CYP2C8 and CYP2J2 gene variations increase the risk of hypertensive intracerebral hemorrhage.

PURPOSE: Many studies have shown that cytochrome P450 (CYP) gene polymorphisms are usually associated with an increased risk of cardiovascular and cerebrovascular diseases. To explore the association of CYP2C8 and CYP2J2 gene polymorphisms with hypertensive intracerebral hemorrhage (HICH) in the Han Chinese population. METHODS: Forty HICH patients and 40 control subjects were recruited for this study. Two single nucleotide polymorphisms (SNP) (rs1058932, rs2275622) in the CYP2C8 gene and two SNPs (rs2271800, rs1155002) in the CYP2J2 gene were selected for genotyping by direct sequencing. Statistical analysis was applied to examine the effect of genetic variation on HICH. RESULTS: We found that variant alleles of CYP2C8 rs1058932 (A) and rs2275622 (C) were both significantly associated with HICH, especially in females. We also found significant associations of CYP2C8 rs1058932 (A) and rs2275622 (C) variant alleles with poor outcomes in HICH patients, especially in males. CONCLUSIONS: CYP2C8 gene polymorphisms might increase the risk of HICH in the Han Chinese population and might lead to poor outcomes. This finding adds to the body of literature supporting novel therapeutic strategies for HICH.

Diazoxide pretreatment prevents Aß1-42 induced oxidative stress in cholinergic neurons via alleviating NOX2 expression.

The aggregation and accumulation of amyloid-ß (Aß) plays a significant role in the pathogenesis of Alzheimer's disease. Aß is known to increase free radical production in neuronal cells, leading to oxidative stress and cell death. Diazoxide (DZ), a highly selective drug capable of opening mitochondrial ATP-sensitive potassium channels, has neuroprotective effects against neuronal cell death. However, the mechanism through which DZ protects cholinergic neurons against Aß-induced oxidative injury is still unclear. The present study was designed to investigate the effects of DZ pretreatment against Aß1-42 induced oxidative damage and cytotoxicity. Through measures of DZ effects on Aß1-42 induced cellular damage, reactive oxygen species (ROS) and MDA generation and expressions of gp91phox and p47phox in cholinergic neurons, new insights into the neuroprotective mechanisms can be derived. Aß1-42 significantly decreased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide levels and increased ROS and MDA production; all effects were attenuated by pretreatment with DZ or diphenyleneiodonium chloride (a NOX2 inhibitor). Pretreatment with DZ also attenuated the upregulation of NOX2 subunits (gp91phox and p47phox) induced by Aß1-42. Since NOX2 is one of the main sources of free radicals, these results suggest that DZ can counteract Aß1-42 induced oxidative stress and associated cell death by reducing the level of ROS and MDA, in part, by alleviating NOX2 expression.

Protective effect of combination of sulforaphane and riluzole on glutamate-mediated excitotoxicity.

Threohydroxyaspartate (THA) causes glutamate excitotoxicity in motor neurons in organotypic culture of rat spinal cord. Some drugs, including sulforaphane (SF) and riluzole, can protect motor neuron against excitotoxicity. It has been demonstrated that SF is a potent inducer of Phase II enzymes, while riluzole is a classic anti-glutamate agent. The objective of the current study is to investigate whether the combination of SF and riluzole is superior to either one used alone. In our study, the combination of SF with riluzole not only stimulates the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), reduced nicotinamide adenine dinucleotide phosphate (NADPH): quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO-1), but also reduces the extracellular accumulation of glutamate. When used at optimal doses, SF (10 microM) and riluzole (5 microM), either alone or in combination, all exert significant and similar neuroprotection, as measured by the number of motor neuron, medium malondialdehyde (MDA) level and lactate dehydrogenase (LDH) level. When used at low doses, the combination is better than each agent used alone. In conclusion, these results suggest the potential utility of combination use of SF and riluzole for protection of motor neuron against excitotoxicity.

