Urotensin II induces interleukin 8 expression in human umbilical vein endothelial cells

Functional effects of urotensin-II on intracellular pH regulators in human radial artery smooth muscle cells

The regulation of intracellular pH (pH_i) plays a vital role in various cellular functions. We previously demonstrated that three different acid extruders, the Na⁺-H⁺ exchanger (NHE), Na⁺-HCO₃^- co-transporter (NBC) and H⁺-linked monocarboxylate transporter (MCT), functioned together in cultured human radial artery smooth muscle cells (HRASMCs). However, the functions of acid-loading transporters in HRASMCs remain poorly understood. Urotensin II (U-II), one of the most potent vasoconstrictors, is highly expressed in many cardiovascular diseases. The aim of this present study was to determine the concentration effect of U-II (3 pM∼100 nM) on the functional activity of pH_i regulators in HRASMCs. Cultured HRASMCs were derived from segments of human radial arteries obtained from patients undergoing bypass grafting. Changes in pH_i recovery due to intracellular acidification and alkalization induced by NH₄Cl prepulse and Na-acetate prepulse, respectively, were detected by microspectrofluorimetry with the pH-sensitive fluorescent dye BCECF. Our present study showed that (a) U-II increased the activity of NHE in a concentration-dependent manner but did not change that of NBC or MCT or resting pH_i, (b) the Cl^--OH^- exchanger (CHE) facilitated base extrusion, and (c) U-II induced a concentration-dependent increase in the activity of CHE. In conclusion, for the first time, our results highlight a concentration-dependent increase in the activity of NHE and CHE, but not NBC and MCT, induced by U-II in HRASMCs.

Isoorientin Decreases Cell Migration via Decreasing Functional Activity and Molecular Expression of Proton-Linked Monocarboxylate Transporters in Human Lung Cancer Cells

Aggressive tumor cells mainly rely on glycolysis, and further release vast amounts of lactate and protons by monocarboxylate transporter (MCT), which causes a higher intracellular pH (pH_i) and acidic extracellular pH. Isoorientin, a principle flavonoid compound extracted from several plant species, shows various pharmacological activities. However, effects of isoorientin on anticancer and MCT await to explore in human lung cancer cells. Human lung cancer tissues were obtained from cancer patients undergoing surgery, while the human lung adenocarcinoma cells (A549) were bought commercially. Change of pH_i was detected by microspectrofluorometry method with a pH-sensitive fluorescent dye, BCECF. MTT and wound-healing assay were used to detect the cell viability and migration, respectively. Western blot techniques and immunocytochemistry staining were used to detect the protein expression. Our results indicated that the expression of MCTs1/4 and CD147 were upregulated significantly in human lung tissues. In experiments of A549 cells, under HEPES-buffer, the resting pH_i was 7.47, and isoorientin (1-300μM) inhibited functional activity of MCT concentration-dependently (up to -42%). Pretreatment with isoorientin (3-100μM) for 24h, MCT activity and cell migration were significantly inhibited (-25% and -40%, respectively), while the cell viability was not affected. Moreover, the expression of MCTs1/4, CD147, and matrix metalloproteinase (MMP) 2/9 were significantly down regulated. In summary, MCTs1/4 and CD147 are significantly upregulated in human lung adenocarcinoma tissues, and isoorientin inhibits cells-migration by inhibiting activity/expression of MCTs1/4 and MMPs2/9 in human lung cancer cells. These novel findings suggest that isoorientin could be a promising pharmacological agent for lung cancer.

