Get out or die trying: Peptide- and protein-based endosomal escape of RNA therapeutics

Advancements and challenges in developing in vivo CAR T cell therapies for cancer treatment

The Chimeric Antigen Receptor (CAR) T cell therapy has emerged as a ground-breaking immunotherapeutic approach in cancer treatment. To overcome the complexity and high manufacturing cost associated with current ex vivo CAR T cell therapy products, alternative strategies to produce CAR T cells directly in the body have been developed in recent years. These strategies involve the direct infusion of CAR genes via engineered nanocarriers or viral vectors to generate CAR T cells in situ. This review offers a comprehensive overview of recent advancements in the development of T cell-targeted CAR generation in situ. Additionally, it identifies the challenges associated with in vivo CAR T method and potential strategies to overcome these issues.

Strategies and mechanisms for endosomal escape of therapeutic nucleic acids

Despite impressive recent establishment of therapeutic nucleic acids as drugs and vaccines, their broader medical use is impaired by modest performance in intracellular delivery. Inefficient endosomal escape presents a major limitation responsible for inadequate cytosolic cargo release. Depending on the carrier, this endosomal barrier can strongly limit or even abolish nucleic acid delivery. Different recent endosomal escape strategies and their hypothesized mechanisms are reviewed.

The intracellular visualization of exogenous DNA in fluorescence microscopy

In the development of non-viral gene delivery vectors, it is essential to reliably localize and quantify transfected DNA inside the cell. To track DNA, fluorescence microscopy methods are commonly applied. These mostly rely on fluorescently labeled DNA, DNA binding proteins fused to a fluorescent protein, or fluorescence in situ hybridization (FISH). In addition, co-stainings are often used to determine the colocalization of the DNA in specific cellular compartments, such as the endolysosomes or the nucleus. We provide an overview of these DNA tracking methods, advice on how they should be combined, and indicate which co-stainings or additional methods are required to draw precise conclusions from a DNA tracking experiment. Some emphasis is given to the localization of exogenous DNA inside the nucleus, which is the last step of DNA delivery. We argue that suitable tools which allow for the nuclear detection of faint signals are still missing, hampering the rational development of more efficient non-viral transfection systems.

Interaction proteomics analysis to provide insight into TFAMoplex-mediated transfection

In an earlier investigation, our group introduced the TFAMoplex, a transfection agent based on the mitochondrial transcription factor A (TFAM) protein, which complexes DNA into nanoparticles. The original TFAMoplex further contained a bacterial phospholipase to achieve endosomal escape, and the vaccinia-related kinase 1 (VRK1), which significantly boosted the transfection efficiency of the system by an unknown mechanism. This study aims at replacing VRK1 within the TFAMoplex with dynein light chain proteins, specifically RP3, to directly tether the complexes to the dynein motor complex for enhanced cytosolic transport. To confirm the interaction between the dynein complex and the resulting fusion protein, we examined the binding kinetics of TFAM-RP3 to the dynein intermediate chains 1 and 2. Furthermore, we established a proteomics-based assay to compare cytosolic protein interactions of different TFAMoplex variants, including the RP3-modified version and the original VRK1-containing system. In the group of the VRK1-containing TFAMoplex, significant shifts of protein interactors were observed, especially for nucleolar proteins. Leveraging this knowledge, we incorporated one of these nuclear proteins, leucine-rich repeat-containing protein 59 (LRRC59), into the TFAMoplex, resulting in a significant improvement of transfection properties compared to the RP3-modified system and comparable levels versus the original, VRK1-containing version. This study not only advances our comprehension of the TFAMoplex system but also offers broader insights into the potential of protein engineering for designing effective gene delivery systems.

