Culture of Mycobacterium smegmatis in Different Carbon Sources to Induce In Vitro Cholesterol Consumption Leads to Alterations in the Host Cells after Infection: A Macrophage Proteomics Analysis.

Jaqueline Batista De Lima,Barbarella De Matos Macchi,Edilene Oliveira Da Silva,Chubert Bernardo Castro De Sena,Lana Patricia Da Silva Fonseca,Juliana Silva Cassoli,José Luiz Martins Do Nascimento,Agenor Valadares Santos,Rafael Borges Da Silva Valadares,Luciana Pereira Xavier

doi:10.3390/pathogens10060662

Abstract

During tuberculosis, Mycobacterium uses host macrophage cholesterol as a carbon and energy source. To mimic these conditions, Mycobacterium smegmatis can be cultured in minimal medium (MM) to induce cholesterol consumption in vitro. During cultivation, M. smegmatis consumes MM cholesterol and changes the accumulation of cell wall compounds, such as PIMs, LM, and LAM, which plays an important role in its pathogenicity. These changes lead to cell surface hydrophobicity modifications and H2O2 susceptibility. Furthermore, when M. smegmatis infects J774A.1 macrophages, it induces granuloma-like structure formation. The present study aims to assess macrophage molecular disturbances caused by M. smegmatis after cholesterol consumption, using proteomics analyses. Proteins that showed changes in expression levels were analyzed in silico using OmicsBox and String analysis to investigate the canonical pathways and functional networks involved in infection. Our results demonstrate that, after cholesterol consumption, M. smegmatis can induce deregulation of protein expression in macrophages. Many of these proteins are related to cytoskeleton remodeling, immune response, the ubiquitination pathway, mRNA processing, and immunometabolism. The identification of these proteins sheds light on the biochemical pathways involved in the mechanisms of action of mycobacteria infection, and may suggest novel protein targets for the development of new and improved treatments.

Highlights

Tuberculosis (TB) is a communicable disease that is a major cause of ill health worldwide
Macrophage proteins were extracted at 12 after infection experiments: (1) M. smegmatis cultivated in complete medium Middlebrook 7H9 broth, groups
Macrophages without infection were used as a control g which is normally supplemented with glycerol (7H9 + Gly); (2) culture in MM with cholesterol

Summary

Introduction

Tuberculosis (TB) is a communicable disease that is a major cause of ill health worldwide. A quarter of the global population is infected with the causative agent, Mycobacterium tuberculosis (M. tuberculosis), and at risk of developing TB disease. TB is transmitted by aerosols in droplets containing the bacteria from an infected individual to a healthy individual. The improvement of knowledge regarding the host–pathogen interaction is one manner of overcoming obstacles to control TB. M. tuberculosis is a successful human pathogen that is able to grow and replicate within a host and its success as an infectious agent is due, in large, to its ability to persist in the macrophages [2]. The pathogenesis of tuberculosis is controlled by a complex interaction between the host immune system and survival strategies developed by M. tuberculosis [2]

Methods

Results

Conclusion