Cafestol and Kahweol: A Review on Their Bioactivities and Pharmacological Properties

Cafestol and kahweol are natural diterpenes extracted from coffee beans. In addition to the effect of raising serum lipid, in vitro and in vivo experimental results have revealed that the two diterpenes demonstrate multiple potential pharmacological actions such as anti-inflammation, hepatoprotective, anti-cancer, anti-diabetic, and anti-osteoclastogenesis activities. The most relevant mechanisms involved are down-regulating inflammation mediators, increasing glutathione (GSH), inducing apoptosis of tumor cells and anti-angiogenesis. Cafestol and kahweol show similar biological activities but not exactly the same, which might due to the presence of one conjugated double bond on the furan ring of the latter. This review aims to summarize the pharmacological properties and the underlying mechanisms of cafestol-type diterpenoids, which show their potential as functional food and multi-target alternative medicine.

Cafestol Activates Nuclear Factor Erythroid-2 Related Factor 2 and Inhibits Urotensin II-Induced Cardiomyocyte Hypertrophy

Through population-based studies, associations have been found between coffee drinking and numerous health benefits, including a reduced risk of cardiovascular disease. Active ingredients in coffee have therefore received considerable attention from researchers. A wide variety of effects have been attributed to cafestol, one of the major compounds in coffee beans. Because cardiac hypertrophy is an independent risk factor for cardiovascular events, this study examined whether cafestol inhibits urotensin II (U-II)-induced cardiomyocyte hypertrophy. Neonatal rat cardiomyocytes were exposed only to U-II (1 nM) or to U-II (1 nM) following 12-h pretreatment with cafestol (1-10 μ M). Cafestol (3-10 μ M) pretreatment significantly inhibited U-II-induced cardiomyocyte hypertrophy with an accompanying decrease in U-II-induced reactive oxygen species (ROS) production. Cafestol also inhibited U-II-induced phosphorylation of redox-sensitive extracellular signal-regulated kinase (ERK) and epidermal growth factor receptor transactivation. In addition, cafestol pretreatment increased Src homology region 2 domains-containing phosphatase-2 (SHP-2) activity, suggesting that cafestol prevents ROS-induced SHP-2 inactivation. Moreover, nuclear factor erythroid-2-related factor 2 (Nrf2) translocation and heme oxygenase-1 (HO-1) expression were enhanced by cafestol. Addition of brusatol (a specific inhibitor of Nrf2) or Nrf2 siRNA significantly attenuated cafestol-mediated inhibitory effects on U-II-stimulated ROS production and cardiomyocyte hypertrophy. In summary, our data indicate that cafestol prevented U-II-induced cardiomycyte hypertrophy through Nrf2/HO-1 activation and inhibition of redox signaling, resulting in cardioprotective effects. These novel findings suggest that cafestol could be applied in pharmacological therapy for cardiac diseases.

Urotensin II: an inflammatory cytokine

Urotensin II (UII) is a polypeptide molecule with neurohormone-like activity. It has been confirmed that UII is widely distributed in numerous organs of different animal species from fish to mammals, including humans. The UII receptor is orphan G-protein coupled receptor 14, also known as UT. The tissue distribution of UII and UT is highly consistent, and their expression may be regulated by autocrine and paracrine mechanisms. In the body, UII has many physiological and pathophysiological activities, such as vasoconstrictor and vasodilatory actions, cell proliferation, pro-fibrosis, neuroendocrine activity, insulin resistance, and carcinogenic and inflammatory effects, which have been recognized only in recent years. In fact, UII is involved in the process of inflammatory injury and plays a key role in the onset and development of inflammatory diseases. In this paper, we will review the roles UII plays in inflammatory diseases.

Cafestol Inhibits Cyclic-Strain-Induced Interleukin-8, Intercellular Adhesion Molecule-1, and Monocyte Chemoattractant Protein-1 Production in Vascular Endothelial Cells

