Berberine Enhances Intestinal Mucosal Barrier Function by Promoting Vitamin D Receptor Activity.

OBJECTIVE: To evaluate if berberine can act on vitamin D receptors (VDR) and thereby regulate the expression of tight junction proteins (TJPs) in irritable bowel syndrame-diarrhea-predominant (IBS-D) rats. METHODS: The newborn rats were induced into IBS-D rat model via neonatal maternal separation combined with acetic acid chemical stimulation. After modeling, the model was evaluated and rats were divided into the control group and berberine treatment groups (0.85, 1.7 and 3.4 mg/kg, once a day for 2 weeks). The distal colon was obtained and colonic epithelial cells (CECs) were isolated and cultured after IBS-D model evaluation. The vitamin D receptor response element (VDRE) reporter gene was determined in the CECs of IBS-D rats to analyze the effect of berberine on the VDRE promoter. VDR overexpression or silencing technology was used to analyze whether VDR plays a role in promoting intestinal barrier repair, and to determine which region of VDR plays a role in berberine-regulated intestinal TJPs. RESULTS: The IBS-D rat model was successfully constructed and the symptoms were improved by berberine in a dose-dependent manner (P<0.05). The activity of VDRE promoter was also effectively promoted by berberine (P<0.05). Berberine increased the expression of TJPs in IBS-D CECs (P<0.05). VDR expression was significantly increased after transfection of different domains of VDR when compared to normal control and basic plasmid groups (all P<0.05). RT-qPCR and Western blot results showed that compared with the blank group, expressions of occludin and zonula occludens-1 were significantly higher in VDR containing groups (all P<0.05). Berberine plus pCMV-Myc-VDR-N group exerted the highest expression levels of occludin and zonula occludens-1 (P<0.05). CONCLUSION: Berberine enhances intestinal mucosal barrier function of IBS-D rats by promoting VDR activity, and the main site of action is the N-terminal region of VDR.

Metastatic colon cancer treated using traditional Chinese medicine combined with chemotherapy: A case report.

BACKGROUND: Colon cancer (CC) is one of the leading causes of cancer-related morbidity and mortality worldwide. Traditional Chinese medicine (TCM) is widely used in the treatment of various chronic diseases. CC easily metastasizes and results in high morbidity and mortality rates. CASE SUMMARY: A 71-year-old man with a 12-year history of old myocardial infarction and a 7-year history of type 2 diabetes mellitus was diagnosed with CC and underwent right hemicolectomy 1 year ago. Tumor biopsy revealed moderately poorly differentiated adenocarcinoma. Subsequently, chemotherapy with oxaliplatin and paclitaxel was administered. Anastomosis recurrence and pelvic metastasis were noted 37 d later. The patient received eight 21-d cycles of adjuvant chemotherapy with oxaliplatin and capecitabine after recurrence. However, the tumor persisted, and chemotherapy-related liver damage developed gradually. Thus, he was advised to take TCM for the recurrence and pelvic metastasis. The patient's metastatic CC was cured after receiving TCM combined with long-term chemotherapy. CONCLUSION: TCM may be an effective adjunct therapy in the treatment of patients with metastatic CC.

Site-directed mutagenesis identified the key active site residues of 2,3-oxidosqualene cyclase HcOSC6 responsible for cucurbitacins biosynthesis in Hemsleya chinensis.

