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Schaer DJ, Schulthess-Lutz N, Baselgia L, Hansen K, Buzzi RM, Humar R, Dürst E, Vallelian F. Hemorrhage-activated NRF2 in tumor-associated macrophages drives cancer growth, invasion, and immunotherapy resistance. J Clin Invest 2023; 134:e174528. [PMID: 38060331 PMCID: PMC10849758 DOI: 10.1172/jci174528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/28/2023] [Indexed: 02/02/2024] Open
Abstract
Microscopic hemorrhage is a common aspect of cancers, yet its potential role as an independent factor influencing both cancer progression and therapeutic response is largely ignored. Recognizing the essential function of macrophages in red blood cell disposal, we explored a pathway that connects intratumoral hemorrhage with the formation of cancer-promoting tumor-associated macrophages (TAMs). Using spatial transcriptomics, we found that NRF2-activated myeloid cells possessing characteristics of procancerous TAMs tend to cluster in perinecrotic hemorrhagic tumor regions. These cells resembled antiinflammatory erythrophagocytic macrophages. We identified heme, a red blood cell metabolite, as a pivotal microenvironmental factor steering macrophages toward protumorigenic activities. Single-cell RNA-Seq and functional assays of TAMs in 3D cell culture spheroids revealed how elevated intracellular heme signals via the transcription factor NRF2 to induce cancer-promoting TAMs. These TAMs stabilized epithelial-mesenchymal transition, enhancing cancer invasiveness and metastatic potential. Additionally, NRF2-activated macrophages exhibited resistance to reprogramming by IFN-γ and anti-CD40 antibodies, reducing their tumoricidal capacity. Furthermore, MC38 colon adenocarcinoma-bearing mice with NRF2 constitutively activated in leukocytes were resistant to anti-CD40 immunotherapy. Overall, our findings emphasize hemorrhage-activated NRF2 in TAMs as a driver of cancer progression, suggesting that targeting this pathway could offer new strategies to enhance cancer immunity and overcome therapy resistance.
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2
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Galea I, Bandyopadhyay S, Bulters D, Humar R, Hugelshofer M, Schaer DJ. Haptoglobin Treatment for Aneurysmal Subarachnoid Hemorrhage: Review and Expert Consensus on Clinical Translation. Stroke 2023; 54:1930-1942. [PMID: 37232189 PMCID: PMC10289236 DOI: 10.1161/strokeaha.123.040205] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/31/2023] [Accepted: 04/12/2023] [Indexed: 05/27/2023]
Abstract
Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating form of stroke frequently affecting young to middle-aged adults, with an unmet need to improve outcome. This special report focusses on the development of intrathecal haptoglobin supplementation as a treatment by reviewing current knowledge and progress, arriving at a Delphi-based global consensus regarding the pathophysiological role of extracellular hemoglobin and research priorities for clinical translation of hemoglobin-scavenging therapeutics. After aneurysmal subarachnoid hemorrhage, erythrocyte lysis generates cell-free hemoglobin in the cerebrospinal fluid, which is a strong determinant of secondary brain injury and long-term clinical outcome. Haptoglobin is the body's first-line defense against cell-free hemoglobin by binding it irreversibly, preventing translocation of hemoglobin into the brain parenchyma and nitric oxide-sensitive functional compartments of cerebral arteries. In mouse and sheep models, intraventricular administration of haptoglobin reversed hemoglobin-induced clinical, histological, and biochemical features of human aneurysmal subarachnoid hemorrhage. Clinical translation of this strategy imposes unique challenges set by the novel mode of action and the anticipated need for intrathecal drug administration, necessitating early input from stakeholders. Practising clinicians (n=72) and scientific experts (n=28) from 5 continents participated in the Delphi study. Inflammation, microvascular spasm, initial intracranial pressure increase, and disruption of nitric oxide signaling were deemed the most important pathophysiological pathways determining outcome. Cell-free hemoglobin was thought to play an important role mostly in pathways related to iron toxicity, oxidative stress, nitric oxide, and inflammation. While useful, there was consensus that further preclinical work was not a priority, with most believing the field was ready for an early phase trial. The highest research priorities were related to confirming haptoglobin's anticipated safety, individualized versus standard dosing, timing of treatment, pharmacokinetics, pharmacodynamics, and outcome measure selection. These results highlight the need for early phase trials of intracranial haptoglobin for aneurysmal subarachnoid hemorrhage, and the value of early input from clinical disciplines on a global scale during the early stages of clinical translation.
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Affiliation(s)
- Ian Galea
- Department of Clinical Neurosciences, Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Hampshire, United Kingdom (I.G., S.B., D.B.)
- Wessex Neurological Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom (I.G., S.B., D.B.)
| | - Soham Bandyopadhyay
- Department of Clinical Neurosciences, Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Hampshire, United Kingdom (I.G., S.B., D.B.)
- Wessex Neurological Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom (I.G., S.B., D.B.)
| | - Diederik Bulters
- Department of Clinical Neurosciences, Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Hampshire, United Kingdom (I.G., S.B., D.B.)
- Wessex Neurological Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom (I.G., S.B., D.B.)
| | - Rok Humar
- Division of Internal Medicine (R.H., D.J.S.), Universitätsspital and University of Zurich, Switzerland
| | - Michael Hugelshofer
- Department of Neurosurgery, Clinical Neuroscience Center (M.H.), Universitätsspital and University of Zurich, Switzerland
| | - Dominik J. Schaer
- Division of Internal Medicine (R.H., D.J.S.), Universitätsspital and University of Zurich, Switzerland
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3
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Pfefferlé M, Dubach IL, Buzzi RM, Dürst E, Schulthess-Lutz N, Baselgia L, Hansen K, Imhof L, Koernig S, Le Roy D, Roger T, Humar R, Schaer DJ, Vallelian F. Antibody-induced erythrophagocyte reprogramming of Kupffer cells prevents anti-CD40 cancer immunotherapy-associated liver toxicity. J Immunother Cancer 2023; 11:jitc-2022-005718. [PMID: 36593065 PMCID: PMC9809320 DOI: 10.1136/jitc-2022-005718] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2022] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Agonistic anti-CD40 monoclonal antibodies (mAbs) have emerged as promising immunotherapeutic compounds with impressive antitumor effects in mouse models. However, preclinical and clinical studies faced dose-limiting toxicities mediated by necroinflammatory liver disease. An effective prophylactic treatment for liver immune-related adverse events that does not suppress specific antitumor immunity remains to be found. METHODS We used different mouse models and time-resolved single-cell RNA-sequencing to characterize the pathogenesis of anti-CD40 mAb induced liver toxicity. Subsequently, we developed an antibody-based treatment protocol to selectively target red blood cells (RBCs) for erythrophagocytosis in the liver, inducing an anti-inflammatory liver macrophage reprogramming. RESULTS We discovered that CD40 signaling in Clec4f+ Kupffer cells is the non-redundant trigger of anti-CD40 mAb-induced liver toxicity. Taking advantage of the highly specific functionality of liver macrophages to clear antibody-tagged RBCs from the blood, we hypothesized that controlled erythrophagocytosis and the linked anti-inflammatory signaling by the endogenous metabolite heme could be exploited to reprogram liver macrophages selectively. Repeated low-dose administration of a recombinant murine Ter119 antibody directed RBCs for selective phagocytosis in the liver and skewed the phenotype of liver macrophages into a Hmoxhigh/Marcohigh/MHCIIlow anti-inflammatory phenotype. This unique mode of action prevented necroinflammatory liver disease following high-dose administration of anti-CD40 mAbs. In contrast, extrahepatic inflammation, antigen-specific immunity, and antitumor activity remained unaffected in Ter119 treated animals. CONCLUSIONS Our study offers a targeted approach to uncouple CD40-augmented antitumor immunity in peripheral tissues from harmful inflammatoxicity in the liver.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Sandra Koernig
- CSL Ltd., Research, Bio21 Institute, Parkville, Victoria, Australia
| | | | | | - Rok Humar
- University of Zurich, Zurich, Switzerland
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4
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Humar R, Schaer DJ, Vallelian F. Erythrophagocytes in hemolytic anemia, wound healing, and cancer. Trends Mol Med 2022; 28:906-915. [PMID: 36096988 DOI: 10.1016/j.molmed.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/11/2022] [Accepted: 08/11/2022] [Indexed: 11/18/2022]
Abstract
Hemolysis is a ubiquitous pathology defined as premature red blood cell destruction within the circulation or local tissues. One of the most archetypal functions of macrophages is phagocytosis of damaged or extravasated red blood cells, preventing the extracellular release of toxic hemoglobin and heme. Upon erythrophagocytosis, spiking intracellular heme concentrations drive macrophage transformation into erythrophagocytes, leveraging antioxidative and iron recycling capacities to defend against hemolytic stress. This unique phenotype transformation is coordinated by a regulatory network comprising the transcription factors BACH1, SPI-C, NRF2, and ATF1. Erythrophagocytes negatively regulate inflammation and immunity and may modulate disease-specific outcomes in hemolytic anemia, wound healing, atherosclerosis, and cancer. In this opinion article, we outline the known and presumed functions of erythrophagocytes and their implications for therapeutic innovation and research.
