Human albumin prevents 6-hydroxydopamine-induced loss of tyrosine hydroxylase in in vitro and in vivo

IRE1/JNK Is the Leading UPR Pathway in 6-OHDA-Induced Degeneration of Differentiated SH-SY5Y Cells

Parkinson's disease (PD) is a neurodegenerative disorder which affects dopaminergic neurons of the midbrain. Accumulation of α-synuclein or exposure to neurotoxins like 6-hydroxydopamine (6-OHDA) induces endoplasmic reticulum (ER) stress along with the unfolded protein response (UPR), which executes apoptosis via activation of PERK/CHOP or IRE1/JNK signaling. The present study aimed to determine which of these pathways is a major contributor to neurodegeneration in an 6-OHDA-induced in vitro model of PD. For this purpose, we have applied pharmacological PERK and JNK inhibitors (AMG44 and JNK V) in differentiated SH-SY5Y cells exposed to 6-OHDA. Inhibition of PERK and JNK significantly decreased genotoxicity and improved mitochondrial respiration, but only JNK inhibition significantly increased cell viability. Gene expression analysis revealed that the effect of JNK inhibition was dependent on a decrease in MAPK10 and XBP1 mRNA levels, whereas inhibition of either PERK or JNK significantly reduced the expression of DDIT3 mRNA. Western blot has shown that JNK inhibition strongly induced the XBP1s protein, and inhibition of each pathway attenuated the phosphorylation of eIF2α and JNK, as well as the expression of CHOP. Collectively, our data suggests that targeting the IRE1/JNK pathway of the UPR is a more effective option for PD treatment as it simultaneously affects more than one pro-apoptotic pathway.

Polyphenolic Glycosides from the Fruits Extract of Lycium ruthenicum Murr and Their Monoamine Oxidase B Inhibitory and Neuroprotective Activities

The fruits ofLycium ruthenicum Murr have long been consumed as health food and used in folk medicine in China. Apart from the well-known polysaccharides, the active small molecular constituents in this fruit have not been fully studied. In this work, a systematic phytochemical study was carried out to investigate the small molecules and their potential health benefits. Nine new polyphenolic glycosides, lyciumserin A-I (1-9), together with 16 known compounds (10-25), were isolated and elucidated by high-resolution electrospray ionization mass spectrometry and comprehensive NMR analyses in combination with chemical hydrolysis. Compounds 1, 2, and 16 exhibited moderate inhibitory activity of monoamine oxidase B (MAO-B), while compounds 1 (50 μM) and 2 (100 μM) displayed significant neuroprotective effects (69.22 and 72.38% of cell viability, respectively) in the 6-hydroxydopamine-induced injury of the PC12 cell model (54.41%), comparable to the positive drug rasagiline (70.45%). The neuroprotective effect of 1 and 2 was further evidenced by the observation of the morphological change and fluorescein diacetate/propidium iodide staining. In addition, the levels of the major active compounds (1, 3, 5/6, and 16-18) vary from 21.5 to 892.3 μg/g. This is the first report on phenolic glycosides from the fruits ofL. ruthenicum Murr that possess both significant MAO-B inhibitory and neuroprotective effects, indicating the promising potential of the fruits for the development of health care products and even therapeutic agents for the treatment of Parkinson's disease and other neurodegenerative diseases.

Plasma exchange with albumin replacement and disease progression in amyotrophic lateral sclerosis: a pilot study

Background

Plasma exchange (PE) is used to treat a range of neurological disorders. Based on results demonstrated in Alzheimer’s disease, we theorized that PE with albumin replacement (PE-A) might alter the metabolic profile of plasma and cerebrospinal fluid in patients with amyotrophic lateral sclerosis (ALS) by removing disease-inducing molecules. The aim of this study was to evaluate the effect of PE-A on disease progression in ALS.

