Mapping of Methyl Epitopes of a Peptide-Drug with Its Receptor by 2D STDD-Methyl TROSY NMR Spectroscopy.

The current trend in the biopharmaceutical market has boosted the development and production of biological drugs with high efficacy and fidelity for receptor binding. While high-resolution structural insights into binding epitopes of the receptor are indispensable for better therapeutic design, it is tedious and costly. In this work, we develop a protocol by integrating two well-known NMR-based solution-state methods. Saturation transfer double-difference with methyl-TROSY (STDD-Methyl TROSY NMR) was used to probe methyl binding epitopes of the ligand in a label-free environment. This study was carried out with Human insulin as a model peptide drug, with the insulin growth factor receptor (IGFR), which is an off-target receptor for insulin. Methyl epitopes identified from STDD-Methyl TROSY NMR spectroscopy were validated through the HADDOCK platform to generate a drug-receptor model. Since this method can be applied at natural abundance, it has the potential to screen a large set of peptide-drug interactions for optimum receptor binding. Thus, we propose STDD-Methyl TROSY NMR spectroscopy as a technique for rapid screening of biologics for the development of optimized biopharmaceutics.

A combinatorial study of experimental analysis and mathematical modeling: How do chitosan nanoparticles deliver therapeutics into cells?

Chitosan nanosystems have been widely explored to deliver therapeutic into cells. The cationic nature of the polymer facilitates its entry into the cell via the negatively charged lipid bilayer. Though the interaction is feasible for successful payload delivery, very little is known about the mechanistic aspects and kinetics of interaction of chitosan nanoparticles (Chnps) with the cellular bilayer membrane. Moreover, the precise mechanism of delivery of therapeutic agents by the Chnps is unknown. The polymerbilayer membrane is anticipated to play a crucial role in deciding its ultimate intracellular fate, while delivering its therapeutic payload. Here, we have made an attempt to understand the interaction of Chnps with the cellular membrane for delivering payload, through experimental analysis and predictive mathematical modeling. We observed that the positively charged, mucoadhesive Chnps lack specificity towards a particular cell type, but are rather successful in the intracellular delivery of nucleic acids.

Role of proton balance in formation of self-assembled chitosan nanoparticles.

Researchers have explored the ability of chitosan to form nanoparticles, to suit varying applications, ranging from wound-healing to gene delivery. Ionic gelation is a widely used method for formulating chitosan nanoparticles, where self-assembly plays a crucial role. This self-assembly is initially promoted by hydrophilic-hydrophobic parity amongst individual chitosan residues, along with electrostatic and Van der Waals interactions with the cross-linker. However, until now the intrinsic ability of chitosan to self-assemble is not widely studied; hence, we investigate the self-assembly of chitosan, based on proton balance between its protonated and deprotonated residues, to promote facile nanoparticle synthesis. This is one of the first reports that highlights subtle but critical influence of proton balance in the chitosan polymer on the formation of chitosan nanoparticles.

Potential Gene Therapy Towards Treating Neurodegenerative Disea ses Employing Polymeric Nanosystems.

BACKGROUND: Recent integrated approaches involving nanotechnology and gene therapy have accelerated development of efficient drug delivery to the central nervous system (CNS). Neurodegenerative disorders are closely associated with genetic inheritance and mutation. MATERIALS: Nanotechnology has allowed effective engineering of various such polymeric structures. Moreover, availability of a wide array of polymeric materials has enabled fabrication of biocompatible and biodegradable delivery vehicles. Our manuscript focuses on the ideal features and properties of polymeric nanoparticles that have enabled successful gene therapy for neurodegenerative disorders, as well as the challenges that are posing difficulties in their practical application. We have highlighted these aspects through examples of polymeric nanoparticles that have exhibited therapeutic promise in the treatment of neurological disorders and mutations. METHODS: Complete cure of these diseases is a challenging task and gene therapy appears as a realistic approach for their treatment. Gene therapy allows effective replacement or suppression of faulty genes, thereby increasing chances for neuron survival and repair. However, successful delivery of naked genetic material to CNS faces severe obstacles due to possible degradation and restricted transportation of these biological entities across the blood brain barrier (BBB). Structurally, the BBB is composed of several tight junctions, making the membrane highly selective towards the entry of molecules. CONCLUSION: In order to target BBB for treating neurodegenerative diseases, it is essential to develop a tailor-made system that may not only cross this barrier, but also effectively modulate the expression of disease-causing genes. Stabilization of therapeutic genes and their effective, targeted delivery may be possible using polymeric nanoparticles as carriers.