Ghrelin protects spinal cord motoneurons against chronic glutamate excitotoxicity by inhibiting microglial activation

Glutamate excitotoxicity is emerging as a contributor to degeneration of spinal cord motoneurons in amyotrophic lateral sclerosis (ALS). Recently, we have reported that ghrelin protects motoneurons against chronic glutamate excitotoxicity through the activation of extracellular signal-regulated kinase 1/2 and phosphatidylinositol-3-kinase/Akt/glycogen synthase kinase-3β pathways. Previous studies suggest that activated microglia actively participate in the pathogenesis of ALS motoneuron degeneration. However, it is still unknown whether ghrelin exerts its protective effect on motoneurons via inhibition of microglial activation. In this study, we investigate organotypic spinal cord cultures (OSCCs) exposed to threohydroxyaspartate (THA), as a model of excitotoxic motoneuron degeneration, to determine if ghrelin prevents microglial activation. Exposure of OSCCs to THA for 3 weeks produced typical motoneuron death, and treatment of ghrelin significantly attenuated THA-induced motoneuron loss, as previously reported. Ghrelin prevented THA-induced microglial activation in the spinal cord and the expression of pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β. Our data indicate that ghrelin may act as a survival factor for motoneurons by functioning as a microglia-deactivating factor and suggest that ghrelin may have therapeutic potential for the treatment of ALS and other neurodegenerative disorders where inflammatory responses play a critical role.     

MPTP-induced dopaminergic degeneration and deficits in object recognition in rats are accompanied by neuroinflammation in the hippocampus

Emotional changes, impairment of object recognition, and neuroinflammation are seen in Parkinson's disease with dementia (PDD). Here, we show that bilateral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into the rat substantia nigra pars compacta (SNc) of Wistar rats caused degeneration of nigrostriatal dopaminergic neurons, microglial activation in the SNc and hippocampus, and cell loss in the hippocampal CA1 area. With regard to behavior, an increase in anxiety-like behavior and impairment of object recognition were observed during the fourth week after MPTP lesioning. The behavioral changes were not caused by motor impairment, since the rats had already recovered from MPTP-induced catalepsy before the tests were performed. These findings show that MPTP-induced neuroinflammation and its consequences, for example, microglial activation and cell loss in the hippocampus, may be involved in dopaminergic degeneration-related behavioral deficits and suggest that, in addition to the dopaminergic system, the limbic system may also participate in the pathophysiology of PDD. MPTP-lesioned rats are therefore proposed as a useful tool for assessing the ability of pharmacological agents to prevent recognition deficits in PDD.     

Nimodipine protects dopaminergic neurons against inflammation-mediated degeneration through inhibition of microglial activation

Nimodipine, a calcium channel blocker, has been used mainly in the therapy of cardiovascular diseases. Recently, its indications have been extended experimentally to a wider range of disorders especially some central nervous system (CNS) disorders. In this study, we investigated whether nimodipine is neuroprotective to inflammation-mediated neurodegenerative diseases. Pretreatment with nimodipine reduced the degeneration of dopaminergic (DA) neurons induced by LPS in mesencephalic neuron-glia cultures in a dose-dependent manner. The neuroprotective effect of nimodipine was attributed to the inhibition of microglial activation, since nimodipine significantly inhibited the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and prostaglandin E₂ (PGE₂) from LPS-stimulated microglia. Moreover, nimodipine was not neuroprotective to 1-methyi-4-phenylpyridinium (MPP⁺)-induced DA neurotoxicity in the absence of microglia. Mechanistic study showed that nimodipine failed to protect the degeneration of neurons in neuron-glia cultures from mice lacking functional NADPH oxidase (PHOX), a key enzyme for extracellular superoxide production in immune cells. Taken together these results suggest that nimodipine is protective to DA neurodegeneration via inhibiting the microglial-mediated oxidative stress and inflammatory response. Thus, nimodipine may be a potential therapeutic agent for the treatment of inflammation-related neurodegenerative disorders such as Parkinson's disease.     

