Biological relevance of receptor protein tyrosine phosphatase beta/zeta (RPTPβ\beta/ζ\zeta) isoforms in the developing mouse visual system

"Entwicklung" ist ein abstrakter Begriff, der ein natürliches und zugleich faszinierendes Phänomen umschreibt. Dieser Prozess verlangt nach einer präzisen Regulation durch einen kontinuierlichen Austausch durch Zell-Zell Kontakte in Kooperation mit dem externen Milieu. Diese Studie befasste sich mit der zellulären Expression und biologischen Relevanz der extrazellulären Matrix Moleküle Phosphacan/RPTP$\beta$/$\zeta$ und Tenascin C (Tnc) während der embryonalen Retinogenese und untersuchte, ob der Transkriptionsfaktor Pax6 die Ausführung der Funktionen vermittelt. Die Resultate verdeutlichten, dass Tnc, CS-Ketten und Pax6 die Proliferation von Vorläuferzellen und den Übergang in einen neurogenen Status beeinflussen. Die Differenzierung von Neuronen könnte diese "Trio" direkt oder indirekt zusammen agieren. Eine Einschränkung der Interaktion führte in allen Modelsystem zu einer erhöhten Neurogenese Unter physiologischen Bedingungen wird ein vorzeitiger Einsatz der Differenzierung inhibiert

Characterization of the Human Plasma Biofilm Model (hpBIOM) to Identify Potential Therapeutic Targets for Wound Management of Chronic Infections

The treatment of chronic wounds still represents a major challenge in wound management. Recent estimates suggest that 60–80% of chronic wounds are colonized by pathogenic microorganisms, which are strongly considered to have a major inhibiting influence on the healing process. By means of an innovative biofilm model based on human plasma, the time-dependent behavior of various bacterial strains under wound-milieu-like conditions were investigated, and the growth habits of different cocci species were compared. Undescribed fusion events between colonies of MRSA as well as of Staphylococcus epidermidis were detected, which were associated with the remodeling and reorganization of the glycocalyx of the wound tissue. After reaching a maximum colony size, the spreading of individual bacteria was observed. Interestingly, the combination of different cocci species with Pseudomonas aeruginosa in the human plasma biofilm revealed partial synergistic effects in these multispecies organizations. RT-qPCR analyses gave a first impression of the relevant proteins involved in the formation and maturation of biofilms, especially the role of fibrinogen-binding proteins. Knowledge of the maturation and growth behavior of persistent biofilms investigated in a translational human biofilm model reflects a starting point for the development of novel tools for the treatment of chronic wounds

Monitoring wound healing in a 3D wound model by hyperspectral imaging and efficient clustering.

Wound healing is a complex and dynamic process with different distinct and overlapping phases from homeostasis, inflammation and proliferation to remodelling. Monitoring the healing response of injured tissue is of high importance for basic research and clinical practice. In traditional application, biological markers characterize normal and abnormal wound healing. Understanding functional relationships of these biological processes is essential for developing new treatment strategies. However, most of the present techniques (in vitro or in vivo) include invasive microscopic or analytical tissue sampling. In the present study, a non-invasive alternative for monitoring processes during wound healing is introduced. Within this context, hyperspectral imaging (HSI) is an emerging and innovative non-invasive imaging technique with different opportunities in medical applications. HSI acquires the spectral reflectance of an object, depending on its biochemical and structural characteristics. An in-vitro 3-dimensional (3-D) wound model was established and incubated without and with acute and chronic wound fluid (AWF, CWF), respectively. Hyperspectral images of each individual specimen of this 3-D wound model were assessed at day 0/5/10 in vitro, and reflectance spectra were evaluated. For analysing the complex hyperspectral data, an efficient unsupervised approach for clustering massive hyperspectral data was designed, based on efficient hierarchical decomposition of spectral information according to archetypal data points. It represents, to the best of our knowledge, the first application of an advanced Data Mining approach in context of non-invasive analysis of wounds using hyperspectral imagery. By this, temporal and spatial pattern of hyperspectral clusters were determined within the tissue discs and among the different treatments. Results from non-invasive imaging were compared to the number of cells in the various clusters, assessed by Hematoxylin/Eosin (H/E) staining. It was possible to correlate cell quantity and spectral reflectance during wound closure in a 3-D wound model in vitro

