The correlation between pulmonary endothelin receptors and alveolar-arterial oxygen gradient (A-aDO2) in rats with hepatopulmonary syndrome was investigated. Animals were divided into 2 groups: Sham-operated (Sham) group and common bile duct ligation (CBDL) group. Arterial blood gas was evaluated by a blood gas analyzer. The concentrations of ET-1 in blood and lung tissue sample were evaluated by radioimmunoassay. The distribution and expression of two kinds of subtype receptor of ET-1, ETRA and ETRB were examined by in situ hybridization. The results showed that the level of A-aDO2 was higher in CBDL group than that in Sham group (P < 0.05). The levels of plasma and pulmonary ET-1 in CBDL group were both higher than in Sham group (P < 0.05). There was no significant difference in average A of ETRA between two groups by imaging analysis (0.21 +/- 0.06 vs 0.22 +/- 0.08, P > 0.05), while that of ETRB was higher in CBDL group than in Sham group (0.58 +/- 0.16 vs 0.28 +/- 0.07, P < 0.05). The expression of ETRB in lung was positively correlated with A-aDO2 (P < 0.05). It was concluded that the widened A-aDO2 may be related with enhancement of the expression of ETRB in lung.
Endothelin-1/metabolism ; Hepatopulmonary Syndrome/*metabolism ; Lung/*metabolism ; Oxygen/*metabolism ; Pulmonary Alveoli/*metabolism ; Rats, Wistar ; Receptor, Endothelin A/metabolism ; Receptor, Endothelin B/*metabolism

<b>AIMb>To investigate the effect of endogenous endothelin-1 (ET-1) on cardiomyocyte apoptosis induced by hypoxia and its possible mechanism.

<b>METHODSb>Cultured neonatal rat cardiomyocytes were divided into control group and ET receptor antagonist group. Control group was given DMEM only and ET receptor antagonist group was treated with ET receptor subtype A (ET(A)) receptor antagonist BQ610 and BQ123 or ET(B) receptor antagonist BQ788 and subjected to hypoxia for 24 h. The presence of apoptosis in cardiomyocytes was evaluated by TUNEL analysis and flow cytometry (FCM).

<b>RESULTSb>TUNEL analysis showed that the percentage of positive apoptotic cells in BQ610 5 micromol/L group was 13.2% +/- 3.7%, significantly lower than that in hypoxia group (24.2% +/- 2.2%, P < 0.01). FCM showed that BQ123 (0.04, 0.2 and 1.0 micromol/L) inhibited hypoxia-induced cardiomyocyte apoptosis and increased cardiomyocyte survival rate in a dose-dependent manner, while BQ788 did not show such effects.

<b>CONCLUSIONb>These findings suggest that endogenous ET-1 aggravates hypoxia-induced cardiomyocyte apoptosis and this effect is mediated through ET(A) receptor-dependent pathways.

Animals ; Animals, Newborn ; Apoptosis ; Cell Hypoxia ; Cells, Cultured ; Endothelin A Receptor Antagonists ; Endothelin B Receptor Antagonists ; Endothelin-1 ; physiology ; Myocytes, Cardiac ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley

<b>OBJECTIVEb>To study the expression of ET receptor and the apoptosis after intervened with ET receptor antagonist in androgen-independent prostate cancer.

<b>METHODSb>PC3, an androgen-independent prostate cancer cell line, was used. The expression of ETA and ETB receptor in PC3 was measured through RT-PCR. After intervened with selective ETA and ETB receptor antagonist, the apoptosis in PC3 was studied through flow cytometry and electron microscope.

<b>RESULTSb>Clear signal was obtained in PC3 for ETA receptor mRNA transcript, while the signal for ETB receptor mRNA transcript was very weak. The expression of ETA receptor mRNA was obviously reduced and the apoptosis of PC3 cell was observed after intervened with selective ETA receptor antagonist. There was no change after intervened with selective ETB receptor antagonist.

