Progress in Pharmacological Sciences in China.

Pharmacology is the science that investigates the interactions between organisms and drugs and their mechanisms. Pharmacology plays a translational role in modern medicine, bridging basic research and the clinic. With its economy booming, China has invested an enormous amount of financial and human resources in pharmacological research in the recent decade. As a result, major breakthroughs have been achieved in both basic and clinical research, with the discovery of many potential drug targets and biomarkers that has made a sizable contribution to the overall advancement of pharmacological sciences. In this article, we review recent research efforts and representative scientific achievements and discuss future challenges and directions for the pharmacological sciences in China.

Dual pathways mediate ß-amyloid stimulated glutathione release from astrocytes.

Oxidative stress plays an important role in the progression of Alzheimer's disease (AD) and other neurodegenerative conditions. Glutathione (GSH), the major antioxidant in the central nervous system, is primarily synthesized and released by astrocytes. We determined if ß-amyloid (Aß42), crucially involved in Alzheimer's disease, affected GSH release. Monomeric Aß (mAß) stimulated GSH release from cultured cortical astrocytes more effectively than oligomeric Aß (oAß) or fibrillary Aß (fAß). Monomeric Aß increased the expression of the transporter ABCC1 (also referred to as MRP1) that is the main pathway for GSH release. GSH release from astrocytes, with or without mAß stimulation, was reduced by pharmacological inhibition of ABCC1. Astrocytes robustly express connexin proteins, especially connexin43 (Cx43), and mAß also stimulated Cx43 hemichannel-mediated glutamate and GSH release. Aß-stimulation facilitated hemichannel opening in the presence of normal extracellular calcium by reducing astrocyte cholesterol level. Aß treatment did not alter the intracellular concentration of reduced or oxidized glutathione. Using a mouse model of AD with early onset Aß deposition (5xFAD), we found that cortical ABCC1 was significantly increased in temporal register with the surge of Aß levels in these mice. ABCC1 levels remained elevated from 1.5 to 3.5 months of age in 5xFAD mice, before plunging to subcontrol levels when amyloid plaques appeared. Similarly, in cultured astrocytes, prolonged incubation with aggregated Aß, but not mAß, reduced induction of ABCC1 expression. These results support the hypothesis that in the early stage of AD pathogenesis, less aggregated Aß increases GSH release from astrocytes (via ABCC1 transporters and Cx43 hemichannels) providing temporary protection from oxidative stress which promotes AD development.

Tripchlorolide improves cognitive deficits by reducing amyloid ß and upregulating synapse-related proteins in a transgenic model of Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by early impairments in memory and progressive neurodegeneration. Disruption of synaptic plasticity processes that underlie learning and memory contribute partly to this pathophysiology. Tripchlorolide (T4 ), an extract from a traditional Chinese herbal Tripterygium wilfordii Hook F, has been shown to be neuroprotective in animal models of Parkinson's disease and to improve cognitive deficits in senescence-accelerated mouse P8. In this study, we investigated the effect of T4 on cognitive decline and synaptic plasticity in five times familial AD (5XFAD) mice co-expressing mutated amyloid precursor protein and presenilin-1. Five-month-old 5XFAD mice and wild type littermates were intraperitoneally injected with T4 , 5 µg/kg or 25 µg/kg, every other day for 60 days. T4 treatment significantly improved spatial learning and memory, alleviated synaptic ultrastructure degradation, up-regulated expression of synapse-related proteins, including synaptophysin, post-synaptic density-95, N-methyl-D-aspartate receptor subunit 1, phosphorylation of calcium/calmodulin dependent protein kinase II α, and phosphorylation of cyclic AMP-response element binding protein, and promoted activation of the phophoinositide-3-kinase-Akt-mammalian target of rapamycin signaling pathway in 5XFAD mice. Accumulation of amyloid ß (Aß) may contribute to synapse dysfunction and memory impairment in AD. We found that T4 treatment significantly reduced cerebral Aß deposits and lowered Aß levels in brain homogenates. These effects coincided with a reduction in cleavage of ß-carboxyl-terminal amyloid precursor protein (APP) fragment, levels of soluble APPß, and protein expression of ß-site APP cleaving enzyme 1. Taken together, our findings identify T4 as a potent negative regulator of brain Aß levels and show that it significantly ameliorates synaptic degeneration and cognitive deficits in a mouse model of AD.

