The Photocatalytic Activity of the Bi2O3-B2O3-ZnO-TiO2 Glass Coating

Due to the low melting temperature, the glazes based on the Bi2O3-B2O3-ZnO system are used as coatings on the surface of industrial glass substrates. Moreover, the composition of these coatings does not contain PbO, meeting the optical and environmental properties requirements. In this study, TiO2 was used in the Bi2O3-B2O3-ZnO glaze system to improve its photocatalytic ability. This can be considered a four – component glass system Bi2O3-B2O3-ZnO-TiO2. The heating microscopy results show that the melting temperature of the glaze system is 606 °C. The Fourier transform infrared spectroscopy results show that the TiO2 polyhedra are located independently in the structure without participating in forming a glass network. Thanks to that, the photocatalytic properties of TiO2 are maintained. The X-ray diffraction patterns results show that the formed TiO2 nanocrystals are rutile and anatase crystals. The results of determining the band gap energy using UV-Vis show that the band gap energy of the base glaze system increases with the addition of TiO2. The methylene blue decomposition results also showed that the ability to decompose organic increased when TiO2 was added to the glaze coating. The characteristics such as melting temperature, microstructure, and photocatalytic capacity of Bi2O3-B2O3-ZnO-TiO2 white glazes (5 and 10 % weight of TiO2) also were indicated in this paper

Fibroblast Primary Cilia are Required for Cardiac Fibrosis

Background: The primary cilium is a singular cellular structure that extends from the surface of many cell types and plays crucial roles in vertebrate development, including that of the heart. Whereas ciliated cells have been described in developing heart, a role for primary cilia in adult heart has not been reported. This, coupled with the fact that mutations in genes coding for multiple ciliary proteins underlie polycystic kidney disease, a disorder with numerous cardiovascular manifestations, prompted us to identify cells in adult heart harboring a primary cilium and to determine whether primary cilia play a role in disease-related remodeling. Methods: Histological analysis of cardiac tissues from C57BL/6 mouse embryos, neonatal mice, and adult mice was performed to evaluate for primary cilia. Three injury models (apical resection, ischemia/reperfusion, and myocardial infarction) were used to identify the location and cell type of ciliated cells with the use of antibodies specific for cilia (acetylated tubulin, γ-tubulin, polycystin [PC] 1, PC2, and KIF3A), fibroblasts (vimentin, α-smooth muscle actin, and fibroblast-specific protein-1), and cardiomyocytes (α-actinin and troponin I). A similar approach was used to assess for primary cilia in infarcted human myocardial tissue. We studied mice silenced exclusively in myofibroblasts for PC1 and evaluated the role of PC1 in fibrogenesis in adult rat fibroblasts and myofibroblasts. Results: We identified primary cilia in mouse, rat, and human heart, specifically and exclusively in cardiac fibroblasts. Ciliated fibroblasts are enriched in areas of myocardial injury. Transforming growth factor β-1 signaling and SMAD3 activation were impaired in fibroblasts depleted of the primary cilium. Extracellular matrix protein levels and contractile function were also impaired. In vivo, depletion of PC1 in activated fibroblasts after myocardial infarction impaired the remodeling response. Conclusions: Fibroblasts in the neonatal and adult heart harbor a primary cilium. This organelle and its requisite signaling protein, PC1, are required for critical elements of fibrogenesis, including transforming growth factor β-1-SMAD3 activation, production of extracellular matrix proteins, and cell contractility. Together, these findings point to a pivotal role of this organelle, and PC1, in disease-related pathological cardiac remodeling and suggest that some of the cardiovascular manifestations of autosomal dominant polycystic kidney disease derive directly from myocardium-autonomous abnormalities

A calcineurin–Hoxb13 axis regulates growth mode of mammalian cardiomyocytes

10.1038/s41586-020-2228-6Nature5827811271-27

Palladin-depleted myoblasts induce p21 expression and decrease Caspase7-dependent apoptosis.

<p><b>(A)</b> qPCR analysis of p21 was performed to assess the expression of cell cycle withdraw marker in control and palladin-knockdown cells. <b>(B)</b> Time course of the apoptosis quantification in palladin-knockdown and control cells measured using Caspase-Glo 3/7 luminescence assay. <b>(C)</b> Time course of palladin-knockdown and control cells survival measured using MTT assay. <b>(D)</b> Time course of the apoptosis quantification in palladin-knockdown and control cells measured using Caspase-7 immunofluorescence assay. All data represent at least three independent experiments. Values are presented as the means ± SD. * indicates statistically significant difference from control cells, * <i>p<</i>0.05, ** <i>p<</i>0.01, *** <i>p<</i>0.001 by two-way ANOVA (A, C) or Student’s <i>t</i>-test (B, D).</p

Effect of palladin overexpression on C2C12 differentiation.

<p><b>(A)</b> Expression of MyHC (red) by immunofluorescence on C2C12 cells transfected with pEGFP (EGFP) or pEGFP-90-kDa palladin, pEGFP-140-kDa palladin, and pEGFP-200-kDa palladin, and differentiated for 5 days. Nuclei are stained with DAPI. Scale bar is 100 μm. Quantifications of <b>(B)</b> fusion index and <b>(C)</b> number of MyHC-positive cells of overexpressed cells. All error bars indicate the means ± SD of at least four independent determinations. * indicates statistically significant difference from control cells, * p<0.05, ** p<0.01, *** p<0.001 by Student’s t-test, ns = not significant). <b>(D)</b> Quantification of multinucleated myotubes throughout the course of differentiation. Scale bar is 100 μm.</p

Schematic model outlining how reduced expression of palladin affects skeletal muscle differentiation processes.

