scholarly journals Hericium erinaceusInhibits TNF-α-Induced Angiogenesis and ROS Generation through Suppression of MMP-9/NF-κB Signaling and Activation of Nrf2-Mediated Antioxidant Genes in Human EA.hy926 Endothelial Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Hebron C. Chang ◽  
Hsin-Ling Yang ◽  
Jih-Hao Pan ◽  
Mallikarjuna Korivi ◽  
Jian-You Pan ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Intercellular Adhesion Molecule ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Dependent Manner ◽  
Antioxidant Genes ◽  
Anti Inflammatory

Hericium erinaceus(HE) is an edible mushroom that has been shown to exhibit anticancer and anti-inflammatory activities. We investigated the antiangiogenic and antioxidant potentials of ethanol extracts of HE in human endothelial (EA.hy926) cells upon tumor necrosis factor-α- (TNF-α-) stimulation (10 ng/mL). The underlying molecular mechanisms behind the pharmacological efficacies were elucidated. We found that noncytotoxic concentrations of HE (50–200 μg/mL) significantly inhibited TNF-α-induced migration/invasion and capillary-like tube formation of endothelial cells. HE treatment suppressed TNF-α-induced activity and/or overexpression of matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1). Furthermore, HE downregulated TNF-α-induced nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) followed by suppression of I-κB (inhibitor-κB) degradation. Data from fluorescence microscopy illustrated that increased intracellular ROS production upon TNF-α-stimulation was remarkably inhibited by HE pretreatment in a dose-dependent manner. Notably, HE triggered antioxidant gene expressions of heme oxygenase-1 (HO-1),γ-glutamylcysteine synthetase (γ-GCLC), and glutathione levels, which may contribute to inhibition of ROS. Increased antioxidant status was associated with upregulated nuclear translocation and transcriptional activation of NF-E2related factor-2 (Nrf2) in HE treated cells. Our findings conclude that antiangiogenic and anti-inflammatory activities ofH. erinaceusmay contribute to its anticancer property through modulation of MMP-9/NF-κB and Nrf2-antioxidant signaling pathways.

scholarly journals Antioxidant and Anti-Inflammatory Effects of Bischofia javanica (Blume) Leaf Methanol Extracts through the Regulation of Nrf2 and TAK1

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1295
Author(s):  
Sewoong Lee ◽  
Jain Ha ◽  
Jiyoung Park ◽  
Eunjeong Kang ◽  
Sung-Hyun Jeon ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
The Philippines ◽  
No Production ◽  
Related Factor ◽  
Nuclear Factor ◽  
Antioxidant Genes ◽  
Methanol Extracts ◽  
Anti Inflammatory ◽  
Bischofia Javanica

Bischofia javanica (Blume) has been traditionally used to treat inflammatory diseases such as tonsillitis and ulcers throughout Asia, including China, Indonesia, and the Philippines: however, the molecular mechanisms by which B. javanica exerts its antioxidant and anti-inflammatory properties remain largely unknown. In this study, we analyzed the antioxidant and anti-inflammatory mechanisms of methanol extracts of B. javanica leaves (MBJ) in vitro and in vivo. MBJ decreased nitric oxide (NO) production and the expression of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, in lipopolysaccharide (LPS)-treated RAW 264.7 cells. The observed suppression of inflammatory responses by MBJ was correlated with an inhibition of the nuclear factor-κB (NF-κB) and the mitogen-activated protein kinase (MAPK) pathways. Additionally, MBJ induced nuclear translocation of the nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that upregulates the expression of anti-inflammatory and antioxidant genes. Furthermore, MBJ exhibited antioxidant and anti-inflammatory effects in an acute hepatitis mouse model. In conclusion, our results confirm the medicinal properties of B. javanica, and therefore MBJ could be applied to improve inflammatory and redox imbalances in different types of pathologies.

scholarly journals Anti-Inflammatory and Antioxidant Effects of Soroseris hirsuta Extract by regulating iNOS/NF-κB and NRF2/HO-1 Pathways in Murine Macrophage RAW 264.7 Cells

