AIMTo investigate the effect of endogenous endothelin-1 (ET-1) on cardiomyocyte apoptosis induced by hypoxia and its possible mechanism.

METHODSCultured 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).

RESULTSTUNEL 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.

CONCLUSIONThese 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

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

Three-dimensional pharmacophore models were generated for AT1 and ET(A) receptors based on highly selective AT1 and ET(A) antagonists using the program Catalyst/HipHop. Both the best pharmacophore model for selective AT1 antagonists (Hypo-AT(1)-7) and ETA antagonists (Hypo-ET(A)-1) were obtained through a careful validation process. All five features contained in Hypo-AT(1)-7 and Hypo-ET(A)-1 (hydrogen-bond acceptor (A), hydrophobic aliphatic (Z), negative ionizable (N), ring aromatic (R), and hydrophobic aromatic (Y)) seem to be essential for antagonists in terms of binding activity. Dual AT1 and ET(A) receptor antagonists (DARAs) can map to both Hypo-AT(1)-7 and Hypo-ET(A)-1, separately. Comparison of Hypo-AT(1)-7 and Hypo-ET(A)-1, not only AT1 and ET(A) antagonist pharmacophore models consist of essential features necessary for compounds to be highly active and selective toward their corresponding receptor, but also have something in common. The results in this study will act as a valuable tool for designing and researching structural relationship of novel dual AT1 and ET(A) receptor antagonists.
Angiotensin II Type 1 Receptor Blockers ; chemistry ; Drug Design ; Endothelin Receptor Antagonists ; Models, Molecular ; Molecular Conformation

AIMThe purpose of the present study is to discuss the influence of different exercise load on the concentration of ET in plasma and myocardial cells, and the activity of ETR on myocardial cell's membrane in rats.

METHODS45 male SD rats were divided into the following 5 groups randomly: Group A (control group); Group B (45 min swim group); Group C (90 min swim group); Group D (150 min swim group); Group E (acute exhaust group). After having been trained for 8 weeks, the levels of ET and activity of ETR were measured by RIA.

RESULTSThe concentrations of ET in plasma and myocardial cells of 90 min swim group were decreased significantly (P < 0.01)and 90 min swim could reduce the activity of ETR (P < 0.01). The activity of ETR was elevated significantly in 150 min swim group (P < 0.01).

CONCLUSIONModerate exercise loads can significantly ameliorate the cardiovascular function, and high exercise loads is harmful to myocardial cells.

Animals ; Endothelin-1 ; metabolism ; Male ; Myocytes, Cardiac ; metabolism ; Physical Conditioning, Animal ; physiology ; Rats ; Rats, Sprague-Dawley ; Receptor, Endothelin A ; metabolism ; Swimming

OBJECTIVETo study the expression of ET receptor and the apoptosis after intervened with ET receptor antagonist in androgen-independent prostate cancer.

METHODSPC3, 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.

RESULTSClear 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.

CONCLUSIONET-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

Waardenburg syndrome (WS) is a rare genetic disorder, including clinical features of pigmentary abnormalities of irides, skin, hair and sensorineural hearing loss and facial dysmorphism. Among the four types, WS type IV (Waardenburg-Shah syndrome) additionally represents Hirschsprung's disease. Mutations in the SOX10, END3, or EDNRB genes are known to cause WS type IV. Here, we report a 6 year-old girl who was diagnosed as WS type IV by typical clinical manifestations, including skin hypopigmentation, heterochromia of both irides, unilateral sensorineural hearing loss, mild developmental delay and Hirschsprung's disease. The diagnosis was confirmed by molecular genetic analysis of EDNRB. Two novel EDNRB mutations were identified, and each mutation was segregated from each of her parents. During the follow-up period, the patient underwent a surgery for spleen torsion and was medically managed due to recurrent enterocolitis. Also, she suffered from impaired immunity including Hirschsprung's associated enterocolitis.
Diagnosis ; Endothelins* ; Enterocolitis ; Female ; Follow-Up Studies ; Hair ; Hearing Loss, Sensorineural ; Hirschsprung Disease ; Humans ; Hypopigmentation ; Molecular Biology ; Parents ; Receptor, Endothelin B ; Receptors, Endothelin* ; Skin ; Spleen ; Waardenburg Syndrome

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

OBJECTIVETo 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.

