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Jallouli R, Moreno Salinas AL, Laniel A, Holleran B, Avet C, Jacob J, Hoang T, Lavoie C, Carmon KS, Bouvier M, Leduc R. G protein selectivity profile of GPR56/ADGRG1 and its effect on downstream effectors. RESEARCH SQUARE 2024:rs.3.rs-4869264. [PMID: 39281883 PMCID: PMC11398566 DOI: 10.21203/rs.3.rs-4869264/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/18/2024]
Abstract
GPR56, an adhesion G-protein coupled receptor (aGPCRs) with constitutive and ligand-promoted activity, is involved in many physiological and pathological processes. Whether the receptor's constitutive or ligand-promoted activation occur through the same molecular mechanism, and whether different activation modes lead to functional selectivity between G proteins is unknown. Here we show that GPR56 constitutively activates both G12 and G13. Unlike constitutive activation and activation with 3-a-acetoxydihydrodeoxygedunin (3αDOG), stimulation with an antibody, 10C7, directed against GPR56's extracellular domain (ECD) led to an activation that favors G13 over G12. An autoproteolytically deficient mutant, GPR56-T383A, was also activated by 10C7 indicating that the tethered agonist (TA) exposed through autocatalytic cleavage, is not required for this activation modality. In contrast, this proteolysis-resistant mutant could not be activated by 3αDOG indicating different modes of activation by the two ligands. We show that an N-terminal truncated GPR56 construct (GPR56-Δ1-385) is devoid of constitutive activity but was activated by 3αDOG. Similarly to 3αDOG, 10C7 promoted the recruitment of b-arrestin-2 but GPR56 internalization was β-arrestin independent. Despite the slow activation mode of 10C7 that favors G13 over G12, it efficiently activated the downstream Rho pathway in BT-20 breast cancer cells. These data show that different GPR56 ligands have different modes of activation yielding differential G protein selectivity but converging on the activation of the Rho pathway both in heterologous expressions system and in cancer cells endogenously expressing the receptor. 10C7 is therefore an interesting tool to study both the processes underlying GPR56 activity and its role in cancer cells.
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Affiliation(s)
| | | | | | | | | | - Joan Jacob
- The University of Texas MD Anderson Cancer Center
| | - Trang Hoang
- University of Montreal: Universite de Montreal
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2
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Jallouli R, Moreno-Salinas AL, Laniel A, Holleran B, Avet C, Jacob J, Hoang T, Lavoie C, Carmon KS, Bouvier M, Leduc R. G protein selectivity profile of GPR56/ADGRG1 and its effect on downstream effectors. Cell Mol Life Sci 2024; 81:383. [PMID: 39231834 PMCID: PMC11374949 DOI: 10.1007/s00018-024-05416-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 08/08/2024] [Accepted: 08/17/2024] [Indexed: 09/06/2024]
Abstract
GPR56, an adhesion G-protein coupled receptor (aGPCRs) with constitutive and ligand-promoted activity, is involved in many physiological and pathological processes. Whether the receptor's constitutive or ligand-promoted activation occur through the same molecular mechanism, and whether different activation modes lead to functional selectivity between G proteins is unknown. Here we show that GPR56 constitutively activates both G12 and G13. Unlike constitutive activation and activation with 3-α-acetoxydihydrodeoxygedunin (3αDOG), stimulation with an antibody, 10C7, directed against GPR56's extracellular domain (ECD) led to an activation that favors G13 over G12. An autoproteolytically deficient mutant, GPR56-T383A, was also activated by 10C7 indicating that the tethered agonist (TA) exposed through autocatalytic cleavage, is not required for this activation modality. In contrast, this proteolysis-resistant mutant could not be activated by 3αDOG indicating different modes of activation by the two ligands. We show that an N-terminal truncated GPR56 construct (GPR56-Δ1-385) is devoid of constitutive activity but was activated by 3αDOG. Similarly to 3αDOG, 10C7 promoted the recruitment of β-arrestin-2 but GPR56 internalization was β-arrestin independent. Despite the slow activation mode of 10C7 that favors G13 over G12, it efficiently activated the downstream Rho pathway in BT-20 breast cancer cells. These data show that different GPR56 ligands have different modes of activation yielding differential G protein selectivity but converging on the activation of the Rho pathway both in heterologous expressions system and in cancer cells endogenously expressing the receptor. 10C7 is therefore an interesting tool to study both the processes underlying GPR56 activity and its role in cancer cells.
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Affiliation(s)
- Raida Jallouli
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Ana L Moreno-Salinas
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Andréanne Laniel
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Brian Holleran
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Charlotte Avet
- Institute for Research in Immunology and Cancer (IRIC), Department of Pharmacology and Physiology, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Canada
| | - Joan Jacob
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, USA
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Trang Hoang
- Institute for Research in Immunology and Cancer (IRIC), Department of Pharmacology and Physiology, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Canada
| | - Christine Lavoie
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Kendra S Carmon
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, USA
- Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Michel Bouvier
- Institute for Research in Immunology and Cancer (IRIC), Department of Pharmacology and Physiology, Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Canada.
| | - Richard Leduc
- Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
- Institut de Pharmacologie de Sherbrooke, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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McDuffie EL, Panettieri RA, Scott CP. G 12/13 signaling in asthma. Respir Res 2024; 25:295. [PMID: 39095798 PMCID: PMC11297630 DOI: 10.1186/s12931-024-02920-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 07/19/2024] [Indexed: 08/04/2024] Open
Abstract
Shortening of airway smooth muscle and bronchoconstriction are pathognomonic for asthma. Airway shortening occurs through calcium-dependent activation of myosin light chain kinase, and RhoA-dependent calcium sensitization, which inhibits myosin light chain phosphatase. The mechanism through which pro-contractile stimuli activate calcium sensitization is poorly understood. Our review of the literature suggests that pro-contractile G protein coupled receptors likely signal through G12/13 to activate RhoA and mediate calcium sensitization. This hypothesis is consistent with the effects of pro-contractile agonists on RhoA and Rho kinase activation, actin polymerization and myosin light chain phosphorylation. Recognizing the likely role of G12/13 signaling in the pathophysiology of asthma rationalizes the effects of pro-contractile stimuli on airway hyperresponsiveness, immune activation and airway remodeling, and suggests new approaches for asthma treatment.
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Affiliation(s)
- Elizabeth L McDuffie
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, NJ, USA
| | - Charles P Scott
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
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4
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Peng Y, Du J, Li R, Günther S, Wettschureck N, Offermanns S, Wang Y, Schneider A, Braun T. RhoA-mediated G 12-G 13 signaling maintains muscle stem cell quiescence and prevents stem cell loss. Cell Discov 2024; 10:76. [PMID: 39009565 PMCID: PMC11251043 DOI: 10.1038/s41421-024-00696-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/27/2024] [Indexed: 07/17/2024] Open
Abstract
Multiple processes control quiescence of muscle stem cells (MuSCs), which is instrumental to guarantee long-term replenishment of the stem cell pool. Here, we describe that the G-proteins G12-G13 integrate signals from different G-protein-coupled receptors (GPCRs) to control MuSC quiescence via activation of RhoA. Comprehensive screening of GPCR ligands identified two MuSC-niche-derived factors, endothelin-3 (ET-3) and neurotensin (NT), which activate G12-G13 signaling in MuSCs. Stimulation with ET-3 or NT prevented MuSC activation, whereas pharmacological inhibition of ET-3 or NT attenuated MuSC quiescence. Inactivation of Gna12-Gna13 or Rhoa but not of Gnaq-Gna11 completely abrogated MuSC quiescence, which depleted the MuSC pool and was associated with accelerated sarcopenia during aging. Expression of constitutively active RhoA prevented exit from quiescence in Gna12-Gna13 mutant MuSCs, inhibiting cell cycle entry and differentiation via Rock and formins without affecting Rac1-dependent MuSC projections, a hallmark of quiescent MuSCs. The study uncovers a critical role of G12-G13 and RhoA signaling for active regulation of MuSC quiescence.
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Affiliation(s)
- Yundong Peng
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
| | - Jingjing Du
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Rui Li
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Stefan Günther
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Nina Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Member of the German Center for Cardiovascular Research (DZHK), member of the German Center for Lung Research (DZL), Berlin, Germany
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Member of the German Center for Cardiovascular Research (DZHK), member of the German Center for Lung Research (DZL), Berlin, Germany
| | - Yan Wang
- College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Andre Schneider
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
- Member of the German Center for Cardiovascular Research (DZHK), member of the German Center for Lung Research (DZL), Berlin, Germany.
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Wu D, Casey PJ. GPCR-Gα13 Involvement in Mitochondrial Function, Oxidative Stress, and Prostate Cancer. Int J Mol Sci 2024; 25:7162. [PMID: 39000269 PMCID: PMC11241654 DOI: 10.3390/ijms25137162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/20/2024] [Accepted: 06/26/2024] [Indexed: 07/16/2024] Open
Abstract
Gα13 and Gα12, encoded by the GNA13 and GNA12 genes, respectively, are members of the G12 family of Gα proteins that, along with their associated Gβγ subunits, mediate signaling from specific G protein-coupled receptors (GPCRs). Advanced prostate cancers have increased expression of GPCRs such as CXC Motif Chemokine Receptor 4 (CXCR4), lysophosphatidic acid receptor (LPAR), and protease activated receptor 1 (PAR-1). These GPCRs signal through either the G12 family, or through Gα13 exclusively, often in addition to other G proteins. The effect of Gα13 can be distinct from that of Gα12, and the role of Gα13 in prostate cancer initiation and progression is largely unexplored. The oncogenic effect of Gα13 on cell migration and invasion in prostate cancer has been characterized, but little is known about other biological processes such as mitochondrial function and oxidative stress. Current knowledge on the link between Gα13 and oxidative stress is based on animal studies in which GPCR-Gα13 signaling decreased superoxide levels, and the overexpression of constitutively active Gα13 promoted antioxidant gene activation. In human samples, mitochondrial superoxide dismutase 2 (SOD2) correlates with prostate cancer risk and prognostic Gleason grade. However, overexpression of SOD2 in prostate cancer cells yielded conflicting results on cell growth and survival under basal versus oxidative stress conditions. Hence, it is necessary to explore the effect of Gα13 on prostate cancer tumorigenesis, as well as the effect of Gα13 on SOD2 in prostate cancer cell growth under oxidative stress conditions.
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Affiliation(s)
- Di Wu
- Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore;
| | - Patrick J. Casey
- Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore;
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, 308 Research Drive, Durham, NC 27710, USA
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Saito A, Kise R, Inoue A. Generation of Comprehensive GPCR-Transducer-Deficient Cell Lines to Dissect the Complexity of GPCR Signaling. Pharmacol Rev 2024; 76:599-619. [PMID: 38719480 DOI: 10.1124/pharmrev.124.001186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 06/16/2024] Open
Abstract
G-protein-coupled receptors (GPCRs) compose the largest family of transmembrane receptors and are targets of approximately one-third of Food and Drug Administration-approved drugs owing to their involvement in almost all physiologic processes. GPCR signaling occurs through the activation of heterotrimeric G-protein complexes and β-arrestins, both of which serve as transducers, resulting in distinct cellular responses. Despite seeming simple at first glance, accumulating evidence indicates that activation of either transducer is not a straightforward process as a stimulation of a single molecule has the potential to activate multiple signaling branches. The complexity of GPCR signaling arises from the aspects of G-protein-coupling selectivity, biased signaling, interpathway crosstalk, and variable molecular modifications generating these diverse signaling patterns. Numerous questions relative to these aspects of signaling remained unanswered until the recent development of CRISPR genome-editing technology. Such genome editing technology presents opportunities to chronically eliminate the expression of G-protein subunits, β-arrestins, G-protein-coupled receptor kinases (GRKs), and many other signaling nodes in the GPCR pathways at one's convenience. Here, we review the practicality of using CRISPR-derived knockout (KO) cells in the experimental contexts of unraveling the molecular details of GPCR signaling mechanisms. To mention a few, KO cells have revealed the contribution of β-arrestins in ERK activation, Gα protein selectivity, GRK-based regulation of GPCRs, and many more, hence validating its broad applicability in GPCR studies. SIGNIFICANCE STATEMENT: This review emphasizes the practical application of G-protein-coupled receptor (GPCR) transducer knockout (KO) cells in dissecting the intricate regulatory mechanisms of the GPCR signaling network. Currently available cell lines, along with accumulating KO cell lines in diverse cell types, offer valuable resources for systematically elucidating GPCR signaling regulation. Given the association of GPCR signaling with numerous diseases, uncovering the system-based signaling map is crucial for advancing the development of novel drugs targeting specific diseases.
