Formononetin upregulates nitric oxide synthase in arterial endothelium through estrogen receptors and MAPK pathways

Formononetin alleviates no reflow after myocardial ischemia-reperfusion via modulation of gut microbiota to inhibit inflammation

Gut microflora plays an important role in relieving myocardial no-reflow (NR), formononetin (FMN) has potential effects on NR, however, the relationship between this effect and gut microflora remains unclear. This study aimed to evaluate the role of FMN in alleviating NR by regulating gut microflora. We used a myocardial NR rat model to confirm the effect and mechanism of action of FMN in alleviating NR. The rats were randomly divided into sham operation group (Sham), NR group, FMN group and sodium nitroprusside (SNP) group. Thioflavin S staining, Hematoxylin Eosin (HE), myocardial enzyme activity, ultrasonic cardiogram and RT-PCR detection showed that FMN could effectively reduce inflammatory cell infiltration, NR and ischemic area, improve cardiac structure and function and reduce TNF-α and NF-κB gene expression in NR rats. The results of 16S rRNA high-throughput sequencing showed that FMN could increase the abundance of anti-inflammatory bacteria such as Ligilactobacillus, Coprococcus, Blautia and Muribaculaceae and decrease the abundance of pro-inflammatory bacteria such as Treponema in Spirochaetota and Campylobacterota. The correlation between the differential bacteria in the gut microflora(anti-inflammatory bacteria and pro-inflammatory bacteria) and TNF-α and NF-κB, showed that they had a strong correlation. Therefore, the anti-NR mechanism of FMN may be related to increasing the abundance of anti-inflammatory bacteria and reducing the abundance of pro-inflammatory bacteria to inhibit inflammation. This study provides innovative mechanistic insights into the relationship between gut microbiota and myocardial protection, suggesting potential strategy for future treatment of NR.

Integrated metabolomics and transcriptomics analysis reveals the mechanism of Tangbi capsule for diabetic lower extremities arterial disease

Objective

Tangbi capsule (TBC) is a traditional Chinese medicine prescription, which has the potential to improve the vascular insufficiency of lower extremities and limb numbness in diabetes. However, the potential mechanism remains unknown. This study aims to investigate the pharmacological effects and mechanism of TBC on rats with diabetic lower extremities arterial disease (LEAD).

Methods

The mechanism of TBC on diabetic LEAD was investigated through metabolomics and transcriptomics analysis, and the main components of TBC were determined by mass spectrometry. The efficacy and mechanism of TBC on diabetic LEAD rats were investigated through in vitro experiments, histopathology, blood flow monitoring, western blot, and real-time polymerase chain reaction.

Results

Mass spectrometry analysis identified 31 active chemical components in TBC including (2R)-2,3-Dihydroxypropanoic acid, catechin, citric acid, miquelianin, carminic acid, salicylic acid, formononetin, etc. In vitro analysis showed that TBC could reduce endothelial cell apoptosis and promote angiogenesis. Histopathological analysis showed that TBC led to an obvious improvement in diabetic LEAD as it improved fibrous tissue proliferation and reduced arterial wall thickening. In addition, TBC could significantly increase the expression levels of HIF-1α, eNOS, and VEGFA proteins and genes while reducing that of calpain-1 and TGF-β, suggesting that TBC can repair vascular injury. Compared with the model group, there were 47 differentially expressed genes in the whole blood of TBC groups, with 25 genes upregulated and 22 downregulated. Eighty-seven altered metabolites were identified from the serum samples. Combining the changes in differentially expressed genes and metabolites, we found that TBC could regulate arginine biosynthesis, phenylalanine metabolism, pyrimidine metabolism, arachidonic acid metabolism, pyrimidine metabolism, arachidonic acid metabolism, nucleotide metabolism, vitamin B6 metabolism and other metabolic pathways related to angiogenesis, immune-inflammatory response, and cell growth to improve diabetic LEAD.

