Asiaticoside exerts neuroprotection through targeting NLRP3 inflammasome activation.

BACKGROUND: Parkinson's disease (PD), a neurodegenerative disorder, is characterized by motor symptoms due to the progressive loss of dopaminergic neurons in the substantia nigra (SN) and striatum (STR), alongside neuroinflammation. Asiaticoside (AS), a primary active component with anti-inflammatory and neuroprotective properties, is derived from Centella asiatica. However, the precise mechanisms through which AS influences PD associated with inflammation are not yet fully understood. PURPOSE: This study aimed to explore the protective mechanism of AS in PD. METHODS: Targets associated with AS and PD were identified from the Swiss Target Prediction, Similarity Ensemble Approach, PharmMapper, and GeneCards database. A protein-protein interaction (PPI) network was constructed to identify potential therapeutic targets. Concurrently, GO and KEGG analyses were performed to predict potential signaling pathways. To validate these mechanisms, the effects of AS on 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD in mice were investigated. Furthermore, neuroinflammation and the activation of the NLRP3 inflammasome were assessed to confirm the anti-inflammatory properties of AS. In vitro experiments in BV2 cells were then performed to investigate the mechanisms of AS in PD. Moreover, CETSA, molecular docking, and molecular dynamics simulations (MDs) were performed for further validation. RESULTS: Network pharmacology analysis identified 17 potential targets affected by AS in PD. GO and KEGG analyses suggested the biological roles of these targets, demonstrating that AS interacts with 149 pathways in PD. Notably, the NOD-like receptor signaling pathway was identified as a key pathway mediating AS's effect on PD. In vivo studies demonstrated that AS alleviated motor dysfunction and reduced the loss of dopaminergic neurons in MPTP-induced PD mice. In vitro experiments demonstrated that AS substantially decreased IL-1ß release in BV2 cells, attributing this to the modulation of the NLRP3 signaling pathway. CETSA and molecular docking studies indicated that AS forms a stable complex with NLRP3. MDs suggested that ARG578 played an important role in the formation of the complex. CONCLUSION: In this study, we first predicted that the potential target and pathway of AS's effect on PD could be NLRP3 protein and NOD-like receptor signaling pathway by network pharmacology analysis. Further, we demonstrated that AS could alleviate symptoms of PD induced by MPTP through its interaction with the NLRP3 protein for the first time by in vivo and in vitro experiments. By binding to NLRP3, AS effectively inhibits the assembly and activation of the inflammasome. These findings suggest that AS is a promising inhibitor for PD driven by NLRP3 overactivation.

Folic Acid Rescues Dopaminergic Neurons in MPTP-Induced Mice by Inhibiting the NLRP3 Inflammasome and Ameliorating Mitochondrial Impairment.

Parkinson's disease (PD) is marked by the degeneration of dopaminergic neurons of the substantia nigra (SN), with neuroinflammation and mitochondrial dysfunction being key contributors. The neuroprotective potential of folic acid (FA) in the dopaminergic system of PD was assessed in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model. MPTP (20 mg/kg of body weight) was administered to C57BL/6J mice to simulate PD symptoms followed by FA treatment (5 mg/kg of body weight). Behavioral tests, pole, rotarod, and open-field tests, evaluated motor function, while immunohistochemistry, ELISA, RT-qPCR, and Western blotting quantified neuroinflammation, oxidative stress markers, and mitochondrial function. FA supplementation considerably improved motor performance, reduced homocysteine levels and mitigated oxidative damage in the SN. The FA-attenuated activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome lessened glial cell activity and reduced neuroinflammation. At the molecular level, FA reduced DNA damage, downregulated phosphorylated p53, and induced the expression of peroxisome proliferator-activated receptor α coactivator 1α (PGC-1α), enhancing mitochondrial function. Therefore, FA exerts neuroprotection in MPTP-induced PD by inhibiting neuroinflammation via NLRP3 inflammasome suppression and promoting mitochondrial integrity through the p53-PGC-1α pathway. Notable limitations of our study include its reliance on a single animal model and the incompletely elucidated mechanisms underlying the impact of FA on mitochondrial dynamics. Future investigations will explore the clinical utility of FA and its molecular mechanisms, further advancing it as a potential therapeutic for managing and delaying the progression of PD.

