Adrenergic Receptor Signaling Research Articles

Insulin acts as an atypical KCNQ1/KCNE1‐current activator and reverses long QT in insulin‐resistant aged rats by accelerating the ventricular action potential repolarization through affecting the β3‐adrenergic receptor signaling pathway

Insufficient-heart function is associated with myocardial insulin resistance in the elderly, particularlyassociated with long-QT, in a dependency on dysfunctional KCNQ1/KCNE1-channels. So, we aimed to examine the contribution of alterations in KCNQ1/KCNE1-current (IKs ) to the aging-related remodeling of the heart as well as the role of insulin treatment on IKs in the aged rats. Prolonged late-phase action potential (AP) repolarization of ventricular cardiomyocytes from insulin-resistant 24-month-old rats was significantly reversed by in vitro treatment of insulin or PKG inhibitor (in vivo, as well) via recovery in depressed IKs . Although the protein level of either KCNQ1 or KCNE1 in cardiomyocytes was not affected with aging, PKG level was significantly increased in those cells. The inhibited IKs in β3 -ARs-stimulated cells could be reversed with a PKG inhibitor, indicating the correlation between PKG-activation and β3 -ARs activation. Furthermore, in vivo treatment of aged rats, characterized by β3 -ARs activation, with either insulin or a PKG inhibitor for 2 weeks provided significant recoveries in IKs , prolonged late phases of APs, prolonged QT-intervals, and low heart rates without no effect on insulin resistance. In vivo insulin treatment provided also significant recovery in increased PKG and decreased PIP2 level, without the insulin effect on the KCNQ1 level in β3 -ARs overexpressed cells. The inhibition of IKs in aged-rat cardiomyocytes seems to be associated with activated β3 -ARs dependent remodeling in the interaction between KCNQ1 and KCNE1. Significant recoveries in ventricular-repolarization of insulin-treated aged cardiomyocytes via recovery in IKs strongly emphasize two important issues: (1) IKs can be a novel target in aging-associated remodeling in the heart and insulin may be a cardioprotective agent in the maintenance of normal heart function during the aging process. (2) This study is one of the first to demonstrate insulin'sbenefits on long-QT in insulin-resistant aged rats by accelerating the ventricular AP repolarization through reversing the depressed IKs via affecting the β3 -ARs signaling pathway and particularly affecting activated PKG.

Clinical and Immune Responses of Peripheral Chemical Sympathectomy in Enterovirus 71 Infection.

The activation of the sympathetic nervous system, release of norepinephrine (NE), and adrenergic receptor signaling participate in and regulate the complicated enterovirus 71 (EV71) brainstem encephalitis (BE). The neurotoxin 6-hydroxydopamine (6-OHDA) selectively ablates sympathetic nerves and markedly depletes NE in innervated organs. Changes in the plasma levels of NE, severity score, cytokine profiles, and percentages of immunophenotype expression in 7-day-old Bltw : CD1 (ICR) mice infected with EV71, with or without 6-OHDA treatment, were compared. The survival rate (76.9%) of EV71-infected and 6-OHDA (30 μg/g)-treated mice was increased significantly. The clinical scores were decreased markedly on days 8-12 in MP4-infected and 6-OHDA-treated mice compared to those without treatment. The results showed that the plasma levels of NE, epinephrine, and dopamine were decreased on days 4–8 after 6-OHDA treatment and at most on day 8. The plasma levels of interleukin (IL)-12p70, tumor necrosis factor, IL-6, and IL-10 did not change significantly after 6-OHDA treatment. Interferon-γ levels decreased evidently on days 4, 6, and 8 after 6-OHDA treatment. The absolute events of CD3+CD4+, CD3+CD8+, and CD3+NK1.1+ cells of peripheral blood mononuclear cells were increased significantly in MP4-infected and 6-OHDA-treated mice compared to those without treatment. In splenocytes, the absolute cells of CD3−NK1.1+, CD3+NK1.1+ and CD11b+Gr-1+ cells of EV71-infected mice were increased significantly after 6-OHDA treatment. These findings suggested that 6-OHDA may be used a probe to explore clinical improvements and immune responses in the complicated EV71 infection. Taken together, peripheral chemical sympathectomy contribute to further understand the immunopathogenesis of EV71 BE with autonomic nervous system dysregulation.

