Xin Zhao

Neuroprotective effects of protocatechuic aldehyde against neurotoxin-induced cellular and animal models of Parkinson's disease.

Protocatechuic aldehyde (PAL) has been reported to bind to DJ-1, a key protein involved in Parkinson’s disease (PD), and exerts potential neuroprotective effects via DJ-1 in SH-SY5Y cells. In this study, we investigated the neuroprotective pharmacological effects of PAL against neurotoxin-induced cell and animal models of PD. In cellular models of PD, PAL markedly increased cell viability rates, mitochondrial oxidation-reduction activity and mitochondrial membrane potential, and reduced intracellular ROS levels to prevent neurotoxicity in PC12 cells. In animal models of PD, PAL reduced the apomorphine injection, caused turning in 6-OHDA treated rats, and increased the motor coordination and stride decreases in MPTP treated mice. Meanwhile, in an MPTP mouse model, PAL prevented a decrease of the contents of dopamine (DA) and its metabolites in the striatum and TH-positive dopaminergic neuron loss in the substantia nigra (SN). In addition, PAL increased the protein expression of DJ-1 and reduced the level of α-synuclein in the SN of MPTP lesioned mice. PAL also increased the spine density in hippocampal CA1 neurons. The current study demonstrates that PAL can efficiently protect dopaminergic neurons against neurotoxin injury in vitro and in vivo, and that the potential mechanisms may be related to its effects in increasing DJ-1, decreasing α-synuclein and its growth-promoting effect on spine density.

Two xanthones from Swertia punicea with hepatoprotective activities in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCEnSwertia punicea Hemsl. (Gentianaceae) is more commonly known as Ganyan-cao and used mainly as a traditional Chinese folk medicine for the treatment of acute bilious hepatitis, cholecystitis, fever, intoxification and jaundice.nnnMATERIALS AND METHODSnThe active hepatoprotective constituents of Swertia punicea were purified using various column chromatography techniques. The structures of two isolated compounds were determined on the basis of spectroscopic data interpretation such as NMR analysis. The hepatoprotective activities of isolated compounds were evaluated by using hepatotoxicity in vitro and dimethylnitrosamine-induced rat hepatic fibrosis in vivo, respectively.nnnRESULTSnTwo xanthones, 1, 7-dihydroxy-3, 4, 8-trimethoxyxanthone (1) and bellidifolin (2) were isolated from the stems of Swertia punicea. The compounds 1 and 2 exhibited notable hepatoprotective activities against carbon tetrachloride (CCl4) -induced HepG2 cell damage, and effectively alleviated the levels of aspartate transaminase (AST), lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malonic dialdehyde (MDA) induced by CCl₄ in a concentration-dependent manner. Co-treatment with compound 2 significantly increased the cell viability compared with N-acetyl-p-aminophenol (APAP) treatment. Compound 2 also alleviated APAP-induced hepatotoxicity by increasing glutathione (GSH) content and decreasing hydroxyl free radical (·OH) levels and reactive oxygen specises (ROS) production. In addition, the protective effect of compound 1 significantly alleviated DMN-induced liver inflammation and fibrosis. Oral administration of compound 1 recovered the reduction of albumin (ALB) and reversed the elevation of serum alanine transaminase (ALT), AST and total bilirubin (TBIL) in dimethylnitrosamine (DMN)-induced fibrotic rats. Severe oxidative stress induced in fibrotic rats was evidenced by a 1.5-fold elevation in MDA and a fall in the SOD activity, and treatment with compound 1 protected against these adverse effects. Recovery of rat liver tissue against DMN-induced hepatocellular necrosis, inflammatory changes and hepatic fibrosis by compound 1 is also confirmed by H&E and Masson stained histopathological evaluation of liver tissue.nnnCONCLUSIONnTwo xanthones from Swertia punicea exhibited hepatoprotective activities in vitro (compounds 1 and 2) and in vivo (compound 1), respectively.

3-O-demethylswertipunicoside inhibits MPP+-induced oxidative stress and apoptosis in PC12 cells

The 3-O-demethylswertipunicoside (3-ODS) is extracted from Swertia punicea. Recent study from our laboratory has demonstrated that the 3-ODS protects against oxidative toxicity and apoptosis in PC12 cells (Zhang, S.P., Du, X.G., Pu, X.P., 2010. Biol. Pharm. Bull. 33, 1529-1533). The aim of our study is to further investigate the neuroprotective mechanisms of 3-ODS in 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity in PC12 cells. The results indicated that pre-treatment with 3-ODS significantly increased the cell viability compared with MPP(+) treatment. It also alleviated the oxidative stress by increasing superoxide dismutase (SOD) activity and decreasing malondialdehyde (MDA) level and reactive oxygen specise (ROS) production. Moreover, 3-ODS also attenuated MPP(+)-induced apoptosis by inhibiting Bax and Bcl-2 expressions, activating caspase-9, caspase-3, poly (ADP-ribose) polymerase-1 (PARP-1) cleavage, apoptosis-inducing factor (AIF) translocation and α-synuclein expression. These results suggest that 3-ODS might has applications as a complementary medicine for the treatment of Parkinsons disease (PD) or other neurodegenerative diseases.

