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1.
Trends Mol Med ; 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38658206

ABSTRACT

Traditionally, anticancer therapies focus on restraining uncontrolled proliferation. However, these cytotoxic therapies expose cancer cells to direct killing, instigating the process of natural selection favoring survival of resistant cells that become the foundation for tumor progression and therapy failure. Recognizing this phenomenon has prompted the development of alternative therapeutic strategies. Here we propose strategies targeting cancer hallmarks beyond proliferation, aiming at re-educating cancer cells towards a less malignant phenotype. These strategies include controlling cell dormancy, transdifferentiation therapy, normalizing the cancer microenvironment, and using migrastatic therapy. Adaptive resistance to these educative strategies does not confer a direct proliferative advantage to resistant cells, as non-resistant cells are not subject to eradication, thereby delaying or preventing the development of therapy-resistant tumors.

2.
Curr Opin Cell Biol ; 86: 102302, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38194749

ABSTRACT

Notch signaling controls multiple aspects of embryonic development and adult homeostasis. Alagille syndrome is usually caused by a single mutation in the jagged canonical Notch ligand 1 (JAG1), and manifests with liver disease and cardiovascular symptoms that are a direct consequence of JAG1 haploinsufficiency. Recent insights into Jag1/Notch-controlled developmental and homeostatic processes explain how pathology develops in the hepatic and cardiovascular systems and, together with recent elucidation of mechanisms modulating liver regeneration, provide a basis for therapeutic efforts. Importantly, disease presentation can be regulated by genetic modifiers, that may also be therapeutically leverageable. Here, we summarize recent insights into how Jag1 controls processes of relevance to Alagille syndrome, focused on Jag1/Notch functions in hepatic and cardiovascular development and homeostasis.


Subject(s)
Alagille Syndrome , Humans , Alagille Syndrome/diagnosis , Alagille Syndrome/genetics , Alagille Syndrome/therapy , Serrate-Jagged Proteins , Membrane Proteins/genetics , Membrane Proteins/metabolism , Calcium-Binding Proteins/genetics , Intercellular Signaling Peptides and Proteins/genetics , Jagged-1 Protein/genetics
3.
Sensors (Basel) ; 23(21)2023 Oct 30.
Article in English | MEDLINE | ID: mdl-37960520

ABSTRACT

This article represents the first paper in a two-part series dealing with safety during tram-pedestrian collisions. This research is dedicated to the safety of trams for pedestrians during collisions and is motivated by the increased number of lethal cases. The first part of this paper includes an overview of tram face development from the earliest designs to the current ones in use and, at the same time, provides a synopsis and explanation of the technical context, including a link to current and forthcoming legislation. The historical design development can be characterised by three steps, from an almost vertical front face, to leaned and pointed shapes, to the current inclined low-edged windshield without a protruding coupler. However, since most major manufacturers now export their products worldwide and customisation is only of a technically insignificant nature, our conclusions are generalisable (supported by the example of Berlin). The most advantageous shape of the tram's front, minimising the effects on pedestrians in all collision phases, has evolved rather spontaneously and was unprompted, and it is now being built into the European Commission regulations. The goal of the second part of this paper is to conduct a series of tram-pedestrian collisions with a focus on the frontal and side impacts using a crash test dummy (anthropomorphic test device-ATD). Four tram types approaching the collision at four different impact speeds (5 km/h, 10 km/h, 15 km/h, and 20 km/h) were used. The primary outcome variable was the resultant head acceleration. The risk and severity of possible head injuries were assessed using the head injury criterion (HIC15) and its linkage to the injury level on the Abbreviated Injury Scale (AIS). The results showed increasing head impacts with an increasing speed for all tram types and collision scenarios. Higher values of head acceleration were reached during the frontal impact (17-124 g) compared to the side one (2-84 g). The HIC15 values did not exceed the value of 300 for any experimental setting, and the probability of AIS4+ injuries did not exceed 10%. The outcomes of tram-pedestrian collisions can be influenced by the ATD's position and orientation, the impact speed and front-end design of trams, and the site of initial contact.


