bims-celmim 2025-03-16 papers

bims-celmim

Biomed News

on Cellular and mitochondrial metabolism

Issue of 2025–03–16
23 papers selected by
Marc Segarra Mondejar

Glucose Metabolism and Tumor Microenvironment: Mechanistic Insights and Therapeutic Implications.
Succinate dehydrogenase activity supports de novo purine synthesis.
The Glutamate/GABA-Glutamine Cycle: Insights, Updates, and Advances.
Mitochondrial Dysfunction in Cardiovascular Diseases.
Exploring Metabolic Shifts in Kidney Cancer and Non-Cancer Cells Under Pro- and Anti-Apoptotic Treatments Using NMR Metabolomics.
Islet hormones at the intersection of glucose and amino acid metabolism.
Electron Microscopy to Visualize and Quantify Mitochondrial Structure and Organellar Interactions in Cultured Cells During Senescence.
Mitochondrial genetics, signalling and stress responses.
L- and D-Lactate: unveiling their hidden functions in disease and health.
MIA40 suppresses cell death induced by apoptosis-inducing factor 1.
SLC25A35 enhances fatty acid oxidation and mitochondrial biogenesis to promote the carcinogenesis and progression of hepatocellular carcinoma by upregulating PGC-1α.
Pyruvate dehydrogenase kinase 1 controls triacylglycerol hydrolysis in cardiomyocytes.
β-Hydroxybutyrate enhances brain metabolism in normoglycemia and hyperglycemia, providing cerebroprotection in a mouse stroke model.
Mitochondria are positioned at dendritic branch induction sites, a process requiring rhotekin2 and syndapin I.
Glucose-dependent metabolism of hippocampal primary neurons in response to chemically induced long-term potentiation.
Unraveling the mystery of citrate transporters in Alzheimer's disease: An updated review.
SLC5A3 depletion promotes apoptosis by inducing mitochondrial dysfunction and mitophagy in gemcitabine-resistant pancreatic cancer cells.
Dynamic investigation of hypoxia-induced L-lactylation.
Sphingolipid metabolism drives mitochondria remodeling during aging and oxidative stress.
CYP51A1 drives resistance to pH-dependent cell death in pancreatic cancer.
Targeting metabolic reprogramming in glioblastoma as a new strategy to overcome therapy resistance.
Time Series Imaging the Mitochondrial Microenvironment and Its Interactions with Lysosomes during Ferroptosis.
Measurement of Mitochondrial Membrane Potential In Vivo using a Genetically Encoded Voltage Indicator.

Int J Mol Sci. 2025 Feb 22. pii: 1879. [Epub ahead of print]26(5):

Glucose Metabolism and Tumor Microenvironment: Mechanistic Insights and Therapeutic Implications.

Wiktoria Andryszkiewicz, Julia Gąsiorowska, Maja Kübler, Karolina Kublińska, Agata Pałkiewicz, Adam Wiatkowski, Urszula Szwedowicz, Anna Choromańska.

  Metabolic reprogramming in cancer cells involves changes in glucose metabolism, glutamine utilization, and lipid production, as well as promoting increased cell proliferation, survival, and immune resistance by altering the tumor microenvironment. Our study analyzes metabolic reprogramming in neoplastically transformed cells, focusing on changes in glucose metabolism, glutaminolysis, and lipid synthesis. Moreover, we discuss the therapeutic potential of targeting cancer metabolism, focusing on key enzymes involved in glycolysis, the pentose phosphate pathway, and amino acid metabolism, including lactate dehydrogenase A, hexokinase, phosphofructokinase and others. The review also highlights challenges such as metabolic heterogeneity, adaptability, and the need for personalized therapies to overcome resistance and minimize adverse effects in cancer treatment. This review underscores the significance of comprehending metabolic reprogramming in cancer cells to engineer targeted therapies, personalize treatment methodologies, and surmount challenges, including metabolic plasticity and therapeutic resistance.

Keywords:  cancer stem cells; glycolysis; hexokinase; lactate dehydrogenase A; phosphofructokinase; pyruvate kinase; the Warburg effect; tumor microenvironment; tumor-associated macrophages

DOI:  https://doi.org/10.3390/ijms26051879
bioRxiv. 2025 Mar 01. pii: 2025.02.26.640389. [Epub ahead of print]

Succinate dehydrogenase activity supports de novo purine synthesis.

Mushtaq A Nengroo, Austin T Klein, Heather S Carr, Olivia Vidal-Cruchez, Umakant Sahu, Daniel J McGrail, Nidhi Sahni, Peng Gao, John M Asara, Hardik Shah, Marc L Mendillo, Issam Ben-Sahra.

The de novo purine synthesis pathway is fundamental for nucleic acid production and cellular energetics, yet the role of mitochondrial metabolism in modulating this process remains underexplored. In many cancers, metabolic reprogramming supports rapid proliferation and survival, but the specific contributions of the tricarboxylic acid (TCA) cycle enzymes to nucleotide biosynthesis are not fully understood. Here, we demonstrate that the TCA cycle enzyme succinate dehydrogenase (SDH) is essential for maintaining optimal de novo purine synthesis in normal and cancer cells. Genetic or pharmacological inhibition of SDH markedly attenuates purine synthesis, leading to a significant reduction in cell proliferation. Mechanistically, SDH inhibition causes an accumulation of succinate, which directly impairs the purine biosynthetic pathway. In response, cancer cells compensate by upregulating the purine salvage pathway, a metabolic adaptation that represents a potential therapeutic vulnerability. Notably, co-inhibition of SDH and the purine salvage pathway induces pronounced antiproliferative and antitumoral effects in preclinical models. These findings not only reveal a signaling role for mitochondrial succinate in regulating nucleotide metabolism but also provide a promising therapeutic strategy for targeting metabolic dependencies in cancer.

