scholarly journals Hemicentin-1 is An Essential Extracellular Matrix Component of the Dermal-Epidermal and Myotendinous Junctions

2021 ◽  
Author(s):  
Daniela Welcker ◽  
Cornelia Stein ◽  
Natalia Martins Feitosa ◽  
Joy Armistead ◽  
Jin-Li Zhang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Developmental Stages ◽  
Cell Types ◽  
Connective Tissues ◽  
Functional Behavior ◽  
Transmission Electron ◽  
Cellular Microenvironments ◽  
Ecm Architecture ◽  
And Function ◽  
Myotendinous Junctions

Abstract The extracellular matrix (ECM) architecture is composed of supramolecular fibrillar networks that define tissue specific cellular microenvironments. Hemicentins (Hmcn1 and Hmcn2) are ancient and very large members (>600 kDa) of the fibulin family, whose short members are known to guide proper morphology and functional behavior of specialized cell types predominantly in elastic tissues. However, the tissue distribution and function of Hemicentins within the cellular microenvironment of connective tissues has remained largely unknown. Performing in situ hybridization and immunofluorescence analyses, we found that Hmcn1 and Hmcn2 show a complementary distribution throughout different tissues and developmental stages. In postnatal dermal-epidermal junctions (DEJ) and myotendinous junctions (MTJ), Hmcn1 is primarily produced by mesenchymal cells (fibroblasts, tenocytes), Hmcn2 by cells of epithelial origin (keratinocytes, myocytes). Hmcn1-/-mice are viable and show no overt phenotypes in tissue tensile strength and locomotion tests. However, transmission electron microscopy revealed ultrastructural basement membrane (BM) alterations at the DEJ and MTJ of Hmcn1-/-mice, pointing to a thus far unknown role of Hmcn1 for BM and connective tissue boundary integrity.

scholarly journals Hemicentin-1 is an essential extracellular matrix component of the dermal–epidermal and myotendinous junctions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Welcker ◽  
Cornelia Stein ◽  
Natalia Martins Feitosa ◽  
Joy Armistead ◽  
Jin-Li Zhang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Developmental Stages ◽  
Cell Types ◽  
Connective Tissues ◽  
Functional Behavior ◽  
Transmission Electron ◽  
Cellular Microenvironments ◽  
And Function ◽  
Myotendinous Junctions

AbstractThe extracellular matrix architecture is composed of supramolecular fibrillar networks that define tissue specific cellular microenvironments. Hemicentins (Hmcn1 and Hmcn2) are ancient and very large members (> 600 kDa) of the fibulin family, whose short members are known to guide proper morphology and functional behavior of specialized cell types predominantly in elastic tissues. However, the tissue distribution and function of Hemicentins within the cellular microenvironment of connective tissues has remained largely unknown. Performing in situ hybridization and immunofluorescence analyses, we found that mouse Hmcn1 and Hmcn2 show a complementary distribution throughout different tissues and developmental stages. In postnatal dermal–epidermal junctions (DEJ) and myotendinous junctions (MTJ), Hmcn1 is primarily produced by mesenchymal cells (fibroblasts, tenocytes), Hmcn2 by cells of epithelial origin (keratinocytes, myocytes). Hmcn1−/− mice are viable and show no overt phenotypes in tissue tensile strength and locomotion tests. However, transmission electron microscopy revealed ultrastructural basement membrane (BM) alterations at the DEJ and MTJ of Hmcn1−/− mice, pointing to a thus far unknown role of Hmcn1 for BM and connective tissue boundary integrity.

scholarly journals Effects of particulates and lipids on the hydraulic conductivity of Matrigel

2008 ◽  
Vol 105 (2) ◽  
pp. 621-628 ◽  
Author(s):  
William J. McCarty ◽  
Melissa F. Chimento ◽  
Christine A. Curcio ◽  
Mark Johnson
Keyword(s):  
Extracellular Matrix ◽  
Hydraulic Conductivity ◽  
Weight Fraction ◽  
Low Density Lipoproteins ◽  
Blood Vessel Wall ◽  
Connective Tissues ◽  
Rigid Particles ◽  
Ldl Particles ◽  
Transmission Electron ◽  
Theoretical Predictions

