Shared characteristics between Mycobacterium tuberculosis and fungi contribute to virulence

Area of Science:

• Immunology
• Microbiology
• Evolutionary Biology

Background:

• Tuberculosis, caused by Mycobacterium tuberculosis, remains a significant global health burden.
• Increasing human population density correlates with the emergence of new, more virulent M. tuberculosis strains.
• These emergent strains exhibit immune evasion strategies, shifting host responses from Th1 to Th2 bias, similar to pathogenic fungi.

Purpose of the Study:

• To investigate the evolutionary relationship between emergent virulent M. tuberculosis strains and pathogenic fungi.
• To identify conserved traits that facilitate immune evasion and dissemination in both M. tuberculosis and fungi.
• To propose a hypothesis of convergent evolution driving the virulence of emergent M. tuberculosis strains.

Main Methods:

• Review of scientific literature from M. tuberculosis and pathogenic fungi research fields.
• Comparative analysis of infection sites, metabolic features, cell surface molecules, and immune receptor engagement.
• Examination of granuloma formation capabilities in both pathogen types.

Main Results:

• Emergent M. tuberculosis strains share multiple characteristics with pathogenic fungi, including immune modulation towards a Th2 response.
• Commonalities extend to infection site tropism, metabolic strategies, cell surface molecule expression, and granuloma formation.
• These shared traits suggest a functional convergence between M. tuberculosis and fungi.

Conclusions:

• Emergent virulent M. tuberculosis strains are undergoing convergent evolution with pathogenic fungi.
• This evolution involves the increased prominence of ancestral traits that enhance immune evasion and dissemination.
• Understanding these conserved mechanisms is crucial for developing novel therapeutic strategies against tuberculosis.