Hemolysate-induced expression of intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 expression in cultured brain microvascular endothelial cells via through ROS-dependent NF-kappaB pathways

Triterpenes and Aromatic Meroterpenoids with Antioxidant Activity and Neuroprotective Effects from Ganoderma lucidum

Reactive oxygen/nitrogen species generated in the human body can cause oxidative damage associated with many degenerative diseases such as atherosclerosis, dementia, coronary heart diseases, aging, and cancer. There is a great interest in developing new antioxidants from Ganoderma fungus due to its low toxicity. As part of our ongoing search for antioxidative constituents from the fruiting bodies of Ganoderma lucidum, the chemical constituents were investigated and seven secondary metabolites, including one new lanostane triterpene (1), two known aromatic meroterpenoids (6–7), and four known triterpenes (2–5), were isolated by a series of chromatographic methods. The structures of the seven compounds were elucidated by spectroscopic techniques. The isolated compounds were tested in vitro for antioxidant potencies and neuroprotective activities against H₂O₂ and aged Aβ-induced cell death in SH-SY5Y cells. As a result, compounds 1, 6, and 7 exhibited potent antioxidant and neuroprotective activities. Additionally, all isolated compounds were tested for radical scavenging activities. Compounds 6 and 7 showed the comparable free radical scavenging activities with the standard drug in both ABTS (2, 2’-azobis (3-ethylbenzothiazole-6-sulfonaic acid)) and ORAC (oxygen radical absorbance capacity) experiments. The results from this study suggested that G. lucidum and its metabolites (especially the meroterpenoids) may be potential functional food ingredients for the antioxidation and prevention of neurogenerative diseases.

The development of 1,3-diphenylisobenzofuran as a highly selective probe for the detection and quantitative determination of hydrogen peroxide

1,3-Diphenylisobenzofuran (DPBF) has been developed as a selective probe for the detection and quantitative determination of hydrogen peroxide in samples containing different reactive nitrogen and oxygen species (RNOS). DPBF is a fluorescent probe which, for almost 20 years, was believed to react in a highly specific manner toward some reactive oxygen species (ROS) such as singlet oxygen and hydroxy, alkyloxy or alkylperoxy radicals. Under the action of these individuals DPBF has been rapidly transformed to 1,2-dibenzoylbenzene (DBB). In order to check if DPBF can act as a unique indicator of the total amount of different RNOS, as well as oxidative stress caused by an overproduction of these individuals, a series of experiments was carried out, in which DPBF reacted with peroxynitrite anion, superoxide anion, hydrogen peroxide, hypochlorite anion, and anions commonly present under biological conditions, namely nitrite and nitrate. In all cases, except for hydrogen peroxide, the product of the reaction is DBB. Only under the action of H₂O₂ 9-hydroxyanthracen-10(9H)-one (oxanthrone) is formed. This product has been identified with the use of fluorescence spectroscopy, NMR spectroscopy, high performance liquid chromatography coupled with mass spectrometry, infrared spectroscopy, elemental analysis, and cyclic voltammetry (CV). A linear relationship was found between a decrease in the fluorescence intensity of DPBF and the concentration of hydrogen peroxide in the range of concentrations of 0.196-3.941 mM. DPBF responds to hydrogen peroxide in a very specific way with the limits of detection and quantitation of 88 and 122.8 μM, respectively. The kinetics of the reaction between DBBF and H₂O₂ was also studied.

Anti-inflammatory effects of fimasartan via Akt, ERK, and NFκB pathways on astrocytes stimulated by hemolysate

OBJECTIVE

The aim of this study was to investigate whether fimasartan, a novel angiotensin II receptor blocker, modulates hemolysate-induced inflammation in astrocytes.

METHODS

We stimulated astrocytes with hemolysate to induce hemorrhagic inflammation in vitro. Astrocytes were pretreated with fimasartan and then incubated with hemolysate at different durations. Anti-inflammatory cell signaling molecules including Akt, extracellular signal regulated kinase (ERK), NFκB and cyclooxygenase-2 (COX-2) were assessed by western blotting. Pro-inflammatory mediators were evaluated by real-time RT-PCR and ELISA.

RESULTS

The stimulation by hemolysate generated a robust activation of inflammatory signaling pathways in astrocytes. Hemolysate increased the phosphorylation of Akt at 1 h, and ERK1/2 at 20 min compared with the control group and promoted the degradation of IκBα. Pretreated fimasartan significantly decreased hemolysate-induced phosphorylation of Akt and ERK1/2. In addition, fimasartan also suppressed NFκB-related inflammatory pathways induced by hemolysate, including reduction of the gene expression of NFκB, and decreased nuclear translocation of NFκB and degradation of IκB. This reduction of inflammatory upstream pathways decreased the expression of inflammatory end-products: COX-2 and interleukin-1 (IL-1β). Furthermore, the expression of COX-2 was attenuated by both Akt inhibitor (LY294002) and ERK inhibitor (U0126), and IκBα degradation was suppressed by LY294002.

CONCLUSIONS

These results demonstrate that pretreatment with fimasartan to astrocytes suppresses the inflammatory responses induced by hemolysate. Akt, ERK and NFκB were associated with hemolysate-induced COX-2 and IL-1β expression. Based on these mechanisms, fimasartan could be a candidate anti-inflammatory regulator for the treatment of intracerebral hemorrhage.

