scholarly journals Effect of glycated proteins on the matrix of glomerular epithelial cells.

1998 ◽  
Vol 9 (5) ◽  
pp. 802-810
Author(s):  
A K Singh ◽  
W Mo ◽  
G Dunea ◽  
J A Arruda
Keyword(s):  
Diabetic Nephropathy ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Thymidine Uptake ◽  
Collagenase Activity ◽  
Glycated Proteins ◽  
Glomerular Epithelial Cells ◽  
Membrane Antigens ◽  
The Media ◽  
Desmosomal Protein

In this study, cultured glomerular epithelial cells (GEC) were exposed to a diabetic milieu containing glycated proteins to determine whether such proteins cause metabolic alterations that may lead to defects seen in the extracellular matrix in diabetic nephropathy. Cultured glomerular epithelial cells were cloned and maintained in RPMI media containing 10% fetal bovine serum (FBS). The medium was changed to RPMI-1% glycated FBS (experimental) or RPMI-1% control FBS, and cells were incubated for 1 or 4 d. Mitogenicity was tested by 3H-thymidine uptake. The media were collected and analyzed for collagenase activity by a quantitative fluorescence assay and by zymography. The cell layers were processed for matrix antigen (collagen I, glomerular basement membrane antigens, laminin, and fibronectin) and for the proteins of the tight junction (cadherin, desmosomal protein) by quantitative immunoperoxidase and immunofluorescence. Cell lysates were tested for cadherin and desmosomal protein by immunoblotting. Cells were also grown on 0.2-microM filter membranes to test for permeability to 3H-inulin and 125I-albumin. Glycated FBS resulted in a 1.8-fold increase in 3H-thymidine uptake in subconfluent layers accompanied by an increase in cell number. The treatment caused accumulation of laminin (18% above control, P < 0.05) and basement membrane antigens (33% above control, P < 0.05). Collagen I and fibronectin were unchanged. Exposing cells to glycated FBS changed the distribution of cadherin from a linear to a diffuse pattern associated with a decrease in cadherin observed on immunoblots. The media of glycated FBS-treated cells contained 45% lower collagenase activity (72-, 92-, and 150-kD species). Permeability to inulin increased by 550% and to albumin by 320% in glycated FBS-treated monolayers compared with controls. It is concluded that glycated proteins increased the accumulation of matrix proteins in the GEC, associated with a concomitant depression in collagenase activity. There were qualitative and quantitative changes in the tight junction protein cadherin. These matrix changes resulted in a functional defect in the permselective properties of the GEC tight junctions and manifested as increased leakage of inulin and albumin. Thus, the GEC are metabolically sensitive to the presence of glycated proteins, and this could play a role in the pathogenesis of diabetic nephropathy.

Potential autocrine and paracrine mechanisms of recovery from mechanical injury of renal tubular epithelial cells

1998 ◽  
Vol 274 (3) ◽  
pp. F463-F472 ◽  
Author(s):  
Robert J. Anderson ◽  
Carla J. Ray
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Mechanical Injury ◽  
Renal Tubular Cell ◽  
Thymidine Uptake ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
The Media ◽  
Renal Tubular

The present studies were done to clarify potential pathways of the nephrogenic repair process. Media removed from mechanically injured vascular smooth muscle cells and LLC-PK1 renal tubular epithelial cells significantly stimulated[Formula: see text]thymidine uptake and cell number in quiescent LLC-PK1 cells, demonstrating the existence of potential autocrine and paracrine pathways of nephrogenic repair. The effect of mechanical injury resulting in release of one or more growth factors into culture media was also found in the opossum kidney OK renal tubular cell line. The nonspecific peptide growth factor antagonist suramin inhibited the effect of media from injured LLC-PK1 cells to stimulate[Formula: see text]thymidine uptake in quiescent LLC-PK1 cells. Exposure of quiescent LLC-PK1 cells to six growth factors, including acidic and basic fibroblastic growth factors (aFGF and bFGF), platelet-derived growth factors AA and BB (PDGF-AA and PDGF-BB), endothelin-2, and hepatocyte growth factor, reproduced the biological responses seen when quiescent LLC-PK1 cells were exposed to media from injured cells. Immunoblotting and enzyme-linked immunosorbent assay experiments demonstrated the presence of aFGF, bFGF, and PDGF-BB but not other candidate growth factors in the media from injured LLC-PK1 cells. A neutralizing antibody directed against bFGF attenuated the effect of media from injured cells to stimulate[Formula: see text]thymidine uptake in serum-starved LLC-PK1 cells. These results demonstrate that mechanical injury to renal tubular epithelial cells results in release of aFGF, bFGF, and PDGF-BB into the media and suggests that bFGF may be involved in an autocrine fashion to promote recovery from injury.