Hemsleya chinensis is a Chinese traditional medicinal plant, containing cucurbitacin IIa (CuIIa) and cucurbitacin IIb (CuIIb), both of which have a wide range of pharmacological effects, including antiallergic, anti-inflammatory, and anticancer properties. However, few studies have been explored on the key enzymes that are involved in cucurbitacins biosynthesis in H. chinensis. Oxidosqualene cyclase (OSC) is a vital enzyme for cyclizing 2,3-oxidosqualene and its analogues. Here, a gene encoding the oxidosqualene cyclase of H. chinensis (HcOSC6), catalyzing to produce cucurbitadienol, was used as a template of mutagenesis. With the assistance of AlphaFold2 and molecular docking, we have proposed for the first time to our knowledge the 3D structure of HcOSC6 and its binding features to 2,3-oxidosqualene. Mutagenesis experiments on HcOSC6 generated seventeen different single-point mutants, showing that single-residue changes could affect its activity. Three key amino acid residues of HcOSC6, E246, M261 and D490, were identified as a prominent role in controlling cyclization ability. Our findings not only comprehensively characterize three key residues that are potentially useful for producing cucurbitacins, but also provide insights into the significant role they could play in metabolic engineering.

Supplementation with Tribulus Terrestris Extract Exhibits Protective Effects on MCAO Rats via Modulating Inflammation-Related Metabolic and Signaling Pathways.

The extract of Tribulus terrestris (TT) has been used as a component of several nutritional supplements for enhancing human vitality. However, its protective effect on ischemic stroke has yet to be fully investigated. In this study, the middle cerebral artery occlusion (MCAO) rat model was established and treated with gross saponin of TT fruit (GSTTF) by gavage to explore its anti-ischemic stroke efficacy. Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics was applied to profile the brain tissue metabolite changes and further obtain the metabolic pathways that were greatly involved in the efficacy of GSTTF. Subsequent molecular biology experiments were applied to validate the findings from metabolomics analysis. The results showed that GSTTF administration remarkably decreased the infarction volume of brain tissue and improved the neurobehavioral scores of MCAO rats. Metabolomics analysis revealed that pathways, including glycerophospholipid metabolism, sphingolipid metabolism, and arachidonic acid metabolism, were considered associated with the protective effect of GSTTF against MCAO, which were greatly involved in the inflammatory responses. The results of the biochemistry analysis showed that GSTTF treatment significantly reduced the levels of TNF-α and IL-6 in brain tissue after MCAO. The anti-inflammatory mechanism of GSTTF was further investigated, which revealed that GSTTF could inhibit the TLR4/MyD88/NF-κB signaling pathway to exert protective effects on MCAO. This study provides the underlying anti-inflammatory mechanism of GSTTF for ischemic stroke protection, which has important implications for the development of GSTTF-related functional foods or food supplements.

Copy number profiling of circulating free DNA predicts transarterial chemoembolization response in advanced hepatocellular carcinoma.

Transarterial chemoembolization (TACE) is the most commonly used treatment for advanced hepatocellular carcinoma (HCC), but still lacks accurate real-time biomarkers for monitoring its therapeutic efficacy. Here, we explored whether copy number profiling of circulating free DNA (cfDNA) could be utilized to predict responses and prognosis in HCC patients with TACE treatment. In total, 266 plasma cfDNA samples were collected from 64 HCC patients, 57 liver cirrhosis (LC) patients and 32 healthy volunteers. We performed low-depth whole-genome sequencing (LD-WGS) on cfDNA samples to conduct copy number variant (CNV) analysis and tumour fraction (TFx) quantification. Then, the correlation between TFx/CNVs and therapeutic efficacy, treatment outcomes and lipiodol deposition were explored. The change in TFx during TACE treatment was associated with patients' tumour burden, and could accurately and earlier predict treatment response and prognosis, providing an alternative strategy other than mRECIST. Meanwhile, the chromosomal 16q/NQO1 amplification indicated worse therapeutic response; in patients who underwent multiple TACE sessions, TFx change during their first TACE treatment reflected the long-term survival; additionally, the copy number amplification of chromosome 1q, 3p, 6p, 8q, 10p, 12q, 18p or 18q affected lipiodol deposition. Overall, we have provided a new liquid biopsy approach for future TACE management of HCC patients.

