Yoshiko Iwamoto

Harvard Medical School, Boston, Massachusetts, United States

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Publications (44)673.18 Total impact

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    ABSTRACT: Myeloperoxidase (MPO), a highly oxidative enzyme secreted by leukocytes has been implicated in human and experimental non-alcoholic steatohepatitis (NASH), but the underlying mechanisms remain unknown. Here, we investigated how MPO contributes to progression from steatosis to NASH. In C57Bl/6J mice fed a diet deficient in methionine and choline to induce NASH, neutrophils and to a lesser extent inflammatory monocytes are markedly increased compared to sham mice, and secrete abundant amounts of MPO. Through generation of HOCl, MPO directly causes hepatocyte death in vivo. In vitro experiments demonstrate mitochondrial permeability transition pore induction via activation of SAPK/JNK and PARP. MPO also contributes to activation of HSCs, the most important source of collagen in the liver. In vitro MPO-activated HSCs have an activation signature (MAPK and PI3K-AKT phosphorylation), and upregulate COL1A1, α-SMA, and CXCL1. MPO-derived oxidative stress also activates TGF-β in vitro, and TGF-β signaling inhibition with SB-431542 decreased steatosis and fibrosis in vivo. Conversely, congenital absence of MPO results in reduced hepatocyte injury, decreased levels of TGF-β, fewer activated HSCs, and less severe fibrosis in vivo. Innovation and Conclusion: Cumulatively, these findings demonstrate important cross talk between inflammatory myeloid cells, hepatocytes, and HSCs via MPO, and establish MPO as part of a pro-apoptotic and pro-fibrotic pathway of progression in NASH, as well as a potential therapeutic target to ameliorate this disease.
    Antioxidants & Redox Signaling 05/2015; DOI:10.1089/ars.2014.6108 · 7.67 Impact Factor
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    ABSTRACT: Following myocardial infarction (MI), myeloid cells derived from the hematopoietic system drive a sharp increase in systemic leukocyte levels that correlates closely with mortality. The origin of these myeloid cells, and the response of hematopoietic stem and progenitor cells (HSPCs) to MI, however, is unclear. Here, we identify a CCR2(+)CD150(+)CD48(-) LSK hematopoietic subset as the most upstream contributor to emergency myelopoiesis after ischemic organ injury. This subset has 4-fold higher proliferation rates than CCR2(-)CD150(+)CD48(-) LSK cells, displays a myeloid differentiation bias, and dominates the migratory HSPC population. We further demonstrate that the myeloid translocation gene 16 (Mtg16) regulates CCR2(+) HSPC emergence. Mtg16(-/-) mice have decreased levels of systemic monocytes and infarct-associated macrophages and display compromised tissue healing and post-MI heart failure. Together, these data provide insights into regulation of emergency hematopoiesis after ischemic injury and identify potential therapeutic targets to modulate leukocyte output after MI. Copyright © 2015 Elsevier Inc. All rights reserved.
    Cell stem cell 05/2015; 16(5):477-87. DOI:10.1016/j.stem.2015.04.008 · 22.15 Impact Factor
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    ABSTRACT: Quantification of cell-cycle state at a single-cell level is essential to understand fundamental three-dimensional (3D) biological processes such as tissue development and cancer. Analysis of 3D in vivo images, however, is very challenging. Today's best practice, manual annotation of select image events, generates arbitrarily sampled data distributions, which are unsuitable for reliable mechanistic inferences. Here, we present an integrated workflow for quantitative in vivo cell-cycle profiling. It combines image analysis and machine learning methods for automated 3D segmentation and cell-cycle state identification of individual cell-nuclei with widely varying morphologies embedded in complex tumor environments. We applied our workflow to quantify cell-cycle effects of three antimitotic cancer drugs over 8 d in HT-1080 fibrosarcoma xenografts in living mice using a data set of 38,000 cells and compared the induced phenotypes. In contrast to results with 2D culture, observed mitotic arrest was relatively low, suggesting involvement of additional mechanisms in their antitumor effect in vivo.
