Purpose: To demonstrate polarization sensitive (PS) optical coherence tomography (OCT) for non-invasive, volumetric, and quantitative imaging of the birefringent properties of the peripapillary rat sclera. To compare the findings in PS-OCT images to state-of-the-art histomorphometric analysis of the same tissues. Methods: A high-speed PS-OCT prototype operating at 840 nm was modified for imaging the rat eye. Densely sampled PS-OCT raster scans covering an area of ~1.5 mm × 1.5 mm centered at the papilla were acquired in the eyes of anesthetized, male Sprague Dawley rats. Cross-sectional PS-OCT images were computed and fundus maps displaying the birefringent properties of the sclera were analyzed. Post mortem histomorphological analysis was performed. Results: PS-OCT enables the visualization of the polarization properties of ocular tissues in vivo. The birefringent characteristics of the rat sclera were quantitatively assessed. Scleral birefringence formed a donut shaped pattern around the papilla with significantly increased values of 0.703 ± 0.089°/µm (i.e., 1.64×10(-3) ± 0.2×10(-3); mean ± standard deviation) and 0.721 ± 0.084°/µm (i.e., 1.68×10(-3) ± 0.2×10(-3)) at an eccentricity of 0.4 mm for the left and right eyes, respectively. Birefringent axis orientation maps revealed a ring-shaped distribution around the optic nerve. Post mortem PS-OCT micrographs provided access to retinal and scleral microstructure and were compared to standard histomorphological analysis. Conclusion: PS-OCT enables quantitative imaging of tissue polarization properties in addition to conventional OCT imaging based on reflectivity. In the rat sclera, in vivo PS-OCT provides access to volumetric mapping of birefringence. Scleral birefringence is associated with microstructural tissue organization. Therefore, PS-OCT should prove a valuable tool for the in vivo investigation of peripapillary sclera in glaucoma.
Whereas the role of the G-protein-coupled APJ receptor and its ligand, apelin, in angiogenesis has been well documented, the ability of the apelin/APJ system to induce lymphangiogenesis and lymphatic metastasis has been largely unexplored. To this end, we first show that APJ is expressed in lymphatic endothelial cells (LECs) and, moreover, that it responds to apelin by activating the apelinergic signaling cascade. We find that although apelin treatment does not influence the proliferation of LECs in vitro, it enhances their migration, protects them against UV irradiation-induced apoptosis, increases their spheroid numbers in 3D culture, stimulates their in vitro capillary-like tube formation and, furthermore, promotes the invasive growth of lymphatic microvessels in vivo in the matrigel plug assay. We also demonstrate that apelin overexpression in malignant cells is associated with accelerated in vivo tumor growth and with increased intratumoral lymphangiogenesis and lymph node metastasis. These results indicate that apelin induces lymphangiogenesis and, accordingly, plays an important role in lymphatic tumor progression. Our study does not only reveal apelin as a novel lymphangiogenic factor but might also open the door for the development of novel anticancer therapies targeting lymphangiogenesis.
Hippocampal long term potentiation (LTP), representing a cellular model for learning and memory formation, can be dissociated into at least two phases: a protein-synthesis-independent early phase, lasting about 4h and a protein-synthesis-dependent late phase LTP lasting 6h or longer, or even days. A large series of protein kinases have been shown to be involved and herein, a distinct set of protein kinases proposed to be involved in memory retrieval in previous work was tested in dorsal hippocampus of the rat following induction of late-phase LTP. A bipolar stimulation electrode was chronically implanted into the perforant path, while two monopolar recording electrodes were implanted into the dentate gyrus of the dorsal hippocampus. The recording electrode was measuring extracellular excitatory postsynaptic potentials, while the other one measured population spikes. Protein kinases were determined by immunoblotting and immunoflourescence on hippocampal areas showed the distribution pattern of protein kinases PKN1 and NEK7. Induction of LTP was proven, elevated levels for protein kinases PKN1, RPS6KB1, STK4, CDC42BPB, PRKG, TLK, BMX and decreased levels for NEK7, MAK14 and PLK1 were observed. A remarkable overlap of protein kinases observed in spatial memory processes with those proposed in LTP formation was demonstrated. The findings may be relevant for design of future studies on protein kinases and for the interpretation of previous work.
