The expectations for stem cell transplantation to treat diseases
have been high. However, accumulating evidence indicates that
stem cell homing is a very tough issue, and stem cell
transplantation seems to result in a majority of “homeless stem
cells”. Stem cells’ innate ability to travel to the right place
in the body is very limited. Only a very small fraction of cell
grafts will dock properly. The rest will be eliminated by
apoptosis or become problematic. On the other hand, human
embryonic stem cells (hESCs) are notoriously difficult to
maintain due to spontaneous differentiation and apoptosis within
culture. Understanding mechanisms that regulate hESC self-
renewal, differentiation, and apoptosis will enhance our ability
to manipulate hESCs and to realize their potential for
regenerative medicine. Previous studies on the regulation of
stem cell behavior have focused largely, if not exclusively, on
the role of nuclear genes. The present proposal seeks to expand
this existing paradigm. We hypothesize that m