    Nature Methods 04/2015; 12(6). DOI:10.1038/nmeth.3363 · 25.95 Impact Factor
  • Journal of Experimental Medicine 04/2015; 212(4):497-512. DOI:10.1084/jem.20141642 · 13.91 Impact Factor
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    ABSTRACT: Sepsis is a frequently fatal condition characterized by an uncontrolled and harmful host reaction to microbial infection. Despite the prevalence and severity of sepsis, we lack a fundamental grasp of its pathophysiology. Here we report that the cytokine interleukin-3 (IL-3) potentiates inflammation in sepsis. Using a mouse model of abdominal sepsis, we showed that innate response activator B cells produce IL-3, which induces myelopoiesis of Ly-6C(high) monocytes and neutrophils and fuels a cytokine storm. IL-3 deficiency protects mice against sepsis. In humans with sepsis, high plasma IL-3 levels are associated with high mortality even after adjusting for prognostic indicators. This study deepens our understanding of immune activation, identifies IL-3 as an orchestrator of emergency myelopoiesis, and reveals a new therapeutic target for treating sepsis. Copyright © 2015, American Association for the Advancement of Science.
    Science 03/2015; Vol. 347(6227):1260-1265. DOI:10.1126/science.aaa4268 · 31.48 Impact Factor
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    ABSTRACT: Purpose To test if MPO myeloperoxidase -Gd, a gadolinium-based magnetic resonance (MR) imaging probe that is sensitive and specific for the proinflammatory and oxidative enzyme myeloperoxidase ( MPO myeloperoxidase ), which is secreted by certain inflammatory cells, is more sensitive than diethylenetriaminepentaacetic acid ( DTPA diethylenetriaminepentaacetic acid )-Gd in revealing early subclinical and chronic disease activity in the brain in experimental autoimmune encephalomyelitis ( EAE experimental autoimmune encephalomyelitis ), a mouse model of multiple sclerosis. Materials and Methods The protocol for animal experiments was approved by the institutional animal care committee. A total of 61 female SJL mice were induced with EAE experimental autoimmune encephalomyelitis . Mice underwent MPO myeloperoxidase -Gd- or DTPA diethylenetriaminepentaacetic acid -Gd-enhanced MR imaging on days 6, 8, and 10 after induction, before clinical disease develops, and during chronic disease at remission and the first relapse. Brains were harvested at these time points for flow cytometric evaluation of immune cell subtypes and immunohistochemistry. Statistical analysis was performed, and P < .05 was considered to indicate a significant difference. Results MPO myeloperoxidase -Gd helps detect earlier (5.2 vs 2.3 days before symptom onset, P = .004) and more (3.1 vs 0.3, P = .008) subclinical inflammatory lesions compared with DTPA diethylenetriaminepentaacetic acid -Gd, including in cases in which there was no evidence of overt blood-brain barrier ( BBB blood-brain barrier ) breakdown detected with DTPA diethylenetriaminepentaacetic acid -Gd enhancement. The number of MPO myeloperoxidase -Gd-enhancing lesions correlated with early infiltration of MPO myeloperoxidase -secreting monocytes and neutrophils into the brain (r = 0.91). MPO myeloperoxidase -Gd also helped detect more lesions during subclinical disease at remission (5.5 vs 1.3, P = .006) and at the first relapse (9.0 vs 2.7, P = .03) than DTPA diethylenetriaminepentaacetic acid -Gd, which also correlated well with the presence and accumulation of MPO myeloperoxidase -secreting inflammatory cells in the brain (r = 0.93). Conclusion MPO myeloperoxidase -Gd specifically reveals lesions with inflammatory monocytes and neutrophils, which actively secrete MPO myeloperoxidase . These results demonstrate the feasibility of detection of subclinical inflammatory disease activity in vivo, which is different from overt BBB blood-brain barrier breakdown. © RSNA, 2014 Online supplemental material is available for this article.
