Network pharmacology-based approach uncovers the pharmacodynamic components and mechanism of Fructus Tribuli for improving endothelial dysfunction in hypertension.

ETHNOPHARMACOLOGICAL RELEVANCE: Fructus Tribuli (FT), a traditional Chinese medicinal herbal, has been used for the clinical treatment of cardiovascular diseases for many years and affects vascular endothelial dysfunction (ED) in patients with hypertension. AIM OF THE STUDY: This study aimed to demonstrate the pharmacodynamic basis and mechanisms of FT for the treatment of ED. MATERIALS AND METHODS: The present study used ultra-high-performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) to analyze and identify the chemical components of FT. The active components in blood were determined after the oral administration of FT by comparative analysis to blank plasma. Then, based on the active components in vivo, network pharmacology was performed to predict the potential targets of FT in treating ED. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were also performed, and component-target-pathway networks were constructed. Interactions between the major active components and main targets were verified by molecular docking. Moreover, spontaneously hypertensive rats (SHRs) were divided into the normal, model, valsartan, low-dose FT, medium-dose FT, and high-dose FT experimental groups. In pharmacodynamic verification studies, treatment effects on blood pressure, serum markers (nitric oxide [NO], endothelin-1 [ET-1,], and angiotensin Ⅱ [Ang Ⅱ)]) of ED, and endothelial morphology of the thoracic aorta were evaluated and compared between groups. Finally, the PI3K/AKT/eNOS pathway was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot of the thoracic aorta of rats in each group to detect the mRNA expression of PI3K, AKT, and eNOS and the protein expression of PI3K, AKT, p-AKT, eNOS, and p-eNOS. RESULTS: A total of 51 chemical components were identified in FT, and 49 active components were identified in rat plasma. Thirteen major active components, 22 main targets, and the PI3K/AKT signaling pathway were screened by network pharmacology. The animal experiment results showed that FT reduced systolic blood pressure and ET-1 and Ang Ⅱ levels and increased NO levels in SHRs to varying degrees. The therapeutic effects were positively correlated with the oral dose of FT. Hematoxylin-eosin (HE) staining confirmed that FT could alleviate the pathological damage of the vascular endothelium. qRT-PCR and Western blot analysis confirmed that up-regulated expression of the PI3K/AKT/eNOS signaling pathway could improve ED. CONCLUSIONS: In this study, the material basis of FT was comprehensively identified, and the protective effect on ED was confirmed. FT had a treatment effect on ED through multi-component, multi-target, and multi-pathways. It also played a role by up-regulating the PI3K/AKT/eNOS signaling pathway.

Influence of electroacupuncture on ghrelin and the phosphoinositide 3-kinase/protein kinase B/endothelial nitric oxide synthase signaling pathway in spontaneously hypertensive rats.

OBJECTIVE: To investigate the influence of electroacupuncture (EA) on ghrelin and the phosphoinositide 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling pathway in spontaneously hypertensive rats (SHRs). METHODS: Eight Wistar-Kyoto rats were used as the healthy blood pressure (BP) control (normal group), and 32 SHRs were randomized into model group, EA group, EA plus ghrelin group (EA + G group), and EA plus PF04628935 group (a potent ghrelin receptor blocker; EA + P group) using a random number table. Rats in the normal group and model group did not receive treatment, but were immobilized for 20 min per day, 5 times a week, for 4 continuous weeks. SHRs in the EA group, EA + G group and EA + P group were immobilized and given EA treatment in 20 min sessions, 5 times per week, for 4 weeks. Additionally, 1 h before EA, SHRs in the EA + G group and EA + P group were intraperitoneally injected with ghrelin or PF04628935, respectively, for 4 weeks. The tail-cuff method was used to measure BP. After the 4-week intervention, the rats were sacrificed by cervical dislocation, and pathological morphology of the abdominal aorta was observed using hematoxylin-eosin (HE) staining. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of ghrelin, nitric oxide (NO), endothelin-1 (ET-1) and thromboxane A2 (TXA2) in the serum. Isolated thoracic aortic ring experiment was performed to evaluate vasorelaxation. Western blot was used to measure the expression of PI3K, Akt, phosphorylated Akt (p-Akt) and eNOS proteins in the abdominal aorta. Further, quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to measure the relative levels of mRNA expression for PI3K, Akt and eNOS in the abdominal aorta. RESULTS: EA significantly reduced the systolic BP (SBP) and diastolic BP (DBP) (P < 0.05). HE staining showed that EA improved the morphology of the vascular endothelium to some extent. Results of ELISA indicated that higher concentrations of ghrelin and NO, and lower concentrations of ET-1 and TXA2 were presented in the EA group (P < 0.05). The isolated thoracic aortic ring experiment demonstrated that the vasodilation capacity of the thoracic aorta increased in the EA group. Results of Western blot and qRT-PCR showed that EA increased the abundance of PI3K, p-Akt/Akt and eNOS proteins, as well as expression levels of PI3K, Akt and eNOS mRNAs (P < 0.05). In the EA + G group, SBP and DBP decreased (P < 0.05), ghrelin concentrations increased (P < 0.05), and the concentrations of ET-1 and TXA2 decreased (P < 0.05), relative to the EA group. In addition, the levels of PI3K and eNOS proteins, the p-Akt/Akt ratio, and the expression of PI3K, Akt and eNOS mRNAs increased significantly in the EA + G group (P < 0.05), while PF04628935 reversed these effects. CONCLUSION: EA effectively reduced BP and protected the vascular endothelium, and these effects may be linked to promoting the release of ghrelin and activation of the PI3K/Akt/eNOS signaling pathway.

