Assimilation of NAD(+) precursors in Candida glabrata

The yeast pathogen Candida glabrata is a nicotinamide adenine dinucleotide (NAD(+)) auxotroph and its growth depends on the environmental supply of vitamin precursors of NAD(+). C. glabrata salvage pathways defined in this article allow NAD(+) to be synthesized from three compounds - nicotinic acid (NA), nicotinamide (NAM) and nicotinamide riboside (NR). NA is salvaged through a functional Preiss-Handler pathway. NAM is first converted to NA by nicotinamidase and then salvaged by the Preiss-Handler pathway. Salvage of NR in C. glabrata occurs via two routes. The first, in which NR is phosphorylated by the NR kinase Nrk1, is independent of the Preiss-Handler pathway. The second is a novel pathway in which NR is degraded by the nucleosidases Pnp1 and Urh1, with a minor role for Meu1, and ultimately converted to NAD(+) via the nicotinamidase Pnc1 and the Preiss-Handler pathway. Using C. glabrata mutants whose growth depends exclusively on the external NA or NR supply, we also show that C. glabrata utilizes NR and to a lesser extent NA as NAD(+) sources during disseminated infection.     

Gut microbiota severely hampers the efficacy of NAD-lowering therapy in leukemia

Most cancer cells have high need for nicotinamide adenine dinucleotide (NAD⁺) to sustain their survival. This led to the development of inhibitors of nicotinamide (NAM) phosphoribosyltransferase (NAMPT), the rate-limiting NAD⁺ biosynthesis enzyme from NAM. Such inhibitors kill cancer cells in preclinical studies but failed in clinical ones. To identify parameters that could negatively affect the therapeutic efficacy of NAMPT inhibitors and propose therapeutic strategies to circumvent such failure, we performed metabolomics analyses in tumor environment and explored the effect of the interaction between microbiota and cancer cells. Here we show that tumor environment enriched in vitamin B3 (NAM) or nicotinic acid (NA) significantly lowers the anti-tumor efficacy of APO866, a prototypic NAMPT inhibitor. Additionally, bacteria (from the gut, or in the medium) can convert NAM into NA and thus fuel an alternative NAD synthesis pathway through NA. This leads to the rescue from NAD depletion, prevents reactive oxygen species production, preserves mitochondrial integrity, blunts ATP depletion, and protects cancer cells from death.Our data in an in vivo preclinical model reveal that antibiotic therapy down-modulating gut microbiota can restore the anti-cancer efficacy of APO866. Alternatively, NAphosphoribosyltransferase inhibition may restore anti-cancer activity of NAMPT inhibitors in the presence of gut microbiota and of NAM in the diet.Subject terms: Drug development, Cancer metabolism

     

Effect of ipriflavone on bone changes induced by calcium restricted, vitamin D deficient diet in rats

The preventive effect of ipriflavone, 7-isopropoxy-isoflavone, on the development of experimental osteopenia in rats was studied. Male Wistar rats (4 weeks old) on a calcium restricted, vitamin D deficient diet were given a daily oral administration of ipriflavone. The administration of ipriflavone (100 mg/kg BW/day) for 40 days significantly inhibited a decrease in the cortical thickness (14.0 +/- 1.6 vs. 17.1 +/- 2.9%, mean +/- SD, p less than 0.05) and bone calcium content (62 +/- 4 vs. 67 +/- 2 mg, p less than 0.05) in the femora of rats induced by a mild calcium restricted (0.3%), vitamin D deficient diet. This compound did not affect serum calcium levels in this condition. But a dose of 20 mg/kg BW/day of ipriflavone was insufficient to inhibit a decrease in bone calcium content. In rats fed on a more severe calcium restricted (0.03%), vitamin D deficient diet, the administration of ipriflavone (100 mg/kg BW/day) did not significantly affect the cortical thickness or calcium content. Intestinal calcium absorption measured by the in situ loop method was not significantly different between rats fed with a severe calcium restricted (0.03%), D deficient diet with or without ipriflavone (20 or 100 mg/kg BW/day) These results demonstrate that the new compound, ipriflavone, partially prevents bone calcium loss induced by a mild calcium restricted (0.3%), vitamin D deficient diet in rats. However, the precise mechanism of action of this compound remains unknown.     

