scholarly journals Immunohistochemical evidence for the intracellular formation of basement membrane collagen (type IV) in developing tissues.

1980 ◽  
Vol 28 (12) ◽  
pp. 1267-1274 ◽  
Author(s):  
G W Laurie ◽  
C P Leblond ◽  
I Cournil ◽  
G R Martin
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Early Stage ◽  
Basement Membranes ◽  
Incisor Tooth ◽  
Rat Incisor ◽  
Type Iv ◽  
Stage Of Development ◽  
Basement Membrane Collagen ◽  
Membrane Collagen

Antibodies to type IV collagen obtained from the basement membrane of the mouse EHS tumor were incubated with sections of rat incisor teeth and other tissues for immunostaining by direct or indirect methods. In all locations, the immunostaining was pronounced in basement membranes in which it was restricted to the "basal lamina" layer, from which "bridges" often extended to nearby basal laminae. Usually no immunostaining was detectable in the cells associated with the basement membranes. However, examination of the capillaries at the posterior extremity of the rat incisor tooth, where tissues are at an early stage of development, showed immunostaining not only of the basement membrane, but also of the endothelial cells. The staining was localized in rough endoplasmic reticulum cisternae, some Golgi saccules and their peripheral distensions, and structures believed to be secretory granules. These findings suggest that the synthesis of type IV collagen proceeds along the classical secretory pathways through rough endoplasmic reticulum and Golgi apparatus. At the same time, immunostaining was usually lacking in the cells of the capillaries that had migrated about 2 mm away from the posterior end of the incisor tooth and also in the cells of most other tissues examined, even though the associated basal laminae were reactive. It is, therefore, presumed that the production of type IV collagen may be high in cells at an early stage of development and that any later production and turnover of basement membrane collagen can only be minimal.

scholarly journals Cross-linking in type IV collagen

1984 ◽  
Vol 218 (3) ◽  
pp. 713-723 ◽  
Author(s):  
A J Bailey ◽  
T J Sims ◽  
N Light
Keyword(s):  
Basement Membrane ◽  
Type Iv Collagen ◽  
Collagen Molecule ◽  
Cross Linking ◽  
Type Iv ◽  
Long Form ◽  
Basement Membrane Collagen ◽  
Cross Links ◽  
Membrane Collagen ◽  
Salt Fractionation

Type IV collagen could not be extracted from human placenta using 6M-urea containing 10mM-dithiothreitol, indicating that the type IV molecule is stabilized within the basement membrane by covalent cross-links. However, various forms of type IV collagen molecule were extractable by means of increasingly severe proteolytic conditions. Type IV collagen tetramers (‘spiders’) lacking only the C-terminal globular region (NC1) were further digested to the ‘long-form’ 7S fragment and an assortment of helical rod-like molecules derived from the ‘leg’ region. These molecules were separated by salt fractionation and examined by rotary-shadowing electron microscopy. Isolation of these fractions from placenta which had been reduced with NaB3H4 revealed that both the 7S (N-terminal) and C-terminal regions contained significant proportions of reducible lysine-derived cross-links. These cross-links were shown to be exclusively the stable oxo-imine hydroxylysino-5-oxonorleucine. The number of the cross-links per molecule was significantly lower than might be expected in order to fully stabilize the molecule. These results suggest that the keto-imine cross-links in type IV collagen have been stabilized in part by conversion into an unknown non-reducible form, although a sensitive immunoassay failed to show the presence of any pyridinoline. Comparison with the fibrous collagen from placenta suggested that the rate of this conversion is much greater in basement-membrane collagen.

scholarly journals What is Known of the Production of Basement Membrane Components

1983 ◽  
Vol 31 (1A_suppl) ◽  
pp. 159-163 ◽  
Author(s):  
G.W. Laurie ◽  
C.P. Leblond
Keyword(s):  
Golgi Apparatus ◽  
Basement Membrane ◽  
Type Iv Collagen ◽  
Secretory Granules ◽  
Basement Membranes ◽  
Type Iv ◽  
Stage Of Development ◽  
Membrane Components ◽  
Endodermal Cells ◽  
Basement Membrane Components

