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1.
BMC Nephrol ; 22(1): 250, 2021 07 05.
Article in English | MEDLINE | ID: mdl-34225671

ABSTRACT

BACKGROUND: Taurine depletion occurs in patients with end-stage chronic kidney disease (CKD). In contrast, in the absence of CKD, plasma taurine is reported to increase following dietary L-glutamine supplementation. This study tested the hypothesis that taurine biosynthesis decreases in a rat CKD model, but is rectified by L-glutamine supplementation. METHODS: CKD was induced by partial nephrectomy in male Sprague-Dawley rats, followed 2 weeks later by 2 weeks of 12% w/w L-glutamine supplemented diet (designated NxT) or control diet (NxC). Sham-operated control rats (S) received control diet. RESULTS: Taurine concentration in plasma, liver and skeletal muscle was not depleted, but steady-state urinary taurine excretion (a measure of whole-body taurine biosynthesis) was strongly suppressed (28.3 ± 8.7 in NxC rats versus 78.5 ± 7.6 µmol/24 h in S, P < 0.05), accompanied by reduced taurine clearance (NxC 0.14 ± 0.05 versus 0.70 ± 0.11 ml/min/Kg body weight in S, P < 0.05). Hepatic expression of mRNAs encoding key enzymes of taurine biosynthesis (cysteine sulphinic acid decarboxylase (CSAD) and cysteine dioxygenase (CDO)) showed no statistically significant response to CKD (mean relative expression of CSAD and CDO in NxC versus S was 0.91 ± 0.18 and 0.87 ± 0.14 respectively). Expression of CDO protein was also unaffected. However, CSAD protein decreased strongly in NxC livers (45.0 ± 16.8% of that in S livers, P < 0.005). L-glutamine supplementation failed to rectify taurine biosynthesis or CSAD protein expression, but worsened CKD (proteinuria in NxT 12.5 ± 1.2 versus 6.7 ± 1.5 mg/24 h in NxC, P < 0.05). CONCLUSION: In CKD, hepatic CSAD is depleted and taurine biosynthesis impaired. This is important in view of taurine's reported protective effect against cardio-vascular disease - the leading cause of death in human CKD.


Subject(s)
Carboxy-Lyases/metabolism , Dietary Supplements , Glutamine/administration & dosage , Liver/enzymology , Renal Insufficiency, Chronic/metabolism , Taurine/biosynthesis , Animals , Cysteine Dioxygenase/metabolism , Disease Models, Animal , Humans , Liver/metabolism , Male , Muscle, Skeletal/metabolism , Nephrectomy , Proteinuria , RNA, Messenger/metabolism , Rats, Sprague-Dawley , Renal Insufficiency, Chronic/diet therapy , Taurine/metabolism
2.
Int J Mol Sci ; 22(11)2021 May 30.
Article in English | MEDLINE | ID: mdl-34070749

ABSTRACT

Atherosclerosis and nonalcoholic fatty liver disease are leading causes of morbidity and mortality in the Western countries. The renin-angiotensin system (RAS) with its two main opposing effectors, i.e., angiotensin II (Ang II) and Ang-(1-7), is widely recognized as a major regulator of cardiovascular function and body metabolic processes. Angiotensin-converting enzyme 2 (ACE2) by breaking-down Ang II forms Ang-(1-7) and thus favors Ang-(1-7) actions. Therefore, the aim of our study was to comprehensively evaluate the influence of prolonged treatment with ACE2 activator, diminazene aceturate (DIZE) on the development of atherosclerotic lesions and hepatic steatosis in apoE-/- mice fed a high-fat diet (HFD). We have shown that DIZE stabilized atherosclerotic lesions and attenuated hepatic steatosis in apoE-/- mice fed an HFD. Such effects were associated with decreased total macrophages content and increased α-smooth muscle actin levels in atherosclerotic plaques. Moreover, DIZE changed polarization of macrophages towards increased amount of anti-inflammatory M2 macrophages in the atherosclerotic lesions. Interestingly, the anti-steatotic action of DIZE in the liver was related to the elevated levels of HDL in the plasma, decreased levels of triglycerides, and increased biosynthesis and concentration of taurine in the liver of apoE-/- mice. However, exact molecular mechanisms of both anti-atherosclerotic and anti-steatotic actions of DIZE require further investigations.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Atherosclerosis/drug therapy , Diminazene/analogs & derivatives , Fatty Liver/drug therapy , Plaque, Atherosclerotic/drug therapy , Taurine/biosynthesis , Angiotensin I/genetics , Angiotensin I/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Animals , Apolipoproteins E/deficiency , Apolipoproteins E/genetics , Atherosclerosis/etiology , Atherosclerosis/genetics , Atherosclerosis/pathology , Diet, High-Fat , Diminazene/pharmacology , Disease Models, Animal , Fatty Liver/etiology , Fatty Liver/genetics , Fatty Liver/pathology , Female , Gene Expression Regulation , Humans , Liver/drug effects , Liver/metabolism , Liver/pathology , Macrophage Activation , Macrophages/drug effects , Macrophages/metabolism , Macrophages/pathology , Mesenteric Arteries/drug effects , Mesenteric Arteries/metabolism , Mesenteric Arteries/pathology , Mice , Mice, Inbred C57BL , Mice, Knockout, ApoE , Peptide Fragments/genetics , Peptide Fragments/metabolism , Plaque, Atherosclerotic/etiology , Plaque, Atherosclerotic/genetics , Plaque, Atherosclerotic/pathology , THP-1 Cells , Taurine/agonists
3.
Oxid Med Cell Longev ; 2020: 8294158, 2020.
Article in English | MEDLINE | ID: mdl-33062147

