Abstract
Background
Proton pump inhibitors (PPIs) are associated with acute tubulointerstitial nephritis and there are reports associating their use with the development of chronic kidney disease ...(CKD).
Aim
To determine if PPI use is associated with major adverse renal events (MARE) in patients with CKD.
Design
Observational cohort study comprising patients with CKD attending secondary care renal clinics from 1 January 2006 until 31 December 2016.
Methods
We collated baseline clinical, socio-demographic and biochemical data at start of PPI (PPI group) or study inception (control group). MARE was considered a composite of doubling of creatinine or end-stage renal disease. Association between PPI exposure and progression to MARE was assessed by cause-specific hazards competing risk survival analysis.
Results
There were 3824 patients with CKD included in the analyses of whom 1195 were prescribed a PPI. The PPI group was younger (64.8 vs. 67.0 years, P < 0.001), with lower estimated glomerular filtration rate (eGFR) (30 vs. 35 ml/min, P < 0.001) and more proteinuria (64 vs. 48 mg/mmol, P < 0.001). PPI use was associated with progression to MARE on multivariable adjustment (hazard ratio 1.13 95% confidence interval 1.02–1.25, P = 0.021). Other factors significantly associated with progression to MARE were higher systolic blood pressure, lower eGFR, greater proteinuria, congestive cardiac failure and diabetes. Hypomagnesaemia was more common in the PPI group (39.5 vs. 18.9%, P < 0.001).
Conclusion
PPI use was associated with progression to MARE, but not death in patients with CKD after adjusting for factors known to predict declining renal function, including lower eGFR, proteinuria and comorbidities. A prospective cohort study is required to validate these findings.
can cause the disease coccidiosis in chickens. The direct and often detrimental impact of this parasite on chicken health, welfare, and productivity is well recognized; however, less is known about ...the secondary effects that infection may have on other gut pathogens.
is the leading cause of human bacterial foodborne disease in many countries and has been demonstrated to exert negative effects on poultry welfare and production in some broiler lines. Previous studies have shown that concurrent
infection can influence the colonization and replication of bacteria, such as
and
serovar Typhimurium. Through a series of
coinfection experiments, this study evaluated the impact that
infection had on
colonization of chickens, including the influence of variations in parasite dose and sampling time after bacterial challenge. Coinfection with
resulted in a significant increase in
colonization in the cecum in a parasite dose-dependent manner but a significant decrease in
colonization in the spleen and liver of chickens. The results were reproducible at 3 and 10 days after bacterial infection. This work highlights that
not only has a direct impact on the health and well-being of chickens but can have secondary effects on important zoonotic pathogens.
Abstract
Background
Worldwide, an estimated 70.7 billion broilers were produced in 2020. With the reduction in use of prophylactic antibiotics as a result of consumer pressure and regulatory ...oversight alternative approaches, such as vaccination, are required to control bacterial infections. A potential way to produce a multivalent vaccine is via the generation of a glycoconjugate vaccine which consists of an antigenic protein covalently linked to an immunogenic carbohydrate. Protein-glycan coupling technology (PGCT) is an approach to generate glycoconjugates using enzymes that can couple proteins and glycan when produced in bacterial cells. Previous studies have used PGCT to generate a live-attenuated avian pathogenic
Escherichia coli
(APEC) strain capable of
N
-glycosylation of target proteins using a chromosomally integrated
Campylobacter jejuni pgl
locus. However, this proved ineffective against
C. jejuni
challenge.
Results
In this study we demonstrate the lack of surface exposure of glycosylated protein in APEC strain χ7122 carrying the
pgl
locus
.
Furthermore, we hypothesise that this may be due to the complex cell-surface architecture of
E. coli.
To this end, we removed the lipopolysaccharide O-antigen of APEC χ7122
pgl
+
via deletion of the
wecA
gene and demonstrate increased surface exposure of glycosylated antigens (NetB and FlpA) in this strain. We hypothesise that increasing the surface expression of the glycosylated protein would increase the chance of host immune cells being exposed to the glycoconjugate, and therefore the generation of an efficacious immune response would be more likely.
Conclusions
Our results demonstrate an increase in cell surface exposure and therefore accessibility of glycosylated antigens upon removal of lipopolysaccharide antigen from the APEC cell surface.
