scholarly journals A Critical Role for the Membrane-type 1 Matrix Metalloproteinase in Collagen Phagocytosis

2006 ◽  
Vol 17 (11) ◽  
pp. 4812-4826 ◽  
Author(s):  
Hyejin Lee ◽  
Christopher M. Overall ◽  
Christopher A. McCulloch ◽  
Jaro Sodek
Keyword(s):  
Inflammatory Diseases ◽  
Human Fibroblasts ◽  
Critical Role ◽  
Collagen Fibrils ◽  
Connective Tissues ◽  
Transmission Electron ◽  
Catalytically Active ◽  
Membrane Type ◽  
Collagen Phagocytosis ◽  
Interfering Rna

Degradation of collagen is important for the physiological remodeling of connective tissues during growth and development as well as in wound healing, inflammatory diseases, and cancer cell invasion. In remodeling adult tissues, degradation of collagen occurs primarily through a phagocytic pathway. However, although various steps in the phagocytic pathway have been characterized, the enzyme required to initially fragment collagen fibrils for subsequent phagocytosis has not been identified. We have used laser confocal microscopy, transmission electron microscopy, and biochemical assays to show that human fibroblasts initiate degradation of collagen through the collagenase activity of the membrane-bound metalloproteinase MT1-MMP. Degradation of natural and reconstituted collagen substrates correlated with the expression of MT1-MMP, which was localized at sites of collagen cleavage at the surface of the cells and also within the cells, whereas collagen degradation was abrogated when MT1-MMP expression was blocked by small interfering RNA treatment. In contrast to MT1-MMP, the gelatinolytic activity of MMP-2 was not required for collagen phagocytosis. These studies demonstrate a pivotal role of catalytically active MT1-MMP in preparing collagen fibrils for phagocytic degradation.

Phagocytosis of collagen by fibroblasts and invasive cancer cells is mediated by MT1-MMP

2007 ◽  
Vol 35 (4) ◽  
pp. 704-706 ◽  
Author(s):  
H. Lee ◽  
K.L. Sodek ◽  
Q. Hwang ◽  
T.J. Brown ◽  
M. Ringuette ◽  
...  
Keyword(s):  
Inflammatory Diseases ◽  
Collagen Fibrils ◽  
Connective Tissues ◽  
Cancer Breast ◽  
Metastatic Cells ◽  
Transmission Electron ◽  
Biochemical Assays ◽  
Catalytically Active ◽  
Membrane Type ◽  
Collagen Phagocytosis

Degradation of collagen is required for the physiological remodelling of connective tissues during growth and development, as well as in wound healing, inflammatory diseases, and cancer cell invasion. In remodelling adult tissues, degradation of collagen occurs primarily through a phagocytic pathway. While various steps in this pathway have been characterized, the enzyme required to fragment collagen fibrils for phagocytosis has not been identified. Laser confocal microscopy, transmission electron microscopy and biochemical assays were used to show that degradation of collagen substrates by fibroblasts correlated with the expression of the membrane-bound metalloproteinase MT1-MMP (membrane-type 1 matrix metalloproteinase). The MT1-MMP was localized to sites of collagen cleavage on the cell surface and also within the cells. In contrast with MT1-MMP, the gelatinase MMP-2 was not required for collagen phagocytosis. Similar analyses of several ovarian cancer, breast cancer and fibrosarcoma cells indicated that highly metastatic cells also degrade collagen through a phagocytic pathway that is mediated by MT1-MMP. Collectively, these studies demonstrate a pivotal role for catalytically active MT1-MMP in preparing collagen fibrils for phagocytic degradation by normal and transformed cells.

scholarly journals Lumican Regulates Collagen Fibril Assembly: Skin Fragility and Corneal Opacity in the Absence of Lumican

1998 ◽  
Vol 141 (5) ◽  
pp. 1277-1286 ◽  
Author(s):  
Shukti Chakravarti ◽  
Terry Magnuson ◽  
Jonathan H. Lass ◽  
Karl J. Jepsen ◽  
Christian LaMantia ◽  
...  
Keyword(s):  
Collagen Fibril ◽  
Significant Proportion ◽  
Keratan Sulfate ◽  
Corneal Opacity ◽  
Collagen Fibrils ◽  
Mutant Mice ◽  
Connective Tissues ◽  
Ehlers Danlos Syndrome ◽  
Transmission Electron ◽  
Skin Fragility

