Role of beta-2 adrenergic receptor polymorphism (rs1042714) on body weight and glucose metabolism response to a meal-replacement hypocaloric diet

OBJECTIVES

The beta-2 adrenergic receptor (ADRB2) is involved in energy balance regulation. The objective of our study was to evaluate the role of the rs1042714 genetic variant of ADRB2 gene on weight loss, body composition, and metabolic changes secondary to partial meal replacement (pMR) hypocaloric diet in women with obesity.

METHODS

We conducted an interventional study in 95 premenopausal women with body mass index ≥ 35 kg/m2. The subjects received two intakes per day of a normocaloric hyperproteic formula during 12 wk of a pMR diet. Body weight, body mass index, fat mass, waist circumference, lipid profile, fasting insulin levels, and homeostasis model assessment for insulin resistance were determined. All patients were genotyped rs1042714 and evaluated in a dominant model (CC versus CG + GG).

RESULTS

Genotype frequencies were 31 (37.3%), 38 (45.8%), and 14 (16.9%) for the CC, CG, and GG genotypes, respectively. We found significant interaction effects between ADRB2 variant and pMR-induced changes (CC versus CG + GG) on body weight (-7.1 ± 0.3 versus -13.5 ± 0.5 kg; P = 0.03), body mass index (-0.9 ± 0.1 versus -1.2 ± 0.2 kg/m2; P = 0.03), fat mass (-4.9 ± 0.5 versus -10.2 ±1.2 kg; P = 0.01), waist circumference (-5.1 ± 0.2 versus -10.1 ± 1.9 cm; P = 0.03), glucose (-5.1 ± 1.3 versus -12.5 ± 2.5 mg/dL; P = 0.03), total cholesterol (-18.1 ± 9.3 versus -33.5 ± 4.5 mg/dL; P = 0.03), low-density lipoprotein cholesterol (-9.1 ± 5.3 versus -24.5 ± 4.1 mg/dL; P = 0.04), triacylglycerol levels (-6.1 ± 5.3 versus -31.5 ± 9.5 mg/dL; P = 0.04), fasting insulin levels (-1.8 ± 0.3 versus -6.3 ± 0.5 IU/L; P = 0.03), and homeostasis model assessment for insulin resistance (-0.6 ± 0.3 versus -1.9 ± 0.5 U; P = 0.03). The odds ratio to improve alteration in glucose metabolism adjusted by age and weight loss throughout the study was 0.26 (95% CI, 0.07-0.95; P = 0.02) in G allele carriers.

CONCLUSIONS

The G allele of rs1042714 predicts the magnitude of weight loss resulting from a pMR diet. These adiposity improvements produce a better improvement of insulin resistance and percentage of impaired glucose metabolism in G allele carriers.

Regulation of T Helper Cell Type 2 Immune Response by Controlling Beta-2 Adrenergic Receptor in Dendritic Cells of Patients with Allergic Rhinitis

INTRODUCTION

Allergic diseases are mediated by T helper cell type 2 (Th2) cells, which are differentiated by dendritic cells (DCs). Recently, it was reported that cAMP concentration in DCs is important for inducing allergic responses. However, the regulatory function of cAMP in DCs in Th2 immune responses is unclear. It was hypothesized that the regulation of G protein-coupled receptors (GPCRs) to increase cAMP levels in DCs would reduce Th2 immune responses.

METHODS

Human DCs from patients with allergic rhinitis (AR) and from healthy controls were subjected to next-generation sequencing (NGS) to identify potential GPCR. To investigate the functions of GPCR agonists, the in vitro co-culture experiment that THP-1 cells were differentiated into DCs and cultured with human CD4+ T-cells and an AR animal in vivo model were used.

RESULTS

Among the GPCRs, the beta-2 adrenergic receptor (ADRB2) of allergic DCs was significantly increased by NGS analysis. The expression of ADRB2 was also increased in Der p 1-treated DCs, which was reduced by treatment with the ADRB2 agonist salbutamol. Salbutamol treatment induced cAMP production in THP-1 derived DCs. In an in vitro co-culture experiment, salbutamol-treated DCs reduced the secretion of Th2 cytokine. In an in vivo AR animal experiment, salbutamol-administered mice showed reduced allergic behavior and Th2 cytokine expression in the nasal mucosa.

CONCLUSIONS

The regulation of ADRB2 with salbutamol alleviated the allergic response in vitro DC-T cell co-culture and in vivo AR animal models, suggesting that ADRB2 is a therapeutic target for AR and that ADRB2 agonists may be a promising medication for AR.

