1
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Kelly LM, Rutter JC, Lin KH, Ling F, Duchmann M, Latour E, Arang N, Pasquer H, Ho Nhat D, Charles J, Killarney ST, Ang HX, Namor F, Culeux C, Lombard B, Loew D, Swaney DL, Krogan NJ, Brunel L, Carretero É, Verdié P, Amblard M, Fodil S, Huynh T, Sebert M, Adès L, Raffoux E, Fenouille N, Itzykson R, Lobry C, Benajiba L, Forget A, Martin AR, Wood KC, Puissant A. Targeting a lineage-specific PI3Kɣ-Akt signaling module in acute myeloid leukemia using a heterobifunctional degrader molecule. NATURE CANCER 2024; 5:1082-1101. [PMID: 38816660 DOI: 10.1038/s43018-024-00782-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 05/13/2024] [Indexed: 06/01/2024]
Abstract
Dose-limiting toxicity poses a major limitation to the clinical utility of targeted cancer therapies, often arising from target engagement in nonmalignant tissues. This obstacle can be minimized by targeting cancer dependencies driven by proteins with tissue-restricted and/or tumor-restricted expression. In line with another recent report, we show here that, in acute myeloid leukemia (AML), suppression of the myeloid-restricted PIK3CG/p110γ-PIK3R5/p101 axis inhibits protein kinase B/Akt signaling and compromises AML cell fitness. Furthermore, silencing the genes encoding PIK3CG/p110γ or PIK3R5/p101 sensitizes AML cells to established AML therapies. Importantly, we find that existing small-molecule inhibitors against PIK3CG are insufficient to achieve a sustained long-term antileukemic effect. To address this concern, we developed a proteolysis-targeting chimera (PROTAC) heterobifunctional molecule that specifically degrades PIK3CG and potently suppresses AML progression alone and in combination with venetoclax in human AML cell lines, primary samples from patients with AML and syngeneic mouse models.
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Affiliation(s)
- Lois M Kelly
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Justine C Rutter
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| | - Kevin H Lin
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| | - Frank Ling
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Matthieu Duchmann
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Emmanuelle Latour
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Nadia Arang
- Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Hélène Pasquer
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Duong Ho Nhat
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Juliette Charles
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Shane T Killarney
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| | - Hazel X Ang
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA
| | - Federica Namor
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Cécile Culeux
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Bérangère Lombard
- Curie Institute, Mass Spectrometry and Proteomics Facility, PSL Research University, Paris, France
| | - Damarys Loew
- Curie Institute, Mass Spectrometry and Proteomics Facility, PSL Research University, Paris, France
| | - Danielle L Swaney
- Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
- Gladstone Institutes, San Francisco, California, USA
| | - Nevan J Krogan
- Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
- Gladstone Institutes, San Francisco, California, USA
| | - Luc Brunel
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Élodie Carretero
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Pascal Verdié
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Muriel Amblard
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Sofiane Fodil
- Department of Hematology and Immunology, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Tony Huynh
- Department of Hematology and Immunology, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Marie Sebert
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
- Department of Hematology and Immunology, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Lionel Adès
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
- Department of Hematology and Immunology, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Emmanuel Raffoux
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
- Department of Hematology and Immunology, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Nina Fenouille
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Raphaël Itzykson
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
- Department of Hematology and Immunology, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Camille Lobry
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
| | - Lina Benajiba
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France
- Clinical Investigation Center, Saint-Louis Hospital, AP-HP, Paris Cité University, Paris, France
| | - Antoine Forget
- Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Anthony R Martin
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Kris C Wood
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC, USA.
| | - Alexandre Puissant
- INSERM UMR 944, IRSL, Saint-Louis Hospital, Paris Cité University, Paris, France.
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Lau HCH, Zhang X, Ji F, Lin Y, Liang W, Li Q, Chen D, Fong W, Kang X, Liu W, Chu ESH, Ng QWY, Yu J. Lactobacillus acidophilus suppresses non-alcoholic fatty liver disease-associated hepatocellular carcinoma through producing valeric acid. EBioMedicine 2024; 100:104952. [PMID: 38176203 PMCID: PMC10801313 DOI: 10.1016/j.ebiom.2023.104952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/05/2023] [Accepted: 12/19/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND Gut probiotic depletion is associated with non-alcoholic fatty liver disease-associated hepatocellular carcinoma (NAFLD-HCC). Here, we investigated the prophylactic potential of Lactobacillus acidophilus against NAFLD-HCC. METHODS NAFLD-HCC conventional and germ-free mice were established by diethylnitrosamine (DEN) injection with feeding of high-fat high-cholesterol (HFHC) or choline-deficient high-fat (CDHF) diet. Orthotopic NAFLD-HCC allografts were established by intrahepatic injection of murine HCC cells with HFHC feeding. Metabolomic profiling was performed using liquid chromatography-mass spectrometry. Biological functions of L. acidophilus conditional medium (L.a CM) and metabolites were determined in NAFLD-HCC human cells and mouse organoids. FINDINGS L. acidophilus supplementation suppressed NAFLD-HCC formation in HFHC-fed DEN-treated mice. This was confirmed in orthotopic allografts and germ-free tumourigenesis mice. L.a CM inhibited the growth of NAFLD-HCC human cells and mouse organoids. The protective function of L. acidophilus was attributed to its non-protein small molecules. By metabolomic profiling, valeric acid was the top enriched metabolite in L.a CM and its upregulation was verified in liver and portal vein of L. acidophilus-treated mice. The protective function of valeric acid was demonstrated in NAFLD-HCC human cells and mouse organoids. Valeric acid significantly suppressed NAFLD-HCC formation in HFHC-fed DEN-treated mice, accompanied by improved intestinal barrier integrity. This was confirmed in another NAFLD-HCC mouse model induced by CDHF diet and DEN. Mechanistically, valeric acid bound to hepatocytic surface receptor GPR41/43 to inhibit Rho-GTPase pathway, thereby ablating NAFLD-HCC. INTERPRETATION L. acidophilus exhibits anti-tumourigenic effect in mice by secreting valeric acid. Probiotic supplementation is a potential prophylactic of NAFLD-HCC. FUNDING Shown in Acknowledgments.
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Affiliation(s)
- Harry Cheuk-Hay Lau
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiang Zhang
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Fenfen Ji
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Yufeng Lin
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Wei Liang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Qing Li
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Danyu Chen
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Winnie Fong
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Xing Kang
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Weixin Liu
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Eagle Siu-Hong Chu
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Queena Wing-Yin Ng
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Jun Yu
- State Key Laboratory of Digestive Disease, Department of Medicine and Therapeutics, Institute of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China.
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Harvey BJ. Molecular mechanisms of dexamethasone actions in COVID-19: Ion channels and airway surface liquid dynamics. Steroids 2024; 202:109348. [PMID: 38049079 DOI: 10.1016/j.steroids.2023.109348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
The COVID-19 pandemic has been a global health crisis of unprecedented magnitude. In the battle against the SARS-CoV-2 coronavirus, dexamethasone, a widely used corticosteroid with potent anti-inflammatory properties, has emerged as a promising therapy in the fight against severe COVID-19. Dexamethasone is a synthetic glucocorticoid that exerts its therapeutic effects by suppressing the immune system and reducing inflammation. In the context of COVID-19, the severe form of the disease is often characterized by a hyperactive immune response, known as a cytokine storm. Dexamethasone anti-inflammatory properties make it a potent tool in modulating this exaggerated immune response. Lung inflammation may lead to excessive fluid accumulation in the airways which can reduce gas exchange and mucociliary clearance. Pulmonary oedema and flooding of the airways are hallmarks of severe COVID-19 lung disease. The volume of airway surface liquid is determined by a delicate balance of salt and water secretion and absorption across the airway epithelium. In addition to its anti-inflammatory actions, dexamethasone modulates the activity of ion channels which regulate electrolyte and water transport across the airway epithelium. The observations of dexamethasone activation of sodium ion absorption via ENaC Na+ channels and inhibition of chloride ion secretion via CFTR Cl- channels to decrease airway surface liquid volume indicate a novel therapeutic action of the glucocorticoid to reverse airway flooding. This brief review delves into the early non-genomic and late genomic signaling mechanisms of dexamethasone regulation of ion channels and airway surface liquid dynamics, shedding light on the molecular mechanisms underpinning the action of the glucocorticoid in managing COVID-19.
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Affiliation(s)
- Brian J Harvey
- Faculty of Medicine, Royal College of Surgeons in Ireland, RCSI University of Medicine and Health Sciences, Dublin 2, Ireland; Centro de Estudios Cientificos, Valdivia, Chile.
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Wu JR, Zohra R, Duong NKT, Yeh CH, Lu CA, Wu SJ. A plant protein farnesylation system in prokaryotic cells reveals Arabidopsis AtJ3 produced and farnesylated in E. coli maintains its function of protecting proteins from heat inactivation. PLANT METHODS 2023; 19:113. [PMID: 37884965 PMCID: PMC10604809 DOI: 10.1186/s13007-023-01087-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023]
Abstract
BACKGROUND Protein farnesylation involves the addition of a 15-carbon polyunsaturated farnesyl group to proteins whose C-terminus ends with a CaaX motif. This post-translational protein modification is catalyzed by a heterodimeric protein, i.e., farnesyltransferase (PFT), which is composed of an α and a β subunit. Protein farnesylation in plants is of great interest because of its important roles in the regulation of plant development, responses to environmental stresses, and defense against pathogens. The methods traditionally used to verify whether a protein is farnesylated often require a specific antibody and involve isotope labeling, a tedious and time-consuming process that poses hazardous risks. RESULTS Since protein farnesylation does not occur in prokaryotic cells, we co-expressed a known PFT substrate (i.e., AtJ3) and both the α and β subunits of Arabidopsis PFT in E. coli in this study. Farnesylation of AtJ3 was detected using electrophoretic mobility using SDS-PAGE and confirmed using mass spectrometry. AtJ3 is a member of the heat shock protein 40 family and interacts with Arabidopsis HSP70 to protect plant proteins from heat-stress-induced denaturation. A luciferase-based protein denaturation assay demonstrated that farnesylated AtJ3 isolated from E. coli maintained this ability. Interestingly, farnesylated AtJ3 interacted with E. coli HSP70 as well and enhanced the thermotolerance of E. coli. Meanwhile, AtFP3, another known PFT substrate, was farnesylated when co-expressed with AtPFTα and AtPFTβ in E. coli. Moreover, using the same strategy to co-express rice PFT α and β subunit and a potential PFT target, it was confirmed that OsDjA4, a homolog of AtJ3, was farnesylated. CONCLUSION We developed a protein farnesylation system for E. coli and demonstrated its applicability and practicality in producing functional farnesylated proteins from both mono- and dicotyledonous plants.
