morroniside and Neuroblastoma

Oxidative stress-induced cell injury has been linked to the pathogenesis of neurodegenerative disorders such as spinal cord injury, Parkinson's disease, and multiple sclerosis. Morroniside is an antioxidant derived from the Chinese herb Shan-Zhu-Yu. The present study investigated the neuroprotective effect of morroniside against hydrogen peroxide (H2O2)-induced cell death in SK-N-SH human neuroblastoma cells. H2O2 increased cell apoptosis, as determined by flow cytometry and Hoechst 33342 staining. This effect was reversed by pretreatment with morroniside at concentrations of 1-100 µM. The increase in intracellular reactive oxygen species (ROS) generation and lipid peroxidation induced by H2O2 was also abrogated by morroniside. H2O2 induced a reduction in mitochondrial membrane potential, increased caspase-3 activity, and caused downregulation of B cell lymphoma-2 (Bcl-2) and upregulation of Bcl-2-associated X protein (Bax) expression. These effects were blocked by morroniside pretreatment. Thus, morroniside protects human neuroblastoma cells against oxidative damage by inhibiting ROS production while suppressing Bax and stimulating Bcl-2 expression, thereby blocking mitochondrial-mediated apoptosis. These results indicate that morroniside has therapeutic potential for the prevention and treatment of neurodegenerative diseases.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Caspase 3; Cell Line, Tumor; Cell Survival; Glycosides; Humans; Hydrogen Peroxide; Lipid Peroxidation; Matrix Metalloproteinases; Membrane Potential, Mitochondrial; Neuroblastoma; Neuroprotective Agents; Oxidants; Oxidative Stress; Reactive Oxygen Species; Superoxide Dismutase

An accumulation of hyperphosphorylated tau in the brain is a hallmark of Alzheimer's disease (AD). Deficits in protein phosphatase 2A (PP2A) are associated with tau hyperphosphorylation in AD.. To investigate the effects of morroniside (MOR), isolated from Cornus officinalis, on tau hyperphosphorylation and its underlying mechanisms related to PP2A.. SK-N-SH cells were pretreated with 50-200 μM MOR for 24 h followed by 20 nM okadaic acid (OA) for 6 h. PP2Ac siRNA was transfected into HEK293 cells to determine the direct interaction of MOR with PP2A. Western blotting was used to measure the expression of proteins and enzymes. PP2A activity was measured by molybdenum blue spectrophotometry.. Pretreatment with MOR improved the cellular morphological damage and inhibited tau hyperphosphorylation in SK-N-SH cells induced by OA, a PP2A inhibitor. Moreover, MOR increased PP2A activity, concurrent with a decrease in the expression of demethylated PP2A at Leu309 and phosphorylated PP2A at Tyr307. MOR decreased protein phosphatase methylesterase 1 (PME-1) expression and the ratio of PME-1/leucine carboxyl methyltransferase 1 (LCMT-1). Furthermore, MOR treatment decreased the phosphorylation of Src at Tyr416, which regulates the phosphorylation of PP2A. MOR had no effect on PP2Ac expression and tau hyperphosphorylation in PP2Ac siRNA-transfected cells.. MOR attenuated OA-induced tau hyperphosphorylation via PP2A activation, and its mechanism might be related to the regulation of PP2Ac post-translational modification and upstream enzymes such as Src and PME-1.

Topics: Analysis of Variance; Cell Line; Enzyme Inhibitors; Gene Expression Regulation; Glycogen Synthase Kinase 3 beta; Glycosides; HEK293 Cells; Humans; Neuroblastoma; Okadaic Acid; Phosphorylation; Protein Phosphatase 2; RNA, Small Interfering; tau Proteins; Transfection; Tyrosine

Oxidative stress-induced cell damage has been implicated in a variety of neurodegenerative disorders. Morroniside, an iridorid glycoside isolated from Cornus officinalis Sieb. Et Zucc., has shown potent antioxidant properties. The present study investigated the protective actions of morroniside against the cytotoxicity produced by exposure to H(2)O(2) (300-500 microM) in SH-SY5Y cells. Intracellular accumulation of Ca(2+), and decreases in mitochondrial membrane potential (MMP) caused by added H(2)O(2) were reduced by morroniside. Incubation of cells with H(2)O(2) caused a marked decrease in superoxide dismutase (SOD) activity; this decrease was significantly inhibited by morroniside. In addition, the percentage of cells undergoing H(2)O(2)-induced apoptosis was decreased, dose dependently, in the presence of morroniside. These results suggest that morroniside has protective effects against oxidative stress-induced neurotoxic processes.

Topics: Animals; Apoptosis; Calcium; Cell Line, Tumor; Cytotoxins; Enzyme Induction; Glycosides; Humans; Hydrogen Peroxide; Intracellular Space; Membrane Potential, Mitochondrial; Neuroblastoma; Superoxide Dismutase

(1) Morroniside belongs to an extensive group of natural iridorid glycosides. In the present study, using human neuroblastoma SH-SY5Y cells, we have investigated the protective effects of this compound on modifications in endogenous reduced glutathione (GSH), intracellular oxygen species (ROS) and apoptotic death on H(2)O(2)-mediated cytoxicity. (2) Incubation of cells with morroniside led to a significant dose-dependent elevation of cellular GSH accompanied by a marked protection against H(2)O(2)-mediated toxicity. Morroniside at 1-100 microM inhibited the formation of ROS and the activation of caspase-3 and 9, and the upregulation of Bcl-2, whereas no significant change occurred in Bax levels. (3) The results indicated that the anti-oxidative and anti-apoptotic properties render this natural compound potentially protective against H(2)O(2)-induced cytotoxicity. (4) This study suggested that intracellular GSH appeared to be an important factor in morroniside-mediated cytoprotection against H(2)O(2)-toxicity in SH-SY5Y cells.

Topics: Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Line, Tumor; Drug Interactions; Drugs, Chinese Herbal; Glutathione; Glycosides; Humans; Hydrogen Peroxide; Neuroblastoma; Neurons; Oxidants; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species