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Journal of Biomedical Science Jul 2023Sustained, chronic activation of β-adrenergic receptor (β-AR) signaling leads to cardiac arrhythmias, with exchange proteins directly activated by cAMP (Epac1 and...
BACKGROUND
Sustained, chronic activation of β-adrenergic receptor (β-AR) signaling leads to cardiac arrhythmias, with exchange proteins directly activated by cAMP (Epac1 and Epac2) as key mediators. This study aimed to evaluate whether CD44, a transmembrane receptor mediating various cellular responses, participates in Epac-dependent arrhythmias.
METHODS
The heart tissue from CD44 knockout (CD44) mice, cultured HL-1 myocytes and the tissue of human ventricle were used for western blot, co-immunoprecipitaiton and confocal studies. Line-scanning confocal imaging was used for the study of cellular Ca sparks on myocytes. Optical mapping and intra-cardiac pacing were applied for arrhythmia studies on mice's hearts.
RESULTS
In mice, isoproterenol, a β-AR agonist, upregulated CD44 and Epac1 and increased the association between CD44 and Epac1. Isoproterenol upregulated the expression of phospho-CaMKII (p-CaMKII), phospho-ryanodine receptor (p-RyR), and phospho-phospholamban (p-PLN) in mice and cultured myocytes; these effects were attenuated in CD44 mice compared with wild-type controls. In vitro, isoproterenol, 8-CPT-cAMP (an Epac agonist), and osteopontin (a ligand of CD44) significantly upregulated the expression of p-CaMKII, p-RyR, and p-PLN; this effect was attenuated by CD44 small interfering RNA (siRNA). In myocytes, resting Ca sparks were induced by isoproterenol and overexpressed CD44, which were prevented by inhibiting CD44. Ex vivo optical mapping and in vivo intra-cardiac pacing studies showed isoproterenol-induced triggered events and arrhythmias in ventricles were prevented in CD44 mice. The inducibility of ventricular arrhythmias (VAs) was attenuated in CD44 HF mice compared with wild-type HF controls. In patients, CD44 were upregulated, and the association between CD44 and Epac1 were increased in ventricles with reduced contractility.
CONCLUSION
CD44 regulates β-AR- and Epac1-mediated Ca-handling abnormalities and VAs. Inhibition of CD44 is effective in reducing VAs in HF, which is potentially a novel therapeutic target for preventing the arrhythmias and sudden cardiac death in patients with diseased hearts.
Topics: Humans; Mice; Animals; Receptors, Adrenergic, beta; Isoproterenol; Guanine Nucleotide Exchange Factors; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Myocytes, Cardiac; Calcium; Arrhythmias, Cardiac; Calcium Signaling; Adrenergic Agents; Hyaluronan Receptors
PubMed: 37452346
DOI: 10.1186/s12929-023-00944-0 -
Experimental Gerontology Jul 2023Aging is one of the primary risk factors for the development of type 2 diabetes and cardiovascular disease, and regular physical activity can help to delay, prevent, or... (Review)
Review
Aging is one of the primary risk factors for the development of type 2 diabetes and cardiovascular disease, and regular physical activity can help to delay, prevent, or manage the onset and development of many chronic diseases present in older adults. Brown adipose tissue (BAT) is thermogenic tissue that protects against age-related disease, but BAT activity decreases with age. In this review, we discuss how aging contributes to impaired BAT function by inducing a 'whitening' of the BAT and altering beta 3 adrenergic receptor (βAR) signaling, uncoupling protein 1 (UCP1) gene expression, and mitochondria respiration, and potential mechanisms for exercise to counteract the effects of aging on BAT.
Topics: Humans; Aged; Adipose Tissue, Brown; Diabetes Mellitus, Type 2; Thermogenesis; Exercise
PubMed: 37224933
DOI: 10.1016/j.exger.2023.112218 -
JACC. Basic To Translational Science Aug 2023The decrease in β-adrenergic receptor responsiveness in heart failure is attributed conventionally to agonist-dependent desensitization. We identify elastase-dependent...
The decrease in β-adrenergic receptor responsiveness in heart failure is attributed conventionally to agonist-dependent desensitization. We identify elastase-dependent β-adrenergic receptor cleavage as a novel proteolytic mechanism that disrupts β-adrenergic receptor responsiveness in the setting of tissue injury or inflammation.
PubMed: 37719436
DOI: 10.1016/j.jacbts.2023.02.002 -
Circulation Research Dec 2023Nitric oxide (NO) has been identified as a signaling molecule generated during β-adrenergic receptor stimulation in the heart. Furthermore, a role for NO in triggering...