Moderate coffee consumption is inversely associated with cardiovascular disease mortality; however, mechanisms underlying this causal effect remain unclear. Cafestol, a diterpene found in coffee, has various properties, including an anti-inflammatory property. This study investigated the effect of cafestol on cyclic-strain-induced inflammatory molecule secretion in vascular endothelial cells. Cells were cultured under static or cyclic strain conditions, and the secretion of inflammatory molecules was determined using enzyme-linked immunosorbent assay. The effects of cafestol on mitogen-activated protein kinases (MAPK), heme oxygenase-1 (HO-1), and sirtuin 1 (Sirt1) signaling pathways were examined using Western blotting and specific inhibitors. Cafestol attenuated cyclic-strain-stimulated intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein- (MCP-) 1, and interleukin- (IL-) 8 secretion. Cafestol inhibited the cyclic-strain-induced phosphorylation of extracellular signal-regulated kinase and p38 MAPK. By contrast, cafestol upregulated cyclic-strain-induced HO-1 and Sirt1 expression. The addition of zinc protoporphyrin IX, sirtinol, or Sirt1 silencing (transfected with Sirt1 siRNA) significantly attenuated cafestol-mediated modulatory effects on cyclic-strain-stimulated ICAM-1, MCP-1, and IL-8 secretion. This is the first study to report that cafestol inhibited cyclic-strain-induced inflammatory molecule secretion, possibly through the activation of HO-1 and Sirt1 in endothelial cells. The results provide valuable insights into molecular pathways that may contribute to the effects of cafestol.

Mxi1-0 regulates the growth of human umbilical vein endothelial cells through extracellular signal-regulated kinase 1/2 (ERK1/2) and interleukin-8 (IL-8)-dependent pathways

Mxi1 plays an important role in the regulation of cell proliferation. Mxi1-0, a Mxi1 isoform, has a different N-terminal amino acid sequence, intracellular location and expression profile from Mxi1. However, the precise role of Mxi1-0 in cell proliferation and the molecular mechanism underlying its function remain poorly understood. Here, we showed that Mxi1-0 suppression decreased the proliferation of human umbilical vein endothelial cells (HUVECs) along with cell accumulation in the G2/M phase. Mxi1-0 suppression also significantly decreased the expression and secretion of interleukin (IL-8). Neutralizing IL-8 in conditioned medium (CM) from Mxi1-0-overexpressed HUVECs significantly eliminated CM-induced proliferation of HUVECs. In addition, Mxi1-0 suppression significantly decreased the activity of MAP kinase ERK1/2. Treatment of HUVECs with U0126, an ERK1/2 signaling inhibitor, attenuated autocrine production of IL-8 induced by Mxi1-0 overexpression. On the other hand, Mxi1-0 overexpression-induced IL-8 increased the level of phosphorylated ERK1/2 in HUVECs, and such increasing was diminished in cells incubated with CM, which neutralized with anti-IL-8 antibody. Taken together, our results suggest that Mxi1-0 regulates the growth of HUVECs via the IL-8 and ERK1/2 pathways, which apparently reciprocally activate each other.

miR-22 contributes to endosulfan-induced endothelial dysfunction by targeting SRF in HUVECs

microRNAs (miRNAs) function in the posttranscriptional gene regulation, providing new insights into the epigenetic mechanism of toxicity induced by environmental pollutants. miR-22 was discovered to regulate cell proliferation and apoptosis in response to environmental toxicants. We have reported that endosulfan can cause endothelial toxicity in human umbilical vein endothelial cells (HUVECs). In the present study, we investigated the involvement of miR-22 in endosulfan-induced endothelial dysfunction. The expression level of miR-22 was increased in a dose-dependent manner by endosulfan exposure. Overexpression of miR-22 induced apoptosis and inflammation in HUVECs. Anti-miR-22 transfection significantly attenuated the increase in the percentage of apoptotic cells, caspase-3 activity and Interleukin (IL)-6, 8 mRNA levels in endosulfan-exposed HUVECs. Luciferase reporter assay confirmed that SRF and STAG2 were novel direct targets of miR-22. Endosulfan decreased mRNA expression of both SRF and STAG2, but only suppressed protein expression of SRF. Knockdown of SRF via siRNAs resulted in apoptosis and inflammation whereas STAG2 siRNAs only caused abnormal mitosis in HUVECs. Taken together, these findings will shed light on the role and mechanism of miR-22 in endosulfan-induced endothelial dysfunction via SRF in HUVECs.

