Wolfgang Junger

Wolfgang Junger
Harvard Medical School | HMS · Department of Surgery

Professor

About

214
Publications
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Introduction
We study cellular immune responses in critical care patients with infections, sepsis, and multiple organ failure. One focus is on defective ATP signaling as a cause of immune dysfunction in theses patients.

Publications

Publications (214)
Article
Polymorphonuclear neutrophils (PMNs) protect the host from invading microorganisms. However, excessively activated PMNs can also cause damage to host tissues under inflammatory conditions. Here we developed simple assays to determine the activation state of PMNs in human whole blood that contains soluble mediators known to influence PMN functions....
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ATP released into the bloodstream regulates immune responses and other physiological functions. Excessive accumulation of extracellular ATP interferes with these functions, and elevated plasma ATP levels could indicate infections and other pathological disorders. However, there is considerable disagreement about what constitutes normal plasma ATP l...
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Rationale The increased mortality and morbidity seen in critically injured patients appears associated with systemic inflammatory response syndrome (SIRS) and immune dysfunction, which ultimately predisposes to infection. Mitochondria released by injury could generate danger molecules, for example, ATP, which in turn would be rapidly scavenged by e...
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Extracellular di- and tri-phosphate nucleotides are released from activated or injured cells to trigger vascular and immune P 2 purinergic receptors, provoking inflammation and vascular thrombosis. These metabokines are scavenged by ecto-nucleoside triphosphate diphosphohydrolase-1 (E-NTPDase1 or CD39). Further degradation of the mono-phosphate nuc...
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Microglia, the brain’s resident macrophages, help to regulate brain function by removing dying neurons, pruning non-functional synapses, and producing ligands that support neuronal survival1. Here we show that microglia are also critical modulators of neuronal activity and associated behavioural responses in mice. Microglia respond to neuronal acti...
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T cells must migrate to encounter antigen-presenting cells and perform their roles in host defense. Here, we found that autocrine stimulation of the purinergic receptor P2Y11 regulates the migration of human CD4 T cells. P2Y11 receptors redistributed from the front to the back of polarized cells where they triggered intracellular cAMP/PKA signals t...
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Intracellular ATP is the universal energy carrier that fuels many cellular processes. However, immune cells can also release a portion of their ATP into the extracellular space. There, ATP activates purinergic receptors that mediate autocrine and paracrine signaling events needed for the initiation, modulation, and termination of cell functions. Mi...
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T cells form an immune synapse (IS) with antigen-presenting cells (APCs) to detect antigens that match their TCR. Mitochondria, pannexin-1 (panx1) channels, and P2X4 receptors congregate at the IS where mitochondria produce the ATP that panx1 channels release in order to stimulate P2X4 receptors. P2X4 receptor stimulation causes cellular Ca2+ influ...
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Purinergic P2 receptors are critical regulators of several functions within the vascular system, including platelet aggregation, vascular inflammation, and vascular tone. However, a role for ATP release and P2Y receptor signalling in angiogenesis remains poorly defined. Here, we demonstrate that blood vessel growth is controlled by P2Y2 receptors....
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Background: Decreased tumor necrosis factor (TNF)-α production in whole blood following ex vivo lipopolysaccharide (LPS) stimulation indicates suppression of the toll-like receptor (TLR)4 pathway. This is associated with increased mortality in pediatric influenza critical illness. Whether anti-viral immune signaling pathways are also suppressed in...
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Chemosensory epithelial cells (EpCs) are specialized cells that promote innate type 2 immunity and protective neurally mediated reflexes in the airway. Their effector programs and modes of activation are not fully understood. Here, we define the transcriptional signature of two choline acetyltransferase–expressing nasal EpC populations. They are fo...
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Bacterial infections and sepsis are leading causes of morbidity and mortality in critically ill patients. Currently, there are no effective treatments available to improve clinical outcome in sepsis. Here, we elucidated a mechanism by which Escherichia coli (E. coli) bacteria impair neutrophil (PMN) chemotaxis and we studied whether this mechanism...
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Abstrct: Ischemia and reperfusion injury following severe trauma or cardiac arrest are major causes of organ damage in intensive care patients. The brain is particularly vulnerable because hypoxia rapidly damages neurons due to their heavy reliance on oxidative phosphorylation. Therapeutic hypothermia can reduce ischemia-induced brain damage, but...
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Previous studies have shown that T cell receptor (TCR) and CD28 coreceptor stimulation involves rapid ATP release, autocrine purinergic feedback via P2X receptors, and mitochondrial ATP synthesis that promote T cell activation. Here, we show that ADP formation and autocrine stimulation of P2Y1 receptors are also involved in these purinergic signali...
