Impairment of human immunodeficiency virus type-1 integrase SUMOylation correlates with an early replication defect

HIV-1 integrase (IN) orchestrates the integration of the reverse transcribed viral cDNA into the host cell genome and participates also in other steps of HIV-1 replication. Cellular and viral factors assist IN in performing its multiple functions, and post-translational modifications contribute to modulate its activities. Here, we show that HIV-1 IN is modified by SUMO proteins and that phylogenetically conserved SUMOylation consensus motifs represent major SUMO acceptor sites. Viruses harboring SUMOylation site IN mutants displayed a replication defect that was mapped during the early stages of infection, before integration but after reverse transcription. Because SUMOylation-defective IN mutants retained WT catalytic activity, we hypothesize that SUMOylation might regulate the affinity of IN for co-factors, contributing to efficient HIV-1 replication.

Orthotopic and heterotopic ovarian tissue transplantation

BACKGROUND

Transplantation of ovarian tissue is, at present, the only clinical option available to restore fertility using cryopreserved ovarian tissue. More than 30 transplantations of cryopreserved tissue have been reported, and six babies have been born, worldwide, following this procedure. Despite these encouraging results, it is essential to optimize the procedure by improving the follicular survival, confirming safety and developing alternatives. Here, we review the different factors affecting follicular survival and growth after grafting.

METHODS

Relevant studies were identified by searching Pubmed up to January 2009 with English language limitation. The following key words were used: (ovarian tissue or whole ovary) AND (transplantation) AND (cryopreservation or pregnancy). Using the literature and personal experience, we examined relevant data on the different exogenous and clinical factors affecting follicular development after grafting.

RESULTS

Clinical factors such as the patient's age and the transplantation sites influenced the lifespan of the graft. A heterotopic transplantation site is not optimal but offers some advantages and it may also promote the hormonal environment after a combined heterotopic and orthotopic transplantation. Exogenous factors such as antioxidants, growth factors or hormones were tested to improve follicular survival; however, their efficiency regarding further follicular development and fertility potential remains to be established.

CONCLUSION

Additional evidence is required to define optimal conditions for ovarian tissue transplantation. Alternatives such as whole ovary or isolated follicles transplantations require further investigation but are likely to be successful in humans in the future.

Preimplantation genetic diagnosis in an HIV-serodiscordant couple carrier for sickle cell disease: lessons from a case report

Since 1999, the Erasme Hospital Fertility Clinic has carried a special programme for patients with HIV seropositivity. The philosophy of the programme is to give access to these patients in a secure environment to the same technological facilities available to any other patients. Many of these patients being native from sub-Saharan countries, they are often sickle cell disease (SCD) carriers, a common autosomal recessive disorder in these regions, and a severe affection in homozygotes. We hereby report, for the first time, the birth of a healthy sickle haemoglobin (HbS) heterozygous baby after preimplantation genetic diagnosis (PGD) for SCD in an HIV-serodiscordant couple of HbS mutation carriers with longstanding infertility. The prospective mother was 35 years old and HIV positive with an undetectable viral load under highly active antiretroviral therapy. One carrier embryo was transferred and resulted in the birth of a healthy HbS carrier baby girl. Despite stimulation difficulties, sometimes described in HIV patients, PGD represents an interesting additional technology, especially in populations where the coexistence of both diseases is frequent. PGD could even be preferred to prenatal diagnosis for couples of HbS carriers if the woman is HIV positive, as invasive prenatal samplings carry a risk of materno-foetal viral transmission.

[Preimplantation genetic diagnosis (PGD): the Erasme Hospital experience]

The clinical activity of the preimplantation genetic diagnosis (PGD) at Erasme Hospital was carried out since September 1999 for a 47,XYY patient. Up to 31 December 2007, 79 PGD cycles were carried out (45 couples) for either chromosomal structural abnormalities (robertsonian and reciprocal translocations, pericentric inversion, deletion) (n = 41), chromosomal numerical abnormalities (47,XXY, 47,XYY, 45,X/46,XX) (n = 10), aneuploidy screening for recurrent miscarriages or multiple in vitro fertilization failures (n = 10), autosomal recessive diseases (cystic fibrosis and sickle cell anaemia) (n = 12) or X-linked disorders (n = 6). A total of 475 embryos were biopsied for genetic analysis. Unaffected embryos were transferred in 58 cycles, resulting in 22 pregnancies, including fifteen clinical pregnancies. Up to now, 9 babies were born and 3 pregnancies are still ongoing. After a learning curve, our current PGD efficiency shows a total pregnancy rate per transfer of 60.0% and an implantation rate of 28.6%. Each PGD result was confirmed by prenatal or postnatal diagnosis. Our data demonstrate that PGD is a valid technique to allow couples at high risk of transmitting a genetic abnormality to increase their chances of a healthy pregnancy, but considering its complexity, patients must be counselled and selected rigorously.

Transportin-SR2 imports HIV into the nucleus

BACKGROUND

The human immunodeficiency virus type 1 (HIV-1) and other lentiviruses have the capacity to infect nondividing cells like macrophages. This requires import of the preintegration complex (PIC) through the nuclear pore. Although many cellular and viral determinants have been proposed, the mechanism leading to nuclear import is not yet understood.

RESULTS

Using yeast two-hybrid and pull-down, we identified and validated transportin-SR2 (TRN-SR2) as a bona fide binding partner of HIV-1 integrase. We confirmed the biological relevance of this interaction by RNAi. Depletion of TRN-SR2 interfered with the replication of HIV-1 and HIV-2 but not MoMLV in HeLaP4 cells. Knockdown of TRN-SR2 in primary macrophages likewise interfered with HIV-1 replication. Using Q-PCR, we pinpoint this block in replication to the early steps of the viral lifecycle. A reduction in 2-LTR formation suggests a block in PIC nuclear import upon siRNA-mediated knockdown. Different lines of evidence clearly proved that the late steps of viral replication are not affected. In an in vivo nuclear-import assay using labeled HIV-1 particles, the defect in nuclear import after depletion of TRN-SR2 was directly visualized. In comparison with control cell lines, the great majority of siRNA-treated cells did not contain any PIC in the nucleus.

