Post-reproductive neurodegeneration in cuttlefish Sepia officinalis: identification of molecular mechanisms

Cuttlefish are cephalopods with a short life cycle (20-22 months) that undergo rapid degeneration of the CNS, known as post-reproductive degeneration, with rapid ageing, the immediate consequence of which is the abrupt cessation of egg-laying and the death of females that are still fertile. The various effects observed during the critical phase will be studied through 3 non-exclusive working hypotheses, using approaches combining transcriptomics, proteomics, peptidomics and immunohistochemistry:

An initial hypothesis linked to the loss of perception observed in the animal at the end of its life will be explored. The identification and monitoring of the expression of central nervous system biomarkers potentially involved in neuronal ageing mechanisms will be carried out at 2 key periods in the life cycle of cuttlefish: sub-adult and degenerating individuals (end of life).

The second hypothesis concerns the involvement of the neuroendocrine system. For this line of research, the expression of 38 neuropeptide/neurohormone families identified by the PHYPAQ team will be monitored during the two key periods mentioned above. Particular attention will be paid to certain families that are probably involved in feeding behaviour.

Finally, certain lesions observed in degenerating animals may indicate a failure of the immune system. A comparative analysis of the white body (haematopoietic organ) using NGS expression monitoring will help identify any disturbances at this level.