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Affiliation(s)
- Rok Humar
- Department of Internal Medicine, University Hospital and University of Zurich, Zurich, Switzerland
| | - Dominik J Schaer
- Department of Internal Medicine, University Hospital and University of Zurich, Zurich, Switzerland
| | - Florence Vallelian
- Department of Internal Medicine, University Hospital and University of Zurich, Zurich, Switzerland.
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5
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Vallelian F, Buzzi RM, Pfefferlé M, Yalamanoglu A, Dubach IL, Wassmer A, Gentinetta T, Hansen K, Humar R, Schulthess N, Schaer CA, Schaer DJ. Heme-stress activated NRF2 skews fate trajectories of bone marrow cells from dendritic cells towards red pulp-like macrophages in hemolytic anemia. Cell Death Differ 2022; 29:1450-1465. [PMID: 35031770 PMCID: PMC9345992 DOI: 10.1038/s41418-022-00932-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 12/15/2021] [Accepted: 12/29/2021] [Indexed: 12/28/2022] Open
Abstract
Heme is an erythrocyte-derived toxin that drives disease progression in hemolytic anemias, such as sickle cell disease. During hemolysis, specialized bone marrow-derived macrophages with a high heme-metabolism capacity orchestrate disease adaptation by removing damaged erythrocytes and heme-protein complexes from the blood and supporting iron recycling for erythropoiesis. Since chronic heme-stress is noxious for macrophages, erythrophagocytes in the spleen are continuously replenished from bone marrow-derived progenitors. Here, we hypothesized that adaptation to heme stress progressively shifts differentiation trajectories of bone marrow progenitors to expand the capacity of heme-handling monocyte-derived macrophages at the expense of the homeostatic generation of dendritic cells, which emerge from shared myeloid precursors. This heme-induced redirection of differentiation trajectories may contribute to hemolysis-induced secondary immunodeficiency. We performed single-cell RNA-sequencing with directional RNA velocity analysis of GM-CSF-supplemented mouse bone marrow cultures to assess myeloid differentiation under heme stress. We found that heme-activated NRF2 signaling shifted the differentiation of bone marrow cells towards antioxidant, iron-recycling macrophages, suppressing the generation of dendritic cells in heme-exposed bone marrow cultures. Heme eliminated the capacity of GM-CSF-supplemented bone marrow cultures to activate antigen-specific CD4 T cells. The generation of functionally competent dendritic cells was restored by NRF2 loss. The heme-induced phenotype of macrophage expansion with concurrent dendritic cell depletion was reproduced in hemolytic mice with sickle cell disease and spherocytosis and associated with reduced dendritic cell functions in the spleen. Our data provide a novel mechanistic underpinning of hemolytic stress as a driver of hyposplenism-related secondary immunodeficiency. ![]()
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Affiliation(s)
- Florence Vallelian
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland.
| | - Raphael M Buzzi
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Marc Pfefferlé
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Ayla Yalamanoglu
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Irina L Dubach
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | | | | | - Kerstin Hansen
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Rok Humar
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Nadja Schulthess
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | | | - Dominik J Schaer
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
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Akeret K, Buzzi RM, Saxenhofer M, Bieri K, Chiavi D, Thomson BR, Grüttner-Durmaz M, Schwendinger N, Humar R, Regli L, van Doormaal TPC, Held U, Keller E, Hugelshofer M, Schaer DJ. The HeMoVal study protocol: a prospective international multicenter cohort study to validate cerebrospinal fluid hemoglobin as a monitoring biomarker for aneurysmal subarachnoid hemorrhage related secondary brain injury. BMC Neurol 2022; 22:267. [PMID: 35850705 PMCID: PMC9290286 DOI: 10.1186/s12883-022-02789-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 07/07/2022] [Indexed: 11/17/2022] Open
Abstract
Introduction Preclinical studies provided a strong rationale for a pathophysiological link between cell-free hemoglobin in the cerebrospinal fluid (CSF-Hb) and secondary brain injury after subarachnoid hemorrhage (SAH-SBI). In a single-center prospective observational clinical study, external ventricular drain (EVD) based CSF-Hb proved to be a promising biomarker to monitor for SAH-SBI. The primary objective of the HeMoVal study is to prospectively validate the association between EVD based CSF-Hb and SAH-SBI during the first 14 days post-SAH. Secondary objectives include the assessment of the discrimination ability of EVD based CSF-Hb for SAH-SBI and the definition of a clinically relevant range of EVD based CSF-Hb toxicity. In addition, lumbar drain (LD) based CSF-Hb will be assessed for its association with and discrimination ability for SAH-SBI. Methods HeMoVal is a prospective international multicenter observational cohort study. Adult patients admitted with aneurysmal subarachnoid hemorrhage (aSAH) are eligible. While all patients with aSAH are included, we target a sample size of 250 patients with EVD within the first 14 day after aSAH. Epidemiologic and disease-specific baseline measures are assessed at the time of study inclusion. In patients with EVD or LD, each day during the first 14 days post-SAH, 2 ml of CSF will be sampled in the morning, followed by assessment of the patients for SAH-SBI, co-interventions, and complications in the afternoon. After 3 months, a clinical follow-up will be performed. For statistical analysis, the cohort will be stratified into an EVD, LD and full cohort. The primary analysis will quantify the strength of association between EVD based CSF-Hb and SAH-SBI in the EVD cohort based on a generalized additive model. Secondary analyses include the strength of association between LD based CSF-Hb and SAH-SBI in the LD cohort based on a generalized additive model, as well as the discrimination ability of CSF-Hb for SAH-SBI based on receiver operating characteristic (ROC) analyses. Discussion We hypothesize that this study will validate the value of CSF-Hb as a biomarker to monitor for SAH-SBI. In addition, the results of this study will provide the potential base to define an intervention threshold for future studies targeting CSF-Hb toxicity after aSAH. Study registration ClinicalTrials.gov Identifier NCT04998370. Date of registration: August 10, 2021.
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Affiliation(s)
- Kevin Akeret
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich, Zurich, Switzerland
| | - Raphael M Buzzi
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich, Switzerland
| | | | | | - Deborah Chiavi
- Department of Biostatistics at Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland
| | - Bart R Thomson
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich, Zurich, Switzerland
| | - Manuela Grüttner-Durmaz
- Clinical Trials Center - Research Ward (CTC-RW), University Hospital Zurich, Zurich, Switzerland
| | - Nina Schwendinger
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich, Zurich, Switzerland
| | - Rok Humar
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich, Switzerland
| | - Luca Regli
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich, Zurich, Switzerland
| | - Tristan P C van Doormaal
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich, Zurich, Switzerland.,Department of Neurology and Neurosurgery, University Medical Center, Utrecht, The Netherlands
| | - Ulrike Held
- Department of Biostatistics at Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland
| | - Emanuela Keller
- Neurointensive Care Unit, Department of Neurosurgery and Institute of Intensive Care Medicine, Universitätsspital and University of Zurich, Zurich, Switzerland
| | - Michael Hugelshofer
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich, Zurich, Switzerland.
| | - Dominik J Schaer
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich, Switzerland
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7
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Akeret K, Buzzi RM, Schaer CA, Thomson BR, Vallelian F, Wang S, Willms J, Sebök M, Held U, Deuel JW, Humar R, Regli L, Keller E, Hugelshofer M, Schaer DJ. Cerebrospinal fluid hemoglobin drives subarachnoid hemorrhage-related secondary brain injury. J Cereb Blood Flow Metab 2021; 41:3000-3015. [PMID: 34102922 PMCID: PMC8545037 DOI: 10.1177/0271678x211020629] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Secondary brain injury after aneurysmal subarachnoid hemorrhage (SAH-SBI) contributes to poor outcomes in patients after rupture of an intracranial aneurysm. The lack of diagnostic biomarkers and novel drug targets represent an unmet need. The aim of this study was to investigate the clinical and pathophysiological association between cerebrospinal fluid hemoglobin (CSF-Hb) and SAH-SBI. In a cohort of 47 patients, we collected daily CSF-samples within 14 days after aneurysm rupture. There was very strong evidence for a positive association between spectrophotometrically determined CSF-Hb and SAH-SBI. The accuracy of CSF-Hb to monitor for SAH-SBI markedly exceeded that of established methods (AUC: 0.89 [0.85-0.92]). Temporal proteome analysis revealed erythrolysis accompanied by an adaptive macrophage response as the two dominant biological processes in the CSF-space after aneurysm rupture. Ex-vivo experiments on the vasoconstrictive and oxidative potential of Hb revealed critical inflection points overlapping CSF-Hb thresholds in patients with SAH-SBI. Selective depletion and in-solution neutralization by haptoglobin or hemopexin efficiently attenuated the vasoconstrictive and lipid peroxidation activities of CSF-Hb. Collectively, the clinical association between high CSF-Hb levels and SAH-SBI, the underlying pathophysiological rationale, and the favorable effects of haptoglobin and hemopexin in ex-vivo experiments position CSF-Hb as a highly attractive biomarker and potential drug target.