Lumican, a prototypic leucine-rich proteoglycan with keratan sulfate side chains, is a major component of the cornea, dermal, and muscle connective tissues. Mice homozygous for a null mutation in lumican display skin laxity and fragility resembling certain types of Ehlers-Danlos syndrome. In addition, the mutant mice develop bilateral corneal opacification. The underlying connective tissue defect in the homozygous mutants is deregulated growth of collagen fibrils with a significant proportion of abnormally thick collagen fibrils in the skin and cornea as indicated by transmission electron microscopy. A highly organized and regularly spaced collagen fibril matrix typical of the normal cornea is also missing in these mutant mice. This study establishes a crucial role for lumican in the regulation of collagen assembly into fibrils in various connective tissues. Most importantly, these results provide a definitive link between a necessity for lumican in the development of a highly organized collagenous matrix and corneal transparency.

Fibroblast adhesion on collagen substrata in the presence and absence of plasma fibronectin

1981 ◽  
Vol 48 (1) ◽  
pp. 19-34
Author(s):  
F. Grinnell ◽  
M.H. Bennett
Keyword(s):  
Electron Microscopy ◽  
Human Fibroblasts ◽  
Cell Spreading ◽  
Collagen Fibrils ◽  
Early Passage ◽  
Tissue Organization ◽  
Collagen Lattice ◽  
Transmission Electron ◽  
Initial Adhesion ◽  
Fibroblast Adhesion

We have used scanning electron microscopy and transmission electron microscopy to compare the initial adhesion of baby hamster kidney (BHK) cells and early passage human skin fibroblasts on glass, dried collagen, and hydrated collagen substrata. On glass or dried collagen substrata, BHK cell spreading required fibronectin and the cells were extensively flattened, with broad lamellipodia. In marked contrast, BHK cell spreading on hydrated collagen substrata did not require fibronectin and the cell bodies tended to be rounded, with one or several large filipodia. These filipodia generally penetrated into collagen lattice where they interwove with the collagen fibrils. Proteolysis of the collagen was not evident. In the presence of fibronectin, the morphology of BHK cell spreading on hydrated collagen substrata was similar, except that there was an increase in the number of cells that spread with lamellipodia that did not penetrate the collagen lattice. Human fibroblasts also demonstrated marked differences in cell spreading on glass or dried collagen compared to hydrated collagen substrata. Spreading was characterized by lamellipodia on glass or dried collagen but by multiple filipodia on hydrated collagen. In the latter case, the filipodia penetrated just beneath the surface of the collagen lattice. Added fibronectin was not required for spreading on human fibroblasts on any of the substrata and the presence of added fibronectin had no effect on cell morphology. Finally, the human fibroblasts were observed to form adhesion plaques in some cases where the fibroblasts made close contacts with individual collagen fibrils. The results are discussed in terms of connective tissue organization.

Banded Structures in the Connective Tissue of Meningioma

1976 ◽  
Vol 34 ◽  
pp. 234-235
Author(s):  
C. N. Sun ◽  
H. J. White
Keyword(s):  
Connective Tissue ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Collagen Fibrils ◽  
Lead Citrate ◽  
Connective Tissues ◽  
Native Collagen ◽  
Routine Procedures

Previously, we have reported on extracellular cross-striated banded structures in human connective tissues of a variety of organs (1). Since then, more material has been examined and other techniques applied. Recently, we studied a fibrocytic meningioma of the falx. After the specimen was fixed in 4% buffered glutaraldehyde and post-fixed in 1% buffered osmium tetroxide, other routine procedures were followed for embedding in Epon 812. Sections were stained with uranyl acetate and lead citrate. There were numerous cross striated banded structures in aggregated bundle forms found in the connecfive tissue of the tumor. The banded material has a periodicity of about 450 Å and where it assumes a filamentous arrangement, appears to be about 800 Å in diameter. In comparison with the vicinal native collagen fibrils, the banded material Is sometimes about twice the diameter of native collagen.

