Kaempferol attenuates hyperglycemia-induced cardiac injuries by inhibiting inflammatory responses and oxidative stress

Use of a Systematic Pharmacological Methodology to Explore the Mechanism of Shengmai Powder in Treating Diabetic Cardiomyopathy

BACKGROUND Cardiovascular complications, such as diabetic cardiomyopathy (DCM), are the leading cause of death in diabetic patients. Shengmai Powder (SMP) was found to have cardioprotective effects. MATERIAL AND METHODS Based on the systematic pharmacological methodology, this research determined the genes of DCM and the known targets of SMP, predicted potential compounds and targets of SMP, constructed networks for DCM and SMP, and performed network analysis. RESULTS Five network were constructed: (1) the DCM gene PPI network; (2) the Compound-compound target network of SMP; (3) the SMP-DCM PPI network; (4) the Compound-known target network of SMP; (5) and the SMP known target-DCM PPI network. Several DCM and treatment related targets, clusters, signaling pathways, and biological processes were found. CONCLUSIONS SMP is able to regulate glycometabolism-related, lipid metabolism-related, inflammatory response-related, oxidative stress-related signaling pathways, and biological processes and targets, which suggests that SMP may have a therapeutic effect on DCM.

Kaempferol Improves Lung Ischemia-Reperfusion Injury via Antiinflammation and Antioxidative Stress Regulated by SIRT1/HMGB1/NF-κB Axis

Trauma, organ transplantation, and thromboembolism are the main causes of lung ischemia-reperfusion injury (LIRI), and new therapies and drugs are urgent to relieve LIRI. In preliminary experiment, authors found that kaempferol could improve LIRI in rats, and the current study further explored its possible mechanism. The model of rat LIRI was established and appropriate research methods were implemented. Results shown that kaempferol could significantly improve LIRI, inhibit release of inflammatory factors including interleukin (IL) 6 and tumor necrosis factor (TNF) α in bronchoalveolar lavage fluid, and reduce oxidative stress reaction. Western blotting was used to detect protein expression levels and found that kaempferol could up-regulate the protein expressions of phosphorylated (p-) p65 and p65, and down-regulate the protein expression of sirtuin (SIRT) 1. Immunofluorescence was used to localize the expression of high mobility group box (HMGB) 1 and found its higher expression in outside of nucleus. However, the above effects of kaempferol on LIRI markedly attenuated by EX 527, a selective inhibitor of SIRT 1. Taken together, we first reported the protective effect of kaempferol on rat LIRI and confirmed that kaempferol’s antiinflammation and antioxidative stress involving the SIRT1/HMGB1/NF-κB axis.

Therapeutic potential of IKK-β inhibitors from natural phenolics for inflammation in cardiovascular diseases

Cardiovascular disease (CVDs) is a chronic disease with the highest morbidity and mortality in the world. Previous studies have suggested that preventing inflammation serves an efficient role in protection against cardiovascular diseases. Modulation of IKK-β activity can be used to treat and control CVDs associated with chronic inflammation, which targets the phosphorylation of IκB following the release of the RelA complex, and then translocates to the nucleus, eventually triggering the transcription of several genes that induce chemokines, cytokines, and adhesion molecules. Most importantly, the IκB kinase (IKK) complex is involved in transcriptional activation by phosphorylating the inhibitory molecule IkBα, enabling activation of NF-κB. Phenolic compounds possess cardioprotective potential that may be related to modulating inflammatory responses involved in CVDs. The SystemsDock analysis was used to explore whether 38 active compounds inhibit IKK-β activity based on literature. Docking results showed that the top docking score of three chemical compounds were icariin, salvianolic acid B, and plantainoside D in all compounds. Icariin, salvianolic acid B, and plantainoside D are the most promising IKKβ inhibitors. These phytochemicals could be helpful to find the lead compounds on designing and developing novel cardioprotective agents.

