The University of Luxembourg today revealed that researchers at its Luxembourg Centre for Systems Biomedicine (LCSB) have managed to grow the types of neurons affected by Parkinson's disease in a three-dimensional cell culture system.
LCSB scientists, working with Dr. Ronan Fleming of the research group Systems Biochemistry, have confidently reported that this system could greatly facilitate the continuing search for therapeutic agents in the future, as it provides a far more realistic model of the natural conditions in the brain compared with other systems currently available.The new 3-D cell system also represents a significantly cheaper alternative for use in the laboratory.
Parkinson’s disease is as of yet an incurable disorder of the central nervous system and is characterised in particular by the death of dopamine-producing neurons in the Substantia nigra of the midbrain. It is already possible to grow these dopaminergic neurons in cell cultures.
“But most such cell cultures are two-dimensional, with the cells growing along the base of a petri dish, for example,” explained Dr. Fleming, who led the group in its research. “Instead, we have the neurons grow in a gel that yields a far better model of their natural, three-dimensional environment.”
For the initial cultivation of the target neurons, the scientists used ordinary skin cells which were then converted through conventional methods into induced pluripotent stem cells (iPSCs). This process was developed by scientists Shinya Yamanaka and John Gurdon, who won the 2012 Nobel Prize in Physiology or Medicine for their efforts.
“By adding suitable growth factors, the iPSCs can then be converted in a second step into neural stem cells,” said Prof. Jens Schwamborn, head of the LCSB research group Developmental & Cellular Biology, which is responsible for the differentiation of the cells. “These are the starting cells we use in the microfluidic culture.”
The researchers first mix the cells with a liquid, which they then add to little test vessels called bioreactors.
“You can imagine such a bioreactor as a tunnel separated down the middle by a flat barrier,” LCSB researcher Edinson Lucumi Moreno, first author of the study, clarified. “One side of the tunnel we load the liquid with the cells, where it hardens into a gel under controlled temperatures. The other side we load with a medium to which we can add nutrients and substances for further differentiation of the neuronal stem cells as required.”
After only a few hours, the researchers were already able to observe changes in the neuronal stem cells, with the cells beginning to form small protuberances which later developed into the axons and dendrites characteristic of neurons.
After 30 days, 91% of the cells were neurons, with about 20% representing the desired dopaminergic neurons. Morphological and immunological tests were able to confirm the results.
The research group has illustrated that one of the major advantages of the aforementioned 3D cell culture system is that it can already be automated in its present form: The bioreactors are placed on commercially available plates that can be processed and read out by laboratory robots.
“In drug development, dozens of chemical substances can therefore be tested for possible therapeutic effects in a single step,” claimed Dr. Fleming. “Because we use far smaller amounts of substances than in conventional cell culture systems, the costs drop to about one tenth the usual.”
A further advantage is that the bioreactors can be loaded with cells originating from the skin cells of individual Parkinson’s patients. “This is an important step towards personalised drug development,” Fleming asserted.
Fleming's team and their international collaborators have expressed their next objective as lying in the study of cells from patients to test potential active pharmaceutical ingredients. Substances that garner promising results will then be tested in mice.
Photo By Uni.Lu (Neurons Made of Skin Cells)
