Genome-scale spatial mapping of the Hodgkin lymphoma microenvironment identifies tumor cell survival factors.

A key challenge in cancer research is to identify the secreted factors that contribute to tumor cell survival. Nowhere is this more evident than in Hodgkin lymphoma, where malignant Hodgkin Reed Sternberg (HRS) cells comprise only 1-5% of the tumor mass, the remainder being infiltrating immune cells that presumably are required for the survival of the HRS cells. Until now, there has been no way to characterize the complex Hodgkin lymphoma tumor microenvironment at genome scale.

SIRPα - CD47 axis regulates dendritic cell-T cell interactions and TCR activation during T cell priming in spleen.

The SIRPα-CD47 axis plays an important role in T cell recruitment to sites of immune reaction and inflammation but its role in T cell antigen priming is incompletely understood. Employing OTII TCR transgenic mice bred to Cd47-/- (Cd47KO) or SKI mice, a knock-in transgenic animal expressing non-signaling cytoplasmic-truncated SIRPα, we investigated how the SIRPα-CD47 axis contributes to antigen priming. Here we show that adoptive transfer of Cd47KO or SKI Ova-specific CD4+ T cells (OTII) into Cd47KO and SKI recipients, followed by Ova immunization, elicited reduced T cell division and proliferation indices, increased apoptosis, and reduced expansion compared to transfer into WT mice.

CD47 antibody blockade suppresses microglia-dependent phagocytosis and monocyte transition to macrophages, impairing recovery in EAE.

Experimental autoimmune encephalomyelitis (EAE) is a well-characterized animal model of multiple sclerosis. During the early phase of EAE, infiltrating monocytes and monocyte-derived macrophages contribute to T cell recruitment, especially CD4+ T cells, into the CNS, resulting in neuronal demyelination; however, in later stages, they promote remyelination and recovery by removal of myelin debris by phagocytosis. Signal regulatory protein α and CD47 are abundantly expressed in the CNS, and deletion of either molecule is protective in myelin oligodendrocyte glycoprotein-induced EAE because of failed effector T cell expansion and trafficking.

Endothelial STING controls T cell transmigration in an IFNI-dependent manner.

The stimulator of IFN genes (STING) protein senses cyclic dinucleotides released in response to double-stranded DNA and functions as an adaptor molecule for type I IFN (IFNI) signaling by activating IFNI-stimulated genes (ISG). We found impaired T cell infiltration into the peritoneum in response to TNF-α in global and EC-specific STING-/- mice and discovered that T cell transendothelial migration (TEM) across mouse and human endothelial cells (EC) deficient in STING was strikingly reduced compared with control EC, whereas T cell adhesion was not impaired. STING-/- T cells showed no defect in TEM or adhesion to EC, or immobilized endothelial cell-expressed molecules ICAM1 and VCAM1, compared with WT T cells.

Eosinophils improve cardiac function after myocardial infarction.

Clinical studies reveal changes in blood eosinophil counts and eosinophil cationic proteins that may serve as risk factors for human coronary heart diseases. Here we report an increase of blood or heart eosinophil counts in humans and mice after myocardial infarction (MI), mostly in the infarct region. Genetic or inducible depletion of eosinophils exacerbates cardiac dysfunction, cell death, and fibrosis post-MI, with concurrent acute increase of heart and chronic increase of splenic neutrophils and monocytes.

Neutrophil expressed CD47 regulates CD11b/CD18-dependent neutrophil transepithelial migration in the intestine in vivo.

Dysregulated neutrophil (PMN) transmigration across epithelial surfaces (TEpM) significantly contributes to chronic inflammatory diseases, yet mechanisms defining this process remain poorly understood. In the intestine, uncontrolled PMN TEpM is a hallmark of disease flares in ulcerative colitis. Previous in vitro studies directed at identifying molecular determinants that mediate TEpM have shown that plasma membrane proteins including CD47 and CD11b/CD18 play key roles in regulating PMN TEpM across monolayers of intestinal epithelial cells.

Targeted inhibition of CD47-SIRPα requires Fc-FcγR interactions to maximize activity in T-cell lymphomas.

Antibodies that bind CD47 on tumor cells and prevent interaction with SIRPα on phagocytes are active against multiple cancer types including T-cell lymphoma (TCL). Here we demonstrate that surface CD47 is heterogeneously expressed across primary TCLs, whereas major histocompatibility complex (MHC) class I, which can also suppress phagocytosis, is ubiquitous. Multiple monoclonal antibodies (mAbs) that block CD47-SIRPα interaction promoted phagocytosis of TCL cells, which was enhanced by cotreatment with antibodies targeting MHC class I.

