scholarly journals ELECTRON MICROSCOPY OF THE HUMAN SYNOVIAL MEMBRANE

1962 ◽  
Vol 14 (2) ◽  
pp. 207-220 ◽  
Author(s):  
Peter Barland ◽  
Alex B. Novikoff ◽  
David Hamerman
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Synovial Membrane ◽  
Current Knowledge ◽  
Cell Types ◽  
Type B ◽  
Joint Cavity ◽  
The Matrix ◽  
And Function ◽  
Cytoplasmic Processes

The structure of the lining cells at the surface of the synovial membrane facing the joint cavity has been studied by electron microscopy. The long cytoplasmic processes of these cells appear to be oriented toward the surface of the membrane, where they overlap and intertwine. The matrix of the lining cells contains dense material but no fibers with the periodicity of collagen. The lining cells are divided into two cell types or states of activity on the basis of their cytoplasmic contents. Type A is more numerous and contains a prominent Golgi apparatus, numerous vacuoles (0.4 to 1.5 microns in diameter) containing varying amounts of a dense granular material, many filopodia, mitochondria, intracellular fibrils, and micropinocytotic-like vesicles. Type B contains large amounts of ergastoplasm with fewer large vacuoles, micropinocytotic-like vesicles, and mitochondria. The probable functions of these cells are discussed in the light of current knowledge of the metabolism and function of the synovial membrane.

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.

scholarly journals Mitochondrial Heterogeneity in the Brain at the Cellular Level

1998 ◽  
Vol 18 (3) ◽  
pp. 231-237 ◽  
Author(s):  
Ursula Sonnewald ◽  
Leif Hertz ◽  
Arne Schousboe
Keyword(s):  
Amino Acid ◽  
Current Knowledge ◽  
Cell Types ◽  
Cellular Level ◽  
Mitochondrial Structure ◽  
Cell Type Specific ◽  
Mitochondrial Heterogeneity ◽  
Specific Tissue ◽  
And Function ◽  
The Brain

Classically, compartmentation of glutamate metabolism in the brain is associated with the fact that neurons and glia exhibit distinct differences with regard to metabolism of this amino acid. The recent use of 13C-labeled compounds to study this metabolism in conjunction with the availability of cell type-specific tissue culture modes has led to the notion that such compartmentation may even be present in individual cell types, neurons as well as glia. To better understand and explain this, it is proposed that mitochondrial heterogeneity may exist resulting in tricarboxylic acid cycles with different properties regarding cycling rates and ratio as well as coupling to amino acid biosynthesis, primarily involving glutamate and aspartate. These hypotheses are evaluated in the light of current knowledge about mitochondrial structure and function.

scholarly journals The story of the fibrin(ogen) αC-domains: evolution of our view on their structure and interactions

2021 ◽  
Author(s):  
Leonid Medved ◽  
John W Weisel
Keyword(s):  
Binding Sites ◽  
Current Knowledge ◽  
Optical Trap ◽  
Cell Types ◽  
Ordered Structures ◽  
Multiple Binding Sites ◽  
New Information ◽  
Multiple Binding ◽  
And Function ◽  
Fibrinogen Molecule

Although much has been established concerning the overall structure and function of fibrinogen, much less has been known about its two αC regions, each consisting of an αC-connector and αC-domain, but new information has been accumulating. This review summarizes the state of our current knowledge of the structure and interactions of fibrinogen’s αC regions. A series of studies with isolated αC regions and their fragments demonstrated that the αC-domain forms compact ordered structures consisting of N- and C-terminal sub-domains including β sheets and suggested that the αC-connector has a poly(L-proline) type II structure. Functionally, the αC-domains interact intramolecularly with each other and with the central region of the molecule, first demonstrated by electron microscopy and then quantified by optical trap force spectroscopy. Upon conversion of fibrinogen into fibrin, the αC-domains switch from intra- to intermolecular interactions to form ordered αC polymers. The formation of αC polymers occurs mainly through the homophilic interaction between the N-terminal sub-domains; interaction between the C-terminal sub-domains and the αC-connectors also contributes to this process. Considerable evidence supports the idea that the αC-regions accelerate fibrin polymerization and affect the final structure of fibrin clots. The interactions between αC-regions are important for the mechanical properties of clots, increasing their stiffness and extensibility. Conversion of fibrinogen into fibrin results in exposure of multiple binding sites in its αC regions, providing interaction of fibrin with different proteins and cell types during hemostasis and wound healing. This heretofore mysterious part of the fibrinogen molecule is finally giving up its secrets.

scholarly journals Controlled Signaling—Insulin-Like Growth Factor Receptor Endocytosis and Presence at Intracellular Compartments

