CRISPR, a tool for editing the genetic code in living organisms, was first discovered in 2007. Since then, the prospect of eliminating disease by editing the human genome has hovered on the edge of science fiction and reality.
Until 2020.
Here are four incredible CRISPR breakthroughs that happened this year.
Better precision with a small protein
“When we think about how CRISPR will be applied in the future, that’s really one of the main bottlenecks for the field right now: delivery,” said Jennifer Doudna, who won the Nobel Prize in Chemistry in October with Emmanuelle Charpentier creating CRISPR, Genetic Engineering told News.
Accessing DNA in living cells has been the biggest challenge for CRISPR. The most commonly used CRISPR gene editing system uses a protein called Cas9, which is naturally found in bacteria and archaea. Their biological role is to fight viruses by destroying the viruses’ DNA and cutting it from their genomes.
However, scientists can use them as “DNA scissors,” which can be used to cut pathogenic mutations from any DNA.
The problem is that Cas9, as well as other proteins used in various CRISPR systems, are all very bulky, making it difficult to access the tiniest nooks and crannies of the human genome.
However, in July, Doudna and her University of California Berkeley team announced they had found a new Cas protein.
Drumroll please. Enter the small CasΦ (pronounce “Cas-phi”).
At practically half the size, CasΦ can reach areas of the human genome that most CRISPR gene editing proteins cannot. This new protein could be a game changer for genetic engineering.
Gene therapy seen as a cure for sickle cell disease
This year, researchers announced the results of an ongoing clinical trial testing the ability of CRISPR to process the DNA of living cells and potentially cure genetic diseases in humans.
The study focused on two of the most common genetic conditions worldwide: sickle cell disease and beta thalassemia. The only cure for these blood diseases is through a stem cell transplant from a viable donor. But often recipients have to take immunosuppressants for months or years, with difficult side effects.
The tests involve collecting blood stem cells from the patients. Next, researchers used CRISPR to change the genes of the cells, and finally they transplanted the stem cells back to the patients. Several months later, when patients reported that their symptoms were gone, the scientific community hailed the study as a breakthrough in gene therapy – calling it a cure.
“I am encouraged by the preliminary results, which essentially demonstrate a functional cure for patients with beta thalassemia and sickle cell disease,” said researcher Haydar Frangoul in a press release.
The next step is to expand the study by enrolling 45 patients and observing them for a long time.
Genetically modified pigs can be future organ donors
The US does not have enough donor organs to meet all needs. As a result, about 17 people die every day because they couldn’t get the liver, heart, or lung they needed.
To overcome this deficit, scientists have been investigating inter-species donations – or xenotransplantation – for a decade with little progress. Our immune system is designed to attack invaders, which is great if you have the flu, but it makes xenotransplantation practically impossible.
“The approach, if validated by further studies, could help address global organ deficiency (s) to alleviate transplant needs.”
George Church
Now, thanks to CRISPR, xenotransplantation could be possible. Using CRISPR, researchers at Qihan Biotech have modified the DNA of pigs to make them more compatible with humans. The researchers made 13 genetic modifications to the pigs, all in hopes of making them more acceptable to the human body. In vitro laboratory tests showed promise: cells from the gene-edited pigs appeared to be less likely to be rejected by the human immune system than those from non-modified animals.
“The approach, if validated by further studies, could help resolve global organ deficiency (s) to alleviate transplant needs,” George Church, co-founder of Qihan Biotech, said in a release.
Further studies are underway: The team is now testing an organ transplant from a gene-edited pig into a primate.
CRISPR enters the human body for the first time
Scientists at the Casey Eye Institute in Portland used CRISPR for the first time in the human body – on a patient with a hereditary form of blindness.
Doctors dropped the gene-editing tool behind the retina via three drops of fluid passed through a tube the size of a human hair. Once in the body, CRISPR went to work. It cut the mutated gene on both sides of the problem area. They hope that once the mutation is removed, the cut DNA will rejoin itself, allowing the gene to function as it should. They are now in clinical trials.
“Once the cell is processed, it is permanent and hopefully that cell will preserve the patient’s life,” because these cells do not divide, said a study leader not involved in this first case, Dr. Eric Pierce of Massachusetts Eye and Ear.
If everything goes according to plan, the patient should see it again in a few months. Next, the doctors plan to further test the procedure on 18 children and adults.
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