Anticancer Effects of Washed-Dehydrated Solar Salt Doenjang on Colon Cancer-Induced C57BL/6 Mice.

This study researched the mineral composition of Korean washed-dehydrated solar salt (WDS) without bittern. It also evaluated the anticancer effects of doenjang (WDSD) prepared using WDS on azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colon cancer in C57BL/6 mice. The mineral composition of WDS showed lower Mg (11.71 ± 1.89 g/kg) and S (9.77 ± 2.88 g/kg) contents, and it was confirmed that mice in the WDSD group (AOM/DSS+WDSD) displayed significantly lower weight loss, colon length reduction, and tumor formation compared with the control (Con) group. In addition, pathologically, it was confirmed that the extent of epithelial cell damage and inflammation in the colon tissue of the WDSD group was restored to a state similar to that of the Nor group. Besides, WDSD regulated the protein expression of apoptosis (Bcl-2-associated X protein [Bax], B cell lymphoma-2 [Bcl-2], B cell lymphoma-extra large [Bcl-xL], and caspase 9, caspase 3), and p53, p21, and proinflammatory cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α), thereby inducing the apoptosis and cell cycle arrest of cancer cells and suppressing inflammation. In addition, the intestinal microbiota of the mice treated with WDSD were more diverse, with an abundance of Bifidobacterium, a lactic acid bacterium beneficial to colon health, was also a greater presence of Faecalibaculum, which showed antitumor effects. These results indicate that solar salts and their different processing methods affect their functional health-promoting properties. In addition, the inhibitory effect on colon cancer was further enhanced when doenjang was prepared with WDS with low Mg and S content.

Neuroprotective effects of ATPase inhibitory factor 1 preventing mitochondrial dysfunction in Parkinson's disease.

Mitochondrial dysfunction is a key element in the progression of Parkinson's disease (PD). The inefficient operation of the electron transport chain (ETC) impairs energy production and enhances the generation of oxidative stress contributing to the loss of dopaminergic cells in the brain. ATPase inhibitory factor 1 (IF1) is a regulator of mitochondrial energy metabolism. IF1 binds directly to the F1Fo ATP synthase and prevents ATP wasting during compromised energy metabolism. In this study, we found treatment with IF1 protects mitochondria against PD-like insult in vitro. SH-SY5Y cells treated with IF1 were resistant to loss of ATP and mitochondrial inner membrane potential during challenge with rotenone, an inhibitor of complex I in the ETC. We further demonstrated that treatment with IF1 reversed rotenone-induced superoxide production in mitochondria and peroxide accumulation in whole cells. Ultimately, IF1 decreased protein levels of pro-apoptotic Bax, cleaved caspase-3, and cleaved PARP, rescuing SH-SY5Y cells from rotenone-mediated apoptotic death. Administration of IF1 significantly improved the results of pole and hanging tests performed by PD mice expressing human α-synuclein. This indicates that IF1 mitigates PD-associated motor deficit. Together, these findings suggest that IF1 exhibits a neuroprotective effect preventing mitochondrial dysfunction in PD pathology.

Biglycan reduces body weight by regulating food intake in mice and improves glucose metabolism through AMPK/AKT dual pathways in skeletal muscle.

While biglycan (BGN) is suggested to direct diverse signaling cascades, the effects of soluble BGN as a ligand on metabolic traits have not been studied. Herein, we tested the effects of BGN on obesity in high-fat diet (HFD)-induced obese animals and glucose metabolism, with the underlying mechanism responsible for observed effects in vitro. Our results showed that BGN administration (1 mg/kg body weight, intraperitoneally) significantly prevented HFD-induced obesity, and this was mainly attributed to reduced food intake. Also, intracerebroventricular injection of BGN reduced food intake and body weight. The underlying mechanism includes modulation of neuropeptides gene expression involved in appetite in the hypothalamus in vitro and in vivo. In addition, BGN regulates glucose metabolism as shown by improved glucose tolerance in mice as well as AMPK/AKT dual pathway-driven enhanced glucose uptake and GLUT4 translocation in L6 myoblast cells. In conclusion, our results suggest BGN as a potential therapeutic target to treat risk factors for metabolic diseases.

