Vitamin D-deficiency induces eosinophil spontaneous activation.

Eosinophils (Eo) play a critical role in immunity and immune inflammation. The maintenance of Eo homeostasis is not fully understood yet. Vitamin D (VitD) is involved in the regulation of a large number of biochemical reactions. This study tests a hypothesis that VitD receptor (VDR) contributes to the homeostasis of Eos. In this study, EoL-1 cells (an Eo cell line) were cultured in the presence or absence of calcitriol. The Eo-mediators, including major basic protein (MBP), Eo peroxidase (EPX), Eo cationic protein (ECP) and Eo-derived neurotoxin (EDN), were assessed in the culture supernatant and in EoL-1 cells. We observed that, in a VitD deficient environment, EoL-1 cells produced high levels of the Eo-mediators, including MBP, EPX, ECP and EDN, which could be suppressed by the addition of calcitriol to the culture. EoL-1 cells expressed VitD receptor (VDR), which was up regulated by exposure to calcitriol. VDR formed complexes with the transcription factors of the Eo-mediators, which prevented the transcription factors to bind to the promoters of the Eo-mediators, and therefore prevented the Eo-mediated gene transcription. The Eo spontaneous activation was also found in the intestinal mucosa of VDR-deficient mice, in which the intestinal epithelial barrier dysfunction was observed. In conclusion, VDR contributes to the maintenance of the homeostasis of Eos by regulating the gene transcription of the Eo mediators. The VDR-deficiency is one of the causative factors inducing Eo spontaneous activation. This phenomenon may be taken into account in the management of the Eo-related diseases.

Inhibition of squamous cancer growth in a mouse model by Staphylococcal enterotoxin B-triggered Th9 cell expansion.

Currently, therapy for squamous cancer (SqC) is unsatisfactory. Staphylococcal enterotoxin B (SEB) has strong immune regulatory activity. This study tests the hypothesis that SEB enforces the effect of immunotherapy on SqC growth in a mouse model. C3H/HeN mice and the SqC cell line squamous cell carcinoma VII were used to create an SqC mouse model. Immune cell assessment was performed by flow cytometry. Real-time RT-PCR and western blotting were used to evaluate target molecule expression. An apoptosis assay was used to assess the suppressive effect of T helper-9 (Th9) cells on the SqC cells. The results showed that immunotherapy consisting of SEB plus SqC antigen significantly inhibited SqC growth in the mice. The frequency of Th9 cells was markedly increased in the SqC tissue and mouse spleens after treatment. SEB markedly increased the levels of signal transducer and activator of transcription 5 phosphorylation and the expression of histone deacetylase-1 (HDAC1) and PU.1 (the transcription factor of the interleukin 9 (IL-9) gene) in CD4+ T cells. Exposure to SqC-specific Th9 cells markedly induced SqC cell apoptosis both in vitro and in vivo. In conclusion, the administration of SEB induces Th9 cells in SqC-bearing mice, and theseTh9 cells inhibit SqC growth.

Micro RNA-19a interferes with IL-10 expression in peripheral dendritic cells of patients with nasal polyposis.

The pathogenesis of nasal polyp is to be further investigated. Micro RNA (miR) plays a role in the development of allergic inflammation. Interleukin (IL)-10-producing dendritic cells (DC) have immune tolerogenic properties. This study test a hypothesis that miR-17-92 cluster is associated with suppressing IL-10 in peripheral DC. In this study, peripheral blood samples were obtained from 26 patients with nasal polyp. The CD11c DCs were isolated from the blood samples and analyzed for the expression of IL-10. We observed that, as compared with healthy subjects, the IL-10 expression in peripheral DC was significantly lower in polyp patients. The levels of miR-19a, but not the rest 5 members of the miR-17-92 cluster, were markedly higher in DCs in polyp group. Exposure to recombinant IL-4 suppressed the IL-10 expression in DCs, which was abolished by blocking histone deacetylase-11 or knocking down the miR-19a gene in DCs. We conclude that miR-19a plays a critical role in the suppression of IL-10 in peripheral DCs, which may be a target in the immune therapy for nasal polyp.

Micro RNA-19a suppresses thrombospondin-1 in CD35+ B cells in the intestine of mice with food allergy.

