Gene editing will change the world faster than we think. CRISPR genome editor: a technology that will change medicine
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2017 once again demonstrated the enormous potential of genetic editing in medicine. For example, it could change transplantation. Increased qualifications of surgeons and new technologies make it possible to perform fantastic operations, but all these miracles remain in little demand due to the extremely low number of donor organs. Thus, in the UK, 15,000 patients require a heart transplant every year, but only 150 can receive it. The solution may be to use organs whose organs are used in such a way as not to cause negative consequences for the recipient. An equally pressing problem - the spread of antibiotic-resistant bacteria - can also be solved using CRISPR. Several teams of researchers are working to destroy such “superbugs” using .
Gene editing produces the first complete cure for HIV
Reports that CRISPR has been used to cure a particular disease are becoming commonplace. So, scientists managed to cure it, but so far only in mice. Skeptics are often dubious about results demonstrated in rodents, but even for them there is exciting news - such as how a boy suffering from a rare disease received a transplant. square meter. New skin, replacing 80% of the old, diseased skin, was grown from 3 sq. cm, which were exposed to the modified virus. Perhaps this year we will see companies that will put gene therapy on stream and begin to treat sickle cell anemia, thalassemia and others with its help. And, of course, CRISPR will continue to be used to fight cancer - for example, by modifying humans so that they are more effective at finding and destroying malignant tumors.
Scientists have finally accomplished with the help of gene editing what was considered science fiction until recently - they changed the genome directly. The method was used to treat Hunter's disease, a rare genetic disease associated with a lack of an important enzyme in the liver. Billions of copies of corrective genes and the tools necessary to implement them were introduced into the body of a 44-year-old man; V in this case it was not CRISPR, but the zinc finger method. The researchers took a risk, but the patient, who had undergone 26 operations, had no choice. If successful, scientists will conduct similar therapy for patients with hemophilia and phenylketonuria. Also last year, a viable human embryo was genetically modified for the first time using CRISPR, first in , and then in . In both cases, the embryo was spared several mutations responsible for hereditary diseases, but it was not allowed to develop for ethical reasons. However, the reality of American work is scientific opponents.
CRISPR as a weapon
Gene editing can also become a real weapon. Fortunately, there is no talk yet of using it against people - we mean pest animals, for example, mosquitoes. By themselves, these insects are overwhelmingly harmless, but they can carry various diseases - from yellow fever to malaria. These diseases cause billions of dollars in damage to the global economy and kill hundreds of thousands of people a year. Experts propose to edit the genome of mosquitoes so that they can no longer transmit pathogens. Another option is to exterminate them completely or significantly reduce the population by releasing sterile males. This approach is shared by DARPA, which has invested in “combat” CRISPR research. Environmentalists watch such initiatives with concern: the destruction of an entire species can destroy ecosystems, and the presence of technology that can exterminate populations in the hands of government or business poses a serious threat to the environment.
Bill Gates: “Cancer gene therapy will eradicate infectious diseases”
With much greater sympathy, experts look towards New Zealand, where they are planning with the help of CRISPR. Once upon a time there were no mammals in this country except pinnipeds and bats, but man brought rats, cats, stoats and possums here. Mammals quickly turned into pests, destroying the local fauna - primarily birds, which lived for millions of years in a world without predators. Many species are already extinct, and to preserve the remaining biodiversity, the New Zealand government is ready to take tough measures. According to the plan, by 2050 there should be no introduced animals left on the islands. Traditionally, poison and traps have been used to combat them, but creating a genetic system that independently spreads throughout the population and reduces reproductive success is much more effective and safer for native species. New Zealand scientists are currently studying whether genetic warfare will cause more harm than good.
The Monsanto company has long become synonymous in the public eye with the “evil corporation” from Hollywood films and scares many no less than a hypothetical “genetic weapon.” However, the goals she voices seem good: for example, the biotech giant plans to use CRISPR to develop crops that are more productive and resistant to extreme conditions environment. Perhaps this technology will help the warming Earth. The agriculture of the future will also use genetic modification of animals - for example, in China they have already created it by replacing some of their genes with the genes of mice.
Rivals and successors of CRISPR
For all its advantages, CRISPR is an imperfect technology. When cutting DNA and introducing the desired gene into the genome, errors are possible: for example, you can accidentally touch a neighboring gene or cause a mutation. The one proposed by experts from the Howard Hughes Medical Institute does not have these shortcomings. Instead of inserting and cutting entire pieces of DNA, they replace individual nucleotides in it, rewriting the “letters” that write the genome. CRISPR is often compared to scissors, in which case the new technology can be called a “pencil.” It is ideal for correcting single harmful mutations.
Another alternative, eukaryotic multiplex gene editing (eMAGE), would also allow the introduction of new genes. And researchers from the startup claim that they have learned to replace damaged parts of the genome with edited ones, using the natural mechanisms of cell division. According to them, they managed to make this process manageable with the help of special viruses. True, we should wait for strict scientific verification of the stated results. In many cases, instead of genetic modification, it is more effective to use the so-called. In this case, the RNA chain, enzyme and transcription activator are located at the desired gene and trigger its work. The gene does not need to be cut or pasted - simply restoring its function.