Effect of chitinase-3-like protein 1 on glucose metabolism: In vitro skeletal muscle and human genetic association study.

We investigated the effect of chitinase-3-like protein 1 (CHI3L1) on glucose metabolism and its underlying mechanisms in skeletal muscle cells, and evaluated whether the observed effects are relevant in humans. CHI3L1 was associated with increased glucose uptake in skeletal muscles in an AMP-activated protein kinase (AMPK)-dependent manner, and with increased intracellular calcium levels via PAR2. The improvement in glucose metabolism observed in an intraperitoneal glucose tolerance test on male C57BL/6J mice supported this association. Inhibition of the CaMKK was associated with suppression of CHI3L1-mediated glucose uptake. Additionally, CHI3L1 was found to influence glucose uptake through the PI3K/AKT pathway. Results suggested that CHI3L1 stimulated the phosphorylation of AS160 and p38 MAPK downstream of AMPK and AKT, and the resultant GLUT4 translocation. In primary myoblast cells, stimulation of AMPK and AKT was observed in response to CHI3L1, underscoring the biological relevance of CHI3L1. CHI3L1 levels were elevated in cells under conditions that mimic exercise in vitro and in exercised mice in vivo, indicating that CHI3L1 is secreted during muscle contraction. Finally, similar associations between CHI3L1 and metabolic parameters were observed in humans alongside genotype associations between CHI3L1 and diabetes at the population level. CHI3L1 may be a potential therapeutic target for the treatment of diabetes.

Atorvastatin protects cardiomyocyte from doxorubicin toxicity by modulating survivin expression through FOXO1 inhibition.

BACKGROUND: Survivin has an anti-apoptotic effect against anthracycline-induced cardiotoxicity. Clinically, statin use is associated with a lower risk for heart failure in breast cancer patients with anthracycline chemotherapy. So, the purpose of our study was to investigate whether survivin mediates the protective effect of statin against anthracycline-induced cardiotoxicity. METHODS: Mice were treated once a week with 5 mg/kg doxorubicin for 4 weeks with or without atorvastatin 20 mg/kg every day then heart tissues were analyzed. Molecular and cellular biology analyses were performed with H9c2 cell lysates. RESULTS: Doxorubicin suppressed survivin expression via activation of FOXO1 in H9c2 cardiomyocytes. Whereas, atorvastatin inhibited FOXO1 by increasing phosphorylation and inhibiting nuclear localization. Doxorubicin induced FOXO1 binding to STAT3 and prevented STAT3 from interacting with Sp1. However, atorvastatin inhibited these interactions and stabilized STAT3/Sp1 transcription complex. Chromatin immunoprecipitation analysis demonstrated that doxorubicin decreased STAT3/Sp1 complex binding to survivin promoter, whereas atorvastatin stabilized this binding. In mouse model, atorvastatin rescued doxorubicin-induced reduction of survivin expression and of heart function measured by cardiac magnetic resonance imaging. CONCLUSIONS: Our study suggested a new pathophysiologic mechanism that survivin mediated protective effect of atorvastatin against doxorubicin-induced cardiotoxicity via FOXO1/STAT3/Sp1 transcriptional network.

ATP synthase inhibitory factor 1 (IF1), a novel myokine, regulates glucose metabolism by AMPK and Akt dual pathways.

ATPase inhibitory factor 1 (IF1) is an ATP synthase-interacting protein that suppresses the hydrolysis activity of ATP synthase. In this study, we observed that the expression of IF1 was up-regulated in response to electrical pulse stimulation of skeletal muscle cells and in exercized mice and healthy men. IF1 stimulates glucose uptake via AMPK in skeletal muscle cells and primary cultured myoblasts. Reactive oxygen species and Rac family small GTPase 1 (Rac1) function in the upstream and downstream of AMPK, respectively, in IF1-mediated glucose uptake. In diabetic animal models, the administration of recombinant IF1 improved glucose tolerance and down-regulated blood glucose level. In addition, IF1 inhibits ATP hydrolysis by ß-F1-ATPase in plasma membrane, thereby increasing extracellular ATP and activating the protein kinase B (Akt) pathway, ultimately leading to glucose uptake. Thus, we suggest that IF1 is a novel myokine and propose a mechanism by which AMPK and Akt contribute independently to IF1-mediated improvement of glucose tolerance impairment. These results demonstrate the importance of IF1 as a potential antidiabetic agent.-Lee, H. J., Moon, J., Chung, I., Chung, J. H., Park, C., Lee, J. O., Han, J. A., Kang, M. J., Yoo, E. H., Kwak, S.-Y., Jo, G., Park, W., Park, J., Kim, K. M., Lim, S., Ngoei, K. R. W., Ling, N. X. Y., Oakhill, J. S., Galic, S., Murray-Segal, L., Kemp, B. E., Mantzoros, C. S., Krauss, R. M., Shin, M.-J., Kim, H. S. ATP synthase inhibitory factor 1 (IF1), a novel myokine, regulates glucose metabolism by AMPK and Akt dual pathways.