Conclusion

TBC improved vascular endothelial injury, apoptosis, lipid accumulation, liver and kidney function, and restored blood flow in the lower extremities of diabetic LEAD rats. The mechanism of TBC in the treatment of diabetic LEAD may be related to the modulation of inflammatory immunity, lipid metabolism, and amino acid metabolism. This study presented preliminary evidence to guide the use of TBC as a therapy option for diabetic LEAD.

Estrogenic flavonoids and their molecular mechanisms of action

Flavonoids are a major group of phytoestrogens associated with physiological effects, and ecological and social impacts. Although the estrogenic activity of flavonoids was reported by researchers in the fields of medical, environmental and food studies, their molecular mechanisms of action have not been comprehensively reviewed. The estrogenic activity of the respective classes of flavonoids, anthocyanidins/anthocyanins, 2-arylbenzofurans/3-arylcoumarins/α-methyldeoxybenzoins, aurones/chalcones/dihydrochalcones, coumaronochromones, coumestans, flavans/flavan-3-ols/flavan-4-ols, flavanones/dihydroflavonols, flavones/flavonols, homoisoflavonoids, isoflavans, isoflavanones, isoflavenes, isoflavones, neoflavonoids, oligoflavonoids, pterocarpans/pterocarpenes, and rotenone/rotenoids, was summarized through a comprehensive literature search, and their structure-activity relationship, biological activities, signaling pathways, and applications were discussed. Although the respective classes of flavonoids contained at least one chemical mimicking estrogen, the mechanisms varied, such as those with estrogenic, anti-estrogenic, non-estrogenic, and biphasic activities, and additional activities through crosstalk/bypassing, which exert biological activities through cell signaling pathways. Such mechanistic variations of estrogen action are not limited to flavonoids and are observed among other broad categories of chemicals, thus this group of chemicals can be termed as the "estrogenome". This review article focuses on the connection of estrogen action mainly between the outer and the inner environments, which represent variations of chemicals and biological activities/signaling pathways, respectively, and form the basis to understand their applications. The applications of chemicals will markedly progress due to emerging technologies, such as artificial intelligence for precision medicine, which is also true of the study of the estrogenome including estrogenic flavonoids.

Estrogen Receptor Subtypes Elicit a Distinct Gene Expression Profile of Endothelial-Derived Factors Implicated in Atherosclerotic Plaque Vulnerability

In the presence of established atherosclerosis, estrogens are potentially harmful. MMP-2 and MMP-9, their inhibitors (TIMP-2 and TIMP-1), RANK, RANKL, OPG, MCP-1, lysyl oxidase (LOX), PDGF-β, and ADAMTS-4 play critical roles in plaque instability/rupture. We aimed to investigate (i) the effect of estradiol on the expression of the abovementioned molecules in endothelial cells, (ii) which type(s) of estrogen receptors mediate these effects, and (iii) the role of p21 in the estrogen-mediated regulation of the aforementioned factors. Human aortic endothelial cells (HAECs) were cultured with estradiol in the presence or absence of TNF-α. The expression of the aforementioned molecules was assessed by qRT-PCR and ELISA. Zymography was also performed. The experiments were repeated in either ERα- or ERβ-transfected HAECs and after silencing p21. HAECs expressed only the GPR-30 estrogen receptor. Estradiol, at low concentrations, decreased MMP-2 activity by 15-fold, increased LOX expression by 2-fold via GPR-30, and reduced MCP-1 expression by 3.5-fold via ERβ. The overexpression of ERα increased MCP-1 mRNA expression by 2.5-fold. In a low-grade inflammation state, lower concentrations of estradiol induced the mRNA expression of MCP-1 (3.4-fold) and MMP-9 (7.5-fold) and increased the activity of MMP-2 (1.7-fold) via GPR-30. Moreover, p21 silencing resulted in equivocal effects on the expression of the abovementioned molecules. Estradiol induced different effects regarding atherogenic plaque instability through different ERs. The balance of the expression of the various ER subtypes may play an important role in the paradoxical characterization of estrogens as both beneficial and harmful.

