Filter and export

Publications

What is a Publication?
39 Publications visible to you, out of a total of 39
Rational correction of pathogenic conformational defects in HTRA1.

Abstract (Expand)

Loss-of-function mutations in the homotrimeric serine protease HTRA1 cause cerebral vasculopathy. Here, we establish independent approaches to achieve the functional correction of trimer assembly … defects. Focusing on the prototypical R274Q mutation, we identify an HTRA1 variant that promotes trimer formation thus restoring enzymatic activity in vitro. Genetic experiments in Htra1<sup>R274Q</sup> mice further demonstrate that expression of this protein-based corrector in trans is sufficient to stabilize HtrA1-R274Q and restore the proteomic signature of the brain vasculature. An alternative approach employs supramolecular chemical ligands that shift the monomer-trimer equilibrium towards proteolytically active trimers. Moreover, we identify a peptidic ligand that activates HTRA1 monomers. Our findings open perspectives for tailored protein repair strategies.

Authors: Nathalie Beaufort, Linda Ingendahl, Melisa Merdanovic, Andree Schmidt, David Podlesainski, Tim Richter, Thorben Neumann, Michael Kuszner, Ingrid R Vetter, Patricia Stege, Steven G Burston, Anto Filipovic, Yasser B Ruiz-Blanco, Kenny Bravo-Rodriguez, Joel Mieres-Perez, Christine Beuck, Stephan Uebel, Monika Zobawa, Jasmin Schillinger, Rainer Malik, Katalin Todorov-Völgyi, Juliana Rey, Annabell Roberti, Birte Hagemeier, Benedikt Wefers, Stephan A Müller, Wolfgang Wurst, Elsa Sanchez-Garcia, Alexander Zimmermann, Xiao-Yu Hu, Tim Clausen, Robert Huber, Stefan F Lichtenthaler, Carsten Schmuck, Michael Giese, Markus Kaiser, Michael Ehrmann, Martin Dichgans

Date Published: 16th Jul 2024

Publication Type: Journal

Multiomic ALS signatures highlight subclusters and sex differences suggesting the MAPK pathway as therapeutic target.

Abstract (Expand)

Amyotrophic lateral sclerosis (ALS) is a debilitating motor neuron disease and lacks effective disease-modifying treatments. This study utilizes a comprehensive multiomic approach to investigate the … early and sex-specific molecular mechanisms underlying ALS. By analyzing the prefrontal cortex of 51 patients with sporadic ALS and 50 control subjects, alongside four transgenic mouse models (C9orf72-, SOD1-, TDP-43-, and FUS-ALS), we have uncovered significant molecular alterations associated with the disease. Here, we show that males exhibit more pronounced changes in molecular pathways compared to females. Our integrated analysis of transcriptomes, (phospho)proteomes, and miRNAomes also identified distinct ALS subclusters in humans, characterized by variations in immune response, extracellular matrix composition, mitochondrial function, and RNA processing. The molecular signatures of human subclusters were reflected in specific mouse models. Our study highlighted the mitogen-activated protein kinase (MAPK) pathway as an early disease mechanism. We further demonstrate that trametinib, a MAPK inhibitor, has potential therapeutic benefits in vitro and in vivo, particularly in females, suggesting a direction for developing targeted ALS treatments.

Authors: Lucas Caldi Gomes, Sonja Hänzelmann, Fabian Hausmann, Robin Khatri, Sergio Oller, Mojan Parvaz, Laura Tzeplaeff, Laura Pasetto, Marie Gebelin, Melanie Ebbing, Constantin Holzapfel, Stefano Fabrizio Columbro, Serena Scozzari, Johanna Knöferle, Isabell Cordts, Antonia F Demleitner, Marcus Deschauer, Claudia Dufke, Marc Sturm, Qihui Zhou, Pavol Zelina, Emma Sudria-Lopez, Tobias B Haack, Sebastian Streb, Magdalena Kuzma-Kozakiewicz, Dieter Edbauer, R Jeroen Pasterkamp, Endre Laczko, Hubert Rehrauer, Ralph Schlapbach, Christine Carapito, Valentina Bonetto, Stefan Bonn, Paul Lingor

Date Published: 1st Jul 2024

Publication Type: Journal

T cell-mediated microglial activation triggers myelin pathology in a mouse model of amyloidosis.

