bioRxiv (Cold Spring Harbor Laboratory), Mar 16, 2024
Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit an... more Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1/PD-L1, CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here, we leveraged genetic mouse models, single cell sequencing, and cell depletion studies to demonstrate that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2 + macrophages and subsequent recruitment of effector memory CD8 T-cells. We identify a positive feedback loop between CCR2 + macrophages and CD8 T-cells driven by IL12b, TNF, and IFN-γ signaling that promotes myocardial inflammation and show that prior exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates LV remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.
bioRxiv (Cold Spring Harbor Laboratory), Dec 24, 2023
Inflammation contributes to the pathogenesis of cardiac disease and represents a viable therapeut... more Inflammation contributes to the pathogenesis of cardiac disease and represents a viable therapeutic target for heart failure. Cardiac injury elicits recruitment of neutrophils, monocytes, and T-cells. Monocytes and their progeny represent are highly abundant, display incredible functional diversity, and are key determinants of myocardial inflammation. Much remains to be learned regarding mechanisms and signaling events that instruct monocyte fate decisions. We devised a genetic lineage tracing strategy using Ccr2 crERT2 Rosa2 LSL-tdTomato mice in combination with single cell RNA-sequencing to map the fate and differentiation trajectories of monocytes that infiltrate the heart after reperfused myocardial infarction (MI). We observe that monocyte recruitment is restricted to the first 5 days following MI. Infiltrating monocytes give rise to transcriptionally distinct and spatially restricted macrophage and dendritic cell-like subsets, dynamically shift over time, and chronically persist within the myocardium. Pseudotime analysis predicted two differentiation trajectories of monocyte-derived macrophages that are initially partitioned into the border and infarct zones, respectively. Among these trajectories, we show that macrophages expressing a type I IFN responsive signature are an intermediate population localized within the border zone and promote myocardial protection. Collectively, these data uncover new complexities of monocyte differentiation in the infarcted heart and suggest that modulating monocyte fate decisions may have clinical implications.
HIGHLIGHTS SARS-CoV-2 directly infects cardiomyocytes in patients with COVID-19 myocarditis and d... more HIGHLIGHTS SARS-CoV-2 directly infects cardiomyocytes in patients with COVID-19 myocarditis and does not infect cardiac macrophages, fibroblasts, or endothelial cells. COVID-19 myocarditis is characterized by a myeloid-rich inflammatory infiltrate. SARS-CoV-2 infects cardiomyocytes through an ACE2 and endosomal cysteine protease dependent pathway. Infection of hPSC-derived cardiomyocytes and engineered heart tissues show that cytokine production, sarcomere disassembly, and cell death were a direct consequence of cardiomyocyte infection. SARS-CoV-2 reduces cardiomyocyte contractility through sarcomere breakdown and cardiomyocyte cell death.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
SARS-CoV-2 triggers a complex systemic immune response in circulating blood mononuclear cells. Th... more SARS-CoV-2 triggers a complex systemic immune response in circulating blood mononuclear cells. The relationship between immune cell activation of the peripheral compartment and survival in critical COVID-19 remains to be established. Here we use single-cell RNA sequencing and Cellular Indexing of Transcriptomes and Epitomes by sequence mapping to elucidate cell type specific transcriptional signatures that associate with and predict survival in critical COVID-19. Patients who survive infection display activation of antibody processing, early activation response, and cell cycle regulation pathways most prominent within B-, T-, and NK-cell subsets. We further leverage cell specific differential gene expression and machine learning to predict mortality using single cell transcriptomes. We identify interferon signaling and antigen presentation pathways within cDC2 cells, CD14 monocytes, and CD16 monocytes as predictors of mortality with 90% accuracy. Finally, we validate our findings in an independent transcriptomics dataset and provide a framework to elucidate mechanisms that promote survival in critically ill COVID-19 patients. Identifying prognostic indicators among critical COVID-19 patients holds tremendous value in risk stratification and clinical management.
bioRxiv (Cold Spring Harbor Laboratory), Apr 29, 2023
Background: Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have re... more Background: 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 pathologically 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. Methods: We employed an established murine ICI myocarditis model (Ctla4 +/-Pdcd1-/mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, flow cytometry, in situ RNA hybridization and molecular imaging and antibody neutralization studies. Results: 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 highly 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) was found selectively expanded in patients with ICI myocarditis compared to other forms of heart failure and myocarditis. .
