bims-celmim 2024-09-08 papers

bims-celmim

Biomed News

on Cellular and mitochondrial metabolism

Issue of 2024–09–08
twenty-six papers selected by
Marc Segarra Mondejar

Multi-modal, Label-free, Optical Mapping of Cellular Metabolic Function and Oxidative Stress in 3D Engineered Brain Tissue Models.
Cytidine deaminase-dependent mitochondrial biogenesis as a potential vulnerability in pancreatic cancer cells.
SDHAF2 facilitates mitochondrial respiration through stabilizing succinate dehydrogenase and cytochrome c oxidase assemblies.
Proteo-metabolomics and patient tumor slice experiments point to amino acid centrality for rewired mitochondria in fibrolamellar carcinoma.
Mitochondrial dysfunction and increased reactive oxygen species production in MECP2 mutant astrocytes and their impact on neurons.
Allosteric Regulation of Pyruvate Kinase Enables Efficient and Robust Gluconeogenesis by Preventing Metabolic Conflicts and Carbon Overflow.
Real-time assessment of relative mitochondrial ATP synthesis response against inhibiting and stimulating substrates (MitoRAISE).
Pharmacologic LDH inhibition redirects intratumoral glucose uptake and improves antitumor immunity in solid tumor models.
Global 13C tracing and metabolic flux analysis of intact human liver tissue ex vivo.
The crosstalk between metabolism and translation.
Blood based metabolic markers of glioma from pre-diagnosis to surgery.
Genetically encoded fluorescent sensors for visualizing polyamine levels, uptake, and distribution.
Targeting amino acid-metabolizing enzymes for cancer immunotherapy.
Post-translational modifications of pyruvate dehydrogenase complex in cardiovascular disease.
Aldehyde dehydrogenase 2 preserves kidney function by countering acrolein-induced metabolic and mitochondrial dysfunction.
Single cell autofluorescence imaging reveals immediate metabolic shifts of neutrophils with activation across biological systems.
Understanding the interplay between dNTP metabolism and genome stability in cancer.
Immunometabolic effects of lactate on humoral immunity in healthy individuals of different ages.
SGLT2 inhibition mitigates transition from acute kidney injury to chronic kidney disease by suppressing ferroptosis.
Engineering signalling pathways in mammalian cells.
A Ketogenic Diet Sensitizes Pancreatic Cancer to Inhibition of Glutamine Metabolism.
Multiplex genome editing eliminates the Warburg Effect without impacting growth rate in mammalian cells.
Astrocyte involvement in metabolic regulation and disease.
A 2-hydroxybutyrate-mediated feedback loop regulates muscular fatigue.
Synthesis of non-canonical amino acids through dehydrogenative tailoring.
Metabolomic profiling identifies novel metabolites associated with cardiac dysfunction.

bioRxiv. 2024 Sep 02. pii: 2024.08.08.607216. [Epub ahead of print]

Multi-modal, Label-free, Optical Mapping of Cellular Metabolic Function and Oxidative Stress in 3D Engineered Brain Tissue Models.

Yang Zhang, Maria Savvidou, Volha Liaudanskaya, Varshini Ramanathan, Thi Bui, Lindley Matthew, Ash Sze, Ugochukwu Obinna Ugwu, Fu Yuhang, Dilsizian E Matthew, Xinjie Chen, Sevara Nasritdinova, Aonkon Dey, Eric L Miller, David L Kaplan, Irene Georgakoudi.

Brain metabolism is essential for the function of organisms. While established imaging methods provide valuable insights into brain metabolic function, they lack the resolution to capture important metabolic interactions and heterogeneity at the cellular level. Label-free, two-photon excited fluorescence imaging addresses this issue by enabling dynamic metabolic assessments at the single-cell level without manipulations. In this study, we demonstrate the impact of spectral imaging on the development of rigorous intensity and lifetime label-free imaging protocols to assess dynamically over time metabolic function in 3D engineered brain tissue models comprising human induced neural stem cells, astrocytes, and microglia. Specifically, we rely on multi-wavelength spectral imaging to identify the excitation/emission profiles of key cellular fluorophores within human brain cells, including NAD(P)H, LipDH, FAD, and lipofuscin. These enable development of methods to mitigate lipofuscin's overlap with NAD(P)H and flavin autofluorescence to extract reliable optical metabolic function metrics from images acquired at two excitation wavelengths over two emission bands. We present fluorescence intensity and lifetime metrics reporting on redox state, mitochondrial fragmentation, and NAD(P)H binding status in neuronal monoculture and triculture systems, to highlight the functional impact of metabolic interactions between different cell types. Our findings reveal significant metabolic differences between neurons and glial cells, shedding light on metabolic pathway utilization, including the glutathione pathway, OXPHOS, glycolysis, and fatty acid oxidation. Collectively, our studies establish a label-free, non-destructive approach to assess the metabolic function and interactions among different brain cell types relying on endogenous fluorescence and illustrate the complementary nature of information that is gained by combining intensity and lifetime-based images. Such methods can improve understanding of physiological brain function and dysfunction that occurs at the onset of cancers, traumatic injuries and neurodegenerative diseases.

DOI: https://doi.org/10.1101/2024.08.08.607216
Commun Biol. 2024 Aug 30. 7(1): 1065

Cytidine deaminase-dependent mitochondrial biogenesis as a potential vulnerability in pancreatic cancer cells.

Audrey Frances, Audrey Lumeau, Nicolas Bery, Marion Gayral, Lucille Stuani, Marie Sorbara, Estelle Saland, Delphine Pagan, Naïma Hanoun, Jérôme Torrisani, Anthony Lemarié, Jean-Charles Portais, Louis Buscail, Nelson Dusetti, Jean-Emmanuel Sarry, Pierre Cordelier.

