Xiaohui Ji

Serum IL-10 from systemic lupus erythematosus patients suppresses the differentiation and function of monocyte-derived dendritic cells

The role played by cytokines, other than interferon (IFN)-α, in the differentiation and function of dendritic cells (DCs) in systemic lupus erythematosus (SLE), remains unclear. Serum interleukin-10 (IL-10) levels are generally elevated in SLE patients, which might modulate the differentiation of DCs. In this study, DCs were induced from monocytes either by transendothelial trafficking or by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) + IL-4 + tumor necrosis factor (TNF)-α. Both systems were used to investigate the effects of elevated serum IL-10 level on DC differentiation in SLE patients. The results showed that monocyte-derived DCs induced by either SLE serum or exogenous IL-10 reduced the expression of human leukocyte antigen (HLA)-DR and CD80, decreased IL-12p40 level, and increased IL-10 level, and exhibited an impaired capacity to stimulate allogenic T-cell proliferation. These results indicate that serum IL-10 may be involved in the pathogenesis of SLE by modulating the differentiation and function of DCs.

Interferon-α and Interleukin-6 in SLE serum induce the differentiation and maturation of dendritic cells derived from CD34+ hematopoietic precursor cells

The objective of this study was to investigate the effects of the cytokines IFN-alpha, IL-6 and IL-10 present in the serum of systemic lupus erythematosus (SLE) patients on the differentiation and maturation of DCs derived from CD34(+) hematopoietic precursor cells (HPCs). CD34(+) HPCs cultured in SLE serum containing elevated levels of IFN-alpha or IL-6 differentiated into DCs showing an increased expression of HLA-DR, CD80 and CD86, decreased IL-12 secretion along with increased IL-10 production, and an increased ability to stimulate allogenic T-cell proliferation, compared with DCs cultured in normal serum. DCs cultured with high levels of IFN-alpha increased the proportion of both CD3(+)CD8(-)IFN-gamma(+) and CD3(+)CD8(+)IFN-gamma(+) T-cell subsets, and increased the production of IFN-gamma in the allogenic MLR. DCs cultured with high levels of IL-6 decreased the proportion of both IFN-gamma(+) T-cell subsets, and decreased the secretion of IFN-gamma, but increased the production of IL-10. The IL-10 present in SLE serum did not significantly alter the phenotype or function of the DCs. IFN-alpha and IL-6 present in SLE serum induce CD34(+) HPCs to differentiate into DCs with different regulatory effects on T-cell differentiation, which might be involved in the initiation and maintenance of SLE.

Increased serum IL-10 in lupus patients promotes apoptosis of T cell subsets via the caspase 8 pathway initiated by Fas signaling.

Abstract We sought to investigate the expression of Fas and FasL on T cell surface and caspase 8 involvement in T cell apoptosis promoted by serum IL-10 in systemic lupus erythematosus (SLE) patients. Cells and sera were obtained from 35 SLE patients. Apoptosis of T cells in patients with SLE was increased and associated with the SLE disease activity index (SLEDAI). Elevated expression of Fas and FasL on T cell surface contributed to increased apoptosis of T cells. Increased IL-10 in the sera of SLE patients was capable of inducing Fas and FasL expression on CD4+T cell surface, promoting apoptosis of this cell subset. Decreased IL-10 serum levels and low expression of Fas were found in 5 patients of the first follow-up group after 2-month treatment. In another group with one-year treatment, the SLEDAI declined to inactive scores. Serum IL-10 was decreased significantly, and expression of Fas and FasL on T cells was also reduced. Declined apoptosis was predominant only in CD4+T cell subset. When sera with high level of IL-10 were used to culture PBMCs from healthy controls, activated caspase 8 was elevated in CD3+T, CD4+T and CD8+T cells. The study showed that serum IL-10 induced apoptosis of T cell subsets via the caspase 8 pathway initiated by Fas signaling. Increased apoptosis of T cells contributes to autoantigen burden, which is pathogenic in the development of SLE.

Targeted NF-κB inhibition of asthmatic serum-mediated human monocyte-derived dendritic cell differentiation in a transendothelial trafficking model

Transendothelial trafficking model mimics in vivo differentiation of monocytes into dendritic cells (DC). The serum from patients with systemic lupus erythematosus promotes the differentiation of monocytes into mature DC. We have shown that selective inhibition of NF-kappaB by adenoviral gene transfer of a novel mutated IkappaBalpha (AdIkappaBalphaM) in DC contributes to T cell tolerance. Here we demonstrated for the first time that asthmatic serum facilitated human monocyte-derived DC (MDDC) maturation associated with increased NF-kappaB activation in this model. Furthermore, selective blockade of NF-kappaB by AdIkappaBalphaM in MDDC led to increased apoptosis, and decreased levels of CD80, CD83, CD86, and IL-12 p70 but not IL-10 in asthmatic serum-stimulated MDDC, accompanied by reduced proliferation of T cells. These results suggest that AdIkappaBalphaM-transferred MDDC are at a more immature stage which is beneficial to augment the immune tolerance in asthma.

