1
|
Baltissen D, Bold CS, Rehra L, Banićević M, Fricke J, Just J, Ludewig S, Buchholz CJ, Korte M, Müller UC. APPsα rescues CDK5 and GSK3β dysregulation and restores normal spine density in Tau transgenic mice. Front Cell Neurosci 2023; 17:1106176. [PMID: 36779015 PMCID: PMC9909437 DOI: 10.3389/fncel.2023.1106176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/02/2023] [Indexed: 01/27/2023] Open
Abstract
The Tau protein can be phosphorylated by numerous kinases. In Alzheimer's disease (AD) hyperphosphorylated Tau species accumulate as neurofibrillary tangles that constitute a major hallmark of AD. AD is further characterized by extracellular Aβ plaques, derived from the β-amyloid precursor protein APP. Whereas Aβ is produced by amyloidogenic APP processing, APP processing along the competing non-amyloidogenic pathway results in the secretion of neurotrophic and synaptotrophic APPsα. Recently, we demonstrated that APPsα has therapeutic effects in transgenic AD model mice and rescues Aβ-dependent impairments. Here, we examined the potential of APPsα to regulate two major Tau kinases, GSK3β and CDK5 in THY-Tau22 mice, a widely used mouse model of tauopathy. Immunohistochemistry revealed a dramatic increase in pathologically phosphorylated (AT8 and AT180) or misfolded Tau species (MC1) in the hippocampus of THY-Tau22 mice between 3 and 12 months of age. Using a highly sensitive radioactive kinase assay with recombinant human Tau as a substrate and immunoblotting, we demonstrate an increase in GSK3β and CDK5 activity in the hippocampus of THY-Tau22 mice. Interestingly, AAV-mediated intracranial expression of APPsα in THY-Tau22 mice efficiently restored normal GSK3β and CDK5 activity. Western blot analysis revealed upregulation of the CDK5 regulatory proteins p35 and p25, indicating CDK5 hyperactivation in THY-Tau22 mice. Strikingly, AAV-APPsα rescued p25 upregulation to wild-type levels even at stages of advanced Tau pathology. Sarkosyl fractionation used to study the abundance of soluble and insoluble phospho-Tau species revealed increased soluble AT8-Tau and decreased insoluble AT100-Tau species upon AAV-APPsα injection. Moreover, AAV-APPsα reduced misfolded (MC1) Tau species, particularly in somatodendritic compartments of CA1 pyramidal neurons. Finally, we show that AAV-APPsα upregulated PSD95 expression and rescued deficits in spine density of THY-Tau22 mice. Together our findings suggest that APPsα holds therapeutic potential to mitigate Tau-induced pathology.
Collapse
Affiliation(s)
- Danny Baltissen
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Charlotte S. Bold
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Lena Rehra
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Marija Banićević
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Justus Fricke
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Jennifer Just
- Department of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
| | - Susann Ludewig
- Department of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany
| | - Christian J. Buchholz
- Department of Molecular Biotechnology and Gene Therapy, Paul-Ehrlich-Institut, Langen, Germany
| | - Martin Korte
- Department of Cellular Neurobiology, Zoological Institute, Technical University of Braunschweig, Braunschweig, Germany,Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, Germany
| | - Ulrike C. Müller
- Department of Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany,*Correspondence: Ulrike C. Müller,
| |
Collapse
|
2
|
Bold CS, Baltissen D, Ludewig S, Back MK, Just J, Kilian L, Erdinger S, Banicevic M, Rehra L, Almouhanna F, Nigri M, Wolfer DP, Spilger R, Rohr K, Kann O, Buchholz CJ, von Engelhardt J, Korte M, Müller UC. APPsα Rescues Tau-Induced Synaptic Pathology. J Neurosci 2022; 42:5782-5802. [PMID: 35667850 PMCID: PMC9302470 DOI: 10.1523/jneurosci.2200-21.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/06/2022] [Accepted: 05/22/2022] [Indexed: 01/22/2023] Open
Abstract
