DNA-editing breakthrough could fix 'broken genes' in the brain, delay ageing and cure incurable diseases
DNA-editing breakthrough could fix 'broken genes' in the
brain, delay ageing and cure incurable diseases
‘The possible applications of this discovery are vast,’
scientist says
Ian Johnston Science Correspondent November 16, 2016 9
hours ago
Scientists have discovered a new way to edit DNA that
could fix “broken genes” in the brain, cure previously incurable diseases and
potentially even extend the human lifespan.
The breakthrough – described as a “holy grail” of
genetics – was used to partially restore the sight of rats blinded by a
condition which also affects humans.
Previously researchers were not able to make changes to
DNA in eye, brain, heart and liver tissues.
But the new technique allows them to do this for the
first time and could also lead to new treatments for a range of diseases
associated with the ageing process.
One of the researchers, Professor Juan Carlos Izpisua
Belmonte, said: “We are very excited by the technology we discovered because
it’s something that could not be done before.
“The possible applications of this discovery are vast.”
The cells in most of the tissues of an adult body do not
divide, making it harder for scientists to introduce changes to the DNA.
But Professor Izpisua Belmonte, of the Salk Institute in
the US, said: “For the first time, we
can enter into cells that do not divide and modify the DNA at will.”
“We now have a technology that allows us to modify the
DNA of non-dividing cells, to fix broken genes in the brain, heart and liver.”
“It allows us for the first time to be able to dream of
curing diseases that we couldn’t before, which is exciting.”
The researchers used the technique on rats born with a
genetic disease called retinitis pigmentosa, which affects about one in 4,000
people in the UK.
By altering the genes affecting the eyes, they were able
to give the rats a degree of vision.
“It should be noted, however, that although tests
demonstrated improved visual responses after subretinal injection of [the DNA
repair] to three-week-old … rats, the rescue was only partial and not enough to
completely restore vision,” the researchers wrote in a paper about their
research in the journal Nature.
The technique, known as HITI, was based on the famous
CRISPR gene-editing technique.
“The ability to use HITI for in vivo [in a living animal]
targeted transgene insertion into post-mitotic [non-dividing] neurons is
unprecedented and will help advance basic and translational neuroscience
research,” the paper added.
Scientists who were not involved in the study hailed the
breakthrough.
Professor Robert MacLaren, of Oxford University,
described the research as a “significant advance”.
“Researchers are now using this mechanism to correct gene
defects. Clinical trials are a long way off because the CRISPR proteins may cut
DNA at other sites that may have untoward effects,” he said.
“Nevertheless, since ageing is defined as picking up DNA
mutations, the ability to correct these mutations may in future provide us with
a means of extending our lifespan as well as treating many diseases that relate
to ageing.”
Dr Andrew Wood, of the Institute of Genetics &
Molecular Medicine at Edinburgh University, was similarly impressed.
“This study is a really exciting development for
therapeutic applications of genome editing,” he said.
“Although other groups have applied similar approaches in
dividing cells grown in the laboratory, this is the first time that it has been
used in non-dividing cells in a living animal.
“Before it can be applied to humans, it is now important
to improve the efficiency with which the genome editing molecules can be
delivered to the relevant cells.”
And Dr Helen O’Neill, of the Embryology, IVF and
Reproductive Genetics Group at University College London, said the technique
could enable doctors in the future to use gene editing to treat patients.
“This is an elegant study which establishes new means for
targeted integration of DNA in cells which are no longer dividing,” she said.
“These cells have long been considered a hurdle in
somatic cell therapy.
“Further work will need to be done on improving
efficiencies, but this work certainly shows new avenues for alternative
research into gene therapies.”
Professor Robin Lovell-Badge, of The Francis Crick
Institute and one of the UK’s leading geneticists, said: “As reported, the
methods are not super-efficient. For some genetic diseases it is not necessary
to target all cells within the affected tissue, but levels of five per cent or
so would only give marginal benefit.
“However, with improvements in this type of technology,
which seem inevitable these days, it is likely that the methods developed here
could prove to be a very useful way of adding genes to non-diving cells,
certainly for purposes of basic research, and perhaps eventually for gene
therapy to treat otherwise incurable diseases.
“It is a complicated paper, and it does not quite reach
the level as hyped in the press release, but it is indeed rather important.”
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