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:We demonstrate that hydroxychloroquine inhibits trained immunity at the functional and epigenetic level and is accompanied by reduced expression of interferon-stimulated genes. Trained immunity comprises a functional adaptation induced by epigenetic reprogramming which facilitates the anti-viral innate immune response.
Project description:scRNAseq of monocytes from in vitro Trained immunity experiments stimulated by β-glucan (BG), uric acid (UA), muramyl dipeptide (MDP), oxidized low-density lipoprotein (oxLDL), or RPMI-Control, and respective samples restimulated with Lipopolysaccharide (LPS).
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.