CONCLUSION

Our data clearly demonstrate that TRN-SR2 is the nuclear-import factor of HIV.

Suv39H1 and HP1gamma are responsible for chromatin-mediated HIV-1 transcriptional silencing and post-integration latency

HIV-1 gene expression is the major determinant regulating the rate of virus replication and, consequently, AIDS progression. Following primary infection, most infected cells produce virus. However, a small population becomes latently infected and constitutes the viral reservoir. This stable viral reservoir seriously challenges the hope of complete viral eradication. Viewed in this context, it is critical to define the molecular mechanisms involved in the establishment of transcriptional latency and the reactivation of viral expression. We show that Suv39H1, HP1gamma and histone H3Lys9 trimethylation play a major role in chromatin-mediated repression of integrated HIV-1 gene expression. Suv39H1, HP1gamma and histone H3Lys9 trimethylation are reversibly associated with HIV-1 in a transcription-dependent manner. Finally, we show in different cellular models, including PBMCs from HIV-1-infected donors, that HIV-1 reactivation could be achieved after HP1gamma RNA interference.

[Single embryo transfer : impact of new Belgian legislation on the results of the Clinic of Fertility of the Erasme Hospital]

With the progress made in the treatments of assisted reproduction, implantation and pregnancy rates have increased. This evolution has led to increase the rates of multiple pregnancies in the general population. Considering maternal and fetal risks related to multiple pregnancies it was necessary to reduce their incidence. Several efforts have been tried, in particular the limitation of the number of embryos transferred to 2. This reduced the incidence of triplets but that of twin remained unchanged, which convinced the clinicians of the need to reduce further the number of embryo transfer. In Belgium a new policy of transfer was established by a law introduced since the 01/07/2003 aiming to reduce the costs related to the twin pregnancies and to increase the reimbursement of IVF treatments. We have studied the impact of this policy on the results at the clinic of Erasme. Two periods were compared : from 01/01/2001 to 30/06/2003 where the majority of the transfers was transfers of 2 embryos (56.8 %) and from 01/07/2003 to 31/12/2004 where the majority of the transfers was transfers of a single embryo (53.7 %) (p < 0.001). The rates of single embryo transfer were 12.5 % and 53.7 % respectively (p < 0.001). The rates of clinical pregnancies were 33.2 % and 27.3 % respectively (p < 0.001), on the other hand the percentage of twin pregnancies has strongly decreased from 29.9 % to 11.4 % (p < 0.001). The rate of frozen embryos has increased from 22 % policy seems to achieve its goals to the detriment of a reduction of the success rates. Nevertheless, the increase in the number of frozen embryos should allow, after thawing and transfer, to compensate at least partially this reduction of the pregnancy rate.

Options to preserve fertility before oncological treatment: cryopreservation of ovarian tissue and its clinical application

Chemotherapy and radiotherapy induce premature ovarian failure in many patients treated with these methods for oncological and benign diseases. This paper reviews the risk of developing premature ovarian failure according to the types of treatment as well as the different options to preserve fertility. We focus mainly on the cryopreservation of ovarian tissue procedure and we report here the second world-wide spontaneous pregnancy after cryopreserved ovarian tissue transplantation.

p300 Modulates ATF4 Stability and Transcriptional Activity Independently of Its Acetyltransferase Domain

ATF4 plays a crucial role in the cellular response to stress and multiple stress responses pathways converge to the translational up-regulation of ATF4. ATF4 is a substrate of the SCF(betaTrCP) ubiquitin ligase that binds to betaTrCP through phosphorylation on a DSGXXXS motif. We show here that ATF4 stability is also modulated by the histone acetyltransferase p300, which induces ATF4 stabilization by inhibiting its ubiquitination. Despite p300 acetylates ATF4, we found that p300-mediated ATF4 stabilization is independent of p300 catalytic activity, using either the inactive form of p300 or the acetylation mutant ATF4-K311R. ATF4 deleted of its p300 binding domain is no more stabilized by p300 nor recruited into nuclear speckles. In consequence of ATF4 stabilization, both p300 and the catalytically inactive enzyme increase ATF4 transcriptional activity.

Plasma homocysteine after insulin infusion in type II diabetic patients with and without methionine intolerance

BACKGROUND

A high prevalence of hyperhomocysteinemia has been reported in type II diabetic patients with documented vascular disease; hence the hypothesis that hyperhomocysteinemia may contribute to overall mortality in diabetic patients. The link between insulin and homocysteine metabolism has not been completely clarified yet; in particular, only few data are available on the effects of insulin in vivo on homocysteine metabolism in the presence of abnormalities of sulphur amino acid metabolism (methionine intolerance).

MATERIALS AND METHODS

To establish whether methionine intolerance and which of its determinants could influence total plasma homocysteine in response to insulin infusion in vivo in type II diabetic patients, we submitted 18 patients (Group A) with normal and 18 patients with abnormal (hyperhomocysteinemia) (Group B) response to oral methionine load to a glucose/clamp study. At time 0, and 30, 60 and 120 minutes after hyperinsulinemia, homocysteine and methionine plasma levels were assessed. In order to evaluate the cause of methionine intolerance, all patients were assayed for fasting homocysteine-cysteine ratio (as a marker of suspected heterozygosis for cystathionine-beta-synthase deficit), MTHFR C (677)T status and homocysteine-related vitamin status (serum vitamin B (6) [PLP], vitamin B (12) and folate).

