Project description:We have successfully created induced pluripotent stem cells (iPSC) from patients carrying a heterozygous mutation in the gene encoding STING. The gain-of-function mutation leads to constitutive activation of STING which leads to the development of the disease STING-associated vasculopathy with onset in infancy (SAVI). The iPSC lines derived from the SAVI patitents are shown to be morphologically and phenotypically normal and have the potential to self renew and differentiate into the three germ layers. These iPSC provide a powerful tools to investigate the role of STING in the regulation of immune responses and vascular renegeration.
Project description:Apolipoprotein L1 (APOL1) risk variants G1 and G2 are known to result in risk for kidney disease in patients of African ancestry. APOL1-associated nephropathy typically occurs in association with certain environmental factors or systemic diseases. As such, there has been increasing evidence of the role of interferon (IFN) pathways in the pathogenesis of APOL1-associated collapsing glomerulopathy in patients with human immunodeficiency virus (HIV) infection and systemic lupus erythematosus, 2 conditions that are associated with high IFN levels. Collapsing glomerulopathy has also been described in patients receiving exogenous IFN therapy administered for various medical conditions. We describe a patient with a genetic condition that results in an increased IFN state, stimulator of IFN genes (STING)-associated vasculopathy with onset in infancy (SAVI), who developed collapsing glomerulopathy during a flare of his disease. The patient was found to have APOL1 G1 and G2 risk variants. This case supports the role of IFN in inducing APOL1-associated collapsing glomerulopathy.
Project description:Gain-of-function variants in the stimulator of interferon response cGAMP interactor 1 (STING1) gene cause STING-Associated Vasculopathy with onset in Infancy (SAVI). Previously, only heterozygous and mostly de novo STING1 variants have been reported to cause SAVI. Interestingly, one variant that only leads to SAVI when homozygous, namely c.841C>T p.(Arg281Trp), has recently been described. However, there are no entries in public databases regarding an autosomal recessive pattern of inheritance. Here, we report four additional unrelated SAVI patients carrying c.841C>T in homozygous state. All patients had interstitial lung disease and displayed typical interferon activation patterns. Only one child displayed cutaneous vasculitis, while three other patients presented with a relatively mild SAVI phenotype. Steroid and baricitinib treatment had a mitigating effect on the disease phenotype in two cases, but failed to halt disease progression. Heterozygous c.841C>T carriers in our analysis were healthy and showed normal interferon activation. Literature review identified eight additional cases with autosomal recessive SAVI caused by c.841C>T homozygosity. In summary, we present four novel and eight historic cases of autosomal recessive SAVI. We provide comprehensive clinical data and show treatment regimens and clinical responses. To date, SAVI has been listed as an exclusively autosomal dominant inherited trait in relevant databases. With this report, we aim to raise awareness for autosomal recessive inheritance in this rare, severe disease which may aid in early diagnosis and development of optimized treatment strategies.
Project description:STING-associated vasculopathy of infantile-onset (SAVI) is one of the newly identified types of interferonopathies. SAVI is caused by heterozygous gain-of-function mutations in the STING1. We herein report for the first time a homozygous variant in the STING1 gene in two siblings that resulted in constitutive activation of STING gene and the SAVI phenotype. Exome sequencing revealed a novel homozygous NM_198282.3: c.841C>T; p.(Arg281Trp) variant in exon 7 of the STING1 gene. The variant segregated in the family to be homozygous in all affected and either heterozygous or wild type in all healthy. Computational structural analysis of the mutants revealed changes in the STING protein structure/function. Elevated serum beta-interferon levels were observed in the patients compared to the control family members. Treatment with Janus kinase inhibitor (JAK-I) Ruxolitinib suppressed the inflammatory process, decreased beta-interferon levels, and stopped the progression of the disease.
Project description:Stimulator of interferon genes (STING1) is a key intermediary in activating the type I IFN response. STING-associated vasculopathy with onset in infancy (SAVI) is a very rare autoinflammatory disease that is caused by heterozygous gain-of-function mutations in STING1. SAVI typically manifests as neonatal-onset systemic inflammation, interstitial lung disease (ILD), and severe cutaneous vasculopathy located in acral regions, including fingers, toes, ears, and nose. Severity of ILD and recurrent pulmonary infections are crucial for the prognosis. Therapeutic options for SAVI are quite limited, and JAK inhibitors are considered to be a promising treatment according to several recent case reports. We report on a familial case series of SAVI with the R281Q mutation in the STING1 gene with predominant ILD manifestations, absence of cutaneous lesions, and poor response to ruxolitinib. Moreover, we reviewed all the case reports of SAVI in English published in the PubMed database. The atypical phenotype of the current cases adds to the growing list of inflammatory syndromes associated with SAVI. The literature analysis suggests that the severity and natural courses of the disease seem to be independent of the mutation type. Although JAK inhibitors may be a promising treatment, the therapeutic effect for different phenotypes and disease statuses of SAVI warrants further investigation.
