Fibronectin presence in native collagen fibrils of human fibroblasts: immunoperoxidase and immunoferritin localization.

in Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society (1980), 28(12), 1319-33

Fibronectin is a major constituent of the fibroblast extracellular matrix. Fibronectin binds to collagen, mediates fibroblast adhesion to collagen, and is synthesized and secreted into the medium of ... [more ▼]

Fibronectin is a major constituent of the fibroblast extracellular matrix. Fibronectin binds to collagen, mediates fibroblast adhesion to collagen, and is synthesized and secreted into the medium of cultured fibroblasts. Affinity-purified antibodies to fibronectin and collagen were localized using the peroxidase-antiperoxidase method or with ferritin-coupled secondary antibodies. Using human fibroblasts cultured under routine conditions, fibronectin and procollagen I react in a nonperiodic manner with: 1) approximately 10 nm extracellular fibrils, 2) cell membrane, and 3) membrane-associated vesicles. All fibrils react with both antibodies, suggesting some form of codistribution of fibronectin and collagen in these fibrils. Treatment with ascorbate leads to the development of a larger diameter extracellular fibril, approximately 40 nm in diameter. These large diameter fibrils are clearly collagen fibrils as documented by the procollagen antibody reaction. Importantly, fibronectin is bound to or a constituent of these "native" or cellular made collagen fibrils. Fibronectin and procollagen antibodies localized with the peroxidase-antiperoxidase method have a 70 nm axial repeat of reaction product on ascorbate-treated fibroblasts. Localization of antibodies with ferritin-labeled secondary antibodies is less satisfactory, but supports the basic observations made with the unlabeled antibody enzyme method. This observation rules out any potential criticisms. Although it is more difficult to observe with immunoferritin, there is an indication that antibodies to fibronectin react with an axial periodicity on cellular produced collagen fibrils. [less ▲]

Conditioned medium from endothelial cell cultures can restore the normal phenotypic expression of vascular endothelium maintained in vitro in the absence of fibroblast growth factor

in Journal of Cellular Physiology (1980), 103(2), 333-47

The epidermal cell which selectively adheres to a collagen substrate is the basal cell.

in Journal of Investigative Dermatology (1980), 74(1), 54-8

In order to determine whether a specific subpopulation of epidermal cells selectively attaches to collagen substrates in vitro, epidermal cell suspensions, obtained by trypsinization of guinea pig skin ... [more ▼]

In order to determine whether a specific subpopulation of epidermal cells selectively attaches to collagen substrates in vitro, epidermal cell suspensions, obtained by trypsinization of guinea pig skin, were incubated on type I or type IV collagen-coated glass cover slips. It was noted, morphologically and by electronic volume measurements, that small round cells, as opposed to the larger angulated flat cells, adhered to the collagen substrates. To further characterize the attached cells, the percentage of basal cells was determined in the attached cell population and in the initial epidermal cell suspension. Basal cells were identified by indirect immunofluorescence in 2 ways: (1) by the presence of pemphigoid antigen and (2) by the absence of upper cytoplasmic antigen, which is present in all keratinocytes except the basal cells. Whereas in the initial guinea pig epidermal cell suspensions about 50% of the cells were basal cells using either of these 2 criteria, 86-97% of the cells which adhered to the collagen substrates were basal cells. Human basal cells, as defined by pemphigoid antigen, also selectively adhered to the collagen substrates. [less ▲]

Laminin--a glycoprotein from basement membranes.

in Journal of Biological Chemistry (1979), 254(19), 9933-7

We have isolated a large noncollagenous glycoprotein, laminin, from a mouse tumor that produces basement membrane. The protein consists of at least two polypeptide chains (Mr = 220,000 and Mr = 440,000 ... [more ▼]

We have isolated a large noncollagenous glycoprotein, laminin, from a mouse tumor that produces basement membrane. The protein consists of at least two polypeptide chains (Mr = 220,000 and Mr = 440,000) joined to each other by disulfide bonds. Laminin and type IV collagen are major constituents of the tumor. Laminin is distinctly different from fibronectin, another component of basement membranes, in amino acid composition and immunological reactivity. Pepsin digestion of laminin releases a large, cystine-rich fragment which retains most of the antigenicity of the original protein. Immunological studies using purified antibody against laminin show that it is produced by a variety of cultured cells. In addition, these antibodies react with the basement membranes of normal tissues, suggesting that this protein or an immunologically related protein is a constituent of the basement membranes of these tissues. [less ▲]