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T cell suppression contributes to immune dysfunction in sepsis. However, the underlying mechanisms are not well defined. Here, we show that exposure of human peripheral blood mononuclear cells to bacterial lipopolysaccharide (LPS) can rapidly and dose-dependently suppress interleukin-2 (IL-2) production and T cell proliferation. We also report that...
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Objectives: Monocytes and macrophages produce interleukin-1β by inflammasome activation which involves adenosine triphosphate release, pannexin-1 channels, and P2X7 receptors. However, interleukin-1β can also be produced in an inflammasome-independent fashion. Here we studied if this mechanism also involves adenosine triphosphate signaling and how...
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Cerebral and cardiac dysfunction cause morbidity and mortality in post-cardiac arrest syndrome (PCAS) patients. Predicting clinical outcome is necessary to provide the optimal level of life support for these patients. In this pilot study, we examined whether plasma ATP and adenylate levels have value in predicting clinical outcome in PCAS patients....
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T cells must migrate in order to encounter antigen-presenting cells (APCs) and to execute their varied functions in immune defense and inflammation. ATP release and autocrine signaling through purinergic receptors contribute to T cell activation at the immune synapse that T cells form with APCs. Here, we show that T cells also require ATP release a...
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Extracellular ATP (eATP) accumulation within the tumor microenvironment (TME) has the potential to activate purinergic signaling. The eATP evoked signaling effects bolster antitumor immune responses while exerting direct cytotoxicity on tumor cells and vascular endothelial cells, mediated at least in part through P2X7 receptors. Approaches to augme...
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In neutrophils, adenosine triphosphate (ATP) release and autocrine purinergic signaling regulate coordinated cell motility during chemotaxis. Here, we studied whether similar mechanisms regulate the motility of breast cancer cells. While neutrophils and benign human mammary epithelial cells (HMEC) form a single leading edge, MDA-MB-231 breast cance...
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Background Osteosarcoma is the most prevalent primary malignant bone tumor, but treatment is difficult and prognosis remains poor. Recently, large-dose chemotherapy has been shown to improve outcome but this approach can cause many side effects. Minimizing the dose of chemotherapeutic drugs and optimizing their curative effects is a current goal in...
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T cells respond to antigen stimulation with the rapid release of cellular ATP, which stimulates an autocrine feedback mechanism that regulates calcium influx through P2X receptors. This autocrine purinergic feedback mechanism plays an essential role in the activation of T cells resulting in cell proliferation and clonal expansion. We recently repor...
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Objective: Sepsis remains an unresolved clinical problem. Therapeutic strategies focusing on inhibition of neutrophils (polymorphonuclear neutrophils) have failed, which indicates that a more detailed understanding of the underlying pathophysiology of sepsis is required. Polymorphonuclear neutrophil activation and chemotaxis require cellular adeno...
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Purpose: Sepsis remains an unresolved clinical problem with high in-hospital mortality. Despite intensive research over decades, no treatments for sepsis have become available. Here we explore the role of ATP in the pathophysiology of sepsis. ATP is not only a universal energy carrier but it also acts as an extracellular signaling molecule that re...
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Interferon gamma (IFNγ 3)-producing CD8 + T cells (Tc1) play important roles in immunological disease. We now report that CD3/CD28-mediated stimulation of CD8 + T cells to generate Tc1 cells, not only increases IFNγ 3 production but also boosts the generation of reactive oxygen species (ROS) and augments expression of CD39. Inhibition of NADPH oxid...
Data
Supplementary Figures 1-13 and Supplementary Tables 1-2
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Exhausted T cells express multiple co-inhibitory molecules that impair their function and limit immunity to chronic viral infection. Defining novel markers of exhaustion is important both for identifying and potentially reversing T cell exhaustion. Herein, we show that the ectonucleotidse CD39 is a marker of exhausted CD8+ T cells. CD8+ T cells spe...
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Neutrophils use chemotaxis to locate invading bacteria. Adenosine triphosphate (ATP) release and autocrine purinergic signaling via P2Y2 receptors at the front and A2a receptors at the back of cells regulate chemotaxis. Here, we examined the intracellular mechanisms that control these opposing signaling mechanisms. We found that mitochondria delive...
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T cell suppression in sepsis is a well-known phenomenon; however, the underlying mechanisms are not fully understood. We previously reported that T cell stimulation involves mitochondrial ATP production that fuels purinergic signaling mechanisms necessary for adequate T cell responses. Here we show that basal mitochondrial ATP production, ATP relea...
