Molecular Mechanisms by Which Iron Induces Nitric Oxide Synthesis in Cultured Proximal Tubule Cells

2001 ◽  
Vol 9 (3) ◽  
pp. 198-204 ◽  
Author(s):  
Liguang Chen ◽  
Yiping Wang ◽  
Lukas K. Kairaitis ◽  
Yang Wang ◽  
Bao-Hong Zhang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Proximal Tubule ◽  
Molecular Mechanisms ◽  
Nitric Oxide Synthesis ◽  
Proximal Tubule Cells ◽  
Tubule Cells

Abstract P169: Antenatal Betamethasone Attenuates the Angiotensin-(1-7)/Nitric Oxide Axis in Adult Male but not Female Renal Proximal Tubule Cells

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Yixin Su ◽  
Victor M Pulgar ◽  
Jianli Bi ◽  
Mark Chappell ◽  
James C Rose
Keyword(s):  
Nitric Oxide ◽  
Proximal Tubule ◽  
Adult Male ◽  
Fetal Programming ◽  
Cell Model ◽  
Specific Effect ◽  
Proximal Tubules ◽  
Proximal Tubule Cells ◽  
Tubule Cells ◽  
Na Uptake

Our studies have revealed a sex-specific effect of fetal programming on sodium (Na+) excretion in adult sheep whereby the males exhibit reduced Na+ excretion and an attenuated natriuretic response to Ang-(1-7) as compared to the females. We hypothesize that the renal proximal tubules are a key target for the early programming effects of glucocorticoids exposure to regulate Na+ handling in the adult males. Therefore, we isolated and cultured cortical proximal tubule cells (RPTC) from adult male and female sheep antenatally exposed to betamethasone (Beta) or vehicle. Na+ uptake and nitric oxide (NO) were assessed with Sodium Green and DAF fluorescence prior to and following a low dose of Ang-(1-7) (1x10-11 M) in isolated RPTC from sheep at ~1.5 years of age. Data are expressed as % of basal uptake or area under the curve (AUC) for Na+ or % of control for NO. Male Beta RPTC exhibit greater Na+ uptake than male vehicle cells (427±32%, n=13, vs. 315±28%, n=14, p<0.05; however, Beta had no effect on Na+ uptake in the female cells (242±18%, n=9, vs. 250±15%, n=10, p>0.05). Ang-(1-7) inhibited Na+ uptake in RPTC from vehicle male (255±40%) and from both vehicle (191±14%) and Beta (209±11%) females (Figure 1B), but failed to attenuate Na+ uptake in Beta male cells (Figure 1A). Beta exposure also abolished NO stimulation by Ang-(1-7) in male but not female RPTC (Figure 1C). We conclude that an Ang-(1-7)-NO-dependent pathway contributes to the sex-dependent consequences of programming on Na+ regulation in the proximal tubules of the kidney. Moreover, the RPTC retain both the sex and Beta-induced phenotype of the adult and may reflect an appropriate cell model of fetal programming.

scholarly journals Antenatal betamethasone attenuates the angiotensin-(1–7)-Mas receptor-nitric oxide axis in isolated proximal tubule cells

2017 ◽  
Vol 312 (6) ◽  
pp. F1056-F1062 ◽  
Author(s):  
Yixin Su ◽  
Jianli Bi ◽  
Victor M. Pulgar ◽  
Mark C. Chappell ◽  
James C. Rose
Keyword(s):  
Nitric Oxide ◽  
Proximal Tubule ◽  
Cell Model ◽  
Primary Cultures ◽  
Specific Effect ◽  
Renal Tubules ◽  
Proximal Tubule Cells ◽  
Mas Receptor ◽  
Tubule Cells

We previously reported a sex-specific effect of antenatal treatment with betamethasone (Beta) on sodium (Na+) excretion in adult sheep whereby treated males but not females had an attenuated natriuretic response to angiotensin-(1–7) [Ang-(1–7)]. The present study determined the Na+ uptake and nitric oxide (NO) response to low-dose Ang-(1–7) (1 pM) in renal proximal tubule cells (RPTC) from adult male and female sheep antenatally exposed to Beta or vehicle. Data were expressed as percentage of basal uptake or area under the curve for Na+ or percentage of control for NO. Male Beta RPTC exhibited greater Na+ uptake than male vehicle cells (433 ± 28 vs. 330 ± 26%; P < 0.05); however, Beta exposure had no effect on Na+ uptake in the female cells (255 ± 16 vs. 255 ± 14%; P > 0.05). Ang-(1–7) significantly inhibited Na+ uptake in RPTC from vehicle male (214 ± 11%) and from both vehicle (190 ± 14%) and Beta (209 ± 11%) females but failed to attenuate Na+ uptake in Beta male cells. Beta exposure also abolished stimulation of NO by Ang-(1–7) in male but not female RPTC. Both the Na+ and NO responses to Ang-(1–7) were blocked by Mas receptor antagonist d-Ala7-Ang-(1–7). We conclude that the tubular Ang-(1–7)-Mas-NO pathway is attenuated in males and not females by antenatal Beta exposure. Moreover, since primary cultures of RPTC retain both the sex and Beta-induced phenotype of the adult kidney in vivo they appear to be an appropriate cell model to examine the effects of fetal programming on Na+ handling by the renal tubules.

