Sputum Proteomics Reveals a Shift in Vitamin D-binding Protein and Antimicrobial Protein Axis in Tuberculosis Patients.

Existing understanding of molecular composition of sputum and its role in tuberculosis patients is variously limited to its diagnostic potential. We sought to identify infection induced sputum proteome alteration in active/non tuberculosis patients (A/NTB) and their role in altered lung patho-physiology. Out of the study population (n = 118), sputum proteins isolated from discovery set samples (n = 20) was used for an 8-plex isobaric tag for relative and absolute concentration analysis. A minimum set of protein with at least log2(ATB/NTB) >±1.0 in ATB was selected as biosignature and validated in 32 samples. Predictive accuracy was calculated from area under the receiver operating characteristic curve (AUC of ROC) using a confirmatory set (n = 50) by Western blot analysis. Mass spectrometry analysis identified a set of 192 sputum proteins, out of which a signature of ß-integrin, vitamin D binding protein:DBP, uteroglobin, profilin and cathelicidin antimicrobial peptide was sufficient to differentiate ATB from NTB. AUC of ROC of the biosignature was calculated to 0.75. A shift in DBP-antimicrobial peptide (AMP) axis in the lungs of tuberculosis patients is observed. The identified sputum protein signature is a promising panel to differentiate ATB from NTB groups and suggest a deregulated DBP-AMP axis in lungs of tuberculosis patients.

Global Urine Metabolomics in Patients Treated with First-Line Tuberculosis Drugs and Identification of a Novel Metabolite of Ethambutol.

Population level variation of drug metabolism phenotype (DMP) has great implications in treatment outcome, drug-related side effects, and resistance development. In this study, we used a gas chromatography-time of flight-mass spectrometry (GC-TOF-MS)-based untargeted urine metabolomics approach to understand the DMP of a tuberculosis (TB) patient cohort (n= 20) from Tripura, a state in the northeastern part of India. Urine samples collected at different postdose time points (2 h, 6 h, 12 h, 24 h, 36 h, and 48 h) from these newly diagnosed TB patients receiving first-line anti-TB drugs were analyzed, and we have successfully detected three of the four first-line drugs,viz, isoniazid (INH), ethambutol (ETB), and pyrazinamide (PZA). The majority of their known metabolites, acetyl-isoniazid (AcINH), isonicotinic acid (INA), isonicotinuric acid (INTA), 2,2'-(ethylenediimino)-dibutyric acid (EDBA), 5-hydroxypyrazinamide (5OH-PZA), pyrazinoic acid (POA), and 5-hydroxypyrazinoic acid (5OH-POA), were also detected. Analyzing the variation in abundances of drugs and their known metabolites and calculating the metabolic ratios in these samples, we offer comprehensive DMP information on this small patient cohort that represents Tripura, India. The majority (75%) of these patients are found to be slow acetylators of INH. The average metabolic ratios of POA/PZA and 5OH-POA/POA are 3.16 ± 3.03 and 6.09 ± 6.15, respectively. Employing correlation analysis of the metabolomics metadata and a manual prediction of drug catabolism, we have proposed 2-aminobutyric acid (AABA) as a novel metabolite of ETB. These observations indicate the usefulness of GC-MS-based metabolomics to characterize the DMP at a population level and also to identify novel drug metabolites.