Preparation of amentoflavone-loaded DSPE-PEG2000 micelles with improved bioavailability and in vitro antitumor efficacy.

To overcome the poor aqueous solubility and enhance the anticancer effects of amentoflavone (AF), a nontoxic and biodegradable amphiphilic copolymer, poly(ethyleneglycol)-distearoylphosphatidylethanolamine (DSPE-PEG2000 ), was introduced to prepare AF micelles using the thin-film hydration method. Amentoflavone was successfully encapsulated into the core, achieving an encapsulation efficiency of 98.80 ± 0.24% and a drug loading efficiency of 2.96 ± 0.12%. The resulting micelles exhibited a spherical shape with a particle size of approximately 25.99 nm. The solubility of AF was significant improved by 412-fold, and cumulative drug release studies showed that AF release was much faster from the micelles compared with the free drug. The release of AF was sustained over time and followed a degradation-based kinetic model, similar to polymeric systems. After oral administration, the AF-loaded micelles demonstrated an enhanced oral bioavailability, which was 3.79 times higher than that of free AF. In vitro evaluations of the micelles' antitumor effects revealed a significantly greater efficacy compared with free AF. These findings highlight the tremendous potential of DSPE-PEG2000 micelles as a drug delivery carrier for improving the solubility and therapeutic efficacy of AF.

Calpain-2 Facilitates Autophagic/Lysosomal Defects and Apoptosis in ARPE-19 Cells and Rats Induced by Exosomes from RPE Cells under NaIO3 Stimulation.

Although accumulated evidence supports the notion that calpain contributes to eye disease, the mechanisms by which calpain promotes RPE injury are not defined. The present study is aimed at investigating whether the effect of NaIO3-exos (exosomes derived from RPE cells under NaIO3 stimulation) on the dysfunction of the autophagy-lysosomal pathway (ALP) and apoptosis is based on its regulation of calpain activation in ARPE-19 cells and rats. The results showed that calpain-2 activation, ALP dysfunction, and apoptosis were induced by NaIO3-exos in ARPE-19 cells. NaIO3-exo significantly increased autophagic substrates by activating lysosomal dysfunction. ALP dysfunction and apoptosis in vitro could be eliminated by knocking down calpain-2 (si-C2) or the inhibitor calpain-2-IN-1. Further studies indicated that NaIO3-exo enhanced calpain-2 expression, ALP dysfunction, apoptosis, and retinal damage in rats. In summary, these results demonstrate for the first time that calpain-2 is one of the key players in the NaIO3-exo-mediated ALP dysfunction, apoptosis, and retinal damage and identify calpain-2 as a promising target for therapies aimed at age-related macular degeneration (AMD).