The effect of phencyclidine-mediated blockade of NMDA receptors in the early postnatal period on glutathione and sulfur amino acid levels in the rat brain as a potential causative factor of schizophrenia-like behavior in adulthood.

BACKGROUND: Phencyclidine, an NMDA receptor antagonist, is frequently used to model behavioral and neurochemical changes correlated with schizophrenia in laboratory animals. The present study aimed to examine the effects of repeated administration of phencyclidine during early postnatal development on the contents of glutathione and sulfur-containing amino acids, as well as the activity of antioxidant enzymes in the brain of 12-day-old rats, and schizophrenia-like symptoms in adulthood. METHODS: Male Sprague-Dawley pups were administered phencyclidine (10 mg/kg) or saline subcutaneously on the postnatal days p2, p6, p9 and p12. In 12-day-old pups, 4 h after the last dose of phencyclidine, the levels of glutathione, cysteine, methionine, and homocysteine, and the enzymatic activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) were measured in the frontal cortex, hippocampus, and striatum. In 70-72-day-old rats, schizophrenia-like symptoms were assessed using behavioral tests. RESULTS: Biochemical data showed that perinatal phencyclidine treatment significantly reduced glutathione and cysteine levels in all brain structures studied, methionine was diminished in the striatum, and homocysteine in both the frontal cortex and striatum. GR activity was increased in the frontal cortex while SODactivity was decreased in the hippocampus. Behaviorally, perinatal phencyclidine induced long-term deficits in social and cognitive function and a decrease in locomotor activity assessed as the time of walking. Finally, perinatal treatment with phencyclidine resulted in a significant reduction in body weight gain over time. CONCLUSION: Our research provides further evidence for the usefulness of the phencyclidine-induced neurodevelopmental model of schizophrenia for studying the pathogenesis of schizophrenia.

Treatment with aripiprazole and N-acetylcysteine affects anaerobic cysteine metabolism in the hippocampus and reverses schizophrenia-like behavior in the neurodevelopmental rat model of schizophrenia.

Preclinical and clinical studies have shown that the antipsychotic drug aripiprazole and the antioxidant N-acetylcysteine have unique biological properties. The aim of the study was to investigate, in a rat model of schizophrenia, the effects of chronic administration of these drugs on schizophrenia-like behaviors and anaerobic cysteine metabolism in the hippocampus (HIP). The schizophrenia-type changes were induced in Sprague-Dawley rats by repeated administration of the glutathione synthesis inhibitor l-butionine-(S,R)-sulfoximine in combination with the dopamine reuptake inhibitor GBR 12909 in the early postnatal period. Adult model rats were chronically treated with aripiprazole (0.3 mg·kg-1 , i.p.) or N-acetylcysteine (30 mg·kg-1 , orally), and their effects on schizophrenia-like behaviors were assessed using the social interaction test and novel object recognition test. In the HIP, the level of anaerobic cysteine metabolites, H2 S, and bound sulfane sulfur were determined by a fluorescence method, while the expression of H2 S-synthetizing enzymes: cystathionine ß-synthase (CBS) and mercaptopyruvate sulfurtransferase (MST) by western blot. Long-term treatment with aripiprazole or N-acetylcysteine reversed social and cognitive deficits and reduced the exploratory behaviors. In the HIP of 16-day-old model pups, H2 S levels and MST protein expression were significantly decreased. In adult model rats, H2 S levels remained unchanged, bound sulfane sulfur significantly increased, and the expression of CBS and MST slightly decreased. The studied drugs significantly reduced the level of bound sulfane sulfur and the expression of tested enzymes. The reduction in bound sulfane sulfur level coincided with the attenuation of exploratory behavior, suggesting that modulation of anaerobic cysteine metabolism in the HIP may have therapeutic potential in schizophrenia.

Reactive Sulfur Species in Human Diseases.

