primary progenitor and differentiated rat oligodendrocytes are positively stained by antibodies against IL-1beta. Postnatal brain slices from 1 and 4 day old and adult rats, labelled with a double immunofluorescence technique, are also stained by antibodies against IL-1beta. This signal coincides with that of antibodies against oligodendrocyte-specific surface markers. We conclude that IL-1beta is constitutively expressed in rat brain progenitor and differentiated oligodendrocytes.

Human FIGF: cloning, gene structure, and mapping to chromosome Xp22.1 between the PIGA and the GRPR genes

We report the identification, structural characterization, and mapping of the human FIGF gene. FIGF is the human homologue of mouse figf (c-fos-induced growth factor), a new member of the platelet-derived growth factor/vascular endothelial growth factor (PDGF/VEGF) family. It codes for a secreted factor with mitogenic and morphogenic activity on fibroblast cells. The predicted amino acid sequence of FIGF is 84% identical to that of the mouse protein, and it is highly conserved (up to 40%) in the dimerization domain with respect to the VEGF members of the family. The 2.5-kb mRNA of FIGF was detected in adult lung and heart tissues. The gene spans about 50 kb and is organized into seven exons and six introns. The FIGF promoter contains an optimal AP-1-binding site and lacks a canonical TATA box. Fluorescence in situ hybridization mapped FIGF to chromosomal region Xp22.1. The subsequent identification of YAC positive clones from this region allowed us to refine the map and localize FIGF centromeric to the phosphatidylinositol glycan complementation class A (PIGA) gene and telomeric to the gastrin-releasing peptide receptor (GRPR) gene. FIGF and PIGA genes lie next to each other in a head-to-tail orientation, with the FIGF polyadenylation signal about 12 kb from the PIGA transcriptional start site.