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Glück C, Zhou Q, Droux J, Chen Z, Glandorf L, Wegener S, Razansky D, Weber B, El Amki M. Pia-FLOW: Deciphering hemodynamic maps of the pial vascular connectome and its response to arterial occlusion. Proc Natl Acad Sci U S A 2024; 121:e2402624121. [PMID: 38954543 PMCID: PMC11252916 DOI: 10.1073/pnas.2402624121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 06/04/2024] [Indexed: 07/04/2024] Open
Abstract
The pial vasculature is the sole source of blood supply to the neocortex. The brain is contained within the skull, a vascularized bone marrow with a unique anatomical connection to the brain meninges. Recent developments in tissue clearing have enabled detailed mapping of the entire pial and calvarial vasculature. However, what are the absolute flow rate values of those vascular networks? This information cannot accurately be retrieved with the commonly used bioimaging methods. Here, we introduce Pia-FLOW, a unique approach based on large-scale transcranial fluorescence localization microscopy, to attain hemodynamic imaging of the whole murine pial and calvarial vasculature at frame rates up to 1,000 Hz and spatial resolution reaching 5.4 µm. Using Pia-FLOW, we provide detailed maps of flow velocity, direction, and vascular diameters which can serve as ground-truth data for further studies, advancing our understanding of brain fluid dynamics. Furthermore, Pia-FLOW revealed that the pial vascular network functions as one unit for robust allocation of blood after stroke.
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Affiliation(s)
- Chaim Glück
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich8057, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich8057, Switzerland
| | - Quanyu Zhou
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich8092, Switzerland
| | - Jeanne Droux
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich8057, Switzerland
- Department of Neurology, University Hospital and University of Zurich, Zurich8091, Switzerland
| | - Zhenyue Chen
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich8092, Switzerland
| | - Lukas Glandorf
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich8092, Switzerland
| | - Susanne Wegener
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich8057, Switzerland
- Department of Neurology, University Hospital and University of Zurich, Zurich8091, Switzerland
| | - Daniel Razansky
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich8057, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich8057, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich8092, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich8057, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich8057, Switzerland
| | - Mohamad El Amki
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich8057, Switzerland
- Department of Neurology, University Hospital and University of Zurich, Zurich8091, Switzerland
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2
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Faivre A, Bugarski M, Rinaldi A, Sakhi IB, Verissimo T, Legouis D, Rutkowski JM, Correia S, Kaminska M, Dalga D, Malpetti D, Cippa PE, de Seigneux S, Hall AM. Spatiotemporal Landscape of Kidney Tubular Responses to Glomerular Proteinuria. J Am Soc Nephrol 2024; 35:854-869. [PMID: 38652545 PMCID: PMC11230716 DOI: 10.1681/asn.0000000000000357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
Key Points Glomerular proteinuria induces large-scale changes in gene expression along the nephron. Increased protein uptake in the proximal tubule results in axial remodeling and injury. Increased protein delivery to the distal tubule causes dedifferentiation of the epithelium. Background Large increases in glomerular protein filtration induce major changes in body homeostasis and are associated with a higher risk of kidney functional decline and cardiovascular disease. We investigated how elevated protein exposure modifies the landscape of tubular function along the entire nephron, to understand the cellular changes that mediate these important clinical phenomena. Methods We conducted single-nucleus RNA sequencing, functional intravital imaging, and antibody staining to spatially map transport processes along the mouse kidney tubule. We then delineated how these were altered in a transgenic mouse model of inducible glomerular proteinuria (POD-ATTAC) at 7 and 28 days. Results Glomerular proteinuria activated large-scale and pleiotropic changes in gene expression in all major nephron sections. Extension of protein uptake from early (S1) to later (S2) parts of the proximal tubule initially triggered dramatic expansion of a hybrid S1/2 population, followed by injury and failed repair, with the cumulative effect of loss of canonical S2 functions. Proteinuria also induced acute injury in S3. Meanwhile, overflow of luminal proteins to the distal tubule caused transcriptional convergence between specialized regions and generalized dedifferentiation. Conclusions Proteinuria modulated cell signaling in tubular epithelia and caused distinct patterns of remodeling and injury in a segment-specific manner. Podcast This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2024_05_01_ASN0000000000000357.mp3
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Affiliation(s)
- Anna Faivre
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Anna Rinaldi
- Laboratories for Translational Research, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
- Division of Nephrology, Department of Medicine, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Imene B. Sakhi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Thomas Verissimo
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - David Legouis
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Division of Intensive Care, Department of Acute Medicine, University Hospital of Geneva, Geneva, Switzerland
| | | | - Sara Correia
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Monika Kaminska
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Delal Dalga
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Daniele Malpetti
- Istituto Dalle Molle di Studi sull'Intelligenza Artificiale (IDSIA), USI/SUPSI, Lugano, Switzerland
| | - Pietro E. Cippa
- Laboratories for Translational Research, Ente Ospedaliero Cantonale, Bellinzona, Switzerland
- Division of Nephrology, Department of Medicine, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Sophie de Seigneux
- Department of Medicine and Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Department of Medicine, Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
| | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
- Zurich Kidney Center, Zurich, Switzerland
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3
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Herwerth M, Wyss MT, Schmid NB, Condrau J, Ravotto L, Mateos Melero JM, Kaech A, Bredell G, Thomas C, Stadelmann C, Misgeld T, Bennett JL, Saab AS, Jessberger S, Weber B. Astrocytes adopt a progenitor-like migratory strategy for regeneration in adult brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.18.594292. [PMID: 38798654 PMCID: PMC11118580 DOI: 10.1101/2024.05.18.594292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Mature astrocytes become activated upon non-specific tissue damage and contribute to glial scar formation. Proliferation and migration of adult reactive astrocytes after injury is considered very limited. However, the regenerative behavior of individual astrocytes following selective astroglial loss, as seen in astrocytopathies, such as neuromyelitis optica spectrum disorder, remains unexplored. Here, we performed longitudinal in vivo imaging of cortical astrocytes after focal astrocyte ablation in mice. We discovered that perilesional astrocytes develop a remarkable plasticity for efficient lesion repopulation. A subset of mature astrocytes transforms into reactive progenitor-like (REPL) astrocytes that not only undergo multiple asymmetric divisions but also remain in a multinucleated interstage. This regenerative response facilitates efficient migration of newly formed daughter cell nuclei towards unoccupied astrocyte territories. Our findings define the cellular principles of astrocyte plasticity upon focal lesion, unravelling the REPL phenotype as a fundamental regenerative strategy of mature astrocytes to restore astrocytic networks in the adult mammalian brain. Promoting this regenerative phenotype bears therapeutic potential for neurological conditions involving glial dysfunction.
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Binder NF, El Amki M, Glück C, Middleham W, Reuss AM, Bertolo A, Thurner P, Deffieux T, Lambride C, Epp R, Handelsmann HL, Baumgartner P, Orset C, Bethge P, Kulcsar Z, Aguzzi A, Tanter M, Schmid F, Vivien D, Wyss MT, Luft A, Weller M, Weber B, Wegener S. Leptomeningeal collaterals regulate reperfusion in ischemic stroke and rescue the brain from futile recanalization. Neuron 2024; 112:1456-1472.e6. [PMID: 38412858 DOI: 10.1016/j.neuron.2024.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 11/18/2023] [Accepted: 01/30/2024] [Indexed: 02/29/2024]
Abstract
Recanalization is the mainstay of ischemic stroke treatment. However, even with timely clot removal, many stroke patients recover poorly. Leptomeningeal collaterals (LMCs) are pial anastomotic vessels with yet-unknown functions. We applied laser speckle imaging, ultrafast ultrasound, and two-photon microscopy in a thrombin-based mouse model of stroke and fibrinolytic treatment to show that LMCs maintain cerebral autoregulation and allow for gradual reperfusion, resulting in small infarcts. In mice with poor LMCs, distal arterial segments collapse, and deleterious hyperemia causes hemorrhage and mortality after recanalization. In silico analyses confirm the relevance of LMCs for preserving perfusion in the ischemic region. Accordingly, in stroke patients with poor collaterals undergoing thrombectomy, rapid reperfusion resulted in hemorrhagic transformation and unfavorable recovery. Thus, we identify LMCs as key components regulating reperfusion and preventing futile recanalization after stroke. Future therapeutic interventions should aim to enhance collateral function, allowing for beneficial reperfusion after stroke.
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Affiliation(s)
- Nadine Felizitas Binder
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Mohamad El Amki
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - William Middleham
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Anna Maria Reuss
- Institute of Neuropathology, University Hospital Zurich, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Adrien Bertolo
- Iconeus, 6 rue Jean Calvin, Paris, France; Physics for Medicine, INSERM U1273, ESPCI Paris, CNRS UMR 8063, PSL Research University, 17 rue Moreau, Paris, France
| | - Patrick Thurner
- Department of Neuroradiology, University Hospital and University of Zurich, Zürich, France
| | - Thomas Deffieux
- Physics for Medicine, INSERM U1273, ESPCI Paris, CNRS UMR 8063, PSL Research University, 17 rue Moreau, Paris, France
| | - Chryso Lambride
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Robert Epp
- Institute of Fluid Dynamics, ETH Zurich, Zurich, Switzerland
| | - Hannah-Lea Handelsmann
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland
| | - Philipp Baumgartner
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland
| | - Cyrille Orset
- Normandie University, UNICAEN, INSERM, Unité Mixte de Recherche-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Institute Blood and Brain @ Caen Normandie, GIP Cyceron, Caen, France
| | - Philipp Bethge
- Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Zsolt Kulcsar
- Department of Neuroradiology, University Hospital and University of Zurich, Zürich, France
| | - Adriano Aguzzi
- Institute of Neuropathology, University Hospital Zurich, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Mickael Tanter
- Physics for Medicine, INSERM U1273, ESPCI Paris, CNRS UMR 8063, PSL Research University, 17 rue Moreau, Paris, France
| | - Franca Schmid
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Denis Vivien
- Normandie University, UNICAEN, INSERM, Unité Mixte de Recherche-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Institute Blood and Brain @ Caen Normandie, GIP Cyceron, Caen, France; Department of Clinical Research, Caen Normandie University Hospital, Caen, France
| | - Matthias Tasso Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Andreas Luft
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Michael Weller
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
| | - Susanne Wegener
- Department of Neurology, University Hospital and University of Zurich, Zürich, Switzerland; Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland.
