Activation of nuclear factor-kappaB signaling pathway by interleukin-1 after hypoxia/ischemia in neonatal rat hippocampus and cortex

CYR61 is Involved in Neonatal Hypoxic-ischemic Brain Damage Via Modulating Astrocyte-mediated Neuroinflammation

The activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in astrocytes has been found in the hypoxic-ischemic brain damage (HIBD) model. Cysteine rich angiogenic inducer 61 (CYR61) is secreted by reactive astrocytes. However, the effects of CYR61 on HIBD and its related mechanisms remain unclear. This study sought to explore the role of CYR61 in the activation of astrocytes and the NLRP3 inflammasome in neonatal HIBD. HIBD models were established in 7-day Sprague-Dawley rat pups. Neurobehavioral evaluation and 2,3,5-triphenyl-tetrazolium chloride staining were performed. In addition, rat primary astrocytes were used to establish the cell model of HIBD in vitro by oxygen-glucose deprivation/reperfusion (OGD/R). Then, CYR61-overexpression and sh-CYR61 viruses mediated by lentivirus were transduced into ODG/R-treated primary astrocytes. The expressions of related genes were evaluated using real-time quantitative PCR, western blot, immunofluorescence staining, and Enzyme-linked immunosorbent assay. The results showed that hypoxia-ischemia induced short-term neurological deficits, neuronal damage, and cerebral infarction in neonatal rats. In vivo, the expressions of CYR61, NLRP3, and glial fibrillary acidic protein (GFAP) were up-regulated in the HIBD model. In vitro, CYR61 exhibited high expression. CYR61 overexpression increased the expressions of GFAP and C3, whereas decreased S100A10 expression. CYR61 overexpression increased the expression of NLRP3, ASC, caspase-1 p20 and IL-1β. CYR61 overexpression activated NF-κB by promoting the phosphorylation of IκBα and p65. Thus, CYR61 is involved in neonatal HIBD progress, which may be related to the activation of astrocytes, the NLRP3 inflammasome, and the NF-κB signaling pathway.

Identification of Novel Circular RNA Targets in Key Penumbra Region of Rats After Cerebral Ischemia-Reperfusion Injury

Circular RNAs (circRNAs) are abundantly and stably expressed in the brain of mammals and humans. Some circRNAs are implicated in ischemic stroke. Therefore, we aimed to detect how circRNAs change in the key penumbra area during cerebral ischemia-reperfusion (CI/R) injury. Rats were subjected to transient middle cerebral artery occlusion (tMCAO), during which the permanent blocking period was 2 h and reperfusion time was 24 or 72 h. Then modified neurologic severity score (mNSS), triphenyl tetrazolium chloride (TTC) staining and HE staining were used to exhibiting damage between rats in different groups. The penumbra regions of all rats were dissected and total RNA was further processed for high-throughput sequencing. CircRNA expression profiles were screened and bioinformatics analyses were conducted to investigate these differentially expressed circRNAs. Some of them were verified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), followed by the establishment of a circRNA-miRNA-mRNA network and the detection of their downstream molecules. A total of 99 and 98 circRNAs were differentially expressed at CI/R 24 h and CI/R 72 h, respectively. Notably, 21 circRNAs significantly changed at both reperfusion points. Three circRNAs, namely circ.7225, circ.5415, and circ.20623 were found to be associated with CI/R injury and might be preferred targets. Common downstream miR-298-5p and Bcl-3 were found to make up the circRNA-miRNA-mRNA network. Novel circRNA targets came to light in the penumbra of rats during CI/R injury and might establish the circRNA-miRNA-mRNA relationship, thus serving as potential biomarkers for ischemic stroke treatment.

Neonatal asphyxia as an inflammatory disease: Reactive oxygen species and cytokines

Neonatologists resuscitate asphyxiated neonates by every available means, including positive ventilation, oxygen therapy, and drugs. Asphyxiated neonates sometimes present symptoms that mimic those of inflammation, such as fever and edema. The main pathophysiology of the asphyxia is inflammation caused by hypoxic-ischemic reperfusion. At birth or in the perinatal period, neonates may suffer several, hypoxic insults, which can activate inflammatory cells and inflammatory mediator production leading to the release of larger quantities of reactive oxygen species (ROS). This in turn triggers the production of oxygen stress-induced high mobility group box-1 (HMGB-1), an endogenous damage-associated molecular patterns (DAMPs) protein bound to toll-like receptor (TLR) -4, which activates nuclear factor-kappa B (NF-κB), resulting in the production of excess inflammatory mediators. ROS and inflammatory mediators are produced not only in activated inflammatory cells but also in non-immune cells, such as endothelial cells. Hypothermia inhibits pro-inflammatory mediators. A combination therapy of hypothermia and medications, such as erythropoietin and melatonin, is attracting attention now. These medications have both anti-oxidant and anti-inflammatory effects. As the inflammatory response and oxidative stress play a critical role in the pathophysiology of neonatal asphyxia, these drugs may contribute to improving patient outcomes.

Regulation of glutamate transport and neuroinflammation in a term newborn rat model of hypoxic–ischaemic brain injury

In the newborn brain, moderate-severe hypoxia–ischaemia induces glutamate excitotoxicity and inflammation, possibly via dysregulation of candidate astrocytic glutamate transporter ( Glt1) and pro-inflammatory cytokines (e.g. Tnfα, Il1β, Il6). Epigenetic mechanisms may mediate dysregulation. Hypotheses: (1) hypoxia–ischaemia dysregulates mRNA expression of these candidate genes; (2) expression changes in Glt1 are mediated by DNA methylation changes; and (3) methylation values in brain and blood are correlated. Seven-day-old rat pups ( n = 42) were assigned to nine groups based on treatment (for each timepoint: naïve ( n = 3), sham ( n = 3), hypoxia–ischaemia ( n = 8) and timepoint for tissue collection (6, 12 and 24 h post-hypoxia). Moderate hypoxic–ischemic brain injury was induced via ligation of the left common carotid artery followed by 100 min hypoxia (8% O2, 36°C). mRNA was quantified in cortex and hippocampus for the candidate genes, myelin ( Mbp), astrocytic ( Gfap) and neuronal ( Map2) markers (qPCR). DNA methylation was measured for Glt1 in cortex and blood (bisulphite pyrosequencing). Hypoxia–ischaemia induced pro-inflammatory cytokine upregulation in both brain regions at 6 h. This was accompanied by gene expression changes potentially indicating onset of astrogliosis and myelin injury. There were no significant changes in expression or promoter DNA methylation of Glt1. This pilot study supports accumulating evidence that hypoxia–ischaemia causes neuroinflammation in the newborn brain and prioritises further expression and DNA methylation analyses focusing on this pathway. Epigenetic blood biomarkers may facilitate identification of high-risk newborns at birth, maximising chances of neuroprotective interventions.

2-Methoxy-1,4-naphthoquinone (MNQ) regulates cancer key genes of MAPK, PI3K, and NF-κB pathways in Raji cells

2-Methoxy-1,4-naphthoquinone (MNQ) has been shown to cause cytotoxic towards various cancer cell lines. This study is designed to investigate the regulatory effect of MNQ on the key cancer genes in mitogen-activated protein kinase, phosphoinositide 3-kinase, and nuclear factor кB signaling pathways. The expression levels of the genes were compared at different time point using polymerase chain reaction arrays and Ingenuity Pathway Analysis was performed to identify gene networks that are most significant to key cancer genes. A total of 43 differentially expressed genes were identified with 21 up-regulated and 22 down-regulated genes. Up-regulated genes were involved in apoptosis, cell cycle and act as tumor suppressor while down-regulated genes were involved in anti-apoptosis, angiogenesis, cell cycle and act as transcription factor as well as proto-oncogenes. MNQ exhibited multiple regulatory effects on the cancer key genes that targeting at cell proliferation, cell differentiation, cell transformation, apoptosis, reduce inflammatory responses, inhibits angiogenesis and metastasis.