The hydraulic conductivity of a connective tissue is determined both by the fine ultrastructure of the extracellular matrix and the effects of larger particles in the interstitial space. In this study, we explored this relationship by examining the effects of 30- or 90-nm-diameter latex nanospheres or low-density lipoproteins (LDL) on the hydraulic conductivity of Matrigel, a basement membrane matrix. The hydraulic conductivity of Matrigel with latex nanospheres or LDL particles added at 4.8% weight fraction was measured and compared with the hydraulic conductivity of Matrigel alone. The LDL-derived lipids in the gel were visualized by transmission electron microscopy and were seen to have aggregated into particles up to 500 nm in size. The addition of these materials to the medium markedly decreased its hydraulic conductivity, with the LDL-derived lipids having a much larger effect than did the latex nanospheres. Debye-Brinkman theory was used to predict the effect of addition of particles to the hydraulic conductivity of the medium. The theoretical predictions matched well with the results from adding latex nanospheres to the medium. However, LDL decreased hydraulic conductivity much more than was predicted by the theory. The validation of the theoretical model for rigid particles embedded in extracellular matrix suggests that it could be used to make predictions about the influence of particulates (e.g., collagen, elastin, cells) on the hydraulic conductivity of the fine filamentous matrix (the proteoglycans) in connective tissues. In addition, the larger-than-predicted effects of lipidlike particles on hydraulic conductivity may magnify the pathology associated with lipid accumulation, such as in Bruch's membrane of the retina during macular degeneration and the blood vessel wall in atherosclerosis.

P0658MATRIX AND FLOW MODULATE GENE EXPRESSION IN A 3D VASCULARISED TUBULE MODEL

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Julie Williams ◽  
Sanlin Robinson ◽  
Babak Alaei ◽  
Kimberly Homan ◽  
Maryam Clausen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Impact Analysis ◽  
Cell Types ◽  
Drug Uptake ◽  
Shear Stresses ◽  
The Matrix ◽  
And Function

Abstract Background and Aims Questions abound regarding the translation of in vitro 2D cell culture systems to the human setting. This is especially true of the kidney in which there is a complex hierarchical structure and a multitude of cell types. While it is well accepted that extracellular matrix plays a large part in directing cellular physiology emerging research has highlighted the importance of shear stresses and flow rates too. To fully recapitulate the normal gene expression and function of a particular renal cell type how important is it to completely reconstitute their in vivo surroundings? Method To answer this question, we have cultured proximal tubular (PT) epithelial cells in a 3-dimensional channel embedded within an engineered extracellular matrix (ECM) under physiological flow that is colocalised with an adjacent channel lined with renal microvascular endothelial cells that mimic a peritubular capillary. Modifications to the system were made to allow up to 12 chips to be run in parallel in an easily handleable form. After a period of maturation under continuous flow, both cell types were harvested for RNAseq analyses. RNA expression data was compared with cells cultured under static 2-dimensional conditions on plastic or the engineered ECM. Additionally, the perfusion of glucose through this 3D vascularised PT model has been investigated in the presence and absence of known diabetes modulating agents. Results PCA of RNAseq data showed that a) static non-coated, b) static matrix-coated and c) flow matrix-coated conditions separated into 3 distinct groups, while cell co-culture had less impact. Analysis of transcriptomic signatures showed that many genes were modulated by the matrix with additional genes influenced under flow conditions. Several of these genes, classified as transporters, are of particular importance when using this model to assess drug uptake and safety implications. Co-culture regulated some interesting genes, but fewer than anticipated. Preliminary experiments are underway to monitor glucose uptake and transport between tubules under different conditions. Conclusion We have developed a medium throughput system in which matrix and flow modulate gene expression. This system can be used to study the physiology of molecular cross-talk between cells. Ongoing analysis will further consider relevance to human physiology.

