scholarly journals A role for collecting duct epithelial cells in renal antibacterial defences

2011 ◽  
Vol 13 (8) ◽  
pp. 1107-1113 ◽  
Author(s):  
Cecilia Chassin ◽  
Emilie Tourneur ◽  
Marcelle Bens ◽  
Alain Vandewalle
Keyword(s):  
Epithelial Cells ◽  
Collecting Duct

scholarly journals c-Src inactivation reduces renal epithelial cell-matrix adhesion, proliferation, and cyst formation

2011 ◽  
Vol 301 (2) ◽  
pp. C522-C529 ◽  
Author(s):  
Justine Elliott ◽  
Nadezhda N. Zheleznova ◽  
Patricia D. Wilson
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Collecting Duct ◽  
Specific Inhibitor ◽  
Cell Phenotype ◽  
Epithelial Cell Proliferation ◽  
Matrix Adhesion ◽  
Cyst Lining

c-Src is a non-receptor tyrosine kinase whose activity is induced by phosphorylation at Y418 and translocation from the cytoplasm to the cell membrane. Increased activity of c-Src has been associated with cell proliferation, matrix adhesion, motility, and apoptosis in tumors. Immunohistochemistry suggested that activated (pY418)-Src activity is increased in cyst-lining autosomal dominant polycystic kidney disease (ADPKD) epithelial cells in human and mouse ADPKD. Western blot analysis showed that SKI-606 (Wyeth) is a specific inhibitor of pY418-Src without demonstrable effects on epidermal growth factor receptor or ErbB2 activity in renal epithelia. In vitro studies on mouse inner medullary collecting duct (mIMCD) cells and human ADPKD cyst-lining epithelial cells showed that SKI-606 inhibited epithelial cell proliferation over a 24-h time frame. In addition, SKI-606 treatment caused a striking statistically significant decrease in adhesion of mIMCD and human ADPKD to extracellular collagen matrix. Retained viability of unattached cells was consistent with a primary effect on epithelial cell anchorage dependence mediated by the loss of extracellular matrix (ECM)-attachment due to α2β1-integrin function. SKI-606-mediated attenuation of the human ADPKD hyperproliferative and hyper-ECM-adhesive epithelial cell phenotype in vitro was paralleled by retardation of the renal cystic phenotype of Pkd1 orthologous ADPKD heterozygous mice in vivo. This suggests that SKI-606 has dual effects on cystic epithelial cell proliferation and ECM adhesion and may have therapeutic potential for ADPKD patients.

scholarly journals Localization of phosphatidylinositol phosphate kinase IIγ in kidney to a membrane trafficking compartment within specialized cells of the nephron

2008 ◽  
Vol 295 (5) ◽  
pp. F1422-F1430 ◽  
Author(s):  
Jonathan H. Clarke ◽  
Piers C. Emson ◽  
Robin F. Irvine
Keyword(s):  
Epithelial Cells ◽  
Membrane Trafficking ◽  
Kidney Cell ◽  
Collecting Duct ◽  
Thick Ascending Limb ◽  
Phosphatidylinositol Phosphate ◽  
The Matrix ◽  
Phosphatidylinositol 4

PIP4Ks (type II phosphatidylinositol 4-phosphate kinases) are phosphatidylinositol 5-phosphate (PtdIns5P) 4-kinases, believed primarily to regulate cellular PtdIns5P levels. In this study, we investigated the expression, localization, and associated biological activity of the least-studied PIP4K isoform, PIP4Kγ. Quantitative RT-PCR and in situ hybridization revealed that compared with PIP4Kα and PIP4Kβ, PIP4Kγ is expressed at exceptionally high levels in the kidney, especially the cortex and outer medulla. A specific antibody was raised to PIP4Kγ, and immunohistochemistry with this and with antibodies to specific kidney cell markers showed a restricted expression, primarily distributed in epithelial cells in the thick ascending limb and in the intercalated cells of the collecting duct. In these cells, PIP4Kγ had a vesicular appearance, and transfection of kidney cell lines revealed a partial Golgi localization (primarily the matrix of the cis-Golgi) with an additional presence in an unidentified vesicular compartment. In contrast to PIP4Kα, bacterially expressed recombinant PIP4Kγ was completely inactive but did have the ability to associate with active PIP4Kα in vitro. Overall our data suggest that PIP4Kγ may have a function in the regulation of vesicular transport in specialized kidney epithelial cells.

