CMN Weekly (15 September 2023) - Your Weekly CRISPR Medicine News

Top picks

• Austrian researchers have developed a single-cell brain organoid CRISPR screen that can reveal developmental defects in autism. The CRISPR–human organoids–single-cell RNA sequencing (CHOOSE) system uses verified pairs of guide RNAs, inducible CRISPR–Cas9-based genetic disruption and single-cell transcriptomics for pooled loss-of-function screening in mosaic organoids. The study finds that perturbation of 36 high-risk autism spectrum disorder genes related to transcriptional regulation uncovers their effects on cell fate determination.
• German researchers have developed a genome-wide in vivo CRISPR screen to identify essential regulators of T cell migration to the CNS in a multiple sclerosis (MS) model. The study identified five essential brakes and 18 essential facilitators of T cell migration to the CNS and revealed critical regulators of the fundamental step in the induction of MS lesions.

Research

• A study by French researchers indicates that mitochondrial import of CRISPR-Cas12a system guide RNAs (crRNAs) may depend on their secondary structure/sequence. The researchers presume that imported crRNA allow reconstituting the active crRNA/Cas12a system in human mitochondria, which can contribute to developing effective strategies for mitochondrial gene editing and potential future treatment of mitochondrial diseases.
• Scientists in Poland have developed synthetic circuits based on split Cas9 to detect cellular events. The method is based on complementing halves of split Cas9 under different promoters and using self-assembling inteins that facilitate the reconstitution of the Cas9 halves.
• American researchers have used conjugative plasmids to deliver CRISPR-Cas9 systems specifically targeting pathogenic E. coli and Salmonella enterica and generate sequence-specific lethal double-stranded DNA breaks. The technology was effective both in vitro and in a murine neonate infection model, killing targeted bacterial strains without disrupting the normal gut microbiota.
• A new study has used CRISPR-Cas to knock down signalling protein Wnt10b expression in mice's brown adipose tissue (BAT). The approach decreased fat mass, smaller adipocytes, and elevated thermogenic gene expression, specifically UCP1.
• Researchers in the US have an approach for highly effective knock-in in mouse and rat models that achieves efficiencies over 90%. The strategy combines four methods: 1) AAV-mediated DNA delivery, 2) single-stranded DNA donor templates, 3) 2-cell embryo modification, and 4) CRISPR-Cas ribonucleoprotein (RNP) electroporation.
• Researchers in the US have combined sequence-specific RNA cleavage by CRISPR ribonucleases with programmable RNA repair to make precise deletions and insertions in RNA. The work establishes a recombinant RNA technology with immediate applications for the facile engineering of RNA viruses with potential applications for antiviral therapeutics, vaccines, and screening of mutations.
• American researchers present an alternative to CRISPRi for gene suppression that uses active Cas9 complexed with truncated gRNAs (tgRNAs). When targeted near transcriptional start sites, these short 14–15 nts tgRNAs efficiently repress the expression of several target genes throughout somatic tissues in Drosophila melanogaster without generating any detectable target site mutations.
• A recent study explored Focused Ultrasound Blood-Brain Barrier Opening (FUS-BBBO) for delivering adeno-associated viral vectors (AAVs) to treat genetic brain disorders. They found that targeting up to 105 brain sites increased gene delivery efficiency, safely transducing up to 60% of brain cells. However, when used for gene editing with CRISPR/Cas9, some neuron loss occurred, showing promise for large-scale gene therapy but with potential challenges.

Industry

• ERS Genomics and Demeetra have entered into a non-exclusive CRISPR-Cas9 licensing agreement. The agreement grants Demeetra access to the ERS CRISPR-Cas9 patent portfolio, which is sublicensable when combined with Cas-CLOVER.
• Precision BioSciences has hosted a virtual R&D day highlighting its proprietary ARCUS technology and recent in vivo gene editing program developments. The company's lead program, PBGENE-HBV, targets hepatitis B virus (HBV) and is approaching a 2024 clinical trial application (CTA) and investigational new drug (IND) application.
• Vertex Pharmaceuticals announces that three of its researchers have been awarded the 2024 Breakthrough Prize in Life Sciences "for developing life-transforming drug combinations that repair the defective chloride channel protein in patients with cystic fibrosis".
• CRISPR Therapeutics has announced that the company's President and Chairman of the Board, Rodger Novak, has decided to leave CRISPR Therapeutics. His position will be replaced by CEO Samarth Kulkarni, who will continue serving as CEO.

Detection

• Chinese researchers propose a multiplex diagnostic platform for the rapid, ultrasensitive, visual, and simultaneous detection of the SARS‑CoV‑2 open reading frame 1ab (ORF1ab) and N genes. The method uses CRISPR-Cas12a/Cas13a dual-enzyme digestion integrated with multiplex reverse transcriptase-recombinase polymerase amplification (RT-RPA).

Reviews

• Genome editing in engineered T cells for cancer immunotherapy. This review looks at innovative approaches that can widen the safe and effective use of adoptive cellular therapy to larger numbers of patients affected by cancer.
• Design of synthetic bacterial biosensors. The review describes how recent developments have paved the way for improved methods. These include toolkits for probing new host chassis, rational tuning of genetic components, directed evolution techniques, and advancements in bioinformatics.
• Prospects and challenges of CRISPR/Cas9 gene-editing technology in cancer research. This review summarises the mechanism and development of CRISPR-Cas9 gene-editing technology in recent years. It describes its potential application in cancer-related research, such as establishing human tumour disease models, gene therapy and immunotherapy.

Conferences and meetings

• You can register as an early bird until September 22 for the 4th Annual CRISPR 2.0 Congress in Boston on November 28-30. The conference focuses on 1) Next-generation developments and therapeutic applications of CRISPR technologies, 2) Innovative in vivo and ex vivo CRISPR delivery approaches, and 3) Overcoming key translational limitations facing drug developers seeking to enter the clinic.

Commentaries

• An article in Technology Networks outlines the potential for groundbreaking discoveries with CRISPR screening. The paper considers various platforms to modulate gene expression, experimental design, current challenges and the potential of CRISPR-Cas systems to understand and treat diseases, from cancers and congenital disorders to overcoming the growing prevalence of antimicrobial resistance.

Huh, heh, wow

• French researchers propose using Wikipedia to study the accumulation and transfer of scientific knowledge. They analyzed Wikipedia articles on CRISPR gene editing, demonstrating how they document the evolution of scientific discoveries into societal revolutions. The method leverages Wikipedia as a free and digital archive to track knowledge growth and its translation into public discourse, complementing traditional research methods.

News from CRISPR Medicine News

• Monday saw an interview with gastroenterologist Daniel Worthley from Queensland, Australia, who has engineered bacteria that detect specific extracellular DNA sequences and mutations from colorectal cancer cells, organoids, and tumours. The research demonstrates the feasibility of engineering harmless bacteria to detect cancer mutations, representing an important step toward non-invasive early cancer detection.