<p>Schematic diagram showing the involvement of palladin in differentiation of proliferating myoblasts into nascent myotubes and maturation into myofibers. <b>(A)</b> Expression of palladin isoforms during myogenesis. 140-kDa palladin is decreased while 90- and 200-kDa palladin are increased. <b>(B)</b> In the early stage of differentiation, 140-kDa palladin might promote myoblast proliferation and prevent entry into the differentiation program via the inhibition of p21 activity. Thus, the depletion of palladin promotes cell cycle exit, decreases apoptosis and activates myogenic regulatory factors, especially myogenin and MyHC, allowing myoblasts to start their differentiation program. <b>(C)</b> In late differentiation, 90- and 200-kDa palladin might increase the myogenic index through the inhibition of myostatin activity, promoting the formation of mature myotubes. Thus, knockdown of palladin releases myostatin, which results in the formation of thinner myotubes in palladin-depleted cells.</p

Effect of palladin depletion on terminal differentiation of C2C12 cells.

<p><b>(A)</b> Phase contrast images of stable transfectants at late stages of differentiation. Scale bar is 50 μm. <b>(B)</b> Representative immunofluorescence images of stable transfectants at day 5 of differentiation. Cells were labeled with palladin (red), MyHC (green), and DAPI (blue). Scale bar is 100 μm. <b>(C)</b> Fusion index analysis of stable transfectants at day 5 (left) and day 7 (right) of differentiation. A minimum of 4,000 nuclei were counted from random fields of each cell line. Note that palladin depletion resulted in a decrease of the fusion index at the late stage of differentiation. <b>(D)</b> Quantification of multinucleated myotubes throughout the course of differentiation. <b>(E)</b> Quantification of the number of MyHC-positive cells in stable transfectants. All error bars indicate the means ± SD of at least four independent experiments. * indicates statistically significant difference from control cells, * <i>p<</i>0.05, ** <i>p<</i>0.01, *** <i>p<</i>0.001 by Student’s <i>t</i>-test. <i>ns</i> = not significant.</p

Loss of palladin expression results in increased myostatin activity.

<p>Quantification of myotube <b>(A)</b> width and <b>(B)</b> length of stable transfectants at late-stage differentiation (day 5 and day 7). qPCR was performed to assess the expression of <b>(C)</b> myostatin and <b>(E)</b> IGF-1 during myoblast differentiation. <b>(D)</b> Western blots analysis of palladin-knockdown and control cells labeled with an antibody against active myostatin. All error bars indicate the means ± SD of at least three independent determinations. * indicates statistically significant difference from control cells,* p<0.05, ** p<0.01, *** p<0.001 by Student’s t-test (A, B) or two-way ANOVA (C, E). ns = not significant.</p

Decrease of cell migration in C2C12 myoblasts by palladin knockdown.

<p><b>(A)</b> The wound-healing migration of stable transfectants was recorded with an optical microscope at the indicated time points and subjected to statistical analysis (n = 4 per group). The results are represented as the percentage of cell-covered area (lower panel). <b>(B)</b> The stable transfectants were plated onto the upper chamber of transwells (n = 6 per group). After 12 h, myoblasts that migrated to the bottom side of the filter were stained with crystal violet and counted (lower panel). The data were evaluated from at least three independent experiments. Values are presented as the means ± SD. * indicates statistically significant difference from control cells, *p<0.05, **p<0.01 by Student’s t-test. Scale bar is 100 μm.</p

Dual Roles of Palladin Protein in <i>In Vitro</i> Myogenesis: Inhibition of Early Induction but Promotion of Myotube Maturation

<div><p>Palladin is a microfilament-associated phosphoprotein whose function in skeletal muscle has rarely been studied. Therefore, we investigate whether myogenesis is influenced by the depletion of palladin expression known to interfere with the actin cytoskeleton dynamic required for skeletal muscle differentiation. The inhibition of palladin in C2C12 myoblasts leads to precocious myogenic differentiation with a concomitant reduction in cell apoptosis. This premature myogenesis is caused, in part, by an accelerated induction of p21, myogenin, and myosin heavy chain, suggesting that palladin acts as a negative regulator in early differentiation phases. Paradoxically, palladin-knockdown myoblasts are unable to differentiate terminally, despite their ability to perform some initial steps of differentiation. Cells with attenuated palladin expression form thinner myotubes with fewer myonuclei compared to those of the control. It is noteworthy that a negative regulator of myogenesis, myostatin, is activated in palladin-deficient myotubes, suggesting the palladin-mediated impairment of late-stage myogenesis. Additionally, overexpression of 140-kDa palladin inhibits myoblast differentiation while 200-kDa and 90-kDa palladin-overexpressed cells display an enhanced differentiation rate. Together, our data suggest that palladin might have both positive and negative roles in maintaining the proper skeletal myogenic differentiation <i>in vitro</i>.</p></div