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Affiliation(s)
- Kevin Akeret
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich; Zurich, Switzerland
| | - Raphael M Buzzi
- Division of Internal Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Christian A Schaer
- Department of Anesthesiology, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Bart R Thomson
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich; Zurich, Switzerland
| | - Florence Vallelian
- Division of Internal Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Sophie Wang
- Neurointensive Care Unit, Department of Neurosurgery and Institute of Intensive Care Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Jan Willms
- Neurointensive Care Unit, Department of Neurosurgery and Institute of Intensive Care Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Martina Sebök
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich; Zurich, Switzerland
| | - Ulrike Held
- Epidemiology, Biostatistics and Prevention Institute, Department of Biostatistics, University of Zurich; Zurich, Switzerland
| | - Jeremy W Deuel
- Division of Internal Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Rok Humar
- Division of Internal Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Luca Regli
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich; Zurich, Switzerland
| | - Emanuela Keller
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich; Zurich, Switzerland.,Neurointensive Care Unit, Department of Neurosurgery and Institute of Intensive Care Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
| | - Michael Hugelshofer
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich; Zurich, Switzerland
| | - Dominik J Schaer
- Division of Internal Medicine, Universitätsspital and University of Zurich; Zurich, Switzerland
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Buzzi RM, Owczarek CM, Akeret K, Tester A, Pereira N, Butcher R, Brügger-Verdon V, Hardy MP, Illi M, Wassmer A, Vallelian F, Humar R, Hugelshofer M, Buehler PW, Gentinetta T, Schaer DJ. Modular Platform for the Development of Recombinant Hemoglobin Scavenger Biotherapeutics. Mol Pharm 2021; 18:3158-3170. [PMID: 34292741 DOI: 10.1021/acs.molpharmaceut.1c00433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cell-free hemoglobin (Hb) is a driver of disease progression in conditions with intravascular or localized hemolysis. Genetic and acquired anemias or emergency medical conditions such as aneurysmal subarachnoid hemorrhage involve tissue Hb exposure. Haptoglobin (Hp) captures Hb in an irreversible protein complex and prevents its pathophysiological contributions to vascular nitric oxide depletion and tissue oxidation. Preclinical proof-of-concept studies suggest that human plasma-derived Hp is a promising therapeutic candidate for several Hb-driven diseases. Optimizing the efficacy and safety of Hb-targeting biotherapeutics may require structural and functional modifications for specific indications. Improved Hp variants could be designed to achieve the desired tissue distribution, metabolism, and elimination to target hemolytic disease states effectively. However, it is critical to ensure that these modifications maintain the function of Hp. Using transient mammalian gene expression of Hp combined with co-transfection of the pro-haptoglobin processing protease C1r-LP, we established a platform for generating recombinant Hp-variants. We designed an Hpβ-scaffold, which was expressed in this system at high levels as a monomeric unit (mini-Hp) while maintaining the key protective functions of Hp. We then used this Hpβ-scaffold as the basis to develop an initial proof-of-concept Hp fusion protein using human serum albumin as the fusion partner. Next, a hemopexin-Hp fusion protein with bispecific heme and Hb detoxification capacity was generated. Further, we developed a Hb scavenger devoid of CD163 scavenger receptor binding. The functions of these proteins were then characterized for Hb and heme-binding, binding of the Hp-Hb complexes with the clearance receptor CD163, antioxidant properties, and vascular nitric oxide sparing capacity. Our platform is designed to support the generation of innovative Hb scavenger biotherapeutics with novel modes of action and potentially improved formulation characteristics, function, and pharmacokinetics.
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Affiliation(s)
- Raphael M Buzzi
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich 8091, Switzerland
| | | | - Kevin Akeret
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich, Zurich 8091, Switzerland
| | - Andrea Tester
- CSL Limited, Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Natasha Pereira
- CSL Limited, Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Rebecca Butcher
- CSL Limited, Bio21 Institute, Parkville, Victoria 3010, Australia
| | | | - Matthew P Hardy
- CSL Limited, Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Marlies Illi
- Research and Development, CSL Behring AG, Bern 3014, Switzerland
| | - Andreas Wassmer
- Research and Development, CSL Behring AG, Bern 3014, Switzerland
| | - Florence Vallelian
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich 8091, Switzerland
| | - Rok Humar
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich 8091, Switzerland
| | - Michael Hugelshofer
- Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital und University of Zurich, Zurich 8091, Switzerland
| | - Paul W Buehler
- Department of Pathology, The University of Maryland School of Medicine, Baltimore, Maryland 21201, United States.,The Center for Blood Oxygen Transport and Hemostasis, Department of Pediatrics, The University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | | | - Dominik J Schaer
- Division of Internal Medicine, Universitätsspital and University of Zurich, Zurich 8091, Switzerland
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9
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Pfefferlé M, Ingoglia G, Schaer CA, Hansen K, Schulthess N, Humar R, Schaer DJ, Vallelian F. Acute Hemolysis and Heme Suppress Anti-CD40 Antibody-Induced Necro-Inflammatory Liver Disease. Front Immunol 2021; 12:680855. [PMID: 34054870 PMCID: PMC8149790 DOI: 10.3389/fimmu.2021.680855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 04/22/2021] [Indexed: 12/21/2022] Open
Abstract
Clearance of red blood cells and hemoproteins is a key metabolic function of macrophages during hemolytic disorders and following tissue injury. Through this archetypical phagocytic function, heme is detoxified and iron is recycled to support erythropoiesis. Reciprocal interaction of heme metabolism and inflammatory macrophage functions may modify disease outcomes in a broad range of clinical conditions. We hypothesized that acute hemolysis and heme induce acute anti-inflammatory signals in liver macrophages. Using a macrophage-driven model of sterile liver inflammation, we showed that phenylhydrazine (PHZ)-mediated acute erythrophagocytosis blocked the anti-CD40 antibody-induced pathway of macrophage activation. This process attenuated the inflammatory cytokine release syndrome and necrotizing hepatitis induced by anti-CD40 antibody treatment of mice. We further established that administration of heme-albumin complexes specifically delivered heme to liver macrophages and replicated the anti-inflammatory effect of hemolysis. The anti-inflammatory heme-signal was induced in macrophages by an increased intracellular concentration of the porphyrin independently of iron. Overall, our work suggests that induction of heme-signaling strongly suppresses inflammatory macrophage function, providing protection against sterile liver inflammation.
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Affiliation(s)
- Marc Pfefferlé
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Giada Ingoglia
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | | | - Kerstin Hansen
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Nadja Schulthess
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Rok Humar
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Dominik J Schaer
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Florence Vallelian
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
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10
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Yalamanoglu A, Dubach IL, Schulthess N, Ingoglia G, Swindle DC, Humar R, Schaer DJ, Buehler PW, Irwin DC, Vallelian F. Agonistic Anti-CD40 Antibody Triggers an Acute Liver Crisis With Systemic Inflammation in Humanized Sickle Cell Disease Mice. Front Immunol 2021; 12:627944. [PMID: 33763072 PMCID: PMC7982888 DOI: 10.3389/fimmu.2021.627944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/11/2021] [Indexed: 11/30/2022] Open
Abstract
Sickle cell disease (SCD) is an inherited hemolytic disorder, defined by a point mutation in the β-globin gene. Stress conditions such as infection, inflammation, dehydration, and hypoxia trigger erythrocyte sickling. Sickled red blood cells (RBCs) hemolyze more rapidly, show impaired deformability, and increased adhesive properties to the endothelium. In a proinflammatory, pro-coagulative environment with preexisting endothelial dysfunction, sickled RBCs promote vascular occlusion. Hepatobiliary involvement related to the sickling process, such as an acute sickle hepatic crisis, is observed in about 10% of acute sickle cell crisis incidents. In mice, ligation of CD40 with an agonistic antibody leads to a macrophage activation in the liver, triggering a sequence of systemic inflammation, endothelial cell activation, thrombosis, and focal ischemia. We found that anti-CD40 antibody injection in sickle cell mice induces a systemic inflammatory and hemodynamic response with accelerated hemolysis, extensive vaso-occlusion, and large ischemic infarctions in the liver mimicking an acute hepatic crisis. Administration of the tumor necrosis factor-α (TNF-α) blocker, etanercept, and the heme scavenger protein, hemopexin attenuated end-organ damage. These data collectively suggest that anti-CD40 administration offers a novel acute liver crisis model in humanized sickle mice, allowing for evaluation of therapeutic proof-of-concept.
