Multimeric RNAs for efficient RNA-based therapeutics and vaccines

Lipid nanoparticle (LNP) mediated mRNA delivery in neurodegenerative diseases

Neurodegenerative diseases (NDD) are characterized by the progressive loss of neurons and the impairment of cellular functions. Messenger RNA (mRNA) has emerged as a promising therapy for treating NDD, as it can encode missing or dysfunctional proteins and anti-inflammatory cytokines or neuroprotective proteins to halt the progression of these diseases. However, effective mRNA delivery to the central nervous system (CNS) remains a significant challenge due to the limited penetration of the blood-brain barrier (BBB). Lipid nanoparticles (LNPs) offer an efficient solution by encapsulating and protecting mRNA, facilitating transfection and intracellular delivery. This review discusses the pathophysiological mechanisms of neurological disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), Huntington's disease (HD), ischemic stroke, spinal cord injury, and Friedreich's ataxia. Additionally, it explores the potential of LNP-mediated mRNA delivery as a therapeutic strategy for these diseases. Various approaches to overcoming BBB-related challenges and enhancing the delivery and efficacy of mRNA-LNPs are discussed, including non-invasive methods with strong potential for clinical translation. With advancements in artificial intelligence (AI)-guided mRNA and LNP design, targeted delivery, gene editing, and CAR-T cell therapy, mRNA-LNPs could significantly transform the treatment landscape for NDD, paving the way for future clinical applications.

PEGylated Multimeric RNA Nanoparticles for siRNA Delivery in Traumatic Brain Injury

Traumatic brain injury (TBI) impacts millions of people globally, however currently there are no approved therapeutics that address long-term brain health. In order to create a technology that is relevant for siRNA delivery in TBI after systemic administration, sub-100 nm nanoparticles with rolling circle transcription (RCT) are synthesized and isolated in order improve payload delivery into the injured brain. Unlike conventional RCT-based RNA particles, in this method, sub-100 nm RNA nanoparticles (RNPs) are isolated. To enhance RNP pharmacokinetics, RNPs are synthesized with modified bases in order to graft polyethylene glycol (PEG) to the RNPs. PEGylated RNPs (PEG-RNPs) do not significantly impact their knockdown activity in vitro and lead to longer blood half-life after systemic administration and greater accumulation into the injured brain in a mouse model of TBI. In order to demonstrate RNA interference (RNAi) activity of RNPs, knockdown of the inflammatory cytokine TNF-α in injured brain tissue after systemic administration of RNPs in a mouse model of TBI is demonstrated. In summary, small sub-100 nm multimeric RNA nanoparticles are synthesized and isolated that can be modified using accessible chemistry in order to create a technology suitable for systemic RNAi therapy for TBI.

Microsponges: Development, Characterization, and Key Physicochemical Properties

Microsponges are promising drug delivery carriers with versatile characteristics and controlled release properties for the delivery of a wide range of drugs. The microsponges will provide an optimized therapeutic effect, when delivered at the site of action without rupturing, then releasing the cargo at the predetermined time and area. The ability of the microsponges to effectively deliver the drug in a controlled manner depends on the material composition. This comprehensive review entails knowledge on the design parameters of an optimized microsponge drug delivery system and the controlled release properties of microsponges that reduces the side effects of drugs. Furthermore, the review delves into the fabrication techniques of microsponges, the mechanism of drug release from the microsponges, and the regulatory requirements of the U.S. Food and Drug Administration (FDA) for the successful marketing of microsponge formulation. The review also examines the patented formulations of microsponges. The prospects of these sophisticated drug delivery systems for improved clinical outcomes are highlighted.

LncRNAs: the good, the bad, and the unknown

Long non-coding RNAs (lncRNAs) are significant contributors in maintaining genomic integrity through epigenetic regulation. LncRNAs can interact with chromatin-modifying complexes in both cis and trans pathways, drawing them to specific genomic loci and influencing gene expression via DNA methylation, histone modifications, and chromatin remodeling. They can also operate as building blocks to assemble different chromatin-modifying components, facilitating their interactions and gene regulatory functions. Deregulation of these molecules has been associated with various human diseases, including cancer, cardiovascular disease, and neurological disorders. Thus, lncRNAs are implicated as potential diagnostic indicators and therapeutic targets. This review discusses the current understanding of how lncRNAs mediate epigenetic control, genomic integrity, and their putative functions in disease pathogenesis.

Biomimetic Mineralized CRISPR/Cas RNA Nanoparticles for Efficient Tumor-Specific Multiplex Gene Editing

CRISPR/Cas9 systems have great potential to achieve sophisticated gene therapy and cell engineering by editing multiple genomic loci. However, to achieve efficient multiplex gene editing, the delivery system needs adequate capacity to transfect all CRISPR/Cas9 RNA species at the required stoichiometry into the cytosol of each individual cell. Herein, inspired by biomineralization in nature, we develop an all-in-one biomimetic mineralized CRISPR/Cas9 RNA delivery system. This system allows for precise control over the coencapsulation ratio between Cas9 mRNA and multiple sgRNAs, while also exhibiting a high RNA loading capacity. In addition, it enhances the storage stability of RNA at 4 °C for up to one month, and the surface of the nanoparticles can be easily functionalized for precise targeting of RNA nanoparticles in vivo at nonliver sites. Based on the above characteristics, as a proof-of-concept, our system was able to achieve significant gene-editing at each target gene (Survivin: 31.9%, PLK1: 24.41%, HPV: 23.2%) and promote apoptosis of HeLa cells in the mouse model, inhibiting tumor growth without obvious off-target effects in liver tissue. This system addresses various challenges associated with multicomponent RNA delivery in vivo, providing an innovative strategy for the RNA-based CRISPR/Cas9 gene editing.

Modulating Lysosomal pH through Innovative Multimerized Succinic Acid-Based Nucleolipid Derivatives

The multimerization of active compounds has emerged as a successful approach, mainly to address the multivalency of numerous biological targets. Regarding the pharmaceutical prospect, carrying several active ingredient units on the same synthetic scaffold was a practical approach to enhance drug delivery or biological activity with a lower global concentration. Various examples have highlighted better in vivo stability and therapeutic efficiency through sustained action over monomeric molecules. The synthesis strategy aims to covalently connect biologically active monomers to a central core using simple and efficient reaction steps. Despite extensive studies reporting carbohydrate or even peptide multimerization developed for therapeutic activities, very few are concerned with nucleic acid derivatives. In the context of our efforts to build non-viral nucleolipid (NL)-based nanocarriers to restore lysosomal acidification defects, we report here a straightforward synthesis of tetrameric NLs, designed as prodrugs that are able to release no more than one but four biocompatible succinic acid units. The use of oil-in-water nanoemulsion-type vehicles allowed the development of lipid nanosystems crossing the membranes of human neuroblastoma cells. Biological evaluations have proved the effective release of the acid within the lysosome of a genetic and cellular model of Parkinson's disease through the recovery of an optimal lysosomal pH associated with a remarkably fourfold lower concentration of active ingredients than with the corresponding monomers. Overall, these results suggest the feasibility, the therapeutic opportunity, and the better tolerance of multimeric compounds compared to only monomer molecules.