Characterization of a human 12/15-lipoxygenase promoter variant associated with atherosclerosis identifies vimentin as a promoter binding protein

Circulating Vimentin Is Associated With Future Incidence of Stroke in a Population-Based Cohort Study

BACKGROUND AND PURPOSE

VIM (vimentin) is a cytoskeletal intermediate filament protein, which has been linked to atherosclerosis and thrombosis; both are important causes of stroke. We examined the relationship between circulating VIM and incidence of stroke, and if carotid plaque could modify the association in a prospective population-based cohort.

METHODS

This prospective study was based on the Malmö Diet and Cancer Cohort. A total of 4688 participants (39.7% men; mean age, 57.6 years) were examined and blood samples were collected between 1991 and 1994. Incidence of stroke was followed up to 2018. Cox' proportional hazards regression was used to assess the relationship between VIM and stroke.

RESULTS

During a mean follow-up of 22.0 years, a total of 528 subjects were diagnosed with stroke, among which 434 were ischemic stroke. Participants in the highest quartile (vs 1^st quartile) had 1.34× higher risk of total stroke (95% CI, 1.03-1.74) and 1.47× higher of ischemic stroke (95% CI, 1.10-1.98) after adjustment for potential confounders. A significant interaction was found between carotid plaque and VIM with respect to incidence of both total stroke and ischemic stroke (P=0.041 and 0.011, respectively). After stratifying by carotid plaque, high VIM had stronger association with stroke in participants with carotid plaque, especially for the risk of ischemic stroke (adjusted hazard ratio,1.66 [95% CI, 1.23-2.25] for quartile 4 versus quartile 1 to 3).

CONCLUSIONS

VIM is positively associated with the incidence of stroke, especially in individuals with carotid plaque. Further studies are needed to confirm the observed associations.

Ablation of miR-144 increases vimentin expression and atherosclerotic plaque formation

It has been suggested that miR-144 is pro-atherosclerotic via effects on reverse cholesterol transportation targeting the ATP binding cassette protein. This study used proteomic analysis to identify additional cardiovascular targets of miR-144, and subsequently examined the role of a newly identified regulator of atherosclerotic burden in miR-144 knockout mice receiving a high fat diet. To identify affected secretory proteins, miR-144 treated endothelial cell culture medium was subjected to proteomic analysis including two-dimensional gel separation, trypsin digestion, and nanospray liquid chromatography coupled to tandem mass spectrometry. We identified 5 gel spots representing 19 proteins that changed consistently across the biological replicates. One of these spots, was identified as vimentin. Atherosclerosis was induced in miR-144 knockout mice by high fat diet and vascular lesions were quantified by Oil Red-O staining of the serial sectioned aortic root and from en-face views of the aortic tree. Unexpectedly, high fat diet induced extensive atherosclerosis in miR-144 knockout mice and was accompanied by severe fatty liver disease compared with wild type littermates. Vimentin levels were reduced by miR-144 and increased by antagomiR-144 in cultured cardiac endothelial cells. Compared with wild type, ablation of the miR-144/451 cluster increased plasma vimentin, while vimentin levels were decreased in control mice injected with synthetic miR-144. Furthermore, increased vimentin expression was prominent in the commissural regions of the aortic root which are highly susceptible to atherosclerotic plaque formation. We conclude that miR-144 maybe a potential regulator of the development of atherosclerosis via changes in vimentin signaling.

Secretory vimentin is associated with coronary artery disease in patients and induces atherogenesis in ApoE-/- mice

PURPOSE

The present study aimed to investigate the relationship between serum levels of secretory vimentin and coronary artery disease (CAD). The biological effect of secretory vimentin was ascertained by experiments.

METHODS

We analysed serum levels of secretory vimentin in CAD patients (n = 288) and non-CAD controls (n = 195) by ELISA. To evaluate the pro-inflammatory effects of secreted vimentin, the human aortic endothelial cells (HAECs) and human peripheral blood mononuclear cells (PBMCs) were treated with recombinant vimentin or saline. Intraperitoneal injection of vimentin (1 μg/each) or saline was performed every other day for 12 weeks in ApoE^-/- mice for assessment of atherogenic effect.

RESULTS

Serum levels of secretory vimentin were significantly increased in CAD patients than in health controls (p < 0.05), and correlated with the number of diseased coronary arteries, Syntax and Gensini score (for all comparison, p < 0.01). Logistic regression analysis showed that vimentin level is an independent determinant of CAD. In experiments, recombinant vimentin protein enhanced the expression of adhesion molecules and inflammatory cytokines in both endothelial cells and macrophages. This protein also promoted macrophage-endothelial cells adhesion in vitro and the recruitment of leukocytes to mesenteric venules in C57BL/6 mice. Compared with saline, intraperitoneal injection of recombinant vimentin (1 μg/each) every other day induced atherogenesis in ApoE^-/- mice at 12-weeks, with significant increase of inflammatory cytokine and adhesion molecules expression in aortic tissue (p < 0.05).

CONCLUSION

Serum vimentin levels are associated with the presence and the severity of CAD. Vimentin protein promotes atherogenesis in ApoE^-/- mice.

