-
Nature Communications Mar 2024G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins and are important drug targets. The discovery of drugs targeting these receptors...
G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins and are important drug targets. The discovery of drugs targeting these receptors and their G protein signaling properties are based on assays mainly performed with modified receptors expressed in heterologous cells. However, GPCR responses may differ in their native environment. Here, by using highly sensitive G sensors, we reveal specific properties of G protein-mediated responses triggered by GABA, α adrenergic and cannabinoid CB1 receptors in primary neurons, different from those in heterologous cells. These include different profiles in the G protein subtypes-mediated responses, and differences in the potencies of some ligands even at similar receptor expression levels. Altogether, our results show the importance of using biosensors compatible with primary cells for evaluating the activities of endogenous GPCRs in their native environment.
Topics: Neurons; Receptors, G-Protein-Coupled; Signal Transduction; Adrenergic Agents; Biological Assay; GTP-Binding Protein alpha Subunits, Gi-Go
PubMed: 38443355
DOI: 10.1038/s41467-024-46177-z -
Circulation Research Nov 2023βAR (beta-1 adrenergic receptor) and βAR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and...
BACKGROUND
βAR (beta-1 adrenergic receptor) and βAR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and heart failure progression. However, the mechanism regulating spatial localization and functional compartmentation of cardiac β-ARs remains elusive. Emerging evidence suggests that microtubule-dependent trafficking of mRNP (messenger ribonucleoprotein) and localized protein translation modulates protein compartmentation in cardiomyocytes. We hypothesized that β-AR compartmentation in cardiomyocytes is accomplished by selective trafficking of its mRNAs and localized translation.
METHODS
The localization pattern of β-AR mRNA was investigated using single molecule fluorescence in situ hybridization and subcellular nanobiopsy in rat cardiomyocytes. The role of microtubule on β-AR mRNA localization was studied using vinblastine, and its effect on receptor localization and function was evaluated with immunofluorescent and high-throughput Förster resonance energy transfer microscopy. An mRNA protein co-detection assay identified plausible β-AR translation sites in cardiomyocytes. The mechanism by which β-AR mRNA is redistributed post-heart failure was elucidated by single molecule fluorescence in situ hybridization, nanobiopsy, and high-throughput Förster resonance energy transfer microscopy on 16 weeks post-myocardial infarction and detubulated cardiomyocytes.
RESULTS
βAR and βAR mRNAs show differential localization in cardiomyocytes, with βAR found in the perinuclear region and βAR showing diffuse distribution throughout the cell. Disruption of microtubules induces a shift of βAR transcripts toward the perinuclear region. The close proximity between βAR transcripts and translated proteins suggests that the translation process occurs in specialized, precisely defined cellular compartments. Redistribution of βAR transcripts is microtubule-dependent, as microtubule depolymerization markedly reduces the number of functional receptors on the membrane. In failing hearts, both βAR and βAR mRNAs are redistributed toward the cell periphery, similar to what is seen in cardiomyocytes undergoing drug-induced detubulation. This suggests that t-tubule remodeling contributes to β-AR mRNA redistribution and impaired βAR function in failing hearts.
CONCLUSIONS
Asymmetrical microtubule-dependent trafficking dictates differential βAR and βAR localization in healthy cardiomyocyte microtubules, underlying the distinctive compartmentation of the 2 β-ARs on the plasma membrane. The localization pattern is altered post-myocardial infarction, resulting from transverse tubule remodeling, leading to distorted βAR-mediated cyclic adenosine monophosphate signaling.
Topics: Rats; Animals; In Situ Hybridization, Fluorescence; Heart Failure; Receptors, Adrenergic, beta-2; Myocardial Infarction; Myocytes, Cardiac; Cyclic AMP; Receptors, Adrenergic, beta-1; Microtubules; RNA, Messenger; Adenosine Monophosphate
PubMed: 37869877
DOI: 10.1161/CIRCRESAHA.123.323174 -
Cureus Sep 2023Post-traumatic stress disorder (PTSD) is a complex mental health condition affecting individuals exposed to traumatic events. This paper is a narrative review of the... (Review)
Review
Post-traumatic stress disorder (PTSD) is a complex mental health condition affecting individuals exposed to traumatic events. This paper is a narrative review of the existing literature on pharmacological and psychotherapeutic interventions for PTSD. Treatment includes selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and alpha-1 adrenergic receptor antagonists. By exploring the outcomes of these interventions, the review seeks to provide valuable insights into their potential as PTSD treatment options. The paper also highlights the importance of tailoring treatment plans to individual needs and discusses emerging treatments, such as mindfulness-based therapies, virtual reality therapy, and neurostimulation techniques. By integrating findings from various studies, it aims to offer valuable information to optimize treatment strategies and enhance outcomes for individuals suffering from PTSD. The goal is to support informed decision-making, ultimately leading to more effective and tailored approaches to address the challenges posed by this debilitating condition.
