scholarly journals HIF1α in aortic aneurysms and beyond

2017 ◽  
Vol 131 (7) ◽  
pp. 621-623
Author(s):  
Tomoki Hashimoto ◽  
Victor Rizzo
Keyword(s):  
Vessel Wall ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Aortic Aneurysms ◽  
Endogenous Inhibitors ◽  
Abdominal Aortic ◽  
High Prevalence ◽  
Basic Studies ◽  
New Discovery

Abdominal aortic aneurysm (AAA) is a permanent expansion of the vessel wall with a high prevalence in those 65 years of age and older. Aneurysms are prone to dissection and rupture that carry a mortality rate of over 85%. Currently, surgical repair is the only option to treat this disease. The need to intervene prior to these events has set off a flurry of basic studies in an effort to understand the cellular and molecular mechanisms that govern AAA formation, progression and rupture. In the present study, the role of myeloid cells in contributing to AAA development has been confirmed. More specifically, the transcription factor, hypoxia-inducible factor-1α (HIF1α), was demonstrated to be a necessary component for regulating the expression of extracellular matrix modifying enzymes and their endogenous inhibitors in these cells. This new discovery may lead to therapeutic targets to prohibit the degradation and weakening of the vessel wall with the hope of limiting AAA formation and/or growth.

scholarly journals Circular RNA Expression: Its Potential Regulation and Function in Abdominal Aortic Aneurysms

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Yanshuo Han ◽  
Hao Zhang ◽  
Ce Bian ◽  
Chen Chen ◽  
Simei Tu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Human Life ◽  
Abdominal Aortic Aneurysms ◽  
Circular Rna ◽  
Aortic Aneurysms ◽  
Current Evidence ◽  
Circular Rnas ◽  
Regulatory Pathways ◽  
Abdominal Aortic

Abdominal aortic aneurysms (AAAs) have posed a great threat to human life, and the necessity of its monitoring and treatment is decided by symptomatology and/or the aneurysm size. Accumulating evidence suggests that circular RNAs (circRNAs) contribute a part to the pathogenesis of AAAs. circRNAs are novel single-stranded RNAs with a closed loop structure and high stability, having become the candidate biomarkers for numerous kinds of human disorders. Besides, circRNAs act as molecular “sponge” in organisms, capable of regulating the transcription level. Here, we characterize that the molecular mechanisms underlying the role of circRNAs in AAA development were further elucidated. In the present work, studies on the biosynthesis, bibliometrics, and mechanisms of action of circRNAs were aims comprehensively reviewed, the role of circRNAs in the AAA pathogenic mechanism was illustrated, and their potential in diagnosing AAAs was examined. Moreover, the current evidence about the effects of circRNAs on AAA development through modulating endothelial cells (ECs), macrophages, and vascular smooth muscle cells (VSMCs) was summarized. Through thorough investigation, the molecular mechanisms underlying the role of circRNAs in AAA development were further elucidated. The results demonstrated that circRNAs had the application potential in the diagnosis and prevention of AAAs in clinical practice. The study of circRNA regulatory pathways would be of great assistance to the etiologic research of AAAs.

Abstract 468: HIF-1α Mediates Initiation and Progression of Experimental Abdominal Aortic Aneurysms

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Baohui Xu ◽  
Naoki Fujimura ◽  
Hongping Deng ◽  
Haojuan Xuan ◽  
Yuko Furusho ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Myeloid Cell ◽  
Aortic Aneurysms ◽  
Conditional Knockout ◽  
Elastin Degradation ◽  
Abdominal Aortic ◽  
Life Threatening ◽  
Reduced Time

Abdominal aortic aneurysm (AAA) is a life-threatening chronic disease. Although low mural oxygen tension is present in the aneurysmal aorta, with increased hypoxia inducible factor (HIF)-1α expression, the role of HIF-1α in AAA pathogenesis remains uncertain. These experiments separately examined the influences of myeloid cell-specific HIF-1α deletion, as well as pharmacologic HIF-1α inhibition, on experimental AAA progression. Methods: AAAs were created via intra-aortic porcine pancreatic elastase (PPE) infusion in myeloid cell-specific HIF-1α conditional knockout (Lyz2 Cre+/HIF-1α Flox+/+) or control (HIF-1α Flox+/+) mice, as well as C57BL/6J mice treated with HIF-1α inhibitors or vehicle. AAA formation and progression was evaluated in vivo via ultrasonography, and histology at sacrifice. Results: HIF-1α mRNA expression was remarkably elevated in aneurysmal (PPE) as compared to non-aneurysmal (PBS), aortae. Flow cytometry detected nearly 65% of aortic CD11b+ myeloid cells expressed HIF-1α. Myeloid cell HIF-1α deletion reduced time-dependent aneurysmal enlargement noted following PPE infusion. Similar inhibition was observed in WT mice following daily treatment with acriflavine or doxorubicin (1 mg/kg), beginning 3 days prior to PPE infusion. Histologically, both myeloid cell HIF-1α deletion and pharmacologic HIF-1α inhibition attenuated medial elastin degradation and smooth muscle cell depletion, with reduced aortic mural macrophage and neovessel density compared to the corresponding controls. Conclusion: HIF-1α is an essential modulator of AAA pathogenesis, thus representing a novel pharmacologic target for medical disease management.

