bims-celmim Biomed News
on Cellular and mitochondrial metabolism
Issue of 2025–01–19
nineteen papers selected by
Marc Segarra Mondejar
  1. In vivo itaconate tracing reveals degradation pathway and turnover kinetics.
  2. Targeting Asparagine Metabolism in Solid Tumors.
  3. Tumor-induced metabolic immunosuppression: Mechanisms and therapeutic targets.
  4. The systemic evolutionary theory of the origin of cancer (SETOC): an update.
  5. Lactylation fuels nucleotide biosynthesis and facilitates deuterium metabolic imaging of tumor proliferation in H3K27M-mutant gliomas.
  6. Live-cell metabolic analyzer protocol for measuring glucose and lactate metabolic changes in human cells.
  7. Spatially resolved rewiring of mitochondria-lipid droplet interactions in hepatic lipid homeostasis.
  8. Integrated RNA sequencing analysis and machine learning identifies a metabolism-related prognostic signature in clear cell renal cell carcinoma.
  9. IL-7 promotes integrated glucose and amino acid sensing during homeostatic CD4+ T cell proliferation.
  10. Autophagy regulator ATG5 preserves cerebellar function by safeguarding its glycolytic activity.
  11. MTHFD2 Enhances cMYC O-GlcNAcylation to Promote Sunitinib Resistance in Renal Cell Carcinoma.
  12. mTORC1 regulates the pyrimidine salvage pathway by controlling UCK2 turnover via the CTLH-WDR26 E3 ligase.
  13. Metabolic Profiling: A Perspective on the Current Status, Challenges, and Future Directions.
  14. Glutaminase-2 Expression Induces Metabolic Changes and Regulates Pyruvate Dehydrogenase Activity in Glioblastoma Cells.
  15. Multi-organelle imaging with dye combinations: targeting the ER, mitochondria, and plasma membrane.
  16. Glucosamine Inhibits the Proliferation of Hepatocellular Carcinoma Cells by Eliciting Apoptosis, Autophagy, and the Anti-Warburg Effect.
  17. Ultrafast multicellular calcium imaging of calcium spikes in mouse beta cells in tissue slices.
  18. SNARE-Mediated Membrane Fusion Probed Using a Synthetic Organelle in the Living Bacterium.
  19. Engineered hypoxia-responsive albumin nanoparticles mediating mitophagy regulation for cancer therapy.
  1. bioRxiv. 2025 Jan 02. pii: 2025.01.02.629617. [Epub ahead of print]
    In vivo itaconate tracing reveals degradation pathway and turnover kinetics.
    Hanna F Willenbockel, Alexander T Williams, Alfredo Lucas, Birte Dowerg, Pedro Cabrales, Christian M Metallo, Thekla Cordes.
      Itaconate is an immunomodulatory metabolite that alters mitochondrial metabolism and immune cell function. This organic acid is endogenously synthesized via tricarboxylic acid (TCA) metabolism downstream of TLR signaling. Itaconate-based treatment strategies are being explored to mitigate numerous inflammatory conditions. However, little is known about the turnover rate of itaconate in circulation, the kinetics of its degradation, and the broader consequences on metabolism. By combining mass spectrometry and in vivo 13 C itaconate tracing, we demonstrate that itaconate is rapidly eliminated from plasma, excreted via urine, and fuels TCA cycle metabolism specifically in the liver and kidneys. These studies further revealed that itaconate is converted into acetyl-CoA, mesaconate, and citramalate in mitochondria. Itaconate administration also influenced branched-chain amino acid metabolism and succinate levels, indicating a functional impact on succinate dehydrogenase (SDH) and methylmalonyl-CoA mutase (MUT) activity. Our findings uncovered a previously unknown aspect of the itaconate metabolism, highlighting its rapid catabolism in vivo that contrasts findings in cultured cells.
    DOI:  https://doi.org/10.1101/2025.01.02.629617
  2. Nutrients. 2025 Jan 03. pii: 179. [Epub ahead of print]17(1):
    Targeting Asparagine Metabolism in Solid Tumors.
    Keita Hanada, Kenji Kawada, Kazutaka Obama.