Mechanism underlying circularRNA_014301-mediated regulation of neuronal cell inflammation and apoptosis

Spinal cord injury (SCI) causes damage to the spinal cord owing to trauma or disease and myelinated fiber tracts that transmit sensation and motor signals to and from the brain. Circular RNAs (circRNAs) are a recently discovered class of regulatory molecules, and their roles in SCI are still unknown. circRNA_014301 was indicated to be differentially expressed in the spinal cord at the site of SCI in a rat model. To analyze the role of circRNA_014301 in SCI, we exposed rat adrenal pheochromocytoma PC12 cells were exposed to increasing concentrations of lipopolysaccharide (LPS) and to construct a PC12 cell inflammatory model. Cell Counting Kit-8 assay was used to analyze cell viability. Reverse transcription-quantitative PCR and ELISA were used to detect the expression of inflammatory factors (IL-1β, IL-6 and TNF-α). Annexin V-FITC/PI double staining was employed to detect cell apoptosis, and western blotting was performed to detect the expression of apoptotic proteins (Bax/Bcl-2/cleaved caspase-3) and NF-κB. The results demonstrated that LPS induced inflammation in PC12 cells as evidenced by the reduced cell proliferation and enhanced expression of inflammatory and apoptotic factors under increasing LPS concentrations. Western blotting analyses indicated that circRNA_014301 induced the expression of p-NF-κB/NF-κB, Bax and cleaved caspase-3, and decreased the expression of Bcl-2 following LPS-induced inflammation, and this apoptosis-promoting effect was relieved by small interfering-RNA-mediated knockdown of circRNA_014301. Thus, circRNA_014301 silencing alleviated apoptosis and inflammation in PC12 cells. SCI is invariably associated with spinal cord inflammation, and LPS was used to stimulate apoptosis and inflammatory injury in PC12 cells, and create a cell model of SCI. By promoting PC12 cell apoptosis under inflammatory conditions, it was indicated that circRNA_014301 may suppress SCI. Therefore, circRNA_014301 may represent a potential target for SCI diagnosis and therapy.

Orexin-A alleviates astrocytic apoptosis and inflammation via inhibiting OX1R-mediated NF-κB and MAPK signaling pathways in cerebral ischemia/reperfusion injury

Orexin-A (OXA) is a neuropeptide with neuroprotective effect by reducing cerebral ischemia/reperfusion injury (CIRI). Inflammation and apoptosis mediated by astrocyte activation are the key pathological mechanisms for CIRI. We thus attempted to confirm neuroprotective effects of OXA on astrocytic inflammation and apoptosis in CIRI and clarify the relative mechanisms. A middle cerebral artery occlusion and reperfusion (MCAO/R) rat model and U251 glioma cells model subjected to oxygen glucose deprivation and reperfusion (OGD/R) were established, with or without OXA treatment. Neurological deficit score was determined, and cerebral infarct volume was evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Western Blot was used to detect the expressions of NF-κB p65, p-p65, p-ERK, p-p38, GFAP, OX1R, IL-1β, TNF-α, IL-6, iNOS, Bcl-2, Bax, CytC, cleaved caspase-9 and cleaved caspase-3 in vivo and in vitro. Pro-inflammatory cytokines in cell supernatant IL-1β, TNF-α and IL-6 were determined by ELISA. Hoechst 33342 staining was used to detect the apoptosis of astrocyte. Immunofluorescent staining was performed to assess the nuclear translocation of p65 and the expression of GFAP. The results showed that OXA significantly improved neurological deficit score and decreased the volume of infarct area in brain. OXA decreased inflammatory mediators, inhibited astrocyte activation and nuclear translocation of NF-κB and phosphorylation of NF-κB, MAPK/ERK and MAPK/p38. Besides, OXA suppressed apoptosis via upregulating the ratio of Bcl-2/Bax and downregulating cytochrome C, cleaved-caspase-9 and cleaved caspase-3. Overall, it was concluded that OXA exerts neuroprotective effect during CIRI through attenuating astrocytes apoptosis, astrocytes activation and pro-inflammatory cytokines production, by Inhibiting OX1R-mediated NF-κB, MAPK/ERK and MAPK/p38 signaling pathways. The progress in our study is helpful to elucidate the molecular mechanisms of OXA neuroprotection, which could lead to the development of new treatment strategies for ischemic stroke.

Cooling and immunomodulation for treating hypoxic-ischemic brain injury

Therapeutic hypothermia is now well established to partially reduce disability in term and near-term infants with moderate-severe hypoxic-ischemic encephalopathy. Preclinical and clinical studies have confirmed that current protocols for therapeutic hypothermia are near optimal. The challenge is now to identify complementary therapies that can further improve outcomes, in combination with therapeutic hypothermia. Overall, anti-excitatory and anti-apoptotic agents have shown variable or even no benefit in combination with hypothermia, suggesting overlapping mechanisms of neuroprotection. Inflammation appears to play a critical role in the pathogenesis of injury in the neonatal brain, and thus, there is potential for drugs with immunomodulatory properties that target inflammation to be used as a therapy in neonates. In this review, we examine the evidence for neuroprotection with immunomodulation after hypoxia-ischemia. For example, stem cell therapy can reduce inflammation, increase cell survival, and promote cell maturation and repair. There are also encouraging preclinical data from small animals suggesting that stem cell therapy can augment hypothermic neuroprotection. However, there is conflicting evidence, and rigorous testing in translational animal models is now needed.

Bcl-3 promotes Wnt signaling by maintaining the acetylation of β-catenin at lysine 49 in colorectal cancer

Wnt/β-catenin signaling plays a critical role in colorectal cancer (CRC) tumorigenesis and the homeostasis of colorectal cancer stem cells (CSCs), but its molecular mechanism remains unclear. B-cell lymphoma 3 (Bcl-3), a member of the IκB family, is overexpressed in CRC and promotes tumorigenicity. Here, we report a novel function of Bcl-3 in maintaining colorectal CSC homeostasis by activating Wnt/β-catenin signaling. Silencing Bcl-3 suppresses the self-renewal capacity of colorectal CSCs and sensitizes CRC cells to chemotherapeutic drugs through a decrease in Wnt/β-catenin signaling. Moreover, our data show that Bcl-3 is a crucial component of Wnt/β-catenin signaling and is essential for β-catenin transcriptional activity in CRC cells. Interestingly, Wnt3a increases the level and nuclear translocation of Bcl-3, which binds directly to β-catenin and enhances the acetylation of β-catenin at lysine 49 (Ac-K49-β-catenin) and transcriptional activity. Bcl-3 depletion decreases the Ac-K49-β-catenin level by increasing the level of histone deacetylase 1 to remove acetyl groups from β-catenin, thus interrupting Wnt/β-catenin activity. In CRC clinical specimens, Bcl-3 expression negatively correlates with the overall survival of CRC patients. A significantly positive correlation was found between the expression of Bcl-3 and Ac-K49-β-catenin. Collectively, our data reveal that Bcl-3 plays a crucial role in CRC chemoresistance and colorectal CSC maintenance via its modulation of the Ac-K49-β-catenin, which serves as a promising therapeutic target for CRC.

