Differential regulation of proliferation and differentiation in neural precursor cells by the Jak pathway.

Neuronal precursor cells (NPCs) are temporally regulated and have the ability to proliferate and differentiate into mature neurons, oligodendrocytes, and astrocytes in the presence of growth factors (GFs). In the present study, the role of the Jak pathway in brain development was investigated in NPCs derived from neurosphere cultures using Jak2 and Jak3 small interfering RNAs and specific inhibitors. Jak2 inhibition profoundly decreased NPC proliferation, preventing further differentiation into neurons and glial cells.

Gadd45beta is a novel mediator of cardiomyocyte apoptosis induced by ischaemia/hypoxia.

Aims: Because apoptotic death plays a critical role in cardiomyocyte loss during ischaemic heart injury, a detailed understanding of the mechanisms involved is likely to have a substantial impact on the optimization and development of treatment strategies. The goal of this study was to assess gene profiling during ischaemia/hypoxia and to evaluate the functions of ischaemia/hypoxia-responsive genes in in vivo and in vitro ischaemia/hypoxia-induced cardiomyocyte apoptosis models.

Methods And Results: DNA microarray analysis and real-time polymerase chain reaction were performed on hearts obtained from an in vivo rat transient ischaemia model and on neonatal rat cardiomyocytes from an in vitro hypoxia model.

Role of PKCbetaII and PKCdelta in blood-brain barrier permeability during aglycemic hypoxia.

Blood-brain barrier (BBB) dysfunction contributes to the pathophysiology of cerebrovascular diseases such as stroke. In the present study, we investigated the role of PKC isoforms in aglycemic hypoxia-induced hyperpermeability using an in vitro model of the BBB consisting of mouse bEnd.3 cells.

Cadmium stimulates the expression of vascular cell adhesion molecule-1 (VCAM-1) via p38 mitogen-activated protein kinase (MAPK) and JNK activation in cerebrovascular endothelial cells.

In this study, we examined the effect of Cd on the expression of vascular cell adhesion molecule-1 (VCAM-1) and its mechanisms in bEnd.3 cells. The treatment with Cd increased protein and mRNA expressions of VCAM-1 and increased the phosphorylations of p38, JNK, and ERK.

Calpain-mediated N-cadherin proteolytic processing in brain injury.

Neural-cadherin (N-cadherin), a member of the classical cadherin family of transmembrane glycoproteins, mediates cellular recognition and cell-cell adhesion through calcium-dependent homophilic interactions and plays important roles in the development and maintenance of the nervous system. Metalloproteinase is known to cleave N-cadherin, which is further cleaved by gamma-secretase. The intracellular domain of N-cadherin interacts with beta-catenin, and beta-catenin stability is critical for cell-cell adhesion and cell survival.

Methanolic extract of onion (Allium cepa) attenuates ischemia/hypoxia-induced apoptosis in cardiomyocytes via antioxidant effect.

Background: Although there is growing awareness of the beneficial potential of onion intake to lower the risk of cardiovascular disease, there is little information about the effect of onion on ischemic heart injury, one of the most common cardiovascular diseases.

Aim Of The Study: This study investigates the effect of the methanol-soluble extract of onion on ischemic injury in heart-derived H9c2 cells in vitro and in rat hearts in vivo. The underlying mechanism is also investigated.

Effects of KR-33028, a novel Na+/H+ exchanger-1 inhibitor, on glutamate-induced neuronal cell death and ischemia-induced cerebral infarct.

We investigated the effects of a novel Na(+)/H(+) exchanger-1 (NHE-1) inhibitor KR-33028 on glutamate excitotoxicity in cultured neuron cells in vitro and cerebral infarct in vivo by comparing its potency with that of zoniporide, a well-known, highly potent NHE-1 inhibitor. KR-33028 inhibited NHE-1 activation in a concentration-dependent manner (IC(50)=2.2 nM), with 18-fold greater potency than that of zoniporide (IC(50)=40.

Involvement of endogenous prostaglandin F2alpha on kainic acid-induced seizure activity through FP receptor: the mechanism of proconvulsant effects of COX-2 inhibitors.

COX-2 and prostaglandins (PGs) might play important roles in epilepsy. In kainic acid-induced seizures, the brain largely increases PGD(2), first from COX-1 and later COX-2-induced PGF(2alpha). Pre-treatment with COX-2 inhibitors such as indomethacin, nimesulide, and celecoxib is known to aggravate kainic acid (KA)-induced seizure activity.

Cadmium induces apoptotic cell death through p38 MAPK in brain microvessel endothelial cells.