Neuroprotective effects of neurokinin receptor one in dopaminergic neurons are mediated through Akt/PKB cell signaling pathway

Neurokinin one (NK1) receptor is Substance P (SP) receptor and it is abundantly distributed in the basal ganglia. Growing evidences were shown on their possible roles in the pathogenesis and treatment of Parkinson’s disease (PD). NK1 receptor is a kind of G-protein-coupled-receptor (GPCR) and it links to various downstream survival signaling pathways. In the present study, treatment of NK1 receptor agonist septide [(Pyr6, Pro9)-SP (6-11)] was found to ameliorate the motor deficit in 6-hydroxydopamine (6-OHDA) lesioned rats in apomorphine rotation test. Septide treatments were also demonstrated to provide neuroprotection. In 6-OHDA lesioned rats, protection of TH immunoreactive neurons and terminals in substantia nigra (SN) and striatum was found after septide treatment. In SH-SY5Y cultures, cytotoxicity of 6-OHDA was reduced by septide pretreatment. In addition, up-regulations of phosphorylated serine–threonine kinase Akt and phosphorylated mitochondrial apoptotic protein BAD were observed in both in vivo and in vitro models, indicating the inhibition of apoptotic pathway by septide. In conclusion, septide could trigger the pro-survival Akt/PKB signaling pathway and protect dopaminergic neurons in in vivo and in vitro models against 6-OHDA toxicity. Therefore septide treatment may have therapeutic implications in treatment of PD.     

Amantadine protects dopamine neurons by a dual action: reducing activation of microglia and inducing expression of GNDF in astroglia

Amantadine is commonly given to alleviate L-DOPA-induced dyskinesia of Parkinson’s disease (PD) patients. Animal and human evidence showed that amantadine may also exert neuroprotection in several neurological disorders. Additionally, it is generally believed that this neuroprotection results from the ability of amantadine to inhibit glutamatergic NMDA receptor. However, several lines of evidence questioned the neuroprotective capacity of NMDA receptor antagonists in animal models of PD. Thus the cellular and molecular mechanism of neuroprotection of amantadine remains unclear. Using primary cultures with different composition of neurons, microglia, and astroglia we investigated the direct role of these glial cell types in the neuroprotective effect of amantadine. First, amantadine protected rat midbrain cultures from either MPP⁺ or lipopolysaccharide (LPS), two toxins commonly used as PD models. Second, our studies revealed that amantadine reduced both LPS- and MPP⁺-induced toxicity of dopamine neurons through 1) the inhibition of the release of microglial pro-inflammatory factors, 2) an increase in expression of neurotrophic factors such as GDNF from astroglia. Lastly, differently from the general view on amantadine’s action, we provided evidence suggesting that NMDA receptor inhibition was not crucial for the neuroprotective effect of amantadine. In conclusion, we report that amantadine protected dopamine neurons in two PD models through a novel dual mechanism, namely reducing the release of pro-inflammatory factors from activated microglia and increasing the expression of GNDF in astroglia.     

红车轴草异黄酮抑制小胶质细胞活化保护多巴胺能神经元的研究

目的探讨从红车轴草分离的5种异黄酮芒柄花素(formononetin)、大豆黄素(daidzein)、毛蕊异黄酮(calycosin)、红车轴草素(pratensein)、德鸢尾素(irilone)对脂多糖(LPS)诱导的多巴胺能神经元损伤的保护作用。方法利用LPS建立多巴胺能神经元损伤的细胞模型,利用液闪测定法检测[3H]DA摄取力以评价多巴胺能神经元的功能,利用免疫细胞化学技术进行酪氨酸羟化酶(tyrosine hydroxylase,TH)染色观测多巴胺能神经元的形态和数目,利用免疫细胞化学技术进行OX-42染色观测小胶质细胞的形态和数目。NO测定依据Griess反应,TNF-α测定采用酶联免疫法,超氧自由基测定采用细胞色素C还原法。结果从红车轴草分离的5种异黄酮均以剂量依赖方式减轻大鼠中脑原代混合培养体系中LPS诱导的多巴胺摄取力的下降和多巴胺能神经元数目的下降。而且,这5种异黄酮还抑制中脑混合培养体系和小胶质细胞纯化体系中LPS诱导的小胶质细胞的活化和TNF-α、NO和超氧自由基的生成。并且,这5种异黄酮作用强弱的顺序依次为:pratensein>daidzein>calycosin>formononetin>irilone。结论从红车轴草分离的5种异黄酮对LPS诱导的多巴胺能神经元的损伤均具有不同程度的保护作用,且保护作用强弱的顺序依次为:pratensein>daidzein>calycosin>formononetin>irilone,抑制小胶质细胞的活化是其作用机制之一。     

