Stem cell hierarchy of the regenerative flatworm Macrostomum lignano

by Filippo Volpe (Univ, di Bologna)

Friday 10 Jan 2025, 12:00 → 13:00 Europe/Rome

Aula 8 (Dip. di Fisica - Edificio E. Fermi)

Macrostomum lignano is a free-living marine flatworm that has been gaining increasing interest in studies on ageing and regeneration, due to its outstanding regenerative ability, and its lab-friendly characteristics. Regeneration is permitted by the stem cell population of M. lignano, called neoblasts, which allow it to regenerate its body in 2-3 weeks when left with as little as 160 neoblasts, the brain, and the pharynx. In my work, I optimized and implemented an mRNA SABER-ISH protocol for M. lignano, which was then used to visualize first-time expression patterns for several cell type-specific markers. Using this protocol, I then studied three genes, including HES1-like important for the determination of stem cell hierarchy, maintenance, and regeneration in the worm. The ISH pattern of these genes is parallel with the pattern of general neoblast markers, with the germline pattern excluded, suggesting a separation in different neoblast lineages. An RNAi experiment on HES1-like resulted in depletion of the neoblasts of the worm and death, not affecting the germline, reinforcing the idea of separate neoblast lineages. HES1-like is thus proposed as a candidate master regulator for a pluripotent non-germline neoblast lineage, which is separate from the germline neoblast lineage.