Ginsenoside Re inhibits pacemaker potentials via adenosine triphosphate-sensitive potassium channels and the cyclic guanosine monophosphate/nitric oxide-dependent pathway in cultured interstitial cells of Cajal from mouse small intestine

A comprehensive system review of pharmacological effects and relative mechanisms of Ginsenoside Re: Recent advances and future perspectives

BACKGROUND

Ginsenoside Re (Re) belongs to protopanaxatriol saponins and exists in Panax ginseng, Panax quinquefolium, Panax notoginseng, and other plants in the Araliaceae family. Re has recently become a research focus owing to its pharmacological activities and benefits to human bodies.

PURPOSE

To summarize recent findings regarding the pharmacological effects and mechanisms of Re and highlight and predict the potential therapeutic effects and systematic mechanism of Re.

METHODS

Recent studies (2011-2021) on the pharmacological effects and mechanisms of Re were retrieved from Web of Science, PubMed, Google Scholar, Scopus, and Embase up to December 2021 using relevant keywords. Network pharmacology and bioinformatics analysis were used to predict the therapeutic effects and mechanisms of Re against potential diseases.

RESULTS

Re presented a wide range of therapeutic and biological activities, including neuroprotective, cardiovascular, antidepressant, antitumorigenic, and others effects. The related pharmacological mechanisms of Re include the regulation of cholinergic and antioxidant systems in the brain; the induction of tumor cell apoptosis; the inhibition of tau protein hyperphosphorylation and oxidative stress; the activation of p38MAPK, ERK1/2, and JNK signals; the improvement of lipid metabolism; and the reduction of endothelial cell dysfunction.

CONCLUSION

This paper summarizes comprehensively the current research progress of Re and provides new research insights into the therapeutic effects and mechanisms of Re against potential diseases.

Trypsin Depolarizes Pacemaker Potentials in Murine Small Intestinal Interstitial Cells of Cajal

Interstitial cells of Cajal (ICCs) generate pacemaker potentials in the gastrointestinal (GI) tract. In this study, the effects of trypsin on pacemaker potentials in murine small intestinal ICCs were examined. We used whole-cell patch-clamp analysis. The results of whole-cell patch-clamp analysis revealed that trypsin dose-dependently depolarized pacemaker potentials and decreased their amplitude. Treatments with the antagonists of neurokinin1 (NK1) and NK2 receptors (SR-140333 and SR-48968, respectively) slightly inhibited the trypsin-induced responses. However, treatment with the combination of SR-140333 and SR-48968 completely inhibited trypsin-induced responses. Trypsin slightly depolarized pacemaker potentials and increased their amplitude after the intracellular application of GDP-β-S. Additionally, incubation in external Ca2+-free solution inhibited trypsin-induced responses. In the presence of U-73122, staurosporine, Go6976, or xestospongin C, trypsin did not depolarize the pacemaker’s potentials. However, trypsin depolarized the pacemaker potentials in the presence of rottlerin. Finally, HC067047, a TRPV4 inhibitor, did not affect the trypsin-induced responses. These results suggest that trypsin depolarized pacemaker potentials through NK1 and NK2 receptors in the murine small intestinal ICCs, with this effect being dependent on the G protein, phospholipase C, protein kinase C, inositol triphosphate pathways, and extracellular Ca2+ but being independent of the TRPV4 pathway. Hence, trypsin-mediated GI motility regulation must be considered for prokinetic drug developments.

Pharmacological Properties of Ginsenoside Re

Ginsenoside Re is a protopanaxatriol-type saponin extracted from the berry, leaf, stem, flower bud, and root of Panax ginseng. In recent years, ginsenoside Re (Re) has been attracting attention as a dietary phytochemical. In this review, studies on Re were compiled by searching a combination of keywords, namely “pharmacology,” “pharmacokinetics,” and “toxicology,” in the Google Scholar, NCBI, PubMed, and Web of Science databases. The aim of this review was to provide an exhaustive overview of the pharmacological activities, pharmacokinetics, and toxicity of Re, focusing on clinical evidence that has shown effectiveness in specific diseases, such as diabetes mellitus, nervous system diseases, inflammation, cardiovascular disease, and cancer. Re is also known to eliminate virus, enhance the immune response, improve osteoporosis, improve skin barrier function, enhance intracellular anti-oxidant actions, regulate cholesterol metabolism, alleviate allergic responses, increase sperm motility, reduce erectile dysfunction, promote cyclic growth of hair follicles, and reduce gastrointestinal motility dysfunction. Furthermore, this review provides data on pharmacokinetic parameters and toxicological factors to examine the safety profile of Re. Such data will provide a theoretical basis and reference for Re-related studies and future applications.

