Targeted Deletion of HIF-1α Gene in T Cells Prevents their Inhibition in Hypoxic Inflamed Tissues and Improves Septic Mice Survival

Sepsis patients may die either from an overwhelming systemic immune response and/or from an immunoparalysis-associated lack of anti-bacterial immune defence. We hypothesized that bacterial superantigen-activated T cells may be prevented from contribution into anti-bacterial response due to the inhibition of their effector functions by the hypoxia inducible transcription factor (HIF-1alpha) in inflamed and hypoxic areas.Using the Cre-lox-P-system we generated mice with a T-cell targeted deletion of the HIF-1alpha gene and analysed them in an in vivo model of bacterial sepsis. We show that deletion of the HIF-1alpha gene leads to higher levels of pro-inflammatory cytokines, stronger anti-bacterial effects and much better survival of mice. These effects can be at least partially explained by significantly increased NF-kappaB activation in TCR activated HIF-1 alpha deficient T cells.T cells can be recruited to powerfully contribute to anti-bacterial response if they are relieved from inhibition by HIF-1alpha in inflamed and hypoxic areas. Our experiments uncovered the before unappreciated reserve of anti-bacterial capacity of T cells and suggest novel therapeutic anti-pathogen strategies based on targeted deletion or inhibition of HIF-1 alpha in T cells

Genetic Relationship between Cocirculating Human Enteroviruses Species C

Recombination events between human enteroviruses (HEV) are known to occur frequently and to participate in the evolution of these viruses. In a previous study, we reported the isolation of a panel of viruses belonging to the Human enterovirus species C (HEV-C) that had been cocirculating in a small geographic area of Madagascar in 2002. This panel included type 2 vaccine-derived polioviruses (PV) that had caused several cases of acute flaccid paralysis in humans. Previous partial sequencing of the genome of these HEV-C isolates revealed considerable genetic diversity, mostly due to recombination. In the work presented herein, we carried out a more detailed characterization of the genomes of viruses from this collection. First, we determined the full VP1 sequence of 41 of these isolates of different types. These sequences were compared with those of HEV-C isolates obtained from other countries or in other contexts. The sequences of the Madagascan isolates of a given type formed specific clusters clearly differentiated from those formed by other strains of the same type isolated elsewhere. Second, we sequenced the entire genome of 10 viruses representing most of the lineages present in this panel. All but one of the genomes appeared to be mosaic assemblies of different genomic fragments generated by intra- and intertypic recombination. The location of the breakpoints suggested potential preferred genomic regions for recombination. Our results also suggest that recombination between type HEV-99 and other HEV-C may be quite rare. This first exhaustive genomic analysis of a panel of non-PV HEV-C cocirculating in a small human population highlights the high frequency of inter and intra-typic genetic recombination, constituting a widespread mechanism of genetic plasticity and continually shifting the HEV-C biodiversity

A Retrospective Overview of Enterovirus Infection Diagnosis and Molecular Epidemiology in the Public Hospitals of Marseille, France (1985–2005)

Human enteroviruses (HEV) are frequent human pathogens and, associated in particular with large outbreaks of aseptic meningitis. Here, we have compiled a database of clinical HEV isolates from the Public Hospitals of Marseille, from 1985 to 2005. Amongst 654 isolates that could be characterized by complete sequencing of the VP1 gene, 98% belonged to species HEV-B; the most frequently isolated serotypes were Echovirus E30, E11, E7, E6 and E4. The high incidence of E30 and the recent emergence of E13 are consistent with reports worldwide and peak HEV isolation occurred mostly in the late spring and summer months. The proportion of echoviruses has decreased across the years, while that of coxsackieviruses has increased. Stool (the most frequent sample type) allowed detection of all identified serotypes. MRC5 (Human lung fibroblasts) cell line was the most conducive cell line for HEV isolation (84.9% of 10 most common serotype isolates, 96.3% in association with BGM (Buffalo green monkey kidney cells)). Previous seroneutralization-based serotype identification demonstrated 55.4% accuracy when compared with molecular VP1 analysis. Our analysis of a large number of clinical strains over 20 years reinforced the validity of VP1 serotyping and showed that comparative p-distance scores can be coupled with phylogenetic analysis to provide non-ambiguous serotype identification. Phylogenetic analysis in the VP1, 2C and 3D regions also provided evidence for recombination events amongst clinical isolates. In particular, it identified isolates with dissimilar VP1 but almost identical nonstructural regions

