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Genome-wide transcriptional alterations during vascular growth in skeletal muscles of type 2 diabetic mice in response to femoral artery ligation

ABSTRACT: Diabetes is a major risk factor of cardiovascular disease including coronary and peripheral arterial disease, attributed to impaired arteriogenesis and angiogenesis. Mechanisms behind them are poorly understood due to the complexity of these processes in presence of diabetes. To understand the cellular and molecular mechanisms underlying impaired adaptive vascular responses in type 2 diabetic (T2DM) mouse models of hindlimb ischemia using Genome-wide mRNA sequencing.In response to FAL, collateral density and lumen area were significantly reduced in adductor muscles of T2DM mice at day 7 and 14 days post-FAL. mRNA sequencing suggested an altered gene expression typical for monocyte and macrophage (Mϕ) subsets. Similarly, gene expressions typical of dendritic cell and lymphocyte were altered in adductor muscles of T2DM mice. Ischemic muscles of T2DM mice displayed impaired angiogenesis as revealed by endothelial staining. mRNA sequencing suggested downregulation of crucial genes implicated in angiogenesis and differential expression of genes typical for Mϕ subsets. Immunohistochemistry analysis corroborated with the mRNA sequencing analysis, suggesting an altered Mϕ polarization behind the impaired arteriogenesis and angiogenesis seen in T2DM mouse models of hindlimb ischemia.

ORGANISM(S): Mus musculus

PROVIDER: GSE69123 | GEO | 2023/01/30

REPOSITORIES: GEO

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Project description:Purpose: The goal of this study was to compare the genome-wide promoter methylation alterations in macrophages and endothelial cells during hindlimb ischemia among normal, hyperlipidemic and type-2 diabetic mice. Methods: Unilateral hindlimb ischemia was induced by ligating femoral artery proximal to the bifurcation of superficial and deep femoral artery in mice deficient of LDL receptor and expressing only apolipoprotein B100 (LDLR-/-ApoB100/100, C57BL/6J background) (The Jackson Laboratory, Bar Harbor,USA) and mice with Î²-cell specific over-expression of insulin-like growth factor-2 in atherosclerotic background (IGF-II/LDLR-/-ApoB100/100, C57BL/6J background) with type 2 diabetic features on high-fat diet (TD 88173, Harlan Teklad: 42% of calories from fat and 0.15% from cholesterol, no sodium cholate) 8 weeks prior to surgery and continued throughout the study 1. C57BL/6J (WT) mice fed with regular chow-diet (R36, Lactamin) served as controls. All animals were aged between 20 to 24 weeks at the time of hindlimb operations. For sorting macrophages from ischemic muscles, ischemic gastrocnemius muscles were minced and enzymatically dissociated using a cocktail containing 450 U/mL Collagenase I, 125 U/mL Collagenase XI, 60 U/mL DNAseI, and 60 U/mL hyaluronidase (Sigma Aldrich) for 1 h at 37Â°C. The cells were then counted and divided into CD31+ve and CD31-vefractions using CD31 magnetic bead enrichment (Miltenyi Biotec). For macrophage sorting CD31-ve fraction was incubated for 15 minutes with rat anti-mouse CD16/32 mAb (Fc Block, BD-pharmingen) and stained with FITC conjugated rat anti-mouse F4/80 antibody (Serotec) for 20 minutes at 4ËC. For endothelial sorting CD31+ fraction was incubated for 15 minutes with rat anti-mouse CD16/32 mAb (Fc Block, BD-pharmingen) and stained with APC conjugated rat anti-mouse CD31 antibody (BD-pharmingen) and FITC conjugated rat anti-mouse CD45 ((BD-pharmingen) for 20 minutes at 4ËC. FACS sorting was performed on FACS AriaIII (BD Biosciences). Genomic DNA was isolated from FACS sorted macrophages and endothelial cells using AllPrep DNA/RNA/Protein Mini Kit (Qiagen Finland, Helsinki, Finland) according to manufacturer's instructions. Results: The sample similarity as assessed by Pearsonâs correlation matrix and Hierarchial clustering showed high correalation among macrophages, as well as endothelial cells. There was a clear clustering of macrophages and endothelial cells as evidence by their CpG methylation clustering, furthermore macrophages from HL and T2DM mice showed clear clustering compared to control macrophages. Differential methylation analysis of RRBS methylation data from macrophages and endothelial cells was performed using Methylkit. Using a threshold of adjusted p value (Q) <0.05 and percentage methylation difference of >5%, we identified 198 and 272 genes whose promoters were hypomethylated in HL and T2DM macrophages. Similarly, there were 102 and 136 gene promoters were hypermethylated in HL and T2DM macrophages, respectively compare to control macrophages. Thus, proximal promoter methylation suggested that HL and T2DM have convergent influences on the proximal promoter methylation of numerous macrophage specific genes. In order to find out whether these genes with differential methylated promoters were differentially expressed at mRNA expression level in purified macrophages, we further compared our data with the GEO datasets as above. Of the 198 genes with promoter hypomethylation in HL macrophages 72 genes were suggested to be upregulated in M1- MÏs; whereas, of the 102 genes with promoter hypermethylation, 51 genes were suggested to be upregulated in M2- MÏs. Similarly, out of 272 genes with differentially methylated promoters in T2DM macrophages 88 genes were suggested to be upregulated in M1-MÏs; whereas, out of 136 genes with promoter hypermethylation 60 genes were suggested to be upregulated in M2- MÏs. Thus a significant promoter hypomethylation of M1-MÏ and hypermethylation of M2-MÏ genes suggested the predominance of proinflammatory M1-MÏs in ischemic muscles of HL and T2DM compared to M2-MÏs in control mice. Conclusions: We found significant promoter hypomethylation of genes typical for proinflammatory M1-MÏs and hypermethylation of anti-inflammatory, proangiogenic M2-MÏ associated genes in HL and T2DM ischemic muscles. Epigenetic alterations skewing MÏ phenotype towards proinflammatory as opposed to anti-inflammatory, proangiogenic and tissue repair phenotype may contribute to impaired adaptive vascular growth in these pathological conditions. Macrophages and endothelial whole genome DNA methylation was performed in triplicates (Each sample was pooled from 3-4 mice) by RRBS Sequencing approach using Illumina HiSeq 2500. qRTâPCR validation was performed using TaqMan assays.

