Pyrazolamide derivatives inhibit α-Synuclein aggregation, disaggregate preformed fibers, and reduce inclusion formation in neuron cells

Hydroxycinnamic acids mediated modulation of α-Synuclein fibrillation: Biophysical insights

The fibrillation of α-synuclein (α-Syn) is considered a major contributor to Parkinson's disease (PD). Recent therapeutic measures have focused on inhibiting the fibrillation of α-Syn using various small molecules. We report here the effects of two different hydroxycinnamic acids; chlorogenic acid and sinapic acid on α-Syn fibrillation and have also discussed the mechanistic insights into their mode of modulation. The fluorescence spectroscopy shows that the two hydroxycinnamic acids bind with α-Syn with moderate affinity. Molecular docking studies provide a detailed insights into binding at the residue level and isothermal titration calorimetry reveals specific interactions, like hydrogen bonding, hydrophobic interactions, and van der Waals forces involved in the binding process. Fibrillation kinetics and transmission microscopic studies demonstrated that both chlorogenic acid and sinapic acid attenuate α-Syn fibrillation in a concentration dependent manner. Circular dichroism spectroscopy shows that these compounds bind with α-Syn and delay its structural transition in β-sheet containing fibrillar structures. Both the compounds are also effective even if added after the onset of fibrillation and the fibrillar species formed in the presence of these acids are unable to induce secondary nucleation in monomeric α-Syn. Such kind of structural and mechanistic insights are extremely crucial for designing therapeutic intervention in PD and other neurodegenerative diseases.

Novel 4-triazole phenyl amide (4-TPA) molecules: Potent promoters of α-synuclein fibril disassembly

Parkinson's disease profoundly compromises patients' daily lives, and the disassembly of α-synuclein aggregates, a primary pathological factor, represents a promising therapeutic approach. In this study, we conducted a systematic screening and optimization process to identify the novel scaffold B37, a 4-triazolyl-phenylamine derivative, exhibiting a potent disassembly activity of 1.1 μM against α-synuclein preformed fibrils. Notably, B37 demonstrated significant neuroprotective effects, ameliorated autophagic dysfunction induced by preformed fibrils, mitigated oxidative stress, and restored the co-localization of preformed fibrils with lysosomes. Transmission electron microscopy corroborated its in vitro disassembly function. Pharmacokinetic profiling revealed favorable parameters with a receptible blood-brain barrier permeability. B37 emerges as a promising lead compound for further optimization, aiming to develop a highly effective agent targeting the disassembly of α-synuclein aggregates to treat neurodegenerative diseases like Parkinson's disease.

In vitro inhibition of α-Synuclein aggregation and disaggregation of preformed fibers by polyphenol hybrids with 2-conjugated benzothiazole

The misfolding and aggregation of α-Syn play a pivotal role in connecting diverse pathological pathways in Parkinson's disease (PD). Preserving α-Syn proteostasis and functionality by inhibiting its aggregation or disaggregating existing aggregates using suitable inhibitors represents a promising strategy for PD prevention and treatment. In this study, a series of benzothiazole-polyphenol hybrids was designed and synthesized. Three identified compounds exhibited notable inhibitory activities against α-Syn aggregation in vitro, with IC50 values in the low micromolar range. These inhibitors demonstrated sustained inhibitory effects throughout the entire aggregation process, stabilizing α-Syn proteostasis conformation. Moreover, the compounds effectively disintegrated preformed α-Syn oligomers and fibers, potentially by binding to specific domains within the fibers, inducing fibril instability, collapse, and ultimately resulting in smaller-sized aggregates and monomers. These findings offer valuable insights into the therapeutic potential of polyphenol hybrids with 2-conjugated benzothiazole targeting α-Syn aggregation in the treatment of PD.