Temporary effects of circulating Amadori products on glomerular filtration properties in the normal mouse

2001 ◽  
Vol 280 (1) ◽  
pp. F103-F111 ◽  
Author(s):  
I. Londoño ◽  
M. Bendayan
Keyword(s):  
Diabetic Nephropathy ◽  
Basement Membrane ◽  
Glomerular Filtration ◽  
Glomerular Basement Membrane ◽  
Normal Mouse ◽  
Early Diabetes ◽  
Amadori Products ◽  
Time Points ◽  
Glycated Proteins ◽  
Filtration Properties

Previous studies have established a preferential glomerular filtration of glycated BSA (gBSA), as well as a facilitated filtration of BSA in the presence of gBSA. We intend to determine whether these modifications are permanent or transitory. gBSA was intravenously injected into anesthetized normal mice and maintained in circulation for 30 min, 1, 2, 24, and 48 h. Five minutes before death, FITC-BSA was injected. On immunocytochemical evaluations, increased glomerular filtration of FITC-BSA was found at all circulating time points. Changes at 24 and 48 h were less pronounced. Glomerular basement membrane (GBM)-to-lumen gBSA labeling ratios were similar at all time points suggesting no accumulation of gBSA in the GBM. Seventy percent of the gBSA was cleared from the circulation and the GBM after 24 h, and 95% after 48 h. This was confirmed in experiments with radiolabeled tracers. These results suggest that the alteration in GBM permeability to BSA in the normal mouse are due to the presence of gBSA and are gradually overcome along with its clearance from circulation. In early diabetes, increasing concentrations of circulating glycated proteins could be responsible for changes in glomerular permselectivity and probably for the alteration in glomerular filtration properties leading to diabetic nephropathy.

SM22α: The Novel Phenotype Marker of Injured Glomerular Epithelial Cells in Anti-Glomerular Basement Membrane Nephritis

2007 ◽  
Vol 106 (3) ◽  
pp. e77-e87 ◽  
Author(s):  
Asa Ogawa ◽  
Minoru Sakatsume ◽  
Xingzhi Wang ◽  
Yunichi Sakamaki ◽  
Yutaka Tsubata ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
The Novel ◽  
Glomerular Epithelial Cells

scholarly journals Puromycin Aminonucleoside Suppresses Integrin Expression in Cultured Glomerular Epithelial Cells

2001 ◽  
Vol 12 (4) ◽  
pp. 758-766 ◽  
Author(s):  
UMA KRISHNAMURTI ◽  
BING ZHOU ◽  
WEI-WEI FAN ◽  
EFFIE TSILIBARY ◽  
ELIZABETH WAYNER ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Type Iv Collagen ◽  
Cell Detachment ◽  
Puromycin Aminonucleoside ◽  
Glomerular Epithelial Cell ◽  
Type Iv ◽  
Glomerular Epithelial Cells

Abstract. Puromycin aminonucleoside (PAN)-induced nephrosis is a well-described model of human idiopathic nephrotic syndrome, but the mechanism of PAN's effect is not completely understood. Because PAN injection into rats results in retraction of glomerular epithelial cell foot processes and glomerular epithelial cell detachment, it was hypothesized that PAN might alter the contacts between these cells and the glomerular basement membrane. The major integrin expressed by glomerular epithelial cells is α3β1, which mediates attachment of these cells to extracellular matrix proteins including type IV collagen. T-SV 40 immortalized human glomerular epithelial cells were used to study PAN's effects on α3β1 expression, as well as that of podocalyxin and the slit diaphragm component ZO-1. Glomerular epithelial cells were seeded into plastic flasks and allowed to attach and proliferate for 48 h. The cells were then incubated for another 48 h in media containing 0, 0.5, or 5.0 μg/ml PAN. PAN exposure resulted in dose-dependent decreases in α3 and β1 expression, both at the protein level and at the mRNA level. This was accompanied by a significant decrease in the adhesion of glomerular epithelial cells to type IV collagen. PAN did not affect ZO-1 protein expression. Treatment with PAN increased the expression of podocalyxin at the protein and mRNA levels. Reduced glomerular epithelial cell expression of α3β1 integrins and impaired adhesion to type IV collagen may contribute to the glomerular epithelial cell detachment from glomerular basement membrane seen in the PAN nephrosis model.