New role of human ribosomal protein S3: Regulation of cell cycle via phosphorylation by cyclin-dependent kinase 2.

Human ribosomal protein S3 (hRpS3) is a component of the 40S ribosomal subunit that associated in protein synthesis. hRpS3 has additional ribosomal functions such as DNA repair, transcription, metastasis, and apoptosis via interaction with numerous signaling molecules and has different modifications. Cyclin-dependent kinases (CDKs) are heterodimeric serine/threonine protein kinases that regulate cell cycle progression. Among its members, the Cdk1-cyclin B complex is known to control cell progression in the G2/M phase, while Cdk2-cyclin E/A complexes function in G1/S and S/G2 transition. In our previous study, we observed interaction between hRpS3 and Cdk1. The present study investigated the interaction between hRpS3 and Cdk2. Cdk2 phosphorylated hRps3 at amino acid residues S6 and T221 during the S-phase. Furthermore, hRpS3 knockdown delayed cell cycle progression by modulating the expression of cell cycle-related proteins, including cyclin B1 and cyclin E1. These findings suggest that hRpS3 is involved in Cdk2-mediated cell cycle regulation.

Resveratrol Inhibits Hypoxia-Induced Vascular Endothelial Growth Factor Expression and Pathological Neovascularization.

PURPOSE: To investigate the effects of resveratrol on the expression of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) in human adult retinal pigment epithelial (ARPE-19) cells, and on experimental choroidal neovascularization (CNV) in mice. MATERIALS AND METHODS: ARPE-19 cells were treated with different concentrations of resveratrol and then incubated under hypoxic conditions with subsequent evaluation of cell viability, expression of HIF-1α, and expression of VEGF. The effects of resveratrol on the synthesis and degradation of hypoxia-induced HIF-1α were evaluated using inhibitors of the PI3K/Akt/mTOR and the ubiquitin proteasome pathways. In animal studies, CNV lesions were induced in C57BL/6 mice by laser photocoagulation. After 7 days of oral administration of resveratrol or vehicle, which began one day after CNV induction, image analysis was used to measure CNV areas on choroidal flat mounts stained with isolectin IB4. RESULTS: In ARPE-19 cells, resveratrol significantly inhibited HIF-1α and VEGF in a dose-dependent manner, by blocking the PI3K/Akt/mTOR signaling pathway and by promoting proteasomal HIF-1α degradation. In mice experiments, orally administered resveratrol significantly inhibited CNV growth in a dose-dependent manner. CONCLUSION: Resveratrol may have therapeutic value in the management of diseases involving pathological neovascularization.

Insulin Protects Cardiac Myocytes from Doxorubicin Toxicity by Sp1-Mediated Transactivation of Survivin.

