How to increase the yield of neurons

Polymer substrate increased the survival rate of neurons in the brain by 38 times

Ekaterina Rusakova, N+1

American scientists have developed a technology that allows to increase the growth and increase the survival rate of neurons grown from stem cells and injected into the brain of mice. The results of the study are published in Nature Communications (Carlson et al., Generation and transplantation of reprogrammed human neurons in the brain using 3D microtopographic scaffolds).

Amino acid-based biopolymers have been designed for biomedical research. Earlier, scientists found out that a three-dimensional substrate made of biopolymer fibers based on the amino acid tyrosine supports the growth, self-renewal and directed differentiation of human embryonic stem cells. In a biopolymer substrate, cells become less mobile, so the organization of the cell colony changes and the interaction between cells improves.

The authors differentiated human induced pluripotent stem cells into neuronal cells, while they grew cell cultures on three-dimensional substrates ("thick" and "thin") with different thicknesses of polymer fibers (3.2 and 1.25 micrometers, respectively) and different distances between them.

"The optimal pore size should be large enough to allow cells to develop inside the substrate, but small enough for mature neurons to "feel" the presence of neighboring cells and grow nerve processes, establishing contact between them. Such contact increases cell survival and allows them to mature into full–fledged neurons that are able to transmit an electrical signal throughout the growing neural network," explains (in a press release from Rutgers University Future Brain Therapies for Parkinson's Possible with Stem Cell Bioengineering Innovation) one of the authors of the study, professor of Rutgers University Prabhas Moghe (Prabhas Moghe).

According to the researchers' hypothesis, on a "thick" substrate, due to the penetration of cell culture deep into the substrate and better interaction of stem cells with each other, cell growth will be better and the percentage of mature neurons will be higher. While in a "thin" substrate, the distance between the fibers is too large and the cells will not be able to penetrate into the polymer tissue. As a control, the scientists used a two-dimensional biopolymer film.

As the scientists expected, more viable and mature neurons grew on the "thick" biopolymer substrate. 65 percent of cells grown on a "thick" three-dimensional substrate produced proteins necessary for the growth of nerve processes. For the "thin" substrate, the indicator was lower – 50 percent, and only 40 percent of the cells grown on the control substrate matured and were able to synthesize the proteins necessary for growth.

To find out how the grown neurons will take root in brain tissue, the authors of the study injected neurons on a polymer substrate and individual neurons grown as a cell culture into the striatum (brain department) of mice.

*The striatum is part of the structure of the terminal brain (the anterior part of the brain). It is so called because on the frontal and horizontal sections of the brain it looks like alternating bands of gray and white matter. The striated body regulates muscle tone, participates in the regulation of the work of internal organs, in the formation of conditioned reflexes. With the development of incurable Parkinson's disease, which is characterized by muscle rigidity, involuntary trembling (tremor) of the limbs and deterioration of motor activity, the motor neurons of the striatum die.

Three weeks after the injection, the scientists tested the survival of neurons. It turned out that 5.75 percent of neurons grown and injected into the brain together with a polymer substrate survived, which is 38 times higher than the survival rate (0.15 percent) of individual neurons.

The processes of human neurons (red) germinate through a polymer substrate.
Prabhas Moghe / Rutgers University

The researchers believe that the presented technology will allow to develop a method for the treatment of neurodegenerative diseases, in particular Parkinson's disease.

Portal "Eternal youth" http://vechnayamolodost.ru  21.03.2016