The first gene therapy drug entered the US market
Technologies
Perhaps the smartest thing to do is not abandon CRISPR, but improve it. For example, a virus that delivers RNA and an enzyme into the cell nucleus can be attacked by the immune system, which will reduce the effectiveness of the method. To avoid this, you can use . The technology was tested by MIT employees on mice and showed excellent efficiency: the necessary genes were edited in 80% of the cells. The technology can also be modified for other purposes. For example, deprive this tool of the ability to cut out pieces of DNA, leaving only the ability to attach to the right point genome. In this case, CRISPR would be an ideal tag indicating the location of mutations, which could then be viewed using an atomic force microscope. This will allow, for example, to identify those leading to various diseases. The method will be more effective than traditional sequencing and fluorescent hybridization.
Fears and doubts
Like any new technology, gene editing causes mistrust in society. Many of us are still afraid of eating GMO foods, so we shouldn't be surprised at the protests against tampering with human genetic code or wild animal populations. But while many fears can easily be attributed to biological illiteracy, ethicists have more serious objections. What if, having learned to edit the genome of embryos to combat genetic diseases, we begin to produce “designer” babies with a predetermined eye color and level of intelligence? Experts in the field of genetics consider these fears to be justified, but... Firstly, the genome does not determine 100% what we are - upbringing and the environment in which we develop play an equally important role. Secondly, two other technologies, the introduction of which were considered the first steps towards dystopias in the spirit of Gattaca, have shown their safety over the decades. It's about about IVF and amniocentesis (analysis of amniotic fluid and placental tissue). Most likely, the same will happen with CRISPR, although government control of its use will not hurt.
And it is already being implemented: for example, selling kits for genetic editing at home (which, apparently, are also completely useless). Those who want to play genetic engineer should do so under the supervision of a specialist, for example, in courses organized by a New York startup. For $100 a month, anyone can have access to the laboratory and everything necessary equipment. And for $400 you can take an intensive four-day course in CRISPR technology using yeast as an example. Although most participants come to the lab for fun, they take away with them knowledge about gene editing and ethical standards when working with him.
Infographics for the “bio/mol/text” competition: CRISPR/Cas is an adaptive immunity system in bacteria and archaea that is also useful for eukaryotes. We have tried to make clear this mechanism, which created an explosion in the biological community and likely greatly changed the future of science and humanity. In this infographic you will learn a short history studies, mechanism and possible applications of the CRISPR/Cas system.
"Bio/mol/text"-2016
This work earned the audience award at the “bio/mol/text” competition in 2016.
Only infographics participated in the competition!
The text was written by Olga Volkova.
The general sponsor of the competition, according to our crowdfunding, was an entrepreneur Konstantin Sinyushin, for which he has great human respect!
The sponsor of the audience award was the Atlas company.
The sponsor of the publication of this article is Dmitry Gennadievich Kalashnikov.
How does the immune system of prokaryotes work?
CRISPR-Cas systems are found in almost all known archaea and half of bacteria. More often they are located on the chromosome, less often - as part of phages (bacterial viruses) and other mobile genetic elements. These systems consist of two main blocks: CRISPR cassettes and adjacent to it gene cluster cas . A cassette is a block of direct almost palindromic (“mirror”, complementary sequences capable of folding into hairpins) repetitions 24–48 nucleotide pairs in size. These repetitions are interspersed spacers- unique inserts of approximately the same length. The spacers are identical to various regions of phages and other mobile elements that have ever entered this cell or its ancestors. Number of repetitions in different systems ah varies from units to hundreds.
Thus, CRISPR can be thought of as a collection of repeat-separated “photographs” of cell boundary invaders. This collection is compiled by simply borrowing their pieces, and in order to resist a new invasion of the same molecular agents, the collection must be regularly “reviewed” and updated. This function requires leader sequence, preceding a series of repetitions. It is rich in low-melting AT pairs and contains a promoter that controls the transcription of the CRISPR cassette (“collection browsing”).
Genes cas encode proteins that take on the brunt of the work of inserting spacers and destroying agents with identical sequences ( protospacers) and help process the CRISPR transcript: divide the photo garland into separate portraits. The destruction function is performed by Cas proteins called effector. Depending on the type of effectors, all CRISPR systems are divided into two classes: I class the target is destroyed by a multiprotein complex, and II- one large protein. These classes are further divided into six types. Most effectors attack DNA, only one attacks exclusively RNA, and rare ones attack both molecules. One organism can contain several different systems, and spacers differ in different cells even of the same population.
What this leads to can be learned from the competition article about bacteriophages and the eternal arms race in the phage and bacterial worlds: “ Bacteria Eaters: Killers as Saviors". By the way, there are many interesting copyright electronic images of phages.
For solutions engineering problems The type II system, which belongs to class II, is most suitable - it is the simplest. It is its effector protein that is called Cas9 - the same designation that appears in modern genome editing systems.
How is CRISPR-mediated immunity formed?
If a virus penetrates a bacterium or archaea equipped with a CRISPR system, it turns on adaptation function module systems: specific Cas proteins - in all systems these are at least Cas1 and Cas2 - cut out the fragments they like from the stranger. In some cases, an effector protein also helps to select a protospacer. Proteins select areas near a specific sequence PAM (protospacer adjacent motif) - only a few nucleotides, but different for different CRISPR systems. Then these same adaptation proteins insert the fragment into the CRISPR cassette, always on one side - at the leader sequence. This is how a new spacer is formed, and at the same time a new repeat. This whole process is called adaptation, or acquisition, but in essence this is remembering the enemy. Information about all remembered enemies is received during division by all the offspring of the cell.
