Proteomic profiles of male and female Caligus rogercresseyi: first approach to assess differential protein expression

Abstract

Caligidosis is a disease that affects salmonids in sea and estuaries of the Chilean coast, with a negative impact in the aquaculture activity, producing great economic damage to salmon farming. This parasitic disease is caused by the marine ectoparasite Caligus rogercresseyi, commonly known as “Caligus”. In recent years, our understanding about the biology of Caligus has been increased by the use of “omics” tools such as genomics and transcriptomics. Indeed, progress in these areas revolutionize our understanding about the physiology of this parasite, in particular, the metabolic process and the invasive mechanisms associated with infestation. However, the knowledge of the changes in protein expression levels during the different stages of the life cycle or under stress conditions of an organism, as well as the differences between sexes, have a very interesting role in the development of specific and effective pharmacological tools against this parasite. Nevertheless, the proteomic information about this parasite is insufficient. In this study, we evaluated differential expression of proteins between males and females C. rogercresseyi not exposed to antiparasitic treatments, using a tandem mass tags (TMT)-based proteomic approach, which allows the simultaneous identification and quantification of protein expression profiles from multiple samples in a single LC-MS/MS analysis. Here, we report the first advance of the proteomic analysis from male and female C. rogercresseyi. By TMT we detect 1666 proteins, of which 1307 were expressed in both males and females. However, within this group of proteins, the differential expression between males and females was detected in 688 proteins. Furthermore, between the proteins expressed exclusively in each sex, 148 proteins were detected exclusively males and 211 proteins in females. Several of the proteins described here have previously been associated with changes in their transcriptional expression levels in response to different antiparasitic drugs. The sex-biased protein expression described in this work makes sense with the different antiparasitic sensitivities observed between males and females of C. rogercresseyi.This work is the first mass identification analysis of proteins in C. rogercresseyi in which we definitively established the existence of a sex-biased protein expression.