Multi-task motor imagery electroencephalogram classification based on adaptive time-frequency common spatial pattern combined with convolutional neural network / 生物医学工程学杂志

The effective classification of multi-task motor imagery electroencephalogram (EEG) is helpful to achieve accurate multi-dimensional human-computer interaction, and the high frequency domain specificity between subjects can improve the classification accuracy and robustness. Therefore, this paper proposed a multi-task EEG signal classification method based on adaptive time-frequency common spatial pattern (CSP) combined with convolutional neural network (CNN). The characteristics of subjects' personalized rhythm were extracted by adaptive spectrum awareness, and the spatial characteristics were calculated by using the one-versus-rest CSP, and then the composite time-domain characteristics were characterized to construct the spatial-temporal frequency multi-level fusion features. Finally, the CNN was used to perform high-precision and high-robust four-task classification. The algorithm in this paper was verified by the self-test dataset containing 10 subjects (33 ± 3 years old, inexperienced) and the dataset of the 4th 2018 Brain-Computer Interface Competition (BCI competition Ⅳ-2a). The average accuracy of the proposed algorithm for the four-task classification reached 93.96% and 84.04%, respectively. Compared with other advanced algorithms, the average classification accuracy of the proposed algorithm was significantly improved, and the accuracy range error between subjects was significantly reduced in the public dataset. The results show that the proposed algorithm has good performance in multi-task classification, and can effectively improve the classification accuracy and robustness.

Efficient Production of 2'-Fucosyllactose from l-Fucose via Self-Assembling Multienzyme Complexes in Engineered Escherichia coli.

2'-Fucosyllactose (2'-FL) has been widely used as a nutritional additive in infant formula due to its multifarious nutraceutical and pharmaceutical functions in neonate health. As such, it is essential to develop an efficient and extensive microbial fermentation platform to cater to the needs of the 2'-FL market. In this study, a spatial synthetic biology strategy was employed to promote 2'-FL biosynthesis in recombinant Escherichia coli. First, the salvage pathway for 2'-FL production from l-fucose and lactose was constructed by introducing a bifunctional enzyme l-fucokinase/GDP-l-fucose pyrophosphorylase (Fkp) derived from Bacteroides fragilis and an α-1,2-fucosyltransferase (FutC) derived from Helicobacter pylori into engineered E. coli BL21(DE3). Next, the endogenous genes involved in the degradation and shunting of the substrate and key intermediate were inactivated to improve the availability of precursors for 2'-FL biosynthesis. Moreover, to further improve the yield and titer of 2'-FL, a short peptide pair (RIAD-RIDD) was used to form self-assembling multienzyme complexes in vivo. The spatial localization of peptides and stoichiometry of enzyme assemblies were subsequently optimized to further improve 2'-FL production. Finally, cofactor regeneration was also considered to alleviate the potential cofactor deficiency and redox flux imbalance in the biocatalysis process. Fed-batch fermentation of the final WLS20 strain accumulated 30.5 g/L extracellular 2'-FL with the yield and productivity of 0.661 mol/mol fucose and 0.48 g/L/h, respectively. This research has demonstrated that the application of spatial synthetic biology and metabolic engineering strategies can dramatically enlarge the titer and yield of 2'-FL biosynthesis in engineered E. coli.

Multi-omics analysis of brain tissue metabolome and proteome reveals the protective effect of gross saponins of Tribulus terrestris L. fruit against ischemic stroke in rat.

