β2-AR Expression Research Articles

Abstract 4797: β3-AR blockade induces differentiation of malignant leukemia T cells in mature T lymphocytes

Abstract Acute lymphoblastic leukemia (ALL) is a genetically heterogeneous cancer that arises from diverse genetic alterations during early lymphocyte development. About 10-15% of T-cell acute lymphoblastic leukemia (T-ALL) cases occur in childhood; despite having an event-free survival (EFS) rate of 85%, relapse is the main problem of this type of cancer. Mitochondria metabolic reprogramming plays a crucial role in the development of lymphocytes both in physiological and pathological processes such as differentiation and neoplastic transformation respectively. Mitochondria are the main actors of cellular homeostasis. They use glycolysis products exploiting them in the Krebs cycle and in oxidative phosphorylation to produce energy and plays key roles in reactive oxygen species (ROS) generation, Ca2+ signaling, cell death induction, and cellular differentiation. In particular, the increase of ROS is important to reduce tumor cell viability and at the same time is involved in induction of hematopoiesis. β3-adrenoreceptors (β3-Ars) is a class of receptors associated with pro-tumoral signaling in different tumors. In this study, we first have observed the expression of β3-Ars in leukemia T cells and then we studied how the modulation of this receptors affected tumor-related pathways. The treatment with an antagonist of β3-Ars (SR59230A) induced an increase of ROS leading to lymphoblastic cells differentiation, decrease of proliferation and enhanced induction of apoptosis signaling. Overall, these results suggest that β3-Ars could be a possible target for treatment of T-ALL. Citation Format: Francesco Carrozzo, Gennaro Bruno, Claudia Masi, Alessia Boaretto, Claudio Favre, Maura Calvani. β3-AR blockade induces differentiation of malignant leukemia T cells in mature T lymphocytes. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4797.

Abstract 4808: Hypoxic HIF-1α stabilization dependent on β3-adrenoceptor localization in Ewing sarcoma

Abstract Hypoxia is a condition of oxygen deficiency which occurs in most growing solid tumors and stimulates a cascade of cell signals through a family of transcription factors named as hypoxia inducible factors (HIFs) that transactivate several regulatory genes involved in tumor proliferation. β3-adrenoceptors (β3-ARs) are involved in several hypoxic scenarios and in pathological conditions where hypoxia leads to important steps for cancer progression. Studies showed that β-AR blockade of mice suppressed hypoxia induction of renal HIF-1α accumulation, erythropoietin production, and erythropoiesis in vivo. In this work we assumed that β3-AR mediates hypoxia sensing and that it was necessary for HIF-1α stabilization thus we investigated a putative correlation between β3-AR/HIF-1α. Data showed a similar outcome of β3-ARs and HIF-1α at short time of hypoxia, and that β3-AR antagonist, SR59230A reduced HIF-1α protein expression under hypoxia. β3-AR silencing under hypoxia revealed an evident reduction of HIF-1α protein expression that confirmed the β3-AR modulation of HIF-1α expression. SR59230A treatment strongly reduced the HIF-1α target genes as GLUT1, HK-2 and HIF-1α expression at long time treatment confirming the β3-AR modulation of HIF-1α transcriptional activity. Conversely, the HIF-1α-transcriptional inhibitor Topotecan did not affect β3-AR expression confirming that is β3-AR that mediates HIF-1α activation. Immunofluorescence analysis showed that β3-AR co-localized with the nucleus under hypoxia more than normoxia. These results were confirmed by nuclear-cytoplasmic fragmentation that showed the presence of both β3-AR and HIF-1α proteins in the nucleus under hypoxia. Co-immunoprecipitation of β3-AR/HIF-1α revealed that under hypoxia, HIF-1α dissociates from β3-AR binding, but this process was abrogated by SR59230A. HIF-1α, released under hypoxia from the link with β3-AR, can play its transcriptional activity in the nucleus, while the binding with β3-AR blocks its transcriptional activity. Moreover, β3-AR regulation on HIF-1α was exerted through PHD2 activity at short time as SR59230A treatment under hypoxia increased the PHD2 protein expression but not at long time treatment, thus showing a different regulation of HIF-1α at different time points. In conclusion, the β3-AR upstream of the signaling β3-AR/HIF-1α axis exerts its role by PHD2 activity. Citation Format: Amada Pasha, Claudia Masi, Francesco Carrozzo, Martina Rosati, Alessia Boaretto, Alessandro Pini, Claudio Favre, Maura Calvani. Hypoxic HIF-1α stabilization dependent on β3-adrenoceptor localization in Ewing sarcoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4808.

