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Southwell DG. Interneuron Transplantation for Drug-Resistant Epilepsy. Neurosurg Clin N Am 2024; 35:151-160. [PMID: 38000838 DOI: 10.1016/j.nec.2023.08.006] [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] [Indexed: 11/26/2023]
Abstract
Current epilepsy surgical techniques, such as brain resection, laser ablation, and neurostimulation, target seizure networks macroscopically, and they may yield an unfavorable balance between seizure reduction, procedural invasiveness, and neurologic morbidity. The transplantation of GABAergic interneurons is a regenerative technique for altering neural inhibition in cortical circuits, with potential as an alternative and minimally invasive approach to epilepsy treatment. This article (1) reviews some of the preclinical evidence supporting interneuron transplantation as an epilepsy therapy, (2) describes a first-in-human study of interneuron transplantation for epilepsy, and (3) considers knowledge gaps that stand before the effective clinical application of this novel treatment.
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Affiliation(s)
- Derek G Southwell
- Department of Neurosurgery, Graduate Program in Neurobiology, Duke University, DUMC 3807, 200 Trent Drive, Durham, NC 27710, USA.
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2
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The role of GABAergic signalling in neurodevelopmental disorders. Nat Rev Neurosci 2021; 22:290-307. [PMID: 33772226 PMCID: PMC9001156 DOI: 10.1038/s41583-021-00443-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2021] [Indexed: 02/08/2023]
Abstract
GABAergic inhibition shapes the connectivity, activity and plasticity of the brain. A series of exciting new discoveries provides compelling evidence that disruptions in a number of key facets of GABAergic inhibition have critical roles in the aetiology of neurodevelopmental disorders (NDDs). These facets include the generation, migration and survival of GABAergic neurons, the formation of GABAergic synapses and circuit connectivity, and the dynamic regulation of the efficacy of GABAergic signalling through neuronal chloride transporters. In this Review, we discuss recent work that elucidates the functions and dysfunctions of GABAergic signalling in health and disease, that uncovers the contribution of GABAergic neural circuit dysfunction to NDD aetiology and that leverages such mechanistic insights to advance precision medicine for the treatment of NDDs.
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3
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Harward SC, Southwell DG. Interneuron transplantation: a prospective surgical therapy for medically refractory epilepsy. Neurosurg Focus 2021; 48:E18. [PMID: 32234982 DOI: 10.3171/2020.2.focus19955] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 02/04/2020] [Indexed: 11/06/2022]
Abstract
Excitatory-inhibitory imbalance is central to epilepsy pathophysiology. Current surgical therapies for epilepsy, such as brain resection, laser ablation, and neurostimulation, target epileptic networks on macroscopic scales, without directly correcting the circuit-level aberrations responsible for seizures. The transplantation of inhibitory cortical interneurons represents a novel neurobiological method for modifying recipient neural circuits in a physiologically corrective manner. Transplanted immature interneurons have been found to disperse in the recipient brain parenchyma, where they develop elaborate structural morphologies, express histochemical markers of mature interneurons, and form functional inhibitory synapses onto recipient neurons. Transplanted interneurons also augment synaptic inhibition and alter recipient neural network synchrony, two physiological processes disrupted in various epilepsies. In rodent models of epilepsy, interneuron transplantation corrects recipient seizure phenotypes and associated behavioral abnormalities. As such, interneuron transplantation may represent a novel neurobiological approach to the surgical treatment of human epilepsy. Here, the authors describe the preclinical basis for applying interneuron transplantation to human epilepsy, discuss its potential clinical applications, and consider the translational hurdles to its development as a surgical therapy.
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Affiliation(s)
| | - Derek G Southwell
- Departments of1Neurosurgery and.,2Neurology.,3Graduate Program in Neurobiology; Duke University, Durham, North Carolina
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Mancia Leon WR, Spatazza J, Rakela B, Chatterjee A, Pande V, Maniatis T, Hasenstaub AR, Stryker MP, Alvarez-Buylla A. Clustered gamma-protocadherins regulate cortical interneuron programmed cell death. eLife 2020; 9:e55374. [PMID: 32633719 PMCID: PMC7373431 DOI: 10.7554/elife.55374] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/06/2020] [Indexed: 01/19/2023] Open
Abstract
Cortical function critically depends on inhibitory/excitatory balance. Cortical inhibitory interneurons (cINs) are born in the ventral forebrain and migrate into cortex, where their numbers are adjusted by programmed cell death. Here, we show that loss of clustered gamma protocadherins (Pcdhg), but not of genes in the alpha or beta clusters, increased dramatically cIN BAX-dependent cell death in mice. Surprisingly, electrophysiological and morphological properties of Pcdhg-deficient and wild-type cINs during the period of cIN cell death were indistinguishable. Co-transplantation of wild-type with Pcdhg-deficient interneuron precursors further reduced mutant cIN survival, but the proportion of mutant and wild-type cells undergoing cell death was not affected by their density. Transplantation also allowed us to test for the contribution of Pcdhg isoforms to the regulation of cIN cell death. We conclude that Pcdhg, specifically Pcdhgc3, Pcdhgc4, and Pcdhgc5, play a critical role in regulating cIN survival during the endogenous period of programmed cIN death.
