Induction of anti-inflammatory responses by dietary Momordica charantia L. (bitter gourd)

We assessed the immunomodulatory activity of Momordica charantia L. (bitter gourd), a vegetable that has been reported to possess various bioactivities. We examined the effect of bitter gourd on intestinal immunity by monitoring the TGF-beta and IL-7 secretion from Caco-2 cells and the IL-10 and IL-12 secretion from THP-1 cells that are used as in vitro models of the intestinal epithelium and monocyte/macrophages, respectively. We also determined the in vivo immunological responses of rats fed on bitter gourd for 3 weeks. We found that bitter gourd induced a decrease in the intestinal secretion of IL-7 and an increase in the secretions of TGF-beta and IL-10, these effects reflecting the bitter gourd-induced changes in systemic immunity, i.e., a decrease in the number of lymphocytes, increases in the populations of Th cells and NK cells, and increase in the Ig production of lymphocytes. Dietary bitter gourd may therefore induce both intestinal and also systemic anti-inflammatory responses.     

Th17 responses in Echinostoma caproni infections in hosts of high and low compatibility

In order to investigate the factors determining the expulsion of intestinal helminths, we have analyzed the in vivo expression of IL-17, TGF-β and IL-23 in several tissues of two host species displaying different compatibility with Echinostoma caproni (Trematoda). We did not observe upregulation of these cytokines in any of the tissues of the high compatible host (mice). In contrast, the responses in the host of low compatibility (rats) with the parasite were markedly different. Significant increases in the expression of IL-17 and TGF-β were observed in the Peyer’s patches and the intestine from the 2 to 8 weeks post-infection. The expression of IL-23 was upregulated from 2 to 4 weeks post-infection in the spleen, Peyer’s patches and the intestine. Considering together our results with those published previously the development of chronic infections appears to be related with the development of local Th1 responses, whereas the early rejection of the worms is mediated by the development a biased Th17/Th2 phenotype. The Th17 response generated in rats may facilitate the worm expulsion via the suppression of the inflammatory Th1 responses and the increase in intestinal contractility.     

B cell infiltration is associated with the increased IL-17 and IL-22 expression in the lungs of patients with tuberculosis

Although it has been recognized that ectopic follicle-like B cell aggregate formation is common in the lungs of patients with tuberculosis, the role of infiltrated B cells in human tuberculosis remains to be elucidated. In the present study, we showed that ectopic B cell aggregate formation was associated with containment of Mycobacterium tuberculosis. The area ratio of ectopic B cell aggregates was correlated with localized IL-17 mRNA expression and peripheral TGF-β and IL-6 mRNA expression. Depletion of B cells from pleural fluid mononuclear cells resulted in significantly diminished M. tuberculosis antigen-specific IL-17 and IL-22 production, but not in IFN-γ secretion. Therefore, ectopic lung B cell formation is important for containment of M. tuberculosis, and up-regulation of IL-17 and IL-22 responses may be an important mechanism underlying the protective role B cells in human tuberculosis.     

The effects of oxygen–ozone therapy on regulatory T-cell responses in multiple sclerosis patients

Multiple sclerosis (MS) is a common degenerative disorder of the central nervous system. The decreased frequency and dysfunction of Treg cells cause inflammation and disease progression. Ozone autohemotherapy can be used as a potential therapeutic approach to regulate the immune system responses and inflammation in MS. For this purpose, 20 relapsing-remitting multiple sclerosis patients were under treatment with ozone twice weekly for 6 months. The frequency of Treg cell, the expression levels of the Treg cell-related factors (FoxP3, IL-10, TGF-β, miR-17, miR-27, and miR-146A), and the secretion levels of IL-10 and TGF-β were assessed. We found a significant increase in the number of Treg cells, expression levels of FoxP3, miRNAs (miR-17 and miR-27), IL-10, and TGF-β factors in patients after oxygen–ozone (O₂-O₃) therapy compared to before treatment. In contrast, oxygen–ozone therapy notably decreased the expression level of miR-146a in treated patients. Interestingly, the secretion levels of both IL-10 and TGF-β cytokines were considerably increased in both serum and supernatant of cultured peripheral blood mononuclear cells in posttreatment condition compared to pretreatment condition. According to results, oxygen–ozone therapy raised the frequency of Treg cell and its relevant factors in treated MS patients. Oxygen–ozone therapy would contribute to improving the MS patients by elevating the Treg cell responses.     