Sympathetic β2-adrenergic receptor blockade overcomes docetaxel resistance in prostate cancer

PurposeDue to the limited effective therapies, resistance to docetaxel is ordinarily fatal and remains a critical clinical challenge.β2-adrenergic receptor(β2-AR)can promote the metastasis and invasion of prostate cancer, but the role in chemotherapy-resistant prostate cancer remains unclear. MethodsBy downloading the GEO database in NCBI, the expression of β2-AR in different prostate tissues was analyzed. We constructed docetaxel-resistant prostate cancer cell lines by the method of dose-escalation. LC3B-labeled stable cells and shAtg5 knockdown stable cells were constructed by lentivirus infection. The molecular mechanism of β2-AR affecting docetaxel sensitivity through apoptosis and autophage were investigated by flow cytometry, mitochondrial membrane potential and western blot. Then we detected the interaction between autophagy and apoptotic by performing immunoprecipitation assay. ResultsWe show that restraining the activity of β2-AR sensitized the cell response and reduced the resistance to docetaxel. The mechanism involves the regulation of β2-AR in the cellular response to docetaxel through apoptosis and autophagy via caspase signaling and Atg5/AMPK/mTOR pathway as well as the effect of β2-AR on the crosstalk between apoptosis and autophagy via p38 MAPK and JNK/c-Jun/FOXO3a signaling pathways. ConclusionOur data demonstrate that β2-AR inhibitor-induced autophagy and apoptosis contribute to the effectiveness responses to docetaxel in castration-resistant prostate cancer, and in combination with pharmacological agents of β2-AR and autophagy inhibitors may provide a potential therapeutic strategy to enhance the limited capacity of docetaxel to control castration-resistant prostate cancer.

Norepinephrine/β2-Adrenergic Receptor Pathway Promotes the Cell Proliferation and Nerve Growth Factor Production in Triple-Negative Breast Cancer.

Invasive ductal carcinoma (IDC) accounts for 90% of triple-negative breast cancer (TNBC). IDC is mainly derived from the breast ductal epithelium which is innervated by the 4th to 6th thoracic sympathetic nerves. However, little is known about the contribution of the interactions between sympathetic nerves and breast cancer cells to the malignant progression of TNBC. The expression levels of the β2-adrenergic receptor (β2-AR, encoded by ADRB2 gene), nerve growth factor (NGF), and tropomyosin receptor kinase A (TrkA) were determined using immunohistochemistry (IHC). NGF expression levels in the serum were compared by enzyme-linked immunosorbent assay (ELISA). Cell proliferation was assessed using the Cell Counting Kit-8 assay. The β2-AR, NGF, p-ERK, and p-CERB expression levels were determined using western blotting. TNBC cells and neuronal cells of the dorsal root ganglion (DRG) in 2-day-old Sprague Dawley rats were co-cultured. Using norepinephrine (NE), NGF, and β2-AR, NGF/TrkA blocker pretreatments, the axon growth of each group of DRG neuron cells was detected by immunofluorescence analysis. The sympathetic adrenergic neurotransmitter NE activated the ERK signaling pathway in TNBC cells. NE/β2-AR signaling promotes NGF secretion. NGF further facilitates the malignant progression of TNBC by increasing sympathetic neurogenesis. In the co-culture assay, the sympathetic adrenergic NE/β2-AR signal pathway also enhanced NGF secretion. NGF binds TrkA in DRG neurons and promotes axonal growth. These results suggest that NE/β2-AR pathway promotes cell proliferation and NGF production in triple-negative breast cancer.

Abstract 9608: Upregulation of Cardiac Beta3-Adrenergic Receptor-Activated iNOS Uncoupling Promotes Diabetic Cardiomyopathy in Type II Diabetic Mice: Role of Oxidant Stress