RESULTS

After hyperinsulinemia, plasma methionine was reduced (by about - 30 % at 120 minutes vs. basal values) within both groups, whereas tHcy tend to decrease in group A following insulin administration (up to - 6.6 +/- 3.6 % vs. basal values at 120 minutes) with a significantly higher variability, while in patients with "methionine intolerance" (group B) tHcy tended to increase (up to + 29.05 +/- 8.3 % vs. basal values at 120 min from the clamp). Serum folic acid (7.45 +/- 2.8 vs. 4.82 +/- 2.5 nmol/L, p < 0.05), Vit. B (12) (348 +/- 78 vs. 242 +/- 65 pmol/L, p < 0.05) and PLP (84.1 +/- 23.6 vs. 50.6 +/- 32.4 nmol/L; p < 0.01) were significantly higher in group A than in group B; PLP levels significantly correlated with homocysteine after 4 h methionine load (n = 36; r = - 0.327, p < 0.05); group A showed also a significantly lower prevalence of suspected heterozygosis for cystathionine-beta-synthase deficit (1/18 [11.1 %] vs. 5/18 [33.3 %], p < 0.05) and MTHFR T allele presence (4/18 [22.2 %] vs. 11/18 [61.1 %], p < 0.01). A stepwise regression analysis with tHcy plasma level variations (event A = reduction; event B = increase) as the dependent variable showed that low serum folate and PLP levels and presence of MTHFR T allele were the variables associated with insulin-induced tHcy increase.

CONCLUSIONS

Methionine intolerance may influence the effect of insulin administration on plasma homocysteine in patients affected by type 2 diabetes. To prevent a possible acute (and repeated) hyperhomocysteinemia due to insulin administration in cases of methionine intolerance, it may be useful to assess the presence of methionine intolerance (tHcy after oral methionine loading) and Hcy-related vitamin status in all patients due to be subjected to insulin therapy.

A non-proteolytic role for ubiquitin in Tat-mediated transactivation of the HIV-1 promoter

The human immunodeficiency virus type 1 (HIV-1) encodes a potent transactivator, Tat, which functions through binding to a short leader RNA, called transactivation responsive element (TAR). Recent studies suggest that Tat activates the HIV-1 long terminal repeat (LTR), mainly by adapting co-activator complexes, such as p300, PCAF and the positive transcription elongation factor P-TEFb, to the promoter. Here, we show that the proto-oncoprotein Hdm2 interacts with Tat and mediates its ubiquitination in vitro and in vivo. In addition, Hdm2 is a positive regulator of Tat-mediated transactivation, indicating that the transcriptional properties of Tat are stimulated by ubiquitination. Fusion of ubiquitin to Tat bypasses the requirement of Hdm2 for efficient transactivation, supporting the notion that ubiquitin has a non-proteolytic function in Tat-mediated transactivation.

[The gynecology-obstetrics department]

The scientific and clinical activities of the Department of Obstetrics and Gynaecology have involved the three main subdivisions: the gynecological surgery, the obstetrics and fetal medicine, the endocrinology and the reproductive medicine. Minimal invasive surgery including laser assisted laparoscopy or robotic assisted surgery has been particularly developed. Endometriosis, a frequent and sometimes particularly invasive disease, and oncologic surgeries have been developed in collaboration with the digestive surgery department. The department has also contributed to the comprehension and treatment of prenatal pathologies such as premature labor and deliveries or the gestational diabetes. The department has supported the development of techniques to study the fetal well-being in utero: the prenatal echography, the chorionic villous sampling, the amniotic puncture or the cordocentesis for prenatal genetic diagnosis or fetal infectious contaminations, the CMV transmission more specifically. In endocrinology and reproductive medicine, the department has mainly developed the in vitro fertilization techniques. The prolonged embryo culture, the study of preimplantation embryo metabolism, the preimplantation genetic diagnosis and the cryopreservation of ovarian fragments to preserve fertility in women undergoing oncologic treatments represent the more recent developed topics. Finally, the security of viral transmission in assisted procreation and the treatment of these patients with chronic viral diseases (Hepatitis C or HIV) are another domain with important scientific activity.

Post-activation turn-off of NF-kappa B-dependent transcription is regulated by acetylation of p65

NF-kappaB represents a family of eukaryotic transcription factors participating in the regulation of various cellular genes involved in the immediate early processes of immune, acute-phase, and inflammatory responses. Cellular localization and consequently the transcriptional activity of NF-kappaB is tightly regulated by its partner IkappaBalpha. Here, we show that the p65 subunit of NF-kappaB is acetylated by both p300 and PCAF on lysines 122 and 123. Both HDAC2 and HDAC3 interact with p65, although only HDAC3 was able to deacetylate p65. Acetylation of p65 reduces its ability to bind kappaBeta-DNA. Finally, acetylation of p65 facilitated its removal from DNA and consequently its IkappaBetaalpha-mediated export from the nucleus. We propose that acetylation of p65 plays a key role in IkappaBetaalpha-mediated attenuation of NF-kappaBeta transcriptional activity which is an important process that restores the latent state in post-induced cells.

Differential acetylation of Tat coordinates its interaction with the co-activators cyclin T1 and PCAF

The HIV-1 transactivator protein, Tat, is an atypical transcriptional activator that functions through binding, not to DNA, but to a short leader RNA, TAR. Although details of its functional mechanism are still unknown, emerging findings suggest that Tat serves primarily to adapt co-activator complexes such as p300, PCAF and P-TEFb to the HIV-1 long terminal repeat. Hence, an understanding of how Tat interacts with these cofactors is crucial. It has recently been shown that acetylation at a single lysine, residue 50, regulated the association of Tat with PCAF. Here, we report that in the absence of Tat acetylation, PCAF binds to amino acids 20-40 within Tat. Interestingly, acetylation of Tat at Lys28 abrogates Tat-PCAF interaction. Acetylation at Lys50 creates a new site for binding to PCAF and dictates the formation of a ternary complex of Tat-PCAF-P-TEFb. Thus, differential lysine acetylation of Tat coordinates the interactions with its co-activators, cyclin T1 and PCAF. Our results may help in understanding the ordered recruitment of Tat co-activators to the HIV-1 promoter.

