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Found: 26 179
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Messenger RNA and guide RNA distributions in lipid nanoparticles impact gene-editing efficiency in vivo.
Lipid nanoparticles (LNPs) are among the most advanced non-viral vectors for CRISPR-based gene-editing therapeutics. Co-packaging of messenger RNA (mRNA) and guide RNA (gRNA) inherently produces heterogeneous payload distributions. The impact of this heterogeneity on editing performance remains unclear. Here, we utilize cylindrical illumination confocal spectroscopy (CICS) for single-particle interrogation of ALC-0315 and DLin-MC3-DMA LNPs prepared by three different mixing methods. CICS resolves four distinct subpopulations: co-encapsulated (50.7%-60.4%), gRNA only (30.0%-36.5%), mRNA only (2.0%-3.4%), and empty (4.2%-13.8%), and it uncovers broad, particle-to-particle variability in RNA copy number within each class. Structure-function analysis reveals that LNP formulation and mixing processes influence payload distribution, resulting in a negative correlation between the fraction of empty LNPs and RNA loading per particle. We further investigated the correlation between these quality attributes and therapeutic performance. In mice, ALC-0315 LNPs carrying higher cargo loads (9.8 vs. 8.0 mRNA copies and 25.4 vs. 20.3 gRNA copies per co-encapsulated particle) yielded 1.5-fold higher in vivo editing activity (55.4% vs. 36.3% insertions and deletions [indels]) despite nearly identical biophysical characteristics including LNP size and RNA encapsulation. These results establish payload distribution as a potential determinant of gene-editing potency and demonstrate single-particle CICS as a powerful tool for rational design of multi-component nucleic acid-delivery systems.
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Self-inactivating AAV-CRISPR at different ages enables sustained amelioration of Huntington's disease deficits in BAC226Q mice.
Huntington's disease (HD) is a monogenic autosomal dominant neurodegenerative disorder caused by a CAG repeat expansion in exon 1 of the HTT gene, yielding a gain-of-toxic-function mutant Huntingtin protein (mHTT). CRISPR-Cas9 is a potentially powerful therapeutic strategy for HD by eliminating mutant HTT (mHTT) gene. We developed a specific SaCas9 guide RNA to target human mHTT and a self-inactivating gene editing system that abolishes SaCas9 after a short transient expression for high gene editing efficiency and maximal safety to prevent off-target effects. Both conventional and the self-inactivating gene editing systems successfully eliminated mHTT gene, 60 to 90% mHTT protein and 90% of mHTT aggregation in BAC226Q mouse brains, which resulted in significant long-term rescue of neuropathology, motor deficits, weight loss, and shortened life span. These beneficial effects were observed when gene editing was applied before, at, and well after the onset of pathological and behavioral abnormalities. These proof-of-concept data demonstrate that gene editing can be a highly effective therapeutic approach for HD.
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An efficient transgene-free DNA-editing system for Arabidopsis using a fluorescent marker.
OBJECTIVE: To obtain transgene-free progeny by constructing a DNA editing system with a fluorescent screening marker gene and two pairs of single-guide RNAs to simultaneously recognize two different sites in the target gene encoding Arabidopsis microRNA(miR)160A RESULTS: The T1 seeds with red fluorescence were easily identified and were selected to verify that the proportion of miR160A knockout mutants reached approximately 50%. Seeds with no fluorescence in the T2 generation were selected and screened for homozygous mutants. In the T2 generation plants, the Cas9 fragment was not detected by polymerase chain reaction. The traits of the homozygous mutants were stably inherited by the T2 population. CONCLUSIONS: A highly efficient DNA-editing construct was successfully developed and can be used as a plant genome site-specific editing tool that may be useful for improving plant genetic resources.
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On RNA-programmable gene modulation as a versatile set of principles targeting muscular dystrophies.
The repurposing of RNA-programmable CRISPR systems from genome editing into epigenome editing tools is gaining pace, including in research and development efforts directed at tackling human disorders. This momentum stems from the increasing knowledge regarding the epigenetic factors and networks underlying cell physiology and disease etiology and from the growing realization that genome editing principles involving chromosomal breaks generated by programmable nucleases are prone to unpredictable genetic changes and outcomes. Hence, engineered CRISPR systems are serving as versatile DNA-targeting scaffolds for heterologous and synthetic effector domains that, via locally recruiting transcription factors and chromatin remodeling complexes, seek interfering with loss-of-function and gain-of-function processes underlying recessive and dominant disorders, respectively. Here, after providing an overview about epigenetic drugs and CRISPR-Cas-based activation and interference platforms, we cover the testing of these platforms in the context of molecular therapies for muscular dystrophies. Finally, we examine attributes, obstacles, and deployment opportunities for CRISPR-based epigenetic modulating technologies.
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CRISPR-Cas9: A History of Its Discovery and Ethical Considerations of Its Use in Genome Editing.
