Guangyan Yan

Zinc oxide nanoparticles cause nephrotoxicity and kidney metabolism alterations in rats

Although zinc oxide nanoparticles (ZnO NPs) have been widely used, their potential hazards on mammalian and human remain largely unknown. In this study, the biochemical compositions of urine and kidney from the rats treated with ZnO NPs (100, 300 and 1000 mg/kg, respectively) were investigated using 1H nuclear magnetic resonance (NMR) technique with the pattern recognition of partial least squares-discriminant analysis. Hematology, clinical biochemistry and kidney histopathological examinations were also performed. Metabolic profiles from rats treated with ZnO NPS exhibited increases in the levels of taurine, lactate, acetate, creatine, phosphocholine, trimethylamine-N-oxide, α-glucose, and 3-D-hydroxybutyrate, as well as decreases in lipid, succinate, citrate, α-ketoglutarate, hippurate and 4-hydroxyphenylacetic acid in urine after ZnO NPs treatment for 14 days. A similar alteration pattern was also identified in kidney. Urine choline and phosphocholine increased significantly shortly after ZnO NPs treatment, moreover, some amino acids and glucose also increased during the experimental period. However, succinate, citrate and α-ketoglutarate in urine exhibited a different alteration trend, which showed increases on the first day after ZnO NPs treatment, but decreases gradually until the termination of the study. A similar alteration pattern of urinary 1H NMR spectra was also detected in kidney. Moreover, ZnO NPs (1000 mg/kg) resulted in significant increases in serum creatine and blood urea nitrogen, decreases in hemoglobin, haematocrit and mean corpuscular hemoglobin concentration, and overt tubular epithelial cell necrosis. These findings show that ZnO NPs can disturb the energy metabolism and cause mitochondria and cell membrane impairment in rat kidney, which may contribute to ZnO NPs-induced nephrotoxicity.

Transcriptome analysis of long non-coding RNAs of the nucleus accumbens in cocaine-conditioned mice

Cocaine dependence involves in the brains reward circuit as well as nucleus accumbens (NAc), a key region of the mesolimbic dopamine pathway. Many studies have documented altered expression of genes and identified transcription factor networks and epigenetic processes that are fundamental to cocaine addiction. However, all these investigations have focused on mRNA of encoding genes, which may not always reflect the involvement of long non‐coding RNAs (lncRNAs), which has been implied in a broad range of biological processes and complex diseases including brain development and neuropathological process. To explore the potential involvement of lncRNAs in drug addiction, which is viewed as a form of aberrant neuroplasticity, we used a custom‐designed microarray to examine the expression profiles of mRNAs and lncRNAs in brain NAc of cocaine‐conditioned mice and identified 764 mRNAs, and 603 lncRNAs were differentially expressed. Candidate lncRNAs were identified for further genomic context characterization as sense‐overlap, antisense‐overlap, intergenic, bidirection, and ultra‐conserved region encoding lncRNAs. We found that 410 candidate lncRNAs which have been reported to act in cis or trans to their targeted loci, providing 48 pair mRNA‐lncRNAs. These results suggest that the modification of mRNAs expression by cocaine may be associated with the actions of lncRNAs. Taken together, our results show that cocaine can cause the genome‐wide alterations of lncRNAs expressed in NAc, and some of these modified RNA transcripts may to play a role in cocaine‐induced neural plasticity and addiction.

Proteomic analysis of the nucleus accumbens in rhesus monkeys of morphine dependence and withdrawal intervention

It has been known that the reinforcing effects and long-term consequences of morphine are closely associated with nucleus accumbens (NAc) in the brain, a key region of the mesolimbic dopamine pathway. However, the proteins involved in neuroadaptive processes and withdrawal symptom in primates of morphine dependence have not been well explored. In the present study, we performed proteomes in the NAc of rhesus monkeys of morphine dependence and withdrawal intervention with clonidine or methadone. Two-dimensional electrophoresis was used to compare changes in cytosolic protein abundance in the NAc. We found a total of 46 proteins differentially expressed, which were further identified by mass spectrometry analysis. The identified proteins can be classified into 6 classes: metabolism and mitochondrial function, synaptic transmission, cytoskeletal proteins, oxidative stress, signal transduction and protein synthesis and degradation. Importantly, we discovered 14 proteins were significantly but similarly altered after withdrawal therapy with clonidine or methadone, revealing potential pharmacological strategies or targets for the treatment of morphine addiction. Our study provides a comprehensive understanding of the neuropathophysiology associated with morphine addiction and withdrawal therapy in primate, which is helpful for the development of opiate withdrawal pharmacotherapies.