Regulation of hyaluronan production by β2 adrenergic receptor signaling

BackgroundHyaluronan (HA), the main component of the extracellular matrix, is involved in tissue elasticity and cell scaffolding, and in progression of conditions such as cancer, inflammation and wound healing. Signaling by G protein coupled receptor (GPCR) activation increases expression of hyaluronan synthase (HAS) and HA production. The β2 adrenergic receptor (β2AR) is a catecholamine-liganded GPCR that is involved in cancer progression and wound healing. Since HA and β2AR are involved in a common pathology, we investigated whether β2AR signaling regulates HA production. MethodsAfter stimulating β2AR-expressing cells with a β agonist, the amount of HA in the culture medium was measured and HAS expression was examined by real-time PCR. A variety of signaling molecule inhibitors were used to identify signaling pathways that alter HAS expression. Resultsβ2AR activation increased HA production and enhanced HAS2 expression. The increase in HAS2 expression by β2AR activation occurred via the Gs - adenylyl cyclase - PKA - CREB signal transduction pathway. ConclusionsDownstream signal transduction by β2AR activation increased HA production by enhancing transcription of the HAS2 gene. This study suggests that β2AR is a GPCR that regulates HA production, and that stimulation with a catecholamine (β2 agonist) can regulate HA production. General significanceβ2AR may function through regulation of HA production in cancer progression and wound healing.

Obesity modifies the implantation window and disrupts intrauterine embryo positioning in rats.

Obesity is a chronic disease that impairs female reproduction. When gestation is achieved, maternal obesity can cause offspring's health complications. We intended to evaluate the effects of maternal pre-conceptional obesity on uterine contractile activity, embryo implantation and offspring development. Using cafeteria diet-induced obesity as an animal model, we found that maternal obesity delays embryo transport from the oviduct to the uterus and alters the intrauterine embryo positioning. Adrenergic receptor (AR) signaling is involved in embryo positioning, so all AR isoforms were screened in the pre-implantation uteri. We found that the β2AR is the dominant isoform in the rat uteri and that obesity causes its upregulation. Although β2AR activation is known to induce uterine relaxation, higher spontaneous contractile activity was detected in obese dams. Uteri from obese dams showed a higher sensitivity to salbutamol (a selective agonist of β2AR) than controls, consistent with the higher β2AR levels detected in those animals. Despite this, in obese dams, some embryos were still in the oviduct at the predicted time of initial embryo attachment, embryo implantation is successfully carried out since the total number of fetuses on gd 18.5 were similar between control and obese dams. These findings show that obesity is modifying the implantation window. Moreover, we found that maternal obesity resulted in macrosomia in the offspring, which is an important predictor of fetal programming of postnatal health. Hence, our results show that maternal obesity prior to pregnancy not only disturbs the implantation process, but also affects offspring development.

Impact of Aldosterone on the Failing Myocardium: Insights from Mitochondria and Adrenergic Receptors Signaling and Function.

The mineralocorticoid aldosterone regulates electrolyte and blood volume homeostasis, but it also adversely modulates the structure and function of the chronically failing heart, through its elevated production in chronic human post-myocardial infarction (MI) heart failure (HF). By activating the mineralocorticoid receptor (MR), a ligand-regulated transcription factor, aldosterone promotes inflammation and fibrosis of the heart, while increasing oxidative stress, ultimately induding mitochondrial dysfunction in the failing myocardium. To reduce morbidity and mortality in advanced stage HF, MR antagonist drugs, such as spironolactone and eplerenone, are used. In addition to the MR, aldosterone can bind and stimulate other receptors, such as the plasma membrane-residing G protein-coupled estrogen receptor (GPER), further complicating it signaling properties in the myocardium. Given the salient role that adrenergic receptor (ARs)—particularly βARs—play in cardiac physiology and pathology, unsurprisingly, that part of the impact of aldosterone on the failing heart is mediated by its effects on the signaling and function of these receptors. Aldosterone can significantly precipitate the well-documented derangement of cardiac AR signaling and impairment of AR function, critically underlying chronic human HF. One of the main consequences of HF in mammalian models at the cellular level is the presence of mitochondrial dysfunction. As such, preventing mitochondrial dysfunction could be a valid pharmacological target in this condition. This review summarizes the current experimental evidence for this aldosterone/AR crosstalk in both the healthy and failing heart, and the impact of mitochondrial dysfunction in HF. Recent findings from signaling studies focusing on MR and AR crosstalk via non-conventional signaling of molecules that normally terminate the signaling of ARs in the heart, i.e., the G protein-coupled receptor-kinases (GRKs), are also highlighted.

MO330ACTIVATION OF Β2 ADRENERGIC RECEPTOR SIGNALING IN MACROPHAGES BLOCKS SYSTEMIC INFLAMMATION AND PROTECTS AGAINST RENAL ISCHEMIA/REPERFUSION INJURY

