- Recent developments in gene editing have raised ethical questions
- Precision gene editing could help fight deafness
- Gene editing could help reverse the ageing process
- Can gene editing help with the early detection and treatment of autism?
- CRISPR genome editing: concerns and future prospects
Unclear regulatory measures surrounding gene editing has made it one of the most controversial topics in the world of science in the past decade. This method of altering our genetic makeup involves using a gene-editing tool called CRISPR to add, remove, or alter genes to modify the function of a targeted DNA sequence. And the scope of altering organisms’ DNA is impressive. From developing more potent drugs to designing more resilient crops, CRISPR genome editing technologies could be a powerful tool to eradicate diseases previously believed incurable.
According to a recent report published by Business Wire, the value of the Europe genome editing market is expected to reach $3.4 billion by 2025, growing with a compound annual growth rate (CAGR) of 16.7% between 2018 and 2025. The market growth is driven by the recent technological advancements in genomics, up-and-coming applications of various types of CRISPR therapies, and, among other things, a more favourable regulatory environment accompanying the changing perception of gene-editing technologies in the past couple of years.
Recent developments in gene editing have raised ethical questions
In 2019, the European Commission and the European Group on Ethics in Science and New Technologies (EGE) organised a roundtable event on the ethics of gene editing. The event gathered a broad spectrum of stakeholders drawn from academia, industry, policy and civil society, to discuss the ethical questions raised by recent developments in gene editing, such as CRISPR-Cas9, across all domains of application including human health, agriculture, and the environment.
There’s still a lot to be learned about the implications of genome editing applications in humans, animals and plants, however. The EGE is currently developing a set of policy recommendations that will soon provide some clarity on the ethical aspects of this cutting-edge tech. What is clear, however, is that gene editing will play a major role in the future and its relevance for humankind is undeniable, as one of the speakers at the roundtable, Professor Christiane Woopen, pointed out. “What is so special about gene editing? It’s a technology that in principle is easy to apply, cheap and precise. Thus, pragmatic obstacles disappear in favour of a low threshold and broad application. Thus, far reaching questions arise,” emphasising that “we have to discuss, amongst other issues, our concepts of nature and naturalness, their moral significance and our role in shaping it”.
Precision gene editing could help fight deafness
According to the latest data provided by the World Health Organisation (WHO), almost 470 million people worldwide struggle with hearing problems. In the EU alone, nearly 35 million people live with a disabling hearing loss. Early diagnosis can help prevent or minimise hearing loss, which, by 2050, could affect nearly 900 million people worldwide, estimates WHO.
Hearing loss can have many causes, some of which include chronic ear infections, exposure to excessive noise, complications at birth, ageing, and genetic predisposition. Besides a lower quality of life and decreased productivity, disabling hearing loss costs the EU €185 billion each year. And even if we disregard the financial burden of the disability, we cannot ignore the fact that millions around the world don’t enjoy life to the fullest due to partial or complete deafness. This, however, could soon change, thanks to the latest breakthroughs in gene editing.
A team of researchers from Boston Children’s Hospital and the Broad Institute of MIT and Harvard, has managed to restore hearing in mice using base editing. It’s a novel gene editing approach that combines CRISPR systems with enzymes. This enables point mutations to be installed with more precision into cellular DNA or RNA without making double-stranded DNA breaks (DSBs). These DSBs can lead to cell death or cause genome mutagenesis but the team found a way around this. The base editor sequence that engineers the genetic repair was split up into two adeno-associated viruses (AAVs), proving more efficient. “Once the cell was infected with these two parts, it reassembled into a single full length sequence and performed the base editing task we needed,” explains co-first author Olga Shubina-Oleinik, of the Holt lab, noting that “when we got both into the cells, we went from zero function to 100 percent. That tells me all we need to do is get it into more cells and we will recover more hearing function.”
Given that 34 million children worldwide have disabling hearing loss, the importance of the breakthrough is immense. “This research is very important for the pediatric community here at Boston Children’s Hospital and elsewhere because about 4,000 babies are born each year with genetic hearing loss,” says Jeffrey Holt, co-senior author on the study. “And, we feel this is a big step beyond the field of hearing restoration and for the broader field focused on treatment of genetic disorders.”
Gene editing could help reverse the ageing process
David Liu, a Howard Hughes Medical Institute (HHMI) Investigator at Harvard University and his team, together with their collaborators at the National Institute of Health and Vanderbilt University, are excited to report that they have made significant progress correcting the genetic error that causes progeria, a rare disease behind rapid aging and premature death. Despite not being complete, the study is definitely promising. This, however, is not the only attempt at slowing down the ageing process.
Researchers at Salk Institute developed a gene therapy that could, one day, promise a wrinkle-free life. Just like Liu’s team, they observed mice with progeria, to gain insight into molecular pathways related to accelerated ageing. They noticed that one of the main causes of this degenerative disorder is a mutation in the LMNA gene known to provide instructions for making proteins called lamin A and lamin C, made up of a nearly identical sequence of amino acids. Unfortunately, progeria changes the production of lamin A into progerin which is responsible for premature ageing. This is where gene editing proves an almost ideal solution. The team used the CRISPR toolbox to deliver two synthetic guide RNAs that lead the Cas9 protein to a specific location on the DNA strand to make progerin nonfunctional. This way genetic degeneration is prevented. Izpisua Belmonte, holder of the Roger Guillemin Chair, is optimistic, but still emphasises that the treatment needs to be perfected.
“This is the first time a gene editing therapy has been applied to treat progeria syndrome. It will need some refinements, but it has far fewer negative effects compared to other options available. This is an exciting advancement for the treatment of progeria.”
Can gene editing help with the early detection and treatment of autism?
Globally, one in 160 children is diagnosed with an autism spectrum disorder. And while some can live independently and enjoy a reasonably good quality of life, others require life-long support and psychosocial interventions. Early diagnosis can help to start with timely treatment, and researchers at the University of North Carolina at Chapel Hill now claim they can detect the disorder before the first symptoms appear. The team has been working on treatments for some of the conditions that make coping with the disorder ever more challenging. Understanding the genetic basis for detecting autism is crucial for outlining a possible treatment.
They discovered that a mutation in the maternal UBE3A gene causes Angelman syndrome, a rare neurodevelopmental disorder that’s on the autism spectrum. The other parent’s gene that’s in pristine condition but ‘silenced’ or inactive, could be used to replace the maternal UBE3A gene. This way a child could be born without the disorder. Mark Zylka, director of the Neuroscience Center at UNC, says that CRISPR-Cas holds a lot of potential. “CRISPR-Cas technology can be used to turn genes off or on. Since many cases of autism are due to loss of one copy, you still have a second copy that is functional. And so you could use an editing approach to turn on the functional copy to a higher level.” However, this approach demands caution moving forward, as David Segal, a professor of chemistry at the University of California, Davis, points out. “The idea that you could treat a fetus with [an enzyme] is just a very uncharted area, and could contain a lot of risks. We need to move with caution.”
CRISPR genome editing: concerns and future prospects
Genome editing has been one of the most controversial topics in the world of science in the past decade, and even though there have been some recent breakthroughs in the field, the controversy surrounding the practice isn’t likely to diminish anytime soon. In fact, every step forward is taken cautiously, and understandably so, since gene editing is still largely uncharted territory. Also, unclear legislation and policies don’t contribute to approving more research and open doors to wider applicability. We do need more information and more research, however, to prove CRISPR safe. So far, the results are promising, and perhaps, thanks to this technology, we might live in a disease-free world one day, where getting older won’t mean becoming weak.