Increased lymphocyte activation and atherosclerosis in CD47-deficient mice.

CD47, also known as integrin-associated protein (IAP), is a transmembrane protein with multiple biological functions including regulation of efferocytosis and leukocyte trafficking. In this study we investigated the effect of CD47-deficiency on atherosclerosis using a model of adeno-associated virus (AAV)-induced hypercholesterolemia. We observed increased plaque formation in CD47 null mice compared to wild-type controls.

Community Engagement in Academic Health Centers: A Model for Capturing and Advancing Our Successes.

Community engagement (CE) has come to the forefront of academic health centers' (AHCs) work because of two recent trends: the shift from a more traditional 'treatment of disease' model of health care to a population health paradigm (Gourevitch, 2014), and increased calls from funding agencies to include CE in research activities (Bartlett, Barnes, & McIver, 2014). As defined by the Centers for Disease Control and Prevention, community engagement is "the process of working collaboratively with and through groups of people affiliated by geographic proximity, special interest, or similar situations to address issues affecting the well-being of those people" (Centers for Disease Control and Prevention (CDC), 1997, p. 9).

Neutrophil Extracellular Traps Induce Endothelial Cell Activation and Tissue Factor Production Through Interleukin-1α and Cathepsin G.

Objective- Coronary artery thrombosis can occur in the absence of plaque rupture because of superficial erosion. Erosion-prone atheromata associate with more neutrophil extracellular traps (NETs) than lesions with stable or rupture-prone characteristics. The effects of NETs on endothelial cell (EC) inflammatory and thrombogenic properties remain unknown.

Complement C5a Receptor is the Key Initiator of Neutrophil Adhesion Igniting Immune Complex-induced Arthritis.

The deposition of immune complexes (IC) in tissues induces a "type III hypersensitivity" that results in tissue damage and underlies the pathogenesis of many autoimmune diseases. The neutrophil is the first immune cell recruited into sites of IC deposition and plays a critical role in shaping the overall tissue response. However, the mechanism by which IC and neutrophil infiltration into tissue is not known.

Defects in CD4+ T cell LFA-1 integrin-dependent adhesion and proliferation protect Cd47-/- mice from EAE.

CD47 is known to play an important role in CD4 T cell homeostasis. We recently reported a reduction in mice deficient in the Cd47 gene (Cd47) CD4 T cell adhesion and transendothelial migration (TEM) in vivo and in vitro as a result of impaired expression of high-affinity forms of LFA-1 and VLA-4 integrins. A prior study concluded that Cd47 mice were resistant to experimental autoimmune encephalomyelitis (EAE) as a result of complete failure in CD4 T cell activation after myelin oligodendrocyte glycoprotein peptide 35-55 aa (MOG) immunization.

Introduction for the special issue on "Tissue Barriers in Inflammation".

This issue of Tissue Barriers contains the inaugural special issue devoted to recent advances in barrier function of endothelial and epithelial cells. We used this opportunity to invite experts in vascular endothelial cell biology and epithelial cell biology to comment on critical questions and problems in permeability of organ and tissue barriers, and to provide insight into common areas in these fields, namely how these cells maintain homeostasis and response to injury and infection. To complement these reviews, this issue also contains four research articles that explore specific questions related respiratory and intestinal epithelial cell function.

NF-κB directs dynamic super enhancer formation in inflammation and atherogenesis.

Proinflammatory stimuli elicit rapid transcriptional responses via transduced signals to master regulatory transcription factors. To explore the role of chromatin-dependent signal transduction in the atherogenic inflammatory response, we characterized the dynamics, structure, and function of regulatory elements in the activated endothelial cell epigenome. Stimulation with tumor necrosis factor alpha prompted a dramatic and rapid global redistribution of chromatin activators to massive de novo clustered enhancer domains.

Piloting a nationally disseminated, interactive human subjects protection program for community partners: unexpected lessons learned from the field.

Funders, institutions, and research organizations are increasingly recognizing the need for human subjects protections training programs for those engaged in academic research. Current programs tend to be online and directed toward an audience of academic researchers. Research teams now include many nonacademic members, such as community partners, who are less likely to respond to either the method or the content of current online trainings.

Leukocyte recruitment in inflammation: basic concepts and new mechanistic insights based on new models and microscopic imaging technologies.

