Proinflammatory Caspase A Activation and an Antiviral State Are Induced by a Zebrafish Perforin after Possible Cellular and Functional Diversification from a Myeloid Ancestor

Abstract

In mammals, perforins play a central role in the granule-dependent cell death induced by natural killer T cells and cytotoxic T lymphocytes, and participate both in the defense against virus-infected and neoplastic cells and in the recognition of nonself molecules by the immune system. Little is known about fish perforin genes. We examined the zebrafish with the aim of increasing our knowledge about the role of perforins. We characterized 6 perforin genes in the zebrafish genome, and we studied them at the evolutionary level in combination with expression patterns in several tissues and cell populations, during both larval development and in the course of a viral infection. Our results suggest the specialization of different cell types in the production of perforins. Moreover, functional diversification during the evolution of these molecules could be inferred from this study. In particular, one of the genes, prf19b, which is mainly produced by myeloid cells, seemed to be involved in antiviral defense, conferring protection after an in vivo infection.

Molecular characterization of three novel perforins in common carp (Cyprinus carpio L.) and their expression patterns during larvae ontogeny and in response to immune challenges

“…Similar to the previous report that under basal conditions 6 zebrafish perforin genes were all expressed in the liver, spleen, kidney, intestine, gill and muscle [ 22 ]. Each Cc PRF gene was expressed in the nine analysed tissues (the liver, spleen, head kidney, foregut, hindgut, gill, skin, brain and muscle) (Fig.…”

“…6 and 8a, b ). However, in contrast to SVCV, polyI:C was not able to increase mRNA levels of zebrafish perforins within 24 hpi, with the exception of PRF1.6, in the kidney [ 22 ], which was consistent with the in vivo results in common carp. Additionally, rock bream perforin gene was not induced by virus shortly post infection, until a few days later [ 20 , 21 ].…”

“…Additionally, in the zebrafish, it was demonstrated that immune system of the larvae was completely mature between 4 and 6 weeks post fertilization [ 41 ]. In accordance with this time period, during the larvae ontogeny of zebrafish, expression peaks were observed around the fourth week of development (23 dpf and 29 dpf) in several perforin genes [ 22 ]. Similarly, in the early development stages of common carp larvae, in spite of differential expression patterns for the three Cc PRFs, they showed a common expression peak at 22 dph (Fig.…”

“…In the rainbow trout RTS11 cell line, infection with viral hemorrhagic septicaemia virus (VHSV) up-regulated perforin gene expression [ 50 ]. In the zebrafish kidney, in vivo stimulation with spring viremia of carp virus (SVCV) increased mRNA levels of multiple perforins including PRF1.1, 1.3, 1.5, 1.6 and 1.9 at 6 hpi, and polyI:C induced PRF1.6 expression at 3 hpi [ 22 ]. Similarly, in common carp, mRNA levels of the three Cc PRFs were significantly up-regulated in response to polyI:C in vivo and in vitro (Figs.…”

“…In humans and mice, perforin is a single-copy gene, and presently its immunological function has been well studied. In teleosts, until now, the perforin genes have been characterized in 6 species, including Japanese flounder ( Paralichtys olivaceus ) [ 15 , 16 ], channel catfish ( Ictalurus punctatus ) [ 17 ], rainbow trout ( Oncorhynchus mykiss ) [ 18 ], ginbuna crucian carp ( Carassius auratus langsdorfii ) [ 19 ], rock bream ( Oplegnathus fasciatus ) [ 20 , 21 ] and zebrafish ( Danio rerio ) [ 22 ]. Moreover, different with humans and mice, there are more than one perforin genes in fish genomes [ 19 , 22 ], although only one isoform was reported in some teleosts to date [ 16 – 18 , 20 ].…”