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5
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Zhou Q, Glück C, Tang L, Glandorf L, Droux J, El Amki M, Wegener S, Weber B, Razansky D, Chen Z. Cortex-wide transcranial localization microscopy with fluorescently labeled red blood cells. Nat Commun 2024; 15:3526. [PMID: 38664419 PMCID: PMC11045747 DOI: 10.1038/s41467-024-47892-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Large-scale imaging of brain activity with high spatio-temporal resolution is crucial for advancing our understanding of brain function. The existing neuroimaging techniques are largely limited by restricted field of view, slow imaging speed, or otherwise do not have the adequate spatial resolution to capture brain activities on a capillary and cellular level. To address these limitations, we introduce fluorescence localization microscopy aided with sparsely-labeled red blood cells for cortex-wide morphological and functional cerebral angiography with 4.9 µm spatial resolution and 1 s temporal resolution. When combined with fluorescence calcium imaging, the proposed method enables extended recordings of stimulus-evoked neuro-vascular changes in the murine brain while providing simultaneous multiparametric readings of intracellular neuronal activity, blood flow velocity/direction/volume, and vessel diameter. Owing to its simplicity and versatility, the proposed approach will become an invaluable tool for deciphering the regulation of cortical microcirculation and neurovascular coupling in health and disease.
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Affiliation(s)
- Quanyu Zhou
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Lin Tang
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Lukas Glandorf
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Jeanne Droux
- Zurich Neuroscience Center, Zurich, Switzerland
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Mohamad El Amki
- Zurich Neuroscience Center, Zurich, Switzerland
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Susanne Wegener
- Zurich Neuroscience Center, Zurich, Switzerland
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Daniel Razansky
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
- Zurich Neuroscience Center, Zurich, Switzerland.
| | - Zhenyue Chen
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
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6
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Looser ZJ, Faik Z, Ravotto L, Zanker HS, Jung RB, Werner HB, Ruhwedel T, Möbius W, Bergles DE, Barros LF, Nave KA, Weber B, Saab AS. Oligodendrocyte-axon metabolic coupling is mediated by extracellular K + and maintains axonal health. Nat Neurosci 2024; 27:433-448. [PMID: 38267524 PMCID: PMC10917689 DOI: 10.1038/s41593-023-01558-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/13/2023] [Indexed: 01/26/2024]
Abstract
The integrity of myelinated axons relies on homeostatic support from oligodendrocytes (OLs). To determine how OLs detect axonal spiking and how rapid axon-OL metabolic coupling is regulated in the white matter, we studied activity-dependent calcium (Ca2+) and metabolite fluxes in the mouse optic nerve. We show that fast axonal spiking triggers Ca2+ signaling and glycolysis in OLs. OLs detect axonal activity through increases in extracellular potassium (K+) concentrations and activation of Kir4.1 channels, thereby regulating metabolite supply to axons. Both pharmacological inhibition and OL-specific inactivation of Kir4.1 reduce the activity-induced axonal lactate surge. Mice lacking oligodendroglial Kir4.1 exhibit lower resting lactate levels and altered glucose metabolism in axons. These early deficits in axonal energy metabolism are associated with late-onset axonopathy. Our findings reveal that OLs detect fast axonal spiking through K+ signaling, making acute metabolic coupling possible and adjusting the axon-OL metabolic unit to promote axonal health.
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Affiliation(s)
- Zoe J Looser
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Zainab Faik
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Henri S Zanker
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.
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7
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Lees RM, Bianco IH, Campbell RAA, Orlova N, Peterka DS, Pichler B, Smith SL, Yatsenko D, Yu CH, Packer AM. Standardised Measurements for Monitoring and Comparing Multiphoton Microscope Systems. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576417. [PMID: 38328224 PMCID: PMC10849699 DOI: 10.1101/2024.01.23.576417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The goal of this protocol is to enable better characterisation of multiphoton microscopy hardware across a large user base. The scope of this protocol is purposefully limited to focus on hardware, touching on software and data analysis routines only where relevant. The intended audiences are scientists using and building multiphoton microscopes in their laboratories. The goal is that any scientist, not only those with optical expertise, can test whether their multiphoton microscope is performing well and producing consistent data over the lifetime of their system.
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Affiliation(s)
- Robert M Lees
- Science and Technology Facilities Council, Octopus imaging facility, Research Complex at Harwell, Harwell Campus, Oxfordshire, UK
| | - Isaac H Bianco
- Department of Neuroscience, Physiology & Pharmacology, University College London, UK
| | | | | | - Darcy S Peterka
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Bruno Pichler
- Independent NeuroScience Services INSS Ltd, Lewes, East Sussex, UK
| | - Spencer LaVere Smith
- Department of Electrical and Computer Engineering, University of California Santa Barbara, USA
| | | | - Che-Hang Yu
- Department of Electrical and Computer Engineering, University of California Santa Barbara, USA
| | - Adam M Packer
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, UK
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8
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Barros LF, Ruminot I, Sandoval PY, San Martín A. Enlightening brain energy metabolism. Neurobiol Dis 2023:106211. [PMID: 37352985 DOI: 10.1016/j.nbd.2023.106211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/06/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023] Open
Abstract
Brain tissue metabolism is distributed across several cell types and subcellular compartments, which activate at different times and with different temporal patterns. The introduction of genetically-encoded fluorescent indicators that are imaged using time-lapse microscopy has opened the possibility of studying brain metabolism at cellular and sub-cellular levels. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides, which inform about relative levels, concentrations and fluxes. This review offers a brief survey of the metabolic indicators that have been validated in brain cells, with some illustrative examples from the literature. Whereas only a small fraction of the metabolome is currently accessible to fluorescent probes, there are grounds to be optimistic about coming developments and the application of these tools to the study of brain disease.
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Affiliation(s)
- L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile.
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Ciencias para el Cuidado de La Salud, Universidad San Sebastián, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Ciencias para el Cuidado de La Salud, Universidad San Sebastián, Valdivia, Chile
| | - A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Facultad de Ciencias para el Cuidado de La Salud, Universidad San Sebastián, Valdivia, Chile
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9
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Todorova V, Stauffacher MF, Ravotto L, Nötzli S, Karademir D, Ebner LJA, Imsand C, Merolla L, Hauck SM, Samardzija M, Saab AS, Barros LF, Weber B, Grimm C. Deficits in mitochondrial TCA cycle and OXPHOS precede rod photoreceptor degeneration during chronic HIF activation. Mol Neurodegener 2023; 18:15. [PMID: 36882871 PMCID: PMC9990367 DOI: 10.1186/s13024-023-00602-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 02/03/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Major retinal degenerative diseases, including age-related macular degeneration, diabetic retinopathy and retinal detachment, are associated with a local decrease in oxygen availability causing the formation of hypoxic areas affecting the photoreceptor (PR) cells. Here, we addressed the underlying pathological mechanisms of PR degeneration by focusing on energy metabolism during chronic activation of hypoxia-inducible factors (HIFs) in rod PR. METHODS We used two-photon laser scanning microscopy (TPLSM) of genetically encoded biosensors delivered by adeno-associated viruses (AAV) to determine lactate and glucose dynamics in PR and inner retinal cells. Retinal layer-specific proteomics, in situ enzymatic assays and immunofluorescence studies were used to analyse mitochondrial metabolism in rod PRs during chronic HIF activation. RESULTS PRs exhibited remarkably higher glycolytic flux through the hexokinases than neurons of the inner retina. Chronic HIF activation in rods did not cause overt change in glucose dynamics but an increase in lactate production nonetheless. Furthermore, dysregulation of the oxidative phosphorylation pathway (OXPHOS) and tricarboxylic acid (TCA) cycle in rods with an activated hypoxic response decelerated cellular anabolism causing shortening of rod photoreceptor outer segments (OS) before onset of cell degeneration. Interestingly, rods with deficient OXPHOS but an intact TCA cycle did not exhibit these early signs of anabolic dysregulation and showed a slower course of degeneration. CONCLUSION Together, these data indicate an exceeding high glycolytic flux in rods and highlight the importance of mitochondrial metabolism and especially of the TCA cycle for PR survival in conditions of increased HIF activity.
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Affiliation(s)
- Vyara Todorova
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Mia Fee Stauffacher
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology and Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - Sarah Nötzli
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Duygu Karademir
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Lynn J A Ebner
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Cornelia Imsand
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Luca Merolla
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764, Munich, Germany
| | - Marijana Samardzija
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology and Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile.,Universidad San Sebastián, Valdivia, Chile
| | - Bruno Weber
- Institute of Pharmacology and Toxicology and Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Wagistrasse 14, 8952, Schlieren, Switzerland.
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10
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Eleftheriou A, Ravotto L, Wyss MT, Warnock G, Siebert A, Zaiss M, Weber B. Simultaneous dynamic glucose-enhanced (DGE) MRI and fiber photometry measurements of glucose in the healthy mouse brain. Neuroimage 2023; 265:119762. [PMID: 36427752 DOI: 10.1016/j.neuroimage.2022.119762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/27/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
Glucose is the main energy source in the brain and its regulated uptake and utilization are important biomarkers of pathological brain function. Glucose Chemical Exchange Saturation Transfer (GlucoCEST) and its time-resolved version Dynamic Glucose-Enhanced MRI (DGE) are promising approaches to monitor glucose and detect tumors, since they are radioactivity-free, do not require 13C labeling and are is easily translatable to the clinics. The main principle of DGE is clear. However, what remains to be established is to which extent the signal reflects vascular, extracellular or intracellular glucose. To elucidate the compartmental contributions to the DGE signal, we coupled it with FRET-based fiber photometry of genetically encoded sensors, a technique that combines quantitative glucose readout with cellular specificity. The glucose sensor FLIIP was used with fiber photometry to measure astrocytic and neuronal glucose changes upon injection of D-glucose, 3OMG and L-glucose, in the anaesthetized murine brain. By correlating the kinetic profiles of the techniques, we demonstrate the presence of a vascular contribution to the signal, especially at early time points after injection. Furthermore, we show that, in the case of the commonly used contrast agent 3OMG, the DGE signal actually anticorrelates with the glucose concentration in neurons and astrocytes.
