Methionine Deficiency Research Articles

Effect of Dietary Methionine Deficiency Followed by a Re-Feeding Phase on the Hepatic Antioxidant Activities of Lambs.

Simple SummaryDietary methionine is closely related to oxidative stress metabolism. Lambs were treated with methionine restriction and subsequent methionine re-feeding. The relationship among dietary methionine pattern, methionine metabolism, and antioxidant reactions was studied by detecting methionine metabolite content and antioxidant expression in order to provide theoretical basis for amino acid nutrition and healthy feeding of lambs.Our objective was to investigate the effect of methionine restriction and resuming supply on liver antioxidant response in lambs. The concentrations of methionine and its metabolites and the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2), a redox sensitive factor, were detected after methionine restriction treatment for 50 days and methionine supply recovery for 29 days. The expression of glutathione (GSH) S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were characterized at the level of transcription and translation. Methionine restriction can directly change the content of methionine and its metabolites in plasma and liver, and affect the redox state of lambs by activating the Nrf2 signaling pathway. Liver tissue can adapt to oxidative environment by upregulating the expression of antioxidant enzymes such as GSH-Px and SOD. Moreover, it was found that there was a lag effect in the recovery of metabolism after methionine supplementation.

A common risk variant in the MTHFR gene contributes to age‐related cerebrovascular dysfunction in VCID

AbstractBackgroundCerebrovascular damage occurs during aging, Alzheimer’s disease and Vascular Dementia, commonly referred to as Vascular Contributions to Cognitive Impairment and Dementia (VCID). However, few mouse models currently recapitulate human cerebrovascular deficiencies in disease. The C677T variant in methylenetetrahydrofolate reductase (MTHFRC677T ) is commonly associated with VCID. MTHFR codes for an enzyme involved in production of folate, homocysteine, and methionine metabolism. The MTHFRC677T polymorphism is predicted to result in hyperhomocysteinemia, a condition that causes vascular inflammation and vascular damage. Additionally, methionine deficiency can result in DNA hypomethylation and has been confirmed in MTHFRC677T carriers. Despite the fact that, in some populations, MTHFRC677T is more common than APOE E4, mechanisms by which MTHFR C677T increases risk for VCID are not known.MethodsCRISPR technology was employed to engineer the Mthfr C677T allele into C57BL/6J (B6) mice. Vascular health is being assessed in 6, 12, 18 and 24 months‐old mice using leakage assays (FITC‐dextran and presence of extravascular fibrin) and immunofluorescence (IF) to examine blood brain barrier integrity in the cerebrovascular unit: endothelium (CD31) smooth muscle (aSMA) pericytes (PDGRFb) basement membrane (ColIV) and tight junctions (Claudin‐5, Occludin, ZO‐1). Functional MRI is used to determine in vivo vascular reactivity. Bulk RNA sequencing and Reduced Representation Bisulfite Sequencing (RRBS) were performed on half brains to assess differential gene expression and DNA methylation, respectively.ResultsMice with the Mthfr C677T risk variant have significantly reduced liver enzymatic activity, significantly increased plasma homocysteine levels and decreased methionine levels, recapitulating the human phenotype. Transcriptional profiling of brain tissue revealed genes regulating circadian rhythm, neurogenesis, ER stress and GABA signaling are differentially expressed (DE) in B6.Mthfr C677T compared to B6 samples. RRBS data demonstrated significant genome‐wide DNA hypomethylation in these mice. Hypomethylated and DE genes are expressed in astrocytes, microglia and endothelial cells and are predicted to regulate apoptosis/proliferation, inflammation and glucose transport across the blood brain barrier. Validation by IF is underway.ConclusionWe have created a novel mouse strain to determine the precise mechanisms by which MTHFR C677T increases risk for VCID. This work aims to identify novel therapeutic approaches that preserve cerebrovascular health throughout aging to prevent VCID.

Critical importance of dietary methionine and choline in the maintenance of lung homeostasis during normal and cigarette smoke exposure conditions.

