Different tether proteins of the same membrane contact site affect the localization and mobility of each other.

Membrane contact sites enable the exchange of metabolites between subcellular compartments and regulate organelle dynamics and positioning. These structures often contain multiple proteins that tether the membranes, establishing the apposition and functionalizing the structure. In this work, we used drug-inducible tethers in vivo in Saccharomyces cerevisiae to address how different tethers influence each other. We found that the establishment of a region of membrane proximity can recruit tethers, influencing their distribution between different locations or protein complexes. In addition, restricting the localization of one tether to a subdomain of an organelle caused other tethers to be restricted there. Finally, we show that the mobility of contact site tethers can also be influenced by other tethers of the same interface. Overall, our results show that the presence of other tethers at contact sites is an important determinant of the behavior of tethering proteins. This suggests that contact sites with multiple tethers are controlled by the interplay between specific molecular interactions and the cross-influence of tethers of the same interface.

TCR Sequencing Reveals the Distinct Development of Fetal and Adult Human Vγ9Vδ2 T Cells.

Phosphoantigen-reactive Vγ9Vδ2 T cells represent the main innate human γδ T cell subset and dominate the fetal and adult peripheral blood γδ T cell repertoire. It has been hypothesized that adult blood Vγ9Vδ2 T cells find their origin in the fetus like it is established for mouse innate γδ T cells. To address this issue, we analyzed the CDR3 of the TCR of human blood and thymic Vγ9Vδ2 T cells from fetal until adult life. We first identified key differences in the CDR3 repertoire of fetal and adult blood Vγ9Vδ2 T cells, including in CDR3 features important for phosphoantigen reactivity. Next, we showed that most of these key adult CDR3 features were already present in the postnatal thymus and were further enhanced upon selection in vitro by the microbial-derived phosphoantigen (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate. Finally, we demonstrated that the generation of a fetal-type or adult-type Vγ9Vδ2 CDR3 repertoire is determined by the fetal and postnatal nature of the hematopoietic stem and precursor cell. Thus, our data indicate that fetal blood Vγ9Vδ2 T cells find their origin in the fetal thymus whereas adult blood Vγ9Vδ2 T cells are generated to a large degree independently after birth.

Atopobium vaginae intrapartum bacteremia: A case report with a literature review.

Atopobium vaginae is an anaerobic Gram-positive bacterium recognized as a causative agent of bacterial vaginosis and associated with preterm delivery. Invasive infection and bacteremia have been rarely reported. We describe the case of a woman expecting her firstborn child who presented with a A. vaginae bacteremia during labor. Identification was performed using 16S rRNA gene sequencing. Both maternal and fetal outcomes were favorable due to the maternal treatment with amoxicillin-clavulanic acid. We identified three other cases in the literature with different fetal outcome. The genetic diversity of A. vaginae should be further explored in order to reveal potential strains with differential pathogenic potential.

HIV-related immune activation attenuates polyfunctional IgG and memory B-cell responses to Tdap immunization during pregnancy.

BACKGROUND: Maternal pertussis vaccination with Tdap vaccine is recommended to protect newborns from severe postnatal infection. HIV-exposed uninfected (HEU) infants have a higher incidence of pertussis infection and may particularly benefit from maternal immunization. The impact of HIV infection on the quality of IgG and memory B cell (MBC) responses to Tdap vaccination in pregnant women (PW) living with HIV (PWH) is unknown. METHODS: In this observational study, humoral immune responses to Tdap vaccination, including IgG levels, Fc-dependent effector functions, and MBC frequencies, were measured before and after vaccination in 40 PWH and 42 HIV-uninfected PW. Placental transfer of IgG and avidity were assessed in cord blood (CB). Soluble and cellular immune activation markers were quantified at baseline. FINDINGS: One month after vaccination, PWH had lower frequencies of MBC compared with HIV-uninfected PW. At delivery, PWH had attenuated pertussis-specific IgG levels and Fc-dependent effector functions. Reduced levels of maternal vaccine polyfunctional IgG and IgG avidity were transferred to HEU as compared to HIV-unexposed newborns. After adjustment with ethnicity, maternal antibody levels and gestational age at vaccination, HIV infection was independently associated with decreased levels of PT specific-IgG in CB. Both maternal and neonatal pertussis-specific IgG responses as well as PT-specific IgG avidity were inversely correlated with maternal sCD14 levels before vaccination among PWH. INTERPRETATION: Maternal HIV infection is associated with attenuated humoral immune responses to Tdap vaccination that correlate with sCD14. Suboptimal transfer of maternal immunity may further increase the risk of severe pertussis infection in HEU infants. FUNDING: This work was supported by IRIS Fund managed by the Foundation Roi Baudouin [2017J1820690206902], Association Vésale pour la Recherche Médicale and the Medical Council of CHU Saint-Pierre and has been funded in part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, US Department of Health and Human Services, under Award No. U19AI145825. N.D. is a clinical researcher and A.M. is Research Director at the Fonds de la Recherche Scientifique (F.R.S.-FNRS), Belgium. M.E.A. was partially supported by NIHNIAID1U19AI14825. This article is published with the support of the Fondation Universitaire of Belgium.

