Meeting Abstract
Although all animals can heal wounds, only some are capable of regenerating from major tissue losses. Little is known about how and why most animals have lost the ability of whole-body regeneration. To answer these questions, we study two evolutionary cousins: the freshwater planarian, which is an immortal flatworm with unparalleled regenerative ability throughout the animal kingdom, and the parasitic flatworm schistosome, which infects hundreds of millions people and causes one of the most prevalent infectious diseases. Unlike planarians, schistosomes only have limited regenerative ability. Planarian regeneration relies on the pluripotent and tissue-specialized neoblasts to differentiate and produce all missing cell types under the guidance of a set of patterning signals expressed in muscle cells. To test if schistosomes have similar cell types, we have developed a single-cell transcriptomic analysis method (self-assembling manifolds mapping, SAMap) to construct a comprehensive cross-species comparative map of schistosome and planarian cell types, a task that has not been possible previously. This method has allowed us to identify schistosome cell types that are homologous to all planarian pluripotent and tissue-specialized neoblast populations, as well as muscle cells that express the patterning cues. Enabled by this cross-species comparison, We are now systematically examining the functions of these homologous stem cell populations and dissecting the gene circuits that control the fate of these cells.