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Hypertonic saline (HS) resuscitation has been studied as a possible strategy to reduce PMN activation and tissue damage in trauma patients. HS blocks PMNs by ATP release and stimulation of A2a adenosine receptors. Here we studied the underlying mechanisms in search of possible reasons for the inconsistent results of recent clinical trials with HS r...
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Impaired hemostasis frequently occurs following traumatic shock and resuscitation. The prehospital fluid administered can exacerbate subsequent bleeding and coagulopathy. Hypertonic solutions are recommended as first-line treatment of traumatic shock; however, their effects on coagulation are unclear. This study explores the impact of resuscitation...
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The activation of immune cells must be tightly regulated to allow an effective immune defense while limiting collateral damage to host tissues. Cellular ATP release and autocrine stimulation of purinergic receptors are recognized as critical regulators of immune cell activation. However, the study of purinergic signaling has been hampered by the sh...
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Shockwave treatment accelerates impaired wound healing in diverse clinical situations. However, the mechanisms underlying the beneficial effects of shockwaves have not yet been fully revealed. Since cell proliferation is a major requirement in the wound healing cascade, we used in vitro studies and an in vivo wound healing model to study whether sh...
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Polymorphonuclear neutrophils (PMNs) form the first line of defense against invading microorganisms. We have shown previously that ATP release and autocrine purinergic signaling via P2Y2 receptors are essential for PMN activation. Here we show that mitochondria provide the ATP that initiates PMN activation. Stimulation of formyl peptide receptors i...
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T cells play a central role in host defense. ATP release and autocrine feedback via purinergic receptors has been shown to regulate T cell function. However, the sources of the ATP that drives this process are not known. We found that stimulation of T cells triggers a spike in cellular ATP production that doubles intracellular ATP levels in <30 s a...
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Our previous work has shown that polymorphonuclear neutrophils (PMN) require cellular ATP release and autocrine purinergic signaling for their activation. Here we studied in a mouse model of cecal ligation and puncture (CLP) whether sepsis affects this purinergic signaling process and thereby alters PMN responses after sepsis. Using high performanc...
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Many preclinical studies in critical care medicine and related disciplines rely on hypothesis-driven research in mice. The underlying premise posits that mice sufficiently emulate numerous pathophysiological alterations produced by trauma/sepsis and can serve as an experimental platform for answering clinically relevant questions. Recently the lay...
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Activation of polymorphonuclear neutrophils (PMN) is thought to contribute to traumatic brain injury (TBI). Because hypertonic fluids can inhibit PMN activation, we studied whether hypertonic fluid resuscitation can reduce PMN activation in TBI patients. Trauma patients with severe TBI were resuscitated with 250 ml of either 7.5% hypertonic saline...
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Background: We sought to determine the quantitative expression of human leukocyte antigen-DR (HLA-DR) on monocytes in patients with acute intestinal bacterial infections and inflammatory bowel disease (IBD). Methods: The quantitative expression of HLA-DR on monocytes was determined by fluorescence-activated cell sorting analysis in patients with...
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Neutrophil chemotaxis requires excitatory signals at the front and inhibitory signals at the back of cells, which regulate cell migration in a chemotactic gradient field. We have previously shown that ATP release via pannexin 1 (PANX1) channels and autocrine stimulation of P2Y2 receptors contribute to the excitatory signals at the front. Here we sh...
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Shockwave treatment promotes bone healing of non-union fracture. In this study, we investigated whether this effect could be due to ATP release-induced differentiation of human mesenchymal stem cells (hMSCs) into osteoprogenitor cells. Cultured bone marrow-derived hMSCs were subjected to shockwave treatment and ATP release was assessed. Osteogenic...
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Background Extracellular adenosine triphosphate (ATP) functions as a novel danger signal that boosts antitumor immunity and can also directly kill tumor cells. We have previously reported that chronic exposure of tumor cells to ATP provokes P2X7-mediated tumor cell death, by as yet incompletely defined molecular mechanisms. Methodology/Principal F...
Data
Extracellular ATP is cytotoxic for B16/F10 melanoma cells. A–C) Dose- and time-dependent responses of B16/F10 cells to ATP killing: cell viability/proliferation CCK-8 (A); real-time cell growth by xCELLigence (B); and representative live cell images by Celligo (C). D) Dose-dependent induction of autophagy by ATP in B16/F10 cells, as determined by W...