ETHNOPHARMACOLOGICAL RELEVANCE: Gross Saponins of Tribulus terrestris L. Fruit (GSTTF) has been reported to have a protective effect against ischemic stroke, but the related mechanism is complex and still not fully investigated. AIM OF THE STUDY: The combination of metabolomics and proteomics approach was applied to reveal the mechanisms of GSTTF in treating ischemic stroke. MATERIALS AND METHODS: The metabolite and protein changes in brain tissue were analyzed by the LC-MS-based untargeted metabolomics method and tandem mass tags (TMT)-based quantitative proteomics technology. The multivariate statistical analysis and protein-protein interaction (PPI) analysis were conducted to screen out the biomarkers, and their related pathway was further investigated by the joint pathway analysis. RESULTS: A total of 110 metabolites and 359 differential proteins, which were mainly associated with complement and coagulation cascades, sphingolipid metabolism, glycerophospholipid metabolism, glutathione metabolism, and platelet activation, etc. were screened out from the rat brain tissue. The PPI network exhibited that the protein F2, Fga, Fgb, Fgg, Plg, and C3, which are greatly involved in the complement and coagulation cascades, have a relatively high connectivity degree, indicating their importance in the process of middle cerebral artery occlusion (MCAO). The GSTTF exerted a protective effect against MCAO via modulating multiple proteins on this pathway. Moreover, F2 played a key role during the protective process and worth to be further investigated due to it has been reported as one of the therapeutic targets of ischemic stroke. CONCLUSION: The present study could improve the understanding of the potential therapeutic mechanism of GSTTF against ischemic stroke.

Identification of two UDP-glycosyltransferases involved in the main oleanane-type ginsenosides in Panax japonicus var. major.

MAIN CONCLUSION: Two UDP-glycosyltransferases from Panax japonicus var. major were identified, and the biosynthetic pathways of three oleanane-type ginsenosides (chikusetsusaponin IVa, ginsenoside Ro, zingibroside R1) were elucidated. Chikusetsusaponin IVa and ginsenoside Ro are primary active components formed by stepwise glycosylation of oleanolic acid in five medicinal plants of the genus Panax. However, the key UDP-glycosyltransferases (UGTs) in the biosynthetic pathway of chikusetsusaponin IVa and ginsenoside Ro are still unclear. In this study, two UGTs (PjmUGT1 and PjmUGT2) from Panax japonicus var. major involved in the biosynthesis of chikusetsusaponin IVa and ginsenoside Ro were identified based on bioinformatics analysis, heterologous expression and enzyme assays. The results show that PjmUGT1 can transfer a glucose moiety to the C-28 carboxyl groups of oleanolic acid 3-O-ß-D-glucuronide and zingibroside R1 to form chikusetsusaponin IVa and ginsenoside Ro, respectively. Meanwhile, PjmUGT2 can transfer a glucose moiety to oleanolic acid 3-O-ß-D-glucuronide and chikusetsusaponin IVa to form zingibroside R1 and ginsenoside Ro. This work uncovered the biosynthetic mechanism of chikusetsusaponin IVa and ginsenoside Ro, providing the rational production of valuable saponins through synthetic biology strategy.

Consumption of miRNA-Mediated Insect-Resistant Transgenic Rice Pollen Does Not Harm Apis mellifera Adults.

RNAi-based insect-resistant genetically engineered (IRGE) crops represent a promising approach for pest management by suppressing gene expressions or translation. A developed microRNA-mediated IRGE rice line expressing endogenous Chilo suppressalis Csu-novel-260 shows significant resistance to target pests. The nontarget insect Apis mellifera is an important pollinator used as a surrogate species for the ecological risk assessment of IRGE plants. To simulate a worst-case scenario, the full-length C. suppressalis and A. mellifera disembodied (dib) cDNAs were cloned. The dib 3'-untranslated regions shared 58.06% nucleotide sequence similarity between C. suppressalis and A. mellifera. No potential Csu-novel-260 binding site in Amdib was detected through the bioinformatics analysis. A dietary RNAi toxicity assay of the impacts of ingested Csu-novel-260 on A. mellifera adults showed that the survival rates of RNAi-treated A. mellifera did not significantly differ from those in the blank control (CK) and negative control (NC) treatments. The Csu-novel-260 uptake by A. mellifera peaked at 8 days postfeeding and then gradually decreased. The Amdib expression was not affected by the RNAi assay days or treatments. These results suggest that A. mellifera adults are not susceptible to high doses of Csu-novel-260 in the dietary RNAi assay and that the impact of miRNA-mediated IRGE plants on A. mellifera is negligible.