    Radiology 12/2014; 275(2):141495. DOI:10.1148/radiol.14141495 · 6.21 Impact Factor
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    ABSTRACT: Tumor-stromal interactions are a determining factor in cancer progression. In vivo, the interaction interface is associated with spatially-resolved distributions of cancer and stromal phenotypes. Here, we establish a micropatterned tumor-stromal assay (μTSA) with laser capture microdissection to control the location of co-cultured cells and analyze bulk and interfacial tumor-stromal signaling in driving cancer progression. μTSA reveals a spatial distribution of phenotypes in concordance with human estrogen receptor-positive (ER+) breast cancer samples, and heterogeneous drug activity relative to the tumor-stroma interface. Specifically, an unknown mechanism of reversine is shown in targeting tumor-stromal interfacial interactions using ER+ MCF-7 breast cancer and bone marrow-derived stromal cells. Reversine suppresses MCF-7 tumor growth and bone metastasis in vivo by reducing tumor stromalization including collagen deposition and recruitment of activated stromal cells. This study advocates μTSA as a platform for studying tumor microenvironmental interactions and cancer field effects with applications in drug discovery and development.
    Nature Communications 12/2014; 5. DOI:10.1038/ncomms6662 · 10.74 Impact Factor
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    ABSTRACT: Exposure to psychosocial stress is a risk factor for many diseases, including atherosclerosis. Although incompletely understood, interaction between the psyche and the immune system provides one potential mechanism linking stress and disease inception and progression. Known cross-talk between the brain and immune system includes the hypothalamic-pituitary-adrenal axis, which centrally drives glucocorticoid production in the adrenal cortex, and the sympathetic-adrenal-medullary axis, which controls stress-induced catecholamine release in support of the fight-or-flight reflex. It remains unknown, however, whether chronic stress changes hematopoietic stem cell activity. Here we show that stress increases proliferation of these most primitive hematopoietic progenitors, giving rise to higher levels of disease-promoting inflammatory leukocytes. We found that chronic stress induced monocytosis and neutrophilia in humans. While investigating the source of leukocytosis in mice, we discovered that stress activates upstream hematopoietic stem cells. Under conditions of chronic variable stress in mice, sympathetic nerve fibers released surplus noradrenaline, which signaled bone marrow niche cells to decrease CXCL12 levels through the β3-adrenergic receptor. Consequently, hematopoietic stem cell proliferation was elevated, leading to an increased output of neutrophils and inflammatory monocytes. When atherosclerosis-prone Apoe(-/-) mice were subjected to chronic stress, accelerated hematopoiesis promoted plaque features associated with vulnerable lesions that cause myocardial infarction and stroke in humans.
    Nature Medicine 06/2014; 20(7):754-8. DOI:10.1038/nm.3589 · 28.05 Impact Factor
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    ABSTRACT: Myocarditis is characterized by inflammatory cell infiltration of the heart and subsequent deterioration of cardiac function. Monocytes are the most prominent population of accumulating leucocytes. We investigated whether in vivo administration of nanoparticle-encapsulated siRNA targeting chemokine (C-C motif) receptor 2 (CCR2)-a chemokine receptor crucial for leucocyte migration in humans and mice-reduces inflammation in autoimmune myocarditis.
    European Heart Journal 06/2014; DOI:10.1093/eurheartj/ehu225 · 14.72 Impact Factor
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    ABSTRACT: Pneumonia is a major cause of mortality worldwide and a serious problem in critical care medicine, but the immunophysiological processes that confer either protection or morbidity are not completely understood. We show that in response to lung infection, B1a B cells migrate from the pleural space to the lung parenchyma to secrete polyreactive emergency immunoglobulin M (IgM). The process requires innate response activator (IRA) B cells, a transitional B1a-derived inflammatory subset which controls IgM production via autocrine granulocyte/macrophage colony-stimulating factor (GM-CSF) signaling. The strategic location of these cells, coupled with the capacity to produce GM-CSF-dependent IgM, ensures effective early frontline defense against bacteria invading the lungs. The study describes a previously unrecognized GM-CSF-IgM axis and positions IRA B cells as orchestrators of protective IgM immunity.
