A large number of β-adrenergic receptor (β-AR) agonists and antagonists are widely used in the treatment of cardiovascular diseases and other diseases. Nonetheless, it remains unclear whether these commonly used β-AR drugs can activate downstream β- arrestin-biased signaling pathways. The objective of this study was to investigate β-arrestin2 recruitment effects of β-AR agonists and antagonists that were commonly used in clinical practice. We used TANGO (transcriptional activation following arrestin translocation) assay to detect the β-arrestin2 recruitment by β-AR ligands in HEK293 cell line (HTLA cells) stably transfected with tetracycline transactivator protein (tTA) dependent luciferase reporter and β-arrestin2-TEV fusion gene. Upon activation of β-AR by a β-AR ligand, β-arrestin2 was recruited to the C terminus of the receptor, followed by cleavage of the G protein-coupled receptors (GPCRs) fusion protein at the TEV protease-cleavage site. The cleavage resulted in the release of tTA, which, after being transported to the nucleus, activated transcription of the luciferase reporter gene. The results showed that β-AR non-selective agonists epinephrine, noradrenaline and isoprenaline all promoted β-arrestin2 recruitment at β1-AR and β2-AR. β1-AR selective agonists dobutamine and denopamine both promoted β-arrestin2 recruitment at β1-AR. β2-AR selective agonists procaterol and salbutamol promoted β-arrestin2 recruitment at β2-AR. β-AR non-selective antagonists alprenolol and pindolol promoted β-arrestin2 recruitment at β1-AR. β1-AR selective antagonists celiprolol and bevantolol showed β-arrestin2 recruitment at β1-AR. β2-AR selective antagonists butoxamine showed β-arrestin2 recruitment at β1-AR. These results provide some clues for the potential action of β-AR drugs, and lay a foundation for the screening of β-arrestin-biased β-AR ligands.
Humans ; beta-Arrestin 2/metabolism* ; HEK293 Cells ; Adrenergic beta-Agonists/pharmacology* ; Isoproterenol/pharmacology* ; Receptors, Adrenergic, beta-2/metabolism* ; Norepinephrine/pharmacology*

Alleles ; General Surgery ; methods ; Genetic Variation ; Humans ; Hypotension ; drug therapy ; Receptors, Adrenergic, beta-2 ; genetics ; metabolism ; Vasoconstrictor Agents ; administration & dosage

OBJECTIVETo investigate the significance of beta-adrenergic receptor 2 (beta2-AR) and vascular endothelial growth factor-2 (VEGFR-2) in the occurrence and development of infantile hemangioma through detecting the expression of beta2-AR and VEGFR-2 in the different stages of infantile hemangiomas.

METHODSAccording to the Mulliken's classification standard, we classified the specimens as proliferating group (32 cases), involuting group (17 cases) and involuted group (11 cases). Normal skin tissue surrounding the hemangioma from 7 cases were chosen as control group. The expression of beta2-AR and VEGFR-2 was detected by immunohistochemical technique in proliferating hemangioma, involuting hemangioma, involuted hemangioma. The mean optical density was measured by image analysis system (Image Pro Plus 6.0) and SPSS 16.0 software was applied for statistical analysis.

RESULTSThe expression of beta2-AR and VEGFR-2 was strongly positive in proliferating hemangioma, while positive in involuting hemangioma and weakly positive in the involuted stage. The mean optical density of each phase was 0.064 751 2 +/- 0.012 747, 0.031 6017 +/- 0.006 848,0.011 869 8 +/- 0.039 349 for beta2-AR, and 0.068 940 9 +/- 0.029 274, 0.028 445 5 +/- 0.006 396, 0.011 184 1 +/- 0.004 198 for VEGFR-2. The differences between different stages had a statistically significance (P < 0.05). Correlation analysis on the mean optical density between beta2-AR and VEGFR-2 had a statistically significance (P < 0. 05).

CONCLUSIONSBeta2-AR and VEGFR-2 may be involved in the occurrence and development of infantile hemangioma.

