Overexpression of cytoglobin gene inhibits hypoxic injury to SH-SY5Y neuroblastoma cells

A plasmid for cytoglobin expression, pAcGFP1-C1-cytoglobin, was transfected into SH-SY5Y cells. Cobalt chloride was used to establish a model of hypoxia. Western blotting indicated that cytoglobin was overexpressed and there was low expression of hypoxia-inducible factor-1α in SH-SY5Y cells after transfection. Following cobalt chloride-induced hypoxia, cytoglobin and hypoxia-inducible fac-tor-1α expression gradually increased in SH-SY5Y cells. Flow cytometry showed that with increas-ing duration of hypoxia, the proportion of normal cells significantly diminished in the transfected and non-transfected groups. The proportion of cells in the early stages of apoptosis increased. However, the proportion of apoptotic cells was significantly lower in the transfected group compared with the non-transfected group. These results demonstrate that cytoglobin and hypoxia-inducible factor-1α are strongly up-regulated by hypoxia, and that there is a strong relationship between hy-poxia-inducible factor-1α and cytoglobin during hypoxic injury.     

Stimulation of central A1 adenosine receptors suppresses seizure and neuropathology in a soman nerve agent seizure rat model

The current regimen for treating nerve agent poisoning does not sufficiently suppress the excitotoxic activity that causes severe brain damage, especially in cases where treatment is delayed and nerve agent-induced status epilepticus develops. New therapeutic targets are required to improve survivability and minimize neuropathology after irreversible acetylcholinesterase inactivation. Earlier studies have shown that systemic delivery of adenosine agonists decreases nerve agent lethality; however, the mechanism of protection remains to be understood. The primary aim of this study was to investigate the role of central adenosine receptor (AR) stimulation in neuroprotection by directly injecting (6)-cyclopentyladenosine (CPA), an adenosine agonist specific to the A1 receptor subtype (A1R), into the brain intracerebroventricularly (ICV) in a soman seizure rat model. In addition to general A1R stimulation, we hypothesized that bilateral micro-injection of CPA into the cholinergic basal forebrain (BF) could also suppress excitotoxic activity. The results from these studies demonstrated that centrally administered adenosine agonists are anti-seizure and neuroprotective. CPA-delivered ICV prevented seizure and convulsion in 100% of the animals. Moreover, neuropathological evaluation indicated that adenosine treatments reduced brain damage from severe to minimal. Inhibition of the BF via CPA had varied results. Some animals were protected by treatment; however, others displayed similar pathology to the control. Overall, these data suggest that stimulating central ARs could be an effective target for the next generation countermeasures for nerve agent intoxication.     

A possible therapeutic potential of quercetin through inhibition of μ-calpain in hypoxia induced neuronal injury:a molecular dynamics simulation study

The neuroprotective property of quercetin is well reported against hypoxia and ischemia in past studies.This property of quercetin lies in its antioxidant property with blood-brain barrier permeability and anti-inflammatory capabilities.μ-Calpain,a calcium ion activated intracellular cysteine protease causes serious cellular insult,leading to cell death in various pathological conditions including hypoxia and ischemic stroke.Hence,it may be considered as a potential drug target for the treatment of hypoxia induced neuronal injury.As the inhibitory property of μ-calpain is yet to be explored in details,hence,in the present study,we investigated the interaction of quercetin with μ-calpain through a molecular dynamics simulation study as a tool through clarifying the molecular mechanism of such inhibition and determining the probable sites and modes of quercetin interaction with the μ-calpain catalytic domain.In addition,we also investigated the structure-activity relationship of quercetin with μ-calpain.Affinity binding of quercetin with μ-calpain had a value of –28.73 k J/mol and a Ki value of 35.87 μM that may be a probable reason to lead to altered functioning of μ-calpain.Hence,quercetin was found to be an inhibitor of μ-calpain which might have a possible therapeutic role in hypoxic injury.     

Association between the use of magnesium sulfate as neuroprotector in prematurity and the neonatal hemodynamic effects

Purpose: Cerebral palsy is often associated with prematurity and magnesium sulfate (MgSO₄) has been used as a neuroprotector, with favorable results. However, its mechanism of action has not been fully elucidated. This study aimed to evaluate the association between MgSO₄ at the imminent premature delivery and neonatal hemodynamic effects.

