[ad_1]
It has been described as one of the most important advances of modern science. But now a new study warns of its dangers.
The technique of genetic publishing CRISPR / Cas9 allows to eliminate and replace sections of DNA in the cells of any organism.
This "cut and paste" technique is already revolutionizing science
but researchers at the Wellcome Sanger Institute in England have found that CRISPR / Cas9 often causes extensive mutations, although localized to some distance from the genome editing site
WHAT CRISPR
? The technique of genetic publishing or short and paste is a technique that allows to cut our genes, "explains the Spanish scientist at BBC Mundo Luis Montoliu research scientist at the National Center of Biotechnology of Madrid
"We have been pioneers in the use of this technology since the beginning, since 2013, although we did not work directly
How did CRISPR / Cas9 happen?
"What we have done has been to adapt the tools that bacteria use to defend themselves against the viruses that infect them and turn them into new tools that allow us to correct any alteration that might exist in our genes . That's why we call them genetic editors because they are able to change the letters that come out of their usual sequence and incorporate the good ones. "
The technique is relatively recent and was used for the first time in 2013.
"It must be said that at the laboratory level it is an extraordinary tool that allows us to modify at will the genes that we let's study it and do it with efficiency we've never seen before. "
At the laboratory level, basic research, CRISPR is a "revolutionary tool" according to Montoliu
"But its therapeutic applications are another thing, which is what generates more discussion."
Risks
In the Wellcome Sanger Institute study many cells published with CRISPR underwent reorganizations with unwanted "deletions" and "insertions" of DNA, which may cause some key genes to be "enabled" or "disabled".
In experiments, I used CRISPR / Cas9 as a tool to study genetic activity, however, it became clear that something unexpected was happening , M ichael Kosicki one of the authors of the new study published in the journal Nature .
"This is the first systematic badysis of the unexpected effects caused by editing with CRISPR / Cas9 in therapeutically relevant cells and we discovered that the changes on the I & # 39; 39; DNA have been underestimated until now "explained another of the authors, Allan Bradley .
Detailed Study
Montoliu pointed out that the new study "is a work of Allan Bradley's laboratory that I personally know and who is a scientist who deserves my respect".
"They use two types of mouse cells and some human tumor cells they make short and glued editing examples and do not just report the results they wait, but they badyze each of the results that the cells offer, as rare and disparate as they can be. "[19659025] Bradley is according to the Spanish researcher of some studies in which" someone bothered to check each and every possible outcome of an editing experience ".
The conclusion they reach is that the use of these CRISPR tools eventually generates multiple changes from those desired, incorporating more "genetic noise, more alterations".
Montoliu ensures that this "is not so surprising" that apply CRISPR. "The surprising thing is that no study has been conducted so regularly."
Unwanted Alterations
The main problem according to Montoliu is that "all the precision that the CRISPR editing tools have is not the same.Repair systems that must act by the side to restore the physical continuity of the chromosome. "
" When we cut a wire, the DNA wire, the cell responds immediately by trying to rebademble the two ends that were cut "
The genome consists of four letters, G, A, T, and C.
"G is always C and A is always T. So what trying to do the cell in any possible way is d? to have Ace before Ts or G in front of Cs and as if it was a Velcro, a zipper, to try to join them and to hang them to be able to restore the wound and this scar and to keep the continuity of the chromosome. "
In this attempt to repair "30 or 40 times probably in one of them the cell repairs in the way we had planned. That's what we would like to have one hundred percent of the time, but only 3, 4 or 5% happens. "
" The remaining 95% of the time what happens is that the cell in its attempts
Very few patients
Montoliu explained to the BBC Mundo that there are currently very few patients who were treated [19659003] applying CRISPR and treating patients treated with an ex vivo strategy, in which the patient's cells are extracted, worked in the laboratory and then reinserted.
The researcher explains that there are at least two major groups of therapies that can be developed to try to avoid genes that have an altered sequence.
"We can introduce editing tools directly into the patient's body and this is not yet safe to do, which is called [194] 59009] in vivo therapy ] "
" Or we can extract cells from the patient, for example from their blood, and those cells outside the patient in the lab are edited and they incorporate the alteration that is intended that may have application therapeutic, then validate and verify and select the cells that can be reintegrated into the patient. "
This last technique has the advantage that allows to select the cells that were edited ] and [19659003] have exactly the expected modification and reject those who incorporated unforeseen mutations.
"Prudence"
Montoliu baderted that the Wellcome Sanger Institute's study is "a call for caution". " We must humbly badume our limits we do not control everything, what we can do is select the cells that were edited correctly and that or we can do it when the cells are out of the person. "
Therefore, until the level of accuracy of CRISPR tools in repair systems is achieved, great care must be taken in the use of the technique. , according to Montoliu, who agrees with the call to caution researchers in England.
"We all have family members, friends, we all know people with rare genetic diseases and we would like to have therapies"
However, "the responsible use of these technologies must be encouraged and we must transfer these potentials to the clinic when they are actually safe, "adds the Spanish scientist.
" Nobody will enter a surgery room with a 5% chance of success. the surgeon will tell you that you will have at least a 50% chance. "
Similarly, with respect to CRISPR," what we need to do is increase potential benefits and reduce risk " .
[ad_2]
Source link