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Affiliation(s)
- Ayaki Saito
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Ryoji Kise
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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Tatsumi M, Cruz C, Kamakura N, Kuwabara R, Nakamura G, Ikuta T, Abrol R, Inoue A. Identification of Gα 12-vs-Gα 13-coupling determinants and development of a Gα 12/13-coupled designer GPCR. Sci Rep 2024; 14:11119. [PMID: 38750247 PMCID: PMC11096383 DOI: 10.1038/s41598-024-61506-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/07/2024] [Indexed: 05/18/2024] Open
Abstract
G-protein-coupled receptors (GPCRs) transduce diverse signals into the cell by coupling to one or several Gα subtypes. Of the 16 Gα subtypes in human cells, Gα12 and Gα13 belong to the G12 subfamily and are reported to be functionally different. Notably, certain GPCRs display selective coupling to either Gα12 or Gα13, highlighting their significance in various cellular contexts. However, the structural basis underlying this selectivity remains unclear. Here, using a Gα12-coupled designer receptor exclusively activated by designer drugs (DREADD; G12D) as a model system, we identified residues in the α5 helix and the receptor that collaboratively determine Gα12-vs-Gα13 selectivity. Residue-swapping experiments showed that G12D distinguishes differences between Gα12 and Gα13 in the positions G.H5.09 and G.H5.23 in the α5 helix. Molecular dynamics simulations observed that I378G.H5.23 in Gα12 interacts with N1032.39, S1693.53 and Y17634.53 in G12D, while H364G.H5.09 in Gα12 interact with Q2645.71 in G12D. Screening of mutations at these positions in G12D identified G12D mutants that enhanced coupling with Gα12 and to an even greater extent with Gα13. Combined mutations, most notably the dual Y17634.53H and Q2645.71R mutant, further enhanced Gα12/13 coupling, thereby serving as a potential Gα12/13-DREADD. Such novel Gα12/13-DREADD may be useful in future efforts to develop drugs that target Gα12/13 signaling as well as to identify their therapeutic indications.
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Affiliation(s)
- Manae Tatsumi
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Christian Cruz
- Department of Chemistry and Biochemistry, California State University, Northridge, CA, 91330, USA
| | - Nozomi Kamakura
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Riku Kuwabara
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Gaku Nakamura
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Tatsuya Ikuta
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Ravinder Abrol
- Department of Chemistry and Biochemistry, California State University, Northridge, CA, 91330, USA
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.
- Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-Shimo-Adachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
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Tak J, Joo MS, Kim YS, Park HW, Lee CH, Park GC, Hwang S, Kim SG. Dual regulation of NEMO by Nrf2 and miR-125a inhibits ferroptosis and protects liver from endoplasmic reticulum stress-induced injury. Theranostics 2024; 14:1841-1859. [PMID: 38505605 PMCID: PMC10945339 DOI: 10.7150/thno.89703] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 02/13/2024] [Indexed: 03/21/2024] Open
Abstract
Rationale: The surge of severe liver damage underscores the necessity for identifying new targets and therapeutic agents. Endoplasmic reticulum (ER) stress induces ferroptosis with Gα12 overexpression. NF-κB essential modulator (NEMO) is a regulator of inflammation and necroptosis. Nonetheless, the regulatory basis of NEMO de novo synthesis and its impact on hepatocyte ferroptosis need to be established. This study investigated whether Nrf2 transcriptionally induces IKBKG (the NEMO gene) for ferroptosis inhibition and, if so, how NEMO induction protects hepatocytes against ER stress-induced ferroptosis. Methods: Experiments were conducted using human liver tissues, hepatocytes, and injury models, incorporating NEMO overexpression and Gα12 gene modulations. RNA sequencing, immunoblotting, immunohistochemistry, reporter assays, and mutation analyses were done. Results: NEMO downregulation connects closely to ER and oxidative stress, worsening liver damage via hepatocyte ferroptosis. NEMO overexpression protects hepatocytes from ferroptosis by promoting glutathione peroxidase 4 (GPX4) expression. This protective role extends to oxidative and ER stress. Similar shifts occur in nuclear factor erythroid-2-related factor-2 (Nrf2) expression alongside NEMO changes. Nrf2 is newly identified as an IKBKG (NEMO gene) transactivator. Gα12 changes, apart from Nrf2, impact NEMO expression, pointing to post-transcriptional control. Gα12 reduction lowers miR-125a, an inhibitor of NEMO, while overexpression has the opposite effect. NEMO also counters ER stress, which triggers Gα12 overexpression. Gα12's significance in NEMO-dependent hepatocyte survival is confirmed via ROCK1 inhibition, a Gα12 downstream kinase, and miR-125a. The verified alterations or associations within the targeted entities are validated in human liver specimens and datasets originating from livers subjected to exposure to other injurious agents. Conclusions: Hepatic injury prompted by ER stress leads to the suppression of NEMO, thereby facilitating ferroptosis through the inhibition of GPX4. IKBKG is transactivated by Nrf2 against Gα12 overexpression responsible for the increase of miR-125a, an unprecedented NEMO inhibitor, resulting in GPX4 induction. Accordingly, the induction of NEMO mitigates ferroptotic liver injury.
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Affiliation(s)
- Jihoon Tak
- College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
- College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University-Seoul, Goyang-si, Kyeonggi-do 10326, Republic of Korea
| | - Min Sung Joo
- College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Yun Seok Kim
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hyun Woo Park
- College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Chang Hoon Lee
- College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University-Seoul, Goyang-si, Kyeonggi-do 10326, Republic of Korea
| | - Gil-Chun Park
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Shin Hwang
- Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang Geon Kim
- College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University-Seoul, Goyang-si, Kyeonggi-do 10326, Republic of Korea
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Cevheroğlu O, Demir N, Kesici MS, Özçubukçu S, Son ÇD. Downstream signalling of the disease-associated mutations on GPR56/ADGRG1. Basic Clin Pharmacol Toxicol 2023; 133:331-341. [PMID: 37056198 DOI: 10.1111/bcpt.13873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/02/2023] [Accepted: 04/01/2023] [Indexed: 04/15/2023]
Abstract
GPR56/ADGRG1 is an adhesion G protein-coupled receptor (GPCR) and mutations on this receptor cause cortical malformation due to the over-migration of neural progenitor cells on brain surface. At pial surface, GPR56 interacts with collagen III, induces Rho-dependent activation through Gα12/13 and inhibits the neuronal migration. In human glioma cells, GPR56 inhibits cell migration through Gαq/11 -dependent Rho pathway. GPR56-tetraspanin complex is known to couple Gαq/11 . GPR56 is an aGPCR that couples with various G proteins and signals through different downstream pathways. In this study, bilateral frontoparietal polymicrogyria (BFPP) mutants disrupting GPR56 function but remaining to be expressed on plasma membrane were used to study receptor signalling through Gα12 , Gα13 and Gα11 with BRET biosensors. GPR56 showed coupling with all three G proteins and activated heterotrimeric G protein signalling upon stimulation with Stachel peptide. However, BFPP mutants showed different signalling defects for each G protein indicative of distinct activation and signalling properties of GPR56 for Gα12 , Gα13 or Gα11 . β-arrestin recruitment was also investigated following the activation of GPR56 with Stachel peptide using BRET biosensors. N-terminally truncated GPR56 showed enhanced β-arrestin recruitment; however, neither wild-type receptor nor BFPP mutants gave any measurable recruitment upon Stachel stimulation, pointing different activation mechanisms for β-arrestin involvement.
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Affiliation(s)
| | - Nil Demir
- Department of Biological Sciences, Middle East Technical University, Ankara, Türkiye
| | | | - Salih Özçubukçu
- Department of Chemistry, Middle East Technical University, Ankara, Türkiye
| | - Çağdaş D Son
- Department of Biological Sciences, Middle East Technical University, Ankara, Türkiye
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10
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Goodwin AT, John AE, Joseph C, Habgood A, Tatler AL, Susztak K, Palmer M, Offermanns S, Henderson NC, Jenkins RG. Stretch regulates alveologenesis and homeostasis via mesenchymal Gαq/11-mediated TGFβ2 activation. Development 2023; 150:dev201046. [PMID: 37102682 PMCID: PMC10259661 DOI: 10.1242/dev.201046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 04/05/2023] [Indexed: 04/28/2023]
Abstract
Alveolar development and repair require tight spatiotemporal regulation of numerous signalling pathways that are influenced by chemical and mechanical stimuli. Mesenchymal cells play key roles in numerous developmental processes. Transforming growth factor-β (TGFβ) is essential for alveologenesis and lung repair, and the G protein α subunits Gαq and Gα11 (Gαq/11) transmit mechanical and chemical signals to activate TGFβ in epithelial cells. To understand the role of mesenchymal Gαq/11 in lung development, we generated constitutive (Pdgfrb-Cre+/-;Gnaqfl/fl;Gna11-/-) and inducible (Pdgfrb-Cre/ERT2+/-;Gnaqfl/fl;Gna11-/-) mesenchymal Gαq/11 deleted mice. Mice with constitutive Gαq/11 gene deletion exhibited abnormal alveolar development, with suppressed myofibroblast differentiation, altered mesenchymal cell synthetic function, and reduced lung TGFβ2 deposition, as well as kidney abnormalities. Tamoxifen-induced mesenchymal Gαq/11 gene deletion in adult mice resulted in emphysema associated with reduced TGFβ2 and elastin deposition. Cyclical mechanical stretch-induced TGFβ activation required Gαq/11 signalling and serine protease activity, but was independent of integrins, suggesting an isoform-specific role for TGFβ2 in this model. These data highlight a previously undescribed mechanism of cyclical stretch-induced Gαq/11-dependent TGFβ2 signalling in mesenchymal cells, which is imperative for normal alveologenesis and maintenance of lung homeostasis.
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Affiliation(s)
- Amanda T. Goodwin
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Nottingham NIHR Biomedical Research Centre, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Alison E. John
- Margaret Turner Warwick Centre for Fibrosing Lung Disease, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
| | - Chitra Joseph
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Nottingham NIHR Biomedical Research Centre, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Anthony Habgood
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Nottingham NIHR Biomedical Research Centre, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Amanda L. Tatler
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Nottingham NIHR Biomedical Research Centre, Nottingham, NG7 2RD, UK
- Respiratory Medicine, Biodiscovery Institute, University Park, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Katalin Susztak
- Department of Medicine, Division of Nephrology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Matthew Palmer
- Department of Pathology, Division of Nephrology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104-4238, USA
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Neil C. Henderson
- Centre for Inflammation Research, University of Edinburgh, EH16 4TJ, UK
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - R. Gisli Jenkins
- Margaret Turner Warwick Centre for Fibrosing Lung Disease, National Heart and Lung Institute, Imperial College London, London, SW3 6LY, UK
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11
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Yanagida K, Shimizu T. Lysophosphatidic acid, a simple phospholipid with myriad functions. Pharmacol Ther 2023; 246:108421. [PMID: 37080433 DOI: 10.1016/j.pharmthera.2023.108421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 04/16/2023] [Accepted: 04/17/2023] [Indexed: 04/22/2023]
Abstract
Lysophosphatidic acid (LPA) is a simple phospholipid consisting of a phosphate group, glycerol moiety, and only one hydrocarbon chain. Despite its simple chemical structure, LPA plays an important role as an essential bioactive signaling molecule via its specific six G protein-coupled receptors, LPA1-6. Recent studies, especially those using genetic tools, have revealed diverse physiological and pathological roles of LPA and LPA receptors in almost every organ system. Furthermore, many studies are illuminating detailed mechanisms to orchestrate multiple LPA receptor signaling pathways and to facilitate their coordinated function. Importantly, these extensive "bench" works are now translated into the "bedside" as exemplified by approaches targeting LPA1 signaling to combat fibrotic diseases. In this review, we discuss the physiological and pathological roles of LPA signaling and their implications for clinical application by focusing on findings revealed by in vivo studies utilizing genetic tools targeting LPA receptors.
