Serum Small Extracellular Vesicles Proteome of Tuberculosis Patients Demonstrated Deregulated Immune Response

Detailed understanding of host pathogen interaction in tuberculosis is an important avenue for identifying novel therapeutic targets. Small extracellular vesicles (EVs) like exosomes that are rich in proteins, nucleic acids and lipids, act as messengers and may show altered composition in disease conditions.

In this case control study, small EVs are isolated from serum of 58 subjects (all male, 33 (15-70) in years) including drug naïve active tuberculosis (ATB: n = 22), non-tuberculosis (NTB: n = 18), and healthy subjects (n = 18). Serum small EVs proteome analysis is carried out using isobaric tag for relative and absolute quantification (iTRAQ) experiments and an independent sample (n = 36) is used for validation.

A set of 132 and 68 proteins are identified in iTRAQ-I (ATB/Healthy) and iTRAQ-II (ATB/NTB) experiments, respectively. Four proteins (KYAT3, SERPINA1, HP, and APOC3) show deregulation (log₂ -fold change > ±0.48, p < 0.05) in ATB with respect to healthy controls and Western blot data corroborated mass spectrometry findings.

These important proteins, involved in neutrophil degranulation, plasma heme scavenging, kynurenine, and lipid metabolism, show deregulation in ATB patients. Identification of such a protein panel in circulating small EVs besides providing novel insights into their role in tuberculosis may prove to be useful targets to develop host-directed therapeutic intervention.