Methods

In this open-label, non-controlled, single-arm, prospective pilot study, 13 adults with ALS had 6 months’ treatment with PE-A 5% and 6 months’ follow-up. Primary endpoints were changes from baseline in the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) score and forced vital capacity (FVC) through 48 weeks. A post hoc analysis compared individual patient data with the expected ALSFRS-R progression slope.

Results

The median ALSFRS-R score declined throughout the study, although the rate of decline was slower than expected in seven patients at treatment end and in five patients at study end. Six patients remained in the same baseline slope progression category, and four patients improved their slope category at treatment end. Median FVC decreased significantly during the study. Treatment was well tolerated. Of 330 PE-A procedures, 0.9% were associated with potentially related adverse events.

Conclusion

Although functional impairment progressed, about two-thirds of patients showed a slower than expected rate of decline at treatment end. Most patients had unaltered (54.5%) or reduced (36.4%) ALSFRS-R slope progression at treatment end. Further evaluation of PE-A in controlled studies involving more patients is warranted.

EudraCT number

2013-004842-40.

Trial registration

ClinicalTrials.gov identifier: NCT02479802.

Melatonin Analogues Potently Inhibit MAO-B and Protect PC12 Cells against Oxidative Stress

Monoamine oxidase B (MAO-B) metabolizes dopamine and plays an important role in oxidative stress by altering the redox state of neuronal and glial cells. MAO-B inhibitors are a promising therapeutical approach for Parkinson’s disease (PD). Herein, 24 melatonin analogues (3a–x) were synthesized as novel MAO-B inhibitors with the potential to counteract oxidative stress in neuronal PC12 cells. Structure elucidation, characterization, and purity of the synthesized compounds were performed using ¹H-NMR, ¹³C-NMR, HRMS, and HPLC. At 10 µM, 12 compounds showed >50% MAO-B inhibition. Among them, compounds 3n, 3r, and 3u–w showed >70% inhibition of MAO-B and IC₅₀ values of 1.41, 0.91, 1.20, 0.66, and 2.41 µM, respectively. When compared with the modest selectivity index of rasagiline (II, a well-known MAO-B inhibitor, SI > 50), compounds 3n, 3r, 3u, and 3v demonstrated better selectivity indices (SI > 71, 109, 83, and 151, respectively). Furthermore, compounds 3n and 3r exhibited safe neurotoxicity profiles in PC12 cells and reversed 6-OHDA- and rotenone-induced neuronal oxidative stress. Both compounds significantly up-regulated the expression of the anti-oxidant enzyme, heme oxygenase (HO)-1. Treatment with Zn(II)-protoporphyrin IX (ZnPP), a selective HO-1 inhibitor, abolished the neuroprotective effects of the tested compounds, suggesting a critical role of HO-1 up-regulation. Both compounds increased the nuclear translocation of Nrf2, which is a key regulator of the antioxidative response. Taken together, these data show that compounds 3n and 3r could be further exploited for their multi-targeted role in oxidative stress-related PD therapy.

Monoterpenoid indole alkaloids with potential neuroprotective activities from the stems and leaves of Melodinus cochinchinensis

A chemical study on the stems and leaves of Melodinus cochinchinensis resulted in the isolation and identification of a new monoterpenoid indole alkaloid, melodicochine A (1), together with seven known monoterpenoid indole alkaloids (2-8). The chemical structure of 1 was elucidated on the basis of extensive spectral data analyses and the known compounds were identified by comparing their experimental spectral data with the reported data in the literature. All isolated indole alkaloids were evaluated for their neuroprotective effects against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells in vitro. Monoterpenoid indole alkaloids 1-8 exhibited notable neuroprotective effects with EC₅₀ values in range of 0.72 ± 0.06 to 17.89 ± 0.16 μM.

