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Biology subjects

Jenne, D. E.

Publications and source records attributed to Jenne, D. E..

5 recordsLinked to original sources

Unconventional presentation of an immunodominant HLA-DR15-restricted nephritogenic proteinase 3 epitope implicated in vasculitis

Proteinase 3 (PR3) anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is associated with HLA-DR15, implicating HLA-DR15-restricted CD4 T cell autoimmunity in the disease. However, the PR3 epitopes presented by HLA-DR15 and the autoreactive CD4 T cell responses they elicit are undefined. Using humanized hPR3.DR15+ mice, we identified PR3216-231 as an immunodominant human PR3-derived CD4 T cell epitope presented by HLA-DR15. Immunopeptidomic profiling confirmed the natural processing and HLA-DR15-restricted presentation of PR3216-231. Structural analyses of HLA-DR15-PR3216-231 complexes revealed an unconventional mode of HLA class II antigen presentation, in which a 10 amino acid peptide core occupies the 9 amino acid binding groove, causing a central kink in the bound peptide. PR3216-231-specific CD4 T cells from both hPR3.DR15+ mice and patients with PR3-ANCA-associated vasculitis exhibited convergent T cell receptor features, and patients with active vasculitis displayed a clonally expanded, PR3216-231-specific CD4 TCR repertoire. Immunization of hPR3.DR15 mice with PR3216-231 induced cell-mediated glomerulonephritis characterized by increased renal infiltration of CD4 T cells and macrophages together with segmental glomerular necrosis. These findings identify a nephritogenic PR3-derived CD4 T cell epitope presented by HLA-DR15 in ANCA-associated vasculitis and define a new extended core binding pattern, broadening our understanding of HLA class II peptide presentation.

immunology↗

Monocyte-derived macrophages aggravate pulmonary vasculitis via cGAS/STING/IFN-mediated nucleic acid sensing

Autoimmune vasculitis is a group of life-threatening diseases, whose underlying pathogenic mechanisms are incompletely understood, hampering development of targeted therapies. Here, we demonstrate that patients suffering from anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) showed increased activity of the DNA sensor cGAS and enhanced IFN-I signature. To identify potential therapeutic targets, we developed a mouse model for pulmonary AAV that mimics severe disease in patients. Immunogenic DNA accumulated during disease onset, triggering cGAS/STING/IRF3-dependent IFN-I release that promoted endothelial damage, pulmonary hemorrhages, and lung dysfunction. Macrophage subsets played dichotomic roles in disease. While recruited monocyte-derived macrophages were major disease drivers by producing most IFN-{beta}, resident alveolar macrophages contributed to tissue homeostasis by clearing red blood cells and limiting infiltration of IFN-{beta}-producing macrophages. Moreover, pharmacological inhibition of STING, IFNAR-I or its downstream JAK/STAT signaling reduced disease severity and accelerated recovery. Our study unveils the importance of STING/IFN-I axis in promoting pulmonary AAV progression and identifies cellular and molecular targets to ameliorate disease outcome. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/493983v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@521964org.highwire.dtl.DTLVardef@13506org.highwire.dtl.DTLVardef@1403dbeorg.highwire.dtl.DTLVardef@958cc4_HPS_FORMAT_FIGEXP M_FIG C_FIG SummaryKessler et al. identify aberrant DNA recognition by cGAS/STING axis and IFN-I production by inflammatory macrophages as a major driver of severe ANCA-associated vasculitis (AAV). Pharmacological interventions blocking this pathway ameliorate disease and accelerate recovery, identifying potential targets for therapeutic intervention in patients.

immunology↗

Tumor-secreted versican co-opts myeloid IKKβ during metastasis

The mechanisms tumor cells use to hijack the immune system are largely uncharted. Here we used bioluminescent nuclear factor (NF)-{kappa}B reporter mice and macrophages to discover that metastatic tumors trigger NF-{kappa}B activation in host macrophages, dependent on mutant KRAS signaling and delivered via secretory versican. Versican activates NF-{kappa}B in tumor-associated macrophages via inhibitor of NF-{kappa}B kinase (IKK) {beta}, resulting in release of interleukin (IL)-1{beta} into the tumor microenvironment. Versican silencing in cancer cells or conditional IKK{beta} deletion in macrophages prevents myeloid NF-{kappa}B activation and metastasis. Versican is overexpressed and/or mutated in human cancers and metastatic effusions with KRAS mutations, predicts poor survival, can aid in the development of diagnostic platforms for pleural metastasis, and is druggable via toll-like receptor (TLR) 1/2 inhibition. The data indicate a cardinal role for tumor-derived versican in establishing cross-talk with macrophage IKK{beta} during metastasis and may foster the development of new therapies and diagnostic tools.

