RESUMO
OBJECTIVES: To observe the effect of electroacupuncture (EA) on pain, anxiety like behavior, and substance P(SP) /neurokinin-1 receptor (NK1R) /ß -arrestin 1(ARRB1) pathway related protein expression in hippocampus of chronic constriction injury (CCI) rats, so as to explore its mechanisms underlying improvement of neuropathic pain. METHODS: Twenty-seven male SD rats were randomly divided into sham operation, model and EA groups, with 9 rats in each group. The CCI model was established by ligature of the left sciatic nerve. On the 8th day following modeling, EA (2 Hz, 0.5-1.5 mA) was applied to the left "Huantiao" (GB34) and "Yanglingquan" (GB34) for 30 min, once every other day for 13 times. Mechanical paw withdrawal threshold (MWT), thermal paw withdrawal threshold (TWL) and difference of the weight distribution of the hind limbs were detected before operation and at the 5th, 9th, 17th, 25th and 33rd days after operation. Open field test was used to evaluate the anxiety-like behavior of rats. The content of SP in hippocampus was determined by ELISA. The protein expression of NK1R and ARRB1 in hippocampus was detected by Western blot. RESULTS: Compared with the sham operation group, the MWT and TWL of the left hind limb at the 5th, 9th, 17th, 25th and 33rd days after operation, the time of entering the central area and the total distance of movement, and the content of SP in the hippocampus were significantly decreased (P<0.001, P<0.01), while the difference of the weight distribution of the hind limbs at the 5th, 9th, 17th, 25th and 33rd days after operation and the protein expression of NK1R and ARRB1 were significantly increased (P<0.001, P<0.05) in the model group. After EA intervention, the MWT and TWL of the left hind limb, the time of entering the central area and the total moving distance, and the expression of SP in the hippocampus were significantly increased (P<0.01, P<0.001, P<0.05), while the difference in the weight distribution of the hind limbs was significantly reduced, and the expression of NK1R and ARRB1 protein in the hippocampus were significantly decreased (P<0.001, P<0.05) in the EA group. CONCLUSIONS: EA can effectively improve the pain and anxiety behaviors in CCI rats, and reverse the abnormal expression of SP, NK1R and ARRB1 proteins in the hippocampus, which may be related to its effects in regulating the SP/NK1R/ARRB1 pathway in the hippocampus.
Assuntos
Eletroacupuntura , Hipocampo , Neuralgia , Ratos Sprague-Dawley , Receptores da Neurocinina-1 , Substância P , Animais , Masculino , Ratos , Hipocampo/metabolismo , Neuralgia/terapia , Neuralgia/metabolismo , Neuralgia/genética , Receptores da Neurocinina-1/metabolismo , Receptores da Neurocinina-1/genética , Humanos , Substância P/metabolismo , Substância P/genética , beta-Arrestina 1/metabolismo , beta-Arrestina 1/genética , Pontos de Acupuntura , Transdução de SinaisRESUMO
BACKGROUND: ß-adrenergic receptor (ß-AR) overactivation is a major pathological cue associated with cardiac injury and diseases. AMPK (AMP-activated protein kinase), a conserved energy sensor, regulates energy metabolism and is cardioprotective. However, whether AMPK exerts cardioprotective effects via regulating the signaling pathway downstream of ß-AR remains unclear. METHODS: Using immunoprecipitation, mass spectrometry, site-specific mutation, in vitro kinase assay, and in vivo animal studies, we determined whether AMPK phosphorylates ß-arrestin-1 at serine (Ser) 330. Wild-type mice and mice with site-specific mutagenesis (S330A knock-in [KI]/S330D KI) were subcutaneously injected with the ß-AR agonist isoproterenol (5 mg/kg) to evaluate the causality between ß-adrenergic insult and ß-arrestin-1 Ser330 phosphorylation. Cardiac transcriptomics was used to identify changes in gene expression from ß-arrestin-1-S330A/S330D mutation and ß-adrenergic insult. RESULTS: Metformin could decrease cAMP/PKA (protein kinase A) signaling induced by isoproterenol. AMPK bound to ß-arrestin-1 and phosphorylated Ser330 with the highest phosphorylated mass spectrometry score. AMPK activation promoted ß-arrestin-1 Ser330 phosphorylation in vitro and in vivo. Neonatal mouse cardiomyocytes overexpressing ß-arrestin-1-S330D (active form) inhibited the ß-AR/cAMP/PKA axis by increasing PDE (phosphodiesterase) 4 expression and activity. Cardiac transcriptomics revealed that the differentially expressed genes between isoproterenol-treated S330A KI and S330D KI mice were mainly involved in immune processes and inflammatory response. ß-arrestin-1 Ser330 phosphorylation inhibited isoproterenol-induced reactive oxygen species production and NLRP3 (NOD-like receptor protein 3) inflammasome activation in neonatal mouse cardiomyocytes. In S330D KI mice, the ß-AR-activated cAMP/PKA pathways were attenuated, leading to repressed inflammasome activation, reduced expression of proinflammatory cytokines, and mitigated macrophage infiltration. Compared with S330A KI mice, S330D KI mice showed diminished cardiac fibrosis and improved cardiac function upon isoproterenol exposure. However, the cardiac protection exerted by AMPK was abolished in S330A KI mice. CONCLUSIONS: AMPK phosphorylation of ß-arrestin-1 Ser330 potentiated PDE4 expression and activity, thereby inhibiting ß-AR/cAMP/PKA activation. Subsequently, ß-arrestin-1 Ser330 phosphorylation blocks ß-AR-induced cardiac inflammasome activation and remodeling.