scholarly journals FoxM1 drives proximal tubule proliferation during repair from acute kidney injury

2018 ◽  
Author(s):  
Monica Chang-Panesso ◽  
Farid F. Kadyrov ◽  
Matthew Lalli ◽  
Haojia Wu ◽  
Shiyo Ikeda ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Molecular Mechanisms ◽  
Growth Factor Receptor ◽  
Kidney Injury ◽  
Acute Injury ◽  
Genetic Lineage ◽  
Proximal Tubule Cells ◽  
Epidermal Growth ◽  
Tubule Cells ◽  
Injury And Repair

AbstractThe proximal tubule has a remarkable capacity for repair after acute injury but the cellular lineage and molecular mechanisms underlying this repair response have been poorly characterized. Here, we developed a Kim-1-GFPCreERt2knockin mouse line (Kim-1-GCE), performed genetic lineage analysis after injury and measured the cellular transcriptome of proximal tubule during repair. Acutely injured genetically labeled clones co-expressed Kim-1, Vimentin, Sox9 and Ki67, indicating a dedifferentiated and proliferative state. Clonal analysis revealed clonal expansion of Kim-1+ cells, indicating that acutely injured, dedifferentiated proximal tubule cells account for repair rather than a fixed tubular progenitor. Translational profiling during injury and repair revealed signatures of both successful and unsuccessful maladaptive repair. The transcription factor FoxM1 was induced early in injury, was required for epithelial proliferation, and was dependent on epidermal growth factor receptor (EGFR) stimulation. In conclusion, dedifferentiated proximal tubule cells effect proximal tubule repair and we reveal a novel EGFR-FoxM1-dependent signaling pathway that drives proliferative repair after injury.

scholarly journals Involvement of Endogenous Nitric Oxide in the Regulation of K+ Channel Activity in Cultured Human Proximal Tubule Cells

2006 ◽  
Vol 56 (6) ◽  
pp. 407-413 ◽  
Author(s):  
Kazuyoshi Nakamura ◽  
Wataru Habano ◽  
Toshiyuki Kojo ◽  
You Komagiri ◽  
Takahiro Kubota ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Proximal Tubule ◽  
K Channel ◽  
Channel Activity ◽  
Proximal Tubule Cells ◽  
Endogenous Nitric Oxide ◽  
Tubule Cells ◽  
Human Proximal Tubule

Nitric oxide stimulates guanylate cyclase and regulates sodium transport in rabbit proximal tubule

1996 ◽  
Vol 270 (1) ◽  
pp. F106-F115 ◽  
Author(s):  
A. Roczniak ◽  
K. D. Burns
Keyword(s):  
Nitric Oxide ◽  
Proximal Tubule ◽  
Guanylate Cyclase ◽  
Soluble Guanylate Cyclase ◽  
Inhibitory Effect ◽  
Na Transport ◽  
Uptake Inhibition ◽  
Proximal Tubule Cells ◽  
Cyclic Monophosphate ◽  
Tubule Cells

The proximal tubule contains the target for nitric oxide (NO), soluble guanylate cyclase, and has the capacity for NO production. Inhibition of renal NO synthesis reduces fractional excretion of lithium, suggesting an inhibitory effect of NO on proximal tubule Na+ transport. The present studies determined direct effects of donors of NO in rabbit proximal tubule. In both freshly isolated proximal tubule segments and in primary cultures of proximal tubule cells, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP) caused dose-dependent increases in guanosine 3',5'-cyclic monophosphate (cGMP). SNAP was more potent than SNP in stimulating cGMP; this was associated with an enhanced production of nitrite, the stable end-product of NO. In rabbit proximal tubule cells, SNP or SNAP (10(-3) M) significantly inhibited the activity of the apical Na+/H+ exchanger, determined by assay of amiloride-sensitive 22Na+ uptake (% inhibition: SNP, 34.90 +/- 5.52%, P < 0.001; SNAP, 30.77 +/- 8.20%, P < 0.002). To determine the role of cGMP in mediating these effects, proximal tubule cells were incubated with the membrane-permeable analogue, 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP). Na+/H+ exchange was significantly inhibited by 8-BrcGMP (10(3)M) (% inhibition: 32.40 +/- 9.06%: P < 0.05). The inhibitor of soluble guanylate cyclase, LY-83583, caused partial inhibition of SNP-stimulated cGMP generation and partly blocked the inhibitory effect of SNP on Na+/H+ exchange. Protein kinase A (PKA) activity was not stimulated by SNP, indicating that potential cross-activation of PKA by cGMP did not mediate the effects of NO donors. These data indicate that NO stimulates soluble guanylate cyclase in rabbit proximal tubule and causes inhibition of Na-/H+ exchange. This is at least partly mediated by generation of cGMP. We conclude that NO is an important autocrine or paracrine factor directly regulating Na+ transport in the proximal tubule.

