Abstract 108: Deletion of Lrp1 In SMCS Differentially Alters Susceptibility of Distinct Vascular Beds to BAPN-Induced Aneurysm and Dissection Formation

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Areck A Ucuzian ◽  
Selen C Catania ◽  
Subhradip Mukhopadhyay ◽  
Rajabrata Sarkar ◽  
Dudley S Strickland
Keyword(s):  
Structural Integrity ◽  
Lysyl Oxidase ◽  
Ldl Receptor ◽  
Wild Type ◽  
Radiographic Evidence ◽  
Iliac Arteries ◽  
Aortic Aneurysm And Dissection ◽  
Genetic Deletion ◽  
Vascular Beds

Lysyl oxidase (LOX) inhibition by β-aminopropionitrile (BAPN) induces aortic aneurysm and dissection (AD). The LDL receptor-related protein 1 (LRP1) is an endocytic receptor that plays a key role in maintaining the structural integrity of vessels. Deletion of LRP1 in vascular smooth muscle cells (smLRP1 -/-) in mice induces fully penetrant and spontaneous aneurysms with aging. The objective of this study was to investigate the role of smLRP1 in modulating the susceptibility of various vascular beds to BAPN-induced AD. Wild-type (WT) and smLRP1 -/- mice were treated with BAPN supplemented in drinking water (3g/L). After 4-16 weeks, the vessels were analyzed histologically and with micro-CT. Abnormal elastic lamellae were identified throughout the vasculature of both the BAPN-treated WT and smLRP1 -/- cohorts. smLRP1 -/- mice were more susceptible to aneurysm formation after 8 (p=0.035) or 16 weeks (p=0.043) of treatment. Aneurysms in BAPN-treated WT mice were localized to the aorta, while aneurysms in BAPN-treated smLRP1 -/- mice were localized to the visceral and iliac arteries (Table). Histologic and radiographic evidence of AD was detected in the ascending and descending thoracic aorta in BAPN and AngII (subcutaneous,1μg/kg/min, 24 hrs)-treated WT mice, but not in BAPN and Ang II-treated smLRP1 -/- mice (Figure). Thoracic ruptures were more prevalent in the BAPN-treated WT group and abdominal ruptures were more prevalent in the BAPN-treated smLRP1 -/-group (p=0.02). In summary, these data demonstrate that genetic deletion of LRP1 in SMCs differentially alters the susceptibility of distinct vascular beds to the development of aneurysm and dissection upon LOX inhibition.

Abstract 10: The Matrix Crosslinking Enzyme Lysyl Oxidase Like-2 as a Target to Reverse Vascular Stiffness

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Jochen Steppan ◽  
Ivy Wang ◽  
Yehudit Bergman ◽  
Siqi Tan ◽  
Sandeep Jandu ◽  
...  
Keyword(s):  
Lysyl Oxidase ◽  
Vascular Stiffness ◽  
Matrix Composition ◽  
Wild Type ◽  
Matrix Deposition ◽  
Proteomic Approach ◽  
Vascular Stiffening ◽  
Group 2 ◽  
Novel Target

Introduction: Stiffening of the central vasculature is a strong and independent predictor of adverse cardiovascular events. Vascular stiffening is a complex process that involves changes in the vessel wall composition and smooth muscle cell (SMC) function. We recently used an unbiased proteomic approach to identify Lysyl oxidase like 2 (LOXL2) as a potential new target in vascular stiffness. The goal of this study is to characterize the role of LOXL2 in vascular stiffening and its potential as a target to reverse vascular stiffness associated with hypertension. Results: We demonstrate that decreased nitric oxide (NO) bioavailability results in increased secretion and activity of LOXL2 in SMCs. LOXL2 knockdown markedly attenuates SMC adhesion, motility, and proliferation and results in diminished matrix deposition. LOXL2 knockdown also results in striking changes in the stiffness and cytoskeletal remodeling events in CMSs. Tensile testing shows that intact aortas of LOXL2+/- animals are stiffer when compared with those from wild type mice, while there is no difference in decellularized vessels. We next investigated the role of LOXL2 in the development of hypertension using angiotensin II (AngII) infusion in LOXL2+/- (group 1) and wild type (WT; group 2) mice. BP and pulse wave velocity (PWV) increased significantly with AngII infusion in both groups during the study period, without a significant change in heart rate. Compared to WT animals, contractile responsiveness was markedly diminished in LOXL2+/- animals at baseline as well as with AngII infusion when compared with untreated controls. The NO- dependent vasodilatory response to acetylcholine was identical at baseline and diminished significantly with AngII infusion in both groups of animals. There was no difference between the groups in the endothelium-independent response to sodium nitroprusside. Conclusion: In this study, we demonstrated the role of NO in the regulation of LOXL2. Interestingly, LOXL2 appears to have a dual role in vascular stiffness by affecting both SMC function as well as matrix composition. We therefore conclude that LOXL2 is a novel target involved in vascular stiffness that requires further characterization to elicit the possibility of therapeutic intervention.

