Functional Exploration of Conserved Sequences in the Distal Face of Angiotensinogen - Brief Report

Authors

Naofumi Amioka, University of Kentucky
Chia-Hua Wu, University of KentuckyFollow
Hisashi Sawada, University of KentuckyFollow
Sohei Ito, University of KentuckyFollow
Alex C. Pettey, University of Kentucky
Congqing Wu, University of KentuckyFollow
Jessica J. Moorleghen, University of KentuckyFollow
Deborah A. Howatt, University of KentuckyFollow
Gregory A. Graf, University of KentuckyFollow
Craig W. Vander Kooi, University of KentuckyFollow
Alan Daugherty, University of KentuckyFollow
Hong S. Lu, University of KentuckyFollow

Abstract

BACKGROUND: Angiotensinogen (AGT) is an essential component in the renin-angiotensin system. AGT has highly conserved sequences in the loop and β-sheet regions among species; however, their functions have not been studied.

METHODS: Adeno-associated viral vector (AAV) serotype 2/8 encoding mouse AGT with mutations of conserved sequences in the loop (AAV.loop-Mut), β-sheet (AAV.βsheet-Mut), or both regions (AAV.loop/βsheet-Mut) was injected into male hepatocyte-specific AGT-deficient (hepAGT−/− ) mice in an LDL (low-density lipoprotein) receptor–deficient background. AAV containing mouse wild-type AGT (AAV.mAGT) or a null vector (AAV.null) were used as controls. Two weeks after AAV administration, all mice were fed a western diet for 12 weeks. To determine how AGT secretion is regulated in hepatocytes, AAVs containing the above mutations were transducted into HepG2 cells.

RESULTS: In hepAGT−/− mice infected with AAV.loop-Mut or βsheet-Mut, plasma AGT concentrations, systolic blood pressure, and atherosclerosis were comparable to those in AAV.mAGT-infected mice. Interestingly, plasma AGT concentrations, systolic blood pressure, and atherosclerotic lesion size in hepAGT−/− mice infected with AAV.loop/βsheet-Mut were not different from mice infected with AAV.null. In contrast, hepatic Agt mRNA abundance was elevated to a comparable magnitude as AAV.mAGT- infected mice. Immunostaining showed that AGT protein was accumulated in hepatocytes of mice infected with AAV.loop/βsheet- Mut or HepG2 cells transducted with AAV.loop/βsheet-Mut. Accumulated AGT was not located in the endoplasmic reticulum.

CONCLUSIONS: The conserved sequences in either the loop or β-sheet region individually have no effect on AGT regulation, but the conserved sequences in both regions synergistically contribute to the secretion of AGT from hepatocytes.

Document Type

Article

Publication Date

8-2023

Notes/Citation Information

© 2023 American Heart Association, Inc.

Digital Object Identifier (DOI)

https://doi.org/10.1161/ATVBAHA.122.318930

Funding Information

This research work is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health (R01HL139748). The content in this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Repository Citation

Amioka, Naofumi; Wu, Chia-Hua; Sawada, Hisashi; Ito, Sohei; Pettey, Alex C.; Wu, Congqing; Moorleghen, Jessica J.; Howatt, Deborah A.; Graf, Gregory A.; Vander Kooi, Craig W.; Daugherty, Alan; and Lu, Hong S., "Functional Exploration of Conserved Sequences in the Distal Face of Angiotensinogen - Brief Report" (2023). Saha Cardiovascular Research Center Faculty Publications. 83.
https://uknowledge.uky.edu/cvrc_facpub/83