Au-Catalyzed Asymmetric Polyene Cyclization and Its Application in the Total Synthesis of (+)-2-Ketoferruginol, (+)-Fleuryinol B, (+)-Salviol, and (-)-Erythroxylisin A.

A catalytic asymmetric 1,3-acyloxy shift/polyene cyclization cascade has been achieved with good enantioselectivities under the catalysis of the chiral Au(I) reagent. The synthetic utility of this method has been showcased by the catalytic asymmetric total syntheses of (+)-2-ketoferruginol, (+)-fleuryinol B, and (+)-salviol. Notably, the first enantioselective total synthesis of (-)-erythroxylisin A has also been realized in 15 steps.

Calcium dobesilate attenuates renal ischemia-reperfusion injury in a mouse model.

BACKGROUND: Calcium dobesilate (CaD) is a microvascular protective agent that can significantly improve kidney function by reducing urinary protein, serum creatinine, and urea nitrogen levels. The effects of CaD on ischemia-reperfusion-induced acute kidney injury (AKI) were investigated in this study. METHOD: In this study, The Balb/c mice were randomly divided into (1) sham group, (2) I/R group, (3) I/R group + CaD (50 mg/kg) and (4) I/R group + CaD (500 mg/kg). After treatment, serum creatinine and urea nitrogen were detected. The levels of superoxide dismutase (SOD) and malonaldehyde (MDA) were examined. Then, the effects of CaD H2O2-damaged HK-2 cells were investigated, as reflected by the results of cell viability, reactive oxygen species (ROS) level, apoptosis and markers of kidney injury. RESULTS: The results showed that CaD treatment effectively attenuated the renal functions, pathological changes, and oxidative stress in I/R-induced AKI mice. It effectively reduced ROS production and improved MMP and apoptosis in H2O2-damaged HK-2 cells. The increased expression of apoptosis-related proteins and kidney injury biomarkers were significantly ameliorated after CaD treatment. CONCLUSION: Overall, CaD effectively ameliorated renal injury by eliminating ROS and demonstrated in vivo and in vitro for I/R-induced AKI. CaD has been shown to be a promising therapeutic agent for the treatment of I/R-induced AKI.

Mechanisms of Cynarine for treatment of non-alcoholic fatty liver disease based on the integration of network pharmacology, molecular docking and cell experiment.

BACKGROUND: Nonalcoholic Fatty Liver Disease (NAFLD) is a chronic Liver Disease prevalent all over the world. It has become more and more common in Japan, China and most western developed countries. The global prevalence rate is 25.24%, and the trend is increasing year by year. Related studies have shown that Cynarine has certain liver protection, lipid lowering and immune intervention effects. So, this study to systematically predict and analyze the mechanism of Cynarine in the treatment of non-alcoholic fatty liver disease (NAFLD) based on the integration of network pharmacology, molecular docking, and cell experiment. METHODS: We performed Heatmap and Venn diagram analyses to identify genes and targets in Cynarine treat NAFLD. The network of Cynarine-therapeutic targets and the protein-protein interaction network (PPI) was constructed. We used gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to visualize associated functional pathways. The Sybyl tool was used to dock the Cynarine with key therapeutic targets molecularly. Finally, cell experiments were applied to validate the role of Cynarine in the treatment of NAFLD. RESULTS: The Cynarine could act on 48 targets of NAFLD, and the role of CASP3, TP53, MMP9, ELANE, NOTCH1 were more important. The PPI network showed that immune and inflammation-related targets played a pivotal role. The KEGG analysis found that the PI3K-Akt signaling pathway, cell cycle and MAPK signaling pathway may be the main pathways for Cynarine to prevent and treat NAFLD. Molecular docking studies confirmed that Cynarine has good binding activity with therapeutic targets. Cynarine reduced the fat deposition ability of NAFLD model cells, and effectively reduced the levels of ALT and AST released by liver cells due to excessive lipid accumulation. We also found that Cynarine inhibited the expression of AKT1 and MAPK1. CONCLUSIONS: This study revealed that Cynarine could significantly reduce the fat deposition ability of NAFLD model cells, which may be closely related to the effective regulation of AKT1 and MAPK1 expression by Cynarine.

