| 11. |
- Edsfeldt, Andreas, et al.
(författare)
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Interferon regulatory factor-5-dependent CD11c+ macrophages contribute to the formation of rupture-prone atherosclerotic plaques
- 2022
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 1522-9645 .- 0195-668X. ; 43:19, s. 1864-1877
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Inflammation is a key factor in atherosclerosis. The transcription factor interferon regulatory factor-5 (IRF5) drives macrophages towards a pro-inflammatory state. We investigated the role of IRF5 in human atherosclerosis and plaque stability.METHODS AND RESULTS: Bulk RNA sequencing from the Carotid Plaque Imaging Project biobank were used to mine associations between major macrophage associated genes and transcription factors and human symptomatic carotid disease. Immunohistochemistry, proximity extension assays, and Helios cytometry by time of flight (CyTOF) were used for validation. The effect of IRF5 deficiency on carotid plaque phenotype and rupture in ApoE-/- mice was studied in an inducible model of plaque rupture. Interferon regulatory factor-5 and ITGAX/CD11c were identified as the macrophage associated genes with the strongest associations with symptomatic carotid disease. Expression of IRF5 and ITGAX/CD11c correlated with the vulnerability index, pro-inflammatory plaque cytokine levels, necrotic core area, and with each other. Macrophages were the predominant CD11c-expressing immune cells in the plaque by CyTOF and immunohistochemistry. Interferon regulatory factor-5 immunopositive areas were predominantly found within CD11c+ areas with a predilection for the shoulder region, the area of the human plaque most prone to rupture. Accordingly, an inducible plaque rupture model of ApoE-/-Irf5-/- mice had significantly lower frequencies of carotid plaque ruptures, smaller necrotic cores, and less CD11c+ macrophages than their IRF5-competent counterparts.CONCLUSION: Using complementary evidence from data from human carotid endarterectomies and a murine model of inducible rupture of carotid artery plaque in IRF5-deficient mice, we demonstrate a mechanistic link between the pro-inflammatory transcription factor IRF5, macrophage phenotype, plaque inflammation, and its vulnerability to rupture.KEY QUESTION: The transcription factor interferon regulatory factor-5 (IRF5) is a master regulator of macrophage activation that has been shown to have a role in murine atherogenesis. Its role in human atherosclerosis and its complications is unknown.KEY FINDING: Interferon regulatory factor-5 is linked to plaque vulnerability and symptoms in human carotid endarterectomies. In a murine model of inducible carotid artery plaque rupture, IRF5 drives plaque rupture. Interferon regulatory factor-5 modulates macrophage phenotype and it colocalises with CD11c+ macrophages at the plaque shoulder.TAKE-HOME MESSAGE: We demonstrate a mechanistic link between the IRF5, plaque macrophages, and plaque vulnerability to rupture. Interferon regulatory factor-5 is a potential candidate therapeutic target in human atherosclerosis.
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| 12. |
- Edsfeldt, Andreas, et al.
(författare)
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Transforming growth factor-β2 is associated with atherosclerotic plaque stability and lower risk for cardiovascular events
- 2023
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Ingår i: Cardiovascular Research. - : Oxford University Press. - 0008-6363 .- 1755-3245. ; 119:11, s. 2061-2073
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Transforming growth factor-beta (TGF-β) exists in three isoforms TGF-β1, -β2, and -β3. TGF-β1 has been suggested to be important for maintaining plaque stability, yet the role of TGF-β2 and -β3 in atherosclerosis remains to be investigated. This study explores the association of the three isoforms of TGF-β with plaque stability in the human atherosclerotic disease. Methods and results: TGF-β1, -β2, and -β3 proteins were quantified in 223 human carotid plaques by immunoassays. Indications for the endarterectomy were: symptomatic carotid plaque with stenosis >70% or without symptoms and >80% stenosis. Plaque mRNA levels were assessed by RNA sequencing. Plaque components and extracellular matrix were measured histologically and biochemically. Matrix metalloproteinases and monocyte chemoattractant protein-1 (MCP-1) was measured with immunoassays. The effect of TGF-β2 on inflammation and protease activity was investigated in vitro using THP-1 and RAW264.7 macrophages. Patients were followed longitudinally for cardiovascular (CV) events. TGF-β2 was the most abundant isoform and was increased at both protein and mRNA levels in asymptomatic plaques. TGF-β2 was the main determinant separating asymptomatic plaques in an Orthogonal Projections to Latent Structures Discriminant Analysis. TGF-β2 correlated positively to features of plaque stability and inversely to markers of plaque vulnerability. TGF-β2 was the only isoform inversely correlated to the matrix-degrading matrix metalloproteinase-9 and inflammation in the plaque tissue. In vitro, TGF-β2 pre-treatment reduced MCP-1 gene and protein levels as well as matrix metalloproteinase-9 gene levels and activity. Patients with plaques with high TGF-β2 levels had a lower risk to suffer from future CV events. Conclusions: TGF-β2 is the most abundant TGF-β isoform in human plaques and may maintain plaque stability by decreasing inflammation and matrix degradation.