bioRxiv (Cold Spring Harbor Laboratory), Jul 9, 2021
Heart failure represents a major cause of morbidity and mortality worldwide. Single cell transcri... more Heart failure represents a major cause of morbidity and mortality worldwide. Single cell transcriptomics have revolutionized our understanding of cell composition and associated gene expression across human tissues. Through integrated analysis of single cell and single nucleus RNA sequencing data generated from 45 individuals, we define the cell composition of the healthy and failing human heart. We identify cell specific transcriptional signatures of heart failure and reveal the emergence of disease associated cell states. Intriguingly, cardiomyocytes converge towards a common disease associated cell state, while fibroblasts and myeloid cells undergo dramatic diversification. Endothelial cells and pericytes display global transcriptional shifts without changes in cell complexity. Collectively, our findings provide a comprehensive analysis of the cellular and transcriptomic landscape of human heart failure, identify cell type specific transcriptional programs and states associated with disease, and establish a valuable resource for the investigation of human heart failure.
Idiopathic pulmonary fibrosis (IPF) is a progressive, inflammatory lung disease that is monitored... more Idiopathic pulmonary fibrosis (IPF) is a progressive, inflammatory lung disease that is monitored clinically by measures of lung function, without effective molecular markers of disease activity or therapeutic efficacy. Lung immune cells active in the pro-fibrotic process include inflammatory monocyte and interstitial macrophages that express the CC motif chemokine receptor 2 (CCR2). CCR2 + monocyte lung influx is essential for disease phenotypes in models of fibrosis and identified in lungs from subjects with IPF. Here, we show that our peptide-based radiotracer 64 Cu-DOTA-ECL1i identifies CCR2 + inflammatory monocytes and interstitial macrophages in multiple preclinical mouse models of lung fibrosis, using positron emission tomography (PET) imaging. Mice with bleomycin-induced fibrosis treated with blocking antibodies to interleukin-1b, a mediator of fibrosis associated with CCR2 + cell inflammation, or with pirfenidone, an approved anti-fibrotic agent, demonstrated decreased CCR2-dependent interstitial macrophage accumulation and reduced 64 Cu-DOTA-ECL1i PET uptake, compared to controls. Lung tissues from patients with fibrotic lung disease demonstrated abundant CCR2 + cells surrounding regions of fibrosis, and an ex vivo tissue-binding assay showed correlation between radiotracer localization and CCR2 + cells. In a phase 0/1 clinical study of 64 Cu-DOTA-ECL1i PET, healthy volunteers showed little lung uptake, while subjects with pulmonary fibrosis exhibited increased uptake, notably in zones of subpleural fibrosis, reflecting the distribution of CCR2 + cells in the profibrotic niche. These findings support a pathologic role of inflammatory lung monocytes/macrophages in fibrotic lung disease and the translational use of 64 Cu-DOTA-ECL1i PET to track CCR2-specific inflammation for image-guided therapy.
Solid organ transplant represents a potentially lifesaving procedure for patients suffering from ... more Solid organ transplant represents a potentially lifesaving procedure for patients suffering from end-stage heart, lung, liver, and kidney failure. However, rejection remains a significant source of morbidity and immunosuppressive medications have significant toxicities. Janus kinase (JAK) inhibitors are effective immunosuppressants in autoimmune diseases and graft versus host disease after allogeneic hematopoietic cell transplantation. Here we examine the role of JAK inhibition in preclinical fully major histocompatibility mismatched skin and heart allograft models. Baricitinib combined with cyclosporine A (CsA) preserved fully major histocompatibility mismatched skin grafts for the entirety of a 111-day experimental period. In baricitinib plus CsA treated mice, circulating CD4+T-bet+ T cells, CD8+T-bet+ T cells, and CD4+FOXP3+ regulatory T cells were reduced. Single cell RNA sequencing revealed a unique expression profile in immune cells in the skin of baricitinib plus CsA treated ...
Background: Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have re... more Background: 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. Methods: We employed an established murine ICI myocarditis model (Ctla4+/-Pdcd1-/- mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, flow cytometry, in situ RNA hybridization and molecular imaging and antibody neutralization studies. Results: We observed marked increases in CCR2+ monocyte-derived mac...