Subject(s)
Craniocerebral Trauma , Pedestrians , Wounds and Injuries , Humans , Accidents, Traffic , Motor Vehicles , Walking
4.
CVIR Endovasc ; 6(1): 35, 2023 Jul 05.
Article in English | MEDLINE | ID: mdl-37405522

ABSTRACT

BACKGROUND: Endovascular aneurysm repair (EVAR) has created new possibilities for patients with abdominal aortic aneurysms (AAAs), and in recent years it has become tremendously popular. Use of EVAR in selected groups of patients allows mortality and morbidity to be reduced in comparison to open repair. However, complications such as endoleaks (ELs) can be of great concern and warrant urgent therapy to prevent sac rupture. CASE PRESENTATION: The case report presents urgent endovascular treatment of a high-risk type IA EL in a polymorbid 68-year-old patient 7 years after primary EVAR. The principle of treatment was parallel implantation of the proximal SG extension with the renal SG into the right renal artery (chimney technique). The subsequent type II collateral EL was treated by direct transabdominal AAA sac puncture and thrombin embolization. CONCLUSION: EL can be a cause for urgent intervention, but specific anatomic features often require specialized SG types which are not readily available. The chimney technique allows the use of immediately available stent grafts to address endoleak in the setting of impending abdominal aneurysm rupture.

5.
Microbiol Spectr ; 11(3): e0002823, 2023 06 15.
Article in English | MEDLINE | ID: mdl-37078868

ABSTRACT

The search for the "Holy Grail" in clinical diagnostic microbiology-a reliable, accurate, low-cost, real-time, easy-to-use method-has brought up several methods with the potential to meet these criteria. One is Raman spectroscopy, an optical, nondestructive method based on the inelastic scattering of monochromatic light. The current study focuses on the possible use of Raman spectroscopy for identifying microbes causing severe, often life-threatening bloodstream infections. We included 305 microbial strains of 28 species acting as causative agents of bloodstream infections. Raman spectroscopy identified the strains from grown colonies, with 2.8% and 7% incorrectly identified strains using the support vector machine algorithm based on centered and uncentred principal-component analyses, respectively. We combined Raman spectroscopy with optical tweezers to speed up the process and captured and analyzed microbes directly from spiked human serum. The pilot study suggests that it is possible to capture individual microbial cells from human serum and characterize them by Raman spectroscopy with notable differences among different species. IMPORTANCE Bloodstream infections are among the most common causes of hospitalizations and are often life-threatening. To establish an effective therapy for a patient, the timely identification of the causative agent and characterization of its antimicrobial susceptibility and resistance profiles are essential. Therefore, our multidisciplinary team of microbiologists and physicists presents a method that reliably, rapidly, and inexpensively identifies pathogens causing bloodstream infections-Raman spectroscopy. We believe that it might become a valuable diagnostic tool in the future. Combined with optical trapping, it offers a new approach where the microorganisms are individually trapped in a noncontact way by optical tweezers and investigated by Raman spectroscopy directly in a liquid sample. Together with the automatic processing of measured Raman spectra and comparison with a database of microorganisms, it makes the whole identification process almost real time.


Subject(s)
Sepsis , Spectrum Analysis, Raman , Humans , Spectrum Analysis, Raman/methods , Pilot Projects , Optical Tweezers , Algorithms
6.
Vasc Endovascular Surg ; 57(4): 373-378, 2023 May.
Article in English | MEDLINE | ID: mdl-36593684

ABSTRACT

OBJECTIVES: Transjugular intrahepatic portosystemic shunt (TIPS) is regularly used in treatment of clinically significant portal hypertension. Liver transplant recipients are, however, rarely indicated for the procedure. The study retrospectively examines the results of TIPS placement in 6 patients after OLT. METHODS: 4 males and 2 females (aged 36 to 62 years), treated with TIPS between 2007 a 2018, were included in the study. 5 patients had previously undergone liver transplantation for liver graft cirrhosis, 1 patient for Budd-Chiari syndrome. The piggyback caval reconstruction technique was selected in 4/6 cases. PH developed after OLT due to the recurrence of underlying liver condition and sinusoidal obstruction syndrome in half of the cases, respectively. Indications for TIPS were refractory ascites in 4 cases and variceal bleeding in 2 cases. RESULTS: Standard TIPS technique was used and technical success was achieved in all cases with a procedure-related complication in 1 patient. One patient died shortly after TIPS placement. The remaining patients all reported regression of clinically significant PH. Late complications appeared in 2 patients. Liver retransplantation after TIPS creation was performed in 1 case. Median TIPS patency was 55 months. 2/6 patient continue to thrive with a patent shunt. CONCLUSIONS: Transjugular intrahepatic portosystemic shunt in OLT recipients is technically feasible. Favorable clinical outcomes were reported particularly in patients treated for sinusoidal obstruction syndrome who were indicated to TIPS for refractory ascites.


