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Globins have been studied as model proteins to elucidate the principles of protein evolution. This was achieved by understanding the relationship between amino acid sequence, three-dimensional structure, physicochemical properties, and physiological function. Previous molecular phylogenies of chordate globin genes revealed the monophyletic evolution of urochordate globins and suggested convergent evolution. However, to provide evidence of convergent evolution, it is necessary to determine the physicochemical and functional similarities between vertebrates and urochordate globins. In this study, we determined the expression patterns of Ciona globin genes using real-time RT-PCR. Two genes (Gb-1 and Gb-2) were predominantly expressed in the branchial sac, heart, and hemocytes and were induced under hypoxia. Combined with the sequence analysis, our findings suggest that Gb-1/-2 correspond to vertebrate hemoglobin-α/-β. However, we did not find a robust similarity between Gb-3, Gb-4, and vertebrate globins. These results suggested that, even though Ciona globins obtained their unique functions differently from vertebrate globins, the two of them shared some physicochemical features and physiological functions. Our findings offer a good example for understanding the molecular mechanisms underlying gene co-option and convergence, which could lead to evolutionary innovations. [ABSTRACT FROM AUTHOR]

Mutant forms of human neuroglobin that carry targeted mutations in the putative interface with cytochrome c: single (E60K, K67E, E87K, K95E) and double (E60K\E87K) substitutions were obtained by site-directed mutagenesis. The E60K, K95E, and E60K\E87K mutations cause slight changes in the UV-vis absorption spectra, which can be associated with both a change in the electrostatic field near the heme and a change in the heme iron spin to the high-spin state. The secondary structure of mutant neuroglobins calculated from the CD spectral data almost did not differ from the secondary structure of wild-type neuroglobin, except for the protein with the K67E substitution, whose β-turn is reorganized into an α-helix. The IR spectra provide further evidence for the predominance of α-helices in protein secondary structure for mutant forms of neuroglobin. Thus, the introduction of these mutations did not have a significant effect on the characteristics of the heme-containing protein neuroglobin. The developed mutant forms will be used to study the contribution of individual amino acid residues to the formation of the reaction complex between neuroglobin and cytochrome c, which will allow rational design of drugs for the therapy of various diseases associated with neuronal death in the future. [ABSTRACT FROM AUTHOR]

The discovery of neuroglobin (Ngb), a brain- or neuron-specific member of the hemoglobin family, has revolutionized our understanding of brain oxygen metabolism. Currently, how Ngb plays such a role remains far from clear. Here, we report a novel mechanism by which Ngb might facilitate neuronal oxygenation upon hypoxia or anemia. We found that Ngb was present in, co-localized to, and co-migrated with mitochondria in the cell body and neurites of neurons. Hypoxia induced a sudden and prominent migration of Ngb towards the cytoplasmic membrane (CM) or cell surface in living neurons, and this was accompanied by the mitochondria. In vivo, hypotonic and anemic hypoxia induced a reversible Ngb migration toward the CM in cerebral cortical neurons in rat brains but did not alter the expression level of Ngb or its cytoplasm/mitochondria ratio. Knock-down of Ngb by RNA interference significantly diminished respiratory succinate dehydrogenase (SDH) and ATPase activity in neuronal N2a cells. Over-expression of Ngb enhanced SDH activity in N2a cells upon hypoxia. Mutation of Ngb at its oxygen-binding site (His64) significantly increased SDH activity and reduced ATPase activity in N2a cells. Taken together, Ngb was physically and functionally linked to mitochondria. In response to an insufficient oxygen supply, Ngb migrated towards the source of oxygen to facilitate neuronal oxygenation. This novel mechanism of neuronal respiration provides new insights into the understanding and treatment of neurological diseases such as stroke and Alzheimer's disease and diseases that cause hypoxia in the brain such as anemia. [ABSTRACT FROM AUTHOR]

Neuroglobin, which is a heme protein from the globin family that is predominantly expressed in nervous tissue, can promote a neuronal survivor. However, the molecular mechanisms underlying the neuroprotective function of Ngb remain poorly understood to this day. The interactions between neuroglobin and mitochondrial cytochrome c may serve as at least one of the mechanisms of neuroglobin-mediated neuroprotection. Interestingly, neuroglobin and cytochrome c possibly can interact with or without electron transfer both in the cytoplasm and within the mitochondria. This review provides a general picture of molecular interactions between neuroglobin and cytochrome c based on the recent experimental and computational work on neuroglobin and cytochrome c interactions. [ABSTRACT FROM AUTHOR]

Cerebral ischemia/reperfusion (I/R) injury remains a grievous health threat, and herein effective therapy is urgently needed. This study explored the protection of neuroglobin (Ngb) in rats with cerebral I/R injury. The focal cerebral I/R rat models were established by middle cerebral artery occlusion (MCAO) and neuronal injury models were established by oxygen–glucose deprivation/reoxygenation (OGD/R) treatment. The brain injury of rats was assessed. Levels of Ngb, Bcl‐2, Bax, endoplasmic reticulum stress (ERS)‐related markers, and Syt1 were measured by immunofluorescence staining and Western blotting. The cytotoxicity in neurons was assessed by lactate dehydrogenase (LDH) release assay. Levels of intracellular Ca2+ and mitochondrial function‐related indicators were determined. The binding between Ngb and Syt1 was detected by co‐immunoprecipitation. Ngb was upregulated in cerebral I/R rats and its overexpression alleviated brain injury. In OGD/R‐induced neurons, Ngb overexpression decreased LDH level and neuronal apoptosis, decreased Ca2+ content, and mitigated mitochondrial dysfunction and ERS‐related apoptosis. However, Ngb silencing imposed the opposite effects. Importantly, Ngb could bind to Syt1. Syt1 knockdown partially counteracted the alleviation of Ngb on OGD/R‐induced injury in neurons and cerebral I/R injury in rats. Briefly, Ngb extenuated cerebral I/R injury by repressing mitochondrial dysfunction and endoplasmic reticulum stress‐mediated neuronal apoptosis through Syt1. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a debilitating neurodegenerative disease characterised by the accumulation of amyloid-beta and tau in the brain, leading to the progressive loss of memory and cognition. The causes of its pathogenesis are still not fully understood, but some risk factors, such as age, genetics, and hormones, may play a crucial role. Studies show that postmenopausal women have a higher risk of developing AD, possibly due to the decrease in hormone levels, especially oestrogen, which may be directly related to a reduction in the activity of oestrogen receptors, especially beta (ERβ), which favours a more hostile cellular environment, leading to mitochondrial dysfunction, mainly affecting key processes related to transport, metabolism, and oxidative phosphorylation. Given the influence of hormones on biological processes at the mitochondrial level, hormone therapies are of clinical interest to reduce the risk or delay the onset of symptoms associated with AD. One drug with such potential is tibolone, which is used in clinics to treat menopause-related symptoms. It can reduce amyloid burden and have benefits on mitochondrial integrity and dynamics. Many of its protective effects are mediated through steroid receptors and may also be related to neuroglobin, whose elevated levels have been shown to protect against neurological diseases. Its importance has increased exponentially due to its implication in the pathogenesis of AD. In this review, we discuss recent advances in tibolone, focusing on its mitochondrial-protective effects, and highlight how valuable this compound could be as a therapeutic alternative to mitigate the molecular pathways characteristic of AD. [ABSTRACT FROM AUTHOR]

