Involvement of histamine in endothelium-dependent relaxation of mesenteric lymphatic vessels.

OBJECTIVES: The knowledge of the basic principles of lymphatic function, still remains, to a large degree, rudimentary and will require significant research efforts. Recent studies of the physiology of the MLVs suggested the presence of an EDRF other than NO. In this study, we tested the hypothesis that lymphatic endothelium-derived histamine relaxes MLVs. METHODS: We measured and analyzed parameters of lymphatic contractility in isolated and pressurized rat MLVs under control conditions and after pharmacological blockade of NO by L-NAME (100 µM) or/and histamine production by α-MHD (10 µM). Effectiveness of α-MHD was confirmed immunohistochemically. We also used immunohistochemical labeling and Western blot analysis of the histamine-producing enzyme, HDC. In addition, we blocked HDC protein expression in MLVs by transient transfection with vivo-morpholino oligos. RESULTS: We found that only combined pharmacological blockade of NO and histamine production completely eliminates flow-dependent relaxation of lymphatic vessels, thus confirming a role for histamine as an EDRF in MLVs. We also confirmed the presence of HDC and histamine inside lymphatic endothelial cells. CONCLUSIONS: This study supports a role for histamine as an EDRF in MLVs.

NS398 protects cells from sodium nitroprusside-mediated cytotoxicity through enhancing HO-1 induction independent of COX-2 inhibition.

Heme oxygenase-1 (HO-1) plays a preventive role in oxidative stress. In contrast, COX-2 is involved in the pathogenesis of many inflammatory diseases, thus COX-2 inhibitor is believed to exert anti-inflammatory properties by blocking COX-2. Recently, however, salicylate the active metabolite of aspirin showed COX-independent anti-inflammatory effects through induction of HO-1. Thus, we hypothesized that HO-1 are induced as an adaptive response to sodium nitroprusside (SNP) and play a protective role against cytotoxicity. Moreover, we investigated the protective effect of NS398 known as a selective COX-2 inhibitor on SNP-mediated cytotoxicity, and whether the protective effect of NS398 is due to COX-2 inhibition or not. SNP induced cytotoxicity in a dose-dependent manner, which was enhanced by inhibition of HO-1, suggesting that HO-1 acts in an adaptive response to SNP. Interestingly, NS398 decreased SNP-mediated cytotoxicity whereas COX-2 siRNA did not. Furthermore, NS398 enhanced SNP-induced HO-1 induction even though NS398 alone failed to induce HO-1 protein expression. In addition, NS398 enhanced SNP-induced COX-2, even though NS398 effectively inhibited SNP-mediated PGE(2) production. These results demonstrate that NS398 exerts cytoprotective effects by inducing HO-1 independent of COX-2 inhibition.

Tanshinone I suppresses growth and invasion of human breast cancer cells, MDA-MB-231, through regulation of adhesion molecules.

The role of cell adhesion molecules has been studied extensively in the process of inflammation, and these molecules are critical components of carcinogenesis and cancer metastasis. This study investigated the effect of tanshinone I derived from the traditional herbal medicine, Salvia miltiorrhiza Bunge, on the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in tumor necrosis factor-alpha (TNF-alpha)-stimulated endothelial cells. Furthermore, this study investigated the effect of tanshinone I on cancer growth, invasion and angiogenesis on human breast cancer cells MDA-MB-231, both in vitro and in vivo. Tanshinone I dose dependently inhibited ICAM-1 and VCAM-1 expressions in human umbilical vein endothelial cells (HUVECs) that were stimulated with TNF-alpha for 6 h. Pretreatment with tanshinone I significantly reduced adhesion of either monocyte U937 or MDA-MB-231 cells to HUVECs. Interestingly, the inhibitory effect of tanshinone I on monocyte and cancer cell adhesion to HUVECs was mimicked by transfection with ICAM-1 and VCAM-1 small interfering RNA. In addition, tanshinone I effectively inhibited TNF-alpha-induced production of vascular endothelial growth factor (VEGF) and VEGF-mediated tube formation in HUVECs. Tanshinone I also inhibited TNF-alpha-induced VEGF production in MDA-MB-231 cells and migration of MDA-MB-231 cells through extracellular matrix. Additionally, reduction of tumor mass volume and decrease of metastasis incidents by tanshinone I were observed in vivo. In conclusion, this study provides a potential mechanism for the anticancer effect of tanshinone I on breast cancer cells, suggesting that tanshinone I may serve as an effective drug for the treatment of breast cancer.

