Project description:Neuroprotective therapies for retinal degeneration may be used to rescue retinal cells and preserve vision. Hypoxic preconditioning stabilizes the transcription factor HIF-1α in the retina and strongly protects photoreceptors in an animal model of light-induced retinal degeneration. Our data suggest that neuroprotection after hypoxic preconditioning of the retina is the result of the differential expression of a multitude of genes which may act in concert to protect visual cells against a toxic insult. Keywords: hypoxic preconditioning, neuroprotection, transcription-profile, retina
Project description:Neuroprotective therapies for retinal degeneration may be used to rescue retinal cells and preserve vision. Hypoxic preconditioning stabilizes the transcription factor HIF-1α in the retina and strongly protects photoreceptors in an animal model of light-induced retinal degeneration. Our data suggest that neuroprotection after hypoxic preconditioning of the retina is the result of the differential expression of a multitude of genes which may act in concert to protect visual cells against a toxic insult. Experiment Overall Design: In total 24 samples were analyzed on Affymetrix mouse 430.2 arrays, the samples represent different durations of regeneration (none = 0 h, 2 h, 4 h and 16 h) from hypoxic or normoxic treatments, that were tested in triplicates.
Project description:Hypoxic-ischemic (HI) injury in the developing brain is a common cause of disability in children, and there are no effective treatments at this time. Exposure to sublethal hypoxic conditions (hypoxic preconditioning) 24 hours prior to hypoxic-ischemic insult is protective in the developing rat model. We have observed protective effects on brain histopathology and on long-term sensory-motor behavioral tasks. Changes in gene expression are thought to underlie this protective effect. By comparing gene expression in rats subjected to hypoxic preconditioning or sham conditioning at several time points from 0 to 24 hrs after preconditioning, we should gain insight into the mechanisms underlying these neuroprotective effects and may identify targets for therapeutic intervention. The aim of this study is to determine the effect of hypoxic preconditioning on global gene expression, and, in littermates, to examine the effect of hypoxic preconditioning 24 h prior to hypoxic-ischemic insult on brain histopathology. We hypothesize that changes in gene expression underlie the protective effect of hypoxic preconditioning against subsequent hypoxic-ischemic insult. Gene expression will be examined in two groups, 1) preconditioned and 2) sham controls, at 4 time points. On postnatal day 6, preconditioned animals are exposed to normothermic hypoxia for 3 hrs (8.0% oxygen, 36 degrees C), and sham animals are simultaneouosly exposed to normoxia at 36 degrees C. Animals are then returned to their dams until euthanized at 4 time points (0h, 2h, 8h, and 24h later). Five brains/group/timepoint will be used, with an equal number of males and females in each group. Brains are removed and dissected on ice. Cerebral cortex is dissected from both hemispheres and rapidly frozen on dry ice. Total RNA is isolated using the QIAGEN RNeasy Protect Maxi Kit. Littermates of these animals will be exposed to hypoxic preconditioning or sham preconditioning and subjected to hypoxic-ischemic injury 24 h later. These animals are euthanized at postnatal day 14 for histopathologic evaluation of injury.
Project description:Prolonged cellular hypoxia leads to energetic failure and death. However, sublethal hypoxia can trigger an adaptive response called hypoxic preconditioning. While prolyl-hydroxylase (PHD) enzymes and hypoxia inducible factors (HIFs) have been identified as key elements of oxygen sensing machinery, the mechanisms by which hypoxic preconditioning protects against insults remain unclear. Here, we perform serum metabolomic profiling to assess alterations induced by hypoxic preconditioning. We discover that hypoxic preconditioning increases serum kynurenine levels and enhance kynurenine biotransformation leading to preservation of NAD+ in the post-ischemic kidney. Furthermore, we show that Indoleamine 2,3-dioxygenase 1 (Ido1) deficiency abolishes the systemic increase of kynurenine and the subsequent renoprotection generated by hypoxic preconditioning. Importantly, exogenous administration of kynurenine restores the hypoxic preconditioning in the context of Ido1 deficiency. Collectively, our findings demonstrate a critical role of Ido1/kynurenine axis in mediating hypoxic preconditioning
