Induction of Thioredoxin Reductase 1 by Korean Red Ginseng Water Extract Regulates Cytoprotective Effects on Human Endothelial Cells

TXNRD1 knockdown inhibits the proliferation of endothelial cells subjected to oscillatory shear stress via activation of the endothelial nitric oxide synthase/apoptosis pathway

Atherosclerosis is the main cause of cardiovascular disease, and fluid shear stress is a key factor regulating its occurrence and development. Oscillatory shear stress (Oss) is an important pro-atherosclerosis factor. Oss mainly occurs in areas that are susceptible to atherosclerosis, but the exact mechanism of atherosclerosis induction remains unclear. Therefore, starting from the atheroprone phenotype that Oss stimulates abnormal vascular endothelial cell proliferation, this study aimed to reveal the underlying mechanism of Oss-induced atherosclerosis formation and to identify new targets for the prevention and treatment of atherosclerosis. In this study, the gene encoding thioredoxin reductase 1 (TXNRD1), which is closely related to atherosclerosis development and cell proliferation, was screened by analyzing the transcriptome sequencing data of static and Oss-treated human aortic endothelial cells (HAECs). Moreover, this study successfully verified that TXNRD1 mRNA and protein were significantly upregulated in Oss-treated HAECs. Oss significantly promoted the proliferation, migration, and tube formation of HAECs, whereas TXNRD1 knockdown impaired the proliferation, migration, and tube formation of Oss-treated HAECs, and this process was mainly achieved via activation of the apoptosis pathway. To further clarify whether Oss-sensitive TXNRD1 affects the apoptosis rate and proliferative ability of HAECs by regulating the endothelial nitric oxide synthase (eNOS) pathway, we used NG-nitro-L-arginine methyl ester (L-NAME) to inhibit eNOS activity and nitric oxide (NO) production. L-NAME significantly reversed the promoting effect of TXNRD1 knockdown on Oss-treated HAEC apoptosis, and it also abolished the inhibitory effect of TXNRD1 knockdown on the proliferation and S + G2 phase cell mass of Oss-treated HAECs. In conclusion, this study showed that TXNRD1 knockdown inhibited the proliferation of HAECs exposed to Oss by activating the eNOS/apoptosis pathway, revealing that TXNRD1 is involved in the dysregulation of Oss-induced endothelial cell proliferation. These findings provide new directions and insights into the prevention and treatment of atherosclerosis.

miR‑875‑5p regulates IR and inflammation via targeting TXNRD1 in gestational diabetes rats

Gestational diabetes mellitus (GDM) is a serious life‑threatening disease that affects the mother and fetus. However, the pathogenesis of GDM is still unclear. microRNAs (miRs) play vital roles in the regulation of various cell functions. The present study aimed to investigate the effects of miR‑875‑5p and thioredoxin reductase 1 cytoplasmic (TXNRD1) in GDM rats and analyze the associated underlying mechanism. A GDM rat model was induced using an intraperitoneal injection of streptozotocin. miR‑875‑5p knockdown plasmids or TXNRD1 knockdown plasmids were injected into the rats via the caudal vein. miR‑875‑5p and TXNRD1 expression in the serum were detected using reverse transcription‑quantitative PCR (RT‑qPCR) or western blot (WB) analyses. The fasting blood‑glucose (FBG), fasting serum insulin, triglyceride and high density lipoprotein levels were detected by specific commercial kits. The inflammatory response and the induction of oxidative stress were analyzed by assessing the expression of associated markers via WB, RT‑qPCR or commercial kits. The pancreatic and placental injuries were detected by hematoxylin and eosin staining. The results indicated that miR‑875‑5p expression levels were downregulated, whereas TXNRD1 levels were upregulated in GDM rats compared with normal pregnancy rats. miR‑875‑5p significantly regulated TXNRD1 expression in GDM rats. miR‑875‑5p silencing notably reduced FBG and insulin resistance, which was accompanied by reduced expression levels of blood lipid and pro‑inflammatory markers as well as reduced oxidative stress. However, the effects of miR‑875‑5p could be reversed by TXNRD1 silencing. Therefore, the present study indicated that miR‑875‑5p regulated IR and inflammation by targeting TXNRD1 in GDM rats. miR‑875‑5p and TXNRD1 may be considered as potential targets for treating GDM.

