In vivo hematopoietic stem cell modification by mRNA delivery

Lung-specific supramolecular nanoparticles for efficient delivery of therapeutic proteins and genome editing nucleases

Protein therapeutics play a critical role in treating a large variety of diseases, ranging from infections to genetic disorders. However, their delivery to target tissues beyond the liver, such as the lungs, remains a great challenge. Here, we report a universally applicable strategy for lung-targeted protein delivery by engineering Lung-Specific Supramolecular Nanoparticles (LSNPs). These nanoparticles are designed through the hierarchical self-assembly of metal-organic polyhedra (MOP), featuring a customized surface chemistry that enables protein encapsulation and specific lung affinity after intravenous administration. Our design of LSNPs not only addresses the hurdles of cell membrane impermeability of protein and nonspecific tissue distribution of protein delivery, but also shows exceptional versatility in delivering various proteins, including those vital for anti-inflammatory and CRISPR-based genome editing to the lung, and across multiple animal species, including mice, rabbits, and dogs. Notably, the delivery of antimicrobial proteins using LSNPs effectively alleviates acute bacterial pneumonia, demonstrating a significant therapeutic potential. Our strategy not only surmounts the obstacles of tissue-specific protein delivery but also paves the way for targeted treatments in genetic disorders and combating antibiotic resistance, offering a versatile solution for precision protein therapy.

In utero delivery of targeted ionizable lipid nanoparticles facilitates in vivo gene editing of hematopoietic stem cells

Monogenic blood diseases are among the most common genetic disorders worldwide. These diseases result in significant pediatric and adult morbidity, and some can result in death prior to birth. Novel ex vivo hematopoietic stem cell (HSC) gene editing therapies hold tremendous promise to alter the therapeutic landscape but are not without potential limitations. In vivo gene editing therapies offer a potentially safer and more accessible treatment for these diseases but are hindered by a lack of delivery vectors targeting HSCs, which reside in the difficult-to-access bone marrow niche. Here, we propose that this biological barrier can be overcome by taking advantage of HSC residence in the easily accessible liver during fetal development. To facilitate the delivery of gene editing cargo to fetal HSCs, we developed an ionizable lipid nanoparticle (LNP) platform targeting the CD45 receptor on the surface of HSCs. After validating that targeted LNPs improved messenger ribonucleic acid (mRNA) delivery to hematopoietic lineage cells via a CD45-specific mechanism in vitro, we demonstrated that this platform mediated safe, potent, and long-term gene modulation of HSCs in vivo in multiple mouse models. We further optimized this LNP platform in vitro to encapsulate and deliver CRISPR-based nucleic acid cargos. Finally, we showed that optimized and targeted LNPs enhanced gene editing at a proof-of-concept locus in fetal HSCs after a single in utero intravenous injection. By targeting HSCs in vivo during fetal development, our Systematically optimized Targeted Editing Machinery (STEM) LNPs may provide a translatable strategy to treat monogenic blood diseases before birth.

Advances in the development of lipid nanoparticles for ophthalmic therapeutics

Previously, researchers have employed Lipid nanoparticles (LNPs) to directly encapsulate medicines. In the realm of gene therapy, researchers have begun to employ lipid nanoparticles to encapsulate nucleic acids such as messenger RNA, small interfering RNA, and plasmid DNA, which are known as nucleic acid lipid nanoparticles. Recent breakthroughs in LNP-based medicine have provided significant prospects for the treatment of ocular disorders, such as corneal, choroidal, and retinal diseases. The use of LNP as a delivery mechanism for medicines and therapeutic genes can increase their effectiveness while avoiding undesired immune reactions. However, LNP-based medicines may pose ocular concerns. In this review, we discuss the general framework of LNP. Additionally, we review adjustable approaches and evaluate their possible risks. In addition, we examine newly described ocular illnesses in which LNP was utilized as a delivery mechanism. Finally, we provide perspectives for solving these potential issues.

Reformulating lipid nanoparticles for organ-targeted mRNA accumulation and translation

Fully targeted mRNA therapeutics necessitate simultaneous organ-specific accumulation and effective translation. Despite some progress, delivery systems are still unable to fully achieve this. Here, we reformulate lipid nanoparticles (LNPs) through adjustments in lipid material structures and compositions to systematically achieve the pulmonary and hepatic (respectively) targeted mRNA distribution and expression. A combinatorial library of degradable-core based ionizable cationic lipids is designed, following by optimisation of LNP compositions. Contrary to current LNP paradigms, our findings demonstrate that cholesterol and phospholipid are dispensable for LNP functionality. Specifically, cholesterol-removal addresses the persistent challenge of preventing nanoparticle accumulation in hepatic tissues. By modulating and simplifying intrinsic LNP components, concurrent mRNA accumulation and translation is achieved in the lung and liver, respectively. This targeting strategy is applicable to existing LNP systems with potential to expand the progress of precise mRNA therapy for diverse diseases.

The 60-year evolution of lipid nanoparticles for nucleic acid delivery

Delivery of genetic information to the interior of target cells in vivo has been a major challenge facing gene therapies. This barrier is now being overcome, owing in part to dramatic advances made by lipid-based systems that have led to lipid nanoparticles (LNPs) that enable delivery of nucleic acid-based vaccines and therapeutics. Examples include the clinically approved COVID-19 LNP mRNA vaccines and Onpattro (patisiran), an LNP small interfering RNA therapeutic to treat transthyretin-induced amyloidosis (hATTR). In addition, a host of promising LNP-enabled vaccines and gene therapies are in clinical development. Here, we trace this success to two streams of research conducted over the past 60 years: the discovery of the transfection properties of lipoplexes composed of positively charged cationic lipids complexed with nucleic acid cargos and the development of lipid nanoparticles using ionizable cationic lipids. The fundamental insights gained from these two streams of research offer potential delivery solutions for most forms of gene therapies.

