Activation of estrogen receptor α inhibits TLR4 signaling in macrophages and alleviates the instability of atherosclerotic plaques in the postmenopausal stage.

Acute cardiovascular events increase significantly in postmenopausal women. The relationship between estrogen receptor (ER) and plaque stability in the postmenopausal stage remains to be elucidated. We aimed to explore whether ERα activation improves plaque instability in the postmenopausal stage. Here, we report that postmenopausal women showed increased macrophage activation and plaque instability with increased MCP-1, MMP9, TLR4, MYD88 and NF-κB p65 and decreased ERα and TIMP1 expression in the vascular endothelium. Moreover, ovariectomy in LDLR-/- mice resulted in a significant increase in plaque area and necrotic core area, as well as a significant decrease in collagen content and an increase in macrophage accumulation in the artery. Ovariectomy also reduced serum estrogen levels and ERα expression and upregulated TLR4 and MMP9 expression in arteries in LDLR-/- mice. Estrogen or phytoestrogen therapy upregulated the expression level of ERα in ovariectomized mice and increased plaque stability by inhibiting macrophage accumulation and TLR4 signaling. In vitro, LPS incubation of RAW264.7 cells resulted in a significant decrease in ERα and TIMP1 expression and an increase in TLR4 activation, and estrogen or phytoestrogen treatment increased ERα and TIMP1 expression and inhibited TLR4 activation and MMP9 expression in LPS-treated RAW264.7 cells. Compared to control siRNA transfected RAW264.7 cells, TLR4 siRNA promoted TIMP1 expression in RAW264.7 cells with LPS incubation, but did not affect ERα expression in RAW264.7 cells with or without LPS treatment. The ERα inhibitor MPP abolished the regulatory effect of estrogen or phytoestrogen on LPS-induced RAW264.7 cells. In conclusion, the present study demonstrates that decreased ERα expression promotes macrophage infiltration and plaque instability in the postmenopausal stage, and activation of ERα in the postmenopausal stage alleviates atherosclerotic plaque instability by inhibiting TLR4 signaling and macrophage-related inflammation.

Alisol B 23-acetate adjusts bile acid metabolisim via hepatic FXR-BSEP signaling activation to alleviate atherosclerosis.

BACKGROUND: Postmenopausal women have a high incidence of atherosclerosis. Phytosterols have been shown to have cholesterol-lowering properties. Alisa B 23-acetate (AB23A) is a biologically active plant sterol isolated from Chinese herbal medicine Alisma. However, the atherosclerosis effect of AB23A after menopause and its possible mechanism have not been reported yet. PURPOSE: To explore whether AB23A can prevent atherosclerosis by regulating farnesoid X receptor and subsequently increasing fecal bile acid and cholesterol excretion to reduce plasma cholesterol levels. METHODS: Aortic samples from premenopausal and postmenopausal women with ascending aortic arteriosclerosis were analyzed, and bilateral ovariectomized (OVX) female LDLR-/- mice and free fatty acid (FFA)-treated L02 cells were used to analyze the effect of AB23A supplementation therapy. RESULTS: AB23A increased fecal cholesterol and bile acids (BAs) excretion dependent on activation of hepatic farnesoid X receptor (FXR) in ovariectomized mice. AB23A inhibited hepatic cholesterol 7α-hydroxylase (CYP7A1) and sterol 12α-hydroxylase (CYP8B1) via inducing small heterodimer partner (SHP) expression. On the other hand, AB23A increased the level of hepatic chenodeoxycholic acid (CDCA), and activated the hepatic BSEP signaling. The activation of hepatic FXR-BSEP signaling by AB23A in ovariectomized mice was accompanied by the reduction of liver cholesterol, hepatic lipolysis, and bile acids efflux, and reduced the damage of atherosclerosis. In vitro, AB23A fixed abnormal lipid metabolism in L02 cells and increased the expression of FXR, BSEP and SHP. Moreover, the inhibition and silencing of FXR canceled the regulation of BSEP by AB23A in L02 cells. CONCLUSION: Our results shed light into the mechanisms behind the cholesterol-lowering of AB23A, and increasing FXR-BSEP signaling by AB23A may be a potential postmenopausal atherosclerosis therapy.

Liuwei Dihuang formula protect endothelial cells from apoptosis by up-regulating expression of estrogen receptor-α.