DOI: https://doi.org/10.1101/2025.02.26.640389
J Neurochem. 2025 Mar;169(3): e70029

The Glutamate/GABA-Glutamine Cycle: Insights, Updates, and Advances.

Jens V Andersen.

  Synaptic homeostasis of the principal neurotransmitters glutamate and GABA is tightly regulated by an intricate metabolic coupling between neurons and astrocytes known as the glutamate/GABA-glutamine cycle. In this cycle, astrocytes take up glutamate and GABA from the synapse and convert these neurotransmitters into glutamine. Astrocytic glutamine is subsequently transferred to neurons, serving as the principal precursor for neuronal glutamate and GABA synthesis. The glutamate/GABA-glutamine cycle integrates multiple cellular processes, including neurotransmitter release, uptake, synthesis, and metabolism. All of these processes are deeply interdependent and closely coupled to cellular energy metabolism. Astrocytes display highly active mitochondrial oxidative metabolism and several unique metabolic features, including glycogen storage and pyruvate carboxylation, which are essential to sustain continuous glutamine release. However, new roles of oligodendrocytes and microglia in neurotransmitter recycling are emerging. Malfunction of the glutamate/GABA-glutamine cycle can lead to severe synaptic disruptions and may be implicated in several brain diseases. Here, I review central aspects and recent advances of the glutamate/GABA-glutamine cycle to highlight how the cycle is functionally connected to critical brain functions and metabolism. First, an overview of glutamate, GABA, and glutamine transport is provided in relation to neurotransmitter recycling. Then, central metabolic aspects of the glutamate/GABA-glutamine cycle are reviewed, with a special emphasis on the critical metabolic roles of glial cells. Finally, I discuss how aberrant neurotransmitter recycling is linked to neurodegeneration and disease, focusing on astrocyte metabolic dysfunction and brain lipid homeostasis as emerging pathological mechanisms. Instead of viewing the glutamate/GABA-glutamine cycle as individual biochemical processes, a more holistic and integrative approach is needed to advance our understanding of how neurotransmitter recycling modulates brain function in both health and disease.

Keywords:  Alzheimer's disease; astrocytes; lipid metabolism; mitochondrial function; neurodegeneration; neurotransmitter recycling

DOI:  https://doi.org/10.1111/jnc.70029
Int J Mol Sci. 2025 Feb 23. pii: 1917. [Epub ahead of print]26(5):

Mitochondrial Dysfunction in Cardiovascular Diseases.

Han-Mo Yang.

  Mitochondrial dysfunction is increasingly recognized as a central contributor to the pathogenesis of cardiovascular diseases (CVDs), including heart failure, ischemic heart disease, hypertension, and cardiomyopathy. Mitochondria, known as the powerhouses of the cell, play a vital role in maintaining cardiac energy homeostasis, regulating reactive oxygen species (ROS) production and controlling cell death pathways. Dysregulated mitochondrial function results in impaired adenosine triphosphate (ATP) production, excessive ROS generation, and activation of apoptotic and necrotic pathways, collectively driving the progression of CVDs. This review provides a detailed examination of the molecular mechanisms underlying mitochondrial dysfunction in CVDs, including mutations in mitochondrial DNA (mtDNA), defects in oxidative phosphorylation (OXPHOS), and alterations in mitochondrial dynamics (fusion, fission, and mitophagy). Additionally, the role of mitochondrial dysfunction in specific cardiovascular conditions is explored, highlighting its impact on endothelial dysfunction, myocardial remodeling, and arrhythmias. Emerging therapeutic strategies targeting mitochondrial dysfunction, such as mitochondrial antioxidants, metabolic modulators, and gene therapy, are also discussed. By synthesizing recent advances in mitochondrial biology and cardiovascular research, this review aims to enhance understanding of the role of mitochondria in CVDs and identify potential therapeutic targets to improve cardiovascular outcomes.

Keywords:  cardiovascular disease; mitochondrial dynamics; mitochondrial dysfunction; oxidative stress

DOI:  https://doi.org/10.3390/ijms26051917
Cells. 2025 Mar 02. pii: 367. [Epub ahead of print]14(5):

Exploring Metabolic Shifts in Kidney Cancer and Non-Cancer Cells Under Pro- and Anti-Apoptotic Treatments Using NMR Metabolomics.

Lucia Trisolini, Biagia Musio, Beatriz Teixeira, Maria Noemi Sgobba, Anna Lucia Francavilla, Mariateresa Volpicella, Lorenzo Guerra, Anna De Grassi, Vito Gallo, Iola F Duarte, Ciro Leonardo Pierri.