Prevention Effects and Possible Molecular Mechanism of Mulberry Leaf Extract and its Formulation on Rats with Insulin-Insensitivity

For centuries, mulberry leaf has been used in traditional Chinese medicine for the treatment of diabetes. This study aims to test the prevention effects of a proprietary mulberry leaf extract (MLE) and a formula consisting of MLE, fenugreek seed extract, and cinnamon cassia extract (MLEF) on insulin resistance development in animals. MLE was refined to contain 5% 1-deoxynojirimycin by weight. MLEF was formulated by mixing MLE with cinnamon cassia extract and fenugreek seed extract at a 6:5:3 ratio (by weight). First, the acute toxicity effects of MLE on ICR mice were examined at 5 g/kg BW dose. Second, two groups of normal rats were administrated with water or 150 mg/kg BW MLE per day for 29 days to evaluate MLE’s effect on normal animals. Third, to examine the effects of MLE and MLEF on model animals, sixty SD rats were divided into five groups, namely, (1) normal, (2) model, (3) high-dose MLE (75 mg/kg BW) treatment; (4) low-dose MLE (15 mg/kg BW) treatment; and (5) MLEF (35 mg/kg BW) treatment. On the second week, rats in groups (2)-(5) were switched to high-energy diet for three weeks. Afterward, the rats were injected (ip) with a single dose of 105 mg/kg BW alloxan. After four more days, fasting blood glucose, post-prandial blood glucose, serum insulin, cholesterol, and triglyceride levels were measured. Last, liver lysates from animals were screened with 650 antibodies for changes in the expression or phosphorylation levels of signaling proteins. The results were further validated by Western blot analysis. We found that the maximum tolerance dose of MLE was greater than 5 g/kg in mice. The MLE at a 150 mg/kg BW dose showed no effect on fast blood glucose levels in normal rats. The MLE at a 75 mg/kg BW dose and MLEF at a 35 mg/kg BW dose, significantly (p < 0.05) reduced fast blood glucose levels in rats with impaired glucose and lipid metabolism. In total, 34 proteins with significant changes in expression and phosphorylation levels were identified. The changes of JNK, IRS1, and PDK1 were confirmed by western blot analysis. In conclusion, this study demonstrated the potential protective effects of MLE and MLEF against hyperglycemia induced by high-energy diet and toxic chemicals in rats for the first time. The most likely mechanism is the promotion of IRS1 phosphorylation, which leads to insulin sensitivity restoration.     

Reversal of elevated cardiac expression of TGFbeta1 and endothelin-1 in OLETF diabetic rats by long-acting calcium antagonist

The effects of calcium channel blockers (CCBs) on complications associated with diabetes mellitus (DM) have been well studied in clinical and basic science investigations. Cardiovascular complications are a common feature of type 2 DM, and insulin resistance is an early clinical manifestation of type 2 DM. CCBs are widely used to treat cardiovascular diseases in patients with DM. In this study, we used a spontaneous type 2 diabetic rat model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats, at a highly insulin-resistant stage with modest hyperglycemia. We examined cardiac expression of transforming growth factor-beta(1) (TGFbeta(1)) and endothelin-1 (ET-1) in male OLETF rats. At 8 weeks of age, OLETF rats were treated for 12 weeks with the long-acting CCB benidipine (1 mg/kg/day or 3 mg/kg/day, po, n = 12), with hydralazine hydrochloride (3 mg/kg/day, po, n = 12), or with vehicle (OLETF, n = 12), and male age-matched genetic control Long-Evans Tokushima Otsuka (LETO, n = 12) rats were used. Blood pressure was significantly higher in OLETF rats than in LETO rats, and benidipine treatment at both dosages in OLETF rats for 12 weeks did not significantly reduce blood pressure, whereas hydralazine treatment significantly lowered blood pressure in OLETF rats. Hydralazine and both dosages of benidipine significantly reduced upregulated cardiac ET-1 levels in OLETF rats. Plasma and cardiac TGFbeta1 levels were remarkably higher in OLETF rats compared with LETO rats and were normalized by treatment with benidipine (3 mg/kg/day). Our results suggest that CCBs are effective in normalizing upregulated cardiac TGFbeta1 and ET-1 levels at the insulin-resistant stage in OLETF rats, which may improve cardiac morphology and function in this rat model without altering blood pressure and plasma glucose levels. In contrast, hydralazine treatment also normalizes cardiac ET-1 levels while significantly reducing blood pressure.     