Genetic predispositions and environmental exposures are regarded as the main predictors of respiratory disease development. Although the impact of dietary essential nutrient deficiencies on cardiovascular disease, obesity, and type II diabetes has been widely studied, it remains poorly explored in chronic respiratory diseases. Dietary choline and methionine deficiencies are common in the population, and their impact on pulmonary homeostasis is currently unknown. Mice were fed choline- and/or methionine-deficient diets while being exposed to room-air or cigarette smoke for up to 4 wk. Lung functions were assessed using the FlexiVent. Pulmonary transcriptional activity was assessed using gene expression microarrays and quantitative PCR. Immune cells, cytokines, and phosphatidylcholine were quantified in the bronchoalveolar lavage. In this study, we found that short-term dietary choline and/or methionine deficiencies significantly affect lung function in mice in a reversible manner. It also reduced transcriptional levels of collagens and elastin as well as pulmonary surfactant phosphatidylcholine levels. We also found that dietary choline and/or methionine deficiencies markedly interfered with the pulmonary response to cigarette smoke exposure, modulating lung function and dampening inflammation. These findings clearly show that dietary choline and/or methionine deficiencies can have dramatic pathophysiological effects on the lungs and can also affect the pathobiology of cigarette smoke-induced pulmonary alterations. Expanding our knowledge in the field of "nutri-respiratory research" may reveal a crucial role for essential nutrients in pulmonary health and disease, which may prove to be as relevant as genetic predispositions and environmental exposures.

1833-P: A Novel Genetic Modified and Pegylated FGF21 Analog for the Treatment of Nonalcoholic Steatohepatitis in Nonhuman Primates

Nonalcoholic steatohepatitis (NASH) is becoming a major cause of liver diseases with no effective drugs in the clinic. Fibroblast growth factor 21 (FGF-21) has emerged as a potent metabolic regulator with therapeutic prospect to lipids and NASH in animal models and preclinical trials. FGF-21 and the agents mimicking its activity may be developed into the pharmacotherapeutic targets for NASH treatment. Here, we show that B1344, a site-specific PEGylated human FGF-21 analog, shifts physiology of NASH mice or cynomolgus monkeys towards that of the control animals fed with standard diet, and significantly improves their NASH phenotypes. To determine the role of B1344 in the progression of murine NAFLD independent of obesity, methionine and choline deficiency (MCD) diet-fed mouse model of NASH were generated. Both short- and long-term administration of B1344 with the doses of 0.125 mg/kg and 0.2 mg/kg in mice protect against lipotoxicity damage and liver fibrosis. Expression levels of proinflammatory and fibrotic genes are decreased in livers of mice treated with B1344. Moreover, pharmacologic efficacies of B1344 on NASH were evaluated in NAFLD cynomolgus monkeys fed with high-fat diet. Strikingly, administration of B1344 causes a potent reduction of hepatic steatosis and fibrosis as measured by magnetic resonance imaging proton density fat fraction (MRI-PDFF) and Sirius Red staining, and protects the monkeys from the progression of steatohepatitis. In addition, administration of B1344 results in a reduction of body weight and adiposity, and improvement of lipid profile and glycemic control. The biological properties of the novel FGF-21 analog B1344 is identical to human FGF-21. Together, these demonstrate impressive effects of B1344 on NASH and metabolic parameters, and may represent novel therapeutics for treating these diseases in humans. Disclosure A. Cui: None. J. Li: None. S. Ji: None. F. Ma: None. G. Wang: None. Y. Xue: None. Z. Liu: None. X. Ma: None. Y. Li: None. Funding Tasly Pharmaceutical Co. Ltd.; National Key Research and Development Program of China (2019YFA0802502); National Natural Science Foundation of China (81925008); Chinese Academy of Sciences (XDA12030210); Shanghai Science and Technology Commission (19140903300); National Science and Technology Major Projects (2019ZX09201001-001-001)

Lean Non-Alcoholic Fatty Liver Disease (NAFLD)