    Journal of Experimental Medicine 05/2014; 211(6). DOI:10.1084/jem.20131471 · 13.91 Impact Factor
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    ABSTRACT: Macrophages populate the steady-state myocardium. Previously, all macrophages were thought to arise from monocytes; however, it emerged that in several organs tissue-resident macrophages may self-maintain through local proliferation. To study the contribution of monocytes to cardiac resident macrophages in steady-state, after macrophage depletion in CD11b(DTR/+) mice and in myocardial infarction. Using in vivo fate mapping and flow cytometry, we estimated that during steady-state the heart macrophage population turns over in about one month. To explore the source of cardiac resident macrophages, we joined the circulation of mice using parabiosis. After 6 weeks, we observed blood monocyte chimerism of 35.3±3.4% while heart macrophages showed a much lower chimerism of 2.7±0.5% (p<0.01). Macrophages self renewed locally through proliferation: 2.1±0.3% incorporated BrdU 2 hours after a single injection and 13.7±1.4% heart macrophages stained positive for the cell cycle marker Ki67. The cells likely participate in defense against infection, as we found them to ingest fluorescently labeled bacteria. In ischemic myocardium, we observed that tissue resident macrophages died locally while some also migrated to hematopoietic organs. If the steady-state was perturbed by coronary ligation or diphtheria toxin-induced macrophage depletion in CD11b(DTR/+) mice, blood monocytes replenished heart macrophages. However, in the chronic phase after myocardial infarction, macrophages residing in the infarct were again independent from the blood monocyte pool, returning to the steady-state situation. In this study we show differential contribution of monocytes to heart macrophages during steady-state, after macrophage depletion or in the acute and chronic phase after myocardial infarction. We found that macrophages participate in the immunosurveillance of myocardial tissue. These data correspond with previous studies on tissue-resident macrophages and raise important questions on the fate and function of macrophages during the development of heart failure.
    Circulation Research 05/2014; 115(2). DOI:10.1161/CIRCRESAHA.115.303567 · 11.09 Impact Factor
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    ABSTRACT: Healing after myocardial infarction (MI) involves the biphasic accumulation of inflammatory Ly-6C(high) and reparative Ly-6C(low) monocytes/macrophages (Mo/MΦ). According to one model, Mo/MΦ heterogeneity in the heart originates in the blood and involves the sequential recruitment of distinct monocyte subsets that differentiate to distinct macrophages. Alternatively, heterogeneity may arise in tissue from one circulating subset via local macrophage differentiation and polarization. The orphan nuclear hormone receptor, Nr4a1, is essential to Ly-6C(low) monocyte production but dispensable to Ly-6C(low) macrophage differentiation; dependence on Nr4a1 can thus discriminate between systemic and local origins of macrophage heterogeneity. This study tested the role of Nr4a1 in MI in the context of the two Mo/MΦ accumulation scenarios. We show that Ly-6C(high) monocytes infiltrate the infarcted myocardium and, unlike Ly-6C(low) monocytes, differentiate to cardiac macrophages. In the early, inflammatory phase of acute myocardial ischemic injury, Ly-6C(hig)h monocytes accrue in response to a brief Ccl2 burst. In the second, reparative phase, accumulated Ly-6C(high) monocytes give rise to reparative Ly-6C(low) F4/80high macrophages that proliferate locally. In the absence of Nr4a1, Ly-6C(high) monocytes express heightened levels of Ccr2 on their surface, avidly infiltrate the myocardium, and differentiate to abnormally inflammatory macrophages, which results in defective healing and compromised heart function. Ly-6C(high) monocytes orchestrate both inflammatory and reparative phases during MI and depend on Nr4a1 to limit their influx and inflammatory cytokine expression.
