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Ransdell JL, Carrasquillo Y, Bosch MK, Mellor RL, Ornitz DM, Nerbonne JM. Loss of Intracellular Fibroblast Growth Factor 14 (iFGF14) Increases the Excitability of Mature Hippocampal and Cortical Pyramidal Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.04.592532. [PMID: 38746081 PMCID: PMC11092765 DOI: 10.1101/2024.05.04.592532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Mutations in FGF14 , which encodes intracellular fibroblast growth factor 14 (iFGF14), have been linked to spinocerebellar ataxia type 27 (SCA27), a multisystem disorder associated with progressive deficits in motor coordination and cognitive function. Mice ( Fgf14 -/- ) lacking iFGF14 display similar phenotypes, and we have previously shown that the deficits in motor coordination reflect reduced excitability of cerebellar Purkinje neurons, owing to the loss of iFGF14-mediated regulation of the voltage-dependence of inactivation of the fast transient component of the voltage-gated Na + (Nav) current, I NaT . Here, we present the results of experiments designed to test the hypothesis that loss of iFGF14 also attenuates the intrinsic excitability of mature hippocampal and cortical pyramidal neurons. Current-clamp recordings from adult mouse hippocampal CA1 pyramidal neurons in acute in vitro slices, however, revealed that repetitive firing rates were higher in Fgf14 -/- , than in wild type (WT), cells. In addition, the waveforms of individual action potentials were altered in Fgf14 -/- hippocampal CA1 pyramidal neurons, and the loss of iFGF14 reduced the time delay between the initiation of axonal and somal action potentials. Voltage-clamp recordings revealed that the loss of iFGF14 altered the voltage-dependence of activation, but not inactivation, of I NaT in CA1 pyramidal neurons. Similar effects of the loss of iFGF14 on firing properties were evident in current-clamp recordings from layer 5 visual cortical pyramidal neurons. Additional experiments demonstrated that the loss of iFGF14 does not alter the distribution of anti-Nav1.6 or anti-ankyrin G immunofluorescence labeling intensity along the axon initial segments (AIS) of mature hippocampal CA1 or layer 5 visual cortical pyramidal neurons in situ . Taken together, the results demonstrate that, in contrast with results reported for neonatal (rat) hippocampal pyramidal neurons in dissociated cell culture, the loss of iFGF14 does not disrupt AIS architecture or Nav1.6 localization/distribution along the AIS of mature hippocampal (or cortical) pyramidal neurons in situ .
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Gędaj A, Chorążewska A, Ciura K, Karelus R, Żukowska D, Biaduń M, Kalka M, Zakrzewska M, Porębska N, Opaliński Ł. The intracellular interplay between galectin-1 and FGF12 in the assembly of ribosome biogenesis complex. Cell Commun Signal 2024; 22:175. [PMID: 38468333 PMCID: PMC10926643 DOI: 10.1186/s12964-024-01558-1] [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: 01/10/2024] [Accepted: 03/04/2024] [Indexed: 03/13/2024] Open
Abstract
Galectins constitute a class of lectins that specifically interact with β-galactoside sugars in glycoconjugates and are implicated in diverse cellular processes, including transport, autophagy or signaling. Since most of the activity of galectins depends on their ability to bind sugar chains, galectins exert their functions mainly in the extracellular space or at the cell surface, which are microenvironments highly enriched in glycoconjugates. Galectins are also abundant inside cells, but their specific intracellular functions are largely unknown. Here we report that galectin-1, -3, -7 and -8 directly interact with the proteinaceous core of fibroblast growth factor 12 (FGF12) in the cytosol and in nucleus. We demonstrate that binding of galectin-1 to FGF12 in the cytosol blocks FGF12 secretion. Furthermore, we show that intracellular galectin-1 affects the assembly of FGF12-containing nuclear/nucleolar ribosome biogenesis complexes consisting of NOLC1 and TCOF1. Our data provide a new link between galectins and FGF proteins, revealing an unexpected glycosylation-independent intracellular interplay between these groups of proteins.
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Affiliation(s)
- Aleksandra Gędaj
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Aleksandra Chorążewska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Krzysztof Ciura
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Radosław Karelus
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Dominika Żukowska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Martyna Biaduń
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Marta Kalka
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Małgorzata Zakrzewska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Natalia Porębska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Łukasz Opaliński
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland.