In utero hypoxia attenuated acetylcholine-mediated vasodilatation via CHRM3/p-NOS3 in fetal sheep MCA: role of ROS/ERK1/2

Hypoxia can lead to adult middle cerebral artery (MCA) dysfunction and increase the risk of cerebrovascular diseases. It is largely unknown whether intrauterine hypoxia affects fetal MCA vasodilatation. This study investigated the effects and mechanisms of intrauterine hypoxia on fetal MCA vasodilatation. Near-term fetal sheep were exposed to intrauterine hypoxia. Human umbilical vein endothelial cells (HUVECs) were exposed to hypoxia in cellular experiments. Vascular tone measurement, molecular analysis, and transmission electron microscope (TEM) were utilized to determine vascular functions, tissue anatomy, and molecular pathways in fetal MCA. In fetal MCA, acetylcholine (ACh) induced reliable relaxation, which was markedly attenuated by intrauterine hypoxia. Atropine, P-F-HHSiD, L-NAME, and u0126 blocked most ACh-mediated dilation, while AF-DX 116 and tropicamide partially inhibited the dilation. Indomethacin and SB203580 did not significantly change ACh-mediated dilation. Tempol and PS-341 could restore the attenuated ACh-mediated vasodilatation following intrauterine hypoxia. The mRNA expression levels of CHRM2 and CHRM3 and the protein levels of CHRM3, p-NOS3, SOD2, ERK1/2, p-ERK1/2, MAPK14, and p-MAPK14 were significantly reduced by intrauterine hypoxia. The dihydroethidium assay showed that the production of ROS was increased under intrauterine hypoxia. TEM analysis revealed endothelial cells damaged by intrauterine hypoxia. In HUVECs, hypoxia increased ROS formation and decreased the expression of CHRM3, p-NOS3, SOD1, SOD2, SOD3, ERK1/2, p-ERK1/2, and p-MAPK14, while tempol and PS-341 potentiated p-NOS3 protein expression. In conclusion, in utero hypoxia reduced ACh-mediated vasodilatation in ovine MCA predominantly via decreased CHRM3 and p-NOS3, and the decreased NOS3 bioactivities might be attributed to ROS and ERK1/2.

Formononetin regulates endothelial nitric oxide synthase to protect vascular endothelium in deep vein thrombosis rats

OBJECTIVE

Formononetin is a bioactive isoflavone that has numerous medicinal benefits. We explored the feasibility and its mechanism of formononetin on treating acute deep vein thrombosis (DVT) in rats.

MATERIALS AND METHODS

Inferior vena cava (IVC) stenosis was performed to establish the DVT rat model. First, different doses of formononetin were used to observe the feasibility of formononetin on treating DVT. In sham and DVT groups, rats were orally treated with vehicle. In the remaining groups, formononetin (10 mg/kg, 20 mg/kg, and 40 mg/kg) was orally treated once a day for 7 days at 24 h after IVC. After 7 days, the levels of thrombosis and inflammation related factors in plasma were measured. The expression of endothelial nitric oxide synthase (eNOS) was analyzed by western blot and immunofluorescence. Molecular docking was used to evaluate the interaction between the formononetin and eNOS. Further, the NOS inhibitor (L-NAME) was used to explore the mechanism of formononetin for DVT.

RESULT

After treatment with formononetin, the average weights of thrombosis were decreased, and the levels of thrombosis and inflammation related factors were also significantly decreased. Additionally, phosphorylation of eNOS was increased with the formononetin administration. There is a good activity of formononetin to eNOS (total score = -6.8). However, the effects of 40 mg/kg formononetin were concealed by the NOS inhibitor (L-NAME).