Project description:Gain-of-function mutations in STING cause STING-associated vasculopathy with onset in infancy (SAVI) characterized by early-onset systemic inflammation, skin vasculopathy, and interstitial lung disease. Here, we report and characterize a novel STING variant (F269S) identified in a SAVI patient. Single-cell transcriptomics of patient bone marrow revealed spontaneous activation of interferon (IFN) and inflammatory pathways across cell types and a striking prevalence of circulating naïve T cells was observed. Inducible STING F269S expression conferred enhanced signaling through ligand-independent translocation of the protein to the Golgi, protecting cells from viral infections but preventing their efficient immune priming. Additionally, endothelial cell activation was promoted and further exacerbated by cytokine secretion by SAVI immune cells, resulting in inflammation and endothelial damage. Our findings identify STING F269S mutation as a novel pathogenic variant causing SAVI, highlight the importance of the crosstalk between endothelial and immune cells in the context of lung disease, and contribute to a better understanding of how aberrant STING activation can cause pathology.
Project description:BackgroundGain-of-function mutations in STING1 (also known as TMEM173) which result in constitutive activation of STING, have been reported to cause STING-associated vasculopathy with onset in infancy (SAVI). Although a wider spectrum of associated manifestations and perturbations in disease onset have been observed since its description, the genotype-phenotype correlations are not definite, and there is no established treatment protocol for SAVI.Case presentationHerein, we report a kindred, heterozygous STING mutation (p.V155M) in which the 2-year-old proband suffered from severe interstitial lung disease (ILD) while her father was initially misdiagnosed with connective tissue disease associated with ILD at an adult age. Baricitinib was initiated after the diagnosis of SAVI in the proband combined with steroids, and during the 14-month follow-up, the respiratory symptoms were improved. However, as the improvement of laboratory indicators was limited, especially in autoimmune indices, and the lung CT images remained unaltered, it seems that JAK1/2 inhibition was unsatisfactory in completely controlling the inflammation of the disease in our study.ConclusionsBaricitinib was shown to elicit some effect on the ILD but failed to control the inflammation of the disease completely. Further exploration of JAK inhibitors or other therapeutic strategies are needed to more optimally treat this inflammatory disease.
Project description:Gain-of-function mutations in STING1 cause the monogenic interferonopathy, SAVI, which presents with early-onset systemic inflammation, cold-induced vasculopathy and/or interstitial lung disease. We identified 5 patients (3 kindreds) with predominantly peripheral vascular disease who harbor 3 novel STING1 variants, p.H72N, p.F153V, and p.G158A. The latter two were predicted by a previous cryo-EM structure model to cause STING autoactivation. The p.H72N variant in exon 3, however, is the first SAVI-causing variant in the transmembrane linker region. Mutations of p.H72 into either charged residues or hydrophobic residues all led to dramatic loss of cGAMP response, while amino acid changes to residues with polar side chains were able to maintain the wild type status. Structural modeling of these novel mutations suggests a reconciled model of STING activation, which indicates that STING dimers can oligomerize in both open and closed states which would obliviate a high-energy 180° rotation of the ligand-binding head for STING activation, thus refining existing models of STING activation. Quantitative comparison showed that an overall lower autoactivating potential of the disease-causing mutations was associated with less severe lung disease, more severe peripheral vascular disease and the absence of a robust interferon signature in whole blood. Our findings are important in understanding genotype-phenotype correlation, designing targeted STING inhibitors and in dissecting differentially activated pathways downstream of different STING mutations.
Project description:Gain-of-function mutations in STING cause STING-associated vasculopathy with onset in infancy (SAVI) characterized by early-onset systemic inflammation, skin vasculopathy, and interstitial lung disease. Here, we report and characterize a novel STING variant (F269S) identified in a SAVI patient. single-cell transcriptomics of patient bone marrow revealed spontaneous activation of interferon (IFN) and inflammatory pathways across cell types and a striking prevalence of circulating naïve T cells was observed. Inducible STING F269S expression conferred enhanced signaling through ligand-independent translocation of the protein to the Golgi, protecting cells from viral infections but preventing their efficient immune priming. Additionally, endothelial cell activation was promoted and further exacerbated by cytokine secretion by SAVI immune cells, resulting in inflammation and endothelial damage. Our findings identify STING F269S mutation as a novel pathogenic variant causing SAVI, highlight the importance of the crosstalk between endothelial and immune cells in the context of lung disease and contribute to a better understanding of how aberrant STING activation can cause pathology.