scholarly journals Interplay Between LOX Enzymes and Integrins in the Tumor Microenvironment

Cancers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 729 ◽  
Author(s):  
Pier Giorgio Amendola ◽  
Raphael Reuten ◽  
Janine Terra Erler
Keyword(s):  
Tumor Microenvironment ◽  
Structural Integrity ◽  
Lysyl Oxidase ◽  
Review Article ◽  
Amine Oxidases ◽  
Covalent Crosslinking ◽  
Cancer Types ◽  
Lox Inhibitors ◽  
Cell Phenotypes

Members of the lysyl oxidase (LOX) family are secreted copper-dependent amine oxidases that catalyze the covalent crosslinking of collagens and elastin in the extracellular matrix (ECM), an essential process for the structural integrity of all tissues. LOX enzymes can also remodel the tumor microenvironment and have been implicated in all stages of tumor initiation and progression of many cancer types. Changes in the ECM can influence several cancer cell phenotypes. Integrin adhesion complexes (IACs) physically connect cells with their microenvironment. This review article summarizes the main findings on the role of LOX proteins in modulating the tumor microenvironment, with a particular focus on how ECM changes are integrated by IACs to modulate cells behavior. Finally, we discuss how the development of selective LOX inhibitors may lead to novel and effective therapies in cancer treatment.

scholarly journals Modulation of flavocytochrome b2 intraprotein electron transfer via an interdomain hinge region

1996 ◽  
Vol 316 (2) ◽  
pp. 507-513 ◽  
Author(s):  
R. Eryl SHARP ◽  
Stephen K. CHAPMAN ◽  
Graeme A. REID
Keyword(s):  
Electron Transfer ◽  
Steady State ◽  
Lactate Dehydrogenase ◽  
Structural Integrity ◽  
Hinge Region ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Lactate Dehydrogenase Activity ◽  
Flavocytochrome B2

The two domains of flavocytochrome b2 are connected by a typical hinge peptide. To probe the role of the hinge in modulating the efficiency of intraprotein electron transfer between these two domains, a number of mutant enzymes with truncated hinge regions were previously constructed and characterized [Sharp, Chapman and Reid (1996) Biochemistry 35, 891–899]. In the present study two mutant enzymes with elongated hinge regions have been constructed (HI3 and HI6) to further our understanding of the controlling influence of hinge length and primary structure on intraprotein electron transfer. Modification of the hinge had little effect on the lactate dehydrogenase activity of the enzyme, as was evident from steady-state experiments using ferricyanide as electron acceptor and from pre-steady-state experiments monitoring flavin reduction. However, the hinge insertions lowered the enzyme's effectiveness as a cytochrome c reductase. This effect results from a defect at the first interdomain electron-transfer step (FMNH2 → haem electron transfer), where the rate constants for haem reduction in HI3 and HI6 were 50-and 100-fold lower than the corresponding value for the wild-type enzyme. Preservation of structural integrity within the hinge region is apparently essential for efficient intraprotein electron transfer.