Child ; Child, Preschool ; Female ; Hemangioma ; metabolism ; Humans ; Infant ; Male ; Receptors, Adrenergic, beta-2 ; metabolism ; Receptors, Vascular Endothelial Growth Factor ; metabolism

OBJECTIVETo observe the effects of beta3-adrenergic receptor(beta3-AR) antagonist on myocardial uncoupling protein 2 (UCP2) expression and energy metabolism in chronic heart failure rats.

METHODSSeven weight-matched normal adult rats (control group), 18 isoproterenol (ISO) induced heat failure (HR) rats (ISO group) and 21 ISO induced heart failure rats but received specific beta3-AR inhibitor SR59230A (ISO+ SR59230A group) for 6 weeks were included in this research. At the end of the study, echocardiography was performed, the ratio of left ventricular weight and body weight (LVW/BW) was calculated. The expression of beta3-AR ad UCP2 mRNA in myocardium were detected by reverse transcription-polymerase chain reaction (RT-PCR), the UCP2 protein in myocardium were detected by Western blot. The myocardial contents of creatine phosphate (PCr) and adenosine triphosphate (ATP) were measured by high performance liquid chromatography (HPLC).

RESULTSCompared with control group, the cardiac function was significantly reduced and myocardial beta3-AR mRNA significantly increased, UCP2 mRNA and protein were also significantly increased in ISO group, this change could be attenuated by the treatment with SR59230A, and the expression of myocardial UCP2 protein negatively correlated with the ratio of PCr/ATP.

CONCLUSIONIn the chronic stage of HF, the expression of UCP2 increases, which causes myocardial energy shortage, SR59230A improves myocardia energy efficiency and cardiac function by means of suppressing the expression of UCP2.

Adrenergic Antagonists ; pharmacology ; Animals ; Energy Metabolism ; Heart Failure ; metabolism ; Ion Channels ; metabolism ; Male ; Mitochondrial Proteins ; metabolism ; Myocardium ; metabolism ; Rats ; Rats, Wistar ; Receptors, Adrenergic, beta-3 ; metabolism ; Uncoupling Protein 2

Sustained activation of &beta; adrenergic receptor (&beta;AR) leads to pathologic cardiac hypertrophy. However, the related mechanisms still remain unclear. In this study, we observe how N-acetylcysteine (NAC) affects the oxidative stress and calcium/calmodulin-dependent protein kinase II (CaMKII) expression in heart of isoproterenol (ISO)-stimulated rats, and investigate whether oxidative stress and CaMKII contribute to the development of sustained &beta;AR-stimulated cardiac hypertrophy. Healthy male Wistar rats were randomly separated into 4 groups: control (CTRL), ISO-treated (ISO), control with NAC supplement (CTRL+NAC) and ISO-treated with NAC supplement (ISO+NAC) groups (6 rats in each group). Systolic blood pressure (SBP) was measured in awake rats with the tail-cuff method every week for two weeks. Heart weight/body weight ratio (HW/BW) and HE staining were used for the detection of myocardial hypertrophy. Myocardial mitochondrial reactive oxygen species (ROS) levels were measured by DCF fluorometry. The expressions of activated-CaMKII (p-CaMKII/CaMKII) and NADPH oxidase 4 (NOX(4)) were determined by Western blot analysis. The results showed that ISO-treated (i.p., daily 3 mg/kg, 2 weeks) rats developed an obvious cardiac hypertrophy as expressed by increases of HW/BW and myocyte cross-section area. Cardiac mitochondrial ROS level was significantly enhanced in ISO group as compared to CTRL group (P < 0.05). The expressions of NOX(4) and p-CaMKII in ISO group were also up-regulated as compared to CTRL group (1.4 and 1.6 times of CTRL, respectively, P < 0.05). NAC supplement significantly suppressed the hypertrophic development of heart in ISO-stimulated rats. The cardiac mitochondrial ROS level showed a significant decrease in rats of ISO+NAC group (P < 0.05 vs ISO). In accordance with this, ISO+NAC group rats also showed marked reductions in the expressions of NOX(4) and p-CaMKII/CaMKII compared to ISO group rats (P < 0.05). There were no significant differences of the detected indices between the rats from CTRL+NAC and CTRL groups. SBP showed no differences among four groups. These results suggest that both oxidative stress and CaMKII play important roles in sustained &beta;AR-stimulated cardiac hypertrophy. NAC may suppress ISO-induced cardiac hypertrophy by down-regulating the expression of activated-CaMKII, and by reducing the level of oxidative stress originated from mitochondria and NADPH oxidase pathways.
Acetylcysteine ; pharmacology ; Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; metabolism ; Cardiomegaly ; physiopathology ; Isoproterenol ; pharmacology ; Male ; Mitochondria, Heart ; metabolism ; Myocardium ; pathology ; NADPH Oxidase 4 ; NADPH Oxidases ; metabolism ; Oxidative Stress ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Receptors, Adrenergic, beta ; metabolism

