Investigating the gene expression profiles of rehabilitated Florida manatees (Trichechus manatus latirostris) following red tide exposure

Abstract

To investigate a Florida manatee (Trichechus manatus latirostris) mortality event following a red tide bloom in Southwest Florida, an RNA sequencing experiment was conducted. Gene expression changes in white blood cells were assessed in manatees rescued from a red tide affected area (n = 4) and a control group (n = 7) using RNA sequencing. The genes with the largest fold changes were compared between the two groups to identify molecular pathways related to cellular and disease processes. In total, 591 genes (false discovery rate <0.05) were differentially expressed in the red tide group. Of these, 158 were upregulated and 433 were downregulated. This suggests major changes in white blood cell composition following an exposure to red tide. The most highly upregulated gene, Osteoclast associated 2C immunoglobulin-like receptor (OSCAR), was upregulated 12-fold. This gene is involved in initiating the immune response and maintaining a role in adaptive and innate immunity. The most highly downregulated gene, Piccolo presynaptic cytomatrix protein (PCLO), was downregulated by a factor of 977-fold. This gene is associated with cognitive functioning and neurotransmitter release. Downregulation of this gene in other studies was associated with neuronal loss and neuron synapse dysfunction. Among the cellular pathways that were most affected, immune response, including inflammation, wounds and injuries, cell proliferation, and apoptosis were the most predominant. The pathway with the most differentially expressed genes was the immune response pathway with 98 genes involved, many of them downregulated. Assessing the changes in gene expression associated with red tide

Marine Neurotoxins’ Effects on Environmental and Human Health: An OMICS Overview

“…Later, a study on white blood cells, collected on manatees rescued from a red tide, confirmed the involvement of the immune response [23]. Using RNA-Seq, Lazensky et al [23] showed that immune response (inflammation, wounds, and injuries), cell proliferation, and apoptosis were the most predominant cellular pathways dysregulated (e.g., OSCAR 12 fold) by red tide. Furthermore, neurodegenerative pathways were particularly affected.…”

“…Upregulation of the immune and neurodegenerative pathways. RNA-Seq [23] Tursiops truncatus BTX as haptens that induce an inflammatory immune response.…”

“…Herein, the application of sequencing has led to a drastic increase in gene candidates. Therefore, these results can aid researchers in further understanding the health effects of HAB on marine species and improve species rehabilitation practices and the treatment of HAB illnesses [23]. First of all, Cammen et al [24] compared, by restriction site-associated DNA (RAD) sequencing, the dolphins that died during unusual mortality events due to HAB exposure with those from the same geographic areas that survived HAB events.…”

“…Cammen et al [24] hypothesized that although BTX are unlikely to be antigenic due to their small size, these toxins may act as haptens that induce an inflammatory immune response [99]. Later, a study on white blood cells, collected on manatees rescued from a red tide, confirmed the involvement of the immune response [23]. Using RNA-Seq, Lazensky et al [23] showed that immune response (inflammation, wounds, and injuries), cell proliferation, and apoptosis were the most predominant cellular pathways dysregulated (e.g., OSCAR 12 fold) by red tide.…”

Red Tide Outreach in Florida: Message Framing, Environmental Emotions, and Support for Mitigation

“…Red tide HABs are predominantly composed of the toxic dinoflagellate Karenia brevis, which produces potent natural neurotoxins known as brevetoxins [8]. Red tides occur when environmental conditions favorable to K. brevis cause rapid algal population growth and release brevetoxins into the surrounding environment in high concentrations [9]. K. brevis easily breaks apart in the surf, disperses into marine waters [10], and becomes aerosolized [11].…”