2021 ◽  
Vol 11 ◽  
Author(s):  
Leonie Rieger ◽  
Rosemary O’Connor
Keyword(s):  
Golgi Apparatus ◽  
Cancer Cells ◽  
Growth Factor Receptor ◽  
Cell Types ◽  
Specific Cell ◽  
Receptor Endocytosis ◽  
Intracellular Compartments ◽  
Associated Proteins ◽  
Membrane Compartments ◽  
And Function

Ligand-induced activation of the IGF-1 receptor triggers plasma-membrane-derived signal transduction but also triggers receptor endocytosis, which was previously thought to limit signaling. However, it is becoming ever more clear that IGF-1R endocytosis and trafficking to specific subcellular locations can define specific signaling responses that are important for key biological processes in normal cells and cancer cells. In different cell types, specific cell adhesion receptors and associated proteins can regulate IGF-1R endocytosis and trafficking. Once internalized, the IGF-1R may be recycled, degraded or translocated to the intracellular membrane compartments of the Golgi apparatus or the nucleus. The IGF-1R is present in the Golgi apparatus of migratory cancer cells where its signaling contributes to aggressive cancer behaviors including cell migration. The IGF-1R is also found in the nucleus of certain cancer cells where it can regulate gene expression. Nuclear IGF-1R is associated with poor clinical outcomes. IGF-1R signaling has also been shown to support mitochondrial biogenesis and function, and IGF-1R inhibition causes mitochondrial dysfunction. How IGF-1R intracellular trafficking and compartmentalized signaling is controlled is still unknown. This is an important area for further study, particularly in cancer.

scholarly journals Neonatal Fc receptor (FcRn) – not only transporter of maternal IgG

2018 ◽  
Vol 72 ◽  
pp. 701-727
Author(s):  
Joanna E. Mikulska
Keyword(s):  
Mhc Class I ◽  
Current Knowledge ◽  
Cell Types ◽  
Fc Receptor ◽  
Class I ◽  
Neonatal Fc Receptor ◽  
The Status ◽  
And Function ◽  
Different Cell Types ◽  
Maternal Igg

The neonatal Fc receptor, (FcRn) is a transmembrane, heterodimeric glycoprotein with a structure similar to MHC class I molecules. In contrast to MHC class I antigens, FcRn does not bind to peptides (antigens) but interacts with the Fc fragment of IgG and albumin. The FcRn-IgG interaction as well as the FcRn-albumin interaction occur at acidic pH (optimally at pH 5.0-6.5) but not in physiological environment. These two ligands bind to distinct binding sites on the receptor molecule and by different mechanisms. Now, it is known that the expression of FcRn is not restricted to sites involved in the transport of maternal IgG, and this receptor is not responsible only for transfer the passive immunity from mother to the offspring. But FcRn has a much broader range of expression and function, throughout life and in many different cell types and tissues of humans and animals. This review summarizes the status of our knowledge on the expression, interaction with ligands and functions of the neonatal Fc receptor. This article shows also the possibilities of utilizing a current knowledge on FcRn for therapeutic purposes.

scholarly journals FORMATION OF BONE TISSUE IN CULTURE FROM ISOLATED BONE CELLS

1974 ◽  
Vol 61 (2) ◽  
pp. 427-439 ◽  
Author(s):  
Itzhak Binderman ◽  
Dan Duksin ◽  
Arieh Harell ◽  
Ephraim Katzir (Katchalski) ◽  
Leo Sachs
Keyword(s):  
Electron Microscopy ◽  
Bone Tissue ◽  
Bone Cells ◽  
Light And Electron Microscopy ◽  
Bone Collagen ◽  
The Matrix ◽  
Three Stages ◽  
And Function

A system is described for the formation of bone tissue in culture from isolated rat bone cells. The isolated bone cells were obtained from embryonic rat calvarium and periosteum or from traumatized, lifted periosteum of young rats. The cells were cultured for a period of up to 8 wk, during which time the morphological, biochemical, and functional properties of the cultures were studied. Formation of bone tissue by these isolated bone cells was shown, in that the cells demonstrated osteoblastic morphology in light and electron microscopy, the collagen formed was similar to bone collagen, there was mineralization specific for bone, and the cells reacted to the hormone calcitonin by increased calcium ion uptake. Calcification of the fine structure of the cells and the matrix is described. Three stages in the calcification process were observed by electron microscopy. It is concluded that these bone cells growing in vitro are able to function in a way similar to such cells in vivo. This tissue culture system starting from isolated bone cells is therefore suitable for studies on the structure and function of bone.

