Leukocyte recruitment to sites of infection or inflammation requires multiple adhesive events. While numerous players promoting leukocyte-endothelial interactions have been characterized, functionally important endogenous inhibitors of leukocyte adhesion have not been identified. Here, we describe the endothelial-derived secreted molecule, developmental endothelial locus-1 (Del-1), as an anti-adhesive factor that interferes with the integrin LFA-1-dependent leukocyte-endothelial adhesion. Endothelial Del-1-deficiency increased LFA-1-dependent leukocyte adhesion in vitro and in vivo. Del-1-/-mice displayed significantly higher neutrophil accumulation in LPS-induced lung inflammation in vivo, which was reversed in Del-1/LFA-1-double deficient mice. Thus, Del-1 is an endogenous inhibitor of inflammatory cell recruitment and could provide a basis for targeting leukocyte-endothelial interactions in disease.Leukocyte extravasation is integral to the response to infection or injury and to inflammation and autoimmunity. Leukocyte recruitment comprises a well coordinated cascade of adhesive events including selectin-mediated rolling, firm adhesion of leukocytes to endothelial cells and & This manuscript has been accepted for publication in Science. This version has not undergone final editing. Please refer to the complete version of record at http://www.sciencemag.org/. The manuscript may not be reproduced or used in any manner that does not fall within the fair use provisions of the Copyright Act without the prior, written permission of AAAS. †To whom correspondence should be addressed chavakist@mail.nih.gov. * EYC and EC contributed equally # MAC and HL contributed equally NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript their subsequent transendothelial migration. The interaction between LFA-1 (αLβ2, CD11a/ CD18) and endothelial ICAM-1 is crucial during firm endothelial adhesion of leukocytes (1-5). Whereas numerous adhesion receptors promoting inflammatory cell recruitment have been identified, very little information exists about endogenous inhibitors of the leukocyte adhesion cascade (1-7). Developmental endothelial locus-1 (Del-1) is a glycoprotein that is secreted by endothelial cells and can associate with the endothelial cell surface and the extracellular matrix (8-10). Del-1 is regulated upon hypoxia or vascular injury and has been implicated in vascular remodelling during angiogenesis (10-12). Here, we sought to determine whether endothelial-derived Del-1 participates in leukocyte-endothelial interactions. RT-PCR analysis revealed Del-1 mRNA predominantly in the brain and lung, with no expression in liver, spleen, or whole blood (Fig. 1A and fig. S1A). Del-1 was expressed in WT but not in Del-1-/-murine lung endothelial cells (Fig. 1B, 9). Immunohistochemistry of lung tissues demonstrated the presence of Del-1 in vessels, as observed by co-staining with the endothelial marker PECAM-1 ( fig. S1B).To determine whether Del-1 participates in leukocyte recruitmen...

Inositol-requiring enzyme 1 (IRE1) is a proximal endoplasmic reticulum (ER) stress sensor and a central mediator of the unfolded protein response. In a human glioma model, inhibition of IRE1α correlated with down-regulation of prevalent proangiogenic factors such as VEGF-A, IL-1β, IL-6, and IL-8. Significant up-regulation of antiangiogenic gene transcripts was also apparent. These transcripts encode SPARC, decorin, thrombospondin-1, and other matrix proteins functionally linked to mesenchymal differentiation and glioma invasiveness. In vivo, using both the chick chorio-allantoic membrane assay and a mouse orthotopic brain model, we observed in tumors underexpressing IRE1: (i) reduction of angiogenesis and blood perfusion, (ii) a decreased growth rate, and (iii) extensive invasiveness and blood vessel cooption. This phenotypic change was consistently associated with increased overall survival in glioma-implanted recipient mice. Ectopic expression of IL-6 in IRE1-deficient tumors restored angiogenesis and neutralized vessel cooption but did not reverse the mesenchymal/infiltrative cell phenotype. The ischemiaresponsive IRE1 protein is thus identified as a key regulator of tumor neovascularization and invasiveness.tumor ischemia | unfolded protein response | mesenchymal drift

A hypoxic microenvironment induces resistance to alkylating agents by activating targets in the mammalian target of rapamycin (mTOR) pathway. The molecular mechanisms involved in this mTOR-mediated hypoxia-induced chemoresistance, however, are unclear. Here we identify the mTOR target N-myc downstream regulated gene 1 (NDRG1) as a key determinant of resistance toward alkylating chemotherapy, driven by hypoxia but also by therapeutic measures such as irradiation, corticosteroids, and chronic exposure to alkylating agents via distinct molecular routes involving hypoxia-inducible factor (HIF)-1alpha, p53, and the mTOR complex 2 (mTORC2)/serum glucocorticoid-induced protein kinase 1 (SGK1) pathway. Resistance toward alkylating chemotherapy but not radiotherapy was dependent on NDRG1 expression and activity. In posttreatment tumor tissue of patients with malignant gliomas, NDRG1 was induced and predictive of poor response to alkylating chemotherapy. On a molecular level, NDRG1 bound and stabilized methyltransferases, chiefly O 6 -methylguanine-DNA methyltransferase (MGMT), a key enzyme for resistance to alkylating agents in glioblastoma patients. In patients with glioblastoma, MGMT promoter methylation in tumor tissue was not more predictive for response to alkylating chemotherapy in patients who received concomitant corticosteroids. P rimary or acquired antitumor therapy resistance is one of the major obstacles in oncology. For glioma, to date, this is pivotal for the standard of care, radiotherapy, and temozolomide (TMZ) alkylating chemotherapy. The DNA repair protein O 6

Lumbar drainage of CSF led to a significant and clinically relevant reduction in ICP. The risk of cerebral herniation can be minimized by performing lumbar drainage only in cases with discernible basal cisterns.