Preimplantation genetic diagnosis (PGD), a collaborative activity of clinical genetic departments and IVF centres

Preimplantation genetic diagnosis (PGD) requires the combined efforts of geneticists and workers in the field of reproductive medicine. This was studied on the basis of a questionnaire, sent to 35 members of the PGD Consortium of the European Society of Human Reproduction and Embryology (ESHRE). A reply was obtained from 20 centres. They represent the majority of activities in the field of PGD in the world. It is obvious that many of the activities (in vitro fertilisation, embryo culture and biopsy) take place in IVF units while others (counselling and diagnosis) are the responsibility of genetic diagnostic centres. The distances between both units vary considerably. In all but one centre sex determination is offered. Aneuploidy screening is offered in 13 out of 20 centres. PGD of translocations and other structural chromosome abnormalities is offered in all but one centre. The number of monogenic diseases offered varies considerably. In comparison to prenatal diagnosis PGD is more expensive. The majority of these costs are due to the IVF or ICSI procedure. The charges for PGD vary between about 600 euro and 4000 euro. In 16 out of 20 centres the parents to be must sign an informed consent form.

Interaction between cyclin T1 and SCF(SKP2) targets CDK9 for ubiquitination and degradation by the proteasome

CDK9 paired with cyclin T1 forms the human P-TEFb complex and stimulates productive transcription through phosphorylation of the RNA polymerase II C-terminal domain. Here we report that CDK9 is ubiquitinated and degraded by the proteasome whereas cyclin T1 is stable. SCF(SKP2) was recruited to CDK9/cyclin T1 via cyclin T1 in an interaction requiring its PEST domain. CDK9 ubiquitination was modulated by cyclin T1 and p45(SKP2). CDK9 accumulated in p45(SKP2-/-) cells, and its expression during the cell cycle was periodic. The transcriptional activity of CDK9/cyclin T1 on the class II major histocompatibility complex promoter could be regulated by CDK9 degradation in vivo. We propose a novel mechanism whereby recruitment of SCF(SKP2) is mediated by cyclin T1 while ubiquitination occurs exclusively on CDK9.

The periodic down regulation of Cyclin E gene expression from exit of mitosis to end of G(1) is controlled by a deacetylase- and E2F-associated bipartite repressor element

The expression of cyclin E and that of a few other bona fide cell cycle regulatory genes periodically oscillates every cycle in proliferating cells. Although numerous experiments have documented the role of E2F sites and E2F activities in the control of these genes as cells exit from G(0) to move through the initial G(1)/S phase transition, almost nothing is known on the role of E2Fs during the subsequent cell cycles. Here we show that a variant E2F-site that is part of the Cyclin E Repressor Module (CERM) (Le Cam et al., 1999b) accounts for the periodic down regulation of the cyclin E promoter observed between the exit from mitosis until the mid/late G(1) phase in exponentially cycling cells. This cell cycle-dependent repression correlates with the periodic binding of an atypical G(1)-specific high molecular weight p107-E2F complex (Cyclin E Repressor Complex: CERC2) that differs in both size and DNA binding behaviors from known p107-E2F complexes. Notably, affinity purified CERC2 displays a TSA-sensitive histone deacetylase activity and, consistent with this, derepression of the cyclin E promoter by trichostatin A depends on the CERM element. Altogether, this shows that the cell cycle-dependent control of cyclin E promoter in cycling cells is embroiled in acetylation pathways via the CERM-like E2F element.

Evidence of reduced single-stranded testicular sperm DNA from obstructive azoospermic men after 3 days of in-vitro culture

The aim of the present study was to verify whether culturing testicular tissue, to obtain a higher percentage of motile spermatozoa and a better post-thaw recovery rate, affected the ratio between single/double-stranded sperm DNA and, consequently, DNA sensitivity to damage. Testicular biopsy samples from men with obstructive and secretory azoospermia, candidates for assisted reproductive treatment, were cultured for 72 h. The percentage of motile spermatozoa and the single/double stranded DNA ratio were assessed on the day of retrieval (day 0) and again on day 3. The single/double stranded DNA ratio was measured by the acridine orange (AO) staining method. Spermatozoa were classified as green (double-stranded chromatin) or red fluorescing (single-stranded chromatin). In obstructive azoospermia, median motility was 22% (range 10-44%) on day 0 and 50% (range 38-63%) on day 3 (P < 0.01). The median percentage of red stained spermatozoa was 53.5% (range 0.1-88%) on day 0 and 20% (range 2.7-99.9%) on day 3 (P < 0.05). No changes were observed in secretory azoospermia. The culture procedure from obstructive azoospermia not only increased the post-thaw recovery rate, as previously observed, but also reduced the portion of spermatozoa containing single-stranded DNA, thereby increasing the availability of double-stranded DNA spermatozoa for ICSI use.

Amino acids promote human blastocyst development in vitro

Supplementation of culture media with amino acids has been shown to benefit preimplantation embryo development in several species. This randomized study analysed the in-vitro development of human embryos obtained after IVF in the presence or absence of a combination of amino acids from the 2- to 4-cell stage to the blastocyst stage. A total of 129 human embryos was randomly distributed between three serum-free chemically defined sequential media: (i) glucose-free Earle's balanced salt solution (EBSS) with glutamine (Gln) prior to morula stage, supplemented with glucose for blastocyst formation; (ii) glucose-free EBSS with glutamine and non-essential amino acids (AA) for cleavage stage development, and supplemented with all 20 AA for blastocyst formation (Earle's+AA); and (iii) a sequential commercial medium containing amino acids (K-SCIM). Embryos were individually cultured for successive periods of 24 h. On day 6 of development, blastocysts were differentially labelled and the numbers of trophectoderm and inner cell mass cells, mitoses and dead cells were examined. Blastocyst development was similar for the three sequential media. The mixture of AA significantly increased total blastocyst cell numbers from 61.8 +/- 4.2 with Earle's+Gln to 99.3 +/- 8.4 with Earle's+AA and 100.2 +/- 9.4 with K-SCIM (P = 0.005). This increase was present in both the trophectoderm and inner cell mass lineages (P < 0.02). Furthermore, the dead cell index was significantly lower with Earle's+AA (P = 0.047).