Cytidine deaminase (CDA) converts cytidine and deoxycytidine into uridine and deoxyuridine as part of the pyrimidine salvage pathway. Elevated levels of CDA are found in pancreatic tumors and associated with chemoresistance. Recent evidence suggests that CDA has additional functions in cancer cell biology. In this work, we uncover a novel role of CDA in pancreatic cancer cell metabolism. CDA silencing impairs mitochondrial metabolite production, respiration, and ATP production in pancreatic cancer cells, leading to a so-called Pasteur effect metabolic shift towards glycolysis. Conversely, we find that CDA expression promotes mitochondrial biogenesis and oxidative phosphorylation, independently of CDA deaminase activity. Furthermore, we observe that patient primary cells overexpressing CDA are more sensitive to mitochondria-targeting drugs. Collectively, this work shows that CDA plays a non-canonical role in pancreatic cancer biology by promoting mitochondrial function, which could be translated into novel therapeutic vulnerabilities.

DOI: https://doi.org/10.1038/s42003-024-06760-y
Mitochondrion. 2024 Sep 03. pii: S1567-7249(24)00110-7. [Epub ahead of print]79 101952

SDHAF2 facilitates mitochondrial respiration through stabilizing succinate dehydrogenase and cytochrome c oxidase assemblies.

Chang-Lin Chen, Takaya Ishihara, Soumyadip Pal, Wei-Ling Huang, Emi Ogasawara, Chuang-Rung Chang, Naotada Ishihara.

  Succinate dehydrogenase (SDH) plays pivotal roles in maintaining cellular metabolism, modulating regulatory control over both the tricarboxylic acid cycle and oxidative phosphorylation to facilitate energy production within mitochondria. Given that SDH malfunction may serve as a hallmark triggering pseudo-hypoxia signaling and promoting tumorigenesis, elucidating the impact of SDH assembly defects on mitochondrial functions and cellular responses is of paramount importance. In this study, we aim to clarify the role of SDHAF2, one assembly factor of SDH, in mitochondrial respiratory activities. To achieve this, we utilize the CRISPR/Cas9 system to generate SDHAF2 knockout in HeLa cells and examine mitochondrial respiratory functions. Our findings demonstrate a substantial reduction in oxygen consumption rate in SDHAF2 knockout cells, akin to cells with inhibited SDH activity. In addition, in our in-gel activity assays reveal a significant decrease not only in SDH activity but also in cytochrome c oxidase (COX) activity in SDHAF2 knockout cells. The reduced COX activity is attributed to the assembly defect and remains independent of SDH inactivation or SDH complex disassembly. Together, our results indicate a critical role of SDHAF2 in regulating respiration by facilitating the assembly of COX.

Keywords:  Cytochrome c oxidase; Oxidative phosphorylation; Succinate dehydrogenase assembly factor 2 (SDHAF2)

DOI:  https://doi.org/10.1016/j.mito.2024.101952
Cell Rep Med. 2024 Aug 21. pii: S2666-3791(24)00420-8. [Epub ahead of print] 101699

Proteo-metabolomics and patient tumor slice experiments point to amino acid centrality for rewired mitochondria in fibrolamellar carcinoma.

Donald Long, Marina Chan, Mingqi Han, Zeal Kamdar, Rosanna K Ma, Pei-Yin Tsai, Adam B Francisco, Joeva Barrow, David B Shackelford, Mark Yarchoan, Matthew J McBride, Lukas M Orre, Nathaniel M Vacanti, Taranjit S Gujral, Praveen Sethupathy.

  Fibrolamellar carcinoma (FLC) is a rare, lethal, early-onset liver cancer with a critical need for new therapeutics. The primary driver in FLC is the fusion oncoprotein, DNAJ-PKAc, which remains challenging to target therapeutically. It is critical, therefore, to expand understanding of the FLC molecular landscape to identify druggable pathways/targets. Here, we perform the most comprehensive integrative proteo-metabolomic analysis of FLC. We also conduct nutrient manipulation, respirometry analyses, as well as key loss-of-function assays in FLC tumor tissue slices from patients. We propose a model of cellular energetics in FLC pointing to proline anabolism being mediated by ornithine aminotransferase hyperactivity and ornithine transcarbamylase hypoactivity with serine and glutamine catabolism fueling the process. We highlight FLC's potential dependency on voltage-dependent anion channel (VDAC), a mitochondrial gatekeeper for anions including pyruvate. The metabolic rewiring in FLC that we propose in our model, with an emphasis on mitochondria, can be exploited for therapeutic vulnerabilities.

Keywords:  alpha-ketoglutarate; fibrolamellar carcinoma; glucose; glutamine; metabolomics; mitochondria; proline; proteomics; pyruvate; serine

DOI:  https://doi.org/10.1016/j.xcrm.2024.101699
Sci Rep. 2024 09 04. 14(1): 20565

Mitochondrial dysfunction and increased reactive oxygen species production in MECP2 mutant astrocytes and their impact on neurons.

Danielle L Tomasello, M Inmaculada Barrasa, David Mankus, Katia I Alarcon, Abigail K R Lytton-Jean, X Shawn Liu, Rudolf Jaenisch.

  Studies on MECP2 function and its implications in Rett Syndrome (RTT) have traditionally centered on neurons. Here, using human embryonic stem cell (hESC) lines, we modeled MECP2 loss-of-function to explore its effects on astrocyte (AST) development and dysfunction in the brain. Ultrastructural analysis of RTT hESC-derived cerebral organoids revealed significantly smaller mitochondria compared to controls (CTRs), particularly pronounced in glia versus neurons. Employing a multiomics approach, we observed increased gene expression and accessibility of a subset of nuclear-encoded mitochondrial genes upon mutation of MECP2 in ASTs compared to neurons. Analysis of hESC-derived ASTs showed reduced mitochondrial respiration and altered key proteins in the tricarboxylic acid cycle and electron transport chain in RTT versus CTRs. Additionally, RTT ASTs exhibited increased cytosolic amino acids under basal conditions, which were depleted upon increased energy demands. Notably, mitochondria isolated from RTT ASTs exhibited increased reactive oxygen species and influenced neuronal activity when transferred to cortical neurons. These findings underscore MECP2 mutation's differential impact on mitochondrial and metabolic pathways in ASTs versus neurons, suggesting that dysfunctional AST mitochondria may contribute to RTT pathophysiology by affecting neuronal health.