scholarly journals Glomerular epithelial cells secrete a glomerular basement membrane-degrading metalloproteinase.

1992 ◽  
Vol 2 (9) ◽  
pp. 1388-1397
Author(s):  
R Johnson ◽  
H Yamabe ◽  
Y P Chen ◽  
C Campbell ◽  
K Gordon ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Type Iv Collagen ◽  
Dependent Manner ◽  
Type Iv Collagenase ◽  
Glomerular Diseases ◽  
Major Band ◽  
Type Iv ◽  
Glomerular Epithelial Cells

Cultured rat glomerular epithelial cells (GEC) were examined for their ability to release extracellular matrix-degrading proteinases with [3H]gelatin as substrate. GEC-conditioned media, under serum-free conditions, contained modest amounts of gelatinase activity (1 to 10 U/mg of protein); the activity was maximal at neutral pH, was inhibited by zinc chelators, was not inhibited by tissue inhibitor of metalloproteinase-2, and could not be further activated by trypsin or organomercurials. Gelatin substrate sodium dodecyl sulfate-polyacrylamide gels of GEC-conditioned medium revealed several zones of lysis, with molecular sizes of 150 kd (major band), and 220, 86 to 93, and 52 to 54 kd (minor bands). Northern blot analysis demonstrated that the GEC metalloproteinase(s) were distinct from the 68- to 72-kd type IV collagenase/gelatinase present in mesangial cells or the 92-kd type IV collagenase present in neutrophils. The GEC gelatinolytic activity also degraded insoluble type IV collagen in glomerular basement membrane in a dose-dependent manner. The major metalloproteinase activity responsible for the type IV collagen degradation has a molecular size of 150 kd with a type IV collagen substrate gel. Thus, GEC produce several neutral metalloproteinases, which, by virtue of their substrate specificity, may play an important role in glomerular basement membrane remodeling and in glomerular diseases characterized by alterations in basement membrane permeability.

Leukotriene D4-induced proliferation of glomerular epithelial cells: PKC- and Na+-H+ exchanger-mediated response

1989 ◽  
Vol 257 (2) ◽  
pp. C232-C239 ◽  
Author(s):  
L. Baud ◽  
J. Perez ◽  
G. Cherqui ◽  
E. J. Cragoe ◽  
R. Ardaillou
Keyword(s):  
Epithelial Cells ◽  
Growth Effect ◽  
Thymidine Uptake ◽  
Promoting Effect ◽  
Leukotriene D4 ◽  
Glomerular Epithelial Cells ◽  
Ic50 Values ◽  
Growth Promoting ◽  
Pkc Activation

The growth-promoting effect of leukotriene D4 (LTD4) has been observed in a variety of cells, including human glomerular epithelial cells. The purpose of this study was to determine the mechanisms underlying this process. LTD4 induction of [3H]thymidine uptake in human glomerular epithelial cells was blocked by the LTD4 receptor antagonist L648,051 when added in a 50-fold excess and by pertussis toxin. Neither drug affected basal DNA synthesis. These results suggest that the LTD4-mediated signal transduction implies activation of a GTP-binding protein that is coupled to a specific receptor. The possible role of protein kinase C (PKC) activation was also studied. In the presence of the PKC inhibitor H-7 or after downregulation of PKC levels by chronic treatment with phorbol ester, stimulation of [3H]thymidine uptake by LTD4 was greatly inhibited. Moreover, treatment of the cells by LTD4 resulted in a time-dependent increase of cytosolic PKC activity, whereas addition of phorbol 12-myristate 13-acetate reduced this activity. Therefore PKC-dependent mechanisms are likely to mediate the growth-promoting effect of LTD4. Finally, three approaches were used to determine the potential role of the Na+-H+ exchanger. First, progressive removal of extracellular Na+ using N-methyl-D-glucamine+ as a substitute inhibited LTD4-induced [3H]thymidine uptake with a 50% inhibitory concentration (IC50) of 85 mM. Second, addition of amiloride reduced the LTD4 growth effect with an IC50 of 6.5 microM, whereas three amiloride analogues exhibited lower IC50 values in accordance with their greater affinity for the Na+-H+ exchanger.(ABSTRACT TRUNCATED AT 250 WORDS)

