title: Apolipoprotein A-I in Labeo rohita: Cloning and functional characterisation reveal its broad spectrum antimicrobial property, and indicate significant role during ectoparasitic infection.
abstract: Apolipoprotein A-I (ApoA-I) is the most abundant and multifunctional high-density lipoprotein (HDL) having a major role in lipid transport and potent antimicrobial activity against a wide range of microbes. In this study, a complete CDS of 771 bp of Labeo rohita (rohu) ApoA-I (LrApoA-I) encoding a protein of 256 amino acids was amplified, cloned and sequenced. Tissue specific transcription analysis of LrApoA-I revealed its expression in a wide range of tissues, with a very high level of expression in liver and spleen. Ontogenic study of LrApoA-I expression showed presence of transcripts in milt and 3 h post-fertilization onwards in the larvae. The expression kinetics of LrApoA-I was studied upon infection with three different types of pathogens to elucidate its functional significance. Its expression was found to be up-regulated in the anterior kidney of L. rohita post-infection with Aeromonas hydrophila. Similarly following poly I:C (poly inosinic:cytidylic) stimulation, the transcript levels increased in both the anterior kidney and liver tissues. Significant up-regulation of LrApoA-I expression was observed in skin, mucous, liver and anterior kidney of the fish challenged with the ectoparasite Argulus siamensis. Immunomodulatory effect of recombinant LrApoA-I (rApoA-I) produced in Escherichia coli was demonstrated against A. hydrophila challenge in vivo. L. rohita administered with rApoA-I at a dose of 100 μg exhibited significantly higher protection (∼55%) upon challenge with A. hydrophila 12 h post-administration of the protein, in comparison to that observed in control group, along with higher level of expression of immune-related genes. The heightened expression of ApoA-I observed post-infection reflected its involvement in immune responses against a wide range of infections including bacterial, viral as well as parasitic pathogens. Our results also suggest the possibility of using rApoA-I as an immunostimulant, particularly rendering protection against A. hydrophila.
authors.affiliation: Fish Health Management Division, ICAR-Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, 751002, India.
authors.forename: Amruta
authors.initials: A
authors.lastname: Mohapatra
authors.affiliation: Gene Regulation Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110 067, India.
authors.forename: Sweta
authors.initials: S
authors.lastname: Karan
authors.affiliation: Fish Health Management Division, ICAR-Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, 751002, India.
authors.forename: Banya
authors.initials: B
authors.lastname: Kar
authors.affiliation: Gene Regulation Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
authors.forename: L C
authors.initials: LC
authors.lastname: Garg
authors.affiliation: Gene Regulation Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110 067, India.
authors.forename: A
authors.initials: A
authors.lastname: Dixit
authors.affiliation: Fish Health Management Division, ICAR-Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, 751002, India. Electronic address: pksahoo1@hotmail.com.
authors.forename: P K
authors.initials: PK
authors.lastname: Sahoo
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D016632:Apolipoprotein A-I / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D033341:Arguloida / Q000502:physiology; D003001:Cloning, Molecular; D003530:Cyprinidae; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004478:Ectoparasitic Infestations / Q000235:genetics / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D005393:Fish Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology / Q000469:parasitology; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D010802:Phylogeny; D011070:Poly I-C / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment / Q000662:veterinary
chemical_list: D016632:Apolipoprotein A-I; D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D011070:Poly I-C
keywords: Aeromonas hydrophila; Antimicrobial property; Apolipoprotein A-I; Argulus siamensis; Labeo rohita; Poly I:C