Screening Protein Aggregation in Cells Using Fluorescent Labels Coupled to Flow Cytometry.

Protein misfolding and aggregation into amyloid conformations have been described to underlie the onset of several human neurodegenerative diseases. Although a large number of biophysical approaches are available to study amyloids in vitro, we still need robust methods to address their self-assembly in living cells. In this context, simple cellular models, like bacteria and yeast, expressing recombinant amyloidogenic proteins are emerging as convenient systems for studying the formation of protein inclusions, their toxicity, propagation, and interactions. We describe here a simple and fast flow cytometry method able to detect intracellular inclusions, as well as to analyze the distribution of the amyloidogenic protein of interest in intact cells. Using specific fluorescent amyloid-dyes, such as thioflavin-S and ProteoStat, or the fusion of fluorescent molecules, such as GFP, the technique can be applied in the quantification of intracellular amyloid content, for the screening of antiamyloidogenic compounds, and to test epigenetic or environmental conditions able to modulate amyloid deposition in vivo.