Molecular characterization and gene expression data of liver expressed antimicrobial Peptide-2 (LEAP-2) isolated from rock bream (Oplegnathus fasciatus)

Abstract

Antimicrobial peptides (AMPs) are known to play a role as a first line of defence against microbial invasion. Liver Expressed Antimicrobial Peptides-2 (LEAP-2) is one of the AMPs. LEAP-2 includes four highly conserved cysteine residues and belongs to a cysteine-rich peptides group. We identified and characterized the molecular properties of LEAP-2 in rock bream. The expression levels of rock bream LEAP-2 (RbLEAP-2) in the 12 different tissues of healthy fish and the RbLEAP-2 expression pattern after infections with Edwardsiella piscicida (E. piscicida), Streptococcus iniae (S. iniae) and red seabream iridovirus (RSIV) were examined. This data provide that RbLEAP-2 plays an important role in innate immunity when rock bream is infected with a pathogen.

Structure–activity relationships of the intramolecular disulphide bonds in LEAP2, an antimicrobial peptide from Acrossocheilus fasciatus

“…Notably, LEAP2 expression in T. ovatus is high in the liver, spleen, head kidney, and gills [ 9 ], whereas in O. mykiss , LEAP2A, and LEAP2B are constitutively expressed only in the liver [ 8 ]. Our investigation revealed that following A. hydrophila infection, A. fasciatus LEAP2 expression is upregulated in all examined tissues, consistent with previous studies on other fish species [ 8 – 12 , 14 , 16 , 18 , 19 , 22 , 23 ]. For example, in B. pectinirostris , the liver, spleen, kidney, and gills exhibit an immediate increase in LEAP2 expression upon E. tarda infection [ 19 ].…”

“…As in mammals, LEAP2 has also been detected in various fishes [4], birds [5], reptiles [6], and even amphibians [7]. Initially, the identification of LEAP2 was limited to Oncorhynchus mykiss [8], however, subsequent research efforts have led to its isolation and characterization in a diverse range of fish species [9][10][11][12][13][14][15][16][17][18]. In contrast to the singular LEAP2 homologue present in mammals, certain fish species, such as O. mykiss, Larimichthys crocea, and Cyprinus carpio, have multiple homologues, typically categorised as LEAP2A, LEAP2B, and LEAP2C [8,16,18].…”

“…Conversely, in Larimichthys crocea, transcript levels in the liver are significantly lower than those in the intestine [16]. The expression of LEAP2 exhibits a robust correlation with the immune response of fish in relation to pathogenic organisms [9][10][11][12]19]. For instance, in Boleophthalmus pectinirostris, liver, spleen, kidney, and gill LEAP2 expression is immediately upregulated upon infection with Edwardsiella tarda [19].…”

“…Fish LEAP2 has antibacterial activity against both gram-positive and gram-negative bacteria [9][10][11][12]19]. For example, purified recombinant T. ovatus LEAP2 exerts significant inhibitory effects on E. tarda and Streptococcus agalactiae in vitro growth.…”

Marine Organisms as a Rich Source of Biologically Active Peptides

“…Liver Expressed Antimicrobial Peptides-2 (LEAP-2) is an AMP that belongs to a group of peptides rich in cysteine. Hwang et al (2019) identified and characterized Cheung et al (2015).…”