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Affiliation(s)
- Keisuke Yanagida
- Department of Lipid Life Science, National Center for Global Health and Medicine, Tokyo, Japan.
| | - Takao Shimizu
- Department of Lipid Life Science, National Center for Global Health and Medicine, Tokyo, Japan; Institute of Microbial Chemistry, Tokyo, Japan
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12
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Bettegazzi B, Bellani S, Cattaneo S, Codazzi F, Grohovaz F, Zacchetti D. Gα13 Contributes to LPS-Induced Morphological Alterations and Affects Migration of Microglia. Mol Neurobiol 2021; 58:6397-6414. [PMID: 34529232 DOI: 10.1007/s12035-021-02553-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022]
Abstract
Microglia are the resident immune cells of the CNS that are activated in response to a variety of stimuli. This phenotypical change is aimed to maintain the local homeostasis, also by containing the insults and repair the damages. All these processes are tightly regulated and coordinated and a failure in restoring homeostasis by microglia can result in the development of neuroinflammation that can facilitate the progression of pathological conditions. Indeed, chronic microglia activation is commonly recognized as a hallmark of many neurological disorders, especially at an early stage. Many complex pathways, including cytoskeletal remodeling, are involved in the control of the microglial phenotypical and morphological changes that occur during activation. In this work, we focused on the small GTPase Gα13 and its role at the crossroad between RhoA and Rac1 signaling when microglia is exposed to pro-inflammatory stimulation. We propose the direct involvement of Gα13 in the cytoskeletal rearrangements mediated by FAK, LIMK/cofilin, and Rac1 during microglia activation. In fact, we show that Gα13 knockdown significantly inhibited LPS-induced microglial cell activation, in terms of both changes in morphology and migration, through the modulation of FAK and one of its downstream effectors, Rac1. In conclusion, we propose Gα13 as a critical factor in the regulation of morphological and functional properties of microglia during activation, which might become a target of intervention for the control of microglia inflammation.
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Affiliation(s)
- Barbara Bettegazzi
- IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
- Vita-Salute San Raffaele University, via Olgettina 58, 20132, Milan, Italy.
| | - Serena Bellani
- IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Stefano Cattaneo
- IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, via Olgettina 58, 20132, Milan, Italy
| | - Franca Codazzi
- IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, via Olgettina 58, 20132, Milan, Italy
| | - Fabio Grohovaz
- IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
- Vita-Salute San Raffaele University, via Olgettina 58, 20132, Milan, Italy
| | - Daniele Zacchetti
- IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
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13
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Critical regulation of follicular helper T cell differentiation and function by Gα 13 signaling. Proc Natl Acad Sci U S A 2021; 118:2108376118. [PMID: 34663730 PMCID: PMC8639339 DOI: 10.1073/pnas.2108376118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 12/27/2022] Open
Abstract
Optimal follicular helper T (Tfh) cell differentiation and function are required for effective humoral immunity against infection, while improper Tfh cell responses are associated with autoimmunity and allergy. We demonstrate that Gα13—a Gα protein subunit known to be involved in mediating signals related to cytoskeletal integrity, chemotaxis, and migration—acts as an essential positive regulator in Tfh cell development and function. The deletion of Gα13 in T cells results in dampened germinal center reactions in immunization and viral infection models. Mechanistically, Gα13-RhoA-ROCK2 axis is responsible for the Tfh cell differentiation from naïve precursors, and Rho agonists recuperate hampered Tfh cell function in Gα13-deficient mice. Such mechanistic insight underscores the possibility of targeting Gα13-mediated signaling to maneuver Tfh cell responses. GPCR-Gα protein–mediated signal transduction contributes to spatiotemporal interactions between immune cells to fine-tune and facilitate the process of inflammation and host protection. Beyond this, however, how Gα proteins contribute to the helper T cell subset differentiation and adaptive response have been underappreciated. Here, we found that Gα13 signaling in T cells plays a crucial role in inducing follicular helper T (Tfh) cell differentiation in vivo. T cell–specific Gα13-deficient mice have diminished Tfh cell responses in a cell-intrinsic manner in response to immunization, lymphocytic choriomeningitis virus infection, and allergen challenges. Moreover, Gα13-deficient Tfh cells express reduced levels of Bcl-6 and CXCR5 and are functionally impaired in their ability to adhere to and stimulate B cells. Mechanistically, Gα13-deficient Tfh cells harbor defective Rho-ROCK2 activation, and Rho agonist treatment recuperates Tfh cell differentiation and expression of Bcl-6 and CXCR5 in Tfh cells of T cell–specific Gα13-deficient mice. Conversely, ROCK inhibitor treatment hampers Tfh cell differentiation in wild-type mice. These findings unveil a crucial regulatory role of Gα13-Rho-ROCK axis in optimal Tfh cell differentiation and function, which might be a promising target for pharmacologic intervention in vaccine development as well as antibody-mediated immune disorders.
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14
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Rafa-Zabłocka K, Zelek-Molik A, Tepper B, Chmielarz P, Kreiner G, Wilczkowski M, Nalepa I. Chronic restraint stress induces changes in the cerebral Galpha 12/13 and Rho-GTPase signaling network. Pharmacol Rep 2021; 73:1179-1187. [PMID: 34117630 PMCID: PMC8413188 DOI: 10.1007/s43440-021-00294-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 11/24/2022]
Abstract
Background Evidence indicates that Gα12, Gα13, and its downstream effectors, RhoA and Rac1, regulate neuronal morphology affected by stress. This study was aimed at investigating whether repeated stress influences the expression of proteins related to the Gα12/13 intracellular signaling pathway in selected brain regions sensitive to the effects of stress. Furthermore, the therapeutic impact of β(1)adrenergic receptors (β1AR) blockade was assessed. Methods Restraint stress (RS) model in mice (2 h/14 days) was used to assess prolonged stress effects on the mRNA expression of Gα12, Gα13, RhoA, Rac1 in the prefrontal cortex (PFC), hippocampus (HIP) and amygdala (AMY). In a separate study, applying RS model in rats (3–4 h/1 day or 14 days), we evaluated stress effects on the expression of Gα12, Gα11, Gαq, RhoA, RhoB, RhoC, Rac1/2/3 in the HIP. Betaxolol (BET), a selective β1AR antagonist, was introduced (5 mg/kg/p.o./8–14 days) in the rat RS model to assess the role of β1AR in stress effects. RT-qPCR and Western Blot were used for mRNA and protein assessments, respectively. Results Chronic RS decreased mRNA expression of Gα12 and increased mRNA for Rac1 in the PFC of mice. In the mice AMY, decreased mRNA expression of Gα12, Gα13 and RhoA was observed. Fourteen days of RS exposure increased RhoA protein level in the rats’ HIP in the manner dependent on β1AR activity. Conclusions Together, these results suggest that repeated RS affects the expression of genes and proteins known to be engaged in neural plasticity, providing potential targets for further studies aimed at unraveling the molecular mechanisms of stress-related neuropsychiatric diseases. ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s43440-021-00294-4.
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Affiliation(s)
- Katarzyna Rafa-Zabłocka
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Agnieszka Zelek-Molik
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Beata Tepper
- Laboratory of Calcium Binding Proteins, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093, Warsaw, Poland
| | - Piotr Chmielarz
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Grzegorz Kreiner
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Michał Wilczkowski
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Irena Nalepa
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
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15
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Kim YS, Nam HJ, Han CY, Joo MS, Jang K, Jun DW, Kim SG. Liver X Receptor Alpha Activation Inhibits Autophagy and Lipophagy in Hepatocytes by Dysregulating Autophagy-Related 4B Cysteine Peptidase and Rab-8B, Reducing Mitochondrial Fuel Oxidation. Hepatology 2021; 73:1307-1326. [PMID: 32557804 DOI: 10.1002/hep.31423] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Fat accumulation results from increased fat absorption and/or defective fat metabolism. Currently, the lipid-sensing nuclear receptor that controls fat utilization in hepatocytes is elusive. Liver X receptor alpha (LXRα) promotes accumulation of lipids through the induction of several lipogenic genes. However, its effect on lipid degradation is open for study. Here, we investigated the inhibitory role of LXRα in autophagy/lipophagy in hepatocytes and the underlying basis. APPROACH AND RESULTS In LXRα knockout mice fed a high-fat diet, or cell models, LXRα activation suppressed the function of mitochondria by inhibiting autophagy/lipophagy and induced hepatic steatosis. Gene sets associated with "autophagy" were enriched in hepatic transcriptome data. Autophagy flux was markedly augmented in the LXRα knockout mouse liver and primary hepatocytes. Mechanistically, LXRα suppressed autophagy-related 4B cysteine peptidase (ATG4B) and Rab-8B, responsible for autophagosome and -lysosome formation, by inducing let-7a and microRNA (miR)-34a. Chromatin immunoprecipitation assay enabled us to find LXRα as a transcription factor of let-7a and miR-34a. Moreover, 3' untranslated region luciferase assay substantiated the direct inhibitory effects of let-7a and miR-34a on ATG4B and Rab-8B. Consistently, either LXRα activation or the let-7a/miR-34a transfection lowered mitochondrial oxygen consumption rate and mitochondrial transmembrane potential and increased fat levels. In obese animals or nonalcoholic fatty liver disease (NAFLD) patients, let-7a and miR-34a levels were elevated with simultaneous decreases in ATG4B and Rab-8B levels. CONCLUSIONS LXRα inhibits autophagy in hepatocytes through down-regulating ATG4B and Rab-8B by transcriptionally activating microRNA let-7a-2 and microRNA 34a genes and suppresses mitochondrial biogenesis and fuel consumption. This highlights a function of LXRα that culminates in the progression of liver steatosis and steatohepatitis, and the identified targets may be applied for a therapeutic strategy in the treatment of NAFLD.
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Affiliation(s)
- Yun Seok Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Hyeon Joo Nam
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Chang Yeob Han
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.,School of Pharmacy, Jeonbuk National University, Jeonju-si, Jeonbuk, Korea
| | - Min Sung Joo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Kiseok Jang
- Department of Pathology, Hanyang University School of Medicine, Seoul, Korea
| | - Dae Won Jun
- Internal Medicine, Hanyang University School of Medicine, Seoul, Korea
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
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16
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Hou L, Zhang Z, Yang L, Chang N, Zhao X, Zhou X, Yang L, Li L. NLRP3 inflammasome priming and activation in cholestatic liver injury via the sphingosine 1-phosphate/S1P receptor 2/Gα (12/13)/MAPK signaling pathway. J Mol Med (Berl) 2021; 99:273-288. [PMID: 33388881 DOI: 10.1007/s00109-020-02032-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 12/04/2020] [Accepted: 12/23/2020] [Indexed: 12/19/2022]
Abstract
NLRP3 inflammasome-driven inflammation represents a key trigger for hepatic fibrogenesis during cholestatic liver injury. However, whether sphingosine 1-phosphate (S1P) plays a role in NLRP3 inflammasome priming and activation remains unknown. Here, we found that the expression of NLRP3 in macrophages and NLRP3 inflammasome activation were significantly elevated in the liver injured by bile duct ligation (BDL). In vitro, S1P promoted the NLRP3 inflammasome priming and activation via S1P receptor 2 (S1PR2) in bone marrow-derived monocyte/macrophages (BMMs). Focusing on BMMs, the gene silencing of Gα12 or Gα13 by specific siRNA suppressed NLRP3 inflammasome priming and pro-inflammatory cytokine (IL-1β and IL-18) secretion, whereas Gα(i/o) and Gαq were not involved in this process. The MAPK signaling pathways (P38, ERK, and JNK) mediated NLRP3 inflammasome priming and IL-1β and IL-18 secretion, whereas blockage of PI3K, ROCK, and Rho family had no such effect. Moreover, JTE-013 (S1PR2 inhibitor) treatment markedly reduced NLRP3 inflammasome priming and activation in BDL-injured liver. Collectively, S1P promotes NLRP3 inflammasome priming and pro-inflammatory cytokines (IL-1β and IL-18) secretion via the S1PR2/Gα(12/13)/MAPK pathway, which may represent an effective therapeutic strategy for liver disease. KEY MESSAGE: • Hepatic NLRP3 expression was significantly elevated in BMMs of BDL-injured mouse liver. • S1P promoted NLRP3 inflammasome priming and activation in BMMs, depending on the S1PR2/Gα(12/13)/MAPK pathway. • Blockade of S1PR2 by JTE-013 reduced NLRP3 inflammasome priming and activation inflammasome in vivo.
