A comparative study on the uptake of α-aminoisobutyric acid by normal and immortalized human embryonic kidney cells from proximal tubule

Jessen, Henrik; Røigaard, Hans; Riahi-Esfahani, Sam; Jacobsen, Christian

doi:10.1016/0005-2736(94)90085-x

Cited by 22 publications

(13 citation statements)

References 26 publications

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“…The human kidney epithelial cell line IHKE [25][26][27] was maintained in DMEM/Ham's-F12, 1% fetal calf serum, penicillin (100 U/mL), streptomycin (100 ng/ mL), and l-glutamine (2 mmol/mL), insulin-transferrin-sodium selenite media supplement (10 μL/mL), NaHCO 3 (1.25 μg/mL), sodium pyruvate (55 μg/mL), epidermal growth factor (10 μg/L; all Sigma-Aldrich,) and HEPES (15 μmol/mL, Merck, Darmstadt, Germany). Human primary aortic ECs (PromoCell, Heidelberg, Germany) were maintained in endothelial cell growth medium MV with 10% fetal calf serum, epidermal growth factor (10 ng/mL), and hydrocortisone (1 μg/mL; all PromoCell).…”

Section: Cell Culturementioning

confidence: 99%

“…EA.hy926 cells have been used commonly to investigate changes in endothelial function, [11][12][13] whereas IHKE cells have been introduced to study the function of renal Ca 2+ -, Na + -, and K + -channels. [25][26][27] We identified sAC protein in whole cell extract and, particularly, in the nucleus of EA.hy926 and IHKE cells (Figure 1), with 3 protein isoforms designated A (≈55 kDa), B (≈65 kDa), and C (≈80 kDa). The nuclear accumulation of all 3 detected isoforms in ECs was increased by cAMP stimulation.…”

Section: Cellular Sac Localizationmentioning

confidence: 99%

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Soluble Adenylyl Cyclase in Vascular Endothelium

et al. 2014

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Section: Cell Culturementioning

confidence: 99%

Section: Cellular Sac Localizationmentioning

confidence: 99%

Soluble Adenylyl Cyclase in Vascular Endothelium

et al. 2014

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“…It has been shown before that IHKE-1 cells can transport AIB [5,6] and -alanine as well as taurine [4], indicating the existence of the A or imino as well as the system. Our data favor the existence of the imino system since AIB was added to the apical membrane and strongly depolarized the V m of IHKE-1 cells.…”

Section: Namentioning

confidence: 99%

“…In several uptake studies it was proven that these cells are able to transport neutral α-and -AA, taurine and -alanine as well as the non-metabolizable neutral α-aminoisobutyric acid (AIB) [4][5][6]. The aim of this study was to further characterize the different AA transport systems in these cells using the patch-clamp technique to monitor changes in membrane voltage (V m ).…”

Section: Introductionmentioning

confidence: 99%

Na+ -Dependent and -Independent Amino Acid Transport Systems in Immortalized Human Kidney Epithelial Cells Derived from the Proximal Tubule

Hirsch

Gonska

Waldegger

et al. 1998

Kidney Blood Press Res

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In the proximal tubule Na⁺-dependent (SDAT) and Na⁺-independent (SIAT) amino acid (AA) transporters are present. The effects of neutral, basic, and acidic AA on membrane voltage (V_m) of immortalized human kidney epithelial (IHKE-1) cells derived from the proximal tubule were examined using the slow whole-cell patch-clamp technique. In the presence of Na⁺ AA depolarized V_m in a concentration-dependent manner (0.05–5 mM) with Asp = Arg = Glu =2Cys < Pro = Leu < Phe = AIB = Ala = Pro = Asn < Gly. In the absence of extracellular Na⁺ a decreased depolarization was seen with most neutral AA (Ala, Pro, Asn, Gly, Phe, and Leu), and the depolarization was increased with Asp, Glu, Arg, and 2Cys (1 mM each). In the absence of Na⁺ and a reduction in Cl^– (5 mM) the depolarization by Arg was reduced. Unlike that predicted for transport by system b^0,+ which exchanges neutral against dibasic amino acids, Leu does not hyperpolarize but depolarize V_m of IHKE-1 cells in the absence of extracellular Na⁺. After removal of Na⁺ (0 mM) and a reduction in Cl^– (5 mM) in the extracellular solution, Leu or Glu hyperpolarized V_m, indicating that IHKE-1 cells possess two different SIAT systems, one Cl^–-independent and similar to system b^0,+ and one novel Cl^–-dependent system, which might be a Cl^–/AA exchanger and can be blocked by the Cl^–-channel blockers 5-nitro-2-(3-phenylpropylamino)-benzoate (10 μM) and 4,4′-diisothiocyanostibene-2,2′-disulfonic acid (50 μM). B system-related AA transporters might be responsible for the C^–-independent SIAT, since we were able to detect its signal by Northern blot analysis.