Current management of glaucomatous optic neuropathy is limited to intraocular pressure control. Neuroglobin (Ngb) is an endogenous neuroprotectant expressed in neurons and astrocytes. We recently showed that exogenous intravitreal Ngb reduced inflammatory cytokines and microglial activation in a rodent model of hypoxia. We thus hypothesised that IVT-Ngb may also be neuroprotective in experimental glaucoma (EG) by mitigating optic nerve (ON) astrogliosis and microgliosis as well as structural damage. In this study using a microbead-induced model of EG in six Cynomolgus primates, optical coherence imaging showed that Ngb-treated EG eyes had significantly less thinning of the peripapillary minimum rim width, retinal nerve fibre layer thickness, and ON head cupping than untreated EG eyes. Immunohistochemistry confirmed that ON astrocytes overexpressed Ngb following Ngb treatment. A reduction in complement 3 and cleaved-caspase 3 activated microglia and astrocytes was also noted. Our findings in higher-order primates recapitulate the effects of neuroprotection by Ngb treatment in rodent EG studies and suggest that Ngb may be a potential candidate for glaucoma neuroprotection in humans. [ABSTRACT FROM AUTHOR]

An efficient system for the biosynthesis, isolation and purification of recombinant human neuroglobin has been developed and optimized, which makes it possible to produce protein in quantities sufficient to study its properties. According to UV-visible, IR-, CD-, and NMR spectroscopy data, recombinant neuroglobin is a structured protein in the holoform state. The data of chromato-mass-spectrometric analysis made it possible to conclude that there is a correctly formed disulfide bond in the structure of the oxidized form of the protein. Using Raman and surface-enhanced Raman spectroscopy with laser excitation at 532 nm, it was shown that heme in the reduced and oxidized forms of neuroglobin has vibrational degrees of freedom typical of b-type hemes, and the iron atom is hexacoordinated. Using Raman spectroscopy with laser excitation at 633 nm, it was found that reduced –SH-groups were present in reduced neuroglobin, while in oxidized neuroglobin a disulfide bridge was formed. The results obtained serve as the basis for detailed studies of the functioning of neuroglobin as a neuroprotector, in particular, during its interaction with oxidized cytochrome c, which is released from mitochondria in violation of their functioning and/or morphology. [ABSTRACT FROM AUTHOR]

In the present study, human neuroglobin (hNgb) was found to undergo H2O2‐induced breakdown of the heme center at a much slower rate than other globins, namely in the timescale of hours against minutes. We investigated how the rate of the process is affected by the Cys46/Cys55 disulfide bond and the network of non‐covalent interactions in the distal heme side involving Tyr44, Lys67, the His64 heme iron axial ligand and the heme propionate‐7. The rate is increased by the Tyr44 to Ala and Phe mutations; however the rate is lowered by Lys67 to Ala swapping. The absence of the disulfide bridge slows down the reaction further. Therefore, the disulfide bond‐controlled accessibility of the heme site and the residues at position 44 and 67 affect the activation barrier of the reaction. Wild‐type and mutated species form β‐amyloid aggregates in the presence of H2O2 producing globular structures. Furthermore, the C46A/C55A, Y44A, Y44F and Y44F/C46A/C55A variants yield potentially harmful fibrils. Finally, the nucleation and growth kinetics for the aggregation of the amyloid structures can be successfully described by the Finke–Watzky model. [ABSTRACT FROM AUTHOR]

Background and Purpose: Intracerebral and subarachnoid hemorrhage are critical conditions with a high mortality, and the outcome for the individual patient is notoriously difficult to predict. Biomarkers that reflect disease severity and predict outcome are therefore warranted.Methods: Blood samples from 40 patients with intracerebral, 46 patients with subarachnoid hemorrhage, and 70 healthy individuals were collected. Levels of glial fibrillary acidic protein (GFAP) and neuroglobin were measured by ultra-sensitive single molecule array and enzyme-linked immunosorbent assay, respectively. Clinical information including mortality and functional outcome was recorded.Results: Blood levels of GFAP and neuroglobin in intracerebral and subarachnoid hemorrhage patients were significantly elevated when compared to healthy individuals (all p < 0.0001). GFAP levels were significantly higher in patients dying or with poor functional outcome than in healthy individuals (all p ≤ 0.01). GFAP levels separated survivors from non-survivors with an area under receiver operating characteristics (AUROC) = 0.78 (confidence interval (CI) 0.59-0.98) for intracerebral hemorrhage and 0.82 (CI 0.69-0.94) for subarachnoid hemorrhage patients. The Akaike and Bayesian information criteria (AIC/BIC) for mortality/poor outcome prediction improved when combining GFAP levels with hematoma volume (p = 0.04/p < 0.01), National Institutes of Health Stroke Scale (NIHSS) (p = 0.09/p < 0.01), Hunt-Hess (p < 0.05/p = 0.21), or Fischer score (p < 0.05/p = 0.02).Conclusions: Elevated GFAP levels at admission to hospital predicted mortality and poor outcome in our cohort of intracerebral and subarachnoid hemorrhage patients. Neuroglobin levels did not provide additional information. Combining GFAP measurements with clinical disease severity scores increased outcome prediction precision. This may suggest that GFAP measurement could improve prognostication in patients with intracerebral or subarachnoid hemorrhage.Registration: This sub-trial was not registered. [ABSTRACT FROM AUTHOR]

We present a comprehensive investigation on the different role of CO in carboxyneuroglobin (1) as ligand of the heme group in the active site forming a bond with the heme iron and (2) dissociated from the heme group but still trapped inside the active site, focusing on two specific orientations, one with CO perpendicular to the plane defined by the distal histidine of the enzyme (form A) and one with CO located parallel to that plane (form B). Our study includes wild type carboxy‐neuroglobin and nine known protein mutations. Considering that the distal histidine interacting with the heme group can adapt two different tautomeric forms and the two possible orientations of the dissociated CO, a total of 36 protein systems were analyzed in this study. Fully optimized geometries and vibrational frequencies were calculated at the QM/MM level, followed by the local mode analysis, to decode CO bond properties. The intrinsic bond strengths derived from the local mode analysis, complemented with NBO and QTAIM data, reveal that the strength of the CO bond, in the hexacoordinate (where CO is a ligand of the heme group) and pentacoordinate (where CO is dissociated from the heme group) scenarios, is dominated by through bond and through space charge transfer between CO and Fe, fine‐tuned by electrostatic and dispersion interactions with the side chain amino acids in the distal heme pocket. Suggestions are made as to advise on how protein modifications can influence the molecular properties of the coordinated or dissociated CO, which could serve the fine‐tuning of existing and the design of new neuroglobin models with specific FeC and CO bond strengths. [ABSTRACT FROM AUTHOR]