Beta-2 Adrenergic Receptor Gene Expression in HER2-Positive Early-Stage Breast Cancer Patients: A Post-hoc Analysis of the NCCTG-N9831 (Alliance) Trial

BACKGROUND

Beta-2 adrenergic receptor (ß2AR) modulates immune activation and may enhance trastuzumab activity. We assessed the impact of ß2AR gene (ADRB2) expression on the outcomes of patients with HER2-positive early-stage breast cancer enrolled on the NCCTG-N9831 trial.

PATIENTS AND METHODS

This is a post-hoc analysis of the NCCTG-N9831 trial, which compared chemotherapy (arm A) versus chemotherapy plus trastuzumab (arms B&C) as adjuvant treatment of patients with HER2-positive early-stage breast cancer, with disease-free survival (DFS) as primary endpoint. Gene expression levels retrieved by DASL assay were used to classify patients as ADRB2-high or ADRB2-low. Hazard ratios (HRs) were calculated by a Cox proportional model adjusted for prognostic variables and ADRB2 expression. Correlations between ADRB2 expression and stromal tumor-infiltrating lymphocyte (TIL) levels were assessed with Pearson coefficient. A multivariable Cox regression model with interaction term was performed to assess the interaction between ADRB2 expression and treatment arm; and ADRB2 expression and a 8-gene signature previously shown to predict trastuzumab benefit.

RESULTS

Overall, 1,282 patients were included (ADRB2-high [N = 944] / ADRB2-low [N = 338]). A high expression of ADRB2 was associated with a longer DFS (P = .01) in the overall population. The addition of trastuzumab to chemotherapy improved DFS only in patients with ADRB2-high tumors (P < .01). ADRB2 expression was correlated with TIL levels (r = 0.24, P < .001). No association between ADRB2 expression and the 8-gene trastuzumab benefit signature was observed (P = .32).

CONCLUSION

Our findings suggest that a high ADRB2 expression is a favorable prognostic factor and may identify patients with HER2-positive early-stage breast cancer who benefit from adjuvant trastuzumab.

TRIAL REGISTRATION

clinicaltrials.gov NCT00005970.

Effects of a β2-adrenergic receptor blocker on experimental periodontitis in spontaneously hypertensive rats

AIMS

Recent studies have reported a relationship between periodontal disease and hypertension, and previous evidence suggests that the sympathetic nervous system plays an important role in the control of bone metabolism. This study sought to evaluate the effect of the beta-2 adrenergic receptor (β2-AR) blocker butoxamine on experimental periodontitis in a rat model.

MATERIALS AND METHODS

Wistar-Kyoto and spontaneously hypertensive rats (n = 6 per group) were orally administered butoxamine 1 mg/kg/day and experimental periodontitis was induced by applying an orthodontic ligature wire. The rats were sacrificed after 4 weeks and the residual alveolar bone was measured using micro-computed tomography (micro-CT) imaging analysis software for histological analysis.

KEY FINDINGS

Micro-CT imaging analysis showed a higher ratio of residual alveolar bone, BV/TV, and Tb.N in both Wistar-Kyoto and spontaneously hypertensive rats treated with butoxamine compared with the corresponding control rats. In histological analysis, compared with the Wistar-Kyoto and spontaneously hypertensive rat control groups, the corresponding butoxamine-treated groups showed a lower ratio of attachment level, lower values of osteoclast number and surface.

SIGNIFICANCE

β2-AR blockers maintained the alveolar bone mass and attachment level by suppressing osteoclast activity. Thus, β2-AR blockers may be effective in preventing periodontitis.

Comparison of Beta-2 Adrenergic Receptor Gene Polymorphisms Between Patients with Fibromyalgia Syndrome and Healthy Controls

Objectives

This study aims to compare the beta-2 adrenergic receptor (ADRB2) gene polymorphisms of patients with fibromyalgia syndrome (FMS) with those of healthy control subjects, and to investigate the possible relationship between symptoms of FMS and polymorphisms of the ADRB2 gene.

Patients and methods

The study included 170 females (mean age 47.8±10.3 years; range, 21 to 75 years) diagnosed with FMS according to the 2010 American College of Rheumatology criteria and 170 healthy females (mean age 47.2±8.8 years; range, 20 to 72 years) as the control group. Several clinical symptoms of the participants related to FMS were questioned and recorded. The visual analog scale (VAS) and Fibromyalgia Impact Questionnaire (FIQ) scores of the fibromyalgia group were recorded. In both groups, the ADRB2 (rs1042717) single-nucleotide polymorphism was detected by way of a real-time polymerase chain reaction. The wild-type (Guanine/Guanine), the mutant type (Adenine/Adenine) and heterozygous type (Adenine/Guanine) were detected. The sample power was calculated considering the minor allele frequency.