      Reprogramming of energy metabolism to support cellular growth is a "hallmark" of cancer, allowing cancer cells to balance the catabolic demands with the anabolic needs of producing the nucleotides, amino acids, and lipids necessary for tumor growth. Metabolic alterations, or "addiction", are promising therapeutic targets and the focus of many drug discovery programs. Asparagine metabolism has gained much attention in recent years as a novel target for cancer therapy. Asparagine is widely used in the production of other nutrients and plays an important role in cancer development. Nutritional inhibition therapy targeting asparagine has been used as an anticancer strategy and has shown success in the treatment of leukemia. However, in solid tumors, asparagine restriction alone does not provide ideal therapeutic efficacy. Tumor cells initiate reprogramming processes in response to asparagine deprivation. This review provides a comprehensive overview of asparagine metabolism in cancers. We highlight the physiological role of asparagine and current advances in improving survival and overcoming therapeutic resistance.
    Keywords:  asparagine metabolism; cancer; glutamine metabolism; metabolic adaptation
    DOI:  https://doi.org/10.3390/nu17010179
  3. Cell Rep. 2025 Jan 10. pii: S2211-1247(24)01557-2. [Epub ahead of print]44(1): 115206
    Tumor-induced metabolic immunosuppression: Mechanisms and therapeutic targets.
    Jean-Ehrland Ricci.
      Metabolic reprogramming in both immune and cancer cells plays a crucial role in the antitumor immune response. Recent studies indicate that cancer metabolism not only sustains carcinogenesis and survival via altered signaling but also modulates immune cell function. Metabolic crosstalk within the tumor microenvironment results in nutrient competition and acidosis, thereby hindering immune cell functionality. Interestingly, immune cells also undergo metabolic reprogramming that enables their proliferation, differentiation, and effector functions. This review highlights the regulation of antitumor immune responses through metabolic reprogramming in cancer and immune cells and explores therapeutic strategies that target these metabolic pathways in cancer immunotherapy, including using chimeric antigen receptor (CAR)-T cells. We discuss innovative combinations of immunotherapy, cellular therapies, and metabolic interventions that could optimize the efficacy of existing treatment protocols.
    Keywords:  CP: Cancer; CP: Metabolism; antitumor activity of immune cells; cancer; metabolism; therapeutic strategies; tumor microenvironment
    DOI:  https://doi.org/10.1016/j.celrep.2024.115206
  4. Mol Med. 2025 Jan 14. 31(1): 12
    The systemic evolutionary theory of the origin of cancer (SETOC): an update.
    Antonio Mazzocca, Giovanni Ferraro, Giovanni Misciagna.
      The Systemic Evolutionary Theory of the Origin of Cancer (SETOC) is a recently proposed theory founded on two primary principles: the cooperative and endosymbiotic process of cell evolution as described by Lynn Margulis, and the integration of complex systems operating in eukaryotic cells, which is a core concept in systems biology. The SETOC proposes that malignant transformation occurs when cells undergo a continuous adaptation process in response to long-term injuries, leading to tissue remodeling, chronic inflammation, fibrosis, and ultimately cancer. This process involves a maladaptive response, wherein the 'endosymbiotic contract' between the nuclear-cytoplasmic system (derived from the primordial archaeal cell) and the mitochondrial system (derived from the primordial α-proteobacterium) gradually breaks down. This ultimately leads to uncoordinated behaviors and functions in transformed cells. The decoupling of the two cellular subsystems causes transformed cells to acquire phenotypic characteristics analogous to those of unicellular organisms, as well as certain biological features of embryonic development that are normally suppressed. These adaptive changes enable cancer cells to survive in the harsh tumor microenvironment characterized by low oxygen concentrations, inadequate nutrients, increased catabolic waste, and increased acidity. De-endosymbiosis reprograms the sequential metabolic functions of glycolysis, the TCA cycle, and oxidative phosphorylation (OxPhos). This leads to increased lactate fermentation (Warburg effect), respiratory chain dysfunction, and TCA cycle reversal. Here, we present an updated version of the SETOC that incorporates the fundamental principles outlined by this theory and integrates the epistemological approach used to develop it.
    Keywords:  Archaea; Cancer theories; Endosymbiosis; Evolution; Mitochondria; Systems biology; Warburg effect
    DOI:  https://doi.org/10.1186/s10020-025-01069-w
  5. bioRxiv. 2025 Jan 03. pii: 2025.01.02.631150. [Epub ahead of print]
    Lactylation fuels nucleotide biosynthesis and facilitates deuterium metabolic imaging of tumor proliferation in H3K27M-mutant gliomas.
