Squamosamide derivative FLZ protects dopaminergic neurons against inflammation-mediated neurodegeneration through the inhibition of NADPH oxidase activity

<p>Abstract</p> <p>Background</p> <p>Inflammation plays an important role in the pathogenesis of Parkinson's disease (PD) through over-activation of microglia, which consequently causes the excessive production of proinflammatory and neurotoxic factors, and impacts surrounding neurons and eventually induces neurodegeneration. Hence, prevention of microglial over-activation has been shown to be a prime target for the development of therapeutic agents for inflammation-mediated neurodegenerative diseases.</p> <p>Methods</p> <p>For <it>in vitro </it>studies, mesencephalic neuron-glia cultures and reconstituted cultures were used to investigate the molecular mechanism by which FLZ, a squamosamide derivative, mediates anti-inflammatory and neuroprotective effects in both lipopolysaccharide-(LPS)- and 1-methyl-4-phenylpyridinium-(MPP⁺)-mediated models of PD. For <it>in vivo </it>studies, a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine-(MPTP-) induced PD mouse model was used.</p> <p>Results</p> <p>FLZ showed potent efficacy in protecting dopaminergic (DA) neurons against LPS-induced neurotoxicity, as shown in rat and mouse primary mesencephalic neuronal-glial cultures by DA uptake and tyrosine hydroxylase (TH) immunohistochemical results. The neuroprotective effect of FLZ was attributed to a reduction in LPS-induced microglial production of proinflammatory factors such as superoxide, tumor necrosis factor-α (TNF-α), nitric oxide (NO) and prostaglandin E₂(PGE₂). Mechanistic studies revealed that the anti-inflammatory properties of FLZ were mediated through inhibition of NADPH oxidase (PHOX), the key microglial superoxide-producing enzyme. A critical role for PHOX in FLZ-elicited neuroprotection was further supported by the findings that 1) FLZ's protective effect was reduced in cultures from PHOX^-/-mice, and 2) FLZ inhibited LPS-induced translocation of the cytosolic subunit of p47^PHOXto the membrane and thus inhibited the activation of PHOX. The neuroprotective effect of FLZ demonstrated in primary neuronal-glial cultures was further substantiated by an <it>in vivo </it>study, which showed that FLZ significantly protected against MPTP-induced DA neuronal loss, microglial activation and behavioral changes.</p> <p>Conclusion</p> <p>Taken together, our results clearly demonstrate that FLZ is effective in protecting against LPS- and MPTP-induced neurotoxicity, and the mechanism of this protection appears to be due, at least in part, to inhibition of PHOX activity and to prevention of microglial activation.</p

Role of AMPK and PPARα in the anti-skin cancer effects of ursolic acid

The phytonutrient ursolic acid (UA), present in apples, rosemary, and other plant sources, has anti-cancer properties in a number of systems, including skin cancers. However, few reports have examined upstream mechanisms by which UA may prevent or treat cancer. Recent reports have indicated UA induces death of cancer cell lines via AMP-activated protein kinase (AMPK), an energy-sensing kinase which possesses both pro-metabolic and anti-cancer effects. Other studies have shown UA activates peroxisome proliferator activated receptor α (PPARα) and the glucocorticoid receptor (GR). Here, we found the cytotoxic effect of UA in skin carcinoma cells required AMPK activation. In addition, two inhibitors of PPARα partially reversed the cytotoxic effects of UA, suggesting its effects are at least partially mediated through this receptor. Finally, inhibition of the GR did not reverse the effects of UA nor did this compound bind the GR under the conditions of experiments performed. Overall, studies elucidating the anti-cancer effects of UA may allow for the development of more potent analogues utilizing similar mechanisms. These studies may also reveal the mediators of any possible side effects or resistance mechanisms to UA therapy

Inhibition of neddylation represses lipopolysaccharide-induced proinflammatory cytokine production in macrophage cells

Background: Lipopolysaccharides (LPSs) up-regulate proinflammatory cytokines in macrophages, partly through a NF-κB-dependent process. Results: Blocking neddylation, which helps regulate NF-κB, represses LPS-induced up-regulation of proinflammatory cytokines. Conclusion: Neddylation plays a role in the up-regulation of NF-κB-regulated proinflammatory cytokines produced by macrophages in response to LPS. Significance: Inhibition of neddylation represents a novel and effective method for the prevention of LPS-induced proinflammatory cytokines