Assuntos
Proteínas Quinases Ativadas por AMP , Isoproterenol , Miócitos Cardíacos , beta-Arrestina 1 , Animais , Fosforilação , beta-Arrestina 1/metabolismo , beta-Arrestina 1/genética , Camundongos , Proteínas Quinases Ativadas por AMP/metabolismo , Isoproterenol/toxicidade , Isoproterenol/farmacologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Camundongos Endogâmicos C57BL , Masculino , Receptores Adrenérgicos beta/metabolismo , Serina/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Agonistas Adrenérgicos beta/toxicidade , Células Cultivadas , Transdução de Sinais , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/genética , HumanosRESUMO
Atypical Chemokine Receptor 3 (ACKR3) belongs to the G protein-coupled receptor family but it does not signal through G proteins. The structural properties that govern the functional selectivity and the conformational dynamics of ACKR3 activation are poorly understood. Here, we combined hydrogen/deuterium exchange mass spectrometry, site-directed mutagenesis, and molecular dynamics simulations to examine the binding mode and mechanism of action of ACKR3 ligands of different efficacies. Our results show that activation or inhibition of ACKR3 is governed by intracellular conformational changes of helix 6, intracellular loop 2, and helix 7, while the DRY motif becomes protected during both processes. Moreover, we identified the binding sites and the allosteric modulation of ACKR3 upon ß-arrestin 1 binding. In summary, this study highlights the structure-function relationship of small ligands, the binding mode of ß-arrestin 1, the activation dynamics, and the atypical dynamic features in ACKR3 that may contribute to its inability to activate G proteins.
Assuntos
Simulação de Dinâmica Molecular , Ligação Proteica , Receptores CXCR , Humanos , Receptores CXCR/metabolismo , Receptores CXCR/genética , Sítios de Ligação , Conformação Proteica , beta-Arrestina 1/metabolismo , beta-Arrestina 1/genética , Ligantes , Células HEK293 , Mutagênese Sítio-Dirigida , Regulação Alostérica , Relação Estrutura-AtividadeRESUMO
OBJECTIVE: Intervertebral disc degeneration (IVDD) is the leading cause of lower back pain (LBP). ß-arrestin 1 (ARRB1) is a multifunctional protein that regulates numerous pathological processes. The aim of this study was to investigate the role of ARRB1 in IVDD. METHODS: The expression of ARRB1 in nucleus pulposus (NP) of rats with IVDD was assayed. Next, rat nucleus pulposus cells (NPCs) were infected with lentiviruses containing shArrb1 (LV-shArrb1) and overexpressing Arrb1 (LV-oeArrb1). The roles of Arrb1 in serum-deprived NPCs were investigated by measuring apoptosis, extracellular matrix degradation, and autophagic flux. For experiments in vivo, LV-oeArrb1 lentivirus was injected into the NP tissues of IVDD rats to evaluate the effects of Arrb1 overexpression on NP. RESULTS: In the NP tissues of IVDD rats, ARRB1 and cleaved caspase-3 expression increased, and the ratio of LC3II/LC3I protein expression was upregulated. Arrb1 knockdown aggravated extracellular matrix degradation, cellular apoptosis, and impairment of autophagic flux in rat NPCs under serum-deprived conditions, whereas Arrb1 overexpression significantly reversed these effects. ARRB1 interacted with Beclin 1, and Arrb1 knockdown suppressed the formation of the Beclin1-PIK3C3 core complex. The autophagy inhibitor 3-methyladenine (3-MA) offset the protective effects of Arrb1 overexpression in serum-deprived NPCs. Furthermore, Arrb1 overexpression inhibited apoptosis and extracellular matrix degradation, promoted autophagy in NP, and delayed the development of IVDD in rats. CONCLUSION: ARRB1 prevents extracellular matrix degradation and apoptosis of NPCs by upregulating autophagy and ameliorating IVDD progression, presenting an innovative strategy for the treatment of IVDD.
