Abstract
Host immune function can contribute to numerous ecological/evolutionary processes. Ecoimmunological studies, however, typically use one/few phenotypic immune assays and thus do not consider the complexity of the immune system. Therefore, “omics” resources that allow quantifying immune activity across multiple pathways are needed for ecoimmunological models. We applied short-read based RNAseq (Illumina NextSeq 500, PE-81) to characterise transcriptome profiles of a multipurpose model species Lymnaea stagnalis (Gastropoda). We used a genetically diverse snail stock and exposed individuals to immune elicitors (injury, bacterial/trematode pathogens) and changes in environmental conditions that can alter immune activity (temperature, food availability). Immune defence factors identified in the de novo assembly indicated uniform aspects of molluscan immunity: pathogen-recognition receptors (PRR) and lectins activate Toll-like receptor (TLR) pathway and cytokines that regulate cellular and humoral defences. However, also apparent differences to other taxa were detected (i.e., modest numbers of antimicrobial peptides and fibrinogen related proteins). Identified factors also indicate that several of them might contribute to the phenotypic immune assays used on this species. Experimental treatments revealed factors from non-self recognition (lectins) and signalling (TLR pathway, cytokines) to effectors [e.g., antibacterial proteins, phenoloxidase (PO) enzymes] whose gene expression depended on immune activations and environmental conditions, as well as components of snail physiology/metabolism that may drive these effects. Interestingly, gene expression of many factors (e.g., PRR, lectins, cytokines, PO enzymes, antibacterial proteins) showed high among-individual variation. Such factors are important to include in ecoimmunological research because they may explain among-individual differences in parasite resistance and fitness in natural populations.
Competing Interest Statement
The authors have declared no competing interest.
- ADH
- alcohol dehydrogenase
- AIF
- apoptosis-inducing factor
- AMP
- antimicrobial peptide
- CAT
- catalase
- DUOX
- dual oxidase
- DUOXA
- oxidase maturation factor
- ERR
- estrogen-related receptor
- FAIM1
- Fas apoptotic inhibitory molecule 1
- FBG
- fibrinogen-like domain
- FREP
- fibrinogen-related protein
- GNBP
- Gram-negative bacteria binding-protein
- GST
- glutathione S-transferase
- HSF
- heat shock factor
- HSP70
- 70 kilodalton heat shock protein
- HSP90
- 90 kilodalton heat shock protein
- HTRA2
- serine protease
- IAP
- inhibitor of apoptosis proteins
- IgSF
- immunoglobulin superfamily
- IKK
- inhibitor of NF-κB kinase
- IL-17
- interleukin 17A
- IκB
- inhibitor of nuclear factor-κB
- LAAO
- L-amino acid oxidase
- LBP/BPI
- lipopolysaccharide-binding protein/bactericidal permeability-increasing protein
- L-dopa
- l-3,4-dihydroxyphenylalanine
- LITAF
- PS-induced TNF-α factor
- LRR
- leucine-rich repeat
- MIF
- macrophage migration inhibitory factor
- MPEG
- macrophage expressed gene
- MyD88
- myeloid differentiation primary response protein 88
- NADPH
- nicotinamide adenine dinucleotide phosphate
- Nemo
- NF-B essential modulator
- NF-B
- nuclear factor B
- NF-κB
- nuclear factor-κB
- NOS
- nitric oxide synthase
- NOX
- NADPH-oxidase
- ORF
- open reading frame
- PARP
- poly (ADP-ribose) polymerase
- PC
- principal component
- PCA
- principal component analysis
- PGRP
- peptidoglycan recognition protein
- PO
- phenoloxidase
- PP1
- protein phosphatase
- PRR
- pathogen-recognition receptors
- RXR
- retinoid acid receptor
- SARM
- sterile alpha and armadillo motif-containing protein
- SOD and MnSOD
- superoxidase dismutases
- TAB
- TAK1 binding protein
- TAK1
- transforming growth factor β-activated kinase-1
- TIR
- Toll-interleukin receptor
- TLR
- Toll-like receptor
- TNF
- tumor necrosis factor
- TPM
- transcripts per million
- TRAF
- tumor necrosis factor receptor-associated factor
- TRF
- TRAF-like protein
- VIgLs
- variable immunoglobulin and lectin-domain-containing molecules.