Comparative transcriptomic profiling of pyrazinamide resistance in Mycobacterium tuberculosis

Area of Science:

• Microbiology
• Genomics
• Drug Resistance

Background:

• Pyrazinamide (PZA) resistance in Mycobacterium tuberculosis (Mtb) is a major challenge in tuberculosis treatment.
• Mutations in the pncA gene are the primary cause of PZA resistance, but other transcriptional adaptations are not fully understood.

Purpose of the Study:

• To characterize the transcriptomic adaptations associated with PZA resistance in Mtb.
• To compare a PZA-resistant clinical strain (PZAR) with a drug-susceptible laboratory strain (H37Rv) under PZA treatment.

Main Methods:

• RNA sequencing was performed on a PZA-resistant clinical strain (with a pncA deletion) and a drug-susceptible laboratory strain (H37Rv).
• Differential gene expression analysis was conducted under treated and untreated conditions.
• Functional enrichment and network analyses were used to identify key pathways.

Main Results:

• Over 3,400 differentially expressed genes were identified, with significant enrichment in the resistant strain.
• Ribosomal machinery genes were upregulated in the resistant strain under PZA pressure.
• Downregulation of anti-TB drug targets and upregulation of efflux pump genes were observed.
• Network analysis highlighted modules involved in polyketide synthesis, PDIM synthesis, fatty acid metabolism, and ESX secretion.

Conclusions:

• The study identified mutation-associated and PZA-responsive transcriptomic signatures in Mtb.
• These signatures reveal adaptive pathways contributing to drug tolerance under PZA pressure.
• The findings provide a foundation for future research into Mtb drug resistance mechanisms and potential therapeutic strategies.