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Affiliation(s)
- Ayla Yalamanoglu
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Irina L Dubach
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Nadja Schulthess
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Giada Ingoglia
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Delaney C Swindle
- Cardiovascular and Pulmonary Research Laboratory, Department of Medicine, University of Colorado Denver, Aurora, CO, United States
| | - Rok Humar
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Dominik J Schaer
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
| | - Paul W Buehler
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States.,Center for Blood Oxygen Transport and Hemostasis, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - David C Irwin
- Cardiovascular and Pulmonary Research Laboratory, Department of Medicine, University of Colorado Denver, Aurora, CO, United States
| | - Florence Vallelian
- Division of Internal Medicine, University of Zurich, Zurich, Switzerland
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11
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Pfefferlé M, Ingoglia G, Schaer CA, Yalamanoglu A, Buzzi R, Dubach IL, Tan G, López-Cano EY, Schulthess N, Hansen K, Humar R, Schaer DJ, Vallelian F. Hemolysis transforms liver macrophages into antiinflammatory erythrophagocytes. J Clin Invest 2021; 130:5576-5590. [PMID: 32663195 DOI: 10.1172/jci137282] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022] Open
Abstract
During hemolysis, macrophages in the liver phagocytose damaged erythrocytes to prevent the toxic effects of cell-free hemoglobin and heme. It remains unclear how this homeostatic process modulates phagocyte functions in inflammatory diseases. Using a genetic mouse model of spherocytosis and single-cell RNA sequencing, we found that erythrophagocytosis skewed liver macrophages into an antiinflammatory phenotype that we defined as MarcohiHmoxhiMHC class IIlo erythrophagocytes. This phenotype transformation profoundly mitigated disease expression in a model of an anti-CD40-induced hyperinflammatory syndrome with necrotic hepatitis and in a nonalcoholic steatohepatitis model, representing 2 macrophage-driven sterile inflammatory diseases. We reproduced the antiinflammatory erythrophagocyte transformation in vitro by heme exposure of mouse and human macrophages, yielding a distinctive transcriptional signature that segregated heme-polarized from M1- and M2-polarized cells. Mapping transposase-accessible chromatin in single cells by sequencing defined the transcription factor NFE2L2/NRF2 as a critical driver of erythrophagocytes, and Nfe2l2/Nrf2 deficiency restored heme-suppressed inflammation. Our findings point to a pathway that regulates macrophage functions to link erythrocyte homeostasis with innate immunity.
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Affiliation(s)
| | | | | | | | | | | | - Ge Tan
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Emilio Y López-Cano
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
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12
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Hugelshofer M, Buzzi RM, Schaer CA, Richter H, Akeret K, Anagnostakou V, Mahmoudi L, Vaccani R, Vallelian F, Deuel JW, Kronen PW, Kulcsar Z, Regli L, Baek JH, Pires IS, Palmer AF, Dennler M, Humar R, Buehler PW, Kircher PR, Keller E, Schaer DJ. Haptoglobin administration into the subarachnoid space prevents hemoglobin-induced cerebral vasospasm. J Clin Invest 2020; 129:5219-5235. [PMID: 31454333 DOI: 10.1172/jci130630] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/20/2019] [Indexed: 12/13/2022] Open
Abstract
Delayed ischemic neurological deficit (DIND) is a major driver of adverse outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH), defining an unmet need for therapeutic development. Cell-free hemoglobin that is released from erythrocytes into the cerebrospinal fluid (CSF) is suggested to cause vasoconstriction and neuronal toxicity, and correlates with the occurrence of DIND. Cell-free hemoglobin in the CSF of patients with aSAH disrupted dilatory NO signaling ex vivo in cerebral arteries, which shifted vascular tone balance from dilation to constriction. We found that selective removal of hemoglobin from patient CSF with a haptoglobin-affinity column or its sequestration in a soluble hemoglobin-haptoglobin complex was sufficient to restore physiological vascular responses. In a sheep model, administration of haptoglobin into the CSF inhibited hemoglobin-induced cerebral vasospasm and preserved vascular NO signaling. We identified 2 pathways of hemoglobin delocalization from CSF into the brain parenchyma and into the NO-sensitive compartment of small cerebral arteries. Both pathways were critical for hemoglobin toxicity and were interrupted by the large hemoglobin-haptoglobin complex that inhibited spatial requirements for hemoglobin reactions with NO in tissues. Collectively, our data show that compartmentalization of hemoglobin by haptoglobin provides a novel framework for innovation aimed at reducing hemoglobin-driven neurological damage after subarachnoid bleeding.
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Affiliation(s)
- Michael Hugelshofer
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
| | - Raphael M Buzzi
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
| | - Christian A Schaer
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
| | - Henning Richter
- Clinic for Diagnostic Imaging, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Kevin Akeret
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
| | - Vania Anagnostakou
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
| | - Leila Mahmoudi
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland.,Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Raphael Vaccani
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
| | - Florence Vallelian
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
| | - Jeremy W Deuel
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
| | - Peter W Kronen
- Veterinary Anaesthesia Services - International, Winterthur, Switzerland.,Center for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland
| | - Zsolt Kulcsar
- Department of Neuroradiology, Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
| | - Luca Regli
- Department of Neurosurgery, Clinical Neuroscience Center, University Hospital and University of Zurich, Zurich, Switzerland
| | - Jin Hyen Baek
- Center of Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Ivan S Pires
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Andre F Palmer
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Matthias Dennler
- Clinic for Diagnostic Imaging, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Rok Humar
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
| | - Paul W Buehler
- Center of Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Patrick R Kircher
- Clinic for Diagnostic Imaging, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Emanuela Keller
- Neurointensive Care Unit, University Hospital of Zurich, Zurich, Switzerland
| | - Dominik J Schaer
- Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
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13
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Buehler PW, Humar R, Schaer DJ. Haptoglobin Therapeutics and Compartmentalization of Cell-Free Hemoglobin Toxicity. Trends Mol Med 2020; 26:683-697. [PMID: 32589936 DOI: 10.1016/j.molmed.2020.02.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023]
Abstract
Hemolysis and accumulation of cell-free hemoglobin (Hb) in the circulation or in confined tissue compartments such as the subarachnoid space is an important driver of disease. Haptoglobin is the Hb binding and clearance protein in human plasma and an efficient antagonist of Hb toxicity resulting from physiological red blood cell turnover. However, endogenous concentrations of haptoglobin are insufficient to provide protection against Hb-driven disease processes in conditions such as sickle cell anemia, sepsis, transfusion reactions, medical-device associated hemolysis, or after a subarachnoid hemorrhage. As a result, there is increasing interest in developing haptoglobin therapeutics to target 'toxic' cell-free Hb exposures. Here, we discuss key concepts of Hb toxicity and provide a perspective on the use of haptoglobin as a therapeutic protein.
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Affiliation(s)
- Paul W Buehler
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA; Center for Blood Oxygen Transport and Hemostasis, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Rok Humar
- Division of Internal Medicine, University Hospital, Zurich, Switzerland
| | - Dominik J Schaer
- Division of Internal Medicine, University Hospital, Zurich, Switzerland.
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14
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Hugelshofer M, Deuel J, Buzzi R, Humar R, Schaer D, Schaer C. Determining the Optimal Normalization Factor of Different Target Arteries for ex vivo Vascular Function Experiments: A New Standardized Procedure. J Vasc Res 2020; 57:106-112. [DOI: 10.1159/000505729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 01/03/2020] [Indexed: 11/19/2022] Open
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15
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Vallelian F, Schaer CA, Deuel JW, Ingoglia G, Humar R, Buehler PW, Schaer DJ. Revisiting the putative role of heme as a trigger of inflammation. Pharmacol Res Perspect 2018; 6:e00392. [PMID: 29610666 PMCID: PMC5878102 DOI: 10.1002/prp2.392] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/11/2018] [Indexed: 12/23/2022] Open
Abstract
Activation of the innate immune system by free heme has been proposed as one of the principal consequences of cell‐free hemoglobin (Hb) exposure. Nonetheless, in the absence of infection, heme exposures within a hematoma, during hemolysis, or upon systemic administration of Hb (eg, as a Hb‐based oxygen carrier) are typically not accompanied by uncontrolled inflammation, challenging the assumption that heme is a major proinflammatory mediator in vivo. Because of its hydrophobic nature, heme liberated from oxidized hemoglobin is rapidly transferred to alternative protein‐binding sites (eg, albumin) or to hydrophobic lipid compartments minimizing protein‐free heme under in vivo equilibrium conditions. We demonstrate that the capacity of heme to activate human neutrophil granulocytes strictly depends on the availability of non protein‐associated heme. In human endothelial cells as well as in mouse macrophage cell cultures and in mouse models of local and systemic heme exposure, protein‐associated heme or Hb do not induce inflammatory gene expression over a broad range of exposure conditions. Only experiments in protein‐free culture medium demonstrated a weak capacity of heme‐solutions to induce toll‐like receptor‐(TLR4) dependent TNF‐alpha expression in macrophages. Our data suggests that the equilibrium‐state of free and protein‐associated heme critically determines the proinflammatory capacity of the metallo‐porphyrin. Based on these data it appears unlikely that inflammation‐promoting equilibrium conditions could ever occur in vivo.
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Affiliation(s)
| | | | - Jeremy W Deuel
- Division of Internal Medicine University of Zurich Zurich Switzerland
| | - Giada Ingoglia
- Division of Internal Medicine University of Zurich Zurich Switzerland
| | - Rok Humar
- Division of Internal Medicine University of Zurich Zurich Switzerland
| | - Paul W Buehler
- Center of Biologics Evaluation and Research (CBER) FDA Silver Spring MD USA
| | - Dominik J Schaer
- Division of Internal Medicine University of Zurich Zurich Switzerland
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16
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Humar R. [Not Available]. Praxis (Bern 1994) 2018; 107:1125. [PMID: 30326816 DOI: 10.1024/1661-8157/a003082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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17
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Drägert K, Bhattacharya I, Hall MN, Humar R, Battegay E, Haas E. Basal mTORC2 activity and expression of its components display diurnal variation in mouse perivascular adipose tissue. Biochem Biophys Res Commun 2016; 473:317-322. [PMID: 27016480 DOI: 10.1016/j.bbrc.2016.03.102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 03/21/2016] [Indexed: 10/22/2022]
Abstract
In adipose tissue mTOR complex 2 (mTORC2) contributes to the regulation of glucose/lipid metabolism and inflammatory molecule expression. Both processes display diurnal variations during the course of the day. RICTOR and mSIN1 are unique and essential components of mTORC2, which is activated by growth factors including insulin. To assess whether mTORC2 components display diurnal variations, we analyzed steady state mRNA expression levels of Rictor, mSin1, and mTor in various adipose tissues during a 24 h period. Diurnally regulated expression of Rictor was detected in brown adipose tissues displaying highest mRNA expression levels at the beginning of the 12 h light period (zeitgeber time 2, ZT2). Gene expression patterns of mSin1 and mTor displayed a similar diurnal regulation as Rictor in PVAT while smaller changes were detected for these genes in aorta during the course of the day. Basal mTORC2 activity was measured by phosphorylation of protein kinase C (PKC) α at serine 657 was higher at ZT14 as compared with ZT2 in PVAT. In line, gene expression of inflammatory molecules nitric oxide synthase 2 and tumor necrosis factor α was lower at ZT 14 compared to ZT2. Our findings provide evidence for a diurnal regulation of expression of mTORC2 components and activity. Hence, mTORC2 is possibly an integral part of diurnally regulated signaling pathways in PVAT and possibly in other adipose tissues.