DL0410 attenuates oxidative stress and neuroinflammation via BDNF/TrkB/ERK/CREB and Nrf2/HO-1 activation

Oxidative stress and neuroinflammation have been deeply associated with Alzheimer’s disease. DL0410 is a novel acetylcholinesterase inhibitor with potential anti-oxidative effects in AD-related animal models, while the specific mechanism has not been fully clarified. In this study, DL0410 was predicted to be related to the modification of cell apoptosis, oxidation-reduction process, inflammatory response and ERK1/ERK2 cascade by in silico target fishing and GO enrichment analysis. Then the possible protective effects of DL0410 were evaluated by hydrogen peroxide (H₂O₂)-induced oxidative stress model and lipopolysaccharides (LPS)-induced neuroinflammation model H₂O₂ decreased the viability of SH-SY5Y cells, induced malondialdehyde (MDA) accumulation, mitochondrial membrane potential (Δψm) loss and cell apoptosis, which could be reversed by DL0410 dose-dependently, indicating that DL0410 protected SH-SY5Y cells against H₂O₂-mediated oxidative stress. Western blot analysis showed that DL0410 increased the H₂O₂-triggered down-regulated TrkB, ERK and CREB phosphorylation and the expression of BDNF. In addition, TrkB inhibitor ANA-12, ERK inhibitor SCH772984 and CREB inhibitor 666-15 eliminated the inhibition of DL0410 on MDA accumulation and Δψm loss. Furthermore, DL0410 attenuates inflammatory responses and ROS production in LPS-treated BV2 cells, which is responsible for Nrf2 and HO-1 up-regulation. The present study demonstrates that DL0410 is a potential activator of the BDNF/TrkB/ERK/CREB and Nrf2/HO-1 pathway and may be a potential candidate for regulating oxidative stress and neuroinflammatory response in the brain. Together, the results showed that DL0410 is a promising drug candidate for treating AD and possibly other nervous system diseases associated with oxidative stress and neuroinflammation.     

Pramipexole prevents neurotoxicity induced by oligomers of beta-amyloid

Here we demonstrate that pramipexole, an antiparkinsonian dopamine receptor agonist drug, exerts neuroprotective effects against beta-amyloid neurotoxicity. Using a specific protocol to test individually oligomers, fibrils, or unaggregated amyloid beta-peptide, we found pramipexole able to protect cells against oligomers and fibrils. Unaggregated amyloid beta-peptide was found unable to cause cell death. Fibrils and oligomers were also found to produce elevated amount of free radicals, and this effect was prevented by pramipexole. We propose pramipexole may become in the future a coadjuvant in the treatment of neuropathologies, besides Parkinson's disease, where amyloid beta-peptide-mediated oxidative injury exerts a relevant role.     

PPAR-γ agonist rosiglitazone prevents inflammatory periodontal bone loss by inhibiting osteoclastogenesis

Rosiglitazone (RGZ), an oral anti-hyperglycemic agent used for non-insulin-dependent diabetes mellitus, is a high-affinity synthetic agonist for peroxisome proliferator-activated receptor-γ (PPAR-γ). Both in vitro and in vivo experiments have also revealed that RGZ possesses anti-inflammatory properties. Therefore, in the present study, we investigated the anti-inflammatory effects of RGZ in a rat model of periodontal disease induced by ligature placed around the mandible first molars of each animal. Male Wister rats were divided into four groups: 1) animals without ligature placement receiving administration of empty vehicle (control); 2) animals with ligature receiving administration of empty vehicle; 3) animals with ligature receiving administration with oral RGZ (10 mg/kg/day); and 4) animals with ligature receiving administration of subcutaneous RGZ (10 mg/kg/day). Thirty days after induction of periodontal disease, the animals were sacrificed, and mandibles and gingival tissues were removed for further analysis. An in vitro assay was also employed to test the inhibitory effects of RGZ on osteoclastogenesis. Histomorphological and immunohistochemical analyses of periodontal tissue demonstrated that RGZ-treated animals presented decreased bone resorption, along with reduced RANKL expression, compared to those animals with ligature, but treated with empty vehicle. Corresponding to such results obtained from in vivo experiments, RGZ also suppressed in vitro osteoclast differentiation in the presence of RANKL in MOCP-5 osteoclast precursor cells, along with the down-regulation of the expression of RANKL-induced TRAP mRNA. These data indicated that RGZ may suppress the bone resorption by inhibiting RANKL-mediated osteoclastogenesis elicited during the course of experimental periodontitis in rats.     

