-
1.
Charge Assisted S/Se Chalcogen Bonds in SAM Riboswitches: A Combined PDB and ab Initio Study.
Piña, MLN, Frontera, A, Bauza, A
ACS chemical biology. 2021;(9):1701-1708
Abstract
In this study, we provide experimental (Protein Data Bank (PDB) inspection) and theoretical (RI-MP2/def2-TZVP level of theory) evidence of the involvement of charge assisted chalcogen bonding (ChB) interactions in the recognition and folding mechanisms of S-adenosylmethionine (SAM) riboswitches. Concretely, an initial PDB search revealed several examples where ChBs between S-adenosyl methionine (SAM)/adenosyl selenomethionine (EEM) molecules and uracil (U) bases belonging to RNA take place. While these interactions are usually described as a merely Coulombic attraction between the positively charged S/Se group and RNA, theoretical calculations indicated that the σ holes of S and Se are involved. Moreover, computational models shed light on the strength and directionality properties of the interaction, which was also further characterized from a charge-density perspective using Bader's "Atoms in Molecules" (AIM) theory, Non-Covalent Interaction plot (NCIplot) visual index, and Natural Bonding Orbital (NBO) analyses. As far as our knowledge extends, this is the first time that ChBs in SAM-RNA complexes have been systematically analyzed, and we believe the results might be useful for scientists working in the field of RNA engineering and chemical biology as well as to increase the visibility of the interaction among the biological community.
-
2.
Associations of methyl donor and methylation inhibitor levels during anti-oxidant therapy in heart failure.
Joseph, J, Giczewska, A, Alhanti, B, Cheema, AK, Handy, DE, Mann, DL, Loscalzo, J, Givertz, MM
Journal of physiology and biochemistry. 2021;(2):295-304
-
-
Free full text
-
Abstract
Redox balance and methylation are crucial to homeostasis and are linked by the methionine-homocysteine cycle. We examined whether differences in methylation potential, measured as plasma levels of S-adenosyl methionine (SAM) and S-adenosyl homocysteine (SAH), occur at baseline and during anti-oxidant therapy with the xanthine oxidase inhibitor allopurinol in patients with heart failure with reduced ejection fraction. We analyzed plasma samples collected at baseline and 24 weeks in the Xanthine Oxidase Inhibition for Hyperuricemic Heart Failure Patients (EXACT-HF) study, which randomized patients with heart failure with reduced ejection fraction to allopurinol or placebo. Associations between plasma levels of SAM, SAH, SAM/SAH ratio, and outcomes, including laboratory markers and clinical events, were assessed. Despite randomization, median SAM levels were significantly lower at baseline in the allopurinol group. SAH levels at 24 weeks, and change in SAM from baseline to week 24, were significantly higher in the group of patients randomized to allopurinol compared to the placebo group. A significant correlation was observed between change in SAH levels and change in plasma uric acid (baseline to 24-week changes) in the allopurinol group. There were no significant associations between levels of SAM, SAH, and SAM/SAH ratio and clinical outcomes. Our results demonstrate significant biological variability in SAM and SAH levels at baseline and during treatment with an anti-oxidant and suggest a potential mechanism for the lack of efficacy observed in trials of anti-oxidant therapy. These data also highlight the need to explore personalized therapy for heart failure.
-
3.
S-Adenosylmethionine Increases the Sensitivity of Human Colorectal Cancer Cells to 5-Fluorouracil by Inhibiting P-Glycoprotein Expression and NF-κB Activation.
