• Nutrition Research and Practice
• /
• v.14 no.6
• /
• pp.593-605
• /
• 2020

BACKGROUND/OBJECTIVES: Alzheimer's disease is common age-related neurodegenerative condition characterized by amyloid beta (Aβ) accumulation that leads cognitive impairment. In the present study, we investigated the protective effect of paeoniflorin (PF) against Aβ-induced neuroinflammation and the underlying mechanism in C6 glial cells. MATERIALS/METHODS: C6 glial cells were treated with PF and Aβ_25-35, and cell viability, nitric oxide (NO) production, and pro-inflammatory cytokine release were measured. Furthermore, the mechanism underlying the effect of PF on inflammatory responses and Aβ degradation was determined by Western blot. RESULTS: Aβ_25-35 significantly reduced cell viability, but this reduction was prevented by the pretreatment with PF. In addition, PF significantly inhibited Aβ_25-35-induced NO production in C6 glial cells. The secretion of interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha was also significantly reduced by PF. Further mechanistic studies indicated that PF suppressed the production of these pro-inflammatory cytokines by regulating the nuclear factor-kappa B (NF-κB) pathway. The protein levels of inducible NO synthase and cyclooxygenase-2 were downregulated and phosphorylation of NF-κB was blocked by PF. However, PF elevated the protein expression of inhibitor kappa B-alpha and those of Aβ degrading enzymes, insulin degrading enzyme and neprilysin. CONCLUSIONS: These findings indicate that PF exerts protective effects against Aβ-mediated neuroinflammation by inhibiting NF-κB signaling, and these effects were associated with the enhanced activity of Aβ degradation enzymes.

• Journal of Marine Bioscience and Biotechnology
• /
• v.12 no.1
• /
• pp.29-39
• /
• 2020

In this study, we investigated the inhibitory potential of an ethanol extract of Carpomitra costata (EECC) (Stackhouse) Batters, a brown alga, against neuroinflammatory responses in lipopolysaccharide (LPS)-stimulated BV2 microglia. Our results showed that EECC significantly suppressed the LPS-induced secretion of pro-inflammatory mediators, including nitric oxide (NO) and prostaglandin E₂, with no significant cytotoxic effects. EECC also inhibited the LPS-induced expression of their regulatory enzymes, such as inducible NO synthase and cyclooxygenase-2. In addition, EECC downregulated the LPS-induced expression and production of the proinflammatory cytokines, tumor necrosis factor-α and interleukin-1β. In the mechanistic assessment of the antineuroinflammatory effects, EECC was found to inhibit the nuclear translocation and DNA binding of nuclear factor-kappa B (NF-κB) by disrupting the degradation of the κB-α inhibitor in the cytoplasm. Moreover, EECC effectively suppressed the enhanced expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88, as well as the binding of LPS to TLR4 in LPS-treated BV2 cells. Furthermore, EECC markedly reduced the LPS-induced generation of reactive oxygen species (ROS), demonstrating a strong antioxidative effect. Collectively, these results suggest that EECC repressed LPS-mediated inflammatory action in the BV2 microglia through the inactivation of NF-κB signaling by antagonizing TLR4 and/or preventing ROS accumulation. While further studies are needed to fully understand the anti-inflammatory effects associated with the antioxidant activity of EECC, the current findings suggest that EECC has a potential advantage in inhibiting the onset and treatment of neuroinflammatory diseases.

