Ming-Ling Kuo

Decreased Interleukin-10 Secretion by Peripheral Blood Mononuclear Cells in Children With Irritable Bowel Syndrome

Background and Aims: The aim of the present study was to evaluate proinflammatory and anti-inflammatory cytokine levels in children with irritable bowel syndrome (IBS). Patients and Methods: Thirty-five children with IBS (17 diarrhea-predominant, 7 constipation-predominant, and 11 mixed type) and 25 healthy children as healthy controls (HCs) were enrolled. All of the participants completed a questionnaire recording the duration, severity, and associated academic and social influences. Peripheral blood mononuclear cells were isolated and cultured for 24 hours with and without 1 or 5 ng/mL Escherichia coli lipopolysaccharide (LPS). Cytokine production including tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-10 was measured using enzyme-linked immunosorbent assays. Results: Children with IBS revealed lower baseline and significantly lower IL-10 levels after LPS stimulation compared with HCs (P = 0.001). Although not to a significant level, TNF-α and IL-6 levels were higher in children with IBS compared with HCs. The IL-10 levels in patients with IBS with strong pain intensity were lower both in baseline and under 1 ng/mL LPS stimulation. The levels became significantly lower under 5 ng/mL LPS stimulation compared with those experiencing mild and moderate pain intensity (P = 0.025). Conclusions: Our study suggests that children with IBS tend to produce lower amounts of the anti-inflammatory cytokine IL-10 at baseline and after LPS stimulation, implying that defects in immune modulation may contribute to IBS in children.

Matrine attenuates allergic airway inflammation and eosinophil infiltration by suppressing eotaxin and Th2 cytokine production in asthmatic mice

ETHNOPHARMACOLOGICAL RELEVANCE Matrine has been isolated from Sophora flavescens, and found to show anti-inflammatory effects in macrophages and anti-cachectic effects in hepatomas. The present study investigated whether matrine suppressed eosinophil infiltration and airway hyperresponsiveness (AHR) in mice, and decreased the inflammatory response of tracheal epithelial cells. MATERIALS AND METHODS BALB/c mice were sensitized and challenged with ovalbumin to induce allergic asthma in mice. These asthmatic mice were given various doses of matrine by intraperitoneal injection. Additionally, activated human tracheal epithelial cells (BEAS-2B cells) were treated with matrine, and evaluated for levels of proinflammatory cytokines and chemokines. RESULTS We found that matrine significantly decreased AHR, and suppressed goblet cell hyperplasia, eosinophil infiltration, and inflammatory response in the lung tissue of asthmatic mice. Matrine also reduced the levels of Th2 cytokines and chemokines in bronchoalveolar lavage fluid, and suppressed OVA-IgE production in serum. Furthermore, matrine treatment of activated BEAS-2B cells decreased production of proinflammatory cytokines and eotaxins, as well as suppressed ICAM-1 expression and thus adhesion of eosinophils to inflammatory BEAS-2B cells in vitro. CONCLUSIONS Our findings suggest that matrine can improve allergic asthma in mice, and therefore has potential therapeutic potential in humans.

The DNA Methylation Inhibitor 5-Azacytidine Increases Regulatory T Cells and Alleviates Airway Inflammation in Ovalbumin-Sensitized Mice

Background: Asthma is characterized as a chronic inflammatory disorder of the airways associated with an enhanced TH2 response to inhaled allergens. CD4+ T regulatory (Treg) cells are controlled by the master transcription factor FoxP3 and strictly maintain peripheral immunotolerance. Epigenetic regulation of FoxP3 by DNA methyltransferase inhibitors, such as 5-azacytidine (Aza), can generate a steady supply of functional Treg cells. Therefore, we propose that Aza can augment Treg cells in vivo to prevent the pathogenesis of asthma. Methods: BALB/c mice were sensitized with chicken ovalbumin (OVA) and treated with different doses of Aza. Airway hyperresponsiveness to methacholine, eosinophilia in bronchoalveolar lavage fluid, circulating titers of OVA-specific IgG1 and IgE, and stimulating levels of TH2 cytokines from splenocytes were then determined. Cellular populations were examined by flow cytometry. PC61 antibody, which depletes CD25+ cells, was used to verify the role of CD25+ cells in Aza-induced tolerance. Results: Administration of Aza to OVA-sensitized mice diminished airway hyperreactivity, pulmonary eosinophilia, levels of OVA-specific IgG1 and IgE in serum, and secretion of TH2 cytokines from OVA-stimulated splenocytes in a dose-dependent manner. Percentages of CD25+ and FoxP3+ cells in the CD4+ cell population were notably increased in Aza-treated mice compared to sensitized control mice. Furthermore, the major symptoms of asthma were exacerbated by depleting CD25+ cells in Aza-treated mice. Conclusions: Aza may have applications as a novel clinical strategy to increase the production of Treg cells in order to modulate the airway inflammation associated with asthma.