Neuroprotective potential of phase II enzyme inducer diallyl trisulfide.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease, selectively involving the upper and lower motor neurons. Glutamate excitotoxicity and oxidative stress are important mechanisms for the pathogenesis of ALS. Nuclear-factor erythroid 2-related factor 2 (Nrf2) is a master transcriptional regulator of many cytoprotective genes. Nrf2 signal pathway could induce a series of antioxidant enzyme, anti-inflammatory and antitoxic protein. The expression of these antioxidant enzymes and antioxidant proteins in nervous system exhibited broad neuroprotection against injury by glutamate. Diallyl trisulfide (DATS) was previously shown to induce many Nrf2 target genes in non-nervous cells. Our studies have shown that DATS at 50 microM caused activation of Nrf2 and Nrf2 target gene in rat spinal cord explants. DATS also protected motor neurons against glutamate-induced excitotoxicity. These have identified DATS as a promising neuroprotective agent and suggest that the activation of Nrf2 signal pathway may be a new strategy in neurodegeneration disease.

Role and mechanisms of cytokines in the secondary brain injury after intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is a common and severe cerebrovascular disease that has high mortality. Few survivors achieve self-care. Currently, patients receive only symptomatic treatment for ICH and benefit poorly from this regimen. Inflammatory cytokines are important participants in secondary injury after ICH. Increases in proinflammatory cytokines may aggravate the tissue injury, whereas increases in anti-inflammatory cytokines might be protective in the ICH brain. Inflammatory cytokines have been studied as therapeutic targets in a variety of acute and chronic brain diseases; however, studies on ICH are limited. This review summarizes the roles and functions of various pro- and anti-inflammatory cytokines in secondary brain injury after ICH and discusses pathogenic mechanisms and emerging therapeutic strategies and directions for treatment of ICH.

Serum ferritin is a candidate biomarker of disease aggravation in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. The mechanism that defines the loss of neurons in ALS is still not clearly understood, and there is no effective therapy to block its progression. Previous studies indicate that a disorder of iron homeostasis exists in ALS and based on this, the change of serum iron and ferritin and the association between iron metabolism and clinical features in Chinese Han patients with ALS was further investigated in the present study, in order to define its pathogenesis. Two cohorts were established: An ALS group consisting of 24 patients and a control group consisting of 38 healthy volunteers. Venous blood samples were collected for serum iron and ferritin analysis. The results indicated that the levels of serum iron were significantly decreased in patients with ALS (P<0.05), while there was no significant difference in serum ferritin between the ALS and control groups. However, the levels of serum ferritin were increased significantly in ALS patients with bulbar-onset (vs. limb-onset in females), dysphagia (vs. without dysphagia), longer disease duration (>12 months vs. ≤12 months in males) and lower ALS Functional Rating Scale-Revised score (<33 vs. ≥33; P<0.05). These results suggested that there was dysregulation of iron metabolism in Chinese Han patients with ALS and that serum ferritin may be a candidate biomarker of aggravation in these patients.

Effects of epigallocatechin­3­gallate on iron metabolism in spinal cord motor neurons.

Accumulating evidence suggests that iron homeostasis is disordered in amyotrophic lateral sclerosis (ALS). In view of the promising performance of epigallocatechin­3­gallate (EGCG) in neuroprotection studies, the present study aimed to verify whether EGCG protects motor neurons in an ALS model, and whether it has any effects on iron metabolism using an ELISA and western blotting. The results demonstrated that EGCG decreased oxidative stress and protected motor neurons in the organotypic culture of the rat spinal cord. Furthermore, total iron levels increased significantly in the spinal cord following 3 weeks of treatment with threo­hydroxyaspartate. In addition, the expression of influx proteins (transferrin receptor and divalent metal­ion transporter 1) increased significantly. However, EGCG demonstrated no effect on total iron levels and the expression of influx proteins. In conclusion, EGCG leads to a decrease in oxidative stress levels, leading to motor neuron protection in the organotypic culture of a rat spinal cord; however, EGCG does not alter iron metabolism protein expression regulation.

miR-137 regulates the migration of human umbilical vein endothelial cells by targeting ephrin-type A receptor 7.

MicroRNAs (miRNAs) are short non-coding RNAs, which negatively regulate gene expression. Post­transcriptional regulation by miRNAs is important for organism development. In addition, endothelial cells are key regulators of angiogenesis. By using the 3-(4,5-dimethylthiazol-2-yl)­2,5­diphenyltetrazolium bromide (MTT), migration and gelatin sponge-chorioallantoic membrane assays, it was demonstrated that when miR-137 was overexpressed, cell viability and migration decreased. In addition, it was observed that blocking endogenous miR-137 increased cell viability and migration. Bioinformatics analysis indicated that the 3'­untranslated region (3'UTR) of the ephrin type-A receptor 7 (EPHA7) has a putative binding site for miR-137. miR-137 is able to directly bind to the EPHA7 3'UTR and negatively regulate the expression of EPHA7. miR-137 is also able to decrease the growth and migration of human umbilical vein endothelial cells (HUVECs). The identification of the function of miR-137 and its target gene EPHA7 in HUVECs may provide novel insights into the mechanisms of angiogenesis.