Disruption of immune tolerance is associated in the pathogenesis of allergy. Thrombospondin-1 (TSP1) plays a role in the maintenance of immune tolerance, which is compromised in allergic disorders. Micro RNA (miR) is involved in the regulation of immune responses. This study tests a hypothesis that miR-17-92 cluster is involved in the regulation of TSP1 in the intestinal CD35+ B cells. In this study, a food allergy mouse model was developed. The intestinal B cells were isolated to be analyzed for the expression of a miR-17-92 cluster and TSP1. The role of miR-19a in the suppression of TSP1 in B cells was tested in a cell culture model. We observed that the levels of TSP1 were significantly decreased; the levels of miR-19a were significantly increased in intestinal CD35+ B cells of mice sensitized to ovalbumin (OVA) as compared with naïve controls. Exposure to interleukin (IL)-4 suppressed the expression of TSP1 in B cells, which was abolished by inhibition of miR-19a. miR-19a mediated the effects of IL-4 on repressing TSP1 expression in B cells. We conclude that IL-4 suppresses the expression of TSP1 in the intestinal CD35+ B cells via up regulating miR-19a. The miR-19a may be a target to regulate the immune tolerant status in the body.

Histone acetyltransferease p300 modulates TIM4 expression in dendritic cells.

TIM4 (T cell immunoglobulin mucin domain molecule-4) plays a critical role in the initiation of skewed T helper (Th) 2 polarization. The factors regulating TIM4 expression are unclear. This study tests a hypothesis that p300 and STAT6 (signal transducer and activator transcription-6) regulates TIM4 expression in dendritic cells (DC). In this study, a food allergy mouse model was developed with ovalbumin (a specific antigen) and cholera toxin (CT; an adjuvant). The chromatin immunoprecipitation assay was performed to evaluate the chromatin changes at TIM4 and STAT6 promoters. The TIM4 expression was evaluated by real time RT-PCR and Western blotting. The results showed that high levels of p300 and TIM4 were detected in the intestinal DCs of mice with intestinal allergy. p300 is involved in the CT-induced TIM4 expression in DCs. p300 interacts with the chromatin at the TIM4 promoter locus in DCs isolated from allergic mice. CT increases p300 expression to regulate STAT6 levels in DCs. STAT6 mediates the CT-induced TIM4 expression in DCs. In conclusion, p300 and STAT6 mediate the microbial product CT-induced TIM4 expression in DCs.

Induction of colitis in mice with food allergen-specific immune response.

The pathogenesis of intestinal chronic inflammation is unclear. Food allergy plays an important role in the induction of intestinal inflammation. This study aims to test a hypothesis that food allergy initiates colitis. In this study, BALB/c mice were sensitized to a common food allergen, ovalbumin (OVA) with cholera toxin (CT) as an adjuvant. The colon epithelial barrier function was assessed with Ussing chamber technique. Expression of T cell immunoglobulin mucin domain molecule-4 (TIM4) in dendritic cells was evaluated by flow cytometry, RT-PCR and Western blotting. The results showed that allergen-related colitis was induced in mice as shown by heavy infiltration of inflammatory cells in the colon mucosa, loss of body weight of mice, increases in myeloperoxidase, tumor necrosis factor-α, interleukin-4, OVA-specific IgE in the colon tissue. The colon epithelial barrier function was markedly compromised in colitis group mice, which was mimicked by exposure the colon mucosa to CT in Ussing chamber. High frequency of TIM4(+) dendritic cells was detected in the colon mucosa of colitis mice. Exposure of dendritic cells to CT markedly increased the expression of TIM4. We conclude that IBD-like inflammation can be induced in the mouse colon by the food allergen-related immune response.

Flagellin modulates IgE expression in B cells to initiate food allergy in mice.

The initiation mechanism of IgE expression has not been fully understood. Flagellin (FGN) is an important microbial factor in the regulation of immune responses in the intestine. This study tests a hypothesis that FGN plays a crucial role in the isotype switching of IgE in B cells and the initiation of food allergy. In this study, the expression of IgE in B cells was analyzed by real time RT-PCR, Western blotting and chromatin immunoprecipitation. A mouse model was developed to assess the role of Toll like receptor-5 in the development of IgE-mediated allergic reaction in the intestinal mucosa. The results showed that exposure to FGN suppressed the expression of Bcl6 in B cells via increasing the levels of histone deacetylase (HDAC) 7; the latter up regulated the levels of methylated H3K9 and H3K27, down regulated RNA polymerase II and STAT3 (signal transducer and activator of transcription 3) at the Bcl6 promoter locus. Exposure to FGN and IL-4 markedly increased the expression of IgE in B cells via activating p300, H3K4, Pol II and STAT6 at the IgE promoter locus. As compared with the sensitized wild mice, the sensitized TLR5-deficient mice showed no detectable OVA-specific IgE in the serum; mast cells in the intestinal mucosa were not activated, no apparent allergic symptoms were evoked after the specific antigen challenge. In conclusion, FGN facilitates the initiation of food allergy in mice by triggering IgE transcription in B cells in a Th2 polarization environment via activating HDAC7 and suppressing Bcl6 expression.

