Time-resolved Fluorescence and Generalized Polarization: Innovative tools to assess bull sperm membrane dynamics during slow freezing.

During slow freezing, spermatozoa undergo membrane alterations that compromise their ability of fertilizing. These alterations are cause either by cold shock or by the use of cryoprotectants known to be cytotoxic. However, little is known about the membrane changes that occurred during freezing. Here, we combined Generalized Polarization (GP), Time-resolved Fluorescence and laurdan fluorescence properties to investigate the changes in membrane fluidity and dynamics during slow freezing of bull sperm. We successfully demonstrated that laurdan may be distributed in three different local environments that correspond to different membrane lipid composition. These environments wont behave the same way when the cells will be subjected to either a chemical treatment (adding the cryoprotectants) or a physical treatment (freezing).

Apolipoprotein B is regulated by gonadotropins and constitutes a predictive biomarker of IVF outcomes.

BACKGROUND: Follicular fluid (FF) is an important micro-environment influencing oocyte growth, its development competence, and embryo viability. The FF content analysis allows to identify new relevant biomarkers, which could be predictive of in vitro fertilization (IVF) outcomes. Inside ovarian follicle, the amount of FF components from granulosa cells (GC) secretion, could be regulated by gonadotropins, which play a major role in follicle development. METHODS: This prospective study included 61 female undergoing IVF or Intra-cytoplasmic sperm injection (ICSI) procedure. Apolipoprotein B (APOB) concentrations in follicular fluid and APOB gene and protein expression in granulosa cells from reproductively aged women undergoing an in vitro fertilization program were measured. The statistical analyses were performed according to a quartile model based on the amount of APOB level found in FF. RESULTS: Amounts of APOB were detected in human FF samples (mean ± SD: 244.6 ± 185.9 ng/ml). The odds of obtaining an oocyte in the follicle and a fertilized oocyte increased significantly when APOB level in FF was higher than 112 ng/ml [i.e., including in Quartile Q 2, Q3 and Q4] (p = 0.001; p < 0.001, respectively). The probabilities of obtaining an embryo and a top quality embryo on day 2, were significantly higher if APOB levels were within the ranges of 112 and 330 ng/ml (i.e. in Q2 and Q3) or 112 and 230 ng/ml (i.e. in Q2), respectively (p < 0.001; p = 0.047, respectively). In addition, our experiments in vitro indicated that APOB gene and protein expression, along with APOB content into culture were significantly under-expressed in GC upon stimulation with gonadotropins (follicular stimulating hormone: FSH and/or human chorionic gonadotropin: hCG). CONCLUSION: We are reporting a positive and statistically significant associations between APOB and oocyte retrieval, oocyte fertilization, and embryo quality. Using an experimental study component, the authors report significant reduced APOB expression and content for luteinized granulosa cells cultured in the presence of gonadotropins.

Number of Intermediate Follicles. An Independent Risk Factor of Multiple Pregnancies in Intrauterine Insemination Cycles with Recombinant Follicle-Stimulating Hormone.

OBJECTIVE: To identify risk factors for multiple pregnancies in intrauterine insemination (IUI) cycles with recombinant follicle-stimulating hormone (r-FSH). STUDY DESIGN: A retrospective study including 205 IUI cycles with r-FSH which led to clinical pregnancies was conducted. A total of 145, singleton pregnancies and 60 multiple pregnancies were compared according to clinical characteristics and parameters of ovarian stimulation and IUI procedure. The relationships between size and number of follicles and serum estradiol (E2) levels and the risk of multiple pregnancies were investigated using multiple logistic regression analyses. RESULTS: The means of infertility length, serum E2 levels, the number of follicles 10 mm, 12 mm, and ≥ 16 mm, and the number of intermediate follicles (from 12 to ≤ 15 mm) at the day of ovulation triggering were significantly higher in the multiple pregnancy group as compared to in the singleton pregnancy group (p < 0.05). We first demonstrated that high E2 levels (≥ 1,000 pg/nL) and the number of intermediate follicles represent 2 independent and significant risk factors for multiple gestation in IUI cycles that used ovarian stimulation by r-FSH (p = 0.002 and p = 0.007, respectively). CONCLUSION: This study shows that high E2 levels and the number of intermediate follicles, independently of large follicles, can predict an increased risk of multiple pregnancy in r-FSH IUI cycles.