Project description:Purpose: To clarify cellular and molecular mechanisms underlying impaired post-ischemic adaptive vascular responses and to evaluate reconstituted HDL (rHDL)-ApoA-I nanotherapy to rescue the defect in type 2 diabetic (T2DM) mouse model of hindlimb ischemia (HLI). Methods: Mice with beta-cell specific over-expression of insulin-like growth factor-2 in atherosclerotic background (IGF-II/ LDLR-/-ApoB100/100) with T2DM features were used in the study with C57BL/6J mice fed with a regular chow-diet (R36, Lactamin) serving as controls. Mice aged between 16 to 20 weeks were used in the study . Mice were anaesthetized with 1.5-2% isoflurane/air mixture during the surgical procedure. Hair was removed from the operation site and cleaned with sterile water. Single incision was made just above medial thigh and superficial femoral artery was separated from femoral vein and nerve. HLI was induced by unilateral ligation of femoral artery distal to the origin of the profunda femoral artery. The skin was closed with interrupted silk sutures. Mice were were administered with reconstituted ApoA-I nanoparticles with phosphatidyl serine core (rHDL) intravenously starting 2 days post-HLI with doses every 2 days until scarification with Saline injections serving as controls. Adductors muscle aortic endothelial cells (AECs) and Ischemic muscle Macrophages and Endothelial Cells (ECs) were isolated using a combination of magnetic assisted cell sorting and flow Cytometry using Macrophage (F4/80) and EC (CD-31) specific markers. Total RNA isolated from FACS sorted cells were used for RNA seq library preparation. Results: Cell-specific gene expression, flow cytometry and immunohistochemistry revealed a persistent Macrophage and Endothelial cell inflammation and a reduced anti-inflammatory M2-macrophage activation associated with impaired collateral remodelling and sprouting angiogenesis in T2DM mice. Furthermore, reconstituted HDL (rHDL)- ApoA-I was found to rescue impaired collateral remodelling and angiogenesis in T2DM mice through modulating EC and macrophage phenotypes. Conclusions: Our results suggest that an impaired collateral remodelling and sprouting angiogenesis in T2DM mice after HLI is associated with a persistent EC and macrophage inflammation and a reduced activation of anti-inflammatory M2-macrophage. Skewing the macrophage phenotype towards the pro-arteriogenic and pro-angiogenic anti-inflammatory M2-macrophages using reconstituted HDL (rHDL)-ApoA-I nanotherapy may serve as a potential therapeutic modality for T2DM PAD.

