scholarly journals Regulation of natriuretic peptide receptor-A gene expression and stimulation of its guanylate cyclase activity by transcription factor Ets-1

2009 ◽  
Vol 29 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Prerna Kumar ◽  
Gevoni Bolden ◽  
Kiran K. Arise ◽  
Stephen T. Krazit ◽  
Kailash N. Pandey
Keyword(s):  
Natriuretic Peptide ◽  
Gene Transcription ◽  
Guanylate Cyclase ◽  
Promoter Activity ◽  
Target Cells ◽  
Mrna Levels ◽  
Natriuretic Peptide Receptor ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A ◽  
Npr1 Gene

ANP (atrial natriuretic peptide) exerts its biological effects by binding to GC (guanylate cyclase)-A/NPR (natriuretic peptide receptor)-A, which generates the second messenger cGMP. The molecular mechanism mediating Npr1 (coding for GC-A/NPRA) gene regulation and expression is not well understood. The objective of the present study was to elucidate the mechanism by which Ets-1 [Ets (E twenty-six) transformation-specific sequence] contributes to the regulation of Npr1 gene transcription and expression. Chromatin immunoprecipitation and gel-shift assays confirmed the in vivo and in vitro binding of Ets-1 to the Npr1 promoter. Overexpression of Ets-1 enhanced significantly Npr1 mRNA levels, protein expression, GC activity and ANP-stimulated intracellular accumulation of cGMP in transfected cells. Depletion of endogenous Ets-1 by siRNA (small interfering RNA) dramatically decreased promoter activity by 80%. Moreover, methylation of the Npr1 promoter region (−356 to +55) reduced significantly the promoter activity and hypermethylation around the Ets-1 binding sites directly reduced Ets-1 binding to the Npr1 promoter. Collectively, the present study demonstrates that Npr1 gene transcription and GC activity of the receptor are critically controlled by Ets-1 in target cells.

scholarly journals ANP-mediated inhibition of distal nephron fractional sodium reabsorption in wild-type and mice overexpressing natriuretic peptide receptor

2010 ◽  
Vol 298 (1) ◽  
pp. F103-F108 ◽  
Author(s):  
Di Zhao ◽  
Kailash N. Pandey ◽  
L. Gabriel Navar
Keyword(s):  
Natriuretic Peptide ◽  
Sodium Excretion ◽  
Urinary Sodium Excretion ◽  
Sodium Reabsorption ◽  
Natriuretic Peptide Receptor ◽  
Distal Nephron ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A ◽  
Npr1 Gene

Atrial natriuretic peptide (ANP) elicits natriuresis; however, the relative contributions of proximal and distal nephron segments to the overall ANP-induced natriuresis have remained uncertain. This study was performed to characterize the effects of ANP on distal nephron sodium reabsorption determined after blockade of the two major distal nephron sodium transporters with amiloride (5 μg/g body wt) plus bendroflumethiazide (12 μg/g body wt) in male anesthetized C57/BL6 and natriuretic peptide receptor-A gene (Npr1) targeted four-copy mice. The lower dose of ANP (0.1 ng·g body wt−1·min−1, n = 6) increased distal sodium delivery (DSD, 2.4 ± 0.4 vs. 1.6 ± 0.2 μeq/min, P < 0.05) but did not change fractional reabsorption of DSD compared with control (86.3 ± 2.0 vs. 83.9 ± 3.6%, P > 0.05), thus limiting the magnitude of the natriuresis. In contrast, the higher dose (0.2 ng·g body wt−1·min−1, n = 6) increased DSD (2.8 ± 0.3 μeq/min, P < 0.01) and also decreased fractional reabsorption of DSD (67.4 ± 4.5%, P < 0.01), which markedly augmented the natriuresis. In Npr1 gene-duplicated four-copy mice ( n = 6), the lower dose of ANP increased urinary sodium excretion (0.6 ± 0.1 vs. 0.3 ± 0.1 μeq/min, P < 0.05) and decreased fractional reabsorption of DSD compared with control (72.2 ± 3.4%, P < 0.05) at similar mean arterial pressures (91 ± 6 vs. 92 ± 3 mmHg, P > 0.05). These results provide in vivo evidence that ANP-mediated increases in DSD alone exert modest effects on sodium excretion and that inhibition of fractional reabsorption of distal sodium delivery is requisite for the augmented natriuresis in response to the higher dose of ANP or in Npr1 gene-duplicated mice.

