Gene expression profile at single nuclei level of brain tissues from diabetic mice exposed to acute or recurrent hypoglycemia.
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE226277 | GEO | 2023/10/02
REPOSITORIES: GEO
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Project description:Repeated exposures to insulin-induced hypoglycemia in diabetic patients progressively impair the counter-regulatory response (CRR) that restores normoglycemia. This defect is characterized by reduced secretion of glucagon and other counter-regulatory hormones. Evidence indicates that glucose responsive neurons located in the hypothalamus, orchestrate the CRR. Here, we aimed at identifying the changes in hypothalamic gene and protein expression that underlie impaired CRR. High fat diet fed and low dose streptozocin-treated C57BL6N mice were exposed to one (acute hypoglycemia, AH) or multiple (recurrent hypoglycemia, RH) insulin-induced hypoglycemic episodes. Single nuclei RNA sequencing (snRNAseq) data were obtained from the hypothalamus and cortex of AH and RH mice. Proteomic data were also obtained from hypothalamic synaptosomal fractions. The present study shows that repeated moderate hypoglycemia in diabetic mice lead, in the hypothalamus, to multiple cellular physiology changes, affecting all cell types and their interactions, which show striking features of neurodegenerative diseases. It also shows that repeated hypoglycemic episodes affect very differently the hypothalamus and the cortex.
2023-11-13 | PXD040183 | Pride
Project description:The goal of this study is to determine the effect of mild / moderate hypoglycemia on brain metabolism. To achieve this goal insulin-treated diabetic rats will be subjected to recurrent mild / moderate hypoglycemia.
2015-08-06 | ST000252 | MetabolomicsWorkbench
Project description:In order to gain further insight into the molecular mechanism(s) mediating the blunted epinephrine responses following recurrent hypoglycemia we utilized global gene expression profiling approach. Our results indicate the association between defective counterregulation (impaired epinephrine release) and the activation of the unfolded protein response as well as increased neuropeptide signaling, altered ion homeostasis and downregulation of proteins involved in Ca2+-dependent exocytosis of secretory vesicles. We compared the entire transcriptomes during recurrent (defective CRR model, 2RH) and acute hypoglycemia (normal CRR group, 2RS) in the adrenal medulla of normal Sprague-Dawley rats.
2016-07-01 | E-GEOD-82145 | biostudies-arrayexpress
Project description:Context: We present a case of a young adult with GCK mutation who had neonatal hypoglycaemia, re-emerging with hypoglycaemia later in life. Mechanistic insight is gained from detailed clinical, cellular and genomic analysis. Conclusion: This case highlights the variable phenotype of GCK mutations. In depth molecular analyses in the islets has revealed possible mechanisms for nesidioblastosis and insulin hypersecretion.
2022-03-12 | GSE193693 | GEO
Project description:Aims/hypothesis: Recurrent hypoglycaemia (RH) is a major side-effect of intensive insulin therapy for people with diabetes. Changes in hypoglycaemia sensing by the brain contribute to the development of impaired counterregulatory responses to and awareness of hypoglycaemia. Little is known about the intrinsic changes in human astrocytes in response to acute and recurrent low glucose (RLG) exposure. Methods: Human primary astrocytes (HPA) were exposed to zero, one, three or four bouts of low glucose (0.1 mmol/l) for three hours per day for four days to mimic RH. On the fourth day, DNA and RNA were collected. Differential gene expression and ontology analyses were performed using DESeq2 and GOseq respectively. DNA methylation was assessed using the Infinium MethylationEPIC BeadChip platform. Results: 24 differentially expressed genes (DEGs) were detected (after correction for multiple comparisons). One bout of low glucose exposure had the largest effect on gene expression. Pathway analyses revealed that endoplasmic-reticulum (ER) stress-related genes such as HSPA5, XBP1, and MANF, involved in the unfolded protein response (UPR), were all significantly increased following LG exposure, which was diminished following RLG. There was little correlation between differentially methylated positions and changes in gene expression yet the number of bouts of LG exposure produced distinct methylation signatures. Conclusions/interpretation: These data suggest that exposure of human astrocytes to transient LG triggers activation of genes involved in the UPR linked to endoplasmic reticulum (ER) stress. Following RLG, the activation of UPR related genes was diminished, suggesting attenuated ER stress. This may be mediated by metabolic adaptations to better preserve intracellular and/or ER ATP levels, but this requires further investigation.
