Decoding Drug Tolerance: Insights into the Rv0274 Gene's Role in Isoniazid Tolerance

Zhen Gong^1*Min Li²Yun Wang²Xiaohong Xiang³Qiming Li⁴Zhou Liu⁵Wenwen Chu²Naifang Ye²Qiang Zhou^2*

• ¹Karolinska Institutet (KI), Solna, Sweden
• ²Second Affiliated Hospital of Anhui Medical University, Hefei, China
• ³Chongqing Medical and Pharmaceutical College, Chongqing, China
• ⁴The First Affiliated Hospital of Henan University, Kaifeng, China
• ⁵Anhui Chest Hospital, Hefei, China

Isoniazid is a widely utilized pharmacological agent in the treatment of pulmonary tuberculosis, and the elucidation of its tolerance mechanisms is of significant academic interest. It is postulated that the Rv0274 gene in Mycobacterium tuberculosis, which is presumed to belong to the aldehyde dehydrogenase family, may contribute to the development of tolerance to isoniazid. In this study, we employed Mycobacterium smegmatis as a model organism to investigate this hypothesis. We conducted a knockout of its homologous gene, MSMEG_0608, and performed a series of experiments including drug susceptibility tests, growth curve analyses, biofilm formation assays, transcriptomics, and RT-qPCR. Additionally, we complemented Rv0274 and knocked down MSMEG_0606 to further substantiate our findings. The results unequivocally demonstrated that MSMEG_0608 is integral to isoniazid tolerance. Further analyses suggest that Rv0274 (MSMEG_0608) may exert a negative regulatory effect on the expression of genes associated with Rv0273c (MSMEG_0606), thereby influencing the expression of the inhA gene and contributing to isoniazid tolerance. This study offers preliminary insights into the mechanisms underlying INH tolerance in mycobacteria, providing a theoretical framework for future investigations into drug tolerance in Mycobacterium tuberculosis.