Exercise-induced α-ketoglutaric acid stimulates muscle hypertrophy and fat loss through OXGR1-dependent adrenal activation

Beneficial effects of resistance exercise on metabolic health and particularly muscle hypertrophy and fat loss are well established, but the underlying chemical and physiological mechanisms are not fully understood. Here, we identified a myometabolite‐mediated metabolic pathway that is essential for the beneficial metabolic effects of resistance exercise in mice. We showed that substantial accumulation of the tricarboxylic acid cycle intermediate α‐ketoglutaric acid (AKG) is a metabolic signature of resistance exercise performance. Interestingly, human plasma AKG level is also negatively correlated with BMI. Pharmacological elevation of circulating AKG induces muscle hypertrophy, brown adipose tissue (BAT) thermogenesis, and white adipose tissue (WAT) lipolysis in vivo. We further found that AKG stimulates the adrenal release of adrenaline through 2‐oxoglutarate receptor 1 (OXGR1) expressed in adrenal glands. Finally, by using both loss‐of‐function and gain‐of‐function mouse models, we showed that OXGR1 is essential for AKG‐mediated exercise‐induced beneficial metabolic effects. These findings reveal an unappreciated mechanism for the salutary effects of resistance exercise, using AKG as a systemically derived molecule for adrenal stimulation of muscle hypertrophy and fat loss.

Corticosteroids and perinatal hypoxic-ischemic brain injury

Perinatal hypoxic-ischemic (HI) brain injury is the major cause of neonatal mortality and severe long-term neurological morbidity. Yet, the effective therapeutic interventions currently available are extremely limited. Corticosteroids act on both mineralocorticoid (MR) and glucocorticoid (GR) receptors and modulate inflammation and apoptosis in the brain. Neuroinflammatory response to acute cerebral HI is a major contributor to the pathophysiology of perinatal brain injury. Here, we give an overview of current knowledge of corticosteroid-mediated modulations of inflammation and apoptosis in the neonatal brain, focusing on key regulatory cells of the innate and adaptive immune response. In addition, we provide new insights into targets of MR and GR in potential therapeutic strategies that could be beneficial for the treatment of infants with HI brain injury.

Endocan silencing induces programmed cell death in hepatocarcinoma

Hepatocarcinoma is a type of high-grade malignant carcinoma identified worldwide. Its rapid development and late diagnosis prevents effective tumor resection in the majority of patients, and therefore recent studies have targeted metabolic signaling pathways and the tumor microenvironment for potential treatments. To investigate whether endocan may be a gene target for hepatocarcinoma treatment, the present study employed the following measures: MTT and Transwell assays, flow cytometry, western blotting and an mRFP-GFP-LC3 double fluorescence system. Following endocan gene silencing, cell proliferation was significantly inhibited and the number of invasive cells in the endocan siRNA-treated group was reduced compared with the control-siRNA treated-group. Furthermore, the apoptosis rate was 15% and autophagy was detected in the endocan short interfering (si)RNA-treated group compared with the control-siRNA treated-group. Using western blotting to detect NF-κB expression in the nucleus, the NF-κB expression was identified to be significantly reduced in the siRNA-treated group compared with the control groups. Endocan gene silencing inhibited hepatocarcinoma cell viability and invasion, whilst inducing apoptosis and autophagy. The results of the present study suggest that the effect of endocan gene silencing on cell survival was mediated via the NF-κB signaling pathway.

Neuroprotective Effect of Chitosan Oligosaccharide on Hypoxic-Ischemic Brain Damage in Neonatal Rats

Neonatal hypoxic-ischemic brain damage (HIBD) is one of the leading causes of neonatal mortality and permanent neurological disability worldwide and the effective treatment strategies are not yet available. It has been demonstrated that Chitosan oligosaccharide (COS) exerts protective effect in vitro ischemic brain injury. However, no information is available on possible effects of COS on neonatal HIBD. To investigate the hypothesis of the potential neuroprotective effect of COS on the brain injury due to HIBD, 7-day-old Sprague-Dawley rats were treated with left carotid artery ligation followed by exposure to 8% oxygen (balanced with nitrogen) for 2.5 h at 37 °C. After COS treatment, the cerebral damage was measured by behavior tasks, 2,3,5-triphenyltetrazolium chloride(TTC), Hematoxyline-Eosin(HE), Nissl and Fluoro-Jade B(FJB)staining. In addition, the oxidative stress were assayed with ipsilateral hemisphere homogenates. Immunofluorescence staining were used to examine the activation of the astrocyte and microglia. Expression of inflammatory-related proteins were analyzed by western-blot analysis. In this study we found that administration of COS ameliorated early neurological reflex behavior, significantly reduce brain infarct volume and attenuated neuronal cell injury and degeneration. Furthermore, COS markedly decreased the level of MDA, lactic acid and increased SOD, GSH-Px and T-AOC. COS attenuated hypoxic-ischemic induced up-regulation of expressions of interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), meanwhile it dramatically increased the interleukin-10 (IL-10). These results suggest that COS exerts neuroprotection on hypoxic-ischemic brain damage in neonatal rats, it implies COS might be a potential therapeutic for the treatment of HIBD.

Neutralizing anti-interleukin-1β antibodies reduce ischemia-related interleukin-1β transport across the blood-brain barrier in fetal sheep

Hypoxic ischemic insults predispose to perinatal brain injury. Pro-inflammatory cytokines are important in the evolution of this injury. Interleukin-1β (IL-1β) is a key mediator of inflammatory responses and elevated IL-1β levels in brain correlate with adverse neurodevelopmental outcomes after brain injury. Impaired blood-brain barrier (BBB) function represents an important component of hypoxic-ischemic brain injury in the fetus. In addition, ischemia-reperfusion increases cytokine transport across the BBB of the ovine fetus. Reducing pro-inflammatory cytokine entry into brain could represent a novel approach to attenuate ischemia-related brain injury. We hypothesized that infusions of neutralizing IL-1β monoclonal antibody (mAb) reduce IL-1β transport across the BBB after ischemia in the fetus. Fetal sheep were studied 24-h after 30-min of carotid artery occlusion. Fetuses were treated with placebo- or anti-IL-1β mAb intravenously 15-min and 4-h after ischemia. Ovine IL-1β protein expressed from IL-1β pGEX-2T vectors in Escherichia coli (E. coli) BL-21 cells was produced, purified, and radiolabeled with ¹²⁵I. BBB permeability was quantified using the blood-to-brain transfer constant (K_i) with ¹²⁵I-radiolabeled-IL-1β. Increases in anti-IL-1β mAb were observed in the brain of the mAb-treated group (P<0.001). Blood-to-brain transport of ¹²⁵I-IL-1β was lower (P<0.04) across brain regions in the anti-IL-1β mAb-treated than placebo-treated ischemic fetuses. Plasma ¹²⁵I-IL-1β counts were higher (P<0.001) in the anti-IL-1β mAb- than placebo-treated ischemic fetuses. Systemic infusions of anti-IL-1β mAb reduce IL-1β transport across the BBB after ischemia in the ovine fetus. Our findings suggest that conditions associated with increases in systemic pro-inflammatory cytokines and neurodevelopmental impairment could benefit from an anti-cytokine therapeutic strategy.