CONCLUSION

Formononetin reduces vascular endothelium injury induced by DVT through increasing eNOS in rats, which provides a potential drug for treatment of venous thrombosis.

The Vascular Effects of Isolated Isoflavones-A Focus on the Determinants of Blood Pressure Regulation

Isoflavones are phytoestrogen compounds with important biological activities, including improvement of cardiovascular health. This activity is most evident in populations with a high isoflavone dietary intake, essentially from soybean-based products. The major isoflavones known to display the most important cardiovascular effects are genistein, daidzein, glycitein, formononetin, and biochanin A, although the closely related metabolite equol is also relevant. Most clinical studies have been focused on the impact of dietary intake or supplementation with mixtures of compounds, with only a few addressing the effect of isolated compounds. This paper reviews the main actions of isolated isoflavones on the vasculature, with particular focus given to their effect on the determinants of blood pressure regulation. Isoflavones exert vasorelaxation due to a multitude of pathways in different vascular beds. They can act in the endothelium to potentiate the release of NO and endothelium-derived hyperpolarization factors. In the vascular smooth muscle, isoflavones modulate calcium and potassium channels, leading to hyperpolarization and relaxation. Some of these effects are influenced by the binding of isoflavones to estrogen receptors and to the inhibition of specific kinase enzymes. The vasorelaxation effects of isoflavones are mostly obtained with plasma concentrations in the micromolar range, which are only attained through supplementation. This paper highlights isolated isoflavones as potentially suitable alternatives to soy-based foodstuffs and supplements and which could enlarge the current therapeutic arsenal. Nonetheless, more studies are needed to better establish their safety profile and elect the most useful applications.

Potential Anticancer Properties and Mechanisms of Action of Formononetin

Nature, a vast reservoir of pharmacologically active molecules, has been most promising source of drug leads for the cure of various pathological conditions. Formononetin is one of the bioactive isoflavones isolated from different plants mainly from Trifolium pratense, Glycine max, Sophora flavescens, Pycnanthus angolensis, and Astragalus membranaceus. Formononetin has been well-documented for its anti-inflammatory, anticancer, and antioxidant properties. Recently anticancer activity of formononetin is widely studied. This review aims to highlight the pharmacological potential of formononetin, thus providing an insight of its status in cancer therapeutics. Formononetin fights progression of cancer via inducing apoptosis, arresting cell cycle, and halting metastasis via targeting various pathways which are generally modulated in several cancers. Although reported data acclaims various biological properties of formononetin, further experimentation on mechanism of its action, medicinal chemistry studies, and preclinical investigations are surely needed to figure out full array of its pharmacological and biological potential.

Formononetin ameliorates high glucose‑induced endothelial dysfunction by inhibiting the JAK/STAT signaling pathway

High glucose‑induced endothelial Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling is associated with the development and progression of the vascular complications of diabetes. The present study aimed to investigate whether formononetin, a biologically active compound isolated from Astragalus membranaceus (Fisch.) Bge, was able to regulate the JAK/STAT signaling pathway, improving endothelial function. In the present study, formononetin was identified to act as a JAK2 inhibitor, similarly to tyrphostin AG 490 (AG490), by significantly inhibiting the phosphorylation and the mRNA expression levels of JAK2 and STAT in HUVECs exposed to high glucose levels. In addition, formononetin and AG490 improved the viability of HUVECs and inhibited the protein expression levels of caspase‑3. Furthermore, formononetin and AG490 attenuated the inflammatory response in HUVECs by downregulating the protein and mRNA expression levels of interleukin (IL)‑1β and intercellular adhesion molecule 1 (ICAM‑1). Formononetin and AG490 also restored nitric oxide (NO) synthesis in HUVECs. Notably, formononetin was able to reverse the abnormal levels of phosphorylated (p)‑JAK2, p‑STAT3, IL‑1β, ICAM‑1 and NO induced by cotreatment with high glucose and IL‑6, an agonist of the JAK/STAT signaling pathway. Additionally, the present results suggested that formononetin restored phenylephrine‑mediated contraction and acetylcholine‑induced relaxation in aortic tissues of rats fed a high‑glucose diet, in a dose‑dependent manner. Collectively, formononetin could improve endothelial function under glucose stress in vivo and in vitro, suggesting that formononetin may represent a novel potential therapeutic compound to treat diabetic vascular complications.

