Dysfunctional mitochondria and generation of reactive oxygen species (ROS) promote chronic diseases, which have spurred interest in the molecular mechanisms underlying these conditions. Previously, we have demonstrated that disruption of post-translational modification of proteins with ß-linked N-acetylglucosamine (O- glcnAcylation) via overexpression of the O-glcnAc–regulating enzymes O- glcnAc transferase (OGT) or O- glcnAcase (OGA) impairs mitochondrial function. Here, we report that sustained alterations in O- glcnAcylation either by pharmacological or genetic manipulation also alters metabolic function. Sustained O-glcnAc elevation in SH-SY5Y neuroblastoma cells increased OGA expression and reduced cellular respiration and ROS generation. Cells with elevated O-glcnAc levels had elongated mitochondria and increased mitochondrial membrane potential, and RNA-Seq in SH-SY5Y cells indicated transcriptome reprogramming and down regulation of the NRF2-mediated antioxidant response. Sustained O-glcnAcylation in mice brain and liver validated the metabolic phenotypes observed in the cells, and OGT knockdown in the liver elevated ROS levels, impaired respiration, and increased the NRF2 antioxidant response. Moreover, elevated O-glcnAc levels promoted weight loss and lowered respiration in mice and skewed the mice toward carbohydrate-dependent metabolism as determined by indirect calorimetry. In summary, sustained elevation in O-glcnAcylation coupled with increased OGA expression reprograms energy metabolism, a finding that has potential implications for the etiology, development, and management of metabolic diseases. Overall design: SY5Y cells were adapted to long term O-glcnAcase (OGA) inhibition using the specific OGA inhibitor Thiamet-G (tmg) or glucosamine treatment for 3 weeks. After adaptation to the growth conditions, cells were harvest and RNA isolated for Next Generation RNA sequencing. Briefly, cDNA library was prepared using Illumina TruSeq Stranded mRNA sample preparation kit (Illumina) as manufacturer's instruction. Total RNA was isolated using the same method as previously described and 800 ng of the total RNA per reaction was used to initiate the protocol. The quality of RNA sequencing results was first assessed using FastQC (0.11.2). RSEM (1.2.22) was utilized to align the reads to the human reference genome HG38 and to calculate gene expression values. EdgeR (3.14.0) was then used to normalize the expression values using the TMM-method (weighted trimmed mean of M-values), and for differential expression analyses. First, the negative binomial conditional common likelihood was maximized to estimate a common dispersion value across all genes (estimateCommonDisp). Next, tagwise dispersion values were estimated by an empirical Bayes method based on weighted conditional maximum likelihood (estimateTagwiseDisp). Finally, the differentially gene expression was calculated by computing genewise exact tests for differences in the means between two groups of negative-binomially distributed counts. Hierarchical clustering analysis was determined using Euclidean distance. The following R-packages were utilized for calculations and visualizations: plots and edgeR.
Sustained <i>O-</i>GlcNAcylation reprograms mitochondrial function to regulate energy metabolism.
Specimen part, Cell line, Subject
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Nkx6.1 regulates islet β-cell proliferation via Nr4a1 and Nr4a3 nuclear receptors.
Sex, Age, Specimen part, Treatment
View SamplesLoss of functional -cell mass is a hallmark of Type 1 and Type 2 diabetes, and methods for restoring these cells are needed. Nkx6.1 induces -cell proliferation, but the pathway by which Nkx6.1 activates -cell expansion has not been defined. Here we demonstrate that Nkx6.1 induces expression of the Nr4a1 and Nr4a3 orphan nuclear receptors, and that these factors are both necessary and sufficient for Nkx6.1-mediated -cell proliferation. Overexpression of the Nr4a receptors results in increased expression of key cell cycle inducers E2F1 and cyclin E1. Furthermore, Nr4a receptors induce components of the anaphase-promoting complex, including Ube2c.