Re-analysis by fluorescence in situ hybridisation of spare embryos cultured until Day 5 after preimplantation genetic diagnosis for a 47, XYY infertile patient demonstrates a high incidence of diploid mosaic embryos: a case report

Mosaicism in 4-8-cell human embryos analysed by fluorescence in situ hybridisation (FISH) has been widely reported, but few studies have addressed the incidence of mosaicism in more advanced embryonic stages. In the present study we analysed spare human embryos in a case of preimplantation genetic diagnosis (PGD) for increased risk of aneuploidy because of an infertile 47,XYY man. After replacement of two embryos typed as 1818XX at PGD, six spare embryos (not frozen because of their low quality) were re-analysed on Day 5 for PGD confirmation. Out of five embryos typed as 1818XY at PGD, four were diploid mosaic (DM) and one was normal in all cells. The sixth embryo, typed as 18XYY/1818181818X at PGD, was a DM. In spite of the bias of our small series of morphologically low-quality embryos, the surprisingly high proportion of mosaics (which confirms previous findings) questions the validity of PGD, but supports the strategy of transferring only the embryos where two blastomeres gave normal and concordant results at PGD. More data are required to understand the clinical significance of early diploid mosaicism (and its impact on implantation rate) and to determine whether some diploid mosaic embryos might be considered safe for transfer.

Increased sperm motility after in-vitro culture of testicular biopsies from obstructive azoospermic patients results in better post-thaw recovery rate

The objective of this study was to optimize the use of testicular biopsies in 14 patients with obstructive azoospermia. Testicular specimens were retrieved from six patients (group I) and cultured at 32 and 37 degrees C for up to 20 days; changes in percentage motile spermatozoa were compared. In four men of group I, one portion of the specimen was frozen at retrieval, and changes in post-thaw motility after 24 h of culture at 37 degrees C were recorded. In the other eight patients (group II), testicular specimens were frozen at retrieval and after 72 h culture at 37 degrees C. Pre and post-freezing motility and post-thaw recovery rate were compared. No significant differences were observed until day 8 in the improvement of motility between 32 and 37 degrees C in-vitro culture. Maximum motility was reached, under both conditions, between 48 h and 72 h. Post-thaw 24 h culture at 37 degrees C of specimens frozen at retrieval did not improve motility; however, 72 h pre-freezing culture significantly improved initial motility (P: < 0.01), post-thaw motility (P: < 0.01) and post-thaw recovery rate (P: < 0. 001). The higher recovery rate of samples frozen 3 days after retrieval allows more economical use of the tissue that is available.

Comparison of ethylene glycol, 1,2-propanediol and glycerol for cryopreservation of slow-cooled mouse zygotes, 4-cell embryos and blastocysts

The aim of the study was to analyse the toxicity, the osmolar and cryoprotective activity of ethylene glycol (ETG) in terms of survival rate (SR), cleavage rate (CR) and expanded blastocysts percentage (EBP) of mouse embryos. Early mouse embryos and blastocysts were slowly cooled with ETG, 1,2-propanediol (PROH) or glycerol, and thawed. The Van t'Hoff curve for 1.5 mol/l ETG showed recovery of initial volume within 4 min. No differences were observed in CR and EBP of ETG-exposed compared with non-exposed mouse zygotes. The SR of zygotes frozen with PROH was significantly better than with ETG (92% and 60% respectively; P < 0.01), and a significantly better EBP was achieved for blastocysts frozen with glycerol compared with ETG (75% and 50% respectively; P < 0.05). For 4-cell stage embryos, no differences were observed in SR and EBP between ETG and PROH. Higher EBP was observed for 4-cell stage embryos (53%) frozen with ETG compared with pronucleate stage (19%) and blastocysts (48%). Low toxicity, good SR and EBP were observed for mouse embryos frozen with ETG, the best results being obtained at the 4-cell stage. At other embryonic stages, PROH and glycerol respectively seemed to provide better results.

Acetylation of the HIV-1 Tat protein by p300 is important for its transcriptional activity

The human immunodeficiency virus 1 (HIV-1) Tat protein activates transcriptional elongation by recruiting the positive transcription elongation factor (pTEFb) complex to the TAR RNA element, which is located at the 5' extremity of all viral transcripts [1-3]. Tat also associates in vitro and in vivo with the transcriptional coactivator p300/CBP [4-6]. This association has been proposed to recruit the histone acetyltransferase (HAT) activity of p300 to the integrated HIV-1 promoter. We have observed that the purified p300 HAT domain acetylates recombinant Tat proteins in vitro and that Tat is acetylated in vivo. The major targets of acetylation by p300 are lysine residues (Lys50 and Lys51) in the arginine-rich motif (ARM) used by Tat to bind RNA and for nuclear import. Mutation of these residues in full-length recombinant Tat blocked its acetylation in vitro. Furthermore, mutation of these lysine residues to arginine markedly decreased the synergistic activation of he HIV promoter by Tat and p300 or by Tat and cyclin T1. These results demonstrate that acetylation of Tat by p300/CBP is important for its transcriptional activation of the HIV promoter.

[Impact of the introduction of intracytoplasmic sperm injection (ICSI) on the treatment of severe male sterility]

The introduction of the Intracytoplasmic Single Sperm Injection (ICSI) has been a turning point for the treatment of severe male infertility. ICSI allowed not only to reduce fertilization failure from 35% to 0.7% but created at the same time the opportunity for a group of patients with extremely low sperm counts to procreate. The discovery that breaking the tail of the spermatozoon prior to the injection was the most important step is at the origin of major improvements: fertilization increased from 22% to 77%, pregnancy rate from 16% to 54% and the implantation rate from 7.4% to 26%. From October 1994 to April 1999, 835 ICSI cycles were performed and resulted in 312 ongoing pregnancies (37%), fertilization rate was 75%, with a fertilization failure of only 0.7%. The use of ICSI and IVF on sibling oocytes for semen samples with doubtful fertilizing ability clearly illustrated the superiority of ICSI. No fertilization failures occurred after ICSI and the fertilization rate was 76% versus 27.8% (P < 0.01). Similar benefit of ICSI was shown for crytozoospermia up to then a hopeless situation. A total of 26 pregnancies were obtained out of 87 cycles with a fertilization rate of 58.8%. Similar results were obtained when ICSI was combined with testicular sperm, 20 pregnancies occurred after from 46 transfers (43%) including cycles with cryopreserved testicular sperm. It is now clear that ICSI is the method of choice for the treatment of severe male infertility.

