Cortisol metabolism in carp macrophages : a role for macrophage-derived cortisol in M1/M2 polarization

Macrophages are crucial not only for initiation of inflammation and pathogen eradication (classically polarized M1 macrophages), but also for inflammation inhibition and tissue regeneration (alternatively polarized M2 macrophages). Their polarization toward the M1 population occurs under the influence of interferon-γ + lipopolysaccharide (IFN-γ + LPS), while alternatively polarized M2 macrophages evolve upon, e.g., interlukin 4 (IL-4) or cortisol stimulation. This in vitro study focused on a possible role for macrophage-derived cortisol in M1/M2 polarization in common carp. We studied the expression of molecules involved in cortisol synthesis/conversion from and to cortisone like 11β-hydroxysteroid dehydrogenase type 2 and 3. (11β-HSD2 and 3) and 11β-hydroxylase (CYP11b), as well as the expression of glucocorticoid receptors (GRs) and proliferator-activated receptor gamma (PPARγ) in M1 and M2 macrophages. Lastly, we analyzed how inhibition of these molecules affect macrophage polarization. In M1 cells, upregulation of gene expression of GRs and 11β-HSD3 was found, while, in M2 macrophages, expression of 11β-hsd2 was upregulated. Moreover, blocking of cortisol synthesis/conversion and GRs or PPARγ induced changes in expression of anti-inflammatory interleukin 10 (IL-10). Consequently, our data show that carp monocytes/macrophages can convert cortisol. The results strongly suggest that cortisol, via intracrine interaction with GRs, is important for IL-10-dependent control of the activity of macrophages and for the regulation of M1/M2 polarization to finally determine the outcome of an infection

Trypanosomiasis-Induced Th17-Like Immune Responses in Carp

Background - In mammalian vertebrates, the cytokine interleukin (IL)-12 consists of a heterodimer between p35 and p40 subunits whereas interleukin-23 is formed by a heterodimer between p19 and p40 subunits. During an immune response, the balance between IL-12 and IL-23 can depend on the nature of the pathogen associated molecular pattern (PAMP) recognized by, for example TLR2, leading to a preferential production of IL-23. IL-23 production promotes a Th17-mediated immune response characterized by the production of IL-17A/F and several chemokines, important for neutrophil recruitment and activation. For the cold blooded vertebrate common carp, only the IL-12 subunits have been described so far. Methodology/Principal Findings - Common carp is the natural host of two protozoan parasites: Trypanoplasma borreli and Trypanosoma carassii. We found that these parasites negatively affect p35 and p40a gene expression in carp. Transfection studies of HEK293 and carp macrophages show that T. carassii-derived PAMPs are agonists of carp TLR2, promoting p19 and p40c gene expression. The two protozoan parasites induce different immune responses as assessed by gene expression and histological studies. During T. carassii infections, in particular, we observed a propensity to induce p19 and p40c gene expression, suggestive of the formation of IL-23. Infections with T. borreli and T. carassii lead to an increase of IFN-¿2 gene expression whereas IL-17A/F2 gene expression was only observed during T. carasssii infections. The moderate increase in the number of splenic macrophages during T. borreli infection contrasts the marked increase in the number of splenic neutrophilic granulocytes during T. carassii infection, along with an increased gene expression of metalloproteinase-9 and chemokines. Conclusion/Significance - This is the first study that provides evidence for a Th17-like immune response in fish in response to infection with a protozoan parasit

Time and concentration dependency of MacroGard® induced apoptosis

In previous studies an effect of β-glucan on apoptosis in fish was noted and in this investigation we determine the time and concentration dependency of this effect. Primary cell cultures of pronephric carp cells were incubated for 6, 24, 48 h with various concentrations ranging from 0 to 1000 μg/ml of MacroGard® β-glucan. Apoptosis was monitored via acridine orange staining. Results indicate a clear effect of time and concentration on the induction of apoptosis in vitro, with only concentration ≥500 μg/ml causing significantly higher percentages of apoptotic cells. Apoptosis was detected after 6 h. This concentration dependent effect has to be considered when studying apoptosis in relation to immunostimulation

