Kurarinone alleviated Parkinson's disease via stabilization of epoxyeicosatrienoic acids in animal model.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders and is characterized by loss of dopaminergic neurons in the substantia nigra (SN), causing bradykinesia and rest tremors. Although the molecular mechanism of PD is still not fully understood, neuroinflammation has a key role in the damage of dopaminergic neurons. Herein, we found that kurarinone, a unique natural product from Sophora flavescens, alleviated the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced behavioral deficits and dopaminergic neurotoxicity, including the losses of neurotransmitters and tyrosine hydroxylase (TH)-positive cells (SN and striatum [STR]). Furthermore, kurarinone attenuated the MPTP-mediated neuroinflammation via suppressing the activation of microglia involved in the nuclear factor kappa B signaling pathway. The proteomics result of the solvent-induced protein precipitation and thermal proteome profiling suggest that the soluble epoxide hydrolase (sEH) enzyme, which is associated with the neuroinflammation of PD, is a promising target of kurarinone. This is supported by the increase of plasma epoxyeicosatrienoic acids (sEH substrates) and the decrease of dihydroxyeicosatrienoic acids (sEH products), and the results of in vitro inhibition kinetics, surface plasmon resonance, and cocrystallization of kurarinone with sEH revealed that this natural compound is an uncompetitive inhibitor. In addition, sEH knockout (KO) attenuated the progression of PD, and sEH KO plus kurarinone did not further reduce the protection of PD in MPTP-induced PD mice. These findings suggest that kurarinone could be a potential natural candidate for the treatment of PD, possibly through sEH inhibition.

LRRK2 kinase inhibition protects against Parkinson's disease-associated environmental toxicants.

Idiopathic Parkinson's disease (PD) is epidemiologically linked with exposure to toxicants such as pesticides and solvents, which comprise a wide array of chemicals that pollute our environment. While most are structurally distinct, a common cellular target for their toxicity is mitochondrial dysfunction, a key pathological trigger involved in the selective vulnerability of dopaminergic neurons. We and others have shown that environmental mitochondrial toxicants such as the pesticides rotenone and paraquat, and the organic solvent trichloroethylene (TCE) appear to be influenced by the protein LRRK2, a genetic risk factor for PD. As LRRK2 mediates vesicular trafficking and influences endolysosomal function, we postulated that LRRK2 kinase activity may inhibit the autophagic removal of toxicant damaged mitochondria, resulting in elevated oxidative stress. Conversely, we suspected that inhibition of LRRK2, which has been shown to be protective against dopaminergic neurodegeneration caused by mitochondrial toxicants, would reduce the intracellular production of reactive oxygen species (ROS) and prevent mitochondrial toxicity from inducing cell death. To do this, we tested in vitro if genetic or pharmacologic inhibition of LRRK2 (MLi2) protected against ROS caused by four toxicants associated with PD risk - rotenone, paraquat, TCE, and tetrachloroethylene (PERC). In parallel, we assessed if LRRK2 inhibition with MLi2 could protect against TCE-induced toxicity in vivo, in a follow up study from our observation that TCE elevated LRRK2 kinase activity in the nigrostriatal tract of rats prior to dopaminergic neurodegeneration. We found that LRRK2 inhibition blocked toxicant-induced ROS and promoted mitophagy in vitro, and protected against dopaminergic neurodegeneration, neuroinflammation, and mitochondrial damage caused by TCE in vivo. We also found that cells with the LRRK2 G2019S mutation displayed exacerbated levels of toxicant induced ROS, but this was ameliorated by LRRK2 inhibition with MLi2. Collectively, these data support a role for LRRK2 in toxicant-induced mitochondrial dysfunction linked to PD risk through oxidative stress and the autophagic removal of damaged mitochondria.

Flavonoid intake and risk of Parkinson's disease.

