Research

Our lab seeks to understand the cellular basis for aging of organisms. One prominent hypothesis to explain why organisms age is that cellular damage accumulates over time. Certain populations of cells may be more susceptible to aging-related damage than others. For example, adult stem cells, that act to maintain various tissues in adult organisms, persist throughout the lifetime of the organism, and thus may accumulate more damage than non-stem cell populations. Also, due to their role in replenishing tissues after damage or natural turnover, changes in the stem cell population over time would likely have significant effects on the whole organism.

In our research, we study stem cells that maintain the adult testis of the fruit fly, Drosophila melanogaster. These include both germline stem cells, which produce sperm cells that contribute to future generations, and somatic stem cells, which assist in sperm production, but which will not be passed on to the next generation. Stem cells in the fruit fly testis are an outstanding model for aging studies, as the stem cells can be easily identified, and can be genetically manipulated. We have found that although the number of germline stem cells does not change dramatically during aging, these cells divide less frequently. Interestingly, in flies which are long lived due to a mutation in a gene called methuselah , this slowing of stem cell division is not observed. Currently we are investigating how methuselah acts to regulate stem cell aging, and we are testing the hypothesis that accumulation of oxidative damage contributes to this aging. Because many aspects of stem cell function are conserved between fruit flies and humans, this research will hopefully provide a better understanding of what contributes to aging in humans.

Representative Publications

Wallenfang, M. R., Nayak, R., and DiNardo, S. (2006) Dynamics of the male germline stem cell population during aging of Drosophila melanogaster. Aging Cell 5:297-304.