Thioflavin-S Staining of Bacterial Inclusion Bodies for the Fast, Simple, and Inexpensive Screening of Amyloid Aggregation Inhibitors

Synthesis and Multitarget Biological Profiling of a Novel Family of Rhein Derivatives As Disease-Modifying Anti-Alzheimer Agents

“…Because IBs contain highly ordered amyloid-like structures and their formation seems to share mechanistic features with amyloid self-assembly, they have been recently proposed as a model to study amyloid aggregation. 72,73 We have recently developed a methodology that allows a fast, simple, and inexpensive evaluation of the anti-aggregating activity of putative inhibitors, which is based on the in vivo staining with thioflavin S of IBs in intact E. coli cells that overexpress a given amyloidogenic protein in the presence and absence of the inhibitors, and monitoring of the corresponding changes in the fluorescence of thioflavin S. 74 The applicability of this method to the screening of both Aβ42 and tau aggregation inhibitors has been recently demonstrated. 74 Worthy of note, the Aβ42 anti-aggregating activities determined through this method for a number of known active and inactive inhibitors were very similar to those previously reported in in vitro assays using synthetic peptides, thereby validating this methodology.…”

“…72,73 We have recently developed a methodology that allows a fast, simple, and inexpensive evaluation of the anti-aggregating activity of putative inhibitors, which is based on the in vivo staining with thioflavin S of IBs in intact E. coli cells that overexpress a given amyloidogenic protein in the presence and absence of the inhibitors, and monitoring of the corresponding changes in the fluorescence of thioflavin S. 74 The applicability of this method to the screening of both Aβ42 and tau aggregation inhibitors has been recently demonstrated. 74 Worthy of note, the Aβ42 anti-aggregating activities determined through this method for a number of known active and inactive inhibitors were very similar to those previously reported in in vitro assays using synthetic peptides, thereby validating this methodology. 74 A potential limitation of this method lies in the fact that only compounds that are membrane permeable can be detected, whereas potential hits that are active as aggregation inhibitors but unable to cross biological membranes would remain undetected.…”

Shogaol–huprine hybrids: Dual antioxidant and anticholinesterase agents with β-amyloid and tau anti-aggregating properties

“…In the latter case, the fluorescence is determined using image processing programs. Of note, we have shown that the results obtained in the screening of inhibitors of Aβ42 aggregation correlate well with the Aβ anti-aggregating activity values found in vitro using synthetic Aβ42, 21 this methodology thus emerging as a economic surrogate of the classical in vitro tests.…”

“…Taking advantage of the fact that amyloid aggregation can be followed in vivo in bacteria, we have recently developed a methodology that allows the fast, easy, and inexpensive screening of inhibitors of the spontaneous aggregation of potentially any amyloidogenic protein that can be overexpressed in Escherichia coli cells. 21 When these proteins aggregate inside E. coli they usually form IBs that can be stained with Thioflavin-S (Th-S). The extent of aggregation of those proteins can be monitored measuring the variations of the fluorescence of Th-S.…”

“…Of note, in line with the increasingly accepted notion that the aggregation of amyloidogenic proteins, such as Aβ and tau, might share common mechanisms and might be tackled by the same drugs, 19 we have recently reported that several AChE inhibitor (huprine or tacrine)-based hybrid compounds display a dual Aβ and tau antiaggregating action, hereby broadening their multitarget profile. 20,21 [6]-Shogaol (1, Fig. 1) is one of the major bioactive constituents of ginger (Zingiber officinale), a plant used worldwide as a spice and also widely used in the Chinese traditional medicine.…”