scholarly journals Role of FQQI motif in the internalization, trafficking, and signaling of guanylyl-cyclase/natriuretic peptide receptor-A in cultured murine mesangial cells

2016 ◽  
Vol 310 (1) ◽  
pp. F68-F84 ◽  
Author(s):  
Indra Mani ◽  
Renu Garg ◽  
Kailash N. Pandey
Keyword(s):  
Natriuretic Peptide ◽  
Guanylyl Cyclase ◽  
Mesangial Cells ◽  
Adaptor Protein ◽  
Target Cells ◽  
Natriuretic Peptide Receptor ◽  
Subcellular Trafficking ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A

Binding of the cardiac hormone atrial natriuretic peptide (ANP) to transmembrane guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA), produces the intracellular second messenger cGMP in target cells. To delineate the critical role of an endocytic signal in intracellular sorting of the receptor, we have identified a FQQI (Phe790, Gln791, Gln792, and Ile793) motif in the carboxyl-terminal region of NPRA. Mouse mesangial cells (MMCs) were transiently transfected with the enhanced green fluorescence protein (eGFP)-tagged wild-type (WT) and mutant constructs of eGFP-NPRA. The mutation FQQI/AAAA, in the eGFP-NPRA cDNA sequence, markedly attenuated the internalization of mutant receptors by almost 49% compared with the WT receptor. Interestingly, we show that the μ1B subunit of adaptor protein-1 binds directly to a phenylalanine-based FQQI motif in the cytoplasmic tail of the receptor. However, subcellular trafficking indicated that immunofluorescence colocalization of the mutated receptor with early endosome antigen-1 (EEA-1), lysosome-associated membrane protein-1 (LAMP-1), and Rab 11 marker was decreased by 57% in early endosomes, 48% in lysosomes, and 42% in recycling endosomes, respectively, compared with the WT receptor in MMCs. The receptor containing the mutated motif (FQQI/AAAA) also produced a significantly decreased level of intracellular cGMP during subcellular trafficking than the WT receptor. The coimmunoprecipitation assay confirmed a decreased level of colocalization of the mutant receptor with subcellular compartments during endocytic processes. The results suggest that the FQQI motif is essential for the internalization and subcellular trafficking of NPRA during the hormone signaling process in intact MMCs.

Genetic disruption of guanylyl cyclase/natriuretic peptide receptor-A upregulates ACE and AT1 receptor gene expression and signaling: role in cardiac hypertrophy

2007 ◽  
Vol 31 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Elangovan Vellaichamy ◽  
Di Zhao ◽  
Naveen Somanna ◽  
Kailash N. Pandey
Keyword(s):  
Gene Expression ◽  
Cardiac Hypertrophy ◽  
Natriuretic Peptide ◽  
Guanylyl Cyclase ◽  
Heart Weight ◽  
Natriuretic Peptide Receptor ◽  
Wild Type ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A ◽  
Npr1 Gene

Guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) signaling antagonizes the physiological effects mediated by the renin-angiotensin system (RAS). The objective of this study was to determine whether the targeted-disruption of Npr1 gene (coding for GC-A/NPRA) leads to the activation of cardiac RAS genes involved on the hypertrophic remodeling process. The Npr1 gene-knockout ( Npr1 −/−) mice showed 30–35 mmHg higher systolic blood pressure (SBP) and a 63% greater heart weight-to-body weight (HW/BW) ratio compared with wild-type ( Npr1 +/+) mice. The mRNA levels of both angiotensin-converting enzyme and angiotensin II type 1a receptor were increased by three- and fourfold, respectively, in Npr1 −/− null mutant mice hearts compared with the wild-type Npr1 +/+ mice hearts. In parallel, the expression levels of interleukin-6 and tumor necrosis factor-α were increased by four- to fivefold, in Npr1 −/− mice hearts compared with control animals. The NF-κB binding activity in nuclear extracts of Npr1 −/− mice hearts was increased by fourfold compared with wild-type Npr1 +/+ mice hearts. Treatments with captopril or hydralazine equally attenuated SBP; however, only captopril significantly decreased the HW/BW ratio and suppressed cytokine gene expression in Npr1 −/− mice hearts. The ventricular cGMP level was reduced by almost sixfold in Npr1 −/− mice compared with wild-type control mice. The results of the present study indicate that disruption of NPRA/cGMP signaling leads to the augmented expression of cardiac RAS pathways that promote the development of cardiac hypertrophy and remodeling.

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