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P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand

BACKGROUND: The cerebral microvascular occlusion elicits microvascular injury which mimics the different degrees of stroke severity observed in patients, but the mechanisms underlying these embolic injuries are far from understood. The Fas ligand (FasL)-Fas system has been implicated in a number of...

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Autores principales: Lu, Ying-mei, Tao, Rong-rong, Huang, Ji-yun, Li, Li-tao, Liao, Mei-hua, Li, Xiao-ming, Fukunaga, Kohji, Hong, Ze-Hui, Han, Feng
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3420259/
https://www.ncbi.nlm.nih.gov/pubmed/22789015
http://dx.doi.org/10.1186/1742-2094-9-172
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author Lu, Ying-mei
Tao, Rong-rong
Huang, Ji-yun
Li, Li-tao
Liao, Mei-hua
Li, Xiao-ming
Fukunaga, Kohji
Hong, Ze-Hui
Han, Feng
author_facet Lu, Ying-mei
Tao, Rong-rong
Huang, Ji-yun
Li, Li-tao
Liao, Mei-hua
Li, Xiao-ming
Fukunaga, Kohji
Hong, Ze-Hui
Han, Feng
author_sort Lu, Ying-mei
collection PubMed
description BACKGROUND: The cerebral microvascular occlusion elicits microvascular injury which mimics the different degrees of stroke severity observed in patients, but the mechanisms underlying these embolic injuries are far from understood. The Fas ligand (FasL)-Fas system has been implicated in a number of pathogenic states. Here, we examined the contribution of microglia-derived FasL to brain inflammatory injury, with a focus on the potential to suppress the FasL increase by inhibition of the P2X(7)-FasL signaling with pharmacological or genetic approaches during ischemia. METHODS: The cerebral microvascular occlusion was induced by microsphere injection in experimental animals. Morphological changes in microglial cells were studied immunohistochemically. The biochemical analyses were used to examine the intracellular changes of P2X(7)/FasL signaling. The BV-2 cells and primary microglia from mice genetically deficient in P2X(7) were used to further establish a linkage between microglia activation and FasL overproduction. RESULTS: The FasL expression was continuously elevated and was spatiotemporally related to microglia activation following microsphere embolism. Notably, P2X(7) expression concomitantly increased in microglia and presented a distribution pattern that was similar to that of FasL in ED1-positive cells at pathological process of microsphere embolism. Interestingly, FasL generation in cultured microglia cells subjected to oxygen-glucose deprivation-treated neuron-conditioned medium was prevented by the silencing of P2X(7). Furthermore, FasL induced the migration of BV-2 microglia, whereas the neutralization of FasL with a blocking antibody was highly effective in inhibiting ischemia-induced microglial mobility. Similar results were observed in primary microglia from wild-type mice or mice genetically deficient in P2X(7). Finally, the degrees of FasL overproduction and neuronal death were consistently reduced in P2X(7)(−/−) mice compared with wild-type littermates following microsphere embolism insult. CONCLUSION: FasL functions as a key component of an immunoreactive response loop by recruiting microglia to the lesion sites through a P2X(7)-dependent mechanism. The specific modulation of P2X(7)/FasL signaling and aberrant microglial activation could provide therapeutic benefits in acute and subacute phase of cerebral microembolic injury.
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spelling pubmed-34202592012-08-17 P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand Lu, Ying-mei Tao, Rong-rong Huang, Ji-yun Li, Li-tao Liao, Mei-hua Li, Xiao-ming Fukunaga, Kohji Hong, Ze-Hui Han, Feng J Neuroinflammation Research BACKGROUND: The cerebral microvascular occlusion elicits microvascular injury which mimics the different degrees of stroke severity observed in patients, but the mechanisms underlying these embolic injuries are far from understood. The Fas ligand (FasL)-Fas system has been implicated in a number of pathogenic states. Here, we examined the contribution of microglia-derived FasL to brain inflammatory injury, with a focus on the potential to suppress the FasL increase by inhibition of the P2X(7)-FasL signaling with pharmacological or genetic approaches during ischemia. METHODS: The cerebral microvascular occlusion was induced by microsphere injection in experimental animals. Morphological changes in microglial cells were studied immunohistochemically. The biochemical analyses were used to examine the intracellular changes of P2X(7)/FasL signaling. The BV-2 cells and primary microglia from mice genetically deficient in P2X(7) were used to further establish a linkage between microglia activation and FasL overproduction. RESULTS: The FasL expression was continuously elevated and was spatiotemporally related to microglia activation following microsphere embolism. Notably, P2X(7) expression concomitantly increased in microglia and presented a distribution pattern that was similar to that of FasL in ED1-positive cells at pathological process of microsphere embolism. Interestingly, FasL generation in cultured microglia cells subjected to oxygen-glucose deprivation-treated neuron-conditioned medium was prevented by the silencing of P2X(7). Furthermore, FasL induced the migration of BV-2 microglia, whereas the neutralization of FasL with a blocking antibody was highly effective in inhibiting ischemia-induced microglial mobility. Similar results were observed in primary microglia from wild-type mice or mice genetically deficient in P2X(7). Finally, the degrees of FasL overproduction and neuronal death were consistently reduced in P2X(7)(−/−) mice compared with wild-type littermates following microsphere embolism insult. CONCLUSION: FasL functions as a key component of an immunoreactive response loop by recruiting microglia to the lesion sites through a P2X(7)-dependent mechanism. The specific modulation of P2X(7)/FasL signaling and aberrant microglial activation could provide therapeutic benefits in acute and subacute phase of cerebral microembolic injury. BioMed Central 2012-07-12 /pmc/articles/PMC3420259/ /pubmed/22789015 http://dx.doi.org/10.1186/1742-2094-9-172 Text en Copyright ©2012 han et al. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Lu, Ying-mei
Tao, Rong-rong
Huang, Ji-yun
Li, Li-tao
Liao, Mei-hua
Li, Xiao-ming
Fukunaga, Kohji
Hong, Ze-Hui
Han, Feng
P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand
title P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand
title_full P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand
title_fullStr P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand
title_full_unstemmed P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand
title_short P2X(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of Fas ligand
title_sort p2x(7) signaling promotes microsphere embolism-triggered microglia activation by maintaining elevation of fas ligand
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3420259/
https://www.ncbi.nlm.nih.gov/pubmed/22789015
http://dx.doi.org/10.1186/1742-2094-9-172
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