scholarly journals Growth factors stimulate the Na-K-2Cl cotransporter NKCC1 through a novel Cl−-dependent mechanism

2001 ◽  
Vol 281 (6) ◽  
pp. C1948-C1953 ◽  
Author(s):  
Gengru Jiang ◽  
Janet D. Klein ◽  
W. Charles O'Neill
Keyword(s):  
Growth Factors ◽  
Cell Volume ◽  
Lysophosphatidic Acid ◽  
Myosin Light Chain ◽  
Fibroblast Growth ◽  
Volume Increase ◽  
Aortic Endothelial Cells ◽  
Cytoskeletal Regulation ◽  
Dependent Mechanism ◽  
Stimulation Of

The Na-K-2Cl cotransporter NKCC1 is an important volume-regulatory transporter that is regulated by cell volume and intracellular Cl−. This regulation appears to be mediated by phosphorylation of NKCC1, although there is evidence for additional, cytoskeletal regulation via myosin light chain (MLC) kinase. NKCC1 is also activated by growth factors and may contribute to cell hypertrophy, but the mechanism is unknown. In aortic endothelial cells, NKCC1 (measured as bumetanide-sensitive86Rb+ influx) was rapidly stimulated by serum, lysophosphatidic acid, and fibroblast growth factor, with the greatest stimulation by serum. Serum increased bumetanide-sensitive influx significantly more than bumetanide-sensitive efflux (131% vs. 44%), indicating asymmetric stimulation of NKCC1, and produced a 17% increase in cell volume and a 25% increase in Cl− content over 15 min. Stimulation by serum and hypertonic shrinkage were additive, and serum did not increase phosphorylation of NKCC1 or MLC, and did not decrease cellular Cl− content. When cellular Cl− was replaced with methanesulfonate, influx via NKCC1 increased and was no longer stimulated by serum, whereas stimulation by hypertonic shrinkage still occurred. Based on these results, we propose a novel mechanism whereby serum activates NKCC1 by reducing its sensitivity to inhibition by intracellular Cl−. This resetting of the Cl− set point of the transporter enables the cotransporter to produce a hypertrophic volume increase.

scholarly journals Bovine brain and pituitary fibroblast growth factors: comparison of their abilities to support the proliferation of human and bovine vascular endothelial cells.

1983 ◽  
Vol 97 (6) ◽  
pp. 1677-1685 ◽  
Author(s):  
D Gospodarowicz ◽  
J Cheng ◽  
M Lirette
Keyword(s):  
Endothelial Cells ◽  
Growth Factors ◽  
Cell Cultures ◽  
Vascular Endothelial Cells ◽  
Fibroblast Growth Factors ◽  
Low Density ◽  
Vascular Endothelial ◽  
Fibroblast Growth ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells

The mitogenic effects of brain and pituitary fibroblast growth factors (FGF) on vascular endothelial cells derived from either human umbilical vein or bovine aortic arch have been compared. Both brain and pituitary FGF are mitogenic for low density human umbilical endothelial (HUE) cell cultures maintained on either fibronectin- or laminin-coated dishes or on biomatrices produced by cultured cells such as bovine corneal endothelial cells or the teratocarcinoma cell line PF-HR-9. Pituitary FGF triggered the proliferation of HUE cells at concentrations as low as 0.25 ng/ml, with a half-maximal response at 0.55 ng/ml and optimal effect at 2.5 to 5 ng/ml. It was 50,000-fold more potent than commercial preparations of endothelial cell growth factor and 40 times more potent than commercial preparations of pituitary FGF. Similar results were observed when the effect of pituitary FGF was tested on low density cultures of adult bovine aortic endothelial cells. When the activity of brain and pituitary FGF on low density HUE cell cultures was compared, both mitogens were active. To confirm the presence in brain extract of both acidic and neutral, as well as of basic mitogen, for HUE cells, brain tissues were extracted at acidic (4.5), neutral (7.2), and basic (8.5) pH. The three types of extracts were equally potent in supporting the proliferation of either HUE or adult bovine aortic endothelial cells. When the various extracts were absorbed at pH 6.0 on a carboxymethyl Sephadex C-50 column, the neutral and basic extracts had an activity after adsorption similar to that of unadsorbed extracts. In contrast, extracts prepared at pH 4.5 lost 90-95% of their activity which was recovered in the adsorbed fraction containing FGF.