The present work shows the biochemical and structural fundamentals for the stress induced anxiety and stress adjustment response of the CA3 hippocampus area. Adult male Wistar rats were repeatedly exposed to a 3 h day restraint stress, for either 3 or 6 days. The concentration of corticosterone and testosterone in the CA3 hippocampus area was divergent, while oxidative stress was progressively increased during the stress exposure. The mitochondrial lysis in the CA3 neurons confirmed the oxidative stress events. Immunohistochemical findings showed that oligodendrocytes (OCs) proliferation and neuroglobin (Ngb) expression were stimulated, whereas MeCP2 expression was decreased as a balance reaction in stress exposure under corticosterone signaling. Remarkably, ultrastructural changes such as mitochondrial lysis, endoplasmic reticulum swelling, and perivascular lysis with platelets adherence to endothelium in the CA3 area were seen in the 6th day of restraining. The anxiety-like behavior was noticed 6 days later after stress exposure. These results suggest that the duration of the exposure, but not the intensity of the stress, is the key factor in the stress-buffering function by the CA3 hippocampus area via up-regulation of the Ngb-OCs bionome. The imbalance of the Ngb-OCs communication may be involved in the development of CA3-dependent anxious behavior. [ABSTRACT FROM AUTHOR]

Background/Aim: The brain uses 20% of the O2 consumed by the body for energy metabolism. In 2000, found a protein that is thought to be a binding O2 in the brain, namely neuroglobin (Ngb). Ngb is a member of the hemoprotein which has a heme group. The iron ion in the haem group can be oxidized, so a reducing enzyme is needed. In this study, the isolation, purification, and characterization of Ngb protein and the reducing enzyme from oxidized neuroglobin (neuroglobin Fe3+) were carried out. Materials and methods: Ngb protein was isolated by fractionation technique using ammonium sulfate 90% saturation, purified by anion exchange chromatography (DEAE Cellulose) and immunoaffinity chromatography, confirmed by SDS-PAGE and Western blot. The metneuroglobin-reducing enzyme was isolated by RIPA lysis buffer, purified by Affi gel blue chromatography, and confirmed by SDS-PAGE. Results: The isolated Ngb obtained has a molecular weight of 17.26 kDa. Spectrum analysis in the wavelength range of 350- 500nm, showed the afternoon peaks of deoxyNgb, oxyNgb, carboxyNgb and metNgb were 415 nm, 405 nm, 405 nm, and 420 nm, respectively. The results of the isolation of the reducing enzymes obtained consisted of 2 parts, namely the matrix-bound eluate (eluate-1) and matrix-bound eluate (eluate-2). SDS-PAGE results of eluate-1, eluate-2 and Ngb-free fraction (byproduct of Ngb purification) showed the same 3 bands at a molecular weight of 72.45; 26.84 and 16.33 kDa were suspected as reducing enzymes. Conclusion: The reduction kinetics was tested by reacting the fraction and metNgb and measuring the deoxyNgb uptake formed per unit time. The results of the measurement of the ratio of NgbFe3+ to NgbFe2+ from the free fractions Ngb, eluate-1 and eluate-2, which has the best reducing activity is eluate-1 because it has the best regression value of 0.8769. [ABSTRACT FROM AUTHOR]

Stroke is a global health and socio-economic problem. However, no efficient preventive and/or palliative treatments have yet been found. Neuroglobin (Ngb) is an endogen neuroprotective protein, but it only exerts its beneficial action against stroke after increasing its basal levels. Therefore, its systemic administration appears to be an efficient therapy applicable to stroke and other neurodegenerative pathologies. Unfortunately, Ngb cannot cross the blood-brain barrier (BBB), making its direct pharmacological use unfeasible. Thus, the association of Ngb with a drug delivery system (DDS), such as nanoparticles (NPs), appears to be a good strategy for overcoming this handicap. NPs are a type of DDS which efficiently transport Ngb and increase its bioavailability in the infarcted area. Hence, we previously built hyaluronate NPS linked to Ngb (Ngb-NPs) as a therapeutic tool against stroke. This nanoformulation induced an improvement of the cerebral infarct prognosis. However, this innovative therapy is still in development, and a more in-depth study focusing on its long-lasting neuroprotectant and neuroregenerative capabilities is needed. In short, this review aims to update the state-of-the-art of stroke therapies based on Ngb, paying special attention to the use of nanotechnological drug-delivering tools. [ABSTRACT FROM AUTHOR]

Most neurodegenerative diseases such as Alzheimer's disease are proteinopathies linked to the toxicity of amyloid oligomers. Treatments to delay or cure these diseases are lacking. Using budding yeast, we report that the natural lipid tripentadecanoin induces expression of the nitric oxide oxidoreductase Yhb1 to prevent the formation of protein aggregates during aging and extends replicative lifespan. In mammals, tripentadecanoin induces expression of the Yhb1 orthologue, neuroglobin, to protect neurons against amyloid toxicity. Tripentadecanoin also rescues photoreceptors in a mouse model of retinal degeneration and retinal ganglion cells in a Rhesus monkey model of optic atrophy. Together, we propose that tripentadecanoin affects p‐bodies to induce neuroglobin expression and offers a potential treatment for proteinopathies and retinal neurodegeneration. [ABSTRACT FROM AUTHOR]

Introduction: Traumatic spinal cord injury (TSCI) is a life-threatening neurological disorder and there is a lack of biomarker research, particularly human studies that could help to categorize the severity and predict the outcome. We aimed to assess the role of serum Ubiquitin C-terminal hydrolase L1 (UCH-L1) and Neuroglobin (NGB) in predicting severity and outcome of TSCI. Methods: This prospective study included 63 participants categorized into 33 patients with various types of TSCI and 30 unrelated healthy volunteers. Neurosurgical [American spinal injury association (ASIA) impairment score (AIS)] and radiological [using spine computed tomography (CT) and magnetic resonance imaging (MRI)] assessments were performed on the included patients to determine the severity and the level of injury with neurological follow-up of patients within 6 months post-injury. Serum UCH-L1 and NGB were measured for all participants using commercially available ELISA assay kits. Results: Of the included patients, 20 (60.60%) had partial SCI and the remaining 13 patients (39.39%) had complete SCI. On follow-up, 19 patients (57.57%) showed improved AIS, while 14 cases (42.42%) did not show any improvement in their AIS scores. There was significantly higher median serum UCHL1 value among cases compared to controls (1723 pg/mL and 657 pg/mL, respectively), p ˂ 0.05. There was an insignificant rise of serum NGB levels among cases in comparison with the controls (15.2pg/mL and 7.52pg/mL, respectively, p ˃ 0.05). Significantly lower initial median serum UCHL1 levels (pg/mL) were observed in patients with improved AIS during the neurological follow-up compared with those who did not show any improvement in their AIS score (1723, and 4700 respectively, p ˂ 0.05), with lack of significant difference in the initial median serum NGB levels, p ˃ 0.05. Conclusion: Initial serum UCHL1 assay could be a helpful marker in reflecting the degree of TSCI and predicting its outcome, though NGB needs further assessment. [ABSTRACT FROM AUTHOR]