Dexamethasone-induced accumulation of a fibronectin and collagen extracellular matrix in transformed human cells.

in Nature (1979), 277(5695), 393-5

Identification of micrometastasis of breast carcinomas by presence of basement membrane collagen.

in Lancet (1979), 2(8134), 146-7

Hormonal requirements for basement membrane collagen deposition by cultured rat mammary epithelium.

in Laboratory Investigation : Journal of Technical Methods & Pathology (1979), 41(6), 511-8

Alveoli and ducts isolated from virgin rat mammary glands synthesize basement membrane collagen (typeIV) in primary culture. Using purified antibodies to type IV collagen, prominent intracellular and ... [more ▼]

Alveoli and ducts isolated from virgin rat mammary glands synthesize basement membrane collagen (typeIV) in primary culture. Using purified antibodies to type IV collagen, prominent intracellular and extracellular fluorescence is observed in the epithelium. No fluorescence is observed with antibodies to collagen type I and III. From quantitation of the incorporation of [14c]proline-labeled proteins, 1.5 to 2.5 per cent of the newly synthesized proteins are collagen. Type IV collagen from these cultures was biochemically identified on the basis of (1) the high ratio of labeled 3-hydroxyproline to 4-hydroxyproline (1:10), (2) the gel electrophoretic pattern of the collagenase-sensitive proteins precipitated with 1.7 M NaCl, (3)the failure of the collagen to bind to diethylaminoethyl-cellulose, and(4)the immunologic cross-reactivity with mouse tumor type IV is identical with that of type IV collagen from other sources. When the supportive hormones, insulin, prolactin, hydrocortisone, progesterone, and estradiol are removed from the cultures, there is a 90 per cent reduction in the amount of [3H]proline recovered in collagen synthesis coincides with only a 30 percentdrop in the growht rate and a 20 per cent drop in total protein synthesis of the sells over the 24-hour period without hormones. Pulse-chase experimout hormones. Pulse-chase experiments revealed an enhanced turnover of collagen following hormone withdrawal. This system may be an in vitro model of collagen turnover in mammary gland in involution. [less ▲]

Aortic collagen biosynthesis during renal hypertension, pregnancy and hypertension during pregnancy in the rat.

in Biomedicine (1978), 28(4), 215-9

The synthesis and deposition of collagen and other proteins has been measured in the aorta of the rat by radiolabeling in short term organ culture. Under these conditions, the synthesis of collagen and ... [more ▼]

The synthesis and deposition of collagen and other proteins has been measured in the aorta of the rat by radiolabeling in short term organ culture. Under these conditions, the synthesis of collagen and other proteins is linear for at least five hours. Autoradiography demonstrates a labeling in all cell layers and protein deposition in the extracellular matrix. Hypertension was induced by renal ischemia using Goldblatt's technique. The synthesis and deposition of collagen was stimulated in aorta from the first week of hypertension and in pregnancy, and was even more increased in hypertensive pregnant animals. Reserpine suppresses the rise in blood pressure in operated animals and prevents these modifications. [less ▲]

The relationship between blood pressure and aortic collagen metabolism in renal hypertensive rats.

in Clinical Science and Molecular Medicine (1978), 4

1. Biosynthesis and deposition of collagen, as well as DNA and total proteins, are increased in aortae of rats after 1, 3 and 6 weeks of hypertension. 2. The maximal increase in the rate of synthesis of ... [more ▼]

1. Biosynthesis and deposition of collagen, as well as DNA and total proteins, are increased in aortae of rats after 1, 3 and 6 weeks of hypertension. 2. The maximal increase in the rate of synthesis of collagen is observed within one week of hypertension when the stress to the arterial wall is maximal. 3. Reserpine administration prevents hypertension and inhibits the increase of collagen metabolism. 4. At any time of evolution of the hypertension, a linear positive correlation is found between the collagen content in the aorta and the level of blood pressure. 5. These data suggest that synthesis of matrix components by the arterial smooth-muscle cells is controlled by variation in the blood pressure level and is not a direct consequence of circulating humoral factors liberated by the ischaemic kidney. [less ▲]

Mechanics of the pregnant uterus. I. Mechanics properly told

in Revue Médicale de Liège (1977), 32