Identification of Arsenobetaine,a Water Soluble Organo-arsenic Compound in Muscle and Liver of a Shark,Prionace glaucus

After male rats of the Sprague Dawley strain, 5 weeks old, were fed a 20% casein diet for 12 days, 70 mg of streptozotocin/kg body weight (STZ group) or 70 mg of streptozotocin and 500 mg of nicotinamide/kg body weight (STZ-Nam group) was injected intraperitoneally into the rats. The rats were kept for 21 more days on the 20% casein diet and killed by decapitation. Urine was collected for the last 2 days. The level of blood glucose was 2-fold higher in the STZ group than in the STZ-Nam group. Urinary excretion of large amounts of glucose was observed only in the STZ group. Extremely reduction of urinary excretion of nicotinamide was observed in the STZ group, but, urinary excretion of N¹-methylnicotinamide (MNA) and N-¹-methyl-2-pyridone-5-carboxamide (2-py) was about the same in the two groups and that of N¹-methyl-4-pyridone-3-carboxamide (4-py) was higher in the STZ group than in the STZ-Nam group. The sum of urinary excretion of nicotinamide, MNA, 2-py, and 4-py was higher in the STZ group than in the STZ-Nam group. The levels of NAD in liver, pancreas, and blood in the STZ group tended to be higher, or rather not to decrease compared to the STZ-Nam group. For enzyme activities concerned with the tryptophan-NAD metabolism, a marked increase was observed in the activities of aminocarboxymuconate-semialdehyde decarboxylase, 3-hydroxyanthranilic acid oxygenase, and nicotinamide methyltransferase, on the other hand, the activity of NAD⁺ synthetase decreased in the STZ group compared to the STZ-Nam group. The activities of tryptophan oxygenase, kynureninase, NMN adenylyltransferase, and MNA oxidase were about the same in the two groups. These changes in the above enzyme activities mean that the conversion ratio from tryptophan to NAD is lower in the streptozotocin diabetic rats than normal rats, but the tryptophan metabolites such as NAD and 4-py were higher in the STZ group than in the STZ-Nam group. This might be due to the higher food intake and the lower body weight gain in the STZ group than in the STZ-Nam group. Similar phenomena have reported in alloxan diabetic rats.     

Sirt1与生物钟的相互调控

生物钟调控机制广泛存在于各种类型的细胞中,控制着细胞代谢的节律性变化.最近的研究发现,NAD+依赖的组蛋白去乙酰化酶Sirt1参与了生物钟调控过程,对维持正常的生物钟节律具有重要作用;另一方面,Sirt1的表达也受到生物钟系统的调控,呈现出昼夜节律性的表达.因此Sirt1能与生物钟进行相互调控,并且这一作用机制很可能广泛参与了不同类型细胞内的信号转导和能量代谢过程.本文总结了Sirt1与生物钟之间相互调控的一些研究进展,对它们之间的分子调控机制进行了概述.     