Effects of Chaihu-Shugan-San on Small Intestinal Interstitial Cells of Cajal in Mice

Chaihu-Shugan-San (CSS) has been widely used as an alternative treatment for gastrointestinal (GI) diseases in East Asia. Interstitial cells of Cajal (ICCs) are pacemakers in the GI tract. In the present study, we examined the action of CSS on pacemaker potentials in cultured ICCs from the mouse small intestine in vitro and on GI motility in vivo. We used the electrophysiological methods to measure the pacemaker potentials in ICCs. GI motility was investigated by measuring intestinal transit rates (ITR). CSS inhibited the pacemaker potentials in a dose-dependent manner. The capsazepine did not block the effect of CSS. However, the effects of CSS were blocked by glibenclamide. In addition, N^G-nitro-L-arginine methyl ester (L-NAME) also blocked the CSS-induced effects. Pretreatment with SQ-22536 or with KT-5720 did not suppress the effects of CSS; however, pretreatment with ODQ or KT-5823 did. Furthermore, CSS significantly suppressed murine ITR enhancement by neostigmine in vivo. These results suggest that CSS exerts inhibitory effects on the pacemaker potentials of ICCs via nitric oxide (NO)/cGMP and ATP-sensitive K⁺ channel dependent and transient receptor potential vanilloid 1 (TRPV1) channel independent pathways. Accordingly, CSS could provide the basis for the development of new treatments for GI motility dysfunction.

Depolarization of pacemaker potentials by caffeic acid phenethyl ester in interstitial cells of Cajal from the murine small intestine

Interstitial cells of Cajal (ICCs) are pacemaker cells in the gastrointestinal (GI) tract and generate pacemaker potentials. In this study, we investigated the effects of caffeic acid phenethyl ester (CAPE) on the pacemaker potentials of ICCs from the mouse small or large intestine. Using the whole-cell patch-clamp configuration, we found that CAPE depolarized the pacemaker potentials of cultured ICCs from the murine small intestine in a dose-dependent manner. The estrogen receptor (ER) β antagonist PHTPP completely inhibited CAPE-induced depolarization, but the ERα antagonist BHPI did not. Intracellular GDP-β-S and pretreatment with Ca²⁺-free solution or thapsigargin also blocked CAPE-induced depolarization. To investigate the mechanisms of CAPE-mediated depolarization of ICCs, we used the nonselective cation channel (NSCC) inhibitor flufenamic acid, the Cl^- channel blocker, mitogen-activated protein kinase (MAPK) inhibitors PD98059, SB203580, or SP600125, and PI3 kinase inhibitor LY294002. All inhibitors blocked the CAPE-induced pacemaker potential depolarization of ICCs. These results suggest that CAPE induces pacemaker potential depolarization through ERβ in a G protein, NSCC, Cl^- channel, MAPK- and PI3 kinase dependent manner via intracellular and extracellular Ca²⁺ regulation in the murine small intestine. CAPE may therefore modulate GI motility by acting on ICCs in the murine small intestine.

The Mechanism of Action of Ghrelin and Motilin in the Pacemaker Potentials of Interstitial Cells of Cajal from the Murine Small Intestine