Comparison of Therapeutic Effects Between Conventional 2D Laparoscopy and 3D Laparoscopy in the Treatment of Colorectal Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: This study aimed to evaluate the effectiveness and safety of 2D laparoscopy vs 3D laparoscopy for the treatment of colorectal cancer. METHODS: A literature search was conducted through PubMed, Web of Science, and Embase from their inception to January 2024. Studies investigating different outcomes of colorectal surgery were included. Results are presented as odds ratios (ORs) or mean differences (MDs) with 95% confidence intervals (CIs). The protocol for this review has been registered on PROSPERO (CRD42024504902). RESULTS: A total of 10 publications were retrieved in this article. The 3D group is associated with a significant improvement in intraoperative blood loss (MD = -8.04, 95% CI = -14.18 to -1.89, P = 0.01, I2 = 55%), operative time (MD = -17.33, 95% CI = -29.15 to -5.51, P = 0.004, I2 = 90%), and postoperative hospital stay (MD = -0.23, 95% CI = -0.43 to -0.04, P = 0.02, I2 = 48%) compared to that of patients treated in the 2D group, particularly for rectal cancer patients above three results (MD = -10.36, 95% CI = -15.00 to -5.73, P < 0.001, I2 = 0%), (MD = -18.85, 95% CI = -34.88 to -2.82, P = 0.02, I2 = 57%), and (MD = -0.93, 95% CI = -1.53 to -0.34, P = 0.002, I2 = 0%), respectively. There was no significant statistical difference in the time of pass flatus (MD = -0.14, 95% CI = -0.49 to 0.21, P = 0.44, I2 = 79%) and the number of dissected lymph nodes (MD = 0.36, 95% CI = -0.49 to 1.21, P = 0.41, I2 = 45%), but the 3D group had an earlier postoperative pass flatus for rectal cancer patients (MD = -0.46, 95% CI = -0.66 to -0.27, P<0.001, I2 = 0%) and the more number of dissected lymph nodes for colon cancer patients (MD = 1.54, 95% CI = 0.05 to 3.03, P = 0.04, I2 = 69%) than the 2D group. There was no significant difference in postoperative overall complication (OR = 0.94, 95% CI = 0.67 to 1.31, P = 0.71, I2 = 0%) and anastomotic leakage (OR = 0.93, 95% CI = 0.48 to 1.80, P = 0.83, I2 = 0%) in the two groups, regardless of rectal cancer and colon surgery patients. CONCLUSION: This meta-analysis demonstrates that 3D laparoscopy could reduce the amount of blood loss, accelerate postoperative pass flatus, and shorten the operation time and postoperative hospital stay over 2D for radical rectal cancer surgery, without obvious advantage for radical colon cancer surgery. Moreover, 3D laparoscopy increases the number of dissected lymph nodes for radical colon cancer surgery but may not be observed in rectal cancer surgery.

Astaxanthin suppresses MPP(+)-induced oxidative damage in PC12 cells through a Sp1/NR1 signaling pathway.

OBJECTIVE: To investigate astaxanthin (ATX) neuroprotection, and its mechanism, on a 1-methyl-4-phenyl-pyridine ion (MPP+)-induced cell model of Parkinson's disease. METHODS: Mature, differentiated PC12 cells treated with MPP+ were used as an in vitro cell model. The MTT assay was used to investigate cell viability after ATX treatment, and western blot analysis was used to observe Sp1 (activated transcription factor 1) and NR1 (NMDA receptor subunit 1) protein expression, real-time PCR was used to monitor Sp1 and NR1 mRNA, and cell immunofluorescence was used to determine the location of Sp1 and NR1 protein and the nuclear translocation of Sp1. RESULTS: PC12 cell viability was significantly reduced by MPP+ treatment. The expression of Sp1 and NR1 mRNA and protein were increased compared with the control (p < 0.01). Following co-treatment with ATX and MPP+, cell viability was significantly increased, and Sp1 and NR1 mRNA and protein were decreased, compared with the MPP+ groups (p < 0.01). In addition, mithracycin A protected PC12 cells from oxidative stress caused by MPP+ by specifically inhibiting the expression of Sp1. Moreover, cell immunofluorescence revealed that ATX could suppress Sp1 nuclear transfer. CONCLUSION: ATX inhibited oxidative stress induced by MPP+ in PC12 cells, via the SP1/NR1 signaling pathway.