    Georgios Batsios, Céline Taglang, Suresh Udutha, Anne Marie Gillespie, Simon P Robinson, Timothy Phoenix, Sabine Mueller, Sriram Venneti, Carl Koschmann, Pavithra Viswanath.
      Oncogenes hyperactive lactate production, but the mechanisms by which lactate facilitates tumor growth are unclear. Here, we demonstrate that lactate is essential for nucleotide biosynthesis in pediatric diffuse midline gliomas (DMGs). The oncogenic histone H3K27M mutation upregulates phosphoglycerate kinase 1 (PGK1) and drives lactate production from [U- 13 C]-glucose in DMGs. Lactate activates the nucleoside diphosphate kinase NME1 via lactylation and promotes the synthesis of nucleoside triphosphates essential for tumor proliferation. Importantly, we show that this mechanistic link between glycolysis and nucleotide biosynthesis provides a unique opportunity for deuterium metabolic imaging of DMGs. Spatially mapping 2 H-lactate production from [6,6- 2 H]-glucose allows visualization of the metabolically active tumor lesion and provides an early readout of response to standard-of-care radiation and targeted therapy that precedes extended survival and reflects pharmacodynamic alterations at the tissue level in preclinical DMG models in vivo at clinical field strength (3T). In essence, we have identified an H3K27M-lactate-NME1 axis that promotes DMG proliferation and facilitates non-invasive metabolic imaging of DMGs.
    STATEMENT OF SIGNIFICANCE: This study establishes a role for lactate in driving nucleotide biosynthesis in DMGs. Importantly, imaging lactate production from glucose using DMI provides a readout of tumor proliferation and early response to therapy in clinically relevant DMG models. Our studies lay the foundation for precision metabolic imaging of DMG patients.
    DOI:  https://doi.org/10.1101/2025.01.02.631150
  6. STAR Protoc. 2025 Jan 10. pii: S2666-1667(24)00683-X. [Epub ahead of print]6(1): 103518
    Live-cell metabolic analyzer protocol for measuring glucose and lactate metabolic changes in human cells.
    Kenji Miki, Mikako Yagi, Ko Igami, Hiroki Kittaka, Akito Tani, Natsuki Horiuchi, Satoshi Fukumoto, Koji Yoshimoto, Takeshi Uchiumi.
      Understanding metabolic conditions related to glycolysis dependence is crucial for developing new treatments in cancer and regenerative medicine. This protocol details a method for using the live-cell metabolic analyzer (LiCellMo) to measure continuous changes in glucose consumption and lactate production in cultured human cells. LiCellMo provides real-time data on consecutive metabolic changes, improving measurements of these processes in various contexts, including in cancer and regenerative treatments.
    Keywords:  cell biology; cell culture; metabolism
    DOI:  https://doi.org/10.1016/j.xpro.2024.103518
  7. bioRxiv. 2024 Dec 12. pii: 2024.12.10.627730. [Epub ahead of print]
    Spatially resolved rewiring of mitochondria-lipid droplet interactions in hepatic lipid homeostasis.
    Sun Woo Sophie Kang, Lauryn A Brown, Colin B Miller, Katherine M Barrows, Jihye L Golino, Constance M Cultraro, Daniel Feliciano, Mercedes B Cornelius-Muwanuzi, Andy D Tran, Michael Kruhlak, Alexei Lobanov, Maggie Cam, Natalie Porat-Shliom.