  This study investigates the metabolic responses of cancerous (RCC) and non-cancerous (HK2) kidney cells to treatment with Staurosporine (STAU), which has a pro-apoptotic effect, and Bongkrekic acid (BKA), which has an anti-apoptotic effect, individually and in combination, using 1H NMR metabolomics to identify metabolite markers linked to mitochondrial apoptotic pathways. BKA had minimal metabolic effects in RCC cells, suggesting its role in preserving mitochondrial function without significantly altering metabolic pathways. In contrast, STAU induced substantial metabolic reprogramming in RCC cells, disrupting energy production, redox balance, and biosynthesis, thereby triggering apoptotic pathways. The combined treatment of BKA and STAU primarily mirrored the effects of STAU alone, with BKA showing little capacity to counteract the pro-apoptotic effects. In non-cancerous HK2 cells, the metabolic alterations were far less pronounced, highlighting key differences in the metabolic responses of cancerous and non-cancerous cells. RCC cells displayed greater metabolic flexibility, while HK2 cells maintained a more regulated metabolic state. These findings emphasize the potential for targeting cancer-specific metabolic vulnerabilities while sparing non-cancerous cells, underscoring the value of metabolomics in understanding apoptotic and anti-apoptotic mechanisms. Future studies should validate these results in vivo and explore their potential for personalized treatment strategies.

Keywords:  Bongkrekic acid; NMR metabolomics; Staurosporine; apoptosis; kidney cell lines; mitochondria

DOI:  https://doi.org/10.3390/cells14050367
Nat Rev Endocrinol. 2025 Mar 07.

Islet hormones at the intersection of glucose and amino acid metabolism.

Phillip J White, Nicolai J Wewer Albrechtsen, Jonathan E Campbell.

The pancreatic islets of Langerhans are central to fine-tuning metabolism to ensure metabolic homeostasis during the transition between fasting and feeding. Insulin and glucagon, the principal hormones generated and secreted by islets, exert powerful control in various metabolic tissues to drive nutrient uptake, storage and metabolism. Their canonical actions on glycaemia have positioned these hormones in opposition, however, their metabolic actions extend beyond controlling blood levels of glucose. Indeed, these islet hormones are just as influential in regulating lipid and amino acid metabolism and it is becoming clear that many of these actions involve an interplay between insulin and glucagon, which is contrary to the dogmatic view that these hormones are antagonistic in nature. Finally, we postulate that examining the effects of islet hormones on the metabolism of individual metabolites is overly simplistic. Here, we discuss the actions of each islet hormone alone and in combination with the others in regulating glucose and amino acid metabolism and explore how these signalling networks are closely linked and strongly influence one another.

DOI: https://doi.org/10.1038/s41574-025-01100-4
Methods Mol Biol. 2025 ;2906 229-242

Electron Microscopy to Visualize and Quantify Mitochondrial Structure and Organellar Interactions in Cultured Cells During Senescence.

Christina Glytsou.

  Mitochondria are multifunctional organelles that play a crucial role in numerous cellular processes, including oncogene-induced senescence. Recent studies have demonstrated that mitochondria undergo notable morphological and functional changes during senescence, with mitochondria dysregulation being a critical factor contributing to the induction of this state. To elucidate the intricate and dynamic structure of these organelles, high-resolution visualization techniques are imperative. Electron microscopy offers nanometer-scale resolution images, enabling the comprehensive study of organelles' architecture. This chapter provides a detailed guide for preparing fixed samples from cultured cells for electron microscopy imaging. It also describes various quantification methods to accurately assess organellar parameters, including morphometric measurements of mitochondrial shape, cristae structure, and mitochondria-endoplasmic reticulum contact sites. These analyses yield valuable insights into the status of subcellular organelles, advancing our understanding of their involvement in cellular senescence and disease.

Keywords:  EM sample preparation; Electron microscopy; MERCs; Mitochondria visualization; Mitochondrial structure

DOI:  https://doi.org/10.1007/978-1-0716-4426-3_13
Nat Cell Biol. 2025 Mar;27(3): 393-407

Mitochondrial genetics, signalling and stress responses.

Yasmine J Liu, Jonathan Sulc, Johan Auwerx.

Mitochondria are multifaceted organelles with crucial roles in energy generation, cellular signalling and a range of synthesis pathways. The study of mitochondrial biology is complicated by its own small genome, which is matrilineally inherited and not subject to recombination, and present in multiple, possibly different, copies. Recent methodological developments have enabled the analysis of mitochondrial DNA (mtDNA) in large-scale cohorts and highlight the far-reaching impact of mitochondrial genetic variation. Genome-editing techniques have been adapted to target mtDNA, further propelling the functional analysis of mitochondrial genes. Mitochondria are finely tuned signalling hubs, a concept that has been expanded by advances in methodologies for studying the function of mitochondrial proteins and protein complexes. Mitochondrial respiratory complexes are of dual genetic origin, requiring close coordination between mitochondrial and nuclear gene-expression systems (transcription and translation) for proper assembly and function, and recent findings highlight the importance of the mitochondria in this bidirectional signalling.

DOI: https://doi.org/10.1038/s41556-025-01625-w
Cell Commun Signal. 2025 Mar 12. 23(1): 134

L- and D-Lactate: unveiling their hidden functions in disease and health.

Jianting Li, Peng Ma, Zhizhen Liu, Jun Xie.