High quality genome of Erigeron breviscapus provides a reference for herbal plants in Asteraceae.

Erigeron breviscapus is an important medicinal plant in Compositae and the first species to realize the whole process from the decoding of the draft genome sequence to scutellarin biosynthesis in yeast. However, the previous low-quality genome assembly has hindered the optimization of candidate genes involved in scutellarin synthesis and the development of molecular-assisted breeding based on the genome. Here, the E. breviscapus genome was updated using PacBio RSII sequencing data and Hi-C data, and increased in size from 1.2 Gb to 1.43 Gb, with a scaffold N50 of 156.82 Mb and contig N50 of 140.95 kb, and a total of 43,514 protein-coding genes were obtained and oriented onto nine pseudo-chromosomes, thus becoming the third plant species assembled to chromosome level after sunflower and lettuce in Compositae. Fourteen genes with evidence for positive selection were identified and found to be related to leaf morphology, flowering and secondary metabolism. The number of genes in some gene families involved in flavonoid biosynthesis in E. breviscapus have been significantly expanded. In particular, additional candidate genes involved in scutellarin biosynthesis, such as flavonoid-7-O-glucuronosyltransferase genes (F7GATs) were identified using updated genome. In addition, three candidate genes encoding indole-3-pyruvate monooxygenase YUCCA2 (YUC2), serine carboxypeptidase-like 18 (SCPL18), and F-box protein (FBP), respectively, were identified to be probably related to leaf development and flowering by resequencing 99 individuals. These results provided a substantial genetic basis for improving agronomic and quality traits of E. breviscapus, and provided a platform for improving other draft genome assemblies to chromosome-level.

Fatty acid sensing GPCR (GPR84) signaling safeguards cartilage homeostasis and protects against osteoarthritis.

It is well known that free fatty acids (FFAs) have beneficial effects on the skeletal system, however, which fatty acid sensing GPCR(s) and how the GPCR(s) regulating cartilage development and osteoarthritis (OA) pathogenesis is largely unknown. In this study, we found Gpr84, a receptor for medium-chain FFAs (MCFA), was the only FFA-sensing GPCR in human and mouse chondrocytes that exhibited elevated expression when stimulated by interleukin (IL)-1ß. Gpr84-deficiency upregulated cartilage catabolic regulator expression and downregulated anabolic factor expression in the IL-1ß-induced cell model and the destabilization of the medial meniscus (DMM)-induced OA mouse model. Gpr84-/- mice exhibited an aggravated OA phenotype characterized by severe cartilage degradation, osteophyte formation and subchondral bone sclerosis. Moreover, activating Gpr84 directly enhanced cartilage extracellular matrix (ECM) generation while knockout of Gpr84 suppressed ECM-related gene expression. Especially, the agonists of GPR84 protected human OA cartilage explants against degeneration by inducing cartilage anabolic factor expression. At the molecular level, GPR84 activation inhibited IL-1ß-induced NF-κB signaling pathway. Furthermore, deletion of Gpr84 had little effect on articular and spine cartilaginous tissues during skeletal growth. Together, all of our results demonstrated that fatty acid sensing GPCR (Gpr84) signaling played a critical role in OA pathogenesis, and activation of GPR84 or MCFA supplementation has potential in preventing the pathogenesis and progression of OA without severe cartilaginous side effect.

Erythrocyte Membrane Polyunsaturated Fatty Acids Are Associated with Incidence of Metabolic Syndrome in Middle-Aged and Elderly People-An 8.8-Year Prospective Study.

