The aim of this article is to review the immunoregulatory actions of frog skin-derived peptides in order to assess their potential as candidates for immunomodulatory or anti-inflammatory therapy. ...Frog skin peptides with demonstrable immunomodulatory properties have been isolated from skin secretions of a range of species belonging to the families Alytidae, Ascaphidae, Discoglossidae, Leptodactylidae, Pipidae and Ranidae. Their effects upon production of inflammatory and immunoregulatory cytokines by target cells have been evaluated ex vivo and effects upon cytokine expression and immune cell activity have been studied in vivo by flow cytometry after injection into mice. The naturally-occurring peptides and/or their synthetic analogues show complex and variable actions on the production of proinflammatory (TNF-α, IL-1β, IL-12, IL-23, IL-8, IFN-γ and IL-17), pleiotropic (IL-4 and IL-6) and immunosuppressive (IL-10 and TGF-β) cytokines by peripheral and spleen cells, peritoneal cells and/or isolated macrophages. The effects of frenatin 2.1S include enhancement of the activation state and homing capacity of Th1-type lymphocytes and NK cells in the mouse peritoneal cavity, as well as the promotion of their tumoricidal capacities. Overall, the diverse effects of frog skin-derived peptides on the immune system indicate their potential for development into therapeutic agents.
Obesity-induced diabetes is associated with low-grade inflammation in adipose tissue and macrophage infiltration of islets. We show that ablation of galectin-3 (Gal-3), a galactoside-binding lectin, ...accelerates high-fat diet-induced obesity and diabetes. Obese LGALS3(-/-) mice have increased body weight, amount of total visceral adipose tissue (VAT), fasting blood glucose and insulin levels, homeostasis model assessment of insulin resistance, and markers of systemic inflammation compared with diet-matched wild-type (WT) animals. VAT of obese LGALS3(-/-) mice exhibited increased incidence of type 1 T and NKT lymphocytes and proinflammatory CD11c(+)CD11b(+) macrophages and decreased CD4(+)CD25(+)FoxP3(+) regulatory T cells and M2 macrophages. Pronounced mononuclear cell infiltrate, increased expression of NLRP3 inflammasome and interleukin-1β (IL-1β) in macrophages, and increased accumulation of advanced glycation end products (AGEs) and receptor for AGE (RAGE) expression were present in pancreatic islets of obese LGALS3(-/-) animals accompanied with elevated phosphorylated nuclear factor-κB (NF-κB) p65 and mature caspase-1 protein expression in pancreatic tissue and VAT. In vitro stimulation of LGALS3(-/-) peritoneal macrophages with lipopolysaccharide (LPS) and saturated fatty acid palmitate caused increased caspase-1-dependent IL-1β production and increased phosphorylation of NF-κB p65 compared with WT cells. Transfection of LGALS3(-/-) macrophages with NLRP3 small interfering RNA attenuated IL-1β production in response to palmitate and LPS plus palmitate. Obtained results suggest important protective roles for Gal-3 in obesity-induced inflammation and diabetes.
The importance of Galectin-3 (Gal-3) in obesity-associated liver pathology is incompletely defined. To dissect the role of Gal-3 in fibrotic nonalcoholic steatohepatitis (NASH), Gal-3-deficient ...(LGALS3(-/-)) and wild-type (LGALS3(+/+)) C57Bl/6 mice were placed on an obesogenic high fat diet (HFD, 60% kcal fat) or standard chow diet for 12 and 24 wks. Compared to WT mice, HFD-fed LGALS3(-/-) mice developed, in addition to increased visceral adiposity and diabetes, marked liver steatosis, which was accompanied with higher expression of hepatic PPAR-γ, Cd36, Abca-1 and FAS. However, as opposed to LGALS3(-/-) mice, hepatocellular damage, inflammation and fibrosis were more extensive in WT mice which had an elevated number of mature myeloid dendritic cells, proinflammatory CD11b(+)Ly6C(hi) monocytes/macrophages in liver, peripheral blood and bone marrow, and increased hepatic CCL2, F4/80, CD11c, TLR4, CD14, NLRP3 inflammasome, IL-1β and NADPH-oxidase enzymes mRNA expression. Thus, obesity-driven greater steatosis was uncoupled with attenuated fibrotic NASH in Gal-3-deficient mice. HFD-fed WT mice had a higher number of hepatocytes that strongly expressed IL-33 and hepatic CD11b(+)IL-13(+) cells, increased levels of IL-33 and IL-13 and up-regulated IL-33, ST2 and IL-13 mRNA in liver compared with LGALS3(-/-) mice. IL-33 failed to induce ST2 upregulation and IL-13 production by LGALS3(-/-) peritoneal macrophages in vitro. Administration of IL-33 in vivo enhanced liver fibrosis in HFD-fed mice in both genotypes, albeit to a significantly lower extent in LGALS3(-/-) mice, which was associated with less numerous hepatic IL-13-expressing CD11b(+) cells. The present study provides evidence of a novel role for Gal-3 in regulating IL-33-dependent liver fibrosis.
