Ginsenoside Rg3 overcomes tamoxifen resistance through inhibiting glycolysis in breast cancer cells

Tamoxifen (TAM) resistance poses a significant clinical challenge in human breast cancer and exhibits high heterogeneity among different patients. Rg3, an original ginsenoside known to inhibit tumor growth, has shown potential for enhancing TAM sensitivity in breast cancer cells. However, the specific role and underlying mechanisms of Rg3 in this context remain unclear. Aerobic glycolysis, a metabolic process, has been implicated in chemotherapeutic resistance. In this study, we demonstrate that elevated glycolysis plays a central role in TAM resistance and can be effectively targeted and overcome by Rg3. Mechanistically, we observed upregulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a key mediator of glycolysis, in TAM-resistant MCF-7/TamR and T-47D/TamR cells. Crucially, PFKFB3 is indispensable for the synergistic effect of TAM and Rg3 combination therapy, which suppresses cell proliferation and glycolysis in MCF-7/TamR and T-47D/TamR cells, both in vitro and in vivo. Moreover, overexpression of PFKFB3 in MCF-7 cells mimicked the TAM resistance phenotype. Importantly, combination treatment significantly reduced TAM-resistant MCF-7 cell proliferation in an in vivo model. In conclusion, this study highlights the contribution of Rg3 in enhancing the therapeutic efficacy of TAM in breast cancer, and suggests that targeting TAM-resistant PFKFB3 overexpression may represent a promising strategy to improve the response to combination therapy in breast cancer.

Ginsenoside Rg3 decreases breast cancer stem-like phenotypes through impairing MYC mRNA stability

Breast cancer stem cells (BCSCs) are responsible for breast cancer metastasis, recurrence and treatment resistance, all of which make BCSCs potential drivers of breast cancer aggression. Ginsenoside Rg3, a traditional Chinese herbal medicine, was reported to have multiple antitumor functions. Here, we revealed a novel effect of Rg3 on BCSCs. Rg3 inhibits breast cancer cell viability in a dose- and time-dependent manner. Importantly, Rg3 suppressed mammosphere formation, reduced the expression of stemness-related transcription factors, including c-Myc, Oct4, Sox2 and Lin28, and diminished ALDH(+) populations. Moreover, tumor-bearing mice treated with Rg3 exhibited robust delay of tumor growth and a decrease in tumor-initiating frequency. In addition, we found that Rg3 suppressed breast cancer stem-like properties mainly through inhibiting MYC expression. Mechanistically, Rg3 accelerated the degradation of MYC mRNA by enhancing the expression of the let-7 family, which was demonstrated to bind to the MYC 3' untranslated region (UTR). In conclusion, our findings reveal the remarkable suppressive effect of Rg3 on BCSCs, suggesting that Rg3 is a promising therapeutic treatment for breast cancer.

Phytochemistry of Red Ginseng, a Steam-Processed Panax ginseng

Asian ginseng, the root of Panax ginseng C.A. Meyer, occupies a prominent position in the list of best-selling natural products in the world. There are two major types of ginseng roots: white ginseng and red ginseng, each with numerous preparations. White ginseng is prepared by air-drying fresh Asian ginseng roots after harvest. Red ginseng is prepared by steaming roots in controlled conditions using fresh or raw Asian ginseng. Red ginseng is commonly used in Asian countries due to its unique chemical profile, different therapeutic efficacy, and increased stability. Compared with the widespread research on white ginseng, the study of red ginseng is relatively limited. In this paper, after a botanical feature description, the structures of different types of constituents in red ginseng are systematically described, including naturally occurring compounds and those resulting from the steam processing. In red ginseng phytochemical studies, the number of published reports on ginsenosides is significantly higher than that for other constituents. Up to now, 57 ginsenosides have been isolated and characterized in red ginseng. The structural transformation pathways during steaming have been summarized. In comparison with white ginseng, red ginseng also contains other constituents, including polyacetylenes, Maillard reaction products, other types of glycosides, lignans, amino acids, fatty acids, and polysaccharides, which have also been presented. Appropriate analytical methods are necessary for differentiating between unprocessed white ginseng and processed red ginseng. Specific marker compounds and chemical profiles have been used to discriminate red ginseng from white ginseng and adulterated commercial products. Additionally, a brief phytochemical profile comparison has been made between white ginseng and black ginseng, and the latter is another type of processed ginseng prepared from white or red ginseng by steaming several times. In conclusion, to ensure the safe and effective use of red ginseng, phytochemical and analytical studies of its constituents are necessary and even crucial.

Alleviation of D-gal-induced senile liver injury by Rg3, a signature component of red ginseng

To investigate the mechanism by which ginsenoside Rg3 regulates oxidative stress (OS) and inflammation through NF/KB pathway to delay mouse liver injury. This work randomized Balbc mice as four groups: Normal, D-gal, Rg3-L, Rg3-H. Paraffin-embedded liver tissue sections were prepared, later, BAX/BCL-2 protein expression was observed by HE, Sirius red, TUNEL and immunofluorescence to detect apoptotic injury and α-SMA/TGF-β protein expression to detect fibrosis, and liver inflammation-related protein NF-KB was detected. HE and TUNEL staining showed that Rg3 reduced necrotic cells and fibrosis in liver-injured mice, Rg3 increased anti-inflammatory cytokine IL-18 and reduced TNF-α, IL-1β and IL-6 expression. Conclusion: Ginsenoside Rg3 can effectively antagonize D-gal's role in mouse liver injury, and its mechanism may be associated with regulating inflammatory pathway by Rg.

Preparation and bioactivity of the rare ginsenosides Rg3 and Rh2: An updated review

Ginseng, an ancient medicinal herb, is used in oriental medicine for the treatment of various diseases. Saponins are the main bioactive components of ginseng, but the multiple glucosyl side chains on its molecules prevent ginsenosides from entering the blood through the intestinal membrane, thus reducing the efficacy. The preparation of rare ginsenosides, which are easy to be absorbed by human body and have higher drug activity, has been widely practiced by removing the sugar group of natural ginsenosides in vitro. Rare ginsenosides Rg3 and Rh2 have been approved as drugs or health supplements to improve immune function. This review summarizes the preparation methods of ginsenoside Rg3 and Rh2 in recent years. Ginsenoside Rg3 and Rh2 were prepared by biotransformation of protopanaxadiol type ginsenoside, with the highest conversion rate of 98.19% and 95.89% in the laboratory, respectively. At present, improving the conversion rate and reducing the production cost are still the bottleneck of industrial scale production of Rg3 and Rh2 through the deglycosylation directly from Rb1, Rb2, Rb3, Rc and Rd in the crude extract of ginseng. In addition, ginsenosides Rg3 and Rh2 play anti-inflammatory, anticancer, cardiovascular protective, immunomodulatory, neuroprotective, anti-diabetic, anti-fatigue, anti-allergic, anti-aging, antioxidant and other pharmacological effects by activating AMPK, JNK, NF-κB, MAPKs, P13K/AKT/mTOR and other signaling pathways. As potential drugs for prevention and treatment of various diseases, ginsenoside Rg3 and Rh2 need to further clarify other underlying mechanisms of action through in vitro and in vivo experiments.