Effects of long-term chloroquine administration on the natural history of aortic aneurysms in mice

2015 ◽  
Vol 93 (8) ◽  
pp. 641-648 ◽  
Author(s):  
Azza Ramadan ◽  
Mark D. Wheatcroft ◽  
Adrian Quan ◽  
Krishna K. Singh ◽  
Fina Lovren ◽  
...  
Keyword(s):  
Natural History ◽  
Thrombus Formation ◽  
Aortic Aneurysms ◽  
Ang Ii ◽  
Abdominal Aortic ◽  
Suprarenal Aorta ◽  
History Of ◽  
Categorical Distribution

Autophagy regulates cellular homeostasis and integrates the cellular pro-survival machinery. We investigated the role of autophagy in the natural history of murine abdominal aortic aneurysms (AAA). ApoE−/− mice were implanted with saline- or angiotensin II (Ang-II)-filled miniosmotic pumps then treated with either the autophagy inhibitor chloroquine (CQ; 50 mg·(kg body mass)–1·day–1, by intraperitoneal injection) or saline. Ang-II-elicited aneurysmal expansion of the suprarenal aorta coupled with thrombus formation were apparent 8 weeks later. CQ had no impact on the incidence (50% for Ang-II compared with 46.2% for Ang-II + CQ; P = NS) and categorical distribution of aneurysms. The markedly reduced survival rate observed with Ang-II (57.1% for Ang-II compared with 100% for saline; P < 0.05) was unaffected by CQ (61.5% for Ang-II + CQ; P = NS compared with Ang-II). CQ did not affect the mean maximum suprarenal aortic diameter (1.91 ± 0.19 mm for Ang-II compared with 1.97 ± 0.21 mm for Ang-II + CQ; P = NS). Elastin fragmentation, collagen accumulation, and smooth muscle attrition, which were higher in Ang-II-treated mice, were unaffected by CQ treatment. Long-term CQ administration does not affect the natural history and prognosis of experimental AAA, suggesting that global loss of autophagy is unlikely to be a causal factor in the development of aortic aneurysms. Manipulation of autophagy as a mechanism to reduce AAA may need re-evaluation.

Abstract 667: The Role of Aortic Wall-Nuclear Factor- kappa B (NF-kB) Signaling in Formation of Dissecting Aortic Aneurysms

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Talha Ijaz ◽  
Hong Sun ◽  
Adrian Recinos ◽  
Ronald G Tilton ◽  
Allan R Brasier
Keyword(s):  
Flow Cytometry ◽  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Aortic Wall ◽  
Aortic Rupture ◽  
Aortic Aneurysms ◽  
Tunel Staining ◽  
Abdominal Aortic ◽  
Significant Difference

Introduction: Abdominal aortic aneurysm is a devastating disease since it can lead to aortic rupture and instantaneous death. We previously demonstrated that IL-6 secreted from the aortic wall is necessary for the development of abdominal aortic aneurysm and dissection (AAD). Since IL-6 is a NF-kB/RelA dependant gene, we investigated the role of aortic wall- NF-kB/RelA signaling in the development of AAD. Methods and Results: To test the role of aortic wall-RelA, we utilized Cre-Lox technology to delete RelA from aortic cells. Tamoxifen-inducible, Col1a2-promoter driven Cre mice (Col1a2-Cre) were crossed with mT/mG Cre-reporter mice to determine which aortic cells undergo genetic recombination after Cre activation. Flow cytometry analysis of the aortic wall indicated that 88% of the genetically recombined cells were SMCs and 8% were fibroblasts. Next, RelA floxed (RelA f/f) mice, generated in our lab, were crossed with Col1a2-Cre mice. RelA f/f Cre+ and RelA f/f Cre- were stimulated with tamoxifen for 10 days to generate aortic-RelA deficient (Ao-RelA-/-) or wild-type (Ao-RelA+/+) transgenics. Flow cytometry, qRT-PCR, and immunohistochemistry analysis suggested a depletion of aortic-RelA greater than 60%. To test the role of Ao-RelA in AAD, Ao-RelA -/- (n= 20) and Ao-RelA +/+ (n=14) mice were infused with angiotensin II for 7 days. Surprisingly, 20% of Ao-RelA-/- mice died from development of AAD and aortic rupture while no deaths were observed in Ao-RelA+/+ group. In addition, 40% of Ao-RelA-/- mice developed AAD compared to 14% of Ao-RelA+/+ mice. There was no significant difference in TUNEL staining or ERTR7+ fibroblast population between the two groups. Conclusion: Our studies suggest that aortic wall-RelA may be necessary for protection from AAD.