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Affiliation(s)
- Katja Drägert
- Research Unit, Department of Internal Medicine, University Hospital Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Switzerland
| | - Indranil Bhattacharya
- Research Unit, Department of Internal Medicine, University Hospital Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Switzerland
| | | | - Rok Humar
- Research Unit, Department of Internal Medicine, University Hospital Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Switzerland
| | - Edouard Battegay
- Research Unit, Department of Internal Medicine, University Hospital Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland
| | - Elvira Haas
- Research Unit, Department of Internal Medicine, University Hospital Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program "Dynamics of Healthy Aging", University of Zurich, Switzerland.
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18
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Drägert K, Bhattacharya I, Pellegrini G, Seebeck P, Azzi A, Brown SA, Georgiopoulou S, Held U, Blyszczuk P, Arras M, Humar R, Hall MN, Battegay E, Haas E. Deletion of
Rictor
in Brain and Fat Alters Peripheral Clock Gene Expression and Increases Blood Pressure. Hypertension 2015; 66:332-9. [DOI: 10.1161/hypertensionaha.115.05398] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/26/2015] [Indexed: 01/01/2023]
Affiliation(s)
- Katja Drägert
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Indranil Bhattacharya
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Giovanni Pellegrini
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Petra Seebeck
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Abdelhalim Azzi
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Steven A. Brown
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Stavroula Georgiopoulou
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Ulrike Held
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Przemyslaw Blyszczuk
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Margarete Arras
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Rok Humar
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Michael N. Hall
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Edouard Battegay
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
| | - Elvira Haas
- From the Research Unit, Department of Internal Medicine (K.D., I.B., S.G., R.H, E.B., E.H.) and Division of Surgical Research (M.A.), University Hospital Zurich, Zurich, Switzerland; Center of Competence Multimorbidity and University Research Priority Program “Dynamics of Healthy Aging” (K.D., I.B., S.G., R.H, E.B., E.H.), Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, Vetsuisse faculty (G.P.), Zurich Integrative Rodent Physiology (P.S.), Institute of Pharmacology and
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Bhattacharya I, Domínguez AP, Drägert K, Humar R, Haas E, Battegay EJ. Hypoxia potentiates tumor necrosis factor-α induced expression of inducible nitric oxide synthase and cyclooxygenase-2 in white and brown adipocytes. Biochem Biophys Res Commun 2015; 461:287-92. [DOI: 10.1016/j.bbrc.2015.04.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 04/03/2015] [Indexed: 01/04/2023]
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20
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Oberkofler CE, Limani P, Jang JH, Rickenbacher A, Lehmann K, Raptis DA, Ungethuem U, Tian Y, Grabliauskaite K, Humar R, Graf R, Humar B, Clavien PA. Systemic protection through remote ischemic preconditioning is spread by platelet-dependent signaling in mice. Hepatology 2014; 60:1409-17. [PMID: 24700614 DOI: 10.1002/hep.27089] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 02/19/2014] [Indexed: 12/13/2022]
Abstract
UNLABELLED Remote ischemic preconditioning (RIPC), the repetitive transient mechanical obstruction of vessels at a limb remote to the operative site, is a novel strategy to mitigate distant organ injury associated with surgery. In the clinic, RIPC has demonstrated efficacy in protecting various organs against ischemia reperfusion (IR), but a common mechanism underlying the systemic protection has not been identified. Here, we reasoned that protection may rely on adaptive physiological responses toward local stress, as is incurred through RIPC. Standardized mouse models of partial hepatic IR and of RIPC to the femoral vascular bundle were applied. The roles of platelets, peripheral serotonin, and circulating vascular endothelial growth factor (Vegf) were studied in thrombocytopenic mice, Tph1(-) (/) (-) mice, and through neutralizing antibodies, respectively. Models of interleukin-10 (Il10) and matrix metalloproteinase 8 (Mmp8) deficiency were used to assess downstream effectors of organ protection. The protection against hepatic IR through RIPC was dependent on platelet-derived serotonin. Downstream of serotonin, systemic protection was spread through up-regulation of circulating Vegf. Both RIPC and serotonin-Vegf induced differential gene expression in target organs, with Il10 and Mmp8 displaying consistent up-regulation across all organs investigated. Concerted inhibition of both molecules abolished the protective effects of RIPC. RIPC was able to mitigate pancreatitis, indicating that it can protect beyond ischemic insults. CONCLUSIONS We have identified a platelet-serotonin-Vegf-Il10/Mmp8 axis that mediates the protective effects of RIPC. The systemic action, the conservation of RIPC effects among mice and humans, and the protection beyond ischemic insults suggest that the platelet-dependent axis has evolved as a preemptive response to local stress, priming the body against impending harm.
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Affiliation(s)
- Christian E Oberkofler
- Laboratory of the Swiss Hepato-Pancreatico-Biliary (HPB) Center, Department of Surgery, University Hospital Zurich, Zurich, Switzerland
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21
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Drägert K, Bhattacharya I, Haas E, Humar R, Battegay E, Seebeck P, Held U, Brown S, Hall MN. Abstract 514: Knockout of Rictor in Adipocytes Compromises Anticontractile Function of PVAT and Increases Mean Arterial Pressure. Arterioscler Thromb Vasc Biol 2014. [DOI: 10.1161/atvb.34.suppl_1.514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction:
Mammalian target of rapamycin (mTOR) is a kinase found in two distinct complexes: mTORC1 and mTORC2. The latter is activated by growth factors such as insulin and characterized by the adaptor protein rictor. mTORC2 controls essential functions in white adipose tissue, while little is known about its role in perivascular adipose tissue (PVAT), surrounding most arteries. PVAT is an important regulator of the vascular tone and we have shown that mTORC2 is necessary for normal PVAT function. In the present study we assessed whether adipose mTORC2 contributes to blood pressure regulation and investigated the diurnal expression of mTORC2 phosphorylation targets and circadian clock in PVAT.
Methods:
Experiments were performed with male adipose-specific
rictor
knockout mice (
rictor
ad-/-
) and control littermates (18-23 weeks of age). Vascular function was assessed
ex vivo
using aortic rings with or without PVAT treated with 5-hydroxytrypthamine (5-HT; 10
-9
- 3x10
-6
mol/l). Blood pressure recordings were performed using radiotelemetry monitoring hemodynamic parameters over 7 days (n = 5-6). mRNA and protein levels were analyzed by performing qRT-PCR and Western Blot.
Results:
In
rictor
ad-/-
mice, vascular maximal contractions of aortic rings in the presence of PVAT were 2-fold higher after stimulation with 5-HT compared with control mice (43.4% ± 6.8% vs. 26.0% ± 3.5%, n= 13
)
. Removal of PVAT resulted in increased contraction with similar maximum levels in both mice groups. Blood pressure recordings revealed a significant increase in the 24-h average of mean arterial pressure (103.9 ± 1.1 vs. 98.5 ± 1.4 mmHg) and diastolic arterial pressure (94.6 ± 1.4 vs. 90.2 ± 0.6 mmHg) in
rictor
ad -/-
mice, while systolic arterial pressure and pulse pressure were not significantly different between groups. Interestingly, differences in mean and diastolic arterial pressure were slightly higher during dark as compared to light period. Expression levels of clock genes were similar while expression of mTORC2 phosphorylation targets such as Foxo1 and Sgk1 was dampened in
rictor
ad-/-
mice.
Conclusion:
mTORC2 in adipose tissue regulates mean arterial pressure potentially by affecting diurnal expression and activation of phosphorylation targets such as Foxo1.