Non-Alcoholic Fatty Liver Disease (NAFLD) is a condition that can develop into advanced liver disease. The NAFLD spectrum includes simple steatosis, non-alcoholic steatohepatitis (NASH), liver fibrosis, and liver cirrhosis to hepatocellular carcinoma. One of the underlying pathophysiologies is insulin resistance found in metabolic syndrome. People with metabolic syndrome are not always obese, and NAFLD can also be found in this group, known as lean NAFLD, which has different metabolic characteristics. Metabolic characteristics of lean NAFLD include high levels of transaminases and insulin, low insulin sensitivity, low fasting glucose, low necroinflammatory activity, and liver fibrosis. Some related factors are methionine and choline deficiency, excessive acyl-coA expression, and PNPLA3 gene polymorphism. Lean NAFLD is an interesting topic to discuss because practitioners' awareness of lean NAFLD is lower compared to obese patients. NAFLD is a risk factor for chronic diseases such as cardiovascular disease, kidney disease, colorectal, atrial fibrillation, and hypothyroidism, so it is essential to be recognized by clinicians. To date, there are no guidelines or recommendations that discuss specific treatments in this lean NAFLD population. Â

Association of MTHFR 677C > T genetic polymorphism with extrapyramidal side effects of antipsychotic treatment

Several studies have revealed a positive association between methylenetetrahydrofolate reductase (MTHFR) single nucleotide polymorphism 677C > T and schizophrenia. In T-allele carriers the functional activity of MTHFR is reduced contributing to hyperhomocysteinemia development, methionine deficiency and as a consequence - redox dysregulation and the alteration of dopamine synthesis. The aim of this study was to investigate the association of MTHFR677C > T with the severity of extrapyramidal side effects of antipsychotics in schizophrenia. The average score on the Simpson-Angus scale (SAS) in a group of patients with MTHFR 677 T-allele (n = 30; 13.27 ± 5.10, M ± SD) was statistically significantly higher (t = −2.40; p = 0.02) than in the comparison group of wild genotype MTHFR 677 CC carriers (n = 31; 9.84 ± 6.03, M ± SD), confirming the working hypothesis about a possible association of the MTHFR677 T-allele carriage with the development of extrapyramidal side effects of antipsychotics.

Role of CD44 in Non-Alcoholic Steatohepatitis (NASH) Progressivity

Non alcoholic Steatohepatitis (NASH) is part of a group of conditions called Non-Alcoholic Fatty Liver Diseases(NAFLD) where it is a chronic disease, which defined after elimination other causes of fatty liver, such as excessivealcohol consumption and other causes of chronic liver diseases. NASH is fatty liver disease which characterized byballooning of hepatocyte and lobular inflammation with or without fibrosis. Histopathology diagnose on NASH can bedefined by performing liver biopsy. The purpose of liver biopsy is to define level and degree of the disease. Cluster ofDifferentiation (CD) 44 is a transmembrane glycoprotein receptor which located on the surface of macrophage cells,lymphocytes and endothelial cells. In studies which conducted on mice and humans, showed that CD44 playsimportant role in the progression of NASH. CD44 regulates inflammation of adipose tissue and liver. CD44 ispresumed as a marker which increase macrophage infiltration and other inflammatory cells on liver. This processleads to ultimate increment on insulin resistance and fatty liver. Deficiency was discovered on mice which injectedwith methionine and choline deficiency diet (MCDD). CD44 is associated with preventive method to prevent livercomplication by reducing macrophage or monocyte and as well as neutrophil accumulation in liver which wasevaluated through reducing numbers of inflammatory focus, expression of inflammatory cytokines: tumor necrosisfactor α (TNFα), interleukin (IL) -1B and nitric oxide synthesis (iNOS), and pro-inflammatory types of macrophage. Inobese patients, number of CD44 is predicted to be increasing.

