Whole transcriptome response of chicken spleen and peripheral blood leukocytes to avian pathogenic Escherichia coli

A greater understanding of the immune response after infection can form the necessary foundation of knowledge needed to enhance immunity through genetic selection. Whole genome microarrays allow for comprehensive analysis of the transcriptome. The transcriptomic responses of spleen and peripheral blood leukocytes (PBL) each displayed differential expression in broiler chickens infected with avian pathogenic Escherichia coli (APEC), the causative agent for colibacillosis. This differential expression was associated with treatment factors of infection status, pathology level and day post-infection. Within the spleen, the largest number of significantly differentially expressed genes was between chickens with a severe pathology and those uninfected: 1,101 genes at 1 day post-infection and 1,723 genes at 5 days post-infection. Significant differences in splenic expression between mild and severe pathology was only noted at 5 days post-infection, for 799 genes. Within PBL, the largest number of significantly differentially expressed genes was between mild and severe pathology on day 5, for 1,914 genes. Significant differences in expression were also noted between severe pathology and uninfected chickens, for 1,097 genes at 1 day post-infection and for 506 genes at 5 days post-infection. In both tissues, a severe pathological state resulted in more induction of gene expression response than repression. Several immune-related gene families, including the Toll-like receptors, cytokines and beta-defensins, were differentially expressed in both tissues. Combining results from the two tissues revealed potential pathway regulation between tissues over time. MAPK pathway signaling in PBL at 1 day post-infection, could be causative for the downstream cytokine and p53 pathway signaling observed in the spleen at 5 days post-infection. Vaccination against an APEC virulence factor generated no discernible difference in gene expression in either tissue, with or without other factors of day, challenge, or pathology, although it was efficacious in reducing pathology, indicating further research is necessary to identify the impact of APEC vaccination on the transcriptome. Combining this knowledge with genotypic markers could help to reveal the genomic locations responsible for conveying APEC resistance, allowing breeders to use this information to reduce the incidence of APEC infection in poultry

SNPs in Region of NF-Kappa-B Gene Associated with Expression of Immune-Related Genes

Selection to enhance immune response is difficult. Gene expression was assessed in two advanced intercross lines of chickens for various immune-related genes. Single nucleotide polymorphisms, SNPs, were identified in regions local to each gene and around a distant transcription factor, NF-Kappa-B, NFKB. These SNPs were used to identify expression QTL, eQTL, to aid in selection of immune gene expression. These eQTL may provide effective resources to which marker assisted selection may be applied

Strong Concordance Between Transcriptomic Patterns of Spleen and Peripheral Blood Leukocytes in Response to Avian Pathogenic Escherichia coli Infection

Avian pathogenic Escherichia coli (APEC) causes morbidity in chickens and exhibits zoonotic potential. Understanding host transcriptional responses to infection aids the understanding of protective mechanisms and serves to inform future colibacillosis control strategies. Transcriptomes of spleen and peripheral blood leukocytes (PBLs) of the same individual birds in response to APEC infection were compared to identify common response patterns and connecting pathways. More than 100 genes in three contrasts examining pathology and infection status were significantly differentially expressed in both tissues and similarly regulated. Tissue-specific differences in catalytic activity, however, appear between birds with mild and severe pathology responses. Early expression differences, between birds with severe pathology and uninfected controls, in the mitogen-activated protein kinase pathway in PBLs precede spleen responses in the p53 and cytokine-cytokine receptor pathways. Tissue bianalysis is useful in identifying genes and pathways important to the response to APEC, whose role might otherwise be underestimated in importance

Extent and consistency of linkage disequilibrium and identification of DNA markers for production and egg quality traits in commercial layer chicken populations

A 3,072 single nucleotide polymorphism (SNP) panel was used to identify genetic markers linked to quantitative trait loci (QTL). Two association methods were used to search for QTL, SNP-wise and genome-wise models. The QTL associated with SNPs, found using both of these methods, can be applied to breeding programs in marker assisted selection (MAS). The extent and consistency of linkage disequilibrium (LD) was measured in two lines of commercial egg laying chickens by analysis of SNPs. Correlations were drawn between measurements of two consecutive years to determine consistency. At short distances, LD is retained which allows for markers at high LD with a trait to be effectively applied in MAS