BACKGROUND: Flavonoids have been proposed to reduce the risk of Parkinson's disease (PD). However, results from epidemiological studies have been inconclusive. OBJECTIVE: To prospectively examine the association between the intake of flavonoids and their subclasses and the risk of PD and how pesticides may confound or modify that association. METHODS: The study population comprised 80 701 women (1984-2016) and 48 782 men (1986-2016) from two large US cohorts. Flavonoid intake was ascertained at baseline and every 4 years thereafter using a semiquantitative Food Frequency Questionnaire. We conducted multivariable-adjusted Cox regression models to estimate HRs and 95% CIs of PD according to quintiles of baseline and cumulative average intakes of flavonoids and subclasses. We repeated the analyses, adjusting for intakes of high-pesticide-residue fruits and vegetables (FVs) and stratifying by servings/day of high-pesticide-residue FV intake. RESULTS: We identified 676 incident PD cases in women and 714 in men after 30-32 years of follow-up. Higher total flavonoid intake at baseline was not associated with a lower PD risk, neither in men (HR comparing highest to lowest quintile: 0.89, 95% CI: 0.69 to 1.14) nor in women (HR comparing highest to lowest quintile: 1.27, 95% CI: 0.98 to 1.64). Similar results were observed for cumulative average intakes and flavonoid subclasses. Results remained similar after adjustment for and stratification by high-pesticide-residue FV and when analyses were restricted to younger PD cases. CONCLUSION: These results do not support a protective effect of flavonoid intake on PD risk. Pesticide residues do not confound or modify the association.

The potential of Rhein's aromatic amines for Parkinson's disease prevention and treatment: α-Synuclein aggregation inhibition and disaggregation of preformed fibers.

The aggregation of α-Syn is a pivotal mechanism in Parkinson's disease (PD). Effectively maintaining α-Syn proteostasis involves both inhibiting its aggregation and promoting disaggregation. In this study, we developed a series of aromatic amide derivatives based on Rhein. Two of these compounds, 4,5-dihydroxy-N-(3-hydroxyphenyl)-9,10-dioxo-9,10-dihydroanthracene-2-carboxamide (a5) and 4,5-dihydroxy-N-(2-hydroxy-4-chlorophenyl)-9,10-dioxo-9,10-dihydroanthracene-2-carboxamide (a8), exhibited good binding affinities to α-Syn residues, demonstrating promising inhibitory activity against α-Syn aggregation in vitro, with low IC50 values (1.35 and 1.08 µM, respectivly). These inhibitors acted throughout the entire aggregation process by stabilizing α-Syn's conformation and preventing the formation of ß-sheet aggregates. They also effectively disassembled preformed α-Syn oligomers and fibrils. Preliminary mechanistic insights indicated that they bound to the specific domain within fibrils, inducing fibril instability, collapse, and the formation of smaller aggregates and monomeric α-Syn units. This research underscores the therapeutic potential of Rhein's aromatic amides in targeting α-Syn aggregation for PD treatment and suggests broader applications in managing and preventing neurodegenerative diseases.

Vitamin C, vitamin E, ß-carotene and risk of Parkinson's disease: a systematic review and dose-response meta-analysis of observational studies.

OBJECTIVE: This study aimed to explore the relationship between the intake of vitamin C, vitamin E and ß-carotene, and the risk of Parkinson's disease (PD). METHODS: Web of Science, Embase, PubMed, Cochrane library, CNKI, and WanFang databases were searched from inception to 29 August 2022 for observational studies reporting the odds ratios (ORs) or relative risks (RRs) or hazard ratios (HRs) and 95% confidence intervals (CIs) of PD by Vitamin C/Vitamin E/ß-carotene intake. Random-effects models, publication bias assessment, subgroup, sensitivity and dose-response analyses were performed, using.Stata version 12.0. RESULTS: A total of 13 studies were included. There was no significant association between high-dose vitamin C intake and the risk of PD compared with low-dose vitamin C intake (RR = 0.98, 95%CI:0.89,1.08). Compared with low-dose intake, high-dose intake of vitamin E can prevent the risk of PD (RR = 0.87, 95%CI:0.77,0.99). Compared with lower ß-carotene intake, there was a borderline non-significant correlation between higher intake and PD risk (RR = 0.91, 95%CI:0.82,1.01), and high dose ß-carotene intake was found to be associated with a lower risk of PD in women (RR = 0.78, 95%CI:0.64,0.96). CONCLUSION: This study shows that vitamin E intake can reduce the risk of PD and play a preventive role.

