Development and in vitro effects of thiolated chitosan nanoparticles for the sustained delivery of inflammation suppressing bioactive peptide

Marine food derived compounds are highly studied as therapeutics due to their biological activity. Moreover, due to high mucoadhesivity and solubility, chitosan (CS) is widely used as a natural polymeric carrier for the delivery of peptides, proteins, and other nutraceutical compounds. Peptides can be made resistant to protease cleavage, exhibit stability at the target site, and have increased in vivo half-life time when conjugated with polymeric nanoformulations. In this study, modified thiolated chitosan (TCS) was developed which was used for the preparation of marine crab body muscle derived anti-inflammatory peptide (ESPVL) loaded nanoparticles (Pep-TCSNPs). The uniform size nanoparticles showed sustained release of peptide till 30th hr and further constant release rate, improved thermal stability while the same also showed non-cytotoxic effects till 100 μM concentration. Moreover, the nanoformulations also suppressed the production of nitrite as well as reactive oxygen species levels upon lipopolysaccharide (LPS) stimulation in L929 cells. The Pep-TCSNPs at 100 μM concentration showed greater suppression of pro-inflammatory cytokines as well as phosphorylated-p65 (p-p65) levels and efficient cellular uptake in vitro. Furthermore, docking results revealed conventional hydrogen and pi-alkyl bonds between the peptide ligand as well as receptor proteins which suggested enhanced stability and potent inflammation suppressing activity of Pep-TCSNPs in a sustained manner.