β1-Integrin– and KV1.3 channel–dependent signaling stimulates glutamate release from Th17 cells
Katharina Birkner, … , Frauke Zipp, Stefan Bittner
Katharina Birkner, … , Frauke Zipp, Stefan Bittner
Published October 29, 2019
Citation Information: J Clin Invest. 2020;130(2):715-732. https://doi.org/10.1172/JCI126381.
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Research Article Autoimmunity Neuroscience

β1-Integrin– and KV1.3 channel–dependent signaling stimulates glutamate release from Th17 cells

Abstract

Although the impact of Th17 cells on autoimmunity is undisputable, their pathogenic effector mechanism is still enigmatic. We discovered soluble N-ethylmaleimide–sensitive factor attachment receptor (SNARE) complex proteins in Th17 cells that enable a vesicular glutamate release pathway that induces local intracytoplasmic calcium release and subsequent damage in neurons. This pathway is glutamine dependent and triggered by binding of β1-integrin to vascular cell adhesion molecule 1 (VCAM-1) on neurons in the inflammatory context. Glutamate secretion could be blocked by inhibiting either glutaminase or KV1.3 channels, which are known to be linked to integrin expression and highly expressed on stimulated T cells. Although KV1.3 is not expressed in CNS tissue, intrathecal administration of a KV1.3 channel blocker or a glutaminase inhibitor ameliorated disability in experimental neuroinflammation. In humans, T cells from patients with multiple sclerosis secreted higher levels of glutamate, and cerebrospinal fluid glutamine levels were increased. Altogether, our findings demonstrate that β1-integrin– and KV1.3 channel–dependent signaling stimulates glutamate release from Th17 cells upon direct cell-cell contact between Th17 cells and neurons.

Authors

Katharina Birkner, Beatrice Wasser, Tobias Ruck, Carine Thalman, Dirk Luchtman, Katrin Pape, Samantha Schmaul, Lynn Bitar, Eva-Maria Krämer-Albers, Albrecht Stroh, Sven G. Meuth, Frauke Zipp, Stefan Bittner

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Figure 9

Intrathecal administration of MgTX ameliorates EAE disease course, and the differentiation of CNS-infiltrating 2D2 cells remains unchanged.

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Intrathecal administration of MgTX ameliorates EAE disease course, and t...
(A) In mice with MOG35–55-induced C57Bl6 EAE, intrathecal injection of MgTX (1.3 ng MgTX/mouse; n = 11 for 2 independent EAE experiments) into the CSF every other day for 14 days, starting on day 7, led to a significant and reproducible reduction in the clinical EAE score compared with the PBS-treated control group (n = 13). (B) In mice with MOG35–55-induced C57Bl6 EAE, intrathecal injection of MgTX (1.3 ng MgTX/mouse, n = 8) into the CSF every other day for 14 days, starting after disease onset (treatment started when the EAE score was >1, on approximately day 12), led to a significant reduction in the clinical EAE score compared with the PBS-treated control group (n = 8 for 2 independent EAE experiments). (C) Intracellular cytokine staining was performed on T lymphocytes ex vivo on day 28. Staining for IL-17 and IFN-γ was analyzed by flow cytometry and is shown as the percentage of CD4+ cells within the CNS and as the MFI of CD4+ cells. n = 4 PBS-treated mice; n = 5 MgTX-treated mice. (D) Cryosections of EAE mouse brains were stained for SMI312 (n = 4–5 sections at least 100 μm apart, from 4 WT and MgTx-treated mice on day 28). Images were acquired using an Olympus microscope equipped with a cellSense camera and analyzed with ImageJ software. Scale bars: 20 μm and 5 μm (enlarged insets). Data indicate the mean ± SEM. *P < 0.05, by multiple Student’s t tests (A and B)or Mann-Whitney U test (C and D).