Alzheimer's disease (AD) is histopathologically characterized by Aβ plaques and the accumulation of hyperphosphorylated Tau species, the latter also constituting key hallmarks of primary tauopathies. Whereas Aβ is produced by amyloidogenic APP processing, APP processing along the competing nonamyloidogenic pathway results in the secretion of neurotrophic and synaptotrophic APPsα. Recently, we demonstrated that APPsα has therapeutic effects in transgenic AD model mice and rescues Aβ-dependent impairments. Here, we examined the potential of APPsα to mitigate Tau-induced synaptic deficits in P301S mice (both sexes), a widely used mouse model of tauopathy. Analysis of synaptic plasticity revealed an aberrantly increased LTP in P301S mice that could be normalized by acute application of nanomolar amounts of APPsα to hippocampal slices, indicating a homeostatic function of APPsα on a rapid time scale. Further, AAV-mediated in vivo expression of APPsα restored normal spine density of CA1 neurons even at stages of advanced Tau pathology not only in P301S mice, but also in independent THY-Tau22 mice. Strikingly, when searching for the mechanism underlying aberrantly increased LTP in P301S mice, we identified an early and progressive loss of major GABAergic interneuron subtypes in the hippocampus of P301S mice, which may lead to reduced GABAergic inhibition of principal cells. Interneuron loss was paralleled by deficits in nest building, an innate behavior highly sensitive to hippocampal impairments. Together, our findings indicate that APPsα has therapeutic potential for Tau-mediated synaptic dysfunction and suggest that loss of interneurons leads to disturbed neuronal circuits that compromise synaptic plasticity as well as behavior.SIGNIFICANCE STATEMENT Our findings indicate, for the first time, that APPsα has the potential to rescue Tau-induced spine loss and abnormal synaptic plasticity. Thus, APPsα might have therapeutic potential not only because of its synaptotrophic functions, but also its homeostatic capacity for neuronal network activity. Hence, APPsα is one of the few molecules which has proven therapeutic effects in mice, both for Aβ- and Tau-dependent synaptic impairments and might therefore have therapeutic potential for patients suffering from AD or primary tauopathies. Furthermore, we found in P301S mice a pronounced reduction of inhibitory interneurons as the earliest pathologic event preceding the accumulation of hyperphosphorylated Tau species. This loss of interneurons most likely disturbs neuronal circuits that are important for synaptic plasticity and behavior.
Collapse
Affiliation(s)
- Charlotte S Bold
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Danny Baltissen
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Susann Ludewig
- TU Braunschweig, Zoological Institute, Braunschweig, 38106, Germany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, 38124, Germany
| | - Michaela K Back
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Jennifer Just
- TU Braunschweig, Zoological Institute, Braunschweig, 38106, Germany
| | - Lara Kilian
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Susanne Erdinger
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Marija Banicevic
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Lena Rehra
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Fadi Almouhanna
- Institute of Physiology and Pathophysiology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | - Martina Nigri
- Institute of Anatomy, University of Zurich, Zurich, 8057, Switzerland
| | - David P Wolfer
- Institute of Anatomy, University of Zurich, Zurich, 8057, Switzerland
- Institute of Human Movement Sciences and Sport, ETH Zurich, Zurich, Switzerland
| | - Roman Spilger
- BioQuant Center, Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg and DKFZ, Heidelberg, 69120, Germany
| | - Karl Rohr
- BioQuant Center, Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg and DKFZ, Heidelberg, 69120, Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| | | | - Jakob von Engelhardt
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Martin Korte
- TU Braunschweig, Zoological Institute, Braunschweig, 38106, Germany
- Helmholtz Centre for Infection Research, Neuroinflammation and Neurodegeneration Group, Braunschweig, 38124, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht Karls Universität Heidelberg, Heidelberg, 69120, Germany
| |
Collapse
|