Role of PAR2 in murine pulmonary pseudomonal infection

2008 ◽  
Vol 294 (2) ◽  
pp. L368-L377 ◽  
Author(s):  
Theo J. Moraes ◽  
Raiza Martin ◽  
Jonathan D. Plumb ◽  
Eric Vachon ◽  
Cheryl M. Cameron ◽  
...  
Keyword(s):  
Lung Inflammation ◽  
Lavage Fluid ◽  
Wild Type ◽  
Protease Activated Receptors ◽  
Tnf Α ◽  
Pulmonary Inflammatory Response ◽  
Ifn Γ ◽  
Genetic Deletion

Proteinases can influence lung inflammation by various mechanisms, including via cleavage and activation of protease-activated receptors (PAR) such as PAR2. In addition, proteinases such as neutrophil and/or Pseudomonas-derived elastase can disarm PAR2 resulting in loss of PAR2 signaling. Currently, the role of PAR2 in host defense against bacterial infection is not known. Using a murine model of acute Pseudomonas aeruginosa pneumonia, we examined differences in the pulmonary inflammatory response between wild-type and PAR2−/−mice. Compared with wild-type mice, PAR2−/−mice displayed more severe lung inflammation and injury in response to P. aeruginosa infection as indicated by higher bronchoalveolar lavage fluid neutrophil numbers, protein concentration, and TNF-α levels. By contrast, IFN-γ levels were markedly reduced in PAR2−/−compared with wild-type mice. Importantly, clearance of P. aeruginosa was diminished in PAR2−/−mice. In vitro testing revealed that PAR2−/−neutrophils killed significantly less bacteria than wild-type murine neutrophils. Further, both neutrophils and macrophages from PAR2−/−mice displayed significantly reduced phagocytic efficiency compared with wild-type phagocytes. Stimulation of PAR2 on macrophages using a PAR2-activating peptide resulted in enhanced phagocytosis directly implicating PAR2 signaling in the phagocytic process. We conclude that genetic deletion of PAR2 is associated with decreased clearance of P. aeruginosa. Our data suggest that a deficiency in IFN-γ production and impaired bacterial phagocytosis are two potential mechanisms responsible for this defect.

scholarly journals Role of Nox isoforms in angiotensin II-induced oxidative stress and endothelial dysfunction in brain

2012 ◽  
Vol 113 (2) ◽  
pp. 184-191 ◽  
Author(s):  
Sophocles Chrissobolis ◽  
Botond Banfi ◽  
Christopher G. Sobey ◽  
Frank M. Faraci
Keyword(s):  
Oxidative Stress ◽  
Angiotensin Ii ◽  
Endothelial Dysfunction ◽  
Minor Role ◽  
Oxygen Species ◽  
Ang Ii ◽  
Wild Type ◽  
Vascular Beds ◽  
A Minor

Angiotensin II (Ang II) promotes vascular disease through several mechanisms including by producing oxidative stress and endothelial dysfunction. Although multiple potential sources of reactive oxygen species exist, the relative importance of each is unclear, particularly in individual vascular beds. In these experiments, we examined the role of NADPH oxidase (Nox1 and Nox2) in Ang II-induced endothelial dysfunction in the cerebral circulation. Treatment with Ang II (1.4 mg·kg−1·day−1 for 7 days), but not vehicle, increased blood pressure in all groups. In wild-type (WT; C57Bl/6) mice, Ang II reduced dilation of the basilar artery to the endothelium-dependent agonist acetylcholine compared with vehicle but had no effect on responses in Nox2-deficient (Nox2−/y) mice. Ang II impaired responses to acetylcholine in Nox1 WT (Nox1+/y) and caused a small reduction in responses to acetylcholine in Nox1-deficient (Nox1−/y) mice. Ang II did not impair responses to the endothelium-independent agonists nitroprusside or papaverine in either group. In WT mice, Ang II increased basal and phorbol-dibutyrate-stimulated superoxide production in the cerebrovasculature, and these increases were abolished in Nox2−/y mice. Overall, these data suggest that Nox2 plays a relatively prominent role in mediating Ang II-induced oxidative stress and cerebral endothelial dysfunction, with a minor role for Nox1.