Abstract (Expand)

Age-related myelin damage induces inflammatory responses, yet its involvement in Alzheimer's disease remains uncertain, despite age being a major risk factor. Using a mouse model of Alzheimer's … disease, we found that amyloidosis itself triggers age-related oligodendrocyte and myelin damage. Mechanistically, CD8<sup>+</sup> T cells promote the progressive accumulation of abnormally interferon-activated microglia that display myelin-damaging activity. Thus, our data suggest that immune responses against myelinating oligodendrocytes may contribute to neurodegenerative diseases with amyloidosis.

Authors: Shreeya Kedia, Hao Ji, Ruoqing Feng, Peter Androvic, Lena Spieth, Lu Liu, Jonas Franz, Hanna Zdiarstek, Katrin Perez Anderson, Cem Kaboglu, Qian Liu, Nicola Mattugini, Fatma Cherif, Danilo Prtvar, Ludovico Cantuti-Castelvetri, Arthur Liesz, Martina Schifferer, Christine Stadelmann, Sabina Tahirovic, Özgün Gökçe, Mikael Simons

Date Published: 27th Jun 2024

Publication Type: Journal

Peripheral expression of brain-penetrant progranulin rescues pathologies in mouse models of frontotemporal lobar degeneration.

Abstract (Expand)

Progranulin (PGRN) haploinsufficiency is a major risk factor for frontotemporal lobar degeneration with TAR DNA-binding protein 43 (TDP-43) pathology (FTLD-<i>GRN</i>). Multiple therapeutic … strategies are in clinical development to restore PGRN in the CNS, including gene therapy. However, a limitation of current gene therapy approaches aimed to alleviate FTLD-associated pathologies may be their inefficient brain exposure and biodistribution. We therefore developed an adeno-associated virus (AAV) targeting the liver (L) to achieve sustained peripheral expression of a transferrin receptor (TfR) binding, brain-penetrant (b) PGRN variant [AAV(L):bPGRN] in two mouse models of FTLD-<i>GRN</i>, namely, <i>Grn</i> knockout and <i>GrnxTmem106b</i> double knockout mice. This therapeutic strategy avoids potential safety and biodistribution issues of CNS-administered AAVs and maintains sustained concentrations of PGRN in the brain after a single dose. AAV(L):bPGRN treatment reduced several FTLD-<i>GRN</i>-associated pathologies including severe motor function deficits, aberrant TDP-43 phosphorylation, dysfunctional protein degradation, lipid metabolism, gliosis, and neurodegeneration in the brain. The potential translatability of our findings was tested in an in vitro model using cocultured human induced pluripotent stem cell (hiPSC)-derived microglia lacking PGRN and TMEM106B and wild-type hiPSC-derived neurons. As in mice, aberrant TDP-43, lysosomal dysfunction, and neuronal loss were ameliorated after treatment with exogenous TfR-binding protein transport vehicle fused to PGRN (PTV:PGRN). Together, our studies suggest that peripherally administered brain-penetrant PGRN replacement strategies ameliorate FTLD-<i>GRN</i> relevant phenotypes including TDP-43 pathology, neurodegeneration, and behavioral deficits. Our data provide preclinical proof of concept for the use of this AAV platform for treatment of FTLD-<i>GRN</i> and potentially other CNS disorders.

Authors: Marvin Reich, Matthew J Simon, Beate Polke, Iñaki Paris, Georg Werner, Christian Schrader, Lena Spieth, Sonnet S Davis, Sophie Robinson, Gabrielly Lunkes de Melo, Lennart Schlaphoff, Katrin Buschmann, Stefan Berghoff, Todd Logan, Brigitte Nuscher, Lis de Weerd, Dieter Edbauer, Mikael Simons, Jung H Suh, Thomas Sandmann, Mihalis S Kariolis, Sarah L DeVos, Joseph W Lewcock, Dominik Paquet, Anja Capell, Gilbert Di Paolo, Christian Haass

Date Published: 5th Jun 2024

Publication Type: Journal

Cellular depletion of major cathepsin proteases reveals their concerted activities for lysosomal proteolysis.