APOE genotype alters glial activation and loss of synaptic markers in mice.

The ε4 allele of the Apolipoprotein E (APOE) gene is the strongest genetic risk factor for late-onset Alzheimer's disease (AD), and affects clinical outcomes of chronic and acute brain damages. The mechanisms by which apoE affect diverse diseases and disorders may involve modulation of the glial response to various types of brain damage. We examined glial activation in a mouse model where each of the human APOE alleles are expressed under the endogenous mouse APOE promoter, as well as in APOE knock-out mice. APOE4 mice displayed increased glial activation in response to intracerebroventricular lipopolysaccharide (LPS) compared to APOE2 and APOE3 mice by several measures. There were higher levels of microglia/macrophage, astrocytes, and invading T-cells after LPS injection in APOE4 mice. APOE4 mice also displayed greater and more prolonged increases of cytokines (IL-1ß, IL-6, TNF-α) than APOE2 and APOE3 mice. We found that APOE4 mice had greater synaptic protein loss after LPS injection, as measured by three markers: PSD-95, drebin, and synaptophysin. In all assays, APOE knock-out mice responded similar to APOE4 mice, suggesting that the apoE4 protein may lack anti-inflammatory characteristics of apoE2 and apoE3. Together, these findings demonstrate that APOE4 predisposes to inflammation, which could contribute to its association with Alzheimer's disease and other disorders.

Astaxanthin protects against MPP(+)-induced oxidative stress in PC12 cells via the HO-1/NOX2 axis.

BACKGROUND: Although the etiology of PD remains unclear, increasing evidence has shown that oxidative stress plays an important role in its pathogenesis and that of other neurodegenerative disorders. NOX2, a cytochrome subunit of NOX, transports electrons across the plasma membrane to generate ROS, leading to physiological and pathological processes. Heme oxygenase-1 (HO-1) can be rapidly induced by oxidative stress and other noxious stimuli in the brain or other tissues. Astaxanthin (ATX), a carotenoid with antioxidant properties, is 100-1000 times more effective than vitamin E. The present study investigated the neuroprotective effects of ATX on MPP(+)-induced oxidative stress in PC12 cells. RESULTS: MPP(+) significantly decreased MTT levels in a concentration-dependent manner. Hemin, SnPPIX and ATX didn't exhibit any cytotoxic effects on PC12 cells. Pretreatment with ATX (5, 10, 20 µM), caused intracellular ROS production in the MPP(+) group to decrease by 13.06%, 22.13%, and 27.86%, respectively. MPP(+) increased NOX2, NRF2 and HO-1 protein expression compared with control (p < 0.05). Co-treatment with hemin or ATX suppressed NOX2 expression (p < 0.01), and greatly increased NRF2 and HO-1 expression (p < 0.01). MPP(+) treatment up-regulated both NOX2 (p < 0.01) and HO-1 (p < 0.01) mRNA levels. Co-treatment with hemin or ATX significantly increased HO-1 mRNA levels (p < 0.01), and decreased NOX2 mRNA levels (p < 0.01). MPP(+) increased NOX2 and HO-1 expression with considerable fluorescence extending out from the perinuclear region toward the periphery; this was attenuated by DPI. Co-treatment with hemin or ATX significantly up-regulated HO-1 expression and decreased NOX2 expression with considerable fluorescence intensity (stronger than the control and MPP(+) groups). CONCLUSIONS: ATX suppresses MPP(+)-induced oxidative stress in PC12 cells via the HO-1/NOX2 axis. ATX should be strongly considered as a potential neuroprotectant and adjuvant therapy for patients with Parkinson's disease.

Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels in cultured rat hippocampal neurons.