Significance: Reactive sulfur species (RSS) have been recently recognized as redox molecules no less important than reactive oxygen species or reactive nitrogen species. They possess regulatory and protective properties and are involved in various metabolic processes, thereby contributing to the maintenance of human health. It has been documented that many disorders, including neurological, cardiovascular, and respiratory diseases, diabetes mellitus (DM), and cancer, are related to the disruption of RSS homeostasis. Recent Advances: There is still a growing interest in the role of RSS in human diseases. Since a decrease in hydrogen sulfide or other RSS has been reported in many disorders, safe and efficient RSS donors have been developed and tested under in vitro conditions or on animal models. Critical Issues: Cardiovascular diseases and DM are currently the most common chronic diseases worldwide due to stressful and unhealthy lifestyles. In addition, because of high prevalence and aging of the population, neurological disorders including Parkinson's disease and Alzheimer's disease as well as respiratory diseases are a formidable challenge for health care systems. From this point of view, the knowledge of the role of RSS in these disorders and RSS modulation options are important and could be useful in therapeutic strategies. Future Directions: Improvement and standardization of analytical methods used for RSS estimation are crucial for the use of RSS as diagnostic biomarkers. Finding good, safe RSS donors applicable for therapeutic purposes could be useful as primary or adjunctive therapy in many common diseases. Antioxid. Redox Signal. 39, 1000-1023.

Yohimbine Alleviates Oxidative Stress and Suppresses Aerobic Cysteine Metabolism Elevated in the Rat Liver of High-Fat Diet-Fed Rats.

Yohimbine is a small indole alkaloid derived from the bark of the yohimbe tree with documented biological activity, including anti-inflammatory, erectile dysfunction relieving, and fat-burning properties. Hydrogen sulfide (H2S) and sulfane sulfur-containing compounds are regarded as important molecules in redox regulation and are involved in many physiological processes. Recently, their role in the pathophysiology of obesity and obesity-induced liver injury was also reported. The aim of the present study was to verify whether the mechanism of biological activity of yohimbine is related to reactive sulfur species formed during cysteine catabolism. We tested the effect of yohimbine at doses of 2 and 5 mg/kg/day administered for 30 days on aerobic and anaerobic catabolism of cysteine and oxidative processes in the liver of high-fat diet (HFD)-induced obese rats. Our study revealed that HFD resulted in a decrease in cysteine and sulfane sulfur levels in the liver, while sulfates were elevated. In the liver of obese rats, rhodanese expression was diminished while lipid peroxidation increased. Yohimbine did not influence sulfane sulfur and thiol levels in the liver of obese rats, however, this alkaloid at a dose of 5 mg decreased sulfates to the control level and induced expression of rhodanese. Moreover, it diminished hepatic lipid peroxidation. It can be concluded that HFD attenuates anaerobic and enhances aerobic cysteine catabolism and induces lipid peroxidation in the rat liver. Yohimbine at a dose of 5 mg/kg can alleviate oxidative stress and reduce elevated concentrations of sulfate probably by the induction of TST expression.

Chemistry and Biochemistry Aspects of the 4-Hydroxy-2,3-trans-nonenal.

4-hydroxy-2,3-trans-nonenal (C9H16O2), also known as 4-hydroxy-2E-nonenal (C9H16O2; HNE) is an α,ß-unsaturated hydroxyalkenal. HNE is a major aldehyde, formed in the peroxidation process of ω-6 polyunsaturated fatty acids (ω-6 PUFAs), such as linoleic and arachidonic acid. HNE is not only harmful but also beneficial. In the 1980s, the HNE was regarded as a "toxic product of lipid peroxidation" and the "second toxic messenger of free radicals". However, already at the beginning of the 21st century, HNE was perceived as a reliable marker of oxidative stress, growth modulating factor and signaling molecule. Many literature data also indicate that an elevated level of HNE in blood plasma and cells of the animal and human body is observed in the course of many diseases, including cancer. On the other hand, it is currently proven that cancer cells divert to apoptosis if they are exposed to supraphysiological levels of HNE in the cancer microenvironment. In this review, we briefly summarize the current knowledge about the biological properties of HNE.

Evaluation of Cysteine Metabolism in the Rat Liver and Kidney Following Intravenous Cocaine Administration and Abstinence.

