@article {69755, title = {Quantitative Profiling pH Heterogeneity of Acidic Endolysosomal Compartments using Fluorescence Lifetime Imaging Microscopy.}, journal = {Mol Biol Cell}, year = {2025}, month = {2025 Jan 29}, pages = {mbcE23060220}, abstract = {

The endo-lysosomal system plays a crucial role in maintaining cellular homeostasis and promoting organism fitness. The pH of its acidic compartments is a crucial parameter for proper function, and it is dynamically influenced by both intracellular and environmental factors. Here, we present a method based on fluorescence lifetime imaging microscopy (FLIM) for quantitatively analyzing the pH profiles of acidic endolysosomal compartments in diverse types of primary mammalian cells and in live organism . This FLIM-based method exhibits high sensitivity in resolving subtle pH differences, thereby revealing heterogeneity within a cell and across cell types. This method enables rapid measurement of pH changes in the acidic endolysosomal system in response to various environmental stimuli. Furthermore, the fast FLIM measurement of pH-sensitive dyes circumvents the need for transgenic reporters and mitigates potential confounding factors associated with varying dye concentrations or excitation light intensity. This FLIM approach offers absolute pH quantification and highlights the significance of pH heterogeneity and dynamics, offering a valuable tool for investigating lysosomal functions and their regulation in various physiological and pathological contexts.

}, issn = {1939-4586}, doi = {10.1091/mbc.E23-06-0220}, author = {Deng, Dinghuan and Guan, Youchen and Mutlu, Ayse Sena and Wang, Baiping and Gao, Shihong Max and Zheng, Hui and Wang, Meng C} } @article {69702, title = {Structural dynamics and binding of Caenorhabditis elegans lifespan-extending lipid binding protein-3 to polyunsaturated fatty acids.}, journal = {Protein Sci}, volume = {34}, year = {2025}, month = {2025 Jan 01}, pages = {e5249}, abstract = {

Intracellular lipid binding proteins (iLBPs) play crucial roles in lipid transport and cellular metabolism across the animal kingdom. Recently, a fat-to-neuron axis was described in Caenorhabditis elegans, in which lysosomal activity in the fat liberates polyunsaturated fatty acids (PUFAs) that signal to neurons and extend lifespan with durable fecundity. In this study, we investigate the structure and binding mechanisms of a lifespan-extending lipid chaperone, lipid binding protein-3 (LBP-3), which shuttles dihomo-γ-linolenic (DGLA) acid from intestinal fat to neurons. We present the first high-resolution crystal structure of LBP-3, which reveals a classic iLBP fold with an unexpected and unique homodimeric arrangement via interstrand interactions that is incompatible with ligand binding. We identify key ionic interactions that mediate DGLA binding within the lipid binding pocket. Molecular dynamics simulations further elucidate LBP-3{\textquoteright}s preferential binding to DGLA due to its rotational freedom and access to favorable binding conformations compared to other 20-carbon PUFAs. We also propose that LBP-3 dimerization may be a unique regulatory mechanism for lipid chaperones.

}, keywords = {Animals, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Crystallography, X-Ray, Fatty Acid-Binding Proteins, Fatty Acids, Unsaturated, Molecular Dynamics Simulation, Protein Binding}, issn = {1469-896X}, doi = {10.1002/pro.5249}, url = {https://doi.org/10.1002/pro.5249}, author = {Cuevas, Andr{\'e} R and Tillman, Matthew C and Wang, Meng C and Ortlund, Eric A} } @article {69913, title = {Unlocking in vivo metabolic insights with vibrational microscopy.}, journal = {Nat Methods}, volume = {22}, year = {2025}, month = {2025 May 13}, pages = {886-889}, issn = {1548-7105}, doi = {10.1038/s41592-025-02616-3}, url = {https://doi.org/10.1038/s41592-025-02616-3}, author = {Chen, Tao and Savini, Marzia and Wang, Meng C} } @article {69914, title = {Unlocking in vivo metabolic insights with vibrational microscopy.}, journal = {Nat Methods}, volume = {22}, year = {2025}, month = {2025 May 13}, pages = {886-889}, abstract = {

No abstract available.