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Affiliation(s)
- Katja Drägert
- Rsch Div Internal Medicine, Univ Hosp Zurich, Zurich, Switzerland
| | | | - Elvira Haas
- Rsch Div Internal Medicine, Univ Hosp Zurich, Zurich, Switzerland
| | - Rok Humar
- Rsch Div Internal Medicine, Univ Hosp Zurich, Zurich, Switzerland
| | | | - Petra Seebeck
- Zurich Integrative Rodent Physiology, Univ of Zurich, Zurich, Switzerland
| | - Ulrike Held
- Horten Cntr, Univ Hosp Zurich, Zurich, Switzerland
| | - Steve Brown
- Institute of Pharmacology and Toxicology, Univ of Zurich, Zurich, Switzerland
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22
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Bhattacharya I, Drägert K, Albert V, Contassot E, Damjanovic M, Hagiwara A, Zimmerli L, Humar R, Hall MN, Battegay EJ, Haas E. Rictor in perivascular adipose tissue controls vascular function by regulating inflammatory molecule expression. Arterioscler Thromb Vasc Biol 2013; 33:2105-11. [PMID: 23868942 DOI: 10.1161/atvbaha.112.301001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Perivascular adipose tissue (PVAT) wraps blood vessels and modulates vasoreactivity by secretion of vasoactive molecules. Mammalian target of rapamycin complex 2 (mTORC2) has been shown to control inflammation and is expressed in adipose tissue. In this study, we investigated whether adipose-specific deletion of rictor and thereby inactivation of mTORC2 in PVAT may modulate vascular function by increasing inflammation in PVAT. APPROACH AND RESULTS Rictor, an essential mTORC2 component, was deleted specifically in mouse adipose tissue (rictor(ad-/-)). Phosphorylation of mTORC2 downstream target Akt at Serine 473 was reduced in PVAT from rictor(ad-/-) mice but unaffected in aortic tissue. Ex vivo functional analysis of thoracic aortae revealed increased contractions and impaired dilation in rings with PVAT from rictor(ad-/-) mice. Adipose rictor knockout increased gene expression and protein release of interleukin-6, macrophage inflammatory protein-1α, and tumor necrosis factor-α in PVAT as shown by quantitative real-time polymerase chain reaction and Bioplex analysis for the cytokines in the conditioned media, respectively. Moreover, gene and protein expression of inducible nitric oxide synthase was upregulated without affecting macrophage infiltration in PVAT from rictor(ad-/-) mice. Inhibition of inducible nitric oxide synthase normalized vascular reactivity in aortic rings from rictor(ad-/-) mice with no effect in rictor(fl/fl) mice. Interestingly, in perivascular and epididymal adipose depots, high-fat diet feeding induced downregulation of rictor gene expression. CONCLUSIONS Here, we identify mTORC2 as a critical regulator of PVAT-directed protection of normal vascular tone. Modulation of mTORC2 activity in adipose tissue may be a potential therapeutic approach for inflammation-related vascular damage.
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Affiliation(s)
- Indranil Bhattacharya
- Research Unit, Division of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
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23
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Peier M, Walpen T, Christofori G, Battegay E, Humar R. Sprouty2 expression controls endothelial monolayer integrity and quiescence. Angiogenesis 2012; 16:455-68. [PMID: 23232625 DOI: 10.1007/s10456-012-9330-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 12/02/2012] [Indexed: 12/12/2022]
Abstract
Vascular integrity is fundamental to the formation of mature blood vessels and depends on a functional, quiescent endothelial monolayer. However, how endothelial cells enter and maintain quiescence in the presence of angiogenic factors is still poorly understood. Here we identify the fibroblast growth factor (FGF) antagonist Sprouty2 (Spry2) as a key player in mediating endothelial quiescence and barrier integrity in mouse aortic endothelial cells (MAECs): Spry2 knockout MAECs show spindle-like shapes and are incapable of forming a functional, impermeable endothelial monolayer in the presence of FGF2. Whereas dense wild type cells exhibit contact inhibition and stop to proliferate, Spry2 knockout MAECs remain responsive to FGF2 and continue to proliferate even at high cell densities. Importantly, the anti-proliferative effect of Spry2 is absent in sparsely plated cells. This cell density-dependent Spry2 function correlates with highly increased Spry2 expression in confluent wild type MAECs. Spry2 protein expression is barely detectable in single cells but steadily increases in cells growing to high cell densities, with hypoxia being one contributing factor. At confluence, Spry2 expression correlates with intact cell-cell contacts, whereas disruption of cell-cell contacts by EGTA, TNFα and thrombin decreases Spry2 protein expression. In confluent cells, high Spry2 levels correlate with decreased extracellular signal-regulated kinase 1/2 (Erk1/2) phosphorylation. In contrast, dense Spry2 knockout MAECs exhibit enhanced signaling by Erk1/2. Moreover, inhibiting Erk1/2 activity in Spry2 knockout cells restores wild type cobblestone monolayer morphology. This study thus reveals a novel Spry2 function, which mediates endothelial contact inhibition and barrier integrity.
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Affiliation(s)
- Martin Peier
- Division of Internal Medicine, University Hospital Zurich, Gloriastrasse 30, GLO30 J14, 8091, Zurich, Switzerland
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24
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Walpen T, Kalus I, Schwaller J, Peier MA, Battegay EJ, Humar R. Nuclear PIM1 confers resistance to rapamycin-impaired endothelial proliferation. Biochem Biophys Res Commun 2012; 429:24-30. [PMID: 23131564 DOI: 10.1016/j.bbrc.2012.10.106] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 10/24/2012] [Indexed: 01/15/2023]
Abstract
The PIM serine/threonine kinases and the mTOR/AKT pathway integrate growth factor signaling and promote cell proliferation and survival. They both share phosphorylation targets and have overlapping functions, which can partially substitute for each other. In cancer cells PIM kinases have been reported to produce resistance to mTOR inhibition by rapamycin. Tumor growth depends highly on blood vessel infiltration into the malignant tissue and therefore on endothelial cell proliferation. We therefore investigated how the PIM1 kinase modulates growth inhibitory effects of rapamycin in mouse aortic endothelial cells (MAEC). We found that proliferation of MAEC lacking Pim1 was significantly more sensitive to rapamycin inhibition, compared to wildtype cells. Inhibition of mTOR and AKT in normal MAEC resulted in significantly elevated PIM1 protein levels in the cytosol and in the nucleus. We observed that truncation of the C-terminal part of Pim1 beyond Ser 276 resulted in almost exclusive nuclear localization of the protein. Re-expression of this Pim1 deletion mutant significantly increased the proliferation of Pim1(-/-) cells when compared to expression of the wildtype Pim1 cDNA. Finally, overexpression of the nuclear localization mutant and the wildtype Pim1 resulted in complete resistance to growth inhibition by rapamycin. Thus, mTOR inhibition-induced nuclear accumulation of PIM1 or expression of a nuclear C-terminal PIM1 truncation mutant is sufficient to increase endothelial cell proliferation, suggesting that nuclear localization of PIM1 is important for resistance of MAEC to rapamycin-mediated inhibition of proliferation.
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Affiliation(s)
- Thomas Walpen
- Research Unit, Division Internal Medicine, University Hospital Zürich, 8091 Zürich, Switzerland
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25
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Walpen T, Peier M, Haas E, Kalus I, Schwaller J, Battegay E, Humar R. Loss ofPim1Imposes a Hyperadhesive Phenotype on Endothelial Cells. Cell Physiol Biochem 2012. [DOI: 10.1159/000341484] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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26
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Sanchez de Miguel L, Neysari S, Jakob S, Petrimpol M, Butz N, Banfi A, Zaugg CE, Humar R, Battegay EJ. B2-kinin receptor plays a key role in B1-, angiotensin converting enzyme inhibitor-, and vascular endothelial growth factor-stimulated in vitro angiogenesis in the hypoxic mouse heart. Cardiovasc Res 2008; 80:106-13. [PMID: 18566101 DOI: 10.1093/cvr/cvn170] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Angiotensin converting enzyme (ACE) inhibition reduces heart disease and vascular stiffness in hypertension and leads to kinin accumulation. In this study, we analysed the role and importance of two kinin receptor subtypes in angiogenesis during ACE inhibition in an in vitro model of angiogenesis of the mouse heart. METHODS AND RESULTS First, we analysed the angiogenic properties of bradykinin and enalapril on wild-type C57Bl/6 and B2 receptor(-/-) mouse heart under normoxia (21% O(2)) and hypoxia (1% O(2)) in vitro and the contribution of B1 and B2 kinin receptors to this effect. Bradykinin induced dose-dependent endothelial sprout formation in vitro in adult mouse heart only under hypoxia (1.7 fold, n = 6, P < 0.05). The B2 receptor mediated sprouting that was induced by bradykinin and vascular endothelial growth factor (VEGF(164); n = 6, P < 0.05), but did not mediate sprouting that was induced by growth factors bFGF or PDGF-BB. Enalapril induced sprouting through both the B1 and B2 kinin receptors, but it required the presence of the B2 receptor in both scenarios and was dependent on BK synthesis. B1-receptor agonists induced sprout formation via the B1 receptor (2.5 fold, n = 6, P < 0.05), but it required the presence of the B2 receptor for them to do so. Both B2-receptor and B1-receptor agonist-induced angiogenesis required nitric oxide biosynthesis. CONCLUSION The kinin B2 receptor plays a crucial role in angiogenesis that is induced by different vasoactive molecules, namely bradykinin, ACE inhibitors, B1-stimulating kinin metabolites, and VEGF164 in an in vitro model of angiogenesis of mouse heart under hypoxia. Therapeutic treatment of hypertensive patients by using ACE inhibitors may potentially benefit the ischaemic heart through inducing B2-dependent heart neovascularization.