Composition and function of PDZ protein complexes during cell polarization

2003 ◽  
Vol 285 (3) ◽  
pp. F377-F387 ◽  
Author(s):  
Michael H. Roh ◽  
Ben Margolis
Keyword(s):  
Epithelial Cells ◽  
Current Knowledge ◽  
Protein Complexes ◽  
Cell Types ◽  
Cell Polarization ◽  
Differential Distribution ◽  
Pdz Proteins ◽  
Homologous Protein ◽  
Pdz Protein ◽  
And Function

Complexes consisting of PDZ proteins have been implicated in a variety of cellular processes. In recent years, it has become increasingly clear that PDZ proteins play essential roles during the establishment of spatial asymmetry in various metazoan cell types such as epithelial cells. Epithelial cells possess asymmetry with respect to the apicobasal axis reflected by the differential distribution of proteins and lipids in the apical and basolateral surfaces. In Drosophila, three PDZ protein complexes have been shown to play crucial functions during the establishment of cell-cell adhesions and epithelial cell polarity: Bazooka/Dm-Par6/DaPKC, Crumbs/Stardust/Discs Lost, and Scribble/Discs Large/Lethal Giant Larvae. In this review, we focus primarily on our current knowledge of the localization and function of these complexes in Drosophila epithelia. We also discuss recent data that enhance our understanding of the homologous protein complexes and their roles during junctional assembly and polarization of mammalian epithelial cells.

scholarly journals Analysis by Light, Scanning, and Transmission Microscopy of the Intima Synovial of the Temporomandibular Joint of Human Fetuses during the Development

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Carlos Sabu Alvez ◽  
Luis Otavio Carvalho de Moraes ◽  
Sergio R. Marques ◽  
Roberto C. Tedesco ◽  
Leandro J. C. Harb ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Temporomandibular Joint ◽  
Cell Types ◽  
Human Fetuses ◽  
Transmission Microscopy ◽  
Joint Cavity ◽  
Transmission Electron ◽  
Intima Layer

Objective. To characterize morphologically and ultrastructurally using light microscopy, the scanning electron microscopy and transmission electron microscopy the intima synovial of the temporomandibular joint (TMJ) of human fetuses between the 10th and the 38th week of development. Materials and Methods. The TMJ was dissected bilaterally in 37 human fetuses belonging to the Institute of Embryology of the University Complutense of Madrid and of the Federal University of São Paulo. Results. The outcome by light microscopy showed the morphology of the TMJ and that the formation of inferior joint cavity precedes the superior joint cavity and the presence of blood vessels in the synovial. Conclusion. By scanning and transmission electron microscopy we observed the presence of two well-defined cell types in the intima layer of synovial of the TMJ of human fetuses, macrophage-like type A cell and fibroblast-like type B cell, and the presence of the a third cell type, defined by the name of intermediate lining cell in the intima layer of the synovial.

scholarly journals Regenerative properties of human extraembryonal organs in tissue engineering

2018 ◽  
Vol 20 (4) ◽  
pp. 192-198
Author(s):  
L I Kalyuzhnaya ◽  
O N Kharkevich ◽  
A A Schmidt ◽  
O V Protasov
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Umbilical Cord ◽  
Current Knowledge ◽  
Biological Properties ◽  
Engineering Structures ◽  
The Matrix ◽  
Cell Growth And Differentiation ◽  
And Function ◽  
Cell Matrix Interactions

The characteristics of the umbilical cord extracellular matrix are discussed relatively of their potential use for tissue engineering. The purpose of this review is to assess the current knowledge about using of homologous biomaterials with regenerative properties to create bioengineered structures. One of the most important components of tissue engineering - matrix (scaffold), resident cells can migrate, attach to it and function. Due to their structure, matrices should be easily integrated into the patient’s tissue and provide conditions for cell growth and differentiation. The cells that populate the matrix in the bioreactor before the transplantation of this construction, or resident cells recruited into the transplanted extracellular matrix), and cell- matrix interactions are absolutely necessary components of tissue engineering. Available commercial bioengineering products made from mammalian tissues have certain advantages and significant disadvantages due to the risks of immunological reactions and transmission of infectious agents. The transplantation of products from xenogenic materials is prohibited by law in the Russian Federation. The donor material is limited, receipt of human cadaver material requires a long period of legal registration, which has a detrimental effect on the biomaterial. Therefore, finding a suitable homologous biomaterial is ongoing. Due to the peculiarities of the embryonic phenotype, extraembryonic tissues have special biological properties, one of which is the scarless healing of wounds. Low immunogenicity, optimal mechanical properties of extracellular matrix, presence of cell adhesion molecules and growth factors promoting regeneration provide anti-inflammatory, anti-fibrotic, anti- scarring properties for tissue engineering structures from umbilical cord and amniotic membrane. Umbilical cord and amnion due to the availability and non-invasiveness of obtaining from healthy young donors are an excellent source of homologous biomaterial for extracting matrices, cells and hydrogels for tissue engineering and regenerative medicine.

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