Project description:Lymphocytic myocarditis is characterized by infiltration of lymphocytes and macrophages. Current treatment for lymphocytic myocarditis is limited to corticosteroids and a proportion of patients progress to require heart transplantation or durable mechanical circulatory support within a year. Increasing attention is directed toward targeting pro-inflammatory mediators in myocarditis. One promising candidate is IL-1. Here, we investigated a patient with underlying autoimmune disease and biopsy confirmed lymphocytic myocarditis who was initially treated with corticosteroids and experienced clinical deterioration requiring temporary mechanical circulatory support. Rilonacept was consequently administered as a salvage therapy. Pathologically, rilonacept reduced inflammation and fibrosis. We performed spatial transcriptomics (ST) on formalin-fixed paraffin-embedded endomyocardial biopsy samples to further investigate how the cardiac immune landscape is modulated by rilonacept.
Project description:Psoriasis vulgaris and other chronic inflammatory diseases improve markedly with therapeutic blockade of IL-23 signaling in T cells, but the genetic mechanisms of response remain poorly understood. We single-cell transcriptomically profiled CD45+ immune cells isolated from lesional psoriatic skin before and after IL-23 blockade. In clinically responsive patients, a psoriatic transcriptional signature in skin-resident memory T cells was sharply attenuated. In contrast, poorly responsive patients were distinguished by enduring T17 cell activation, a mechanism distinct from alternative cytokine signaling or downstream resistance. Spatial transcriptomic analysis suggests that successful IL-23 blockade requires dampening of > 90% of IL-17-induced signaling in lymphocyte-adjacent keratinocytes, an unexpectedly high threshold. We also detected a subset of persistent, disease-specific T17 abnormalities in responsive patients, revealing an irreversible cell identity that may necessitate ongoing IL-23 inhibition. Collectively, our data establishes a patient-level paradigm for dissecting response to immunomodulatory treatments.
Project description:Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have revolutionized cancer management but are associated with devastating immune-related adverse events (irAEs) including myocarditis. The main risk factor for ICI myocarditis is the use of combination PD-1 and CTLA4 inhibition. ICI-myocarditis is often fulminant and is pathophysiologically characterized by myocardial infiltration of T lymphocytes and macrophages. While much has been learned regarding the role of T-cells in ICI-myocarditis, little is understood regarding the identity, transcriptional diversity, and functions of infiltrating macrophages. We employed an established murine ICI myocarditis model (Ctla4+/-Pdcd1-/- mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, and molecular imaging. We observed marked increases in CCR2+ monocyte-derived macrophages and CD8+ T-cells in this model. The macrophage compartment was heterogeneous and displayed marked enrichment in an inflammatory CCR2+ subpopulation expressing Cxcl9, Cxcl10, Gbp2b, and Fcgr4 that originated from CCR2+ monocytes. Importantly, a similar macrophage population expressing CXCL9, CXCL10, and CD16α (human homologue of mouse FcgR4) were found selectively in patients with ICI myocarditis compared to other forms of heart failure and myocarditis. In silico prediction of cell-cell communication suggested interactions between T-cells and Cxcl9+Cxcl10+ macrophages via IFN-γ and CXCR3 signaling pathways. Depleting CD8+T-cells and blockade of IFN-γ signaling blunted the emergence of Cxcl9+Cxcl10+ macrophages in the heart and attenuated myocarditis suggesting that this interaction was necessary for disease pathogenesis. Collectively, these data demonstrate that ICI-myocarditis is associated with the emergence of a specific population of inflammatory macrophages and suggest the possibility that IFN-γ blockade may serve as an effective treatment for this devastating condition.
Project description:The aim of this study was to compare the signaling cascades initiated by the two closely related cytokines IL-2 and IL-15. Considering the relevance of protein tyrosine phosphorylation in signal transduction, in order to quantify changes in protein phosphorylation in response to IL-2 and IL-15, we combined triple SILAClabeling of leukemic T-cells with phosphotyrosine (pY)-specific antibody-based protein enrichment followed by mass spectrometry (MS) analysis. Following the strategy described above, we managed to decipher in detail the complex signaling networks triggered by IL-2 and IL-15. Interestingly, a large number of components of the three main signaling pathways known to be initiated in response to the interleukins (JAK/STAT; RAS/MAPK; PI3K/AKT) were identified.
