Oleanolic Acid enhances the beneficial effects of preconditioning on PC12 cells

Therapeutic Potential of Polyscias fruticosa (L.) Harms Leaf Extract for Parkinson's Disease Treatment by Drosophila melanogaster Model

Parkinson's disease (PD) is characterized by progressive locomotive defects and loss of dopaminergic neurons. Polyscias fruticosa leaves are used by Vietnamese as herbal medicines to support the treatment of some diseases related to neurodegeneration such as Parkinson's and Alzheimer's diseases. However, recent scientific data have not provided sufficient evidence for the use of P. fruticosa leaves to treat PD or decelerate PD progression. In the present study, the capacity of P. fruticosa leaf extract for PD treatment on the dietary supplementation was investigated using dUCH-knockdown Drosophila model. The results indicated that P. fruticosa leaf extract decelerated dopaminergic neuron degeneration induced by dUCH knockdown in not only the larval stage but also the adult stage, which might result in the amelioration in locomotor ability of dUCH-knockdown larvae and flies. Furthermore, antioxidant activities and some key phytochemicals such as saponins, polyphenols, and flavonoids that might contribute to the effects of the P. fruticosa leaf extract were identified.

Protective effects of functional foods against Parkinson's disease: A narrative review on pharmacology, phytochemistry, and molecular mechanisms

In Persian Medicine (PM), PD (brain-based tremor) is a known CNS disorder with several therapeutic and preventive options. In their medical textbooks and pharmacopeias, Persian great scientists such as Rhazes (854-925 AD), Avicenna (980-1037 AD), and Jorjani (1042-1136 AD), have discussed pharmacological and nutritional strategies for the prevention, slowing progression, and treatment of PD. In the present study, we surveyed plant- and animal-based foods recommended by PM for the prevention and treatment of CNS-related tremors. In vivo and in-vitro pharmacological evidence supporting the beneficial effects of PM-recommended foods in prevention and alleviating PD, major active phytochemicals along with the relevant mechanisms of action were studied. Several PM plants possess potent antioxidant, antiinflammatory, and PD preventing properties. Garlic and allicin, cabbage and isothiocyanates, chickpea seed and its O-methylated isoflavones biochanin A and formononetin, cinnamon, and cinnamaldehyde, saffron and its crocin, crocetin, and safranal, black cumin and its thymoquinone, black pepper and piperine, pistachio and genistein and daidzein, and resveratrol are among the most effective dietary itemsagainst PD. They act through attenuating neurotoxin-induced memory loss and behavioral impairment, oxidative stress, and dopaminergic cell death. PM-recommended foods can help alleviate PD progression and also discovering and developing new neuroprotective anti-PD pharmaceuticals.

LncRNA MALAT1 potentiates inflammation disorder in Parkinson's disease

With this investigation, we investigated on the contribution of lncRNA MALAT1 to inflammation disorder in Parkinson's Disease (PD). Serum samples were gathered from sporadic PD patients and healthy controls, and single nucleotide polymorphisms (SNPs) of MALAT1, including rs11227209, rs3200401, rs4102217, rs591291, rs619586 and rs664589, were identified. Serum level of MALAT1 was quantified using RT-PCR, and IL-1β, IL-6, TNF-α and IFN-γ levels in serum were measured with ELISA kits. Inflammation cell models were established by treating PC12 cells with LPS, and cytokine production of pcDNA3.1-MALAT1/si-MALAT1-transfected PC12 cells was evaluated. The results showed that PD patients with high serum level of MALAT1 were associated with lower MMSE score and higher serum levels of IL-1β, IL-6, TNF-α and IFN-γ than patients carrying low serum level of MALAT1 (p < .05). Mutant alleles of SNPs in MALAT1, including rs3200401 (C>T) and rs4102217 (G>C), tended to elevate PD susceptibility and facilitate cytokine production, as compared with their wild alleles (p < .05). And LPS-exposed PC12 cells secreted larger amounts of inflammation cytokines in the pcDNA3.1-MALAT1 group than in the Mock group (p < .05). In conclusion, MALAT1 participated in modifying inflammation disorder underlying PD aetiology, suggesting that it might be a promising therapeutic target for PD.