}, issn = {1548-7105}, doi = {10.1038/s41592-025-02616-3}, url = {https://doi.org/10.1038/s41592-025-02616-3}, author = {Chen, Tao and Savini, Marzia and Wang, Meng C} } @article {69482, title = {Aging atlas reveals cell-type-specific effects of pro-longevity strategies.}, journal = {Nat Aging}, year = {2024}, month = {2024 May 30}, abstract = {

Organismal aging involves functional declines in both somatic and reproductive tissues. Multiple strategies have been discovered to extend lifespan across species. However, how age-related molecular changes differ among various tissues and how those lifespan-extending strategies slow tissue aging in distinct manners remain unclear. Here we generated the transcriptomic Cell Atlas of Worm Aging (CAWA, http://mengwanglab.org/atlas ) of wild-type and long-lived strains. We discovered cell-specific, age-related molecular and functional signatures across all somatic and germ cell types. We developed transcriptomic aging clocks for different tissues and quantitatively determined how three different pro-longevity strategies slow tissue aging distinctively. Furthermore, through genome-wide profiling of alternative polyadenylation (APA) events in different tissues, we discovered cell-type-specific APA changes during aging and revealed how these changes are differentially affected by the pro-longevity strategies. Together, this study offers fundamental molecular insights into both somatic and reproductive aging and provides a valuable resource for in-depth understanding of the diversity of pro-longevity mechanisms.

}, issn = {2662-8465}, doi = {10.1038/s43587-024-00631-1}, author = {Gao, Shihong Max and Qi, Yanyan and Zhang, Qinghao and Guan, Youchen and Lee, Yi-Tang and Ding, Lang and Wang, Lihua and Mohammed, Aaron S and Li, Hongjie and Fu, Yusi and Wang, Meng C} } @article {69446, title = {Bacteria-organelle communication in physiology and disease}, journal = {J Cell Biol}, volume = {223}, year = {2024}, month = {2024 May 15}, abstract = {

Bacteria, omnipresent in our environment and coexisting within our body, exert dual beneficial and pathogenic influences. These microorganisms engage in intricate interactions with the human body, impacting both human health and disease. Simultaneously, certain organelles within our cells share an evolutionary relationship with bacteria, particularly mitochondria, best known for their energy production role and their dynamic interaction with each other and other organelles. In recent years, communication between bacteria and mitochondria has emerged as a new mechanism for regulating the host{\textquoteright}s physiology and pathology. In this review, we delve into the dynamic communications between bacteria and host mitochondria, shedding light on their collaborative regulation of host immune response, metabolism, aging, and longevity. Additionally, we discuss bacterial interactions with other organelles, including chloroplasts, lysosomes, and the endoplasmic reticulum (ER).

}, keywords = {Animals, Bacteria, Endoplasmic Reticulum, Host-Pathogen Interactions, Humans, Lysosomes, Mitochondria, Organelles}, issn = {1540-8140}, doi = {10.1083/jcb.202310134}, author = {Lee, Yi-Tang and Senturk, Mumine and Guan, Youchen and Wang, Meng C} } @article {69140, title = {Cutting through stress.}, journal = {Nature Metabolism}, year = {2024}, month = {2024 Jan 02}, issn = {2522-5812}, doi = {10.1038/s42255-023-00946-0}, author = {Jasper, Luis A and Wang, Meng C} } @article {69649, title = {FITM2 deficiency results in ER lipid accumulation, ER stress, and reduced apolipoprotein B lipidation and VLDL triglyceride secretion in vitro and in mouse liver.}, journal = {Mol Metab}, year = {2024}, month = {2024 Oct 18}, pages = {102048}, abstract = {

OBJECTIVES: Triglycerides (TGs) associate with apolipoprotein B100 (apoB100) to form very low density lipoproteins (VLDLs) in the liver. The repertoire of factors that facilitate this association is incompletely understood. FITM2, an integral endoplasmic reticulum (ER) protein, was originally discovered as a factor participating in cytosolic lipid droplet (LD) biogenesis in tissues that do not form VLDL. We hypothesized that in the liver, in addition to promoting cytosolic LD formation, FITM2 would also transfer TG from its site of synthesis in the ER membrane to nascent VLDL particles within the ER lumen.