Nutrigenomics in Parkinson's disease: diversity of modulatory actions of polyphenols on epigenetic effects induced by toxins.

Although the pathogenesis of Parkinson's Disease (PD) is not completely understood, there is a consensus that it can be caused by multifactorial mechanisms involving genetic susceptibility, epigenetic modifications induced by toxins and mitochondrial dysfunction. In the past 20 years, great efforts have been made in order to clarify molecular mechanisms that are risk factors for this disease, as well as to identify bioactive agents for prevention and slowing down of its progression. Nutraceutical products have received substantial interest due to their nutritional, safe and therapeutic effects on several chronic diseases. The aim of this review was to gather the main evidence of the epigenetic mechanisms involved in the neuroprotective effects of phenolic compounds currently under investigation for the treatment of toxin-induced PD. These studies confirm that the neuroprotective actions of polyphenols involve complex epigenetic modulations, demonstrating that the intake of these natural compounds can be a promising, low-cost, pharmacogenomic strategy against the development of PD.

A novel treatment strategy to prevent Parkinson's disease: focus on iron regulatory protein 1 (IRP1).

We propose that neural damage in Parkinson's disease (PD) is due to dysregulation of iron utilization rather than to high iron levels per se. Iron deposits are associated with neuronal cell death in substantia nigra (SN) resulting in PD where high levels of iron in SNs are due to dysregulation of iron utilization. Cytosolic aconitase (ACO1) upon losing an iron-sulfur cluster becomes iron regulatory protein 1 (IRP1). Rotenone increases levels of IRP1 and induces PD in rats. An increase in iron leads to inactivation of IRP1. We propose a novel treatment strategy to prevent PD. Specifically in rats given rotenone by subcutaneous injections, iron, from iron carbonyl from which iron is slowly absorbed, given three times a day by gavage will keep iron levels constant in the gut whereby iron levels and iron utilization systematically can be tightly regulated. Rotenone adversely affects complex 1 iron-sulfur proteins. Iron supplementation will increase iron-sulfur cluster formation switching IRP1 to ACO1. With IRP1 levels kept constantly low, iron utilization will systematically be tightly regulated stopping dysregulation of complex 1 and the neural damage done by rotenone preventing PD.

Glutathione-Mediated Neuroprotective Effect of Purine Derivatives.

Numerous basic studies have reported on the neuroprotective properties of several purine derivatives such as caffeine and uric acid (UA). Epidemiological studies have also shown the inverse association of appropriate caffeine intake or serum urate levels with neurodegenerative diseases such as Alzheimer disease (AD) and Parkinson's disease (PD). The well-established neuroprotective mechanisms of caffeine and UA involve adenosine A2A receptor antagonism and antioxidant activity, respectively. Our recent study found that another purine derivative, paraxanthine, has neuroprotective effects similar to those of caffeine and UA. These purine derivatives can promote neuronal cysteine uptake through excitatory amino acid carrier protein 1 (EAAC1) to increase neuronal glutathione (GSH) levels in the brain. This review summarizes the GSH-mediated neuroprotective effects of purine derivatives. Considering the fact that GSH depletion is a manifestation in the brains of AD and PD patients, administration of purine derivatives may be a new therapeutic approach to prevent or delay the onset of these neurodegenerative diseases.

A Stearoyl-Coenzyme A Desaturase Inhibitor Prevents Multiple Parkinson Disease Phenotypes in α-Synuclein Mice.

