Publications

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52 Publications visible to you, out of a total of 52

Abstract (Expand)

Transplantation is a clinically relevant approach for brain repair, but much remains to be understood about influences of the disease environment on transplant connectivity. To explore the effect of amyloid pathology in Alzheimer's disease (AD) and aging, we examined graft connectivity using monosynaptic rabies virus tracing in APP/PS1 mice and in 16- to 18-month-old wild-type (WT) mice. Transplanted neurons differentiated within 4 weeks and integrated well into the host visual cortex, receiving input from the appropriate brain regions for this area. Unexpectedly, we found a prominent several-fold increase in local inputs, in both amyloid-loaded and aged environments. State-of-the-art deep proteome analysis using mass spectrometry highlights complement system activation as a common denominator of environments promoting excessive local input connectivity. These data therefore reveal the key role of the host pathology in shaping the input connectome, calling for caution in extrapolating results from one pathological condition to another.

Authors: Judith Thomas, Maria Fernanda Martinez-Reza, Manja Thorwirth, Yvette Zarb, Karl-Klaus Conzelmann, Stefanie M Hauck, Sofia Grade, Magdalena Götz

Date Published: 10th Jun 2022

Publication Type: Journal

Abstract (Expand)

Direct reprogramming based on genetic factors resembles a promising strategy to replace lost cells in degenerative diseases such as Parkinson's disease. For this, we developed a knock-in mouse line carrying a dual dCas9 transactivator system (dCAM) allowing the conditional in vivo activation of endogenous genes. To enable a translational application, we additionally established an AAV-based strategy carrying intein-split-dCas9 in combination with activators (AAV-dCAS). Both approaches were successful in reprogramming striatal astrocytes into induced GABAergic neurons confirmed by single-cell transcriptome analysis of reprogrammed neurons in vivo. These GABAergic neurons functionally integrate into striatal circuits, alleviating voluntary motor behavior aspects in a 6-OHDA Parkinson's disease model. Our results suggest a novel intervention strategy beyond the restoration of dopamine levels. Thus, the AAV-dCAS approach might enable an alternative route for clinical therapies of Parkinson's disease.

Authors: Jessica Giehrl-Schwab, Florian Giesert, Benedict Rauser, Chu Lan Lao, Sina Hembach, Sandrine Lefort, Ignacio L Ibarra, Christina Koupourtidou, Malte Daniel Luecken, Dong-Jiunn Jeffery Truong, Judith Fischer-Sternjak, Giacomo Masserdotti, Nilima Prakash, Jovica Ninkovic, Sabine M Hölter, Daniela M Vogt Weisenhorn, Fabian J Theis, Magdalena Götz, Wolfgang Wurst

Date Published: 9th May 2022

Publication Type: Journal

Abstract (Expand)

PTEN-induced kinase 1 (PINK1) is a short-lived protein required for the removal of damaged mitochondria through Parkin translocation and mitophagy. Because the short half-life of PINK1 limits its ability to be trafficked into neurites, local translation is required for this mitophagy pathway to be active far from the soma. The Pink1 transcript is associated and cotransported with neuronal mitochondria. In concert with translation, the mitochondrial outer membrane proteins synaptojanin 2 binding protein (SYNJ2BP) and synaptojanin 2 (SYNJ2) are required for tethering Pink1 mRNA to mitochondria via an RNA-binding domain in SYNJ2. This neuron-specific adaptation for the local translation of PINK1 provides distal mitochondria with a continuous supply of PINK1 for the activation of mitophagy.

Authors: Angelika B Harbauer, J Tabitha Hees, Simone Wanderoy, Inmaculada Segura, Whitney Gibbs, Yiming Cheng, Martha Ordonez, Zerong Cai, Romain Cartoni, Ghazaleh Ashrafi, Chen Wang, Fabiana Perocchi, Zhigang He, Thomas L Schwarz

Date Published: 4th May 2022

Publication Type: Journal

Abstract (Expand)

The oligodendrocyte progenitors (OPCs) are at the front of the glial reaction to the traumatic brain injury. However, regulatory pathways steering the OPC reaction as well as the role of reactive OPCs remain largely unknown. Here, we compared a long-lasting, exacerbated reaction of OPCs to the adult zebrafish brain injury with a timely restricted OPC activation to identify the specific molecular mechanisms regulating OPC reactivity and their contribution to regeneration. We demonstrated that the influx of the cerebrospinal fluid into the brain parenchyma after injury simultaneously activates the toll-like receptor 2 (Tlr2) and the chemokine receptor 3 (Cxcr3) innate immunity pathways, leading to increased OPC proliferation and thereby exacerbated glial reactivity. These pathways were critical for long-lasting OPC accumulation even after the ablation of microglia and infiltrating monocytes. Importantly, interference with the Tlr1/2 and Cxcr3 pathways after injury alleviated reactive gliosis, increased new neuron recruitment, and improved tissue restoration.