• Biomolecules & Therapeutics
• /
• v.28 no.2
• /
• pp.152-162
• /
• 2020

Cerebral ischemia exhibits a multiplicity of pathophysiological mechanisms. During ischemic stroke, the reactive oxygen species (ROS) concentration rises to a peak during reperfusion, possibly underlying neuronal death. Recombinant human erythropoietin (EPO) supplementation is one method of treating neurodegenerative disease by reducing the generation of ROS. We investigated the therapeutic effect of PEGylated EPO (P-EPO) on ischemic stroke. Mice were administered P-EPO (5,000 U/kg) via intravenous injection, and middle cerebral artery occlusion (MCAO) followed by reperfusion was performed to induce in vivo ischemic stroke. P-EPO ameliorated MCAO-induced neurological deficit and reduced behavioral disorder and the infarct area. Moreover, lipid peroxidation, expression of inflammatory proteins (cyclooxygenase-2 and inducible nitric oxide synthase), and cytokine levels in blood were reduced by the P-EPO treatment. In addition, higher activation of nuclear factor kappa B (NF-κB) was found in the brain after MCAO, but NF-κB activation was reduced in the P-EPO-injected group. Treatment with the NF-κB inhibitor PS-1145 (5 mg/kg) abolished the P-EPO-induced reduction of infarct volume, neuronal death, neuroinflammation, and oxidative stress. Moreover, P-EPO was more effective than EPO (5,000 U/kg) and similar to a tissue plasminogen activator (10 mg/kg). An in vitro study revealed that P-EPO (25, 50, and 100 U/mL) treatment protected against rotenone (100 nM)-induced neuronal loss, neuroinflammation, oxidative stress, and NF-κB activity. These results indicate that the administration of P-EPO exerted neuroprotective effects on cerebral ischemia damage through anti-oxidant and anti-inflammatory properties by inhibiting NF-κB activation.

• Biomolecules & Therapeutics
• /
• v.18 no.4
• /
• pp.463-468
• /
• 2010

T-cell activation depends on signals received by the T-cell receptor and CD28 co-stimulatory receptor. Since B7.1 and B7.2 molecules expressed on the surface of antigen presenting cells provide co-stimulatory signals through CD28 to T-cells, an inhibitor of CD28-B7.1/B7.2 binding has been proposed as a therapeutic agent for suppression of excessive T-cell activity. Although anti-B7.1/B7.2 antibodies are known to block B7.1 and B7.2 molecules, their effects on intracellular events in antigen presenting cells remain unclear. In this study, anti-B7.1/B7.2 antibodies decreased secretion of nitric oxide and pro-inflammatory cytokines such as TNF-$\alpha$, IL-$1{\beta}$, and IL-12 in LPS-activated RAW264.7 macrophage-like cells and peritoneal macrophages. Moreover, anti-B7.1/B7.2 antibodies inhibited $I{\kappa}B{\alpha}$ phosphorylation and down-regulated expression of co-stimulatory molecules including B7.1, B7.2, and PD-L1 in LPS-stimulated peritoneal macrophages. These findings suggest that CTLA4-Ig and anti-B7.1/B7.2 antibodies may be candidates to treat chronic inflammatory diseases and autoimmune responses caused by excessive activation of both T-cells and macrophages.

• Herbal Formula Science
• /
• v.25 no.4
• /
• pp.537-551
• /
• 2017

Objectives : Jinnoe-san (JNS) is a novel herbal formula consisting of five oriental medicinal herbs including Polygalae Radix, Prunellae Spica, Perillae Herba, Betulae Cortex, and Lonicerae Flos. In this study, we investigated the effects and molecular mechanism of JNS on Parkinson's disease in vitro model. Methods : The effects of JNS on 1-methyl-4-phenylpyridinium ($MPP^+$)-induced cell death in SH-SY5Y cells were evaluated with a cell viability assay, flow cytometry, and western blots analysis. The effects of JNS on lipopolysaccharide (LPS)-stimulated BV2 microglia were determined with a nitric oxide (NO) assay, enzyme linked immunosorbent assays, and western blots analysis. Result : $MPP^+$-induced cell death in SH-SY5Y cells was significantly reduced by JNS pre-treatment in a dose-dependent manner. JNS inhibited the production of reactive oxygen species, mitochondria dysfunction, and apoptosis induced by $MPP^+$ in SH-SY5Y cells. Furthermore, JNS significantly activated Akt and ERK in SH-SY5Y cells and the ability of JNS to prevent mitochondria dysfunction by $MPP^+$ was antagonized by pre-treatment of LY294002 and PD98059, an Akt and ERK inhibitor, respectively. In addition, JNS inhibited LPS-induced NO and $PGE_2$ production as well as iNOS expression and secretion of TNF-${\alpha}$, pro-inflammatory cytokines without affecting the cell viability. JNS also suppressed LPS-induced ERK activation. Conclusions : These results demonstrate that JNS has a protective effect on the dopaminergic neurons against $MPP^+$-induced neurotoxicity and anti-inflammatory effect on the LPS-stimulated microglia. These findings provide evidences for JNS to be considered as a new prescription for treating Parkinson's disease.