Project description:Prolonged cellular hypoxia leads to energetic failure and death. However, sublethal hypoxia can trigger an adaptive response called hypoxic preconditioning. While prolyl-hydroxylase (PHD) enzymes and hypoxia inducible factors (HIFs) have been identified as key elements of oxygen sensing machinery, the mechanisms by which hypoxic preconditioning protects against insults remain unclear. Here, we perform serum metabolomic profiling to assess alterations induced by hypoxic preconditioning. We discover that hypoxic preconditioning increases serum kynurenine levels and enhance kynurenine biotransformation leading to preservation of NAD+ in the post-ischemic kidney. Furthermore, we show that Indoleamine 2,3-dioxygenase 1 (Ido1) deficiency abolishes the systemic increase of kynurenine and the subsequent renoprotection generated by hypoxic preconditioning. Importantly, exogenous administration of kynurenine restores the hypoxic preconditioning in the context of Ido1 deficiency. Collectively, our findings demonstrate a critical role of Ido1/kynurenine axis in mediating hypoxic preconditioning
Project description:Hypoxic-ischemic (HI) injury in the developing brain is a common cause of disability in children, and there are no effective treatments at this time. Exposure to sublethal hypoxic conditions (hypoxic preconditioning) 24 hours prior to hypoxic-ischemic insult is protective in the developing rat model. We have observed protective effects on brain histopathology and on long-term sensory-motor behavioral tasks. Changes in gene expression are thought to underlie this protective effect. By comparing gene expression in rats subjected to hypoxic preconditioning or sham conditioning at several time points from 0 to 24 hrs after preconditioning, we should gain insight into the mechanisms underlying these neuroprotective effects and may identify targets for therapeutic intervention. The aim of this study is to determine the effect of hypoxic preconditioning on global gene expression, and, in littermates, to examine the effect of hypoxic preconditioning 24 h prior to hypoxic-ischemic insult on brain histopathology. We hypothesize that changes in gene expression underlie the protective effect of hypoxic preconditioning against subsequent hypoxic-ischemic insult. Gene expression will be examined in two groups, 1) preconditioned and 2) sham controls, at 4 time points. On postnatal day 6, preconditioned animals are exposed to normothermic hypoxia for 3 hrs (8.0% oxygen, 36 degrees C), and sham animals are simultaneouosly exposed to normoxia at 36 degrees C. Animals are then returned to their dams until euthanized at 4 time points (0h, 2h, 8h, and 24h later). Five brains/group/timepoint will be used, with an equal number of males and females in each group. Brains are removed and dissected on ice. Cerebral cortex is dissected from both hemispheres and rapidly frozen on dry ice. Total RNA is isolated using the QIAGEN RNeasy Protect Maxi Kit. Littermates of these animals will be exposed to hypoxic preconditioning or sham preconditioning and subjected to hypoxic-ischemic injury 24 h later. These animals are euthanized at postnatal day 14 for histopathologic evaluation of injury. Keywords: time-course
Project description:Fetal asphyctic (FA) preconditioning is effective in attenuating brain damage incurred by a subsequent perinatal asphyctic insult. Unraveling mechanisms of this endogenous neuroprotection, activated by FA preconditioning, is an important step towards new clinical strategies for asphyctic neonates. Genomic reprogramming is thought to be, at least in part, responsible for the protective effect of preconditioning. Therefore, we investigated whole genome differential expression in the preconditioned rat brain.
Project description:Preconditioning strategies like caloric restriction (CR) and hypoxic preconditioning (HP) show remarkable protective effects in animal models of acute kidney injury (AKI). Since the underlying molecular effects are still not fully understood we performed an experiment directly comparing CR and HP in a murine model of ischemia-reperfusion injury (IRI) of the kidney. 8 to 12-week-old, male C57BL6/J mice were either put to 4 weeks of caloric restriction (70% of normal food intake) or placed in a hypoxic chamber (8%O2) for 3 consecutive days prior to IRI. Whole kidneys were used for transcriptional analysis (RNAseq) before and after ischemia-reperfusion injury to look for common effects of both modes of preconditioning.
Project description:Effects of Ischemic Preconditioning, Bevacizumab and Etanercept Ischemia and reperfusion injury provides an acute model of ischemic retinopathy that includes neurodegeneration and VEGF-dependent vascular permeability and is amenable to rapid drug testing. The distinct effects of ischemic preconditioning and bevacizumab demonstrate that the apoptotic and vascular responses to ischemia may be separated and that VEGF expression is not neuroprotective following ischemic-reperfusion. Using transient ischemia followed by reperfusion (IR) to model ischemic retinal disease, this study compares the effects of ischemic preconditioning (IPC) and therapies targeting vascular endothelial growth factor (VEGF) and tumor necrosis factor α (TNFα) on retinal apoptosis, vascular permeability and mRNA biomarker expression. Only the Ischemic Preconditioning (not Bevacizumab and Etanercept treated samples) were hybridized to arrays. Study contains 6 replicates of control and 6 IP treated retinal samples.