Transcriptome analysis of mouse male germline stem cells reveals characteristics of mature spermatogonial stem cells.

Spermatogonial stem cells (SSCs) are adult stem cells in the testis of male animals and have the ability in self-renewal and differentiation. SSCs are derived from primordial germ cells (PGCs) that are mitotically arrested in the embryo before birth. Following the birth of the animal, PGCs resume mitosis and migrate from the centre of the seminiferous tubules to the basement membrane. The descendent of PGCs (also called gonocytes) establish stable SSC colonies in about a week postnatally in order to support the life-long spermatogenesis. Whether SSCs at different developmental stages differ in their molecular and cellular characteristics is currently unclear. In the presented study, we conducted bioinformatics analyses using transcriptomics data established previously in the laboratory on OCT4 (encoded by the pluripotent gene Pou5f1) expressing SSCs from the neonatal (3 days-post-partum, 3-dpp), juvenile (7-dpp) and adult (2~3-month) mice, including screen of differentially expressed genes (DEGs), protein-protein interaction (PPI) network analysis of DEGs and clustering of sub-networks from PPI. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses were also performed on clustered sub-networks of the PPI. In addition, all genes were analyzed using GSEA (gene set enrichment analysis) based on GO, KEGG and HALLMARK gene sets. The results showed that SSCs have a large number of DEGs among OCT4-positive SSCs from neonatal, juvenile and adult mice. The distinguishable biological functions encoded by these DEGs include biosynthesis and energy metabolism, immune response, cell junction and expression of migration and cell differentiation-related genes. Significant changes in the cell membrane composition of OCT4-positive SSCs may not only cause hypersensitive immune reactions but also affect the cell-cell contact and responses to secreted cytokines in the extracellular environment. The results also suggest that OCT4-positive SSCs may shift metabolic state from oxidative phosphorylation to glycolysis and significantly reduce the transcription of genes related to ribosome formation during aging. These results provide new clues for future research on the regulatory mechanisms of male germline stem cell development, growth and aging.

Ginsenoside Rg5 Inhibits Succinate-Associated Lipolysis in Adipose Tissue and Prevents Muscle Insulin Resistance.

Endoplasmic reticulum (ER) stress, inflammation, and lipolysis occur simultaneously in adipose dysfunction and contribute to insulin resistance. This study was designed to investigate whether ginsenoside Rg5 could ameliorate adipose dysfunction and prevent muscle insulin resistance. Short-term high-fat diet (HFD) feeding induced hypoxia with ER stress in adipose tissue, leading to succinate accumulation due to the reversal of succinate dehydrogenase (SDH) activity. Rg5 treatment reduced cellular energy charge, suppressed ER stress and then prevented succinate accumulation in adipose tissue. Succinate promoted IL-1ß production through NLRP3 inflammasome activation and then increased cAMP accumulation by impairing PDE3B expression, leading to increased lipolysis. Ginsenoside Rg5 treatment suppressed NLRP3 inflammasome activation, preserved PDE3B expression and then reduced cAMP accumulation, contributing to inhibition of lipolysis. Adipose lipolysis increased FFAs trafficking from adipose tissue to muscle. Rg5 reduced diacylglycerol (DAG) and ceramides accumulation, inhibited protein kinase Cθ translocation, and prevented insulin resistance in muscle. In conclusion, succinate accumulation in hypoxic adipose tissue acts as a metabolic signaling to link ER stress, inflammation and cAMP/PKA activation, contributing to lipolysis and insulin resistance. These findings establish a previously unrecognized role of ginsenosides in the regulation of lipid and glucose homeostasis and suggest that adipose succinate-associated NLRP3 inflammasome activation might be targeted therapeutically to prevent lipolysis and insulin resistance.

