Biology subjects

Garfagnini, T.

Publications and source records attributed to Garfagnini, T..

2 recordsLinked to original sources

bioRxiv2023

Fibril Paint to detect Amyloids and determine Fibril Length

Tau aggregation into amyloid fibrils is linked to the development of neurodegenerative diseases, including Alzheimers Disease. The molecular processes underlying aggregation in disease are poorly understood. Here, we introduce FibrilPaint1 as a tool to measure the size of Tau amyloid fibrils in fluids, from early aggregation stages to mature fibrils. FibrilPaint1 is a 22mer peptide with many exciting properties, which makes it a tool for diagnostics and an attractive start point for developing a class of effective fibril targeting degraders: (i) FibrilPaint1 binds fibrils with nanomolar affinity; (ii) it does also bind to oligomeric precursors, down to a size of only 4 layers; (iii) it does not bind to monomers (KD > 100 {micro}M); (iv) it is fluorescently labelled, which allows monitoring and localising interactions. (v) FibrilPaint1 recognises various Tau fibrils, including patient derived fibrils from Alzheimer, Corticobasal degeneration and Frontotemporal dementia; (vi) FibrilPaint1 is selective for the amyloid state and does not have background binding to amorphous aggregates, blood serum or cell lysate. In combination with Flow Induced Dispersion Analysis (FIDA), a microfluidics technology, we determined the molecular size of amyloid fibrils with sub-microliter sample volumes. This set-up acts as a molecular ruler at layer resolution - we determined Tau fibril length from 4 to 1100 layers in solution. This is an interesting parameter that can be used for diagnostic applications and biochemical research in dementia.

biochemistry↗

bioRxiv2022

A peptide strategy for inhibiting different protein aggregation pathways in disease

Protein aggregation correlates with many human diseases. Protein aggregates differ in shape, ranging from amorphous aggregates to amyloid fibrils. Possibly for such heterogeneity, strategies to develop effective aggregation inhibitors that reach the clinic failed so far. Here, we present a new strategy by which we developed a family of peptides targeting early aggregation stages for both amorphous and fibrillar aggregates of proteins unrelated in sequence and structure. Thus, they act on dynamic precursors before a mechanistic differentiation takes place. Using a peptide array approach, we first identified peptides inhibiting the predominantly amorphous aggregation of a molten globular, aggregation-prone protein, a thermolabile mutant of the Axin tumor suppressor. A series of optimization steps revealed that the peptides activity did not depend on their sequences but rather on their molecular determinants. The key properties that made a peptide active were a composition of 20-30% flexible, 30-40% aliphatic and 20-30% aromatic residues, a hydrophobicity/hydrophilicity ratio close to 1 and an even distribution of residues of different nature throughout the sequence. Remarkably, the optimized peptides also suppressed fibrillation of Tau, a disordered protein that forms amyloids in Alzheimers disease, and entirely unrelated to Axin. Our compounds thus target early aggregation stages, independent of the aggregation mechanism, inhibiting both amorphous and amyloid aggregation. Such cross-mechanistic, multi-targeting aggregation inhibitors may be attractive lead compounds against multiple protein aggregation diseases.

biochemistry↗