Background: Neuroglobin (Ngb) is the fourth member of globin family which was found to be highly expressed in central and peripheral nervous system of humans. Overexpression of neuroglobin is strongly related to a neuroprotective function. Aim of the Study: Primary aim: to detect the levels of neuroglobin in children with Epilepsy Compared to Normal healthy Controls. Secondary aim: To compare the level of neuroglobin in controlled and uncontrolled epilepsy. Subject and Method: The study is controlled cross sectional study which was conducted on 85 children divided into three groups: group (I) included 30 children with controlled epilepsy, group (II) included 30 children with uncontrolled epilepsy, and group (III) included 25 healthy children selected as controls of matched gender and age. Serum Ngb assay, complete blood count (CBC) were performed to all children. Results: The overall results show that serum neuroglobin levels were significantly increased in patients' groups than in controls. Neuroglobin levels showed no significant difference between controlled epilepsy group and uncontrolled epilepsy one. Conclusion: Higher serum neuroglobin levels among children with epilepsy whether controlled or uncontrolled, reflecting its role as a neuroprotective marker. This study may help to discovernewer antiepileptic therapy through acting on neuroglobin levels. [ABSTRACT FROM AUTHOR]

Human neuroglobin (Ngb) contains a heme group and three Cys residues (Cys46, Cys55, and Cys120) in the polypeptide chain. By introducing an additional Cys at position 15, the X‐ray structure of A15C Ngb mutant was solved at a high resolution of 1.35 Å, which reveals the formation of both the native (C46C55) and the engineered (C15C120) disulfide bonds, likely playing a functional and structural role, respectively, according to the geometry analysis. Unexpectedly, 1,4‐dioxane from the crystallization reagents was bound not only to the protein surface, but also to the heme distal pocket, providing insights into protein‐ligand interactions for the globin and guiding the design of functional heme enzymes. [ABSTRACT FROM AUTHOR]

Nitric Oxide (NO) is a free radical with numerous critical signaling roles in vertebrate physiology. Similar to mammals, in the teleost system the generation of sufficient amounts of NO is critical for the physiological function of the cardiovascular system. At the same time, NO amounts are strictly controlled and kept within basal levels to protect cells from NO toxicity. Changes in oxygen tension highly influence NO bioavailability and can modulate the mechanisms involved in maintaining the NO balance. While NO production and signaling appears to have general similarities with mammalian systems, the wide range of environmental adaptations made by fish, particularly with regards to differing oxygen availabilities in aquatic habitats, creates a foundation for a variety of in vivo models characterized by different implications of NO production and signaling. In this review, we present the biology of NO in the teleost cardiovascular system and summarize the mechanisms of NO production and signaling with a special emphasis on the role of globin proteins in NO metabolism. [ABSTRACT FROM AUTHOR]

Objective: Stroke is closely related to dementia, but there are few prospective studies on cognitive decline after stroke in patients with cerebral hemorrhage. Neuroglobin is an oxygen-binding protein mainly expressed in brain neurons. The aim of our current study was to determine whether neuroglobin could serve as a biomarker for cognitive prognosis in patients with intracerebral hemorrhage (ICH). Methods: Three hundred and sixteen patients with ICH were consecutively enrolled in a prospective study. Baseline data such as age and gender of ICH patients on admission were recorded. Serum neuroglobin concentrations were determined by enzyme-linked immunosorbent assay (ELISA). All ICH patients 3 months after onset were divided into post-stroke cognitive impairment group (PSCI) and non-PSCI group according to MoCA assessment results. Results: The PSCI and Non-PSCI groups had serum neuroglobin concentrations of (4.7 ± 0.9) and (7.5 ± 1.1) ng/ml, respectively, with a statistically significant difference between the two groups (p < 0.05). Age, gender, LDL, FBG, SBP, DBP, NHISS, and Hematoma volume were found to be adversely connected with MoCA (p < 0.05), while education, HDL, and serum neuroglobin were found to be positively correlated with MoCA (p < 0.05). After controlling for baseline data, regression analysis revealed that serum neuroglobin was remained an efficient biomarker for predicting cognitive performance in individuals with ICH (p < 0.05). The diagnostic accuracy of blood neuroglobin concentration for PSCI in ICH patients was 72.6%, the sensitivity was 67.4%, and the specificity was 75.5%, according to receiver operating characteristic (ROC) curve analysis. Conclusions: Serum neuroglobin may serve as a potential biomarker to predict cognitive decline after ICH. [ABSTRACT FROM AUTHOR]

Microglia are the immune competent cell of the central nervous system (CNS), promoting brain homeostasis and regulating inflammatory response against infection and injury. Chronic or exacerbated neuroinflammation is a cause of damage in several brain pathologies. Endogenous carbon monoxide (CO), produced from the degradation of heme, is described as anti-apoptotic and anti-inflammatory in several contexts, including in the CNS. Neuroglobin (Ngb) is a haemoglobin-homologous protein, which upregulation triggers antioxidant defence and prevents neuronal apoptosis. Thus, we hypothesised a crosstalk between CO and Ngb, in particular, that the anti-neuroinflammatory role of CO in microglia depends on Ngb. A novel CO-releasing molecule (ALF826) based on molybdenum was used for delivering CO in microglial culture. BV-2 mouse microglial cell line was challenged with lipopolysaccharide (LPS) for triggering inflammation, and after 6 h ALF826 was added. CO exposure limited inflammation by decreasing inducible nitric oxide synthase (iNOS) expression and the production of nitric oxide (NO) and tumour necrosis factor-α (TNF-α), and by increasing interleukine-10 (IL-10) release. CO-induced Ngb upregulation correlated in time with CO's anti-inflammatory effect. Moreover, knocking down Ngb reversed the anti-inflammatory effect of CO, suggesting that dependents on Ngb expression. CO-induced Ngb upregulation was independent on ROS signalling, but partially dependent on the transcriptional factor SP1. Finally, microglial cell metabolism is also involved in the inflammatory response. In fact, LPS treatment decreased oxygen consumption in microglia, indicating a switch to glycolysis, which is associated with a proinflammatory. While CO treatment increased oxygen consumption, reverting LPS effect and indicating a metabolic shift into a more oxidative metabolism. Moreover, in the absence of Ngb, this phenotype was no longer observed, indicating Ngb is needed for CO's modulation of microglial metabolism. Finally, the metabolic shift induced by CO did not depend on alteration of mitochondrial population. In conclusion, neuroglobin emerges for the first time as a key player for CO signalling against exacerbated inflammation in microglia. [ABSTRACT FROM AUTHOR]

Prunus cerasoides (PC) has been reported to have antimicrobial and anti-inflammatory properties, but its potential as a neuroprotective agent in a mouse model of cerebral ischemia has not been explored. Considering neuroglobin (Ngb), an endogenous neuroprotective factor, as a novel approach to neuroprotection, in this study, Ngb promoter activity, Ngb expression changes, and antioxidant protection by PC extract (PCE) and PC component compounds (PCCs) were analyzed in oxygen– glucose deprivation (OGD)-treated neurons. In vivo analysis involved transient middle cerebral artery occlusion (tMCAO) in mice with pre- and post-treatment exposure to PCE. Following ischemic stroke induction, neurological behavior scores were obtained, and cellular function-related signals were evaluated in the ischemic infarct areas. In addition to PCE, certain component compounds from PCE also significantly increased Ngb levels and attenuated the intracellular ROS production and cytotoxicity seen with OGD in primary neurons. Administration of PCE reduced the infarct volume and improved neurological deficit scores in ischemic stroke mice compared with the vehicle treatment. Increased Ngb levels in infarct penumbra with PCE treatment were also accompanied by decreased markers of apoptosis (activated p38 and cleaved caspase-3). Our findings point to the benefits of Ngb-mediated neuroprotection via PCE and its antioxidant activity in an ischemic stroke model. [ABSTRACT FROM AUTHOR]

