tbuckley/cabot-search huggingface dataset:
Abstract 5672: Deletion of Bone Marrow Derived Receptor for Advanced Glycation End-products (RAGE) Does Not Attenuate Plaque Formation but Inhibits Plaque Progression in a Mouse Model of Advanced Atherosclerosis
Authors: Michael R Preusch, Sam Morris-Rosenfeld, Angelika Bierhaus, Claudia Albrecht, Erwin Blessing, Martin Andrassy, Hugo A Katus, Florian Bea
Journal: Circulation (2009)

Background and Hypothesis: The multiligand receptor for advanced glycation end products (RAGE) of the immunoglobulin superfamily is expressed on multiple cell types implicated in the immune-inflammatory response and in atherosclerosis. We sought to determine the role that bone marrow derived RAGE plays in different stages of atherosclerotic lesion development in apolipoprotein E deficient (apoE −/− ) mice. Methods and Results: 7 and 23 week apoE −/− mice were lethally irradiated and given bone marrow from RAGE null (RAGE −/− //apoE −/− ) or RAGE −/−/ /apoE −/− mice to create double knock out chimeras. After 16 weeks on a standard chow diet the mice were sacrificed and atherosclerotic lesion development was evaluated. Plaques in the aortic root of the young mice showed no significant difference in maximum plaque size (217 470±17 480 μ m 2 for the RAGE −/− //apoE −/− mice compared to 244 764±45 840 μ m 2 ) whereas plaques from the older innominate artery of Rage −/− /apoE −/− mice had significantly smaller maximum plaque area compared to the Rage −/−/ apoE −/− mice (83 384±17 981 μ m 2 compared to 136 041±13604 μ m 2 , p&lt;.05) as well as reduced average necrotic core area (35 582±4 797 μ m 2 compared to 55 604±6 523 μ m 2 , p&lt;.05). Reduced plaque size and more stable plaque morphology was associated with significant decreases in the expression of important atherogenic mediators including VCAM-1, ICAM-1, and MCP-1. Accumulation of the RAGE ligand HMGB-1 was also significantly reduced within the lesions of the Rage −/− /apoE −/− mice. Conclusions: This study demonstrates that bone marrow derived RAGE is an important factor in the progression of atherosclerotic plaque development by causing increased expression of pro-atherosclerotic mediators. It provides evidence that RAGE could be a potential target for clinical treatment of advanced atherosclerosis.
Abstract 5669: Monocytic Cells Are Required for Endothelial Regeneration
Authors: Nikos Werner, Bita Haghighat, Daniel Engel, Christian Kurts, Georg Nickenig, Sven Wassmann
Journal: Circulation (2009)

Background: Circulating endothelial progenitor cells (EPC) contribute to endothelial cell (EC) regeneration and are predictors for cardiovascular events. Systemic treatment with EPC fosters the repair of damaged endothelium. We have shown that transfusion of mononuclear cells (MNC) lead to an even more pronounced regeneration of the endothelium compared to EPC transfusion. Here, we determine the role of monocytic CD11b+ cells in EC regeneration. Methods/Results Re-endothelialization, neointima formation, and endothelial function was determined in wild-type (WT) mice treated with intravenous injections of spleen-derived MNC, CD11b-depleted MNC, CD11b+ cells, or cell-free vehicle after EC denudation. EC regeneration was enhanced and neointima formation reduced after transfusion of total MNC and CD11b+ cells but not after CD11b-depleted cells. We further determined the role of monocytes in a model of a disseminated EC damage. In ApoE−/− mice, transfusion of CD11b+ cells and total MNC but not CD11b-depleted MNCs improved endothelial function. To determine the role of endogenous monocytes on EC repair, mice were treated with clodronate-liposomes (10 μ l/g bw) to deplete monocytes. Re-endothelialization after focal EC denudation was significantly diminished in clodronate-treated compared to vehicle-treated mice. Next, we selectively depleted CD11b+ monocytes and tissue-residual macrophages using CD11b-DTR transgenic mice. Treatment with diphtheria toxin (DT) results in the complete ablation of circulating monocytes/tissue-resident macrophages. DT treatment was performed for 10 days (15ng/g bw). At day 5 post EC damage, the denuded area was significantly larger in DT treated compared to vehicle treated mice. Transfusion of Sca1+ cells significantly enhanced re-endothelialization in vehicle-treated CD11b-DTR mice but not in DT treated mice. Finally, transfusion of CD11b+ cells in CD11b-DTR mice treated with either vehicle or DT resulted in a comparable enhancement of re-endothelialization. Conclusion Here we demonstrate that circulating CD11b+ monocytes contribute to EC regeneration. Depletion of circulating monocytes is associated with a delay in re-endothelialization after EC damage and is not rescued by Sca1+ cells.