Keywords:  Amino acid metabolism; Astrocyte; Electrophysiology; MECP2; Mitochondrial transplantation; Neurodevelopment; Rett syndrome; Single nuclei ATAC-seq; Single nuclei RNA-seq; Stem cells

DOI:  https://doi.org/10.1038/s41598-024-71040-y
bioRxiv. 2024 Aug 15. pii: 2024.08.15.607825. [Epub ahead of print]

Allosteric Regulation of Pyruvate Kinase Enables Efficient and Robust Gluconeogenesis by Preventing Metabolic Conflicts and Carbon Overflow.

Fukang She, Brent W Anderson, Daven B Khana, Shenwei Zhang, Wieland Steinchen, Danny K Fung, Lauren N Lucas, Nathalie G Lesser, David M Stevenson, Theresa J Astmann, Gert Bange, Jan-Peter van Pijkeren, Daniel Amador-Noguez, Jue D Wang.

Glycolysis and gluconeogenesis are reciprocal metabolic pathways that utilize different carbon sources. Pyruvate kinase catalyzes the irreversible final step of glycolysis, yet the physiological function of its regulation is poorly understood. Through metabolomics and enzyme kinetics studies, we discovered that pyruvate kinase activity is inhibited during gluconeogenesis in the soil bacterium Bacillus subtilis . This regulation involves an extra C-terminal domain (ECTD) of pyruvate kinase, which is essential for autoinhibition and regulation by metabolic effectors. Introducing a pyruvate kinase mutant lacking the ECTD into B. subtilis resulted in defects specifically under gluconeogenic conditions, including inefficient carbon utilization, slower growth, and decreased resistance to the herbicide glyphosate. These defects are not caused by the phosphoenolpyruvate-pyruvate-oxaloacetate futile cycle. Instead, we identified two significant metabolic consequences of pyruvate kinase dysregulation during gluconeogenesis: increased carbon overflow into the medium and failure to expand glycolytic intermediates such as phosphoenolpyruvate (PEP). In silico analysis revealed that in wild-type cells, an expanded PEP pool enabled by pyruvate kinase regulation is critical for the thermodynamic feasibility of gluconeogenesis. Our findings underscore the importance of allosteric regulation during gluconeogenesis in coordinating metabolic flux, efficient energy utilization, and antimicrobial resistance.

DOI: https://doi.org/10.1101/2024.08.15.607825
Cancer Metab. 2024 Aug 29. 12(1): 25

Real-time assessment of relative mitochondrial ATP synthesis response against inhibiting and stimulating substrates (MitoRAISE).

Eun Sol Chang, Kyoung Song, Ji-Young Song, Minjung Sung, Mi-Sook Lee, Jung Han Oh, Ji-Yeon Kim, Yeon Hee Park, Kyungsoo Jung, Yoon-La Choi.

   BACKGROUND: Mitochondria are known to synthesize adenosine triphosphate (ATP) through oxidative phosphorylation. Understanding and accurately measuring mitochondrial ATP synthesis rate can provide insights into the functional status of mitochondria and how it contributes to overall cellular energy homeostasis. Traditional methods only estimate mitochondrial function by measuring ATP levels at a single point in time or through oxygen consumption rates. This study introduced the relative mitochondrial ATP synthesis response against inhibiting and stimulating substrates (MitoRAISE), designed to detect real-time changes in ATP levels as the cells respond to substrates.
METHODS: The sensitivity and specificity of the MitoRAISE assay were verified under various conditions, including the isolation of mitochondria, variations in cell numbers, cells exhibiting mitochondrial damage, and heterogeneous mixtures. Using peripheral blood mononuclear cells (PBMCs), we analyzed MitoRAISE data from 19 patients with breast cancer and 23 healthy women.
RESULTS: The parameters observed in the MitoRAISE data increased depending on the quantity of isolated mitochondria and cell count, whereas it remained unmeasured in mitochondrial-damaged cell lines. Basal ATP, rotenone response, malonate response, and mitochondrial DNA copy numbers were lower in PBMCs from patients with breast cancer than in those from healthy women.
CONCLUSIONS: The MitoRAISE assay has demonstrated its sensitivity and specificity by measuring relative ATP synthesis rates under various conditions. We propose MitoRAISE assay as a potential tool for monitoring changes in the mitochondrial metabolic status associated with various diseases.

Keywords:  ATP; MitoRAISE; Mitochondrial function; Relative mitochondrial ATP synthesis rate; mtDNA copy number

DOI:  https://doi.org/10.1186/s40170-024-00353-3
J Clin Invest. 2024 Sep 03. pii: e177606. [Epub ahead of print]134(17):

Pharmacologic LDH inhibition redirects intratumoral glucose uptake and improves antitumor immunity in solid tumor models.

Svena Verma, Sadna Budhu, Inna Serganova, Lauren Dong, Levi M Mangarin, Jonathan F Khan, Mamadou A Bah, Anais Assouvie, Yacine Marouf, Isabell Schulze, Roberta Zappasodi, Jedd D Wolchok, Taha Merghoub.

  Tumor reliance on glycolysis is a hallmark of cancer. Immunotherapy is more effective in controlling glycolysis-low tumors lacking lactate dehydrogenase (LDH) due to reduced tumor lactate efflux and enhanced glucose availability within the tumor microenvironment (TME). LDH inhibitors (LDHi) reduce glucose uptake and tumor growth in preclinical models, but their impact on tumor-infiltrating T cells is not fully elucidated. Tumor cells have higher basal LDH expression and glycolysis levels compared with infiltrating T cells, creating a therapeutic opportunity for tumor-specific targeting of glycolysis. We demonstrate that LDHi treatment (a) decreases tumor cell glucose uptake, expression of the glucose transporter GLUT1, and tumor cell proliferation while (b) increasing glucose uptake, GLUT1 expression, and proliferation of tumor-infiltrating T cells. Accordingly, increasing glucose availability in the microenvironment via LDH inhibition leads to improved tumor-killing T cell function and impaired Treg immunosuppressive activity in vitro. Moreover, combining LDH inhibition with immune checkpoint blockade therapy effectively controls murine melanoma and colon cancer progression by promoting effector T cell infiltration and activation while destabilizing Tregs. Our results establish LDH inhibition as an effective strategy for rebalancing glucose availability for T cells within the TME, which can enhance T cell function and antitumor immunity.