  Lactate, once considered a mere byproduct of anaerobic metabolism, is now recognized as a critical signaling molecule with diverse roles in physiology and pathology. There are two stereoisomers of lactate: L- and D-lactate. Recent studies have shown that disruptions in these two lactate stereoisomers have distinct effects on health and disease. L-lactate is central to glycolysis and energy transfer through the Cori cycle but also acts as the dominant lactylation isomer induced by glycolysis, influencing metabolism and cell survival. Although less studied, D-lactate is linked to metabolic disorders and plays a role in mitochondrial dysfunction and oxidative stress. This review focuses on both L- and D-lactate and examines their biosynthesis, transport, and expanding roles in physiological and pathological processes, particularly their functions in cancer, immune regulation, inflammation, neurodegeneration and other diseases. Finally, we assess the therapeutic prospects of targeting lactate metabolism, highlighting emerging strategies for intervention in clinical settings. Our review synthesizes the current understanding of L- and D-lactate, offering insights into their potential as targets for therapeutic innovation.

Keywords:  D-lactate; Epigenetic; L-lactate; Lactylation; Metabolism

DOI:  https://doi.org/10.1186/s12964-025-02132-z
EMBO Rep. 2025 Mar 07.

MIA40 suppresses cell death induced by apoptosis-inducing factor 1.

Ben Hur Marins Mussulini, Klaudia K Maruszczak, Piotr Draczkowski, Mayra A Borrero-Landazabal, Selvaraj Ayyamperumal, Artur Wnorowski, Michal Wasilewski, Agnieszka Chacinska.

  Mitochondria harbor respiratory complexes that perform oxidative phosphorylation. Complex I is the first enzyme of the respiratory chain that oxidizes NADH. A dysfunction in complex I can result in higher cellular levels of NADH, which in turn strengthens the interaction between apoptosis-inducing factor 1 (AIFM1) and Mitochondrial intermembrane space import and assembly protein 40 (MIA40) in the mitochondrial intermembrane space. We investigated whether MIA40 modulates the activity of AIFM1 upon increased NADH/NAD+ balance. We found that in model cells characterized by an increase in NADH the AIFM1-MIA40 interaction is strengthened and these cells demonstrate resistance to AIFM1-induced cell death. Either silencing of MIA40, rescue of complex I, or depletion of NADH through the expression of yeast NADH-ubiquinone oxidoreductase-2 sensitized NDUFA13-KO cells to AIFM1-induced cell death. These findings indicate that the complex of MIA40 and AIFM1 suppresses AIFM1-induced cell death in a NADH-dependent manner. This study identifies an effector complex involved in regulating the programmed cell death that accommodates the metabolic changes in the cell and provides a molecular explanation for AIFM1-mediated chemoresistance of cancer cells.

Keywords:  Cancer; Metabolism; Mitochondria; Programmed Cell Death; Protein Import

DOI:  https://doi.org/10.1038/s44319-025-00406-8
Cell Commun Signal. 2025 Mar 10. 23(1): 130

SLC25A35 enhances fatty acid oxidation and mitochondrial biogenesis to promote the carcinogenesis and progression of hepatocellular carcinoma by upregulating PGC-1α.

Heng-Chao Yu, Lu Bai, Liang Jin, Yu-Jia Zhang, Zi-Han Xi, De-Sheng Wang.

  Mitochondria dysfunction has been closely linked to a wide spectrum of human cancers, whereas the molecular basis has yet to be fully understood. SLC25A35 belongs to the SLC25 family of mitochondrial carrier proteins. However, the role of SLC25A35 in mitochondrial metabolism reprogramming, development and progression in human cancers remains unclear. Here, we found that SLC25A35 markedly reprogramed mitochondrial metabolism, characterized by increased oxygen consumption rate and ATP production and decreased ROS level, via enhancing fatty acid oxidation (FAO). Meanwhile, SLC25A35 also enhanced mitochondrial biogenesis characterized by increased mitochondrial mass and DNA content. Mechanistic studies revealed that SLC25A35 facilitated FAO and mitochondrial biogenesis through upregulating peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) via increasing acetyl-CoA-mediated acetylation of PGC-1α. Clinically, SLC25A35 was highly expressed in HCC and correlated with adverse patients' survival. Functionally, SLC25A35 promoted the proliferation and metastasis of HCC cells both in vitro and in vivo, as well as the carcinogenesis in a DEN-induced HCC mice model. Moreover, we found that SLC25A35 upregulation is caused, at least in part, by decreased miR-663a in HCC cells. Together, our results suggest a crucial oncogenic role of SLC25A35 in HCC by reprogramming mitochondrial metabolism and suggest SLC25A35 as a potential therapeutic target for the treatment of HCC.

Keywords:  Fatty acid oxidation; HCC; Metastasis; Mitochondrial biogenesis; Proliferation; SLC25A35

DOI:  https://doi.org/10.1186/s12964-025-02109-y
J Biol Chem. 2025 Mar 10. pii: S0021-9258(25)00247-9. [Epub ahead of print] 108398

Pyruvate dehydrogenase kinase 1 controls triacylglycerol hydrolysis in cardiomyocytes.

Michael G Atser, Chelsea D Wenyonu, Elyn M Rowe, Connie L K Leung, Haoning Howard Cen, Eric D Queathem, Leo T Liu, Renata Moravcova, Jason Rogalski, David Perrin, Peter Crawford, Leonard J Foster, Armando Alcazar, James D Johnson.