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| 13. |
- Garcia-Calzon, Sonia, et al.
(författare)
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Epigenetic markers associated with metformin response and intolerance in drug-naive patients with type 2 diabetes
- 2020
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Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 12:561
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Tidskriftsartikel (refereegranskat)abstract
- Metformin is the first-line pharmacotherapy for managing type 2 diabetes (T2D). However, many patients with T2D do not respond to or tolerate metformin well. Currently, there are no phenotypes that successfully predict glycemic response to, or tolerance of, metformin. We explored whether blood-based epigenetic markers could discriminate metformin response and tolerance by analyzing genome-wide DNA methylation in drug-naive patients with T2D at the time of their diagnosis. DNA methylation of 11 and 4 sites differed between glycemic responders/nonresponders and metformin-tolerant/intolerant patients, respectively, in discovery and replication cohorts. Greater methylation at these sites associated with a higher risk of not responding to or not tolerating metformin with odds ratios between 1.43 and 3.09 per 1-SD methylation increase. Methylation risk scores (MRSs) of the 11 identified sites differed between glycemic responders and nonresponders with areas under the curve (AUCs) of 0.80 to 0.98. MRSs of the 4 sites associated with future metformin intolerance generated AUCs of 0.85 to 0.93. Some of these blood-based methylation markers mirrored the epigenetic pattern in adipose tissue, a key tissue in diabetes pathogenesis, and genes to which these markers were annotated to had biological functions in hepatocytes that altered metformin-related phenotypes. Overall, we could discriminate between glycemic responders/nonresponders and participants tolerant/intolerant to metformin at diagnosis by measuring blood-based epigenetic markers in drug-naive patients with T2D. This epigenetics-based tool may be further developed to help patients with T2D receive optimal therapy.
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| 14. |
- García-Calzón, Sonia, et al.
(författare)
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Epigenetic markers associated with metformin response and intolerance in drug-naïve patients with type 2 diabetes
- 2020
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Ingår i: Science Translational Medicine. - 1946-6234. ; 12:561
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Tidskriftsartikel (refereegranskat)abstract
- Metformin is the first-line pharmacotherapy for managing type 2 diabetes (T2D). However, many patients with T2D do not respond to or tolerate metformin well. Currently, there are no phenotypes that successfully predict glycemic response to, or tolerance of, metformin. We explored whether blood-based epigenetic markers could discriminate metformin response and tolerance by analyzing genome-wide DNA methylation in drug-naïve patients with T2D at the time of their diagnosis. DNA methylation of 11 and 4 sites differed between glycemic responders/nonresponders and metformin-tolerant/intolerant patients, respectively, in discovery and replication cohorts. Greater methylation at these sites associated with a higher risk of not responding to or not tolerating metformin with odds ratios between 1.43 and 3.09 per 1-SD methylation increase. Methylation risk scores (MRSs) of the 11 identified sites differed between glycemic responders and nonresponders with areas under the curve (AUCs) of 0.80 to 0.98. MRSs of the 4 sites associated with future metformin intolerance generated AUCs of 0.85 to 0.93. Some of these blood-based methylation markers mirrored the epigenetic pattern in adipose tissue, a key tissue in diabetes pathogenesis, and genes to which these markers were annotated to had biological functions in hepatocytes that altered metformin- related phenotypes. Overall, we could discriminate between glycemic responders/nonresponders and participants tolerant/ intolerant to metformin at diagnosis by measuring blood-based epigenetic markers in drug-naïve patients with T2D. This epigenetics-based tool may be further developed to help patients with T2D receive optimal therapy.