How is CRISPR-mediated immunity implemented?
To search for re-invading agents, the CRISPR cassette must express. As a result of its transcription, a long RNA molecule is formed - pre-crRNA. With the help of RNase III and, as a rule, Cas proteins, the transcript is cut into repeats into individual crRNA- molecules containing one spacer and pieces of repeats surrounding it (one of them is longer). In type II systems, this process, called maturation, one more participant is needed - tracrRNA (trans-activating CRISPR RNA), which is encoded next to cas-cluster.
Next, in class I systems, crRNA interacts with the Cas protein complex, and in class II systems, crRNA or tracrRNA-crRNA duplexes bind to one effector protein, for example Cas9. This is how it is formed interference function module- a working immune unit consisting of a guide RNA and an effector protein (or complex). A set of such units “scans” the cell in search of invaders.
When a complementary crRNA sequence, that is, a protospacer, is detected, the module “sticks” to it and determines whether it is marked as “self”, cellular. If not, and if the same PAM is adjacent to it, then the effector protein, which is an endonuclease, cuts both DNA strands in strictly defined places. The whole process is called interference. In a special case, in a type VI system, there is RNA interference, because the effector protein is a ribonuclease and destroys RNA. One way or another, the attacked phages or plasmids are disabled. Well, this creates an extra opportunity to “steal” new spacers.
What problems may arise during the implementation of the immune response? It is possible that with distance from the leader sequence, that is, from the CRISPR promoter, the chances of the spacer to be transcribed and mature decrease. In addition, there is an opinion that over time, remote spacers can accumulate mutations that prevent effective interference with the target, or are completely removed. But since the adaptation of new spacers occurs near the promoter, the distant spacers are photos of agents that have not attacked this cell line for a long time, and the cell does not need constant combat readiness in relation to them. Even single-nucleotide mutations of the target can become a real problem. In general, complementarity is paramount in this matter.
Shouldn't we tame someone else's immunity?
Having studied in detail the principles of operation of the streptococcal CRISPR-Cas9 system (type II), scientists thought: why not try to correct the genomes of other organisms with its help? New hopes have emerged for the treatment of genetic (and other) human diseases, because this method of editing in vivo could have been more effective than the nucleases ZFN and TALEN, which were already being extensively tested at that time.
Everything needed for new technology, is to place the Cas9 protein gene and a CRISPR cassette on the vectors, where the spacers are made identical to the places in the genome that need to be changed. By changing the number and type of spacers, several different regions of the genome can be modified at once. They quickly realized that tracrRNA and crRNA can be painlessly combined into one chimeric molecule sgRNA (single-guide RNA), and RNase III in eukaryotic cells is easily replaced by other ribonucleases. Well, it was also necessary to optimize the system for eukaryotic cells: correct the codon composition and add a nuclear “address” so that it clearly follows the place of work - the chromosomes.
The result was a simple and, importantly, cheap two-component system: gene cas9 and the CRISPR cassette are transcribed in the cell nucleus of the selected organism, the CRISPR transcript is cut into individual sgRNAs, which combine with Cas9 proteins and search for a target. When sgRNA finds a complementary site in the genome of an organism, Cas9 cuts both DNA strands bluntly. That's it, the work of the CRISPR system is over. Now the baton is passed to the repair systems of the body itself. They decide how best to patch up the cut: whether to simply sew the pieces together (this will be a non-homologous joining of the ends, NHEJ), or, if there is a suitable template with flanks complementary to the DNA sections on both sides of the break, put a “patch” (this will be homologous recombination). So, the first option is beneficial if you need to cut something out, the second - if you need to insert something or replace a defective DNA section with a normal one, which is simply introduced on a suitable vector. Sometimes homology with a paired chromosome is used if the desired locus on it is not defective.
Of course, the technology is not without its drawbacks. Cas9, for example, can exhibit off-target activity by turning a blind eye to minor mismatches between the sgRNA and the target. According to K. Severinov, the main problem is bioinformatic prediction of targets, since, in addition to the presence of a PAM region, it is necessary to take into account a lot of factors, including the state of chromatin. In addition, the scenario in which the cut will be repaired does not always correspond to the desired one, so factors that influence the choice of this scenario by the cell are now being actively sought. In addition to optimizing CRISPR-Cas9 and the mechanisms for its delivery to the desired cells, other types of CRISPR systems are being tested.
Range of applications of CRISPR-Cas9 and its modifications
The application points of CRISPR technology can be conditionally grouped into three large groups: “CRISPR for research,” “CRISPR for biotechnology,” and “CRISPR for therapy.”
1. "CRISPR - for research". The technology makes it possible to study the role of specific genes in the processes of development and life of organisms. An alternative is to establish the role of genes and their rearrangements in the occurrence and progression of genetic diseases and cancer: this tool allows you to create beautiful model systems.
