University Medical Center Mainz
Neurology

Author Of 1 Presentation

Experimental Models Oral Presentation

PS06.04 - GlcNAc-signaling as a new target to reduce T cell pathogenicity in the CNS

Speakers
Presentation Number
PS06.04
Presentation Topic
Experimental Models
Lecture Time
13:27 - 13:39

Abstract

Background

Both adaptive and innate immune cells infiltrate the CNS during multiple sclerosis (MS) and in its animal model experimental autoimmune encephalomyelitis (EAE). Pathogenic T cells are known as key drivers of the disease while treatment strategies specifically targeting inflammatory processes directly within the CNS parenchyma behind the blood-brain-barrier are still missing.

Objectives

In this project we aimed to unravel CNS-internal mechanisms to counteract the disease in both the murine and the human system by modulating T cell pathogenicity in the CNS.

Methods

We used intravital 2-photon microscopy to visualize T cells and their interactions with neurons and microglia in the CNS of EAE-diseased animals and in organotypic slice cultures. Using immunohistochemistry and flow cytometry we further analyzed surface molecules on T cells and myeloid cells to gain a deeper understanding of the molecular pathways behind the CNS-response to T cell infiltration. Human T cells isolated from blood and cerebrospinal fluid of MS patients were analyzed ex vivo to allow translation to the human system.

Results

We discovered that detrimental effects of pathogenic Th17 cells can be mediated via a cell-to-cell-interaction-dependent vesicular glutamate release pathway that induces damage in neurons. In a counteractive mechanism, microglia attempted to remove fully viable invaded pathogenic T cells from the CNS tissue during the disease. This T cell engulfment was mediated by expression of activation-dependent lectin and its T cell-binding partner, N-acetyl-D-glucosamine (GlcNAc) and enhancement of GlcNAc signaling in the CNS ameliorated disease outcome. In human subjects, we could show that GlcNAc was highly exposed on T cells in the CNS of MS patients. Of note, this GlcNAc exposure on CNS-infiltrated T cells was significantly increased as compared to peripheral T cells.

Conclusions

Myeloid cells are able to directly react to pathogenic T cell infiltration by engulfing living T cells in a GlcNAc-dependent manner. Increased GlcNAc-exposure on T cells in the human CNS reflects high susceptibility of infiltrated T cells to get eliminated by myeloid cells, suggesting that pharmacological enhancement of T cell engulfment could particularly affect T cells in the target organ of MS.

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Presenter Of 1 Presentation

Experimental Models Oral Presentation

PS06.04 - GlcNAc-signaling as a new target to reduce T cell pathogenicity in the CNS

Speakers
Presentation Number
PS06.04
Presentation Topic
Experimental Models
Lecture Time
13:27 - 13:39

Abstract

Background

Both adaptive and innate immune cells infiltrate the CNS during multiple sclerosis (MS) and in its animal model experimental autoimmune encephalomyelitis (EAE). Pathogenic T cells are known as key drivers of the disease while treatment strategies specifically targeting inflammatory processes directly within the CNS parenchyma behind the blood-brain-barrier are still missing.

Objectives

In this project we aimed to unravel CNS-internal mechanisms to counteract the disease in both the murine and the human system by modulating T cell pathogenicity in the CNS.

Methods

We used intravital 2-photon microscopy to visualize T cells and their interactions with neurons and microglia in the CNS of EAE-diseased animals and in organotypic slice cultures. Using immunohistochemistry and flow cytometry we further analyzed surface molecules on T cells and myeloid cells to gain a deeper understanding of the molecular pathways behind the CNS-response to T cell infiltration. Human T cells isolated from blood and cerebrospinal fluid of MS patients were analyzed ex vivo to allow translation to the human system.

Results

We discovered that detrimental effects of pathogenic Th17 cells can be mediated via a cell-to-cell-interaction-dependent vesicular glutamate release pathway that induces damage in neurons. In a counteractive mechanism, microglia attempted to remove fully viable invaded pathogenic T cells from the CNS tissue during the disease. This T cell engulfment was mediated by expression of activation-dependent lectin and its T cell-binding partner, N-acetyl-D-glucosamine (GlcNAc) and enhancement of GlcNAc signaling in the CNS ameliorated disease outcome. In human subjects, we could show that GlcNAc was highly exposed on T cells in the CNS of MS patients. Of note, this GlcNAc exposure on CNS-infiltrated T cells was significantly increased as compared to peripheral T cells.

Conclusions

Myeloid cells are able to directly react to pathogenic T cell infiltration by engulfing living T cells in a GlcNAc-dependent manner. Increased GlcNAc-exposure on T cells in the human CNS reflects high susceptibility of infiltrated T cells to get eliminated by myeloid cells, suggesting that pharmacological enhancement of T cell engulfment could particularly affect T cells in the target organ of MS.

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