Effect of Methionine Deficiency on the Thymus and the Subsets and Proliferation of Peripheral Blood T-Cell,and Serum IL-2 Contents in Broilers

The purpose of this study was to investigate the effects of methionine deficiency on cellular immune function by determining morphological and ultrastructural changes of thymus, thymic cell cycle and apoptosis, peripheral blood T-cell subsets, T- cell proliferation function and the serum interleukin-2 （IL-2） contents. 120 1-d-old broilers were randomly divided into two groups （6 replicates in each group and l0 broilers in each replicate） and fed on a control diet or methionine deficient diet for 42 d. Lesions were observed in experiment. Histopathologically, lymphopenia and congestion were observed in the medulla of thymic lobule. Ultrastructurally, there were more apoptosis lymphocytes, and the mitochondria of lymphocytes were swelled in thymus of methionine deficiency. The G0/G~ phase of the cell cycle of the thymus was much higher （P〈0.01）, and the S, G2＋M phases and proliferating index （PI） were lower （P〈0.01） in methionine deficiency than in control group. And the percentage of apoptotic cells in the thymus was significantly increased in methionine deficiency （P〈0.01）. The percentage of CD4＋ and CD8~ T-cells was decreased in methionine deficiency compared with control group. Meanwhile, the proliferation function of peripheral blood T-cell was decreased in methionine deficiency. Also, the serum IL-2 contents were decreased in methionine deficiency. It was concluded that methionine deficiency could cause pathological and ultrastructural changes of thymus, reduce the T-cell population, serum IL-2 contents and the proliferation function of T- cells, and induce increased percentage of apoptotic cells. The cellular immune function was finally impaired in broilers.

Dietary methionine deficiency stunts growth and increases fat deposition via suppression of fatty acids transportation and hepatic catabolism in Pekin ducks

Background:Although methionine(Met),the first-limiting dietary amino acid,has crucial roles in growth and regulation of lipid metabolism in ducks,mechanisms underlying are not well understood.Therefore,the objective was to use dietary Met deficiency to investigate the involvement of Met in lipid metabolism and fat accumulation of Pekin ducks.Methods:A total of 150 male Pekin ducks(15-d-old,558.5±4.4 g)were allocated into 5 groups(6 replicates with 5 birds each)and fed corn and soybean meal-based diets containing 0.28%,0.35%,0.43%,0.50%,and 0.58%Met,respectively,for 4 weeks.Met-deficient(Met-D,0.28%Met)and Met-adequate(Met-A,0.43%Met)groups were selected for subsequent molecular studies.Serum,liver,and abdominal fat samples were collected to assess the genes and proteins involved in lipid metabolism of Pekin ducks and hepatocytes were cultured in vivo for verification.Results:Dietary Met deficiency caused growth depression and excess fat deposition that were ameliorated by feeding diets with adequate Met.Serum triglyceride and non-esterified fatty acid concentrations increased(P<0.05),whereas serum concentrations of total cholesterol,low density lipoprotein cholesterol,total protein,and albumin decreased(P<0.05)in Met-D ducks compared to those in Met-A ducks.Based on hepatic proteomics analyses,dietary Met deficiency suppressed expression of key proteins related to fatty acid transport,fatty acid oxidation,tricarboxylic acid cycle,glycolysis/gluconeogenesis,ketogenesis,and electron transport chain;selected key proteins had similar expression patterns verified by qRT-PCR and Western blotting,which indicated these processes were likely impaired.In vitro verification with hepatocyte models confirmed albumin expression was diminished by Met deficiency.Additionally,in abdominal fat,dietary Met deficiency increased adipocyte diameter and area(P<0.05),and down-regulated(P<0.05)of lipolytic genes and proteins,suggesting Met deficiency may suppress lipolysis in adipocyte.Conclusion:Taken together,these data demonstrated that dietary Met deficiency in Pekin ducks resulted in stunted growth and excess fat deposition,which may be related to suppression of fatty acids transportation and hepatic catabolism.

Arachidyl amido cholanoic acid improves liver glucose and lipid homeostasis in nonalcoholic steatohepatitis via AMPK and mTOR regulation

BACKGROUND Arachidyl amido cholanoic acid(Aramchol)is a potent downregulator of hepatic stearoyl-CoA desaturase 1(SCD1)protein expression that reduces liver triglycerides and fibrosis in animal models of steatohepatitis.In a phase IIb clinical trial in patients with nonalcoholic steatohepatitis(NASH),52 wk of treatment with Aramchol reduced blood levels of glycated hemoglobin A1c,an indicator of glycemic control.AIM To assess lipid and glucose metabolism in mouse hepatocytes and in a NASH mouse model[induced with a 0.1%methionine and choline deficient diet(0.1MCD)]after treatment with Aramchol.METHODS Isolated primary mouse hepatocytes were incubated with 20μmol/L Aramchol or vehicle for 48 h.Subsequently,analyses were performed including Western blot,proteomics by mass spectrometry,and fluxomic analysis with 13C-uniformly labeled glucose.For the in vivo part of the study,male C57BL/6J mice were randomly fed a control or 0.1MCD for 4 wk and received 1 or 5 mg/kg/d Aramchol or vehicle by intragastric gavage for the last 2 wk.Liver metabolomics were assessed using ultra-high-performance liquid chromatography-time of flight-MS for the determination of glucose metabolism-related metabolites.RESULTS Combination of proteomics and Western blot analyses showed increased AMPK activity while the activity of nutrient sensor mTORC1 was decreased by Aramchol in hepatocytes.This translated into changes in the content of their downstream targets including proteins involved in fatty acid(FA)synthesis and oxidation[PACCα/β(S79),SCD1,CPT1A/B,HADHA,and HADHB],oxidative phosphorylation(NDUFA9,NDUFB11,NDUFS1,NDUFV1,ETFDH,and UQCRC2),tricarboxylic acid(TCA)cycle(MDH2,SUCLA2,and SUCLG2),and ribosome(P-p70S6K[T389]and P-S6[S235/S236]).Flux experiments with 13Cuniformely labeled glucose showed that TCA cycle cataplerosis was reduced by Aramchol in hepatocytes,as indicated by the increase in the number of rounds that malate remained in the TCA cycle.Finally,liver metabolomic analysis showed that glucose homeostasis was improved by Aramchol in 0.1MCD fed mice in a dose-dependent manner,showing normalization of glucose,G6P,F6P,UDP-glucose,and Rbl5P/Xyl5P.CONCLUSION Aramchol exerts its effect on glucose and lipid metabolism in NASH through activation of AMPK and inhibition of mTORC1,which in turn activate FAβ-oxidation and oxidative phosphorylation.

Elevated free cholesterol in a p62 overexpression model of non-alcoholic steatohepatitis

AIM: To characterize how insulin-like growth factor 2 (IGF2) mRNA binding protein p62/IMP2-2 promotes steatohepatitis in the absence of dietary cholesterol.