OBJECTIVE: To evaluate the efficacy of Liuwei Dihuang formula ( LWDHF) on endothelial cells, and to study the mechanism behind the action of modulating expression of estrogen receptors. METHODS: Hydrogen peroxide (H2O2) was applied to induce the apoptosis of human umbilical vein endothelial cells (HUVECs). The concentration of nitric oxide (NO), endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS) were measured by assay kits. Western blot and real-time polymerase chain reaction (RT-PCR) were used to detect the expression of iNOS, eNOS, b-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), estrogen receptor (ER) α and ERß. Also, small interfering RNA (siRNA) was involved to confirm whether the protective effects of LWDHF was medicated by ERs. In vivo, the female rats were ovariectomized to establish postmenopausal vascular injury model. Then the model rats were divided into three groups and treated with saline, estradiol and LWDHF respectively. The concentration of NO and NOS in serum were measured by assay kits, and the expression of Bax, Bcl-2, ERα and ERß were detected by western blot and immunohistochemistry. RESULTS: In vitro study, LWDHF significantly protected HUVECs from H2O2-induced apoptosis, with the increase of Bcl-2 and the decrease of Bax. The treatment with LWDHF inhibited concentration of NO and iNOS, and upregulated the expression of eNOS, ERα and ERß. In addition, ERα siRNA could block the protective effects of LWDHF, while ERß siRNA showed little influence. In vivo, the treatment with LWDHF suppressed the vascular injury and reduced the level of NO and NOS. LWDHF increased the expression of Bcl-2, ERα and ERß, as well as inhibiting the Bax expression. CONCLUSION: LWDHF could improve endothelial function and protect HUVECs from apoptosis via increasing the expression of ERα.

Liuwei Dihuang prevents postmenopausal atherosclerosis and endothelial cell apoptosis via inhibiting DNMT1-medicated ERα methylation.

ETHNOPHARMACOLOGICAL RELEVANCE: The classical and traditional Chinese medicine prescription, Liuwei Dihuang (LWDH), has been commonly used to treat the menopausal syndrome. It has been reported that LWDH could improve estrogen receptor α (ERα) expression to prevent atherosclerosis (AS), while the mechanism of LWDH on regulating ERα expression was still unknown. AIM OF THE STUDY: To reveal the mechanism of LWDH on regulating the ERα expression. MATERIALS AND METHODS: The protective effect of LWDH on Hcy-induced apoptosis of human umbilical vein endothelial cells (HUVECs) was examined. The expression of ERα and DNA methyltransferases 1 (DNMT1) were detected by Western blot and real-time polymerase chain reaction (RT-PCR). The methylation rate of the ERα gene was assayed by the bisulfite sequencing PCR (BSP). High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) was applied to determine the level of S-Adenosyl methionine (SAM) and S-Adenosyl homocysteine (SAH). In vivo, the ApoE-/- mice were ovariectomized to establish postmenopausal atherosclerosis (AS) model. RESULTS: In vitro study showed that LWDH protects HUVECs from Hcy-induced apoptosis. Treatment with LWDH significantly increased the ERα expression and reduced the methylation rate of the ERα gene by inhibiting the DNMT1 expression. The level of main methyl donor SAM and the ration of SAM/SAH were reduced by LWDH. In vivo, LWDH prevented the formation of plaque and reduced the concentration of Hcy. In addition, LWDH upregulated the ERα expression, as well as inhibiting the expression of DNMT1 in atherosclerotic mice. CONCLUSIONS: LWDH exerted protective effects on postmenopausal AS mice, and HUVECs treated with Hcy. LWDH increased of ERα expression via inhibiting DNMT1-dependent ERα methylation.

Liuwei Dihuang soft capsules inhibits the phenotypic conversion of VSMC to prevent the menopausal atherosclerosis by up-regulating the expression of myocardin.