      Hepatic lipid accumulation, or Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), is a significant risk factor for liver cancer. Despite the rising incidence of MASLD, the underlying mechanisms of steatosis and lipotoxicity remain poorly understood. Interestingly, lipid accumulation also occurs during fasting, driven by the mobilization of adipose tissue-derived fatty acids into the liver. However, how hepatocytes adapt to increased lipid flux during nutrient deprivation and what occurs differently in MASLD is not known. To investigate the differences in lipid handling in response to nutrient deficiency and excess, we developed a novel single-cell tissue imaging (scPhenomics) technique coupled with spatial proteomics. Our investigation revealed extensive remodeling of lipid droplet (LD) and mitochondrial topology in response to dietary conditions. Notably, fasted mice exhibited extensive mitochondria-LD interactions, which were rarely observed in Western Diet (WD)-fed mice. Spatial proteomics showed an increase in PLIN5 expression, a known mediator of LD-mitochondria interaction, in response to fasting. To examine the functional role of mitochondria-LD interaction on lipid handling, we overexpressed PLIN5 variants. We found that the phosphorylation state of PLIN5 impacts its capacity to form mitochondria-LD contact sites. PLIN5 S155A promoted extensive organelle interactions, triglyceride (TG) synthesis, and LD expansion in mice fed a control diet. Conversely, PLIN5 S155E expressing cells had fewer LDs and contact sites and contained less TG. Wild-type (WT) PLIN5 overexpression in WD-fed mice reduced steatosis and improved redox state despite continued WD consumption. These findings highlight the importance of organelle interactions in lipid metabolism, revealing a critical mechanism by which hepatocytes maintain homeostasis during metabolic stress. Our study underscores the potential utility of targeting mitochondria-LD interactions for therapeutic intervention.
    DOI:  https://doi.org/10.1101/2024.12.10.627730
  8. Sci Rep. 2025 Jan 11. 15(1): 1691
    Integrated RNA sequencing analysis and machine learning identifies a metabolism-related prognostic signature in clear cell renal cell carcinoma.
    Yunxun Liu, Zhiwei Yan, Cheng Liu, Rui Yang, Qingyuan Zheng, Jun Jian, Minghui Wang, Lei Wang, Xiaodong Weng, Zhiyuan Chen, Xiuheng Liu.
      The connection between metabolic reprogramming and tumor progression has been demonstrated in an increasing number of researches. However, further research is required to identify how metabolic reprogramming affects interpatient heterogeneity and prognosis in clear cell renal cell carcinoma (ccRCC). In this work, single-cell RNA sequencing (scRNA-seq) based deconvolution was utilized to create a malignant cell hierarchy with metabolic differences and to investigate the relationship between metabolic biomarkers and prognosis. Simultaneously, we created a machine learning-based approach for creating metabolism-related prognostic signature (MRPS). Gamma-glutamyltransferase 6 (GGT6) was further explored for deep biological insights through in vitro experiments. Compared to 51 published signatures and conventional clinical features, MRPS showed substantially higher accuracy. Meanwhile, high MRPS-risk samples demonstrated an immunosuppressive phenotype with more infiltrations of regulatory T cell (Treg) and tumour-associated macrophage (TAM). Following the administration of immune checkpoint inhibitors (ICIs), MRPS showed consistent and strong performance and was an independent risk factor for overall survival. GGT6, an essential metabolic indicator and component of MRPS, has been proven to support proliferation and invasion in ccRCC. MRPS has the potential to be a highly effective tool in improving the clinical results of patients with ccRCC.
    Keywords:  Cell metabolic reprogramming; Clear cell renal cell carcinoma; Machine learning; Prognosis; Single-cell RNA sequencing
    DOI:  https://doi.org/10.1038/s41598-025-85618-7
  9. Cell Rep. 2025 Jan 11. pii: S2211-1247(24)01550-X. [Epub ahead of print]44(1): 115199
    IL-7 promotes integrated glucose and amino acid sensing during homeostatic CD4+ T cell proliferation.
    Seema Bachoo, Nancy Gudgeon, Rebecca Mann, Victoria Stavrou, Emma L Bishop, Audrey Kelly, Alejandro Huerta Uribe, Jordan Loeliger, Corina Frick, Oliver D K Maddocks, Paul Lavender, Christoph Hess, Sarah Dimeloe.
      Interleukin (IL)-7 promotes T cell expansion during lymphopenia. We studied the metabolic basis in CD4+ T cells, observing increased glucose usage for nucleotide synthesis and oxidation in the tricarboxylic acid (TCA) cycle. Unlike other TCA metabolites, glucose-derived citrate does not accumulate upon IL-7 exposure, indicating diversion into other processes. In agreement, IL-7 promotes glucose-dependent histone acetylation and chromatin accessibility, notable at the loci of the amino acid-sensing Ragulator complex. Consistently, the expression of its subunit late endosomal/lysosomal adaptor, MAPK and mTOR activator 5 (LAMTOR5) is promoted by IL-7 in a glucose-dependent manner, and glucose availability determines amino acid-dependent mechanistic target of rapamycin (mTOR) activation, confirming integrated nutrient sensing. LAMTOR5 deletion impairs IL-7-mediated T cell expansion, establishing that glycolysis in the absence of Ragulator activation is insufficient to support this. Clinically, CD4+ T cells from stem cell transplant recipients demonstrate coordinated upregulation of glycolytic and TCA cycle enzymes, amino acid-sensing machinery, and mTOR targets, highlighting the potential to therapeutically target this pathway to fine-tune lymphopenia-induced T cell proliferation.