ABSTRACT

Sulfur contributes significantly to nature chemical diversity and thanks to its particular features allows fundamental biological reactions that no other element allows. Sulfur natural compounds are utilized by all living beings and depending on the function are distributed in the different kingdoms. It is no coincidence that marine organisms are one of the most important sources of sulfur natural products since most of the inorganic sulfur is metabolized in ocean environments where this element is abundant. Terrestrial organisms such as plants and microorganisms are also able to incorporate sulfur in organic molecules to produce primary metabolites (e.g., methionine, cysteine) and more complex unique chemical structures with diverse biological roles. Animals are not able to fix inorganic sulfur into biomolecules and are completely dependent on preformed organic sulfurous compounds to satisfy their sulfur needs. However, some higher species such as humans are able to build new sulfur-containing chemical entities starting especially from plants' organosulfur precursors. Sulfur metabolism in humans is very complicated and plays a central role in redox biochemistry. The chemical properties, the large number of oxidation states, and the versatile reactivity of the oxygen family chalcogens make sulfur ideal for redox biological reactions and electron transfer processes. This review will explore sulfur metabolism related to redox biochemistry and will describe the various classes of sulfur-containing compounds spread all over the natural kingdoms. We will describe the chemistry and the biochemistry of well-known metabolites and also of the unknown and poorly studied sulfur natural products which are still in search for a biological role.


Subject(s)
Sulfur Compounds/metabolism , Animals , Cysteine/metabolism , Glutathione/metabolism , Glycoside Hydrolases/metabolism , Humans , Methionine/metabolism , Oxidation-Reduction , Plants/chemistry , Plants/metabolism , Sulfur Compounds/chemistry , Taurine/biosynthesis , Taurine/chemistry
4.
Drug Metab Dispos ; 48(5): 378-385, 2020 05.
Article in English | MEDLINE | ID: mdl-32156684

ABSTRACT

Taurine is one of the most abundant amino acids in mammalian tissues. It is obtained from the diet and by de novo synthesis from cysteic acid or hypotaurine. Despite the discovery in 1954 that the oxygenation of hypotaurine produces taurine, the identification of an enzyme catalyzing this reaction has remained elusive. In large part, this is due to the incorrect assignment, in 1962, of the enzyme as an NAD-dependent hypotaurine dehydrogenase. For more than 55 years, the literature has continued to refer to this enzyme as such. Here we show, both in vivo and in vitro, that the enzyme that oxygenates hypotaurine to produce taurine is flavin-containing monooxygenase (FMO) 1. Metabolite analysis of the urine of Fmo1-null mice by 1H NMR spectroscopy revealed a buildup of hypotaurine and a deficit of taurine in comparison with the concentrations of these compounds in the urine of wild-type mice. In vitro assays confirmed that human FMO1 catalyzes the conversion of hypotaurine to taurine, utilizing either NADPH or NADH as cofactor. FMO1 has a wide substrate range and is best known as a xenobiotic- or drug-metabolizing enzyme. The identification that the endogenous molecule hypotaurine is a substrate for the FMO1-catalyzed production of taurine resolves a long-standing mystery. This finding should help establish the role FMO1 plays in a range of biologic processes in which taurine or its deficiency is implicated, including conjugation of bile acids, neurotransmitter, antioxidant and anti-inflammatory functions, and the pathogenesis of obesity and skeletal muscle disorders. SIGNIFICANCE STATEMENT: The identity of the enzyme that catalyzes the biosynthesis of taurine from hypotaurine has remained elusive. Here we show, both in vivo and in vitro, that flavin-containing monooxygenase 1 catalyzes the oxygenation of hypotaurine to produce taurine.