Elevating Endogenous Sphingosine-1-Phosphate (S1P) Levels Improves Endothelial Function and Ameliorates Atherosclerosis in Low Density Lipoprotein Receptor-Deficient (LDL-R-/-) Mice

Background Sphingosine-1-phosphate (S1P) is a bioactive lysosphingolipid and a constituent of high-density lipoprotein (HDL) exerting several atheroprotective effects in vitro. However, the few studies addressing anti-atherogenic effects of S1P in vivo have led to disparate results. We here examined atherosclerosis development in low-density lipoprotein receptor (LDL-R)-deficient (LDL-R-/-) mice with elevated endogenous S1P levels. Methods and Results Sub-lethally irradiated LDL-R-/-mice were transplanted with bone marrow deficient in sphingosine kinase 2 (SphK2), which led to the elevation of S1P concentrations in erythrocytes, plasma and HDL by approximately 1.5- to 2.0-fold in SphK2-/-/LDL-R-/-mice. Afterwards, mice were fed a Western diet for 14 weeks. Elevation of endogenous S1P significantly reduced atherosclerotic lesion formation by approximately half without affecting the plasma lipid profile. Furthermore, the macrophage content of atherosclerotic lesions and lipopolysaccharide-induced monocyte recruitment to the peritoneal cavity were reduced in SphK2-/-/LDL-R-/-mice. Studies using intra-vital microscopy revealed that endogenous S1P lowered leukocyte adhesion to capillary wall and decreased endothelial permeability to fluorescently labelled LDL. Moreover, SphK2-/-/LDL-R-/-mice displayed decreased levels of vascular cell adhesion molecule 1 in atherosclerotic lesions and in plasma. Studies in vitro demonstrated reduced monocyte adhesion and transport across an endothelial layer exposed to increasing S1P concentrations, murine plasma enriched in S1P or plasma obtained from SphK2-deficient animals. In addition, decreased permeability to fluorescence-labelled dextran beads or LDL was observed in S1P-treated endothelial cells. Conclusion We conclude that raising endogenous S1P levels exerts anti-atherogenic effects in LDL-R-/-mice that are mediated by favourable modulation of endothelial function

Automated and efficient interpretation of 3D wound models by non-invasive hyperspectral imaging <i>in vitro</i>.

<p>Experimental design and work flow showing the different steps for monitoring wound healing from hyperspectral imaging data to interpretation using an efficient approach for unsupervised classification of wound tissue based on hierarchical decomposition according to archetypal data points.</p

Representative spectra of 3-dimensional wound models.

<p>(a) Cluster representatives after computing of XHC for the hyperspectral image data for. The number of cluster was set to <i>k</i> = 7 that could reflect biological processes in this cell culture system. The corresponding signatures represented different regions of the tissues. The dotted line was produced by a part of the tissue covered with fluid resulting in overexposure during the measurement. (b-c) The quantification of pixel densities per cluster. The y-axis is shown in log scale. AWF and CWF induced no significant differences in pixel densities compared to the control situation, however, the dark blue cluster was absent after 10 days <i>in vitro</i> without any supplements.</p

Histological classification of hyperspectral cluster means in relation to wound healing processes.

<p>(a) H/E staining was performed to monitor the wound healing progress morphologically over a specific time period <i>in vitro</i>. The different stages were presented as false color zoomed images of the hyperspectral clusters for the wounds. (b) The quantification of the cell number in different regions of interests revealed the first time a correlation between spectral reflectance and cell quantity in the tissue. (c) Immunohistochemical investigation of CXCR4, a marker for migratory cells, determined no correlations to reflectance data. Additionally, the cells generating the characteristic hyperspectral signature did not correspond to Caspase 3-expressing apoptotic cells (not shown). Scale bar: 250 <i>μ</i>m.</p

Comparison for Kmeans and XHC for different number of clusters.

<p>With increasing number of clusters, Kmeans resulted in more clusters around the wound as this area represented the major part of the tissue. XHC further highlighted the middle part of the images, which was the result of a hierarchical decomposition of the signatures. This allowed a better investigation and comparison of the wound tissue and healing progress.</p