    Keywords:  IL-7; Immunology; Metabolism; T cell; T lymphocyte; mTOR; metabolism; nutrient sensing; proliferation
    DOI:  https://doi.org/10.1016/j.celrep.2024.115199
  10. Nat Metab. 2025 Jan 15.
    Autophagy regulator ATG5 preserves cerebellar function by safeguarding its glycolytic activity.
    Janine Tutas, Marianna Tolve, Ebru Özer-Yildiz, Lotte Ickert, Ines Klein, Quinn Silverman, Filip Liebsch, Frederik Dethloff, Patrick Giavalisco, Heike Endepols, Theodoros Georgomanolis, Bernd Neumaier, Alexander Drzezga, Guenter Schwarz, Bernard Thorens, Graziana Gatto, Christian Frezza, Natalia L Kononenko.
      Dysfunctions in autophagy, a cellular mechanism for breaking down components within lysosomes, often lead to neurodegeneration. The specific mechanisms underlying neuronal vulnerability due to autophagy dysfunction remain elusive. Here we show that autophagy contributes to cerebellar Purkinje cell (PC) survival by safeguarding their glycolytic activity. Outside the conventional housekeeping role, autophagy is also involved in the ATG5-mediated regulation of glucose transporter 2 (GLUT2) levels during cerebellar maturation. Autophagy-deficient PCs exhibit GLUT2 accumulation on the plasma membrane, along with increased glucose uptake and alterations in glycolysis. We identify lysophosphatidic acid and serine as glycolytic intermediates that trigger PC death and demonstrate that the deletion of GLUT2 in ATG5-deficient mice mitigates PC neurodegeneration and rescues their ataxic gait. Taken together, this work reveals a mechanism for regulating GLUT2 levels in neurons and provides insights into the neuroprotective role of autophagy by controlling glucose homeostasis in the brain.
    DOI:  https://doi.org/10.1038/s42255-024-01196-4
  11. Cancer Res. 2025 Jan 13.
    MTHFD2 Enhances cMYC O-GlcNAcylation to Promote Sunitinib Resistance in Renal Cell Carcinoma.
    Jinwen Liu, Gaowei Huang, Hao Lin, Rui Yang, Wenhao Zhan, Cheng Luo, Yukun Wu, Lingwu Chen, Xiaopeng Mao, Junxing Chen, Bin Huang.
      Sunitinib is a first-line targeted therapy for patients with renal cell carcinoma (RCC), but resistance represents a significant obstacle to the treatment of advanced and metastatic RCC. Metabolic reprogramming is a characteristic of RCC, and changes in metabolic processes might contribute to resistance to sunitinib. Here, we identified MTHFD2, a mitochondrial enzyme involved in one-carbon metabolism, as a critical mediator of sunitinib resistance in RCC. MTHFD2 was elevated in sunitinib resistant RCC cells, and loss of MTHDF2 conferred sensitivity to sunitinib. In patients, MTHFD2 was highly expressed in RCC and was associated with poor outcomes. Mechanistically, MTHFD2 stimulated UDP-GlcNAc biosynthesis and promoted cMYC O-GlcNAcylation by driving the folate cycle. O-GlcNAcylation enhanced cMYC stability and promoted MTHFD2 and CCND1 transcription. Targeting MTHFD2 or cyclin D1 sensitized tumor cells to sunitinib in vitro and in vivo. Consistently, development of a peptide drug capable of efficiently degrading MTHFD2 enabled reversal of sunitinib resistance in RCC. These findings identify a noncanonical metabolic function of MTHFD2 in cell signaling and response to therapy and reveal the interplay between one-carbon metabolism and sunitinib resistance in RCC. Targeting MTHFD2 could be an effective approach to overcome sunitinib resistance.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-24-0050
  12. Cell Rep. 2025 Jan 13. pii: S2211-1247(24)01530-4. [Epub ahead of print]44(1): 115179
    mTORC1 regulates the pyrimidine salvage pathway by controlling UCK2 turnover via the CTLH-WDR26 E3 ligase.