Saponins from Panax japonicus attenuate age-related neuroinflammation via regulation of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways

Neuroinflammation is recognized as an important pathogenic factor for aging and related cognitive disorders. Mitogen-activated protein kinase and nuclear factor kappa B signaling pathways may mediate neuroinflammation. Saponins from Panax japonicus are the most abundant and bioactive members in rhizomes of Panax japonicus, and show anti-inflammatory activity. However, it is not known whether saponin from Panax japonicus has an anti-inflammatory effect in the aging brain, and likewise its underlying mechanisms. Sprague-Dawley rats were divided into control groups (3-, 9-, 15-, and 24-month-old groups) and saponins from Panax japonicus-treated groups. Saponins from Panax japonicus-treated groups were orally administrated saponins from Panax japonicus at three doses of 10, 30, and 60 mg/kg once daily for 6 months until the rats were 24 months old. Immunohistochemical staining and western blot assay results demonstrated that many microglia were activated in 24-month-old rats compared with 3- and 9-month-old rats. Expression of interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2, and inducible nitric oxide synthase increased. Each dose of saponins from Panax japonicus visibly suppressed microglial activation in the aging rat brain, and inhibited expression levels of the above factors. Each dose of saponins from Panax japonicus markedly diminished levels of nuclear factor kappa B, IκBα, extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38. These results confirm that saponins from Panax japonicus can mitigate neuroinflammation in the aging rat brain by inhibition of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways.

N-Acetylcysteine Amide Exerts Possible Neuroprotective Effects in Newborn Pigs after Perinatal Asphyxia

BACKGROUND

Perinatal asphyxia and ensuing reoxygenation change the antioxidant capacity of cells and organs.

OBJECTIVES

To analyze the neuroprotective effect of the antioxidant N-acetylcysteine amide (NACA) after perinatal hypoxia-reoxygenation with an emphasis on proinflammatory cytokines and the transcription factor NF-κB in the prefrontal cortex of neonatal pigs.

METHODS

Twenty-nine newborn pigs, aged 12-36 h, were subjected to global hypoxia and hypercapnia. One sham-operated group (n = 5) and 2 experimental groups (n = 12) were exposed to 8% oxygen, until the base excess was -20 mmol/l or the mean arterial blood pressure fell to <20 mm Hg (asphyxia with NACA or saline). The pigs were observed for 9.5 h after hypoxia. Samples of prefrontal cortex and plasma were analyzed.

RESULTS

Cortex: there was no significant difference in mRNA expression between the intervention groups regarding IL-1β, IL6, TNFα, MMP2, MMP9 or IL18. Pigs exposed to hypoxia-reoxygenation and treatment with NACA (NACA-pigs) had a significantly lower protein concentration of IL-1β than pigs treated with saline (placebo controls), i.e. 8.8 ± 3.9 versus 16.8 ± 10.5 pg/mg protein (p = 0.02). The activation of the transcription factor NF-κB (measured as the fold-change of phosphorylated p65Ser 536), was reduced in the NACA-pigs when compared to the placebo controls (5.2 ± 4.3 vs. 16.0 ± 13.5; p = 0.02). No difference between the intervention groups regarding brain histopathology or in the levels of 8-oxoguanine measured in the prefrontal cortex were observed. Plasma: the NACA-pigs had a stronger reduction of TNFα in the first 30 min following asphyxia compared with the placebo controls, i.e. 36 (30-44) versus 24 (14-32)% (p = 0.01).

CONCLUSION

The reduced levels of the pivotal inflammatory markers IL-1β and TNFα and the transcription factor NF-κB may indicate that NACA has possible neuroprotective effects after perinatal asphyxia.

Gene regulation and genetics in neurochemistry, past to future

Ask any neuroscientist to name the most profound discoveries in the field in the past 60 years, and at or near the top of the list will be a phenomenon or technique related to genes and their expression. Indeed, our understanding of genetics and gene regulation has ushered in whole new systems of knowledge and new empirical approaches, many of which could not have even been imagined prior to the molecular biology boon of recent decades. Neurochemistry, in the classic sense, intersects with these concepts in the manifestation of neuropeptides, obviously dependent upon the central dogma (the established rules by which DNA sequence is eventually converted into protein primary structure) not only for their conformation but also for their levels and locales of expression. But, expanding these considerations to non-peptide neurotransmitters illustrates how gene regulatory events impact neurochemistry in a much broader sense, extending beyond the neurochemicals that translate electrical signals into chemical ones in the synapse, to also include every aspect of neural development, structure, function, and pathology. From the beginning, the mutability - yet relative stability - of genes and their expression patterns were recognized as potential substrates for some of the most intriguing phenomena in neurobiology - those instances of plasticity required for learning and memory. Near-heretical speculation was offered in the idea that perhaps the very sequence of the genome was altered to encode memories. A fascinating component of the intervening progress includes evidence that the central dogma is not nearly as rigid and consistent as we once thought. And this mutability extends to the potential to manipulate that code for both experimental and clinical purposes. Astonishing progress has been made in the molecular biology of neurochemistry during the 60 years since this journal debuted. Many of the gains in conceptual understanding have been driven by methodological progress, from automated high-throughput sequencing instruments to recombinant-DNA vectors that can convey color-coded genetic modifications in the chromosomes of live adult animals. This review covers the highlights of these advances, both theoretical and technological, along with a brief window into the promising science ahead. This article is part of the 60th Anniversary special issue.

Therapies negating neuroinflammation after brain trauma

Traumatic brain injury (TBI) elicits a complex secondary injury response, with neuroinflammation as a crucial central component. Long thought to be solely a deleterious factor, the neuroinflammatory response has recently been shown to be far more intricate, with both beneficial and detrimental consequences depending on the timing, magnitude and specific immune composition of the response post-injury. Despite extensive preclinical and clinical research into mechanisms of secondary injury after TBI, no effective neuroprotective therapy has been identified, with potential candidates repeatedly proving disappointing in the clinic. The neuroinflammatory response offers a promising avenue for therapeutic targeting, aiming to quell the deleterious consequences without influencing its function in providing a neurotrophic environment supportive of repair. The present review firstly describes the findings of recent clinical trials that aimed to modulate inflammation as a means of neuroprotection. Secondly, we discuss promising multifunctional and single-target anti-inflammatory candidates either currently in trial, or with ample experimental evidence supporting clinical application. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Inflammatory cytokine receptor blockade in a rodent model of mild traumatic brain injury

In rodent models of traumatic brain injury (TBI), both Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNFα) levels increase early after injury to return later to basal levels. We have developed and characterized a rat mild fluid percussion model of TBI (mLFP injury) that results in righting reflex response times (RRRTs) that are less than those characteristic of moderate to severe LFP injury and yet increase IL-1α/β and TNFα levels. Here we report that blockade of IL-1α/β and TNFα binding to IL-1R and TNFR1, respectively, reduced neuropathology in parietal cortex, hippocampus, and thalamus and improved outcome. IL-1β binding to the type I IL-1 receptor (IL-1R1) can be blocked by a recombinant form of the endogenous IL-1R antagonist IL-1Ra (Kineret). TNFα binding to the TNF receptor (TNFR) can be blocked by the recombinant fusion protein etanercept, made up of a TNFR2 peptide fused to an Fc portion of human IgG1. There was no benefit from the combined blockades compared with individual blockades or after repeated treatments for 11 days after injury compared with one treatment at 1 hr after injury, when measured at 6 hr or 18 days, based on changes in neuropathology. There was also no further enhancement of blockade benefits after 18 days. Given that both Kineret and etanercept given singly or in combination showed similar beneficial effects and that TNFα also has a gliotransmitter role regulating AMPA receptor traffic, thus confounding effects of a TNFα blockade, we chose to focus on a single treatment with Kineret.

Curcumin prophylaxis mitigates the incidence of hypobaric hypoxia-induced altered ion channels expression and impaired tight junction proteins integrity in rat brain

Background

The present study was proposed to elucidate the prophylactic role of curcumin in the prevention of hypoxia-induced cerebral edema (HACE).