Subject(s)
Oxygenases/metabolism , Taurine/analogs & derivatives , Taurine/biosynthesis , Animals , Biocatalysis , Female , Male , Mice , Mice, Knockout , NAD/metabolism , NADP/metabolism , Oxygenases/genetics , Proton Magnetic Resonance Spectroscopy , Taurine/metabolism
5.
Biochem J ; 476(15): 2271-2279, 2019 08 15.
Article in English | MEDLINE | ID: mdl-31350331

ABSTRACT

Aminoethylsulfonate (taurine) is widespread in the environment and highly abundant in the human body. Taurine and other aliphatic sulfonates serve as sulfur sources for diverse aerobic bacteria, which carry out cleavage of the inert sulfonate C-S bond through various O2-dependent mechanisms. Taurine also serves as a sulfur source for certain strict anaerobic fermenting bacteria. However, the mechanism of C-S cleavage by these bacteria has long been a mystery. Here we report the biochemical characterization of an anaerobic pathway for taurine sulfur assimilation in a strain of Clostridium butyricum from the human gut. In this pathway, taurine is first converted to hydroxyethylsulfonate (isethionate), followed by C-S cleavage by the O2-sensitive isethionate sulfo-lyase IseG, recently identified in sulfate- and sulfite-reducing bacteria. Homologs of the enzymes described in this study have a sporadic distribution in diverse strict and facultative anaerobic bacteria, from both the environment and the taurine-rich human gut, and may enable sulfonate sulfur acquisition in certain nutrient limiting conditions.


Subject(s)
Bacterial Proteins , Clostridium butyricum , Gastrointestinal Microbiome , Intestines/microbiology , Multigene Family , Taurine , Anaerobiosis , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Clostridium butyricum/genetics , Clostridium butyricum/metabolism , Humans , Isethionic Acid/metabolism , Sulfates/metabolism , Taurine/biosynthesis , Taurine/genetics
6.
J Anim Sci ; 97(3): 983-997, 2019 03 01.
Article in English | MEDLINE | ID: mdl-30615118

ABSTRACT

In July 2018, the Food and Drug Administration warned about a possible relationship between dilated cardiomyopathy (DCM) in dogs and the consumption of dog food formulated with potatoes and pulse ingredients. This issue may impede utilization of pulse ingredients in dog food or consideration of alternative proteins. Pulse ingredients have been used in the pet food industry for over 2 decades and represent a valuable source of protein to compliment animal-based ingredients. Moreover, individual ingredients used in commercial foods do not represent the final nutrient concentration of the complete diet. Thus, nutritionists formulating dog food must balance complementary ingredients to fulfill the animal's nutrient needs in the final diet. There are multiple factors that should be considered, including differences in nutrient digestibility and overall bioavailability, the fermentability and quantity of fiber, and interactions among food constituents that can increase the risk of DCM development. Taurine is a dispensable amino acid that has been linked to DCM in dogs. As such, adequate supply of taurine and/or precursors for taurine synthesis plays an important role in preventing DCM. However, requirements of amino acids in dogs are not well investigated and are presented in total dietary content basis which does not account for bioavailability or digestibility. Similarly, any nutrient (e.g., soluble and fermentable fiber) or physiological condition (e.g., size of the dog, sex, and age) that increases the requirement for taurine will also augment the possibility for DCM development. Dog food formulators should have a deep knowledge of processing methodologies and nutrient interactions beyond meeting the Association of American Feed Control Officials nutrient profiles and should not carelessly follow unsubstantiated market trends. Vegetable ingredients, including pulses, are nutritious and can be used in combination with complementary ingredients to meet the nutritional needs of the dog.


