Sinapic Acid Attenuates the Neuroinflammatory Response by Targeting AKT and MAPK in LPS-Activated Microglial Models

Sinapic acid (SA) is a phenolic acid that is widely distributed in fruits and vegetables, which has various bioactivities, such as antidiabetic, anticancer and anti-inflammatory functions. Over-activated microglial is involved in the development progress of neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease. The objective of this study was to investigate the effect of SA in microglia neuroinflammation models. Our results demonstrated that SA inhibited secretion of the nitric oxide (NO) and interleukin (IL)-6, reduced the expression of inducible nitric oxide synthase (iNOS) and enhanced the release of IL-10 in a dose-dependent manner. Besides, our further investigation revealed that SA attenuated the phosphorylation of AKT and MAPK cascades in LPS-induced microglia. Consistently, oral administration of SA in mouse regulated the production of inflammationrelated cytokines and also suppressed the phosphorylation of MAPK cascades and AKT in the mouse cerebral cortex. These results suggested that SA may be a possible therapy candidate for anti-inflammatory activity by targeting the AKT/MAPK signaling pathway.

Neuroprotective Effect of Astersaponin I against Parkinson’s Disease through Autophagy Induction

An active compound, triterpene saponin, astersaponin I (AKNS-2) was isolated from Aster koraiensis Nakai (AKNS) and the autophagy activation and neuroprotective effect was investigated on in vitro and in vivo Parkinson’s disease (PD) models. The autophagy-regulating effect of AKNS-2 was monitored by analyzing the expression of autophagy-related protein markers in SHSY5Y cells using Western blot and fluorescent protein quenching assays. The neuroprotection of AKNS-2 was tested by using a 1-methyl-4-phenyl-2,3-dihydropyridium ion (MPP+ )-induced in vitro PD model in SH-SY5Y cells and an MPTP-induced in vivo PD model in mice. The compound-treated SH-SY5Y cells not only showed enhanced microtubule-associated protein 1A/1B-light chain 3-II (LC3-II) and decreased sequestosome 1 (p62) expression but also showed increased phosphorylated extracellular signal–regulated kinases (p-Erk), phosphorylated AMP-activated protein kinase (p-AMPK) and phosphorylated unc-51-like kinase (p-ULK) and decreased phosphorylated mammalian target of rapamycin (p-mTOR) expression. AKNS-2-activated autophagy could be inhibited by the Erk inhibitor U0126 and by AMPK siRNA. In the MPP+ -induced in vitro PD model, AKNS-2 reversed the reduced cell viability and tyrosine hydroxylase (TH) levels and reduced the induced α-synuclein level. In an MPTP-induced in vivo PD model, AKNS-2 improved mice behavioral performance, and it restored dopamine synthesis and TH and α-synuclein expression in mouse brain tissues. Consistently, AKNS-2 also modulated the expressions of autophagy related markers in mouse brain tissue. Thus, AKNS-2 upregulates autophagy by activating the Erk/mTOR and AMPK/mTOR pathways. AKNS-2 exerts its neuroprotective effect through autophagy activation and may serve as a potential candidate for PD therapy.

3’-O-Acetyl-24-Epi-7,8-Didehydrocimigenol-3-O-β-DXylopryranoside Decreases Amyloid Beta Production in Amyloid Precursor Protein-Transfected HeLa Cells

Extracellular beta amyloid (Aβ) plaques are the neuropathological hallmarks of Alzheimer’s disease (AD). Accordingly, reducing Aβ levels is considered a promising strategy for AD prevention. 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside significantly decreased the Aβ production and this effect was accompanied with reduced sAPPβ production known as a soluble ectodomain APP fragment through β-secretases in HeLa cells overexpressing amyloid precursor proteins (APPs). This compound also increased the level of sAPPα, which is a proteolytic fragment of APP by α-secretases. In addition, 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside decreased the protein level of β-secretases, but the protein levels ofA disintegrin and metalloproteinase (ADAM) family, especially ADAM10 and ADAM17, are increased. Thus, 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside could be useful in the development of AD treatment in the aspect of amyloid pathology.