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Libé-Philippot B, Lejeune A, Wierda K, Louros N, Erkol E, Vlaeminck I, Beckers S, Gaspariunaite V, Bilheu A, Konstantoulea K, Nyitrai H, De Vleeschouwer M, Vennekens KM, Vidal N, Bird TW, Soto DC, Jaspers T, Dewilde M, Dennis MY, Rousseau F, Comoletti D, Schymkowitz J, Theys T, de Wit J, Vanderhaeghen P. LRRC37B is a human modifier of voltage-gated sodium channels and axon excitability in cortical neurons. Cell 2023; 186:5766-5783.e25. [PMID: 38134874 PMCID: PMC10754148 DOI: 10.1016/j.cell.2023.11.028] [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: 12/02/2022] [Revised: 06/28/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023]
Abstract
The enhanced cognitive abilities characterizing the human species result from specialized features of neurons and circuits. Here, we report that the hominid-specific gene LRRC37B encodes a receptor expressed in human cortical pyramidal neurons (CPNs) and selectively localized to the axon initial segment (AIS), the subcellular compartment triggering action potentials. Ectopic expression of LRRC37B in mouse CPNs in vivo leads to reduced intrinsic excitability, a distinctive feature of some classes of human CPNs. Molecularly, LRRC37B binds to the secreted ligand FGF13A and to the voltage-gated sodium channel (Nav) β-subunit SCN1B. LRRC37B concentrates inhibitory effects of FGF13A on Nav channel function, thereby reducing excitability, specifically at the AIS level. Electrophysiological recordings in adult human cortical slices reveal lower neuronal excitability in human CPNs expressing LRRC37B. LRRC37B thus acts as a species-specific modifier of human neuron excitability, linking human genome and cell evolution, with important implications for human brain function and diseases.
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Affiliation(s)
- Baptiste Libé-Philippot
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Amélie Lejeune
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Keimpe Wierda
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Electrophysiology Unit, VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | - Nikolaos Louros
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Cellular and Molecular Medicine, KUL, 3000 Leuven, Belgium
| | - Emir Erkol
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Ine Vlaeminck
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Electrophysiology Unit, VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium
| | - Sofie Beckers
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Vaiva Gaspariunaite
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Angéline Bilheu
- Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), 1070 Brussels, Belgium
| | - Katerina Konstantoulea
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Cellular and Molecular Medicine, KUL, 3000 Leuven, Belgium
| | - Hajnalka Nyitrai
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Matthias De Vleeschouwer
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Cellular and Molecular Medicine, KUL, 3000 Leuven, Belgium
| | - Kristel M Vennekens
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Niels Vidal
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium
| | - Thomas W Bird
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Daniela C Soto
- Genome Center, MIND Institute, and Department of Biochemistry & Molecular Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Tom Jaspers
- Laboratory for Therapeutic and Diagnostic Antibodies, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Maarten Dewilde
- Laboratory for Therapeutic and Diagnostic Antibodies, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Megan Y Dennis
- Genome Center, MIND Institute, and Department of Biochemistry & Molecular Medicine, University of California, Davis, Davis, CA 95616, USA
| | - Frederic Rousseau
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Cellular and Molecular Medicine, KUL, 3000 Leuven, Belgium
| | - Davide Comoletti
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; Child Health Institute of New Jersey, Rutgers University, New Brunswick, NJ 08901, USA
| | - Joost Schymkowitz
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; Department of Cellular and Molecular Medicine, KUL, 3000 Leuven, Belgium
| | - Tom Theys
- KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium; Research Group Experimental Neurosurgery and Neuroanatomy, KUL, 3000 Leuven, Belgium
| | - Joris de Wit
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium.
| | - Pierre Vanderhaeghen
- VIB-KU Leuven Center for Brain & Disease Research, 3000 Leuven, Belgium; KUL, Department of Neurosciences, Leuven Brain Institute, 3000 Leuven, Belgium; Université Libre de Bruxelles (ULB), Institute for Interdisciplinary Research (IRIBHM), 1070 Brussels, Belgium.
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