Specific immunotherapy ameliorates ulcerative colitis.

BACKGROUND: Hypersensitivity reaction to certain allergens plays a role in the pathogenesis of inflammatory bowel disease (IBD). This study aims to observe the effect of specific immunotherapy in a group of IBD patients. METHODS: Patients with both ulcerative colitis (UC) and food allergy were recruited into this study. Food allergy was diagnosed by skin prick test and serum specific IgE. The patients were treated with specific immunotherapy (SIT) and Clostridium butyricum (CB) capsules. RESULTS: After treating with SIT and CB, the clinical symptoms of UC were markedly suppressed as shown by reduced truncated Mayo scores and medication scores. The serum levels of specific IgE, interleukin (IL)-4 and tumor necrosis factor (TNF)-α were also suppressed. Treating with SIT alone or CB alone did not show appreciable improvement of the clinical symptoms of UC. CONCLUSIONS: UC with food allergy can be ameliorated by administration with SIT and butyrate-production probiotics.

Correlation analysis of gene polymorphisms and ß-lactam allergy.

A total of 64 patients with ß-lactam allergy and 30 control subjects were enrolled in a case-control study. This study is aimed to analyze the relationship between ß-lactam allergy and 10 single nucleotide polymorphisms (SNPs) in interleukin-10 (IL-10), IL-13, IL-4Rα, high-affinity immunoglobulin E-receptor ß chain (FcεRIß), interferon γ receptor 2 (IFNGR2), and CYP3A4, and within the Han Chinese population of Northwest China. Genotyping for the SNPs was conducted using the Sequenom MassARRAY(®) platform. SPSS 17.0 was employed to analyze the statistical data and SHEsis was used to perform the haplotype reconstruction and analyze linkage disequilibrium of SNPs of IL-10 and IL-13. The results showed that the genotype distribution of CYP3A4 rs2242480/CT differed significantly between case and control groups of males (P=0.022; odds ratio (OR)=0.167, 95% confidence interval (CI): 0.032-0.867). Further analysis showed that CCA, CCG, and TAA haplotypes of IL-10 had no significant correlation in patients with ß-lactam allergy. The correlation between CCT and CAC haplotypes of IL-13 and ß-lactam allergy needs to be further studied. The analysis did not reveal any differences in the distribution of others gene polymorphisms between cases and controls.

Role of interleukin-22 in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease thought to be mediated by the microbiota of the intestinal lumen and inappropriate immune responses. Aberrant immune responses can cause secretion of harmful cytokines that destroy the epithelium of the gastrointestinal tract, leading to further inflammation. Interleukin (IL)-22 is a member of the IL-10 family of cytokines that was recently discovered to be mainly produced by both adaptive and innate immune cells. Several cytokines and many of the transcriptional factors and T regulatory cells are known to regulate IL-22 expression through activation of signal transducer and activator of transcription 3 signaling cascades. This cytokine induces antimicrobial molecules and proliferative and antiapoptotic pathways, which help prevent tissue damage and aid in its repair. All of these processes play a beneficial role in IBD by enhancing intestinal barrier integrity and epithelial innate immunity. In this review, we discuss recent progress in the involvement of IL-22 in the pathogenesis of IBD, as well as its therapeutic potential.

Ebb-and-flow of macroautophagy and chaperone-mediated autophagy in Raji cells induced by starvation and arsenic trioxide.

Autophagy is crucial in the maintenance of homeostasis and regenerated energy of mammalian cells. Macroautophagy and chaperone-mediated autophagy(CMA) are the two best-identified pathways. Recent research has found that in normal cells, decline of macroautophagy is appropriately parallel with activation of CMA. However, whether it is also true in cancer cells has been poorly studied. Here we focused on cross-talk and conversion between macroautophagy and CMA in cultured Burkitt lymphoma Raji cells when facing serum deprivation and exposure to a toxic compound, arsenic trioxide. The results showed that both macroautophagy and CMA were activated sequentially instead of simultaneously in starvation-induced Raji cells, and macroautophagy was quickly activated and peaked during the first hours of nutrition deprivation, and then gradually decreased to near baseline. With nutrient deprivation persisted, CMA progressively increased along with the decline of macroautophagy. On the other hand, in arsenic trioxide-treated Raji cells, macroautophagy activity was also significantly increased, but CMA activity was not rapidly enhanced until macroautophagy was inhibited by 3-methyladenine, an inhibitor. Together, we conclude that cancer cells exhibit differential responses to diverse stressor-induced damage by autophagy. The sequential switch of the first-aider macroautophagy to the homeostasis-stabilizer CMA, whether active or passive, might be conducive to the adaption of cancer cells to miscellaneous intracellular or extracellular stressors. These findings must be helpful to understand the characteristics, compensatory mechanisms and answer modes of different autophagic pathways in cancer cells, which might be very important and promising to the development of potential targeting interventions for cancer therapies via regulation of autophagic pathways.