Subject(s)
Cardiomyopathy, Dilated/veterinary , Dietary Fiber/adverse effects , Dog Diseases/etiology , Fabaceae/adverse effects , Amino Acids/administration & dosage , Amino Acids/metabolism , Animal Feed , Animal Nutritional Physiological Phenomena , Animals , Biological Availability , Breeding , Cardiomyopathy, Dilated/etiology , Cicer/adverse effects , Diet/adverse effects , Diet/veterinary , Dogs , Heart Rate , Lens Plant/adverse effects , Nutritional Requirements , Pisum sativum/adverse effects , Taurine/biosynthesis , Taurine/deficiency
7.
Int J Biochem Cell Biol ; 107: 116-127, 2019 02.
Article in English | MEDLINE | ID: mdl-30593952

ABSTRACT

Development of resistance poses a significant challenge to effective first-line platinum based therapy for epithelial ovarian cancer patients. Cancer Stem Cells are envisaged as a critical underlying factor for therapy resistance. Thus, there is a critical need for developing approaches to diminish the enrichment of cancer stem cells and acquirement of resistance. Administration of metformin, a commonly prescribed drug against Type II diabetes exhibited promising effect in the management of ovarian cancer. However, the effect of long term administration of low dose of metformin as an adjuvant to cisplatin and paclitaxel during acquirement of chemoresistant phenotype has not been investigated so far. Using two isogenic cellular chemoresistant models (A2780 and OAW42) developed in the presence or absence of metformin, we demonstrated the ability of metformin to impede the development of resistance through increased drug sensitivity, increased proliferation, and reduced migratory abilities of the resistant cells. Metformin introduction also decreased the cancer stem cell population, expression of specific biomarkers and pluripotent genes. Further metabolic profiling of these cells using 1H-Nuclear Magnetic Resonance spectroscopy revealed significant modulation in taurine and histidine levels in resistant cells developed in the presence of metformin. Intriguingly, taurine treatment considerably reduced the cancer stem cell population and chemoresistance in resistant cells, indicating a novel role of taurine in differentiation of ovarian cancer stem cells. Altogether this is the first report on the potential role of metformin for targeting the cancer stem cell population via up regulation of taurine, leading to impediment in the acquirement of chemoresistance.


Subject(s)
Cell Differentiation/drug effects , Drug Resistance, Neoplasm/drug effects , Metformin/pharmacology , Neoplastic Stem Cells/drug effects , Ovarian Neoplasms/pathology , Taurine/biosynthesis , Amino Acids/metabolism , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cisplatin/pharmacology , Female , Humans , Neoplastic Stem Cells/metabolism , Neoplastic Stem Cells/pathology , Paclitaxel/pharmacology , Time Factors
8.
J Agric Food Chem ; 66(51): 13454-13463, 2018 Dec 26.
Article in English | MEDLINE | ID: mdl-30516051

ABSTRACT

Taurine is a biologically and physiologically valuable food additive. However, commercial taurine production mainly relies on environmentally harmful chemical synthesis. Herein, for the first time in bacteria, we attempted to produce taurine in metabolically engineered Corynebacterium glutamicum. The taurine-producing strain was developed by introducing cs, cdo1, and csad genes. Interestingly, while the control strain could not produce taurine, the engineered strains successfully produced taurine via the newly introduced metabolic pathway. Furthermore, we investigated the effect of a deletion strain of the transcriptional repressor McbR gene on taurine production. As a result, sulfur accumulation and l-cysteine biosynthesis were reinforced by the McbR deletion strain, which further increased the taurine production by 2.3-fold. Taurine production of the final engineered strain Tau11 was higher than in other previously reported strains. This study demonstrated a potential approach for eco-friendly biosynthesis as an alternative to the chemical synthesis of a food additive.


Subject(s)
Corynebacterium glutamicum/genetics , Corynebacterium glutamicum/metabolism , Food Additives/metabolism , Metabolic Engineering , Taurine/biosynthesis , Fermentation , Metabolic Networks and Pathways
9.
Life Sci ; 186: 80-86, 2017 Oct 01.
Article in English | MEDLINE | ID: mdl-28801262

ABSTRACT

Obesity is caused by an imbalance between energy intake and energy expenditure. It is established that obesity is a state of low-grade chronic inflammation, which is characterized by enlarged hypertrophied adipocytes, increased infiltration by macrophages and marked changes in the secretion of adipokines and free fatty acids. The effects of taurine on the pathogenesis of obesity have been reported in animals and humans. Although the mechanisms underlying the anti-obesity action of taurine remain to be defined, taurine seems to ameliorate obesity through stimulation of energy expenditure, modulation of lipid metabolism, anorexic effect, anti-inflammatory and anti-oxidative effects. Recent studies revealed that taurine supplementation reduces the infiltration of macrophages and modulates the polarization of adipose tissue macrophages in high-fat diet-induced obese mice. In addition, taurine downregulates the production of pro-inflammatory cytokines by adipocytes, suggesting that taurine plays an anti-inflammatory role in adipose tissue. This article reviews the effects and mechanisms of taurine on the development of obesity, focusing on the role of taurine in white adipose tissue.