Background: Recent evidence highlights oxidative stress as an important mechanism to cardiac dysfunction in type 2 diabetes (T2D) and altered β 3 -adrenergic receptor (AR)-activated nitric oxide synthase (NOS) pathway contributing to this process. However, the NOS isoforms involved are controversial. The mechanism of how β 3 -AR stimulation impacts ROS, SERCA2a, and cardiac function in T2D is unclear. We tested the hypothesis that oxidant stress from upregulation of LV β 3 -AR-activated iNOS uncoupling promotes T2D cardiomyopathy. Methods: We compared myocyte β 1 - and β 3 -AR, NOS, peroxynitrite (NT), NADPH and SERCA2a expressions and myocyte functional responses to β- and β 3 -AR stimulation with isoproterenol (ISO,10 -8 M) and BRL-37344 (BRL,10 -8 M), respectively, in the absence and presence of iNOS inhibitor, 1400W (10 -5 M) of female mice over 14 weeks (W): 7 normal and 7 with T2D induced by 14 W high-fat diet (HFD) intake, but after HFD for 4 W receiving streptozotocin (STZ, 40 mg/kg/day, i.p. 5 days). Results: Versus normal myocytes, T2D myocytes had significantly increased protein levels of β 3 -AR (0.25 vs 0.14) and iNOS (0.25 vs 0.15) accompanied with increased oxidative stress indicated by significantly-elevated NT formation, NADPH (P67 -phox , 33% and p22 -phox , 29%) and decreased GTPCH expression (0.43 vs 0.85) and activity. T2D myocytes had significantly decreased β 1 -AR (0.35 vs 0.49) and SERCA2a (0.19 vs 0.29). These changes were associated with reduced cell contraction (dL/dt max , 75.4 vs 133.7 μm/s), relaxation (dR/dt max , 59.6 vs 113.8 μ m/s), and [Ca 2+ ] iT (0.16 vs 0.21) accompanied by diminished β-AR-stimulated positive inotropic response, but enhanced β 3 -AR-induced negative inotropic response. Only in T2D myocytes, pretreatment with 1400W improved basal cell function and augmented ISO-increased dL/dt max (64.5%) and [Ca 2+ ] iT (29.2%), but significantly limited BRL-induced decrease in dL/dt max (12.7%) and [Ca 2+ ] iT (9.8%). Conclusions: T2D is associated with contrasting changes on myocyte β 1 - and β 3 -AR expression with decreased SERCA2a and increased iNOS. Upregulation of β 3 -AR triggers iNOS uncoupling, leading to oxidative stress, thus promoting intrinsic myocyte dysfunction with impaired [Ca 2+ ] i regulation and reduced β-AR reserve.

Aerobic Exercise Prevents Arterial Stiffness and Attenuates Hyperexcitation of Sympathetic Nerves in Perivascular Adipose Tissue of Mice after Transverse Aortic Constriction.

We aimed to investigate the efficacy of exercise on preventing arterial stiffness and the potential role of sympathetic nerves within perivascular adipose tissue (PVAT) in pressure-overload-induced heart failure (HF) mice. Eight-week-old male mice were subjected to sham operation (SHAM), transverse aortic constriction-sedentary (TAC-SE), and transverse aortic constriction-exercise (TAC-EX) groups. Six weeks of aerobic exercise training was performed using a treadmill. Arterial stiffness was determined by measuring the elastic modulus. The elastic and collagen fibers of the aorta and sympathetic nerve distribution in PVAT were observed. Circulating noradrenaline (NE), expressions of β3-adrenergic receptor (β3-AR), and adiponectin in PVAT were quantified. During the recovery of cardiac function by aerobic exercise, thoracic aortic collagen elastic modulus (CEM) and collagen fibers were significantly decreased (p < 0.05, TAC-SE vs. TAC-EX), and elastin elastic modulus (EEM) was significantly increased (p < 0.05, TAC-SE vs. TAC-EX). Circulating NE and sympathetic nerve distribution in PVAT were significantly decreased (p < 0.05, TAC-SE vs. TAC-EX). The expression of β3-AR was significantly reduced (p < 0.05, TAC-SE vs. TAC-EX), and adiponectin was significantly increased (p < 0.05, TAC-SE vs. TAC-EX) in PVAT. Regular aerobic exercise can effectively prevent arterial stiffness and extracellular matrix (ECM) remodeling in the developmental course of HF, during which sympathetic innervation and adiponectin within PVAT might be strongly implicated.

EP16.03-013 Psychological Distress and Beta-2 Adrenergic Receptor Expression in Non-small Cell Lung Cancer Cells

Beta-2 Adrenergic Receptor (β2-AR) expression in cancer cells has been associated with tumour cell proliferation, both in animal models and clinical studies suggesting a role for β2-AR signalling in lung cancer progression. The association of patients’ psychological distress and β2-AR expression on lung cancer cells is unknown. The aim of the study is to explore the association of patient´s psychological distress to β2-ARs expression in patients operated for newly diagnosed non-small cell lung cancer (NSCLC).