Arsenic trioxide induces autophagy and antitumor effects in Burkitt's lymphoma Raji cells.

Although it is generally acknowledged that auto-phagy plays an important role in tumorigenesis and therapy, studies of autophagy in different cell types and under different conditions have led to conflicting theories regarding the influence of autophagy on cell death. In the present study, we explored the role of autophagy and its underlying mechanism in the inhibitory effects of arsenic trioxide (As2O3) on Burkitt's lymphoma Raji cells. The results showed that As2O3 significantly inhibited the proliferation of Raji cells in a dose- and time-dependent manner, induced G2/M phase cell cycle arrest and apoptosis. Moreover, As2O3 also promoted the formation of autophagic vacuoles, as well as increased the degradation of autophagy substrate P62 protein, which was accompanied by an upregulation of Beclin-1 gene and a downregulation of Bcl-2 gene expression. 3-Methyladenine, an autophagy inhibitor, not only increased cell viability through inhibiting autophagic cell death and apoptosis, but also reversed the upregulation of Beclin-1 gene and the downregulation of Bcl-2 gene in the Raji cells induced by As2O3. These results may lead to a better understanding of the action of As2O3 and may provide evidence that autophagy plays an important role in the regulation of cell death. Therefore, regulation of autophagic activity may be a promising therapy for patients with Burkitt's lymphoma.

Insulin resistance reduces sensitivity to Cis-platinum and promotes adhesion, migration and invasion in HepG2 cells.

The liver is normally the major site of glucose metabolism in intact organisms and the most important target organ for the action of insulin. It has been widely accepted that insulin resistance (IR) is closely associated with postoperative recurrence of hepatocellular carcinoma (HCC). However, the relationship between IR and drug resistance in liver cancer cells is unclear. In the present study, IR was induced in HepG2 cells via incubation with a high concentration of insulin. Once the insulin-resistant cell line was established, the instability of HepG2/ IR cells was further tested via incubation in insulin-free medium for another 72h. Afterwards, the biological effects of insulin resistance on adhesion, migration, invasion and sensitivity to cis-platinum (DDP) of cells were determined. The results indicated that glucose consumption was reduced in insulin-resistant cells. In addition, the expression of the insulin receptor and glucose transportor-2 was downregulated. Furthermore, HepG2/IR cells displayed markedly enhanced adhesion, migration, and invasion. Most importantly, these cells exhibited a lower sensitivity to DDP. By contrast, HepG2/IR cells exhibited decreased adhesion and invasion after treatment with the insulin sensitizer pioglitazone hydrochloride. The results suggest that IR is closely related to drug resistance as well as adhesion, migration, and invasion in HepG2 cells. These findings may help explain the clinical observation of limited efficacy for chemotherapy on a background of IR, which promotes the invasion and migration of cancer cells.

Ghrelin antagonizes MPTP-induced neurotoxicity to the dopaminergic neurons in mouse substantia nigra.

Ghrelin, a stomach-derived hormone which induces growth hormone release and promotes positive energy balance, has been reported to inhibit cell apoptosis in endotheliocytes, osteoblasts and cardiocytes. Recent evidence has shown that ghrelin can also inhibit neuronal apoptosis of the hypothalamus and the hippocampus. However, little is known about the effects of ghrelin on the substantia nigra pars compacta (SNpc) neurons in which ghrelin's receptor, growth hormone secretagogue receptor (GHSR)-1a, is highly expressed. In the present study, we investigated whether ghrelin could protect nigral dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in mice. We observed that ghrelin, acting through GHS-R 1a, inhibited MPTP-induced dopaminergic neuronal loss in the SNpc as well as dopamine depletion in the striatum. Ghrelin could also reverse the down-regulated the expression of Bcl-2, up-regulated the expression of Bax, and caspase-3 activation caused by MPTP. This study demonstrated that ghrelin might be a potential protector of dopaminergic neurons in a therapeutic strategy for Parkinson's disease.