In 1983, Tom Cruise played the character ‘Stefan Djordjevic’ in the movie “All the Right Moves” opposite Lea Thompson. In “All the Right Moves,” Mr Cruise plays “a headstrong high school football star who dreams of getting out of his small Western Pennsylvania steel town with a football scholarship.” He is hampered by, among other things, his small town upbringing and meager origins.
It turns out, Mr Cruises’ character has something in common with Induced Pluripotent Stem Cells…they too are held back by where they came from and who they are/were.
“Dr. George Daley, director of the Stem Cell Transplantation Program at Children’s Hospital Boston and a Howard Hughes Medical Institute investigator, and colleagues reported in the journal Nature that iPS cells retain an “epigenetic memory” of their origins; they remember whether they came from skin or muscle or blood.” Via
[Epigenetic memory is a process by which changes in gene expression are passed on through mitosis or meiosis through factors other than DNA sequence. Epigenetic memory in stem cells is a limiting factor...read: "not good."]
Cells, it turns out, remember where they came from. Four years ago, scientists made a breakthrough in stem cell research, when they discovered how to turn back the developmental clock on skin cells, muscle cells, and other “adult” cells so the cells would behave like embryonic stem cells. These induced pluripotent stem cells (iPS cells) were touted as an alternative to the ethically contentious embryonic stem cells.
Now, though, two groups of Howard Hughes Medical Institute researchers report that iPS cells retain a genetic memory of their tissue of origin. In a sense, the iPS cells “remember” that they came from skin, muscle, blood, and so on. This memory impedes the transformation of iPS cells into other types of cells, a prospect that has deep implications for researchers working with these kinds of cells, say HHMI investigator George Q. Daley and HHMI early career scientist Konrad Hochedlinger, who led the two research groups. The scientists worked independently but shared manuscripts and coordinated joint publications on July 19, 2010 in Nature (Daley) and Nature Biotechnology (Hochedlinger).
“But iPS [induced pluripotent stem cells] cells often don’t function as well as embryonic cells, and our new research offers an explanation as to why that is the case.” – George Q. Daley
Creating iPS cells is an important research tool because the technique can be used to generate disease-specific stem cell lines that, like embryonic stem cells, can develop into many cell types.
“The backdrop to this research is that a lot of people have the impression that iPS cells are the equivalent of embryonic stem cells,” says Daley. “That has been used as an argument that we do not need to keep studying embryonic stem cells. But iPS cells often don’t function as well as embryonic cells, and our new research offers an explanation as to why that is the case.”…