Antagonizing circRNA_002581\u2013miR-122\u2013CPEB1 axis alleviates NASH through restoring PTEN\u2013AMPK\u2013mTOR pathway regulated autophagy

Circular RNAs (circRNAs) have been shown to play critical roles in cancer biology, but their functions in nonalcoholic steatohepatitis (NASH) remain unexplored. Full length of circRNA_002581 was amplified and sequenced, followed by RNA immunoprecipitation, RNA-Fluorescence in Situ Hybridization and dual luciferase reporter gene analysis to confirm the existence of the circRNA_002581–miR-122–CPEB1 regulatory axis in vitro. CircRNA_002581 knockdown was used to study its roles in high concentration of free fatty acids-induced NASH-like cell model and a methionine and choline deficiency (MCD) diet-induced NASH mice model. Autophagy flux and related potential PTEN–AMPK–mTOR pathway were tested by western blot. CircRNA_002581 overexpression significantly relieved the inhibitory role of miR-122 on its target CPEB1 by sponging miR-122. CircRNA_002581 knockdown markedly attenuated lipid droplet accumulation, reduced the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), pro-inflammatory cytokines, apoptosis, H2O2, and increased ATP level in both mice and cellular models of NASH. Mechanistically, circRNA_002581 interference significantly rescue the defective autophagy evidenced by increased autophagosome number, upregulated LC3-II/I level, and decreased p62 level. Further chloroquine-mediated total autophagy inhibition antagonizes the protective effect of circRNA_002581 knockdown. Finally, CPEB1–PTEN–AMPK–mTOR pathway is shown to link the autophagy and circRNA_002581 knockdown-mediated NASH alleviation. CircRNA_002581–miR-122–CPEB1 axis actively participates in the pathogenesis of NASH through PTEN–AMPK–mTOR pathway-related autophagy suppression. Targeting circRNA_002581 is a potential therapeutic strategy for NASH through partial autophagy restoration.

Dietary methionine level alters growth, digestibility, and gene expression of amino acid transporters in meat-type chickens

Imbalance in nutrients can affect digestibility of amino acids by altering gene expression of amino acid transporters. We investigated digestibility and molecular transporters of essential amino acids in chickens fed a methionine-deficient diet. A total of 40 chicks (23 D old) were randomly assigned to either a control (0.49% methionine) or a deficient (0.28%) diet until 41 D when they were sampled for Pectoralis (P.) major, kidney, ileum, and hypothalamus for mRNA expression analysis. The ileal content was collected for apparent ileal digestibility (AID) analysis. Birds fed the deficient diet had reduced growth and worse feed efficiency compared to control. The AID of methionine was similar between both groups. The AID of other essential amino acids was higher in the deficient group than control. mRNA expression of b0,+ AT and LAT4 were upregulated in the ileum and kidney but LAT1 was downregulated only in kidney of the deficient group compared to control. In the P. major, SNAT1, SNAT2, and CAT1 were upregulated in the deficient group compared to control. A diet deficiency in methionine affects digestibility of essential amino acids and cysteine, but not the digestibility of methionine. The change in digestibility is reflected in the mRNA expression of amino acid transporters across different tissues.

Dietary methionine deficiency reduces laying performances of female common ducks and impacts traits of interest of their mule ducklings

The effects of maternal nutrition on offspring phenotypes have been mainly documented over the past years in mammals, and are now studied in poultry as well. In the present study, we investigated the effects of a reduced level of dietary Methionine (Met) on laying performances of common laying ducks and their impacts on the phenotype of their mule ducklings. A total of 60 female laying ducks were divided into 2 dietary treatments at 10 wk of age. The restricted group received Met-restricted diets (R group) containing 0.25% of Met whereas the control group received control diets (C group) containing 0.40% of Met that meets Met requirements. The restriction was applied during the growing and laying periods, from 10 to 51 wk of age and a particular focus was put on female breeder traits that might be affected by the Met restriction. Plasma parameters of hepatic and lipid metabolisms were recorded in ducklings. Total weight (P<0.001), albumen weight (P<0.001) and albumen percentage of dry matter (P<0.01) were decreased for eggs laid by female breeders from the R group. Both male and female ducklings from the R group of female breeders showed a reduced BW at hatching (P<0.001) and a tendency to an increased proportional liver weight (P=0.07). Finally, the maternal low dietary Met level modified plasma parameters in newborn ducklings regardless of sex: alkaline phosphatase (ALP) and alanine transaminase (ALT) activities were reduced (P=0.07 and P=0.002, respectively), levels of glucose (P=0.03) and triglycerides (P=0.01) were higher whereas level of free fatty acids decreased (P=0.01). It was concluded that feeding female laying ducks with a restricted dietary Met content during the growing and laying periods has a negative effect on egg weight and composition. The ducklings that were restricted in nutrients during their early development, have a reduced BW, and altered lipid and hepatic metabolisms.