OBJECTIVE: Parkinson disease (PD) has useful symptomatic treatments that do not slow the neurodegenerative process, and no significant disease-modifying treatments are approved. A key therapeutic target in PD is α-synuclein (αS), which is both genetically implicated and accumulates in Lewy bodies rich in vesicles and other lipid membranes. Reestablishing αS homeostasis is a central goal in PD. Based on previous lipidomic analyses, we conducted a mouse trial of a stearoyl-coenzyme A desaturase (SCD) inhibitor ("5b") that prevented αS-positive vesicular inclusions and cytotoxicity in cultured human neurons. METHODS: Oral dosing and brain activity of 5b were established in nontransgenic mice. 5b in drinking water was given to mice expressing wild-type human αS (WT) or an amplified familial PD αS mutation (E35K + E46K + E61K ["3K"]) beginning near the onset of nigral and cortical neurodegeneration and the robust PD-like motor syndrome in 3K. Motor phenotypes, brain cytopathology, and SCD-related lipid changes were quantified in 5b- versus placebo-treated mice. Outcomes were compared to effects of crossing 3K to SCD1-/- mice. RESULTS: 5b treatment reduced αS hyperphosphorylation in E46K-expressing human neurons, in 3K neural cultures, and in both WT and 3K αS mice. 5b prevented subtle gait deficits in WT αS mice and the PD-like resting tremor and progressive motor decline of 3K αS mice. 5b also increased αS tetramers and reduced proteinase K-resistant lipid-rich aggregates. Similar benefits accrued from genetically deleting 1 SCD allele, providing target validation. INTERPRETATION: Prolonged reduction of brain SCD activity prevented PD-like neuropathology in multiple PD models. Thus, an orally available SCD inhibitor potently ameliorates PD phenotypes, positioning this approach to treat human α-synucleinopathies. ANN NEUROL 2021;89:74-90.

Tauroursodeoxycholic acid (TUDCA) is neuroprotective in a chronic mouse model of Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a progressive motor disease of unknown etiology. Although neuroprotective ability of endogenous bile acid, tauroursodeoxycholic acid (TUDCA), shown in various diseases, including an acute model of PD,the potential therapeutic role of TUDCA in progressive models of PD that exhibit all aspects of PD has not been elucidated. In the present study, mice were assigned to one of four treatment groups: (1) Probenecid (PROB); (2) TUDCA, (3) MPTP + PROB (MPTPp); and (3) TUDCA + MPTPp. Methods: Markers for dopaminergic function, neuroinflammation, oxidative stress and autophagy were assessed using high performance liquid chromatography (HPLC), immunohistochemistry (IHC) and western blot (WB) methods. Locomotion was measured before and after treatments. Results: MPTPp decreased the expression of dopamine transporters (DAT) and tyrosine hydroxylase (TH), indicating dopaminergic damage, and induced microglial and astroglial activation as demonstrated by IHC analysis. MPTPp also decreased DA and its metabolites as demonstrated by HPLC analysis. Further, MPTPp-induced protein oxidation; increased LAMP-1 expression indicated autophagy and the promotion of alpha-synuclein (α-SYN) aggregation. Discussion: Pretreatment with TUDCA protected against dopaminergic neuronal damage, prevented the microglial and astroglial activation, as well as the DA and DOPAC reductions caused by MPTPp. TUDCA by itself did not produce any significant change, with data similar to the negative control group. Pretreatment with TUDCA prevented protein oxidation and autophagy, in addition to inhibiting α-SYN aggregation. Although TUDCA pretreatment did not significantly affect locomotion, only acute treatment effects were measured, indicating more extensive assessments may be necessary to reveal potential therapeutic effects on behavior. Together, these results suggest that autophagy may be involved in the progression of PD and that TUDCA may attenuate these effects. The efficacy of TUDCA as a novel therapy in patients with PD clearly warrants further study.

A focus on natural products for preventing and cure of mitochondrial dysfunction in Parkinson's disease.

Mitochondria are considered the only source of energy production within cells. This organelle is vital for neural function and survival by producing energy (adenosine triphosphate (ATP)) and regulating intracellular calcium. Mitochondrial dysfunction, which significantly contributes to both idiopathic and familial types of Parkinson's disease (PD), depletes cellular energy, disrupts homeostasis, and induces oxidative stress, leading to cell death. In recent years several natural products have been discovered to be protective against mitochondrial dysfunction. This review discusses the role of mitochondria in the progression of PD to define the path for using natural products to prevent and/or cure PD.

