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Shin-Ichi NISHIKAWA, M. D., Ph. D. 
The
stem cell system can be thought of as a means by which organisms maintain
cell renewal. All forms of life require the endless recycling of both
materials and energy, making it impossible for either organisms or individual
cells to live independent of their environments. In bodies made up of
many cells working in cooperation, such as our own, the need to replace
and renew is not limited to simple materials and energy supply; the constant
generation of new cells is also essential to the maintenance of the individual,
a process that has developed in the evolution of multicellular life. In
this sense, the process of cell renewal in maintaining the body's
integrity and function provides a meaningful example of the relationship
of the cell to the organism, the individual to the whole, which we hope
to explore more fully using the biology of stem cells as our model.
We
are especially interested in the question of how cells maintain the never-ending
self-renewal that sustains the organism as a whole. This will require,
at the very least, solving the riddles of two essential processes. The
first of these is the need for old cells destined for replacement to be
able to disengage or otherwise be dislocated from their environmental
milieux. The second is the requirement for preparing new cells in replacement.
To investigate the first of these mechanisms, our group uses a system
for labeling cells with special dyes, which allows us to monitor their
location and behavior. We have also developed a system for differentiating
embryonic stem (ES) cells in culture to study the second question of new
cell production. In addition to these two central themes, other members
of the laboratory are studying angiogenesis, the formation of blood vessels,
as blood supply is an absolute requirement to the establishment and maintenance
of any deep or extensive biological tissue. These three ongoing research
projects within our lab allow us to explore the problem of cell renewal
in self-maintenance from multiple angles, an approach which we hope will
provide new insights into this fundamental process.