Assuntos
Apoptose , Autofagia , Matriz Extracelular , Degeneração do Disco Intervertebral , Núcleo Pulposo , beta-Arrestina 1 , Animais , Masculino , Ratos , Apoptose/genética , Autofagia/genética , beta-Arrestina 1/metabolismo , beta-Arrestina 1/genética , Células Cultivadas , Matriz Extracelular/metabolismo , Degeneração do Disco Intervertebral/metabolismo , Degeneração do Disco Intervertebral/genética , Degeneração do Disco Intervertebral/patologia , Núcleo Pulposo/metabolismo , Núcleo Pulposo/patologia , Ratos Sprague-DawleyRESUMO
Arrestins interact with phosphorylated G protein-coupled receptors (GPCRs) and regulate the homologous desensitization and internalization of GPCRs. The gate loop in arrestins is a critical region for both stabilization of the basal state and interaction with phosphorylated receptors. We investigated the roles of specific residues in the gate loop (K292, K294, and H295) using ß-arrestin-1 and phosphorylated C-tail peptide of vasopressin receptor type 2 (V2Rpp) as a model system. We measured the binding affinity of V2Rpp and analyzed conformational dynamics of ß-arrestin-1. Our results suggest that K294 plays a critical role in the interaction with V2Rpp without influencing the overall conformation of the V2Rpp-bound state. The residues K292 and H295 contribute to the stability of the polar core in the basal state and form a specific conformation of the finger loop in the V2Rpp-bound state.
Assuntos
Ligação Proteica , Receptores de Vasopressinas , beta-Arrestina 1 , Humanos , beta-Arrestina 1/metabolismo , beta-Arrestina 1/química , Sítios de Ligação , Modelos Moleculares , Simulação de Dinâmica Molecular , Fosforilação , Conformação Proteica , Receptores de Vasopressinas/metabolismo , Receptores de Vasopressinas/químicaRESUMO
Recruitment of fibroblasts to tumors and their activation into cancer-associated fibroblasts (CAFs) is a strategy used by tumor cells to direct extracellular matrix (ECM) remodeling, invasion, and metastasis, highlighting the need to investigate the molecular mechanisms driving CAF function. Endothelin-1 (ET-1) regulates the communication between cancer and stroma and facilitates the progression of serous ovarian cancer (SOC). By binding to Endothelin A (ETA) and B (ETB) receptors, ET-1 enables the recruitment of ß-arrestin1 (ß-arr1) and the formation of signaling complexes that coordinate tumor progression. However, how ET-1 receptors might "educate" human ovarian fibroblasts (HOFs) to produce altered ECM and promote metastasis remains to be elucidated. This study identifies ET-1 as a pivotal factor in the activation of CAFs capable of proteolytic ECM remodeling and the generation of heterotypic spheroids containing cancer cells with a propensity to metastasize. An autocrine/paracrine ET-1/ETA/BR/ß-arr1 loop enhances HOF proliferation, upregulates CAF marker expression, secretes pro-inflammatory cytokines, and increases collagen contractility, and cell motility. Furthermore, ET-1 facilitates ECM remodeling by promoting the lytic activity of invadosome and activation of integrin ß1. In addition, ET-1 signaling supports the formation of heterotypic HOF/SOC spheroids with enhanced ability to migrate through the mesothelial monolayer, and invade, representing metastatic units. The blockade of ETA/BR or ß-arr1 silencing prevents CAF activation, invadosome function, mesothelial clearance, and the invasive ability of heterotypic spheroids. In vivo, therapeutic inhibition of ETA/BR using bosentan (BOS) significantly reduces the metastatic potential of combined HOFs/SOC cells, associated with enhanced apoptotic effects on tumor cells and stromal components. These findings support a model in which ET-1/ß-arr1 reinforces tumor/stroma interaction through CAF activation and fosters the survival and metastatic properties of SOC cells, which could be counteracted by ETA/BR antagonists.
Assuntos
Fibroblastos Associados a Câncer , Neoplasias Ovarianas , Podossomos , beta-Arrestina 1 , Humanos , Feminino , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/genética , beta-Arrestina 1/metabolismo , beta-Arrestina 1/genética , Fibroblastos Associados a Câncer/metabolismo , Fibroblastos Associados a Câncer/patologia , Linhagem Celular Tumoral , Podossomos/metabolismo , Endotelina-1/metabolismo , Metástase Neoplásica , Receptor de Endotelina A/metabolismo , Transdução de Sinais , Matriz Extracelular/metabolismo , Movimento Celular , Proliferação de Células , Animais , Fibroblastos/metabolismo , Invasividade NeoplásicaRESUMO
The µ-opioid receptor (µOR) is an important target for pain management1 and molecular understanding of drug action on µOR will facilitate the development of better therapeutics. Here we show, using double electron-electron resonance and single-molecule fluorescence resonance energy transfer, how ligand-specific conformational changes of µOR translate into a broad range of intrinsic efficacies at the transducer level. We identify several conformations of the cytoplasmic face of the receptor that interconvert on different timescales, including a pre-activated conformation that is capable of G-protein binding, and a fully activated conformation that markedly reduces GDP affinity within the ternary complex. Interaction of ß-arrestin-1 with the µOR core binding site appears less specific and occurs with much lower affinity than binding of Gi.