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Affiliation(s)
- Jia-Rong Wu
- Department of Life Sciences, National Central University, 300 Jhong-Da Road, Jhong-Li District, Taoyuan, 32001, Taiwan
| | - Rida Zohra
- Department of Life Sciences, National Central University, 300 Jhong-Da Road, Jhong-Li District, Taoyuan, 32001, Taiwan
| | - Ngoc Kieu Thi Duong
- Department of Life Sciences, National Central University, 300 Jhong-Da Road, Jhong-Li District, Taoyuan, 32001, Taiwan
| | - Ching-Hui Yeh
- Department of Life Sciences, National Central University, 300 Jhong-Da Road, Jhong-Li District, Taoyuan, 32001, Taiwan
| | - Chung-An Lu
- Department of Life Sciences, National Central University, 300 Jhong-Da Road, Jhong-Li District, Taoyuan, 32001, Taiwan.
| | - Shaw-Jye Wu
- Department of Life Sciences, National Central University, 300 Jhong-Da Road, Jhong-Li District, Taoyuan, 32001, Taiwan.
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Hanson J. [G proteins: privileged transducers of 7-transmembrane spanning receptors]. Biol Aujourdhui 2022; 215:95-106. [PMID: 35275054 DOI: 10.1051/jbio/2021011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Indexed: 06/14/2023]
Abstract
G protein-coupled receptors or GPCR are the most abundant membrane receptors in our genome with around 800 members. They play an essential role in most physiological and pathophysiological phenomena. In addition, they constitute 30% of the targets of currently marketed drugs and remain an important reservoir for new innovative therapies. Their main effectors are heterotrimeric G proteins. These are composed of 3 subunits, α, β and γ, which, upon coupling with a GPCR, dissociate into Gα and Gβγ to activate numerous signaling pathways. This article describes some of the recent advances in understanding the function and role of heterotrimeric G proteins. After a short introduction to GPCRs, the history of the discovery of G proteins is briefly described. Then, the fundamental mechanisms of activation, signaling and regulation of G proteins are reviewed. New paradigms concerning intracellular signaling, specific recognition of G proteins by GPCRs as well as biased signaling are also discussed.
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Affiliation(s)
- Julien Hanson
- Laboratoire de Pharmacologie Moléculaire, GIGA-Molecular Biology of Diseases, Université de Liège, CHU, B34, Tour GIGA (+4), Avenue de l'Hôpital 11, B-4000 Liège, Belgique
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6
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Moo EV, Harpsøe K, Hauser AS, Masuho I, Bräuner-Osborne H, Gloriam DE, Martemyanov KA. Ligand-directed bias of G protein signaling at the dopamine D 2 receptor. Cell Chem Biol 2022; 29:226-238.e4. [PMID: 34302750 PMCID: PMC8770702 DOI: 10.1016/j.chembiol.2021.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/21/2021] [Accepted: 07/02/2021] [Indexed: 01/11/2023]
Abstract
G-protein-coupled receptors (GPCRs) represent the largest family of drug targets. Upon activation, GPCRs signal primarily via a diverse set of heterotrimeric G proteins. Most GPCRs can couple to several different G protein subtypes. However, how drugs act at GPCRs contributing to the selectivity of G protein recognition is poorly understood. Here, we examined the G protein selectivity profile of the dopamine D2 receptor (D2), a GPCR targeted by antipsychotic drugs. We show that D2 discriminates between six individual members of the Gi/o family, and its profile of functional selectivity is remarkably different across its ligands, which all engaged D2 with a distinct G protein coupling pattern. Using structural modeling, receptor mutagenesis, and pharmacological evaluation, we identified residues in the D2 binding pocket that shape these ligand-directed biases. We further provide pharmacogenomic evidence that natural variants in D2 differentially affect its G protein biases in response to different ligands.
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Affiliation(s)
- Ee Von Moo
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA,Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Kasper Harpsøe
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Alexander S Hauser
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - David E. Gloriam
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Kirill A. Martemyanov
- Department of Neuroscience, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
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Servant NB, Williams ME, Brust PF, Tang H, Wong MS, Chen Q, Lebl-Rinnova M, Adamski-Werner SL, Tachdjian C, Servant G. A Dynamic Mass Redistribution Assay for the Human Sweet Taste Receptor Uncovers G-Protein Dependent Biased Ligands. Front Pharmacol 2022; 13:832529. [PMID: 35250580 PMCID: PMC8893300 DOI: 10.3389/fphar.2022.832529] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/24/2022] [Indexed: 12/26/2022] Open
Abstract
The sweet taste receptor is rather unique, recognizing a diverse repertoire of natural or synthetic ligands, with a surprisingly large structural diversity, and with potencies stretching over more than six orders of magnitude. Yet, it is not clear if different cell-based assays can faithfully report the relative potencies and efficacies of these molecules. Indeed, up to now, sweet taste receptor agonists have been almost exclusively characterized using cell-based assays developed with overexpressed and promiscuous G proteins. This non-physiological coupling has allowed the quantification of receptor activity via phospholipase C activation and calcium mobilization measurements in heterologous cells on a FLIPR system, for example. Here, we developed a novel assay for the human sweet taste receptor where endogenous G proteins and signaling pathways are recruited by the activated receptor. The effects of several sweet taste receptor agonists and other types of modulators were recorded by measuring changes in dynamic mass redistribution (DMR) using an Epic® reader. Potency and efficacy values obtained in the DMR assay were compared to those results obtained with the classical FLIPR assay. Results demonstrate that for some ligands, the two assay systems provide similar information. However, a clear bias for the FLIPR assay was observed for one third of the agonists evaluated, suggesting that the use of non-physiological coupling may influence the potency and efficacy of sweet taste receptor ligands. Replacing the promiscuous G protein with a chimeric G protein containing the C-terminal tail 25 residues of the physiologically relevant G protein subunit Gαgustducin reduced or abrogated bias.
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Cxcl10 chemokine induces migration of ING4-deficient breast cancer cells via a novel crosstalk mechanism between the Cxcr3 and Egfr receptors. Mol Cell Biol 2021; 42:e0038221. [PMID: 34871062 DOI: 10.1128/mcb.00382-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chemokine Cxcl10 has been associated with poor prognosis in breast cancer, but the mechanism is not well understood. Our previous study have shown that CXCL10 was repressed by the ING4 tumor suppressor, suggesting a potential inverse functional relationship. We thus investigated a role for Cxcl10 in the context of ING4 deficiencies in breast cancer. We first analyzed public gene expression datasets and found that patients with CXCL10-high/ING4-low expressing tumors had significantly reduced disease-free survival in breast cancer. In vitro, Cxcl10 induced migration of ING4-deleted breast cancer cells, but not of ING4-intact cells. Using inhibitors, we found that Cxcl10-induced migration of ING4-deleted cells required Cxcr3, Egfr, and the Gβγ subunits downstream of Cxcr3, but not Gαi. Immunofluorescent imaging showed that Cxcl10 induced early transient colocalization between Cxcr3 and Egfr in both ING4-intact and ING4-deleted cells, which recurred only in ING4-deleted cells. A peptide agent that binds to the internal juxtamembrane domain of Egfr inhibited Cxcr3/Egfr colocalization and cell migration. Taken together, these results presented a novel mechanism of Cxcl10 that elicits migration of ING4-deleted cells, in part by inducing a physical or proximal association between Cxcr3 and Egfr and signaling downstream via Gβγ. These results further indicated that ING4 plays a critical role in the regulation of Cxcl10 signaling that enables breast cancer progression.
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Naseer S, Hussain W, Khan YD, Rasool N. NPalmitoylDeep-PseAAC: A Predictor of N-Palmitoylation Sites in Proteins Using Deep Representations of Proteins and PseAAC via Modified 5-Steps Rule. Curr Bioinform 2021. [DOI: 10.2174/1574893615999200605142828] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Among all the major Post-translational modification, lipid modifications
possess special significance due to their widespread functional importance in eukaryotic cells. There
exist multiple types of lipid modifications and Palmitoylation, among them, is one of the broader
types of modification, having three different types. The N-Palmitoylation is carried out by
attachment of palmitic acid to an N-terminal cysteine. Due to the association of N-Palmitoylation
with various biological functions and diseases such as Alzheimer’s and other neurodegenerative
diseases, its identification is very important.
Objective:
The in vitro, ex vivo and in vivo identification of Palmitoylation is laborious, time-taking
and costly. There is a dire need for an efficient and accurate computational model to help researchers
and biologists identify these sites, in an easy manner. Herein, we propose a novel prediction model
for the identification of N-Palmitoylation sites in proteins.
Method:
The proposed prediction model is developed by combining the Chou’s Pseudo Amino
Acid Composition (PseAAC) with deep neural networks. We used well-known deep neural
networks (DNNs) for both the tasks of learning a feature representation of peptide sequences and
developing a prediction model to perform classification.
Results:
Among different DNNs, Gated Recurrent Unit (GRU) based RNN model showed the
highest scores in terms of accuracy, and all other computed measures, and outperforms all the
previously reported predictors.
Conclusion:
The proposed GRU based RNN model can help to identify N-Palmitoylation in a very
efficient and accurate manner which can help scientists understand the mechanism of this
modification in proteins.
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Affiliation(s)
- Sheraz Naseer
- Department of Computer Science, School of Systems and Technology, University of Management and Technology, P.O. Box 10033, C-II, Johar Town, Lahore 54770, Pakistan
| | - Waqar Hussain
- National Center of Artificial Intelligence, Punjab University College of Information Technology, University of the Punjab, Lahore, Pakistan
| | - Yaser Daanial Khan
- Department of Computer Science, School of Systems and Technology, University of Management and Technology, P.O. Box 10033, C-II, Johar Town, Lahore 54770, Pakistan
| | - Nouman Rasool
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
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McLean JS, Bor B, Kerns KA, Liu Q, To TT, Solden L, Hendrickson EL, Wrighton K, Shi W, He X. Acquisition and Adaptation of Ultra-small Parasitic Reduced Genome Bacteria to Mammalian Hosts. Cell Rep 2021; 32:107939. [PMID: 32698001 PMCID: PMC7427843 DOI: 10.1016/j.celrep.2020.107939] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/20/2020] [Accepted: 06/30/2020] [Indexed: 12/31/2022] Open
Abstract
The first cultivated representative of the enigmatic phylum Saccharibacteria (formerly TM7) was isolated from humans and revealed an ultra-small cell size (200-300 nm), a reduced genome with limited biosynthetic capabilities, and a unique parasitic lifestyle. TM7x was the only cultivated member of the candidate phyla radiation (CPR), estimated to encompass 26% of the domain Bacteria. Here we report on divergent genomes from major lineages across the Saccharibacteria phylum in humans and mammals, as well as from ancient dental calculus. These lineages are present at high prevalence within hosts. Direct imaging reveals that all groups are ultra-small in size, likely feeding off commensal bacteria. Analyses suggest that multiple acquisition events in the past led to the current wide diversity, with convergent evolution of key functions allowing Saccharibacteria from the environment to adapt to mammals. Ultra-small, parasitic CPR bacteria represent a relatively unexplored paradigm of prokaryotic interactions within mammalian microbiomes.