    Brittany Q Pham, Sang Ah Yi, Alban Ordureau, Heeseon An.
      One critical aspect of cell proliferation is increased nucleotide synthesis, including pyrimidines. Pyrimidines are synthesized through de novo and salvage pathways. Prior studies established that the mammalian target of rapamycin complex 1 (mTORC1) promotes pyrimidine synthesis by activating the de novo pathway for cell proliferation. However, the involvement of mTORC1 in regulating the salvage pathway remains unclear. Here, we report that mTORC1 controls the half-life of uridine cytidine kinase 2 (UCK2), the rate-limiting enzyme in the salvage pathway. Specifically, UCK2 is degraded via the CTLH-WDR26 E3 complex during mTORC1 inhibition, which is prevented when mTORC1 is active. We also find that UCK1, an isoform of UCK2, affects the turnover of UCK2 by influencing its cellular localization. Importantly, altered UCK2 levels through the mTORC1-CTLH E3 pathway affect pyrimidine salvage and the efficacy of pyrimidine analog prodrugs. Therefore, mTORC1-CTLH E3-mediated degradation of UCK2 adds another layer of complexity to mTORC1's role in regulating pyrimidine metabolism.
    Keywords:  CP: Metabolism; CP: Molecular biology; CTLH; UCK2; WDR26; YPEL5; degradomics; mTOR; mTORC1; pyrimidine; pyrimidine salvage; ubiquitin
    DOI:  https://doi.org/10.1016/j.celrep.2024.115179
  13. Methods Mol Biol. 2025 ;2891 1-14
    Metabolic Profiling: A Perspective on the Current Status, Challenges, and Future Directions.
    Helen G Gika, Georgios Theodoridis, Ian D Wilson.
      Metabolic profiling continues to develop, and research is now conducted on this topic globally in hundreds of laboratories, from small groups up to national centers and core facilities. Here we briefly provide a perspective on the current status and challenges facing metabolic phenotyping (metabonomics/metabolomics) and consider future directions for this important area of biomarker and systems biology research.
    Keywords:  Biomarker discovery; Metabolic markers; Metabolic phenotyping; Metabolic profiling; Metabolomics; Metabonomics
    DOI:  https://doi.org/10.1007/978-1-0716-4334-1_1
  14. Int J Mol Sci. 2025 Jan 06. pii: 427. [Epub ahead of print]26(1):
    Glutaminase-2 Expression Induces Metabolic Changes and Regulates Pyruvate Dehydrogenase Activity in Glioblastoma Cells.
    Juan De Los Santos-Jiménez, José A Campos-Sandoval, Tracy Rosales, Bookyung Ko, Francisco J Alonso, Javier Márquez, Ralph J DeBerardinis, José M Matés.
      Glutaminase controls the first step in glutaminolysis, impacting bioenergetics, biosynthesis and oxidative stress. Two isoenzymes exist in humans, GLS and GLS2. GLS is considered prooncogenic and overexpressed in many tumours, while GLS2 may act as prooncogenic or as a tumour suppressor. Glioblastoma cells usually lack GLS2 while they express high GLS. We investigated how GLS2 expression modifies the metabolism of glioblastoma cells, looking for changes that may explain GLS2's potential tumour suppressive role. We developed LN-229 glioblastoma cells stably expressing GLS2 and performed isotope tracing using U-13C-glutamine and metabolomic quantification to analyze metabolic changes. Treatment with GLS inhibitor CB-839 was also included to concomitantly inhibit endogenous GLS. GLS2 overexpression resulted in extensive metabolic changes, altering the TCA cycle by upregulating part of the cycle but blocking the synthesis of the 6-carbon intermediates from acetyl-CoA. Expression of GLS2 caused downregulation of PDH activity through phosphorylation of S293 of PDHA1. GLS2 also altered nucleotide levels and induced the accumulation of methylated metabolites and S-adenosyl methionine. These changes suggest that GLS2 may be a key regulator linking glutamine and glucose metabolism, also impacting nucleotides and epigenetics. Future research should ascertain the mechanisms involved and the generalizability of these findings in cancer or physiological conditions.
