Einleitung Zusätzlich zu ihrer Bedeutung bei Homöostase und Immunabwehr tragen neutrophile Granulozyten zur Pathogenese des Kopf-Hals-Plattenepithelkarzinoms (HNSCC) bei. Kürzlich wurde gezeigt, dass die Alterung von reifen neutrophilen Granulozyten in der Zirkulation wesentlich für die vollständige Ausprägung der funktionellen Eigenschaften dieser Immunzellen ist. Welche Rolle die Alterung von neutrophilen Granulozyten bei HNSCC spielt ist nicht bekannt.

There is an urgent need to apply effective, data-driven approaches to reliably predict engineered nanomaterial (ENM) toxicity. Here we introduce a predictive computational framework based on the molecular and phenotypic effects of a large panel of ENMs across multiple in vitro and in vivo models. Our methodology allows for the grouping of ENMs based on multi-omics approaches combined with robust toxicity tests. Importantly, we identify mRNA-based toxicity markers and extensively replicate them in multiple independent datasets. We find that models based on combinations of omics-derived features and material intrinsic properties display significantly improved predictive accuracy as compared to physicochemical properties alone.

Background Beyond their fundamental role in homeostasis and host defense, neutrophilic granulocytes (neutrophils) are increasingly recognized to contribute to the pathogenesis of malignant tumors. Recently, aging of mature neutrophils in the systemic circulation has been identified to be critical for these immune cells to properly unfold their homeostatic and anti-infectious functional properties. The role of neutrophil aging in cancer remains largely obscure. Methods Employing advanced in vivo microscopy techniques in different animal models of cancer as well as utilizing pulse-labeling and cell transfer approaches, various ex vivo/in vitro assays, and human data, we sought to define the functional relevance of neutrophil aging in cancer. Results Here, we show that signals released during early tumor growth accelerate biological aging of circulating neutrophils, hence uncoupling biological from chronological aging of these immune cells. This facilitates the accumulation of highly reactive neutrophils in malignant lesions and endows them with potent protumorigenic functions, thus promoting tumor progression. Counteracting uncoupled biological aging of circulating neutrophils by blocking the chemokine receptor CXCR2 effectively suppressed tumor growth. Conclusions Our data uncover a self-sustaining mechanism of malignant neoplasms in fostering protumorigenic phenotypic and functional changes in circulating neutrophils. Interference with this aberrant process might therefore provide a novel, already pharmacologically targetable strategy for cancer immunotherapy.

High intratumoral levels of urokinase-type plasminogen activator (uPA)-plasminogen activator inhibitor-1 (PAI-1) heteromers predict impaired survival and treatment response in early breast cancer. The pathogenetic role of this protein complex remains obscure. Here, we demonstrate that heteromerization of uPA and PAI-1 multiplies the potential of the single proteins to attract pro-tumorigenic neutrophils. To this end, tumor-released uPA-PAI-1 utilizes very low-density lipoprotein receptor and mitogen-activated protein kinases to initiate a pro-inflammatory program in perivascular macrophages. This enforces neutrophil trafficking to cancerous lesions and skews these immune cells toward a pro-tumorigenic phenotype, thus supporting tumor growth and metastasis. Blockade of uPA-PAI-1 heteromerization by a novel small-molecule inhibitor interfered with these events and effectively prevented tumor progression. Our findings identify a therapeutically targetable, hitherto unknown interplay between hemostasis and innate immunity that drives breast cancer progression. As a personalized immunotherapeutic strategy, blockade of uPA-PAI-1 heteromerization might be particularly beneficial for patients with highly aggressive uPA-PAI-1high tumors.