Bone marrow Tfr2 deletion improves the therapeutic efficacy of the activin-receptor ligand trap RAP-536 in β-thalassemic mice

β-thalassemia is a disorder characterized by anemia, ineffective erythropoiesis (IE), and iron overload, whose treatment still requires improvement. The activin receptor-ligand trap Luspatercept, a novel therapeutic option for β-thalassemia, stimulates erythroid differentiation inhibiting the transforming growth factor β pathway. However, its exact mechanism of action and the possible connection with erythropoietin (Epo), the erythropoiesis governing cytokine, remain to be clarified. Moreover, Luspatercept does not correct all the features of the disease, calling for the identification of strategies that enhance its efficacy. Transferrin receptor 2 (TFR2) regulates systemic iron homeostasis in the liver and modulates the response to Epo of erythroid cells, thus balancing red blood cells production with iron availability. Stimulating Epo signaling, hematopoietic Tfr2 deletion ameliorates anemia and IE in Hbbth3/+ thalassemic mice. To investigate whether hematopoietic Tfr2 inactivation improves the efficacy of Luspatercept, we treated Hbbth3/+ mice with or without hematopoietic Tfr2 (Tfr2BMKO/Hbbth3/+) with RAP-536, the murine analog of Luspatercept. As expected, both hematopoietic Tfr2 deletion and RAP-536 significantly ameliorate IE and anemia, and the combined approach has an additive effect. Since RAP-536 has comparable efficacy in both Hbbth3/+ and Tfr2BMKO/Hbbth3/+ animals, we propose that the drug promotes erythroid differentiation independently of TFR2 and EPO stimulation. Notably, the lack of Tfr2, but not RAP-536, can also attenuate iron-overload and related complications. Overall, our results shed further light on the mechanism of action of Luspatercept and suggest that strategies aimed at inhibiting hematopoietic TFR2 might improve the therapeutic efficacy of activin receptor-ligand traps.

The CRISPR-Cas System and Clinical Applications of CRISPR-Based Gene Editing in Hematology with a Focus on Inherited Germline Predisposition to Hematologic Malignancies

Clustered regularly interspaced short palindromic repeats (CRISPR)-based gene editing has begun to transform the treatment landscape of genetic diseases. The history of the discovery of CRISPR/CRISPR-associated (Cas) proteins/single-guide RNA (sgRNA)-based gene editing since the first report of repetitive sequences of unknown significance in 1987 is fascinating, highly instructive, and inspiring for future advances in medicine. The recent approval of CRISPR-Cas9-based gene therapy to treat patients with severe sickle cell anemia and transfusion-dependent β-thalassemia has renewed hope for treating other hematologic diseases, including patients with a germline predisposition to hematologic malignancies, who would benefit greatly from the development of CRISPR-inspired gene therapies. The purpose of this paper is three-fold: first, a chronological description of the history of CRISPR-Cas9-sgRNA-based gene editing; second, a brief description of the current state of clinical research in hematologic diseases, including selected applications in treating hematologic diseases with CRISPR-based gene therapy, preceded by a brief description of the current tools being used in clinical genome editing; and third, a presentation of the current progress in gene therapies in inherited hematologic diseases and bone marrow failure syndromes, to hopefully stimulate efforts towards developing these therapies for patients with inherited bone marrow failure syndromes and other inherited conditions with a germline predisposition to hematologic malignancies.

EGFR-targeted ionizable lipid nanoparticles enhance in vivo mRNA delivery to the placenta

The full potential of ionizable lipid nanoparticles (LNPs) as an in vivo nucleic acid delivery platform has not yet been realized given that LNPs primarily accumulate in the liver following systemic administration, limiting their success to liver-centric conditions. The engineering of LNPs with antibody targeting moieties can enable extrahepatic tropism by facilitating site-specific LNP tethering and driving preferential LNP uptake into receptor-expressing cell types via receptor-mediated endocytosis. Obstetric conditions stemming from placental dysfunction, such as preeclampsia, are characterized by overexpression of cellular receptors, including the epidermal growth factor receptor (EGFR), making targeted LNP platforms an exciting potential treatment strategy for placental dysfunction during pregnancy. Herein, an EGFR antibody-conjugated LNP (aEGFR-LNP) platform was developed by engineering LNPs with increasing densities of antibody functionalization. aEGFR-LNPs were screened in vitro in immortalized placental trophoblasts and in vivo in non-pregnant and pregnant mice and compared to non-targeted formulations for extrahepatic, antibody-targeted mRNA LNP delivery to the placenta. Our top performing LNP with an intermediate density of antibody functionalization (1:5 aEGFR-LNP) mediated a ∼twofold increase in mRNA delivery in murine placentas and a ∼twofold increase in LNP uptake in EGFR-expressing trophoblasts compared to non-targeted counterparts. These results demonstrate the potential of antibody-conjugated LNPs for achieving extrahepatic tropism, and the ability of aEGFR-LNPs in promoting mRNA delivery to EGFR-expressing cell types in the placenta.

iPS cell therapy 2.0: Preparing for next-generation regenerative medicine

This year marks the tenth anniversary of the world's first transplantation of tissue generated from induced pluripotent stem cells (iPSCs). There is now a growing number of clinical trials worldwide examining the efficacy and safety of autologous and allogeneic iPSC-derived products for treating various pathologic conditions. As we patiently wait for the results from these and future clinical trials, it is imperative to strategize for the next generation of iPSC-based therapies. This review examines the lessons learned from the development of another advanced cell therapy, chimeric antigen receptor (CAR) T cells, and the possibility of incorporating various new bioengineering technologies in development, from RNA engineering to tissue fabrication, to apply iPSCs not only as a means to achieve personalized medicine but also as designer medical applications.

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.

siRNA-mediated reduction of a circulating protein in swine using lipid nanoparticles

Genetic manipulation of animal models is a fundamental research tool in biology and medicine but is challenging in large animals. In rodents, models can be readily developed by knocking out genes in embryonic stem cells or by knocking down genes through in vivo delivery of nucleic acids. Swine are a preferred animal model for studying the cardiovascular and immune systems, but there are limited strategies for genetic manipulation. Lipid nanoparticles (LNPs) efficiently deliver small interfering RNA (siRNA) to knock down circulating proteins, but swine are sensitive to LNP-induced complement activation-related pseudoallergy (CARPA). We hypothesized that appropriately administering optimized siRNA-LNPs could knock down circulating levels of plasminogen, a blood protein synthesized in the liver. siRNA-LNPs against plasminogen (siPLG) reduced plasma plasminogen protein and hepatic plasminogen mRNA levels to below 5% of baseline values. Functional assays showed that reducing plasminogen levels modulated systemic blood coagulation. Clinical signs of CARPA were not observed, and occasional mild and transient hepatotoxicity was present in siPLG-treated animals at 5 h post-infusion, which returned to baseline by 7 days. These findings advance siRNA-LNPs in swine models, enabling genetic engineering of blood and hepatic proteins, which can likely expand to proteins in other tissues in the future.