V-ATPase interacts with ARNO and Arf6 in early endosomes and regulates the protein degradative pathway.

The recruitment of the small GTPase Arf6 and ARNO from cytosol to endosomal membranes is driven by V-ATPase-dependent intra-endosomal acidification. The molecular mechanism that mediates this pH-sensitive recruitment and its role are unknown. Here, we demonstrate that Arf6 interacts with the c-subunit, and ARNO with the a2-isoform of V-ATPase. The a2-isoform is targeted to early endosomes, interacts with ARNO in an intra-endosomal acidification-dependent manner, and disruption of this interaction results in reversible inhibition of endocytosis. Inhibition of endosomal acidification abrogates protein trafficking between early and late endosomal compartments. These data demonstrate the crucial role of early endosomal acidification and V-ATPase/ARNO/Arf6 interactions in the regulation of the endocytic degradative pathway. They also indicate that V-ATPase could modulate membrane trafficking by recruiting and interacting with ARNO and Arf6; characteristics that are consistent with the role of V-ATPase as an essential component of the endosomal pH-sensing machinery.

HSP90 inhibitor NVP-BEP800 affects stability of SRC kinases and growth of T-cell and B-cell acute lymphoblastic leukemias.

T-cell and B-cell acute lymphoblastic leukemias (T-ALL, B-ALL) are aggressive hematological malignancies characterized by an accumulation of immature T- or B-cells. Although patient outcomes have improved, novel targeted therapies are needed to reduce the intensity of chemotherapy and improve the prognosis of high-risk patients. Using cell lines, primary cells and patient-derived xenograft (PDX) models, we demonstrate that ALL cells viability is sensitive to NVP-BEP800, an ATP-competitive inhibitor of Heat shock protein 90 (HSP90). Furthermore, we reveal that lymphocyte-specific SRC family kinases (SFK) are important clients of the HSP90 chaperone in ALL. When PDX mice are treated with NVP-BEP800, we found that there is a decrease in ALL progression. Together, these results demonstrate that the chaperoning of SFK by HSP90 is involved in the growth of ALL. These novel findings provide an alternative approach to target SRC kinases and could be used for the development of new treatment strategies for ALL.

Analysis of multivariate images in fluorescence microscopy.

A multivariate image is an image stack in which each pixel contains several variables. Such images are common in many fields (medicine, imaging microscopy, satellite imaging...) and their analysis requires adapted multivariate statistical methods. In fluorescence imaging microscopy, different probes or different measurements such as intensity, fluorescence lifetime or spectral information can be observed from one view. However, this is not yet analysed as multivariate images. Here, we are presenting a full approach of multivariate analysis of fluorescence microscopy images and we are proposing a free R package (multifluo) to conduct it.

Impact on ICSI outcomes of adding 24 h of in vitro culture before testicular sperm freezing: a retrospective study.

PURPOSE: To compare sperm parameters and intracytoplasmic sperm injection (ICSI) outcomes for testicular spermatozoa frozen on the day of the biopsy (DO) with those frozen after 24 h of in vitro culture (D1). METHODS: In this retrospective study, from 1999 to 2012, forty-nine azoospermic patients were included to compare sperm (motility and viability) and outcomes (fertilization (FR), implantation (IR), pregnancy (PR) and delivery rates (DR)). RESULTS: The in vitro culture increased total motility (+2.8 %, p = 0.0161) but decreased viability (-8.3 %, p = 0.007). After 24 h of culture, the post-thaw changes in motility and viability were not significant. Twenty-six couples underwent ICSI: thirty-four ICSI were performed with spermatozoa cryopreserved at D0 and eighteen with spermatozoa frozen at D1. Cumulated IR and DR were lower for ICSI with D1 spermatozoa than with D0 spermatozoa (IR: 21.6 % with D0 vs. 9.8 % with D1, p = 0.102; DR: 27.5 % with D0 vs. 8.3 % with D1, p = 0.049). CONCLUSION: Despite improving motility, freezing spermatozoa 24 h after testicular biopsy had a potential negative effect on ICSI outcomes, notably on delivery rates. These results may be related to the detrimental impact of the additional culture on the nuclear integrity of sperm.