Role of TGF-β and IL-6 in dendritic cells,Treg and Th17 mediated immune response during experimental cerebral malaria

The role of cytokines in Plasmodium infection have been extensively investigated, but pro and anti inflammatory cytokines mediated imbalance during malaria immune-pathogenesis is still unrevealed. Malaria is associated with the circulating levels of Interleukin-6 (IL-6) and transforming growth factor β (TGF-β), but association between these two cytokines in immune response remains largely obscured. Using mouse model, we proposed that IL-6 and TGF-β are involved in immune regulation of dendritic cells (DC), regulatory T cells (Treg), T-helper cells (Th17) during P. berghei ANKA (PbA) infection. Association between the cytokines and the severity of malaria was established with anti-TGF-β treatment resulting in increased parasitemia and increased immunopathology, whereas; anti-IL-6 treatment delays immunopathology during PbA infection. Further, splenocytes revealed differential alteration of myeloid DC (mDC), plasmocytoid DC (pDC), Treg, Th17 cells following TGF-β and IL-6 neutralization. Interestingly anti-TGF-β reduces CD11c⁺CD8⁺ DC expression, whereas anti-IL-6 administration causes a profound increase during PbA infection in Swiss mice. We observed down regulation of TGF-β, IL-10, NFAT, Foxp3, STAT-5 SMAD-3 and upregulation of IL-6, IL-23, IL-17 and STAT-3 in splenocytes during PbA infection. The STAT activity probably plays differential role in induction of Th17 and Treg cells. Interestingly we found increase in STAT-3 and decrease in STAT-5 expression during PbA infection. This pattern of STAT indicates that possibly TGF-β and IL-6 play a crucial role in differentiation of DCs subsets and Treg/Th17 imbalance during experimental cerebral malaria (ECM).     

IL-11 expression in retinal and corneal cells is regulated by interferon-γ

Interleukin-11 (IL-11) is an anti-apoptotic, anti-inflammatory cytokine with hematopoietic potential. The expression and protective actions of IL-11 have not been explored in the eye. The expression of IL-11 in primary cultures of human retinal pigment epithelial (HRPE) and human corneal fibroblast (HCRF) cells were evaluated in these studies. Constitutive secretion of IL-11 was not observed in either HRPE or HCRF. TNF-α + IL-1 induced IL-11 secretion and this production was inhibited by NFκB pathway inhibitors. IFN-γ significantly inhibited TNF-α and IL-1 induced IL-11 secretion and inhibitors of JAK-STAT pathway reversed this inhibition. TGF-β induced IL-11 secretion that was blocked by TGF-β receptor 1 inhibitor but not by IFN-γ. RT-PCR analysis confirmed the effects of IL-1, TNF-α, IFN-γ and TGF-β on IL-11 secretion at mRNA levels. Our results demonstrate that IL-11 is dramatically up regulated in retina and cornea cells and that IFN-γ is a physiological inhibitor of IL-11 expression.     

Role of pulmonary epithelial arginase-II in activation of fibroblasts and lung inflammaging