The Effect of Swimming Training with Cinnamon Consumption on β3-AR and ERK2 Gene Expression in the Visceral Adipose Tissue of Diabetic Rats

Background: β3-AR is an important factor involved in the activation of ERK protein signaling cascade, which can positively contribute to the regulation of adipose tissue metabolism and its conversion into brown adipose tissue. Diabetes mellitus can lead to dysfunction of these factors. Objectives: The current study aimed to investigate the effect of swimming training combined with cinnamon consumption on β3-AR and ERK2 gene expression in the visceral adipose tissue from diabetic rats. Methods: In this experimental-fundamental study, 35 male Wistar rats (mean weight: 200 ± 20 g) were selected and randomly assigned into four groups after the induction of diabetes by streptozotocin. These groups included: (1) healthy control, (2) control, (3) swimming, (4) cinnamon, and (5) swimming cinnamon (n = 7 in each group). The training groups were put through a five-days-a-week workout for four weeks according to the training protocol. Gene expression levels were measured by in vitro real-time PCR. The collected data were analyzed using one-way ANOVA and Tukey’s post hoc test. Results: The expression levels of β3-AR and ERK2 protein genes in the visceral adipose tissue of diabetic rats (P = 0.0001) were significantly affected by swimming training and cinnamon consumption. Conclusions: It was shown that cinnamon supplementation may have increased β3-AR levels, which was more effective than training, while training had a greater effect on ERK2 levels and increased them. Therefore, it was concluded that cinnamon consumption combined with training may have greatly contributed to the conversion of white adipose into brown adipose tissues.

β-Adrenoceptor Blockade Moderates Neuroinflammation in Male and Female EAE Rats and Abrogates Sexual Dimorphisms in the Major Neuroinflammatory Pathways by Being More Efficient in Males.

Our previous studies showed more severe experimental autoimmune encephalomyelitis (EAE) in male compared with female adult rats, and moderating effect of propranolol-induced β-adrenoceptor blockade on EAE in females, the effect associated with transcriptional stimulation of Nrf2/HO-1 axis in spinal cord microglia. This study examined putative sexual dimorphism in propranolol action on EAE severity. Propranolol treatment beginning from the onset of clinical EAE mitigated EAE severity in rats of both sexes, but to a greater extent in males exhibiting higher noradrenaline levels and myeloid cell β2-adrenoceptor expression in spinal cord. This correlated with more prominent stimulatory effects of propranolol not only on CX3CL1/CX3CR1/Nrf2/HO-1 cascade, but also on Stat3/Socs3 signaling axis in spinal cord microglia/myeloid cells (mirrored in the decreased Stat3 and the increased Socs3 expression) from male rats compared with their female counterparts. Propranolol diminished the frequency of activated cells among microglia, increased their phagocyting/endocyting capacity, and shifted cytokine secretory profile of microglia/blood-borne myeloid cells towards an anti-inflammatory/neuroprotective phenotype. Additionally, it downregulated the expression of chemokines (CCL2, CCL19/21) driving T-cell/monocyte trafficking into spinal cord. Consequently, in propranolol-treated rats fewer activated CD4+ T cells and IL-17+ T cells, including CD4+IL17+ cells coexpressing IFN-γ/GM-CSF, were recovered from spinal cord of propranolol-treated rats compared with sex-matched saline-injected controls. All the effects of propranolol were more prominent in males. The study as a whole disclosed that sexual dimorphism in multiple molecular mechanisms implicated in EAE development may be responsible for greater severity of EAE in male rats and sexually dimorphic action of substances affecting them. Propranolol moderated EAE severity more effectively in male rats, exhibiting greater spinal cord noradrenaline (NA) levels and myeloid cell β2-adrenoceptor (β2-AR) expression than females. Propranolol affected CX3CR1/Nrf2/HO-1 and Stat3/Socs3 signaling axes in myeloid cells, favored their anti-inflammatory/neuroprotective phenotype and, consequently, reduced Th cell reactivation and differentiation into highly pathogenic IL-17/IFN-γ/GM-CSF-producing cells.

Loss of adipose TET proteins enhances β-adrenergic responses and protects against obesity by epigenetic regulation of β3-AR expression