METHODS: Experiments were conducted using a rat hepatic cell line (McArdle-RH7777, or McA cells), an established model of mammalian lipoprotein metabolism, and mice. FITM2 expression was reduced using siRNA in cells and by liver specific cre-recombinase mediated deletion of the Fitm2 gene in mice. Effects of FITM2 deficiency on VLDL assembly and secretion in\ vitro and in\ vivo were measured by multiple methods, including density gradient ultracentrifugation, chromatography, mass spectrometry, stimulated Raman scattering (SRS) microscopy, sub-cellular fractionation, immunoprecipitation, immunofluorescence, and electron microscopy.

MAIN FINDINGS: 1) FITM2-deficient hepatic cells in\ vitro and in\ vivo secrete TG-depleted VLDL particles, but the number of particles is unchanged compared to controls; 2) FITM2 deficiency in mice on a high fat diet (HFD) results in decreased plasma TG levels. The number of apoB100-containing lipoproteins remains similar, but shift from VLDL to low density lipoprotein (LDL) density; 3) Both in\ vitro and in\ vivo, when TG synthesis is stimulated and FITM2 is deficient, TG accumulates in the ER, and despite its availability this pool is unable to fully lipidate apoB100 particles; 4) FITM2 deficiency disrupts ER morphology and results in ER stress.

PRINCIPAL CONCLUSIONS: The results suggest that FITM2 contributes to VLDL lipidation, especially when newly synthesized hepatic TG is in abundance. In addition to its fundamental importance in VLDL assembly, the results also suggest that under dysmetabolic conditions, FITM2 may be an important factor in the partitioning of TG between cytosolic LDs and VLDL particles.

}, issn = {2212-8778}, doi = {10.1016/j.molmet.2024.102048}, url = {https://doi.org/10.1016/j.molmet.2024.102048}, author = {Wang, Haizhen and Nikain, Cyrus and Fortounas, Konstantinos I and Amengual, Jaime and Tufanli, Ozlem and La Forest, Maxwell and Yu, Yong and Wang, Meng C and Watts, Russell and Lehner, Richard and Qiu, Yunping and Cai, Min and Kurland, Irwin J and Goldberg, Ira J and Rajan, Sujith and Hussain, M Mahmood and Brodsky, Jeffrey L and Fisher, Edward A} } @article {69643, title = {IRE1α silences dsRNA to prevent taxane-induced pyroptosis in triple-negative breast cancer.}, journal = {Cell}, year = {2024}, month = {2024 Oct 14}, abstract = {

Chemotherapy is often combined with immune checkpoint inhibitor (ICIs) to enhance immunotherapy responses. Despite the approval of chemo-immunotherapy in multiple human cancers, many immunologically cold tumors remain unresponsive. The mechanisms determining the immunogenicity of chemotherapy are elusive. Here, we identify the ER stress sensor IRE1α as a critical checkpoint that restricts the immunostimulatory effects of taxane chemotherapy and prevents the innate immune recognition of immunologically cold triple-negative breast cancer (TNBC). IRE1α RNase silences taxane-induced double-stranded RNA (dsRNA) through regulated IRE1-dependent decay (RIDD) to prevent NLRP3 inflammasome-dependent pyroptosis. Inhibition of IRE1α in Trp53 TNBC allows taxane to induce extensive dsRNAs that are sensed by ZBP1, which in turn activates NLRP3-GSDMD-mediated pyroptosis. Consequently, IRE1α RNase inhibitor plus taxane converts PD-L1-negative, ICI-unresponsive TNBC tumors into PD-L1 immunogenic tumors that are hyper-sensitive to ICI. We reveal IRE1α as a cancer cell defense mechanism that prevents taxane-induced danger signal accumulation and pyroptotic cell death.