ETHNOPHARMACOLOGICAL RELEVANCE: Liuwei Dihuang (LWDH) is a classic prescription that has been used as a traditional medicinal formula for more than 1000 years in China. In clinical, LWDF is used for treating functional decline associated with senile disease and menopausal syndrome. Studies have demonstrated that LWDH could significantly improve estrogen level and ER expression, and suspend the process of atherosclerosis. However, the under mechanism of how LWDH suppressing VSMCs phenotypic conversion and proliferation through ER is still unknown. AIM OF THE STUDY: This study was to reveal the under mechanism of how LWDH inhibits the phenotypic conversion of VSMCs. MATERIALS AND METHODS: 24 ApoE-/- mice were divided into 4 groups: sham group, model group, E2 group, and LWDH group, and 6 C57BN/L6 mice were used as control group. The primary VSMCs were divided into control group, model group, E2 group, LWDH group, LWDH + MPP group, and LWDH + PHTPP group with or without control siRNA, ERα siRNA, ERß siRNA, and myocardin siRNA. Oil red staining was used to evaluate the lipid deposition in the cardiac aorta. Serum chemistry analysis to test serum TG, TC, LDL, and HDL. Immunofluorescence staining was used to test α-SMA, osteopontin and F-actin. Immunohistochemical staining was performed to check out the myocardin in the cardiac aorta. The mRNA levels of α-SMA, osteopontin, ERα, ERß, SRC3 and myocardin were detected by Real Time-PCR, and the protein expression levels of them were detected by Western blotting. Co-immunoprecipitation was proceed to test the interaction between ERα and SRC3 and SRC3 and myocardin. Flow cytometry was used to check out the cell cycle. Wound healing assay and Transwell were managed to evaluate the migration capacity of VSMCs. RESULTS: In vivo administration of LWDH suppressed AS symptoms, decreases phenotypic marker of vascular endothelial cell, and increases phenotypic marker of VSMC in ovariectomized ApoE-/- female mice. Moreover, LWDH significantly increased the mRNA and protein expression levels of ERα, ERß, SRC3 and myocardin in the cardiac aorta of ovariectomized ApoE-/- female mice. In vitro, LWDH altered cell cycle and reduced the elevated cyclinD protein expression migration capacity and in the model VSMCs. In addition, LWDH inhibited phenotypic conversion and promoted the expression of ER, SRC3, and myocardin of the primary VSMC phenotypic conversion model. Inhibition of ERα almost completely eliminated the impacts of LWDH on α- SMA and osteopontin. Furthermore, LWDH promoted the interaction between ERα and SRC3 and up-regulated the co-activation of SRC3 and myocardin. CONCLUSIONS: LWDH could inhibit the phenotypic conversion of VSMCs in vitro and in vivo by increasing the activity of myocardin through up-regulating the expression of ERα and promoting the interaction between ERα and SRC3. Our research reveals the under mechanism of how LWDH inhibits the phenotypic conversion of VSMCs.

Tongsaimai reverses the hypertension and left ventricular remolding caused by abdominal aortic constriction in rats.

Treating ventricular remodeling continues to be a clinical challenge. Studies have shown that hypertension is one of the most common causes of ventricular remodeling, and is a major cause of cardiovascular risk in adults. Here, we report that Tongsaimai (TSM), a Chinese traditional medicine, could inhibit arterial pressure and left ventricular pressure to improve hemodynamic abnormalities in rats impaired by abdominal aortic constriction (AAC). Administration of TSM significantly reduced the heart mass index and the left ventricular mass index significantly in AAC rats. TSM could also markedly ameliorate cardiac collagen deposition and reduce the concentration of hydroxyproline in the heart of AAC rats. Moreover, TSM alleviated cardiac histomorphology injury resulting from AAC, including reducing cardiomyocyte hypertrophy, fibrous connective tissue hyperplasia, cardiomyocyte apoptosis, replacement fibrosis and the disorders of myocardial myofibrils, intercalated discs, mitochondria and mitochondrial crista. In addition, the levels of transforming growth factor (TGF) - ß and inflammation-related molecules including tumor necrosis factor-α (TNF-α), which were over-expressed with AAC, were decreased by STM. In conclusion, STM could reverse the hypertension and left ventricular remolding caused by abdominal aortic constriction in rats.

Flavonoids extracted from mulberry (Morus alba L.) leaf improve skeletal muscle mitochondrial function by activating AMPK in type 2 diabetes.

