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DIDS protects against neuronal injury by blocking Toll‐like receptor 2 activated‐mechanisms
Author(s) -
Yao Hang,
Felfly Hady,
Wang Juan,
Zhou Dan,
Haddad Gabriel G.
Publication year - 2009
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2008.05838.x
Subject(s) - blocking (statistics) , toll , neuroscience , toll like receptor , receptor , pharmacology , chemistry , medicine , biology , immunology , computer science , computer network , innate immune system
Using an in vitro ischemia model (ischemic solution; IS model) that induces penumbral cell death, we examined the effect of 4,4′‐diisothio‐cyanostilbene‐2,2′‐disulfonic acid (DIDS) on cell injury/death and underlying molecular mechanisms. Propidium iodide (PI) uptake was used to quantify cell death in organotypic hippocampal slice cultures. A 24‐h IS exposure caused a fivefold increase in mean PI fluorescence intensity. DIDS, dose‐dependently (1–4000 μM), reduced the IS‐induced PI uptake in hippocampal CA1 neurons with an IC 50 of 26 μM. This protective effect of DIDS was reversible and effective even 6 h following the onset of IS treatment. Gene expression profiling studies indicated that among ∼46 000 transcripts tested, the most significantly up‐regulated gene by IS was interleukin‐1β (IL‐1β) which was also the most significantly down‐regulated gene when DIDS was added to the IS‐treated slices. The addition of a recombinant IL‐1 receptor antagonist (100 μg/mL) or neutralizing IL‐1β antibody significantly attenuated the IS‐induced cell death, indicating that the up‐regulation of IL‐1β with IS treatment contributed to the IS‐induced cell death. Toll‐like receptor 2 (TLR2), another gene that was significantly up‐regulated by IS and suppressed by DIDS, was studied to determine whether it was related to the IL‐1β up‐regulation. Indeed, this was the case as the IS‐induced IL‐1β up‐regulation was abolished in TLR2−/− mouse brain slices. Furthermore, the IS‐induced cell death was significantly reduced in TLR2−/− when compared with that in wild‐type slices, indicating that TLR2 is functionally upstream of IL‐1β in this IS model. We conclude that (i) IS up‐regulates TLR2 expression and augments TLR2 signaling, causing over‐expression of IL‐1β which leads to cell death and (ii) DIDS blocks IS‐induced neuronal injury, at least partially, by suppressing the TLR2 pathway.