Comprehensive Examination of the Mouse Lung Metabolome Following Mycobacterium tuberculosis Infection Using a Multiplatform Mass Spectrometry Approach

Abstract

The mechanisms whereby Mycobacterium tuberculosis (Mtb) rewires the host metabolism in vivo are surprisingly unexplored. Here, we used three high-resolution mass spectrometry platforms to track altered lung metabolic changes associated with Mtb infection of mice. The multiplatform data sets were merged using consensus orthogonal partial least squares-discriminant analysis (cOPLS-DA), an algorithm that allows for the joint interpretation of the results from a single multivariate analysis. We show that Mtb infection triggers a temporal and progressive catabolic state to satisfy the continuously changing energy demand to control infection. This causes dysregulation of metabolic and oxido-reductive pathways culminating in Mtb-associated wasting. Notably, high abundances of trimethylamine-N-oxide (TMAO), produced by the host from the bacterial metabolite trimethylamine upon infection, suggest that Mtb could exploit TMAO as an electron acceptor under anaerobic conditions. Overall, these new pathway alterations advance our understanding of the link between Mtb pathogenesis and metabolic dysregulation and could serve as a foundation for new therapeutic intervention strategies. Mass spectrometry data has been deposited in the Metabolomics Workbench repository (data-set identifier: ST001328).

Insights gained into respiratory infection pathogenesis using lung tissue metabolomics

“…Lung metabolome characterization in bacterial infections has been performed in Mycobacterium tuberculosis infection (four studies, two in guinea pigs [12,13] and two in C57BL/6 mice [14,15]), using NMR [12,13,14] and capillary electrophoresis-mass spectrometry (CE-MS), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS) [15]; in Pseudomonas aeruginosa infection (two studies in C57BL/6 mice, one using NMR [16] and one using time-of-flight-secondary ion mass spectrometry (TOF-SIMS)MS [17]); and in Francisella tularensis infection in ICR mice using desorption electrospray ionization-mass spectrometry (DESI-MS) [18]. Given the common methods employed in most of the M. tuberculosis studies, significant overlap in infection-induced metabolic shifts was observed, including increases in lactate, glutamate, aspartate, glutathione, and betaine (Table 1) [12,13,14,15]. Increases in oxidized glutathione are likely due to inflammatory processes [12,15], and increases in amino acids may reflect increased proteolysis [15].…”

“…Given the common methods employed in most of the M. tuberculosis studies, significant overlap in infection-induced metabolic shifts was observed, including increases in lactate, glutamate, aspartate, glutathione, and betaine (Table 1) [12,13,14,15]. Increases in oxidized glutathione are likely due to inflammatory processes [12,15], and increases in amino acids may reflect increased proteolysis [15]. Succinate was also increased in P. aeruginosa infection, whereas glutathione was decreased [16].…”

“…Indeed, serum metabolomic studies of COVID-19 patients have revealed major alterations in the plasma and serum metabolome and lipidome, with decreased circulating amino acids in particular [24,25]. Although select amino acids were decreased in lung P. aeruginosa and influenza virus infection [16] [5], lung amino acids were predominantly increased by respiratory pathogens [6,9,11,12,13,14,15,16]. In contrast, metabolite shifts common to COVID-19 patient blood and experimental lung infections include increases in some nucleotide metabolites (also observed in the works by Cui and colleagues and Chandler and colleagues [6,9]) and decreases in allantoin and mannitol (also observed in Tisoncik-Go and colleagues and Chandler and colleagues [5,9]) [25].…”

“…Examples of diseases which display similar changes in specific lung metabolites during infection include RSV in BALB/c mice [11] and influenza virus in C57BL/6 mice [9] (indole increased), M. tuberculosis [12,13] and Cryptococcus [19] (acetic acid increased), P. aeruginosa [16] and M. tuberculosis [14] (succinate increased), M. tuberculosis [14], P. aeruginosa [16] and influenza virus [6] (leucine increased), M. tuberculosis [14] and influenza virus [5,6] (lactic acid, taurine, uridine, and phosphatidylethanolamine increased), and RSV [11] and P. aeruginosa [16] (glycine decreased) ( Table 1). Kynurenine was increased by influenza virus [6,9], RSV [11], and M. tuberculosis [15] infection, likely due to the fact that it is produced in response to inflammation. Indeed, increased kynurenine is also observed in the serum of severe COVID-19 patients [24].…”

“…Lung metabolome characterization in bacterial infections has been performed in Mycobacterium tuberculosis infection (four studies, two in guinea pigs [ 12 , 13 ] and two in C57BL/6 mice [ 14 , 15 ]), using NMR [ 12 , 13 , 14 ] and capillary electrophoresis–mass spectrometry (CE-MS), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS) [ 15 ]; in Pseudomonas aeruginosa infection (two studies in C57BL/6 mice, one using NMR [ 16 ] and one using time-of-flight-secondary ion mass spectrometry (TOF-SIMS)MS [ 17 ]); and in Francisella tularensis infection in ICR mice using desorption electrospray ionization-mass spectrometry (DESI-MS) [ 18 ]. Given the common methods employed in most of the M .…”