Assuntos
Ligantes , Conformação Proteica , Receptores Opioides mu , Humanos , beta-Arrestina 1/química , beta-Arrestina 1/metabolismo , Sítios de Ligação , Transferência Ressonante de Energia de Fluorescência , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/química , Guanosina Difosfato/metabolismo , Guanosina Difosfato/química , Modelos Moleculares , Ligação Proteica , Receptores Opioides mu/metabolismo , Receptores Opioides mu/química , Imagem Individual de MoléculaRESUMO
The glucagon-like peptide 1 receptor (GLP-1R) is a validated clinical target for the treatment of type 2 diabetes and obesity. Unlike most G protein-coupled receptors (GPCRs), the GLP-1R undergoes an atypical mode of internalisation that does not require ß-arrestins. While differences in GLP-1R trafficking and ß-arrestin recruitment have been observed between clinically used GLP-1R agonists, the role of G protein-coupled receptor kinases (GRKs) in affecting these pathways has not been comprehensively assessed. In this study, we quantified the contribution of GRKs to agonist-mediated GLP-1R internalisation and ß-arrestin recruitment profiles using cells where endogenous ß-arrestins, or non-visual GRKs were knocked out using CRISPR/Cas9 genome editing. Our results confirm the previously established atypical ß-arrestin-independent mode of GLP-1R internalisation and revealed that GLP-1R internalisation is dependent on the expression of GRKs. Interestingly, agonist-mediated GLP-1R ß-arrestin 1 and ß-arrestin 2 recruitment were differentially affected by endogenous GRK knockout with ß-arrestin 1 recruitment more sensitive to GRK knockout than ß-arrestin 2 recruitment. Moreover, individual overexpression of GRK2, GRK3, GRK5 or GRK6 in a newly generated GRK2/3/4/5/6 HEK293 cells, rescued agonist-mediated ß-arrestin 1 recruitment and internalisation profiles to similar levels, suggesting that there is no specific GRK isoform that drives these pathways. This study advances mechanistic understanding of agonist-mediated GLP-1R internalisation and provides novel insights into how GRKs may fine-tune GLP-1R signalling.
Assuntos
Diabetes Mellitus Tipo 2 , Quinases de Receptores Acoplados a Proteína G , Humanos , Arrestinas/genética , Arrestinas/metabolismo , beta-Arrestina 1/metabolismo , beta-Arrestina 2/genética , beta-Arrestina 2/metabolismo , beta-Arrestinas/metabolismo , Quinases de Receptores Acoplados a Proteína G/genética , Quinases de Receptores Acoplados a Proteína G/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Células HEK293 , Fosforilação , Receptores Acoplados a Proteínas G/metabolismoRESUMO
The cannabinoid CB1 receptor (CB1) is a G protein-coupled receptor (GPCR) with widespread expression in the central nervous system. This canonically Gâºi/o-coupled receptor mediates the effects of Δ9-tetrahydrocannabinol (THC) and synthetic cannabinoid receptor agonists (SCRAs). Recreational use of SCRAs is associated with serious adverse health effects, making pharmacological research into these compounds a priority. Several studies have hypothesised that signalling bias may explain the different toxicological profiles between SCRAs and THC. Previous studies have focused on bias between G protein activation measured by cyclic adenosine monophosphate (cAMP) inhibition and ß-arrestin translocation. In contrast, the current study characterises bias between G⺠subtypes of the Gâºi/o family and ß-arrestins; this method facilitates a more accurate assessment of ligand bias by assessing signals that have not undergone major amplification. We have characterised G protein dissociation and translocation of ß-arrestin 1 and 2 using real-time BRET reporters. The responses produced by each SCRA across the G protein subtypes tested were consistent with the responses produced by the reference ligand AMB-FUBINACA. Ligand bias was probed by applying the operational analysis to determine biases within the Gâºi/o family, and between G protein subtypes and ß-arrestins. Overall, these results confirm SCRAs to be balanced, high-efficacy ligands compared to the low efficacy ligand THC, with only one SCRA, 4CN-MPP-BUT7IACA, demonstrating statistically significant bias in one pathway comparison (towards ß-arrestin 1 when compared with GâºoA/oB). This suggests that the adverse effects caused by SCRAs are due to high potency and efficacy at CB1, rather than biased agonism.
