R-spondin1 and FOXL2 act into two distinct cellular types during goat ovarian differentiation

<p>Abstract</p> <p>Background</p> <p>Up to now, two loci have been involved in XX sex-reversal in mammals following loss-of-function mutations, PIS (Polled Intersex Syndrome) in goats and <it>R-spondin1 </it>(<it>RSPO1</it>) in humans. Here, we analyze the possible interaction between these two factors during goat gonad development. Furthermore, since functional redundancy between different <it>R-spondins </it>may influence gonad development, we also studied the expression patterns of <it>RSPO2, 3 </it>and <it>4</it>.</p> <p>Results</p> <p>Similarly to the mouse, <it>RSPO1 </it>shows a sex-dimorphic expression pattern during goat gonad development with higher levels in the ovaries. Interestingly, the PIS mutation does not seem to influence its level of expression. Moreover, using an RSPO1 specific antibody, the RSPO1 protein was localized in the cortical area of early differentiating ovaries (36 and 40 d<it>pc</it>). This cortical area contains the majority of germ cell that are surrounded by FOXL2 negative somatic cells. At latter stages (50 and 60 d<it>pc</it>) RSPO1 protein remains specifically localized on the germ cell membranes. Interestingly, a time-specific relocation of RSPO1 on the germ cell membrane was noticed, moving from a uniform distribution at 40 d<it>pc </it>to a punctuated staining before and during meiosis (50 and 60 d<it>pc </it>respectively). Interestingly, also <it>RSPO2 </it>and <it>RSPO4 </it>show a sex-dimorphic expression pattern with higher levels in the ovaries. Although <it>RSPO4 </it>was found to be faintly and belatedly expressed, the expression of <it>RSPO2 </it>increases at the crucial 36 d<it>pc </it>stage, as does that of <it>FOXL2</it>. Importantly, <it>RSPO2 </it>expression appears dramatically decreased in XX PIS^-/-gonads at all three tested stages (36, 40 and 50 d<it>pc</it>).</p> <p>Conclusion</p> <p>During goat ovarian development, the pattern of expression of <it>RSPO1 </it>is in agreement with its possible anti-testis function but is not influenced by the PIS mutation. Moreover, our data suggest that RSPO1 may be associated with germ cell development and meiosis. Interestingly, another RSPO gene, RSPO2 shows a sex-dimorphic pattern of expression that is dramatically influenced by the PIS mutation.</p

Dietary Cholesterol-Induced Post-Testicular Infertility

This work shows that an overload of dietary cholesterol causes complete infertility in dyslipidemic male mice (the Liver X Receptor-deficient mouse model). Infertility resulted from post-testicular defects affecting the fertilizing potential of spermatozoa. Spermatozoa of cholesterol-fed lxr−/− animals were found to be dramatically less viable and motile, and highly susceptible to undergo a premature acrosome reaction. We also provide evidence, that this lipid-induced infertility is associated with the accelerated appearance of a highly regionalized epididymal phenotype in segments 1 and 2 of the caput epididymidis that was otherwise only observed in aged LXR-deficient males. The epididymal epithelial phenotype is characterized by peritubular accumulation of cholesteryl ester lipid droplets in smooth muscle cells lining the epididymal duct, leading to their transdifferentiation into foam cells that eventually migrate through the duct wall, a situation that resembles the inflammatory atherosclerotic process. These findings establish the high level of susceptibility of epididymal sperm maturation to dietary cholesterol overload and could partly explain reproductive failures encountered by young dyslipidemic men as well as ageing males wishing to reproduce

SLY regulates genes involved in chromatin remodeling and interacts with TBL1XR1 during sperm differentiation

Sperm differentiation requires unique transcriptional regulation and chromatin remodeling after meiosis to ensure proper compaction and protection of the paternal genome. Abnormal sperm chromatin remodeling can induce sperm DNA damage, embryo lethality and male infertility, yet, little is known about the factors which regulate this process. Deficiency in Sly, a mouse Y chromosome-encoded gene expressed only in postmeiotic male germ cells, has been shown to result in the deregulation of hundreds of sex chromosome-encoded genes associated with multiple sperm differentiation defects and subsequent male infertility. The underlying mechanism remained, to date, unknown. Here, we show that SLY binds to the promoter of sex chromosome-encoded and autosomal genes highly expressed postmeiotically and involved in chromatin regulation. Specifically, we demonstrate that Sly knockdown directly induces the deregulation of sex chromosome-encoded H2A variants and of the H3K79 methyltransferase DOT1L. The modifications prompted by loss of Sly alter the postmeiotic chromatin structure and ultimately result in abnormal sperm chromatin remodeling with negative consequences on the sperm genome integrity. Altogether our results show that SLY is a regulator of sperm chromatin remodeling. Finally we identified that SMRT/N-CoR repressor complex is involved in gene regulation during sperm differentiation since members of this complex, in particular TBL1XR1, interact with SLY in postmeiotic male germ cells.This work was supported by Inserm (Institut National de la Sante et de la Recherche Medicale), the Agence Nationale de la Recherche program ANR-12–JSV2-0005–01 (to JC), Labex ‘Who am I?’(ANR-11- LABX-0071 under program ANR-11-IDEX-0005-01) and a Marie Curie fellowship FP7-PEOPLE-2010-IEF-273143 (to JC

