Healthcare professionals' perspectives on implementation of universal tumor DNA testing in ovarian cancer patients: multidisciplinary focus groups.

Universal tumor DNA testing in epithelial ovarian cancer patients can function not only as an efficient prescreen for hereditary cancer testing, but may also guide treatment choices. This innovation, introduced as Tumor-First workflow, offers great opportunities, but ensuring optimal multidisciplinary collaboration is a challenge. We investigated factors that were relevant and important for large-scale implementation. In three multidisciplinary online focus groups, healthcare professionals (gynecologic oncologists, pathologists, clinical geneticists, and clinical laboratory specialists) were interviewed on factors critical for the implementation of the Tumor-First workflow. Recordings were transcribed for analysis in Atlas.ti according to the framework of Flottorp that categorizes seven implementation domains. Healthcare professionals from all disciplines endorse implementation of the Tumor-First workflow, but more detailed standardization and advice regarding the logistics of the workflow were needed. Healthcare professionals explored ways to stay informed about the different phases of the workflow and the results. They emphasized the importance of including all epithelial ovarian cancer patients in the workflow and monitoring this inclusion. Overall, healthcare professionals would appreciate supporting material for the implementation of the Tumor-First workflow in the daily work routine. Focus group discussions have revealed factors for developing a tailored implementation strategy for the Tumor-First workflow in order to optimize care for epithelial ovarian cancer patients. Future innovations affecting multidisciplinary oncology teams including clinical geneticists can benefit from the lessons learned.

Vascular Hypothesis of Alzheimer Disease: Topical Review of Mouse Models.

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Reciprocal organ interactions during heart failure: a position paper from the ESC Working Group on Myocardial Function.

Heart failure-either with reduced or preserved ejection fraction (HFrEF/HFpEF)-is a clinical syndrome of multifactorial and gender-dependent aetiology, indicating the insufficiency of the heart to pump blood adequately to maintain blood flow to meet the body's needs. Typical symptoms commonly include shortness of breath, excessive fatigue with impaired exercise capacity, and peripheral oedema, thereby alluding to the fact that heart failure is a syndrome that affects multiple organ systems. Patients suffering from progressed heart failure have a very limited life expectancy, lower than that of numerous cancer types. In this position paper, we provide an overview regarding interactions between the heart and other organ systems, the clinical evidence, underlying mechanisms, potential available or yet-to-establish animal models to study such interactions and finally discuss potential new drug interventions to be developed in the future. Our working group suggests that more experimental research is required to understand the individual molecular mechanisms underlying heart failure and reinforces the urgency for tailored therapeutic interventions that target not only the heart but also other related affected organ systems to effectively treat heart failure as a clinical syndrome that affects and involves multiple organs.

Arterial Remodeling of the Intracranial Arteries in Patients With Hypertension and Controls: A Postmortem Study.

The intracranial arteries play a major role in cerebrovascular disease, but arterial remodeling due to hypertension has not been well described in humans. We aimed to quantify this remodeling for: the basilar artery, the vertebral, internal carotid, middle/anterior (inferior)/posterior cerebral, posterior communicating, and superior cerebellar arteries of the circle of Willis. Ex vivo circle of Willis specimens, selected from individuals with (n=24) and without (n=25) a history of hypertension, were imaged at 7T magnetic resonance imaging using a 3-dimensional gradient-echo sequence. Subsequently, histological analysis was performed. We validated the vessel wall thickness and area measurements from magnetic resonance imaging against histology. Next, we investigated potential differences in vessel wall thickness and area between both groups using both techniques. Finally, using histological analysis, we investigated potential differences in arterial wall stiffness and atherosclerotic plaque severity and load. All analyses were unadjusted. Magnetic resonance imaging and histology showed comparable vessel wall thickness (mean difference: 0.04 mm (limits of agreement:-0.12 to 0.19 mm) and area (0.43 mm2 [-0.97 to 1.8 mm2]) measurements. We observed no statistically significant differences in vessel wall thickness and area between both groups using either technique. Histological analysis showed early and advanced atherosclerotic plaques in almost all arteries for both groups. The arterial wall stiffness was significantly higher for the internal carotid artery in the hypertensive group. Concluding, we did not observe vessel wall thickening in the circle of Willis arteries in individuals with a history of hypertension using either technique. Using histological analysis, we observed a difference in vessel wall composition for the internal carotid artery.

Profiling the unique protective properties of intracranial arterial endothelial cells.

