@article {161133, title = {Bioenergetic reprogramming of macrophages reduces drug tolerance in Mycobacterium tuberculosis.}, journal = {Nat Commun}, volume = {16}, year = {2025}, month = {2025 Oct 23}, pages = {9370}, abstract = {

Effective clearance of Mycobacterium tuberculosis (Mtb) requires targeting drug-tolerant populations within host macrophages. Here, we show that macrophage metabolic states govern redox heterogeneity and drug response in intracellular Mtb. Using a redox-sensitive fluorescent reporter (Mrx1-roGFP2), flow cytometry, and transcriptomics, we found that macrophages with high oxidative phosphorylation (OXPHOS) and low glycolysis harbor reductive, drug-tolerant Mtb, whereas glycolytically active macrophages generate mitochondrial ROS via reverse electron transport, imposing oxidative stress on Mtb and enhancing drug efficacy. Computational and genetic analyses identified NRF2 as a key regulator linking host metabolism to bacterial redox state and drug tolerance. Pharmacological reprogramming of macrophages with the FDA-approved drug meclizine (MEC) shifted metabolism towards glycolysis, suppressed redox heterogeneity, and reduced Mtb drug tolerance in macrophages and mice. MEC exhibited no adverse interactions with frontline anti-TB drugs. These findings demonstrate the therapeutic potential of host metabolic reprogramming to overcome Mtb drug tolerance.

}, keywords = {Animals, Antitubercular Agents, Drug Tolerance, Energy Metabolism, Female, Glycolysis, Humans, Macrophages, Mice, Mice, Inbred C57BL, Mitochondria, Mycobacterium tuberculosis, NF-E2-Related Factor 2, Oxidation-Reduction, Oxidative Phosphorylation, Oxidative Stress, Reactive Oxygen Species, Tuberculosis}, issn = {2041-1723}, doi = {10.1038/s41467-025-64407-w}, author = {Yadav, Vikas and Sahoo, Sarthak and Malhotra, Nitish and Mishra, Richa and Sreedharan, Sreesa and Rajmani, Raju S and Shanmugam, Siva and Shandil, Radha K and Narayanan, Shridhar and Thacker, Vivek V and Laxman, Sunil and Jolly, Mohit Kumar and Seshasayee, Aswin Sai Narain and Singh, Amit} } @article {157492, title = {M. tuberculosis surface sulfoglycolipid SL-1 activates the mechanosensitive channel TRPV4 to enhance lysosomal biogenesis and exocytosis in macrophages}, journal = {Mol Biol Cell}, volume = {36}, year = {2025}, month = {2025 Jun 01}, pages = {ar76}, abstract = {

Intracellular pathogens manipulate host cellular pathways to ensure their survival. (Mtb) disrupts phagosomal trafficking to prevent fusion with lysosomes. Beyond this localized effect, Mtb globally remodels the host lysosomal system, predominantly through its virulence-associated surface lipid, sulfolipid-1 (SL-1). SL-1 enhances lysosomal biogenesis via the mTORC1-TFEB axis; however, the upstream mediators remain unknown. Here, we show that SL-1 induces calcium influx into macrophages and identify the mechanosensitive calcium channel transient receptor potential vanilloid subtype 4 (TRPV4) as a crucial upstream mediator of SL-1-induced lysosomal remodeling. TRPV4 influences multiple aspects of lysosomal function, including biogenesis, acidification, enzymatic activity, phagosome maturation, and lysosomal exocytosis. These effects are recapitulated during Mtb infection, underscoring the relevance of SL-1- and TRPV4-dependent lysosomal remodeling in an infection context. TRPV4 expression is upregulated during Mtb infection and partially localizes to both lysosomes and the Mtb-containing vacuole. Remarkably, TRPV4 activation, independent of SL-1, is sufficient to enhance lysosomal biogenesis, identifying TRPV4 as a key regulator of lysosomal homeostasis. Together, these findings uncover a novel mechanism of lysosomal remodeling driven by a pathogen lipid virulence factor and reveal a previously unrecognized role for TRPV4 in modulating lysosomal homeostasis in macrophages.

}, keywords = {Animals, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors, Calcium, Exocytosis, Glycolipids, Humans, Lysosomes, Macrophages, Mice, Mice, Inbred C57BL, Mycobacterium tuberculosis, Phagosomes, TRPV Cation Channels}, issn = {1939-4586}, doi = {10.1091/mbc.E24-12-0560}, url = {https://www.molbiolcell.org/doi/10.1091/mbc.E24-12-0560?url_ver=Z39.88-2003\&rfr_id=ori:rid:crossref.org\&rfr_dat=cr_pub\%20\%200pubmed}, author = {Umar, Ibrahim and Gulzar, Shah-E-Jahan and Sundaramurthy, Varadharajan} } @article {149383, title = {CDS2 expression regulates de novo phosphatidic acid synthesis.}, journal = {Biochem J}, volume = {481}, year = {2024}, month = {2024 Oct 16}, pages = {1449-1473}, abstract = {

CDS enzymes (CDS1 and 2 in mammals) convert phosphatidic acid (PA) to CDP-DG, an essential intermediate in the de novo synthesis of PI. Genetic deletion of CDS2 in primary mouse macrophages resulted in only modest changes in the steady-state levels of major phospholipid species, including PI, but substantial increases in several species of PA, CDP-DG, DG and TG. Stable isotope labelling experiments employing both 13C6- and 13C6D7-glucose revealed loss of CDS2 resulted in a minimal reduction in the rate of de novo PI synthesis but a substantial increase in the rate of de novo PA synthesis from G3P, derived from DHAP via glycolysis. This increased synthesis of PA provides a potential explanation for normal basal PI synthesis in the face of reduced CDS capacity (via increased provision of substrate to CDS1) and increased synthesis of DG and TG (via increased provision of substrate to LIPINs). However, under conditions of sustained GPCR-stimulation of PLC, CDS2-deficient macrophages were unable to maintain enhanced rates of PI synthesis via the {\textquoteright}PI cycle{\textquoteright}, leading to a substantial loss of PI. CDS2-deficient macrophages also exhibited significant defects in calcium homeostasis which were unrelated to the activation of PLC and thus probably an indirect effect of increased basal PA. These experiments reveal that an important homeostatic response in mammalian cells to a reduction in CDS capacity is increased de novo synthesis of PA, likely related to maintaining normal levels of PI, and provides a new interpretation of previous work describing pleiotropic effects of CDS2 deletion on lipid metabolism/signalling.

}, keywords = {Animals, Calcium, Diacylglycerol Cholinephosphotransferase, Macrophages, Mice, Mice, Inbred C57BL, Mice, Knockout, Phosphatidic Acids}, issn = {1470-8728}, doi = {10.1042/BCJ20240456}, author = {Collins, Daniel M and Janardan, Vishnu and Barneda, David and Anderson, Karen E and Niewczas, Izabella and Taylor, Diane and Qiu, Danye and Jessen, Henning J and Lopez-Clavijo, Andrea F and Walker, Simon and Raghu, Padinjat and Clark, Jonathan and Stephens, Len R and Hawkins, Phillip T} } @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 = {

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).

}, 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} }