Insulin inhibits ischemia/reperfusion-induced myocardial apoptosis through the PI3K/Akt/mTOR pathway. Survivin is a key regulator of anti-apoptosis against doxorubicin-induced cardiotoxicity. Insulin increases survivin expression in cardiac myocytes to mediate cytoprotection. However, the mechanism by which survivin mediates the protective effect of insulin against doxorubicin-associated injury remains to be determined. In this study, we demonstrated that pretreatment of H9c2 cardiac myocytes with insulin resulted in a significant decrease in doxorubicin-induced apoptotic cell death by reducing cytochrome c release and caspase-3 activation. Doxorubicin-induced reduction of survivin mRNA and protein levels was also significantly perturbed by insulin pretreatment. Reducing survivin expression with survivin siRNA abrogated insulin-mediated inhibition of caspase-3 activation, suggesting that insulin signals to survivin inhibited caspase-3 activation. Interestingly, pretreatment of H9c2 cells with insulin or MG132, a proteasome inhibitor, inhibited doxorubicin-induced degradation of the transcription factor Sp1. ChIP assay showed that pretreatment with insulin inhibited doxorubicin-stimulated Sp1 dissociation from the survivin promoter. Finally using pharmacological inhibitors of the PI3K pathway, we showed that insulin-mediated activation of the PI3K/Akt/mTORC1 pathway prevented doxorubicin-induced proteasome-mediated degradation of Sp1. Taken together, insulin pretreatment confers a protective effect against doxorubicin-induced cardiotoxicity by promoting Sp1-mediated transactivation of survivin to inhibit apoptosis. Our study is the first to define a role for survivin in cellular protection by insulin against doxorubicin-associated injury and show that Sp1 is a critical factor in the transcriptional regulation of survivin.

Arginase inhibition ameliorates adipose tissue inflammation in mice with diet-induced obesity.

This study examined whether oral administration of an arginase inhibitor regulates adipose tissue macrophage infiltration and inflammation in mice with high fat diet (HFD)-induced obesity. Male C57BL/6 mice (n = 30) were randomly assigned to control (CTL, n = 10), HFD only (n = 10), and HFD with arginase inhibitor N(ω)-hydroxy-nor-l-arginine (HFD with nor-NOHA, n = 10) groups. Plasma and mRNA levels of cytokines in epididymal adipose tissues (EAT), macrophage infiltration into EAT, and macrophage phenotype polarization were measured in the animals after 12 weeks. Additionally, the effects of nor-NOHA on adipose tissue macrophage infiltration and mRNA expression of cytokines were measured in co-cultured 3T3-L1 adipocytes and RAW 264.7 macrophages. Macrophage infiltration into the adipocytes was significantly suppressed by nor-NOHA treatment in adipocyte/macrophage co-culture system and mice with HFD-induced obesity. Pro-inflammatory cytokines, including monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), were significantly downregulated, and the anti-inflammatory cytokine IL-10 was significantly upregulated in nor-NOHA-treated co-cultured cells. In the mice with HFD-induced obesity, plasma and mRNA levels of MCP-1 significantly reduced after supplementation with nor-NOHA. In addition, oral supplement of nor-NOHA modified M1/M2 phenotype ratio in the EAT. Oral supplementation of an arginase inhibitor, nor-NOHA, altered M1/M2 macrophage phenotype and macrophage infiltration into HFD-induced obese adipose tissue, thereby improved adipose tissue inflammatory response. These results may indicate that arginase inhibition ameliorates obesity-induced adipose tissue inflammation.

Functional interaction between hMYH and hTRADD in the TNF-α-mediated survival and death pathways of HeLa cells.

UNLABELLED: The tumor necrosis factor (TNF) signaling pathway is a classical immune system pathway that plays a key role in regulating cell survival and apoptosis. The TNF receptor-associated death domain (TRADD) protein is recruited to the death domain of TNF receptor 1 (TNFR1), where it interacts with TNF receptor-associated factor 2 (TRAF2) and receptor-interacting protein (RIP) for the induction of apoptosis, necrosis, nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), and mitogen-activated protein (MAP) kinase activation. In this study, we found that the human MutY homolog (hMYH) interacted with human TRADD (hTRADD) via the C-terminal domain of hMYH. Moreover, under conditions promoting TNF-α-induced cell death or survival in HeLa cells, this interaction was weakened or enhanced, respectively. The interaction between hMYH and hTRADD was important for signaling pathways mediated by TNF-α. Our results also suggested that the hTRADD-hMYH association was involved in the nuclear translocation of NFκB and formation of the TNFR1-TRADD complex. Thus, this study identified a novel mechanism through which the hMYH-hTRADD interaction may affect the TNF-α signaling pathway. IMPLICATIONS: In HeLa cells, the hTRADD-hMYH interaction functioned in both cell survival and apoptosis pathways following TNF-α stimulation.

PPARα agonists inhibit inflammatory activation of macrophages through upregulation of ß-defensin 1.