Harnessing the neuroprotective effect of oral administration of benfotiamine in MPTP induced Parkinson's disease in rats.

The study was performed to evaluate the neuroprotective effects of Benfotiamine (BFT) in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) in rats. The rats were given daily doses of BFT (100 mg/kg, 200 mg/kg) through oral administration for 42 days. The rats were given a single bilateral dosage of MPTP (0.1 mg/nostril) intranasally once before the drug treatment to induce PD. On day 42, the animals were subjected to various behavioral paradigms. Post-treatment with BFT for 42 days significantly improved the motor and nonmotor fluctuations of MPTP. The results demonstrated that treatment with BFT ameliorated MPTP-induced disorders in behavior, body balance, and dopamine levels in the mid-brain. Among the post-treated groups, a high dose of BFT was the most effective treatment. Mean values are indicated in ±SEM, n = 5***(p < 0.001) when compared with the vehicle control, n = 5 ### (p < 0.001) when compared with the disease control; (p < 0.001) when compared with the BFT per se; (p < 0.001) when compared with the low dose of BFT; (p < 0.001) when compared with the high dose of BFT. Our finding suggests that BFT contributed to superior antioxidant, and anti-inflammatory and could be a novel therapeutic method for PD management. In conclusion, BFT could be a potential drug candidate for curbing and preventing PD.

TMT-based quantitative proteomics analysis of neuroprotective effects of Forsythoside A on the MPTP-induced Parkinson's disease mouse model.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder characteristized by the presence of dyskinesia and the progressive loss of dopaminergic neurons. Although certain drugs can mitigate the symptoms of PD, they are unable to delay the disease progression, and their prolonged use may result in complications. Therefore, there exists an urgent necessity to identify potential agents that can effectively delay PD progression with fewer side effects. Recent research has unveiled that several traditional Chinese medicines (TCM) exhibit neuroprotective properties in various models pertinent to PD. Forsythoside A (FSA), the primary bioactive compound derived from TCM Lianqiao, has undergone extensive research in animal models of Alzheimer's disease and cerebral ischemia. However, the investigation into the impact of FSA on PD is limited in existing research. In this study, we aimed to evaluate the neuroprotective effects of FSA on MPTP-induced PD mouse model. FSA demonstrated significant improvements in the behavioral and neuropathological changes triggered by MPTP in mice. Furthermore, it exerted a suppressive effect on the activations of astrocyte and microglia. Meanwhile, Tandem mass tag (TMT)-based quantitative proteomics of striatal tissue and bioinformatics analysis were performed to elucidate the underlying mechanisms of FSA on PD mouse model. Proteomics demonstrated a total of 68 differentially expressed proteins (DEPs) were identified between HFSA and MPTP groups including 26 upregulated and 42 downregulated. Systematic bioinformatics analysis of the 68 DEPs illustrated that they were predominantly related to estrogen signaling pathway and calcium signaling pathway. The related DEPs (PLCß4, Grm2, HPAC and Cox4i1) expression levels were verified by Western blot. FSA effectively restored the altered expression of the four DEPs induced by MPTP. Summarily, FSA exerted remarkable neuroprotective effects in MPTP-induced mice. Further, our research may provide proteomics insights that contribute to the further exploration of FSA as a potential treatment for PD.

The gut microbiota metabolite butyrate mitigates MPTP/MPP+ -induced Parkinson's disease by inhibiting the JAK2/STAT3 signaling pathway.