Keywords:  Cancer immunotherapy; Glucose metabolism; Immunology; Metabolism; Pharmacology

DOI:  https://doi.org/10.1172/JCI177606
Nat Metab. 2024 Aug 29.

Global 13C tracing and metabolic flux analysis of intact human liver tissue ex vivo.

Nina Grankvist, Cecilia Jönsson, Karin Hedin, Nicolas Sundqvist, Per Sandström, Bergthor Björnsson, Arjana Begzati, Evgeniya Mickols, Per Artursson, Mohit Jain, Gunnar Cedersund, Roland Nilsson.

Liver metabolism is central to human physiology and influences the pathogenesis of common metabolic diseases. Yet, our understanding of human liver metabolism remains incomplete, with much of current knowledge based on animal or cell culture models that do not fully recapitulate human physiology. Here, we perform in-depth measurement of metabolism in intact human liver tissue ex vivo using global 13C tracing, non-targeted mass spectrometry and model-based metabolic flux analysis. Isotope tracing allowed qualitative assessment of a wide range of metabolic pathways within a single experiment, confirming well-known features of liver metabolism but also revealing unexpected metabolic activities such as de novo creatine synthesis and branched-chain amino acid transamination, where human liver appears to differ from rodent models. Glucose production ex vivo correlated with donor plasma glucose, suggesting that cultured liver tissue retains individual metabolic phenotypes, and could be suppressed by postprandial levels of nutrients and insulin, and also by pharmacological inhibition of glycogen utilization. Isotope tracing ex vivo allows measuring human liver metabolism with great depth and resolution in an experimentally tractable system.

DOI: https://doi.org/10.1038/s42255-024-01119-3
Cell Metab. 2024 Sep 03. pii: S1550-4131(24)00324-3. [Epub ahead of print]36(9): 1945-1962

The crosstalk between metabolism and translation.

Stefano Biffo, Davide Ruggero, Massimo Mattia Santoro.

  Metabolism and mRNA translation represent critical steps involved in modulating gene expression and cellular physiology. Being the most energy-consuming process in the cell, mRNA translation is strictly linked to cellular metabolism and in synchrony with it. Indeed, several mRNAs for metabolic pathways are regulated at the translational level, resulting in translation being a coordinator of metabolism. On the other hand, there is a growing appreciation for how metabolism impacts several aspects of RNA biology. For example, metabolic pathways and metabolites directly control the selectivity and efficiency of the translational machinery, as well as post-transcriptional modifications of RNA to fine-tune protein synthesis. Consistently, alterations in the intricate interplay between translational control and cellular metabolism have emerged as a critical axis underlying human diseases. A better understanding of such events will foresee innovative therapeutic strategies in human disease states.

Keywords:  disease; mRNA translation; metabolism; protein synthesis; signaling

DOI:  https://doi.org/10.1016/j.cmet.2024.07.022
Sci Rep. 2024 Sep 05. 14(1): 20680

Blood based metabolic markers of glioma from pre-diagnosis to surgery.

Sebastian Löding, Henrik Antti, Rickard L Sjöberg, Beatrice Melin, Benny Björkblom.

  Gliomas are highly complex and metabolically active brain tumors associated with poor prognosis. Recent reports have found altered levels of blood metabolites during early tumor development, suggesting that tumor development could be detected several years before clinical manifestation. In this study, we performed metabolite analyses of blood samples collected from healthy controls and future glioma patients, up to eight years before glioma diagnosis, and on the day of glioma surgery. We discovered that metabolites related to early glioma development were associated with an increased energy turnover, as highlighted by elevated levels of TCA-related metabolites such as fumarate, malate, lactate and pyruvate in pre-diagnostic cases. We also found that metabolites related to glioma progression at surgery were primarily high levels of amino acids and metabolites of amino acid catabolism, with elevated levels of 11 amino acids and two branched-chain alpha-ketoacids, ketoleucine and ketoisoleucine. High amino acid turnover in glioma tumor tissue is currently utilized for PET imaging, diagnosis and delineation of tumor margins. By examining blood-based metabolic progression patterns towards disease onset, we demonstrate that this high amino acid turnover is also detectable in a simple blood sample. These findings provide additional insight of metabolic alterations during glioma development and progression.

Keywords:  Blood metabolites; Early detection; Glioblastoma; Glioma; Liquid biopsy; Surgery

DOI:  https://doi.org/10.1038/s41598-024-71375-6
bioRxiv. 2024 Aug 22. pii: 2024.08.21.609037. [Epub ahead of print]

Genetically encoded fluorescent sensors for visualizing polyamine levels, uptake, and distribution.

Ryo Tamura, Jialin Chen, Marijke De Jaeger, Jacqueline F Morris, David A Scott, Peter Vangheluwe, Loren L Looger.

Polyamines are abundant and physiologically essential biomolecules that play a role in numerous processes, but are disrupted in diseases such as cancer, and cardiovascular and neurological disorders. Despite their importance, measuring free polyamine concentrations and monitoring their metabolism and uptake in cells in real-time remains impossible due to the lack of appropriate biosensors. Here we engineered, characterized, and validated the first genetically encoded biosensors for polyamines, named iPASnFRs. We demonstrate the utility of iPASnFR for detecting polyamine import into mammalian cells, to the cytoplasm, mitochondria, and the nucleus. We demonstrate that these sensors are useful to probe the activity of polyamine transporters and to uncover biochemical pathways underlying the distribution of polyamines amongst organelles. The sensors powered a high-throughput small molecule compound library screen, revealing multiple compounds in different chemical classes that strongly modulate cellular polyamine levels. These sensors will be powerful tools to investigate the complex interplay between polyamine uptake and metabolic pathways, address open questions about their role in health and disease, and enable screening for therapeutic polyamine modulators.