Rg3-enriched Korean red ginseng alleviates chloroquine-induced itch and dry skin pruritus in an MrgprA3-dependent manner in mice

Background

Previous studies have found that Korean red ginseng extract (KRG) has antipruritic effects, which can be attributed to the presence of Rg3, one of the most potent ginsenosides. Therefore, Rg3-enriched KRG extract (Rg3EKRG) is anticipated to have enhanced antipruritic effects. The present study was conducted to examine the effects of Rg3EKRG in acute chloroquine (CQ)-induced and chronic dry skin pruritus.

Methods

Calcium imaging technique was used in HE293T cells expressing MrgprA3 and TRPA1 ("MrgprA3/TRPA1") and in primary cultures of mouse dorsal root ganglia (DRG) neurons. Mouse scratching behavior tests were performed on dry skin models. To verify the altered expression of itch-related genes, real-time RNA sequencing analysis and PCR were performed on DRG sections obtained from dry skin models.

Results

Rg3EKRG suppressed CQ-induced intracellular calcium changes to a greater degree than KRG. Rg3EKRG dose-dependently inhibited CQ-induced responses in MrgprA3/TRPA1 cells. Rg3EKRG likely targeted MrgprA3 rather than TRPA1 to exert its inhibitory effect. Further, Rg3EKRG strongly inhibited the scratching behavior in mice induced by acute CQ injection. Importantly, DRG neurons obtained from dry skin mice models showed increased mRNA levels of MrgprA3, and treatment with Rg3EKRG alleviated chronic dry skin conditions and suppressed spontaneous scratching behaviors.

Conclusion

The results of the present study imply that Rg3EKRG has a stronger antipruritic effect than KRG, inhibiting both acute CQ-induced and chronic dry skin pruritus in an MrgprA3-dependent manner. Therefore, Rg3EKRG is a potential antipruritic agent that can suppress acute and chronic itching at the peripheral sensory neuronal level.

Ginsenoside Rg3 inhibits renal cell carcinoma cell migration, invasion, colony formation, and tube formation and enhances apoptosis through promoting the DNA demethylation and histone acetylation

OBJECTIVES

This study explored the effect and mechanism of Rg3 on renal cell carcinoma (RCC) progression.

METHODS

RCC cells were treated with different concentrations of Rg3, 5-Aza-dc (a methyltransferase inhibitor) or TSA (a deacetylase inhibitor). Rg3-induced cytotoxicity, migration, invasion, colony formation, tube formation and apoptosis of RCC cells were evaluated by CCK-8, wound healing, Transwell, colony formation, tube formation and flow cytometry assays, respectively. Methylation and expressions of p53, p21 and p16, and expressions of methylation-related genes and histone deacetylases and histone acetylation-related genes (H3 (acetyl K14), H3 (acetyl K9), H4 (acetyl K12), H4 (acetyl K5) and H4 (acetyl K16)) were analysed by qRT-PCR and western blot.

KEY FINDINGS

Rg3 dose-dependently decreased the viability, inhibited migration, invasion, colony formation and tube formation, and enhanced apoptosis of RCC cells. Rg3 enhanced the demethylation levels and expressions of p53, p21 and p16 as well as the expressions of histone acetylation-related genes, but repressed the expressions of methylation-related genes and histone deacetylases. Rg3 had the same effect as 5-Aza-dc and TSA did on the above-mentioned cellular changes.

CONCLUSION

Rg3 restrains RCC cell migration, invasion, colony formation and tube formation, yet enhances apoptosis through promoting demethylation of p53, p21 and p16, and histone acetylation.

Ginsenoside Rg3 inhibits osteosarcoma progression by reducing circ_0003074 expression in a miR-516b-5p/KPNA4-dependent manner

Background

Previous data have suggested that ginsenoside Rg3 (Rg3), isolated from the roots of Panax ginseng, plays a repressing role in multiple cancers, including osteosarcoma (OS). However, there is no any literature available about the role of circular RNA (circRNA) in Rg3-mediated OS development. The study aimed to explore the function of circ_0003074 in the anti-cancer effects of Rg3 on OS.

Methods

RNA expression of circ_0003074, miR-516b-5p and karyopherin subunit alpha 4 (KPNA4) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was evaluated by Western blotting or immunohistochemistry assay. Cell viability, proliferation, apoptosis, migration and invasion were investigated by cell counting kit-8, 5-ethynyl-29-deoxyuridine (EdU), flow cytometry analysis, wound-healing and transwell invasion assays, respectively. Dual-luciferase reporter and/or RNA immunoprecipitation assay was performed to confirm the interplay between miR-516b-5p and circ_0003074 or KPNA4. Xenograft mouse model assay was conducted to reveal the effect of Rg3 treatment on tumor formation.

Results

Circ_0003074 and KPNA4 expression was significantly upregulated, while miR-516b-5p was downregulated in OS tissues and cells compared with controls. Rg3 treatment dramatically decreased circ_0003074 expression in OS cells. Rg3 treatment led to decreased cell proliferation, migration and invasion but increased cell apoptosis, which was attenuated after circ_0003074 overexpression. Besides, miR-516b-5p was a target miRNA of circ_0003074 and partially restored circ_0003074-mediated action under Rg3 treatment. Decreasing miR-516b-5p expression also promoted Rg3-treated OS cell malignancy through KPNA4, which was identified as a target mRNA of miR-516b-5p. Besides, circ_0003074 induced KPNA4 production owing to the decrease of miR-516b-5p expression. Furthermore, Rg3 treatment inhibited tumor formation by regulating circ_0003074 in vivo.

