Vaspin, a novel adipokine in woman granulosa cells physiology and PCOS pathogenesis?

Vaspin is a novel adipokine mainly expressed in visceral adipose tissue and closely related to obesity and insulin-resistance. Currently, data about its ovarian expression are limited to animal models and its role in human reproduction is largely unexplored. Our study's aims were then to characterise vaspin expression in the human ovary and to study in vitro its effects on granulosa cells physiology. Secondly, we assessed vaspin and its receptor GRP78 variations in granulosa cells and follicular fluid of a cohort of 112 infertile women undergoing an in vitro fertilisation procedure and allocated to three groups, each including normal-weight and obese subjects: 34 PCOS patients, 33 women with isolated polycystic ovary morphology (ECHO group) and 45 controls. Vaspin and GRP78 expression in the ovary was assessed by immunohistochemistry, RT-qPCR and Western blot. Granulosa cells and follicular fluid were analysed by RT-qPCR and ELISA, respectively. In vitro, granulosa cells metabolism was studied after stimulation with recombinant human vaspin, with and without a siRNA directed against GRP78. Vaspin was highly expressed in the human ovary and concentration-dependently enhanced granulosa cells steroidogenesis, proliferation and viability through GRP78 (P < 0.0001). Vaspin levels in both granulosa cells and follicular fluid were significantly higher in obese women (P < 0.0001) and in the normal-weight ECHO group (P < 0.001), which also had the highest expression rates of GRP78 (P < 0.05). Although further investigation is needed, vaspin appears as a novel modulator of human granulosa cells physiology and possibly plays a role in PCOS pathogenesis, notably protecting from insulin-resistance induced complications.

Human eggs, zygotes, and embryos express the receptor angiotensin 1-converting enzyme 2 and transmembrane serine protease 2 protein necessary for severe acute respiratory syndrome coronavirus 2 infection.

OBJECTIVE: To study messenger ribonucleic acid (mRNA) and protein expressions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry receptors (angiotensin 1-converting enzyme 2 [ACE2] and CD147) and proteases (transmembrane serine protease 2 [TMPRSS2] and cathepsin L [CTSL]) in human oocytes, embryos, and cumulus (CCs) and granulosa cells (GCs). DESIGN: Research study. SETTING: Clinical in vitro fertilization (IVF) treatment center. PATIENTS: Patients undergoing IVF were treated at the Colorado Center for Reproductive Medicine. INTERVENTIONS: Oocytes (germinal vesicle and metaphase II [MII]) and embryos (1-cell [1C] and blastocyst [BL]) were donated for research at the disposition by the patients undergoing IVF. Follicular cells (CC and GC) were collected from women undergoing egg retrieval after ovarian stimulation without an ovulatory trigger for in vitro maturation/IVF treatment cycles. MAIN OUTCOME MEASURES: Presence or absence of ACE2, CD147, TMPRSS2, and CTSL mRNAs detected using quantitative reverse transcription polymerase chain reaction and proteins detected using capillary Western blotting in human oocytes, embryos, and ovarian follicular cells. RESULTS: The quantitative reverse transcription polymerase chain reaction analysis revealed high abundance of ACE2 gene transcripts in germinal vesicle and MII oocytes than in CC, GC, and BL. ACE2 protein was present only in the MII oocytes, and 1C and BL embryos, but other ACE2 protein variants were observed in all the samples. TMPRSS2 protein was present in all the samples, whereas mRNA was observed only in the BL stage. All the samples were positive for CD147 and CTSL mRNA expressions. However, CCs and GCs were the only samples that showed coexpression of both CD147 and CTSL proteins in low abundance. CONCLUSIONS: CCs and GCs are the least susceptible to SARS-CoV-2 infection because of lack of the required combination of receptors and proteases (ACE2/TMPRSS2 or CD147/CTSL) in high abundance. The coexpression of ACE2 and TMPRSS2 proteins in the MII oocytes, zygotes, and BLs demonstrated that these gametes and embryos have the cellular machinery required and, thus, are potentially susceptible to SARS-CoV-2 infection if exposed to the virus. However, we do not know whether the infection occurs in vivo or in vitro in an assisted reproductive technology setting yet.

Female reproductive tract has low concentration of SARS-CoV2 receptors.

There has been significant concern regarding fertility and reproductive outcomes during the SARS-CoV2 pandemic. Recent data suggests a high concentration of SARS-Cov2 receptors, ACE2 or TMPRSS2, in nasal epithelium and cornea, which explains person-to-person transmission. We investigated the prevalence of SARS-CoV2 receptors among reproductive tissues by exploring the single-cell sequencing datasets from uterus, myometrium, ovary, fallopian tube, and breast epithelium. We did not detect significant expression of either ACE2 or TMPRSS2 in the normal human myometrium, uterus, ovaries, fallopian tube, or breast. Furthermore, none of the cell types in the female reproductive organs we investigated, showed the co-expression of ACE2 with proteases, TMPRSS2, Cathepsin B (CTSB), and Cathepsin L (CTSL) known to facilitate the entry of SARS2-CoV2 into the host cell. These results suggest that myometrium, uterus, ovaries, fallopian tube, and breast are unlikely to be susceptible to infection by SARS-CoV2.