DOI: https://doi.org/10.1101/2024.08.21.609037
Front Immunol. 2024 ;15 1440269

Targeting amino acid-metabolizing enzymes for cancer immunotherapy.

Yvonne Grobben.

  Despite the immune system's role in the detection and eradication of abnormal cells, cancer cells often evade elimination by exploitation of various immune escape mechanisms. Among these mechanisms is the ability of cancer cells to upregulate amino acid-metabolizing enzymes, or to induce these enzymes in tumor-infiltrating immunosuppressive cells. Amino acids are fundamental cellular nutrients required for a variety of physiological processes, and their inadequacy can severely impact immune cell function. Amino acid-derived metabolites can additionally dampen the anti-tumor immune response by means of their immunosuppressive activities, whilst some can also promote tumor growth directly. Based on their evident role in tumor immune escape, the amino acid-metabolizing enzymes glutaminase 1 (GLS1), arginase 1 (ARG1), inducible nitric oxide synthase (iNOS), indoleamine 2,3-dioxygenase 1 (IDO1), tryptophan 2,3-dioxygenase (TDO) and interleukin 4 induced 1 (IL4I1) each serve as a promising target for immunotherapeutic intervention. This review summarizes and discusses the involvement of these enzymes in cancer, their effect on the anti-tumor immune response and the recent progress made in the preclinical and clinical evaluation of inhibitors targeting these enzymes.

Keywords:  IDO1; IL4I1; amino acid metabolism; arginine; cancer immunotherapy; glutamine; immunosuppression; tryptophan

DOI:  https://doi.org/10.3389/fimmu.2024.1440269
iScience. 2024 Sep 20. 27(9): 110633

Post-translational modifications of pyruvate dehydrogenase complex in cardiovascular disease.

Bo Guo, Fujiao Zhang, Yue Yin, Xingmin Ning, Zihui Zhang, Qinglei Meng, Ziqi Yang, Wenhua Jiang, Manling Liu, Yishi Wang, Lijuan Sun, Lu Yu, Nan Mu.

  Pyruvate dehydrogenase complex (PDC) is a crucial enzyme that connects glycolysis and the tricarboxylic acid (TCA) cycle pathway. It plays an essential role in regulating glucose metabolism for energy production by catalyzing the oxidative decarboxylation of pyruvate to acetyl coenzyme A. Importantly, the activity of PDC is regulated through post-translational modifications (PTMs), phosphorylation, acetylation, and O-GlcNAcylation. These PTMs have significant effects on PDC activity under both physiological and pathophysiological conditions, making them potential targets for metabolism-related diseases. This review specifically focuses on the PTMs of PDC in cardiovascular diseases (CVDs) such as myocardial ischemia/reperfusion injury, diabetic cardiomyopathy, obesity-related cardiomyopathy, heart failure (HF), and vascular diseases. The findings from this review offer theoretical references for the diagnosis, treatment, and prognosis of CVD.

Keywords:  Biochemistry; Cardiovascular medicine; Cell biology; Molecular biology

DOI:  https://doi.org/10.1016/j.isci.2024.110633
JCI Insight. 2024 Sep 03. pii: e179871. [Epub ahead of print]

Aldehyde dehydrogenase 2 preserves kidney function by countering acrolein-induced metabolic and mitochondrial dysfunction.

Szu-Yuan Li, Ming-Tsun Tsai, Yu-Ming Kuo, Hui-Min Yang, Zhen-Jie Tong, Hsiao-Wei Cheng, Chih-Ching Lin, Hsiang-Tsui Wang.

  The prevalence of chronic kidney diseases (CKD) varies by race due to genetic and environmental factors. The Glu504Lys polymorphism in aldehyde dehydrogenase 2 (ALDH2), commonly observed among East Asians, alters the enzyme's function in detoxifying alcohol-derived aldehydes, impacting kidney function. This study investigated the association between variations in ALDH2 levels within the kidney and the progression of kidney fibrosis. Our clinical data indicates that diminished ALDH2 levels are linked to worse CKD outcomes, with correlations between ALDH2 expression, estimated glomerular filtration rate, urinary levels of acrolein, an aldehyde metabolized by ALDH2, and fibrosis severity. In mouse models of unilateral ureteral obstruction and folic acid nephropathy, reduced ALDH2 levels and elevated acrolein were observed in kidneys, especially in ALDH2 Glu504Lys knock-in mice. Mechanistically, acrolein modifies pyruvate kinase M2, leading to its nuclear translocation and co-activation of HIF-1α, shifting cellular metabolism to glycolysis, disrupting mitochondrial function, contributing to tubular damage and the progression of kidney fibrosis. Enhancing ALDH2 expression through adeno-associated virus vectors reduces acrolein and mitigates fibrosis in both wild-type and Glu504Lys knock-in mice. These findings underscore the potential therapeutic significance of targeting the dynamic interaction between ALDH2 and acrolein in CKD.

Keywords:  Chronic kidney disease; Fibrosis; Metabolism; Mitochondria; Nephrology

DOI:  https://doi.org/10.1172/jci.insight.179871
bioRxiv. 2024 Jul 29. pii: 2024.07.26.605362. [Epub ahead of print]

Single cell autofluorescence imaging reveals immediate metabolic shifts of neutrophils with activation across biological systems.

Rupsa Datta, Veronika Miskolci, Gina M Gallego-López, Emily Britt, Amani Gillette, Aleksandr Kralovec, Morgan A Giese, Tongcheng Qian, Jing Fan, Anna Huttenlocher, Melissa C Skala.