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Affiliation(s)
- Jeffrey S McLean
- Department of Periodontics, University of Washington, Seattle, WA 98195, USA; Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
| | - Batbileg Bor
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142, USA; Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Kristopher A Kerns
- Department of Periodontics, University of Washington, Seattle, WA 98195, USA
| | - Quanhui Liu
- Department of Periodontics, University of Washington, Seattle, WA 98195, USA
| | - Thao T To
- Department of Periodontics, University of Washington, Seattle, WA 98195, USA
| | - Lindsey Solden
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Erik L Hendrickson
- Department of Periodontics, University of Washington, Seattle, WA 98195, USA
| | - Kelly Wrighton
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Wenyuan Shi
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142, USA
| | - Xuesong He
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142, USA; Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA 02115, USA
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11
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Ma Q, Cao Z, Li H, Wang W, Tian Y, Yan L, Liao Y, Chen X, Chen Y, Shi Y, Tang S, Zhou N. Two naturally occurring mutations of human GPR103 define distinct G protein selection bias. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119046. [PMID: 33872671 DOI: 10.1016/j.bbamcr.2021.119046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/18/2022]
Abstract
The neuropeptide 26RFa plays important roles in the regulation of many physiological functions. 26RFa has been recognized as an endogenous ligand for receptor GPR103. In the present study, we demonstrate that GPR103 dually couples to Gαq and Gαi/o proteins. However, two naturally occurring missense mutations were identified from a young male patient. In the first, Y68H, induction of Ca2+ mobilization was noted without detection of ERK1/2 activation. In the second, R371W, the potential to activate ERK1/2 signaling was retained but with failure to evoke Ca2+ mobilization. Further analysis provides evidence that Gαq, L-type Ca2+ channel and PKCβI and βII are involved in the Y68H-mediated signaling pathway, whereas Gαi/o, Gβγ, and PKCζ are implicated in the R371W-induced signaling. Our results demonstrate that two point mutations, Y68H and R371W, affect the equilibrium between the different receptor conformations, leading to alteration of G protein-coupling preferences. Importantly, these findings provide a foundation for future elucidation of GPCR-mediated biased signaling and the physiological implications of their bias.
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Affiliation(s)
- Qiang Ma
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China; Department of Neurobiology, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Brain Science and Brian Medicine, MOE Frontier Center of Brain Science and Brain-machine Integration, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Zheng Cao
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Huanzheng Li
- Wenzhou Key Laboratory of Birth Defects, Wenzhou Central Hospital, Wenzhou, Zhejiang 325000, China
| | - Weiwei Wang
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yanan Tian
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lili Yan
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yuan Liao
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiangnan Chen
- Wenzhou Key Laboratory of Birth Defects, Wenzhou Central Hospital, Wenzhou, Zhejiang 325000, China
| | - Yu Chen
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ying Shi
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Shaohua Tang
- Wenzhou Key Laboratory of Birth Defects, Wenzhou Central Hospital, Wenzhou, Zhejiang 325000, China; School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 32500, China
| | - Naiming Zhou
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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12
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Coevolution underlies GPCR-G protein selectivity and functionality. Sci Rep 2021; 11:7858. [PMID: 33846507 PMCID: PMC8041822 DOI: 10.1038/s41598-021-87251-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/25/2021] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) regulate diverse physiological events, which makes them as the major targets for many approved drugs. G proteins are downstream molecules that receive signals from GPCRs and trigger cell responses. The GPCR-G protein selectivity mechanism on how they properly and timely interact is still unclear. Here, we analyzed model GPCRs (i.e. HTR, DAR) and Gα proteins with a coevolutionary tool, statistical coupling analysis. The results suggested that 5-hydroxytryptamine receptors and dopamine receptors have common conserved and coevolved residues. The Gα protein also have conserved and coevolved residues. These coevolved residues were implicated in the molecular functions of the analyzed proteins. We also found specific coevolving pairs related to the selectivity between GPCR and G protein were identified. We propose that these results would contribute to better understandings of not only the functional residues of GPCRs and Gα proteins but also GPCR-G protein selectivity mechanisms.
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13
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SPrenylC-PseAAC: A sequence-based model developed via Chou's 5-steps rule and general PseAAC for identifying S-prenylation sites in proteins. J Theor Biol 2019; 468:1-11. [DOI: 10.1016/j.jtbi.2019.02.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/07/2019] [Accepted: 02/11/2019] [Indexed: 11/22/2022]
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14
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SPalmitoylC-PseAAC: A sequence-based model developed via Chou's 5-steps rule and general PseAAC for identifying S-palmitoylation sites in proteins. Anal Biochem 2019; 568:14-23. [DOI: 10.1016/j.ab.2018.12.019] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/19/2018] [Accepted: 12/22/2018] [Indexed: 02/06/2023]
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15
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Vural A, Nabar NR, Hwang IY, Sohn S, Park C, Karlsson MCI, Blumer JB, Kehrl JH. Gα i2 Signaling Regulates Inflammasome Priming and Cytokine Production by Biasing Macrophage Phenotype Determination. THE JOURNAL OF IMMUNOLOGY 2019; 202:1510-1520. [PMID: 30683698 DOI: 10.4049/jimmunol.1801145] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/19/2018] [Indexed: 12/14/2022]
Abstract
Macrophages exist as innate immune subsets that exhibit phenotypic heterogeneity and functional plasticity. Their phenotypes are dictated by inputs from the tissue microenvironment. G-protein-coupled receptors are essential in transducing signals from the microenvironment, and heterotrimeric Gα signaling links these receptors to downstream effectors. Several Gαi-coupled G-protein-coupled receptors have been implicated in macrophage polarization. In this study, we use genetically modified mice to investigate the role of Gαi2 on inflammasome activity and macrophage polarization. We report that Gαi2 in murine bone marrow-derived macrophages (BMDMs) regulates IL-1β release after activation of the NLRP3, AIM2, and NLRC4 inflammasomes. We show this regulation stems from the biased polarity of Gαi2 deficient (Gnai2 -/-) and RGS-insensitive Gαi2 (Gnai2 G184S/G184S) BMDMs. We determined that although Gnai2 G184S/G184S BMDMs (excess Gαi2 signaling) have a tendency toward classically activated proinflammatory (M1) phenotype, Gnai2-/- BMDMs (Gαi2 deficient) are biased toward alternatively activated anti-inflammatory (M2) phenotype. Finally, we find that Gαi2-deficient macrophages have increased Akt activation and IFN-β production but defects in ERK1/2 and STAT3 activation after LPS stimulation. Gαi2-deficient macrophages also exhibit increased STAT6 activation after IL-4 stimulation. In summary, our data indicates that excess Gαi2 signaling promotes an M1 macrophage phenotype, whereas Gαi2 signaling deficiency promotes an M2 phenotype. Understanding Gαi2-mediated effects on macrophage polarization may bring to light insights regarding disease pathogenesis and the reprogramming of macrophages for the development of novel therapeutics.
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Affiliation(s)
- Ali Vural
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Neel R Nabar
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892; .,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden; and
| | - Il-Young Hwang
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Silke Sohn
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden; and
| | - Chung Park
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Mikael C I Karlsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden; and
| | - Joe B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29425
| | - John H Kehrl
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
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16
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Krishna BA, Miller WE, O'Connor CM. US28: HCMV's Swiss Army Knife. Viruses 2018; 10:E445. [PMID: 30127279 PMCID: PMC6116241 DOI: 10.3390/v10080445] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/08/2018] [Accepted: 08/17/2018] [Indexed: 12/13/2022] Open
Abstract
US28 is one of four G protein coupled receptors (GPCRs) encoded by human cytomegalovirus (HCMV). The US28 protein (pUS28) is a potent signaling molecule that alters a variety of cellular pathways that ultimately alter the host cell environment. This viral GPCR is expressed not only in the context of lytic replication but also during viral latency, highlighting its multifunctional properties. pUS28 is a functional GPCR, and its manipulation of multiple signaling pathways likely impacts HCMV pathogenesis. Herein, we will discuss the impact of pUS28 on both lytic and latent infection, pUS28-mediated signaling and its downstream consequences, and the influence this viral GPCR may have on disease states, including cardiovascular disease and cancer. We will also discuss the potential for and progress towards exploiting pUS28 as a novel therapeutic to combat HCMV.
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Affiliation(s)
- Benjamin A Krishna
- Genomic Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | - William E Miller
- Department of Molecular Genetics, Biochemistry, & Microbiology, University of Cincinnati, Cincinnati, OH 45267, USA.
| | - Christine M O'Connor
- Genomic Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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17
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Fenske RJ, Kimple ME. Targeting dysfunctional beta-cell signaling for the potential treatment of type 1 diabetes mellitus. Exp Biol Med (Maywood) 2018; 243:586-591. [PMID: 29504478 DOI: 10.1177/1535370218761662] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Since its discovery and purification by Frederick Banting in 1921, exogenous insulin has remained almost the sole therapy for type 1 diabetes mellitus. While insulin alleviates the primary dysfunction of the disease, many other aspects of the pathophysiology of type 1 diabetes mellitus are unaffected. Research aimed towards the discovery of novel type 1 diabetes mellitus therapeutics targeting different cell signaling pathways is gaining momentum. The focus of these efforts has been almost entirely on the impact of immunomodulatory drugs, particularly those that have already received FDA-approval for other autoimmune diseases. However, these drugs can often have severe side effects, while also putting already immunocompromised individuals at an increased risk for other infections. Potential therapeutic targets in the insulin-producing beta-cell have been largely ignored by the type 1 diabetes mellitus field, save the glucagon-like peptide 1 receptor. While there is preliminary evidence to support the clinical exploration of glucagon-like peptide 1 receptor-based drugs as type 1 diabetes mellitus adjuvant therapeutics, there is a vast space for other putative therapeutic targets to be explored. The alpha subunit of the heterotrimeric Gz protein (Gαz) has been shown to promote beta-cell inflammation, dysfunction, death, and failure to replicate in the context of diabetes in a number of mouse models. Genetic loss of Gαz or inhibition of the Gαz signaling pathway through dietary interventions is protective against the development of insulitis and hyperglycemia. The multifaceted effects of Gαz in regards to beta-cell health in the context of diabetes make it an ideal therapeutic target for further study. It is our belief that a low-risk, effective therapy for type 1 diabetes mellitus will involve a multidimensional approach targeting a number of regulatory systems, not the least of which is the insulin-producing beta-cell. Impact statement The expanding investigation of beta-cell therapeutic targets for the treatment and prevention of type 1 diabetes mellitus is fundamentally relevant and timely. This review summarizes the overall scope of research into novel type 1 diabetes mellitus therapeutics, highlighting weaknesses or caveats in current clinical trials as well as describing potential new targets to pursue. More specifically, signaling proteins that act as modulators of beta-cell function, survival, and replication, as well as immune infiltration may need to be targeted to develop the most efficient pharmaceutical interventions for type 1 diabetes mellitus. One such beta-cell signaling pathway, mediated by the alpha subunit of the heterotrimeric Gz protein (Gαz), is discussed in more detail. The work described here will be critical in moving the field forward as it emphasizes the central role of the beta-cell in type 1 diabetes mellitus disease pathology.