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Affiliation(s)
- Afroditi Eleftheriou
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Luca Ravotto
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland
| | - Matthias T Wyss
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Geoffrey Warnock
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland
| | - Anita Siebert
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland
| | - Moritz Zaiss
- Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander University Erlangen Nürnberg, Erlangen, Germany; High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Bruno Weber
- University of Zurich, Institute of Pharmacology and Toxicology, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.
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11
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Zhou Q, Chen Z, Liu YH, El Amki M, Glück C, Droux J, Reiss M, Weber B, Wegener S, Razansky D. Three-dimensional wide-field fluorescence microscopy for transcranial mapping of cortical microcirculation. Nat Commun 2022; 13:7969. [PMID: 36577750 PMCID: PMC9797555 DOI: 10.1038/s41467-022-35733-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/16/2022] [Indexed: 12/29/2022] Open
Abstract
Wide-field fluorescence imaging is an indispensable tool for studying large-scale biodynamics. Limited space-bandwidth product and strong light diffusion make conventional implementations incapable of high-resolution mapping of fluorescence biodistribution in three dimensions. We introduce a volumetric wide-field fluorescence microscopy based on optical astigmatism combined with fluorescence source localization, covering 5.6×5.6×0.6 mm3 imaging volume. Two alternative configurations are proposed exploiting multifocal illumination or sparse localization of point emitters, which are herein seamlessly integrated in one system. We demonstrate real-time volumetric mapping of the murine cortical microcirculation at capillary resolution without employing cranial windows, thus simultaneously delivering quantitative perfusion information across both brain hemispheres. Morphological and functional changes of cerebral vascular networks are further investigated after an acute ischemic stroke, enabling cortex-wide observation of concurrent collateral recruitment events occurring on a sub-second scale. The reported technique thus offers a wealth of unmatched possibilities for non- or minimally invasive imaging of biodynamics across scales.
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Affiliation(s)
- Quanyu Zhou
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Zhenyue Chen
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Yu-Hang Liu
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Mohamad El Amki
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Jeanne Droux
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Michael Reiss
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Susanne Wegener
- Department of Neurology, University Hospital and University of Zurich, Zurich, Switzerland
- Zurich Neuroscience Center, Zurich, Switzerland
| | - Daniel Razansky
- Institute of Pharmacology and Toxicology, Faculty of Medicine, University of Zurich, Zurich, Switzerland.
- Institute for Biomedical Engineering, Department of Information Technology and Electrical Engineering, ETH Zurich, Zurich, Switzerland.
- Zurich Neuroscience Center, Zurich, Switzerland.
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12
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Stobart JL, Erlebach E, Glück C, Huang SF, Barrett MJ, Li M, Vinogradov SA, Klohs J, Zarb Y, Keller A, Weber B. Altered hemodynamics and vascular reactivity in a mouse model with severe pericyte deficiency. J Cereb Blood Flow Metab 2022; 43:763-777. [PMID: 36545806 PMCID: PMC10108184 DOI: 10.1177/0271678x221147366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pericytes are the mural cells of the microvascular network that are in close contact with underlying endothelial cells. Endothelial-secreted PDGFB leads to recruitment of pericytes to the vessel wall, but this is disrupted in Pdgfbret/ret mice when the PDGFB retention motif is deleted. This results in severely reduced pericyte coverage on blood vessels. In this study, we investigated vascular abnormalities and hemodynamics in Pdgfbret/ret mice throughout the cerebrovascular network and in different cortical layers by in vivo two-photon microscopy. We confirmed that Pdgfbret/ret mice are severely deficient in pericytes throughout the vascular network, with enlarged brain blood vessels and a reduced number of vessel branches. Red blood cell velocity, linear density, and tube hematocrit were reduced in Pdgfbret/ret mice, which may impair oxygen delivery to the tissue. We also measured intravascular PO2 and found that concentrations were higher in cortical Layer 2/3 in Pdgfbret/ret mice, indicative of reduced blood oxygen extraction. Finally, we found that Pdgfbret/ret mice had a reduced capacity for vasodilation in response to an acetazolamide challenge during functional MRI imaging. Taken together, these results suggest that severe pericyte deficiency can lead to vascular abnormalities and altered cerebral blood flow, reminiscent of pathologies such as arteriovenous malformations.
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Affiliation(s)
- Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center, University and ETH Zurich, Zurich, Switzerland.,College of Pharmacy, University of Manitoba, Winnipeg, MB, Canada
| | - Eva Erlebach
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center, University and ETH Zurich, Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center, University and ETH Zurich, Zurich, Switzerland
| | - Sheng-Fu Huang
- Neuroscience Center, University and ETH Zurich, Zurich, Switzerland.,Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zürich, Switzerland
| | - Matthew Jp Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center, University and ETH Zurich, Zurich, Switzerland
| | - Max Li
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center, University and ETH Zurich, Zurich, Switzerland
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jan Klohs
- Neuroscience Center, University and ETH Zurich, Zurich, Switzerland.,Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Yvette Zarb
- Neuroscience Center, University and ETH Zurich, Zurich, Switzerland.,Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zürich, Switzerland
| | - Annika Keller
- Neuroscience Center, University and ETH Zurich, Zurich, Switzerland.,Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zürich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Neuroscience Center, University and ETH Zurich, Zurich, Switzerland
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13
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Erlebach E, Ravotto L, Wyss MT, Condrau J, Troxler T, Vinogradov SA, Weber B. Measurement of cerebral oxygen pressure in living mice by two-photon phosphorescence lifetime microscopy. STAR Protoc 2022; 3:101370. [PMID: 35573482 PMCID: PMC9092998 DOI: 10.1016/j.xpro.2022.101370] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The ability to quantify partial pressure of oxygen (pO2) is of primary importance for studies of metabolic processes in health and disease. Here, we present a protocol for imaging of oxygen distributions in tissue and vasculature of the cerebral cortex of anesthetized and awake mice. We describe in vivo two-photon phosphorescence lifetime microscopy (2PLM) of oxygen using the probe Oxyphor 2P. This minimally invasive protocol outperforms existing approaches in terms of accuracy, resolution, and imaging depth. For complete details on the use and execution of this protocol, please refer to Esipova et al. (2019). Two-photon phosphorescence imaging of Oxyphor 2P allows for oxygen measurement in vivo Oxygen imaging can be performed in anesthetized or awake, behaving mice Intravenous injection enables oxygen imaging in the vasculature Cisterna magna injection enables extra- and intravascular oxygen imaging in the brain
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Affiliation(s)
- Eva Erlebach
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
| | - Matthias T. Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
| | - Jacqueline Condrau
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
| | - Thomas Troxler
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sergei A. Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
- Corresponding author
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zürich, Switzerland
- Corresponding author
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14
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Hösli L, Zuend M, Bredell G, Zanker HS, Porto de Oliveira CE, Saab AS, Weber B. Direct vascular contact is a hallmark of cerebral astrocytes. Cell Rep 2022; 39:110599. [PMID: 35385728 DOI: 10.1016/j.celrep.2022.110599] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/09/2022] [Accepted: 03/09/2022] [Indexed: 12/15/2022] Open
Abstract
Astrocytes establish extensive networks via gap junctions that allow each astrocyte to connect indirectly to the vasculature. However, the proportion of astrocytes directly associated with blood vessels is unknown. Here, we quantify structural contacts of cortical astrocytes with the vasculature in vivo. We show that all cortical astrocytes are connected to at least one blood vessel. Moreover, astrocytes contact more vessels in deeper cortical layers where vessel density is known to be higher. Further examination of different brain regions reveals that only the hippocampus, which has the lowest vessel density of all investigated brain regions, harbors single astrocytes with no apparent vascular connection. In summary, we show that almost all gray matter astrocytes have direct contact to the vasculature. In addition to the glial network, a direct vascular access may represent a complementary pathway for metabolite uptake and distribution.
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Affiliation(s)
- Ladina Hösli
- University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Marc Zuend
- University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Gustav Bredell
- ETH Zurich, Computer Vision Laboratory, Department of Information Technology and Electrical Engineering, 8092 Zurich, Switzerland
| | - Henri S Zanker
- University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Carlos Eduardo Porto de Oliveira
- ETH Zurich, Computer Vision Laboratory, Department of Information Technology and Electrical Engineering, 8092 Zurich, Switzerland
| | - Aiman S Saab
- University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Bruno Weber
- University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.
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15
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Hösli L, Binini N, Ferrari KD, Thieren L, Looser ZJ, Zuend M, Zanker HS, Berry S, Holub M, Möbius W, Ruhwedel T, Nave KA, Giaume C, Weber B, Saab AS. Decoupling astrocytes in adult mice impairs synaptic plasticity and spatial learning. Cell Rep 2022; 38:110484. [PMID: 35263595 DOI: 10.1016/j.celrep.2022.110484] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/20/2021] [Accepted: 02/14/2022] [Indexed: 12/16/2022] Open
Abstract
The mechanisms by which astrocytes modulate neural homeostasis, synaptic plasticity, and memory are still poorly explored. Astrocytes form large intercellular networks by gap junction coupling, mainly composed of two gap junction channel proteins, connexin 30 (Cx30) and connexin 43 (Cx43). To circumvent developmental perturbations and to test whether astrocytic gap junction coupling is required for hippocampal neural circuit function and behavior, we generate and study inducible, astrocyte-specific Cx30 and Cx43 double knockouts. Surprisingly, disrupting astrocytic coupling in adult mice results in broad activation of astrocytes and microglia, without obvious signs of pathology. We show that hippocampal CA1 neuron excitability, excitatory synaptic transmission, and long-term potentiation are significantly affected. Moreover, behavioral inspection reveals deficits in sensorimotor performance and a complete lack of spatial learning and memory. Together, our findings establish that astrocytic connexins and an intact astroglial network in the adult brain are vital for neural homeostasis, plasticity, and spatial cognition.
