| 1. |
- Berglund, Lisa, et al.
(author)
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NFAT regulates the expression of AIF-1 and IRT-1: Yin and yang splice variants of neointima formation and atherosclerosis.
- 2012
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 1755-3245 .- 0008-6363. ; 93, s. 414-423
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Journal article (peer-reviewed)abstract
- Aims Alternative transcription and splicing of the allograft inflammatory factor-1 (AIF-1) gene results in the expression of two different proteins: AIF-1 and interferon responsive transcript-1 (IRT-1). Here we explore the impact of AIF-1 and IRT-1 on vascular smooth muscle cell (VSMC) activation and neointima formation, the mechanisms underlying their alternative splicing, and associations of AIF-1 and IRT-1 mRNA with parameters defining human atherosclerotic plaque phenotype.Methods and results Translation of AIF-1 and IRT-1 results in different products with contrasting cellular distribution and functions. Overexpression of AIF-1 stimulates migration and proliferation of human VSMCs, whereas IRT-1 exerts opposite effects. Adenoviral infection of angioplasty-injured rat carotid arteries with AdAIF-1 exacerbates intima hyperplasia, whereas infection with AdIRT-1 reduces neointima. Expression of these variants is modulated by changes in nuclear factor of activated T-cells (NFAT) activity. Pharmacological inhibition of NFAT or targeting of NFATc3 with siRNA lowers the AIF-1/IRT-1 ratio and favors an anti-proliferative outcome. NFAT acts as a repressor on the IRT-1 transcriptional start site, which is also sensitive to interferon-γ stimulation. Expression of AIF-1 mRNA in human carotid plaques associates with less extracellular matrix and a more pro-inflammatory plaque and plasma profile, features that may predispose to plaque rupture. In contrast, expression of IRT-1 mRNA associates with a less aggressive phenotype and less VSMCs at the most stenotic region of the plaque.Conclusions Inhibition of NFAT signaling, by shifting the AIF-1/IRT-1 ratio, may be an attractive target to regulate the VSMC response to injury and manipulate plaque stability in atherosclerosis.
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| 2. |
- Bhattachariya, Anirban, et al.
(author)
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Expression of microRNAs is essential for arterial myogenic tone and pressure-induced activation of the PI3-kinase/Akt pathway.
- 2014
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 1755-3245 .- 0008-6363. ; 101:2, s. 288-296
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Journal article (peer-reviewed)abstract
- The myogenic response is the intrinsic ability of small arteries to constrict in response to increased intraluminal pressure. Although microRNAs have been shown to play a role in vascular smooth muscle function, their importance in the regulation of the myogenic response is not known. In this study, we investigate the role of microRNAs in the regulation of myogenic tone by using smooth muscle-specific and tamoxifen-inducible deletion of the endonuclease Dicer in mice.
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| 3. |
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| 4. |
- Bäck, Magnus, et al.
(author)
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Biomechanical factors in the biology of aortic wall and aortic valve diseases
- 2013
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In: Cardiovascular Research. - : Oxford University Press. - 0008-6363 .- 1755-3245. ; 99:2, s. 232-241
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Research review (peer-reviewed)abstract
- The biomechanical factors that result from the haemodynamic load on the cardiovascular system are a common denominator of several vascular pathologies. Thickening and calcification of the aortic valve will lead to reduced opening and the development of left ventricular outflow obstruction, referred to as aortic valve stenosis. The most common pathology of the aorta is the formation of an aneurysm, morphologically defined as a progressive dilatation of a vessel segment by more than 50% of its normal diameter. The aortic valve is exposed to both haemodynamic forces and structural leaflet deformation as it opens and closes with each heartbeat to assure unidirectional flow from the left ventricle to the aorta. The arterial pressure is translated into tension-dominated mechanical wall stress in the aorta. In addition, stress and strain are related through the aortic stiffness. Furthermore, blood flow over the valvular and vascular endothelial layer induces wall shear stress. Several pathophysiological processes of aortic valve stenosis and aortic aneurysms, such as macromolecule transport, gene expression alterations, cell death pathways, calcification, inflammation, and neoangiogenesis directly depend on biomechanical factors.
