The host nucleocytoplasmic trafficking system is often hijacked by viruses to accomplish their replication and to suppress the host immune response. Viruses encode many factors that interact with the host nuclear transport receptors (NTRs) and the nucleoporins of the nuclear pore complex (NPC) to access the host nucleus. In this review, we discuss the viral factors and the host factors involved in the nuclear import and export of viral components. As nucleocytoplasmic shuttling is vital for the replication of many viruses, we also review several drugs that target the host nuclear transport machinery and discuss their feasibility for use in antiviral treatment.
Background and Aim: Natural products are currently widely used as alternative treatments for liver disease. The study aimed to determine the hepatoprotective effect of crude polysaccharides extracted from Ganoderma lucidum against liver injury induced by carbon tetrachloride (CCl4).
Materials and Methods: Twenty-four male BALB/C mice were randomly divided into six groups. Serum and liver samples were taken on day 10 after G. lucidum administration. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) were measured using enzyme-linked immunosorbent assays, and the histology of the liver was evaluated using light microscopy.
Results: G. lucidum extract significantly decreased the levels of ALT, AST, and MDA and significantly increased the levels of SOD and CAT. In the histological evaluation, the liver tissue of CCl4-treated mice exhibited hydropic degeneration, necrosis, and sinusoidal dilatation. G. lucidum extract administration improved this liver tissue histopathology.
Conclusion: Crude polysaccharides extracted from G. lucidum showed a hepatoprotective effect, regenerating damaged liver tissue.
Small extracellular vesicles (sEVs) play a crucial role in local and distant cell communication. The intrinsic properties of sEVs make them compatible biomaterials for drug delivery, vaccines, and theranostic nanoparticles. Although sEV proteomics have been robustly studied, a direct instantaneous assessment of sEV structure dynamics remains difficult. Here, we use the high‐speed atomic force microscopy (HS‐AFM) to evaluate nanotopological changes of sEVs with respect to different physicochemical stresses including thermal stress, pH, and osmotic stress. The sEV structure is severely altered at high‐temperature, high‐pH, or hypertonic conditions. Surprisingly, the spherical shape of the sEVs is maintained in acidic or hypotonic environments. Real‐time observation by HS‐AFM imaging reveals an irreversible structural change in the sEVs during transition of pH or osmolarity. HS‐AFM imaging provides both qualitative and quantitative data at high spatiotemporal resolution (nanoscopic and millisecond levels). In summary, our study demonstrates the feasibility of HS‐AFM for structural characterization and assessment of nanoparticles.
Anti-spike neutralizing antibodies (S NAbs) have been developed for prevention and treatment against COVID-19. The nanoscopic characterization of the dynamic interaction between spike proteins and S NAbs remains difficult. By using high-speed atomic force microscopy (HS-AFM), we elucidate the molecular property of an S NAb and its interaction with spike proteins. The S NAb appeared as monomers with a Y conformation at low density and formed hexameric oligomers at high density. The dynamic S NAb−spike protein interaction at RBD induces neither RBD opening nor S1 subunit shedding. Furthermore, the interaction was stable at endosomal pH. These findings indicated that the S NAb could have a negligible risk of antibody-dependent enhancement. Dynamic movement of spike proteins on small extracellular vesicles (S sEV) resembled that on SARS-CoV-2. The sensitivity of variant S sEVs to S NAb could be evaluated using HS-AFM. Altogether, we demonstrate a nanoscopic assessment platform for evaluating the binding property of S NAbs.
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