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McMullen E, Hertenstein H, Strassburger K, Deharde L, Brankatschk M, Schirmeier S. Glycolytically impaired Drosophila glial cells fuel neural metabolism via β-oxidation. Nat Commun 2023; 14:2996. [PMID: 37225684 DOI: 10.1038/s41467-023-38813-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/17/2023] [Indexed: 05/26/2023] Open
Abstract
Neuronal function is highly energy demanding and thus requires efficient and constant metabolite delivery by glia. Drosophila glia are highly glycolytic and provide lactate to fuel neuronal metabolism. Flies are able to survive for several weeks in the absence of glial glycolysis. Here, we study how Drosophila glial cells maintain sufficient nutrient supply to neurons under conditions of impaired glycolysis. We show that glycolytically impaired glia rely on mitochondrial fatty acid breakdown and ketone body production to nourish neurons, suggesting that ketone bodies serve as an alternate neuronal fuel to prevent neurodegeneration. We show that in times of long-term starvation, glial degradation of absorbed fatty acids is essential to ensure survival of the fly. Further, we show that Drosophila glial cells act as a metabolic sensor and can induce mobilization of peripheral lipid stores to preserve brain metabolic homeostasis. Our study gives evidence of the importance of glial fatty acid degradation for brain function, and survival, under adverse conditions in Drosophila.
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Affiliation(s)
- Ellen McMullen
- Department of Molecular Biology and Genetics, University of South Bohemia, České Budějovice, Czech Republic
| | - Helen Hertenstein
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| | - Katrin Strassburger
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| | - Leon Deharde
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| | - Marko Brankatschk
- Biotechnologisches Zentrum, Technische Universität Dresden, Dresden, Germany.
| | - Stefanie Schirmeier
- Zoology and Animal Physiology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany.
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2
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Aburto C, Galaz A, Bernier A, Sandoval PY, Holtheuer-Gallardo S, Ruminot I, Soto-Ojeda I, Hertenstein H, Schweizer JA, Schirmeier S, Pástor TP, Mardones GA, Barros LF, San Martín A. Single-Fluorophore Indicator to Explore Cellular and Sub-cellular Lactate Dynamics. ACS Sens 2022; 7:3278-3286. [PMID: 36306435 DOI: 10.1021/acssensors.2c00731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lactate is an energy substrate and an intercellular signal, which can be monitored in intact cells with the genetically encoded FRET indicator Laconic. However, the structural complexity, need for sophisticated equipment, and relatively small fluorescent change limit the use of FRET indicators for subcellular targeting and development of high-throughput screening methodologies. Using the bacterial periplasmic binding protein TTHA0766 from Thermus thermophilus, we have now developed a single-fluorophore indicator for lactate, CanlonicSF. This indicator exhibits a maximal fluorescence change of 200% and a KD of ∼300 μM. The fluorescence is not affected by other monocarboxylates. The lactate indicator was not significantly affected by Ca2+ at the physiological concentrations prevailing in the cytosol, endoplasmic reticulum, and extracellular space, but was affected by Ca2+ in the low micromolar range. Targeting the indicator to the endoplasmic reticulum revealed for the first time sub-cellular lactate dynamics. Its improved lactate-induced fluorescence response permitted the development of a multiwell plate assay to screen for inhibitors of the monocarboxylate transporters MCTs, a pharmaceutical target for cancer and inflammation. The functionality of the indicator in living tissue was demonstrated in the brain of Drosophila melanogaster larvae. CanlonicSF is well suited to explore lactate dynamics with sub-cellular resolution in intact systems.