<b>CONCLUSIONb>ET-1 exerts its effects through the ETA receptor subtype and ETB receptor is silenced in PC3. The expression of ETA was reduced and the apoptosis was observed in PC3 when ETA receptor was blocked. It was dose-dependent.

Androgens ; physiology ; Apoptosis ; drug effects ; physiology ; Endothelin A Receptor Antagonists ; Endothelin B Receptor Antagonists ; Endothelin-1 ; physiology ; Humans ; In Vitro Techniques ; Male ; Neoplasms, Hormone-Dependent ; pathology ; Oligopeptides ; administration & dosage ; Peptides, Cyclic ; administration & dosage ; Piperidines ; administration & dosage ; Prostatic Neoplasms ; pathology ; physiopathology ; Receptor, Endothelin A ; metabolism ; physiology ; Receptor, Endothelin B ; metabolism ; physiology

In order to investigate the expression of endothelin receptor B (ETR-B) in human malignant melanoma (MM) cells A375 and SK-mel-1 and the proliferative effects of endothelin 3 (ET3) on A375 cells, RT-PCR was applied to detect the expression of ETR-B gene in human MM cells A375 and SK-mel-1. MTT method was used to evaluate the growth enhancing effects of ET3 on A375 cell line in vitro. The results showed that ETR-B gene was expressed in both MM A375 and SK-mel-1 cells. ET3 had stronger ability to enhance the proliferation of A375 cells in vitro in a concentration-dependent manner. It was suggested that ET3/ETR-B might play an important proliferative role in MM.
Cell Line, Tumor ; Cell Proliferation/*drug effects ; Endothelin-3/*pharmacology ; Melanoma/*metabolism ; Melanoma/*pathology ; Receptor, Endothelin B/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction

<b>BACKGROUNDb>Elastin derived peptides can regulate melanocyte precursor development. Ultraviolet irradiation, infrared radiation and heat can increase the synthesis of tropoelastin in human skin epidermis. The aim of this study was to investigate whether the over expressed tropoelastin in epidermis has some role in melanogenesis of melanocytes.

<b>METHODSb>A375 human melanoma cells were treated with different concentrations of kappa elastin for 24 hours. A375 human melanoma cells were randomly assigned to control, kappa elastin, and lactose pre-incubated groups. The cell viabilities were detected by the methyl thiazoleterazolium assay. Melanin content and tyrosinase activity in A375 melanoma cells were measured. The expressions of endothelin B receptor (ET(B)R) mRNA and c-kit mRNA in A375 melanoma cells were measured by quantative reverse transcription polymerase chain reaction.

<b>RESULTSb>Fifty µg/ml of kappa elastin significantly increased the melanin content by 56.64% compared with the control (P < 0.05). Kappa elastin increased cellular tyrosinase activity by 46.73% compared with the control at 24 hours (P < 0.05). Kappa elastin increased the expressions of ET(B)R and c-kit mRNA levels by 2.13-fold and 2.47-fold compared with the controls, respectively. When pre-incubating cells with a lactose solution (10 mmol/L), the inhibition on melanin production was 34.96% compared with the kappa elastin group (P < 0.05), tyrosinase activity was inhibited by 29.93% compared with kappa elastin group (P < 0.05), and the expressions of ET(B)R mRNA and c-kit mRNA were decreased by 1.56-fold and 0.82-fold compared with kappa elastin group, respectively.

<b>CONCLUSIONb>Kappa elastin increased the melanogenesis in A375 melanoma cells via the stimulation of tyrosinase activity and the expression of ET(B)R and c-kit. The over expressed tropoelastin produced by keratinocytes might play a role in melanogenesis of epidermal melanocytes.

Cell Line, Tumor ; Cell Survival ; drug effects ; Elastin ; pharmacology ; Humans ; Keratinocytes ; drug effects ; Melanins ; metabolism ; Melanoma ; Proto-Oncogene Proteins c-kit ; metabolism ; Receptor, Endothelin B ; metabolism

<b>OBJECTIVEb>To investigate the effect of endothelin and its receptors on ouabain-induced hypertension in rats.