AIM: To investigate the effect of ginsenoside Rb1 on voltage-gated calcium currents in cultured rat hippocampal neurons and the modulatory mechanism. METHODS: Cultured hippocampal neurons were prepared from Sprague Dawley rat embryos. Whole-cell configuration of the patch-clamp technique was used to record the voltage-gated calcium currents (VGCCs) from the hippocampal neurons,and the effect of Rb1 was examined. RESULTS: Rb1 (2-100 µmol/L) inhibited VGCCs in a concentration-dependent manner, and the current was mostly recovered upon wash-out. The specific L-type Ca(2+) channel inhibitor nifedipine (10 µmol/L) occluded Rb1-induced inhibition on VGCCs. Neither the selective N-type Ca(2+) channel blocker ω-conotoxin-GVIA (1 µmol/L), nor the selective P/Q-type Ca(2+) channel blocker ω-agatoxin IVA (30 nmol/L) diminished Rb1-sensitive VGCCs. Rb1 induced a leftward shift of the steady-state inactivation curve of I(Ca) to a negative potential without affecting its activation kinetics or reversal potential in the I-V curve. The inhibitory effect of Rb1 was neither abolished by the adenylyl cyclase activator forskolin (10 µmol/L), nor by the PKA inhibitor H-89 (10 µmol/L). CONCLUSION: Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels, without affecting the N-type or P/Q-type Ca(2+) channels in hippocampal neurons. cAMP-PKA signaling pathway is not involved in this effect.

Epigallocatechin-3-gallate suppresses 1-methyl-4-phenyl-pyridine-induced oxidative stress in PC12 cells via the SIRT1/PGC-1α signaling pathway.

BACKGROUND: Parkinson's disease is a high incidence neurodegenerative disease in elderly people, and oxidative stress plays an important role in the pathogenesis. Oxygen metabolism in the brain is high, which lacks an antioxidative protection mechanism. Recently, it has been found that polyphenols play an important role in antioxidation. (-)-epigallocatechin-3-gallate (EGCG) is an important component of tea polyphenols and its biological effects, such as strong antioxidation, scavenging of free radicals and anti-apoptosis, can pass through the blood brain barrier. The SIRT1/PGC-1α signaling pathway has not been reported in PC12 cells. Therefore, research of the protective mechanism of EGCG in PC12 cells damaged by -methyl-4-phenyl-pyridine (MMP+) may provide a new insight into protect against and treatment of Parkinson's disease. METHODS: MPP(+)-treated highly differentiated PC12 cells were used as the in vitro cell model. An MTT assay was used to investigate cell viability after EGCG treatment, a dichlorofluorescin diacetate assay was used to measure reactive oxygen species (ROS) production, western blot analysis was used to observe PGC-1α and SIRT1 protein expression, and real-time PCR to observe PGC-1α, SOD1 and GPX1 mRNA expression. RESULTS: PC12 cell viability was significantly reduced after MPP(+) treatment by 11.46% compared with that of the control (P < 0.05). However, cell viability was unchanged by 10 µmol/L EGCG treatment. In co-treatments with EGCG and MPP(+), cell viability was significantly increased by 12.92% (P < 0.05) and MPP(+)-induced ROS production was markedly decreased. PGC-1α mRNA expression was obviously upregulated by 21.51% (P < 0.05), and SOD1 and GPX1 mRNA expression was slightly increased by 12.94% and 15.63% (P > 0.05), respectively, by treatment with EGCG and then MPP(+) for 12 h. The mRNA expression of PGC-1α, SOD1 and GPX1 was increased by 25.17%, 40% and 146% (all P < 0.05), respectively, by treatment with EGCG and then MPP(+) for 24 h. Such effects were not observed with MPP(+) treatment alone. CONCLUSION: The SIRT1/PGC-1α pathway is one of the mechanisms of EGCG suppression of MPP(+)-induced injury of PC12 cells.

[Mechanism of ginsenoside Rg1 regulating the activity of ß secretase in N2a/APP695 cells].