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Affiliation(s)
- Walter R Mancia Leon
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San FranciscoSan FranciscoUnited States
| | - Julien Spatazza
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San FranciscoSan FranciscoUnited States
| | - Benjamin Rakela
- Department of Physiology and Center for Integrative Neuroscience, University of California, San FranciscoSan FranciscoUnited States
| | - Ankita Chatterjee
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San FranciscoSan FranciscoUnited States
| | - Viraj Pande
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San FranciscoSan FranciscoUnited States
| | - Tom Maniatis
- Department of Biochemistry and Molecular Biophysics, Columbia UniversityNew YorkUnited States
| | - Andrea R Hasenstaub
- Department of Otolaryngology-Head and Neck Surgery, University of California, San FranciscoSan FranciscoUnited States
- Kavli Institute for Fundamental Neuroscience, University of California, San FranciscoSan FranciscoUnited States
| | - Michael P Stryker
- Department of Physiology and Center for Integrative Neuroscience, University of California, San FranciscoSan FranciscoUnited States
- Kavli Institute for Fundamental Neuroscience, University of California, San FranciscoSan FranciscoUnited States
| | - Arturo Alvarez-Buylla
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San FranciscoSan FranciscoUnited States
- Kavli Institute for Fundamental Neuroscience, University of California, San FranciscoSan FranciscoUnited States
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Southwell DG, Seifikar H, Malik R, Lavi K, Vogt D, Rubenstein JL, Sohal VS. Interneuron Transplantation Rescues Social Behavior Deficits without Restoring Wild-Type Physiology in a Mouse Model of Autism with Excessive Synaptic Inhibition. J Neurosci 2020; 40:2215-2227. [PMID: 31988060 PMCID: PMC7083289 DOI: 10.1523/jneurosci.1063-19.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 12/11/2019] [Accepted: 12/31/2019] [Indexed: 11/21/2022] Open
Abstract
Manipulations that enhance GABAergic inhibition have been associated with improved behavioral phenotypes in autism models, suggesting that autism may be treated by correcting underlying deficits of inhibition. Interneuron transplantation is a method for increasing recipient synaptic inhibition, and it has been considered a prospective therapy for conditions marked by deficient inhibition, including neuropsychiatric disorders. It is unknown, however, whether interneuron transplantation may be therapeutically effective only for conditions marked by reduced inhibition, and it is also unclear whether transplantation improves behavioral phenotypes solely by normalizing underlying circuit defects. To address these questions, we studied the effects of interneuron transplantation in male and female mice lacking the autism-associated gene, Pten, in GABAergic interneurons. Pten mutant mice exhibit social behavior deficits, elevated synaptic inhibition in prefrontal cortex, abnormal baseline and social interaction-evoked electroencephalogram (EEG) signals, and an altered composition of cortical interneuron subtypes. Transplantation of wild-type embryonic interneurons from the medial ganglionic eminence into the prefrontal cortex of neonatal Pten mutants rescued social behavior despite exacerbating excessive levels of synaptic inhibition. Furthermore, transplantation did not normalize recipient EEG signals measured during baseline states. Interneuron transplantation can thus correct behavioral deficits even when those deficits are associated with elevated synaptic inhibition. Moreover, transplantation does not exert therapeutic effects solely by restoring wild-type circuit states. Our findings indicate that interneuron transplantation could offer a novel cell-based approach to autism treatment while challenging assumptions that effective therapies must reverse underlying circuit defects.SIGNIFICANCE STATEMENT Imbalances between neural excitation and inhibition are hypothesized to contribute to the pathophysiology of autism. Interneuron transplantation is a method for altering recipient inhibition, and it has been considered a prospective therapy for neuropsychiatric disorders, including autism. Here we examined the behavioral and physiological effects of interneuron transplantation in a mouse genetic model of autism. They demonstrate that transplantation rescues recipient social interaction deficits without correcting a common measure of recipient inhibition, or circuit-level physiological measures. These findings demonstrate that interneuron transplantation can exert therapeutic behavioral effects without necessarily restoring wild-type circuit states, while highlighting the potential of interneuron transplantation as an autism therapy.