<b>METHODSb>Male Sprague-Dawley (SD) rats were treated with ouabain or saline for 6 weeks and their systolic blood pressure (SBP) were recorded weekly. At the end of 2, 4 and 6 weeks, respectively, the plasma and left ventricle endothelin contents were measured by radio-immunoassay, and real-time quantitative RT-PCR was employed to determine the mRNA level of endothelin type A receptor (ETAR) and type B receptor (ETBR) in the left ventricle, and the protein expressions of ETAR and ETBR were examined by immuno-histochemistry.

<b>RESULTSb>After 4 weeks of intraperitoneal ouabain injection, the mean SBP in ouabain group increased till reaching a level significantly higher than that in the control group after 6 weeks (P<0.001). The plasma and left ventricle endothelin contents were significantly increased after 2 weeks of ouabain injection (P<0.01), and similarly, increased ETAR mRNA was observed. After 4 weeks of treatment, ETAR mRNA was increased continuously and the protein expression of ETAR upregulated in ouabain group as compared with the control group. The transcription and protein expression of ETBR were not altered by ouabain treatment.

<b>CONCLUSIONb>Before detectable blood pressure elevation occurs, endothelin concentration and ETAR can be already upregulated in ouabain-induced hypertensive rats, suggesting that endothelin might be involved in the cardiovascular effects of ouabain via an action on ETAR.

Animals ; Endothelins ; biosynthesis ; blood ; genetics ; Hypertension ; chemically induced ; genetics ; metabolism ; Immunohistochemistry ; Male ; Myocardium ; metabolism ; Ouabain ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin A ; genetics ; metabolism ; Receptor, Endothelin B ; genetics ; metabolism ; Receptors, Endothelin ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

<b>OBJECTIVEb>To investigate the effects of the epidermal growth factor on the mRNA expression of endothelin-1 and its receptors (ET(A)R, ET(B)R) in hormone refractory prostate cancer (HRPC) PC-3 cell lines.

<b>METHODSb>PC-3 cells were cultured in vitro. After the treatment with EGF, the mRNA expressions of endothelin-1, ET(A)R and ET(B)R were detected by RT-PCR in PC-3 cell lines. The levels of the mRNA expression of endothelin-1 and its receptors were examined at different time points by RT-PCR.

<b>RESULTSb>The expressions of endothelin-1 and ET(A)R mRNA but not the mRNA expression of ET(B)R was observed in PC-3 cell lines. After 24 hours of treatment with EGF, the expressions of endothelin-1 and ET(A)R in PC-3 cell lines were both up-regulated and there was significant difference (P < 0.05) between the experimental and control groups. Different expression levels of endothelin-1 and ET(A)R mRNA were noted at different time points of EGF intervention, up-regulated with the increase of treatment time, and with significant difference (P < 0.05).

<b>CONCLUSIONb>EGF can up-regulate the mRNA expressions of endothelin-1 and ET(A)R in PC-3 cell lines and play a great role in prostate cancer progression, which may offer a substructure of molecular biology for the treatment of HRPC.

Cell Line, Tumor ; Endothelin-1 ; genetics ; Epidermal Growth Factor ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; Male ; Prostatic Neoplasms ; genetics ; pathology ; RNA, Messenger ; genetics ; metabolism ; Receptor, Endothelin A ; genetics ; Receptor, Endothelin B ; genetics ; Receptors, Endothelin ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

<b>OBJECTIVEb>To study the effect of endothelin-1 (ET-1) and its antagonists on the expression of endothelin and its receptors mRNA in HSC-T6 cells.