Background Immune checkpoint inhibitor (ICI) myocarditis is associated with high morbidity and mo... more Background Immune checkpoint inhibitor (ICI) myocarditis is associated with high morbidity and mortality. While endomyocardial biopsy (EMB) is considered a gold standard for diagnosis, the sensitivity of EMB is not well defined. Additionally, the pathological features that correlate with the clinical diagnosis of ICI-associated myocarditis remain incompletely understood. Methods We retrospectively identified and reviewed the clinicopathological features of 26 patients with suspected ICI-associated myocarditis based on institutional major and minor criteria. Seventeen of these patients underwent EMB, and the histopathological features were assessed by routine hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for CD68, a macrophage marker. Results Only 2/17 EMBs obtained from patients with suspected ICI myocarditis satisfied the Dallas criteria. Supplemental IHC staining and quantification of CD68+ macrophages identified an additional 7 patients with patholog...
Highlights d ImmGen monomuclear phagocyte open-source (MNP OS) dataset is introduced (337 samples... more Highlights d ImmGen monomuclear phagocyte open-source (MNP OS) dataset is introduced (337 samples) d Myeloid mouse scRNA-seq dataset across tissues is assembled based on Tabula Muris d GAM clustering is metabolic network analysis of the largescale/single-cell data d Tissue-/cell-specific cholesterol, glycolysis, nucleotide, GSH/lipid modules reported
Inflammation and tissue fibrosis co-exist and are causally linked to organ dysfunction. However, ... more Inflammation and tissue fibrosis co-exist and are causally linked to organ dysfunction. However, the molecular mechanisms driving immune-fibroblast crosstalk in human cardiac disease remains unexplored and there are currently no therapeutics to target fibrosis. Here, we performed multi-omic single-cell gene expression, epitope mapping, and chromatin accessibility profiling in 38 donors, acutely infarcted, and chronically failing human hearts. We identified a disease-associated fibroblast trajectory marked by cell surface expression of fibroblast activator protein (FAP), which diverged into distinct myofibroblasts and pro-fibrotic fibroblast populations, the latter resembling matrifibrocytes. Pro-fibrotic fibroblasts were transcriptionally similar to cancer associated fibroblasts and expressed high levels of collagens and periostin (POSTN), thymocyte differentiation antigen 1 (THY-1), and endothelin receptor A (EDNRA) predicted to be driven by a RUNX1 gene regulatory network. We asse...
Cardiac fibrosis is causally linked to heart failure pathogenesis and adverse clinical outcomes. ... more Cardiac fibrosis is causally linked to heart failure pathogenesis and adverse clinical outcomes. However, the precise fibroblast populations that drive fibrosis in the human heart and the mechanisms that govern their emergence remain incompletely defined. Here, we performed Cellular Indexing of Transcriptomes and Epitomes by sequencing (CITE-seq) in 22 explanted human hearts from healthy donors, acute myocardial infarction (MI), and chronic ischemic and non-ischemic cardiomyopathy patients. We identified a fibroblast trajectory marked by fibroblast activator protein (FAP) and periostin (POSTN) expression that was independent of myofibroblasts, peaked early after MI, remained elevated in chronic heart failure, and displayed a transcriptional signature consistent with fibrotic activity. We assessed the applicability of cardiac fibrosis models and demonstrated that mouse MI, angiotensin II/phenylephrine infusion, and pressure overload models were superior compared to cultured human hea...
Cardiac macrophages orchestrate inflammatory responses following myocardial injury and represent ... more Cardiac macrophages orchestrate inflammatory responses following myocardial injury and represent powerful determinants of cardiac tissue remodeling and outcomes. Following myocardial infarction, large numbers of monocytes are recruited to the heart, infiltrate into the myocardium, and differentiate into diverse populations of macrophages and dendritic cells with divergent inflammatory and reparative transcriptional signatures. The molecular mechanisms that drive monocyte fate decisions in the injured heart remained to be defined. Here, we tested the hypothesis that macrophage hypoxia sensing regulates monocyte differentiation and cardiac remodeling following myocardial infarction. Using a mouse model of ischemia reperfusion injury, we uncovered that deletion of the hypoxia sensor, Hif1a, in macrophages resulted in increased infarct size and accelerated adverse remodeling without impacting coronary angiogenesis. Single cell RNA sequencing revealed that loss of macrophage hypoxia sens...