Authors: Rosario Sanchez-Gonzalez, Christina Koupourtidou, Tjasa Lepko, Alessandro Zambusi, Klara Tereza Novoselc, Tamara Durovic, Sven Aschenbroich, Veronika Schwarz, Christopher T Breunig, Hans Straka, Hagen B Huttner, Martin Irmler, Johannes Beckers, Wolfgang Wurst, Andreas Zwergal, Tamas Schauer, Tobias Straub, Tim Czopka, Dietrich Trümbach, Magdalena Götz, Stefan H Stricker, Jovica Ninkovic

Date Published: 2nd Feb 2022

Publication Type: Journal

Abstract (Expand)

Parkinson's disease (PD) is the second most common neurodegenerative disorder whose prevalence is rapidly increasing worldwide. The molecular mechanisms underpinning the pathophysiology of sporadic PD remain incompletely understood. Therefore, causative therapies are still elusive. To obtain a more integrative view of disease-mediated alterations, we investigated the molecular landscape of PD in human post-mortem midbrains, a region that is highly affected during the disease process.

Authors: Lucas Caldi Gomes, Ana Galhoz, Gaurav Jain, Anna-Elisa Roser, Fabian Maass, Eleonora Carboni, Elisabeth Barski, Christof Lenz, Katja Lohmann, Christine Klein, Mathias Bähr, André Fischer, Michael P Menden, Paul Lingor

Date Published: 28th Jan 2022

Publication Type: Journal

Abstract (Expand)

Astrocytes regulate brain-wide functions and also show region-specific differences, but little is known about how general and region-specific functions are aligned at the single-cell level. To explore this, we isolated adult mouse diencephalic astrocytes by ACSA-2-mediated magnetic-activated cell sorting (MACS). Single-cell RNA-seq revealed 7 gene expression clusters of astrocytes, with 4 forming a supercluster. Within the supercluster, cells differed by gene expression related to ion homeostasis or metabolism, with the former sharing gene expression with other regions and the latter being restricted to specific regions. All clusters showed expression of proliferation-related genes, and proliferation of diencephalic astrocytes was confirmed by immunostaining. Clonal analysis demonstrated low level of astrogenesis in the adult diencephalon, but not in cerebral cortex grey matter. This led to the identification of Smad4 as a key regulator of diencephalic astrocyte in vivo proliferation and in vitro neurosphere formation. Thus, astrocytes show diverse gene expression states related to distinct functions with some subsets being more widespread while others are more regionally restricted. However, all share low-level proliferation revealing the novel concept of adult astrogenesis in the diencephalon.

Authors: Stefanie Ohlig, Solène Clavreul, Manja Thorwirth, Tatiana Simon-Ebert, Riccardo Bocchi, Sabine Ulbricht, Nirmal Kannayian, Moritz Rossner, Swetlana Sirko, Pawel Smialowski, Judith Fischer-Sternjak, Magdalena Götz

Date Published: 2nd Nov 2021

Publication Type: Journal

Abstract (Expand)

Astrocytes are a viable source for generating new neurons via direct conversion. However, little is known about the neurogenic cascades triggered in astrocytes from different regions of the CNS. Here, we examine the transcriptome induced by the proneural factors Ascl1 and Neurog2 in spinal cord-derived astrocytes in vitro. Each factor initially elicits different neurogenic programs that later converge to a V2 interneuron-like state. Intriguingly, patch sequencing (patch-seq) shows no overall correlation between functional properties and the transcriptome of the heterogenous induced neurons, except for K-channels. For example, some neurons with fully mature electrophysiological properties still express astrocyte genes, thus calling for careful molecular and functional analysis. Comparing the transcriptomes of spinal cord- and cerebral-cortex-derived astrocytes reveals profound differences, including developmental patterning cues maintained in vitro. These relate to the distinct neuronal identity elicited by Ascl1 and Neurog2 reflecting their developmental functions in subtype specification of the respective CNS region.

Authors: J Kempf, K Knelles, B A Hersbach, D Petrik, T Riedemann, V Bednarova, A Janjic, T Simon-Ebert, W Enard, P Smialowski, M Götz, G Masserdotti

Date Published: 20th Jul 2021

Publication Type: Journal

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