The regulatory function of umbilical cord blood CD4(+) CD25(+) T cells stimulated with anti-CD3/anti-CD28 and exogenous interleukin (IL)-2 or IL-15.

The abundance of CD4+ CD25+ regulatory T cells in umbilical cord blood (UCB) might contribute to the decreased severity of graft‐vs.‐host disease (GVHD) for UCB transplantation. This study aims to characterize the phenotypes and suppressive function of UCB CD4+ CD25+ T cells under the influence of anti‐CD3/anti‐CD28 (CD3/CD28) and exogenous interleukin (IL)‐2 or IL‐15. Higher percentages of CD4+ CD25high and FoxP3+ cells were detected in UCB compared to their adult counterparts. IL‐15 was as effective as IL‐2 in enhancing the proliferation of CD3/CD28 stimulated UCB CD4+ CD25+ T cells. Phenotypically, IL‐2/IL‐15‐stimulated UCB CD4+ CD25+ T cells expressed higher level of CTLA‐4, GITR, membrane bound transforming growth factor‐β (mTGF‐β), and especially Foxp‐3 than controls. IL‐2/IL‐15‐stimulated UCB CD4+ CD25+ T cells also produced much higher IL‐10 and TGF‐β than controls; while IL‐2/IL‐15‐stimulated UCB CD4+ CD25− T cells showed increased TGF‐β, but not IL‐10 production. IL‐2/IL‐15‐cultured UCB CD4+ CD25+ T cells showed comparable suppressor activity on allogeneic adult CD4+ T‐cell proliferation compared to controls, partly through a contact‐dependent fashion. Taken together, IL‐2/IL‐15‐stimulated UCB CD4+ CD25+ T cells show distinct regulatory T‐cell phenotypic and functional features, and may be applied for the alleviation of GVHD severity following UCB transplantation.

Attenuated Salmonella typhimurium reduces ovalbumin-induced airway inflammation and T-helper type 2 responses in mice.

Cytokines produced by Th2 cells are responsible for the pathogenesis of asthma. Th1‐biased immune responses caused by attenuated salmonella have the potential to relieve asthmatic symptoms. We evaluated whether oral administration of attenuated salmonella could modulate allergic responses in a chicken ovalbumin (OVA)‐induced asthmatic murine model. Mice were fed with attenuated salmonella SL7207 one dose before and three doses during the induction of an allergic response. Lung histology, percentages of eosinophil in bronchoalveolar lavage fluid, serum levels of OVA‐specific antibodies and cytokine production by OVA‐activated splenocytes were evaluated in mice with or without the administration of SL7207. A significant reduction in pulmonary eosinophilic infiltration was observed in mice receiving attenuated salmonella. Lower levels of OVA‐specific IgG1 but higher titres of OVA‐IgG2a in serum were also detected in this group. Splenocytes from salmonella‐fed mice produced lower levels of Th2 cytokines upon OVA stimulation. The administration of attenuated salmonella significantly suppressed immunopathological symptoms in OVA‐sensitized mice. Inhibition of Th2 responses might explain the potential mechanisms. This study provides some evidence for the feasibility of attenuated salmonella as an effective vaccine for allergic diseases.

Oral lovastatin attenuates airway inflammation and mucus secretion in ovalbumin-induced murine model of asthma.

Purpose Lovastatin is an effective inhibitor of cholesterol synthesis. A previous study demonstrated that lovastatin can also suppress airway hyperresponsiveness (AHR) in murine model of asthma. We aimed to investigate the effect of lovastatin on mucus secretion and inflammation-associated gene expression in the lungs of murine model of asthma. Methods Female BALB/c mice were sensitized and challenged with ovalbumin (OVA) by intraperitoneal injection, and orally administered lovastatin from days 14 to 27 post-injection. Gene expression in lung tissues was analyzed using real-time polymerase chain reaction. AHR and goblet cell hyperplasia were also examined. BEAS-2B human bronchial epithelial cells were used to evaluate the effect of lovastatin on the expression of cell adhesion molecules, chemokines, and proinflammatory cytokines in vitro. Results We showed that lovastatin inhibits the expression of Th2-associated genes, including eotaxins and adhesion molecules, in the lungs of murine model of asthma. Mucin 5AC expression, eosinophil infiltration and goblet cell hyperplasia were significantly decreased in the lung tissue of murine model of asthma treated with lovastatin. Furthermore, lovastatin inhibited AHR and expression of Th2-associated cytokines in bronchoalveolar lavage fluid. However, a high dose (40 mg/kg) of lovastatin was required to decrease specific IgE to OVA levels in serum, and suppress the expression of Th2-associated cytokines in splenocytes. Activated BEAS-2B cells treated with lovastatin exhibited reduced IL-6, eotaxins (CCL11 and CCL24), and intercellular adhesion molecule-1 protein expression. Consistent with this, lovastatin also suppressed the ability of HL-60 cells to adhere to inflammatory BEAS-2B cells. Conclusions These data suggest that lovastatin suppresses mucus secretion and airway inflammation by inhibiting the production of eotaxins and Th2 cytokines in murine model of asthma.

