Publications

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28 Publications visible to you, out of a total of 28

Abstract (Expand)

Oxytocin-expressing paraventricular hypothalamic neurons (PVN<sup>OT</sup> neurons) integrate afferent signals from the gut, including cholecystokinin (CCK), to adjust whole-body energy homeostasis. However, the molecular underpinnings by which PVN<sup>OT</sup> neurons orchestrate gut-to-brain feeding control remain unclear. Here, we show that mice undergoing selective ablation of PVN<sup>OT</sup> neurons fail to reduce food intake in response to CCK and develop hyperphagic obesity on a chow diet. Notably, exposing wild-type mice to a high-fat/high-sugar (HFHS) diet recapitulates this insensitivity toward CCK, which is linked to diet-induced transcriptional and electrophysiological aberrations specifically in PVN<sup>OT</sup> neurons. Restoring OT pathways in diet-induced obese (DIO) mice via chemogenetics or polypharmacology sufficiently re-establishes CCK's anorexigenic effects. Last, by single-cell profiling, we identify a specialized PVN<sup>OT</sup> neuronal subpopulation with increased κ-opioid signaling under an HFHS diet, which restrains their CCK-evoked activation. In sum, we document a (patho)mechanism by which PVN<sup>OT</sup> signaling uncouples a gut-brain satiation pathway under obesogenic conditions.

Authors: Tim Gruber, Franziska Lechner, Cahuê Murat, Raian E Contreras, Eva Sanchez-Quant, Viktorian Miok, Konstantinos Makris, Ophélia Le Thuc, Ismael González-García, Elena García-Clave, Ferdinand Althammer, Quirin Krabichler, Lisa M DeCamp, Russell G Jones, Dominik Lutter, Rhiannan H Williams, Paul T Pfluger, Timo D Müller, Stephen C Woods, John Andrew Pospisilik, Celia P Martinez-Jimenez, Matthias H Tschöp, Valery Grinevich, Cristina Garcia-Caceres

Date Published: 31st Oct 2023

Publication Type: Journal

Abstract (Expand)

Axon degeneration and functional decline in myelin diseases are often attributed to loss of myelin but their relation is not fully understood. Perturbed myelinating glia can instigate chronic neuroinflammation and contribute to demyelination and axonal damage. Here we study mice with distinct defects in the proteolipid protein 1 gene that develop axonal damage which is driven by cytotoxic T cells targeting myelinating oligodendrocytes. We show that persistent ensheathment with perturbed myelin poses a risk for axon degeneration, neuron loss, and behavioral decline. We demonstrate that CD8(+) T cell-driven axonal damage is less likely to progress towards degeneration when axons are efficiently demyelinated by activated microglia. Mechanistically, we show that cytotoxic T cell effector molecules induce cytoskeletal alterations within myelinating glia and aberrant actomyosin constriction of axons at paranodal domains. Our study identifies detrimental axon-glia-immune interactions which promote neurodegeneration and possible therapeutic targets for disorders associated with myelin defects and neuroinflammation.

Authors: J. Groh, T. Abdelwahab, Y. Kattimani, M. Horner, S. Loserth, V. Gudi, R. Adalbert, F. Imdahl, A. E. Saliba, M. Coleman, M. Stangel, M. Simons, R. Martini

Date Published: 30th Oct 2023

Publication Type: Journal

Abstract (Expand)

Multiple sclerosis (MS) involves the infiltration of autoreactive T cells into the CNS, yet we lack a comprehensive understanding of the signaling pathways that regulate this process. Here, we conducted a genome-wide in vivo CRISPR screen in a rat MS model and identified 5 essential brakes and 18 essential facilitators of T cell migration to the CNS. While the transcription factor ETS1 limits entry to the CNS by controlling T cell responsiveness, three functional modules, centered around the adhesion molecule alpha4-integrin, the chemokine receptor CXCR3 and the GRK2 kinase, are required for CNS migration of autoreactive CD4(+) T cells. Single-cell analysis of T cells from individuals with MS confirmed that the expression of these essential regulators correlates with the propensity of CD4(+) T cells to reach the CNS. Our data thus reveal key regulators of the fundamental step in the induction of MS lesions.