Peptide-encoding gene transfer to modulate intracellular protein-protein interactions

Peptide drug discovery has great potential, but the cell membrane is a major obstacle when the target is an intracellular protein-protein interaction (PPI). It is difficult to target PPIs with small molecules; indeed, there are no intervention tools that can target any intracellular PPI. In this study, we developed a platform that enables the introduction of peptides into cells via mRNA-based gene delivery. Peptide-length nucleic acids do not enable stable ribosome binding and exhibit little to no translation into protein. In this study, a construct was created in which the sequence encoding dihydrofolate reductase (DHFR) was placed in front of the sequence encoding the target peptide, together with a translation skipping sequence, as a sequence that meets the requirements of promoting ribosome binding and rapid decay of the translated protein. This enabled efficient translation from the mRNA encoding the target protein while preventing unnecessary protein residues. Using this construct, we showed that it can inhibit Drp1/Fis1 binding, one of the intracellular PPIs, which governs mitochondrial fission, an important aspect of mitochondrial dynamics. In addition, it was shown to inhibit pathological hyperfission, normalize mitochondrial dynamics and metabolism, and inhibit apoptosis of the mitochondrial pathway.

Strategies for enhanced gene delivery to the central nervous system

The delivery of genes to the central nervous system (CNS) has been a persistent challenge due to various biological barriers. The blood-brain barrier (BBB), in particular, hampers the access of systemically injected drugs to parenchymal cells, allowing only a minimal percentage (<1%) to pass through. Recent scientific insights highlight the crucial role of the extracellular space (ECS) in governing drug diffusion. Taking into account advancements in vectors, techniques, and knowledge, the discussion will center on the most notable vectors utilized for gene delivery to the CNS. This review will explore the influence of the ECS - a dynamically regulated barrier-on drug diffusion. Furthermore, we will underscore the significance of employing remote-control technologies to facilitate BBB traversal and modulate the ECS. Given the rapid progress in gene editing, our discussion will also encompass the latest advances focused on delivering therapeutic editing in vivo to the CNS tissue. In the end, a brief summary on the impact of Artificial Intelligence (AI)/Machine Learning (ML), ultrasmall, soft endovascular robots, and high-resolution endovascular cameras on improving the gene delivery to the CNS will be provided.

Helper Lipid-Enhanced mRNA Delivery for Treating Metabolic Dysfunction-Associated Fatty Liver Disease

Lipid nanoparticles (LNPs) represent the forefront of mRNA delivery platforms, yet achieving precise delivery to specific cells remains a challenge. The current targeting strategies complicate the formulation and impede the regulatory approval process. Here, through a straightforward regulation of helper lipids within LNPs, we introduce an engineered LNP designed for targeted delivery of mRNA into hepatocytes for metabolic dysfunction-associated fatty liver disease (MAFLD) treatment. The optimized LNP, supplied with POPC as the helper lipid, exhibits a 2.49-fold increase in mRNA transfection efficiency in hepatocytes compared to that of FDA-approved LNPs. CTP:phosphocholine cytidylyltransferase α mRNA is selected for delivery to hepatocytes through the optimized LNP system for self-calibration of phosphatidylcholine levels to prevent lipid droplet expansion in MAFLD. This strategy effectively regulates lipid homeostasis, while demonstrating proven biosafety. Our results present a mRNA therapy for MAFLD and open a new avenue for discovering potent lipids enabling mRNA delivery to specific cells.

Frameworks for transformational breakthroughs in RNA-based medicines

RNA has sparked a revolution in modern medicine, with the potential to transform the way we treat diseases. Recent regulatory approvals, hundreds of new clinical trials, the emergence of CRISPR gene editing, and the effectiveness of mRNA vaccines in dramatic response to the COVID-19 pandemic have converged to create tremendous momentum and expectation. However, challenges with this relatively new class of drugs persist and require specialized knowledge and expertise to overcome. This Review explores shared strategies for developing RNA drug platforms, including layering technologies, addressing common biases and identifying gaps in understanding. It discusses the potential of RNA-based therapeutics to transform medicine, as well as the challenges associated with improving applicability, efficacy and safety profiles. Insights gained from RNA modalities such as antisense oligonucleotides (ASOs) and small interfering RNAs are used to identify important next steps for mRNA and gene editing technologies.

Advancing in vivo reprogramming with synthetic biology

Reprogramming cells will play a fundamental role in shaping the future of cell therapies by developing new strategies to engineer cells for improved performance and higher-order physiological functions. Approaches in synthetic biology harness cells' natural ability to sense diverse signals, integrate environmental inputs to make decisions, and execute complex behaviors based on the health of the organism or tissue. In this review, we highlight strategies in synthetic biology to reprogram cells, and discuss how recent approaches in the delivery of modified mRNA have created new opportunities to alter cell function in vivo. Finally, we discuss how combining concepts from synthetic biology and the delivery of mRNA in vivo could provide a platform for innovation to advance in vivo cellular reprogramming.

Engineering an Escherichia coli based in vivo mRNA manufacturing platform

Synthetic mRNA is currently produced in standardized in vitro transcription systems. However, this one-size-fits-all approach has associated drawbacks in supply chain shortages, high reagent costs, complex product-related impurity profiles, and limited design options for molecule-specific optimization of product yield and quality. Herein, we describe for the first time development of an in vivo mRNA manufacturing platform, utilizing an Escherichia coli cell chassis. Coordinated mRNA, DNA, cell and media engineering, primarily focussed on disrupting interactions between synthetic mRNA molecules and host cell RNA degradation machinery, increased product yields >40-fold compared to standard "unengineered" E. coli expression systems. Mechanistic dissection of cell factory performance showed that product mRNA accumulation levels approached theoretical limits, accounting for ~30% of intracellular total RNA mass, and that this was achieved via host-cell's reallocating biosynthetic capacity away from endogenous RNA and cell biomass generation activities. We demonstrate that varying sized functional mRNA molecules can be produced in this system and subsequently purified. Accordingly, this study introduces a new mRNA production technology, expanding the solution space available for mRNA manufacturing.

