Cardiology Commons^™

One Amino Acid Change Of Angiotensin Ii Diminishes Its Effects On Abdominal Aortic Aneurysm, Ya Wang, Yinchuan Xu, Congqing Wu, Hongguang Xia, Yingchao Wang, Jinliang Nan, Jinghai Chen, Hong Yu, Wei Zhu, Peng Shi, Alan Daugherty, Hong S. Lu, Jian'an Wang

Saha Cardiovascular Research Center Faculty Publications

Angiotensin (Ang) A is formed by the decarboxylation of the N terminal residue of AngII. The present study determined whether this one amino acid change impacted effects of AngII on abdominal aortic aneurysm (AAA) formation in mice. Computational analyses implicated that AngA had comparable binding affinity to both AngII type 1 and 2 receptors as AngII. To compare effects of these two octapeptides in vivo, male low-density lipoprotein receptor (Ldlr) or apolipoprotein E (Apoe) deficient mice were infused with either AngII or AngA (1 μg/kg/min) for 4 weeks. While AngII infusion induced AAA consistently in …

Deletion Of The Nr4a Nuclear Receptor Nor1 In Hematopoietic Stem Cells Reduces Inflammation But Not Abdominal Aortic Aneurysm Formation, Hua Qing, Karrie L. Jones, Elizabeth B. Heywood, Hong Lu, Alan Daugherty, Dennis Bruemmer

Pharmacology and Nutritional Sciences Faculty Publications

Background: The NR4A3 orphan nuclear hormone receptor, NOR1, functions as a constitutively active transcription factor to regulate inflammation, proliferation, and cell survival during pathological vascular remodeling. Inflammatory processes represent key mechanisms leading to abdominal aortic aneurysm (AAA) formation. However, a role of NOR1 in AAA formation has not been investigated previously.

Methods: Inflammatory gene expression was analyzed in bone marrow-derived macrophages isolated from NOR1-deficient mice. Low-density lipoprotein receptor-deficient (LDLr^−/−) mice were irradiated and reconstituted with hematopoietic stem cells obtained from NOR1−/− or wild-type littermate mice. Animals were infused with angiotensin II and fed a diet enriched in saturated …

Targeting Hepatic Heparin-Binding Egf-Like Growth Factor (Hb-Egf) Induces Anti-Hyperlipidemia Leading To Reduction Of Angiotensin Ii-Induced Aneurysm Development, Seonwook Kim, Lihua Yang, Seongu Kim, Richard G. Lee, Mark J. Graham, Judith A. Berliner, Aldons J. Lusis, Lei Cai, Ryan E. Temel, Debra L. Rateri, Sangderk Lee

Saha Cardiovascular Research Center Faculty Publications

Objective

The upregulated expression of heparin binding EGF-like growth factor (HB-EGF) in the vessel and circulation is associated with risk of cardiovascular disease. In this study, we tested the effects of HB-EGF targeting using HB-EGF-specific antisense oligonucleotide (ASO) on the development of aortic aneurysm in a mouse aneurysm model.

Approach and results

Low-density lipoprotein receptor (LDLR) deficient mice (male, 16 weeks of age) were injected with control and HB-EGF ASOs for 10 weeks. To induce aneurysm, the mice were fed a high fat diet (22% fat, 0.2% cholesterol; w/w) at 5 week point of ASO administration and infused with angiotensin …

Tgf-Β Neutralization Enhances Angii-Induced Aortic Rupture And Aneurysm In Both Thoracic And Abdominal Regions, Xiaofeng Chen, Debra L. Rateri, Deborah A. Howatt, Anju Balakrishnan, Jessica J. Moorleghen, Lisa A. Cassis, Alan Daugherty

Saha Cardiovascular Research Center Faculty Publications

AngII and TGF-β interact in development of thoracic and abdominal aortic diseases, although there are many facets of this interaction that have not been clearly defined. The aim of the present study was to determine the effects of TGF-β neutralization on AngII induced-aortic pathologies. Male C57BL/6J mice were administered with either a rabbit or mouse TGF-β neutralizing antibody and then infused with AngII. The rabbit TGF-β antibody modestly reduced serum TGF-β concentrations, with no significant enhancements to AngII-induced aneurysm or rupture. Administration of this rabbit TGF-β antibody in mice led to high serum titers against rabbit IgG that may have …

Telemetric Blood Pressure Assessment In Angiotensin Ii-Infused Apoe-/- Mice: 28 Day Natural History And Comparison To Tail-Cuff Measurements, Christopher M. Haggerty, Andrea C. Mattingly, Ming C. Gong, Wen Su, Alan Daugherty, Brandon K. Fornwalt