Neutrophils, the most abundant leukocytes in human peripheral circulation, are crucial for the innate immune response. They are typically quiescent but rapidly activate in response to infection and inflammation, performing diverse functions such as oxidative burst, phagocytosis, and NETosis, which require significant metabolic adaptation. Deeper insights into such metabolic changes will help identify regulation of neutrophil functions in health and diseases. Due to their short lifespan and associated technical challenges, the metabolic processes of neutrophils are not completely understood. This study uses optical metabolic imaging (OMI), which entails optical redox ratio and fluorescence lifetime imaging microscopy of intrinsic metabolic coenzymes NAD(P)H and FAD to assess the metabolic state of single neutrophils. Primary human neutrophils were imaged in vitro under a variety of activation conditions and metabolic pathway inhibitors, while metabolic and functional changes were confirmed with mass spectrometry, oxidative burst, and NETosis measurements. Our findings show that neutrophils undergo rapid metabolic remodeling to a reduced redox state, followed by a shift to an oxidized redox state during activation. Additionally, single cell analysis reveals a heterogeneous metabolic response across neutrophils and donors to live pathogen infection ( Pseudomonas aeruginosa and Toxoplasma gondii ). Finally, consistent metabolic changes were validated with neutrophils in vivo using zebrafish larvae. This study demonstrates the potential of OMI as a versatile tool for studying neutrophil metabolism and underscores its use across different biological systems, offering insights into neutrophil metabolic activity and function at a single cell level.

DOI: https://doi.org/10.1101/2024.07.26.605362
Dis Model Mech. 2024 Aug 01. pii: dmm050775. [Epub ahead of print]17(8):

Understanding the interplay between dNTP metabolism and genome stability in cancer.

Miriam Yagüe-Capilla, Sean G Rudd.

  The size and composition of the intracellular DNA precursor pool is integral to the maintenance of genome stability, and this relationship is fundamental to our understanding of cancer. Key aspects of carcinogenesis, including elevated mutation rates and induction of certain types of DNA damage in cancer cells, can be linked to disturbances in deoxynucleoside triphosphate (dNTP) pools. Furthermore, our approaches to treat cancer heavily exploit the metabolic interplay between the DNA and the dNTP pool, with a long-standing example being the use of antimetabolite-based cancer therapies, and this strategy continues to show promise with the development of new targeted therapies. In this Review, we compile the current knowledge on both the causes and consequences of dNTP pool perturbations in cancer cells, together with their impact on genome stability. We outline several outstanding questions remaining in the field, such as the role of dNTP catabolism in genome stability and the consequences of dNTP pool expansion. Importantly, we detail how our mechanistic understanding of these processes can be utilised with the aim of providing better informed treatment options to patients with cancer.

Keywords:  Cancer; DNA repair; Deoxynucleoside triphosphate (dNTP) metabolism; Genome stability

DOI:  https://doi.org/10.1242/dmm.050775
Nat Commun. 2024 Aug 30. 15(1): 7515

Immunometabolic effects of lactate on humoral immunity in healthy individuals of different ages.

Maria Romero, Kate Miller, Andrew Gelsomini, Denisse Garcia, Kevin Li, Dhananjay Suresh, Daniela Frasca.

Aging is characterized by chronic systemic inflammation and metabolic changes. We compare the metabolic status of B cells from young and elderly donors and found that aging is associated with higher oxygen consumption rates, and especially higher extracellular acidification rates, measures of oxidative phosphorylation and of anaerobic glycolysis, respectively. Importantly, this higher metabolic status, which reflects age-associated expansion of pro-inflammatory B cells, is found associated with higher secretion of lactate and autoimmune antibodies after in vitro stimulation. B cells from elderly individuals induce in vitro polarization of CD4+ T cells from young individuals into pro-inflammatory CD4+ T cells through metabolic pathways mediated by lactate, which can be inhibited by targeting lactate enzymes and transporters, as well as signaling pathways supporting anaerobic glycolysis. Lactate also induces immunosenescent B cells that are glycolytic, express transcripts for multiple pro-inflammatory molecules, and are characterized by a higher metabolic status. These results altogether may have relevant clinical implications and suggest alternative targets for therapeutic interventions in the elderly and patients with inflammatory conditions and diseases.

DOI: https://doi.org/10.1038/s41467-024-51207-x
Sci Rep. 2024 09 02. 14(1): 20386

SGLT2 inhibition mitigates transition from acute kidney injury to chronic kidney disease by suppressing ferroptosis.

Yutaro Hirashima, Toshiaki Nakano, Kumiko Torisu, Seishi Aihara, Masanori Wakisaka, Takanari Kitazono.

  Sodium-glucose cotransporter 2 (SGLT2) inhibitors have been shown to be renoprotective in ischemia-reperfusion (I/R) injury, with several proposed mechanisms, though additional mechanisms likely exist. This study investigated the impact of luseogliflozin on kidney fibrosis at 48 h and 1 week post I/R injury in C57BL/6 mice. Luseogliflozin attenuated kidney dysfunction and the acute tubular necrosis score on day 2 post I/R injury, and subsequent fibrosis at 1 week, as determined by Sirius red staining. Metabolomics enrichment analysis of I/R-injured kidneys revealed suppression of the glycolytic system and activation of mitochondrial function under treatment with luseogliflozin. Western blotting showed increased nutrient deprivation signaling with elevated phosphorylated AMP-activated protein kinase and Sirtuin-3 in luseogliflozin-treated kidneys. Luseogliflozin-treated kidneys displayed increased protein levels of carnitine palmitoyl transferase 1α and decreased triglyceride deposition, as determined by oil red O staining, suggesting activated fatty acid oxidation. Luseogliflozin prevented the I/R injury-induced reduction in nuclear factor erythroid 2-related factor 2 activity. Western blotting revealed increased glutathione peroxidase 4 and decreased transferrin receptor protein 1 expression. Immunostaining showed reduced 4-hydroxynonenal and malondialdehyde levels, especially in renal tubules, indicating suppressed ferroptosis. Luseogliflozin may protect the kidney from I/R injury by inhibiting ferroptosis through oxidative stress reduction.