scholarly journals Hnf4a is required for the development of Cdh6-expressing progenitors into proximal tubules in the mouse kidney

2020 ◽  
Author(s):  
Sierra S. Marable ◽  
Eunah Chung ◽  
Joo-Seop Park
Keyword(s):  
Proximal Tubule ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Mouse Kidney ◽  
Proximal Tubules ◽  
Transmembrane Transport ◽  
Proximal Tubule Cells ◽  
Expression Of Genes ◽  
Genomic Analyses ◽  
Tubule Cells

ABSTRACTBackgroundHnf4a is a major regulator of renal proximal tubule (PT) development. In humans, a mutation in HNF4A is associated with Fanconi renotubular syndrome (FRTS), which is caused by defective PT functions. In mice, mosaic deletion of Hnf4a in the developing kidney causes a paucity of PT cells, leading to FRTS-like symptoms. The molecular mechanisms underlying the role of Hnf4a in PT development remain unclear.MethodsWe generated a new Hnf4a mutant mouse model employing Osr2Cre, which effectively deletes Hnf4a in developing nephrons. We characterized the mutant phenotype by immunofluorescence analysis. We performed lineage analysis to test if Cdh6-expressing cells are PT progenitors. We also performed genome-wide mapping of Hnf4a binding sites and differential gene analysis of Hnf4a mutant kidneys to identify direct target genes of Hnf4a.ResultsDeletion of Hnf4a with Osr2Cre led to the complete loss of mature PT cells, causing lethality in the Hnf4a mutant mice. We found that Cdh6high, LTLlow cells serve as PT progenitors and that they show higher proliferation than Cdh6low, LTLhigh differentiated PT cells. We also found that Hnf4a is required for PT progenitors to develop into differentiated PT cells. Our genomic analyses revealed that Hnf4a directly regulates the expression of genes involved in transmembrane transport and metabolism.ConclusionsOur findings show that Hnf4a promotes the development of PT progenitors into differentiated PT cells by regulating the expression of genes associated with reabsorption, the major function of PT cells.SignificanceProximal tubule cells are the most abundant cell type in the mammalian kidney and they perform the bulk of the renal reabsorption function. Despite their importance in kidney function, the molecular mechanisms of proximal tubule development and maturation are not well understood. Here we find that, in the developing mouse kidney, Cdh6high, LTLlow cells act as proximal tubule progenitors and that Hnf4a is required for these cells to further develop into proximal tubules. Our genomic analyses show that Hnf4a directly regulate the expression of genes required for reabsorption such as transmembrane transport genes and metabolism genes. This study advances our understanding of how kidney proximal tubule cells form during development.

Evidence suggesting that nitric oxide mediates iron-induced toxicity in cultured proximal tubule cells

1998 ◽  
Vol 274 (1) ◽  
pp. F18-F25 ◽  
Author(s):  
Liguang Chen ◽  
Bao-Hong Zhang ◽  
David C. H. Harris
Keyword(s):  
Nitric Oxide ◽  
Lipid Peroxidation ◽  
Proximal Tubule ◽  
Cell Damage ◽  
No Production ◽  
Dependent Manner ◽  
No Donor ◽  
Variable Effect ◽  
Proximal Tubule Cells ◽  
Tubule Cells

The potential role of nitric oxide (NO) in iron-induced toxicity was studied in proximal tubule cells in primary culture. NO production ([Formula: see text]/[Formula: see text]) was significantly increased in iron-treated compared with control cells (3.43 ± 0.08 vs. 1.56 ± 0.08 nmol/dish, P < 0.01). NO synthase (NOS) activity was also induced by iron treatment (16.2 ± 2.0 vs. 0.4 ± 0.2 nmol of [Formula: see text]citrulline/mg protein, P < 0.01).l-Arginine, a substrate for NOS, augmented iron-induced NO production and cell damage [lactate dehydrogenase (LDH) leakage], whereas aminoguanidine, an inhibitor of NOS, reduced iron-induced NO production and LDH leakage. Sodium nitroprusside, an exogenous NO donor, induced LDH leakage in a dose-dependent manner, but no effect on lipid peroxidation {malondialdehyde bis[dimethyl acetal] (MDA) production} was observed. Superoxide dismutase and catalase decreased iron-induced MDA production but did not affect LDH leakage or NO production. Dimethylpyrroline N-oxide and desferal prevented MDA production, LDH leakage, and NO production. We concluded that NO is one of the mediators of iron-induced toxicity in proximal tubule cells. NO-induced toxicity is not dependent on lipid peroxidation. This may explain the variable effect of different antioxidants on cell damage and lipid peroxidation in iron-induced cytotoxicity.

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