BACKGROUND: Effects of peroxisome proliferator-activated receptor alpha (PPARα) agonists on cardiovascular outcome have been controversial. Although these agents primarily affect lipoprotein metabolism, their pleiotropic anti-inflammatory effect is one of the potential anti-atherosclerotic mechanisms. This study aimed to evaluate the effect of fenofibrate and gemfibrozil on inflammation in macrophages and reveal pathways these agents may affect. METHODS AND RESULTS: The two PPARα agonists inhibited secretion of CXCL2, TNF-α, IL-6, activation of p65 of NF-κB, ERK, and TLR4 expression. These changes occurred simultaneously with upregulation and secretion of ß-defensin 1, an inflammation-modulating peptide. To demonstrate the role of ß-defensin 1, it was knocked-down by target-specific siRNA. The effects of PPARα agonists on TLR4 expression and chemokine secretion were obviously abrogated with this treatment. In experiments investigating whether ß-defensin 1 acts extracellularly, inflammatory chemokines decreased significantly after the addition of recombinant ß-defensin 1 or conditioned media to cells. In experiments designed to clarify if the effects of the two agents are PPARα-dependent, induction of mRNA and secretion ß-defensin 1 and inhibition of chemokine release were clearly reduced with GW6471, a PPARα blocker. CONCLUSIONS: Our results reveal the pathways by which fenofibrate and gemfibrozil inhibit LPS-induced inflammatory activation of macrophages. This study elucidated a novel anti-inflammatory mechanism that acts through PPARα, ß-defensin 1, and TLR4 pathways.

C-reactive protein inhibits survivin expression via Akt/mTOR pathway downregulation by PTEN expression in cardiac myocytes.

C-reactive protein (CRP) is one of the most important biomarkers for arteriosclerosis and cardiovascular disease. Recent studies have shown that CRP affects cell cycle and inflammatory process in cardiac myocytes. Survivin is also involved in cardiac myocytes replication and apoptosis. Reduction of survivin expression is associated with less favorable cardiac remodeling in animal models. However, the effect of CRP on survivin expression and its cellular mechanism has not yet been studied. We demonstrated that treatment of CRP resulted in a significant decrease of survivin protein expression in a concentration-dependent manner in cardiac myocytes. The upstream signaling proteins of survivin, such as Akt, mTOR and p70S6K, were also downregulated by CRP treatment. In addition, CRP increased the protein and mRNA levels of PTEN. The siRNA transfection or specific inhibitor treatment for PTEN restored the CRP-induced downregulation of Akt/mTOR/p70S6K pathway and survivin protein expression. Moreover, pretreatment with a specific p53 inhibitor decreased the CRP-induced PTEN expression. ERK-specific inhibitor also blocked the p53 phosphorylation and PTEN expression induced by CRP. Our study provides a novel insight into CRP-induced downregulation of survivin protein expression in cardiac myocytes through mechanisms that involved in downregulation of Akt/mTOR/p70S6K pathway by expression of PTEN.

1-Deoxynojirimycin isolated from a Bacillus subtilis stimulates adiponectin and GLUT4 expressions in 3T3-L1 adipocytes.

We have demonstrated that 1-deoxynojirimycin (DNJ) isolated from Bacillus subtilis MORI could enhance the levels of adiponectin and its receptors in differentiated 3T3-L1 adipocytes, which has been shown to be effective in lowering blood glucose levels and enhancing insulin sensitivity. DNJ was not toxic to differentiated 3T3-L1 adipocytes for up to a concentration of 5 microM. In terms of expression levels of adiponectin and its receptors (AdipoR1 and AdipoR2), DNJ in concentrations as low as 0.5 microM elevated both mRNA and protein levels of adiponectin and transcript levels of AdipoR1 and AdipoR2. In addition, DNJ increased phosphorylation of 5' adenosine monophosphateactivated protein kinase (AMPK) in a statistically significant manner. Finally, treatment with DNJ resulted in increased mRNA expression of glucose transporter 4 (GLUT4), which encodes for a glucose transporter, along with a significant increase in glucose uptake into the adipocytes based on results of a 2-deoxy-D-[3H] glucose uptake assay. Our findings indicate that DNJ may greatly facilitate glucose uptake into adipose tissues by increasing the action of adiponectin via its up-regulated expression as well as its receptor genes. In addition, the glucose-lowering effects of DNJ may be achieved by an increased abundance of GLUT4 protein in the plasma membrane, as a consequence of the increased transcript levels of the GLUT4 gene and the activation of AMPK.

