Project description:Studies of tissue regeneration and host-pathogen interactions using the model planarian Schmidtea mediterranea have been performed at an experimental temperature of 19?°C. S. mediterranea planarians exposed to 19?°C-32?°C were observed for survival, mobility, feeding and regeneration for three months and elimination of the Staphylococcus aureus pathogen over six days. S. mediterranea planarians died at 30?°C-32?°C after 18 days of observation but tolerated temperatures of 19?°C up to 28?°C with non-significant differences in mobility and feeding behavior. Genetic malleability tested by RNAi feeding was still efficient at 26?°C and 28?°C. Concerning the immune capacity of planarians, we reported an exacerbation of the immune response in worms infected by S. aureus at 26?°C and 28?°C. These observations suggest a temperature modulation of planarian stem cells and illustrate the importance of modulating experimental temperature when using planarians as model organisms to study regeneration and immune response.
Project description:Proper function and repair of the digestive system are vital to most animals. Deciphering the mechanisms involved in these processes requires an atlas of gene expression and cell types. Here, we applied laser-capture microdissection (LCM) and RNA-seq to characterize the intestinal transcriptome of Schmidtea mediterranea, a planarian flatworm that can regenerate all organs, including the gut. We identified hundreds of genes with intestinal expression undetected by previous approaches. Systematic analyses revealed extensive conservation of digestive physiology and cell types with other animals, including humans. Furthermore, spatial LCM enabled us to uncover previously unappreciated regionalization of gene expression in the planarian intestine along the medio-lateral axis, especially among intestinal goblet cells. Finally, we identified two intestine-enriched transcription factors that specifically regulate regeneration (hedgehog signaling effector gli-1) or maintenance (RREB2) of goblet cells. Altogether, this work provides resources for further investigation of mechanisms involved in gastrointestinal function, repair and regeneration.
