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Investigating an increase in Florida manatee mortalities using a proteomic approach
Rebecca Lazensky1,2, Cecilia Silva-Sanchez3, Kevin J Kroll1
1Department of Physiological Sciences, Center for Environmental and Human Toxicology, University of Florida, Building 471, Mowry Road, PO Box 110885, Gainesville, FL, 32611, USA.
Abstract:
Two large-scale Florida manatee (Trichechus manatus latirostris) mortality episodes were reported on separate coasts of Florida in 2013. The east coast mortality episode was associated with an unknown etiology in the Indian River Lagoon (IRL). The west coast mortality episode was attributed to a persistent Karenia brevis algal bloom or 'red tide' centered in Southwest Florida. Manatees from the IRL also had signs of cold stress. To investigate these two mortality episodes, two proteomic experiments were performed, using two-dimensional difference in gel electrophoresis (2D-DIGE) and isobaric tags for relative and absolute quantification (iTRAQ) LC-MS/MS. Manatees from the IRL displayed increased levels of several proteins in their serum samples compared to controls, including kininogen-1 isoform 1, alpha-1-microglobulin/bikunen precursor, histidine-rich glycoprotein, properdin, and complement C4-A isoform 1. In the red tide group, the following proteins were increased: ceruloplasmin, pyruvate kinase isozymes M1/M2 isoform 3, angiotensinogen, complement C4-A isoform 1, and complement C3. These proteins are associated with acute-phase response, amyloid formation and accumulation, copper and iron homeostasis, the complement cascade pathway, and other important cellular functions. The increased level of complement C4 protein observed in the red tide group was confirmed through the use of Western Blot.
Insights
Florida manatee deaths in 2013 were linked to red tide and unknown causes. Proteomic analysis revealed distinct protein changes in serum, indicating different physiological responses in manatees (Trichechus manatus latirostris).
Area of Science:
- Marine Mammal Health
- Proteomics
- Environmental Toxicology
Background:
- Two major Florida manatee (Trichechus manatus latirostris) mortality events occurred in 2013 on the Atlantic and Gulf coasts.
- The Indian River Lagoon (IRL) event had an unknown cause with signs of cold stress, while the Southwest Florida event was linked to a Karenia brevis red tide.
Purpose of the Study:
- To investigate the underlying physiological changes in manatees during these two distinct mortality episodes.
- To identify specific protein biomarkers associated with each mortality cause using proteomic techniques.
Main Methods:
- Serum samples from affected manatees and controls were analyzed using two-dimensional difference in gel electrophoresis (2D-DIGE) and isobaric tags for relative and absolute quantification (iTRAQ) LC-MS/MS.
- Key protein level changes were identified and validated, including Western Blot confirmation for complement C4-A in the red tide group.
Main Results:
- Manatees from the IRL showed elevated levels of proteins such as kininogen-1, alpha-1-microglobulin, histidine-rich glycoprotein, properdin, and complement C4-A.
- Manatees affected by red tide exhibited increased levels of ceruloplasmin, pyruvate kinase, angiotensinogen, complement C4-A, and complement C3.
- Identified proteins are involved in acute-phase response, amyloidosis, copper/iron homeostasis, and complement pathways.
Conclusions:
- Distinct proteomic profiles were observed between the IRL and red tide manatee mortality events.
- These protein changes suggest specific physiological stress responses, including inflammation and complement activation, in affected manatees.
- Proteomics offers a valuable approach for understanding manatee health and identifying causes of mortality events.