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Affiliation(s)
- Ladina Hösli
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Noemi Binini
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Laetitia Thieren
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Zoe J Looser
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Henri S Zanker
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Stewart Berry
- Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Martin Holub
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Wiebke Möbius
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Torben Ruhwedel
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Klaus-Armin Nave
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, 75231 Paris Cedex 05, France
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.
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16
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San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
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Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
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17
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Duffet L, Kosar S, Panniello M, Viberti B, Bracey E, Zych AD, Radoux-Mergault A, Zhou X, Dernic J, Ravotto L, Tsai YC, Figueiredo M, Tyagarajan SK, Weber B, Stoeber M, Gogolla N, Schmidt MH, Adamantidis AR, Fellin T, Burdakov D, Patriarchi T. A genetically encoded sensor for in vivo imaging of orexin neuropeptides. Nat Methods 2022; 19:231-241. [PMID: 35145320 PMCID: PMC8831244 DOI: 10.1038/s41592-021-01390-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 12/16/2021] [Indexed: 02/07/2023]
Abstract
Orexins (also called hypocretins) are hypothalamic neuropeptides that carry out essential functions in the central nervous system; however, little is known about their release and range of action in vivo owing to the limited resolution of current detection technologies. Here we developed a genetically encoded orexin sensor (OxLight1) based on the engineering of circularly permutated green fluorescent protein into the human type-2 orexin receptor. In mice OxLight1 detects optogenetically evoked release of endogenous orexins in vivo with high sensitivity. Photometry recordings of OxLight1 in mice show rapid orexin release associated with spontaneous running behavior, acute stress and sleep-to-wake transitions in different brain areas. Moreover, two-photon imaging of OxLight1 reveals orexin release in layer 2/3 of the mouse somatosensory cortex during emergence from anesthesia. Thus, OxLight1 enables sensitive and direct optical detection of orexin neuropeptides with high spatiotemporal resolution in living animals.
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Affiliation(s)
- Loïc Duffet
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Seher Kosar
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Mariangela Panniello
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
| | - Bianca Viberti
- Center for Experimental Neurology (ZEN), Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Edward Bracey
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Anna D Zych
- Circuits for Emotion Research Group, Max Planck Institute of Neurobiology, Martinsried, Germany
- International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Munich, Germany
| | | | - Xuehan Zhou
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Jan Dernic
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Luca Ravotto
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Yuan-Chen Tsai
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Marta Figueiredo
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Shiva K Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
| | - Miriam Stoeber
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nadine Gogolla
- Circuits for Emotion Research Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Markus H Schmidt
- Center for Experimental Neurology (ZEN), Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Antoine R Adamantidis
- Center for Experimental Neurology (ZEN), Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Tommaso Fellin
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
| | - Denis Burdakov
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.
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18
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Bapst AM, Knöpfel T, Nolan KA, Imeri F, Schuh CD, Hall AM, Guo J, Katschinski DM, Wenger RH. Neurogenic and pericytic plasticity of conditionally immortalized cells derived from renal erythropoietin-producing cells. J Cell Physiol 2022; 237:2420-2433. [PMID: 35014036 PMCID: PMC9303970 DOI: 10.1002/jcp.30677] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 12/19/2022]
Abstract
In adult mammals, the kidney is the main source of circulating erythropoietin (Epo), the master regulator of erythropoiesis. In vivo data in mice demonstrated multiple subtypes of interstitial renal Epo‐producing (REP) cells. To analyze the differentiation plasticity of fibroblastoid REP cells, we used a transgenic REP cell reporter mouse model to generate conditionally immortalized REP‐derived (REPD) cell lines. Under nonpermissive conditions, REPD cells ceased from proliferation and acquired a stem cell‐like state, with strongly enhanced hypoxia‐inducible factor 2 (HIF‐2α), stem cell antigen 1 (SCA‐1), and CD133 expression, but also enhanced alpha‐smooth muscle actin (αSMA) expression, indicating myofibroblastic signaling. These cells maintained the “on‐off” nature of Epo expression observed in REP cells in vivo, whereas other HIF target genes showed a more permanent regulation. Like REP cells in vivo, REPD cells cultured in vitro generated long tunneling nanotubes (TNTs) that aligned with endothelial vascular structures, were densely packed with mitochondria and became more numerous under hypoxic conditions. Although inhibition of mitochondrial oxygen consumption blunted HIF signaling, removal of the TNTs did not affect or even enhance the expression of HIF target genes. Apart from pericytes, REPD cells readily differentiated into neuroglia but not adipogenic, chondrogenic, or osteogenic lineages, consistent with a neuronal origin of at least a subpopulation of REP cells. In summary, these results suggest an unprecedented combination of differentiation features of this unique cell type.
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Affiliation(s)
- Andreas M Bapst
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Karen A Nolan
- Institute of Physiology, University of Zürich, Zürich, Switzerland.,National Centre of Competence in Research "Kidney.CH", University of Zürich, Zürich, Switzerland
| | - Faik Imeri
- Institute of Physiology, University of Zürich, Zürich, Switzerland.,National Centre of Competence in Research "Kidney.CH", University of Zürich, Zürich, Switzerland
| | - Claus D Schuh
- National Centre of Competence in Research "Kidney.CH", University of Zürich, Zürich, Switzerland.,Institute of Anatomy, University of Zürich, Zürich, Switzerland
| | - Andrew M Hall
- National Centre of Competence in Research "Kidney.CH", University of Zürich, Zürich, Switzerland.,Institute of Anatomy, University of Zürich, Zürich, Switzerland
| | - Jia Guo
- Institute for Cardiovascular Physiology, University Medical Center Göttingen, Georg-August-University, Göttingen, Germany
| | - Dörthe M Katschinski
- Institute for Cardiovascular Physiology, University Medical Center Göttingen, Georg-August-University, Göttingen, Germany
| | - Roland H Wenger
- Institute of Physiology, University of Zürich, Zürich, Switzerland.,National Centre of Competence in Research "Kidney.CH", University of Zürich, Zürich, Switzerland
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19
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El Amki M, Glück C, Binder N, Middleham W, Wyss MT, Weiss T, Meister H, Luft A, Weller M, Weber B, Wegener S. Neutrophils Obstructing Brain Capillaries Are a Major Cause of No-Reflow in Ischemic Stroke. Cell Rep 2021; 33:108260. [PMID: 33053341 DOI: 10.1016/j.celrep.2020.108260] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 08/18/2020] [Accepted: 09/21/2020] [Indexed: 12/29/2022] Open
Abstract
Despite successful clot retrieval in large vessel occlusion stroke, ∼50% of patients have an unfavorable clinical outcome. The mechanisms underlying this functional reperfusion failure remain unknown, and therapeutic options are lacking. In the thrombin-model of middle cerebral artery (MCA) stroke in mice, we show that, despite successful thrombolytic recanalization of the proximal MCA, cortical blood flow does not fully recover. Using in vivo two-photon imaging, we demonstrate that this is due to microvascular obstruction of ∼20%-30% of capillaries in the infarct core and penumbra by neutrophils adhering to distal capillary segments. Depletion of circulating neutrophils using an anti-Ly6G antibody restores microvascular perfusion without increasing the rate of hemorrhagic complications. Strikingly, infarct size and functional deficits are smaller in mice treated with anti-Ly6G. Thus, we propose neutrophil stalling of brain capillaries to contribute to reperfusion failure, which offers promising therapeutic avenues for ischemic stroke.
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Affiliation(s)
- Mohamad El Amki
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Chaim Glück
- Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Nadine Binder
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - William Middleham
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Matthias T Wyss
- Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Tobias Weiss
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Hanna Meister
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Andreas Luft
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Michael Weller
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland
| | - Bruno Weber
- Experimental Imaging and Neuroenergetics, Institute of Pharmacology and Toxicology, University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland.
| | - Susanne Wegener
- Department of Neurology, University Hospital and University of Zurich, and Zurich Neuroscience Center, Zurich, Switzerland.
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20
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Glück C, Ferrari KD, Binini N, Keller A, Saab AS, Stobart JL, Weber B. Distinct signatures of calcium activity in brain mural cells. eLife 2021; 10:e70591. [PMID: 34227466 PMCID: PMC8294852 DOI: 10.7554/elife.70591] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/15/2021] [Indexed: 12/15/2022] Open
Abstract
Pericytes have been implicated in various neuropathologies, yet little is known about their function and signaling pathways in health. Here, we characterized calcium dynamics of cortical mural cells in anesthetized or awake Pdgfrb-CreERT2;Rosa26< LSL-GCaMP6s > mice and in acute brain slices. Smooth muscle cells (SMCs) and ensheathing pericytes (EPs), also named as terminal vascular SMCs, revealed similar calcium dynamics in vivo. In contrast, calcium signals in capillary pericytes (CPs) were irregular, higher in frequency, and occurred in cellular microdomains. In the absence of the vessel constricting agent U46619 in acute slices, SMCs and EPs revealed only sparse calcium signals, whereas CPs retained their spontaneous calcium activity. Interestingly, chemogenetic activation of neurons in vivo and acute elevations of extracellular potassium in brain slices strongly decreased calcium activity in CPs. We propose that neuronal activation and an extracellular increase in potassium suppress calcium activity in CPs, likely mediated by Kir2.2 and KATP channels.
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Affiliation(s)
- Chaim Glück
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Noemi Binini
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Annika Keller
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
- Department of Neurosurgery, University of ZurichSchlierenSwitzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
| | - Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Rady Faculty of Health Sciences, College of PharmacyWinnipegCanada
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of ZurichZürichSwitzerland
- Neuroscience Center Zurich, University and ETH ZurichZurichSwitzerland
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21
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Barz CS, Garderes PM, Ganea DA, Reischauer S, Feldmeyer D, Haiss F. Functional and Structural Properties of Highly Responsive Somatosensory Neurons in Mouse Barrel Cortex. Cereb Cortex 2021; 31:4533-4553. [PMID: 33963394 PMCID: PMC8408454 DOI: 10.1093/cercor/bhab104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 03/12/2021] [Accepted: 03/24/2021] [Indexed: 11/14/2022] Open
Abstract
Sparse population activity is a well-known feature of supragranular sensory neurons in neocortex. The mechanisms underlying sparseness are not well understood because a direct link between the neurons activated in vivo, and their cellular properties investigated in vitro has been missing. We used two-photon calcium imaging to identify a subset of neurons in layer L2/3 (L2/3) of mouse primary somatosensory cortex that are highly active following principal whisker vibrotactile stimulation. These high responders (HRs) were then tagged using photoconvertible green fluorescent protein for subsequent targeting in the brain slice using intracellular patch-clamp recordings and biocytin staining. This approach allowed us to investigate the structural and functional properties of HRs that distinguish them from less active control cells. Compared to less responsive L2/3 neurons, HRs displayed increased levels of stimulus-evoked and spontaneous activity, elevated noise and spontaneous pairwise correlations, and stronger coupling to the population response. Intrinsic excitability was reduced in HRs, while we found no evidence for differences in other electrophysiological and morphological parameters. Thus, the choice of which neurons participate in stimulus encoding may be determined largely by network connectivity rather than by cellular structure and function.