Leukocyte transcriptome from chickens infected with avian pathogenic Escherichia coli identifies pathways associated with resistance

Avian pathogenic Escherichia coli (APEC) causes colibacillosis, which is responsible for morbidity and mortality in chickens. Gene expression patterns have previously been demonstrated to differ between chicken populations that are resistant vs. susceptible to bacterial infection, but little is currently known about gene expression response to APEC. Increased understanding of gene expression patterns associated with resistance will facilitate genetic selection to increase resistance to APEC. Male broiler chicks were vaccinated at 2 weeks of age and challenged with APEC at 4 weeks of age. Peripheral blood leukocytes were collected at 1 and 5 day post-infection. Lesions on the liver, pericardium, and air sacs were used to assign a mild or severe pathology status to non-vaccinated, challenged chicks. Ten treatment groups were therefore generated with a priori factors of vaccination, challenge, day post-infection, and the a posteriori factor of pathology status. Global transcriptomic response was evaluated using the Agilent 44K chicken microarray. APEC infection resulted in more up-regulation than down-regulation of differentially expressed genes. Immune response and metabolic processes were enriched with differentially expressed genes. Although vaccination significantly reduced lesions in challenged bird, there was no detectable effect of vaccination on gene expression. This study investigated the transcriptomic differences in host responses associated with mild vs. severe pathology, in addition to the effects of vaccination and challenge, thus revealing genes and networks associated with response to APEC and providing a foundation for future studies on, and genetic selection for, genetic resistance to APEC

Parental Smoking Modifies the Relation between Genetic Variation in Tumor Necrosis Factor-α (TNF) and Childhood Asthma

BACKGROUND: Polymorphisms in the proinflammatory cytokine genes tumor necrosis factor-α (TNF) and lymphotoxin-α (LTA, also called TNF-β) have been associated with asthma and atopy in some studies. Parental smoking is a consistent risk factor for childhood asthma. Secondhand smoke and ozone both stimulate TNF production. OBJECTIVES: Our goal was to investigate whether genetic variation in TNF and LTA is associated with asthma and atopy and whether the association is modified by parental smoking in a Mexican population with high ozone exposure. METHODS: We genotyped six tagging single nucleotide polymorphisms (SNPs) in TNF and LTA, including functional variants, in 596 nuclear families consisting of asthmatics 4–17 years of age and their parents in Mexico City. Atopy was determined by skin prick tests. RESULTS: The A allele of the TNF-308 SNP was associated with increased risk of asthma [relative risk (RR) = 1.54; 95% confidence interval (CI), 1.04–2.28], especially among children of non-smoking parents (RR = 2.06; 95% CI, 1.19–3.55; p for interaction = 0.09). Similarly, the A allele of the TNF-238 SNP was associated with increased asthma risk among children of nonsmoking parents (RR = 2.21; 95% CI, 1.14–4.30; p for interaction = 0.01). LTA SNPs were not associated with asthma. Haplotype analyses reflected the single SNP findings in magnitude and direction. TNF and LTA SNPs were not associated with the degree of atopy. CONCLUSIONS: Our results suggest that genetic variation in TNF may contribute to childhood asthma and that associations may be modified by parental smoking

Improved prediction of radiation pneumonitis by combining biological and radiobiological parameters using a data-driven Bayesian network analysis