    Keywords:  cancer; glioblastoma; glutaminase; glutaminase-2; glutamine; metabolomics; pyruvate dehydrogenase
    DOI:  https://doi.org/10.3390/ijms26010427
  15. J Mater Chem B. 2025 Jan 16.
    Multi-organelle imaging with dye combinations: targeting the ER, mitochondria, and plasma membrane.
    Yogesh Dubey, Sriram Kanvah.
      Multi-organelle imaging allows the visualization of multiple organelles within a single cell, allowing monitoring of the cellular processes in real-time using various fluorescent probes that target specific organelles. However, the limited availability of fluorophores and potential spectral overlap present challenges, and many optimized designs are still in nascency. In this work, we synthesized various sulfonamide-based organic fluorophores that emit in the blue, green, and red regions to target different sub-cellular organelles. By utilizing binary mixtures, we successfully demonstrated multiple imaging of the sub-cellular organelles, such as the endoplasmic reticulum, plasma membrane, and mitochondria in HeLa cells, and dual imaging of the endoplasmic reticulum and mitochondria in A549 lung carcinoma cells with the help of blue and red-emitting fluorophores without any spectral spillover. Additionally, these photostable probes allowed precise cell staining and differentiation, structural features, and live cell dynamics. This approach of utilizing fluorescent mixtures can gain traction for various cellular studies and investigations.
    DOI:  https://doi.org/10.1039/d4tb02456g
  16. Scientifica (Cairo). 2025 ;2025 5685884
    Glucosamine Inhibits the Proliferation of Hepatocellular Carcinoma Cells by Eliciting Apoptosis, Autophagy, and the Anti-Warburg Effect.
    Misako Samizu, Kaoruko Iida.
      Although glucosamine (GlcN) exhibits antitumor effects, its mechanism of action remains controversial. Additionally, its impact on hepatocellular carcinoma (HCC) is not well understood. This study aimed to investigate the antitumor effects of GlcN and its underlying mechanism in a mouse HCC cell line, Hepa1-6. GlcN treatment significantly inhibited Hepa1-6 cell proliferation. Gene expression analysis revealed that GlcN upregulated Chop and Bax while downregulating Bcl2, indicating the involvement of endoplasmic reticulum (ER) stress-induced apoptosis in the antiproliferative effects of GlcN. GlcN also increased the expression of FoxO1 and FoxO3, known tumor suppressors in various cancers. Furthermore, GlcN treatment elevated the levels of LC3II (an autophagy marker) and AMP-activated protein kinase activity, suggesting intracellular energy shortage. Indeed, GlcN treatment significantly suppressed glycolytic flux, lactate, and ATP production. Supplementing GlcN treatment with a high glucose concentration (20 mM) significantly attenuated its effect. We postulate that GlcN inhibits Hepa1-6 cell growth by inducing ER stress-induced apoptosis and autophagy and by inhibiting aerobic glycolysis (the Warburg effect), a key hallmark of cancer metabolism. Given that glucose transporter 2 (GLUT2), which is abundantly expressed in hepatocytes, has a high affinity for GlcN, these effects may result from GlcN competing with glucose for hepatocyte uptake by GLUT2. Our novel findings have potential implications for HCC treatment.
    Keywords:  aerobic glycolysis; apoptosis; autophagy; glucosamine; hepatocellular carcinoma
    DOI:  https://doi.org/10.1155/sci5/5685884
  17. Acta Physiol (Oxf). 2025 Feb;241(2): e14261
    Ultrafast multicellular calcium imaging of calcium spikes in mouse beta cells in tissue slices.
    Jurij Dolenšek, Viljem Pohorec, Maša Skelin Klemen, Marko Gosak, Andraž Stožer.
       BACKGROUND: The crucial steps in beta cell stimulus-secretion coupling upon stimulation with glucose are oscillatory changes in metabolism, membrane potential, intracellular calcium concentration, and exocytosis. The changes in membrane potential consist of bursts of spikes, with silent phases between them being dominated by membrane repolarization and absence of spikes. Assessing intra- and intercellular coupling at the multicellular level is possible with ever-increasing detail, but our current ability to simultaneously resolve spikes from many beta cells remains limited to double-impalement electrophysiological recordings.
    METHODS: Since multicellular calcium imaging of spikes would enable a better understanding of coupling between changes in membrane potential and calcium concentration in beta cell collectives, we set out to design an appropriate methodological approach.