Subject(s)
Esophageal and Gastric Varices , Hepatic Veno-Occlusive Disease , Liver Transplantation , Portasystemic Shunt, Transjugular Intrahepatic , Male , Female , Humans , Adult , Esophageal and Gastric Varices/etiology , Liver Transplantation/adverse effects , Portasystemic Shunt, Transjugular Intrahepatic/adverse effects , Portasystemic Shunt, Transjugular Intrahepatic/methods , Ascites/etiology , Ascites/surgery , Retrospective Studies , Hepatic Veno-Occlusive Disease/etiology , Treatment Outcome , Gastrointestinal Hemorrhage/etiology
7.
Vnitr Lek ; 68(8): 508-512, 2022.
Article in English | MEDLINE | ID: mdl-36575068

ABSTRACT

Deep vein thrombosis (DVT) is one of the most common diseases in developed countries with significant socioeconomic consequences. The severity of DVT lies in the potential for life-threatening pulmonary embolism and the development of chronic venous insufficiency, referred to as post-thrombotic syndrome. Virchow contributed to the understanding of the pathophysiological events that lead to thrombosis by describing three basic risk mechanisms. The first therapeutic attempts in the 17th century included venepuncture and the application of leeches. The first anticoagulant drug was heparin, which entered clinical practice after 1935. Subsequent commercialization of oral vitamin K antagonists (warfarin) and the advent of low molecular weight heparin along with compression therapy allowed the expansion of outpatient treatment of DVT. Recently, new oral anticoagulants have been introduced, leading to improved safety due to lower risk of bleeding complications and simplification of the treatment process. The next step in the development of therapeutic options are invasive methods of early thrombus removal, which significantly shorten the process and aim to reduce the occurrence of late complications. These methods include local catheter-directed thrombolysis using tissue plasminogen activator, mechanical thrombectomy and their combination called pharmaco-mechanical thrombectomy. The latter is currently used in patients with acute ilio-femoral DVT.


Subject(s)
Leeches , Venous Thrombosis , Humans , Animals , Tissue Plasminogen Activator/therapeutic use , Thrombolytic Therapy/methods , Femoral Vein , Anticoagulants/therapeutic use , Venous Thrombosis/drug therapy , Thrombectomy/methods , Treatment Outcome
8.
Nat Commun ; 12(1): 7046, 2021 12 02.
Article in English | MEDLINE | ID: mdl-34857782

ABSTRACT

Reconstruction of heterogeneity through single cell transcriptional profiling has greatly advanced our understanding of the spatial liver transcriptome in recent years. However, global transcriptional differences across lobular units remain elusive in physical space. Here, we apply Spatial Transcriptomics to perform transcriptomic analysis across sectioned liver tissue. We confirm that the heterogeneity in this complex tissue is predominantly determined by lobular zonation. By introducing novel computational approaches, we enable transcriptional gradient measurements between tissue structures, including several lobules in a variety of orientations. Further, our data suggests the presence of previously transcriptionally uncharacterized structures within liver tissue, contributing to the overall spatial heterogeneity of the organ. This study demonstrates how comprehensive spatial transcriptomic technologies can be used to delineate extensive spatial gene expression patterns in the liver, indicating its future impact for studies of liver function, development and regeneration as well as its potential in pre-clinical and clinical pathology.


Subject(s)
Genetic Heterogeneity , Liver/metabolism , Transcriptome , Animals , B-Lymphocytes/cytology , B-Lymphocytes/metabolism , Dendritic Cells/cytology , Dendritic Cells/metabolism , Endothelial Cells/cytology , Endothelial Cells/metabolism , Erythroblasts/cytology , Erythroblasts/metabolism , Female , Gene Expression Profiling , Gene Ontology , Hepatocytes/cytology , Hepatocytes/metabolism , Kupffer Cells/cytology , Kupffer Cells/metabolism , Liver/cytology , Macrophages/cytology , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Molecular Sequence Annotation , Neutrophils/cytology , Neutrophils/metabolism
9.
Cell Rep Methods ; 1(4)2021 08 23.
Article in English | MEDLINE | ID: mdl-34557863

ABSTRACT

Genetic loss and gain of function in mice have typically been studied by using knockout or knockin mice that take months to years to generate. To address this problem for the nervous system, we developed NEPTUNE (NEural Plate Targeting by in Utero NanoinjEction) to rapidly and flexibly transduce the neural plate with virus prior to neurulation, and thus manipulate the future nervous system. Stable integration in >95% of cells in the brain enabled long-term overexpression, and conditional expression was achieved by using cell-type-specific MiniPromoters. Knockdown of Olig2 by using NEPTUNE recapitulated the phenotype of Olig2 -/- embryos. We used NEPTUNE to investigate Sptbn2, mutations in which cause spinocerebellar ataxia type 5. Sptbn2 knockdown induced dose-dependent defects in the neural tube, embryonic turning, and abdominal wall closure, previously unreported functions for Sptbn2. NEPTUNE thus offers a rapid and cost-effective technique to test gene function in the nervous system and can reveal phenotypes incompatible with life.


