Poly(glycoamidoamine) brush nanomaterials for systemic siRNA delivery in vivo

Treatment of Ulcerative Colitis by Cationic Liposome Delivered NLRP3 siRNA

Purpose

The abnormal activation of NLRP3 inflammasome is related to the occurrence and development of ulcerative colitis (UC). However, the ideal drug and delivery system remain important factors limiting the targeting of NLRP3 inflammasome in UC therapy. Gene therapy by delivering siRNA is effective in treating various diseases. Therefore, delivering siNLRP3 using an ideal vector for UC treatment is necessary.

Materials and Methods

Nanoparticles delivering siNLRP3 were developed based on cationic liposome (CLP/siNLRP3). Their ability to inhibit NLRP3 inflammasome activation was monitored using Western blot (WB) and Enzyme-linked Immunosorbent Assay (ELISA). The ASC oligomerization in LPS-primed peritoneal macrophages (PMs) was detected by WB and immunofluorescence. Moreover, we assessed the role of CLP/siNLRP3 on dextran sodium sulfate (DSS)-induced UC by examining NLRP3 levels, pro-inflammatory cytokines expression, and disease-associated index (DAI). Flow cytometry (FCM) was used to detect the contents of macrophages and T cells. Finally, we assessed the safety of CLP/siNLRP3.

Results

The prepared CLP was spherical, with a small particle size (94 nm) and low permeability. The CLP could efficiently protect siNLRP3 from degradation and then deliver siNLRP3 into PMs, inhibiting NLRP3 inflammasome activation. Also, the CLP/siNLRP3 could inhibit the secretion of mature IL-1β and IL-18 from PMs, thereby achieving a favorable anti-inflammation effect. In vivo, CLP/siNLRP3 could effectively alleviate intestinal injury in UC mice, which was attributed to down-regulating levels of IL-1β and IL-18, inhibiting infiltration of macrophages and other immune cells, and the polarization of M1 macrophages. Finally, pathological testing of tissue sections and blood biochemical tests showed no significant toxic effects of CLP/siNLRP3.

Conclusion

We introduced a prospective approach for the efficient delivery of siRNA in vitro and in vivo with high safety and stability, which was found to have great potential in treating NLRP3-driven diseases in an RNA-silencing manner.

Lipids and Lipid Derivatives for RNA Delivery

RNA-based therapeutics have shown great promise in treating a broad spectrum of diseases through various mechanisms including knockdown of pathological genes, expression of therapeutic proteins, and programmed gene editing. Due to the inherent instability and negative-charges of RNA molecules, RNA-based therapeutics can make the most use of delivery systems to overcome biological barriers and to release the RNA payload into the cytosol. Among different types of delivery systems, lipid-based RNA delivery systems, particularly lipid nanoparticles (LNPs), have been extensively studied due to their unique properties, such as simple chemical synthesis of lipid components, scalable manufacturing processes of LNPs, and wide packaging capability. LNPs represent the most widely used delivery systems for RNA-based therapeutics, as evidenced by the clinical approvals of three LNP-RNA formulations, patisiran, BNT162b2, and mRNA-1273. This review covers recent advances of lipids, lipid derivatives, and lipid-derived macromolecules used in RNA delivery over the past several decades. We focus mainly on their chemical structures, synthetic routes, characterization, formulation methods, and structure-activity relationships. We also briefly describe the current status of representative preclinical studies and clinical trials and highlight future opportunities and challenges.

Recent progress in nanomaterials for nucleic acid delivery in cancer immunotherapy

The combination of gene therapy and immunotherapy has the potential to systemically promote anti-tumor effects while reducing adverse reactions. Small interfering RNA (siRNA) has generated great interest in biology, engineering and medicine, especially for cancer treatment due to its ability to knock down genes of interest. Nanomaterials play significant roles in the design of delivery systems of siRNA, and nanomaterial-mediated siRNA delivery in cancer immunotherapy is one of the most important directions for future clinical cancer treatment. Here, we review the recent advances in nanomaterial mediated targeted delivery of siRNA to dendritic cells (DCs), tumor-associated macrophages (TAMs), immune checkpoint inhibitors, B lymphocytes, natural killer cells (NKs), and immunosuppressive cytokines. Fundamental challenges in nucleic acid delivery enabled by bio-barriers, its promising solution strategies and future directions are also reviewed.