ETHNOPHARMACOLOGICAL RELEVANCE: Mulberry (Morus alba L.) leaves have been widely applied to controlling blood glucose as a efficacious traditional Chinese medicine or salutary medical supplement. The extracts of mulberry leaf suppress inflammatory mediators and oxidative stress, protect the pancreatic ß-cells and modulate glucose metabolism in diabetic rats. Our previous studies and others have shown that mulberry leaf extract has excellent therapeutic effects on type 2 diabetes mellitus (T2DM), however, the underlying mechanism remains to be studied. AIM OF THE STUDY: Skeletal muscle insulin resistance (IR) plays an important role in the pathogenesis of T2DM. The aim of this study was to investigate the effects and mechanisms of Mulberry leaf flavonoids (MLF) in L6 skeletal muscle cells and db/db mice. MATERIALS AND METHODS: L6 skeletal muscle cells were cultured and treated with/without MLF for in vitro studies. For in vivo studies, the db/db mice with/without MLF therapy were used. Coomassie brilliant blue staining and α-SMA immunofluorescence staining were used to identify the differentiated L6 cells. Glucose level and ATP level of L6 myotubes were performed by optical density detection and cell viability was performed by MTT method. Mitochondrial membrane potential of L6 myotubes was detected by JC-1 fluorescent staining. ROS level of L6 myotubes was detected by DCFH-DA fluorescent staining. The body weight, food intake, and blood glucose of the mice were measured in different treatment days. Oral glucose tolerance test (OGTT), starch glucose tolerance test (STT) and insulin tolerance test (ITT) were performed in mice. Glycated hemoglobin, glycated serum protein, insulin, liver and muscle glycogen, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) of the mice were detected by corresponding kit. The pathologic change of pancreas and skeletal muscle of mice were performed by H & E staining. Immunohistochemistry staining was used to detect the GLUT4 and p-AMPK expressions in skeletal muscle in mice. GLUT4, CPT-1, NRF1, COXIV, PGC-1α, and p-AMPK expression levels in L6 cells and mice were detected by western bolt assay. RESULTS: MLF and metformin significantly ameliorated muscle glucose uptake and mitochondrial function in L6 muscle cells. MLF also increased the phosphorylation of AMPK and the expression of PGC-1α, and up-regulated the protein levels of m-GLUT4 and T-GLUT4. These effects were reversed by the AMPK inhibitor compound C. In db/db mice, MLF improve diabetes symptoms and insulin resistance. Moreover, MLF elevated the levels of p-AMPK and PGC-1α, raised m-GLUT4 and T-GLUT4 protein expression, and ameliorated mitochondrial function in skeletal muscle of db/db mice. CONCLUSIONS: MLF significantly improved skeletal muscle insulin resistance and mitochondrial function in db/db mice and L6 myocytes through AMPK-PGC-1α signaling pathway, and our findings support the therapeutic effects of MLF on type 2 diabetes.

Ginsenoside Rb2 inhibits epithelial-mesenchymal transition of colorectal cancer cells by suppressing TGF-ß/Smad signaling.

BACKGROUND: Treating colorectal cancer (CRC) continues to be a clinical challenge. Studies have shown that epithelial-mesenchymal transition (EMT) is a critical step in tumor progression and transforming growth factor-ß1 (TGF-ß1) signaling has been shown to play a crucial role in EMT. Here, we investigate the inhibition effect of Ginsenoside Rb2, main bioactive component of ginseng, in human colorectal cancer cells via TGF-ß1. PURPOSE: The current study aims to study the inhibitory effect of Ginsenoside Rb2 on HCT116 and SW620 cells and its anti-tumor mechanism. METHODS: Histomorphological analysis and western blot analysis were performed to evaluate expression of TGF-ß1 in human cancerous colon samples and the adjacent normal samples. The docking simulation assay were performed to explore the potential mode of binding of Ginsenoside Rb2 to the TGF-ß1 protein. CCK8, adhesion and invasion assay were used to assess the effects of Ginsenoside Rb2 in HCT116 and SW620 cells. RT-PCR, Western blot and Immunohistochemical staining were employed to detect the TGF-ß1-related signaling pathways in the colon cancer cells and/or xenograft mice. RESULTS: The expression of TGF-ß1 in human cancerous colon samples was significantly increased compared with the adjacent normal samples. Ginsenoside Rb2 inhibit the growth, adhesion, EMT and metastasis of human colorectal cancer cells. The docking simulation assay confirmed that Ginsenoside Rb2 bound to the hydrophobic pocket of TGF-ß1, which partially overlaps with the binding sites on TGF-ß1, and thus disrupted TGF-ß1 dimerization. Western Blot analysis further confirmed that Ginsenoside Rb2 could inhibit the expression of TGF-ß1 in vitro and in vivo. Furthermore, Ginsenoside Rb2 could inhibit the expression of Smad4 and phosphorylated Smad2/3. CONCLUSION: Ginsenoside Rb2 could inhibit EMT of colorectal cancer cells through the TGF-ß1/Smad signaling, and might be a potential candidate for the treatment of colorectal cancer.