Ginsenoside Rg5 attenuates hepatic glucagon response via suppression of succinate-associated HIF-1α induction in HFD-fed mice.

AIMS/HYPOTHESIS: Ginsenosides regulate glucose homeostasis. This study investigated the effect of ginsenoside Rg5 (Rg5) on the hepatic glucagon response, focusing on the regulation of metabolism. METHODS: Mice fed a high-fat diet (HFD) showed increased hepatic glucose production (HGP). We observed the effects of Rg5 on hepatic fatty acid oxidation and glucagon response. The regulation of phosphodiesterase (PDE) 4B by succinate was also investigated in hepatocytes. RESULTS: Rg5 inhibited endogenous glucose production in HFD-fed mice. Rg5 reduced cyclic AMP (cAMP) accumulation and inhibited transcriptional regulation of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) by dephosphorylation of the cAMP response element-binding transcription factor in the liver, demonstrating the inhibitory effect on hepatic glucagon response. HFD feeding increased succinate accumulation in the liver due to the reversal of succinate dehydrogenase activation and triggered hypoxia-inducible factor-1α (HIF-1α) induction. Succinate prevented cAMP degradation by inactivating PDE4B, thereby increasing cAMP accumulation in response to glucagon. Knockdown of HIF-1α with small interfering RNA diminished the effect of succinate, indicating that HIF-1α was essential for succinate to inactivate PDE4B. Rg5 inhibited succinate accumulation in hepatocytes by combating fatty acid oxidation, and thus reduced cAMP accumulation by blocking succinate/HIF-1α induction. Rg5 reduced HGP as a consequence of the inhibition of the glucagon response. CONCLUSIONS/INTERPRETATION: Succinate acted as a metabolic signal to enhance the hepatic glucagon response. Rg5 reduced hepatic succinate accumulation by combating fatty acid oxidation and attenuated the hepatic glucagon response by suppressing succinate/HIF-1α induction, suggesting that succinate-associated HIF-1α induction in hepatocytes might be a therapeutic target in the treatment of diabetes.

Differential regulation of baicalin and scutellarin on AMPK and Akt in promoting adipose cell glucose disposal.

Baicalin and scutellarin, two flavonoid glucuronic acids isolated from Scutellaria baicalensis, exhibit beneficial effects on glucose homeostasis. Baicalin and scutellarin are similar in structure except scutellarin has an additional hydroxyl at composition C-4'. In this work, we observed that baicalin and scutellarin promoted glucose disposal in mice and in adipocytes. Baicalin selectively increased phosphorylation of AMP-activated kinase (AMPK), while scutellarin selectively enhanced Akt phosphorylation. Both of them increased AS160 phosphorylation and glucose uptake in basal condition. AMPK inhibitor or knockdown of AMPK by siRNA blocked baicalin-induced AS160 phosphorylation and glucose uptake, but showed no effects on scutellarin. In contrast, Akt inhibitor and knockdown of Akt with siRNA decreased scutellarin-stimulated glucose uptake but had no effects on baicalin. The molecular dynamic simulations analysis showed that the binding energy of baicalin to AMPK (-34.30kcal/mol) was more favorable than scutellarin (-21.27kcal/mol), while the binding energy of scutellarin (-29.81kcal/mol) to Akt was much more favorable than baicalin (4.04kcal/mol). Interestingly, a combined treatment with baicalin and scutellarin acted synergistically to enhance glucose uptake in adipocytes (combination index: 0.94-0.046). In conclusion, baicalin and scutellarin, though structurally similar, promoted glucose disposal in adipocytes by differential regulation on AMPK and Akt activity. Our data provide insight that multicomponent herbal medicines may act synergistically on multiple targets.

Pharmacokinetic comparison between quercetin and quercetin 3-O-ß-glucuronide in rats by UHPLC-MS/MS.

