Subtopic Deep Dive
Urotensin II and Endothelial Dysfunction
Research Guide
What is Urotensin II and Endothelial Dysfunction?
Urotensin II (U-II) is a potent vasoactive peptide that impairs endothelial nitric oxide production, contributing to endothelial dysfunction and atherosclerosis progression through RhoA/Rho-kinase and NADPH oxidase activation.
U-II binds its receptor UT (GPR14), inducing RhoA activation and smooth muscle contraction (Sauzeau et al., 2001, 259 citations). Studies show upregulated U-II and UT expression in human aortic atherosclerotic lesions (Bousette et al., 2004, 128 citations). Human U-II activates NADPH oxidase in pulmonary artery cells, linking it to oxidative stress (Djordjevic et al., 2004, 162 citations).
Why It Matters
U-II overexpression in atherosclerosis promotes vascular inflammation and plaque formation, as evidenced by increased expression in aortic lesions (Bousette et al., 2004). This pathway intersects with opposing apelin signaling that antagonizes angiotensin II effects in mouse atherosclerosis models (Chun et al., 2008). Targeting U-II could mitigate endothelial dysfunction in cardiovascular diseases, with Rho-kinase inhibitors like Y-27632 blocking U-II-induced contraction (Sauzeau et al., 2001). Maguire and Davenport (2002) highlight U-II's potency rivaling endothelin in vasoconstriction.
Key Research Challenges
Linking U-II to NO Impairment
Mechanisms by which U-II reduces endothelial nitric oxide bioavailability remain unclear. Studies focus on RhoA/Rho-kinase mediation in smooth muscle but lack direct endothelial models (Sauzeau et al., 2001). NADPH oxidase activation by U-II generates oxidative stress that may quench NO (Djordjevic et al., 2004).
U-II Expression in Atherosclerosis
Quantifying U-II and UT upregulation in human plaques requires advanced imaging (Bousette et al., 2004). Variability in small vs. large coronary artery responses complicates translation (Maguire et al., 2004). No longitudinal studies track U-II levels with plaque progression.
Therapeutic Targeting of UT Receptor
Developing selective UT antagonists faces challenges from U-II's structural similarity to endothelin (Maguire and Davenport, 2002). Vaudry et al. (2014) detail receptor pharmacology but clinical trials are absent. Interactions with apelin-APJ pathways need dissection (Chun et al., 2008).
Essential Papers
Apelin signaling antagonizes Ang II effects in mouse models of atherosclerosis
Hyung J. Chun, Ziad A. Ali, Yoko Kojima et al. · 2008 · Journal of Clinical Investigation · 324 citations
Apelin and its cognate G protein-coupled receptor APJ constitute a signaling pathway with a positive inotropic effect on cardiac function and a vasodepressor function in the systemic circulation. T...
Human Urotensin II–Induced Contraction and Arterial Smooth Muscle Cell Proliferation Are Mediated by RhoA and Rho-Kinase
Vincent Sauzeau, Erik Le Mellionnec, Jacques Bertoglio et al. · 2001 · Circulation Research · 259 citations
The aim of this work was to investigate the coupling of human urotensin II (hU-II) to RhoA activation and regulation of RhoA-dependent functions. The use of the Rho-kinase inhibitor Y-27632 and the...
Endothelial dysfunction in the regulation of cirrhosis and portal hypertension
Yasuko Iwakiri · 2011 · Liver International · 190 citations
Abstract Portal hypertension is caused by an increased intrahepatic resistance, a major consequence of cirrhosis. Endothelial dysfunction in liver sinusoidal endothelial cells (LSECs) decreases the...
Human Urotensin II Is a Novel Activator of NADPH Oxidase in Human Pulmonary Artery Smooth Muscle Cells
Talija Djordjevic, Rachida S. BelAiba, Steve Bonello et al. · 2004 · Arteriosclerosis Thrombosis and Vascular Biology · 162 citations
Background— Human urotensin II (hU-II) is a potent vasoactive peptide possibly involved in pulmonary hypertension. Because the signaling mechanisms activated by this peptide in the pulmonary vascul...
Pathophysiology of isoprostanes in the cardiovascular system: implications of isoprostane‐mediated thromboxane<scp>A</scp><sub>2</sub>receptor activation
Jochen Bauer, Anne Ripperger, Stefan Frantz et al. · 2014 · British Journal of Pharmacology · 147 citations
Isoprostanes are free radical‐catalysed PG ‐like products of unsaturated fatty acids, such as arachidonic acid, which are widely recognized as reliable markers of systemic lipid peroxidation and ox...
Is urotensin‐II the new endothelin?