[Diminishing the risk of multiple pregnancies in in vitro fertilization: from selective transfer of two embryos to that of one blastocyst?]

The risk of multiple pregnancy after IVF needs to be drastically reduced. Several policies can be applied including the transfer of a maximum of three embryos to all patients, the fertilization of a maximum of three oocytes or a selective reduction of the number of transferred embryos. The first policy previously applied at the Fertility Clinic at Erasme Hospital until 1996, transferred two good quality embryos to patients with at least three good embryos. If this policy demonstrated that patients with two transferred embryos had similar chances of pregnancies compared to patients with three transferred embryos, it failed to sufficiently decrease the number of multiple pregnancies. The second policy applied since 1997, transferring a maximum of two average or good embryos to all patients aged under 35 years and with less than 3 previous attempts, demonstrated that while preserving the chances of pregnancy for these patients, it decreased by 20% the number of multiple pregnancies and almost eliminated triplets. With the improvement of culture media, it is now possible to culture embryos in vitro for a longer period and therefore transfer embryos with proven viability at a time corresponding more to in vivo physiological conditions. The implantation rates for these embryos, for patients with at least 4 previous attempts can reach 40%. If these results persist, it would be possible to transfer blastocysts to all patients and perhaps move on to the replacement of a single embryo, a policy that will practically eradicate all multiple pregnancies.

[Aspects of scientific research and technical progress in human fertility]

The development of an outstanding in vitro fertilization program greatly benefits from the contribution of research because it remains an unfailing source of questions on human reproduction, as much in the fields of physiology and pathology as in those of psychology and sociology. This paper shows five major themes that are tackled by the laboratory of biology and psychology of human fertility and the Fertility Clinic, whether it's endocrinology (the ovarian renin and angiotensin regulation), cellular metabolism (embryo metabolism), genetics (preimplantation genetic diagnosis) or cancerology (ovarian tissue conservation before or after chemo- or radiotherapy), all of these are crossed by the fifth (the psychological and ethical aspects of in vitro fertilization) which gives a human dimension to the biological work, since it's a very special biology that it's our own reproduction, the very base of the specie's survival.

[In vitro fertilization at the Erasme Hospital: 10 years and 1000 pregnancies later...]

This contribution summarize ten years of in vitro fertilization of clinical work. Activity growth, improvements of results (mean fertilization rate increased from 45% to 58%, fertilization failure dropped from 18% to 7%, pregnancy chances gains 9% to reach 44% per trial) and new treatments possibilities (severe male infertility) thanks to the ICSI technic were the major characteristics of this last ten years. The original anonymous oocyte donation program with donors permutation initiated as soon as 1990 has imposed itself due to it's exceptional efficiency with a pregnancy rate of 95% per oocyte pick up on a population of 46 donors and 145 recipient cycles. Thanks to the large population studied (4028 cycles, 1071 pregnancies), the tendencies in human fecundity (impact of age) and the risks linked to multiples pregnancies could be highlighted, stressing the importance of future developments presented in the other contributions following this general presentation of results.

The outcome of cryopreserved human embryos after intracytoplasmic sperm injection and traditional IVF

OBJECTIVE

Our objective was to analyze the outcome of cryopreserved embryos obtained after intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) in terms of survival rate, implantation rate (IR), total and clinical pregnancy rate (PR) in a retrospective, comparative study.

METHODS

Three hundred seventy-five IVF and 463 ICSI surnumerary cleaved embryos, frozen on Day 2 with 1,2-propanediol, were thawed.

RESULTS

Thirty-two percent of the thawed IVF embryos survived and 11 pregnancies (8 clinical) were obtained from 68 transfers (16.1%). Fourty-seven percent of the ICSI embryos survived, with 19 pregnancies (18 clinical) from 116 transfers (16.4%). The IR was 8.5% (8/94) in IVF cycles and 10.8% (20/185) in ICSI cycles.

CONCLUSIONS

A significantly better survival rate of ICSI embryos was observed but with no difference in PR, preclinical, and clinical abortion rate, or IR.

Randomized autocontrolled comparison of the embryo culture performance of Nunc and Falcon petri dishes

PURPOSE

Our purpose was to compare the embryo culture performance of two types of petri dishes (Nunc and Falcon).

METHODS

Mouse zygotes were cultured up to the expanded blastocyst stage in both types of dishes. The oocytes from 50 in vitro fertilization cycles were randomly divided between the two types of dishes. Fertilization, cleavage, and embryo quality were compared. Oocytes from another 50 cycles were all cultured at random in either type of dish. Pregnancy and implantation rates were compared between the two types.

RESULTS

Of 91 mouse zygotes, 81 cleaved to two-cell-stage embryos, and 64 became expanded blastocysts in Falcon dishes; of 99 zygotes, 81 cleaved to two-cell-stage embryos and 66 became expanded blastocysts in Nunc dishes. Of 248 oocyte-cumulus complexes (OCC), 145 fertilized in Falcon dishes, and of 269 OCC, 175 fertilized in Nunc dishes. The high quality embryo ratio was 51 out of 118 in Falcon dishes, not different from that in Nunc dishes, 58 out of 139. In Falcon dishes 72 out of 118 embryos were at least at the four-cell stage after 45 hr, versus 70 out of 139 in Nunc dishes. Twenty-three clinical pregnancies were obtained in the first 50 cycles with sibling oocytes. In the second group, with randomization of the cycles between Nunc and Falcon, 8 pregnancies were obtained in the Nunc and 10 in the Falcon dishes. The implantation rate in this second group of 50 cycles was 9 out of 61 in Falcon and 11 out of 57 in Nunc dishes.