Conclusion

Rg3 inhibited OS progression through circ_0003074/miR-516b-5p/KPNA4 axis, showing the potential of Rg3 as a therapeutic agent for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02868-7.

Circ_0003074 expression was upregulated in OS tissues and cells.

Rg3 treatment significantly decreased circ_0003074 expression in OS cells.

Circ_0003074 overexpression rescued Rg3-induced inhibition in OS progression.

Circ_0003074 induced KPNA4 production through miR-516b-5p under Rg3 treatment.

Carbon nanotubes (CNT)-loaded ginsenosides Rb3 suppresses the PD-1/PD-L1 pathway in triple-negative breast cancer

Carbon nanotubes (CNTs), as advanced nanotechnology with specific properties and structures, have presented practical drug delivery properties. Ginsenoside Rg3 is a component of puffed ginseng and demonstrates anti-cancer activities. To explore the effect of CNTs-loaded Rg3 (Rg3-CNT) on the PD-1/PD-L1 signaling and the development of triple-negative breast cancer (TNBC). Our data revealed that Rg3 inhibited the cell viability of TNBC cells, in which Rg3-CNT further enhanced this effect in the system. Similarly, the colony formation of TNBC cells was decreased by Rg3, while Rg3-CNT could reinforce its effect in the cells. Besides, the treatment of Rg3 induced apoptosis of TNBC cells, in which Rg3-CNT treatment further increased the phenotype in the cells. Remarkably, Rg3-CNT, but not Rg3, attenuated PD-L1 expression in TNBC cells. Rg3-CNT decreased the PD-L1 upregulation induced by interferon-γ (IFN-γ) in breast cancer cells. Importantly, Rg3-CNT was able to reduce PD-1 expression in activated T cells. Specifically, Rg3-CNT reduced the PD-1/PD-L1 axis in a T cell/triple-negative TNBC cell co-culture system. Moreover, the levels of IFN-γ, interleukins-2 (IL-2), interleukins-9 (IL-9), interleukins-10 (IL-10), interleukins-22 (IL-22), and interleukins-23 (IL-23) were significantly stimulated in the activated T cells, while the treatment of Rg3-CNT could reverse these phenotypes in the cells. Rg3-CNT attenuated the TNBC cell growth in vivo. The Rg3-CNT improved the anti-cancer effect of Rg3 toward TNBC by inhibiting the PD-1/PD-L1 axis. Our finding provides new insights into the mechanism by which Rg3-CNT attenuates the development of TNBC. Rg3-CNT may be applied as the potential therapeutic strategy for immunotherapy of TNBC.

Fermented Ginseng Extract, BST204, Suppresses Tumorigenesis and Migration of Embryonic Carcinoma through Inhibition of Cancer Stem Cell Properties

The pharmacological effects of BST204—a fermented ginseng extract—on several types of cancers have been reported. However, the effects of ginseng products or single ginsenosides against cancer stem cells are still poorly understood. In this study, we identified the anti-tumorigenic and anti-invasive activities of BST204 through the suppression of the cancer stem cell marker, CD133. The treatment of embryonic carcinoma cells with BST204 induced the expression of the tumor suppressor protein, p53, which decreased the expression of cell cycle regulatory proteins and downregulated the expression of CD133 and several stemness transcription factors. These changes resulted in both the inhibition of tumor cell proliferation and tumorigenesis. The knockdown of CD133 suggests that it has a role in tumorigenesis, but not in cancer cell proliferation or cell cycle arrest. Treatment with BST204 resulted in the reduced expression of the mesenchymal marker, N-cadherin, and the increased expression of the epithelial marker, E-cadherin, leading to the suppression of tumor cell migration and invasion. The knockdown of CD133 also exhibited an anti-invasive effect, indicating the role of CD133 in tumor invasion. The single ginsenosides Rg3 and Rh2—major components of BST204—exhibited limited effects against cancer stem cells compared to BST204, suggesting possible synergism among several ginsenoside compounds.

Inhibition of Programmed Death Receptor-1/Programmed Death Ligand-1 Interactions by Ginsenoside Metabolites

Evidence suggests that programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) targeted inhibitors act as an immune checkpoint blockade, indicating that these compounds may be useful in cancer immunotherapy by inhibiting the immune response between T-cells and tumors. Previous studies have shown that ginsenosides can regulate the expression of PD-1 and PD-L1 in target diseases; however, it remains unknown whether ginsenosides act as a blockade of PD-1/PD-L1 interactions. In this study, we used competitive ELISA to investigate 12 ginsenosides for their ability to block PD-1/PD-L1 interactions. In addition, we performed a protein-ligand docking simulation and examined the hydrophobic interactions and hydrogen bonds formed at the interfaces between the ginsenosides and PD-L1/PD-1. Eight out of the 12 ginsenosides studied showed inhibition of PD-1/PD-L1 interactions at 35% at the maximum concentration (1 μM). Among them, Rg3 and Compound K (C-K) demonstrated the highest inhibitory effects. Rg3 and C-K were further identified for their interaction efficacy with PD-1/PD-L1, which supported our results demonstrating the blocking activity of these compounds against PD-1/PD-L1 binding interactions. Collectively, our findings suggest that some ginsenosides, including Rg3 and C-K, inhibit PD-1/PD-L1 binding interactions. Therefore, these compounds may prove useful as part of an overall immuno-oncological strategy.

Relationship Between Ginsenoside Rg3 and Metabolic Syndrome

Metabolic syndrome is an important public health issue and is associated with a more affluent lifestyle. Many studies of metabolic syndrome have been reported, but its pathogenesis remains unclear and there is no effective treatment. The ability of natural compounds to ameliorate metabolic syndrome is currently under investigation. Unlike synthetic chemicals, such natural products have proven utility in various fields. Recently, ginsenoside extracted from ginseng and ginseng root are representative examples. For example, ginseng is used in dietary supplements and cosmetics. In addition, various studies have reported the effects of ginsenoside on metabolic syndromes such as obesity, diabetes, and hypertension. In this review, we describe the potential of ginsenoside Rg3, a component of ginseng, in the treatment of metabolic syndrome.