β-adrenergic receptor (β-AR) signaling plays predominant roles in modulating energy expenditure by triggering lipolysis and thermogenesis in adipose tissue, thereby conferring obesity resistance. Obesity is associated with diminished β3-adrenergic receptor (β3-AR) expression and decreased β-adrenergic responses, but the molecular mechanism coupling nutrient overload to catecholamine resistance remains poorly defined. Ten-eleven translocation (TET) proteins are dioxygenases that alter the methylation status of DNA by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine and further oxidized derivatives. Here, we show that TET proteins are pivotal epigenetic suppressors of β3-AR expression in adipocytes, thereby attenuating the responsiveness to β-adrenergic stimulation. Deletion of all three Tet genes in adipocytes led to increased β3-AR expression and thereby enhanced the downstream β-adrenergic responses, including lipolysis, thermogenic gene induction, oxidative metabolism, and fat browning invitro and invivo. In mouse adipose tissues, Tet expression was elevated after mice ate a high-fat diet. Mice with adipose-specific ablation of all TET proteins maintained higher levels of β3-AR in both white and brown adipose tissues and remained sensitive to β-AR stimuli under high-fat diet challenge, leading to augmented energy expenditure and decreased fat accumulation. Consequently, they exhibited improved cold tolerance and were substantially protected from diet-induced obesity, inflammation, and metabolic complications, including insulin resistance and hyperlipidemia. Mechanistically, TET proteins directly repressed β3-AR transcription, mainly in an enzymatic activity-independent manner, and involved the recruitment of histone deacetylases to increase deacetylation of its promoter. Thus, the TET-histone deacetylase-β3-AR axis could be targeted to treat obesity and related metabolic diseases.

β2-adrenergic receptor drives the metastasis and invasion of pancreatic ductal adenocarcinoma through activating Cdc42 signaling pathway

Recent investigations indicate that β2-adrenergic receptor (β2-AR) signaling may facilitate the progression of various tumors, whose underlying mechanisms remain largely elusive. In the present study, we showed that β2-AR recruited Cdc42 in response to isoproterenol (ISO, a β-AR selective agonist) exposure in pancreatic ductal adenocarcinoma (PDAC) cells. The association of β2-AR and Cdc42 promoted the activation of Cdc42, as revealed by increased levels of Cdc42-GTP, and co-incubation with β2-AR antagonist abrogated ISO-induced activation of Cdc42. β2-AR-mediated Cdc42 activation further led to the phosphorylation of downstream PAK1, LIMK1 and Merlin. Furthermore, we showed that the activation of β2-AR/Cdc42 signaling facilitated the migration and invasion of PDAC cells. In addition, β2-AR and Cdc42 were overexpressed in PDAC specimens, compared with adjacent non-tumor tissues. High expression of β2-AR and Cdc42 were correlated with lymph node metastasis and TNM stage in PDAC patients. Finally, we showed that overexpression of β2-AR and Cdc42 were indicative of unfavorable prognosis in PDAC patients. Taken together, our findings suggested that β2-AR might facilitate Cdc42 signaling to drive the migration and invasion of PDAC cells, consequently resulting in the metastasis and dismal prognosis of PDAC. These studies highlight targeting β2-AR/Cdc42 signaling as a therapeutic strategy against PDAC.

β2-adrenergic receptor promotes liver regeneration partially through crosstalk with c-met

The β2-adrenergic receptor (β2AR) is a G protein-coupled receptor (GPCR) that mediates the majority of cellular responses to external stimuli. Aberrant expression of β2AR results in various pathophysiological disorders, including tumorigenesis, but little is known about its role in liver regeneration. This study aims to investigate the impact and the underlying mechanism of β2AR in liver regeneration. Here, we found that β2AR was upregulated during liver regeneration induced by 70% PH. Deletion of β2AR in mice resulted in 62% mortality 2 days post-PH, decreased proliferative marker expression and impaired liver function throughout regeneration. Moreover, AAV8-mediated overexpression of β2AR in hepatocytes accelerated the regeneration process and increased target gene expression. Mechanistically, β2AR recruited G-protein-coupled receptor kinase 2 (GRK2) to the membrane and then formed a complex with c-met to transactivate c-met signaling, which triggered downstream extracellular regulated protein kinase (ERK) signaling activation and nuclear translocation. Inhibition of c-met with SU11274 or ERK with U0126 decreased β2AR overexpression-induced hepatocyte proliferation. Our findings revealed that β2AR might act as a critical mediator regulating liver regeneration by crosstalk with c-met and activation of ERK signaling.

Expression and Role of β3-Adrenergic Receptor during the Differentiation of 3T3-L1 Preadipocytes into Adipocytes.