Abstract Background and Aims The sympathetic nervous system regulates immune cell dynamics. However, the detailed role of sympathetic signaling in inflammatory diseases is still unclear because it varies according to the disease situation and responsible cell types. Here, we focused on sympathetic signaling in macrophages and sought to determine its detailed roles in lipopolysaccharide (LPS)-induced systemic inflammation and renal ischemia/reperfusion injury (IRI). Method In vitro, RAW 264.7 cells and murine peritoneal macrophages were used to determine the effects of β2 adrenergic receptor (Adrb2) signaling on LPS-induced proinflammatory cytokine (tumor necrosis factor-α; TNF-α) production. We also identified the critical gene that mediates the anti-inflammatory effect of Adrb2 signaling by RNA-sequencing. In vivo, we examined the effects of salbutamol (a selective Adrb2 agonist) in LPS-induced systemic inflammation and renal IRI. The involvement of macrophage Adrb2 signaling was confirmed by macrophage-specific Adrb2 conditional knockout (cKO) mice and adoptive transfer of salbutamol-treated macrophages. We also performed single-cell RNA sequencing of renal tissue to analyze the renoprotective role of salbutamol-treated macrophages in detail. Results In vitro, norepinephrine, a sympathetic neurotransmitter, suppressed LPS-induced TNF-α production in macrophages. This anti-inflammatory effect was also induced by salbutamol and reversed by butoxamine (a selective Adrb2 antagonist) in a dose-dependent manner, indicating the importance of Adrb2 in this process. RNA sequencing of these macrophages revealed that T-cell immunoglobulin and mucin-3 (Tim3) expressions were upregulated by the activation of Adrb2 signaling, which partially mediated the anti-inflammatory phenotypic alteration in macrophages. In vivo, salbutamol administration mitigated LPS-induced systemic inflammation and protected against renal IRI; this protection was mitigated in macrophage-specific Adrb2 cKO mice. Adoptive transfer of salbutamol-treated macrophages also protected against renal IRI (Figure 1). Single-cell RNA sequencing revealed that this protection was associated with the accumulation of Tim3-expressing macrophages in the renal tissue. Conclusion The activation of β2 adrenergic receptor signaling in macrophages induces anti-inflammatory phenotypic alterations partially via the induction of Tim3 expressions, which blocks LPS-induced systemic inflammation and protects against renal IRI.

POS-074 ACTIVATION OF SYMPATHETIC SIGNALING IN MACROPHAGES MITIGATES SYSTEMIC INFLAMMATION AND PROTECTS AGAINST RENAL ISCHEMIA/REPERFUSION INJURY

The sympathetic nervous system regulates immune cell dynamics. However, the detailed role of sympathetic signaling in inflammatory diseases is still unclear because it varies according to the disease situation and responsible cell types. Here, we focused on sympathetic signaling in macrophages and sought to determine its detailed roles in lipopolysaccharide (LPS)-induced systemic inflammation and renal ischemia/reperfusion injury (IRI). In vitro, we used RAW 264.7 cells and murine peritoneal macrophages to determine the effects of β2 adrenergic receptor (ADRB2) signaling on LPS-induced proinflammatory cytokine (TNF-α) production. We also identified the critical gene that mediates the anti-inflammatory effect of ADRB2 signaling by RNA-sequencing (RNA-seq). In vivo, we examined the effects of salbutamol (a selective ADRB2 agonist) in LPS-induced systemic inflammation and renal IRI. The involvement of macrophage ADRB2 signaling was confirmed by macrophage-specific ADRB2 conditional knockout (cKO) mice and adoptive transfer of salbutamol-treated macrophages. We also performed single-cell RNA-seq of renal tissue to analyze the renoprotective role of salbutamol-treated macrophages in detail. In vitro Norepinephrine, a main sympathetic neurotransmitter, suppressed LPS-induced TNF-α production in macrophages. This anti-inflammatory effect was also induced by salbutamol and reversed by butoxamine (a selective ADRB2 antagonist) in a dose-dependent manner, indicating the importance of ADRB2 in this process. RNA-seq of these macrophages revealed that T-cell immunoglobulin and mucin-3 (TIM-3) expressions were upregulated by the activation of ADRB2 signaling, which partially mediated the anti-inflammatory phenotypic alteration in macrophages.<In vivo>Salbutamol administration mitigated LPS-induced systemic inflammation and protected against renal IRI; this protection was mitigated in macrophage-specific ADRB2 cKO mice. Adoptive transfer of salbutamol-treated macrophages also protected against renal IRI. Single-cell RNA-seq revealed that this protection was associated with the accumulation of TIM-3-expressing macrophages in the renal tissue. The activation of sympathetic signaling in macrophages induces anti-inflammatory phenotypic alterations partially via the induction of TIM-3 expressions, which blocks LPS-induced systemic inflammation and protects against renal IRI.