Methods

Rats were exposed to simulated hypobaric hypoxia at 7620 m for 24 h at 25 ± 1 °C. Transvascular leakage, expression of transcriptional factors (nuclear factor-kappa B (NF-κB) and hypoxia inducible factor 1 alpha (Hif-1α) and also the genes regulated by these transcriptional factors, sodium potassium-adenosine triphosphatase (Na⁺/K⁺-ATPase) and endothelial sodium channel (ENaC) levels and brain tight junction (TJ) proteins like ZO-1, junctional adhesion molecule C (JAMC), claudin 4 and claudin 5 levels were determined in the brain of rats under hypoxia by Western blotting, electro mobility shift assay, ELISA, immunohistochemistry, and histopathology along with haematological parameters. Simultaneously, to rule out the fact that inflammation causes impaired Na⁺/K⁺-ATPase and ENaC functions and disturbing the TJ integrity leading to cerebral edema, the rats were pre-treated with curcumin (100 mg/kg body weight) 1 h prior to 24-h hypoxia.

Results

Curcumin administration to rats, under hypoxia showed a significant decrease (p < 0.001) in brain water content (3.53 ± 0.58 wet-to-dry-weight (W/D) ratio) and transvascular leakage (136.2 ± 13.24 relative fluorescence units per gram (r.f.u./g)) in the brain of rats compared to control (24-h hypoxia) (7.1 ± 1.0 W/D ratio and 262.42 ± 24.67 r.f.u./g, respectively). Curcumin prophylaxis significantly attenuated the upregulation of NF-κB (p < 0.001), thereby leading to concomitant downregulation of pro-inflammatory cytokine levels (↓IL-1, IL-2, IL-18 and TNF-α), cell adhesion molecules (↓P-selectin and E-selectin) and increased anti-inflammatory cytokine (↑IL-10). Curcumin stabilized the brain HIF-1α levels followed by maintaining VEGF levels along with upregulated Na⁺/K⁺-ATPase and ENaC levels (p < 0.001) under hypoxia. Curcumin restored the brain ZO-1, JAMC, claudin 4 and claudin 5 levels (p < 0.001) under hypoxia. Histopathological observations revealed the absence of edema and inflammation in the brain of rats supplemented with curcumin.

Conclusions

These results indicate that curcumin is a potent drug in amelioration of HACE as it effectively attenuated inflammation as well as fluid influx by maintaining the tight junction proteins integrity with increased ion channels expression in the brain of rats under hypoxia.

The role of inflammation in perinatal brain injury

Inflammation is increasingly recognized as being a critical contributor to both normal development and injury outcome in the immature brain. The focus of this Review is to highlight important differences in innate and adaptive immunity in immature versus adult brain, which support the notion that the consequences of inflammation will be entirely different depending on context and stage of CNS development. Perinatal brain injury can result from neonatal encephalopathy and perinatal arterial ischaemic stroke, usually at term, but also in preterm infants. Inflammation occurs before, during and after brain injury at term, and modulates vulnerability to and development of brain injury. Preterm birth, on the other hand, is often a result of exposure to inflammation at a very early developmental phase, which affects the brain not only during fetal life, but also over a protracted period of postnatal life in a neonatal intensive care setting, influencing critical phases of myelination and cortical plasticity. Neuroinflammation during the perinatal period can increase the risk of neurological and neuropsychiatric disease throughout childhood and adulthood, and is, therefore, of concern to the broader group of physicians who care for these individuals.

Hypoxic preconditioning can reduce injury-induced inflammatory processes in the neonatal rat brain

Inflammation plays an important role in the pathophysiology of neonatal hypoxic-ischemic (HI) brain injury. Studies have shown that hypoxic preconditioning (HP) can ameliorate brain damage, but its effects on inflammation remain unknown. Postnatal day 6 (P6), Sprague-Dawley rats were divided into normoxia and hypoxia (8% oxygen, 3h) groups. On P7, some pups underwent a right carotid artery occlusion followed by hypoxia (8% oxygen, 3h) while under 1.5% isofluorane anesthesia and the remaining pups underwent sham surgery without occlusion. Animals were sacrificed 5 days later and fixed tissue was used to examine changes in neurons, astrocytes, and microglia in the cortex. Fresh tissue was collected to determine cortical levels of proinflammatory cytokines using ELISA. There was a significant loss in the number of NeuN positive cells in the cortex following HI injury, which was improved when HP was given prior to HI. There was an increase in cortical area of astrocyte staining after HI injury compared to control. HP before HI was able to reduce area of GFAP staining back to control levels. HI caused a large increase in the number of activated microglia compared to control and HP was able to significantly reduce this, although not back to control levels. HP alone increased microglial activation. Interleukin-1β levels were increased in the cortex 5 days after HI, but HP was not able to significantly reduce this change. The neuroprotective effects of HP appear to be mediated by affecting cellular inflammatory processes in the brain following HI injury.

Neuroprotective mechanism of Lycium barbarum polysaccharides against hippocampal-dependent spatial memory deficits in a rat model of obstructive sleep apnea

Chronic intermittent hypoxia (CIH) is a hallmark of obstructive sleep apnea (OSA), which induces hippocampal injuries mediated by oxidative stress. This study aims to examine the neuroprotective mechanism of Lycium barbarum polysaccharides (LBP) against CIH-induced spatial memory deficits. Adult Sprague–Dawley rats were exposed to hypoxic treatment resembling a severe OSA condition for a week. The animals were orally fed with LBP solution (1mg/kg) daily 2 hours prior to hypoxia or in air for the control. The effect of LBP on the spatial memory and levels of oxidative stress, inflammation, endoplasmic reticulum (ER) stress, apoptosis and neurogenesis in the hippocampus was examined. There was a significant deficit in the spatial memory and an elevated level of malondialdehyde with a decreased expression of antioxidant enzymes (SOD, GPx-1) in the hypoxic group when compared with the normoxic control. In addition, redox-sensitive nuclear factor kappa B (NFКB) canonical pathway was activated with a translocation of NFКB members (p65, p50) and increased expression levels of NFКB-dependent inflammatory cytokines and mediator (TNFα, IL-1β, COX-2); also, a significantly elevated level of ER stress (GRP78/Bip, PERK, CHOP) and autophagic flux in the hypoxic group, leading to neuronal apoptosis in hippocampal subfields (DG, CA1, CA3). Remarkably, LBP administration normalized the elevated level of oxidative stress, neuroinflammation, ER stress, autophagic flux and apoptosis induced by hypoxia. Moreover, LBP significantly mitigated both the caspase-dependent intrinsic (Bax, Bcl2, cytochrome C, cleaved caspase-3) and extrinsic (FADD, cleaved caspase-8, Bid) signaling apoptotic cascades. Furthermore, LBP administration prevented the spatial memory deficit and enhanced the hippocampal neurogenesis induced by hypoxia. Our results suggest that LBP is neuroprotective against CIH-induced hippocampal-dependent spatial memory deficits by promoting hippocampal neurogenesis and negatively modulating the apoptotic signaling cascades activated by oxidative stress and inflammation.

Tamoxifen reduces infiltration of inflammatory cells, apoptosis and inhibits IKK/NF-kB pathway after spinal cord injury in rats

In this study, neuroprotective effect of tamoxifen has been explored in spinal cord injury (SCI) in rats by examining factors influencing IKK/NF-kB pathway in SCI in rats. It has been shown in several studies that IKK/NF-kB signaling pathway plays a key role in pathophysiology of SCI. In this study, three groups of rats (n = 17 each) were selected that included, tamoxifen group (here tamoxifen was injected after SCI in rats), SCI group (here only dimethylsulfoxide was administered after inducing SCI in rats) and sham group (here only laminectomy was performed). The effect of tamoxifen (5 mg/kg) on various factors responsible for activation of IKK/NF-kB signaling pathway including NF-kB p65, phosphorylated I-kBα was studied through Western blotting as well as densitometry. The examination of expression of active caspase-3 and myeloperoxidase activity was also carried out through Western blot analysis and densitometry. A comparison of three groups of rats showed that administration of tamoxifen significantly reduced the expression of NF-kB p65 and phosphorylated I-kBα (P < 0.05) compared to control. It also attenuated the expression of active caspase-3 resulting in the reduction of apoptosis, and infiltration of leukocytes to the injury site was also greatly reduced in the group where tamoxifen was administered. Statistical analysis through SPSS 13.0 software showed a significant decrease in the expression of inflammatory factors in groups where tamoxifen was administered. We conclude that tamoxifen possesses the potential neuroprotective effects that can be explored further for future therapeutic techniques in treating spinal cord injuries.