Saha Cardiovascular Research Center Faculty Publications

Abdominal aortic aneurysm (AAA) is a disease of the aortic wall, which can progress to catastrophic rupture. Assessment of mechanical characteristics of AAA, such as aortic distensibility, may provide important insights to help identify at-risk patients and understand disease progression. While the majority of studies on this topic have focused on retrospective patient data, recent studies have used mouse models of AAA to prospectively evaluate the evolution of aortic mechanics. Quantification of aortic distensibility requires accurate measurement of arterial blood pressure, particularly pulse pressure, which is challenging to perform accurately in murine models. We hypothesized that volume/pressure tail-cuff measurements of …

Aortic Aneurysms In Loeys-Dietz Syndrome - A Tale Of Two Pathways?, Frank Davis, Debra L. Rateri, Alan Daugherty

Saha Cardiovascular Research Center Faculty Publications

Loeys-Dietz syndrome (LDS) is a connective tissue disorder that is characterized by skeletal abnormalities, craniofacial malformations, and a high predisposition for aortic aneurysm. In this issue of the JCI, Gallo et al. developed transgenic mouse strains harboring missense mutations in the genes encoding type I or II TGF-β receptors. These mice exhibited several LDS-associated phenotypes. Despite being functionally defective, the mutated receptors enhanced TGF-β signaling in vivo, inferred by detection of increased levels of phosphorylated Smad2. Aortic aneurysms in these LDS mice were ablated by treatment with the Ang II type 1 (AT1) receptor antagonist losartan. The results from this …

Calpain-2 Compensation Promotes Angiotensin Ii-Induced Ascending And Abdominal Aortic Aneurysms In Calpain-1 Deficient Mice, Venkateswaran Subramanian, Jessica J. Moorleghen, Anju Balakrishnan, Deborah A. Howatt, Athar H. Chishti, Haruhito A. Uchida

Saha Cardiovascular Research Center Faculty Publications

BACKGROUND AND OBJECTIVE: Recently, we demonstrated that angiotensin II (AngII)-infusion profoundly increased both aortic protein and activity of calpains, calcium-activated cysteine proteases, in mice. In addition, pharmacological inhibition of calpain attenuated AngII-induced abdominal aortic aneurysm (AA) in mice. Recent studies have shown that AngII infusion into mice leads to aneurysmal formation localized to the ascending aorta. However, the precise functional contribution of calpain isoforms (-1 or -2) in AngII-induced abdominal AA formation is not known. Similarly, a functional role of calpain in AngII-induced ascending AA remains to be defined. Using BDA-410, an inhibitor of calpains, and calpain-1 genetic deficient mice, …

Regional Variation In Aortic At1b Receptor Mrna Abundance Is Associated With Contractility But Unrelated To Atherosclerosis And Aortic Aneurysms, Aruna Poduri, A. Phillip Owens, Deborah A. Howatt, Jessica J. Moorleghen, Anju Balakrishnan, Lisa A. Cassis, Alan Daugherty

Pharmacology and Nutritional Sciences Faculty Publications

BACKGROUND: Angiotensin II (AngII), the main bioactive peptide of the renin angiotensin system, exerts most of its biological actions through stimulation of AngII type 1 (AT1) receptors. This receptor is expressed as 2 structurally similar subtypes in rodents, termed AT1a and AT1b. Although AT1a receptors have been studied comprehensively, roles of AT1b receptors in the aorta have not been defined.

METHODOLOGY/RESULTS: We initially compared the regional distribution of AT1b receptor mRNA with AT1a receptor mRNA in the aorta. mRNA abundance of both subtypes increased from the proximal to the distal aorta, with the greatest abundance in the infra-renal region. Corresponding …

Angiotensin Ii Promotes Atherosclerotic Lesions And Aneurysms In Apolipoprotein E-Deficient Mice, Alan Daugherty, Michael W. Manning, Lisa A. Cassis

Gill Heart & Vascular Institute Faculty Publications

Increased plasma concentrations of angiotension II (Ang II) have been implicated in atherogenesis. To examine this relationship directly, we infused Ang II or vehicle for 1 month via osmotic minipumps into mature apoE^–/– mice. These doses of Ang II did not alter arterial blood pressure, body weight, serum cholesterol concentrations, or distribution of lipoprotein cholesterol. However, Ang II infusions promoted an increased severity of aortic atherosclerotic lesions. These Ang II–induced lesions were predominantly lipid-laden macrophages and lymphocytes; moreover, Ang II promoted a marked increase in the number of macrophages present in the adventitial tissue underlying lesions. Unexpectedly, pronounced abdominal …