In this week's Nature, a team led by Harvard University researchers reports the use of CRISPR-Cas9 genome editing to treat hearing loss in a mouse model of deafness. The scientists created lipid-encapsulated CRISPR molecules that could preferentially disrupt the dominant deafness-associated allele of a hearing loss gene, and administered them directly into the cochlea of the mice. The treatment resulted in a substantial reduction in progressive hearing loss, as well as higher hair cell survival rates and lower auditory brainstem response thresholds in injected ears versus controls. The findings point to a potential new treatment for some types of autosomal dominant hearing loss. The Scan also has more on this, here.
In Nature Communications, two independent research teams publish studies identifying new subgroups of juvenile myelomonocytic leukemia (JMML) — an aggressive form of childhood cancer — that can predict patient outcomes. In the first report, the scientists analyzed DNA methylation patterns and mutation profiles of 167 JMML samples, identifying distinct subgroups with low, medium, or high levels of methylation. Patients in the high methylation group had poor clinical outcomes, while the low methylation group had good prognoses. In the second paper, investigators looked at DNA methylation of 39 patients and found similar associations between methylation levels and outcomes.
Lastly, in Nature Genetics, a group of Chinese scientists describes the single-cell DNA methylome sequencing of human preimplantation embryos, identifying tens of thousands of genomic loci exhibiting de novo DNA methylation. The finding indicates that "genome-wide DNA methylation reprogramming during preimplantation development is a dynamic balance between strong global demethylation and drastic focused remethylation," they write. They also show that the genetic lineage of early blastomeres can be traced by DNA methylation analysis. GenomeWeb has more on this study, here.