Recent advances in polymeric materials for the delivery of RNA therapeutics

Introduction: The delivery of nucleic acid therapeutics through non-viral carriers face multiple biological barriers that reduce their therapeutic efficiency. Despite great progress, there remains a significant technological gap that continues to limit clinical translation of these nanocarriers. A number of polymeric materials are being exploited to efficiently deliver nucleic acids and achieve therapeutic effects. Areas covered: We discuss the recent advances in the polymeric materials for the delivery of nucleic acid therapeutics. We examine the use of common polymer architectures and highlight the challenges that exist for their development from bench side to clinic. We also provide an overview of the most notable improvements made to circumvent such challenges, including structural modification and stimuli-responsive approaches, for safe and effective nucleic acid delivery. Expert opinion: It has become apparent that a universal carrier that follows 'one-size' fits all model cannot be expected for delivery of all nucleic acid therapeutics. Carriers need to be designed to exhibit sensitivity and specificity toward individual targets diseases/indications, and relevant subcellular compartments, each of which possess their own unique challenges. The ability to devise synthetic methods that control the molecular architecture enables the future development that allow for the construction of 'intelligent' designs.

ROS-Responsive Polymeric siRNA Nanomedicine Stabilized by Triple Interactions for the Robust Glioblastoma Combinational RNAi Therapy

Small interfering RNA (siRNA) holds inherent advantages and great potential for treating refractory diseases. However, lack of suitable siRNA delivery systems that demonstrate excellent circulation stability and effective at-site delivery ability is currently impeding siRNA therapeutic performance. Here, a polymeric siRNA nanomedicine (3I-NM@siRNA) stabilized by triple interactions (electrostatic, hydrogen bond, and hydrophobic) is constructed. Incorporating extra hydrogen and hydrophobic interactions significantly improves the physiological stability compared to an siRNA nanomedicine analog that solely relies on the electrostatic interaction for stability. The developed 3I-NM@siRNA nanomedicine demonstrates effective at-site siRNA release resulting from tumoral reactive oxygen species (ROS)-triggered sequential destabilization. Furthermore, the utility of 3I-NM@siRNA for treating glioblastoma (GBM) by functionalizing 3I-NM@siRNA nanomedicine with angiopep-2 peptide is enhanced. The targeted Ang-3I-NM@siRNA exhibits superb blood-brain barrier penetration and potent tumor accumulation. Moreover, by cotargeting polo-like kinase 1 and vascular endothelial growth factor receptor-2, Ang-3I-NM@siRNA shows effective suppression of tumor growth and significantly improved survival time of nude mice bearing orthotopic GBM brain tumors. New siRNA nanomedicines featuring triple-interaction stabilization together with inbuilt self-destruct delivery ability provide a robust and potent platform for targeted GBM siRNA therapy, which may have utility for RNA interference therapy of other tumors or brain diseases.

Lipidoid-siRNA Nanoparticle-Mediated IL-1β Gene Silencing for Systemic Arthritis Therapy in a Mouse Model

Interleukin-1 beta (IL-1β) plays a central role in the induction of rheumatoid arthritis (RA). In the present study, we demonstrated that lipidoid-polymer hybrid nanoparticle (FS14-NP) can efficiently deliver siRNA against IL-1β (siIL-1β) to macrophages and effectively suppress the pathogenesis of experimental arthritis induced by collagen antibody (CAIA mice). FS14-NP/siIL-1β achieved approximately 70% and 90% gene-silencing efficiency in the RAW 264.7 cell line and intraperitoneal macrophages, respectively. Intravenous administration of FS14-NP/siRNA led to rapid accumulation of siRNA in macrophages within the arthritic joints. Furthermore, FS14-NP/siIL-1β treatment lowered the expression of pro-inflammatory cytokines in arthritic joints and dramatically attenuated ankle swelling, bone erosion, and cartilage destruction. These results demonstrate that FS14-NP/siIL-1β may represent an effective therapy for systemic arthritis and other inflammatory disorders.

Recent development of synthetic nonviral systems for sustained gene delivery

Sustained gene delivery is of particular importance today because it circumvents the need for repeated therapeutic administration and provides spatial and temporal control of the release profile. Better understanding of the genetic basis of diseases and advances in gene therapy have propelled significant research on biocompatible gene carriers for therapeutic purposes. Varied biodegradable polymer-based architectures have been used to create new compositions with unique properties suitable for sustained gene delivery. This review presents the most recent advances in various polymeric systems: hydrogels, microspheres, nanospheres and scaffolds, having complex architectures to encapsulate and deliver functional genes. Through the recombination of different existing polymer systems, the multicomplex systems can be further endowed with new properties for better-targeted biomedical applications.