Blood-brain barrier dysfunction developed during normal aging is associated with inflammation and loss of tight junctions but not with leukocyte recruitment

Background

Functional loss of blood–brain barrier (BBB) is suggested to be pivotal to pathogenesis and pathology of vascular-based neurodegenerative disorders such as Alzheimer’s disease. We recently reported in wild-type mice maintained on standard diets, progressive deterioration of capillary function with aging concomitant with heightened neuroinflammation. However, the mice used in this study were relatively young (12 months of age) and potential mechanisms for loss of capillary integrity were not investigated per se. The current study therefore extended the previous finding to investigate the effect of aging on BBB integrity in aged mice at 24 months and its potential underlying molecular mechanisms.

Results

Immunomicroscopy analyses confirmed significantly increased capillary permeability with heightened neuroinflammation in naturally aged 24-month old mice compared to young control at 3 months of age. Aged mice showed significant attenuation in the expression of BBB tight junction proteins, occludin-1 and to lesser extent ZO-1 compared to young mice. In addition, TNF-α in cerebral endothelial cells of aged mice was significantly elevated compared to controls and this was associated with heightened peripheral inflammation. The expression of ICAM-1 and VCAM-1 remained unelevated, and no sign of leukocyte recruitment was observed in aged mice.

Conclusion

The BBB breakdown that occurs during ordinary aging is associated with inflammation and disruption of tight junction complex assembly but not through leukocyte trafficking.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-015-0029-9) contains supplementary material, which is available to authorized users.

Protective effect of paeoniflorin on Aβ25-35-induced SH-SY5Y cell injury by preventing mitochondrial dysfunction

Alzheimer's disease (AD) is a major neurodegenerative brain disorder affecting about 14 million people worldwide. Aβ-induced cell injury is a crucial cause of neuronal loss in AD, thus the suppression of which might be useful for the treatment of this disease. In this study, we aimed to evaluate the effect of paeoniflorin (PF), a monoterpene glycoside isolated from aqueous extract of Radix Paeoniae Alba, on Aβ25-35-induced cytotoxicity in SH-SY5Y cells. The results showed PF could attenuate or restore the viability loss, apoptotic increase, and ROS production induced by Aβ25-35 in SH-SY5Y cells. In addition, PF strikingly inhibited Aβ25-35-induced mitochondrial dysfunction, which includes decreased mitochondrial membrane potential, increased Bax/Bcl-2 ratio, cytochrome c release and activity of caspase-3 and caspase-9. Therefore, our study provided the first experimental evidence that PF could modulate ROS production and apoptotic mitochondrial pathway in model of neuron injury in vitro and which might provide new insights into its application toward Alzheimer's disease therapy.

Methemoglobin-induced signaling and chemokine responses in human alveolar epithelial cells

Diffuse alveolar hemorrhage is characterized by the presence of red blood cells and free hemoglobin in the alveoli and complicates a number of serious medical and surgical lung conditions including the pulmonary vasculitides and acute respiratory distress syndrome. In this study we investigated the hypothesis that exposure of human alveolar epithelial cells to hemoglobin and its breakdown products regulates chemokine release via iron- and oxidant-mediated activation of the transcription factor NF-κB. Methemoglobin alone stimulated the release of IL-8 and MCP-1 from A549 cells via activation of the NF-κB pathway; additionally, IL-8 required ERK activation and MCP-1 required JNK activation. Neither antioxidants nor iron chelators and knockdown of ferritin heavy and light chains affected these responses, indicating that iron and reactive oxygen species are not involved in the response of alveolar epithelial cells to methemoglobin. Incubation of primary cultures of human alveolar type 2 cells with methemoglobin resulted in a similar pattern of chemokine release and signaling pathway activation. In summary, we have shown for the first time that methemoglobin induced chemokine release from human lung epithelial cells independent of iron- and redox-mediated signaling involving the activation of the NF-κB and MAPK pathways. Decompartmentalization of hemoglobin may be a significant proinflammatory stimulus in a variety of lung diseases.

Protective effects of paeoniflorin against glutamate-induced neurotoxicity in PC12 cells via antioxidant mechanisms and Ca(2+) antagonism

Preclinical and clinical investigations have shown hippocampal neuronal atrophy and destruction were observed in patients with depression, which could be ameliorated by the treatment with antidepressants. Therefore, neuroprotection has been proposed to be one of the acting mechanisms of antidepressant. Paeoniflorin, a monoterpene glycoside, has been reported to display antidepressant-like effects in animal models of behavioral despair. The present study aimed to examine the protective effect of paeoniflorin on glutamate-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. The results showed that pretreatment with paeoniflorin elevated cell viability, inhibited apoptosis, decreased levels of intracellular reactive oxygen species and malondialdehyde, and enhanced activity of superoxide dismutase in glutamate-treated PC12 cells. Pretreatment with paeoniflorin also reversed the increased intracellular Ca(2+) concentration and the reduced Calbindin-D28K mRNA level caused by glutamate in PC12 cells. The results suggest that paeoniflorin exerts a neuroprotective effect on glutamate-induced neurotoxicity in PC12 cells, at least in part, via inhibiting oxidative stress and Ca(2+) overload. This neuroprotective effect may be one of the action pathways accounting for the in vivo antidepressant activity of paeoniflorin.