OBJECTIVE: To explore whether or not ginsenoside Rg1 can modify the metabolism of amyloid precursor protein (APP) and the generation of amyloid beta (Aß) by nuclear factor-kappa B (NF-κB). METHODS: N2a/APP695 cells, a mutated APP-overexpressing neuronal cell line, was used to mimic the APP metabolism and Aß generation in vitro. The BACE1 mRNA and protein levels were detected by RT-PCR (reverse transcription-polymerase chain reaction) and Western blot respectively. Then the expression levels and subcellular localization of NF-κB were detected by Western blot and confocal laser scanning microscope respectively. RESULTS: The treatment of ginsenoside Rg1 at a dose of 2.5 µmol/L decreased the levels of Aß1-40 and Aß1-42 (13.3 ± 4.3) ng/ml vs (12.0 ± 5.4) ng/ml in N2a/APP695 cells, decreased the protein level of BACE1 (BACE1/ß-actin 0.26 ± 0.05), increased the protein level of NF-κB p65 (p-p65/p65 0.93 ± 0.02) and resulted in the translocation of NF-κB from cytoplasm to nucleus. Quinazoline inhibited the activation of NF-κB with a reduction of p-p65 and p-p65/p65 in N2a/APP695 cells and increased the BACE1 protein level. And the treatment of ginsenoside Rg1 showed similar changes in N2a/APP695 cells when compared with the treatment of quinazoline alone. CONCLUSION: Ginsenoside Rg1 may modify the metabolism of APP by enhancing the nuclear binding of NF-κB to BACE1 promoter and inhibiting the transcription and translation of BACE1.

[Influence of ilexonin A on the expression of bFGF, GAP-43 and neurogenesis after cerebral ischemia-reperfusion in rats].

This study is to observe the effect of ilexonin A (IA) on the expression of basic fibroblast growth factor (bFGF) and growth associated protein-43 (GAP-43), and neurogenesis after cerebral ischemia-reperfusion in rats and explore its possible mechanism of protecting neuronal injury. Models of middle cerebral artery occlusion (MCAO) were established in SD rats. Before and after two hours ischemia-reperfusion, IA (20 and 40 mg x kg(-1)) was injected immediately and on 3, 7, 14, and 28 d once a day. The neurological severity was evaluated by neurological severity scores (NSS); neuronal injury in the boundary zone of the infarction area was evaluated by TUNEL and Niss1 staining. The expressions of bFGF and GAP-43 and neurogenesis were evaluated by Western blotting and 5-bromodeoxyuridine (Brdu) fluorescence staining, respectively. After treatment with IA, the NSS of treatment groups were lower than that of the models (3 and 7 d). The number of TUNEL positive neurons decreased and Nissl positive neurons increased at the same time (3 d). The expressions of bFGF and GAP-43 increased significantly in the boundary zone of the infarction area when compared to model group. Moreover, IA markedly enhanced the neurogenesis in the brain after ischemia-reperfusion, which revealed an increase of Brdu/NeuN positive cells in the boundary zone of the infarction area. The possible mechanism of protecting neuronal injury of IA may be related to inhibition on neuronal apoptosis, upregulation of bFGF and GAP-43, and neurogenesis in boundary zone of infarction after cerebral ischemia-reperfusion.

[Involvement of Wnt/beta-catenin signaling in tripchlorolide protecting against oligomeric beta-amyloid-(1-42)-induced neuronal apoptosis].

This study is to explore whether the Wnt/beta-catenin signaling pathway is involved in the process of tripchlorolide (T4) protecting against oligomeric Abeta(1-42)-induced neuronal apoptosis. Primary cultured cortical neurons were used for the experiments on day 6 or 7. The oligomeric Abeta(1-42) (5 micromol x L(-1) for 24 h) was applied to induce neuronal apoptosis. Prior to treatment with Abeta(1-42) for 24 h, the cultured neurons were pre-incubated with T4 (2.5, 10, and 40 nmol x L(-1)), Wnt3a (Wnt signaling agonists) and Dkk1 (inhibitors) for indicated time. Then the cell viability, neuronal apoptosis, and protein levels of Wnt, glycogen synthase kinase 3beta (GSK3beta), beta-catenin and phospho-beta-catenin were measured by MTT assay, TUNEL staining and Western blotting, respectively. The result demonstrated that oligomeric Abeta(1-42) induced apoptotic neuronal cell death in a time- and dose-dependent manner. Pretreatment with T4 significantly increased the neuronal cell survival and attenuated neuronal apoptosis. Moreover, oligomeric Abeta(1-42)-induced phosphorylation of beta-catenin and GSK3beta was markedly inhibited by T4. Additionally, T4 stabilized cytoplasmic beta-catenin. These results indicate that tripchlorolide protects against the neurotoxicity of Abeta by regulating Wnt/beta-catenin signaling pathway. This may provide insight into the clinical application of tripchlorolide to Alzheimer's disease.