Authors: A. Kendirli, C. de la Rosa, K. F. Lammle, K. Eglseer, I. J. Bauer, V. Kavaka, S. Winklmeier, L. Zhuo, C. Wichmann, L. A. Gerdes, T. Kumpfel, K. Dornmair, E. Beltran, M. Kerschensteiner, N. Kawakami

Date Published: 4th Oct 2023

Publication Type: Journal

Abstract (Expand)

The bone marrow in the skull is important for shaping immune responses in the brain and meninges, but its molecular makeup among bones and relevance in human diseases remain unclear. Here, we show that the mouse skull has the most distinct transcriptomic profile compared with other bones in states of health and injury, characterized by a late-stage neutrophil phenotype. In humans, proteome analysis reveals that the skull marrow is the most distinct, with differentially expressed neutrophil-related pathways and a unique synaptic protein signature. 3D imaging demonstrates the structural and cellular details of human skull-meninges connections (SMCs) compared with veins. Last, using translocator protein positron emission tomography (TSPO-PET) imaging, we show that the skull bone marrow reflects inflammatory brain responses with a disease-specific spatial distribution in patients with various neurological disorders. The unique molecular profile and anatomical and functional connections of the skull show its potential as a site for diagnosing, monitoring, and treating brain diseases.

Authors: Zeynep Ilgin Kolabas, Louis B Kuemmerle, Robert Perneczky, Benjamin Förstera, Selin Ulukaya, Mayar Ali, Saketh Kapoor, Laura M Bartos, Maren Büttner, Ozum Sehnaz Caliskan, Zhouyi Rong, Hongcheng Mai, Luciano Höher, Denise Jeridi, Muge Molbay, Igor Khalin, Ioannis K Deligiannis, Moritz Negwer, Kenny Roberts, Alba Simats, Olga Carofiglio, Mihail I Todorov, Izabela Horvath, Furkan Ozturk, Selina Hummel, Gloria Biechele, Artem Zatcepin, Marcus Unterrainer, Johannes Gnörich, Jay Roodselaar, Joshua Shrouder, Pardis Khosravani, Benjamin Tast, Lisa Richter, Laura Díaz-Marugán, Doris Kaltenecker, Laurin Lux, Ying Chen, Shan Zhao, Boris-Stephan Rauchmann, Michael Sterr, Ines Kunze, Karen Stanic, Vanessa W Y Kan, Simon Besson-Girard, Sabrina Katzdobler, Carla Palleis, Julia Schädler, Johannes C Paetzold, Sabine Liebscher, Anja E Hauser, Özgün Gökçe, Heiko Lickert, Hanno Steinke, Corinne Benakis, Christian Braun, Celia P Martinez-Jimenez, Katharina Buerger, Nathalie L Albert, Günter Höglinger, Johannes Levin, Christian Haass, Anna Kopczak, Martin Dichgans, Joachim Havla, Tania Kümpfel, Martin Kerschensteiner, Martina Schifferer, Mikael Simons, Arthur Liesz, Natalie Krahmer, Omer A Bayraktar, Nicolai Franzmeier, Nikolaus Plesnila, Suheda Erener, Victor G Puelles, Claire Delbridge, Harsharan Singh Bhatia, Farida Hellal, Markus Elsner, Ingo Bechmann, Benjamin Ondruschka, Matthias Brendel, Fabian J Theis, Ali Ertürk

Date Published: 17th Aug 2023

Publication Type: Journal

Abstract (Expand)

