Publications

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28 Publications visible to you, out of a total of 28

Abstract (Expand)

Multidimensional single-cell analyses of T cells have fueled the debate about whether there is extensive plasticity or 'mixed' priming of helper T cell subsets in vivo. Here, we developed an experimental framework to probe the idea that the site of priming in the systemic immune compartment is a determinant of helper T cell-induced immunopathology in remote organs. By site-specific in vivo labeling of antigen-specific T cells in inguinal (i) or gut draining mesenteric (m) lymph nodes, we show that i-T cells and m-T cells isolated from the inflamed central nervous system (CNS) in a model of multiple sclerosis (MS) are distinct. i-T cells were Cxcr6(+), and m-T cells expressed P2rx7. Notably, m-T cells infiltrated white matter, while i-T cells were also recruited to gray matter. Therefore, we propose that the definition of helper T cell subsets by their site of priming may guide an advanced understanding of helper T cell biology in health and disease.

Authors: M. Hiltensperger, E. Beltran, R. Kant, S. Tyystjarvi, G. Lepennetier, H. Dominguez Moreno, I. J. Bauer, S. Grassmann, S. Jarosch, K. Schober, V. R. Buchholz, S. Kenet, C. Gasperi, R. Ollinger, R. Rad, A. Muschaweckh, C. Sie, L. Aly, B. Knier, G. Garg, A. M. Afzali, L. A. Gerdes, T. Kumpfel, S. Franzenburg, N. Kawakami, B. Hemmer, D. H. Busch, T. Misgeld, K. Dornmair, T. Korn

Date Published: 9th Jun 2021

Publication Type: Journal

Abstract (Expand)

Aging results in gray and white matter degeneration, but the specific microglial responses are unknown. Using single-cell RNA sequencing from white and gray matter separately, we identified white matter-associated microglia (WAMs), which share parts of the disease-associated microglia (DAM) gene signature and are characterized by activation of genes implicated in phagocytic activity and lipid metabolism. WAMs depend on triggering receptor expressed on myeloid cells 2 (TREM2) signaling and are aging dependent. In the aged brain, WAMs form independent of apolipoprotein E (APOE), in contrast to mouse models of Alzheimer's disease, in which microglia with the WAM gene signature are generated prematurely and in an APOE-dependent pathway similar to DAMs. Within the white matter, microglia frequently cluster in nodules, where they are engaged in clearing degenerated myelin. Thus, WAMs may represent a potentially protective response required to clear degenerated myelin accumulating during white matter aging and disease.

Authors: S. Safaiyan, S. Besson-Girard, T. Kaya, L. Cantuti-Castelvetri, L. Liu, H. Ji, M. Schifferer, G. Gouna, F. Usifo, N. Kannaiyan, D. Fitzner, X. Xiang, M. J. Rossner, M. Brendel, O. Gokce, M. Simons

Date Published: 7th Apr 2021

Publication Type: Journal

Abstract (Expand)

In the present study, we have demonstrated that extracellular vesicles (EVs) derived from cerebrospinal fluid (CSF) represent a promising source for the identification of a novel miRNA signatures in Parkinson's disease (PD). Using next‐generation small‐RNA sequencing, we present for the first time the complete and quantitative microRNAome of EVs isolated from human CSF of PD and age‐correlated controls (CTR). In parallel, we performed CSF proteomic profiling of overlapping patient cohorts, which revealed the deregulation of disease‐relevant pathways similar to the ones obtained with the parallel miRNA analyses, supporting the results for the identified signature.

Authors: Lucas Caldi Gomes, Anna-Elisa Roser, Gaurav Jain, Tonatiuh Pena Centeno, Fabian Maass, Lukas Schilde, Caroline May, Anja Schneider, Mathias Bähr, Katrin Marcus, André Fischer, Paul Lingor

Date Published: 5th Apr 2021

Publication Type: Journal

Abstract (Expand)

Neural stem cells (NSCs) in the adult brain transit from the quiescent state to proliferation to produce new neurons. The mechanisms regulating this transition in freely behaving animals are, however, poorly understood. We customized in vivo imaging protocols to follow NSCs for several days up to months, observing their activation kinetics in freely behaving mice. Strikingly, NSC division is more frequent during daylight and is inhibited by darkness-induced melatonin signaling. The inhibition of melatonin receptors affected intracellular Ca<sup>2+</sup> dynamics and promoted NSC activation. We further discovered a Ca<sup>2+</sup> signature of quiescent versus activated NSCs and showed that several microenvironmental signals converge on intracellular Ca<sup>2+</sup> pathways to regulate NSC quiescence and activation. In vivo NSC-specific optogenetic modulation of Ca<sup>2+</sup> fluxes to mimic quiescent-state-like Ca<sup>2+</sup> dynamics in freely behaving mice blocked NSC activation and maintained their quiescence, pointing to the regulatory mechanisms mediating NSC activation in freely behaving animals.

Authors: Archana Gengatharan, Sarah Malvaut, Alina Marymonchyk, Majid Ghareghani, Marina Snapyan, Judith Fischer-Sternjak, Jovica Ninkovic, Magdalena Götz, Armen Saghatelyan

Date Published: 4th Feb 2021

Publication Type: Journal

Abstract (Expand)

Cortical pathology contributes to chronic cognitive impairment of patients suffering from the neuroinflammatory disease multiple sclerosis (MS). How such gray matter inflammation affects neuronal structure and function is not well understood. In the present study, we use functional and structural in vivo imaging in a mouse model of cortical MS to demonstrate that bouts of cortical inflammation disrupt cortical circuit activity coincident with a widespread, but transient, loss of dendritic spines. Spines destined for removal show local calcium accumulations and are subsequently removed by invading macrophages or activated microglia. Targeting phagocyte activation with a new antagonist of the colony-stimulating factor 1 receptor prevents cortical synapse loss. Overall, our study identifies synapse loss as a key pathological feature of inflammatory gray matter lesions that is amenable to immunomodulatory therapy.

