RESUMO
[Objective]To investigate the effects of different doses of anthocyanins Cy-3-g on serum lipids,platelet-derived chemokines,including MIF and CXCL12 together with their receptors CXCR4 and CXCR7.[Methods]Male ApoE-/-mice were distributed to 5 groups(n=15 per group),and fed with standard diet,high fat diet(HFD),HFD with 200 mg/kg Cy-3-g(low),HFD with 400 mg/kg Cy-3-g(middle),HFD with 800 mg/kg Cy-3-g(high)respectively for 16 weeks. The changes of body weight and food intake were recorded weekly. At the end of the experiment term,the serum lipids(triglyceride,cholesterol,HDL-C,LDL-C)were detected by kits. Arteries were separated to determine plaque histology by Oil-Red-O stain.MIF,CXCL12 and CCL2 in serum were detected by ELISA kits.The expression of CXCR4 and CXCR7 on the surface of leukocytes were tested via flow cytometry. Tail bleeding time was measured mean-while.[Results]Compared with the HFD group,the levels of serum lipids in medium(400 mg/kg)and high(800 mg/kg)Cy-3-g groups were significantly decreased(P<0.05). The plaque area of carotid artery was decreased in high Cy-3-g group(P<0.05).Cy-3-g at all doses significantly reduced the serum concentrations of CXCL12 and CCL2(P<0.002).Cy-3-g of medium(400 mg/kg)and high(800 mg/kg)dose significantly inhibited the expression of CXCR4 and CXCR7 on leukocyte surface(P<0.05). Cy-3-g does not prolong the tail bleeding time.[Conclusions]Anthocyanin Cy-3-g inhibits chemokine CXCL12,CCL2 in serum,and the expression of CXCR4 and CXCR7 on leukocytes without bleeding risk in ApoE-/-mice.
RESUMO
The RNA-directed DNA Methylation (RdDM) is one type of epigenetic modification which was firstly discovered in plant. RdDM can directly cause DNA modifications of the genome through RNA-DNA interactions. In plant, both of RdDM and mRNA degradation induced by siRNA can silence sequence specific genes through RNA. They play very significant roles in chromosome rearrangement, defence of virus invasion, regulation of gene expression and many processes of plant development. However, the mechanisms of RdDM are still unclear. In this paper the basic characteristics of RdDM were briefly summarized and advances in studies on mechanisms of RdDM were reviewed. These include the kinds of DNA methyltransferases and their functional mechanisms in RdDM, the relationships between DNA methylation and chromatin modification, and important proteins involved in the RdDM process. In plants, RdDM may occur at both the transcriptional and post-transcriptionnal levels, both of which induce gene silencing. Methylation of the target gene promoter correlates with transcriptional gene silencing (TGS) whereas methylation of the coding sequence is associated with post-transcriptional gene silencing (PTGS). RdDM and RNAi all depend on the similar siRNA and enzymes, such as DCL3, RdR2, SDE4 and AGO4. There are at least three kinds of DNA methyltransferases, DRM1/2, MET1 and CMT3, in pants. They can interact with and modifies all cytidines within the DNA regions homologous to RNA sequence. Furthermore, methylation of lysine 9 in Histone H3 can affect the methylation of cytidines.
