S-adenosylmethionine Group Research Articles

S-adenosylmethionine attenuates angiotensin II-induced aortic dissection formation by inhibiting vascular smooth muscle cell phenotypic switch and autophagy

It is well known that aortic dissection (AD) is a very aggressive class of vascular diseases. S-adenosylmethionine (SAM) is an autophagy inhibitor with anti-inflammatory and anti-oxidative stress effects; however, the role of SAM in AD is unknown. In this study, we constructed an animal model of AD using subcutaneous minipump continuous infusion of AngII-induced ApoE-/-mice and a cytopathic model using AngII-induced primary vascular smooth muscle cells (VSMCs) to investigate the possible role of SAM in AD. The results showed that mice in the AngII + SAM group had significantly lower AD incidence, significantly prolonged survival, and reduced vascular elastic fiber disruption compared with mice in the AngII group. In addition, SAM significantly inhibited autophagy in vivo and in vitro. Meanwhile, SAM also inhibited the cellular phenotypic switch, mainly by up regulating the expression levels of contractile marker proteins [α-smooth muscle actin (α-SMA) and smooth muscle 22α (SM22α)] and down regulating the expression levels of synthetic marker proteins [osteoblast protein (OPN), matrix metalloproteinase-2 (MMP2), and matrix metalloproteinase-9 (MMP9)]. Molecularly, SAM inhibited AD formation mainly by activating the PI3K/AKT/mTOR signaling pathway. Using a PI3K inhibitor (LY294002) significantly reversed the protective effect of SAM in AngII-induced mice and VSMCs.Our study demonstrates the protective effect of SAM on mice under AngII-induced AD for the first time. SAM prevented AD formation mainly by inhibiting cellular phenotypic switch and autophagy, and activation of the PI3K/AKT/mTOR signaling pathway is a possible molecular mechanism. Thus, SAM may be a novel strategy for the treatment of AD.

SAM protects against alveolar septal cell apoptosis in autoimmune emphysema rats

BackgroundHypomethylation of the perforin gene promoter in CD4 + T cells, inflammation and oxidative stress, might be involved in alveolar septal cell apoptosis associated with emphysema in rats. This study aimed to investigate the effects of S-adenosylmethionine (SAM) on this kind of apoptosis in rats with autoimmune emphysema.MethodsTwenty-four rats were randomly divided into three groups: a normal control group, a model group, and a SAM group. Pathological changes in lung tissues were observed, and the mean linear intercept (MLI) and mean alveolar number (MAN) were measured. The levels of anti-endothelial cell antibodies (AECA) in serum, alveolar septal cell apoptosis, perforin gene promotor methylation in CD4 + T cells in the spleen, and the levels of cytokines, malondialdehyde (MDA), and glutathione (GSH) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in bronchoalveolar lavage fluid (BALF) were investigated.ResultsThe MLI, apoptosis index (AI) of alveolar septal cells, levels of AECA in serum, and levels of tumour necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9) and MDA in BALF were increased, while the MAN, methylation levels, and the activities of GSH, SOD and GSH-Px in BALF were decreased in the model group compared with those in the normal control group and the SAM group (all P < 0.05). The levels of interleukin-8 (IL-8) in BALF were greater in the model group than in the normal control group (P < 0.05).ConclusionsSAM protects against alveolar septal cell apoptosis, airway inflammation and oxidative stress in rats with autoimmune emphysema possibly by partly reversing the hypomethylation of the perforin gene promoter in CD4 + T cells.