Materials and methods: A cross-sectional study involving 94 newborns (NB) between 24 and 32?weeks at a Brazilian hospital was performed. Bivariate analysis between the use or the non-use of MgSO₄ and hemodynamic characteristics was performed, using the Chi-square test.

Results: NB were evaluated between those who received MgSO₄ (27.7) and those who did not (72.3%). Normal heart rate was verified in 62.8% of NB, normal respiratory rate in 70.2%, and normal temperature in 22.3%. Oxygen saturation higher or equal than 95% was evidenced in 85.1% of NB, normal hemoglucotest in 74.5%, and hemoglobin greater or equal than 16.4?g/dL in 30.9%. Non-invasive ventilation was performed in 48.9% of NB, while 51.1% were submitted to endotracheal ventilation. There was no significance relation detected between the use of MgSO₄ and the hemodynamic characteristics.

Conclusions: MgSO₄ does not appear to influence hemodynamic factors as a cause of the neuroprotection in premature NB.     

Neuroprotective effect of carnosine in the olfactory bulb after vanadium inhalation in a mouse model

Carnosine (β‐alanyl‐L‐histidine) is synthesized in the olfactory system, has antioxidant activity as a scavenger of free radicals and has been reported to have neuroprotective action in diseases which have been attributed to oxidative damage. In neurodegenerative disorders, such as Parkinson's and Alzheimer's diseases, impairment of olfactory function has been described. Vanadium derivatives are environmental pollutants, and its toxicity has been associated with oxidative stress. Vanadium toxicity on the olfactory bulb was reported previously. This study investigates the neuroprotective effect of carnosine on the olfactory bulb in a mice model of vanadium inhalation. Male mice were divided into four groups: vanadium pentoxide (V₂O₅) [0.02 mol/L] inhalation for one hour twice a week; V₂O₅ inhalation plus 1 mg/kg of carnosine administered daily; carnosine only, and the control group that inhaled saline. The olfactory function was evaluated using the odorant test. Animals were sacrificed four weeks after exposure. The olfactory bulbs were dissected and processed using the rapid Golgi method; cytological and ultrastructural analysis was performed and malondialdehyde (MDA) concentrations were measured. The results showed evidence of olfactory dysfunction caused by vanadium exposure and also an increase in MDA levels, loss of dendritic spines and necrotic neuronal death in the granule cells. But, in contrast, vanadium‐exposed mice treated with carnosine showed an increase in dendritic spines and a decrease in neuronal death and in MDA levels when compared with the group exposed to vanadium without carnosine. These results suggest that dendritic spine loss and ultrastructural alterations in the granule cells induced by vanadium are mediated by oxidative stress and that carnosine may modulate the neurotoxic vanadium action, improving the olfactory function.     

Investigational agents for treatment of traumatic brain injury

Introduction: Traumatic brain injury (TBI) is a major cause of death and disability worldwide. To date, there are no pharmacologic agents proven to improve outcomes from TBI because all the Phase III clinical trials in TBI have failed. Thus, there is a compelling need to develop treatments for TBI.

Areas covered: The following article provides an overview of select cell-based and pharmacological therapies under early development for the treatment of TBI. These therapies seek to enhance cognitive and neurological functional recovery through neuroprotective and neurorestorative strategies.

Expert opinion: TBI elicits both complex degenerative and regenerative tissue responses in the brain. TBI can lead to cognitive, behavioral, and motor deficits. Although numerous promising neuroprotective treatment options have emerged from preclinical studies that mainly target the lesion, translation of preclinical effective neuroprotective drugs to clinical trials has proven challenging. Accumulating evidence indicates that the mammalian brain has a significant, albeit limited, capacity for both structural and functional plasticity, as well as regeneration essential for spontaneous functional recovery after injury. A new therapeutic approach is to stimulate neurovascular remodeling by enhancing angiogenesis, neurogenesis, oligodendrogenesis, and axonal sprouting, which in concert, may improve neurological functional recovery after TBI.     