Ginsenoside Rg3 Induces Browning of 3T3-L1 Adipocytes by Activating AMPK Signaling

Ginsenoside Rg3, one of the major components in Panax ginseng, has been reported to possess several therapeutic effects including anti-obesity properties. However, its effect on the browning of mature white adipocytes as well as the underlying mechanism remains poorly understood. In this study, we suggested a novel role of Rg3 in the browning of mature 3T3-L1 adipocytes by upregulating browning-related gene expression. The browning effects of Rg3 on differentiated 3T3-L1 adipocytes were evaluated by analyzing browning-related markers using quantitative PCR, immunoblotting, and immunostaining. In addition, the size and sum area of lipid droplets in differentiated 3T3-L1 adipocytes were measured using Oil-Red-O staining. In mature 3T3-L1 adipocytes, Rg3 dose-dependently induced the expression of browning-related genes such as Ucp1, Prdm16, Pgc1α, Cidea, and Dio2. Moreover, Rg3 induced the expression of beige fat-specific genes (CD137 and TMEM26) and lipid metabolism-associated genes (FASN, SREBP1, and MCAD), which indicated the activation of lipid metabolism by Rg3. We also demonstrated that activation of 5' adenosine monophosphate-activated protein kinase (AMPK) is required for Rg3-mediated up-regulation of browning gene expression. Moreover, Rg3 inhibited the accumulation of lipid droplets and reduced the droplet size in mature 3T3-L1 adipocytes. Taken together, this study identifies a novel role of Rg3 in browning of white adipocytes, as well as suggesting a potential mechanism of an anti-obesity effect of Panax ginseng.

A Critical Regulation of Th17 Cell Responses and Autoimmune Neuro-Inflammation by Ginsenoside Rg3

Among diverse helper T-cell subsets, Th17 cells appear to be pathogenic in diverse autoimmune diseases, and thus, targeting Th17 cells could be beneficial for the treatment of the diseases in humans. Ginsenoside Rg3 is one of the most potent components in Korean Red Ginseng (KRG; Panax ginseng Meyer) in ameliorating inflammatory responses. However, the role of Rg3 in Th17 cells and Th17-mediated autoimmunity is unclear. We found that Rg3 significantly inhibited the differentiation of Th17 cells from naïve precursors in a dendritic cell (DC)–T co-culture system. While Rg3 minimally affected the secretion of IL-6, TNFα, and IL-12p40 from DCs, it significantly hampered the expression of IL-17A and RORγt in T cells in a T-cell-intrinsic manner. Moreover, Rg3 alleviated the onset and severity of experimental autoimmune encephalomyelitis (EAE), induced by transferring myelin oligodendrocyte glycoprotein (MOG)-reactive T cells. Our findings demonstrate that Rg3 inhibited Th17 differentiation and Th17-mediated neuro-inflammation, suggesting Rg3 as a potential candidate for resolving Th17-related autoimmune diseases.

Intake consumption of ginsenoside Rg3, profiling of selected cytokines, and development of rectal polyps

Background: Rectal polyps is a major risk factor for rectal cancer. There is a need to explore a panel of preventive measures, as well as reliable biomarkers for screening of rectal polyps.

Patients and methods: We conducted a case control study which aimed to explore the effects of regular consumption of ginsenoside Rg3, profiling of selected cytokines, and development of rectal polyps in a Chinese population.

Results: Significantly higher levels of IL-4, MIP-1β, FasL, TGF-β1, and RANTES were detected in rectal polyp cases. Further, we found significant dose-response relationships between quartile-categorized levels of IL-4, MIP-1β, FasL, and TGF-β1, and risk of rectal polyps. The strongest associations for IL-4, MIP-1β, FasL, and TGF-β1 were observed for the highest quartile vs the lowest quartile with an OR of 1.78, 2.70, 1.49, and 2.36, respectively. Compared with non-Rg3 consumers, regular Rg3 consumers had a significantly lower risk of rectal polyps (OR =0.71; 95% CI: 0.55–0.92; P=0.009). We also found that Rg3 consumers had significantly lower levels of IL-4, MIP-1β, FasL, and TGF-β1 than non-Rg3 consumers, in both rectal polyp cases and healthy controls.

Conclusion: These results indicate that regular consumption of Rg3 might prevent the occurrence of rectal polyps through decreasing the serum level of selected cytokines, including IL-4, MIP-1β, FasL, and TGF-β1. Further clinical trials and prospective cohort studies with larger sample sizes are warranted to validate the anti-inflammatory activity and the anti-tumorigenic role of Rg3.

Downregulation of HDAC3 by ginsenoside Rg3 inhibits epithelial-mesenchymal transition of cutaneous squamous cell carcinoma through c-Jun acetylation

The metastatic rate of human cutaneous squamous cell carcinoma (CSCC) has increased in recent years. Despite the current advances in therapies, effective treatments remain lacking. Ginsenoside 20(R)-Rg3 is an effective antitumor monomer extracted from ginseng, but the role of Rg3 in CSCC remains unknown. It has been reported that aberrantly elevated histone deacetylase 3 (HDAC3) is involved in tumor malignancy in multiple malignant tumors. However, the effects of HDAC3 on the regulation of c-Jun acetylation in tumor epithelial-mesenchymal transition (EMT) and migration have not been clearly illuminated. In our research, the immunohistochemistry staining results of skin tissue microarrays showed that HDAC3 staining was increased in CSCC compared with the normal dermal tissue. Then, we found that Rg3 treatment (25 and 50 μg/ml) inhibited CSCC cell (A431 and SCC12 cells) EMT through increasing E-cadherin and decreasing N-cadherin, vimentin, and Snail expression. Wound-healing and transwell assays showed that Rg3 could inhibit migration. Meanwhile, Rg3 significantly downregulated the expression of HDAC3 in CSCC cells as detected by real-time quantitative PCR, western blot, and immunofluorescence. Importantly, c-Jun acetylation was increased by the downregulation of HDAC3 with HDAC3 shRNA, and the downregulation was associated with CSCC cell EMT inhibition. Collectively, our results showed that downregulation of HDAC3 by Rg3 or shHDAC3 treatment resulted in c-Jun acetylation, which in turn inhibited CSCC cell EMT. These results indicate that HDAC3 could potentially serve as a therapeutic target therapeutic target for CSCC. Rg3 is an attractive and efficient agent that has oncotherapeutic effects and requires further investigation.

