Immune effect of electric charge modified influenza vaccine liposomes / 中国生物制品学杂志

@#Objective To explore the physical and chemical properties of electric charge modified liposomes and the immune enhancement effect as influenza vaccine adjuvants.Methods Four kinds of electric charge-modified liposomes were prepared with soybean lecithin,cholesterol,N-1-(2,3-dioleyloxy) propyl-N,N,N-trimethyllam-moniumchloride(DOTAP)and 1,2-dioleoyl-sn-glycero-3-phosphocholine(DOPC)(DOTAP and DOPC mass ratio 1:4,2:3,3:2 and 4:1).The tetravalent influenza vaccine was mixed with the four liposomes according to the volume fraction of 1.4:1.0,which was prepared into cationic modified influenza vaccine liposome freeze-dried powder by freeze-thaw freeze-drying method.The liposome freeze-dried powder was redissolved with PBS,the particle size and Zeta potential were measured by laserparticle size analyzer,and the encapsulation efficiency of liposome was measured by Lowry method.231 female KM mice were randomly divided into negative control group(PBS),positive control group(tetravalent vaccine bulk),cationic liposome group(four electric charge modified influenza vaccine liposomes) and neutral liposome group(non-electric charge modified influenza vaccine liposomes),which were injected intraperitoneally at 7,14 and 28 d,0.2 mL per mouse.The cellular immune effect was evaluated by MTT assay and T lymphatic surface labeling,and the humoral immune effect was evaluated by hemagglutinin inhibition(HI) at 3,7,14,28,42 and 56 d of immunization.Results When the mass ratio of DOTAP to DOPC was 4:1,the particle size and Zeta potential of cationic modified liposomes reached the maximum,which were 529.65 nm and 12.05 mV respectively,and the encapsulation efficiency was also high,which was 81.82%.Stimulus index(SI) and CD4~+/CD8~+value of spleen cells of mice in the four cationic liposome groups were significantly higher than those in the negative control group(F=4.651～25.866,each P<0.05),among which,the two indexes in 4:1 cationic liposome group were higher than those in the other three groups;mice in this group produced early humoral immune effect 3 d after immunization,and the antibody titer reached the highest 42 d after immunization and maintained a high level during the whole immunization cycle.Conclusion Cationic liposomes with different electric charge modifications improved the immune effect of influenza vaccine,the immune enhancement effect was the best and the immune effect lasted the longest when the mass ratio of DOTAP to DOPC was 4:1.

Sodium alginate coating simultaneously increases the biosafety and immunotherapeutic activity of the cationic mRNA nanovaccine

The extraordinary advantages associated with mRNA vaccines, including their high efficiency, relatively low severity of side effects, and ease of manufacture, have enabled them to be a promising immunotherapy approach against various infectious diseases and cancers. Nevertheless, most mRNA delivery carriers have many disadvantages, such as high toxicity, poor biocompatibility, and low efficiency in vivo, which have hindered the widespread use of mRNA vaccines. To further characterize and solve these problems and develop a new type of safe and efficient mRNA delivery carrier, a negatively charged SA@DOTAP-mRNA nanovaccine was prepared in this study by coating DOTAP-mRNA with the natural anionic polymer sodium alginate (SA). Intriguingly, the transfection efficiency of SA@DOTAP-mRNA was significantly higher than that of DOTAP-mRNA, which was not due to the increase in cellular uptake but was associated with changes in the endocytosis pathway and the strong lysosome escape ability of SA@DOTAP-mRNA. In addition, we found that SA significantly increased the expression of LUC-mRNA in mice and achieved certain spleen targeting. Finally, we confirmed that SA@DOTAP-mRNA had a stronger antigen-presenting ability in E. G7-OVA tumor-bearing mice, dramatically inducing the proliferation of OVA-specific CLTs and ameliorating the antitumor effect. Therefore, we firmly believe that the coating strategy applied to cationic liposome/mRNA complexes is of potential research value in the field of mRNA delivery and has promising clinical application prospects.

Inhibiting collagen I production and tumor cell colonization in the lung via miR-29a-3p loading of exosome-/liposome-based nanovesicles

The lung is one of the most common sites for cancer metastasis. Collagens in the lung provide a permissive microenvironment that supports the colonization and outgrowth of disseminated tumor cells. Therefore, down-regulating the production of collagens may contribute to the inhibition of lung metastasis. It has been suggested that miR-29 exhibits effective anti-fibrotic activity by negatively regulating the expression of collagens. Indeed, our clinical lung tumor data shows that miR-29a-3p expression negatively correlates with collagen I expression in lung tumors and positively correlates with patients' outcomes. However, suitable carriers need to be selected to deliver this therapeutic miRNA to the lungs. In this study, we found that the chemotherapy drug cisplatin facilitated miR-29a-3p accumulation in the exosomes of lung tumor cells, and this type of exosomes exhibited a specific lung-targeting effect and promising collagen down-regulation. To scale up the preparation and simplify the delivery system, we designed a lung-targeting liposomal nanovesicle (by adjusting the molar ratio of DOTAP/cholesterol-miRNAs to 4:1) to carry miR-29a-3p and mimic the exosomes. This liposomal nanovesicle delivery system significantly down-regulated collagen I secretion by lung fibroblasts in vivo, thus alleviating the establishment of a pro-metastatic environment for circulating lung tumor cells.

Enhancement of Transduction Efficiency and Antitumor Effects of IL-12N220L-expressing Adenovirus by Co-delivery of DOTAP

BACKGROUND: Adenovirus (Ad) vectors have been widely used for many gene therapy applications because of their high transduction ability and broad tropism. However, their utility for cancer gene therapy is limited by their poor transduction into cancer cells lacking the primary receptor, coxsackievirus and adenovirus receptor (CAR). METHODS: To achieve CAR-independent gene transfer via Ad, we pretreated Ad with 1,2-dioleoyl-3- trimethylammonium propane (DOTAP) and analyzed their transduction efficiency into cancer cells in vitro and in vivo comparing with the virus alone. RESULTS: Treatment of DOTAP significantly increased adenoviral gene transfer in tumor cells in vitro. Moreover, DOTAP at an optimum dose (10 microngram/ml) enhanced IL-12 transgene expression by fivefold in tumor, and twofold in serum after intratumoral injection of adenovirus expressing IL-12N220L (Ad/IL-12N220L). In addition, cotreatment of DOTAP decreased tumor growth rate in the Ad/IL-12N220L-transduced tumor model, finally leading to enhanced survival rate. CONCLUSION: Our results strongly suggest that DOTAP could be of great utility for improving adenovirus-mediated cancer gene therapy.