Weirong Wang

Buyang Huanwu decoction ameliorates coronary heart disease with Qi deficiency and blood stasis syndrome by reducing CRP and CD40 in rats

ETHNOPHARMACOLOGICAL RELEVANCE Qi deficiency and blood stasis is traditional Chinese medicine (TCM) syndrome. It leads to many diseases including coronary heart diseases (CHD) and cerebrovascular diseases (CVD). Inflammatory biomarkers and many endothelium-derived vasoactive factors are considered to play pivotal roles in CHD. Buyang Huanwu decoction (BYHWD), a TCM formula, has been recognized as a treatment for CHD with Qi deficiency and blood stasis syndrome and CVD in clinic. The mechanisms of BYHWD effect on CHD with Qi deficiency and blood stasis syndrome are unclear. AIM OF THE STUDY The aim is to investigate whether the effects of BYHWD on CHD with Qi deficiency and blood stasis syndrome in rats are associated with the inhibition of CRP, CD40 and vascular endothelial regulators. MATERIALS AND METHODS The treated groups were lavaged with 25.68, 12.84 and 6.42 g/kg BYHWD respectively once a day for 21 days. The level of C-reactive protein (CRP) in serum and the expression of cluster of differentiation 40 (CD40) in the heart and aorta of rats were detected. Moreover, the levels of thromboxaneA(2) (TXA(2)) and prostacyclin (PGI(2)) in plasma were measured and the levels of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in serum were detected. RESULTS BYHWD (25.68 g/kg) significantly decreased the level of CRP in serum and BYHWD (25.68 and 12.84 g/kg) decreased the expression of CD40 in the heart and aorta (P<0.01). The results also revealed that BYHWD (25.68 g/kg) inhibited the levels of iNOS in serum and TXA(2) in plasma and increased the levels of eNOS in serum and PGI(2) in plasma (P<0.01). CONCLUSION The study shows that the ameliorative effects of BYHWD on CHD with Qi deficiency and blood stasis syndrome in rats are associated with the inhibition of CRP and CD40 and the regulation of endothelium-derived vasoactive factors.

SIRT1 inhibits TNF-α-induced apoptosis of vascular adventitial fibroblasts partly through the deacetylation of FoxO1.

Sirtuin 1 (SIRT1), a NAD+-dependent class III histone deacetylase, participates in regulating cellular apoptosis, senescence and metabolism by deacetylating histones and multiple transcription factors. In this study, we aimed to determine the effect of SIRT1 on the apoptosis of vascular adventitial fibroblasts (VAFs) and related signaling pathways. SIRT1 was found in the nucleus of VAFs and translocated into the cytoplasm in response to tumor necrosis factor-α (TNF-α). Moreover, SIRT1 protein expression was reduced in VAFs stimulated with TNF-α. In addition, TNF-α increased the apoptosis of VAFs. Activation of SIRT1 by resveratrol (RSV) or overexpression of SIRT1 attenuated TNF-α-induced VAF apoptosis by decreasing the percentage of apoptotic cells and cleaved caspase-3 protein expression and increasing the Bcl-2/Bax ratio. In contrast, inhibition of SIRT1 by sirtinol/nicotinamide or knockdown of SIRT1 enhanced apoptosis of VAFs. On the other hand, knockdown of FoxO1 reduced TNF-α-induced VAF apoptosis. SIRT1 interacted with FoxO1 in VAFs by the co-immunoprecipitation assay. Further study showed that RSV or SIRT1 overexpression decreased acetylated-FoxO1 (Ac-FoxO1) protein expression in VAFs stimulated with TNF-α. Knockdown of SIRT1 resulted in an increase in Ac-FoxO1 protein expression. Taken together, these findings indicate that SIRT1 inhibits the apoptosis of VAFs, whereas FoxO1 promotes VAF apoptosis. Furthermore, the inhibitory effect of SIRT1 on VAF apoptosis is partly mediated by the deacetylation of FoxO1.

SIRT1 regulates TNF-α-induced expression of CD40 in 3T3-L1 adipocytes via NF-κB pathway.

