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Abstract: Dendritic cells (DC) excel at presenting antigen to T cells and thus make a key contribution to the induction of primary and secondary immune responses. Sinomenine has been used for centuries in the treatment of patients with autoimmune diseases as it possesses immunosuppressive and anti-inflammatory activities. However, the effect of sinomenine on the differentiation, maturation, and functionality of DC derived from monocytes has not been studied. We show here that DC differentiation is promoted when monocytes are treated with GM-CSF and IL-4 (IL-4) in the presence of sinomenine (200 μg/ml), as evidenced by the upregulation of CD1a while CD14 was decreased. In addition, incubation of immature DC with sinomenine significantly blunted lipopolysaccharide (LPS)-induced DC maturation, as shown by the reduction of expression of the maturation marker CD83 and co-stimulatory molecules, including CD86, B7-H1, and CD40. Moreover, sinomenine also prevented decreases in antigen (FITC-Dextran or Lucifer Yellow) uptake by LPS-treated DC. Mixed lymphocyte reactions (MLRs) revealed that sinomenine-treated DC impede the secretion of the cytokines IL-2 and IFN-γ by co-cultured CD4+ T cells. Therefore, modulation of DC differentiation, maturation, and functionality by sinomenine is of potential relevance to its immunomodulatory effects in controlling specific immune responses in autoimmune diseases, transplantation, and other immune-mediated conditions. [Copyright &y& Elsevier]

Abstract: The co-inhibitory molecule B7-H1 has been broadly detectable on human inflammatory renal tubular epithelial cells (TECs) and is proposed to limit tubular damage through down-regulation of tubulointerstitial infiltration T cell activation. Nevertheless, factors that initiate B7-H1 expression on TECs remain unclarified. The terminal complement complex C5b-9, which deposits diffusely on tubules and glomerules of diseased kidneys, is now recognized as a mediator that triggers cellular activation rather than inducing cell death. Whether the up-regulation of B7-H1 on tubules is also induced by C5b-9 is uncertain. Here, after assembling functional sublytic C5b-9 on the membranes of TECs based on purified complement components, we found that B7-H1 gene transcription and protein synthesis was enhanced by C5b-9. Promoter constructs in a luciferase assay, site-directed mutagenesis and laser scanning confocal microscopy assay (LSCM) revealed that the transcription factor NF-κB is primarily responsible for C5b-9-mediated B7-H1 expression. To further detect the physiologic function of B7-H1, triggering B7-H1 with its agonist mAb (clone 5H1) profoundly enhanced Fas expression on C5b-9-treated TECs and thus induced TEC apoptosis. Interestingly, pretreatment of TECs with Fas blocking antibodies prevented this effect. Our results propose that C5b-9 regulates tubular pathogenesis in glomerulonephritis or other renal autoimmune diseases, possibly through enhances cell apoptosis mediated by B7-H1 signals, in addition to it directly promotes tubular damage. [Copyright &y& Elsevier]