Butyrate (BU), a gut microbiota-derived metabolite, has been reported to play a neuroprotective role in Parkinson's disease (PD). However, the specific molecular mechanism of BU has not been fully interpreted. This work aimed to verify the protective effects of BU against MPTP/MPP+ -induced neurotoxicity and explore the mechanisms involved. The results showed that BU protected against MPTP-induced motor dysfunction and decreased tyrosine hydroxylase (TH) and dopamine transporter (DAT) levels. Additionally, BU pretreatment improved PC12 cell viability and reduced MPP+ -induced PC12 cell apoptosis. BU treatment also attenuated MPP+ -stimulated oxidative stress and inflammatory response in PC12 cells. Furthermore, BU inhibited MPTP/MPP+ -induced hyperactivation of the JAK2/STAT3 signaling in mice and PC12 cells. Besides, a JAK2 agonist, Coumermycin A1 (C-A1), substantially reversed BU-mediated inhibition on JAK2/STAT3 phosphorylation in MPP+ -challenged PC12 cells and abated BU-induced repression on MPP+ -triggered apoptosis, oxidative stress, and inflammatory response in PC12 cells. To sum up, BU might exert neuroprotective effects against MPP+ /MPTP-induced neurotoxicity by inactivating the JAK2/STAT3 signaling.

Novel FABP3 ligand, HY-11-9, ameliorates neuropathological deficits in MPTP-induced Parkinsonism in mice.

Parkinson's disease (PD) is characterized by dopaminergic (DAergic) neuronal loss in the substantia nigra pars compacta (SNpc), resulting from α-synuclein (αSyn) toxicity. We previously reported that αSyn oligomerization and toxicity are regulated by the fatty-acid binding protein 3 (FABP3), and the therapeutic effects of the FABP3 ligand, MF1, was successfully demonstrated in PD models. Here, we developed a novel and potent ligand, HY-11-9, which has a higher affinity for FABP3 (Kd = 11.7 ± 8.8) than MF1 (Kd = 302.8 ± 130.3). We also investigated whether the FABP3 ligand can ameliorate neuropathological deterioration after the onset of disease in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism. Motor deficits were observed two weeks after MPTP treatment. Notably, oral administration of HY-11-9 (0.03 mg/kg) improved motor deficits in both beam-walking and rotarod tasks, whereas MF1 failed to improve the motor deficits in both tasks. Consistent with the behavioral tasks, HY-11-9 recovered dopamine neurons from MPTP toxicity in the substantia nigra and ventral tegmental areas. Furthermore, HY-11-9 reduced the accumulation of phosphorylated-serine129-α-synuclein (pS129-αSyn) and colocalization with FABP3 in tyrosine hydroxylase (TH)-positive DA neurons in the PD mouse model. Overall, HY-11-9 significantly improved MPTP-induced behavioral and neuropathological deterioration, suggesting that it may be a potential candidate for PD therapy.

4-Aminopyridine Protects Nigral Dopaminergic Neurons in the MPTP Mouse Model of Parkinson's Disease.

Various pharmacological blockers targeting K+ channel have been identified to be related to the treatment of Parkinson's disease (PD). Previous studies showed that 4-Aminopyridine (4-AP), a wide-spectrum K+ channel blocker, was able to attenuate apomorphine-induced rotation in parkinsonism rats, indicating the possible beneficial effects in attenuation of PD motor symptoms. However, it is unclear whether 4-AP exhibits neuroprotective effects against the neurodegeneration of substantia nigra (SN)-striatum system in PD. In this study, the 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse model was employed to evaluate the neuroprotective effects of 4-AP. Results showed that 4-AP inhibited MPTP-induced dopaminergic neuronal loss in the SN as well as dopamine depletion in the striatum. Behavior indexes of open field test and rotarod test confirmed that 4-AP attenuated MPTP-induced motor deficits. We also showed that 4-AP treatment could significantly attenuate the MPTP-induced increase in malonaldehyde (MDA) levels and decrease in superoxide dismutase (SOD) levels. Additionally, MPTP significantly reduced the Bcl-2 expression and promoted the Caspase-3 activation; 4-AP protected dopaminergic neurons against MPTP-induced neurotoxicity by reversing these changes. These results indicate that 4-AP exerts a neuroprotective effect on dopaminergic neurons against MPTP by decreasing oxidative stress and apoptosis. This provides a promising therapeutic target for the treatment of PD.

Feruloylated oligosaccharides ameliorate MPTP-induced neurotoxicity in mice by activating ERK/CREB/BDNF/TrkB signalling pathway.