Role of DNA methylation in sepsis-associated encephalopathy in mice

Objective To evaluate the role of DNA methylation in sepsis-associated encephalopathy in mice. Methods A total of 144 clean-grade healthy male C57BL/6 mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups (n=36 each) using a random number table method: sham operation group (group Sham), sepsis group (group Sepsis), sham operation plus S-adenosyl methionine (SAM) group (group Sham+ SAM) and sepsis plus SAM group (group Sepsis+ SAM). Sepsis was produced by cecum ligation and puncture (CLP). In Sham+ SAM and Sepsis+ SAM groups, DNA methylated methyl donor SAM 100 mg/kg was intraperitoneally injected at 1 h before operation and 12 h after operation, while the equal volume of normal saline was given instead in Sham and Sepsis groups.The cognitive function was assessed using Y-maze and contextual fear conditioning test at 1, 3 and 7 days after CLP.Mice were sacrificed at 1, 3 and 7 days after CLP, and the hippocampal tissues were taken for determination of genome-wide DNA methylation (by colorimetric assay) and expression of DNA methyltransferase enzymes (DNMT1, DNMT3a, and DNMT3b), ten-eleven translocation (TET) enzymes (TET1, TET2 and TET3) and thymine-DNA glycosylase (TDG) mRNA (by fluorescent quantitative real-time). Results Compared with group Sham, the time of staying at the novel arm was significantly shortened, the percentage of time spent freezing and the total number of entries into each arm were reduced, genome-wide DNA methylation in hippocampal tissues was decreased at 1, 3 and 7 days after CLP, the expression of DNMT1, DNMT3a, TET1, TET2, TET3 and TDG was up-regulated, and the expression of DNMT3b was down-regulated in group Sepsis (P<0.05). Compared with group Sepsis, the time of staying at the novel arm was significantly prolonged, the percentage of time spent freezing and the total number of entries into each arm were increased, the expression of DNMT1, DNMT3a, TET1, TET2, TET3 and TDG mRNA was down-regulated, and the expression of DNMT3b was up-regulated in group Sepsis+ SAM(P<0.05). Conclusion DNA methylation is involved in the development of sepsis-associated encephalopathy in mice. Key words: DNA methylation; Sepsis-associated encephalopathy

S-Adenosylmethionine attenuates bile duct early warm ischemia reperfusion injury after rat liver transplantation

Warm ischemia reperfusion injury (IRI) plays a key role in biliary complication, which is a substantial vulnerability of liver transplantation. The early pathophysiological changes of IRI are characterized by an excessive inflammatory response. S-Adenosylmethionine (SAM) is an important metabolic intermediate that modulates inflammatory reactions; however, its role in bile duct warm IRI is not known. In this study, male rats were treated with or without SAM (170 μmol/kg body weight) after orthotopic autologous liver transplantation. The histopathological observations showed that bile duct injury in the IRI group was more serious than in the SAM group. The alanine aminotransferase (ALT), alkaline phosphatase (ALP) and direct bilirubin (DBIL) levels in the serum of the IRI group were significantly increased compared to the SAM group (P < .05). Simultaneously, SAM effectively improved the survival of the transplant recipients. Furthermore, the H2O2 and malondialdehyde (MDA) of the IRI group were much higher compared to the SAM group (P < .05). The GSH/GSSG ratio in the SAM group was significantly increased by SAM treatment compared to the IRI group (P < .05). SAM administration significantly inhibited macrophage infiltration in liver and bile duct tissues, down-regulated TNF-α levels and up-regulated IL-10 expression in bile duct tissues compared to the IRI group (P < .05). The number of apoptotic biliary epithelial cells and caspase-3-positive cells in IRI rat livers were much higher compared to those in SAM-treated rats at 24 h after liver transplantation (P < .05). These data suggested that SAM protected bile ducts against warm IRI by suppressing oxidative stress, inflammatory reactions and apoptosis of biliary epithelial cells after liver transplantation.α

P.3.008 S-Adenosyl-methionine impairs forced swimming-induced behavioural immobility by inhibiting gene expression in dentate gyrus neurons

