"Mini Brain" helps to treat a rare and incurable brain disease in childhood

The average life expectancy of children with WOREE syndrome is 40 months (about three years), according to a recently published review article, and currently there is no cure for this disease. The children will live in great suffering until they die. The research is based on technological breakthroughs of the last decade, which enable the study of human diseases in a personalized model for the patient

In 2014 Two neurological syndromes resulting from mutations in the WWOX gene were described for the first time - the first, a "milder" syndrome called Spinocerebellar ataxia type 12 (SCAR12 syndrome), and the second, a more "severe" syndrome called WWOX-related epileptic encephalopathy (WOREE syndrome). Both diseases appear in early childhood and are characterized, among other things, by severe developmental impairment, functional neurological disorders and seizures, while WOREE is also associated with premature death. The average life expectancy of children with WOREE syndrome is 40 months (about three years), according to a recently published review article, and currently there is no cure for this disease. The children will live in great suffering until they die. Very little is known about the mechanism and there is no effective treatment. Although it is a rare disease, at least eight cases of these syndromes have been described in Israel.

One of the world-renowned researchers for researching the WWOX gene is Prof. Rami Akilan, from the Lautenberg Center for Immunology and Cancer Research at the Israel-Canada Medical Research Institute (IMRIC) of the Faculty of Medicine at the Hebrew University, who began researching the gene for the first time in his post-doctorate, and even continued to deepen his scientific work in the laboratory he established at the university. During the period of his research, the gene gained a great reputation as part of a group of genes known as "tumor suppressor genes". Following his scientific publications, Prof. Akilan established himself as one of the greatest experts in the world for garden research. Therefore, after the discovery of the syndromes, parents of sick children from all over the world began to turn to him, some begging him to save their children from the serious illness. As a result, even though his field of expertise is cancer, Prof. Akilan decided to devote considerable efforts and resources to researching the neurological syndromes WOREE and SCAR12.

In a new multi-institutional study, led by Daniel Steinberg, a student in the MD-PhD track, and under the guidance of Prof. Akilan, published in the prestigious journal EMBO Molecular Medicine, the mystery behind the diseases is beginning to be revealed. The research is based on technological breakthroughs of the last decade, which enable the study of human diseases in a personalized model for the patient. First, blood samples were taken from patients with both types of syndromes, the white blood cells were produced, and through "reprogramming" technology, the cells were returned to a stem cell-like state, which is called induced pluripotent stem cells (iPSCs). These cells have the ability to differentiate into almost every cell in the body, thus effectively simulating the different types of cells in the patients' body. Secondly, these cells were grown in 3D so that they would differentiate into the cells that make up the brain - thus creating a "mini-organ" (or "mini-brain") in a plate in the laboratory, simulating the development of the brain of the human fetus and therefore called a "brain organoid" (Organoid = organ like ). "The method has recently been tried against a number of diseases, even for the study of the corona virus," explained Daniel Steinberg.

And by extension: the iPSCs are "seeded" in special plates that prevent them from sticking to the bottom of the plate, so they remain "floating" in the growth fluid (medium) and form a cluster of cells known as the Embryoid body, since, similar to embryonic development, it allows the stem cells to spontaneously differentiate into all types of cells in the body. After that, gradually and over the course of about 30 days, the medium in which the tumor grows is replaced with a medium that supports the differentiation of the cells into brain cells. That is, the cells are only "gently directed" in the direction of the brain cells, and then each cell randomly chooses to develop into whatever cell it chooses - something that allows for a rich variety of cells. About two weeks after the start of the experiment, the aggregates are embedded in a special material called Matrigel, which is a gel made of proteins that forms a kind of scaffolding that enables the aggregates to grow in three dimensions (3D) and create complex structures that simulate the development of the brain. After about 30 days, you can find many subtypes of cells representing different populations of cells and different areas in the brain, which is why it is called a "brain organoid". The organoid is grown while shaking, and thus it can actually be allowed to continue growing, developing and maturing for a year or even more. so in fact, uniform cell aggregate (stem cells, iPSCs) get the Targon "mini-organ" (*image below, page 3). Similar approaches are applied today to many organs - organs of the digestive system, kidneys, eyes, the reproductive system and more.

The next step was to investigate the newly created model, thus learning on the one hand the role of the WWOX gene in the development of the brain, and the effects of the changes (that is, the mutations) in it on the development of the disease. The researchers used electrophysiological methods, in which the electrical activity in neurons is measured, and molecular methods such as immunofluorescence and RNA sequencing, which enable the study of the different types of cells in the brain, changes in proteins and gene expression. This is how the researchers discovered that in the early stages of embryonic nervous system development, the WWOX gene is specifically active in the parent cells from which all brain cells are formed, but not in the adult cells. They also discovered that the loss of the gene causes overactivity of neurons in the brain, changes in the composition of the cells that make up the brain and molecular changes within the cell, such as damage to the cell's ability to repair damage to the cells' hereditary material, the DNA. "It should be noted that these changes were specific to the 'severe' disease (WOREE syndrome), a finding that emphasizes that the model makes it possible to distinguish between different epileptic diseases, and thus the approach can enable the study of additional neurological syndromes," explained Prof. Akilan.

Finally, the researchers tested the effect of returning the normal gene to the patient's cells, and discovered that this way it is actually possible to "repair" most of the vulnerabilities. Although this method is not yet ready for clinical use in patients, it opens a window for future research on the subject, and supports the idea that it is possible to help these patients with a gene therapy approach. "It should be emphasized that this is the first time that these diseases have been modeled using human samples from patients, and that this research helps pave the way for future studies to understand the molecular basis of diseases, and to develop new treatment strategies," explains Daniel Steinberg. 

for scientific publication

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