Tanshinone I effectively induces apoptosis in estrogen receptor-positive (MCF-7) and estrogen receptor-negative (MDA-MB-231) breast cancer cells.

Danshen (Salvia miltiorrhiza Bunge) is a herb that has been widely and successfully used for treating inflammatory diseases in clinics in Asia. The relatively abundant tanshinones, tanshinone I, tanshinone IIA, cryptotanshinone, and dihydrotanshinone, have been isolated from Danshen. These tanshinones are the major diterpenes isolated from Danshen, and show cytotoxic effects on cell lines derived from human carcinomas of the colon, ovary, lung, mouth, and breast. Recently, anti-cancer activities of tanshinone IIA have been reported, which suggest that the structurally similar tanshinone I may possess similar cytotoxic effects on tumor cells. We investigated the effect of tanshinone I on the induction of apoptosis in human breast cancer cells (MCF-7 and MDA-MB-231) in vitro. Tanshinone I inhibited cell proliferation of MCF-7 and MDA-MB-231 cells in a dose- and time-dependent manner, as assayed by MTT. In addition, TUNEL assay and flow cytometry showed that tanshinone I significantly induced apoptosis in MCF-7 and MDA-MB-231 cells. The induction of apoptotic cell death was mediated by the activation of caspase 3, the downregulation of the level of the anti-apoptotic protein, Bcl-2, and the upregulation of the level of the pro-apoptotic protein, Bax. Taken together, these results reveal a potential mechanism for the anti-cancer effect of tanshinone I on human breast cancer cells, and suggest that tanshinone I may serve as an effective adjunctive reagent in the treatment of human breast cancer.

Hesperidin, hesperidin methyl chalone and phellopterin from Poncirus trifoliata (Rutaceae) differentially regulate the expression of adhesion molecules in tumor necrosis factor-alpha-stimulated human umbilical vein endothelial cells.

The fruits of Poncirus trifoliata (L.) are widely used in Oriental medicine to treat allergic inflammation. Recently, several active compounds including hesperidin, hesperidin methyl chalone and phellopterin from P. trifoliata (Rutaceae) were isolated and characterized. The goal of this study was to investigate the differential effect of hesperidin, hesperidin methyl chalone and phellopterin derived from P. trifoliata (Rutaceae) on the induction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by TNF-alpha and the possible molecular mechanisms by which they differentially regulate ICAM-1 and VCAM-1 expressions. Stimulation of human umbilical vein endothelial cells (HUVECs) with TNF-alpha resulted in the increase of ICAM-1 and VCAM-1 expressions, while pretreatment with the three components completely inhibited VCAM-1 expression in a dose-dependent manner but had no effect on ICAM-1 expression. All three compounds failed to block TNF-alpha-induced phosphorylation of ERK1/2, which is involved in regulating ICAM-1 production by TNF-alpha. Furthermore, they efficiently inhibited the phosphorylation of Akt and PKC, suggesting that Akt or PKC pathways are an important target by which these compounds regulate TNF-alpha-induced VCAM-1 but not ICAM-1. Additionally, treatment with these chemicals also inhibited U937 monocyte adhesion to HUVECs stimulated with TNF-alpha. Interestingly, the inhibitory effect of hesperidin, hesperidin methyl chalone and phellopterin on monocyte adhesion to HUVECs was recapitulated by transfecting cells with VCAM-1 siRNA. Taken together, hesperidin, hesperidin methyl chalone and phellopterin reduce TNF-alpha-induced VCAM-1 expression through regulation of the Akt and PKC pathway, which contributes to inhibit the adhesion of monocytes to endothelium.

Bisacurone inhibits adhesion of inflammatory monocytes or cancer cells to endothelial cells through down-regulation of VCAM-1 expression.

