CMN Weekly (12 January 2024) - Your Weekly CRISPR Medicine News

Top picks

• CRISPR-Cas9 editing of the rs10071329 genetic variant in human brown adipocytes offers insights for precision medicine in obesity, highlighting PPARGC1B's genetic variants as potential therapeutic targets. Swedish researchers changed rs10071329 from A/A to G/G, thereby increasing PPARGC1B levels, leading to higher triglyceride accumulation and enhanced mitochondrial gene expression without affecting adipogenic markers. The G/G genotype also improved mitochondrial respiration and lipolysis response to norepinephrine.
• Chinese researchers have demonstrated prime editing using CRISPR-Cas12a and circular RNAs in human cells. The team developed four circular RNA-mediated prime editor (CPE) systems that target T-rich areas and enable potential multiplex editing, with efficiencies up to 40.75% in human cells.

Research

• Prime editing efficiency has been increased up to 170-fold by developing new virus-like particles containing all the needed components - prime editor proteins, prime editing guide RNAs, and nicking single guide RNAs - and facilitating cargo release and localisation. In two genetic blindness mouse models, a single injection of v3 PE-eVLPs resulted in significant prime editing, protein expression restoration, and partial visual function recovery.
• Researchers in Japan have developed a new strategy for rapid mouse artificial chromosome cloning, contributing to the functional genomic analyses of human chromosomes. The method involves direct chromosome transfer from human iPSC and CRISPR-Cas9-mediated translocation.
• American researchers have used CRISPR-Cas9 to generate allogeneic donor T cells that protect from lethal acute graft-versus-host disease (GVHD) while maintaining robust anti-leukemic response. The method involves deletion of MIR155HG in primary human donor T cells, and its efficacy was demonstrated in a xenogeneic mouse model of acute GVHD.
• In a study exploring CRISPR-Cas9 alternatives for treating primary hyperoxaluria type 1 (PH1), AAV-delivered S. aureus nickases (D10ASaCas9) demonstrated promising results. This method effectively disrupted the Hao1 gene, reducing glycolate oxidase expression and showing therapeutic effects in PH1 mice. Crucially, it reduced off-target modifications and AAV integration, common concerns with CRISPR-Cas9.
• Russian scientists have successfully modified the Cas9 protein to achieve a 1.8-fold increase in the level of editing of the CXCR4 locus, a target for gene therapy of HIV infection. Cas9 was modified by introducing additional NLS signals, and ribonucleoprotein complexes of Cas9 and guide RNA were stabilised with poly-L-glutamic acid.
• CRISPR–Cas9–mediated knockout of cystathionine-γ-lyase in acute myeloid leukaemia (AML) cells shows that they rely on external cysteine for survival. Cysteine depletion in AML cells increases reactive oxygen species, leading to cell death due to glutathione deficiency. The study suggests targeting AML's antioxidant systems, like glutathione peroxidase 4, could enhance treatment efficacy, proposing combinations with ROS inducers or chemotherapy for potential therapeutic strategies.
• Scientists in China have used CRISPR-Cas9 to show that inhibiting the mitochondrial calcium uniporter (Mcu) reduces fat accumulation and improves metabolic health in mice on high-fat diets. Using Mcu inhibitors and CRISPR-Cas9-mediated Mcu knockdown, the research shows enhanced mitochondrial biogenesis and energy metabolism, leading to reduced obesity, better glucose tolerance, and insulin sensitivity.
• A new CRISPR-Cas9 method has been developed for studying gene regulation in primary human islet cells, which is critical to understanding diabetes. This technique, involving electroporation of Cas9 ribonucleoprotein and guide RNAs, successfully edits both coding and non-coding DNA linked to diabetes risk. It proved effective in simultaneously targeting PCSK1 regulatory elements, affecting β cell function and insulin secretion.

