2021 ECM Niche of Planarian Stem Cells Regulating Potency and Lineage Progression in Tissue Maintenance and Regeneration

The extracellular matrix (ECM) provides a precise physical and molecular environment for cell maintenance, self-renewal, and differentiation in the stem cell niche. However,  the nature and organization of the ECM niche are not well understood. The adult freshwater planarian Schmidtea mediterranea maintains a large population of pluripotent and multipotent stem cells (neoblasts), presenting an ideal model to study the role of the ECM niche in stem cell regulation. We tested the function of 165 planarian homologs of ECM and ECM-related genes in neoblast regulation. We identified the collagen gene family as one with differential effects in promoting or suppressing the proliferation of neoblasts. col4-1 encoding a type of IV collagen a-chain had the strongest effect. RNA interference (RNAi) of col4-1 impaired tissue maintenance and regeneration, causing tissue regression. We further provide evidence for an interaction between type IV collagen, the discoidin domain receptor, and neuregulin-7 (NRG-7), which constitutes a mechanism to regulate the balance of symmetric and asymmetric division of neoblasts via the NRG-7/EGFR pathway. 

Danny Chan is professor and Director of the School of Biomedical Science at the University of Hong Kong, and Assistant Dean for research and research postgraduate studies at the Faculty of Medicine. 

His research interest is in skeletal biology, focusing on the development, growth, and degenerative processes of the skeleton in health and disease. He has a particular interest in rare diseases of the skeleton. His research has contributed to key understandings in skeletal biology, studying cartilage/bone development and growth in health and disease. The emphasis is on genes regulating the linear growth of long bones, the formation of a synovial joint, and the intervertebral disc of the spine. The approach is to identify novel disease genes and to model the disease in mice to define the precise molecular and developmental changes.  He leverages scientific discoveries to formulate therapeutic strategies in stem cell and regenerative medicine. 

This webinar will take place on Zoom.

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