Grade 2 and higher radiation pneumonitis (RP2) is a potentially fatal toxicity that limits efficacy of radiation therapy (RT). We wished to identify a combined biomarker signature of circulating miRNAs and cytokines which, along with radiobiological and clinical parameters, may better predict a targetable RP2 pathway. In a prospective clinical trial of response-adapted RT for patients (n = 39) with locally advanced non-small cell lung cancer, we analyzed patients\u27 plasma, collected pre- and during RT, for microRNAs (miRNAs) and cytokines using array and multiplex enzyme linked immunosorbent assay (ELISA), respectively. Interactions between candidate biomarkers, radiobiological, and clinical parameters were analyzed using data-driven Bayesian network (DD-BN) analysis. We identified alterations in specific miRNAs (miR-532, -99b and -495, let-7c, -451 and -139-3p) correlating with lung toxicity. High levels of soluble tumor necrosis factor alpha receptor 1 (sTNFR1) were detected in a majority of lung cancer patients. However, among RP patients, within 2 weeks of RT initiation, we noted a trend of temporary decline in sTNFR1 (a physiological scavenger of TNFα) and ADAM17 (a shedding protease that cleaves both membrane-bound TNFα and TNFR1) levels. Cytokine signature identified activation of inflammatory pathway. Using DD-BN we combined miRNA and cytokine data along with generalized equivalent uniform dose (gEUD) to identify pathways with better accuracy of predicting RP2 as compared to either miRNA or cytokines alone. This signature suggests that activation of the TNFα-NFκB inflammatory pathway plays a key role in RP which could be specifically ameliorated by etanercept rather than current therapy of non-specific leukotoxic corticosteroids

Mutation in \u3ci\u3eATG5\u3c/i\u3e reduces autophagy and leads to ataxia with developmental delay

Autophagy is required for the homeostasis of cellular material and is proposed to be involved in many aspects of health. Defects in the autophagy pathway have been observed in neurodegenerative disorders; however, no genetically-inherited pathogenic mutations in any of the core autophagy-related (ATG) genes have been reported in human patients to date. We identified a homozygous missense mutation, changing a conserved amino acid, in ATG5 in two siblings with congenital ataxia, mental retardation, and developmental delay. The subjects’ cells display a decrease in autophagy flux and defects in conjugation of ATG12 to ATG5. The homologous mutation in yeast demonstrates a 30-50% reduction of induced autophagy. Flies in which Atg5 is substituted with the mutant human ATG5 exhibit severe movement disorder, in contrast to flies expressing the wild-type human protein. Our results demonstrate the critical role of autophagy in preventing neurological diseases and maintaining neuronal health

Mutations in VPS13D lead to a new recessive ataxia with spasticity and mitochondrial defects

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145306/1/ana25220_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145306/2/ana25220.pd

Spleen transcriptome response to infection with avian pathogenic Escherichia coli in broiler chickens

<p>Abstract</p> <p>Background</p> <p>Avian pathogenic <it>Escherichia coli </it>(APEC) is detrimental to poultry health and its zoonotic potential is a food safety concern. Regulation of antimicrobials in food-production animals has put greater focus on enhancing host resistance to bacterial infections through genetics. To better define effective mechanism of host resistance, global gene expression in the spleen of chickens, harvested at two times post-infection (PI) with APEC, was measured using microarray technology, in a design that will enable investigation of effects of vaccination, challenge, and pathology level.</p> <p>Results</p> <p>There were 1,101 genes significantly differentially expressed between severely infected and non-infected groups on day 1 PI and 1,723 on day 5 PI. Very little difference was seen between mildly infected and non-infected groups on either time point. Between birds exhibiting mild and severe pathology, there were 2 significantly differentially expressed genes on day 1 PI and 799 on day 5 PI. Groups with greater pathology had more genes with increased expression than decreased expression levels. Several predominate immune pathways, Toll-like receptor, Jak-STAT, and cytokine signaling, were represented between challenged and non-challenged groups. Vaccination had, surprisingly, no detectible effect on gene expression, although it significantly protected the birds from observable gross lesions. Functional characterization of significantly expressed genes revealed unique gene ontology classifications during each time point, with many unique to a particular treatment or class contrast.</p> <p>Conclusions</p> <p>More severe pathology caused by APEC infection was associated with a high level of gene expression differences and increase in gene expression levels. Many of the significantly differentially expressed genes were unique to a particular treatment, pathology level or time point. The present study not only investigates the transcriptomic regulations of APEC infection, but also the degree of pathology associated with that infection. This study will allow for greater discovery into host mechanisms for disease resistance, providing targets for marker assisted selection and advanced drug development.</p