Many toxic effects of cocaine are attributed to reactive oxygen species (ROS) generated during its metabolism. Recently, it has been suggested that the biological action of ROS is often confused with endogenously generated reactive sulfur species (RSS). The aim of this study was to evaluate the impact of cocaine on thiols and RSS in the rat liver and kidney in the drug self-administration (SA) paradigm and the cocaine yoked delivery model (YC) followed by drug abstinence with extinction training. The level of thiols as well as RSS formed during anaerobic metabolism of cysteine and sulfate were assayed. In addition, the activity of enzymes involved in RSS formation and glutathione metabolism were determined. In the liver, following direct cocaine administration (SA and YC), the RSS levels decreased, while in the kidneys, cocaine increased the RSS contents in both groups. These changes were maintained in these tissues during drug abstinence. The level of sulfates was changed by cocaine only in the liver. In the kidney, cocaine shifted cysteine metabolism towards an anaerobic pathway. Our study demonstrates for the first time the changes in cysteine metabolism and thiol levels in the liver and kidney of rats after cocaine self-administration and abstinence.

Alterations in the Antioxidant Enzyme Activities in the Neurodevelopmental Rat Model of Schizophrenia Induced by Glutathione Deficiency during Early Postnatal Life.

The aim of the present study was to assess the effects of l-buthionine-(S,R)-sulfoximine (BSO), a glutathione (GSH) synthesis inhibitor, and GBR 12909, a dopamine reuptake inhibitor, administered alone or in combination to Sprague-Dawley rats during early postnatal development (p5-p16), on the levels of reactive oxygen species (ROS), lipid peroxidation (LP) and the activities of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione disulfide reductase (GR) in peripheral tissues (liver, kidney) and selected brain structures (prefrontal cortex, PFC; hippocampus, HIP; and striatum, STR) of 16-day-old rats. The studied parameters were analyzed with reference to the content of GSH and sulfur amino acids, methionine (Met) and cysteine (Cys) described in our previous study. This analysis showed that treatment with a BSO + GBR 12909 combination caused significant decreases in the lipid peroxidation levels in the PFC and HIP, in spite of there being no changes in ROS. The reduction of lipid peroxidation indicates a weakening of the oxidative power of the cells, and a shift in balance in favor of reducing processes. Such changes in cellular redox signaling in the PFC and HIP during early postnatal development may result in functional changes in adulthood.

Sulfane sulfur - new findings on an old topic.

Sulfane sulfur is a divalent sulfur atom bonded to another sulfur which is very reactive and labile. Compounds containing this reactive sulfur include persulfides, polysulfides, thiosulfate, thiosulfinates, polythionates, and elemental sulfur. Sulfane sulfur appears in a number of biologically important compounds, including thiocysteine, thiocystine and thiotaurine, products of the cysteine metabolism, as well as glutathione persulfide. Sulfane sulfur compounds can modify cysteine residues in proteins via an S-sulfhydration reaction to produce protein persulfides. It has been also postulated that cysteine persulfides can be incorporated into proteins during translation. Recently, the sulfane sulfur compounds, especially the persulfides and polysulfides, have attracted increasing interest due to their regulatory and antioxidant properties. Compounds containing sulfane sulfur are also regarded as a form of H2S storage, which can easily release this gasotransmitter in response to biological signals. Both reactive sulfur species (H2S and sulfane sulfur) always coexist in biological systems. This review is focused on new findings in the field of sulfane sulfur's biological role, and disruption of its level in some patho/physiological conditions. A few sulfane sulfur donors with potential applications are presented. In recent years, in parallel to increasing interest in biological importance of sulfane sulfur, new analytical methods have been developed for sensitive and reliable determination of its level in the cells and tissues.

Glutathione Deficiency and Alterations in the Sulfur Amino Acid Homeostasis during Early Postnatal Development as Potential Triggering Factors for Schizophrenia-Like Behavior in Adult Rats.

Impaired glutathione (GSH) synthesis and dopaminergic transmission are important factors in the pathophysiology of schizophrenia. Our research aimed to assess the effects of l-buthionine-(S,R)-sulfoximine (BSO), a GSH synthesis inhibitor, and GBR 12909, a dopamine reuptake inhibitor, administered alone or in combination, to Sprague-Dawley rats during early postnatal development (p5-p16), on the levels of GSH, sulfur amino acids, global DNA methylation, and schizophrenia-like behavior. GSH, methionine (Met), homocysteine (Hcy), and cysteine (Cys) contents were determined in the liver, kidney, and in the prefrontal cortex (PFC) and hippocampus (HIP) of 16-day-old rats. DNA methylation in the PFC and HIP and schizophrenia-like behavior were assessed in adulthood (p90-p93). BSO caused the tissue-dependent decreases in GSH content and alterations in Met, Hcy, and Cys levels in the peripheral tissues and in the PFC and HIP. The changes in these parameters were accompanied by alterations in the global DNA methylation in the studied brain structures. Parallel to changes in the global DNA methylation, deficits in the social behaviors and cognitive functions were observed in adulthood. Only BSO + GBR 12909-treated rats exhibited behavioral alterations resembling positive symptoms in schizophrenia patients. Our results suggest the usefulness of this neurodevelopmental model for research on the pathomechanism of schizophrenia.

