Using the Carnivorous Sponge Lycopodina hypogea as a Nonclassical Model for Understanding Apoptosis-Mediated Shape Homeostasis at the Organism Level

Stephen Baghdiguian (1) , Emilie Le Goff (1) , Laure Paradis (1) , Jean Vacelet (2) , Nelly Godefroy (1)

1 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier
2 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale

The dynamic equilibrium between death and regeneration is well established at the cell level. Conversely, no study has investigated the homeostatic control of shape at the whole organism level through processes involving apoptosis. To address this fundamental biological question, we took advantage of the morphological and functional properties of the carnivorous sponge Lycopodina hypogea. During its feeding cycle, this sponge undergoes spectacular shape changes. Starved animals display many elongated filaments to capture prey. After capture, prey are digested in the absence of any centralized digestive structure. Strikingly, the elongated filaments actively regress and reform to maintain a constant, homeostatically controlled number and size of filaments in resting sponges. This unusual mode of nutrition provides a unique opportunity to better understand the processes involved in cell renewal and regeneration in adult tissues. Throughout these processes, cell proliferation and apoptosis are interconnected key actors. Therefore, L. hypogea is an ideal organism to study how molecular and cellular processes are mechanistically coupled to ensure global shape homeostasis.

Mots clés: sponges; Lycopodina hypogea; morphogenesis; homeostasis; apoptosis; proliferation; caspases; stem cells

Domaines: Biologie animale

Stephen Baghdiguian, Emilie Le Goff, Laure Paradis, Jean Vacelet, Nelly Godefroy. Using the Carnivorous Sponge Lycopodina hypogea as a Nonclassical Model for Understanding Apoptosis-Mediated Shape Homeostasis at the Organism Level. Foundations, 2023, 3, pp.220-230. ⟨10.3390/foundations3020018⟩. ⟨hal-04458066⟩