PARK7 protein translocating into spermatozoa mitochondria in Chinese asthenozoospermia

PARK7 (DJ1) is a multifunctional oxidative stress response protein that protects cells against reactive oxygen species (ROS) and mitochondrial damage. PARK7 defects are known to cause various physiological dysfunctions, including infertility. Asthenozoospermia (AS), i.e. low-motile spermatozoa in the ejaculate, is a common cause of human male infertility. In this study, we found that downregulation of PARK7 resulted in increased levels of lipid peroxide and ROS, decreased mitochondrial membrane potential, and reduced mitochondrial complex I enzyme activity in the spermatozoa from AS patients. Furthermore, it was observed that PARK7 was translocated into the mitochondria of damaged spermatozoa in AS. Finally, we examined the oxidative state of PARK7 and the results demonstrated the enhancement of oxidation, expressed by increased sulfonic acid residues, the highest form of oxidation, as the sperm motility decreased. Taken together, these results revealed that PARK7 deficiency may increase the oxidative stress damage to spermatozoa. Our present findings open new avenues of therapeutic intervention targeting PARK7 for the treatment of AS.

Serum Proteomic Analysis Reveals High Frequency of Haptoglobin Deficiency and Elevated Thyroxine Level in Heroin Addicts

Heroin addiction is a chronic, complex disease, often accompanied by other concomitant disorders, which may encumber effective prevention and treatment. To explore the differences in expression profiles of serum proteins in control and heroin addicts, we used two-dimensional electrophoresis coupled to MALDI-TOF/TOF, and identified 4 proteins of interest. Following validation of the increase in serum transthyretin, we assessed serum levels of thyroid stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4), and observed a robust increase in T4 in heroin addicts compared to controls. In addition, we performed haptoglobin (Hp) phenotyping, and showed that the frequency of Hp0 (serum devoid of haptoglobin) was significantly higher in heroin addicts. Altogether, these findings indicated that: (1) thyroid hormone imbalance is present in heroin addicts; (2) anhaptoglobinemia (Hp0) might a risk factor or a deleterious effect of heroin abuse.

Expression of the Parkinson's disease protein DJ-1 during the differentiation of neural stem cells

DJ-1 is a key neuroprotective factor and its loss-of-function mutations cause an autosomal recessive, early-onset form of familial Parkinsons disease at the chromosomal PARK7 locus. However, the expression of DJ-1 during the differentiation of neural stem cells has not been fully elucidated. In this study, we investigated the expression of DJ-1 quantitatively using fluorescence immunocytochemistry and flow cytometry for differentiated neural stem cells from the cortex of the 14-day mouse embryos. We found that DJ-1 was co-expressed with the neuron-specific enolase and glial fibrillary acidic proteins, and also its expression was significantly increased in neurons and astrocytes with a prolonged differentiation period. These findings strongly suggest that DJ-1 is closely associated with the differentiation of neural stem cells.

( S )-Oxiracetam is the Active Ingredient in Oxiracetam that Alleviates the Cognitive Impairment Induced by Chronic Cerebral Hypoperfusion in Rats

Chronic cerebral hypoperfusion is a pathological state that is associated with the cognitive impairments in vascular dementia. Oxiracetam is a nootropic drug that is commonly used to treat cognitive deficits of cerebrovascular origins. However, oxiracetam is currently used as a racemic mixture whose effective ingredient has not been identified to date. In this study, we first identified that (S)-oxiracetam, but not (R)-oxiracetam, was the effective ingredient that alleviated the impairments of spatial learning and memory by ameliorating neuron damage and white matter lesions, increasing the cerebral blood flow, and inhibiting astrocyte activation in chronic cerebral hypoperfused rats. Furthermore, using MALDI-MSI and LC-MS/MS, we demonstrated that (S)-oxiracetam regulated ATP metabolism, glutamine-glutamate and anti-oxidants in the cortex region of hypoperfused rats. Altogether, our results strongly suggest that (S)-oxiracetam alone could be a nootropic drug for the treatment of cognitive impairments caused by cerebral hypoperfusion.