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Affiliation(s)
- Lei Hou
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Zhi Zhang
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Le Yang
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Na Chang
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Xinhao Zhao
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Xuan Zhou
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Lin Yang
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Liying Li
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China.
- , Beijing, China.
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17
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Stecky RC, Quick CR, Fleming TL, Mull ML, Vinson VK, Whitley MS, Dover EN, Meigs TE. Divergent C-terminal motifs in Gα12 and Gα13 provide distinct mechanisms of effector binding and SRF activation. Cell Signal 2020; 72:109653. [PMID: 32330601 DOI: 10.1016/j.cellsig.2020.109653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/19/2020] [Accepted: 04/19/2020] [Indexed: 11/18/2022]
Abstract
The G12/13 subfamily of heterotrimeric guanine nucleotide binding proteins comprises the α subunits Gα12 and Gα13, which transduce signals for cell growth, cytoskeletal rearrangements, and oncogenic transformation. In an increasing range of cancers, overexpressed Gα12 or Gα13 are implicated in aberrant cell proliferation and/or metastatic invasion. Although Gα12 and Gα13 bind non-redundant sets of effector proteins and participate in unique signalling pathways, the structural features responsible for functional differences between these α subunits are largely unknown. Invertebrates encode a single G12/13 homolog that participates in cytoskeletal changes yet appears to lack signalling to SRF (serum response factor), a transcriptional activator stimulated by mammalian Gα12 and Gα13 to promote growth and tumorigenesis. Our previous studies identified an evolutionarily divergent region in Gα12 for which replacement by homologous sequence from Drosophila melanogaster abolished SRF signalling, whereas the same invertebrate substitution was fully tolerated in Gα13 [Montgomery et al. (2014) Mol. Pharmacol. 85: 586]. These findings prompted our current approach of evolution-guided mutagenesis to identify fine structural features of Gα12 and Gα13 that underlie their respective SRF activation mechanisms. Our results identified two motifs flanking the α4 helix that play a key role in Gα12 signalling to SRF. We found the region encompassing these motifs to provide an interacting surface for multiple Gα12-specific target proteins that fail to bind Gα13. Adjacent to this divergent region, a highly-conserved domain was vital for SRF activation by both Gα12 and Gα13. However, dissection of this domain using invertebrate substitutions revealed different signalling mechanisms in these α subunits and identified Gα13-specific determinants of binding Rho-specific guanine nucleotide exchange factors. Furthermore, invertebrate substitutions in the C-terminal, α5 helical region were selectively disruptive to Gα12 signalling. Taken together, our results identify key structural features near the C-terminus that evolved after the divergence of Gα12 and Gα13, and should aid the development of agents to selectively manipulate signalling by individual α subunits of the G12/13 subfamily.
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Affiliation(s)
- Rebecca C Stecky
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Courtney R Quick
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Todd L Fleming
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Makenzy L Mull
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Vanessa K Vinson
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Megan S Whitley
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - E Nicole Dover
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Thomas E Meigs
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America.
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18
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Tutunea-Fatan E, Lee JC, Denker BM, Gunaratnam L. Heterotrimeric Gα 12/13 proteins in kidney injury and disease. Am J Physiol Renal Physiol 2020; 318:F660-F672. [PMID: 31984793 DOI: 10.1152/ajprenal.00453.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Gα12 and Gα13 are ubiquitous members of the heterotrimeric guanine nucleotide-binding protein (G protein) family that play central and integrative roles in the regulation of signal transduction cascades within various cell types in the kidney. Gα12/Gα13 proteins enable the kidney to adapt to an ever-changing environment by transducing stimuli from cell surface receptors and accessory proteins to effector systems. Therefore, perturbations in Gα12/Gα13 levels or their activity can contribute to the pathogenesis of various renal diseases, including renal cancer. This review will highlight and discuss the complex and expanding roles of Gα12/Gα13 proteins on distinct renal pathologies, with emphasis on more recently reported findings. Deciphering how the different Gα12/Gα13 interaction networks participate in the onset and development of renal diseases may lead to the discovery of new therapeutic strategies.
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Affiliation(s)
- Elena Tutunea-Fatan
- Matthew Mailing Centre for Translational Transplant Studies, Lawson Health Research Institute, London, Ontario, Canada
| | - Jasper C Lee
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Bradley M Denker
- Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Lakshman Gunaratnam
- Matthew Mailing Centre for Translational Transplant Studies, Lawson Health Research Institute, London, Ontario, Canada.,Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada.,Division of Nephrology, Department of Medicine, University of Western Ontario, London, Ontario, Canada
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19
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Yanagida K, Valentine WJ. Druggable Lysophospholipid Signaling Pathways. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1274:137-176. [DOI: 10.1007/978-3-030-50621-6_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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20
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Masuho I, Skamangas NK, Martemyanov KA. Live cell optical assay for precise characterization of receptors coupling to Gα12. Basic Clin Pharmacol Toxicol 2019; 126 Suppl 6:88-95. [PMID: 30916867 DOI: 10.1111/bcpt.13228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 02/14/2019] [Indexed: 12/25/2022]
Abstract
Heterotrimeric G proteins are essential mediators of G protein-coupled receptors (GPCRs) signalling to intracellular effectors. There is a considerable diversity of G protein subunits that channel signals initiated by GPCRs into specific outcome. In particular, mammalian genomes contain 16 conserved genes encoding G protein α subunits with unique properties. Of four Gα subfamilies (Gi/o, Gq, Gs and G12/13), members of the G12/13 group have received considerable attention for their roles in carcinogenesis. However, our ability to study activation of G12/13 by GPCRs with the power to distinguish between the two subunits is limited. Here, we present an adaptation of the bioluminescence resonance energy transfer (BRET)-based assay to specifically monitor activity of Gα12 in living cells. In this kinetic assay, agonist-induced release of Venus-tagged Gβγ subunits from Gα12 is followed in real time using nano-luciferase (Nluc)-tagged BRET donor. Using this assay, we characterized bradykinin B2 receptor (BDKRB2) and found that the receptor couples to Gα12 in addition to Gαo, and Gαq, but not to Gαs. We demonstrated the utility of this assay to quantify rates of G protein activation and inactivation as well as performing dose-response studies while rank ordering signalling via individual Gα subunits. We further showed the utility of this assay to other GPCRs by demonstrating Gα12 coupling of cholecystokinin A receptor (CCKAR). Introduction of the Gα12-coupling BRET assay is expected to accelerate characterization of GPCR actions on this understudied G protein.
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Affiliation(s)
- Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, Florida
| | - Nickolas K Skamangas
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, Florida
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, Florida
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21
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Toro-Tapia G, Villaseca S, Beyer A, Roycroft A, Marcellini S, Mayor R, Torrejón M. The Ric-8A/Gα13/FAK signalling cascade controls focal adhesion formation during neural crest cell migration in Xenopus. Development 2018; 145:dev.164269. [PMID: 30297374 DOI: 10.1242/dev.164269] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 09/23/2018] [Indexed: 12/22/2022]
Abstract
Ric-8A is a pleiotropic guanine nucleotide exchange factor involved in the activation of various heterotrimeric G-protein pathways during adulthood and early development. Here, we sought to determine the downstream effectors of Ric-8A during the migration of the vertebrate cranial neural crest (NC) cells. We show that the Gα13 knockdown phenocopies the Ric-8A morphant condition, causing actin cytoskeleton alteration, protrusion instability, and a strong reduction in the number and dynamics of focal adhesions. In addition, the overexpression of Gα13 is sufficient to rescue Ric-8A-depleted cells. Ric-8A and Gα13 physically interact and colocalize in protrusions of the cells leading edge. The focal adhesion kinase FAK colocalizes and interacts with the endogenous Gα13, and a constitutively active form of Src efficiently rescues the Gα13 morphant phenotype in NC cells. We propose that Ric-8A-mediated Gα13 signalling is required for proper cranial NC cell migration by regulating focal adhesion dynamics and protrusion formation.
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Affiliation(s)
- Gabriela Toro-Tapia
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción 4030000, Chile
| | - Soraya Villaseca
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción 4030000, Chile
| | - Andrea Beyer
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción 4030000, Chile
| | - Alice Roycroft
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Sylvain Marcellini
- Departamento de Biología Cellular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción 4030000, Chile
| | - Roberto Mayor
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Marcela Torrejón
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción 4030000, Chile
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22
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Syrovatkina V, Huang XY. Signaling mechanisms and physiological functions of G-protein Gα 13 in blood vessel formation, bone homeostasis, and cancer. Protein Sci 2018; 28:305-312. [PMID: 30345641 DOI: 10.1002/pro.3531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/08/2018] [Accepted: 10/15/2018] [Indexed: 12/12/2022]
Abstract
Heterotrimeric G-proteins are cellular signal transducers. They mainly relay signals from G-protein-coupled receptors (GPCRs). GPCRs function as guanine nucleotide-exchange factors to active these G-proteins. Based on the sequence and functional similarities, these G-proteins are grouped into four subfamilies: Gs , Gi , Gq , and G12/13 . The G12/13 subfamily consists of two members: G12 and G13 . G12/13 -mediated signaling pathways play pivotal roles in a variety of physiological processes, while aberrant regulation of this pathway has been identified in various human diseases. Here we summarize the signaling mechanisms and physiological functions of Gα13 in blood vessel formation and bone homeostasis. We further discuss the expanding roles of Gα13 in cancers, serving as oncogenes as well as tumor suppressors.
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Affiliation(s)
- Viktoriya Syrovatkina
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065
| | - Xin-Yun Huang
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York, 10065
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23
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Kim TH, Yang YM, Han CY, Koo JH, Oh H, Kim SS, You BH, Choi YH, Park TS, Lee CH, Kurose H, Noureddin M, Seki E, Wan YJY, Choi CS, Kim SG. Gα12 ablation exacerbates liver steatosis and obesity by suppressing USP22/SIRT1-regulated mitochondrial respiration. J Clin Invest 2018; 128:5587-5602. [PMID: 30300140 DOI: 10.1172/jci97831] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 10/02/2018] [Indexed: 12/20/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) arises from mitochondrial dysfunction under sustained imbalance between energy intake and expenditure, but the underlying mechanisms controlling mitochondrial respiration have not been entirely understood. Heterotrimeric G proteins converge with activated GPCRs to modulate cell-signaling pathways to maintain metabolic homeostasis. Here, we investigated the regulatory role of G protein α12 (Gα12) on hepatic lipid metabolism and whole-body energy expenditure in mice. Fasting increased Gα12 levels in mouse liver. Gα12 ablation markedly augmented fasting-induced hepatic fat accumulation. cDNA microarray analysis from Gna12-KO liver revealed that the Gα12-signaling pathway regulated sirtuin 1 (SIRT1) and PPARα, which are responsible for mitochondrial respiration. Defective induction of SIRT1 upon fasting was observed in the liver of Gna12-KO mice, which was reversed by lentivirus-mediated Gα12 overexpression in hepatocytes. Mechanistically, Gα12 stabilized SIRT1 protein through transcriptional induction of ubiquitin-specific peptidase 22 (USP22) via HIF-1α increase. Gα12 levels were markedly diminished in liver biopsies from NAFLD patients. Consistently, Gna12-KO mice fed a high-fat diet displayed greater susceptibility to diet-induced liver steatosis and obesity due to decrease in energy expenditure. Our results demonstrate that Gα12 regulates SIRT1-dependent mitochondrial respiration through HIF-1α-dependent USP22 induction, identifying Gα12 as an upstream molecule that contributes to the regulation of mitochondrial energy expenditure.