bioRxiv (Cold Spring Harbor Laboratory), Mar 16, 2024
Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit an... more Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1/PD-L1, CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here, we leveraged genetic mouse models, single cell sequencing, and cell depletion studies to demonstrate that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2 + macrophages and subsequent recruitment of effector memory CD8 T-cells. We identify a positive feedback loop between CCR2 + macrophages and CD8 T-cells driven by IL12b, TNF, and IFN-γ signaling that promotes myocardial inflammation and show that prior exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates LV remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.
bioRxiv (Cold Spring Harbor Laboratory), Dec 24, 2023
Inflammation contributes to the pathogenesis of cardiac disease and represents a viable therapeut... more Inflammation contributes to the pathogenesis of cardiac disease and represents a viable therapeutic target for heart failure. Cardiac injury elicits recruitment of neutrophils, monocytes, and T-cells. Monocytes and their progeny represent are highly abundant, display incredible functional diversity, and are key determinants of myocardial inflammation. Much remains to be learned regarding mechanisms and signaling events that instruct monocyte fate decisions. We devised a genetic lineage tracing strategy using Ccr2 crERT2 Rosa2 LSL-tdTomato mice in combination with single cell RNA-sequencing to map the fate and differentiation trajectories of monocytes that infiltrate the heart after reperfused myocardial infarction (MI). We observe that monocyte recruitment is restricted to the first 5 days following MI. Infiltrating monocytes give rise to transcriptionally distinct and spatially restricted macrophage and dendritic cell-like subsets, dynamically shift over time, and chronically persist within the myocardium. Pseudotime analysis predicted two differentiation trajectories of monocyte-derived macrophages that are initially partitioned into the border and infarct zones, respectively. Among these trajectories, we show that macrophages expressing a type I IFN responsive signature are an intermediate population localized within the border zone and promote myocardial protection. Collectively, these data uncover new complexities of monocyte differentiation in the infarcted heart and suggest that modulating monocyte fate decisions may have clinical implications.
HIGHLIGHTS SARS-CoV-2 directly infects cardiomyocytes in patients with COVID-19 myocarditis and d... more HIGHLIGHTS SARS-CoV-2 directly infects cardiomyocytes in patients with COVID-19 myocarditis and does not infect cardiac macrophages, fibroblasts, or endothelial cells. COVID-19 myocarditis is characterized by a myeloid-rich inflammatory infiltrate. SARS-CoV-2 infects cardiomyocytes through an ACE2 and endosomal cysteine protease dependent pathway. Infection of hPSC-derived cardiomyocytes and engineered heart tissues show that cytokine production, sarcomere disassembly, and cell death were a direct consequence of cardiomyocyte infection. SARS-CoV-2 reduces cardiomyocyte contractility through sarcomere breakdown and cardiomyocyte cell death.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
SARS-CoV-2 triggers a complex systemic immune response in circulating blood mononuclear cells. Th... more SARS-CoV-2 triggers a complex systemic immune response in circulating blood mononuclear cells. The relationship between immune cell activation of the peripheral compartment and survival in critical COVID-19 remains to be established. Here we use single-cell RNA sequencing and Cellular Indexing of Transcriptomes and Epitomes by sequence mapping to elucidate cell type specific transcriptional signatures that associate with and predict survival in critical COVID-19. Patients who survive infection display activation of antibody processing, early activation response, and cell cycle regulation pathways most prominent within B-, T-, and NK-cell subsets. We further leverage cell specific differential gene expression and machine learning to predict mortality using single cell transcriptomes. We identify interferon signaling and antigen presentation pathways within cDC2 cells, CD14 monocytes, and CD16 monocytes as predictors of mortality with 90% accuracy. Finally, we validate our findings in an independent transcriptomics dataset and provide a framework to elucidate mechanisms that promote survival in critically ill COVID-19 patients. Identifying prognostic indicators among critical COVID-19 patients holds tremendous value in risk stratification and clinical management.
bioRxiv (Cold Spring Harbor Laboratory), Apr 29, 2023
Background: Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have re... more Background: 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 pathologically 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. Methods: We employed an established murine ICI myocarditis model (Ctla4 +/-Pdcd1-/mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, flow cytometry, in situ RNA hybridization and molecular imaging and antibody neutralization studies. Results: 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 highly 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) was found selectively expanded in patients with ICI myocarditis compared to other forms of heart failure and myocarditis. .