BACKGROUND
Nitric oxide (NO) has been identified as a signaling molecule generated during β-adrenergic receptor stimulation in the heart. Furthermore, a role for NO in triggering spontaneous Ca release via -nitrosylation of CaMKIIδ (Ca/calmodulin kinase II delta) is emerging. NO donors are routinely used clinically for their cardioprotective effects on the heart, but it is unknown how NO donors modulate the proarrhythmic CaMKII to alter cardiac arrhythmia incidence. We test the role of -nitrosylation of CaMKIIδ at the Cysteine-273 inhibitory site and cysteine-290 activating site in cardiac Ca handling and arrhythmogenesis before and during β-adrenergic receptor stimulation.
METHODS
We measured Ca-handling in isolated cardiomyocytes from C57BL/6J wild-type (WT) mice and mice lacking CaMKIIδ expression (CaMKIIδ-KO) or with deletion of the -nitrosylation site on CaMKIIδ at cysteine-273 or cysteine-290 (CaMKIIδ-C273S and -C290A knock-in mice). Cardiomyocytes were exposed to NO donors, -nitrosoglutathione (GSNO; 150 μM), sodium nitroprusside (200 μM), and β-adrenergic agonist isoproterenol (100 nmol/L).
RESULTS
Both WT and CaMKIIδ-KO cardiomyocytes responded to isoproterenol with a full inotropic and lusitropic Ca transient response as well as increased Ca spark frequency. However, the increase in Ca spark frequency was significantly attenuated in CaMKIIδ-KO cardiomyocytes. The protection from isoproterenol-induced Ca sparks and waves was mimicked by GSNO pretreatment in WT cardiomyocytes but lost in CaMKIIδ-C273S cardiomyocytes. When GSNO was applied after isoproterenol, this protection was not observed in WT or CaMKIIδ-C273S but was apparent in CaMKIIδ-C290A. In Langendorff-perfused isolated hearts, GSNO pretreatment limited isoproterenol-induced arrhythmias in WT but not CaMKIIδ-C273S hearts, while GSNO exposure after isoproterenol sustained or exacerbated arrhythmic events.
CONCLUSIONS
We conclude that prior -nitrosylation of CaMKIIδ at cysteine-273 can limit subsequent β-adrenergic receptor-induced arrhythmias, but that -nitrosylation at cysteine-290 might worsen or sustain β-adrenergic receptor-induced arrhythmias. This has important implications for the administration of NO donors in the clinical setting.
Topics: Mice; Animals; Isoproterenol; Nitric Oxide; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cysteine; Mice, Inbred C57BL; Arrhythmias, Cardiac; Myocytes, Cardiac; Phosphorylation; Receptors, Adrenergic, beta; Calcium; Sarcoplasmic Reticulum
PubMed: 37961889
DOI: 10.1161/CIRCRESAHA.123.323571 -
Biomolecules Jan 2024Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic... (Review)
Review
Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic activities, such as thermogenesis and lipolysis in brown and white adipose tissue, respectively (BAT, WAT), negative inotropic effects in cardiomyocytes, and relaxation of the blood vessels and the urinary bladder. The β3-AR has been suggested as a potential target for cancer treatment, both in adult and pediatric tumors, since under hypoxia its upregulation in the tumor microenvironment (TME) regulates stromal cell differentiation, tumor growth and metastases, signifying that its agonism/antagonism could be useful for clinical benefits. Promising results in cancer research have proposed the β3-AR being targeted for the treatment of many conditions, with some drugs, at present, undergoing phase II and III clinical trials. In this review, we report the scientific journey followed by the research from the β3-Ars' discovery, with focus on the β3-Ars' role in cancer initiation and progression that elects it an intriguing target for novel antineoplastic approaches. The overview highlights the great potential of the β3-AR, both in physiologic and pathologic conditions, with the intention to display the possible benefits of β3-AR modulation in cancer reality.
Topics: Adult; Child; Humans; Adipose Tissue, Brown; Adipose Tissue, White; Lipolysis; Receptors, Adrenergic, beta-3; Neoplasms
PubMed: 38397396
DOI: 10.3390/biom14020159 -
Journal of Clinical Medicine Nov 2023Obesity is becoming a global health epidemic. Brown and "beige" adipose tissue may produce heat, leading to energy expenditure enhancement and weight loss. Mirabegron, a... (Review)
Review
Obesity is becoming a global health epidemic. Brown and "beige" adipose tissue may produce heat, leading to energy expenditure enhancement and weight loss. Mirabegron, a selective β3-adrenergic receptor agonist, has been found to be effective as a brown adipose tissue activator, a "beige" cells stimulator and a metabolic homeostasis controller in animal and human studies. Although in animal studies, administration of mirabegron led to obesity improvement, significant weight loss in obese patients after mirabegron treatment has not been demonstrated so far, which may be associated with the too-short duration of the trials and the small number of participants in the studies. In humans, the most effective treatment for adipose tissue stimulation was high doses of mirabegron; however, cardiovascular side effects may limit the use of such doses, so the long-term safety must be evaluated. In cases of tachycardia or blood pressure elevation, the co-administration of a β1-adrenergic receptor blocker may be useful. It should be checked whether smaller doses of mirabegron, taken for a longer time, will be sufficient to stimulate brown and "beige" adipose tissue, leading to weight loss. The introduction of mirabegron into obesity treatment in the future will require long-term trials with larger numbers of subjects, to assess mirabegron efficacy, tolerability, and safety.
