Title

Development of a biomarker panel for identifying stressed marine mammals

Poster Number

3

Lead Author Affiliation

Biological Sciences

Lead Author Status

Masters Student

Introduction

Anthropogenic disturbances in marine ecosystems can have detrimental effects on the survival of marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoids, altering expression of target genes such as metabolic enzymes. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. We previously characterized endocrine and metabolic profiles and identified genes that were differentially expressed in response to single and repeated adrenocorticotropic hormone (ACTH) administration in juvenile northern elephant seals. Upregulated blubber genes in response to repeated ACTH administration include encoding lipid particle proteins, oxidative stress enzymes, adipokines, and lipid metabolism enzymes. Downregulated genes include inhibitors of adipogenesis, gluconeogenesis and inflammation.

Purpose

Our objective was to develop a biomarker panel of stress that can discriminate between acute and chronic stress states in marine mammals.

Method

To validate our biomarker panel, we collected blood and blubber samples from 30 juvenile northern elephant seals of varying body condition (standard length/axillary girth) and baseline stress states. Endocrine (cortisol, aldosterone, total triiodothyronine 3 and reverse T3) and metabolic (triglyceride) markers were measured in blood using immunoassays and colorimetric assays. Expression of candidate genes in blubber was measured using real-time quantitative polymerase chain reaction. The data was analyzed using different statistical analyses (i.e. Shapiro-Wilk test for normality, Pearson correlations, Spearman correlations).

Results

Expression levels of 11, out of the 14 gene markers studied, were significantly correlated with elevated cortisol, reverse triiodothyronine, and decreased triglycerides, triiodothyronine and body condition. Aldosterone was not correlated with any of the gene markers.

Significance

These markers provide insights into molecular mediators of the stress response and can be used as a potential diagnostic panel for differentiating stress states in marine mammals.

Location

DeRosa University Center

Format

Poster Presentation

Poster Session

Morning

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Development of a biomarker panel for identifying stressed marine mammals

DeRosa University Center

Anthropogenic disturbances in marine ecosystems can have detrimental effects on the survival of marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoids, altering expression of target genes such as metabolic enzymes. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. We previously characterized endocrine and metabolic profiles and identified genes that were differentially expressed in response to single and repeated adrenocorticotropic hormone (ACTH) administration in juvenile northern elephant seals. Upregulated blubber genes in response to repeated ACTH administration include encoding lipid particle proteins, oxidative stress enzymes, adipokines, and lipid metabolism enzymes. Downregulated genes include inhibitors of adipogenesis, gluconeogenesis and inflammation.