The consolidation of stress-induced adaptive behaviours, such as the learned immobility response in the forced swim (FS) test, depends on specific epigenetic modifications underlying gene transcriptional responses in dentate gyrus (DG) granule neurons of the hippocampus. In these neurons FS evokes the activation of two interacting signalling pathways, i.e. the glucocorticoid receptor (GR) and the NMDAR/ERK1/2/MSK1-Elk-1 pathways, resulting in phosphorylation of serine10 and acetylation of lysine14 at histone H3 (H3S10p-K14ac) which leads to induction of immediate early genes (IEGs) c-Fos and Egr-1 [1,2]. These molecular responses are critical for the consolidation of the behavioural immobility response [1,2]. The drug and endogenous methyl-donor S-adenosylmethionine (SAM) impairs the consolidation of the behavioural immobility response [3] suggesting the involvement of histone methylation and/or DNA methylation in gene transcriptional control underlying the behavioural response but this is unknown. Therefore, to understand the mechanism of action of SAM and to gain insight into the involvement of histone/DNA methylation, rats were injected with SAM (100 mg/kg s.c.) 30 minutes before FS (15 min, 25oC). Twenty-four hours later they were subjected to FS again and immobility behaviour were scored in 10 s bins. SAM had no effect on immobility in the initial FS test (mean±SEM; vehicle: 15.8±1.6 bins, n = 8; SAM: 15.0±1.9 bins, n = 9; P>0.05 post-hoc Bonferroni test). However, in the retest, immobility in the SAM group was significantly lower (11.4±3.3 bins, n = 9) than that in the vehicle group (20.6±2.3 bins, n = 8; P<0.05), confirming that SAM indeed impairs the consolidation of the behavioural immobility response [3]. To study whether SAM's effects on behaviour could be explained through effects on FS-induced epigenetic and transcriptional responses in DG neurons, rats were pre-treated with SAM or vehicle and submitted to FS or not (baseline control) and killed 1 h later. Compared to vehicle, SAM evoked a significant decrease in FSinduced c-Fos and Egr-1in DG neurons (Vehicle: c-Fos: 127.1±4.6 neurons n = 5, Egr-1: 18.4±2.5 n = 5; SAM: c-Fos 82.6±5.0 neurons n = 6, Egr-1 8.5±1.2 n = 5; both c-Fos and Egr-1: P<0.01). However, SAM had no effect on stress-induced H3S10p-K14ac in DG neurons suggesting that the drug effect was independent of this dual epigenetic mark. Next, we investigated the effect of SAM and FS on the methylation status of histone H3 lysine residues. Chromatin immuno-precipitation (ChIP) analysis revealed that SAM and FS had no significant effects on H3K4me3, H3K9me3 and H3K27me3 at the c-Fos and Egr-1 promoters. Recently, we have started investigating DNA methylation using bisulfite pyrosequencing and methyl-DNA IP (MeDIP) to assess the cytosine methylation status of CpG islands within the c-fos and egr-1 gene promoters. We found that cytosine methylation of both promoters was very low (<5%) in the DG, the rest of hippocampus, and the neocortex and did not change after FS. Presently we are S64 Epigenetics: towards new drug targets studying the effects of SAM on de novo DNA methylation of the gene promoters. We conclude that SAM impairs the FS-induced behavioural immobility response through inhibition of gene transcription in DG neurons. This drug effect appears to be independent of histone modifications.

S24 * S-ADENOSYLMETHIONINE IN THE PATHOGENESIS AND TREATMENT OF ALCOHOLIC LIVER DISEASE * S24.1 * THE ROLE OF ALTERED SAME METABOLISM IN ALCOHOL-INDUCED ER STRESS AND LIVER INJURY

S24 * S-ADENOSYLMETHIONINE IN THE PATHOGENESIS AND TREATMENT OF ALCOHOLIC LIVER DISEASE * S24.1 * THE ROLE OF ALTERED SAME METABOLISM IN ALCOHOL-INDUCED ER STRESS AND LIVER INJURY

Effects of S-adenosylmethionine on liver methionine metabolism and steatosis with ethanol-induced liver injury in rats

