scholarly journals Alteration in Downstream Hypoxia Gene Signaling in Neonatal Glutathione Peroxidase Overexpressing Mouse Brain after Hypoxia-Ischemia

2015 ◽  
Vol 37 (4-5) ◽  
pp. 398-406 ◽  
Author(s):  
R. Ann Sheldon ◽  
Raha Sadjadi ◽  
Matthew Lam ◽  
Russell Fitzgerald ◽  
Donna M. Ferriero
Keyword(s):  
Cell Death ◽  
Brain Injury ◽  
Glutathione Peroxidase ◽  
Apoptotic Cell ◽  
Hypoxia Inducible Factor ◽  
Artery Ligation ◽  
Epo Receptor ◽  
Carotid Artery Ligation ◽  
Mouse Cortex ◽  
Hypoxia Ischemia

We have previously shown that glutathione peroxidase (GPx) overexpressing mice (hGPx-tg) have reduced brain injury after neonatal hypoxia-ischemia (HI) as a consequence of reduced hydrogen peroxide accumulation. However, this protection is reversed with hypoxia preconditioning, raising the question of the roles of the genes regulated by hypoxia-inducible factor-1α (HIF-1α) and their transcription products, such as erythropoietin (EPO), in both the initial protection and subsequent reversal of protection. hGPx-tg and their wild-type (WT) littermates underwent the Vannucci procedure of HI brain injury at postnatal day 9 - left carotid artery ligation followed by exposure to 10% oxygen for 50 min. Brain cortices and hippocampi were subsequently collected 0.5, 4 and 24 h later for the determination of protein expression by Western blot for GPx, HIF-1α, HIF-2α, EPO, EPO receptor, ERK1/2, phospho-ERK1/2, spectrin 145/150 (as a marker of calpain-specific necrotic cell death), and spectrin 120 (as a marker of apoptotic cell death mediated via caspase-3). As expected, the GPx overexpressing mouse cortex had approximately 3 times the GPx expression as WT naïve. Also, GPx expression remained higher in the GPx overexpressing brain than WT at all time points after HI (0.5, 4, 24 h). HIF-1α was not significantly changed in hGPx-tg as a consequence of HI but decreased in the WT cortex 4 h after HI. HIF-2α decreased in the WT hippocampus after HI. EPO was higher in the GPx overexpressing cortex and hippocampus 30 min after HI compared to WT, but the EPO receptor was unchanged by HI. ERK1/2 phosphorylation increased in the hippocampus at 4 h after HI and in the cortex at 24 h after HI in both WT and hGPx-tg. Spectrin 145/150 was increased in the WT cortex at 4 and 24 h after HI, and spectrin 120 increased 24 h after HI, perhaps reflecting greater injury in the WT brain, especially at 24 h when brain injury is more evident. The effect of GPx overexpression does not appear to upregulate the HIF pathway, yet EPO was upregulated, perhaps via ERK. This might explain, in part, why cell death takes a necrotic or apoptotic path. This may also be an explanation for why the GPx overexpressing brain cannot be preconditioned. This information may prove valuable in the development of therapies for neonatal HI brain injury.

scholarly journals Hsp70 Overexpression Sequesters AIF and Reduces Neonatal Hypoxic/Ischemic Brain Injury

2005 ◽  
Vol 25 (7) ◽  
pp. 899-910 ◽  
Author(s):  
Yasuhiko Matsumori ◽  
Shwuhuey M Hong ◽  
Koji Aoyama ◽  
Yang Fan ◽  
Takamasa Kayama ◽  
...  
Keyword(s):  
Cell Death ◽  
Brain Injury ◽  
Ischemic Brain Injury ◽  
Wild Type ◽  
Hsp 70 ◽  
Artery Ligation ◽  
Ischemic Brain ◽  
Carotid Artery Ligation ◽  
High Level ◽  
Apoptosis Inducing Factor