130 Burn Injury Reduces Bone Marrow Mesenchymal Stem Cells and Sensitizes Their Adrenergic Receptor Subgroups in a Murine Model

Abstract Introduction Previous burn and traumatic injury studies have established that adrenergic signaling is increased after burn injury and may lead to an impairment of hematopoietic cell development in the bone marrow (BM). Nonetheless, mesenchymal stem cells (MSCs), which have gained momentum in regenerative medicine also play a predominant role in the BM niche. Understanding the propensity of the adrenergic receptor (AR) response by MSCs can be utilized for devising targeted therapies. However, the traditional plastic adherence procedure using ex vivo culture of BM cells for several weeks may skew the actual characteristics of MSCs. Our current study focused on isolating MSCs from freshly obtained BM in a murine scald burn model with a goal to characterize the expression pattern of native AR subgroups present on BM MSCs as compared to sham mice. Methods Eight, two-month-old adult female mice were subjected to a 15% total body 3rd degree burn or sham burn. The mice were sacrificed 7 days later. Femurs were removed and total bone marrow cells were flushed out. Multi parametric flow cytometry was used to gate for cells negative for hematopoietic cell markers (CD45, CD11B) and positive for MSC markers (CD105, CD106, SSEA, Ly6A) and AR subgroups (α1, α2, β1, β2, β3). We measured the number of BM MSCs, quantified the subtypes of ARs present on MSCs, and compared the ratio of AR antibody binding per total MSC population. Results Overall the frequency of MSCs per million total BM cells decreased by 48% post-burn injury with165,300 ± 194 in sham versus 110,000 ± 30 in burn displayed as bar graph in Panel A. Over 90% of MSCs consistently express β2 AR and only 10% express α2 AR subgroup in both scald and sham burn. Presence of other subgroups ranged from 50% to 80% of MSCs as seen in histograms to the right of dotted line in Panel B. Our AR propensity score based on AR mean fluorescence intensity adjusted to total number of MSCs present was increased by 2.8-fold for α1, 2.5-fold for β1, 1.6-fold for β3, and 1.3-fold for β2 AR subgroups (Panel C). These findings indicate burn injury not only decreases the frequency of BM MSCs but also increases the affinity of certain AR subgroups present on MSCs. Since BM MSCs are the major source of cytokines, chemokines and growth factors; detailed studies on AR mediated signaling in BM MSCs is warranted. Conclusions Polarization of AR signaling in BM MSCs by burn-induced catecholamines may have broader implications for comorbidities such as bone resorption and muscle wasting observed in human patients post burn trauma.

Berries and Their Polyphenols as a Potential Therapy for Coronary Microvascular Dysfunction: A Mini-Review.

Ischemia with no obstructive coronary artery disease (INOCA) is a common diagnosis with a higher prevalence in women compared to men. Despite the absence of obstructive coronary artery disease and no structural heart disease, INOCA is associated with major adverse cardiovascular outcomes as well a significant contributor to angina and related disability. A major feature of INOCA is coronary microvascular dysfunction (CMD), which can be detected by non-invasive imaging and invasive coronary physiology assessments in humans. CMD is associated with epicardial endothelial-dependent and -independent dysfunction, diffuse atherosclerosis, and left-ventricular hypertrophy, all of which lead to insufficient blood flow to the myocardium. Inflammatory and oxidative stress signaling, upregulation of the renin-angiotensin-aldosterone system and adrenergic receptor signaling are major drivers of CMD. Treatment of CMD centers around addressing cardiovascular risk factors; however, there are limited treatment options for those who do not respond to traditional anti-anginal therapies. In this review, we highlight the ability of berry-derived polyphenols to modulate those pathways. The evidence supports the need for future clinical trials to investigate the effectiveness of berries and their polyphenols in the treatment of CMD in INOCA patients.

Chronic Adrenergic Stress Contributes to Metabolic Dysfunction and an Exhausted Phenotype in T Cells in the Tumor Microenvironment.

Metabolic dysfunction and exhaustion in tumor-infiltrating T cells have been linked to ineffectual antitumor immunity and the failure of immune checkpoint inhibitor therapy. We report here that chronic stress plays a previously unrecognized role in regulating the state of T cells in the tumor microenvironment (TME). Using two mouse tumor models, we found that blocking chronic adrenergic stress signaling using the pan β-blocker propranolol or by using mice lacking the β2-adrenergic receptor (β2-AR) results in reduced tumor growth rates with significantly fewer tumor-infiltrating T cells that express markers of exhaustion, with a concomitant increase in progenitor exhausted T cells. We also report that blocking β-AR signaling in mice increases glycolysis and oxidative phosphorylation in tumor-infiltrating lymphocytes (TIL), which associated with increased expression of the costimulatory molecule CD28 and increased antitumor effector functions, including increased cytokine production. Using T cells from Nur77-GFP reporter mice to monitor T-cell activation, we observed that stress-induced β-AR signaling suppresses T-cell receptor (TCR) signaling. Together, these data suggest that chronic stress-induced adrenergic receptor signaling serves as a "checkpoint" of immune responses and contributes to immunosuppression in the TME by promoting T-cell metabolic dysfunction and exhaustion. These results also support the possibility that chronic stress, which unfortunately is increased in many patients with cancer following their diagnoses, could be exerting a major negative influence on the outcome of therapies that depend upon the status of TILs and support the use of strategies to reduce stress or β-AR signaling in combination with immunotherapy.

