Project description:Background: Tuberculosis (TB) remains a major public health problem, especially in developing countries, with 1.5 million deaths annually worldwide. Antibiotics are commonly used in the treatment of bacterial infections. As with most drugs, antibiotic treatment can also alter host metabolism, leading to adverse side-effects. Antibiotics can also interfere with the immune system, indirectly through the disturbance of the body’s microbiota or directly by modulating the functions of immune cells. It is therefore important to understand how antibiotic treatment modulates immune cell functions. Here we aim to evaluate the impact of first-line anti-TB drugs on the response of human macrophages infected with Mycobacterium tuberculosis (MTB). Results: Human macrophages were stimulated with heat-killed Mycobacterium tuberculosis (hk-MTB) and treated with isoniazid (INH), rifampicin (RIF), ethambutol, pyrazinamide (PZA) or amikacin (AMK). After 24h of treatment, RNA was collected and we characterized the genome-wide gene expression profiles of drug-treated cells by RNAseq. 556, 752 and 7 genes were differentially expressed in hk-MTB-stimulated macrophages upon RIF, PZA and EMB treatment respectively, whereas in uninfected macrophages, 448 and 11 genes were differentially expressed upon RIF and PZA treatment respectively. No genes were differentially expressed upon INH and AMK treatment. We classified all modulated genes by performing gene-set enrichment analysis. The gene set regulated by PZA in infected macrophages was significantly enriched for genes involved in Integral to lumenal side of endoplasmic reticulum membrane, Cytokine-mediated signaling pathway or Interferon-gamma-mediated signaling pathway. In hk-MTB-stimulated macrophages treated by RIF, we found an enrichment in Endoplasmic reticulum unfolded protein response, NADP binding or Lipid metabolic process. Conclusions: Our results highlight the importance to understand how antibiotic treatment modulates macrophage (Mφ) functions, and more generally, how it impacts the host immune response.

Project description:Despite more than a century fighting against tuberculosis, the World Health Organisation has estimated that around 1.7 million people died of tuberculosis in 2016 and over a quarter of the world’s population is infected. One of the critical hurdles for stopping tuberculosis transmission is early and effective diagnosis of patients with the active pulmonary disease. Although important innovations in molecular diagnosis have been recently developed (e.g. Xpert MTB/RIF, Cepheid Inc., USA), there are no suitable tests for population screening at point-of-care. The current tuberculosis diagnosis pipeline presents a highly variable performance and requires access to reference laboratory facilities. A non-sputum based rapid test with high specificity and sensitivity could save ~400,000 lives per year. Therefore, new biomarkers for diagnosis are urgently required for identifying patients with early symptoms and to expedite treatment. Variable sensitivity and specificity can be overcome using a combination of multiple biomarkers (5). Proteins, as ultimate biological effectors, are ideal candidates for diagnostic biomarkers; consequently, proteomic studies are a crucial platform for biomarker discovery in tuberculosis. This work aims to develop a multi-marker panel for tuberculosis diagnosis with high performance capable of differentiating tuberculosis patients from relevant controls. Quantitative Multidimensional Protein Identification Technology (qMudPIT) is applied for biomarker discovery identifying candidates for early diagnosis of tuberculosis. The multidimensional method optimised in this work led to the identification of 5022 plasma proteins and 3577 quantified proteins using iTRAQ labelling. Known and completely novel markers for active tuberculosis in plasma were identified including a peptide derived from Mycobacterium tuberculosis. Complementary statistical and bioinformatic analysis were applied to prioritise candidates for validation in one or two independent cohorts. The plasma proteomic profile here described represents a power strategy for biomarker discovery and the panel proposed has the potential to be translated to a rapid test and which might contribute to tuberculosis control.

Project description:Tuberculosis (TB) still represents a major global health problem affecting over 10 million people worldwide. At present, there is an urgent need for defining prognostic parameters, differential diagnostic, and correlates of protection from the disease. The gold standard test for TB diagnosis is still smear microscopy, but insufficiently detects pulmonary disease, besides the necessity of having laboratory infrastructures and be time-consuming. Both LAM urine test and Xpert MTB/RIF have been major game changers in this context. However, the low sensitivity of the former and the considerable delay of sample delivery of the latter, make the improvement of the TB diagnostic landscape a priority. The development of rapid point-of-care (POC)-based testing approaches would represent an important breakthrough in TB diagnostics in view of these short-comings. Most forms of life produce extracellular vesicles (EVs) and since the first detection of bacterial EVs more than 60 years, subsequent studies have demonstrated their functional commonality despite differences in bacterial cell envelope architecture. We demonstrated that Mycobacterium tuberculosis (Mtb), the causative agent of TB, produces EVs in vitro and in vivo as part of a sophisticated mechanism to manipulate host cellular physiology and to evade the host immune system. In a previous serology study, Mtb EVs (MEVs) were used to investigate their potential role as biomarkers to discern between different forms of disease status. It was shown that the recognition of several MEV associated proteins could have diagnostic properties. In this study, we pursued to expand the capabilities of MEVs in the context of TB diagnostics by analyzing the composition of MEVs isolated from Mtb cultures submitted to iron starvation and, testing their immunogenicity against a new cohort of serum samples including TB+, LTBI and healthy donors. We found that MEVs differ in protein composition when Mtb is under host-related stress yet MEVs seem to carry antigens that could serve as bonafide markers for direct detection. In addition, TB serology revealed three new MEV antigens with great biomarker capacity. These results encourage investigating the feasibility of the development of a POC device based on selected MEV-associated proteins.

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