METHODSPC-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.

RESULTSThe 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).

CONCLUSIONEGF 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

OBJECTIVETo observe the effect of electroacupuncture (EA) stimulation on the expressions of angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R), endothelin-1 (ET1), and endothelin A receptor (ETAR) mRNA in spontaneously hypertensive rat (SHR) aorta.

METHODSEighteen male SHRs were randomly divided into three groups, an SHR group, an SHR Baihui (DU 20) and Zusanli (ST 36) acupoint (SHR-AP) group, and an SHR non-acupoint (SHR-NAP) group, with 6 rats in each group. Six Wistar rats were used as a control. Rats in the SHR-AP group were stimulated by DU 20 and ST 36 acupoints, both of which were connected with EA. EA was handled one time every Monday, Wednesday and Friday, for total 24 times (8 weeks). SHRNAP rats were acupointed at a 15°angle flat into 0.5 cm to two points, which were 1 and 2 cm from rail tip separately. EA parameters were the same as the SHR-AP rats. SHR control rats and Wistar rats were fixed without EA. Real-time quantitative polymerase chain reaction (PCR) was used to measure AGT, AT1R, ET1, and ETAR mRNA expression in rat aorta.

RESULTSEA stimulation significantly reduced rat aorta vascular AGT, ET1, ETAR and AT1R mRNA expressions in the SHR-AP and SHR-NAP groups (P <0.01). Among these four genes, AT1R mRNA expression was significantly lower in the SHR-AP than in the SHR-NAP group (P <0.01).

CONCLUSIONEA could reduce the AT1R mRNA expression in SHR-AP rat aorta, indicating a potential mechanism for the hypotensive effects of EA.

Angiotensinogen ; genetics ; metabolism ; Animals ; Aorta ; metabolism ; physiopathology ; Blood Pressure ; Electroacupuncture ; Endothelin-1 ; genetics ; metabolism ; Gene Expression Regulation ; Male ; RNA, Messenger ; genetics ; metabolism ; Rats, Inbred SHR ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Receptor, Endothelin A ; genetics ; metabolism

OBJECTIVETo investigate the anti-tumor effect of the endothelin A receptor antagonist BQ123 on human prostate cancer cell line PC-3M in vitro by observing its impact on the proliferation and apoptosis of human prostate cancer cells.

METHODSThe inhibiting effect of BQ123 on the proliferation of PC-3M cells was observed by MTT assay, erosion trace test and Transwell chamber chemotaxis assay, and its induction of their apoptosis determined by Annexin V-FITC/PI staining and cytometry.

RESULTSBQ123 exhibited increased inhibition of PC-3M cells in a time-dependent manner, with inhibition rates of 22.32%, 44.88% and 64.47% at 24 h, 48 h and 72 h, respectively (P < 0.05). The migration distances of the PC-3M cells in the BQ123 group were (103.42 +/- 75.63) microm, (243.75 +/- 121.53) microm and (422.07 +/- 36.01) microm at 12 h, 24 h and 48 h, obviously lower than (162.93 +/- 19.87) microm, (317.19 +/- 43.19) microm and (692.74 +/- 40.84) microm in the control group (P < 0.05). The number of the PC-3M cells that invaded the inferior chamber in the BQ123 group was (79.2 +/- 9.58), significantly decreased as compared with (92.6 +/- 5.94) in the control (P < 0.05). The apoptosis rate of PC-3M exposed to BQ123 was (15.03 +/- 0.93)%, significantly higher than (9.38 +/- 1.37)% in the control (P < 0.05). The ratio of PC-3M cells in different cycles showed no significant differences.

CONCLUSIONBQ123 inhibits the proliferation of PC-3M cells and induces their apoptosis in vitro, which may give a new idea on the studies of prostate cancer therapies.

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Endothelin A Receptor Antagonists ; Humans ; Male ; Peptides, Cyclic ; pharmacology ; Prostatic Neoplasms