Oleanolic Acid Mitigates 6-Hydroxydopamine Neurotoxicity by Attenuating Intracellular ROS in PC12 Cells and Striatal Microglial Activation in Rat Brains

Oleanolic acid (OA), a biologically active pentacyclic triterpenoid compound, has been implicated in a number of clinical benefits including antioxidant, and anti-inflammatory properties. OA has been previously shown to ameliorate the toxic effects of 6-hydroxydopamine (6-OHDA), however, the mechanism by which this effect is exhibited is not clearly understood. In the present study, we investigated the role of OA in attenuation of microglial activation in 6-OHDA induced Parkinsonian rat model. We also explored the ability of OA to attenuate 6-OHDA-induced intracellular reactive oxygen species (ROS), and thus prevent cell death in PC12 cells. We accessed the utility of immunohistochemistry to assess striatal microglial activation, where shape descriptors such as area, perimeter, Feret's diameter, aspect ratio and solidity were determined using the Fiji ImageJ software. Intracellular ROS and cell viability were assessed in PC12 cells using the OxiSelect^TM Intracellular ROS Assay Kit and MTT assay, respectively. We found that microglial activation was decreased in rats pre-treated with OA prior to 6-OHDA insult as well as in rats treated with OA 1 day post 6-OHDA exposure when compared to untreated rats, as determined by shape descriptors. This finding was in correlation with significantly improved motor symptoms and increased striatal dopamine in treated rats as compared to non-treated rats. Flow cytometry assessment of PC12 cells revealed a decreased amount of intracellular ROS in cells pre-treated with OA 6 h prior to 6-OHDA exposure and cells treated with OA 1 h post 6-OHDA exposure, suggesting that OA provides neuroprotection in PC12 cells by removing intracellular ROS, thereby reducing oxidative stress. Our finding suggest that OA exhibits its neuroprotective effect by attenuating striatal microglial activation, which results in neuroinflammation that is implicated in Parkinson's disease pathology. Further studies detailing the mechanism by which OA interacts with microglia may be useful in understanding the role of OA in attenuating neuroinflammation.

Conditioning Against the Pathology of Parkinson's disease

Parkinson's disease is delayed in clinical onset, asymmetric in initial appearance, and slow in progression. One explanation for these characteristics may be a boost in natural defenses after early exposure to mild cellular stress. As the patient ages and resilience recedes, however, stress levels may become sufficiently high that toxic cellular responses can no longer be curbed, culminating in inverted U-shaped stress-response curves as a function of disease duration. If dopaminergic systems are indeed capable of responding to mild stress with effective natural defenses, experimental models of Parkinson's disease should adhere to the principles of preconditioning, whereby stress exposure fortifies cells and tempers the toxic sequelae of subsequent stressors. Here, I review evidence favoring the efficacy of preconditioning in dopaminergic systems. Recent animal work also raises the possibility that cross-hemispheric preconditioning may arrest the spread of asymmetric Parkinson's pathology to the other side of the brain. Indeed, compensatory homeostatic systems have long been hypothesized to maintain neurological function until a threshold of cell loss is exceeded and are often displayed as inverted U-shaped curves. However, some stress responses assume an exponential or sigmoidal profile as a function of disease severity, suggesting end-stage deceleration of disease processes. Thus, surviving dopaminergic neurons may become progressively harder to kill, with the dorsal nigral tier dying slower due to superior baseline defenses, inducible conditioning capacity, or delayed dorsomedial nigral spread of disease. In addition, compensatory processes may be useful as biomarkers to distinguish "responder patients" from "nonresponders" before clinical trials. However, another possibility is that defenses are already maximally conditioned in most patients and no further boost is possible. A third alternative is that genuinely diseased human cells cannot be conditioned, in contrast to preclinical models, none of which faithfully recapitulate age-related human conditions. Disease-related "conditioning deficiencies" would then explain how Parkinson's pathology takes root, progressively shrinks defenses, and eventually kills the patient.

Dietary Phytochemicals and Cancer Chemoprevention: A Perspective on Oxidative Stress, Inflammation, and Epigenetics

Oxidative stress occurs when cellular reactive oxygen species levels exceed the self-antioxidant capacity of the body. Oxidative stress induces many pathological changes, including inflammation and cancer. Chronic inflammation is believed to be strongly associated with the major stages of carcinogenesis. The nuclear factor erythroid 2-related factor 2 (Nrf2) pathway plays a crucial role in regulating oxidative stress and inflammation by manipulating key antioxidant and detoxification enzyme genes via the antioxidant response element. Many dietary phytochemicals with cancer chemopreventive properties, such as polyphenols, isothiocyanates, and triterpenoids, exert antioxidant and anti-inflammatory functions by activating the Nrf2 pathway. Furthermore, epigenetic changes, including DNA methylation, histone post-translational modifications, and miRNA-mediated post-transcriptional alterations, also lead to various carcinogenesis processes by suppressing cancer repressor gene transcription. Using epigenetic research tools, including next-generation sequencing technologies, many dietary phytochemicals are shown to modify and reverse aberrant epigenetic/epigenome changes, potentially leading to cancer prevention/treatment. Thus, the beneficial effects of dietary phytochemicals on cancer development warrant further investigation to provide additional impetus for clinical translational studies.