  Pyruvate dehydrogenase kinase (PDK) 1 is one of four isozymes that inhibit the oxidative decarboxylation of pyruvate to acetyl-CoA via pyruvate dehydrogenase. PDK activity is elevated in fasting or starvation conditions to conserve carbohydrate reserves. PDK has also been shown to increase mitochondrial fatty acid utilization. In cardiomyocytes, metabolic flexibility is crucial for the fulfillment of high energy requirements. The PDK1 isoform is abundant in cardiomyocytes, but its specific contribution to cardiomyocyte metabolism is unclear. Here we show that PDK1 regulates cardiomyocyte fuel preference by mediating triacylglycerol turnover in differentiated H9c2 myoblasts using lentiviral shRNA to knockdown Pdk1. Somewhat surprisingly, PDK1 loss did not affect overall PDH activity, basal glycolysis, or glucose oxidation revealed by oxygen consumption rate experiments and 13C6 glucose labelling. On the other hand, we observed decreased triacylglycerol turnover in H9c2 cells with PDK1 knockdown, which was accompanied by decreased mitochondrial fatty acid utilization following nutrient deprivation. 13C16 palmitate tracing of uniformly labelled acyl chains revealed minimal acyl chain shuffling within triacylglycerol, indicating that the triacylglycerol hydrolysis, and not re-esterification, was dysfunctional in PDK1 suppressed cells. Importantly, PDK1 loss did not significantly impact the cellular lipidome or triacylglycerol accumulation following palmitic acid treatment, suggesting that effects of PDK1 on lipid metabolism were specific to the nutrient-deprived state. We validated that PDK1 loss decreased triacylglycerol turnover in Pdk1 knockout mice. Together, these findings implicate a novel role for PDK1 in lipid metabolism in cardiomyocytes, independent of its canonical roles in glucose metabolism.

Keywords:  carbohydrate metabolism; cardiac metabolism; lipid metabolism; pyruvate dehydrogenase kinase; triacylglycerol

DOI:  https://doi.org/10.1016/j.jbc.2025.108398
bioRxiv. 2025 Feb 24. pii: 2025.02.19.639087. [Epub ahead of print]

β-Hydroxybutyrate enhances brain metabolism in normoglycemia and hyperglycemia, providing cerebroprotection in a mouse stroke model.

Deborah M Holstein, Afaf Saliba, Damian Lozano, Jiwan Kim, Kumar Sharma, James D Lechleiter.

Hyperglycemia in poorly controlled diabetes is widely recognized as detrimental to organ dysfunction. However, the acute effects of hyperglycemia on brain metabolism and function are not fully understood. The potential protective benefit of ketone bodies on mitochondrial function in the brain has also not been well characterized. Here, we evaluated the acute effects of hyperglycemia and β-hydroxybutyrate (BHB) on brain metabolism by employing a novel approach leveraging adenosine triphosphate (ATP)-dependence of bioluminescence originating from luciferin-luciferase activity. Oxygen consumption rate was measured in ex vivo live brain punches to further evaluate mitochondrial function. Additionally, we investigated the functional relevance of BHB using an in vivo photothrombotic stroke model to assess its cerebroprotective effects. Our data demonstrate that brain metabolism in mice is affected by acute exposure to high glucose, at a level similar to consuming food or a beverage with high sucrose. This short-term effect of glucose exposure was reduced by co-administration with the ketone body BHB. Moreover, BHB significantly reduced infarct size in the brain stroke model, providing evidence for its functional protective role in the brain. These findings suggest that BHB may effectively mitigate the adverse effects of metabolic stress and ischemic events on brain metabolism and function.

DOI: https://doi.org/10.1101/2025.02.19.639087
Nat Commun. 2025 Mar 10. 16(1): 2353

Mitochondria are positioned at dendritic branch induction sites, a process requiring rhotekin2 and syndapin I.

Jessica Tröger, Regina Dahlhaus, Anne Bayrhammer, Dennis Koch, Michael M Kessels, Britta Qualmann.

Proper neuronal development, function and survival critically rely on mitochondrial functions. Yet, how developing neurons ensure spatiotemporal distribution of mitochondria during expansion of their dendritic arbor remained unclear. We demonstrate the existence of effective mitochondrial positioning and tethering mechanisms during dendritic arborization. We identify rhotekin2 as outer mitochondrial membrane-associated protein that tethers mitochondria to dendritic branch induction sites. Rhotekin2-deficient neurons failed to correctly position mitochondria at these sites and also lacked the reduction in mitochondrial dynamics observed at wild-type nascent dendritic branch sites. Rhotekin2 hereby serves as important anchor for the plasma membrane-binding and membrane curvature-inducing F-BAR protein syndapin I (PACSIN1). Consistently, syndapin I loss-of-function phenocopied the rhotekin2 loss-of-function phenotype in mitochondrial positioning at dendritic branch induction sites. The finding that rhotekin2 deficiency impaired dendritic branch induction and that a syndapin binding-deficient rhotekin2 mutant failed to rescue this phenotype highlighted the physiological importance of rhotekin2 functions for neuronal network formation.

DOI: https://doi.org/10.1038/s41467-025-57399-0
bioRxiv. 2025 Feb 25. pii: 2025.02.24.639988. [Epub ahead of print]

Glucose-dependent metabolism of hippocampal primary neurons in response to chemically induced long-term potentiation.

Natalia Pudelko-Malik, Dominika Drulis-Fajdasz, Mateusz Fydryszewski, Shawn Burgess, Piotr Mlynarz, Dariusz Rakus, Stanislaw Deja.