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Affiliation(s)
- C S Barz
- Institute of Neuroscience and Medicine, INM-10, Research Centre Jülich, 52425 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Jülich-Aachen Research Alliance - Translational Brain Medicine, 52074 Aachen, Germany.,IZKF Aachen, Medical School, RWTH Aachen University, 52074 Aachen, Germany
| | - P M Garderes
- IZKF Aachen, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Department of Neuropathology, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Department of Ophthalmology, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Unit of Neural Circuits Dynamics and Decision Making, Institut Pasteur, 75015 Paris, France
| | - D A Ganea
- IZKF Aachen, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Department of Neuropathology, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Department of Ophthalmology, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Biomedical Department, University of Basel, 4056 Basel, Switzerland
| | - S Reischauer
- Medical Clinic I, (Cardiology/Angiology) and Campus Kerckhoff, Justus-Liebig-University Giessen, 35390 Giessen Germany.,Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.,Cardio-Pulmonary Institute (CPI), 35392 Giessen, Germany
| | - D Feldmeyer
- Institute of Neuroscience and Medicine, INM-10, Research Centre Jülich, 52425 Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Jülich-Aachen Research Alliance - Translational Brain Medicine, 52074 Aachen, Germany
| | - F Haiss
- IZKF Aachen, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Department of Neuropathology, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Department of Ophthalmology, Medical School, RWTH Aachen University, 52074 Aachen, Germany.,Unit of Neural Circuits Dynamics and Decision Making, Institut Pasteur, 75015 Paris, France
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22
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Bugarski M, Ghazi S, Polesel M, Martins JR, Hall AM. Changes in NAD and Lipid Metabolism Drive Acidosis-Induced Acute Kidney Injury. J Am Soc Nephrol 2021; 32:342-356. [PMID: 33478973 PMCID: PMC8054907 DOI: 10.1681/asn.2020071003] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 10/30/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The kidney plays an important role in maintaining normal blood pH. Metabolic acidosis (MA) upregulates the pathway that mitochondria in the proximal tubule (PT) use to produce ammonia and bicarbonate from glutamine, and is associated with AKI. However, the extent to which MA causes AKI, and thus whether treating MA would be beneficial, is unclear. METHODS Gavage with ammonium chloride induced acute MA. Multiphoton imaging of mitochondria (NADH/membrane potential) and transport function (dextran/albumin uptake), oxygen consumption rate (OCR) measurements in isolated tubules, histologic analysis, and electron microscopy in fixed tissue, and urinary biomarkers (KIM-1/clara cell 16) assessed tubular cell structure and function in mouse kidney cortex. RESULTS MA induces an acute change in NAD redox state (toward oxidation) in PT mitochondria, without changing the mitochondrial energization state. This change is associated with a switch toward complex I activity and decreased maximal OCR, and a major alteration in normal lipid metabolism, resulting in marked lipid accumulation in PTs and the formation of large multilamellar bodies. These changes, in turn, lead to acute tubular damage and a severe defect in solute uptake. Increasing blood pH with intravenous bicarbonate substantially improves tubular function, whereas preinjection with the NAD precursor nicotinamide (NAM) is highly protective. CONCLUSIONS MA induces AKI via changes in PT NAD and lipid metabolism, which can be reversed or prevented by treatment strategies that are viable in humans. These findings might also help to explain why MA accelerates decline in function in CKD.
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Affiliation(s)
- Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Susan Ghazi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | - Joana R. Martins
- Institute of Anatomy, University of Zurich, Zurich, Switzerland,Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland,Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
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23
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Martins JR, Haenni D, Bugarski M, Figurek A, Hall AM. Quantitative intravital Ca2+ imaging maps single cell behavior to kidney tubular structure. Am J Physiol Renal Physiol 2020; 319:F245-F255. [DOI: 10.1152/ajprenal.00052.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ca2+ is an important second messenger that translates extracellular stimuli into intracellular responses. Although there has been significant progress in understanding Ca2+ dynamics in organs such as the brain, the nature of Ca2+ signals in the kidney is still poorly understood. Here, we show that by using a genetically expressed highly sensitive reporter (GCaMP6s), it is possible to perform imaging of Ca2+ signals at high resolution in the mouse kidney in vivo. Moreover, by applying machine learning-based automated analysis using a Ca2+-independent signal, quantitative data can be extracted in an unbiased manner. By projecting the resulting data onto the structure of the kidney, we show that different tubular segments display highly distinct spatiotemporal patterns of Ca2+ signals. Furthermore, we provide evidence that Ca2+ activity in the proximal tubule decreases with increasing distance from the glomerulus. Finally, we demonstrate that substantial changes in intracellular Ca2+ can be detected in proximal tubules in a cisplatin model of acute kidney injury, which can be linked to alterations in cell structure and transport function. In summary, we describe a powerful new tool to investigate how single cell behavior is integrated with whole organ structure and function and how it is altered in disease states relevant to humans.
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Affiliation(s)
| | - Dominik Haenni
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andreja Figurek
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
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24
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Aydin AK, Haselden WD, Goulam Houssen Y, Pouzat C, Rungta RL, Demené C, Tanter M, Drew PJ, Charpak S, Boido D. Transfer functions linking neural calcium to single voxel functional ultrasound signal. Nat Commun 2020; 11:2954. [PMID: 32528069 PMCID: PMC7290037 DOI: 10.1038/s41467-020-16774-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 05/11/2020] [Indexed: 12/13/2022] Open
Abstract
Functional ultrasound imaging (fUS) is an emerging technique that detects changes of cerebral blood volume triggered by brain activation. Here, we investigate the extent to which fUS faithfully reports local neuronal activation by combining fUS and two-photon microscopy (2PM) in a co-registered single voxel brain volume. Using a machine-learning approach, we compute and validate transfer functions between dendritic calcium signals of specific neurons and vascular signals measured at both microscopic (2PM) and mesoscopic (fUS) levels. We find that transfer functions are robust across a wide range of stimulation paradigms and animals, and reveal a second vascular component of neurovascular coupling upon very strong stimulation. We propose that transfer functions can be considered as reliable quantitative reporters to follow neurovascular coupling dynamics. Neurovascular coupling refers to changes in cerebral blood flow in response to neuronal stimulation, but to what extent this change can report neuronal activation is not known. Here the authors develop transfer functions between neural calcium signals and functional ultrasound changes in blood volume in co-registered single voxel brain volumes.
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Affiliation(s)
- Ali-Kemal Aydin
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université de Paris, Paris, France.,INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - William D Haselden
- Medical Scientist Training Program and Neuroscience Graduate Program, The Pennsylvania State University, University Park, PA, USA
| | - Yannick Goulam Houssen
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université de Paris, Paris, France
| | - Christophe Pouzat
- MAP5, Mathématiques Appliquées Paris 5, CNRS UMR 8145, Paris, France
| | - Ravi L Rungta
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université de Paris, Paris, France.,INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Charlie Demené
- Physics for Medicine, ESPCI, INSERM, CNRS, PSL Research University, Paris, France
| | - Mickael Tanter
- Physics for Medicine, ESPCI, INSERM, CNRS, PSL Research University, Paris, France
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Serge Charpak
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université de Paris, Paris, France. .,INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France.
| | - Davide Boido
- INSERM U1128, Laboratory of Neurophysiology and New Microscopy, Université de Paris, Paris, France. .,NeuroSpin, Bât 145, Commissariat à l'Energie Atomique-Saclay Center, 91191, Gif-sur-Yvette, France.
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25
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Zuend M, Saab AS, Wyss MT, Ferrari KD, Hösli L, Looser ZJ, Stobart JL, Duran J, Guinovart JJ, Barros LF, Weber B. Arousal-induced cortical activity triggers lactate release from astrocytes. Nat Metab 2020; 2:179-191. [PMID: 32694692 DOI: 10.1038/s42255-020-0170-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 01/15/2020] [Indexed: 01/01/2023]
Abstract
It has been suggested that, in states of arousal, release of noradrenaline and β-adrenergic signalling affect long-term memory formation by stimulating astrocytic lactate production from glycogen. However, the temporal relationship between cortical activity and cellular lactate fluctuations upon changes in arousal remains to be fully established. Also, the role of β-adrenergic signalling and brain glycogen metabolism on neural lactate dynamics in vivo is still unknown. Here, we show that an arousal-induced increase in cortical activity triggers lactate release into the extracellular space, and this correlates with a fast and prominent lactate dip in astrocytes. The immediate drop in astrocytic lactate concentration and the parallel increase in extracellular lactate levels underline an activity-dependent lactate release from astrocytes. Moreover, when β-adrenergic signalling is blocked or the brain is depleted of glycogen, the arousal-evoked cellular lactate surges are significantly reduced. We provide in vivo evidence that cortical activation upon arousal triggers lactate release from astrocytes, a rise in intracellular lactate levels mediated by β-adrenergic signalling and the mobilization of lactate from glycogen stores.
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Affiliation(s)
- Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Matthias T Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Ladina Hösli
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Zoe J Looser
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Jordi Duran
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Madrid, Spain
| | - Joan J Guinovart
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Madrid, Spain
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona, Spain
| | | | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.