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Affiliation(s)
- Derek G Southwell
- Department of Neurological Surgery,
- Weill Institute for Neurosciences
- Kavli Institute for Fundamental Neuroscience
| | - Helia Seifikar
- Weill Institute for Neurosciences
- Kavli Institute for Fundamental Neuroscience
- Sloan Swartz Center for Theoretical Neurobiology, and
- Department of Psychiatry, University of California, San Francisco, San Francisco, California 94143
| | - Ruchi Malik
- Weill Institute for Neurosciences
- Kavli Institute for Fundamental Neuroscience
- Sloan Swartz Center for Theoretical Neurobiology, and
- Department of Psychiatry, University of California, San Francisco, San Francisco, California 94143
| | - Karen Lavi
- Weill Institute for Neurosciences
- Kavli Institute for Fundamental Neuroscience
- Sloan Swartz Center for Theoretical Neurobiology, and
- Department of Psychiatry, University of California, San Francisco, San Francisco, California 94143
| | - Daniel Vogt
- Weill Institute for Neurosciences
- Kavli Institute for Fundamental Neuroscience
- Department of Psychiatry, University of California, San Francisco, San Francisco, California 94143
| | - John L Rubenstein
- Weill Institute for Neurosciences
- Kavli Institute for Fundamental Neuroscience
- Department of Psychiatry, University of California, San Francisco, San Francisco, California 94143
| | - Vikaas S Sohal
- Weill Institute for Neurosciences,
- Kavli Institute for Fundamental Neuroscience
- Sloan Swartz Center for Theoretical Neurobiology, and
- Department of Psychiatry, University of California, San Francisco, San Francisco, California 94143
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Bragado Alonso S, Reinert JK, Marichal N, Massalini S, Berninger B, Kuner T, Calegari F. An increase in neural stem cells and olfactory bulb adult neurogenesis improves discrimination of highly similar odorants. EMBO J 2019; 38:e98791. [PMID: 30643018 PMCID: PMC6418468 DOI: 10.15252/embj.201798791] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 01/17/2023] Open
Abstract
Adult neurogenesis is involved in cognitive performance but studies that manipulated this process to improve brain function are scarce. Here, we characterized a genetic mouse model in which neural stem cells (NSC) of the subventricular zone (SVZ) were temporarily expanded by conditional expression of the cell cycle regulators Cdk4/cyclinD1, thus increasing neurogenesis. We found that supernumerary neurons matured and integrated in the olfactory bulb similarly to physiologically generated newborn neurons displaying a correct expression of molecular markers, morphology and electrophysiological activity. Olfactory performance upon increased neurogenesis was unchanged when mice were tested on relatively easy tasks using distinct odor stimuli. In contrast, intriguingly, increasing neurogenesis improved the discrimination ability of mice when challenged with a difficult task using mixtures of highly similar odorants. Together, our study provides a mammalian model to control the expansion of somatic stem cells that can in principle be applied to any tissue for basic research and models of therapy. By applying this to NSC of the SVZ, we highlighted the importance of adult neurogenesis to specifically improve performance in a challenging olfactory task.
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Affiliation(s)
- Sara Bragado Alonso
- CRTD Center for Regenerative Therapies Dresden, School of Medicine, TU Dresden, Dresden, Germany
| | - Janine K Reinert
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Nicolas Marichal
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Simone Massalini
- CRTD Center for Regenerative Therapies Dresden, School of Medicine, TU Dresden, Dresden, Germany
| | - Benedikt Berninger
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
- Centre for Developmental Neurobiology and MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Federico Calegari
- CRTD Center for Regenerative Therapies Dresden, School of Medicine, TU Dresden, Dresden, Germany
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Vesicular GABA Transporter Is Necessary for Transplant-Induced Critical Period Plasticity in Mouse Visual Cortex. J Neurosci 2019; 39:2635-2648. [PMID: 30705101 DOI: 10.1523/jneurosci.1253-18.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/14/2022] Open
Abstract
The maturation of GABAergic inhibitory circuits is necessary for the onset of the critical period for ocular dominance plasticity (ODP) in the postnatal visual cortex (Hensch, 2005; Espinosa and Stryker, 2012). When it is deficient, the critical period does not start. When inhibitory maturation or signaling is precocious, it induces a precocious critical period. Heterochronic transplantation of GABAergic interneuron precursors derived from the medial ganglionic eminence (MGE) can induce a second period of functional plasticity in the visual cortex (Southwell et al., 2010). Although the timing of MGE transplantation-induced plasticity is dictated by the maturation of the transplanted cells, its mechanisms remain largely unknown. Here, we sought to test the effect of blocking vesicular GABA loading and subsequent release by transplanted interneurons on the ability to migrate, integrate, and induce plasticity in the host circuitry. We show that MGE cells taken from male and female donors that lack vesicular GABA transporter (Vgat) expression disperse and differentiate into somatostatin- and parvalbumin-expressing interneurons upon heterochronic transplantation in the postnatal mouse cortex. Although transplanted Vgat mutant interneurons come to express mature interneuron markers and display electrophysiological properties similar to those of control cells, their morphology is significantly more complex. Significantly, Vgat mutant MGE transplants fail to induce ODP, demonstrating the pivotal role of vesicular GABAergic transmission for MGE transplantation-induced plasticity in the postnatal mouse visual cortex.SIGNIFICANCE STATEMENT Embryonic inhibitory neurons thrive when transplanted into postnatal brains, migrating and differentiating in the host as they would have done if left in the donor. Once integrated into the host, these new neurons can have profound effects. For example, in the visual cortex, such neurons induce a second critical period of activity-dependent plasticity when they reach the appropriate stage of development. The cellular mechanism by which these transplanted GABAergic interneurons induce plasticity is unknown. Here, we show that transplanted interneurons that are unable to fill synaptic vesicles with GABA migrate and integrate into the host circuit, but they do not induce a second period of plasticity. These data suggest a role for the vesicular GABA transporter in transplantation-mediated plasticity.