Effect of methionine deficiency on the apoptosis and cell cycle of kidney in broilers

Abundant evidence now supports the idea that methionine deficiency has negative effects on chicken healthy especially in the aspect of cell cycle regulation and apoptosis. But, lacking of knowledge is the evaluation on metabolic organs. To test the effect of methionine deficiency on the kidney, we assessed the apoptosis and the cell cycle of kidney induced by methionine deficiency by the methods of TdT-mediated dUTP Nick-End Labeling (TUNEL), flow cytometry (FCM), quantitative real-time PCR (qRT-PCR) and Enzyme-Linked ImmunoSorbent Assay (ELISA) of chickens for 42 days of age. Our results showed that the number of the apoptotic cells was increased (p < .05 or p < .01), while bcl-2 mRNA expression levels were decreased (p < .05 or p < .01) and bax and caspase-3 mRNA expression levels were higher (p < .01) in methionine deficiency group. Furthermore, the cell cycle results showed a time-dependent increase in G2M phase cells and a corresponding decrease in cells at G2M and S stages, the mRNA expression of p53 and p21 was increased (P < .05 or P < .01) and cyclin B and PCNA was significantly lower (P < .05 or P < .01) in the methionine deficiency group than that of the control group. These findings suggested that methionine deficiency could induce renal apoptosis and cell cycle arrest.

Effects of soy protein base diet supplemented with lysine and methionine on digestive enzymes activity and hematological parameters in silvery-black porgy (Sparidentex hasta) juveniles

The effect of dietary partial replacement of fish meal (FM) by soybean protein (SP) alone or in combination with lysine (Lys) and methionine (Met) supplementation were tested in a 60-days feeding trial for silvery-black porgy (Sparidentex hasta) juveniles. Seven isoproteic (ca. 50% crude protein) and isoenergetic (ca. 22.4 MJ/kg) diets were formulated in which 45% (SP45), 60% (SP60) and 75% (SP75) of FM protein were replaced by SP and the control diet (FM) was prepared with FM as the major source of protein. In SP45+, SP60+ and SP75+ diets, 45 to 75% of FM was replaced by SP with supplementing blends of Lys and Met (98% of purity). The activities of the trypsin, lipase and α-amylase were higher in fish fed SP diets with crystalline amino acids supplementation than in the other groups (P < 0.05). Fish fed SP75 and SP75+ diets had the lowest red blood cell count and hematocrit level (P < 0.05). The results of the current study indicated that anti-nutritional factors in a soy-protein based diet rather than lysine and methionine deficiencies may have adverse effects on digestive enzymes activities and health condition in silvery-black porgy juveniles.

Low Protein/low Methionine/high Carbohydrate Diets Induce Hyperphagia, Increase Energy Expenditure and FGF21, but Modestly Affect Adiposity in Female BalbC Mice (OR09-01-19)