Sirtuin1 (SIRT1), a NAD(+)-dependent deacetylase, not only regulates lipid and glucose homeostasis, but also involves the regulation of proinflammatory cytokine involved in inflammation-associated diseases. The activation of CD40 triggers inflammation that plays a crucial role in the development of many chronic inflammatory diseases including obesity. Growing evidence indicated that SIRT1 exerts anti-inflammatory properties by suppressing proinflammatory cytokines production. However, the effect of SIRT1 on the expression of CD40 in adipocytes has not yet been fully elucidated. The present study showed that SIRT1 expressed both in the nucleus and cytoplasm of 3T3-L1 adipocytes. TNF-α significantly reduced the expression of SIRT1 mRNA and protein and increased the expression of CD40 mRNA and protein in time- and concentration-dependent manners. Overexpression of SIRT1 or SIRT1 activation by resveratrol obviously attenuated the expression of CD40 induced by TNF-α in 3T3-L1 adipocytes, whereas knockdown of SIRT1 or SIRT1 inhibition by nicotinamide and sirtinol significantly enhanced TNF-α-induced expression of CD40. Furthermore, overexpression of SIRT1 or SIRT1 activation by resveratrol diminished TNF-α-induced acetylation of NF-κBp65, while knockdown of SIRT1 or SIRT1 inhibition by nicotinamide and sirtinol augmented TNF-α-induced acetylation of NF-κBp65 in 3T3-L1 adipocytes. NF-κB inhibitor PDTC reduced TNF-α-induced mRNA and protein expression of CD40 in 3T3-L1 adipocytes. The combination treatment of resveratrol and PDTC significantly reduced TNF-α-induced expression of CD40, and the inhibitory effects were higher than that of the single treatment. Taken together, SIRT1 exerts anti-inflammatory property by regulating TNF-α-induced expression of CD40 partially through the NF-κB pathway in 3T3-L1 adipocytes. More importantly, the regulation of SIRT1 on the expression of CD40 provides new insight to understand the anti-inflammatory effects of SIRT1.

SIRT1 Regulates CD40 Expression Induced by TNF-α via NF-ĸB Pathway in Endothelial Cells

Background: Compelling evidence suggests that SIRT1, NAD+-dependent class III protein deacetylase, plays an important role in the prevention and treatment of atherosclerosis by counteracting inflammation. Cluster of differentiation 40 (CD40), as a pro-inflammatory cytokine, has been shown to participate in the pathophysiology of atherosclerosis. The relationship between SIRT1 and CD40, however, remained elusive. The present study was thus designed to explore the potential effect of SIRT1 on CD40 expression induced by tumor necrosis factor-α (TNF-α) and to disclose the underlying mechanism in CRL-1730 endothelial cells. Methods: mRNA and protein expressions were identified by quantitative real-time PCR and Western blot respectively. Subcellular localization of SIRT1 was detected by immunofluorescence analysis. SIRT1 small-interfering RNA (siRNA) was carried out for mechanism study. Results: TNF-α reduced SIRT1 expression and induced CD40 expression in CRL-1730 endothelial cells in a time- and concentration- dependent manner. Pretreatment with resveratrol (a potent SIRT1 activator) inhibited TNF-α-induced CD40 expression, while pretreatment with nicotinamide (class b HDACs inhibitor nicotinamide) or sirtinol (a known SIRT1 inhibitor), especially SIRT1 siRNA significantly augmented TNF-α-induced CD40 expression. The frther sudy idicated that PDTC (NF-ĸB inhibitor) pretreatment attenuated TNF-α-induced CD40 expression, and SIRT1 siRNA significantly augmented TNF-α-induced acetylated-NF-ĸB p65 (Lys310) expression. Conclusion: The present study provides the direct evidence that SIRT1 can inhibit TNF-α- induced CD40 expression in CRL-1730 endothelial cells by deacetylating the RelA/p65 subunit of NF-ĸB at lysine 310, which provides new insights into understanding of the anti-inflammatory and anti-athroscerotic actions of SIRT1.

Protective effects of paeoniflorin against cobalt chloride-induced apoptosis of endothelial cells via HIF-1α pathway.

Accumulating evidence has suggested the importance of hypoxia in the initiation and development of atherosclerotic lesion, and hypoxia has a profound impact on endothelial cell properties during cardiovascular disease processes. Paeoniflorin, isolated from the root of Paeonia lactiflora pall, can protect endothelial cells from hypoxic damage in a variety of ways, such as by enhancing the production of nitric oxide (NO) and decreasing the expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). This study evaluated the protective effects of paeoniflorin against cobalt chloride (CoCl2, a hypoxia-mimicking agent)-induced apoptosis of endothelial cells (CRL-1730) and the underlying mechanisms in vitro. Endothelial cells were exposed to CoCl2 with or without pre-treatment with different concentrations of paeoniflorin. After treated with 0.6mM CoCl2 for 24 h, endothelial cells showed significant decrease in cell viability and increased apoptosis rate, which could be reversed by pre-treatment with paeoniflorin. Similarly, pre-treatment with paeoniflorin could prevent CoCl2-induced hypoxia-induced factor-1α (HIF-1α) accumulation and down-regulate the expressions of p53 and Bcl-2/adenovirus E1B 19kDa interacting protein 3 (BNIP3). These findings indicate that paeoniflorin had effective protection against hypoxia-induced apoptosis of endothelial cells and that HIF-1α, p53 and BNIP3 might be involved in this process.

