scholarly journals Targeted Disruption of Guanylyl Cyclase-A/Natriuretic Peptide Receptor-A Gene Provokes Renal Fibrosis and Remodeling in Null Mutant Mice: Role of Proinflammatory Cytokines

Endocrinology ◽  
2010 ◽  
Vol 151 (12) ◽  
pp. 5841-5850 ◽  
Author(s):  
Subhankar Das ◽  
Edward Au ◽  
Stephen T. Krazit ◽  
Kailash N. Pandey
Keyword(s):  
Proinflammatory Cytokines ◽  
Guanylyl Cyclase ◽  
Renal Fibrosis ◽  
Natriuretic Peptide Receptor ◽  
Null Mutant ◽  
Targeted Disruption ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A ◽  
Null Mutant Mice

scholarly journals Activation of IKK/NF-κB provokes renal inflammatory responses in guanylyl cyclase/natriuretic peptide receptor-A gene-knockout mice

2012 ◽  
Vol 44 (7) ◽  
pp. 430-442 ◽  
Author(s):  
Subhankar Das ◽  
Ramu Periyasamy ◽  
Kailash N. Pandey
Keyword(s):  
Natriuretic Peptide ◽  
Proinflammatory Cytokines ◽  
Guanylyl Cyclase ◽  
Renal Fibrosis ◽  
Gene Knockout ◽  
Mutant Mice ◽  
Pyrrolidine Dithiocarbamate ◽  
Natriuretic Peptide Receptor ◽  
Peptide Receptor ◽  
Natriuretic Peptide Receptor A

The present study was aimed at determining the consequences of the disruption of guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene ( Npr1) on proinflammatory responses of nuclear factor kappa B, inhibitory kappa B kinase, and inhibitory kappa B alpha (NF-κB, IKK, IκBα) in the kidneys of mutant mice. The results showed that the disruption of Npr1 enhanced the renal NF-κB binding activity by 3.8-fold in 0-copy (−/−) mice compared with 2-copy (+/+) mice. In parallel, IKK activity and IκBα protein phosphorylation were increased by 8- and 11-fold, respectively, in the kidneys of 0-copy mice compared with wild-type mice. Interestingly, IκBα was reduced by 80% and the expression of proinflammatory cytokines and renal fibrosis were significantly enhanced in 0-copy mice than 2-copy mice. Treatment of 0-copy mice with NF-κB inhibitors andrographolide, pyrrolidine dithiocarbamate, and etanercept showed a substantial reduction in renal fibrosis, attenuation of proinflammatory cytokines gene expression, and significantly reduced IKK activity and IkBα phosphorylation. These findings indicate that the systemic disruption of Npr1 activates the renal NF-κB pathways in 0-copy mice, which transactivates the expression of various proinflammatory cytokines to initiate renal remodeling; however, inhibition of NF-κB pathway repairs the abnormal renal pathology in mutant 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.

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