Peritoneal cavity phagocytes from the teleost sea bass express a glucocorticoid receptor (cloned and sequenced) involved in genomic modulation of the in vitro chemiluminescence response to zymosan

Abstract To gain further insight into the role of cortisol in Wsh innate immune responses, we cloned and sequenced a 2592 bp cDNA from sea bass (Dicentrarchus labrax) peritoneal leukocytes (PCLs) encoding a glucocorticoid receptor (DlGR1). The deduced aminoacid sequence displayed that DlGR1 belong to a multigenic family of steroid hormone receptors, and exhibited high homology (80%) to the Burton’s mouth breeder (Haplochromis burtoni) HbGR1. The DlGR1 functional domains presented homologies with those of several vertebrate species. In situ hybridization assay revealed that DlGR1 was expressed in macrophages and neutrophils from the peritoneal cavity. Since in a previous paper, sea bass PCL chemiluminescence response (CL) has been related to increased respiratory burst of phagocytes stimulated with zymosan, PCLs, preincubated in vitro with cortisol at various concentrations, were assayed for their CL response. Dose-dependent cortisol inhibitory eVects, and signiWcant competitive activity of a low concentration of mifepristone (RU486), a glucocorticoid-receptor blocker, supported that cortisol–GR interaction was involved in modulating CL response via a genomic pathway. Results also indicated that cortisol could be eVective through an additional not-genomic way, and showed that high doses of RU486 exerted an inhibitory eVect on PCL chemiluminescence activity. © 2006 Elsevier Inc. All rights reserved

Incomplete posttranslational prohormone modifications in hyperactive neuroendocrine cells

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The Use of Dietary Additives in Fish Stress Mitigation: Comparative Endocrine and Physiological Responses

In the last years, studies on stress attenuation in fish have progressively grown. This is mainly due to the interest of institutions, producers, aquarists and consumers in improving the welfare of farmed fish. In addition to the development of new technologies to improve environmental conditions of cultured fish, the inclusion of beneficial additives in the daily meal in order to mitigate the stress response to typical stressors (netting, overcrowding, handling, etc.) has been an important research topic. Fish are a highly diverse paraphyletic group (over 27,000 species) though teleost infraclass include around 96% of fish species. Since those species are distributed world-wide, a high number of different habitats and vital requirements exist, including a wide range of environmental conditions determining specifically the stress response. Although the generalized endocrine response to stress (based on the release of catecholamines and corticosteroids) is detectable and therefore provides essential information, a high diversity of physiological effects have been described depending on species. Moreover, recent omics techniques have provided a powerful tool for detecting specific differences regarding the stress response. For instance, for transcriptomic approaches, the gene expression of neuropeptides and other proteins acting as hormonal precursors during stress has been assessed in some fish species. The use of different additives in fish diets to mitigate stress responses has been deeply studied. Besides the species factor, the additive type also plays a pivotal role in the differentiation of the stress response. In the literature, several types of feed supplements in different species have been assayed, deriving in a series of physiological responses which have not focused exclusively on the stress system. Immunological, nutritional and metabolic changes have been reported in these experiments, always associated to endocrine processes. The biochemical nature and physiological functionality of those feed additives strongly affect the stress response and, in fact, these can act as neurotransmitters or hormone precursors, energy substrates, cofactors and other essential elements, implyingmulti-systematic and multi-organic responses. In this review, the different physiological responses among fish species fed stress-attenuating diets based on biomolecules and minerals have been assessed, focusing on the endocrine regulation and its physiological effects

Dietary Tryptophan Induces Opposite Health-Related Responses in the Senegalese Sole (Solea senegalensis) Reared at Low or High Stocking Densities With Implications in Disease Resistance