• Herbal Formula Science
• /
• v.25 no.4
• /
• pp.471-481
• /
• 2017

Objectives : Noemyeong-san (NMS) is a novel herbal prescription composed of five oriental medicinal herbs including Prunellae Spica, Betulae Cortex, Foeniculi Fructus, Asiasari Radix, and Clematidis Radix for treating Alzheimer's disease. In the present study, we investigated the effects and molecular mechanisms of NMS on BV2 microglia to evaluate the potential action of this formula for preventing or treating neurodegenerative disease such as Alzheimer's disease. Methods : To determine the cytotoxicity of NMS on BV2 microglia, the MTT assay was performed. The effects of NMS on lipopolysaccharide (LPS)-stimulated BV2 microglia were determined with a nitric oxide (NO) assay and western blots for inflammatory mediator-related proteins, mitogen activated protein kinases (MAPKs), nuclear factor kappa B (NF-${\kappa}B$) pathway-related proteins, and heme oxygenase-1 (HO-1). Result : NMS inhibited induction of iNOS and COX-2 as well as NO production without affecting the cell viability in LPS-stimulated BV2 microglia. NMS also suppressed activation of ERK and p38 MAPK among main kinases of MAPKs as well as NF-${\kappa}B$ by LPS stimulation. Furthermore, NMS dose-dependently induced the expression of HO-1 and the inhibitory effect of NMS on the production of NO were blocked by pretreatment with an HO-1 inhibitor, Snpp. Conclusions : These results demonstrate that NMS has potent anti-neuroinflammatory effect on the LPS-stimulated microglia. These findings provide evidences for NMS to be considered as a new prescription for preventing or treating neurodegenerative disease such as Alzheimer's disease.

• Toxicological Research
• /
• v.22 no.3
• /
• pp.293-299
• /
• 2006

We demonstrate that magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells(murine macrophage cell line). Treatment of RAW 264.7 cells with magnolol inhibited LPS-stimulated nitric oxide production in a dose-related manner. RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression. Western immunoblot analysis of phosphorylate p38 kinase showed magnolol significantly inhibited the phosphorylation of p38 kinase which is important in the regulation of iNOS gene expression. The specific p38 inhibiter SB203580 abrogated the LPS-induced NO generation and iNOS expression, whereas the selective MEK-1 inhibitor PD98059 did not affect the NO induction. Immunostaining of p65 and reporter gene assay showed that magnolol inhibited NF-${\kappa}/Rel$ nuclear translocation and transcriptional activation, respectively. Collectively, this series of experiments indicates that magnolol inhibits iNOS gene expression by blocking NF-k/Rel and p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of magnolol or iNOS suggest that magnolol may represent a useful anti-inflammatory agent.

• Clinical and Experimental Pediatrics
• /
• v.56 no.3
• /
• pp.116-124
• /
• 2013

Purpose: Tumor necrosis factor (TNF)-${\alpha}$ is thought to contribute to pulmonary hypertension. We aimed to investigate the effect of infliximab (TNF-${\alpha}$ antagonist) treatment on pathologic findings and gene expression in a monocrotaline-induced pulmonary hypertension rat model. Methods: Six-week-old male Sprague-Dawley rats were allocated to 3 groups: control (C), single subcutaneous injection of normal saline (0.1 mL/kg); monocrotaline (M), single subcutaneous injection of monocrotaline (60 mg/kg); and monocrotaline + infliximab (M+I), single subcutaneous injection of monocrotaline plus single subcutaneous injection of infliximab (5 mg/kg). The rats were sacrificed after 1, 5, 7, 14, or 28 days. We examined changes in pathology and gene expression levels of TNF-${\alpha}$, endothelin-1 (ET-1), endothelin receptor A (ERA), endothelial nitric oxide synthase (eNOS), matrix metalloproteinase (MMP) 2, and tissue inhibitor of matrix metalloproteinase (TIMP). Results: The increase in medial wall thickness of the pulmonary arteriole in the M+I group was significantly lower than that in the M group on day 7 after infliximab treatment (P<0.05). The number of intraacinar muscular arteries in the M+I group was lower than that in the M group on days 14 and 28 (P<0.05). Expression levels of TNF-${\alpha}$, ET-1, ERA, and MMP2 were significantly lower in the M+I group than in the M group on day 5, whereas eNOS and TIMP expressions were late in the M group (day 28). Conclusion: Infliximab administration induced early changes in pathological findings and expression levels of TNF-${\alpha}$, and MMP2 in a monocrotaline-induced pulmonary hypertension rat model.