Immunohistochemistry was used to identify basement membrane components and examine their production by associated cells. Four substances were identified in a series of basement membranes in rats aged 20 days to 34 months, namely, type IV collagen, laminin, heparan sulfate proteoglycan, and fibronectin. They were then all localized to the basal lamina part of basement membranes and, presumably, are integrated within this layer. The production of type IV collagen was first examined in the embryonic endodermal cells associated with Reichert's membrane in the rat parietal yolk sac. The rough endoplasmic reticulum (rER), Golgi apparatus, and putative secretory granules of endodermal cells were immunostained, suggesting that these organelles participated in the biogenesis of type IV collagen. However, in rats aged 20 days or more, the cells associated with basement membranes were usually unstained. An exception was noted in the continually growing incisor tooth where the endothelial cells at the proliferating end usually showed immunostaining of rER and Golgi apparatus. It is, therefore, proposed that the formation of type IV collagen for basement membrane occurs at an early stage of development in the life of producer cells. Little is known of the formation of other basement membrane components during development, but there is immunohistochemical evidence that laminin and fibronectin are produced along the same secretory pathway as type IV collagen.

scholarly journals Structural studies of human basement-membrane collagen with the use of a monoclonal antibody

1985 ◽  
Vol 227 (1) ◽  
pp. 217-222 ◽  
Author(s):  
H Dieringer ◽  
D W Hollister ◽  
R W Glanville ◽  
L Y Sakai ◽  
K Kühn
Keyword(s):  
Monoclonal Antibody ◽  
Basement Membrane ◽  
Type Iv Collagen ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Type Iv ◽  
Structural Probe ◽  
Basement Membrane Collagen ◽  
Antigen Antibody ◽  
Membrane Collagen

A monoclonal antibody monospecific for human type IV collagen was used as a structural probe to examine aspects of the macromolecular organization of basement-membrane collagen. Electron-microscopic observation of rotary-shadowed antigen-antibody complexes demonstrated a unique binding site for the antibody 55 +/- 6 nm distant from the 7S cross-linking region of tetrameric type IV collagen. This observation allowed a series of studies that showed: (1) the localization of an intramolecular disulphide bridge within the helical domain of the molecule, (2) the alignment of major peptic-digest fragments of the alpha 1 (IV) chain, and (3) confirmation of the postulated antiparallel arrangement of individual molecules within type IV collagen tetramers.

scholarly journals Dynamically remodeled hepatic extracellular matrix predicts prognosis of early-stage cirrhosis

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Yuexin Wu ◽  
Yuyan Cao ◽  
Keren Xu ◽  
Yue Zhu ◽  
Yuemei Qiao ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Basement Membrane ◽  
Type Iv Collagen ◽  
Patient Survival ◽  
Early Stage ◽  
Ecm Remodeling ◽  
Type Iv ◽  
Ecm Proteins ◽  
Stage Disease ◽  
Cirrhotic Patients

AbstractLiver cirrhosis remains major health problem. Despite the progress in diagnosis of asymptomatic early-stage cirrhosis, prognostic biomarkers are needed to identify cirrhotic patients at high risk developing advanced stage disease. Liver cirrhosis is the result of deregulated wound healing and is featured by aberrant extracellular matrix (ECM) remodeling. However, it is not comprehensively understood how ECM is dynamically remodeled in the progressive development of liver cirrhosis. It is yet unknown whether ECM signature is of predictive value in determining prognosis of early-stage liver cirrhosis. In this study, we systematically analyzed proteomics of decellularized hepatic matrix and identified four unique clusters of ECM proteins at tissue damage/inflammation, transitional ECM remodeling or fibrogenesis stage in carbon tetrachloride-induced liver fibrosis. In particular, basement membrane (BM) was heavily deposited at the fibrogenesis stage. BM component minor type IV collagen α5 chain expression was increased in activated hepatic stellate cells. Knockout of minor type IV collagen α5 chain ameliorated liver fibrosis by hampering hepatic stellate cell activation and promoting hepatocyte proliferation. ECM signatures were differentially enriched in the biopsies of good and poor prognosis early-stage liver cirrhosis patients. Clusters of ECM proteins responsible for homeostatic remodeling and tissue fibrogenesis, as well as basement membrane signature were significantly associated with disease progression and patient survival. In particular, a 14-gene signature consisting of basement membrane proteins is potent in predicting disease progression and patient survival. Thus, the ECM signatures are potential prognostic biomarkers to identify cirrhotic patients at high risk developing advanced stage disease.

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