Keywords:  Ferroptosis; Ischemia reperfusion injury; Luseogliflozin; Nrf2

DOI:  https://doi.org/10.1038/s41598-024-71416-0
Nat Biomed Eng. 2024 Sep 05.

Engineering signalling pathways in mammalian cells.

Anna V Leopold, Vladislav V Verkhusha.

In mammalian cells, signalling pathways orchestrate cellular growth, differentiation and survival, as well as many other processes that are essential for the proper functioning of cells. Here we describe cutting-edge genetic-engineering technologies for the rewiring of signalling networks in mammalian cells. Specifically, we describe the recombination of native pathway components, cross-kingdom pathway transplantation, and the development of de novo signalling within cells and organelles. We also discuss how, by designing signalling pathways, mammalian cells can acquire new properties, such as the capacity for photosynthesis, the ability to detect cancer and senescent cell markers or to synthesize hormones or metabolites in response to chemical or physical stimuli. We also review the applications of mammalian cells in biocomputing. Technologies for engineering signalling pathways in mammalian cells are advancing basic cellular biology, biomedical research and drug discovery.

DOI: https://doi.org/10.1038/s41551-024-01237-z
bioRxiv. 2024 Jul 23. pii: 2024.07.19.604377. [Epub ahead of print]

A Ketogenic Diet Sensitizes Pancreatic Cancer to Inhibition of Glutamine Metabolism.

Omid Hajihassani, Mehrdad Zarei, Asael Roichman, Alexander Loftus, Christina S Boutros, Jonathan Hue, Parnian Naji, Jacob Boyer, Soubhi Tahan, Peter Gallagher, William Beegan, James Choi, Shihong Lei, Christine Kim, Moeez Rathore, Faith Nakazzi, Ishan Shah, Kevin Lebo, Helen Cheng, Anusha Mudigonda, Sydney Alibeckoff, Karen Ji, Hallie Graor, Masaru Miyagi, Ali Vaziri-Gohar, Henri Brunengraber, Rui Wang, Peder J Lund, Luke D Rothermel, Joshua D Rabinowitz, Jordan M Winter.

Pancreatic cancer is the third leading cause of cancer death in the United States, and while conventional chemotherapy remains the standard treatment, responses are poor. Safe and alternative therapeutic strategies are urgently needed 1 . A ketogenic diet has been shown to have anti-tumor effects across diverse cancer types but will unlikely have a significant effect alone. However, the diet shifts metabolism in tumors to create new vulnerabilities that can be targeted (1). Modulators of glutamine metabolism have shown promise in pre-clinical models but have failed to have a marked impact against cancer in the clinic. We show that a ketogenic diet increases TCA and glutamine-associated metabolites in murine pancreatic cancer models and under metabolic conditions that simulate a ketogenic diet in vitro. The metabolic shift leads to increased reliance on glutamine-mediated anaplerosis to compensate for low glucose abundance associated with a ketogenic diet. As a result, glutamine metabolism inhibitors, such as DON and CB839 in combination with a ketogenic diet had robust anti-cancer effects. These findings provide rationale to study the use of a ketogenic diet with glutamine targeted therapies in a clinical context.

DOI: https://doi.org/10.1101/2024.07.19.604377
bioRxiv. 2024 Aug 06. pii: 2024.08.02.606284. [Epub ahead of print]

Multiplex genome editing eliminates the Warburg Effect without impacting growth rate in mammalian cells.

Hooman Hefzi, Iván Martínez-Monge, Igor Marin de Mas, Nicholas Luke Cowie, Alejandro Gomez Toledo, Soo Min Noh, Karen Julie la Cour Karottki, Marianne Decker, Johnny Arnsdorf, Jose Manuel Camacho-Zaragoza, Stefan Kol, Sanne Schoffelen, Nuša Pristovšek, Anders Holmgaard Hansen, Antonio A Miguez, Sara Petersen Bjorn, Karen Kathrine Brøndum, Elham Maria Javidi, Kristian Lund Jensen, Laura Stangl, Emanuel Kreidl, Thomas Beuchert Kallehauge, Daniel Ley, Patrice Ménard, Helle Munck Petersen, Zulfiya Sukhova, Anton Bauer, Emilio Casanova, Niall Barron, Johan Malmström, Lars K Nielsen, Gyun Min Lee, Helene Faustrup Kildegaard, Bjørn G Voldborg, Nathan E Lewis.

The Warburg effect is ubiquitous in proliferative mammalian cells, including cancer cells, but poses challenges for biopharmaceutical production, as lactate accumulation inhibits cell growth and protein production. Previous efforts to eliminate lactate production via knockout have failed in mammalian bioprocessing since lactate dehydrogenase has proven essential. However, here we eliminated the Warburg effect in Chinese hamster ovary (CHO) and HEK293 cells by simultaneously knocking out lactate dehydrogenase and regulators involved in a negative feedback loop that typically inhibits pyruvate conversion to acetyl-CoA. In contrast to long-standing assumptions about the role of aerobic glycolysis, Warburg-null cells maintain wildtype growth rate while producing negligible lactate. Further characterization of Warburg-null CHO cells showed a compensatory increase in oxygen consumption, a near total reliance on oxidative metabolism, and higher cell densities in fed-batch cell culture. These cells remained amenable for production of diverse biotherapeutic proteins, reaching industrially relevant titers and maintaining product glycosylation. Thus, the ability to eliminate the Warburg effect is an important development for biotherapeutic production and provides a tool for investigating a near-universal metabolic phenomenon.

DOI: https://doi.org/10.1101/2024.08.02.606284
Trends Endocrinol Metab. 2024 Aug 29. pii: S1043-2760(24)00220-0. [Epub ahead of print]

Astrocyte involvement in metabolic regulation and disease.

Muhammad Naveed, Kathryn Smedlund, Qi-Gang Zhou, Weikang Cai, Jennifer W Hill.