Inhibition of cell growth and induction of inflammation by endosulfan in HUVEC-C cells

Endosulfan is one of the organochlorine pesticides. It has been associated with a wide range of adverse health effects. However, it is unknown whether endosulfan causes endothelial dysfunction. In the present study, we investigated the effects of endosulfan on human vascular endothelial cells. We exposed human umbilical vein endothelial cells (HUVEC-C) to varying concentrations of endosulfan for 48 h. The results showed that endosulfan lowered cell viability and inhibited cell proliferation in a dose-dependent manner. Flow cytometric analysis showed that endosulfan at 60 μM induced G1 cell cycle arrest, a response attributed to down-regulation of CDK6 and pRb dephosphorylation. We observed that endosulfan at 40 and 60 μM induced a considerable percentage of cells to undergo apoptosis, as detected by Annexin-V binding assays. Endosulfan reduced mitochondrial transmembrane potential, leading to the release of cytochrome c into the cytoplasm; meanwhile, endosulfan also inhibited the mRNA expression level of survivin, which resulted in the activation of caspase-3. These results indicated that the intrinsic mitochondria-mediated pathway was involved in apoptotic process. Exposure to endosulfan increased the secretion and mRNA expression levels of inflammation factors interleukin (IL)-6 and IL-8, suggesting that endosulfan could cause inflammation. Overall, these findings suggested that endosulfan is toxic to HUVEC-C cells, resulting in endothelial dysfunction. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1785-1795, 2016.

Tanshinone IIA Induces Heme Oxygenase 1 Expression and Inhibits Cyclic Strain-Induced Interleukin 8 Expression in Vascular Endothelial Cells

Tanshinone IIA is the main effective component of Salvia miltiorrhiza, known as “Danshen,” which has been used in many therapeutic remedies in traditional Chinese medicine. However, the direct effects of tanshinone IIA on vascular endothelial cells have not yet been fully described. In the present study, we demonstrated that tanshinone IIA increased heme oxygenase-1 (HO-1) expression in human umbilical vein endothelial cells. Western blot analyses and experiments with specific inhibitors indicated tanshinone IIA enhanced HO-1 expression through the activation of phosphoinositide 3-kinase (PI3K)/Akt and the subsequent induction of nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation. In addition, tanshinone IIA inhibited cyclic strain induced interleukin-8 (IL-8) expression. HO-1 silencing significantly abrogated the repressive effects of tanshinone IIA on strain-induced IL-8 expression, which suggests HO-1 has a role in mediating the effects of tanshinone IIA. This study reports for the first time that tanshinone IIA inhibits cyclic strain-induced IL-8 expression via the induction of HO-1 in endothelial cells, providing valuable new insight into the molecular pathways that may contribute to the effects of tanshinone IIA.

Gene expression profiling of DMU-212-induced apoptosis and anti-angiogenesis in vascular endothelial cells

CONTEXT

trans-3,4,5,4'-Tetramethoxystilbene (DMU-212), an derivative of resveratrol, shows strong antiproliferative activities against many cancer cells. In our previous study, we demonstrated that DMU-212 possesses potent proapoptosis and antiangiogenesis effects on vascular endothelial cells (VECs), which made it a promising agent for the treatment of angiogenesis-related diseases.

OBJECTIVE

We studied the gene expression profile of DMU-212-treated VECs to gain further insight into the mechanisms by which DMU-212 exerts its potent pro-apoptosis and antiangiogenesis effects.

MATERIALS AND METHODS

The potential changes in the gene expression of VECs incubated with DMU-212 were identified and analyzed using the Affymetrix HG-U133 Plus 1.0 array. In addition, the gene expression profile was validated by quantitative real-time PCR (qRT-PCR) analysis for seven of those altered genes.