Background High tumor levels of urokinase-type plasminogen activator (uPA)-plasminogen activator inhibitor-1 (PAI-1) heteromers independently predict poor survival in early breast cancer. The pathogenetic role of this protein complex, however, remains largely obscure. Material and Methods Neutrophil trafficking was analyzed in orthotopic (multi-channel flow cytometry) and heterotopic (ear; multi-channel in vivo microscopy) mouse models of 4T1 breast cancer, in a mouse peritonitis assay (multi-channel flow cytometry), as well as in the mouse cremaster muscle (multi-channel in vivo microscopy). Cytokine expression in tumors was determined by multiplex ELISA. Phenotypic and functional properties of primary mouse neutrophils, microvascular endothelial cells (cell line bEnd.3), macrophages (cell line RAW 264.7), and breast cancer cells (cell line 4T1) were characterized in different in vitro assays. uPA/PAI-1 expression and neutrophil infiltration in human breast cancer samples were assessed by RNA sequencing, immunhistochemistry, and ELISA. Results and Discussion Here, we demonstrate that uPA-PAI-1 heteromerization multiplies the potential of the single proteins to attract pro-tumorigenic neutrophils. To this end, tumor-released uPA-PAI-1 activates peritumoral macrophages (VLDL receptor- and ERK/MAPK-pathway). This promotes neutrophil trafficking to cancerous lesions (enhanced β2 integrin activation and clustering) and primes these immune cells towards a pro-tumorigenic phenotype (elevated neutrophil elastase expression), thus supporting tumor growth and metastasis. Blockade of uPA-PAI-1 heteromerization by a novel inhibitor effectively interfered with these events and prevented tumor progression. Conclusions Here, we identified an already therapeutically targetable interplay between hemostasis and innate immunity that drives advanced stages of breast cancer as well as characterized the underlying mechanisms of this process. As a personalized immunotherapeutic strategy, blockade of uPA-PAI-1 heteromerization might be particularly beneficial for patients with highly aggressive uPA-PAI-1high tumors. This study was supported by Deutsche Forschungsgemeinschaft (DFG), Sonderforschungsbereich (SFB) 914 Disclosure Information B. Uhl: None. L. Mittmann: None. J. Dominik: None. R. Hennel: None. B. Smiljanov: None. F. Haring: None. J. Schaubächer: None. C. Braun: None. L. Padovan: None. R. Pick: None. M. Canis: None. C. Schulz: None. M. Mack: None. E. Gutjahr: None. P. Sinn: None. J. Heil: None. K. Steiger: None. S.M. Kanse: None. W. Weichert: None. M. Sperandio: None. K. Lauber: None. F. Krombach: None. C. Reichel: None.

Einleitung Neben ihrer bekannten Funktion bei der Infektabwehr, scheinen neutrophile Granulozyten auch zur Pathogenese von malignen Tumoren beizutragen. Kürzlich wurde gezeigt, dass die Alterung von reifen neutrophilen Granulozyten in der Zirkulation wesentlich an der Ausbildung ihrer anti-infektiösen Eigenschaften beteiligt ist. Welche Bedeutung dieser Alterungsprozess von neutrophilen Granulozyten bei Krebs spielt, ist nicht bekannt.

Background High tumor levels of urokinase-type plasminogen activator (uPA)-plasminogen activator inhibitor-1 (PAI-1) heteromers independently predict poor survival in early breast cancer. The pathogenetic role of this protein complex, however, remains largely obscure. Materials and Methods Neutrophil trafficking was analyzed in orthotopic (multi-channel flow cytometry) and heterotopic (ear; multi-channel in vivo microscopy) mouse models of 4T1 breast cancer, in a mouse peritonitis assay (multi-channel flow cytometry), as well as in the mouse cremaster muscle (multi-channel in vivo microscopy). Cytokine expression in tumors was determined by multiplex ELISA. Phenotypic and functional properties of primary mouse neutrophils, microvascular endothelial cells (cell line bEnd.3), macrophages (cell line RAW 264.7), and breast cancer cells (cell line 4T1) were characterized in different in vitro assays. uPA/PAI-1 expression and neutrophil infiltration in human breast cancer samples were assessed by RNA sequencing, immunhistochemistry, and ELISA. Results Here, we demonstrate that uPA-PAI-1 heteromerization multiplies the potential of the single proteins to attract pro-tumorigenic neutrophils. To this end, tumor-released uPA-PAI-1 utilizes very low density lipoprotein receptor and ERK mitogen-activated protein kinases to initiate a pro-inflammatory program in peritumoral macrophages. This promotes neutrophil trafficking to cancerous lesions and primes these immune cells towards a pro-tumorigenic phenotype, thus supporting tumor growth and metastasis. Blockade of uPA-PAI-1 heteromerization by a novel inhibitor effectively interfered with these events and prevented tumor progression. Conclusions Our findings identify an already therapeutically targetable interplay between hemostasis and innate immunity that drives advanced stages of breast cancer. As a personalized immunotherapeutic strategy, blockade of uPA-PAI-1 heteromerization might be particularly beneficial for patients with highly aggressive uPA-PAI-1hightumors. This study was supported by Deutsche Forschungsgemeinschaft (DFG), Sonderforschungsbereich (SFB) 914. Disclosure Information B. Uhl: None. L. Mittmann: None. J. Dominik: None. J. Schaubächer: None. C. Braun: None. R. Pick: None. M. Canis: None. S. Kanse: None. W. Weichert: None. M. Sperandio: None. K. Lauber: None. F. Krombach: None. C.A. Reichel: None.