Authors: Mehrnoosh Jafari, Adrian-Minh Schumacher, Nicolas Snaidero, Emily M Ullrich Gavilanes, Tradite Neziraj, Virág Kocsis-Jutka, Daniel Engels, Tanja Jürgens, Ingrid Wagner, Juan Daniel Flórez Weidinger, Stephanie S Schmidt, Eduardo Beltrán, Nellwyn Hagan, Lisa Woodworth, Dimitry Ofengeim, Joseph Gans, Fred Wolf, Mario Kreutzfeldt, Ruben Portugues, Doron Merkler, Thomas Misgeld, Martin Kerschensteiner

Date Published: 25th Jan 2021

Publication Type: Journal

Abstract (Expand)

Rationale: Arterial inflammation manifested as atherosclerosis is the leading cause of mortality worldwide. Genome-wide association studies have identified a prominent role of HDAC (histone deacetylase)-9 in atherosclerosis and its clinical complications including stroke and myocardial infarction. Objective: To determine the mechanisms linking HDAC9 to these vascular pathologies and explore its therapeutic potential for atheroprotection. Methods and Results: We studied the effects of Hdac9 on features of plaque vulnerability using bone marrow reconstitution experiments and pharmacological targeting with a small molecule inhibitor in hyperlipidemic mice. We further used 2-photon and intravital microscopy to study endothelial activation and leukocyte-endothelial interactions. We show that hematopoietic Hdac9 deficiency reduces lesional macrophage content while increasing fibrous cap thickness thus conferring plaque stability. We demonstrate that HDAC9 binds to IKK (inhibitory kappa B kinase)-α and β, resulting in their deacetylation and subsequent activation, which drives inflammatory responses in both macrophages and endothelial cells. Pharmacological inhibition of HDAC9 with the class IIa HDAC inhibitor TMP195 attenuates lesion formation by reducing endothelial activation and leukocyte recruitment along with limiting proinflammatory responses in macrophages. Transcriptional profiling using RNA sequencing revealed that TMP195 downregulates key inflammatory pathways consistent with inhibitory effects on IKKβ. TMP195 mitigates the progression of established lesions and inhibits the infiltration of inflammatory cells. Moreover, TMP195 diminishes features of plaque vulnerability and thereby enhances plaque stability in advanced lesions. Ex vivo treatment of monocytes from patients with established atherosclerosis reduced the production of inflammatory cytokines including IL (interleukin)-1β and IL-6. Conclusions: Our findings identify HDAC9 as a regulator of atherosclerotic plaque stability and IKK activation thus providing a mechanistic explanation for the prominence of HDAC9 as a vascular risk locus in genome-wide association studies. Its therapeutic inhibition may provide a potent lever to alleviate vascular inflammation.

Authors: Yaw Asare, Thomas A Campbell-James, Yury Bokov, Lydia Luya Yu, Matthias Prestel, Omar El Bounkari, Stefan Roth, Remco T A Megens, Tobias Straub, Kyra Thomas, Guangyao Yan, Melanie Schneider, Natalie Ziesch, Steffen Tiedt, Carlos Silvestre-Roig, Quinte Braster, Yishu Huang, Manuela Schneider, Rainer Malik, Christof Haffner, Arthur Liesz, Oliver Soehnlein, Jürgen Bernhagen, Martin Dichgans

Date Published: 28th Aug 2020

Publication Type: Journal

Abstract (Expand)

Multiple sclerosis (MS) is a disabling disease of the CNS. Inflammatory features of MS include lymphocyte accumulations in the CNS and cerebrospinal fluid (CSF). The preclinical events leading to established MS are still enigmatic. Here we compared gene expression patterns of CSF cells from MS-discordant monozygotic twin pairs. Six "healthy" co-twins, who carry a maximal familial risk for developing MS, showed subclinical neuroinflammation (SCNI) with small MRI lesions. Four of these subjects had oligoclonal bands (OCBs). By single-cell RNA sequencing of 2752 CSF cells, we identified clonally expanded CD8+ T cells, plasmablasts, and, to a lesser extent, CD4+ T cells not only from MS patients but also from subjects with SCNI. In contrast to nonexpanded T cells, clonally expanded T cells showed characteristics of activated tissue-resident memory T (TRM) cells. The TRM-like phenotype was detectable already in cells from SCNI subjects but more pronounced in cells from patients with definite MS. Expanded plasmablast clones were detected only in MS and SCNI subjects with OCBs. Our data provide evidence for very early concomitant activation of 3 components of the adaptive immune system in MS, with a notable contribution of clonally expanded TRM-like CD8+ cells.

Authors: E. Beltran, L. A. Gerdes, J. Hansen, A. Flierl-Hecht, S. Krebs, H. Blum, B. Ertl-Wagner, F. Barkhof, T. Kumpfel, R. Hohlfeld, K. Dornmair

Date Published: 1st Nov 2019

Publication Type: Journal

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