PubMed: 37959362
DOI: 10.3390/jcm12216897 -
Sympathetic activity regulates epithelial proliferation and wound healing via adrenergic receptor α.Scientific Reports Oct 2023Innervation of the intestinal mucosa by the sympathetic nervous system is well described but the effects of adrenergic receptor stimulation on the intestinal epithelium...
Innervation of the intestinal mucosa by the sympathetic nervous system is well described but the effects of adrenergic receptor stimulation on the intestinal epithelium remain equivocal. We therefore investigated the effect of sympathetic neuronal activation on intestinal cells in mouse models and organoid cultures, to identify the molecular routes involved. Using publicly available single-cell RNA sequencing datasets we show that the α isoform is the most abundant adrenergic receptor in small intestinal epithelial cells. Stimulation of this receptor with norepinephrine or a synthetic specific α receptor agonist promotes epithelial proliferation and stem cell function, while reducing differentiation in vivo and in intestinal organoids. In an anastomotic healing mouse model, adrenergic receptor α stimulation resulted in improved anastomotic healing, while surgical sympathectomy augmented anastomotic leak. Furthermore, stimulation of this receptor led to profound changes in the microbial composition, likely because of altered epithelial antimicrobial peptide secretion. Thus, we established that adrenergic receptor α is the molecular delegate of intestinal epithelial sympathetic activity controlling epithelial proliferation, differentiation, and host defense. Therefore, this receptor could serve as a newly identified molecular target to improve mucosal healing in intestinal inflammation and wounding.
Topics: Animals; Mice; Cell Proliferation; Epithelial Cells; Intestinal Mucosa; Intestines; Receptors, Adrenergic; Receptors, Adrenergic, alpha-2; Wound Healing
PubMed: 37863979
DOI: 10.1038/s41598-023-45160-w -
Circulation Research Nov 20233', 5'-cyclic AMP (cAMP) regulates numerous cardiac functions. Various hormones and neurotransmitters elevate intracellular cAMP (i[cAMP]) in cardiomyocytes through...
BACKGROUND
3', 5'-cyclic AMP (cAMP) regulates numerous cardiac functions. Various hormones and neurotransmitters elevate intracellular cAMP (i[cAMP]) in cardiomyocytes through activating GsPCRs (stimulatory-G-protein-coupled-receptors) and membrane-bound ACs (adenylyl cyclases). Increasing evidence has indicated that stimulating different GsPCRs and ACs exhibits distinct, even opposite effects, on cardiomyocyte viability. However, the underlying mechanisms are not fully understood.
METHODS
We used molecular and pharmacological approaches to investigate how different GsPCR/cAMP signaling differentially regulate cardiomyocyte viability with in vitro, ex vivo, and in vivo models.
RESULTS
For prodeath GsPCRs, we explored β1AR (beta1-adrenergic receptor) and H2R (histamine-H2-receptor). We found that their prodeath effects were similarly dependent on AC5 activation, ATP release to the extracellular space via PANX1 (pannexin-1) channel, and extracellular ATP (e[ATP])-mediated signaling involving in P2X7R (P2X purinoceptor 7) and CaMKII (Ca/calmodulin-dependent protein kinase II). PANX1 phosphorylation at Serine 206 by cAMP-dependent-PKA (protein-kinase-A) promoted PANX1 activation, which was critical in β1AR- or H2R-induced cardiomyocyte death in vitro and in vivo. β1AR or H2R was localized proximately to PANX1, which permits ATP release. For prosurvival GsPCRs, we explored adenosine-A2-receptor (A2R), CGRPR (calcitonin-gene-related-peptide-receptor), and RXFP1 (relaxin-family peptide-receptor 1). Their prosurvival effects were dependent on AC6 activation, cAMP efflux via MRP4 (multidrug resistance protein 4), extracellular cAMP metabolism to adenosine (e[cAMP]-to-e[ADO]), and e[ADO]-mediated signaling. A2R, CGRPR, or RXFP1 was localized proximately to MRP4, which enables cAMP efflux. Interestingly, exogenously increasing e[cAMP] levels by membrane-impermeable cAMP protected against cardiomyocyte death in vitro and in ex vivo and in vivo mouse hearts with ischemia-reperfusion injuries.
CONCLUSIONS
Our findings indicate that the functional diversity of different GsPCRs in cardiomyocyte viability could be achieved by their ability to form unique signaling complexes (signalosomes) that determine the fate of cAMP: either stimulate ATP release by activating PKA or directly efflux to be e[cAMP].