Biodynamers: applications of dynamic covalent chemistry in single-chain polymer nanoparticles

Dynamic Covalent Chemistry (DCC) enables the development of responsive molecular systems through the integration of reversible bonds at the molecular level. These systems are thermodynamically stable and capable of undergoing various molecular assemblies and transformations, allowing them to adapt to changes in environmental conditions like temperature and pH. Introducing DCC into the field of polymer science has led to the design of Single-Chain Nanoparticles (SCNPs), which are formed by self-folding via intramolecular crosslinking mechanisms. Defined by their adaptability, SCNPs mimic biopolymers in size and functionality. Biodynamers, a subclass of SCNPs, are specifically designed for their stimuli-responsive and tunable, dynamic properties. Mimicking complex biological structures, their scope of application includes target-specific and pH-responsive drug delivery, enhanced cellular uptake and endosomal escape. In this manuscript, we discuss the integration of DCC for the design of SCNPs, focusing particularly on the characteristics of biodynamers and their biomedical and pharmaceutical applications. By underlining their potential, we highlight the factors driving the growing interest in SCNPs, providing an overview of recent developments and future perspectives in this research field.

Dual Effect by Chemical Electron Transfer Enhanced siRNA Lipid Nanoparticles: Reactive Oxygen Species-Triggered Tumor Cell Killing Aggravated by Nrf2 Gene Silencing

Insufficient endosomal escape presents a major hurdle for successful nucleic acid therapy. Here, for the first time, a chemical electron transfer (CET) system was integrated into small interfering RNA (siRNA) lipid nanoparticles (LNPs). The CET acceptor can be chemically excited using the generated energy between the donor and hydrogen peroxide, which triggers the generation of reactive oxygen species (ROS), promoting endosomal lipid membrane destabilization. Tetra-oleoyl tri-lysino succinoyl tetraethylene pentamine was included as an ionizable lipopeptide with a U-shaped topology for effective siRNA encapsulation and pH-induced endosomal escape. LNPs loaded with siRNA and CET components demonstrated a more efficient endosomal escape, as evidenced by a galectin-8-mRuby reporter; ROS significantly augmented galectin-8 recruitment by at least threefold compared with the control groups, with a p value of 0.03. Moreover, CET-enhanced LNPs achieved a 24% improvement in apoptosis level by knocking down the tumor-protective gene nuclear factor erythroid 2-related factor 2, boosting the CET-mediated ROS cell killing.

Recent Progress in the Endosomal Escape Mechanism and Chemical Structures of Polycations for Nucleic Acid Delivery

Nucleic acid-based therapies are seeing a spiralling surge. Stimuli-responsive polymers, especially pH-responsive ones, are gaining widespread attention because of their ability to efficiently deliver nucleic acids. These polymers can be synthesized and modified according to target requirements, such as delivery sites and the nature of nucleic acids. In this regard, the endosomal escape mechanism of polymer-nucleic acid complexes (polyplexes) remains a topic of considerable interest owing to various plausible escape mechanisms. This review describes current progress in the endosomal escape mechanism of polyplexes and state-of-the-art chemical designs for pH-responsive polymers. The importance is also discussed of the acid dissociation constant (i.e., pKa) in designing the new generation of pH-responsive polymers, along with assays to monitor and quantify the endosomal escape behavior. Further, the use of machine learning is addressed in pKa prediction and polymer design to find novel chemical structures for pH responsiveness. This review will facilitate the design of new pH-responsive polymers for advanced and efficient nucleic acid delivery.

Current RNA strategies in treating cardiovascular diseases

Cardiovascular disease (CVD) continues to impose a significant global health burden, necessitating the exploration of innovative treatment strategies. Ribonucleic acid (RNA)-based therapeutics have emerged as a promising avenue to address the complex molecular mechanisms underlying CVD pathogenesis. We present a comprehensive review of the current state of RNA therapeutics in the context of CVD, focusing on the diverse modalities that bring about transient or permanent modifications by targeting the different stages of the molecular biology central dogma. Considering the immense potential of RNA therapeutics, we have identified common gene targets that could serve as potential interventions for prevalent Mendelian CVD caused by single gene mutations, as well as acquired CVDs developed over time due to various factors. These gene targets offer opportunities to develop RNA-based treatments tailored to specific genetic and molecular pathways, presenting a novel and precise approach to address the complex pathogenesis of both types of cardiovascular conditions. Additionally, we discuss the challenges and opportunities associated with delivery strategies to achieve targeted delivery of RNA therapeutics to the cardiovascular system. This review highlights the immense potential of RNA-based interventions as a novel and precise approach to combat CVD, paving the way for future advancements in cardiovascular therapeutics.