Impact of pregnancy on polyfunctional IgG and memory B cell responses to Tdap immunization.

BACKGROUND: Maternal pertussis immunization using Tdap vaccine is recommended in many countries to protect newborns from severe post-natal infection. Immunological changes during pregnancy may influence the response to vaccines. The quality of IgG and memory B cell responses to Tdap immunization in pregnant women has not yet been described. METHODS: The impact of pregnancy on the response to Tdap vaccination was assessed by comparing humoral immune responses in 42 pregnant and 39 non-pregnant women. The levels of serum pertussis antigens and tetanus toxoid-specific IgG, IgG subclasses, IgG Fc-mediated effector functions, as well as memory B cell frequencies were assessed before and at several time points after vaccination. RESULTS: Tdap immunization induced similar levels of pertussis and tetanus-specific IgG and IgG subclasses in pregnant and non-pregnant women. Pregnant women produced IgG promoting complement deposition, and neutrophils and macrophages phagocytosis at levels comparable to non-pregnant women. They were also able to expand pertussis and tetanus-specific memory B cells at similar frequencies as non-pregnant women, suggesting equivalent "boostability". Higher levels of vaccine-specific IgG, IgG subclasses, and IgG Fc-mediated effector functions were detected in cord blood as compared to maternal blood, indicating efficient transport across the placenta. CONCLUSIONS: This study demonstrates that pregnancy does not affect the quality of effector IgG and memory B cell responses to Tdap immunization and that polyfunctional IgG are efficiently transferred across the placenta. REGISTRY'S URL AND THE TRIAL'S REGISTRATION NUMBER: ClinicalTrials.Gov (NCT03519373).

Multiple tethers of organelle contact sites are involved in α-synuclein toxicity in yeast.

The protein α-synuclein (α-syn) is one of the major factors linked to Parkinson's disease, yet how its misfolding and deposition contribute to the pathology remains largely elusive. Recently, contact sites among organelles were implicated in the development of this disease. Here, we used the budding yeast Saccharomyces cerevisiae, in which organelle contact sites have been characterized extensively, as a model to investigate their role in α-syn cytotoxicity. We observed that lack of specific tethers that anchor the endoplasmic reticulum to the plasma membrane resulted in cells with increased resistance to α-syn expression. Additionally, we found that strains lacking two dual-function proteins involved in contact sites, Mdm10 and Vps39, were resistant to the expression of α-syn. In the case of Mdm10, we found that this is related to its function in mitochondrial protein biogenesis and not to its role as a contact site tether. In contrast, both functions of Vps39, in vesicular transport and as a tether of the vacuole-mitochondria contact site, were required to support α-syn toxicity. Overall, our findings support that interorganelle communication through membrane contact sites is highly relevant for α-syn-mediated toxicity.

An audit about labour induction, using prostaglandin, in women with a scarred uterus.

OBJECTIVES: Induction of labour after a previous caesarean section is still controversial. We aim to analyse, in a population of women who have a uterine scar, the maternal, foetal and neonatal complications in relation to the mode of labour and delivery. STUDY DESIGN: Retrospective analysis of collected data from all the singleton deliveries of patients with a scarred uterus (N=798), admitted to the hospital between August 2006 and March 2009. OUTCOMES: maternal and perinatal complications. RESULTS: Among 798 singleton deliveries, 36.1% had a spontaneous labour, 12.6% a prostaglandin-induced labour and 2.9% an ocytocin-induced labour, and 48.4% had an elective caesarean section. The chance of delivering vaginally was respectively 84.4% for those who had a spontaneous labour, 75.2% for those who were induced using prostaglandin, 82.6% after induction using ocytocin. There were eight uterine ruptures, four after spontaneous labour (1.4%), two after prostaglandin induction (2%) and two at the time of an iterative caesarean section (0.5%). There were no differences between groups, except the risk of haemorrhage (17.4% after spontaneously induced labour, 34.8% after ocytocin, 17.8% after prostaglandin and 44.6% after iterative caesarean section; p<0.005) and the neonatal admissions when analysed by intention to treat only (8.3% after spontaneously induced labour, 9.1% after ocytocin, 12% after prostaglandin and 16.8% after iterative caesarean section; p<0.009). CONCLUSION: Although no increase in maternal or perinatal outcome was observed in relation to prostaglandin-induced labour after caesarean section, this study is too underpowered to exclude an increased risk.