Bisacurone, one of the active compounds of the traditionally used indigenous herb Curcuma longa Linne (Zingiberaceae), has anti-oxidant, anti-inflammatory, and anti-metastatic activities. We studied how the level of vascular cell adhesion molecule-1 (VCAM-1), one of the key molecules in the development of atherosclerosis as well as carcinogenesis and metastasis, might be affected by bisacurone in tumor necrosis factor-alpha (TNF-alpha)-activated human umbilical vein endothelial cells (HUVECs). Bisacurone dose-dependently inhibited TNF-alpha-mediated expression of VCAM-1. It showed significant suppressive effect on ROS generation in response to TNF-alpha stimulation and it blocked nuclear factor-kappa B (NF-kappaB) p65 translocation into the nucleus and phosphorylation of inhibitory factor kappaBalpha (IkappaBalpha). It also inhibited phosphorylation of Akt and PKC, which are upstream in the regulation of VCAM-1 by TNF-alpha. Furthermore, bisacurone decreased U937 monocyte and human oral cancer cell (Hep-2, QLL-I, SCC-15) adhesion to HUVECs stimulated by TNF-alpha, suggesting that it may inhibit the binding of these cells by regulating the expression of critical adhesion molecules by TNF-alpha. Thus, bisacurone may be beneficial in the treatment of inflammatory diseases, such as atherosclerosis, where inflammatory monocytes are involved in their pathology, and, moreover, in the development of tumors.

Paeonol suppresses intercellular adhesion molecule-1 expression in tumor necrosis factor-alpha-stimulated human umbilical vein endothelial cells by blocking p38, ERK and nuclear factor-kappaB signaling pathways.

Paeonol (2'-hydroxy-4'-methoxyacetophenone), the main active compound of the traditionally used Chinese herb Paeonia lactiflora Pallas, has anti-inflammatory, antioxidant and cardiovascular protective activities. We studied how the levels of intercellular adhesion molecule-1 (ICAM-1), one of the key molecules in the development of atherosclerosis, might be affected by paeonol in tumor necrosis factor-alpha (TNF-alpha)-activated human umbilical vein endothelial cells (HUVECs). Paeonol concentration-dependently inhibited the production of ICAM-1; it inhibited nuclear factor-kappaB (NF-kappaB) p65 translocation into the nucleus and the phosphorylation of inhibitory factor kappaBalpha (IkappaBalpha). It also blocked the TNF-alpha-induced phosphorylation of p38 and extracellular signal-regulated kinase (ERK), which are involved in regulating ICAM-1 production by TNF-alpha. Paeonol inhibited U937 monocyte adhesion to HUVECs stimulated by TNF-alpha, suggesting that it may inhibit the binding of monocytes to endothelium by regulating the production of critical adhesion molecules by TNF-alpha. The inhibitory effect of paeonol on ICAM-1 production might be mediated by inhibiting p38, ERK and NF-kappaB signaling pathways, which are involved in TNF-alpha-induced ICAM-1 production. Thus, paeonol may be beneficial in the treatment of cardiovascular disorders such as atherosclerosis.

Histamine as an Endothelium-Derived Relaxing Factor in Aged Mesenteric Lymphatic Vessels.

BACKGROUND: Knowledge of the mechanisms by which aging affects contracting lymphatic vessels remains incomplete; therefore, the functional role of histamine in the reaction of aged lymphatic vessels to increases in flow remains unknown. METHODS AND RESULTS: We measured and analyzed parameters of lymphatic contractility in isolated and pressurized rat mesenteric lymphatic vessels (MLVs) obtained from 9- and 24-month Fischer-344 rats under control conditions and after pharmacological blockade of nitric oxide (NO) by Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 100 µM) or/and blockade of histamine production by α-methyl-DL-histidine dihydrochloride (α-MHD, 10 µM). We also quantitatively compared results of immunohistochemical labeling of the histamine-producing enzyme, histidine decarboxylase (HDC) in adult and aged MLVs. Our data provide the first demonstration of an increased functional role of histamine as an endothelial-derived relaxing factor in aged MLVs, which appears in parallel with the abolished role of NO in the reactions of these lymph vessels to increases in flow. In addition, we found an increased expression of HDC in endothelium of aged MLVs. CONCLUSIONS: Our findings provide the basis for better understanding of the processes of aging in lymphatic vessels and for setting new important directions for investigations of the aging-associated disturbances in lymph flow and the immune response.