scholarly journals Tyrosine 766 in the fibroblast growth factor receptor-1 is required for FGF-stimulation of phospholipase C, phospholipase D, phospholipase A(2), phosphoinositide 3-kinase and cytoskeletal reorganisation in porcine aortic endothelial cells

2000 ◽  
Vol 113 (4) ◽  
pp. 643-651 ◽  
Author(s):  
M.J. Cross ◽  
M.N. Hodgkin ◽  
S. Roberts ◽  
E. Landgren ◽  
M.J. Wakelam ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Fibroblast Growth Factor Receptor ◽  
Growth Factor Receptor ◽  
Fibroblast Growth ◽  
Wild Type ◽  
Aortic Endothelial Cells ◽  
Phosphoinositide 3 Kinase ◽  
Porcine Aortic Endothelial Cells ◽  
Stimulation Of

Fibroblast growth factor-mediated signalling was studied in porcine aortic endothelial cells expressing either wild-type fibroblast growth factor receptor-1 or a mutant receptor (Y766F) unable to bind phospholipase C-(γ). Stimulation of cells expressing the wild-type receptor resulted in activation of phospholipases C, D and A(2) and increased phosphoinositide 3-kinase activity. Stimulation of the wild-type receptor also resulted in stress fibre formation and a cellular shape change. Cells expressing the Y766F mutant receptor failed to stimulate phospholipase C, D and A(2) as well as phosphoinositide 3-kinase. Furthermore, no stress fibre formation or shape change was observed. Both the wild-type and Y766F receptor mutant activated MAP kinase and elicited proliferative responses in the porcine aortic endothelial cells. Thus, fibroblast growth factor receptor-1 mediated activation of phospholipases C, D and A(2) and phosphoinositide 3-kinase was dependent on tyrosine 766. Furthermore, whilst tyrosine 766 was not required for a proliferative response, it was required for fibroblast growth factor receptor-1 mediated cytoskeletal reorganisation.

Stimulation of polyphosphoinositide hydrolysis in Swiss 3T3 cells by recombinant fibroblast growth factors

FEBS Letters ◽  
1989 ◽  
Vol 247 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Kenneth D. Brown ◽  
Diana M. Blakeley ◽  
David R. Brigstock
Keyword(s):  
Growth Factors ◽  
Fibroblast Growth Factors ◽  
Fibroblast Growth ◽  
3T3 Cells ◽  
Swiss 3T3 ◽  
Stimulation Of

The stimulation of Na,K,Cl cotransport and of system A for neutral amino acid transport is a mechanism for cell volume increase during the cell cycle

1996 ◽  
Vol 10 (8) ◽  
pp. 920-926 ◽  
Author(s):  
Ovidio Bussolati ◽  
Jacopo Uggeri ◽  
Silvana Belletti ◽  
Valeria Dall'Asta ◽  
Gian C. Gazzola
Keyword(s):  
Cell Cycle ◽  
Amino Acid ◽  
Cell Volume ◽  
Amino Acid Transport ◽  
Neutral Amino Acid ◽  
Acid Transport ◽  
Volume Increase ◽  
System A ◽  
Stimulation Of

Effects of apical membrane Cl(-)-formate exchange on cell volume in rabbit proximal tubule

1990 ◽  
Vol 258 (3) ◽  
pp. F530-F536 ◽  
Author(s):  
L. Schild ◽  
P. S. Aronson ◽  
G. Giebisch
Keyword(s):  
Proximal Tubule ◽  
Cell Volume ◽  
Apical Membrane ◽  
Cell Swelling ◽  
Volume Changes ◽  
Proximal Tubule Cells ◽  
Volume Increase ◽  
Tubule Lumen ◽  
Stimulation Of