BACKGROUND: Feruloylated oligosaccharides (FOs) are natural esterification products of ferulic acid and oligosaccharides. STUDY DESIGN: In this study, we examined whether FOs contribute to the ensured survival of nigrostriatal dopamine neurons and inhibition of neuroinflammation in Parkinson's disease (PD). METHODS: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg) was injected intraperitoneally into mice to establish a Parkinson's disease (PD) mouse model. FOs (15 and 30 mg/kg) were orally administered daily to the MPTP-treated mice. The rotarod test, balance beam test, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), quantitative PCR (qPCR), and western blot analyses were performed to examine the neuroprotective effects of FOs on MPTP-treated mice. RESULTS: Our study indicated that FOs increased the survival of dopamine neurons in the substantia nigra pars compacta (SNc) of the MPTP-treated mice. The neuroprotective effects of FOs were accompanied by inhibited glial activation and reduced inflammatory cytokine production. The mechanistic experiments revealed that the neuroprotective effects of FOs might be mediated through the activation of the ERK/CREB/BDNF/TrkB signalling pathway. CONCLUSION: This study provides new insights into the mechanism underlying the anti-neuroinflammatory effect of phytochemicals and may facilitate the development of dietary supplements for PD patients. Our results indicate that FOs can be used as potential modulators for the prevention and treatment of PD.

A Newly Identified Monoterpenoid-Based Small Molecule Able to Support the Survival of Primary Cultured Dopamine Neurons and Alleviate MPTP-Induced Toxicity In Vivo.

Parkinson's disease (PD) is the most common age-related movement disorder characterized by the progressive loss of nigrostriatal dopaminergic neurons. To date, PD treatment strategies are mostly based on dopamine replacement medicines, which can alleviate motor symptoms but do not slow down the progression of neurodegeneration. Thus, there is a need for disease-modifying PD therapies. The aim of this work was to evaluate the neuroprotective effects of the novel compound PA96 on dopamine neurons in vivo and in vitro, assess its ability to alleviate motor deficits in MPTP- and haloperidol-based PD models, as well as PK profile and BBB penetration. PA96 was synthesized from (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl) cyclohex-3-ene-1,2-diol (Prottremin) using the original three-step stereoselective procedure. We found that PA96: (1) supported the survival of cultured näive dopamine neurons; (2) supported the survival of MPP+-challenged dopamine neurons in vitro and in vivo; (3) had chemically appropriate properties (synthesis, solubility, etc.); (4) alleviated motor deficits in MPTP- and haloperidol-based models of PD; (5) penetrated the blood-brain barrier in vivo; and (6) was eliminated from the bloodstream relative rapidly. In conclusion, the present article demonstrates the identification of PA96 as a lead compound for the future development of this compound into a clinically used drug.

Anti-Inflammatory and Neuroprotective Effects of Morin in an MPTP-Induced Parkinson's Disease Model.

Neurodegenerative diseases such as Parkinson's disease (PD) are known to be related to oxidative stress and neuroinflammation, and thus, modulating neuroinflammation offers a possible means of treating PD-associated pathologies. Morin (2',3,4',5,7-pentahydroxy flavone) is a flavonol with anti-oxidative and anti-inflammatory effects found in wines, herbs, and fruits. The present study was undertaken to determine whether a morin-containing diet has protective effects in an MPTP-induced mouse model of PD. Mice were fed a control or morin diet for 34 days, and then MPTP (30 mg/kg, i.p.) was administered daily for 5 days to induce a PD-like pathology. We found that dietary morin prevented MPTP-induced motor dysfunction and ameliorated dopaminergic neuronal damage in striatum (STR) and substantia nigra (SN) in our mouse model. Furthermore, MPTP-induced neuroinflammation was significantly reduced in mice fed morin. In vitro studies showed that morin effectively suppressed glial activations in primary microglia and astrocytes, and biochemical analysis and a docking simulation indicated that the anti-inflammatory effects of morin were mediated by blocking the extracellular signal-regulated kinase (ERK)-p65 pathway. These findings suggest that morin effectively inhibits glial activations and has potential use as a functional food ingredient with therapeutic potential for the treatment of PD and other neurodegenerative diseases associated with neuroinflammation.