If Cas9 is deprived of one nuclease domain, the protein becomes a nickase ( nCas9) - cuts only one strand of DNA, - and if two are deprived at once, then the protein becomes inactivated, or “dead” ( dead, dCas9). Such a protein does not cut anything, but the CRISPR-dCas9 system can be used to repress entire sets of genes or as a platform for constructing more complex regulatory and modifying complexes. For example, if an activating domain is attached to it, the expression of target genes is activated. For epigenetic modification required zones it is enough to add a modifying domain. And by tagging dCas9 with fluorescent proteins, different regions of chromosomes can be visualized. It is clear that the regulatory capabilities of the system will also be in demand in medicine. In addition, different CRISPR-Cas variants open up new opportunities for screening drug targets.
2. “CRISPR - for biotechnology”. Here we are talking about the use of CRISPR-Cas9 for at least three purposes:
3. “CRISPR - for therapy”. There seem to be no limits to imagination here. If we talk about hereditary diseases, CRISPR-Cas9 has already been “tried on” in cell cultures or animal models for sickle cell anemia and β-thalassemia, M2DS syndrome and Duchenne muscular dystrophy, cystic fibrosis (corrected mutant CFTR locus in human intestinal stem cells) and tyrosinemia , cataracts (a dominant mutation in the gene was eliminated in mice Crygc) and retinitis pigmentosa. In general, eye diseases are now in the spotlight because genetic constructs are easy to deliver to the eyes.
The advantages of genome correction in the germ line (as a set of any generative cells that connect generations of organisms with each other) and stem cells are obvious, but even changes made to the somatic cells of already developed organs have an effect. Especially when it comes to fighting liver and muscle diseases. On the results of therapeutic use of CRISPR-Cas9 in different types cells tells a fresh review.
A separate promising area is the fight against chronic viral diseases such as hepatitis and HIV infection. If the pathogen persists in the body as a provirus (viral DNA embedded in the cellular genome), then it can simply be cut out. This is exactly what a team of biologists from the USA did, ridding human lymphocytes of HIV (two “biomolecular” articles reported this at once: “ Battle of the Century: CRISPR VS HIV" And " CRISPR/Cas9 as an assistant in the fight against HIV"). True, HIV is an extremely changeable object, and we still have to break spears with it.
One can dream that variants of the recently described type VI CRISPR system, the one that destroys only RNA, will find application in tumor therapy, and, as it turns out, any cellular RNA indiscriminately: launching such a system into a cancer cell is like sending a curse on it.
CRISPR-Cas is more than just immunity
It turns out that this system means much more for bacteria and their evolution.
Non-canonical activities of CRISPR systems or their individual components arose as by-products of their immune function or as independently selected traits. Most likely, CRISPR cassettes and Cas proteins once worked separately, with the latter's original task being to regulate gene expression and DNA repair. Modern CRISPR-Cas components spotted:
The infographic was made jointly with Pavel Chirkov, Master of the Faculty of Political Science of St. Petersburg University state university. You can download it in one file.
Literature
- J. A. Doudna, E. Charpentier. (2014). The new frontier of genome engineering with CRISPR-Cas9. Science. 346 , 1258096-1258096;
- Ruud. Jansen, Jan. D. A. van Embden, Wim. Gaastra, Leo. M. Schools. (2002).
This text is one of them. CRISPR-Cas9 technology is attracting a lot of attention from both scientists and those interested in biotechnology. Many people believe that new method Precise gene editing will make it possible to create a perfect person in the future. Lenta.ru talks about what the CRISPR system is and whether we should expect miracles from it.
In early February 2016, it became known that the UK government allowed scientists to change the DNA of human embryos for research purposes using the CRISPR system. We are not talking about creating GMO humans, since all modified embryos obtained through in vitro fertilization will be destroyed after 14 days. However, the public became very concerned. For example, US Director of National Intelligence James Clapper said that genome editing technologies are potentially weapons of mass destruction. His pessimistic forecast was embodied in the new season of the series “ Secret materials", where the CRISPR system was used for global genocide. What is CRISPR technology, why does it cause so much excitement among scientists, fears among the public, and what can it really give to humanity?
Image: Steve Dixon/Feng Zhang/MIT
Antivirus protection
CRISPR is an immune system of bacteria and archaea that saves microorganisms from viruses. It was first discovered by Japanese scientists in the late 1980s in the bacterium Escherichia coli (Escherichia coli). They noticed that the bacterial genome contains repeating sequences separated by spacers - unique regions. However, what role all this plays, they could not find out then. A similar genetic cassette structure was later found in another microorganism - the archaea Haloferax mediterranei, and then in many other prokaryotes. Such regions began to be called the acronym CRISPR, that is, Clustered Regularly Interspaced Short Palindromic Repeats. In Russian - “short palindromic repeats, regularly arranged in groups.”
More than ten years later, geneticists discovered that next to the CRISPR cassettes are genes that encode proteins called Cas. Known spacers were compared with DNA sequences from extensive genomic databases. It turned out that the spacers are very similar to sections of the genomes of bacteriophage viruses, as well as plasmids - circular DNA molecules commonly found in bacteria.
A group of bioinformaticians led by Evgeniy Kunin from the National Center for Biotechnology Information proposed a mechanism for the operation of CRISPR cassettes and the Cas proteins associated with them. A virus that has entered a bacterial cell is detected by a complex of Cas proteins carrying with them a spacer sequence. If the latter matches a section of the virus’s DNA (protospacer), then Cas proteins cut the foreign DNA, preventing infection. Later, scientists were able to insert a spacer with a fragment of the bacteriophage genome into a bacterial CRISPR cassette and observed how the microorganism successfully dealt with the virus. This served as one of the proofs of the proposed hypothesis.
