Expression of Cytosolic Peroxiredoxins in Plasmodium Berghei Ookinetes is Regulated by Environmental Factors in the Mosquito bloodmeal

The Plasmodium ookinete develops over several hours in the bloodmeal of its mosquito vector where it is exposed to exogenous stresses, including cytotoxic reactive oxygen species (ROS). How the parasite adapts to these challenging conditions is not well understood. We have systematically investigated the expression of three cytosolic antioxidant proteins, thioredoxin-1 (Trx-1), peroxiredoxin-1 (TPx-1), and 1-Cys peroxiredoxin (1-Cys Prx), in developing ookinetes of the rodent parasite Plasmodium berghei under various growth conditions. Transcriptional profiling showed that tpx-1 and 1-cys prx but not trx-1 are more strongly upregulated in ookinetes developing in the mosquito bloodmeal when compared to ookinetes growing under culture conditions. Confocal immunofluorescence imaging revealed comparable expression patterns on the corresponding proteins. 1-Cys Prx in particular exhibited strong expression in mosquito-derived ookinetes but was not detectable in cultured ookinetes. Furthermore, ookinetes growing in culture upregulated tpx-1 and 1-cys prx when challenged with exogenous ROS in a dose-dependent fashion. This suggests that environmental factors in the mosquito bloodmeal induce upregulation of cytosolic antioxidant proteins in Plasmodium ookinetes. We found that in a parasite line lacking TPx-1 (TPx-1KO), expression of 1-Cys Prx occurred significantly earlier in mosquito-derived TPx-1KO ookinetes when compared to wild type (WT) ookinetes. The protein was also readily detectable in cultured TPx-1KO ookinetes, indicating that 1-Cys Prx at least in part compensates for the loss of TPx-1 in vivo. We hypothesize that this dynamic expression of the cytosolic peroxiredoxins reflects the capacity of the developing Plasmodium ookinete to rapidly adapt to the changing conditions in the mosquito bloodmeal. This would significantly increase its chances of survival, maturation and subsequent escape. Our results also emphasize that environmental conditions must be taken into account when investigating Plasmodium-mosquito interactions

Influence of the gut microbiome on IgE and non-IgE-mediated food allergies

Congress of the European-Academy-of-Allergy-and-Clinical-Immunology (EAACI) -- MAY 26-30, 2018 -- Munich, GERMANYWOS: 000441690400204Background: The prevalence of food allergy (FA) in children has been increasing in last decade. Recent studies show changes in gut microbiome with FA. However, whether gut microbiome may differ between IgE and non‐IgE‐mediated FA is not defined. The aim of this study is to examine the intestinal microbiome composition in infants with IgE and non‐IgE‐mediated FA and healthy infants. Method: Infants younger than 1‐year‐old, breastfed and diagnosed with FA by a physician were included in the study. DNA was isolated from stool samples of infants with non‐IgE‐mediated FA (n = 25) and IgE‐mediated FA (n = 11) and healthy infants (n = 7). Whole genome shotgun sequencing was applied to identify the composition of microbial DNA (an average depth of 3.1 ± 0.8 million paired end reads and 0.9 ± 0.2 gigabase pairs). Results: There were compositional differences among 3 different groups. Shannon index was significantly higher in IgE‐mediated FA compared to non‐IgE‐mediated FA group (Kruskal‐Wallis test, P = 0.034). Even though β‐diversity was similar, the Sparse Partial Least Square Discriminant Analysis (sPLS‐DA) demonstrated that there were taxa‐level differences among three groups. In species level, Veillonella parvula was in a significantly higher density in healthy infants compared to IgE and non‐IgE‐mediated FA groups. Rahnella aquatilis and Lactobacillus salivarius were significantly lower and Treponema succinifaciens significantly higher in IgE‐mediated FA group compared to other groups. Additionally, Prevotella sp. oral taxon 299 was significantly lower in non‐IgE‐mediated FA group compared to others. Prevotella sp oral taxon 299 was related to mucus in stool whereas urticaria related species were Olsenall uli, Bactreoides thetaiotaomicron, Klebsiella variiocola, Rahnella aquatilis, Treponema succinfaciens, Ethanoligenens harbinenese. Conclusion: Analysis of microbiome differences in FA patients may aid in the understanding of the disease process. The present data suggest that there are compositional variations mostly in species‐ level among infants with FA and healthy ones. Our results suggest that the gut microbiome has a stronger relationship to IgE‐mediated than non‐IgE‐mediated FA. Further functional analysis of the microbiome may help better understand the changes seen in the gut microbiome in FAs and improve our knowledge in the disease etiopathology.European Academy of Allergy and Clinical Immunolog