Protective effects of prucalopride in MPTP-induced Parkinson's disease mice: Neurochemistry, motor function and gut barrier.

Evidence suggests constipation precedes motor dysfunction and is the most common gastrointestinal symptom in Parkinson's disease (PD). 5-HT4 receptor (5-HT4R) agonist prucalopride has been approved to treat chronic constipation. Here, we reported intraperitoneal injection of prucalopride for 7 days increased dopamine and decreased dopamine turnover. Prucalopride administration improved motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-induced PD mouse models. Prucalopride treatment also ameliorated intestinal barrier impairment and increased IL-6 release in PD model mice. However, prucalopride treatment exerted no impact on JAK2/STAT3 pathway, suggesting that prucalopride may stimulate IL-6 via JAK2/STAT3-independent pathway. In conclusion, prucalopride exerted beneficial effects in MPTP-induced Parkinson's disease mice by attenuating the loss of dopamine, improving motor dysfunction and intestinal barrier.

Evaluating Lipid-Lowering Drug Targets for Parkinson's Disease Prevention with Mendelian Randomization.

Long-term exposure to lipid-lowering drugs might affect Parkinson's disease (PD) risk. We conducted Mendelian randomization analyses where genetic variants indexed expected effects of modulating lipid-lowering drug targets on PD. Statin exposure was not predicted to increase PD risk, although results were not precise enough to support benefits for prevention clearly (odds ratio [OR] = 0.83; 95% confidence interval [CI] = 0.65, 1.07). Other target results were null, except for variants indicating Apolipoprotein-A5 or Apolipoprotein-C3 inhibition might confer protection. These findings suggest peripheral lipid variation may not have a prominent role in PD etiology, but some related drug targets could influence PD via alternate pathways. ANN NEUROL 2020;88:1043-1047.

Two New Zn(II)/Cu(II) Compounds: Photoluminescent and Photocatalytic Properties, and Protective Activity on Parkinson Disease.

Two coordination polymers, that is [Zn(pdc)(im)(H2O)]n (1) and [Cu(pdc)(im)2]n·n(H2pdc) (2) (H2pdc = terephthalic acid, im = imidazole), were hydrothermally synthesized via the reactions of H2pdc and im in combination with Zn(II) or Cu(II) ions. Compound 1 shows intense blue luminescence and compound 2 shows good photocatalytic activity for the methyl violet degradation under the irradiation of ultraviolet light. In addition, the assessment of the two compounds' application values against Parkinson's disease were carried out and their specific mechanism was tested simultaneously. First of all, the real time RT-PCR was implemented and the relative expression levels of N-methyl-D-aspartic acid receptor receptor on neurons were measured. Besides, the Annexin V-FITC/PI apoptosis assay was utilized for the assessment of the influence of the compounds on the dopaminergic neuron death rate. The hemolysis toxicity detection was conducted to detect the biocompatible of the compounds.

Melatonin hormone as a therapeutic weapon against neurodegenerative diseases.

Brain disorders such as Alzheimer's and Parkinson's disease (PD) are irreversible conditions with several cognitive problems, including learning disabilities, memory loss, movement abnormalities, and speech problems. These disorders are caused by a variety of factors, mainly due to the toxic pollutants-induced biochemical changes in protein production, uncontrolled neuronal electrical activity, and altered neurotransmitter levels. Oxidative stress and toxicity associated with the increased glutamate levels decreased acetylcholine levels, and brain inflammation is the main contributing factor. Melatonin hormone is considered one of the potent treatment approaches for neurodegenerative disorders. Melatonin is released from the pineal gland and has a critical role in brain function regulation. Membrane receptors, binding sites, and chemical interaction mediate hormonal actions having multiple phenotypic expressions. It acts as a neurodegenerative agent against some neurological disorders such as Alzheimer's disease (AD), PD, depression, and migraines. Melatonin inhibits neurotoxic pollutants-induced Tau protein hyperphosphorylation, especially in AD. Other pivotal features of melatonin are its anti-inflammatory properties, which decrease pro-inflammatory cytokines expression and factors such as IL-8, IL-6, and TNF. Melatonin also reduces NO (an inflammation factor). In this review, we have highlighted the protective effects of melatonin, mainly spotlighting its neuroprotective mechanisms that will be beneficial to assess their effects in environmental pollution-induced neurodegenerative pathology.

