scholarly journals An ion-transporting ATPase encodes multiple apical localization signals.

1993 ◽  
Vol 121 (2) ◽  
pp. 283-293 ◽  
Author(s):  
C J Gottardi ◽  
M J Caplan
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Endocytic Pathway ◽  
Gastric Epithelium ◽  
Beta Subunits ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Molecular Signals ◽  
Apical Localization

Epithelial cells accumulate distinct populations of membrane proteins at their two plasmalemmal domains. We have examined the molecular signals which specify the differential subcellular distributions of two closely related ion pumps. The Na,K-ATPase is normally restricted to the basolateral membranes of numerous epithelial cell types, whereas the H,K-ATPase is a component of the apical surfaces of the parietal cells of the gastric epithelium. We have expressed full length and chimeric H,K-ATPase/Na,K-ATPase cDNAs in polarized renal proximal tubular epithelial cells (LLC-PK1). We find that both the alpha and beta subunits of the H,K-ATPase encode independent signals that specify apical localization. Furthermore, the H,K-ATPase beta-subunit possesses a sequence which mediates its participation in the endocytic pathway. The interrelationship between epithelial sorting and endocytosis signals suggested by these studies supports the redefinition of apical and basolateral as functional, rather than simply topographic domains.

Reabsorption of native and glycated albumin by renal proximal tubular epithelial cells

1996 ◽  
Vol 271 (2) ◽  
pp. F261-F268 ◽  
Author(s):  
M. Bendayan ◽  
I. Londono
Keyword(s):  
Epithelial Cells ◽  
Glomerular Filtration ◽  
Glycated Albumin ◽  
Basement Membranes ◽  
Endocytic Pathway ◽  
Tubular Epithelial Cells ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Urinary Space

The proximal tubule epithelial handling of native and glycated albumin was evaluated by quantitative immunocytochemistry. Native bovine serum albumin (BSA) and its glycated form (gBSA), tagged to different haptens, were simultaneously injected in anesthetized mice and maintained in circulation for 10 or 60 min. Both albumins were localized within the capillary lumen, in glomerular and peritubular basement membranes, the urinary space, and cellular compartments of the proximal tubular epithelial cells. In these cells, both forms of albumin were concomitantly found within the same endocytic-lysosomal system. Morphometric evaluations have indicated higher proportions of gBSA in the urinary space, reflecting probably a significant glomerular filtration of this form of albumin combined to a lesser reabsorptive clearance. Indeed, higher proportions of native BSA were found in the endocytic compartment of the tubular epithelial cells, suggesting its preferential reabsorption. The present study thus supports a preferential glomerular filtration of gBSA with a facilitated filtration of native BSA in the presence of the glycated one. It also demonstrates the tubular reabsorption of BSA and gBSA through a common endocytic pathway, in which the native BSA is preferentially reabsorbed with respect to its glycated form.

Is there a role of cyclosporine A on total homocysteine export from human renal proximal tubular epithelial cells?

2001 ◽  
Vol 59 (s78) ◽  
pp. 258-261 ◽  
Author(s):  
Mihaela C. Ignatescu ◽  
Manuela Fodiger ◽  
Josef Kletzmayr ◽  
Christian Bieglmayer ◽  
Walter H. Horl ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cyclosporine A ◽  
Tubular Epithelial Cells ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Total Homocysteine ◽  
Renal Proximal Tubular

scholarly journals LincRNA-p21 Inhibits Cisplatin-Induced Apoptosis of Human Renal Proximal Tubular Epithelial Cells by Sponging miR-449a

2021 ◽  
pp. 1-7
Author(s):  
Zhen Li ◽  
Gang Hou
Keyword(s):  
Breast Cancer ◽  
Epithelial Cells ◽  
Kidney Injury ◽  
Protective Role ◽  
Tubular Epithelial Cells ◽  
Breast Cancer Patients ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Induced Apoptosis

