Delivery of RNAs to Specific Organs by Lipid Nanoparticles for Gene Therapy

Systematic Review of Genetic Substrate Reduction Therapy in Lysosomal Storage Diseases: Opportunities, Challenges and Delivery Systems

BACKGROUND

Genetic substrate reduction therapy (gSRT), which involves the use of nucleic acids to downregulate the genes involved in the biosynthesis of storage substances, has been investigated in the treatment of lysosomal storage diseases (LSDs).

OBJECTIVE

To analyze the application of gSRT to the treatment of LSDs, identifying the silencing tools and delivery systems used, and the main challenges for its development and clinical translation, highlighting the contribution of nanotechnology to overcome them.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines was performed. PubMed, Scopus, and Web of Science databases were used for searching terms related to LSDs and gene-silencing strategies and tools.

RESULTS

Fabry, Gaucher, and Pompe diseases and mucopolysaccharidoses I and III are the only LSDs for which gSRT has been studied, siRNA and lipid nanoparticles being the silencing strategy and the delivery system most frequently employed, respectively. Only in one recently published study was CRISPR/Cas9 applied to treat Fabry disease. Specific tissue targeting, availability of relevant cell and animal LSD models, and the rare disease condition are the main challenges with gSRT for the treatment of these diseases. Out of the 11 studies identified, only two gSRT studies were evaluated in animal models.

CONCLUSIONS

Nucleic acid therapies are expanding the clinical tools and therapies currently available for LSDs. Recent advances in CRISPR/Cas9 technology and the growing impact of nanotechnology are expected to boost the clinical translation of gSRT in the near future, and not only for LSDs.

Biodistribution of lipid nanoparticle, eGFP mRNA and translated protein following subcutaneous administration in mouse

Aim: Increased knowledge of biodistribution and pharmacokinetics of lipid nanoparticle (LNP)-encapsulated mRNA drug components may aid efficacy and safety evaluation. Methods: Mice were subcutaneously administrated LNP encapsulated enhanced green fluorescent protein mRNA and sampled up to 72 h after dosing. LNP, mRNA and translated protein were quantified by LC-MS, branched DNA and ELISA. Results: Highest levels of LNP and mRNA were detected in skin, followed by spleen, but also rapidly distributed to circulation. Translated protein showed high concentration in skin and spleen, but also in liver and kidney across 24 h where the LNP was cleared at 4 h. Conclusion: Subcutaneously dosing LNP encapsulated mRNA in mice resulted in a nonlinear relationship of LNP, mRNA and protein concentration across multiple tissues.

Unlocking the Therapeutic Applicability of LNP-mRNA: Chemistry, Formulation, and Clinical Strategies

Messenger RNA (mRNA) has emerged as an innovative therapeutic modality, offering promising avenues for the prevention and treatment of a variety of diseases. The tremendous success of mRNA vaccines in effectively combatting coronavirus disease 2019 (COVID-19) evidences the unlimited medical and therapeutic potential of mRNA technology. Overcoming challenges related to mRNA stability, immunogenicity, and precision targeting has been made possible by recent advancements in lipid nanoparticles (LNPs). This review summarizes state-of-the-art LNP-mRNA-based therapeutics, including their structure, material compositions, design guidelines, and screening principles. Additionally, we highlight current preclinical and clinical trends in LNP-mRNA therapeutics in a broad range of treatments in ophthalmological conditions, cancer immunotherapy, gene editing, and rare-disease medicine. Particular attention is given to the translation and evolution of LNP-mRNA vaccines into a broader spectrum of therapeutics. We explore concerns in the aspects of inadequate extrahepatic targeting efficacy, elevated doses, safety concerns, and challenges of large-scale production procedures. This discussion may offer insights and perspectives on near- and long-term clinical development prospects for LNP-mRNA therapeutics.

Emerging Perspectives on Prime Editor Delivery to the Brain

Prime editing shows potential as a precision genome editing technology, as well as the potential to advance the development of next-generation nanomedicine for addressing neurological disorders. However, turning in prime editors (PEs), which are macromolecular complexes composed of CRISPR/Cas9 nickase fused with a reverse transcriptase and a prime editing guide RNA (pegRNA), to the brain remains a considerable challenge due to physiological obstacles, including the blood-brain barrier (BBB). This review article offers an up-to-date overview and perspective on the latest technologies and strategies for the precision delivery of PEs to the brain and passage through blood barriers. Furthermore, it delves into the scientific significance and possible therapeutic applications of prime editing in conditions related to neurological diseases. It is targeted at clinicians and clinical researchers working on advancing precision nanomedicine for neuropathologies.