2021 ◽  
Vol 11 (10) ◽  
pp. 4711
Author(s):  
Woo Jin Lee ◽  
Wan Yi Li ◽  
Sang Woo Lee ◽  
Sung Keun Jung
Keyword(s):  
Nitric Oxide ◽  
Nuclear Translocation ◽  
Antioxidant Properties ◽  
Raw 264.7 Cells ◽  
Heme Oxygenase 1 ◽  
Raw 264.7 ◽  
Related Factor ◽  
Iκb Kinase ◽  
Anti Inflammatory ◽  
Antioxidant Effects

Until now, the physiological effects of Soroseris hirsuta were primarily unknown. Here we have evaluated the anti-inflammatory and antioxidant effects of Soroseris hirsuta extract (SHE) on lipopolysaccharide (LPS)-activated murine macrophages RAW 264.7 cells. SHE inhibited nitric oxide expression and inducible nitric oxide synthase expression in RAW 264.7 cells treated with LPS. Moreover, SHE suppressed LPS-induced phosphorylation of IκB kinase, inhibitor of kappa B, p65, p38, and c-JUN N-terminal kinase. Western blot and immunofluorescence analyses showed that SHE suppressed p65 nuclear translocation induced by LPS. Furthermore, SHE inhibited the reactive oxygen species in LPS-treated RAW 264.7 cells. SHE significantly increased heme oxygenase-1 expression and the nuclear translocation of nuclear factor erythroid 2-related factor 2. SHE suppressed LPS-induced interleukin-1β mRNA expression in RAW 264.7 cells. Thus, SHE is a promising nutraceutical as it displays anti-inflammatory and antioxidant properties.

scholarly journals Suppression of LPS-Induced Inflammation by Chalcone Flavokawain A through Activation of Nrf2/ARE-Mediated Antioxidant Genes and Inhibition of ROS/NFκB Signaling Pathways in Primary Splenocytes

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Hsin-Ling Yang ◽  
Ting-Yu Yang ◽  
Yugandhar Vudhya Gowrisankar ◽  
Chun-Huei Liao ◽  
Jiunn-Wang Liao ◽  
...  
Keyword(s):  
Proinflammatory Cytokine ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Ex Vivo ◽  
Root Extract ◽  
Piper Methysticum ◽  
Serum Lipase ◽  
Antioxidant Genes ◽  
Anti Inflammatory

Oxidative stress is an important contributing factor for inflammation. Piper methysticum, also known as Kava-kava, is a shrub whose root extract has been consumed as a drink by the pacific islanders for a long time. Flavokawain A (FKA) is a novel chalcone derived from the kava plant that is known to have medicinal properties. This study was aimed at demonstrating the antioxidant molecular mechanisms mediated by FKA on lipopolysaccharide- (LPS-) induced inflammation in BALB/c mouse-derived primary splenocytes. In vitro data show that the nontoxic concentrations of FKA (2-30 μM) significantly suppressed the proinflammatory cytokine (TNF-α, IL-1β, and IL-6) release but induced the secretion of interleukin-10 (IL-10), an anti-inflammatory cytokine. It was also shown that FKA pretreatment significantly downregulated the LPS-induced ROS production and blocked the activation of the NFκB (p65) pathway leading to the significant suppression of iNOS, COX-2, TNF-α, and IL-1β protein expressions. Notably, FKA favored the nuclear translocation of Nrf2 leading to the downstream expression of antioxidant proteins HO-1, NQO-1, and γ-GCLC via the Nrf2/ARE signaling pathway signifying the FKA’s potent antioxidant mechanism in these cells. Supporting the in vitro data, the ex vivo data obtained from primary splenocytes derived from the FKA-preadministered BALB/c mice (orally) show that FKA significantly suppressed the proinflammatory cytokine (TNF-α, IL-1β, and IL-6) secretion in control-, LPS-, or Concanavalin A- (Con A-) stimulated cells. A significant decrease in the ratios of pro- and anti-inflammatory cytokines (IL-6/IL-10; TNF-α/IL-10) showed that FKA possesses strong anti-inflammatory properties. Furthermore, BALB/c mice induced with experimental pancreatitis using cholecystokinin- (CCK-) 8 showed decreased serum lipase levels due to FKA pretreatment. We conclude that with its potent antioxidant and anti-inflammatory properties, chalcone flavokawain A could be a novel therapeutic agent in the treatment of inflammation-associated diseases.