Lipid nanoparticle-based strategies for extrahepatic delivery of nucleic acid therapies - challenges and opportunities

The advent of lipid nanoparticles (LNPs) containing ionizable cationic lipids has enabled the encapsulation, stabilization, and intracellular delivery of nucleic acid payloads, leading to FDA-approved siRNA-based therapy and mRNA-based vaccines. Other nucleic acid-based therapeutic modalities, including protein replacement and CRISPR-mediated gene knockout and editing, are being tested in clinical trials, in many cases, for the treatment of liver-related diseases. However, to fully exploit these therapies beyond the liver, improvements in their delivery to extrahepatic targets are needed. Towards this end, both active targeting strategies based on targeting ligands grafted onto LNPs and passive targeting relying on physicochemical LNP parameters such as surface composition, charge, and size are being evaluated. Often, the latter strategy depends on the interaction of LNPs with blood components, forming what is known as the biomolecular corona. Here, I discuss potential challenges related to current LNP-based targeting strategies and the studies of the biomolecular corona on LNPs. I propose potential solutions to overcome some of these obstacles and present approaches currently being tested in preclinical and clinical studies, which face fewer biological barriers than traditional organ-targeting approaches.

Nucleic acid-based drugs for patients with solid tumours

The treatment of patients with advanced-stage solid tumours typically involves a multimodality approach (including surgery, chemotherapy, radiotherapy, targeted therapy and/or immunotherapy), which is often ultimately ineffective. Nucleic acid-based drugs, either as monotherapies or in combination with standard-of-care therapies, are rapidly emerging as novel treatments capable of generating responses in otherwise refractory tumours. These therapies include those using viral vectors (also referred to as gene therapies), several of which have now been approved by regulatory agencies, and nanoparticles containing mRNAs and a range of other nucleotides. In this Review, we describe the development and clinical activity of viral and non-viral nucleic acid-based treatments, including their mechanisms of action, tolerability and available efficacy data from patients with solid tumours. We also describe the effects of the tumour microenvironment on drug delivery for both systemically administered and locally administered agents. Finally, we discuss important trends resulting from ongoing clinical trials and preclinical testing, and manufacturing and/or stability considerations that are expected to underpin the next generation of nucleic acid agents for patients with solid tumours.

Enhancing prime editing in hematopoietic stem and progenitor cells by modulating nucleotide metabolism

Therapeutic prime editing of hematopoietic stem and progenitor cells (HSPCs) holds great potential to remedy blood disorders. Quiescent cells have low nucleotide levels and resist retroviral infection, and it is possible that nucleotide metabolism could limit reverse transcription-mediated prime editing in HSPCs. We demonstrate that deoxynucleoside supplementation and Vpx-mediated degradation of SAMHD1 improve prime editing efficiency in HSPCs, especially when coupled with editing approaches that evade mismatch repair.

Bone-marrow-homing lipid nanoparticles for genome editing in diseased and malignant haematopoietic stem cells

Therapeutic genome editing of haematopoietic stem cells (HSCs) would provide long-lasting treatments for multiple diseases. However, the in vivo delivery of genetic medicines to HSCs remains challenging, especially in diseased and malignant settings. Here we report on a series of bone-marrow-homing lipid nanoparticles that deliver mRNA to a broad group of at least 14 unique cell types in the bone marrow, including healthy and diseased HSCs, leukaemic stem cells, B cells, T cells, macrophages and leukaemia cells. CRISPR/Cas and base editing is achieved in a mouse model expressing human sickle cell disease phenotypes for potential foetal haemoglobin reactivation and conversion from sickle to non-sickle alleles. Bone-marrow-homing lipid nanoparticles were also able to achieve Cre-recombinase-mediated genetic deletion in bone-marrow-engrafted leukaemic stem cells and leukaemia cells. We show evidence that diverse cell types in the bone marrow niche can be edited using bone-marrow-homing lipid nanoparticles.

dsRNAi-mediated silencing of PIAS2beta specifically kills anaplastic carcinomas by mitotic catastrophe

The E3 SUMO ligase PIAS2 is expressed at high levels in differentiated papillary thyroid carcinomas but at low levels in anaplastic thyroid carcinomas (ATC), an undifferentiated cancer with high mortality. We show here that depletion of the PIAS2 beta isoform with a transcribed double-stranded RNA-directed RNA interference (PIAS2b-dsRNAi) specifically inhibits growth of ATC cell lines and patient primary cultures in vitro and of orthotopic patient-derived xenografts (oPDX) in vivo. Critically, PIAS2b-dsRNAi does not affect growth of normal or non-anaplastic thyroid tumor cultures (differentiated carcinoma, benign lesions) or cell lines. PIAS2b-dsRNAi also has an anti-cancer effect on other anaplastic human cancers (pancreas, lung, and gastric). Mechanistically, PIAS2b is required for proper mitotic spindle and centrosome assembly, and it is a dosage-sensitive protein in ATC. PIAS2b depletion promotes mitotic catastrophe at prophase. High-throughput proteomics reveals the proteasome (PSMC5) and spindle cytoskeleton (TUBB3) to be direct targets of PIAS2b SUMOylation at mitotic initiation. These results identify PIAS2b-dsRNAi as a promising therapy for ATC and other aggressive anaplastic carcinomas.

Matrix metalloproteinase-9 deficiency confers resilience in fibrodysplasia ossificans progressiva in a man and mice

Single case studies of extraordinary disease resilience may provide therapeutic insight into conditions for which no definitive treatments exist. An otherwise healthy 35-year-old man (patient-R) with the canonical pathogenic ACVR1R206H variant and the classic congenital great toe malformation of fibrodysplasia ossificans progressiva (FOP) had extreme paucity of post-natal heterotopic ossification (HO) and nearly normal mobility. We hypothesized that patient-R lacked a sufficient post-natal inflammatory trigger for HO. A plasma biomarker survey revealed a reduction in total matrix metalloproteinase-9 (MMP-9) compared to healthy controls and individuals with quiescent FOP. Whole exome sequencing identified compound heterozygous variants in MMP-9 (c.59C > T, p.A20V and c.493G > A, p.D165N). Structural analysis of the D165N variant predicted both decreased MMP-9 secretion and activity that were confirmed by enzyme-linked immunosorbent assay and gelatin zymography. Further, human proinflammatory M1-like macrophages expressing either MMP-9 variant produced significantly less Activin A, an obligate ligand for HO in FOP, compared to wildtype controls. Importantly, MMP-9 inhibition by genetic, biologic, or pharmacologic means in multiple FOP mouse models abrogated trauma-induced HO, sequestered Activin A in the extracellular matrix (ECM), and induced regeneration of injured skeletal muscle. Our data suggest that MMP-9 is a druggable node linking inflammation to HO, orchestrates an existential role in the pathogenesis of FOP, and illustrates that a single patient's clinical phenotype can reveal critical molecular mechanisms of disease that unveil novel treatment strategies.