Regulation of radiation-induced liver damage by modulation of SIRT-1 activity: In vivo rat model

Silent information regulator 1 (SIRT-1), a nicotinamide adenine dinucleotide-dependent deacetylase, was found to regulate cell apoptosis, inflammation, and oxidative stress response in living organisms. Therefore, the role of SIRT-1 in regulating forkhead box O/poly ADP-ribose polymerase-1 (FOXO-1/PARP-1) signaling could provide the necessary validation for developing new pharmacological targets for the promotion or inhibition of SIRT-1 activity toward radiation sensitivity. In the present study, the SIRT-1 signaling pathway is being investigated to study the possible modulatory effect of resveratrol (RSV, SIRT-1 activator) versus nicotinamide (NAM, SIRT-1 inhibitor) in case of liver damage induced by whole-body gamma irradiation. Rats were exposed to 6 Gy gamma radiation after being pretreated with either RSV (10 mg/kg/day) or NAM (100 mg/kg/day) for 5 days, and subsequent examining hepatic morphological changes and apoptotic markers were assessed. The expression of SIRT-1, FOXO-1, and cleaved PARP-1 in the liver was analyzed. RSV improved radiation-induced apoptosis, mitochondrial dysfunction, and inflammation signified by low expression of caspase-3, lactate dehydrogenase, complex-I activity, myeloperoxidase, and total nitric oxide content. RSV increased the expression of SIRT-1, whereas cleaved PARP-1 and FOXO-1 were suppressed. These protective effects were suppressed by inhibition of SIRT-1 activity using NAM. These findings suggest that RSV can attenuate radiation-induced hepatic injury by reducing apoptosis and inflammation via SIRT-1 activity modulation.     

Nicotinamide riboside,an NAD+ precursor,attenuates the development of liver fibrosis in a diet-induced mouse model of liver fibrosis

ObjectiveLiver fibrosis is part of the non-alcoholic fatty liver disease (NAFLD) spectrum, which currently has no approved pharmacological treatment. In this study, we investigated whether supplementation of nicotinamide riboside (NR), a nicotinamide adenine dinucleotide (NAD+) precursor, can reduce the development of liver fibrosis in a diet-induced mouse model of liver fibrosis.MethodsMale C57BL/6 J mice were fed a low-fat control (LF), a high-fat/high-sucrose/high-cholesterol control (HF) or a HF diet supplemented with NR at 400 mg/kg/day (HF-NR) for 20 weeks. Features of liver fibrosis were assessed by histological and biochemical analyses. Whole-body energy metabolism was also assessed using indirect calorimetry. Primary mouse and human hepatic stellate cells were used to determine the anti-fibrogenic effects of NR in vitro.ResultsNR supplementation significantly reduced body weight of mice only 7 weeks after mice were on the supplementation, but did not attenuate serum alanine aminotransferase levels, liver steatosis, or liver inflammation. However, NR markedly reduced collagen accumulation in the liver. RNA-Seq analysis suggested that the expression of genes involved in NAD+ metabolism is altered in activated hepatic stellate cells (HSCs) compared to quiescent HSCs. NR inhibited the activation of HSCs in primary mouse and human HSCs. Indirect calorimetry showed that NR increased energy expenditure, likely by upregulation of β-oxidation in skeletal muscle and brown adipose tissue.ConclusionNR attenuated HSC activation, leading to reduced liver fibrosis in a diet-induced mouse model of liver fibrosis. The data suggest that NR may be developed as a potential preventative for human liver fibrosis.     

Comparative and combined effect of chlorogenic acid and tetrahydrocurcumin on antioxidant disparities in chemical induced experimental diabetes