螺旋藻多糖对MPTP致多巴胺能神经元损伤的保护

目的探讨螺旋藻多糖(PSP)对MPTP制备的C57BL小鼠帕金森病(PD)模型多巴胺能神经元的保护作用。方法C57BL小鼠分5组:对照组、MPTP组、PSP高、中、低剂量预处理+MPTP组。用免疫组化、RT-PCR和HPLC-ECD方法检测黑质中酪氨酸羟化酶(TH)和多巴胺转运体(DAT)免疫反应阳性表达水平,TH和DAT mRNA表达水平及纹状体中多巴胺(DA)及其代谢产物3,4-二羟苯乙酸(DOPAC)和高香草酸(HVA)的含量。结果模型小鼠黑质中TH和DAT免疫阳性细胞数目减少,TH和DAT mRNA表达水平降低,纹状体中DA、DOPAC和HVA含量降低(P<0.01)。PSP预处理组与模型组相比,TH和DAT免疫阳性细胞数目增加,TH和DAT mRNA表达升高,DA、DOPAC和HVA含量升高(P<0.05)。结论PSP对MPTP所致C57BL小鼠PD模型的多巴胺能神经元有保护作用。     

D2 receptor activation relieves pain hypersensitivity by inhibiting superficial dorsal horn neurons in parkinsonian mice

Chronic pain is a common and undertreated nonmotor symptom in Parkinson’s disease(PD).Although chronic pain is improved by L-dopa in some PD patients,the underlying mechanisms remain unclear.In this study,we established PD mice by unilateral microinjection of 6-OHDA in the medial forebrain bundle to investigate the contribution of spinal cord dopamine receptors to parkinsonian pain hypersensitivity.The von Frey filament tests and thermal pain tests revealed that these PD mice displayed decreased nociceptive thresholds in both hindpaws;intrathecal injection of L-dopa or apomorphine significantly increased the mechanical and thermal nociceptive thresholds,and the analgesic effect was mimicked by ropinirole(a D2 receptor agonist),but not SKF38393(a D1/D5 receptor agonist),and blocked by sulpiride(a D2 receptor antagonist),but not SKF83566(a D1/D5 receptor antagonist).Whole-cell recordings in lumber spinal cord slices showed that superficial dorsal horn(SDH)neurons in PD mice exhibited hyperexcitability,including more depolarized resting membrane potentials and more action potentials evoked by depolarizing current steps,which were mitigated by ropinirole.Furthermore,ropinirole inhibited the frequency of spontaneous excitatory postsynaptic currents(sEPSCs)in SDH neurons more strongly in PD mice than in control mice.However,sulpiride caused less disinhibition of sEPSCs in PD mice than in control mice.Taken together,our data reveal that pain hypersensitivity in PD mice is associated with hyperexcitability of SDH neurons,and both events are reversed by activation of spinal D2 receptors.Therefore,spinal D2 receptors can be promising therapeutic targets for the treatment of PD pain.     

Effects of nicotine on hydroxyl free radical formation in vitro and on MPTP-induced neurotoxicity in vivo