Abstract 5659: Heterozygous Mutation in the Carboxyl-Terminal Domain of the Type 2 Bone Morphogenetic Protein Receptor Leads to Ligand-Specific Gain of Function
Authors: Patricio Leyton, Hideyuki Beppu, Paul B Yu, Kenneth D Bloch
Journal: Circulation (2009)

Heterozygous mutations in the gene encoding the bone morphogenetic protein (BMP) type II receptor (BMPR2) are associated with familial and idiopathic pulmonary arterial hypertension. These mutations are found to affect all domains of the protein, including the amino-terminal ligand-binding domain, the intracellular kinase domain, and the long cytoplasmic carboxyl-terminal (CT) domain. Binding of BMP ligands to BMPR2 and BMP type I receptors leads to phosphorylation of SMAD 1, 5, and 8 and expression of genes including Id1. In pulmonary artery smooth muscle cells (PaSMC) isolated from mice with a heterozygous nonsense mutation in the BMPR2 amino-terminal domain (BMPR2 +/− ), BMP4 and BMP7 signaling is reduced, whereas deletion of both BMPR2 alleles paradoxically augments BMP7 signaling. However, the impact of heterozygous mutations in the BMPR2 CT domain on BMP signaling is still unknown. To characterize the function of the BMPR2 CT domain, we generated a mouse (BMPR2 SG/+ ) in which BMPR2 exon 12 (encoding the CT domain) was deleted, and a sequence specifying green fluorescent protein (GFP) was inserted in frame after exon 11, resulting in a BMPR2 s hort form- G FP fusion protein (SG). Using qRT-PCR and primers for exons 4 and 5, similar levels of BMPR2 transcripts were detected in PaSMC isolated from wild-type (WT) and BMPR2 SG/+ mice. In contrast, using primers for exon 12, there was a 50% reduction of BMPR2 transcripts in BMPR2 SG/+ PaSMC. Similarly, immunoblots performed with a CT-specific antibody revealed that WT BMPR2 protein levels were 50% less in BMPR2 SG/+ than in WT PaSMC. SG protein expression was confirmed using an anti-GFP antibody. Induction of SMAD1/5/8 phosphorylation and Id1 gene expression in response to BMP4 (10 ng/ml) did not differ between WT and BMPR2 SG/+ PaSMC. However, the induction of SMAD1/5/8 phosphorylation and Id1 gene expression by BMP7 were both more than 2-fold greater in BMPR2 SG/+ than WT PaSMC. On the other hand, BMPR2 +/− PaSMC had reduced SMAD1/5/8 activation and Id1 transcription in response to both BMP4 and BMP7. In conclusion, our findings suggest that heterozygous mutations in the BMPR2 CT domain may lead to gain of signaling for a subset of BMP ligands, including BMP7.