2021-02-17 | GSE166845 | GEO
Project description:Aims/hypothesis: Recurrent hypoglycaemia (RH) is a major side-effect of intensive insulin therapy for people with diabetes. Changes in hypoglycaemia sensing by the brain contribute to the development of impaired counterregulatory responses to and awareness of hypoglycaemia. Little is known about the intrinsic changes in human astrocytes in response to acute and recurrent low glucose (RLG) exposure. Methods: Human primary astrocytes (HPA) were exposed to zero, one, three or four bouts of low glucose (0.1 mmol/l) for three hours per day for four days to mimic RH. On the fourth day, DNA and RNA were collected. Differential gene expression and ontology analyses were performed using DESeq2 and GOseq respectively. DNA methylation was assessed using the Infinium MethylationEPIC BeadChip platform. Results: 24 differentially expressed genes (DEGs) were detected (after correction for multiple comparisons). One bout of low glucose exposure had the largest effect on gene expression. Pathway analyses revealed that endoplasmic-reticulum (ER) stress-related genes such as HSPA5, XBP1, and MANF, involved in the unfolded protein response (UPR), were all significantly increased following LG exposure, which was diminished following RLG. There was little correlation between differentially methylated positions and changes in gene expression yet the number of bouts of LG exposure produced distinct methylation signatures. Conclusions/interpretation: These data suggest that exposure of human astrocytes to transient LG triggers activation of genes involved in the UPR linked to endoplasmic reticulum (ER) stress. Following RLG, the activation of UPR related genes was diminished, suggesting attenuated ER stress. This may be mediated by metabolic adaptations to better preserve intracellular and/or ER ATP levels, but this requires further investigation.
2021-02-17 | GSE166847 | GEO
Project description:In order to gain further insight into the molecular mechanism(s) mediating the blunted epinephrine responses following recurrent hypoglycemia we utilized global gene expression profiling approach. Our results indicate the association between defective counterregulation (impaired epinephrine release) and the activation of the unfolded protein response as well as increased neuropeptide signaling, altered ion homeostasis and downregulation of proteins involved in Ca2+-dependent exocytosis of secretory vesicles.
2016-07-01 | GSE82145 | GEO
Project description:It is proposed that the impaired sympathoadrenal response to hypoglycemia induced by recurrent insulin-induced hypoglycemia (RH) is an adaptive phenomenon induced by specific changes in microRNA expression in the ventromedial hypothalamus (VMH). To test this hypothesis, genome-wide microRNAomic profiling of the VMH by RNA-sequencing was performed in control and RH treated rats. Differential expression analysis identified microRNA-7a-5p and microRNA-665 as potential mediators of this phenomenon. To further test this hypothesis, experiments were conducted consisting of targeted lentiviral-mediated overexpression of microRNA-7a-5p and downregulation of microRNA-665 in the VMH. Hyperinsulinemic hypoglycemic clamp experiments demonstrated that targeted overexpression of microRNA-7a-5p (but not downregulation of microRNA-665) in the VMH of RH rats restored the epinephrine response to hypoglycemia. This restored response to hypoglycemia was associated with a restoration of GABAA receptor gene expression. Finally, a direct interaction of microRNA-7a-5p with 3’-UTR of GABAA receptor α1-subunit (Gabra1) gene was demonstrated in a luciferase assay. These findings indicate that 1) the impaired sympathoadrenal response induced by RH is associated with changes in VMH microRNA expression, and 2) microRNA-7a-5p, possibly via direct downregulation of GABA receptor gene expression, may serve as a mediator of the altered sympathoadrenal response to hypoglycemia.
2019-10-17 | GSE138472 | GEO
Project description:The ventromedial hypothalamus (VMN) is implicated in the regulation of many aspects of energy homeostasis, including the counterregulatory response to hypoglycemia. Neurons of the VMN that are activated by hypoglycemia (glucose inhibited neurons (GI)) have been assumed to play a critical, although untested role in this response. Here, we used that expression of a dominant negative form of AMP-activated protein kinase (AMPK) in Sf1 neurons of the VMN which selectively suppressed GI neurons activity. We then performed Translating Ribosome Affinity Purification (TRAP Seq) to evaluate the transcriptional changes induced specifically in that cell population.
2020-10-28 | GSE153872 | GEO
Project description:Glucose is the most important metabolic substrate of the retina and maintenance of nor-moglycemia is an essential challenge for diabetic patients. Glycemic excursions could lead to cardiovascular disease, nephropathy, neuropathy and retinopathy. We recently showed that hy-poglycemia induced retinal cell death in mouse via caspase 3 activation and glutathione (GSH) decrease. Ex vivo experiments in 661W photoreceptor cells confirmed the low-glucose induction of death via superoxide production and activation of caspase 3, which was concomitant with a decrease of GSH content. We evaluate herein retinal gene expression 4 h and 48 h after insulin-induced hypoglycemia. Microarray analysis demonstrated clusters of genes whose expression is modified by hypoglycemia and we discuss the potential implication of those genes in retinal cell death. In addition, we highlight, by gene set enrichment analysis, three important pathways, including KEGG lysosomes, KEGG GSH metabolism and REACTOME apoptosis pathways. We tested the effect of recurrent hypoglycemia (three successive 5h periods of hypoglycemia separated by 48 h recovery) on retinal cell death. Interestingly, exposure to multiple hypoglycemic events prevents retinal cell death and GSH decrease, or adapts the retina to external stress by restoring GSH level comparable to control situation. We hypothesize that scavenger GSH is a key compound in this apoptotic process, and maintaining “normal” GSH level, as well as a strict glycemic control, may represent a therapeutic challenge in order to avoid side effects of diabetes, especially diabetic retinopathy.
2017-01-03 | GSE67523 | GEO