Leucosceptroid B from glandular trichomes of Leucosceptrum canum reduces fat accumulation in Caenorhabditis elegans through suppressing unsaturated fatty acid biosynthesis / 中国天然药物

Obesity that is highly associated with numerous metabolic diseases has become a global health issue nowdays. Plant sesterterpenoids are an important group of natural products with great potential; thus, their bioactivities deserve extensive exploration. RNA-seq analysis indicated that leucosceptroid B, a sesterterpenoid previously discovered from the glandular trichomes of Leucosceptrum canum, significantly regulated the expression of 10 genes involved in lipid metabolism in Caenorhabditis elegans. Furthermore, leucosceptroid B was found to reduce fat storage, and downregulate the expression of two stearoyl-CoA desaturase (SCD) genes fat-6 and fat-7, and a fatty acid elongase gene elo-2 in wild-type C. elegans. In addition, leucosceptroid B significantly decreased fat accumulation in both fat-6 and fat-7 mutant worms but did not affect the fat storage of fat-6; fat-7 double mutant. These findings indicated that leucosceptroid B reduced fat storage depending on the downregulated expression of fat-6, fat-7 and elo-2 and thereby inhibiting the biosynthesis of the corresponding unsaturated fatty acid. These findings provide new insights into the development and utilization of plant sesterterpenoids as potential antilipemic agents.

Hydroxysafflor yellow A repairing the metabolic disturbances of early atherosclerosis based on fatty acid profiling / 药学学报

Atherosclerosis (AS) is a complex metabolic syndrome that seriously harms human health, and its occurrence and development are directly related to the metabolic disturbances of free fatty acids (FFA). In this study, macrophage-derived foam cells were established as the model of early AS. Therefore, the metabolic disturbances of FFA in ox-LDL induced foamy macrophages were analyzed using target metabolomics. Then the effect of hydroxysafflor yellow A (HSYA) on regulating FFA was also explored. The quantitative analysis of 27 fatty acids was obtained within 20 min based on dynamic MRM mode. Thirteen metabolic biomarkers of macrophage-derived foam cells were identified using multivariate statistical analysis. It was found that upregulation of total SFA and downregulation of C12:0, C14:0, C18:1, total MUFA were the typical metabolic features in macrophage-derived foam cells. Furthermore, HSYA displayed obvious repairing effect on C12:0, C14:0 and C18:1, which were involved in de novo fatty acid biosynthesis pathway. Oleoyl-(acyl-carrier-protein) hydrolase (OLAH), as the key enzyme in de novo fatty acid biosynthesis pathway, may be a drug target of HSYA.

Role of Stargardt type Ⅲ macular dystrophy gene ELOVL4 in fatty acids metabolism / 中华实验眼科杂志

Background Researches determined that ELOVL4 gene is a disease-causing gene of Stargard tmacular dystrophy and is a elongation enzyme of very long chain fatty acids.Stargardt type Ⅲ(STGD3) may be associated with the metabolism of extensive enzyme of very long chain fatty acids.To explore the effect of ELOVL4 in STGD3 and its relationship with the metabolism of extensive enzyme of very long chain fatty acids is of important clinical significance.Objective This study was to determine the role of ELOVL4 gene for the pathogenesis of STGD3.Methods Recombinant adenovirus type 5 carrying mouse ELOVL4 gene and green fluorescent protein (GFP) was transfected into pheochromocytoma cells (PC12 cells),and then the cells were divided into PC12 group,PC12+Ad5-GFP group and PC12+AdS-ELOVL4 group.Ad-GFP or Ad-ELOVL4 was added into the culture medium for 24 hours with the virus plasmid 1 × 104-2× 104 pfu/ml.Expression of ELOVL4 mRNA in the PC12 was quantified by quantitative real time PCR(qRT-PCR) and was described as relative value to the expression of RPL19.ELOVL4 protein was assayed by Western blot.The transfected cells were treated with arachidonic acid (AA,20:4n6),eicosapentaenoic acid (EPA,20:5n3) and docosahexaenoic acid (DHA,22:6n3) individually for 48 hours.The cells were collected,and total lipids were extracted,and fatty acid methyl esters were prepared and analyzed by gas chromatography-mass spectrometry (GC-MS).Results The relative expression levels of ELOVL4 mRNA in PC12 cells in the PC12+Ad5-ELOVL4 group,PC12+Ad5-GFP group and PC12 group were 0.833± O.138,0.027t±0.002 and 0.024 ±0.002,with a significant difference among the 3 groups (F =102.700,P =0.000),and relative expression levels of PC12+Ad-ELOVL4 were 30-40 folds more than those in the PC12 group and the PC12+Ad-GFP group.Western blot assay showed a stronger response band for ELOVL4 protein in the PC12+Ad-ELOVL4 group.GC-MS found that abundant polyunsaturated fatty acids (C28-C38) were synthesized by PC12 cells in the PC12+Ad-ELOVL4 group,with the more levels in C34 and C36.Conclusions ELOVL4 can promote the synthesis of C28-C38 polyunsatured fatty acid in PC12 cells,which offers a novel clue for the treatment of STGD3.