Assuntos
Agonistas de Receptores de Canabinoides , Canabinoides , Agonistas de Receptores de Canabinoides/farmacologia , Agonistas de Receptores de Canabinoides/metabolismo , beta-Arrestinas/metabolismo , Receptores de Canabinoides/metabolismo , beta-Arrestina 1/metabolismo , Ligantes , Proteínas de Ligação ao GTP/metabolismo , Canabinoides/farmacologia , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/metabolismoRESUMO
ß-arrestin-1 has been demonstrated to participate in the regulation of inflammatory reactions in several diseases. Thus, this study aimed to investigate the role of macrophage ß-arrestin-1 in the pathogenesis and progression of ulcerative colitis (UC). A myeloid ß-arrestin-1 conditional knockout mouse model was generated to explore the role of macrophage ß-arrestin-1. DSS was employed for the establishment of an ulcerative colitis mouse model, using TNF-α as an inflammatory stressor in vitro. The expression level of ß-arrestin-1 was detected via western blot and immunofluorescence assays, whilst disease severity was evaluated by clinical score and H&E staining in the DSS-induced colitis model. In the in vitro experiments, the levels of inflammatory cytokines were examined using real-time PCR. NF-κB activation was detected through the double luciferase reporter system, western blot, and electrophoretic mobility shift assay (EMSA). BAY11-7082 was used to inhibit NF-κB activation. Our results exposed that the level of ß-arrestin-1 was increased in monocytes/macrophages derived from DSS-induced colitis mice or under the TNF-α challenge. Moreover, conditionally knocking out the expression of myeloid ß-arrestin-1 alleviated disease severity, while knocking out the expression of ß-arrestin-1 decreased the levels of inflammatory cytokines. Additionally, NF-κB was identified as a central regulatory element of ß-arrestin-1 promoter, and using BAY11-7082 to inhibit NF-κB activation lowered the level of ß-arrestin-1 under TNF-α challenge. ß-arrestin-1 led to the activation of the NF-κB signaling pathway by enhancing binding to IκBα and IKK under the TNF-α challenge. Taken together, our findings demonstrated macrophage ß-arrestin-1 contributes to the deterioration of DSS-induced colitis through the interaction with NF-κB signaling, thus highlighting a novel target for the treatment of UC.
Assuntos
Colite Ulcerativa , Colite , Nitrilas , Sulfonas , Animais , Camundongos , NF-kappa B/metabolismo , Colite Ulcerativa/tratamento farmacológico , Fator de Necrose Tumoral alfa/metabolismo , beta-Arrestina 1/genética , beta-Arrestina 1/metabolismo , beta-Arrestina 1/uso terapêutico , Transdução de Sinais , Colite/induzido quimicamente , Colite/tratamento farmacológico , Citocinas/metabolismo , Macrófagos/metabolismo , Sulfato de Dextrana , Camundongos Endogâmicos C57BL , Modelos Animais de DoençasRESUMO
Glucagon-like peptide-1 receptor (GLP-1R) is a prime drug target for type 2 diabetes and obesity. The ligand initiated GLP-1R interaction with G protein has been well studied, but not with ß-arrestin 1/2. Therefore, bioluminescence resonance energy transfer (BRET), mutagenesis and an operational model were used to evaluate the roles of 85 extracellular surface residues on GLP-1R in ß-arrestin 1/2 recruitment triggered by three representative GLP-1R agonists (GLP-1, exendin-4 and oxyntomodulin). Residues selectively regulated ß-arrestin 1/2 recruitment for diverse ligands, and ß-arrestin isoforms were identified. Mutation of residues K130-S136, L142 and Y145 on the transmembrane helix 1 (TM1)-extracellular domain (ECD) linker decreased ß-arrestin 1 recruitment but increased ß-arrestin 2 recruitment. Other extracellular loop (ECL) mutations, including P137A, Q211A, D222A and M303A selectively affected ß-arrestin 1 recruitment while D215A, L217A, Q221A, S223A, Y289A, S301A, F381A and I382A involved more in ß-arrestin 2 recruitment for the ligands. Oxyntomodulin engaged more broadly with GLP-1R extracellular surface to drive ß-arrestin 1/2 recruitment than GLP-1 and exendin-4; I147, W214 and L218 involved in ß-arrestin 1 recruitment, while L141, D215, L218, D293 and F381 in ß-arrestin 2 recruitment for oxyntomodulin particularly. Additionally, the non-conserved residues on ß-arrestin 1/2 C-domains contributed to interaction with GLP-1R. Further proteomic profiling of GLP-1R stably expressed cell line upon ligand stimulation with or without ß-arrestin 1/2 overexpression demonstrated both commonly and biasedly regulated proteins and pathways associated with cognate ligands and ß-arrestins. Our study offers valuable information about ligand induced ß-arrestin recruitment mediated by GLP-1R and consequent intracellular signaling events.
Assuntos
Diabetes Mellitus Tipo 2 , Humanos , beta-Arrestina 1/metabolismo , Exenatida/farmacologia , beta-Arrestina 2/genética , beta-Arrestina 2/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Ligantes , Oxintomodulina/farmacologia , Proteômica , Peptídeo 1 Semelhante ao Glucagon/metabolismo , beta-Arrestinas/metabolismoRESUMO
ß-arrestins are a family of intracellular signaling proteins that play a key role in regulating the activity of G protein-coupled receptors. The angiotensin-II type 1 receptor is an important G protein-coupled receptor involved in the regulation of cardiovascular function and has been implicated in the progression of cardiovascular diseases. In addition to canonical G protein signaling, G protein-coupled receptors including the angiotensin-II type 1 receptor can signal via ß-arrestin. Dysregulation of ß-arrestin signaling has been linked to several cardiovascular diseases including hypertension, atherosclerosis, and heart failure. Understanding the role of ß-arrestins in these conditions is critical to provide new therapeutic targets for the treatment of cardiovascular disease. In this review, we will discuss the beneficial and maladaptive physiological outcomes of angiotensin-II type 1 receptor-dependent ß-arrestin activation in different cardiovascular diseases.
