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Resistance to antimicrobials in Mycobacterium tuberculosis: structural, biophysical and biochemical analysis of missense mutations

Grant number: 22/12234-5
Support Opportunities:Regular Research Grants
Duration: March 01, 2023 - February 28, 2025
Field of knowledge:Biological Sciences - Biochemistry - Biochemistry of Microorganisms
Principal Investigator:Marcio Vinicius Bertacine Dias
Grantee:Marcio Vinicius Bertacine Dias
Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil


Tuberculosis is one of the major infectious diseases that afflict humankind, which causes the death of about a million people worldwide. Because of the intensive use of antimicrobials in the treatment of this disease, resistance is an extremely worrisome feature and that significantly worsens its therapeutic interventions. Bacterial resistance to the main in-use antimicrobials, particularly isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PZA) is constantly reported in Mycobacterium tuberculosis, which causes the need to use other antimicrobials which are more toxic and lesser effective for the disease control. Specifically, as for INH as PZA, the resistance is mainly associated with genes involved with its activation or in their inhibition targets. Therefore, mutations in the Catalase/Peroxidase KatG, which catalysis the formation of NAD-INH adduct and the enzyme enoyl ACP reductase, InhA, are often reported in clinical isolates resistant to INH. The same occurs for the resistance to PZA, in which a number of mutations in the gene that encodes for the enzyme PcnA, which converts PZA to pyrazinoic acid (POA) and the enzyme aspartate decarboxylase (PanD), which is inhibited by this molecule, also is frequently reported. The enzymes which are considered targets of the activated prodrugs INH and PZA are essential to the survival of M. tuberculosis and, therefore, the mutations usually occur either in the promoter or in the encoding region of their genes, being predominantly missense. Although there are a number of biochemical, biophysical and structural studies for a reduced number of missense mutants for the enzymes InhA and PanD, the number of reported mutations in the literature is large, which limits the understanding of the effective molecular mechanisms involved in the resistance against these antimicrobials. In this project, we aim to perform a deep study of biophysical and biochemical in a larger number of missense mutations for the encoding regions of inhA and panD that were not satisfactorily studied. The structural, biochemical, and biophysical analysis of these mutant proteins may reveal the molecular basis involved in the resistance to INH and PZA and, consequently the proposition of mechanisms still not reported in the literature. Furthermore, the understanding of such mutations can significantly contribute to the development of novel molecules that overcome these resistances or effectively contribute to a more personalized therapy based on cases of infections by resistant and multi-resistant strains. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
ROSSINI, NICOLAS DE OLIVEIRA; DIAS, MARCIO VINICIUS BERTACINE. Mutations and insights into the molecular mechanisms of resistance of Mycobacterium tuberculosis to first-line drugs. GENETICS AND MOLECULAR BIOLOGY, v. 46, n. 1, p. 17-pg., . (22/12234-5, 20/03850-9, 19/17037-0)
NICOLAS DE OLIVEIRA ROSSINI; MARCIO VINICIUS BERTACINE DIAS. Mutations and insights into the molecular mechanisms of resistance of Mycobacterium tuberculosis to first-line. GENETICS AND MOLECULAR BIOLOGY, v. 46, n. 1, . (22/12234-5, 19/17037-0, 20/03850-9)

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