Probing cell membrane integrity using a histone-targeting protein nanocage displaying precisely positioned fluorophores

Plasmalogens Reversed Oxidative Stress and Inflammatory Response Exacerbated by Damage to Cell Membrane Properties in Acute Liver Injury

BACKGROUND

In acute liver injury (ALI), cell membrane damage could induce an inflammatory response and oxidative stress. As a membrane glycerophospholipid, plasmalogens (PLS) are crucial in regulating the cell membrane properties and exhibit beneficial effects in various liver diseases. However, the specific regulatory effects of PLS in the ALI remain unknown.

METHODS

We utilized CCl4 to induce ALI in AML12 hepatocytes and C57BL/6J mice and examined oxidative stress indicators and inflammatory cytokine levels. Our study further validated the effect of PLS on cell membrane integrity by Lactate Dehydrogenase (LDH) release assay and Dil/Calcein assay, and molecular dynamics (MD) simulations were employed to elucidate the molecular mechanisms by which PLS affected cell membranes.

RESULTS

PLS attenuated hepatocyte damage both in vivo and in vitro. Moreover, PLS increased levels of SOD, GSH, and CAT and inhibited the production of malondialdehyde. PLS succeeded in decreasing proinflammatory cytokines (TNF-α, IL-1β, and IL-6) while increasing anti-inflammatory cytokines (IL-10). Furthermore, PLS effectively maintained the cell membrane integrity. The MD simulations well explained the molecular mechanisms: a high level of PLS modulated the cell membrane properties, enabling them to be more flexible, elastic, and less prone to rupture.

CONCLUSIONS

Our study illustrated the effect and molecular mechanisms of PLS against ALI, potentially broadening its application in liver diseases.

Effects of Individual Amino Acids on the Blood Circulation of Biosynthetic Protein Nanocages: Toward Guidance on Surface Engineering

Protein nanocages (PNCs) hold great promise for developing multifunctional nanomedicines. Long blood circulation is a key requirement of PNCs for most in vivo application scenarios. In addition to the classical PEGylation strategy, short peptides with a specific sequence screened via phage display are also very effective in prolonging the blood half-life (t1/2 ) of PNCs. However, there is a lack of knowledge on how individual amino acids affect the circulation of PNCs. Here the effects of the 20 proteinogenic amino acids in the form of an X3 or X5 tag (X represents an amino acid) are explored on the pharmacokinetics of PNCs, which lead to the formation of a heatmap illustrating the extent of t1/2 prolongation by each proteinogenic amino acid. Significantly, oligo-lysine and oligo-arginine can effectively prolong the t1/2 of strongly negatively charged PNCs through charge neutralization, while oligo-cysteine can also do so, but via a different mechanism, mediating the covalent binding of PNCs with plasma albumin as a stealth material. These findings are extendible and offer guidance for surface-engineering biosynthetic PNCs and other nanoparticles.

Targeted delivery of Dbait by an artificial extracellular vesicle for improved radiotherapy sensitivity of esophageal cancer

Intensification of radiotherapy has been shown to be an effective way for improving the therapeutic efficacy of radiation sensitive malignancies such as esophageal cancer (EC). The application of DNA Bait (Dbait), a type of DNA repair inhibitor, is an emerging strategy for radiosensitization. In this study, a Eca-109 cancerous cytomembrane-cloaked biomimetic drug delivery system (DDS), CMEC-Dbait, was designed and successfully fabricated, for targeted delivery of Dbait. Our systematic evaluation demonstrated that the ingenious artificial gastrointestinal extracellular vesicle owns neat spherical structure, proper particle size (154.6±5.5 nm) and surface charge (2.6±0.3 mV), favourable biocompatibility and immunocompatibility, being conducive to in vivo drug delivery. Besides, Eca-109 cytomembrane coating endowed CMEC-Dbait with effective targeting ability to homologous EC cells. Owing to these advantages, the biomimetic DDS was proved to be a potent radiosensitizer in vitro, indicated by remarkably reduced cell viability and enhanced cellular apoptosis by the combination therapy of radiation and CMEC-Dbait. The result was validated in vivo using mouse xenograft models of EC, the results illustrated that radiotherapy plus CMEC-Dbait significantly suppressed tumor growth and prolonged survival of tumor bearing mice. Western blotting results showed that CMEC-Dbait can significantly inhibit DNA damage repair signaling pathways by simulating DNA double-strand breaks both in and ex vivo. In conclusion, the versatile biomimetic CMEC-Dbait was characterized of low toxicity, excellent biocompatibility and satisfactory drug delivery efficiency, which is confirmed to be an ideal radiosensitizer for homologous cancer and merits further investigation in both pre-clinical and clinical studies.