Endothelial Cells Of Neovessels Research Articles

Lenti-viral overexpression of RhoGEF Trio reduces CD8 T cell extravasation into atherosclerotic vein graft lesions in mice

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Rembrandt Institute for Cardiovascular Sciences Background In advanced atherosclerotic plaques, such as vein graft lesions, neovessels grow into the hypoxic plaque. This intraplaque angiogenic neovessels lack proper endothelial cell-cell junctions and are therefore susceptible to extravasation of leukocytes, which results in inflammation and atherosclerosis. T cells are the largest leukocyte subset found in atherosclerotic plaques and are key drivers of inflammation and plaque progression. RhoGEF Trio improves endothelial barrier function by strengthening endothelial cell-cell junctions in vitro, but its effect on T cell transmigration and its therapeutic potential to impede atherogenesis remains unknown. Methods ApoE3*Leiden mice (n=10/group) underwent bypass surgery in which a donor caval vein was interpositioned into the arterial circulation at the site of the right common carotid artery. Immediately post-operatively, a pluronic gel containing either GFP-Lentivirus (LV) (control) or Trio-GFP-LV (Trio) was locally applied around the vein graft to induce local overexpression of Trio. At post-op day 28, vein grafts were harvested and processed for morphometric and compositional analysis of the atherosclerotic lesions. Additionally, CD4 and CD8 T cells were isolated from healthy human donors and used in vitro to assess the role of Trio on trans-endothelial migration over in vitro-cultured HUVECs. Results At post-op day 28, both luminal and neovessel endothelial cells were GFP positive indicating successful transfection. CD8 T cell infiltration into the atherosclerotic plaque was reduced in the Trio group (45%, p=0.0426), whilst plaque size and the number of neovessels were unaffected. Mechanistically, we observed that adherence of CD8, but not CD4 T cells to the endothelial monolayer was reduced in vitro upon transfection with Trio-LV. This resulted in a decrease in the absolute number of transmigrated CD8 T cells (56%, p=0.0197), whilst the number of transmigrated CD4 T cells was unaffected. Interestingly, CD8 T cells exhibited no difference trans-/paracellular diapedesis, whilst for CD4 T cells Trio overexpression induced transcellular, rather than paracellular, transmigration. Conclusions LV transfection of vein grafts by local application of a pluronic gel holds promise a therapeutic strategy to improve bypass surgery outcomes. LV transfection with RhoGEF Trio did reduce CD8 T cell transmigration (in vivo and in vitro), but not CD4 T cell transmigration (in vitro) into the atherosclerotic plaque, whilst plaque size was not affected. Ongoing investigations focus on the effect of Trio on micro-vascular leakage as well as infiltration of other immune cells into the plaque.

The time-dependent expression of FPR2 and ANXA1 in murine deep vein thrombosis model and its relation to thrombus age.

Thrombus age determination in fatal venous thromboembolism cases is an important task for forensic pathologists. In this study, we investigated the time-dependent expressions of formyl peptide receptor 2 (FPR2) and Annexin A1 (ANXA1) in a stasis-induced deep vein thrombosis (DVT) murine model, with the aim of obtaining useful information for thrombus age timing. A total of 75 ICR mice were randomly classified into thrombosis group and control group. In thrombosis group, a DVT model was established by ligating the inferior vena cava (IVC) of mice, and thrombosed IVCs were harvested at 1, 3, 5, 7, 10, 14, and 21days after modeling. In control group, IVCs without thrombosis were taken as control samples. The expressions of FPR2 and ANXA1 during thrombosis were detected using immunohistochemistry and double immunofluorescence staining. Their protein and mRNA levels in the samples were determined by Western blotting and quantitative real-time PCR. The results reveal that FPR2 was predominantly expressed by intrathrombotic neutrophils and macrophages. ANXA1 expression in the thrombi was mainly distributed in neutrophils, endothelial cells of neovessels, and fibroblastic cells. After thrombosis, the expressions of FPR2 and ANXA1 were time-dependently up-regulated. The percentage of FPR2-positive cells and the level of FPR2 protein significantly elevated at 1, 3, 5 and 7 days after IVC ligation as compared to those at 10, 14 and 21 days after ligation (p < 0.05). Moreover, the mRNA level of FPR2 were significantly higher at 5 days than that at the other post-ligation intervals (p < 0.05). Besides, the levels of ANXA1 mRNA and protein peaked at 10 and 14 days after ligation, respectively. A significant increase in the mRNA level of ANXA1 was found at 10 and 14 days as compared with that at the other post-ligation intervals (p < 0.01). Our findings suggest that FPR2 and ANXA1 are promising as useful markers for age estimation of venous thrombi.

