Moxonidine inhibits Na+/H+ exchange in proximal tubule cells and cortical collecting duct

Bcl-2 protects cells from apoptosis initiated by a variety of stimuli including loss of cell adhesion. Bcl-2 −/− mice develop renal hypoplastic/cystic dysplasia with renal cyst formation coinciding with renal maturation in normal mice. To gain a better understanding of the role cell-adhesive mechanisms play during renal maturation, we generated proximal tubule and collecting duct cell lines from postnatal day 10 ( P10) and P20 bcl-2 +/+ and bcl-2 −/− mice. Very little is known about the role cell-adhesive and migratory mechanisms play during renal maturation. We observed that modulation of cell-adhesive properties, which normally occur in a nephron segment-specific manner during renal maturation, and cell migration were altered in cells from bcl-2 −/− mice. Enhanced migration of bcl-2 −/− proximal tubule cells in a scratch wound assay was completely inhibited by incubation with PP1 (Src inhibitor) and moderately affected by incubation with SB-203580 (p38 inhibitor). These cells expressed increased levels of fibronectin and had numerous central focal adhesions. P20 bcl-2 −/− proximal tubule cells adhered to fibronectin but adhered poorly to collagen, vitronectin, or laminin. Collecting duct cells, similar to proximal tubule cells from bcl-2 −/− mice, demonstrated enhanced migration in a scratch wound assay that was inhibited by incubation with PP1. Migration of these cells was moderately affected by incubation with PD-98059 (MEK inhibitor) or LY-294002 (PI3 kinase inhibitor), whereas incubation with SB-203580 had no effect. P10 bcl-2 −/− collecting duct cells also expressed increased levels of fibronectin but decreased levels of thrombospondin-1 and demonstrated precocious binding to fibronectin and vitronectin compared with bcl-2 +/+ cells. The ability of P20 bcl-2 +/+ collecting duct cells to adhere to fibronectin and vitronectin corresponded with a decline in thrombospondin-1 expression. Therefore, alterations in cell-adhesive and migratory characteristics may be an early indicator of aberrant renal epithelial cell differentiation.

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Exosomal transfer from human renal proximal tubule cells to distal tubule and collecting duct cells

Clinical Biochemistry ◽

10.1016/j.clinbiochem.2014.06.018 ◽

2014 ◽

Vol 47 (15) ◽

pp. 89-94 ◽

Cited By ~ 42

Author(s):

John J. Gildea ◽

Joscelyn E. Seaton ◽

Ken G. Victor ◽

Camellia M. Reyes ◽

Dora Bigler Wang ◽

...

Keyword(s):

Proximal Tubule ◽

Collecting Duct ◽

Distal Tubule ◽

Renal Proximal Tubule ◽

Proximal Tubule Cells ◽

Duct Cells ◽

Collecting Duct Cells ◽

Tubule Cells ◽

Renal Proximal Tubule Cells

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Localization of Na(+)-dependent active type and erythrocyte/HepG2-type glucose transporters in rat kidney: immunofluorescence and immunogold study.

Journal of Histochemistry & Cytochemistry ◽

10.1177/39.3.1993828 ◽

1991 ◽

Vol 39 (3) ◽

pp. 287-298 ◽

Cited By ~ 64

Author(s):

K Takata ◽

T Kasahara ◽

M Kasahara ◽

O Ezaki ◽

H Hirano

Keyword(s):

Plasma Membrane ◽

Proximal Tubule ◽

Plasma Membranes ◽

Collecting Duct ◽

Facilitated Diffusion ◽

Frozen Sections ◽

Proximal Tubule Cells ◽

Henle's Loop ◽

Glomerular Filtrate ◽

Tubule Cells

Glucose is actively taken up from the glomerular filtrate into the tubule cells by the Na(+)-dependent active glucose transporter (GT), and passively crosses the basolateral membrane via facilitated diffusion GT. With the use of antibodies directed against two types of GTs, we show the immunocytochemical localization of the Na(+)-dependent active GT (SGLT1) and the erythrocyte/HepG2-type facilitated diffusion GT (GLUT1). For light microscopic observation, frozen sections were stained by the rhodamine labeling method. Counterstaining with fluorescein-phalloidin and 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) was employed to facilitate cell type identification. Immunogold staining was carried out on ultra-thin frozen sections for electron microscopy. The antibody to SGLT1 reacted with a 77 KD protein in immunoblotting of a kidney lysate. By immunocytochemistry, SGLT1 was localized in the microvillous plasma membrane in the apical brush borders of the cells of all three proximal tubule segments (S1, S2, and S3). The antibodies to GLUT1, a member of the facilitated diffusion GT family, were raised against human erythrocyte GT or synthetic oligopeptides derived from HepG2 GT, which reacted with a 48 KD protein in immunoblotting of the kidney lysate. GLUT1 was found at the basolateral plasma membranes of S3 proximal tubule cells, cells of the thick limb of Henle's loop, and collecting duct cells. Combined with known physiological data, our findings suggest that SGLT1 in the apical plasma membrane of the proximal tubule cells is responsible for the Na(+)-dependent active reabsorption of glucose from the glomerular filtrate. GLUT1 in the basolateral plasma membrane of S3 cells may transport reabsorbed glucose to the blood vessels. GLUT1 in the basolateral plasma membranes of cells of the thick limb of Henle's loop and of the collecting duct, on the other hand, may nourish these metabolically active cells by facilitating the diffusion of extracellular glucose provided from blood through the basolateral side of the cells.

