Chinese biologists say they have created an ethical technology to edit RNA – a molecule essential in coding, decoding and expression of genes. They claim it will have “no heritable impact” and thus carries no ethical consequences.
The novel gene-editing tool, developed by and being trialed at the Shanghai Institute of Neuroscience under the Chinese Academy of Sciences, was first made public in July when the prestigious Nature Biotechnology magazine ran a paper about the new technology.
Chinese geneticists appear eager to make up for the stigma created by their peer He Jiankui – a professor with the Shenzhen-based Southern University of Science and Technology – who altered human zygotes that led to the birth of twins said to be immune to HIV and AIDS in 2018.
He’s high controversial experiments caused a commotion among academics around the world and brought Chinese gene research into disrepute.
The technology He applied was CRISPR-Cas9, adapted from a naturally occurring genome editing system in bacteria. Cas9 enzyme – a protein that plays a vital role in the immunological defense against DNA viruses – was introduced into the human body to cut and edit the viruses’ DNA.
Such technology relies on the delivery of exogenous proteins or chemically modified RNAs that can act as a guide, which may lead to aberrant effector activities, delivery barrier or immunogenicity, according to Wei Wensheng, a Peking University biologist and lead scientist of the team that developed the new tool. Wei spoke to the People’s Daily about the many deficiencies of He’s approach and activities.
However, the latest technology, called endogenous programmable editing of RNA, makes use of native proteins and will not change DNA directly. So, it would not bring about any heritable changes, according to the scientist, whose team is currently conducting tests on lab rats.
Specifically, the new technology employs engineered RNAs to recruit native enzymes to turn a specific adenosine into inosine, and, as a single-molecule system, the new tool enables precise, efficient RNA editing with broad applicability for therapy and basic research, according to the Nature Biotechnology website.
While ensuring no heritable changes, cellular-level experiments over the past two years have also verified the effectiveness of the gene-editing tool with a success rate of about 80%.
The tool is active in and applicable to a broad spectrum of cell types, including multiple human primary cell types, and can allegedly restore the deficient or malfunctioning cells of patients with Hurler syndrome, without evoking innate immune responses.