The present study evaluates the combined effect of tetrahydrocurcumin and chlorogenic acid on oxidative stress in streptozotocin–nicotinamide-induced diabetic rats. Rats were rendered diabetic by a single intraperitoneal injection (i.p) of streptozotocin (45 mg/kg BW), 15 min after an i.p injection of nicotinamide (110 mg/kg BW). The levels of fasting plasma glucose and insulin were estimated. As an index of oxidative stress, the levels of enzymic antioxidants and lipid peroxidation products were analyzed in liver and kidney. Diabetic rats showed an increase in the levels of fasting plasma glucose, lipid peroxidative products such as thiobarbituric acid reactive substances and lipid hydroperoxides and a decrease in plasma insulin, and enzymic antioxidants viz., superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase. Combined administration of tetrahydrocurcumin (80 mg/kg BW) and chlorogenic acid (5 mg/kg BW) to diabetic rats for 45 days, reversed the biochemical changes to near normal. The above findings were supported by histological observations of the liver and kidney. Together the present study clearly reflects that combined dosage of tetrahydrocurcumin and chlorogenic acid augments enzymic antioxidants with a concomitant decrease in lipid peroxidation and protects against streptozotocin–nicotinamide-induced type 2 diabetes in experimental rats.     

beta1 antagonist and beta2 agonist, celiprolol, restores the impaired endothelial dependent and independent responses and decreased TNFalpha in rat with type II diabetes

The effect of beta antagonists in the diabetic vascular lesion is controversial. We investigated the effect of celiprolol hydrochloride, a beta1 antagonist and mild beta2 agonist, on the lesions and function in type II male Otsuka Long-Evans Tokushima Fatty (OLETF) diabetic rats. OLETF rats were fed regular chow with or without atenolol (25 mg/kg/day) or celiprolol (100 mg/kg/day) treatment (group DM, no treatment; group DM-a, atenolol treatment; group DM-c, celiprolol treatment), and treatment was continued for 31 days. Separately, normoglycemic control rats, LETO, were prepared as group C. On day 3, endothelial cells of the right internal carotid artery were removed by balloon injury, and the rats were evaluated 4 weeks after balloon injury. The plasma glucose and lipid levels were unchanged throughout the treatment period. Intimal thickening was observed in the right carotid artery in the DM and DM-a groups; however, little thickening was observed in those of DM-c rats. Acetylcholine-induced NO-dependent relaxation in arteries was improved in DM-c rats compared with DM and DM-a rats (maximum relaxation DM 30.8+/-4.5, DM-a 37.4+/-3.9, DM-c 48.8+/-4.6%, *P<0.05 vs. DM for DM-c rats). Tone-related basal NO release and acetylcholine-induced NO-dependent relaxation in the arteries and plasma NO(x) (sum of NO(2)(-) and NO(3)(-)) were greater in DM-c and C groups than in DM and DM-a groups. The serum TNFalpha levels did not increase in DM-c rats compared with those of the DM or DM-a groups, and were comparable with those of group C. CONCLUSION: In conclusion, Celiprolol improves endothelial function in the arteries of OLETF rats, and further restore it 4 weeks after endothelial denudation in the arteries of OLETF rats. NO and O(2)(-) may have a role in the important underlying mechanisms by reducing the TNFalpha levels.     

Age-associated loss of Sirt1-mediated enhancement of glucose-stimulated insulin secretion in beta cell-specific Sirt1-overexpressing (BESTO) mice

The Sir2 (silent i nformation r egulator 2) family of NAD-dependent deacetylases regulates aging and longevity across a wide variety of organisms, including yeast, worms, and flies. In mammals, the Sir2 ortholog Sirt1 promotes fat mobilization, fatty acid oxidation, glucose production, and insulin secretion in response to nutrient availability. We previously reported that an increased dosage of Sirt1 in pancreatic β cells enhances glucose-stimulated insulin secretion (GSIS) and improves glucose tolerance in be ta cell-specific S ir t 1- o verexpressing (BESTO) transgenic mice at 3 and 8 months of age. Here, we report that as this same cohort of BESTO mice reaches 18–24 months of age, the GSIS regulated by Sirt1 through repression of Ucp2 is blunted. Increased body weight and hyperlipidemia alone, which are observed in aged males and also induced by a Western-style high-fat diet, are not enough to abolish the positive effects of Sirt1 on β cell function. Interestingly, plasma levels of nicotinamide mononucleotide (NMN), an important metabolite for the maintenance of normal NAD biosynthesis and GSIS in β cells, are significantly reduced in aged BESTO mice. Furthermore, NMN administration restores enhanced GSIS and improved glucose tolerance in the aged BESTO females, suggesting that Sirt1 activity decreases with advanced age due to a decline in systemic NAD biosynthesis. These findings provide insight into the age-dependent regulation of Sirt1 activity and suggest that enhancement of systemic NAD biosynthesis and Sirt1 activity in tissues such as β cells may be an effective therapeutic intervention for age-associated metabolic disorders such as type 2 diabetes.     