A novel formula from mulberry leaf ameliorates diabetic nephropathy in rats via inhibiting the TGF-ß1 pathway.

INTRODUCTION: Based on the hypoglycemia and hypolipidemia of mulberry leaf and its extracts, we investigated the effect of a novel formula, Sang Tong Jian (STJ), from mulberry leaf on rats with diabetic nephropathy (DN). METHODS: The DN rats were induced by a long-term high-fat diet and a single streptozotocin injection. STJ was introduced for 12 weeks from the presence of hyperglycemia. The fasting blood glucose of DN rats was determined at weeks 5, 7, 9, and 11 respectively. The serum GSP, GHb and lipid profiles were analyzed by using a colorimetric method and ELISA kits. The kidney function of DN rats was demonstrated through the analysis of urine creatinine, urine albumin, serum urea nitrogen, serum creatinine and the creatinine clearance rate. The H-E (haematoxylin and eosin) and PAS (Periodic Acid-Schiff) staining were adopted to exhibit the morphology of the kidney. The TGF-ß1 and p-smad2/3, smad2/3, collagen IV, connexin 43 and E-cadherin were assayed via immunohistochemistry and western blot. RESULTS: STJ significantly decreased the fasting blood glucose (p < 0.01) and the glycation end product (p < 0.05), and regulated dyslipidemia. Inhibition of the thickening of the glomerular basement membrane and amelioration of the kidney function were shown in STJ-treated DN rats. Moreover, STJ decreased the levels of TGF-ß1, collagen IV, connexin 43 and activation of smad2/3 (p < 0.01), and enhanced E-cadherin (p < 0.01) in the kidney of DN rats. CONCLUSION: 12 week administration of STJ improved the metabolic parameters associated with blood glucose and lipid and inhibited the TGF-ß1 signaling pathway, which positively contributed to the amelioration of chronic diabetic kidney disease.

[Study of effect of tongsaimai tablets on experimental diabetic foot model rats].

OBJECTIVE: To observe the effect of Tongsaimai (TSM) tablets in treating foot trauma of diabetic foot (DF) model rats, and discuss its potential mechanism. METHOD: Male SD rats were selected to duplicate the diabetic foot ulcer model and randomly divided into the blank control group, the model group, the metformin treatment group, and TSM 12.44, 6.22, 3.11 g x kg(-1) groups (n = 10). The healing of ulcer wounds were observed on day 1, 4, 8, 13 and 18. After 18 days, a histopathologic examination was conducted for ulcer tissues. The contents of superoxide dismutase (SOD) and malondialdehyde (MDA) were detected by hydroxylamine and TBA methods. The content of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were determined with the radioimmunoassay. The immunohistochemical method was used to observe the expression of vascular endothelial growth factor (VEGF) in ulcer tissues and the number of capillary vessels. RESULT: TSM could alleviate the pathological changes of diabetic foot rats, accelerate the ulcer healing on 4, 8, 13, 18 d, reduce MDA, IL-6, TNF-alpha, VEGF content in rat serum at 18 d (after the rehabilitation period), and enhance the SOD content. Specifically, the TSM 12.44 g x kg(-1) group showed significant differences compared with the model group (P < 0.05, P < 0.01). At 18 d after the treatment (the late rehabilitation period), the VEGF expression of TSM 12.44, 6.22 g x kg(-1) groups and the number of blood capillaries of the TSM 12.44 g x kg(-1) group were significantly lower than that of the model group (P < 0.05, P < 0.01). CONCLUSION: TSM could promote the foot wound healing of DF model rats, reduce MDA, IL-6 and TNF-alpha levels in serum, increase the SOD content and decrease the VEGF expression and the number of blood capillaries in the late rehabilitation period. Its action mechanism may be related to the inhibition of oxidative stress injury and the inflammatory cell infiltration.