I currently teach three courses in the Biology Department, our sophomore-level Cells and Physiology course, an upper-level elective in Developmental Biology, and a non-majors class in Keene State’s Integrative Studies Program called Stem Cells and Regeneration. These courses involve an integrated lecture/lab approach that engages students in original discovery-based research projects focused on planarian regeneration (see research description below). Previous students have made significant contributions to our knowledge in this area, including the discovery of new genes required for initiation of the regenerative process.
The goal of the field of regenerative medicine is to develop treatments enabling the replacement of lost or damaged body parts. Some animals naturally exhibit this capacity and therefore provide ideal experimental subjects for studying cellular and molecular mechanisms of regeneration. Research in my laboratory deals with one such model organism – the planarian Schmidtea mediterranea. This aquatic flatworm has the remarkable ability to form entirely new individuals, complete with nervous, digestive, and reproductive systems, from tiny body fragments. My students and I are using the recently completed S. mediterranea genome sequence to investigate the genetic basis of this phenomenon. Specifically, we are exploring how a genetically programmed form of cell death resizes and reshapes planarian tissues following amputation to restore anatomical scale and proportion. This work will provide new mechanistic insight into fundamental processes of animal regeneration, and potentially, new avenues for the development of clinical interventions in the field of regenerative medicine.
Left – Regeneration in Schmidtea mediterranea. Anterior is to the top. Decapitated animals regenerate missing head tissues in approximately 7 days. Scale bar = 200 mm.
Right – Cell Death in Planarian Regeneration. Adult animals were amputated as shown (white line) at time 0. Regenerating head and tail fragments were then fixed and stained by TUNEL to visualize temporal and spatial changes in the levels of dying cells (from center left, 4 hours, 3 days, and 14 days post-amputation). Scale bars = 100 mm. See Pellettieri et al., Developmental Biology, 2010 for details.
Bender, C., Fitzgerald, P., Tait, S., Llambi, F., McStay, G., Tupper, D., Pellettieri, J., Sánchez Alvarado, A., Salvesen, G., and Green, D. 2012. Mitochondrial pathway of apoptosis is ancestral in metazoans. P.N.A.S. USA. 109(13):4904-4909.
Pellettieri, J., Fitzgerald, P., Watanabe, S., Mancuso, J., Green, D., and Sánchez Alvarado, A. 2010. Cell death and tissue remodeling in planarian regeneration. Developmental Biology, 338(1): 76-85.
Pellettieri, J., and Sánchez Alvarado, A. 2007. Cell turnover and adult tissue homeostasis – from humans to planarians. Annual Reviews in Genetics. 41: 83-105.
Stitzel, M. L., Pellettieri, J., and Seydoux, G. 2006. The C. elegans DYRK kinase MBK-2 marks oocyte proteins for degradation in response to meiotic maturation. Current Biology. 16(1): 56-62.
Pellettieri, J., Reinke, V., Kim, S.K., and Seydoux, G. 2003. Coordinate activation of maternal protein degradation during the egg-to-embryo transition in C. elegans. Developmental Cell. 5(3):451-462.
Pellettieri, J., and Seydoux, G. 2002. Anterior-posterior polarity in C. elegans and Drosophila – PARallels and differences. Science. 298(5600): 1946-1950.
Blaisdell, C., Pellettieri, J., Loughlin, C., Chu, S., and Zeitlin, P. 1999. Keratinocyte growth factor stimulates CLC-2 expression in primary fetal rat distal lung epithelial cells. American Journal of Respiratory Cell and Molecular Biology. 20(4): 842-847.