Activation of TGR5 Partially Alleviates High Glucose-Induced Cardiomyocyte Injury by Inhibition of Inflammatory Responses and Oxidative Stress

High glucose- (HG-) induced cardiomyocyte injury is the leading cause of diabetic cardiomyopathy, which is associated with the induction of inflammatory responses and oxidative stress. TGR5 plays an important role in the regulation of glucose metabolism. However, whether TGR5 has cardioprotective effects against HG-induced cardiomyocyte injury is unknown. Neonatal mouse cardiomyocytes were isolated and incubated in a HG medium. Protein and mRNA expression was detected by western blotting and RT-PCR, respectively. Cell apoptosis was determined by Hoechst 33342 staining and flow cytometry. After treatment of cells with HG, TGR5-selective agonist INT-777 reduced the increase in expression of proinflammatory cytokines and NF-κB, whereas pretreatment of cells with TGR5 shRNA significantly reduced the inhibitory effects of INT-777. We also found that INT-777 increased the protein expression of Nrf2 and HO-1. In the presence of TGR5 shRNA, the expression of Nrf2 and HO-1 was reduced, indicating that TGR5 may exert an antioxidant effect partially through the Nrf2/HO-1 pathway. Furthermore, INT-777 treatment inhibited HG-induced ROS production and apoptosis that were attenuated in the presence of TGR5 shRNA or ZnPP (HO-1 inhibitor). Activation of TGR5 has cardioprotective effects against HG-induced cardiomyocyte injury and could be a pharmacological target for the treatment of diabetic cardiomyopathy.

Retinoic acid attenuates cardiac injury induced by hyperglycemia in pre- and post-delivery mice

The aim of the present study is to explore the effect of retinoic acid (RA) on cardiac injury induced by gestational diabetes mellitus (GDM). GDM mice were given 3 mg/kg RA once daily until the 19th day of pregnancy or the 7th day of post-partum. Compared to normal control and normal pregnant control mice, GDM mice before and after delivery showed significantly cardiac injury. RA treatment attenuated cardiac injury as evidenced by decreased heart mass and left ventricular mass, mRNA expressions of ANP and BNP, and cardiac fibrosis compared with that in GDM mice. The protective effect of RA on GDM cardiomyopathy was related to the decreased MDA content and ROS generation, the increased GSH-Px and SOD content as well as the reduced TNF-α and IL-1β content and inhibition of NF-κB signaling. In addition, RA treatment delayed the continuous rise of blood glucose before delivery and decreased the higher level of glucose after delivery. In conclusion, RA treatment could increase the activity of the antioxidant enzyme and suppress the oxidative stress, inflammation response, and activation of NF-κB signaling, thereby improving blood glucose level and cardiac injury of GDM mice before and after delivery.

Kaempferol alleviates the reduction of developmental competence during aging of porcine oocytes

Kaempferol (KAE) is a natural flavonoid present in different plant species and exhibits anti-inflammatory, antioxidant, and anticancer therapeutic properties. In the present study, we investigated the influence and underlying mechanisms of KAE supplementation on porcine oocytes during in vitro aging. The results show that KAE treatment can alleviate the aging-related reduction of developmental competence. We observed that the blastocyst production rate in aged oocytes treated with 0.1 μM KAE was significantly higher than in untreated aging oocytes (36.78 ± 0.86% vs. 27.55 ± 2.60%, respectively, p < .05). The KAE-treated aging oocytes had significantly reduced levels of reactive oxygen species (p < .05). Furthermore, the mRNA levels of the embryonic pluripotency-related genes Oct4, NANOG, and ITGA5 were significantly increased in blastocysts derived from KAE-treated oocytes (p < .05). During excessive oocyte culture, KAE treatment maintained the mitochondrial membrane potential and reduced apoptosis; however, this was not observed in untreated aging oocytes. In conclusion, our results suggest that KAE treatment can alleviate the aging of porcine oocytes by reducing oxidative stress and improving mitochondrial function.