Soy Isoflavone Improved Female Sexual Dysfunction of Mice Via Endothelial Nitric Oxide Synthase Pathway

Introduction

Female sexual dysfunction (FSD) is a common endocrine disease that impairs the quality of life for many women. The existing therapy strategies still have many disadvantages. It is necessary to explore new pharmacologic treatments that are effective and safe.

Aim

The aim of this study was to explore the effects of soy isoflavone (SI) on FSD in mice and the underlying mechanisms.

Methods and Main Outcome Measures

Laser Doppler flowmetry was used to determine vaginal blood flow. Serum hormone levels and histologic changes of the vagina were analyzed by enzyme-linked immunosorbent assay (ELISA) and by hematoxylin and eosin (H&E) and Masson’s trichome staining. The mRNA and protein expression of endothelial nitric oxide synthase (eNOS) was then evaluated by quantitative real-time polymerase chain reaction and western blot assays.

Results

Vaginal blood flow was found to be remarkably lower in adult mice, and SI was shown to increase vaginal blood flow in a dose-dependent manner (P < .05). The results of ELISA and H&E and Masson’s trichome staining suggest that SI had a positive effect on FSD, as evidenced by the levels of hormones in serum and histologic changes of the vagina, which changed consistently. In addition, the level of eNOS was positively correlated with the concentration of SI, and eNOS inhibitor was able to reverse the improvement in sexual function induced by SI.

Conclusion

Our study demonstrated that SI could improve sexual function by upregulating the eNOS pathway. Therefore, SI might serve as a promising candidate for the treatment of sexual dysfunction.

Zhang J, Zhu Y, Pan L, et al. Soy Isoflavone Improved Female Sexual Dysfunction of Mice Via Endothelial Nitric Oxide Synthase Pathway. Sex Med 2019; 7:345–351.

G protein-coupled estrogen receptor activation improves contractile and diastolic functions in rat renal interlobular artery to protect against renal ischemia reperfusion injury

OBJECTIVE

This work aimed to investigate whether G protein-coupled estrogen receptor (GPER) can improve the renal interlobular artery vascular function by increasing the NO content, thereby protecting against renal ischemia-reperfusion (IR) injury.

METHODS

This study classified ovariectomised (OVX) female Sprague-Dawley rats into OVX, OVX + IR, OVX + IR + G1 (the GPER agonist G1), OVX + IR + G1+G15 (GPER blocker) and OVX + IR + G1+L-NAME (eNOS blocker) groups. Enzyme-linked immunosorbent assay was performed to detect the estrogen levels in the body and eliminate interference from endogenous estrogens. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) and HE staining, renal function test and Paller scoring were performed to identify the successful model and detect the degree of renal and renal interlobular arteries injury. The in vitro microvascular pressure diameter measurement technique was used to detect the contraction and diastolic activities of the renal interlobular arteries in each group. Immunofluorescence technique was used to observe the localisation and expression levels of GPER and eNOS in renal interlobular arteries. The GPER and eNOS protein expression levels in each group were detected by Western blot. The NO content in the serum of each group was detected by the nitrate reductase method.