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| 15. |
- Gillberg, Linn, et al.
(författare)
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Adipose tissue transcriptomics and epigenomics in low birthweight men and controls : role of high-fat overfeeding
- 2016
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 59:4, s. 799-812
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Individuals who had a low birthweight (LBW) are at an increased risk of insulin resistance and type 2 diabetes when exposed to high-fat overfeeding (HFO). We studied genome-wide mRNA expression and DNA methylation in subcutaneous adipose tissue (SAT) after 5 days of HFO and after a control diet in 40 young men, of whom 16 had LBW. Methods mRNA expression was analysed using Affymetrix Human Gene 1.0 ST arrays and DNA methylation using Illumina 450K BeadChip arrays. Results We found differential DNA methylation at 53 sites in SAT from LBW vs normal birthweight (NBW) men (false discovery rate < 5%), including sites in the FADS2 and CPLX1 genes previously associated with type 2 diabetes. When we used reference-free cell mixture adjustments to potentially adjust for cell composition, 4,323 sites had differential methylation in LBW vs NBW men. However, no differences in SAT gene expression levels were identified between LBW and NBW men. In the combined group of all 40 participants, 3,276 genes (16.5%) were differentially expressed in SAT after HFO (false discovery rate < 5%) and there was no difference between LBW men and controls. The most strongly upregulated genes were ELOVL6, FADS2 and NNAT; in contrast, INSR, IRS2 and the SLC27A2 fatty acid transporter showed decreased expression after HFO. Interestingly, SLC27A2 expression correlated negatively with diabetes- and obesity-related traits in a replication cohort of 142 individuals. DNA methylation at 652 CpG sites (including in CDK5, IGFBP5 and SLC2A4) was altered in SAT after overfeeding in this and in another cohort. Conclusions/interpretation Young men who had a LBW exhibit epigenetic alterations in their adipose tissue that potentially influence insulin resistance and risk of type 2 diabetes. Short-term overfeeding influences gene transcription and, to some extent, DNA methylation in adipose tissue; there was no major difference in this response between LBW and control participants.
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| 16. |
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| 17. |
- Hall, Elin, et al.
(författare)
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Effects of palmitate on genome-wide mRNA expression and DNA methylation patterns in human pancreatic islets.
- 2014
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Ingår i: BMC Medicine. - : Springer Science and Business Media LLC. - 1741-7015. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Circulating free fatty acids are often elevated in patients with type 2 diabetes (T2D) and obese individuals. Chronic exposure to high levels of saturated fatty acids has detrimental effects on islet function and insulin secretion. Altered gene expression and epigenetics may contribute to T2D and obesity. However, there is limited information on whether fatty acids alter the genome-wide transcriptome profile in conjunction with DNA methylation patterns in human pancreatic islets. To dissect the molecular mechanisms linking lipotoxicity to impaired insulin secretion, we investigated the effects of a 48 h palmitate treatment in vitro on genome-wide mRNA expression and DNA methylation patterns in human pancreatic islets.
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| 18. |
- Hall, Elin, et al.
(författare)
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Glucolipotoxicity alters insulin secretion via epigenetic changes in human islets
- 2019
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 68:10, s. 1965-1974
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 diabetes (T2D) is characterized by insufficient insulin secretion and elevated glucose levels, often in combination with high levels of circulating fatty acids. Long-term exposure to high levels of glucose or fatty acids impair insulin secretion in pancreatic islets, which could partly be due to epigenetic alterations. We studied the effects of high concentrations of glucose and palmitate combined for 48 h (glucolipotoxicity) on the transcriptome, the epigenome, and cell function in human islets. Glucolipotoxicity impaired insulin secretion, increased apoptosis, and significantly (false discovery rate <5%) altered the expression of 1,855 genes, including 35 genes previously implicated in T2D by genomewide association studies (e.g., TCF7L2 and CDKN2B). Additionally, metabolic pathways were enriched for downregulated genes. Of the differentially expressed genes, 1,469 also exhibited altered DNA methylation (e.g., CDK1, FICD, TPX2, and TYMS). A luciferase assay showed that increased methylation of CDK1 directly reduces its transcription in pancreatic β-cells, supporting the idea that DNA methylation underlies altered expression after glucolipotoxicity. Follow-up experiments in clonal β-cells showed that knockdown of FICD and TPX2 alters insulin secretion. Together, our novel data demonstrate that glucolipotoxicity changes the epigenome in human islets, thereby altering gene expression and possibly exacerbating the secretory defect in T2D.