Parkinson’s disease (PD) is one of the most frequent disorders of the basal ganglia. From epidemiological studies there is a controversial discussion on the question whether tobacco smoking is correlated with a decreased incidence of PD. The present study aimed to elucidate the role of nicotine and its potential neuroprotective effects in a rodent model of PD. These effects may be related to an altered hydroxyl radical formation; this possibility was studied in vitro. Nicotine and α-phenyl-N-tert-butyl nitrone (PBN) were examined in a cell-free in vitro Fenton system (Fe³⁺/EDTA + H₂O₂) for their radical scavenging properties using the salicylate trapping method. Salicylic acid (0.5 mM) was incubated in the presence and absence of nicotine or PBN and the main products of the reaction of hydroxyl radicals with salicylic acid, namely 2,3- and 2,5-dihydroxybenzoic acid, were immediately determined using HPLC in combination with electrochemical detection. Nicotine and PBN were both able to significantly reduce hydroxyl radical levels at concentrations of 1, 2.5 and 5 mM. Interestingly, at 5 mM nicotine was able to reduce hydroxyl radical levels significantly more than the radical scavenger PBN (5 mM). To investigate the in vivo effects of nicotine, male C57BL/6 mice were used in the MPTP mouse model of PD. Nicotine (0.1 or 0.4 mg/kg s.c.) was administered twice daily for a period of 14 days. On day 8 a single injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg s.c.) was given as well as an enhanced protocol of nicotine treatment (0.1 or 0.4 mg/kg s.c., 30 min before MPTP and 30, 90, 210, 330, 450, 570 min after MPTP) for a total of seven injections of nicotine. High dosage nicotine treatment significantly increased the MPTP-induced loss of body weight and resulted in a significantly decreased striatal dopamine content and an increased dopamine turnover in comparison with the MPTP-treated controls at day 15. However, the lower dosage of nicotine did not significantly alleviate the MPTP-induced effects, although some parameters showed a slight tendency in this direction. These results demonstrate that in vitro nicotine has radical scavenging properties which might suggest neuroprotective effects. In vivo experiments with nicotine, however, showed that a low dosage of nicotine did not alleviate the MPTP-induced dopamine depletion, but a large dosage even enhanced it. Received: 20 March 1998 / Accepted: 23 June 1998     

SIRT3介导褪黑激素保护帕金森病多巴胺能神经元的作用机制

目的研究SIRT3在褪黑激素保护帕金森病(Parkinson’s disease,PD)多巴胺能神经元中的作用。方法48只小鼠随机分为对照组、模型组和治疗组,治疗组小鼠给予褪黑激素(10 mg·kg-1)和MPTP(30 mg·kg-1)腹腔注射,模型组小鼠给予MPTP腹腔注射,对照组小鼠同时给予等量生理盐水,褪黑激素连续给药14 d。采用免疫组化分析黑质TH、Iba-1表达情况,ELISA法检测中脑组织氧化应激指标(ROS、MDA、SOD)及炎症因子(TNF-α、IL-1β)水平,实时定量PCR分析SIRT3 mRNA水平,免疫荧光和Western blot检测蛋白表达情况。结果与对照组比较,模型组小鼠黑质TH表达减少、Iba-1表达增多,中脑组织氧化应激与炎症损伤明显增强,黑质SIRT3 mRNA和蛋白表达水平明显降低,SOD2蛋白表达减少,iNOS蛋白表达增多,组间比较差异均具有统计学意义( P <0.05)。治疗组小鼠经褪黑激素干预后,TH表达增多、Iba-1表达减少,氧化应激与炎症损伤明显减弱,SIRT3 mRNA和蛋白表达水平升高,SOD2蛋白表达上调,iNOS蛋白表达下调,与模型组比较,差异均具有统计学意义( P <0.05)。 结论 褪黑激素通过上调SIRT3表达抵抗PD多巴胺能神经元损伤,作用机制与其抑制小胶质细胞激活减轻氧化应激和炎症损伤有关。     

SEA0400, a specific Na+/Ca2+ exchange inhibitor, prevents dopaminergic neurotoxicity in an MPTP mouse model of Parkinson's disease

