The design of cationic liposomes for efficient mRNA delivery can significantly improve mRNA-based therapies. Lipoplexes based on polycationic lipid 1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosane tetrahydrochloride (2X3) and helper lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) were formulated in different molar ratios (1:1, 1:2, 1:3) to efficiently deliver model mRNAs to BHK-21 and A549. The objective of this study was to examine the effect of 2X3-DOPE composition as well as lipid-to-mRNA ratio (amino-to-phosphate group ratio, N/P) on mRNA transfection. We found that lipoplex-mediated transfection efficiency depends on both liposome composition and the N/P ratio. Lipoplexes with an N/P ratio of 10/1 showed nanometric hydrodynamic size, positive ζ potential, maximum loading, and transfection efficiency. Liposomes 2X3-DOPE (1:3) provided the superior delivery of both mRNA coding firefly luciferase and mRNA-eGFP into BHK-21 cells and A549 cells, compared with commercial Lipofectamine MessengerMax.

Background: Exosomes are involved in intercellular communication and can transfer regulatory molecules between cells. Consequently, they can participate in host immune response regulation. For the influenza A virus (IAV), there is very limited information on changes in exosome composition during cell infection shedding light on the potential role of these extracellular membrane vesicles. Thus, the aim of our work was to study changes in exosomal composition following IAV infection of cells, as well as to evaluate their effect on uninfected cells. Methods: To characterize changes in the composition of cellular miRNAs and mRNAs of exosomes during IAV infection of A549 cells, NGS was used, as well as PCR to identify viral genes. Naïve A549 cells were stimulated with infected-cell-secreted exosomes for studying their activity. Changes in the expression of genes associated with the cell’s immune response were shown using PCR. The effect of exosomes on IAV replication was shown in MDCK cells using In-Cell ELISA and PCR of the supernatants. Results: A change in the miRNA composition (miR-21-3p, miR-26a-5p, miR-23a-5p, miR-548c-5p) and mRNA composition (RPL13A, MKNK2, TRIB3) of exosomes under the influence of the IAV was shown. Many RNAs were involved in the regulation of the immune response of the cell, mainly by suppressing it. After exosome stimulation of naïve cells, a significant decrease in the expression of genes involved in the immune response was shown (RIG1, IFIT1, MDA5, COX2, NFκB, AnxA1, PKR, IL6, IL18). When infecting MDCK cells, a significant decrease in nucleoprotein levels was observed in the presence of exosomes secreted by mock-infected cells. Viral levels in supernatants also decreased. Conclusions: Exosomes secreted by IAV-infected cells could reduce the immune response of neighboring intact cells, leading to more effective IAV replication. This may be associated both with regulatory functions of cellular miRNAs and mRNAs carried by exosomes, or with the presence of viral mRNAs encoding proteins with an immunosuppressive function.

Background/Objectives: The development of polymer–lipid hybrid nanoparticles (PLNs) is a promising area of research, as it can help increase the stability of cationic lipid carriers. Hybrid PLNs are core–shell nanoparticle structures that combine the advantages of both polymer nanoparticles and liposomes, especially in terms of their physical stability and biocompatibility. Natural polymers such as polyhydroxyalkanoate (PHA) can be used as a matrix for the PLNs’ preparation. Methods: In this study, we first obtained stable cationic hybrid PLNs using a cationic liposome (CL) composed of a polycationic lipid 2X3 (1,26-bis(cholest-5-en-3β-yloxycarbonylamino)-7,11,16,20-tetraazahexacosane tetrahydrochloride), helper lipid DOPE (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine), and the hydrophobic polymer mcl-PHA, which was produced by the soil bacterium Pseudomonas helmantisensis P1. Results: The new polymer-lipid carriers effectively encapsulated and delivered model mRNA-eGFP (enhanced green fluorescent protein mRNA) to BHK-21 cells. We then evaluated the role of mcl-PHA in increasing the stability of cationic PLNs in ionic solutions using dynamic light scattering data, electrophoretic mobility, and transmission electron microscopy techniques. Conclusions: The results showed that increasing the concentration of PBS (phosphate buffered saline) led to a decrease in the stability of the CLs. At high concentrations of PBS, the CLs aggregate. In contrast, the presence of isotonic PBS did not result in the aggregation of PLNs, and the particles remained stable for 120 h when stored at +4 °C. The obtained results show that PLNs hold promise for further in vivo studies on nucleic acid delivery.