Dendritic cells (DCs) have important pathogenic role in the induction and progression of ulcerative colitis (UC), but their role in mesenchymal stem cells (MSCs)-mediated suppression of colon injury ...and inflammation is not revealed. By using dextran sodium sulfate (DSS)-induced colitis, a well-established murine model of UC, we examined effects of MSCs on phenotype and function of colon infiltrating DCs. Clinical, histological, immunophenotypic analysis and passive transfer of MSCs-primed DCs were used to evaluate capacity of MSC to suppress inflammatory phenotype of DCs in vivo. Additionally, DCs:MSCs interplay was also investigated in vitro, to confirmed in vivo obtained findings. Intraperitoneally administered MSCs (2 × 106) significantly reduced progression of DSS-induced colitis and reduced serum levels of inflammatory cytokines (IL-1β, IL-12, and IL-6). Passive transfer of in vivo MSCs-primed DCs reduced severity of colitis while passive transfer of MSCs-non-primed DCs aggravated DSS-induced colitis. Through the secretion of immunomodulatory Galectin 3, MSCs, in paracrine manner, down-regulated production of inflammatory cytokines in DCs and attenuated expression of co-stimulatory and major histocompatibility complex class II molecules on their membranes. Taken together, these results indicate that MSCs achieved their beneficial effects in DSS-induced colitis by suppressing inflammatory phenotype of DCs in Gal-3 dependent manner. Therapeutic targeting of DCs by MSCs should be explored in future studies as a useful approach for the treatment of UC.
•Gal-3 deficiency had anxiolytic effect in untreated adult mice.•Untreated Gal-3−/− mice had lower hippocampal IL-6, TNF-α, BDNF and GABA-AR.•Gal-3 deletion reduced anxiogenic effect of inflammation ...by preventing GABA-AR fall.•Gal-3 deletion prevented the LPS-induced rise of IL-6 and TNF-α and decline in BDNF.•Gal-3 shows dual effect on anxiety under basal conditions and after LPS.
Galectin-3 (Gal-3), a member of lectin family that binds to oligosaccharides, is involved in several biological processes, including maturation and function of nervous system. It had been reported that Gal-3 regulates oligodendrocytes differentiation and that Gal-3/Toll-like receptor-4 (TLR4) axis is involved in neuroinflammation. As both, central nervous system (CNS) maturation and neuroinflammation may affect behavior, the principle aim of this study was to examine the effects of Gal-3 gene deletion on behavior. Here we provide the evidence that Gal-3 deficiency shows clear anxiogenic effect in mature untreated animals (basal conditions). This was accompanied with lower interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) relative gene expression and hippocampal content, with no effect on TLR4 expression. Gal-3 deficiency was also accompanied with lower brain-derived neurotrophic factor (BDNF) relative gene expression and immunoreactivity in hippocampus (predominantly in CA1 region). Besides, the Gal-3 gene deletion resulted in attenuation of the hippocampal relative gene expression of GABA-A receptor subunits 2 and 5 (GABA-AR2S and GABA-AR5S), On the other hand, Gal-3 deficiency attenuates LPS-induced neuroinflammation. The anxiogenic effect of acute neuroinflammation was accompanied with increased hippocampal IL-6, TNF-α and TLR4 gene expression, as well as decreased gene and immunohistochemical BDNF expression in hippocampus, with significant decline in GABA-AR2S in wild type (WT) mice in comparison to basal conditions. Gal-3 gene deletion prevented the increase in IL-6, the decline in BDNF gene expression and immunoreactivity, and reduction in hippocampal GABA-AR2S, and therefore attenuated the anxiogenic effect of neuroinflammation. In summary, our data demonstrate that apparently opposite effects of Gal-3 deficiency on anxiety levels (anxiogenic effect under basal conditions and anxiolytic action during neuroinflammation) seem to be related to the shift in IL-6, TNF-α and hippocampal BDNF.
The increase of pro-inflammatory cytokines and oxidative stress leads to β-cell damage and promotes β-cells apoptosis, in types I and II of diabetes mellitus. Therefore, blocking of pro-inflammatory ...cytokines should be an effective way for the treatment of diabetes mellitus. When IL-1 occupies its receptor, various pro-inflammatory events are initiated including the synthesis and releases of chemokines and these chemokines attract neutrophils, macrophages, and lymphocytes that cause tissue inflammation. IL-1Ra is a naturally occurring cytokine and is the inhibitor of IL-1. When IL-1Ra binds to the IL-1 receptor, binding of IL-1 is blocked by IL-1Ra and pro-inflammatory signal from IL-1 receptor is stopped. There are mounting evidences to suggest that anti-inflammatory IL-1Ra reduces the inflammatory effects of IL-1 and preserves cell function in both types of diabetes. Therefore, IL-1Ra maybe a new therapeutic agent for diabetes mellitus types I and II. Mesenchymal stem cells (MSCs) are self-renewable multipotent stromal cells that have immunomodulatory capacity. Recently, well characterized subpopulations of MSCs which express IL-1Ra have been described. IL-1Ra expressed by these MSCs effectively binds to IL-1 receptor and protects tissues from inflammation-induced injuries. It has been previously shown that bone marrow-derived MSC therapy could be considered for the treatment of diabetes mellitus type 1 and complications of diabetes mellitus. This review presents understanding of potential use of IL-1Ra and MSCs as modulators of diabetogenesis.