Abstract 5643 The Erythropoietin Heterodimeric Beta Common Receptor is in a Complex With and Requires VEGFR2 for Downstream Signaling
Authors: Mark Segal, YanPeng Diao, Laura Sautina
Journal: Circulation (2009)

Background: Endothelial progenitor cells (EPC) circulate in the bloodstream and are capable of carrying out endothelial repair. Erythropoietin (EPO) has been shown to have stimulatory effects on EPC. We have previously demonstrated that EPO effects EPC mobility and increases nitric oxide (NO) levels within cells via the heterodimeric beta-common receptor (BCR) and EPO receptor (EPOR). We now test the hypothesis that not only does EPO induction of NO by the BCR/EPOR complex require vascular endothelial growth factor receptor 2(VEGFR2), but VEGFR2 signaling itself requires the BCR. Methods: EPC colonies isolated from human or mice were incubated with various kinase or VEGF inhibitors for 30 minutes prior to treating 50 mU/mL EPO and determining the bioavailable nitric oxide (NO) by DAF-FM-Diacetate. In addition we examined the ability of EPO and VEGF to promote an increase in NO in EPC isolated from the BCR −/− mice. Results: The EPO induced increase in NO could be completely blocked with a VEGFR2 blocking antibody but not by an antibody against VEGF itself. Blocking VEGFR2 also inhibited the EPO mediated increase in transcription of the RNA for endothelial and inducible NO synthase. Interestingly, the increase in NO was not blocked by a JAK-2 kinase inhbitor (Tyrphostin AG-490) confirming that the EPO induced NO effects are independent of the homodimeric EPO receptor-JAK kinase pathway. Most importantly EPC isolated from the BCR−/− mice had no NO stimulation in response to EPO, or VEGF but had a normal NO stimulation in response to bradykinin. We also demonstrate that the VEGFR2 co-immunoprecipitates and colocalizes with the BCR. Conclusion: We conclude that many of the tissue-protective effects of EPO demonstrated in models of ischemic, traumatic, and inflammatory injuries may be occurring through horizontal signaling of BCR with VEGFR2. In addition VEGFR2 signaling requires the expression of the BCR. These findings have profound implications for the potential side effects of EPO.
Abstract 5671: The Effects of Pharmacological PAI-1 Inhibition in Acute and Chronic Rejection in Murine Cardiac Allografts
Authors: Jun-ichi Suzuki, Masahito Ogawa, Susumu Muto, Yoichi Yamaguchi, Akiko Itai, Yasunobu Hirata, Ryozo Nagai, Mitsuaki Isobe
Journal: Circulation (2009)

Backgrounds: Acute rejection and graft arterial disease (GAD) in cardiac transplantation are enhanced by inflammation and thrombus formation. However, little is known about the effect of plasminogen activator inhibitor-1 (PAI-1) in heart transplantation. Thus, the objective was to clarify the role of PAI-1 in the progression of rejection. Methods and Results: Murine hearts were heterotopically transplanted using major mismatch combinations for evaluation of acute rejection and class II mismatch combinations for the GAD. We performed administration of the specific PAI-1 inhibitor (IMD-1622) into murine recipients of cardiac allografts. Nontreated allografts of the major mismatch group were acutely rejected (n=6; 7.3±0.2 days), while the PAI-1 inhibitor prolonged their survival (n=6; 13.7±2.4 days, P &lt; 0.05). Pathologically, severe myocardial cell infiltration (40.8±3.3 %) and fibrosis (44.5±2.8 %) were observed in untreated allografts, the PAI-1 inhibitor attenuated infiltration (25.8±1.9 %, p&lt;0.05) and fibrosis (25.8±3.1 % p&lt;0.05) in the class II mismatch group on day 60. Although severe GAD (luminal occlusion 28.6±6.4 %) was observed in untreated allografts, the PAI-1 inhibitor suppressed the development of neointimal formation (8.1±3.5 %, p&lt;0.05). Immunohistochemically, CD8 and ICAM-1 were enhanced in nontreated allografts, while the PAI-1 inhibitor markedly attenuated expression of these factors. Zymography showed that increased gelatinase activity was observed in the non-treated allograft group, however, the PAI-1 inhibitor decreased the activity. RNAse protection assay revealed that PAI-1 inhibitor suppressed IFN-gamma compared with that of non-treated group. Conclusion: The PAI-1 inhibitor is potent in the suppression of both allograft rejection and arterial disease because they are critically involved in the development of rejection through the suppression of inflammation.