Summary
Burkholderia pseudomallei is a Gram‐negative facultative intracellular pathogen that enters and escapes from eukaryotic cells using the power of actin polymerization. We have identified a ...bacterial protein (BimA) that is required for the ability of B. pseudomallei to induce the formation of actin tails. BimA contains proline‐rich motifs and WH2‐like domains and shares limited homology at the C‐terminus with the Yersinia autosecreted adhesin YadA. BimA is located at the pole of the bacterial cell at which actin polymerization occurs and mutation of bimA abolished actin‐based motility of the pathogen in J774.2 cells. Transient expression of BimA in HeLa cells resulted in F‐actin clustering reminiscent of that seen on WASP overexpression. Antibody‐mediated clustering of a CD32 chimera in which the cytoplasmic domain was replaced with BimA resulted in localization of the chimera to the tips of F‐actin enriched membrane protrusions. We report that purified truncated BimA protein binds monomeric actin in a concentration‐dependent manner in cosedimentation assays and that BimA stimulates actin polymerization in vitro in a manner independent of the cellular Arp2/3 complex.
Salmonella enterica subspecies enterica is an animal and zoonotic pathogen of global importance. Cattle are a significant reservoir of human non-typhoidal salmonellosis and can suffer enteric and ...systemic disease owing to the ability of Salmonella to survive within the bovine lymphatic system and intestines. Contamination of food can occur due to the incorporation of contaminated peripheral lymph nodes or by direct contamination of carcasses with gut contents. It is essential to understand the mechanisms used by Salmonella to enter and persist within the bovine lymphatic system and how they differ from those required for intestinal colonization to minimize zoonotic infections.
Transposon-directed insertion site sequencing (TraDIS) was applied to pools of mutants recovered from mesenteric lymph nodes (MLNs) draining the distal ileum of calves after oral inoculation with a library of 8550 random S. Typhimurium mini-Tn5Km2 mutants in pools of 475 mutants per calf. A total of 8315 mutants representing 2852 different genes were detected in MLNs and their in vivo fitness was calculated. Using the same improved algorithm for analysis of transposon-flanking sequences, the identity and phenotype of mutants recovered from the distal ileal mucosa of the same calves was also defined, enabling comparison with previously published data and of mutant phenotypes across the tissues. Phenotypes observed for the majority of mutants were highly significantly correlated in the two tissues. However, 32 genes were identified in which transposon insertions consistently resulted in differential fitness in the ileal wall and MLNs, suggesting niche-specific roles for these genes in pathogenesis. Defined null mutations affecting ptsN and spvC were confirmed to result in tissue-specific phenotypes in calves, thus validating the TraDIS dataset.
This validation of the role of thousands of Salmonella genes and identification of genes with niche-specific roles in a key target species will inform the design of control strategies for bovine salmonellosis and zoonotic infections, for which efficacious and cross-protective vaccines are currently lacking.
Conventional dendritic cells (cDCs) are antigen-presenting cells (APCs) that play a central role in linking innate and adaptive immunity. cDCs have been well described in a number of different ...mammalian species, but remain poorly characterised in the chicken. In this study, we use previously described chicken cDC specific reagents, a novel gene-edited chicken line and single-cell RNA sequencing (scRNAseq) to characterise chicken splenic cDCs. In contrast to mammals, scRNAseq analysis indicates that the chicken spleen contains a single, chemokine receptor XCR1 expressing, cDC subset. By sexual maturity the XCR1
cDC population is the most abundant mononuclear phagocyte cell subset in the chicken spleen. scRNAseq analysis revealed substantial heterogeneity within the chicken splenic XCR1
cDC population. Immature MHC class II (MHCII)
XCR1
cDCs expressed a range of viral resistance genes. Maturation to MHCII
XCR1
cDCs was associated with reduced expression of anti-viral gene expression and increased expression of genes related to antigen presentation via the MHCII and cross-presentation pathways. To visualise and transiently ablate chicken XCR1
cDCs
, we generated
-iCaspase9-RFP chickens using a CRISPR-Cas9 knockin transgenesis approach to precisely edit the
locus, replacing the XCR1 coding region with genes for a fluorescent protein (TagRFP), and inducible Caspase 9. After inducible ablation, the chicken spleen is initially repopulated by immature CD1.1
XCR1
cDCs. XCR1
cDCs are abundant in the splenic red pulp, in close association with CD8
T-cells. Knockout of XCR1 prevented this clustering of cDCs with CD8
T-cells. Taken together these data indicate a conserved role for chicken and mammalian XCR1
cDCs in driving CD8
T-cells responses.