Protein-based nanoparticles for therapeutic nucleic acid delivery

To realize the full potential of emerging nucleic acid therapies, there is a need for effective delivery agents to transport cargo to cells of interest. Protein materials exhibit several unique properties, including biodegradability, biocompatibility, ease of functionalization via recombinant and chemical modifications, among other features, which establish a promising basis for therapeutic nucleic acid delivery systems. In this review, we highlight progress made in the use of non-viral protein-based nanoparticles for nucleic acid delivery in vitro and in vivo, while elaborating on key physicochemical properties that have enabled the use of these materials for nanoparticle formulation and drug delivery. To conclude, we comment on the prospects and unresolved challenges associated with the translation of protein-based nucleic acid delivery systems for therapeutic applications.

Insight into Steroid-Induced ONFH: The Molecular Mechanism and Function of Epigenetic Modification in Mesenchymal Stem Cells

Osteonecrosis of the femoral head (ONFH) is a common refractory orthopedic disease, which is one of the common causes of hip pain and dysfunction. ONFH has a very high disability rate, which is associated with a heavy burden to patients, families, and society. The pathogenesis of ONFH is not completely clear. At present, it is believed that it mainly includes coagulation dysfunction, abnormal lipid metabolism, an imbalance of osteogenic/adipogenic differentiation, and poor vascularization repair. The prevention and treatment of ONFH has always been a great challenge for clinical orthopedic surgeons. However, recent studies have emphasized that the use of mesenchymal stem cells (MSCs) to treat steroid-induced ONFH (SONFH) is a promising therapy. This review focuses on the role and molecular mechanism of epigenetic regulation in the progress of MSCs in the treatment of SONFH, and discusses the significance of the latest research in the treatment of SONFH from the perspective of epigenetics.

Protein-based delivery systems for RNA delivery

RNA-based therapeutics have emerged as promising approaches to modulate gene expression and generate therapeutic proteins or antigens capable of inducing immune responses to treat a variety of diseases, such as infectious diseases, cancers, immunologic disorders, and genetic disorders. However, the efficient delivery of RNA molecules into cells poses significant challenges due to their large molecular weight, negative charge, and susceptibility to degradation by RNase enzymes. To overcome these obstacles, viral and non-viral vectors have been developed, including lipid nanoparticles, viral vectors, proteins, dendritic macromolecules, among others. Among these carriers, protein-based delivery systems have garnered considerable attention due to their potential to address specific issues associated with nanoparticle-based systems, such as liver accumulation and immunogenicity. This review provides an overview of currently marketed RNA drugs, underscores the significance of RNA delivery vector development, delineates the essential characteristics of an ideal RNA delivery vector, and introduces existing protein carriers for RNA delivery. By offering valuable insights, this review aims to serve as a reference for the future development of protein-based delivery vectors for RNA therapeutics.

Overcoming delivery barriers for RNA therapeutics in the treatment of rheumatoid arthritis

RNA therapeutics can manipulate gene expression or protein production, making them suitable for treating a wide range of diseases. Theoretically, any disease that has a definite biological target would probably find feasible therapeutic approach from RNA-based therapeutics. Numerous clinical trials using RNA therapeutics fighting against cancer, infectious diseases or inherited diseases have been reported and achieved desirable therapeutic efficacy. So far, encouraging findings from various animal experimental studies have also confirmed the great potential of RNA-based therapies in the treatment of rheumatic arthritis (RA). However, the in vivo multiple physiological barriers still seriously compromise the therapeutic efficacy of RNA drugs. Thus, safe and effective delivery strategies for RNA therapeutics are quite essential for their further and wide application in RA therapy. In this review, we will discuss the recent progress achieved using RNA-based therapeutics and focus on delivery strategies that can overcome the in vivo delivery barriers in RA treatment. Furthermore, discussion about the existing problems in current RNA delivery systems for RA therapy has been also included here.