Prunus cerasoides (PC) has been reported to have antimicrobial and anti-inflammatory properties, but its potential as a neuroprotective agent in a mouse model of cerebral ischemia has not been explored. Considering neuroglobin (Ngb), an endogenous neuroprotective factor, as a novel approach to neuroprotection, in this study, Ngb promoter activity, Ngb expression changes, and antioxidant protection by PC extract (PCE) and PC component compounds (PCCs) were analyzed in oxygen– glucose deprivation (OGD)-treated neurons. In vivo analysis involved transient middle cerebral artery occlusion (tMCAO) in mice with pre- and post-treatment exposure to PCE. Following ischemic stroke induction, neurological behavior scores were obtained, and cellular function-related signals were evaluated in the ischemic infarct areas. In addition to PCE, certain component compounds from PCE also significantly increased Ngb levels and attenuated the intracellular ROS production and cytotoxicity seen with OGD in primary neurons. Administration of PCE reduced the infarct volume and improved neurological deficit scores in ischemic stroke mice compared with the vehicle treatment. Increased Ngb levels in infarct penumbra with PCE treatment were also accompanied by decreased markers of apoptosis (activated p38 and cleaved caspase-3). Our findings point to the benefits of Ngb-mediated neuroprotection via PCE and its antioxidant activity in an ischemic stroke model. [ABSTRACT FROM AUTHOR]

Neuroglobin (Ngb) was recently identified as a member of the vertebrate hemoglobin family. Several studies have been conducted on Ngb in mammals, but none have compared its expression and localization among different mammals. This review compared the distribution and localization of Ngb expression and explained the different functions of Ngb in the brains of mammals. Intel's integrated performance primitive (IPP) analysis was employed to obtain the expression levels in each region of the mammalian brain. Ngb is widely expressed in the adult yak brain and distributed in different areas, similar to its expression in cattle. The relative expression of the Ngb gene in the cerebral cortex (262.69±9.19) was significantly higher than that in the cerebellar cortex (137.00±7.29), hippocampus (1.00±0.22), medulla oblongata (3.43±0.76), striatum (7.65±0.61) and olfactory bulb (2.14±1.22). Findings in the rat brain showed low Ngb protein expression. The mouse brain showed Ngb over expression in a transgenic variant (Ngb-Tg), while in the human brain, the level of Ngb was higher in the hypothalamus, amygdala and pontine tegmental nuclei than in other parts of the brain. The expression levels, distribution and localization of Ngb differ across the brains of different mammals, so it is appropriate to explore the precise distribution and localization of Ngb before comparison or analysis in these mammals. [ABSTRACT FROM AUTHOR]

In humans, a considerable number of the autopsy samples of cognitively normal individuals aged between 57 and 102 years have revealed the presence of amyloid plaques, one of the typical signs of AD, indicating that many of us use mechanisms that defend ourselves from the toxic consequences of Aß. The human APP NL/F (hAPP NL/F) knockin mouse appears as the ideal mouse model to identify these mechanisms, since they have high Aß42 levels at an early age and moderate signs of disease when old. Here we show that in these mice, the brain levels of the hemoprotein Neuroglobin (Ngb) increase with age, in parallel with the increase in Aß42. In vitro , in wild type neurons, exogenous Aß increases the expression of Ngb and Ngb over-expression prevents Aß toxicity. In vivo , in old hAPP NL/F mice, Ngb knockdown leads to dendritic tree simplification, an early sign of Alzheimer's disease. These results could indicate that Alzheimer's symptoms may start developing at the time when defense mechanisms start wearing out. In agreement, analysis of plasma Ngb levels in aged individuals revealed decreased levels in those whose cognitive abilities worsened during a 5-year longitudinal follow-up period. [ABSTRACT FROM AUTHOR]

The study investigated the potential neuroprotective effects of metformin (MET) on alcohol-induced neurotoxicity in adult Wistar rats. The animals were randomized in four groups (n = 10): control, alcohol (ALC), ALC + MET, and MET. ALC (2 g/kg b.w.) and MET (200 mg/kg b.w.) were orally administered for 21 days, once daily. For the ALC + MET group, MET was administered 2 h after ALC treatment. On day 22, the open field test (OFT) and elevated plus maze (EPM) were performed. MET improved global activity and increased the time spent in unprotected open arms, decreased oxidative stress, both in the frontal lobe and in the hippocampus, and increased neuroglobin expression in the frontal cortex. Histopathologically, an increased neurosecretory activity in the frontal cortex in the ALC + MET group was noticed. Thus, our findings suggest that metformin has antioxidant and anxiolytic effects and may partially reverse the neurotoxic effects induced by ethanol. [ABSTRACT FROM AUTHOR]

Background: Exploring the effective therapy for neonatal hypoxic-ischemic brain injury is an important goal. This study was designed to investigate how dexmedetomidine (DEX) contribute to hypoxic brain injury. Methods: Developing Sprague-Dawley rat models of hypoxia/reoxygenation (H/R) injury were constructed to simulate neonatal hypoxic brain injury for DEX treatment. Immunohistochemistry and western blot were performed to measure neuroglobin (Ngb) protein expression in hippocampal tissues. Hippocampal neuron injury and apoptosis were detected by Nissl staining and TUNEL assay, respectively. A Morris water maze (MWM) test was performed to evaluate the long-term learning and memory function. Results: The expression of Ngb was increased following H/R model establishment and up-regulated by medium and high doses of DEX, but not up-regulated by low doses of DEX. Medium and high doses of DEX alleviated the H/R injury as well as induced the reduction of Nissl bodies and apoptosis. Besides, medium and high doses of DEX down-regulated cytosolic Cyt-c, Apaf-1, and caspase-3 in H/R injury model. MWM test showed that medium and high doses of DEX significantly shortened the escape latency and enhanced the number of platform crossings. However, low doses of DEX have no effect on Nissl bodies, mitochondrial apoptosis, expression of apoptosis-related proteins and long-term learning functions. Conclusions: DEX induced Ngb expression in H/R rat models. The neuroprotection of DEX-mediated Ngb up-regulation may be achieved by inhibiting neuronal apoptosis through the mitochondrial pathway. Findings indicated that DEX may be useful as an effective therapy for neonatal hypoxic brain injury. [ABSTRACT FROM AUTHOR]

Including sex is of paramount importance in preclinical and clinical stroke researches, and molecular studies dealing in depth with sex differences in stroke pathophysiology are needed. To gain insight into the molecular sex dimorphism of ischaemic stroke in rat cerebral cortex, male and female adult rats were subjected to transient middle cerebral artery occlusion. The expression of neuroglobin (Ngb) and other functionally related molecules involved in sex steroid signalling (oestrogen and androgen receptors), steroidogenesis (StAR, TSPO and aromatase) and autophagic activity (LC3B‐II/LC3B‐I ratio, UCP2 and HIF‐1α) was assessed in the ipsilateral ischaemic and contralateral non‐ischaemic hemispheres. An increased expression of Ngb was detected in the injured female cerebral cortex. In contrast, increased expression of oestrogen receptor α, GPER, StAR, TSPO and UCP2, and decreased androgen receptor expression were detected in the injured male cortex. In both sexes, the ischaemic insult induced an upregulation of LC3B‐II/‐I ratio, indicative of increased autophagy. Therefore, the cerebral cortex activates both sex‐specific and common molecular responses with neuroprotective potential after ischaemia–reperfusion, which globally results in similar stroke outcome in both sexes. Nonetheless, these different potential molecular targets should be taken into account when neuroprotective drugs aiming to reduce brain damage in ischaemic stroke are investigated. [ABSTRACT FROM AUTHOR]