BACKGROUND: The total and specific types of polyunsaturated fatty acids (PUFAs) related to metabolic syndrome (MetS) remain inconsistent. OBJECTIVE: We assessed the association of erythrocyte n-3 and n-6 PUFAs with MetS and the components of MetS in a cohort population. METHODS: This prospective analysis included 2754 participants (aged 40-75 y) from the Guangzhou Nutrition and Health Study (2008-2019) in China. Erythrocyte PUFAs at baseline were measured using gas chromatography. MetS was assessed every 3 y according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria. Multivariable Cox proportional hazard models were used to evaluate HRs and 95% CIs. RESULTS: We identified 716 incident cases of MetS. The primary analyses showed that the HRs (95% CIs) of MetS (tertile 3 versus 1) were 0.67 (0.56, 0.80) for n-3 PUFAs and 0.70 (0.58, 0.85) for n-6 PUFAs (all Ps trend <0.001). The secondary outcomes showed that, higher erythrocyte very-long-chain (VLC) PUFAs [20:3n-3, docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), arachidonic acid (ARA), and 22:4n-6], but lower α-linolenic acid (ALA) and γ-linolenic acid (GLA), tended to be associated with lower incidences of MetS and its components; among individual MetS components, the associations of PUFAs were more pronounced for hypertriglyceridemia (HTG) and hypertension, followed by low high-density lipoproten (HDL) cholesterol. Significantly higher concentrations of n-3 PUFAs (total, DPA, and DHA) and n-6 PUFAs (total, ARA, and 22:4) were observed in participants with improved (versus progressed) status of MetS (all Ps trend ≤0.003). CONCLUSION: This study reveals that higher erythrocyte VLC n-3 and n-6 PUFAs, but lower 18-carbon PUFAs (ALA and GLA), are associated with lower risks of MetS components (HTG, hypertension, and low HDL cholesterol) and thereby lower MetS incidence in Chinese adults.

Molecular Insight into Stereoselective ADME Characteristics of C20-24 Epimeric Epoxides of Protopanaxadiol by Docking Analysis.

Chirality is a common phenomenon, and it is meaningful to explore interactions between stereoselective bio-macromolecules and chiral small molecules with preclinical and clinical significance. Protopanaxadiol-type ginsenosides are main effective ingredients in ginseng and are prone to biotransformation into a pair of ocotillol C20-24 epoxide epimers, namely, (20S,24S)-epoxy-dammarane-3,12,25-triol (24S-PDQ) and (20S,24R)-epoxy dammarane-3,12,25-triol (24R-PDQ) that display stereoselective fate in vivo. However, possible molecular mechanisms involved are still unclear. The present study aimed to investigate stereoselective ADME (absorption, distribution, metabolism and excretion) characteristics of PDQ epimers based on molecular docking analysis of their interaction with some vital proteins responsible for drug disposal. Homology modeling was performed to obtain 3D-structure of the human isoenzyme UGT1A8, while calculation of docking score and binding free energy and ligand-protein interaction pattern analysis were achieved by using the Schrödinger package. Stereoselective interaction was found for both UGT1A8 and CYP3A4, demonstrating that 24S-PDQ was more susceptible to glucuronidation, whereas 24R-PDQ was more prone to oxidation catalyzed by CYP3A4. However, both epimers displayed similarly strong interaction with P-gp, a protein with energy-dependent drug-pump function, suggesting an effect of the dammarane skeleton but not C-24 stereo-configuration. These findings provide an insight into stereo-selectivity of ginsenosides, as well as a support the rational development of ginseng products.

Erythrocyte membrane n-3 polyunsaturated fatty acids are inversely associated with the presence and progression of nonalcoholic fatty liver disease in Chinese adults: a prospective study.

