2-Methoxystypandrone ameliorates brain function through preserving BBB integrity and promoting neurogenesis in mice with acute ischemic stroke.

2-Methoxystypandrone (2-MS), a naphthoquinone, has been shown to display an immunomodulatory effect in a cellular model. To explore whether 2-MS could protect mice against cerebral ischemic/reperfusion (I/R)-induced brain injury, we evaluated 2-MS's protective effects on an acute ischemic stroke by inducing a middle cerebral artery occlusion/reperfusion (MCAO) injury in murine model. Treatment of mice that have undergone I/R injury with 2-MS (10-100 μg/kg, i.v.) at 2 h after MCAO enhanced survival rate and ameliorated neurological deficits, brain infarction, neural dysfunction and massive oxidative stress, due to an enormous production of free radicals and breakdown of blood-brain barrier (BBB) by I/R injury; this primarily occurred with extensive infiltration of CD11b-positive inflammatory cells and upexpression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and p65 nuclear factor-kappa B (NF-κB). All of these pathological changes were diminished by 2-MS; 2-MS also intensively limited cortical infarction and promoted upexpression of neurodevelopmental genes near peri-infarct cortex and endogenous neurogenesis near subgranular zone of hippocampal dentate gyrus and the subventricular zone, most possibly by inactivation of GSK3β which in turn upregulating β-catenin, Bcl-2 adam11 and adamts20. We conclude that 2-MS blocks inflammatory responses by impairing NF-κB signaling to limit the inflammation and oxidative stress for preservation of BBB integrity; 2-MS also concomitantly promotes neurodevelopmental protein expression and endogenous neurogenesis through inactivation of GSK3β to enhance β-catenin signaling for upexpression of neuroprotective genes and proteins.

Chern CM ，Wang YH ，Liou KT ，Hou YC ，Chen CC ，Shen YC ... -  《-》

Salvianolic acid A alleviates ischemic brain injury through the inhibition of inflammation and apoptosis and the promotion of neurogenesis in mice.

Salvianolic acid A (SalA), a chemical type of caffeic acid trimer, has drawn great attention for its potent bioactivities against ischemia-induced injury both in vitro and in vivo. In this study, we evaluated SalA's protective effects against acute ischemic stroke by inducing middle cerebral artery occlusion/reperfusion (MCAO) injuries in mice. Treatment of the mice with SalA (50 and 100μg/kg, i.v.) at 2h after MCAO enhanced their survival rate, improved their moving activity, and ameliorated the severity of brain infarction and apoptosis seen in the mice by diminishing pathological changes such as the extensive breakdown of the blood-brain barrier (BBB), nitrosative stress, and the activation of an inflammatory transcriptional factor p65 nuclear factor-kappa B (NF-κB) and a pro-apoptotic kinase p25/Cdk5. SalA also intensively limited cortical infarction and promoted the expression of neurogenesis protein near the peri-infarct cortex and subgranular zone of the hippocampal dentate gyrus by compromising the activation of GSK3β and p25/Cdk5, which in turn upregulated β-catenin, doublecortin (DCX), and Bcl-2, most possibly through the activation of PI3K/Akt signaling via the upregulation of brain-derived neurotrophic factor. We conclude that SalA blocks inflammatory responses by impairing NF-κB signaling, thereby limiting inflammation/nitrosative stress and preserving the integrity of the BBB; SalA also concomitantly promotes neurogenesis-related protein expression by compromising GSK3β/Cdk5 activity to enhance the expression levels of β-catenin/DCX and Bcl-2 for neuroprotection.

Chien MY ，Chuang CH ，Chern CM ，Liou KT ，Liu DZ ，Hou YC ，Shen YC ... -  《-》

Prodigiosin inhibits gp91(phox) and iNOS expression to protect mice against the oxidative/nitrosative brain injury induced by hypoxia-ischemia.

This study aimed to explore the mechanisms by which prodigiosin protects against hypoxia-induced oxidative/nitrosative brain injury induced by middle cerebral artery occlusion/reperfusion (MCAo/r) injury in mice. Hypoxia in vitro was modeled using oxygen-glucose deprivation (OGD) followed by reoxygenation of BV-2 microglial cells. Our results showed that treatment of mice that have undergone MCAo/r injury with prodigiosin (10 and 100μg/kg, i.v.) at 1h after hypoxia ameliorated MCAo/r-induced oxidative/nitrosative stress, brain infarction, and neurological deficits in the mice, and enhanced their survival rate. MCAo/r induced a remarkable production in the mouse brains of reactive oxygen species (ROS) and a significant increase in protein nitrosylation; this primarily resulted from enhanced expression of NADPH oxidase 2 (gp91(phox)), inducible nitric oxide synthase (iNOS), and the infiltration of CD11b leukocytes due to breakdown of blood-brain barrier (BBB) by activation of nuclear factor-kappa B (NF-κB). All these changes were significantly diminished by prodigiosin. In BV-2 cells, OGD induced ROS and nitric oxide production by up-regulating gp91(phox) and iNOS via activation of the NF-κB pathway, and these changes were suppressed by prodigiosin. In conclusion, our results indicate that prodigiosin reduces gp91(phox) and iNOS expression possibly by impairing NF-κB activation. This compromises the activation of microglial and/or inflammatory cells, which then, in turn, mediates prodigiosin's protective effect in the MCAo/r mice.