Spacers in CRISPR cassettes are a template for the production of crRNA, which is sent together with Cas proteins to attack the virus. Where do spacers come from? When a bacterium encounters an unknown virus, it begins to cut out various sections of DNA from its own and someone else's genome and inserts them into the cassette. Of course, most of these pieces turn out to be useless and even harmful, but the one that helps the body fight the infection remains in CRISPR and is passed on to the descendants of the bacterium.
Image: Annual Review of Genetics
Penetrating the holy of holies
It turned out that there are several varieties of the CRISPR-Cas system. One of them encodes not a complex of Cas proteins, but only one - Cas9. This is a universal molecule that performs several functions at once: it binds foreign DNA and cuts it. It was in the system with the Cas9 protein that scientists saw an accurate genome editing tool. In a paper published in the journal Science in 2012, Emmanuelle Charpentier and Jennifer Doudna proposed artificial sequences as crRNAs that would recognize specific sections of DNA. Cas9 would then make the cuts where scientists need them. Other research group Around the same time, she showed that the CRISPR-Cas9 system can work with genomes not only in bacteria, but also in the cells of other organisms, including humans.
And before the CRISPR system, methods of genome editing were known. For example, using nucleases containing zinc fingers. These are artificial enzymes that do not exist in nature and are capable of splitting a DNA chain. The zinc finger is a special protein module containing one or more zinc ions. It is with the help of such structures that enzymes interact with DNA, RNA and other molecules. The scientists connected the zinc finger to another module that cuts the DNA strand. Such nucleases can be targeted to specific regions of the genome, where they make cuts. The problem is that for each site where a gap needs to be introduced, a specific protein must be synthesized, isolated and tested. In addition, the use of nucleases is associated with a high probability of errors: breaks often occurred in the wrong places.
The CRISPR-Cas system is much more convenient. The cut function is taken over by the Cas9 protein, which is the same for all target loci. All that needs to be done is to synthesize crRNA, which will tell the protein exactly where to introduce the double-strand break. Once the break is made, DNA repair systems are activated. Firstly, this is the mechanism of non-homologous end joining (NHEJ), which results in various mutations that disrupt gene functions. If you make many such breaks, you can achieve rearrangement of a large section of DNA.
Secondly, homologous recombination (HR), when similar or identical sections of DNA exchange nucleotide sequences with each other. This mechanism is used to repair damage to the double strand called double-strand breaks.
When it comes to controlled DNA editing, scientists are more comfortable with homologous recombination. Using the CRISPR-Cas system, breaks can be introduced so as to remove an entire section of DNA. In this case, geneticists slip in a sequence they created, which is inserted in place of the deleted one. In this way, it is possible to “repair” mutations that cause severe diseases. Scientists remove the defective section of the gene and replace it with a normal one. Moreover, it is possible to introduce new mutations, create different variants of the same gene, and add specific sequences to it, which affects the functions of the protein it encodes.
You can correct many defective genes at once. To do this, you only need to synthesize the corresponding crRNAs, whose sequences coincide with the necessary areas DNA. Cas9 proteins bind to crRNA and rush to “repair” genes. It should be clarified that when we talk about coincidence, we mean complementary correspondence. The principle of complementarity shows in which case bonds will be formed between different chains of DNA or RNA. Nucleotide A binds to nucleotide T, and nucleotide C binds to G. Therefore, for example, the ACTG fragment coincides with TGAC.
Image: Nature
Weapons against diseases
When it became clear that the CRISPR system could be used to edit the human genome, many laboratories around the world began active research. For example, they use technology to create genetically modified organisms. One of the directions is the creation of lactic acid bacteria that could resist the attack of bacteriophages that destroy cultures of beneficial microorganisms. But perhaps one of the most interesting applications of CRISPR is in the fight against retroviral infections.
Retroviruses - such as HIV - insert their genome directly into the DNA of an infected cell. A paper published in the journal Scientific Reports demonstrates how CRISPR-Cas9 can be used to purify HIV-infected T cells and even prevent the virus from re-embedding. Geneticists simply introduced genes encoding crRNA and Cas9 into the T-cell culture, which, in turn, successfully excised the viral DNA from the lymphocyte genome.
Chinese scientists carried out experiments on human embryos even before such research was allowed in the UK. In April 2016, geneticists reported that they had altered the genes of embryos to make them immune to HIV. Using CRISPR, they introduced a gene that is found in people who are immune to infection.
The CRISPR system has also come in handy in the fight against cancer. For example, work published in Nature Biotechnology shows that using a modified Cas9 protein, it is possible to turn off certain genes and thereby determine their role in the degeneration of normal cells into malignant ones. If it turns out that a mutation in a certain gene contributes to the development of cancer, then the next step is to correct the defect using genetic manipulation.
CRISPR can help treat blood cancer - leukemia. Instead of looking for a bone marrow donor, you can take tissue samples from the patient's own hematopoietic organ, correct the defective stem cells, ridding them of the fatal mutation, and then transplant them back. If the malignant cells remaining in the diseased body are destroyed by radiation, the corrected cells will be able to multiply and produce healthy blood cells.