Nkx6.1 regulates islet β-cell proliferation via Nr4a1 and Nr4a3 nuclear receptors.
Sex, Age, Specimen part, Treatment
View SamplesLoss of functional -cell mass is a hallmark of Type 1 and Type 2 diabetes, and methods for restoring these cells are needed. We have previously reported that overexpression of the homeodomain transcription factor Nkx6.1 in rat pancreatic islets induces -cell proliferation and enhances glucose-stimulated insulin secretion, but the pathway by which Nkx6.1 activates -cell expansion has not been defined. Here we demonstrate that Nkx6.1 induces expression of the Nr4a1 and Nr4a3 orphan nuclear receptors, and that these factors are both necessary and sufficient for Nkx6.1-mediated -cell proliferation. Consistent with this finding, global knockout of Nr4a1 results in a decrease in -cell area in neonatal and young mice. Overexpression of Nkx6.1 and the Nr4a receptors results in increased expression of key cell cycle inducers E2F1 and cyclin E1. Furthermore, Nkx6.1 and Nr4a receptors induce components of the anaphase-promoting complex, including Ube2c, resulting in degradation of the cell cycle inhibitor p21CIP1. These studies identify a new bipartite pathway for activation of -cell proliferation, suggesting several new targets for expansion of functional -cell mass.
Nkx6.1 regulates islet β-cell proliferation via Nr4a1 and Nr4a3 nuclear receptors.
Sex, Age, Specimen part, Treatment
View SamplesAs somatic cells are converted to iPSCs, their chromatin undergoes wide-ranging rearrangements that affect the ratio of euchromatin-to-heterochromatin, DNA methylation patterns and the regulation of enhancers and promoters. The molecular machinery underlying this process remains largely unknown. Here, we show that Dppa2 and Dppa4, two thus far poorly characterized mES-specific factors, play a key role in resetting the epigenome to a pluripotent configuration. They function as a heterodimer, are induced in late reprogramming intermediates, and are required for reprogramming. When overexpressed with OSKM factors, Dppa2/4 yield reprogramming efficiencies exceeding 75% of the starting culture and accelerate reprogramming kinetics, generating iPSCs in as little as 4 days. When chromatinbound, Dppa2/4 initiate global chromatin decompaction via the DNA damage response pathway, which subsequently activates mES promoters and enhancers and enables an efficient progression to pluripotency. Our work provides critical insights into how the epigenome is remodeled during cell fate transitions. Overall design: Transcriptional regulation by the Dppa2 and Dppa4 investigated by ChIP-Seq and RNA-Seq
Dppa2/4 Facilitate Epigenetic Remodeling during Reprogramming to Pluripotency.
Specimen part, Cell line, Subject
View SamplesRNA sequencing data of macrophages after differentiation in the presence of TPC1 thyroid cancer cell line Overall design: Co-incubation in trans-well system between TPC1 cell lines and human primary macrophages
Transcriptional and metabolic reprogramming induce an inflammatory phenotype in non-medullary thyroid carcinoma-induced macrophages.
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View SamplesGlomerular RNA comparison between wild-type and podocyte specific deletion of the PTIP gene in 1 month old kidneys. The PTIP gene was deleted using a floxed allele and a Podocin-Cre driver strain.
Altering a histone H3K4 methylation pathway in glomerular podocytes promotes a chronic disease phenotype.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells.
Cell line
View SamplesTranscriptome analysis of 130 breast cancer samples (41 TNBC; 30 Her2; 30 Luminal B and 29 Luminal A), 11 normal breast tissue samples and 14 TNBC cell lines.
Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells.
Cell line
View SamplesTranscriptome analysis of 130 breast cancer samples (41 TNBC; 30 Her2; 30 Luminal B and 29 Luminal A), 11 normal breast tissue samples and 14 TNBC cell lines.
Transcriptome analysis of Wnt3a-treated triple-negative breast cancer cells.
Cell line
View Samples