Chang CC ，Wang YH ，Chern CM ，Liou KT ，Hou YC ，Peng YT ，Shen YC ... -  《-》

Melatonin ameliorates neural function by promoting endogenous neurogenesis through the MT2 melatonin receptor in ischemic-stroke mice.

Melatonin has many protective effects against ischemic stroke, but the underlying neuroprotective mechanisms are not fully understood. Our aim was to explore the relationship between melatonin's neuroprotective effects and activation of the MT2 melatonin receptor in a murine ischemic-stroke model. Male ICR mice were subjected to a transient middle cerebral ischemic/reperfusional injury, and melatonin (5 and 10 mg/kg, ip) was administrated once daily starting 2 h after ischemia. More than 80% of the mice died within 5 days after stroke without treatment. Melatonin treatment significantly improved the survival rates and neural functioning with modestly prolonged life span of the stroke mice by preserving blood-brain barrier (BBB) integrity via a reduction in the enormous amount of stroke-induced free radical production and significant gp91(phox) cell infiltration. These protective effects of melatonin were reversed by pretreatment with MT2 melatonin receptor antagonists (4-phenyl-2-propionamidotetralin (4P-PDOT) and luzindole). Moreover, treatment with melatonin after stroke dramatically enhanced endogenous neurogenesis (doublecortin positive) and cell proliferation (ki67 positive) in the peri-infarct regions. Most ki67-positive cells were nestin-positive and NG2-positive neural stem/progenitor cells that coexpressed two neurodevelopmental proteins (adam11 and adamts20) and the MT2 melatonin receptor. RT-PCR revealed that the gene expression levels of doublecortin, ki67, adamts20, and adam11 are markedly reduced by stroke, but are restored by melatonin treatment; furthermore, pretreatment with 4P-PDOT and luzindole antagonized melatonin's restorative effect. Our results support the hypothesis that melatonin is able to protect mice against stroke by activating MT2 melatonin receptors, which reduces oxidative/inflammatory stress. This results in the preservation of BBB integrity and enhances endogenous neurogenesis by upregulating neurodevelopmental gene/protein expression.

Chern CM ，Liao JF ，Wang YH ，Shen YC ... -  《-》

Hydrogen sulfide protects blood-brain barrier integrity following cerebral ischemia.

By using two structurally unrelated hydrogen sulfide (H2 S) donors 5-(4-methoxyphenyl) -3H-1, 2-dithiole-3-thione (ADT) and sodium hydrosulfide (NaHS), this study investigated if H2 S protected blood-brain barrier (BBB) integrity following middle cerebral artery occlusion (MCAO). ICR mice underwent MCAO and received H2 S donors at 3 h after reperfusion. Infarction, neurological scores, brain edema, Evans blue (EB) extravasation, and tight junction protein expression were examined at 48 h after MCAO. We also investigated if ADT protected BBB integrity by suppressing post-ischemic inflammation-induced Matrix Metalloproteimase-9 (MMP9) and Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). ADT increased blood H2 S concentrations, decreased infarction, and improved neurological deficits. Particularly, ADT reduced EB extravasation, brain edema and preserved expression of tight junction proteins in the ischemic brain. NaHS also increased blood H2 S levels and reduced EB extravasation following MCAO. Moreover, ADT inhibited expression of pro-inflammatory markers induced Nitric Oxide Synthase (iNOS) and IL-1β while enhanced expression of anti-inflammatory markers arginase 1 and IL-10 in the ischemic brain. Accordingly, ADT attenuated ischemia-induced expression and activity of MMP9. Moreover, ADT reduced NOX-4 mRNA expression, NOX activity, and inhibited nuclear translocation of Nuclear Factor Kappa-B (NF-κB) in the ischemic brain. In conclusion, H2 S donors protected BBB integrity following experimental stroke possibly by acting through NF-κB inhibition to suppress neuroinflammation induction of MMP9 and NOX4-derived free radicals. To determine H2 S effects on blood-brain barrier (BBB) disruption following stroke, we used two structurally unrelated H2 S donors ADT and NaHS. Both ADT and NaHS remarkably protected BBB integrity following experimental stroke. The slow-releasing donor ADT also reduced post-ischemic inflammation-induced expression and activity of MMP9 and NOX4 in the ischemic brain possibly by inhibiting NF-κB activation.

Wang Y ，Jia J ，Ao G ，Hu L ，Liu H ，Xiao Y ，Du H ，Alkayed NJ ，Liu CF ，Cheng J ... -  《-》