Simple SummaryThe β3-adrenergic receptor (β3-AR) has long been viewed as a potential therapeutic target for dealing with obesity. Although the lipolytic and thermogenic role of β3-AR in brown/beige adipocytes is well defined, the β3-AR’s adipogenic role in white adipocytes remains unclear at present. In this study, we investigated the expression and function of β3-AR in 3T3-L1 murine white preadipocytes. Knockdown of β3-AR led to less lipid accumulation and triglyceride (TG) content as well as less expression and phosphorylation levels of CCAAT/enhancer-binding protein-α (C/EBP-α) and peroxisome proliferator-activated receptor-γ (PPAR-γ) during 3T3-L1 preadipocyte differentiation. These findings reveal that the β3-AR inhibitor or antagonist could be a promising candidate for potential preventive and therapeutics against obesity.β3-adrenergic receptor (β3-AR) is expressed predominantly in mature white and brown/beige adipocytes. Although the lipolytic and thermogenic role of β3-AR in brown/beige adipocytes is well defined, the adipogenic role of β3-AR in white adipocytes remains unclear at present. In this study, we investigated the expression and function of β3-AR in differentiating 3T3-L1 cells, murine white preadipocytes. Of note, the expression of β3-AR at the protein and mRNA levels was highly induced in a time-dependent manner during 3T3-L1 preadipocyte differentiation. Interestingly, the results of the pharmacological inhibition study demonstrated the roles of p38 MAPK and PKC in the induction of β3-AR expression in differentiating 3T3-L1 cells. Knockdown of β3-AR led to less lipid accumulation and triglyceride (TG) content during 3T3-L1 preadipocyte differentiation with no cytotoxicity. Furthermore, knockdown of β3-AR resulted in a decrease in not only expression levels of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FASN), perilipin A, and leptin but also phosphorylation levels of signal transducer and activator of transcription-5 (STAT-5) during 3T3-L1 preadipocyte differentiation. In summary, these results demonstrate firstly that β3-AR expression is highly up-regulated in p38 MAPK and PKC-dependent manners, and the up-regulated β3-AR plays a crucial role in lipid accumulation in differentiating 3T3-L1 cells, which is mediated through control of expression and phosphorylation levels of C/EBP-α, PPAR-γ, STAT-5, FASN, and perilipin A.

Comparison of visceral fat lipolysis adaptation to high-intensity interval training in obesity-prone and obesity-resistant rats

Background/objectivesVisceral obesity is one of the key features of metabolic syndrome. High-intensity interval training (HIIT) could effectively reduce visceral fat, but its effects show strong heterogeneity in populations with different degrees of obesity. The mechanism may be related to the differential adaptation to training between obesity phenotypes, namely obesity prone (OP) and obesity resistant (OR). The aim of the present study was to compare adaptive changes of visceral adipose lipolysis adaptation to HIIT between OP and OR animals and further explore the upstream pathway.MethodsOP and OR Sprague Dawley rats were established after feeding a high-fat diet for 6 weeks; they were then divided into HIIT (H-OP and H-OR) and control (C-OP and C-OR) groups. After 12 weeks of HIIT or a sedentary lifestyle, animals were fasted for 12 h and then sacrificed for histology as well as gene and protein analysis. Visceral adipocytes were isolated without fasting for catecholamine stimulation and β3-adrenergic receptor (β3-AR) blockade in vitro to evaluate the role of upstream pathways.ResultsAfter training, there were no differences in weight loss or food intake between OP and OR rats (P > 0.05). However, the visceral fat mass, adipocyte volume, serum triglycerides and liver lipids of OP rats decreased by more than those of OR rats (P < 0.05). Meanwhile, the cell lipolytic capacity and the increase in the expression of β3-AR were higher in the OP compared with OR groups (P < 0.05). Although training did not increase sympathetic nervous system activity (P > 0.05), the cell sensitivity to catecholamine increased significantly in the OP compared with OR groups (P < 0.05). Following blocking β3-AR, the increased sensitivity disappeared.ConclusionWith HIIT, OP rats lost more visceral fat than OR rats, which was related to stronger adaptive changes in lipolysis. Increased β3-AR expression mediated this adaptation.

HIF-1-Dependent Induction of β3 Adrenoceptor: Evidence from the Mouse Retina.

A major player in the homeostatic response to hypoxia is the hypoxia-inducible factor (HIF)-1 that transactivates a number of genes involved in neovessel proliferation in response to low oxygen tension. In the retina, hypoxia overstimulates β-adrenoceptors (β-ARs) which play a key role in the formation of pathogenic blood vessels. Among β-ARs, β3-AR expression is increased in proliferating vessels in concomitance with increased levels of HIF-1α and vascular endothelial growth factor (VEGF). Whether, similarly to VEGF, hypoxia-induced β3-AR upregulation is driven by HIF-1 is still unknown. We used the mouse model of oxygen-induced retinopathy (OIR), an acknowledged model of retinal angiogenesis, to verify the hypothesis of β3-AR transcriptional regulation by HIF-1. Investigation of β3-AR regulation over OIR progression revealed that the expression profile of β3-AR depends on oxygen tension, similar to VEGF. The additional evidence that HIF-1α stabilization decouples β3-AR expression from oxygen levels further indicates that HIF-1 regulates the expression of the β3-AR gene in the retina. Bioinformatics predicted the presence of six HIF-1 binding sites (HBS #1-6) upstream and inside the mouse β3-AR gene. Among these, HBS #1 has been identified as the most suitable HBS for HIF-1 binding. Chromatin immunoprecipitation-qPCR demonstrated an effective binding of HIF-1 to HBS #1 indicating the existence of a physical interaction between HIF-1 and the β3-AR gene. The additional finding that β3-AR gene expression is concomitantly activated indicates the possibility that HIF-1 transactivates the β3-AR gene. Our results are indicative of β3-AR involvement in HIF-1-mediated response to hypoxia.