OBJECTIF: Comparer les paramètres spermatiques et les issues de fécondation in vitro avec micro-injection (ICSI) de spermatozoïdes testiculaires congelés le jour de la biopsie (D0) avec ceux congelés après 24 heures de culture in vitro (D1). MÉTHODES: Dans cette étude rétrospective, de 1999 à 2012, quarante-neuf patients présentant une azoospermie ont été inclus pour comparer les paramètres spermatiques (mobilité et vitalité) et les issues d'ICSI (taux de fécondation (FR), d'implantation (IR), de grossesse (PR), et d'accouchement (DR)). RÉSULTATS: La culture in vitro augmentait la mobilité (+2.8 %, p = 0.0161) mais diminuait la vitalité (-8.3 %, p = 0.007). Après cumul des 24 heures de culture et congélation, les différences observées n'étaient plus significatives. Vingt-six couples ont eu au moins une ICSI : 34 ont été réalisées avec des spermatozoïdes congelés à D0 et 18 ont été réalisées avec des spermatozoïdes congelés à D1. Les taux d'implantation et d'accouchement cumulés étaient plus faibles avec les spermatozoïdes congelés à D1 par rapport à ceux congelés à D0 (IR: 21.6 % avec D0 vs. 9.8 % avec D1, p = 0.102; DR: 27.5 % avec D0 vs. 8.3 % avec D1, p = 0.049). CONCLUSION: Malgré l'augmentation de la mobilité, la congélation de spermatozoïdes testiculaires 24 heures après la biopsie apparait avoir un impact négatif sur les issues d'ICSI, notamment sur les taux d'accouchement. Ces résultats pourraient être en lien avec les effets néfastes de l'association des deux procédés (l'incubation pendant 24H cumulée à la congélation-décongélation) sur l'intégrité nucléaire spermatique.

Outcomes with intracytoplasmic sperm injection of cryopreserved sperm from men with spinal cord injury.

BACKGROUND: Erectile dysfunction, ejaculatory dysfunction and poor semen quality are the main causes of infertility in men with spinal cord injury (SCI). Different sperm retrieval techniques such as penile vibratory stimulation (PVS), electro-ejaculation (EEJ) or surgical sperm retrieval (SSR) associated or not with sperm cryopreservation can be offered to these patients to preserve their fertility. If fatherhood cannot be achieved naturally, assisted reproductive techniques can be offered to these patients using either fresh or frozen/thawed sperm. The aim of the study was to report in SCI patients from Dijon (Burgundy) and in the literature, intracytoplasmic sperm injection (ICSI) outcomes using frozen sperm obtained either by antegrade ejaculation (PVS or sexual intercourse) or by SSR. METHODS: A retrospective analysis was performed in Dijon, Burgundy over a 17 year period (1995-2011) on a cohort of 19 SCI men (6 quadriplegics and 13 paraplegics, mean age: 25.2 ± 5.6 years) who underwent a sperm cryopreservation followed or not by intracytoplasmic sperm injection (ICSI). Patients were divided into two groups according to the sperm retrieval method used (antegrade ejaculation group (n=10): penile vibratory stimulation (PVS) for 9 patients and sexual intercourse for 1 patient and surgical sperm retrieval (SSR) group: n=9). The sperm parameters in both groups were analyzed. Pregnancy outcomes in the 8 couples who underwent ICSI were evaluated. RESULTS: The fertilization rates were 57 and 55%, the embryo's cleavage rates were 90 and 93% in the antegrade ejaculation and SSR groups respectively. Among the 8 couples who underwent ICSI, 5 couples achieved pregnancy. The pregnancy rates per couple were 50% and 75% in the antegrade and SSR groups respectively. CONCLUSIONS: Although some studies don't recommend freezing sperm in SCI patients, the pregnancy rates presented in this study are encouraging and warrant the use of frozen/thawed sperm in very specific situations.

