
@article {147303,
	title = {Intracellular peroxynitrite perturbs redox balance, bioenergetics, and Fe-S cluster homeostasis in Mycobacterium tuberculosis.},
	journal = {Redox Biol},
	volume = {75},
	year = {2024},
	month = {2024 Sep},
	pages = {103285},
	abstract = {<p>The ability of Mycobacterium tuberculosis (Mtb) to tolerate nitric oxide (NO) and superoxide (O) produced by phagocytes contributes to its success as a human pathogen. Recombination of NO and O generates peroxynitrite (ONOO), a potent oxidant produced inside activated macrophages causing lethality in diverse organisms. While the response of Mtb toward NO and O is well established, how Mtb responds to ONOO remains unclear. Filling this knowledge gap is important to understand the persistence mechanisms of Mtb during infection. We synthesized a series of compounds that generate both NO and O, which should combine to produce ONOO. From this library, we identified CJ067 that permeates Mtb to reliably enhance intracellular ONOO levels. CJ067-exposed Mtb strains, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) clinical isolates, exhibited dose-dependent, long-lasting oxidative stress and growth inhibition. In contrast, Mycobacterium smegmatis (Msm), a fast-growing, non-pathogenic mycobacterial species, maintained redox balance and growth in response to intracellular ONOO. RNA-sequencing with Mtb revealed that CJ067 induces antioxidant machinery, sulphur metabolism, metal homeostasis, and a 4Fe-4S cluster repair pathway (suf operon). CJ067 impaired the activity of the 4Fe-4S cluster-containing TCA cycle enzyme, aconitase, and diminished bioenergetics of Mtb. Work with Mtb strains defective in SUF and IscS involved in Fe-S cluster biogenesis pathways showed that both systems cooperatively protect Mtb from intracellular ONOO in vitro and inducible nitric oxide synthase (iNOS)-dependent growth inhibition during macrophage infection. Thus, Mtb is uniquely sensitive to intracellular ONOO and targeting Fe-S cluster homeostasis is expected to promote iNOS-dependent host immunity against tuberculosis (TB).</p>
},
	keywords = {Energy Metabolism, Homeostasis, Humans, Iron-Sulfur Proteins, Macrophages, Mycobacterium smegmatis, Mycobacterium tuberculosis, Nitric Oxide, Oxidation-Reduction, Oxidative Stress, Peroxynitrous Acid, Superoxides, Tuberculosis},
	issn = {2213-2317},
	doi = {10.1016/j.redox.2024.103285},
	author = {Dewan, Arshiya and Jain, Charu and Das, Mayashree and Tripathi, Ashutosh and Sharma, Ajay Kumar and Singh, Harshit and Malhotra, Nitish and Seshasayee, Aswin Sai Narain and Chakrapani, Harinath and Singh, Amit}
}
@article {98081,
	title = {Mycobacterium tuberculosis SufR responds to nitric oxide via its 4Fe-4S cluster and regulates Fe-S cluster biogenesis for persistence in mice.},
	journal = {Redox Biol},
	volume = {46},
	year = {2021},
	month = {2021 Jul 02},
	pages = {102062},
	abstract = {<p>The persistence of Mycobacterium tuberculosis (Mtb) is a major problem in managing tuberculosis (TB). Host-generated nitric oxide (NO) is perceived as one of the signals by Mtb to reprogram metabolism and respiration for persistence. However, the mechanisms involved in NO sensing and reorganizing Mtb{\textquoteright}s physiology are not fully understood. Since NO damages iron-sulfur (Fe-S) clusters of essential enzymes, the mechanism(s) involved in regulating Fe-S cluster biogenesis could help Mtb persist in host tissues. Here, we show that a transcription factor SufR (Rv1460) senses NO via its 4Fe-4S cluster and promotes persistence of Mtb by mobilizing the Fe-S cluster biogenesis system; suf operon (Rv1460-Rv1466). Analysis of anaerobically purified SufR by UV-visible spectroscopy, circular dichroism, and iron-sulfide estimation confirms the presence of a 4Fe-4S cluster. Atmospheric O and HO gradually degrade the 4Fe-4S cluster of SufR. Furthermore, electron paramagnetic resonance (EPR) analysis demonstrates that NO directly targets SufR 4Fe-4S cluster by forming a protein-bound dinitrosyl-iron-dithiol complex. DNase I footprinting, gel-shift, and in vitro transcription assays confirm that SufR directly regulates the expression of the suf operon in response to NO. Consistent with this, RNA-sequencing of MtbΔsufR demonstrates deregulation of the suf operon under NO stress. Strikingly, NO inflicted irreversible damage upon Fe-S clusters to exhaust respiratory and redox buffering capacity of MtbΔsufR. Lastly, MtbΔsufR failed to recover from a NO-induced non-growing state and displayed persistence defect inside immune-activated macrophages and murine lungs in a NO-dependent manner. Data suggest that SufR is a sensor of NO that supports persistence by reprogramming Fe-S cluster metabolism and bioenergetics.</p>
},
	issn = {2213-2317},
	doi = {10.1016/j.redox.2021.102062},
	author = {Anand, Kushi and Tripathi, Ashutosh and Shukla, Kaustubh and Malhotra, Nitish and Jamithireddy, Anil Kumar and Jha, Rajiv Kumar and Chaudhury, Susmit Narayan and Rajmani, Raju S and Ramesh, Arati and Nagaraja, Valakunja and Gopal, Balasubramanian and Nagaraju, Ganesh and Narain Seshayee, Aswin Sai and Singh, Amit}
}
