Abstract: SA-PO772
Novel Truncated ACE2 Fusion Protein with Extended Half-Life Is Delivered to the Kidney and Ameliorates Angiotensin II-Induced Hypertension
Session Information
- CKD: Mechanisms - III
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2103 CKD (Non-Dialysis): Mechanisms
Authors
- Wysocki, Jan, Northwestern University, Chicago, Illinois, United States
- Schulze, Arndt, Northwestern University, Chicago, Illinois, United States
- Liu, Pan, Northwestern University, Chicago, Illinois, United States
- Ye, Minghao, Northwestern University, Chicago, Illinois, United States
- Haney, Chad R., Northwestern University, Chicago, Illinois, United States
- Zhao, Ming, Northwestern University, Chicago, Illinois, United States
- Batlle, Daniel, Northwestern University, Chicago, Illinois, United States
Background
ACE2 converts angiotensin (Ang)II to the renoprotective peptide, Ang (1-7), thereby providing a mechanism to downregulate the renin-angiotensin system (RAS). Targeting kidney RAS using native ACE2 might not be effective due the large size (~110 kDa) that prevents its glomerular filtration and subsequent tubular uptake.
Methods
To circumvent this limitation, ACE2 truncate (ACE2 1-619) was generated through C-terminal truncation of the native ACE2 and subsequently fused with albumin binding domain (ABD). Enzyme activity of the chimeric protein was confirmed using ACE2-specific substrate Mca-APK-Dnp and its inhibition by MLN-4760 (ACE2-specific inhibitor).
Results
In Western blot the fusion protein appeared as a single band at the apparent molecular weight of ~75 kDa, as expected from its amino acid sequence. In keeping with the goal of our original design, ACE2 1-619ABD exhibited a markedly extended circulatory residence longevity than naked ACE2 1-619 or native ACE2 1-740. The extended in vivo half-life was confirmed in a model of angiotensin II-induced hypertension whereby an increase in SBP was mitigated by the ACE2 1-619ABD for up to 7 days after a single i.p. bolus injection (1 ug/g BW) (Figure). In SPECT/CT imaging, after i.v. injection of Tc99m-labeled ACE2 1-619ABD, there was a significant retention in kidney cortex (6.3±0.5% of whole body (WB) radioactivity) as compared to trace retention generated by the native Tc99m-ACE2 1-740 (1.2±0.2% WB).
Conclusion
The novel ACE2 truncate fused with ABD is enzymatically active, exhibit an extended in vivo half-life, and is taken up by kidney cortex. These features might be potentially favorable for developing a new approach to target kidney disease with intrarenal RAS overactivity.
Funding
- NIDDK Support