Neuroprotective Potential of HC070, a Potent TRPC5 Channel Inhibitor in Parkinson's Disease Models: A Behavioral and Mechanistic Study.

Transient receptor potential canonical 5 (TRPC5) channels are predominantly expressed in the striatum and substantia nigra of the brain. These channels are permeable to calcium ions and are activated by oxidative stress. The physiological involvement of TRPC5 channels in temperature and mechanical sensation is well documented; however, evidence for their involvement in the pathophysiology of neurodegenerative disorders like Parkinson's disease (PD) is sparse. Thus, in the present study, the role of TRPC5 channels and their associated downstream signaling was elucidated in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/1-methyl-4-phenylpyridinium (MPTP/MPP+) model of PD. Bilateral intranigral administration of MPTP and 24 h MPP+ exposure were performed to induce PD in the Sprague-Dawley rats and SH-SY5Y cells, respectively. MPTP led to behavioral anomalies and TRPC5 overexpression accompanied by increased calcium influx, apoptosis, oxidative stress, and mitochondrial dysfunctions. In addition, tyrosine hydroxylase (TH) expression was significantly lower in the midbrain and substantia nigra compared to sham animals. Intraperitoneal administration of potent and selective TRPC5 inhibitor, HC070 (0.1 and 0.3 mg/kg) reversed the cognitive and motor deficits seen in MPTP-lesioned rats. It also restored the TH and TRPC5 expression both in the striatum and midbrain. Furthermore, in vitro and in vivo studies suggested improvements in mitochondrial health along with reduced oxidative stress, apoptosis, and calcium-mediated excitotoxicity. Together, these results showed that inhibition of TRPC5 channels plays a crucial part in the reversal of pathology in the MPTP/MPP+ model of Parkinson's disease.

Characterization of retinal function and structure in the MPTP murine model of Parkinson's disease.

In addition to well characterized motor symptoms, visual disturbances are increasingly recognized as an early manifestation in Parkinson's disease (PD). A better understanding of the mechanisms underlying these changes would facilitate the development of vision tests which can be used as preclinical biomarkers to support the development of novel therapeutics for PD. This study aims to characterize the retinal phenotype of a mouse model of dopaminergic dysfunction and to examine whether these changes are reversible with levodopa treatment. We use a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD to characterize the neurotoxic effects of MPTP on in vivo retinal function (electroretinography, ERG), retinal structure (optical coherence tomography, OCT) and retinal dopaminergic cell number (tyrosine hydroxylase immunohistochemistry, IHC) at two time points (21 and 45 days) post MPTP model induction. We also investigate the effect of levodopa (L-DOPA) as a proof-of-principle chronic intervention against MPTP-induced changes in the retina. We show that MPTP decreases dopaminergic amacrine cell number (9%, p < 0.05) and that a component of the ERG that involves these cells, in particular oscillatory potential (OP) peak timing, was significantly delayed at Day 45 (7-13%, p < 0.01). This functional deficit was paralleled by outer plexiform layer (OPL) thinning (p < 0.05). L-DOPA treatment ameliorated oscillatory potential deficits (7-13%, p < 0.001) in MPTP animals. Our data suggest that the MPTP toxin slows the timing of inner retinal feedback circuits related to retinal dopaminergic pathways which mirrors findings from humans with PD. It also indicates that the MPTP model causes structural thinning of the outer retinal layer on OCT imaging that is not ameliorated with L-DOPA treatment. Together, these non-invasive measures serve as effective biomarkers for PD diagnosis as well as for quantifying the effect of therapy.

SUN11602, a bFGF mimetic, modulated neuroinflammation, apoptosis and calcium-binding proteins in an in vivo model of MPTP-induced nigrostriatal degeneration.