The iron-containing protein neuroglobin (Ngb) involved in the transport of oxygen is generally considered the precursor of all animal globins. In this report, we studied the structure of Ngb of the cold-water sponge Halisarca dujardinii. In sponges, the oldest multicellular organisms, the Ngb gene contains three introns. In contrast to human Ngb, its promoter contains a TATA-box, rather than CG-rich motifs. In sponges, Ngb consists of 169 amino acids showing rather low similarity with its mammalian orthologues. It lacks Glu and Arg residues in positions required for prevention of hypoxia-related apoptosis. Nevertheless, Ngb contains both proximal and distal conserved heme-biding histidines. The primary structure of H. dujardinii neuroglobin predicted by sequencing was confirmed by mass-spectrometry analysis of recombinant Ngb expressed in E. coli. The high level of Ngb expression in sponge tissues suggests its possible involvement in the gas metabolism and presumably in other key metabolic processes in H. dujardinii. [ABSTRACT FROM AUTHOR]

Objective. To assess the neuroglobin content of cerebellar Purkinje cells during experimental cholestasis in rats. Materials and methods. Studies were performed on paraffin sections of the cerebellar cortex processed for immunohistochemical detection of neuroglobin in Purkinje neurons in 60 mongrel male rats weighing 200–250 g after experimental treatment. Experimental animals underwent ligation of the common bile duct, while control animals underwent sham operations not preventing physiological bile outflow into the duodenum. Results. After ligation of the common bile duct, the neuroglobin content in the perikarya of cerebellar Purkinje neurons showed wavelike changes: it initially decreased on experimental days 2–20 (with a minimum on days 5–10) in conditions of cholestasis and then increased on days 45–90 of natural recovery from cholestasis (with a maximum on day 45). Conclusions. Ligation of the common bile duct produced wavelike changes in the neuroglobin content in the perikarya of cerebellar Purkinje neurons, with a significant decrease in cholestasis and an increase on spontaneous recovery from cholestasis. [ABSTRACT FROM AUTHOR]

Acute inhalation of combustion smoke produces long-term neurologic deficits in survivors. To study the mechanisms that contribute to the development of neurologic deficits and identify targets for prevention, we developed a mouse model of acute inhalation of combustion smoke, which supports longitudinal investigation of mechanisms that underlie the smoke induced inimical sequelae in the brain. Using a transgenic mouse engineered to overexpress neuroglobin, a neuroprotective oxygen-binding globin protein, we previously demonstrated that elevated neuroglobin preserves mitochondrial respiration and attenuates formation of oxidative DNA damage in the mouse brain after smoke exposure. In the current study, we show that elevated neuronal neuroglobin attenuates the persistent inflammatory changes induced by smoke exposure in the mouse brain and mitigates concordant smoke-induced long-term neurobehavioral deficits. Specifically, we found that increases in hippocampal density of GFAP and Iba-1 positive cells that are detected post-smoke in wild-type mice are absent in the neuroglobin overexpressing transgenic (Ngb-tg) mice. Similarly, the smoke induced hippocampal myelin depletion is not observed in the Ngb-tg mice. Importantly, elevated neuroglobin alleviates behavioral and memory deficits that develop after acute smoke inhalation in the wild-type mice. Taken together, our findings suggest that the protective effects exerted by neuroglobin in the brains of smoke exposed mice afford protection from long-term neurologic sequelae of acute inhalation of combustion smoke. Our transgenic mouse provides a tool for assessing the potential of elevated neuroglobin as possible strategy for management of smoke inhalation injury. [ABSTRACT FROM AUTHOR]

Astrocytes are specialized cells capable of regulating inflammatory responses in neurodegenerative diseases or traumatic brain injury. In addition to playing an important role in neuroinflammation, these cells regulate essential functions for the preservation of brain tissue. Therefore, the search for therapeutic alternatives to preserve these cells and maintain their functions contributes in some way to counteract the progress of the injury and maintain neuronal survival in various brain pathologies. Among these strategies, the conditioned medium from human adipose-derived mesenchymal stem cells (CM-hMSCA) has been reported with a potential beneficial effect against several neuropathologies. In this study, we evaluated the potential effect of CM-hMSCA in a model of human astrocytes (T98G cells) subjected to scratch injury. Our findings demonstrated that CM-hMSCA regulates the cytokines IL-2, IL-6, IL-8, IL-10, GM-CSF, and TNF-α, downregulates calcium at the cytoplasmic level, and regulates mitochondrial dynamics and the respiratory chain. These actions are accompanied by modulation of the expression of different proteins involved in signaling pathways such as AKT/pAKT and ERK1/2/pERK, and may mediate the localization of neuroglobin (Ngb) at the cellular level. We also confirmed that Ngb mediated the protective effects of CM-hMSCA through regulation of proteins involved in survival pathways and oxidative stress. In conclusion, regulation of brain inflammation combined with the recovery of fundamental cellular aspects in the face of injury makes CM-hMSCA a promising candidate for the protection of astrocytes in brain pathologies. [ABSTRACT FROM AUTHOR]

As limits on O2 availability during submergence impose severe constraints on aerobic respiration, the oxygen binding globin proteins of marine mammals are expected to have evolved under strong evolutionary pressures during their land-to-sea transition. Here, we address this question for the order Sirenia by retrieving, annotating, and performing detailed selection analyses on the globin repertoire of the extinct Steller's sea cow (Hydrodamalis gigas), dugong (Dugong dugon), and Florida manatee (Trichechus manatus latirostris) in relation to their closest living terrestrial relatives (elephants and hyraxes). These analyses indicate most loci experienced elevated nucleotide substitution rates during their transition to a fully aquatic lifestyle. While most of these genes evolved under neutrality or strong purifying selection, the rate of nonsynonymous/synonymous replacements increased in two genes (Hbz-T1 and Hba-T1) that encode the α-type chains of hemoglobin (Hb) during each stage of life. Notably, the relaxed evolution of Hba-T1 is temporally coupled with the emergence of a chimeric pseudogene (Hba-T2/Hbq-ps) that contributed to the tandemly linked Hba-T1 of stem sirenians via interparalog gene conversion. Functional tests on recombinant Hb proteins from extant and ancestral sirenians further revealed that the molecular remodeling of Hba-T1 coincided with increased Hb–O2 affinity in early sirenians. Available evidence suggests that this trait evolved to maximize O2 extraction from finite lung stores and suppress tissue O2 offloading, thereby facilitating the low metabolic intensities of extant sirenians. In contrast, the derived reduction in Hb–O2 affinity in (sub)Arctic Steller's sea cows is consistent with fueling increased thermogenesis by these once colossal marine herbivores. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are clusters of silver atoms with diameters that range from 1 to 100 nm. Due to the various shapes and large surface areas, AgNPs have been employed in the food and textile industries and medical fields. Therefore, because of the widespread use of these compounds, the aim of this study was to evaluate the effect of AgNP exposure on the gene and protein expression levels of Neuroglobin (Ngb) and Cytoglobin (Cygb), in the rat cortex, hippocampus and cerebellum. Post-natal day (PND) 21 male Wistar rats were randomly divided into three groups. One group received 15 μg/kg body weight of AgNP by gavage another group received 30 μg/kg and the control group that received saline, from PND23 to PND58. On PND102 the animals were euthanized and the cortex, hippocampus and cerebellum were isolated and evaluated for gene and protein expression levels of Nbg and Cygb. The results demonstrated that the 30 μg/kg AgNP group displayed increased gene and protein expression of Cygb in the cortex. In the Hippocampus, AgNP exposure did not modulate gene or protein expression levels of Ngb and Cygb. In cerebellum the Ngb gene and protein expression was increased with both doses of AgNP. AgNP exposure during prepubescence can modulate the gene and protein expression levels of Ngb and Cygb in adulthood. Furthermore, the observed modulation was specific to the cerebellum, and cortex, and was dose dependent. [ABSTRACT FROM AUTHOR]