Triterpenoid saponins from Ilex pubescens promote blood circulation in blood stasis syndrome by regulating sphingolipid metabolism and the PI3K/AKT/eNOS signaling pathway.

BACKGROUND: Blood stasis syndrome (BSS) is a severe disorder involving disturbances in glycerophosphocholine metabolism. Ilex pubescens (IP) can regulate the levels of lipids, such as lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE); however, the main active constituent of IP and its corresponding mechanism in BSS treatment are still unclear. PURPOSE: To explore the mechanisms by which triterpenoid saponins of IP (IPTS) promote blood circulation using system pharmacology-based approaches. METHODS: Sprague-Dawley (SD) rat BSS model was prepared by oral administration of IPTS for 7 days followed by adrenaline hydrochloride injection before immersion in ice water. Coagulation parameters in plasma and thromboxane B2 (TXB2), endothelin (ET) and 6-keto-PGF1α in serum were measured. The possible influence on abdominal aortas was evaluated by histopathology assessment. Human vein endothelial cells (HUVECs) were incubated with ox-LDL, and the effects of IPTS on cell viability and LDH release were investigated. UPLC-QTOF-MS/MS was used for metabolic profile analysis of lipid-soluble components in rat plasma and intracellular metabolites in HUVECs. Network pharmacology was used to predict the relevant targets and model pathways of BSS and the main components of IPTS. Molecular docking, molecular dynamics (MD) simulation and biochemical assays were used to predict molecular interactions between the active components of IPTS and target proteins. RT-PCR was used to detect the mRNA level of target proteins. Western blotting and immunohistochemistry (IHC) were used to verify the mechanisms by which IPTS promotes blood circulation in BSS. RESULTS: IPTS improved blood biochemical function in the process of BSS and played a role in vascular protection and maintenance of the normal morphology of blood vessels. Furthermore, metabolite pathways involved in steroid biosynthesis and sphingolipid metabolism were significantly perturbed. Both metabolomics analysis and network pharmacology results showed that IPTS ameliorates vascular injury and that lipid accumulation may be mediated by PI3K/AKT signaling pathway activation. MD simulation and enzyme inhibitory activity results suggested that the main components of IPTS can form stable complexes with PI3K, AKT and eNOS and that the complexes have significant binding affinity. PI3K, AKT, p-AKT, and eNOS mRNA and protein levels were considerably elevated in the IPTS-treated group. Thus, IPTS protects the vasculature by regulating the PI3K/AKT signaling pathway, activating eNOS and increasing the release of NO. CONCLUSION: A possible mechanism by which IPTS prevents BSS is proposed: IPTS can promote blood circulation by modulating sphingolipid metabolism and activating the PI3K/AKT/eNOS signaling pathways.

Influence of electroacupuncture on ghrelin and the phosphoinositide 3-kinase/protein kinase B/endothelial nitric oxide synthase signaling pathway in spontaneously hypertensive rats / 中西医结合学报

OBJECTIVE@#To investigate the influence of electroacupuncture (EA) on ghrelin and the phosphoinositide 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling pathway in spontaneously hypertensive rats (SHRs).@*METHODS@#Eight Wistar-Kyoto rats were used as the healthy blood pressure (BP) control (normal group), and 32 SHRs were randomized into model group, EA group, EA plus ghrelin group (EA + G group), and EA plus PF04628935 group (a potent ghrelin receptor blocker; EA + P group) using a random number table. Rats in the normal group and model group did not receive treatment, but were immobilized for 20 min per day, 5 times a week, for 4 continuous weeks. SHRs in the EA group, EA + G group and EA + P group were immobilized and given EA treatment in 20 min sessions, 5 times per week, for 4 weeks. Additionally, 1 h before EA, SHRs in the EA + G group and EA + P group were intraperitoneally injected with ghrelin or PF04628935, respectively, for 4 weeks. The tail-cuff method was used to measure BP. After the 4-week intervention, the rats were sacrificed by cervical dislocation, and pathological morphology of the abdominal aorta was observed using hematoxylin-eosin (HE) staining. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of ghrelin, nitric oxide (NO), endothelin-1 (ET-1) and thromboxane A2 (TXA2) in the serum. Isolated thoracic aortic ring experiment was performed to evaluate vasorelaxation. Western blot was used to measure the expression of PI3K, Akt, phosphorylated Akt (p-Akt) and eNOS proteins in the abdominal aorta. Further, quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to measure the relative levels of mRNA expression for PI3K, Akt and eNOS in the abdominal aorta.@*RESULTS@#EA significantly reduced the systolic BP (SBP) and diastolic BP (DBP) (P < 0.05). HE staining showed that EA improved the morphology of the vascular endothelium to some extent. Results of ELISA indicated that higher concentrations of ghrelin and NO, and lower concentrations of ET-1 and TXA2 were presented in the EA group (P < 0.05). The isolated thoracic aortic ring experiment demonstrated that the vasodilation capacity of the thoracic aorta increased in the EA group. Results of Western blot and qRT-PCR showed that EA increased the abundance of PI3K, p-Akt/Akt and eNOS proteins, as well as expression levels of PI3K, Akt and eNOS mRNAs (P < 0.05). In the EA + G group, SBP and DBP decreased (P < 0.05), ghrelin concentrations increased (P < 0.05), and the concentrations of ET-1 and TXA2 decreased (P < 0.05), relative to the EA group. In addition, the levels of PI3K and eNOS proteins, the p-Akt/Akt ratio, and the expression of PI3K, Akt and eNOS mRNAs increased significantly in the EA + G group (P < 0.05), while PF04628935 reversed these effects.@*CONCLUSION@#EA effectively reduced BP and protected the vascular endothelium, and these effects may be linked to promoting the release of ghrelin and activation of the PI3K/Akt/eNOS signaling pathway.

