| 1. |
- Smith, Gustav, et al.
(författare)
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Discovery of Genetic Variation on Chromosome 5q22 Associated with Mortality in Heart Failure
- 2016
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Failure of the human heart to maintain sufficient output of blood for the demands of the body, heart failure, is a common condition with high mortality even with modern therapeutic alternatives. To identify molecular determinants of mortality in patients with new-onset heart failure, we performed a meta-analysis of genome-wide association studies and follow-up genotyping in independent populations. We identified and replicated an association for a genetic variant on chromosome 5q22 with 36% increased risk of death in subjects with heart failure (rs9885413, P = 2.7x10-9). We provide evidence from reporter gene assays, computational predictions and epigenomic marks that this polymorphism increases activity of an enhancer region active in multiple human tissues. The polymorphism was further reproducibly associated with a DNA methylation signature in whole blood (P = 4.5x10-40) that also associated with allergic sensitization and expression in blood of the cytokine TSLP (P = 1.1x10-4). Knockdown of the transcription factor predicted to bind the enhancer region (NHLH1) in a human cell line (HEK293) expressing NHLH1 resulted in lower TSLP expression. In addition, we observed evidence of recent positive selection acting on the risk allele in populations of African descent. Our findings provide novel genetic leads to factors that influence mortality in patients with heart failure.
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| 2. |
- Gidlöf, Andreas C., et al.
(författare)
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Differences in retinol metabolism and proliferative response between neointimal and medial smooth muscle cells
- 2006
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1018-1172 .- 1423-0135. ; 43:4, s. 392-398
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Tidskriftsartikel (refereegranskat)abstract
- Vascular disease is multifactorial and smooth muscle cells (SMCs) play a key role. Retinoids have been shown to influence many disease-promoting processes including proliferation and differentiation in the vessel wall. Phenotypic heterogeneity of vascular SMCs is a well-known phenomenon and phenotypic modulation of SMCs precedes intimal hyperplasia. The SMCs that constitute the intimal hyperplasia demonstrate a distinct phenotype and differ in gene expression compared to medial SMCs. Cellular retinol-binding protein-1 (CRBP-I), involved in retinoid metabolism, is highly expressed in intimal SMCs, indicating altered retinoid metabolism in this subset of cells. The aim of this study was to evaluate the metabolism of all-trans ROH (atROH), the circulating prohormone to active retinoids, in vascular SMCs of different phenotypes. The results show an increased uptake of atROH in intimal SMCs compared to medial SMCs as well as increased expression of the retinoid-metabolizing enzymes retinol clehydrogenase-5 and retinal dehydrogenase-1 and, in conjunction with this gene expression, increased production of all-trans retinoic acid (atRA). Furthermore, the retinoic acid-catabolizing enzyme CYP26A1 is expressed at higher levels in medial SMCs compared to intimal SMCs. Thus, both retinoid activation and deactivation processes are in operation. To analyze if the difference in ROH metabolism was also correlated to differences in the biological response to retinol, the effects of ROH on proliferation of SMCs with this phenotypic heterogeneity were studied. We found that intimal SMCs showed a dose- and time-dependent growth inhibition when treated with atROH in contrast to medial SMCs, in which atROH had a mitogenic effect. This study shows, for the first time, that (1) vascular SMCs are able to synthesize biologically active atRA from the prohormone atROH, (2) intimal SMCs have a higher capacity to internalize atROH and metabolize atROH into atRA compared to medial SMCs and (3) atROH inhibits growth of intimal SMCs, but induces medial SMC growth.
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| 3. |
- Gidlöf, Andreas C., et al.
(författare)
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Increased retinoid signaling in vascular smooth muscle cells by proinflammatory cytokines
- 2001
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 286:2, s. 336-342
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Tidskriftsartikel (refereegranskat)abstract
- Retinoids have been shown to modulate inflammation and the immune response in many cell types including macrophages, endothelial cells, and vascular smooth muscle cells. However, present knowledge of whether inflammatory mediators modulate vitamin A status in these cells is limited. To identify the role of inflammation on retinoid metabolism in vascular smooth muscle cells, the cells were exposed to a combination of proinflammatory cytokines: interleukin-1beta, interferon-gamma, and lipopolysaccharides. Without stimulation with proinflammatory cytokines, vascular smooth muscle cells expressed retinol dehydrogenases-2 and 5 mRNA detected by RT-PCR. Stimulation with the combination of cytokines induced a substantial increase of retinol dehydrogenase-5 mRNA. This was associated with increased production of ligands for retinoic acid receptors, when assayed in a retinoic acid receptor-dependent luciferase reporter system. Our results demonstrate that inflammatory mediators activate the retinoid metabolic pathway in vascular smooth muscle cells, which potentially may modulate the inflammatory response in the vascular wall.