Glucose is a predominant fuel for the brain supporting its high energy demand associated with neuronal signaling and synaptic activity. Long-term potentiation (LTP) is required for learning and memory formation by generating long lasting increase in synaptic strength and signal transmission between two neurons. While the electrophysiological bases of LTP are well established, much less is known about the metabolic demands of neurons involved in LTP. Common protocols used to examine synaptic activity rely on high glucose concentrations which are far from physiological glucose levels found in the brain. Here we used primary hippocampal neurons cultured under physiological (2.5 mM) and high (25 mM) glucose to investigate the metabolic effects of chemically induced LTP. Physiological glucose was associated with neuronal survival while high glucose promoted "PAS granule" accumulation. Changes in glucose altered extracellular lactate and pyruvate concentrations and affected key intracellular metabolic intermediates and neurotransmitter levels in neuronal cells without depleting the TCA cycle. LTP induction was comparable, but mitochondrial and neurotransmitter response to LTP was differentially affected physiological and high glucose conditions. Glycogen phosphorylase inhibition had minimal effects in physiological glucose but impaired synaptic responses and altered metabolite dynamics in high glucose. Our findings demonstrate that neuronal mitochondrial metabolism is closely linked to synaptic plasticity and highlight the importance of studying neurophysiological activity physiologically relevant glucose conditions.

DOI: https://doi.org/10.1101/2025.02.24.639988
Ageing Res Rev. 2025 Mar 10. pii: S1568-1637(25)00072-8. [Epub ahead of print] 102726

Unraveling the mystery of citrate transporters in Alzheimer's disease: An updated review.

Anirban Goutam Mukherjee, Shatakshi Mishra, Abilash Valsala Gopalakrishnan, Sandra Kannampuzha, Reshma Murali, Uddesh Ramesh Wanjari, B Stany, Balachandar Vellingiri, Harishkumar Madhyastha, Kanagavel Deepankumar, Murali Vijayan.

  A key molecule in cellular metabolism, citrate is essential for lipid biosynthesis, energy production, and epigenetic control. The etiology of Alzheimer's disease (AD), a progressive neurodegenerative illness marked by memory loss and cognitive decline, may be linked to dysregulated citrate transport, according to recent research. Citrate transporters, which help citrate flow both inside and outside of cells, are becoming more and more recognized as possible participants in the molecular processes underlying AD. Citrate synthase (CS), a key enzyme in the tricarboxylic acid (TCA) cycle, supports mitochondrial function and neurotransmitter synthesis, particularly acetylcholine (ACh), essential for cognition. Changes in CS activity affect citrate availability, influencing energy metabolism and neurotransmitter production. Choline, a precursor for ACh, is crucial for neuronal function. Lipid metabolism, oxidative stress reactions, and mitochondrial function can all be affected by aberrant citrate transport, and these changes are linked to dementia. Furthermore, the two main pathogenic characteristics of AD, tau hyperphosphorylation and amyloid-beta (Aβ) aggregation, may be impacted by disturbances in citrate homeostasis. The goal of this review is to clarify the complex function of citrate transporters in AD and provide insight into how they contribute to the development and course of the illness. We aim to provide an in-depth idea of which particular transporters are dysregulated in AD and clarify the functional implications of these dysregulated transporters in brain cells. To reduce neurodegenerative processes and restore metabolic equilibrium, we have also discussed the therapeutic potential of regulating citrate transport. Gaining insight into the relationship between citrate transporters and the pathogenesis of AD may help identify new indicators for early detection and creative targets for treatment. This study offers hope for more potent ways to fight this debilitating illness and is a crucial step in understanding the metabolic foundations of AD.

Keywords:  Alzheimer’s disease; acetylcholine; aging; citrate synthase; citrate transporter; therapeutic target

DOI:  https://doi.org/10.1016/j.arr.2025.102726
Cell Death Dis. 2025 Mar 07. 16(1): 161

SLC5A3 depletion promotes apoptosis by inducing mitochondrial dysfunction and mitophagy in gemcitabine-resistant pancreatic cancer cells.

Minsoo Kim, Woosol Chris Hong, Hyeon Woong Kang, Ju Hyun Kim, Dongyong Lee, Jae-Ho Cheong, Hye-Sol Jung, Wooil Kwon, Jin-Young Jang, Hyo Jung Kim, Joon Seong Park.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with poor prognosis, largely due to the rapid development of chemoresistance in patients. Mitochondrial dynamics play a crucial role in cancer cell survival. Currently, the specific mechanisms underlying gemcitabine resistance in PDAC remain unknown. In this study, we identified the sodium/myo-inositol co-transporter solute carrier family 5 member 3 (SLC5A3) as a key modulator promoting chemoresistance in PDAC. SLC5A3 levels were significantly upregulated in gemcitabine-resistant PDAC cells, enhancing their cell survival by stabilizing the mitochondrial functions and inhibiting apoptosis. Mitochondrial analysis showed that SLC5A3 inhibition disrupted the mitochondrial dynamics, leading to increased reactive oxygen species production, mitochondrial fission, and impaired oxidative phosphorylation. Moreover, SLC5A3 inhibition activated the PTEN-induced kinase 1/Parkin-mediated mitophagy pathway, resulting in the excessive removal of damaged and healthy mitochondria, thereby depleting the mitochondrial reserves and sensitizing the cells to apoptosis. In vivo studies revealed that targeting SLC5A3 enhanced the efficacy of gemcitabine and significantly reduced the tumor growth. Collectively, these results suggest SLC5A3-mediated mitochondrial regulation as a promising therapeutic strategy to overcome gemcitabine resistance in PDAC.