What's in a cure: designing a broad-spectrum HIV gene therapy

PURPOSE OF REVIEW

The leading gene editing strategy for a human immunodeficiency virus type 1 (HIV-1) cure involves the delivery of SaCas9 and two guide RNAs (gRNAs) in an adeno-associated viral (AAV) vector. As a dual-component system, CRISPR is targeted to a genetic locus through the choice of a Cas effector and gRNA protospacer design pair. As CRISPR research has expanded in recent years, these components have been investigated for utilization in cure strategies, which will be discussed in this article.

RECENT FINDINGS

Type II SpCas9 and SaCas9 have been the leading Cas effectors across gene editing therapeutics to date. Additionally, extensive research has expanded the potential to multiplex gRNAs and target them effectively to the highly genetically diverse HIV-1 provirus. More recently, the Type V family of Cas12 effectors opens a new opportunity to use a smaller Cas protein for packaging into an AAV vector with multiplexed gRNAs.

SUMMARY

In understanding the individual components of a CRISPR/Cas therapeutic cure for HIV-1, it is important to know that the currently used strategies can be improved upon. Future areas will include alternative smaller Cas effectors, multiplexed gRNAs designs, and/or alternative delivery modalities.

Optimizing Nucleic Acid Delivery Systems through Barcode Technology

Conventional biological experiments often focus on in vitro assays because of the inherent limitations when handling multiple variables in vivo, including labor-intensive and time-consuming procedures. Often only a subset of samples demonstrating significant efficacy in the in vitro assays can be evaluated in vivo. Nonetheless, because of the low correlation between the in vitro and in vivo tests, evaluation of the variables under examination in vivo and not solely in vitro is critical. An emerging approach to achieve high-throughput in vivo tests involves using a barcode system consisting of various nucleotide combinations. Unique barcodes for each variant enable the simultaneous testing of multiple entities, eliminating the need for separate individual tests. Subsequently, to identify crucial parameters, samples were collected and analyzed using barcode sequencing. This review explores the development of barcode design and its applications, including the evaluation of nucleic acid delivery systems and the optimization of gene expression in vivo.

In Situ Reprogramming of Immune Cells Using Synthetic Nanomaterials

In the past decade, adoptive cell therapy with chimeric antigen receptor-T (CAR-T) cells has revolutionized cancer treatment. However, the complexity and high costs involved in manufacturing current adoptive cell therapy greatly inhibit its widespread availability and access. To address this, in situ cell therapy, which directly reprograms immune cells inside the body, has recently been developed as a promising alternative. Here, an overview of the recent progress in the development of synthetic nanomaterials is provided to deliver plasmid DNA or mRNA for in situ reprogramming of T cells and macrophages, focusing especially on in situ CAR therapies. Also, the main challenges for in situ immune cell reprogramming are discussed and some approaches to overcome these barriers to fulfill the clinical applications are proposed.

IL7 increases targeted lipid nanoparticle-mediated mRNA expression in T cells in vitro and in vivo by enhancing T cell protein translation

The use of lipid nanoparticles (LNP) to encapsulate and deliver mRNA has become an important therapeutic advance. In addition to vaccines, LNP-mRNA can be used in many other applications. For example, targeting the LNP with anti-CD5 antibodies (CD5/tLNP) can allow for efficient delivery of mRNA payloads to T cells to express protein. As the percentage of protein expressing T cells induced by an intravenous injection of CD5/tLNP is relatively low (4-20%), our goal was to find ways to increase mRNA-induced translation efficiency. We showed that T cell activation using an anti-CD3 antibody improved protein expression after CD5/tLNP transfection in vitro but not in vivo. T cell health and activation can be increased with cytokines, therefore, using mCherry mRNA as a reporter, we found that culturing either mouse or human T cells with the cytokine IL7 significantly improved protein expression of delivered mRNA in both CD4+ and CD8+ T cells in vitro. By pre-treating mice with systemic IL7 followed by tLNP administration, we observed significantly increased mCherry protein expression by T cells in vivo. Transcriptomic analysis of mouse T cells treated with IL7 in vitro revealed enhanced genomic pathways associated with protein translation. Improved translational ability was demonstrated by showing increased levels of protein expression after electroporation with mCherry mRNA in T cells cultured in the presence of IL7, but not with IL2 or IL15. These data show that IL7 selectively increases protein translation in T cells, and this property can be used to improve expression of tLNP-delivered mRNA in vivo.