Project description:Purpose: The goal of this study was to compare the genome-wide promoter methylation alterations in macrophages and endothelial cells during hindlimb ischemia among normal, hyperlipidemic and type-2 diabetic mice. Methods: Unilateral hindlimb ischemia was induced by ligating femoral artery proximal to the bifurcation of superficial and deep femoral artery in mice deficient of LDL receptor and expressing only apolipoprotein B100 (LDLR-/-ApoB100/100, C57BL/6J background) (The Jackson Laboratory, Bar Harbor,USA) and mice with β-cell specific over-expression of insulin-like growth factor-2 in atherosclerotic background (IGF-II/LDLR-/-ApoB100/100, C57BL/6J background) with type 2 diabetic features on high-fat diet (TD 88173, Harlan Teklad: 42% of calories from fat and 0.15% from cholesterol, no sodium cholate) 8 weeks prior to surgery and continued throughout the study 1. C57BL/6J (WT) mice fed with regular chow-diet (R36, Lactamin) served as controls. All animals were aged between 20 to 24 weeks at the time of hindlimb operations. For sorting macrophages from ischemic muscles, ischemic gastrocnemius muscles were minced and enzymatically dissociated using a cocktail containing 450 U/mL Collagenase I, 125 U/mL Collagenase XI, 60 U/mL DNAseI, and 60 U/mL hyaluronidase (Sigma Aldrich) for 1 h at 37°C. The cells were then counted and divided into CD31+ve and CD31-vefractions using CD31 magnetic bead enrichment (Miltenyi Biotec). For macrophage sorting CD31-ve fraction was incubated for 15 minutes with rat anti-mouse CD16/32 mAb (Fc Block, BD-pharmingen) and stained with FITC conjugated rat anti-mouse F4/80 antibody (Serotec) for 20 minutes at 4˚C. For endothelial sorting CD31+ fraction was incubated for 15 minutes with rat anti-mouse CD16/32 mAb (Fc Block, BD-pharmingen) and stained with APC conjugated rat anti-mouse CD31 antibody (BD-pharmingen) and FITC conjugated rat anti-mouse CD45 ((BD-pharmingen) for 20 minutes at 4˚C. FACS sorting was performed on FACS AriaIII (BD Biosciences). Genomic DNA was isolated from FACS sorted macrophages and endothelial cells using AllPrep DNA/RNA/Protein Mini Kit (Qiagen Finland, Helsinki, Finland) according to manufacturer's instructions. Results: The sample similarity as assessed by Pearson’s correlation matrix and Hierarchial clustering showed high correalation among macrophages, as well as endothelial cells. There was a clear clustering of macrophages and endothelial cells as evidence by their CpG methylation clustering, furthermore macrophages from HL and T2DM mice showed clear clustering compared to control macrophages. Differential methylation analysis of RRBS methylation data from macrophages and endothelial cells was performed using Methylkit. Using a threshold of adjusted p value (Q) <0.05 and percentage methylation difference of >5%, we identified 198 and 272 genes whose promoters were hypomethylated in HL and T2DM macrophages. Similarly, there were 102 and 136 gene promoters were hypermethylated in HL and T2DM macrophages, respectively compare to control macrophages. Thus, proximal promoter methylation suggested that HL and T2DM have convergent influences on the proximal promoter methylation of numerous macrophage specific genes. In order to find out whether these genes with differential methylated promoters were differentially expressed at mRNA expression level in purified macrophages, we further compared our data with the GEO datasets as above. Of the 198 genes with promoter hypomethylation in HL macrophages 72 genes were suggested to be upregulated in M1- Mϕs; whereas, of the 102 genes with promoter hypermethylation, 51 genes were suggested to be upregulated in M2- Mϕs. Similarly, out of 272 genes with differentially methylated promoters in T2DM macrophages 88 genes were suggested to be upregulated in M1-Mϕs; whereas, out of 136 genes with promoter hypermethylation 60 genes were suggested to be upregulated in M2- Mϕs. Thus a significant promoter hypomethylation of M1-Mϕ and hypermethylation of M2-Mϕ genes suggested the predominance of proinflammatory M1-Mϕs in ischemic muscles of HL and T2DM compared to M2-Mϕs in control mice. Conclusions: We found significant promoter hypomethylation of genes typical for proinflammatory M1-Mϕs and hypermethylation of anti-inflammatory, proangiogenic M2-Mϕ associated genes in HL and T2DM ischemic muscles. Epigenetic alterations skewing Mϕ phenotype towards proinflammatory as opposed to anti-inflammatory, proangiogenic and tissue repair phenotype may contribute to impaired adaptive vascular growth in these pathological conditions.

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Genome-wide transcriptional alterations during vascular growth in skeletal muscles of type 2 diabetic mice in response to femoral artery ligation

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