Icaritin Provokes Serum Thrombopoietin and Downregulates Thrombopoietin/MPL of the Bone Marrow in a Mouse Model of Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a common acquired autoimmune disease, and thrombopoietin (TPO) is an important cytokine that regulates the production of megakaryocytes and platelets. We have identified a biologically active component, icaritin, from a Chinese herba epimedii extract. Icaritin promotes platelet production and regulates T cell polarization, but its mechanism is not clear. In this study, the BALB/c mouse model of ITP was established by injection of an antiplatelet antibody every other day for seven total times. The antiplatelet sera were derived from guinea pigs immunized with the platelets of BALB/c mice. Mice with ITP were treated with icaritin at low, moderate, or high doses of 4.73, 9.45, and 18.90u2009mg/kg, respectively, for fourteen consecutive days. The present study shows that icaritin can significantly increase peripheral blood platelet counts and thrombocytocrit, increase the TPO level in serum, attenuate splenomegaly, and reduce the abnormal proliferation of megakaryocytes in the spleen and bone marrow. Icaritin can also downregulate the expression of bone marrow TPO, myeloproliferative leukemia virus oncogene (MPL), and p-Stat3. Our results suggest that icaritin can significantly improve the health of mice with ITP via possible downregulation of p-Stat3 expression in the JAK2/Stat3 phosphorylation signaling pathway and regulation of bone marrow TPO/MPL metabolism.

Antioxidant, antiapoptotic and amino acid balance regulating activities of 1,7-dihydroxy-3,4,8-trimethoxyxanthone against dimethylnitrosamine-induced liver fibrosis.

Liver fibrosis represents the consequences of a sustained wound healing response to chronic liver injury which could be caused by viral, autoimmune, drugs, and so on. Unfortunately, there was no effective therapy available for liver fibrosis in clinic. In this study, we identified the anti-fibrotic effects of 1,7-dihydroxy-3,4,8-trimethoxyxanthone (ZYC-1) on the dimethylnitrosamine (DMN)-induced rat model. ZYC-1 was isolated from Swertia punicea Hemsl and was administrated to DMN-induced rat model. ZYC decreased the hyaluronic acid (HA), type IV collagen (CIV) and hydroxyproline (Hyp) levels and inhibited the expression of α smooth muscle actin (α-SMA) and transforming growth factor beta 1 (TGF-1β). The anti-fibrotic effect of ZYC-1 was also confirmed by Sirius Red staining. Finally, we identified 42 differentially expressed proteins by using proteomics analysis after ZYC-1 treatment, of which 17 were up-regulated and 25 were down-regulated. These Most of the 42 proteins are involved in the oxidative stress pathway, the mitochondrial-mediated apoptotic pathway and the amino acid metabolism pathway. Our study presented the first elucidated mechanisms of xanthone on liver fibrosis in vivo. This study pointed out that ZYC-1 may be used as a lead compound for hepatofibrosis treatment.

Effects of Dl-3-n-butylphthalide on Cerebral Ischemia Infarction in Rat Model by Mass Spectrometry Imaging

Dl-3-n-butylphthalide (NBP) is a drug that is used in the treatment of ischaemic stroke. However, to the best of our knowledge, there are no systematic studies investigating the effects of dl-3-n-butylphtalide on the brain metabolism of small molecules. In this study, we first investigated the effects of dl-3-n-butylphthalide on the spatial distribution of small molecules in the brains of rats with permanent middle cerebral artery occlusion (pMCAO) using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI–TOF–MS) imaging. After pMCAO modelling or a sham operation, rats were given four mg/kg of dl-3-n-butylphthalide through the caudal vein or saline once a day for nine days. The degree of neurological deficit in rats was evaluated using the modified neurological severity score (mNSS). MALDI–TOF–MS imaging was used to observe the content and distribution of small molecules related to metabolism during focal cerebral ischaemia. Multiple reaction monitoring (MRM) mode with liquid chromatography tandem mass spectrometry (LC–MS/MS) was used to verify the results obtained from MALDI–TOF–MS imaging. These small molecules were found to be involved in glucose metabolism, ATP metabolism, the glutamate–glutamine cycle, malate aspartate shuttle, oxidative stress, and inorganic ion homeostasis. Of the 13 metabolites identified by MALDI–TOF–MS imaging, seven compounds, ATP, ADP, AMP, GMP, N-acetylaspartic acid, ascorbic acid and glutathione, were further validated by LC–MS/MS. Taken together, these results indicate that dl-3-n-butylphthalide significantly improved ATP metabolism, level of antioxidants, and sodium-potassium ion balance in a rat model of pMCAO.