Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.5.1.18 (glutathione S-transferase)
 22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human exposure to dithiocarbamates results from their uses as pesticides, in manufacturing, and as pharmaceutical agents. Neurotoxicity is an established hazard of dithiocarbamate exposure and has been observed in both humans and experimental animals. Previous studies have shown that the neurotoxicity of certain dithiocarbamates, including N,N-diethyldithiocarbamate (DEDC), disulfiram, and pyrrolidine dithiocarbamate, can manifest as a primary myelinopathy of peripheral nerves. Because increased levels of copper in peripheral nerves and elevated levels of lipid peroxidation products accompany DEDC-induced lesions, it has been suggested that the disruption of copper homeostasis and increased oxidative stress may contribute to myelin injury. To further assess the biological impact of DEDC-mediated lipid peroxidation in nerves, the changes in protein expression levels resulting from DEDC exposure were determined. In addition, protein carbonyl content in peripheral nerves was also determined as an initial assessment of protein oxidative damage in DEDC neuropathy. Rats were exposed to DEDC by intra-abdominal osmotic pumps for eight weeks and proteins extracted from the sciatic nerves of DEDC-exposed animals and from non-exposed controls. The comparison of protein expression levels using two-dimensional difference gel electrophoresis demonstrated significant changes in 56 spots of which 46 were identified by MALDI-TOF/MS. Among the proteins showing increased expression were three isoforms of glutathione transferase, important for the detoxification of reactive alpha,beta-unsaturated aldehydes generated from lipid peroxidation. The increased expression of one isoform, glutathione transferase pi, was localized to the cytoplasm of Schwann cells using immunohistochemistry. An immunoassay for nerve protein carbonyls demonstrated a significant increase of approximately 2-fold for the proteins isolated from DEDC-exposed rats. These data support the ability of DEDC to promote protein oxidative damage in peripheral nerves and to produce sufficient lipid peroxidation in either myelin or another component of the Schwann cell to elicit a protective cellular response to oxidative stress.
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PMID:Peripheral nerve protein expression and carbonyl content in N,N-diethlydithiocarbamate myelinopathy. 1732 79

Dithiocarbamates are a commercially important class of compounds that can produce peripheral neuropathy in humans and experimental animals. Previous studies have supported a requirement for copper accumulation and enhanced lipid peroxidation in dithiocarbamate-mediated myelinopathy. The study presented here extends previous investigations in two areas. Firstly, although total copper levels have been shown to increase within the nerve it has not been determined whether copper is increased within the myelin compartment, the primary site of lesion development. Therefore, the distribution of copper in sciatic nerve was characterized using synchrotron X-ray fluorescence microscopy to determine whether the neurotoxic dithiocarbamate, N,N-diethyldithiocarbamate, increases copper levels in myelin. Secondly, because lipid peroxidation is an ongoing process in normal nerve and the levels of lipid peroxidation products produced by dithiocarbamate exposure demonstrated an unusual cumulative dose response in previous studies the biological impact of dithiocarbamate-mediated lipid peroxidation was evaluated. Experiments were performed to determine whether dithiocarbamate-mediated lipid peroxidation products elicit an antioxidant response through measuring the protein expression levels of three enzymes, superoxide dismutase 1, heme oxygenase 1, and glutathione transferase alpha, that are linked to the antioxidant response element promoter. To establish the potential of oxidative injury to contribute to myelin injury the temporal relationship of the antioxidant response to myelin injury was determined. Myelin structure in peripheral nerve was assessed using multi-exponential transverse relaxation measurements (MET(2)) as a function of exposure duration, and the temporal relationship of protein expression changes relative to the onset of changes in myelin integrity were determined. Initial assessments were also performed to explore the potential contribution of dithiocarbamate-mediated inhibition of proteasome function and inhibition of cuproenzyme activity to neurotoxicity, and also to assess the potential of dithiocarbamates to promote oxidative stress and injury within the central nervous system. These evaluations were performed using an established model for dithiocarbamate-mediated demyelination in the rat utilizing sciatic nerve, spinal cord and brain samples obtained from rats exposed to N,N-diethyldithiocarbamate (DEDC) by intra-abdominal pumps for periods of 2, 4, and 8 weeks and from non exposed controls. The data supported the ability of DEDC to increase copper within myelin and to enhance oxidative stress prior to structural changes detectable by MET(2). Evidence was also obtained that the excess copper produced by DEDC in the central nervous system is redox active and promotes oxidative injury.
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PMID:N,N-diethyldithiocarbamate promotes oxidative stress prior to myelin structural changes and increases myelin copper content. 1946 51