DOI: https://doi.org/10.1038/s41419-025-07476-5
Proc Natl Acad Sci U S A. 2025 Mar 11. 122(10): e2404899122

Dynamic investigation of hypoxia-induced L-lactylation.

Jinjun Gao, Ruilong Liu, Kevin Huang, Ziyuan Li, Xinlei Sheng, Kasturi Chakraborty, Chang Han, Di Zhang, Lev Becker, Yingming Zhao.

  The recently identified histone modification lysine lactylation can be stimulated by L-lactate and glycolysis. Although the chemical group added upon lysine lactylation was originally proposed to be the L-enantiomer of lactate (KL-la), two isomeric modifications, lysine D-lactylation (KD-la) and N-ε-(carboxyethyl) lysine (Kce), also exist in cells, with their precursors being metabolites of glycolysis. The dynamic regulation and differences among these three modifications in response to hypoxia remain poorly understood. In this study, we demonstrate that intracellular KL-la, but not KD-la or Kce, is up-regulated in response to hypoxia. Depletion of glyoxalase enzymes, GLO1 and GLO2, had minimal impact on KD-la, Kce, or hypoxia-induced KL-la. Conversely, blocking glycolytic flux to L-lactate under hypoxic conditions by knocking out lactate dehydrogenase A/B completely abolished the induction of KL-la but increased KD-la and Kce. We further observed a correlation between the level of KL-la and hypoxia-inducible factor 1 alpha (HIF-1α) expression under hypoxic conditions and when small molecules were used to stabilize HIF-1α in the normoxia condition. Our result demonstrated that there is a strong correlation between HIF-1α and KL-la in lung cancer tissues and that patient samples with higher grade tend to have higher KL-la levels. Using a proteomics approach, we quantified 66 KL-la sites that were up-regulated by hypoxia and demonstrated that p300/CBP contributes to hypoxia-induced KL-la. Collectively, our study demonstrates that KL-la, rather than KD-la or Kce, is the prevailing lysine lactylation in response to hypoxia. Our results therefore demonstrate a link between KL-la and the hypoxia-induced adaptation of tumor cells.

Keywords:  LC–MS/MS; hypoxia; lactylation; posttranslational modification (PTM)

DOI:  https://doi.org/10.1073/pnas.2404899122
bioRxiv. 2025 Feb 27. pii: 2025.02.26.640157. [Epub ahead of print]

Sphingolipid metabolism drives mitochondria remodeling during aging and oxidative stress.

Adam C Ebert, Nathaniel L Hepowit, Thyandra A Martinez, Henrik Vollmer, Hayley L Singkhek, Kyrie D Frazier, Sophia A Kantejeva, Maulik R Patel, Jason A MacGurn.

One of the hallmarks of aging is a decline in the function of mitochondria, which is often accompanied by altered morphology and dynamics. In some cases, these changes may reflect macromolecular damage to mitochondria that occurs with aging and stress, while in other cases they may be part of a programmed, adaptive response. In this study, we report that mitochondria undergo dramatic morphological changes in chronologically aged yeast cells. These changes are characterized by a large, rounded morphology, decreased co-localization of outer membrane and matrix markers, and decreased mitochondrial membrane potential. Notably, these transitions are prevented by pharmacological or genetic interventions that perturb sphingolipid biosynthesis, indicating that sphingolipids are required for these mitochondrial transitions in aging cells. Consistent with these findings, we observe that overexpression of inositol phospholipid phospholipase (Isc1) prevents these alterations to mitochondria morphology in aging cells. We also report that mitochondria exhibit similar sphingolipid-dependent morphological transitions following acute exposure to oxidative stress. These findings suggest that sphingolipid metabolism contributes to mitochondrial remodeling in aging cells and during oxidative stress, perhaps as a result of damaged sphingolipids that localize to mitochondrial membranes. These findings underscore the complex relationship between mitochondria function and sphingolipid metabolism, particularly in the context of aging and stress.

DOI: https://doi.org/10.1101/2025.02.26.640157
Nat Commun. 2025 Mar 07. 16(1): 2278

CYP51A1 drives resistance to pH-dependent cell death in pancreatic cancer.

Fangquan Chen, Hu Tang, Changfeng Li, Rui Kang, Daolin Tang, Jiao Liu.

Disrupted pH homeostasis can precipitate cell death and represents a viable therapeutic target in oncological interventions. Here, we utilize mass spectrometry-based drug analysis, transcriptomic screens, and lipid metabolomics to explore the metabolic mechanisms underlying pH-dependent cell death. We reveal CYP51A1, a gene involved in cholesterol synthesis, as a key suppressor of alkalization-induced cell death in pancreatic cancer cells. Inducing intracellular alkalization by the small molecule JTC801 leads to a decrease in endoplasmic reticulum cholesterol levels, subsequently activating SREBF2, a transcription factor responsible for controlling the expression of genes involved in cholesterol biosynthesis. Specifically, SREBF2-driven upregulation of CYP51A1 prevents cholesterol accumulation within lysosomes, leading to TMEM175-dependent lysosomal proton efflux, ultimately resulting in the inhibition of cell death. In animal models, including xenografts, syngeneic orthotopic, and patient-derived models, the genetic or pharmacological inhibition of CYP51A1 enhances the effectiveness of JTC801 in suppressing pancreatic tumors. These findings demonstrate a role of the CYP51A1-dependent lysosomal pathway in inhibiting alkalization-induced cell death and highlight its potential as a targetable vulnerability in pancreatic cancer.