Brain interleukin-1β and the intrinsic receptor antagonist control peripheral Toll-like receptor 3-mediated suppression of spontaneous activity in rats

During acute viral infections such as influenza, humans often experience not only transient fever, but also prolonged fatigue or depressive feelings with a decrease in social activity for days or weeks. These feelings are thought to be due to neuroinflammation in the brain. Recent studies have suggested that chronic neuroinflammation is a precipitating event of various neurological disorders, but the mechanism determining the duration of neuroinflammation has not been elucidated. In this study, neuroinflammation was induced by intraperitoneal injection of polyriboinosinic:polyribocytidylic acid (poly I:C), a Toll-like receptor-3 agonist that mimics viral infection in male Sprague-Dawley rats, and then investigated how the neuroinflammation shift from acute to the chronic state. The rats showed transient fever and prolonged suppression of spontaneous activity for several days following poly I:C injection. NS-398, a cyclooxygenase-2 inhibitor, completely prevented fever, but did not improve spontaneous activity, indicating that suppression of spontaneous activity was not induced by the arachidonate cascade that generated the fever. The animals overexpressed interleukin (IL)-1β and IL-1 receptor antagonist (IL-1ra) in the brain including the cerebral cortex. Blocking the IL-1 receptor in the brain by intracerebroventricular (i.c.v.) infusion of recombinant IL-1ra completely blocked the poly I:C-induced suppression of spontaneous activity and attenuated amplification of brain interferon (IFN)-α expression, which has been reported to produce fatigue-like behavior by suppressing the serotonergic system. Furthermore, i.c.v. infusion of neutralizing antibody for IL-1ra prolonged recovery from suppression of spontaneous activity. Our findings indicated that IL-1β is the key trigger of neuroinflammation and that IL-1ra prevents the neuroinflammation entering the chronic state.

Interleukin-1 receptor blockade in perinatal brain injury

Interleukin-1 (IL-1) is a potent inflammatory cytokine that can be produced by a variety of cell types throughout the body. While IL-1 is a central mediator of inflammation and response to infection, the role of IL-1 signaling in adult and pediatric brain injury is becoming increasingly clear. Although the mechanisms of IL-1 expression are largely understood, the downstream effects and contributions to excitotoxicity and oxidative stress are poorly defined. Here, we present a review of mechanisms of IL-1 signaling with a focus on the role of IL-1 in perinatal brain injury. We highlight research models of perinatal brain injury and the use of interleukin-1 receptor antagonist (IL-1RA) as an agent of therapeutic potential in preventing perinatal brain injury due to exposure to inflammation.

Inflammatory consequences in a rodent model of mild traumatic brain injury

Mild traumatic brain injury (mTBI), particularly mild "blast type" injuries resulting from improvised exploding devices and many sport-caused injuries to the brain, result in long-term impairment of cognition and behavior. Our central hypothesis is that there are inflammatory consequences to mTBI that persist over time and, in part, are responsible for resultant pathogenesis and clinical outcomes. We used an adaptation (1 atmosphere pressure) of a well-characterized moderate-to-severe brain lateral fluid percussion (LFP) brain injury rat model. Our mild LFP injury resulted in acute increases in interleukin-1α/β and tumor necrosis factor alpha levels, macrophage/microglial and astrocytic activation, evidence of heightened cellular stress, and blood-brain barrier (BBB) dysfunction that were evident as early as 3-6 h postinjury. Both glial activation and BBB dysfunction persisted for 18 days postinjury.

Transgenerational effects of neonatal hypoxia-ischemia in progeny

Neonatal hypoxia-ischemia (HI) affects 60% of low birth weight infants and up to 40% of preterm births. Cell death and brain injury after HI have been shown to cause long-lasting behavioral deficits. By using a battery of behavioral tests on second generation 3-week-old rodents, we found that neonatal HI is associated with behavioral outcomes in the progeny of HI-affected parents. Our results suggest an epigenetic transfer mechanism of some of the neurological symptoms associated with neonatal HI. Elucidating the transfer of brain injury to the next generation after HI calls attention to the risks associated with HI injury and the need for proper treatment to reverse these effects. Assessing the devastating extent of HI's reach serves as a cautionary tale to the risks associated with neonatal HI, and provides an incentive to create improved therapeutic measures to treat HI.

Modulation of Preactivation of PPAR-β on Memory and Learning Dysfunction and Inflammatory Response in the Hippocampus in Rats Exposed to Global Cerebral Ischemia/Reperfusion

The aim of this study is to investigate the neuroprotective effects and relevant mechanism of GW0742, an agonist of PPAR-β, after global cerebral ischemia-reperfusion injury (GCIRI) in rats. The rats showed memory and cognitive impairment and cytomorphological change in the hippocampus neurons following GCIRI. These effects were significantly improved by pretreatment with GW0742 in the dose-dependent manner. The expressions of IL-1β, IL-6, and TNF-α were increased after GCIRI, while the increases in these proinflammatory cytokines by GCIRI were inhibited by GW0742 pretreatment. Similarly, GW0742 pretreatment also improved the GCIRI-induced decrease in the expression of IL-10, which can act as an inhibitory cytokine to reduce cerebral ischemic injury. For another, NF-κB p65 expression was significantly increased in hippocampal neurons with apparent nuclear translocation after global cerebral IRI, and these phenomena were also largely attenuated by GW0742 pretreatment. Moreover, the mRNA and protein expressions of PPAR-β were significantly decreased in GCIRI + GW0742 groups when compared with those in GCIRI group. Our data suggests that the PPAR-β agonist GW0742 can exert significant neuroprotective effect against GCIRI in rats via PPAR-β activation and its anti-inflammation effect mediated by the inhibition of expression and activation of NF-κB in the hippocampus.

Quercetin as a prophylactic measure against high altitude cerebral edema

The present study was undertaken to elucidate the intervention of quercetin against high altitude cerebral edema (HACE) using male Sprague Dawley rats as an animal model. This study was also programmed to compare and correlate the effect of both quercetin (flavonoid) and dexamethasone (steroid) against HACE. Six groups of animals were designed for this experiment, (I) normoxia, (II) hypoxia (25,000 ft, 24 h), (III) normoxia+quercetin (50 mg/kg body wt), (IV) normoxia+dexamethasone (4 mg/kg body wt), (V) hypoxia+quercetin (50 mg/kg body wt), (VI) hypoxia+dexamethasone (4 mg/kg body wt). Quercetin at 50 mg/kg body wt, orally 1h prior to hypoxia exposure, was considered as the optimum dose, due to a significant reduction in the level of brain water content and cerebral transvascular leakage (P < 0.001), as compared to control (24 h hypoxia). Dexamethasone was administered at 4 mg/kg body wt, orally, 1h prior to hypoxia exposure. Both drugs (quercetin and dexamethasone) could efficiently reduce the hypoxia-induced hematological changes. Quercetin was observed to be a more potent antioxidative and anti-inflammatory agent. It blocks nuclear factor kappa-beta (NFκB) more significantly (P < 0.05) than the dexamethasone-administered hypoxia-exposed rats. Histopathological findings demonstrate the absence of an edema and inflammation in the brain sections of quercetin-administered hypoxia-exposed rats. The present study reveals quercetin to be a potent drug against HACE, as it efficiently attenuates inflammation as well as cerebral edema formation without any side effects of steroid therapy (dexamethasone).