Assuntos
Doenças Cardiovasculares , Humanos , beta-Arrestinas , Arrestinas/metabolismo , Transdução de Sinais , Receptor Tipo 1 de Angiotensina/metabolismo , Angiotensinas/metabolismo , beta-Arrestina 2/genética , beta-Arrestina 2/metabolismo , beta-Arrestina 1/metabolismo , Angiotensina II/metabolismoRESUMO
T-2 toxin causes renal dysfunction with proteinuria and glomerular podocyte damage. This work explores the role of metabolic disorder/reprogramming-mediated epigenetic modification in the progression of T-2 toxin-stimulated podocyte injury. A metabolomics experiment is performed to assess metabolic responses to T-2 toxin infection in human podocytes. Roles of protein O-linked-N-acetylglucosaminylation (O-GlcNAcylation) in regulating T-2 toxin-stimulated podocyte injury in mouse and podocyte models are assessed. O-GlcNAc target proteins are recognized by mass spectrometry and co-immunoprecipitation experiments. Moreover, histone acetylation and autophagy levels are measured. T-2 toxin infection upregulates glucose transporter type 1 (GLUT1) expression and enhances hexosamine biosynthetic pathway in glomerular podocytes, resulting in a significant increase in ß-arrestin-1 O-GlcNAcylation. Decreasing ß-arrestin-1 or O-GlcNAc transferase (OGT) effectively prevents T-2 toxin-induced renal dysfunction and podocyte injury. Mechanistically, O-GlcNAcylation of ß-arrestin-1 stabilizes ß-arrestin-1 to activate the mammalian target of rapamycin (mTOR) pathway as well as to inhibit autophagy during podocyte injury by promoting H4K16 acetylation. To sum up, OGT-mediated ß-arrestin-1 O-GlcNAcylation is a vital regulator in the development of T-2 toxin-stimulated podocyte injury via activating the mTOR pathway to suppress autophagy. Targeting ß-arrestin-1 or OGT can be a potential therapy for T-2 toxin infection-associated glomerular injury, especially podocyte injury.
Assuntos
Nefropatias , Podócitos , Toxina T-2 , Camundongos , Humanos , Animais , Acetilação , Histonas/metabolismo , Podócitos/metabolismo , beta-Arrestina 1/metabolismo , Toxina T-2/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Nefropatias/metabolismo , Mamíferos/metabolismoRESUMO
G protein-coupled receptors (GPCRs) are leading druggable targets for several medicines, but many GPCRs are still untapped for their therapeutic potential due to poor understanding of specific signaling properties. The complement C3a receptor 1 (C3aR1) has been extensively studied for its physiological role in C3a-mediated anaphylaxis/inflammation, and in TLQP-21-mediated lipolysis, but direct evidence for the functional relevance of the C3a and TLQP-21 ligands and signal transduction mechanisms are still limited. In addition, C3aR1 G protein coupling specificity is still unclear, and whether endogenous ligands, or drug-like compounds, show ligand-mediated biased agonism is unknown. Here, we demonstrate that C3aR1 couples preferentially to Gi/o/z proteins and can recruit ß-arrestins to cause internalization. Furthermore, we showed that in comparison to C3a63-77, TLQP-21 exhibits a preference toward Gi/o-mediated signaling compared to ß-arrestin recruitment and internalization. We also show that the purported antagonist SB290157 is a very potent C3aR1 agonist, where antagonism of ligand-stimulated C3aR1 calcium flux is caused by potent ß-arrestin-mediated internalization. Finally, ligand-mediated signaling bias impacted cell function as demonstrated by the regulation of calcium influx, lipolysis in adipocytes, phagocytosis in microglia, and degranulation in mast cells. Overall, we characterize C3aR1 as a Gi/o/z-coupled receptor and demonstrate the functional relevance of ligand-mediated signaling bias in key cellular models. Due to C3aR1 and its endogenous ligands being implicated in inflammatory and metabolic diseases, these results are of relevance toward future C3aR1 drug discovery.
