Project description:Gene expression of macrophages from injured muscles of bDCRE mutant mice was compared with that of Cebpb wt mice. Skeletal muscles were injured by cardiotoxin injection and infiltrating macrophages were isolated 6 days post-injury by FACS sorting of Mac-1+F4/80+ cells. 4 biological replicates were generated for each genotype and expression profiles were determined by hybridization to Affymetrix Moe430_2 arrays.
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 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:Little is known how lincRNAs are involved in skeletal myogenesis. Here we describe the discovery of a novel lincRNA, Linc-YY1 from the promoter of transcription factor (TF) Yin Yang 1 (YY1) gene. We demonstrate that Linc-YY1 is dynamically regulated during myogenesis in vitro and in vivo. Gain or loss of function of Linc-YY1 in C2C12 myoblast cells or satellite cells alters myogenic differentiation and in injured muscles impacts the course of regeneration. Further studies suggest LincYY1 may interact with YY1 through its middle domain to evict YY1
Project description:Mice lacking the developmental axon guidance molecule EphA4 have previously been shown to exhibit extensive axonal regeneration and functional recovery following spinal cord injury. To assess mechanisms by which EphA4 may modify the response to neural injury, a microarray was performed on spinal cord tissue from mice with spinal cord injury and sham injured controls. RNA was purified from spinal cords of adult EphA4 knockout and wild-type mice four days following lumbar spinal cord hemisection or laminectomy only and was hybridised to Affymetrix All-Exon Array 1.0 GeneChips. While subsequent analyses indicated that several pathways were altered in EphA4 knockout mice, of particular interest was the attenuated or otherwise altered expression of a number of inflammatory genes, including Arginase 1, expression of which was lower in injured EphA4 knockout compared to wild-type mice. Immunohistological analyses of different cellular components of the immune response were then performed in injured EphA4 knockout and wild-type spinal cords. While numbers of infiltrating CD3+ T cells were low in the hemisection model, a robust CD11b+ macrophage / microglial response was observed post-injury. There was no difference in the overall number or spread of macrophages / activated microglia in injured EphA4 knockout compared to wild-type spinal cords at two, four or fourteen days post-injury, however a lower proportion of Arginase-1 immunoreactive macrophages / activated microglia was observed in EphA4 knockout spinal cords at four days post-injury. Subtle alterations in the neuroinflammatory response in injured EphA4 knockout spinal cords may contribute to the regeneration and recovery observed in these mice following injury. Comparison was made between gene expression in wild-type and knockout samples both before and after injury. 3 replicates per group.
Project description:Over 50 types of cancer acquire TERT promoter mutations. These single point mutations reactivate telomerase, allowing for indefinite maintenance of telomere length and enabling cellular immortalization. The transcription factor binding site created by the point mutations specifically recruit the ETS factor GABP, a multimeric transcription factor composed of the GABPα and GABPβ subunits. GABP can form two functionally independent transcription factor species – a dimer or a tetramer – depending on which of the structurally distinct GABPβ isoforms is incorporated into the complex. In this study, we show that genetic disruption of GABPβ1L, a tetramer forming isoform of GABPβ that is dispensable in normal development, results in TERT silencing in a TERT promoter mutation dependent manner. Failure to activate TERT expression by GABPβ1L culminates in telomere dysfunction, DNA damage, and mitotic cell death exclusively in TERT promoter mutant cells. Furthermore, exogenous expression of TERT is sufficient to prevent telomere degradation and loss of cell viability in GABPβ1L-reduced lines bearing the mutant TERT promoter. Orthotopic injection of tetramer-deficient mutant TERT promoter GBM cells rendered lower tumor burden and prolonged the overall survival of the tumor-bearing mice. These results highlight the potentially widespread role of GABPB1L in enabling replicative immortality of TERT promoter cancers.
Project description:Mice lacking the developmental axon guidance molecule EphA4 have previously been shown to exhibit extensive axonal regeneration and functional recovery following spinal cord injury. To assess mechanisms by which EphA4 may modify the response to neural injury, a microarray was performed on spinal cord tissue from mice with spinal cord injury and sham injured controls. RNA was purified from spinal cords of adult EphA4 knockout and wild-type mice four days following lumbar spinal cord hemisection or laminectomy only and was hybridised to Affymetrix All-Exon Array 1.0 GeneChips. While subsequent analyses indicated that several pathways were altered in EphA4 knockout mice, of particular interest was the attenuated or otherwise altered expression of a number of inflammatory genes, including Arginase 1, expression of which was lower in injured EphA4 knockout compared to wild-type mice. Immunohistological analyses of different cellular components of the immune response were then performed in injured EphA4 knockout and wild-type spinal cords. While numbers of infiltrating CD3+ T cells were low in the hemisection model, a robust CD11b+ macrophage / microglial response was observed post-injury. There was no difference in the overall number or spread of macrophages / activated microglia in injured EphA4 knockout compared to wild-type spinal cords at two, four or fourteen days post-injury, however a lower proportion of Arginase-1 immunoreactive macrophages / activated microglia was observed in EphA4 knockout spinal cords at four days post-injury. Subtle alterations in the neuroinflammatory response in injured EphA4 knockout spinal cords may contribute to the regeneration and recovery observed in these mice following injury.
Project description:MicroRNA expression profiling during muscle stem cell activation. Quiescent muscle stem cells from uninjured muscles and activated muscle stem cells from injured muscles at indicated time points were isolated by FACS.
Project description:Intramuscular injection of glycerol (Gly) has been reported to lead to skeletal muscle regeneration and ectopic fat deposition. We utilized glycerol injections in the tibialis anterior muscles to investigate the effects of melatonin on skeletal muscle regeneration and intramuscular fat infiltration. We characterized genome-wide expression profiles of tibialis anterior muscles from wild-type mice injured by glycerol injection following melatonin intervention. Mice that were treated with melatonin exhibited improved muscle regeneration and reduced intramuscular fat deposition, which were associated with enhanced myogenesis, remodeled lipid metabolism and reduced immune cell infiltration.
Project description:A phenotypically and functionally distinct population of CD4+ Foxp3+ T cells (Tregs) rapidly accumulates in acutely injured skeletal muscle of mice, just as invading myeloid-lineage cells switch from a pro-inflammatory to a pro-regenerative state. Analysis of gene expression of Tregs and CD4+Foxp3- T cells (Tconvs) from injured muscle and spleen revealed that the transcriptome of muscle Treg cells is distinct from that of splenic Tregs. A set of genes is uniquely expressed by muscle Tregs, while another set is over-expressed by the two muscle populations vis-à-vis their two spleen counterparts. 6 wk-old Foxp3-ires-GFP mice were injured in skeletal muscles with cardiotoxin. Four and fourteen days later, Tregs and Tconvs from spleen and muscle were double-sorted into Trizol. To reduce variability, cells from multiple mice were pooled for sorting, and three replicates were generated for all groups. RNA from 1.5-2.5 x 104 cells was amplified, labeled, and hybridized to Affymetrix Mouse Gene 1.0 ST Arrays.
Project description:PGC1b transgenic mice were generated to selectively over-express PGC1b in skeletal muscles using human skeletal alpha-actin gene promoter. The gene expression profiles were collected from Tibialis anterior (TA) muscles of wild type (WT) and PGC1b transgenic (TG) mice.