scholarly journals Differential expression and targeting of endogenous Arf1 and Arf6 small GTPases in kidney epithelial cells in situ

2004 ◽  
Vol 286 (4) ◽  
pp. C768-C778 ◽  
Author(s):  
Jaafar El Annan ◽  
Dennis Brown ◽  
Sylvie Breton ◽  
Sylvain Bourgoin ◽  
Dennis A. Ausiello ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Western Blotting ◽  
Collecting Duct ◽  
Small Gtpases ◽  
Renal Physiology ◽  
Principal Cells ◽  
Arf Gtpases ◽  
Kidney Epithelial Cells

ADP-ribosylation factors (Arfs) are small GTPases that regulate vesicular trafficking in exo- and endocytotic pathways. As a first step in understanding the role of Arfs in renal physiology, immunocytochemistry and Western blotting were performed to characterize the expression and targeting of Arf1 and Arf6 in epithelial cells in situ. Arf1 and Arf6 were associated with apical membranes and subapical vesicles in proximal tubules, where they colocalized with megalin. Arf1 was also apically expressed in the distal tubule, connecting segment, and collecting duct (CD). Arf1 was abundant in intercalated cells (IC) and colocalized with V-ATPase in A-IC (apical) and B-IC (apical and/or basolateral). In contrast, Arf6 was associated exclusively with basolateral membranes and vesicles in the CD. In the medulla, basolateral Arf6 was detectable mainly in A-IC. Expression in principal cells became weaker throughout the outer medulla, and Arf6 was not detectable in principal cells in the inner medulla. In some kidney epithelial cells Arf1 but not Arf6 was also targeted to a perinuclear patch, where it colocalized with TGN38, a marker of the trans-Golgi network. Quantitative Western blotting showed that expression of endogenous Arf1 was 26–180 times higher than Arf6. These data indicate that Arf GTPases are expressed and targeted in a cell- and membrane-specific pattern in kidney epithelial cells in situ. The results provide a framework on which to base and interpret future studies on the role of Arf GTPases in the multitude of cellular trafficking events that occur in renal tubular epithelial cells.

Expression of mRNA for natriuretic peptide receptor subtypes in bovine kidney

1994 ◽  
Vol 267 (2) ◽  
pp. F318-F324 ◽  
Author(s):  
T. Yamamoto ◽  
L. Feng ◽  
T. Mizuno ◽  
S. Hirose ◽  
K. Kawasaki ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Natriuretic Peptide ◽  
Collecting Duct ◽  
Biologically Active ◽  
Ribonuclease Protection Assay ◽  
Receptor Subtypes ◽  
Total Rna ◽  
Duct Cells ◽  
Glomerular Epithelial Cells ◽  
Collecting Duct Cells

The localization of mRNA for atrial natriuretic peptide (ANP) receptor subtypes (A, B, C) in the kidney was examined. Quantitative analysis of the ribonuclease protection assay showed that the numbers of type A receptor (ANPRA) mRNA were 6.9 x 10(7) in the glomeruli and 10.4 x 10(7) molecules/micrograms of total RNA in the inner medulla, and that of type C receptor (ANPRC) mRNA was 21.7 x 10(7) molecules/micrograms of total RNA in the glomeruli. The type B receptor (ANPRB) mRNA was present in smaller numbers (4.5-4.9 x 10(6) molecules/micrograms of total RNA) evenly throughout the kidney fractions. In situ hybridization demonstrated both ANPRA and ANPRC mRNA selectively in the glomerular epithelial cells and ANPRA mRNA in the collecting duct cells of the inner medulla. ANPRC was also localized on the foot processes of glomerular epithelial cells by immunohistochemistry using a specific antibody against the receptor. These results indicate that ANPRA is the major biologically active receptor for the ANP family of hormones in the kidney and is present selectively on the glomerular epithelial cells and inner medullary collecting duct cells. These cells are presumed to play a role in the regulation of glomerular filtration rate and sodium excretion induced by the family of ANP.