PubMed: 37814755
DOI: 10.7759/cureus.44905 -
Autonomic Neuroscience : Basic &... Feb 2024Cancer cachexia, characterized by muscle wasting and widespread inflammation, poses a significant challenge for patients with cancer, profoundly impacting both their... (Review)
Review
Cancer cachexia, characterized by muscle wasting and widespread inflammation, poses a significant challenge for patients with cancer, profoundly impacting both their quality of life and treatment management. However, existing treatment modalities remain very limited, accentuating the necessity for innovative therapeutic interventions. Many recent studies demonstrated that changes in autonomic balance is a key driver of cancer cachexia. This review consolidates research findings from investigations into autonomic dysfunction across cancer cachexia, spanning animal models and patient cohorts. Moreover, we explore therapeutic strategies involving adrenergic receptor modulation through receptor blockers and agonists. Mechanisms underlying adrenergic hyperactivity in cardiac and adipose tissues, influencing tissue remodeling, are also examined. Looking ahead, we present a perspective for future research that delves into autonomic dysregulation in cancer cachexia. This comprehensive review highlights the urgency of advancing research to unveil innovative avenues for combatting cancer cachexia and improving patient well-being.
Topics: Animals; Humans; Cachexia; Muscle, Skeletal; Adrenergic Agents; Quality of Life; Neoplasms; Autonomic Nervous System Diseases
PubMed: 38071925
DOI: 10.1016/j.autneu.2023.103136 -
Hellenic Journal of Cardiology : HJC =... 2023Duchenne muscular dystrophy is a fatal X-linked recessive disease affecting approximately 1 in 3500 births. It is characterized by a genetic lack of dystrophin, which is... (Review)
Review
Duchenne muscular dystrophy is a fatal X-linked recessive disease affecting approximately 1 in 3500 births. It is characterized by a genetic lack of dystrophin, which is an essential protein for maintaining muscle integrity. The lack of dystrophin plays a pathophysiological role in the development of dilated cardiomyopathy in Duchenne muscular dystrophy. Currently, no consensus exists on specific pharmacological therapy guidelines for these patients; however, it centers around the guidelines for heart failure management. This systematic review investigated 12 randomized control trials dating back to 2005 in the pharmacotherapy of patients with dilated cardiomyopathy Duchenne muscular dystrophy. This review specifically included angiotensin-converting enzyme inhibitors, aldosterone receptor blockers, angiotensin receptor/neprilysin inhibitors, beta-blockers, and mineralocorticoid receptor antagonists. Despite their limitations, these studies have shown promising effects in improving the overall heart function and prognosis in patients with this condition. However, to attain higher statistical significance, future studies should investigate larger populations and for longer periods.
Topics: Humans; Cardiomyopathy, Dilated; Muscular Dystrophy, Duchenne; Dystrophin; Angiotensin-Converting Enzyme Inhibitors; Adrenergic beta-Antagonists
PubMed: 37406964
DOI: 10.1016/j.hjc.2023.06.007 -
Clinical Practice and Epidemiology in... 2023Depressive disorders (DD) are common, and their prevalence is expected to rise over the next decade. Depressive disorders are linked to significant morbidity and... (Review)
Review
Depressive disorders (DD) are common, and their prevalence is expected to rise over the next decade. Depressive disorders are linked to significant morbidity and mortality. The clinical conundrum of depressive disorders lies in the heterogeneity of their phenomenology and etiology. Further, the currently available antidepressants have several limitations, including a delayed onset of action, limited efficacy, and an unfavorable side effect profile. In this review, Dexmedetomidine (DEX), a highly selective and potent α2-adrenergic receptor (α2-AR) agonist, is proposed as a potentially novel antidepressant with multiple mechanisms of action targeting various depression pathophysiological processes. These mechanisms include modulation of the noradrenergic system, regulation of neuroinflammation and oxidative stress, influence on the Brain-Derived Neurotrophic Factor (BDNF) levels, and modulation of neurotransmitter systems, such as glutamate. The review begins with an introduction before moving on to a discussion of DEX's pharmacological features. The pathophysiological and phenomenological targets of DD are also explored, along with the review of the existing preclinical and clinical evidence for DEX's putative anti-depressant effects. Finally, the review ends by presenting the pertinent conclusions and future directions.
