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- Elmabsout, Ali Ateia, et al.
(författare)
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Cloning and Functional Studies of a Splice Variant of CYP26B1 Expressed in Vascular Cells
- 2012
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Ingår i: Plos One. - San Francisco, USA : Public Library of Science (PLoS). - 1932-6203. ; 7:5
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Tidskriftsartikel (refereegranskat)abstract
- Background: All-trans retinoic acid (atRA) plays an essential role in the regulation of gene expression, cell growth and differentiation and is also important for normal cardiovascular development but may in turn be involved in cardiovascular diseases, i.e. atherosclerosis and restenosis. The cellular atRA levels are under strict control involving several cytochromes P450 isoforms (CYPs). CYP26 may be the most important regulator of atRA catabolism in vascular cells. The present study describes the molecular cloning, characterization and function of atRA-induced expression of a spliced variant of the CYP26B1 gene. Methodology/Principal Findings: The coding region of the spliced CYP26B1 lacking exon 2 was amplified from cDNA synthesized from atRA-treated human aortic smooth muscle cells and sequenced. Both the spliced variant and full length CYP26B1 was found to be expressed in cultured human endothelial and smooth muscle cells, and in normal and atherosclerotic vessel. atRA induced both variants of CYP26B1 in cultured vascular cells. Furthermore, the levels of spliced mRNA transcript were 4.5 times higher in the atherosclerotic lesion compared to normal arteries and the expression in the lesions was increased 20-fold upon atRA treatment. The spliced CYP26B1 still has the capability to degrade atRA, but at an initial rate one-third that of the corresponding full length enzyme. Transfection of COS-1 and THP-1 cells with the CYP26B1 spliced variant indicated either an increase or a decrease in the catabolism of atRA, probably depending on the expression of other atRA catabolizing enzymes in the cells. Conclusions/Significance: Vascular cells express the spliced variant of CYP26B1 lacking exon 2 and it is also increased in atherosclerotic lesions. The spliced variant displays a slower and reduced degradation of atRA as compared to the full-length enzyme. Further studies are needed, however, to clarify the substrate specificity and role of the CYP26B1 splice variant in health and disease.
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| 2. |
- Elmabsout, Ali, et al.
(författare)
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Cloning and functional studies of a splice variant of CYP26B1 : a cellular storage protein for all-trans retinoic acid
- 2010
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Ingår i: In Vivo. - 0258-851X .- 1791-7549. ; 24:3, s. 345-346
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundAll-trans retinoic acid (atRA) plays an essential role in the regulation of gene expression, cell growth and differentiation and is also important for normal cardiovascular development but may in turn be involved in cardiovascular diseases, i.e. atherosclerosis and restenosis. The cellular atRA levels are under strict control involving several cytochromes P450 isoforms (CYPs). CYP26 may be the most important regulator of atRA catabolism in vascular cells. The present study describes the molecular cloning, characterization and function of atRA-induced expression of a spliced variant of the CYP26B1 gene.Methodology/Principal FindingsThe coding region of the spliced CYP26B1 lacking exon 2 was amplified from cDNA synthesized from atRA-treated human aortic smooth muscle cells and sequenced. Both the spliced variant and full length CYP26B1 was found to be expressed in cultured human endothelial and smooth muscle cells, and in normal and atherosclerotic vessel. atRA induced both variants of CYP26B1 in cultured vascular cells. Furthermore, the levels of spliced mRNA transcript were 4.5 times higher in the atherosclerotic lesion compared to normal arteries and the expression in the lesions was increased 20-fold upon atRA treatment. The spliced CYP26B1 still has the capability to degrade atRA, but at an initial rate one-third that of the corresponding full length enzyme. Transfection of COS-1 and THP-1 cells with the CYP26B1 spliced variant indicated either an increase or a decrease in the catabolism of atRA, probably depending on the expression of other atRA catabolizing enzymes in the cells.Conclusions/SignificanceVascular cells express the spliced variant of CYP26B1 lacking exon 2 and it is also increased in atherosclerotic lesions. The spliced variant displays a slower and reduced degradation of atRA as compared to the full-length enzyme. Further studies are needed, however, to clarify the substrate specificity and role of the CYP26B1 splice variant in health and disease.
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| 5. |
- Sundin, Johanna, 1982-, et al.
