Project description:The innate immune system plays an essential role in regulating the immune responses to kidney transplantation, but the mechanisms through which innate immune cells influence long-term graft survival are unclear. The current study highlights the vital role of trained immunity in kidney allograft survival. Trained immunity describes the epigenetic and metabolic changes that innate immune cells undergo following an initial stimulus, allowing them have a stronger inflammatory response to subsequent stimuli. We stimulated healthy peripheral blood mononuclear cells with pretransplant and posttransplant serum of kidney transplant patients and immunosuppressive drugs in an in vitro trained immunity assay and measured tumor necrosis factor and interleukin 6 cytokine levels in the supernatant as a readout for trained immunity. We show that the serum of kidney transplant recipients collected 1 week after transplantation can suppress trained immunity. Importantly, we found that kidney transplant recipients whose serum most strongly suppressed trained immunity rarely experienced graft loss. This suppressive effect of posttransplant serum is likely mediated by previously unreported effects of immunosuppressive drugs. Our findings provide mechanistic insights into the role of innate immunity in kidney allograft survival, uncovering trained immunity as a potential therapeutic target for improving graft survival.
Project description:The innate immune system plays an essential role in regulating the immune responses to kidney transplantation, but the mechanisms through which innate immune cells influence long-term graft survival are unclear. The current study highlights the vital role of trained immunity in kidney allograft survival. Trained immunity describes the epigenetic and metabolic changes that innate immune cells undergo following an initial stimulus, allowing them have a stronger inflammatory response to subsequent stimuli. We stimulated healthy peripheral blood mononuclear cells with pretransplant and posttransplant serum of kidney transplant patients and immunosuppressive drugs in an in vitro trained immunity assay and measured tumor necrosis factor and interleukin 6 cytokine levels in the supernatant as a readout for trained immunity. We show that the serum of kidney transplant recipients collected 1 week after transplantation can suppress trained immunity. Importantly, we found that kidney transplant recipients whose serum most strongly suppressed trained immunity rarely experienced graft loss. This suppressive effect of posttransplant serum is likely mediated by previously unreported effects of immunosuppressive drugs. Our findings provide mechanistic insights into the role of innate immunity in kidney allograft survival, uncovering trained immunity as a potential therapeutic target for improving graft survival.
Project description:Recent studies have demonstrated that both mouse and human alpha beta TCR(+)CD3(+)NK1.1(-)CD4(-)CD8- double-negative regulatory T (DN Treg) cells can suppress Ag-specific immune responses mediated by CD8+ and CD4+ T cells. To identify molecules involved in DN Treg cell function, we generated a panel of murine DN Treg clones, which specifically kill activated syngeneic CD8+ T cells. Through serial cultivation of DN Treg clones, mutant clones arose that lost regulatory capacity in vitro and in vivo. Although all allogeneic cardiac grafts in animals preinfused with tolerant CD4/CD8 negative 12 DN Treg clones survived over 100 days, allograft survival is unchanged following infusion of mutant clones (19.5 +/- 11.1 days) compared with untreated controls (22.8 +/- 10.5 days; p < 0.001). Global gene expression differences between functional DN Treg cells and nonfunctional mutants were compared. We found 1099 differentially expressed genes (q < 0.025%), suggesting increased cell proliferation and survival, immune regulation, and chemotaxis, together with decreased expression of genes for Ag presentation, apoptosis, and protein phosphatases involved in signal transduction. Expression of 33 overexpressed and 24 underexpressed genes were confirmed using quantitative real-time PCR. Protein expression of several genes, including Fc epsilon RI gamma subunit and CXCR5, which are >50-fold higher, was also confirmed using FACS. These findings shed light on the mechanisms by which DN Treg cells down-regulate immune responses and prolong cardiac allograft survival. Type 2 experiment where functional DN T-reg cells (CN4 or TN12) were cy-3 labeled and co-hybridized with non-functional mutant cell lines (CN4.8 or CN12.8). Used 100 ug total-RNA each channel and no amplifaction. A transcript identification design type characterizes the length and position of transcripts and allows identification of all forms of transcripts in the genome. Using regression correlation
Project description:Trained immunity refers to epigenetic and metabolic changes in innate immune cells following exposure to inflammatory signals, leading to a heightened response to secondary stimuli. Although this innate immune memory contributes to host defense against infections, it can also have maladaptive consequences in a broad range of immune-driven conditions. During the past decade, we have gained an increasingly better understanding of the molecular regulation of trained immunity, but the role of adaptive immune cells in modulation of trained immunity remains largely unknown. Here, we show that T cell interactions contribute to the induction of trained immunity in monocytes and that this mediated by CD40-TRAF6 signaling. Specifically, we found that inhibiting CD40-TRAF6 signaling prevents the induction of functional, transcriptomic, metabolic and epigenetic changes associated with trained immunity. Apart from detailed in vitro studies, we inhibited CD40-TRAF6 signaling in vivo in myeloid cells in a murine heart transplantation model which resulted in prolonged allograft survival. When the animals were additionally treated with costimulatory blockade by CTLA4-Ig, we observed immunological tolerance to the graft. Combined, our study reveals that trained immunity induction is regulated by CD40-TRAF6 signaling between myeloid and adaptive immune cells, and that this signaling can be efficiently leveraged for therapeutic purposes.