Limonoids from the Fresh Young Leaves and Buds of Toona sinensis and Their Potential Neuroprotective Effects

Toona sinensis, popularly known as Chinese toon or Chinese mahogany, is a perennial deciduous arbor belonging to the genus Toona in the Meliaceae family, which is widely distributed and cultivated in eastern and southeastern Asia. Its fresh young leaves and buds have been consumed as a very popular nutritious vegetable in China and confirmed to display a wide variety of biological activities. To investigate the chemical constituents and their potential health benefits from the fresh young leaves and buds of T. sinensis, a phytochemical study on its fresh young leaves and buds was therefore undertaken. In our current investigation, 16 limonoids (1-16), including four new limonoids, toonasinenoids A-D (1-4), and a new naturally occurring limonoid, toonasinenoid E (5), were isolated and characterized from the fresh young leaves and buds of T. sinensis. The chemical structures and absolute configurations of limonoids 1-5 were elucidated by comprehensive spectroscopic data analyses. All known limonoids (6-16) were identified via comparing their experimental spectral data containing mass spectrometry data, ¹H and ¹³C nuclear magnetic resonance data, and optical rotation values to the data reported in the literature. All known limonoids (6-16) were isolated from T. sinensis for the first time. Furthermore, the neuroprotective effects of all isolated limonoids 1-16 against 6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y cells were assessed in vitro. Limonoids 1-16 exhibited notable neuroprotective activities, with EC₅₀ values in the range from 0.27 ± 0.03 to 17.28 ± 0.16 μM. These results suggest that regular consumption of the fresh young leaves and buds of T. sinensis might prevent the occurrence and development of Parkinson's disease (PD). Moreover, the isolation and characterization of these limonoids that exhibit notable neuroprotective activities from the fresh young leaves and buds of T. sinensis could be very significant for researching and developing new neuroprotective drugs used for the prevention and treatment of PD.

High fat diet-induced obesity causes a reduction in brain tyrosine hydroxylase levels and non-motor features in rats through metabolic dysfunction, neuroinflammation and oxidative stress

Obesity is a health problem that has been associated with neuroinflammation, decreased cognitive functions and development of neurodegenerative diseases. Parkinson's disease (PD) is a chronic neurodegenerative condition characterized by motor and non-motor abnormalities, increased brain inflammation, α-synuclein protein aggregation and dopaminergic neuron loss that is associated with decreased levels of tyrosine hydroxylase (TH) in the brain. Diet-induced obesity is a global epidemic and its role as a risk factor for PD is not clear. Herein, we showed that 25 weeks on a high-fat diet (HFD) promotes significant alterations in the nigrostriatal axis of Wistar rats. Obesity induced by HFD exposure caused a reduction in TH levels and increased TH phosphorylation at serine 40 in the ventral tegmental area. These effects were associated with insulin resistance, increased tumor necrosis factor-α levels, oxidative stress, astrogliosis and microglia activation. No difference was detected in the levels of α-synuclein. Obesity also induced impairment of locomotor activity, total mobility and anxiety-related behaviors that were identified in the open-field and light/dark tasks. There were no changes in motor coordination or memory. Together, these data suggest that the reduction of TH levels in the nigrostriatal axis occurs through an α-synuclein-independent pathway and can be attributed to brain inflammation, oxidative/nitrosative stress and metabolic disorders induced by obesity.

Albumin promotes proliferation of G1 arrested serum starved hepatocellular carcinoma cells

