Helper CD4 T cells expressing granzyme B cause glial fibrillary acidic protein fragmentation in astrocytes in an MHCII ‐independent manner

Main Points • Helper T cells released granzyme B upon contact with cultured human astrocytes in an MHCII‐independent manner.• Helper T cells caused GFAP fragmentation in a granzyme B and caspase‐dependent manner.• Sublethally injured astrocytes were not apoptotic but had a reduced ability to migrate a nd to support oligodendrocytes. AbstractDuring inflammatory processes of the central nervous system, helper T cells have the capacity to cross the blood –brain barrier and injure or kill neural cells through cytotoxic mechanisms. Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is part of the astrocyte cytoskeleton that can become fragmented in neuroinflammatory conditions. The mechanism of action by which helper T c ells with cytotoxic properties injure astrocytes is not completely understood. Primary human astrocytes were obtained from fetal brain tissue. Human helper (CD4+) T cells were isolated from peripheral blood mononuclear cells and activated with the superantigen staphylococcal enterotoxin E (SEE). Granzyme B was detected by enzyme linked immunosorbent assay and intracellular flow cytometry. GFAP fragmentation was monitored by western blotting. Cell death was monitored by lactic acid dehydrogenase release and terminal biotin ‐dUTP nick labeling (TUNEL). Astrocyte migration was monitored by scratch assay. Adult human oligodendrocytes were cultured with sublethally injured astrocytes to determine support function. Helper T cel...

Source: Glia - November 16, 2018 Category: Neurology Authors: Brandon Stopnicki, Manon Blain, Qiao ‐Ling Cui, Timothy E. Kennedy, Jack P. Antel, Luke M. Healy, Peter J. Darlington Tags: RESEARCH ARTICLE Source Type: research