Abstract 5812: A Novel Role of Insulin Degrading Enzyme (IDE) in Atherosclerosis: Studies Using IDE <sup>−/−</sup> Bone Marrow-Derived Cells Show Increased Lesion Development in a Bone Marrow Transplant LDL Receptor <sup>−/−</sup> Mouse Model
Authors: Justin W Caravaggio, Robin MacLaren, Mirela Hasu, Mohamed Thabet, Stewart C Whitman
Journal: Circulation (2009)

Insulin degrading enzyme (IDE) hypofunction has been shown to promote Alzheimer’s disease as well as type II diabetes in humans and animal models, but it is unknown if IDE has a role in atherosclerosis. The scavenger receptor-A (SRA) plays a key role in foam cell formation as well as fatty streak development. Using affinity chromatography we previously identified a novel interaction between SRA and IDE from J774 cytosolic lysate. Utilizing a bone marrow transplant model, we tested the hypothesis that IDE knockout in bone marrow derived cells would increase atherosclerotic lesion severity in C57BL-6 mice on an LDLr −/− background fed a high fat diet. At 8 weeks of age, male and female LDLr −/− recipient mice underwent γ -irradiation to eliminate endogenous bone marrow. Recipient mice were repopulated with bone marrow from either wild type or IDE −/− , aged matched donor mice. Following 6 weeks of recovery, recipient mice were placed on a high fat diet (21% fat &amp; 0.15% cholesterol) for 8 weeks to generate an atherosclerotic phenotype. In vivo results showed a significant increase in aortic arch lesion area in male mice (6-fold increased lesion area in IDE −/− (n=8) vs. WT (n=12), p&lt;0.001) and a corresponding increase in aortic root lesion size (2.5-fold increased lesion area in IDE −/− (n=12) vs. WT (n=12), p&lt;0.05). Total serum cholesterol was increased in male recipients repopulated with IDE −/− vs. WT (p&lt;0.001). In vitro mechanistic studies using IDE −/− bone marrow-derived macrophages have revealed differences in adhesion (3.2-fold increase in non-adherent cells from IDE −/− mice vs. WT, p&lt;0.05) as well as a difference in uptake and esterification of tritium-labeled oleate ( 3 H) into cholesterol ester (2-fold increase in acLDL incorporation of 3 H oleate in IDE −/− cells vs. WT cells). This suggests IDE plays a key role in macrophage function and foam cell formation during lesion development. To conclude, IDE −/− bone marrow-derived cells resulted in significantly greater lesion development when transplanted into LDLr −/− male mice. These results indicate a prominent role for IDE in atherosclerotic lesion formation and suggest that IDE may provide a novel target for therapeutic intervention.
Abstract 5777: SIRT1 Inhibits VSMC Proliferation and Migration Underlying Neointima Formation Following Vascular Injury
Authors: Li Li, Hui-Na Zhang, Hou-Zao Chen, Peng Gao, Qing-Jun Zhang, Ran Zhang, Xiang Lv, De-Pei Liu, Chih-Chuan Liang
Journal: Circulation (2009)

Vascular SMC (VSMC) proliferation and migration are crucial events involved in the pathophys-iology of vascular diseases. SIRT1, a class III histone deacetylase (HDAC), has been implicated in controlling angiogenesis. However, the role of SIRT1 during the response of VSMCs to injury remains unknown. To study the role of SIRT1 in the neointima formation, we generated transgenic mice expressing the human SIRT1 from a minimal SM22α promoter. We demonstrated that in a mouse carotid artery ligation model, SMC-specific overexpression of SIRT1 substantially reduced neointima formation. SIRT1 overexpression inhibited VSMC proliferation and migration, and induced cell cycle arrest at the G1/S transition. Accordingly, overexpression of SIRT1 decreased cyclin D1 and MMP-9 expression at both mRNA and protein level, whereas knockdown of SIRT1 by RNAi resulted in the reverse effect on their protein expression. Moreover, decreased cyclin D1 and MMP-9 expression/activity were observed in injured carotid arteries of SMC-SIRT1 Tg mice. In addition, two components of activator protein-1(AP-1), c-Fos and c-Jun, interacting with and being deacetylated by SIRT1, were involved in the downregulation of cyclin D1 and MMP-9 expression. These findings demonstrate the inhibitive effect of SIRT1 on neointima formation after vascular injury and suggest a potential pharmacological target for prevention of vascular diseases.