Low-Intensity Focused Ultrasound-Responsive Ferrite-Encapsulated Nanoparticles for Atherosclerotic Plaque Neovascularization Theranostics.

Pathological angiogenesis is a crucial factor that causes atherosclerotic plaque rupture. Sinoporphyrin sodium‐mediated sonodynamic therapy (DVDMS‐SDT) induces regression of plaque neovascularization in humans without causing obvious side effects. However, a clinical noninvasive theranostic strategy for atherosclerotic plaque neovascularization is urgently needed. A nanoplatform designed for multimodality imaging‐guided SDT in plaque angiogenesis theranostics, termed PFP–HMME@PLGA/MnFe2O4–ramucirumab nanoparticles (PHPMR NPs), is fabricated. It encapsulates manganese ferrite (MnFe2O4), hematoporphyrin monomethyl ether (HMME), and perfluoropentane (PFP) stabilized by polylactic acid‐glycolic acid (PLGA) shells and is conjugated to an anti‐VEGFR‐2 antibody. With excellent magnetic resonance imaging (MRI)/photoacoustic/ultrasound imaging ability, the distribution of PHPMR NPs in plaque can be observed in real time. Additionally, they actively accumulate in the mitochondria of rabbit aortic endothelial cells (RAECs), and the PHPMR NP‐mediated SDT promotes mitochondrial‐caspase apoptosis via the production of reactive oxygen species and inhibits the proliferation, migration, and tubulogenesis of RAECs. On day 3, PHPMR NP‐mediated SDT induces apoptosis in neovessel endothelial cells and improves hypoxia in the rabbit advanced plaque. On day 28, PHPMR NP‐mediated SDT reduces the density of neovessels, subsequently inhibiting intraplaque hemorrhage and inflammation and eventually stabilizing the plaque. Collectively, PHPMR NP‐mediated SDT presents a safe and effective theranostic strategy for inhibiting plaque angiogenesis.

De novo Vessel Formation Through Cross-Talk of Blood-Derived Cells and Mesenchymal Stromal Cells in the Absence of Pre-existing Vascular Structures.

BackgroundThe generation of functional blood vessels remains a key challenge for regenerative medicine. Optimized in vitro culture set-ups mimicking the in vivo perivascular niche environment during tissue repair may provide information about the biological function and contribution of progenitor cells to postnatal vasculogenesis, thereby enhancing their therapeutic potential.AimWe established a fibrin-based xeno-free human 3D in vitro vascular niche model to study the interaction of mesenchymal stromal cells (MSC) with peripheral blood mononuclear cells (PBMC) including circulating progenitor cells in the absence of endothelial cells (EC), and to investigate the contribution of this cross-talk to neo-vessel formation.Materials and MethodsBone marrow-derived MSC were co-cultured with whole PBMC, enriched monocytes (Mo), enriched T cells, and Mo together with T cells, respectively, obtained from leukocyte reduction chambers generated during the process of single-donor platelet apheresis. Cells were embedded in 3D fibrin matrices, using exclusively human-derived culture components without external growth factors. Cytokine secretion was analyzed in supernatants of 3D cultures by cytokine array, vascular endothelial growth factor (VEGF) secretion was quantified by ELISA. Cellular and structural re-arrangements were characterized by immunofluorescence and confocal laser-scanning microscopy of topographically intact 3D fibrin gels.Results3D co-cultures of MSC with PBMC, and enriched Mo together with enriched T cells, respectively, generated, within 2 weeks, complex CD31+/CD34+ vascular structures, surrounded by basement membrane collagen type-IV+ cells and matrix, in association with increased VEGF secretion. PBMC contained CD31+CD34+CD45dimCD14– progenitor-type cells, and EC of neo-vessels were PBMC-derived. Vascular structures showed intraluminal CD45+ cells that underwent apoptosis thereby creating a lumen. Cross-talk of MSC with enriched Mo provided a pro-angiogenic paracrine environment. MSC co-cultured with enriched T cells formed “cell-in-cell” structures generated through internalization of T cells by CD31+CD45dim⁣/– cells. No vascular structures were detected in co-cultures of MSC with either Mo or T cells.ConclusionOur xeno-free 3D in vitro vascular niche model demonstrates that a complex synergistic network of cellular, extracellular and paracrine cross-talk can contribute to de novo vascular development through self-organization via co-operation of immune cells with blood-derived progenitor cells and MSC, and thereby may open a new perspective for advanced vascular tissue engineering in regenerative medicine.