Subject(s)
Adipose Tissue/drug effects , Energy Metabolism/drug effects , Lipid Metabolism/drug effects , Obesity/etiology , Taurine , Adipokines/metabolism , Adipose Tissue/immunology , Adipose Tissue/metabolism , Animals , Diet, High-Fat , Humans , Obesity/immunology , Obesity/metabolism , Obesity/prevention & control , Taurine/biosynthesis , Taurine/pharmacology
10.
Adv Exp Med Biol ; 975 Pt 2: 729-740, 2017.
Article in English | MEDLINE | ID: mdl-28849495

ABSTRACT

There has been a growing interest on the effects of radiation since the Fukushima nuclear power plant accident of 2011. Taurine has been reported to have a radioprotective effect in irradiated mice. However, the detailed mechanism of this radioprotective effect is still awaiting clarification. The aim of this study was to investigation how radiation affects the expression of taurine and to shed light on the mechanism accounting for radioprotective and radiation mitigating effect. Six-week-old male mice were randomly divided into two groups: IR group (7 Gy irradiation) and IR + Tau group (7 Gy irradiation + taurine 3000 mg/kg/day). We examined the survival rate, the expression of taurine and taurine transporter in the small intestine and the urinary taurine concentration. In this study, no statistically significant difference was found in the survival rate between IR Group and IR + Tau Group. Three days and 7 days after irradiation, the urinary taurine concentration of IR + Tau group increased more than that of IR group. Three days and 10 days after irradiation, the expression of taurine and taurine transporter in the small intestine of IR group and IR + Tau group decreased more than that of normal small intestine. It is reported that radiation exposure increases the urinary taurine concentration. We found that the radiation exposure decreases the expression of the taurine transporter in the small intestine of mouse. This finding suggests that a decrease in the expression of the taurine transporter promotes the release of taurine from the tissue into the urine.


Subject(s)
Intestine, Small/metabolism , Intestine, Small/radiation effects , Membrane Glycoproteins/biosynthesis , Membrane Transport Proteins/biosynthesis , Radiation Injuries, Experimental/metabolism , Whole-Body Irradiation/adverse effects , Animals , Male , Mice , Mice, Inbred ICR , Taurine/biosynthesis , Taurine/urine
11.
Sci Rep ; 7(1): 5505, 2017 07 14.
Article in English | MEDLINE | ID: mdl-28710376

ABSTRACT

Taurine has been reported high amounts in marine animals to maintain osmotic balance between osmoformers and sea water. Approximately 80% of the total amino-acid content is taurine in Pacific oyster Crassostrea gigas, an intertidal and euryhaline species. In this study, we cloned the two copies of cysteine sulfinate decarboxylase (CSAD), the key enzyme in taurine biosynthesis pathway, screened in oyster genome data. Sequentially, we compared the expression patterns of CgCSAD1 and CgCSAD2 under low salinity treatment (8‰ and 15‰) using different families from two populations. There was no correlation between the expression of CSAD and the different population. Notably, CgCSAD1 increased significantly in treated groups for 24 h, but CgCSAD2 had no significant differentiation. Moreover, the results of CgCSAD1 interference provided the evidence of the positive correlation between CgCSAD1 expressions and taurine contents. The zinc finger domain showed in multi-alignment results may be the important character of CgCSAD1 as the key enzyme in taurine biosynthesis to regulate taurine pool in response to low salinity. This study provides a new evidence for the important role of taurine in adaptation to low salinity in oyster. In addition, it is a good model to discuss the function and evolution of the duplication in mollusks.


Subject(s)
Carboxy-Lyases/genetics , Carboxy-Lyases/metabolism , Crassostrea/enzymology , Taurine/biosynthesis , Animals , Carboxy-Lyases/chemistry , Cloning, Molecular , Crassostrea/genetics , Evolution, Molecular , Gene Duplication , Gene Expression Regulation, Enzymologic , Salinity , Zinc Fingers
12.
Mar Drugs ; 15(6)2017 May 25.
Article in English | MEDLINE | ID: mdl-28587087