Project description:Trained immunity refers to epigenetic and metabolic changes in innate immune cells following exposure to inflammatory signals, leading to a heightened response to secondary stimuli. Although this innate immune memory contributes to host defense against infections, it can also have maladaptive consequences in a broad range of immune-driven conditions. During the past decade, we have gained an increasingly better understanding of the molecular regulation of trained immunity, but the role of adaptive immune cells in modulation of trained immunity remains largely unknown. Here, we show that T cell interactions contribute to the induction of trained immunity in monocytes and that this mediated by CD40-TRAF6 signaling. Specifically, we found that inhibiting CD40-TRAF6 signaling prevents the induction of functional, transcriptomic, metabolic and epigenetic changes associated with trained immunity. Apart from detailed in vitro studies, we inhibited CD40-TRAF6 signaling in vivo in myeloid cells in a murine heart transplantation model which resulted in prolonged allograft survival. When the animals were additionally treated with costimulatory blockade by CTLA4-Ig, we observed immunological tolerance to the graft. Combined, our study reveals that trained immunity induction is regulated by CD40-TRAF6 signaling between myeloid and adaptive immune cells, and that this signaling can be efficiently leveraged for therapeutic purposes.
Project description:Recent studies have demonstrated that both mouse and human alpha beta TCR(+)CD3(+)NK1.1(-)CD4(-)CD8- double-negative regulatory T (DN Treg) cells can suppress Ag-specific immune responses mediated by CD8+ and CD4+ T cells. To identify molecules involved in DN Treg cell function, we generated a panel of murine DN Treg clones, which specifically kill activated syngeneic CD8+ T cells. Through serial cultivation of DN Treg clones, mutant clones arose that lost regulatory capacity in vitro and in vivo. Although all allogeneic cardiac grafts in animals preinfused with tolerant CD4/CD8 negative 12 DN Treg clones survived over 100 days, allograft survival is unchanged following infusion of mutant clones (19.5 +/- 11.1 days) compared with untreated controls (22.8 +/- 10.5 days; p < 0.001). Global gene expression differences between functional DN Treg cells and nonfunctional mutants were compared. We found 1099 differentially expressed genes (q < 0.025%), suggesting increased cell proliferation and survival, immune regulation, and chemotaxis, together with decreased expression of genes for Ag presentation, apoptosis, and protein phosphatases involved in signal transduction. Expression of 33 overexpressed and 24 underexpressed genes were confirmed using quantitative real-time PCR. Protein expression of several genes, including Fc epsilon RI gamma subunit and CXCR5, which are >50-fold higher, was also confirmed using FACS. These findings shed light on the mechanisms by which DN Treg cells down-regulate immune responses and prolong cardiac allograft survival. Type 2 experiment where functional DN T-reg cells (CN4 or TN12) were cy-3 labeled and co-hybridized with non-functional mutant cell lines (CN4.8 or CN12.8). Used 100 ug total-RNA each channel and no amplifaction. A transcript identification design type characterizes the length and position of transcripts and allows identification of all forms of transcripts in the genome. Keywords: transcript_identification_design