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Affiliation(s)
- Rachel J Fenske
- 1 Interdisciplinary Graduate Program in Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.,2 Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA.,3 Research Service, William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Michelle E Kimple
- 1 Interdisciplinary Graduate Program in Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.,2 Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA.,3 Research Service, William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA.,4 Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53705, USA
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18
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Ballister ER, Rodgers J, Martial F, Lucas RJ. A live cell assay of GPCR coupling allows identification of optogenetic tools for controlling Go and Gi signaling. BMC Biol 2018; 16:10. [PMID: 29338718 PMCID: PMC5771134 DOI: 10.1186/s12915-017-0475-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/18/2017] [Indexed: 11/10/2022] Open
Abstract
Background Animal opsins are light-sensitive G-protein-coupled receptors (GPCRs) that enable optogenetic control over the major heterotrimeric G-protein signaling pathways in animal cells. As such, opsins have potential applications in both biomedical research and therapy. Selecting the opsin with the best balance of activity and selectivity for a given application requires knowing their ability to couple to a full range of relevant Gα subunits. We present the GsX assay, a set of tools based on chimeric Gs subunits that transduce coupling of opsins to diverse G proteins into increases in cAMP levels, measured with a real-time reporter in living cells. We use this assay to compare coupling to Gi/o/t across a panel of natural and chimeric opsins selected for potential application in gene therapy for retinal degeneration. Results Of the opsins tested, wild-type human rod opsin had the highest activity for chimeric Gs proxies for Gi and Gt (Gsi and Gst) and was matched in Go proxy (Gso) activity only by a human rod opsin/scallop opsin chimera. Rod opsin drove roughly equivalent responses via Gsi, Gso, and Gst, while cone opsins showed much lower activities with Gso than Gsi or Gst, and a human rod opsin/amphioxus opsin chimera demonstrated higher activity with Gso than with Gsi or Gst. We failed to detect activity for opsin chimeras bearing three intracellular fragments of mGluR6, and observed unexpectedly complex response profiles for scallop and amphioxus opsins thought to be specialized for Go. Conclusions These results identify rod opsin as the most potent non-selective Gi/o/t-coupled opsin, long-wave sensitive cone opsin as the best for selectively activating Gi/t over Go, and a rod opsin/amphioxus opsin chimera as the best choice for selectively activating Go over Gi/t. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0475-2) contains supplementary material, which is available to authorized users.
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19
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Carboneau BA, Breyer RM, Gannon M. Regulation of pancreatic β-cell function and mass dynamics by prostaglandin signaling. J Cell Commun Signal 2017; 11:105-116. [PMID: 28132118 DOI: 10.1007/s12079-017-0377-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/16/2017] [Indexed: 01/09/2023] Open
Abstract
Prostaglandins (PGs) are signaling lipids derived from arachidonic acid (AA), which is metabolized by cyclooxygenase (COX)-1 or 2 and class-specific synthases to generate PGD2, PGE2, PGF2α, PGI2 (prostacyclin), and thromboxane A2. PGs signal through G-protein coupled receptors (GPCRs) and are important modulators of an array of physiological functions, including systemic inflammation and insulin secretion from pancreatic islets. The role of PGs in β-cell function has been an active area of interest, beginning in the 1970s. Early studies demonstrated that PGE2 inhibits glucose-stimulated insulin secretion (GSIS), although more recent studies have questioned this inhibitory action of PGE2. The PGE2 receptor EP3 and one of the G-proteins that couples to EP3, GαZ, have been identified as negative regulators of β-cell proliferation and survival. Conversely, PGI2 and its receptor, IP, play a positive role in the β-cell by enhancing GSIS and preserving β-cell mass in response to the β-cell toxin streptozotocin (STZ). In comparison to PGE2 and PGI2, little is known about the function of the remaining PGs within islets. In this review, we discuss the roles of PGs, particularly PGE2 and PGI2, PG receptors, and downstream signaling events that alter β-cell function and regulation of β-cell mass.
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Affiliation(s)
- Bethany A Carboneau
- Department of Veterans Affairs, Tennessee Valley Health Authority, Nashville, TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Richard M Breyer
- Department of Veterans Affairs, Tennessee Valley Health Authority, Nashville, TN, USA.,Department of Medicine, Division of Nephrology, Vanderbilt University Medical Center, Nashville, USA
| | - Maureen Gannon
- Department of Veterans Affairs, Tennessee Valley Health Authority, Nashville, TN, USA. .,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA. .,Program in Developmental Biology, Vanderbilt University, Nashville, TN, USA. .,Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA. .,Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA.
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20
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Black JB, Premont RT, Daaka Y. Feedback regulation of G protein-coupled receptor signaling by GRKs and arrestins. Semin Cell Dev Biol 2016; 50:95-104. [PMID: 26773211 PMCID: PMC4779377 DOI: 10.1016/j.semcdb.2015.12.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/19/2015] [Indexed: 12/16/2022]
Abstract
GPCRs are ubiquitous in mammalian cells and present intricate mechanisms for cellular signaling and communication. Mechanistically, GPCR signaling was identified to occur vectorially through heterotrimeric G proteins that are negatively regulated by GRK and arrestin effectors. Emerging evidence highlights additional roles for GRK and Arrestin partners, and establishes the existence of interconnected feedback pathways that collectively define GPCR signaling. GPCRs influence cellular dynamics and can mediate pathologic development, such as cancer and cardiovascular remolding. Hence, a better understanding of their overall signal regulation is of great translational interest and research continues to exploit the pharmacologic potential for modulating their activity.
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Affiliation(s)
- Joseph B Black
- Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL 32610, United States
| | - Richard T Premont
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, United States
| | - Yehia Daaka
- Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL 32610, United States.
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21
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Choudhary S, Goetjen A, Estus T, Jacome-Galarza CE, Aguila HL, Lorenzo J, Pilbeam C. Serum Amyloid A3 Secreted by Preosteoclasts Inhibits Parathyroid Hormone-stimulated cAMP Signaling in Murine Osteoblasts. J Biol Chem 2015; 291:3882-94. [PMID: 26703472 DOI: 10.1074/jbc.m115.686576] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 12/25/2022] Open
Abstract
Continuous parathyroid hormone (PTH) blocks its own osteogenic actions in marrow stromal cell cultures by inducing Cox2 and receptor activator of nuclear factor κB ligand (RANKL) in the osteoblastic lineage cells, which then cause the hematopoietic lineage cells to secrete an inhibitor of PTH-stimulated osteoblast differentiation. To identify this inhibitor, we used bone marrow macrophages (BMMs) and primary osteoblasts (POBs) from WT and Cox2 knock-out (KO) mice. Conditioned medium (CM) from RANKL-treated WT, but not KO, BMMs blocked PTH-stimulated cAMP production in POBs. Inhibition was reversed by pertussis toxin (PTX), which blocks Gαi/o activation. Saa3 was the most highly differentially expressed gene in a microarray comparison of RANKL-treated WT versus Cox2 KO BMMs, and RANKL induced Saa3 protein secretion only from WT BMMs. CM from RANKL-stimulated BMMs with Saa3 knockdown did not inhibit PTH-stimulated responses in POBs. SAA added to POBs inhibited PTH-stimulated cAMP responses, which was reversed by PTX. Selective agonists and antagonists of formyl peptide receptor 2 (Fpr2) suggested that Fpr2 mediated the inhibitory actions of Saa3 on osteoblasts. In BMMs committed to become osteoclasts by RANKL treatment, Saa3 expression peaked prior to appearance of multinucleated cells. Flow sorting of WT marrow revealed that Saa3 was secreted only from the RANKL-stimulated B220(-) CD3(-)CD11b(-/low) CD115(+) preosteoclast population. We conclude that Saa3 secretion from preosteoclasts, induced by RANKL in a Cox2-dependent manner, inhibits PTH-stimulated cAMP signaling and osteoblast differentiation via Gαi/o signaling. The induction of Saa3 by PTH may explain the suppression of bone formation when PTH is applied continuously and may be a new therapeutic target for osteoporosis.
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Affiliation(s)
- Shilpa Choudhary
- New England Musculoskeletal Institute, University of Connecticut Health, Farmington, Connecticut 06030 From the Departments of Medicine and
| | - Alexandra Goetjen
- New England Musculoskeletal Institute, University of Connecticut Health, Farmington, Connecticut 06030
| | - Thomas Estus
- New England Musculoskeletal Institute, University of Connecticut Health, Farmington, Connecticut 06030
| | | | | | - Joseph Lorenzo
- New England Musculoskeletal Institute, University of Connecticut Health, Farmington, Connecticut 06030 From the Departments of Medicine and
| | - Carol Pilbeam
- New England Musculoskeletal Institute, University of Connecticut Health, Farmington, Connecticut 06030 From the Departments of Medicine and
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22
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Apelin-13 enhances arcuate POMC neuron activity via inhibiting M-current. PLoS One 2015; 10:e0119457. [PMID: 25782002 PMCID: PMC4363569 DOI: 10.1371/journal.pone.0119457] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 01/25/2015] [Indexed: 12/03/2022] Open
Abstract
The hypothalamus is a key element of the neural circuits that control energy homeostasis. Specific neuronal populations within the hypothalamus are sensitive to a variety of homeostatic indicators such as circulating nutrient levels and hormones that signal circulating glucose and body fat content. Central injection of apelin secreted by adipose tissues regulates feeding and glucose homeostasis. However, the precise neuronal populations and cellular mechanisms involved in these physiological processes remain unclear. Here we examine the electrophysiological impact of apelin-13 on proopiomelanocortin (POMC) neuron activity. Approximately half of POMC neurons examined respond to apelin-13. Apelin-13 causes a dose-dependent depolarization. This effect is abolished by the apelin (APJ) receptor antagonist. POMC neurons from animals pre-treated with pertussis toxin still respond to apelin, whereas the Gβγ signaling inhibitor gallein blocks apelin-mediated depolarization. In addition, the effect of apelin is inhibited by the phospholipase C and protein kinase inhibitors. Furthermore, single-cell qPCR analysis shows that POMC neurons express the APJ receptor, PLC-β isoforms, and KCNQ subunits (2, 3 and 5) which contribute to M-type current. Apelin-13 inhibits M-current that is blocked by the KCNQ channel inhibitor. Therefore, our present data indicate that apelin activates APJ receptors, and the resultant dissociation of the Gαq heterotrimer triggers a Gβγ-dependent activation of PLC-β signaling that inhibits M-current.