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26
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Gottwald EM, Schuh CD, Drücker P, Haenni D, Pearson A, Ghazi S, Bugarski M, Polesel M, Duss M, Landau EM, Kaech A, Ziegler U, Lundby AKM, Lundby C, Dittrich PS, Hall AM. The iron chelator Deferasirox causes severe mitochondrial swelling without depolarization due to a specific effect on inner membrane permeability. Sci Rep 2020; 10:1577. [PMID: 32005861 PMCID: PMC6994599 DOI: 10.1038/s41598-020-58386-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 01/15/2020] [Indexed: 12/13/2022] Open
Abstract
The iron chelator Deferasirox (DFX) causes severe toxicity in patients for reasons that were previously unexplained. Here, using the kidney as a clinically relevant in vivo model for toxicity together with a broad range of experimental techniques, including live cell imaging and in vitro biophysical models, we show that DFX causes partial uncoupling and dramatic swelling of mitochondria, but without depolarization or opening of the mitochondrial permeability transition pore. This effect is explained by an increase in inner mitochondrial membrane (IMM) permeability to protons, but not small molecules. The movement of water into mitochondria is prevented by altering intracellular osmotic gradients. Other clinically used iron chelators do not produce mitochondrial swelling. Thus, DFX causes organ toxicity due to an off-target effect on the IMM, which has major adverse consequences for mitochondrial volume regulation.
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Affiliation(s)
| | - Claus D Schuh
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Patrick Drücker
- Department of Biosystems Science and Engineering, ETH Zurich, Zurich, Switzerland
| | - Dominik Haenni
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Adam Pearson
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Susan Ghazi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | - Michael Duss
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Ehud M Landau
- Department of Chemistry, University of Zurich, Zurich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Anne K M Lundby
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Carsten Lundby
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, ETH Zurich, Zurich, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland. .,Department of Nephrology, University Hospital Zurich, Zurich, Switzerland.
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27
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Schmid F, Barrett MJP, Obrist D, Weber B, Jenny P. Red blood cells stabilize flow in brain microvascular networks. PLoS Comput Biol 2019; 15:e1007231. [PMID: 31469820 PMCID: PMC6750893 DOI: 10.1371/journal.pcbi.1007231] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 09/18/2019] [Accepted: 07/01/2019] [Indexed: 12/28/2022] Open
Abstract
Capillaries are the prime location for oxygen and nutrient exchange in all tissues. Despite their fundamental role, our knowledge of perfusion and flow regulation in cortical capillary beds is still limited. Here, we use in vivo measurements and blood flow simulations in anatomically accurate microvascular network to investigate the impact of red blood cells (RBCs) on microvascular flow. Based on these in vivo and in silico experiments, we show that the impact of RBCs leads to a bias toward equating the values of the outflow velocities at divergent capillary bifurcations, for which we coin the term “well-balanced bifurcations”. Our simulation results further reveal that hematocrit heterogeneity is directly caused by the RBC dynamics, i.e. by their unequal partitioning at bifurcations and their effect on vessel resistance. These results provide the first in vivo evidence of the impact of RBC dynamics on the flow field in the cortical microvasculature. By structural and functional analyses of our blood flow simulations we show that capillary diameter changes locally alter flow and RBC distribution. A dilation of 10% along a vessel length of 100 μm increases the flow on average by 21% in the dilated vessel downstream a well-balanced bifurcation. The number of RBCs rises on average by 27%. Importantly, RBC up-regulation proves to be more effective the more balanced the outflow velocities at the upstream bifurcation are. Taken together, we conclude that diameter changes at capillary level bear potential to locally change the flow field and the RBC distribution. Moreover, our results suggest that the balancing of outflow velocities contributes to the robustness of perfusion. Based on our in silico results, we anticipate that the bi-phasic nature of blood and small-scale regulations are essential for a well-adjusted oxygen and energy substrate supply. Glucose and oxygen are key energy sources of the brain. As energy storage capabilities are limited in the brain, a continuous supply of oxygen and glucose via the bloodstream is crucial for the brain’s functioning. The bulk of discharge occurs at the level of capillaries, which are the smallest and most frequent vessels of the cortical vasculature. Nonetheless, our understanding of perfusion and topology of the capillary bed is still limited. Here, we use in vivo two-photon based blood flow measurements and numerical simulations in large realistic microvascular networks to study the flow in the cortical microvasculature. Our results reveal that the impact of red blood cells enhances the robustness of microvascular perfusion and increases the heterogeneity in red blood cell distribution. It is well established that higher neuronal activity leads to an increase in blood flow. However, the precise regulation mechanisms and their spatial extent remain largely unknown. We show that small-scale regulations locally alter flow and red blood cell distribution. We suggest that these mechanisms are key for an efficient and flexible circulatory system. Moreover, our results reveal a novel role of the bi-phasic nature of blood.
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Affiliation(s)
- Franca Schmid
- Institute of Fluid Dynamics, ETH Zurich, Sonneggstrasse 3, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
- * E-mail:
| | - Matthew J. P. Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstrasse 190, Zurich, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Murtenstrasse 50, Bern, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstrasse 190, Zurich, Switzerland
| | - Patrick Jenny
- Institute of Fluid Dynamics, ETH Zurich, Sonneggstrasse 3, Zurich, Switzerland
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Morales-Dalmau J, Vilches C, Sanz V, de Miguel I, Rodríguez-Fajardo V, Berto P, Martínez-Lozano M, Casanovas O, Durduran T, Quidant R. Quantification of gold nanoparticle accumulation in tissue by two-photon luminescence microscopy. NANOSCALE 2019; 11:11331-11339. [PMID: 31166337 DOI: 10.1039/c9nr01198f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanomedicine has emerged as a promising strategy to address some of the limitations of traditional biomedical sensing, imaging and therapy modalities. Its applicability and efficacy are, in part, hindered by the difficulty in both controllably delivering nanoparticles to specific regions and accurately monitoring them in tissue. Gold nanoparticles are among the most extensively used inorganic nanoparticles which benefit from high biocompatibility, flexible functionalization, strong and tunable resonant absorption, and production scalability. Moreover, their capability to enhance optical fields at their plasmon resonance enables local boosting of non-linear optical processes, which are otherwise very inefficient. In particular, two-photon induced luminescence (TPL) in gold offers high signal specificity for monitoring gold nanoparticles in a biological environment. In this article, we demonstrate that TPL microscopy provides a robust sub-micron-resolution technique able to quantify accumulated gold nanorods (GNRs) both in cells and in tissues. First, the temporal accumulation of GNRs with two different surface chemistries was measured in 786-O cells during the first 24 hours of incubation, and at different nanoparticle concentrations. Subsequently, GNR accumulation in mice, 6 h and 24 hours after tail vein injection, was quantified by TPL microscopy in biopsied tissue from kidney, spleen, liver and clear cell renal cell carcinoma (ccRCC) tumors, in good agreement with inductively coupled mass spectroscopy. Our data suggest that TPL microscopy stands as a powerful tool to understand and quantify the delivery mechanisms of gold nanoparticles, highly relevant to the development of future theranostic medicines.
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Affiliation(s)
- Jordi Morales-Dalmau
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
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29
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Prange JA, Aleandri S, Komisarski M, Luciani A, Käch A, Schuh CD, Hall AM, Mezzenga R, Devuyst O, Landau EM. Overcoming Endocytosis Deficiency by Cubosome Nanocarriers. ACS APPLIED BIO MATERIALS 2019; 2:2490-2499. [DOI: 10.1021/acsabm.9b00187] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Jenny A. Prange
- Institute of Physiology, University of Zurich, Zurich 8057, Switzerland
| | - Simone Aleandri
- Department of Chemistry, University of Zurich, Zurich 8057, Switzerland
| | - Marek Komisarski
- Department of Chemistry, University of Zurich, Zurich 8057, Switzerland
| | | | - Andres Käch
- Center for Microscopy and Image Analysis, University of Zurich, Zurich 8057, Switzerland
| | | | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich 8057, Switzerland
| | - Raffaele Mezzenga
- Department of Health Sciences & Technology, ETH Zurich, Zurich 8092, Switzerland
| | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich 8057, Switzerland
| | - Ehud M. Landau
- Department of Chemistry, University of Zurich, Zurich 8057, Switzerland
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30
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Schneider MK, Ioanas HI, Xandry J, Rudin M. An in vivo wound healing model for the characterization of the angiogenic process and its modulation by pharmacological interventions. Sci Rep 2019; 9:6004. [PMID: 30979919 PMCID: PMC6461656 DOI: 10.1038/s41598-019-42479-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 03/28/2019] [Indexed: 12/13/2022] Open
Abstract
Angiogenesis during wound healing is essential for tissue repair and also affected during cancer treatment by anti-angiogenic drugs. Here, we introduce a minimally invasive wound healing model in the mouse ear to assess angiogenesis with high spatiotemporal resolution in a longitudinal manner in vivo using two-photon microscopy in mice expressing GCaMP2 in arterial endothelial cells. The development of vascular sprouts occurred in a highly orchestrated manner within a time window of 8 days following wounding. Novel sprouts developed exclusively from the distal stump of the transsected arteries, growing towards the proximal arterial stump. This was in line with the incidence of Ca2+ transients in the arterial endothelial cells, most probably a result of VEGF stimulation, which were more numerous on the distal part. Functional analysis revealed perfusion across the wound site via arterial sprouts developed between days 6 and 8 following the incision. At day 8, proximal and distal arteries were structurally and functionally connected, though only 2/3 of all sprouts detected were actually perfused. Treatment with the FDA approved drug, sunitinib, the preclinical drug AZD4547, as well as with the combination of the two agents had significant effects on both structural and functional readouts of neo-angiogenesis. The simplicity and high reproducibility of the model makes it an attractive tool for elucidating migratory activity, phenotype and functionality of endothelial cells during angiogenesis and for evaluating specific anti-angiogenic drug interventions.
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Affiliation(s)
- Martin Karl Schneider
- Institute for Biomedical Engineering and Functional Pharmacology, ETH Zurich and University of Zurich, 8093, Zurich, Switzerland
| | - Horea-Ioan Ioanas
- Institute for Biomedical Engineering and Functional Pharmacology, ETH Zurich and University of Zurich, 8093, Zurich, Switzerland
| | - Jael Xandry
- Institute for Biomedical Engineering and Functional Pharmacology, ETH Zurich and University of Zurich, 8093, Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering and Functional Pharmacology, ETH Zurich and University of Zurich, 8093, Zurich, Switzerland.