Mast cells and histamine are triggering the NF-κB-mediated reactions of adult and aged perilymphatic mesenteric tissues to acute inflammation.

This study aimed to establish mechanistic links between the aging-associated changes in the functional status of mast cells and the altered responses of mesenteric tissue and mesenteric lymphatic vessels (MLVs) to acute inflammation. We used an in vivo model of acute peritoneal inflammation induced by lipopolysaccharide treatment of adult (9-month) and aged (24-month) F-344 rats. We analyzed contractility of isolated MLVs, mast cell activation, activation of nuclear factor-κB (NF-κB) without and with stabilization of mast cells by cromolyn or blockade of all types of histamine receptors and production of 27 major pro-inflammatory cytokines in adult and aged perilymphatic mesenteric tissues and blood. We found that the reactivity of aged contracting lymphatic vessels to LPS-induced acute inflammation was abolished and that activated mast cells trigger NF-κB signaling in the mesentery through release of histamine. The aging-associated basal activation of mesenteric mast cells limits acute inflammatory NF-κB activation in aged mesentery. We conclude that proper functioning of the mast cell/histamine/NF-κB axis is necessary for reactions of the lymphatic vessels to acute inflammatory stimuli as well as for interaction and trafficking of immune cells near and within the collecting lymphatics.

Aging-related anatomical and biochemical changes in lymphatic collectors impair lymph transport, fluid homeostasis, and pathogen clearance.

The role of lymphatic vessels is to transport fluid, soluble molecules, and immune cells to the draining lymph nodes. Here, we analyze how the aging process affects the functionality of the lymphatic collectors and the dynamics of lymph flow. Ultrastructural, biochemical, and proteomic analysis indicates a loss of matrix proteins, and smooth muscle cells in aged collectors resulting in a decrease in contraction frequency, systolic lymph flow velocity, and pumping activity, as measured in vivo in lymphatic collectors. Functionally, this impairment also translated into a reduced ability for in vivo bacterial transport as determined by time-lapse microscopy. Ultrastructural and proteomic analysis also indicates a decrease in the thickness of the endothelial cell glycocalyx and loss of gap junction proteins in aged lymph collectors. Redox proteomic analysis mapped an aging-related increase in the glycation and carboxylation of lymphatic's endothelial cell and matrix proteins. Functionally, these modifications translate into apparent hyperpermeability of the lymphatics with pathogen escaping from the collectors into the surrounding tissue and a decreased ability to control tissue fluid homeostasis. Altogether, our data provide a mechanistic analysis of how the anatomical and biochemical changes, occurring in aged lymphatic vessels, compromise lymph flow, tissue fluid homeostasis, and pathogen transport.

Lymphatic muscle cells in rat mesenteric lymphatic vessels of various ages.

BACKGROUND: Recent studies on aging-associated changes in mesenteric lymph flow in situ demonstrated predominance of the severe negative chronotropic effect of aging on the contractility of aged mesenteric lymphatic vessels (MLV). At the same time, contraction amplitude of the aged vessels was only slightly diminished by aging and can be rapidly stimulated within 5-15 minutes. However, the detailed quantitative evaluation of potential aging-associated changes in muscle cells investiture in MLV has never been performed. METHODS AND RESULTS: In this study we, for the first time, performed detailed evaluation of muscle cells investiture in MLV in reference to the position of lymphatic valve in different zones of lymphangion within various age groups (3-mo, 9-mo and 24-mo Fischer-344 rats). Using visual and quantitative analyses of the images of MLV immunohistochemically labeled for actin, we confirmed that the zones located close upstream (pre-valve zones) and above lymphatic valves (valve zones) possess the lowest investiture of lymphatic muscle cells. Most of the high muscle cells investiture zones exist downstream to the lymphatic valve (post-valve zones). The muscle cells investiture of these zones is not affected by aging, while pre-valve and valve zones demonstrate significant aging-associated decrease in muscle cells investiture. CONCLUSIONS: The low muscle cells investiture zones in lymphatic vessels consist of predominantly longitudinally oriented muscle cells which are positioned in pre-valve and valve zones and connect adjacent lymphangions. These cells may provide important functional impact on the biomechanics of the lymphatic valve gating and electrical coupling between lymphangions, while their aging-associated changes may delimit adaptive reserves of aged lymphatic vessels.