• The Korean Journal of Physiology and Pharmacology
• /
• v.20 no.6
• /
• pp.641-647
• /
• 2016

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by vascular remodeling of pulmonary arteries (PAs) and increased vascular resistance in the lung. Monocrotaline (MCT), a toxic alkaloid, is widely used for developing rat models of PAH caused by injury to pulmonary endothelial cells; however, characteristics of vascular functions in MCT-induced PAH vary and are not fully understood. Here, we investigated hypoxic pulmonary vasoconstriction (HPV) responses and effects of various vasoconstrictors with isolated/perfused lungs of MCT-induced PAH (PAH-MCT) rats. Using hematoxylin and eosin staining, we confirmed vascular remodeling (i.e., medial thickening of PA) and right ventricle hypertrophy in PAH-MCT rats. The basal pulmonary arterial pressure (PAP) and PAP increase by a raised flow rate (40 mL/min) were higher in the PAH-MCT than in the control rats. In addition, both high $K^+$ (40 mM KCl)- and angiotensin II-induced PAP increases were higher in the PAH-MCT than in the control rats. Surprisingly, application of a nitric oxide synthase inhibitor, L-$N^G$-Nitroarginine methyl ester (L-NAME), induced a marked PAP increase in the PAH-MCT rats, suggesting that endothelial functions were recovered in the three-week PAH-MCT rats. In addition, the medial thickening of the PA was similar to that in chronic hypoxia-induced PAH (PAH-CH) rats. However, the HPV response (i.e., PAP increased by acute hypoxia) was not affected in the MCT rats, whereas HPV disappeared in the PAH-CH rats. These results showed that vascular contractility and HPV remain robust in the MCT-induced PAH rat model with vascular remodeling.

• Nutrition Research and Practice
• /
• v.10 no.4
• /
• pp.371-376
• /
• 2016

BACKGROUND/OBJECTIVES: Chronic ultraviolet (UV) exposure-induced reactive oxygen species (ROS) are commonly involved in the pathogenesis of skin damage by activating the metalloproteinases (MMP) that break down type I collagen. Adenophora remotiflora (AR) is a perennial wild plant that inhabits Korea, China, and Japan. The present study investigated the protective effects of AR against UVB-induced photo-damage in keratinocytes. MATERIALS/METHODS: An in vitro cell-free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and nitric oxide (NO). The effect of AR on ROS formation, antioxidant enzymes, elastase, MMP-1 level, and mRNA expression of MMP-1 were determined in UVB-irradiated human keratinocyte HaCaT cells. RESULTS: AR demonstrated strong DPPH free radical and NO scavenging activity in a cell-free system exhibiting $IC_{50}$ values of 1.88 mg/mL and 6.77 mg/mL, respectively. AR pretreatment dose-dependently attenuated the production of UVB-induced intracellular ROS, and antioxidant enzymes (catalase and superoxide dismutase) were enhanced in HaCaT cells. Furthermore, pretreatment of AR prevented UVB-induced elastase and collagen degradation by inhibiting the MMP-1 protein level and mRNA expression. Accordingly, AR treatment elevated collagen content in UVB-irradiated HaCaT cells. CONCLUSION: The present study provides the first evidence of AR inhibiting UVB-induced ROS production and induction of MMP-1 as a result of augmentation of antioxidative activity in HaCaT human keratinocytes. These results suggest that AR might act as an effective inhibitor of UVB-modulated signaling pathways and might serve as a photo-protective agent.