In vivo intermittent hypoxia elicits enhanced expansion and neuronal differentiation in cultured neural progenitors

In vitro exposure of neural progenitor cell (NPC) populations to reduced O(2) (e.g. 3% versus 20%) can increase their proliferation, survival and neuronal differentiation. Our objective was to determine if an acute (<1hr), in vivo exposure to intermittent hypoxia (AIH) alters expansion and/or differentiation of subsequent in vitro cultures of NPC from the subventricular zone (SVZ). Neonatal C57BL/6 mice (postnatal day 4) were exposed to an AIH paradigm (20×1 minute; alternating 21% and 10% O(2)). Immediately after AIH, SVZ tissue was isolated and NPC populations were cultured and assayed either as neurospheres (NS) or as adherent monolayer cells (MASC). AIH markedly increased the capacity for expansion of cultured NS and MASC, and this was accompanied by increases in a proliferation maker (Ki67), MTT activity and hypoxia-inducible factor-1α (HIF-1α) signaling in NS cultures. Peptide blockade experiments confirmed that proteins downstream of HIF-1α are important for both proliferation and morphological changes associated with terminal differentiation in NS cultures. Finally, immunocytochemistry and Western blotting experiments demonstrated that AIH increased expression of the neuronal fate determination transcription factor Pax6 in SVZ tissue, and this was associated with increased neuronal differentiation in cultured NS and MASC. We conclude that in vivo AIH exposure can enhance the viability of subsequent in vitro SVZ-derived NPC cultures. AIH protocols may therefore provide a means to "prime" NPC prior to transplantation into the injured central nervous system.

Role of Bcl-3 in solid tumors

Bcl-3 is an established oncogene in hematologic malignancies, such as B-cell chronic lymphocytic leukemias. Nevertheless, recent research has shown that it also participates in progression of diverse solid tumors. The present review summarizes the current knowledge of Bcl3 role in solid tumors progression, including some new insights in its possible molecular mechanisms of action.

Evolution of β-Cell Replacement Therapy in Diabetes Mellitus: Islet Cell Transplantation

Diabetes mellitus remains one of the leading causes of morbidity and mortality worldwide. According to the Centers for Disease Control and Prevention, approximately 23.6 million people in the United States are affected. Of these individuals, 5 to 10% have been diagnosed with Type 1 diabetes mellitus (T1DM), an autoimmune disease. Although it often appears in childhood, T1DM may manifest at any age, leading to significant morbidity and decreased quality of life. Since the 1960s, the surgical treatment for diabetes mellitus has evolved to become a viable alternative to insulin administration, beginning with pancreatic transplantation. While islet cell transplantation has emerged as another potential alternative, its role in the treatment of T1DM remains to be solidified as research continues to establish it as a truly viable alternative for achieving insulin independence. In this paper, the historical evolution, procurement, current status, benefits, risks, and ongoing research of islet cell transplantation are explored.

Oxygen resuscitation after hypoxia ischemia stimulates prostaglandin pathway in rat cortex

Exposure to hypoxia and hyperoxia in a rodent model of perinatal ischemia results in delayed cell death and inflammation. Hyperoxia increases oxidative stress that can trigger inflammatory cascades, neutrophil activation, and brain microvascular injury. Here we show that 100% oxygen resuscitation in our rodent model of perinatal ischemia increases cortical COX-2 protein levels, S-nitrosylated COX-2cys526, PGE2, iNOS and 5-LOX, all components of the prostaglandin and leukotriene inflammatory pathway.

Oxygen resuscitation does not ameliorate neonatal hypoxia/ischemia-induced cerebral edema

Neonatal hypoxia/ischemia (HI) is a common cause of cognitive and behavioral deficits in children with hyperoxia treatment (HHI) being the current therapy for newborn resuscitation. HI induces cerebral edema that is associated with poor neurological outcomes. Our objective was to characterize cerebral edema after HI and determine the consequences of HHI (40% or 100% O(2)). Dry weight analyses showed cerebral edema 1 to 21 days after HI in the ipsilateral cortex; and 3 to 21 days after HI in the contralateral cortex. Furthermore, HI increased blood-brain barrier (BBB) permeability 1 to 7 days after HI, leading to bilateral cortical vasogenic edema. HHI failed to prevent HI-induced increase in BBB permeability and edema development. At the molecular level, HI increased ipsilateral, but not contralateral, AQP4 cortical levels at 3 and up to 21 days after HI. HHI treatment did not further affect HI-induced changes in AQP4. In addition, we observed developmental increases of AQP4 accompanied by significant reduction in water content and increase permeability of the BBB. Our results suggest that the ipsilateral HI-induced increase in AQP4 may be beneficial and that its absence in the contralateral cortex may account for edema formation after HI. Finally, we showed that HI induced impaired motor coordination 21 days after the insult and HHI did not ameliorate this behavioral outcome. We conclude that HHI treatment is effective as a resuscitating therapy, but does not ameliorate HI-induced cerebral edema and impaired motor coordination.

Normobaric hyperoximia increases hypoxia-induced cerebral injury: DTI study in rats

Perinatal hypoxia affects normal neurological development and can lead to motor, behavioral and cognitive deficits. A common acute treatment for perinatal hypoxia is oxygen resuscitation (hyperoximia), a controversial treatment. Magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI), was performed in a P7 rat model of perinatal hypoxia to determine the effect of hyperoximia. These studies were performed on two groups of animals: 1) animals which were subjected to ischemia followed by hypoxia (HI), and 2) HI followed by hyperoximic treatment (HHI). Lesion volumes on high resolution MRI and DTI derived measures, fractional anisotropy (FA), mean diffusivity (MD), and axial and radial diffusivities (lambda(l) and lambda(t), respectively) were measured in vivo one day, one week, and three weeks after injury. Most significant differences in the MRI and DTI measures were found at three weeks after injury. Specifically, three weeks after HHI injury resulted in significantly larger hyperintense lesion volumes (95.26 +/- 50.42 mm(3)) compared to HI (22.25 +/- 17.62 mm(3)). The radial diffusivity lambda(t) of the genu of corpus callosum was significantly larger in HHI (681 +/- 330 x 10(-6) mm(2)/sec) than in HI (486 +/- 96 x 10(-6) mm(2)/sec). Over all, most significant differences in all the DTI metrics (FA, MD, lambda(t), lambda(l)) at all time points were found in the corpus callosum. Our results suggest that treatment of perinatal hypoxia with normobaric oxygen does not ameliorate, but exacerbates damage.