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27
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Munk VC, Sanchez de Miguel L, Petrimpol M, Butz N, Banfi A, Eriksson U, Hein L, Humar R, Battegay EJ. Angiotensin II Induces Angiogenesis in the Hypoxic Adult Mouse Heart In Vitro Through an AT
2
–B2 Receptor Pathway. Hypertension 2007; 49:1178-85. [PMID: 17339539 DOI: 10.1161/hypertensionaha.106.080242] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiotensin II is a vasoactive peptide that may affect vascularization of the ischemic heart via angiogenesis. In this study we aimed at studying the mechanisms underlying the angiogenic effects of angiotensin II under hypoxia in the mouse heart in vitro. Endothelial sprout formation from pieces of mouse hearts was assessed under normoxia (21% O
2
) and hypoxia (1% O
2
) during a 7-day period of in vitro culture. Only under hypoxia did angiotensin II dose-dependently induce endothelial sprout formation, peaking at 10
−7
mol/L of angiotensin II. Angiotensin II type 1 (AT
1
) receptor blockade by losartan did not affect angiotensin II–induced sprouting in wild-type mice. Conversely, the angiotensin II type 2 (AT
2
) receptor antagonist PD 123319 blocked this response. In hearts from AT
1
−/−
mice, angiotensin II–elicited sprouting was preserved but blocked again by AT
2
receptor antagonism. In contrast, no angiotensin II–induced sprouting was found in preparations from hearts of AT
2
−/−
mice. Angiotensin II–mediated angiogenesis was also abolished by a specific inhibitor of the B2 kinin receptor in both wild-type and AT
1
−/−
mice. Furthermore, angiotensin II failed to induce endothelial sprout formation in hearts from B2
−/−
mice. Finally, NO inhibition completely blunted sprouting in hearts from wild-type mice, whereas NO donors could restore sprouting in AT
2
−/−
and B2
−/−
hearts. This in vitro study suggests the obligatory role of hypoxia in the angiogenic effect of angiotensin II in the mouse heart via the AT
2
receptor through a mechanism that involves bradykinin, its B2 receptor, and NO as a downstream effector.
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MESH Headings
- Angiotensin II/administration & dosage
- Angiotensin II/pharmacology
- Animals
- Coronary Vessels/drug effects
- Coronary Vessels/physiopathology
- Dose-Response Relationship, Drug
- Hypoxia/metabolism
- Hypoxia/physiopathology
- In Vitro Techniques
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Neovascularization, Physiologic
- Nitric Oxide/metabolism
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/deficiency
- Receptor, Angiotensin, Type 2/metabolism
- Receptor, Bradykinin B2/deficiency
- Receptor, Bradykinin B2/metabolism
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Affiliation(s)
- Veronica C Munk
- Department of Research, Laboratory of Vascular Biology, University Hospital, Basel, Switzerland
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28
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Battegay EJ, de Miguel LS, Petrimpol M, Humar R. Effects of anti-hypertensive drugs on vessel rarefaction. Curr Opin Pharmacol 2007; 7:151-7. [PMID: 17276727 DOI: 10.1016/j.coph.2006.09.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Accepted: 09/29/2006] [Indexed: 10/23/2022]
Abstract
The microcirculation largely determines peripheral vascular resistance and substantially contributes to arterial hypertension. In both human arterial hypertension and animal models of hypertension, genetic, fetal and other mechanisms associated with hypertension can reduce the formation and number of microvessels (i.e. parallel-connected arterioles and capillaries). Impaired formation of microvessels (impaired angiogenesis) and microvascular rarefaction can, on the other hand, contribute to increased peripheral resistance and raise blood pressure. Interestingly, drugs targeting the renin-angiotensin-aldosterone system (i.e. angiotensin-converting enzyme inhibitors and AT(1) receptor blockers) induce angiogenesis in vivo in the majority of animal studies. Furthermore, recent clinical studies demonstrate that long-term antihypertensive treatment increases capillary density in the skin of hypertensive patients without diabetes. These effects of angiotensin-converting enzyme inhibitors and AT(1) receptor blockers can be mediated by activation of bradykinin pathways, resulting in the generation of vascular endothelial growth factor, nitric oxide and, consequently, angiogenesis. In conclusion, specific antihypertensive drugs can induce angiogenesis and reduce or even reverse microvascular rarefaction. This might improve target organ damage in, and slow the development of, hypertension.
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Affiliation(s)
- Edouard J Battegay
- Department of Internal Medicine Ambulatory Internal Medicine, Hypertension Clinic, University Hospital, Basel, Switzerland.
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29
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Humar R, de Miguel LS, Kiefer FN, Battegay EJ. Formation of new blood vessels in the heart can be studied in cell cultures. ALTEX 2007; 24 Spec No:35-38. [PMID: 19835053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Controlled induction of the formation of new microvessels, i.e., therapeutic angiogenesis, may be used one day to treat patients that for example had suffered a myocardial infarction. Experimental models of angiogenesis in the heart in vivo substantially stress the animal. We therefore developed a model of angiogenesis of the heart in vitro, where mouse and rat heart pieces are stimulated under controlled conditions in a three dimensional matrix. Capillary-like sprouts emerging in these cultures represent early to midterm steps of angiogenesis and can be quantified to study potential angiogenic compounds and underlying mechanisms.
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Affiliation(s)
- Rok Humar
- Department of Research, University Hospital Basel, Basel, Switzerland.
| | | | | | | |
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30
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Abstract
A central regulator of cell growth that has been implicated in responses to stress such as hypoxia is mTOR (mammalian Target Of Rapamycin). We have shown previously that mTOR is required for angiogenesis in vitro and endothelial cell proliferation in response to hypoxia. Here we have investigated mTOR-associated signaling components under hypoxia and their effects on cell proliferation in rat aortic endothelial cells (RAECs). Hypoxia (1% O(2)) rapidly (>30 minutes) and in a concentration-dependent manner promoted rapamycin-sensitive and sustained phosphorylation of mTOR-Ser2448 followed by nuclear translocation in RAECs. Similarly, hypoxia induced phosphorylation of the mTORC2 substrate Akt-Ser473 (3 to 6 hours at 1% O(2)) and a brief phosphorylation peak of the mTORC1 substrate S6 kinase-Thr389 (10 to 60 minutes). Phosphorylation of Akt was inhibited by mTOR knockdown and partially with rapamycin. mTOR knockdown, rapamycin, or Akt inhibition specifically and significantly inhibited proliferation of serum-starved RAECs under hypoxia (P<0.05; n> or =4). Similarly, hypoxia induced Akt-dependent and rapamycin-sensitive proliferation in mouse embryonic fibroblasts. This response was partially blunted by hypoxia-inducible factor-1alpha knockdown and not affected by TSC2 knockout. Finally, mTORC2 inhibition by rictor silencing, especially (P<0.001; n=7), and mTORC1 inhibition by raptor silencing, partially (P<0.05; n=7), inhibited hypoxia-induced RAEC proliferation. Thus, mTOR mediates an early response to hypoxia via mTORC1 followed by mTORC2, promoting endothelial proliferation mainly via Akt signaling. mTORC1 and especially mTORC2 might therefore play important roles in diseases associated with hypoxia and altered angiogenesis.
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Affiliation(s)
- Weimin Li
- Department of Research, University Hospital Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland
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31
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Kiefer FN, Munk VC, Humar R, Dieterle T, Landmann L, Battegay EJ. A versatile in vitro assay for investigating angiogenesis of the heart. Exp Cell Res 2004; 300:272-82. [PMID: 15474993 DOI: 10.1016/j.yexcr.2004.06.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 06/17/2004] [Indexed: 11/22/2022]
Abstract
Neovascularization in the heart is usually investigated with models of angiogenesis in vivo. Here we present a simple model that allows investigating heart angiogenesis in mice and rats in vitro. Small pieces of left ventricular myocardium were cultured in three-dimensional fibrin gels for 10 days. A single mouse heart allowed assessing 24 conditions, each tested in octuplicates. Rat recombinant VEGF164, human recombinant bFGF, and human recombinant PDGF-BB were used under normoxia (21% O2) and hypoxia (3% O2), and outgrowth of endothelial sprouts from heart pieces was quantified. In 4-week-old OF1 mice, endothelial sprouts formed spontaneously. In contrast, in 12-week-old adult mice, virtually no sprouts formed under normoxia. Under hypoxia, sprout formation increased substantially. Different growth factors induced formation of distinct patterns of sprouts and unorganized single cells. Sprouts were composed of endothelial cells with smooth muscle cells or pericytes interacting with them, as assessed by immunohistochemistry. Taken together, our model is suited for investigation of angiogenesis of the heart in vitro. It may allow performing extensive series of experiments in vitro including rapid screening of pharmacological compounds and assessment of mechanisms of heart angiogenesis in transgenic animals in an easy straightforward manner.