Metabolomics: A Revolution for Novel Cancer Marker Identification

The repertoire of small-molecular-weight substances present in cells, tissue and body fluids are known as the metabolites. The global analysis of metabolites, such as by high-resolution ¹H nuclear magnetic resonance spectroscopy and mass spectrometry, is integral to the rapidly expanding field of metabolomics, which is making progress in various diseases. In the area of cancer and metabolic phenotype, the integrated analysis of metabolites may provide a powerful platform for detecting changes related to cancer diagnosis and discovering novel biomarkers. In this review, metabolomics including the technologies in metabolomics research and extracting information from metabolomics datasets are described. Then we discuss the challenges and opportunities in metabolomics for finding metabolic processes in cancer and discovering novel cancer biomarkers. Finally, we assess the clinical applicability of metabolomics.

NMR-based metabonomic in hippocampus, nucleus accumbens and prefrontal cortex of methamphetamine-sensitized rats

(1)H NMR spectroscopy was applied to investigate the changes of cerebral metabolites in brain hippocampus, nucleus accumbens (NAC) and prefrontal cortex (PFC) of the rats subjected to subcutaneous twice-daily injections of 2.5mg/kg methamphetamine (MAP) for 7 days. The results indicated that MAP exposure induced significant behavioral sensitization and altered cerebral metabolites in rats. The neurotransmitters glutamate, glutamine and GABA significantly decreased in hippocampus, NAC and PFC. Specifically, increased succinic acid semialdehyde, a metabolism product of GABA, was observed in hippocampus. Additionally, decreased serotonin was observed in both NAC and PFC, whereas decreased dopamine was only observed in NAC after repeated MAP treatment. Glutathione obviously decreased in above brain regions, whereas acetylcysteine declined in hippocampus and NAC, and taurine declined in NAC and PFC. Homocysteic acid was elevated in hippocampus and NAC by repeated MAP administration. Membrane ingredients like phosphocholine elevated in response to MAP administration in NAC and PFC. N-Acetyl-aspartate, a marker of neuronal viability, decreased in the three regions; however, myo-inositol, a glial cell marker, increased in hippocampus and PFC. Tricarboxylic acid cycle intermediate products, such as α-ketoglutarate, succinate, citrate and the methionine significantly decreased in above three brain regions after MAP administration; however, ADP decreased in hippocampus. These results indicate that repeated MAP treatment causes neurotransmitters disturbance, imbalance between oxidative stress and antioxidants, and gliosis in hippocampus, NAC and PFC. Profound metabolic changes detected across brain regions provide the first evidence of metabonomic changes in MAP-induced sensitized rats.

1H NMR-based metabonomic analysis of brain in rats of morphine dependence and withdrawal intervention

Metabolic consequences of morphine dependence and withdrawal intervention have not been well explored. In the present study, the metabolic changes in brain hippocampus, nucleus accumbens (NAc), prefrontal cortex (PFC) and striatum of rats with morphine dependence and withdrawal intervention were explored by using ¹H nuclear magnetic resonance coupled with principal component analysis, partial least squares and orthogonal signal correction analysis. We found that the concentrations of neurotransmitters including glutamate, glutamine and gamma-aminobutyric acid changed differentially in hippocampus, NAc, PFC and striatum after repeated morphine treatment. Significant changes were also found in a number of cerebral metabolites including N-acetyl aspartate (NAA), lactic acid, creatine, myo-inositol and taurine. These findings indicate the profound disturbances of energy metabolism, amino acid metabolism and neurotransmitters caused by chronic morphine treatment. Interestingly, morphine-induced changes in lactic acid, creatine and NAA were clearly reversed by intervention of methadone or clonidine. Our study provides a comprehensive understanding of the metabolic alteration associated with morphine addiction and withdrawal therapy, which may help to develop new pharmacotherapies.

Taurine protects methamphetamine-induced developmental angiogenesis defect through antioxidant mechanism.

Investigations have characterized addictive drug-induced developmental cardiovascular malformation in human, non-human primate and rodent. However, the underlying mechanism of malformation caused by drugs during pregnancy is still largely unknown, and preventive and therapeutic measures have been lacking. Using 1H NMR spectroscopy, we profiled the metabolites from human embryo endothelial cells exposed to methamphetamine (METH) and quantified a total of 226 peaks. We identified 11 metabolites modified robustly and found that taurine markedly increased. We then validated the hypothesis that this dramatic increase in taurine could attribute to its effect in inhibiting METH-induced developmental angiogenesis defect. Taurine supplement showed a more significant potential than other metabolites in protecting against METH-induced injury in endothelial cells. Taurine strongly attenuated METH-induced inhibition of proliferation and migration in endothelial cells. Furthermore, death rate and vessel abnormality of zebrafish embryos treated with METH were greatly reversed by taurine. In addition, taurine supplement caused a rapid decrease in reactive oxygen species generation and strongly attenuated the excitable arise of antioxidase activities in the beginning of METH exposure prophase. Dysregulations of NF-κB, p-ERK as well as Bax, which reflect apoptosis, cell cycle arrest and oxidative stress in vascular endothelium, were blocked by taurine. Our results provide the first evidence that taurine prevents METH-caused developmental angiogenesis defect through antioxidant mechanism. Taurine could serve as a potential therapeutic or preventive intervention of developmental vascular malformation for the pregnant women with drug use.