Enhanced Neointima Formation Following Arterial Injury in Immune Deficient Rag-1−/− Mice Is Attenuated by Adoptive Transfer of CD8+ T cells

T cells modulate neointima formation after arterial injury but the specific T cell population that is activated in response to arterial injury remains unknown. The objective of the study was to identify the T cell populations that are activated and modulate neointimal thickening after arterial injury in mice. Arterial injury in wild type C57Bl6 mice resulted in T cell activation characterized by increased CD4+CD44hi and CD8+CD44hi T cells in the lymph nodes and spleens. Splenic CD8+CD25+ T cells and CD8+CD28+ T cells, but not CD4+CD25+ and CD4+CD28+ T cells, were also significantly increased. Adoptive cell transfer of CD4+ or CD8+ T cells from donor CD8−/− or CD4−/− mice, respectively, to immune-deficient Rag-1−/− mice was performed to determine the T cell subtype that inhibits neointima formation after arterial injury. Rag-1−/− mice that received CD8+ T cells had significantly reduced neointima formation compared with Rag-1−/− mice without cell transfer. CD4+ T cell transfer did not reduce neointima formation. CD8+ T cells from CD4−/− mice had cytotoxic activity against syngeneic smooth muscle cells in vitro. The study shows that although both CD8+ T cells and CD4+ T cells are activated in response to arterial injury, adoptive cell transfer identifies CD8+ T cells as the specific and selective cell type involved in inhibiting neointima formation

A hepatitis B virus causes chronic infections in equids worldwide

Preclinical testing of novel therapeutics for chronic hepatitis B (CHB) requires suitable animal models. Equids host homologs of hepatitis C virus (HCV). Because coinfections of hepatitis B virus (HBV) and HCV occur in humans, we screened 2,917 specimens from equids from five continents for HBV. We discovered a distinct HBV species (Equid HBV, EqHBV) in 3.2% of donkeys and zebras by PCR and antibodies against EqHBV in 5.4% of donkeys and zebras. Molecular, histopathological, and biochemical analyses revealed that infection patterns of EqHBV resembled those of HBV in humans, including hepatotropism, moderate liver damage, evolutionary stasis, and potential horizontal virus transmission. Naturally infected donkeys showed chronic infections resembling CHB with high viral loads of up to 2.6 × 109 mean copies per milliliter serum for >6 mo and weak antibody responses. Antibodies against Equid HCV were codetected in 26.5% of donkeys seropositive for EqHBV, corroborating susceptibility to both hepatitis viruses. Deltavirus pseudotypes carrying EqHBV surface proteins were unable to infect human cells via the HBV receptor NTCP (Na+/taurocholate cotransporting polypeptide), suggesting alternative viral entry mechanisms. Both HBV and EqHBV deltavirus pseudotypes infected primary horse hepatocytes in vitro, supporting a broad host range for EqHBV among equids and suggesting that horses might be suitable for EqHBV and HBV infections in vivo. Evolutionary analyses suggested that EqHBV originated in Africa several thousand years ago, commensurate with the domestication of donkeys. In sum, EqHBV naturally infects diverse equids and mimics HBV infection patterns. Equids provide a unique opportunity for preclinical testing of novel therapeutics for CHB and to investigate HBV/ HCV interplay upon coinfection

Beyond a phenomenological description of magnetostriction

We use ultrafast x-ray and electron diffraction to disentangle spin-lattice coupling of granular FePt in the time domain. The reduced dimensionality of single-crystalline FePt nanoparticles leads to strong coupling of magnetic order and a highly anisotropic three-dimensional lattice motion characterized by a- and b-axis expansion and c-axis contraction. The resulting increase of the FePt lattice tetragonality, the key quantity determining the energy barrier between opposite FePt magnetization orientations, persists for tens of picoseconds. These results suggest a novel approach to laser-assisted magnetic switching in future data storage applications.Comment: 12 pages, 4 figure