Abstract (Expand)

Proteins delivered by endocytosis or autophagy to lysosomes are degraded by exo- and endoproteases. In humans 15 lysosomal cathepsins (CTS) act as important physiological regulators. The cysteine … proteases CTSB and CTSL and the aspartic protease CTSD are the most abundant and functional important lysosomal proteinases. Whereas their general functions in proteolysis in the lysosome, their individual substrate, cleavage specificity, and their possible sequential action on substrate proteins have been previously studied, their functional redundancy is still poorly understood. To address a possible common role of highly expressed and functional important CTS proteases, we generated CTSB-, CTSD-, CTSL-, and CTSBDL-triple deficient (KO) human neuroblastoma-derived SH-SY5Y cells and CTSB-, CTSD-, CTSL-, CTSZ and CTSBDLZ-quadruple deficient (KO) HeLa cells. These cells with a combined cathepsin deficiency exhibited enlarged lysosomes and accumulated lipofuscin-like storage material. The lack of the three (SH-SY5Y) or four (HeLa) major CTSs caused an impaired autophagic flux and reduced degradation of endocytosed albumin. Proteome analyses of parental and CTS-depleted cells revealed an enrichment of cleaved peptides, lysosome/autophagy-associated proteins, and potentially endocytosed membrane proteins like the amyloid precursor protein (APP), which can be subject to endocytic degradation. Amino- and carboxyterminal APP fragments accumulated in the multiple CTS-deficient cells, suggesting that multiple CTS-mediated cleavage events regularly process APP. In summary, our analyses support the idea that different lysosomal cathepsins act in concert, have at least partially and functionally redundant substrates, regulate protein degradation in autophagy, and control cellular proteostasis, as exemplified by their involvement in the degradation of APP fragments.

Authors: Lisa Gallwitz, Florian Bleibaum, Matthias Voss, Michaela Schweizer, Katharina Spengler, Dominic Winter, Frederic Zöphel, Stephan Müller, Stefan Lichtenthaler, Markus Damme, Paul Saftig

Date Published: 22nd May 2024

Publication Type: Journal

Lysosomal damage sensing and lysophagy initiation by SPG20-ITCH.

Abstract (Expand)

Cells respond to lysosomal membrane permeabilization by membrane repair or selective macroautophagy of damaged lysosomes, termed lysophagy, but it is not fully understood how this decision is made. … Here, we uncover a pathway in human cells that detects lipid bilayer perturbations in the limiting membrane of compromised lysosomes, which fail to be repaired, and then initiates ubiquitin-triggered lysophagy. We find that SPG20 binds the repair factor IST1 on damaged lysosomes and, importantly, integrates that with the detection of damage-associated lipid-packing defects of the lysosomal membrane. Detection occurs via sensory amphipathic helices in SPG20 before rupture of the membrane. If lipid-packing defects are extensive, such as during lipid peroxidation, SPG20 recruits and activates ITCH, which marks the damaged lysosome with lysine-63-linked ubiquitin chains to initiate lysophagy and thus triages the lysosome for destruction. With SPG20 being linked to neurodegeneration, these findings highlight the relevance of a coordinated lysosomal damage response for cellular homeostasis.

Authors: Pinki Gahlot, Bojana Kravic, Giulia Rota, Johannes van den Boom, Sophie Levantovsky, Nina Schulze, Elena Maspero, Simona Polo, Christian Behrends, Hemmo Meyer

Date Published: 18th Apr 2024

Publication Type: Journal

Shared inflammatory glial cell signature after stab wound injury, revealed by spatial, temporal, and cell-type-specific profiling of the murine cerebral cortex.

Abstract (Expand)

Traumatic brain injury leads to a highly orchestrated immune- and glial cell response partially responsible for long-lasting disability and the development of secondary neurodegenerative diseases. A … holistic understanding of the mechanisms controlling the responses of specific cell types and their crosstalk is required to develop an efficient strategy for better regeneration. Here, we combine spatial and single-cell transcriptomics to chart the transcriptomic signature of the injured male murine cerebral cortex, and identify specific states of different glial cells contributing to this signature. Interestingly, distinct glial cells share a large fraction of injury-regulated genes, including inflammatory programs downstream of the innate immune-associated pathways Cxcr3 and Tlr1/2. Systemic manipulation of these pathways decreases the reactivity state of glial cells associated with poor regeneration. The functional relevance of the discovered shared signature of glial cells highlights the importance of our resource enabling comprehensive analysis of early events after brain injury.

Authors: Christina Koupourtidou, Veronika Schwarz, Hananeh Aliee, Simon Frerich, Judith Fischer-Sternjak, Riccardo Bocchi, Tatiana Simon-Ebert, Xianshu Bai, Swetlana Sirko, Frank Kirchhoff, Martin Dichgans, Magdalena Götz, Fabian J Theis, Jovica Ninkovic

Date Published: 3rd Apr 2024

Publication Type: Journal

Powered by
 (v.1.15.0)
About FAIRDOM | About SyNergy (Munich Cluster for Systems Neurology) | Funding and Programmes | Credits
Copyright © 2008 - 2024 The University of Manchester and HITS gGmbH