A novel genome-wide CRISPR screening strategy that will facilitate the systematic engineering of novel nonviral genome editing delivery methods, where the identified novel gene hits can be further used to increase editing efficiency for other therapeutically relevant cell types.
To systematically map cellular factors constraining nonviral genome editing, influencing uptake and intracellular trafficking, we develop a genome-wide CRISPR screening platform linking perturbation of 19,114 genes to editing outcomes in human cells. We identify six negative regulators of delivery whose depletion increases editing efficiency by up to six-fold across diverse payloads, loci, and cell types. We test the top two factors, GJB2 and BET1L, in two distinct human models: correction of a pathogenic adenine base mutation in KCNJ13 and introduction of a cytosine base mutation in the GABAA receptor gene. Depletion of either improves base-editing outcomes by 6-fold, potentially through effects on delivery. In a patient-derived model of retinal channelopathy, knockdown of either gene improves lipid nanoparticle base editing efficiency by over 3.5-fold. This enables functional restoration of Kir7.1 ion channels in a subset of edited cells, highlighting cellular barriers as actionable targets to enhance the potency of genetic therapies. Low editing efficiency of nonviral delivery in post mitotic tissues presents a challenge to the field of gene therapy. Here, authors dissect the genetic regulators of nonviral delivery in post mitotic retinal epithelial cells describe strategies for improved base editor delivery and editing.
Shivani Saxena, Meha Kabra, Amr A. Abdeen et al.· Nature Communications· 0 citations
A comprehensive review of delivery modalities of CRISPR systems solely in vivo that underpin their therapeutic translation and outlines the remaining barriers to durable, tissue-selective, and broadly deployable CRISPR therapeutics is provided.
L. Martin, Jure Bohinc, Alessandra Recchia et al.· International Journal on Bio...· 0 citations
Cells in multicellular eukaryotic systems are diverse biological units, with characteristics and functions determined by their molecular profiles. CRISPR–Cas9 genome editing has been widely used across biology to modulate gene expression and study gene function. However, there is currently no versatile and scalable method for editing a cell’s genome in response to endogenous cellular signals. Here, we report the engineering of a CRISPR guide RNA that efficiently confers genome editing in response to the catalytic activity of a target microRNA (miRNA) within a cell. miRNAs are short non-coding RNAs that are widely conserved across eukaryotes and can cleave their target RNA through almost perfect base pairing. In mammals, miRNAs are largely involved in development and homeostasis as well as disease progression and developmental disorders. To leverage these properties for genome editing, we developed a cuffed guide RNA (cgRNA) which is composed of a permutated order of sequence domains from the commonly used single guide RNA (sgRNA). These permutated domains were then concatenated with a miRNA target sequence, yielding a warped guide RNA that is inactive until cleaved by a complementary miRNA. We demonstrated that cgRNA enabled efficient miRNA activity-dependent genome editing in human and mouse cell lines. Biochemical and structural analyses revealed three stages of inhibition of the CRISPR genome-editing pathway for unprocessed cgRNA. Utilizing a lentiviral library of cgRNAs containing miRNA targets covering mouse genome-wide miRNAs, we identified miRNA cleavage activities and their sequence specificities in mouse embryonic stem cells and during smooth muscle cell differentiation. Furthermore, we showed that endogenous mRNA expression could be irreversibly recorded into a DNA sequence using a cgRNA targeted by a synthetic miRNA repeat. cgRNA is a simple, robust, miRNA activity-gated genome editing system that could facilitate the development of cell state-specific genome editing, the mapping of miRNA activity and gene expression landscapes, and the recording of molecularly determined cell states during the long-term progression of multicellular systems.
Arman Adel, Yuta Shuto, Shunsuke Kawasaki et al.· bioRxiv· 0 citations
CRISPR editors including nucleases, base editors, and prime editors can efficiently correct disease-causing genetic variants or disrupt target genes. Editing outcomes are commonly evaluated in cultured primary cells, patient-derived cells, or engineered cell lines to study the impact of genetic variation or as a first step before initiating animal studies or clinical translation. Delivery of editors as mRNA together with synthetic guide RNAs into mammalian cells can improve editing efficiency relative to plasmid-based approaches and prevent issues such as DNA integration or off-target editing from sustained expression. This article presents a workflow to prepare genome editor mRNA by in vitro transcription (IVT), including co-transcriptional capping and chemically-modified nucleotides, electroporate editor mRNA and guide RNAs into primary human fibroblasts, induced pluripotent stem cells (iPSCs), or lymphoblastoid cell lines (LCLs), and quantify editing outcomes by targeted amplicon sequencing on an Illumina platform followed by analysis using CRISPResso2. This workflow enables quantitative benchmarking of guide RNAs, electroporation parameters, and editor variants, and supports downstream applications including single-cell cloning, phenotypic assays, preclinical animal studies, and therapeutic development.
Maria Viskadourou, J. Workman, Emma V Burke et al.· Journal of Visualized Experi...· 0 citations
The types, principles and characteristics of gene editing systems are introduced in order to understand their requirements for delivery tools and to provide new insights to facilitate appropriate delivery systems or improve the efficacy of existing systems.
Fanyu Xue, Zixuan Xin, Gaojie Wang et al.· Artificial Cells Nanomedicin...· 0 citations
Genomic manipulation has advanced from stochastic nuclease‐mediated disruption toward programmable, deterministic precision. Early clustered regularly interspaced short palindromic repeats (CRISPR) strategies enabled targeted mutagenesis through double‐strand breaks; however, their therapeutic application is limited by genotoxicity, chromosomal instability, and dependence on endogenous repair pathways that are difficult to predict. In this review, we examined the transition from gene editing to genome writing, an approach that decouples genomic modification from host repair pathways to better balance efficiency, precision, and payload delivery. We also discussed the principles of precision technologies, including base and prime editors, and described emerging large‐scale writers, such as CRISPR‐associated transposases and recombinase‐based bridge RNAs, which enable the integration of multi‐kilobase synthetic modules. Beyond enzymatic mechanisms, we further considered the combined use of generative artificial intelligence, structural biology, and novel delivery architectures as potential strategies to overcome current biological limitations. Taken together, these developments point toward Generative Biology, in which computational design and high‐throughput screening transform the genome from a static substrate into a more dynamic model for complex, synthetic functional design.