HCV NS5A and NS5B Enhance Expression of Human Ceramide Glucosyltransferase Gene / 中国病毒学·英文版

Host genes involved in lipid metabolism are differentially affected during the early stages of hepatitis C virus (HCV) infection.Here we demonstrate that artificial up-regulation of fatty acid biosynthesis has a positive effect on the replication of the HCV full-length replicon when cells were treated with nystatin.Conversely,the HCV RNA replication was decreased when fatty acid biosynthesis was inhibited with 25-hydroxycholesterol and PDMP(D-threo-1-phenyl-2-decanoylamino-3- morpholino-1-propanol).In agreement with these results,the expression level of GlcT-1(ceramide glucosyltransferase),a host glucosyltransferase in the first step of GSL (glycosphingolipid) biosynthesis,was found to be closely associated with the expression and replication of HCV RNA.On the other hand,the viral RNA can also activate GlcT-1 in the early stage of viral RNA transfection in vitro.To identify viral factors that are responsible for GlcT-1 activation,we constructed ten stable Vero cell lines that express individual HCV proteins.Based on the analyses of these cell lines and transient transfection assay of the GlcT-1 promoter regions,we conclude that HCV proteins,especially NS5A and NS5B,have positive effects on the expression of GlcT-1.It is possible that NS5A and NS5B stimulate transcription factor(s) to activate the expression of GlcT-1 by increasing its transcription level.

Fatty acid synthesis by isolated leucoplasts from developing Brassica seeds: Role of nucleoside triphosphates and DHAP-shuttle as the source of energy.

Fatty acid synthesis in leucoplasts isolated from developing seeds of Brassica campestris was absolutely dependent on external source of ATP. None of the other nucleoside triphosphates could replace ATP in the reaction mixture. Use of ADP alone also resulted in reduced rates of fatty acid synthesis. However, in combination with inorganic phosphate or inorganic pyrophosphate, it improved the rate of fatty acid synthesis, giving up to 50% of the ATP-control activity. Inorganic phosphate or inorganic pyrophosphate alone again did not serve as an energy source for fatty acid synthesis. AMP, alongwith inorganic pyrophosphate could promote fatty acid synthesis to up to 42% of the activity obtained with ATP. The three components dihydroxy acetone phosphate, oxaloacetic acid, inorganic phosphate of dihydroxy acetone phosphate-shuttle together could restore 50% of the activity obtained with ATP. Omission of any one of the components of this shuttle drastically reduced the rate of fatty acid synthesis to 15–24% of the ATP-control activity. Inclusion of ATP in reaction mixtures containing shuttle components enhanced the rate of synthesis over control. The optimum ratio of shuttle components dihydroxy acetone phosphate, oxaloacetic acid, inorganic phosphate determined was 1:1:2. Maximum rates of fatty acid synthesis were obtained when dihydroxy acetate phosphate was used as the shuttle triose. Glyceraldehyde-3-P, 3-phosphoglycerate, 2-phosphoglycerate and phosphoenolpyruvate as shuttle trioses were around 35–60% as effective as dihydroxy acetone phosphate in promoting fatty acid synthesis. The results presented here indicate that although the isolated leucoplasts readily utilize exogenously supplied ATP for fatty acid synthesis, intraplastidic ATP could also arise from dihydroxy acetone phosphate shuttle components or other appropriate metabolites.