Recent progress regarding kaempferol for the treatment of various diseases

Kaempferol, also known as kaempferol-3 or kaempferide, is a flavonoid compound that naturally occurs in tea, as well as numerous common vegetables and fruits, including beans, broccoli, cabbage, gooseberries, grapes, kale, strawberries, tomatoes, citrus fruits, brussel sprouts, apples and grapefruit. The present review mainly summarizes the application of kaempferol in treating diseases and the underlying mechanisms that are currently being studied. Due to its anti-inflammatory properties, it may be used to treat numerous acute and chronic inflammation-induced diseases, including intervertebral disc degeneration and colitis, as well as post-menopausal bone loss and acute lung injury. In addition, it has beneficial effects against cancer, liver injury, obesity and diabetes, inhibits vascular endothelial inflammation, protects the cranial nerve and heart function, and may be used for treating fibroproliferative disorders, including hypertrophic scar.

Amelioration effects of Kaempferol on immune response following chronic intermittent cold-stress

Cold-stress causes disturbance of the homeostatic regulation of animals, and gradually impairs the immune and antioxidant functions of animals. Therefore, increasing the effectiveness of the immune response and antioxidant function are the most attractive strategies against cold-stress. Kaempferol (KPF) exerts both an anti-inflammatory and antioxidant pharmacological effect. However, nor much is known of the effects of KPF on providing protection from cold-induced intestinal oxidative damage and improving immunity. This study investigated the effects of KPF on immune factors and intestinal antioxidation in the blood of cold-stressed mice. KPF was solubilized in diluted saline before administration. The mice were randomly divided into 4 groups: (1) control, (2) cold-stress, (3) KPF 25 mg/kg, and (4) cinnamon (CAM) 30 mg/kg groups. Groups (2)-(4) were exposed to cold stress once a day for 7 days. Cold-stress was achieved by exposing the mice to a temperature of -15 °C and 70 ± 10% humidity for 60 min, once a day. The histopathological changes in the small intestine of the mice were analyzed. The T lymphocyte populations in blood were measured using flow cytometry. The level of SLC6a4, 5-HT3 and 5-HTT in small intestine tissue was assessed using RT-PCR analysis. Cow blood samples were obtained for the hematological analysis. Kaempferol (KPF) (25 mg/kg) regularized the intestinal antioxidant activity in the cold stress animals. KPF was able to significantly (P < .05) return intestinal SLC6a4, 5-HT3 and 5-HTT levels to normal after it had increased due to cold-stress. KPF treatment prevented the cold stress-induced decrease in blood CD4⁺T cells and decrease CD8⁺T cells levels in mice. Improved hematological profiles were additionally observed on treatment cows with KPF. KPF compared favorably with cinnamon in cold stress management, suggesting cold stress disturbs the anti-inflammatory effect of KPF. Thus, KPF contributes to suppress the activated pro-inflammatory cytokines, IL-9, IL-13, CD8⁺T and neurochemicals, and to increase anti-inflammatory cytokines and CD4⁺T levels.

The protective effect of kaempferol on heart via the regulation of Nrf2, NF-κβ, and PI3K/Akt/GSK-3β signaling pathways in isoproterenol-induced heart failure in diabetic rats

This study was designed to delineate the effect of kaempferol (KF) on heart failure (HF) in diabetic rats. Streptozotocin-induced male diabetic rats received KF orally at 10 and 20 mg/kg for 42 consecutive days. In last 2 days of the experimental period, isoproterenol was subcutaneously injected at 85 mg/kg to induce HF. The hearts were processed for hemodynamic, biochemical, molecular, and histological investigations. Systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure were elevated in KF-treated HF-induced diabetic rats. Moreover, KF treatment resulted in decreased fasting blood glucose and glycosylated hemoglobin levels with increased serum insulin levels. Besides, serum cardiac injury markers like troponin-I, creatine kinase-muscle/brain, lactate dehydrogenase, and brain natriuretic peptide levels were significantly reduced in KF treatment. KF treatment has shown decrease in cardiac heme oxygenase-1, nuclear factor erythroid 2-related factor 2 (Nrf-2), and γ-glutamylcysteine synthetase with increased Keap1 mRNA levels. The cardioprotection of KF was improved by inhibition of apoptosis via blocking phosphorylation of Akt/glycogen synthase kinase (GSK)-3β and p38 mitogen-activated protein-kinase/extracellular signal-regulated kinases signaling pathways in HF-induced diabetic rats. Moreover, reduced cardiac apoptosis in KF treatment was confirmed by decreased terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) positive cells, histopathological changes in HF-induced diabetic rats. Therefore, the cardioprotective effect of KF is attributed to the regulation of Nrf2, nuclear factor kappa-light-chain-enhancer of activated B cells, and Akt/GSK-3β signaling pathways in HF-induced diabetic rats.

