Lassa fever outbreak

Would CRISPR be a hope for eradicating epidemic infectious diseases?

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Their names are scary, and rightly so, because these viruses are wreaking havoc. Ebola, Zika, Dengue, Lassa, ... cause hundreds of deaths and pose a major epidemiological risk. A new hope to stop these scourges comes from the famous molecular tool CRISPR. Often criticized for its sometimes unethical applications, it could save hundreds of lives in the case of infectious disease epidemics. Experiments are currently going well and are very promising, but they may soon come up against two obstacles: market stakes and the patent war.
 
Mast Tuesday, Nigeria declared the state of the epidemic. The virus Lassa has reportedly been detected in the country; ten to twenty thousand cases are detected every year in West Africa. A particularly formidable virus that triggers devastating fevers and kills in 20 to 40 % of cases. Slightly less than Ebola, but of proven dangerousness, this virus spreads at the epidemic stage by rodents. At present, there is no effective treatment available.
 
The whole problem lies in the diagnosis, which must be as early as possible in order to curb the disease and its epidemic spread. This is where researchers are announcing news that could be very positive. They have succeeded in developing a new, very simple, effective and cheap diagnostic test based on CRISPR technology.
 

CRISPR at the service of infectious disease screening

CRISPR is often referred to as a warning of the dangers posed by certain applications of these extraordinary genetic scissors. The most recent scandal to date is the one caused by a Chinese researcher who, alone, in the back of his lab, managed to give birth to twins genetically modified to resist HIV.

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CRISPR has the ability to be programmed to search for specific genetic fragments. In this case, the molecular tool has been programmed to locate fragments of RNA of the virus. Lassa. If successful, the approach could help detect a wide range of viral infections early so that treatments can be more effective and health workers can stop the spread of infection. A robust and user-friendly test could reduce mortality rates from Lassa explained in the magazine Nature Jessica Uwanibe, a molecular biologist who is developing a diagnostic Lassa at Redeemer University in Ede, Nigeria. « I'm working on something that could save a lot of lives. "
 
Scientists in Honduras and California are already testing CRISPR diagnostics for dengue fever, Zika viruses and cancer-associated strains of human papillomavirus (HPV). Even more recently, a study to explore a CRISPR test for the Ebola virus is underway in the Democratic Republic of Congo.
 
For most infectious diseases, diagnosis requires specialized expertise, sophisticated equipment and sufficient electricity - all of which are lacking in many places where diseases like Lassa are cracking down. CRISPR tests offer the interesting possibility to diagnose infections as accurately as conventional methods, and almost as simply as a home pregnancy test. And because CRISPR is designed to target specific gene sequences, the researchers hope to develop a technology-based tool that can be refined to identify the circulating virus strain within a week.
 
For Jennifer Doudna, a biochemist at the University of California at Berkeley and one of the historical inventors of CRISPR, together with her French colleague Emmanuelle Charpentier, "... we have to be able to make the most of our knowledge and experience. This is a very exciting direction for the CRISPR field. ".
 

A story of cutting

Nigerien doctors are conducting trials on a CRISPR diagnosis developed by researchers at the Broad Institute of MIT and Harvard in Cambridge. They have successfully coupled CRISPR with the Cas13 protein. Originally, CRISPR works with the Cas9 protein, but unlike the Cas9 protein, the enzyme used in the CRISPR-Cas13 tool cuts the gene sequence it has been asked to target. It then slices the RNA indiscriminately. In general, this behaviour is problematic when trying to edit genes; it is even a bias that CRISPR users are wary of. In this case, however, the indiscriminate cutting is a boon to diagnosis because any RNA fragment can be used as a signal.
 
It is on this characteristic that the Broad Institute team has developed a test, aptly named SHERLOCK. It detects RNA molecules that have been sliced by Cas13. The signal materializes as a dark band on a strip of paper. This signal is very similar to the one commonly used in pregnancy tests. When the signal registers, a fragment of RNA from the virus is present. Lassa. This technique provides results similar to those obtained by physicians using the conventional laboratory detection method known as polymerase chain reaction (PCR).
But compared to PCR, SHERLOCK costs half as much. In addition, it takes half the time to produce results. Finally, even though both test systems need electricity to operate, SHERLOCK runs on a simple car generator. This is a significant detail in countries where electricity is a scarce and very irregular commodity.
 
Jennifer Doudna and her team at Berkeley, with these hopes in mind, are working on other variants of the protein. Case to develop new tests, including one for cervical cancer screening. In fact, the entire CRISPR toolbox is being enriched with proteins designed to target certain types of diagnoses.
 
These are exciting innovations "says Dhamari Naidoo, technical officer at the World Health Organization, based in Nigeria. But she adds immediately that for these tests to be useful in low-income countries like those in Africa, researchers need to develop tools that are very inexpensive and available for licensing.
This is often where the problem lies. For example, a dozen diagnostic tests for the Ebola virus have been developed, but only two of them have been deployed for the current outbreak in the Democratic Republic of Congo. The rest have been delayed due to economic obstacles, including the lack of a large enough market for manufacturers to justify the costs of conducting and distributing the tests.
 

Fierce patent battle

CRISPR is no exception to this economic rule and for several years has been the subject of a patent ownership fair. A battle that reveals a not-so-glamorous side of science when accompanied by a very commercial potential.
 
On the one hand, the University of California at Berkeley was the first to file a patent application. On the other hand, the Broad Institute in Massachusetts applied to the U.S. Patent Office for an expedited process and was granted a patent before Berkeley.
On the one hand, Broad alleges that Berkeley's original application covers only the genetic manipulation of bacteria, not animals. On the other hand, Berkeley replies that it was self-evident that the technique could be used beyond bacteria and that "people of ordinary ability" would be able to use the technique on mice or humans, as evidenced by the teams of Jennifer Doudna and Emmanuelle Charpentier (University of Berkeley), George Church and Feng Zhang (Broad Institute), or Jin-Soo Kim (South Korea).
To which Broad replies that such highly specialized researchers do not fit the legal definition of a "person of ordinary ability.
 
To complicate matters, CRISPR-Cas9 - a "biological scalpel" that can be used to manipulate genes with great precision - already exists in nature; what researchers have developed in 2012 is a way to use it as they see fit. And that's saying something: since 2012, laboratories around the world have been experimenting with it on all kinds of genomes, and there are now reportedly several hundred patent applications filed for as many CRISPR-related applications.
 
The dispute before the judges of the United States Patent Office (USPTO) has been ongoing since January 2016 and another application has been filed before the European Patent Office. The game is close and some of the arguments take the judges very far from the science. Such resentment is unusual between two academic institutions, commented in Nature Mark Summerfield, an Australian patent lawyer. But he adds at the outset that behind these two universities there is a list of companies that pay the legal fees. « What's really behind it is the commercial interests... they're not going to get along, they're going to fight to the end..."
 
In light of the ongoing patent battles between Berkeley and Broad, CRISPR-based diagnosis of infectious diseases could be particularly problematic from an economic point of view. But Jennifer Doudna and Pardis Sabeti, who leads the SHERLOCK project at Broad, say they are committed to licensing their tools so that people who need them can use them. For Jessica Uwanibe, the Nigerian biologist working on the Lassa virus, that day cannot come soon enough. « I wish we could do this even faster. "she says. It's true that viruses don't wait for the outcome of the big financial battles around the green-carpet tables to decide to ravage people.
 
 

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