Search results for "Extracellular Matrix"

Hyperplastic Conotruncal Endocardial Cushions and Transposition of Great Arteries in Perlecan-Null Mice

2002

Perlecan is a heparan-sulfate proteoglycan abundantly expressed in pericellular matrices and basement membranes during development. Inactivation of the perlecan gene in mice is lethal at two developmental stages: around E10 and around birth. We report a high incidence of malformations of the cardiac outflow tract in perlecan-deficient embryos. Complete transposition of great arteries was diagnosed in 11 out of 15 late embryos studied (73%). Three of these 11 embryos also showed malformations of semilunar valves. Mesenchymal cells in the outflow tract were abnormally abundant in mutant embryos by E9.5, when the endocardial-mesenchymal transformation starts in wild-type embryos. At E10.5, mut…

Evolution of Cell Adhesion Systems: Evidence for Arg-Gly-Asp-Mediated Adhesion in the Protozoan Neoparamoeba aestuarina

1995

Developmental processes in multicellular organisms require structural elements, such as adhesion molecules, to stabilize cells at functional positions. In vertebrates, a series of extracellular matrix proteins, e.g. fibronectin and laminin, are involved in cell adhesion. These proteins contain Arg-Gly-Asp [RGD] at their binding sites. Here we show that at concentrations above 2 mM the peptide GRGDSPK, comprising the tripeptide RGD (Arg-Gly-Asp), prevents the adhesiveness of cells of the marine amoeba Neoparamoeba aestuarina. In addition, elevated levels of GRGDSPK cause cells to alter their shapes from those with digitiform subpseudopodia to rounded cells with small lobed pseudopodia. These…

Cajal–Retzius and Subplate Cells

2013

The laminar and columnar organization of the mature cerebral cortex is determined by a variety of early developmental processes. Two distinct populations of early generated preplate neurons play key roles in corticogenesis. Cajal–Retzius neurons, located in the marginal zone (later layer I), control the formation of neocortical layers by releasing the extracellular matrix protein reelin, which serves as a guiding signal for migrating neurons. Subplate neurons in the lower neocortical layer play an active role in transient synaptic circuits and influence early cortical plasticity and the maturation of the columnar architecture. Both neuronal cell populations serve as transient synaptic targe…

Feedback Mechanisms between ?2M and TGF?1 Reduce Extracellular Matrix Synthesis of Liver Fat-Storing Cells

1994

The Origin of Metazoan Complexity: Porifera as Integrated Animals

2011

SYNOPSIS. Sponges [Porifera] are the phylogenetically oldest metazoan phylum still extant today; they share the closest relationship with the hypothetical common metazoan ancestor, the Urmetazoa. During the past 8 years cDNAs coding for proteins involved in cell-cell- and cell-tissue interaction have been cloned from sponges, primarily from Suberites domuncula and Geodia cydonium and their functions have been studied in vivo as well as in vitro. Also, characteristic elements of the extracellular matrix have been identified and cloned. Those data confirmed that all metazoan phyla originate from one ancestor, the Urmetazoa. The existence of cell adhesion molecules allowed the emergence of a c…

DSD-1-Proteoglycan/Phosphacan and Receptor Protein Tyrosine Phosphatase-Beta Isoforms during Development and Regeneration of Neural Tissues

2007

Interactions between neurons and glial cells play important roles in regulating key events of development and regeneration of the CNS. Thus, migrating neurons are partly guided by radial glia to their target, and glial scaffolds direct the growth and directional choice of advancing axons, e.g., at the midline. In the adult, reactive astrocytes and myelin components play a pivotal role in the inhibition of regeneration. The past years have shown that astrocytic functions are mediated on the molecular level by extracellular matrix components, which include various glycoproteins and proteoglycans. One important, developmentally regulated chondroitin sulfate proteoglycan is DSD-1-PG/phosphacan,…

Synthetic/ECM-inspired hybrid platform for hollow microcarriers with ROS-triggered nanoporation hallmarks

2017

Reactive oxygen species (ROS) are key pathological signals expressed in inflammatory diseases such as cancer, ischemic conditions and atherosclerosis. An ideal drug delivery system should not only be responsive to these signals but also should not elicit an unfavourable host response. This study presents an innovative platform for drug delivery where a natural/synthetic composite system composed of collagen type I and a synthesized polythioether, ensures a dual stimuli-responsive behaviour. Collagen type I is an extracellular matrix constituent protein, responsive to matrix metalloproteinases (MMP) cleavage per se. Polythioethers are stable synthetic polymers characterized by the presence o…

Relationships Between Dimorphism, Cell Wall Structure, and Surface Activities in Candida albicans

1991

Most cells are covered with a complex network of interacting molecules that form the extracellular matrix. These molecules (proteins and polysaccharides) are secreted locally and interact among themselves to form an organized structure outside the cell plasma membrane. In unicellular eukaryotic organisms and plant cells, this structure is reinforced to withstand osmotic changes in the external environment, giving rise to the so-called cell wall.

Glycoconjugate expression and cartilage development of the cranial skeleton.

1998

Only few detailed investigations have focused on the glycobiology of cranial development. The functional elements in most inductive and morphogenetic processes are not individual cells, but rather collectives of interacting populations and extracellular matrix components that give rise to specific tissues and organs. Experimental evidence strongly suggests that sugar chains not only confer morphological characteristics. Complex carbohydrate molecules and their corresponding receptors are involved in recognition processes decoding biological information during cranial morphogenesis. The distribution patterns of glycoconjugates are highly dynamic and show a clear correlation with characterist…

In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration

2012

A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…