Progress in novel delivery technologies to improve efficacy of therapeutic antibodies

Monoclonal antibody-based therapeutics have achieved remarkable success in treating a wide range of human diseases. However, conventional systemic delivery methods have limitations in insufficient target tissue permeability, high costs, repeated administrations, etc. Novel technologies have been developed to address these limitations and further enhance antibody therapy. Local antibody delivery via respiratory tract, gastrointestinal tract, eye and blood-brain barrier have shown promising results in increasing local concentrations and overcoming barriers. Nucleic acid-encoded antibodies expressed from plasmid DNA, viral vectors or mRNA delivery platforms also offer advantages over recombinant proteins such as sustained expression, rapid onset, and lower costs. This review summarizes recent advances in antibody delivery methods and highlights innovative technologies that have potential to expand therapeutic applications of antibodies.

Biomaterial-assisted therapeutic cell production and modification in vivo

Hematopoietic stem cell transplantation remains the preferred treatment for a variety of hematopoietic function disorders. To address the issue of limited numbers of hematopoietic stem/progenitor cells (HSPCs), significant progress has been made in the technology for ex vivo expansion of HSPCs. In addition, biomaterial-assisted in vivo production technology for therapeutic cells, including HSPCs, is gradually gaining attention. With the aid of specifically functional biomaterials, researchers can construct bone-like tissues exhibiting typical bone marrow-like structures (termed in vivo osteo-organoids in this article) for the production of therapeutic cells. These in vivo osteo-organoids mimic the native bone marrow niche and provide a microenvironment conducive to the expansion and differentiation of HSPCs. In this perspective article, we systematically summarize the history of in vivo osteo-organoids as a model for studying hematopoiesis and cancer metastasis and propose the challenges faced by the in vivo osteo-organoid production platform for therapeutic cells in terms of clinical translation. Ultimately, we hope to achieve functional customization of in vivo osteo-organoid-derived cells through continuously developed material design methods, so as to meet the treatment needs of different types of diseases and bring hope for life to more people.

Physiological Barriers and Strategies of Lipid-Based Nanoparticles for Nucleic Acid Drug Delivery

Lipid-based nanoparticles (LBNPs) are currently the most promising vehicles for nucleic acid drug (NAD) delivery. Although their clinical applications have achieved success, the NAD delivery efficiency and safety are still unsatisfactory, which are, to a large extent, due to the existence of multi-level physiological barriers in vivo. It is important to elucidate the interactions between these barriers and LBNPs, which will guide more rational design of efficient NAD vehicles with low adverse effects and facilitate broader applications of nucleic acid therapeutics. This review describes the obstacles and challenges of biological barriers to NAD delivery at systemic, organ, sub-organ, cellular, and subcellular levels. The strategies to overcome these barriers are comprehensively reviewed, mainly including physically/chemically engineering LBNPs and directly modifying physiological barriers by auxiliary treatments. Then the potentials and challenges for successful translation of these preclinical studies into the clinic are discussed. In the end, a forward look at the strategies on manipulating protein corona (PC) is addressed, which may pull off the trick of overcoming those physiological barriers and significantly improve the efficacy and safety of LBNP-based NADs delivery.

Recent Therapeutic Gene Editing Applications to Genetic Disorders

Recent years have witnessed unprecedented progress in therapeutic gene editing, revolutionizing the approach to treating genetic disorders. In this comprehensive review, we discuss the progression of milestones leading to the emergence of the clustered regularly interspaced short palindromic repeats (CRISPR)-based technology as a powerful tool for precise and targeted modifications of the human genome. CRISPR-Cas9 nuclease, base editing, and prime editing have taken center stage, demonstrating remarkable precision and efficacy in targeted ex vivo and in vivo genomic modifications. Enhanced delivery systems, including viral vectors and nanoparticles, have further improved the efficiency and safety of therapeutic gene editing, advancing their clinical translatability. The exploration of CRISPR-Cas systems beyond the commonly used Cas9, such as the development of Cas12 and Cas13 variants, has expanded the repertoire of gene editing tools, enabling more intricate modifications and therapeutic interventions. Outstandingly, prime editing represents a significant leap forward, given its unparalleled versatility and minimization of off-target effects. These innovations have paved the way for therapeutic gene editing in a multitude of previously incurable genetic disorders, ranging from monogenic diseases to complex polygenic conditions. This review highlights the latest innovative studies in the field, emphasizing breakthrough technologies in preclinical and clinical trials, and their applications in the realm of precision medicine. However, challenges such as off-target effects and ethical considerations remain, necessitating continued research to refine safety profiles and ethical frameworks.

Base Editors-Mediated Gene Therapy in Hematopoietic Stem Cells for Hematologic Diseases

Base editors, developed from the CRISPR/Cas system, consist of components such as deaminase and Cas variants. Since their emergence in 2016, the precision, efficiency, and safety of base editors have been gradually optimized. The feasibility of using base editors in gene therapy has been demonstrated in several disease models. Compared with the CRISPR/Cas system, base editors have shown great potential in hematopoietic stem cells (HSCs) and HSC-based gene therapy, because they do not generate double-stranded breaks (DSBs) while achieving the precise realization of single-base substitutions. This precise editing mechanism allows for the permanent correction of genetic defects directly at their source within HSCs, thus promising a lasting therapeutic effect. Recent advances in base editors are expected to significantly increase the number of clinical trials for HSC-based gene therapies. In this review, we summarize the development and recent progress of DNA base editors, discuss their applications in HSC gene therapy, and highlight the prospects and challenges of future clinical stem cell therapies.