We used real-time recordings of cell volume changes to test for the role of the Cl(-)-formate exchanger in mediating NaCl entry across the apical membrane of rabbit proximal tubule cells. In the absence of extracellular Cl-, 0.5 and 5 mM formate in the tubule lumen induced an increase in cell volume of 1 and 9%, respectively. Formate-induced cell swelling was reduced by alkalinizing the tubule lumen or by addition of luminal amiloride (2 mM), indicating that the increase in cell volume results from the intracellular accumulation of Na-formate via nonionic diffusion of formic acid in parallel with Na(+)-H+ exchange. The cell volume increase induced by 0.5 mM formate was potentiated (from 1 to 4%) by Cl-, as expected for a formate-mediated stimulation of NaCl uptake via parallel Cl(-)-formate exchange and Na(+)-H+ exchange across the apical membrane. By contrast, the cell volume increase induced by 5 mM formate was attenuated (from 9 to 4%) by Cl-. The attenuating effect of Cl- on formate-induced cell swelling required the operation of the apical membrane Cl(-)-formate exchanger. The effect of 1:1 Cl(-)-formate exchange to attenuate formate-induced cell swelling can be explained if the cell possesses a volume-activated anion exit pathway, most likely at the basolateral cell membrane, that is capable of mediating the efflux of Cl- but not formate from the cell.

Functional coupling of Na(+)-K(+)-2Cl- cotransport and Ca(2+)-dependent K+ channels in vascular endothelial cells

1995 ◽  
Vol 269 (1) ◽  
pp. C267-C274 ◽  
Author(s):  
W. C. O'Neill ◽  
D. F. Steinberg
Keyword(s):  
Endothelial Cells ◽  
Cell Volume ◽  
Vascular Endothelial Cells ◽  
K Channel ◽  
Functional Coupling ◽  
Channel Blockers ◽  
Vascular Endothelial ◽  
Aortic Endothelial Cells ◽  
K Channels ◽  
Stimulation Of

To determine whether the activation of Na(+)-K(+)-2Cl- cotransport by Ca(2+)-mobilizing agonists is a direct effect of Ca2+ or is secondary to activation of Ca(2+)-dependent K+ channels [via cell shrinkage or decreased intracellular Cl- concentration ([Cl-]), we measured K+ fluxes in aortic endothelial cells in response to ATP and bradykinin. With either agonist there was an immediate bumetanide-insensitive efflux inhibitable by the K+ channel blockers tetrabutylammonium (TBA, 23 mM) and quinidine (1 mM), followed several minutes later by increased bumetanide-sensitive efflux or influx (Na(+)-K(+)-2Cl- cotransport). ATP induced a loss of cell K+ that was prevented by TBA and augmented by bumetanide. Both TBA and quinidine prevented the stimulation of cotransport by agonists but not by hypertonic shrinkage. Raising medium [K+] to prevent K+ loss also blocked activation of cotransport by agonists. The results indicate that the stimulation of Na(+)-K(+)-2Cl- cotransport by Ca2+ is not direct but instead is indirect via activation of Ca(2+)-dependent K+ channels and a resulting decrease in cell volume and intracellular [Cl-]. This suggests that at least one role of Na(+)-K(+)-2Cl- cotransport in endothelial cells is to maintain cell volume and intracellular [Cl-] during agonist stimulation.

0-93. Autocrine and paracrine stimulation of breast cancer by fibroblast growth factors

The Breast ◽  
1997 ◽  
Vol 6 (4) ◽  
pp. 250-251
Author(s):  
S. Marsh ◽  
C. Johnston ◽  
J. Gomm ◽  
C. Zammit ◽  
H. Sinnett ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Growth Factors ◽  
Fibroblast Growth Factors ◽  
Fibroblast Growth ◽  
Stimulation Of

Regulation of vascular endothelial cell volume by Na-K-2Cl cotransport

1992 ◽  
Vol 262 (2) ◽  
pp. C436-C444 ◽  
Author(s):  
W. C. O'Neill ◽  
J. D. Klein
Keyword(s):  
Endothelial Cells ◽  
Cell Volume ◽  
Vascular Endothelial Cell ◽  
Cell Swelling ◽  
Hypertonic Medium ◽  
Aortic Endothelial Cells ◽  
Endothelial Integrity ◽  
Stimulation Of ◽  
In Cells ◽  
Aortic Endothelial

