Fig. 5. H₂S induces transcriptome remodeling and mitigates oxidative stress in Mtb.

RNA-seq-based gene expression analysis shows induction of the Mtb a copper, b sulfur and c Dos regulons following exposure to 25 µM GYY4137 for 1 h. Genes exhibiting ≥1.5-fold (+/–) change in expression compared to the expression in untreated cells were considered differentially regulated (n = 3 independent biological replicates per group). d Proposed model detailing the relationship between H₂S and induction of the Mtb copper regulon. Exposure to H₂S leads to the formation of copper sulfides, which relieve repression of CsoR leading to the export of copper via the cso. e Representative results of qRT-PCR analysis of key dormancy regulon genes following 1 h exposure to 25 µM GYY4137 in Mtb H37Rv, ΔdosS, ΔdosT and ΔdosST (n = 5 independent biological replicates per Mtb strain). Fold change in gene expression following addition of GYY4137 is shown. f Survival of Mtb cells (% CFU) exposed to metronidazole (MN) alone, or MN and 25 µM GYY4137. g Recovery profile of Mtb cells following prolonged hypoxia (8 weeks). Prior to hypoxia, one group of cells received 25 µM GYY4137. h Mean CFUs following 1 week of recovery following prolonged hypoxia. (g) and (h) represent pooled data from two or more independent experiments (n = 4). i Percentage survival (CFU) of 25 µM GYY4137-treated Mtb cells following exposure to oxidative stressors CHP and MND (0.5 mM for 6 h) relative to untreated cells. j Percent of dihydroethidium (DHE)-positive ROS-producing Mtb cells following exposure to 10−50 µM GYY4137 (spent GYY4137 used as 0 µM control; n = 3 per group). CHP treatment (15 mM) was used as a positive control for detection of ROS-positive cells. Data in (f) and (i) are representative of two or more experiments. All data are shown as mean ± SD, except (e) (mean ± SEM). Data were analyzed using one-way ANOVA (e and j) with Sidak’s multiple comparisons test, or by two-way ANOVA with Sidak’s multiple comparisons test (f−h), or by unpaired parametric t test (i). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Source data are provided as a Source Data file.