A group of three MU life scientists using fibroblasts harvested from pigs’ connective tissue have created stem cells that they say may advance efforts to overcome “differentiation” problems holding back stem-cell therapies.
Stem cells are so called because their ability to differentiate into any cell type places them at the beginning, or stem, of all cell generation. They are of intense interest to researchers, who say stem cells are poised to play a role in tissue or organ regeneration, could be used to treat brain disorders such as Alzheimer’s and Parkinson’s, could help replace diseased heart tissue in those with cardiac illnesses, could boost insulin-producing cells in Type 1 diabetics and could unravel mysteries related to cells’ genetic coding.
Key to realizing this potential, says R. Michael Roberts, Curator’s Professor of Animal Science and Biochemistry at MU and member of the National Academy of Sciences, is controlling the signals that guide stem cell’s differentiation. “Right now, we researchers have not answered questions concerning how to make stem cells develop into just one type of cell, such as those of liver, kidney or blood cells, rather than a mixture,” Roberts says. But, he adds, they’re getting closer.
In a new study, Toshihiko Ezashi, a research assistant professor of animal sciences, took fibroblasts, cells found in connective tissue, from a fetal pig. Ezashi, along with Roberts and Bhanu Telugu, a postdoctoral fellow in animal sciences, then inserted four “re-programming” genes into those fibroblasts.
After the procedure, the scientists found the fibroblasts now “believed” they were stem cells, and took on many of the properties of stem cells derived from embryos. Like embryonic stem cells, for example, their re-programmed fibroblasts could now differentiate into many, possibly all, of the more than 250 cell types found in the body of an adult pig.
Researchers refer to cells of this type as “induced pluripotent stem cells,” so called because they are not derived from embryos and no cloning technique is used to obtain them.
“Now that we have been able to turn regular cells into stem cells, we need to learn how to make the right type of tissue and then test putting that new tissue back into the animal,” Roberts says.
This will have the dual benefit of not only advancing scientists’ understanding of differentiation, but of providing a valuable non-human research model for future studies, Roberts says.
“The pig is a good model because it resembles the human much more than does the mouse. It lives a long time, and it would be possible, in this case, to create stem cells from a very young pig, even a newborn pig, to develop these pluripotent cells. [We can] then use them as a course of tissue grafts to follow the safety and efficiency of these cells—in other words, whether these cells work—in the pig as it grows older.”