Cinnamon extract suppresses experimental colitis through modulation of antigen-presenting cells

AIM:To investigate the anti-inflammatory effects of cinnamon extract and elucidate its mechanisms for targeting the function of antigen presenting cells.METHODS:Cinnamon extract was used to treat murine macrophage cell line(Raw 264.7),mouse primary antigen-presenting cells(APCs,MHCII+) and CD11c+dendritic cells to analyze the effects of cinnamon extract on APC function.The mechanisms of action of cinnamon extract on APCs were investigated by analyzing cytokine production,and expression of MHC antigens and co-stimulatory molecules by quantitative real-time PCR and flow cytometry.In addition,the effect of cinnamon extract on antigen presentation capacity and APC-dependent T-cell differentiation were analyzed by [H3]-thymidine incorporation and cytokine analysis,respectively.To confirm the anti-inflammatory effects of cinnamon extract in vivo,cinnamon or PBS was orally administered to mice for 20 d followed by induction of experimental colitis with 2,4,6 trinitrobenzenesulfonic acid.The protective effects of cinnamon extract against experimental colitis were measured by checking clinical symptoms,histological analysis and cytokine expression prof iles in inflamed tissue.RESULTS:Treatment with cinnamon extract inhibited maturation of MHCII+ APCs or CD11c+ dendritic cells(DCs) by suppressing expression of co-stimulatory molecules(B7.1,B7.2,ICOS-L),MHCII and cyclooxygenase(COX)-2.Cinnamon extract induced regulatory DCs(rDCs) that produce low levels of pro-inflammatory cytokines [interleukin(IL)-1β,IL-6,IL-12,interferon(IFN)-γ and tumor necrosis factor(TNF)-α] while expressing high levels of immunoregulatory cytokines(IL-10 and transforming growth factor-β).In addition,rDCs generated by cinnamon extract inhibited APC-dependent T-cell proliferation,and converted CD4+ T cells into IL-10high CD4+ T cells.Furthermore,oral administration of cinnamon extract inhibited development and progression of intestinal colitis by inhibiting expression of COX-2 and pro-inflammatory cytokines(IL-1β,IFN-γ and TNF-α),while enhancing IL-10 levels.CONCLUSION:Our study suggests the potential of cinnamon extract as an anti-inflammatory agent by targeting the generation of regulatory APCs and IL-10+ regulatory T cells.

Adenovirus induced acute hepatitis in non-human primates after liver-directed gene therapy

OBJECTIVE: To define the mechanism of acute hepatitis in non-human primates after liver directed gene therapy. METHODS: Differences in immune response exhibited by 8 rhesus monkeys receiving adenovirus (Ad) or lipofectamine-mediated gene transfer by various routes, the time course, and the nature of the specific immune responses to both adenoviral vectors and transgene products were studied using HE staining (H&E) and immunohistochemical staining. RESULTS: The monkeys developed mild to moderate acute hepatitis 1 to 3 weeks after intravenous or intrabiliary injection of first generation replication-defective adenoviruses carrying the Escherichia coli lacZ gene. This was accompanied by adenovirus-mediated T-cell proliferation and neutralizing antibodies to the adenovirus. Increased numbers of CD3(+), CD4(+) and CD8(+) T-lymphocytes were detected in the diseased livers, while B-lymphocytes were absent. Hepatocytes demonstrated increased expression of beta 2-microglobulins (beta 2-MG) and HLA-DR antigens in the plasma membranes. The development of acute hepatitis and the accompanying immune abnormalities were delayed in immunosuppressed monkeys until after the discontinuation of immunosuppressive therapy. The monkeys infused with Ad. CMVluc showed more significant and longer durations of hepatitis than the monkeys infused with adenoviruses carrying the lacZ gene. Lipofectamine-mediated gene transfer was inefficient. There was neither lacZ expression nor significant immune response in the liver of monkeys infused with lipofectamine via the portal vein or the common bile duct. CONCLUSION: Immune response to the hepatocytes in liver directed gene therapy is MHC class I restricted and T-cell mediated. Both adenoviral vectors and foreign genes are related to the liver damage. Mild to moderate hepatic inflammation seen with the E-1 deleted vector is reversible. Immunosuppression regimens may prolong transgene expression and delay the development of acute adenoviral hepatitis.