Increased visceral fat is associated with a high risk of diabetes and metabolic syndrome and is in part caused by excessive glucocorticoids (GCs). However, the molecular mechanisms remain undefined. We now identify the GC-dependent gene LIM domain only 3 (LMO3) as being selectively upregulated in a depot-specific manner in human obese visceral adipose tissue, localizing primarily in the adipocyte fraction. Visceral LMO3 levels were tightly correlated with expression of 11?-hydroxysteroid dehydrogenase type-1 (HSD11B1), the enzyme responsible for local activation of GCs. In early human adipose stromal cell differentiation, GCs induced LMO3 via the GC receptor and a positive feedback mechanism involving 11?HSD1. No such induction was observed in murine adipogenesis. LMO3 overexpression promoted, while silencing of LMO3 suppressed, adipogenesis via regulation of the proadipogenic PPAR? axis. These results establish LMO3 as a regulator of human adipogenesis and could contribute a mechanism resulting in visceral-fat accumulation in obesity due to excess glucocorticoids.
Interleukin-33 (IL-33) is a recently described member of the IL-1 family of cytokines, which was identified as a ligand for the ST2 receptor. Components of the IL-33/ST2 system were shown to be expressed in normal and pressure overloaded human myocardium, and soluble ST2 (sST2) has emerged as a prognostic biomarker in myocardial infarction and heart failure. However, expression and regulation of IL-33 in human adult cardiac myocytes and fibroblasts was not tested before. In this study we found that primary human adult cardiac fibroblasts (HACF) and human adult cardiac myocytes (HACM) constitutively express nuclear IL-33 that is released during cell necrosis. Tumor necrosis factor (TNF)-?, interferon (IFN)-? and IL-1? significantly increased both IL-33 protein and IL-33 mRNA expression in HACF and HACM as well as in human coronary artery smooth muscle cells (HCASMC). The nuclear factor-?B (NF-?B) inhibitor dimethylfumarate inhibited TNF-?- and IL-1?-induced IL-33 production as well as nuclear translocation of p50 and p65 NF-?B subunits in these cells. Mitogen-activated protein/extracellular signal-regulated kinase inhibitor U0126 abrogated TNF-?-, IFN-?-, and IL-1?-induced and Janus-activated kinase inhibitor I reduced IFN-?-induced IL-33 production. We detected IL-33 mRNA in human myocardial tissue from patients undergoing heart transplantation (n=27) where IL-33 mRNA levels statistically significant correlated with IFN-? (r=0.591, p=0.001) and TNF-? (r=0.408, p=0.035) mRNA expression. Endothelial cells in human heart expressed IL-33 as well as ST2 protein. We also reveal that human cardiac and vascular cells have different distribution patterns of ST2 isoforms (sST2 and transmembrane ST2L) mRNA expression and produce different amounts of sST2 protein. Both human macrovascular (aortic and coronary artery) and heart microvascular endothelial cells express specific mRNA for both ST2 isoforms (ST2L and sST2) and are a source for sST2 protein, whereas cardiac myocytes, cardiac fibroblasts and vascular SMC express only minor amounts of ST2 mRNA and do not secrete detectable amounts of sST2 antigen. In accordance with the cellular distribution of ST2 receptor, human cardiac fibroblasts and myocytes as well as HCASMC did not respond to treatment with IL-33, as recombinant human IL-33 did not induce NF-?B p50 and p65 subunits nuclear translocation or increase IL-6, IL-8, and monocyte chemoattractant protein (MCP-1) level in HACF, HACM and HCASMC. In summary, we found that endothelial cells seem to be the source of sST2 and the target for IL-33 in the cardiovascular system. IL-33 is expressed in the nucleus of human adult cardiac fibroblasts and myocytes and released during necrosis. Proinflammatory cytokines TNF-?, IFN-? and IL-1? increase IL-33 in these cells in vitro, and IL-33 mRNA levels correlated with TNF-? and IFN-? mRNA expression in human myocardial tissue.