Oleanolic Acid Inhibits High Salt-Induced Exaggeration of Warburg-like Metabolism in Breast Cancer Cells

Cancer cells have a proliferative advantage by utilizing intermediates of aerobic glycolysis (Warburg effect) for their macromolecule synthesis. Although the exact causes of this Warburg effect are unclear, high osmotic stress in solid tumor microenvironment is considered one of the important factors. Oleanolic acid (OA) is known to exert anti-inflammatory and anti-cancer effect. In our current studies, using breast cancer cell lines, we determined the protective role of OA in high salt-mediated osmotic stress-induced cancer growth. Hypertonic (0.16 M NaCl) culture conditions enhanced the cancer cell growth (26 %, p < 0.05) and aerobic glycolysis as marked by increased glucose consumption (34 %, p < 0.05) and lactate production (25 %, p < 0.05) over untreated cells. This effect was associated with increased expression and activity of key rate-limiting enzymes of aerobic glycolysis, namely hexokinase, pyruvate kinase type M2, and lactate dehydrogenase A. Interestingly, this high salt-mediated enhanced expression of aerobic glycolytic enzymes was efficiently reversed by OA along with the decreased cancer cell proliferation. In cancer cells, enhanced aerobic glycolysis is associated with the decreased mitochondrial activity and mitochondrial-associated caspase activity. As expected, high salt further inhibited the mitochondrial related cytochrome oxidase and caspase-3 activity. However, OA efficiently reversed the high salt-mediated inhibition of cytochrome oxidase, caspase activity, and pro-apoptotic Bax expression, thus suggesting that OA induced mitochondrial activity and enhanced apoptosis. Taken together, our data indicate that OA efficiently reverses the enhanced Warburg-like metabolism induced by high salt-mediated osmotic stress along with potential application of OA in anti-cancer therapy.

Natural compound-derived epigenetic regulators targeting epigenetic readers, writers and erasers

Post-translational modifications can affect gene expression in a long-term manner without changes in the primary nucleotide sequence of the DNA. These epigenetic alterations involve dynamic processes that occur in histones, chromatin-associated proteins and DNA. In response to environmental stimuli, abnormal epigenetic alterations cause disorders in the cell cycle, apoptosis and other cellular processes and thus contribute to the incidence of diverse diseases, including cancers. In this review, we will summarize recent studies focusing on certain epigenetic readers, writers, and erasers associated with cancer development and how newly discovered natural compounds and their derivatives could interact with these targets. These advances provide insights into epigenetic alterations in cancers and the potential utility of these alterations as therapeutic targets for the future development of chemopreventive and chemotherapeutic drugs.

Amelioration of L-Dopa-Associated Dyskinesias with Triterpenoic Acid in a Parkinsonian Rat Model

Levo-Dopa (L-Dopa) is widely used for the oral treatment of Parkinson's disease. However, chronic treatment with L-Dopa produces abnormal involuntary movements (AIMs) known as dyskinesias. In this study, commercially available oleanolic acid (OA) that has been previously shown to ameliorate the toxic effects of 6-hydroxydopamine (6-OHDA) in preconditioning studies was used to treat AIMs in a rat model for Parkinson's disease. The forelimb-use asymmetry test was used to measure Parkinson's disease-associated motor impairment. AIMs were measured after 21 days of L-Dopa administration. Glutathione levels were measured in blood, and catalase levels were measured in the substantia nigra and striatum of both the left and right hemispheres. We found that L-Dopa alone as well as L-Dopa and OA combination treatment attenuated the limb-use asymmetry caused by the unilateral injection of 6-OHDA. Chronic L-Dopa administration produced AIMs which were attenuated by treatment with OA. Catalase concentration decreased significantly in the striatum but not in the substantia nigra of the lesioned hemisphere. L-Dopa alone as well as the combined L-Dopa and OA treatment ameliorated the effects of 6-OHDA on catalase concentration. However, intervention with L-Dopa alone as well as with L-Dopa and OA did not affect plasma glutathione concentration. These results suggest that OA administration enhances the effect of catalase on reactive oxygen species following 6-OHDA injection. OA may provide possibilities as an adjunct treatment to prevent or attenuate the development of AIMs following chronic L-Dopa treatment in Parkinson's disease.