Interstitial cells of Cajal (ICCs) are pacemaker cells that exhibit periodic spontaneous depolarization in the gastrointestinal (GI) tract and generate pacemaker potentials. In this study, we investigated the effects of ghrelin and motilin on the pacemaker potentials of ICCs isolated from the mouse small intestine. Using the whole-cell patch-clamp configuration, we demonstrated that ghrelin depolarized pacemaker potentials of cultured ICCs in a dose-dependent manner. The ghrelin receptor antagonist [D-Lys] GHRP-6 completely inhibited this ghrelin-induced depolarization. Intracellular guanosine 5'-diphosphate-β-S and pre-treatment with Ca2+free solution or thapsigargin also blocked the ghrelin-induced depolarization. To investigate the involvement of inositol triphosphate (IP3), Rho kinase, and protein kinase C (PKC) in ghrelin-mediated pacemaker potential depolarization of ICCs, we used the IP3 receptor inhibitors 2-aminoethoxydiphenyl borate and xestospongin C, the Rho kinase inhibitor Y-27632, and the PKC inhibitors staurosporine, Go6976, and rottlerin. All inhibitors except rottlerin blocked the ghrelin-induced pacemaker potential depolarization of ICCs. In addition, motilin depolarized the pacemaker potentials of ICCs in a similar dose-dependent manner as ghrelin, and this was also completely inhibited by [D-Lys] GHRP-6. These results suggest that ghrelin induced the pacemaker potential depolarization through the ghrelin receptor in a G protein-, IP3-, Rho kinase-, and PKC-dependent manner via intracellular and extracellular Ca2+ regulation. In addition, motilin was able to depolarize the pacemaker potentials of ICCs through the ghrelin receptor. Therefore, ghrelin and its receptor may modulate GI motility by acting on ICCs in the murine small intestine.

Ginsenoside Re inhibits PDGF-BB-induced VSMC proliferation via the eNOS/NO/cGMP pathway

Ginsenoside Re (GS-Re), which is a major monomeric member of the ginseng trialcohol saponin family, is one of the main active components of ginseng and plays an important role in protecting the cardiovascular system. Here, we report a novel function by which GS-Re regulates the eNOS/NO/cGMP pathway, which affects the platelet-derived growth factor-BB (PDGF-BB)-induced proliferation of vascular smooth muscle cells (VSMCs). GS-Re inhibited PDGF-BB-induced VSMC proliferation in a concentration-dependent manner without cytotoxicity, and the endothelial nitric oxide synthase (eNOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) antagonized the antiproliferative effect of GS-Re. The flow cytometry analysis suggested that GS-Re regulates VSMC proliferation by influencing the cell cycle transition from G0/G1 to S phase and decreasing the expression of G0/G1-specific regulatory proteins, including proliferating cell nuclear antigen (PCNA), cyclin D1, and CDK4, in PDGF-BB-treated VSMCs, consequently upregulating the protein expression of p21. After GS-Re treatment, the levels of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) and the phos-eNOS ^Ser1177/eNOS protein ratio were obviously increased. In addition, treatment with L-NAME blocked the eNOS/NO/cGMP signaling pathway, and the protein levels of PCNA, cyclin D1, and CDK4 were markedly increased in GS-Re-treated VSMCs, while p21 expression was decreased in PDGF-BB-induced VSMCs. Overall, these findings reveal that GS-Re can inhibit the proliferation of VSMCs through G0/G1 cell cycle arrest, which is closely related to eNOS/NO/cGMP pathway activation. The present results provide basic pharmacological evidence of the potential prevention and treatment of cardiovascular diseases by GS-Re.

Modulation of Pacemaker Potentials in Murine Small Intestinal Interstitial Cells of Cajal by Gamisoyo-San, a Traditional Chinese Herbal Medicine

BACKGROUND

The Gamisoyo-san (GSS) has been used for -improving the gastrointestinal (GI) symptoms. The purpose of this study was to investigate the effects of GSS, a traditional Chinese herbal medicine, on the pacemaker potentials of mouse small intestinal interstitial cells of Cajal (ICCs).

METHODS

ICCs from the small intestines were dissociated and cultured. Whole-cell patch-clamp configuration was used to record pacemaker potentials and membrane currents.

RESULTS

GSS depolarized ICC pacemaker potentials in a dose-dependent manner. Pretreatment with 4-diphenylacetoxypiperidinium iodide completely inhibited GSS-induced pacemaker potential depolarizations. Intracellular GDP-β-S inhibited GSS-induced effects, and in the presence of U-73122, GSS-induced effects were inhibited. Also, GSS in the presence of a Ca2+-free solution or thapsigargin did not depolarize pacemaker potentials. However, in the presence of calphostin C, GSS slightly depolarized pacemaker potentials. Furthermore, GSS inhibited both transient receptor potential melastatin7 and Ca2+-activated Cl- channel (anoctamin1) currents.