In human inflammatory diseases, we identified endothelial angiopoietin-2 (Ang-2) expression to be strongly associated with inflammations mediated by myeloid cells but not lymphocytes. To identify the underlying mechanism, we made use of a transgenic mouse model with inducible endothelial cell-specific expression of Ang-2. In this model, in the absence of inflammatory stimuli, long-term expression of Ang-2 led to a time-dependent accumulation of myeloid cells in numerous organs, suggesting that Ang-2 is sufficient to recruit myeloid cells. In models of acute inflammation, such as delayed-type hypersensitivity and peritonitis, Ang-2 transgenic animals showed an increased responsiveness. Intravital fluorescence video microscopy revealed augmented cell adhesion as an underlying event. Consequently, we demonstrated that Ang-2 is able to induce strong monocyte adhesion under shear in vitro, which could be blocked by antibodies to ␤ 2 -integrin. Taken together, our results describe Ang-2 as a novel, endothelialderived regulator of myeloid cell infiltration that modulates ␤ 2 -integrinmediated adhesion in a paracrine manner. (Blood. 2011;118(18):5050-5059)

Background: The pathogenesis of moyamoya disease (MMD) is still unknown. The detection of inflammatory molecules such as cytokines, chemokines and growth factors in MMD patients' biological fluids supports the hypothesis that an abnormal angiogenesis is implicated in MMD pathogenesis. However, it is unclear whether these anomalies are the consequences of the disease or rather causal factors as well as these mechanisms remain insufficient to explain the pathophysiology of MMD. The presence of a family history in about 9-15% of Asian patients, the highly variable incidence rate between different ethnic and sex groups and the age of onset support the role of genetic factors in MMD pathogenesis. However, although some genetic loci have been associated with MMD, few of them have been replicated in independent series. Recently, RNF213 gene was shown to be strongly associated with MMD occurrence with a founder effect in East Asian patients. However, the mechanisms leading from RNF213 mutations to MMD clinical features are still unknown. Summary: The research on pathogenic mechanism of MMD is in its infancy. MMD is probably a complex and heterogeneous disorder, including different phenotypes and genotypes, in which more than a single factor is implicated. Key Message: Since the diagnosis of MMD is rapidly increasing worldwide, the development of more efficient stratifying risk systems, including both clinical but also biological drivers became imperative to improve our ability of predict prognosis and to develop mechanism-tailored interventions.

The AIRO(®) system is an easy-to-use and versatile iCT for navigated spinal instrumentation and provides high pedicle screw accuracy rates. Although the authors' experience suggests that the learning curve associated with AIRO(®)-based spinal navigation is steep, a systematic user-based approach to the technology is required.

Rationale:The extracellular matrix (ECM) is a major determinant of the structural integrity and functional properties of the myocardium in common pathological conditions, and changes in vasculature contribute to cardiac dysfunction. Collagen (Col) XV is preferentially expressed in the ECM of cardiac muscle and microvessels.Objective: We aimed to characterize the ECM, cardiovascular function and responses to elevated cardiovascular load in mice lacking Col XV (Col15a1 ؊/؊ ) to define its functional role in the vasculature and in age-and hypertension-associated myocardial remodeling. Methods and Results:Cardiac structure and vasculature were analyzed by light and electron microscopy.Cardiac function, intraarterial blood pressure, microhemodynamics, and gene expression profiles were studied using echocardiography, telemetry, intravital microscopy, and PCR, respectively. Experimental hypertension was induced with angiotensin II or with a nitric oxide synthesis inhibitor. Under basal conditions, lack of Col XV resulted in increased permeability and impaired microvascular hemodynamics, distinct early-onset and age-dependent defects in heart structure and function, a poorly organized fibrillar collagen matrix with marked interstitial deposition of nonfibrillar protein aggregates, increased tissue stiffness, and irregularly organized cardiomyocytes. In response to experimental hypertension, Col15a1 gene expression was increased in the left ventricle of wild-type mice, and mRNA expression of natriuretic peptides (ANP and BNP) and ECM modeling were abnormal in Col15a1 ؊/؊ mice. Key Words: cardiomyopathy Ⅲ collagen Ⅲ extracellular matrix Ⅲ hypertension Ⅲ microcirculation T he extracellular matrix (ECM) has an important role in cardiac remodeling, defined by the adaptive changes in left ventricular structure, geometry, and function that follow cardiovascular stress in hypertensive heart disease, cardiomyopathies, or myocardial infarction and also as a function of age. 1 Degradation of myocardial collagens results in decreased ventricular stiffness and dilatation, whereas an increase in the total interstitial collagen content and crosslinking results in a stiffer myocardium and ventricular diastolic dysfunction. 2 Cardiomyopathy may result from a variety of acquired or genetic factors. In the absence of coronary artery disease, a significant proportion of cardiomyopathies are attributable to a genetic cause, eg, hereditary forms are present in approximately 30% to 50% of patients experiencing dilative cardiomyopathy (DCM), and mutations in more than 30 genes have been linked to this disease. 3 Many defects in cytoskeletal and sarcomeric proteins involved in cardiomyocyte contraction and force production have been associated with familial DCM, but most of the genetic defects and pathophysiological mechanisms have still not been identified. 4 Recent studies using genetically modified mice suggest that altered cell-ECM interactions and cell-cell adhesion via the intercalated discs may be involved in DCM pathogenesis. [5][6]...