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.
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.
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.
Project description:Inflammation is a key component of pathological angiogenesis. Here we induce cornea neovascularisation using sutures placed into the cornea, and sutures are removed to induce a regression phase. We used whole transcriptome microarray to monitor gene expression profies of several genes
