Astrocytes are important mediators of Aβ-induced neurotoxicity and tau phosphorylation in primary culture

• Published in: Cell death & disease Vol. 2; no. 6; p. e167
• Main Authors: Garwood, C J, Pooler, A M, Atherton, J, Hanger, D P, Noble, W
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2011; Nature Publishing Group
• Subjects: 631/378/2596/1308; 631/80/304; 692/699/375/365/1283; Amyloid beta-Peptides - toxicity; Animals; Antibodies; Astrocytes - cytology; Astrocytes - drug effects; Astrocytes - metabolism; Biochemistry; Biomedical and Life Sciences; Cell Biology; Cell Culture; Cell Death - drug effects; Cells, Cultured; Immunology; Life Sciences; Neurons - cytology; Neurons - drug effects; Neurons - metabolism; Original; original-article; Peptide Fragments - toxicity; Phosphorylation - drug effects; Rats; tau Proteins - metabolism; tau; amyloid; astrocytes; inflammation; Alzheimer's disease; minocycline
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/cddis.2011.50

Alzheimer's disease (AD) is pathologically characterised by the age-dependent deposition of β -amyloid (A β ) in senile plaques, intraneuronal accumulation of tau as neurofibrillary tangles, synaptic dysfunction and neuronal death. Neuroinflammation, typified by the accumulation of activated microglia and reactive astrocytes, is believed to modulate the development and/or progression of AD. We have used primary rat neuronal, astrocytic and mixed cortical cultures to investigate the contribution of astrocyte-mediated inflammatory responses during A β -induced neuronal loss. We report that the presence of small numbers of astrocytes exacerbate A β -induced neuronal death, caspase-3 activation and the production of caspase-3-cleaved tau. Furthermore, we show that astrocytes are essential for the A β -induced tau phosphorylation observed in primary neurons. The release of soluble inflammatory factor(s) from astrocytes accompanies these events, and inhibition of astrocyte activation with the anti-inflammatory agent, minocycline, reduces astrocytic inflammatory responses and the associated neuronal loss. A β -induced increases in caspase-3 activation and the production of caspase-3-truncated tau species in neurons were reduced when the astrocytic response was attenuated with minocycline. Taken together, these results show that astrocytes are important mediators of the neurotoxic events downstream of elevated A β in models of AD, and suggest that mechanisms underlying pro-inflammatory cytokine release might be an important target for therapy.