Understanding the complexity of cellular function within a tissue necessitates the combination of multiple phenotypic readouts. Here, we developed a method that links spatially-resolved gene expression of single cells with their ultrastructural morphology by integrating multiplexed error-robust fluorescence in situ hybridization (MERFISH) and large area volume electron microscopy (EM) on adjacent tissue sections. Using this method, we characterized in situ ultrastructural and transcriptional responses of glial cells and infiltrating T-cells after demyelinating brain injury in male mice. We identified a population of lipid-loaded "foamy" microglia located in the center of remyelinating lesion, as well as rare interferon-responsive microglia, oligodendrocytes, and astrocytes that co-localized with T-cells. We validated our findings using immunocytochemistry and lipid staining-coupled single-cell RNA sequencing. Finally, by integrating these datasets, we detected correlations between full-transcriptome gene expression and ultrastructural features of microglia. Our results offer an integrative view of the spatial, ultrastructural, and transcriptional reorganization of single cells after demyelinating brain injury.

Authors: P. Androvic, M. Schifferer, K. Perez Anderson, L. Cantuti-Castelvetri, H. Jiang, H. Ji, L. Liu, G. Gouna, S. A. Berghoff, S. Besson-Girard, J. Knoferle, M. Simons, O. Gokce

Date Published: 11th Jul 2023

Publication Type: Journal

Abstract (Expand)

Neuroinflammation after stroke is characterized by the activation of resident microglia and the invasion of circulating leukocytes into the brain. Although lymphocytes infiltrate the brain in small number, they have been consistently demonstrated to be the most potent leukocyte subpopulation contributing to secondary inflammatory brain injury. However, the exact mechanism of how this minimal number of lymphocytes can profoundly affect stroke outcome is still largely elusive. Here, using a mouse model for ischemic stroke, we demonstrated that early activation of microglia in response to stroke is differentially regulated by distinct T cell subpopulations - with T(H1) cells inducing a type I INF signaling in microglia and regulatory T cells (T(REG)) cells promoting microglial genes associated with chemotaxis. Acute treatment with engineered T cells overexpressing IL-10 administered into the cisterna magna after stroke induces a switch of microglial gene expression to a profile associated with pro-regenerative functions. Whereas microglia polarization by T cell subsets did not affect the acute development of the infarct volume, these findings substantiate the role of T cells in stroke by polarizing the microglial phenotype. Targeting T cell-microglia interactions can have direct translational relevance for further development of immune-targeted therapies for stroke and other neuroinflammatory conditions.

Authors: C. Benakis, A. Simats, S. Tritschler, S. Heindl, S. Besson-Girard, G. Llovera, K. Pinkham, A. Kolz, A. Ricci, F. J. Theis, S. Bittner, O. Gokce, A. Peters, A. Liesz

Date Published: 13th Dec 2022

Publication Type: Journal

Abstract (Expand)

A hallmark of nervous system aging is a decline of white matter volume and function, but the underlying mechanisms leading to white matter pathology are unknown. In the present study, we found age-related alterations of oligodendrocyte cell state with a reduction in total oligodendrocyte density in aging murine white matter. Using single-cell RNA-sequencing, we identified interferon (IFN)-responsive oligodendrocytes, which localize in proximity to CD8(+) T cells in aging white matter. Absence of functional lymphocytes decreased the number of IFN-responsive oligodendrocytes and rescued oligodendrocyte loss, whereas T-cell checkpoint inhibition worsened the aging response. In addition, we identified a subpopulation of lymphocyte-dependent, IFN-responsive microglia in the vicinity of the CD8(+) T cells in aging white matter. In summary, we provide evidence that CD8(+) T-cell-induced, IFN-responsive oligodendrocytes and microglia are important modifiers of white matter aging.

Authors: T. Kaya, N. Mattugini, L. Liu, H. Ji, L. Cantuti-Castelvetri, J. Wu, M. Schifferer, J. Groh, R. Martini, S. Besson-Girard, S. Kaji, A. Liesz, O. Gokce, M. Simons

Date Published: 26th Oct 2022

Publication Type: Journal

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