scholarly journals Large-scale phosphotyrosine proteomic profiling of rat renal collecting duct epithelium reveals predominance of proteins involved in cell polarity determination

2012 ◽  
Vol 302 (1) ◽  
pp. C27-C45 ◽  
Author(s):  
Boyang Zhao ◽  
Mark A. Knepper ◽  
Chung-Lin Chou ◽  
Trairak Pisitkun
Keyword(s):  
Epithelial Cells ◽  
Tyrosine Phosphorylation ◽  
Metal Ion ◽  
Large Scale ◽  
Collecting Duct ◽  
Affinity Purification ◽  
Large Fraction ◽  
Proteomic Profiling ◽  
Data Set ◽  
Polarity Determination

Although extensive phosphoproteomic information is available for renal epithelial cells, previous emphasis has been on phosphorylation of serines and threonines with little focus on tyrosine phosphorylation. Here we have carried out large-scale identification of phosphotyrosine sites in pervanadate-treated native inner medullary collecting ducts of rat, with a view towards identification of physiological processes in epithelial cells that are potentially regulated by tyrosine phosphorylation. The method combined antibody-based affinity purification of tyrosine phosphorylated peptides coupled with immobilized metal ion chromatography to enrich tyrosine phosphopeptides, which were identified by LC-MS/MS. A total of 418 unique tyrosine phosphorylation sites in 273 proteins were identified. A large fraction of these sites have not been previously reported on standard phosphoproteomic databases. All results are accessible via an online database: http://helixweb.nih.gov/ESBL/Database/iPY/ . Analysis of surrounding sequences revealed four overrepresented motifs: [D/E]xxY*, Y*xxP, DY*, and Y*E, where the asterisk symbol indicates the site of phosphorylation. These motifs plus contextual information, integrated using the NetworKIN tool, suggest that the protein tyrosine kinases involved include members of the insulin- and ephrin-receptor kinase families. Analysis of the gene ontology (GO) terms and KEGG pathways whose protein elements are overrepresented in our data set point to structures involved in epithelial cell-cell and cell-matrix interactions (“adherens junction,” “tight junction,” and “focal adhesion”) and to components of the actin cytoskeleton as major sites of tyrosine phosphorylation in these cells. In general, these findings mesh well with evidence that tyrosine phosphorylation plays a key role in epithelial polarity determination.

scholarly journals ASC in Renal Collecting Duct Epithelial Cells Contributes to Inflammation and Injury after Unilateral Ureteral Obstruction

2014 ◽  
Vol 184 (5) ◽  
pp. 1287-1298 ◽  
Author(s):  
Takanori Komada ◽  
Fumitake Usui ◽  
Koumei Shirasuna ◽  
Akira Kawashima ◽  
Hiroaki Kimura ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Ureteral Obstruction ◽  
Collecting Duct ◽  
Unilateral Ureteral Obstruction ◽  
Renal Collecting Duct

Suppression of HGF receptor gene expression by oxidative stress is mediated through the interplay between Sp1 and Egr-1

2003 ◽  
Vol 284 (6) ◽  
pp. F1216-F1225 ◽  
Author(s):  
Xianghong Zhang ◽  
Youhua Liu
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Collecting Duct ◽  
Receptor Gene ◽  
Ectopic Expression ◽  
Transcriptional Activator ◽  
Physical Interaction ◽  
Nucleotide Position ◽  
Renal Epithelial Cells ◽  
Cis Acting

