A genetic “Swiss army knife” has been created which could treat incurable hereditary diseases such as cystic fibrosis, sickle cell anaemia, and Parkinson’s.
The technology is an improvement on the ground-breaking Crispr gene-editing procedure first developed in 2012, which is arguably the most powerful medicinal tool ever created. Crispr has enormous potential as a treatment, but one issue holding it back is that Cas9 — the bacteria-derived enzyme that cuts and replaces faulty or undesirable genes — is too big to be easily packaged, limiting its uses.
Finding a smaller, but just as effective, the alternative has been a priority for several years. A team of researchers from Stanford University focused on Cas14, a pint-sized relative of Cas9 that has less than half the bulk. However, it does not naturally work in mammals. Dr. Lei Qi and his team attempted to genetically manipulate the Cas14 enzyme to fix this and called their creation CasMINI.
“There were previous efforts from others to improve the performance of working CRISPRs. But our work is the first to make a non-working one working,” said Dr. Qi. “This is a critical step forward for CRISPR genome-engineering applications,” added senior study author Stanley Qi.
“The work presents the smallest CRISPR to date, according to our knowledge, as a genome-editing technology. If people sometimes think of Cas9 as molecular scissors, here we created a Swiss knife containing multiple functions. It is not a big one, but a miniature one that is highly portable for easy use.”
The diminutive scale of CasMINI further adds to the arsenal of Crispr technology, making it even easier to use and opening up more diseases for an attack. “The availability of a miniature CasMINI enables new applications,” Dr. Qi says. “It is on our wish list that it will become a therapy to treat genetic diseases, to cure cancer, and to reverse organ degeneration.”
SOURCE: SOURCES: REUTERS, NATURE, MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Professors Emmanuelle Charpentier and Jennifer Doudna, the co-discoverers of CRISPR-Cas9, won the Nobel Prize in Chemistry last year for their work. They found that bacteria have a primitive immune system that uses a protein called Cas9 to defend against viruses and it does this by cutting up the invading virus’s DNA.
The scientists managed to harness this ability to precisely target and remove faulty or undesirable genes at a whim by attaching them to a genetic guide. The potential for this technology is enormous and opens the door for scientists and doctors to target the root cause of many incurable and heritable conditions. The use of CRISPR on humans has been heavily limited to a smattering of studies, with people worried about its long-term effects, safety, and the ethical implications of “playing God”.
Instances of illegal use on people have been recorded and the most notorious example is disgraced scientist He Jiankui, who used Crispr on the embryos of two unborn twin girls in a bid to make them HIV resistant.
However, despite the ethical concerns, scientists are keen to exploit its potential as a weapon against disease.
The findings have been published in the journal Molecular Cell.