Results

The comparison of the ADRB2 gene polymorphism between patients with FMS and the control subjects showed that the groups were similar in terms of ADBR2 gene polymorphism and genotype (p>0.05). There was no significant difference in terms of genotype when the ADRB2 gene polymorphisms in patients with FMS were compared in terms of clinical symptoms, VAS and FIQ scores (p>0.05).

Conclusion

Beta-2 adrenergic receptor (rs1042717) gene polymorphisms and genotype distribution are no different between patients with FMS and healthy individuals. ADRB2 gene polymorphisms in patients with FMS have no effect on clinical symptoms and VAS and FIQ scores. The results of the present study will light the way for future research into ADRB2 gene polymorphisms in the pathogenesis of FMS.

Biochemical evaluation and molecular docking assessment of the anti-inflammatory potential of Phyllanthus nivosus leaf against ulcerative colitis

Ulcerative colitis (UC) is an inflammation of the colon that can progress to colorectal cancer if left untreated. No medication completely cures UC and natural products are sources of alternative approaches. This study aimed to determine the anti-inflammatory potential of Phyllanthus nivosus leaf extract and fractions in a rat model of ulcerative colitis and to identify the active ingredients. UC was induced in rats by intra-rectal infusion of 1ml of 4% acetic acid (AA) in normal saline. AA exposed groups of rats were treated with 100 mg/kg bodyweight of methanol extract, hexane, ethyl-acetate and butanol fractions orally for four days. Another group received the standard drug - Dexamethasone and control rats were given distilled water only. Some biochemical changes were evaluated and the active ingredients were identified using Gas Chromatography-Mass Spectrometry (GC-MS) followed by molecular docking against interleukin-1-beta converting enzyme (Caspase-1), beta-2 adrenergic receptor (ADRB2), cyclooxygenase-2 (COX-2) and tumour necrosis factor-alpha (TNF-α). Exposure of rat colon to acetic acid significantly altered (p < 0.05) serum levels of tumour necrosis factor-alpha (TNF-α), interleukin - 6 (IL-6), nitric oxide (NO), lipid peroxidation product (malondialdehyde or MDA), reduced glutathione (GSH); and activities of superoxide dismutase (SOD) and catalase (CAT). These alterations were however restored in the rats treated with P. nivosus leaf with the ethyl-acetate fraction displaying the highest ameliorative activity. GC-MS analysis of the ethyl acetate fraction revealed the presence of 40 compounds which when subjected to molecular docking demonstrated varying degrees of binding affinities for the protein targets. Ethyl iso-allocholate demonstrated the highest binding affinity for caspase-1, cholest-22-ene-21-ol, 3,5-dehydro-6- methoxy-, pivalate for ADRB2 and TNF-α; and alpha-cadinol for COX-2. The anti-inflammatory potential of Phyllanthus nivosus leaf as a natural remedy and as a source of new drugs against ulcerative colitis is validated.

Beta-2 adrenergic receptors increase TREG cell suppression in an OVA-induced allergic asthma mouse model when mice are moderate aerobically exercised

Background

The potency of T regulatory (TREG) cells to inhibit T helper (Th)-driven immune cell responses has been linked to increased intracellular cyclic-AMP (cAMP) levels of TREG cells. In an ovalbumin (OVA)-driven allergic asthma mouse model, moderate aerobic exercise increases TREG cell function in a contact-dependent manner that leads to a significant reduction in chronic inflammation and restoration of lung function. However, the mechanism, whereby exercise increases TREG function, remains unknown and was the focus of these investigations. Exercise can communicate with TREG cells by their expression of β2-adrenergic receptors (β2-AR). Activation of these receptors results in an increase in intracellular levels of cyclic-AMP, potentially creating a potent inhibitor of Th cell responses.

Results

For the allergic asthma model, female wildtype BALB/c mice were challenged with OVA, and exercised (13.5 m/min for 45 min) 3×/week for 4 weeks. TREG cells were isolated from all mouse asthma/exercise groups, including β2-AR^−/− mice, to test suppressive function and intracellular cAMP levels. In these studies, cAMP levels were increased in TREG cells isolated from exercised mice. When β2-AR expression was absent on TREG cells, cAMP levels were significantly decreased. Correlatively, their suppressive function was compromised. Next, TREG cells from all mouse groups were tested for suppressive function after treatment with either a pharmaceutical β2-adrenergic agonist or an effector-specific cAMP analogue. These experiments showed TREG cell function was increased when treated with either a β2-adrenergic agonist or effector-specific cAMP analogue. Finally, female wildtype BALB/c mice were antibody-depleted of CD25⁺CD4⁺ TREG cells (anti-CD25). Twenty-four hours after TREG depletion, either β2-AR^−/− or wildtype TREG cells were adoptively transferred. Recipient mice underwent the asthma/exercise protocols. β2-AR^−/− TREG cells isolated from these mice showed no increase in TREG function in response to moderate aerobic exercise.