Assuntos
Cálcio , Complemento C3a , beta-Arrestina 1/metabolismo , beta-Arrestinas/metabolismo , Cálcio/metabolismo , Complemento C3a/metabolismo , Ligantes , Receptores Acoplados a Proteínas G/metabolismo , Humanos , Animais , Camundongos , Linhagem CelularRESUMO
It has been documented that increased sympathetic activity contributes to the development of cardiovascular diseases, such as hypertension. We previously reported that ß-arrestin-1, a multifunctional cytoskeletal protein, was downregulated in the rostral ventrolateral medulla (RVLM) of the spontaneously hypertensive rat (SHR), and its overexpression elicited an inhibitory effect on sympathetic activity in hypertension. microRNA (miR)-22-3p has been reported to be associated with the pathological progress of hypertension. The purpose of this study was to determine the role of miR-22-3p in ß-arrestin-1-mediated central cardiovascular regulation in hypertension. It was observed that miR-22-3p was upregulated in the RVLM of SHRs compared with normotensive Wistar-Kyoto (WKY) rats, and it was subsequently confirmed to target the ß-arrestin-1 gene using a dual-luciferase reporter assay. miR-22-3p was downregulated in the RVLM using adeno-associated virus with 'tough decoys', which caused a significant increase of ß-arrestin-1 expression and decrease of noradrenaline and blood pressure (BP) in SHRs. However, upregulation of miR-22-3p using lentivirus in the RVLM of WKY rats significantly increased BP. In in vitro PC12 cells, enhanced oxidative stress activity induced by angiotensin II was counteracted by pretreatment with miR-22-3p inhibitor, and this effect could be abolished by ß-arrestin-1 gene knockdown. Furthermore, microglia exhaustion significantly diminished miR-22-3p expression, and enhanced ß-arrestin-1 expression in the RVLM of SHRs. Activation of BV2 cells in vitro evoked a significant increase of miR-22-3p expression, and this BV2 cell culture medium was also able to facilitate miR-22-3p expression in PC12 cells. Collectively, our findings support a critical role for microglia-derived miR-22-3p in inhibiting ß-arrestin-1 in the RVLM, which is involved in central cardiovascular regulation in hypertension. KEY POINTS: Impairment of ß-arrestin-1 function in the rostral ventrolateral medulla (RVLM) has been reported to be associated with the development of sympathetic overactivity in hypertension. However, little is known about the potential mechanisms of ß-arrestin-1 dysfunction in hypertension. miR-22-3p is implicated in multiple biological processes, but the role of miR-22-3p in central regulation of cardiovascular activity in hypertension remains unknown. We predicted that miR-22-3p could directly bind to the ß-arrestin-1 gene (Arrb1), and this hypothesis was confirmed by using a dual-luciferase reporter assay. Inhibition of ß-arrestin-1 by miR-22-3p was further verified in both in vivo and in vitro experiments. Furthermore, our results suggested miR-22-3p as a risk factor for oxidative stress in the RVLM, thus contributing to sympatho-excitation and hypertension. Our present study provides evidence that microglia-derived miR-22-3p may underlie the pathogenesis and progression of neuronal hypertension by inhibiting ß-arrestin-1 in the RVLM.
Assuntos
Hipertensão , MicroRNAs , Animais , Ratos , beta-Arrestina 1/genética , beta-Arrestina 1/metabolismo , Pressão Sanguínea/fisiologia , Luciferases/metabolismo , Bulbo/fisiologia , MicroRNAs/genética , MicroRNAs/metabolismo , Ratos Endogâmicos SHR , Ratos Endogâmicos WKYRESUMO
GPR101 is an orphan G protein-coupled receptor that promotes growth hormone secretion in the pituitary. The microduplication of the GPR101 gene has been linked with the X-linked acrogigantism, or X-LAG, syndrome. This disease is characterized by excessive growth hormone secretion and abnormal rapid growth beginning early in life. Mechanistically, GPR101 induces growth hormone secretion through constitutive activation of multiple heterotrimeric G proteins. However, the full scope of GPR101 signaling remains largely elusive. Herein, we investigated the association of GPR101 to multiple transducers and uncovered an important basal interaction with Arrestin 2 (ß-arrestin 1) and Arrestin 3 (ß-arrestin 2). By using a GPR101 mutant lacking the C-terminus and cell lines with an Arrestin 2/3 null background, we show that the arrestin association leads to constitutive clathrin- and dynamin-mediated GPR101 internalization. To further highlight GPR101 intracellular fate, we assessed the colocalization of GPR101 with Rab protein markers. Internalized GPR101 was mainly colocalized with the early endosome markers, Rab5 and EEA-1, and to a lesser degree with the late endosome marker Rab7. However, GPR101 was not colocalized with the recycling endosome marker Rab11. These findings show that the basal arrestin recruitment by GPR101 C-terminal tail drives the receptor constitutive clathrin-mediated internalization. Intracellularly, GPR101 concentrates in the endosomal compartment and is degraded through the lysosomal pathway. In conclusion, we uncovered a constitutive intracellular trafficking of GPR101 that potentially represents an important layer of regulation of its signaling and function.
Assuntos
Arrestinas , Receptores Acoplados a Proteínas G , beta-Arrestina 1/metabolismo , beta-Arrestinas/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Arrestinas/genética , Arrestinas/metabolismo , beta-Arrestina 2/metabolismo , Hormônio do Crescimento , Clatrina/metabolismo , EndocitoseRESUMO
Cannabis activates the cannabinoid receptor 1 (CB1), which elicits analgesic and emotion regulation benefits, along with adverse effects, via Gi and ß-arrestin signaling pathways. However, the lack of understanding of the mechanism of ß-arrestin-1 (ßarr1) coupling and signaling bias has hindered drug development targeting CB1. Here, we present the high-resolution cryo-electron microscopy structure of CB1-ßarr1 complex bound to the synthetic cannabinoid MDMB-Fubinaca (FUB), revealing notable differences in the transducer pocket and ligand-binding site compared with the Gi protein complex. ßarr1 occupies a wider transducer pocket promoting substantial outward movement of the TM6 and distinctive twin toggle switch rearrangements, whereas FUB adopts a different pose, inserting more deeply than the Gi-coupled state, suggesting the allosteric correlation between the orthosteric binding pocket and the partner protein site. Taken together, our findings unravel the molecular mechanism of signaling bias toward CB1, facilitating the development of CB1 agonists.