Abstract PS17-40: Fatty acid metabolism at the connection of histone methylation and mammary cell plasticity

Abstract INTRODUCTION:Metabolic switching has been linked with cancer progression. We initially reported increased expression of lipids metabolism genes in the contralateral breasts of women with unilateral estrogen receptor negative (ER-) breast cancer. We then demonstrated chromatin remodeling in normal mammary epithelial cells following exposure to lipids. Metabolites from intermediate metabolism are substrates that generate chromatin modifications, connecting metabolism to epigenetics. Key to this crosstalk is the fact that the kinetic and thermodynamic properties of chromatin modification reactions are in line with the dynamic range of the physiological concentrations of the corresponding intermediates in metabolism. Since substrates for histone methylation and acetylation reactions often have cellular concentrations that are commensurate with enzyme Km values, and are sensitive and responsive to changes in metabolism, we now present evidence regarding changes in metabolic flux and cellular plasticity connecting lipid metabolism to ER- cancer progression. Methods:MCF-10A cells were grown in the presence of medium chain fatty acid- octanoic acid (5mM) for 24 hours. RNA sequencing was performed on the treated and control cells using Illumina Next Seq 500 for 75bp single-read sequencing. Differential expression and gene set enrichment analyses were utilized to identify significantly enriched biological processes and molecular functions upon fatty acid treatment. Differential metabolic flux was determined using flux balance analysis. For proteomic analysis of post-translational histone modifications, histones were acid extracted from nuclei and LC-MS based mass spectrometry was used to quantitate the modifications and data is represented as the relative abundance in %. Results:Transcriptome data from RNA sequencing, incorporated into the human metabolic network reconstruction, revealed a significant increase in methylation flux in octanoate treated MCF10-A cells. The treated cells showed an increase in the flux in fatty acid oxidation and one-carbon metabolism reactions. The proteomic histone modification profile showed an increase in histone methylation specifically at H3K9, H3K4, H3K27 and H3K36, which corroborates with the GSEA analysis showing a significant correlation of H3K27 methylation (NES = 2.47, q-value = 0.05), a marker of constitutive heterochromatin, in the octanoate treated phenotype. Further, RNA-Seq of octanoate treated MCF-10A cells revealed prominent upregulation of cell-fate commitment and cell differentiation pathways, specifically neural differentiation, and adenylate cyclase-activating adrenergic receptor signaling. Conclusion:Lipids are a source of acetyl-CoA which serves as a donor for histone acetylation; our data shows that resultant increased flux through metabolic reactions produces s-adenosine methionine (SAM), an important methylating agent. These post-translational modifications have profound effects on chromatin structure, effecting changes that range from the expression of a single gene to a complete conversion of phenotype. We observe both an alteration of the molecular phenotype, as well as adenylate cyclase-activating adrenergic receptor signaling, which may be a clue to the development of ER- disease as GWAS have revealed that the adenylate cyclase-activating pathway is enriched in susceptibility to ER-negative disease. Citation Format: Shivangi Yadav, Ranya KA Virk, Carolina H Chung, Sriram Chandrasekaran, Vadim Backman, Seema Ahsan Khan, Susan Elizabeth Clare. Fatty acid metabolism at the connection of histone methylation and mammary cell plasticity [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-40.

Divergence of neuroimmune circuits activated by afferent and efferent vagal nerve stimulation in the regulation of inflammation.

It has previously been shown that afferent and efferent vagal nerve stimulation potently inhibits lipopolysaccharide (LPS)-induced inflammation Our data show inhibition of inflammation by efferent but not afferent vagal nerve stimulation requires T-cell derived acetylcholine We show that afferent and efferent neuroimmune circuits require β2 -adrenergic receptor signalling ABSTRACT: Chronic inflammation due to inappropriate immune cell activation can have significant effects on a variety of organ systems, reducing lifespan and quality of life. As such, highly targeted control of immune cell activation is a major therapeutic goal. Vagus nerve stimulation (VNS) has emerged as a therapeutic modality that exploits neuroimmune communication to reduce immune cell activation and consequently inflammation. Although vagal efferent fibres were originally identified as the primary driver of anti-inflammatory actions, the vagus nerve in most species of animals predominantly comprises afferent fibres. Stimulation of vagal afferent fibres can also reduce inflammation; it is, however, uncertain how these two neuroimmune circuits diverge. Here we show that afferent VNS induces a mechanism distinct from efferent VNS, ameliorating lipopolysaccharide (LPS)-induced inflammation independently of T-cell derived acetylcholine (ACh) which is required by efferent VNS. Using a β2 -adrenergic receptor antagonist (β2 -AR), we find that immune regulation induced by intact, afferent, or efferent VNS occurs in a β2- AR-dependent manner. Together, our findings indicate that intact VNS activates at least two distinct neuroimmune circuits each with unique mechanisms of action. Selective targeting of either the vagal efferent or afferent fibres may provide more personalized, robust and effective control over inappropriate immune responses.