ABSTRACT

Although taurine has been shown to play multiple important physiological roles in teleosts, little is known about the molecular mechanisms underlying dietary requirements. Cell lines can provide useful tools for deciphering biosynthetic pathways and their regulation. However, culture media and sera contain variable taurine levels. To provide a useful cell line for the investigation of taurine homeostasis, an adult zebrafish liver cell line (ZFL) has been adapted to a taurine-free medium by gradual accommodation to a commercially available synthetic medium, UltraMEM™-ITES. Here we show that ZFL cells are able to synthesize taurine and be maintained in medium without taurine. This has allowed for the investigation of the effects of taurine supplementation on cell growth, cellular amino acid pools, as well as the expression of the taurine biosynthetic pathway and taurine transporter genes in a defined fish cell type. After taurine supplementation, cellular taurine levels increase but hypotaurine levels stay constant, suggesting little suppression of taurine biosynthesis. Cellular methionine levels do not change after taurine addition, consistent with maintenance of taurine biosynthesis. The addition of taurine to cells grown in taurine-free medium has little effect on transcript levels of the biosynthetic pathway genes for cysteine dioxygenase (CDO), cysteine sulfinate decarboxylase (CSAD), or cysteamine dioxygenase (ADO). In contrast, supplementation with taurine causes a 30% reduction in transcript levels of the taurine transporter, TauT. This experimental approach can be tailored for the development of cell lines from aquaculture species for the elucidation of their taurine biosynthetic capacity.


Subject(s)
Culture Media, Serum-Free/metabolism , Liver/metabolism , Taurine/biosynthesis , Taurine/metabolism , Zebrafish/metabolism , Amino Acids/metabolism , Animals , Carboxy-Lyases/metabolism , Cell Line , Cysteine Dioxygenase/metabolism , Dioxygenases/metabolism , Membrane Glycoproteins/metabolism , Membrane Transport Proteins/metabolism , Taurine/analogs & derivatives
13.
Mol Cell Biochem ; 416(1-2): 11-22, 2016 May.
Article in English | MEDLINE | ID: mdl-27023909

ABSTRACT

Hyper-beta-alaninemia is a rare metabolic condition that results in elevated plasma and urinary ß-alanine levels and is characterized by neurotoxicity, hypotonia, and respiratory distress. It has been proposed that at least some of the symptoms are caused by oxidative stress; however, only limited information is available on the mechanism of reactive oxygen species generation. The present study examines the hypothesis that ß-alanine reduces cellular levels of taurine, which are required for normal respiratory chain function; cellular taurine depletion is known to reduce respiratory function and elevate mitochondrial superoxide generation. To test the taurine hypothesis, isolated neonatal rat cardiomyocytes and mouse embryonic fibroblasts were incubated with medium lacking or containing ß-alanine. ß-alanine treatment led to mitochondrial superoxide accumulation in conjunction with a decrease in oxygen consumption. The defect in ß-alanine-mediated respiratory function was detected in permeabilized cells exposed to glutamate/malate but not in cells utilizing succinate, suggesting that ß-alanine leads to impaired complex I activity. Taurine treatment limited mitochondrial superoxide generation, supporting a role for taurine in maintaining complex I activity. Also affected by taurine is mitochondrial morphology, as ß-alanine-treated fibroblasts undergo fragmentation, a sign of unhealthy mitochondria that is reversed by taurine treatment. If left unaltered, ß-alanine-treated fibroblasts also undergo mitochondrial apoptosis, as evidenced by activation of caspases 3 and 9 and the initiation of the mitochondrial permeability transition. Together, these data show that ß-alanine mediates changes that reduce ATP generation and enhance oxidative stress, factors that contribute to heart failure.


Subject(s)
Disorders of Excessive Somnolence/metabolism , Mitochondria, Heart/metabolism , Mitochondrial Diseases/metabolism , Myocytes, Cardiac/metabolism , Seizures/metabolism , beta-Alanine/metabolism , beta-Alanine/toxicity , Animals , Disorders of Excessive Somnolence/genetics , Disorders of Excessive Somnolence/pathology , Electron Transport Complex I/genetics , Electron Transport Complex I/metabolism , Embryo, Mammalian/metabolism , Embryo, Mammalian/pathology , Fibroblasts/metabolism , Fibroblasts/pathology , Mice , Mitochondria, Heart/genetics , Mitochondria, Heart/pathology , Mitochondrial Diseases/genetics , Mitochondrial Diseases/pathology , Myocytes, Cardiac/pathology , Oxygen Consumption , Rats , Seizures/genetics , Seizures/pathology , Taurine/biosynthesis , Taurine/genetics , beta-Alanine/genetics
14.
Sci Rep ; 6: 21231, 2016 Feb 16.
Article in English | MEDLINE | ID: mdl-26880478

