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Objective: To better characterize the cerebrospinal fluid (CSF) metabolic profile of tuberculous meningitis (TBM) cases using a South African paediatric cohort.Methods: 1H NMR metabolomics was used to analyse the CSF of a South African paediatric cohort. Univariate and multivariate statistical analyses were performed to compare a homogeneous control group with a well-defined TBM group.Results: Twenty metabolites were identified to discriminate TBM cases from controls. As expected, reduced glucose and elevated lactate were the dominating discriminators. A closer investigation of the CSF metabolic profile yielded 18 metabolites of statistical significance. Ten metabolites (acetate, alanine, choline, citrate, creatinine, isoleucine, lysine, myo-inositol, pyruvate and valine) overlapped with two other prior investigations. Eight metabolites (2-hydroxybutyrate, carnitine, creatine, creatine phosphate, glutamate, glutamine, guanidinoacetate and proline) were unique to our paediatric TBM cohort.Conclusions: Through strict exclusion criteria, quality control checks and data filtering, eight unique CSF metabolites associated with TBM were identified for the first time and linked to: uncontrolled glucose metabolism, upregulated proline and creatine metabolism, detoxification and disrupted glutamate-glutamine cycle in the TBM samples. Associated with oxidative stress and chronic neuroinflammation, our findings collectively imply destabilization, and hence increased permeability, of the blood-brain barrier in the TBM cases. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis (M. tuberculosis) curli pili (MTP) is a surface located adhesin, which is involved in the initial point-of-contact between the pathogen and the host. Host-pathogen interaction is essential for establishing infection. M. tuberculosis has the ability to infect various host lung cell types, which includes both the epithelial cells and macrophages, and subsequent differences in their cellular function will be evident in their metabolic profiles. Understanding the differences between these cell types and their individual metabolic response to M. tuberculosis infection, with and without the presence of the MTP, will aid to better elucidate the role of this adhesin in modulating metabolic pathways during infection. This may further contribute to the development of improved diagnostic and therapeutic interventions, much needed at present in order to improve control the global tuberculosis (TB) epidemic. This study used a two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) metabolomics approach to compare the metabolite profiles of A549 epithelial cells to that of THP-1 macrophages, infected with M. tuberculosis, in the presence and absence of MTP. Significant metabolites were identified using various univariate and multivariate statistical analysis. A total of 44, 40, 50 and 34 metabolites were differentially detected when comparing the (a) uninfected A549 epithelial cells to uninfected THP-1 macrophages, (b) wild-type infected A549 epithelial cells to wild-type infected THP-1 macrophages, (c) ∆ mtp -infected A549 epithelial cells to ∆ mtp -infected THP-1 macrophages (d) complement-infected A549 epithelial cells to complement-infected THP-1 macrophages, respectively. These included metabolites that were involved in amino acid metabolism, fatty acid metabolism, general central carbon metabolism, and nucleic acid metabolism. In the absence of the M. tuberculosis MTP adhesin, the THP-1 macrophages predominantly displayed higher concentrations of amino acids and their metabolic intermediates, than the A549 epithelial cells. The deletion of MTP from M. tuberculosis in the host infection models potentially elicited a pro-inflammatory phenotype, particularly in the macrophage model. In the presence of MTP, the metabolite profile changes indicate potential regulation of host defence mechanisms, accompanied by a reduction in microbicidal abilities of host cells. Hence MTP can be considered a virulence factor of M. tuberculosis. Therefore, blocking MTP interaction with the host may facilitate a faster pathogen clearance during the initial stages of infection, and potentially enhance current therapeutic interventions. • THP-1 macrophages compared to A549 epithelial cells infected with M. tuberculosis. • Influence of MTP adhesin on the host-pathogen metabolic profiles. • MTP reduces microbicidal abilities. • Mycobacterium tuberculosis curli pili is a virulence factor of M. tuberculosis. [ABSTRACT FROM AUTHOR]