Tanshinone IIA inhibits TNF-α-mediated induction of VCAM-1 but not ICAM-1 through the regulation of GATA-6 and IRF-1.

The goal of this study was to investigate the differential effect of tanshinone IIA on the induction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by TNF-α and the possible molecular mechanisms by which it regulates ICAM-1 and VCAM-1 expression differentially. Stimulation of human umbilical vein endothelial cells (HUVEC) with TNF-α increased ICAM-1 and VCAM-1 expressions, and the pretreatment with tanshinone IIA concentration dependently inhibited VCAM-1 expression but not ICAM-1 expression. In previous study, PI3K/Akt, PKC and Jak/STAT-3 pathways were involved in the TNF-α-mediated induction of VCAM-1 but not ICAM-1. Thus, we examined the effect of tanshinone IIA on TNF-α-mediated activations of PI3K/Akt, PKC and Jak/STAT-3 pathways. Tanshinone IIA efficiently inhibited the phosphorylations of Akt, PKC and STAT-3 by TNF-α. Moreover, we determined the effect of tanshinone IIA on IRF-1 or GATAs induction and binding activity to VCAM-1 promoter since the upstream promoter region of VCAM-1 but not ICAM-1 contains IRF-1 and GATA binding motifs. Western blot analysis and ChIP assay showed that tanshinone IIA efficiently inhibited TNF-α-increased nuclear level of IRF-1 and GATA-6 and their binding affinity to VCAM-1 promoter region. Taken together, tanshinone IIA selectively inhibits TNF-α-mediated expression of VCAM-1 but not ICAM-1 through modulation of PI3/Akt, PKC and Jak/STAT-3 pathway as well as IRF-1 and GATA-6 binding activity.

MKP-7, a negative regulator of JNK, regulates VCAM-1 expression through IRF-1.

Cell adhesion molecules (CAMs) are involved in a variety of pathologies including cancer, inflammation, pathogenic infections and autoimmune disease. In particular, VCAM-1, rather than ICAM-1, plays a major role in the initiation of atherosclerosis and tumor progression. Therefore, we attempted to elucidate differential mechanisms that regulate VCAM-1 and ICAM-1 expressions. Down-regulation of JNK by a specific inhibitor (SP600125) or dominant negative (DN) JNK1 plasmid enhanced TNF-α-induced VCAM-1 but not ICAM-1 expression. Moreover, transfection with a JNK1-overexpressing vector resulted in the inhibition of VCAM-1 expression stimulated by TNF-α in HUVECs, suggesting that JNK negatively regulates TNF-α-induced VCAM-1 expression in endothelial cells (ECs). Next, we investigated whether JNK signaling affects IRF-1 and/or GATA6, which are transcription factors that mediate TNF-α induction of VCAM-1 but not ICAM-1. The DN-JNK1 plasmid-transfected cells enhanced TNF-α up-regulation of IRF-1 whereas JNK1-overexpressing cells displayed down-regulation; however, neither DN-JNK1 transfection nor JNK1 overexpression affected GATA6 protein levels in the nuclear fraction. Chromatin immunoprecipitation (ChIP) assay confirmed that the inhibition of JNK by DN-JNK1 transfection increases the binding of IRF-1 to the VCAM-1 promoter whereas the overexpression of JNK1 inhibits IRF-1 binding to the VCAM-1 promoter. However, neither DN-JNK1 nor JNK1 overexpression altered GATA6 affinity for the VCAM-1 promoter region. We also examined whether MKP-7 affects ICAM-1 or VCAM-1 by regulating JNK. TNF-α-induced phosphor-JNK levels increased after 5min, peaked at 10 min, and decreased after 30 min. Interestingly, MKP-7 protein levels increased after 30 min, when phosphor-JNK induction by TNF-α was decreased. In addition, silencing MKP-7 with specific siRNA resulted in an increase in phosphor-JNK and inhibited the expression of VCAM-1 but not ICAM-1. Moreover, silencing MKP-7 caused the down-regulation of IRF-1 protein levels and binding to the VCAM-1 promoter. Thus, we suggest that MKP-7, a negative regulator of JNK, regulates VCAM-1 expression in activated endothelial cells through IRF-1 but not GATA6.