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Affiliation(s)
- Tae Hyun Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
| | - Yoon Mee Yang
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea.,Division of Digestive and Liver Diseases, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Chang Yeob Han
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea.,Department of Pharmacology, School of Medicine, Wonkwang University, Iksan, Jeonbuk, South Korea
| | - Ja Hyun Koo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
| | - Hyunhee Oh
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, South Korea
| | - Su Sung Kim
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, South Korea
| | - Byoung Hoon You
- College of Pharmacy, Dongguk University, Ilsan Dong-Gu, Goyang, Gyeoggi-Do, South Korea
| | - Young Hee Choi
- College of Pharmacy, Dongguk University, Ilsan Dong-Gu, Goyang, Gyeoggi-Do, South Korea
| | - Tae-Sik Park
- Department of Life Science, Gachon University, Seongnam, Gyeonggi-Do, South Korea
| | - Chang Ho Lee
- College of Medicine, Hanyang University, Seoul, South Korea
| | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Mazen Noureddin
- Fatty Liver Disease Program, Division of Digestive and Liver Diseases, Department of Medicine, Comprehensive Transplant Center, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ekihiro Seki
- Division of Digestive and Liver Diseases, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Yu-Jui Yvonne Wan
- Department of Medical Pathology and Laboratory Medicine, UCD, Sacramento, California, USA
| | - Cheol Soo Choi
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, South Korea.,Endocrinology, Internal Medicine, Gachon University Gil Medical Center, Incheon, South Korea
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
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24
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Kim KM, Han CY, Kim JY, Cho SS, Kim YS, Koo JH, Lee JM, Lim SC, Kang KW, Kim JS, Hwang SJ, Ki SH, Kim SG. Gα 12 overexpression induced by miR-16 dysregulation contributes to liver fibrosis by promoting autophagy in hepatic stellate cells. J Hepatol 2018; 68:493-504. [PMID: 29080810 PMCID: PMC5818314 DOI: 10.1016/j.jhep.2017.10.011] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Hepatic stellate cells (HSCs) have a role in liver fibrosis. Guanine nucleotide-binding α-subunit 12 (Gα12) converges signals from G-protein-coupled receptors whose ligand levels are elevated in the environment during liver fibrosis; however, information is lacking on the effect of Gα12 on HSC trans-differentiation. This study investigated the expression of Gα12 in HSCs and the molecular basis of the effects of its expression on liver fibrosis. METHODS Gα12 expression was assessed by immunostaining, and immunoblot analyses of mouse fibrotic liver tissues and primary HSCs. The role of Gα12 in liver fibrosis was estimated using a toxicant injury mouse model with Gα12 gene knockout and/or HSC-specific Gα12 delivery using lentiviral vectors, in addition to primary HSCs and LX-2 cells using microRNA (miR) inhibitors, overexpression vectors, or adenoviruses. miR-16, Gα12, and LC3 were also examined in samples from patients with fibrosis. RESULTS Gα12 was overexpressed in activated HSCs and fibrotic liver, and was colocalised with desmin. In a carbon tetrachloride-induced fibrosis mouse model, Gα12 ablation prevented increases in fibrosis and liver injury. This effect was attenuated by HSC-specific lentiviral delivery of Gα12. Moreover, Gα12 activation promoted autophagy accompanying c-Jun N-terminal kinase-dependent ATG12-5 conjugation. In addition, miR-16 was found to be a direct inhibitor of the de novo synthesis of Gα12. Modulations of miR-16 altered autophagy in HSCs. In a fibrosis animal model or patients with severe fibrosis, miR-16 levels were lower than in their corresponding controls. Consistently, cirrhotic patient liver tissues showed Gα12 and LC3 upregulation in desmin-positive areas. CONCLUSIONS miR-16 dysregulation in HSCs results in Gα12 overexpression, which activates HSCs by facilitating autophagy through ATG12-5 formation. This suggests that Gα12 and its regulatory molecules could serve as targets for the amelioration of liver fibrosis. LAY SUMMARY Guanine nucleotide-binding α-subunit 12 (Gα12) is upregulated in activated hepatic stellate cells (HSCs) as a consequence of the dysregulation of a specific microRNA that is abundant in HSCs, facilitating the progression of liver fibrosis. This event is mediated by c-Jun N-terminal kinase-dependent ATG12-5 formation and the promotion of autophagy. We suggest that Gα12 and its associated regulators could serve as new targets in HSCs for the treatment of liver fibrosis.
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Affiliation(s)
- Kyu Min Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Chang Yeob Han
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji Young Kim
- College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea
| | - Sam Seok Cho
- College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea
| | - Yun Seok Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Ja Hyun Koo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Jung Min Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung Chul Lim
- College of Medicine, Chosun University, Gwangju 61452, Republic of Korea
| | - Keon Wook Kang
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Jae-Sung Kim
- Departments of Surgery University of Florida, Gainesville, FL 32611, USA
| | - Se Jin Hwang
- College of Medicine, Hanyang University, Seoul 04763, Republic of Korea
| | - Sung Hwan Ki
- College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea.
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25
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G-Protein Gα 13 Functions with Abl Kinase to Regulate Actin Cytoskeletal Reorganization. J Mol Biol 2017; 429:3836-3849. [PMID: 29079481 DOI: 10.1016/j.jmb.2017.10.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/17/2017] [Accepted: 10/18/2017] [Indexed: 11/23/2022]
Abstract
Heterotrimeric G-proteins are essential cellular signal transducers. One of the G-proteins, Gα13, is critical for actin cytoskeletal reorganization, cell migration, cell proliferation, and apoptosis. Previously, we have shown that Gα13 is essential for both G-protein-coupled receptor and receptor tyrosine kinase-induced actin cytoskeletal reorganization such as dynamic dorsal ruffle turnover and cell migration. However, the mechanism by which Gα13 signals to actin cytoskeletal reorganization is not completely understood. Here we show that Gα13 directly interacts with Abl tyrosine kinase, which is a critical regulator of actin cytoskeleton. This interaction is critical for Gα13-induced dorsal ruffle turnover, endothelial cell remodeling, and cell migration. Our data uncover a new molecular signaling pathway by which Gα13 controls actin cytoskeletal reorganization.
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26
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Song MK, Park C, Lee YD, Kim H, Kim MK, Kwon JO, Koo JH, Joo MS, Kim SG, Kim HH. Gα12 regulates osteoclastogenesis by modulating NFATc1 expression. J Cell Mol Med 2017; 22:849-860. [PMID: 29077264 PMCID: PMC5783869 DOI: 10.1111/jcmm.13370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 08/09/2017] [Indexed: 11/28/2022] Open
Abstract
The G12 family of G protein alpha subunits has been shown to participate in the regulation of various physiological processes. However, the role of Gα12 in bone physiology has not been well described. Here, by micro‐CT analysis, we discovered that Gα12‐knockout mice have an osteopetrotic phenotype. Histological examination showed lower osteoclast number in femoral tissue of Gα12‐knockout mice compared to wild‐type mice. Additionally, in vitro osteoclastic differentiation of precursor cells with receptor activator of nuclear factor‐κB ligand (RANKL) showed that Gα12 deficiency decreased the number of osteoclast generated and the bone resorption activity. The induction of nuclear factor of activated T‐cell c1 (NFATc1), the key transcription factor of osteoclastogenesis, and the activation of RhoA by RANKL was also significantly suppressed by Gα12 deficiency. We further found that the RANKL induction of NFATc1 was not dependent on RhoA signalling, while osteoclast precursor migration and bone resorption required RhoA in the Gα12‐mediated regulation of osteoclasts. Therefore, Gα12 plays a role in differentiation through NFATc1 and in cell migration and resorption activity through RhoA during osteoclastogenesis.
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Affiliation(s)
- Min-Kyoung Song
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Cheolkyu Park
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Yong Deok Lee
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Haemin Kim
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Min Kyung Kim
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Jun-Oh Kwon
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Ja Hyun Koo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Min Sung Joo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Hong-Hee Kim
- Department of Cell and Developmental Biology, BK21 Program and Dental Research Institute, Seoul National University, Seoul, Korea
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27
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Ko SH, Choi GE, Oh JY, Lee HJ, Kim JS, Chae CW, Choi D, Han HJ. Succinate promotes stem cell migration through the GPR91-dependent regulation of DRP1-mediated mitochondrial fission. Sci Rep 2017; 7:12582. [PMID: 28974722 PMCID: PMC5626702 DOI: 10.1038/s41598-017-12692-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/13/2017] [Indexed: 12/24/2022] Open
Abstract
The role of metabolites produced from stem cell metabolism has been emerged as signaling molecules to regulate stem cell behaviors such as migration. The mitochondrial morphology is closely associated with the metabolic balance and stem cell function. However, the physiological role of succinate on human mesenchymal stem cell (hMSC) migration by regulating the mitochondrial morphology remains unclear. Here, we investigate the effect of succinate on hMSC migration via regulation of mitochondrial dynamics and its related signaling pathway. Succinate (50 μM) significantly accelerates hMSC migration. Succinate increases phosphorylation of pan-PKC, especially the atypical PKCζ level which was blocked by the knockdown of Gαq and Gα12. Activated PKCζ subsequently phosphorylates p38 MAPK. Cytosolic DRP1 is phosphorylated by p38 MAPK and results in DRP1 translocation to the mitochondria outer membrane, eventually inducing mitochondrial fragmentation. Mitochondrial fission-induced mitochondrial function elevates mitochondrial ROS (mtROS) levels and activates Rho GTPases, which then induces F-actin formation. Furthermore, in a skin excisional wound model, we found the effects of succinate-pretreated hMSC enhanced wound closure, vascularization and re-epithelialization and confirmed that DRP1 has a vital role in injured tissue regeneration. Overall, succinate promotes DRP1-mediated mitochondrial fission via GPR91, consequently stimulating the hMSC migration through mtROS-induced F-actin formation.
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Affiliation(s)
- So Hee Ko
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS program for Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea
| | - Gee Euhn Choi
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS program for Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea
| | - Ji Young Oh
- Department of Agricultural Biotechnology, Animal Biotechnology Major, and Research Institute for Agriculture and Life science, Seoul National University, Seoul, 08826, South Korea
| | - Hyun Jik Lee
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS program for Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea
| | - Jun Sung Kim
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS program for Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea
| | - Chang Woo Chae
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS program for Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea
| | - Diana Choi
- Department of Biological Sciences, Mount Holyoke College, South Hadley, Massachusetts, 01075, USA
| | - Ho Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine, Research Institute for Veterinary Science, and BK21 PLUS program for Creative Veterinary Research Center, Seoul National University, Seoul, 08826, South Korea.