Protective effects of ginsenoside Rg3 on TNF-α-induced human nucleus pulposus cells through inhibiting NF-κB signaling pathway

This work aims to evaluate the effect of ginsenoside Rg3 on the apoptosis, proliferation, extracellular matrix (ECM) metabolism and oxidative stress-induced damage of human nucleus pulposus cells (NPCs) induced by TNF-α. The human NPCs were divided into Control, TNF-α, TNF-α + low Rg3, TNF-α + medium Rg3 and TNF-α + high Rg3 groups. Annexin V-FITC/PI, CCK-8 and flow cytometry were used to detect the apoptosis, proliferation, and cell cycle of NPCs, respectively. The expressions of ECM-related molecules were determined by qRT-PCR, ELISA and Western blotting. NF-κB p65 pathway and apoptosis-related proteins were evaluated by Western blotting, and the production of reactive oxygen species (ROS) was detected by DCFH-DA assay. Compared with Control group, NPCs in the TNF-α group had elevated proportion of apoptotic cells with up-regulation of Bax and Caspase-3 and down-regulation of Bcl-2. Besides, TNF-α inhibited proliferation and arrested cell cycle at G1 of NPCs. Moreover, human NPCs induced by TNF-α presented the increase in the expressions of ECM degrading genes (MMP3 and ADAMTS5), the content of ROS and malondialdehyde (MDA), and the expression of NF-κB/p65 in nucleus, but showed the decrease in the expression of ECM synthesis genes (Aggrecan and COL2A1) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX). However, NPCs treated by both TNF-α and Rg3 demonstrated a certain degree of reversal in the above indexes, which became increasingly evident with the up-regulation of Rg3 concentration. Ginsenoside Rg3 may exert the effect of attenuating TNF-α-induced NPCs impairment via blocking the NF-κB signaling pathway.

Ginsenoside Rg3 stereoisomers differentially inhibit vascular smooth muscle cell proliferation and migration in diabetic atherosclerosis

Ginsenoside 20(R/S)‐Rg3, as a natural peroxisome proliferator‐activated receptor gamma (PPARγ) ligand, has been reported to exhibit differential biological effects. It is of great interest to understand the stereochemical selectivity of 20(R/S)‐Rg3 and explore whether differential PPARγ activation by Rg3 stereoisomers, if it exists, could lead to differential physiological outcome and therapeutic effects in diabetic atherosclerosis. Here, we investigated the binding modes of 20(R/S)‐Rg3 stereoisomers in the PPARγ ligand‐binding domain (PPARγ‐LBD) using molecular modelling and their effects on smooth muscle cell proliferation and migration induced by advanced glycation end products (AGEs). The results revealed that 20(S)‐Rg3 exhibited stronger antiproliferative and antimigratory effects due to stronger PPARγ activation. To validate the in vitro results, we used a mice model with diabetic atherosclerosis and obtained that 20(S)‐Rg3 markedly reduced the plaque size secondary to reducing the proliferation and migration of VSMCs, while the plaques were more stable due to improvements in other plaque compositions. The results shed light on the structural difference between Rg3 stereoisomers that can lead to significant differential physiological outcome, and the (S)‐isomer seems to be the more potent isomer to be developed as a promising drug for diabetic atherosclerosis.

Synergistic anticancer activity of 20(S)-Ginsenoside Rg3 and Sorafenib in hepatocellular carcinoma by modulating PTEN/Akt signaling pathway

Sorafenib, a multikinase inhibitor for hepatocellular carcinoma treatment, inhibits the Raf/MAPK/ERK signaling pathway. However, PI3K/Akt signaling pathway is activated by Sorafenib and cross-talks with the Raf/MAPK/ERK signaling pathway, leading to drug resistance. 20(S)-Ginsenoside Rg3 has been reported with significant anticancer effect to numerous carcinomas by inhibition of PI3K-Akt signaling pathway. Hence, we aim to examine the synergistic anticancer activity of 20(S)-Ginsenoside Rg3 and Sorafenib via modulation of PTEN/Akt signaling pathway. Human hepatocellular carcinoma cell lines HepG2 and Huh7 were used. Cell viability, clonogenic assay, apoptosis assay, western blot analysis, xenograft treatment and immunohistochemistry were carried out. The viability of hepatocellular carcinoma cells significantly decreased by the treatment of Sorafenib combined with 20(S)-Ginsenoside Rg3, as well as the enhanced apoptotic rates. The levels of PTEN, Bax and cleaved caspase-3 expression increased, while the levels of phospho-PDK1 and phospho-Akt expression decreased by the treatment of Sorafenib combined with 20(S)-Ginsenoside Rg3. In vivo, the tumor volumes and weight decreased in the Sorafenib combined with 20(S)-Ginsenoside Rg3 group. The results demonstrated the synergistic anticancer activity of 20(S)-Ginsenoside Rg3 and Sorafenib in HCC by modulating PTEN/Akt signaling pathway. These findings suggest a promising strategy for HCC treatment, which could be performed in a sufficiently frequent manner.

Characterization of the changes in eicosanoid profiles of activated macrophages treated with 20(S)-ginsenoside Rg3

In this study, we used ultra-performance liquid chromatography coupled with tandem mass spectrometry to assess the levels of eicosanoids from RAW264.7 macrophages treated with lipopolysaccharides (LPS) and 20(S)-ginsenoside Rg3 (Rg3). The production of nitric oxide (NO) and the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were increased in inflammatory macrophages treated with LPS. Rg3 treatment, however, decreased the levels of NO, TNF-α, and IL-6 in activated macrophages. Eicosanoids, known as major metabolites correlated with inflammation, have pro- or anti-inflammatory activities. For a detailed characterization of the eicosanoids altered by treatment with LPS and Rg3, the eicosanoids were profiled by multiple reaction monitoring. A total of 69 macrophage eicosanoids were analyzed and the profiling dataset was statistically analyzed. Principal component and hierarchical cluster analyses differentiated control cells from cells treated with LPS, Rg3, or LPS+Rg3 for 12 or 24h. Furthermore, 18 differentially regulated eicosanoids were found between macrophages treated with LPS for 24h and those treated with LPS+Rg3 for 24h (fold change>2, p value<0.05). These results indicate that Rg3 alters eicosanoid metabolism in activated macrophages treated with LPS. Furthermore, we also identified several eicosanoids correlated with the anti-inflammatory activity of Rg3.