Down-regulation of CD40 gene expression and inhibition of apoptosis with Danshensu in endothelial cells.

Danshen is commonly used in China for the treatment of atherosclerosis-related disorders such as cardiovascular and cerebrovascular diseases. Research shows that it also has immunostimulation properties. The present study evaluates the protective effect of danshensu, an active water-extractable component isolated from danshen, on an endothelial cell line (CRL-1730) treated with hydrogen peroxide (H(2)O(2)). Danshensu significantly inhibited endothelial cell viability induced by H(2)O(2). The treatment of endothelial cells with danshensu resulted in most cells being arrested in the S and G(2)/M phases of the cell cycle. The fraction of cells in G(0)/G(1) phase was markedly decreased by danshensu treatment compared to the control groups. The apoptosis was also markedly decreased after danshensu treatment. Additionally, danshensu restrains decreased nitric oxide level, increased the release of lactate dehydrogenase and expression of cluster of differentiation 40 (CD40) significantly. These results suggest that danshensu protects endothelial cells from the damage induced by H(2)O(2) through its CD40 anti-inflammatory approach and cell apoptosis inhibition.

The effects of Buyang Huanwu Decoction on hemorheological disorders and energy metabolism in rats with coronary heart disease

ETHNOPHARMACOLOGICAL RELEVANCE Buyang Huanwu Decoction (BYHWD), a traditional Chinese medicine (TCM) formula, has been recognized as a clinical treatment for coronary heart disease (CHD) with qi deficiency and blood stasis syndrome. The effects of BYHWD on hemorheological disorders and energy metabolism in CHD with qi deficiency and blood stasis syndrome are still unclear. AIM OF THE STUDY To investigate whether the ameliorative effects of BYHWD on CHD rats with qi deficiency and blood stasis syndrome are associated with the regulation of hemorheological disorders and energy metabolism. MATERIALS AND METHODS The rats were lavaged with 25.68, 12.84 and 6.42 g/kg BYHWD (g weight of mixed crude drugs/kg body weight), respectively, once a day for 21 days. The body weight, exhaustive swimming time and tongue characters were observed and recorded. The whole blood viscosity and plasma viscosity were determined by hematology analyzer. The level of fibrinogen (Fbg) in plasma was determined by using Fbg assay kit. The platelet aggregation induced by adenosine diphosphatase was measured by semi-automatic whole blood platelet analyzer. The level of blood glucose (BG) was determined by LifeScan. The activity of Na(+)-K(+)-ATPase in heart tissues was detected by spectrophotometer. RESULTS BYHWD improved the exterior signs of qi deficiency and blood stasis syndrome in rats with CHD, including the body weight, exhaustive swimming time and tongue quality. The whole blood viscosity in rats treated with 25.68 g/kg BYHWD decreased at the shear rate of 10s(-1) (P<0.05) and the plasma viscosity decreased in rats treated with 25.68 and 12.84 g/kg BYHWD (P<0.05). The plasma Fbg level and the platelet aggregation decreased in rats treated with 25.68 g/kg BYHWD (P<0.01). The results also revealed that the BG level decreased and the Na(+)-K(+)-ATPase activity in heart tissues increased in rats treated with 25.68 and 12.84 g/kg BYHWD (P<0.01). CONCLUSION The results suggest that the ameliorative effects of BYHWD on CHD rats with qi deficiency and blood stasis syndrome are mediated by the improvement of hemorheological disorders and energy metabolism.

PPARα agonist fenofibrate attenuates TNF-α-induced CD40 expression in 3T3-L1 adipocytes via the SIRT1-dependent signaling pathway.

The ligand-activated transcription factor peroxisome proliferator-activated receptor-α (PPARα) participates in the regulation of cellular inflammation. More recent studies indicated that sirtuin1 (SIRT1), a NAD(+)-dependent deacetylase, regulates the inflammatory response in adipocytes. However, whether the role of PPARα in inflammation is mediated by SIRT1 remains unclear. In this study, we aimed to determine the effect of PPARα agonist fenofibrate on the expressions of SIRT1 and pro-inflammatory cytokine CD40 and underlying mechanisms in 3T3-L1 adipocytes. We found that fenofibrate inhibited CD40 expression and up-regulated SIRT1 expression in tumor necrosis factor-α (TNF-α)-stimulated adipocytes, and these effects of fenofibrate were reversed by PPARα antagonist GW6471. Moreover, SIRT1 inhibitors sirtinol/nicotinamide (NAM) or knockdown of SIRT1 could attenuate the effect of fenofibrate on TNF-α-induced CD40 expression in adipocytes. Importantly, NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) augmented the effect of fenofibrate on CD40 expression in adipocytes. Further study found that fenofibrate decreased the expression of acetylated-NF-κB p65 (Ac-NF-κB p65) in TNF-α-stimulated adipocytes, and the effect of fenofibrate was abolished by SIRT1 inhibition. In addition, fenofibrate up-regulated SIRT1 expression through AMPK in TNF-α-stimulated adipocytes. Taken together, these findings indicate that PPARα agonist fenofibrate inhibits TNF-α-induced CD40 expression in 3T3-L1 adipocytes via the SIRT1-dependent signaling pathway.