Production and polarized secretion of basement membrane components by glomerular epithelial cells

1992 ◽  
Vol 262 (1) ◽  
pp. F131-F137 ◽  
Author(s):  
Y. Natori ◽  
Y. M. O'Meara ◽  
E. C. Manning ◽  
A. W. Minto ◽  
J. S. Levine ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Basement Membrane ◽  
Type Iv Collagen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Type Iv ◽  
Polarized Secretion ◽  
Glomerular Epithelial Cells ◽  
Basolateral Side ◽  
Membrane Components ◽  
Basement Membrane Components

To study the formation of basement membrane by glomerular epithelial cells (GECs), production and secretion of type IV collagen and laminin by rat GECs in culture were evaluated. GECs produced two chains of type IV collagen (180 and 170 kDa) in the ratio of approximately 2 to 1, when immunoprecipitated with antibody to type IV collagen of mouse Engelbreth-Holm-Swarm (EHS) sarcoma. GECs also produced proteins that were precipitated by antibody to EHS laminin, i.e., two bands each in the positions of the A and B chains of mouse laminin. On enzyme-linked immunosorbent assay (ELISA), type IV collagen and laminin were found mainly in the cell-associated fraction and in the subepithelial culture medium. Confluent GECs on membrane filters formed a tight barrier against the flux of macromolecules. Under these conditions, 80% of newly synthesized and secreted matrix proteins were detected in the basolateral medium. Moreover, treatment with ammonium chloride, which is known to affect polarized secretion, caused both type IV collagen and laminin to be secreted via the basolateral and apical surfaces in similar amounts. These results indicate that cultured GECs are polarized and that they produce and secrete basement membrane components via the basolateral side.

Effect of puromycin aminonucleoside on HSPG core protein content of glomerular epithelial cells

1988 ◽  
Vol 255 (4) ◽  
pp. F590-F596 ◽  
Author(s):  
B. S. Kasinath ◽  
A. K. Singh ◽  
Y. S. Kanwar ◽  
E. J. Lewis
Keyword(s):  
Protein Synthesis ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Heparan Sulfate ◽  
Protein Content ◽  
Glomerular Basement Membrane ◽  
Core Protein ◽  
Puromycin Aminonucleoside ◽  
The Core ◽  
Glomerular Epithelial Cells

It has been suggested that the glomerular basement membrane heparan sulfate proteoglycan (HSPG) is an important determinant of the glomerular permselectivity barrier. Derangements in the content of basement membrane heparan sulfate have been implicated in alterations in glomerular permselectivity seen in many glomerular diseases such as aminonucleoside nephrosis. The cellular origin and metabolism of the glomerular basement membrane HSPG have not been studied in detail. We have detected the expression of the proteoglycan by cloned glomerular visceral epithelial cells of the rat by employing a specific antibody against the core protein of HSPG isolated from the rat glomerular basement membrane. These findings suggest that in the rat in vivo glomerular visceral epithelial cells are one source of heparan sulfate present in the glomerular basement membrane. The effect of puromycin aminonucleoside (PAN) on the HSPG core protein content of the cloned glomerular epithelial cells was studied. By a quantitative immunoperoxidase method, the aminonucleoside caused a 28% reduction in the core protein content of the epithelial cells (P less than 0.01) following 72 h of incubation. However, the content of Heymann nephritis-related antigen, Fx1A was unchanged. Studies employing [3H]leucine incorporation showed that PAN was a weak inhibitor of de novo protein synthesis at 24 h of incubation, with complete recovery at 48 and 72 h. These data suggest that PAN effect on heparan sulfate core protein cannot be attributed to generalized inhibition of protein synthesis. The precise mechanism underlying the aminonucleoside effect on heparan sulfate core protein remains to be elucidated.

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