For the Success of Oncolytic Viruses: Single Cycle Cures or Repeat Treatments? (One Cycle Should Be Enough).

For the Success of Oncolytic Viruses: Single Cycle Cures or Repeat Treatments? (One Cycle Should Be Enough).

Basic research: Where do new endothelial cells come from in the injured heart?

Revascularization of ischaemia-injured myocardium is critical for functional recovery. A new study shows that endothelial cells of neovessels in the injured heart derive from pre-existing endothelial cells. This new finding focuses research on therapeutic strategies to direct the neovasculature to deliver oxygen and nutrients effectively to the ischaemic myocardium.

Expression of co-stimulatory molecule B7-H4 in patients suffering from rheumatoid arthritis

B7-H4, an inhibitory modulator of T-cell response, is one of the most recently identified cell surface molecules in the B7-CD28 signaling pathway. However, its role in the pathogenesis of rheumatoid arthritis (RA) remains unclear. In the present study, the immunofluorescence staining, confocal laser scanning microscopy and flow cytometry techniques were used to characterize B7-H4 protein expression in RA synovium tissues and peripheral blood mononuclear cell (PBMC) subsets, respectively. Our data showed that the immunolocalization of B7-H4 could be found on the membrane and in the cytoplasm of synoviocytes and CD19+ B cells in rheumatoid synovium tissues, while B7-H4 was weakly or negatively expressed on CD3+ T cells, CD14+ monocytes and CD68+ macrophages. Moreover, B7-H4 expression was observed in CD34+ endothelial cells of neovessels in rheumatoid synovium. Flow cytometric analysis also showed that positive B7-H4 expression was found in CD19+ B cells and CD14+ monocytes, but not in CD3+ T cells. Thus, our work identified the expression pattern of B7-H4 in the synovium tissues and PBMC subsets from RA patients, suggesting that B7-H4 involves in the pathological changes of rheumatoid synovium in RA progression, and its detailed biological function needs further investigations.

Tissue factor expression in rheumatoid synovium: a potential role in pannus invasion of rheumatoid arthritis

Angiogenesis, as well as pannus formation within the joint, plays an important role in the erosion of articular cartilage and bone in the pathological process of rheumatoid arthritis (RA). Tissue factor (TF), an essential initiator of the extrinsic pathway of blood coagulation, is also involved in the angiogenesis and the pannus formation of RA progression. In the present study, we used immunofluorescence and confocal scanning methods to characterize TF immunolocalization in RA synovium. We showed that positive staining of TF could be immunolocalized in synoviocytes, CD19+ B cells and CD68+ macrophages, whereas weak or negative staining of tissue factor could be found in CD34+ endothelial cells of neo-vessels, CD3+ T cells and CD14+ monocytes in RA synovium tissues. Our study demonstrates a detailed local expression of TF in the rheumatoid synovium, and supports the notion that TF, expressed not only by the synoviocytes themselves, but also the infiltrating CD19+ B cells and CD68+ macrophages, is involved in the pannus invasion in the progression of rheumatoid arthritis.

O74. Comparison of the angiogenic marker expression and diffuse reflectance spectroscopy findings on angiogenic patterns in oral squamous cell carcinoma

Angiogenesis, as well as pannus formation within the joint, plays an important role in the erosion of articular cartilage and bone in the pathological process of rheumatoid arthritis (RA). Tissue factor (TF), an essential initiator of the extrinsic pathway of blood coagulation, is also involved in the angiogenesis and the pannus formation of RA progression. In the present study, we used immunofluorescence and confocal scanning methods to characterize TF immunolocalization in RA synovium. We showed that positive staining of TF could be immunolocalized in synoviocytes, CD19+ B cells and CD68+ macrophages, whereas weak or negative staining of tissue factor could be found in CD34+ endothelial cells of neo-vessels, CD3+ T cells and CD14+ monocytes in RA synovium tissues. Our study demonstrates a detailed local expression of TF in the rheumatoid synovium, and supports the notion that TF, expressed not only by the synoviocytes themselves, but also the infiltrating CD19+ B cells and CD68+ macrophages, is involved in the pannus invasion in the progression of rheumatoid arthritis.