Azithromycin Inhibits IL-5 Production of T Helper Type 2 Cells from Asthmatic Children

Background: Childhood asthma is a type 2 helper T (Th2) cell-driven inflammatory airway disease characterized by recurrent episodes of airway obstruction. Azithromycin (AZM), a macrolide antibiotic exhibiting anti-inflammatory activity aside from its antibacterial effect, may prove beneficial for asthmatic children. This study aimed to determine the effect of AZM on Th2 cells from atopic asthmatic children and non-atopic controls. Methods: CD4+ cells were isolated from peripheral blood mononuclear cells of 9 patients with asthma and 9 non-atopic individuals. Cells were activated as Th0 and differentiated into Th2 cells. The effect of AZM on activated CD4+ cells was evaluated with respective cell proliferation and cytokine production. Results: Th0 and Th2 CD4+ T cells from atopic asthmatic children produced greater interleukin (IL)-5 (Th2 cytokine) but lower interferon (IFN)-γ (Th1 cytokine) compared to the non-atopic controls, respectively. AZM inhibited IL-5 production of Th0 and Th2 cells from atopic asthmatics in a dose-dependent fashion, without significantly affecting their IL-13 and IFN-γ production. A similar effect was observed in non-atopic controls except that AZM did inhibit IFN-γ production of their Th0 cells. AZM at a higher dose decreased cell viability by inhibiting CD4+ T cell proliferation and enhanced their apoptosis, an effect similarly observed in Th0 and Th2 cells, and did not differ between asthmatic children and controls. Conclusion: Our finding that AZM preferentially downregulates IL-5 production suggests its therapeutic potentials in controlling childhood asthma.

MCP‐1 gene regulatory region polymorphism in Chinese children with mild, moderate and near‐fatal asthma

Background:  A polymorphism in the monocyte chemoattractant protein 1 (MCP‐1) gene regulatory region has been associated with asthma in Caucasians. This polymorphism is possibly endemic to the Asian region, but its impact on Asian populations is unclear. In addition, the relationship of this marker with life‐threatening asthma has not been clarified. The aim of this study was to test the genetic association between the MCP‐1 –2518A/G polymorphism and asthma/atopy in a cohort of Chinese children, with particular emphasis on those patients who had experienced life‐threatening asthma attacks.

Effect of azithromycin on natural killer cell function.

Azithromycin (AZM), a macrolide antibiotic for treating mycoplasma infections, may exhibit anti-inflammatory activity aside from its antimicrobial effect, providing additional therapeutic benefit. Natural killer (NK) cells, a first-line innate immune defense against microbial invasions, paradoxically exert a detrimental effect in protecting mycoplasma infection. Little was known regarding the effect of AZM on NK cells. In the present study, we investigated the ability of azithromycin to influence natural killer (NK) cell function with regard to activation, apoptosis and cytotoxic function. AZM had little effect on NK receptor expression and cytotoxic function of NK-92 cells. However, AZM did show a dose-dependent suppression on IL-15-induced CD69 expression of primary NK cells. AZM inhibited the cytotoxicity against K562 cells of resting and IL-15 activated primary NK cells possibly through down-regulation of perforin expression, especially on CD16(+)CD56(+) NK subsets. AZM exerted a dose-dependent inhibition of IFN-gamma and TNF-alpha production from NK-92 cells, but did not affect the cytokine production of IL-15 activated primary NK cells. Taken together, AZM down-regulates NK cytotoxicity and cytokine production and may provide therapeutic benefits aside from its antimicrobial activity.

Umbilical cord blood immunology: relevance to stem cell transplantation.

Because of its easier accessibility and less severe graft-versus-host disease, umbilical cord blood (UCB) has been increasingly used as an alternative to bone marrow for hematopoietic stem cell transplantation. Naiveté of UCB lymphocytes, however, results in delayed immune reconstitution and infection-related mortality in transplant recipients. This review updates the phenotypic and functional deficiencies of various immune cell populations in UCB compared with their adult counterparts and discusses clinical implications and possible therapeutic strategies to improve the outcome of stem cell transplantation.