Cardiovascular disorders, like atherosclerosis and hypertension, are increasingly known to be associated with vascular cognitive impairment (VCI). In particular, intracranial atherosclerosis is one of the main causes of VCI, although plaque development occurs later in time and is structurally different compared to atherosclerosis in extracranial arteries. Recent data suggest that endothelial cells (ECs) that line the intracranial arteries may exert anti-atherosclerotic effects due to yet unidentified pathways. To gain insights into underlying mechanisms, we isolated post-mortem endothelial cells from both the intracranial basilar artery (BA) and the extracranial common carotid artery (CCA) from the same individual (total of 15 individuals) with laser capture microdissection. RNA sequencing revealed a distinct molecular signature of the two endothelial cell populations of which the most prominent ones were validated by means of qPCR. Our data reveal for the first time that intracranial artery ECs exert an immune quiescent phenotype. Secondly, genes known to be involved in the response of ECs to damage (inflammation, differentiation, adhesion, proliferation, permeability and oxidative stress) are differentially expressed in intracranial ECs compared to extracranial ECs. Finally, Desmoplakin (DSP) and Hop Homeobox (HOPX), two genes expressed at a higher level in intracranial ECs, and Sodium Voltage-Gated Channel Beta Subunit 3 (SCN3B), a gene expressed at a lower level in intracranial ECs compared to extracranial ECs, were shown to be responsive to shear stress and/or hypoxia. With our data we present a set of intracranial-specific endothelial genes that may contribute to its protective phenotype, thereby supporting proper perfusion and consequently may preserve cognitive function. Deciphering the molecular regulation of the vascular bed in the brain may lead to the identification of novel potential intervention strategies to halt vascular associated disorders, such as atherosclerosis and vascular cognitive dysfunction.

Cgnl1, an endothelial junction complex protein, regulates GTPase mediated angiogenesis.

AIMS: The formation of cell-cell and cell-extra cellular matrix (ECM) contacts by endothelial cells (ECs) is crucial for the stability and integrity of a vascular network. We previously identified cingulin-like 1 (Cgnl1) in a transcriptomic screen for new angiogenic modulators. Here we aim to study the function of the cell-cell junction associated protein Cgnl1 during vessel formation. METHODS AND RESULTS: Unlike family member cingulin, Cgnl1 expression is enriched in ECs during vascular growth. Cgnl1 is important for the formation of multicellular tubule structures, as shown in vitro using loss-of function assays in a 3D matrix co-culture system that uses primary human ECs and supporting mural cells. Further studies revealed that Cgnl1 regulates vascular growth by promoting Ve-cadherin association with the actin cytoskeleton, thereby stabilizing adherens junctions. Cgnl1 also regulates focal adhesion assembly in response to ECM contact, promoting vinculin and paxillin recruitment and focal adhesion kinase signalling. In vivo, we demonstrate in a postnatal retinal vascular development model in mice that Cgnl1 function is crucial for sustaining neovascular growth and stability. CONCLUSIONS: Our data demonstrate a functional relevance for Cgnl1 as a defining factor in new vessel formation both in vitro and in vivo.

SoxF factors induce Notch1 expression via direct transcriptional regulation during early arterial development.

Arterial specification and differentiation are influenced by a number of regulatory pathways. While it is known that the Vegfa-Notch cascade plays a central role, the transcriptional hierarchy controlling arterial specification has not been fully delineated. To elucidate the direct transcriptional regulators of Notch receptor expression in arterial endothelial cells, we used histone signatures, DNaseI hypersensitivity and ChIP-seq data to identify enhancers for the human NOTCH1 and zebrafish notch1b genes. These enhancers were able to direct arterial endothelial cell-restricted expression in transgenic models. Genetic disruption of SoxF binding sites established a clear requirement for members of this group of transcription factors (SOX7, SOX17 and SOX18) to drive the activity of these enhancers in vivo Endogenous deletion of the notch1b enhancer led to a significant loss of arterial connections to the dorsal aorta in Notch pathway-deficient zebrafish. Loss of SoxF function revealed that these factors are necessary for NOTCH1 and notch1b enhancer activity and for correct endogenous transcription of these genes. These findings position SoxF transcription factors directly upstream of Notch receptor expression during the acquisition of arterial identity in vertebrates.

THSD1 preserves vascular integrity and protects against intraplaque haemorrhaging in ApoE-/- mice.

AIMS: Impairment of the endothelial barrier leads to microvascular breakdown in cardiovascular disease and is involved in intraplaque haemorrhaging and the progression of advanced atherosclerotic lesions that are vulnerable to rupture. The exact mechanism that regulates vascular integrity requires further definition. Using a microarray screen for angiogenesis-associated genes during murine embryogenesis, we identified thrombospondin type I domain 1 (THSD1) as a new putative angiopotent factor with unknown biological function. We sought to characterize the role of THSD1 in endothelial cells during vascular development and cardiovascular disease. METHODS AND RESULTS: Functional knockdown of Thsd1 in zebrafish embryos and in a murine retina vascularization model induced severe haemorrhaging without affecting neovascular growth. In human carotid endarterectomy specimens, THSD1 expression by endothelial cells was detected in advanced atherosclerotic lesions with intraplaque haemorrhaging, but was absent in stable lesions, implying involvement of THSD1 in neovascular bleeding. In vitro, stimulation with pro-atherogenic factors (3% O2 and TNFα) decreased THSD1 expression in human endothelial cells, whereas stimulation with an anti-atherogenic factor (IL10) showed opposite effect. Therapeutic evaluation in a murine advanced atherosclerosis model showed that Thsd1 overexpression decreased plaque vulnerability by attenuating intraplaque vascular leakage, subsequently reducing macrophage accumulation and necrotic core size. Mechanistic studies in human endothelial cells demonstrated that THSD1 activates FAK-PI3K, leading to Rac1-mediated actin cytoskeleton regulation of adherens junctions and focal adhesion assembly. CONCLUSION: THSD1 is a new regulator of endothelial barrier function during vascular development and protects intraplaque microvessels against haemorrhaging in advanced atherosclerotic lesions.

