Structure optimization of dendritic lipopeptide based gene vectors with the assistance from molecular dynamic simulation

Development and applications of lipid hydrophilic headgroups for nucleic acid therapy

Nucleic acid therapy is currently the most promising method for treating tumors and genetic diseases and for preventing infectious diseases. However, the biggest obstacle to this therapy is delivery of the nucleic acids to the target site, which requires overcoming problems such as capture by the immune system, the need to penetrate biofilms, and degradation of nucleic acid performance. Designing suitable delivery vectors is key to solving these problems. Lipids-which consist of a hydrophilic headgroup, a linker, and a hydrophobic tail-are crucial components for the construction of vectors. The headgroup is particularly important because it affects the drug encapsulation rate, the vector cytotoxicity, and the transfection efficiency. Herein, we focus on various headgroup structures (tertiary amines, quaternary ammonium salts, peptides, piperazines, dendrimers, and several others), and we summarize and classify important lipid-based carriers that have been developed in recent years. We also discuss applications of cationic lipids with various headgroups for delivery of nucleic acid drugs, and we analyze how headgroup structure affects transport efficiency and carrier toxicity. Finally, we briefly describe the challenges of developing novel lipid carriers, as well as their prospects.

Hierarchically decorated magnetic nanoparticles amplify the oxidative stress and promote the chemodynamic/magnetic hyperthermia/immune therapy

Magnetic nanoparticles (MNPs) are promising in tumor treatments due to their capacity for magnetic hyperthermia therapy (MHT), chemodynamic therapy (CDT), and immuno-related therapies, but still suffer from unsatisfactory tumor inhibition in the clinic. Insufficient hydrogen peroxide supply, glutathione-induced resistance, and high-density extracellular matrix (ECM) are the barriers. Herein, we hierarchically decorated MNPs with disulfide bonds (S-S), dendritic L-arginine (R), and glucose oxidase (GOx) to form a nanosystem (MNPs-SS-R-GOx). Its outer GOx layer not only enhanced the H2O2 supply to produce .OH by Fenton reaction, but also generated stronger oxidants (ONOO-) together with the interfaced R layer. The inner S-S layer consumed glutathione to interdict its reaction with oxidants, thus enhancing CDT effects. Importantly, the generated ONOO- tripled the MMP-9 expression to induce ECM degradation, enabling much deeper penetration of MNPs and benefiting CDT, MHT, and immunotherapy. Finally, the MNPs-SS-R-GOx demonstrated a remarkable 91.7% tumor inhibition in vivo. STATEMENT OF SIGNIFICANCE: Magnetic nanoparticles (MNPs) are a promising tumor therapeutic agent but with limited effectiveness. Our hierarchical MNP design features disulfide bonds (S-S), dendritic L-arginine (R), and glucose oxidase (GOx), which boosts H2O2 supply for ·OH generation in Fenton reactions, produces potent ONOO-, and enhances chemodynamic therapy via glutathione consumption. Moreover, the ONOO- facilitates the upregulation of matrix metalloprotein expression beneficial for extracellular matrix degradation, which in turn enhances the penetration of MNPs and benefits the antitumor CDT/MHT/immuno-related therapy. In vivo experiments have demonstrated an impressive 91.7% inhibition of tumor growth. This hierarchical design offers groundbreaking insights for further advancements in MNP-based tumor therapy. Its implications extend to a broader audience, encompassing those interested in material science, biology, oncology, and beyond.

A DNA vaccine (EG95-PT1/2/3-IL2) encoding multi-epitope antigen and IL-2 provokes efficient and long-term immunity to echinococcosis