The recruitment of neutrophils from the microvasculature to the site of injury or infection represents a key event in the inflammatory response. Vitronectin (VN) is a multifunctional macromolecule abundantly present in blood and extracellular matrix. The role of this glycoprotein in the extravasation process of circulating neutrophils remains elusive. Employing advanced in vivo/ex vivo imaging techniques in different mouse models as well as in vitro methods, we uncovered a previously unrecognized function of VN in the transition of dynamic to static intravascular interactions of neutrophils with microvascular endothelial cells. These distinct properties of VN require the heteromerization of this glycoprotein with plasminogen activator inhibitor-1 (PAI- 1) on the activated venular endothelium and subsequent interactions of this protein complex with the scavenger receptor low-density lipoprotein receptor-related protein-1 on intravascularly adhering neutrophils. This induces p38 mitogen-activated protein kinases-dependent intracellular signaling events which, in turn, regulates the proper clustering of the b2 integrin lymphocyte function associated antigen-1 on the surface of these immune cells. As a consequence of this molecular interplay, neutrophils become able to stabilize their adhesion to the microvascular endothelium and, subsequently, to extravasate to the perivascular tissue. Hence, endothelial-bound VN-PAI-1 heteromers stabilize intravascular adhesion of neutrophils by coordinating b2 integrin clustering on the surface of these immune cells, thereby effectively controlling neutrophil trafficking to inflamed tissue. Targeting this protein complex might be beneficial for the prevention and treatment of inflammatory pathologies.

Background Beyond their well-established role in host defense, neutrophils are increasingly recognized to contribute to the pathogenesis of malignant tumors. Recently, ageing of mature neutrophils in the systemic circulation has been identified to be critical for these immune cells to properly unfold their anti-infectious properties. The role of neutrophil ageing in cancer is still unknown. Material and Methods Employing syngeneic mouse models of head and neck squamous cell carcinoma (cell line SCC VII) and breast cancer (cell line 4T1), cytokine expression (by multiplex ELISA), neutrophil trafficking (by multi-channel in vivo microscopy and flow cytometry), and neutrophil function (in vitro assays) were analyzed. Results Here, we show that signals released during early tumor growth promote excessive biological ageing of circulating neutrophils as indicated by age-related changes in their molecular repertoire. These events facilitate the accumulation of these highly reactive immune cells in malignant lesions and endow them with potent pro-tumorigenic functions. In particular, excessively aged neutrophils release neutrophil elastase which, in turn, stimulates the proliferation of cancer cells. Counteracting accelerated biological ageing of circulating neutrophils by blocking the chemokine receptor CXCR2 effectively suppressed tumor growth. Conclusions Our experimental data uncover a potent self-sustaining mechanism of malignant tumors in fostering pro-tumorigenic phenotypic and functional changes in circulating neutrophils, thus supporting tumor progression. Interference with this aberrant process might provide a novel, already pharmacologically targetable strategy for cancer therapy. This study was supported by Deutsche Forschungsgemeinschaft (DFG), Sonderforschungsbereich (SFB) 914. Disclosure Information C.A. Reichel: None. L. Mittmann: None. J. Schaubächer: None. R. Hennel: None. G. Zuchtriegel: None. M. Canis: None. O. Gires: None. F. Krombach: None. L. Holdt: None. S. Brandau: None. T. Vogl: None. K. Lauber: None. B. Uhl: None.

