French Experience of 2009 A/H1N1v Influenza in Pregnant Women

Background

The first reports on the pandemic influenza 2009 A/H1N1v from the USA, Mexico, and Australia indicated that this disease was associated with a high mortality in pregnant women. The aim of this study was to describe and compare the characteristics of severe critically ill and non-severe pregnant women with 2009 A/H1N1v-related illness in France.

Methodology/Principal Findings

A national registry was created to screen pregnant women with laboratory-confirmed 2009 A/H1N1v influenza. Three hundred and fifteen patients from 46 French hospitals were included: 40 patients were admitted to intensive care units (severe outcomes), 111 were hospitalized in obstetric or medical wards (moderate outcomes), and 164 were outpatients (mild outcomes). The 2009 A/H1N1v influenza illness occurred during all pregnancy trimesters, but most women (54%), notably the severe patients (70%), were in the third trimester. Among the severe patients, twenty (50%) underwent mechanical ventilation, and eleven (28%) were treated with extracorporeal membrane oxygenation. Three women died from A/H1N1v influenza. We found a strong association between the development of a severe outcome and both co-existing illnesses (adjusted odds ratio [OR], 5.1; 95% confidence interval [CI], 2.2–11.8) and a delay in oseltamivir treatment after the onset of symptoms (>3 or 5 days) (adjusted OR, 4.8; 95% CI, 1.9–12.1 and 61.2, 95% CI; 14.4–261.3, respectively). Among the 140 deliveries after 22 weeks of gestation known to date, 19 neonates (14%) were admitted to a neonatal intensive care unit, mainly for preterm delivery, and two neonates died. None of these neonates developed 2009 A/H1N1v infection.

Conclusions

This series confirms the high incidence of complications in pregnant women infected with pandemic A/H1N1v observed in other countries but depicts a lower overall maternal and neonatal mortality and morbidity than indicated in the USA or Australia. Moreover, our data demonstrate the benefit of early oseltamivir treatment in this specific population.     

Independent interaction of the acyltransferase HlyC with two maturation domains of the Escherichia coli toxin HlyA

The apparently unique fatty acylation mechanism that underlies activation (maturation) of Escherichia coli haemolysin and related toxins is further clarified by investigation of the interaction of protoxin with the specific acyltransferase HlyC. Using deleted protoxin variants and protoxin peptides as substrates in an in vitro maturation reaction dependent upon HlyC and acyl-acyl carrier protein, two independent HlyC recognition domains were identified on the 1024-residue protoxin, proA, and they were shown to span the two target lysine residues K₅₆₄ (KI) and K₆₉₀ (KII) that are fatty acylated. Each domain required 15–30 amino acids for basal recognition and 50–80 amino acids for wild-type acylation. The two domains (FAI and FAII) competed with each other in cis and in trans for HlyC. The affinity of FAI for HlyC is approximately four times greater than that of FAII resulting in an overall 80% acylation at KI and 20% acylation at KII in both whole toxin and peptide derivatives. No other proA sequences were required for toxin maturation, and excess Ca²⁺ prevented acylation of both lysines. The lack of primary sequence identity between FAI and FAll domains in proA and among corresponding sites on related protoxins currently precludes an explanation of the basis of HlyC recognition by proA.     

Spectrophotometric assays for measuring redox biomarkers in blood

The assessment of redox status is most frequently performed by measuring redox biomarkers. The spectrophotometer is the most commonly used analytical instrument in biochemistry. There is a huge number of spectrophotometric redox biomarkers and assays, thus distinguishing the most appropriate biomarkers and protocols is overwhelming. The aim of the present review is to propose valid and reliable spectrophotometric assays for measuring redox biomarkers in blood. It is hoped that this work will help researchers to select the most suitable redox biomarkers and assays.     

Expression of the blood-group-related antigens Sialyl Lewis a,Sialyl Lewis x and Lewis y in term placentas of normal,preeclampsia, IUGR- and HELLP-complicated pregnancies

Lewis antigens belong to the blood group of antigens and mediate cellular adhesion through interaction with selectins. Invasive trophoblasts use an array of adhesion molecules to facilitate cell–cell and cell–extracellular matrix interactions. Here, we examined immunohistochemically the expression of Sialyl Lewis a (sLe^a), Sialyl Lewis x (sLe^x) and Lewis y (Le^y) in term placentas obtained from cases of normal, intrauterine growth retardation (IUGR), preeclamptic (PE) and hemolysis, elevated liver enzymes and low platelets syndrome (HELLP) pregnancies. We report the expression of sLe^x in third trimester extravillous trophoblasts (EVT). sLe^x was significantly decreased in IUGR and moderately decreased in PE compared to normal placentas. sLe^x was additionally found in syncytiotrophoblast, without however any significant differences in staining intensity between normal and pathological cases. sLe^a was restricted to amnion epithelium. Finally, Le^y was expressed in cytotrophoblasts and villous endothelial cells. Le^y expression was significantly upregulated in IUGR and HELLP, whereas there was a trend toward increase in PE compared to normal placentas. The present study suggests that downregulation of sLe^x in EVT might be associated with IUGR and PE. Furthermore, Le^y, which was recently described as a potent angiogenic factor, is upregulated in placental villi in conditions associated with placental malperfusion. U. Jeschke and A. Makrigiannakis have contributed equally.     