High rearing densities are typical conditions of both inland and onshore intensive aquaculture units. Despite obvious drawbacks, this strategy is nonetheless used to increase production profits. Such conditions inflict stress on fish, reducing their ability to cope with disease, bringing producers to adopt therapeutic strategies. In an attempt to overcome deleterious effects of chronic stress, Senegalese sole, Solea senegalensis, held at low (LD) or high density (HD) were fed tryptophan-supplemented diets with final tryptophan content at two (TRP2) or four times (TRP4) the requirement level, as well as a control and non-supplemented diet (CTRL) for 38 days. Fish were sampled at the end of the feeding trial for evaluation of their immune status, and mortalities were recorded following intra-peritoneal infection with Photobacterium damselae subsp. piscicida. Blood was collected for analysis of the hematological profile and innate immune parameters in plasma. Pituitary and hypothalamus were sampled for the assessment of neuro-endocrine-related gene expression. During the feeding trial, fish fed TRP4 and held at LD conditions presented higher mortalities, whereas fish kept at HD seemed to benefit from this dietary treatment, as disease resistance increased over that of CTRL-fed fish. In accordance, cortisol level tended to be higher in fish fed both supplemented diets at LD compared to fish fed CTRL, but was lower in fish fed TRP4 than in those fed TRP2 under HD condition. Together with lower mRNA levels of proopiomelanocortin observed with both supplementation levels, these results suggest that higher levels of tryptophan might counteract stress-induced cortisol production, thereby rendering fish better prepared to cope with disease. Data regarding sole immune status showed no clear effects of tryptophan on leucocyte numbers, but TRP4-fed fish displayed inhibited alternative complement activity (ACH50) when held at LD, as opposed to their HD counterparts whose ACH50 was higher than that of CTRLfed fish. In conclusion, while dietary tryptophan supplementation might have harmful effects in control fish, it might prove to be a promising strategy to overcome chronic stress-induced disease susceptibility in farmed Senegalese sole

CXCL8 Chemokines in Teleost Fish: Two Lineages with Distinct Expression Profiles during Early Phases of Inflammation

Contains fulltext : 126584.pdf (publisher's version ) (Open Access

An overview of the reproductive cycle of cultured specimens of a potential candidate for Mediterranean aquaculture, Umbrina cirrosa

The shi drum (Umbrina cirrosa), belonging to the Sciaenidae family of fish (Nelson et al., 2016) has attracted attention as it is an excellent diversification species in Mediterranean aquaculture to combat the low prices of the most cultured species due to the appearance of new producing countries in the Mediterranean area. In this manuscript we describe for the first time the reproductive cycle of captive shi drum specimens that are able to spontaneously spawn in captivity. Our data show that spermatogenesis started in one year old shi drum spe- cimens, although the fish were not mature enough to complete the reproductive cycle. Thus, three year old specimens showed multiple spawns with around 65% of the eggs fertilized. In mature males, levels of 11-ke- totestosterone (11KT), testosterone (T) and progesterone (P) were detected in serum and gonad, while 17β- estradiol (E2) was only detected in gonad. Testicular levels of E2 and P suggest that these hormones might have a role in spawning and in the subsequent spermatogonial proliferation. In mature females, however, P and E2 were detected in serum and gonad, while T and 11KT were only detected in gonad. The pattern shown by P in the ovary indicates a link between this hormone and ovarian renewal and a delay in vitellogenesis, which would explain why the vitellogenic stage of shi drum is quite short. The level of T and 11KT in the ovary suggests a role in oocyte maturation and spawning. The differences observed between sexes in the prevalence of some infection and the important economic losses produced by some vertically transmitted pathogens; have increase the at- tention to the interactions between the immune and reproductive systems. In this study we observed differences between sexes in the protease and bactericide activity levels. Thus, this manuscript represents the most complete overview to date of the shi drum reproductive cycle.Versión del editor2,04