In advanced inflammatory disease, microvascular thrombosis leads to the interruption of blood supply and provokes ischemic tissue injury. Recently, intravascularly adherent leukocytes have been reported to shape the blood flow in their immediate vascular environment. Whether these rheological effects are relevant for microvascular thrombogenesis remains elusive. Employing multi-channel in vivo microscopy, analyses in microfluidic devices, and computational modeling, we identified a previously unanticipated role of leukocytes for microvascular clot formation in inflamed tissue. For this purpose, neutrophils adhere at distinct sites in the microvasculature where these immune cells effectively promote thrombosis by shaping the rheological environment for platelet aggregation. In contrast to larger (lower-shear) vessels, this process in high-shear microvessels does not require fibrin generation or extracellular trap formation, but involves GPIbα-vWF and CD40-CD40L-dependent platelet interactions. Conversely, interference with these cellular interactions substantially compromises microvascular clotting. Thus, leukocytes shape the rheological environment in the inflamed venular microvasculature for platelet aggregation thereby effectively promoting the formation of blood clots. Targeting this specific crosstalk between the immune system and the hemostatic system might be instrumental for the prevention and treatment of microvascular thromboembolic pathologies, which are inaccessible to invasive revascularization strategies.

There is emerging evidence that neutrophilic granulocytes (neutrophils) substantially contribute to the pathogenesis of head and neck squamous cell carcinoma (HNSCC). The underlying mechanisms, however, remain poorly understood. Recently, the NLRP3 inflammasome has been identified to play a key role for the initiation of inflammatory processes. We therefore hypothesized that this intracellular protein complex is vital for neutrophil trafficking to HNSCC.

Objective Ischemia-reperfusion (I/R) injury significantly contributes to organ dysfunction and failure after myocardial infarction, stroke, and transplantation. In addition to its established role in the fibrinolytic system, plasminogen activator inhibitor-1 has recently been implicated in the pathogenesis of I/R injury. The underlying mechanisms remain largely obscure. Approach and Results Using different in vivo microscopy techniques as well as ex vivo analyses and in vitro assays, we identified that plasminogen activator inhibitor-1 rapidly accumulates on microvascular endothelial cells on I/R enabling this protease inhibitor to exhibit previously unrecognized functional properties by inducing an increase in the affinity of 2 integrins in intravascularly rolling neutrophils. These events are mediated through low-density lipoprotein receptor-related protein-1 and mitogen-activated protein kinase-dependent signaling pathways that initiate intravascular adherence of these immune cells to the microvascular endothelium. Subsequent to this process, extravasating neutrophils disrupt endothelial junctions and promote the postischemic microvascular leakage. Conversely, deficiency of plasminogen activator inhibitor-1 effectively reversed leukocyte infiltration, microvascular dysfunction, and tissue injury on experimental I/R without exhibiting side effects on microvascular hemostasis. Conclusions Our experimental data provide novel insights into the nonfibrinolytic properties of the fibrinolytic system and emphasize plasminogen activator inhibitor-1 as a promising target for the prevention and treatment of I/R injury.

Aim: To optimize the design of nanoparticles for diagnosis or therapy of vascular diseases, it is mandatory to characterize the determinants of nano-bio interactions in vascular lesions. Materials & methods: Using ex vivo and in vivo microscopy, we analyzed the interactive behavior of quantum dots with different surface functionalizations in atherosclerotic lesions of ApoE-deficient mice. Results: We demonstrate that quantum dots with different surface functionalizations exhibit specific interactive behaviors with distinct molecular and cellular components of the injured vessel wall. Moreover, we show a role for fibrinogen in the regulation of the spatio-temporal interaction dynamics in atherosclerotic lesions. Conclusion: Our findings emphasize the relevance of surface chemistry-driven nano-bio interactions on the differential in vivo behavior of nanoparticles in diseased tissue.

