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Down-regulation of TLR9 expression affects the maturation and function of murine bone marrow-derived dendritic cells induced by CpG.

ABSTRACT: Toll-like receptor 9 (TLR9) is expressed intracellularly by dendritic cells (DCs) and specifically recognizes unmethylated CpG motif. Recognition of TLR9 to CpG DNA can induce DC maturation followed by the subsequent immune responses. Here, RNA interference (RNAi) was used to identify the effect of CpG DNA signaling on DC function. The results showed that transfection of DCs with siRNA specific for TLR9 gene significantly down-regulated TLR9 expression. Immature DCs transfected with TLR9 siRNA did not differentiate into mature DCs with exposure to CpG. TLR9 siRNA-treated DCs expressed low levels of MHC II and CD40 without reducing endocytosis. Furthermore, TLR9 siRNA-transfected DCs exhibited a decreased allostimulatory capacity in a lymphocyte proliferation assay and attenuated Th1 responses by decreasing IL-12p70 production. Our findings indicate that siRNA in silencing TLR9 gene in DCs may offer a potential tool to study the TLR9-CpG pathway.

SUBMITTER: Ma L

PROVIDER: S-EPMC4003063 | biostudies-other | 2009 Jun

REPOSITORIES: biostudies-other

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Down-regulation of TLR9 expression affects the maturation and function of murine bone marrow-derived dendritic cells induced by CpG.

Ma Ling L Zhao Guangfeng G Hua Chunyan C Li Xiaoxi X Zhao Xiaoyin X Sun Lingyun L Hou Yayi Y

Cellular & molecular immunology 20090601 3

Toll-like receptor 9 (TLR9) is expressed intracellularly by dendritic cells (DCs) and specifically recognizes unmethylated CpG motif. Recognition of TLR9 to CpG DNA can induce DC maturation followed by the subsequent immune responses. Here, RNA interference (RNAi) was used to identify the effect of CpG DNA signaling on DC function. The results showed that transfection of DCs with siRNA specific for TLR9 gene significantly down-regulated TLR9 expression. Immature DCs transfected with TLR9 siRNA d ...[more]

PMID: 19567203

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Project description:Research in chickens has been fundamental for the discovery of basic aspects of the immune system and has led to an interest in the in-depth characterization of avian immune cell types including dendritic cells (DCs). The in vitro generation and expansion of chicken bone marrow-derived DCs (chBMDCs) in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) has provided a way to study chicken DCs, which are only present at limited cell numbers in vivo. This method has been employed to study the interactions between chicken DCs and pathogens or vaccines. However, a detailed characterization of the chBMDC culture is still lacking. In the present study, we performed an elaborate phenotypical and functional analysis of the chBMDC culture and addressed its heterogeneity. After 8 days of culture, chBMDCs comprised major histocompatibility complex class II (MHC-II)low and MHC-IIhigh subsets with different morphologies. Compared with MHC-IIlow chBMDCs, the MHC-IIhigh subset showed a more mature phenotype, with higher expressions of CD1.1, CD40, CD80, CCR7, and CD83, and a relatively low opsonophagocytic capacity. Nevertheless, MHC-IIhigh chBMDCs did not show an increased capacity to induce T-cell proliferation. Therefore, MHC-IIhigh chBMDCs were found to be semi-mature. Interestingly, the presence of the semi-mature MHC-IIhigh chBMDC subset reduced when cells were cultured in the presence of IL-4. Finally, prolonged cell culture after fluorescence-activated cell sorting (FACS) converted the semi-mature MHC-IIhigh subset back into the immature phenotype of the MHC-IIlow subset, demonstrating plasticity of their maturation state. This detailed characterization explained the heterogeneity of the chBMDC culture by the simultaneous presence of immature and semi-mature chBMDC subsets, in addition to cells without features of antigen-presenting cells. Our findings are instrumental for the interpretation of experiments using the chBMDC culture in past and future research by providing insights into its phenotypically and functionally distinct cell types.

Dataset Information

Down-regulation of TLR9 expression affects the maturation and function of murine bone marrow-derived dendritic cells induced by CpG.

Publications

Down-regulation of TLR9 expression affects the maturation and function of murine bone marrow-derived dendritic cells induced by CpG.

Similar Datasets

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