BACKGROUND: Parkinson's disease (PD) is the second most frequent neurodegenerative disease. PD etiopathogenesis is multifactorial and not yet fully known, however, the scientific world advised the establishment of neuroinflammation among the possible risk factors. In this field, basic fibroblast growth factor/fibroblast growth factor receptor-1 (bFGF/FGFR1) could be a promising way to treat CNS-mediated inflammation; unfortunately, the use of bFGF as therapeutic agent is limited by its side effects. The novel synthetic compound SUN11602 exhibited neuroprotective activities like bFGF. With this perspective, this study aimed to evaluate the effect of SUN11602 administration in a murine model of MPTP-induced dopaminergic degeneration. METHODS: Specifically, nigrostriatal degeneration was induced by intraperitoneal injection of MPTP (80 mg/kg). SUN11602 (1 mg/kg, 2.5 mg/kg, and 5 mg/kg) was administered daily by oral gavage starting from 24 h after the first administration of MPTP. Mice were killed 7 days after MPTP induction. RESULTS: The results obtained showed that SUN11602 administration significantly reduced the alteration of PD hallmarks, attenuating the neuroinflammatory state via modulation of glial activation, NF-κB pathway, and cytokine overexpression. Furthermore, we demonstrated that SUN11602 treatment rebalanced Ca2+ overload in neurons by regulating Ca2+-binding proteins while inhibiting the apoptotic cascade. CONCLUSION: Therefore, in the light of these findings, SUN11602 could be considered a valuable pharmacological strategy for PD.

Preventative effects of 1-methyl-1,2,3,4-tetrahydroisoquinoline derivatives (N-functional group loading) on MPTP-induced parkinsonism in mice.

1,2,3,4-tetrahydroisoquinoline (TIQ) is endogenously present in the human brain, and some of its derivatives are thought to contribute to the induction of Parkinson's disease (PD)-like signs in rodents and primates. In contrast, the endogenous TIQ derivative 1-methyl-TIQ (1-MeTIQ) is reported to be neuroprotective. In the present study, we compared the effects of artificially modified 1-MeTIQ derivatives (loading an N-propyl, N-propenyl, N-propargyl, or N-butynyl group) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD-like signs in mice. In a behavioral study, MPTP-induced bradykinesia was significantly decreased by all compounds. However, only 1-Me-N-propargyl-TIQ showed an inhibitory effect by blocking the MPTP-induced reduction in striatal dopamine content and the number of nigral tyrosine hydroxylase-positive cells. Western blot analysis showed that 1-Me-N-propargyl-TIQ and 1-Me-N-butynyl-TIQ potently prevented the MPTP-induced decrease in dopamine transporter expression, whereas 1-MeTIQ and 1-Me-N-propyl-TIQ did not. These results suggest that although loading an N-propargyl group on 1-MeTIQ clearly enhanced neuroprotective effects, other N-functional groups showed distinct pharmacological properties characteristic of their functional groups. Thus, the number of bonds and length of the N-functional group may contribute to the observed differences in effect.

Neuroprotective effects of Tongtian oral liquid, a Traditional Chinese Medicine in the Parkinson's disease-induced zebrafish model.

Traditional Chinese medicine (TCM) is used in the treatment of Parkinson's disease (PD) worldwide. Tongtian Oral Liquid (TTKFY) is one such patented TCM, and a poly-herbal formulation, composed of 11 herbal constituents, which possess neuroprotective, antioxidant, pain-relieving properties. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP), a neurotoxicant is used to induce PD in animal models. The present study was aimed to evaluate the neuroprotective effects of TTKFY, on dopaminergic neuron development, antioxidant activities, and gene expression involved in the dopaminergic pathway in the MPTP-treated zebrafish model. Zebrafish larvae were treated with MPTP (70 µM) to induce PD and then by different concentrations (0.5, 1, 2, 4 ml/L) of TTKFY. Transgenic zebrafish Vmat: GFP at 5 dpf were used to observe the development of dopaminergic neurons. The activities of T-Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malonaldehyde (MDA) and mRNA gene expression of dopamine pathway were quantified. MPTP-treated zebrafish larvae showed degeneration of dopaminergic neurons, locomotion dysfunction, diminished activities of antioxidant enzymes, MDA accumulation, and altered gene expression of dopamine pathway. In contrast, TTKFY protected dopaminergic neurons, ameliorated behavioral impairments, antioxidant activities and mRNA gene expression of dopamine pathway in a dose-dependent manner. Thus, TTKFY confers protective effects against MPTP-induced neurotoxicity and the mechanisms of protection may be related to the recovery of dopaminergic neurons by reducing oxidative stress via restoring cellular defense mechanisms and thereby highlighting its therapeutic potential to prevent the progression of PD. Further studies are necessary to elucidate the mechanism of action of TTKFY on neuroprotection in the MPTP-induced PD model.