PURPOSE: Previous studies have shown that high-dose supplementation with n-3 polyunsaturated fatty acids (PUFAs) may benefit patients with nonalcoholic fatty liver disease (NAFLD), but the association of n-3 PUFAs with NAFLD among individuals with normal diets is only speculative. We investigated the cross-sectional and prospective associations between n-3 PUFAs and NAFLD in Chinese adults. METHODS: This community-based prospective study included 3049 men and women (40-75 years) in Guangzhou, China, whose participants completed an NAFLD ultrasound evaluation and erythrocyte PUFA tests. A total of 2660 participants underwent the second NAFLD evaluation approximately 3 years later. α-Linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes were measured by gas chromatography. RESULTS: After adjusting for potential confounders, we observed inverse associations between DHA, DHA + EPA, total n-3 PUFAs and the presence of NAFLD in the cross-sectional analysis. The adjusted odds ratios (95% confidence interval) of NAFLD for the highest (vs. lowest) tertile were 0.74 (0.61, 0.90) for DHA, 0.82 (0.67, 1.00) for EPA, 0.73 (0.60, 0.88) for DHA + EPA and 0.74 (0.61, 0.91) for total n-3 PUFAs  (all P values≤0.05). Over the average 3.12 years of follow-up, higher levels of DHA was associated with an improvement of NAFLD. The hazard ratio of improved NAFLD for the highest tertile was 1.18 (95% CI 1.09, 1.33) for DHA. Pathway analyses showed that favorable associations may be mediated by improvements in inflammatory markers (e.g., interleukin 1 beta and tumor necrosis factor alpha-like). CONCLUSIONS: Erythrocyte membrane n-3 PUFAs are inversely associated with the presence and progression of NAFLD in Chinese adults. TRIAL REGISTRATIONS: ClinicalTrials.gov NCT03179657.

In vitro and in silico evaluation of stereoselective effect of ginsenoside isomers on platelet P2Y12 receptor.

BACKGROUND: P2Y12 receptor (P2Y12R) is a newly discovered Gi-coupled ADP receptor that plays critical role in platelet function. Ginsenosides are the main constituents responsible for most of pharmacological actions of ginseng, especially cardio-cerebrovascular protective efficacy that is closely related to the influence on platelet function. HYPOTHESIS/PURPOSE: To explore stereoselective effect of naturally abundant ginsenoside isomers, including the C-20 epimers of protopanaxadiol (PPD), protopanaxatriol (PPT), and their glycosides Rg2, Rg3, Rh1, Rh2 on P2Y12R in platelets. STUDY DESIGN/METHODS: Both in vitro assay and in silico molecular docking study were performed to investigate the stereoselective effects. RESULTS: In vitro assay using washed rat platelets revealed differential effects of ginsenoside isomers on ADP-induced platelet aggregation with the direction and degree of action varying with chemical structures. More to the point, the ginsenoside 20S-Rh2 but not its 20R-epimer was found to be the only one that could significantly promote in vitro platelets aggregation induced by ADP. The correlation analysis demonstrated that ginsenosides may have impact on P2Y12R related platelet functions through a cAMP-dependent pathway. Molecular docking stimulation further indicated that ginsenoside isomers could be potent substrate of P2Y12R with differential protein-ligand interaction that would be responsible for the stereoselective efficacy of C-20 ginsenoside epimers. Hydrogen bonding with Asp266 via the C-20 hydroxyl may provide ginsenosides with promoting effect on ADP-induced platelets aggregation, whereas interactions with Tyr105 could contribute to the promotion of inhibitory efficacy. CONCLUSION: Ginsenosides are potent P2Y12R substrate with stereoselective effects on P2Y12R-related platelet function, which result from their chemical diversity and are closely related to the different interaction ways as P2Y12R ligand.

Pervasive Chromatin-RNA Binding Protein Interactions Enable RNA-Based Regulation of Transcription.

