Impact of HIV on cell survival and antiviral activity of plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) are important mediators of innate immunity that act mainly through secretion of interferon (IFN)-alpha. Previous studies have found that these cells can suppress HIV in vitro; additionally, pDCs have been shown to be severely reduced in the peripheral blood of HIV-infected individuals. In the present study, we sought to determine the ability of pDCs to directly suppress viral replication ex vivo and to delineate the potential mechanisms whereby pDCs are depleted in HIV-infected individuals. We demonstrate that activated pDCs strongly suppress HIV replication in autologous CD4(+) T cells via a mechanism involving IFN-alpha as well as other antiviral factors. Of note, unstimulated pDCs from infected individuals who maintain low levels of plasma viremia without antiretroviral therapy were able to suppress HIV ex vivo via a mechanism requiring cell-to-cell contact. Our data also demonstrate that death of pDCs by both apoptosis and necrosis is induced by fusion of HIV with pDCs. Taken together, our data suggest that pDCs play an important role in the control of HIV replication and that high levels of viral replication in vivo are associated with pDC cell death via apoptosis and necrosis. Elucidation of the mechanism by which pDCs suppress HIV replication in vivo may have clinically relevant implications for future therapeutic strategies.     

Hospitalisation with infection, asthma and allergy in Kawasaki disease patients and their families: genealogical analysis using linked population data

Background

Kawasaki disease results from an abnormal immunological response to one or more infectious triggers. We hypothesised that heritable differences in immune responses in Kawasaki disease-affected children and their families would result in different epidemiological patterns of other immune-related conditions. We investigated whether hospitalisation for infection and asthma/allergy were different in Kawasaki disease-affected children and their relatives.

Methods/Major Findings

We used Western Australian population-linked health data from live births (1970–2006) to compare patterns of hospital admissions in Kawasaki disease cases, age- and sex-matched controls, and their relatives. There were 295 Kawasaki disease cases and 598 age- and sex-matched controls, with 1,636 and 3,780 relatives, respectively. Compared to controls, cases were more likely to have been admitted at least once with an infection (cases, 150 admissions (50.8%) vs controls, 210 admissions (35.1%); odds ratio (OR) = 1.9, 95% confidence interval (CI) 1.4–2.6, P = 7.2×10⁻⁶), and with asthma/allergy (cases, 49 admissions (16.6%) vs controls, 42 admissions (7.0%); OR = 2.6, 95% CI 1.7–4.2, P = 1.3×10⁻⁵). Cases also had more admissions per person with infection (cases, median 2 admissions, 95% CI 1–5, vs controls, median 1 admission, 95% CI 1–4, P = 1.09×10⁻⁵). The risk of admission with infection was higher in the first degree relatives of Kawasaki disease cases compared to those of controls, but the differences were not significant.

Conclusion

Differences in the immune phenotype of children who develop Kawasaki disease may influence the severity of other immune-related conditions, with some similar patterns observed in relatives. These data suggest the influence of shared heritable factors in these families.     

Bladder cancer SNP panel predicts susceptibility and survival

Bladder cancer is the fourth most common malignancy in men and the eighth most common in women in western countries. Single nucleotide polymorphisms (SNPs) in genes that regulate telomere maintenance, mitosis, inflammation, and apoptosis have not been assessed extensively for this disease. Using a population-based study with 832 bladder cancer cases and 1,191 controls, we assessed genetic variation in relation to cancer susceptibility or survival. Findings included an increased risk associated with variants in the methyl-metabolism gene, MTHFD2 (OR 1.7 95% CI 1.3–2.3), the telomerase TEP1 (OR 1.8 95% CI 1.2–2.6) and decreased risk associated with the inflammatory response gene variant IL8RB (OR 0.6 95% CI 0.5–0.9) compared to wild-type. Shorter survival was associated with apoptotic gene variants, including CASP9 (HR 1.8 95% CI 1.1–3.0). Variants in the detoxification gene EPHX1 experienced longer survival (HR 0.4 (95% CI 0.2–0.8). These genes can now be assessed in multiple study populations to identify and validate SNPs appropriate for clinical use.     

Comparison and transfer testing of multiplex ligation detection methods for GM plants

Background  

With the increasing number of GMOs on the global market the maintenance of European GMO regulations is becoming more complex. For the analysis of a single food or feed sample it is necessary to assess the sample for the presence of many GMO-targets simultaneously at a sensitive level. Several methods have been published regarding DNA-based multidetection. Multiplex ligation detection methods have been described that use the same basic approach: i) hybridisation and ligation of specific probes, ii) amplification of the ligated probes and iii) detection and identification of the amplified products. Despite they all have this same basis, the published ligation methods differ radically. The present study investigated with real-time PCR whether these different ligation methods have any influence on the performance of the probes. Sensitivity and the specificity of the padlock probes (PLPs) with the ligation protocol with the best performance were also tested and the selected method was initially validated in a laboratory exchange study.     