Chicoric Acid Prevents Neuroinflammation and Neurodegeneration in a Mouse Parkinson's Disease Model: Immune Response and Transcriptome Profile of the Spleen and Colon.

Chicoric acid (CA), a polyphenolic acid compound extracted from chicory and echinacea, possesses antiviral, antioxidative and anti-inflammatory activities. Growing evidence supports the pivotal roles of brain-spleen and brain-gut axes in neurodegenerative diseases, including Parkinson's disease (PD), and the immune response of the spleen and colon is always the active participant in the pathogenesis and development of PD. In this study, we observe that CA prevented dopaminergic neuronal lesions, motor deficits and glial activation in PD mice, along with the increment in striatal brain-derived neurotrophic factor (BDNF), dopamine (DA) and 5-hydroxyindoleacetic acid (5-HT). Furthermore, CA reversed the level of interleukin-17(IL-17), interferon-gamma (IFN-γ) and transforming growth factor-beta (TGF-ß) of PD mice, implicating its regulatory effect on the immunological response of spleen and colon. Transcriptome analysis revealed that 22 genes in the spleen (21 upregulated and 1 downregulated) and 306 genes (190 upregulated and 116 downregulated) in the colon were significantly differentially expressed in CA-pretreated mice. These genes were functionally annotated with GSEA, GO and KEGG pathway enrichment, providing the potential target genes and molecular biological mechanisms for the modulation of CA on the spleen and gut in PD. Remarkably, CA restored some gene expressions to normal level. Our results highlighted that the neuroprotection of CA might be associated with the manipulation of CA on brain-spleen and brain-gut axes in PD.

Urolithin A promotes mitophagy and suppresses NLRP3 inflammasome activation in lipopolysaccharide-induced BV2 microglial cells and MPTP-induced Parkinson's disease model.

Microglia-mediated neuroinflammation and mitochondrial dysfunction play critical role in the pathogenic process of Parkinson's disease (PD). Mitophagy plays central role in mitochondrial quality control. Hence, regulation of microglial activation through mitophagy could be a valuable strategy in controlling microglia-mediated neurodegeneration and neuroinflammation. Urolithin A (UA) is a natural compound produced by gut bacteria from ingested ellagitannins (ETs) and ellagic acid (EA). Several preclinical studies have reported the beneficial effects of UA on age-related conditions by increasing mitophagy and blunting excessive inflammatory responses. However, the specific role of UA in pathology of PD remains unknown. In this study, we showed that treatment with UA reduced the loss of dopaminergic neurons, ameliorated behavioral deficits and neuroinflammation in MPTP mouse model of PD. Further study revealed that UA promotes mitophagy, restores mitochondrial function and attenuate proinflammatory response in BV2 microglial cells exposed to LPS. Moreover, UA also reduced NLRP3 inflammasome activation both in vitro and in vivo. Importantly, disruption of microglial mitophagy with pharmacological or genetic approach partly blunted the neuroprotective effects of UA in MPTP mouse model of PD. Collectively, these results provide strong evidence that UA protects against dopaminergic neurodegeneration and neuroinflammation. The mechanism may be related with its inhibition of NLRP3 inflammasome activation via promoting mitophagy in microglia.

3-Pyridinylboronic acid normalizes the effects of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine exposure in zebrafish embryos.