Mucin impedes cytotoxic effect of 5-FU against growth of human pancreatic cancer cells: overcoming cellular barriers for therapeutic gain

Mucins are high molecular weight glycoproteins expressed on the apical surface of normal epithelial cells. In cancer disease mucins are overexpressed on the entire cellular surface. Overexpression of MUC1 mucin in pancreatic tumours has been correlated with poor patient survival. Current chemotherapeutic approaches such as 5-fluorouracil (5-FU) has produced limited clinical success. In this study we investigated the role of mucin in cytotoxic drug treatment to determine whether the extracellular domain of mucin impedes cytotoxic drug action of 5-FU. Human pancreatic cancer cells revealed high and relatively moderate MUC1 levels for Capan-1 and HPAF-II, respectively, compared to MUC1 negative control (U-87 MG glioblastoma) that showed relatively non-specific anti-MUC1 uptake. Benzyl-α-GalNAc (O-glycosylation inhibitor) was used to reduce mucin on cell surfaces, and neuraminidase was used to hydrolyse sialic acid at the distal end of carbohydrate chains. Benzyl-α-GalNAc had no effect on cell morphology or proliferation at the concentrations employed. The inhibition of O-glycosylation resulted in significant 5-FU antiproliferative activity against Capan-1 and HPAF-II, but not against U-87 MG. However, the exposure of cells to neuraminidase failed to improve the cytotoxic action of 5-FU. Our experimental findings suggest that the overexpression of mucin produced by human pancreatic tumours might limit the effectiveness of chemotherapy

Distinguishing Molecular Features and Clinical Characteristics of a Putative New Rhinovirus Species, Human Rhinovirus C (HRV C)

Background: Human rhinoviruses (HRVs) are the most frequently detected pathogens in acute respiratory tract infections (ARTIs) and yet little is known about the prevalence, recurrence, structure and clinical impact of individual members. During 2007, the complete coding sequences of six previously unknown and highly divergent HRV strains were reported. To catalogue the molecular and clinical features distinguishing the divergent HRV strains, we undertook, for the first time, in silico analyses of all available polyprotein sequences and performed retrospective reviews of the medical records of cases in which variants of the prototype strain, HRV-QPM, had been detected

Characterization of an Outbreak of Hand, Foot, and Mouth Disease in Nanchang, China in 2010

Recent outbreaks of human enterovirus 71 (EV71) infection and EV71-associated hand, foot, and mouth disease (HFMD) in China have affected millions and potentially lead to life-threatening complications in newborns. Furthermore, these outbreaks represent a significant global public health issue in the world. Understanding the epidemiology of HFMD and EV71 infection and their transmission patterns in China is essential for controlling outbreaks. However, no studies on the outbreaks of HFMD and EV71 infection in China during 2010 have been reported. In this report, we carried out an epidemiological analysis to study an outbreak of HFMD and EV71 infection in 2010 in the city of Nanchang in the Jiangxi province of People's Republic of China. From April 7 to May 11, 2010, a total of 109 HFMD cases were reported, and in this report the HFMD cases were studied by both epidemiological and laboratory analyses. The epidemiological study indicates that children aged younger than 8 years old represented more than 90% of the reported cases, with the age group of 1–3 years containing the highest number of cases. Laboratory studies detected a high prevalence of EV71 amongst the cases in our study, suggesting EV71 as a common enterovirus found in HFMD cases in Nanchang. Phylogenetic analysis of the sequence of the VP1 region of four EV71 isolates indicated that the Nanchang strains belong to the C4 subgenotype commonly found in China during outbreaks in 2008 but contain distinct variations from these strains. Our study for the first time characterizes the epidemiology of HFMD and EV71 infection in China in 2010 and furthermore, provides the first direct evidence of the genotype of EV71 circulating in Nanchang, China. Our study should facilitate the development of public health measures for the control and prevention of HFMD and EV71 infection in at-risk individuals in China