Both serum cholesterol levels and the cholesterol carrying protein ApoE have been implicated in the
development of Alzheimer’s disease. Despite intensive research, there is not a consensus for why
hypercholesterolemia and ApoE are risk factors. In the brain, the majority of cholesterol and ApoE are made by
astrocytes. We will use a recently created cholesterol probe as a novel approach to investigate how ApoE
isoform impacts trafficking of cholesterol out of the astrocyte and into the neuron. This probe contains a
photoactivatable group which creates covalent bonds to adjacent proteins. In addition, it has a click-chemistry
group which allows probe-protein complex purification for mass spectrometry analysis. We will add the
cholesterol probe to astrocyte lines expressing each of the human ApoE isoforms. With this approach we will
answer the questions:
1. What are the cholesterol-protein interactions within astrocyte-secreted ApoE particles and how are these
interactions impacted by ApoE isoform?
2. What are the cholesterol-protein interactions in the neuron which can be linked to Alzheimer’s disease
associated genes, and are these interactions in the neuron impacted by ApoE isoform?
Using this approach, we believe we will identify how some known Alzheimer’s disease risk alleles are
connected to cholesterol/ApoE, and identify proteins not previously implicated in Alzheimer’s disease that are
modified by cholesterol and may be contributing to the development of the disease.