Paeoniflorin Ameliorates Atherosclerosis by Suppressing TLR4-Mediated NF-κB Activation

Paeoniflorin Inhibits Mesangial Cell Proliferation and Inflammatory Response in Rats With Mesangial Proliferative Glomerulonephritis Through PI3K/AKT/GSK-3β Pathway

Mesangial proliferative glomerulonephritis (MPGN) is the most common type of chronic kidney disease in China, characterized by mesangial cell proliferation and inflammatory response. Paeoniflorin, an effective composition extracted from Radix Paeoniae Alba, has been used for various kinds of kidney diseases. However, there are no studies reporting the effects of paeoniflorin on MPGN. The present study aims to investigate whether paeoniflorin plays a role in MPGN and confirm the underlying molecular mechanisms. Our results manifested that paeoniflorin strongly restrained 24 h urinary protein and promoted renal function and dyslipidemia in a MPGN rat model. Moreover, paeoniflorin attenuated mesangial cell proliferation and inflammation both in MPGN rats and human mesangial cells (HMCs) treated with lipopolysaccharide (LPS). In detail, paeoniflorin decreased the number of mesangial cells and expressions of proliferation marker Ki67 in MPGN rats. Paeoniflorin also inhibited HMC proliferation and blocked cell cycle progression. In addition, the contents of inflammatory factors and the expressions of macrophage marker iNOS were decreased after paeoniflorin treatment. Furthermore, we found that the protective effect of paeoniflorin was accompanied by a strong inhibition of the phosphatidylinositol 3-kinase (PI3K)/AKT/glycogen synthase kinase (GSK)-3β pathway. Paeoniflorin enhanced the inhibitory effect of PI3K inhibitor LY294002 and suppressed the activated effect of PI3K agonist insulin-like growth factor 1 (IGF-1) on PI3K/AKT/GSK-3β pathway. In conclusion, these results demonstrated that paeoniflorin ameliorates MPGN by inhibiting mesangial cell proliferation and inflammatory response through the PI3K/AKT/GSK-3β pathway.

Exploration of the mechanisms of Ge Gen Decoction against influenza A virus infection

Ge Gen Decoction (GGD), a Traditional Chinese Medicine prescription, is mainly used to treat infectious respiratory diseases and can relieve the symptoms of influenza A virus (IAV) infection. However, the underlying mechanism of GGD against IAV infection remains unclear. In this study, we found that GGD had moderate anti-IAV activity in vitro. GGD was more effective when given before the viral infection and targeted the viral attachment and replication stages rather than the internalization stage. In vivo, GGD treatment reduced thevirus titers of lung tissue significantly and improved the survival rate, lung index, and pulmonary histopathological changes in H1N1-infected mice. We observed the changes in several key immuno-related indexes in GGD administrated H1N1-infected mice with anti-IAV drug oseltamivir phosphate as the control. GGD treatment decreased the expression of TNF-α and improved Th1/Th2 immune balance to reduce the excessive immune response in H1N1-infected mice. Besides, the expression of the toll-like receptor 7 signaling pathway in H1N1-infected mice decreased after GGD treatment. Our results showed that GGD has anti-IAV activity and can modulate the immune system to relieve lung inflammation.

Oscillatory Shear Stress Induces Oxidative Stress via TLR4 Activation in Endothelial Cells

Background

Oscillatory shear stress (OSS) disrupts endothelial homeostasis and promotes oxidative stress, which can lead to atherosclerosis. In atherosclerotic lesions, Toll-like receptor 4 (TLR4) is highly expressed. However, the molecular mechanism by which TLR4 modulates oxidative changes and the cell signaling transudation upon OSS is yet to be determined.

Methods and Results

Carotid artery constriction (CAC) surgery and a parallel-plate flow chamber were used to modulate shear stress. The results showed that OSS significantly increased the oxidative burden, and this was partly due to TLR4 activation. OSS activated NOX2 and had no significant influence to NOX1 or NOX4 in endothelial cells (ECs). OSS phosphorylated caveolin-1, promoted its binding with endothelial nitric oxide synthase (eNOS), and resulted in deactivation of eNOS. TLR4 inhibition restored levels of nitric oxide (NO) and superoxide dismutase (SOD) in OSS-exposed cells.

