title: Molecular and functional characterization of caspase-8 from the big-belly seahorse (Hippocampus abdominalis).
abstract: Apoptosis is a physiological process that can also participate in host immune defense mechanisms, including tumor growth suppression along with homeostasis and maturation of immune cells. Caspases are known to be involved in cellular apoptotic signaling; among them, caspase-8 plays an important role in the initiation phase of the apoptotic death cascade. In the current study, we molecularly characterized a caspase-8 homolog (designated as HaCasp-8) from Hippocampus abdominalis. The HaCasp-8 gene harbors a 1476 bp open reading frame (ORF) that codes for a protein of 492 amino acids (aa) with a predicted molecular mass of 55 kDa. HaCasp-8 houses the typical domain architecture of known initiator caspases, including the death effector domain and the carboxyl-terminal catalytic domain. As expected, phylogenetic analysis reflected a closer evolutionary relationship of HaCasp-8 with its teleostean similitudes. The results of our qPCR assays confirmed the ubiquitous expression of HaCasp-8 in physiologically important tissues examined, with pronounced expression levels in ovary tissues, followed by blood cells. HaCasp-8 expression at the mRNA level was found to be significantly modulated by lipopolysaccharide, polyinosinic:polycytidylic acid, Streptococcus iniae, and Edwardsiella tarda injection. Overexpression of HaCasp-8 could trigger a significant level of cell death in HEK293T cells, suggesting its putative role in cell death. Taken together, our findings suggest that HaCasp-8 is an important component in the caspase cascade, and its expression can be significantly modulated under pathogen stress conditions in the big-belly seahorse.
authors.affiliation: Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea.
authors.forename: Minyoung
authors.initials: M
authors.lastname: Oh
authors.affiliation: Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Department of Zoology, University of Sri Jayewardenepura, Gangodawila, Nugegoda, 10250, Sri Lanka.
authors.forename: Don Anushka Sandaruwan
authors.initials: DAS
authors.lastname: Elvitigala
authors.affiliation: Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea.
authors.forename: S D N K
authors.initials: SDNK
authors.lastname: Bathige
authors.affiliation: Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea.
authors.forename: Seongdo
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea. Electronic address: mj.kim.lucky@gmail.com.
authors.forename: Myoung-Jin
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Development Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea. Electronic address: jehee@jejunu.ac.kr.
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D053181:Caspase 8 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D020609:Edwardsiella tarda / Q000502:physiology; D004756:Enterobacteriaceae Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D005260:Female; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000494:pharmacology*; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D016415:Sequence Alignment / Q000662:veterinary; D023701:Smegmamorpha; D000070058:Streptococcus iniae / Q000502:physiology; D014735:Vibrio Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D008070:Lipopolysaccharides; D000069452:Pathogen-Associated Molecular Pattern Molecules; D053181:Caspase 8; D011070:Poly I-C
keywords: Big-belly seahorse; Caspase-8; Immune challenge; mRNA expression