Epididymis Response Partly Compensates for Spermatozoa Oxidative Defects in snGPx4 and GPx5 Double Mutant Mice

We report here that spermatozoa of mice lacking both the sperm nucleaus glutathione peroxidase 4 (snGPx4) and the epididymal glutathione peroxidase 5 (GPx5) activities display sperm nucleus structural abnormalities including delayed and defective nuclear compaction, nuclear instability and DNA damage. We show that to counteract the GPx activity losses, the epididymis of the double KO animals mounted an antioxydant response resulting in a strong increase in the global H2O2-scavenger activity especially in the cauda epididymis. Quantitative RT-PCR data show that together with the up-regulation of epididymal scavengers (of the thioredoxin/peroxiredoxin system as well as glutathione-S-transferases) the epididymis of double mutant animals increased the expression of several disulfide isomerases in an attempt to recover normal disulfide-bridging activity. Despite these compensatory mechanisms cauda-stored spermatozoa of double mutant animals show high levels of DNA oxidation, increased fragmentation and greater susceptibility to nuclear decondensation. Nevertheless, the enzymatic epididymal salvage response is sufficient to maintain full fertility of double KO males whatever their age, crossed with young WT female mice

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Etudes fonctionnelles de protéines clés du développement gonadique chez la chèvre

Chez les mammifères, la gonade embryonnaire a la potentialité de se différencier en deux organes morphologiquement et physiologiquement différents : un testicule ou un ovaire. L orientation de la différenciation gonadique vers l un ou l autre des deux sexes va dépendre de la présence ou non d un gène porté par le chromosome Y : le gène SRY. En sa présence, la différenciation testiculaire va avoir lieu, à l inverse en son absence la différenciation ovarienne sera privilégiée. De nombreuses études visent encore à élucider les voies moléculaires impliquées dans cette différenciation gonadique. C est dans cette optique que j ai œuvré au cours de ma thèse et ceci en utilisant le modèle caprin. Ainsi, nos études sur le gène PrnD semblent indiquer que la protéine Doppel peut être impliquée dans la différenciation gonadique. Par ailleurs, nos travaux sur les gènes R-spondin ont permis d apporter de nouvelles données moléculaires sur la fonction de deux gènes clés de la différenciation ovarienne, RSPO1 et FOXL2. Nos résultats démontrent pour la première fois qu un ovaire présente très précocement au moins deux types de cellules somatiques ; celles exprimant RSPO1 qui sont en étroites relations avec les cellules germinales, et celles exprimant FOXL2 qui sont directement impliquées dans la stéroidogenèse ovarienne fœtale. Outre ces résultats, nos travaux ouvrent différentes perspectives d études concernant entre autre, le rôle de RSPO1 sur les cellules germinales, le lien entre FOXL2 et un de ses nouveaux gènes cibles potentiels, RSPO2.In mammals, the embryonic gonad can give either a testis or an ovary. The choice of gonad differentiation depends of the presence or not of a gene bearing by the Y chromosome: SRY. In its presence, the gonad differentiates into a testis and in its absence the ovary differentiation take place. A large number of studies are carried out in order to elucidate the molecular pathway involved in this gonad differentiation. This is also the goal of my thesis using the goat model. Our studies on the PrnD gene seem to show that Doppel protein may be involved in the gonad differentiation. Furthermore, our studies on the R-spondin gene brought new molecular data on the role of both important genes of the ovary differentiation: RSPO1 and FOXL2. For the first time, our results show that an ovary contains two types of somatic cells; those expressing RSPO1 which were in short relation with the germ cells and those expressing FOXL2 which were directly involved in the fetal ovarian steroidogenesis. Our results open different perspectives concerning the RSPO1 role on the germ cells, the link between FOXL2 and one of its putative target gene, RSPO2.VERSAILLES-BU Sciences et IUT (786462101) / SudocSudocFranceF

Recent knowledge concerning mammalian sperm chromatin organization and its potential weaknesses when facing oxidative challenge

International audienc

Protection post-testiculaire des gamètes mâles contre les dommages radicalaires

Lorsqu’ils quittent le testicule, les spermatozoïdes sont fonctionnellement immatures et disposent de moyens de défense intrinsèques limités. Ils deviendront mobiles et fécondants après leur descente et leur maturation progressive dans le tubule épididymaire. L’épididyme assure aussi la survie et la protection des gamètes mâles pendant cette phase de maturation post-testiculaire et pendant la période de stockage entre deux éjaculations. Parmi les agressions communes auxquelles les spermatozoïdes sont soumis, le stress oxydant occupe une place particulière et ambiguë. Les événements de la maturation épididymaire requièrent un certain niveau d’oxydation alors que le gamète mâle y est, par ailleurs, particulièrement sensible. Un équilibre très fin entre oxydation ménagée bénéfique et stress oxydant délétère est ainsi maintenu dans l’environnement épididymaire. Les enzymes antioxydantes de la famille des peroxydases à glutathion à activité thiol peroxydase jouent un rôle clé dans le contrôle de cet équilibre

Investigation of antioxidant systems in human meibomian gland and conjunctival tissues

International audienc