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| 5. |
- Carlström, Mattias, 1941-, et al.
(author)
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Dietary nitrate attenuates oxidative stress, prevents cardiac and renal injuries, and reduces blood pressure in salt-induced hypertension
- 2011
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 89:3, s. 574-585
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Journal article (peer-reviewed)abstract
- Aims Reduced bioavailability of endogenous nitric oxide (NO) is a central pathophysiological event in hypertension and other cardiovascular diseases. Recently, it was demonstrated that inorganic nitrate from dietary sources is converted in vivo to form nitrite, NO, and other bioactive nitrogen oxides. We tested the hypothesis that dietary inorganic nitrate supplementation may have therapeutic effects in a model of renal and cardiovascular disease. Methods and results Sprague-Dawley rats subjected to unilateral nephrectomy and chronic high-salt diet from 3 weeks of age developed hypertension, cardiac hypertrophy and fibrosis, proteinuria, and histological as well as biochemical signs of renal damage and oxidative stress. Simultaneous nitrate treatment (0.1 or 1 mmol nitrate kg(-1) day(-1)), with the lower dose resembling the nitrate content of a diet rich in vegetables, attenuated hypertension dose-dependently with no signs of tolerance. Nitrate treatment almost completely prevented proteinuria and histological signs of renal injury, and the cardiac hypertrophy and fibrosis were attenuated. Mechanistically, dietary nitrate restored the tissue levels of bioactive nitrogen oxides and reduced the levels of oxidative stress markers in plasma (malondialdehyde) and urine (Class VI F2-isoprostanes and 8-hydroxy-2-deoxyguanosine). In addition, the increased circulating and urinary levels of dimethylarginines (ADMA and SDMA) in the hypertensive rats were normalized by nitrate supplementation. Conclusion Dietary inorganic nitrate is strongly protective in this model of renal and cardiovascular disease. Future studies will reveal if nitrate contributes to the well-known cardioprotective effects of a diet rich in vegetables.
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| 6. |
- Dalin, Martin, 1982, et al.
(author)
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Myocardial KRASG12D expression does not cause cardiomyopathy in mice
- 2014
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 101:2, s. 229-235
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Journal article (peer-reviewed)abstract
- AimsGerm-line mutations in genes encoding components of the RAS/mitogen-activated protein kinase (MAPK) pathway cause developmental disorders called RASopathies. Hypertrophic cardiomyopathy (HCM) is the most common myocardial pathology and a leading cause of death in RASopathy patients. KRAS mutations are found in Noonan and cardio-facio-cutaneous syndromes. KRAS mutations, unlike mutations of RAF1 and HRAS, are rarely associated with HCM. This has been attributed to the fact that germ-line KRAS mutations cause only a moderate up-regulation of the MAPK pathway. Highly bioactive KRAS mutations have been hypothesized to cause severe cardiomyopathy incompatible with life. The aim of this study was to define the impact of KRASG12D expression in the heart.Methods and resultsTo generate mice with endogenous cardiomyocyte-specific KRASG12D expression (cKRASG12D mice), we bred mice with a Cre-inducible allele expressing KRASG12D from its endogenous promoter (Kras2LSL) to mice expressing Cre under control of the cardiomyocyte-specific α-myosin heavy chain promoter (αMHC-Cre). cKRASG12D mice showed high levels of myocardial ERK and AKT signalling. However, surprisingly, cKRASG12D mice were born in Mendelian ratios, appeared healthy, and had normal function, size, and histology of the heart.ConclusionMice with cardiomyocyte-specific KRAS G12D expression do not develop heart pathology. These results challenge the view that the level of MAPK activation correlates with the severity of HCM in RASopathies and suggests that MAPK-independent strategies may be of interest in the development of new treatments for these syndromes. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2013.