Albumin is the most abundant plasma protein and functions as a transport molecule that continuously interacts with various cell types. Because of these properties, albumin has been exploited by the pharmaceutical industry to improve drug delivery into target cells. The immediate effects of albumin on cells, however, require further understanding. The cell interacting properties and pharmaceutical applications of albumin incentivises continual research into the immediate effects of albumin on cells. The HepG2/C3A hepatocellular carcinoma cell line is used as a model for studying cancer pathology as well as liver biosynthesis and cellular responses to drugs. Here we investigated the direct effect of purified albumin on HepG2/C3A cell proliferation in the absence of serum, growth factors and other serum originating albumin bound molecules. We observed that the reduced cell counts in serum starved HepG2/C3A cultures were increased by the inclusion of albumin. Cell cycle analysis demonstrated that the percentage of cells in G1 phase during serum starvation was reduced from 86.4 ± 2.3% to 78.3 ± 3.2% by the inclusion of albumin whereas the percentage of cells in S phase was increased from 6.5 ± 1.5% to 14.3 ± 3.6%. A significant reduction in the cell cycle inhibitor protein, P21, accompanied the changes in the proportions of cell cycle phases upon treatment with albumin. We have also observed that the levels of dead cells determined by DNA fragmentation and membrane permeabilization caused by serum starvation (TUNEL: 16.6 ± 7.2%, ethidium bromide: 13.8 ± 4.8%) were not significantly altered by the inclusion of albumin (11.6 ± 10.2%, ethidium bromide: 16.9 ± 8.9%). Therefore, the increase in cell number was mainly caused by albumin promoting proliferation rather than protection against cell death. These primary findings demonstrate that albumin has immediate effects on HepG2/C3A hepatocellular carcinoma cells. These effects should be taken into consideration when studying the effects of albumin bound drugs or pathological ligands bound to albumin on HepG2/C3A cells.

7,8,4'-Trihydroxyisoflavone, a Metabolized Product of Daidzein, Attenuates 6-Hydroxydopamine-Induced Neurotoxicity in SH-SY5Y Cells

Daidzein isolated from soybean (Glycine max) has been widely studied for its antioxidant and anti-inflammatory activities. However, the protective effects of 7,8,4'-trihydroxyisoflavone (THIF), a major metabolite of daidzein, on 6-hydroxydopamine (OHDA)-induced neurotoxicity are not well understood. In the current study, 7,8,4'-THIF significantly inhibited neuronal cell death and lactate dehydrogenase (LDH) release induced by 6-OHDA in SH-SY5Y cells, which were used as an in vitro model of Parkinson' disease (PD). Moreover, pretreatment with 7,8,4'-THIF significantly increased the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) and decreased malondialdehyde (MDA) activity in 6-OHDA-induced SH-SY5Y cells. In addition, 7,8,4'-THIF significantly recovered 6-OHDA-induced cleaved caspase-3, cleaved caspase-9, cleaved poly-ADP-ribose polymerase (PARP), increased Bax, and decreased Bcl-2 levels. Additionally, 7,8,4'-THIF significantly restored the expression levels of phosphorylated c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase 1/2 (ERK 1/2), phosphatidylinositol 3-kinases (PI3K)/Akt, and glycogen synthase kinase-3 beta (GSK-3β) in 6-OHDA-induced SH-SY5Y cells. Further, 7,8,4'-THIF significantly increased the reduced tyrosine hydroxylase (TH) level induced by 6-OHDA in SH-SY5Y cells. Collectively, these results suggest that 7,8,4'-THIF protects against 6-OHDA-induced neuronal cell death in cellular PD models. Also, these effects are mediated partly by inhibiting activation of the MAPK and PI3K/Akt/GSK-3β pathways.

Carbazole Alkaloids with Potential Neuroprotective Activities from the Fruits of Clausena lansium

Clausena lansium, also known as wampee, is a species of strongly scented evergreen trees belonging to the genus Clausena (Rutaceae), which is native to southern China. Its ripe fruits have been consumed as a very popular fruit and reported to possess a range of biological activities. To study the potential health-promoting constituents from the fruits of C. lansium, a chemical investigation on its fruits was thus carried out. In this study, 16 carbazole alkaloids (1-16), including six new carbazole alkaloids, clausenalansines A-F (1-6), were separated from the fruits of C. lansium. The molecular structures of these isolated new carbazole alkaloids (1-6) were ambiguously established on the basis of comprehensive spectroscopic methods. The known analogues (7-16) were determined via comparing their experimental data with those described in the literature, which were separated from C. lansium for the first time. All these isolated alkaloids were tested in vitro for their neuroprotective effects against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells. Carbazole alkaloids 1-16 displayed remarkable neuroprotective effects possessing the EC₅₀ values ranging from 0.36 ± 0.02 to 10.69 ± 0.15 μM. These findings indicate that regular consumption of the fruits of C. lansium may help people prevent the occurrence of Parkinson's disease. In addition, the separation and identification of these carbazole alkaloids possessing remarkable neuroprotective effects from the fruits of C. lansium could be extremely important to the discovery of new agents for the prevention and treatment of Parkinson's disease.