bioRxiv (Cold Spring Harbor Laboratory), Jul 9, 2021
Heart failure represents a major cause of morbidity and mortality worldwide. Single cell transcri... more Heart failure represents a major cause of morbidity and mortality worldwide. Single cell transcriptomics have revolutionized our understanding of cell composition and associated gene expression across human tissues. Through integrated analysis of single cell and single nucleus RNA sequencing data generated from 45 individuals, we define the cell composition of the healthy and failing human heart. We identify cell specific transcriptional signatures of heart failure and reveal the emergence of disease associated cell states. Intriguingly, cardiomyocytes converge towards a common disease associated cell state, while fibroblasts and myeloid cells undergo dramatic diversification. Endothelial cells and pericytes display global transcriptional shifts without changes in cell complexity. Collectively, our findings provide a comprehensive analysis of the cellular and transcriptomic landscape of human heart failure, identify cell type specific transcriptional programs and states associated with disease, and establish a valuable resource for the investigation of human heart failure.
Idiopathic pulmonary fibrosis (IPF) is a progressive, inflammatory lung disease that is monitored... more Idiopathic pulmonary fibrosis (IPF) is a progressive, inflammatory lung disease that is monitored clinically by measures of lung function, without effective molecular markers of disease activity or therapeutic efficacy. Lung immune cells active in the pro-fibrotic process include inflammatory monocyte and interstitial macrophages that express the CC motif chemokine receptor 2 (CCR2). CCR2 + monocyte lung influx is essential for disease phenotypes in models of fibrosis and identified in lungs from subjects with IPF. Here, we show that our peptide-based radiotracer 64 Cu-DOTA-ECL1i identifies CCR2 + inflammatory monocytes and interstitial macrophages in multiple preclinical mouse models of lung fibrosis, using positron emission tomography (PET) imaging. Mice with bleomycin-induced fibrosis treated with blocking antibodies to interleukin-1b, a mediator of fibrosis associated with CCR2 + cell inflammation, or with pirfenidone, an approved anti-fibrotic agent, demonstrated decreased CCR2-dependent interstitial macrophage accumulation and reduced 64 Cu-DOTA-ECL1i PET uptake, compared to controls. Lung tissues from patients with fibrotic lung disease demonstrated abundant CCR2 + cells surrounding regions of fibrosis, and an ex vivo tissue-binding assay showed correlation between radiotracer localization and CCR2 + cells. In a phase 0/1 clinical study of 64 Cu-DOTA-ECL1i PET, healthy volunteers showed little lung uptake, while subjects with pulmonary fibrosis exhibited increased uptake, notably in zones of subpleural fibrosis, reflecting the distribution of CCR2 + cells in the profibrotic niche. These findings support a pathologic role of inflammatory lung monocytes/macrophages in fibrotic lung disease and the translational use of 64 Cu-DOTA-ECL1i PET to track CCR2-specific inflammation for image-guided therapy.
Solid organ transplant represents a potentially lifesaving procedure for patients suffering from ... more Solid organ transplant represents a potentially lifesaving procedure for patients suffering from end-stage heart, lung, liver, and kidney failure. However, rejection remains a significant source of morbidity and immunosuppressive medications have significant toxicities. Janus kinase (JAK) inhibitors are effective immunosuppressants in autoimmune diseases and graft versus host disease after allogeneic hematopoietic cell transplantation. Here we examine the role of JAK inhibition in preclinical fully major histocompatibility mismatched skin and heart allograft models. Baricitinib combined with cyclosporine A (CsA) preserved fully major histocompatibility mismatched skin grafts for the entirety of a 111-day experimental period. In baricitinib plus CsA treated mice, circulating CD4+T-bet+ T cells, CD8+T-bet+ T cells, and CD4+FOXP3+ regulatory T cells were reduced. Single cell RNA sequencing revealed a unique expression profile in immune cells in the skin of baricitinib plus CsA treated ...
Background: Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have re... more Background: 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. Methods: We employed an established murine ICI myocarditis model (Ctla4+/-Pdcd1-/- mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, flow cytometry, in situ RNA hybridization and molecular imaging and antibody neutralization studies. Results: We observed marked increases in CCR2+ monocyte-derived mac...