The Impact of Thyroid Disorders on Clinical Pregnancy Outcomes in a Real-World Study Setting.

Background: Subclinical hypothyroidism (SCH) and thyroid autoimmunity (TAI) have been associated with poor clinical pregnancy outcomes. However, these outcomes also depend on a number of demographic and obstetric variables. Therefore, the aim of this study was to investigate the impact of thyroid disorders on these outcomes, after adjustment for associated demographic and obstetrical parameters. Methods: This is cross-sectional study including 1521 pregnant women who underwent work-up and follow-up in the Centre Hospitalier Universitaire (CHU) Saint-Pierre, Brussels, and had ongoing pregnancies. Thyroid function (thyrotropin [TSH], free thyroxine [fT4]) and TAI (thyroid peroxidase antibodies) was determined at median (Q1-Q3) 13 (11-17) weeks. Baseline parameters and the prevalence of poor clinical pregnancy outcomes were compared between controls (no TAI and TSH <2.51 mIU/L) and three study groups (isolated TAI [TSH <2.51 mIU/L], SCH1 [TSH 2.51-3.7 mIU/L], SCH2 [TSH >3.7 mIU/L]). The impact of the different thyroid groups and demographic/obstetric independent variables on six poor clinical pregnancy outcomes (preeclampsia, intrauterine growth restriction [IUGR], preterm birth, neonatal intensive care unit [NICU] admission, low birth weight, and macrosomia) was investigated in a logistic regression model. Treatment with thyroid hormone before and during pregnancy and assisted and multiple pregnancies were exclusion criteria. Results: In total, 79 preeclampsias (5.2%), 40 IUGRs (2.6%), 79 preterm births (5.2%), 10 admissions to NICU (0.66%), 74 low birth weights (4.9%), and 94 babies with macrosomia (6.2%) were documented. TAI was independently associated with NICU admission (adjusted odds ratio [aOR] 16.92 confidence interval [CI 3.36-85.29]; p < 0.001) and TSH, as a continuous variable in the whole range, with preeclampsia (aOR 1.97 [CI 1.18-3.31]; p = 0.010). Trends were present for an association between SCH2 and preeclampsia (aOR 16.73 [CI 1.43-196.42]; p = 0.025), and for SCH1with NICU admission and low birth weight (aOR 19.36 [CI 1.18-316.97]; p = 0.038 and 21.38 [CI 1.29-353.39]; p = 0.032, respectively). Conclusions: Pregnant women with TAI had a significantly higher risk of an admission of the baby to the NICU, and SCH tended to be associated with a higher risk of preeclampsia and low birth weight. Other poor clinical pregnancy outcomes were not associated with thyroid disorders, but with demographic and obstetric parameters.

The human fetal thymus generates invariant effector γδ T cells.

In the mouse thymus, invariant γδ T cells are generated at well-defined times during development and acquire effector functions before exiting the thymus. However, whether such thymic programming and age-dependent generation of invariant γδ T cells occur in humans is not known. Here we found that, unlike postnatal γδ thymocytes, human fetal γδ thymocytes were functionally programmed (e.g., IFNγ, granzymes) and expressed low levels of terminal deoxynucleotidyl transferase (TdT). This low level of TdT resulted in a low number of N nucleotide insertions in the complementarity-determining region-3 (CDR3) of their TCR repertoire, allowing the usage of short homology repeats within the germline-encoded VDJ segments to generate invariant/public cytomegalovirus-reactive CDR3 sequences (TRGV8-TRJP1-CATWDTTGWFKIF, TRDV2-TRDD3-CACDTGGY, and TRDV1-TRDD3-CALGELGD). Furthermore, both the generation of invariant TCRs and the intrathymic acquisition of effector functions were due to an intrinsic property of fetal hematopoietic stem and precursor cells (HSPCs) caused by high expression of the RNA-binding protein Lin28b. In conclusion, our data indicate that the human fetal thymus generates, in an HSPC/Lin28b-dependent manner, invariant γδ T cells with programmed effector functions.