Project description:Inflammasomes are intracellular innate immune sensors that respond to pathogen and damage-associated signals with the proteolytic cleavage of caspase-1, resulting in IL-1_ and IL-18 secretion and macrophage pyroptosis. The discovery that heterozygous gain-of-function mutations in NLRP3 lead to oversecretion of IL-1_ and cause the autoinflammatory disease spectrum Cryopyrin Associated Periodic Syndrome (CAPS), led to the successful use of IL-1 blocking therapies1. We found that a de novo missense mutation in the regulatory domain of the NLRC4 (IPAF, CARD12) inflammasome causes early-onset recurrent fever flares and Macrophage Activation Syndrome (MAS). Functional analyses demonstrated spontaneous production of the inflammasome-dependent cytokines IL-1² and IL-18 exceeding levels in CAPS patients. The NLRC4 mutation led to constitutive caspase-1 cleavage in transduced cells and enhanced spontaneous production of IL-18 by both patient and NLRC4 mutant macrophages. Thus, we describe a novel monoallelic inflammasome defect that expands the autoinflammatory paradigm to include MAS and suggests novel targets for therapy.
2014-09-08 | GSE57253 | GEO
Project description:Gene Mutation Causes a Syndrome of Combined Immunodeficiency
Project description:Inflammasomes are intracellular innate immune sensors that respond to pathogen and damage-associated signals with the proteolytic cleavage of caspase-1, resulting in IL-1_ and IL-18 secretion and macrophage pyroptosis. The discovery that heterozygous gain-of-function mutations in NLRP3 lead to oversecretion of IL-1_ and cause the autoinflammatory disease spectrum Cryopyrin Associated Periodic Syndrome (CAPS), led to the successful use of IL-1 blocking therapies1. We found that a de novo missense mutation in the regulatory domain of the NLRC4 (IPAF, CARD12) inflammasome causes early-onset recurrent fever flares and Macrophage Activation Syndrome (MAS). Functional analyses demonstrated spontaneous production of the inflammasome-dependent cytokines IL-1² and IL-18 exceeding levels in CAPS patients. The NLRC4 mutation led to constitutive caspase-1 cleavage in transduced cells and enhanced spontaneous production of IL-18 by both patient and NLRC4 mutant macrophages. Thus, we describe a novel monoallelic inflammasome defect that expands the autoinflammatory paradigm to include MAS and suggests novel targets for therapy. Whole blood RNA-seq from seven timepoints of one patient with NLRC4-MAS as compared to five healthy pediatric controls, 7 NOMID patients with active disease prior to anakinra treatment and the same 7 NOMID patients with inactive disease after anakinra treatment. Please note that seven time points are chronologic time point. They are ordinal, in that "1" was drawn before "2", but the distance in time between points is not constant. Thus, time points 4 through 7 correspond to samples drawn while the patient was well AND on treatment. However there may be differences between 4 and 7 pertaining to the length of treatment, and for that reason any of these samples were not considered replicates.
Project description:Hematopoietic stem and progenitor cells derived from a zebrafish model of Noonan syndrome, carrying a patient-associated Shp2-D61G mutation, display an expansion of monocyte/macrophage progenitors with an inflammatory gene expression signature.
Project description:While certain human genetic variants are conspicuously loss-of-function, decoding the functional impact of many variants is challenging. Previously, we described a leukemia predisposition syndrome (GATA2-deficiency) patient with a germline GATA2 variant that inserts nine amino acids between the two zinc fingers (9aa-Ins). Here, we conducted mechanistic analyses using genomic technologies in Gata2 enhancer-mutant hematopoietic progenitor cells to reveal how the insertion impacts GATA2 function genome-wide. Despite being nuclear-localized, 9aa-Ins was severely defective, with activation more impaired than repression. Variation of the inter-zinc finger spacer length revealed that repression tolerated insertions that were detrimental to activation. GATA2 deficiency generated a hematopoiesis-disrupting signaling network in progenitor cells with reduced Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) signaling and elevated Interleukin-6 (IL-6) signaling. As insufficient GM-CSF signaling causes pulmonary alveolar proteinosis and excessive IL-6 signaling causes bone marrow failure, hallmark phenotypes of GATA2-deficiency patients, these results establish molecular mechanisms underlying GATA2-linked pathologies.
Project description:While certain human genetic variants are conspicuously loss-of-function, decoding the functional impact of many variants is challenging. Previously, we described a leukemia predisposition syndrome (GATA2-deficiency) patient with a germline GATA2 variant that inserts nine amino acids between the two zinc fingers (9aa-Ins). Here, we conducted mechanistic analyses using genomic technologies in Gata2 enhancer-mutant hematopoietic progenitor cells to reveal how the insertion impacts GATA2 function genome-wide. Despite being nuclear-localized, 9aa-Ins was severely defective, with activation more impaired than repression. Variation of the inter-zinc finger spacer length revealed that repression tolerated insertions that were detrimental to activation. GATA2 deficiency generated a hematopoiesis-disrupting signaling network in progenitor cells with reduced Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) signaling and elevated Interleukin-6 (IL-6) signaling. As insufficient GM-CSF signaling causes pulmonary alveolar proteinosis and excessive IL-6 signaling causes bone marrow failure, hallmark phenotypes of GATA2-deficiency patients, these results establish molecular mechanisms underlying GATA2-linked pathologies.