Vascular Protective Effects of Xanthotoxin and Its Action Mechanism in Rat Aorta and Human Vascular Endothelial Cells

2020 ◽  
Vol 57 (6) ◽  
pp. 313-324
Author(s):  
Li-Hua Cao ◽  
Ho Sub Lee ◽  
Zhe-Shan Quan ◽  
Yun Jung Lee ◽  
Yu Jin
Keyword(s):  
Endothelial Cells ◽  
Cell Adhesion ◽  
Adhesion Molecule ◽  
Molecular Mechanisms ◽  
Umbilical Vein ◽  
Neuroprotective Effect ◽  
Intercellular Adhesion Molecule ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner

<b><i>Objective:</i></b> Xanthotoxin (XAT) is a linear furanocoumarin mainly extracted from the plants <i>Ammi majus</i> L. XAT has been reported the apoptosis of tumor cells, anti-convulsant, neuroprotective effect, antioxidative activity, and vasorelaxant effects. This study aimed to investigate the vascular protective effects and underlying molecular mechanisms of XAT. <b><i>Methods:</i></b> XAT’s activity was studied in rat thoracic aortas, isolated with aortic rings, and human umbilical vein endothelial cells (HUVECs). <b><i>Results:</i></b> XAT induced endothelium-dependent vasodilation in a concentration-dependent manner in the isolated rat thoracic aortas. Removal of endothelium or pretreatment of aortic rings with L-NAME, 1<i>H</i>-[1,2,4]-oxadiazolo-[4,3-<i>a</i>]-quinoxalin-1-one, and wortmannin significantly inhibited XAT-induced relaxation. In addition, treatment with thapsigargin, 2-aminoethyl diphenylborinate, Gd<sup>3+</sup>, and 4-aminopyridine markedly attenuated the XAT-induced vasorelaxation. XAT increased nitric oxide production and Akt- endothelial NOS (eNOS) phosphorylation in HUVECs. Moreover, XAT attenuated the expression of TNF-α-induced cell adhesion molecules such as intercellular adhesion molecule, vascular cell adhesion molecule-1, and E-selectin. However, this effect was attenuated by the eNOS inhibitors L-NAME and asymmetric dimethylarginine. <b><i>Conclusions:</i></b> This study suggests that XAT induces vasorelaxation through the Akt-eNOS-cGMP pathway by activating the K<sub>V</sub> channel and inhibiting the L-type Ca<sup>2+</sup> channel. Furthermore, XAT exerts an inhibitory effect on vascular inflammation, which is correlated with the observed vascular protective effects.

scholarly journals Allyl Isothiocyanate Protects Acetaminophen-Induced Liver Injury via NRF2 Activation by Decreasing Spontaneous Degradation in Hepatocyte

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3585
Author(s):  
Min Woo Kim ◽  
Ju-Hee Kang ◽  
Hyun Jin Jung ◽  
Se Yong Park ◽  
Thu Han Le Phan ◽  
...  
Keyword(s):  
Target Genes ◽  
Nuclear Translocation ◽  
Biological Effects ◽  
Allyl Isothiocyanate ◽  
Heme Oxygenase 1 ◽  
Toxic Metabolite ◽  
Related Factor ◽  
Dependent Manner ◽  
Nrf2 Activation ◽  
Nrf2 Target Gene

