Viral and bacterial septicaemic infections modulate the expression of PACAP splicing variants and VIP/PACAP receptors in brown trout immune organs.
Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) and PACAP-Related Peptide (PRP) are structurally similar peptides encoded in the same transcripts. Their transcription has been detected not only in the brain but also in a wide range of peripheral tissues, even including organs of the immune system. PACAP exerts pleiotropic activities through G-protein coupled membrane receptors: the PACAP-specific PAC-1 and the VPAC-1 and VPAC-2 receptors that exhibit similar affinities for the Vasoactive Intestinal Peptide (VIP) and PACAP. Recent findings added PACAP and its receptors to the growing list of mediators that allow cross-talk between the nervous, endocrine and immune systems in fish. In this study the expression of genes encoding for PACAP and PRP, as well as VIP/PACAP receptors was studied in laboratory-reared brown trout (Salmo trutta) after septicaemic infections. Respectively Viral Haemorrhagic Septicaemia Virus (VHSV-Ia) or the Gram-negative bacterium Yersinia ruckeri (ser. O1 - biot. 2) were used in infection challenges. Kidney and spleen, the teleost main lymphopoietic organs, were sampled during the first two weeks post-infection. RT-qPCR analysis assessed specific pathogens burden and gene expression levels. PACAP and PRP transcription in each organ was positively correlated to the respective pathogen burden, assessed targeting the VHSV-glycoprotein or Y. ruckeri 16S rRNA. Results showed as the transcription of PACAP splicing variants and VIP/PACAP receptors is modulated in these organs during an acute viral and bacterial septicaemic infections in brown trout. These gene expression results provide clues as to how the PACAP system is modulated in fish, confirming an involvement during active immune responses elicited by both viral and bacterial aetiological agents. However, further experimental evidence is still required to fully elucidate and characterize the role of PACAP and PRP for an efficient immune response against pathogens.
Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Scotland, UK; CEFAS Weymouth Laboratory, Weymouth, England, UK.
Bartolomeo
B
Gorgoglione
Aquatic Biotechnology Project, Centre for Genetic Engineering and Biotechnology, Havana, Cuba.
Yamila
Y
Carpio
Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Scotland, UK.
Christopher J
CJ
Secombes
CEFAS Weymouth Laboratory, Weymouth, England, UK.
Nick G H
NG
Taylor
Aquatic Biotechnology Project, Centre for Genetic Engineering and Biotechnology, Havana, Cuba.
Juana María
JM
Lugo
Aquatic Biotechnology Project, Centre for Genetic Engineering and Biotechnology, Havana, Cuba. Electronic address: mpabloe5@yahoo.com.
Mario Pablo
MP
Estrada
D000818:Animals; D005393:Fish Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D031941:Hemorrhagic Septicemia, Viral / Q000235:genetics / Q000276:immunology* / Q000821:virology; D007668:Kidney / Q000382:microbiology / Q000821:virology; D008969:Molecular Sequence Data; D029141:Novirhabdovirus / Q000502:physiology; D010446:Peptide Fragments / Q000235:genetics* / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000235:genetics* / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D018005:Receptors, Vasoactive Intestinal Peptide / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000382:microbiology / Q000821:virology; D059467:Transcriptome; D014337:Trout; D015007:Yersinia / Q000502:physiology; D015009:Yersinia Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*
D029941:Fish Proteins; C108999:PACAP-related peptide; D010446:Peptide Fragments; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011498:Protein Precursors; D018005:Receptors, Vasoactive Intestinal Peptide
ERM; Functional cross-talk; PACAP; PRP; Salmo trutta; VHS; VIP/PACAP receptors