Abstract 487: Systemic Administration of Target-Seeking, Vessel Penetrating Recombinant Decorin Fusion Protein, Car-DCN, Reduces Severity of Abdominal Aortic Aneurysm in Mice

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Yue (Steve) Shen ◽  
Valerio Russo ◽  
Matthew Zeglinski ◽  
Stephanie Sellers ◽  
Zhengguo Wu ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Fusion Protein ◽  
Vessel Wall ◽  
C Terminus ◽  
Abdominal Aortic ◽  
Homing Peptide ◽  
Apoe Ko Mice ◽  
Dependent Mechanism

Objective: Decorin (DCN) is a small leucine-rich proteoglycan that mediates collagen fibrollogenesis, organization, and tensile strength. DCN is reduced in abdominal aortic aneurysm (AAA) through a Granzyme B-dependent mechanism resulting in vessel wall instability and aneurysm formation. A recombinant decorin fusion protein CAR-DCN was engineered with an extended C-terminus comprised of CAR homing peptide that recognizes inflammatory blood vessels and penetrates deep into the vessel wall. In the present study, we sought to evaluate the role of systemically administered CAR-DCN in AAA progression and rupture rate in a murine model. Approach and Results: To induce aneurysm, apolipoprotein E knockout (ApoE-KO) mice were infused with 28 days of angiotensin II (AngII). CAR-DCN or vehicle was systemically administrated until day 15. We observed a significant increase in the survival of CAR-DCN-treated mice (93%) compared to vehicle controls (60%). Although the incidence of AAA onset was similar between vehicle and CAR-DCN groups, the severity of aneurysm in the CAR-DCN group was significantly reduced. Furthermore, histological analysis revealed that CAR-DCN treatment significantly increased DCN and collagen levels in aortic walls compares to vehicle controls. Conclusions: CAR-DCN administration attenuated the severity of Ang II-induced AAA in mice by reinforcing the vessel wall. CAR-DCN may represent a novel therapeutic strategy to attenuate AAA progression and rupture.

scholarly journals Long-Noncoding RNA (lncRNA) in the Regulation of Hypoxia-Inducible Factor (HIF) in Cancer

2020 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Dominik A. Barth ◽  
Felix Prinz ◽  
Julia Teppan ◽  
Katharina Jonas ◽  
Christiane Klec ◽  
...  
Keyword(s):  
Noncoding Rna ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Protein Coding ◽  
Rna Molecules ◽  
Von Hippel Lindau ◽  
Hypoxic Conditions ◽  
Main Regulator ◽  
Upstream Regulators

Hypoxia is dangerous for oxygen-dependent cells, therefore, physiological adaption to cellular hypoxic conditions is essential. The transcription factor hypoxia-inducible factor (HIF) is the main regulator of hypoxic metabolic adaption reducing oxygen consumption and is regulated by gradual von Hippel-Lindau (VHL)-dependent proteasomal degradation. Beyond physiology, hypoxia is frequently encountered within solid tumors and first drugs are in clinical trials to tackle this pathway in cancer. Besides hypoxia, cancer cells may promote HIF expression under normoxic conditions by altering various upstream regulators, cumulating in HIF upregulation and enhanced glycolysis and angiogenesis, altogether promoting tumor proliferation and progression. Therefore, understanding the underlying molecular mechanisms is crucial to discover potential future therapeutic targets to evolve cancer therapy. Long non-coding RNAs (lncRNA) are a class of non-protein coding RNA molecules with a length of over 200 nucleotides. They participate in cancer development and progression and might act as either oncogenic or tumor suppressive factors. Additionally, a growing body of evidence supports the role of lncRNAs in the hypoxic and normoxic regulation of HIF and its subunits HIF-1α and HIF-2α in cancer. This review provides a comprehensive update and overview of lncRNAs as regulators of HIFs expression and activation and discusses and highlights potential involved pathways.

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