scholarly journals Epidermal Growth Factor‐Induced Phosphorylation Changes in Rat Inner Medullary Collecting Duct

2019 ◽  
Vol 33 (S1) ◽  
Author(s):  
Chung‐Lin Chou ◽  
Mark A Knepper
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Collecting Duct ◽  
Inner Medullary Collecting Duct ◽  
Epidermal Growth ◽  
Medullary Collecting Duct

Response of rat inner medullary collecting duct to epidermal growth factor

1989 ◽  
Vol 256 (6) ◽  
pp. F1117-F1124 ◽  
Author(s):  
R. C. Harris
Keyword(s):  
Growth Factor ◽  
Binding Sites ◽  
Collecting Duct ◽  
Affinity Binding ◽  
Inner Medullary Collecting Duct ◽  
Duct Cells ◽  
Epidermal Growth ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct

Urine is an abundant source of epidermal growth factor (EGF) and prepro-EGF has been localized to the thick ascending limb and distal convoluted tubule of the kidney. However, the functional role of EGF in the kidney is poorly understood. Determination of EGF receptors and functional responses to EGF in intrarenal structures distal to the site of renal EGF production may prove critical to our understanding of the role of this peptide. These studies were designed to investigate the response to EGF of rat inner medullary collecting duct cells in culture and in freshly isolated suspensions. Primary cultures of inner medullary collecting duct cells demonstrated equilibrium binding of 125I-labeled EGF at 4 and 23 degrees C. At 23 degrees C, there was 89 +/- 1% specific binding (n = 30). Scatchard analysis of 125I-EGF binding suggested the presence of both high-affinity binding with a dissociation constant (Kd) of 5 X 10(-10) M and maximal binding sites (Ro) of 2.7 X 10(3) binding sites/cell and low-affinity binding, with Kd of 8.3 X 10(-9) M and Ro of 1.8 X 10(4) binding sites/cell. Bound EGF, 68 +/- 3%, was internalized by 45 min. EGF binding was not inhibited by antidiuretic hormone, atrial natriuretic peptide or bradykinin at 23 degrees C, but there was concentration-dependent inhibition of binding by transforming growth factor-alpha. Incubation with phorbol myristate acetate decreased 125I-EGF binding in a concentration-dependent manner. 125I-EGF binding was also demonstrated in freshly isolated suspensions of rat inner medullary collecting duct cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal tubular cells are potential targets for epidermal growth factor

1988 ◽  
Vol 255 (6) ◽  
pp. F1191-F1196 ◽  
Author(s):  
P. R. Goodyer ◽  
Z. Kachra ◽  
C. Bell ◽  
R. Rozen
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Line ◽  
Binding Sites ◽  
Collecting Duct ◽  
Primary Cultures ◽  
Kidney Cortex ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Epidermal Growth

Epidermal growth factor (EGF) is a potent polypeptide mitogen with various receptor-mediated growth effects on cells from the skin, breast, and gastrointestinal tract. Recent studies indicate that EGF is produced in the kidney and is excreted in the urine, but the biological significance of renal EGF is uncertain. We demonstrate in vitro mitogenicity of EGF for LLC-PK1 cells, a tubular epithelial cell line derived from pig kidney cortex. Furthermore, when subconfluent monolayers of LLC-PK1 cells are exposed to EGF for 24 h, sodium-dependent phosphate transport is stimulated (209-410% of control). These cells possess EGF-specific high-affinity binding sites at their surface (Kd 300-700 pM) but cannot synthesize the growth factor. EGF binding sites are not a peculiarity of the LLC-PK1 cell line, since similar sites are present on MDCK cells (derived from dog kidney distal tubule or collecting duct), primary cultures of mouse proximal tubular cells, and freshly prepared membrane fractions from mouse kidney. Cortical basolateral membranes are highly enriched in EGF binding sites, whereas EGF binding by brush-border membrane fractions is minimal and is compatible with contamination.

scholarly journals Epidermal growth factor-induced proliferation of collecting duct cells from Oak Ridge polycystic kidney mice involves activation of Na+/H+ exchanger

2014 ◽  
Vol 307 (6) ◽  
pp. C554-C560 ◽  
Author(s):  
Sonya D. Coaxum ◽  
Mary G. Blanton ◽  
Alisha Joyner ◽  
Tanjina Akter ◽  
P. Darwin Bell ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Line ◽  
Cell Lines ◽  
Egf Receptor ◽  
Collecting Duct ◽  
Polycystic Kidney ◽  
Oak Ridge ◽  
Erk Phosphorylation ◽  
Epidermal Growth