Abstract 12717: Enhance Negative Modulation of Beta 3 -Adrenergic Stimulation on Cardiomyocyte Functional Performance, [Ca 2+ ] i Regulation and β-Adrenergic Reserve in Rats Expressing Human Angiotensinogen Gene

Background: Transgenic rats expressing the human angiotensinogen gene [TGR (hAogen) 1623] (hAogen) exhibit sustained hypertension and systolic dysfunction associated with altered cardiac renin-angiotensin system and β- adrenergic receptor (AR) signal transduction systems. We have shown previously, in contrast to β 1 - and β 2 -ARs, β 3 -ARs are linked to G i proteins, and stimulation of β 3 -ARs inhibits cardiac contraction and relaxation. Hypertension is associated with increased cardiac expression of G i proteins. This may alter β 3 -AR stimulation and play an important role in the cardiac functional impairment of this humanized model of hypertension. However, the alteration and functional effect of β 3 -AR activation in this model are unknown. We tested the hypothesis that high cardiac tissue Ang II content in hAogen may cause an up-regulation of cardiac β 3 -AR, which exacerbates myocyte dysfunction and impairs calcium regulation, thereby directly contributing to the cardiac dysfunction. Methods: We compared LV myocyte β 3 -AR expression and myocyte functional and [Ca 2+ ] i transient ([Ca 2+ ] iT ) responses to β- and β 3 -AR stimulation in myocytes obtained from 8 Sprague Dawley (SD) control and 8 hAogen male adult rats. Results: Versus SD, in hAGT rats, basal myocyte contraction (dL/dt max , 107.1 vs 138.8 μm/s), relaxation (dR/dt max , 94.0 vs 103.9 μm/s) and [Ca 2+ ] iT (0.15 vs 0.21) were depressed. A non-selective β-AR agonist, isoproterenol (ISO) (10 -8 M) produced significantly smaller increases in dL/dt max , (42% vs. 61%), dR / dtmax (35% vs. 51%), and [Ca 2+ ] iT (20% vs. 30%). Moreover, versus SD, in hAogen rats, LV myocyte β 3 -AR protein level increased by 32% (0.29 vs 0.22) with resulted significantly altered myocyte functional response to β 3 -AR stimulation. Compared with the changes in SD myocytes, in hAogen myocytes, BRL (10 -8 M) produced a significantly greater decreases in dL/dt max , (27% vs 12%), dR/dt max (28% vs 11%), and [Ca 2+ ] iT (17% vs 10%). Conclusions: TGR (hAogen) 1623, this humanized model of hypertension is associated with an up-regulation of LV myocyte β 3 -AR, which enhances β 3 -AR-caused inhibition of myocyte contractile, relaxation and [Ca 2+ ] iT and exacerbates β-AR desensitization, thereby directly contributing to the cardiac dysfunction.

Activation of β2 adrenergic receptor signaling modulates inflammation: a target limiting the progression of kidney diseases.

Beta 2 adrenergic receptor (β2-AR)-agonists, widely used as bronchodilators, have demonstrated wide-spectrum anti-inflammatory properties in both immune and non-immune cells in various tissues. Their anti-inflammatory properties are mediated primarily, but not exclusively, via activation of the canonical β2-AR signaling pathway (β2-AR/cAMP/PKA). As non-canonical β2-AR signaling also occurs, several inconsistent findings on the anti-inflammatory effect of β2-agonists are notably present. Increasing amounts of evidence have unveiled the alternative mechanisms of the β2-AR agonists in protecting the tissues against injuries, i.e., by augmenting mitochondria biogenesis and SIRT1 activity, and by attenuating fibrotic signaling. This review mainly covers the basic mechanisms of the anti-inflammatory effects of β2-AR activation along with its limitations. Specifically, we summarized the role of β2-AR signaling in regulating kidney function and in mediating the progression of acute and chronic kidney diseases. Given their versatile protective effects, β2-agonists can be a promising avenue in the treatment of kidney diseases.

Alpha adrenergic receptor signaling in the hypothalamic paraventricular nucleus is diminished by the chronic intermittent hypoxia model of sleep apnea