}, issn = {1097-4172}, doi = {10.1016/j.cell.2024.09.032}, url = {https://doi.org/10.1016/j.cell.2024.09.032}, author = {Xu, Longyong and Peng, Fanglue and Luo, Qin and Ding, Yao and Yuan, Fei and Zheng, Liting and He, Wei and Zhang, Sophie S and Fu, Xin and Liu, Jin and Mutlu, Ayse Sena and Wang, Shuyue and Nehring, Ralf Bernd and Li, Xingyu and Tang, Qianzi and Li, Catherine and Lv, Xiangdong and Dobrolecki, Lacey E and Zhang, Weijie and Han, Dong and Zhao, Na and Jaehnig, Eric and Wang, Jingyi and Wu, Weiche and Graham, Davis A and Li, Yumei and Chen, Rui and Peng, Weiyi and Chen, Yiwen and Catic, Andre and Zhang, Zhibin and Zhang, Bing and Mustoe, Anthony M and Koong, Albert C and Miles, George and Lewis, Michael T and Wang, Meng C and Rosenberg, Susan M and O{\textquoteright}Malley, Bert W and Westbrook, Thomas F and Xu, Han and Zhang, Xiang H-F and Osborne, C Kent and Li, Jin Billy and Ellis, Matthew J and Rimawi, Mothaffar F and Rosen, Jeffrey M and Chen, Xi} } @article {68998, title = {Mitochondrial GTP metabolism controls reproductive aging in C.~elegans.}, journal = {Developmental Cell}, year = {2023}, month = {2023 Sep 07}, abstract = {

Healthy mitochondria are critical for reproduction. During aging, both reproductive fitness and mitochondrial homeostasis decline. Mitochondrial metabolism and dynamics are key factors in supporting mitochondrial homeostasis. However, how they are coupled to control reproductive health remains unclear. We report that mitochondrial GTP (mtGTP) metabolism acts through mitochondrial dynamics factors to regulate reproductive aging. We discovered that germline-only inactivation of GTP- but not ATP-specific succinyl-CoA synthetase (SCS) promotes reproductive longevity in Caenorhabditis elegans. We further identified an age-associated increase in mitochondrial clustering surrounding oocyte nuclei, which is attenuated by GTP-specific SCS inactivation. Germline-only induction of mitochondrial fission factors sufficiently promotes mitochondrial dispersion and reproductive longevity. Moreover, we discovered that bacterial inputs affect mtGTP levels and dynamics factors to modulate reproductive aging. These results demonstrate the significance of mtGTP metabolism in regulating oocyte mitochondrial homeostasis and reproductive longevity and identify mitochondrial fission induction as an effective strategy to improve reproductive health.

}, issn = {1878-1551}, doi = {10.1016/j.devcel.2023.08.019}, author = {Lee, Yi-Tang and Savini, Marzia and Chen, Tao and Yang, Jin and Zhao, Qian and Ding, Lang and Gao, Shihong Max and Senturk, Mumine and Sowa, Jessica N and Wang, Jue D and Wang, Meng C} } @article {69103, title = {Mitochondrial GTP metabolism controls reproductive aging in C.~elegans.}, journal = {Developmental Cell}, volume = {58}, year = {2023}, month = {2023 Dec 04}, pages = {2718-2731.e7}, abstract = {

Healthy mitochondria are critical for reproduction. During aging, both reproductive fitness and mitochondrial homeostasis decline. Mitochondrial metabolism and dynamics are key factors in supporting mitochondrial homeostasis. However, how they are coupled to control reproductive health remains unclear. We report that mitochondrial GTP (mtGTP) metabolism acts through mitochondrial dynamics factors to regulate reproductive aging. We discovered that germline-only inactivation of GTP- but not ATP-specific succinyl-CoA synthetase (SCS) promotes reproductive longevity in Caenorhabditis elegans. We further identified an age-associated increase in mitochondrial clustering surrounding oocyte nuclei, which is attenuated by GTP-specific SCS inactivation. Germline-only induction of mitochondrial fission factors sufficiently promotes mitochondrial dispersion and reproductive longevity. Moreover, we discovered that bacterial inputs affect mtGTP levels and dynamics factors to modulate reproductive aging. These results demonstrate the significance of mtGTP metabolism in regulating oocyte mitochondrial homeostasis and reproductive longevity and identify mitochondrial fission induction as an effective strategy to improve reproductive health.

}, keywords = {Aging, Animals, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Guanosine Triphosphate, Longevity, Mitochondria, Mitochondrial Dynamics, Reproduction}, issn = {1878-1551}, doi = {10.1016/j.devcel.2023.08.019}, author = {Lee, Yi-Tang and Savini, Marzia and Chen, Tao and Yang, Jin and Zhao, Qian and Ding, Lang and Gao, Shihong Max and Senturk, Mumine and Sowa, Jessica N and Wang, Jue D and Wang, Meng C} }