CMN Weekly (27 January 2023) - Your Weekly CRISPR Medicine News

Some of the best links we picked up around the internet

By: Gorm Palmgren - Jan. 27, 2023

Top picks

TALEN gene-edited allogeneic CAR T cells show feasibility and preliminary efficacy for treating multiple myeloma in interim results from the phase 1 UNIVERSAL trial. Of forty-three patients treated with the ALLO-715 therapeutic product, 56% showed an objective response and a median response duration of 8.3 months. While adverse events grade ≥ 3 occurred in 88% of patients, these were mainly haematological conditions (12-70% of patients). Other grade ≥ 3 adverse events occurred as infections in 23% of patients, cytokine release syndrome in 2% and neurotoxicity in 0%. TALEN gene editing was used to abolish the expression of TRAC and CD52, thereby reducing graft-versus-host disease and increasing CAR T cell survival, respectively.
Exa-cel, the CRISPR based therapeutic for treating sickle cell disease (SCD), has moved closer to the market in the EU. The European Medicines Agency (EMA) has validated a marketing authorisation application from Vertex and CRISPR Therapeutics that has co-developed exa-cel. Exa-cel, formerly known as CTX001, is an autologous treatment that uses CRISPR-Cas9 in the patient's own haematopoietic stem cells, so they produce high levels of fetal haemoglobin (HbF) in red blood cells.

Research

Jennifer Doudna and colleagues have adapted the RNA-guided RNA-targeting type III CRISPR-Csm complex from S. thermophilus for programmable targeting of transcripts in human cell cultures. The system has significant advantages over RNAi or CRISPR-Cas13 as the RNase-active complexes can knock down cytoplasmic or nuclear-localised transcripts. In contrast, the RNase-inactive complexes can be used for live imaging in cells.
Researchers in the Netherlands have demonstrated a robust and easy strategy to improve precise gene editing by chemical inhibition of end-joining pathways after CRISPR-Cas9-induced DNA double-strand breaks. The researchers used two chemicals, NU7441 and ART558, to inhibit non-homologous end joining (NHEJ) and polymerase theta-mediated end joining (TMEJ), respectively, thereby increasing the efficiency of homology-driven repair (HDR)-mediated precise gene editing.

Industry

KSQ Therapeutics announced that Ono Pharmaceutical has acquired its CRISPRomics platform technology in multiple research-stage oncology programs to discover novel therapeutic targets with high selectivity for cancer cells. The CRISPRomics discovery engine enables genome-scale, in vivo validated, unbiased drug discovery across broad therapeutic areas.
Cellectis has amended specific financial terms of the $20 million convertible note issued by its partner, Cytovia Therapeutics. The payment covers the upfront collaboration consideration provided under the research collaboration and non-exclusive license agreement between Cellectis and Cytovia.

Detection

A thorough comparison between two Sars-CoV-2 assays on CRISPR and RT-PCR shows that the two methods have comparable performance. The CRISPR test achieved 98% sensitivity and 100% specificity, while the RT-PCR test achieved 100% sensitivity and 100% specificity. However, the CRISPR test showed several advantages, including short assay time, low cost, and no requirement for expensive equipment.
Chinese researchers have developed a fluorescent aptasensor system for detecting nasopharyngeal carcinoma-derived exosomes. The system is based on combining magnetic nanoparticles, terminal deoxynucleotidyl transferase (TdT), CRISPR/Cas12a, and a nucleic acid aptamer. The TdT can form an ultra-long polynucleotide tail which can bind with multiple crRNA, generating a signal amplification effect. The method exhibited excellent sensitivity and specificity, with a linear range between 500 to 5 × 10⁴ particles mL⁻¹ and a detection limit of 100 particles mL⁻¹.
Researchers in China have developed a sensitive fluorescent sensing method for detecting thrombin, a biomarker of cardiovascular outcomes. The detection method integrates the DNA walker and CRISPR-Cas12a system to trigger the nuclease's trans-cleavage activity for cyclically cleaving a fluorescently quenched signal probe. The procedure obtained a detection limit for thrombin of 29.5 fM.
A new digital microfluidic chip (DMF) has been developed for the automated and sensitive detection of pathogens. The method uses CRISPR-Cas12a for target recognition and signal amplification and significantly reduces reagent consumption and analysis time when combined with DMF. The DMF-Cas12a method was applied to assay S. aureus in actual samples.
Chinese researchers present a CRISPR-Cas12a-based method for universal and sensitive gene mutation detection. The technique detected clinically significant mutations in PTEN R130Q, BRAF V600E, and TP53 R248W, with a detection limit of 0.1%. In addition, in 10 clinical samples, the TP53 R248W mutation was detected with an accuracy of 100%.

Reviews

Advances in RT-LAMP for COVID-19 testing and diagnosis. This review by American researchers discusses the role of RT-LAMP within the context of other technologies like RT-qPCR and rapid antigen tests. The focus is on progress in sample preparation strategies to enable simplified workflow for RT-LAMP directly from clinical specimens, new challenges with primer and assay design for the evolving pandemic, prominent detection modalities including colourimetric and CRISPR-mediated methods, and translational research and commercial development of RT-LAMP for clinical applications.