We have recently shown that the Na⁺/Ca²⁺ exchanger (NCX) is involved in nitric oxide (NO)-induced cytotoxicity in cultured astrocytes and neurons. However, there is no in vivo evidence suggesting the role of NCX in neurodegenerative disorders associated with NO. NO is implicated in the pathogenesis of neurodegenerative disorders such as Parkinson’s disease. This study examined the effect of SEA0400, the specific NCX inhibitor, on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurotoxicity, a model of Parkinson’s disease, in C57BL/6J mice. MPTP treatment (10 mg/kg, four times at 2-h intervals) decreased dopamine levels in the midbrain and impaired motor coordination, and these effects were counteracted by S-methylthiocitrulline, a selective neuronal NO synthase inhibitor. SEA0400 protected against the dopaminergic neurotoxicity (determined by dopamine levels in the midbrain and striatum, tyrosine hydroxylase immunoreactivity in the substantia nigra and striatum, striatal dopamine release, and motor deficits) in MPTP-treated mice. SEA0400 had no radical-scavenging activity. SEA0400 did not affect MPTP metabolism and MPTP-induced NO production and microglial activation, while it attenuated MPTP-induced increases in extracellular signal-regulated kinase (ERK) phosphorylation and lipid peroxidation product, thiobarbituric acid reactive substance. These findings suggest that SEA0400 protects against MPTP-induced neurotoxicity probably by blocking ERK phosphorylation and lipid peroxidation which are downstream of NCX-mediated Ca²⁺ influx.     

Hyperlipidemia-induced lipotoxicity and immune activation in rats are prevented by curcumin and rutin

We assessed the effects of curcumin, rutin, and the association of rutin and curcumin in organs of hyperlipidemic rats. Rutin and curcumin have notable antioxidant and anti-inflammatory actions, so we hypothesized that their association would enhance their beneficial effects. Hyperlipidemia results in lipotoxicity and affects several organs. Lipotoxicity is not only an outcome of lipid accumulation in non-adipose tissues but also a result of the hyperlipidemia-associated inflammation and oxidative stress. Wistar rats were treated with rutin and curcumin for 30 days before the induction of acute hyperlipidemia by Poloxamer-407. After 36 h, the animals were euthanized for collection of blood and organs. Untreated hyperlipidemic rats showed higher uric acid and albumin levels in the serum and increased spleen size and ADA activity. Rutin, curcumin and the association reduced the spleen size by 20% and ADA activity by 23, 28, and 27%, respectively. Rats pretreated with rutin showed reduced lipid damage in the liver (40%) and the kidney (44%), and the protein damage was also reduced in the liver (75%). The lipid damage was decreased by 40% in the liver, and 56% in the kidney of rats pretreated with curcumin. The association reduced lipid damage by 50% and 36%, and protein damage by 77% and 64% in the liver and kidney, respectively. Rutin better prevented the decrease in the antioxidant defenses, increasing SOD by 34%, CAT by 246% and GST by 84% in the liver, as well as SOD by 119% and GST by 190% in the kidney. Also, analyses of blood and spleen parameters of untreated and pretreated non-hyperlipidemic rats showed no signs of immunotoxicity. Despite showing protective effects, the association did not perform better than the isolated compounds. Here, we showed that rutin and/or curcumin reestablished the immune homeostasis and redox balance disrupted by hyperlipidemia in peripheral organs of rats.     

Papaverine Exerts Neuroprotective Effect by Inhibiting NLRP3 Inflammasome Activation in an MPTP-Induced Microglial Priming Mouse Model Challenged with LPS

Microglial priming is the process of microglial proliferation and activation in response to neurodegeneration and abnormal protein accumulation. Priming makes microglia susceptible to secondary inflammatory stimuli and causes exaggerated inflammatory responses. In the present study, we established a microglial priming model in mice by administering a single injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 20 mg/kg). MPTP induced microglial activation without dopaminergic degeneration; however, subsequent treatment with a sub-toxic dose of lipopolysaccharides (LPS) induced an amplified inflammatory response and caused nigrostriatal dopaminergic degeneration. These pathological and inflammatory changes, including microglial activation and dopaminergic cell loss in the substantia nigra (SN) area were reversed by papaverine (PAP) administration. In addition, MPTP/LPS enhanced interleukin-1β (IL-1β) expression and processing via nod-like receptor protein 3 (NLRP3) inflammasome activation in the SN region of mice. However, PAP treatment suppressed inflammasome activation and subsequent IL-1β maturation. Moreover, PAP inhibited nuclear factor-κB (NF-κB) and enhanced cAMP-response element binding protein (CREB) activity in the SN of MPTP/LPS mice. These results suggest that PAP inhibits the activation of NLRP3 inflammasome by modulating NF-κB and CREB signaling pathways, which results in reduced microglial activation and neuronal cell death. Thus, PAP may be a potential candidate for the treatment of Parkinsons’s disease, which is aggravated by systemic inflammation.