Project description:Immune checkpoint inhibitors (ICIs) are effective against many cancers but can also cause immune-related adverse events. Although rare, ICI-mediated myocarditis has a high fatality rate of up to 40% and is also associated with heart failure and life-threatening arrhythmias. We characterized a population of CXCL9+CXCL10+ macrophages and CXCR3hi CD8+ T-cells in the hearts of mice with myocarditis and elucidated chemokine crosstalk between the CXCR3hi CD8+ effector T-cells and the CXCL9+CXCL10+ macrophages in the heart. Depletion of macrophages or blockade of CXCR3 both resulted in significantly decreased immune cell infiltration in the hearts of mice. Similarly, CXCR3 blockade decreased immune cell infiltration into the heart,, thus posing CXCR3 and its ligands as an attractive therapeutic target. Additionally, an in vitro transwell assay showed that selective blockade of CXCR3 and its ligand CXCL10 significantly decreased CD8+ T-cell migration towards macrophages, implicating this interaction in T-cell cardiotropism towards cardiac macrophages. These findings were compared with cardiac biopsies from patients with ICI myocarditis that also demonstrated infiltrating CXCR3+ lymphocytes and CXCL9+/CXCL10+ macrophages. In both mouse cardiac immune cells and patient peripheral blood immune cells, T-cell receptor (TCR)-sequencing revealed expanded TCRs that correlated with CXCR3hi CD8+ T-cells. The identification of a CXCR3-specific T-cell and macrophage interaction as important in the pathogenesis of ICI myocarditis offers a new potential target for a chemokine/chemokine receptor inhibition-focused form of therapy in this disease.
Project description:Inflammatory factors that activate NFkB play an important role in the pathogenesis of chronic lymphocytic leukemia (CLL) but are not addressed specifically by current therapies. Interleukin-1 (IL-1) is a master-regulator of inflammation that is inhibited safely in humans by the IL-1 receptor antagonist anakinra. Anakinra (K) was found to inhibit NFkB activity in CLL cells in an IL-1 receptor independent manner and had properties of an intracellular anti-oxidant in vitro.
Project description:The efficacy of costimulation blockade (CTLA4Ig/belatacept) in transplantation is reduced by an increased incidence of T cell-mediated rejection, which also persists after induction therapy with anti-thymocyte globulin (ATG). Herein, we investigate why ATG fails to prevent costimulation blockade-resistant rejection and how this barrier can be overcome. ATG did not prevent graft rejection in a murine heart transplant model of CTLA4Ig therapy and induced a pro-inflammatory cytokine environment. While ATG improved the balance between Tregs and effector T cells in the peripheral compartment, it had no such effect within cardiac allografts, which showed signs of inflammation. Neutralizing IL-6 alleviated inflammation, increased intragraft Treg frequencies long-term, and enhanced intragraft IL-10 and Th2 cytokine expression. IL-6 blockade together with ATG led to long-term, rejection-free heart graft survival under CTLA4Ig therapy. Combining ATG with IL-6 blockade prevents costimulation blockade-resistant rejection, thereby eliminating a major impediment to clinical use of costimulation blockers in transplantation.
Project description:The efficacy of costimulation blockade (CTLA4Ig/belatacept) in transplantation is reduced by an increased incidence of T cell-mediated rejection, which also persists after induction therapy with anti-thymocyte globulin (ATG). Herein, we investigate why ATG fails to prevent costimulation blockade-resistant rejection and how this barrier can be overcome. ATG did not prevent graft rejection in a murine heart transplant model of CTLA4Ig therapy and induced a pro-inflammatory cytokine environment. While ATG improved the balance between Tregs and effector T cells in the peripheral compartment, it had no such effect within cardiac allografts, which showed signs of inflammation. Neutralizing IL-6 alleviated inflammation, increased intragraft Treg frequencies long-term, and enhanced intragraft IL-10 and Th2 cytokine expression. IL-6 blockade together with ATG led to long-term, rejection-free heart graft survival under CTLA4Ig therapy. Combining ATG with IL-6 blockade prevents costimulation blockade-resistant rejection, thereby eliminating a major impediment to clinical use of costimulation blockers in transplantation.
Project description:The aim of this study was to compare the signaling cascades initiated by the two closely related cytokines IL-2 and IL-15. Considering the relevance of protein tyrosine phosphorylation in signal transduction, in order to quantify changes in protein phosphorylation in response to IL-2 and IL-15, we combined triple SILAClabeling of leukemic T-cells with phosphotyrosine (pY)-specific antibody-based protein enrichment followed by mass spectrometry (MS) analysis. Following the strategy described above, we managed to decipher in detail the complex signaling networks triggered by IL-2 and IL-15. Interestingly, a large number of components of the three main signaling pathways known to be initiated in response to the interleukins (JAK/STAT; RAS/MAPK; PI3K/AKT) were identified.