Nuclear factor-kappaB activated by capacitative Ca2+ entry enhances muscarinic receptor-mediated soluble amyloid precursor protein (sAPPalpha) release in SH-SY5Y cells.

Abstract

G(q/11) protein-coupled muscarinic receptors are known to regulate the release of soluble amyloid precursor protein (sAPPalpha) produced by alpha-secretase processing; however, their signaling mechanisms remain to be elucidated. It has been reported that a muscarinic agonist activates nuclear factor (NF)-kappaB, a transcription factor that has been shown to play an important role in the Alzheimer disease brain, and that NF-kappaB activation is regulated by intracellular Ca2+ level. In the present study, we investigated whether NF-kappaB activation plays a role in muscarinic receptor-mediated sAPPalpha release enhancement and contributes to a changed capacitative Ca2+ entry (CCE), which was suggested to be involved in the muscarinic receptor-mediated stimulation of sAPPalpha release. Muscarinic receptor-mediated NF-kappaB activation was confirmed by observing the translocation of the active subunit (p65) of NF-kappaB to the nucleus by the muscarinic agonist, oxotremorine M (oxoM), in SH-SY5Y neuroblastoma cells expressing muscarinic receptors that are predominantly of the M3 subtype. NF-kappaB activation and sAPPalpha release enhancement induced by oxoM were inhibited by NF-kappaB inhibitors, such as an NF-kappaB peptide inhibitor (SN50), an IkappaB alpha kinase inhibitor (BAY11-7085), a proteasome inhibitor (MG132), the inhibitor of proteasome activity and IkappaB phosphorylation, pyrrolidine dithiocarbamate, the novel NF-kappaB activation inhibitor (6-amino-4-(4-phenoxyphenylethylamino) quinazoline), and by an intracellular Ca2+ chelator (TMB-8). Furthermore, both oxoM-induced NF-kappaB activation and sAPPalpha release were antagonized by CCE inhibitors (gadolinium or SKF96365) but not by voltage-gated Ca2+-channel blockers. On the other hand, treatment of cells with NF-kappaB inhibitors (SN50, BAY11-7085, MG132, or pyrrolidine dithiocarbamate) did not inhibit muscarinic receptor-mediated CCE. These findings provide evidence for the involvement of NF-kappaB regulated by CCE in muscarinic receptor-mediated sAPPalpha release enhancement.

• Authors: Shinkyu Choi, Jin Hyoung Kim, Eun-Jihn Roh, Moon-Jeong Ko, Ji-Eun Jung, Hwa-Jung Kim
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 281 Issue 18 Pg. 12722-8 (May 05 2006) ISSN: 0021-9258 [Print] United States
• PMID: 16490783 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amyloid beta-Protein Precursor
• BAY 11-7085
• Cysteine Proteinase Inhibitors
• Leupeptins
• NF-kappa B
• Nitriles
• Peptides
• Receptors, Muscarinic
• SN50 peptide
• Sulfones
• Proteasome Endopeptidase Complex
• benzyloxycarbonylleucyl-leucyl-leucine aldehyde
• Calcium

Topics

• Alzheimer Disease (metabolism)
• Amyloid beta-Protein Precursor (metabolism)
• Calcium (metabolism)
• Cell Line, Tumor
• Cell Nucleus (metabolism)
• Cysteine Proteinase Inhibitors (pharmacology)
• Humans
• Leupeptins (pharmacology)
• NF-kappa B (metabolism)
• Nitriles (pharmacology)
• Peptides (chemistry, pharmacology)
• Proteasome Endopeptidase Complex (metabolism)
• Receptors, Muscarinic (metabolism)
• Sulfones (pharmacology)