ABSTRACT
The development of imaging agents for inâ vivo detection of alpha-synuclein (α-syn) pathologies faces several challenges. A major gap in the field is the lack of diverse molecular scaffolds with high affinity and selectivity to α-syn fibrils for inâ vitro screening assays. Better inâ vitro scaffolds can instruct the discovery of better inâ vivo agents. We report the rational design, synthesis, and inâ vitro evaluation of a series of novel 1-indanone and 1,3-indandione derivatives from a Structure-Activity Relationship (SAR) study centered on some existing α-syn fibril binding ligands. Our results from fibril saturation binding experiments show that two of the lead candidates compounds 8 and 32 bind α-syn fibrils with binding constants (Kd ) of 9.0 and 18.8â nM, respectively, and selectivity of greater than 10× for α-syn fibrils compared with amyloid-ß (Aß) and tau fibrils. Our results demonstrate that the lead ligands avidly label all forms of α-syn on PD brain tissue sections, but only the dense core of senile plaques in AD brain tissue, respectively. These results are corroborated by ligand-antibody colocalization data from Syn211, which shows immunoreactivity toward all forms of α-syn aggregates, and Syn303, which displays preferential reactivity toward mature Lewy pathology. Our results reveal that 1-indanone derivatives have desirable properties for the biological evaluation of α-synucleinopathies.
Subject(s)
Alzheimer Disease/drug therapy , Indans/pharmacology , Neuroprotective Agents/pharmacology , alpha-Synuclein/antagonists & inhibitors , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Dose-Response Relationship, Drug , Drug Design , Humans , Indans/chemical synthesis , Indans/chemistry , Ligands , Molecular Structure , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , Protein Aggregates/drug effects , Protein Folding/drug effects , Structure-Activity Relationship , alpha-Synuclein/metabolismABSTRACT
Biodegradable polymer-based drug-eluting implants offer many advantages such as predictable drug release kinetics, safety, and acceptable drug loading under ambient conditions. Herein, we describe fabrication and evaluation of antibiotic loaded scaffolds for localized delivery and tissue engineering applications. PDLLA particles entrapping gentamycin were formulated using solvent evaporation method and used for scaffold fabrication. Optimization of formulation parameters such as pH of the internal aqueous phase and combination of excipients like glycerol, polyvinyl alcohol (PVA) resulted in high entrapment efficiencies up to 96% of gentamicin in particles with drug load of 16-18µg/mg of polymer particles. These microparticles were fused in presence of methanol at ambient temperatures to form scaffolds of different geometry having reasonable mechanical strength. Porosity of these scaffolds was found to be more than 80%. Antibiotic released from the scaffolds was found to be bioactive as tested against Staphylococcus aureus and the release pattern was biphasic over a period of one week. The scaffolds were found to be non-toxic to murine fibroblasts cultures in vitro as well as to mice upon subcutaneous implantation. This method provides a novel and easy way of fabricating antibiotic loaded polymer scaffolds for varieties of applications.
Subject(s)
Absorbable Implants , Biodegradable Plastics/chemistry , Drug Implants/chemistry , Gentamicins/administration & dosage , Lactic Acid/chemistry , Polyglycolic Acid/chemistry , Temperature , Tissue Scaffolds/chemistry , Absorbable Implants/adverse effects , Animals , Biodegradable Plastics/adverse effects , Cell Survival/drug effects , Cells, Cultured , Drug Implants/administration & dosage , Drug Implants/pharmacokinetics , Drug Liberation , Fibroblasts/drug effects , Gentamicins/pharmacokinetics , Gentamicins/pharmacology , Glycerol/chemistry , Lactic Acid/adverse effects , Mice , Microbial Sensitivity Tests , Particle Size , Polyesters/chemistry , Polyglycolic Acid/adverse effects , Polylactic Acid-Polyglycolic Acid Copolymer , Polyvinyl Alcohol/chemistry , Tissue Scaffolds/adverse effectsABSTRACT
A series of tryptophan-based peptides W1a, b-W4a, b, with diverse architectures were designed and synthesized. These tryptophan containing peptides can self-assemble to spherical particle. This self-assembled system was demonstrated to encapsulate rhodamine B and penetrate the cell membrane.
Subject(s)
Dendrimers/chemistry , Drug Carriers/chemistry , Peptides/chemistry , Rhodamines/administration & dosage , Tryptophan/chemistry , Animals , Cell Line , MiceABSTRACT
INTRODUCTION: Gymnema sylvestre is an important anti-diabetic medicinal plant, hence it is necessary to study the effective extraction of its active medicinal components. OBJECTIVE: To develop an efficient ultrasound-assisted extraction method for anti-diabetic gymnemic acids from Gymnema sylvestre leaves and measure their effect on insulin-producing RINm-5 F ß cells. METHODS: Box-Behnken's design and response surface methodology was applied to the ultrasound-assisted extraction of gymnemic acids from Gymnema sylvestre leaves. Analysis of gymnemic acids was carried out by high-performance thin-layer chromatography by converting total gymnemic acids into gymnemagenin by alkali hydrolysis. Effects of extracts on insulin production were tested on cultured, insulin-producing RINm-5 F ß cell lines. RESULTS: The point prediction tool of the design expert software predicted 397.9 mg gymnemic acids per gram of the defatted G. sylvestre leaves using ultrasound-assisted extraction, with ethanol at 60 °C for 30 min. The predicted condition shows 93.34% validity under experimental conditions. The ultrasound-assisted extract caused up to about four times more insulin production from RINm-5 F ß cells than extracts obtained from Soxhlet extraction. CONCLUSIONS: Response surface methodology was successfully used to improve the extraction of gymnemic acids from G. sylvestre leaves. The ultrasound-assisted extraction process may be a better alternative to prepare such herbal extracts because it saves time and may prevent excess degradation of the target analytes.
Subject(s)
Alkaloids/pharmacology , Gymnema sylvestre/chemistry , Plant Extracts/pharmacology , Saponins/pharmacology , Triterpenes/pharmacology , Alkaloids/chemistry , Alkaloids/isolation & purification , Cell Line , Gymnema sylvestre/ultrastructure , Hydrolysis , Insulin/metabolism , Microscopy, Electron, Scanning , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Plant Leaves/ultrastructure , Plants, Medicinal , Saponins/chemistry , Saponins/isolation & purification , Triterpenes/chemistry , Triterpenes/isolation & purification , UltrasonicsABSTRACT
We report here a novel surfactant mediated fusion of polylactide particles into scaffoldlike structures at room temperature. In the presence of ethanol, evenly spread surfactant coated polylactide particles fused immediately into membranelike structures. Polymer scaffolds of the desired shape and size could be fabricated from polylactide particles using this fusion process. Desorption of surfactant molecules from the surface of the particles during ethanol treatment and the degree of solubility of the polymer in alcohol were found to be the main reasons for the fusion of particles into a scaffold at room temperature. TGA and DSC studies of the polylactide particles showed that the particles were stable at room temperature, and FTIR studies showed that there was no change in characteristics of the polymer after the fusion of particles into a scaffold-type structure. These scaffolds supported three-dimensional growth of animal cells in vitro and release model protein in a sustained manner for a long period of time. In an experimental animal wound model, the polylactide membranes showed faster wound closure, indicating its use as a passive dressing material. This polymer particle fusion process thus provides a novel method of scaffold fabrication for various biomedical applications.