ABSTRACT

Animals have varied taurine biosynthesis capability, which was determined by activities of key enzymes including cysteine dioxygenase (CDO) and cysteine sulfinate decarboxylase (CSD). However, whether CDO and CSD are differentially regulated across species remains unexplored. In the present study, we examined the regulations of CDO and CSD in rainbow trout and Japanese flounder, the two fish species with high and low taurine biosynthesis ability respectively. Our results showed that the expression of CDO was lower in rainbow trout but more responsive to cysteine stimulation compared to that in Japanese flounder. On the other hand, both the expression and catalytic efficiency (k(cat)) of CSD were higher in rainbow trout than those of Japanese flounder. A three-residue substrate recognition motif in rainbow trout CSD with sequence of F126/S146/Y148 was identified to be responsible for high k(cat), while that with sequence of F88/N108/F110 in Japanese flounder led to low k(cat), as suggested by site-directed mutagenesis studies. In summary, our results determined new aspects of taurine biosynthesis regulation across species.


Subject(s)
Flounder/metabolism , Oncorhynchus mykiss/metabolism , Taurine/biosynthesis , Amino Acid Sequence , Animals , Carboxy-Lyases/genetics , Carboxy-Lyases/metabolism , Cloning, Molecular , Cysteine Dioxygenase/genetics , Cysteine Dioxygenase/metabolism , DNA, Complementary , Enzyme Activation , Flounder/genetics , Gene Expression , Liver/metabolism , Oncorhynchus mykiss/genetics , Sequence Analysis, DNA
15.
J Physiol ; 594(11): 3095-110, 2016 06 01.
Article in English | MEDLINE | ID: mdl-26659826

ABSTRACT

KEY POINTS: Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease associated with increased inflammation, oxidative stress and myofibre necrosis. Cysteine precursor antioxidants such as N-acetyl cysteine (NAC) and l-2-oxothiazolidine-4-carboxylate (OTC) reduce dystropathology in the mdx mouse model for DMD, and we propose this is via increased synthesis of the amino acid taurine. We compared the capacity of OTC and taurine treatment to increase taurine content of mdx muscle, as well as effects on in vivo and ex vivo muscle function, inflammation and oxidative stress. Both treatments increased taurine in muscles, and improved many aspects of muscle function and reduced inflammation. Taurine treatment also reduced protein thiol oxidation and was overall more effective, as OTC treatment reduced body and muscle weight, suggesting some adverse effects of this drug. These data suggest that increasing dietary taurine is a better candidate for a therapeutic intervention for DMD. ABSTRACT: Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease for which there is no widely available cure. Whilst the mechanism of loss of muscle function in DMD and the mdx mouse model are not fully understood, disruptions in intracellular calcium homeostasis, inflammation and oxidative stress are implicated. We have shown that protein thiol oxidation is increased in mdx muscle, and that the indirect thiol antioxidant l-2-oxothiazolidine-4-carboxylate (OTC), which increases cysteine availability, decreases pathology and increases in vivo strength. We propose that the protective effects of OTC are a consequence of conversion of cysteine to taurine, which has itself been shown to be beneficial to mdx pathology. This study compares the efficacy of taurine with OTC in decreasing dystropathology in mdx mice by measuring in vivo and ex vivo contractile function and measurements of inflammation and protein thiol oxidation. Increasing the taurine content of mdx muscle improved both in vivo and ex vivo muscle strength and function, potentially via anti-inflammatory and antioxidant effects of taurine. OTC treatment increased taurine synthesis in the liver and taurine content of mdx muscle, improved muscle function and decreased inflammation. However, OTC was less effective than taurine treatment, with OTC also decreasing body and EDL muscle weights, suggesting that OTC had some detrimental effects. These data support continued research into the use of taurine as a therapeutic intervention for DMD, and suggest that increasing dietary taurine is the better strategy for increasing taurine content and decreasing severity of dystropathology.


Subject(s)
Muscle, Skeletal/drug effects , Muscle, Skeletal/physiology , Muscular Dystrophy, Duchenne/diet therapy , Muscular Dystrophy, Duchenne/metabolism , Taurine/administration & dosage , Taurine/biosynthesis , Animals , Disease Models, Animal , Female , Male , Mice , Mice, Inbred C57BL , Mice, Inbred mdx , Muscle Contraction/drug effects , Muscle Contraction/physiology , Muscular Dystrophy, Duchenne/genetics , Pyrrolidonecarboxylic Acid/administration & dosage , Thiazolidines/administration & dosage
18.
Amino Acids ; 47(6): 1273-7, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25833720

ABSTRACT

We determined the alterations in metabolic conversion of cysteine into glutathione and taurine in liver of rats treated with ethanol acutely. Ethanol treatment reduced cysteine as well as glutathione levels in liver for 24 h. However, cysteine dioxygenase was up-regulated rapidly, and hypotaurine/taurine levels were significantly higher than those found in the saline-treated rats. It is therefore suggested that enhancement of cysteine catabolism into taurine contributes to the depletion of hepatic glutathione, which could exacerbate the ethanol-induced oxidative liver injury.