A new family of human histone deacetylases related to Saccharomyces cerevisiae HDA1p

Histone deacetylases are the catalytic subunits of multiprotein complexes that are targeted to specific promoters through their interaction with sequence-specific DNA-binding factors. We have cloned and characterized a new human cDNA, HDAC-A, with homology to the yeast HDA1 family of histone deacetylases. Analysis of the predicted amino acid sequence of HDAC-A revealed an open reading frame of 967 amino acids containing two domains: a NH2-terminal domain with no homology to known proteins and a COOH-terminal domain with homology to known histone deacetylases (42% similarity to RPD3, 60% similarity to HDA1). Three additional human cDNAs with high homology to HDAC-A were identified in sequence data bases, indicating that HDAC-A itself is a member of a new family of human histone deacetylases. The mRNA encoding HDAC-A was differentially expressed in a variety of human tissues. The expressed protein, HDAC-Ap, exhibited histone deacetylase activity and this activity mapped to the COOH-terminal region (amino acids 495-967) with homology to HDA1p. In immunoprecipitation experiments, HDAC-A interacted specifically with several cellular proteins, indicating that it might be part of a larger multiprotein complex.

Genomic organization and chromosomal localization of the human histone deacetylase 3 gene

Reversible acetylation of histone proteins plays a critical role in transcriptional regulation, cell cycle progression, and developmental events. The steady state of histone acetylation is controlled by the enzymatic activities of multiple histone acetyltransferases and histone deacetylases (HDACs). Three distinct human HDACs are homologous to RPD3, a yeast transcriptional regulator. We have isolated and sequenced a genomic clone for the human HDAC3 gene. This is a single-copy gene spanning a region of at least 13 kb. Determination of the intron-exon splice junctions established that the gene is encoded by 15 exons ranging in size from 56 to 657 bp. Fluorescence in situ hybridization studies localized this gene to 5q31. Double-target experiments in which both HDAC3 and the early-growth response 1 gene (EGR1), which is localized in the 5q31.2 region, were used as probes showed that the HDAC3 gene lies in region 5q31.3, immediately distal to EGR1 with respect to the centromere.

Comparison of two elective transfer policies of two embryos to reduce multiple pregnancies without impairing pregnancy rates

A first elective transfer policy of two embryos based solely on embryo morphology was compared to a more restrictive policy transferring two embryos to all patients aged < 35 years with less than three previous cycles to reduce the incidence of multiple pregnancies. With a significant reduction in the number of triple transfers from 72.4 to 44.3%, the delivery rates were similar for both policies, 31 and 32.1%. However, the multiple pregnancy rates per transfer significantly decreased from 12.5 to 7.8% (P < 0.05). Of 99 pregnancies, only 24.2% were multiple including 1% of triplets compared to 40.7% multiple pregnancies including 6.7% of triplets for the first policy. Forty-eight transfers of two average embryos with the new policy were compared to 264 transfers of three average embryos with the old policy. Multiple pregnancy rates per transfer were significantly reduced by a third from 23 to 8% (P < 0.05) without a reduction of the pregnancy rates (42 and 48%). This study demonstrated that elective transfer of two embryos reduced the number of multiple pregnancies without impairing the pregnancy rates even with the transfer of average embryos.

A first prospective study of the individual straight line velocity of the spermatozoon and its influences on the fertilization rate after intracytoplasmic sperm injection

The straight line velocity of 500 individual spermatozoa was measured immediately before their direct injection into the cytoplasm of 500 metaphase II oocytes. The straight line velocity (VSL) did not have a normal distribution (P < 0.01) and ranged between 0 and 35 microm/s. The fertilization rate (84%) was significantly (P < 0.008) higher in the quartile of the sperm population with the highest VSL compared to the fertilization rate (68%) in the quartile with the lowest VSL. Embryo cleavage and embryo quality were not different in the quartiles of the sperm population used for injection.

A class of hybrid polar inducers of transformed cell differentiation inhibits histone deacetylases

Hybrid polar compounds (HPCs) have been synthesized that induce terminal differentiation and/or apoptosis in various transformed cells. We have previously reported on the development of the second-generation HPCs suberoylanilide hydroxamic acid (SAHA) and m-carboxycinnamic acid bishydroxamide (CBHA) that are 2,000-fold more potent inducers on a molar basis than the prototype HPC hexamethylene bisacetamide (HMBA). Herein we report that CBHA and SAHA inhibit histone deacetylase 1 (HDAC1) and histone deacetylase 3 (HDAC3) activity in vitro. Treatment of cells in culture with SAHA results in a marked hyperacetylation of histone H4, but culture with HMBA does not. Murine erythroleukemia cells developed for resistance to SAHA are cross-resistant to trichostatin A, a known deacetylase inhibitor and differentiation inducer, but are not cross-resistant to HMBA. These studies show that the second-generation HPCs, unlike HMBA, are potent inhibitors of HDAC activity. In this sense, HMBA and the second-generation HPCs appear to induce differentiation by different pathways.

Characterization of a human RPD3 ortholog, HDAC3

Histone acetylation levels in cells result from a dynamic equilibrium between competing histone acetylases and deacetylases. Changes in histone acetylation levels occur during both transcriptional activation and silencing. Cloning of the cDNA for a human histone deacetylase (HDAC1) has shown that it represents a human ortholog of the yeast transcriptional regulator RPD3. We have screened the expressed sequence tag database (National Center for Biotechnology Information) with the yeast RPD3 sequence and identified a human ortholog of RPD3, HDAC3. This cDNA encodes a protein of 428 amino acids with 58% sequence identity with HDAC1p. By using a specific polyclonal antiserum recognizing the C-terminal domain of HDAC3p and Western blotting, we detected a single approximately 49-kDa band in several tumor cell lines. HDAC3p is expressed predominantly in the nuclear compartment. Immunoprecipitation experiments with either an antiserum against HDAC3p or an anti-FLAG antiserum and a flagged HDAC3 cDNA showed that HDAc3p exhibits deacetylase activity both on free histones and on purified nucleosomes. This deacetylase activity is inhibited by trichostatin, trapoxin, and butyrate in vitro to the same degree as the deacetylase activity associated to HDAC1p. These observations identify another member of a growing family of human HDAC genes.