  Astrocytes, the predominant glial cell type in the mammalian brain, influence a wide variety of brain parameters including neuronal energy metabolism. Exciting recent studies have shown that obesity and diabetes can impact on astrocyte function. We review evidence that dysregulation of astrocytic lipid metabolism and glucose sensing contributes to dysregulation of whole-body energy balance, thermoregulation, and insulin sensitivity. In addition, we consider the overlooked topic of the sex-specific roles of astrocytes and their response to hormonal fluctuations that provide insights into sex differences in metabolic regulation. Finally, we provide an update on potential ways to manipulate astrocyte function, including genetic targeting, optogenetic and chemogenetic techniques, transplantation, and tailored exosome-based therapies, which may lead to improved treatments for metabolic disease.

Keywords:  astrocytes; diabetes; metabolic disease; obesity; sex-specific

DOI:  https://doi.org/10.1016/j.tem.2024.08.001
Elife. 2024 Sep 03. pii: RP92707. [Epub ahead of print]12

A 2-hydroxybutyrate-mediated feedback loop regulates muscular fatigue.

Brennan J Wadsworth, Marina Leiwe, Eleanor A Minogue, Pedro P Cunha, Viktor Engman, Carolin Brombach, Christos Asvestis, Shiv K Sah-Teli, Emilia Marklund, Peppi Karppinen, Jorge L Ruas, Helene Rundqvist, Johanna T Lanner, Randall S Johnson.

  Several metabolites have been shown to have independent and at times unexpected biological effects outside of their metabolic pathways. These include succinate, lactate, fumarate, and 2-hydroxyglutarate. 2-Hydroxybutyrate (2HB) is a byproduct of endogenous cysteine synthesis, produced during periods of cellular stress. 2HB rises acutely after exercise; it also rises during infection and is also chronically increased in a number of metabolic disorders. We show here that 2HB inhibits branched-chain aminotransferase enzymes, which in turn triggers a SIRT4-dependent shift in the compartmental abundance of protein ADP-ribosylation. The 2HB-induced decrease in nuclear protein ADP-ribosylation leads to a C/EBPβ-mediated transcriptional response in the branched-chain amino acid degradation pathway. This response to 2HB exposure leads to an improved oxidative capacity in vitro. We found that repeated injection with 2HB can replicate the improvement to oxidative capacity that occurs following exercise training. Together, we show that 2-HB regulates fundamental aspects of skeletal muscle metabolism.

Keywords:  Exercise; biochemistry; chemical biology; metabolite; mouse; muscle fiber

DOI:  https://doi.org/10.7554/eLife.92707
Nature. 2024 Aug 29.

Synthesis of non-canonical amino acids through dehydrogenative tailoring.

Xin Gu, Yu-An Zhang, Shuo Zhang, Leon Wang, Xiyun Ye, Gino Occhialini, Jonah Barbour, Bradley L Pentelute, Alison E Wendlandt.

Amino acids are essential building blocks in biology and chemistry. While nature relies on a small number of amino acid structures, chemists desire access to a vast scope of structurally diverse analogs1-3 The selective modification of amino acid side-chain residues represents an efficient strategy to access non-canonical derivatives of value in chemistry and biology. While semi-synthetic methods leveraging the functional groups found in polar and aromatic amino acids have been extensively explored, highly selective and general approaches to transform unactivated C-H bonds in aliphatic amino acids remain less developed4,5 Here, we disclose a stepwise dehydrogenative method to convert aliphatic amino acids into structurally diverse analogs. The key to the success of this approach lies in the development of a selective catalytic acceptorless dehydrogenation method driven by photochemical irradiation, which provides access to terminal alkene intermediates for downstream functionalization. Overall, this strategy enables the rapid synthesis of new amino acid building blocks and suggests possibilities for the late-stage modification of more complex oligopeptides.

DOI: https://doi.org/10.1038/s41586-024-07988-8
Sci Rep. 2024 Sep 05. 14(1): 20694

Metabolomic profiling identifies novel metabolites associated with cardiac dysfunction.

Kasen L Culler, Arjun Sinha, Mallory Filipp, Pedro Giro, Norrina B Allen, Kent D Taylor, Xiuqing Guo, Ed Thorp, Benjamin H Freed, Philip Greenland, Wendy S Post, Alain Bertoni, David Herrington, Chen Gao, Yibin Wang, Sanjiv J Shah, Ravi B Patel.

  Metabolic comorbidities, such as obesity and diabetes, are associated with subclinical alterations in both cardiac structure/function and natriuretic peptides prior to the onset of heart failure (HF). Despite this, the exact metabolic pathways of cardiac dysfunction which precede HF are not well-defined. Among older individuals without HF in the Multi-Ethnic Study of Atherosclerosis (MESA), we evaluated the associations of 47 circulating metabolites measured by 1H-NMR with echocardiographic measures of cardiac structure and function. We then evaluated associations of significant metabolites with circulating N-terminal pro-B-type natriuretic peptide (NT-proBNP). In a separate cohort, we evaluated differences between top metabolites in patients with HF with preserved ejection fraction (HFpEF) and comorbidity-matched controls. Genetic variants associated with top metabolites (mQTLs) were then related to echocardiographic measures and NT-proBNP. Among 3440 individuals with metabolic and echocardiographic data in MESA (62 ± 10 years, 52% female, 38% White), 10 metabolites broadly reflective of glucose and amino acid metabolism were associated with at least 1 measure of cardiac structure or function. Of these 10 metabolites, 4 (myo-inositol, glucose, dimethylsulfone, carnitine) were associated with higher NT-proBNP and 2 (d-mannose, acetone) were associated with lower NT-proBNP. In a separate cohort, patients with HFpEF had higher circulating myo-inositol levels compared with comorbidity-matched controls. Genetic analyses revealed that 1 of 6 known myo-inositol mQTLs conferred risk of higher NT-proBNP. In conclusion, metabolomic profiling identifies several novel metabolites associated with cardiac dysfunction in a cohort at high risk for HF, revealing pathways potentially relevant to future HF risk.

Keywords:  Cardiac structure; Echocardiography; Genetics; Heart failure; Metabolomics; Myo-inositol; Natriuretic peptide

DOI:  https://doi.org/10.1038/s41598-024-71329-y