Conclusion

TLR4 modulates OSS-induced oxidative stress by activating NOX2 and suppressing eNOS.

Effect of paeoniflorin on cardiac remodeling in chronic heart failure rats through the transforming growth factor β1/Smad signaling pathway

Background

Cardiac remodeling is an important mechanism for the occurrence and development of chronic heart failure (CHF). Paeoniflorin (Pae) is the main active ingredient of Chinese herbaceous peony and has novel anti-inflammatory effect. This study was conducted to assess the effects and mechanisms of Pae on cardiac remodeling in CHF rats.

Methods

A cardiac remodeling rat model was induced by isoprenaline (Iso). Pae (20 µg/kg/d) was administrated to CHF rats for six weeks. Cardiac ultrasound was used to assess the structure and function of CHF rats. Collagen volume fraction (CVF) and perivascular collagen volume area of myocardial tissues were calculated. With real-time polymerase chain reaction and Western blot, the protein and mRNA levels of transforming growth factor β1 (TGF-β1) and Smad3 were detected.

Results

Compared to Iso group, Pae can alleviate cardiac remodeling and improve cardiac function in CHF rats. The levels of CVF and perivascular collagen volume area reduced in Pae group (P<0.05). The expression of TGF-β1 and Smad3 protein decreased in Pae and Cap group (P<0.05). Further, the expression of TGF-β1 and Smad3 mRNA also decreased markedly in the Pae group (P<0.05).

Conclusions

Pae could attenuate cardiac remodeling and improve cardiac function in CHF rats. The potential mechanism for the cardioprotective effect of Pae may be highly associated with the down-regulating of TGF-β1/Smad signaling pathway.

Paeoniflorin improves pressure overload-induced cardiac remodeling by modulating the MAPK signaling pathway in spontaneously hypertensive rats

Paeoniflorin (PF) is a main bioactive component of the root of Paeonia lactiflora Pal, and previous investigations suggest that it may impact cardiac remodeling in spontaneous hypertensive rats (SHR) via the MAPK signaling pathway. Thus, the purpose of this investigation was to examine the impacts of paeoniflorin cardiac function in SHR rats. Cardiac function and blood pressure were observed using echocardiography and non-invasive tail pressure gauge. Heart histopathology was assessed by histological staining and transmission electron microscopy. Genomic sequencing was performed and signaling pathway enrichment analyzed the function of differentially expressed genes(DEGs). Biochemical kits were used to analyze the serum level of proinflammatory cytokines including TNF-α, IL-6 and MCP-1. qRT-PCR proved the mRNA expression of Ngfr, Grin2b, and Ntf4. MAPK pathways were determined via western blot. Paeoniflorin decreased blood pressure and increased hemodynamic indexes. 131 DEGs were identified (SHR vs. PF), and mainly enriched on the MAPK signaling pathway. Paeoniflorin reduced IL-6, MCP-1, Ngfr, Grin2b, and Ntf4, and also decreased p-JNK, p-Erk1/2, and p-p38 proteins compared with the SHR group. Paeoniflorin attenuated cardiac hypertrophy, cardiac fibrosis, and inflammation, and subsequently improved LV function. In conclusion, the cardioprotective role of paeoniflorin was associated with the inhibition of MAPK signaling pathway.