tRNA therapeutics for genetic diseases

Transfer RNAs (tRNAs) have a crucial role in protein synthesis, and in recent years, their therapeutic potential for the treatment of genetic diseases - primarily those associated with a mutation altering mRNA translation - has gained significant attention. Engineering tRNAs to readthrough nonsense mutation-associated premature termination of mRNA translation can restore protein synthesis and function. In addition, supplementation of natural tRNAs can counteract effects of missense mutations in proteins crucial for tRNA biogenesis and function in translation. This Review will present advances in the development of tRNA therapeutics with high activity and safety in vivo and discuss different formulation approaches for single or chronic treatment modalities. The field of tRNA therapeutics is still in its early stages, and a series of challenges related to tRNA efficacy and stability in vivo, delivery systems with tissue-specific tropism, and safe and efficient manufacturing need to be addressed.

Self-delivering, chemically modified CRISPR RNAs for AAV co-delivery and genome editing in vivo

Guide RNAs offer programmability for CRISPR-Cas9 genome editing but also add challenges for delivery. Chemical modification, which has been key to the success of oligonucleotide therapeutics, can enhance the stability, distribution, cellular uptake, and safety of nucleic acids. Previously, we engineered heavily and fully modified SpyCas9 crRNA and tracrRNA, which showed enhanced stability and retained activity when delivered to cultured cells in the form of the ribonucleoprotein complex. In this study, we report that a short, fully stabilized oligonucleotide (a 'protecting oligo'), which can be displaced by tracrRNA annealing, can significantly enhance the potency and stability of a heavily modified crRNA. Furthermore, protecting oligos allow various bioconjugates to be appended, thereby improving cellular uptake and biodistribution of crRNA in vivo. Finally, we achieved in vivo genome editing in adult mouse liver and central nervous system via co-delivery of unformulated, chemically modified crRNAs with protecting oligos and AAV vectors that express tracrRNA and either SpyCas9 or a base editor derivative. Our proof-of-concept establishment of AAV/crRNA co-delivery offers a route towards transient editing activity, target multiplexing, guide redosing, and vector inactivation.

Quaternization drives spleen-to-lung tropism conversion for mRNA-loaded lipid-like nanoassemblies

Background: As the overwhelming majority of advanced mRNA delivery systems are preferentially accumulated in the liver, there is an accelerating growth in the demand for the development of non-liver mRNA delivery platforms. Methods: In this study, we prepared cationic lipid-like nanoassemblies through a N-quaternizing strategy. Their physicochemical properties, in vitro mRNA delivery efficiency, and organ tropism in mice were investigated. Results: Introduction of quaternary ammonium groups onto lipid-like nanoassemblies not only enhances their mRNA delivery performance in vitro, but also completely alters their tropism from the spleen to the lung after intravenous administration in mice. Quaternized lipid-like nanoassemblies exhibit ultra-high specificity to the lung and are predominantly taken up by pulmonary immune cells, leading to over 95% of exogenous mRNA translation in the lungs. Such mRNA delivery carriers are stable even after more than one-year storage at ambient temperature. Conclusions: Quaternization provides an alternative method for design of new lung-targeted mRNA delivery systems without incorporation of targeting ligands, which should extend the therapeutic applicability of mRNA to lung diseases.

A Lipid Nanoparticle-Based Method for the Generation of Liver-Specific Knockout Mice

Knockout mice are useful tools that can provide information about the normal function of genes, including their biochemical, developmental, and physiological roles. One problem associated with the generation of knockout mice is that the loss of some genes of interest produces a lethal phenotype. Therefore, the use of conditioned knockout mice, in which genes are disrupted in specific organs, is essential for the elucidation of disease pathogenesis and the verification of drug targets. In general, conditional knockout mice are produced using the Cre/loxP system; however, the production of the large numbers of Cre/flox knockout and control mice required for analysis requires substantial time and effort. Here, we describe the generation of liver-specific conditional knockout mice via the introduction of lipid nanoparticles encapsulating Cre mRNA into the liver of floxed mice. This technique does not require the production of offspring by mating floxed mice and is therefore more convenient than the conventional method. The results presented here demonstrate that the LNP-based method enables liver-specific gene knockout in a short period of time.