Quantitative assessment of aortic elasticity with aging using velocity-vector imaging and its histologic correlation.

OBJECTIVE: Velocity-vector imaging (VVI) represents a valuable new method for noninvasive quantification of vascular properties associated with aging. The purpose of this study was to assess the correlations between VVI parameters and histological changes with aging. APPROACH AND RESULTS: Fourteen mongrel dogs were classified as either young (n=7; age, 1-2 years; female; weighing 22-29 kg) or senescent (n=7; age, 8-12 years; female; weighing 36-45 kg). The short-axis image of the descending thoracic aorta was obtained for VVI analysis with transesophageal echocardiography. The location of the image was identified using fluoroscopic guidance, and the aortic tissue was extracted. After dividing the aortic wall into 6 segments, both regional and segmental tissue collagen and elastin contents were quantified and correlated with the aortic elastic properties. In the regional analysis, the M-mode-derived aortic dimensions and elastic moduli except for intima-media thickness were not significantly different between the groups, whereas the VVI-derived aortic area and fractional area changes showed more dilated and stiffer aorta in senescent dogs. Also, fractional area change was significantly correlated with the tissue collagen content unlike the M-mode-derived elastic moduli. In the segmental analysis, the radial velocity, circumferential strain, and strain rates of VVI were more reduced in senescent dogs than young dogs, and the radial velocity and circumferential strain showed independent associations with the collagen content of the corresponding aortic wall. CONCLUSIONS: VVI was a feasible method for direct quantification of aortic elastic properties with a significant histological correlation.

Hypocholesterolemic effect of daily fisetin supplementation in high fat fed Sprague-Dawley rats.

We aimed to test whether fisetin could modulate cholesterol homeostasis in rats with diet-induced hypercholesterolemia, and further investigated the underlying mechanisms by which fisetin exerts its cholesterol lowering effect. Blood lipid profile, hepatic cholesterol content, as well as gene expressions in cholesterol metabolism were examined. Elevated levels of total cholesterol and LDL-cholesterol, along with hepatic cholesterol content in a high fat group were found to be significantly reduced by fisetin. The high fat diet significantly decreased hepatic mRNA levels of LDLR, SREBP2, HMGCR and PCSK9 in comparison to the control diet, however, fisetin did not further elicit any changes in mRNA levels of the same genes. The high fat diet dramatically increased the transcript levels of CYP7A1, which was subsequently reversed by the fisetin. In HepG2 cells, fisetin was found to increase the levels of a nuclear form of SREBP2 and LDLR. In conclusion, fisetin supplementation displayed hypocholesterolemic effects by modulating the expression of genes associated with cholesterol and bile acid metabolism.

Quercetin up-regulates expressions of peroxisome proliferator-activated receptor γ, liver X receptor α, and ATP binding cassette transporter A1 genes and increases cholesterol efflux in human macrophage cell line.

Cholesterol-laden macrophages trigger accumulation of foam cells and increase the risk of developing atherosclerosis. We hypothesized that quercetin could lower the content of cholesterol in macrophages by regulating the expression of the ATP binding cassette transporter A1 (ABCA1) gene in differentiated human acute monocyte leukemia cell line (THP-1) cells and thereby reducing the chance of forming foam cells. Quercetin, in concentrations up to 30 µM, was not cytotoxic to differentiated THP-1 cells. Quercetin up-regulated both ABCA1 messenger RNA and protein expression in differentiated THP-1 cells, and its maximum effects were demonstrated at 0.3 µM for 4 to 8 hours in incubation. In addition, quercetin increased protein levels of peroxisome proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) within 2 hours of treatment. Because PPARγ and LXRα are important transcriptional factors for ABCA1, quercetin-induced up-regulation of ABCA1 may be mediated by increased expression levels of the PPARγ and LXRα genes. Furthermore, quercetin-enhanced cholesterol efflux from differentiated THP-1 cells to both high-density lipoprotein (HDL) and apolipoprotein A1. Quercetin at the dose of 0.15 µM elevated the cholesterol efflux only for HDL. At the dose of 0.3 µM, quercetin demonstrated effects both on HDL and apolipoprotein A1. Our data demonstrated that quercetin increased the expressions of PPARγ, LXRα, and ABCA1 genes and cholesterol efflux from THP-1 macrophages. Quercetin-induced expression of PPARγ and LXRα might subsequently affect up-regulation of their target gene ABCA1. Taken together, ingestion of quercetin or quercetin-rich foods could be an effective way to improve cholesterol efflux from macrophages, which would contribute to lowering the risk of atherosclerosis.