    Circulation Research 03/2014; 114(10). DOI:10.1161/CIRCRESAHA.114.303204 · 11.09 Impact Factor
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    ABSTRACT: Atherosclerotic lesions grow via the accumulation of leukocytes and oxidized lipoproteins in the vessel wall. Leukocytes can attenuate or augment atherosclerosis through the release of cytokines, chemokines, and other mediators. Deciphering how leukocytes develop, oppose and complement each other's function, and shape the course of disease, can illuminate understanding of atherosclerosis. Innate response activator (IRA) B cells are a recently described population of GM-CSF-secreting cells of hitherto unknown function in atherosclerosis. Here we show that IRA B cells arise during atherosclerosis in mice and humans. In response to high cholesterol diet, IRA B cell numbers increase preferentially in secondary lymphoid organs via Myd88-dependent signaling. Mixed chimeric mice lacking B cell-derived GM-CSF develop smaller lesions with fewer macrophages and effector T cells. Mechanistically, IRA B cells promote the expansion of classical dendritic cells, which then generate IFNγ-producing TH1 cells. This IRA B cell-dependent TH1 skewing manifests in an IgG1 to IgG2c isotype switch in the immunoglobulin response against oxidized lipoproteins. GM-CSF-producing IRA B cells alter adaptive immune processes and shift the leukocyte response toward a TH1-associated mileu that aggravates atherosclerosis.
    Circulation 01/2014; 129(16). DOI:10.1161/CIRCULATIONAHA.113.006381 · 14.95 Impact Factor
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    ABSTRACT: The aim of the study was to test wether silencing of the transcription factor Interferon Regulatory Factor 5 (IRF5) in cardiac macrophages improves infarct healing and attenuates post-MI remodeling. In healing wounds, M1➛M2 macrophage phenotype transition supports resolution of inflammation and tissue repair. Persistence of inflammatory M1 macrophages may derail healing and compromise organ functions. The transcription factor IRF5 promotes genes associated with M1 macrophages. Here we used nanoparticle-delivered siRNA to silence the transcription factor IRF5 in macrophages residing in myocardial infarcts (MI) and in surgically induced skin wounds in mice. Infarct macrophages expressed high levels of IRF5 during the early inflammatory wound healing stages (day 4 after coronary ligation) whereas expression of the transcription factor decreased during the resolution of inflammation (day 8). Following in vitro screening, we identified an siRNA sequence that, when delivered by nanoparticles to wound macrophages, efficiently suppressed expression of IRF5 in vivo. Reduction of IRF5 expression, a factor that regulates macrophage polarization, reduced inflammatory M1 macrophage markers, supported resolution of inflammation, accelerated cutaneous and infarct healing and attenuated development of post-MI heart failure after coronary ligation as measured by protease targeted FMT-CT imaging and cardiac MRI (p<0.05 respectively). This work identifies a new therapeutic avenue to augment resolution of inflammation in healing infarcts by macrophage phenotype manipulation. This therapeutic concept may be used to attenuate post-MI remodeling and heart failure.
    Journal of the American College of Cardiology 12/2013; 63(15). DOI:10.1016/j.jacc.2013.11.023 · 15.34 Impact Factor
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    ABSTRACT: During the inflammatory response that drives atherogenesis, macrophages accumulate progressively in the expanding arterial wall. The observation that circulating monocytes give rise to lesional macrophages has reinforced the concept that monocyte infiltration dictates macrophage buildup. Recent work has indicated, however, that macrophage accumulation does not depend on monocyte recruitment in some inflammatory contexts. We therefore revisited the mechanism underlying macrophage accumulation in atherosclerosis. In murine atherosclerotic lesions, we found that macrophages turn over rapidly, after 4 weeks. Replenishment of macrophages in these experimental atheromata depends predominantly on local macrophage proliferation rather than monocyte influx. The microenvironment orchestrates macrophage proliferation through the involvement of scavenger receptor A (SR-A). Our study reveals macrophage proliferation as a key event in atherosclerosis and identifies macrophage self-renewal as a therapeutic target for cardiovascular disease.