Pandora's Box
Is the CRISPR system dangerous? At the current level of development, no. The concerns are largely related to the fact that it is still too early to edit the human genome for the purpose of treating hereditary diseases. The technology is still raw. Thus, the work of Chinese scientists was criticized for the large number of DNA breaks that occurred in the wrong place. In addition, only a few of the fifty embryos had the correct replacement of the gene section.
If genome editing technology saves humanity from hereditary diseases, cancer, viruses, then this is a matter of the future, which is perhaps much further away than optimists think. As for creating enhanced humans and the ethical issues involved, this is generally beyond what the CRISPR system is capable of.
With the help of CRISPR, a huge breakthrough is happening right now in genetic engineering: scientists plan to soon learn how to rid us forever of any diseases, with the prospect of any controlled mutations and eternal life.
We were prompted to publish this post by the video “CRISPR: gene editing will change everything forever,” which talks about the cutting edge of science in terms of genetic modification of humans: it’s not just about getting rid of diseases like AIDS, cancer and many others, but also about creating a flawless new species of people, people with superpowers and immortality. And this is happening right now before our eyes.
All these prospects are opening up thanks to the recent revolutionary discovery of protein CRISPR–Cas9, but first things first.
Previously, it was believed that the DNA in each of our cells is absolutely identical and contains our exact and unchanging copy - no matter what cell you take, but it turned out that this is not so: the DNA in different cells is slightly different and they change depending on different circumstances.
The discovery of the CRISPR-Cas9 protein was helped by observations of bacteria that survived a virus attack.
The oldest war on earth
Bacteria and viruses have been competing since the beginning of life: bacteriophage viruses prey on bacteria. In the ocean they kill 40% of total number bacteria every day. The virus does this by inserting its genetic code into a bacterium and using it as a factory.
Bacteria try unsuccessfully to resist, but in most cases their defense mechanisms are too weak. But sometimes the bacteria survive. Then they can activate their most effective antiviral system. They store part of the virus's DNA in their genetic code, the “CRISPR” DNA archive.Here it is stored until required.
When the virus attacks again, the bacterium creates an RNA copy from the DNA archive and
charges a secret weapon - the Cas9 protein. This protein scans the bacterium for viral interference by comparing each piece of DNA it finds to the archive. When a 100% match is found, it is activated and cuts off the DNA of the virus, rendering it useless, thus protecting the bacterium.
The Cas9 protein scans the cell's DNA for virus entry and replaces the damaged part with a healthy fragment.
Tellingly, Cas9 is very precise, like a DNA surgeon. The revolution came when scientists realized that the CRISPR system was programmable—they could simply give a copy of the DNA that needed to be changed and place the system in a living cell.
Besides being precise, cheap and easy to use, CRISPR allows you to turn genes on and off in living cells and study specific DNA sequences.
This method also works with any cells, microorganisms, plants, animals or people.
Scientists have found that Cas9 can be programmed to make any substitutions in any part of DNA - and this opens up almost limitless possibilities for humanity.
Is there an end to diseases?
In 2015, scientists used CRISPR to remove the HIV virus from patient cells.
and proved that it is possible. A year later, they conducted a more ambitious experiment with rats with the HIV virus in almost all of their cells.
Scientists simply injected CRISPR into their tails and were able to remove more than 50% of the virus from cells throughout the body. Perhaps in a few decades, CRISPR will help get rid of HIV and other retroviruses - viruses that hide inside human DNA, like herpes. Perhaps CRISPR can defeat our worst enemy, cancer.
Cancer is the result of cells that refuse to die and continue to divide, while hiding from the immune system. CRISPR gives us a way to edit our immune cells and make them better cancer hunters.
Perhaps, someday, cancer treatment will be just a couple of shots with a few thousand of your own cells created in a laboratory to cure you forever.
Perhaps after some time the question of cancer treatment is a matter of a couple of injections of modified cells.
The first clinical trial of such therapy on human patients was approved in early 2016 in the United States. Less than a month later, Chinese scientists announced that they would treat lung cancer patients with immune cells modified using the same technology in August 2016. The case is quickly gaining momentum.
And then there are genetic diseases, thousands of them. They range from mildly annoying to extremely fatal or causing years of suffering. With powerful tools like CRISPR, we may one day be able to do away with this.
More than 3,000 genetic diseases are caused by a single change in DNA.
We are already creating a modified version of Cas9 that corrects such errors and rids the cell of the disease. In a couple of decades, we may be able to eliminate thousands of diseases forever. However, all of these medical applications have one drawback - they are limited to one patient and will die with him if we do not use them on reproductive cells or in the early stages of fetal development.
CRISPR will likely be used much more widely. For example, to create a modified human, an engineered child. This will bring smooth but irreversible changes in the human gene pool.
Engineered Children
Means of altering the DNA of a human fetus already exist.
but the technology is at an early stage of development. However, it has already been used twice. In 2015 and 2016, experiments by Chinese scientists with human embryos achieved partial success on the second attempt.
They have revealed enormous difficulties in editing the genes of embryos, but many scientists are already working to solve these problems. It's the same as computers in the 70s: they will get better in the future.
Regardless of your views on genetic engineering, it will affect everyone. Modified humans can change the genome of our entire species, because their grafted qualities will be passed on to their children, and will slowly spread through generations, slowly changing the gene pool of humanity. It will start gradually.