BackgroundHyperhomocysteinemia is implicated in the pathogenesis of various liver diseases. In this study, the effects of S-adenosylmethionine (SAM) on hyperhomocysteinemia and steatosis with ethanol-induced liver injury in rats were examined and their mechanisms were explored.MethodsForty-eight female Sprague–Dawley rats were randomly divided into four groups as control, model, low-dose, and high-dose SAM groups. Except the control group, all rats were fed high-fat-containing diet plus ethanol and fish oil gavaged for 8 weeks. SAM was administered by intraperitoneal injection after the 4 weeks’ exposure of ethanol. Serum homocysteine (Hcy), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), tumor necrosis factor α (TNF-α), and transforming growth factor β1 (TGF-β1) levels were determined. The contents of liver malondialdehyde (MDA) and glutathione (GSH) were assayed. Liver histology was also examined. The expressions of TNF-α and TGF-β1 mRNAs in the liver were detected by the reverse transcriptase-polymerase chain reaction assay.ResultsCompared with the control group, the model group rats developed marked liver damage, accompanied by an increase in Hcy, ALT, AST, TC, TG, TNF-α, TGF-β1, and MDA levels. However, the levels of GSH were decreased. These responses were associated with the increased expression of TNF-α and TGF-β1 mRNAs in the livers, as well as the existence of hepatocellular necrosis and neutrophil infiltration in the livers. In treatment groups, SAM provided significant protection from the liver injury induced by alcohol, resulting in a decrease in serum TNF-α, TGF-β1 levels, lipid peroxidation, and the expressions of TNF-α and TGF-β1 mRNAs in the livers, as well as an increase in GSH levels. However, no statistical difference was observed in these parameters between the two different dose treatment groups. In the study, SAM did not affect plasma total homocysteine (tHcy) levels significantly. ConclusionSAM prevents alcohol-induced liver injury in rats by reducing liver lipid peroxidation, anti-inflammation, and antihyperplasia. In addition, it does not affect the plasma tHcy levels.

In vitro effect of s-adenosyl methionine on ethanol embryopathy in the rat

S-adenosyl methionine (SAM) is a universal methyl donor for biological systems. Chronic consumption of ethanol results in depletion of available SAM and reduces its biosynthesis in the transmethylation pathway. Administration of excess SAM may reduce the embryopathic effects of ethanol. The in-vitro effects of SAM on ethanol embryopathy was investigated by culturing 9.5 day old whole rat embryos for 48 hours in ethanol alone (Group II), 0.05 mM SAM (Group III), ethanol + 0.05 mM SAM (Group IV), ethanol + 0.1 mM SAM (Group V), ethanol + 1 mM SAM (Group VI), and in ethanol + 3 mM SAM (Group VII). In Group VII embryos, cardiovascular, nervous, auditory, visual, craniofacial and musculoskeletal systems were retarded in development; crown-rump length, yolk-sac diameter, as well as morphological scores, were reduced compared to those in embryos treated with ethanol alone (Group II). There were, however, significant differences between Group II and Group IV embryos with respect to crown-rump length, yolk sac diameter and somite number. The mean crown-rump length, yolk sac diameter and somite number in Group II were 2.3 +/- 0.2, 2.8 +/- 0.3 and 22.4 +/- 3.5 respectively, compared to 2.6 +/- 0.2, 3.1 +/- 0.2 and 25.3 +/- 3.1 in Group IV. These results suggest that simultaneous administration of S-adenosyl methionine and ethanol may protect against the embryopathic effects of ethanol.

Oral S-adenosylmethionine in the symptomatic treatment of intrahepatic cholestasis: A double-blind, placebo-controlled study

Parenterai S-adenosylmethionine proved to be effective in reversing intrahepatic cholestasis in pregnant women. Based on these findings, a prospective multicenter, double-blind, placebo-controlled trial was planned to assess whether oral S-adenosylmethionine is effective in cholestatic patients with chronic liver disease. Accordingly, 220 inpatients (26% chronic active hepatitis, 68% cirrhosis, 6% primary biliary cirrhosis) with stable (1 month or more) at least twofold increases in serum total and conjugated bilirubin and alkaline phosphatase volunteered for the trial. Serum markers of cholestasis significantly (P < 0.01) decreased after oral S-adenosylmethionine administration (1600 mg/day), and their values were significantly (P < 0.01) lower than the corresponding values in the placebo group. S-adenosylmethionine significantly (P < 0.01) improved subjective symptoms such as pruritus, fatigue, and feeling of being unwell, whereas placebo was ineffective. Two patients in the S-adenosylmethionine group and 9 controls (P < 0.05) withdrew from the trial for reduced compliance because of inefficacy of treatment. Oral S-adenosylmethionine was tolerated to the same extent as placebo. In conclusion, short-term administration of oral S-adenosylmethionine is more effective than placebo in improving clinical and laboratory measures of intrahepatic cholestasis and offers a new therapeutic modality for the symptomatic management of this syndrome.