INTRODUCTION: L'infertilité chez l'homme blessé médullaire s'explique d'une part par une dysfonction érectile et éjaculatoire et d'autre part par l'altération de la qualité des paramètres spermatiques. Différentes techniques facilitant le recueil de sperme (vibromassage, électro-éjaculation et prélèvement chirurgical de spermatozoïdes) peuvent être proposées à ces patients. Le recueil de sperme peut s'accompagner ou non d'une autoconservation. Si une grossesse n'est pas obtenue naturellement alors des techniques d'assistance médicale à la procréation peuvent être envisagées (insémination, fécondation in vitro avec ou sans micro-injection). Le but de ce travail a consisté à évaluer les issues de grossesses dans la littérature et sur une cohorte de patients de Dijon, blessés médullaires ayant eu recours à de la fécondation in vitro avec micro-injection (ICSI) à partir de spermatozoïdes cryoconservés éjaculés ou chirurgicaux. MÉTHODES: Il s'agit d'une étude rétrospective réalisée sur la base de registres des patients pris en charge au CECOS (centre d'étude de la conservation des œufs et du sperme) de Dijon entre 1995 et 2011 (6 patients tétraplégiques, 13 patients paraplégiques, moyenne d'âge : 25.2 ± 5.6 ans). Pour ces 19 patients, une autoconservation de sperme a été réalisée et 8 de ces patients ont eu recours à l'ICSI. Deux groupes de patients ont été définis, le groupe pour lequel les spermatozoïdes ont été obtenus par éjaculation antégrade (n=10 : 9 patients par vibromassage et 1 après rapports sexuels) et le groupe pour lequel les spermatozoïdes ont été obtenus chirurgicalement (n=9). Dans les deux groupes, les paramètres spermatiques ont été analysés ainsi que les issues de grossesses obtenues par ICSI réalisées avec des spermatozoïdes congelés. RÉSULTATS: Dans les groupes «éjaculation antégrade ¼ et « prélèvement chirurgical ¼, les taux moyens de fécondation par micro-injection étaient respectivement de 57% et 55% et les taux moyens de clivage embryonnaire de 90% et 93%. Parmi ces 8 couples, 5 ont obtenu une grossesse. Les taux de grossesse par couple étaient de 50% dans le groupe «éjaculation antégrade ¼ et de 75% dans le groupe « prélèvements chirurgicaux ¼. CONCLUSIONS: Bien que certaines équipes ne recommandent pas de réaliser une autoconservation de sperme chez les patients blessés médullaires, cette possibilité apparait selon les résultats présentés dans cette étude comme une option préventive satisfaisante.

Prostasomes as potential modulators of tyrosine phosphorylation in human spermatozoa.

Prostasomes, vesicles present in human semen, are known to play a role in male fertility. However, the mechanisms involved are still poorly understood. The present study looks at the direct influence of different concentrations of prostasomes on human sperm function in conditions supporting capacitation in vitro. Five million Percoll selected spermatozoa were incubated for 3 h at 37°C under an atmosphere of 5% CO2 in air, in 100 µl Biggers Whitten Whittingham's medium (BWW) containing polyvinyl alcohol (PVA, 1 mg/ml) and bovine serum albumin (BSA; 3 mg/ml) in the absence or presence of increasing concentrations of prostasomes (expressed in terms of their cholesterol content: 15; 30; 45 nmoles per 100 µL of incubation medium). After in vitro exposure of spermatozoa to prostasomes, our data indicate that i) tyrosine phosphorylation intensity of the 107 KDa protein band was dose dependently lower and ii) the percentage of viable and progressive motile spermatozoa was unchanged and the percentage of non-progressive motility decreased. In addition, the incubation of prostasomes with spermatozoa resulted in an enrichment of their lipid content. Our experiments suggest that adhesion of prostasomes to spermatozoa could be responsible for the decrease in Tyrosine phosphorylation and the alteration of the mean curvilinear velocity (VCL) and the average path velocity (VAP).

Alix (AIP1) is a vasopressin receptor (V2R)-interacting protein that increases lysosomal degradation of the V2R.