Chronic intermittent hypoxia (CIH) is a model for obstructive sleep apnea. The paraventricular nucleus (PVN) of the hypothalamus has been suggested to contribute to CIH-induced exaggerated cardiorespiratory reflexes, sympathoexcitation and hypertension. This may occur, in part, via activation of the dense catecholaminergic projections to the PVN that originate in the brainstem. However, the contribution of norepinephrine (NE) and activation of its alpha-adrenergic receptors (α-ARs) in the PVN after CIH exposure is unknown. We hypothesized CIH would increase the contribution of catecholaminergic input. To test this notion, we determined the expression of α-AR subtypes, catecholamine terminal density, and synaptic properties of PVN parvocellular neurons in response to α-AR activation in male Sprague-Dawley normoxic (Norm) and CIH exposed rats. CIH decreased mRNA for α1d and α2b AR. Dopamine-β-hydroxylase (DβH) terminals in the PVN were similar between groups. NE and the α1-AR agonist phenylephrine (PE) increased sEPSC frequency after Norm but not CIH. Block of α1-ARs with prazosin alone did not alter sEPSCs after either Norm or CIH but did prevent agonist augmentation of sEPSC frequency following normoxia. These responses to NE were mimicked by PE during action potential block suggesting presynaptic terminal alterations in CIH. Altogether, these results demonstrate that α1-AR activation participates in neuronal responses in Norm, but are attenuated after CIH. These results may provide insight into the cardiovascular, respiratory and autonomic nervous systems alterations in obstructive sleep apnea.

Patients with pheochromocytoma exhibit low aldosterone renin ratio-preliminary reports

BackgroundPlasma renin activity (PRA) is generally increased in patients with pheochromocytoma (PCC) due to low circulating plasma volume and activation of β-1 adrenergic receptor signaling. However, there has been no study on the aldosterone renin ratio (ARR) in patients with PCC. To elucidate the issue, this study aimed to determine the PRA, plasma aldosterone concentration (PAC), and ARR in patients with PCC and compare them with those in patients with subclinical Cushing’s syndrome (SCS) and non-functioning adrenal adenoma (NFA).MethodsIn this retrospective single-center, cross-sectional study, 67 consecutive patients with adrenal tumors (PCC (n = 18), SCS (n = 18), and NFA (n = 31)) diagnosed at Kobe University Hospital between 2008 and 2014 were enrolled.ResultsPRA was significantly higher in patients with PCC than in those with SCS and NFA (2.1 (1.3 ~ 2.8) vs. 0.7 (0.5 ~ 1.8) and 0.9 (0.6 ~ 1.4) ng/mL/h; p = 0.018 and p = 0.025). Although PACs were comparable among the three groups, ARR was significantly lower in patients with PCC than in those with SCS and NFA (70.5 (45.5 ~ 79.5) vs. 156.0 (92.9 ~ 194.5) and 114.9 (90.1 ~ 153.4); p = 0.001 and p < 0.001). Receiver operating characteristic curve analysis demonstrated that, in differentiating PCC from NFA, PRA > 1.55 ng/mL/h showed a sensitivity of 70.0% and specificity of 80.6%. Interestingly, ARR < 95.4 showed a sensitivity of 83.3% and specificity of 86.7%, which were higher than those in PRA.ConclusionsARR decreased in patients with PCC, which was a more sensitive marker than PRA. Further study is necessary to understand the usefulness of this convenient marker in the detection of PCC.Trial registrationThis study was not registered because of the retrospective analysis.

β2 -adrenergic receptor signaling drives prostate cancer progression by targeting the Sonic hedgehog-Gli1 signaling activation.

BackgroundConsiderable evidence suggests that the sympathetic nervous system, mainly via adrenergic signaling, contributes to prostate cancer (PCa) progression. However, the underlying molecular mechanisms remain unknown.MethodsThe expression level of β2‐adrenergic receptor (β2‐AR) in tissue microarray was evaluated by immunohistochemistry. The effects of isoproterenol (ISO) or Sonic Hedgehog (Shh) signaling inhibitor on tumor growth were analyzed in proliferation and colony formation assays. The apoptosis of cells was analyzed by flow cytometry. Small hairpin RNA‐based knockdown of β2‐AR or Gli1 was validated by Western blot analysis and real‐time PCR. Effects of β2‐AR on prostate carcinogenesis in vivo were observed in a mouse xenograft model. The expression levels of the indicated proteins in xenograft tissues were evaluated by immunohistochemistry. Expression levels of Shh signaling components and downstream proteins were assessed by immunoblotting.ResultsWe determined that β2‐AR was expressed at significantly higher levels in carcinoma than in normal prostate tissues. β2‐AR signaling also played an essential role in sustaining PCa cell proliferation in vivo and in vitro. We also found that inhibition of Shh signaling or knockdown of Gli1 expression significantly restrained ISO‐induced cell proliferation in vitro. ISO alleviated the apoptosis induced by suppressing or knocking down of Gli1. The β2‐AR agonist ISO upregulated the transcription and protein expression of target genes of Shh signaling, including c‐Myc, Cyclin D1, and VEGFA. Conversely, knocking down β2‐AR markedly suppressed the expression of Shh components in vivo and in vitro. In Gli1 knockdown cells, ISO failed to increase the expression of target genes of Shh signaling.ConclusionsIn this study, we uncovered an important role of β2‐AR signaling in regulating the Shh pathway activity in PCa tumorigenesis and provide further insight into the mechanism of the involvement of the Hh signaling pathway. Furthermore, given the efficacy of β2‐adrenergic modulation on PCa, our study might also add evidence for potential therapeutic options of β‐blockers for PCa.