Ginsenoside Rg3 attenuates sepsis-induced injury and mitochondrial dysfunction in liver via AMPK-mediated autophagy flux. Biosci Rep. 2017;37. [PMID: 28779013 PMCID: PMC5577177 DOI: 10.1042/bsr20170934]

Sepsis-led mitochondrial dysfunction has become a critical pathophysiological procedure in sepsis. Since ginsenosides have been applied in the treatment of mitochondrial dysfunction, ginsenoside Rg3 was employed to study its effects on the mitochondrial dysfunction induced by sepsis. The apoptosis rate, oxygen consumption rate (OCR), reactive oxygen species (ROS), antioxidant glutathione (GSH) pools, and mitochondrial transmembrane potential (MTP) were determined in LPS-induced sepsis hepatocytes treated with different concentrations of Rg3. Then, the protein expression levels of mitochondrial biogenesis related transcription factors, autophagy-related proteins, and AMP-activated protein kinase (AMPK) signal pathway related proteins were determined by Western blotting in both in vitro and in vivo sepsis models. Rg3 shows functions of promotion of OCR, attenuation of ROS, and maintenance of GSH pools, and its conjugating activity in the in vitro sepsis models. Rg3-treated cells were observed to have a higher MTP value compared with the LPS only induced cells. Moreover, Rg3 treatment can inhibit mitochondrial dysfunction via increasing the protein expression levels of mitochondrial biogenesis related transcription factors. Rg3 treatment has the function of inhibitor of apoptosis of human primary hepatocytes, and Rg3 can up-regulate the autophagy-related proteins and activate AMPK signal pathway in sepsis models. Meanwhile, the mitochondrial protective function exerted by Rg3 decreased after the autophagy inhibitors or AMPK inhibitor treatment in LPS-induced human primary hepatocytes. Rg3 can improve mitochondrial dysfunction by regulating autophagy in mitochondria via activating the AMPK signal pathway, thus protecting cell and organ injuries caused by sepsis.

Molecular signaling of ginsenosides Rb1, Rg1, and Rg3 and their mode of actions

Ginseng has gained its popularity as an adaptogen since ancient days because of its triterpenoid saponins, known as ginsenosides. These triterpenoid saponins are unique and classified as protopanaxatriol and protopanaxadiol saponins based on their glycosylation patterns. They play many protective roles in humans and are under intense research as various groups continue to study their efficacy at the molecular level in various disorders. Ginsenosides Rb1 and Rg1 are the most abundant ginsenosides present in ginseng roots, and they confer the pharmacological properties of the plant, whereas ginsenoside Rg3 is abundantly present in Korean Red Ginseng preparation, which is highly known for its anticancer effects. These ginsenosides have a unique mode of action in modulating various signaling cascades and networks in different tissues. Their effect depends on the bioavailability and the physiological status of the cell. Mostly they amplify the response by stimulating phosphotidylinositol-4,5-bisphosphate 3-kinase/protein kinase B pathway, caspase-3/caspase-9-mediated apoptotic pathway, adenosine monophosphate-activated protein kinase, and nuclear factor kappa-light-chain-enhancer of activated B cells signaling. Furthermore, they trigger receptors such as estrogen receptor, glucocorticoid receptor, and N-methyl-d-aspartate receptor. This review critically evaluates the signaling pathways attenuated by ginsenosides Rb1, Rg1, and Rg3 in various tissues with emphasis on cancer, diabetes, cardiovascular diseases, and neurodegenerative disorders.

Ginsenoside Rg3 inhibits epithelial-mesenchymal transition (EMT) and invasion of lung cancer by down-regulating FUT4

The epithelial-mesenchymal transition (EMT) is an important factor in lung cancer metastasis, and targeting EMT is a potential therapeutic strategy. Fucosyltransferase IV (FUT4) and its synthetic cancer sugar antigen Lewis Y (LeY) was abnormally elevated in many cancers. In this study, a traditional Chinese medicine ginsenoside Rg3 was used to investigate whether its inhibition to EMT and invasion of lung cancer is by the glycobiology mechanism. We found that Rg3 treatment (25, 50, 100 μg/ml) inhibited cell migration and invasion by wound-healing and transwell assays. Rg3 could significantly alter EMT marker proteins with increased E-cadherin, but decreased Snail, N-cadherin and Vimentin expression. Rg3 also down-regulated FUT4 gene and protein expression in lung cancer cells by qPCR, Western blot and immunofluorescence. After FUT4 down-regulated with shFUT4, EMT was obviously inhibited. Furthermore, the activation of EGFR through decreased LeY biosynthesis was inhibited, which blocked the downstream MAPK and NF-κB signal pathways. In addition, Rg3 reduced tumor volume and weight in xenograft mouse model, and significantly decreased tumor metastasis nodules in lung tissues by tail vein injection. In conclusion, Rg3 inhibits EMT and invasion of lung cancer by down-regulating FUT4 mediated EGFR inactivation and blocking MAPK and NF-κB signal pathways. Rg3 may be a potentially effective agent for the treatment of lung cancer.

pylori CagA-treated gastric cancer cells by regulating SP1 and HSF1 expressions

Helicobacter pylori (H. pylori) cytotoxin associated antigen A (CagA) plays a significant role in the development of gastric cancer. Ginsenoside Rg3 is a herbal medicine which inhibits cell proliferation and induces apoptosis in various cancer cells. Fucosylation plays important roles in cancer biology as increased fucosylation levels of glycoproteins and glycolipids have been reported in many cancers. Fucosyltransferase IV (FUT4) is an essential enzyme, catalyzes the synthesis of LewisY oligosaccharides and is regulated by specificity protein 1 (SP1) and heat shock factor protein 1 (HSF1) transcription factors. Herein, we studied the mechanism action of Rg3 apoptosis induction in gastric cancer cells. We treated the gastric cancer cells with CagA followed by Rg3, and analyzed their ability to induce apoptosis by evaluating the role of FUT4 as well as SP1 and HSF1 expressions by Western blot, flow cytometry and ELISA. We found that Rg3 significantly induced apoptosis in CagA treated gastric cancer cells, as evidenced by nuclear staining of 4-6-diamidino-2-phenylindole (DAPI) and Annexin-V/PI double-labeling. In addition, Rg3 significantly increased the expression of pro-apoptotic proteins and triggered the activation of caspase-3, -8, and -9 and PARP. Moreover, Rg3-induced apoptotic mechanisms indicated that Rg3 inhibited FUT4 expression through SP1 upregulation and HSF1 downregulation. Hence, Rg3 therapy is an effective strategy for gastric cancer treatment. Furthermore SP1 and HSF1 may serve as potential diagnostic and therapeutic targets for gastric cancer.