BACKGROUND: The delivery of nucleic acids to mesenchymal stem cells, which are used as model objects in in vitro experiments or as therapeutic agents in regenerative medicine and oncology, is an actively developing area of research. Existing non-viral delivery systems either have low effectiveness or highly toxic to mesenchymal stem cells. Therefore, the development of new carriers has become an urgent priority. AIM: To demonstrate the feasibility of delivering model messenger RNA and small interfering RNA to rat heart mesenchymal stem cells (MSCs) in vitro using original cationic liposomes 2X3-DOPE (1:3 molar ratio) and to evaluate the influence of exosomes incorporated into hybrid nanoparticles with 2X3-DOPE on the efficiency of RNA delivery. METHODS: Exosomes were isolated using a standard ultracentrifugation technique followed by characterization of the obtained vesicles through Western blotting, transmission electron microscopy, atomic force microscopy, and hydrodynamic diameter measurement using dynamic light scattering. Small interfering RNA was chemically synthesized; whereas messenger RNA was obtained by in vitro transcription. Complexes of liposomes or hybrid nanoparticles with RNA were prepared by mixing; the properties of the resulting particles were assessed using dynamic light scattering and atomic force microscopy. To evaluate the efficiency of RNA delivery to rat heart mesenchymal stem cells derived from both healthy and ischemic myocardium, we used fluorescence microscopy, laser scanning confocal microscopy, and flow cytometry. RESULTS: Complexes of cationic liposomes 2X3-DOPE (1:3 molar ratio) with messenger RNA and 2X3-DOPE modified with DSPE-PEG2000 (0.62 mol%) complexed with small interfering RNA were successfully prepared and characterized. It was demonstrated that 2X3-DOPE is ineffective for messenger RNA delivery to rat cardiac mesenchymal stem cells; whereas hybrid nanoparticles incorporating exosomes based on these liposomes exhibited up to 40% transfection efficiency. In addition, 2X3-DOPE modified with DSPE-PEG2000 (0.62 mol%) was effective for small interfering RNA delivery to rat cardiac mesenchymal stem cells, achieving up to 90% transfection efficiency; whereas the use of hybrid nanoparticles based on this formulation resulted in 100% transfected cells with more than a twofold increase in small interfering RNA in the cells as indicated by the average fluorescence intensity. CONCLUSION: Cationic liposomes 2X3-DOPE (1:3 molar ratio) modified with DSPE-PEG2000 (0.62 mol%) are promising vehicles for small interfering RNA delivery to mesenchymal stem cells, both independently and in combination with exosomes. Exosomes integrated in hybrid nanoparticles based on 2X3-DOPE improve the transfection efficiency of both messenger RNA and small interfering RNA in rat cardiac mesenchymal stem cells in vitro.

Nanoparticles based on biodegradable polymers find numerous applications in medicine as substances for intracellular drug delivery. Biosynthetically produced poly-3-hydroxyalkanoates (P3HAs) are among the most promising polymers of a lipid nature. In particular, polyhydroxybutyrate and polyhydroxyvalerate (scl-poly-3-hydroxyalkanoates) are widely used compounds, which are soluble only in organochlorine solvents. The use of organochlorine solvents faces several obstacles, since such chemicals may exhibit carcinogenic effects on the human body. However, the P3Has compounds consisting of hydroxybutyric acid residues with 6–14 carbon atoms in the main chain (mcl-poly-3-hydroxyalkanoates) are soluble not only in CHCl₃ or CH₂Cl₂ but also in paraffins. These hydrocarbons, such as n-hexane, can be easily separated from aqueous solutions and are not known to exhibit high cytotoxicity. Consequently, the application of mcl-poly-3-hydroxyalkanoates can prevent the contamination of prepared dosage forms with organochlorine compounds. To this end, a methodology for the synthesis of mcl-P3HA nanoparticles stabilized with the Tween 80 nonionic surfactant was proposed. The ratio between the concentration of P3HA and the detergent was optimized. The present study revealed that the obtained particles have an average size of 200±90 nm and a zeta potential of -17±5 mV. Upon investigating the stability of the particle solution at 4 °C, it was found that the nanoparticles did not alter their size and zeta potential for 90 days. The fluorescence microscopy method showed that they could be delivered into BHK-21 cells within 2 h. In addition, the nanoparticles synthesized had no toxic effect on BHK-21 cells at a concentration of up to 200 μg/mL.