Bioactive Compound Screen for Pharmacological Enhancers of Apolipoprotein E in Primary Human Astrocytes

Pharmacological screening in physiologically relevant brain cells is crucial for identifying neuroactive compounds that better translate into in vivo biology and efficacious therapeutics. Pharmacological enhancement of apolipoprotein E (apoE), a cholesterol-transporting apolipoprotein, has been proposed as a promising therapeutic approach for Alzheimer's disease. Several nuclear receptor agonists were initially shown to increase brain apoE levels together with ATP-binding cassette transporter 1 (ABCA1), but their underlying mechanisms remain unclear. To gain an insight on brain apoE regulation, we performed an unbiased high-throughput screening of known drugs and bioactive compounds in cultured human primary astrocytes, the major apoE-producing cell type in the brain. We have identified several small molecules that increase apoE secretion via previously unknown mechanisms, including those not co-inducing ABCA1. These newly identified compounds are active preferentially in human astrocytes but not in an astrocytoma cell line, furnishing new tools for investigating biological pathways underlying brain apoE production.