Advances in the regulation of natural polysaccharides on human health: The role of apoptosis/autophagy pathway

Nanoplastics induces oxidative stress and triggers lysosome-associated immune-defensive cell death in the earthworm Eisenia fetida

Nanoplastics (NPs) are increasingly perceived as an emerging threat to terrestrial environments, but the adverse impacts of NPs on soil fauna and the mechanisms behind these negative outcomes remain elusive. Here, a risk assessment of NPs was conducted on model organism (earthworm) from tissue to cell. Using palladium-doped polystyrene NPs, we quantitatively measured nanoplastic accumulation in earthworm and investigated its toxic effects by combining physiological assessment with RNA-Seq transcriptomic analyses. After a 42-day exposure, earthworm accumulated up to 15.9 and 143.3 mg kg-1 of NPs for the low (0.3 mg kg-1) and high (3 mg kg-1) dose groups, respectively. NPs retention led to the decrease of antioxidant enzyme activity and the accumulation of reactive oxygen species (O2- and H2O2), which reduced growth rate by 21.3 %-50.8 % and caused pathological abnormalities. These adverse effects were enhanced by the positively charged NPs. Furthermore, we observed that irrespective of surface charge, after 2 h of exposure, NPs were gradually internalized by earthworm coelomocytes (∼0.12 μg per cell) and mainly amassed at lysosomes. Those agglomerations stimulated lysosomal membranes to lose stability and even rupture, resulting in impeded autophagy process and cellular clearance, and eventually coelomocyte death. In comparison with negatively charged nanoplastics, the positively charged NPs exerted 83 % higher cytotoxicity. Our findings provide a better understanding of how NPs posed harmful effects on soil fauna and have important implications for evaluating the ecological risk of NPs.

Therapeutic Prospects of Polysaccharides for Ovarian Cancer

Ovarian cancer (OC) is ranked as the leading cause of death among cancers of the female reproductive tract. First-line platinum treatment faces the severe challenges associated with the patient relapse and poor prognosis. Thus, it is imperative to develop natural antitumor drugs for OC with high efficacy. Natural polysaccharides have significant biological activities and antitumor effects. Our work has demonstrated that polysaccharides play key roles by inhibiting the cell proliferation and growth, regulating the tumor cell cycle, inducing apoptosis, suppressing the tumor cell migration and invasion, improving the immunomodulatory activities, and enhancing the efficacy of chemotherapy (cisplatin) in OC, which provide powerful evidence for the application of polysaccharides as novel anticancer agents, supplementary remedies, and adjunct therapeutic agents alone or in combination with cisplatin for preventing and treating the OC.

Biosynthetic cell membrane vesicles to enhance TRAIL-mediated apoptosis driven by photo-triggered oxidative stress

Due to the tumor-specificity and limited side effects, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) shows great potential in cancer treatments. However, the short half-life of TRAIL protein and the poor...