Experimental infection of cattle with Mycobacterium tuberculosis isolates shows the attenuation of the human tubercle bacillus for cattle

The Mycobacterium tuberculosis complex (MTBC) is the collective term given to the group of bacteria that cause tuberculosis (TB) in mammals. It has been reported that M. tuberculosis H37Rv, a standard reference MTBC strain, is attenuated in cattle compared to Mycobacterium bovis. However, as M. tuberculosis H37Rv was isolated in the early 1930s, and genetic variants are known to exist, we sought to revisit this question of attenuation of M. tuberculosis for cattle by performing a bovine experimental infection with a recent M. tuberculosis isolate. Here we report infection of cattle using M. bovis AF2122/97, M. tuberculosis H37Rv, and M. tuberculosis BTB1558, the latter isolated in 2008 during a TB surveillance project in Ethiopian cattle. We show that both M. tuberculosis strains caused reduced gross and histopathology in cattle compared to M. bovis. Using M. tuberculosis H37Rv and M. bovis AF2122/97 as the extremes in terms of infection outcome, we used RNA-Seq analysis to explore differences in the peripheral response to infection as a route to identify biomarkers of progressive disease in contrast to a more quiescent, latent infection. Our work shows the attenuation of M. tuberculosis strains for cattle, and emphasizes the potential of the bovine model as a ‘One Health’ approach to inform human TB biomarker development and post-exposure vaccine development

Characterisation of the innate immune response to Campylobacter jejuni colonisation in the chicken intestine

THESIS 9084Campylobacter jejuni is the leading cause of gastroenteritis in humans, and chickens are the primary vector for infection. The microbe colonises the caeca of birds as a commensal, and it is hypothesised that intestinal defences regulate colonisation. Identifying birds with enhanced abilities to clear C. jejuni would enable the selective breeding of colonisation resistant birds. However, the caecal immune response to C. jejuni has been poorly characterised to date and is the basis of this thesis

Global gene expression analysis of chicken caecal response to Campylobacter jejuni

Campylobacter jejuni colonises the caecum of more than 90% of commercial chickens. Even though colonisation is asymptomatic, we hypothesised that it is mediated by activation of several biological pathways. We therefore used chicken-specific 20 K oligonucleotide microarrays to examine global gene expression in C. jejuni-challenged birds. Microarray results demonstrate small but significant fold-changes in expression of 270 genes 20 hours post-challenge, corresponding to a wide range of biological processes including cell growth, nutrient metabolism and immunological activity. Expression of NOX1 (2.3-fold) and VCAM1 (1.5-fold) were significantly increased in colonised birds (P < 0.05), indicating oxidative burst and endothelial cell activation, respectively. Microarray results, supplemented by qRT-PCR analyses demonstrated increased TOPK (1.9-fold), IL17 (3.6-fold), IL21 (2.1-fold), IL7R (4-fold) and CTLA4 (2.5-fold) gene expression (P < 0.05), which was suggestive of T cell mediated activity. Combined these results suggest that C. jejuni has nominal effects on global caecal gene expression in the chicken but significant changes detected are suggestive of a protective intestinal T cell response

Analysis of biobanked serum from a mycobacterium avium subsp paratuberculosis bovine infection model confirms the remarkable stability of circulating mirna profiles and defines a bovine serum mirna repertoire

Johne's Disease (JD) is a chronic enteritis of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). Current disease control strategies are hampered by the lack of sensitive and specific diagnostic modalities. Therefore, novel diagnostic and prognostic tools are needed, and circulating microRNAs (miRNAs) may hold potential in this area. The aims of this study were twofold: (i) to address the stability of miRNA in bovine sera from biobanked samples, and (ii) to assess the potential of miRNAs as biomarkers for JD disease progression. To address these aims we used bovine sera from an experimental MAP infection model that had been stored at -20°C for over a decade, allowing us to also assess the stability of miRNA profiles in biobanked serum samples through comparison with fresh sera. Approximately 100â€"200 intact miRNAs were identified in each sample with 83 of these being consistently detected across all 57 samples. The miRNA profile of the biobanked sera stored at -20°C for over 10 years was highly similar to the profile o

Interplay Between the Autophagy-Lysosomal Pathway and the Ubiquitin-Proteasome System: A Target for Therapeutic Development in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common cause of age-related dementia leading to severe irreversible cognitive decline and massive neurodegeneration. While therapeutic approaches for managing symptoms are available, AD currently has no cure. AD associates with a progressive decline of the two major catabolic pathways of eukaryotic cells—the autophagy-lysosomal pathway (ALP) and the ubiquitin-proteasome system (UPS)—that contributes to the accumulation of harmful molecules implicated in synaptic plasticity and long-term memory impairment. One protein recently highlighted as the earliest initiator of these disturbances is the amyloid precursor protein (APP) intracellular C-terminal membrane fragment β (CTFβ), a key toxic agent with deleterious effects on neuronal function that has become an important pathogenic factor for AD and a potential biomarker for AD patients. This review focuses on the involvement of regulatory molecules and specific post-translational modifications (PTMs) that operate in the UPS and ALP to control a single proteostasis network to achieve protein balance. We discuss how these aspects can contribute to the development of novel strategies to strengthen the balance of key pathogenic proteins associated with AD

Canonical and dominant isomiR differences.

<p>A) bta-miR-22-3p total abundance profile over time (left) and for 2 isomiRs (right), both are shorter 3’ variants. Analysing these isomiRs individually allows them to be detected as being differentially expressed over time. B) bta-miR-22-3p isomiR relative abundances. The canonical form, labelled <i>exact</i>, is only fourth most abundant. C) The canonical and dominant isomiRs differ in >50% of cases. Shown in the plot are the corresponding percentages between the 2 isoforms, when different. (By definition <i>dominant</i> means highest percentage of reads). For points in the top left of the plots, the actual canonical form is insignificant. Note the lower number of points for the 10–15 year (CVI) dataset.</p

IsomiR abundances and variant representation in different datasets.

<p>A) IsomiR normalised counts compared between 1) fresh (-80°C/<1 year storage) and biobanked (-20°C/>10 year storage) bovine serum, 2) serum and macrophage (both bovine) and 3) bovine and human serum. B) Classification scheme for isomiRs using sRNAbench is hierarchical. <i>exactNucVar</i> means single nucleotide changes to the canonical sequence, most probably due to sequencing errors. <i>mv</i> indicates shifted sequences. non-templated addition is enzymatically addition of a nucleotide to the 3’ end and is given priority by sRNAbench since these changes may be of biological relevance. C) Plot shows the counts of dominant isomiRs categorised by class. The general trend of dominance is the same across all datasets, including non-serum.</p