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Affiliation(s)
- Camila Aburto
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Universidad Austral de Chile, Isla Teja s/n, Postal Code 5110566 Valdivia, Chile
| | - Alex Galaz
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile
| | - Angelo Bernier
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Universidad Austral de Chile, Isla Teja s/n, Postal Code 5110566 Valdivia, Chile
| | - Pamela Yohana Sandoval
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Postal Code 5110773 Valdivia, Chile
| | - Sebastián Holtheuer-Gallardo
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Universidad Austral de Chile, Isla Teja s/n, Postal Code 5110566 Valdivia, Chile
| | - Iván Ruminot
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Postal Code 5110773 Valdivia, Chile
| | - Ignacio Soto-Ojeda
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Universidad Austral de Chile, Isla Teja s/n, Postal Code 5110566 Valdivia, Chile
| | - Helen Hertenstein
- Department of Biology, Technische Universität Dresden, Postal Code 01062 Dresden, Germany
| | | | - Stefanie Schirmeier
- Department of Biology, Technische Universität Dresden, Postal Code 01062 Dresden, Germany
| | - Tammy Paulina Pástor
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Isla Teja s/n, Postal Code 5110566 Valdivia, Chile
| | - Gonzalo Antonio Mardones
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Isla Teja s/n, Postal Code 5110566 Valdivia, Chile
| | - Luis Felipe Barros
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Postal Code 5110773 Valdivia, Chile
| | - Alejandro San Martín
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Postal Code 5110466 Valdivia, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Postal Code 5110773 Valdivia, Chile
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McMullen E, Hertenstein H, Müller S, Schirmeier S. Genetically Encoded Sensors to Study Metabolism in Drosophila. Methods Mol Biol 2022; 2540:401-414. [PMID: 35980591 DOI: 10.1007/978-1-0716-2541-5_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The rather recent development of genetically encoded metabolite sensors has changed the way we can study metabolism in living cells, ex vivo tissues, and in vivo immensely. In recent years, these sensors have also been adapted for use in Drosophila tissues. Here, we describe a standard protocol to image such sensors in ex vivo Drosophila larval brains using the glucose sensor FLII12Pglu-700μδ6. The protocol, however, can be adapted for the use of other sensors, tissues, and can even be used in vivo.
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Affiliation(s)
- Ellen McMullen
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Helen Hertenstein
- Department of Biology, Institute of Zoology, Technische Universität Dresden, Dresden, Germany
| | - Stephan Müller
- Department of Biology, Institute of Zoology, Technische Universität Dresden, Dresden, Germany
| | - Stefanie Schirmeier
- Department of Biology, Institute of Zoology, Technische Universität Dresden, Dresden, Germany.
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Hertenstein H, McMullen E, Weiler A, Volkenhoff A, Becker HM, Schirmeier S. Starvation-induced regulation of carbohydrate transport at the blood-brain barrier is TGF-β-signaling dependent. eLife 2021; 10:e62503. [PMID: 34032568 PMCID: PMC8149124 DOI: 10.7554/elife.62503] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 04/13/2021] [Indexed: 12/15/2022] Open
Abstract
During hunger or malnutrition, animals prioritize alimentation of the brain over other organs to ensure its function and, thus, their survival. This protection, also-called brain sparing, is described from Drosophila to humans. However, little is known about the molecular mechanisms adapting carbohydrate transport. Here, we used Drosophila genetics to unravel the mechanisms operating at the blood-brain barrier (BBB) under nutrient restriction. During starvation, expression of the carbohydrate transporter Tret1-1 is increased to provide more efficient carbohydrate uptake. Two mechanisms are responsible for this increase. Similar to the regulation of mammalian GLUT4, Rab-dependent intracellular shuttling is needed for Tret1-1 integration into the plasma membrane; even though Tret1-1 regulation is independent of insulin signaling. In addition, starvation induces transcriptional upregulation that is controlled by TGF-β signaling. Considering TGF-β-dependent regulation of the glucose transporter GLUT1 in murine chondrocytes, our study reveals an evolutionarily conserved regulatory paradigm adapting the expression of sugar transporters at the BBB.