Mosca, L, Pagano, M, Borzacchiello, L, Mele, L, Russo, A, Russo, G, Cacciapuoti, G, Porcelli, M
International journal of molecular sciences. 2021;(17)
Abstract
Colorectal cancer (CRC) is the second deadliest cancer worldwide despite significant advances in both diagnosis and therapy. The high incidence of CRC and its poor prognosis, partially attributed to multi-drug resistance and antiapoptotic activity of cancer cells, arouse strong interest in the identification and development of new treatments. S-Adenosylmethionine (AdoMet), a natural compound and a nutritional supplement, is well known for its antiproliferative and proapoptotic effects as well as for its potential in overcoming drug resistance in many kinds of human tumors. Here, we report that AdoMet enhanced the antitumor activity of 5-Fluorouracil (5-FU) in HCT 116p53+/+ and in LoVo CRC cells through the inhibition of autophagy, induced by 5-FU as a cell defense mechanism to escape the drug cytotoxicity. Multiple drug resistance is mainly due to the overexpression of drug efflux pumps, such as P-glycoprotein (P-gp). We demonstrate here that AdoMet was able to revert the 5-FU-induced upregulation of P-gp expression and to decrease levels of acetylated NF-κB, the activated form of NF-κB, the major antiapoptotic factor involved in P-gp-related chemoresistance. Overall, our data show that AdoMet, was able to overcome 5-FU chemoresistance in CRC cells by targeting multiple pathways such as autophagy, P-gp expression, and NF-κB signaling activation and provided important implications for the development of new adjuvant therapies to improve CRC treatment and patient outcomes.
-
4.
Sulfur amino acid metabolism and related metabotypes of autism spectrum disorder: A review of biochemical evidence for a hypothesis.
Indika, NR, Deutz, NEP, Engelen, MPKJ, Peiris, H, Wijetunge, S, Perera, R
Biochimie. 2021;:143-157
Abstract
There are multiple lines of evidence for an impaired sulfur amino acid (SAA) metabolism in autism spectrum disorder (ASD). For instance, the concentrations of methionine, cysteine and S-adenosylmethionine (SAM) in body fluids of individuals with ASD is significantly lower while the concentration of S-adenosylhomocysteine (SAH) is significantly higher as compared to healthy individuals. Reduced methionine and SAM may reflect impaired remethylation pathway whereas increased SAH may reflect reduced S-adenosylhomocysteine hydrolase activity in the catabolic direction. Reduced SAM/SAH ratio reflects an impaired methylation capacity. We hypothesize multiple mechanisms to explain how the interplay of oxidative stress, neuroinflammation, mercury exposure, maternal use of valproate, altered gut microbiome and certain genetic variants may lead to these SAA metabotypes. Furthermore, we also propose a number of mechanisms to explain the metabolic consequences of abnormal SAA metabotypes. For instance in the brain, reduced SAM/SAH ratio will result in melatonin deficiency and hypomethylation of a number of biomolecules such as DNA, RNA and histones. In addition to previously proposed mechanisms, we propose that impaired activity of "radical SAM" enzymes will result in reduced endogenous lipoic acid synthesis, reduced molybdenum cofactor synthesis and impaired porphyrin metabolism leading to mitochondrial dysfunction, porphyrinuria and impaired sulfation capacity. Furthermore depletion of SAM may also lead to the disturbed mTOR signaling pathway in a subgroup of ASD. The proposed "SAM-depletion hypothesis" is an inclusive model to explain the relationship between heterogeneous risk factors and metabotypes observed in a subset of children with ASD.
-
5.
S-Adenosylmethionine (SAMe) monotherapy for depression: an 8-week double-blind, randomised, controlled trial.
Sarris, J, Murphy, J, Stough, C, Mischoulon, D, Bousman, C, MacDonald, P, Adams, L, Nazareth, S, Oliver, G, Cribb, L, et al
Psychopharmacology. 2020;(1):209-218
Abstract
RATIONALE Dysregulation of the one carbon cycle is documented in depression. Thereby, S-adenosylmethionine (SAMe), a one-carbon cycle nutraceutical compound with a favourable side effect profile, has a theoretical rationale for efficacy. However, further controlled studies are required to confirm SAMe's efficacy. OBJECTIVES To test the efficacy of SAMe versus placebo in unmedicated DSM-5 diagnosed (major depressive disorder) (MDD) patients with mild-to-moderate levels of depressive symptoms. METHODS We conducted an 8-week, double-blind, randomised controlled trial testing 800 mg/day of SAMe monotherapy versus placebo in 49 patients with MDD (Montgomery-Åsberg Depression Rating Scale [MADRS] score 14-25) who were not currently taking antidepressants. One-carbon cycle biomarkers, brain-derived neurotropic factor (BDNF), and relevant single nucleotide polymorphisms (SNPs) were analysed as potential treatment moderators. RESULTS A clinically relevant differential reduction from baseline to week 8 of 3.76 points occurred on the primary outcome (MADRS) in favour of SAMe. This however was not significant (p = 0.13) on an adjusted linear mixed model, notwithstanding a medium to large effect size of 0.72. A high placebo response rate of 53% occurred (> 50% reduction on MADRS). Exploratory analyses showed that SAMe was however effective in reducing depression amongst participants with milder depression severity (MADRS ≤ 22, p = 0.045). Response was not moderated by BDNF, SNPs, or one-carbon cycle biomarkers, although increased folate concentrations were correlated with improved symptoms in the SAMe group (r = - 0.57, p = 0.026). The treatment was safe and well tolerated. CONCLUSIONS Although a differential reduction in depression symptoms between groups was observed in favour of SAMe, the results of this pilot study were not statistically significant. TRIAL REGISTRATION ANZCTR-Australian New Zealand Clinical Trials Registry; No.: ACTRN12613001299796; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=364900.