Abstract 5818: Uncovering the Role of Circulating Soluble Receptor for Advanced Glycation End Products in Hypertension: Relationships With Albuminuria
Authors: Costas Tsioufis, Kyriakos Dimitriadis, Dimitris Syrseloudis, Costas Thomopoulos, Anastasia Mazaraki, Antigoni Miliou, Skevos Sideris, Elli Stefanadi, Dimitris Tousoulis, Christodoulos Stefanadis
Journal: Circulation (2009)

Introduction: The soluble receptor for advanced glycation end-products (sRAGE) participates in the development and acceleration of atherosclerosis, while albuminuria is an established marker of target organ damage. Hypothesis: Urinary albumin excretion, expressed as the albumin to creatinine ratio (ACR), may be related to sRAGE in essential hypertensives. Methods: Our population consisted of 80 newly diagnosed untreated non-diabetics with stage I to II essential hypertension [48 men, mean age=52 years, office blood pressure (BP)=145/93 mmHg]. According to the ACR values determined as the mean of two non-consecutive morning spot urine samples, the study population was divided into microalbuminurics (n=27) (mean ACR=30–300 mg/g) and normoalbuminurics (n=53) (mean ACR&lt;30 mg/g). Moreover, in all patients venous blood sampling was performed for estimation sRAGE concentrations. Results: Microalbuminurics compared to normoalbuminurics were older (53±6 vs 49±5 years, p&lt;0.05), had higher 24-h systolic BP (140±13 vs 132±12 mmHg, p=0.001), while did not differ regarding sex and metabolic profile (p=NS). Moreover, microalbuminurics compared to normoalbuminurics exhibited lower levels of sRAGE (1011±458 vs 1503±931 pg/ml, p&lt;0.003). In the total population, ACR was positively related to age (r=0.345, p=0.004), body mass index (r=0.217, p&lt;0.003) and 24-h systolic BP (r=0.514, p&lt;0.0001), whereas it was negatively correlated with sRAGE (r= −0.275, p=0.018). Regarding sRAGE, it was associated with body mass index (r= −0.241, p=0.003), waist to hip ratio (r= −0.463, p&lt;0.0001) and 24-h pulse pressure (r= −0.372, p=0.001). Multiple regression analysis revealed that age, 24-h systolic BP and sRAGE were the independent predictors of ACR ( R 2 =0.47, p&lt;0.0001). Furthermore, analysis of covariance showed that sRAGE values were significantly different between groups even after adjustment for confounding factors (p&lt;0.05). Conclusions: In essential hypertension, microalbuminuria is accompanied by attenuated levels of sRAGE, reflecting pronounced vascular dysfunction. Moreover, the close association of sRAGE with ACR, suggests active involvement of sRAGE in atherosclerotic target organ damage progression in non-diabetic essential hypertensives.