Interview with Drew Weissman, 2023 Nobel Laureate in Physiology or Medicine

Drew Weissman, MD, PhD, received the 2023 Nobel Prize in Physiology or Medicine together with Katalin Karikó, PhD. Dr. Weissman received his bachelor's and master's degrees from Brandeis University, Waltham, MA, in 1981. He received his MD and PhD in 1987 from Boston University, Boston, MA, and this was followed by a residency at Beth Israel Deaconess Medical Center, Boston, MA. He then completed a fellowship at the National Institute of Allergy and Infectious Diseases under the supervision of Anthony Fauci, MD. He joined the Faculty at the University of Pennsylvania, Philadelphia, in 1997, where, in collaboration with Dr. Katalin Karikó, he explored the use of messenger RNA (mRNA) to drive heterologous gene expression in human cells. They overcame the notorious susceptibility of RNAs to degradation by packaging the mRNA in lipid nanoparticles and learned to both optimize protein expression and attenuate the inflammatory response to the exogenous RNAs by [covalently] modifying bases in the RNA sequence. This work has revolutionized immunization technology and allowed for the production of the most effective vaccines to prevent COVID-19.

The difficult translational pathway from animal models to patients

Lee et al.1 analyzed the impacts of lentiviral vector transduction and CRISPR-Cas9/homology-directed repair editing on hematopoietic stem and progenitor cell (HSPC) engraftment and clonal dynamics. The study suggests that relative to lentiviral-vector-mediated gene addition, homology-directed repair editing is inefficient in vivo and might impair the engraftment and differentiation of HSPCs.

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.

mRNA-based therapeutics: looking beyond COVID-19 vaccines

Recent advances in mRNA technology and its delivery have enabled mRNA-based therapeutics to enter a new era in medicine. The rapid, potent, and transient nature of mRNA-encoded proteins, without the need to enter the nucleus or the risk of genomic integration, makes them desirable tools for treatment of a range of diseases, from infectious diseases to cancer and monogenic disorders. The rapid pace and ease of mass-scale manufacturability of mRNA-based therapeutics supported the global response to the COVID-19 pandemic. Nonetheless, challenges remain with regards to mRNA stability, duration of expression, delivery efficiency, and targetability, to broaden the applicability of mRNA therapeutics beyond COVID-19 vaccines. By learning from the rapidly expanding preclinical and clinical studies, we can optimise the mRNA platform to meet the clinical needs of each disease. Here, we will summarise the recent advances in mRNA technology; its use in vaccines, immunotherapeutics, protein replacement therapy, and genomic editing; and its delivery to desired specific cell types and organs for development of a new generation of targeted mRNA-based therapeutics.

Regulation of inflammatory diseases via the control of mRNA decay

Inflammation orchestrates a finely balanced process crucial for microorganism elimination and tissue injury protection. A multitude of immune and non-immune cells, alongside various proinflammatory cytokines and chemokines, collectively regulate this response. Central to this regulation is post-transcriptional control, governing gene expression at the mRNA level. RNA-binding proteins such as tristetraprolin, Roquin, and the Regnase family, along with RNA modifications, intricately dictate the mRNA decay of pivotal mediators and regulators in the inflammatory response. Dysregulated activity of these factors has been implicated in numerous human inflammatory diseases, underscoring the significance of post-transcriptional regulation. The increasing focus on targeting these mechanisms presents a promising therapeutic strategy for inflammatory and autoimmune diseases. This review offers an extensive overview of post-transcriptional regulation mechanisms during inflammatory responses, delving into recent advancements, their implications in human diseases, and the strides made in therapeutic exploitation.

The clinical impact of mRNA therapeutics in the treatment of cancers, infections, genetic disorders, and autoimmune diseases

mRNA-based therapeutics have revolutionized medicine and the pharmaceutical industry. The recent progress in the optimization and formulation of mRNAs has led to the development of a new therapeutic platform with a broad range of applications. With a growing body of evidence supporting the use of mRNA-based drugs for precision medicine and personalized treatments, including cancer immunotherapy, genetic disorders, and autoimmune diseases, this emerging technology offers a rapidly expanding category of therapeutic options. Furthermore, the development and deployment of mRNA vaccines have facilitated a prompt and flexible response to medical emergencies, exemplified by the COVID-19 outbreak. The establishment of stable and safe mRNA molecules carried by efficient delivery systems is now available through recent advances in molecular biology and nanotechnology. This review aims to elucidate the advancements in the clinical applications of mRNAs for addressing significant health-related challenges such as cancer, autoimmune diseases, genetic disorders, and infections and provide insights into the efficacy and safety of mRNA therapeutics in recent clinical trials.

"Treatment with curative intent": the emergence of genetic therapies for sickle cell anemia

ABSTRACT

The root cause of sickle cell anemia has been known for 7 decades, yet no curative therapies have been available other than allogeneic bone marrow transplantation, for which applicability is limited. Two potentially curative therapies based on gene therapy and gene editing strategies have recently received US Food and Drug Administration approval. This review surveys the nature of these therapies and the opportunities and issues raised by the prospect of definitive genetically based therapies being available in clinical practice.

Chimeric antigen receptor therapy meets mRNA technology

Genetically engineered immune cells expressing chimeric antigen receptors (CARs) have emerged as a new game changer in cancer immunotherapy. The utility of CAR T cell therapy against hematological malignancies has been validated in clinical practice. Other CAR immune cells are currently under investigation to improve the potency of CAR therapy in solid tumors. As a new class of therapeutic modalities, mRNA-based therapeutics hold enormous potential beyond COVID-19 mRNA vaccines. Arming immune cells with mRNA-encoded CARs represents a new frontier in cancer and beyond, enabling in vivo generation of CAR cells without causing transgene integration. In this review, we summarize recent advances in mRNA-based CAR immunotherapies and highlight their opportunities and challenges for the development of a new generation of living drugs.

Engineered virus-like particles for transient delivery of prime editor ribonucleoprotein complexes in vivo

Prime editing enables precise installation of genomic substitutions, insertions and deletions in living systems. Efficient in vitro and in vivo delivery of prime editing components, however, remains a challenge. Here we report prime editor engineered virus-like particles (PE-eVLPs) that deliver prime editor proteins, prime editing guide RNAs and nicking single guide RNAs as transient ribonucleoprotein complexes. We systematically engineered v3 and v3b PE-eVLPs with 65- to 170-fold higher editing efficiency in human cells compared to a PE-eVLP construct based on our previously reported base editor eVLP architecture. In two mouse models of genetic blindness, single injections of v3 PE-eVLPs resulted in therapeutically relevant levels of prime editing in the retina, protein expression restoration and partial visual function rescue. Optimized PE-eVLPs support transient in vivo delivery of prime editor ribonucleoproteins, enhancing the potential safety of prime editing by reducing off-target editing and obviating the possibility of oncogenic transgene integration.

