To treat autosomal dominant hearing loss, Chinese researchers have used cell sorting to precisely detect the efficiency of in vivo CRISPR-Cas9 gene editing in hair cells. Until now, it has been almost impossible to evaluate editing efficiencies because the whole cochlear tissue contains many non-target cells. In a mouse model, the authors show that a mutation in Kcnq4 responsible for hearing loss was repaired in 34% of hair cells, while the editing efficiency in the whole cochlear tissue was only 1.5%. Furthermore, gene editing improved hearing in treated animals as evaluated by several parameters.
Researchers in the Netherlands demonstrate how DNA oligonucleotides can effectively inhibit Cas9 activity both ex vivo and in vitro, thereby increasing the safety of genome editing applications. The researchers show in human cells that DNA oligonucleotides can reduce both on- and off-target cleavage. Moreover, in vivo experiments find two critical factors for robust inhibition: the length of the complementary region and the presence of a protospacer adjacent motif-loop on the inhibitor.
Another Chinese research team describes a CRISPR Cas12a-based detection system for miRNA-141. Cas12a is used to initiate a switchable ternary electrochemiluminescence (ECL) biosensor combined with a Co3O4@Au nanoemitter. In addition, a programmable enzyme-free hybrid chain reaction (HCR) amplifier on a paper working electrode (PWE) is used to assemble the nucleic acid tandem and accomplish the secondary recursion of the signal. As a result, the biosensor demonstrates high sensitivity and specificity, with a detection limit of 3.3 FM.
A German research review looks at DNA base editing in nuclear and organellar genomes. The paper gives a comprehensive overview of the base-editing technology, details strategies to improve the efficiency of deaminase-based base editors, and how they can be engineered for altered activity windows or improved specificity and precision.
Researchers in the USA discuss the recent advances in CRISPR-based biosensors for point-of-care pathogen detection. The review gives a detailed background to different CRISPR-Cas effectors and their working principles for disease diagnosis. Moreover, it focuses on developing new signalling mechanisms, eliminating preamplification and sample pretreatment steps, and miniaturising CRISPR reactions on digital assay chips and lateral flow devices.
Engineering off-the-shelf universal CAR T cells is the subject of a review by researchers from India. The paper details the background and challenges of CAR T therapy and discusses strategies for improvement. All 28 ongoing clinical trials with allogeneic CAR T therapies are listed, and their challenges are discussed.