-
6.
Recent advances in HemN-like radical S-adenosyl-l-methionine enzyme-catalyzed reactions.
Jin, WB, Wu, S, Xu, YF, Yuan, H, Tang, GL
Natural product reports. 2020;(1):17-28
Abstract
Covering: 2012 to 2019HemN-like radical S-adenosyl-l-methionine (SAM) enzymes have been recently disclosed to catalyze diverse chemically challenging reactions from primary to secondary metabolic pathways. In this highlight, we summarize the reaction examples catalyzed by HemN-like enzymes to date and the enzymatic mechanisms reported. From the recent mechanistic investigations, we reason that there is a shared initiating mechanism wherein a characteristic SAM methylene radical is proposed to abstract a hydrogen atom from an sp3 carbon or add onto an sp2 carbon center although variations occur thereafter from reaction to reaction, as well as providing a brief insight into some future prospects.
-
7.
Adenosylation reactions catalyzed by the radical S-adenosylmethionine superfamily enzymes.
Ding, W, Ji, X, Zhong, Y, Xu, K, Zhang, Q
Current opinion in chemical biology. 2020;:86-95
Abstract
The radical S-adenosylmethionine (SAM) superfamily enzymes reductively cleave SAM to produce a highly reactive 5'-deoxyadenosyl (dAdo) radical, which in most cases abstracts a hydrogen from the substrate and initiates highly diverse reactions. In rare cases, the dAdo radical can add to a sp2 carbon to result in the production an adenosylated product. These radical SAM-dependent adenosylation reactions are present in natural product biosynthetic pathways and can be achieved by using unnatural substrate analogs containing olefin or aryl moieties. This Opinion provides a focused perspective on this emerging type of biochemistry and discusses its potential use in bioengineering and biocatalysis.
-
8.
Dose increase of S-Adenosyl-Methionine and escitalopram in a randomized clinical trial for major depressive disorder.
Sakurai, H, L Carpenter, L, R Tyrka, A, Price, LH, I Papakostas, G, Dording, CM, Yeung, AS, Cusin, C, Ludington, E, Bernard-Negron, R, et al
Journal of affective disorders. 2020;:118-125
-
-
Free full text
-
Abstract
BACKGROUND The optimal dose of S-adenosyl methionine (SAMe) for major depressive disorder (MDD) remains unclear. The objective of this analysis was to address whether a dose increase provided further improvement in cases of insufficient response using data from an existing randomized clinical trial. METHODS Sixty-five patients with MDD who failed to respond to SAMe 1,600 mg/day, escitalopram 10 mg/day, or placebo for 6 weeks were treated with doubled doses of the allocated treatments for the following 6 weeks. Changes in 17-item Hamilton Depression Rating Scale, Inventory of Depressive Symptomatology-Self Rated, and Systematic Assessment for Treatment Emergent Events-Specific Inquiry were compared between the lower and higher dose treatments in each treatment group and among the higher dose treatments of SAMe, escitalopram, and placebo. RESULTS Various depression severity scores decreased significantly for all three treatment arms during the higher dose treatment. No within-group and between-group differences were found in any of the efficacy measures when comparing the doses and treatments. There was a significant difference in reported abdominal discomfort among patients receiving the higher dose of SAMe (31.3%), compared to escitalopram (8.7%) and placebo (3.8%) (χ2=7.32, p = 0.026). LIMITATIONS The sample size was relatively small. The study duration for dose increase was relatively short. CONCLUSIONS Patients with MDD failing to respond to 1,600 mg/day of SAMe may improve after increasing the dose to 3,200 mg/day, but we cannot rule out the contribution of a placebo effect and time-related improvement. The risk of abdominal discomfort may be increased with higher doses of SAMe.