101 Adrenergic Receptor Expression Is Increased in Carotid Smooth Muscle from Severely Burned Rats

IntroductionSevere burn disrupts cardiovascular function which can lead to critical shock. To counteract cardiovascular collapse, there is a systemic increase of catecholamines released in response to severe burn. Previous studies showed that β1- adrenergic receptor (AR)_ protein expression was significantly increased in the cardiac right ventricles (RV) following burn injury, which is correlated with compromised cardiac dysfunction. Vascular smooth muscle contraction served to modulate blood pressure and improve circulatory perfusion. We hypothesize that ARs expression in major arteries are modified to initiate vascular functional changes following severe burn. In the current study, we report temporal ARs expression in murine carotid artery smooth muscle following severe burn.MethodsThirty-four adult Sprague-Dawley male rats received a 40% total body surface area (TBSA) scald burn followed by fluid resuscitation using the Parkland formula. Control animals received a sham burn procedure. Animals were serially euthanized between 6 hours and 14 days after burn and endothelium-intact common carotid arteries were harvested for histological analysis.ResultsImmunohistochemical staining data demonstrated expression of adrenergic receptors (AR) (α1, α2, β1, and β2) were differentially changed in response to injury over time. α1a-AR expression significantly increased within the carotid artery tunica media 7-days after burn (p< 0.05). As a negative feedback of inhibitory of norepinephrine signaling, AR-α2a expression did not significantly change. AR-β1 expression also had no change over time after burn. Interestingly, functioning to relax vascular smooth muscle, a significant elevation of β2-AR expression within the carotid artery tunica media was observed only at 1-day after burn (p< 0.05).ConclusionsIn summary, immunohistochemistry showed that carotid arterial adrenergic receptor expressions of α1a-AR and β2-AR are significantly altered in response to severe burn, which may contribute to vascular contractility in burn rats.

Ezrin knockdown reduces procaterol-stimulated ciliary beating without morphological changes in mouse airway cilia.

Mucociliary clearance, which is conducted by beating cilia cooperating with the surface mucous layer, is a major host defense mechanism of the airway epithelium. Ezrin, a crosslinker between membrane proteins and the actin cytoskeleton, is located in microvilli and around the basal bodies in airway ciliary cells. It is also likely that ezrin plays an important role in apical localization of β2 adrenergic receptor (β2AR) in airway ciliary cells. Here, we studied the physiological roles of ezrin by using trachea and airway epithelial cells prepared from ezrin-knockdown (Vil2kd/kd) mice. The trachea and airway ciliary cells of Vil2kd/kd mice presented a normal morphology and basal body orientation, suggesting that ezrin is not directly involved in development and planar cell polarity of cilia. Procaterol stimulates ciliary beating (frequency and amplitude) via β2AR in the airway ciliary cells. In the Vil2kd/kd mice, airway ciliary beating stimulated with procaterol was partly inhibited due to the impairment of cell surface expression of β2AR. These results suggest that ezrin regulates the beating of airway ciliary cells by promoting the apical surface localization of β2AR. This article has an associated First Person interview with the first author of the paper.

RSV-induced changes in a 3-dimensional organoid model of human fetal lungs.

We have shown that respiratory syncytial virus (RSV) can spread hematogenously from infected airways of a pregnant woman to the developing fetal lungs in utero. This study sought to measure RSV replication, cytopathic effects, and protein expression in human lung organoids (HLOs) reproducing architecture and transcriptional profiles of human fetal lungs during the 1st trimester of gestation. HLOs derived from human pluripotent stem cells were microinjected after 50 or 100 days in culture with medium or recombinant RSV-A2 expressing the red fluorescent protein gene (rrRSV). Infection was monitored by fluorescent microscopy and PCR. Immunohistochemistry and proteomic analysis were performed. RSV infected HLOs in a dose- and time-dependent manner. RSV-infected HLOs increased expression of CC10 (Club cells), but had sparse FOXJ1 (ciliated cells). Disruption of F-actin cytoskeleton was consistent with proteomic data showing a significant increase in Rho GTPases proteins. RSV upregulated the transient receptor potential vanilloid 1 (TRPV1) channel and, while β2 adrenergic receptor (β2AR) expression was decreased overall, its phosphorylated form increased. Our data suggest that prenatal RSV infection produces profound changes in fetal lungs’ architecture and expression profiles and maybe an essential precursor of chronic airway dysfunction. expression profiles, and possibly be an important precursor of chronic airway dysfunction.