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23
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Dascal N, Kahanovitch U. The Roles of Gβγ and Gα in Gating and Regulation of GIRK Channels. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 123:27-85. [DOI: 10.1016/bs.irn.2015.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Yu L, Sun Y, Cheng L, Jin Z, Yang Y, Zhai M, Pei H, Wang X, Zhang H, Meng Q, Zhang Y, Yu S, Duan W. Melatonin receptor-mediated protection against myocardial ischemia/reperfusion injury: role of SIRT1. J Pineal Res 2014; 57:228-38. [PMID: 25052362 DOI: 10.1111/jpi.12161] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/18/2014] [Indexed: 11/28/2022]
Abstract
Melatonin confers cardioprotective effect against myocardial ischemia/reperfusion (MI/R) injury by reducing oxidative stress. Activation of silent information regulator 1 (SIRT1) signaling also reduces MI/R injury. We hypothesize that melatonin may protect against MI/R injury by activating SIRT1 signaling. This study investigated the protective effect of melatonin treatment on MI/R heart and elucidated its potential mechanisms. Rats were exposed to melatonin treatment in the presence or the absence of the melatonin receptor antagonist luzindole or SIRT1 inhibitor EX527 and then subjected to MI/R operation. Melatonin conferred a cardioprotective effect by improving postischemic cardiac function, decreasing infarct size, reducing apoptotic index, diminishing serum creatine kinase and lactate dehydrogenase release, upregulating SIRT1, Bcl-2 expression and downregulating Bax, caspase-3 and cleaved caspase-3 expression. Melatonin treatment also resulted in reduced myocardium superoxide generation, gp91(phox) expression, malondialdehyde level, and increased myocardium superoxide dismutase (SOD) level, which indicate that the MI/R-induced oxidative stress was significantly attenuated. However, these protective effects were blocked by EX527 or luzindole, indicating that SIRT1 signaling and melatonin receptor may be specifically involved in these effects. In summary, our results demonstrate that melatonin treatment attenuates MI/R injury by reducing oxidative stress damage via activation of SIRT1 signaling in a receptor-dependent manner.
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Affiliation(s)
- Liming Yu
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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Gupta AK, Giaglis S, Hasler P, Hahn S. Efficient neutrophil extracellular trap induction requires mobilization of both intracellular and extracellular calcium pools and is modulated by cyclosporine A. PLoS One 2014; 9:e97088. [PMID: 24819773 PMCID: PMC4018253 DOI: 10.1371/journal.pone.0097088] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 04/14/2014] [Indexed: 12/21/2022] Open
Abstract
Excessive or aberrant generation of neutrophil extracellular traps (NETs) has recently become implicated in the underlying aetiology of a number of human pathologies including preeclampsia, systemic lupus erythromatosus, rheumatoid arthritis, auto-antibody induced small vessel vasculitis, coagulopathies such as deep vein thrombosis or pulmonary complications. These results imply that effective pharmacological therapeutic strategies will need to be developed to counter overt NETosis in these and other inflammatory disorders. As calcium flux is implicated in the generation of reactive oxygen species and histone citrullination, two key events in NETosis, we analysed the roles of both extra- and intracellular calcium pools and their modulation by pharmacological agents in the NETotic process in detail. Interleukin-8 (IL-8) was used as a physiological stimulus of NETosis. Our data demonstrate that efficient induction of NETosis requires mobilisation of both extracellular and intracellular calcium pools. Since modulation of the calcineurin pathway by cyclosporine A has been described in neutrophils, we investigated its influence on NETosis. Our data indicate that IL-8 induced NETosis is reduced by ascomycin and cyclosporine A, antagonists of the calcineurin pathway, but not following treatment with rapamycin, which utilizes the mTOR pathway. The action of the G protein coupled receptor phospholipase C pathway appears to be essential for the induction of NETs by IL-8, as NETosis was diminished by treatment with either pertussis toxin, a G-protein inhibitor, the phospholipase C inhibitor, U73122, or staurosporine, an inhibitor of protein kinase C. The data regarding the calcineurin antagonists, ascomycin and cyclosporine A, open the possibility to therapeutically supress or modulate NETosis. They also provide new insight into the mechanism whereby such immune suppressive drugs render transplant patients susceptible to opportunistic fungal infections.
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Affiliation(s)
- Anurag Kumar Gupta
- Laboratory for Prenatal Medicine, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Stavros Giaglis
- Laboratory for Prenatal Medicine, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Department of Rheumatology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Paul Hasler
- Department of Rheumatology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Sinuhe Hahn
- Laboratory for Prenatal Medicine, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- * E-mail:
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Chen L, He X, Zhang Y, Chen X, Lai X, Shao J, Shi Y, Zhou N. Melatonin receptor type 1 signals to extracellular signal-regulated kinase 1 and 2 via Gi and Gs dually coupled pathways in HEK-293 cells. Biochemistry 2014; 53:2827-39. [PMID: 24724723 DOI: 10.1021/bi500092e] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The pineal gland hormone melatonin exerts its regulatory roles in a variety of physiological and pathological responses through two G protein-coupled receptors, melatonin receptor type 1 (MT1) and melatonin receptor type 2 (MT2), which have been recognized as promising targets in the treatment of a number of human diseases and disorders. The MT1 receptor was identified nearly 20 years ago; however, the molecular mechanisms by which MT1-mediated signaling affects physiology remain to be further elucidated. In this study, using HEK293 cells stably expressing the human MT1 receptor, melatonin induced a concentration-dependent activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2). The melatonin-mediated phosphorylation of ERK1/2 at later time points (≥5 min) was strongly suppressed by pretreatment with pertussis toxin, but only a slight, if any, inhibition of ERK1/2 activation at early time points (≤2 min) was detected. Further experiments demonstrated that the Gβγ subunit, phosphoinositide 3-kinase, and calcium-insensitive protein kinase C were involved in the MT1-mediated activation of ERK1/2 at later time points (≥5 min). Moreover, results derived from cAMP assays combined with a MT1 mutant indicated that the human MT1 receptor could also couple to Gs protein, stimulating intracellular cAMP formation, and that the MT1-induced activation of ERK1/2 at early time points (≤2 min) was mediated by the Gs/cAMP/PKA cascade. Our findings may provide new insights into the pharmacological effects and physiological functions modulated by the MT1-mediated activation of ERK1/2.
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Affiliation(s)
- Linjie Chen
- Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou, Zhejiang 310058, China
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Neuman JC, Kimple ME. The EP3 Receptor: Exploring a New Target for Type 2 Diabetes Therapeutics. JOURNAL OF ENDOCRINOLOGY, DIABETES & OBESITY 2013; 1:1002. [PMID: 26322320 PMCID: PMC4551503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Joshua C. Neuman
- Department of Nutritional Sciences, University of Wisconsin-Madison, Wisconsin, USA
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Sundström L, Greasley PJ, Engberg S, Wallander M, Ryberg E. Succinate receptor GPR91, a Gα(i) coupled receptor that increases intracellular calcium concentrations through PLCβ. FEBS Lett 2013; 587:2399-404. [PMID: 23770096 DOI: 10.1016/j.febslet.2013.05.067] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/30/2013] [Accepted: 05/30/2013] [Indexed: 11/15/2022]
Abstract
Succinate has been reported as the endogenous ligand for GPR91. In this study, succinate was confirmed to activate GPR91 resulting in both 3'-5'-cyclic adenosine monophosphate (cAMP) inhibition and inositol phosphate formation in a pertussis toxin (PTX)-sensitive manner. GPR91 agonist-mediated effects detected using dynamic mass redistribution (DMR) were inhibited with PTX, edelfosine and U73122 demonstrating the importance of not only the Gαi pathway but also PLCβ. These results show that GPR91 when expressed in HEK293s cells couples exclusively through the Gαi pathway and acts through Gαi not only to inhibit cAMP production but also to increase intracellular Ca(2+) in an inositol phosphate dependent mechanism via PLCβ activation.
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Fang C, Avis I, Bianco C, Held N, Morris J, Ylaya K, Hewitt SM, Aplin AC, Nicosia RF, Fung LA, Lewis JD, Stetler-Stevenson WG, Salomon DS, Cuttitta F. SCNH2 is a novel apelinergic family member acting as a potent mitogenic and chemotactic factor for both endothelial and epithelial cells. ACTA ACUST UNITED AC 2013; 3:37-51. [PMID: 23956953 DOI: 10.4236/ojcd.2013.32009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The gut hormone apelin is a major therapeutic focus for several diseases involving inflammation and aberrant cell growth. We investigated whether apelin-36 contained alternative bioactive peptides associated with normal physiology or disease. Amino acid sequence analysis of apelin-36 identified an amidation motif consistent with the formation of a secondary bioactive peptide (SCNH2). SCNH2 is proven to be mitogenic and chemotactic in normal/malignant cells and augments angiogenesis via a PTX-resistant/CT-X-sensitive G protein-coupled receptor (GPCR). Notably, SCNH2 is substantially more potent and sensitive than apelin-13 and vascular endothelial growth factor-A. Endogenous SCNH2 is highly expressed in human tumors and placenta and in mouse embryonic tissues. Our findings demonstrate that SCNH2 is a new apelinergic member with critical pluripotent roles in angiogenesis related diseases and embryogenesis via a non-APJ GPCR.