Targeted, safe, and efficient gene delivery to human hematopoietic stem and progenitor cells in vivo using the engineered AVID adenovirus vector platform

Targeted delivery and cell-type-specific expression of gene-editing proteins in various cell types in vivo represent major challenges for all viral and non-viral delivery platforms developed to date. Here, we describe the development and analysis of artificial vectors for intravascular delivery (AVIDs), an engineered adenovirus-based gene delivery platform that allows for highly targeted, safe, and efficient gene delivery to human hematopoietic stem and progenitor cells (HSPCs) in vivo after intravenous vector administration. Due to a set of refined structural modifications, intravenous administration of AVIDs did not trigger cytokine storm, hepatotoxicity, or thrombocytopenia. Single intravenous administration of AVIDs to humanized mice, grafted with human CD34+ cells, led to up to 20% transduction of CD34+CD38-CD45RA- HSPC subsets in the bone marrow. Importantly, targeted in vivo transduction of CD34+CD38-CD45RA-CD90-CD49f+ subsets, highly enriched for human hematopoietic stem cells (HSCs), reached up to 19%, which represented a 1,900-fold selectivity in gene delivery to HSC-enriched over lineage-committed CD34-negative cell populations. Because the AVID platform allows for regulated, cell-type-specific expression of gene-editing technologies as well as expression of immunomodulatory proteins to ensure persistence of corrected HSCs in vivo, the HSC-targeted AVID platform may enable development of curative therapies through in vivo gene correction in human HSCs after a single intravenous administration.

Understanding genetic heterogeneity in gene-edited hematopoietic stem cell products

CRISPR/Cas gene editing has transformed genetic research and is poised to drive the next generation of gene therapies targeting hematopoietic stem cells (HSCs). However, the installation of the "desired" edit is most often only achieved in a minor subset of alleles. The array of cellular pathways triggered by gene editing tools produces a broad spectrum of "undesired" editing outcomes, including short insertions and deletions (indels) and chromosome rearrangements, leading to considerable genetic heterogeneity in gene-edited HSC populations. This heterogeneity may undermine the effect of the genetic intervention since only a subset of cells will carry the intended modification. Also, undesired mutations represent a potential safety concern as gene editing advances toward broader clinical use. Here, we will review the different sources of "undesired" edits and will discuss strategies for their mitigation and control.

Emerging mRNA therapies for cardiac fibrosis

Cardiac fibrosis remains an unmet clinical need that has so far proven difficult to eliminate using current therapies. As such, novel technologies are needed that can target the pathological fibroblasts responsible for fibrosis and adverse tissue remodeling. mRNA encapsulated in lipid nanoparticles (LNPs) is an emerging technology that could offer a solution to this problem. Indeed, this strategy has already shown clinical success with the mRNA COVID-19 vaccines. In this AJP perspective, we discuss how this technology can be leveraged to specifically target cardiac fibrosis via several complementary strategies. First, we discuss the successful preclinical studies in a mouse model of cardiac injury to use T cell-targeted LNPs to produce anti-fibroblast chimeric antigen receptor T (CAR T) cells in vivo that could effectively reduce cardiac fibrosis. Next, we discuss how these T cell-targeted LNPs could be used to generate T regulatory cells (T-regs), which could migrate to areas of active fibrosis and dampen inflammation through paracrine effects as an alternative to active fibroblast killing by CAR T cells. Finally, we conclude with thoughts on directly targeting pathological fibroblasts to deliver RNAs that could interfere with fibroblast activation and activity. We hope this discussion serves as a catalyst for finding approaches that harness the power of mRNA and LNPs to eliminate cardiac fibrosis and treat other fibrotic diseases amenable to such interventions.NEW & NOTEWORTHY Cardiac fibrosis has few specific interventions available for effective treatment. mRNA encapsulated in lipid nanoparticles could provide a novel solution for treating cardiac fibrosis. This AJP perspective discusses what possible strategies could rely on this technology, from in vivo-produced CAR T cells that kill pathological fibroblasts to in vivo-produced T regulatory cells that dampen the concomitant profibrotic inflammatory cells contributing to remodeling, directly targeting fibroblasts and eliminating them or silencing profibrotic pathways.

Transcriptional Repressor BCL11A in Erythroid Cells

BCL11A, a zinc finger repressor, is a stage-specific transcription factor that controls the switch from fetal (HbF, α2γ2) to adult (HbA, α2β2) hemoglobin in erythroid cells. While BCL11A was known as a factor critical for B-lymphoid cell development, its relationship to erythroid cells and HbF arose through genome-wide association studies (GWAS). Subsequent work validated its role as a silencer of γ-globin gene expression in cultured cells and mice. Erythroid-specific loss of BCL11A rescues the phenotype of engineered sickle cell disease (SCD) mice, thereby suggesting that downregulation of BCL11A expression might be beneficial in patients with SCD and β-thalassemia. Common genetic variation in GWAS resides in an erythroid-specific enhancer within the BCL11A gene that is required for its own expression. CRISPR/Cas9 gene editing of the enhancer revealed a GATA-binding site that confers a large portion of its regulatory function. Disruption of the GATA site leads to robust HbF reactivation. Advancement of a guide RNA targeting the GATA-binding site in clinical trials has recently led to approval of first-in-man use of ex vivo CRISPR editing of hematopoietic stem/progenitor cells (HSPCs) as therapy of SCD and β-thalassemia. Future challenges include expanding access and infrastructure for delivery of genetic therapy to eligible patients, reducing potential toxicity and costs, exploring prospects for in vivo targeting of hematopoietic stem cells (HSCs), and developing small molecule drugs that impair function of BCL11A protein as an alternative option.

Unleashing the Potential: Designing Antibody-Targeted Lipid Nanoparticles for Industrial Applications with CMC Considerations and Clinical Outlook

Antibody-targeted lipid nanoparticles (Ab-LNPs) are rapidly gaining traction as multifaceted platforms in precision medicine, adept at delivering a diverse array of therapeutic agents, including nucleic acids and small molecules. This review provides an incisive overview of the latest developments in the field of Ab-LNP technology, with a special emphasis on pivotal design aspects such as antibody engineering, bioconjugation strategies, and advanced formulation techniques. Furthermore, it addresses critical chemistry, manufacturing, and controls (CMC) considerations and thoroughly examines the in vivo dynamics of Ab-LNPs, underscoring their promising potential for clinical application. By seamlessly blending scientific advancements with practical industrial perspectives, this review casts a spotlight on the burgeoning role of Ab-LNPs as an innovative and potent tool in the realm of targeted drug delivery.

