Curcumin modulates the apolipoprotein B mRNA editing by coordinating the expression of cytidine deamination to uridine editosome components in primary mouse hepatocytes

Curcumin, an active ingredient of Curcuma longa L., can reduce the concentration of low-density lipoproteins in plasma, in different ways. We had first reported that curcumin exhibits hypocholesterolemic properties by improving the apolipoprotein B (apoB) mRNA editing in primary rat hepatocytes. However, the role of curcumin in the regulation of apoB mRNA editing is not clear. Thus, we investigated the effect of curcumin on the expression of multiple editing components of apoB mRNA cytidine deamination to uridine (C-to-U) editosome. Our results demonstrated that treatment with 50 µM curcumin markedly increased the amount of edited apoB mRNA in primary mouse hepatocytes from 5.13%–8.05% to 27.63%–35.61%, and significantly elevated the levels of the core components apoB editing catalytic polypeptide-1 (APOBEC-1), apobec-1 complementation factor (ACF), and RNA-binding-motif-protein-47 (RBM47), as well as suppressed the level of the inhibitory component glycine-arginine-tyrosine-rich RNA binding protein. Moreover, the increased apoB RNA editing by 50 µM curcumin was significantly reduced by siRNA-mediated APOBEC-1, ACF, and RBM47 knockdown. These findings suggest that curcumin modulates apoB mRNA editing by coordinating the multiple editing components of the editosome in primary hepatocytes. Our data provided evidence for curcumin to be used therapeutically to prevent atherosclerosis.

Specificity and inheritance of rBE3 and rBE4 endonuclease-induced gene modifications in rice / 生物工程学报

To gain more insights into the rice base editor (rBE3 and rBE4), we evaluated the mutation efficiency, off-target and inheritance of OsSERK1(D428N) and pi-ta(S918F) genes modified with rBE endonucleases. We predicted and analyzed the putative off-target sites of the sgRNA designed for OsSERK1(D428N) and pi-ta(S918F) by PCR amplification and Sanger sequencing. Then we further characterized the inheritance and stability of targeted base mutations and T-DNA segregation in the progeny of the self-fertilized T0 plants. Analysis of the DNA sequencing data of T0 plants of OsSERK1(D428N) revealed no nucleotide change at any of the four potential off-target sites. For OsSERK1(D428N) and Os08g07774 carry the same sgRNA targeting sites, base substitution at both two loci were detected at a frequency of 41.67%. The targeted base mutations could be transmitted readily to T1 progeny. Furthermore, genetic segregation caused the loss of T-DNA at a frequency between 25.0% and 40.9% in the T1 transgenic plants of OsSERK1(D428N) and pi-ta(S918F). These results demonstrated that the rBE3 and rBE4 systems could mediate specifically targeted base editing in one- or multi-site, and the targeted base editing could be stably inherited to next generation.

The lipid-lowering effect and possible mechanism of apobec-1 in nephrotic syndrome rabbits / 中华实用儿科临床杂志

Objective To observe the effect of liver acquired expression of apobec-1 on blood lipid metabolism, hepatic low density lipoprotein receptor (LDLR), and hepatic low density lipoprotein receptor related protein (LRP) in nephrotic syndrome(NS) rabbits and to explore the lipid-lowering effect and possible mechanism.Methods Thirty healthy ordinary level male new Zealand rabbits were randomly divided into 3 groups:sham operation group (n =10), N S group (n =10), and apobec-1 treatment group (n =10).Adaptive feeding was given for 1 week, then NS group and apobec-1 treatment group underwent left nephrectomy,and 1 week later,adriamycin (4 mg/kg) was used to construct the NS model by way of ear vein injection.In the 11th week after operation, apobec-1 recombinant adenovirus (1 × 1013 virus/kg) was injected through ear vein in apobec-1 treatment group.The 12th week after operation, all rabbits were sacrificed.Right kidney, liver, blood and 24 hour urine were collected.In 3 groups, 24 hour urinary protein (24UPr), albumin (Alb), blood urea nitrogen (BUN), creatinine (Cr), blood lipid were detected.Renal pathology was observed by means of HE staining.Expressions of liver LDLR, LRP were observed by using Western blot.Results (1) There were significant differences among the 3 groups in 24UPr (F =42.778, P =0.000), Alb (F =3.819, P =0.034), BUN (F =6.562, P =0.005), Cr (F =16.076, P =0.000), total cholesterol (TC) (F =17.531, P =0.000), total triglyceride (TG) (F =6.192, P =0.006), very low density lipoprotein (VLDL-C) (F =6.192, P =0.006), low density lipoprotein (LDL-C) (F =34.924, P =0.000) and apolipoprotein B100 (ApoB100) (F =5.180, P =0.012) and apolipoprotein B48 (ApoB48) (F =6.161, P =0.006).(2) Compared with the sham operation group, NS group showed that 24UPr, BUN, Cr, TC, TG, VLDL-C, LDL-C, ApoB100 increased, but Alb decreased, and there was statistical significance (all P ＜ 0.05).(3) Compared with NS group, apobec-1 treatment group showed that TC, TG, VLDL-C, LDL-C, ApoB 100, ApoB48 decreased, and there were statistical significances (all P ＜ 0.05).(4) Compared with the sham operation group, apobec-1 treatment group showed that 24UPr, BUN, Cr increased, but Alb, apolipoprotein B48 (ApoB48) decreased, there were statistical significances (all P ＜ 0.05).(5) There were significant differences of hepatic protein expression among the 3 groups in LRP (F =44.180, P =0.000), LDLR (F =63.141 ,P =0.000).Compared with the sham operation group and NS group, apobec-1 treatment group showed that the expression of LRP was up-regulated (P ＜ 0.01,0.05), while the expression of LDLR was down-regulated (all P ＜ 0.05).Conclusions When liver acquired expression of apobec-1 in NS, it could up-regulate LRP,accelerate the elimination of ApoB48-lipoproteins, and produce a certain lipid-lowering effect.

Genetic Variation in Exon 3 of Human Apo B mRNA Editing Protein (apobec-1) Gene

We have investigated the genetic variation in the human apo B mRNA editing protein (apobec-1) gene. Exon 3 of the apobec-1 gene was amplified by polymerase chain reaction. After detection of an additional band by single strand conformational polymorphism (SSCP) analysis, sequencing of the SSCP shift sample revealed a single-base mutation. The mutation was a CGG transversion at codon 80 resulting in a lleRMet substitution. Thes substitution was confirmed by restriction fragment length polymorphism analysis since a pvull site is abolished by the substitution. Population and family studies confirmed that the inheritance of the genotypes for apobec-1 gene polyomrphism is comtrolled by two codominant alleles (P1 and P2). A significant difference in plasma triglyceride was detected among the different apobec-1 genotypes in the CAD patients (P<0.05) Our study could provide the basis for elucidating the interaction between gentic variation of the apobec-1 gene and disorders related to lipid metabolism.