The first designed children will not be much different from us. Most likely, their genes will be changed to get rid of fatal hereditary diseases.
As technology develops, everything more people will begin to think that not using genetic modification is unethical because it dooms children
to preventable suffering and death.
As soon as the first such child is born, a door will open that can no longer be closed. At first, some traits will not be touched, but as acceptance of the technology and our knowledge of the genetic code increases, so will the temptation.
If you make your offspring immune to Alzheimer's disease, why not in addition not give them improved metabolism? Why not reward them with excellent vision? How about height or muscle? Lush hair? How about the gift of exceptional intelligence for your child?
Enormous changes will come as a result of the accumulation of personal decisions of millions of people.
It's a slippery slope, and modified humans may become the new normal. As genetic engineering becomes more commonplace and our knowledge improves, we may be closer to eradicating main reason mortality - aging.
2/3 of the approximately 150,000 people who die today died from causes related to aging.
Today it is believed that aging is caused by the accumulation of damage in our cells
such as DNA breaks or deterioration of the systems responsible for repairing these damages.
But there are also genes that directly affect our aging.
Genetic engineering and other therapies could stop or slow down aging. It may even be possible to reverse it.
A typical reaction to the possibility of eternal life (like any other technology that is familiar now, but revolutionary several hundred years ago).
Eternal life and “X-Men”
We know that in nature there are animals that do not age. Maybe we could borrow a couple of genes from them. Some scientists believe that one day aging will be eradicated. We will still die, but not in a hospital at 90 years old, but after a couple of thousand years spent surrounded by our loved ones.
The challenge is enormous and the goal may be unattainable, but it is conceivable that people alive today may be the first to taste the benefits of anti-aging therapy. It may just be a matter of convincing a smart billionaire to help solve this big problem.
If we look at this more broadly, we could solve many problems with the help of specially modified people, for example, who could cope better with high-calorie foods, and get rid of such ailments of civilization as obesity.
Having a modified immune system with a list of potential threats,
we could become immune to most of the diseases plaguing us today. Later still, we could create humans for long-term space travel and to adapt to different conditions on other planets, which would be extremely useful for maintaining our life in a hostile universe.
A few pinches of salt
There are several major obstacles, technological and ethical. Many will feel fear of a world where we weed out imperfect people and select offspring based on what is considered healthy.
But we already live in such a world. Testing for dozens of genetic diseases or complications has become the norm for pregnant women in many countries. Often, one suspicion of a genetic defect can lead to termination of pregnancy.
Take for example Down syndrome, one of the most common genetic defects: in Europe, about 90% of pregnancies with an established presence of this disorder are terminated.
Genetic selection in action: Down syndrome is already diagnosed at an early stage of embryo development and 90% of pregnancies with this diagnosis are terminated.
The decision to terminate a pregnancy is a very personal one, but it is important to understand that we already select people today based on health status. There is no point in pretending that this will change, so we need to act carefully and ethically, despite the increasing freedom of choice thanks to further developments in technology.
However, all these are prospects for the distant future. Despite the power of CRISPR, the method is not without its drawbacks. Editing errors can happen, and unknown errors can occur in any part of the DNA and go undetected.
A gene change can reach desired result and cure the disease, but at the same time provoke unwanted changes. We simply don't know enough about the complex relationships of our genes to avoid unpredictable consequences.
Work on precision and observation methods is important in upcoming clinical trials. And while we've discussed a possible brighter future, it's also worth mentioning a darker vision. Imagine what a country like North Korea what to do with this level of technology?
It is important that genetic modification technology does not fall into the hands of totalitarian regimes, which could hypothetically use it to harm humanity - for example, create an army of genetically modified soldiers.
Can she extend her reign forever through forced engineering?What will stop a totalitarian regime from creating an army of modified super soldiers?
After all, this is theoretically possible. Scenarios like this lie in the distant future, if they are possible at all, but proof of concept for such engineering already exists. Technology really is that powerful.
This might be a reason to ban engineering and related research, but that would certainly be a mistake. Banning human genetic engineering will only lead science into areas with rules and laws that we would not be comfortable with. Only by participating in the process can we be confident that research is being conducted with care, intelligence, control and transparency.
We can research and introduce any genetic modifications into humans.
Conclusion
Feeling anxious? Almost all of us have some kind of imperfection. Would we be allowed to exist in such a new world? The technology is somewhat frightening, but we have something to gain, and genetic engineering may be the next step in the evolution of intelligent species of life.
Perhaps we will end disease, increase life expectancy by centuries, and travel to the stars. You shouldn’t think small when talking about such a topic. Whatever your opinion on genetic engineering, the future is coming no matter what.
What used to be science fiction, will soon become our new reality.
A reality full of opportunities and obstacles.
You can also watch the video itself:
If you had the opportunity to destroy cancer, would you do it? Rid the world of HIV infection or eradicate the mosquito species that carries the Zika virus? CRISPR, a new gene editing technique that allows scientists to cut out unwanted pieces of DNA with surgical precision, can do this. And it is this technology that can radically change our familiar world in the very near future.
Today we will talk about CRISPR. This gene editing technology can not only significantly advance the field of medicine, but also save us from the known problems of food supply. The possibilities and potential of CRISPR seem endless, so we decided to combine the most interesting of them in one material.