SIRT1 inhibits inflammatory response partly through regulation of NLRP3 inflammasome in vascular endothelial cells

Emerging evidence has indicated that vascular endothelial cells (ECs) not only form the barrier between blood and the vessel wall but also serve as conditional innate immune cells. Our previous study found that SIRT1, a class III histone deacetylase, inhibits the inflammatory response in ECs. Recent studies revealed that SIRT1 also participates in the modulation of immune responses. Although the NLRP3 inflammasome is known to be a crucial component of the innate immune system, there is no direct evidence demonstrating the anti-inflammatory effect of SIRT1 on ECs through the NLRP3 inflammasome. In this study, we observed that lipopolysaccharide (LPS) and adenosine triphosphate (ATP) triggered the activation of NLRP3 inflammasome in human umbilical vein ECs (HUVECs). Moreover, SIRT1 expression was reduced in HUVECs stimulated with LPS and ATP. SIRT1 activator inhibited the expression of monocyte chemotactic protein-1 (MCP-1) and C-reactive protein (CRP), whereas SIRT1 knockdown resulted in significant increases in MCP-1 and CRP levels in HUVECs stimulated with LPS and ATP. Importantly, the lack of SIRT1 enhanced NLRP3 inflammasome activation and subsequent caspase-1 cleavage. On the other hand, NLRP3 siRNA blocked the activation of the NLRP3 inflammasome in HUVECs stimulated with LPS plus ATP. Further study revealed that NLRP3 inflammasome blockade significantly reduced MCP-1 and CRP production in HUVECs. In vivo studies indicated that implantation of the periarterial carotid collar inhibited arterial SIRT1 expression in rabbits. Meanwhile, treatment with a SIRT1 activator decreased the expression levels of MCP-1 and CRP in collared arteries and the interleukin (IL)-1β level in serum. Taken together, these findings indicate that NLRP3 inflammasome activation promoted endothelial inflammation and that SIRT1 inhibits the inflammatory response partly through regulation of the NLRP3 inflammasome in ECs.

Activation of PPAR alpha by fenofibrate inhibits apoptosis in vascular adventitial fibroblasts partly through SIRT1-mediated deacetylation of FoxO1.

Recent studies demonstrated that the ligand-activated transcription factor peroxisome proliferator-activated receptorα (PPARα) acts in association with histone deacetylase sirtuin 1 (SIRT1) in the regulation of metabolism and inflammation involved in cardiovascular diseases. PPARα activation also participates in the modulation of cell apoptosis. Our previous study found that SIRT1 inhibits the apoptosis of vascular adventitial fibroblasts (VAFs). However, whether the role of PPARα in apoptosis of VAFs is mediated by SIRT1 remains unknown. In this study, we aimed to determine the effect of PPARα agonist fenofibrate on cell apoptosis and SIRT1 expression and related mechanisms in ApoE(-/-) mice and VAFs in vitro. We found that fenofibrate inhibited cell apoptosis in vascular adventitia and up-regulated SIRT1 expression in aorta of ApoE(-/-) mice. Moreover, SIRT1 activator resveratrol (RSV) further enhanced these effects of fenofibrate. In vitro study showed that activation of PPARα by fenofibrate inhibited TNF-α-induced cell apoptosis and cell cycle arrest in VAFs. Meanwhile, fenofibrate up-regulated SIRT1 expression and inhibited SIRT1 translocation from nucleus to cytoplasm in VAFs stimulated with TNF-α. Moreover, the effects of fenofibrate on cell apoptosis and SIRT1 expression in VAFs were reversed by PPARα antagonist GW6471. Importantly, treatment of VAFs with SIRT1 siRNA or pcDNA3.1(+)-SIRT1 showed that the inhibitory effect of fenofibrate on cell apoptosis in VAFs through SIRT1. On the other hand, knockdown of FoxO1 decreased cell apoptosis of VAFs compared with fenofibrate group. Overexpression of FoxO1 increased cell apoptosis of VAFs compared with fenofibrate group. Further study found that fenofibrate decreased the expression of acetylated-FoxO1 in TNF-α-stimulated VAFs, which was abolished by SIRT1 knockdown. Taken together, these findings indicate that activation of PPARα by fenofibrate inhibits cell apoptosis in VAFs partly through the SIRT1-mediated deacetylation of FoxO1.