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Affiliation(s)
- Changge Fang
- Angiogenesis Core Facility, Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, USA
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Zhou Q, Li G, Deng XY, He XB, Chen LJ, Wu C, Shi Y, Wu KP, Mei LJ, Lu JX, Zhou NM. Activated human hydroxy-carboxylic acid receptor-3 signals to MAP kinase cascades via the PLC-dependent PKC and MMP-mediated EGFR pathways. Br J Pharmacol 2012; 166:1756-73. [PMID: 22289163 DOI: 10.1111/j.1476-5381.2012.01875.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE 3-Hydroxy-octanoate, recently identified as a ligand for, the orphan GPCR, HCA(3), is of particular interest given its ability to treat lipid disorders and atherosclerosis. Here we demonstrate the pathway of HCA(3)-mediated activation of ERK1/2. EXPERIMENTAL APPROACH Using CHO-K1 cells stably expressing HCA(3) receptors and A431 cells, a human epidermoid cell line with high levels of endogenous expression of functional HCA(3) receptors, HCA(3)-mediated activation of ERK1/2 was measured by Western blot. KEY RESULTS HCA(3)-mediated activation of ERK1/2 was rapid, peaking at 5 min, and was Pertussis toxin sensitive. Our data, obtained by time course analyses in combination with different kinase inhibitors, demonstrated that on agonist stimulation, HCA(3) receptors evoked ERK1/2 activation via two distinct pathways, the PLC/PKC pathway at early time points (≤ 2 min) and the MMP/ epidermal growth factor receptor (EGFR) transactivation pathway with a maximum response at 5 min. Furthermore, our present results also indicated that the βγ-subunits of the G(i) protein play a critical role in HCA(3)-activated ERK1/2 phosphorylation, whereas β-arrestins and Src were not required for ERK1/2 activation. CONCLUSIONS AND IMPLICATIONS We have described the molecular mechanisms underlying the coupling of human HCA(3) receptors to the ERK1/2 MAP kinase pathway in CHO-K1 and A431 cells, which implicate the G(i) protein-initiated, PLC/PKC -and platelet-derived growth factor receptor/EGFR transactivation-dependent pathways. These observations may provide new insights into the pharmacological effects and the physiological functions modulated by the HCA(3)-mediated activation of ERK1/2.
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Affiliation(s)
- Q Zhou
- Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine and Life Science, Wenzhou Medical College, Wenzhou, Zhejiang, China
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Abstract
Hedgehog (Hh) proteins regulate the development of a wide range of metazoan embryonic and adult structures, and disruption of Hh signaling pathways results in various human diseases. Here, we provide a comprehensive review of the signaling pathways regulated by Hh, consolidating data from a diverse array of organisms in a variety of scientific disciplines. Similar to the elucidation of many other signaling pathways, our knowledge of Hh signaling developed in a sequential manner centered on its earliest discoveries. Thus, our knowledge of Hh signaling has for the most part focused on elucidating the mechanism by which Hh regulates the Gli family of transcription factors, the so-called "canonical" Hh signaling pathway. However, in the past few years, numerous studies have shown that Hh proteins can also signal through Gli-independent mechanisms collectively referred to as "noncanonical" signaling pathways. Noncanonical Hh signaling is itself subdivided into two distinct signaling modules: (i) those not requiring Smoothened (Smo) and (ii) those downstream of Smo that do not require Gli transcription factors. Thus, Hh signaling is now proposed to occur through a variety of distinct context-dependent signaling modules that have the ability to crosstalk with one another to form an interacting, dynamic Hh signaling network.
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Affiliation(s)
- David J Robbins
- Molecular Oncology Program, Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
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Arcand J, Robitaille G, Koenig M, Senécal JL, Raymond Y. The autoantigen DNA topoisomerase I interacts with chemokine receptor 7 and exerts cytokine-like effects on dermal fibroblasts. ACTA ACUST UNITED AC 2012; 64:826-34. [PMID: 21953548 DOI: 10.1002/art.33377] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Previous studies have demonstrated that, once released into the extracellular environment, the systemic sclerosis (SSc)-associated autoantigen DNA topoisomerase I (topo I) binds specifically to the surface of fibroblasts via an unknown receptor. We extended these results by identifying topo I-mediated cellular effects and characterizing the specific target of topo I on fibroblast surfaces. METHODS Purified topo I was used to investigate intracellular signaling pathway activation and tested for cell migration. To demonstrate the expression of specific chemokine receptors on fibroblasts, we performed immunoblotting and flow cytometry. To evaluate the direct interaction between chemokine receptor and topo I, a protein-protein based enzyme-linked immunosorbent assay (ELISA) was used. Finally, topo I coupled to the fluorochrome phycoerythrin (PE) was used to investigate competition of topo I specific binding on fibroblast surfaces with chemokine ligand. RESULTS Topo I stimulated the phosphorylation of phospholipase Cγ1, c-Raf, ERK-1/2, and p38 MAPK, intracellular signaling pathways that stimulated fibroblast migration via a G(αi) protein-coupled receptor. CCR7 was found to interact directly with topo I. Furthermore, its ligand, CCL21, competed in vitro for this interaction and in vivo with the binding of PE-coupled topo I to fibroblast surfaces. CONCLUSION These new roles of topo I in fibroblast physiology and the identification of its target on the cell surface demonstrate that topo I is a bifunctional autoantigen and open up new perspectives of study in the field of SSc-associated anti-topo I autoantibodies.
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Affiliation(s)
- Julie Arcand
- Laboratory for Research in Autoimmunity, Notre-Dame Hospital, Centre Hospitalier de l'Université de Montréal, and Université de Montréal, Montréal, Québec, Canada
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Polizio AH, Chinchilla P, Chen X, Manning DR, Riobo NA. Sonic Hedgehog activates the GTPases Rac1 and RhoA in a Gli-independent manner through coupling of smoothened to Gi proteins. Sci Signal 2011; 4:pt7. [PMID: 22114142 DOI: 10.1126/scisignal.2002396] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The vertebrate Hedgehog (Hh) pathway has essential functions during development and tissue homeostasis in normal physiology, and its dysregulation is a common theme in cancer. The Hh ligands (Sonic Hh, Indian Hh, and Desert Hh) bind to the receptors Patched1 and Patched2, resulting in inhibition of their repressive effect on Smoothened (Smo). Smo is a seven-transmembrane protein, which was only recently shown to function as a G protein-coupled receptor (GPCR) with specificity toward the heterotrimeric guanine nucleotide-binding protein G(i). In addition to activating G(i), Smo signals through its C-terminal tail to inhibit Suppressor of Fused, resulting in stabilization and activation of the Gli family of transcription factors, which execute a transcriptional response to so-called "canonical Hh signaling." In this Presentation, we illustrate two outcomes of Hh signaling that are independent of Gli transcriptional activity and, thus, are defined as "noncanonical." One outcome is dependent on Smo coupling to G(i) proteins and exerts changes to the actin cytoskeleton through stimulation of the small guanosine triphosphatases (GTPases) RhoA and Rac1. These cytoskeletal changes promote migration in fibroblasts and tubulogenesis in endothelial cells. Signaling through the other noncanonical Hh pathway is independent of Smo and inhibits Patched1-induced cell death.
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Affiliation(s)
- Ariel H Polizio
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Guan X, Fierke CA. Understanding Protein Palmitoylation: Biological Significance and Enzymology. Sci China Chem 2011; 54:1888-1897. [PMID: 25419213 DOI: 10.1007/s11426-011-4428-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Protein palmitoylation is a widespread lipid modification in which one or more cysteine thiols on a substrate protein are modified to form a thioester with a palmitoyl group. This lipid modification is readily reversible; a feature of protein palmitoylation that allows for rapid regulation of the function of many cellular proteins. Mutations in palmitoyltransferases (PATs), the enzymes that catalyze the formation of this modification, are associated with a number of neurological diseases and cancer progression. This review summarizes the crucial role of palmitoylation in biological systems, the discovery of the DHHC protein family that catalyzes protein palmitoylation, and the development of methods for investigating the catalytic mechanism of PATs.
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Affiliation(s)
- Xiaomu Guan
- Departments of Chemistry and Biological Chemistry, University of Michigan, 930 N University, Ann Arbor, MI 48109-1055, USA
| | - Carol A Fierke
- Departments of Chemistry and Biological Chemistry, University of Michigan, 930 N University, Ann Arbor, MI 48109-1055, USA
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Fujita H, Kato T, Watanabe N, Takahashi T, Kitagawa S. Calpain inhibitors stimulate phagocyte functions via activation of human formyl peptide receptors. Arch Biochem Biophys 2011; 513:51-60. [DOI: 10.1016/j.abb.2011.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/10/2011] [Accepted: 06/16/2011] [Indexed: 11/30/2022]
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Mangmool S, Kurose H. G(i/o) protein-dependent and -independent actions of Pertussis Toxin (PTX). Toxins (Basel) 2011; 3:884-99. [PMID: 22069745 PMCID: PMC3202852 DOI: 10.3390/toxins3070884] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 06/14/2011] [Accepted: 06/16/2011] [Indexed: 12/22/2022] Open
Abstract
Pertussis toxin (PTX) is a typical A-B toxin. The A-protomer (S1 subunit) exhibits ADP-ribosyltransferase activity. The B-oligomer consists of four subunits (S2 to S5) and binds extracellular molecules that allow the toxin to enter the cells. The A-protomer ADP-ribosylates the α subunits of heterotrimeric Gi/o proteins, resulting in the receptors being uncoupled from the Gi/o proteins. The B-oligomer binds proteins expressed on the cell surface, such as Toll-like receptor 4, and activates an intracellular signal transduction cascade. Thus, PTX modifies cellular responses by at least two different signaling pathways; ADP-ribosylation of the Gαi/o proteins by the A-protomer (Gi/o protein-dependent action) and the interaction of the B-oligomer with cell surface proteins (Gi/o protein-independent action).
