Cingulin Binds to the ZU5 Domain of Scaffolding Protein ZO-1 to Promote Its Extended Conformation, Stabilization, and Tight Junction Accumulation

Zonula occludens-1 (ZO-1), the major scaffolding protein of tight junctions (TJs), recruits the cytoskeleton-associated proteins cingulin (CGN) and paracingulin (CGNL1) to TJs by binding to their N-terminal ZO-1 interaction motif. The conformation of ZO-1 can be either folded or extended, depending on cytoskeletal tension and intramolecular and intermolecular interactions, and only ZO-1 in the extended conformation recruits the transcription factor DbpA to TJs. However, the sequences of ZO-1 that interact with CGN and CGNL1 and the role of TJ proteins in ZO-1 TJ assembly are not known. Here, we used glutathione-S-transferase pulldowns and immunofluorescence microscopy to show that CGN and CGNL1 bind to the C-terminal ZU5 domain of ZO-1 and that this domain is required for CGN and CGNL1 recruitment to TJs and to phase-separated ZO-1 condensates in cells. We show that KO of CGN, but not CGNL1, results in decreased accumulation of ZO-1 at TJs. Furthermore, ZO-1 lacking the ZU5 domain showed decreased accumulation at TJs, was detectable along lateral contacts, had a higher mobile fraction than full-length ZO-1 by fluorescence recovery after photobleaching analysis, and had a folded conformation, as determined by structured illumination microscopy of its N-terminal and C-terminal ends. The CGN-ZU5 interaction promotes the extended conformation of ZO-1, since binding of the CGN-ZO-1 interaction motif region to ZO-1 resulted in its interaction with DbpA in cells and in vitro. Together, these results show that binding of CGN to the ZU5 domain of ZO-1 promotes ZO-1 stabilization and accumulation at TJs by promoting its extended conformation

Infective endocarditis in patients after percutaneous pulmonary valve implantation with the stent-mounted bovine jugular vein valve : clinical experience and evaluation of the modified Duke criteria

Percutaneous pulmonary valve implantation (PPVI) has proven good hemodynamic results. As infective endocarditis (IE) remains a potential complication with limited available clinical data, we reviewed our patient records to improve future strategies of IE prevention, diagnosis and treatment. Medical records of all patients diagnosed with Melody® valve IE according to the modified Duke criteria were retrospectively analyzed in three Belgian tertiary centers. 23 IE episodes in 22 out of 240 patients were identified (incidence 2.4% / patient year) with a clear male predominance (86%). Median age at IE was 17.9 years (range 8.2-45.9 years) and median time from PPVI to IE was 2.4 years (range 0.7-8 years). Streptococcal species caused 10 infections (43%), followed by Staphylococcus aureus (n = 5, 22%). In 13/23 IE episodes a possible entry-point was identified (57%). IE was classified as definite in 15 (65%) and as possible in 8 (35%) cases due to limitations of imaging. Echocardiography visualized vegetations in only 10 patients. PET-CT showed positive FDG signals in 5/7 patients (71%) and intracardiac echocardiography a vegetation in 1/1 patient (100%). Eleven cases (48%) had a hemodynamically relevant pulmonary stenosis at IE presentation. Nine early and 6 late percutaneous or surgical re-interventions were performed. No IE related deaths occurred. IE after Melody® valve PPVI is associated with a relevant need of re-interventions. Communication to patients and physicians about risk factors is essential in prevention. The modified Duke criteria underperformed in diagnosing definite IE, but inclusion of new imaging modalities might improve diagnostic performance

Uniting to address paediatric heart disease in Africa: Advocacy from Rwanda

Paediatric heart disease causes death or disability in 15 million children around the world each year – a fi gure staggeringly disproportionate to available and relevant international funding and support. Although 80% of the burden of cardiovascular disorders fall in low- and middleincome countries, poor countries have a very limited capacity to build a system of care to address heart disease, including prevention, care, control and research. In this article, authors who work in or with Rwanda’s public sector aim to describe the current state of heart disease among children, what is currently being done to manage care and future directions for the national programme. As the world turns its attention to non-communicable diseases and seeks to ensure that they fi nd a prominent place in the post-2015 development agenda, it is essential to ensure that children are not left behind

Graafschade sinds mei 2018. Alle ballen op de grondroerder

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Structural Measurements and Adjustments for Growth

Quantitative assessment of the size of cardiovascular structures is a powerful tool that has become an essential aspect of the echocardiographic exam. Clinical use of these measurements requires an understanding of how they relate to normal values as well as their pathophysiologic and prognostic significance. Although adjustment for body size and cardiac output is universally important, it has its greatest impact in children because of the need for longitudinal assessment during somatic growth. There is a large literature devoted to cardiovascular allometry, which refers to the study or measurement of the size of the cardiovascular system in relation to the entire organism. This chapter reviews the theoretical and technical aspects of cardiovascular allometry and its importance to echocardiograph

Theoretical and empirical derivation of cardiovascular allometric relationships in children.

Basic fluid dynamic principles were used to derive a theoretical model of optimum cardiovascular allometry, the relationship between somatic and cardiovascular growth. The validity of the predicted models was then tested against the size of 22 cardiovascular structures measured echocardiographically in 496 normal children aged 1 day to 20 yr, including valves, pulmonary arteries, aorta and aortic branches, pulmonary veins, and left ventricular volume. Body surface area (BSA) was found to be a more important determinant of the size of each of the cardiovascular structures than age, height, or weight alone. The observed vascular and valvar dimensions were in agreement with values predicted from the theoretical models. Vascular and valve diameters related linearly to the square root of BSA, whereas valve and vascular areas related to BSA. The relationship between left ventricular volume and body size fit a complex model predicted by the nonlinear decrease of heart rate with growth. Overall, the relationship between cardiac output and body size is the fundamental driving factor in cardiovascular allometry

Influence of age and low afterload on the stress-velocity relation of the left ventricle.

The relation between systolic meridional wall stress (WS) and velocity of circumferential fiber shortening (VcFc) is widely accepted as a preload-independent index of contractility, with a linear relation in most subjects older than 2 y. However, this relation seems to become different in infants and after administration of inotropic agents. We decided to study the nature of the stress-velocity relation by a cross-sectional assessment of the influence of age, low afterload, and increased contractility. Study subjects were 30 healthy infants, 32 healthy older children, and 35 asymptomatic older children after completion of anthracycline chemotherapy. WS and VcFc at rest were studied in these infants and children. WS and VcFc were also studied after dobutamine infusion in both groups of older children. Linear regression analysis of the stress-velocity relation showed parallel slopes between the older children at rest and the post anthracycline children after dobutamine. The regression lines between the infants at rest and the healthy older children after dobutamine were also parallel, but with a different and steeper slope compared with the former groups. When comparing the stress-velocity relation of the overall population at rest with the overall population after dobutamine, the resulting regression lines are curvilinear and parallel, with a steeper slope at low afterload. The stress-velocity relation in infants and after dobutamine, resulting in low afterload is different compared with the stress- velocity relation in older children at rest and at higher afterload. Data of the overall population at rest and after dobutamine suggest a curvilinear relation