Evolution of nanomedicine formulations for targeted delivery and controlled release

Nanotechnology research over the past several decades has been aimed primarily at improving the physicochemical properties of small molecules to produce druggable candidates as well as for tumor targeting of cytotoxic molecules. The recent focus on genomic medicine and the success of lipid nanoparticles for mRNA vaccines have provided additional impetus for the development of nanoparticle drug carriers for nucleic acid delivery, including siRNA, mRNA, DNA, and oligonucleotides, to create therapeutics that can modulate protein deregulation. Bioassays and characterizations, including trafficking assays, stability, and endosomal escape, are key to understanding the properties of these novel nanomedicine formats. We review historical nanomedicine platforms, characterization methodologies, challenges to their clinical translation, and key quality attributes for commercial translation with a view to their developability into a genomic medicine. New nanoparticle systems for immune targeting, as well as in vivo gene editing and in situ CAR therapy, are also highlighted as emerging areas.

Delivery of Lipid Nanoparticles with ROS Probes for Improved Visualization of Hepatocellular Carcinoma

Reactive oxygen species (ROS) are highly reactive products of the cell metabolism derived from oxygen molecules, and their abundant level is observed in many diseases, particularly tumors, such as hepatocellular carcinoma (HCC). In vivo imaging of ROS is a necessary tool in preclinical research to evaluate the efficacy of drugs with antioxidant activity and for diagnosis and monitoring of diseases. However, most known sensors cannot be used for in vivo experiments due to low stability in the blood and rapid elimination from the body. In this work, we focused on the development of an effective delivery system of fluorescent probes for intravital ROS visualization using the HCC model. We have synthesized various lipid nanoparticles (LNPs) loaded with ROS-inducible hydrocyanine pro-fluorescent dye or plasmid DNA (pDNA) with genetically encoded protein sensors of hydrogen peroxide (HyPer7). LNP with an average diameter of 110 ± 12 nm, characterized by increased stability and pDNA loading efficiency (64 ± 7%), demonstrated preferable accumulation in the liver compared to 170 nm LNPs. We evaluated cytotoxicity and demonstrated the efficacy of hydrocyanine-5 and HyPer7 formulated in LNP for ROS visualization in mouse hepatocytes (AML12 cells) and in the mouse xenograft model of HCC. Our results demonstrate that obtained LNP could be a valuable tool in preclinical research for visualization ROS in liver diseases.

Prime Editing for Human Gene Therapy: Where Are We Now?

Gene therapy holds tremendous potential in the treatment of inherited diseases. Unlike traditional medicines, which only treat the symptoms, gene therapy has the potential to cure the disease by addressing the root of the problem: genetic mutations. The discovery of CRISPR/Cas9 in 2012 paved the way for the development of those therapies. Improvement of this system led to the recent development of an outstanding technology called prime editing. This system can introduce targeted insertions, deletions, and all 12 possible base-to-base conversions in the human genome. Since the first publication on prime editing in 2019, groups all around the world have worked on this promising technology to develop a treatment for genetic diseases. To date, prime editing has been attempted in preclinical studies for liver, eye, skin, muscular, and neurodegenerative hereditary diseases, in addition to cystic fibrosis, beta-thalassemia, X-linked severe combined immunodeficiency, and cancer. In this review, we portrayed where we are now on prime editing for human gene therapy and outlined the best strategies for correcting pathogenic mutations by prime editing.

Biodrug Delivery Systems: Do mRNA Lipid Nanoparticles Come of Age?

As an appealing alternative to treat and prevent diseases ranging from cancer to COVID-19, mRNA has demonstrated significant clinical effects. Nanotechnology facilitates the successful implementation of the systemic delivery of mRNA for safe human consumption. In this manuscript, we provide an overview of current mRNA therapeutic applications and discuss key biological barriers to delivery and recent advances in the development of nonviral systems. The relevant challenges that LNPs face in achieving cost-effective and widespread clinical implementation when delivering mRNA are likewise discussed.

The interplay between cardiac dyads and mitochondria regulated the calcium handling in cardiomyocytes

Calcium mishandling and mitochondrial dysfunction have been increasingly recognized as significant factors involved in the progression procedure of cardiomyopathy. Ca2+ mishandling could cause calcium-triggered arrhythmias, which could enhance force development and ATP consumption. Mitochondrial disorganization and dysfunction in cardiomyopathy could disturb the balance of energy catabolic and anabolic procedure. Close spatial localization and arrangement of structural among T-tubule, sarcoplasmic reticulum, mitochondria are important for Ca2+ handling. So that, we illustrate the regulating network between calcium handling and mitochondrial homeostasis, as well as its intracellular mechanisms in this review, which would be worthy to develop novel therapeutic strategy and restore the function of injured cardiomyocytes.