Researchers from the Eli and Edythe Center for Regenerative Medicine along with others from the UCLA Stem Cell Research Center have succeeded in converting human stem cells into sensory interneurons , which are the receptor cells that make up our sense of touch.
This procedure could be an important step in designing stem cell therapies to help restore tactile sensation in people with paralysis who have lost sensation in parts of the body . The study was led by Samantha Butler, Professor of Neurobiology at UCLA and a member of the Center for Stem Cell Research, and published in the journal Stem Cell Reports .
Touch receptor cells, which are a type of neurons located in the spinal cord, are responsible for transmitting information from the entire body to the central nervous system , which activates the sense of touch. The lack of sensitivity to touch affects people with paralysis who often do not feel contact with other people and do not perceive pain, which puts them in danger of being burned if they inadvertently touch a hot surface . According to Butler, “Research has almost always focused on getting people with paralysis to walk again. It seems that the ability to regain the sense of touch is not that important, but to be able to walk again we need the ability to feel contact. and the sense of space in the body. Actually, both processes go hand in hand. “
In previous research published in eLife in September, Butler and his colleagues reported that a family of proteins called bone morphogenetic proteins sent signals that influenced the development of touch receptor neurons in chicken embryos.
The new research has built on that discovery and applied it to human stem cells in the laboratory. By applying a type of bone morphogenetic proteins called BMP4 together with retinoic acid signaling molecules to human embryonic stem cells, they obtained a mixture of two types of touch receptor interneurons. The DI1 sensory interneurons activated the sense of proprioception, which is what informs the body of the position of the muscles and their position in space , and the DI3 allow us to feel the pressure on the skin .
The researchers found an identical combination to that when they incorporated signaling molecules into induced pluripotent stem cells, which are created by restoring the mature cells of the patient’s own skin. This method makes it possible to produce stem cells capable of creating any type of cells with the same genetic code as the person from which they come. The ability to manufacture touch receptor cells through this system can help regain sensitivity without affecting the immune system . These cells could be used in clinical procedures with people suffering from paralysis .
At the moment, Butler and his team are implanting dI1 and dI3 sensory interneurons into the spines of mice to integrate them into the nervous system and make them work. This is a crucial step in discovering the therapeutic potential in humans.
