Ontogeny and modulation after PAMPs stimulation of β-defensin, hepcidin, and piscidin antimicrobial peptides in meagre ( Argyrosomus regius )

Abstract

Antimicrobial peptides (AMPs), components of innate immunity, play an important role in protecting fish. In this study we report the molecular cloning of full open reading frames and characterization of expression of three AMP genes (β-defensin (defb), hepcidin (hep2), piscidin (pisc) in meagre (Argyrosomus regius). A phylogenetic analysis of the expressed sequences obtained shows the defensin isoform forms a clade with the other members of the beta class of this family, hepcidin corresponds to hepcidin 2, and piscidin corresponds to class I of its respective family. Gene expression profiles of AMPs was investigated, by means of quantification of mRNA in nine development stages, from 8 days post-hatching (dph) to accomplishment of juvenile form (120 dph). During development it was demonstrated defb, hep2, pisc were expressed in all stages of larval development and in juvenile tissues (kidney, spleen gut and gill). Moreover, expression patterns suggest the expression levels of theses AMPs are influenced by live prey (rotifer, Artemia) and first intake of commercial diet. Induction experiments in vivo (24 h) and in vitro (4, 12, 24 h) with PAMPs (LPS, poly (I:C), β-glucan) revealed significant changes in gene expression of the three AMP genes, in kidney, spleen, gut and gill. However, expression profiles differed in magnitude and time course response. defb expression shows a similar trend in vivo and in vitro in kidney at 24 h after LPS and β-glucan stimulation. The hep2 expression levels were up-regulated upon β-glucan challenge in vivo, more in gut and gills than kidney, while in vitro hep2 expression was up-regulated in kidney cells by LPS, poly (I:C), β-glucan (4 h). pisc expression was up-regulated in kidney cells, splenocytes by β-glucan, but in gill cells by poly (I:C) and β-glucan in vivo. However, pisc expression was upregulated in kidney cells by β-glucan and gill cells by LPS at 4 post-stimulation in vitro. These data suggest that AMPs play an important role in defense against pathogens, with each AMP having differing efficacies against specific types of microorganisms, although follow-up studies focusing on the biological activities in fish are needed.

Biological activity of peptides purified from fish skin hydrolysates

“…AMPS can be majorly divided into different families which include defensin, parasin, cathelicidin and hepcidin, and piscidin. These AMP families are species-specific, with piscidin being unique to teleost fish (Campoverde et al 2017). Table 3 outlines the specific MEC and MIC values for fish skin peptides with antimicrobial activity along with their sequences.…”

Molecular characterization and expression analysis of hepc1 and hepc2 in three tilapia species collected from Lake Manzala

“…It has been found that the two hepcidin peptides identified in teleost fish show a degree of sub functionalization of its functions, where hepcidin 1 (HAMP1) more implicated in iron metabolism regulation and hepcidin 2 (HAMP2) mainly performing an antimicrobial role (Neves et al 2015). The AMP production go through a main pathway by the recognition of pathogen-associated molecular patterns (PAMPs) through receptors (PRRs), such as Toll-like receptors (TLRs), exciting a cascade of intracellular signaling involving MyD88, TRAF6, IRAK1, and IKK that promotes the activation and translocation of NF-kB to the nucleus where it transcriptionally stimulates AMPs and other effector molecules (Campoverdea et al 2017).…”

Description of epithelial granular cell in catshark spiral intestine: Immunohistochemistry and ultrastructure

“…Antimicrobial peptides (AMPs) are small size molecules (less than 100 aa) with antimicrobial activity, belonging to the innate immune system in teleosts (Campoverde et al, ; Casadei et al, ; Secombes & Wang, ; Zou, Mercier, Koussounadis, & Secombes, ). Many cells in the lining epithelial surface, such as in gill, skin, and gut, secrete AMPs (Campoverde et al, ; Secombes & Wang, ; Zou et al, ). After being challenged with the Gram negative Yersinia ruckeri , the expression of the AMP ß‐defensins (BD‐3 and BD‐4) showed a significant increase in the blood of rainbow trout (Monte, Urquhart, Secombes, & Collet, ).…”

“…After being challenged with the Gram negative Yersinia ruckeri , the expression of the AMP ß‐defensins (BD‐3 and BD‐4) showed a significant increase in the blood of rainbow trout (Monte, Urquhart, Secombes, & Collet, ). Recently, several novel teleost ß‐defensin s were identified and detected by RT‐PCR from rainbow trout (Casadei et al, ), zebrafish (Zou et al, ), and meagre (Campoverde et al, ). Defensins are important peptides with immunomodulatory function and represent an important linking factor between innate and adaptive immunity (Campoverde et al, ).…”

“…Recently, several novel teleost ß‐defensin s were identified and detected by RT‐PCR from rainbow trout (Casadei et al, ), zebrafish (Zou et al, ), and meagre (Campoverde et al, ). Defensins are important peptides with immunomodulatory function and represent an important linking factor between innate and adaptive immunity (Campoverde et al, ).…”