A high throughput method based on flow injection analysis was developed and validated for the quantification of the peptide B?(15-42) in cellular samples comparing different labeling strategies and detection methods. The used labels were 1,4,7,10-tetraazacyclododecane-N, N, N, N-tetraaceticacid (In-DOTA) and 2-(4-isothiocyanatobenzyl) - 1,4,7,10-tetraazacyclododecane-N, N, N, N-tetraacetic acid (In-DOTA-Bn) for elemental labeling. 6-Hydroxy-9-(2-carboxyphenyl)- (3H)-xanthen-3-on (fluorescein) was employed as fluorescence label. The explored peptide (mass = 3 kD) is a novel candidate drug, which shows an anti-inflammatory effect after an event of myocardial infarction. The analysed samples were fractioned cell compartments of human umbilical cord vein endothelial cells (HUVEC) maintained via lysis with Triton X buffer. In order to enhance sensitivity and selectivity of peptide quantification via flow injection the peptide was labeled prior to incubation using elemental and fluorescence labels. Quantification of the elemental and fluorescence labeled peptide was performed via flow injection analysis combined with inductive coupled plasma sector field mass spectrometry (FIA-ICP-SFMS) or fluorescence detection (FIA-FLD), respectively. The employed quantification strategies were external calibration in the case of fluorescence detection and external calibration with and without internal standardization and on-line IDMS in the case of ICP-MS detectionThe limit of detection (LOD) for FIA-ICP-MS was 9 pM In-DOTA-B?(15-42) (0.05 fmol absolute) whereas FIA-FLD showed a LOD of 100 pM (3 fmol absolute) for the fluorescein labeled peptide. Short term precision of FIA-ICP-MS was superior for all ICP-MS based quantification strategies compared to FIA-FLD (FIA-ICP-SFMS: 0.3-3.3%; FIA-FLD: 6.5%). Concerning long term precision FIA-ICP-SFMS with on-line IDMS and internal standardization showed the best results (3.1 and 4.6%, respectively) whereas the external calibration of both applied methodological approaches was only in the range of 10 %.The concentrations in the Triton X soluble fraction relative to the applied amount of Indium in the cell culture were in the range of 0.75-1.8% for In-DOTA or 0.30-0.79% for the 2-(4-isothiocyanatobenzyl) - 1,4,7,10-tetraazacyclododecane-N, N, N, N-tetraacetic acid (In-DOTA-Bn) labeled peptide B?(15-42). In the Triton X insoluble fraction the relative concentrations of Indium were 0.03-0.18% for the In-DOTA labeled peptide and 0.03-0.13% for B?(15-42)-In-DOTA-Bn.
Interleukin (IL)-33 is the most recently described member of the IL-1 family of cytokines and it is a ligand of the ST2 receptor. While the effects of IL-33 on the immune system have been extensively studied, the properties of this cytokine in the cardiovascular system are much less investigated. Methods/Results- We show here that IL-33 promoted the adhesion of human leukocytes to monolayers of human endothelial cells and robustly increased vascular cell adhesion molecule-1, intercellular adhesion molecule-1, endothelial selectin, and monocyte chemoattractant protein-1 protein production and mRNA expression in human coronary artery and human umbilical vein endothelial cells in vitro as well as in human explanted atherosclerotic plaques ex vivo. ST2-fusion protein, but not IL-1 receptor antagonist, abolished these effects. IL-33 induced translocation of nuclear factor-?B p50 and p65 subunits to the nucleus in human coronary artery endothelial cells and human umbilical vein endothelial cells and overexpression of dominant negative form of I?B kinase 2 or I?B? in human umbilical vein endothelial cells abolished IL-33-induced adhesion molecules and monocyte chemoattractant protein-1 mRNA expression. We detected IL-33 and ST2 on both protein and mRNA level in human carotid atherosclerotic plaques.
Supervised exercise training (SET) is recommended as initial treatment to improve walking capacity in peripheral arterial disease (PAD) patients with intermittent claudication. Various mechanisms by which SET yields beneficial effects are postulated, however data regarding its influence on angiogenesis are scarce. Thus, we designed a prospective randomized controlled trial to study the impact of SET on markers of angiogenesis and endothelial function in PAD.