Mutations in the tat gene are responsible for human immunodeficiency virus type 1 postintegration latency in the U1 cell line

Previous reports have demonstrated that the U1 cell line, a model for postintegration latency, is defective at the level of Tat function and can be rescued by exogenously provided Tat protein. Sequence analysis of tat cDNAs from the U1 cell line identified two distinct forms of Tat, in agreement with the fact that this cell line contains two integrated human immunodeficiency (HIV) proviruses. One Tat cDNA lacked an ATG initiation codon, while the other contained an H-to-L mutation at amino acid 13 (H13-->L). Both tat cDNAs were defective in terms of transcriptional activation of long terminal repeat-luciferase reporter gene in transient-transfection experiments. Introduction of the H13-->L mutation in a wild-type tat background caused a severe reduction in transcriptional activation. Introduction of the same mutation in an infectious HIV molecular clone caused a severely defective phenotype which could be rescued when the HIV proviral DNA was transfected in a Jurkat cell line stably expressing the Tat protein (Jurkat-Tat) or in Jurkat cells treated with tumor necrosis factor alpha. Infectious virus stocks generated in Jurkat-Tat cells were used to infect Jurkat cells and exhibited severely impaired growth which could also be rescued by infecting Jurkat-Tat cells. These observations define tat mutations as a mechanism for HIV postintegration latency.

Nitric oxide in preeclampsia: lack of evidence for decreased production

The purpose of our study was to determine the involvement of the L-arginine-NO system in preeclampsia. We studied 26 patients with preeclampsia and 27 normotensive pregnancies. Maternal and cord plasma, urine and amniotic fluid were assayed for nitric oxide metabolites (nitrite and nitrate) using the Griess reaction. Sections of placenta and fetal membranes were immunostained with polyclonal anti-endothelial and anti-neuronal nitric oxide synthase antibodies. The concentration of nitrate in the amniotic fluid of preeclamptic patients (median 10.3 mumol/mg creatinine) was significantly higher (P < 0.001) than in the normotensive group (5.6 mumol/mg creatinine). Nitrate concentrations in maternal and cord plasma and in urine were similar in the two groups. Endothelial cells of the villi of preeclamptic placentas showed a higher positivity in endothelial nitric oxide synthase immunostaining with respect to normotensive controls. Our results indicate that feto-placental NO production is not reduced in preeclampsia. In contrast, the increased concentrations of NO metabolites in amniotic fluid and the positive immunostaining of endothelial nitric oxide synthase in the placental villi suggest that the placental L-arginine-NO system is up-regulated in preeclampsia.

Transcription factor binding sites downstream of the human immunodeficiency virus type 1 transcription start site are important for virus infectivity

When transcriptionally active, the human immunodeficiency virus (HIV) promoter contains a nucleosome-free region encompassing both the promoter/enhancer region and a large region (255 nucleotides [nt]) downstream of the transcription start site. We have previously identified new binding sites for transcription factors downstream of the transcription start site (nt 465 to 720): three AP-1 sites (I, II, and III), an AP3-like motif (AP3-L), a downstream binding factor (DBF) site, and juxtaposed Sp1 sites. Here, we show that the DBF site is an interferon-responsive factor (IRF) binding site and that the AP3-L motif binds the T-cell-specific factor NF-AT. Mutations that abolish the binding of each factor to its cognate site are introduced in an infectious HIV-1 molecular clone to study their effect on HIV-1 transcription and replication. Individual mutation of the DBF or AP3-L site as well as the double mutation AP-1(III)/AP3-L did not affect HIV-1 replication compared to that of the wild-type virus. In contrast, proviruses carrying mutations in the Sp1 sites were totally defective in terms of replication. Virus production occurred with slightly delayed kinetics for viruses containing combined mutations in the AP-1(III), AP3-L, and DBF sites and in the AP3-L and DBF-sites, whereas viruses mutated in the AP-1(I,II,III) and AP3-L sites and in the AP-1(I,II,III), AP3-L, and DBF sites exhibited a severely defective replicative phenotype. No RNA-packaging defect could be measured for any of the mutant viruses as determined by quantification of their HIV genomic RNA. Measurement of the transcriptional activity of the HIV-1 promoter after transient transfection of the HIV-1 provirus DNA or of long terminal repeat-luciferase constructs showed a positive correlation between the transcriptional and the replication defects for most mutants.

[Modification of in vitro insemination techniques in the treatment of severe male factors in assisted reproduction]

The aim of this study is to detect qualified in vitro insemination techniques in the treatment of the severe oligoasthenotheratospermia which is defined as total motile count in the pretreatment samples (< 5 x 10(6) with > 50% of abnormal morphology). These patients have taken part in the in vitro insemination program of the Assisted Reproduction Unit of the 2nd Department of Obstetrics and Gynecology at Rome University "La Sapienza" during a period between June and December 1995. Several modifications of the standard in vitro techniques have been developed such as: mechanical decumulation of the oocytes, reduction of the volume of culture medium, increase of spermatozoa and oocyte concentration at the moment of insemination. A good fertilization rate was achieved (33%) as regard to the semen sample and procedures utilized. Twelve Ets were performed and 4 clinical pregnancies (25% per patients and 33% per transfer) were achieved. These data demonstrate that by the modification of standard laboratory methods for in vitro insemination, a good fertilization rate and a high clinical pregnancy rate can be achieved in cases of severe male factor infertility without having to resort to micromanipulation techniques.

Immune hyperactivation of HIV-1-infected T cells mediated by Tat and the CD28 pathway

Human immunodeficiency virus-type 1 (HIV-1) infection is characterized by a chronic state of immune hyperactivation in patients. Infection of human peripheral blood lymphocytes with HIV-1 in vitro resulted in increased interleukin-2 (IL-2) secretion in response to T cell activation via the CD3 and CD28 receptors. Expression of the HIV-1 transactivator Tat recapitulated this phenotype and was associated with increased IL-2 secretion in response to costimulation with CD3 plus CD28. IL-2 superinduction by Tat occurred at the transcriptional level, was mediated by the CD28-responsive element in the IL-2 promoter, and was exclusively dependent on the 29 amino acids encoded by the second exon of Tat.