Linked Life Data

19201858

Source:http://linkedlifedata.com/resource/pubmed/id/19201858

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2009-2-9
pubmed:abstractText
Recently, autophagy has been associated with the TLR signaling pathway to eliminate intracellular pathogens in the innate immune system. However, it is unknown if other pathways regulate autophagy during the immunologic response. Given the critical role of the purinergic P2X7 receptor (P2X7R) pathway during various immunologic functions (i.e., caspase activation and IL-1beta secretion), the principal objective here was to determine whether the P2X7R pathway may regulate autophagy in immune cells. We observed in both MG6 mouse microglial cells and primary microglia that activation of P2X7R by ATP increases the expression of microtubule-associated protein 1 light chain 3 (LC3)-II, the autophagosomal membrane-associated form of LC3, in an extracellular Ca(2+)-dependent manner. Consistent with this, immunohistochemistry showed extensive formation of LC3-immunopositive dots, and electron microscopy demonstrated accumulation of autophagosomes and autophagolysosomes in ATP-treated cells. Importantly, the up-regulation of LC3-II by P2X7R activation was not affected by autophagy inhibitors, such as 3-methyladenine and PI3K inhibitors. Furthermore, while lysosomal functions were impaired by ATP treatment, autophagolysosomal components were released into the extracellular space. Similarly, a phagocytosis assay using Escherichia coli BioParticles showed that phagosome maturation was impaired in ATP-treated cells and a robust release of LC3-immunopositive phagolysosomes was induced along with a radial extension of microtubule bundles. Taken together, the data suggest a novel mechanism whereby the P2X7R signaling pathway may negatively regulate autophagic flux through the impairment of lysosomal functions, leading to stimulation of a release of autophagolysosomes/phagolysosomes into the extracellular space.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1550-6606
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
182
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2051-62
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
The activation of P2X7 receptor impairs lysosomal functions and stimulates the release of autophagolysosomes in microglial cells.
pubmed:affiliation
Transgenic Animal Research Center, National Institute of Agrobiological Sciences, Tsukuba, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't