Xiao-Ping Pu

Antifibrotic effects of chronic baicalein administration in a CCl4 liver fibrosis model in rats.

Baicalein was a major bioactive flavonoid derived from Radix Scutellariae in Xiao-Chai-Hu-Tang which was commonly used to treat chronic hepatitis and liver fibrosis in China. The aim of this study was to assess whether chronic baicalein administration could prevent liver fibrosis induced by carbon tetrachloride (CCl(4)) in rats and investigate its possible protective mechanism. The antifibrotic effects of baicalein were assessed directly by hepatic histology and indirectly by measuring levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), hepatic hyaluronic acid, laminin and procollagen type III (PCIII) in serum, as well as hydroxyproline and matrix metalloproteinases (MMPs) in liver. In addition, we further investigated protein synthesis of platelet derived growth factor (PDGF) beta receptor which has been identified as attractive target for therapeutic intervention. CCl(4) treatment increased levels of AST, ALT, hyaluronic acid, laminin, and PCIII in serum, as well as hydroxyproline and MMPs in liver. Baicalein treatment (20, 40, or 80 mg/kg for 10 weeks) dose-dependently decreased levels of these markers. Baicalein also reduced inflammation, destruction of liver architecture, and collagen accumulation and significantly inhibited protein synthesis of PDGF-beta receptor. Together, our results suggest that chronic baicalein administration inhibits stellate cell activation and proliferation by the down-regulation of PDGF-beta receptor and prevents the development of CCl(4) induced liver fibrosis in rats.

Protocatechuic acid inhibits neurotoxicity induced by MPTP in vivo

Parkinsons disease (PD) is characterized by the progressive degeneration of dopaminergic neurons in substantia nigra (SN) with the presence of alpha-synuclein inclusions termed Lewy bodies. The neuroprotective effects of protocatechuic acid (PAc) both in vitro and in vivo have been reported. However, little is known about the effects of PAc on neurotoxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in vivo. In this study, we demonstrated that PAc inhibited the reduction of the latent periods in a rotarod test, and the contents of dopamine (DA) and its metabolites in striatum, and furthermore, it ameliorated the pathology in SN and the decreases in the expression of tyrosine hydroxylase (TH) in SN of C57BL/6J mice induced by MPTP. Taken together, our results indicate for the first time that PAc has neuroprotective effects on MPTP treated C57BL/6J mice and may be useful in clinical treatment of PD.

Design, synthesis and biological characterization of novel inhibitors of CD38.

Human CD38 is a novel multi-functional protein that acts not only as an antigen for B-lymphocyte activation, but also as an enzyme catalyzing the synthesis of a Ca(2+) messenger molecule, cyclic ADP-ribose, from NAD(+). It is well established that this novel Ca(2+) signaling enzyme is responsible for regulating a wide range of physiological functions. Based on the crystal structure of the CD38/NAD(+) complex, we synthesized a series of simplified N-substituted nicotinamide derivatives (Compound 1-14). A number of these compounds exhibited moderate inhibition of the NAD(+) utilizing activity of CD38, with Compound 4 showing the highest potency. The crystal structure of CD38/Compound 4 complex and computer simulation of Compound 7 docking to CD38 show a significant role of the nicotinamide moiety and the distal aromatic group of the compounds for substrate recognition by the active site of CD38. Biologically, we showed that both Compounds 4 and 7 effectively relaxed the agonist-induced contraction of muscle preparations from rats and guinea pigs. This study is a rational design of inhibitors for CD38 that exhibit important physiological effects, and can serve as a model for future drug development.

DJ-1 protein protects dopaminergic neurons against 6-OHDA/MG-132-induced neurotoxicity in rats

Parkinson disease (PD) is the second most common neurodegenerative disease, and it cannot be completely cured by current medications. In this study, DJ-1 protein was administrated into medial forebrain bundle of PD model rats those had been microinjected with 6-hydroxydopamine (6-OHDA) or MG-132. We found that DJ-1 protein could reduce apomorphine-induced rotations, inhibit reduction of dopamine contents and tyrosine hydroxylase levels in the striatum, and decrease dopaminergic neuron death in the substantia nigra. In 6-OHDA lesioned rats, uncoupling protein-4, uncoupling protein-5 and superoxide dismutase-2 (SOD2) mRNA and SOD2 protein were increased when DJ-1 protein was co-injected. Simultaneously, administration of DJ-1 protein reduced α-synuclein and hypoxia-inducible factor 1α mRNA and α-synuclein protein in MG-132 lesioned rats. Therefore, DJ-1 protein protected dopaminergic neurons in two PD model rats by increasing antioxidant capacity and inhibiting α-synuclein expression.

Neuroprotective xanthone glycosides from Swertia punicea.

Two new dimeric xanthone O-glycosides, puniceasides A (1) and B (2), a new trimeric O-glycoside, puniceaside C (3), and two new trimeric C-glycosides, puniceasides D (4) and E (5), together with 12 known xanthones were isolated from the entire plant of Swertia punicea. The structures of 1-5 were determined by HRESIMS and NMR spectroscopic methods. Compounds 2, 6, and 7 exhibited potent neuroprotective activity against H(2)O(2)-induced PC12 cell damage.

Effects of chronic morphine treatment on protein expression in rat dorsal root ganglia.