Neutrophile Granulozyten werden in zunehmendem Maße als wesentliche Faktoren der Pathogenese von Plattenepithelkarzinomen des Kopf-Hals-Bereiches (HNSCC) angesehen. Die zugrunde liegenden Mechanismen sind jedoch weitgehend ungeklärt. Aufgrund seiner Schlüsselrolle bei Entzündungsvorgängen könnte das NLRP3-Inflammasom wesentlich an der Rekrutierung von neutrophilen Granulozyten zu HNSCC beteiligt sein.

Aim: To assess the role of the endothelial glycocalyx (eGCX) for the uptake of nanoparticles by endothelial cells. Methods: The expression of the eGCX on cultured human umbilical vein endothelial cells was determined by immunostaining of heparan sulfate. Enzymatic degradation of the eGCX was achieved by incubating the cells with eGCX-shedding enzymes. The uptake of 50-nm polystyrene nanospheres was quantified by confocal microscopy. Results: Human umbilical vein endothelial cells expressed a robust eGCX when cultured for 10 days. The uptake of both carboxylated and aminated polystyrene nanospheres was significantly increased in cells in which the glycocalyx was enzymatically degraded, while it remained at a low level in cells with an intact glycocalyx. Conclusion: The eGCX constitutes a barrier against the internalization of blood-borne nanoparticles by endothelial cells.

The biopolymer DNA allows to create nanoscale, biocompatible structures, which can be designed in a target-specific and stimuli-responsive manner. DNA carrier systems with these characteristics hold a great potential for nanomedical applications, such as for the treatment of inflammatory diseases.Here we used a DNA-based drug carrier system for the pH-dependent delivery of the glucocorticoid dexamethasone into macrophages, a cell type with a key role in the regulation of inflammation. Dexamethasone (Dex) nanotubes were internalized within minutes by MH-S macrophages in vitro and by tissue resident macrophages in the mouse cremaster muscle in vivo and localized in their endosomes.Treatment with Dex nanotubes in vitro significantly reduced the LPS-induced TNF secretion by macrophages, as compared to equivalent amounts of free dexamethasone without affecting cell viability. Microinjection of Dex nanotubes into postischemic muscle tissue of anesthetized mice resulted in a marked reduction of ischemia-reperfusion-elicited leukocyte transmigration and diminished vascular expression of the endothelial adhesion molecules VCAM-1 and ICAM-1.Taken together, our results demonstrate that DNA nanotubes can be used as a platform for the targeted delivery of glucocorticoids and could thus foster the development of nanomedical therapeutics with reduced off-target effects. (C) 2017 Elsevier Ltd. All rights reserved.

The death toll associated with inhaled ambient particulate matter (PM) is attributed mainly to cardio-vascular rather than pulmonary effects. However, it is unclear whether the key event for cardiovascular impairment is particle translocation from lung to circulation (direct effect) or indirect effects due to pulmonary particle-cell interactions. In this work, we addressed this issue by exposing healthy mice via inhalation and intra-arterial infusion (IAI) to carbon nanoparticles (CNP) as surrogate for soot, a major constituent of (ultrafine) urban PM.

Advances in the engineering of nanoparticles (NPs), which represent particles of less than 100 nm in one external dimension, led to an increasing utilization of nanomaterials for biomedical purposes. A prerequisite for their use in diagnostic and therapeutic applications, however, is the targeted delivery to the site of injury. Interactions between blood-borne NPs and the vascular endothelium represent a critical step for nanoparticle delivery into diseased tissue. Here, we show that the endothelial glycocalyx, which constitutes a glycoprotein polysaccharide meshwork coating the luminal surface of vessels, effectively controls interactions of carboxyl-functionalized quantum dots with the micro vascular endothelium. Glycosaminoglycans of the endothelial glycocalyx were found to physically cover endothelial adhesion and signaling molecules, thereby preventing endothelial attachment, uptake, and translocation of these nanoparticles through different layers of the vessel wall. Conversely, degradation of the endothelial glycocalyx promoted interactions of these nanoparticles with microvascular endothelial cells under the pathologic condition of ischemia-reperfusion, thus identifying the injured endothelial glycocalyx as an essential element of the blood-tissue border facilitating the targeted delivery of nanomaterials to diseased tissue.