Acetaminophen (APAP) is one of the most frequently prescribed analgesic and anti-pyretic drugs. However, APAP-induced hepatotoxicity is a major cause of acute liver failure globally. While the therapeutic dose is safe, an overdose of APAP produces an excess of the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), subsequently resulting in hepatotoxicity. Allyl isothiocyanate (AITC), a bioactive molecule in cruciferous plants, is reported to exert various biological effects, including anti-inflammatory, anti-cancer, and anti-microbial effects. Notably, AITC is known for activating nuclear factor erythroid 2-related factor 2 (NRF2), but there is limited evidence supporting the beneficial effects on hepatocytes and liver, where AITC is mainly metabolized. We applied a mouse model in the current study to investigate whether AITC protects the liver against APAP-induced injury, wherein we observed the protective effects of AITC. Furthermore, NRF2 nuclear translocation and the increase of target genes by AITC treatment were confirmed by in vitro experiments. APAP-induced cell damage was attenuated by AITC via an NRF2-dependent manner, and rapid NRF2 activation by AITC was attributed to the elevation of NRF2 stability by decreasing its spontaneous degradation. Moreover, liver tissues from our mouse experiment revealed that AITC increases the expression of heme oxygenase-1 (HO-1), an NRF2 target gene, confirming the potential of AITC as a hepatoprotective agent that induces NRF2 activation. Taken together, our results indicate the potential of AITC as a natural-product-derived NRF2 activator targeting the liver.

scholarly journals Polygonatum sibiricum Polysaccharides Protect against MPP-Induced Neurotoxicity via the Akt/mTOR and Nrf2 Pathways

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Si Huang ◽  
Haiyan Yuan ◽  
Wenqun Li ◽  
Xinyi Liu ◽  
Xiaojie Zhang ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Neuronal Loss ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Dependent Manner ◽  
Quinone Oxidoreductase ◽  
Glutamate Cysteine Ligase ◽  
Dopaminergic Neuronal Loss

Polygonatum sibiricum, a well-known life-prolonging tonic in Chinese medicine, has been widely used for nourishing nerves in the orient, but the underlying molecular mechanisms remain unclear. In this study, we found that P. sibiricum polysaccharides (PSP) ameliorated 1-methyl-4-phenyl-1,2.3,6-tetrahydropyridine- (MPTP-) induced locomotor activity deficiency and dopaminergic neuronal loss in an in vivo Parkinson’s disease (PD) mouse model. Additionally, PSP pretreatment inhibited N-methyl-4-phenylpyridine (MPP+) induced the production of reactive oxygen species, increasing the ratio of reduced glutathione/oxidized glutathione. In vitro experiments showed that PSP promoted the proliferation of N2a cells in a dose-dependent manner, while exhibiting effects against oxidative stress and neuronal apoptosis elicited by MPP+. These effects were found to be associated with the activation of Akt/mTOR-mediated p70S6K and 4E-BP1 signaling pathways, as well as nuclear factor erythroid 2-related factor 2- (Nrf2-) mediated NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (Gclc), and glutamate-cysteine ligase modulatory subunit (Gclm), resulting in antiapoptotic and antioxidative effects. Meanwhile, PSP exhibited no chronic toxicity in C57BJ/6 mice. Together, our results suggest that PSP can serve as a promising therapeutic candidate with neuroprotective properties in preventing PD.

scholarly journals Nrf2 Regulation by Curcumin: Molecular Aspects for Therapeutic Prospects

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 167
Author(s):  
Seyed Hossein Shahcheraghi ◽  
Fateme Salemi ◽  
Niloufar Peirovi ◽  
Jamshid Ayatollahi ◽  
Waqas Alam ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Glutamate Cysteine Ligase ◽  
Response Elements ◽  
Nrf2 Signaling Pathway ◽  
Anti Inflammatory ◽  
Molecular Aspects