Apoptosis is implicated in neonatal hypoxic/ischemic (H/I) brain injury among various forms of cell death. Here we investigate whether overexpression of heat shock protein (Hsp) 70, an antiapoptotic protein, protects the neonatal brain from H/I injury and the pathways involved in the protection. Postnatal day 7 (P7) transgenic mice overexpressing rat Hsp70 (Tg) and their wild-type littermates (Wt) underwent unilateral common carotid artery ligation followed by 30 mins exposure to 8% O2. Significant neuroprotection was observed in Tg versus Wt mice on both P12 and P21, correlating with a high level of constitutive but not inducible Hsp70 in the Tg. More prominent injury was observed in Wt and Tg mice on P21, suggesting its continuous evolution after P12. Western blot analysis showed that translocation of cytochrome c, but not the second mitochondria-derived activator of caspase (Smac)/DIABLO and apoptosis-inducing factor (AIF), from mitochondria into cytosol was significantly reduced in Tg 24 h after H/I compared with Wt mice. Coimmunoprecipitation detected more Hsp70 bound to AIF in Tg than Wt mice 24 h after H/I, inversely correlating with the amount of nuclear, but not cytosolic, AIF translocation. Our results suggest that interaction between Hsp70 and AIF might have reduced downstream events leading to cell death, including the reduction of nuclear AIF translocation in the neonatal brains of Hsp70 Tg mice after H/I.

scholarly journals Necrostatin Decreases Oxidative Damage, Inflammation, and Injury after Neonatal HI

2010 ◽  
Vol 31 (1) ◽  
pp. 178-189 ◽  
Author(s):  
Frances J Northington ◽  
Raul Chavez-Valdez ◽  
Ernest M Graham ◽  
Sheila Razdan ◽  
Estelle B Gauda ◽  
...  
Keyword(s):  
Cell Death ◽  
Brain Injury ◽  
Oxidative Damage ◽  
Apoptotic Cell ◽  
Death Domain ◽  
Neonatal Brain ◽  
Neonatal Brain Injury ◽  
Markers Of Inflammation ◽  
Gene And Protein Expression ◽  
Hypoxia Ischemia

Necrostatin-1 inhibits receptor-interacting protein (RIP)-1 kinase and programmed necrosis and is neuroprotective in adult rodent models. Owing to the prominence of necrosis and continuum cell death in neonatal hypoxia–ischemia (HI), we tested whether necrostatin was neuroprotective in the developing brain. Postnatal day (P)7 mice were exposed to HI and injected intracerebroventricularly with 0.1 μL of 80 μmol necrostatin, Nec-1, 5-(1H-Indol-3-ylmethyl)-(2-thio-3-methyl) hydantoin, or vehicle. Necrostatin significantly decreased injury in the forebrain and thalamus at P11 and P28. There was specific neuroprotection in necrostatin-treated males. Necrostatin treatment decreased necrotic cell death and increased apoptotic cell death. Hypoxia–ischemia enforced RIP1–RIP3 complex formation and inhibited RIP3–FADD (Fas-associated protein with death domain) interaction, and these effects were blocked by necrostatin. Necrostatin also decreased HI-induced oxidative damage to proteins and attenuated markers of inflammation coincidental with decreased nuclear factor-κB and caspase 1 activation, and FLIP ((Fas-associated death-domain-like IL-1β-converting enzyme)-inhibitory protein) gene and protein expression. In this model of severe neonatal brain injury, we find that cellular necrosis can be managed therapeutically by a single dose of necrostatin, administered after HI, possibly by interrupting RIP1–RIP3-driven oxidative injury and inflammation. The effects of necrostatin treatment after HI reflect the importance of necrosis in the delayed phases of neonatal brain injury and represent a new direction for therapy of neonatal HI.

scholarly journals Proneurotrophins Induce Apoptotic Neuronal Death After Controlled Cortical Impact Injury in Adult Mice