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31
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Esipova TV, Barrett MJP, Erlebach E, Masunov AE, Weber B, Vinogradov SA. Oxyphor 2P: A High-Performance Probe for Deep-Tissue Longitudinal Oxygen Imaging. Cell Metab 2019; 29:736-744.e7. [PMID: 30686745 PMCID: PMC6402963 DOI: 10.1016/j.cmet.2018.12.022] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 10/22/2018] [Accepted: 12/26/2018] [Indexed: 01/09/2023]
Abstract
Quantitative imaging of oxygen distributions in tissue can provide invaluable information about metabolism in normal and diseased states. Two-photon phosphorescence lifetime microscopy (2PLM) has been developed to perform measurements of oxygen in vivo with micron-scale resolution in 3D; however, the method's potential has not yet been fully realized due to the limitations of current phosphorescent probe technology. Here, we report a new sensor, Oxyphor 2P, that enables oxygen microscopy twice as deep (up to 600 μm below the tissue surface) and with ∼60 times higher speed than previously possible. Oxyphor 2P allows longitudinal oxygen measurements without having to inject the probe directly into the imaged region. As proof of principle, we monitored oxygen dynamics for days following micro-stroke induced by occlusion of a single capillary in the mouse brain. Oxyphor 2P opens up new possibilities for studies of tissue metabolic states using 2PLM in a wide range of biomedical research areas.
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Affiliation(s)
- Tatiana V Esipova
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew J P Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Zürich 8057, Switzerland
| | - Eva Erlebach
- Institute of Pharmacology and Toxicology, University of Zurich, Zürich 8057, Switzerland; Neuroscience Center, University of Zurich, Zurich 8057, Switzerland
| | - Artëm E Masunov
- NanoScience Technology Center, Department of Chemistry, University of Central Florida, Orlando, FL 32826, USA; School of Modeling, Simulation and Training, University of Central Florida, Orlando, FL 32826, USA; National Research Nuclear University MEPhI, Kashirskoye Shosse 31, Moscow 115409, Russia; South Ural State University, Lenin Pr. 76, Chelyabinsk 454080, Russia
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zürich 8057, Switzerland; Neuroscience Center, University of Zurich, Zurich 8057, Switzerland.
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Baeza-Lehnert F, Saab AS, Gutiérrez R, Larenas V, Díaz E, Horn M, Vargas M, Hösli L, Stobart J, Hirrlinger J, Weber B, Barros LF. Non-Canonical Control of Neuronal Energy Status by the Na + Pump. Cell Metab 2019; 29:668-680.e4. [PMID: 30527744 DOI: 10.1016/j.cmet.2018.11.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 08/01/2018] [Accepted: 11/12/2018] [Indexed: 12/31/2022]
Abstract
Neurons have limited intracellular energy stores but experience acute and unpredictable increases in energy demand. To better understand how these cells repeatedly transit from a resting to active state without undergoing metabolic stress, we monitored their early metabolic response to neurotransmission using ion-sensitive probes and FRET sensors in vitro and in vivo. A short theta burst triggered immediate Na+ entry, followed by a delayed stimulation of the Na+/K+ ATPase pump. Unexpectedly, cytosolic ATP and ADP levels were unperturbed across a wide range of physiological workloads, revealing strict flux coupling between the Na+ pump and mitochondria. Metabolic flux measurements revealed a "priming" phase of mitochondrial energization by pyruvate, whereas glucose consumption coincided with delayed Na+ pump stimulation. Experiments revealed that the Na+ pump plays a permissive role for mitochondrial ATP production and glycolysis. We conclude that neuronal energy homeostasis is not mediated by adenine nucleotides or by Ca2+, but by a mechanism commanded by the Na+ pump.
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Affiliation(s)
- Felipe Baeza-Lehnert
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University and ETH Zurich, Switzerland; Neuroscience Center Zurich, Zurich, Switzerland
| | - Robin Gutiérrez
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - Valeria Larenas
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile
| | - Esteban Díaz
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - Melanie Horn
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile
| | - Miriam Vargas
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - Ladina Hösli
- Institute of Pharmacology and Toxicology, University and ETH Zurich, Switzerland; Neuroscience Center Zurich, Zurich, Switzerland
| | - Jillian Stobart
- Institute of Pharmacology and Toxicology, University and ETH Zurich, Switzerland; Neuroscience Center Zurich, Zurich, Switzerland
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany; Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University and ETH Zurich, Switzerland; Neuroscience Center Zurich, Zurich, Switzerland
| | - L Felipe Barros
- Centro de Estudios Científicos (CECs), Casilla 1469, 5110466 Valdivia, Chile.
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Eibl M, Weng D, Hakert H, Kolb JP, Pfeiffer T, Hundt JE, Huber R, Karpf S. Wavelength agile multi-photon microscopy with a fiber amplified diode laser. BIOMEDICAL OPTICS EXPRESS 2018; 9:6273-6282. [PMID: 31065428 PMCID: PMC6490994 DOI: 10.1364/boe.9.006273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/22/2018] [Accepted: 10/22/2018] [Indexed: 06/09/2023]
Abstract
Multi-photon microscopy is a powerful tool in biomolecular research. Less complex and more cost effective excitation light sources will make this technique accessible to a broader community. Semiconductor diode seeded fiber lasers have proven to be especially robust, low cost and easy to use. However, their wavelength tuning range is often limited, so only a limited number of fluorophores can be accessed. Therefore, different approaches have been proposed to extend the spectral coverage of these lasers. Recently, we showed that four-wave mixing (FWM) assisted stimulated Raman scattering (SRS) can be harnessed to red-shift high power pulses from 1064 nm to a narrowband output at 1122 nm and 1186 nm and therefore extend the number of accessible fluorophores. In this contribution, we show the applicability of all three wavelengths for multi-photon microscopy and analyze the performance.
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Affiliation(s)
- Matthias Eibl
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
| | - Daniel Weng
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
| | - Hubertus Hakert
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
| | - Tom Pfeiffer
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
| | - Jennifer E. Hundt
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, 23538 Lübeck, Germany
| | - Robert Huber
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
| | - Sebastian Karpf
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
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34
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Looser ZJ, Barrett MJP, Hirrlinger J, Weber B, Saab AS. Intravitreal AAV-Delivery of Genetically Encoded Sensors Enabling Simultaneous Two-Photon Imaging and Electrophysiology of Optic Nerve Axons. Front Cell Neurosci 2018; 12:377. [PMID: 30405358 PMCID: PMC6205974 DOI: 10.3389/fncel.2018.00377] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/03/2018] [Indexed: 11/21/2022] Open
Abstract
Myelination of axons by oligodendrocytes is a key feature of the remarkably fast operating CNS. Oligodendrocytes not only tune axonal conduction speed but are also suggested to maintain long-term axonal integrity by providing metabolic support to the axons they ensheath. However, how myelinating oligodendrocytes impact axonal energy homeostasis remains poorly understood and difficult to investigate. Here, we provide a method of how to study electrically active myelinated axons expressing genetically encoded sensors by combining electrophysiology and two-photon imaging of acutely isolated optic nerves. We show that intravitreal adeno-associated viral (AAV) vector delivery is an efficient tool to achieve functional sensor expression in optic nerve axons, which is demonstrated by measuring axonal ATP dynamics following AAV-mediated sensor expression. This novel approach allows for fast expression of any optical sensor of interest to be studied in optic nerve axons without the need to go through the laborious process of producing new transgenic mouse lines. Viral-mediated biosensor expression in myelinated axons and the subsequent combination of nerve recordings and sensor imaging outlines a powerful method to investigate oligodendroglial support functions and to further interrogate cellular mechanisms governing axonal energy homeostasis under physiological and pathological conditions.
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Affiliation(s)
- Zoe J. Looser
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Matthew J. P. Barrett
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Bruno Weber
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Aiman S. Saab
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
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35
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Lücker A, Secomb TW, Barrett MJP, Weber B, Jenny P. The Relation Between Capillary Transit Times and Hemoglobin Saturation Heterogeneity. Part 2: Capillary Networks. Front Physiol 2018; 9:1296. [PMID: 30298017 PMCID: PMC6160581 DOI: 10.3389/fphys.2018.01296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 08/29/2018] [Indexed: 12/22/2022] Open
Abstract
Brain metabolism is highly dependent on continuous oxygen supply. Cortical microvascular networks exhibit heterogeneous blood flow, leading to non-uniform tissue oxygenation and capillary hemoglobin saturation. We recently proposed capillary outflow saturation heterogeneity (COSH) to represent effects of heterogeneity on oxygen supply to tissue regions most vulnerable to hypoxia, and showed that diffusive oxygen exchange among red blood cells within capillaries and among capillaries (diffusive interaction) significantly reduces COSH in simplified geometrical configurations. Here, numerical simulations of oxygen transport in capillary network geometries derived from mouse somatosensory cortex are presented. Diffusive interaction was found to reduce COSH by 41 to 62% compared to simulations where diffusive interaction was excluded. Hemoglobin saturation drop across the microvascular network is strongly correlated with red blood cell transit time, but the coefficient of variation of saturation drop is approximately one third lower. Unexpectedly, the radius of the tissue cylinder supplied by a capillary correlates weakly with the anatomical tissue cylinder radius, but strongly with hemoglobin saturation. Thus, diffusive interaction contributes greatly to the microcirculation's ability to achieve tissue oxygenation, despite heterogeneous capillary transit time and hematocrit distribution. These findings provide insight into the effects of cerebral small vessel disease on tissue oxygenation and brain function.