OBJECTIVETo investigate the antiobesity effect of Jueming Prescription (JMP), a Chinese herbal medicine formula, and its influence on mRNA expressions of beta3 adrenergic receptor (beta3-AR) and uncoupling protein-2 (UCP-2) in adipose tissue of diet-induced obese rats.

METHODSFifty male Sprague-Dawley rats were randomly divided into the normal control group (n =8) that was on a standard chow diet, and the obese model group (n =42) that was on a diet of high fat chow. Two weeks after the high fat diet, 29 obese rats in the obese model group were further randomly divided into 3 groups: the untreated obese model group (n =9), the metformin group (n =10, metformin 300 mg kg⁻¹ day)⁻¹, and the JMP group (n =10, JMP 4 g kg⁻¹ day⁻¹). After 8-week treatment, body weight, wet weight of visceral fat, and percentage of body fat (PBF) were measured. The levels of fasting blood glucose, serum lipids, and insulin were assessed, and insulin sensitivity index (ISI) was calculated. The adipose tissue section was stained with hematoxylin-Eosin, and the cellular diameter and quantity of adipocytes were evaluated by light microscopy. The mRNA expressions of beta3-AR and UCP-2 from the peri-renal fat tissue were determined by real-time reverse transcription polymerase chain reaction (RT-PCR).

RESULTSCompared with the obese model group, treatment with JMP resulted in significantly lower body weight, wet weight of visceral fat, PBF, and diameter of adipocytes, and significantly higher level of high-density lipoprotein cholesterol, ISI (all P<0.01), JMP increased the mRNA expressions of beta3-AR and UCP-2 from perirenal fat tissue (P <0.05, P<0.01).

CONCLUSIONSJMP could reduce body weight and adipocyte size; and the effect was associated with the up-regulation of beta3-AR and UCP-2 expressions in the adipose tissue and improvement of insulin sensitivity.

Adipocytes ; drug effects ; metabolism ; pathology ; Adiposity ; drug effects ; Animals ; Blood Glucose ; metabolism ; Body Weight ; drug effects ; Cell Size ; drug effects ; Diet, High-Fat ; Drugs, Chinese Herbal ; pharmacology ; Epididymis ; drug effects ; pathology ; Fasting ; blood ; Gene Expression Regulation ; drug effects ; Insulin ; blood ; Intra-Abdominal Fat ; drug effects ; metabolism ; pathology ; Ion Channels ; genetics ; metabolism ; Lipids ; blood ; Male ; Mitochondrial Proteins ; genetics ; metabolism ; Obesity ; blood ; genetics ; pathology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Adrenergic, beta-3 ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Uncoupling Protein 2 ; Weight Loss ; drug effects

OBJECTIVETo investigate the &beta;2-adrenoceptor (&beta;2AR)-&beta;-arrestin2-nuclear factor-κB (NF-κB) signal transduction pathway and the intervention effects of oxymatrine in a rat model of ulcerative colitis.

METHODSForty SD rats were randomly divided into four groups, which included the normal control group, the model group, the mesalazine group and the oxymatrine treatment group, with 10 rats per group. Experimental colitis induced with trinitrobenzene sulfonic acid (TNBS) was established in each group except the normal control group. The rats in the oxymatrine treatment group were treated with intramuscular injection of oxymatrine 63 mg/(kg·d) for 15 days and the rats in the mesalazine group were treated with mesalazine solution 0.5 g/(kg·d) by gastric lavage for 15 days. The rats in the normal control group and model group were treated with 3 mL water by gastric lavage for 15 days. Diarrhea and bloody stool were carefully observed. Histological changes in colonic tissue were examined on day 7 in 2 rats per group that were randomly selected. The expression of &beta;2AR, &beta;-arrestin2 and NF-κB p65 in colon tissue and spleen lymphocytes were detected with immunohistochemistry and Western immunoblotting techniques on day 16 after fasting for 24 h. Six rats died of lavage with 2 each in the normal control, the model group and the mesalazine group; and were not included in the analysis.

