CRISPR-Cas method

Overview

The CRISPR-Cas method is a genome editing technology derived from a prokaryotic adaptive immune system and repurposed as a programmable laboratory and therapeutic tool. Its core components are a guide RNA and a CRISPR-associated nuclease, most commonly Cas9, though alternative effectors such as Cas12a are also used. The guide RNA base-pairs with a complementary genomic sequence located next to a protospacer adjacent motif (PAM), positioning the nuclease to introduce a site-specific double-strand break. Cells repair that break either by error-prone non-homologous end joining, which typically disrupts the targeted gene, or by homology-directed repair, which can incorporate a supplied template such as a single-stranded oligodeoxynucleotide to correct a mutation or insert new sequence. Catalytically modified derivatives extend the platform beyond cutting: base editing and prime editing install defined sequence changes without a double-strand break, and CRISPR interference (CRISPRi) uses a nuclease-dead Cas protein to repress transcription. Cas9 has also been adapted for purposes other than editing, notably targeted enrichment of specific genomic regions ahead of long-read nanopore sequencing, which enables deep analysis of variable or repetitive loci in native, unamplified DNA.

Because targeting is specified entirely by the guide RNA sequence, CRISPR-Cas can be redirected to essentially any locus in any organism, making it a foundational tool for functional genomics, disease modeling, and gene therapy. In practice, its clinical utility is limited less by the nuclease than by delivery: the editing machinery must reach the intended cells as messenger RNA, protein, or ribonucleoprotein, and strategies under investigation include lipid nanoparticle, polymeric carriers, engineered bacteria or yeast that secrete Cas9-loaded extracellular vesicles, and ex vivo electroporation of cells that are subsequently transplanted. Ex vivo approaches are furthest advanced in hematopoietic stem and progenitor cells, evaluated in humanized mouse models, and in hepatocyte transplantation for inherited metabolic liver disease. Therapeutic interest spans monogenic disorders such as beta-thalassemia, hemophilia, and Duchenne muscular dystrophy; oncology applications including melanoma and colorectal cancer, where editing is combined with Targeted Cancer Therapy strategies; and complex neurodegenerative disease, where CRISPR-Cas is being explored against Alzheimer's disease risk genes and pathways involving apolipoprotein E4, TREM2, amyloid beta, and microtubule-associated protein tau, with the blood–brain barrier posing an added delivery obstacle. Persistent technical concerns across all applications include off-target editing, immune responses to bacterial Cas proteins, and the efficiency and tissue specificity of delivery.

Recent Publications Summary

Recent publications highlight CRISPR-Cas method as a versatile platform for both therapeutic gene editing and high-resolution genomic analysis. In cancer models, CRISPR/Cas9 was paired with multiple delivery systems, including highly branched poly(β-amino ester) for Cas9 mRNA and sgRNA delivery to melanoma cells, where gene knockout reached up to 25.5% and transdermal application was demonstrated in vivo 42171238May. Other studies used engineered bacteria and yeast to orally deliver CRISPR/Cas9 components for colon cancer therapy, with extracellular vesicles carrying Cas9 protein and ART1-targeting sgRNA and producing significant tumor suppression in murine models 42044361Apr. Additional nanoplatforms combined CRISPR/Cas9 with lipid nanoparticle, biomimetic membranes, photothermal polymers, or high-entropy alloys to enable pancreas-selective editing, optogenetic CD274 editing in head and neck squamous cell carcinoma, thermogenetic CDK7 targeting in triple-negative breast cancer, and radioimmunotherapy sensitization in lung metastases 41741655Feb41624538Feb41774834Mar41914367Mar. A mesoporous silica nanosystem was also used to deliver CRISPR-Cas9 plasmids against C-C motif chemokine ligand 2 in breast cancer cells, reducing proliferation, migration, and invasion 41443126Dec.

Several studies focused on CRISPR-Cas method for in vivo correction or suppression of disease-causing genes in nonmalignant settings. In Duchenne muscular dystrophy, CRISPR-Cas9 disruption of a Let-7c binding site increased utrophin expression and improved muscle function in tissue-engineered human muscle and mdx mice 41877484Mar. In Huntington’s disease, a self-inactivating AAV-CRISPR system targeting mutant HTT produced substantial reductions in mutant protein and aggregation, with long-term rescue of neuropathology and motor deficits across multiple treatment time points 41849610Mar. In neonatal hepatocytes, electroporation-mediated CRISPR-Cas9 knockout did not significantly impair engraftment in vivo, supporting ex vivo gene-edited hepatocyte therapy for pediatric liver disease 41928587Apr. CRISPR/Cas9-mediated gene correction was also reported in human hematopoietic stem and progenitor cells, where correction rates were comparable in NSG and NBSGW mouse models 41987334Apr.