Subject(s)
Neptune , Neural Tube Defects , Mice , Animals , Neural Tube/physiology , Brain , Gene Expression
10.
Stem Cell Res ; 45: 101770, 2020 05.
Article in English | MEDLINE | ID: mdl-32276221

ABSTRACT

Embryonic neural stem cells (NSCs), comprising neuroepithelial and radial glial cells, are indispensable precursors of neurons and glia in the mammalian developing brain. Since the process of neurogenesis occurs in a hypoxic environment, the question arises of how NSCs deal with low oxygen tension and whether it affects their stemness. Genes from the hypoxia-inducible factors (HIF) family are well known factors governing cellular response to hypoxic conditions. In this study, we have discovered that the endogenous stabilization of hypoxia-inducible factor 1α (Hif1α) during neural induction is critical for the normal development of the NSCs pool by preventing its premature depletion and differentiation. The knock-out of the Hif1α gene in mESC-derived neurospheres led to a decrease in self-renewal of NSCs, paralleled by an increase in neuronal differentiation. Similarly, neuroepithelial cells differentiated in hypoxia exhibited accelerated neurogenesis soon after Hif1α knock-down. In both models, the loss of Hif1α was accompanied by an immediate drop in neural repressor Hes1 levels while changes in Notch signaling were not observed. We found that active Hif1α/Arnt1 transcription complex bound to the evolutionarily conserved site in Hes1 gene promoter in both neuroepithelial cells and neural tissue of E8.5 - 9.5 embryos. Taken together, these results emphasize the novel role of Hif1α in the regulation of early NSCs population through the activation of neural repressor Hes1, independently of Notch signaling.


Subject(s)
Neural Stem Cells , Animals , Cell Differentiation , Cell Line , Hypoxia , Neurogenesis
11.
Neural Dev ; 13(1): 8, 2018 05 11.
Article in English | MEDLINE | ID: mdl-29751817

ABSTRACT

Generation of neurons in the embryonic neocortex is a balanced process of proliferation and differentiation of neuronal progenitor cells. Canonical Wnt signalling is crucial for expansion of radial glial cells in the ventricular zone and for differentiation of intermediate progenitors in the subventricular zone. We detected abundant expression of two transcrtiption factors mediating canonical Wnt signalling, Tcf7L1 and Tcf7L2, in the ventricular zone of the embryonic neocortex. Conditional knock-out analysis showed that Tcf7L2, but not Tcf7L1, is the principal Wnt mediator important for maintenance of progenitor cell identity in the ventricular zone. In the absence of Tcf7L2, the Wnt activity is reduced, ventricular zone markers Pax6 and Sox2 are downregulated and the neuroepithelial structure is severed due to the loss of apical adherens junctions. This results in decreased proliferation of radial glial cells, the reduced number of intermediate progenitors in the subventricular zone and hypoplastic forebrain. Our data show that canonical Wnt signalling, which is essential for determining the neuroepithelial character of the neocortical ventricular zone, is mediated by Tcf7L2.


Subject(s)
Neocortex/cytology , Neocortex/embryology , Neurogenesis/physiology , Neurons/physiology , Transcription Factor 7-Like 2 Protein/metabolism , Animals , Cell Count , Cell Differentiation/genetics , Cell Proliferation/genetics , Chloride-Bicarbonate Antiporters , Down-Regulation/genetics , Embryo, Mammalian , Hippocampus/cytology , Hippocampus/embryology , Mice , Mice, Transgenic , Mutation/genetics , Neural Stem Cells/physiology , Neuroglia , Retinal Ganglion Cells/physiology , SOXB1 Transcription Factors/metabolism , Signal Transduction/genetics , T-Box Domain Proteins/metabolism , Transcription Factor 7-Like 2 Protein/genetics , Wnt Proteins/metabolism
12.
Gastroenterology ; 154(4): 1080-1095, 2018 03.
Article in English | MEDLINE | ID: mdl-29162437