Tripchlorolide protects neuronal cells from microglia-mediated beta-amyloid neurotoxicity through inhibiting NF-kappaB and JNK signaling.

Recent research has focused on soluble oligomeric assemblies of beta-amyloid peptides (Abeta) as the proximate cause of neuroinflammation, synaptic loss, and the eventual dementia associated with Alzheimer's disease (AD). In this study, tripchlorolide (T4), an extract of Tripterygium wilfordii Hook. F (TWHF), was studied as a novel agent to suppress neuroinflammatory process in microglial cells and to protect neuronal cells against microglia-mediated oligomeric Abeta toxicity. T4 significantly attenuated oligomeric Abeta(1-42)-induced release of inflammatory productions such as tumor necrosis factor-alpha, interleukin-1beta, nitric oxide (NO), and prostaglandin E2. It also downregulated the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in microglial cells. Further molecular mechanism study demonstrated that T4 inhibited the nuclear translocation of nuclear factor-kappaB (NF-kappaB) without affecting I-kappaBalpha phosphorylation. It repressed Abeta-induced JNK phosphorylation but not ERK or p38 MAPK. The inhibition of NF-kappaB and JNK by T4 is correlated with the suppression of inflammatory mediators in Abeta-stimulated microglial cells. These results suggest that T4 protects neuronal cells by blocking inflammatory responses of microglial cells to oligomeric Abeta(1-42) and that T4 acts on the signaling of NF-kappaB and JNK, which are involved in the modulation of inflammatory response. Therefore, T4 may be an effective agent in modulating neuroinflammatory process in AD.

Ginsenoside Rg1 delays tert-butyl hydroperoxide-induced premature senescence in human WI-38 diploid fibroblast cells.

Tert-butyl hydroperoxide (t-BHP), an analog of hydroperoxide, induced characteristic changes of senescence in human diploid fibroblasts WI-38 cells. It was reported that ginsenoside Rg1, an active ingredient of ginseng, ameliorated learning deficits in aged rats. The present study was aimed to investigate whether ginsenoside Rg1 can delay the premature senescence of WI-38 cells induced by t-BHP and to explore the underlying molecular mechanisms. First, Rg1 pretreatment markedly reversed senescent morphological changes in WI-38 cells induced by t-BHP. Second, t-BHP treatment alone resulted in an increase in the protein levels of P16 and P21, and a decline in intracellular adenosine 5'-triphosphate (ATP) level and mitochondrial complex IV activity. Ginsenoside Rg1 pretreatment had significant effects of attenuating these changes. These data indicate that ginsenoside Rg1 has an anti-aging effect on t-BHP-induced premature senescence in WI-38 cells. This effect may be mediated by regulating cell cycle proteins and enhancing mitochondrial functioning.

Involvement of calpain and p25 of CDK5 pathway in ginsenoside Rb1's attenuation of beta-amyloid peptide25-35-induced tau hyperphosphorylation in cortical neurons.

Increasing evidence have shown that beta-amyloid (Abeta) induced hyperphosphorylation of tau, which eventually resulted in the disruption of microtubule (MT) integrity. Cyclin-dependent kinase 5 (CDK5) and its activator p35 are required for neurite outgrowth. The cleavage of p35 to p25, mediated by calpain and calcium, caused CDK5 dislocation and subsequently p25/CDK5-induced tau hyperphosphorylation, which disrupted the cytoskeleton and resulted in neuronal death. In the present study we investigated the effects of ginsenoside Rb1 on fibrillar Abeta(25-35)-induced tau hyperphosphorylation in primary cultured cortical neurons and also the potential involvement of Ca(2+)-calpain-CDK5 signal pathway. The present study suggests that Ca(2+), calpain, and p25 in CDK5 pathway may play important roles in Abeta(25-35)-induced tau hyperphosphorylation.