Renewing interest in immune aspects of schizophrenia and new findings about the brain-fat axis encourage us to discuss the possible role of interleukin-6 (IL-6) in schizophrenia. Previously, it was ...suggested that a primary alteration of the innate immune system may be relevant in schizophrenia. Functional dichotomy of IL-6 suggests that this chemical messenger may be responsible for regulating the balance between pro- and anti-inflammatory responses, with tissue-specific properties at the periphery and in the central nervous system. Specific phase of this chronic and deteriorating disorder must be considered, which can involve IL-6 in acute or possible chronic inflammation and/or autoimmunity. We give an overview of IL-6 role in the onset and progression of this disorder, also considering cognitive impairment and metabolic changes in patients with schizophrenia. Data suggest that decreased serum level of IL-6 following antipsychotic therapy could be predisposing factor for the development of obesity and obesity-related metabolic disorders in schizophrenia. As we reviewed, the IL-6 plays significant role in disease genesis and progression, so the use of specific inhibitors may not only be beneficial for exacerbation and alleviation of positive symptoms, but may attenuate cognitive impairment in patients with schizophrenia.
We used concanavalin A (Con A)‐induced liver injury to study the role of galectin‐3 (Gal‐3) in the induction of inflammatory pathology and hepatocellular damage. We tested susceptibility to Con ...A–induced hepatitis in galectin‐3‐deficient (Gal‐3−/−) mice and analyzed the effects of pretreatment with a selective inhibitor of Gal‐3 (TD139) in wild‐type (WT) C57BL/6 mice, as evaluated by a liver enzyme test, quantitative histology, mononuclear cell (MNC) infiltration, cytokine production, intracellular staining of immune cells, and percentage of apoptotic MNCs in the liver. Gal‐3−/− mice were less sensitive to Con A–induced hepatitis and had a significantly lower number of activated lymphoid and dendritic cells (DCs) in the liver. The level of tumor necrosis factor alpha (TNFα), interferon gamma (IFNγ), and interleukin (IL)‐17 and ‐4 in the sera and the number of TNFα‐, IFNγ‐, and IL‐17‐ and ‐4‐producing cluster of differentiation (CD)4+ cells as well as IL‐12‐producing CD11c+ DCs were lower, whereas the number of IL‐10‐producing CD4+ T cells and F4/80+ macrophages were significantly higher in livers of Gal‐3−/− mice. Significantly higher percentages of late apoptotic Annexin V+ propidium‐idodide+ liver‐infiltrating MNCs and splenocytes were observed in Gal‐3−/− mice, compared to WT mice. Pretreatment of WT C57BL/6 mice with TD139 led to the attenuation of liver injury and milder infiltration of IFNγ‐ and IL‐17‐ and ‐4‐producing CD4+ T cells, as well as an increase in the total number of IL‐10‐producing CD4+ T cells and F4/80+ CD206+ alternatively activated macrophages and prevented the apoptosis of liver‐infiltrating MNCs. Conclusions: Gal‐3 plays an important proinflammatory role in Con A–induced hepatitis by promoting the activation of T lymphocytes and natural killer T cells, maturation of DCs, secretion of proinflammatory cytokines, down‐regulation of M2 macrophage polarization, and apoptosis of MNCs in the liver. (HEPATOLOGY 2012;55:1954–1964)
There is a plethora of evidence to suggest that Galectin-3 plays an important role in normal functions of mammalian cells, as well as in different pathogenic conditions. This review highlights recent ...data published by researchers, including our own team, on roles of Galectin-3 in the nervous system. Here, we discuss the roles of Galectin-3 in brain development, its roles in glial cells, as well as the interactions of glial cells with other neural and invading cells in pathological conditions. Galectin-3 plays an important role in the pathogenesis of neuroinflammatory and neurodegenerative disorders, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and Huntington's disease. On the other hand, there is also evidence of the protective role of Galectin-3 due to its anti-apoptotic effect in target cells. Interestingly, genetic deletion of Galectin-3 affects behavioral patterns in maturing and adult mice. The results reviewed in this paper and recent development of highly specific inhibitors suggests that Galectin-3 may be an important therapeutic target in pathological conditions including the disorders of the central nervous system.
PDF