The effect of NaCl on the level of reduced sulfur compounds in rat liver. Implications for blood pressure increase.

BACKGROUND: It is commonly known that excessive salt intake is a risk factor of hypertension. Currently, there is an increasing interest in reduced reactive sulfur species (RSS), mainly H2S and sulfane sulfur (SS) as new gasotransmitters showing vasorelaxant properties. The aim of the present study was to determine the effect of repeated administration of low sodium chloride dose included in physiological saline on blood pressure, on the level of RSS and activity of enzymes involved in their biosynthesis in the rat. METHODS: Two separate experiments were carried out on male Wistar rats: one with intravenous injections of saline and the second one with intraperitoneal saline injections. Blood pressure was measured during the experiment. The level of RSS and other biochemical assays were conducted in the rat liver, because of an intense cysteine metabolism to RSS in this organ. RESULTS: Intravenous administration of saline induced a significant increase in systolic blood pressure while intraperitoneal injections showed only a tendency towards increasing blood pressure. The RSS (H2S and SS) level as well as the activity of the main enzyme responsible for their production in the liver of animals after iv saline injections were decreased. Animals injected with physiological saline by ip route did not reveal any statistically significant differences in SS, H2S, and activities of sulfurtransferases, although a tendency to decrease in the RSS was observed. CONCLUSIONS: The repeated iv saline injection induced a slight hypertension accompanied by disturbances in anaerobic cysteine metabolism in the rat liver.

The Role of Hemoproteins: Hemoglobin, Myoglobin and Neuroglobin in Endogenous Thiosulfate Production Processes.

Thiosulfate formation and biodegradation processes link aerobic and anaerobic metabolism of cysteine. In these reactions, sulfite formed from thiosulfate is oxidized to sulfate while hydrogen sulfide is transformed into thiosulfate. These processes occurring mostly in mitochondria are described as a canonical hydrogen sulfide oxidation pathway. In this review, we discuss the current state of knowledge on the interactions between hydrogen sulfide and hemoglobin, myoglobin and neuroglobin and postulate that thiosulfate is a metabolically important product of this processes. Hydrogen sulfide oxidation by ferric hemoglobin, myoglobin and neuroglobin has been defined as a non-canonical hydrogen sulfide oxidation pathway. Until recently, it appeared that the goal of thiosulfate production was to delay irreversible oxidation of hydrogen sulfide to sulfate excreted in urine; while thiosulfate itself was only an intermediate, transient metabolite on the hydrogen sulfide oxidation pathway. In the light of data presented in this paper, it seems that thiosulfate is a molecule that plays a prominent role in the human body. Thus, we hope that all these findings will encourage further studies on the role of hemoproteins in the formation of this undoubtedly fascinating molecule and on the mechanisms responsible for its biological activity in the human body.

The Effects of Different Garlic-Derived Allyl Sulfides on Anaerobic Sulfur Metabolism in the Mouse Kidney.

Diallyl sulfide (DAS), diallyl disulfide (DADS) and diallyl trisulfide (DATS) are major oil-soluble organosulfur compounds of garlic responsible for most of its pharmacological effects. The present study investigated the influence of repeated intraperitoneally (ip) administration of DAS, DADS and DATS on the total level of sulfane sulfur, bound sulfur (S-sulfhydration) and hydrogen sulfide (H2S) and on the activity of enzymes, which catalyze sulfane sulfur formation and transfer from a donor to an acceptor in the normal mouse kidney, i.e., γ-cystathionase (CSE) and rhodanese (TST). The activity of aldehyde dehydrogenase (ALDH), which is a redox-sensitive protein, containing an -SH group in its catalytic center, was also determined. The obtained results indicated that all tested compounds significantly increased the activity of TST. Moreover, DADS and DATS increased the total sulfane sulfur level and CSE activity in the normal mouse kidney. ALDH activity was inhibited in the kidney after DATS administration. The results indicated also that none of the studied allyl sulfides affected the level of bound sulfur or H2S. Thus, it can be concluded that garlic-derived DADS and DATS can be a source of sulfane sulfur for renal cells but they are not connected with persulfide formation.