Altered glutathione homeostasis in animals prenatally exposed to lipopolysaccharide.

We previously reported that injection of bacterial lipopolysaccharide (LPS) into gravid female rats at embryonic day 10.5 resulted in a birth of offspring with fewer than normal dopamine (DA) neurons along with innate immunity dysfunction and many characteristics seen in Parkinson's disease (PD) patients. The LPS-exposed animals were also more susceptible to secondary toxin exposure as indicated by an accelerated DA neuron loss. Glutathione (GSH) is an important antioxidant in the brain. A disturbance in glutathione homeostasis has been proposed for the pathogenesis of PD. In this study, animals prenatally exposed to LPS were studied along with an acute intranigral LPS injection model for the status of glutathione homeostasis, lipid peroxidation, and related enzyme activities. Both prenatal LPS exposure and acute LPS injection produced a significant GSH reduction and increase in oxidized GSH (GSSG) and lipid peroxide (LPO) production. Activity of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme in de novo GSH synthesis, was up-regulated in acute supranigral LPS model but was reduced in the prenatal LPS model. The GCS light subunit protein expression was also down-regulated in prenatal LPS model. GSH redox recycling enzyme activities (glutathione peroxidase, GPx and glutathione reducdase, GR) and glutathione-S-transferase (GST), gamma-glutamyl transpeptidase (gamma-GT) activities were all increased in prenatal LPS model. Prenatal LPS exposure and aging synergized in GSH level and GSH-related enzyme activities except for those (GR, GST, and gamma-GT) with significant regional variations. Additionally, prenatal LPS exposure produced a reduction of DA neuron count in the substantia nigra (SN). These results suggest that prenatal LPS exposure may cause glutathione homeostasis disturbance in offspring brain and render DA neurons susceptible to the secondary neurotoxin insult.

Curcumin Ameliorates Memory Decline via Inhibiting BACE1 Expression and ß-Amyloid Pathology in 5×FAD Transgenic Mice.

Alzheimer's disease (AD) is the most common dementia and the trigger of its pathological cascade is widely believed to be the overproduction and accumulation of ß-amyloid protein (Aß) in the affected brain. However, effective AD remedies are still anxiously awaited. Recent evidence suggests that curcumin may be a potential agent for AD treatment. In this study, we used 5×FAD transgenic mice as an AD model to investigate the effects of curcumin on AD. Our results showed that curcumin administration (150 or 300 mg/kg/day, intragastrically, for 60 days) dramatically reduced Aß production by downregulating BACE1 expression, preventing synaptic degradation, and improving spatial learning and memory impairment of 5×FAD mice. These findings suggest that curcumin is a potential candidate for AD treatment.

Age-related changes in glutathione and glutathione-related enzymes in rat brain.

The most reliable and robust risk factor for some neurodegenerative diseases is aging. It has been proposed that processes of aging are associated with the generation of reactive oxygen species and a disturbance of glutathione homeostasis in the brain. Yet, aged animals have rarely been used to model the diseases that are considered to be age-related such as Parkinson's or Alzheimer's disease. This suggests that the results from these studies would be more valuable if aged animals were used. The present study was designed to provide insight into the glutathione redox state in young and aged rat siblings of both genders by studying the enzyme activities related to glutathione synthesis, cycling, and usage. The results suggested a significant age-related reduction of reduced glutathione (GSH) level in all brain regions examined, associated with an increase of GSH oxidation to glutathione disulfide (GSSG) and decrease of the GSH/GSSG ratio. These changes were accompanied by diminished gamma-glutamylcysteine synthetase activity in de novo glutathione synthesis and increased lipid peroxidation. In addition, these changes were associated with increased enzyme activities related to the GSH usage (glutathione peroxidase, gamma-glutamyl transpeptidase, and glutathione S-transferase). The results indicate that aged animals are likely more vulnerable to oxidative stress and insinuate the roles of aged animals in modeling age-related neurodegeneration diseases.