CMN Weekly (29 October 2021) - Your Weekly CRISPR Medicine News

Top picks

• Nanoparticle-sensitised photoporation, just or photoporation, is a promising upcoming physical transfection method for delivering macromolecules such as DNA, RNA or proteins in vitro or ex vivo. Researchers from Belgium and China now demonstrate that photothermal nanofibres can successfully deliver CRISPR–Cas9 ribonucleoprotein complexes to adherent and suspension cells. This includes embryonic stem cells and hard-to-transfect T cells without affecting cell proliferation or phenotype.
• CRISPR-pioneer Virginijus Siksnys and colleagues have biochemically characterised two miniature types V-F Cas nucleases, SpCas12f1 (497 aa) and AsCas12f1 (422 aa). The findings might pave the way for the development of miniature Cas12f1-based genome editing tools.

Research

• The crystal structure of the anti-CRISPR protein, AcrIIC4, has been elucidated by researchers in Korea. The structure revealed that AcrIIC4 exhibits a helical bundle fold comprising four helixes that interacts directly with Cas9 and Cas9/sgRNA complex in its monomeric form.
• Researchers from China have elucidated the structural basis for anti-CRISPR (Acr) repression mediated by bacterial operon proteins Aca1 and Aca2. The results also shed light on understanding the repression roles of other Aca family proteins and the autoregulation roles of acr-aca operons.
• American researchers have developed a method for effective AAV5 delivery of CRISPR/Cas9 components to the lung. The technique involved intratracheal injection and was used for editing of a lox-stop-lox-Tomato reporter in mouse lung airway. The team observed ∼19–26% Tomato-positive cells in large and small airways, including club and ciliated epithelial cell types.
• An ultrasensitive method for detecting citrinin - a mycotoxin that is often found in food - has been developed by researchers in China. The technique combines double isothermal amplification with CRISPR-Cas12a and relies on antigen-modified gold nanoparticles that compete with citrinin to bind to magnetic beads coated with an anti-citrinin antibody.
• A paper from the preprint server bioRxiv describes a CRISPR-Cas9-based system for the dose-dependent study of DNA double-strand breaks sensing and repair. The French researchers exploit the repetitiveness of the Ty transposon elements in the genome of Saccharomyces cerevisiae and the cutting activity of the RNA-guided Cas9 nuclease to create a tool that combines sequence specificity and dose-dependency.
• Chinese researchers have used CRISPR to correct an RNA splicing defect in mice with β⁶⁵⁴-thalassemia - a prominent Chinese subtype of β-thalassemia. Gene editing was performed in mouse embryos, and 83% of live-born mice were gene-edited, 70% of which produced correctly spliced RNA.

Industry

• Vertex and Mammoth Biosciences have announced a deal that allows Vertex to use Mammoth’s proprietary ultra-small CRISPR systems - including Cas14 and Casɸ - to discover and develop novel in vivo gene-editing therapies. Under the agreement terms, Mammoth Biosciences will receive upfront payments of $41 million and is eligible to receive up to $650 million in potential future payments.
• ElevateBio, a cell and gene therapy technology company, has acquired full ownership of Life Edit Therapeutics. Life Edit has one of the world's largest and most diverse arrays of novel RNA-guided nucleases and base editors active in mammalian cells.

Clinical News

• The FDA has granted orphan drug designation to Intellia Therapeutics' NTLA-2001 to treat transthyretin (ATTR) amyloidosis. NTLA-2001 is an in vivo investigational CRISPR therapy that knocks out the transthyretin (TTR) gene and reduces the concentration of TTR protein in serum.
• FDA has placed Gamida Cell's GDA-201 on hold pending modifications to donor eligibility procedures and sterility assay qualification. GDA-20 is a cryopreserved, off-the-shelf cell therapy candidate for treating patients with follicular and diffuse large B cell lymphomas. The company recently submitted an IND application to FDA for a Phase 1/2 trial with GDA-201.

COVID-19

• In a not yet peer-reviewed paper, Chinese researchers report a method for rapid and accurate detection of Sars-SoV-2 mutations such as 69/70 deletion, N501Y, and D614G. The method employs Cas12a-based RT-PCR and can differentiate mutant variants with a sensitivity of 10⁻¹⁷ M (approximately 6 copies/μL).

Reviews

• A review by researchers from India focuses on the possible impact of CRISPR-Cas systems in regenerative medicines. They provide a detailed description of the CRISPR based regenerative therapeutic approaches for a horde of diseases like genetic disorders, neural diseases, and blood-related diseases is elucidated.

Opinion and Prizes

• The Nature journal has awarded the 2021 Nature Research Award for Inspiring Women in Science in the Scientific Achievement category to Dr Kiana Aran, associate professor at Keck Graduate Institute, California, and Chief Scientific Officer at Cardea Bio. Within the CRISPR Medicine field, Kiana Aran is probably best known for the invention of the CRISPR-Chip. Read our take on the award here.
• A paper in the Journal of Law and the Biosciences discusses the CRISPR patent rivalry and ethical licensing. The Greek authors argue that universities can emerge as important actors in the regulatory enterprise through additional ex post-licensing. They propose a market-based solution in the form of a license allowing for patent re-licensing if the licensee fails to address a predefined demand for the final product.

Huh, heh, wow

• A pig kidney with a xenoantigen deletion has been transplanted into a recently deceased human with an intact circulation. The organ performed well for at least 54-hours without immediate hyperacute rejection by the recipient. Recombinetics and its regenerative medicine division, Makana Therapeutics, used gene editing to delete the alpha-Gal epitope present in the pig's kidney, which is known to be a key xenoantigen that elicits xenorejection.