Chemical components of ginseng, their biotransformation products and their potential as treatment of hypertension

Ginseng is an ancient perennial herb belonging to the family Araliaceae and genus Panax which has been used for medical therapeutics for thousands of years, particularly in China and other Asian cultures although increasing interest in ginseng has recently emerged in western societies. Ginseng is a complex substance containing dozens of bioactive and potentially effective therapeutic compounds. Among the most studied are the ginsenosides, which are triterpene saponins possessing a wide array of potential therapeutic effects for many conditions. The quantity and type of ginsenoside vary greatly depending on ginseng species and their relative quantity in a given ginseng species is greatly affected by extraction processes as well as by subjecting ginseng to various procedures such as heating. Adding to the complexity of ginsenosides is their ability to undergo biotransformation to bioactive metabolites such as compound K by enteric bacteria following ingestion. Many ginsenosides exert vasodilatating effects making them potential candidates for the treatment of hypertension. Their vascular effects are likely dependent on eNOS activation resulting in the increased production of NO. One proposed end-mechanism involves the activation of calcium-activated potassium channels in vascular smooth cells resulting in reduced calcium influx and a vasodilatating effect, although other mechanisms have been proposed as discussed in this review.

Ameliorative effect of black ginseng extract against oxidative stress-induced cellular damages in mouse hepatocytes

Background

Oxidative stress induces the production of reactive oxygen species (ROS), which play important causative roles in various pathological conditions. Black ginseng (BG), a type of steam-processed ginseng, has drawn significant attention due to its biological activity, and is more potent than white ginseng (WG) or red ginseng (RG).

Methods

We evaluated the protective effects of BG extract (BGE) against oxidative stress-induced cellular damage, in comparison with WG extract (WGE) and RG extract (RGE) in a cell culture model. Ethanolic extracts of WG, RG, and BG were used to evaluate ginsenoside profiles, total polyphenols, flavonoid contents, and antioxidant activity. Using AML-12 cells treated with H₂O₂, the protective effects of WGE, RGE, and BGE on cellular redox status, DNA, protein, lipid damage, and apoptosis levels were investigated.

Results

BGE exhibited significantly enhanced antioxidant potential, as well as total flavonoid and polyphenol contents. ATP levels were significantly higher in BGE-treated cells than in control; ROS generation and glutathione disulfide levels were lower but glutathione (GSH) and NADPH levels were higher in BGE-treated cells than in other groups. Pretreatment with BGE inhibited apoptosis and therefore protected cells from oxidative stress-induced cellular damage, probably through ROS scavenging.

Conclusion

Collectively, our results demonstrate that BGE protects AML-12 cells from oxidative stress-induced cellular damages more effectively than WGE or RGE, through ROS scavenging, maintenance of redox status, and activation of the antioxidant defense system.

Implications of red Panax ginseng in oxidative stress associated chronic diseases

The steaming process of Panax ginseng has been reported to increase its major known bioactive components, ginsenosides, and, therefore, its biological properties as compared to regular Panax ginseng. Biological functions of red Panax ginseng attenuating pro-oxidant environments associated with chronic diseases are of particular interest, since oxidative stress can be a key contributor to the pathogenesis of chronic diseases. Additionally, proper utilization of various biomarkers for evaluating antioxidant activities in natural products, such as ginseng, can also be important to providing validity to their activities. Thus, studies on the effects of red ginseng against various diseases as determined in cell lines, animal models, and humans were reviewed, along with applied biomarkers for verifying such effects. Limitations and future considerations of studying red ginseng were been discussed. Although further clinical studies are warranted, red ginseng appears to be beneficial for attenuating disease-associated symptoms via its antioxidant activities, as well as for preventing oxidative stress-associated chronic diseases.