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that damages dopaminergic neurons. Zebrafish has been shown to be a suitable model organism to investigate the molecular pathways in the pathogenesis of Parkinson's disease and also for potential therapeutic agent research. Boron has been shown to play an important role in the neural activity of the brain. Boronic acids are used in combinatorial approaches in drug design and discovery. The effect of 3-pyridinylboronic acid which is an important sub-class of heterocyclic boronic acids has not been evaluated in case of MPTP exposure in zebrafish embryos. Accordingly, this study was designed to investigate the effects of 3-pyridinylboronic acid on MPTP exposed zebrafish embryos focusing on the molecular pathways related to neurodegeneration and apoptosis by RT-PCR. Zebrafish embryos were exposed to MPTP (800 µM); MPTP + Low Dose 3-Pyridinylboronic acid (50 µM) (MPTP + LB) and MPTP + High Dose 3-Pyridinylboronic acid (100 µM) (MPTP + HB) in well plates for 72 hours post fertilization. Results of our study showed that MPTP induced a P53 dependent and Bax mediated apoptosis in zebrafish embryos and 3-pyridinylboronic acid restored the locomotor activity and gene expressions related to mitochondrial dysfunction and oxidative stress due to the deleterious effects of MPTP, in a dose-dependent manner.

Morphine attenuates neurotoxic effects of MPTP in zebrafish embryos by regulating oxidant/antioxidant balance and acetylcholinesterase activity.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases due to the loss of dopaminergic neurons in the midbrain in the substantia nigra. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxic agent causing disruptions in mitochondria of dopaminergic neurons leading to impaired oxidant-antioxidant balance. Both zebrafish and zebrafish embryos are sensitive to MPTP. In zebrafish embryos, MPTP decreases the dopaminergic cells in the diencephalon by damaging dopaminergic neurons. Morphine is an opioid pain killer and a strong analgesic that is used to treat chronic pain. Until today morphine has been shown to regulate the survival or death of neurons and both protective and destructive effects of morphine have been reported in the central nervous system. This study aimed to evaluate the effects of morphine in MPTP-exposed zebrafish embryos. Developmental parameters were monitored and documented daily during embryonic development. Locomotor activity of zebrafish embryos at 96 h postfertilization (hpf) was determined. Acetylcholinesterase (AChE) activity and oxidant-antioxidant parameters were analyzed by biochemical methods. RT-PCR was used to evaluate bdnf, dj1, lrrk and pink1 expressions. Morphine treatment improved mortality and hatching rates, locomotor activity, AChE, and antioxidant enzyme activities as well as the expressions of bdnf, dj1, lrrk and pink1 in a dose-dependent manner that were altered by MPTP. Increased lipid peroxidation supports the role of morphine to induce autophagy to prevent PD-related pathologies. Our study provided important data on the possible molecular mechanism of the therapeutic effects of morphine in PD.

Protective Effect of Isopulegol in Alleviating Neuroinflammation in Lipopolysaccharide-Induced BV-2 Cells and in Parkinson Disease Model Induced with MPTP.

BACKGROUND: Parkinson's disease (PD) is the most prevalent disease linked with age-associated neuronal degeneration. Phytotherapeutic compounds or agents have gained increased importance because of their increased specificity and minimal side effects. Isopulegol, a monoterpene, was utilized in the present study because of its wide range of therapeutic properties. Our aim was to examine the underlying mechanism of anti-neuroinflammatory action and neuroprotective efficacy of isopulegol in cell lines and in an experimental animal model of PD. METHODS: The MTT assay was performed in microglial BV-2 cells subjected to lipopolysaccharides (LPS). The release of NO and synthesis of ROS intracellularly in BV-2 cells were detected. C57BL/6 mice induced with MPTP were examined for motor function and coordination. Expression of proinflammatory mediators was also assessed both in vivo and in vitro. Histopathological sections of brain and expression of iNOS and COX-2 were also analyzed. RESULTS: BV-2 cells did not exhibit noticeable toxicity at selected concentrations and LPS-incubated cells showed marked elevation of NO levels and increased production of intracellular ROS. Increased expression of proinflammatory cytokines was also observed. Motor function and coordination deficits were observed in mice induced with MPTP. Histopathological abnormalities and increased iNOS and COX-2 expression were noted in MPTP-induced mice. Administration of isopulegol reversed the changes brought about by LPS and MPTP. CONCLUSION: The study indicated that isopulegol is a potential therapeutic drug against clinical complications of PD.