Elevated arginases including type-I (Arg-I) and type-II isoenzyme (Arg-II) are reported to play a role in aging, age-associated organ inflammaging, and fibrosis. A role of arginase in pulmonary aging and underlying mechanisms are not explored. Our present study shows increased Arg-II levels in aging lung of female mice, which is detected in bronchial ciliated epithelium, club cells, alveolar type 2 (AT2) pneumocytes, and fibroblasts (but not vascular endothelial and smooth muscle cells). Similar cellular localization of Arg-II is also observed in human lung biopsies. The age-associated increase in lung fibrosis and inflammatory cytokines, including IL-1β and TGF-β1 that are highly expressed in bronchial epithelium, AT2 cells, and fibroblasts, are ameliorated in arg-ii deficient (arg-ii^−/−) mice. The effects of arg-ii^−/− on lung inflammaging are weaker in male as compared to female animals. Conditioned medium (CM) from human Arg-II-positive bronchial and alveolar epithelial cells, but not that from arg-ii^−/− cells, activates fibroblasts to produce various cytokines including TGF-β1 and collagen, which is abolished by IL-1β receptor antagonist or TGF-β type I receptor blocker. Conversely, TGF-β1 or IL-1β also increases Arg-II expression. In the mouse models, we confirmed the age-associated increase in IL-1β and TGF-β1 in epithelial cells and activation of fibroblasts, which is inhibited in arg-ii^−/− mice. Taken together, our study demonstrates a critical role of epithelial Arg-II in activation of pulmonary fibroblasts via paracrine release of IL-1β and TGF-β1, contributing to pulmonary inflammaging and fibrosis. The results provide a novel mechanistic insight in the role of Arg-II in pulmonary aging.     

TGF-β is necessary for induction of IL-23R and Th17 differentiation by IL-6 and IL-23

TGF-β and IL-6 induce Th17 differentiation, and IL-23 is required for expansion and maintenance of Th17 cells. Recently, it was shown that IL-6 up-regulates IL-23R mRNA in naive CD4⁺ T cells and therefore IL-6 and IL-23 synergistically promote Th17 differentiation. However, the molecular mechanism whereby IL-6 and IL-23 induce Th17 differentiation and the relevance to TGF-β remain unknown. Here, we found that IL-6 up-regulated IL-23R mRNA expression, and IL-6 and IL-23 synergistically augmented its protein expression. The combination induced Th17 differentiation, and TGF-β1 further enhanced it. IL-6 augmented endogenous TGF-β1 mRNA expression, whereas the amount of TGF-β produced was not enough to induce Th17 differentiation by IL-6 alone. However, unexpectedly, the up-regulation of IL-23R and induction of Th17 differentiation by IL-6 and IL-23 were almost completely inhibited by anti-TGF-β. These results suggest that the induction of IL-23R and Th17 differentiation by IL-6 and IL-23 is mediated through endogenously produced TGF-β.     

Transforming growth factor-β and Th17 responses in resistance to primary murine schistosomiasis mansoni

Discovery of the T-helper (Th) 17 cell lineage and functions in immune responses of mouse and man prompted us to investigate the role of transforming growth factor-beta (TGF-β) and interleukin (IL)-17 in innate resistance to murine schistosomiasis mansoni. Schistosoma mansoni-infected BALB/c and C57BL/6 mice were administered with recombinant TGF-β or mouse monoclonal antibody to TGF-β to evaluate the impact of this cytokine on host immune responses against lung-stage schistosomula, and subsequent effects on adult worm parameters. Developing schistosomula elicited increase in peripheral blood mononuclear cells (PBMC) mRNA expression and/or plasma levels of IL-4, IL-17, and interferon-gamma (IFN-γ), cytokines known to antagonize each other, resulting in impaired Th1/Th2, and Th17 immune responses and parasite evasion. Mice treated with TGF-β showed elevated PBMC mRNA expression of IL-6, IL-17, TGF-β, and TNF-α mRNA and increased IL-23 and IL-17 or TGF-β plasma levels, associated with significantly (P < 0.02–<0.0001) lower S. mansoni adult worm burden compared to controls in both mouse strains, thus suggesting that TGF-β led to heightened Th17 responses that mediated resistance to the infection. Mice treated with antibody to TGF-β showed increase in PBMC mRNA expression and plasma levels of IL-4, IL-12p70, and IFN-γ, and significantly (P < 0.02 and <0.0001) reduced worm burden and liver worm egg counts than untreated mice, indicating that Th1/Th2 immune responses were potentiated, resulting in significant innate resistance to schistosomiasis. The implications of these observations for schistosome immune evasion and vaccination were discussed.     