Kaempferol protects chondrogenic ATDC5 cells against inflammatory injury triggered by lipopolysaccharide through down-regulating miR-146a

Kaempferol is a kind of bioflavonoid exerts diverse pharmacological activities, including anti-apoptotic and anti-inflammatory activities. Kaempferol has been recognized as an effective agent for alleviating the clinical symptoms of osteoarthritis (OA). This study aimed to provide evidence that Kaempferol has potential in the management of OA. Lipopolysaccharide (LPS) stimulation induced a significant cell death and inflammatory injury in ATDC5 cells, as evidenced by the decreased cell viability, the induced apoptosis, the activated caspase-3, and the excessive production of IL-6, IL-8 and TNF-α. Precondition of cells with Kaempferol prevented apoptosis and the release of proinflammatory cytokines triggered by LPS. miR-146a was down-regulated by Kaempferol treatment, and Decorin was up-regulated by miR-146a overexpression. Consistently, both silence of miR-146a and Decorin exhibited Kaempferol-like effects towards ATDC5 cells stimulated by LPS. Moreover, Decorin silence activated PI3K/AKT/mTOR signaling pathway. In rat model of OA, the expression of miR-146a and Decorin in cartilage tissues was repressed by Kaempferol. Also, the activated PI3K/AKT/mTOR signaling pathway in OA animal model was enhanced by Kaempferol administration. These data suggested that Kaempferol exerted potential anti-OA effects through down-regulation of miR-146a, and thus repressing the expression of Decorin.

Kaempferol reduces K63-linked polyubiquitination to inhibit nuclear factor-κB and inflammatory responses in acute lung injury in mice

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), pose a major clinical challenge. The major driving force in this syndrome is pulmonary inflammation. Recent studies have shown that the naturally occurring flavonoid kaempferol (KPF) reduces endotoxin-induced inflammatory responses in mice. However, the mechanisms of these anti-inflammatory activities are not currently known. Here, we show that enhanced inflammatory cytokine production in response to lipopolysaccharide (LPS) is due to increased TGF-β-activated kinase-1 (TAK1) phosphorylation with subsequent activation of nuclear factor-κB (NF-κB). KPF attenuates LPS-mediated production of cytokines as well as activation of NF-κB. Furthermore, we identified that KPF prevents increased K63-linked polyubiquitination on TNF receptor associated factor-6 (TRAF6) and interleukin-1 receptor-associated kinase 1 (IRAK1). K63-linked polyubiquitination is a signal leading to enhanced activation of downstream pathways including TAK1. Our study shows that KPF is effective in reducing lung damage induced by LPS by modulating TRAF6 polyubiquitination. Furthermore, our findings may provide novel molecular targets to alleviate acute lung injury.

Mitochondrial Dysfunction-Associated Arrhythmogenic Substrates in Diabetes Mellitus

There is increasing evidence that diabetic cardiomyopathy increases the risk of cardiac arrhythmia and sudden cardiac death. While the detailed mechanisms remain incompletely understood, the loss of mitochondrial function, which is often observed in the heart of patients with diabetes, has emerged as a key contributor to the arrhythmogenic substrates. In this mini review, the pathophysiology of mitochondrial dysfunction in diabetes mellitus is explored in detail, followed by descriptions of several mechanisms potentially linking mitochondria to arrhythmogenesis in the context of diabetic cardiomyopathy.

Metformin alleviates hyperglycemia-induced apoptosis and differentiation suppression in osteoblasts through inhibiting the TLR4 signaling pathway

AIMS

Metformin was found to protect against hyperglycemia-induced injury in osteoblasts, but the cellular mechanisms involved remain unclear. Therefore, the aim of this study was to determine the effect of metformin on hyperglycemia-induced apoptosis and differentiation suppression in osteoblasts and to explore its relationships with the TLR4 signaling pathway.