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28
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Role of G Protein-Coupled Receptors in the Regulation of Structural Plasticity and Cognitive Function. Molecules 2017; 22:molecules22071239. [PMID: 28737723 PMCID: PMC6152405 DOI: 10.3390/molecules22071239] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 07/14/2017] [Indexed: 12/26/2022] Open
Abstract
Cognition and other higher brain functions are known to be intricately associated with the capacity of neural circuits to undergo structural reorganization. Structural remodelling of neural circuits, or structural plasticity, in the hippocampus plays a major role in learning and memory. Dynamic modifications of neuronal connectivity in the form of dendritic spine morphology alteration, as well as synapse formation and elimination, often result in the strengthening or weakening of specific neural circuits that determine synaptic plasticity. Changes in dendritic complexity and synapse number are mediated by cellular processes that are regulated by extracellular signals such as neurotransmitters and neurotrophic factors. As many neurotransmitters act on G protein-coupled receptors (GPCRs), it has become increasingly apparent that GPCRs can regulate structural plasticity through a myriad of G protein-dependent pathways and non-canonical signals. A thorough understanding of how GPCRs exert their regulatory influence on dendritic spine morphogenesis may provide new insights for treating cognitive impairment and decline in various age-related diseases. In this article, we review the evidence of GPCR-mediated regulation of structural plasticity, with a special emphasis on the involvement of common as well as distinct signalling pathways that are regulated by major neurotransmitters.
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29
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Yu AC, Zambrano RM, Cristian I, Price S, Bernhard B, Zucker M, Venkateswaran S, McGowan-Jordan J, Armour CM. Variable developmental delays and characteristic facial features-A novel 7p22.3p22.2 microdeletion syndrome? Am J Med Genet A 2017; 173:1593-1600. [PMID: 28440577 DOI: 10.1002/ajmg.a.38241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 03/08/2017] [Accepted: 03/11/2017] [Indexed: 12/22/2022]
Abstract
Isolated 7p22.3p22.2 deletions are rarely described with only two reports in the literature. Most other reported cases either involve a much larger region of the 7p arm or have an additional copy number variation. Here, we report five patients with overlapping microdeletions at 7p22.3p22.2. The patients presented with variable developmental delays, exhibiting relative weaknesses in expressive language skills and relative strengths in gross, and fine motor skills. The most consistent facial features seen in these patients included a broad nasal root, a prominent forehead a prominent glabella and arched eyebrows. Additional variable features amongst the patients included microcephaly, metopic ridging or craniosynostosis, cleft palate, cardiac defects, and mild hypotonia. Although the patients' deletions varied in size, there was a 0.47 Mb region of overlap which contained 7 OMIM genes: EIP3B, CHST12, LFNG, BRAT1, TTYH3, AMZ1, and GNA12. We propose that monosomy of this region represents a novel microdeletion syndrome. We recommend that individuals with 7p22.3p22.2 deletions should receive a developmental assessment and a thorough cardiac exam, with consideration of an echocardiogram, as part of their initial evaluation.
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Affiliation(s)
- Andrea C Yu
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Regina M Zambrano
- Division of Clinical Genetics, Department of Pediatrics, Louisiana State University Health Science Center, New Orleans, Louisiana
| | - Ingrid Cristian
- Division of Genetics and Metabolism, Department of Pediatrics, Nemours Children's Hospital Orlando, Orlando, Florida
| | - Sue Price
- Oxford Regional Genetic Service, Churchill Hospital, Oxford, UK
| | - Birgitta Bernhard
- North West Thames Regional Genetic Service, North West London Hospitals, Greater London, England
| | - Marc Zucker
- Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Sunita Venkateswaran
- Division of Neurology, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Jean McGowan-Jordan
- Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Christine M Armour
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada.,Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
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30
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Yung BS, Brand CS, Xiang SY, Gray CBB, Means CK, Rosen H, Chun J, Purcell NH, Brown JH, Miyamoto S. Selective coupling of the S1P 3 receptor subtype to S1P-mediated RhoA activation and cardioprotection. J Mol Cell Cardiol 2017; 103:1-10. [PMID: 28017639 PMCID: PMC5410967 DOI: 10.1016/j.yjmcc.2016.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 01/17/2023]
Abstract
Sphingosine-1-phosphate (S1P), a bioactive lysophospholipid, is generated and released at sites of tissue injury in the heart and can act on S1P1, S1P2, and S1P3 receptor subtypes to affect cardiovascular responses. We established that S1P causes little phosphoinositide hydrolysis and does not induce hypertrophy indicating that it does not cause receptor coupling to Gq. We previously demonstrated that S1P confers cardioprotection against ischemia/reperfusion by activating RhoA and its downstream effector PKD. The S1P receptor subtypes and G proteins that regulate RhoA activation and downstream responses in the heart have not been determined. Using siRNA or pertussis toxin to inhibit different G proteins in NRVMs we established that S1P regulates RhoA activation through Gα13 but not Gα12, Gαq, or Gαi. Knockdown of the three major S1P receptors using siRNA demonstrated a requirement for S1P3 in RhoA activation and subsequent phosphorylation of PKD, and this was confirmed in studies using isolated hearts from S1P3 knockout (KO) mice. S1P treatment reduced infarct size induced by ischemia/reperfusion in Langendorff perfused wild-type (WT) hearts and this protection was abolished in the S1P3 KO mouse heart. CYM-51736, an S1P3-specific agonist, also decreased infarct size after ischemia/reperfusion to a degree similar to that achieved by S1P. The finding that S1P3 receptor- and Gα13-mediated RhoA activation is responsible for protection against ischemia/reperfusion suggests that selective targeting of S1P3 receptors could provide therapeutic benefits in ischemic heart disease.
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Affiliation(s)
- Bryan S Yung
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Cameron S Brand
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Sunny Y Xiang
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Charles B B Gray
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | | | - Hugh Rosen
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037, United States
| | - Jerold Chun
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, Scripps Research Institute, La Jolla, CA 92037, United States
| | - Nicole H Purcell
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Joan Heller Brown
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
| | - Shigeki Miyamoto
- Department of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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31
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John AE, Wilson MR, Habgood A, Porte J, Tatler AL, Stavrou A, Miele G, Jolly L, Knox AJ, Takata M, Offermanns S, Jenkins RG. Loss of epithelial Gq and G11 signaling inhibits TGFβ production but promotes IL-33-mediated macrophage polarization and emphysema. Sci Signal 2016; 9:ra104. [PMID: 27811142 DOI: 10.1126/scisignal.aad5568] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heterotrimeric guanine nucleotide-binding protein (G protein) signaling links hundreds of G protein-coupled receptors with four G protein signaling pathways. Two of these, one mediated by Gq and G11 (Gq/11) and the other by G12 and G13 (G12/13), are implicated in the force-dependent activation of transforming growth factor-β (TGFβ) in lung epithelial cells. Reduced TGFβ activation in alveolar cells leads to emphysema, whereas enhanced TGFβ activation promotes acute lung injury and idiopathic pulmonary fibrosis. Therefore, precise control of alveolar TGFβ activation is essential for alveolar homeostasis. We investigated the involvement of the Gq/11 and G12/13 pathways in epithelial cells in generating active TGFβ and regulating alveolar inflammation. Mice deficient in both Gαq and Gα11 developed inflammation that was primarily caused by alternatively activated (M2-polarized) macrophages, enhanced matrix metalloproteinase 12 (MMP12) production, and age-related alveolar airspace enlargement consistent with emphysema. Mice with impaired Gq/11 signaling had reduced stretch-mediated generation of TGFβ by epithelial cells and enhanced macrophage MMP12 synthesis but were protected from the effects of ventilator-induced lung injury. Furthermore, synthesis of the cytokine interleukin-33 (IL-33) was increased in these alveolar epithelial cells, resulting in the M2-type polarization of alveolar macrophages independently of the effect on TGFβ. Our results suggest that alveolar Gq/11 signaling maintains alveolar homeostasis and likely independently increases TGFβ activation in response to the mechanical stress of the epithelium and decreases epithelial IL-33 synthesis. Together, these findings suggest that disruption of Gq/11 signaling promotes inflammatory emphysema but protects against mechanically induced lung injury.
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Affiliation(s)
- Alison E John
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K.
| | - Michael R Wilson
- Department of Anaesthetics, Pain Medicine and Intensive Care, Imperial College, London, U.K
| | - Anthony Habgood
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
| | - Joanne Porte
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
| | - Amanda L Tatler
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
| | - Anastasios Stavrou
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
| | | | - Lisa Jolly
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
| | - Alan J Knox
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
| | - Masao Takata
- Department of Anaesthetics, Pain Medicine and Intensive Care, Imperial College, London, U.K
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - R Gisli Jenkins
- Division of Respiratory Medicine, University of Nottingham, Nottingham, U.K
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Syrovatkina V, Alegre KO, Dey R, Huang XY. Regulation, Signaling, and Physiological Functions of G-Proteins. J Mol Biol 2016; 428:3850-68. [PMID: 27515397 DOI: 10.1016/j.jmb.2016.08.002] [Citation(s) in RCA: 265] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 07/31/2016] [Accepted: 08/03/2016] [Indexed: 12/31/2022]
Abstract
Heterotrimeric guanine-nucleotide-binding regulatory proteins (G-proteins) mainly relay the information from G-protein-coupled receptors (GPCRs) on the plasma membrane to the inside of cells to regulate various biochemical functions. Depending on the targeted cell types, tissues, and organs, these signals modulate diverse physiological functions. The basic schemes of heterotrimeric G-proteins have been outlined. In this review, we briefly summarize what is known about the regulation, signaling, and physiological functions of G-proteins. We then focus on a few less explored areas such as the regulation of G-proteins by non-GPCRs and the physiological functions of G-proteins that cannot be easily explained by the known G-protein signaling pathways. There are new signaling pathways and physiological functions for G-proteins to be discovered and further interrogated. With the advancements in structural and computational biological techniques, we are closer to having a better understanding of how G-proteins are regulated and of the specificity of G-protein interactions with their regulators.
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Affiliation(s)
- Viktoriya Syrovatkina
- Department of Physiology and Biophysics, Weill Cornell Medical College, of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Kamela O Alegre
- Department of Physiology and Biophysics, Weill Cornell Medical College, of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Raja Dey
- Department of Physiology and Biophysics, Weill Cornell Medical College, of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Xin-Yun Huang
- Department of Physiology and Biophysics, Weill Cornell Medical College, of Cornell University, 1300 York Avenue, New York, NY 10065, USA.
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Wu Y, Xu JX, El-Jouni W, Lu T, Li S, Wang Q, Tran M, Yu W, Wu M, Barrera IE, Bonventre JV, Zhou J, Denker BM, Kong T. Gα12 is required for renal cystogenesis induced by Pkd1 inactivation. J Cell Sci 2016; 129:3675-3684. [PMID: 27505895 DOI: 10.1242/jcs.190496] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/21/2016] [Indexed: 01/09/2023] Open
Abstract
Mutation of PKD1, encoding the protein polycystin-1 (PC1), is the main cause of autosomal dominant polycystic kidney disease (ADPKD). The signaling pathways downstream of PC1 in ADPKD are still not fully understood. Here, we provide genetic evidence for the necessity of Gα12 (encoded by Gna12, hereafter Gα12) for renal cystogenesis induced by Pkd1 knockout. There was no phenotype in mice with deletion of Gα12 (Gα12-/-). Polyinosine-polycytosine (pI:pC)-induced deletion of Pkd1 (Mx1Cre+Pkd1f/fGα12+/+) in 1-week-old mice resulted in multiple kidney cysts by 9 weeks, but the mice with double knockout of Pkd1 and Gα12 (Mx1Cre+Pkd1f/fGα12-/-) had no structural and functional abnormalities in the kidneys. These mice could survive more than one year without kidney abnormalities except multiple hepatic cysts in some mice, which indicates that the effect of Gα12 on cystogenesis is kidney specific. Furthermore, Pkd1 knockout promoted Gα12 activation, which subsequently decreased cell-matrix and cell-cell adhesion by affecting the function of focal adhesion and E-cadherin, respectively. Our results demonstrate that Gα12 is required for the development of kidney cysts induced by Pkd1 mutation in mouse ADPKD.