RESULTS AND CONCLUSION

DMU-212 was found to regulate a diverse range of genes, including cytokines (IL8, selectin E, MPZL2, EGR1, CCL20, ITGB8, CXCL1, VCAM1, KITLG, and AREG), transport proteins (TRPC4, SLC41A2, SLC17A5, and CREB5), metabolism (CYP1B1, CYP1A1, PDK4, CSNK1G1, MVK, TCEB3C, and CDKN3), enzymes (RAB23, SPHK1, CHSY3, PLAU, PLA2G4C, and MMP10), and genes involved in signal transduction (TMEM217, DUSP8, and SPRY4), chromosome organization (HIST1H2BH and GEM), cell migration and angiogenesis (ERRFI1, HBEGF, and NEDD9), and apoptosis (TNFSF15, TNFRSF9, CD274, BCL2L11, BIRC3, TNFAIP3, and TIFA), as well as other genes with unknown function (PGM5P2, SNORD1142, LOC151760, KRTAP5-2, C1orf110, SNORA14A, MIR31, C2CD4B, SCARNA4, C2orf66, SC4MOL, LOC644714, and LOC283392). This is the first application of microarray technique to investigate and analyze the profile of genes regulated by DMU-212 in VECs. Our results lead to an increased understanding of the signaling pathways involved in DMU-212-induced apoptosis and antiangiogenesis.

Urotensin II upregulates migration and cytokine gene expression in leukocytes of the African clawed frog, Xenopus laevis

Urotensin II (UII) exhibits diverse physiological actions including vasoconstriction, locomotor activity, osmoregulation, and immune response via the UII receptor (UTR) in mammals. However, in amphibians the function of the UII-UTR system remains unknown. In the present study, we investigated the potential immune function of UII using leukocytes isolated from the African clawed frog, Xenopus laevis. Stimulation of male frogs with lipopolysaccharide increased mRNA expression of UII and UTR in leukocytes, suggesting that inflammatory stimuli induce activation of the UII-UTR system. Migration assays showed that both UII and UII-related peptide enhanced migration of leukocytes in a dose-dependent manner, and that UII effect was inhibited by the UTR antagonist urantide. Inhibition of Rho kinase with Y-27632 abolished UII-induced migration, suggesting that it depends on the activation of RhoA/Rho kinase. Treatment of isolated leukocytes with UII increased the expression of several cytokine genes including tumor necrosis factor-α, interleukin-1β, and macrophage migration inhibitory factor, and the effects were abolished by urantide. These results suggest that in amphibian leukocytes the UII-UTR system is involved in the activation of leukocyte migration and cytokine gene expression in response to inflammatory stimuli.

Effects of urotensin II on intracellular pH regulation in cultured human internal mammary artery smooth muscle cells

The Na(+)-H(+) exchanger (NHE) and the Na(+)-HCO3(-) co-transporter (NBC) have been confirmed as two major active acid extruders in many mammalian cells. Whether the NHE and NBC functional co-exist in human internal mammary artery smooth muscle cells (HIMASMCs) remains unclear. The aims of the present study were to investigate the acid-extruding mechanisms and to explore the effects of urotensin-II (U-II), a powerful vasoconstrictor, on pHi regulators in HIMASMCs. We investigated the changes of pHi by BCECF-fluorescence in HIMASMCs. We found that (a) two Na(+)-dependent acid extruders, i.e. NHE and NBC, functionally co-exist; (b) U-II (3-100 nM) induced a concentration-dependent intracellular acidosis; and (c) U-II (3-100 nM) caused a concentration-dependent increase on NHE activity, while decrease on NBC activity. In summary, we demonstrate for the first time that two acid-extruders, NHE and NBC, functionally co-exist in HIMASMCs. Moreover, U-II induces a concentration-dependent intracellular acidosis through the balanced effect of its effect on increasing NHE activity and decreasing NBC activity.