Subject(s)
Cysteine/metabolism , Ethanol/pharmacology , Glutathione/metabolism , Liver/metabolism , Taurine/biosynthesis , Animals , Male , Rats , Rats, Sprague-Dawley
19.
Article in English | MEDLINE | ID: mdl-25773436

ABSTRACT

Taurine (2-aminoethane sulfonic acid) plays important roles in multiple physiological processes including osmoregulation, bile salt conjugation and membrane protection. It is known that taurine biosynthesis varies in different fish species. However, its ontogenetic regulation has not been clear. In the present study, we found that the hepatic concentrations of taurine increased marginally with rainbow trout growth. The mRNA expression, protein levels and enzyme activities of key enzymes involved in taurine biosynthesis, cysteine dioxygenase (CDO) and cysteine sulfinate decarboxylase (CSD), were analyzed. Our results showed that the mRNA levels and protein abundances of CSD increased dramatically with the development of rainbow trout stages while the enzyme activities showed a slight improvement. However, the expression and activities of CDO decreased with rainbow trout growth. These results provide valuable information on defining the exact supplementation of taurine in diets for different stages of rainbow trout and give new insights into elucidating the regulation of taurine metabolism in rainbow trout.


Subject(s)
Morphogenesis , Oncorhynchus mykiss/growth & development , Oncorhynchus mykiss/metabolism , Taurine/biosynthesis , Animals , Body Size , Carboxy-Lyases/genetics , Cysteine Dioxygenase/genetics , Gene Expression Regulation, Developmental , Liver/enzymology , Liver/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism
20.
Amino Acids ; 47(6): 1215-23, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25772816

ABSTRACT

Our investigation showed that hepatocytes isolated from cysteine dioxygenase knockout mice (Cdo1(-/-)) had lower levels of hypotaurine and taurine than Cdo1 (+/+) hepatocytes. Interestingly, hypotaurine accumulates in cultured wild-type hepatocytes. DL-propargylglycine (PPG, inhibitor of cystathionine γ-lyase and H2S production) dramatically decreased both taurine and hypotaurine levels in wild-type hepatocytes compared to untreated cells. Addition of 2 mM PPG resulted in the decrease of the intracellular taurine levels: from 10.25 ± 5.00 observed in control, to 2.53 ± 0.68 nmol/mg protein (24 h of culture) and from 17.06 ± 9.40 to 2.43 ± 0.26 nmol/mg protein (control vs. PPG; 48 h). Addition of PPG reduced also intracellular hypotaurine levels: from 7.46 ± 3.55 to 0.31 ± 0.12 nmol/mg protein (control vs. PPG; 24 h) and from 4.54 ± 3.20 to 0.42 ± 0.11 nmol/mg protein (control vs. PPG; 48 h). The similar effects of PPG on hypotaurine and taurine levels were observed in culture medium. PPG blocked hypotaurine/taurine synthesis in wild-type hepatocytes, suggesting that it strongly inhibits cysteinesulfinate decarboxylase (pyridoxal 5'-phosphate-dependent enzyme) as well as cystathionine γ-lyase. In the presence of PPG, intracellular and medium cystathionine levels for both wild-type and Cdo1 (-/-) cells were increased. Addition of homocysteine or methionine resulted in higher intracellular concentrations of homocysteine, which is a cosubstrate for cystathionine ß-synthase (CBS). It seems that PPG increases CBS-mediated desulfhydration by enhancing homocysteine levels in hepatocytes. There were no overall effects of PPG or genotype on intracellular or medium glutathione levels.


Subject(s)
Alkynes/pharmacology , Cystathionine/metabolism , Glycine/analogs & derivatives , Hepatocytes/metabolism , Homocysteine/metabolism , Taurine/analogs & derivatives , Animals , Cells, Cultured , Cystathionine/genetics , Cysteine Dioxygenase/genetics , Cysteine Dioxygenase/metabolism , Female , Glycine/pharmacology , Hepatocytes/cytology , Homocysteine/genetics , Male , Mice , Mice, Knockout , Primary Cell Culture , Taurine/biosynthesis , Taurine/genetics
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