ABSTRACT

BACKGROUND & AIMS: Alagille syndrome is a genetic disorder characterized by cholestasis, ocular abnormalities, characteristic facial features, heart defects, and vertebral malformations. Most cases are associated with mutations in JAGGED1 (JAG1), which encodes a Notch ligand, although it is not clear how these contribute to disease development. We aimed to develop a mouse model of Alagille syndrome to elucidate these mechanisms. METHODS: Mice with a missense mutation (H268Q) in Jag1 (Jag1+/Ndr mice) were outbred to a C3H/C57bl6 background to generate a mouse model for Alagille syndrome (Jag1Ndr/Ndr mice). Liver tissues were collected at different timepoints during development, analyzed by histology, and liver organoids were cultured and analyzed. We performed transcriptome analysis of Jag1Ndr/Ndr livers and livers from patients with Alagille syndrome, cross-referenced to the Human Protein Atlas, to identify commonly dysregulated pathways and biliary markers. We used species-specific transcriptome separation and ligand-receptor interaction assays to measure Notch signaling and the ability of JAG1Ndr to bind or activate Notch receptors. We studied signaling of JAG1 and JAG1Ndr via NOTCH 1, NOTCH2, and NOTCH3 and resulting gene expression patterns in parental and NOTCH1-expressing C2C12 cell lines. RESULTS: Jag1Ndr/Ndr mice had many features of Alagille syndrome, including eye, heart, and liver defects. Bile duct differentiation, morphogenesis, and function were dysregulated in newborn Jag1Ndr/Ndr mice, with aberrations in cholangiocyte polarity, but these defects improved in adult mice. Jag1Ndr/Ndr liver organoids collapsed in culture, indicating structural instability. Whole-transcriptome sequence analyses of liver tissues from mice and patients with Alagille syndrome identified dysregulated genes encoding proteins enriched at the apical side of cholangiocytes, including CFTR and SLC5A1, as well as reduced expression of IGF1. Exposure of Notch-expressing cells to JAG1Ndr, compared with JAG1, led to hypomorphic Notch signaling, based on transcriptome analysis. JAG1-expressing cells, but not JAG1Ndr-expressing cells, bound soluble Notch1 extracellular domain, quantified by flow cytometry. However, JAG1 and JAG1Ndr cells each bound NOTCH2, and signaling from NOTCH2 signaling was reduced but not completely inhibited, in response to JAG1Ndr compared with JAG1. CONCLUSIONS: In mice, expression of a missense mutant of Jag1 (Jag1Ndr) disrupts bile duct development and recapitulates Alagille syndrome phenotypes in heart, eye, and craniofacial dysmorphology. JAG1Ndr does not bind NOTCH1, but binds NOTCH2, and elicits hypomorphic signaling. This mouse model can be used to study other features of Alagille syndrome and organ development.


Subject(s)
Alagille Syndrome/genetics , Jagged-1 Protein/genetics , Mutation, Missense , Alagille Syndrome/metabolism , Alagille Syndrome/pathology , Animals , Bile Ducts, Intrahepatic/metabolism , Bile Ducts, Intrahepatic/pathology , Cell Differentiation , Coculture Techniques , Disease Models, Animal , Female , Gene Expression Profiling/methods , Gene Expression Regulation, Developmental , Genetic Predisposition to Disease , HEK293 Cells , Humans , Jagged-1 Protein/metabolism , Male , Mice, Inbred C3H , Mice, Inbred C57BL , Mice, Transgenic , Morphogenesis , Organoids , Phenotype , Receptor, Notch2/genetics , Receptor, Notch2/metabolism , Signal Transduction , Transfection
13.
Sci Rep ; 7(1): 3160, 2017 06 09.
Article in English | MEDLINE | ID: mdl-28600563

ABSTRACT

In this work, we proposed a new data acquisition approach that significantly improves the repetition rates of Laser-Induced Breakdown Spectroscopy (LIBS) experiments, where high-end echelle spectrometers and intensified detectors are commonly used. The moderate repetition rates of recent LIBS systems are caused by the utilization of intensified detectors and their slow full frame (i.e. echellogram) readout speeds with consequent necessity for echellogram-to-1D spectrum conversion (intensity vs. wavelength). Therefore, we investigated a new methodology where only the most effective pixels of the echellogram were selected and directly used in the LIBS experiments. Such data processing resulted in significant variable down-selection (more than four orders of magnitude). Samples of 50 sedimentary ores samples (distributed in 13 ore types) were analyzed by LIBS system and then classified by linear and non-linear Multivariate Data Analysis algorithms. The utilization of selected pixels from an echellogram yielded increased classification accuracy compared to the utilization of common 1D spectra.