DOI: https://doi.org/10.1038/s41467-025-57583-2
Front Cell Dev Biol. 2025 ;13 1535073

Targeting metabolic reprogramming in glioblastoma as a new strategy to overcome therapy resistance.

Simona D'Aprile, Simona Denaro, Anna Gervasi, Nunzio Vicario, Rosalba Parenti.

  Glioblastoma (GBM) is one of the deadliest tumors due to its high aggressiveness and resistance to standard therapies, resulting in a dismal prognosis. This lethal tumor carries out metabolic reprogramming in order to modulate specific pathways, providing metabolites that promote GBM cells proliferation and limit the efficacy of standard treatments. Indeed, GBM remodels glucose metabolism and undergoes Warburg effect, fuelling glycolysis even when oxygen is available. Moreover, recent evidence revealed a rewiring in nucleotide, lipid and iron metabolism, resulting not only in an increased tumor growth, but also in radio- and chemo-resistance. Thus, while on the one hand metabolic reprogramming is an advantage for GBM, on the other hand it may represent an exploitable target to hamper GBM progression. Lately, a number of studies focused on drugs targeting metabolism to uncover their effects on tumor proliferation and therapy resistance, demonstrating that some of these are effective, in combination with conventional treatments, sensitizing GBM to radiotherapy and chemotherapy. However, GBM heterogeneity could lead to a plethora of metabolic alterations among subtypes, hence a metabolic treatment might be effective for proneural tumors but not for mesenchymal ones, which are more aggressive and resistant to conventional approaches. This review explores key mechanisms of GBM metabolic reprogramming and their involvement in therapy resistance, highlighting how metabolism acts as a double-edged sword for GBM, taking into account metabolic pathways that seem to offer promising treatment options for GBM.

Keywords:  Warburg effect; chemotherapy; iron; lipids; metabolism; nucleotides; radiotherapy; tumor microenvironment

DOI:  https://doi.org/10.3389/fcell.2025.1535073
Anal Chem. 2025 Mar 13.

Time Series Imaging the Mitochondrial Microenvironment and Its Interactions with Lysosomes during Ferroptosis.

Xinyu Shao, Xusheng Ren, Tianshuo Xing, Xueying Zheng, Cuimin Feng, Tian Cheng, Junling Yin.

In the realm of cutting-edge scientific inquiry, the development and application of integrated optical molecular probes for the simultaneous detection and tracing of mitochondrial microenvironments during ferroptosis, as well as the visualization of their interactions with lysosomes, stands as a pivotal advancement. In this work, we developed a probe, IMT, that integrates viscosity sensing with mitochondrial targeting, and used it in conjunction with commercial lysosome green tracers (LGT) to investigate mitochondrial-lysosome interactions (MLIs). This approach avoids the uneven labeling caused by subcellular microenvironment differences when using single-molecule dual-targeting probes. Using the developed IMT, we observed an increase in mitochondrial viscosity during erastin-induced ferroptosis and a decrease during ferrostatin-1-inhibited ferroptosis. Moreover, the time series imaging of the mitochondrial profile lighted by the IMT showed that the mitochondrial area, perimeter, aspect ratio, and mitochondrial form factor changed significantly as ferroptosis progressed. In addition, combined with LGT, we visualized the dynamic process of first contact and then separation between lysosomes and mitochondria during ferroptosis, confirming the complexity and variability of MLIs. This work not only enhances our understanding of the complex biochemical processes underlying ferroptosis but also opens new avenues for therapeutic intervention in diseases characterized by this form of cell death.

DOI: https://doi.org/10.1021/acs.analchem.4c06840
J Vis Exp. 2025 Feb 21.

Measurement of Mitochondrial Membrane Potential In Vivo using a Genetically Encoded Voltage Indicator.

Run-Zhou Yang, Dian-Dian Wang, Sen-Miao Li, Pei-Pei Liu, Jian-Sheng Kang.

Mitochondrial membrane potential (MMP, ΔΨm) is critical for mitochondrial functions, including ATP synthesis, ion transport, reactive oxygen species (ROS) generation, and the import of proteins encoded by the nucleus. Existing methods for measuring ΔΨm typically use lipophilic cation dyes, such as Rhodamine 800 and tetramethylrhodamine methyl ester (TMRM), but these are limited by low specificity and are not well-suited for in vivo applications. To address these limitations, we have developed a novel protocol utilizing genetically encoded voltage indicators (GEVIs). Genetically encoded voltage indicators (GEVIs), which generate fluorescent signals in response to membrane potential changes, have demonstrated significant potential for monitoring plasma membrane and neuronal potentials. However, their application to mitochondrial membranes remains unexplored. Here, we developed protein-based mitochondrial-targeted GEVIs capable of detecting ΔΨm fluctuations in cells and the motor cortex of living animals. The mitochondrial potential indicator (MPI)offers a non-invasive approach to study ΔΨm dynamics in real-time, providing a method to investigate mitochondrial function under both normal and pathological conditions.

DOI: https://doi.org/10.3791/67911