ASN NEURO ◽  
2020 ◽  
Vol 12 ◽  
pp. 175909142093086
Author(s):  
Laura E. Montroull ◽  
Deborah E. Rothbard ◽  
Hur D. Kanal ◽  
Veera D’Mello ◽  
Vincent Dodson ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Cell Death ◽  
Brain Injury ◽  
Neuronal Death ◽  
Apoptotic Cell ◽  
Neuronal Cell ◽  
Adult Brain ◽  
Neurotrophin Receptor ◽  
Cortical Impact ◽  
Impact Injury

The p75 neurotrophin receptor (p75NTR) can regulate multiple cellular functions including proliferation, survival, and apoptotic cell death. The p75NTR is widely expressed in the developing brain and is downregulated as the nervous system matures, with only a few neuronal subpopulations retaining expression into adulthood. However, p75NTR expression is induced following damage to the adult brain, including after traumatic brain injury, which is a leading cause of mortality and disability worldwide. A major consequence of traumatic brain injury is the progressive neuronal loss that continues secondary to the initial trauma, which ultimately contributes to cognitive decline. Understanding mechanisms governing this progressive neuronal death is key to developing targeted therapeutic strategies to provide neuroprotection and salvage cognitive function. In this study, we demonstrate that a cortical impact injury to the sensorimotor cortex elicits p75NTR expression in apoptotic neurons in the injury penumbra, confirming previous studies. To establish whether preventing p75NTR induction or blocking the ligands would reduce the extent of secondary neuronal cell death, we used a noninvasive intranasal strategy to deliver either siRNA to block the induction of p75NTR, or function-blocking antibodies to the ligands pro-nerve growth factor and pro-brain-derived neurotrophic factor. We demonstrate that either preventing the induction of p75NTR or blocking the proneurotrophin ligands provides neuroprotection and preserves sensorimotor function.

Effect of hyperbaric oxygen on apoptosis in neonatal hypoxia-ischemia rat model

2003 ◽  
Vol 95 (5) ◽  
pp. 2072-2080 ◽  
Author(s):  
John W. Calvert ◽  
Changman Zhou ◽  
Anil Nanda ◽  
John H. Zhang
Keyword(s):  
Hyperbaric Oxygen ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Neuroprotective Effect ◽  
Parp Cleavage ◽  
Artery Ligation ◽  
Neonatal Hypoxia ◽  
Rat Pups ◽  
Hypoxia Ischemia ◽  
Expression And Activity

We have previously demonstrated that a transient exposure to hyperbaric oxygen (HBO) attenuated the neuronal injury after neonatal hypoxia-ischemia. This study was undertaken to determine whether HBO offers this neuroprotection by reducing apoptosis in injured brain tissue. Seven-day-old rat pups were subjected to unilateral carotid artery ligation followed by 2 h of hypoxia (8% oxygen). Apoptotic cell death was examined in the injured cortex and hippocampus tissue. Caspase-3 expression and activity increased at 18 and 24 h after the hypoxia-ischemia insult. At 18-48 h, poly(ADP-ribose) polymerase (PARP) cleavage occurred, which reduced the band at 116 kDa and enhanced the band at 85 kDa. There was a time-dependent increase in the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive cells. A single HBO treatment (100% oxygen, 3 ATA for 1 h) 1 h after hypoxia reduced the enhanced caspase-3 expression and activity, attenuated the PARP cleavage, and decreased the number of TUNEL-positive cells observed in the cortex and hippocampus. These results suggest that the neuroprotective effect of HBO is at least partially mediated by the reduction of apoptosis.

Apoptotic Cell Death Under Hypoxia

Physiology ◽  
2014 ◽  
Vol 29 (3) ◽  
pp. 168-176 ◽  
Author(s):  
Ataman Sendoel ◽  
Michael O. Hengartner
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Molecular Oxygen ◽  
Apoptotic Cell ◽  
Hypoxia Inducible Factor ◽  
Apoptotic Cell Death ◽  
Low Oxygen ◽  
Oxygen Levels

Eukaryotic life depends largely on molecular oxygen. During evolution, ingenious mechanisms have evolved that allow organisms to adapt when oxygen levels decrease. Many of these adaptional responses to low oxygen are orchestrated by the heterodimeric transcription factor hypoxia-inducible factor (HIF). Here, we review the link between HIF and apoptosis.