14.
Development ; 144(10): 1743-1763, 2017 05 15.
Article in English | MEDLINE | ID: mdl-28512196

ABSTRACT

Notch signaling regulates a vast array of crucial developmental processes. It is therefore not surprising that mutations in genes encoding Notch receptors or ligands lead to a variety of congenital disorders in humans. For example, loss of function of Notch results in Adams-Oliver syndrome, Alagille syndrome, spondylocostal dysostosis and congenital heart disorders, while Notch gain of function results in Hajdu-Cheney syndrome, serpentine fibula polycystic kidney syndrome, infantile myofibromatosis and lateral meningocele syndrome. Furthermore, structure-abrogating mutations in NOTCH3 result in CADASIL. Here, we discuss these human congenital disorders in the context of known roles for Notch signaling during development. Drawing on recent analyses by the exome aggregation consortium (EXAC) and on recent studies of Notch signaling in model organisms, we further highlight additional Notch receptors or ligands that are likely to be involved in human genetic diseases.


Subject(s)
Genetic Diseases, Inborn/embryology , Genetic Diseases, Inborn/genetics , Receptors, Notch/genetics , Abnormalities, Multiple/embryology , Abnormalities, Multiple/genetics , Alagille Syndrome/embryology , Alagille Syndrome/genetics , Animals , Developmental Biology , Ectodermal Dysplasia/embryology , Ectodermal Dysplasia/genetics , Hajdu-Cheney Syndrome/embryology , Hajdu-Cheney Syndrome/genetics , Hernia, Diaphragmatic/embryology , Hernia, Diaphragmatic/genetics , Humans , Limb Deformities, Congenital/embryology , Limb Deformities, Congenital/genetics , Meningocele/embryology , Meningocele/genetics , Scalp Dermatoses/congenital , Scalp Dermatoses/embryology , Scalp Dermatoses/genetics
15.
Sensors (Basel) ; 16(11)2016 Nov 08.
Article in English | MEDLINE | ID: mdl-27834796

ABSTRACT

The unprecedented growth of today's cities together with increased population mobility are fueling the avalanche in the numbers of vehicles on the roads. This development led to the new challenges for the traffic management, including the mitigation of road congestion, accidents, and air pollution. Over the last decade, researchers have been focusing their efforts on leveraging the recent advances in sensing, communications, and dynamic adaptive technologies to prepare the deployed road traffic management systems (TMS) for resolving these important challenges in future smart cities. However, the existing solutions may still be insufficient to construct a reliable and secure TMS that is capable of handling the anticipated influx of the population and vehicles in urban areas. Along these lines, this work systematically outlines a perspective on a novel modular environment for traffic modeling, which allows to recreate the examined road networks in their full resemblance. Our developed solution is targeted to incorporate the progress in the Internet of Things (IoT) technologies, where low-power, embedded devices integrate as part of a next-generation TMS. To mimic the real traffic conditions, we recreated and evaluated a practical traffic scenario built after a complex road intersection within a large European city.

16.
Development ; 143(12): 2206-16, 2016 06 15.
Article in English | MEDLINE | ID: mdl-27302397

ABSTRACT

The neural crest (NC) is crucial for the evolutionary diversification of vertebrates. NC cells are induced at the neural plate border by the coordinated action of several signaling pathways, including Wnt/ß-catenin. NC cells are normally generated in the posterior neural plate border, whereas the anterior neural fold is devoid of NC cells. Using the mouse model, we show here that active repression of Wnt/ß-catenin signaling is required for maintenance of neuroepithelial identity in the anterior neural fold and for inhibition of NC induction. Conditional inactivation of Tcf7l1, a transcriptional repressor of Wnt target genes, leads to aberrant activation of Wnt/ß-catenin signaling in the anterior neuroectoderm and its conversion into NC. This reduces the developing prosencephalon without affecting the anterior-posterior neural character. Thus, Tcf7l1 defines the border between the NC and the prospective forebrain via restriction of the Wnt/ß-catenin signaling gradient.