scholarly journals Global genetic deletion of CaV3.3 channels facilitates anaesthetic induction and enhances isoflurane-sparing effects of T-type calcium channel blockers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Simon Feseha ◽  
Tamara Timic Stamenic ◽  
Damon Wallace ◽  
Caesare Tamag ◽  
Lingling Yang ◽  
...  
Keyword(s):  
Channel Blocker ◽  
Mutant Mice ◽  
Channel Blockers ◽  
Volatile Anaesthetics ◽  
Wild Type ◽  
Anaesthetic Induction ◽  
Knock Out ◽  
Valuable Adjunct ◽  
Genetic Deletion

AbstractWe previously documented that the CaV3.3 isoform of T-type calcium channels (T-channels) is inhibited by clinically relevant concentrations of volatile anaesthetics, including isoflurane. However, little is understood about the functional role of CaV3.3 channels in anaesthetic-induced hypnosis and underlying neuronal oscillations. To address this issue, we used CaV3.3 knock-out (KO) mice and a panselective T-channel blocker 3,5-dichloro-N-[1-(2,2-dimethyltetrahydro-pyran-4-ylmethyl)-4-fluoro-piperidin-4-ylmethyl]-benzamide (TTA-P2). We found that mutant mice injected with the vehicle showed faster induction of hypnosis than wild-type (WT) mice, while the percent isoflurane at which hypnosis and immobility occurred was not different between two genotypes. Furthermore, we found that TTA-P2 facilitated isoflurane induction of hypnosis in the CaV3.3 KO mice more robustly than in the WT mice. Isoflurane-induced hypnosis following injections of TTA-P2 was accompanied with more prominent delta and theta EEG oscillations in the mutant mice, and reached burst-suppression pattern earlier when compared to the WT mice. Our findings point to a relatively specific value of CaV3.3 channels in anaesthetic induced hypnosis. Furthermore, we propose that T-channel blockers may be further explored as a valuable adjunct to reducing the usage of potent volatile anaesthetics, thereby improving their safety.

Differential Role of Components of the Fibrinolytic System in the Formation and Removal of Thrombus Induced by Endothelial Injury

1999 ◽  
Vol 81 (04) ◽  
pp. 601-604 ◽  
Author(s):  
Hiroyuki Matsuno ◽  
Osamu Kozawa ◽  
Masayuki Niwa ◽  
Shigeru Ueshima ◽  
Osamu Matsuo ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Thrombus Formation ◽  
Endothelial Injury ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
Clot Lysis ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Pai 1

SummaryThe role of fibrinolytic system components in thrombus formation and removal in vivo was investigated in groups of six mice deficient in urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), or plasminogen activator inhibitor-1 (PAI-1) (u-PA-/-, t-PA-/- or PAI-1-/-, respectively) or of their wild type controls (u-PA+/+, t-PA+/+ or PAI-1+/+). Thrombus was induced in the murine carotid artery by endothelial injury using the photochemical reaction between rose bengal and green light (540 nm). Blood flow was continuously monitored for 90 min on day 0 and for 20 min on days 1, 2 and 3. The times to occlusion after the initiation of endothelial injury in u-PA+/+, t-PA+/+ or PAI-1+/+ mice were 9.4 ± 1.3, 9.8 ± 1.1 or 9.7 ± 1.6 min, respectively. u-PA-/- and t-PA-/- mice were indistinguishable from controls, whereas that of PAI-1-/- mice were significantly prolonged (18.4 ± 3.7 min). Occlusion persisted for the initial 90 min observation period in 10 of 18 wild type mice and was followed by cyclic reflow and reocclusion in the remaining 8 mice. At day 1, persistent occlusion was observed in 1 wild type mouse, 8 mice had cyclic reflow and reocclusion and 9 mice had persistent reflow. At day 2, all injured arteries had persistent reflow. Persistent occlusion for 90 min on day 0 was observed in 3 u-PA-/-, in all t-PA-/- mice at day 1 and in 2 of the t-PA-/-mice at day 2 (p <0.01 versus wild type mice). Persistent patency was observed in all PAI-1-/- mice at day 1 and in 5 of the 6 u-PA-/- mice at day 2 (both p <0.05 versus wild type mice). In conclusion, t-PA increases the rate of clot lysis after endothelial injury, PAI-1 reduces the time to occlusion and delays clot lysis, whereas u-PA has little effect on thrombus formation and spontaneous lysis.

