Establishment of a striped catfish skin explant model for studying the skin response in Aeromonas hydrophila infections

Abstract

Teleost fish skin serves as the first line of defense against pathogens. The interaction between pathogen and host skin determines the infection outcome. However, the mechanism(s) that modulate infection remain largely unknown. A proper tissue culture model that is easier to handle but can quantitatively and qualitatively monitor infection progress may shed some lights. Here, we use striped catfish (Pangasius hypophthalmus) to establish an ex vivo skin explant tissue culture model to explore host pathogen interactions. The skin explant model resembles in vivo skin in tissue morphology, integrity, and immune functionality. Inoculation of aquatic pathogen Aeromonas hydrophila in this model induces epidermal exfoliation along with epithelial cell dissociation and inflammation. We conclude that this ex vivo skin explant model could serve as a teleost skin infection model for monitoring pathogenesis under various infection conditions. The model can also potentially be translated into a platform to study prevention and treatment of aquatic infection on the skin in aquaculture applications.

Aeromonas hydrophila Induces Skin Disturbance through Mucosal Microbiota Dysbiosis in Striped Catfish ( Pangasianodon hypophthalmus )

“…Since fish skin mucus plays a critical role in stimulating and regulating the immune response, we hypothesized that AH-challenged skin mucus could induce the observed skin immune response. To test this hypothesis, an ex vivo skin model ( 28 ) was used to create an interactive environment between the skin and the mucus ( Fig. 2A ).…”

“…3E ). Our previous study showed a significant immunostimulatory effect when inoculating the same amount of AH directly onto the skin model without mucus ( 28 ). Therefore, striped catfish skin mucus has a protective role in response to AH.…”

“…A striped catfish model system based on our previous study ( 28 ) was applied in this research. Fish skin tissue was first removed from the fish for making the ex vivo skin model and cultured in a CO 2 -free incubator at 25°C for 5 days.…”

Community Structure and Functional Annotations of the Skin Microbiome in Healthy and Diseased Catfish, Heteropneustes fossilis

“…However, some ulcerative lesions caused by only bacteria have been observed in UM epidermis ( Noga et al, 1991 ). Skin ulceration and muscular necrosis are dominated by A. hydrophila , the freshwater pathogen would cause infection-related mortality in catfish farming systems ( Siao et al, 2021 ). Infections caused the loss of 3 million pounds of farm-raised catfish in Alabama, United States, in 2017, making A. hydrophila the most prevalent pathogen in catfish ( Siao et al, 2021 ).…”

“…Skin ulceration and muscular necrosis are dominated by A. hydrophila , the freshwater pathogen would cause infection-related mortality in catfish farming systems ( Siao et al, 2021 ). Infections caused the loss of 3 million pounds of farm-raised catfish in Alabama, United States, in 2017, making A. hydrophila the most prevalent pathogen in catfish ( Siao et al, 2021 ). However, within the same species of fish, they found different mucosal microbiomes ( Butt and Volkoff, 2019 ).…”