PARP1 proximity proteomics reveals interaction partners at stressed replication forks

PARP1 mediates poly-ADP-ribosylation of proteins on chromatin in response to different types of DNA lesions. PARP inhibitors are used for the treatment of BRCA1/2-deficient breast, ovarian, and prostate cancer. Loss of DNA replication fork protection is proposed as one mechanism that contributes to the vulnerability of BRCA1/2-deficient cells to PARP inhibitors. However, the mechanisms that regulate PARP1 activity at stressed replication forks remain poorly understood. Here, we performed proximity proteomics of PARP1 and isolation of proteins on stressed replication forks to map putative PARP1 regulators. We identified TPX2 as a direct PARP1-binding protein that regulates the auto-ADP-ribosylation activity of PARP1. TPX2 interacts with DNA damage response proteins and promotes homology-directed repair of DNA double-strand breaks. Moreover, TPX2 mRNA levels are increased in BRCA1/2-mutated breast and prostate cancers, and high TPX2 expression levels correlate with the sensitivity of cancer cells to PARP-trapping inhibitors. We propose that TPX2 confers a mitosis-independent function in the cellular response to replication stress by interacting with PARP1.     

Crystal structure of the BcZBP, a zinc-binding protein from Bacillus cereus

Bacillus cereus is an opportunistic pathogenic bacterium closely related to Bacillus anthracis, the causative agent of anthrax in mammals. A significant portion of the B. cereus chromosomal genes are common to B. anthracis, including genes which in B. anthracis code for putative virulence and surface proteins. B. cereus thus provides a convenient model organism for studying proteins potentially associated with the pathogenicity of the highly infectious B. anthracis. The zinc-binding protein of B. cereus, BcZBP, is encoded from the bc1534 gene which has three homologues to B. anthracis. The protein exhibits deacetylase activity with the N-acetyl moiety of the N-acetylglucosamine and the diacetylchitobiose and triacetylchitotriose. However, neither the specific substrate of the BcZBP nor the biochemical pathway have been conclusively identified. Here, we present the crystal structure of BcZBP at 1.8 A resolution. The N-terminal part of the 234 amino acid protein adopts a Rossmann fold whereas the C-terminal part consists of two beta-strands and two alpha-helices. In the crystal, the protein forms a compact hexamer, in agreement with solution data. A zinc binding site and a potential active site have been identified in each monomer. These sites have extensive similarities to those found in two known zinc-dependent hydrolases with deacetylase activity, MshB and LpxC, despite a low degree of amino acid sequence identity. The functional implications and a possible catalytic mechanism are discussed.     

An EG-VEGF-Dependent Decrease in Homeobox Gene NKX3.1 Contributes to Cytotrophoblast Dysfunction: A Possible Mechanism in Human Fetal Growth Restriction

Idiopathic fetal growth restriction (FGR) is frequently associated with placental insufficiency. Previous reports have provided evidence that endocrine gland–derived vascular endothelial growth factor (EG-VEGF), a placental secreted protein, is expressed during the first trimester of pregnancy, controls both trophoblast proliferation and invasion, and its increased expression is associated with human FGR. In this study, we hypothesize that EG-VEGF-dependent changes in placental homeobox gene expressions contribute to trophoblast dysfunction in idiopathic FGR. The changes in EG-VEGF-dependent homeobox gene expressions were determined using a homeobox gene cDNA array on placental explants of 8–12 wks gestation after stimulation with EG-VEGF in vitro for 24 h. The homeobox gene array identified a greater-than-five-fold increase in HOXA9, HOXC8, HOXC10, HOXD1, HOXD8, HOXD9 and HOXD11, while NKX 3.1 showed a greater-than-two-fold decrease in mRNA expression compared with untreated controls. Homeobox gene NKX3.1 was selected as a candidate because it is a downstream target of EG-VEGF and its expression and functional roles are largely unknown in control and idiopathic FGR-affected placentae. Real-time PCR and immunoblotting showed a significant decrease in NKX3.1 mRNA and protein levels, respectively, in placentae from FGR compared with control pregnancies. Gene inactivation in vitro using short-interference RNA specific for NKX3.1 demonstrated an increase in BeWo cell differentiation and a decrease in HTR-8/SVneo proliferation. We conclude that the decreased expression of homeobox gene NKX3.1 downstream of EG-VEGF may contribute to the trophoblast dysfunction associated with idiopathic FGR pregnancies.