CONCLUSION

GSS depolarized pacemaker potentials of ICCs via G protein and muscarinic M3 receptor signaling pathways and through internal or external Ca2+-, phospholipase C-, and protein kinase C-dependent and transient receptor potential melastatin 7-, and anoctamin 1-independent pathways. The study shows that GSS may regulate GI tract motility, suggesting that GSS could be a basis for developing novel prokinetic agents for treating GI motility dysfunctions.

Ginsenoside Re inhibits vascular neointimal hyperplasia in balloon-injured carotid arteries through activating the eNOS/NO/cGMP pathway in rats

Ginsenoside Re (GS-Re) is one of the main ingredients of ginseng, a widely known Chinese traditional medicine, and has a variety of beneficial effects, including vasorelaxation, antioxidative, anti-inflammatory, and anticancer properties. The aims of the present study were to observe the effect of GS-Re on balloon injury-induced neointimal hyperplasia in the arteries and to investigate the mechanisms underlying this effect. A rat vascular neointimal hyperplasia model was generated by rubbing the endothelium of the common carotid artery (CCA) with a balloon, and GS-Re (12.5, 25 or 50 mg/kg/d) were subsequently continuously administered to the rats by gavage for 14 days. After GS-Re treatment, the vessel lumen of injured vessels showed significant increases in the GS-Re 25.0 and 50.0 mg/kg/d (intermediate- and high-dose) groups according to H.E. staining. Additionally, a reduced percentage of proliferating cell nuclear antigen (PCNA)-positive cells and an increased number of SM α-actin-positive cells were detected, and the levels of NO, cyclic guanosine monophosphate (cGMP), and eNOS mRNA as well as the phos-eNOS^ser1177/eNOS protein ratio were obviously upregulated in the intermediate- and high-dose groups. Moreover, the promotive effects of GS-Re on NO and eNOS expression were blocked by L-NAME treatment to different degrees. These results suggested that GS-Re can suppress balloon injury-induced vascular neointimal hyperplasia by inhibiting VSMC proliferation, which is closely related to the activation of the eNOS/NO/cGMP pathway.

Depolarizing Effects of Daikenchuto on Interstitial Cells of Cajal from Mouse Small Intestine

Background:

Daikenchuto (DKT; TJ-100, TU-100), a traditional herbal medicineis used in modern medicine to treat gastrointestinal (GI) functional disorders. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the GI tract and play important roles in the regulation of GI motility.

Objective:

The objective of this study was to investigate the effects of DKT on the pacemaker potentials (PPs) of cultured ICCs from murine small intestine.

Materials and Methods:

Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues. All experiments on ICCs were performed after 12 h of culture. The whole-cell patch-clamp configuration was used to record ICC PPs (current clamp mode). All experiments were performed at 30-32°C.

Results:

In current-clamp modeDKT depolarized and concentration-dependently decreased the amplitudes of PPs. Y25130 (a 5-HT₃ receptor antagonist) or SB269970 (a 5-HT₇ receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT₄ receptor antagonist) did. Methoctramine (a muscarinic M₂ receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-diphenylacetoxy-N-methylpiperidine methiodide (a muscarinic M₃ receptor antagonist) facilitated blockade of DKT-induced PP depolarization. Pretreatment with an external Ca²⁺-free solution or thapsigargin abolished PPsand under these conditions, DKT did not induce PP depolarization. Furthermore Ginseng radix and Zingiberis rhizomes depolarized PPs, whereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs.

Conclusion:

These results suggest that DKT depolarizes ICC PPs in an internal or external Ca²⁺-dependent manner by stimulating 5-HT₄ and M₃ receptors. Furthermore, the authors suspect that the component in DKT largely responsible for depolarization is probably also a component of Ginseng radix and Zingiberis rhizomes.

SUMMARY

Daikenchuto (DKT) depolarized and concentration-dependently decreased the amplitudes of pacemaker potentials (PPs)

Y25130 (a 5-HT₃ receptor antagonist) or SB269970 (a 5-HT₇ receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT₄ receptor antagonist) did

Methoctramine (a muscarinic M₂ receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-DAMP (a muscarinic M₃ receptor antagonist) facilitated blockade of DKT-induced PP depolarization

Ginseng radix and Zingiberis rhizomes depolarized PPswhereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs.

Abbreviation used: DKT: Daikenchuto, GI: Gastrointestinal, ICCs: Interstitial cells of Cajal, PPs: Pacemaker Potentials.