Bone Marrow Support of the Heart in Pressure Overload Is Lost with Aging

Exogenous stem cell delivery is under investigation to prevent and treat cardiac dysfunction. It is less studied as to the extent endogenous bone marrow derived stem cells contribute to cardiac homeostais in response to stress and the affects of aging on this stress response.To determine the role of bone marrow (BM) derived stem cells on cardiac homeostasis in response to pressure overload (PO) and how this response is altered by aging.Young (8 weeks) and old (>40 weeks) C57/b6 mice underwent homo- and heterochronic BM transplantation prior to transverse aortic constriction (TAC). We found that older BM is associated with decreased cardiac function following TAC. This decreased function is associated with decrease in BM cell engraftment, increased myocyte apoptosis, decreased myocyte hypertrophy, increased myocardial fibrosis and decreased cardiac function. Additionally, there is a decrease in activation of resident cells within the heart in response to PO in old mice. Interestingly, these effects are not due to alterations in vascular density or inflammation in response to PO or differences in ex vivo stem cell migration between young and old mice.BM derived stem cells are activated in response to cardiac PO, and the recruitment of BM derived cells are involved in cardiac myocyte hypertrophy and maintenance of function in response to PO which is lost with aging

Early Origins of Childhood Asthma: Role of Perinatal Microbial Exposure and Innate Immunity

Asthma—defined by reversible expiratory airflow obstruction-- is the most common chronic disease of childhood in the United States. While many triggers (e.g. bacteria, viruses, allergens, and pollution) have been identified as causative agents of asthma, there is no single etiology that drives reversible obstruction children. The pathogenesis of childhood asthma likely stems from an individual x environment interaction that is highly complex. The focus of the studies of the Finn-Perkins lab described here was to identify microbial exposures and immunological differences at birth that are predictive of asthma development, asthmatic response to triggers, and severity of asthmatic symptoms. Although there is no known single etiologic agent, children with asthma have demonstrable skewing of T-cell responses toward Th2 or “allergic” processes. Using an unbiased approach, we assessed relationships between perinatal microbial exposure and Th2 responses to common air-borne allergens that are known asthma triggers. We identified a specific phyla of Gram negative organisms, Proteobacteria, with negative associations with Th2 responses. Further, increased abundance of Proteobacteria was significantly associated with reduced risk of wheezing childhood. Together, this is suggestive of a protective role of early exposure to Proteobacteria. While Th2 responses are a hallmark of childhood asthma, it is not clear what predisposes to this immunologic skewing later in childhood. There are many risk factors for childhood asthma that have been identified, and many of these are discernable at birth (e.g. sex, mode of delivery, gestational age…). We demonstrated that the pre/perinatal risk factors have additive effects and in using an unbiased approach, we were able to identify a transcriptional signature associated with pre/perinatal risk stratification. xiv Additionally, we determined that umbilical cord serum PGLYRP-1 concentrations were predictive of this transcriptional signature, current asthma at 7 years old, and FEV1/FVC at 12 years old. The concentration of PGLYRP-1 was associated with perinatal exposure to Proteobacteria and several Proteobacteria genera. Collectively, this suggests that early exposure to Proteobacteria enhances innate immunity and, through enhanced innate immunity, may protect against future development of asthma. Additionally, these findings demonstrate that accurate prediction of asthma risk may be capable at birth using a serological marker, PGLYRP-1

