Researchers from the University of Washington School of Medicine in Seattle, US, have developed a new robotic system to automate the production of human mini-organs derived from stem cells. The ability to rapidly, mass-produce organoids promises to expand their use in basic research and drug discovery. The results were published may 17, 2018 in Cell Stem Cell.
“This is a new ‘secret weapon’ in our fight against disease”, – said Benjamin Freedman, assistant professor of medicine, Division of Nephrology, at the UW School of Medicine, who led the research effort.
Freedman explained that the traditional way to grow cells for biomedical research is to culture them as flat, two-dimensional sheets, which are overly simplistic. In current years, investigators have been increasingly effective in applying the technique of forming three-dimensional structures called mini-organs or organoids from stem cells. By their external signs and properties, they are in many respects reminiscent of organs at their embryonic stage of development.
Although this makes organoids ideal for biomedical research, mass production is still problematic. According to the authors of the study, the new robotic technology is the most promising in solving this problem.
Despite the fact that such approaches have been successful with adult stem cells, in this paper, scientists for the first time used pluripotent stem cells with universal properties and capable of creating any type of organ.
For this process, the liquid-handling robots introduced the stem cells into plates that contained as many as 384 miniature wells each, and then coaxed them to turn into kidney organoids over 21 days. Each microwell typically contained ten or more organoids, and each plate contained thousands of organoids. With a speed that would have impressed Henry Ford’s car assembly line, the robots could harvest many plates in a fraction of the time.
“Ordinarily, just setting up an experiment of this magnitude would take a researcher all day, while the robot can do it in 20 minutes”, – said Freedman. “On top of that, the robot doesn’t get tired and make mistakes. There’s no question. For repetitive, tedious tasks like this, robots do a better job than humans.”
The researchers additionally educated robots processing and analysis produce organoids. Scientists used an automated, cutting-edge technique called single cell RNA sequencing to identify all the different types of cells found in the mini-organs.
“We established that these organoids do resemble developing kidneys, but also that they contain non-kidney cells that had not previously been characterized in these cultures”, – said Dr. Jennifer Harder, a kidney disease specialist.
“These findings give us a better idea of the nature of these organoids and provide a baseline from which we can make improvements”, – Freedman said.
“The value of this high-throughput platform is that we can now alter our procedure at any point, in many different ways, and quickly see which of these changes produces a better result.”
To demonstrate this, the researchers have discovered a way to significantly increase the number of blood vessel cells in their organoids to create them more similar real kidneys.
Scientists also used new technology to search for drugs. In one such experiment, they created organoids with mutations that cause polycystic kidney disease – a hereditary disease that often leads to kidney failure and occurs in 1 person out of 600 all over the world.
With this disease, tiny tubes in the kidneys expand, forming cysts that displace healthy tissue.
In their experiment, the researchers worked on organoids with polycystosis in a number of compounds. They found that one of the factors known as blebbistatin, blocking the protein myosin, provoked a significant increase in the number and size of cysts.
“This was unexpected, since myosin was not known to be involved in polycystic kidney disease”, – Freedman said.
Myosin, which is well-known for its role in muscle contraction, may allow kidney tubules to increase and contract. If it is not working properly it might lead to cysts, Freedman explained.
“It’s definitely a pathway we will be looking at”, – he said.