    Nature medicine 08/2013; 19(9). DOI:10.1038/nm.3258 · 28.05 Impact Factor
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    ABSTRACT: BACKGROUND: -Macrophages (MΦ) predominate among the inflammatory cells in rejecting allografts. These innate immune cells, in addition to allospecific T cells, can damage cardiomyocytes directly. METHODS AND RESULTS: -We explored if sensitive PET/CT imaging of MΦ-avid nanoparticles detects rejection of heart allografts in mice. In addition, we employed the imaging method to follow the immunomodulatory impact of angiotensin converting enzyme inhibititor therapy (ACEi) on myeloid cells in allografts. Dextran nanoparticles were derivatized with the PET isotope copper-64 and imaged seven days after transplantation. C57/BL6 recipients of BALB/c allografts displayed robust PET signal (standard uptake value allograft, 2.8±0.3; isograft control, 1.7±0.2; p<0.05). Autoradiography and scintillation counting confirmed the in vivo findings. We then imaged the effects of ACEi (5mg/kg Enalapril). ACEi significantly decreased nanoparticle signal (p<0.05). Histology and flow cytometry showed a reduced number of myeloid cells in the graft, blood and lymph nodes, as well as diminished antigen presentation (p<0.05 versus untreated allografts). ACEi also significantly prolonged allograft survival (12 versus 7 days, p<0.0001). CONCLUSIONS: -Nanoparticle MΦ PET-CT detects heart transplant rejection and predicts organ survival by reporting on myeloid cells.
    Circulation Cardiovascular Imaging 06/2013; 6(4). DOI:10.1161/CIRCIMAGING.113.000481 · 6.75 Impact Factor
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    ABSTRACT: Background—Exaggerated and prolonged inflammation after myocardial infarction (MI) accelerates left ventricular remodeling. Inflammatory pathways may present a therapeutic target to prevent post-MI heart failure. However, the appropriate magnitude and timing of interventions are largely unknown, in part because noninvasive monitoring tools are lacking. Here, we used nanoparticle-facilitated silencing of CCR2, the chemokine receptor that governs inflammatory Ly-6Chigh monocyte subset traffic, to reduce infarct inflammation in apolipoprotein E–deficient (apoE−/−) mice after MI. We used dual-target positron emission tomography/magnetic resonance imaging of transglutaminase factor XIII (FXIII) and myeloperoxidase (MPO) activity to monitor how monocyte subset–targeted RNAi altered infarct inflammation and healing. Methods and Results—Flow cytometry, gene expression analysis, and histology revealed reduced monocyte numbers and enhanced resolution of inflammation in infarcted hearts of apoE−/− mice that were treated with nanoparticle-encapsulated siRNA. To follow extracellular matrix cross-linking noninvasively, we developed a fluorine-18–labeled positron emission tomography agent (18F-FXIII). Recruitment of MPO-rich inflammatory leukocytes was imaged with a molecular magnetic resonance imaging sensor of MPO activity (MPO-Gd). Positron emission tomography/magnetic resonance imaging detected anti-inflammatory effects of intravenous nanoparticle-facilitated siRNA therapy (75% decrease of MPO-Gd signal; P<0.05), whereas 18F-FXIII positron emission tomography reflected unimpeded matrix cross-linking in the infarct. Silencing of CCR2 during the first week after MI improved ejection fraction on day 21 after MI from 29% to 35% (P<0.05). Conclusion—CCR2-targeted RNAi reduced recruitment of Ly-6Chigh monocytes, attenuated infarct inflammation, and curbed post-MI left ventricular remodeling.
    Circulation 04/2013; 127(20). DOI:10.1161/CIRCULATIONAHA.112.000116 · 14.95 Impact Factor
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    ABSTRACT: Macrophages frequently infiltrate tumors and can enhance cancer growth, yet the origins of the macrophage response are not well understood. Here we address molecular mechanisms of macrophage production in a conditional mouse model of lung adenocarcinoma. We report that overproduction of the peptide hormone Angiotensin II (AngII) in tumor-bearing mice amplifies self-renewing hematopoietic stem cells (HSCs) and macrophage progenitors. The process occurred in the spleen but not the bone marrow, and was independent of hemodynamic changes. The effects of AngII required direct hormone ligation on HSCs, depended on S1P(1) signaling, and allowed the extramedullary tissue to supply new tumor-associated macrophages throughout cancer progression. Conversely, blocking AngII production prevented cancer-induced HSC and macrophage progenitor amplification and thus restrained the macrophage response at its source. These findings indicate that AngII acts upstream of a potent macrophage amplification program and that tumors can remotely exploit the hormone's pathway to stimulate cancer-promoting immunity.
