Project description:The goal of this study is to investigate the involvement of inflammation in Alzheimer’s disease (AD) and to clarify the signaling pathways involved in the presence of beta-amyloidosis, a hallmark of AD pathogenesis, to help identifying potential targets for therapy. To do that, we isolated bone marrow-derived progenitor cells from femurs, tibiae and hip bones of non-transgenic C57BL/6 mice according to established protocols , and we maturated them with LPS. To obtain an unbiased view of gene regulation in mouse bone marrow-derived dendritic cells (BM-DCs) exposed to pre-aggregated beta-amyloid peptide (Aβ) oligomers, we analyzed the transcriptome of untreated immature control BM-DCs (‘Ctrl’), LPS-treated BM-DCs (’LPS’), Aβ1-42 oligomer-treated BM-DCs (‘Aβ‘) and BM-DCs treated with Aβ1-42 oligomers and LPS (‘Aβ+LPS‘) via explorative RNA-sequencing.
Project description:The infiltration of effector CD8+ T cells into tumors is one of the major predictors of clinical outcome for epithelial ovarian cancer (EOC) patients. Immune cell infiltration is a complex process that could be affected by the epigenetic makeup of the tumor. Here, we demonstrate that a lysine 4 histone H3 (H3K4) demethylase KDM5A impairs immune cell infiltration and inhibits anti-tumor immune response. Mechanistically, KDM5A silences genes involved in antigen processing and presentation pathway. Antigen processing and presentation is a critical step that is required for CD8+ T cells infiltration and activation of CD8+ T cell mediated anti-tumor immune response. KDM5A inhibition restores the expression of antigen presentation pathway in vitro and promotes anti-tumor immune response mediated by CD8+ T cells in vivo in a syngeneic EOC mouse model. Notably, a negative correlation between expression of KDM5A and genes involved in antigen processing and presentation pathway such as HLA-A and HLA-B is observed in the majority of cancer types. In summary, our results establish KDM5A as a regulator of CD8+ T cells tumor infiltration and demonstrate that KDM5A inhibition is a novel therapeutic strategy aiming to boost anti-tumor immune response.
Project description:The infiltration of effector CD8+ T cells into tumors is one of the major predictors of clinical outcome for epithelial ovarian cancer (EOC) patients. Immune cell infiltration is a complex process that could be affected by the epigenetic makeup of the tumor. Here, we demonstrate that a lysine 4 histone H3 (H3K4) demethylase KDM5A impairs immune cell infiltration and inhibits anti-tumor immune response. Mechanistically, KDM5A silences genes involved in antigen processing and presentation pathway. Antigen processing and presentation is a critical step that is required for CD8+ T cells infiltration and activation of CD8+ T cell mediated anti-tumor immune response. KDM5A inhibition restores the expression of antigen presentation pathway in vitro and promotes anti-tumor immune response mediated by CD8+ T cells in vivo in a syngeneic EOC mouse model. Notably, a negative correlation between expression of KDM5A and genes involved in antigen processing and presentation pathway such as HLA-A and HLA-B is observed in the majority of cancer types. In summary, our results establish KDM5A as a regulator of CD8+ T cells tumor infiltration and demonstrate that KDM5A inhibition is a novel therapeutic strategy aiming to boost anti-tumor immune response.