Background: Many studies have reported that sevoflurane can increase neuronal apoptosis and result in cognitive deficits in rodents. Although neurotoxicity may be associated with mitochondrial dysfunction and oxidative stress, the exact mechanism remains unclear. In order to evaluate potential treatment therapies, we studied the effects of hemin on neurotoxicity of neonatal rat sevoflurane exposure. Methods: Postnatal day (P) seven rats were assigned randomly to four groups; (1) group C: non-anesthesia, (2) group H: intraperitoneal hemin (50 mg kg−1) treatment on days 5 and 6, (3) group S: 3% sevoflurane exposure for 4 h, and (4) group SH: hemin treatment + sevoflurane exposure. The expression of neuroglobin in neonatal hippocampus was determined by western blot and immunohistochemistry. Neuroglobin was localized by immunofluorescence. Western blot for the expression of cleaved caspase-3 and TUNEL were used to detect neonatal hippocampal apoptosis, and cytochrome c was used to evaluate mitochondrial function. Drp-1 and Mfn-2 immunoblotting were used to assess mitochondrial dynamics. The Morris water maze test was performed to detect cognitive function in the rats on P30. Results: Exposure to sevoflurane increased the expression of cleaved caspase-3, cytochrome c , and Drp1 in the neonatal hippocampus and resulted in cognitive deficiency but decreased expression of Mfn2. Hemin reduced apoptosis, improved mitochondrial dynamics and ameliorated the cognitive impairment caused by sevoflurane exposure. Conclusion: Hemin reduced neuronal apoptosis, improved mitochondrial dynamics and protected against cognitive deficits induced by sevoflurane in neonatal rats. This neuroprotective effect may be achieved by increasing the expression of neuroglobin. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases, such as Parkinson and Alzheimer, are among the main public health issues in the world due to their effects on life quality and high mortality rates. Although neuronal death is the main cause of disruption in the central nervous system (CNS) elicited by these pathologies, other cells such as astrocytes are also affected. There is no treatment for preventing the cellular death during neurodegenerative processes, and current drug therapy is focused on decreasing the associated motor symptoms. For these reasons, it has been necessary to seek new therapeutical procedures, including the use of growth factors to reduce α-synuclein toxicity and misfolding in order to recover neuronal cells and astrocytes. Additionally, it has been shown that some growth factors are able to reduce the overproduction of reactive oxygen species (ROS), which are associated with neuronal death through activation of antioxidative enzymes such as catalase, superoxide dismutase, glutathione peroxidase, and neuroglobin. In the present review, we discuss the use of growth factors such as PDGF-BB, VEGF, BDNF, and the antioxidative enzyme neuroglobin in the protection of astrocytes and neurons during the development of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Neuroglobin (NGB), an antiapoptotic protein upregulated by 17β‐estradiol (E2), is part of E2/estrogen receptor α (ERα) pathway pointed to preserve cancer cell survival in presence of microenvironmental stressors including chemotherapeutic drugs. Here, the possibility that resveratrol (Res), an anticancer plant polyphenol, could increase the susceptibility of breast cancer cells to paclitaxel (Pacl) by affecting E2/ERα/NGB pathway has been evaluated. In MCF‐7 and T47D (ERα‐positive), but not in MDA‐MB 231 (ERα‐negative) nor in SK‐N‐BE (ERα and ERβ positive), Res decreases NGB levels interfering with E2/ERα‐induced NGB upregulation and with E2‐induced ERα and protein kinase B phosphorylation. Although Res treatment does not reduce cell viability by itself, this compound potentiates Pacl proapoptotic effects. Notably, the increase of NGB levels by NGB expression vector transfection prevents Pacl or Res/Pacl effects. Taken together, these findings indicate a new Res‐based mechanism that acts on tumor cells impairing the E2/ERα/NGB signaling pathways and increasing cancer cell susceptibility to chemotherapeutic agent. Res treatment does not reduce cancer cell viability by itself Res interferes with estradiol/estrogen receptor α‐induced NGB upregulation in breast cancer cells This new Res‐based mechanism potentiate cancer cell susceptibility to chemotherapeutic agent [ABSTRACT FROM AUTHOR]

Copyright of Tianjin Medical Journal is the property of Tianjin Medical Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Shandong Medical Journal is the property of Shandong Medical Health Newspapers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After its discovery in 2000, the notion grew that neuroglobin, a neuronal specific heme protein, is involved in cytoprotection. To date, neuroglobin levels have been positively correlated with a beneficial outcome in a plethora of neurotoxic insults, e.g., ischemic and traumatic brain injuries and Alzheimer's disease. The first part of this review goes further into these changes of neuroglobin expression upon different neuronal insults as well as the underlying regulation. In the second part, we shed light on the mechanisms by which neuroglobin contributes to neuroprotection, being (i) the scavenging and detoxification of reactive oxygen/nitrogen species, (ii) the augmentation of the threshold for apoptosis initiation, (iii) its contribution to an anti-inflammatory milieu, and (iv) tissue regeneration. We also consider different neuroglobin models to address as yet unanswered questions. Based on the recent findings and progress in the field, we invigorate the avenues of neuroglobin in neurological ailments to increase in the coming years. [ABSTRACT FROM AUTHOR]

Copyright of Shandong Medical Journal is the property of Shandong Medical Health Newspapers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Human neuroglobin (Ngb) is a hexacoordinated globin which binds some small ligands. Its function is still not well-established, even though Ngb seems to be implicated in the protection against neurodegenerative diseases. It has been shown by molecular dynamics and crystallography that ligand binding could occur thanks to a haem sliding mechanism specific to Ngb. In this paper, we studied some regions which could participate in this mechanism. We used UV-visible spectroscopy, CD and NMR to have a look on the protein structure and NMR and stopped-flow to study the ligand binding properties of the proteins. In the haem environment we mutated the distal histidine H64, the alanine A90 which is on the proximal F helix and the phenylalanine F106 which is close to the haem. We showed that both H64V and A90P variants, which affect the haem coordination, seemed to be important to haem and protein secondary structure stabilities whereas F106L mutation did not affect those properties. Then we confirmed that the cyanide binding kinetics were isomer dependent on wild-type Ngb and A90P and F106L variants. H64V Ngb variant had a behavior similar to wild-type Mb or Hb with a loss of the haem kinetic differentiation. Moreover, our results suggested that one haem isomer was more sensitive to A90P and F106L mutations. Those results brought some evidence that the haem sliding mechanism could occur for the cyanide binding and could be haem isomer dependent. The isomer forms may play distinct roles for the potential function of Ngb in vivo. [ABSTRACT FROM AUTHOR]