Tetramethylpyrazine and Paeoniflorin Inhibit Oxidized LDL-Induced Angiogenesis in Human Umbilical Vein Endothelial Cells via VEGF and Notch Pathways

Atherosclerotic plaque angiogenesis is key factor in plaque instability and vulnerability, and low concentrations of oxidized low density lipoprotein (ox-LDL) promote the in vitro angiogenesis of endothelial cells and play an important role in plaque angiogenesis. Ligusticum chuanxiong Hort. and Radix Paeoniae Rubra herb pair in Chinese medicine obtains the optimum therapeutic efficacy in atherosclerosis, and their major active ingredients tetramethylpyrazine (TMP) and paeoniflorin (PF) are reported to alleviate atherosclerosis. The aim of this study was to investigate the effects of TMP and PF on ox-LDL-induced angiogenesis and the underlying mechanism. Human umbilical vein endothelial cells (HUVECs) were incubated with ox-LDL and were then treated with TMP, PF, or a combination of TMP and PF. Cell proliferation, migration, tube formation, and the expression of angiogenesis-related proteins were measured. Synergism was evaluated using the combination index in cell proliferation. We found that TMP and PF attenuated the in vitro angiogenesis in ox-LDL-induced HUVECs. In addition, the combination of TMP and PF not only inhibited the ox-LDL-induced expression of CD31, vascular endothelial growth factor (VEGF), and VEGF receptor 2 (VEGFR2) but also decreased the ox-LDL-induced expression of Notch1, Jagged1, and Hes1. In summary, the combination of TMP and PF suppresses ox-LDL-induced angiogenesis in HUVECs by inhibiting both the VEGF/VEGFR2 and the Jagged1/Notch1 signaling pathways, which might contribute to the stability of plaques in atherosclerosis.

Galgeun-tang Attenuates Cigarette Smoke and Lipopolysaccharide Induced Pulmonary Inflammation via IκBα/NF-κB Signaling

Galgeun-tang water extract (GGWE) is used to treat various diseases such as the common cold, eczema and asthma in China and Korea. In this study, we investigated the anti-inflammatory effect of GGWE using a cigarette smoke (CS)- and lipopolysaccharide (LPS)-induced induced pulmonary inflammation mouse model. The mice were exposed to CS for a total of seven days (eight cigarettes per day for 1 h) and LPS was administered intranasally to mice on day 4. GGWE was administered by oral gavage at doses of 50 mg/kg or 100 mg/kg 1 h before exposure to CS. GGWE decreased inflammatory cell counts, and expression of inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α) in bronchoalveolar lavage fluid (BALF) from mice exposed to CS and LPS. GGWE reduced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), as well as the phosphorylation of inhibitor of kappa-B subunit alpha (IκBα) and nuclear factor kappa-B (NF-κB) in CS- and LPS-exposed mice. Histological examinations revealed that GGWE suppressed inflammatory cell infiltration into lung tissue compared to untreated CS- and LPS-exposed mice. In conclusion, GGWE effectively suppressed CS- and LPS-induced pulmonary inflammation. Our results indicate that GGWE may be used as a protective drug to control pulmonary inflammation diseases such as chronic obstructive pulmonary disease.

Paeoniflorin inhibits mast cell-mediated allergic inflammation in allergic rhinitis

Paeoniflorin (PF), one of the main effective ingredients from the root of Paeonia lactiflora Pall., was reported to possess antitumor, anti-inflammatory, and antiallergic properties. However, the roles of PF in activated human mast cell line, HMC-1 cells, have not yet been elucidated. Thus, the aim of this study was to examine the antiallergic and anti-inflammatory effects of PF on phorbol-12-myristate 13-acetate plus calcium ionophore (PMACI)-induced human mast cells and to identify the mechanism responsible for these effects. Our results demonstrated that pretreatment with PF effectively attenuated PMACI-induced production of tumor necrosis factor-α and interleukin 1β in HMC-1 cells. In addition, PF significantly suppressed PMACI-induced histamine release and caspase-1 activation in HMC-1 cells. Furthermore, PF prevented the activation of nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in activated HMC-1 cells. In conclusion, we showed for the first time that PF attenuated the mast cell-mediated allergic inflammatory response through suppressing the NF-κB and MAPK signaling pathways.