Effect of the human SOD1-G93A gene on the Nrf2/ARE signaling pathway in NSC-34 cells.

Dominant mutations in superoxide dismutase 1 (SOD1) are a frequent cause of the lethal neurodegenerative disease amyotrophic lateral sclerosis (ALS). The nuclear factor erythroid 2­related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway is the major cellular defense mechanism against oxidative stress, however, its role in ALS remains to be fully elucidated. Therefore, the present study aimed to investigate whether the human SOD1-G93A gene affected the Nrf2/ARE signaling pathway in an ALS cell model. The soma became round and the number of neurites decreased in the NSC-34 cells transfected with the hSOD1-G93A gene, and the neurites were shorter and oxidative stress was increased compared with the normal NSC-34 cells. Furthermore, the mRNA and protein expression of Nrf2, heme oxygenase-1 and NAD(P)H: quinone oxidoreductase 1 was significantly decreased in the NSC-34 cells transfected with the human SOD1-G93A gene. The present study indicated that human SOD1-G93A damaged the Nrf2/ARE signaling pathway in the ALS cell model and reduced the ability of cells to protect against oxidative injury.

Increased iron level in motor cortex of amyotrophic lateral sclerosis patients: an in vivo MR study.

Amyotrophic lateral sclerosis (ALS) is one of the most common neurodegenerative disorders, but no definite mechanism has been defined on the loss of motor neurons in ALS and currently no therapy can block its progression. Many lines of evidence indicate that there is a disorder of iron homeostasis in ALS, and thus we sought to test the iron level in ALS patients by susceptibility weighted imaging (SWI). Sixteen ALS patients and 16 healthy persons underwent brain scans using SWI with a 3T Siemens MR scanner. The red nucleus, substantia nigra, globus pallidus, putamen, the head of caudate nucleus, and motor cortex were measured in the filtered phase images and analysed for their SWI phase values as relative marker for iron content. We found that phase shift values were significantly higher in the motor cortex of ALS patients by SWI, indicating increased iron level in this area. In contrast, we found that there were no differences of phase shift values between ALS patients and healthy controls in the other nuclei including the red nucleus, substantia nigra, globus pallidus, putamen and the head of the caudate nucleus. Furthermore, we found that there were no relationships between SWI signal and some clinical features of ALS. In conclusion, these results demonstrate that iron level increases in the motor cortex of ALS and that SWI is a reliable method to test iron in the brain.

Epigallocatechin-3-gallate protects motor neurons and regulates glutamate level.

Epigallocatechin-3-gallate (EGCG) is a major component of green tea polyphenols which displays potential properties of anticancer and neuroprotection. Here we show that protection of motor neuron by EGCG is associated with regulating glutamate level in organotypic culture of rat spinal cord. In this model, EGCG blocked glutamate excitotoxicity caused by threohydroxyaspartate, an inhibitor of glutamate transporter. This property of EGCG may be not due to its intrinsic antioxidative activity, because another antioxidant could not regulate glutamate level under the same condition. These results show that EGCG may be a potential therapeutic candidate for neurodegenerative diseases involving glutamate excitotoxicity such as ALS.

Iron is a potential key mediator of glutamate excitotoxicity in spinal cord motor neurons.

Threohydroxyaspartate (THA)-induced glutamate excitotoxicity in organotypic culture of rat spinal cord is a well-known model of motor neuron degeneration. THA causes accumulation of synaptic glutamate and over stimulation of the postsynaptic receptor by inhibiting glutamate uptake. This model has also been used to identify agents that inhibit glutamate excitotoxicity by increasing the expression of glutamate transporter. We now show that THA also increases iron level in rat spinal cord tissue, with concomitant modulation of key iron transport and storage proteins, including transferrin receptor, divalent metal-ion transporter 1 and ferritin. More significantly, iron chelator deferoxamine (DFO) was able to completely prevent THA-induced motor neuron degeneration. The protective effect of DFO did not involve enhancing glutamate uptake. These data provide new mechanistic insight into THA-induced glutamate excitotoxicity and suggest that blocking THA-induced iron rise alone may be sufficient for prevention of glutamate excitotoxicity.