A revolutionary gene editing technique hailed as the future of disease eradication and mooted for a Nobel prize may be less precise and cause more cell damage than previously thought, researchers said Monday.
Lab experiments using mouse and human cells revealed that the CRISPR-Cas9 technique “frequently” caused “extensive” gene mutations, a study team reported.
“This is the first systematic assessment of unexpected events resulting from CRISPR-Cas9 editing,” said Allan Bradley of the Wellcome Sanger Institute in England, where the team conducts research.
The research showed that “changes in the DNA have been seriously underestimated before now,” said Bradley, who co-authored a study published in the journal Nature Biotechnology.
The mutations have not been shown to be harmful, nor benign.
“It is important that anyone thinking of using this technology for gene therapy proceeds with caution and looks very carefully to check for harmful effects,” Bradley said in a statement issued by the institute.
First unveiled about six years ago, CRISPR-Cas9 allows scientists to insert, remove and correct a faulty sequence on a strand of DNA in a cell with pinpoint precision.
It has raised hopes that one day disease-causing genes could be removed or altered before a baby is even born.
In recent years, CRISPR-Cas9 has repeatedly been predicted to win the Nobel chemistry prize.
CRISPRs — clustered regularly interspaced short palindromic repeats — are part of the immune defence system in bacteria, used to hone in on the exact spot on the genome where the cut should be made.
Cas9 is a protein used as “scissors” to snip through the faulty gene, which is then replaced or fixed by the cell’s own DNA repair mechanism.
– ‘Safety implications’ –
The technique’s safety has not yet been proven, and it is not approved for use in human therapy.
So far, researchers have used it to improve hearing in mice going deaf and to fix a disease-causing mutation in cloned, early-stage human embryos.
But the new finding raises “safety implications,” the team said.
They found “large genetic rearrangements such as DNA deletions and insertions” in cells, which could lead to important genes being switched on or off and causing dangerous changes.
The research also showed that standard tests do not pick up damage to DNA caused by CRISPR-Cas9.
Experts not involved in the study said it was unclear how such large, unintended changes were not noticed before.
But, “the results give no reason to panic or to lose faith in the methods when they are carried out by those who know what they are doing,” said Robin Lovell-Badge of The Francis Crick Institute, a biomedical research centre in London.
For Francesca Forzano, a consultant in clinical genetics and genomics with the Guy’s and St Thomas’ NHS Foundation Trust, the work showed that CRISPR-Cas9 “is much less safe than previously thought” and that safety-monitoring techniques were “not entirely adequate”.
More research is needed before any clinical application of the method is considered, said Forzano.
‘Outrageous and criminal behavior’: Internet blows up at graphic video of Buffalo Police pushing over an elderly man
On Thursday, footage emerged of police in Buffalo, New York pushing an elderly man to the ground, and refusing to help him as he lay bleeding profusely from a head injury.
The footage triggered immediate outrage on social media.
Horrible. I pray he’s ok. https://t.co/wL2gcNeAIT
— Joe Walsh (@WalshFreedom) June 5, 2020
WATCH: Protester bled from his ear after being shoved by police — cops say he ‘tripped’
SHocking video from Buffalo, New York was posted online on Thursday after a large group of police confronted a lone protester -- and then violently shoved him.
"Shortly after Buffalo’s curfew started, city police and State Police swept through the area of Niagara Square directly in front of City Hall to clear the area where a protest was finishing. An unidentified, older man was hit shoved by two officers in the line. The man lost his balance and fell to the pavement, audibly hitting his head with blood running out from under his head," WBFO-TV reports.
Trump aides are compiling candidates to replace Mark Esper if Trump decides to fire him: report
On Thursday, Politico reported that although Defense Secretary Mark Esper's job appears safe for now, aides to President Donald Trump are compiling a list of potential nominees to replace him if the president changes his mind and decides to fire him.
"An administration official and two people close to the White House say staffers in recent days have pulled together a list of possible candidates for Defense secretary if Trump does choose to fire Esper," reported Lara Seligman, Daniel Lippman, and Meridith McGraw. "At the top of that list is Army Secretary Ryan McCarthy, who was Esper’s No. 2 before taking the Army job last summer, the people said. Sen. Tom Cotton (R-Ark.), an outspoken Trump ally who has previously been considered for the position, is also in the mix, according to one of the people."