Publications

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6 Publications visible to you, out of a total of 6

Abstract (Expand)

The medical burden of stroke extends beyond the brain injury itself and is largely determined by chronic comorbidities that develop secondarily. We hypothesized that these comorbidities might share a common immunological cause, yet chronic effects post-stroke on systemic immunity are underexplored. Here, we identify myeloid innate immune memory as a cause of remote organ dysfunction after stroke. Single-cell sequencing revealed persistent pro-inflammatory changes in monocytes/macrophages in multiple organs up to 3 months after brain injury, notably in the heart, leading to cardiac fibrosis and dysfunction in both mice and stroke patients. IL-1β was identified as a key driver of epigenetic changes in innate immune memory. These changes could be transplanted to naive mice, inducing cardiac dysfunction. By neutralizing post-stroke IL-1β or blocking pro-inflammatory monocyte trafficking with a CCR2/5 inhibitor, we prevented post-stroke cardiac dysfunction. Such immune-targeted therapies could potentially prevent various IL-1β-mediated comorbidities, offering a framework for secondary prevention immunotherapy.

Authors: Alba Simats, Sijia Zhang, Denise Messerer, Faye Chong, Sude Beşkardeş, Aparna Sharma Chivukula, Jiayu Cao, Simon Besson-Girard, Felipe A Montellano, Caroline Morbach, Olga Carofiglio, Alessio Ricci, Stefan Roth, Gemma Llovera, Rashween Singh, Yiming Chen, Severin Filser, Nikolaus Plesnila, Christian Braun, Hannah Spitzer, Özgün Gökçe, Martin Dichgans, Peter U Heuschmann, Kinta Hatakeyama, Eduardo Beltrán, Sebastian Clauss, Boyan Bonev, Christian Schulz, Arthur Liesz

Date Published: 22nd Jul 2024

Publication Type: Journal

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

Abstract (Expand)

Understanding the complexity of cellular function within a tissue necessitates the combination of multiple phenotypic readouts. Here, we developed a method that links spatially-resolved gene expression of single cells with their ultrastructural morphology by integrating multiplexed error-robust fluorescence in situ hybridization (MERFISH) and large area volume electron microscopy (EM) on adjacent tissue sections. Using this method, we characterized in situ ultrastructural and transcriptional responses of glial cells and infiltrating T-cells after demyelinating brain injury in male mice. We identified a population of lipid-loaded "foamy" microglia located in the center of remyelinating lesion, as well as rare interferon-responsive microglia, oligodendrocytes, and astrocytes that co-localized with T-cells. We validated our findings using immunocytochemistry and lipid staining-coupled single-cell RNA sequencing. Finally, by integrating these datasets, we detected correlations between full-transcriptome gene expression and ultrastructural features of microglia. Our results offer an integrative view of the spatial, ultrastructural, and transcriptional reorganization of single cells after demyelinating brain injury.

Authors: P. Androvic, M. Schifferer, K. Perez Anderson, L. Cantuti-Castelvetri, H. Jiang, H. Ji, L. Liu, G. Gouna, S. A. Berghoff, S. Besson-Girard, J. Knoferle, M. Simons, O. Gokce

Date Published: 11th Jul 2023

Publication Type: Journal

Abstract (Expand)

Neuroinflammation after stroke is characterized by the activation of resident microglia and the invasion of circulating leukocytes into the brain. Although lymphocytes infiltrate the brain in small number, they have been consistently demonstrated to be the most potent leukocyte subpopulation contributing to secondary inflammatory brain injury. However, the exact mechanism of how this minimal number of lymphocytes can profoundly affect stroke outcome is still largely elusive. Here, using a mouse model for ischemic stroke, we demonstrated that early activation of microglia in response to stroke is differentially regulated by distinct T cell subpopulations - with T(H1) cells inducing a type I INF signaling in microglia and regulatory T cells (T(REG)) cells promoting microglial genes associated with chemotaxis. Acute treatment with engineered T cells overexpressing IL-10 administered into the cisterna magna after stroke induces a switch of microglial gene expression to a profile associated with pro-regenerative functions. Whereas microglia polarization by T cell subsets did not affect the acute development of the infarct volume, these findings substantiate the role of T cells in stroke by polarizing the microglial phenotype. Targeting T cell-microglia interactions can have direct translational relevance for further development of immune-targeted therapies for stroke and other neuroinflammatory conditions.

Authors: C. Benakis, A. Simats, S. Tritschler, S. Heindl, S. Besson-Girard, G. Llovera, K. Pinkham, A. Kolz, A. Ricci, F. J. Theis, S. Bittner, O. Gokce, A. Peters, A. Liesz

Date Published: 13th Dec 2022

Publication Type: Journal

Abstract (Expand)

A hallmark of nervous system aging is a decline of white matter volume and function, but the underlying mechanisms leading to white matter pathology are unknown. In the present study, we found age-related alterations of oligodendrocyte cell state with a reduction in total oligodendrocyte density in aging murine white matter. Using single-cell RNA-sequencing, we identified interferon (IFN)-responsive oligodendrocytes, which localize in proximity to CD8(+) T cells in aging white matter. Absence of functional lymphocytes decreased the number of IFN-responsive oligodendrocytes and rescued oligodendrocyte loss, whereas T-cell checkpoint inhibition worsened the aging response. In addition, we identified a subpopulation of lymphocyte-dependent, IFN-responsive microglia in the vicinity of the CD8(+) T cells in aging white matter. In summary, we provide evidence that CD8(+) T-cell-induced, IFN-responsive oligodendrocytes and microglia are important modifiers of white matter aging.

Authors: T. Kaya, N. Mattugini, L. Liu, H. Ji, L. Cantuti-Castelvetri, J. Wu, M. Schifferer, J. Groh, R. Martini, S. Besson-Girard, S. Kaji, A. Liesz, O. Gokce, M. Simons

Date Published: 26th Oct 2022

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

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