A human PrM antibody that recognizes a novel cryptic epitope on dengue E glycoprotein

Dengue virus (DENV) is a major mosquito-borne pathogen infecting up to 100 million people each year; so far no effective treatment or vaccines are available. Recently, highly cross-reactive and infection-enhancing pre-membrane (prM)-specific antibodies were found to dominate the anti-DENV immune response in humans, raising concern over vaccine candidates that contain native dengue prM sequences. In this study, we have isolated a broadly cross-reactive prM-specific antibody, D29, during a screen with a non-immunized human Fab-phage library against the four serotypes of DENV. The antibody is capable of restoring the infectivity of virtually non-infectious immature DENV (imDENV) in FcγR-bearing K562 cells. Remarkably, D29 also cross-reacted with a cryptic epitope on the envelope (E) protein located to the DI/DII junction as evidenced by site-directed mutagenesis. This cryptic epitope, while inaccessible to antibody binding in a native virus particle, may become exposed if E is not properly folded. These findings suggest that generation of anti-prM antibodies that enhance DENV infection may not be completely avoided even with immunization strategies employing E protein alone or subunits of E proteins.     

SLC39A2 and FSIP1 polymorphisms as potential modifiers of arsenic-related bladder cancer

Arsenic is a carcinogen that contaminates drinking water worldwide. Accumulating evidence suggests that both exposure and genetic factors may influence susceptibility to arsenic-induced malignancies. We sought to identify novel susceptibility loci for arsenic-related bladder cancer in a US population with low to moderate drinking water levels of arsenic. We first screened a subset of bladder cancer cases using a panel of approximately 10,000 non-synonymous single nucleotide polymorphisms (SNPs). Top ranking hits on the SNP array then were considered for further analysis in our population-based case-control study (n = 832 cases and 1,191 controls). SNPs in the fibrous sheath interacting protein 1 (FSIP1) gene (rs10152640) and the solute carrier family 39, member 2 (SLC39A2) in the ZIP gene family of metal transporters (rs2234636) were detected as potential hits in the initial scan and validated in the full case-control study. The adjusted odds ratio (OR) for the FSIP1 polymorphism was 2.57 [95% confidence interval (CI) 1.13, 5.85] for heterozygote variants (AG) and 12.20 (95% CI 2.51, 59.30) for homozygote variants (GG) compared to homozygote wild types (AA) in the high arsenic group (greater than the 90th percentile), and unrelated in the low arsenic group (equal to or below the 90th percentile) (P for interaction = 0.002). For the SLC39A2 polymorphism, the adjusted ORs were 2.96 (95% CI 1.23, 7.15) and 2.91 (95% CI 1.00, 8.52) for heterozygote (TC) and homozygote (CC) variants compared to homozygote wild types (TT), respectively, and close to one in the low arsenic group (P for interaction = 0.03). Our findings suggest novel variants that may influence risk of arsenic-associated bladder cancer and those who may be at greatest risk from this widespread exposure.     

Genetic Population Structure Analysis in New Hampshire Reveals Eastern European Ancestry

Genetic structure due to ancestry has been well documented among many divergent human populations. However, the ability to associate ancestry with genetic substructure without using supervised clustering has not been explored in more presumably homogeneous and admixed US populations. The goal of this study was to determine if genetic structure could be detected in a United States population from a single state where the individuals have mixed European ancestry. Using Bayesian clustering with a set of 960 single nucleotide polymorphisms (SNPs) we found evidence of population stratification in 864 individuals from New Hampshire that can be used to differentiate the population into six distinct genetic subgroups. We then correlated self-reported ancestry of the individuals with the Bayesian clustering results. Finnish and Russian/Polish/Lithuanian ancestries were most notably found to be associated with genetic substructure. The ancestral results were further explained and substantiated using New Hampshire census data from 1870 to 1930 when the largest waves of European immigrants came to the area. We also discerned distinct patterns of linkage disequilibrium (LD) between the genetic groups in the growth hormone receptor gene (GHR). To our knowledge, this is the first time such an investigation has uncovered a strong link between genetic structure and ancestry in what would otherwise be considered a homogenous US population.     

