Source: McCarroll lab
A large group of US neuroscientists led experts from the Institute of Brody School of Medicine at Harvard University and Children's Hospital Boston have made an important discovery in the field of studying the mechanisms of schizophrenia. First time scientists have found a gene variant that is associated with the development of severe mental illness.
The discovery could lead to new drugs for
treatment of schizophrenia, which will affect the very cause of the disease. All
now existing therapies are able to deal only with the symptoms -
hallucinations, delusions, etc.
As the researchers found, lead to the development of schizophrenia gene mutation that
synthesis of proteins responsible for the so-called complement system 4 (C4). Known
These proteins are involved in the implementation of immune response in response to
invading foreign agents. Surprisingly, as demonstrated in his work
the authors, the same gene is responsible for the work and synaptic pruning -
"Weeding" in the brain of extra synapses. In particular schizophrenia
C4 variant gene causes that actively starts synaptic pruning
work. As a result, many synapses are destroyed indiscriminately, leading
to the development of the disease.
Synaptic pruning - it?
It is known that in the learning process in the brain form new synapses
- Such contacts or "nodules" between neurons through which chemically
the nerve impulse is transmitted.
In a mentally healthy people over a lifetime working mechanism that
trims excess synapses - a process called synaptic pruning.
If too little is cut extra synapses - it can lead as
Recent studies show that the development of, for example, autism. If
clipped too many synapses, as it turns out, it's too bad: excessive
"Crop" can lead to the development of schizophrenia.
How to look for the gene or looking for a needle in a haystack
«first learned about schizophrenia more than a hundred years ago, and yet, many
biological mechanisms of the disease remains unknown. Now,
When the human genome deciphered, it opens up entirely new possibilities for
studying the molecular and genetic mechanisms of its development ", - says a leading
study author Steven Makkeroll (Steven McCarroll).
In 2014, a group led by Makkerolla discovered more than a hundred sites
in the human genome, changes in which may be associated with the risk of
schizophrenia. But then it remained unclear which genes can be incorporated into
this process.
Then scientists began to study the genome of more than a hundred thousand people from 30
different countries. They received unexpected data: the analysis showed that the genes
associated with risk of schizophrenia, on the 6th chromosome. It is known that
Work of this chromosome is linked in many ways with the organization of the immune response
organism to infectious diseases. But again, the gene was not found.
Then, the authors have developed even a special technique. And, finally,
We discovered a gene responsible for the protein synthesis system compliment 4. This
gene explains Makkerroll, characterized by large variability: in different
people, it contains a different number of copies and various types. In the study of variations
this gene in mentally healthy people and schizophrenic patients, scientists and decided
to focus on. To do this, they studied its variations from the 65,000 people with
and without schizophrenia. And then we examined his work on the brain 700 dead
people.
As a result, they found that people with a particular variant of a gene,
encoding four proteins of complement system was significantly higher risk of developing
schizophrenia. But then came the question - why? What is the relationship between proteins,
responsible for the immune response and mental illness?
It may seem surprising, but the study showed that these same proteins
involved in the process of synaptic pruning. A special variant of the gene that
encodes these proteins leads to the fact that synaptic pruning activated
which leads to the "pruning" of many relevant synapses and the development of schizophrenia.
As the authors say, their discovery gives an answer to the question why patients
schizophrenia often cortex (her work is responsible for mental
activities) thinner than in healthy people: the thing is that they have fewer
synapses due to excessive "cutting».
Another important question that the discovery provides an answer why symptoms
Schizophrenia usually appear in adolescence: it is just in this
age in the brain is actively in the process of synaptic pruning.
«Of course, our study - is only the first step. While we are still very
far from the creation of new drugs for the treatment of schizophrenia. But we
very much hope that, based on our findings will one day be found
medicine, which will allow to properly configure and synaptic pruning
to save people from the risk of developing schizophrenia, "- says one of the authors
study known neuroscientist Stevens Beth (Beth Stevens).
On the results of his study authors
reported in the latest issue of the journal Nature .
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