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Affiliation(s)
- Yong Wu
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jen X Xu
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Wassim El-Jouni
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Tzongshi Lu
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Suyan Li
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Qingyi Wang
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mei Tran
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA Renal Division, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Wanfeng Yu
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Maoqing Wu
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ivan E Barrera
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Joseph V Bonventre
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jing Zhou
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bradley M Denker
- Renal Division, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Tianqing Kong
- Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Xu JX, Lu TS, Li S, Wu Y, Ding L, Denker BM, Bonventre JV, Kong T. Polycystin-1 and Gα12 regulate the cleavage of E-cadherin in kidney epithelial cells. Physiol Genomics 2014; 47:24-32. [PMID: 25492927 DOI: 10.1152/physiolgenomics.00090.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Interaction of polycystin-1 (PC1) and Gα12 is important for development of kidney cysts in autosomal dominant polycystic kidney disease (ADPKD). The integrity of cell polarity and cell-cell adhesions (mainly E-cadherin-mediated adherens junction) is altered in the renal epithelial cells of ADPKD. However, the key signaling pathway for this alteration is not fully understood. Madin-Darby canine kidney (MDCK) cells maintain the normal integrity of epithelial cell polarity and adherens junctions. Here, we found that deletion of Pkd1 increased activation of Gα12, which then promoted the cystogenesis of MDCK cells. The morphology of these cells was altered after the activation of Gα12. By using liquid chromatography-mass spectrometry, we found several proteins that could be related this change in the extracellular milieu. E-cadherin was one of the most abundant peptides after active Gα12 was induced. Gα12 activation or Pkd1 deletion increased the shedding of E-cadherin, which was mediated via increased ADAM10 activity. The increased shedding of E-cadherin was blocked by knockdown of ADAM10 or specific ADAM10 inhibitor GI254023X. Pkd1 deletion or Gα12 activation also changed the distribution of E-cadherin in kidney epithelial cells and caused β-catenin to shift from cell membrane to nucleus. Finally, ADAM10 inhibitor, GI254023X, blocked the cystogenesis induced by PC1 knockdown or Gα12 activation in renal epithelial cells. Our results demonstrate that the E-cadherin/β-catenin signaling pathway is regulated by PC1 and Gα12 via ADAM10. Specific inhibition of this pathway, especially ADAM10 activity, could be a novel therapeutic regimen for ADPKD.
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Affiliation(s)
- Jen X Xu
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Tzong-Shi Lu
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Suyan Li
- Division of Basic Neuroscience, McLean Hospital, Belmont, Massachusetts
| | - Yong Wu
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Lai Ding
- Harvard NeuroDiscovery Center, Boston, Massachusetts; and
| | - Bradley M Denker
- Beth Israel Deaconess Medical Center, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts
| | - Joseph V Bonventre
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Tianqing Kong
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts;
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Gα12 gep oncogene deregulation of p53-responsive microRNAs promotes epithelial-mesenchymal transition of hepatocellular carcinoma. Oncogene 2014; 34:2910-21. [PMID: 25065598 DOI: 10.1038/onc.2014.218] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 06/12/2014] [Accepted: 06/15/2014] [Indexed: 11/09/2022]
Abstract
Hepatocellular carcinoma (HCC) has a poor prognosis owing to aggressive phenotype. Gα12 gep oncogene product couples to G-protein-coupled receptors, whose ligand levels are frequently increased in tumor microenvironments. Here, we report Gα12 overexpression in human HCC and the resultant induction of zinc-finger E-box-binding homeobox 1 (ZEB1) as mediated by microRNA deregulation. Gα12 expression was higher in HCC than surrounding non-tumorous tissue. Transfection of Huh7 cell with an activated mutant of Gα12 (Gα12QL) deregulated microRNA (miRNA or miR)-200b/a/429, -194-2/192 and -194-1/215 clusters in the miRNome. cDNA microarray analyses disclosed the targets affected by Gα12 gene knockout. An integrative network of miRNAs and mRNA changes enabled us to predict ZEB1 as a key molecule governed by Gα12. Decreases of miR-200a/b, -192 and -215 by Gα12 caused ZEB1 induction. The ability of Gα12 to decrease p53 levels, as a result of activating protein-1 (AP-1)/c-Jun-mediated mouse double minute 2 homolog induction, contributed to transcriptional deregulation of the miRNAs. Gα12QL induced ZEB1 and other epithelial-mesenchymal transition markers with fibroblastoid phenotype change. Consistently, transfection with miR-200b, -192 or -215 mimic prevented the ability of Gα12QL to increase tumor cell migration/invasion. In xenograft studies, sustained knockdown of Gα12 decreased the overall growth rate and average volume of tumors derived from SK-Hep1 cell (mesenchymal-typed). In HCC patients, miR-192, -215 and/or -200a were deregulated with microvascular invasion or growth advantage. In the HCC samples with higher Gα12 level, a correlation existed in the comparison of relative changes of Gα12 and ZEB1. In conclusion, Gα12 overexpressed in HCC causes ZEB1 induction by deregulating p53-responsive miRNAs, which may facilitate epithelial-mesenchymal transition and growth of liver tumor. These findings highlight the significance of Gα12 upregulation in liver tumor progression, implicating Gα12 as an attractive therapeutic target.
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Bartolomé RA, Díaz-Martínez M, Coló GP, Arellano-Sánchez N, Torres-Ayuso P, Kleinovink JW, Mérida I, Teixidó J. A Blk-p190RhoGAP signaling module downstream of activated Gα13 functionally opposes CXCL12-stimulated RhoA activation and cell invasion. Cell Signal 2014; 26:2551-61. [PMID: 25025568 DOI: 10.1016/j.cellsig.2014.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 11/27/2022]
Abstract
Activation of the GTPase RhoA linked to cell invasion can be tightly regulated following Gα13 stimulation. We have used a cellular model displaying Gα13-dependent inhibition of RhoA activation associated with defective cell invasion to the chemokine CXCL12 to characterize the molecular players regulating these processes. Using both RNAi transfection approaches and protein overexpression experiments here we show that the Src kinase Blk is involved in Gα13-activated tyrosine phosphorylation of p190RhoGAP, which causes RhoA inactivation and ultimately leads to deficient cell invasion. Characterization of molecular interplays between Gα13, Blk and p190RhoGAP revealed that Blk binds Gα13, and that Blk-mediated p190RhoGAP phosphorylation upon Gα13 activation correlates with weakening of Gα13-Blk association connected to increased Blk-p190RhoGAP assembly. These results place Blk upstream of the p190RhoGAP-RhoA pathway in Gα13-activated cells, overall representing an opposing signaling module during CXCL12-triggered invasion. In addition, analyses with Blk- or Gα13-knockdown cells indicated that Blk can also mediate CXCL12-triggered phosphorylation of p190RhoGAP independently of Gα13. However, even if CXCL12 induces the Blk-mediated GAP phosphorylation, the simultaneous stimulation of the guanine-nucleotide exchange factor Vav1 by the chemokine, as earlier reported, leads to a net increase in RhoA activation. Therefore, when Gα13 is concurrently stimulated with CXCL12 there appears to be sufficient Blk activity to promote adequate levels of p190RhoGAP tyrosine phosphorylation to inactivate RhoA and to impair cell invasiveness.
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Affiliation(s)
- Rubén A Bartolomé
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain
| | - Marta Díaz-Martínez
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain
| | - Georgina P Coló
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain
| | - Nohemí Arellano-Sánchez
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain
| | - Pedro Torres-Ayuso
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CSIC), 28049 Madrid, Spain
| | - Jan Willem Kleinovink
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain
| | - Isabel Mérida
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CSIC), 28049 Madrid, Spain
| | - Joaquin Teixidó
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain.
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G-protein stimulatory subunit alpha and Gq/11α G-proteins are both required to maintain quiescent stem-like chondrocytes. Nat Commun 2014; 5:3673. [PMID: 24781502 DOI: 10.1038/ncomms4673] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/17/2014] [Indexed: 12/21/2022] Open
Abstract
Round chondrocytes in the resting zone of the growth plate provide precursors for columnar chondrocytes and have stem-like properties. Here we demonstrate that these stem-like chondrocytes undergo apoptosis in the absence of the receptor (PPR) for parathyroid hormone-related protein. We examine the possible roles of heterotrimeric G-proteins activated by the PPR. Inactivation of the G-protein stimulatory α-subunit (G(s)α) leads to accelerated differentiation of columnar chondrocytes, as seen in the PPR knockout, but a remnant of growth cartilage remains, in contrast to disappearance of the growth cartilage in the PPR knockout. Stem-like chondrocytes lose their quiescence and proliferate upon G(s)α ablation. Inactivation of G(s)α in mice with a mutant PPR that cannot activate G proteins, Gq and G11, leads to a PPR knockout-like phenotype. Thus, G(s)α is the major mediator of the anti-differentiation action of the PPR, while activation of both G(s)α and Gq/11α is required for quiescence of stem-like chondrocytes.
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Montgomery ER, Temple BRS, Peters KA, Tolbert CE, Booker BK, Martin JW, Hamilton TP, Tagliatela AC, Smolski WC, Rogers SL, Jones AM, Meigs TE. Gα12 structural determinants of Hsp90 interaction are necessary for serum response element-mediated transcriptional activation. Mol Pharmacol 2014; 85:586-97. [PMID: 24435554 PMCID: PMC3965892 DOI: 10.1124/mol.113.088443] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 01/16/2014] [Indexed: 12/31/2022] Open
Abstract
The G12/13 class of heterotrimeric G proteins, comprising the α-subunits Gα12 and Gα13, regulates multiple aspects of cellular behavior, including proliferation and cytoskeletal rearrangements. Although guanine nucleotide exchange factors for the monomeric G protein Rho (RhoGEFs) are well characterized as effectors of this G protein class, a variety of other downstream targets has been reported. To identify Gα12 determinants that mediate specific protein interactions, we used a structural and evolutionary comparison between the G12/13, Gs, Gi, and Gq classes to identify "class-distinctive" residues in Gα12 and Gα13. Mutation of these residues in Gα12 to their deduced ancestral forms revealed a subset necessary for activation of serum response element (SRE)-mediated transcription, a G12/13-stimulated pathway implicated in cell proliferative signaling. Unexpectedly, this subset of Gα12 mutants showed impaired binding to heat-shock protein 90 (Hsp90) while retaining binding to RhoGEFs. Corresponding mutants of Gα13 exhibited robust SRE activation, suggesting a Gα12-specific mechanism, and inhibition of Hsp90 by geldanamycin or small interfering RNA-mediated lowering of Hsp90 levels resulted in greater downregulation of Gα12 than Gα13 signaling in SRE activation experiments. Furthermore, the Drosophila G12/13 homolog Concertina was unable to signal to SRE in mammalian cells, and Gα12:Concertina chimeras revealed Gα12-specific determinants of SRE activation within the switch regions and a C-terminal region. These findings identify Gα12 determinants of SRE activation, implicate Gα12:Hsp90 interaction in this signaling mechanism, and illuminate structural features that arose during evolution of Gα12 and Gα13 to allow bifurcated mechanisms of signaling to a common cell proliferative pathway.
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Affiliation(s)
- Ellyn R Montgomery
- Department of Biology, University of North Carolina at Asheville, Asheville, North Carolina (E.R.M., B.K.B., J.W.M., T.P.H., A.C.T., W.C.S., T.E.M.); Departments of Biology (K.A.P., S.L.R., A.M.J.), Biochemistry and Biophysics (B.R.S.T.), Cell Biology and Physiology (C.E.T.), and Pharmacology (A.M.J.), R. L. Juliano Structural Bioinformatics Core Facility (B.R.S.T.), and Carolina Center for Genome Sciences (S.L.R.), University of North Carolina, and the Lineberger Comprehensive Cancer Center, (S.L.R., T.E.M.), Chapel Hill, North Carolina
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Xing B, Wang L, Guo D, Huang J, Espenel C, Kreitzer G, Zhang JJ, Guo L, Huang XY. Atypical protein kinase Cλ is critical for growth factor receptor-induced dorsal ruffle turnover and cell migration. J Biol Chem 2013; 288:32827-36. [PMID: 24092753 DOI: 10.1074/jbc.m113.489427] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Gα13, a member of the heterotrimeric G proteins, is critical for actin cytoskeletal reorganization and cell migration. Previously we have shown that Gα13 is essential for both G protein-coupled receptor and receptor tyrosine kinase-induced actin cytoskeletal reorganization such as dynamic dorsal ruffle turnover and cell migration. Ric-8A, a non-receptor guanine nucleotide exchange factor for some heterotrimeric G proteins, is critical for coupling receptor tyrosine kinases to Gα13. Here, we show that PDGF can induce phosphorylation of Ric-8A. Atypical protein kinase Cλ (aPKCλ) is required for Ric-8A phosphorylation. Furthermore, aPKCλ is required for PDGF-induced dorsal ruffle turnover and cell migration as demonstrated by both down-regulation of aPKCλ protein levels in cells by RNA interference and by studies in aPKCλ knock-out cells. Moreover, phosphorylation of Ric-8A modulates its subcellular localization. Hence, aPKCλ is critical for PDGF-induced actin cytoskeletal reorganization and cell migration.