PubMed: 37916205
DOI: 10.2174/17450179-v19-230823-2023-4 -
Molecular Metabolism Aug 2023Norepinephrine stimulates the adipose tissue thermogenic program through a β-adrenergic receptor (βAR)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA)...
OBJECTIVE
Norepinephrine stimulates the adipose tissue thermogenic program through a β-adrenergic receptor (βAR)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling cascade. We discovered that a noncanonical activation of the mechanistic target of rapamycin complex 1 (mTORC1) by PKA is required for the βAR-stimulation of adipose tissue browning. However, the downstream events triggered by PKA-phosphorylated mTORC1 activation that drive this thermogenic response are not well understood.
METHODS
We used a proteomic approach of Stable Isotope Labeling by/with Amino acids in Cell culture (SILAC) to characterize the global protein phosphorylation profile in brown adipocytes treated with the βAR agonist. We identified salt-inducible kinase 3 (SIK3) as a candidate mTORC1 substrate and further tested the effect of SIK3 deficiency or SIK inhibition on the thermogenic gene expression program in brown adipocytes and in mouse adipose tissue.
RESULTS
SIK3 interacts with RAPTOR, the defining component of the mTORC1 complex, and is phosphorylated at Ser in a rapamycin-sensitive manner. Pharmacological SIK inhibition by a pan-SIK inhibitor (HG-9-91-01) in brown adipocytes increases basal Ucp1 gene expression and restores its expression upon blockade of either mTORC1 or PKA. Short-hairpin RNA (shRNA) knockdown of Sik3 augments, while overexpression of SIK3 suppresses, Ucp1 gene expression in brown adipocytes. The regulatory PKA phosphorylation domain of SIK3 is essential for its inhibition. CRISPR-mediated Sik3 deletion in brown adipocytes increases type IIa histone deacetylase (HDAC) activity and enhances the expression of genes involved in thermogenesis such as Ucp1, Pgc1α, and mitochondrial OXPHOS complex protein. We further show that HDAC4 interacts with PGC1α after βAR stimulation and reduces lysine acetylation in PGC1α. Finally, a SIK inhibitor well-tolerated in vivo (YKL-05-099) can stimulate the expression of thermogenesis-related genes and browning of mouse subcutaneous adipose tissue.
CONCLUSIONS
Taken together, our data reveal that SIK3, with the possible contribution of other SIKs, functions as a phosphorylation switch for β-adrenergic activation to drive the adipose tissue thermogenic program and indicates that more work to understand the role of the SIKs is warranted. Our findings also suggest that maneuvers targeting SIKs could be beneficial for obesity and related cardiometabolic disease.
Topics: Mice; Animals; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Proteomics; Adipose Tissue; Adipocytes, Brown; Receptors, Adrenergic, beta; Mechanistic Target of Rapamycin Complex 1; Thermogenesis; Protein Serine-Threonine Kinases
PubMed: 37321371
DOI: 10.1016/j.molmet.2023.101753 -
Advanced Science (Weinheim,... Apr 2024Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease but effective drugs for treatment of AAA are still lacking. Recently, erythropoietin (EPO) is...
Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease but effective drugs for treatment of AAA are still lacking. Recently, erythropoietin (EPO) is reported to induce AAA formation in apolipoprotein-E knock out (ApoE) mice but an effective antagonist is unknown. In this study, formoterol, a β2 adrenergic receptor (β2AR) agonist, is found to be a promising agent for inhibiting AAA. To test this hypothesis, ApoE mice are treated with vehicle, EPO, and EPO plus low-, medium-, and high-dose formoterol, respectively. The incidence of AAA is 0, 55%, 35%,10%, and 55% in these 5 groups, respectively. Mechanistically, senescence of vascular smooth muscle cell (VSMC) is increased by EPO while decreased by medium-dose formoterol both in vivo and in vitro, manifested by the altered expression of senescence biomarkers including phosphorylation of H2AX, senescence-associated β-galactosidase activity, and P21 protein level. In addition, expression of sirtuin 1 (SIRT1) in aorta is decreased in EPO-induced AAA but remarkably elevated by medium-dose formoterol. Knockdown of β2AR and blockage of cyclic adenosine monophosphate (cAMP) attenuate the inhibitory role of formoterol in EPO-induced VSMC senescence. In summary, medium-dose formoterol attenuates EPO-induced AAA via β2AR/cAMP/SIRT1 pathways, which provides a promising medication for the treatment of AAA.
Topics: Animals; Mice; Aortic Aneurysm, Abdominal; Apolipoproteins E; Erythropoietin; Formoterol Fumarate; Sirtuin 1
PubMed: 38353392
DOI: 10.1002/advs.202306232 -
Nature Communications Aug 2023α-adrenergic receptors (α-ARs) play critical roles in the cardiovascular and nervous systems where they regulate blood pressure, cognition, and metabolism. However,...
α-adrenergic receptors (α-ARs) play critical roles in the cardiovascular and nervous systems where they regulate blood pressure, cognition, and metabolism. However, the lack of specific agonists for all α subtypes has limited our understanding of the physiological roles of different α-AR subtypes, and led to the stagnancy in agonist-based drug development for these receptors. Here we report cryo-EM structures of α-AR in complex with heterotrimeric G-proteins and either the endogenous common agonist epinephrine or the α-AR-specific synthetic agonist A61603. These structures provide molecular insights into the mechanisms underlying the discrimination between α-AR and α-AR by A61603. Guided by the structures and corresponding molecular dynamics simulations, we engineer α-AR mutants that are not responsive to A61603, and α-AR mutants that can be potently activated by A61603. Together, these findings advance our understanding of the agonist specificity for α-ARs at the molecular level, opening the possibility of rational design of subtype-specific agonists.
Topics: Receptors, Adrenergic, alpha-1; Epinephrine; Signal Transduction
PubMed: 37563160
DOI: 10.1038/s41467-023-40524-2 -
The Journal of Clinical Investigation Oct 2023Stimulation of adipocyte β-adrenergic receptors (β-ARs) induces expression of uncoupling protein 1 (UCP1), promoting nonshivering thermogenesis. Association of β-ARs...
Stimulation of adipocyte β-adrenergic receptors (β-ARs) induces expression of uncoupling protein 1 (UCP1), promoting nonshivering thermogenesis. Association of β-ARs with a lysine-myristoylated form of A kinase-anchoring protein 12 (AKAP12, also known as gravin-α) is required for downstream signaling that culminates in UCP1 induction. Conversely, demyristoylation of gravin-α by histone deacetylase 11 (HDAC11) suppresses this pathway. Whether inhibition of HDAC11 in adipocytes is sufficient to drive UCP1 expression independently of β-ARs is not known. Here, we demonstrate that adipocyte-specific deletion of HDAC11 in mice leads to robust induction of UCP1 in adipose tissue (AT), resulting in increased body temperature. These effects are mimicked by treating mice in vivo or human AT ex vivo with an HDAC11-selective inhibitor, FT895. FT895 triggers biphasic, gravin-α myristoylation-dependent induction of UCP1 protein expression, with a noncanonical acute response that is posttranscriptional and independent of protein kinase A (PKA), and a delayed response requiring PKA activity and new Ucp1 mRNA synthesis. Remarkably, HDAC11 inhibition promotes UCP1 expression even in models of adipocyte catecholamine resistance where β-AR signaling is blocked. These findings define cell-autonomous, multimodal roles for HDAC11 as a suppressor of thermogenesis, and highlight the potential of inhibiting HDAC11 to therapeutically alter AT phenotype independently of β-AR stimulation.
Topics: Animals; Humans; Mice; Adipocytes; Adipose Tissue; Adipose Tissue, Brown; Catecholamines; Histone Deacetylases; Thermogenesis; Uncoupling Protein 1; Histone Deacetylase Inhibitors
PubMed: 37607030
DOI: 10.1172/JCI168192