    RESULTS: Combining the acute tissue slice method with ultrafast calcium imaging, we were able to resolve and quantify individual spikes within bursts at a temporal resolution of >150 Hz over prolonged periods, as well as describe their glucose-dependent properties. In addition, by simultaneous patch-clamp recordings we were able to show that calcium spikes closely follow membrane potential changes. Both bursts and spikes coordinate across islets in the form of intercellular waves, with bursts typically displaying global and spikes more local patterns.
    CONCLUSIONS: This method and the associated findings provide additional insight into the complex signaling within beta cell networks. Once extended to tissue from diabetic animals and human donors, this approach could help us better understand the mechanistic basis of diabetes and find new molecular targets.
    Keywords:  beta cell; calcium imaging; calcium oscillations; calcium spikes; physiology
    DOI:  https://doi.org/10.1111/apha.14261
  18. Methods Mol Biol. 2025 ;2887 263-280
    SNARE-Mediated Membrane Fusion Probed Using a Synthetic Organelle in the Living Bacterium.
    Christian Vannier, Thierry Galli.
      Studies on the mechanisms and regulation of functional assemblies of SNARE proteins mediating membrane fusion essentially make use of recombinant proteins and artificial phospholipid bilayers. We have developed an easy-to-use in vivo system reconstituting membrane fusion in living bacteria. It relies on the formation of caveolin-dependent intracytoplasmic cisternae followed by the controlled synthesis of members of the synaptic SNARE machinery. Only when a SNARE complex is formed with its intact components does the docking and subsequent fusion occur between the cisternae and the plasma membrane that is accompanied by the disappearance of the former. The phenotypic response of the bacterial cell to fusion events is a remarkable increase in cell body length due to an expansion of the plasma membrane. Therefore, such an easy-to-observe phenotype makes this system amenable to structure-function studies of SNAREs. We describe here the specific ways to produce caveolin and the SNARE proteins from compatible plasmids upon bacterial transformation and to obtain the elongated cell phenotype. We also provide protocols to carry out the preparation of cell culture samples suitable for biochemical and light microscopy analysis.
    Keywords:  Bacteriology; Bacterium; Biochemistry; Caveolin; Inducible synthesis; Light microscopy; Membrane fusion; Membrane traffic; Synaptic SNAREs; Synthetic organelle
    DOI:  https://doi.org/10.1007/978-1-0716-4314-3_19
  19. Nat Commun. 2025 Jan 11. 16(1): 596
    Engineered hypoxia-responsive albumin nanoparticles mediating mitophagy regulation for cancer therapy.
    Wenyan Wang, Shun-Yu Yao, Jingjing Luo, Chendi Ding, Qili Huang, Yao Yang, Zhaoqing Shi, Jiachan Lin, Yu-Chen Pan, Xiaowei Zeng, Dong-Sheng Guo, Hongzhong Chen.
      Hypoxic tumors present a significant challenge in cancer therapy due to their ability to adaptation in low-oxygen environments, which supports tumor survival and resistance to treatment. Enhanced mitophagy, the selective degradation of mitochondria by autophagy, is a crucial mechanism that helps sustain cellular homeostasis in hypoxic tumors. In this study, we develop an azocalix[4]arene-modified supramolecular albumin nanoparticle, that co-delivers hydroxychloroquine and a mitochondria-targeting photosensitizer, designed to induce cascaded oxidative stress by regulating mitophagy for the treatment of hypoxic tumors. These nanoparticles are hypoxia-responsive and release loaded guest molecules in hypoxic tumor cells. The released hydroxychloroquine disrupts the mitophagy process, thereby increasing oxidative stress and further weakening the tumor cells. Additionally, upon laser irradiation, the photosensitizer generates reactive oxygen species independent of oxygen, inducing mitochondria damage and mitophagy activation. The dual action of simultaneous spatiotemporal mitophagy activation and mitophagy flux blockade results in enhanced autophagic and oxidative stress, ultimately driving tumor cell death. Our work highlights the effectiveness of hydroxychloroquine-mediated mitophagy blockade combined with mitochondria-targeted photosensitizer for cascade-amplified oxidative stress against hypoxic tumors.
    DOI:  https://doi.org/10.1038/s41467-025-55905-y
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