Genetic Engineering Publications - GEG Tech top picks

Modified cells survived 19 months after transplant into an HIV-positive man in China, but the dose was not enough to reduce his viral load.

Here, the authors review historical cases of CCR5-edited cell-based therapies, current clinical trials and future benefits and challenges associated with this technology.

In this work, the scientists have co-injected Cas9 mRNA, gRNAs, and donor DNA, they successfully introduced the naturally occurring CCR5Δ32 allele into early human 3PN embryos. In the embryos containing the engineeredCCR5Δ32 allele, however, the other alleles at the same locus could not be fully controlled because they either remained wild type or contained indel mutations. This work has implications for the development of therapeutic treatments of genetic disorders, and it demonstrates that significant technical issues remain to be addressed. The authors advocate preventing any application of genome editing on the human germline until after a rigorous and thorough evaluation and discussion are undertaken by the global research and ethics communities.

In this report, the scientists designed two different gRNA combinations targeting both CXCR4 and CCR5, in a single vector. The CRISPR-sgRNAs-Cas9 could successfully induce editing of CXCR4 and CCR5 genes in various cell lines and primary CD4+ T cells. Using HIV-1 challenge assays, they demonstrated that CXCR4-tropic or CCR5-tropic HIV-1 infections were significantly reduced in CXCR4- and CCR5-modified cells, and the modified cells exhibited a selective advantage over unmodified cells during HIV-1 infection. The off-target analysis showed that no non-specific editing was identified in all predicted sites. In addition, apoptosis assays indicated that simultaneous disruption of CXCR4 and CCR5 in primary CD4+ T cells by CRISPR-Cas9 had no obvious cytotoxic effects on cell viability.

Researchers in China have reported editing the genes of human embryos to try to make them resistant to HIV infection. Their paper which used CRISPR-editing tools in non-viable embryos that were destroyed after three days is only the second published claim of gene editing in human embryos.