ObjectivesLow-protein diets are reported to induce hyperphagia to fulfil protein needs but at the expense of energy balance with a risk to gain in adiposity. However, different studies did not show body fat gain because an increased energy expenditure partly compensated the increase in energy intake and prevents the gain in adiposity. The present study evaluated in mice the consequence of protein restricted diets combined with protein quality (milk protein versus soy protein with slight methionine deficiency) on energy balance and adiposity and the role of FGF21 in the response to the protein restricted diets. MethodsThe study investigated in female BalbC mice the behavioural, metabolic and phenotypic responses to 8 weeks feeding a very low (3% energy - P3), moderately low (6% - P6) or adequate (20% - P20) dietary protein diet and evaluated if methionine scarcity, using soy protein (S) vs casein (C), affected these responses. Food intake, body weight, adiposity (assessed by DEXA), were measured throughout the study and body composition determined at the end of the study. Plasma, liver, muscle, adipose tissue and hypothalamus samples were collected for nutrient, hormones and gene expression measurements. ResultsDecreasing dietary casein from 20% to 3% increased energy intake, slightly increased adiposity, and this was exacerbated with methionine-deficient soy protein (figure 1). Lean body mass was reduced in 3% casein fed mice but preserved in all 6% fed mice. The effect on fat mass was limited because energy expenditure was also increased (figure 2). In plasma, low protein diets decreased IGF-1 and increased FGF21 that was related to protein level, protein to carbohydrate ratio and methionine content in the diet (figure 3). Insulin response to an oral glucose test was reduced in soy and low-protein fed mice. Low-protein diets did not affect Ucp1 but increased Fgf21 in brown adipose tissue and Fgf21, Fas, and Cd36 in the liver. In the hypothalamus, Npy was increased and Pomc was decreased only in 3% casein fed mice. ConclusionsReducing dietary protein and protein quality increases both energy intake and energy expenditure resulting only in slight increase in adiposity. In this process FGF21 is probably a signal that responds to a combination of protein restriction and carbohydrate content of the diet. Funding SourcesInstitut National de la Recherche Agronomique, AgroParisTech. Supporting Tables, Images and/or Graphs▪▪▪

Betaine attenuates pathology by stimulating lipid oxidation in liver and regulating phospholipid metabolism in brain of methionine-choline-deficient rats.

Methyl-donor deficiency is a risk factor for neurodegenerative diseases. Dietary deficiency of the methyl-donors methionine and choline [methionine-choline-deficient (MCD) diet] is a well-established model of nonalcoholic steatohepatitis (NASH), yet brain metabolism has not been studied in this model. We hypothesized that supplemental betaine would protect both the liver and brain in this model and that any benefit to the brain would be due to improved liver metabolism because betaine is a methyl-donor in liver methylation but is not metabolically active in the brain. We fed male Sprague-Dawley rats a control diet, MCD diet, or betaine-supplemented MCD (MCD+B) diet for 8 wk and collected blood and tissue. As expected, betaine prevented MCD diet-induced NASH. However, contrary to our prediction, it did not appear to do so by stimulating methylation; the MCD+B diet worsened hyperhomocysteinemia and depressed liver methylation potential 8-fold compared with the MCD diet. Instead, it significantly increased the expression of genes involved in β-oxidation: fibroblast growth factor 21 and peroxisome proliferator-activated receptor α. In contrast to that of the liver, brain methylation potential was unaffected by diet. Nevertheless, several phospholipid (PL) subclasses involved in stabilizing brain membranes were decreased by the MCD diet, and these improved modestly with betaine. The protective effect of betaine is likely due to the stimulation of β-oxidation in liver and the effects on PL metabolism in brain.-Abu Ahmad, N., Raizman, M., Weizmann, N., Wasek, B., Arning, E., Bottiglieri, T., Tirosh, O., Troen, A. M. Betaine attenuates pathology by stimulating lipid oxidation in liver and regulating phospholipid metabolism in brain of methionine-choline-deficient rats.

Multi-omics characterization of the necrotrophic mycoparasite Saccharomycopsis schoenii.

Pathogenic yeasts and fungi are an increasing global healthcare burden, but discovery of novel antifungal agents is slow. The mycoparasitic yeast Saccharomycopsis schoenii was recently demonstrated to be able to kill the emerging multi-drug resistant yeast pathogen Candida auris. However, the molecular mechanisms involved in the predatory activity of S. schoenii have not been explored. To this end, we de novo sequenced, assembled and annotated a draft genome of S. schoenii. Using proteomics, we confirmed that Saccharomycopsis yeasts have reassigned the CTG codon and translate CTG into serine instead of leucine. Further, we confirmed an absence of all genes from the sulfate assimilation pathway in the genome of S. schoenii, and detected the expansion of several gene families, including aspartic proteases. Using Saccharomyces cerevisiae as a model prey cell, we honed in on the timing and nutritional conditions under which S. schoenii kills prey cells. We found that a general nutrition limitation, not a specific methionine deficiency, triggered predatory activity. Nevertheless, by means of genome-wide transcriptome analysis we observed dramatic responses to methionine deprivation, which were alleviated when S. cerevisiae was available as prey, and therefore postulate that S. schoenii acquired methionine from its prey cells. During predation, both proteomic and transcriptomic analyses revealed that S. schoenii highly upregulated and translated aspartic protease genes, probably used to break down prey cell walls. With these fundamental insights into the predatory behavior of S. schoenii, we open up for further exploitation of this yeast as a biocontrol yeast and/or source for novel antifungal agents.