Cadmium (Cd), an ubiquitous heavy metal, is known to be accumulated outside of the blood-brain barrier. In this study, we investigated whether Cd has cytotoxicity in mouse brain microvascular endothelial cells (bEnd.3).

Anti-hypertensive effect of the Dongchunghacho, Isaria sinclairii, in the spontaneously hypertensive rats.

The present study examined the effect of the methanol extract of Isaria sinclairii, a kind of Donchunghacho (Tochukaso), on blood pressure in spontaneously hypertensive rats (SHR). Blood pressure and heart rate were measured after treatment with the methanol extract of I. sinclairii by the indirect tail-cuff method and the direct in vivo model.

COX-2 is associated with cadmium-induced ICAM-1 expression in cerebrovascular endothelial cells.

In order to get insight into the mechanism of cadmium (Cd)-induced brain injury, we investigated the effects of Cd on the induction of COX-2 and ICAM-1 in bEnd.3 mouse brain endothelial cells (EC). Cd stimulated PGE(2) release in a time and dose dependent manner, which was accompanied by increase of COX-2 expression.

Protective effect of KR-31378 on oxidative stress in cardiac myocytes.

In this study, we investigated whether a novel anti-ischemic KATP opener KR-31378 [(2S,3S,4R)-N"-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methly-2-dimethoxymethly-2H-benzopyran-4-yl)-N'-benzylguanidine] has protective effect against oxidative stress-induced death in heart-derived H9c2 cells. Cell death was induced by BSO, butionine sulfoximine, which inhibits GSH synthesis and subsequently increases reactive oxygen species (ROS) level. Cell death was quantitatively determined by measuring lactate dehydrogenase (LDH) activity and stained by Hoechst 33258.

KR-32570, a novel Na+/H+ exchanger-1 inhibitor, attenuates hypoxia-induced cell death through inhibition of intracellular Ca2+ overload and mitochondrial death pathway in H9c2 cells.

A novel Na+/H+ exchanger-1 (NHE-1) inhibitor [5-(2-methoxy-5-chloro-5-phenyl)furan-2-ylcarbonyl]guanidine (KR-32570) has been previously demonstrated to elicit cardioprotective effect against ischemic injury in rat heart. In the present study, we examined the effects of KR-32570 on cell death induced by hypoxic insult in heart-derived H9c2 cells. Treatment with KR-32570 (1-10 microM) significantly reduced hypoxia-induced necrotic cell death (lactate dehydrogenase release) and apoptotic cell death (TUNEL-positivity, caspase-3 activity).

Effects of sabiporide, a specific Na+/H+ exchanger inhibitor, on neuronal cell death and brain ischemia.

We investigated the effects of an Na(+)/H(+) exchanger inhibitor, sabiporide, on excitotoxicity in cultured neuronal cells and in vivo. Sabiporide attenuated glutamate- or NMDA (N-methyl-d-aspartic acid)-induced neuronal cell death. Sabiporide also reduced glutamate or NMDA-induced increase in [Ca(2+)](i).

Effects of DK-002, a synthesized (6aS,cis)-9,10-Dimethoxy-7,11b-dihydro-indeno[2,1-c]chromene-3,6a-diol, on platelet activity.

In the present study, the mechanism of antiplatelet activity of DK-002, a synthesized (6aS,cis)-9,10-Dimethoxy-7,11b-dihydro-indeno[2,1-c]chromene-3,6a-diol, was investigated. DK-002 inhibited the thrombin, collagen, and ADP-induced rat platelet aggregation in a concentration-dependent manner, with IC50 values of 120, 27, and 47 microM, respectively. DK-002 also inhibited thrombin-induced dense granule secretion, thromboxane A2 synthesis, and [Ca2+]i elevation in platelets.

Arachidonic acid induces neuronal death through lipoxygenase and cytochrome P450 rather than cyclooxygenase.

Arachidonic acid (AA) is released from membrane phospholipids during normal and pathologic processes such as neurodegeneration. AA is metabolized via lipoxygenase (LOX)-, cyclooxygenase (COX)-, and cytochrome P450 (CYP450)-catalyzed pathways. We investigated the relative contributions of these pathways in AA-induced neuronal death.

Activation of protein kinase C-delta attenuates kainate-induced cell death of cortical neurons.

We investigated the role of individual protein kinase C (PKC) isoforms during kainate toxicity in cortical neurons. Treatment with 50 microM kainate induced isoform-specific activation of PKC-delta according to the translocation from the soluble to the particulate fraction, while it caused remarkable decreases in PKC alpha, beta, epsilon and zeta in both fractions. Kainate-induced neuronal death was significantly increased by pharmacological inhibition of PKC-delta with rottlerin, suggesting a protective role of PKC-delta against kainate toxicity.