Beyond therapy, CRISPR-Cas method was used to interrogate genome structure, repair, and cell biology. Cas9-targeted nanopore sequencing was improved through nanopore adapter-enriched Cas9-targeted sequencing, enabling ultra-deep, selective long-read analysis of native DNA and revealing tandem amplifications in Staphylococcus aureus at single-cell resolution 42019502Apr. Another study found that endogenous RNA/DNA hybrids influenced CRISPR-Cas9 homology-directed repair, with reduced HDR at R-loop-enriched sites in proliferating hepatocyte-derived cells and increased HDR after RNaseH1 overexpression or G1 arrest 41909468Mar. MitoPerturb-Seq used CRISPR-Cas9-based single-cell screening to identify nuclear genes and pathways controlling mitochondrial DNA copy number and heteroplasmy, including responses to Tfam, Opa1, and Polg knockout 41922875Apr. Library-design work also addressed the balance between on-target activity and off-target risk, producing genome-wide knockout libraries for human and mouse screens 41887225Mar. In addition, CRISPR/Cas9 gene editing was applied to generate targeted mutations in Anolis lizard oocytes, expanding the experimental reach of the method in nontraditional model organisms 40744727Jul.

Review articles in this set emphasize the broad therapeutic promise of CRISPR-Cas method across neurodegeneration, autoimmune disease, hemophilia, malaria, mycotoxin control, and plant biotechnology. These reviews discuss CRISPR/Cas9 and next-generation editing strategies for Alzheimer’s disease, including targeting APOE4, APP, PSEN1, PSEN2, MAPT, and TREM2, as well as the integration of gene editing with stem cell therapy and biomimetic nanoparticles 41931258Apr41926312Apr41926312Apr. Other overviews describe CRISPR/Cas9’s role in hemophilia gene therapy, antimalarial drug-resistance research, sustainable mycotoxin management, and plant molecular farming 41863244Mar41472363Dec41654278Feb41870756Mar.

What Changes, What Holds

1. CRISPR-Cas is expanding as a delivery-sensitive cancer platform rather than a single editing modality
REINFORCES Cancer applications here mostly extend the baseline’s therapeutic framing: the new work shows that editing can be packaged in many additional carriers and even delivered transdermally or orally, but it does not alter the core account that CRISPR-Cas is a programmable genome-editing tool whose practical limits are dominated by delivery. The main takeaway is breadth of formulation, not a new mechanism of action 42171238May42044361Apr.

2. In vivo editing can now be used to restore function in nonmalignant disease models, but durability and translation remain the key questions
REINFORCES These studies strengthen the baseline’s claim that CRISPR-Cas is relevant to monogenic disease and ex vivo or in vivo therapeutic correction, especially for muscle, liver, and hematopoietic targets. They do not displace the established repair logic; instead, they add evidence that gene disruption or correction can produce phenotypic rescue in more mature disease models. What remains unsettled is how broadly these effects will hold in patients and over time 41877484Mar41849610Mar.

3. CRISPR-Cas is becoming a sharper tool for genome biology, not just editing, by improving how edited loci are read and interpreted
METHOD The new work mainly changes how the platform is studied and what can be measured with it: targeted nanopore sequencing becomes more selective, and CRISPR-based screens are used to map DNA repair and mitochondrial genetics at single-cell resolution. This extends the baseline’s note that Cas9 can be repurposed for targeted enrichment, but the central advance is methodological rather than a new biological role 42019502Apr41922875Apr.

4. The therapeutic scope of CRISPR-Cas is broadening into additional disease areas, but these reviews do not add new established uses
REINFORCES Review articles here reinforce the baseline’s view of CRISPR-Cas as a platform with wide translational reach, including neurodegeneration, hemophilia, malaria, and plant biotechnology. They do not overturn any settled mechanism or clinical limitation; instead, they consolidate emerging indications and emphasize combination strategies such as stem cells and nanoparticles. Because these are reviews, they mainly sharpen the map of where the field is heading rather than establish new facts 41931258Apr41863244Mar.

Overview update candidates: none.