Epidermal growth factor (EGF) is linked to the pathogenesis of polycystic kidney disease (PKD). We explored signaling pathways activated by EGF in orpk cilia (−) collecting duct cell line derived from a mouse model of PKD (hypomorph of the Tg737/ Ift88 gene) with severely stunted cilia, and in a control orpk cilia (+) cell line with normal cilia. RT-PCR demonstrated mRNAs for EGF receptor subunits ErbB1, ErbB2, ErbB3, ErbB4, and mRNAs for Na+/H+ exchangers (NHE), NHE-1, NHE-2, NHE-3, NHE-4, and NHE-5 in both cell lines. EGF stimulated proton efflux in both cell lines. This effect was significantly attenuated by MIA, 5-( n-methyl- N-isobutyl) amiloride, a selective inhibitor of NHE-1 and NHE-2, and orpk cilia (−) cells were more sensitive to MIA than control cells ( P < 0.01). EGF significantly induced extracellular signal-regulated kinase (ERK) phosphorylation in both cilia (+) and cilia (−) cells (63.3 and 123.6%, respectively), but the effect was more pronounced in orpk cilia (−) cells ( P < 0.01). MIA significantly attenuated EGF-induced ERK phosphorylation only in orpk cilia (−) cells ( P < 0.01). EGF increased proliferation of orpk cilia (+) cells and orpk cilia (−) cells, respectively, and MIA at 1–5 μM attenuated EGF-induced proliferation in orpk cilia (−) cells without affecting proliferation of orpk cilia (+) cells. EGF-induced proliferation of both cell lines was significantly decreased by the EGFR tyrosine kinase inhibitor AG1478 and MEK inhibitor PD98059. These results suggest that EGF exerts mitogenic effects in the orpk cilia (−) cells via activation of growth-associated amiloride-sensitive NHEs and ERK.

Site and mechanism of action of epidermal growth factor in rabbit cortical collecting duct

1991 ◽  
Vol 260 (2) ◽  
pp. F163-F169 ◽  
Author(s):  
S. Muto ◽  
H. Furuya ◽  
K. Tabei ◽  
Y. Asano
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mechanism Of Action ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Membrane Voltage ◽  
Rabbit Kidney ◽  
Cortical Collecting Duct ◽  
Epidermal Growth

To examine the exact target cell and mechanism of action of epidermal growth factor (EGF) in the isolated cortical collecting duct from rabbit kidney, we compared electrical properties of collecting duct (CD) cells (principal cells) and intercalated (IC) cells in absence and presence of EGF at 10(-8) M. Differentiation of CD and IC cells was based on values of basolateral membrane voltage (Vb) and fractional apical membrane resistance (fRa). In CD cells, upon addition of EGF to bath, lumen-negative transepithelial voltage (VT) was decreased from -8.0 +/- 1.9 to -2.4 +/- 1.3 mV (n = 22, P less than 0.001), but Vb was little changed (from -85.1 +/- 2.8 to -83.1 +/- 2.7 mV, n = 19), indicating that EGF in bath mainly caused changes in apical membrane voltage. In addition, peritubular EGF increased transepithelial resistance (RT) from 132.9 +/- 15.8 to 153.8 +/- 18.4 omega.cm2 (n = 16, P less than 0.001) as well as fRa from 0.31 +/- 0.06 to 0.39 +/- 0.07 (n = 12, P less than 0.01). These actions of EGF were prevented by pretreatment with 50 microM luminal amiloride. Luminal EGF had no effects on VT, Vb, RT, or fRa of CD cells. In IC cells, upon addition of EGF to bath, neither Vb nor fRa was affected. From these results, we conclude that EGF acts on the CD cell at the basolateral border and inhibits mainly the amiloride-sensitive Na+ conductance in the apical membrane.

Epidermal growth factor and fluid and electrolyte balance in the rat

1997 ◽  
Vol 272 (6) ◽  
pp. R1853-R1861
Author(s):  
S. L. Grant ◽  
C. B. Gow ◽  
P. A. Phillips
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Intravenous Infusion ◽  
Collecting Duct ◽  
Urine Volume ◽  
Electrolyte Balance ◽  
Diuretic Effect ◽  
Sprague Dawley ◽  
Conscious Rat ◽  
Epidermal Growth

Epidermal growth factor (EGF) has been shown to induce a renal diuresis and natriuresis in sheep and stimulate prostaglandin synthesis from inner rat medullary collecting duct cells in culture. The aims of our study were 1) to investigate whether the renal effects of intravenous infusion of EGF were species specific and 2) to determine the mechanism of these effects by studying the interaction between EGF and indomethacin (a prostaglandin synthase inhibitor) in the conscious rat. Sprague-Dawley rats received intravenous infusions of either 0.9% saline or 0.2 or 2.0 micrograms EGF.kg-1.h-1 over a 6-day period after an initial baseline period. Infusion of 2.0 micrograms EGF.kg-1.h-1 caused an increase in urine volume (baseline: 5.5 +/- 0.2 ml to day 5: 9.0 +/- 0.4 ml, P < 0.01) and corresponding polydipsia, but not natriuresis. Administration of indomethacin with 2.0 micrograms EGF.kg-1.h-1 attenuated (P < 0.05) the diuretic (day 5 EGF + vehicle: 12.2 +/- 1.1 ml vs. EGF + indomethacin: 8.7 +/- 0.9 ml) and polydipsic effects of EGF. These studies demonstrate that intravenous infusion of EGF causes a diuretic effect in rats without natriuresis and that prostaglandins play a role in the diuretic effect of EGF in the rat.