Background Immune checkpoint inhibitor (ICI) myocarditis is associated with high morbidity and mo... more Background Immune checkpoint inhibitor (ICI) myocarditis is associated with high morbidity and mortality. While endomyocardial biopsy (EMB) is considered a gold standard for diagnosis, the sensitivity of EMB is not well defined. Additionally, the pathological features that correlate with the clinical diagnosis of ICI-associated myocarditis remain incompletely understood. Methods We retrospectively identified and reviewed the clinicopathological features of 26 patients with suspected ICI-associated myocarditis based on institutional major and minor criteria. Seventeen of these patients underwent EMB, and the histopathological features were assessed by routine hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) staining for CD68, a macrophage marker. Results Only 2/17 EMBs obtained from patients with suspected ICI myocarditis satisfied the Dallas criteria. Supplemental IHC staining and quantification of CD68+ macrophages identified an additional 7 patients with patholog...
Highlights d ImmGen monomuclear phagocyte open-source (MNP OS) dataset is introduced (337 samples... more Highlights d ImmGen monomuclear phagocyte open-source (MNP OS) dataset is introduced (337 samples) d Myeloid mouse scRNA-seq dataset across tissues is assembled based on Tabula Muris d GAM clustering is metabolic network analysis of the largescale/single-cell data d Tissue-/cell-specific cholesterol, glycolysis, nucleotide, GSH/lipid modules reported
Inflammation and tissue fibrosis co-exist and are causally linked to organ dysfunction. However, ... more Inflammation and tissue fibrosis co-exist and are causally linked to organ dysfunction. However, the molecular mechanisms driving immune-fibroblast crosstalk in human cardiac disease remains unexplored and there are currently no therapeutics to target fibrosis. Here, we performed multi-omic single-cell gene expression, epitope mapping, and chromatin accessibility profiling in 38 donors, acutely infarcted, and chronically failing human hearts. We identified a disease-associated fibroblast trajectory marked by cell surface expression of fibroblast activator protein (FAP), which diverged into distinct myofibroblasts and pro-fibrotic fibroblast populations, the latter resembling matrifibrocytes. Pro-fibrotic fibroblasts were transcriptionally similar to cancer associated fibroblasts and expressed high levels of collagens and periostin (POSTN), thymocyte differentiation antigen 1 (THY-1), and endothelin receptor A (EDNRA) predicted to be driven by a RUNX1 gene regulatory network. We asse...
Cardiac fibrosis is causally linked to heart failure pathogenesis and adverse clinical outcomes. ... more Cardiac fibrosis is causally linked to heart failure pathogenesis and adverse clinical outcomes. However, the precise fibroblast populations that drive fibrosis in the human heart and the mechanisms that govern their emergence remain incompletely defined. Here, we performed Cellular Indexing of Transcriptomes and Epitomes by sequencing (CITE-seq) in 22 explanted human hearts from healthy donors, acute myocardial infarction (MI), and chronic ischemic and non-ischemic cardiomyopathy patients. We identified a fibroblast trajectory marked by fibroblast activator protein (FAP) and periostin (POSTN) expression that was independent of myofibroblasts, peaked early after MI, remained elevated in chronic heart failure, and displayed a transcriptional signature consistent with fibrotic activity. We assessed the applicability of cardiac fibrosis models and demonstrated that mouse MI, angiotensin II/phenylephrine infusion, and pressure overload models were superior compared to cultured human hea...
Cardiac macrophages orchestrate inflammatory responses following myocardial injury and represent ... more Cardiac macrophages orchestrate inflammatory responses following myocardial injury and represent powerful determinants of cardiac tissue remodeling and outcomes. Following myocardial infarction, large numbers of monocytes are recruited to the heart, infiltrate into the myocardium, and differentiate into diverse populations of macrophages and dendritic cells with divergent inflammatory and reparative transcriptional signatures. The molecular mechanisms that drive monocyte fate decisions in the injured heart remained to be defined. Here, we tested the hypothesis that macrophage hypoxia sensing regulates monocyte differentiation and cardiac remodeling following myocardial infarction. Using a mouse model of ischemia reperfusion injury, we uncovered that deletion of the hypoxia sensor, Hif1a, in macrophages resulted in increased infarct size and accelerated adverse remodeling without impacting coronary angiogenesis. Single cell RNA sequencing revealed that loss of macrophage hypoxia sens...
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Papers by Kory Lavine