Title

Stress-omics: A multi-omics approach to discriminate stress states in a marine mammal

Poster Number

17a

Lead Author Affiliation

Biological Sciences

Lead Author Status

Masters Student

Second Author Affiliation

Biological Sciences

Second Author Status

Masters Student

Third Author Affiliation

Biology

Third Author Status

Faculty

Fourth Author Affiliation

Biological Sciences

Fifth Author Affiliation

Director, Conservation and Biological Research

Fifth Author Status

Staff

Sixth Author Affiliation

Biology

Sixth Author Status

Faculty

Introduction

Repeated or chronic stress, such as that caused by anthropogenic activity and environmental disturbance, may affect animal health and fitness and contribute to population declines by consequential changes in food webs. However, the physiological impacts of repeated stress have not been extensively studied in wild animals, hindering development of biomarkers that conservation practitioners can use to identify chronically stressed individuals. Baseline endocrine measurements are commonly used for stress diagnosis, but they may be less robust indicators of stress than their downstream molecular mediators. We used a non-targeted, multi-omics approach to profile global changes in target gene and protein abundance in response to acute and repeated stress in northern elephant seals (Mirounga angustirostris).

Purpose

As chronic stress has not been studied in wild marine mammals, we are using integrative techniques to further the understanding of the physiological stress response in the field of comparative physiology. To do this, we are using a systems biology approach to integrate how specific genes are targeted by stress-hormones that flow through the bloodsteam after a stress response is administered, and then analyzing the functional components of those genes, known as proteins.

Method

We simulated physiological stress responses by administering adrenocorticotropic hormone to juvenile seals once daily for four days and collected blubber samples before and after the first (“acute”) and last (“chronic”) stress challenges. We isolated RNA and proteins from blubber and sequenced the transcriptome using Illumina RNA sequencing. Proteins were labeled with iTRAQ and sequenced by tandem mass spectrometry (ThermoFisher Orbitrap Fusion Tribrid). We used an RNAseq computational pipeline (Trinity v2.4) and workflows in proteomics software (Proteome Discoverer v2.2) to identify sequenced transcripts and proteins and compare their expression between stress states. Markers were annotated against the Uniprot database and functional categories enriched in the transcriptome and proteome were identified using DAVID v6.8.

Results

Our preliminary transcriptome analyses suggest that genes associated with energy-regulating hormones, lipid and ketone biosynthesis, and lipid transport/storage were differentially expressed, suggesting that regulation of lipid stores was significantly impacted by stress. We also identified 6224 proteins in 1384 protein groups from 18,887 peptide spectral matches. Preliminary functional annotation identified 69 KEGG pathways were enriched in proteome relative to the human genome background (p≤0.05). The metabolic pathways category had the highest gene count (102); other enriched pathways of interest included carbon metabolism (38 genes), glycolysis/gluconeogenesis (21 genes), fatty acid degradation (19 genes), fatty acid metabolism (15 genes), and fatty acid elongation (7 genes), among others. This suggests that proteins involved in lipid metabolism and regulation are enriched in our proteome, supporting the transcriptome data. I am currently exploring methods for differential protein expression analysis to identify changes in protein abundance in response to stress and integrate these with our transcriptome data.

Significance

This multi-omics approach is the first to examine cellular consequences and markers of repeated stress in a wild marine mammal.

Location

DeRosa University Center

Format

Poster Presentation

Poster Session

Morning 10am-12pm

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Apr 28th, 10:00 AM Apr 28th, 12:00 PM

Stress-omics: A multi-omics approach to discriminate stress states in a marine mammal

DeRosa University Center

Repeated or chronic stress, such as that caused by anthropogenic activity and environmental disturbance, may affect animal health and fitness and contribute to population declines by consequential changes in food webs. However, the physiological impacts of repeated stress have not been extensively studied in wild animals, hindering development of biomarkers that conservation practitioners can use to identify chronically stressed individuals. Baseline endocrine measurements are commonly used for stress diagnosis, but they may be less robust indicators of stress than their downstream molecular mediators. We used a non-targeted, multi-omics approach to profile global changes in target gene and protein abundance in response to acute and repeated stress in northern elephant seals (Mirounga angustirostris).