Fig. 1: An Overview of the Screening Approach that Yields Amyloid Inhibitors.

A A schematic of C. elegans anatomy (from WormAtlas; used with permission). The pharynx is green. The area schematized in panels (B, D) is indicated with a black box. The area of the worms photographed in Figs. 2, 5, 6 and 8 is boxed in red. B A schematic that illustrates the anatomy of the pharynx cuticle relative to the lumen and the underlying myoepithelium. C Upon addition of a crystalizing molecule (wact-190 in this example (coloured blue)), the molecule concentrates within minutes in the pharynx cuticle where it forms birefringent objects that grow over time (i.e. crystals). The crystals kill the animals likely through perforation of the underlying myoepithelium and by growing to such an extent that prevents the animal from feeding. Through multiple screening campaigns, we identified 64 crystalizing molecules. A screen of ~2000 molecules for lethality followed by investigation of crystal formation in duplicate requires about 30 days of work. D We screened 2560 molecules for their ability to suppress the lethality associated with crystal formation (and later verified that crystal formation was suppressed), resulting in 85 crystal suppressors identified (depicted in pink). 29 of these molecules (representing 15 of the 45 distinct structural scaffolds among the 85 crystal suppressors) were known amyloid inhibitors. We speculate that amyloid inhibitors can block the ability of amyloid-like material to seed crystal formation. A screen of ~2500 molecules for suppression of crystal-induced lethality followed by detailed investigation of the suppression of crystal formation in duplicate requires about 30 days of work. E We screened a select set of crystal suppressors for their ability to inhibit Aβ42 fibril formation in vitro. We used 8 known amyloid inhibitors and 44 molecules unknown to us to inhibit amyloid formation, revealing 11 (25%) amyloid inhibitors from the latter set. In total, 47% of the crystal suppressors have evidence for their ability to inhibit amyloid formation. A survey of ~80 molecules for their ability to inhibit Aβ42 fibril formation requires about 21 days of work.