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| 7. |
- Danielsson, Christian, et al.
(author)
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Exploration of human, rat, and rabbit embryonic cardiomyocytes suggests K-channel block as a common teratogenic mechanism
- 2013
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In: Cardiovascular Research. - : Oxford University Press (OUP): Policy B. - 0008-6363 .- 1755-3245. ; 97:1, s. 23-32
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Journal article (peer-reviewed)abstract
- Several drugs blocking the rapidly activating potassium (K-r) channel cause malformations (including cardiac defects) and embryonic death in animal teratology studies. In humans, these drugs have an established risk for acquired long-QT syndrome and arrhythmia. Recently, associations between cardiac defects and spontaneous abortions have been reported for drugs widely used in pregnancy (e.g. antidepressants), with long-QT syndrome risk. To investigate whether a common embryonic adverse-effect mechanism exists in the human, rat, and rabbit embryos, we made a comparative study of embryonic cardiomyocytes from all three species. less thanbrgreater than less thanbrgreater thanPatch-clamp and quantitative-mRNA measurements of K-r and slowly activating K (K-s) channels were performed on human, rat, and rabbit primary cardiomyocytes and cardiac samples from different embryo-foetal stages. The K-r channel was present when the heart started to beat in all species, but was, in contrast to human and rabbit, lost in rats in late organogenesis. The specific K-r-channel blocker E-4031 prolonged the action potential in a species- and development-dependent fashion, consistent with the observed K-r-channel expression pattern and reported sensitive periods of developmental toxicity. E-4031 also increased the QT interval and induced 2:1 atrio-ventricular block in multi-electrode array electrographic recordings of rat embryos. The K-s channel was expressed in human and rat throughout the embryo-foetal period but not in rabbit. less thanbrgreater than less thanbrgreater thanThis first comparison of mRNA expression, potassium currents, and action-potential characteristics, with and without a specific K-r-channel blocker in human, rat, and rabbit embryos provides evidence of K-r-channel inhibition as a common mechanism for embryonic malformations and death.
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| 8. |
- Dantuma, NP, et al.
(author)
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Stressing the ubiquitin-proteasome system
- 2010
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In: Cardiovascular research. - : Oxford University Press (OUP). - 1755-3245 .- 0008-6363. ; 85:2, s. 263-271
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Journal article (peer-reviewed)
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| 9. |
- Dunér, Pontus, et al.
(author)
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Immunization of apoE-/- mice with aldehyde-modified fibronectin inhibits the development of atherosclerosis.
- 2011
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 1755-3245 .- 0008-6363. ; 91, s. 528-536
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Journal article (peer-reviewed)abstract
- Aims. Oxidation of LDL in the extracellular matrix of the arterial wall results in formation of malondialdehyde (MDA) that modifies surrounding matrix proteins. This is associated with activation of an immune response against modified extracellular matrix proteins present in atherosclerotic plaques. Clinical studies have revealed an inverse association between antibodies to MDA-modified fibronectin and risk for development of cardiovascular events. To determine the functional role of these immune responses in atherosclerosis we performed studies in which apoE-deficient mice were immunized with MDA-modified fibronectin. Methods and Results. Immunization of apoE-deficient mice with MDA-modified fibronectin resulted in a 70% decrease in plaque area and a less inflammatory phenotype of remaining plaques. Immunization shifted a weak naturally occurring Th1 antibody response against MDA-fibronectin into a Th2 antibody response. Cytokine expression and flow cytometry analyses of spleen cells from immunized mice showed an activation of regulatory T cells. Immunization with MDA-fibronectin was also found to reduce plasma fibronectin levels. Conclusions. Immunization with MDA-fibronectin significantly reduces the development of atherosclerosis in apoE-deficient mice suggesting that the immune response observed in humans may have a protective effect. MDA-fibronectin represents a possible novel target for immunomodulatory therapy in atherosclerosis.
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