The Use of Juçara (Euterpe edulis Mart.) Supplementation for Suppression of NF-κB Pathway in the Hypothalamus after High-Fat Diet in Wistar Rats

Obesity is associated with modern diets that are rich in saturated fatty acids. These dietary patterns are linked to low-grade proinflammatory mechanisms, such as the toll-like receptor 4/nuclear factor kappa-B (NF-κB) pathway rapidly activated through high-fat diets. Juçara is a berry rich in anthocyanins and unsaturated fatty acids, which prevents obesity and associated comorbidities. We evaluated the effect of different doses of freeze-dried juçara pulp on NF-κB pathway after the consumption of short-term high-fat diet. Male Wistar rats with ad libitum access to food and water were divided into four groups: Control diet (C), high-fat diet (HFC), high-fat diet with 0.25% juçara (HFJ 0.25%), and high-fat diet with 0.5% juçara (HFJ 0.5%). Energy intake and body weight gain were increased in HFC and HFJ 0.5% groups compared to C group. The hypothalamus weight reduced in the HFC group compared to C and HFJ 0.25% groups. Cytokines, MYD88, TRAF6, and pNF-κBp50 levels in the hypothalamus, serum triacylglycerol, LDL-cholesterol (LDL-C), and free fatty acid levels were improved in the HFJ 0.25% group. In summary, the HFJ 0.25% group had better protective effects than those in the HFJ 0.5%. Therefore, 0.25% juçara can be used to protect against central inflammation through the high-fat diet-induced NF-κB pathway.

The Signaling Pathways Involved in the Antiatherosclerotic Effects Produced by Chinese Herbal Medicines

Cardiovascular diseases (CVDs) are considered to be the predominant cause of death in the world. Chinese herb medicines (CHMs) have been widely used for the treatment of CVDs in Asian countries for thousands of years. One reason of high efficacy of CHMs in treating CVDs is attributed to their inhibition in atherosclerosis (AS) development, a critical contributor to CVDs occurrence. Cumulative studies have demonstrated that CHMs alleviate atherogenesis via mediating pathophysiologic events involved in AS. However, there is deficiency in the summaries regarding antiatherogenic signal pathways regulated by CHMs. In this review, we focus on the signal cascades by which herb medicines and relevant extractives, derivatives, and patents improve proatherogenic processes including endothelium dysfunction, lipid accumulation, and inflammation. We mainly elaborate the CHMs-mediated signaling pathways in endothelial cells, macrophages, and vascular smooth muscle cells of each pathogenic event. Moreover, we briefly describe the other AS-related factors such as thrombosis, autophagy, immune response, and noncoding RNAs and effects of CHMs on them in the way of cascade regulation, which is helpful to further illustrate the molecular mechanisms of AS initiation and progression and discover newly effective agents for AS management.

MiR-181a inhibits vascular inflammation induced by ox-LDL via targeting TLR4 in human macrophages

Atherosclerosis is a kind of chronic inflammation disease with lipid accumulation in in blood vessel linings. Increasing evidence has reported that microRNAs can exert crucial roles in atherosclerosis. In previous study, miR-181a has been implicated to be abnormally expressed in atherosclerosis mice, however its detailed function in atherosclerosis remains uninvestigated. Hence, in our current study, we focused on the biological role of miR-181a in atherosclerosis progression. Ox-LDL has been commonly identified as an important atherosclerosis regulator. We observed that ox-LDL induced THP-1 cell apoptosis dose-dependently and time- dependently. Meanwhile, 25 µg/ml ox-LDL can promote foam cell formation and increased miR-181a expression significantly. CD36 has been involved in atherosclerosis progression and it was found that overexpression of miR-181a inhibited its protein levels. Moreover, miR-181a mimics repressed foam cell formation, TC and TG levels induced by ox-LDL dramatically. In addition, miR-181a mimics were able to reverse THP-1 cell apoptosis, increased IL-6, IL-1β, and TNF-α protein expression triggered by 25 µg/ml ox-LDL. TLR4 has been linked to various inflammation-associated diseases. In our present study, TLR4 was indicated as miR-181a target and the binding correlation between them was validated by dual-luciferase reporter assay. In conclusion, these results improves the understanding of atherosclerosis modulated by miR-181a/TLR4 and can contribute to development of new approaches for atherosclerosis.