<b>METHODSb>Cultured HSC-T6 cells were randomly divided into 7 groups: Sham control group, ET-1 group (10 nmol/L ET-1), BQ-123 group [1 micromol/L BQ-123, a selective endothelin receptor A (ETRA) antagonist], BQ-788 group [1 micromol/L BQ-788, a selective endothelin receptor B (ETRB) antagonist], ET-1 + BQ123 group (10 nmol/L ET-1 + 1 micromol/L BQ-123), ET-1 + BQ-788 group (10 nmol/L ET-1 + 1 micromol/L BQ-788) and ET-1 + BQ-788 group (10 nmol/L ET-1 + 1 micromol/L BQ-123 + 1 micromol/L BQ-788). The expression of endothelin receptor mRNA of HSC-T6 cells was determined by reverse-transcription polymerase chain reaction (RT-PCR).

<b>RESULTSb>The expression of ETRA mRNA in ET-1 + BQ123 + BQ788 and ET-1 + BQ788 group was significantly lower than ET-1 group (0.329 +/- 0.044 and 0.292 +/- 0.023 vs. 0.440 +/- 0.030 P < 0.05). Compared with ET-1 group, the expression of ETRB mRNA in ET-1 + BQ788 group was down regulated obviously (0.499 +/- 0.136 vs. 0.153 +/- 0.071, P < 0.05). There was no significant difference in ET-1 + BQ123 group and ET-1 + BQ123 + BQ788 group when compared with ET-1 group (0.499 +/- 0.136 vs. 0.496 +/- 0.103 and 0.299 +/- 0.129, P > 0.05).

<b>CONCLUSIONSb>ET-1 has no obvious effect on the expression of ETRA mRNA in HSC-T6. ET-1 may up-regulate the expression of ETRB mRNA. Act on ETRA receptor, ET-1 can inhibit the expression of ETRB mRNA.

Animals ; Cells, Cultured ; Endothelin-1 ; pharmacology ; Gene Expression Regulation ; drug effects ; Hepatocytes ; drug effects ; metabolism ; Oligopeptides ; pharmacology ; Peptides, Cyclic ; pharmacology ; Piperidines ; pharmacology ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin A ; biosynthesis ; drug effects ; genetics ; Receptor, Endothelin B ; biosynthesis ; drug effects ; genetics