3’-O-Acetyl-24-Epi-7,8-Didehydrocimigenol-3-O-β-DXylopryranoside Decreases Amyloid Beta Production in Amyloid Precursor Protein-Transfected HeLa Cells

Extracellular beta amyloid (Aβ) plaques are the neuropathological hallmarks of Alzheimer’s disease (AD). Accordingly, reducing Aβ levels is considered a promising strategy for AD prevention. 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside significantly decreased the Aβ production and this effect was accompanied with reduced sAPPβ production known as a soluble ectodomain APP fragment through β-secretases in HeLa cells overexpressing amyloid precursor proteins (APPs). This compound also increased the level of sAPPα, which is a proteolytic fragment of APP by α-secretases. In addition, 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside decreased the protein level of β-secretases, but the protein levels ofA disintegrin and metalloproteinase (ADAM) family, especially ADAM10 and ADAM17, are increased. Thus, 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside could be useful in the development of AD treatment in the aspect of amyloid pathology.

Anti-neuroinflammatory Effects of 12-Dehydrogingerdione in LPS-Activated Microglia through Inhibiting Akt/IKK/NF-κB Pathway and Activating Nrf-2/HO-1 Pathway

Ginger, one of worldwide consumed dietary spice, is not only famous as food supplements, but also believed to exert a variety of remarkable pharmacological activity as herbal remedies. In this study, a ginger constituent, 12-dehydrogingerdione (DHGD) was proven that has comparable anti-inflammatory activity with positive control 6-shogaol in inhibiting LPS-induced interleukin (IL)-6, tumor necrosis factor (TNF)-α, prostaglandin (PG) E₂, nitric oxide (NO), inducible NO synthase (iNOS) and cyclooxygenase (COX)-2, without interfering with COX-1 in cultured microglial cells. Subsequent mechanistic studies indicate that 12-DHGD may inhibit neuro-inflammation through suppressing the LPS-activated Akt/IKK/NF-κB pathway. Furthermore, 12-DHGD markedly promoted the activation of NF-E2-related factor (Nrf)-2 and heme oxygenase (HO)-1, and we demonstrated that the involvement of HO-1 on the production of pro-inflammatory mediators such as NO and TNF-α by using a HO-1 inhibitor, Zinc protoporphyrin (Znpp). These results indicate that 12-DHGD may protect against neuro-inflammation by inhibiting Akt/IKK/IκB/NF-κB pathway and promoting Nrf-2/HO-1 pathway.

Justicidin A Reduces β-Amyloid via Inhibiting Endocytosis of β-Amyloid Precursor Protein

β-amyloid precursor protein (APP) can be cleaved by α-, and γ-secretase at plasma membrane producing soluble ectodomain fragment (sAPPα). Alternatively, following endocytosis, APP is cleaved by β-, and γ-secretase at early endosomes generating β-amyloid (Aβ), the main culprit in Alzheimer's disease (AD). Thus, APP endocytosis is critical for Aβ production. Recently, we reported that Monsonia angustifolia, the indigenous vegetables consumed in Tanzania, improved cognitive function and decreased Aβ production. In this study, we examined the underlying mechanism of justicidin A, the active compound of M. angustifolia, on Aβ production. We found that justicidin A reduced endocytosis of APP, increasing sAPPα level, while decreasing Aβ level in HeLa cells overexpressing human APP with the Swedish mutation. The effect of justicidin A on Aβ production was blocked by endocytosis inhibitors, indicating that the decreased APP endocytosis by justicidin A is the underlying mechanism. Thus, justicidin A, the active compound of M. angustifolia, may be a novel agent for AD treatment.