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| 19. |
- Hall, Elin, et al.
(författare)
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Sex differences in the genome-wide DNA methylation pattern and impact on gene expression, microRNA levels and insulin secretion in human pancreatic islets
- 2014
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Ingår i: GenomeBiology. - : Springer Science and Business Media LLC. - 1465-6906. ; 15:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Epigenetic factors regulate tissue-specific expression and X-chromosome inactivation. Previous studies have identified epigenetic differences between sexes in some human tissues. However, it is unclear whether epigenetic modifications contribute to sex-specific differences in insulin secretion and metabolism. Here, we investigate the impact of sex on the genome-wide DNA methylation pattern in human pancreatic islets from 53 males and 34 females, and relate the methylome to changes in expression and insulin secretion. Results: Glucose-stimulated insulin secretion is higher in female versus male islets. Genome-wide DNA methylation data in human islets clusters based on sex. While the chromosome-wide DNA methylation level on the X-chromosome is higher in female versus male islets, the autosomes do not display a global methylation difference between sexes. Methylation of 8,140 individual X-chromosome sites and 470 autosomal sites shows sex-specific differences in human islets. These include sites in/near AR, DUSP9, HNF4A, BCL11A and CDKN2B. 61 X-chromosome genes and 18 autosomal genes display sex-specific differences in both DNA methylation and expression. These include NKAP, SPESP1 and APLN, which exhibited lower expression in females. Functional analyses demonstrate that methylation of NKAP and SPESP1 promoters in vitro suppresses their transcriptional activity. Silencing of Nkap or Apln in clonal beta-cells results in increased insulin secretion. Differential methylation between sexes is associated with altered levels of microRNAs miR-660 and miR-532 and related target genes. Conclusions: Chromosome-wide and gene-specific sex differences in DNA methylation associate with altered expression and insulin secretion in human islets. Our data demonstrate that epigenetics contribute to sex-specific metabolic phenotypes.
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| 20. |
- Hall, Elin, et al.
(författare)
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The effects of high glucose exposure on global gene expression and DNA methylation in human pancreatic islets
- 2018
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207. ; 472, s. 57-67
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Tidskriftsartikel (refereegranskat)abstract
- Background: Type 2 diabetes (T2D) is a complex disease characterised by chronic hyperglycaemia. The effects of elevated glucose on global gene expression in combination with DNA methylation patterns have not yet been studied in human pancreatic islets. Our aim was to study the impact of 48 h exposure to high (19 mM) versus control (5.6 mM) glucose levels on glucose-stimulated insulin secretion, gene expression and DNA methylation in human pancreatic islets. Results: While islets kept at 5.6 mM glucose secreted significantly more insulin in response to short term glucose-stimulation (p = 0.0067), islets exposed to high glucose for 48 h were desensitised and unresponsive to short term glucose-stimulation with respect to insulin secretion (p = 0.32). Moreover, the exposure of human islets to 19 mM glucose resulted in significantly altered expression of eight genes (FDR<5%), with five of these (GLRA1, RASD1, VAC14, SLCO5A1, CHRNA5) also exhibiting changes in DNA methylation (p < 0.05). A gene set enrichment analysis of the expression data showed significant enrichment of e.g. TGF-beta signalling pathway, Notch signalling pathway and SNARE interactions in vesicular transport; these pathways are of relevance for islet function and possibly also diabetes. We also found increased DNA methylation of CpG sites annotated to PDX1 in human islets exposed to 19 mM glucose for 48 h. Finally, we could functionally validate a role for Glra1 in insulin secretion. Conclusion: Our data demonstrate that high glucose levels affect human pancreatic islet gene expression and several of these genes also exhibit epigenetic changes. This might contribute to the impaired insulin secretion seen in T2D.
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