Role of interleukin 17 in TGF-β signaling-mediated renal interstitial fibrosis

Background Several studies suggest IL‐17 is involved in the pathogenesis of organ fibrosis. The exact role of IL‐17 in renal interstitial fibrosis has not been fully elucidated. Methods We compared the histopathology of renal fibrosis as well as profibrotic TGF‐&bgr; signaling in wild‐type (WT) and IL‐17 knock‐out (IL‐17−/−) mice using UUO as the disease model. To find out the possible mechanisms involved in the exacerbated renal fibrosis happened to IL‐17−/− mice, we analyzed the pattern of ECM synthesis by different fibroblasts cultured with IL‐17 and associated signaling mediators. Results On day3 and day7, IL‐17−/− mice developed more severe renal fibrosis compared with WT mice. IL‐17 had an inhibitory factor in TGF‐&bgr;‐induced renal fibroblast activation and ECM synthesis, and sequentially in renal interstitial fibrosis, via down‐regulation of Smad ‐independent pathway (p38MAPK and AKT phosphorylations). Conclusion IL‐17 acts an inhibitory factor in TGF‐&bgr;‐induced renal fibroblast activation and ECM synthesis, and sequentially in renal interstitial fibrosis, via down‐regulation of Smad‐independent pathway (p38MAPK and AKT phosphorylations). Clarifying the novel regulatory mechanisms of fibrosis by the cytokine IL‐17 may lead to a new therapeutic approach for progressive renal disease and fibrosis.

Lactobacillus isolates from healthy volunteers exert immunomodulatory effects on activated peripheral blood mononuclear cells

As probiotics in the gut, Lactobacilli are believed to play important roles in the development and maintenance of both the mucosal and systemic immune system of the host. This study was aimed to investigate the immuno-modulatory function of candiate lactobacilli on T cells. Lactobacilli were isolated from healthy human feces and the microbiological characteristics were identified by API 50 CHL and randomly amplified polymorphic DNA (RAPD) assays. Anti-CD3 antibody activated peripheral blood mononuclear cells (PBMCs) were treated by viable, heat-killed lactobacilli and genomic DNA of lactobacilli, and cytokine profiles were tested by ELISA. Isolated lactobacilli C44 and C48 were identified as L. acidophilus and L. paracacei, which have properties of acid and bile tolerance and inhibitor effects on pathogens. Viable and heat-killed C44 and C48 induced low levels of proinflammatory cytokines (TNF-α, IL-6 and IL-8) and high levels of IFN-γ and IL-12p70 in PBMCs. In anti-CD3 antibody activated PBMCs, viable and heat-killed C44 increased Th2 cytokine levels (IL-5, IL-6 and IL-10), and simultaneously enhanced Th1 responses by inducing IFN-γ and IL-12p70 production. Different from that of lactabacillus strains, their genomic DNA induced low levels of IL-12p70, IFN-γ and proinflammatory cytokines in PBMCs with or without anti-CD3 antibody activation. These results provided in vitro evidence that the genomic DNA of strains of C44 and C48, especially C44, induced weaker inflammation, and may be potentially applied for treating allergic diseases.

Hesperetin inhibits the maturation and function of monocyte-derived dendritic cells from patients with asthma.

Dendritic cells (DCs) are crucial regulators of allergic diseases. Hesperetin, an important bioactive compound in Chinese traditional medicine, has antioxidant and anti-allergic properties. In this study, we examined whether hesperetin influences surface molecule expression, cytokine production, the capacity to induce T cell proliferation, and the underlying signaling pathway in monocyte-derived DCs from patients with allergic asthma. The results show that hesperetin significantly suppressed Der p 1-induced HLA-DR, CD86 and CD83 expression in DCs. However, the secretion of IL-10 was not affected. Hesperetin-treated DCs exhibited a reduced ability to stimulate autologous CD4+ T cells, accompanied by less Th2 polarization. In addition, the Der p 1-induced phosphorylation of IκBα and the translocation of NF-κB p65 were inhibited in the presence of hesperetin. These novel findings provide insight into the immunopharmacological role of hesperetin in DC-based allergic diseases.