Salivary mir-27b Expression in Oral Lichen Planus Patients: A Series of Cases and a Narrative Review of Literature

2020 ◽  
Vol 19 (31) ◽  
pp. 2816-2823 ◽  
Author(s):  
Dario Di Stasio ◽  
Laura Mosca ◽  
Alberta Lucchese ◽  
Donatella Delle Cave ◽  
Hiromichi Kawasaki ◽  
...  
Keyword(s):  
Lichen Planus ◽  
Oral Lichen Planus ◽  
Inflammatory Diseases ◽  
Biological Fluids ◽  
Critical Role ◽  
Invasive Procedure ◽  
Control Group ◽  
Study Group ◽  
Immune Functions ◽  
Oral Lichen

Background: microRNAs play a critical role in auto-immunity, cell proliferation, differentiation and cell death. miRNAs are present in all biological fluids, and their expression is essential in maintaining regular immune functions and preventing autoimmunity, whereas miRNA dysregulation may be associated with the pathogenesis of autoimmune and inflammatory diseases. Oral lichen planus (OLP) is an inflammatory disease mediated by cytotoxic T cells attack against epithelial cells. The present study aims to perform a specific microRNA expression profile through the analysis of saliva in this disease. Methods: The study group was formed by five patients (mean age 62.8±1.98 years; 3 females/2 males) affected by oral lichen planus and control group by five healthy subjects (mean age 59.8 years±2.3; 3 females/ 2 males); using a low-density microarray analysis, we recorded a total of 98 differentially expressed miRNAs in the saliva of patients with oral lichen planus compared to the control group. The validation was performed for miR-27b with qRT-PCR in all saliva samples of oral lichen planus group. Results: 89 miRNAs were up-regulated and nine down-regulated. In details, levels of miR-21, miR- 125b, miR-203 and miR15b were increased (p<0.001) in study group while levels of miR-27b were about 3.0-fold decreased compared to controls (p<0.001) of miR-27b expression in OLP saliva. QRTPCR validation confirmed the down regulation of miR-27b in all saliva samples. Conclusions: Collecting saliva samples is a non-invasive procedure and is well accepted by all patients. microRNAs can be readily isolated and identified and can represent useful biomarkers of OLP.

scholarly journals Expression and function of Smad7 in autoimmune and inflammatory diseases

2021 ◽  
Author(s):  
Yiping Hu ◽  
Juan He ◽  
Lianhua He ◽  
Bihua Xu ◽  
Qingwen Wang
Keyword(s):  
Posttranscriptional Regulation ◽  
Molecular Mechanisms ◽  
Transforming Growth Factor ◽  
Inflammatory Diseases ◽  
Kidney Diseases ◽  
Critical Role ◽  
Transforming Growth Factor Β ◽  
Negative Regulator ◽  
Signaling Mechanism ◽  
And Function

AbstractTransforming growth factor-β (TGF-β) plays a critical role in the pathological processes of various diseases. However, the signaling mechanism of TGF-β in the pathological response remains largely unclear. In this review, we discuss advances in research of Smad7, a member of the I-Smads family and a negative regulator of TGF-β signaling, and mainly review the expression and its function in diseases. Smad7 inhibits the activation of the NF-κB and TGF-β signaling pathways and plays a pivotal role in the prevention and treatment of various diseases. Specifically, Smad7 can not only attenuate growth inhibition, fibrosis, apoptosis, inflammation, and inflammatory T cell differentiation, but also promotes epithelial cells migration or disease development. In this review, we aim to summarize the various biological functions of Smad7 in autoimmune diseases, inflammatory diseases, cancers, and kidney diseases, focusing on the molecular mechanisms of the transcriptional and posttranscriptional regulation of Smad7.