Intraoperative fluorescence imaging of peritoneal dissemination of ovarian carcinomas. A preclinical study

Objective Improvement of the management and outcome of ovarian cancers may require intraoperative detection and therapeutic intervention to treat minimal residual disease after complete surgery. The aim of this study was to validate the importance of fluorescence in the peroperative detection of human ovarian adenocarcinoma cells and to determine its efficiency in detecting infra millimetric tumor metastases. Methods A fluorescent RAFT-(cRGD) 4 tracer molecule (AngioStamp®) was used. The tracer is based on a biomarker, which has a very high affinity for the α vβ 3 integrin, which is overexpressed in a large ratio of cancer cells and neovessel endothelial cells during angiogenesis. Infrared fluorescence was visualized with Fluobeam®, an open fluorescent imaging system that could potentially be used in peroperative conditions in the future. Results This novel technique allowed the specific detection of residual tumor deposits and inframillimetric metastases, smaller than 500 μm, which were resected under fluorescent guidance. AngioStamp® was able to detect all types of cell lines, derived from human ovarian adenocarcinomas, before or after chemotherapy treatment in animals. The effectiveness of AngioStamp® for the detection of various human ovarian adenocarcinomas was assessed on 10 different fragments of tumor, implanted subcutaneously in nude mice. All implanted tumor fragments were visualized by AngioStamp®. Conclusions The high rate of recurrence after apparently complete surgery and/or complete clinical response to chemotherapy implies that most patients have undetected minimal residual disease. Novel techniques such as laparoscopic or laparotomic fluorescence may prove to be crucial in reassessing the definition of primary outcome in ovarian cancer management.

Carbonic anhydrase VII–a potential prognostic marker in gliomas

Carbonic anhydrase VII (CA VII) is a cytosolic enzyme expressed in several organs, including the human brain, but it has not been investigated earlier in any tumors. We designed the present study to evaluate CA VII expression in a cohort of human diffuse astrocytomas, mixed oligoastrocytomas and oligodendrogliomas. CA VII immunostaining was correlated to clinico-pathologic findings, survival data, and expres-sion of other molecular factors, including Ki-67, p53 protein and epidermal growth factor receptor. CA VII-positive staining was observed in 94% of astrocytomas and 85% of oligodendrogliomas. In the tumor specimens, strong positive areas were often located in close proximity to necrosis. The CA VII immunoreactivity showed positive correlation with tumor malignancy grades of astrocytomas (p = 0.02, chi-square test). In all tumor categories, CA VII-positive staining was often seen in the en-dothelial cells of neovessels in addition to the tumor cells. CA VII intensity showed no significant association with p53 nor did it correlate with the amplification of epidermal growth factor receptor (analyzed only in astrocytomas) or cell proliferation. Our present results show that CA VII may act as a useful biomarker in histopathologic diagnostics of gliomas. The high expression of CA VII in the tumor cells and endothelium suggests important roles for the enzyme in tumor metabolism. The results also led us to conclude that CA VII might serve as a marker of poor prognosis in diffuse astrocytomas.

Heparanase expression of glioma in human and animal models

Mammalian heparanase has been shown to function in tumor progression, invasion, and angiogenesis. However, heparanase expression in gliomas has not been well analyzed. To clarify its expression in gliomas, human glioma tissues and glioma animal models were investigated. The expression of heparanase mRNA was determined in 33 resected human glioma tissues by semiquantitative real-time polymerase chain reaction. Heparanase expression was verified with a Western blot assay and immunohistochemistry (IHC) staining. Primary neurospheres from human glioblastoma multiforme (GBM) were developed in vitro. Heparanase expression in murine astrocytoma and human primary neurosphere animal models was examined using IHC. The authors found that heparanase mRNA is greatly increased in gliomas including oligodendroglioma (9 samples), anaplastic astrocytoma (11 samples), and GBM (13 samples) as compared with healthy brain mRNA (3 samples). Note, however, that no significant difference was observed among the 3 tumor groups. Increased heparanase expression was also found in tumor tissues on Western blotting. Immunohistochemistry staining demonstrated that heparanase was expressed by neovessel endothelial cells, infiltrated neutrophils, and in some cases, by neoplastic cells. Heparanase-expressing cells, including GBM tumor cells and neovessel endothelial cells, exhibited decreased expression of CD44, a cell adhesion molecule on the cell membrane that is important for regulating tumor invasion. In addition, heparanase-expressing tumor cells showed an elevated density of the cell proliferation marker Ki 67, as compared with its density in non-heparanase-expressing tumor cells, suggesting that heparanase expression is correlated with enhanced tumor proliferation. Two animal glioma models were tested for heparanase expression. Both murine astrocytoma cells (Ast11.9-2) and cultured primary human GBM neurospheres expressed heparanase when grown in animal brain tissue. Glioma tissues contain increased levels of heparanase. Multiple cell types contribute to the expression of heparanase, including neovessel endothelial cells, tumor cells, and infiltrated neutrophils. Heparanase plays an important role in the control of cell proliferation and invasion. Animal models using Ast11.9-2 and primary neurospheres are suitable for antitumor studies targeting heparanase.