Antiplatelet activity of BRX-018, (6aS,cis)-malonic acid 3-acetoxy-6a9-bis-(2-methoxycarbonyl-acetoxy)-6,6a,7,11b-tetrahydro-indeno[2,1-c]chromen-10-yl ester methylester.

Brazilin (7,11b-dihydrobenz[b]indeno[1,2-d]pyran-3,6a,9,10 (6H)-tetrol), the major component of Caesalpinia sappan L., was reported to show antiplatelet activity through the inhibition of phospholipase A2 (PLA2) activity and the increase in intracellular free Ca2+ concentration ([Ca2+]i). To search more potential antiplatelet agent, brazilin derivatives were synthesized and examined for their effects on the platelet aggregation.

Role of PKC-delta during hypoxia in heart-derived H9c2 cells.

In the present study, we investigated the role of protein kinase C (PKC) isoforms during hypoxia in heart-derived H9c2 cells. Hypoxia caused a rapid translocation of PKC-delta from soluble to particulate fraction and a downregulation of PKC-epsilon and PKC-zeta, whereas PKC-alpha and PKC-beta I remained unaltered. When H9c2 cells were pretreated with PKC-delta inhibitor rottlerin (3 microM), hypoxia-induced apoptotic and necrotic cell death were significantly increased.

KR-31378, a novel benzopyran analog, attenuates hypoxia-induced cell death via mitochondrial KATP channel and protein kinase C-epsilon in heart-derived H9c2 cells.

A novel compound KR-31378 [(2S,3S,4R)-N''-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methly-2-dimethoxy-methly-2H-benzo-pyran-4-yl)-N-benzylguanidine] has been demonstrated as an anti-ischemic agent in rat heart and brain. Here, we report the effects of this compound on hypoxia-induced cell death and possible signaling pathways in heart-derived H9c2 cells. Treatment with KR-31378 (3-30 microM) 1 h before and during hypoxia significantly reduced hypoxia-induced cell death in a concentration-dependent manner.

Neuroprotection by fructose-1,6-bisphosphate involves ROS alterations via p38 MAPK/ERK.

Fructose-1,6-bisphosphate (FBP) is a glucose metabolism intermediate that shows a neuroprotective action in animal models of ischemia and other injuries. The intracellular mechanism of FBP on neuroprotection has not been previously defined. Here, we examined whether FBP has a neuroprotective effect against excitotoxicity, and whether it affects the production of reactive oxygen species (ROS), which are involved in the MAPK pathway in cortical neurons.

Cadmium stimulates the expression of ICAM-1 via NF-kappaB activation in cerebrovascular endothelial cells.

Cadmium (Cd), a ubiquitous heavy metal, has been shown to accumulate in the central nervous system, especially outside of the blood-brain barrier (BBB), suggesting a potential toxicity to nervous tissue. Thus, we investigated the effect of Cd on intercellular adhesion molecule-1 (ICAM-1) expression, as an indicator of BBB injury, in mouse brain microvessel endothelial cells (bEnd.3 cells).

Role for PKC-epsilon in neuronal death induced by oxidative stress.

We investigated which isoforms of PKCs can be modulated and what their roles are during l-buthionine-S,R-sulfoximine (BSO)-induced neuronal death. We observed the isoform specific translocation of PKC-epsilon from the soluble fraction to the particulate in cortical neurons treated with 10 mM BSO. The translocation of PKC-epsilon by BSO was blocked by antioxidant trolox, suggesting the PKC-epsilon as a downstream of reactive oxygen species (ROS) elevated by BSO.

High-glucose induced protective effect against hypoxic injury is associated with maintenance of mitochondrial membrane potential.

Our previous report has showed that the treatment of 48 h with 22 mM glucose prevents hypoxia-induced cardiac cell death. In the present study, we investigated whether high glucose affects the mitochondrial death pathway during hypoxia, and if it does, what relates to the high glucose induced cardioprotection. Heart-derived H9c2 cells were incubated in low (5.

N-nitrosocarbofuran induces apoptosis in mouse brain microvascular endothelial cells (bEnd.3).

In this study, we investigated whether carbofuran, a commonly used carbamate pesticide, and N-nitrosocarbofuran (NOCF), the N-nitroso metabolite of carbofuran, have cytotoxicity in mouse brain microvascular endothelial cells (bEnd.3). Results from the MTT assay in bEnd.