Methionine-Choline Deprivation Impairs Adult Hippocampal Neurogenesis in C57BL/6 Mice.

Methionine and choline, which are essential nutrients for mammalian animals, are important for cell composition, as metabolic factors, and for the synthesis of other biochemical compounds for cell metabolism. Methionine and choline, which are methyl group donors, play key roles in the homocysteine cycle and neuronal development and maintenance. In this study, we investigated the effects of methionine and choline deficiency on adult hippocampal neurogenesis and neural stem cell (NSC) lineage in the adult stage. For this study, we divided C57BL/6 mice into three groups as follows: normal chow (NC)-fed, methionine choline sufficient (MCS) diet-fed, and methionine choline deficient (MCD) diet-fed mice. The mice were fed the NC, MCS, and MCD diets for 4 weeks from the age of 8 weeks. MCD diet-fed mice showed significantly decreased proliferation and differentiation of NSCs when compared with the NC diet-fed or MCS diet-fed mice. In addition, the survival of newly generated neurons was critically impaired in the MCD diet-fed mice. We confirmed a decrease in the proliferation and differentiation of NSCs after 4 weeks of MCD diet administration, compared with that in NC- and MCS diet-fed mice. MCD diet critically impaired NSCs survival and survival of neurons during the 4 weeks. The number of phosphorylated cyclic AMP response element binding (pCREB) protein immunoreactive nuclei was decreased in the MCD diet-fed mice compared with that in the NC- or MCS diet-fed group. These results suggest that suitable levels of methionine and choline are essential for the maintenance of hippocampal neurogenesis in mice and affect NSC proliferation and differentiation through phosphorylation of CREB.

Effects of Methionine Deficiency on the B Lymphocyte and Immunoglobulins of Cecal Tonsil in Cobb Broilers

ABSTRACT The present study was conducted on one-day-old broilers to investigate the effects of methionine deficiency on B lymphocytes and immunoglobulins (sIgA, IgA, IgG, IgM) in the cecal tonsil of Cobb broiler chicken. Methods including immunohistochemistry (IHC), western blot (WB), quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) and Enzyme-Linked Immuno Sorbent Assay (ELISA) were used, and the study lasted for 6 weeks. It was found that the IgA+ B lymphocytes mainly existed in the diffuse lymphoid tissues and lymphoid follicles of the cecal tonsil. The data indicated that the number of IgA+ B lymphocytes was decreased in the methionine deficiency group, and the WB and qRT-PCR results suggested that the protein and mRNA expression of CD19 were reduced in the methionine deficiency group. Besides, the contents of sIgA, IgA, IgG and IgM determined by ELISA decreased in the methionine deficiency group. It could be concluded that methionine deficiency exerts significantly negative effects on the humoral immune function of the intestinal mucosal immunity.

Early feeding of rainbow trout (Oncorhynchus mykiss) with methionine-deficient diet over a 2week period: consequences for liver mitochondria in juveniles.