Topics: Mice; Animals; Cyclic AMP; Myocytes, Cardiac; Adenosine; Cyclic AMP-Dependent Protein Kinases; Adenosine Triphosphate; Multidrug Resistance-Associated Proteins; Peptides
PubMed: 37850368
DOI: 10.1161/CIRCRESAHA.123.322652 -
Molecular Metabolism Aug 2023Free fatty acid receptor 1 (FFAR1) is highly expressed in enteroendocrine cells of the small intestine and pancreatic beta cells, where FFAR1 agonists function as GLP-1...
OBJECTIVE
Free fatty acid receptor 1 (FFAR1) is highly expressed in enteroendocrine cells of the small intestine and pancreatic beta cells, where FFAR1 agonists function as GLP-1 and insulin secretagogues, respectively. Most efficacious are so-called second-generation synthetic agonists such as AM5262, which, in contrast to endogenous long-chain fatty acids are able to signal through both IP/Ca and cAMP pathways. Whereas IP signaling is to be expected for the mainly Gq-coupled FFAR1, the mechanism behind FFAR1-induced cAMP accumulation remains unclear, although originally proposed to be Gs mediated.
METHODS AND RESULTS
When stimulated with AM5262, we observe that FFAR1 can activate the majority of the Gα proteins, except - surprisingly - members of the Gs family. AM5262-induced FFAR1-mediated transcriptional activation through cAMP response element (CREB) was blocked by the specific Gq inhibitor, YM253890. Furthermore, in Gq-deficient cells no CREB signal was observed unless Gq or G11 was reintroduced by transfection. By qPCR we determined that adenylate cyclase 2 (Adcy2) was highly expressed and enriched relative to the nine other Adcys in pro-glucagon expressing enteroendocrine cells. Co-transfection with ADCY2 increased the FFAR1-induced cAMP response 4-5-fold in WT HEK293 cells, an effect fully inhibited by YM253890. Moreover, co-transfection with ADCY2 had no effect in Gq-deficient cells without reintroduction of either Gq or G11. Importantly, although both AM5262/FFAR1 and isoproterenol/β2 adrenergic receptor (β2AR) induced cAMP production was lost in Gs-deficient cells, only the β2AR response was rescued by Gs transfection, whereas co-transfection with ADCY2 was required to rescue the FFAR1 cAMP response. In situ hybridization demonstrated a high degree of co-expression of ADCY2 and FFAR1 in enteroendocrine cells throughout the intestine. Finally, in the enteroendocrine STC-1 and GLUTag cell lines AM5262-induced cAMP accumulation and GLP-1 secretion were both blocked by YM253890.
CONCLUSIONS
Our results show that Gq signaling is responsible not only for the IP/Ca but also the cAMP response, which together are required for the highly efficacious hormone secretion induced by second-generation FFAR1 agonists - and that ADCY2 presumably mediates the Gq-driven cAMP response.
Topics: Humans; Adenylyl Cyclases; Fatty Acids, Nonesterified; HEK293 Cells; Receptors, G-Protein-Coupled; Glucagon-Like Peptide 1
PubMed: 37348738
DOI: 10.1016/j.molmet.2023.101757 -
International Journal of Molecular... Aug 2023The microenvironment of most tumors is complex, comprising numerous aspects of immunosuppression. Several studies have indicated that the adrenergic system is vital for... (Review)
Review
The microenvironment of most tumors is complex, comprising numerous aspects of immunosuppression. Several studies have indicated that the adrenergic system is vital for controlling immunological responses. In the context of the tumor microenvironment, nor-adrenaline (NA) is poured in by innervating nerves and tumor tissues itself. The receptors for nor-adrenaline are present on the surfaces of cancer and immune cells and are often involved in the activation of pro-tumoral signaling pathways. Beta2-adrenergic receptors (β2-ARs) are an emerging class of receptors that are capable of modulating the functioning of immune cells. β2-AR is reported to activate regulatory immune cells and inhibit effector immune cells. Blocking β2-AR increases activation, proliferation, and cytokine release of T lymphocytes. Moreover, β2-AR deficiency during metabolic reprogramming of T cells increases mitochondrial membrane potential and biogenesis. In the view of the available research data, the immunosuppressive role of β2-AR in T cells presents it as a targetable checkpoint in CAR-T cell therapies. In this review, we have abridged the contemporary knowledge about adrenergic-stress-mediated β2-AR activation on T lymphocytes inside tumor milieu.
Topics: Receptors, Chimeric Antigen; T-Lymphocytes; Adrenergic Agents; Norepinephrine; Cell- and Tissue-Based Therapy; Epinephrine
PubMed: 37629018
DOI: 10.3390/ijms241612837