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya, Rajathevi, Bangkok 10400, Thailand;
| | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
- Author to whom correspondence should be addressed; ; Tel.: +81-92-642-6884; Fax: +81-92-642-6884
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Lee EY, Seo M, Juhnn YS, Kim JY, Hong YJ, Lee YJ, Lee EB, Song YW. Potential role and mechanism of IFN-gamma inducible protein-10 on receptor activator of nuclear factor kappa-B ligand (RANKL) expression in rheumatoid arthritis. Arthritis Res Ther 2011; 13:R104. [PMID: 21708014 PMCID: PMC3218919 DOI: 10.1186/ar3385] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/07/2011] [Accepted: 06/27/2011] [Indexed: 11/17/2022] Open
Abstract
Introduction IFN-gamma inducible protein-10 (CXCL10), a member of the CXC chemokine family, and its receptor CXCR3 contribute to the recruitment of T cells from the blood stream into the inflamed joints and have a crucial role in perpetuating inflammation in rheumatoid arthritis (RA) synovial joints. Recently we showed the role of CXCL10 on receptor activator of nuclear factor kappa-B ligand (RANKL) expression in an animal model of RA and suggested the contribution to osteoclastogenesis. We tested the effects of CXCL10 on the expression of RANKL in RA synoviocytes and T cells, and we investigated which subunit of CXCR3 contributes to RANKL expression by CXCL10. Methods Synoviocytes derived from RA patients were kept in culture for 24 hours in the presence or absence of TNF-α. CXCL10 expression was measured by reverse transcriptase polymerase chain reaction (RT-PCR) of cultured synoviocytes. Expression of RANKL was measured by RT-PCR and western blot in cultured synoviocytes with or without CXCL10 and also measured in Jurkat/Hut 78 T cells and CD4+ T cells in the presence of CXCL10 or dexamethasone. CXCL10 induced RANKL expression in Jurkat T cells was tested upon the pertussis toxin (PTX), an inhibitor of Gi subunit of G protein coupled receptor (GPCR). The synthetic siRNA for Gαi2 was used to knock down gene expression of respective proteins. Results CXCL10 expression in RA synoviocytes was increased by TNF-α. CXCL10 slightly increased RANKL expression in RA synoviocytes, but markedly increased RANKL expression in Jurkat/Hut 78 T cell or CD4+ T cell. CXCL10 augmented the expression of RANKL by 62.6%, and PTX inhibited both basal level of RANKL (from 37.4 ± 16.0 to 18.9 ± 13.0%) and CXCL10-induced RANKL expression in Jurkat T cells (from 100% to 48.6 ± 27.3%). Knock down of Gαi2 by siRNA transfection, which suppressed the basal level of RANKL (from 61.8 ± 17.9% to 31.1 ± 15.9%) and CXCL10-induced RANKL expression (from 100% to 53.1 ± 27.1%) in Jurkat T cells, is consistent with PTX, which inhibited RANKL expression. Conclusions CXCL10 increased RANKL expression in CD4+ T cells and it was mediated by Gαi subunits of CXCR3. These results indicate that CXCL10 may have a potential role in osteoclastogenesis of RA synovial tissue and subsequent joint erosion.
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Affiliation(s)
- Eun Young Lee
- Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul, 110-744, Republic of Korea
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Byrnes JJ, Gleason ED, Schoen MK, Schoen MT, Lovelock DF, Carini LM, Byrnes EM, Bridges RS. Accelerated maternal responding following intra-VTA pertussis toxin treatment. Behav Brain Res 2011; 223:322-8. [PMID: 21571006 DOI: 10.1016/j.bbr.2011.04.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/25/2011] [Accepted: 04/28/2011] [Indexed: 12/21/2022]
Abstract
Prior studies have supported a role for mesolimbic dopaminergic mechanisms in the regulation of maternal behavior. Accordingly, the ventral tegmental area (VTA) and its dopaminergic projections to the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) have been implicated in both the onset and maintenance of normal maternal behavior. To date, studies of direct manipulation of VTA neurochemistry at the onset of maternal behavior have been limited. The current study was undertaken to directly test the hypothesis that enhancement of dopaminergic transmission in the mesolimbic dopamine system can stimulate maternal activity using a pup-induced virgin model. Nulliparous female rats were stereotaxically infused with pertussis toxin (PTX 0, 0.1, or 0.3 μg/hemisphere) into the VTA to chronically stimulate the activity of dopaminergic projection neurons. After 3 days of recovery, maternal responding to donor pups was tested daily, and latency (in days) to full maternal behavior was recorded. Intra-VTA PTX treatment produced a robust dose-dependent decrease in maternal behavior latency, and a long-lasting increase in locomotor activity. These effects were associated with significantly decreased dopamine D1 receptor mRNA expression in the NAc. No effects of PTX treatment on mesolimbic dopamine utilization or mPFC receptor expression were observed. The findings indicate that chronic neural activation in the VTA accelerates the onset of maternal behavior in virgin female rats via modification of the NAc dopamine D1 receptor.
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Affiliation(s)
- John J Byrnes
- Department of Biomedical Sciences Section of Reproduction and Neuroscience, Tufts University, Cummings School of Veterinary Medicine, North Grafton, MA 01536, USA
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Wang Y, Ma T, Li M, Sun X, Wang Y, Gu S. Regulated hypoxia/reperfusion-dependent modulation of ERK1/2, cPLA2, and Bcl-2/Bax: a potential mechanism of neuroprotective effect of penehyclidine hydrochloride. Int J Neurosci 2011; 121:442-9. [PMID: 21545309 DOI: 10.3109/00207454.2011.570611] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The activation of event-related kinase 1/2 (ERK1/2) and cytosolic phospholipaseA2 (cPLA2), which can aggravate hypoxia/reoxygenation (H/R) damage related to their downstream Bcl-2/Bax and Caspase-3 pathway, plays a key role in H/R. The M1 receptors could be responsible for activation of ERK1/2. Thus, it seems that the regulation of M1 receptors mediated the ERK1/2; cPLA2-mediated Bcl-2/Bax pathway may be a significant responsive signal in H/R. Penehyclidine hydrochloride (PHC) is an anticholinergic agent with high degree of selectivity for M1 and M3 receptor subtypes, it is reported that PHC has a protective effect against H/R damage. Here we hypothesize and demonstrate that PHC could downregulate the expression of pERK1/2, cPLA2, and Caspase-3, increased the ratio of Bcl-2/Bax. This study may widen the application of PHC and therapeutic agents of stroke.
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Affiliation(s)
- Yun Wang
- Department of Pharmacology, XuZhou Medical College, XuZhou, Jiangsu, China
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Affiliation(s)
- Ghanshyam N Pandey
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 1601 West Taylor Street, Chicago, IL 60612
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Li QF, Zhu HY, Yang YF, Liu J, Xiao FJ, Zhang QW, Wu CT, Wang H, Wang LS. Prokineticin-1/endocrine gland-derived vascular endothelial growth factor is a survival factor for human multiple myeloma cells. Leuk Lymphoma 2011; 51:1902-12. [PMID: 20795791 DOI: 10.3109/10428194.2010.512963] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Prokineticin-1 (PK1) has been identified as a mitogen-specific protein for the endothelium of steroidogenic glands. Here we report a novel function of PK1 in the regulation of multiple myeloma (MM) cells. PK1 activates multiple signals including mitogen-activated protein kinase (MAPK), PI3K-AKT, and Jak-STAT3, sphingosine kinase-1 (SPK1) in MM cells. Treatment of MM cells with PK1 causes a time- and dose-dependent phosphorylation of MAPK, AKT and STAT3 and upregulation of SPK1 expression and cellular activity. We also show that PK1 upregulates Mcl-1 expression in a time- and dose-dependent manner in human MM cell lines and in the cells of patients with MM. Pertussis toxin, a pan-PK1 receptor inhibitor, can block PK1-induced upregulation of Mcl-1, indicating it relates to a G-protein-coupled receptor. We also show that PK1 protects MM cells against apoptosis induced by starvation for fetal calf serum (FBS), or for FBS and IL-6. Taken together, PK1 activates multiple signaling pathways and, upregulates Mcl-1 expression, leading to proliferation and survival of MM cells.
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Affiliation(s)
- Qing-Fang Li
- Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing, People's Republic of China
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43
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Kupchik Y, Parnas H, Parnas I. A novel, extremely fast, feedback inhibition of glutamate release in the crayfish neuromuscular junction. Neuroscience 2011; 172:44-54. [DOI: 10.1016/j.neuroscience.2010.10.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 10/19/2010] [Accepted: 10/19/2010] [Indexed: 11/27/2022]
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Orie NN, Clapp LH. Role of prostanoid IP and EP receptors in mediating vasorelaxant responses to PGI2 analogues in rat tail artery: Evidence for Gi/o modulation via EP3 receptors. Eur J Pharmacol 2010; 654:258-65. [PMID: 21185823 DOI: 10.1016/j.ejphar.2010.12.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 11/17/2010] [Accepted: 12/11/2010] [Indexed: 10/18/2022]
Abstract
Prostanoid IP receptors coupled to Gs are thought to be the primary target for prostacyclin (PGI(2)) analogues. However, these agents also activate prostanoid EP(1-4) receptor subtypes to varying degrees, which are positively (EP(2/4)) or negatively (EP(3)) coupled to adenylate cyclase through Gs or Gi, respectively. We investigated the role of these receptors in modulating relaxation to PGI(2) analogues cicaprost, iloprost and treprostinil in pre-contracted segments of rat tail artery. Prostanoid IP (RO1138452), EP(4) (GW627368X), EP(3) (L-798106), EP(1-3) (AH6809), and EP(1) (SC-51322) receptor antagonists were used to determine each receptor contribution. The role of G(i/o) was investigated using pertussis toxin (PTX), while dependence on cAMP was determined using adenylate cyclase (2'5'dideoxyadenosine, DDA) and protein kinase A (2'-O-monobutyryladenosine- 3',5'-cyclic monophosphorothioate, Rp- isomer, Rp-2'-O-MB-cAMPS) inhibitors, and by measurement of tissue cAMP. All analogues caused relaxation which was significantly (P<0.01) inhibited by RO1138452; with maximum response to cicaprost, iloprost and treprostinil reduced by 51%, 66% and 37%, respectively. GW627368X had no effect when used alone, but in combination with RO1138452, caused a rightward shift of the curves for cicaprost and iloprost but not treprostinil. PTX treatment potentiated relaxation to all 3 analogues (P<0.01), as did L798106 and AH6809 but not SC-51322. Basal cAMP levels were higher in PTX-treated tissues and DDA- and Rp-2'-O-MB-cAMPs--sensitive responses increased to analogue concentrations <0.1μM. In conclusion, prostanoid EP(3) receptors via G(i/o) negatively modulate prostanoid IP receptor-mediated relaxation to cicaprost, iloprost and treprostinil. However, other pathways contribute to analogue-induced vasorelaxation, the nature of which remains unclear for treprostinil.
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Affiliation(s)
- Nelson N Orie
- BHF Laboratories, Department of Medicine, University College London, 5 University Street, London, WC1E 6JF, UK.
