References of "Renal Physiology"
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See detailLocalization by immunofluorescent microscopy of several collagen types and of a basement membrane proteoglycan in rat glomerular epithelial and mesangial cell cultures.
Foidart, J. B.; Foidart, Jean-Michel ULg; Hassell, J. et al

in Renal Physiology (1983), 6(4), 163-70

Confluent cultures of rat glomerular epithelial and mesangial cells were studied by immunofluorescent microscopy, using affinity-purified antibodies directed against collagen of type I-V or an antiserum ... [more ▼]

Confluent cultures of rat glomerular epithelial and mesangial cells were studied by immunofluorescent microscopy, using affinity-purified antibodies directed against collagen of type I-V or an antiserum directed against a basement membrane (BM) proteoglycan. The epithelial cells were stained by antibodies directed against type I, IV and V collagen, whereas the mesangial cells were stained by all the antibodies directed against the different collagenous antigens tested. Therefore, only mesangial cells contained antigenic determinants of type III collagen. On the contrary, both cell types possessed BM proteoglycan antigens. The data suggest that rat glomerular epithelial and mesangial cells may be implicated in the biosynthesis of different components of normal (and pathological) glomerular BM. [less ▲]

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See detailSynthesis of collagen and fibronectin by glomerular cells in culture
Foidart, Jean-Michel ULg; Foidart, J. B.; Mahieu, P. R.

in Renal Physiology (1980), 3(1-6), 183-92

The biosynthesis of collagen and fibronectin molecules by cultivated glomerular epithelial or mesangial cells was studied at confluency using radioactive proline or lysine as precursors. Collagen ... [more ▼]

The biosynthesis of collagen and fibronectin molecules by cultivated glomerular epithelial or mesangial cells was studied at confluency using radioactive proline or lysine as precursors. Collagen represented 0.5% of the total protein synthesized by the glomerular epithelial cells. About 60% of this collagenous protein were associated to the cell layer, whereas about 40% were secreted into the culture medium. Two major collagenous polypeptides were observed with apparent molecular weights of 185K and 170K, and were identified as two gene products of type IV procollagen. They exhibited ratios of 3- to 4-hydroxyproline, of total hydroxyproline to proline, and of hydroxylysine to lysine characteristic of type IV procollagen. They were degraded by bacterial collagenase. The patterns of peptides obtained after digestion of the 185K and 170K chains of this type IV procollagen with pepsin and V8 protease were identical to those obtained after digestion of type IV procollagen chains purified from a murine tumor (EHS sarcoma). Finally. a purified antibody to type IV collagen specifically immunoprecipitated the collagenous protein produced by the glomerular epithelial cells. By contrast, the mesangial cells synthesized about 5% of collagenous protein. 90% of this collagen were secreted into the cultured medium, whereas about 10% remained associated to the cell layer. Type I, III and IV procollagens were synthesized by the mesangial cells. Fibronectin was found in the medium and cell layer of both epithelial and mesangial cells. Fibronectin molecules were identified by their resistance to bacterial collagenase, their susceptibility to pepsin digestion, and their specific adherence to collagen. It was composed of disulfide-linked peptides of 220K daltons. The data therefore demonstrate that: (a) the glomerular epithelial and mesangial cells synthesize fibronectin molecules and type IV procollagen in vitro; (b) the cultivated mesangial cells also synthesize type I and III collagens. The implications of these findings in certain pathological circumstances, such as diabetes mellitus, are now being investigated. [less ▲]

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