Inflammasome components caspase-1 and adaptor protein apoptosis-associated speck-like proteins are important in resistance to Cryptosporidium parvum

Cryptosporidium spp. are opportunistic protozoan parasites that infect epithelial cells in the intestinal tract and cause a flu-like diarrheal illness. Innate immunity is key to limiting the expansion of parasitic stages early in infection. One mechanism in which it does this is through the generation of early cytokines, such as IL-18. The processing and secretion of mature IL-18 (and IL-1β) is mediated by caspase-1 which is activated within an inflammasome following the engagement of inflammasome-initiating sensors. We examined how the absence of caspase-1 and caspase-11, the adapter protein Asc, and other inflammasome components affects susceptibility to cryptosporidial infection by these and other key cytokines in the gut. We found that Casp-11^?/?Casp-1^?/? knockout mice have increased susceptibility to Cryptosporidium parvum infection as demonstrated by the 35-fold higher oocyst production (at peak infection) compared to wild-type mice. Susceptibility correlated with a lack of IL-18 in caspase-1 and caspase1/11 knockout mice, whereas IL-18 is significantly elevated in wildtype mice. IL-1β was not generated in any significant amount following infection nor was any increased susceptibility observed in IL-1β knockout mice. We also show that the adapter protein Asc is important to susceptibility, and that the caspase-1 canonical inflammasome signaling pathway is the dominant pathway in C. parvum resistance.     

Ozone therapy restores immune dysfunction in refractory idiopathic granulomatous mastitis as a novel potential therapeutic approach

Immunological dysfunction has been suggested to play a major role in the pathogenesis of idiopathic granulomatous mastitis (IGM). We recently showed that ozone therapy was effective in patients with steroid-resistant IGM. This study assessed alterations in intracellular cytokine expression patterns in different T-lymphocyte subsets after ozone therapy in refractory IGM. Peripheral blood T lymphocyte subsets (CD8⁺, CD4⁺, CD4⁺CD25⁺CD127⁻) were analyzed via flow-cytometry for intracellular cytokine expressions IFN-γ, TNF-α, IL-10, and TGF-β before and after completion of 4-month systemic ozone therapy. Ozone therapy significantly increased the CD4⁺IFN-γ⁺ (p = 0.032), CD4⁺TNF-α⁺ (p = 0.028), and the CD8⁺TNF-α⁺ (p = 0.012) T cells. In contrast, significant decreases in CD4⁺ IL-10⁺ (p = 0.047) and CD8⁺IL-10⁺ T cells (p = 0.022) and CD4⁺CD25⁺CD127^−//low Treg cells secreting TGF-β (p = 0.005) were found after ozone therapy. When patients were analyzed according to the response to ozone therapy, patients with a complete remission were more likely to have increased CD3⁻CD16⁺CD56⁺ natural killer cells (p = 0.0027) and decreased CD19⁺ B lymphocytes (p = 0.046) following ozone therapy. Our results suggest that ozone therapy stimulated a T-helper-1 response associated with IFN-γ production and downregulation of TGF-β expression in CD4⁺CD25⁺CD127⁻ Treg cells. These alterations in the immune system following ozone therapy can improve wound healing and restore immune dysfunction in patients with refractory IGM.     

Intestinal immunostimulatory activity of neutral polysaccharide isolated from traditionally fermented Korean brown rice vinegar

In this study, diverse intestinal immunostimulatory activities were demonstrated for polysaccharides (KBV-CP) isolated from Korean brown rice vinegar. Monosaccharide composition analysis indicated that KBV-CP was composed mainly of neutral sugar units, primarily glucose and mannose. In vitro, KBV-CP significantly augmented the productions of immunoglobulin A (IgA) and IgA-related cytokines such as interleukin-6 (IL-6) and transforming growth factor-β (TGF-β) in a dose-dependent manner. Furthermore, results of an in vitro co-culture system of intestinal Caco-2 cells and RAW 264.7 macrophage cells suggested that KBV-CP is not only cytotoxic to Caco-2 cells but also capable of being transported across the small intestinal barrier. Oral administration of KBV-CP every other day for 20 days induced the IgA production by Peyer’s patch cells as well as in intestinal fluid and fecal extract. In addition, the production of IgA-related cytokines such as TGF-β and IL-6, and granulocyte macrophage colony-stimulating factor was triggered.     

