Effective mRNA Inhibition in PANC-1 Cells in Vitro Mediated via an mPEG-SeSe-PEI Delivery System

The clinical progress and challenges of mRNA vaccines

Owing to the breakthroughs in the prevention and control of the COVID-19 pandemic, messenger RNA (mRNA)-based vaccines have emerged as promising alternatives to conventional vaccine approaches for infectious disease prevention and anticancer treatments. Advantages of mRNA vaccines include flexibility in designing and manipulating antigens of interest, scalability in rapid response to new variants, ability to induce both humoral and cell-mediated immune responses, and ease of industrialization. This review article presents the latest advances and innovations in mRNA-based vaccines and their clinical translations in the prevention and treatment of infectious diseases or cancers. We also highlight various nanoparticle delivery platforms that contribute to their success in clinical translation. Current challenges related to mRNA immunogenicity, stability, and in vivo delivery and the strategies for addressing them are also discussed. Finally, we provide our perspectives on future considerations and opportunities for applying mRNA vaccines to fight against major infectious diseases and cancers. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Lipid-Based Structures.

Redox-responsive polymer inhibits macrophages uptake for effective intracellular gene delivery and enhanced cancer therapy

The development of advanced gene delivery carriers with stimuli-responsive release manner for tumor therapeutics is desirable, since they can exclusively release the therapeutic gene via their structural changes in response to the specific stimuli of the target site. Moreover, interactions between macrophages and drug delivery systems (DDSs) seriously impair the treatment efficiency of DDSs, thus macrophages uptake inhibition would to some extent improve the intracellular uptake of DDSs in tumor cells. Herein, a PEGylated redox-responsive gene delivery system was developed for effective cancer therapy. PEG modified glycolipid-like polymer (P-CSSO) was electrostatic interacted with p53 to form P-CSSO/p53 complexes, which exhibited an enhanced redox sensitivity in that the disulfide bond was degraded and the rate the plasmid released from P-CSSO was 2.29-fold that of nonresponsive platform (P-CSO-SA) in 10 mM levels of glutathione (GSH). PEGylation could significantly weaken macrophages uptake, while enhance the accumulation of P-CSSO in tumor cells both in vitro and in vivo. Compared with nonresponsive complexes (P-CSO-SA/p53) (59.2%) and Lipofectamine™ 2000/p53 complexes (52.0%), the tumor inhibition rate of P-CSSO/p53 complexes (77.1%) significantly increased, which was higher than CSSO/p53 complexes (69.9%). The present study indicates that tumor microenvironment sensitive and macrophages uptake suppressive P-CSSO/p53 is a powerful in vivo gene delivery system for enhanced anticancer therapy.

Glucose metabolism during in vitro maturation of mouse oocytes: An study using RNA interference

In previous studies on glucose metabolism during in vitro maturation, intact cumulus-oocyte complexes (COCs) were treated with enzyme inhibitors/activators. Because inhibitors/activators may have non-specificity and/or toxicity, and culture of COCs cannot differentiate whether glucose metabolism of cumulus cells (CCs) or that of the oocyte supports oocyte maturation, results from the previous studies must be verified by silencing genes in either CCs or cumulus-denuded oocytes (DOs). In this study, RNAi was adopted to specify the effects of glucose metabolism in CCs or DOs on oocyte maturation. Although silencing either glyceraldehyde 3-phosphate dehydrogenase (GAPDH) or glucose-6-phosphate dehydrogenase (G6PD) genes in CCs significantly decreased competence of the cocultured DOs, silencing G6PD impaired competence to a greater extent. While silencing G6PD or GAPDH of CCs decreased glutathione and ATP contents of cocultured DOs to similar extents, silencing G6PD increased oxidative stress as well. Analysis on metabolite contents and oxidative stress index and culture of DOs in medium conditioned with gene-silenced CCs indicated that CCs supported oocyte maturation by releasing glucose metabolites. Silencing mitochondrial pyruvate carrier 1 or NADH dehydrogenase (ubiquintone) flavoprotein 1 of DOs significantly impaired their maturation. The results have unequivocally confirmed that CCs promote oocyte maturation by releasing glucose metabolites from both pentose phosphate pathway (PPP) and glycolysis. Pyruvate is transferred into DOs by mitochondrial pyruvate carrier (MPC) and utilized through mitochondrial electron transport to support maturation.

Charge-Reversible Multifunctional HPMA Copolymers for Mitochondrial Targeting

Mitochondrial-oriented delivery of anticancer drugs has been considered as a promising strategy to improve the antitumor efficiency of chemotherapeutics. However, the physiological and biological barriers from the injection site to the final mitochondrial action site remain great challenges. Herein, a novel mitochondrial-targeted multifunctional nanocomplex based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers (MPC) is designed to enhance drug accumulation in mitochondria. MPC possesses various functions such as extracellular pH response, superior cellular uptake, lysosomal escape, and mitochondrial targeting. In detail, MPC was formed by two oppositely charged HPMA copolymers, that is, positively charged mitochondrial-targeting guanidine group-modified copolymers and charge-reversible 2,3-dimethylmaleic anhydride (DMA)-modified copolymers (P-DMA). It was validated that MPC could remain stable in the blood circulation (pH 7.4) but could be cleaved to expose the positive charge of the guanidine group immediately in response to the mild acidity of tumor tissues (pH 6.5). The gradual exposure of positively charged guanidine will simultaneously facilitate endocytosis, endosomal/lysosomal escape, and mitochondrial targeting. The in vitro experiments showed that compared with copolymers without guanidine modification, the cellular uptake and mitochondrial-targeting ability of MPC in the simulated tumor environment (MPC@pH6.5) separately increased 4.3- and 23.8-fold, respectively. The in vivo experiments were processed on B16F10 tumor-bearing C57 mice, and MPC showed the highest accumulation in the tumor site and a peak tumor inhibition rate of 82.9%. In conclusion, multifunctional mitochondrial-targeting HPMA copolymers provide a novel and versatile approach for cancer therapy.