Inflammatory responses in primary muscle cell cultures in Atlantic salmon (Salmo salar)

Abstract

BackgroundThe relationship between fish health and muscle growth is critical for continued expansion of the aquaculture industry. The effect of immune stimulation on the expression of genes related to the energy balance of fish is poorly understood. In mammals immune stimulation results in major transcriptional changes in muscle, potentially to allow a reallocation of amino acids for use in the immune response and energy homeostasis. The aim of this study was to investigate the effects of immune stimulation on fish muscle gene expression.ResultsAtlantic salmon (Salmo salar) primary muscle cell cultures were stimulated with recombinant (r)IL-1β, a major proinflammatory cytokine, for 24 h in order to simulate an acute immune response. The transcriptomic response was determined by RNA hybridization to a 4 × 44 K Agilent Atlantic salmon microarray platform. The rIL-1β stimulation induced the expression of genes related to both the innate and adaptive immune systems. In addition there were highly significant changes in the expression of genes related to regulation of the cell cycle, growth/structural proteins, proteolysis and lipid metabolism. Of interest were a number of IGF binding proteins that were differentially expressed, which may demonstrate cross talk between the growth and immune systems.ConclusionWe show rIL-1β modulates the expression of not only immune related genes, but also that of genes involved in processes related to growth and metabolism. Co-stimulation of muscle cells with both rIGF-I and rIL-1β demonstrates cross talk between these pathways providing potential avenues for further research. This study highlights the potential negative effects of inflammation on muscle protein deposition and growth in fish and extends our understanding of energy allocation in ectothermic animals.

Polysaccharides from marine macroalga, Padina gymnospora improve the nonspecific and specific immune responses of Cyprinus carpio and protect it from different pathogens

“…Interleukin-1 beta (IL-1β) is an important mediator of inflammatory response in fishes (Bo et al 2015) and innate immune mechanism (Pooley et al 2013). IL-1β as a defensive M A N U S C R I P T…”

Divergent regulation of insulin-like growth factor binding protein genes in cultured Atlantic salmon myotubes under different models of catabolism and anabolism

“…For example, glucocorticoids such as the cortisol-analogue dexamethasone, increase the transcription of murf1, mafbx and autophagy genes, while inhibiting protein synthesis by blocking mTor function (Braun and Marks, 2015). In addition, cytokines, such as Tnfα and IL-1β increase the transcription of E3-ubiquitin ligases, including murf1 via Nfκβ pathways (Glass, 2005;Pooley et al, 2013). Finally, fasting stimulates protein degradation by repressing Akt activation, leading to FoxO-mediated transcriptional upregulation of both E3-ubiquitin ligases and macro-autophagy genes (e.g.…”

Growth hormone transgenesis disrupts immune function in muscle of coho salmon (Oncorhynchus kisutch) impacting cross-talk with growth systems

“…Bonneaud et al 2003; Lochmiller and Deerenberg, 2000; Cutrera et al 2010). Recent studies in fish have revealed that the expression of certain genes from the IGF system is altered during the host defence response to bacterial and viral infections, consistent with a downregulation of growth and reallocation of resources towards immune function (Pooley et al, 2013; Alzaid et al, 2016a, 2016b). Until now, little consideration has been given to the regulation of growth pathways following immune stimulation in skeletal muscle, which is the most important target tissue for energetic investment and storage.…”

“…IGFBP-3: Foulstone et al 2003; IGFBP-5: Ren et al 2008) and inhibitory (e.g. IGFBP-2: Swiderski et al 2016; IGFBP-6: Pooley et al 2013) impacts on muscle growth. Hence, it is difficult to predict the effects that downregulation of multiple IGFBP subtypes will have in the GH transgenics, both in terms of muscle growth, but also several other metabolic phenotypes known to be regulated by this protein family (Jones and Clemmons, 1995).…”

“…What little is known about the regulation of GH and IGF pathway genes in teleost muscle following immune stimulation has come from in vitro work. Treatment of Atlantic salmon muscle cell cultures with the pro-inflammatory cytokine IL-1β resulted in up-regulation of an IGFBP-6 subtype, suggested to represses IGF signalling (Pooley et al, 2013; Heidari et al, 2015). However, in a separate study, treatment of differentiated Atlantic salmon myotubes with the same cytokine resulted in limited expression changes in IGF system genes, despite the verified presence of muscle fibre atrophy (Garcia de la serrana et al, 2017).…”