Search

Methylation plays a vital role in biological systems. SAM ( S -adenosyl-L-methionine), an abundant cofactor in life, acts as a methyl donor in most biological methylation reactions. SAM-dependent methyltransferases (MTase) transfer a methyl group from SAM to substrates, thereby altering their physicochemical properties or biological activities. In recent years, many SAM analogues with alternative methyl substituents have been synthesized and applied to methyltransferases that specifically transfer different groups to the substrates. These include functional groups for labeling experiments and novel alkyl modifications. This review summarizes the recent progress in the synthesis and application of SAM methyl analogues and prospects for future research directions in this field.

Objective To investigate the therapeutic effect of bone marrow cell adoptive therapy on metabolic-dysfunction-associated fatty liver disease (MAFLD) in mice and its possible cell population. Methods The staining was used to detect the liver lesions of MAFLD in C57BL/6 mice induced by methionine and choline deficiency diet (MCD) and the adoptive therapeutic effect of bone marrow cells on MAFLD was evaluated by detecting the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The mRNA expressions of low density lipoprotein receptor (LDLR) and interleukin-4 (IL-4) in liver immune cells (including T, NKT, Kupffer cells and other cell populations) were detected by real-time quantitative PCR. The bone marrow cells labeled with 5, 6- carboxyfluorescein diacetate succinimidyl ester (CFSE) were injected into the tail vein of mice. The proportion of CFSE positive cells in liver tissue was observed by the frozen section, and the proportion of labeled cells in the liver and spleen was tracked by flow cytometry. The expression of CD3, CD4, CD8, NK1.1, CD11b and Gr-1 in CFSE labeled adoptive cells was detected by flow cytometry. The intracellular lipid content of NKT cells in liver tissue was evaluated by Nile Red lipid staining. Results The injury of liver tissue and the levels of serum ALT and AST in MAFLD mice were significantly reduced. At the same time, liver immune cells up-regulated the expression of IL-4 and LDLR. LDLR knockout mice induced more severe MAFLD after giving MCD diet. Bone marrow adoptive cells had a significant therapeutic effect and differentiated more NKT cells to colonize the liver. At the same time, the intracellular lipids of these NKT cells increased significantly. Conclusion Bone marrow cell adoptive therapy can reduce liver injury in MAFLD mice by differentiating more NKT cells and increasing the intracellular lipid content of these cells.

Objective: To investigate the alleviating effect of hydrogen (H 2 ) on homocysteine (Hcy) levels and non alcoholic fatty liver in rats with hyperhomocysteinemia (HHcy). Methods: After one week of adaptive feeding, Wistar rats were randomly divided into three groups: the general diet group (CHOW), the high methionine group (HMD), and the high methionine plus hydrogen rich water group (HMD+HRW), with 8 rats in each group. The CHOW group was fed with AIN-93G feed, while the HMD and HMD+HRW groups were fed with AIN-93G+2% methionine feed to construct an HHcy model. The HMD+HRW group was also gavaged with hydrogen rich water (3 ml/animal, twice a day, with a hydrogen concentration of 0.8 mmol/L), and body weight data were recorded. After 6 weeks of feeding, the plasma and liver samples were processed and collected. The plasma homocysteine (Hcy) and lipid contents of each group were measured, and the histological morphology of the liver was observed. The activities of key enzymes in the Hcy metabolism pathway and mRNA expression were detected in the liver. Results: Compared with the CHOW group rats, the Hcy level in the blood of HMD rats was significantly increased significantly ( P ＜0.05). Pathological tissue sections showed liver enlargement, injury, and fatty liver in the rats; Compared with the HMD group rats, the HMD+HRW group rats showed a significant decrease in Hcy in the blood, reduced liver damage, and increased Hcy metabolism key enzyme activity and mRNA expression in the liver, with statistical differences ( P ＜0.05). Conclusion: Hydrogen has a significant improvement effect on liver injury induced by HMD diet in HHcy rats, possibly by enhancing the three metabolic pathways of Hcy to reduce excessive Hcy in the body, thereby improving liver metabolic function and symptoms of non-alcoholic fatty liver disease.