Metformin inhibits HMGB1 release in LPS-treated RAW 264.7 cells and increases survival rate of endotoxaemic mice.

BACKGROUND AND PURPOSE: Recently, metformin, a well-known anti-diabetic drug, has been shown to possess anti-inflammatory activities. This study investigated the effect of metformin on the expression of pro-inflammatory cytokines including high mobility group box 1 (HMGB1) in lipopolysaccharide (LPS)-treated animals and cells. EXPERIMENTAL APPROACH: We investigated whether metformin inhibits the release of HMGB1 in LPS-treated RAW 264.7 cells and increases survival rate in endotoxaemic mice (lethal endotoxaemia was induced by an i.p. injection of LPS). This was achieved by a range of techniques including Western blotting, enzyme-linked immunosorbent assay, specific pharmacological inhibitors, knock out of α(1) -subunit of AMP-activated protein kinase (AMPK) and recombinant HMGB1. KEY RESULTS: Both pre- and post-treatment with metformin significantly improved survival of animals during lethal endotoxaemia (survival rate was monitored up to 2 weeks), decreased serum levels of tumour necrosis factor-alpha (TNF-α), interleukin-1ß, HMGB1 expression and myeloperoxidase activity in lungs. However, metformin failed to improve survival in endotoxaemic animals that had additionally been treated with recombinant HMGB1. In an in vitro study, metformin dose-dependently inhibited production of pro-inflammatory cytokines and HMGB1 release. Metformin activated AMPK by its phosphorylation. Compound C (pharmacological inhibitor of AMPK) and siAMPKα1 reversed the anti-inflammatory effect of metformin in LPS-treated cells. CONCLUSIONS AND IMPLICATIONS: Our data indicate that metformin significantly attenuates the pro-inflammatory response induced by LPS both in vivo and in vitro. Metformin improved survival in a mouse model of lethal endotoxaemia by inhibiting HMGB1 release. AMPK activation was implicated as one of the mechanisms contributing to this inhibition of HMGB1 secretion.

Carbon monoxide from CORM-2 reduces HMGB1 release through regulation of IFN-ß/JAK2/STAT-1/INOS/NO signaling but not COX-2 in TLR-activated macrophages.

Reduction of high-mobility group box 1 (HMGB1) and NO levels may be important therapeutic strategy for treatment of sepsis. Recently, we found that carbon monoxide (CO) can reduce HMGB1 levels in septic animal models. Here, we tried to elucidate the molecular machinery of how CO inhibits HMGB1 release in toll-like receptor (TLR)-activated macrophages. Carbon monoxide-releasing molecule 2 (CORM-2) specifically inhibited the expression of iNOS (NO), but not of cyclooxygenase 2 (COX-2) (PGE2) in RAW 264.7 cells activated either by peptidoglycan (TLR-2 agonist), polyinosinic-polycytidylic acid (TLR-3 agonist), or LPS (TLR-4 agonist); this inhibition seemed to be mediated via the JAK2/STAT1 pathway. Treatment with neutralizing antibody to IFN-ß, a JAK2 inhibitor (AG490), or a STAT1 inhibitor (fludarabine) selectively inhibited iNOS, but not COX-2 in this system. Moreover, deletion of STAT1 by siRNA also showed preferential inhibition of iNOS but not COX-2 in LPS-treated cells. Carbon monoxide-releasing molecule 2 reduced IFN-ß production and phosphorylation of JAK2 and STAT1 in LPS-activated RAW264.7 cells. Carbon monoxide-releasing molecule 2 failed to inhibit iNOS and HMGB1 levels in the presence of recombinant IFN-ß and NO donor (NOC-18), respectively. Finally, plasma levels of HMGB1 and iNOS protein expression in lung tissues of cecal ligation and puncture-induced septic mice were decreased in the presence of CORM-2. Taken together, it is concluded that CO selectively inhibits iNOS over COX-2, at least through IFNß/JAK2/STAT1 signals, and this regulation plays an important role in the CORM-2-mediated inhibitory effect on HMGB1 release in macrophages.