A phylogenetic hypothesis for the Aizoaceae (Caryophyllales) based on four plastid DNA regions

The Aizoaceae is the largest family of leaf succulent plants, and most of its species are endemic to southern Africa. To evaluate subfamilial, generic, and tribal relationships, we produced two plastid DNA data sets for 91 species of Aizoaceae and four outgroups: rps16 intron and the trnL-F gene region (both the trnL intron and the trnL-F intergenic spacer). In addition, we generated two further plastid data sets for 56 taxa restricted to members of the Ruschioideae using the atpB-rbcL and the psbA-trnH intergenic spacers. In the combined tree of the rps16 intron and trnL-F gene region, three of the currently recognized subfamilies (Sesuvioideae, Mesembryanthemoideae, and Ruschioideae) are each strongly supported monophyletic groups. The subfamily Tetragonioideae is polyphyletic, with Tribulocarpus as sister to the Sesuvioideae and Tetragonia embedded in the Aizooideae. Our study showed that the group consisting of the Sesuvioideae, Aizooideae, and Tetragonioideae does not form a monophyletic entity. Therefore, it cannot be recognized as a separate family in order to accommodate the frequently used concept of the Mesembryanthemaceae or "Mesembryanthema," in which the subfamilies Mesembryanthemoideae and Ruschioideae are included. We also found that several genera within the Mesembryanthemoideae (Mesembryanthemum, Phyllobolus) are not monophyletic. Within the Ruschioideae, our study retrieved four major clades. However, even in the combined analysis of all four plastid gene regions, relationships within the largest of these four clades remain unresolved. The few nucleotide substitutions that exist among taxa of this clade point to a rapid and recent diversification within the arid winter rainfall area of southern Africa. We propose a revised classification for the Aizoaceae.     

Strategies for surviving high concentrations of environmental ammonia in the swamp eel Monopterus albus

The swamp eel Monopterus albus lives in muddy ponds, swamps, canals, and rice fields in the tropics. It encounters high concentrations of environmental ammonia (HEA) during dry seasons or during agricultural fertilization in rice fields. This study aimed at determining the tolerance of M. albus to environmental ammonia and at elucidating the strategies that it adopts to defend against ammonia toxicity in HEA. In the laboratory, M. albus exhibited very high environmental ammonia tolerance; the 48-, 72-, and 96-h median lethal concentrations of total ammonia at pH 7.0 and 28 degrees C were 209.9, 198.7, and 193.2 mM, respectively. It was apparently incapable of actively excreting ammonia against a concentration gradient. In addition, it did not detoxify ammonia to urea, the excretion of which would lead to a loss of nitrogen and carbon, during ammonia loading. The high tolerance of M. albus to HEA was attributable partially to its exceptionally high tolerance to ammonia at the cellular and subcellular levels. During the 144 h of exposure to 75 mM NH(4)Cl at pH 7.0, the ammonia contents in the muscle, liver, brain, and gut of M. albus reached 11.49, 15.18, 6.48, and 7.51 mu mol g(-1), respectively. Such a capability allowed the accumulation of high concentrations of ammonia in the plasma (3.54 mu mol mL(-1)) of M. albus exposed to HEA, which would reduce the net influx of exogenous ammonia. Subsequent to the buildup of internal ammonia levels, M. albus detoxified ammonia produced endogenously to glutamine. The glutamine contents in the muscle and liver reached 10.84 and 17.06 mu mol g(-1), respectively, after 144 h of exposure to HEA, which happened to be the highest known for fish. Unlike urea, the storage of glutamine in the muscle during ammonia loading allowed its usage for anabolic purposes when the adverse environmental condition subsides. Glutamine synthetase activity increased significantly in the liver and gut (2.8- and 1.5-fold, respectively) of specimens exposed to HEA for 144 h. These results suggest that the liver was the main site of ammonia detoxification and the gut was more than a digestive/absorptive organ in M. albus. Monopterus albus did not undergo a reduction in amino acid catabolism during the first 24 h of ammonia exposure. However, assuming a total inhibition of excretion of endogenous ammonia, there was a deficit of -312 mu mol N between the reduction in nitrogenous excretion (3,360 mu mol N) and the retention of nitrogen (3,048 mu mol N) after 72 h of aerial exposure. The deficit became much greater after 144 h, reaching a value of -3,243 mu mol N. These results suggest that endogenous ammonia production in M. albus was suppressed in order to prevent the newly established internal steady state concentration of ammonia from rising to an intolerable level after an extended period of exposure to HEA.