Analysis of the lake trout heart, blood, liver, and brain proteome using evolutionary proteomics

Abstract

IntroductionSalvelinus namaycush (lake trout) is a top‐predator fish in the Great Lakes region. The Great Lakes Fish Monitoring and Surveillance Program (GLFMSP) use lake trout as a bioindicator of chemical stress by monitoring the concentrations of persistent, bioaccumulative and toxic (PBT) chemicals in their bodies. Studies have shown that elevated concentrations of PBTs can cause changes in transcribed genes, translated mRNAs, proteins produced, and post‐translational modifications in aquatic species. Though lake trout is used to monitor chemical concentrations for over 50 years, there is very little information available on the proteome of this species. A well‐developed protein database for the lake trout would help elucidate the effects of PBT chemicals on this species providing a direct health metric for the Great Lakes ecosystem.MethodsIn this study, heart, blood, brain, and liver samples from lake trout were analyzed by SDS‐PAGE, followed by in‐gel trypsin digestion and analysis by nanoLC‐MS/MS. The raw data was searched against different NCBI and UniProtKB databases in Mascot Daemon and the output was analyzed by Scaffold 4.3 software. Databases used include Actinopterygii, Salmonidae, Salvelinus, as well as the highly studied species Oncorhynchus mykissand Danio rerio.Preliminary DataPreviously, our group has reported a large number of proteins for lake trout liver, heart and blood (Dupree et al., Proteomics, 2019, PMID: 31578773 and Dupree et al., Proteomics, 2021, PMID: 34676671). In lake trout liver we identified 4194 proteins using the NCBI databases and 3811 potential protein hits in the UniProtKB databases. In the blood and heart we identified 838 and 580 proteins, respectively, using NCBI databases and 1180 and 561 potential protein hits for the heart and blood, respectively in BR2. A lake trout brain proteomics analysis completed using an in‐house SDS‐PAGE, followed by in gel digestion and nanoLC‐MS/MS analysis. The Mascot database search is underway. Once protein hits are cataloged, BLAST and Scaffold‐based comparisons of the liver, heart, blood and brain will be performed. Additional search of the data against the other fish relatives will also be completed. Through this process, evolutionary relationships for the lake trout species will also be explored. The current study will add to our understanding of the lake trout proteome that will be used to understand the biochemical/physiological effects of legacy PBT chemicals in the Great Lakes ecosystem.Novel AspectUse of four types of lake trout tissue together to develop a protein database for the species.