Conclusion

These studies offer a novel role for β2-AR in regulating cAMP intracellular levels that can modify suppressive function in TREG cells.

ADRB2 signaling promotes HCC progression and sorafenib resistance by inhibiting autophagic degradation of HIF1α

BACKGROUND & AIMS

Considerable evidence suggests that adrenergic signaling played an essential role in tumor progression. However, its role in hepatocellular carcinoma (HCC) and the underlying mechanisms remain unknown.

METHODS

The effect of adrenaline in hepatocarcinogenesis was observed in a classical diethylnitrosamine-induced HCC mouse model. Effects of ADRB2 signaling inhibition in HCC cell lines were analyzed in proliferation, apoptosis, colony formation assays. Autophagy regulation by ADRB2 was assessed in immunoblotting, immunofluorescence and immunoprecipitation assays. In vivo tumorigenic properties and anticancer effects of sorafenib were examined in nude mice. Expression levels of ADRB2 and hypoxia-inducible factor-1α (HIF1α) in 150 human HCC samples were evaluated by immunohistochemistry.

RESULTS

We uncovered that adrenaline promoted DEN-induced hepatocarcinogenesis, which was reversed by the ADRB2 antagonist ICI118,551. ADRB2 signaling also played an essential role in sustaining HCC cell proliferation and survival. Notably, ADRB2 signaling negatively regulated autophagy by disrupting Beclin1/VPS34/Atg14 complex in an Akt-dependent manner, leading to HIF1α stabilization, reprogramming of HCC cells glucose metabolism, and the acquisition of resistance to sorafenib. Conversely, inhibition of ADRB2 signaling by ICI118,551, or knockdown ADRB2 expression, led to enhanced autophagy, HIF1α destabilization, tumor growth suppression, and improved anti-tumor activity of sorafenib. Consistently, ADRB2 expression correlated positively with HIF1α in HCC specimens and was associated with HCC outcomes.

CONCLUSIONS

Our results uncover an important role of ADRB2 signaling in regulating HCC progression. Given the efficacy of ADRB2 modulation on HCC inhibition and sorafenib resistance, adrenoceptor antagonist appears to be a putative novel treatment for HCC and chemoresistance.

LAY SUMMARY

ADRB2 signaling played an essential role in sustaining hepatocellular carcinoma cell proliferation and survival. ADRB2 signaling negatively regulated autophagy, leading to hypoxia-inducible factor-1α stabilization, reprogramming of hepatocellular carcinoma cells glucose metabolism, and the acquisition of resistance to sorafenib. Adrenoceptor antagonist appears to be a putative novel treatment for hepatocellular carcinoma and chemoresistance.

Sympathetic Regulation of Tertiary Dentinogenesis via Beta-2 Adrenergic Receptor on Rat Odontoblasts

INTRODUCTION

Beta-2 adrenergic receptor has been found within the osteoblast membrane meditating bone remodeling. Propranolol is a sympatholytic beta antagonist commonly used as long-term medication for the management of many common diseases such as hypertension. This study was performed to verify the presence of this receptor on odontoblasts in rats and, if present, to investigate its possible association with tertiary dentinogenesis.

METHODS

Twenty male Sprague-Dawley rats (9 weeks old) were randomly assigned to 4 groups: CP0.8 group, cavity preparation + propranolol treatment (0.8 mg/day, n = 5); CP4 group, cavity preparation + propranolol treatment (4.0 mg/day, n = 7); CON group, cavity preparation + saline treatment (0.2 mL/day, n = 5); and NT group, no treatment (n = 3). Cavity preparation was performed on the mesial aspect of the maxillary first molars bilaterally. After 2 weeks, the tertiary dentinogenesis (CP0.8, CP4, and CON) was examined by hematoxylin-eosin staining, and the localization of beta-2 adrenergic receptor (NT) was examined by immunohistochemistry.

RESULTS

The beta-2 adrenergic receptor immunoreactivity was observed in the odontoblastic layer in normal rat molar dental pulp. The tertiary dentinogenesis beneath the prepared cavity was significantly higher in the rats receiving 2-week systemic administration of propranolol than in those without the propranolol treatment. The higher-dose treatment of propranolol (P < .001) presented more effective up-regulation of tertiary dentinogenesis than the lower-dose treatment (P < .01).

CONCLUSIONS

These results indicate that the sympathetic nervous system decreases tertiary dentin formation via beta-2 adrenergic receptors located on rat odontoblasts. It suggests that adrenergic beta antagonist is expected to use in the treatment of inducing tertiary dentin formation to protect dental pulp.