Lancemaside A, a major triterpene saponin of Codonopsis lanceolata enhances regulation of nitric oxide synthesis via eNOS activation.

BACKGROUND: Many studies on the effect of saponin-rich Codonopsis lanceolata as a bioactive source for improving physical health have been performed. C. lanceolata contains triterpenoid saponins, including lancemasides. These saponins are known to be particularly involved in the regulation of blood pressure or hypertension. This study investigated whether lancemaside A (LA), a major triterpenoid saponin from C. lanceolata, regulates nitric oxide (NO) production via the activation of endothelial NO synthase (eNOS) in human umbilical vein endothelial cells. METHODS: Upon separation with petroleum ether, ethyl acetate, and n-butanol, LA was found to be abundant in the n-butanol-soluble portion. For further purification of LA, HPLC was performed to collect fraction, and LA was identified using analysis of LC/MSMS and 13C-NMR values. In in vitro, the effects of LA on NO release mechanism in HUVECs were investigated by Griess assay, quantitative real-time reverse-transcription PCR, and Western blotting. RESULTS: Our results showed that NO production was efficiently improved by treatment with LA in a dose-dependent manner. In addition, the LA treatment resulted in extensive recovery of the NO production suppressed by the eNOS inhibitor, L-NAME, compared with that in the control group. Additionally, the level of eNOS mRNA was increased by this treatment in a dose-dependent manner. These results suggested that LA is an inducer of NO synthesis via eNOS mRNA expression. Also, the study indicated that LA is involved in activating the PI3K/Akt/eNOS signaling pathway. CONCLUSION: These results suggested that LA is an inducer of NO synthesis via eNOS mRNA expression. Also, the study indicated that LA is involved in activating the PI3K/Akt/eNOS signaling pathway. These findings suggest the value of using LA as a component of functional foods and natural pharmaceuticals.

[Effects of PI3K/Akt-eNOS signaling pathway on total flavones in Clematis filamentosa post-conditioning alleviated of myocardial ischemia-reperfusion injury in rats].

The aim of this paper was to study the effect of total flavones of Clematis filamentosa Dunn(TFCD) post-conditioning against myocardial ischemia-reperfusion injury (MIRI) and the role of PI3K/Akt-eNOS signaling pathway. Forty male SD rats were divided randomly into five groups: Sham group, model group (I/R), TFCD post-conditioning group (TFCD), TFCD post-condition-ing+LY294002 (a PI3K/Akt signaling pathway inhibitor) group (TFCD+LY), and LY294002 group (LY). At the end of reperfusion, hemodynamic parameters were recorded, morphology changes of myocardial tissue were evaluated by using HE staining, and myocardial infarct size were observed, blood samples were obtained to determine plasma activation of lactate dehydrogenase (LDH), creatine kinase (CK) nitric oxide (NO), endothelial nitric oxide synthase (eNOS), superoxide dismutase (SOD), maleic dialdehyde (MDA) and glutathione peroxidase (GSH-Px). The expressions of Akt, p-Akt, eNOS and p-eNOS proteins were assessed by using Western blot, and eNOS and inducible nitric oxide synthase (iNOS) mRNA was measured by RT-PCR. The results showed that, compared with the model group, TFCD post-conditioning remarkably improved hemodynamics function and myocardial structure, reduced myocardial infarct size and enhanced the contents of NO, eNOS, SOD and GSH-Px, and decreased the contents of LDH, CK and MDA, increased the levels of phosphorylation of Akt and eNOS protein expression, eNOS and iNOS mRNA expression significantly(P＜0.05 or P＜0.01). These effects were inhibited by LY294002, a blocker of PI3K/Akt signaling pathway. The above experiments indicated that TFCD post-conditioning could significantly reduce MIRI in rats, the mechanism of which may be associated with increasing antioxidation, scavenging oxygen free radicals, regulating NO generation and activating PI3K/Akt-eNOS signaling pathway.