Neuroprotective Effect of Chebulagic Acid via Autophagy Induction in SH-SY5Y Cells

Autophagy is a series of catabolic process mediating the bulk degradation of intracellular proteins and organelles through formation of a double-membrane vesicle, known as an autophagosome, and fusing with lysosome. Autophagy plays an important role of death-survival decisions in neuronal cells, which may influence to several neurodegenerative disorders including Parkinson's disease. Chebulagic acid, the major constituent of Terminalia chebula and Phyllanthus emblica, is a benzopyran tannin compound with various kinds of beneficial effects. This study was performed to investigate the autophagy enhancing effect of chebulagic acid on human neuroblastoma SH-SY5Y cell lines. We determined the effect of chebulagic acid on expression levels of autophagosome marker proteins such as, DOR/TP53INP2, Golgi-associated ATPase Enhancer of 16 kDa (GATE 16) and Light chain 3 II (LC3 II), as well as those of its upstream pathway proteins, AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Beclin-1. All of those proteins were modulated by chebulagic acid treatment in a way of enhancing the autophagy. Additionally in our study, chebulagic acid also showed a protective effect against 1-methyl-4-phenylpyridinium (MPP+) - induced cytotoxicity which mimics the pathological symptom of Parkinson's disease. This effect seems partially mediated by enhanced autophagy which increased the degradation of aggregated or misfolded proteins from cells. This study suggests that chebulagic acid is an attractive candidate as an autophagy-enhancing agent and therefore, it may provide a promising strategy to prevent or cure the diseases caused by accumulation of abnormal proteins including Parkinson's disease.

The Pharmacokinetic Interaction and Therapeutic Plasma Concentration of Oxcarvazepine / 대한간질학회지

PURPOSE: Oxcarbazepine (OXC) is chemically related to carbamazepine (CBZ). OZC exerts less liver enzyme induction than CBZ and is completely metabolized by reduction to the active metabolite, 10, 11-dihydro-10-hydroxy-5H-dibenzo (b,f) azepine-5-carboxamide (MHD). It was known that OXC had no significant pharmacokinetic interactions with other antiepileptic drugs. But it is not thoroughly studied yet because of short duration of clinical application. We investigated whether the plasma concentration of OXC metabolite (MHD) is changed by valproic acid compared with OXC monotherapy and studied the correlation of the dose of OXC with the plasma concentration of its active metabolite (MHD). METHODS: The patient with OXC monotherapy (19 cases) and patients with OXC and valproic acid(16 cases) were incluses. We analyzed the level of its metabolites MHD by HPLC RESULTS: The plasma concerntration of MHD in OXC monotherapy is 15.5+/-3.2 microgram/ml and that of the MHD in polytherapy with valproic acid is 16.4+/-3.4 microgram/ml at the same dose of OXC. The plasma concentration of MHD is ranged from 7.4 microgram/ml at 600 mg/day of OXC to 27.0 microgram/ml at 1800 mg/day of OXC and highly correlated with OXC dose per body weight (r=0.72-84). CONCLUSION: There is no significant change or difference of MHD plasma concentraion between OXC monotherapy and polytherapy with valproic acid at the same dose of OXC. THe plasma concentration of MHD is highly correlated with OXC dose per body weight.

Detection of Antibodies against Shope Fibroma Virus and Formation of Fibroma in the Korean Domestic Rabbits

In our preliminary study to find antiviral or antitumor agents from Korean natural products, we found that the Shope fibroma virus (SFV) induced fibromas reaching maximum size at 5~6 days with spontaneous disappearance at 15~20 days after SFV intracutaneous inoculation into Korean domestic rabbits. However, the sizes of fibromas of rabbits at day 5 after virus inoculation were significantly different individually. Assuming that the variation of tumor size was due to either susceptibility or the preexisting antibodies against SFV in the Korean domestic rabbits, the rabbits were checked for the antibodies against SFV by IFAT using SFV infected RKl3 cells. The antibody positive rate of normal Korean domestic rabbits was 32.8% and the sizes of the fibromas of the positive rabbits were significantly smaller than those of negative rabbits (p<0.0001). The fibroma sizes were dependent on the antibody titers of rabbits to SFV. The sizes of fibromas after inoculation of SFV into immunized rabbits were about one tenth of those by the first inoculation into normal rabbits. This is the first report on the antibody prevalence against SFV among normal Korean domestic rabbits and it suggest the existence of a wild fibroma virus or related virus in Korea.