Lipid Metabolism Genes in Stroke Pathogenesis: The Atherosclerosis.

Stroke is the second leading cause of death and a major cause of disability worldwide. Both modifiable and non-modifiable risk factors can affect the occurrence of ischemic stroke at varying degrees. Among them, atherosclerosis has been well-recognized as one of the main culprits for the rising incidence of stroke-related mortality. Hence, the current review aimed to summarize the prominent role of lipid metabolism genes such as PCSK9, ApoB, ApoA5, ApoC3, ApoE, and ABCA1 in mediating ischemic stroke occurrence.

Transgenerational lipid-reducing activity of benzylisoquinoline alkaloids in Caenorhabditis elegans.

Epigenetic mechanisms allow for transgenerational memory of an ancestor's environment and can affect the gene expression, physiology and phenotype of that ancestor's descendants, independent of DNA sequence alteration. Among many model organisms, Caenorhabditis elegans has been instrumental in studies of transgenerational inheritance, most of which have focused on the effects of external stressors of the parent worm on the life span and stress resistance of future generations. In this work, we used Nile red staining of accumulated lipids in C. elegans to investigate the transgenerational effect of two benzylisoquinoline alkaloids, namely, berberine and sanguinarine. Our results showed that a reduction in Nile red fluorescence can be propagated to subsequent worm generations. Using mutant worms, we found that the transgenerational effect requires the ASH-2 component of the histone H3K4me3 complex and the HRDE-1 worm Argonaute protein. Ash-2 is also required for transgenerational inheritance of the xenobiotic response in the worm. Our study offers new insights into transmissible drug effects across multiple generations and suggests the importance of such analyses in the drug development process.

Data set of differentially expressed microRNAs in sanguinarine-treated Caenorhabditis elegans and its F3 progeny.

This article presents small RNA sequencing data of Caenorhabditis elegans consist of P0 control worms (untreated), P0 worms treated with a plant alkaloid, sanguinarine, and its F3 offspring. The data were analyzed to identify microRNAs that were differentially expressed in both the sanguinarine-treated P0 and its descendants F3 worms. Targets of the identified miRNAs, gene function annotations and their functional clusters are shown. The data presented here will facilitate comparison with data from other researchers who are working on miRNAs profiling of xenobiotic-treated C. elegans.

Dihydrosanguinarine Enhances Glucose Uptake in Mouse 3T3-L1 Cells.

Recently, more studies have aimed at identifying selective peroxisome proliferator-activated receptor gamma (PPARγ) modulators that transactivate the expression of PPARγ-dependent genes as partial agonists to improve diabetic symptoms with fewer side effects compared to classic PPARγ agonists such as thiazolidinediones. We found that dihydrosanguinarine (DHS) treatment induced preadipocyte differentiation and lipid droplet accumulation in 3T3-L1 cells, but this effect is weaker than that elicited by the full PPARγ agonist troglitazone. Furthermore, this effect was reduced by the addition of a PPARγ antagonist, indicating the involvement of PPARγ signaling. Our results suggest that the stimulatory effects of DHS on adipocyte differentiation and insulin sensitivity are mediated by suppressing adenosine monophosphate-activated protein kinase (AMPK) alpha, upregulating the expression of PPARγ and its target genes (particularly Glut-4 and adiponectin) and reducing PPARγ phosphorylation. DHS significantly enhanced the glucose uptake in 3T3-L1 adipocytes without observable cytotoxicity at the effective concentration (5 µM) applied.

13-Methylberberine, a berberine analogue with stronger anti-adipogenic effects on mouse 3T3-L1 cells.

Lipid metabolism modulation is a main focus of metabolic syndrome research, an area in which many natural and synthetic chemicals are constantly being screened for in vitro and in vivo activity. Berberine, a benzylisoquinoline plant alkaloid, has been extensively investigated for its anti-obesity effects and as a potential cholesterol and triglyceride-lowering drug. We screened 11 protoberberine and 2 benzophenanthridine alkaloids for their anti-adipogenic effects on 3T3-L1 adipocytes and found that 13-methylberberine exhibited the most potent activity. 13-Methylberberine down-regulated the expression of the main adipocyte differentiation transcription factors, peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα), as well as their target genes. PPARγ, C/EBPα, and sterol regulatory element binding protein 1 (SREBP-1) protein levels were reduced, and this lipid-reducing effect was attenuated by an AMP-activated protein kinase (AMPK) inhibitor, indicating that the effect of this compound requires the AMPK signaling pathway. Decreased Akt phosphorylation suggested reduced de novo lipid synthesis. C-13 methyl substitution of berberine increased its accumulation in treated cells, suggesting that 13-methylberberine has improved absorption and higher accumulation compared to berberine. Our findings suggest that 13-methylberberine has potential as an anti-obesity drug.

Knockdown of the NHR-8 nuclear receptor enhanced sensitivity to the lipid-reducing activity of alkaloids in Caenorhabditis elegans.

Caenorhabditis elegans is a versatile, whole-organism model for bioactivity screening. However, this worm has extensive defensive mechanisms against xenobiotics which limit its use for screening of pharmacologically active compounds. In this study, we report that knockdown of nhr-8, a gene involved in the xenobiotic response, increased the worm's sensitivity to the lipid-reducing effects of some isoquinoline alkaloids, especially berberine. On the other hand, crude extract of rhizome and cultured cells showed enhanced biological activity compared to the pure alkaloids in wild type worm, but this enhanced activity was not detected in nhr-8 RNAi worm, suggesting that some components in cell extracts might interfere with the defense response in this worm. The possibility of using C. elegans as a model for screening bioactive chemicals is discussed.

Screening of isoquinoline alkaloids for potent lipid metabolism modulation with Caenorhabditis elegans.

Metabolic syndrome and related disorders are increasingly prevalent in contemporary society, and thus pose the need for potent agents to control lipid accumulation in the body. This study indicates that Caenorhabditis elegans was effective in screening for potent lipid metabolism modulators with berberine as a model compound. Among the various isoquinoline alkaloids tested, sanguinarine, a benzophenanthridine alkaloid, was found to be the most potent. Sanguinarine, like berberine, reduced lipid accumulation through AMP-activated protein kinase activation. Analysis of AMPK (aak-1 and aak-2) RNAi worms revealed that effects were aak-2-dependent. Characterization of worms with knockdown nhr-49, a hormone nuclear receptor gene that functions as a key regulator of fat consumption, showed that both alkaloids were effective even in these markedly lipid-accumulating nhr-49 RNAi worms, suggesting that they predominantly affect lipid synthesis, rather than fatty acid ß-oxidation. The versatility of C. elegans for the purpose of lipid-modulating chemical screening and characterization of the underlying mechanisms is discussed.

Over-expression of rate-limiting enzymes to improve alkaloid productivity.

Benzylisoquinoline alkaloids are one of the most important groups of secondary metabolites and include the economically important analgesic morphine and the antimicrobial agent berberine. To improve the productivity of these alkaloids, we investigated the effects of putative rate-limiting step enzymes in alkaloid biosynthesis. We constructed several over-expression vectors for biosynthetic enzymes and introduced them into cultured California poppy, a model isoquinoline alkaloid-producing plant. HPLC/LC-MS analysis of transgenic cells revealed that these enzymes varied in their ability to increase alkaloid production. We describe the use of a rate-limiting step gene to improve alkaloid productivity.