Influence of As2O3 combined with ginsenosides Rg3 on inhibition of lung cancer NCI-H1299 cells and on subsistence of nude mice bearing hepatoma

OBJECTIVES

To study the effect of arsenic trioxide (As2O3) combined with ginsenosides Rg3 on inhibiting the NCI-H1299 lung cancer cells and subsistence in nude mice bearing hepatoma.

METHODS

MTT method was used to measure the inhibition effect of As2O3 combined Rg3 on NCI-H1299 cells, and the proliferation inhibiting effect was observed via establishing the transplanted tumor model in vitro. A total of 40 tumor-bearing nude mice were randomly divided into normal saline group, As2O3, Rg3 and As2O3+Rg3 group. Transplantation tumor model of lung cancer in nude mice was constructed, followed by injection of certain concentrations of normal saline, As2O3, ginseng saponin Rg3 and As2O3+Rg3 every day. The survival duration and the tumors size of the mice were recorded and the Kaplan-Meier curve was made; microscopic observation of apoptosis of tumor cells in vivo was done using TUNEL staining.

RESULTS

After 72 h of injection, inhibition rate of tumor cell in normal saline group, As2O3 group, Rg3 group and As2O3+Rg3 group was (5.66±0.31)%, (65.58±4.75)%, (44.69±3.32)% and (82.67±5.43)%, respectively. Inhibition rate of tumor cell in As2O3 group, Rg3 group and As2O3+Rg3 group was significantly higher than that of normal saline group (P<0.01); inhibition rate of tumor cells of As2O3+Rg3 group was significantly higher than that of the two groups given As2O3 or Rg3 alone (P<0.01). The tumor volume of As2O3 group, Rg3 group and As2O3+Rg3 group shrank to (65.38±3.25)%, (77.68±3.43)% and (42.65±3.55)% of the original, tumor volume of saline group was 1.21 times of the original size (P<0.01); Median survival of saline group, Rg3 group, As2O3 group were significantly shorter than that of As2O3+Rg3 group (P<0.01); co-ordinated intervention ability of As2O3+Rg3 on NCI-H1299 cell was significantly higher than that of As2O3 or Rg3, separately.

CONCLUSIONS

As2O3 combined with Rg3 can significantly inhibit proliferation of NCI-H1299 cells in lung cancer, prolong survival of tumor-bearing nude mice, and promote tumor cell apoptosis, and have significant effect on lung cancer treatment.

An Aβ42 uptake and degradation via Rg3 requires an activation of caveolin, clathrin and Aβ-degrading enzymes in microglia

We demonstrated previously that ginsenoside Rg3 enhances the expression of macrophage scavenger receptor class A (SRA) and amyloid β peptide 1-42 (Aβ42) uptake in BV2 cells. In this study, we investigated the biochemical and mechanistic roles of Rg3 in human microglia and animal models to identify the determinants that participate in restoring memory and learning in brains disrupted by the Aβ42 peptide. SRA was expressed highly in Rg3-treated rats, and learning and memory functions were maintained at a normal level after the infusion of Aβ42. SRA-transfected HMO6 human microglial cells (HMO6.hSRA) overexpressed SRA and took up a remarkable amount of Aβ42. Rg3-treated HMO6 cells showed highly enhanced SRA expression and dramatically promoted Aβ42 uptake. Moreover, high levels of clathrin and caveolin1 supported the roles of Rg3 in endocytic biogenesis by activating p38 and extracellular signal-regulated protein kinase signaling. Notably, both neprilysin (NEP) and insulin-degrading enzyme (IDE) were significantly expressed by Rg3, suggesting independent and compensatory hydrolytic activity for the Aβ peptide. In conclusion, Rg3 successfully triggered Aβ42 uptake via SRA and clathrin-/caveolae-mediated endocytic mechanisms and further contributed to accelerate the degradation of Aβ peptide via the increase of intracellular NEP and IDE, which may be a promising Alzheimer׳s disease therapy.

Ginsenoside Rg3 Induces Apoptosis of Human Breast Cancer (MDA-MB-231) Cells

Background:

Rg₃, a major ginsenoside derived from heat-processed ginseng, has been reported to have anti-inflammatory and anti-proliferative activities. In our previous studies, Rg₃ inhibited phorbol ester-induced cyclooxygenase-2 expression and NF-κB activation in cultured human mammary epithelial (MCF-10A) cells and in mouse skin in vivo. In this study, we investigated Rg₃-induced apoptosis in human breast cancer (MDA-MB-231) cells and underlying molecular mechanisms.

Methods:

After Rg3 treatment, apoptotic cell death of MDA-MB-231 cell was investigated by the MTT reduction assay and measurement of the mitochondrial membrane depolarization. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells as well as measurement of reactive oxygen species. Expression of apoptotic-related proteins was determined by immunoblot analysis.

Results:

MDA-MB-231 cells treated with Rg₃ (30μM) exhibited the increased proportion of hypodiploid or apoptotic cells. Rg₃ treatment resulted in an increase in the ratio of proapoptotic Bax to antiapoptotic Bcl-2, depolarization of the mitochondria membrane potential and the release of cytochrome c from mitochondria. Rg₃ also induced the proteolytic cleavage of caspase-3 and poly (ADP-ribose) polymerase, which was attenuated by a caspase-3 inhibitor, z-VAD-fmk.

Conclusions:

Based on these findings, it is likely that Rg₃ induces apoptosis in MDA-MB-231 cells via classical mitochondria-dependent caspase activation. These data suggest that Rg₃ might be a potential candidate as a breast cancer chemopreventive agent.

Ginsenoside Rg3 inhibits HIF-1α and VEGF expression in patient with acute leukemia via inhibiting the activation of PI3K/Akt and ERK1/2 pathways

Aberrant angiogenesis is essential to the development and progression of leukemia. Ginsenoside Rg3 has been commonly used in anti-angiogenic therapy of solid tumors. This study aimed to investigate the anti-angiogenic effects of Rg3 in patients with acute leukemia. Bone marrow stromal cells derived from patients with acute leukemia were treated with Rg3 and the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1α (HIF-1α) was detected by RT-PCR and western blot analysis. The results showed that Rg3 inhibited VEGF and HIF-1α expression at both mRNA and protein levels in bone marrow stromal cells. In addition, Rg3 treatment led to reduced serum levels of HIF-1α and VEGF in patients with acute leukemia. Mechanistically, we demonstrated that Rg3 downregulated the phosphorylation of Akt and ERK1/2 in BMSCs. In conclusion, Rg3 exhibits anti-leukemia effect in part due to its anti-angiogenic activity via inhibiting PI3K/Akt and ERK1/2 pathways, which act to regulate the expression of HIF-1α and VEGF.