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Heterogeneous localization of G protein alpha-subunits in rat kidney

AJP Renal Physiology ◽

10.1152/ajprenal.1991.261.5.f831 ◽

1991 ◽

Vol 261 (5) ◽

pp. F831-F840 ◽

Cited By ~ 8

Author(s):

J. L. Stow ◽

I. Sabolic ◽

D. Brown

Keyword(s):

Proximal Tubule ◽

G Protein ◽

Collecting Duct ◽

Rat Kidney ◽

Thick Ascending Limb ◽

Heterogeneous Distribution ◽

Proximal Tubule Cells ◽

Alpha Subunits ◽

Tubule Cells ◽

Gs Alpha

The Gs alpha and Gi alpha 1-3 subunits of GTP-binding proteins were localized in sections of rat kidney using antibodies against unique synthetic decapeptides from the different G alpha subunits. All of the G alpha subunits were found to have a polarized distribution on renal tubule epithelial cells, and staining was typically found on either basolateral or apical membranes in a given cell type. Gi alpha 1 was localized to the apical pole of both thick ascending limb cells and cells forming the papillary epithelium, Gi alpha 2 labeled the basolateral plasma membrane and the cytoplasm of collecting duct principal cells, and Gi alpha 3 was most abundant in the apical region of proximal tubule cells of the S1 segment, where it was concentrated in sub-brush-border invaginations. It was also found in the perinuclear Golgi complex in these cells. Gs alpha was heavily concentrated on the basolateral plasma membranes of thick ascending limb cells and both principal and intercalated cells of the collecting duct. Less intense subapical staining of G alpha s was also found in proximal tubule cells. The cells of the macula densa had a unique G protein distribution that was distinct from the surrounding cells of the thick ascending limb of Henle. Antibodies specific for the Gi alpha 1 and Gi alpha 3 subunits both stained intracellular vesicles clustered at the basal pole of the cell. A heterogeneous distribution of G alpha subunits was also found by Western blotting on isolated cortical membrane fractions.

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Faculty Opinions recommendation of Mitochondrial aquaporin-8 in renal proximal tubule cells: evidence for a role in the response to metabolic acidosis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717948404.793453455 ◽

2012 ◽

Author(s):

Jeff Kraut

Keyword(s):

Metabolic Acidosis ◽

Proximal Tubule ◽

Renal Proximal Tubule ◽

Proximal Tubule Cells ◽

Tubule Cells ◽

Renal Proximal Tubule Cells

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Nephrotoxicity Testing In Vitro: The Current Situation

Alternatives to Laboratory Animals ◽

10.1177/026119299702500506 ◽

1997 ◽

Vol 25 (5) ◽

pp. 497-503

Author(s):

Jean-Paul Morin ◽

Marc E. De Broe ◽

Walter Pfaller ◽

Gabriele Schmuck

Keyword(s):

Proximal Tubule ◽

Culture Media ◽

Task Force ◽

Primary Cultures ◽

Phenotypic Expression ◽

Transepithelial Transport ◽

Specific Cell ◽

Proximal Tubule Cells ◽

Tubule Cells

An ECVAM task force on nephrotoxicity has been established to advise, in particular, on the follow-up to recommendations made in the ECVAM workshop report on nephrotoxicity testing in vitro. Since this workshop was held, in 1994, there have been several improvements in the techniques used. For example, the duration of renal slice viability, and the maintenance of functional activities in slices, have been improved by using dynamic incubation systems with higher oxygen tensions and more-appropriate cell culture media. Highly differentiated primary cultures of pig, human and rabbit proximal tubule cells have been established by using specific cell isolation procedures and/or selective culture media. To date, the most comparable phenotypic expression and transepithelial transport capacities to proximal tubules in vivo have been obtained with primary cultures of rabbit proximal tubule cells which are grown on bicompartmental supports; in this system, transepithelial substrate gradients are generated and the transepithelial transport of both organic anions and cations is highly active. This in vitro system has been selected by ECVAM for further evaluation and prevalidation. Industrial needs in the area of nephrotoxicity testing have been identified, and recommendations are made at the end of this report concerning possible future initiatives.

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