Subject(s)
Cell Lineage , Neural Crest/cytology , Transcription Factor 7-Like 1 Protein/metabolism , Zebrafish Proteins/metabolism , Animals , Biomarkers/metabolism , Cell Transdifferentiation , Gene Deletion , Humans , Integrases/metabolism , Mice, Transgenic , Neural Crest/metabolism , Neural Tube Defects/metabolism , Neural Tube Defects/pathology , Phenotype , Prosencephalon/embryology , Prosencephalon/metabolism , Repressor Proteins/metabolism , Transcription Factor AP-2/metabolism , Wnt Signaling Pathway , Zebrafish/metabolism , beta Catenin/metabolism
17.
BMC Dev Biol ; 15: 40, 2015 Nov 06.
Article in English | MEDLINE | ID: mdl-26545946

ABSTRACT

BACKGROUND: TALE-class homeodomain transcription factors Meis and Pbx play important roles in formation of the embryonic brain, eye, heart, cartilage or hematopoiesis. Loss-of-function studies of Pbx1, 2 and 3 and Meis1 documented specific functions in embryogenesis, however, functional studies of Meis2 in mouse are still missing. We have generated a conditional allele of Meis2 in mice and shown that systemic inactivation of the Meis2 gene results in lethality by the embryonic day 14 that is accompanied with hemorrhaging. RESULTS: We show that neural crest cells express Meis2 and Meis2-defficient embryos display defects in tissues that are derived from the neural crest, such as an abnormal heart outflow tract with the persistent truncus arteriosus and abnormal cranial nerves. The importance of Meis2 for neural crest cells is further confirmed by means of conditional inactivation of Meis2 using crest-specific AP2α-IRES-Cre mouse. Conditional mutants display perturbed development of the craniofacial skeleton with severe anomalies in cranial bones and cartilages, heart and cranial nerve abnormalities. CONCLUSIONS: Meis2-null mice are embryonic lethal. Our results reveal a critical role of Meis2 during cranial and cardiac neural crest cells development in mouse.


Subject(s)
Cranial Nerves/embryology , Heart/embryology , Homeodomain Proteins/genetics , Neural Crest/embryology , Skull/embryology , Animals , Cartilage/abnormalities , Cartilage/embryology , Forkhead Transcription Factors/biosynthesis , Forkhead Transcription Factors/genetics , Heart Defects, Congenital/embryology , Heart Defects, Congenital/genetics , Hemorrhage/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Neural Crest/metabolism , Repressor Proteins/biosynthesis , Repressor Proteins/genetics , SOX9 Transcription Factor/biosynthesis , SOX9 Transcription Factor/genetics , Skull/innervation
18.
Biochim Biophys Acta ; 1852(5): 839-50, 2015 May.
Article in English | MEDLINE | ID: mdl-25558817

ABSTRACT

Aberrant fibroblast growth factor (FGF) signaling disturbs chondrocyte differentiation in skeletal dysplasia, but the mechanisms underlying this process remain unclear. Recently, FGF was found to activate canonical WNT/ß-catenin pathway in chondrocytes via Erk MAP kinase-mediated phosphorylation of WNT co-receptor Lrp6. Here, we explore the cellular consequences of such a signaling interaction. WNT enhanced the FGF-mediated suppression of chondrocyte differentiation in mouse limb bud micromass and limb organ cultures, leading to inhibition of cartilage nodule formation in micromass cultures, and suppression of growth in cultured limbs. Simultaneous activation of the FGF and WNT/ß-catenin pathways resulted in loss of chondrocyte extracellular matrix, expression of genes typical for mineralized tissues and alteration of cellular shape. WNT enhanced the FGF-mediated downregulation of chondrocyte proteoglycan and collagen extracellular matrix via inhibition of matrix synthesis and induction of proteinases involved in matrix degradation. Expression of genes regulating RhoA GTPase pathway was induced by FGF in cooperation with WNT, and inhibition of the RhoA signaling rescued the FGF/WNT-mediated changes in chondrocyte cellular shape. Our results suggest that aberrant FGF signaling cooperates with WNT/ß-catenin in suppression of chondrocyte differentiation.


Subject(s)
Cartilage/drug effects , Cell Differentiation/drug effects , Chondrocytes/drug effects , Fibroblast Growth Factors/pharmacology , Receptors, Fibroblast Growth Factor/metabolism , Wnt Proteins/metabolism , beta Catenin/metabolism , Animals , Blotting, Western , Cartilage/cytology , Cartilage/metabolism , Cell Differentiation/genetics , Cell Line, Tumor , Cells, Cultured , Chondrocytes/metabolism , Drug Synergism , Fibroblast Growth Factor 2/pharmacology , HEK293 Cells , Humans , Limb Buds/drug effects , Limb Buds/embryology , Limb Buds/metabolism , Low Density Lipoprotein Receptor-Related Protein-6/genetics , Low Density Lipoprotein Receptor-Related Protein-6/metabolism , Microscopy, Confocal , Models, Biological , Rats , Receptors, Fibroblast Growth Factor/genetics , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Signal Transduction/genetics , Transcriptome/drug effects , Transcriptome/genetics , Wnt Proteins/genetics , Wnt Proteins/pharmacology , Wnt3A Protein/pharmacology , beta Catenin/genetics
19.
J Biol Chem ; 289(2): 1128-41, 2014 Jan 10.
Article in English | MEDLINE | ID: mdl-24265322