The extracellular matrix of the central and peripheral nervous systems: structure and function

1988 ◽  
Vol 69 (2) ◽  
pp. 155-170 ◽  
Author(s):  
James T. Rutka ◽  
Gerard Apodaca ◽  
Robert Stern ◽  
Mark Rosenblum
Keyword(s):  
Extracellular Matrix ◽  
Nervous System ◽  
Cell Types ◽  
Structure And Function ◽  
Nervous Systems ◽  
Content Type ◽  
Body Of Knowledge ◽  
Central Nervous Systems ◽  
Biological Adhesive ◽  
And Function

✓ The extracellular matrix (ECM) is the naturally occurring substrate upon which cells migrate, proliferate, and differentiate. The ECM functions as a biological adhesive that maintains the normal cytoarchitecture of different tissues and defines the key spatial relationships among dissimilar cell types. A loss of coordination and an alteration in the interactions between mesenchymal cells and epithelial cells separated by an ECM are thought to be fundamental steps in the development and progression of cancer. Although a substantial body of knowledge has been accumulated concerning the role of the ECM in most other tissues, much less is known of the structure and function of the ECM in the nervous system. Recent experiments in mammalian systems have shown that an increased knowledge of the ECM in the nervous system can lead to a better understanding of complex neurobiological processes under developmental, normal, and pathological conditions. This review focuses on the structure and function of the ECM in the peripheral and central nervous systems and on the importance of ECM macromolecules in axonal regeneration, cerebral edema, and cerebral neoplasia.

Calycinal trichomes in Ipomoea cairica (Convolvulaceae): ontogenesis, structure and functional aspects

2011 ◽  
Vol 59 (1) ◽  
pp. 91 ◽  
Author(s):  
Elder Antônio Sousa Paiva ◽  
Luiza Coutinho Martins
Keyword(s):  
Electron Microscopy ◽  
Developmental Stages ◽  
Glandular Trichomes ◽  
Structure And Function ◽  
Short Stalk ◽  
Transmission Electron ◽  
Functional Aspects ◽  
Acidic Polysaccharides ◽  
Low Humidity ◽  
And Function

The presence of calycinal trichomes in Ipomoea has been neglected, which renders the interpretation of their functions difficult. The present work aims to characterise the structure, as well as the composition of the secretion of calycinal trichomes in Ipomoea cairica, in order to establish a relationship between their structure and function. Samples of floral buds at different developmental stages and sepals from fruits were collected and fixed for study under light as well as under scanning and transmission electron microscopy. The calyx of I. cairica is persistent and presents glandular trichomes which produce acidic polysaccharides. The trichomes are peltate and consist of a short stalk and a pluricellular secretory portion. The cells from the secretory portion contain a dense and organelle-rich cytoplasm. The fresh secretion is hyaline and fluid, but solidifies when exposed to low humidity, taking on a crystalline and fragile aspect, and they return to a gel state when in the presence of water. The calycinal trichomes in I. cairica show great structural and ultrastructural similarities to colleters and can be considered functionally analogous. The secretion, which is highly hygroscopic, spreads along the surface of the corolla and of the fruit, apparently protecting these structures against desiccation.

scholarly journals Viscoelasticity Acts as a Marker for Tumor Extracellular Matrix Characteristics

2021 ◽  
Vol 9 ◽  
Author(s):  
Claudia Tanja Mierke
Keyword(s):  
Extracellular Matrix ◽  
Cancer Progression ◽  
Cell Types ◽  
Cellular Behavior ◽  
Matrix Mechanics ◽  
Cancer Types ◽  
And Function ◽  
Different Cell Types ◽  
Further Development ◽  
Functional Phenotype

Biological materials such as extracellular matrix scaffolds, cancer cells, and tissues are often assumed to respond elastically for simplicity; the viscoelastic response is quite commonly ignored. Extracellular matrix mechanics including the viscoelasticity has turned out to be a key feature of cellular behavior and the entire shape and function of healthy and diseased tissues, such as cancer. The interference of cells with their local microenvironment and the interaction among different cell types relies both on the mechanical phenotype of each involved element. However, there is still not yet clearly understood how viscoelasticity alters the functional phenotype of the tumor extracellular matrix environment. Especially the biophysical technologies are still under ongoing improvement and further development. In addition, the effect of matrix mechanics in the progression of cancer is the subject of discussion. Hence, the topic of this review is especially attractive to collect the existing endeavors to characterize the viscoelastic features of tumor extracellular matrices and to briefly highlight the present frontiers in cancer progression and escape of cancers from therapy. Finally, this review article illustrates the importance of the tumor extracellular matrix mechano-phenotype, including the phenomenon viscoelasticity in identifying, characterizing, and treating specific cancer types.