A review of severe acute respiratory syndrome coronavirus 2 infection in the reproductive system.

An outbreak of pneumonia associated with coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred in Wuhan, China, in December 2019, and has been spread worldwide rapidly now. Over 5.3-million confirmed cases and 340,000 disease-associated deaths have been found till May 25, 2020. The potential pathophysiology for SARS-CoV-2 to affect the target is via the receptor, angiotensin-converting enzyme 2 (ACE2). ACE2 can be found in the respiratory, cardiovascular, gastrointestinal tract, urinary tract, and reproductive organs such as human ovaries and Leydig cells in the testis. This receptor plays a dominant role in the fertility function. Considering the crucial roles of testicular cells of the male reproductive system, increasing numbers of studies focus on the effects of SARS-CoV-2 on the testis. In this literature, we reviewed several studies to evaluate the relevance between SARS-CoV-2, ACE receptor, and female and male reproductive system and found that the risk of being attacked by SARS-CoV-2 is higher in males than in females. Since men infected with SARS-CoV-2 virus may have the risk of impaired reproductive performance, such as the orchitis and an elevated of luteinizing hormone (LH), and additionally, SARS-CoV-2 virus may be found in semen, although the latter is still debated, all suggest that we should pay much attention to sexual transmitted disease and male fertility after recovering from COVID-19.

A comprehensive investigation of the mRNA and protein level of ACE2, the putative receptor of SARS-CoV-2, in human tissues and blood cells.

The outbreak of pneumonia caused by SARS-CoV-2 posed a great threat to global human health, which urgently requires us to understand comprehensively the mechanism of SARS-CoV-2 infection. Angiotensin-converting enzyme 2 (ACE2) was identified as a functional receptor for SARS-CoV-2, distribution of which may indicate the risk of different human organs vulnerable to SARS-CoV-2 infection. Previous studies investigating the distribution of ACE2 mRNA in human tissues only involved a limited size of the samples and a lack of determination for ACE2 protein. Given the heterogeneity among humans, the datasets covering more tissues with a larger size of samples should be analyzed. Indeed, ACE2 is a membrane and secreted protein, while the expression of ACE2 in blood and common blood cells remains unknown. Herein, the proteomic data in HIPED and the antibody-based immunochemistry result in HPA were collected to analyze the distribution of ACE2 protein in human tissues. The bulk RNA-seq profiles from three separate public datasets including HPA tissue Atlas, GTEx, and FANTOM5 CAGE were also obtained to determine the expression of ACE2 in human tissues. Moreover, the abundance of ACE2 in human blood and blood cells was determined by analyzing the data in the PeptideAtlas and the HPA Blood Atlas. We found that the mRNA expression cannot reflect the abundance of ACE2 factor due to the strong differences between mRNA and protein quantities of ACE2 within and across tissues. Our results suggested that ACE2 protein is mainly expressed in the small intestine, kidney, gallbladder, and testis, while the abundance of which in brain-associated tissues and blood common cells is low. HIPED revealed enrichment of ACE2 protein in the placenta and ovary despite a low mRNA level. Further, human secretome shows that the average concentration of ACE2 protein in the plasma of males is higher than those in females. Our research will be beneficial for understanding the transmission routes and sex-based differences in susceptibility of SARS-CoV-2 infection.

Prior and novel coronaviruses, Coronavirus Disease 2019 (COVID-19), and human reproduction: what is known?

OBJECTIVE: To summarize current understanding of the effects of novel and prior coronaviruses on human reproduction, specifically male and female gametes, and in pregnancy. DESIGN: Review of English publications in PubMed and Embase to April 6, 2020. METHOD(S): Articles were screened for reports including coronavirus, reproduction, pathophysiology, and pregnancy. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Reproductive outcomes, effects on gametes, pregnancy outcomes, and neonatal complications. RESULT(S): Seventy-nine reports formed the basis of the review. Coronavirus binding to cells involves the S1 domain of the spike protein to receptors present in reproductive tissues, including angiotensin-converting enzyme-2 (ACE2), CD26, Ezrin, and cyclophilins. Severe Acute Respiratory Syndrome Coronavirus 1 (SARS-CoV-1) may cause severe orchitis leading to germ cell destruction in males. Reports indicate decreased sperm concentration and motility for 72-90 days following Coronavirus Disease 2019 (COVID-19) infection. Gonadotropin-dependent expression of ACE2 was found in human ovaries, but it is unclear whether SARS-Coronavirus 2 (CoV-2) adversely affects female gametogenesis. Evidence suggests that COVID-19 infection has a lower maternal case fatality rate than SARS or Middle East respiratory syndrome (MERS), but anecdotal reports suggest that infected, asymptomatic women may develop respiratory symptoms postpartum. Coronavirus Disease 2019 infections in pregnancy are associated with preterm delivery. Postpartum neonatal transmission from mother to child has been reported. CONCLUSION(S): Coronavirus Disease 2019 infection may affect adversely some pregnant women and their offspring. Additional studies are needed to assess effects of SARS-CoV-2 infection on male and female fertility.