Industry

• Tune Therapeutics has presented data supporting its chronic Hepatitis B Virus (HBV) program, demonstrating the ability to silence essential mechanisms of viral replication and persistence durably across a range of model systems. The company's CRISPR epigenome editing approach demonstrated near-complete viral DNA repression in primary human hepatocytes and cell lines in vitro and in a mouse model in vivo.
• Prime Medicine and Myeloid Therapeutics have announced the resolution of their outstanding disputes, signalling an end to the pending arbitrations and a positive outcome for both parties. The two companies collaborated until September 2023, when a dispute over breached agreements and milestone payments terminated the collaboration.
• Precision BioSciences has announced the completion of a strategic transaction with TG Therapeutics for an exclusive license to develop Azercabtagene Zapreleucel (azer-cel) for autoimmune diseases and other indications outside of cancer. Azer-cel is an allogeneic meganuclease-edited CD19-targeting CAR-T cell therapeutic candidate initially designed to treat relapsed or refractory non-Hodgkin lymphoma.
• Vertex Pharmaceuticals announces approval of CASGEVY, the first CRISPR/Cas9 gene-edited therapy, for treating sickle cell disease (SCD) and transfusion-dependent beta-thalassemia (TDT) in Saudi Arabia. Saudi Arabia has among the highest prevalence rates of SCD and TDT in the world, with thousands of patients living with these genetic blood disorders.
• CRISPR Therapeutics has announced its strategic priorities and outlook for 2024, including main projects like CASGEVY, hemoglobinopathies, immuno-oncology and autoimmune disease. The company begins the year with approximately $1.9 billion in cash.
• Beam Therapeutics has issued a statement highlighting its progress across the company's base editing portfolio and outlining anticipated milestones in 2024. The company has multiple ongoing ex vivo clinical programs, including BEAM-101 for sickle cell disease (SCD), and will accelerate its in vivo program for alpha-1 antitrypsin deficiency (AATD). Beam starts 2024 with approximately $1.2 billion in cash.
• Repare Therapeutics has provided a corporate update and highlighted key milestones anticipated in 2024. In the coming year, the company will initiate a phase 1 dose escalation study of RP-1664, a potential first-in-class oral PLK4 inhibitor, in adult and adolescent patients with TRIM37-high solid tumours. Repare starts 2024 with approximately $223 million in cash.
• Editas Medicine highlights its anticipated 2024 milestones that include continued enrollment and dosing in the RUBY and EdiTHAL clinical trials of renizgamglogene autogedtemcel (reni-cel), an experimental gene editing medicine under investigation for the treatment of severe sickle cell disease (SCD) and transfusion-dependent beta-thalassemia (TDT).
• Charles River Laboratories has received regulatory approval to manufacture CASGEVY at their Memphis facility. In recent years, the company has significantly broadened its cell and gene therapy portfolio with a substantial good manufacturing practice (GMP)-compliant commercial-ready capacity expansion and the integration of several strategic acquisitions to simplify complex supply chains and meet growing demand for plasmid DNA, viral vector, and cell therapy services.

CRISPR screens

• American researchers have used CRISPR-based screening to show that DHX9 potently represses the innate immune response in small cell lung cancer (SCLC) cells through double-stranded RNA (dsRNA) repression. DHX9 depletion in vivo by an inducible system in SCLC cells triggered an innate immune response, resulting in a more immunogenic tumour microenvironment, increased DNA damage and replication stress in SCLCs, and decreased tumour growth.

Detection

• Chinese researchers have developed a new method for susceptible detection of miRNA-21, a non‐specific biomarker of all maladies. The photoelectrochemical biosensor employs rolling circle amplification-assisted CRISPR-Cas12a dual-cleavage and possesses excellent selectivity, stability and repeatability.
• A novel detection method based on CRISPR-Cas13a targets the repeated DNA sequence of Trichomonas vaginalis and is a convenient, rapid, stable, and accurate diagnostic tool for the pathogen. The method employs multi-enzyme isothermal rapid amplification (MIRA) and lateral flow device (LFD).
• Researchers in China have developed a rapid and sensitive CRISPR-Cas12a-based method for detecting Fusobacterium nucleatum. The method employs fluorescence and lateral flow immunoassay and can complete the detection within 30-40 minutes.

Reviews

• CRISPR-Cas system: A promising tool for rapid detection of SARS-CoV-2 variants. This review discusses strategies for mutation site selection and using CRISPR-Cas, offering valuable insights for developing mutation detection methods.
• Development of Cas13a-based therapy for cancer treatment. This review introduces the mechanism and research developments associated with the CRISPR-Cas13a system in tumour treatments and its potential to be used as a new tool for gene therapy.
• Comprehensive review of CRISPR-based gene editing: mechanisms, challenges, and applications in cancer therapy. This review discusses the challenges and limitations that must be overcome, such as off-target effects, safety, and delivery to the tumour site.

Perspectives

• An editorial in ACS Synthetic Biology discusses how CRISPR systems have revolutionised point-of-care diagnostics. CRISPR-based diagnostics, mainly using Cas12 and Cas13, are advancing point-of-care (POC) molecular diagnostics, especially for infectious diseases like COVID-19. These technologies enable sensitive, specific detection of pathogens and genetic markers. Despite their potential, challenges in affordability, sensitivity, and ease of use still need to be addressed for global application.

Conferences and webinars

• Early bird discounted fees for the CRISPR Medicine Conference in Copenhagen on 23-25 April 2024 will soon expire, so hurry up to secure your ticket for the first European CRISPR conference ever. The event will bring European CRISPR research to the forefront, with six main tracks that cover the most important topics in the therapeutic gene-editing field: Tools, Delivery, Safety, Functional Genomics, Standards and Regulations, Pre-clinical Research and Clinical Trials.

News from CRISPR Medicine News

• Our weekly clinical update on Wednesday reported that Fate Therapeutics has initiated patient enrolment for a Phase 1 clinical trial of FT825/ONO-8250 in solid tumours that express the human epidermal growth factor receptor 2 (HER2). HER2 is a receptor tyrosine kinase overexpressed by many solid tumours, including breast, gastric, bladder, and lung cancers.