Methionine is a key factor in modulating the cellular availability of the main biological methyl donor S-adenosylmethionine (SAM), which is required for all biological methylation reactions including DNA and histone methylation. As such, it represents a potential critical factor in nutritional programming. Here, we investigated whether early methionine restriction at first feeding could have long-term programmed metabolic consequences in rainbow trout. For this purpose, trout fry were fed with either a control diet (C) or a methionine-deficient diet (MD) for 2 weeks from the first exogenous feeding. Next, fish were subjected to a 5month growth trial with a standard diet followed by a 2week challenge (with the MD or C diet) to test the programming effect of the early methionine restriction. The results showed that, whatever the dietary treatment of fry, the 2week challenge with the MD diet led to a general mitochondrial defect associated with an increase in endoplasmic reticulum stress, mitophagy and apoptosis, highlighting the existence of complex cross-talk between these different functions. Moreover, for the first time, we also observed that fish fed the MD diet at the first meal later exhibited an increase in several critical factors of mitophagy, hinting that the early nutritional stimulus with methionine deficiency resulted in long-term programming of this cell function. Together, these data extend our understanding of the role of dietary methionine and emphasize the potential for this amino acid in the application of new feeding strategies, such as nutritional programming, to optimize the nutrition and health of farmed fish.

EFFECT OF SALINITY CHANGES ON METHIONINE CONTENT IN TIGER GROUPER JUVENILE (Epinephelus fuscoguttatus)

This study was conducted to determine the effect of water salinity changes on methionine content in tiger grouper juvenile (Epinephelus fuscoguttatus). A total of 2,560 tiger grouper juveniles were used and divided into five groups consist of 1 control group (without exposed to salinity changes) and 4 treatment groups. The salinity was changed every 2, 3, 4, and 6 hours in treatment A, B, C, and D, respectively. Salinity levels were changed during 24 hours by lowering salinity level from 32 psu to 22 psu. Twenty five of fish were collected from each treatment for methionine content analysis. Data were analysed using one way analysis of variance (ANOVA). The results showed that there was a decrease in methionine content in all treatments. A significant decrease (P0.05) of methionine content in treatment A, B, and C were observed after 20 hours (1.15%), 18 hours (1.27%), and 16 hours (1.24%), respectively. While at 0 hours (control), the methionine content was 2.02%. Methionine level in treatment D was not significantly different (P0.05) compared to control group. As conclusion, rearing the tiger grouper juvenile with salinity fluctuations every 6 hours did not lead to methionine deficiency.

Methionine deficiency decreases hepatic lipid exportation and induces liver lipid accumulation in broilers

The objective of the study was to investigate the effects of deficiency or high level addition of methionine (Met) in diet on homocysteine (Hcy) metabolism and hepatic lipid metabolism in broiler. A completely random design was used with 3 dietary treatments with the addition of Met from DL-methionine (DLM) at 0%, 0.22%, and 0.32% in a basal diet. The analyzed dietary Met was 0.271%, 0.485%, and 0.584% respectively for the Met-deficient, sufficient, and excessive diet. A total of 360 one-day-old male Ross 308 broiler chicks were randomly assigned to the treatments. The trial was last for 21 d. Compared to the Met-sufficient diet, the Met-deficient diet significantly resulted the decrease of 1 to 21 d growth performance and the increase of liver ether extract (EE). Compared to the Met-sufficient group, the expression of lipid transport gene apolipoprotein B (APOB) in both Met-deficient and Met-excessive group was decreased (P < 0.05). However, compared to the Met-sufficient group, a decreased of serum low-density lipoprotein cholesterol (LDLC) was only shown in birds fed a Met-deficient diet (P < 0.05). Although the plasma Hcy content was decreased, the expression of Cystathionine β-synthase (CβS) and hepatic inflammatory cytokines included interleukin-1 (IL-1) and interleukin-8 (IL-8) was significantly decreased in birds fed the Met-deficient diet when compared to those in Met-sufficient group (P < 0.05). When compared to the Met-sufficient group, the broilers in high dietary Met group had increased levels of catabolic enzyme genes expression especially acyl-coenzyme A oxidase 1 (ACOX1) and carbohydrate response element-binding protein (CHREBP) (P < 0.05), and a decreased content of liver EE. In conclusion, dietary Met deficiency decreased the hepatic lipid export and subsequently increased the hepatic lipid accumulation. High dietary Met addition increased the hepatic lipid catabolism and subsequently decreased the liver lipid accumulation.