Gene addition for beta thalassemia

Individuals with transfusion-dependent beta thalassemia require a high burden of care and experience significant morbidity from the underlying disease and its treatment, which negatively impact the quality of life. Allogeneic hematopoietic stem cell transplantation offers the chance for a cure, but donor availability and transplant-related risks, especially in older patients, limit its use. Gene addition utilizing autologous CD34+ cells is an alternative, potentially curative, treatment option. Several clinical trials have investigated the use of lentiviral vectors containing a functional beta globin gene, including Lentiglobin BB305, GLOBE, and TNS9.3.55. The efficacy and safety data from these ongoing trials are discussed in this review.

Nano-bio interactions in mRNA nanomedicine: Challenges and opportunities for targeted mRNA delivery

Upon entering the biological milieu, nanomedicines swiftly interact with the surrounding tissue fluid, subsequently being enveloped by a dynamic interplay of biomacromolecules, such as carbohydrates, nucleic acids, and cellular metabolites, but with predominant serum proteins within the biological corona. A notable consequence of the protein corona phenomenon is the unintentional loss of targeting ligands initially designed to direct nanomedicines toward particular cells or organs within the in vivo environment. mRNA nanomedicine displays high demand for specific cell and tissue-targeted delivery to effectively transport mRNA molecules into target cells, where they can exert their therapeutic effects with utmost efficacy. In this review, focusing on the delivery systems and tissue-specific applications, we aim to update the nanomedicine population with the prevailing and still enigmatic paradigm of nano-bio interactions, a formidable hurdle in the pursuit of targeted mRNA delivery. We also elucidate the current impediments faced in mRNA therapeutics and, by contemplating prospective avenues-either to modulate the corona or to adopt an 'ally from adversary' approach-aim to chart a course for advancing mRNA nanomedicine.

From lipid nanoparticles to precision therapies for hematologic diseases: getting closer

Modification of hematopoietic stem cells, in both molecular and cellular terms, has been a long-pursued goal in experimental and clinical hematology. In a recent article published in Science, Breda et al describe a novel method for the genetic modification of hematopoietic stem cells. This new experimental approach, based on the use of lipid nanoparticles, represents an important step forward in the development of genetic and cellular therapies for hematologic diseases. A general overview of the article by Breda et al and some analysis, comments, and perspectives are presented in this editorial commentary.

Recruiting In Vitro Transcribed mRNA against Cancer Immunotherapy: A Contemporary Appraisal of the Current Landscape

Over 100 innovative in vitro transcribed (IVT)-mRNAs are presently undergoing clinical trials, with a projected substantial impact on the pharmaceutical market in the near future. Τhe idea behind this is that after the successful cellular internalization of IVT-mRNAs, they are subsequently translated into proteins with therapeutic or prophylactic relevance. Simultaneously, cancer immunotherapy employs diverse strategies to mobilize the immune system in the battle against cancer. Therefore, in this review, the fundamental principles of IVT-mRNA to its recruitment in cancer immunotherapy, are discussed and analyzed. More specifically, this review paper focuses on the development of mRNA vaccines, the exploitation of neoantigens, as well as Chimeric Antigen Receptor (CAR) T-Cells, showcasing their clinical applications and the ongoing trials for the development of next-generation immunotherapeutics. Furthermore, this study investigates the synergistic potential of combining the CAR immunotherapy and the IVT-mRNAs by introducing our research group novel, patented delivery method that utilizes the Protein Transduction Domain (PTD) technology to transduce the IVT-mRNAs encoding the CAR of interest into the Natural Killer (NK)-92 cells, highlighting the potential for enhancing the CAR NK cell potency, efficiency, and bioenergetics. While IVT-mRNA technology brings exciting progress to cancer immunotherapy, several challenges and limitations must be acknowledged, such as safety, toxicity, and delivery issues. This comprehensive exploration of IVT-mRNA technology, in line with its applications in cancer therapeutics, offers valuable insights into the opportunities and challenges in the evolving landscape of cancer immunotherapy, setting the stage for future advancements in the field.

Lung and liver editing by lipid nanoparticle delivery of a stable CRISPR-Cas9 RNP

Lipid nanoparticle (LNP) delivery of CRISPR ribonucleoproteins (RNPs) has the potential to enable high-efficiency in vivo genome editing with low toxicity and an easily manufactured technology, if RNP efficacy can be maintained during LNP production. In this study, we engineered a thermostable Cas9 from Geobacillus stearothermophilus (GeoCas9) using directed evolution to generate iGeoCas9 evolved variants capable of robust genome editing of cells and organs. iGeoCas9s were significantly better at editing cells than wild-type GeoCas9, with genome editing levels >100X greater than those induced by the native GeoCas9 enzyme. Furthermore, iGeoCas9 RNP:LNP complexes edited a variety of cell lines and induced homology-directed repair (HDR) in cells receiving co-delivered single-stranded DNA (ssDNA) templates. Using tissue-selective LNP formulations, we observed genome editing of 35‒56% efficiency in the liver or lungs of mice that received intravenous injections of iGeoCas9 RNP:LNPs. In particular, iGeoCas9 complexed to acid-degradable LNPs edited lung tissue in vivo with an average of 35% efficiency, a significant improvement over editing efficiencies observed previously using viral or non-viral delivery strategies. These results show that thermostable Cas9 RNP:LNP complexes are a powerful alternative to mRNA:LNP delivery vehicles, expanding the therapeutic potential of genome editing.

Recent advances in hematopoietic gene therapy for genetic disorders

Hematopoietic gene therapy is based on the transplantation of gene-modified autologous hematopoietic stem cells and since the inception of this approach, many technological and medical improvements have been achieved. This review focuses on the clinical studies that have used hematopoietic gene therapy to successfully treat several rare and severe genetic disorders of the blood or immune system as well as some non-hematological diseases. Today, in some cases hematopoietic gene therapy has progressed to the point of being equal to, or better than, allogeneic bone marrow transplant. In others, further improvements are needed to obtain more consistent efficacy or to reduce the risks posed by vectors or protocols. Several hematopoietic gene therapy products showing both long-term efficacy and safety have reached the market, but economic considerations challenge the possibility of patient access to novel disease-modifying therapies. © 2023 Published by Elsevier Masson SAS on behalf of French Society of Pediatrics.