The relationship between cell volume and Na-K-2Cl cotransport was studied in cultured bovine aortic endothelial cells. Hypertonic cell shrinkage increased bumetanide-sensitive, Na- or Cl-dependent K influx without altering bumetanide-insensitive influx. Greater stimulation of cotransport was observed in cells shrunken isosmotically either by preincubation in K-free and Na-free medium or by preincubation in hypotonic medium. Cell swelling, produced by preincubation in isotonic high-K medium, inhibited bumetanide-sensitive K influx. Simultaneous measurements of [3H]bumetanide binding and K influx revealed an increased number of binding sites without an increased influx per binding site in shrunken cells. Bumetanide did not alter the volume or ion content of cells in isotonic or hypertonic medium, indicating that no net influx of ions occurs through cotransport under these conditions. In isosmotically shrunken cells, there was greater stimulation of bumetanide-sensitive influx than of bumetanide-sensitive efflux, resulting in net bumetanide-sensitive influx. Rapid recovery of cell K, Na, and water occurred over 10-20 min and was inhibited by bumetanide or by the removal of external Na or Cl. These data demonstrate that Na-K-2Cl cotransport in aortic endothelial cells is regulated by cell volume, possibly through changes in the number of functional cotransporters, and mediates a brisk regulatory volume increase in isosmotically shrunken cells. Although thermodynamically favored, no net influx occurs through Na-K-2Cl cotransport in cells of normal volume or in hypertonically shrunken cells. This suggests additional regulation of cotransport, perhaps through trans-inhibition by intracellular Cl. Regulation of cell volume by Na-K-2Cl cotransport may be important in maintaining endothelial integrity.

Astrocytes from Na+-K+-Cl−cotransporter-null mice exhibit absence of swelling and decrease in EAA release

2002 ◽  
Vol 282 (5) ◽  
pp. C1147-C1160 ◽  
Author(s):  
Gui Su ◽  
Douglas B. Kintner ◽  
Michael Flagella ◽  
Gary E. Shull ◽  
Dandan Sun
Keyword(s):  
Cell Volume ◽  
Glutamate Release ◽  
Volume Increase ◽  
Regulatory Volume Increase ◽  
A Value ◽  
Cortical Astrocytes ◽  
High K ◽  
Stimulation Of

We reported previously that inhibition of Na+-K+-Cl− cotransporter isoform 1 (NKCC1) by bumetanide abolishes high extracellular K+concentration ([K+]o)-induced swelling and intracellular Cl− accumulation in rat cortical astrocytes. In this report, we extended our study by using cortical astrocytes from NKCC1-deficient (NKCC1−/−) mice. NKCC1 protein and activity were absent in NKCC1−/− astrocytes. [K+]o of 75 mM increased NKCC1 activity approximately fourfold in NKCC1+/+ cells ( P< 0.05) but had no effect in NKCC1−/− astrocytes. Intracellular Cl− was increased by 70% in NKCC1+/+ astrocytes under 75 mM [K+]o ( P < 0.05) but remained unchanged in NKCC1−/− astrocytes. Baseline intracellular Na+ concentration ([Na+]i) in NKCC1+/+ astrocytes was 19.0 ± 0.5 mM, compared with 16.9 ± 0.3 mM [Na+]i in NKCC1−/− astrocytes ( P < 0.05). Relative cell volume of NKCC1+/+ astrocytes increased by 13 ± 2% in 75 mM [K+]o, compared with a value of 1.0 ± 0.5% in NKCC1−/− astrocytes ( P < 0.05). Regulatory volume increase after hypertonic shrinkage was completely impaired in NKCC1−/− astrocytes. High-[K+]o-induced 14C-labeledd-aspartate release was reduced by ∼30% in NKCC1−/− astrocytes. Our study suggests that stimulation of NKCC1 is required for high-[K+]o-induced swelling, which contributes to glutamate release from astrocytes under high [K+]o.

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