Abstract 5801: Experimental Identification of Hypoxia-induced miR-210 Targets
Authors: Pasquale Fasanaro, Simona Greco, Cristina Banfi, Mario Pescatori, Mircea Ivan, Maurizio C Capogrossi, Fabio Martelli
Journal: Circulation (2009)

MicroRNAs (miRNAs) are small non-protein-coding RNAs that are incorporated into the RNA-induced silencing complex (RISC) and inhibit gene expression by regulating the stability and/or the translational efficiency of target mRNAs. Previously, we demonstrated that miR-210 is a key player of endothelial cell (EC) response to hypoxia, modulating EC survival, migration and ability to form capillary like-structures. Moreover, the receptor tyrosine kinase ligand Ephrin-A3 was identified as one functionally relevant target. Since each miRNA regulates hundreds of mRNAs, different approaches were combined to identify new miR-210 targets. Using target prediction softwares, 32 new miR-210 potential targets were identified. The proteomic profiling of miR-210 over-expressing ECs identified 11 proteins that were specifically inhibited by miR-210, either directly or indirectly. Affymetrix based gene expression profiles identified 51 genes that were both down-modulated by miR-210 and de-repressed when miR-210 was blocked. Surprisingly, only few genes identified either by proteomics or transcriptomics were recognized as miR-210 targets by target prediction algorithms. However, a low-stringency pairing research revealed an enrichment for miR-210 putative binding sites, raising the possibility that these genes were targeted via non-canonical recognition sequences. To clarify this issue, miR-210-loaded RISC was purified by immuno-precipitation along with its mRNA targets. The presence of Ephrin-A3 mRNA in the complex validated this approach. We found that 32 potential targets were indeed enriched in miR-210-loaded RISC, and thus can be considered as genuine miR-210 targets. In keeping with these conclusion, we were able to further validate a sub-set of them by 3′UTR-reporter assays. Gene ontology analysis of the targets confirmed the known miR-210 activity in differentiation and cell cycle regulation, highlighting new functions such as involvement in RNA processing, DNA binding, development, membrane trafficking and aminoacid catabolism. In conclusion, we validated a multidisciplinary approach for miRNAs target identification and indicated novel molecular mechanisms underpinning miR-210 role in EC response to hypoxia.
Abstract 5752: Role of MicroRNA-503 in Diabetic Endotheliopathy
Authors: Andrea Caporali, Christine Völlenkle, Rachel Masson, Andrew Baker, Reuven Agami, Pedro Carmona-Saez, Fabio Martelli, Costanza Emanueli
Journal: Circulation (2009)

Diabetes disturbs endothelial function and reparative neovascularisation, thus contributing to limb ischemia. Recently, we showed that the atypical neurotrophin receptor p75 NTR mediates diabetes-determined impairment of reparative neovascularization. Diabetes induces p75 NTR expression in microvascular endothelial cells (ECs) of ischemic limb muscles, thus impairing EC survival and functions. Conversely, p75 NTR inhibition restores proper post-ischemic neovascularization in diabetic mice. Making a step forward into the understanding of the relevance of p75 NTR in diabetic microangiopathy, here we studied whether p75 NTR modulates the expression of microRNAs (miRNAs) in ECs. MiRNAs are small non-coding RNAs that act as endogenous regulators of gene expression, by controlling degradation and/or translational repression of target mRNAs. Using microarray analyses of miRNAs expression in human umbilical vein ECs (HUVECs) transduced with p75 NTR or control (empty vector), we detected that miRNA-503 (miR-503) was consistently induced in p75 NTR -transduced ECs. Moreover, both p75 NTR and miR-503 expression in HUVECs was increased following culture in high glucose to mimic diabetic hyperglycaemia. Furthermore, miR-503 expression was higher in ischemic muscles of diabetic mice in comparisons to non diabetic mice. Lentivirus-mediated overexpression of miR-503 in HUVECs impaired cell proliferation and decreased in vitro capillary-like network formation on matrigel. In order to search for miR-503 target genes, we used the CORNA R package and TargetScan to identify the link between in silico predicted target genes of miR-503 and genes downregulated in the Illumina™ microarray of p75 NTR -transduced HUVECs and of p75 NTR -transduced limb muscles. Functional analysis revealed that several target genes were involved in cell cycle control and angiogenesis. Among this group of genes, we identified CyclinE1, cdc25A and VEGF-A as direct targets of miR-503 in ECs. These results suggest a role of miRNA-503 in diabetes-induced microangiopathy and impaired angiogenesis.