Program
Biology Graduate Program
College
Arts and Sciences
Student Level
Doctoral
Location
PAÍS Building
Start Date
10-11-2022 11:00 AM
End Date
10-11-2022 1:00 PM
Abstract
The fish skin is a crucial first line of defense against different external threats. Among these dangers, several sources of stress, such as overcrowding and transportation, are often associated to intensive aquaculture. Thus, fish requires efficient mechanisms to sense and respond to those danger signals. In fish, the skin produces a large amount of mucus, that covers and protects the whole body. Within the mucus layer, several molecules can directly interact and kill pathogens, one of them are beta-defensins. Beta-defensins are antimicrobial peptides present in almost all animals, including fish. As in humans, beta-defensins are highly expressed in the fish skin, where they shape microbiota and the innate immune response toward defeating pathogens and reestablishing physiological equilibrium. Here, we investigated the effects of acute stress associated with either elevated temperature or transportation on the expression of six beta-defensin (omDB) in rainbow trout (Oncorhynchus mykiss) skin. In the temperature stress experiment, we sampled fish kept at 16°C (control) and those exposed to increasing temperatures (19, 22, and 25°C). In the transportation stress experiment, we sampled before (control) and after 5h-transportation. From both experiments, we collect skin and blood plasma. Our data show that beta-defensins are expressed in a tissue-specific manner in rainbow trout at the steady state. For instance, omDB-1a, 1b, and 4 genes are highly constitutively expressed in the skin and swim bladder; omDB-2 and 5 in the heart, and omDB-3 in the liver and gut. In both acute stress models, beta-defensin genes were strongly modulated, which occurred at earlier time points than significant changes in stress markers, for instance, cortisol and glucose levels. Specifically, elevated temperature caused an inhibition of omDB-1b, 3, and 5 genes, while stimulated omDB-1a and 4 genes. On the other hand, transport stress resulted in an inhibition of omDB-2. Therefore, we suggest that different types of stress impact skin immunity differently as well as likely regulated skin microbiota. Our work demonstrates that beta-defensins are associated with the early fish response to acute stress in aquaculture in a stress-specific way, which is evident in the skin, a physical and functional component of the fish immune defense.
The interplay between acute stress and antimicrobial peptide modulation in the fish skin
PAÍS Building
The fish skin is a crucial first line of defense against different external threats. Among these dangers, several sources of stress, such as overcrowding and transportation, are often associated to intensive aquaculture. Thus, fish requires efficient mechanisms to sense and respond to those danger signals. In fish, the skin produces a large amount of mucus, that covers and protects the whole body. Within the mucus layer, several molecules can directly interact and kill pathogens, one of them are beta-defensins. Beta-defensins are antimicrobial peptides present in almost all animals, including fish. As in humans, beta-defensins are highly expressed in the fish skin, where they shape microbiota and the innate immune response toward defeating pathogens and reestablishing physiological equilibrium. Here, we investigated the effects of acute stress associated with either elevated temperature or transportation on the expression of six beta-defensin (omDB) in rainbow trout (Oncorhynchus mykiss) skin. In the temperature stress experiment, we sampled fish kept at 16°C (control) and those exposed to increasing temperatures (19, 22, and 25°C). In the transportation stress experiment, we sampled before (control) and after 5h-transportation. From both experiments, we collect skin and blood plasma. Our data show that beta-defensins are expressed in a tissue-specific manner in rainbow trout at the steady state. For instance, omDB-1a, 1b, and 4 genes are highly constitutively expressed in the skin and swim bladder; omDB-2 and 5 in the heart, and omDB-3 in the liver and gut. In both acute stress models, beta-defensin genes were strongly modulated, which occurred at earlier time points than significant changes in stress markers, for instance, cortisol and glucose levels. Specifically, elevated temperature caused an inhibition of omDB-1b, 3, and 5 genes, while stimulated omDB-1a and 4 genes. On the other hand, transport stress resulted in an inhibition of omDB-2. Therefore, we suggest that different types of stress impact skin immunity differently as well as likely regulated skin microbiota. Our work demonstrates that beta-defensins are associated with the early fish response to acute stress in aquaculture in a stress-specific way, which is evident in the skin, a physical and functional component of the fish immune defense.