scholarly journals Salicylic Acid Accumulation Controlled by LSD1 Is Essential in Triggering Cell Death in Response to Abiotic Stress

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 962
Author(s):  
Maciej Jerzy Bernacki ◽  
Anna Rusaczonek ◽  
Weronika Czarnocka ◽  
Stanisław Karpiński
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Abiotic Stress ◽  
Wild Type ◽  
Pr Genes ◽  
Genes Expression ◽  
Salicylic Acid Accumulation ◽  
Cell Death Phenotype ◽  
Insight Into

Salicylic acid (SA) is well known hormonal molecule involved in cell death regulation. In response to a broad range of environmental factors (e.g., high light, UV, pathogens attack), plants accumulate SA, which participates in cell death induction and spread in some foliar cells. LESION SIMULATING DISEASE 1 (LSD1) is one of the best-known cell death regulators in Arabidopsis thaliana. The lsd1 mutant, lacking functional LSD1 protein, accumulates SA and is conditionally susceptible to many biotic and abiotic stresses. In order to get more insight into the role of LSD1-dependent regulation of SA accumulation during cell death, we crossed the lsd1 with the sid2 mutant, caring mutation in ISOCHORISMATE SYNTHASE 1(ICS1) gene and having deregulated SA synthesis, and with plants expressing the bacterial nahG gene and thus decomposing SA to catechol. In response to UV A+B irradiation, the lsd1 mutant exhibited clear cell death phenotype, which was reversed in lsd1/sid2 and lsd1/NahG plants. The expression of PR-genes and the H2O2 content in UV-treated lsd1 were significantly higher when compared with the wild type. In contrast, lsd1/sid2 and lsd1/NahG plants demonstrated comparability with the wild-type level of PR-genes expression and H2O2. Our results demonstrate that SA accumulation is crucial for triggering cell death in lsd1, while the reduction of excessive SA accumulation may lead to a greater tolerance toward abiotic stress.

scholarly journals The Prognostic and Predictive Role of Somatic BRCA Mutations in Ovarian Cancer: Results from a Multicenter Cohort Study

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 565
Author(s):  
Angela Toss ◽  
Claudia Piombino ◽  
Elena Tenedini ◽  
Alessandra Bologna ◽  
Elisa Gasparini ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Positive Impact ◽  
Progression Free Survival ◽  
Molecular Testing ◽  
Wild Type ◽  
Brca Mutations ◽  
Multicenter Cohort Study ◽  
Advanced Stages ◽  
Predictive Role

Previous research involving epithelial ovarian cancer patients showed that, compared to germline BRCA (gBRCA) mutations, somatic BRCA (sBRCA) mutations present a similar positive impact with regard to overall survival (OS) and platinum and PARP (poly (ADP-ribose) polymerase) inhibitor sensitivity. Nevertheless, molecular testing in these studies did not include copy number variation (CNV) analyses of BRCA genes. The aim of this study was to explore the prognostic and predictive role of sBRCA mutations as compared to gBRCA mutations in patients who were also tested for CNVs. Among the 158 patients included in the study, 17.09% of patients carried a pathogenic or likely pathogenic gBRCA variant and 15.19% of patients presented pathogenetic or likely pathogenic sBRCA variants and/or CNVs. Overall, 81.6% of the patients included in this study were diagnosed with a serous histotype, and 77.2% were in advanced stages. Among women diagnosed in advanced stages, gBRCA patients showed better progression-free survival and OS as compared to sBRCA and wild-type patients, whereas sBRCA patients did not show any advantage in outcome as compared to wild-type patients. In this study, the introduction of CNV analyses increased the detection rate of sBRCA mutations, and the resulting classification among gBRCA, sBRCA and wild-type patients was able to properly stratify the prognosis of OC patients. Particularly, sBRCA mutation patients failed to show any outcome advantage as compared to wild-type patients.

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