Human MutY homolog induces apoptosis in etoposide-treated HEK293 cells.

Etoposide (ETP) treatment of ataxia telangiectasia mutated (ATM) and Rad3-related protein (ATR)-, topoisomerase-binding protein-1 (TopBP1) and human MutY homolog (hMYH)-depleted cells results in a significant reduction in apoptotic signaling. The association between ATR or TopBP1 and hMYH increased following ETP treatment. In hMYH knockdown cells, the interaction between ATR and TopBP1 decreased following ETP treatment. We suggest that hMYH functions as a sensor of ETP-induced apoptosis. The results suggest that in the absence of hMYH, cells are unable to recognize the damage signal and the ATR pathway is not activated.

Quercetin up-regulates LDL receptor expression in HepG2 cells.

Quercetin, an abundant flavonol found in fruits and vegetable, has been implicated in lowering the risk of cardiovascular disease that is often associated with high plasma levels of low density lipoprotein (LDL) cholesterol. Here we investigated whether quercetin could modulate the expression of LDL receptors (LDLR) in HepG2 cells and the possible underlying mechanisms to exert quercetin's effects. We found that quercetin was able to induce LDLR expression with at least a 75 µ m concentration, which was accompanied by an increase in nuclear sterol regulatory element binding protein 2 (SREBP2). This effect was mediated by activation of c-jun-N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) signalling pathways as implicated by experiments using chemical inhibitors of each pathway. When cells were challenged with protein synthesis inhibitors in quercetin-activated LDLR transcription, LDL mRNA levels were not significantly affected by cycloheximide but puromycin abolished quercetin-induced LDLR transcription. Taken together, we conclude that quercetin can initiate LDLR transcription by enhancing SREBP2 processing, but new protein synthesis might be necessary to exert a maximum effect of quercetin in the up-regulation of the LDLR gene. Our findings demonstrate that quercetin strongly up-regulated LDLR gene expression, which might elicit hypolipidemic effects by increasing the clearance of circulating LDL cholesterol levels from the blood.

Palmitate promotes the paracrine effects of macrophages on vascular smooth muscle cells: the role of bone morphogenetic proteins.

Saturated fatty acids are known to activate macrophages and induce vascular inflammation. Although cytokines from activated macrophage influence other vascular cells, the influence of saturated fatty acids on the paracrine effect of macrophages is not fully understood yet. Here we examined the impact of palmitate on the effect of macrophages on vascular smooth muscle cells (SMCs) and their mediators. SMCs proliferation increased significantly after treatment with conditioned media from palmitate-stimulated RAW264.7 cells. SMC migration was found to be greater after treatment with palmitate-conditioned media. SM α-actin and SM22α were decreased in SMCs treated with palmitate-conditioned media. When stimulated with palmitate, RAW264.7 cells secreted more bone morphogenetic protein (BMP)2 and BMP4 into the cell culture media. SMC proliferation, migration, and phenotypic changes were attenuated after treatment of neutralizing antibodies against BMPs or knockdown of BMPs with siRNA. The influences of these proteins were further confirmed by direct treatment of recombinant BMP2 and BMP4 on SMCs. Particularly, the effects of BMPs on SMC migration on phenotypic change were obvious, whereas their effect on SMC proliferation seemed not significant or modest. In conclusion, palmitate promoted macrophages' paracrine effects on SMC proliferation, migration, and phenotypic change. The effect of stimulated macrophages was mediated, at least in part, by BMP2 and BMP4. These results suggest a novel mechanism linking saturated fatty acids and the progression of vascular diseases that is possibly mediated by BMPs from macrophages.