Dimerumic Acid and Deferricoprogen Activate Ak Mouse Strain Thymoma/Heme Oxygenase-1 Pathways and Prevent Apoptotic Cell Death in 6-Hydroxydopamine-Induced SH-SY5Y Cells

Parkinson's disease (PD) is a neurodegenerative disorder, which can be modeled using the neurotoxin 6-hydroxydopamine (6-OHDA) to generate oxidative stress. Here, we studied the effects of the antioxidants deferricoprogen (DFC) and dimerumic acid (DMA), produced by rice fermented with Monascus purpureus NTU 568, on 6-OHDA-induced apoptosis in SH-SY5Y cells and their potential protective mechanisms. DMA and DFC inhibited 6-OHDA-induced apoptosis and cellular reactive oxygen species (ROS) in SH-SY5Y human neuroblastoma cells. Molecular analysis demonstrated associated upregulation of the Ak mouse strain thymoma (Akt), heme oxygenase-1 (HO-1), and signal-regulated kinase (ERK) pathways along with inhibited phosphorylation of c-Jun N-terminal kinase (JNK) and p38 pathways and altered homodimeric glycoprotein, N-methyl-d-aspartate (NMDA) receptor, and immunoglobulin Fc receptor gene expression. These results suggested that the neuroprotection elicited by DMA and DFC against 6-OHDA-induced neurotoxicity was associated with the Akt, MAPK, and HO-1 pathways via regulating the gene expression of NMDA receptor, homodimeric glycoprotein, and immunoglobulin Fc receptor.

Assessment of Protective Role of Multifunctional Dopamine Agonist D-512 Against Oxidative Stress Produced by Depletion of Glutathione in PC12 Cells: Implication in Neuroprotective Therapy for Parkinson's Disease

Oxidative stress has been strongly implicated in the progression of Parkinson's disease (PD). Depletion of cytoplasmic glutathione levels is one of the indications of oxidative stress, which occur in the substantia nigra of PD patients at an early stage of the disease process. It has been shown that glutathione depletion causes the inhibition of mitochondrial complex I, thus affecting mitochondrial function leading to oxidative stress via production of reactive oxygen species. Studies were carried out to investigate the role of D-512, a potent multifunctional neuroprotective D2/D3 receptor agonist, in protecting dopaminergic PC12 cells treated with buthionine sulfoximine (BSO), an inhibitor of key enzyme in glutathione synthesis and 6-hydroxydopamine (6-OHDA), a widely used neurotoxin. D-512 was able to restore level of glutathione against BSO/6-OHDA-mediated glutathione depletion. D-512 also showed significant neuroprotection in PC12 cells against toxicity induced by combined treatment of BSO and 6-OHDA. Furthermore, D-512 was able to restore both phospho-extracellular signal-regulated kinase and phospho-Jun N-terminal kinase levels upon treatment with 6-OHDA providing an evidence on the possible mechanism of action for neuroprotection by modulating mitogen-activated protein kinases. We have further demonstrated the neuroprotective effects of D-512 against oxidative insult produced by BSO and 6-OHDA in PC12 cells.