-
9.
S-Adenosylmethionine Inhibits Cell Growth and Migration of Triple Negative Breast Cancer Cells through Upregulating MiRNA-34c and MiRNA-449a.
Coppola, A, Ilisso, CP, Stellavato, A, Schiraldi, C, Caraglia, M, Mosca, L, Cacciapuoti, G, Porcelli, M
International journal of molecular sciences. 2020;(1)
Abstract
Triple-negative breast cancer (TNBC) is one of the most common malignancies worldwide and shows maximum invasiveness and a high risk of metastasis. Recently, many natural compounds have been highlighted as a valuable source of new and less toxic drugs to enhance breast cancer therapy. Among them, S-adenosyl-L-methionine (AdoMet) has emerged as a promising anti-cancer agent. MicroRNA (miRNA or miR)-based gene therapy provides an interesting antitumor approach to integrated cancer therapy. In this study, we evaluated AdoMet-induced modulation of miRNA-34c and miRNA-449a expression in MDA-MB-231 and MDA-MB-468 TNBC cells. We demonstrated that AdoMet upregulates miR-34c and miR-449a expression in both cell lines. We found that the combination of AdoMet with miR-34c or miR-449a mimic strongly potentiated the pro-apoptotic effect of the sulfonium compound by a caspase-dependent mechanism. For the first time, by video time-lapse microscopy, we showed that AdoMet inhibited the in vitro migration of MDA-MB-231 and MDA-MB-468 cells and that the combination with miR-34c or miR-449a mimic strengthened the effect of the sulfonium compound through the modulation of β-catenin and Small Mother Against Decapentaplegic (SMAD) signaling pathways. Our results furnished the first evidence that AdoMet exerts its antitumor effects in TNBC cells through upregulating the expression of miR-34c and miR-449a.
-
10.
Lysosomes Alteration in HeLa Cell Exposed with 1-Aminocyclopropane-1-Carboxylic Acid, the Ethylene Precursor of Plant Hormones.
Heo, MY, Park, RM, Kim, BN, Nguyen, NT, Jang, HW, Kim, YH, Min, J
Molecular biotechnology. 2020;(11-12):557-562
Abstract
The study of senescence preservative on cut flowers helps boost the commercial value of flowers. Senescence in cut flower is associated with an increase of ethylene production, and is significantly influenced by ethylene pathway. This study was conducted to investigate whether S-adenosyl-L-methionine (SAM) and aminocyclopropane-1-carboxylic acid (ACC) involved in the ethylene synthesis process are correlated with the lysosome. The alterations of lysosome which was treated with the ethylene precursors ACC and SAM in HeLa cell using the confocal laser scanning microscope were investigated. According to the experimental results, the activity of lysosomes increased concentration dependently by ACC treatment, however, no change was observed by SAM treatment. In addition, Liquid chromatography-mass spectrometry (LC/MS) analysis was performed to confirm the effect of lysosomal enzyme (LE) extracted from egg white on ACC reduction, but no change was observed. On the contrary, to confirm the effect of ACC on lysosomes, lysosomes were extracted from HeLa cells treated with 5 mM ACC and confirmed by FE-SEM. The results showed that the size of lysosomes treated with ACC is larger than that of the control, which was treated with distilled water. The lysosomes in the control group were distributed in various ranges from 0 to 800 nm, but those treated with 5 mM ACC were in the range of 400 nm to 800 nm or more. Therefore, lysosomes had no effect on ACC, the precursor of ethylene, the aging hormone of cut flowers, however, ACC had effect on lysosomes.