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Updated: Jul 4, 2025
Preparation of Mycobacterium Tuberculosis Culture Filtrate to Understand TB Pathogenesis
Published on: March 28, 2025
Mycobacterium tuberculosis PE_PGRS45 (Rv2615c) Promotes Recombinant Mycobacteria Intracellular Survival via
Tao Xu1, Chutong Wang1, Minying Li1
1Anhui Provincial Key Laboratory of Immunology in Chronic Diseases, Research Center of Laboratory Medicine, School of Laboratory Medicine, Bengbu Medical University, Bengbu, 233030, People's Republic of China.
Abstract:
Tuberculosis (TB), a bacterial infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis), is a significant global public health problem. Mycobacterium tuberculosis expresses a unique family of PE_PGRS proteins that have been implicated in pathogenesis. Despite numerous studies, the functions of most PE_PGRS proteins in the pathogenesis of mycobacterium infections remain unclear. PE_PGRS45 (Rv2615c) is only found in pathogenic mycobacteria. In this study, we successfully constructed a recombinant Mycobacterium smegmatis (M. smegmatis) strain which heterologously expresses the PE_PGRS45 protein. We found that overexpression of this cell wall-associated protein enhanced bacterial viability under stress in vitro and cell survival in macrophages. MS_PE_PGRS45 decreased the secretion of pro-inflammatory cytokines such as IL-1β, IL-6, IL-12p40, and TNF-α. We also found that MS_PE_PGRS45 increased the expression of the anti-inflammatory cytokine IL-10 and altered macrophage-mediated immune responses. Furthermore, PE_PGRS45 enhanced the survival rate of M. smegmatis in macrophages by inhibiting cell apoptosis. Collectively, our findings show that PE_PGRS45 is a virulent factor actively involved in the interaction with the host macrophage.
Insights
The PE_PGRS45 protein from Mycobacterium tuberculosis enhances bacterial survival under stress and within macrophages. This virulence factor modulates host immune responses by reducing pro-inflammatory cytokines and inhibiting apoptosis.
Area of Science:
- Microbiology
- Immunology
- Pathogenesis
Background:
- Tuberculosis (TB) is a major global health issue caused by Mycobacterium tuberculosis.
- The PE_PGRS protein family of M. tuberculosis plays a role in pathogenesis, but functions remain largely unknown.
- PE_PGRS45 is a unique protein found exclusively in pathogenic mycobacteria.
Purpose of the Study:
- To investigate the function of PE_PGRS45 in mycobacterial pathogenesis.
- To determine the role of PE_PGRS45 in host-pathogen interactions, specifically with macrophages.
Main Methods:
- Construction of a recombinant Mycobacterium smegmatis strain expressing PE_PGRS45.
- Assessment of bacterial viability under stress conditions in vitro.
- Evaluation of bacterial survival and host immune response within macrophages.
Main Results:
- Overexpression of PE_PGRS45 enhanced bacterial viability and survival in macrophages.
- MS_PE_PGRS45 reduced pro-inflammatory cytokine secretion (IL-1β, IL-6, IL-12p40, TNF-α).
- MS_PE_PGRS45 increased IL-10 expression and inhibited macrophage apoptosis, promoting bacterial survival.
Conclusions:
- PE_PGRS45 is a virulence factor contributing to mycobacterial pathogenesis.
- PE_PGRS45 actively modulates host macrophage immune responses to facilitate bacterial survival.
- Understanding PE_PGRS45 function offers insights into TB pathogenesis and potential therapeutic targets.
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