Quercetin is a natural flavonoid widely distributed in human diet and functional foods. Quercetin 3-O-ß-glucuronide (Q3G) is present in wine and some medicinal plants. Quercetin and Q3G may be metabolized from each other in vivo. While quercetin has been the subject of many studies, the pharmacokinetic profiles of quercetin and Q3G (in animals) have not yet been compared. Herein, we prepared a column-based method for rapid isolation of Q3G from Nelumbo nucifera. Then, we developed an UHPLC-MS/MS method to compare the pharmacokinetics of quercetin and Q3G. Our results showed that the plasma concentration-time curves of quercetin and Q3G show two maxima (Tmax1 ≈ 0.75 h, Tmax2 ≈ 5 h). After oral administration of 100 mg/kg quercetin or 100 mg/kg Q3G in rats, predominantly Q3G was detected in plasma with AUC at 39529.2 ± 6108.2 mg·h·L-1 or 24625.1 ± 1563.8 mg·h·L-1, 18-fold higher than quercetin with AUC at 1583.9 ± 583.3 mg·h·L-1 or 1394.6 ± 868.1 mg·h·L-1, respectively. After intravenous injection of 10 mg/kg in rats, Q3G showed extensive tissue uptake in kidney (409.2 ± 118.4 ng/g), liver (166.1 ± 52.9 ng/g), heart (97.7 ± 22.6 ng/g), and brain (5.8 ± 1.2 ng/g). In conclusion, we have shown that Q3G is a major active component in plasma and tissue for oral administration of quercetin or Q3G.

[Effect of TGF-ß1 expression on periodontal tissue reconstruction for rapid teeth movement through reducing resistance and distraction].

PURPOSE: To investigate the role of transforming growth factor-ß1 (TGF-ß1) in periodontal tissue reconstruction during rapid teeth movement through reducing resistance and distraction. METHODS: Twenty Beagle dogs were randomly divided into five groups according to time points: distraction for 5 days, 10 days, 15 days, retaining 10 days after distraction for 15 days, and retaining 90 days after distraction for 15 days. The mandibular first premolar was moved by using reducing resistance and distraction (experimental group) or conventional distraction (control group) randomly. For each group, tooth movement distance was measured and first premolar periodontal tissue pieces were obtained in scheduled time. Hematoxylin-eosin stain, Picric acid-Sirius red, and immunohistochemistry were performed. The data was analyzed by using SPSS 18.0 software package. RESULTS: The speed of tooth movement and periodontal reconstruction of the experimental group were significantly faster than the control group. TGF-ß1 positive expression in two groups had similar distribution area, and reached peak at most active stage of osteogenesis in both groups. But in different stages of distraction, the positive expression in the experimental group was significantly higher than the control group(P<0.05). CONCLUSIONS: Compared with conventional orthodontic method, reducing resistance and distraction can obviously increase the expression of TGF-ß1 of tension side of the distracted tooth, and accelerate periodontal tissue reconstruction.

A polypyridyl-pyrene based off-on Cd²âº fluorescent sensor for aqueous phase analysis and living cell imaging.

By retaining the quadrapyridyl receptor of polypyridylhexaazatriphenylene (a Cd(2+) sensor reported by us) and extending its chromophoric group with pyrene, a chemical sensor (1) was designed and synthesized in this work. This sensor exhibit selective off-on fluorescence response to Cd(2+) over other metal ions, and the detection limit is as low as 0.02 µM. The Cd(2+) sensing of 1 has high water toleration and can be carried out in the media with the water content up to 70%. Additionally, 1 was successfully applied to the in vivo imaging of intracellular Cd(2+) in living HaLa cells, and showed low cytotoxicity and cell membrane permeability in these experiments. These results suggest that 1 has potential application in the Cd(2+) analysis of environmental and biological samples.

A luminescent 2D coordination polymer for selective sensing of nitrobenzene.

A luminescent two-dimensional (2D) coordination polymer is demonstrated to be a selective sensing material for the straightforward detection of nitrobenzene via a redox fluorescence quenching mechanism.