p38 MAPK and PI3K/AKT Signalling Cascades inParkinson's Disease

Parkinson's disease (PD) is a chronic neurodegenerative condition which has the second largest incidence rate among all other neurodegenerative disorders barring Alzheimer's disease (AD). Currently there is no cure and researchers continue to probe the therapeutic prospect in cell cultures and animal models of PD. Out of the several factors contributing to PD prognosis, the role of p38 MAPK (Mitogen activated protein-kinase) and PI3K/AKT signalling module in PD brains is crucial because the impaired balance between the pro- apoptotic and anti-apoptotic pathways trigger unwanted phenotypes such as microglia activation, neuroinflammation, oxidative stress and apoptosis. These factors continue challenging the brain homeostasis in initial stages thereby essentially assisting the dopaminergic (DA) neurons towards progressive degeneration in PD. Neurotherapeutics against PD shall then be targeted against the misregulated accomplices of the p38 and PI3K/AKT cascades. In this review, we have outlined many such established mechanisms involving the p38 MAPK and PI3K/AKT pathways which can offer therapeutic windows for the rectification of aberrant DA neuronal dynamics in PD brains.

Combination of mild hypothermia with neuroprotectants has greater neuroprotective effects during oxygen-glucose deprivation and reoxygenation-mediated neuronal injury

Co-treatment of neuroprotective reagents may improve the therapeutic efficacy of hypothermia in protecting neurons during ischemic stroke. This study aimed to find promising drugs that enhance the neuroprotective effect of mild hypothermia (MH). 26 candidate drugs were selected based on different targets. Primary cultured cortical neurons were exposed to oxygen-glucose deprivation and reoxygenation (OGD/R) to induce neuronal damage, followed by either single treatment (a drug or MH) or a combination of a drug and MH. Results showed that, compared with single treatment, combination of MH with brain derived neurotrophic factor, glibenclamide, dizocilpine, human urinary kallidinogenase or neuroglobin displayed higher proportion of neuronal cell viability. The latter three drugs also caused less apoptosis rate in combined treatment. Furthermore, co-treatment of those three drugs and MH decreased the level of reactive oxygen species (ROS) and intracellular calcium accumulation, as well as stabilized mitochondrial membrane potential (MMP), indicating the combined neuroprotective effects are probably via inhibiting mitochondrial apoptosis pathway. Taken together, the study suggests that combined treatment with hypothermia and certain neuroprotective reagents provide a better protection against OGD/R-induced neuronal injury.

Erythropoietin improves neurobehavior by reducing dopaminergic neuron loss in a 6‑hydroxydopamine‑induced rat model

The purpose of this study was to determine the effectiveness of the systemic administration of high dose erythropoietin (EPO) in a 6-hydroxydopamine (6-OHDA)- induced rat model. Rats were divided into 7 groups. Groups 1–4 were administered daily EPO doses of 0; 2,500; 5,000 and 10,000 U/kg via intraperitoneal injection (i.p.) for 5 days. The EPO concentration in cerebrospinal fluid (CSF) was determined by enzyme-linked immunosorbent assay (ELISA) and western blot analysis. The dose of 10,000 U/kg was then selected for subsequent experiments. In group 5, rats received saline via medial forebrain bundle (MFB). In group 6, rats received 6-OHDA via MFB. In group 7, an EPO concentration of 10,000 U/kg was constantly administered i.p. for 5 days to rats prior to 6-OHDA injection via MFB. Behavioral analysis was performed for groups 5–7 by rat rotation tests. The number of tyrosine hydroxylase (TH)-immunopositive cells in the substantia nigra (SN) was measured by immunocytochemistry. The activation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinases (MAPKs) and caspase-3 signaling in rats were analyzed using western blotting. The results showed that there was a significant increase in EPO levels in the CSF in 10,000 U/kg group compared with the 2,500 and 5,000 U/kg groups (P<0.01). Significantly fewer rotational counts were obtained in rats that were pretreated with EPO compared with saline-pretreated 6-OHDA-lesioned rats (P<0.001). The dopaminergic neurons in the 6-OHDA-lesioned SN were also increased in the EPO-pretreated rats when compared with control rats (P<0.01). Western blot analysis revealed that EPO inhibited the 6-OHDA-induced activation of JNK, ERK, p38 MAPK and caspase-3 signaling in the rat model. In conclusion, systemic administration of a high dose of EPO exerted neuroprotective effects in reversing behavioral deficits associated with Parkinson’s disease and prevented loss of the dopaminergic neurons through the MAPK pathway.

