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Lüningschrör P, Andreska T, Veh A, Wolf D, Giridhar NJ, Moradi M, Denzel A, Sendtner M. Calnexin controls TrkB cell surface transport and ER-phagy in mouse cerebral cortex development. Dev Cell 2023; 58:1733-1747.e6. [PMID: 37506696 DOI: 10.1016/j.devcel.2023.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 05/23/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023]
Abstract
Transactivation of Tropomyosin receptor kinase B (TrkB) by EGF leads to cell surface transport of TrkB, promoting its signaling responsiveness to brain-derived neurotrophic factor (BDNF), a critical process for proper cortical plate development. However, the mechanisms that regulate the transport of TrkB to the cell surface are not fully understood. Here, we identified Calnexin as a regulator for targeting TrkB either to the cell surface or toward autophagosomal processing. Calnexin-deficient mouse embryos show impaired cortical plate formation and elevated levels of transactivated TrkB. In Calnexin-depleted mouse neuronal precursor cells, we detected an impaired cell surface transport of TrkB in response to EGF and an impaired delivery to autophagosomes. Mechanistically, we show that Calnexin facilitates the interaction of TrkB with the ER-phagy receptor Fam134b, thereby targeting TrkB to ER-phagy. This mechanism appears as a critical process for fine-tuning the sensitivity of neurons to BDNF.
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Affiliation(s)
- Patrick Lüningschrör
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Thomas Andreska
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Alexander Veh
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Daniel Wolf
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Neha Jadhav Giridhar
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Angela Denzel
- Imperial Cancer Research Fund now Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany.
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Massih B, Veh A, Schenke M, Mungwa S, Seeger B, Selvaraj BT, Chandran S, Reinhardt P, Sterneckert J, Hermann A, Sendtner M, Lüningschrör P. A 3D cell culture system for bioengineering human neuromuscular junctions to model ALS. Front Cell Dev Biol 2023; 11:996952. [PMID: 36866276 PMCID: PMC9973451 DOI: 10.3389/fcell.2023.996952] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 01/16/2023] [Indexed: 02/16/2023] Open
Abstract
The signals that coordinate and control movement in vertebrates are transmitted from motoneurons (MNs) to their target muscle cells at neuromuscular junctions (NMJs). Human NMJs display unique structural and physiological features, which make them vulnerable to pathological processes. NMJs are an early target in the pathology of motoneuron diseases (MND). Synaptic dysfunction and synapse elimination precede MN loss suggesting that the NMJ is the starting point of the pathophysiological cascade leading to MN death. Therefore, the study of human MNs in health and disease requires cell culture systems that enable the connection to their target muscle cells for NMJ formation. Here, we present a human neuromuscular co-culture system consisting of induced pluripotent stem cell (iPSC)-derived MNs and 3D skeletal muscle tissue derived from myoblasts. We used self-microfabricated silicone dishes combined with Velcro hooks to support the formation of 3D muscle tissue in a defined extracellular matrix, which enhances NMJ function and maturity. Using a combination of immunohistochemistry, calcium imaging, and pharmacological stimulations, we characterized and confirmed the function of the 3D muscle tissue and the 3D neuromuscular co-cultures. Finally, we applied this system as an in vitro model to study the pathophysiology of Amyotrophic Lateral Sclerosis (ALS) and found a decrease in neuromuscular coupling and muscle contraction in co-cultures with MNs harboring ALS-linked SOD1 mutation. In summary, the human 3D neuromuscular cell culture system presented here recapitulates aspects of human physiology in a controlled in vitro setting and is suitable for modeling of MND.
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Affiliation(s)
- Bita Massih
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Alexander Veh
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Maren Schenke
- Institute for Food Quality and Safety, Research Group Food Toxicology and Alternative/Complementary Methods to Animal Experiments, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Simon Mungwa
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Bettina Seeger
- Institute for Food Quality and Safety, Research Group Food Toxicology and Alternative/Complementary Methods to Animal Experiments, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Bhuvaneish T. Selvaraj
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh, United Kingdom
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, United Kingdom
| | - Siddharthan Chandran
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- UK Dementia Research Institute at University of Edinburgh, University of Edinburgh, Edinburgh, United Kingdom
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter Reinhardt
- Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Jared Sterneckert
- Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
- Medical Faculty Carl Gustav Carus of TU Dresden, Dresden, Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section “Albrecht-Kossel”, Department of Neurology, University Medical Center Rostock, Rostock, Germany
- Center for Transdisciplinary Neurosciences Rostock, University Medical Center Rostock, Rostock, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Rostock/Greifswald, Rostock, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Patrick Lüningschrör
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
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Müller H, Veh A, Grebe M, Grebe S. Value of thyroid hormone determination. BRATISL MED J 1989; 90:551-9. [PMID: 2605527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Free thyroid hormone assays have broadened the repertoire in thyroid diagnosis. At elevated binding protein levels they provide more reliable information on the metabolic state than do total hormone determinations; yet under estrogen contraception free T4 may yield test specifically falsely too high data. As a rule, there is accordance between free hormone concentrations and the indices, being equivalent in establishing the free thyroid hormone fraction. In this light the Thyroid Section of the German Endocrinologic Society recommended in 1986 to consider determinations of free or total hormone concentrations with calculation of the indices as being of equal value. In borderline situations the TRH test, the hypersensitivity TSH assay as well as checkups establishing the course of development of the disorder are substantiated.
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