RESUMEN
Objective To study the mechanism of Sanhuang Decotion in the treatment of ulcerative colitis(UC)under Candida albicans colonization in mice based on Dectin-1-Syk-CARD9 signaling pathway.Methods Mice model of UC with fungal colonization were established with dextran sodium sulfate free drinking and C.albicans intragastric administration.Mice were divided into normal control group,model group,sulfasalazine group,fluconazole group,and Sanhuang Decotion low-and high-dosage groups,and receive corresponding drug interventions.General state of mice were observed,and the disease activity index(DAI)score of mice were calculated.The load of C.albicans in intestine was detected,the length of the colon was measured,and pathological scoring of the colon tissue was performed.The ultrastructural changes of colon epithelium were observed under transmission electron microscopy.The contents of TNF-α,IL-6 and IL-12 in serum and colon tissues were detected by ELISA.The mRNA and protein expression of Dectin-1,Syk,CARD9,NF-κBp65 and inflammation factors in intestinal epithelial cells and colon tissues were detected by qPCR,Western blot and immunohistochemistry.Results Compared with the normal control group,the model group mice showed reduced activity,decreased food intake,accompanied by loose stools,significantly increased DAI score,increased load of C.albicans in the intestine,shortened colon length,and increased histopathological score,with widening of gap between colon epithelial cells,cytoplasmic dissolution,mitochondrial swelling;TNF-α,IL-6 and IL-12 in serum and colon tissue increased,the expressions of Dectin-1 and CARD9 mRNA and protein in colon epithelial cells increased,p-Syk,p-NF-κBp65,CARD9,TNF-α,IL-1β,IL-6 protein expression in colon tissue increased(P<0.01,P<0.05).Compared with the model group,the Sanhuang Decotion high-dosage group mice showed a significant decrease in DAI score,decreased intestinal C.albicans load,increased colon length,decreased histopathological score,more complete and orderly arrangement of microvilli in colon epithelial cells,mild mitochondrial swelling,TNF-α,IL-6 and IL-12 in serum and colon tissue decreased,and the mRNA and protein expression of Dectin-1 and CARD9 in colon tissue increased,the expression of p-Syk,p-NF-κBp65,CARD9,TNF-α,IL-1β,IL-6 protein in colon tissue decreased(P<0.01,P<0.05).Conclusion Sanhuang Decotion may exert an anti C.albicans colonization UC effect by inhibiting the Dectin-1-Syk-CARD9 signaling pathway and reducing the release of inflammatory factors.
RESUMEN
Objective To study the mechanism of adaptive immunity against Rhizopus arrihizus (R. arrihizus) infections. Methods Bone marrow derived dendritic cells (BMDCs) were separated from C57BL/6 mice and Card9-/- mice and then were cultured in vitro. Resting spores and swollen spores of R. arrihizus were in vitro co-cultured with BMDCs with or without Syk inhibition. Secretion of cytokines ( IL-23, IL-1βand IL-12) was analyzed by ELISA after 24 hours of culture. Na?ve T cells derived from C57BL/6 mice were in vitro co-cultured with spore-stimulated BMDCs for four days. Levels of IL-17A and IFN-γ in supernatants of cell culture were analyzed by ELISA. Flow cytometry was performed to analyze T cell differ-entiation. Confocal microscopy was used to observe the images of stained β-glucan on the surface of resting and swollen spores. Swollen spores were co-cultured with Dectin-1, Dectin-2, TLR2 and mannose receptor ( MMR) , and the binding results were analyzed by flow cytometry. Results Swollen spores but resting spores could induce the maturation of BMDCs and promote the secretion of cytokines (IL-23, IL-1βand IL-12). Co-culturing T cells with swollen spore-stimulated BMDCs enhanced their differentiation to Th17 and Th1. In addition, swollen spores promoted the secretion of Th1-related cytokine ( IFN-γ) and Th17-related cytokine (IL-17A). Adding Syk inhibitor to Card9-/-BMDCs or wild type BMDCs significantly inhibited the secretion of cytokines and T cell differentiation, especially in the Card9-/- group. β-glucan was overserved on the surface of swollen spores, but not on resting spores. On the surface of swollen spores existed pathogen associated molecular patterns ( PAMPs) that could bind with Dectin-1 and TLR2. Conclusion Swollen spores of R. arrihizus could active BMDCs to secrete cytokines of IL-23, IL-1β and IL-12 and trigger T cell responses in vitro. The possible mechanism might be associated with β-glucan exposed on the surface of swollen spores that binds with Dectin-1. The responses between BMDCs and R. arrihizus are Syk-Card9-dependent.