    Immunity 01/2013; DOI:10.1016/j.immuni.2012.10.015 · 19.75 Impact Factor
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    ABSTRACT: Rationale: Myeloid cell content in atherosclerotic plaques associates with rupture and thrombosis. Thus, imaging of lesional monocytes and macrophages could serve as a biomarker of disease progression and therapeutic intervention. Objective: To noninvasively assess plaque inflammation with dextran nanoparticle (DNP)-facilitated hybrid positron emission tomography/magnetic resonance imaging (PET/MRI). Methods and Results: Using clinically approved building blocks, we systematically developed 13-nm polymeric nanoparticles consisting of cross-linked short chain dextrans, which were modified with desferoxamine for zirconium-89 radiolabeling ([superscript 89]Zr-DNP) and a near-infrared fluorochrome (VT680) for microscopic and cellular validation. Flow cytometry of cells isolated from excised aortas showed DNP uptake predominantly in monocytes and macrophages (76.7%) and lower signal originating from other leukocytes, such as neutrophils and lymphocytes (11.8% and 0.7%, P<0.05 versus monocytes and macrophages). DNP colocalized with the myeloid cell marker CD11b on immunohistochemistry. PET/MRI revealed high uptake of [superscript 89]Zr-DNP in the aortic root of apolipoprotein E knock out (ApoE[superscript −/−]) mice (standard uptake value, ApoE[superscript −/−] mice versus wild-type controls, 1.9±0.28 versus 1.3±0.03; P<0.05), corroborated by ex vivo scintillation counting and autoradiography. Therapeutic silencing of the monocyte-recruiting receptor C-C chemokine receptor type 2 with short-interfering RNA decreased [superscript 89]Zr-DNP plaque signal (P<0.05) and inflammatory gene expression (P<0.05). Conclusions: Hybrid PET/MRI with a 13-nm DNP enables noninvasive assessment of inflammation in experimental atherosclerotic plaques and reports on therapeutic efficacy of anti-inflammatory therapy.
    Circulation Research 01/2013; 112(5). DOI:10.1161/CIRCRESAHA.111.300576 · 11.09 Impact Factor
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    ABSTRACT: The treatment of diseased vasculature remains challenging, in part because of the difficulty in implanting drug-eluting devices without subjecting vessels to damaging mechanical forces. Implanting materials using adhesive forces could overcome this challenge, but materials have previously not been shown to durably adhere to intact endothelium under blood flow. Marine mussels secrete strong underwater adhesives that have been mimicked in synthetic systems. Here we develop a drug-eluting bioadhesive gel that can be locally and durably glued onto the inside surface of blood vessels. In a mouse model of atherosclerosis, inflamed plaques treated with steroid-eluting adhesive gels had reduced macrophage content and developed protective fibrous caps covering the plaque core. Treatment also lowered plasma cytokine levels and biomarkers of inflammation in the plaque. The drug-eluting devices developed here provide a general strategy for implanting therapeutics in the vasculature using adhesive forces and could potentially be used to stabilize rupture-prone plaques.
    Proceedings of the National Academy of Sciences 12/2012; 109(52). DOI:10.1073/pnas.1217972110 · 9.81 Impact Factor

Publication Stats

2k Citations
673.18 Total Impact Points

Institutions

  • 2011–2015
    • Harvard Medical School
      • Department of Medicine
      Boston, Massachusetts, United States
  • 2010–2015
    • Massachusetts General Hospital
      • • Center for Systems Biology
      • • Center for Molecular Imaging Research
      Boston, Massachusetts, United States
  • 2009–2014
    • Harvard University
      Cambridge, Massachusetts, United States
  • 2012
    • CSL Behring
      KPD, Pennsylvania, United States