The pigmentary system of developing axolotls

Development ◽  
1984 ◽  
Vol 81 (1) ◽  
pp. 105-125
Author(s):  
S. K. Frost ◽  
L. G. Epp ◽  
S. J. Robinson
Keyword(s):  
Developmental Stages ◽  
Pigment Cell ◽  
Cell Types ◽  
Ambystoma Mexicanum ◽  
Pigment Cells ◽  
Wild Type ◽  
Cell Type ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Mutant Phenotypes

A biochemical and transmission electron microscopic description of the wild-type pigment phenotype in developing Mexican axolotls (Ambystoma mexicanum) is presented. There are three pigment cell types found in adult axolotl skin - melanophores, xanthophores and iridophores. Both pigments and pigment cells undergo specific developmental changes in axolotls. Melanophores are the predominant pigment cell type throughout development; xanthophores occur secondarily and in fewer numbers than melanophores; iridophores do not appear until well into the larval stage and remain thereafter as the least frequently encountered pigment cell type. Ultrastructural differences in xanthophore organelle (pterinosome) structure at different developmental stages correlate with changes in the pattern of pteridine biosynthesis. Sepiapterin, a yellow pteridine, is present in larval axolotl skin but not in adults. Ribofiavin (also yellow) is present in minimal quantities in larval skin and large quantities in adult axolotl skin. Pterinosomes undergo a morphological “reversion” at some point prior to or shortly after axolotls attain sexual maturity. Correlated with the neotenic state of the axolotl, certain larval pigmentary features are retained throughout development. Notably, the pigment cells remain scattered in the dermis such that no two pigment cell bodies overlap, although cell processes may overlap. This study forms the basis for comparison of the wild type pigment phenotype to the three mutant phenotypes-melanoid, axanthic and albino-found in the axolotl.

The acellular stroma of the chick cornea inhibits melanogenesis of the neural-crest-derived cells that colonize it.

Development ◽  
1985 ◽  
Vol 86 (1) ◽  
pp. 143-154
Author(s):  
Steven Campbell ◽  
Jonathan B. L. Bard
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Extracellular Matrix ◽  
Neural Crest ◽  
Corneal Stroma ◽  
Cell Types ◽  
Brown Pigment ◽  
Transmission Electron ◽  
Wide Range

Neural crest (NC) cells from the periorbital mesenchyme (POM) invade the acellular stroma of the chick cornea at stage 27 of development (∼6 days). The invading cells become collagenproducing fibroblasts while the NC cells remaining in the POM differentiate into a wide range of cell types, the most easily recognizable of which is the pigment-producing melanocyte. In this paper, we report observations on the differentiation in vitro of cells within and migrating from explants of corneal stroma and compare their behaviour with that of cells within and migrating from explants of the POM. In ∼70% of cases, POM explants produced black, eumelanin pigmentation within 2–3 days in culture and gave rise to a mixed outgrowth of fibroblasts and melanoblasts that produced brown pigment. In no case, however, did a corneal explant produce black pigment (so demonstrating that any POM contamination was negligible). However, in 28% of cultures from stage-27 and -28 corneas, some of the cells in the outgrowth contained brown pigment indistinguishable from that produced by the POM control, although the majority of the cells in each case were fibroblasts. Two lines of investigation demonstrated that this pigment was melanin: first, transmission electron microscopy showed that the pigment organelles were incompletely melanized, granular melanosomes; second, tests designed to demonstrate the presence of lipofuscin, an alternative pigment, proved negative. Migrating cells from older corneas, in contrast, showed no evidence of even the first stages of melanogenesis. These results show, first, that some of the NC cells that invade the cornea are at least bipotent and hence representative of the POM population rather than being a unique subgroup and, second, that the acellular stroma of the cornea determines the state of differentiation of the NC cells that colonize it. The results thus provide an unequivocal demonstration that extracellular matrix can induce postmigratory NC cells to differentiate into fibroblasts.