cancer biology↗

Mutation Effects on Remote Epitopes of An Autoantigen Decoded with Simulated B-Factors

Proteinase 3 (PR3) is a neutrophil serine protease targeted by anti-neutrophil cytoplasmic antibodies (ANCAs) in the autoimmune disease granulomatosis with polyangiitis (GPA)1-5. PR3 mutants were developed to investigate how PR3 interacts with the ANCAs and whether the interactions can be intervened by therapeutics. One mutant with a Ser195Ala mutation (iPR3-Val103) recognized as many ANCAs as wild-type PR3 (PR3-Val103)6-9, indicating that PR3-Val103 and iPR3-Val103 have equivalent ANCA-binding capabilities. A triple mutant of the latter (iHm5-Val103) bound a monoclonal antibody (moANCA518) from a patient with GPA on an epitope remote from the mutation sites. Unexpectedly, the corresponding epitope of iPR3-Val103 was inaccessible to moANCA518 under the same experimental conditions10,11. These observations demonstrate that a latent epitope of PR3 can be activated surprisingly by remote mutations in PR311. Here we report a comparative analysis of simulated B-factors (i.e., measurements of local mobility) of PR3-Val103, iPR3-Val103, and iHm5-Val103, demonstrating that the binding of moANCA518 to iHm5-Val103 is enabled by an increase in main-chain flexibility in the latent epitope caused by the remote muta-tions in iHm5-Val103. This epitope activation--achieved in vitro by remote mutations as we demonstrated or in vivo conceivably by remote protein>>protein interactions12 or remote po-lymorphisms--may be a fundamental feature of antibody-mediated autoimmune diseases. Rigidifying B-cell epitopes on an autoantigen with therapeutics designed using the B-factor analysis disclosed here may lead to effective treatments for these autoimmune diseases by making the autoantigen inaccessible to existing autoantibodies. This analysis may also be used to predict and characterize epitopes and remote mutation effects.

immunology↗

Preferential Binding of Anti-Neutrophil Cytoplasmic Antibodies to an Unexpected Epitope of a Chimeric Proteinase 3 Mutant

ObjectiveProteinase 3 (PR3) is the major antigen for anti-neutrophil cytoplasmic antibodies (ANCAs) in the systemic autoimmune vasculitis, granulomatosis with polyangiitis (GPA). PR3 anti-neutrophil cytoplasmic antibodies (PR3-ANCAs) recognize different epitopes on PR3. We aimed to study the effect of mutations on PR3 antigenicity. MethodsThe recombinant PR3 variants, iPR3 which is clinically used to detect PR3-ANCAs and iHm5 which contains three point mutations in Epitope 1 and 5 generated for epitope mapping studies, immunoassays and serum samples from patients enrolled in ANCA-associated vasculitis (AAV) clinical trials were used to screen the differential PR3-ANCA binding. Selective binding was determined by inhibition experiments. ResultsRather than a reduced binding of PR3-ANCAs to iHm5, we found substantially increased binding of the majority of PR3-ANCAs to iHm5 compared with iPR3. A monoclonal ANCA (moANCA518) from a patient with GPA was found to selectively bind to iHm5 within the mutation-free Epitope 3 and distant from the point mutations of iHm5 contained in Epitope 1 and 5. Binding of iPR3 to monoclonal antibody MCPR3-2 also induced recognition by moANCA518. ConclusionThe preferential binding of PR3-ANCAs from patients like the selective binding of moANCA518 to iHm5 is conferred by increased antigenicity of Epitope 3 on iHm5. This can also be induced on iPR3 when it is captured by monoclonal antibody MCPR-2. This previously unrecognized characteristic of PR3-ANCA interactions with its target antigen has implications for studying antibody-mediated autoimmune diseases, understanding of variable performance characteristics of immunoassays and design of potential novel treatment approaches.

immunology↗