Bronchiolitis obliterans syndrome susceptibility and the pulmonary microbiome

BackgroundLung transplantation outcomes remain complicated by bronchiolitis obliterans syndrome (BOS), a major cause of mortality and retransplantation for patients. A variety of factors linking inflammation and BOS have emerged, meriting further exploration of the microbiome as a source of inflammation. In this analysis, we determined features of the pulmonary microbiome associated with BOS susceptibility.MethodsBronchoalveolar lavage (BAL) samples were collected from 25 patients during standard of care bronchoscopies before BOS onset. Microbial DNA was isolated from BAL fluid and prepared for metagenomics shotgun sequencing. Patient microbiomes were phenotyped using k-means clustering and compared to determine effects on BOS-free survival.ResultsClustering identified 3 microbiome phenotypes: Actinobacteria dominant (AD), mixed, and Proteobacteria dominant. AD microbiomes, distinguished by enrichment with Gram-positive organisms, conferred reduced odds and risks for patients to develop acute rejection and BOS compared with non-AD microbiomes. These findings were independent of treatment models. Microbiome findings were correlated with BAL cell counts and polymorphonuclear cell percentages.ConclusionsIn some populations, features of the microbiome may be used to assess BOS susceptibility. Namely, a Gram-positive enriched pulmonary microbiome may predict resilience to BOS

Challenge of ookinete cultures with increasing concentrations of the ROS producing agent paraquat (PQ).

<p>RT-qPCR data showing dose-response modulation of target gene expression in ookinete cultures in the presence of increasing concentrations of the superoxide-producing compound Paraquat (PQ, Viologen, Aldrich). Increasing concentrations of PQ were added to 12-hours <i>P. berghei</i> ookinete cultures as indicated. Shown are the ratios of normalized relative transcript quantities (RQ) of treated vs. non-treated samples (non-treated RQ = 1, represented by the dashed line). All data were normalized against the expression of 18 s rRNA A-type <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003136#ppat.1003136-Yano1" target="_blank">[29]</a>, <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003136#ppat.1003136-Thompson1" target="_blank">[34]</a>. (*) indicates statistical significance (p<0.1). Shown are mean values of 3 independent experiments. Error bars indicate STDEV.</p

Candidate genes of the cytosolic thioredoxin system of <i>P. berghei</i>.

<p>Candidate genes of the cytosolic thioredoxin system of <i>P. berghei</i>.</p

Expression of the Trx-1, TPx-1 and 1-Cys Prx in developing ookinetes from culture or from mosquito bloodmeal.

<p>Samples were isolated from ookinete cultures and blood fed mosquitoes at indicated time points and prepared as described in material and methods. Fixed samples were probed with <b>A</b>) anti-PbTrx-1, <b>B</b>) anti-Pf TPx-1 or <b>C</b>) anti-PbTPx-1. Primary antibodies were probed with secondary antibody coupled to AF 488 (Molecular Probes). Samples were counterstained with the nuclear dye TO-PRO-3 (Life technologies). The source of the ookinetes from either ookinete cultures or bloodfed mosquito midguts is indicated. Images are merged and overlaid onto the respective DIC image. White arrows indicate accumulation of Trx-1, TPx-1 or 1-Cys Prx at the apical ends of developing ookinetes. Scale bar = 5 µM. Quantitative <i>Relative Fluorescence Analysis</i>: Shown is the median boxed by the first and third quartiles with minimum and maximum values displayed as whiskers. Mann-Whitney U-Test was performed with samples of culture-derived ookinetes compared to mosquito-derived ookinetes (p = 0.4551 for Trx-1; p = 0.1061 for TPx-1; p = 0.0413 for 1-Cys Prx). Below each graph are representative images from IFA-epifluorescence experiments.</p