Archive by category | Reprogramming/Pluripotency

A small molecule replaces Sox2, and honors baseball

The standard technique for creating make differentiated cells behave like embryonic stem cells uses viruses to insert the genes cMyc, Klf4, Oct4, and Sox2 into cells, but adding these genes to cells makes them less predictable and more likely to form tumors. Researchers have been able to reprogram neural stem cell using only Oct4, but these cells are not readily available from patient biopsies and so researchers are searching for alternate techniques. New work published in Cell Stem Cell shows that a small druglike molecule can effectively replace two of the four genes typically used to generate induced pluriptotent stem cells.  Read more

p53, guardian of the genome, also blocks reprogramming

This piece, by Elie Dolgin, builds on the more-general article now up on Nature News. The tumor suppressor gene p53 is usually thought of as a master regulator that helps stave off cancer, but it’s also a major barrier to cellular reprogramming. Blocking the p53 pathway vastly improves the efficiency of transforming differentiated cells into induced pluripotent stem (iPS) cells and with fewer genes than the commonly used reprogramming recipes, new research shows. The findings, which should make it easier to derive patient-specific stem cells from any tissue, provide a bridge between tumour formation and cellular reprogramming that could force  … Read more

Round-up of regenerative medicine stories and a big, squeaking accomplishment

Two groups of researchers have at last completed a stringent test to show that induced pluripotent stem cells have the same developmental potential as embryonic stem cells: inserted into a special embryo, they can contribute to all the cells in a new mouse, litters of which have now been produced. (See the Nature news story)  … Read more

Creation of iPS pig cells could bring on humanized porkers

Posted for David Cyranoski; Cross-posted from The Great Beyond Researchers in China have made pluripotent stem cells from a pig. The cells could be useful for making humanized pig organs for transplant to humans, pig models of human disease useful for testing drugs, and for improving pig farming productivity and nutritional value. Lei Xiao, head of the research group at the Shanghai Institutes for Biological Sciences where the research was done, admits that none of these will happen for the next several years. But his creation in pigs of induced pluripotent stem (iPS)-cells which share with embryonic stem cells the  … Read more

Gene-free reprogramming in human cells

A new paper in Cell Stem Cell describes how scientists reprogrammed human cells to pluripotency without using any DNA at all. Instead, reprogramming proteins were engineered so that they could enter the nucleus. These proteins were produced in cultures of mammalian cells and secreted into the culture media. When fibroblasts derived from newborns were exposed to those cell extracts, the cells reprogrammed to teratoma-producing induced pluripotent stem (iPS) cells, a big first for human cells.  Read more