The initial aim of this study was to identify protein changes in the dorsal root ganglia (DRG) associated with long-term morphine treatment. We carried out a differential proteomics analysis on samples from the DRG of control and morphine-dependent rats (5-40 mg/kg, subcutaneously, twice daily for 28 days) after 4 days of morphine withdrawal. Proteins showing a statistically significant variation between the two groups were selected for identification by mass spectrometric analysis. Twelve proteins were unambiguously identified, with the majority being enzymes involved in energy metabolism and protein degradation, signaling and cytoskeletal proteins. Aldolase C and proteasome subunit alpha type 3 (PRC8 or alpha7) were further examined by Western blot analysis in the DRG, prefrontal cortex, nucleus accumbens, striatum, hippocampus, ventral tegmental area and locus coeruleus. In addition, expression of PRC8 in the nucleus accumbens tissue after spontaneous or naloxone-precipitated withdrawal was determined using immunohistochemical staining. Our results indicate that the expression levels of aldolase C and PRC8 proteins were altered in a time- and region-specific manner, and suggest that they could be implicated in the molecular changes underlying adaptations of neurons observed with chronic morphine treatment.

Down-regulation of DJ-1 protein in the ejaculated spermatozoa from Chinese asthenozoospermia patients

OBJECTIVEnTo determine whether the expression of DJ-1 protein, whose levels in spermatozoa have been reported to be highly correlated with male infertility caused by toxicants, is changed in spermatozoa of Chinese asthenozoospermia patients.nnnDESIGNnDJ-1 measurement by Western blotting, quantitive ELISA, and isoelectric-focusing electrophoresis (IFE) combined with immunoblotting.nnnSETTINGnAcademic medical center and research laboratories.nnnPATIENT(S)nAsthenozoospermia patients (n = 113), including mild asthenozoospermia patients (n = 70) and moderate asthenozoospermia patients (n = 43), and age-matched control subjects (n = 58).nnnINTERVENTION(S)nNone.nnnMAIN OUTCOME MEASURE(S)nDJ-1 in spermatozoa was determined by Western blotting and ELISA, the isoelectric point (pI) of DJ-1 by IFE combined with immunoblotting, and sperm superoxide dismutase (SOD) activity by an assay kit.nnnRESULT(S)nThe sperm DJ-1 concentration in moderate asthenozoospermia patients was lower than those in mild asthenozoospermia patients and control subjects. DJ-1 with a more acidic pI was increased in asthenozoospermia patients. Sperm SOD activity was decreased in asthenozoospermia patients.nnnCONCLUSION(S)nDJ-1 levels are reduced in moderate asthenozoospermia patients. DJ-1 concentration is positively correlated with sperm motility and sperm SOD activity indicated by partial correlation analysis.

Proteome analysis of the sera from Chinese Parkinson's disease patients

Clinical proteomics is a powerful tool that can be used to identify proteins that are differentially expressed in disease states, leading to greater understanding of the molecular and cellular events that contribute to disease. The aim of this study was to identify protein changes in the sera from Chinese Parkinsons disease (PD) patients, with the goal of finding biomarkers for PD diagnosis, and to elucidate the events occurring at the onset of PD. Using differential display to identify proteins with altered expression in PD patients, we obtained 15 protein spots corresponding to 13 different gene products that were likely to be involved in PD. Two-dimensional gel electrophoresis and mass spectrometry were used to identify differentially expressed proteins, 7 of which have never previously been associated with PD patients. They are likely to be involved in antioxidation, lipid metabolism, intracellular transport, cell proliferation and immunoregulation. The altered levels of these proteins may be related to the pathophysiological mechanisms of PD. As a result, some of these proteins could be considered as candidate biomarkers.

Chronic morphine administration induces over-expression of aldolase C with reduction of CREB phosphorylation in the mouse hippocampus

In recent studies, alterations in the activity and expression of metabolic enzymes, such as those involved in glycolysis, have been detected in morphine-dependent patients and animals. Increasing evidence demonstrates that the hippocampus is an important brain region associated with morphine dependence, but the molecular events occurring in the hippocampus following chronic exposure to morphine are poorly understood. Aldolase C is the brain-specific isoform of fructose-1, 6-bisphosphate aldolase which is a glycolytic enzyme catalyzing reactions in the glycolytic, gluconeogenic, and fructose metabolic pathways. Using Western blot and immunofluorescence assays, we found the expression of aldolase C was markedly increased in the mouse hippocampus following chronic morphine treatment. Naloxone pretreatment before morphine administration suppressed withdrawal jumping, weight loss, and overexpression of aldolase C. CREB is a transcription factor regulated through phosphorylation on Ser133, which is known to play a key role in the mechanism of morphine dependence. When detecting the expression of phosphorylated CREB (p-CREB) in the mouse hippocampus using Western blot and immunohistochemistry, we found CREB phosphorylation was clearly decreased following chronic morphine treatment. Interestingly, laser-confocal microscopy showed that overexpression of aldolase C in mouse hippocampal neurons was concomitant with the decreased immunoreactivity of p-CREB. The results suggest potential links between the morphine-induced alteration of aldolase C and the regulation of CREB phosphorylation, a possible mechanism of morphine dependence.

Proteome analysis of substantia nigra and striatal tissue in the mouse MPTP model of Parkinson's disease

The dopaminergic neurotoxin 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) replicates many of the pathological hallmarks of Parkinsons disease (PD) in mice via selective destruction of dopamine neurons of the substantia nigra and striatum. Although MPTP has been widely used to study downstream effects following the degeneration of dopaminergic neurons, the underlying mechanisms of MPTP action remain poorly understood. To determine the underlying mechanisms of MPTP action at the protein level, a 2‐DE‐based proteomics approach was used to evaluate the changes in protein expression in substantia nigra and striatal tissue in C57BL/6 mice after MPTP administration. We identified nine proteins that were markedly altered and are likely to be involved in mitochondrial function, heat shock protein activity, and which contribute enzyme activities for energy metabolism and protein degradation.