Evaluation of SmartFlare probe applicability for verification of RNAs in early equine conceptuses, equine dermal fibroblast cells and trophoblastic vesicles

2017 ◽  
Vol 29 (11) ◽  
pp. 2157 ◽  
Author(s):  
S. Budik ◽  
W. Tschulenk ◽  
S. Kummer ◽  
I. Walter ◽  
C. Aurich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Particle ◽  
Developmental Stages ◽  
Cultured Cells ◽  
Dermal Fibroblast ◽  
Fibroblast Cell ◽  
Cell Types ◽  
Limited Information ◽  
Transmission Electron

Live cell RNA imaging has become an important tool for studying RNA localisation, dynamics and regulation in cultured cells. Limited information is available using these methods in more complex biological systems, such as conceptuses at different developmental stages. So far most of the approaches rely on microinjection of synthetic constructs into oocytes during or before fertilisation. Recently, a new generation of RNA-specific probes has been developed, the so named SmartFlare probes (Merck Millipore). These consist of a central 15-nm gold particle with target-specific DNAs immobilised on its surface. Because of their central gold particle, SmartFlare probes are detectable by transmission electron microscopy. The aim of the present study was to investigate the uptake and distribution of SmartFlare probes in equine conceptuses at developmental stages suitable for embryo transfer (Days 6–10), equine trophoblast vesicles and equine dermal fibroblast cell cultures, and to determine whether differences among these cell types and structures exist. Probe uptake was followed by transmission electron microscopy and fluorescence microscopy. Although the embryonic zona pellucida did not reduce uptake of the probe, the acellular capsule fully inhibited probe internalisation. Nanogold particles were taken up by endocytosis by all cell types examined in a similar manner with regard to time and intracellular migration. They were processed in endosomal compartments and accumulated within lysosomal structures after longer incubation times. In conclusion, the SmartFlare probe is applicable in equine conceptuses, but its use is limited to the developmental stages before the formation of the embryonic capsule.

The pigmentary system of developing axolotls

Development ◽  
1986 ◽  
Vol 92 (1) ◽  
pp. 255-268
Author(s):  
S. K. Frost ◽  
L. G. Epp ◽  
S. J. Robinson
Keyword(s):  
Developmental Stages ◽  
Structural Characteristics ◽  
Cell Types ◽  
Ambystoma Mexicanum ◽  
Pigment Cells ◽  
Wild Type ◽  
Transmission Electron ◽  
In The Wild ◽  
Yellow Pigments ◽  
First Time

The albino mutant in the Mexican axolotl (Ambystoma mexicanum) is analysed with respect to the differentiation of pigment cells. Pigment cells were observed with the transmission electron microscope in order to determine any unusual structural characteristics and to determine what happens to each of the cell types as development proceeds. Chemical analyses of pteridine pigments were also carried out, and the pattern of pteridines in albino animals was found to be more complex than, and quantitatively enhanced (at all developmental stages examined) over, the pattern observed in comparable wild-type axolotls. The golden colour of albino axolotls is due primarily to sepiapterin (a yellow pteridine) and secondarily to riboflavin (and other flavins). Coincident with enhanced levels of yellow pigments, xanthophore pigment organelles (pterinosomes) in albino skin reach a mature state earlier than they do in wild-type axolotl skin. This morphology is conserved throughout development in albino animals whereas it is gradually lost in the wild type. Unpigmented melanophores from albino axolotls are illustrated for the first time, and in larval albino axolotls the morphology of these cells is shown to be very similar to xanthophore morphology. In older albino animals xanthophores are easily distinguished from unpigmented melanophores. Iridophores seem to appear in albino skin at an earlier stage than they have been observed in wild-type skin. Morphologically, wild-type and albino iridophores are identical.

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