Ribosomal Protein Mutations Result in Constitutive p53 Protein Degradation through Impairment of the AKT Pathway.

Mutations in ribosomal protein (RP) genes can result in the loss of erythrocyte progenitor cells and cause severe anemia. This is seen in patients with Diamond-Blackfan anemia (DBA), a pure red cell aplasia and bone marrow failure syndrome that is almost exclusively linked to RP gene haploinsufficiency. While the mechanisms underlying the cytopenia phenotype of patients with these mutations are not completely understood, it is believed that stabilization of the p53 tumor suppressor protein may induce apoptosis in the progenitor cells. In stark contrast, tumor cells from zebrafish with RP gene haploinsufficiency are unable to stabilize p53 even when exposed to acute DNA damage despite transcribing wild type p53 normally. In this work we demonstrate that p53 has a limited role in eliciting the anemia phenotype of zebrafish models of DBA. In fact, we find that RP-deficient embryos exhibit the same normal p53 transcription, absence of p53 protein, and impaired p53 response to DNA damage as RP haploinsufficient tumor cells. Recently we reported that RP mutations suppress activity of the AKT pathway, and we show here that this suppression results in proteasomal degradation of p53. By re-activating the AKT pathway or by inhibiting GSK-3, a downstream modifier that normally represses AKT signaling, we are able to restore the stabilization of p53. Our work indicates that the anemia phenotype of zebrafish models of DBA is dependent on factors other than p53, and may hold clinical significance for both DBA and the increasing number of cancers revealing spontaneous mutations in RP genes.

Sox7 controls arterial specification in conjunction with hey2 and efnb2 function.

SoxF family members have been linked to arterio-venous specification events and human pathological conditions, but in contrast to Sox17 and Sox18, a detailed in vivo analysis of a Sox7 mutant model is still lacking. In this study we generated zebrafish sox7 mutants to understand the role of Sox7 during vascular development. By in vivo imaging of transgenic zebrafish lines we show that sox7 mutants display a short circulatory loop around the heart as a result of aberrant connections between the lateral dorsal aorta (LDA) and either the venous primary head sinus (PHS) or the common cardinal vein (CCV). In situ hybridization and live observations in flt4:mCitrine transgenic embryos revealed increased expression levels of flt4 in arterial endothelial cells at the exact location of the aberrant vascular connections in sox7 mutants. An identical circulatory short loop could also be observed in newly generated mutants for hey2 and efnb2. By genetically modulating levels of sox7, hey2 and efnb2 we demonstrate a genetic interaction of sox7 with hey2 and efnb2. The specific spatially confined effect of loss of Sox7 function can be rescued by overexpressing the Notch intracellular domain (NICD) in arterial cells of sox7 mutants, placing Sox7 upstream of Notch in this aspect of arterial development. Hence, sox7 levels are crucial in arterial specification in conjunction with hey2 and efnb2 function, with mutants in all three genes displaying shunt formation and an arterial block.

Divergence of zebrafish and mouse lymphatic cell fate specification pathways.

In mammals, the homeodomain transcription factor Prox1 acts as the central regulator of lymphatic cell fate. Its restricted expression in a subset of cardinal vein cells leads to a switch towards lymphatic specification and hence represents a prerequisite for the initiation of lymphangiogenesis. Murine Prox1-null embryos lack lymphatic structures, and sustained expression of Prox1 is indispensable for the maintenance of lymphatic cell fate even at adult stages, highlighting the unique importance of this gene for the lymphatic lineage. Whether this pre-eminent role of Prox1 within the lymphatic vasculature is conserved in other vertebrate classes has remained unresolved, mainly owing to the lack of availability of loss-of-function mutants. Here, we re-examine the role of Prox1a in zebrafish lymphangiogenesis. First, using a transgenic reporter line, we show that prox1a is initially expressed in different endothelial compartments, becoming restricted to lymphatic endothelial cells only at later stages. Second, using targeted mutagenesis, we show that Prox1a is dispensable for lymphatic specification and subsequent lymphangiogenesis in zebrafish. In line with this result, we found that the functionally related transcription factors Coup-TFII and Sox18 are also dispensable for lymphangiogenesis. Together, these findings suggest that lymphatic commitment in zebrafish and mice is controlled in fundamentally different ways.