Acarviosine-simmondsin,a novel compound obtained from acarviosine-glucose and simmondsin by Thermus maltogenic amylase and its in vivo effect on food intake and hyperglycemia

Simmondsin was modified with acarviosine-glucose using the transglycosylation activity of Thermus maltogenic amylase to synthesize a novel compound with both antiobesity and hypoglycemic activity. The LC/MS and 13C NMR analyses confirmed that the structure of the major transglycosylation product was acarviosine-simmondsin (Acv-simmondsin), in which acarviosine was attached to the glucose moiety of simmondsin by an alpha-(1,6)-glycosidic linkage. It was found that Acv-simmondsin was a potent competitive inhibitor of alpha-glucosidase with the Ki value of 0.69 microM and a mixed type inhibitor of alpha-amylase with the Ki and KI of 20.78 microM and 26.31 microM, respectively. The administration of Acv-simmondsin (0.1 g/100 g diet/day) to mice for 5 days significantly reduced food intake by 35%, compared to 25% with simmondsin in control obese mice. Acv-simmondsin (50 mg/kg BW) suppressed the postprandial blood glucose response to sucrose (1 g/kg BW) by 74%, compared to 71% with acarbose, in normal rats.     

High fructose-containing drinking water-induced steatohepatitis in rats is prevented by the nicotinamide-mediated modulation of redox homeostasis and NADPH-producing enzymes

An imbalance in the redox state, increased levels of lipid precursors and overactivation of de novo lipogenesis determine the development of fibrosis during nonalcoholic steatohepatitis (NASH). We evaluated the modulation of NADPH-producing enzymes associated with the antifibrotic, antioxidant and antilipemic effects of nicotinamide (NAM) in a model of NASH induced by excess fructose consumption. Male rats were provided drinking water containing 40% fructose for 16 weeks. During the last 12 weeks of fructose administration, water containing NAM was provided to some of the rats for 5 h/day. The biochemical profiles and the ghrelin, leptin, lipoperoxidation and TNF-α levels in serum and the glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and NADP⁺-dependent isocitric dehydrogenase (IDP) levels, the reduced/oxidized glutathione (GSH/GSSG) and reduced/oxidized nicotinamide adenine dinucleotide (phosphate) (NAD(P)H/NAD(P)⁺) ratios, and the levels of various lipogenic and fibrotic markers in the liver were evaluated. The results showed that hepatic fibrosis induced by fructose consumption was associated with weight gain, hunger-satiety system dysregulation, hyperinsulinemia, dyslipidemia, lipoperoxidation and inflammation. Moreover, increased levels of hepatic G6PD and ME activity and expression, the NAD(P)H/NAD(P)⁺ ratios, and GSSG concentration and increased expression of lipogenic and fibrotic markers were detected, and these alterations were attenuated by NAM administration. Specifically, NAM diminished the activity and expression of G6PD and ME, and this effect was associated with a decrease in the NADPH/NADP⁺ ratios, increased GSH levels and decreased lipoperoxidation and inflammation, ameliorating fibrosis and NASH development. NAM reduces liver steatosis and fibrosis by regulating redox homeostasis through a G6PD- and ME-dependent mechanism.