The immune cell system is a critical component of host defense. Recruitment of immune cells to sites of infection, immune reaction, or injury is complex and involves coordinated adhesive interactions between the leukocyte and the endothelial cell monolayer that lines blood vessels. This article reviews basic mechanisms in the recruitment of leukocytes to tissues and then selectively reviews new concepts that are emerging based on advances in live cell imaging microscopy and mouse strains.

Evaluating community engagement in an academic medical center.

From the perspective of academic medical centers (AMCs), community engagement is a collaborative process of working toward mutually defined goals to improve the community's health, and involves partnerships between AMCs, individuals, and entities representing the surrounding community. AMCs increasingly recognize the importance of community engagement, and recent programs such as Prevention Research Centers and Clinical and Translational Science Awards have highlighted community engagement activities. However, there is no standard or accepted metric for evaluating AMCs' performance and impact of community engagement activities.

Functional vascular endothelium derived from human induced pluripotent stem cells.

Vascular endothelium is a dynamic cellular interface that displays a unique phenotypic plasticity. This plasticity is critical for vascular function and when dysregulated is pathogenic in several diseases. Human genotype-phenotype studies of endothelium are limited by the unavailability of patient-specific endothelial cells.

CD47 plays a critical role in T-cell recruitment by regulation of LFA-1 and VLA-4 integrin adhesive functions.

CD47 plays an important but incompletely understood role in the innate and adaptive immune responses. CD47, also called integrin-associated protein, has been demonstrated to associate in cis with β1 and β3 integrins. Here we test the hypothesis that CD47 regulates adhesive functions of T-cell α4β1 (VLA-4) and αLβ2 (LFA-1) in in vivo and in vitro models of inflammation.

Novel role of CD47 in rat microvascular endothelium: signaling and regulation of T-cell transendothelial migration.

Objective: Although endothelial CD47, a member of the immunoglobulin superfamily, has been implicated in leukocyte diapedesis, its capacity for intracellular signaling and physical localization during this process has not been addressed in detail. This study examined endothelial CD47 spatiotemporal behavior and signaling pathways involved in regulating T-cell transendothelial migration.

Approach And Results: By biochemical methods, transmigration assays, and live-cell microscopy techniques, we show that endothelial CD47 engagement results in intracellular calcium mobilization, increased permeability, and activation of Src and AKT1/phosphoinositide 3-kinase in brain microvascular endothelial cells.

Endothelial epsin deficiency decreases tumor growth by enhancing VEGF signaling.

Epsins are a family of ubiquitin-binding, endocytic clathrin adaptors. Mice lacking both epsins 1 and 2 (Epn1/2) die at embryonic day 10 and exhibit an abnormal vascular phenotype. To examine the angiogenic role of endothelial epsins, we generated mice with constitutive or inducible deletion of Epn1/2 in vascular endothelium.

Endothelial CD47 promotes vascular endothelial-cadherin tyrosine phosphorylation and participates in T cell recruitment at sites of inflammation in vivo.

At sites of inflammation, endothelial adhesion molecules bind leukocytes and transmit signals required for transendothelial migration (TEM). We previously reported that adhesive interactions between endothelial cell CD47 and leukocyte signal regulatory protein γ (SIRPγ) regulate human T cell TEM. The role of endothelial CD47 in T cell TEM in vivo, however, has not been explored.

p120-Catenin prevents neutrophil transmigration independently of RhoA inhibition by impairing Src dependent VE-cadherin phosphorylation.

Leukocyte transendothelial migration (TEM) is regulated by several signaling pathways including Src family kinases (SFK) and the small RhoGTPases. Previous studies have shown that vascular endothelial-cadherin (VE-cad) forms a complex with β-,γ-, and p120-catenins and this complex disassociates to form a transient gap during leukocyte TEM. Additionally, p120-catenin (p120-1A) overexpression in human umbilical vein endothelial cells (HUVEC) stabilizes VE-cad surface expression, prevents tyrosine phosphorylation of VE-cad, and inhibits leukocyte TEM.

IL-17 and TNF-α sustain neutrophil recruitment during inflammation through synergistic effects on endothelial activation.

IL-17A (IL-17) is the signature cytokine produced by Th17 cells and has been implicated in host defense against infection and the pathophysiology of autoimmunity and cardiovascular disease. Little is known, however, about the influence of IL-17 on endothelial activation and leukocyte influx to sites of inflammation. We hypothesized that IL-17 would induce a distinct pattern of endothelial activation and leukocyte recruitment when compared with the Th1 cytokine IFN-γ.