ABSTRACT: 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:Monocyte differentiation into macrophages represents one of the cornerstone processes in innate host defense. In addition, immunological imprinting of either tolerance or trained immunity after an initial infection determines the functional fate of innate immune cells and the susceptibility of the host to secondary infections. Here we comprehensively characterize the epigenetic profiles of these functional states relative to healthy adult naM-CM-/ve monocytes. Inflammatory and metabolic pathways are strongly modulated in the derived macrophages, including decreased activation of inflammasome components. The cAMP-dependent signaling pathway is remodeled and adrenergic signaling was functionally implicated in trained innate immunity induction in vivo. Interestingly, M-oM-^AM-"-Glucan trains innate immune cells through extensive remodeling of distal regulatory region-bound histone acetylation, resulting in a sizeable exclusive epigenomic signature. Accordingly, genome-wide transcription factor footprint analysis reveals a specific transcription factor repertoire at trained cell-specific enhancers when recouped with epigenetic data, forming a rich hypothesis generator to manipulate innate immunity. Monocytes were pre-incubated either with cell culture medium (RPMI), M-NM-2-glucan (5M-BM-5g/mL) or with LPS (100ng/mL), for 24 hours in a total volume of 10 mL. After a wash-out, cells were cultured in RPMI supplemented with 10% human pool serum. Monocytes were collected at different time points (0 h and 6 d after treatment) and counted before further treatment for chromatin immunoprecipitation, RNA or DNaseI treatment. Different donor Buffycoats (BC) were used as independent replicates. Replicates were generated for all the profiles including ChIPseq,RNAseq and DNaseIseq.
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:Monocyte differentiation into macrophages represents one of the cornerstone processes in innate host defense. In addition, immunological imprinting of either tolerance or trained immunity after an initial infection determines the functional fate of innate immune cells and the susceptibility of the host to secondary infections. Here we comprehensively characterize the epigenetic profiles of these functional states relative to healthy adult naïve monocytes. Inflammatory and metabolic pathways are strongly modulated in the derived macrophages, including decreased activation of inflammasome components. The cAMP-dependent signaling pathway is remodeled and adrenergic signaling was functionally implicated in trained innate immunity induction in vivo. Interestingly, -Glucan trains innate immune cells through extensive remodeling of distal regulatory region-bound histone acetylation, resulting in a sizeable exclusive epigenomic signature. Accordingly, genome-wide transcription factor footprint analysis reveals a specific transcription factor repertoire at trained cell-specific enhancers when recouped with epigenetic data, forming a rich hypothesis generator to manipulate innate immunity.
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: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: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:Trained immunity is classically characterized by long-term epigenetic reprogramming of innate immune cells to combat infectious diseases. Infection-induced organ injury is a common clinical severity phenotype of sepsis. However, whether the induction of trained immunity plays a role in protecting septic-organ injury remains largely unknown. Here, through establishing an in vivo β-glucan training and secondary LPS challenge-induced organ injury model in zebrafish larvae, we observe that induction of trained immunity could inhibit the pyroptosis of hepatocytes to alleviate septic-liver injury, with an elevated epigenetic modification of trimethylation at histone 3 lysine 4 (H3K4me3) that targets mitophagy activation. Moreover, we identify a novel C-type lectin domain receptor in zebrafish, named DrDectin-1, which is revealed as the orchestrator in gating H3K4me3 rewiring-mediated mitophagy activation and alleviating the pyroptosis-engaged septic-liver injury in vivo. Taken together, our results uncover a tissue-resident trained immunity in maintaining tissue homeostasis at a whole animal level, and offer a facile in vivo model to efficiently integrate trained immunity for immunotherapies.
Project description:Trained immunity is the heightened state of innate immune memory that enhances immune response resulting in nonspecific protection. Epigenetic changes and metabolic reprogramming are critical steps that regulate trained immunity. In this study, we reported the involvement of O6-methylguanine DNA methyltransferase (MGMT), a DNA repair enzyme of lesion induced by alkylating agents, in regulation the trained immunity induced by β-glucan (BG). Pharmacological inhibition or silencing of MGMT expression altered LPS stimulated pro-inflammatory cytokine productions in BG-trained bone marrow derived macrophages (BMMs). Targeted deletion of Mgmt in BMMs resulted in reduction of the trained responses both in vitro and in vivo models. The transcriptomic analysis revealed that the dampening trained immunity in MGMT KO BMMs is partially mediated by ATM/FXR/AMPK axis affecting the MAPK/mTOR/HIF1α pathways and the reduction in glycolysis function. Taken together, a failure to resolve a DNA damage may have consequences for innate immune memory.