PTEN differentially regulates expressions of ICAM-1 and VCAM-1 through PI3K/Akt/GSK-3ß/GATA-6 signaling pathways in TNF-α-activated human endothelial cells.

Phosphotase and tensin homolog deleted on chromosome 10 (PTEN) is a potent negative regulator of PI3K/Akt pathway. Here, we tried to elucidate the role of PTEN in the regulation of endothelial adhesion molecules, vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1, induced by TNF-α in human endothelial cells (ECs). Transfection with PTEN overexpressing vector resulted in the significant decrease in phosphorylation of Akt in TNF-α-treated ECs. PTEN strongly inhibited VCAM-1 but not ICAM-1, however this inhibitory effect was reversed by co-transfection with constitutively active-Akt (CA-Akt-HA) in TNF-α-stimulated ECs. Additionally, silencing of PTEN with specific siRNA showed significant increase of phosphor-Akt compared with TNF-α alone treated ECs. siPTEN significantly upregulated VCAM-1 but was indifferent to ICAM-1 in TNF-α-treated cells. Further, chromatin immunoprecipitation (ChIP) assay showed that PTEN targets GATA-6 but not IRF-1 binding to VCAM-1 promoter. In addition, GATA-6 is associated with glycogen synthesis kinase-3beta (GSK-3ß) which is in turn regulated by PTEN-dependent Akt activity. Finally, PTEN significantly prevented monocyte adhesion to TNF-α-induced ECs probably through VCAM-1 regulation. It is concluded that PTEN selectively inhibits expression of VCAM-1 but not ICAM-1 through modulation of PI3K/Akt/GSK-3ß/GATA-6 signaling cascade in TNF-α-treated ECs.

Carbon monoxide (from CORM-2) inhibits high glucose-induced ICAM-1 expression via AMP-activated protein kinase and PPAR-gamma activations in endothelial cells.

INTRODUCTION: Hyperglycemia is a risk factor for cardiovascular complications in diabetic state. Hyperglycemia-induced oxidative stress up-regulates intracellular adhesion molecule-1 (ICAM-1) which aggravates endothelial dysfunction, although the underlying mechanisms remain unclear. We hypothesized that carbon monoxide (CO) attenuates ICAM-1 expression induced by high glucose in endothelial cells through activation of AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor gamma (PPAR-gamma) pathway. METHODS: Human umbilical vein endothelial cells (HUVEC) were pre-treated with CO releasing molecule-2 (CORM-2) alone or in combination with troglitazone or GW1929, PPAR-gamma agonists or GW9662, PPAR-gamma antagonist and then cells were co-treated with high glucose (25mM) for 48h for detection of ICAM-1 expression by Western blot or luciferase assay. The involvement of AMPK on PPAR-gamma and ICAM-1 expressions was tested using pharmacological inducer or inhibitor, as well as transient transfection with AMPK-DN vector. RESULTS: CO derived from CORM-2 down-regulated ICAM-1 expression induced by high glucose. CORM-2 induced the activity of PPAR-gamma at 24h, and AMPK from 5min to 3h. PPAR-gamma agonists significantly suppressed ICAM-1 expression, whereas in the presence of antagonist (GW9662) CORM-2 failed to inhibit ICAM-1. Thus inhibition of ICAM-1 was dependent on activation of PPAR-gamma. Transfection with AMPK-DN or AMPK inhibitor resulted in attenuation of inducible effect of CORM-2 on PPAR-gamma and subsequently suppressive effect on ICAM-1 expression. CONCLUSION: Our results indicate that PPAR-gamma and AMPK pathways activated by CO are required for attenuation of ICAM-1 expression induced by high glucose. Thus, this study highlights a new property for CO derived from CORM-2 as anti-atherogenic drug for diabetic patients.

The anti-diabetic effect of anthocyanins in streptozotocin-induced diabetic rats through glucose transporter 4 regulation and prevention of insulin resistance and pancreatic apoptosis.

