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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2002-11-27
pubmed:abstractText
The role of the common neurotrophin receptor p75 (p75NTR) in neuronal survival and cell death remains controversial. On the one hand, p75NTR provides a positive modulatory influence on nerve growth factor (NGF) signaling through the high affinity neurotrophin receptor TrkA, and hence increases NGF survival signaling. However, p75NTR may also signal independently of TrkA, causing cell death or cell survival, depending on the cell type and stage of development. Here we demonstrate that TrkA is expressed in primary cultures of hippocampal neurons and is activated by NGF within 10 min of exposure. In primary hippocampal cultures neuroprotection by NGF against glutamate toxicity was mediated by NF-kappaB and accompanied by an increased expression of neuroprotective NF-kappaB target genes Bcl-2 and Bcl-xl. In mouse hippocampal cells lacking p75NTR (p75NTR-/-) activation of TrkA by NGF was not detectable. Moreover, neuroprotection by NGF against glutamate toxicity was abolished in p75NTR-/- neurons, and the expression of bcl-2 and bcl-xl was markedly reduced as compared to wildtype cells. NGF increased TrkA phosphorylation in hippocampal neurons and provided protection that required phosphoinositol-3-phosphate (PI3)-kinase activity and Akt phosphorylation, whereas the mitogen-activated protein kinases (MAPK), extracellular-regulated kinases (Erk) 1/2, were not involved. P75NTR signaling independent of TrkA, such as increased neutral sphingomyelinase (NSMase) activity causing enhanced levels of ceramide, were not detected after exposure of hippocampal neurons to NGF. Interestingly, inhibition of sphingosine-kinase blocked the neuroprotective effect of NGF, suggesting that sphingosine-1-phosphate was also involved in NGF-mediated survival in our cultured hippocampal neurons. Overall, our results indicate an essential role for p75NTR in supporting NGF-triggered TrkA signaling pathways mediating neuronal survival in hippocampal neurons.
pubmed:language
eng
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Akt1 protein, rat, http://linkedlifedata.com/resource/pubmed/chemical/Brain-Derived Neurotrophic Factor, http://linkedlifedata.com/resource/pubmed/chemical/Excitatory Amino Acid Agonists, http://linkedlifedata.com/resource/pubmed/chemical/NF-kappa B, http://linkedlifedata.com/resource/pubmed/chemical/Nerve Growth Factor, http://linkedlifedata.com/resource/pubmed/chemical/Neuroprotective Agents, http://linkedlifedata.com/resource/pubmed/chemical/Phosphatidylinositol 3-Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Phosphotransferases (Alcohol Group..., http://linkedlifedata.com/resource/pubmed/chemical/Protein-Serine-Threonine Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Proto-Oncogene Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Proto-Oncogene Proteins c-akt, http://linkedlifedata.com/resource/pubmed/chemical/RNA, Messenger, http://linkedlifedata.com/resource/pubmed/chemical/Receptor, Nerve Growth Factor, http://linkedlifedata.com/resource/pubmed/chemical/Receptor, trkA, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Nerve Growth Factor, http://linkedlifedata.com/resource/pubmed/chemical/sphingosine kinase
pubmed:status
MEDLINE
pubmed:author
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1089-108
pubmed:dateRevised
2010-11-18
pubmed:articleTitle
Nerve growth factor survival signaling in cultured hippocampal neurons is mediated through TrkA and requires the common neurotrophin receptor P75.
pubmed:affiliation
Institut für Pharmakologie und Toxikologie, Philipps-Universität Marburg, Ketzerbach 63, 35032, Marburg, Germany. culmsee@mailer.uni-marburg.de