Increasing evidence suggests that transcriptional control and chromatin activities at large involve regulatory RNAs, which likely enlist specific RNA-binding proteins (RBPs). Although multiple RBPs have been implicated in transcription control, it has remained unclear how extensively RBPs directly act on chromatin. We embarked on a large-scale RBP ChIP-seq analysis, revealing widespread RBP presence in active chromatin regions in the human genome. Like transcription factors (TFs), RBPs also show strong preference for hotspots in the genome, particularly gene promoters, where their association is frequently linked to transcriptional output. Unsupervised clustering reveals extensive co-association between TFs and RBPs, as exemplified by YY1, a known RNA-dependent TF, and RBM25, an RBP involved in splicing regulation. Remarkably, RBM25 depletion attenuates all YY1-dependent activities, including chromatin binding, DNA looping, and transcription. We propose that various RBPs may enhance network interaction through harnessing regulatory RNAs to control transcription.

Discovery of potent indoleamine 2,3-dioxygenase (IDO) inhibitor from alkaloids in Picrasma quassioides by virtual screening and in vitro evaluation.

Indoleamine 2,3-dioxygenase (IDO) is one of the important targets for cancer immunotherapy through tryptophan pathway. Recently it has being paid great attention to search potent and safe IDO inhibitor from small-molecule compounds. Picrasma quassioides is a kind of medicinal plant abundant with tryptophan-derived indole alkaloids. By virtual screening and kinetic method for enzymatic analysis, lead compounds with potential IDO inhibitory activity were discovered for the first time from PQAs, the natural alkaloids in Picrasma quassioides. The results based on molecular docking analysis and structure-activity relationship (SAR) study demonstrated that coordinating with ferrous ion on the active site of IDO has a great impact on the inhibition potency, and ß-carboline with carboxyl substituted on C-1 is the key pharmacophore for IDO inhibition of PQAs. Enzymatic assay provided further evidence for the effectiveness of ß-carboline-1-carboxylic acid, which displayed as the most potent competitive inhibitor of IDO among these PQAs, and is even more potent than the recognized positive control 1-methyl tryptophan. This natural tryptophan-derived alkaloid thus deserved further deep research as a promising IDO modulator for cancer immunotherapy.

Transcriptome analysis of Panax zingiberensis identifies genes encoding oleanolic acid glucuronosyltransferase involved in the biosynthesis of oleanane-type ginsenosides.

MAIN CONCLUSION: Oleanolic acid glucuronosyltransferase (OAGT) genes synthesizing the direct precursor of oleanane-type ginsenosides were discovered. The four recombinant proteins of OAGT were able to transfer glucuronic acid at C-3 of oleanolic acid that yields oleanolic acid 3-O-ß-glucuronide. Ginsenosides are the primary active components in the genus Panax, and great efforts have been made to elucidate the mechanisms underlying dammarane-type ginsenoside biosynthesis. However, there is limited information on oleanane-type ginsenosides. Here, high-performance liquid chromatography analysis demonstrated that oleanane-type ginsenosides (particularly ginsenoside Ro and chikusetsusaponin IV and IVa) are the abundant ginsenosides in Panax zingiberensis, an extremely endangered Panax species in southwest China. These ginsenosides are derived from oleanolic acid 3-O-ß-glucuronide, which may be formed from oleanolic acid catalyzed by an unknown oleanolic acid glucuronosyltransferase (OAGT). Transcriptomic analysis of leaves, stems, main roots, and fibrous roots of P. zingiberensis was performed, and a total of 46,098 unigenes were obtained, including all the identified homologous genes involved in ginsenoside biosynthesis. The most upstream genes were highly expressed in the leaves, and the UDP-glucosyltransferase genes were highly expressed in the roots. This finding indicated that the precursors of ginsenosides are mainly synthesized in the leaves and transported to different parts for the formation of particular ginsenosides. For the first time, enzyme activity assay characterized four genes (three from P. zingiberensis and one from P. japonicus var. major, another Panax species with oleanane-type ginsenosides) encoding OAGT, which particularly transfer glucuronic acid at C-3 of oleanolic acid to form oleanolic acid 3-O-ß-glucuronide. Taken together, our study provides valuable genetic information for P. zingiberensis and the genes responsible for synthesizing the direct precursor of oleanane-type ginsenosides.