Lack of junctional adhesion molecule (JAM)-B ameliorates experimental autoimmune encephalomyelitis.

Tietz, Silvia; Périnat, Therese; Greene, Gretchen Thompson; Enzmann, Gaby; Deutsch, Urban; Adams, Ralf; Imhof, Beat; Aurrand-Lions, Michel; Engelhardt, Britta (2018). Lack of junctional adhesion molecule (JAM)-B ameliorates experimental autoimmune encephalomyelitis. Brain, behavior, and immunity, 73, pp. 3-20. Elsevier 10.1016/j.bbi.2018.06.014

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In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) autoaggressive CD4 T cells cross the blood-brain barrier (BBB) and cause neuroinflammation. Therapeutic targeting of CD4 T-cell trafficking into the CNS by blocking α4-integrins has proven beneficial for the treatment of MS but comes with associated risks, probably due to blocking CD8 T cell mediated CNS immune surveillance. Our recent observations show that CD8 T cells also rely on α4β1-integrins to cross the BBB. Besides vascular cell adhesion molecule-1 (VCAM-1), we identified junctional adhesion molecule-B (JAM-B) as a novel vascular α4β1-integrin ligand involved in CD8 T-cell migration across the BBB. This prompted us to investigate, if JAM-B also mediates CD4 T-cell migration across the BBB. We first ensured that encephalitogenic T cells can bind to JAM-B in vitro and next compared EAE pathogenesis in JAM-B C57BL/6J mice and their wild-type littermates. Following immunization with MOG peptide, JAM-B mice developed ameliorated EAE compared to their wild-type littermates. At the same time, we isolated higher numbers of CD45 infiltrating immune cells from the CNS of JAM-B C57BL/6J mice suffering from EAE. Immunofluorescence staining revealed that the majority of CD45 inflammatory cells accumulated in the leptomeningeal and perivascular spaces of the CNS behind the BBB but do not gain access to the CNS parenchyma. Trapping of CNS inflammatory cells was not due to increased inflammatory cell proliferation. Neither a loss of BBB integrity or BBB polarity potentially affecting local chemokine gradients nor a lack of focal gelatinase activation required for CNS parenchymal immune cell entry across the glia limitans could be detected in JAM-B mice. Lack of a role for JAM-B in the effector phase of EAE was supported by the observation that we did not detect any role for JAM-B in EAE pathogenesis, when EAE was elicited by in vitro activated MOG specific CD4 effector T cells. On the other hand, we also failed to demonstrate any role of JAM-B in in vivo priming, proliferation or polarization of MOG-specific CD4 T cells in peripheral immune organs. Finally, our study excludes expression of and thus a role for JAM-B on peripheral and CNS infiltrating myeloid cells. Taken together, although endothelial JAM-B is not required for immune cell trafficking across the BBB in EAE, in its absence accumulation of inflammatory cells mainly in CNS leptomeningeal spaces leads to amelioration of EAE.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Theodor Kocher Institute
09 Interdisciplinary Units > Microscopy Imaging Center MIC

UniBE Contributor:

Tietz, Silvia; Périnat, Therese; Greene, Gretchen Thompson; Enzmann, Gaby; Deutsch, Urban and Engelhardt, Britta

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

0889-1591

Publisher:

Elsevier

Language:

English

Submitter:

Ursula Zingg-Zünd

Date Deposited:

25 Feb 2019 16:17

Last Modified:

23 Oct 2019 14:00

Publisher DOI:

10.1016/j.bbi.2018.06.014

PubMed ID:

29920328

Uncontrolled Keywords:

Blood-brain barrier Experimental autoimmune encephalomyelitis Gelatinases Glia limitans Junctional adhesion molecules Tight junctions

BORIS DOI:

10.7892/boris.124085

URI:

https://boris.unibe.ch/id/eprint/124085

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