Luteolin modulates 6-hydroxydopamine-induced transcriptional changes of stress response pathways in PC12 cells

The neurotoxin 6-hydroxydopamine (6-OHDA), which causes transcriptional changes associated with oxidative and proteotoxic stress, has been widely used to generate an experimental model of Parkinson's disease. The food-derived compound luteolin has multi-target actions including antioxidant, anti-inflammatory and neurotrophic activities. The aim of this study is to investigate how luteolin affects 6-OHDA-mediated stress response pathways. The results showed that when PC12 cells were pre-treated with luteolin (20 µM) 30 min prior to 6-OHDA (100 µM) exposure, 6-OHDA-induced ROS overproduction, cytotoxicity, caspase-3 activation, and mRNA expression of BIM, TRB3 and GADD34 were significantly attenuated. Moreover, 6-OHDA-mediated cell cycle arrest and transcription of p53 target genes, p21, GADD45α and PUMA, were reduced by luteolin. Luteolin also significantly down-regulated 6-OHDA-mediated unfolded protein response (UPR), leading to decreases in phospho-eIF2α, ATF4, GRP78 and CHOP. In addition, luteolin attenuated 6-OHDA-induced Nrf2-mediated HO-1 and GCLC. Taken together, these results suggest that diminishing intracellular ROS formation and down-regulation of p53, UPR and Nrf2-ARE pathways may be involved in the neuroprotective effect of luteolin.

Neuron-derived IgG protects dopaminergic neurons from insult by 6-OHDA and activates microglia through the FcγR I and TLR4 pathways

Oxidative and immune attacks from the environment or microglia have been implicated in the loss of dopaminergic neurons of Parkinson's disease. The role of IgG which is an important immunologic molecule in the process of Parkinson's disease has been unclear. Evidence suggests that IgG can be produced by neurons in addition to its traditionally recognized source B lymphocytes, but its function in neurons is poorly understood. In this study, extensive expression of neuron-derived IgG was demonstrated in dopaminergic neurons of human and rat mesencephalon. With an in vitro Parkinson's disease model, we found that neuron-derived IgG can improve the survival and reduce apoptosis of dopaminergic neurons induced by 6-hydroxydopamine toxicity, and also depress the release of NO from microglia triggered by 6-hydroxydopamine. Expression of TNF-α and IL-10 in microglia was elevated to protective levels by neuron-derived IgG at a physiologic level via the FcγR I and TLR4 pathways and microglial activation could be attenuated by IgG blocking. All these data suggested that neuron-derived IgG may exert a self-protective function by activating microglia properly, and IgG may be involved in maintaining immunity homeostasis in the central nervous system and serve as an active factor under pathological conditions such as Parkinson's disease.

Functional analysis of a survivin-like gene in Bombyx mori

The survivin (svv) gene is a newly discovered member of the inhibitors of apoptosis gene family. In recent years, svv has been confirmed to have an anti-apoptosis function and to play a critical role in cell division. We identified a survivin-like gene in the silkworm, Bombyx mori (Bm-svv). In this study, to gain insight into its function, a baculovirus expression system was used to express the Bm-svv gene in insect cell lines. The recombinant viruses were then used as a vector to transform insect cells, and cell activity was determined using the Cell Counting Kit-8 (CCK-8), which is usually employed for detecting mammalian cell number. The results indicated that the Bm-svv gene plays a role in the cell growth arrest or apoptosis induced by viruses. Furthermore, the CCK-8 kit is effective in determining the activity of insect cells.