Growth and development of collagen fibrils in immature tissues from rat and sheep

1981 ◽  
Vol 212 (1186) ◽  
pp. 85-92 ◽  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Collagen Fibril ◽  
Growth And Development ◽  
Collagen Fibrils ◽  
Diameter Distribution ◽  
Rat Tissues ◽  
Transmission Electron ◽  
The Mean ◽  
Fibril Diameter

The collagen fibril diameter distribution of four immature tissues from both rat and sheep have been determined from transverse sections observed in the transmission electron microscope. In many instances before birth, the form of the distribution for the tissues is both unimodal and sharp and the mean diameters of the distributions lie close to a multiple of 80 Å. For some tissues, the collagen fibril diameter distributions may be resolved into a number of components, each of which represents a population of fibrils with a diameter close to a multiple of 80 Å (8 nm). These data confirm and extend previous observations by the authors that small collagen fibrils all have diameters that are multiples of about 80 Å and that the fibril growth occurs by the accretion of 80 Å units. The form of the collagen fibril diameter distribution at birth is broad for the sheep tissues but narrow for the rat tissues, thus confirming that the range of fibril diameters at this stage of life reflects the differing degree of development of precocious and altricious animals.

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.

Collagen Phagocytosis by Fibroblasts in the Periodontal Ligament of the Mouse Molar During the Initial Phase of Hypofunction

1987 ◽  
Vol 66 (12) ◽  
pp. 1708-1712 ◽  
Author(s):  
W. Beertsen
Keyword(s):  
Electron Microscopy ◽  
Morphometric Analysis ◽  
Extracellular Space ◽  
Periodontal Ligament ◽  
Initial Phase ◽  
Volume Density ◽  
Collagen Fibrils ◽  
Fibrillar Collagen ◽  
Collagen Phagocytosis

This study was undertaken in order to determine whether hypofunction of teeth is associated with changes in collagen phagocytosis by fibroblasts of the periodontal ligament. In mice, the lower right molars were extracted and the animals killed one, two, three, four, or seven days later. The maxillary first molars with their surrounding periodontium were processed for electron microscopy and their periodontal ligament subjected to morphometric analysis. It was observed that, whereas the volume density of extracellular collagen in the ligament of the hypofunctional molars decreased from 50% to 30% during the course of the experiment the fraction of fibrillar collagen ingested by the cells increased over two-fold. This increase was already manifest very shortly after the onset of the experiment and offers an explanation for the net loss of collagen fibrils from the extracellular space.

scholarly journals Genetically modified human type II collagen for N- and C-terminal covalent tagging

2018 ◽  
Vol 96 (2) ◽  
pp. 204-211
Author(s):  
Andrew Wieczorek ◽  
Clara K. Chan ◽  
Suzana Kovacic ◽  
Cindy Li ◽  
Thomas Dierks ◽  
...  
Keyword(s):  
Developmental Disorders ◽  
Connective Tissue Diseases ◽  
Sulfhydryl Group ◽  
Type Ii Collagen ◽  
Type Ii ◽  
Structural Protein ◽  
Connective Tissues ◽  
Human Type ◽  
C Terminus ◽  
Transmission Electron

Collagen is the predominant structural protein in vertebrates, where it contributes to connective tissues and the ECM; it is also widely used in biomaterials and tissue engineering. Dysfunction of this protein and its processing can lead to a wide variety of developmental disorders and connective tissue diseases. Recombinantly engineering the protein is challenging due to post-translational modifications generally required for its stability and secretion from cells. Introducing end labels into the protein is problematic, because the N- and C-termini of the physiologically relevant tropocollagen lie internal to the initially flanking N- and C-propeptide sequences. Here, we introduce mutations into human type II procollagen in a manner that addresses these concerns and purify the recombinant protein from a stably transfected HT1080 human fibrosarcoma cell line. Our approach introduces chemically addressable groups into the N- and C-telopeptide termini of tropocollagen. Simultaneous overexpression of formylglycine generating enzyme (FGE) allows the endogenous production of an aldehyde tag in a defined, substituted sequence in the N terminus of the mutated collagen, whereas the C-terminus of each chain presents a sulfhydryl group from an introduced cysteine. These modifications are designed to enable specific covalent end-labelling of collagen. We find that the doubly mutated protein folds and is secreted from cells. Higher order assembly into well-ordered collagen fibrils is demonstrated through transmission electron microscopy. Chemical tagging of thiols is successful; however, background from endogenous aldehydes present in wild-type collagen has thus far obscured the desired specific N-terminal labelling. Strategies to overcome this challenge are proposed.

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