CREB1 functional polymorphisms modulating promoter transcriptional activity are associated with type 2 diabetes mellitus risk in Chinese population

The cAMP responsive element binding protein 1 (CREB1) is a ubiquitous transcription factor that contributes to the regulation of gluconeogenesis. The mechanisms of the CREB1 function remain largely unknown. In this study, we aimed to explore genetic variations in CREB1 promoter region and determine whether these loci affect transcriptional activity and risk on type 2 diabetes (T2D). Three polymorphisms were identified and designated as MU₁, MU₂ and MU₃, respectively. Genotypic distribution analysis revealed that MU₁ genotypes presented similar distribution between T2D and healthy controls (P > 0.05), while the MU₂ and MU₃ showed significant differences (P < 0.05). Haplotypic blocks of the three loci were constructed, and H1-TGA, H2-TTT and H3-ATT had higher frequencies in T2D patients than those in controls. Association studies revealed that the three loci significantly affected plasma glucose, glycated hemoglobin and insulin secretion. Disequilibrium analysis identified that the MU₂ and MU₃ variants were strongly linked in T2D (r² = 0.348, D' = 1.0). Further analysis indicated that MU₂ (TT vs GG, OR = 2.38, 95%CI = 1.19-4.77, P = 0.01) and MU₃ (AA vs TT, OR = 1.16, 95%CI = 1.19-4.77, P = 0.04) were significantly associated with T2D in dominant genotypes. Luciferase assay showed that T-A haplotype from the highly linked MU₂ and MU₃ exhibited maximal promoter activity, which was consistent with the correlation results. We concluded that the TT genotype of MU₂ and the AA genotype of MU₃ could be used as molecular markers for evaluating the risk on T2D.

Evolutionary aspects of lipoxygenases and genetic diversity of human leukotriene signaling

Leukotrienes are pro-inflammatory lipid mediators, which are biosynthesized via the lipoxygenase pathway of the arachidonic acid cascade. Lipoxygenases form a family of lipid peroxidizing enzymes and human lipoxygenase isoforms have been implicated in the pathogenesis of inflammatory, hyperproliferative (cancer) and neurodegenerative diseases. Lipoxygenases are not restricted to humans but also occur in a large number of pro- and eucaryotic organisms. Lipoxygenase-like sequences have been identified in the three domains of life (bacteria, archaea, eucarya) but because of lacking functional data the occurrence of catalytically active lipoxygenases in archaea still remains an open question. Although the physiological and/or pathophysiological functions of various lipoxygenase isoforms have been studied throughout the last three decades there is no unifying concept for the biological importance of these enzymes. In this review we are summarizing the current knowledge on the distribution of lipoxygenases in living single and multicellular organisms with particular emphasis to higher vertebrates and will also focus on the genetic diversity of enzymes and receptors involved in human leukotriene signaling.

Integrative analysis of ocular complications in atherosclerosis unveils pathway convergence and crosstalk

Atherosclerosis is a life-threatening disease and a major cause of mortalities worldwide. While many of the atherosclerotic sequelae are reflected as microvascular effects in the eye, the molecular mechanisms of their development is not yet known. In this study, we employed a systems biology approach to unveil the most significant events and key molecular mediators of ophthalmic sequelae caused by atherosclerosis. Literature mining was used to identify the proteins involved in both atherosclerosis and ophthalmic diseases. A protein-protein interaction (PPI) network was prepared using the literature-mined seed nodes. Network topological analysis was carried out using Cytoscape, while network nodes were annotated using database for annotation, visualization and integrated discovery in order to identify the most enriched pathways and processes. Network analysis revealed that mitogen-activated protein kinase 1 (MAPK1) and protein kinase C occur with highest betweenness centrality, degree and closeness centrality, thus reflecting their functional importance to the network. Our analysis shows that atherosclerosis-associated ophthalmic complications are caused by the convergence of neurotrophin signaling pathways, multiple immune response pathways and focal adhesion pathway on the MAPK signaling pathway. The PPI network shares features with vasoregression, a process underlying multiple vascular eye diseases. Our study presents a first clear and composite picture of the components and crosstalk of the main pathways of atherosclerosis-induced ocular diseases. The hub bottleneck nodes highlight the presence of molecules important for mediating the ophthalmic complications of atherosclerosis and contain five established drug targets for future therapeutic modulation efforts.

Relevance of G-quadruplex structures to pharmacogenetics

G-quadruplexes are non-canonical secondary structures formed within nucleic acids that are involved in modulating cellular processes such as replication, gene regulation, recombination and epigenetics. Within genes, there is mounting evidence of G-quadruplex involvement in transcriptional and post transcriptional regulation. We report the presence of potential G-quadruplex motifs within relevant sites of some important pharmacogenes and discuss the possible implications of this on the function and expression of these genes. Appreciating the location and potential functions of these motifs may be of value when considering the impacts of some pharmacogenetic variants. G-quadruplexes are also the focus of drug development efforts in oncology and we highlight the broader pharmacological implications of treatment strategies that may target G-quadruplexes.