The development of a method for genome editing based on CRISPR-Cas9 technology was awarded The Nobel Prize in Chemistry in 2020, less than a decade after the discovery of all principal molecular components of the system. For the first time in history a Nobel prize was awarded to two women, Emmanuelle Charpentier and Jennifer Doudna, who made key discoveries in the field of DNA manipulation with the CRISPR-Cas9 system, so-called "genetic scissors". It is difficult to overestimate the importance of the technique as it enables one not only to manipulate genomes of model organisms in scientific experiments, and modify characteristics of important crops and animals, but also has the potential of introducing revolutionary changes in medicine, especially in treatment of genetic diseases. The original biological function of CRISPR-Cas9 system is the protection of prokaryotes from mobile genetic elements, in particular viruses. Currently, CRISPR-Cas9 and related technologies have been successfully used to cure life-threatening diseases, make coronavirus detection tests, and even to modify human embryo cells with the consequent birth of babies carrying the introduced modifications. This intervention with human germplasm cells resulted in wide disapproval in the scientific community due to ethical concerns, and calls for a moratorium on inheritable genomic manipulations. This review focuses on the history of the discovery of the CRISPR-Cas9 system with some aspects of its current applications, including ethical concerns about its use in humans.
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Viability-Based Assessment Reveals True Efficiency of CRISPR-Cas9 Transfection Methods in Rabbit Spermatozoa.
Modern genome editing tools such as CRISPR-Cas9 have revolutionized mammalian genome engineering, yet translation to in vivo applications remains limited by low efficiency and frequent occurrence of mosaicism. Sperm-mediated delivery of editing reagents is one proposed alternative that may mitigate these issues. This method depends on efficient transfection of genome editing materials into viable spermatozoa, a critical yet frequently overlooked parameter. Using FACS, we compared electroporation (Neon NxT) and lipofection (CRISPRMAX) for introducing CRISPR-Cas9 ribonucleoproteins into viable rabbit spermatozoa. Electroporation, shown to enable Cas9 and plasmid transfection in spermatozoa from other species, performed poorly once dead spermatozoa were excluded. In contrast, Lipofectamine CRISPRMAX improved transfection efficiency with minimal effects on spermatozoa viability and motility. These findings emphasize the importance of distinguishing true transfection (transfection of viable spermatozoa) from total transfection and highlight lipofection as a promising alternative to electroporation for sperm-based genome editing, with potential applications in rabbit genome engineering.
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Protocol for identification of sgRNA mutants using high-throughput screening technique and multiplex genome editing.
In the CRISPR-Cas9 system, tandem expression of multiple identical single-guide RNAs (sgRNAs) often triggers homologous sequences loss, which affects multiplex genome editing efficiencies. Here, we present a protocol for high-throughput screening of functional sgRNAs with nonrepetitive mutants. We describe steps for constructing the screening platform, designing and constructing sgRNA libraries, and screening sgRNA mutants. These mutants can interact with the Cas9 protein, enabling multiplex genome editing. For complete details on the use and execution of this protocol, please refer to Liang et al.1.
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Reporter gene imaging "visualized" the integration of two growing technologies: CRISPR/Cas9-based genome editing and induced pluripotent stem cell therapy.
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CRISPR-Based Precision Molecular Diagnostics for Disease Detection and Surveillance.
Sensitive, rapid, and portable molecular diagnostics is the future of disease surveillance, containment, and therapy. The recent SARS-CoV-2 pandemic has reminded us of the vulnerability of lives from ever-evolving pathogens. At the same time, it has provided opportunities to bridge the gap by translating basic molecular biology into therapeutic tools. One such molecular biology technique is CRISPR (clustered regularly interspaced short palindromic repeat) which has revolutionized the field of molecular diagnostics at the need of the hour. The use of CRISPR-Cas systems has been widespread in biology research due to the ease of performing genetic manipulations. In 2012, CRISPR-Cas systems were, for the first time, shown to be reprogrammable, i.e., capable of performing sequence-specific gene editing. This discovery catapulted the field of CRISPR-Cas research and opened many unexplored avenues in the field of gene editing, from basic research to therapeutics. One such field that benefitted greatly from this discovery was molecular diagnostics, as using CRISPR-Cas technologies enabled existing diagnostic methods to become more sensitive, accurate, and portable, a necessity in disease control. This Review aims to capture some of the trajectories and advances made in this arena and provides a comprehensive understanding of the methods and their potential use as point-of-care diagnostics.
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Efficient and Economical Targeted Insertion in Plant Genomes via Protoplast Regeneration.
Versatile genome editing can be facilitated by the insertion of DNA sequences into specific locations. Current protocols involving CRISPR and Cas proteins rely on low efficiency homology-directed repair or non-homologous end joining with modified double-stranded DNA oligonucleotides as donors. Our simple protocol eliminates the need for expensive equipment, chemical and enzymatic donor DNA modification, or plasmid construction by using polyethylene glycol-calcium to deliver non-modified single-stranded DNA oligonucleotides and CRISPR-Cas9 ribonucleoprotein into protoplasts. Plants regenerated via edited protoplasts achieved targeted insertion frequencies of up to 50% in Nicotiana benthamiana and 13.6% in rapid cycling Brassica oleracea without antibiotic selection. Using a 60 nt donor containing 27 nt in each homologous arm, 6/22 regenerated N. benthamiana plants showed targeted insertions, and one contained a precise insertion of a 6 bp HindIII site. The inserted sequences were transmitted to the next generation and invite the possibility of future exploration of versatile genome editing by targeted DNA insertion in plants.
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