Nuclear factor erythroid 2 p45-related factor (2Nrf2) is an essential leucine zipper protein (bZIP) that is primarily located in the cytoplasm under physiological conditions. Nrf2 principally modulates endogenous defense in response to oxidative stress in the brain.In this regard, Nrf2 translocates into the nucleus and heterodimerizes with the tiny Maf or Jun proteins. It then attaches to certain DNA locations in the nucleus, such as electrophile response elements (EpRE) or antioxidant response elements (ARE), to start the transcription of cytoprotective genes. Many neoplasms have been shown to have over activated Nrf2, strongly suggesting that it is responsible for tumors with a poor prognosis. Exactly like curcumin, Zinc–curcumin Zn (II)–curc compound has been shown to induce Nrf2 activation. In the cancer cell lines analyzed, Zinc–curcumin Zn (II)–curc compound can also display anticancer effects via diverse molecular mechanisms, including markedly increasing heme oxygenase-1 (HO-1) p62/SQSTM1 and the Nrf2 protein levels along with its targets. It also strikingly decreases the levels of Nrf2 inhibitor, Kelch-like ECH-associated protein 1 (Keap1) protein.As a result, the crosstalk between p62/SQSTM1 and Nrf2 could be used to improve cancer patient response to treatments. The interconnected anti-inflammatory and antioxidative properties of curcumin resulted from its modulatory effects on Nrf2 signaling pathway have been shown to improve insulin resistance. Curcumin exerts its anti-inflammatory impact through suppressing metabolic reactions and proteins such as Keap1 that provoke inflammation and oxidation. A rational amount of curcumin-activated antioxidant Nrf2 HO-1 and Nrf2-Keap1 pathways and upregulated the modifier subunit of glutamate-cysteine ligase involved in the production of the intracellular antioxidant glutathione. Enhanced expression of glutamate-cysteine ligase, a modifier subunit (GLCM), inhibited transcription of glutamate-cysteine ligase, a catalytic subunit (GCLC). A variety of in vivo, in vitro and clinical studies has been done so far to confirm the protective role of curcumin via Nrf2 regulation. This manuscript is designed to provide a comprehensive review on the molecular aspects of curcumin and its derivatives/analogs via regulation of Nrf2 regulation.

PECAM-1-dependent heme oxygenase-1 regulation via an Nrf2-mediated pathway in endothelial cells

2014 ◽  
Vol 111 (06) ◽  
pp. 1077-1088 ◽  
Author(s):  
Yarúa Jaimes ◽  
Ananta Paine ◽  
Constanca Figueiredo ◽  
Britta Eiz-Vesper ◽  
Rainer Blasczyk ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Heme Oxygenase ◽  
Nuclear Translocation ◽  
Critical Role ◽  
Chinese Hamster ◽  
Human Neutrophils ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Functional Link

SummaryThe antioxidant enzyme heme oxygenase (HO)-1, which catalyses the first and rate-limiting step of heme degradation, has major anti-inflammatory and immunomodulatory effects via its cell-type-specific functions in the endothelium. In the current study, we investigated whether the key endothelial adhesion and signalling receptor PECAM-1 (CD31) might be involved in the regulation of HO-1 gene expression in human endothelial cells (ECs). To this end PECAM-1 expression was down-regulated in human umbilical vein ECs (HUVECs) by an adenoviral vector-based knockdown approach. PECAM-1 knockdown markedly induced HO-1, but not the constitutive HO isoform HO-2. Nuclear translocation of the transcription factor NF-E2-related factor-2 (Nrf2), which is a master regulator of the inducible antioxidant cell response, and intracellular levels of reactive oxygen species (ROS) were increased in PECAM-1-deficient HUVECs, respectively. PECAM-1-dependent HO-1 regulation was also examined in PECAM-1 over-expressing Chinese hamster ovary and murine L-cells. Endogenous HO-1 gene expression and reporter gene activity of transiently transfected luciferase HO-1 promoter constructs with Nrf2 target sequences were decreased in PECAM-1 over-expressing cells. Moreover, a regulatory role of ROS for HO-1 regulation in these cells is demonstrated by studies with the antioxidant N-acetylcysteine and exogenous hydrogenperoxide. Finally, direct interaction of PECAM-1 with a native complex of its binding partner NB1 (CD177) and serine proteinase 3 (PR3) from human neutrophils, markedly induced HO-1 expression in HUVECs. Taken together, we demonstrate a functional link between HO-1 gene expression and PECAM-1 in human ECs, which might play a critical role in the regulation of inflammation.

scholarly journals Antineuroinflammatory and Neuroprotective Effects of Gyejibokryeong-Hwan in Lipopolysaccharide-Stimulated BV2 Microglia

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Bo-Kyung Park ◽  
Young Hwa Kim ◽  
Yu Ri Kim ◽  
Jeong June Choi ◽  
Changsop Yang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Mitogen Activated Protein Kinase ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Neuroprotective Effects ◽  
Bv2 Cells ◽  
Bv2 Microglia ◽  
Anti Inflammatory

