The role of the stem cell niche in regeneration and longevity in planarians

Aging and age-related diseases have been studied for many years using model organisms including yeast, fruit flies, worms, and mice. Some studies suggest that organismal aging correlates with decreased stem cell numbers or altered stem cell function. However, it is not known whether the signals to maintain healthy stem cells come from within the stem cell or from the environment surrounding the cell, the stem cell niche. Schmidtea mediterranea is a model organism that has been used to study stem cell biology for many years. These flatworms have the ability to regenerate all of their tissues and organs from very small fragments following amputation. This remarkable regenerative capacity is due to a population of adult stem cells which make up 20-30% of the total cells in the worm. Additionally, these stem cells have been found in clusters surrounding the intestine, an area that may represent a stem cell niche for S. mediterranea. In this study, I propose to use the model organism Schmidtea mediterranea to determine how the stem cell niche maintains stem cell function and longevity.