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Affiliation(s)
- Adrien Lücker
- Department of Mechanical and Process Engineering, Institute of Fluid Dynamics, ETH Zürich, Zurich, Switzerland
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, United States
| | - Matthew J P Barrett
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zürich, Zurich, Switzerland
| | - Patrick Jenny
- Department of Mechanical and Process Engineering, Institute of Fluid Dynamics, ETH Zürich, Zurich, Switzerland
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36
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Bugarski M, Martins JR, Haenni D, Hall AM. Multiphoton imaging reveals axial differences in metabolic autofluorescence signals along the kidney proximal tubule. Am J Physiol Renal Physiol 2018; 315:F1613-F1625. [PMID: 30132348 DOI: 10.1152/ajprenal.00165.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Kidney proximal tubules (PTs) are densely packed with mitochondria, and defects in mitochondrial function are implicated in many kidney diseases. However, little is known about intrinsic mitochondrial function within PT cells. Here, using intravital multiphoton microscopy and live slices of mouse kidney cortex, we show that autofluorescence signals provide important functional readouts of redox state and substrate metabolism and that there are striking axial differences in signals along the PT. Mitochondrial NAD(P)H intensity was similar in both PT segment (S)1 and S2 and was sensitive to changes in respiratory chain (RC) redox state, whereas cytosolic NAD(P)H intensity was significantly higher in S2. Mitochondrial NAD(P)H increased in response to lactate and butyrate but decreased in response to glutamine and glutamate. Cytosolic NAD(P)H was sensitive to lactate and pyruvate and decreased dramatically in S2 in response to inhibition of glucose metabolism. Mitochondrial flavoprotein (FP) intensity was markedly higher in S2 than in S1 but was insensitive to changes in RC redox state. Mitochondrial FP signal increased in response to palmitate but decreased in response to glutamine and glutamate. Fluorescence lifetime decays were similar in both S1 and S2, suggesting that intensity differences are explained by differences in abundance of the same molecular species. Expression levels of known fluorescent mitochondrial FPs were higher in S2 than S1. In summary, substantial metabolic information can be obtained in kidney tissue using a label-free live imaging approach, and our findings suggest that metabolism is tailored to the specialized functions of S1 and S2 PT segments.
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Affiliation(s)
- Milica Bugarski
- Institute of Anatomy, University of Zurich , Zurich , Switzerland
| | | | - Dominik Haenni
- Institute of Anatomy, University of Zurich , Zurich , Switzerland.,Center for Microscopy and Image Analysis, University of Zurich , Zurich , Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich , Zurich , Switzerland.,Department of Nephrology, University Hospital Zurich , Zurich , Switzerland
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37
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Galiñanes GL, Marchand PJ, Turcotte R, Pellat S, Ji N, Huber D. Optical alignment device for two-photon microscopy. BIOMEDICAL OPTICS EXPRESS 2018; 9:3624-3639. [PMID: 30338144 PMCID: PMC6191613 DOI: 10.1364/boe.9.003624] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 05/10/2023]
Abstract
Two-photon excitation fluorescence microscopy has revolutionized our understanding of brain structure and function through the high resolution and large penetration depth it offers. Investigating neural structures in vivo requires gaining optical access to the brain, which is typically achieved by replacing a part of the skull with one or several layers of cover glass windows. To compensate for the spherical aberrations caused by the presence of these layers of glass, collar-correction objectives are typically used. However, the efficiency of this correction has been shown to depend significantly on the tilt angle between the glass window surface and the optical axis of the imaging system. Here, we first expand these observations and characterize the effect of the tilt angle on the collected fluorescence signal with thicker windows (double cover slide) and compare these results with an objective devoid of collar-correction. Second, we present a simple optical alignment device designed to rapidly minimize the tilt angle in vivo and align the optical axis of the microscope perpendicularly to the glass window to an angle below 0.25°, thereby significantly improving the imaging quality. Finally, we describe a tilt-correction procedure for users in an in vivo setting, enabling the accurate alignment with a resolution of <0.2° in only few iterations.
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Affiliation(s)
- Gregorio L. Galiñanes
- Department of Basic Neurosciences, University of Geneva, Rue Michel Servet 1, 1206 Geneva,
Switzerland
| | - Paul J. Marchand
- Department of Basic Neurosciences, University of Geneva, Rue Michel Servet 1, 1206 Geneva,
Switzerland
| | - Raphaël Turcotte
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147,
USA
- Current address: Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT,
UK
| | - Sebastien Pellat
- Department of Basic Neurosciences, University of Geneva, Rue Michel Servet 1, 1206 Geneva,
Switzerland
| | - Na Ji
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147,
USA
- Current address: Department of Physics, Department of Molecular & Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720,
USA
| | - Daniel Huber
- Department of Basic Neurosciences, University of Geneva, Rue Michel Servet 1, 1206 Geneva,
Switzerland
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38
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Stobart JL, Ferrari KD, Barrett MJP, Glück C, Stobart MJ, Zuend M, Weber B. Cortical Circuit Activity Evokes Rapid Astrocyte Calcium Signals on a Similar Timescale to Neurons. Neuron 2018; 98:726-735.e4. [PMID: 29706581 DOI: 10.1016/j.neuron.2018.03.050] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/12/2018] [Accepted: 03/30/2018] [Indexed: 12/22/2022]
Abstract
Sensory stimulation evokes intracellular calcium signals in astrocytes; however, the timing of these signals is disputed. Here, we used novel combinations of genetically encoded calcium indicators for concurrent two-photon imaging of cortical astrocytes and neurons in awake mice during whisker deflection. We identified calcium responses in both astrocyte processes and endfeet that rapidly followed neuronal events (∼120 ms after). These fast astrocyte responses were largely independent of IP3R2-mediated signaling and known neuromodulator activity (acetylcholine, serotonin, and norepinephrine), suggesting that they are evoked by local synaptic activity. The existence of such rapid signals implies that astrocytes are fast enough to play a role in synaptic modulation and neurovascular coupling. VIDEO ABSTRACT.
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Affiliation(s)
- Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Matthew J P Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Chaim Glück
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Michael J Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center, University and ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
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Eibl M, Karpf S, Weng D, Hakert H, Pfeiffer T, Kolb JP, Huber R. Single pulse two photon fluorescence lifetime imaging (SP-FLIM) with MHz pixel rate. BIOMEDICAL OPTICS EXPRESS 2017; 8:3132-3142. [PMID: 28717558 PMCID: PMC5508819 DOI: 10.1364/boe.8.003132] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/05/2017] [Accepted: 05/08/2017] [Indexed: 05/18/2023]
Abstract
Two-photon-excited fluorescence lifetime imaging microscopy (FLIM) is a chemically specific 3-D sensing modality providing valuable information about the microstructure, composition and function of a sample. However, a more widespread application of this technique is hindered by the need for a sophisticated ultra-short pulse laser source and by speed limitations of current FLIM detection systems. To overcome these limitations, we combined a robust sub-nanosecond fiber laser as the excitation source with high analog bandwidth detection. Due to the long pulse length in our configuration, more fluorescence photons are generated per pulse, which allows us to derive the lifetime with a single excitation pulse only. In this paper, we show high quality FLIM images acquired at a pixel rate of 1 MHz. This approach is a promising candidate for an easy-to-use and benchtop FLIM system to make this technique available to a wider research community.
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Affiliation(s)
- Matthias Eibl
- Institut für Biomedizinische Optik, Universität zu Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Sebastian Karpf
- Department of Electrical Engineering, University of California, Los Angeles, CA 90095, USA
| | - Daniel Weng
- Institut für Biomedizinische Optik, Universität zu Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Hubertus Hakert
- Institut für Biomedizinische Optik, Universität zu Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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Schuh C, Haenni D, Craigie E, Ziegler U, Weber B, Devuyst O, Hall AM. Long wavelength multiphoton excitation is advantageous for intravital kidney imaging. Kidney Int 2016; 89:712-9. [DOI: 10.1038/ki.2015.323] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/14/2015] [Accepted: 09/03/2015] [Indexed: 11/09/2022]
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Mächler P, Wyss MT, Elsayed M, Stobart J, Gutierrez R, von Faber-Castell A, Kaelin V, Zuend M, San Martín A, Romero-Gómez I, Baeza-Lehnert F, Lengacher S, Schneider BL, Aebischer P, Magistretti PJ, Barros LF, Weber B. In Vivo Evidence for a Lactate Gradient from Astrocytes to Neurons. Cell Metab 2016; 23:94-102. [PMID: 26698914 DOI: 10.1016/j.cmet.2015.10.010] [Citation(s) in RCA: 395] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/21/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022]
Abstract
Investigating lactate dynamics in brain tissue is challenging, partly because in vivo data at cellular resolution are not available. We monitored lactate in cortical astrocytes and neurons of mice using the genetically encoded FRET sensor Laconic in combination with two-photon microscopy. An intravenous lactate injection rapidly increased the Laconic signal in both astrocytes and neurons, demonstrating high lactate permeability across tissue. The signal increase was significantly smaller in astrocytes, pointing to higher basal lactate levels in these cells, confirmed by a one-point calibration protocol. Trans-acceleration of the monocarboxylate transporter with pyruvate was able to reduce intracellular lactate in astrocytes but not in neurons. Collectively, these data provide in vivo evidence for a lactate gradient from astrocytes to neurons. This gradient is a prerequisite for a carrier-mediated lactate flux from astrocytes to neurons and thus supports the astrocyte-neuron lactate shuttle model, in which astrocyte-derived lactate acts as an energy substrate for neurons.
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Affiliation(s)
- Philipp Mächler
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Matthias T Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Maha Elsayed
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Jillian Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Robin Gutierrez
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Centro de Estudios Científicos, Valdivia 5110466, Chile
| | | | - Vincens Kaelin
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | | | | | | | - Sylvain Lengacher
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Bernard L Schneider
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Patrick Aebischer
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Pierre J Magistretti
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | | | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland.
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Pavone FS, Hillman E, Leblond F, Shoham S. Introduction to the optics and the brain 2015 feature issue. BIOMEDICAL OPTICS EXPRESS 2015; 6:4992-4993. [PMID: 26713211 PMCID: PMC4679271 DOI: 10.1364/boe.6.004992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Indexed: 06/05/2023]
Abstract
The Optics and the Brain conference brought together leaders in the neuroscience optics field whose contributions are significantly advancing the state of the art in biological and medical research through the development and implementation of innovative optical technologies. In this conference, the latest advances in neurophotonic imaging, novel optical modulation approaches and applications across scales from small organisms to clinical settings were presented.
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