Janet J. Maguire, Anthony P. Davenport · 2002 · British Journal of Pharmacology · 130 citations
Urotensin‐II (U‐II), a peptide isolated from the urophysis of teleost fish 35 years ago, is the endogenous ligand of the mammalian orphan receptor GPR14/SENR. Recently, human homologues of both the...
Increased expression of urotensin II and its cognate receptor GPR14 in atherosclerotic lesions of the human aorta
Nicolas Bousette, Lisa Patel, Stephen A. Douglas et al. · 2004 · Atherosclerosis · 128 citations
Reading Guide
Foundational Papers
Start with Sauzeau et al. (2001, 259 citations) for RhoA mechanisms and Chun et al. (2008, 324 citations) for atherosclerosis context, as they establish core signaling and disease relevance.
Recent Advances
Vaudry et al. (2014, 100 citations) for comprehensive UT receptor review; Pitkin et al. (2010, 105 citations) on apelin modulation in human disease.
Core Methods
Rho-kinase inhibition (Y-27632), immunohistochemistry for U-II/UT in tissues, NADPH oxidase assays in smooth muscle cells, mouse atherosclerosis models with Ang II infusion.
How PapersFlow Helps You Research Urotensin II and Endothelial Dysfunction
Discover & Search
Research Agent uses citationGraph on Sauzeau et al. (2001, 259 citations) to map RhoA/U-II papers, exaSearch for 'urotensin II endothelial nitric oxide' retrieves Bousette et al. (2004), and findSimilarPapers uncovers Djordjevic et al. (2004) NADPH oxidase links.
Analyze & Verify
Analysis Agent applies readPaperContent to extract Rho-kinase inhibitor data from Sauzeau et al. (2001), verifyResponse with CoVe checks U-II atherosclerosis claims against Bousette et al. (2004), and runPythonAnalysis performs statistical meta-analysis of citation networks with GRADE grading for evidence strength.
Synthesize & Write
Synthesis Agent detects gaps in U-II-endothelial NO mechanisms via contradiction flagging across Maguire et al. (2004) and Chun et al. (2008); Writing Agent uses latexEditText for figure legends, latexSyncCitations for 10+ references, and latexCompile to generate review sections with exportMermaid for U-II signaling diagrams.
Use Cases
"Extract dose-response data from U-II RhoA papers and plot IC50 curves"
Research Agent → searchPapers 'urotensin II Rho-kinase Y-27632' → Analysis Agent → readPaperContent (Sauzeau 2001) → runPythonAnalysis (pandas/matplotlib IC50 curve fitting) → researcher gets publication-ready dose-response plot.
"Draft LaTeX review on U-II in atherosclerosis with citations"
Synthesis Agent → gap detection on Bousette (2004) + Maguire (2004) → Writing Agent → latexEditText (intro/methods) → latexSyncCitations (10 papers) → latexCompile → researcher gets PDF manuscript with synced bibliography.
"Find code for U-II NADPH oxidase simulations"
Research Agent → searchPapers 'urotensin II NADPH oxidase model' → paperExtractUrls (Djordjevic 2004) → paperFindGithubRepo → githubRepoInspect → researcher gets verified simulation code from related oxidative stress repos.
Automated Workflows
Deep Research workflow scans 50+ U-II papers via citationGraph from Chun et al. (2008), generating structured reports on endothelial links with GRADE scores. DeepScan's 7-step chain verifies U-II expression claims (Bousette 2004) using CoVe checkpoints and runPythonAnalysis for expression meta-data. Theorizer builds hypotheses on U-II vs. apelin antagonism from Maguire (2002) and Pitkin (2010).
Frequently Asked Questions
What defines Urotensin II's role in endothelial dysfunction?
U-II impairs nitric oxide production via RhoA/Rho-kinase and NADPH oxidase, promoting vasoconstriction and atherosclerosis (Sauzeau et al., 2001; Djordjevic et al., 2004).
What are key methods studying U-II signaling?
Rho-kinase inhibitor Y-27632 blocks U-II contraction; immunohistochemistry detects U-II in plaques; NADPH assays measure oxidase activity (Sauzeau et al., 2001; Bousette et al., 2004; Djordjevic et al., 2004).
What are foundational papers?
Sauzeau et al. (2001, 259 citations) on RhoA mediation; Chun et al. (2008, 324 citations) on apelin counteraction; Bousette et al. (2004, 128 citations) on plaque expression.
What open problems exist?
Direct endothelial U-II effects on NO synthase; clinical UT antagonists; interplay with isoprostanes in oxidative stress (Vaudry et al., 2014; Bauer et al., 2014).
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