αB-Crystallin Peptide Fused with Elastin-like Polypeptide: Intracellular Activity in Retinal Pigment Epithelial Cells Challenged with Oxidative Stress.

BACKGROUND: Oxidative stress-induced retinal degeneration is among the main contributing factors of serious ocular pathologies that can lead to irreversible blindness. αB-crystallin (cry) is an abundant component of the visual pathway in the vitreous humor, which modulates protein and cellular homeostasis. Within this protein exists a 20 amino acid fragment (mini-cry) with both chaperone and antiapoptotic activity. This study fuses this mini-cry peptide to two temperature-sensitive elastin-like polypeptides (ELP) with the goal of prolonging its activity in the retina. METHODS: The biophysical properties and chaperone activity of cry-ELPs were confirmed by mass spectrometry, cloud-point determination, and dynamic light scattering 'DLS'. For the first time, this work compares a simpler ELP architecture, cry-V96, with a previously reported ELP diblock copolymer, cry-SI. Their relative mechanisms of cellular uptake and antiapoptotic potential were tested using retinal pigment epithelial cells (ARPE-19). Oxidative stress was induced with H2O2 and comparative internalization of both cry-ELPs was made using 2D and 3D culture models. We also explored the role of lysosomal membrane permeabilization by confocal microscopy. RESULTS: The results indicated successful ELP fusion, cellular association with both 2D and 3D cultures, which were enhanced by oxidative stress. Both constructs suppressed apoptotic signaling (cleaved caspase-3); however, cry-V96 exhibited greater lysosomal escape. CONCLUSIONS: ELP architecture is a critical factor to optimize delivery of therapeutic peptides, such as the anti-apoptotic mini-cry peptide; furthermore, the protection of mini-cry via ELPs is enhanced by lysosomal membrane permeabilization.

A Tenofovir-Loaded Glycyrrhetinic Acid-Modified Cationic Liposome for Targeted Therapy of Hepatitis B Virus.

Tenofovir (TFV), an acyclic nucleoside analog, exhibits potent anti-HBV activity. However, poor bioavailability, nephrotoxicity and bone toxicity limit its further clinical application. In this work, a novel tenofovir-loaded glycyrrhetinic acidmodified cationic liposome (TGCL) was prepared for targeted therapy of HBV. The TGCL had an average particle size of 107.39 ± 1.21 nm and an entrapment efficiency of 89.83 ± 2.70% with a positive zeta potential of 37.63 ± 1.22 mV. The results of in vitro indicated that the inhibitory effects on HBsAg, HBeAg and HBV cccDNA of TGCL in HepG2.2.15 cells were significantly better than that of free TFV and non-targeted cationic liposome. In the DHBV-infected duck model, TGCL showed remarkably suppression on DHBV DNA than that of free TFV. Overall, TGCL is a promising formulation of TFV for targeted therapy of HBV.