Hepatocyte growth factor (HGF) receptor, the product of the c-metprotooncogene, is transcriptionally regulated by a wide variety of cytokines as well as extracellular environmental cues. In this report, we demonstrate that c-met expression was significantly suppressed by oxidative stress. Treatment of mouse renal inner medullary collecting duct epithelial cells with 0.5 mM H2O2inhibited c-met mRNA and protein expression, which was concomitant with induction of Egr-1 transcription factor. Ectopic expression of Egr-1 in renal epithelial cells markedly inhibited endogenous c-met expression in a dose-dependent fashion, suggesting a causative effect of Egr-1 in mediating c-met suppression. The cis-acting element responsible for H2O2-induced c-met inhibition was localized at nucleotide position −223 to −68 of c-met promoter, in which reside an imperfect Egr-1 and three Sp1-binding sites. Egr-1 markedly suppressed c-met promoter activity but did not directly bind to its cis-acting element in the c-met gene. Induction of Egr-1 by oxidative stress attenuated the binding of Sp1 to its cognate sites, but it did not affect Sp1 abundance in renal epithelial cells. Immunoprecipitation uncovered that Egr-1 physically interacted with Sp1 by forming the Sp1/Egr-1 complex, which presumably resulted in a decreased availability of unbound Sp1 as a transcriptional activator for the c-met gene. Thus it appears that inhibition of c-met expression by oxidative stress is mediated by the interplay between Sp1 and Egr-1 transcription factors. Our findings reveal a novel transcriptional regulatory mechanism by which Egr-1 sequesters Sp1 as a transcriptional activator of c-met via physical interaction.

Cell volume regulation of rat kidney collecting duct epithelial cells in hypotonic medium

2011 ◽  
Vol 436 (1) ◽  
pp. 13-15 ◽  
Author(s):  
E. I. Solenov ◽  
G. S. Baturina ◽  
A. V. Ilyaskin ◽  
L. Ye. Katkova ◽  
L. N. Ivanova
Keyword(s):  
Epithelial Cells ◽  
Cell Volume ◽  
Volume Regulation ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Cell Volume Regulation ◽  
Hypotonic Medium ◽  
Kidney Collecting Duct

scholarly journals Clint: A Novel Clathrin-binding ENTH-Domain Protein at the Golgi

2002 ◽  
Vol 13 (11) ◽  
pp. 4060-4073 ◽  
Author(s):  
Christoph Kalthoff ◽  
Stephanie Groos ◽  
Rüdiger Kohl ◽  
Stefan Mahrhold ◽  
Ernst J. Ungewickell
Keyword(s):  
Epithelial Cells ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Coated Vesicles ◽  
Apical Region ◽  
Interacting Protein ◽  
Enth Domain ◽  
Rich Domain ◽  
Golgi Region ◽  
Domain Protein

We have characterized a novel clathrin-binding 68-kDa epsin N-terminal homology domain (ENTH-domain) protein that we name clathrin interacting protein localized in the trans-Golgi region (Clint). It localizes predominantly to the Golgi region of epithelial cells as well as to more peripheral vesicular structures. Clint colocalizes with AP-1 and clathrin only in the perinuclear area. Recombinantly expressed Clint interacts directly with the γ-appendage domain of AP-1, with the clathrin N-terminal domain through the peptide motif 423LFDLM, with the γ-adaptin ear homology domain of Golgi-localizing, γ-adaptin ear homology domain 2, with the appendage domain of β2-adaptin and to a lesser extent with the appendage domain of α-adaptin. Moreover, the Clint ENTH-domain asssociates with phosphoinositide-containing liposomes. A significant amount of Clint copurifies with rat liver clathrin-coated vesicles. In rat kidney it is preferentially expressed in the apical region of epithelial cells that line the collecting duct. Clathrin and Clint also colocalize in the apical region of enterocytes along the villi of the small intestine. Apart from the ENTH-domain Clint has no similarities with the epsins AP180/CALM or Hip1/1R. A notable feature of Clint is a carboxyl-terminal methionine-rich domain (Met427-Met605), which contains >17% methionine. Our results suggest that Clint might participate in the formation of clathrin-coated vesicles at the level of thetrans-Golgi network and remains associated with the vesicles longer than clathrin and adaptors.

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