Growth factor TGF-β induces intestinal epithelial cell (IEC-6) differentiation: miR-146b as a regulatory component in the negative feedback loop

TGF-β is a potent pleiotropic factor that promotes small intestinal cell differentiation. The role of microRNAs in the TGF-β induction of intestinal epithelial phenotype is largely unknown. We hypothesized that microRNAs are functionally involved in TGF-β-induced intestinal cell growth. In this study, TGF-β caused a morphological change of IEC-6 cells and stimulated expression of the epithelial cell markers alkaline phosphatase, villin, and aminopeptidase N. By global microRNA profiling during TGF-β-induced intestinal crypt cell (IEC-6) differentiation, we identified 19 differentially expressed microRNAs. We showed by real-time Q-PCR that miR-146b expression increased rapidly after TGF-β treatment; sequence analysis and in vitro assays revealed that miR-146b targets SIAH2, an E3 ubiquitin ligase, with decreased protein expression upon IEC-6 cell differentiation. Transfection of miR-146b inhibitor before TGF-β treatment blocked the down-regulation of SIAH2 in response to TGF-β. Moreover, SIAH2 over-expression during TGF-β treatment caused a significant decrease in Smad7 protein expression in IEC-6 cells. Furthermore, activation of the ERK1/2 pathway is active in the up-regulation of miR-146b by TGF-β. These findings suggest a novel mechanism whereby TGF-β signaling during IEC-6 cell differentiation may be modulated in part by microRNAs, and we propose a key role for miR-146b in the homeostasis of growth factor TGF-β signaling through a negative feedback regulation involving down-regulation of SIAH2 repressed Smad7 activities.     

IL-17F deficiency inhibits small intestinal tumorigenesis in Apc mice

IL-17 plays an important role in gut homeostasis. However, the role of IL-17F in intestinal tumorigenesis has not been addressed. Here we demonstrate that ablation of IL-17F significantly inhibits spontaneous intestinal tumorigenesis in the small intestine of Apc^Min/+ mice. IL-17F ablation decreased IL-1β and Cox-2 expression as well as IL-17 receptor C (IL-17RC) expression, which were increased in tumors from Apc^Min/+ mice. Lack of IL-17F did not reverse the splenomegaly but partially restored thymic atrophy, suggesting a local effect of IL-17F in the intestine. IL-17F deficient Apc^Min/+ mice showed a significant decrease in immune cell infiltration in the lamina propria. Interestingly, the expression of IL-17A from CD4 T cells in the lamina propria remains unchanged in the absence of IL-17F. Collectively, our results suggest the proinflammatory and essential role of IL-17F to develop spontaneous intestinal tumorigenesis in Apc^Min/+ mice in the presence of IL-17A.     

IL-10 producing CD8+ T cells in human infection with Leishmania guyanensis

Cytokines are increasingly recognized as important components of the cellular immune responses to intracellular pathogens. In this study, we analyzed the production of TGF-β, IL-10 and IFN-γ by PBMC of unexposed naïve subjects and LCL patients after stimulation with live Leishmania guyanensis (L.g.). We demonstrated that IFN-γ is produced in controls and LCL patients, IL-10 only in LCL patients and TGF-β only in naïve subjects. Furthermore, in naive subjects, neutralization of TGF-β induced IL-10 production. IL-10 produced in naïve subjects when TGF-β is neutralized or in LCL patients did not modify the IFN-γ production but inhibit reactive nitrogen species production. Analysis of the phenotype of IL-10 producing cells in naive subjects when TGF-β is neutralized clearly showed that they are memory CD45RA⁻ CD8⁺ T cells. In LCL patients, IL-10 producing cells are both CD45RA⁻ CD4 and CD8⁺ T cells. The role of these IL-10 producing CD8⁺ T cells in the development of the diseases should be carefully evaluated.