To systematically clarify the effects of apolipoprotein E (aopE) and low-density lipoprotein receptor (LDLR) gene mutant on hyperlipidemia, vascular inflammation impairment and pathogenesis of atherosclerosis (AS), total RNA was isolated from fresh aortas of young apoE/LDLR double knockout (apoE(-/-)/LDLR(-/-)) and wild type (WT) mice using TRIzol reagent. Then RNA was reversely transcribed to first-strand cDNA by reverse transcriptase for reverse transcription polymerase chain reaction (RT-PCR) and real-time RT-PCR. Primer pairs were designed using primer design software according to the gene sequences available in GenBank. β-actin was used as an internal control. Then RT-PCR assay was used to analyze the expression patterns of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), nuclear factor-κB (NF-κB), granulocyte-macrophage colony-stimulating factor (GM-CSF), CD36, endothelin-1 (ET-1), toll-like receptor 2 (TLR2), monocyte chemoattractant protein-1 (MCP-1), vascular adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and platelet-derived growth factor-α (PDGF-α). SYBR Green quantitative real-time RT-PCR was used to validate gene expressions identified by RT-PCR. Blood samples were taken from the retro-orbital venous plexus, and serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) were measured by using biochemical techniques. Serum concentrations of circulating TNF-α, IL-1β and oxidized LDL (ox-LDL) were determined by ELISA. Frozen sections of aortic sinus were stained with Sudan IV to visualize intimal fatty lesions. The results showed that the relative expressions of IL-1β, GM-CSF, ET-1, TLR2, CD36, MCP-1, ICAM-1 and VCAM-1 in apoE(-/-)/LDLR(-/-) mice at the age of 1 month were higher than those in age-matched WT mice (P<0.05, P<0.01), respectively. The expressions of PDGF-α and TNF-α in apoE(-/-)/LDLR(-/-) mice at the age of 2 months were up-regulated compared to those in age-matched WT mice (P<0.05). All the expressions of target genes continued to be up-regulated (P<0.05, P<0.01) except that ET-1 expression at the age of 2 months, TLR2, VCAM-1 and ICAM-1 expressions at the age of 3 months were down-regulated to that in WT mice. NF-κB expression had no significant changes between two genotype mice at different ages. All the gene expressions kept unchanged in WT mice at different ages, except that IL-1b expressions were slightly up-regulated at the ages of 2 and 3 months. Serum levels of TC, TG, LDL, HDL, TNF-α, IL-1β and ox-LDL in apoE(-/-)/LDLR(-/-) mice at different ages were higher than those in age-matched WT mice (P<0.05, P<0.01), and were increasing with age. Primary atherosclerotic lesions were observed in 1-month old apoE(-/-)/LDLR(-/-) mice and were progressing with age. There were no lesions observed in all WT mice at different ages. The data suggest that hyperlipidemia due to apoE and LDLR gene mutant may stimulate the temporal expressions of AS-related genes and contribute to primary atherogenetic lesions and vascular inflammation impairment.
Animals ; Aorta ; metabolism ; Apolipoproteins E ; genetics ; Atherosclerosis ; genetics ; CD36 Antigens ; metabolism ; Chemokine CCL2 ; metabolism ; Endothelin-1 ; metabolism ; Gene Expression ; Granulocyte-Macrophage Colony-Stimulating Factor ; metabolism ; Hyperlipidemias ; metabolism ; Intercellular Adhesion Molecule-1 ; metabolism ; Interleukin-1beta ; blood ; metabolism ; Lipoproteins, LDL ; blood ; Mice ; Mice, Knockout ; NF-kappa B ; metabolism ; Platelet-Derived Growth Factor ; Receptors, LDL ; genetics ; Toll-Like Receptor 2 ; metabolism ; Tumor Necrosis Factor-alpha ; blood ; metabolism ; Vascular Cell Adhesion Molecule-1 ; metabolism

<b>AIMb>To determine the involvement of extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in the expression of endothelin receptor type B (ETB) during culture.

<b>METHODSb>SB386023, a specific inhibitor for ERK1/2 pathway, was used to define the intracellular signaling pathway for the upregulation of ETB receptors and sarafotoxin 6c (S6c), a selective agonist for ETB receptors, induced contraction in isolated rat superior mesenteric arteries. The contraction was recorded by a sensitive in vitro myograph and the receptor mRNA was quantified by a real-time PCR. The phosphorylated ERK1/2 proteins were analyzed by phosphoELISA assay.

<b>RESULTSb>S6c induced strong contractile responses of the artery after culture for 24 h, while there was no response to S6c in fresh vessel segments. The enhanced contractile response to S6c paralleled with an increase of mRNA for ETB receptors. The phosphorylated ERK1/2 proteins significantly increased after culture for 3 h. After co-culture with SB386023 for 24 h, S6c-induced contractions significantly decreased with reduction of Emax from (217 +/- 14) % to (127 +/- 23) % (P <0.01). This response paralleled with a decreased level of ETB receptor mRNA.

<b>CONCLUSIONb>ERK1/2 pathway was involved in the up-regulation of ETB receptors on smooth muscle cells isolated from rat mesenteric arteries during culture.

Animals ; Cells, Cultured ; Male ; Mesenteric Arteries ; cytology ; Mitogen-Activated Protein Kinase 1 ; antagonists & inhibitors ; metabolism ; Mitogen-Activated Protein Kinase 3 ; antagonists & inhibitors ; metabolism ; Muscle Contraction ; drug effects ; Muscle, Smooth, Vascular ; cytology ; metabolism ; Organ Culture Techniques ; Phosphorylation ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin B ; biosynthesis ; genetics ; Signal Transduction ; Up-Regulation ; Vasoconstrictor Agents ; pharmacology ; Viper Venoms ; pharmacology