Synergistic effect of ginsenoside Rg3 with verapamil on the modulation of multidrug resistance in human acute myeloid leukemia cells

The pharmacological modulatory effects of 20(S)-ginsenoside Rg3 (20S-Rg3) on multidrug resistant cancer cells are reported in the present study. The effects of 20(S)-Rg3 on the modulation of doxorubicin (DOX) and vincristine (VCR) resistance were examined in the HL60 multidrug resistant subline of human acute myeloid leukemia cells. Results demonstrated that 20S-Rg3 is as effective as verapamil (Vp) for modulating the high degree primary DOX resistance and low degree VCR cross-resistance expressed by the H160 cell line. Furthermore, the present study demonstrates for the first time, using isobologram analysis, that the combination of 20S-Rg3 and Vp enhances the reversal of DOX and VCR resistance in a supra-additive or at least an additive manner. These results indicate that 20S-Rg3 may be used as a Vp synergizer or as a promising alternative to Vp in the chemosensitization of multidrug resistant acute myeloid leukemia, with far fewer side effects.

Ginsenoside Rg3 up-regulates the expression of vascular endothelial growth factor in human dermal papilla cells and mouse hair follicles

Crude Panax ginseng has been documented to possess hair growth activity and is widely used to treat alopecia, but the effects of ginsenoside Rg3 on hair growth have not to our knowledge been determined. The aim of the current study was to identify the molecules through which Rg3 stimulates hair growth. The thymidine incorporation for measuring cell proliferation was determined. We used DNA microarray analysis to measure gene expression levels in dermal papilla (DP) cells upon treatment with Rg3. The mRNA and protein expression levels of vascular endothelial growth factor (VEGF) in human DP cells were measured by real-time polymerase chain reaction and immunohistochemistry, respectively. We also used immunohistochemistry assays to detect in vivo changes in VEGF and 3-stemness marker expressions in mouse hair follicles. Reverse transcription polymerase chain reaction showed dose-dependent increases in VEGF mRNA levels on treatment with Rg3. Immunohistochemical analysis showed that expression of VEGF was significantly up-regulated by Rg3 in a dose-dependent manner in human DP cells and in mouse hair follicles. In addition, the CD8 and CD34 were also up-regulated by Rg3 in the mouse hair follicles. It may be concluded that Rg3 might increase hair growth through stimulation of hair follicle stem cells and it has the potential to be used in hair growth products.

Effects of ginseol k-g3, an Rg3-enriched fraction, on scopolamine-induced memory impairment and learning deficit in mice

Background

Although ginsenosides such as Rg1, Rb1 and Rg3 have shown promise as potential nutraceuticals for cognitive impairment, their use has been limited due to high production cost and low potency. In particular, the process of extracting pure Rg3 from ginseng is laborious and expensive.

Methods

We described the methods in preparing ginseol k-g3, an Rg3-enriched fraction, and evaluated its effects on scopolamine-induced memory impairment in mice.

Results

Ginseol k-g3 (25–200 mg/kg) significantly reversed scopolamine-induced cognitive impairment in the passive avoidance, but not in Y-maze testing. Ginseol k-g3 (50 and 200 mg/kg) improved escape latency in training trials and increased swimming times within the target zone of the Morris water maze. The effect of ginseol k-g3 on the water maze task was more potent than that of Rg3 or Red ginseng. Acute or subchronic (6 d) treatment of ginseol k-g3 did not alter normal locomotor activity of mice in an open field. Ginseol k-g3 did not inhibit acetylcholinesterase activity, unlike donezepil, an acetylcholinesterase inhibitor. Rg3 enrichment through the ginseol k-g3 fraction enhanced the efficacy of Rg3 in scopolamine-induced memory impairment in mice as demonstrated in the Morris water maze task.

Conclusion

The effects of ginseol k-g3 in ameliorating scopolamine-induced memory impairment in the passive avoidance and Morris water maze tests indicate its specific influence on reference or long-term memory. The mechanism underlying the reversal of scopolamine-induced amnesia by ginseol k-g3 is not yet known, but is not related to anticholinesterase-like activity.

Effect of ginsenoside Rg3 on tyrosine hydroxylase and related mechanisms in the forced swimming-induced fatigue rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ginsenoside Rg3 has shown multiple pharmacological activities and been considered as one of the most promising approaches for fatigue treatment. However, little is known about the cellular and molecular mechanisms of Rg3 on anti-fatigue and the effect of Rg3 on dopaminergic system has not been reported yet. The major aim of this study is to investigate the effect of Rg3 on TH expression and the related biochemical parameters, such as PKAα, ERK1/2, Akt and α-synuclein in brain of fatigue rats.

MATERIALS AND METHODS

Weight-loaded forced swimming was performed to establish an animal model of fatigue. Rg3 (10mg/kg, 50mg/kg and 100mg/kg) was intragastrically administrated before swimming. The effect of Rg3 on the expression and phosphorylation of TH and TH-related proteins in fatigue rats or in SH-SY5Y cells was assessed with western blotting. HPLC was used to examine the level of DA and DOPAC in the fatigue rats tissues.

RESULTS

TH and phosphorylated TH were decreased in different brain regions of which ventral midbrain were less affected in weight-loaded forced swimming rats. Pretreatment with Rg3 significantly suppressed fatigue-induced decrease expression of TH and TH phosphorylation. Also treatment with Rg3 reversed the decrease expression of PKAα as well as the phosphorylation of ERK1/2 and Akt which were induced by weight-loaded forced swimming. Moreover, weight-loaded swimming could induce the increase expression of α-synuclein in hippocampus and midbrain, while suppressed α-synuclein expression in striatum and prefrontal cortex. Furthermore, Rg3 could induce the increase of TH expression and phosphorylation which was accompanied with elevated expression and phosphorylation of related kinase proteins in vitro, while the inhibitors of kinase proteins could suppress these effects of Rg3. In addition, HPLC results showed that Rg3 could reverse the weight-loaded swimming-induced increase of DOPAC/DA ratio.

CONCLUSION

Our data suggest that fatigue can induce the decrease of DA which might partially result from the change of TH expression and phosphorylation, and Rg3 can reverse these fatigue-induced changes. The underling mechanisms may include the activity changes of PKAα, ERK1/2, Akt and α-synuclein.