Cysteine Metabolism and Oxidative Processes in the Rat Liver and Kidney after Acute and Repeated Cocaine Treatment.

The role of cocaine in modulating the metabolism of sulfur-containing compounds in the peripheral tissues is poorly understood. In the present study we addressed the question about the effects of acute and repeated (5 days) cocaine (10 mg/kg i.p.) administration on the total cysteine (Cys) metabolism and on the oxidative processes in the rat liver and kidney. The whole pool of sulfane sulfur, its bound fraction and hydrogen sulfide (H2S) were considered as markers of anaerobic Cys metabolism while the sulfate as a measure of its aerobic metabolism. The total-, non-protein- and protein- SH group levels were assayed as indicators of the redox status of thiols. Additionally, the activities of enzymes involved in H2S formation (cystathionine γ-lyase, CSE; 3-mercaptopyruvate sulfurtransferase, 3-MST) and GSH metabolism (γ-glutamyl transpeptidase, γ-GT; glutathione S-transferase, GST) were determined. Finally, we assayed the concentrations of reactive oxygen species (ROS) and malondialdehyde (MDA) as markers of oxidative stress and lipid peroxidation, respectively. In the liver, acute cocaine treatment, did not change concentrations of the whole pool of sulfane sulfur, its bound fraction, H2S or sulfate but markedly decreased levels of non-protein SH groups (NPSH), ROS and GST activity while γ-GT was unaffected. In the kidney, acute cocaine significantly increased concentration of the whole pool of sulfane sulfur, reduced the content of its bound fraction but H2S, sulfate and NPSH levels were unchanged while ROS and activities of GST and γ-GT were reduced. Acute cocaine enhanced activity of the CSE and 3-MST in the liver and kidney, respectively. Repeatedly administered cocaine enhanced the whole pool of sulfane sulfur and reduced H2S level simultaneously increasing sulfate content both in the liver and kidney. After repeated cocaine, a significant decrease in ROS was still observed in the liver while in the kidney, despite unchanged ROS content, a marked increase in MDA level was visible. The repeated cocaine decreased 3-MST and increased γ-GT activities in both organs but reduced GST in the kidney. Our results show that cocaine administered at a relatively low dose shifts Cys metabolism towards the formation of sulfane sulfur compounds which possess antioxidant and redox regulatory properties and are a source of H2S which can support mitochondrial bioenergetics.

S-sulfhydration as a cellular redox regulation.

For many years reactive oxygen and nitrogen species (ROS and RNS) have been recognized as key messengers in the process of thiol-based redox regulation. Relatively recently, literature reports began to mention reactive sulfur species (RSS) and their role in thiol regulation. This review is focused on biogenesis and biological properties of RSS, including: hydropersulfides, polysulfides and hydrogen sulfide (H2S). Based on the most up-to-date literature data, the paper presents biological significance of S-sulfhydration process. In this reaction, sulfane sulfur is transferred to the-SH groups forming hydropersulfides. Protein cysteine residues, called 'redox switches' are susceptible to such reversible modifications. In line with the most recent reports, it was emphasized that sulfane sulfur-containing compounds (mainly hydrogen persulfides and polysulfides) are real and better mediators of S-sulfhydration-based signalling than H2S. We also overviewed proteins participating in the formation and transport of RSS and in mitochondrial H2S oxidation. In addition, we reviewed many reports about proteins unrelated to sulfur metabolism which are modified by S-sulfhydration that influences their catalytic activity. We also addressed the problem of the regulatory function of S-sulfhydration reaction in the activation of KATP channels (vasorelaxant) and transcription factors (e.g. NFκB) as well as in the mechanism of therapeutic action of garlic-derived sulfur compounds. Some aspects of comparison between RNS and RSS are also discussed in this review.