Downregulation of USP33 inhibits Slit/Robo signaling pathway and is associated with poor patient survival of glioma.

Gliomas are the most common malignant tumors in the central nervous system originating from brain glial cells. Although characterized as highly invasive and highly malignant, few molecular targeting therapies have been developed. Ubiquitin Specific Protease 33 (USP33), a gene encoding a deubiquinating enzyme important in a variety of processes, including Slit-dependent cell migration and beta-2 adrenergic receptor signaling, participates in the development of several malignant tumors, however, its role in the development of glioma has not been evaluated. Real-time quantitative PCR was performed to examine the expression of USP33 in glioma tissues and cell lines. Immunohistochemistry was performed to determine USP33 expressions in glioma tissue microarray. Transwell assay was performed to analyze the effect of USP33 on glioma cell line migration. The Kaplan-Meier method and log rank test were applied to evaluate the prognostic value of USP33 expression. Univariate and multivariate Cox proportional hazard regression models were used to identify the independent prognostic factors associated with overall survival (OS) or disease-free survival. The present study demonstrated that USP33 expression was significantly downregulated in glioma tissues. Lower expression of USP33 was associated with a poorer patient disease-free survival and overall survival. In vitro studies revealed that overexpression of USP33 significantly inhibited the migration ability of glioma cells. Mechanistically, USP33 inhibits glioma cell migration by regulating the function of Slit/Robo signaling pathway. Downregulation of USP33 is associated with poor patient survival of glioma. USP33 inhibits glioma cell migration by Slit/Robo signaling pathway. This mechanism may be applied for development of targeting therapy especially for the high-grade glioma.

Adrenergic receptors and cardiovascular diseases

<p indent=0mm>The sympatheticoadreno-medullary system plays a critical role in regulating cardiovascular activity, and adrenergic receptors are the gateway to this role. Adrenergic receptors are representative receptors of the G protein-coupled receptor family and mediate important physiological signaling. The abnormality of the adrenergic receptor signaling system is the main mechanism leading to many cardiovascular diseases, so it is also the main target of clinical drug. In this review, we summarize the discovery of adrenergic receptors as well as their research progress, and review the relationship between the adrenergic receptor signal transduction and cardiovascular diseases. It provides a theoretical basis for the further study of adrenergic receptors and the treatment of cardiovascular diseases.

How does stellate ganglion block alleviate immunologically-linked disorders?

BackgroundThe stellate ganglion is an autonomic nervous ganglion, formed by the fusion of the inferior cervical sympathetic ganglion and the first thoracic sympathetic ganglion, which is present in about 80% of people. It is anterior to the neck of the first rib and contains neurons that supply sympathetic innervation to the head and neck. Injection of local anesthetics near the stellate ganglion (stellate ganglion block; SGB) has been used for multiple clinical indications including sympathetic-mediated pain and vascular insufficiency syndromes of the upper extremity. In addition, reports on SGB having significant impact on conditions linked to immune dysfunction have been published for a century, but the mechanisms of SGB action have been poorly understood. HypothesisSGB hinders the sympathetic innervation of the immune organs, thus modulating the immune system activity and leading to the alleviation of the disease. EvidenceAll primary (thymus and bone marrow) and secondary immune organs (spleen, lymph nodes, mucosa-associated lymphoid tissue) receive a substantial sympathetic innervation, with norepinephrine (NE), as the main neurotransmitter. Complementarily, T and B lymphocytes express β2-adrenergic receptors, while innate immune cells express both α- and β-adrenergic receptors. The consequences of adrenergic receptor signaling can be summarized as immuno-modulatory. Activation of adrenergic receptors leads to decreased levels of pro-inflammatory cytokines (e.g. IL-1β, IL-6, TNF-α) and increased levels of anti-inflammatory cytokines, like IL-10 or TGF-β. Cellular changes include increase in the number of regulatory T cells and shift of the Th1/Th2 balance towards the Th2 response. Since the changes in immune response are global, the explanation has to include generalization of the SGB effect. A likely explanation includes centripetal neuronal pathways between the stellate ganglion and deep brain regions such as insula, amygdala, and hippocampus. Those, in turn, have reciprocal innervation with locus ceruleus, a brain-stem structure involved in the control of the autonomous nervous system. ConclusionVarious pathologic conditions have been shown to be SGB responsive, where the symptoms have been reduced or eliminated. Many of those clinical improvements have been mirrored by measurable immunologic changes. A plausible explanation, consistent with the evidence available so far, is that SGB exerts its effects by regulating the immune system, through a central, reflex-like pathway. Our hypothesis provides a theoretical framework for understanding the effects of SGB and could, thus lead to wider usage of the technique in immune-linked disorders such as ulcerative colitis.