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Affiliation(s)
- Helen Hertenstein
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
| | - Ellen McMullen
- Institut für Neuro- und Verhaltensbiologie, WWU MünsterMünsterGermany
| | - Astrid Weiler
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
| | - Anne Volkenhoff
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
| | - Holger M Becker
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
- Division of General Zoology, Department of Biology, University of KaiserslauternKaiserslauternGermany
| | - Stefanie Schirmeier
- Department of Biology, Institute of Zoology, Technische Universität DresdenDresdenGermany
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Sorge S, Theelke J, Yildirim K, Hertenstein H, McMullen E, Müller S, Altbürger C, Schirmeier S, Lohmann I. ATF4-Induced Warburg Metabolism Drives Over-Proliferation in Drosophila. Cell Rep 2021; 31:107659. [PMID: 32433968 DOI: 10.1016/j.celrep.2020.107659] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 01/30/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022] Open
Abstract
The mitochondrial electron transport chain (ETC) enables essential metabolic reactions; nonetheless, the cellular responses to defects in mitochondria and the modulation of signaling pathway outputs are not understood. We show that Notch signaling and ETC attenuation via knockdown of COX7a induces massive over-proliferation. The tumor-like growth is caused by a transcriptional response through the eIF2α-kinase PERK and ATF4, which activates the expression of metabolic enzymes, nutrient transporters, and mitochondrial chaperones. We find this stress adaptation to be beneficial for progenitor cell fitness, as it renders cells sensitive to proliferation induced by the Notch signaling pathway. Intriguingly, over-proliferation is not caused by transcriptional cooperation of Notch and ATF4, but it is mediated in part by pH changes resulting from the Warburg metabolism induced by ETC attenuation. Our results suggest that ETC function is monitored by the PERK-ATF4 pathway, which can be hijacked by growth-promoting signaling pathways, leading to oncogenic pathway activity.
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Affiliation(s)
- Sebastian Sorge
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Jonas Theelke
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Kerem Yildirim
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Helen Hertenstein
- Institute of Neuro- and Behavioral Biology, University of Münster, 48149 Münster, Germany
| | - Ellen McMullen
- Institute of Neuro- and Behavioral Biology, University of Münster, 48149 Münster, Germany
| | - Stephan Müller
- Institute of Neuro- and Behavioral Biology, University of Münster, 48149 Münster, Germany
| | | | - Stefanie Schirmeier
- Institute of Neuro- and Behavioral Biology, University of Münster, 48149 Münster, Germany
| | - Ingrid Lohmann
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg University, 69120 Heidelberg, Germany.
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6
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Weiler A, Volkenhoff A, Hertenstein H, Schirmeier S. Metabolite transport across the mammalian and insect brain diffusion barriers. Neurobiol Dis 2017; 107:15-31. [PMID: 28237316 DOI: 10.1016/j.nbd.2017.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 01/02/2017] [Accepted: 02/20/2017] [Indexed: 12/31/2022] Open
Abstract
The nervous system in higher vertebrates is separated from the circulation by a layer of specialized endothelial cells. It protects the sensitive neurons from harmful blood-derived substances, high and fluctuating ion concentrations, xenobiotics or even pathogens. To this end, the brain endothelial cells and their interlinking tight junctions build an efficient diffusion barrier. A structurally analogous diffusion barrier exists in insects, where glial cell layers separate the hemolymph from the neural cells. Both types of diffusion barriers, of course, also prevent influx of metabolites from the circulation. Because neuronal function consumes vast amounts of energy and necessitates influx of diverse substrates and metabolites, tightly regulated transport systems must ensure a constant metabolite supply. Here, we review the current knowledge about transport systems that carry key metabolites, amino acids, lipids and carbohydrates into the vertebrate and Drosophila brain and how this transport is regulated. Blood-brain and hemolymph-brain transport functions are conserved and we can thus use a simple, genetically accessible model system to learn more about features and dynamics of metabolite transport into the brain.
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Affiliation(s)
- Astrid Weiler
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Anne Volkenhoff
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Helen Hertenstein
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany.
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Smith A, McFarland C, Hertenstein H, Kellum C, Allina T, Gulley D, Hansen J. Hemizygosity detected at 13 of 14 VNTR/STR loci in CD45/19+ Leukemia cells from a patient with ALL. Hum Immunol 2002. [DOI: 10.1016/s0198-8859(02)00520-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Kolb HJ, Mittermüller J, Hertenstein H, Schumm M, Holler E, de Witte T, Günther W, Ljungman P, Goldman JM. Adoptive immunotherapy in human and canine chimeras--the role of interferon alfa. EBMT Chronic Leukemia Working Party. Semin Hematol 1993; 30:37-9. [PMID: 8235705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- H J Kolb
- Medizinische Klinik III, Klinikum Grosshadern, Universität München, Germany
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