TY - JOUR
T1 - Inflammatory events in hippocampal slice cultures prime neuronal susceptibility to excitotoxic injury
T2 - A crucial role of P2X7 receptor-mediated IL-1β release
AU - Bernardino, Liliana
AU - Balosso, Silvia
AU - Ravizza, Teresa
AU - Marchi, Nicola
AU - Ku, George
AU - Randle, John C.
AU - Malva, João O.
AU - Vezzani, Annamaria
PY - 2008/7
Y1 - 2008/7
N2 - We investigated the consequences of transient application of specific stimuli mimicking inflammation to hippocampal tissue on microglia activation and neuronal cell vulnerability to a subsequent excitotoxic insult. Two-week-old organotypic hippocampal slice cultures, from 7-day-old C57BL/6 donor mice, were exposed for 3 h to lipopolysaccharide (LPS; 10 ng/mL) followed by 3 h co-incubation with 1 mM ATP, or 100 μM 2′3′-O-(4-benzoyl-benzoyl) adenosine 5′-triphosphate triethylammonium, a selective P2X7 receptor agonist. These treatments in combination, but not individually, induced a pronounced activation and apoptotic-like death of macrophage antigen-1 (MAC-1)-positive microglia associated with a massive release of interleukin (IL)-1β exceeding that induced by LPS alone. Antagonists of P2X7 receptors prevented these effects. Transient pre-exposure of slice cultures to a combination of LPS and P2X7 receptor agonists, but not either one or the other alone, significantly exacerbated CA3 pyramidal cell loss induced by subsequent 12 h exposure to 8 μM α-amino-3-hydroxy-5-methyl-4- isoxazole propinate (AMPA). Potentiation of AMPA toxicity was prevented when IL-1β production or its receptor signaling were blocked by an inhibitor of interleukin-converting-enzyme or IL-1 receptor antagonist during application of LPS + ATP. The same treatments did not prevent microglia apoptosis-like death. These findings show that transient exposure to specific pro-inflammatory stimuli in brain tissue can prime neuronal susceptibility to a subsequent excitotoxic insult. P2X7 receptor stimulation, and the consequent IL-1β release, is mandatory for exacerbation of neuronal loss. These mechanisms may contribute to determine cell death/survival in acute and chronic neurodegenerative conditions associated with inflammatory events.
AB - We investigated the consequences of transient application of specific stimuli mimicking inflammation to hippocampal tissue on microglia activation and neuronal cell vulnerability to a subsequent excitotoxic insult. Two-week-old organotypic hippocampal slice cultures, from 7-day-old C57BL/6 donor mice, were exposed for 3 h to lipopolysaccharide (LPS; 10 ng/mL) followed by 3 h co-incubation with 1 mM ATP, or 100 μM 2′3′-O-(4-benzoyl-benzoyl) adenosine 5′-triphosphate triethylammonium, a selective P2X7 receptor agonist. These treatments in combination, but not individually, induced a pronounced activation and apoptotic-like death of macrophage antigen-1 (MAC-1)-positive microglia associated with a massive release of interleukin (IL)-1β exceeding that induced by LPS alone. Antagonists of P2X7 receptors prevented these effects. Transient pre-exposure of slice cultures to a combination of LPS and P2X7 receptor agonists, but not either one or the other alone, significantly exacerbated CA3 pyramidal cell loss induced by subsequent 12 h exposure to 8 μM α-amino-3-hydroxy-5-methyl-4- isoxazole propinate (AMPA). Potentiation of AMPA toxicity was prevented when IL-1β production or its receptor signaling were blocked by an inhibitor of interleukin-converting-enzyme or IL-1 receptor antagonist during application of LPS + ATP. The same treatments did not prevent microglia apoptosis-like death. These findings show that transient exposure to specific pro-inflammatory stimuli in brain tissue can prime neuronal susceptibility to a subsequent excitotoxic insult. P2X7 receptor stimulation, and the consequent IL-1β release, is mandatory for exacerbation of neuronal loss. These mechanisms may contribute to determine cell death/survival in acute and chronic neurodegenerative conditions associated with inflammatory events.
KW - Apoptosis
KW - Cytokines
KW - Excitotoxicity
KW - Lipopolysaccharide
KW - Organotypic slice cultures
KW - P2X receptors
UR - http://www.scopus.com/inward/record.url?scp=45249094554&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=45249094554&partnerID=8YFLogxK
U2 - 10.1111/j.1471-4159.2008.05387.x
DO - 10.1111/j.1471-4159.2008.05387.x
M3 - Article
C2 - 18384650
AN - SCOPUS:45249094554
VL - 106
SP - 271
EP - 280
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
SN - 0022-3042
IS - 1
ER -