Assuntos
Arrestina , Receptor CB1 de Canabinoide , Transdução de Sinais , Arrestina/metabolismo , beta-Arrestina 1/metabolismo , beta-Arrestinas/metabolismo , Microscopia Crioeletrônica , Receptor CB1 de Canabinoide/metabolismo , Humanos , Animais , Linhagem CelularRESUMO
Cannabinoid CB2 receptor (CB2R) is a class A G protein-coupled receptor (GPCR) involved in a broad spectrum of physiological processes and pathological conditions. For that reason, targeting CB2R might provide therapeutic opportunities in neurodegenerative disorders, neuropathic pain, inflammatory diseases, and cancer. The main components from Cannabis sativa, such as Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD), have been therapeutically exploited and synthetically-derived analogs have been generated. One example is cannabidiol-dimethylheptyl (CBD-DMH), which exhibits anti-inflammatory effects. Nevertheless, its pharmacological mechanism of action is not yet fully understood and is hypothesized for multiple targets, including CB2R. The aim of this study was to further investigate the molecular pharmacology of CBD-DMH on CB2R while CBD was taken along as control. These compounds were screened in equilibrium and kinetic radioligand binding studies and various functional assays, including G protein activation, inhibition of cAMP production and ß-arrestin-2 recruitment. In dissociation studies, CBD-DMH allosterically modulated the radioligand binding. Furthermore, CBD-DMH negatively modulated the G protein activation of reference agonists CP55,940, AEA and 2-AG, but not the agonist-induced ß-arrestin-2 recruitment. Nevertheless, CBD-DMH also displayed competitive binding to CB2R and partial agonism on G protein activation, inhibition of cAMP production and ß-arrestin-2 recruitment. CBD did not exhibit such allosteric behavior and only very weakly bound CB2R without activation. This study shows a dual binding mode of CBD-DMH, but not CBD, to CB2R with the suggestion of two different binding sites. Altogether, it encourages further research into this dual mechanism which might provide a new class of molecules targeting CB2R.
Assuntos
Canabidiol , Canabidiol/farmacologia , Receptores de Canabinoides/metabolismo , beta-Arrestina 1/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Receptor CB2 de Canabinoide/metabolismo , Dronabinol , Receptor CB1 de Canabinoide/metabolismo , Agonistas de Receptores de CanabinoidesRESUMO
G protein-coupled receptor (GPCR) signaling and trafficking are regulated by multiple mechanisms, including posttranslational modifications such as ubiquitination by E3 ubiquitin ligases. E3 ligases have been linked to agonist-stimulated ubiquitination of GPCRs via simultaneous binding to ßarrestins. In addition, ßarrestins have been suggested to assist E3 ligases for ubiquitination of key effector molecules, yet mechanistic insight is lacking. Here, we developed an in vitro reconstituted system and show that ßarrestin1 (ßarr1) serves as an adaptor between the effector protein signal-transducing adaptor molecule 1 (STAM1) and the E3 ligase atrophin-interacting protein 4. Via mass spectrometry, we identified seven lysine residues within STAM1 that are ubiquitinated and several types of ubiquitin linkages. We provide evidence that ßarr1 facilitates the formation of linear polyubiquitin chains at lysine residue 136 on STAM1. This lysine residue is important for stabilizing the ßarr1:STAM1 interaction in cells following GPCR activation. Our study identifies atrophin-interacting protein 4 as only the second E3 ligase known to conjugate linear polyubiquitin chains and a possible role for linear ubiquitin chains in GPCR signaling and trafficking.
Assuntos
Poliubiquitina , Ubiquitina-Proteína Ligases , beta-Arrestina 1 , Lisina/metabolismo , Poliubiquitina/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação , beta-Arrestina 1/metabolismoRESUMO
ß-Arrestins (ßarrs) are functionally versatile proteins that play critical roles in the G-protein-coupled receptor (GPCR) signaling pathways. While it is well established that the phosphorylated receptor tail plays a central role in ßarr activation, emerging evidence highlights the contribution from membrane lipids. However, detailed molecular mechanisms of ßarr activation by different binding partners remain elusive. In this work, we present a comprehensive study of the structural changes in critical regions of ßarr1 during activation using 19F NMR spectroscopy. We show that phosphopeptides derived from different classes of GPCRs display different ßarr1 activation abilities, whereas binding of the membrane phosphoinositide PIP2 stabilizes a distinct partially activated conformational state. Our results further unveil a sparsely-populated activation intermediate as well as complex cross-talks between different binding partners, implying a highly multifaceted conformational energy landscape of ßarr1 that can be intricately modulated during signaling.