1H NMR-based metabonomics in brain nucleus accumbens and striatum following repeated cocaine treatment in rats

Studies have shown a few cerebral metabolites modified by cocaine in brain regions; however, endogenous metabolic profiling has been lacking. Ex vivo (1)H NMR (hydrogen-1 nuclear magnetic resonance) spectroscopy-based metabonomic approach coupled with partial least squares was applied to investigate the changes of cerebral metabolites in nucleus accumbens (NAc) and striatum of rats subjected to cocaine treatment. Our results showed that both single and repeated cocaine treatment can induce significant changes in a couple of cerebral metabolites. The increase of neurotransmitters glutamate and gamma-amino butyric acid (GABA) were observed in NAc and striatum from the rats repeatedly treated with cocaine. Creatine and taurine increased in NAc whereas taurine increased and creatine decreased in striatum after repeated cocaine treatment. Elevation of N-acetylaspartate in NAc and striatum and decrease of lactate in striatum were observed, which may reflect the mitochondria dysregulation caused by cocaine; moreover, alterations of choline, phosphocholine and glycerol in NAc and striatum could be related to membrane disruption. Moreover, groups of rats with and without conditioned place preference (CPP) apparatus are presenting difference in metabolites. Collectively, our results provide the first evidence of metabonomic profiling of NAc and striatum in response to cocaine, exhibiting a regionally-specific alteration patterns. We find that repeated cocaine administration leads to significant metabolite alterations, which are involved in neurotransmitter disturbance, oxidative stress, mitochondria dysregulation and membrane disruption in brain.

1H-nuclear magnetic resonance-based metabonomic analysis of brain in rhesus monkeys with morphine treatment and withdrawal intervention

Comprehensive cerebral metabolites involved in morphine dependence have not been well explored. To gain a better understanding of morphine dependence and withdrawal therapy in a model highly related to humans, metabolic changes in brain hippocampus and prefrontal cortex (PFC) of rhesus monkeys were measured by 1H‐nuclear magnetic resonance spectroscopy, coupled with partial least squares and orthogonal signal correction analysis. The results showed that concentrations of myoinositol (M‐Ins) and taurine were significantly reduced, whereas lactic acid was increased in hippocampus and PFC of morphine‐dependent monkeys. Phosphocholine and creatine increased in PFC but decreased in hippocampus after chronic treatment of morphine. Moreover, N‐acetyl aspartate (NAA), γ‐aminobutyric acid, glutamate, glutathione, methionine, and homocysteic acid also changed in these brain regions. These results suggest that chronic morphine exposure causes profound disturbances of neurotransmitters, membrane, and energy metabolism in the brain. Notably, morphine‐induced dysregulations in NAA, creatine, lactic acid, taurine, M‐Ins, and phosphocholine were clearly reversed after intervention with methadone or clonidine. Our study highlights the potential of metabolic profiling to enhance our understanding of metabolite alteration and neurobiological actions associated with morphine addiction and withdrawal therapy in primates.

Investigation of toxicological effects of Shuanghuanglian injection in Beagle dogs by metabonomic and traditional approaches.

In this study, clinical biochemistry, hematology, histopathology and 1H nuclear magnetic resonance spectroscopy-based metabonomic approaches were applied to investigate the toxicological effects of Shuanghuanglian (SHL) injection after intravenous administration (dosed at 4, 12 and 36 mL stock/kg) in Beagle dogs for 30 d. Decreases in red blood cells, hemoglobin, mean cell volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were observed in the high-dose group. Elevated reticulocytes, total bilirubin and direct bilirubin were also observed in this group. Moreover, significant hemosiderosis and Prussian blue positivity were detected in the liver, spleen and kidney from high-dose group animals, and transmission electron microscopy examination revealed an appreciable number of acanthrocytes in the liver. These results collectively indicate that SHL injection has the potential to cause hemolytic anemia. Metabonomic analysis showed increases in serum lactate, choline and phosphocholine but a decrease in taurine in treated groups and these findings may underlie the toxicological mechanism of SHL injection. In summary, SHL injection shows hemolytic effects in Beagle dogs; moreover, serum choline and phosphocholine as well as lactate and taurine may be the biomarkers for hemolytic anemia induced by SHL injection.