Kainate mediates nuclear factor-kappa B activation in hippocampus via phosphatidylinositol-3 kinase and extracellular signal-regulated protein kinase.
The transcription factor nuclear factor-kappa B (NF-kappaB) is an inducible regulator of genes that plays a crucial role in the nervous system. Glutamate receptor stimulation is one well-described mechanism for NF-kappaB activation. In the studies presented here we used the glutamate analog, kainate to investigate the signaling mechanisms that couple to NF-kappaB activation in hippocampus. Kainate (250 nM) application to hippocampal slices elicited a time-dependent increase in nuclear NF-kappaB levels in areas CA3 and CA1, but not dentate, compared with controls. Further analysis focused on hippocampal area CA3, revealed increased NF-kappaB DNA binding activity in response to kainate stimulation. Supershift electrophoretic mobility shift assay indicated that the kainate-mediated NF-kappaB complex binding DNA was composed of p65, p50, and c-Rel subunits. Through inhibition studies we found that extracellular signal-regulated protein kinase (ERK) and phosphatidylinositol-3 kinase (PI3K) couple to basal and kainate-mediated NF-kappaB DNA binding activity in area CA3. Kainate elicited decreased total and increased phospho-inhibitor kappa B alpha (IkappaBalpha), suggesting that kainate-mediated activation of NF-kappaB is via the classical IkappaB kinase pathway. Interestingly, inhibition of ERK but not PI3K blocked the kainate-mediated increase in phospho-IkappaBalpha. Thus, our findings support a role for the ERK and PI3K pathways in kainate-mediated NF-kappaB activation in hippocampal area CA3, but these kinases may target the NF-kappaB pathway at different loci.
Lubin
F D
FD
The Cain Foundation Laboratories, Texas Children's Hospital, Department of Pediatrics, MC 3-6365, 1102 Bates Street, Houston, TX 77030-2399, USA.
Johnston
L D
LD
Sweatt
J D
JD
Anderson
A E
AE
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002867:Chromones / Q000494:pharmacology; D004347:Drug Interactions; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D007150:Immunohistochemistry / Q000379:methods; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology*; D034921:Lamin Type B / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000502:physiology*; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
D002867:Chromones; D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D005419:Flavonoids; D034921:Lamin Type B; D009025:Morpholines; D016328:NF-kappa B; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D020930:MAP Kinase Kinase Kinases; D007608:Kainic Acid; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one