Role of decidual CD14+ macrophages in the homeostasis of maternal–fetal interface and the differentiation capacity of the cells during pregnancy and parturition

OBJECTIVE Decidual macrophages (dMΦs) have been implicated in fetal tolerance, but little information is known regarding their differentiation capacity and interactions with T cells. The present study aimed to investigate the immunological characteristics of dMΦs at mid and term pregnancy. METHODS The dMΦs were analyzed for their phenotypes and cytokine production by flow cytometry and ELISA, respectively. The transendothelial trafficking model was implemented to allow the dMΦs to differentiate. The differentiated cells from dMΦs were also measured for their phenotypes and cytokine production with same methods. The capacity of dMΦs or the differentiated cells from dMΦs to stimulate allogeneic T lymphocyte proliferation was evaluated by T lymphocyte stimulation assays. T cell differentiation was determined by flow cytometry. RESULTS The dMΦs in the mid-pregnancy (Mid-dMΦs) resembled the M2 phenotype. The differentiated cells from Mid-dMΦs had little stimulatory capacity on T cell proliferation and favored regulatory T cell differentiation. The dMΦs at term differentiated into dendritic (DC)-like cells, stimulating T cell activation, proliferation, and differentiation into IFN-γ-producing T cellsdecidual CONCLUSIONS The present study suggests that the differences in phenotypes and cytokine production between Mid- and Term-dMΦs relate to their different roles in the homeostasis of the maternal-fetal interface. Mid-dMΦs differentiate into DC-like cells with immunosuppressive properties, playing an important role in maintaining homeostasis required for a successful pregnancy. Term-dMΦs differentiate into DC-like cells with immunostimulatory properties, likely involved in the activation of labor. The different differentiation capacities of dMΦs in the varied pregnancy stages may be due to the placental microenvironment.

The Effects of the Recombinant CCR5 T4 Lysozyme Fusion Protein on HIV-1 Infection

Background Insertion of T4 lysozyme (T4L) into the GPCR successfully enhanced GPCR protein stability and solubilization. However, the biological functions of the recombinant GPCR protein have not been analyzed. Methods We engineered the CCR5-T4L mutant and expressed and purified the soluble recombinant protein using an E.coli expression system. The antiviral effects of this recombinant protein in THP-1 cell lines, primary human macrophages, and PBMCs from different donors were investigated. We also explored the possible mechanisms underlying the observed antiviral effects. Results Our data showed the biphasic inhibitory and promotion effects of different concentrations of soluble recombinant CCR5-T4L protein on R5 tropic human immunodeficiency virus-1 (HIV-1) infection in THP-1 cell lines, human macrophages, and PBMCs from clinical isolates. We demonstrated that soluble recombinant CCR5-T4L acts as a HIV-1 co-receptor, interacts with wild type CCR5, down-regulates the surface CCR5 expression in human macrophages, and interacts with CCL5 to inhibit macrophage migration. Using binding assays, we further determined that recombinant CCR5-T4L and [125I]-CCL5 compete for the same binding site on wild type CCR5. Conclusions Our results suggest that recombinant CCR5-T4L protein marginally promotes HIV-1 infection at low concentrations and markedly inhibits infection at higher concentrations. This recombinant protein may be helpful in the future development of anti-HIV-1 therapeutic agents.

Sinomenine reduces iNOS expression via inhibiting the T-bet IFN-γ pathway in experimental autoimmune encephalomyelitis in rats.

Sinomenine is a bioactive alkaloid isolated from the Chinese medicinal plant Sinomenium acutum. It is widely used as an immunosuppressive drug for treating rheumatic and arthritic diseases. In our previous studies, we found that sinomenine reduced cellular infiltration within the spinal cord and alleviated experimental autoimmune encephalomyelitis (EAE) in rats. In this study, we further investigated the mechanisms of sinomenine treatment in EAE rats. In EAE rats, treatment with sinomenine exerted an anti-inducible NO synthase (anti-iNOS) effect, which is related to the reductions of Th1 cytokine interferon-γ (IFN-γ) and its transcription factor, T-bet, in spinal cords. Moreover, sinomenine treatment of splenocytes stimulated with anti-CD3 antibody and recombinant rat interleukin 12 reduced the expression of T-bet and IFN-γ in vitro and also reduced the capability of supernatants of splenocyte culture to induce iNOS expression by primary astrocytes. However, sinomenine had no direct inhibitory effect on iNOS produced by astrocytes cultured with IFN-γ and tumor necrosis factor α in vitro. In conclusion, the anti-iNOS effect of sinomenine on EAE is mediated via the suppression of T-bet /IFN-γ pathway.