Hyperglycemia, abnormal lipid and antioxidant profiles are the most usual complications in diabetes mellitus. Thus, in this study, we investigated the anti-diabetic and anti-oxidative effects of anthocyanins (ANT) from black soybean seed coats in streptozotocin (STZ)-induced diabetic rats. The administration of ANT markedly decreased glucose levels and improved heart hemodynamic function (left ventricular end diastolic pressure, +/-dp/dt parameters). ANT not only enhanced STZ-mediated insulin level decreases, but also decreased the triglyceride levels induced by STZ injection in serum. Diabetic rats exhibited a lower expression of glucose transporter 4 proteins in the membrane fractions of heart and skeletal muscle tissues, which was enhanced by ANT. In addition, ANT activated insulin receptor phosphorylation, suggesting an increased utilization of glucose by tissues. Moreover, ANT protected pancreatic tissue from STZ-induced apoptosis through regulation of caspase-3, Bax, and Bcl-2 proteins. Furthermore, ANT significantly suppressed malondialdehyde levels and restored superoxide dismutase and catalase activities in diabetic rats. Interestingly, the observed effects of ANT were superior to those of glibenclamide. Taken together, ANT from black soybean seed coat have anti-diabetic effects that are due, in part, to the regulation of glucose transporter 4 and prevention of insulin resistance and pancreatic apoptosis, suggesting a possible use as a drug to regulate diabetes.

Anthocyanins from black soybean seed coats stimulate wound healing in fibroblasts and keratinocytes and prevent inflammation in endothelial cells.

Wound healing is a complex process that includes inflammation, tissue formation, and remodeling. While wound healing is accompanied by inflammatory reactions, chronic inflammation impairs acute wound healing. In this study, we investigated whether anthocyanins from black soybean seed coats could stimulate wound healing while preventing excessive inflammation. At 24h of treatment with anthocyanins, fibroblasts showed a significant increase in migration at 100 microg/mL whereas the migration of keratinocytes increased significantly at 50 and 100 microg/mL compared to control. Treatment of anthocyanins for 48 h significantly stimulated the migration of both human dermal fibroblasts and keratinocytes at 50 and 100 microg/mL concentrations. Treatment of cells with anthocyanins stimulated wound-induced VEGF production in fibroblasts and keratinocytes. However, anthocyanins inhibited ROS accumulation and VEGF production in TNF-alpha-stimulated endothelial cells. Furthermore, treatment of anthocyanins reduced, in a dose-dependent manner, the adhesion of inflammatory monocytes to endothelial cells. Anthocyanins also blocked both the translocation of nuclear factor-kappa B (NF-kappaB) p65 into the nucleus and the phosphorylation of the inhibitory factor kappaBalpha (IkappaBalpha). Thus, treatment with anthocyanins from black soybean seed coats may be a potential therapeutic strategy to promote wound healing and to prevent inflammation in a persistent inflammatory condition.

Anthocyanins from black soybean seed coats preferentially inhibit TNF-alpha-mediated induction of VCAM-1 over ICAM-1 through the regulation of GATAs and IRF-1.

Adhesion molecules have a key role in pathological inflammation. Thus, we investigated the effect of anthocyanins on the induction of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by TNF-alpha and the possible molecular mechanisms by which anthocyanins differentially regulate ICAM-1 and VCAM-1 expression. Stimulation of cells with TNF-alpha increased ICAM-1 and VCAM-1 expression, and pretreatment with anthocyanins inhibited VCAM-1 expression, but not ICAM-1 expression. We found that IRF-1 and GATAs, especially GATA-4 and -6, were involved in the TNF-alpha-mediated expression of VCAM-1 but not ICAM-1, and anthocyanins decreased nuclear levels of GATA-4 and GATA-6 as well as IRF-1. Moreover, pretreatment with a Jak/STAT inhibitor decreased TNF-alpha-induced VCAM-1 expression and nuclear GATA-4, GATA-6, and IRF-1 levels. Furthermore, anthocyanins efficiently inhibited the phosphorylation of STAT-3. This suggests that anthocyanins differentially regulate TNF-alpha-mediated expression of VCAM-1 and ICAM-1 through modulation of the GATA and IRF-1 binding activity via Jak/STAT-3 activation.