Project description:Inflammatory diseases such as Aicardi-Goutières syndrome and severe systemic lupus erythematosus are generally lethal disorders that have been traced to defects in the exonuclease TREX1 (DNase III). Mice lacking TREX1 similarly die at an early age through comparable symptoms, including inflammatory myocarditis, through chronic activation of the stimulator of IFN genes (STING) pathway. In this study, we demonstrate that phagocytes rather than myocytes are predominantly responsible for causing inflammation, an outcome that could be alleviated following adoptive transfer of normal bone marrow into TREX1(-/-) mice. TREX1(-/-) macrophages did not exhibit significant augmented ability to produce proinflammatory cytokines compared with normal macrophages following exposure to STING-dependent activators, but rather appeared chronically stimulated by genomic DNA. These results shed molecular insight into inflammation and provide concepts for the design of new therapies.
Project description:Inflammatory diseases such as Aicardi-Goutieres Syndrome (AGS) and severe systemic lupus erythematosus (SLE) are generally lethal disorders that have been traced to defects in the exonuclease Trex1 (DNAseIII). Mice lacking Trex1 similarly die at an early age through comparable symptoms, including inflammatory myocarditis, through chronic activation of the STING (stimulator of interferon genes) pathway. Here we demonstrate that phagocytes rather than myocytes are predominantly responsible for causing inflammation, an outcome that could be alleviated following adoptive transfer of normal bone marrow into Trex1-/- mice. Trex1-/- macrophages did not exhibit significant augmented ability to produce pro-inflammatory cytokines compared to normal macrophages following exposure to STING-dependent activators, but rather appeared chronically stimulated by genomic DNA. These results shed molecular insight into inflammation and provide concepts for the design of new therapies. Total RNA obtained from wild type murine embryonic fibroblasts (WT MEFs), Trex1 deficient MEFs (TKO) or STING and Trex1 double deficient MEFs (STKO) transfected with or without double strand DNA 90 (ISD) and examined cytokine production by these cells.
Project description:Inflammatory diseases such as Aicardi-Goutieres Syndrome (AGS) and severe systemic lupus erythematosus (SLE) are generally lethal disorders that have been traced to defects in the exonuclease Trex1 (DNAseIII). Mice lacking Trex1 similarly die at an early age through comparable symptoms, including inflammatory myocarditis, through chronic activation of the STING (stimulator of interferon genes) pathway. Here we demonstrate that phagocytes rather than myocytes are predominantly responsible for causing inflammation, an outcome that could be alleviated following adoptive transfer of normal bone marrow into Trex1-/- mice. Trex1-/- macrophages did not exhibit significant augmented ability to produce pro-inflammatory cytokines compared to normal macrophages following exposure to STING-dependent activators, but rather appeared chronically stimulated by genomic DNA. These results shed molecular insight into inflammation and provide concepts for the design of new therapies. Total RNA obtained from wild type (WT), Trex1 deficient (TKO), STING deficient (SKO), or Trex1 and STING double deficient (STKO) mouse Heart
Project description:Inflammatory diseases such as Aicardi-Goutieres Syndrome (AGS) and severe systemic lupus erythematosus (SLE) are generally lethal disorders that have been traced to defects in the exonuclease Trex1 (DNAseIII). Mice lacking Trex1 similarly die at an early age through comparable symptoms, including inflammatory myocarditis, through chronic activation of the STING (stimulator of interferon genes) pathway. Here we demonstrate that phagocytes rather than myocytes are predominantly responsible for causing inflammation, an outcome that could be alleviated following adoptive transfer of normal bone marrow into Trex1-/- mice. Trex1-/- macrophages did not exhibit significant augmented ability to produce pro-inflammatory cytokines compared to normal macrophages following exposure to STING-dependent activators, but rather appeared chronically stimulated by genomic DNA. These results shed molecular insight into inflammation and provide concepts for the design of new therapies.
Project description:Inflammatory diseases such as Aicardi-Goutieres Syndrome (AGS) and severe systemic lupus erythematosus (SLE) are generally lethal disorders that have been traced to defects in the exonuclease Trex1 (DNAseIII). Mice lacking Trex1 similarly die at an early age through comparable symptoms, including inflammatory myocarditis, through chronic activation of the STING (stimulator of interferon genes) pathway. Here we demonstrate that phagocytes rather than myocytes are predominantly responsible for causing inflammation, an outcome that could be alleviated following adoptive transfer of normal bone marrow into Trex1-/- mice. Trex1-/- macrophages did not exhibit significant augmented ability to produce pro-inflammatory cytokines compared to normal macrophages following exposure to STING-dependent activators, but rather appeared chronically stimulated by genomic DNA. These results shed molecular insight into inflammation and provide concepts for the design of new therapies.
Project description:Inflammatory autoimmune diseases such as systemic lupus erythematosus (SLE) and polyarthritis are characterized by chronic cytokine overproduction, suggesting that the stimulation of host innate immune responses, speculatively by persistent infection or self nucleic acids, plays a role in the manifestation of these disorders. Mice lacking DNase II die during embryonic development through comparable inflammatory disease because phagocytosed DNA from apoptotic cells cannot be adequately digested and intracellular host DNA sensor pathways are engaged, resulting in the production of a variety of cytokines including type I IFN. The cellular sensor pathway(s) responsible for triggering DNA-mediated inflammation aggravated autoimmune disease remains to be determined. However, we report here that Stimulator of IFN Genes (STING) is responsible for inflammation-related embryonic death in DNase II defective mice initiated by self DNA. DNase II-dependent embryonic lethality was rescued by loss of STING function, and polyarthritis completely prevented because cytosolic DNA failed to robustly trigger cytokine production through STING-controlled signaling pathways. Our data provides significant molecular insight into the causes of DNA-mediated inflammatory disorders and affords a target that could plausibly be therapeutically controlled to help prevent such diseases.