Predicting serum levels of lithium-treated patients: A supervised machine learning approach

Routine monitoring of lithium levels is common clinical practice. This is because the lithium prediction strategies available developed by previous studies are still limited due to insufficient prediction performance. Thus, we used machine learning approaches to predict lithium concentration in a large real-world dataset. Real-world data from multicenter electronic medical records were used in different machine learning algorithms to predict: (1) whether the serum level was 0.6-1.2 mmol/L or 0.0-0.6 mmol/L (binary prediction), and (2) its concentration value (continuous prediction). We developed models from 1505 samples through 5-fold cross-validation and used 204 independent samples to test their performance by evaluating their accuracy. Moreover, we ranked the most important clinical features in different models and reconstructed three reduced models with fewer clinical features. For binary and continuous predictions, the average accuracy of these models was 0.70-0.73 and 0.68-0.75, respectively. Seven features were listed as important features related to serum lithium levels of 0.6-1.2 mmol/L or higher lithium concentration, namely older age, lower systolic blood pressure, higher daily and last doses of lithium prescription, concomitant psychotropic drugs with valproic acid and -pine drugs, and comorbid substance-related disorders. After reducing the features in the three new predictive models, the binary or continuous models still had an average accuracy of 0.67-0.74. Machine learning processes complex clinical data and provides a potential tool for predicting lithium concentration. This may help in clinical decision-making and reduce the frequency of serum level monitoring

The different catalytic roles of the metal- binding ligands in human 4-hydroxyphenylpyruvate dioxygenase

4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a non-haem iron(II)-dependent oxygenase that catalyses the conversion of 4-hydroxyphenylpyruvate (HPP) to homogentisate (HG). In the active site, a strictly conserved 2-His-1-Glu facial triad co-ordinates the iron ready for catalysis. Substitution of these residues resulted in about a 10-fold decrease in the metal binding affinity, as measured by isothermal titration calorimetry, and a large reduction in enzyme catalytic efficiencies. The present study revealed the vital role of the ligand Glu349 in enzyme function. Replacing this residue with alanine resulted in loss of activity. The E349G variant retained 5% activity for the coupled reaction, suggesting that co-ordinating water may be able to support activation of the trans-bound dioxygen upon substrate binding. The reaction catalysed by the H183A variant was fully uncoupled. H183A variant catalytic activity resulted in protein cleavage between Ile267 and Ala268 and the production of an N-terminal fragment. The H266A variant was able to produce 4-hydroxyphenylacetate (HPA), demonstrating that decarboxylation had occurred but that there was no subsequent product formation. Structural modelling of the variant enzyme with bound dioxygen revealed the rearrangement of the co-ordination environment and the dynamic behaviour of bound dioxygen in the H266A and H183A variants respectively. These models suggest that the residues regulate the geometry of the reactive oxygen intermediate during the oxidation reaction. The mutagenesis and structural simulation studies demonstrate the critical and unique role of each ligand in the function of HPPD, and which correlates with their respective co-ordination position.</jats:p

Zebrafish Cyclin-Dependent Protein Kinase–Like 1 (zcdkl1): Identification and Functional Characterization

The cyclin-dependent protein kinase family regulates a wide range of cellular functions such as cell cycle progression, differentiation, and apoptosis. In this study, we identified a zebrafish cyclin-dependent protein kinase-like 1 protein called zebrafish cdkl1 (zcdkl1), which shared a high degree of homology and conserved synteny with mammalian orthologs. zcdkl1 exhibited abilities for phosphorylation of myelin basic protein and histone H1. RT-PCR analysis revealed that zcdkl1 was expressed starting from fertilization and continuing thereafter. In adult tissues, zcdkl1 was predominantly detected in brain, ovary, and testis, and was expressed at low levels in other tissues. At 50% epiboly stage, zcdkl1 was widely expressed. At 12 to 48 h post-fertilization, zcdkl1 was predominantly expressed in the hypochord, the medial and lateral floor plate, and the pronephric duct. Interference of zcdkl1 expression resulted in abnormalities, such as brain and eye malformation, pericardial edema, and body axis curvature. Disruption of zcdkl1 reduced neurogenin-1 in the brain and sonic hedgehog expression in the floor plate region. These deformities were apparently rescued by co-injection of zcdkl1 mRNA. Findings of this study indicate that zcdkl1 plays an essential role in zebrafish development