Echinococcosis is a highly prevalent global zoonosis, and vaccines are required. The commercial vaccine based on a protein-based subunit (EG95), however, is limited by its insufficient cellular immunity, a short protection period, and limited prevention against novel mutant strains. Herein, we applied bioinformatics to develop a DNA vaccine (pEG95-IL2) expressing both multi-epitope-based antigens (EG95-PT1/2/3) and an IL-2 adjuvant to regulate T cell differentiation and memory cell response. EG95-PT1/2/3 was screened with hierarchical structure prediction from the epitope conformation of B cells with high confidence across various species to guarantee immunogenicity. Importantly, cationic arginine-rich lipid nanoparticles (RNP) were utilized as a delivery vehicle to form lipoplexes that had a transfection efficiency of nearly two orders of magnitude greater than that of commercial reagents (Lipofectamine 2000 and polyethyleneimine) with both immune and nonimmune cells (DC2.4 and L929 cells, respectively). RNP/pEG95-IL2 lipoplexes displayed a robust and long-term antigen expression, as well as adjuvant effects during the immunization. Consequently, intramuscular injection of RNP/pEG95-IL2 elicited similar humoral immune responses and significantly greater cellular responses in mice when compared with those of the commercial vaccine. In addition, the inoculation protocol of RNP/pEG95-IL2 with sequential booster further strengthens cellular immunity in comparison with the homologous booster. Those findings provide a promising strategy for improving plasmid vaccine efficacy.

A cationic lipid with advanced membrane fusion performance for pDNA and mRNA delivery

The success of mRNA vaccines for COVID-19 prevention raised global awareness of the importance of nucleic acid drugs. The approved systems for nucleic acid delivery were mainly formulations of different lipids, yielding lipid nanoparticles (LNPs) with complex internal structures. Due to the multiple components, the relationship between the structure of each component and the overall biological activity of LNPs is hard to study. However, ionizable lipids have been extensively explored. In contrast to former studies on the optimization of hydrophilic parts in single-component self-assemblies, we report in this study on structural alterations of the hydrophobic segment. We synthesize a library of amphiphilic cationic lipids by varying the lengths (C = 8-18), numbers (N = 2, 4), and unsaturation degrees (Ω = 0, 1) of hydrophobic tails. Notably, all self-assemblies with nucleic acid have significant differences in particle size, stability in serum, membrane fusion, and fluidity. Moreover, the novel mRNA/pDNA formulations are characterized by overall low cytotoxicity, efficient compaction, protection, and release of nucleic acids. We find that the length of hydrophobic tails dominates the formation and stability of the assembly. And at a certain length, the unsaturated hydrophobic tails enhance the membrane fusion and fluidity of assemblies and thus significantly affect the transgene expression, followed by the number of hydrophobic tails.

Multifunctional amphiphilic peptide dendrimer as nonviral gene vectors for effective cancer therapy via combined gene/photodynamic therapies

Gene therapy holds great promise for treatment of gene-associated diseases. However, safe and successful clinical application urgently requires further advancement of constructing efficient delivery systems. Herein, three amphiphilic peptide dendrimers (TTC-L-KRR/KKK/KHH), containing the natural amino acid residues (lysine K, arginine R, and histidine H) and AIE-based photosensitizer (tetraphenylethenethiophene modified cyanoacrylate, TTC) modified with alkyl chain (L), have been designed and prepared for improving therapeutic potency via the combination of gene therapy (GT) and photodynamic therapy (PDT). All three compounds possessed typical aggregation-induced emission (AIE) characteristics and ultralow critical micelle concentrations (CMCs). The liposomes consisting of amphiphilic peptide dendrimers and dioleoylphosphatidylethanolamine (DOPE) can effectively bind DNA into nanoparticles with appropriate sizes, regular morphology and good biocompatibility. Among them, liposomes TTC-L-KKK/DOPE exhibited the highest transfection efficiency up to 5.7-fold as compared with Lipo2000 in HeLa cells. Meanwhile, rapid endocytosis, successful endo/lysosomal escape, gene release and rapid nuclear delivery of DNA revealed the superiority of liposomes TTC-L-KKK/DOPE during gene delivery process. More importantly, efficient reactive oxygen species (ROS) generation by TTC-L-KKK/DOPE led to effective PDT, thus improving therapeutic potency via combining with p53 mediated-gene therapy. Our work brought novel insight and direction for the construction of bio-safe and bio-imaging liposome as the multifunctional nonviral gene vectors for the effective combined gene/photodynamic therapies.