Microglia, the central nervous system’s innate immune cells, mediate neuroinflammation and are implicated in a variety of neuropathologies. The present study investigated the antineuroinflammatory and neuroprotective effects of Gyejibokryeong-hwan (GBH), a traditional Korean medicine, in lipopolysaccharide- (LPS-) stimulated murine BV2 microglia. BV2 cells were pretreated with GBH, fluoxetine (FXT), or amitriptyline (AMT) for 1 h and then stimulated with LPS (100 ng/mL). The expression levels of nitric oxide (NO), cytokines, and chemokines were determined by the Griess method, ELISA, or real-time PCR. Western blotting was used to measure various transcription factors and mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/Akt activity. GBH significantly reduced the levels of NO, inducible nitric oxide synthase (iNOS), cyclooxygenase- (COX-) 2, tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1β, IL-6, macrophage inhibitory protein- (MIP-) 1α, macrophage chemoattractant protein- (MCP-) 1, and IFN-γ inducible protein- (IP-) 10, regulated upon activation normal T cell expressed sequence (RANTES) in a dose-dependent manner. Expression of nuclear factor- (NF-) κB p65 was significantly decreased and phosphorylation of extracellular signal-regulated kinase (Erk), c-Jun NH2-terminal kinase (JNK), and PI3K/Akt by GBH, but not p38 MAPK, was decreased. Furthermore, production of anti-inflammatory cytokine IL-10 was increased and Heme oxygenase-1 (HO-1) was upregulated via the nuclear factor-E2-related factor 2 (NRF2)/cAMP response element-binding protein (CREB) pathway, collectively indicating the neuroprotective effects of GBH. We concluded that GBH may suppress neuroinflammatory responses by inhibiting NF-κB activation and upregulating the neuroprotective factor, HO-1. These results suggest that GBH has potential as anti-inflammatory and neuroprotective agents against microglia-mediated neuroinflammatory disorders.

scholarly journals Thymoquinone Prevents Dopaminergic Neurodegeneration by Attenuating Oxidative Stress Via the Nrf2/ARE Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Jianjian Dong ◽  
Xiaoming Zhang ◽  
Shijing Wang ◽  
Chenchen Xu ◽  
Manli Gao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nuclear Translocation ◽  
Nigella Sativa ◽  
Drug Candidate ◽  
Heme Oxygenase 1 ◽  
Related Factor ◽  
Protective Effects ◽  
Quinone Oxidoreductase ◽  
Neuroprotective Effects ◽  
Antioxidant Genes

Studies have indicated that oxidative stress plays a crucial role in the development of Parkinson’s disease (PD) and other neurodegenerative conditions. Research has also revealed that nuclear factor erythroid 2-related factor 2 (Nrf2) triggers the expression of antioxidant genes via a series of antioxidant response elements (AREs), thus preventing oxidative stress. Thymoquinone (TQ) is the bioactive component of Nigella sativa, a medicinal plant that exhibits antioxidant and neuroprotective effects. In the present study we examined whether TQ alleviates in vivo and in vitro neurodegeneration induced by 1-methyl-4-phenylpyridinium (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) by acting as an activator of the Nrf2/ARE cascade. We showed that TQ significantly reduced MPP+-mediated cell death and apoptosis. Moreover, TQ significantly elevated the nuclear translocation of Nrf2 and significantly increased the subsequent expression of antioxidative genes such as Heme oxygenase 1 (HO-1), quinone oxidoreductase (NQO1) and Glutathione-S-Transferase (GST). The application of siRNA to silence Nrf2 led to an abolishment in the protective effects of TQ. We also found that the intraperitoneal injection of TQ into a rodent model of PD ameliorated oxidative stress and effectively mitigated nigrostriatal dopaminergic degeneration by activating the Nrf2-ARE pathway. However, these effects were inhibited by the injection of a lentivirus wrapped Nrf2 siRNA (siNrf2). Collectively, these findings suggest that TQ alleviates progressive dopaminergic neuropathology by activating the Nrf2/ARE signaling cascade and by attenuating oxidative stress, thus demonstrating that TQ is a potential novel drug candidate for the treatment of PD.

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