Novel Neuroprotective Mechanisms of Memantine: Increase in Neurotrophic Factor Release from Astroglia and Anti-Inflammation by Preventing Microglial Activation

Memantine provides clinically relevant efficacy in patients with Alzheimer's disease and Parkinson’s diseases. In addition to blockade of N-methyl-D-aspartate receptor on neurons, memantine has neurotrophic and neuroprotective effects in in vivo and in vitro studies, however, the mechanism underlying these effects remains unclear. To address this question, primary midbrain neuron-glia cultures and reconstituted cultures were used, and lipopolysaccharide (LPS), an endotoxin from bacteria, was used to produce inflammation-mediated dopaminegic neuronal death. Here, we show that memantine exerted both potent neurotrophic and neuroprotective effects on dopaminergic neurons in rat neuron-glia cultures. The neurotrophic effect of memantine was glia-dependent, since memantine failed to show any positive effect on dopaminergic neurons in neuron-enriched cultures. More specifically, it appears that astroglia, not microglia, are the source of the memantine-elicited neurotrophic effects through the increased production of GDNF. Mechanistic studies revealed that GDNF upregulaton was associated with histone hyperacetylation by inhibiting the cellular histone deacetylase activity. In addition, memantine also displays neuroprotective effects against LPS-induced dopaminergic neuronal damage through its inhibition of microglia over-activation revealed by both OX-42 immunostaining and by the reduction of pro-inflammatory factors production such as extracelluar superoxide anion, intracellular reactive oxygen species, nitric oxide, prostaglandin E2, and tumor necrosis factor-α. These results suggest that memantine therapy for neurodegenerative diseases acts in part through alternative novel mechanisms by reducing microglia-associated inflammation and stimulating the release of neurotrophic factors from astroglia

Patients with chronic periodontitis are more likely to develop upper urinary tract stone: a nation-wide population-based eight-year follow up study

Background The purpose of this study was to investigate the relationship between chronic periodontitis (CP) and upper urinary tract stone (UUTS) in Taiwan by using a population-based data set. Methods A total of 16,292 CP patients and 48,876 randomly-selected controls without chronic periodontitis were selected from the National research database and studied retrospectively. Subjects selected have not been diagnosed with UUTS previously. These subjects were prospectively followed for at least eight years. Cox regression models were used to explore the connection between risk factors and the development of UUTS. Results The CP patients have a greater chance of developing UUTS compared to controls (1761/16292, 10.8% vs. 4775/48876, 9.8%, p-values < 0.001). Conditioned logistic regression suggested CP increases the risk of UUTS development (HR 1.14, 95% CI [1.08–1.20], p < 0.001). After respective adjustment for age, gender, hypertension and diabetes, results showed that CP still increases the risk of developing UUTS (HR 1.14, 95% CI [1.08–1.20], p < 0.001). Conclusion By using a population-based database with a minimum eight 8 follow-up of CP in Taiwan, we discovered patients with CP are more likely to develop UUTS

Corrigendum to “An Emerging Translational Model to Screen Potential Medicinal Plants for Nephrolithiasis, an Independent Risk Factor for Chronic Kidney Disease”

Pharmacological therapy for urolithiasis using medicinal plants has been increasingly adopted for the prevention of its recurrence. A Drosophila melanogaster model developed for translational research of urolithiasis was applied to evaluate agents with potential antilithic effects and calcium oxalate (CaOx) formation. Potential antilithic herbs were prepared in a mixture of food in a diluted concentration of 5,000 from the original extract with 0.5% ethylene glycol (EG) as the lithogenic agent. The control group was fed with food only. After 3 weeks, flies (n≥150 for each group) were killed using CO2 narcotization, and the Malpighian tubules were dissected, removed, and processed for polarized light microscopy examination of the crystals. The crystal formation rate in the EG group was 100.0%. In the study, 16 tested herbal drugs reached the crystal formation rate of 0.0%, including Salviae miltiorrhizae, Paeonia lactiflora, and Carthami flos. Scutellaria baicalensis enhanced CaOx crystal formation. Two herbal drugs Commiphora molmol and Natrii sulfas caused the death of all flies. Our rapid screening methods provided evidence that some medicinal plants have potential antilithic effects. These useful medicinal plants can be further studied using other animal or human models to verify their effects