MAIN METHODS

A mouse osteoblast cell line, MC3T3-E1, and a diabetic rat model were used to survey the protective effects of metformin on hyperglycemia-induced injury. TLR4 expression was altered using small interfering (si)RNA and lentivirus-mediated TLR4 overexpression. LPS was used as a specific TLR4 activator, and CLI-095 was used as a TLR4 inhibitor.

KEY FINDINGS

Metformin improved osteoblast differentiation, reduced apoptosis in hyperglycemic osteoblasts, and inhibited TLR4, MyD88 and NF-κB expression in a dose-dependent manner. Down-regulating the expression or inhibiting the activity of TLR4 enhanced these protective effects of metformin on osteoblast differentiation, cell viability and cell apoptosis in hyperglycemic conditions, whereas up-regulating the expression or activating the activity of TLR4 had the opposite effects. Activating NF-κB suppressed the protective effects of metformin, while inhibiting NF-κB activity had the opposite effects. Metformin increased ALP and OCN secretion, enhanced BMP-2 expression, improved bone mineral density (BMD), and decreased TLR4, MyD88 and NF-κB levels in the femur tissues of diabetic rats.

SIGNIFICANCE

Taken together our experimentation support the hypothesis that metformin may alleviate hyperglycemia-induced apoptosis and differentiation suppression in osteoblasts by inhibiting the TLR4/MyD88/NF-κB signaling pathway.

Apoptosis in angiotensin II-stimulated hypertrophic cardiac cells -modulation by phenolics rich extract of Boerhavia diffusa L

Herein, we investigated the effects of B. diffusa (BDE), a well-known cardiotonic edible medicinal plant against apoptosis in Angiotensin II (Ang II)-stimulated hypertrophic cardiac cells (H9c2). The cells were analyzed for viability, markers of hypertrophy, apoptosis, and the expression of various proteins related to apoptosis. Ang II (100 nM for 48 h)-exposed H9c2 cells treated with BDE (75 μg/ml) showed a significant reduction in apoptosis (58.60%↓) compared to Ang II-alone treated cells. BDE treatment significantly reduced the up-regulation of Bax and cytosolic cytochrome-C caused by Ang II as well as reduced the degree of Ang II- induced down-regulation of Bcl-2. A reduction in caspase-3 activity (33.77%↓) and down-regulation of TNF-α was also observed in BDE treated cells stimulated with Ang II. Furthermore, the up-regulation of phospho-p38 MAPK was attenuated by BDE treatment. Bioactive components in the extract were identified as boeravinone B, quercetin, kaempferol, and caffeic acid as evident from high-performance liquid chromatography (HPLC). Overall, our study shows that B. diffusa is effective in attenuating apoptosis in cardiac cells, which is a major contributor to sudden cardiac death in addition to its nutraceutical properties.

miRNA-29a inhibits colon cancer growth by regulation of the PTEN/Akt/GSK3β and Wnt/β-catenin signaling pathways

In the present study, the effects of microRNA-29a (miRNA-29a) on colon cancer cell viability and the molecular mechanisms underlying the effects were investigated. The expression of miRNA-29a in colon cancer serum samples was notably downregulated, compared with in the normal group. First, miRNA-29a mimic was used to increase the expression of miRNA-29a in HCT-116 cells. Furthermore, upregulation of miRNA-29a suppressed cell viability, increased lactate dehydrogenase levels and apoptosis, and promoted caspase-3/9 activities and B-cell lymphoma 2-associated X protein and phosphatase and tensin homolog (PTEN) protein expression in colon cancer cells. Furthermore, upregulation of miRNA-29a decreased phosphoinositide 3-kinase, phosphorylated (p)-protein kinase B (Akt) and p-glycogen synthase kinase 3β (GSK3β) protein expression and suppressed the Wnt/β-catenin signaling pathway in colon cancer cells. The results of the present study verified that the protective effects of miRNA-29a suppress the PTEN/Akt/GSK3β and Wnt/β-catenin signaling pathways in colon cancer.