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P3–076: Palmitate induces transcriptional regulation of BACE1 and presenilin by STAT3 in neurons mediated by astrocytes
Author(s) -
Liu Li,
Martin Rebecca,
Kohler Garrett,
Chan Christina
Publication year - 2013
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2013.05.1146
Subject(s) - presenilin , calpain , downregulation and upregulation , cyclin dependent kinase 5 , microbiology and biotechnology , chemistry , amyloid precursor protein secretase , amyloid precursor protein , astrocyte , kinase , alzheimer's disease , biology , biochemistry , protein kinase a , neuroscience , medicine , mitogen activated protein kinase kinase , enzyme , central nervous system , disease , gene
Deregulation of calcium has been implicated in neurodegenerative diseases, including Alzheimer’s disease (AD). Previously, we showed that saturated free-fatty acid, palmitate, causes AD-like changes in primary cortical neurons mediated by astrocytes. However, the molecular mechanisms by which conditioned media from astrocytes cultured in palmitate induces AD-like changes in neurons are unknown. This study demonstrates that this condition media from astrocytes elevates calcium level in the neurons, which subsequently increases calpain activity, a calcium-dependent protease, leading to enhance p25/Cdk5 activity and phosphorylation and activation of the STAT3 (signal transducer and activator of transcription) transcription factor. Inhibiting calpain or Cdk5 significantly reduces the upregulation in nuclear level of pSTAT3, which we found to transcriptionally regulate both BACE1 and presenilin-1, the latter is a catalytic subunit of γsecretase. Decreasing pSTAT3 levels reduced the mRNA levels of both BACE1 and presenilin-1 to near control levels. These data demonstrate a signal pathway leading to the activation of STAT3, and the generation of the amyloid peptide. Thus, our results suggest that STAT3 is an important potential therapeutic target of AD pathogenesis.