RESULT

After OVX, the estrogen level in the body decreased significantly (P < 0.01), and TUNEL staining showed a significant increase in the degree of renal tubular epithelial cell apoptosis in the IR group. Serum creatinine (SCr) and blood urea nitrogen (BUN) levels were significantly increased in the IR group (P < 0.01), and the Paller score showed significantly increased kidney damage. When performing drug treatment, the G1 intervention group significantly decreased serum BUN and SCr levels after IR injury (P < 0.01). The Paller score showed significantly decreased the degree of renal injury (P < 0.01). After IR, the renal interlobular artery contraction rate and systolic velocity of blood vessels were significantly decreased (P < 0.01). The G1 intervention group significantly restored contraction rate and systolic velocity of blood vessels (P < 0.01), and G15 and L-NAME partially reversed this effect (P < 0.01). Immunofluorescence technique showed that GPER was expressed in renal interlobular artery smooth muscle and endothelial cells. After IR injury, the GPER protein expression increased, and the eNOS protein expression decreased significantly (P < 0.01). Western blot showed that after IR injury, the GPER protein expression increased, and the eNOS protein expression decreased significantly. After G1 intervention, the GPER content did not change, and the eNOS content increased significantly (P < 0.01). After ischemia and reperfusion, the serum NO content decreased significantly, but it increased after G1 intervention. G15 and L-NAME reversed the effects of G1 to varying degrees (both at P < 0.01).

CONCLUSION

GPER may improve the renal interlobular artery vascular function by increasing the NO content, thereby protecting against renal IR injury.

Formononetin induces vasorelaxation in rat thoracic aorta via regulation of the PI3K/PTEN/Akt signaling pathway

Background

Formononetin (FMN) is an isoflavone that produces arterial vasodilation. However, the underlying molecular mechanisms are unclear.

Purpose

The purpose of this study was to explore the vasorelaxant effect and the potential mechanism of FMN in vascular endothelium in isolated rat aorta.

Methods

The thoracic aortas of Sprague Dawley rats were isolated to test the arterial reactivity in the presence of FMN with or without inhibitors. Bioinformatics analyses, including a Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine and molecular docking methods, were performed to predict therapeutic targets responsible for the vascular protection produced by FMN. We used rat aortic endothelial cells (RAOECs) as an in vitro model to verify the potential mechanism through molecular biological analyses. The production of nitric oxide (NO) metabolites were evaluated via an NO assay kit according to the manufacturer's instruction. The mRNA expression of eNOS was analyzed by polymerase chain reaction, and the protein levels of PTEN, phosphorylated Akt, and eNOS were measured by Western blot.

Results

We found that FMN dilated rat aortic rings in a concentration-dependent manner, which was reduced by endothelium denudation and eNOS inhibition. The bioinformatics analyses indicated that FMN activity was associated with the PI3K/PTEN/Akt signaling pathway. Molecular biological studies demonstrated that FMN significantly elevated the levels of NO and eNOS mRNA and markedly increased the protein expression of phosphorylated Akt and eNOS in RAOECs, and decreased PTEN compared with a dimethyl sulfoxide group.

Conclusion

FMN performs vasorelaxation of the thoracic aorta through activating the PI3K/PTEN/Akt signaling pathway.

Formononetin ameliorates mast cell-mediated allergic inflammation via inhibition of histamine release and production of pro-inflammatory cytokines

Various allergic diseases cause allergic inflammation, which is mediated by mast cells. The current study investigated the anti-allergic inflammatory effects of formononetin and its mechanism of action in vitro using mast cells. Levels of histamine and pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6, were measured to assess the effects of formononetin on allergic inflammation. The activation of intracellular calcium and nuclear factor (NF)-κB, as well as the activity of caspase-1, were assessed to determine the mechanism of action. It was determined that difference concentrations of formononetin (0.1, 1 and 10 µM) suppressed histamine release and secretion of TNF-α, IL-1β and IL-6. Further investigations indicated that the effects of formononetin were associated with a reduction of intracellular calcium, suppression of NF-κB activation and upstream IκKα phosphorylation and inhibition of caspase-1 activity. Therefore, the results of the current study demonstrated that formononetin ameliorated mast cell-mediated allergic inflammation.