, the causative agent of melioidosis, can survive and replicate in macrophages. Little is known about
genes that are induced during macrophage infection. We constructed a
K96243 promoter trap library ...with genomic DNA fragments fused to the 5' end of a plasmid-borne gene encoding enhanced green fluorescent protein (eGFP). Microarray analysis showed that the library spanned 88% of the
genome. The recombinant plasmids were introduced into
E264, and promoter fusions active during
culture were removed. J774A.1 murine macrophages were infected with the promoter trap library, and J774A.1 cells containing fluorescent bacteria carrying plasmids with active promoters were isolated using flow cytometric-based cell sorting. Candidate macrophage-induced
genes were identified from the location of the insertions containing an active promoter activity. A proportion of the 138 genes identified in this way have been previously reported to be involved in metabolism and transport, virulence, or adaptation. Novel macrophage-induced
genes were also identified. Quantitative reverse-transcription PCR analysis of 13 selected genes confirmed gene induction during macrophage infection. Deletion mutants of two macrophage-induced genes from this study were attenuated in
larvae, suggesting roles in virulence.
genes activated during macrophage infection may contribute to intracellular life and pathogenesis and merit further investigation toward control strategies for melioidosis.
Conventional dendritic cells (cDC) are bone marrow‐derived immune cells that play a central role in linking innate and adaptive immunity. cDCs efficiently uptake, process and present antigen to naïve ...T cells, driving clonal expansion of antigen‐specific T‐cell responses. In chicken, vital reagents are lacking for the efficient and precise identification of cDCs. In this study, we have developed several novel reagents for the identification and characterization of chicken cDCs. Chicken FLT3 cDNA was cloned and a monoclonal antibody to cell surface FLT3 was generated. This antibody identified a distinct FLT3HI splenic subset which lack expression of signature markers for B cells, T cells or monocyte/macrophages. By combining anti‐FLT3 and CSF1R‐eGFP transgenic expression, three major populations within the mononuclear phagocyte system were identified in the spleen. The cDC1 subset of mammalian cDCs express the chemokine receptor XCR1. To characterize chicken cDCs, a synthetic chicken chemokine (C motif) ligand (XCL1) peptide conjugated to Alexa Fluor 647 was developed (XCL1AF647). Flow cytometry staining of XCL1AF647 on splenocytes showed that all chicken FLT3HI cells exclusively express XCR1, supporting the hypothesis that this population comprises bona fide chicken cDCs. Further analysis revealed that chicken cDCs expressed CSF1R but lacked the expression of CSF2R. Collectively, the cell surface phenotypes of chicken cDCs were partially conserved with mammalian XCR1+ cDC1, with distinct differences in CSF1R and CSF2R expression compared with mammalian orthologues. These original reagents allow the efficient identification of chicken cDCs to investigate their important roles in the chicken immunity and diseases.
We have developed tools to specifically identify chicken conventional dendritic cells (cDCs). Chicken cDCs are express high levels of FLT3 and XCR1. While the resemble the mammalian cDC1 subset, significant differences exist.
The domestic chicken (Gallus gallus) is widely used as a model in developmental biology and is also an important livestock species. We describe a novel approach to data integration to generate an ...mRNA expression atlas for the chicken spanning major tissue types and developmental stages, using a diverse range of publicly-archived RNA-seq datasets and new data derived from immune cells and tissues.
Randomly down-sampling RNA-seq datasets to a common depth and quantifying expression against a reference transcriptome using the mRNA quantitation tool Kallisto ensured that disparate datasets explored comparable transcriptomic space. The network analysis tool Graphia was used to extract clusters of co-expressed genes from the resulting expression atlas, many of which were tissue or cell-type restricted, contained transcription factors that have previously been implicated in their regulation, or were otherwise associated with biological processes, such as the cell cycle. The atlas provides a resource for the functional annotation of genes that currently have only a locus ID. We cross-referenced the RNA-seq atlas to a publicly available embryonic Cap Analysis of Gene Expression (CAGE) dataset to infer the developmental time course of organ systems, and to identify a signature of the expansion of tissue macrophage populations during development.
Expression profiles obtained from public RNA-seq datasets - despite being generated by different laboratories using different methodologies - can be made comparable to each other. This meta-analytic approach to RNA-seq can be extended with new datasets from novel tissues, and is applicable to any species.
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