Molecular Hydrogen as a Novel Protective Agent against Pre-Symptomatic Diseases.

Mibyou, or pre-symptomatic diseases, refers to state of health in which a disease is slowly developing within the body yet the symptoms are not apparent. Common examples of mibyou in modern medicine include inflammatory diseases that are caused by chronic inflammation. It is known that chronic inflammation is triggered by the uncontrolled release of proinflammatory cytokines by neutrophils and macrophages in the innate immune system. In a recent study, it was shown that molecular hydrogen (H2) has the ability to treat chronic inflammation by eliminating hydroxyl radicals (·OH), a mitochondrial reactive oxygen species (ROS). In doing so, H2 suppresses oxidative stress, which is implicated in several mechanisms at the root of chronic inflammation, including the activation of NLRP3 inflammasomes. This review explains these mechanisms by which H2 can suppress chronic inflammation and studies its applications as a protective agent against different inflammatory diseases in their pre-symptomatic state. While mibyou cannot be detected nor treated by modern medicine, H2 is able to suppress the pathogenesis of pre-symptomatic diseases, and thus exhibits prospects as a novel protective agent.

pH-Responsive Redox Nanoparticles Protect SH-SY5Y Cells at Lowered pH in a Cellular Model of Parkinson's Disease.

The damage to SH-SY5Y cells by 6-hydroxydopamine (6-OHDA) is an established cellular model of Parkinson's disease (PD). Redox nanoparticles are a promising tool for therapy, including neurodegenerative diseases. As pH of the brain tissue at sites affected by PD is lowered down to 6.5, we studied the effect of pH-responsive redox nanoparticles (poly(ethylene glycol)-b-poly[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)aminomethylstyrene]), which change their structure in a pH-dependent manner and become active below pH 7 (NRNPs pH), on the viability of SH-SY5Y cells treated with 6-OHDA at pH 6.5 and 7.4. Pretreatment of the cells with NRNPs pH (15-75 µM) prior to the 6-OHDA treatment increased their survival in a concentration-dependent manner at pH 6.5, but not at pH 7.4. Among several parameters studied (ATP and GSH content, the level of reactive oxygen species, mitochondrial potential, mitochondrial mass), only the mitochondrial mass was dose-dependently protected by NRNPs pH at pH 6.5, but not at pH 7.4. These results indicate that the action of NRNPs pH on mitochondria underlies their protective effect in this cellular model of PD. These results may have potential importance for future applications of NRNPs pH in preclinical and perhaps clinical studies.

Modifiable risk and protective factors in disease development, progression and clinical subtypes of Parkinson's disease: What do prospective studies suggest?

Parkinson's disease (PD) is a neurodegenerative disorder whose pathogenesis depends on a combination of genetic and environmental factors. The aim of the present review was to provide an updated description of the findings emerging from prospective longitudinal cohort studies on the possible risk/protective factors underlying the development, progression and clinical subtypes of PD. We reviewed all the environmental, lifestyle, dietary, comorbid and pharmacological factors that have been investigated as possible modifiable protective/risk factors for PD by longitudinal studies. Only a few factors have the epidemiological evidence and the biological plausibility to be considered risk (pesticides, dairy products, ß2-adrenoreceptor antagonists) or protective (smoking, caffeine and tea intake, physical activity, gout, vitamin E intake, non-steroidal anti-inflammatory drugs and ß2-adrenoreceptor agonists) factors for PD. Caffeine intake and physical activity also seem to slow down the progression of the disease, thus representing good candidates for primary prevention and disease modifying strategies in PD. Possible modifiable risk factors of PD subtypes is almost unknown and this might depend on the uncertain biological and neuropathological reliability of clinical subtypes. The results of the present review suggest that only eleven risk/protective factors may be associated with the risk of PD. It may be possible to target some of these factors for preventive interventions aimed at reducing the risk of developing and the rate of progression of PD.