(författare)
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Aberrant mucosal lymphocyte number and subsets in the colon of post-infectious irritable bowel syndrome patients
- 2014
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 49:9, s. 1068-1075
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Tidskriftsartikel (refereegranskat)abstract
- Background: Irritable bowel syndrome (IBS) is characterized by chronic abdominal symptoms such as pain, discomfort, and altered bowel habits. A subset of IBS patients, denoted as post-infectious IBS (PI-IBS) patients, develop symptoms after an enteric infection. Distinct abnormalities in the gut mucosa, including mucosal inflammation, have been proposed to contribute to or be the cause of PI-IBS. This study investigated lymphocyte subsets in PI-IBS patients compared to healthy controls.Materials and methods: Ten PI-IBS patients and nine healthy controls participated. All PI-IBS patients met the Rome III diagnostic criteria for IBS and reported sustained symptoms at least 1 year after an episode of acute gastroenteritis. Intraepithelial lymphocytes and lamina propria lymphocytes (LPLs), isolated from mucosal tissue samples, were stained and analyzed for a comprehensive set of cell markers using flow cytometry.Results: The number of LPLs in PI-IBS was significantly increased compared to those in healthy controls (p < 0.05). PI-IBS patients showed significantly increased proportions of CD45RO(+) CD4(+) activated/memory T cells (p < 0.05) and double-positive CD4(+) CD8(+) cells (p < 0.05), respectively, in the lamina propria. The number of CD19(+) LPLs was decreased in PI-IBS patients compared to healthy controls (p < 0.001).Conclusion: This study presents new evidence that PI-IBS is associated with a sustained aberrant mucosal immune response and support future studies of anti-inflammatory or immune-modulating treatments in these patients.
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| 6. |
- Zegeye, Mulugeta M., 1986-, et al.
(författare)
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Activation of the JAK/STAT3 and PI3K/AKT pathways are crucial for IL-6 trans-signaling-mediated pro-inflammatory response in human vascular endothelial cells
- 2018
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Ingår i: Cell Communication and Signaling. - : BioMed Central (BMC). - 1478-811X. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: IL-6 classic signaling is linked to anti-inflammatory functions while the trans-signaling is associated with pro-inflammatory responses. Classic signaling is induced via membrane-bound IL-6 receptor (IL-6R) whereas trans-signaling requires prior binding of IL-6 to the soluble IL-6R. In both cases, association with the signal transducing gp130 receptor is compulsory. However, differences in the downstream signaling mechanisms of IL-6 classic- versus trans-signaling remains largely elusive.METHODS: In this study, we used flow cytometry, quantitative PCR, ELISA and immuno-blotting techniques to investigate IL-6 classic and trans-signaling mechanisms in Human Umbilical Vein Endothelial Cells (HUVECs).RESULTS: We show that both IL-6R and gp130 are expressed on the surface of human vascular endothelial cells, and that the expression is affected by pro-inflammatory stimuli. In contrast to IL-6 classic signaling, IL-6 trans-signaling induces the release of the pro-inflammatory chemokine Monocyte Chemoattractant Protein-1 (MCP-1) from human vascular endothelial cells. In addition, we reveal that the classic signaling induces activation of the JAK/STAT3 pathway while trans-signaling also activates the PI3K/AKT and the MEK/ERK pathways. Furthermore, we demonstrate that MCP-1 induction by IL-6 trans-signaling requires simultaneous activation of the JAK/STAT3 and PI3K/AKT pathways.CONCLUSIONS: Collectively, our study reports molecular differences in IL-6 classic- and trans-signaling in human vascular endothelial cells; and elucidates the pathways which mediate MCP-1 induction by IL-6 trans-signaling.
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| 8. |
- Zegeye, Mulugeta Melkie, 1986-
(författare)
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Interleukin-6 Signaling Pathways in Human Vascular Endothelial Cells : Molecular Mechanisms and Associations to Atherosclerosis
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Interleukin-6 is pleotropic cytokine produced by several types of cells including endothelial cells (ECs). IL-6 acts on target cells via two major signaling mechanisms known as classic signaling and trans-signaling. Whileactivation of IL-6 classic signaling is associated with homeostatic and tissue regeneration functions, the trans-signaling is linked to pro-inflammatory effects. Our studies reveal that ECs respond to both IL-6 classic- aswell as trans-singling pathways in distinct but also overlapping manner.While IL-6 classic-signaling activated JAK/STAT3 pathway, the trans-signaling additionally engaged PI3K/AKT and MAPK/ERK pathways. Further, IL-6 trans-singling, but not classic signaling, led to secretion of proinflammatory chemokine MCP-1 mainly via JAK/STAT3 and PI3K/AKTpathways. In addition, IL-6 trans-signaling regulate expression of angiogenesis related genes to subsequently impair endothelial tube formationability. Autocrine IL-6 classic-signaling, however, was vital to maintainthe angiogenic response of ECs. Further proteomic analyses showed thatIL-6 trans-signaling in ECs regulates secretion of several inflammatoryproteins and also shifts laminin secretion from LAMA4 to LAMA5, whichmight collectively favor binding and trans-endothelial migration of mononuclear cells. In human atherosclerotic plaques, we found that expression of LAMA4 and LAMA5 is altered compared to healthy vessels, andthat the alteration appears to be associated with immune cell content andstability of the plaque. Using plasma IL-6 binary complex, a novel biomarker, we showed a strong association between IL-6 trans-signalingand risk of future myocardial infarction (MI). In addition, we showed thatelevated plasma IL-6 binary complex mediates the association betweentraditional risk factors (hypertension and smoking) and MI, suggestingthat elevated plasma IL-6 binary complex concentration could partly explain the increased risk of MI in smokers and hypertensive participants.
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