Magnesium sulfate treatment alters fetal cerebellar gene expression responses to hypoxia

Prenatal perturbation of brain circulation and oxygenation is a leading cause of perinatal brain damage affecting about 0.3-0.9% of births. Hypoxia-ischemia (HI) in preterm human infants at gestational week 23-32 results in neurodevelopmental abnormalities in childhood, presenting as learning disability, seizure activity, motor impairment and in the most severe cases, death. Here, we examined the potential of MgSO4 treatment, prior to foetal hypoxia, to attenuate hypoxia induced damage in a murine model of maternal hypoxia. We studied the time course of maternal hypoxia and MgSO4 pre-treatment effects on cerebellar tissue by means of DNA microarray analyses. Mild hypoxia induced minor expression changes in most genes. However, there were 5 gene sets which were down-regulated by maternal hypoxia. MgSO4 pre-treatment abrogated these decreases in gene. A cell cycle gene set which responded immediately (2 h) to hypoxia, showed a delayed response (24 h) when MgSO4 pre-treatment was given. Similar proportions of cell death were observed in all groups before P7, where combined hypoxia and MgSO4 treatment increased cell death in the internal granule layer. There were a higher number of BrdU positive cells at the end of hypoxic episodes and a down-regulation of Reelin signaling, compared to control. MgSO4 pre-treatment prevented the enhancement of cell proliferation due to hypoxia and increased Reelin levels. Altogether, MgSO4 pre-treatment both reduced the number of genes differentially affected by hypoxia and delayed the responses to hypoxia. In addition, MgSO4 pre-treatment modified the nature of the transcriptional response; while hypoxia induced down-regulation of gene sets, MgSO4 pre-treatment mostly up-regulated them. The dual reaction to the MgSO4 treatment may be the source of the ambiguity in observations reported for affected newborns.

Impaired migration signaling in the hippocampus following prenatal hypoxia

Prenatal hypoxia ischemia is a major cause of neurodevelopmental impairment in the newborn, associated with risk for motor, behavioral and cognitive impaired outcomes. We used an established mouse model of maternal hypoxia to examine the immediate molecular responses of signaling pathways associated with both cell death and neurogenesis. We also characterized responses to maternal pre-treatment with MgSO(4). Maternal hypoxia at embryonic day 17 (E17) failed to trigger inflammation or cell death in fetal brain at 24 h after hypoxia. However, maternal hypoxia decreased levels of neuronal migration signaling: Reelin (53% of control), Disabled 1 (Dab1, 77% of control), and amyloid precursor protein (APP, 64% of control) 2 h after the insult. These changes persisted for 24 h. At later times, Reelin levels in hippocampi of newborns in the maternal hypoxia-treated group increased compared to controls. Full protection from maternal hypoxia effects on hippocampal Reelin levels resulted from maternal pre-treatment with MgSO(4). Hypoxia and MgSO(4) increased radial and lateral migration distance in the CA1 four days after the insult, while in the DG the hypoxia treatment alone increased migration. Maternal hypoxia and MgSO(4) pre-treatment also stimulated hippocampal expression of genes related to neurogenesis, such as BDNF and NeuroD4. Taken together, the long-term neurodevelopmental outcome of prenatal and perinatal hypoxia may depend on perturbation of developmental signals that affect neuronal migration.

Microarray analysis of high-dose recombinant erythropoietin treatment of unilateral brain injury in neonatal mouse hippocampus

Recombinant human erythropoietin (rEpo) is neuroprotective in neonatal models of brain injury. Proposed mechanisms of neuroprotection include activation of gene pathways that decrease oxidative injury, inflammation, and apoptosis, while increasing vasculogenesis and neurogenesis. To determine the effects of rEpo on gene expression in 10-d-old BALB-c mice with unilateral brain injury, we compared microarrays from the hippocampi of brain-injured pups treated with saline or rEpo to similarly treated sham animals. Total RNA was extracted 24 h after brain injury and analyzed using Affymetrix GeneChip Mouse Exon 1.0 ST Arrays. We identified sex-specific differences in hippocampal gene expression after brain injury and after high-dose rEpo treatment using single-gene and gene set analysis. Although high-dose rEpo had minimal effects on hippocampal gene expression in shams, at 24-h post brain injury, high-dose rEpo treatment significantly decreased the proinflammatory and antiapoptotic response noted in saline-treated brain-injured comparison animals.

Role of perinatal inflammation in cerebral palsy

Inflammatory molecules are promptly upregulated in the fetal environment and postnatally in brain-damaged subjects. Intrauterine infections and inflammation are often associated with asphyxia. This double-hit effect by combined infection or inflammation and hypoxia is therefore a frequent concomitant in neonatal brain damage. Animal models combining hypoxia and infection were recently designed to explore the mechanisms underlying brain damage in such circumstances and to look for possible neuroprotective strategies. Proinflammatory cytokines are thought to be major mediators in brain injury in neonates with perinatal asphyxia, bacterial infection, or both. Cytokines, however, could also have neuroprotective properties. The critical point in the balance between neurodamaging and neuroprotective effects of cytokines has yet to be unraveled. This understanding might help to develop new therapeutic approaches to counteract the inflammatory disequilibrium observed in the pathophysiologic mechanisms associated with brain injury.

Bax shuttling after neonatal hypoxia-ischemia: hyperoxia effects

Perinatal hypoxia-ischemia (HI) occurs in 0.2%-0.4% of all live births, with 100% O(2) resuscitation (HHI) remaining a standard clinical treatment. HI produces a broad spectrum of neuronal death phenotypes ranging from a more noninflammatory apoptotic death to a more inflammatory necrotic cell death that may be responsible for the broad spectrum of reported dysfunctional outcomes. However, the mechanisms that would account for this phenotypic spectrum of cell death are not fully understood. Here, we provide evidence that Bcl-2-associated X protein (Bax) can shuttle to different subcellular compartments in response to HI, thus triggering the different organelle-associated cell death signaling cascades resulting in cell death phenotype diversity. There was an early increase in intranuclear and total nuclear Bax protein levels followed by a later Bax redistribution to the mitochondria and endoplasmic reticulum (ER). Associated with the organelle-specific Bax shuttling time course, there was an increase in nuclear phosphorylated p53, cytosolic cleaved caspase-3, and caspase-12. When HI-treated P7 rats were resuscitated with 100% O(2) (HHI), there were increased lesion volumes as determined by T2-weighted magnetic resonance imaging with no change in cortical apoptotic signaling compared with HI treatment alone. There was, however, increased inflammatory (cytosolic-cleaved interleukin-1beta) and necrotic (increased nuclear 55-kDa-cleaved PARP-1 [poly-ADP-ribose 1] and decreased nuclear HMGB1 [nuclear high-mobility group box 1]) after HHI. Furthermore, HHI increased ER calpain activation and ER Bax protein levels compared with HI alone. These data suggest that 100% O(2) resuscitation increases Bax-mediated activation of ER cell death signaling, inflammation, and lesion volume by increasing necrotic-like cell death. In light of these findings, the use of 100% O(2) treatment for neonatal HI should be reevaluated.

Behavioral recovery from acute hypoxia is reliant on leptin

Individuals affected by hypoxia experience a variety of immune-associated sickness symptoms including malaise, fatigue, lethargy and loss of interest in the physical and social environment. Recently, we demonstrated that the interleukin (IL)-1beta arm of the neuroimmune system was critical to the sickness symptoms caused by hypoxia, and that IL-1 receptor antagonist (IL-1RA), IL-1beta's endogenous inhibitor, was critical to promoting sickness recovery. Here, we report that leptin is key to recovery from hypoxia because it dramatically augmented IL-1RA production in mice. We found that hypoxia increased leptin in white adipose tissue (WAT) which in turn, caused a marked rise in serum IL-1RA. Interestingly, in-vitro, leptin was a more potent inducer of IL-RA, in macrophages, than hypoxia. In leptin receptor defective (db/db) and leptin deficient (ob/ob) mice, sickness recovery from hypoxia was delayed 3-fold. Importantly, in ob/ob mice, leptin administration completely reversed this delayed recovery and induced a marked increase in serum IL-1RA. Finally, leptin administration to normal mice reduced hypoxia recovery time by 1/3 and dramatically increased WAT and serum IL-1RA. Leptin did not alter recovery from hypoxia in IL-1RA knock out mice. These results show that by enhancing IL-1RA production leptin promoted sickness recovery from hypoxia.