The vasopressin type 2 receptor (V2R) is a G protein-coupled receptor that plays a central role in renal water reabsorption. Termination of ligand (vasopressin) stimulation is an important physiological regulatory event, but few proteins that interact with the V2R during downregulation after vasopressin (VP) binding have been identified. Using yeast two-hybrid screening of a human kidney cDNA library, we show that a 100-kDa protein called ALG-2-interacting protein X (Alix) interacts with the last 29 amino acids of the V2R COOH terminus. This was confirmed by pull-down assays using a GST-V2R-COOH-tail fusion protein. Alix was immunolocalized in principal cells of the kidney, which also express the V2R. The function of the Alix-V2R interaction was studied by transfecting Alix into LLC-PK(1) epithelial cells expressing V2R-green fluorescent protein (GFP). Under basal conditions, V2R-GFP localized mainly at the plasma membrane. On VP treatment, V2R-GFP was internalized into perinuclear vesicles in the nontransfected cells. In contrast, V2R-GFP fluorescence was virtually undetectable 2 h after exposure to VP in cells that coexpressed Alix. Western blotting using an anti-GFP antibody showed marked degradation of the V2R after 2 h in the presence of VP and Alix, a time point at which little or no degradation was detected in the absence of Alix. In contrast, little or no degradation of the parathyroid hormone receptor was detectable in the presence or absence of Alix and/or the PTH ligand. The VP-induced disappearance of V2R-GFP was abolished by chloroquine, a lysosomal degradation inhibitor, but not by MG132, a proteosome inhibitor. These data suggest that Alix increases the rate of lysosomal degradation of V2R and may play an important regulatory role in the VP response by modulating V2R downregulation.

Defective thyroglobulin storage in LDL receptor-associated protein-deficient mice.

The molecular chaperone receptor-associated protein (RAP) is required for biosynthesis of megalin, an endocytic receptor for follicular thyroglobulin (Tg), the thyroid hormone precursor. RAP also binds to Tg itself, suggesting that it may affect Tg trafficking in various manners. To elucidate RAP function, we have studied the thyroid phenotype in RAP-knockout (RAP-KO) mice and found a reduction of Tg aggregates into thyroid follicles. Serum Tg levels were significantly increased compared with those of wild-type (WT) mice, suggesting a directional alteration of Tg secretion. In spite of these abnormalities, hormone secretion was maintained as indicated by normal serum thyroxine levels. Because Tg in thyroid extracts from RAP-KO mice contained thyroxine residues as in WT mice, we concluded that in RAP-KO mice, follicular Tg, although reduced, was nevertheless sufficient to provide normal hormone secretion. Serum TSH was increased in RAP-KO mice, and although no thyroid enlargement was observed, some histological features resembling early goiter were present. Megalin was decreased in RAP-KO mice, but this did not affect thyroid function, probably because of the concomitant reduction of follicular Tg. In conclusion, RAP is required for the establishment of Tg reservoirs, but its absence does not affect hormone secretion.

Influence of very low dietary intake of marine oil on some functional aspects of immune cells in healthy elderly people.

Ageing is a multifactorial process involving decreased antioxidant defences and immune functions. n-3 Polyunsaturated fatty acids have been associated with human health benefits, especially against inflammatory and autoimmune diseases. However, their immunomodulatory effects were usually observed with high dosages (>2 g/d) known to increase lipid peroxidation. In contrast, very low doses, that may prevent lipid peroxidation, might affect the immune system differently. To study the latter hypothesis further, we investigated whether the supplementation of healthy elderly people with very low doses of marine oil (MO), a docosahexaenoate (DHA)- and eicosapentaenoate (EPA)-rich triacylglycerol, was able to affect lymphocyte proliferation and biochemical markers known to be altered with age. In a randomized, double-blind design, twenty healthy elderly subjects were assigned to a placebo group (600 mg sunflower oil/d) or to a group consuming 600 mg MO/d providing 150 mg DHA + 30 mg (EPA) for 6 weeks. At day 42, the proliferative responses of lymphocytes to several mitogens were significantly (P<0.01) decreased in the MO group compared with control values. This was accompanied by a slight lowering of their cytosolic cyclic nucleotide phosphodiesterase (PDE) activity, a marked and significant (P<0.05) increase of their particulate PDE activity (+56-57 %) and a slight but significant (P<0.05) increase in cyclic nucleotide intracellular levels. At the same time, the glutathione peroxidase activity was markedly and significantly (P<0.01) depressed in the MO group. None of these modifications could be seen in the placebo group. Collectively, these results demonstrate that even very low doses of n-3 fatty acids are sufficient to affect the immune responses of elderly subjects.