Project description:Increased antigen cross-presentation but impaired cross-priming after activation of PPARγ is mediated by up-regulation of B7H1 Dendritic cells (DCs) are able to take up exogenous antigens and present antigen-derived peptides on MHC class I molecules, a process termed cross-presentation. The mannose receptor (MR), an endocytic receptor expressed on a variety of antigen-presenting cells (APCs), has been demonstrated to target soluble antigens exclusively towards cross-presentation. In this study, we investigated the role of the murine nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated transcription factor with immunomodulatory properties, in MR-mediated endocytosis and cross-presentation of the model antigen ovalbumin (OVA). We could demonstrate both in vitro and in vivo that activation of PPARγ resulted in increased MR expression, which in consequence led to enhanced MR-mediated endocytosis and elevated cross-presentation of soluble OVA. Concomitantly, activation of PPARγ in DCs induced up-regulation of the co-inhibitory molecule B7H1, which, despite enhanced cross-presentation, caused an impaired activation of naive OVA-specific CD8+ T cells and the induction of T cell tolerance. These data provide a mechanistic basis for the immunomodulatory action of PPARγ which might open new possibilities in development of therapeutical approaches aimed at the control of excessive immune responses, e.g. in T cell-mediated autoimmunity. Comparison of murine mannose receptor negative versus mannose receptor positive bone marrow-derived DCs
Project description:CD8+ T cells contribute to protective immunity to Mycobacterium tuberculosis (Mtb), but the principles that govern presentation of Mtb peptides on MHC class I (MHC-I) on the surface of infected macrophages for CD8+ T cell recognition are incompletely understood. Here, we use internal standard parallel reaction monitoring (IS-PRM, also known as SureQuant) to rigorously validate identifications of Mtb-derived MHC-I peptides obtained in data-dependent MS analyses. We further use SureQuant to quantify presentation of Mtb peptides derived from the secreted effector proteins EsxA and EsxJ across multiple experimental conditions. We show that presentation of both EsxA- and EsxJ-derived peptides requires the activity of the mycobacterial ESX-1 type VII secretion system, possibly indicating that ESX-1-mediated phagosome membrane damage allows Mtb proteins to access MHC-I antigen processing pathways. We show that this requirement is independent of type I interferon signaling that occurs downstream of phagosome damage. Treatment with inhibitors of conventional proteolytic pathways involved in MHC-I antigen processing inhibits presentation of self peptides as expected, but does not inhibit presentation of Mtb peptides, implying an alternative or redundant mechanism of processing.
Project description:Increased antigen cross-presentation but impaired cross-priming after activation of PPARγ is mediated by up-regulation of B7H1 Dendritic cells (DCs) are able to take up exogenous antigens and present antigen-derived peptides on MHC class I molecules, a process termed cross-presentation. The mannose receptor (MR), an endocytic receptor expressed on a variety of antigen-presenting cells (APCs), has been demonstrated to target soluble antigens exclusively towards cross-presentation. In this study, we investigated the role of the murine nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated transcription factor with immunomodulatory properties, in MR-mediated endocytosis and cross-presentation of the model antigen ovalbumin (OVA). We could demonstrate both in vitro and in vivo that activation of PPARγ resulted in increased MR expression, which in consequence led to enhanced MR-mediated endocytosis and elevated cross-presentation of soluble OVA. Concomitantly, activation of PPARγ in DCs induced up-regulation of the co-inhibitory molecule B7H1, which, despite enhanced cross-presentation, caused an impaired activation of naive OVA-specific CD8+ T cells and the induction of T cell tolerance. These data provide a mechanistic basis for the immunomodulatory action of PPARγ which might open new possibilities in development of therapeutical approaches aimed at the control of excessive immune responses, e.g. in T cell-mediated autoimmunity.
Project description:Current cancer immunotherapies are assumed to improve infiltration and cytotoxicity of immune cells in the tumor. However, tumor cells have developed a variety of resistance mechanisms to suppress the MHC class I antigen presentation, and thereby impair the cytotoxicity of CD8+ T cells. Here, we identified Mal2 as a key player that mediates the turnover of the antigen-MHC-I complex and reduce the antigen presentation on tumor cells. Mal2 promotes the endocytosis of tumor antigen via direct interaction with the MHC-I complex and endosome-associated Rab5/7. In mouse and human breast tumor models, inhibition of Mal2 profoundly enhanced the cytotoxicity of tumor-infiltrating CD8+ T cells and suppressed breast tumor growth, suggesting that Mal2 is a potential target for breast cancer immunotherapy.