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Bradshaw KP, Figueroa Velez DX, Habeeb M, Gandhi SP. Precocious deposition of perineuronal nets on Parvalbumin inhibitory neurons transplanted into adult visual cortex. Sci Rep 2018; 8:7480. [PMID: 29748633 PMCID: PMC5945847 DOI: 10.1038/s41598-018-25735-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 04/23/2018] [Indexed: 11/14/2022] Open
Abstract
The end of the critical period for primary visual cortex (V1) coincides with the deposition of perineuronal nets (PNN) onto Parvalbumin (PV) inhibitory neurons. Recently, we found that transplantation of embryonic inhibitory neurons into adult V1 reinstates a new critical period. Here we used Wisteria Floribunda Agglutinin (WFA) staining to compare the deposition of PNNs onto neurons during normal development and following transplantation at equivalent cell ages. In accord with previous findings, PV and PNN expression increases from negligible levels at postnatal day 14 (P14) to mature levels by P70. In contrast to P14, PNNs are found on transplanted PV neurons by 21 days after transplantation and persist to 105 days after transplantation. This precocious deposition was specific to PV neurons and excluded transplanted neurons expressing Somatostatin. Notably, the onset of PV expression in transplanted inhibitory neurons follows the timing of PV expression in juvenile V1. Moreover, transplantation has no discernible effect on host PNNs. The precocious deposition of PNNs onto transplanted PV neurons suggests that PNN expression identified by WFA does not reflect neuronal maturity and may be an inaccurate marker for transplant-induced plasticity of cortical circuits.
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Affiliation(s)
- Karen P Bradshaw
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697-4550, USA
| | - Dario X Figueroa Velez
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697-4550, USA
| | - Mariyam Habeeb
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697-4550, USA
| | - Sunil P Gandhi
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697-4550, USA. .,Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, 92697-4550, USA.
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Grade S, Götz M. Neuronal replacement therapy: previous achievements and challenges ahead. NPJ Regen Med 2017; 2:29. [PMID: 29302363 PMCID: PMC5677983 DOI: 10.1038/s41536-017-0033-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/22/2017] [Accepted: 09/25/2017] [Indexed: 12/26/2022] Open
Abstract
Lifelong neurogenesis and incorporation of newborn neurons into mature neuronal circuits operates in specialized niches of the mammalian brain and serves as role model for neuronal replacement strategies. However, to which extent can the remaining brain parenchyma, which never incorporates new neurons during the adulthood, be as plastic and readily accommodate neurons in networks that suffered neuronal loss due to injury or neurological disease? Which microenvironment is permissive for neuronal replacement and synaptic integration and which cells perform best? Can lost function be restored and how adequate is the participation in the pre-existing circuitry? Could aberrant connections cause malfunction especially in networks dominated by excitatory neurons, such as the cerebral cortex? These questions show how important connectivity and circuitry aspects are for regenerative medicine, which is the focus of this review. We will discuss the impressive advances in neuronal replacement strategies and success from exogenous as well as endogenous cell sources. Both have seen key novel technologies, like the groundbreaking discovery of induced pluripotent stem cells and direct neuronal reprogramming, offering alternatives to the transplantation of fetal neurons, and both herald great expectations. For these to become reality, neuronal circuitry analysis is key now. As our understanding of neuronal circuits increases, neuronal replacement therapy should fulfill those prerequisites in network structure and function, in brain-wide input and output. Now is the time to incorporate neural circuitry research into regenerative medicine if we ever want to truly repair brain injury.
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Affiliation(s)
- Sofia Grade
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Magdalena Götz
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, 85764 Neuherberg, Germany
- SYNERGY, Excellence Cluster of Systems Neurology, Biomedical Center, Ludwig-Maximilians University Munich, 82152 Planegg-Martinsried, Germany
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