scholarly journals Global Gene Expression in the Immature Brain after Hypoxia-Ischemia

2004 ◽  
Vol 24 (12) ◽  
pp. 1317-1332 ◽  
Author(s):  
Hedtjärn Maj ◽  
Carina Mallard ◽  
Saskia Eklind ◽  
Katarina Gustafson-Brywe ◽  
Henrik Hagberg
Keyword(s):  
Global Gene Expression ◽  
Differentially Expressed ◽  
Global Changes ◽  
Artery Ligation ◽  
Oligonucleotide Arrays ◽  
Genomic Changes ◽  
Neonatal Hypoxia ◽  
Carotid Artery Ligation ◽  
New Genes ◽  
Hypoxia Ischemia

Ischemia induces a complex response of differentially expressed genes in the brain. In order to understand the specific mechanisms of injury in the developing brain, it is important to obtain information on global changes in the transcriptome after neonatal hypoxia-ischemia. In this study, oligonucleotide arrays were used to investigate genomic changes at 2, 8, 24, and 72 hours after neonatal hypoxia-ischemia, which was induced in 9-day-old mice by left carotid artery ligation followed by hypoxia (10% O2). In total, 343 genes were differentially expressed in cortex, hippocampus, thalamus, and striatum 2 to 72 hours after hypoxia-ischemia, when comparing ipsilateral with contralateral hemispheres and with controls, using the significance analysis for microarrays. A total of 283 genes were upregulated and 60 were downregulated, and 94% of the genes had not previously been shown after neonatal hypoxia-ischemia. Genes related to transcription factors and metabolism had mostly upregulated transcripts, whereas most downregulated genes belonged to the categories of ion and vesicular transport and signal transduction. Genes involved in transcription, stress, and apoptosis were induced early after the insult, and many new genes that may play important roles in the pathophysiology of neonatal hypoxiaischemia were identified.

scholarly journals Hypoxia—Ischemia Induces a Rapid Elevation of Ubiquitin Conjugate Levels and Ubiquitin Immunoreactivity in the Immature Rat Brain

1998 ◽  
Vol 18 (4) ◽  
pp. 376-385 ◽  
Author(s):  
Susan J. Vannucci ◽  
Rosemary Mummery ◽  
Richard B. Hawkes ◽  
Christopher C. Rider ◽  
Philip W. Beesley
Keyword(s):  
Rat Brain ◽  
Control Level ◽  
Artery Ligation ◽  
Western Blots ◽  
Immature Rat ◽  
Carotid Artery Ligation ◽  
Hypoxia Ischemia ◽  
The Right ◽  
Ubiquitin Conjugate ◽  
Postnatal Rats

Postnatal rats at 7 and 21 days of age were subjected to unilateral hypoxia—ischemia (H/I) by right carotid artery ligation followed by 1.5 to 2 hours of hypoxia (8% oxygen). Brains were frozen at specific intervals of recovery from 0 to 24 hours. Western blots of samples of right and left forebrain were immunodeveloped with a monoclonal antibody specific for ubiquitin, RHUb 1. An elevation of ubiquitin conjugate levels in the right compared with the left forebrain of 7-day-old animals was detectable immediately following H/I and increased by close to 60% of control level within 1 hour of recovery. The conjugate immunoreactivity remained at this level for 6 hours but had declined to control levels by 24 hours of recovery. No such increase was observed in response to hypoxia alone. Similar changes were observed in samples from the 21-day-old rat brain. However, the elevation of ubiquitin conjugate levels was of slower onset and persisted longer than observed for the 7-day-old animals. Immunocytochemical studies of brain fixed by immersion in formaldehyde/acetone/methanol showed that ubiquitin-like immunoreactivity was increased in the right, but not left, cerebral cortex and hippocampus of animals subjected to H/I. The data suggest that elevated ubiquitination may represent a neuroprotective response to H/I.

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