ABSTRACT

ß-Arrestin is a scaffold protein that regulates signal transduction by seven transmembrane-spanning receptors. Among other functions it is also critically required for Wnt/ß-catenin signal transduction. In the present study we provide for the first time a mechanistic basis for the ß-arrestin function in Wnt/ß-catenin signaling. We demonstrate that ß-arrestin is required for efficient Wnt3a-induced Lrp6 phosphorylation, a key event in downstream signaling. ß-Arrestin regulates Lrp6 phosphorylation via a novel interaction with phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2)-binding protein Amer1/WTX/Fam123b. Amer1 has been shown very recently to bridge Wnt-induced and Dishevelled-associated PtdIns(4,5)P2 production to the phosphorylation of Lrp6. Using fluorescence recovery after photobleaching we show here that ß-arrestin is required for the Wnt3a-induced Amer1 membrane dynamics and downstream signaling. Finally, we show that ß-arrestin interacts with PtdIns kinases PI4KIIα and PIP5KIß. Importantly, cells lacking ß-arrestin showed higher steady-state levels of the relevant PtdInsP and were unable to increase levels of these PtdInsP in response to Wnt3a. In summary, our data show that ß-arrestins regulate Wnt3a-induced Lrp6 phosphorylation by the regulation of the membrane dynamics of Amer1. We propose that ß-arrestins via their scaffolding function facilitate Amer1 interaction with PtdIns(4,5)P2, which is produced locally upon Wnt3a stimulation by ß-arrestin- and Dishevelled-associated kinases.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Arrestins/metabolism , Cell Membrane/metabolism , Low Density Lipoprotein Receptor-Related Protein-6/metabolism , Tumor Suppressor Proteins/metabolism , Wnt3A Protein/metabolism , Adaptor Proteins, Signal Transducing/genetics , Animals , Arrestins/genetics , Blotting, Western , Cells, Cultured , Dishevelled Proteins , Embryo, Mammalian/cytology , Fibroblasts/cytology , Fibroblasts/metabolism , HEK293 Cells , Humans , Low Density Lipoprotein Receptor-Related Protein-6/genetics , Mice , Mice, Knockout , Microscopy, Confocal , Minor Histocompatibility Antigens , Phosphatidylinositol 4,5-Diphosphate/metabolism , Phosphoproteins/genetics , Phosphoproteins/metabolism , Phosphorylation , Phosphotransferases (Alcohol Group Acceptor)/genetics , Phosphotransferases (Alcohol Group Acceptor)/metabolism , Protein Binding , RNA Interference , Tumor Suppressor Proteins/genetics , Wnt3A Protein/genetics , beta-Arrestins
20.
Ultrasound Med Biol ; 39(10): 1887-902, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23849387

ABSTRACT

This article describes a novel method for highly accurate and effective localization of the transverse section of the carotis comunis artery in ultrasound images. The method has a high success rate, approximately 97%. Unlike analytical methods based on geometric descriptions of the object sought, the method proposed here can cover a large area of shape variation of the artery under study, which normally occurs during examinations as a result of the pressure on the examined tissue, tilt of the probe, setup of the sonographic device, and other factors. This method shows great promise in automating the process of determining circulatory system parameters in the non-invasive clinical diagnostics of cardiovascular diseases. The method employs a Viola-Jones detector that has been specially adapted for efficient detection of transverse sections of the carotid artery. This algorithm is trained on a set of labeled images using the AdaBoost algorithm, Haar-like features and the Matthews coefficient. The training algorithm of the artery detector was modified using evolutionary algorithms. The method for training a cascade of classifiers achieves on a small number of positive and negative training data samples (about 500 images) a high success rate in a computational time that allows implementation of the detector in real time. Testing was performed on images of different patients for whom different ultrasonic instruments were used under different conditions (settings) so that the algorithm developed is applicable in general radiologic practice.


Subject(s)
Algorithms , Carotid Arteries/diagnostic imaging , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Pattern Recognition, Automated/methods , Ultrasonography/methods , Artificial Intelligence , Computer Systems , Humans , Reproducibility of Results , Sensitivity and Specificity , Software
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