-Omic Analysis of the Sepia officinalis White Body: New Insights into Multifunctionality and Haematopoiesis Regulation

Cephalopods, like
other protostomes, lack an adaptive immune system
and only rely on an innate immune system. The main immune cells are
haemocytes (Hcts), which are able to respond to pathogens and external
attacks. First reports based on morphological observations revealed
that the white body (WB) located in the optic sinuses of cuttlefish
was the origin of Hcts. Combining transcriptomic and proteomic analyses,
we identified several factors known to be involved in haematopoiesis
in vertebrate species in cuttlefish WB. Among these factors, members
of the JAK-STAT signaling pathway were identified, some of them for
the first time in a molluscan transcriptome and proteome. Immune factors,
such as members of the Toll/NF-κB signaling pathway, pattern
recognition proteins and receptors, and members of the oxidative stress
responses, were also identified, and support an immune role of the
WB. Both transcriptome and proteome analyses revealed that the WB
harbors an intense metabolism concurrent with the haematopoietic function.
Finally, a comparative analysis of the WB and Hct proteomes revealed
many proteins in common, confirming previous morphological studies
on the origin of Hcts in cuttlefish. This molecular work demonstrates
that the WB is multifunctional and provides bases for haematopoiesis
regulation in cuttlefish.