<b><i>Introduction:</i></b> LincRNA-p21 is predicted to interact with miR-449a, which plays a protective role in cisplatin-induced acute kidney injury (CIA). <b><i>Objective:</i></b> This study aimed to analyze the involvement of lincRNA-p21 in breast cancer patients with CIA. <b><i>Methods:</i></b> Levels of lincRNA-p21 in plasma from CIA, triple negative breast cancer, and control groups were measured by performing RT-qPCR. The potential interaction between lincRNA-p21 and miR-449a was first predicted by RT-qPCR. The relationship between lincRNA-p21 and miR-449a was analyzed by overexpression experiment. <b><i>Results:</i></b> We found that lincRNA-p21 is downregulated in CIA. Dual luciferase activity assay showed that lincRNA-p21 and miR-449a can interact with each other, while overexpression of lincRNA-p21 and miR-449a failed to affect the expression of each other. In human renal proximal tubular epithelial cells (HRPTEpCs), cisplatin led to the upregulated miR-449a but downregulated lincRNA-p21. Interestingly, lincRNA-p21 overexpression led to reduced enhancing effects of miR-449a on the cisplatin-induced apoptosis of HRPTEpCs. <b><i>Conclusion:</i></b> Therefore, lincRNA-p21 is downregulated in CIA and may sponge miR-449a to inhibit cisplatin-induced apoptosis of HRPTEpCs.

scholarly journals Urine-Derived Epithelial Cells as Models for Genetic Kidney Diseases

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1413
Author(s):  
Tjessa Bondue ◽  
Fanny O. Arcolino ◽  
Koenraad R. P. Veys ◽  
Oyindamola C. Adebayo ◽  
Elena Levtchenko ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Kidney Diseases ◽  
Cell Types ◽  
Cell Models ◽  
Tubular Epithelial Cells ◽  
Disease Mechanisms ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Disease Cell

Epithelial cells exfoliated in human urine can include cells anywhere from the urinary tract and kidneys; however, podocytes and proximal tubular epithelial cells (PTECs) are by far the most relevant cell types for the study of genetic kidney diseases. When maintained in vitro, they have been proven extremely valuable for discovering disease mechanisms and for the development of new therapies. Furthermore, cultured patient cells can individually represent their human sources and their specific variants for personalized medicine studies, which are recently gaining much interest. In this review, we summarize the methodology for establishing human podocyte and PTEC cell lines from urine and highlight their importance as kidney disease cell models. We explore the well-established and recent techniques of cell isolation, quantification, immortalization and characterization, and we describe their current and future applications.

Mechanisms underlying induction of heme oxygenase-1 by nitric oxide in renal tubular epithelial cells

2000 ◽  
Vol 279 (4) ◽  
pp. F728-F735 ◽  
Author(s):  
Mingyu Liang ◽  
Anthony J. Croatt ◽  
Karl A. Nath
Keyword(s):  
Nitric Oxide ◽  
Epithelial Cells ◽  
Sodium Nitroprusside ◽  
Nitric Oxide Donor ◽  
Heme Oxygenase 1 ◽  
Tubular Epithelial Cells ◽  
Cytotoxic Effects ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Renal Proximal Tubular

We examined whether nitric oxide-generating agents influence expression of heme oxygenase-1 (HO-1) in renal proximal tubular epithelial cells, LLC-PK1 cells, and the mechanisms underlying any such effects. In sublytic amounts, the nitric oxide donor sodium nitroprusside induced HO-1 mRNA and protein and HO activity in a dose-dependent and time-dependent fashion; this induction was specific for nitric oxide since the nitric oxide scavenger carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide significantly reduced such induction. The induction of HO activity by sodium nitroprusside, or by another nitric oxide donor, spermine NONOate, was markedly reduced by the iron chelator deferoxamine. Two different thiol-containing agents, N-acetylcysteine and dithiothreitol, blunted such induction of HO by nitric oxide. Downstream products of nitric oxide, such as peroxynitrite or cGMP, were not involved in inducing HO. In higher concentrations (millimolar amounts), sodium nitroprusside induced appreciable cytotoxicity as assessed by lactate dehydrogenase (LDH) release and lipid peroxidation, and both of these effects were markedly reduced by deferoxamine. Inhibition of HO did not affect the cytotoxic effects (measured by LDH release) of sodium nitroprusside. We thus provide the novel description of the induction of HO-1 in renal proximal tubular epithelial cells exposed to nitric oxide donors and provide the first demonstration in kidney-derived cells for the involvement of a redox-based mechanism in such expression. We also demonstrate that, in LLC-PK1 cells exposed to nitric oxide donors, chelatable iron is involved in eliciting the HO-1 response observed at lower concentrations of these donors, and in mediating the cytotoxic effects of these donors when present in higher concentrations.

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