Self-assembly of Peptide dendrimers and their bio-applications in theranostics

Nanotechnology has brought revolutionized advances in disease diagnosis and therapy. Self-assembled peptide dendrimers own novel physicochemical properties through the synergistic effects of the polypeptide chain, dendrimer and nano-structure, exhibiting great potential in theranostic. This review provides comprehensive insights into various peptide dendrimers for self-assembly. Their nanosize, morphology and composition are presented to understand self-assembly behaviors precisely. We further introduce the emerging theranostic applications based on specific imaging and efficient delivery recently.

Exploiting Peptide Self-Assembly for the Development of Minimalistic Viral Mimetics

Viruses are natural supramolecular nanostructures that form spontaneously by molecular self-assembly of complex biomolecules. Peptide self-assembly is a versatile tool that allows mimicking viruses by creating their simplified versions through the design of functional, supramolecular materials with modularity, tunability, and responsiveness to chemical and physical stimuli. The main challenge in the design and fabrication of peptide materials is related to the precise control between the peptide sequence and its resulting supramolecular morphology. We provide an overview of existing sequence patterns employed for the development of spherical and fibrillar peptide assemblies that can act as viral mimetics, offering the opportunity to tackle the challenges of viral infections.

A parallel and cascade control system: magnetofection of miR125b for synergistic tumor-association macrophage polarization regulation and tumor cell suppression in breast cancer treatment

Polarization regulation of tumor-association macrophages (TAMs) is a promising treatment method for tumors, but aiming at TAMs alone shows unsatisfactory therapeutic efficiency. Therefore, we designed a parallel and cascade control system for both macrophage polarization and tumor cell inhibition. The system is composed of cationic lipopeptides with an arginine-rich periphery (RLS) and anionic magnetic nanoparticles (MNPs) for fleet transfection of miR-125b. Based on the highly efficient magnetofection, miR-125b successfully shows a parallel effect on both M1, promoting polarization by targeting interferon regulatory factor 4 (IRF4) in macrophages, and tumor cell inhibition, by targeting ETS proto-oncogene 1 and cyclin- J. The cascading effect on M1-associated genes is upregulated by up to two orders of magnitude, while M2-associated genes are downregulated. Meanwhile, MNPs also have an effect on the TAM polarization and 4T1 tumor cell inhibition via inflammatory related gene expression and Fenton reaction. Further mimicking the co-culture of RAW264.7 and 4T1 cells in vitro confirmed the synergistic therapy effect. In the treatment of orthotopic breast cancer in mice, considerable M1 macrophage polarization was observed in the RM125b treated group, showing distinct tumor-suppressive effects, with a tumor weight reduction of 60% and tumor metastasis suppression of 50%.

Integration of Indocyanine Green Analogs as Near-Infrared Fluorescent Carrier for Precise Imaging-Guided Gene Delivery

Codelivery of diagnostic probes and therapeutic molecules often suffers from intrinsic complexity and premature leakage from or degradation of the nanocarrier. Inspired by the "Y" shape of indocyanine green (ICG), the dye is integrated in an amphiphilic lipopeptide (RNF). The hydrophilic segment is composed of arginine-rich dendritic peptides, while cyanine dyes are modified with two long carbon chains and employed as the hydrophobic moiety. They are linked through a disulfide linkage to improve the responsivity in the tumor microenvironment. After formulation with other lipopeptides at an optimized ratio, the theranostic system (RNS-2) forms lipid-based nanoparticles with slight positive zeta potential enabling efficient condensation of DNA. The RNS-2 displays glutathione responded gene release, activatable fluorescence recovery, and up to sevenfold higher in vitro transfection than Lipofectamine 2000. Compared with a Cy3 and Cy5 labeled fluorescence resonance energy transfer indicator for gene release, the "turn-on" indocyanine green analogs exhibit longer emission wavelength and better positive correlation with the dynamic processes of gene delivery. More importantly, the RNS-2 system enables efficient near infrared imaging guided gene transfer in tumor-bearing mice and thus provides more precise and accurate information on location of the cargo gene and synthesized carriers.

A nitroreductase and glutathione responsive nanoplatform for integration of gene delivery and near-infrared fluorescence imaging

A novel platform rationally integrating indocyanine green analogues and an arginine-rich dendritic peptide with both nitroreductase (NTR) and glutathione (GSH) reduction responsive linkers was developed.