Long non-coding RNA NORAD functions as a microRNA-204-5p sponge to repress the progression of Parkinson's disease in vitro by increasing the solute carrier family 5 member 3 expression.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. Long non-coding RNAs have important regulatory values in various human diseases. Non-coding RNA Activated by DNA Damage (NORAD) was reported to regulate PD progression in vitro, but its functional mechanism is fully unknown. We used 1-methyl-4-phenylpyridinium (MPP+ ) to establish the cell-based PD model. NORAD, microRNA-204-5p (miR-204-5p), and solute carrier family 5 member 3 (SLC5A3) levels were quantified using the quantitative real-time polymerase chain reaction. Cell viability and apoptosis were determined by Cell Counting Kit-8 and flow cytometry, respectively. The protein levels were analyzed via western blot. Cytotoxicity was assessed by the released lactate dehydrogenase level in cell supernatant. Oxidative stress and inflammation were measured by the standard indicators. Dual-luciferase reporter and RNA immunoprecipitation assays were performed for intergenic combination. First, we found that NORAD was obviously reduced in MPP+ -treated neuroblastoma cells and lightened the MPP+ -induced cytotoxicity, oxidative stress, and inflammatory response. Then, NORAD was shown to be a miR-204-5p sponge and avoided the injury induced by MPP+ in neuroblastoma cells via targeting miR-204-5p. SLC5A3 was a miR-204-5p target and could be regulated by NORAD/miR-204-5p axis. SLC5A3 knockdown assuaged the anti-miR-204-5p-induced protection for neuroblastoma cells from MPP+ . Altogether, NORAD played a neuroprotective role against the progression of MPP+ -induced PD model in neuroblastoma cells relying on the miR-204-5p/SLC5A3 axis. This study afforded the clear elaboration on the PD pathomechanism concerning NORAD.

The Putative Role of 1,25(OH)2D3 in the Association of Milk Consumption and Parkinson's Disease.

The consumption of dairy products, particularly of low fat milk, has been shown to be associated with the occurrence of Parkinson's disease. This association does not necessarily reflect a pathophysiological role of milk intake in the development of Parkinson's disease. Nevertheless, the present review discusses a potential mechanism possibly mediating an effect of milk consumption on Parkinson's disease. The case is made that milk is tailored in part to support bone mineralization of the suckling offspring and is thus rich in calcium and phosphate. Milk intake is thus expected to enhance intestinal calcium phosphate uptake. As binding to fatty acids impedes Ca2+ absorption, low fat milk is particularly effective. Calcium and phosphate uptake inhibit the formation of 1,25(OH)2D3 (1,25-dihydroxy-vitamin D3 = calcitriol), the active form of vitamin D. Calcium inhibits 1,25(OH)2D3 production in part by suppressing the release of parathyroid hormone, a powerful stimulator of 1,25(OH)2D3 formation. Phosphate excess stimulates the release of fibroblast growth factor FGF23, which suppresses 1,25(OH)2D3 formation, an effect requiring Klotho. 1,25(OH)2D3 is a main regulator of mineral metabolism, but has powerful effects apparently unrelated to mineral metabolism, including suppression of inflammation and influence of multiple brain functions. In mice, lack of 1,25(OH)2D3 and excessive 1,25(OH)2D3 formation have profound effects on several types of behavior, such as explorative behavior, anxiety, grooming and social behavior. 1,25(OH)2D3 is produced in human brain and influences the function of various structures including substantia nigra. In neurons 1,25(OH)2D3 suppresses oxidative stress, inhibits inflammation and stimulates neurotrophin formation thus providing neuroprotection. As a result, 1,25(OH)2D3 is considered to favorably influence the clinical course of Parkinson's disease. In conclusion, consumption of milk could in theory accelerate the downhill course of neuronal function in Parkinson's disease. However, substantial additional experimentation is required to define the putative causal role of 1,25(OH)2D3 in the pathophysiology of Parkinson's disease and its sensitivity to milk consumption.