Discovery of dual-target ligands binding to beta2-adrenoceptor and cysteinyl-leukotriene receptor for the potential treatment of asthma from natural products derived DNA-encoded library

The design, synthesis, and discovery of dual-target compounds are considered as a promising strategy to develop new drugs with improved safety and efficacy compared with single-target drugs. This necessitates development of the methodologies that enable us to rapidly and accurately achieve the dual-target leads. Applying rosmarinic acid, 18β-glycyrrhetinic acid, rhein, and ferulic acid as template building blocks, we introduced the self-assembling DNA encoded technique to build the library containing 1,000 compounds. These compounds were screened by receptor chromatography with immobilized beta2-adrenoceptor (β2-AR) and cysteinyl-leukotriene receptor (CysLT), whereby we obtained a derivative of 18β-glycyrrhetinic acid (XC267) that specifically binds to the two receptors. In vitro assessment demonstrated the desired binding affinity of 6.57 × 104 M−1 to β2-AR, 2.82 × 104 M−1 to CysLT, and the dissociation rate constant of 7.52 s−1 to β2-AR, 17.2 s−1 to CysLT. Pharmacological examination with ovalbumin-induced mice demonstrated that XC267 significantly reduced the levels of IL-4, IL-13, and IgE after oral administration of 10 mg/kg. By Western blot analysis, we observed an up-regulated expression of β2-AR and a blocked level of CysLT with a dose-dependent manner in pulmonary bronchial. Our results suggest XC627 is a potential candidate to treat asthma by simultaneously regulating the signaling pathway of the two receptors.

Abstract P4-04-01: β2-adrenergic receptor signaling regulates metabolic pathways critical for the function of myeloid-derived suppressor cells

Abstract Summary Nerve-driven chronic adrenergic stress can suppress anti-tumor immunity. However, details are still missing or poorly understood. Catecholamines (epinephrine, norepinephrine) released by sympathetic nerves can activate adrenergic receptors present on nearly every cell type including myeloid derived suppressor cells (MDSCs). MDSCs are increasingly recognized as critical players in tumor immunology because, in addition to their fundamental roles in suppressing effector NK cells, CD8+ T cells and CD4+ T cells, they also play a direct role in tumor growth, differentiation and metastasis. Recently, we have shown that β2 adrenergic receptor signaling activated by chronic stress increases the immunosuppressive function of MDSCs, but the precise mechanisms remain unresolved. Building upon our earlier work, we now have discovered that the beta-2 adrenergic receptor (β2-AR) stress pathway drives the immune suppressive activity of MDSCs through altering their metabolism. First, we found that the expression of surface β2-AR on MDSCs increases with tumor growth in 4T1 breast cancer model and patients with breast cancer. We also found that β2-AR signaling decreases glycolysis, while increasing oxidative phosphorylation and fatty acid oxidation (FAO). β2-AR signaling also increased mitochondrial intensity and mitochondrial potential of MDSCs both in vitro and in vivo. β2-AR signaling in MDSCs also increased the expression of Carnitine Palmitoyltransferase 1A (CPT1A) necessary for the FAO-mediated immunosuppressive function of MDSCs. Blocking CPT1A using etomoxir decreased tumor growth and immunosuppressive function of MDSCs in Wild Type (WT) mice but not β2-AR-/- mice or severe combined immunodeficient mice (SCID) mice. Moreover, we found that β2-AR signaling increases autophagy and activates the arachidonic acid cycle, both required for increasing the release of the immunosuppressive mediator, PGE2 in both mouse MDSCs and. PBMCs derived MDSCs. Together, our data reveal that stress-driven β2-AR signaling is an important physiological determinant that regulates key metabolic pathways in MDSCs enabling their immunosuppressive function. These data reveal a major, physiologically relevant role for nervous activity and adrenergic stress in MDSC-tumor biology. Keywords: β2 adrenergic receptor, stress, MDSC, Metabolism, Breast Cancer, Citation Format: Hemn Mohammadpour. β2-adrenergic receptor signaling regulates metabolic pathways critical for the function of myeloid-derived suppressor cells [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-04-01.