Cells that protect and nurture neurons deliver a suicide package in patients in Alzheimer's.
While some amyloid is excreted by all neurons, the elevated levels associated with Alzheimer's cause an unusual response in astrocytes. These are the cells which normally provide blood, oxygen and nutrients to the brain.
Astrocytes react to high amyloid levels by including the protein PAR-4 in lipid ceremide.
Alone PAR-4 is damaging to cells but combined with lipid ceremide it kills the neuron and the astrocyte.
"If the neuron makes something toxic and dumps it at your door, what would you do?" said Dr Erhard Bieberich, biochemist at the Medical College of Georgia at Georgia Health Sciences University and corresponding author of the study.
"You would probably do something to defend yourself."
She noted that scientists have long hypothosysed that something other than excess amyloid must be causing brain cell death or the neurons would die before they could produce very large plaques.
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