Stem Cells and Regeneration 의공학개론, Fall 2012 Anne J. Kim, Ph.D.

Stem Cells: A Timeline  1981 – Embryonic stem cells (ESCs) are isolated in mice  1995 – ESCs are isolated in rhesus monkeys  1998 – Researchers isolate the first human embryonic stem cells (hESCs)  2001, 2004 – Scientists claim to have cloned a human embryo  2006 – Researchers say it is possible to derive hESCs without harming human embryos  2007 – Stem cells derived from amniotic fluid are able to produce bone, liver, and brain tissue  2007 – Researchers modify a skin cell so that it acts like an embryonic stem cell

Regeneration: The action or process of regenerating or being regenerated, in particular the formation of new animal or plant tissue.  In other words, the search for the fountain of youth and the hope for immortality… Prometheus Bound, Peter Paul Rubens; The Raising of Lazarus, Vincent Van Gogh

Limb regeneration in salamanders: The arms that keep growing back… Lévesque M, Gatien S, Finnson K, Desmeules S, Villiard É, et al. (2007) Transforming Growth Factor: β Signaling Is Essential for Limb Regeneration in Axolotls. PLoS ONE 2(11): e1227. doi: /journal.pone Axolotls (urodele amphibians) can regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation. The regenerated parts all work perfectly!

Preformism vs. Epigenesis  Fully formed, miniature versions of plants and animals exist at the beginning of creation  Antonie van Leeuwenhoek looked at a sperm cell through a microscope and found this to be “true”

Preformism vs. Epigenesis  Plants and animals develop through a sequence of steps  Cells differentiate (become more specialized) and tissues and organs form from these cells  Caspar Friedrich Wolff: complete lack of organization of tissues develop into highly organized structure

Differentiation is reversible!

Symmetric cell division

Asymmetric cell division 1. Self-renews 2. Differentiates Progenitor cell Stem cell

 SELF – RENEWAL  DIFFERENTIATION

Where do we find stem cells?  Early embryos  Adult tissues  Skin, bone, blood  Brain, retina, heart  NEW! Reprogrammed adult cells!

What is stem cell research?  Understand more about development, aging, disease  Experimental model systems  Prevent or treat diseases and injuries  Cell-based therapies  Pharmaceutical development  Includes testing and drug delivery

Experimental model system Heart muscle cells beating in a petri dish! Videos by The Exploratorium

Stem cells for drug delivery More focused delivery, fewer side affects NSCs injected (no tumor) NSCs injected (tumor) Day 0Day 7 Day 14 Shah et al. Dev Neurosci 2004

Bone marrow transplant: Example of adult stem cell-based therapy

Trachea transplantation: Example of adult stem cell-based tissue regeneration

Spinal cord injury: Example of embryonic stem cell-based therapy Geron video:

Science is discovering the unknown  Stem cell field is still in its infancy  Human embryonic stem cell research is a decade old, adult stem cell research has 30-year head start  Holds hope for curing or improving treatments for 70+ diseases