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| 4. |
- Gidlöf, Andreas C., et al.
(författare)
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Vitamin A : a drug for prevention of restenosis/reocclusion after percutaneous coronary intervention?
- 2008
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Ingår i: Clinical Science. - 0143-5221 .- 1470-8736. ; 114:1, s. 19-25
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Forskningsöversikt (refereegranskat)abstract
- The re-establishment of adequate blood flow in a vessel with a reduced lumen due to an atherosclerotic plaque by percutaneous vascular intervention is a well established procedure. However, the long-term outcome of such interventions is negatively influenced by the development of intimal hyperplasia/restenosis. Although extensively researched, this still represents a significant clinical problem. Retinoids, i.e. natural and synthetic derivates of vitamin A, represent a potential therapeutic compound, since they have been shown to influence the vast majority of processes that ultimately lead to reocclusion of the injured vessel. Retinoids exert their effects at the transcriptional level through their nuclear receptors. Targeting multiple processes, i.e. proliferation, migration, extracellular matrix composition and cell differentiation, as well as coagulation/fibrinolysis, should increase their future role in the prevention of restenosis. The purpose of this review is to summarize the diverse effects of retinoids on pathobiological and biological processes activated at sites of vascular injury with particular emphasis on intimal hyperplasia/restenosis after endovascular interventions.
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| 5. |
- Krivospitskaya, Olesya, 1983-, et al.
(författare)
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A CYP26B1 polymorphism enhances retinoic acid catabolism and may aggravate atherosclerosis
- 2012
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Ingår i: Molecular Medicine. - New York, USA : The Feinstein Institute for Medical Research. - 1076-1551 .- 1528-3658. ; 18:1, s. 712-718
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Tidskriftsartikel (refereegranskat)abstract
- All-trans retinoic acid, controlled by CYP26 enzymes, potentially has beneficial effects in atherosclerosis treatment. This study investigates CYP26B1 in atherosclerosis and effects of a genetic polymorphism in CYP26B1 on retinoid catabolism. We found that CYP26B1 mRNA was induced by retinoic acid in human atherosclerotic arteries and CYP26B1 and the macrophage marker CD68 co-localized in human atherosclerotic lesions. In mice, Cyp26B1 mRNA was higher in atherosclerotic than normal arteries. Databases were queried for non-synonymous CYP26B1 SNPs and rs2241057 selected for further studies. Constructs of the CYP26B1 variants were created and used for production of purified proteins and transfection of macrophage-like cells. The minor variant catabolized retinoic acid with significantly higher efficiency, indicating that rs2241057 is functional and suggesting reduced retinoid availability in tissues with the minor variant. rs2241057 was investigated in a Stockholm Coronary Atherosclerosis Risk Factor (SCARF) subgroup. The minor allele was associated with slightly larger lesions as determined by angiography. In summary, this study identifies the first CYP26B1 polymorphism that alters CYP26B1 capacity to metabolize retinoic acid. CYP26B1 was expressed in macrophage-rich areas of human atherosclerotic lesions, induced by retinoic acid and increased in murine atherosclerosis. Taken together, the results indicate that CYP26B1 capacity is genetically regulated and suggest that local CYP26B1 activity may influence atherosclerosis.
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| 6. |
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| 7. |
- Ocaya, Pauline, et al.
(författare)
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CYP26 inhibitor R115866 increases retinoid signaling in intimal smooth muscle cells
- 2007
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - Baltimore, Md : Lippincott Williams & Wilkins. - 1079-5642 .- 1524-4636. ; 27:7, s. 1542-1548
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Intimal smooth muscle cells (SMCs) are dedifferentiated SMCs that have a powerful ability to proliferate and migrate. This cell-type is responsible for the development of intimal hyperplasia after vascular angioplasty. Retinoids, especially all-trans retinoid acid, are known to regulate many processes activated at sites of vascular injury, including modulation of SMC phenotype and inhibition of SMC proliferation. Intracellular levels of active retinoids are under firm control. A key enzyme is the all-trans retinoic acid-degrading enzyme cytochrome p450 isoform 26 (CYP26). Thus, an alternative approach to exogenous retinoid administration could be to increase the intracellular level of all-trans retinoic acid by blocking CYP26-mediated degradation of retinoids. METHODS AND RESULTS: Vascular intimal and medial SMCs expressed CYP26A1 and B1 mRNA. Although medial cells remained unaffected, treatment with the CYP26-inhibitor R115866 significantly increased cellular levels of all-trans retinoic acid in intimal SMCs. The increased levels of all-trans retinoic acid induced retinoid-regulated genes and decreased mitogenesis. CONCLUSIONS: Blocking of the CYP26-mediated catabolism mimics the effects of exogenously administrated active retinoids on intimal SMCs. Therefore, CYP26-inhibitors offer a potential new therapeutic approach to vascular proliferative disorders.
