8-Anilino-1-naphthalenesulfonic acid

Cysteamine functionalized MoS2 quantum dots inhibit amyloid aggregation.[Pubmed:30716371]

Int J Biol Macromol. 2019 May 1;128:870-876.

In this study, cysteamine-functionalized molybdenum disulfide quantum dots (MoS2 QDs) were synthesized by a one-pot hydrothermal method. A range of techniques including of Thioflavin T and 8-Anilino-1-naphthalenesulfonic acid fluorescence assays, circular dichroism, and transmission electron microscope have been employed to determination the efficacy of MoS2 QDs on the inhibition/reversion of fibrillation and hindering cytotoxicity induced by protofibrils and amyloid fibrils of bovine serum albumin (BSA). Results demonstrated that MoS2 QDs could effectively inhibit the fibrillogenesis and destabilize preformed fibrils of BSA in a concentration-dependent manner. Cytotoxicity protection and imagine on Hela cells was investigated using the methyl thiazolyl tetrazolium (MTT) assay. It was found that MoS2 QDs not only has good biocompatibility, low toxicity and good cell penetration, but also could effectively decrease the cytotoxicity caused by the formed fibrils of BSA. The results obtained in this work suggested the potential biological application of MoS2 QDs in therapeutics and provided new insight into the design of multifunctional nanomaterials for amyloid-related diseases.

Effects of Ser47-Point Mutation on Conformation Structure and Allergenicity of the Allergen of Der p 2, a Major House Dust Mite Allergen.[Pubmed:30479083]

Allergy Asthma Immunol Res. 2019 Jan;11(1):129-142.

PURPOSE: Hypoallergenic recombinant Der p 2 has been produced by various genetic manipulations, but mutation of a naturally polymorphic amino acid residue known to affect IgE binding has not been studied. This study aimed to determine the effect of a point mutation (S47W) of residue 47 of Der p 2 on its structure and immunoglobulin (Ig) E binding. Its ability to induce pro-inflammatory responses and to induce blocking IgG antibody was also determined. METHODS: S47 of recombinant Der p 2.0110, one of the predominant variants in Bangkok, was mutated to W (S47W). S47W secreted from Pichia pastoris was examined for secondary structure and for the formation of a hydrophobic cavity by 8-Anilino-1-naphthalenesulfonic acid (ANS) staining. Monoclonal and human IgE-antibody binding was determined by enzyme-linked immunosorbent assay. Allergen-induced degranulation by human epsilon receptor expressed-rat basophil was determined. Stimulation of the pro-inflammatory cytokine interleukin (IL)-8 release from human bronchial epithelial (BEAS2B) cells and inhibition of IgE binding to the wild type allergen by S47W-induced IgG were determined. RESULTS: S47W reduced secondary structure and failed to bind the hydrophobic ANS ligand as well as a monoclonal antibody known to be dependent on the nature of the side chain of residue 114 in an adjacent loop. It could also not stimulate IL-8 release from BEAS2B cells. IgE from house dust mite (HDM)-allergic Thais bound S47W with 100-fold weaker avidity, whereas IgE of HDM-allergic Australians did not. S47W still induced basophil degranulation, although requiring higher concentrations for some subjects. Anti-S47W antiserum-immunized mice blocked the binding of human IgE to wild type Der p 2. CONCLUSIONS: The mutant S47W had altered structure and reduced ability to stimulate pro-inflammatory responses and to bind IgE, but retained its ability to induce blocking antibodies. It thus represents a hypoallergen produced by a single mutation of a non-solvent-accessible amino acid.

Proline functionalized gold nanoparticles modulates lysozyme fibrillation.[Pubmed:30476794]

Colloids Surf B Biointerfaces. 2019 Feb 1;174:401-408.

Amyloid fibrils are the hallmarks of neurodegenerative diseases like Alzheimer's, Parkinson's and other proteopathies. Inhibition of fibrillation is a potential strategy to check the progress of amyloid associated diseases and further allied deterioration. In this study, we have synthesized proline functionalized gold nanoparticles (Pro-AuNPs) and scrutinized its antifibrillation property towards Hen Egg White Lysozyme (HEWL) aggregation. Pro-AuNPs were characterized using various biophysical methods like ultraviolet-visible spectroscopy, fourier transform infra-red spectroscopy, zeta potential measurement, dynamic light scattering and transmission electron microscopy. The effect of Pro-AuNPs on HEWL fibrillation was analyzed employing thioflavin T (ThT) and 8-Anilino-1-naphthalenesulfonic acid (ANS) assays. The kinetics of HEWL exhibited a typical sigmoidal nature of protein aggregation and was fitted to Boltzmann model. HEWL in the presence of bare gold nanoparticles (bAuNPs) exhibited similar aggregation kinetics as HEWL alone. However, HEWL fibrillation substantially reduced upon co-incubation with proline and Pro-AuNPs, and two slightly different intermediate species were formed with these two systems as predicted by CD spectroscopy. TEM images also supported the above observation displaying different morphological states of HEWL aggregates in the presence of proline and Pro-AuNPs. Using computational methods, the nature of interaction of HEWL and proline was found to be hydrogen bonding and hydrophobic interaction in multiple amyloidogenic regions. These interactions inhibited the formation of prefibrils (beta-sheet rich intermediates) and also found to disintegrate fibrils. Furthermore, HEWL-Pro-AuNPs system resulted HEWL adsorption through hydrophobic patches, which blocked the intermolecular beta-sheet formation. The present study successfully established Pro-AuNPs as a potential inhibitor of HEWL aggregation.