scholarly journals Soluble HB-EGF induces epithelial-to-mesenchymal transition in inner medullary collecting duct cells by upregulating Snail-2

2009 ◽  
Vol 296 (5) ◽  
pp. F957-F965 ◽  
Author(s):  
James P. Smith ◽  
Ambra Pozzi ◽  
Punita Dhawan ◽  
Amar B. Singh ◽  
Raymond C. Harris
Keyword(s):  
Growth Factor ◽  
Renal Injury ◽  
Epithelial To Mesenchymal Transition ◽  
Collecting Duct ◽  
Acute Renal Injury ◽  
Mesenchymal Transition ◽  
Anchorage Independent Growth ◽  
Inner Medullary Collecting Duct ◽  
Medullary Collecting Duct ◽  
E Cadherin

Animal models of acute renal injury suggest that the epidermal growth factor receptor (EGFR) axis may have a beneficial role in the recovery from acute renal injury, but recent reports describe detrimental effects of EGFR activation in chronic renal injury. Expression of the EGFR ligand heparin-binding EGF-like growth factor (HB-EGF) increases following renal injury, but the effects of this sustained upregulation have not been well studied. Here, stable overexpression of soluble HB-EGF (sHB-EGF) in mouse inner medullary collecting duct (IMCD) cells led to marked phenotypic changes: sHB-EGF-expressing cells demonstrated a fibroblast-like morphology, did not form epithelial sheets, exhibited cytoplasmic projections, decreased expression of epithelial markers, and increased expression of fibroblast-specific protein-1. They also demonstrated anchorage-independent growth and formed tumors when injected subcutaneously into nude mice. Quantitative RT-PCR and a luciferase reporter assay suggested that sHB-EGF repressed transcription of E-cadherin, and a concomitant TGF-β-independent upregulation of the E-cadherin repressor Snail-2 was observed. Stable downregulation of Snail-2 in sHB-EGF-overexpressing cells restored epithelial characteristics (E-cadherin and cytokeratin expression) but did not alter their anchorage-independent growth. In summary, sustained exposure to sHB-EGF induces epithelial-to-mesenchymal transition of IMCD cells, in part by upregulating the E-cadherin transcriptional repressor Snail-2.

Induction of Collecting Duct MorphogenesisIn Vitroby Heparin-Binding Epidermal Growth Factor-Like Growth Factor

2001 ◽  
Vol 12 (5) ◽  
pp. 964-972
Author(s):  
TSUKASA TAKEMURA ◽  
SATOSHI HINO ◽  
HIROAKI KUWAJIMA ◽  
HIDEHIKO YANAGIDA ◽  
MITSURU OKADA ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Transforming Growth Factor ◽  
Collecting Duct ◽  
Transforming Growth Factor Β ◽  
Heparin Binding ◽  
Collagen Gels ◽  
Ureteric Bud ◽  
Kinase C ◽  
Epidermal Growth

Abstract. Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a member of the epidermal growth factor family of growth factors, is synthesized as a membrane-an-chored precursor (proHB-EGF) that is capable of stimulating adjacent cells in a juxtacrine manner. ProHB-EGF is cleaved in a protein kinase C-dependent process, to yield the soluble form. It was observed that HB-EGF acts as a morphogen for the collecting duct system in developing kidneys. HB-EGF protein was expressed in the ureteric bud of embryonic kidneys. Cultured mouse ureteric bud cells (UBC) produced HB-EGF via protein kinase C activation. After stimulation with phorbol ester (12-O-tetradecanoylphorbol-13-acetate) or recombinant soluble HB-EGF, UBC cultured in three-dimensional collagen gels formed short tubules with varied abundant branches. When proHB-EGF-transfected UBC were stimulated with 12-O-tetradecanoylphorbol-13-acetate and cultured in collagen gels, they exhibited linear growth, forming long tubular structures with few branches at the time of appearance of proHB-EGF on the cell surface. The structures exhibited a strong resemblance to the early branching ureteric bud of embryonic kidneys. When UBC were cultured in the presence of transforming growth factor-β and soluble HB-EGF, they formed long tubules and few branches, similar to the structures observed in proHB-EGF-transfected UBC. These cells exhibited apical-basolateral polarization and expression of the water channel aquaporin-2. These findings indicate that soluble HB-EGF and proHB-EGF induce branching tubulogenesis in UBC in different ways. Juxtacrine activation by proHB-EGF or the synergic action of soluble HB-EGF with transforming growth factor-β is important for well balanced morphogenesis of the collecting duct system.

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