Paeoniflorin inhibits glioblastoma growth in vivo and in vitro: a role for the Triad3A-dependent ubiquitin proteasome pathway in TLR4 degradation

Background

Paeoniflorin, a polyphenolic compound derived from Radix Paeoniae Alba (Paeonia lactiflora), has exhibited anticancer activity in various human cancers, including glioblastoma. However, the mechanisms underlying the effects of this compound have not been fully elucidated. Toll-like receptor 4 (TLR4) plays an important role in the regulation of cancer cell proliferation and progression, and high TLR4 expression in glioblastoma specimens is associated with a poor prognosis. The present study aimed to investigate whether paeoniflorin suppresses glioblastoma via inhibition of TLR4 expression.

Methods

CCK-8 experiments and clone formation assay were performed to detect the cell proliferation. Western blotting was used to analyze protein expression levels. Detection of Triad3A binding with TLR4 was assessed by the immunoprecipitation. Orthotopic xenograft mouse model was used to evaluate the effect of paeoniflorin in vivo. MST was used to analyze the interaction between paeoniflorin and TLR4 protein.

Results

In our study, we found that paeoniflorin effectively inhibited glioblastoma growth and suppressed TLR4 protein levels, as well its downstream effectors both in vivo and in vitro. Moreover, when overexpressed TLR4 in glioblastoma abolished the effects of paeoniflorin on cell proliferation, migration, and invasion. Furthermore, we found that paeoniflorin decreased TLR4 protein through ubiquitination proteasome pathway (UPP)-mediated degradation in glioblastoma cells. Mechanistically, paeoniflorin promoted Triad3A to conjugate with TLR4, resulting in degradation. In addition, Triad3A-shRNA abolished paeoniflorin-enhanced UPP-mediated TLR4 degradation. Finally, we found that paeoniflorin could directly bind with TLR4 protein as assessed by MST assay.

Conclusion

Our study is the first to identify a novel mechanism for the antitumor activity of paeoniflorin, specifically: it decreases tumor growth by directly targeting TLR4 and modulating the TLR4/Triad3A-dependent axis, leading to TLR4 protein degradation and inhibition of glioblastoma cell progression in vitro and in vivo. Our current findings indicate that paeoniflorin is a potential glioblastoma therapeutic agent due to its Triad3A-dependent ubiquitin degradation of TLR4.

Paeoniflorin regulates osteoclastogenesis and osteoblastogenesis via manipulating NF-κB signaling pathway both in vitro and in vivo

The metabolic balance between synthesis and resorption of the bone is maintained by osteoblasts and osteoclasts, respectively. Identification of agents that stimulate bone formation and suppress excessive osteoclast formation, may aid in preventing and treating conditions like osteoporosis and periprosthetic loosening. Paeoniflorin is a natural product derived from Paeonia lactiflora Pall with anti-inflammatory, analgesic, and diuretic properties. However, the effect of paeoniflorin on osteoclastogenesis and osteoblastogenesis is unknown. Herein, we demonstrated that paeoniflorin has a dose-dependent suppressive action on RANKL-evoked osteoclast differentiation and bone resorption, achieved by inhibiting the NF-κB pathway and subunit p65 nuclear translocation. Simultaneously, paeoniflorin was also found to stimulate osteoblast differentiation and bone mineralization, in addition to rescuing TNFα-impaired osteoblastogenesis. At the molecular level, paeoniflorin was found to inhibit NF-κB transcriptional activity and stimulate osteoblastogenesis-related marker gene expression (ALP, osteocalcin, OPN and Runx2), a trend that was inhibited by p65 overexpression. In ovariectomized mice, paeoniflorin was found to improve osteoblast activity, inhibit osteoclast activity, and thus, reduce ovariectomy-induced osteoporosis. Our study demonstrated that paeoniflorin simultaneously suppressed osteoclastogenesis and facilitated osteoblastogenesis by manipulating the actions of NF-κB. Therefore, paeoniflorin may serve as an ideal therapeutic antidote for osteoporosis.