Copyright of Trakya University Journal of Natural Sciences is the property of Trakya University Journal of Natural Sciences (TUJNS) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High concentrations of palmitic acid in plasma increase both the inflammation associated with obesity and the susceptibility to develop a neurodegenerative event. In the brain, the inflammatory response is mediated by activated microglial cells, which undergo morphological and biochemical changes and can directly affect cell viability. Recent evidence shows that the use of estrogenic compounds can control microglia-induced inflammation with promising results. In this study, we explored the actions of the synthetic steroid tibolone on BV-2 microglia cells stimulated with palmitic acid. Our results demonstrated that tibolone increased cell viability and reduced nuclear fragmentation and the production of reactive oxygen species, as well as preserved mitochondrial membrane potential. These effects were accompanied by reduced nuclear translocation of NF-κB p65, upregulation of neuroglobin, and improved antioxidant defense. Furthermore, estrogen receptor beta (ERβ) inhibition partially dampened tibolone’s protective actions in BV-2 cells stimulated with palmitic acid. In conclusion, tibolone protects BV-2 cells by a mechanism involving ERβ and upregulation of neuroglobin. [ABSTRACT FROM AUTHOR]

Neuroglobin (NGB) is a relatively recent discovered monomeric heme‐protein, which behave in neurons as a sensor of injuring stimuli including oxidative stress, hypoxia, and neurotoxicity. In addition, the anti‐apoptotic activity of overexpressed NGB has been reported both in neurons and in cancer cell lines. We recently demonstrated that, NGB functions as a compensatory protein of the steroid hormone 17β‐estradiol (E2) protecting cancer cells against the apoptotic death induced by oxidative stress. However, the E2‐induced signaling pathways at the root of NGB over‐expression and mitochondrial re‐localization in breast cancer cells is still elusive. By using a kinase screening library, here, we report that: i) There is a strong positive correlation between NGB and ERα expression and activity in breast cancer cells; ii) The E2‐activated phosphatidyl‐inositol 3 kinase (PI3K)/protein kinase B (AKT) and protein kinase C (PKC) pathways are necessary to modulate the NGB protein levels; iii) The E2‐induced persistent activation of AKT drive NGB to mitochondria; iv) Reactive oxygen species (ROS)‐inducing compounds activating rapidly and transiently AKT does not affect the NGB mitochondrial level; and v) High level of NGB into mitochondria are necessary for the pro‐survival and anti‐apoptotic effect of this globin in cancer cells. As a whole, these results underline the E2 triggered pathways in E2‐responsive breast cancer cells that involve NGB as a compensatory protein devoted to cancer cell survival. [ABSTRACT FROM AUTHOR]

Neuroglobin (Ngb) has been reported to be increased in early and moderately advanced Alzheimer's disease (AD) stages but declined in the severe stage. However, its regulatory mechanisms and pathophysiological roles in the disease remain to be defined. In this study, we found that Ngb expression was significantly upregulated by low dose Aβ25-35, the neurotoxic fragment of Aβ1 - 40 and Aβ1 - 42, but was not further increased by a higher dose of Aβ25-35. Mutation analysis and supershift assay demonstrated that transcription factor Nuclear Factor κB (NFκB), κB2 and κB3 sites located in mouse Ngb promoter region were involved in dynamic regulation of Ngb expression in response to different doses of Aβ25-35 stimulation. In addition, we found that suppression of endogenous Ngb expression exacerbated Aβ25-35-induced neuronal cell death and mitochondrial dysfunction. Our results indicate that endogenous Ngb expression may be upregulated by low dose Aβ25-35, which is responsible for protecting against Aβ25-35-mediated neurotoxicity. These experimental findings suggest that upregulation of endogenous Ngb expression might be an effective intervention approach for AD. [ABSTRACT FROM AUTHOR]

Background: Obstructive sleep apnea (OSA) is a highly prevalent disease manifesting as intermittent hypoxia during sleep (IH) and is increasingly recognized as being independently associated with neurobehavioral deficits. These deficits may be due to increased apoptosis in the hippocampus and cerebral cortex, as well as increased oxidative stress and inflammation. It has been reported that neuroglobin (Ngb) is upregulated in response to hypoxia-ischemia insults and exhibits a protective role in ischemia-reperfusion brain injury. We hypothesized that transgenic overexpression of Ngb would attenuate spatial learning deficits in a murine model of OSA. Methods: Wild-type mice and Ngb overexpressing male mice (Ngb-TG) were randomly assigned to either IH or room air (RA) exposures. The effects of IH during the light period on performance in a water maze spatial task were assessed, as well as anxiety and depressive-like behaviors using elevated plus maze (EPM) and forced swim tests. Cortical tissues from all the mice were extracted for biochemical studies for lipid peroxidation. Results: Ngb TG mice exhibited increased Ngb immunoreactivity in brain tissues and IH did not elicit significant changes in Ngb expression in either Ngb-TG mice or WT mice. On a standard place training task in the water maze, Ngb-TG mice displayed preserved spatial learning, and were protected from the reduced spatial learning performances observed in WT mice exposed to IH. Furthermore, anxiety and depression levels were enhanced in WT mice exposed to IH as compared to RA controls, while alterations emerged in Ngb-TG mice exposed to IH. Furthermore, WT mice, but not Ngb-TG mice had significantly elevated levels of malondialdehyde in cortical lysates following IH exposures. Conclusions: In a murine model of OSA, oxidative stress responses and neurocognitive and behavioral impairments induced by IH during sleep are attenuated by the neuroprotective effects of Ngb. [ABSTRACT FROM AUTHOR]

Platelet-derived growth factor, subtype BB (PDGF-BB) is a mitogenic growth factor produced in different cell types such as platelets, fibroblasts, neurons, and astrocytes. Previous reports have shown that different PDGF isoforms exert a neuroprotective effect in neurons and astrocytes against multiple degenerative insults. Previously, we showed that pretreatment with PDGF-BB for 24 h increased cell viability, preserved nuclear morphology and mitochondrial membrane potential following stimulation with rotenone, and reduced free radical production nearly to control conditions. In the present study, we explored the potential mechanisms associated with PDGF-BB protection against oxidative damage. Our results showed that PDGF-BB protected astrocytic cells through multiple responses, including decrease in the expression of cytoskeleton proteins, attenuated free radicals (reactive oxygen species (ROS)) production, preservation of mitochondrial ultrastructure, and improved expression of neuroglobin (Ngb1). In summary, these findings point out that PDGF-BB protects astrocytic cells by a reduction in ROS production and activation of antioxidant mechanisms. [ABSTRACT FROM AUTHOR]