What is CRISPR
CRISPR(also known as "CRISPR-Cas9") - unique instrument for genome editing. Allows geneticists and medical researchers to edit parts of the genome by removing, adding, or changing sequential sections of DNA. Moreover, CRISPR is faster, cheaper and more accurate than all previous known methods DNA editing and has a wide range of potential applications.At the moment, CRISPR technology is the simplest, most versatile and accurate method of genetic manipulation. The world of science is shocked by the sheer potential of CRISPR, and this is not exaggerated at all.
How it works?
The CRISPR-Cas9 system consists of two key molecules that introduce a change (mutation) into DNA. This:
- An enzyme called "Cas9". This CRISPR molecule acts like a pair of “molecular scissors.” Cas9 can cut strands of DNA at a specific location in the genome so that DNA fragments can then be added or removed.
- Part of RNA called "gRNA" (guide RNA). gRNA consists of a small piece of predesigned RNA sequence (about 20 bases long) located within a longer stretch of DNA. This region binds to DNA and RNA to “direct” Cas9 to the right side of the genome.
Strengthening food culture
CRISPR technology methods allow scientists to forever forget about GMO products and weak food crops that are prone to errors and various diseases. Using CRISPR, you can take the food industry to the next level new level- increase production while simultaneously removing triphosphates from products (a food stabilizer recognized as harmful to human health). In this case, there is also no need to use harmful pesticides - drugs for controlling plant pests.
Ministry Agriculture The US has reacted negatively to CRISPR-edited products. Residents, meanwhile, stood up to protect their crops and spoke out against genetically modified foods. However, CRISPR products are not GMOs. Using this technology, it is possible to remove potentially dangerous genes and make products healthy, high quality and durable.
Destroying cancer
Human gene editing using CRISPR is still very controversial. However, this technology could improve cancer immunotherapy and even cut out genes that cause cancer cells before they cause fatal damage to the human body.
In 2016, the National Institutes of Health began a study to eradicate three various types cancer in humans through CRISPR gene editing technology. The project received the support of Internet billionaire Sean Parker and was led by experienced scientists from the University of Pennsylvania.
The results of the study will not be known soon, since the project is still awaiting approval from the FDA. food products and medications).
Getting rid of mosquitoes with the Zika virus
Scientists have already realized the possibility of eradicating Aedes Aegypti (yellow fever) mosquitoes, which can spread the Zika virus. CRISPR technology can destroy an entire species in one generation.
Although CRISPR could eradicate harmful mosquitoes right now, the idea is controversial. There is a single, but very significant argument against the use of genome editing for mosquitoes - the creation of an unforeseen environmental disaster. Humanity does not yet fully understand the role mosquitoes play in the environment, so simply eliminating them as a species cannot be done. Otherwise, the consequences are inevitable, and the worst thing is that no one knows what will happen.
The second possible scenario is that using CRISPR could lead to an error and inadvertently create a new, improved species of super-mosquito. For example, they will be completely immune to modern technologies. Or the defective DNA could somehow pass on to other insects and, again, cause an environmental disaster.
Cures for all diseases
The potential of CRISPR technology could lead to the creation of improved drugs with the ability to modify cells in the body. An approximate representation of the capabilities of such drugs is the treatment of almost all diseases, simple and complex, rare and inherited.
Last year, Bayer struck a deal with CRISPR Therapeutics, a startup from the team of innovators who discovered Emmanuelle Charpentiere's Cas9 technology to create drugs using the technology. Soon other pharmaceutical companies emerged, opening the door to the creation of highly effective drugs.
As a result, CRISPR may well revolutionize the pharmaceutical industry.
Healing the Blind
Late last fall, scientists published the first study using CRISPR to cure blindness. A gene editing tool was used on rats to replace bad genetics that cause blindness with a working set of healthy genes.
A study conducted at the Salk Institute in California led to partial restoration of vision.
Also in another study, which was conducted by Columbia and Iowa universities in early 2016, scientists were able to show that it is possible to successfully treat a person with a congenital genetic defect of vision using CRISPR technology.
Thus, through genome editing, a person’s vision can be restored. In reality, this sounds like a miracle, but it is more than possible.
Elimination of HIV infection
Currently, people with fatal HIV infection are treated with a toxic cocktail of antiretroviral drugs. They suppress the virus, thereby preventing it from replicating itself and turning into full-blown AIDS. CRISPR can, as proven by a recent study that we wrote about on Trashbox.
A study using mice showed that CRISPR could be programmed to kill anyone in a host with incredible precision. We are also talking about the possible removal of primary HIV-1 DNA from the body. Ultimately, cutting out the entire DNA of a virus can stop it from spreading.
The next step in the research will be to repeat the process on primates, followed by human trials. People of the future will be able to live without the fear of acquiring immunodeficiency.
Removing genetic diseases before birth
Last week, scientists at Oregon Health and Science University published a paper outlining a way to successfully use CRISPR to eradicate a genetically inherited heart mutation in human embryos. Simply put, an unborn child can be born without inherited diseases.
The embryos were allowed to grow for several days, but the technology gave positive results. This was the first time scientists used CRISPR on human embryos. At the same time, scientists were able to demonstrate for the first time that genome editing technology could produce healthy embryos.
Imagine a world where people are born without disease. CRISPR is the key to this future.