New CRISPR variant cuts with 'superfidelity' — plus, light-controlled CRISPR switches

Key Findings

💡 Light-controlled CRISPR switches work across multiple gene editors

• Scientists created CASANOVA-A5, a blue light-activated switch that can turn CRISPR editing on and off in living cells by inserting a light sensor into an anti-CRISPR protein

• Unlike previous optogenetic tools that only worked with one type of Cas9, this system controls SpCas9, SaCas9, NmeCas9, and St1Cas9—giving researchers much broader flexibility

• The light switch provides precise spatial and temporal control over gene editing, potentially improving both safety and precision of CRISPR therapies

🩺 First approved CRISPR therapy expands to broader targets

• Following FDA approval of the first CRISPR therapy in late 2023 for sickle-cell anemia and β-thalassemia, clinical trials now target a much wider range of diseases including cancer and infectious diseases

• As of Monday, January 5th, dozens of CRISPR-Cas9 clinical trials are registered at clinicaltrials.gov, representing a rapid expansion beyond blood disorders

• The review highlights how CRISPR-based therapeutics are moving from proof-of-concept to treating diverse medical conditions

🔬 Compact CRISPR variant works in living mice

• Researchers identified Cj4Cas9, a smaller gene editor (985 amino acids) that successfully disrupted genes in mouse embryos and reduced cholesterol levels when delivered to mouse liver via AAV8

• An enhanced version called enCj4Cas9 shows two-fold higher activity and recognizes a simpler PAM sequence (N3GG), dramatically expanding the number of targetable sites in the genome

• The compact size makes it easier to package into delivery vehicles like viruses, potentially solving a major hurdle for getting CRISPR into patients

🧬 Prime editing tackles cholesterol gene variants at massive scale

• Scientists used prime editing to test 5,184 variants in the LDLR gene (linked to familial hypercholesterolemia) and found a continuous spectrum of effects on LDL-cholesterol uptake

• The activity-normalized screening approach successfully separated pathogenic from benign variants and showed strong correlation with LDL-C levels measured in UK Biobank participants

• Most currently unclassified rare LDLR variants met evidence thresholds for reclassification when the functional data was integrated with clinical guidelines

🦠 CRISPR tackles malaria drug resistance in Africa

• A systematic review found significantly low adoption of CRISPR technology for malaria research across Africa, despite the continent bearing the highest malaria burden

• CRISPR-Cas9 is being used to study how Plasmodium falciparum develops resistance to frontline antimalarial drugs, potentially accelerating new treatment discovery

• The technology could enhance diagnostic strategies and validate molecular markers for drug resistance, but technological and regulatory barriers limit current application

🐷 Gene-edited pigs inch closer to human transplants

• Multi-gene-edited pigs now lack three major xenoantigens (α-Gal, Neu5Gc, Sda) that trigger immune rejection and co-express human immune regulators to improve organ survival

• Advanced glycomics and AI-driven prediction are accelerating the discovery of additional immunogenic sugar molecules that need to be eliminated from donor pigs

• The convergence of glycobiology, genome engineering, and multi-omics is creating a roadmap for developing rejection-free organs to address global shortages