Low Doses of Camptothecin Induced Hormetic and Neuroprotective Effects in PC12 Cells

Hormetic response is an adaptive mechanism for a cell or organism surviving in an unfavorable environment. It has been an intriguing subject of researches covering a broad range of biological and medical disciplines, in which the underlying significance and molecular mechanisms are under intensive investigation. In the present study, we demonstrated that topoisomerase I inhibitor camptothecin (CPT), a potent anticancer agent, induced an obvious hormetic response in rat pheochromocytoma PC12 cells. Camptothecin inhibited PC12 cell growth at relative high doses as generally acknowledged while stimulated the cell growth by as much as 39% at low doses. Moreover, low doses of CPT protected the cells from hydrogen peroxide (H₂O₂)-induced cell death. Phosphoinositide 3-kinase (PI3K)/Akt and nuclear factor-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathways were reported playing pivotal roles in protecting cells from oxidative stress. We observed that these 2 pathways were upregulated by low doses of CPT, as evidenced by increased levels of phosphorylated PI3K, phosphorylated Akt, phosphorylated mammalian target of rapamycin, Nrf2, and HO-1; and abolishment of the growth-promoting and neuroprotective effects of CPT by {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002, a PI3K inhibitor. These results suggest that the hormetic and neuroprotective effects of CPT at low doses on PC12 cells were attributable, at least partially, to upregulated PI3K/Akt and Nrf2/HO-1 pathways.     

Paeoniflorin ameliorates ischemic neuronal damage in vitro via adenosine A1 receptor-mediated transactivation of epidermal growth factor receptor

Aim:

Paeoniflorin from Chinese herb Paeoniae Radix has been shown to ameliorate middle cerebral artery occlusion-induced ischemia in rats. The aim of this study was to investigate the mechanisms underlying the neuroprotective action of PF in cultured rat cortical neurons.

Methods:

Primary cultured cortical neurons of rats were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R) insult. Cell survival was determined using MTT assay. HEK293 cells stably transfected with A₁R (HEK293/A₁R) were used for detailed analysis. Phosphorylation of the signaling proteins was evaluated by Western blot or immunoprecipitation. Receptor interactions were identified using co-immunoprecipitation and immunofluorescence staining.

Results:

Paeoniflorin (10 nmol/L to 1 μmol/L) increased the survival of neurons subjected to OGD/R. Furthermore, paeoniflorin increased the phosphorylation of Akt and ERK1/2 in these neurons. These effects were blocked by PI3K inhibitor wortmannin or MEK inhibitor U0126. Paeoniflorin also increased the phosphorylation of Akt and ERK1/2 in HEK293/A₁R cells. Both A₁R antagonist DPCPX and EGFR inhibitor AG1478 not only blocked paeoniflorin-induced phosphorylation of ERK1/2 and Akt in HEK293/A₁R cells, but also paeoniflorin-increased survival of neurons subjected to OGD/R. In addition, paeoniflorin increased the phosphorylation of Src kinase and activation of MMP-2 in HEK293/A₁R cells. Both Src inhibitor PP2 and MMP-2/MMP-9 inhibitor BiPs not only blocked paeoniflorin-induced phosphorylation of ERK1/2 (and Akt) in HEK293/A₁R cells, but also paeoniflorin-increased survival of neurons subjected to OGD/R.

Conclusion:

Paeoniflorin promotes the survival of cultured cortical neurons by increasing Akt and ERK1/2 phosphorylation via A₁R-mediated transactivation of EGFR.     

Lentiviral vector delivery of parkin prevents dopaminergic degeneration in an alpha-synuclein rat model of Parkinson's disease

Parkinson's disease (PD) is characterized by a progressive loss of midbrain dopamine neurons and the presence of cytoplasmic inclusions called Lewy bodies. Mutations in several genes including alpha-synuclein and parkin have been linked to familial PD. The loss of parkin's E3-ligase activity leads to dopaminergic neuronal degeneration in early-onset autosomal recessive juvenile parkinsonism, suggesting a key role of parkin for dopamine neuron survival. To evaluate the potential neuroprotective role of parkin in the pathogenesis of PD, we tested whether overexpression of wild-type rat parkin could protect against the toxicity of mutated human A30P alpha-synuclein in a rat lentiviral model of PD. Animals overexpressing parkin showed significant reductions in alpha-synuclein-induced neuropathology, including preservation of tyrosine hydroxylase-positive cell bodies in the substantia nigra and sparing of tyrosine hydroxylase-positive nerve terminals in the striatum. The parkin-mediated neuroprotection was associated with an increase in hyperphosphorylated alpha-synuclein inclusions, suggesting a key role for parkin in the genesis of Lewy bodies. These results indicate that parkin gene therapy may represent a promising candidate treatment for PD.