Intravascularly Administered RGD-Displaying Measles Viruses Bind to and Infect Neovessel Endothelial Cells In Vivo

Systemically administered vectors must cross the endothelial lining of tumor blood vessels to access cancer cells. Vectors that interact with markers on the lumenal surface of these endothelial cells might have enhanced tumor localization. Here, we generated oncolytic measles viruses (MVs) displaying alpha(v)beta(3) integrin-binding peptides, cyclic arginine-glycine-aspartate (RGD) or echistatin, on the measles hemagglutinin protein. Both viruses had expanded tropisms, and efficiently entered target cells via binding to integrins, but also retained their native tropisms for CD46 and signaling lymphocyte activation molecule (SLAM). When fluorescently labeled and injected intravascularly into chick chorioallantoic membranes (CAMs), in contrast to unmodified viruses, the integrin-binding viral particles bound to the lumenal surface of the developing chick neovessels and infected the CAM vascular endothelial cells. In a mouse model of VEGF-induced angiogenesis in the ear pinna, the integrin-binding viruses, but not the parental virus, infected cells at sites of new blood vessel formation. When given intravenously to mice bearing tumor xenografts, the integrin-binding virus infected endothelial cells of tumor neovessels in addition to tumor parenchyma. To our knowledge, this is the first report demonstrating that oncolytic MVs can be engineered to target the lumenal endothelial surface of newly formed blood vessels when administered intravenously in living animals.

Down Syndrome Candidate Region 1,a Downstream Target of VEGF, Participa tes in Endothelial Cell Migration and Angiogenesis

Vascular endothelial growth factor (VEGF) is a principal stimulator of angiogenesis. However, the downstream targets of VEGF in endothelial cells (ECs) are not entirely clarified. Survey of downstream targets of VEGF in human ECs identified a number of genes, including Down syndrome candidate region 1 (DSCR1). Here, we confirmed the inducible expression of DSCR1 in ECs by Northern and Western blottings. Moreover, VEGF-stimulated induction of DSCR1 was blocked by anti-VEGF receptor-2 monoclonal antibody (mAb), or the specific calcineurin inhibitors cyclosporin A and FK506. The expression of DSCR1 in ECs of neovessels was further shown by immunohistochemical analysis. We therefore examined whether DSCR1 played any roles in angiogenesis. The specific downregulation of DSCR1 expression by antisense oligonucleotide (AS-ODN) inhibited VEGF-stimulated migration of ECs as well as angiogenesis in vivo. AS-ODN inhibited the spreading of ECs on vitronectin, as well as on the immobilized anti-αvβ3 mAb, but not on anti-αvβ5 mAb. Moreover, AS-ODN inhibited tyrosine phosphorylation of focal adhesion kinase when ECs were plated on a vitronectin-coated dish. Immunoprecipitation followed by Western blotting showed the coimmunoprecipitation of DSCR1 and integrin αvβ3. These results suggest that DSCR1 is involved in angiogenesis by regulating adhesion and migration of ECs via the interaction with integrin αvβ3.

SPARC: a signal of astrocytic neoplastic transformation and reactive response in human primary and xenograft gliomas.

In an attempt to identify genetic alterations occurring early in astrocytoma progression, we performed subtractive hybridization between astrocytoma and glioblastoma cDNA libraries. We identified secreted protein acidic and rich in cysteine (SPARC), a protein implicated in cell-matrix interactions, as a gene overexpressed early in progression. Northern blot and immunohistochemical analyses indicated that transcript and protein were both elevated in all tumor specimens (grades II-IV) examined when compared with levels in normal brain. The level of SPARC expression was found to be tumor-dependent rather than grade-related. Immunohistochemically, SPARC protein was found to be overexpressed in 1) cells in the less cellularly dense regions within the tumor mass, 2) histomorphologically neoplastic-looking cells in adjacent normal brain at the tumor/brain interface, 3) neovessel endothelial cells in both the tumor and adjacent normal brain, and 4) reactive astrocytes in normal brain adjacent to tumor. Using a combination of DNA in situ hybridization and protein immunohistochemical analyses of the human/rat xenograft, SPARC expression was observed in the human glioma cells within the tumor mass, and in cells that invaded along vascular basement membranes and individually into the rat brain parenchyma, suggesting it may be an invasion-related gene. While it remains to be determined whether SPARC functionally contributes to tumor cell invasion, these data suggest that the early onset of increased SPARC expression, though complex, may serve as a signal indicative of neoplastic astrocytic transformation and reactive response to tumor-induced stress.