View from the floor: ISSCR day 3

By Ben Paylor

Shinya Yamanaka, vice president of the ISSCR, soon-to-be McEwen Centre Award for Innovation recipient, and a leader in the field of iPS cell generation, opened day three of the 2011 ISSCR conference with a presentation titled “Induction of Pluripotency by Defined Factors”. The main hall was surprisingly crowded at 9:00 am given the somewhat rowdy Junior Investigator Night Club Party at This is London the night before, perhaps a testament to the significance of his work. Dr. Yamanaka addressed recent reports describing some troubling differences between iPS and hES cells. Data from his lab in Japan showed that these differences are not as dramatic as others might think, with a high degree of similarity in regards to DNA methylation, gene expression, capacity for differentiation and immunogenicity. Of interest if this new and exciting cell type is going to be clinically relevant, autologous iPS transplantation was tolerated far better than allograft ES transplantation, highlighting one of the many important aspects of iPS cells. A second story he told was about Glis1, a transcription factor which is highly expressed in unfertilized eggs and rapidly down-regulated following fertilization, and he described its ability to promote the generation of iPS cells. Using the allegory of a ball rolling from an undifferentiated state down a steep slope to a mature differentiated state, Dr. Yamanaka explained that perhaps this slope is not as steep as we have previously thought and the genetic changes required for cells to move towards a pluripotent state not as dramatic as some might think. He ended by encouraging all ISSCR members to attend the 10^th annual ISSCR meeting next year in Yokohama, and added a warming personal note by thanking the international community for its tremendous support following the recent disasters in Japan.

In the afternoon, a plenary session on “Stem Cell Metabolism and Aging” featured talks by Irina Conboy and Amy Wagers on our current understanding of how age regulates stem cell function, focusing on their work in skeletal muscle. Both presentations were well done and made reference to previous work by Dr. Conboy in which young and old mice were parabiosed together, leading to a restoration of satellite cell function in the old partner. Dr. Wagers has followed up on these reports using similar experiments to investigate age-dependent regulation of stem cell function in other tissues, and reported that similar trends were found in models of cardiac hypertrophy as well as remyelination studies. TGFß was reported to have a central role in this phenomenon, but the contribution of additional cytokines, as well as accessory inflammatory cells and metabolic regulators remains to be completely elucidated. Dr. Wagers' data on the changes in satellite cell function in different dietary conditions led smoothly into a closing joke about taking caution in one's indulgence during the reception that evening. The talks, “Modifying Regenerative Potential and Cell Fate Within Myogenic Lineage” by Dr. Conboy and “Modulators of Stem Cell Regenerative Function in Skeletal Muscle” by Dr. Wagers were very complementary and worked well to give a detailed overview of their research and its potential.