Systemic mastocytosis is a neoplastic disease of mast cells harboring the activating KIT mutation D816V. In most patients, mast cell infiltration in the bone marrow is accompanied by marked microenvironment alterations, including increased angiogenesis, osteosclerosis, and sometimes fibrosis. Little is known about the mast cell-derived molecules contributing to these bone marrow alterations. We show here that neoplastic mast cells in patients with systemic mastocytosis express oncostatin M (OSM), a profibrogenic and angiogenic modulator. To study the regulation of OSM expression, KIT D816V was inducibly expressed in Ba/F3 cells and was found to up-regulate OSM mRNA and protein levels, suggesting that OSM is a KIT D816V-dependent mediator. Correspondingly, KIT D816V(+) HMC-1.2 cells expressed significantly higher amounts of OSM than the KIT D816V(-) HMC-1.1 subclone. RNA interference-induced knockdown of STAT5, a key transcription factor in KIT D816V(+) mast cells, inhibited OSM expression in HMC-1 cells, whereas a constitutively activated STAT5 mutant induced OSM expression. Finally, OSM secreted from KIT D816V(+) mast cells stimulated growth of endothelial cells, fibroblasts, and osteoblasts, suggesting that mast cell-derived OSM may serve as a key modulator of the marrow microenvironment and thus contribute to the pathology of systemic mastocytosis.
Loss of vascular barrier function causes leak of fluid and proteins into tissues, extensive leak leads to shock and death. Barriers are largely formed by endothelial cell-cell contacts built up by VE-cadherin and are under the control of RhoGTPases. Here we show that a natural plasmin digest product of fibrin, peptide Bbeta15-42 (also called FX06), significantly reduces vascular leak and mortality in animal models for Dengue shock syndrome. The ability of Bbeta15-42 to preserve endothelial barriers is confirmed in rats i.v.-injected with LPS. In endothelial cells, Bbeta15-42 prevents thrombin-induced stress fiber formation, myosin light chain phosphorylation and RhoA activation. The molecular key for the protective effect of Bbeta15-42 is the src kinase Fyn, which associates with VE-cadherin-containing junctions. Following exposure to Bbeta15-42 Fyn dissociates from VE-cadherin and associates with p190RhoGAP, a known antagonists of RhoA activation. The role of Fyn in transducing effects of Bbeta15-42 is confirmed in Fyn(-/-) mice, where the peptide is unable to reduce LPS-induced lung edema, whereas in wild type littermates the peptide significantly reduces leak. Our results demonstrate a novel function for Bbeta15-42. Formerly mainly considered as a degradation product occurring after fibrin inactivation, it has now to be considered as a signaling molecule. It stabilizes endothelial barriers and thus could be an attractive adjuvant in the treatment of shock.
Alterations in epidermal growth factor (EGF) expression are known to be of prognostic relevance in human melanoma, but EGF-mediated effects on melanoma have not been extensively studied. As lymph node metastasis usually represents the first major step in melanoma progression, we were trying to identify a potential role of primary tumor-derived EGF in the mediation of melanoma lymph node metastases. Stable EGF knockdown (EGFkd) in EGF-high (M24met) and EGF-low (A375) expressing melanoma cells was generated. Only in EGF-high melanoma cells, EGFkd led to a significant reduction of lymph node metastasis and primary tumor lymphangiogenesis in vivo, as well as impairment of tumor cell migration in vitro. Moreover, EGF-induced sprouting of lymphatic but not of blood endothelial cells was abolished using supernatants of M24met EGFkd cells. In addition, M24met EGFkd tumors showed reduced vascular endothelial growth factor-C (VEGF-C) expression levels. Similarly, in human primary melanomas, a direct correlation between EGF/VEGF-C and EGF/Prox-1 expression levels was found. Finally, melanoma patients with lymph node micrometastases undergoing sentinel node biopsy were found to have significantly elevated EGF serum levels as compared with sentinel lymph node-negative patients. Our data indicate that tumor-derived EGF is important in mediating melanoma lymph node metastasis.
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