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| 8. |
- Ocaya, Pauline, 1980-
(författare)
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Retinoid metabolism and signalling in vascular smooth muscle cells
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Smooth muscle cells (SMCs) play a major role in cardiovascular diseases. In advanced atherosclerosis, blood flow is impaired due to reduced luminal diameter. Percutaneous vascular interventions, including balloon angioplasty and stent-application are commonly used for the re-establishment of luminal size and improvement of tissue perfusion. However, the benefit of vascular interventions is hampered by re-stenosis. The molecular basis of re-stenosis is not fully elucidated and so far, no successful treatment is clinically available. Re-stenosis, which is proposed to be a response to mechanical injury, involves the activation of multiple processes including inflammation, SMC migration and proliferation, and is characterized by vessel remodelling and intimal hyperplasia. Retinoids have been shown to regulate several processes activated at site of vascular injury including inflammation, SMC migration and proliferation, and have been demonstrated to inhibit SMC proliferation and reduce intimal hyperplasia. Thus, retinoids are potential candidates in the treatment of certain vascular disorders. Retinoid metabolism is complex and involves a repertoire of proteins including retinoic acid synthesizing and catabolizing enzymes. The purpose of this study was to investigate retinoid metabolism in vascular cells, more specifically to find key points in the regulation of retinoid metabolism in vascular SMCs and atherosclerotic lesions. We demonstrate that different phenotypes of SMCs exhibit differences in retinoid metabolism, which suggests a link between retinoid metabolism and the SMC phenotype. Vascular SMCs and atherosclerotic lesions expressed cytochrome P450 isoform 26 (CYP26) enzymes, which are involved in retinoid catabolism. Our studies reveal the presence of a negative feedback loop, in which retinoids induce its inactivation by inducing CYP26 expression in vascular SMCs and atherosclerotic lesions. Moreover, inhibition of CYP26 potently blocked retinoid catabolism and resulted in retinoid-like effects in SMCs, indicating that CYP26 is an important endogenous modulator of retinoid metabolism in vascular cells. In atherosclerotic lesions and vascular SMCs, decreased retinoid catabolism and hence, increased retinoid availability, resulted in increased expression of retinoid-responsive genes. Since retinoids reduce intimal hyperplasia in animal models, our studies suggest that CYP26 inhibitors may provide an alternative to exogenous retinoid administration. Thus, CYP26 inhibitors may offer a new therapeutic approach to vascular proliferative disorders.
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| 9. |
- Sirsjö, Allan, et al.
(författare)
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Retinoic Acid Inhibits Nitric Oxide Synthase-2 Expression through the Retinoic Acid Receptor-alpha
- 2000
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 270:3, s. 846-851
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Tidskriftsartikel (refereegranskat)abstract
- Retinoids are multipotent modulators of cellular functions and suppress cytokine-induced production of nitric oxide (NO) in several cell types. We have explored the mechanisms by which retinoic acid (RA) regulates NO production in rat aortic smooth muscle cells (VSMC), which express NOS2 in response to proinflammatory cytokines. RA inhibited interleukin-1beta (IL-1beta)-induced NOS2 mRNA expression and NO production. These effects were attenuated by the retinoic acid receptor (RAR) antagonist CD3106, indicating that they were mediated through retinoic acid receptors (RARs). The synthetic retinoid agonists CD336 (which specifically binds RARalpha) and CD367 (which binds all RARs) but not agonists specific for RARbeta, RARgamma, or RXRs reduced IL-1beta-induced NOS2 expression and NO production. When transfecting VSMC with a 1570-bp NOS2 promoter fragment fused to a luciferase reporter gene, the NOS2 promoter activity was inhibited by RA. These results indicate that retinoids modulate NO production in VSMC via RARalpha, which inhibits the transcription of the NOS2 gene.
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