RESULTSThe rats in the model group suffered from looser stool and bloody purulent stool after modeling. But in the oxymatrine and mesalazine groups, looser stool and bloody purulent stool reduced after treatment. And the colonic wall in the model group was thickened and the colon length shortened. The colon mucosa was congested in multiple areas with edema, erosion, superficial or linear ulcer and scar formation, while the intestinal mucosa injury reduced in the mesalazine and oxymatrine groups (P<0.01). In colonic mucosa and in spleen lymphocytes, compared with the normal control group, the expression of NF-κBp65 were significantly increased (P<0.01) in the model group while the expressions of &beta; 2AR and &beta;-arrestin2 were significantly decreased (P<0.01). Compared with the model group, the expression of NF-κ Bp65 was significantly decreased in the mesalazine group (P<0.01) and oxymatrine treatment group (P<0.01) while the expressions of &beta;2AR and &beta;-arrestin2 were significantly increased (P<0.01). There were no statistically significant differences in the expression of &beta;2AR, &beta;-arrestin2 and NF-κBp65 between the mesalazine group and oxymatrine group (P>0.05).

CONCLUSIONSThe &beta;2AR-&beta;-arrestin2-NF-κB signal transduction pathway participated in the pathologic course of ulcerative colitis. Oxymatrine attenuated ulcerative colitis through regulating the &beta;2AR-&beta;-arrestin2-NF-κB signal transduction pathway.

Alkaloids ; pharmacology ; Animals ; Arrestins ; metabolism ; Colitis, Ulcerative ; drug therapy ; metabolism ; Colon ; drug effects ; pathology ; Intestinal Mucosa ; drug effects ; metabolism ; pathology ; Lymphocytes ; metabolism ; pathology ; Male ; NF-kappa B ; metabolism ; Quinolizines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Adrenergic, beta-2 ; metabolism ; Signal Transduction ; drug effects ; Spleen ; pathology ; beta-Arrestins

Adrenergic beta-2 Receptor Agonists ; pharmacology ; Anti-Inflammatory Agents ; pharmacology ; Asthma ; drug therapy ; physiopathology ; Chloroquine ; pharmacology ; Humans ; Myocytes, Smooth Muscle ; cytology ; drug effects ; metabolism ; Quaternary Ammonium Compounds ; pharmacology ; Receptors, Adrenergic, beta-2 ; metabolism ; Receptors, G-Protein-Coupled ; agonists ; metabolism ; Receptors, Interleukin-4 ; antagonists & inhibitors ; metabolism ; Respiratory System ; drug effects ; metabolism ; physiopathology

The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. beta2 adrenergic receptor (beta2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of beta2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of beta-arrestin, which is recruited by the phosphorylated beta2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system.
Adrenergic beta-Agonists/*pharmacology ; Aging/*drug effects ; Animals ; Epinephrine/*pharmacology ; G-Protein-Coupled Receptor Kinase 2/metabolism ; G-Protein-Coupled Receptor Kinase 3/metabolism ; Glucagon/pharmacology ; *Gluconeogenesis/drug effects ; Male ; Models, Biological ; Phosphorylation ; Rats ; Rats, Inbred F344 ; Receptors, Adrenergic, beta-2/agonists/metabolism

The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. beta2 adrenergic receptor (beta2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of beta2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of beta-arrestin, which is recruited by the phosphorylated beta2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system.
Adrenergic beta-Agonists/*pharmacology ; Aging/*drug effects ; Animals ; Epinephrine/*pharmacology ; G-Protein-Coupled Receptor Kinase 2/metabolism ; G-Protein-Coupled Receptor Kinase 3/metabolism ; Glucagon/pharmacology ; *Gluconeogenesis/drug effects ; Male ; Models, Biological ; Phosphorylation ; Rats ; Rats, Inbred F344 ; Receptors, Adrenergic, beta-2/agonists/metabolism