Preliminary study on expression of antimicrobial peptides in European sea bass (Dicentrarchus labrax) following in vivo infection with Vibrio anguillarum. A time course experiment. Issue 1 (March 2015)

• Record Type: Journal Article
• Authors: Meloni, Mauro; Candusso, Sabrina; Galeotti, Marco; Volpatti, Donatella
• Is Part Of: Fish & shellfish immunology. Volume 43:Issue 1(2015:Mar.)
• Page Start: 82
• Page End: 90
• Publication Date: 2015-03
• Subjects: Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2014.12.016
• Languages: English
• ISSNs: 1050-4648

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <p id="abspara0010">Antimicrobial polypeptides (AMPPs) are humoral components of the vertebrates and invertebrates innate immune system. Their potent broad spectrum antimicrobial activities have drawn the attention of the scientific community to their potential use not only as an alternative to antibiotics but also as functional targets for immunostimulants in order to enhance the host immunity. Fish synthesize a great number of these peptides but in European sea bass, an important fish species in the Mediterranean aquaculture, only a few AMPPs have been studied and these surveys have highlighted their functional role as predictive markers of stressful conditions. Many aspects concerning AMPP mode of action in the host during bacterial infections are still unknown. In this work a 72 h time course experiment, performed on juvenile sea bass intraperitoneally (i.p.) injected with a sub-lethal dose of <italic>Vibrio anguillarum</italic>, was aimed to investigate the mRNA expression of four specific AMPP genes and <italic>interleukin-1β</italic> (<italic>IL-1β</italic>) in skin, gills, spleen, and head kidney. AMPP genes were: <italic>dicentracin</italic> (<italic>DIC</italic>), <italic>histone-like protein 1</italic> (<italic>HLP-1</italic>), <italic>histone-like protein 2</italic> (<italic>HLP-2</italic>) and <italic>hemoglobin-like protein</italic> (<italic>Hb-LP</italic>). The delta–delta <italic>C</italic><sub>T</sub> method in real-time RT-PCR allowed to gain more knowledge about temporal dynamics, preferential sites of expression as well as immunological and physiological role of these molecular markers. <italic>DIC</italic> was significantly up-regulated mainly in head kidney at 1.5–3 h post-infection (p.i.). <italic>HLP-1</italic> showed an extended-time overexpression in gills and a significant up-regulation in spleen. <italic>HLP-2</italic> was interestingly overexpressed in gills at 24 h p.i., while <italic>Hb-LP</italic> showed a significant up-regulation in skin for all the 72 h trial as well as lower but always significant values either in gills or in spleen. Different was the response of <italic>IL-1β</italic> that showed a dramatic up-regulation in spleen and head kidney at 8 h p.i. whilst in gills it displayed a severe inhibition. During this survey the i.p. stimulus surely conditioned the AMPP expression in skin and gills, especially as regards the <italic>DIC</italic> that as piscidin-related gene has an important defensive role in the mucosal tissues. However, two unconventional AMPP genes such as <italic>HLP-2</italic> and <italic>Hb-LP</italic>, strictly related to the physiological mechanisms of fish, were less affected in terms of expression by the route of infection, being more evident in peripheral loci. These findings might suggest them as potential markers to be analyzed within plans of health survey in fish farms.</p> </sec> </abstract>