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“…Several studies on IHKE-1 cells have shown that these cells are typical proximal tubule cells. They express specific key enzymes (21), different Na ϩ -dependent and -independent amino acid transporters (22,23), and organic cation transporters (24) and they are able to regulate transport by natriuretic peptides (25) or to take up albumin (26). Here we present evidence for the existence of proximal tubule-specific Na ϩ /H ϩ -exchanger (NHE-3) and the Na ϩ -phosphate transporter (NaPi-IIa) in the apical membrane.…”

mentioning

confidence: 99%

Inhibition of Na+-Dependent Transporters in Cystine-Loaded Human Renal Cells

Çetinkaya¹,

Schlatter²,

Hirsch³

et al. 2002

Journal of the American Society of Nephrology

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Abstract. Cystinosis is the most common cause of the renal Fanconi syndrome in children, leading to severe electrolyte disturbances and growth failure. A defective lysosomal transporter, cystinosin, results in intralysosomal accumulation of cystine. Loading cells with cystine dimethyl ester (CDME) is the only available model for this disease. This model was used to present electrophysiologic studies on immortalized human kidney epithelial (IHKE-1) cells that had been derived from the proximal tubule with the slow whole-cell patch clamp technique. Basal membrane voltages (V m ) of IHKE-1 cells were Ϫ30.7 Ϯ 0.4 mV (n ϭ 151). CDME concentration-dependently altered V m with an initial depolarization (2.7 Ϯ 0.2 mV; n ϭ 76; 1 mM CDME) followed by a more pronounced hyperpolarization (Ϫ9.9 Ϯ 1.0 mV; n ϭ 49). Three Na ϩ -dependent transporters were examined. Alanine (1 mM) depolarized IHKE-1 cells by 17.6 Ϯ 0.7 mV (n ϭ 59), and phosphate (1.8 mM) depolarized by 9.7 Ϯ 1.1 mV (n ϭ 18).Acidification of IHKE-1 cells with propionate (20 mM) resulted in a depolarization of V m by 7.1 Ϯ 0.3 mV (n ϭ 21) followed by a repolarization by 2.9 Ϯ 0.3 mV/min (n ϭ 17), reflecting Na ϩ /H ϩ -exchanger activity. Acute addition of 1 mM CDME did not alter the alanine-and propionate-induced changes in V m , but it reduced the phosphate-induced depolarization by 37 Ϯ 9% (n ϭ 10). Incubation with 1 mM CDME reduced the activity of all three transporters. Depolarizations by alanine and phosphate and the repolarization after propionate were inhibited by 57 Ϯ 4% (n ϭ 30), 45 Ϯ 9% (n ϭ 9), and 78 Ϯ 15% (n ϭ 8), respectively. In conclusion, this study demonstrates that CDME acutely alters V m of IHKE-1 cells and that at least three Na ϩ -dependent transporters are inhibited, the Na ϩ -phosphate cotransporter most sensitively. This might suggest that phosphate depletion and dissipation of the Na ϩ -gradient are involved in the development of the Fanconi syndrome of cystinosis.

show abstract

A comparative study on the uptake of α-aminoisobutyric acid by normal and immortalized human embryonic kidney cells from proximal tubule

Cited by 22 publications

References 26 publications

Soluble Adenylyl Cyclase in Vascular Endothelium

Soluble Adenylyl Cyclase in Vascular Endothelium

Na+ -Dependent and -Independent Amino Acid Transport Systems in Immortalized Human Kidney Epithelial Cells Derived from the Proximal Tubule

Inhibition of Na+-Dependent Transporters in Cystine-Loaded Human Renal Cells

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