ACE as a Mechanosensor to Shear Stress Influences the Control of Its Own Regulation via Phosphorylation of Cytoplasmic Ser1270

Valerio Garrone Barauna,Jose Eduardo Krieger,Luciene Cristina Gastalho Campos,Ayumi Aurea Miyakawa

doi:10.1371/journal.pone.0022803

Valerio Garrone Barauna, Jose Eduardo Krieger + Show 2 more

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https://doi.org/10.1371/journal.pone.0022803

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Journal: PloS one	Publication Date: Aug 25, 2011
Citations: 44	License type: CC BY 4.0

Affiliation: Universidade de São Paulo

Abstract

ObjectivesWe tested whether angiotensin converting enzyme (ACE) and phosphorylation of Ser1270 are involved in shear-stress (SS)-induced downregulation of the enzyme.Methods and ResultsWestern blotting analysis showed that SS (18 h, 15 dyn/cm2) decreases ACE expression and phosphorylation as well as p-JNK inhibition in human primary endothelial cells (EC). CHO cells expressing wild-type ACE (wt-ACE) also displayed SS-induced decrease in ACE and p-JNK. Moreover, SS decreased ACE promoter activity in wt-ACE, but had no effect in wild type CHO or CHO expressing ACE without either the extra- or the intracellular domains, and decreased less in CHO expressing a mutated ACE at Ser1270 compared to wt-ACE (13 vs. 40%, respectively). The JNK inhibitor (SP600125, 18 h), in absence of SS, also decreased ACE promoter activity in wt-ACE. Finally, SS-induced inhibition of ACE expression and phosphorylation in EC was counteracted by simultaneous exposure to an ACE inhibitor.ConclusionsACE displays a key role on its own downregulation in response to SS. This response requires both the extra- and the intracellular domains and ACE Ser1270, consistent with the idea that the extracellular domain behaves as a mechanosensor while the cytoplasmic domain elicits the downstream intracellular signaling by phosphorylation on Ser1270.

Highlights

Angiotensin-converting enzyme (ACE) is a key component of the renin-angiotensin system, which regulates blood pressure, electrolyte balance and fluid homeostasis [1,2]
This response requires both the extraand the intracellular domains and ACE Ser1270, consistent with the idea that the extracellular domain behaves as a mechanosensor while the cytoplasmic domain elicits the downstream intracellular signaling by phosphorylation on Ser1270
SS (18 h, 15 dyn/cm2) in human SVEC is associated with a decrease in ACE protein expression (Figure 1 A), to what we had previously observed in the rat aorta for both activity and mRNA levels while nitric oxide synthase activity increased [10]

Summary

Introduction

Angiotensin-converting enzyme (ACE) is a key component of the renin-angiotensin system, which regulates blood pressure, electrolyte balance and fluid homeostasis [1,2]. ACE is a transmembrane protein expressed on the surface of many cell types that can process different peptides through two active catalytic sites in the extracellular domain, including angiotensin I to generate the vasoconstrictor peptide angiotensin II and the degradation of bradykinin [3]. The mechanotransduction involved in these processes is not fully elucidated and several mechanosensors have been described. They are usually transmembrane proteins, which can sense the extracellular hemodynamic stimulus and convert it in chemical intracellular response [5]. Phosphorylated c-jun activates AP-1 transcription factor and increase ACE expression [7,8,9]

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