     

Niacin deficiency increases spontaneous and etoposide-induced chromosomal instability in rat bone marrow cells in vivo

Poly(ADP-ribose) polymerase (PARP) binds to DNA single and double strand breaks and uses NAD in the synthesis of poly(ADP-ribose) (pADPr). Niacin deficiency in rats decreases bone marrow NAD(+) and limits pADPr synthesis in response to DNA damage, while pharmacological supplementation with nicotinic acid (NA) increases bone marrow NAD(+) and pADPr. The purpose of this study was to determine if niacin status alters the extent of DNA damage and chromosomal instability before and after treatment with the chemotherapy drug etoposide (ETO). Genotoxicity was evaluated using the comet, micronucleus and sister chromatid exchange (SCE) assays. Male Long-Evans rats were fed niacin deficient (ND), or pair-fed (PF) niacin replete (30mg niacin/kg) or NA supplemented (4g niacin/kg) diets for 3 weeks. Rats were gavaged with ETO (1-25mg/kg) suspended in corn oil or an equal volume of vehicle (CON). Comet analysis demonstrated that ETO-induced DNA damage (mean tail moment (MTM) and proportion of cells with significant damage) was greater in bone marrow cells from ND rats, compared to PF or NA rats. Surprisingly, niacin deficiency alone caused 6.2- and 2.8-fold increases in spontaneous micronucleus formation and SCE frequency, respectively. As expected, ETO treatment increased the level of micronuclei (MN) and SCEs in all diet groups; however, the absolute increases were greater in ND bone marrow. These data show that niacin is required for the maintenance of chromosomal stability and may facilitate DNA repair in vivo, in a tissue that is sensitive to niacin depletion and impaired pADPr metabolism. Pharmacological intakes of niacin do not appear to be further protective compared to adequate intakes. Niacin supplementation may help to protect the bone marrow cells of cancer patients with compromised nutritional status from the side effects of genotoxic chemotherapy drugs.     

NAD precursors as antiteratogens against aminothiadiazole.

The teratogen 2-amino-1,3,4-thiadiazole (ATDA) is an antagonist of nicotinamide, and may act by interfering with the synthesis or utilization of the coenzyme nicotinamide adenine dinucleotide (NAD). Several compounds that can be converted to NAD were tested as antiteratogens against ATDA. At day 11 of gestation (sperm day = day 0) pregnant Wistar-derived rats were given single ip injections of ATDA (100 mg/kg), or ATDA immediately followed by the suspected antiteratogen ip or by gavage, or the antiteratogen alone. Compounds tested were NAD, nicotinamide, nicotinic acid, quinolinic acid, kynurenine sulfate, and L-tryptophan, in doses of 10-200 mg per animal. At autopsy (day 20) fetuses were recovered and examined. It was found that each antiteratogen significantly reduced the frequency of ATDA-induced resorptions and malformations. At certain doses each anteteratogen gave complete protection against ATDA-induced malformations in some, but not all, litters. These results support the hypothesis that ADTA interferes with the synthesis or utilization of NAD and suggest that substances converted to NAD act as antiteratogens against ATDA.     

Regulatory role of Sirt1 on the gene expression of fatty acid‐binding protein 3 in cultured porcine adipocytes

To investigate whether Sirt1 could modulate fatty acid‐binding protein 3 (FABP3), we treated porcine adipocytes either with the Sirt1 inhibitor nicotinamide (NAM), with the Sirt1 activator resveratrol (RES), or by knockdown of Sirt1 by Sirt1‐siRNA. NAM or knockdown with Sirt1‐siRNA significantly inhibited Sirt1 mRNA expression, while increasing FABP3 mRNA levels. RES or RES + Sirt1‐siRNA treatments further proved that Sirt1 negatively regulated FABP3 gene expression in adipocytes. We also found a similar Sirt1 regulation pattern for PPARγ to that of FABP3 in adipocytes. Furthermore, NAM/RES + PPARγ‐siRNA treatments showed that Sirt1 may regulate the FABP3 gene expression partly through the PPARγ‐mediated signals. In summary, Sirt1 regulates the expression of FABP3 gene in adipocytes, and PPARγ apparently plays an important role in this process. J. Cell. Biochem. 107: 984–991, 2009. © 2009 Wiley‐Liss, Inc.