scholarly journals Heat Shock Protein 70 and CHIP Promote Nox4 Ubiquitination and Degradation within the Losartan Antioxidative Effect in Proximal Tubule Cells

2015 ◽  
Vol 36 (6) ◽  
pp. 2183-2197 ◽  
Author(s):  
Andrea F. Gil Lorenzo ◽  
Valeria V. Costantino ◽  
Martin López Appiolaza ◽  
Valeria Cacciamani ◽  
Maria E. Benardon ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Proximal Tubule ◽  
Ros Generation ◽  
Antioxidative Effect ◽  
Proximal Tubule Cells ◽  
Caveolin 1 ◽  
Protein Levels ◽  
Hsp70 Protein

Background: Angiotensin II/Angiotensin II type 1 receptor (AT1R) effects are dependent on ROS production stimulated by NADPH oxidase activation. Hsp70 regulates a diverse set of signaling pathways through their interactions with proteins. CHIP is a E3 ubiquitin ligase that targets proteins for polyubiquitination and degradation. Aim: We study whether Hsp70/CHIP contribute to the negative regulation of Nox4 after AT1R blockage. Methods/Results: Primary culture of proximal tubule epithelial cells (PTCs) from SHR and WKY were stimulated with Angiotensin II (AII) or treated with Losartan (L) or Losartan plus Angiotensin II (L+AII). Losartan decreased AT1R and Nox4 while enhancing caveolin-1 and Hsp70 protein expression in SHR PTCs. Immunoprecipitation and immunofluorescence proved interaction and colocalization of increased Hsp70/CHIP with decreased Nox4 in SHR PTCs (L) vs (All). Hsp72 knockdown resulted in enhanced Nox4 protein levels, NADPH oxidase activity and ROS generation in (L+AII) revealing that Losartan was unable to abrogate AII effects on Nox4 expression and oxidative activity. Moreover, MG132 exposed PTCs (L) demostrated blocked ubiquitinated Nox4 degradation and increased colocalization of Nox4/Ubiquitin by inmunofluorescence. Conversely, Hsp72 depletion reduced Nox4/Ubiquitin colocalization causing Nox4 upregulation due to proteosomal degradation inhibition, although Losartan treatment. Conclusion: Our study demonstrates that Hsp70 and CHIP mediates the ubiquitination and proteasomal degradation of Nox4 as part of the antioxidative effect of Losartan in SHR.

scholarly journals Low dose ouabain stimulates Na K ATPase α1 subunit association with angiotensin II type 1 receptor in renal proximal tubule cells

2016 ◽  
Vol 1863 (11) ◽  
pp. 2624-2636 ◽  
Author(s):  
Corey J. Ketchem ◽  
Clayton D. Conner ◽  
Rebecca D. Murray ◽  
Madalyn DuPlessis ◽  
Eleanor D. Lederer ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Proximal Tubule ◽  
Low Dose ◽  
Renal Proximal Tubule ◽  
Proximal Tubule Cells ◽  
Tubule Cells ◽  
Renal Proximal Tubule Cells ◽  
Α1 Subunit

scholarly journals Interaction of Angiotensin II Type 1 and D 5 Dopamine Receptors in Renal Proximal Tubule Cells

Hypertension ◽  
2005 ◽  
Vol 45 (4) ◽  
pp. 804-810 ◽  
Author(s):  
Chunyu Zeng ◽  
Zhiwei Yang ◽  
Zheng Wang ◽  
John Jones ◽  
Xiaoyan Wang ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Proximal Tubule ◽  
Dopamine Receptors ◽  
Renal Proximal Tubule ◽  
Proximal Tubule Cells ◽  
Tubule Cells ◽  
Renal Proximal Tubule Cells

Reactive Oxygen Species-Mediated Homologous Downregulation of Angiotensin II Type 1 Receptor Mrna by Angiotensin II

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 688-688
Author(s):  
Toshihiro Ichiki ◽  
Kotaro Takeda ◽  
Akira Takeshita
Keyword(s):  
Reactive Oxygen Species ◽  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Mrna Expression ◽  
Crucial Role ◽  
Oxygen Species ◽  
Ang Ii ◽  
Stimulation Of

58 Recent studies suggest a crucial role of reactive oxygen species (ROS) for the signaling of Angiotensin II (Ang II) through type 1 Ang II receptor (AT1-R). However, the role of ROS in the regulation of AT1-R expression has not been explored. In this study, we examined the effect of an antioxidant on the homologous downregulation of AT1-R by Ang II. Ang II (10 -6 mol/L) decreased AT1-R mRNA with a peak suppression at 6 hours of stimulation in rat aortic vascular smooth muscle cells (VSMC). Ang II dose-dependently (10 -8 -10 -6 ) suppressed AT1-R mRNA at 6 hours of stimulation. Preincubation of VSMC with N-acetylcysteine (NAC), a potent antioxidant, almost completely inhibited the Ang II-induced downregulation of AT1-R mRNA. The effect of NAC was due to stabilization of the AT1-R mRNA that was destabilized by Ang II. Ang II did not affect the promoter activity of AT1-R gene. Diphenylene iodonium (DPI), an inhibitor of NADH/NADPH oxidase failed to inhibit the Ang II-induced AT1-R mRNA downregulation. The Ang II-induced AT1-R mRNA downregulation was also blocked by PD98059, an extracellular signal-regulated protein kinase (ERK) kinase inhibitor. Ang II-induced ERK activation was inhibited by NAC as well as PD98059 whereas DPI did not inhibit it. To confirm the role of ROS in the regulation of AT1-R mRNA expression, VSMC were stimulated with H 2 O 2 . H 2 O 2 suppressed the AT1-R mRNA expression and activated ERK. These results suggest that production of ROS and activation of ERK are critical for downregulation of AT1-R mRNA. The differential effect of NAC and DPI on the downregulation of AT1-R mRNA may suggest the presence of other sources than NADH/NADPH oxidase pathway for ROS in Ang II signaling. Generation of ROS through stimulation of AT1-R not only mediates signaling of Ang II but may play a crucial role in the adaptation process of AT1-R to the sustained stimulation of Ang II.

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