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Wilson BA, Ho M. Recent insights into Pasteurella multocida toxin and other G-protein-modulating bacterial toxins. Future Microbiol 2010; 5:1185-201. [PMID: 20722598 DOI: 10.2217/fmb.10.91] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Over the past few decades, our understanding of the bacterial protein toxins that modulate G proteins has advanced tremendously through extensive biochemical and structural analyses. This article provides an updated survey of the various toxins that target G proteins, ending with a focus on recent mechanistic insights in our understanding of the deamidating toxin family. The dermonecrotic toxin from Pasteurella multocida (PMT) was recently added to the list of toxins that disrupt G-protein signal transduction through selective deamidation of their targets. The C3 deamidase domain of PMT has no sequence similarity to the deamidase domains of the dermonecrotic toxins from Escherichia coli (cytotoxic necrotizing factor [CNF]1-3), Yersinia (CNFY) and Bordetella (dermonecrotic toxin). The structure of PMT-C3 belongs to a family of transglutaminase-like proteins, with active site Cys-His-Asp catalytic triads distinct from E. coli CNF1.
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Affiliation(s)
- Brenda A Wilson
- Department of Microbiology and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave, B128 CLSL, Urbana, IL 61801, USA.
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Cerella C, Cordisco S, Albertini MC, Accorsi A, Diederich M, Ghibelli L. Magnetic fields promote a pro-survival non-capacitative Ca2+ entry via phospholipase C signaling. Int J Biochem Cell Biol 2010; 43:393-400. [PMID: 21095240 DOI: 10.1016/j.biocel.2010.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 11/04/2010] [Accepted: 11/15/2010] [Indexed: 11/28/2022]
Abstract
The ability of magnetic fields (MFs) to promote/increase Ca(2+) influx into cells is widely recognized, but the underlying mechanisms remain obscure. Here we analyze how static MFs of 6 mT modulates thapsigargin-induced Ca(2+) movements in non-excitable U937 monocytes, and how this relates to the anti-apoptotic effect of MFs. Magnetic fields do not affect thapsigargin-induced Ca(2+) mobilization from endoplasmic reticulum, but significantly increase the resulting Ca(2+) influx; this increase requires intracellular signal transduction actors including G protein, phospholipase C, diacylglycerol lipase and nitric oxide synthase, and behaves as a non-capacitative Ca(2+) entry (NCCE), a type of influx with an inherent signaling function, rather than a capacitative Ca(2+) entry (CCE). All treatments abrogating the extra Ca(2+) influx also abrogate the anti-apoptotic effect of MFs, demonstrating that MF-induced NCCE elicits an anti-apoptotic survival pathway.
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Affiliation(s)
- Claudia Cerella
- Dipartimento di Biologia, Universita' degli Studi di Roma Tor Vergata, Via della Ricerca Scientifica snc, 00133 Roma, Italy
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Temple BRS, Jones CD, Jones AM. Evolution of a signaling nexus constrained by protein interfaces and conformational States. PLoS Comput Biol 2010; 6:e1000962. [PMID: 20976244 PMCID: PMC2954821 DOI: 10.1371/journal.pcbi.1000962] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 09/17/2010] [Indexed: 01/03/2023] Open
Abstract
Heterotrimeric G proteins act as the physical nexus between numerous receptors that respond to extracellular signals and proteins that drive the cytoplasmic response. The Gα subunit of the G protein, in particular, is highly constrained due to its many interactions with proteins that control or react to its conformational state. Various organisms contain differing sets of Gα-interacting proteins, clearly indicating that shifts in sequence and associated Gα functionality were acquired over time. These numerous interactions constrained much of Gα evolution; yet Gα has diversified, through poorly understood processes, into several functionally specialized classes, each with a unique set of interacting proteins. Applying a synthetic sequence-based approach to mammalian Gα subunits, we established a set of seventy-five evolutionarily important class-distinctive residues, sites where a single Gα class is differentiated from the three other classes. We tested the hypothesis that shifts at these sites are important for class-specific functionality. Importantly, we mapped known and well-studied class-specific functionalities from all four mammalian classes to sixteen of our class-distinctive sites, validating the hypothesis. Our results show how unique functionality can evolve through the recruitment of residues that were ancestrally functional. We also studied acquisition of functionalities by following these evolutionarily important sites in non-mammalian organisms. Our results suggest that many class-distinctive sites were established early on in eukaryotic diversification and were critical for the establishment of new Gα classes, whereas others arose in punctuated bursts throughout metazoan evolution. These Gα class-distinctive residues are rational targets for future structural and functional studies.
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Affiliation(s)
- Brenda R S Temple
- R. L. Juliano Structural Bioinformatics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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Yang YM, Lee S, Nam CW, Ha JH, Jayaraman M, Dhanasekaran DN, Lee CH, Kwak MK, Kim SG. G(alpha)12/13 inhibition enhances the anticancer effect of bortezomib through PSMB5 downregulation. Carcinogenesis 2010; 31:1230-7. [PMID: 20478922 DOI: 10.1093/carcin/bgq097] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bortezomib is a proteasome inhibitor approved for anticancer therapy. However, variable sensitivity of tumor cells exists in this therapy probably due to differences in the expression of proteasome subunits. G(alpha)(12/13) serves modulators or signal transducers in diverse pathways. This study investigated whether cancer cells display differential sensitivity to bortezomib with reference to G(alpha)(12/13) expression, and if so, whether G(alpha)(12/13) affects the expression of proteasome subunits and their activities. Bortezomib treatment exhibited greater sensitivities in Huh7 and SNU886 cells (epithelial type) than SK-Hep1 and SNU449 cells (mesenchymal type) that exhibited higher levels of G(alpha)(12/13). Overexpression of an active mutant of G(alpha)(12) (Galpha(12)QL) or G(alpha)(13) (G(alpha)(13)QL) diminished the ability of bortezomib to induce cytotoxicity in Huh7 cells. Moreover, transfection with the minigene that disturbs G protein-coupled receptor-G protein coupling (CT12 or CT13) increased it in SK-Hep1 cells. Consistently, MiaPaCa2 cells transfected with CT12 or CT13 exhibited a greater sensitivity to bortezomib. Evidence of G(alpha)(12/13)'s antagonism on the anticancer effect of bortezomib was verified in the reversal by G(alpha)(12)QL or G(alpha)(13)QL of the minigenes' enhancement of cytotoxity. Real-time polymerase chain reaction assay enabled us to identify PSMB5, multicatalytic endopeptidase complex-like-1, and proteasome activator subunit-1 repression by CT12 or CT13. Furthermore, G(alpha)(12/13) inhibition enhanced the ability of bortezomib to repress PSMB5, as shown by immunoblotting and proteasome activity assay. Moreover, this inhibitory effect on PSMB5 was attenuated by G(alpha)G(alpha)(12)QL or G(alpha)(13)QL. In conclusion, the inhibition of G(alpha)(12/13) activities may enhance the anticancer effect of bortezomib through PSMB5 repression, providing insight into the G(alpha)(12/13) pathway for the regulation of proteasomal activity.
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Affiliation(s)
- Yoon Mee Yang
- Department of Pharmacy, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, Korea
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Grzelinski M, Pinkenburg O, Büch T, Gold M, Stohr S, Kalwa H, Gudermann T, Aigner A. Critical role of G(alpha)12 and G(alpha)13 for human small cell lung cancer cell proliferation in vitro and tumor growth in vivo. Clin Cancer Res 2010; 16:1402-15. [PMID: 20160064 DOI: 10.1158/1078-0432.ccr-09-1873] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE In small cell lung cancer cells (SCLC), various autocrine stimuli lead to the parallel activation of G(q/11) and G(12/13) proteins. Although the contribution of the G(q/11)-phospholipase C-beta cascade to mitogenic effects in SCLC cells is well established, the relevance of G(12/13) signaling is still elusive. In other tumor entities, G(12/13) activation promotes invasiveness without affecting cellular proliferation. Here, we investigate the role of G(12/13)-dependent signaling in SCLC. EXPERIMENTAL DESIGN We used small hairpin RNA-mediated targeting of G(alpha)(12), G(alpha)(13), or both in H69 and H209 cells and analyzed the effects of G(alpha)(12) and/or G(alpha)(13) knockdown on tumor cells in vitro, tumor growth in vivo, and mitogen-activated protein kinase (MAPK) activation. RESULTS Lentiviral expression of small hairpin RNAs resulted in robust and specific G(alpha)(12) and G(alpha)(13) knockdown as well as markedly inhibited proliferation, colony formation, and bradykinin-promoted stimulation of cell growth. Analyzing the activation status of all three major MAPK families revealed nonredundant functions of G(alpha)(12) and G(alpha)(13) in SCLC and a marked p42/p44 activation upon G(alpha)(12)/G(alpha)(13) knockdown. In a s.c. tumor xenograft mouse model, G(alpha)(12) or G(alpha)(13) downregulation led to decreased tumor growth due to reduced tumor cell proliferation. More importantly, G(alpha)(12)/G(alpha)(13) double knockdown completely abolished H69 tumorigenicity in mice. CONCLUSIONS G(alpha)(12) and G(alpha)13) exert a complex pattern of nonredundant effects in SCLC, and in contrast to other tumor types, SCLC cell proliferation in vitro and tumorigenicity in vivo critically depend on G(12/13) signaling. Due to the complete abolishment of tumorgenicity in our study, RNAi-mediated double knockdown may provide a promising new avenue in SCLC treatment.
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Affiliation(s)
- Marius Grzelinski
- Department of Pharmacology and Toxicology, Philipps-University School of Medicine, Marburg, Germany
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Neospora caninum excreted/secreted antigens trigger CC-chemokine receptor 5-dependent cell migration. Int J Parasitol 2010; 40:797-805. [PMID: 20060395 DOI: 10.1016/j.ijpara.2009.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Revised: 12/04/2009] [Accepted: 12/06/2009] [Indexed: 01/10/2023]
Abstract
Neospora caninum, the causative agent of neosporosis, is an obligate intracellular parasite considered to be a major cause of abortion in cattle throughout the world. Most studies concerning N. caninum have focused on life cycle, seroepidemiology, pathology and vaccination, while data on host-parasite interaction, such as host cell migration, mechanisms of evasion and dissemination of this parasite during the early phase of infection are still poorly understood. Here we show the ability of excreted/secreted antigens from N. caninum (NcESAs) to attract monocytic cells to the site of primary infection in both in vitro and in vivo assays. Molecules from the family of cyclophilins present on the NcESAs were shown to work as chemokine-like proteins and NcESA-induced chemoattraction involved G(i) protein signaling and participation of CC-chemokine receptor 5 (CCR5). Additionally, we demonstrate the ability of NcESAs to enhance the expression of CCR5 on monocytic cells and this increase occurred in parallel with the chemotactic activity of NcESAs by increasing cell migration. These results suggest that during the first days of infection, N. caninum produces molecules capable of inducing monocytic cell migration to the sites of infection, which will consequently enhance initial parasite invasion and proliferation. Altogether, these results help to clarify some key features involved in the process of cell migration and may reveal virulence factors and therapeutic targets to control neosporosis.
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