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Affiliation(s)
- Fabrice N Kiefer
- Department of Research, University Hospital, CH-4031 Basel, Switzerland
| | | | | | | | | | | |
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32
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Abstract
Arterial Hypertension (AH) is characterized by reduced nitric oxide (NO) biosynthesis, activation of the Renin-Angiotensin-Aldosteron-System (RAAS), vasoconstriction, and microvascular rarefaction. The latter contributes to target organ damage, especially in left ventricular hypertrophy, and may partially be due to impaired angiogenesis. Angiogenesis, the formation of new microvessels and microvascular networks from existing ones, is a highly regulated process that arises in response to hypoxia and other stimuli and that relieves tissue ischemia. In AH, angiogenesis seems impaired. However, blood pressure alone does not affect angiogenesis, and microvascular rarefaction is present in normotensive persons with a family history for AH. Normal or increased NO in several processes and diseases enables or enhances angiogenesis (e.g. in portal hypertension) and reduced NO biosynthesis (for example, in a rat model of AH, in other disease models in vivo, and in endothelial NO Synthase knock out mice) impairs angiogenesis. Angiogenic growth factors such as Vascular Endothelial Growth Factor (VEGF) and Fibroblast Growth Factor (FGF) induce NO and require NO to elicit an effect. Effector molecules and corresponding receptors of the RAAS either induce (Bradykinin, Angiotensin II) or perhaps inhibit angiogenesis. The pattern of Bradykinin- and Angiotensin II-receptor expression and the capacity to normalize NO biosynthesis may determine whether ACE-inhibitors, Angiotensin II-receptor antagonists and other substances affect angiogenesis. Reconstitution of a normally vascularized tissue by reversal of impaired angiogenesis with drugs such as ACE inhibitors and AT1 receptor antagonists may contribute to successful treatment of hypertension-associated target organ damage, e.g. left ventricular hypertrophy.
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Affiliation(s)
- F N Kiefer
- Medical Outpatient Department and Department of Research, University Hospital, CH-4031 Basel, Switzerland
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33
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Humar R, Kiefer FN, Berns H, Resink TJ, Battegay EJ. Hypoxia enhances vascular cell proliferation and angiogenesis in vitro via rapamycin (mTOR)-dependent signaling. FASEB J 2002; 16:771-80. [PMID: 12039858 DOI: 10.1096/fj.01-0658com] [Citation(s) in RCA: 312] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Angiogenesis and vascular cell proliferation are pivotal in physiological and pathological processes including atherogenesis, restenosis, wound healing, and cancer development. Here we show that mammalian target of rapamycin (mTOR) signaling plays a key role in hypoxia-triggered smooth muscle and endothelial proliferation and angiogenesis in vitro. Hypoxia significantly increased DNA synthesis and proliferative responses to platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) in rat and human smooth muscle and endothelial cells. In an in vitro 3-dimensional model of angiogenesis, hypoxia increased PDGF- and FGF-stimulated sprout formation from rat and mouse aortas. Hypoxia did not modulate PDGF receptor mRNA, protein, or phosphorylation. PI3K activity was essential for cell proliferation under normoxic and hypoxic conditions. Activities of PI3K-downstream target PKB under hypoxia and normoxia were comparable. However, mTOR inhibition by rapamycin specifically abrogated hypoxia-mediated amplification of proliferation and angiogenesis, but was without effect on proliferation under normoxia. Accordingly, hypoxia-mediated amplification of proliferation was further augmented in mTOR-overexpressing endothelial cells. Thus, signaling via mTOR may represent a novel mechanism whereby hypoxia augments mitogen-stimulated vascular cell proliferation and angiogenesis.
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MESH Headings
- 3T3 Cells
- Animals
- Cell Division/drug effects
- Cell Hypoxia/physiology
- Cells, Cultured
- Chromones/pharmacology
- DNA/biosynthesis
- DNA/drug effects
- Dose-Response Relationship, Drug
- Fibroblast Growth Factor 2/pharmacology
- Mice
- Models, Biological
- Morpholines/pharmacology
- Muscle, Smooth, Vascular/blood supply
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Neovascularization, Physiologic/drug effects
- Neovascularization, Physiologic/physiology
- Phosphatidylinositol 3-Kinases/drug effects
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphorylation
- Platelet-Derived Growth Factor/pharmacology
- Protein Kinases/genetics
- Protein Kinases/metabolism
- Protein Serine-Threonine Kinases
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Receptors, Platelet-Derived Growth Factor/drug effects
- Receptors, Platelet-Derived Growth Factor/genetics
- Receptors, Platelet-Derived Growth Factor/metabolism
- Sirolimus/pharmacology
- TOR Serine-Threonine Kinases
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Affiliation(s)
- Rok Humar
- Department of Research and, University Medical Outpatient Department, University Hospital, CH-4031 Basel, Switzerland
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Abstract
Angiogenesis is crucial for many biological and pathological processes including the ovarian cycle and tumor growth. To identify molecules relevant for angiogenesis, we performed mRNA fingerprinting and subsequent Northern blot analysis using bovine cord-forming vs. monolayer-forming endothelial cells (EC) in vitro and staged bovine corpora lutea in vivo. We detected the receptor for activated C kinase 1 (RACK1), the specific receptor for activated protein kinase C beta (PKC beta), to be up-regulated in bovine cord-forming EC in vitro and in angiogenically active stages of bovine corpora lutea in vivo. Thereafter we established and determined the complete bovine RACK1 cDNA sequence. RACK1 was massively induced in subconfluent vs. contact-inhibited bovine EC, during angiogenesis in vitro, active phases of the murine ovarian cycle, human tumor angiogenesis, and in cancer cells in vivo as assessed by quantitative PCR and in situ hybridization. RACK1 transcripts were localized to proliferating EC in vitro and the endothelium of tumor neovascularizations in vivo by in situ hybridization. PKC beta plays an important role in angiogenesis and cancer growth. Our data suggest that downstream signaling of PKC beta in angiogenically active vs. inactive tissues and endothelium is affected by the availability of RACK1.
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Affiliation(s)
- H Berns
- Cardiovascular Research Group, Department of Research, University Hospital, basel, Switzerland
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Thommen R, Humar R, Misevic G, Pepper MS, Hahn AW, John M, Battegay EJ. PDGF-BB increases endothelial migration on cord movements during angiogenesis in vitro. J Cell Biochem 1997; 64:403-13. [PMID: 9057098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To explore direct effects of platelet-derived growth factor (PDGF) on endothelial cells during angiogenesis in vitro, we have used cloned bovine aortic endothelial cells that spontaneously form cord structures. Recently we have shown that cells forming these endothelial cords express PDGF beta-receptors and that PDGF-BB can contribute to cellular proliferation and cord formation. In this study we investigated whether PDGF-induced cellular migration might also contribute to endothelial repair and angiogenesis in vitro. Ten individual endothelial cells in cords were tracked at an early stage of cord formation by video-timelapse microscopy. PDGF-BB (100 ng/ml) induced an increase in endothelial cell movement of 67 +/- 15% as compared with diluent control. Interestingly, PDGF-BB also increased movements of entire cord structures, followed at branching points, by 53 +/- 12% over diluent control. Taken together, these video-timelapse experiments suggested that the apparent movements of single endothelial cord cells might also be due to the motion of entire underlying cord structures in response to PDGF. To analyze the response of single endothelial cord cells we therefore examined whether PDGF-induced migration contributes to endothelial repair. Abrasions were applied with a razor blade to confluent monolayers of endothelial cells at an intermediate stage of cord formation. PDGF-BB concentration-dependently increased the distance to which cord-forming endothelial cells migrated into the abrasion. An increased number of elongated, i.e., probably migrating, endothelial cells was found in the abrasion in response to PDGF-BB. However, there was no effect of PDGF-BB on the total number of endothelial cells found in the abrasion. PDGF-AA affected neither the distance to which the cells migrated nor the number of elongated cells. Actin and tubulin stainings revealed that these cytoskeletal structures were not appreciably altered by PDGF-BB. Furthermore, urokinase-type plasminogen activator transcripts were not modulated in response to PDGF-BB. We conclude that in this model of angiogenesis in vitro PDGF-BB can elicit the movement of entire cord structures, possibly via u-PA-independent mechanisms. PDGF-BB also controls the migration of single cord-forming endothelial cells. Thus, PDGF-BB possibly contributes to endothelial repair and angiogenesis by direct effects on proliferation and composite movements of PDGF beta-receptor-expressing endothelial cells and cords.
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Affiliation(s)
- R Thommen
- Department of Research, University Hospitals, Basel, Switzerland
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Abstract
Two major phosphoproteins of Plasmodium falciparum could be identified by partial amino acid sequencing as the plasmodial members of the hsp 70 heat shock protein family, Pfhsp and Pfgrp. According to phosphoamino acid analyses of Pfhsp and Pfgrp isolated from [32P]orthophosphate-labeled malarial cultures, both proteins were phosphorylated in Ser and Thr. While Pfhsp contains higher amounts of labeled phosphoserine, Pfgrp contains higher amounts of phosphothreonine. Phosphorylation of both proteins increased throughout the entire erythrocytic growth cycle. At the trophozoite and schizont stages Pfhsp and Pfgrp are the most prominent phosphoproteins of Plasmodium falciparum. Using multiply redundant oligonucleotides directed against the N-terminus of Pfgrp we cloned and sequenced the entire Pfgrp gene. The gene encodes a product with a predicted length of 652 amino acids. The deduced amino acid sequence has identities of 65.5% and 65.0% to the human and rat grp78 proteins, respectively. Pfgrp possesses a classical N-terminal leader sequence. The published grp78 related gene sequences of Plasmodium falciparum are all fragments of the same plasmodial gene.
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Affiliation(s)
- B Kappes
- Department of Structural Biology, University of Basel, Switzerland
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