Data
Time- and dose-dependent responses of AKT, AMPK and mTOR to ATP-mediated signaling responses in tumor cells. A) Western blots for AKT, AMPK and mTOR pathway components post ATP treatment at various times and doses in B16/F10 cells (A). B) AMPK inhibitor compound C (CC) fully rescued ATP-induced mTOR inhibition in MCA38 cells in a dose-dependent man...
Data
Assessment of carbenoxolone, N-acetyl-cysteine, Z-VAD-fmk, and necrostatin-1 on ATP-P2X7 induced signaling or tumor cell death. A) Effects of carbenoxolone (CBX) and N-acetyl-cysteine (NAC) on ATP-initiated AKT, AMPK and mTOR signaling in MCA38 and B16/F10 cells, as examined by Western blot analysis. B) Effects of Z-VAD-fmk and necrostatin-1 on ATP...
Data
Impact of calcium signaling on AKT, AMPK and mTOR signaling transduction and tumor cell growth. A) Effects of BAPTA-AM on AKT, AMPK and mTOR signaling in B16/F10 cells, as analyzed by Western blotting. B) Effects of BAPTA-AM on MCA38 cell growth, as examined by CCK-8 and expressed as percentage of untreated controls. C–D) Impacts of thapsigargin (T...
Data
P2 receptor agonist and antagonist studies. A) B16/F10 cell viability at 24 hr post BzATP treatment, as determined by CCK-8. Data are normalized to untreated controls. B) Effects of suramin (100 µM,) on AKT, AMPK and mTOR pathways in MCA38 cells, as examined by Western blot analysis. C–D) P2X7 antagonist KN62 counteracted ATP-evoked signaling trans...
Data
P2X7 deficient B16/F10 cells. A) Knockdown of P2X7 in B16/F10 cells was validated by Western blotting. B–F) Differential effects of ATP on control and P2X7 KD B16/F10 cells: AKT- and AMPK-mTOR signaling by Western blotting (B); cell viability by CCK-8 (C); representative live cell images by Celligo (D); and real-time monitoring of cell growth by xC...
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Objective: To study molecular mechanisms involved in hematopoietic stem cell (HSC) mobilization after liver resection and determine impacts on liver regeneration. Background: Extracellular nucleotide-mediated cell signaling has been shown to boost liver regeneration. Ectonucleotidases of the CD39 family are expressed by bone marrow-derived cells...
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Neutrophil chemotaxis requires local excitatory signals at the front and inhibitory signals at the back of cells. The mechanisms that link these signals are unknown. We previously showed that chemoattractants induce ATP release and excitatory purinergic feedback mechanisms at the front. Here we show that pannexin‐1 (panx1) is responsible for ATP re...
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Critically ill patients are routinely exposed to high levels of supplemental oxygen for prolonged periods of time, which can be life saving in the short term but also causes severe lung injury and increases mortality. To address this therapeutic dilemma, we have studied mechanisms of tissue-damaging effects of oxygen in mice. Unexpectedly, we show...
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Unlabelled: Liver cancer is associated with chronic inflammation, which is linked to immune dysregulation, disordered metabolism, and aberrant cell proliferation. Nucleoside triphosphate diphosphohydrolase-1; (CD39/ENTPD1) is an ectonucleotidase that regulates extracellular nucleotide/nucleoside concentrations by scavenging nucleotides to ultimate...
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Posttraumatic inflammation and excessive neutrophil activation cause multiple organ dysfunction syndrome (MODS), a major cause of death among hemorrhagic shock patients. Traditional resuscitation strategies may exacerbate inflammation; thus, novel fluid treatments are needed to reduce such posttraumatic complications. Hypertonic resuscitation fluid...
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Circulating human γδ T cells release ATP upon in vitro stimulation, which signals through P2X4 receptors and governs these cellsˈ function. Purinergic signaling plays a key role in a variety of physiological functions, including regulation of immune responses. Conventional αβ T cells release ATP upon TCR cross-linking; ATP binds to purinergic recep...
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Polymorphonuclear neutrophils (PMNs) generate reactive oxygen species (ROS) during phagocytosis and in response to soluble agonists. This functional response, termed oxidative burst, contributes to host defense, but it can also result in collateral damage of host tissues. To study this important PMN response, different methods have been developed t...
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Bacterial DNA (bDNA) contains hypomethylated "CpG" repeats that can be recognized by Toll-like receptor 9 (TLR-9) as a pathogen-associated molecular pattern. The ability of bDNA to initiate lung injury via TLR-9 has been inferred on the basis of studies using artificial CpG DNA. But the role of authentic bDNA in lung injury is still unknown. Moreov...