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Affiliation(s)
- Bowen Xing
- From the College of Life Sciences, Wuhan University, Wuhan 430072, China, and
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Abstract
OBJECTIVES Tumor microenvironment, defined by a variety of growth factors including lysophosphatidic acid (LPA), whose levels are increased in pancreatic cancer patients, plays a major role in the genesis and progression of pancreatic cancer. Because the gep proto-oncogenes, Gα12 and Gα13, are implicated in LPA-stimulated oncogenic signaling, this study is focused on evaluating the role of these proto-oncogenes in LPA-stimulated invasive migration of pancreatic cancer cells. METHODS Effect of LPA on the migration and proliferation of pancreatic cancer cells was assessed using BxPC3, Dan-G, MDAPanc-28, Panc-1, and PaCa-2 cell lines. The role of Gα13 in the migration of pancreatic cancer cells was interrogated by disrupting lysophosphatidic acid receptor-Gα13 interaction using CT13, a dominant negative mutant of Gα13, and by silencing the expression of Gα13. RESULTS Results indicate that LPA stimulates the migration of pancreatic cancer cells and such LPA-stimulated migratory response is mediated by Gα13. Furthermore, the results establish that the silencing of Gα13, but not Gα12, abrogates LPA-stimulated invasive migration of pancreatic cancer cells. CONCLUSIONS These results report for the first time a critical role for Gα13 in LPA-stimulated invasive migration of pancreatic cancer cells. These findings identify LPA-lysophosphatidic acid receptor-Gα13 signaling node as a novel therapeutic target for pancreatic cancer treatment and control.
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Spindler MJ, Burmeister BT, Huang Y, Hsiao EC, Salomonis N, Scott MJ, Srivastava D, Carnegie GK, Conklin BR. AKAP13 Rho-GEF and PKD-binding domain deficient mice develop normally but have an abnormal response to β-adrenergic-induced cardiac hypertrophy. PLoS One 2013; 8:e62705. [PMID: 23658642 PMCID: PMC3637253 DOI: 10.1371/journal.pone.0062705] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 03/28/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND A-kinase anchoring proteins (AKAPs) are scaffolding molecules that coordinate and integrate G-protein signaling events to regulate development, physiology, and disease. One family member, AKAP13, encodes for multiple protein isoforms that contain binding sites for protein kinase A (PKA) and D (PKD) and an active Rho-guanine nucleotide exchange factor (Rho-GEF) domain. In mice, AKAP13 is required for development as null embryos die by embryonic day 10.5 with cardiovascular phenotypes. Additionally, the AKAP13 Rho-GEF and PKD-binding domains mediate cardiomyocyte hypertrophy in cell culture. However, the requirements for the Rho-GEF and PKD-binding domains during development and cardiac hypertrophy are unknown. METHODOLOGY/PRINCIPAL FINDINGS To determine if these AKAP13 protein domains are required for development, we used gene-trap events to create mutant mice that lacked the Rho-GEF and/or the protein kinase D-binding domains. Surprisingly, heterozygous matings produced mutant mice at Mendelian ratios that had normal viability and fertility. The adult mutant mice also had normal cardiac structure and electrocardiograms. To determine the role of these domains during β-adrenergic-induced cardiac hypertrophy, we stressed the mice with isoproterenol. We found that heart size was increased similarly in mice lacking the Rho-GEF and PKD-binding domains and wild-type controls. However, the mutant hearts had abnormal cardiac contractility as measured by fractional shortening and ejection fraction. CONCLUSIONS These results indicate that the Rho-GEF and PKD-binding domains of AKAP13 are not required for mouse development, normal cardiac architecture, or β-adrenergic-induced cardiac hypertrophic remodeling. However, these domains regulate aspects of β-adrenergic-induced cardiac hypertrophy.
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Affiliation(s)
- Matthew J Spindler
- Gladstone Institute of Cardiovascular Disease, San Francisco, California, USA.
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Wang Y, Li Y, Shi G. The regulating function of heterotrimeric G proteins in the immune system. Arch Immunol Ther Exp (Warsz) 2013; 61:309-19. [PMID: 23563866 DOI: 10.1007/s00005-013-0230-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 03/25/2013] [Indexed: 01/17/2023]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins), which consist of an α-, a β- and a γ-subunit, have crucial roles as molecular switches in the regulation of the downstream effector molecules of multiple G protein-coupled receptor signalling pathways, such as phospholipase C and adenylyl cyclase. According to the structural and functional similarities of their α-subunits, G proteins can be divided into four subfamilies: Gαs, Gαi/o, Gαq/11 and Gα12/13. Most of the α- and the βγ-subunits are abundantly expressed on the surface of immune cells. Recent studies have demonstrated that G proteins are a group of important immunomodulatory factors that regulate the migration, activation, survival, proliferation, differentiation and cytokine secretion of immune cells. In this review, we summarise the recent findings on the functions of G proteins in immune regulation and autoimmunity.
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Affiliation(s)
- Yantang Wang
- Department of Immunology, Chengdu Medical College, Chengdu, China
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Ritchie BJ, Smolski WC, Montgomery ER, Fisher ES, Choi TY, Olson CM, Foster LA, Meigs TE. Determinants at the N- and C-termini of Gα12 required for activation of Rho-mediated signaling. J Mol Signal 2013; 8:3. [PMID: 23531275 PMCID: PMC3636079 DOI: 10.1186/1750-2187-8-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/17/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heterotrimeric guanine nucleotide binding proteins of the G12/13 subfamily, which includes the α-subunits Gα12 and Gα13, stimulate the monomeric G protein RhoA through interaction with a distinct subset of Rho-specific guanine nucleotide exchange factors (RhoGEFs). The structural features that mediate interaction between Gα13 and RhoGEFs have been examined in crystallographic studies of the purified complex, whereas a Gα12:RhoGEF complex has not been reported. Several signaling responses and effector interactions appear unique to Gα12 or Gα13, despite their similarity in amino acid sequence. METHODS To comprehensively examine Gα12 for regions involved in RhoGEF interaction, we screened a panel of Gα12 cassette substitution mutants for binding to leukemia-associated RhoGEF (LARG) and for activation of serum response element mediated transcription. RESULTS We identified several cassette substitutions that disrupt Gα12 binding to LARG and the related p115RhoGEF. These Gα12 mutants also were impaired in activating serum response element mediated signaling, a Rho-dependent response. Most of these mutants matched corresponding regions of Gα13 reported to contact p115RhoGEF, but unexpectedly, several RhoGEF-uncoupling mutations were found within the N- and C-terminal regions of Gα12. Trypsin protection assays revealed several mutants in these regions as retaining conformational activation. In addition, charge substitutions near the Gα12 N-terminus selectively disrupted binding to LARG but not p115RhoGEF. CONCLUSIONS Several structural aspects of the Gα12:RhoGEF interface differ from the reported Gα13:RhoGEF complex, particularly determinants within the C-terminal α5 helix and structurally uncharacterized N-terminus of Gα12. Furthermore, key residues at the Gα12 N-terminus may confer selectivity for LARG as a downstream effector.
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Affiliation(s)
- Benjamin J Ritchie
- Department of Biology, University of North Carolina at Asheville, One University Heights, Asheville, NC 28804, USA.
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Siehler S. G12/13-dependent signaling of G-protein-coupled receptors: disease context and impact on drug discovery. Expert Opin Drug Discov 2013; 2:1591-604. [PMID: 23488903 DOI: 10.1517/17460441.2.12.1591] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
G-protein-coupled receptors (GPCRs) transmit extracellular signals across the plasma membrane via intracellular activation of heterotrimeric G proteins. The signal transduction pathways of Gs, Gi and Gq protein families are widely studied, whereas signaling properties of G12 proteins are only emerging. Many GPCRs were found to couple to G12/13 proteins in addition to coupling to one or more other types of G proteins. G12/13 proteins couple GPCRs to activation of the small monomeric GTPase RhoA. Activation of RhoA modulates various downstream effector systems relevant to diseases such as hypertension, artherosclerosis, asthma and cancer. GPCR screening assays exist for Gs-, Gi- and Gq-linked pathways, whereas a drug-screening assay for the G12-Rho pathway was developed only recently. The review gives an overview of the present understanding of the G12/13-related biology of GPCRs.
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Affiliation(s)
- Sandra Siehler
- Novartis Institutes for BioMedical Research Basel, Center for Proteomic Chemistry, Novartis Pharma AG, WSJ-88.2.05, 4002 Basel, Switzerland +41 61 324 8946 ; +41 61 324 2870 ;
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Mikelis CM, Palmby TR, Simaan M, Li W, Szabo R, Lyons R, Martin D, Yagi H, Fukuhara S, Chikumi H, Galisteo R, Mukouyama YS, Bugge TH, Gutkind JS. PDZ-RhoGEF and LARG are essential for embryonic development and provide a link between thrombin and LPA receptors and Rho activation. J Biol Chem 2013; 288:12232-43. [PMID: 23467409 DOI: 10.1074/jbc.m112.428599] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
G protein-coupled receptors (GPCRs) linked to both members of the Gα12 family of heterotrimeric G proteins α subunits, Gα12 and Gα13, regulate the activation of Rho GTPases, thereby contributing to many key biological processes. Multiple Rho GEFs have been proposed to link Gα12/13 GPCRs to Rho activation, including PDZ-RhoGEF (PRG), leukemia-associated Rho GEF (LARG), p115-RhoGEF (p115), lymphoid blast crisis (Lbc), and Dbl. PRG, LARG, and p115 share the presence of a regulator of G protein signaling homology (RGS) domain. There is limited information on the biological roles of this RGS-containing family of RhoGEFs in vivo. p115-deficient mice are viable with some defects in the immune system and gastrointestinal motor dysfunctions, whereas in an initial study we showed that mice deficient for Larg are viable and resistant to salt-induced hypertension. Here, we generated knock-out mice for Prg and observed that these mice do not display any overt phenotype. However, deficiency in Prg and Larg leads to complex developmental defects and early embryonic lethality. Signaling from Gα11/q-linked GPCRs to Rho was not impaired in mouse embryonic fibroblasts defective in all three RGS-containing RhoGEFs. However, a combined lack of Prg, Larg, and p115 expression abolished signaling through Gα12/13 to Rho and thrombin-induced cell proliferation, directional migration, and nuclear signaling through JNK and p38. These findings provide evidence of an essential role for the RGS-containing RhoGEF family in signaling to Rho by Gα12/13-coupled GPCRs, which may likely play a critical role during embryonic development.
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Affiliation(s)
- Constantinos M Mikelis
- Oral and Pharyngeal Cancer Branch, NIDCR, Genetics and Developmental Biology Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA
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Ye D, Lin F. S1pr2/Gα13 signaling controls myocardial migration by regulating endoderm convergence. Development 2013; 140:789-99. [PMID: 23318642 DOI: 10.1242/dev.085340] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A key process during vertebrate heart development is the migration of bilateral populations of myocardial precursors towards the midline to form the primitive heart tube. In zebrafish, signaling mediated by sphingosine-1-phosphate (S1P) and its cognate G protein-coupled receptor (S1pr2/Mil) is essential for myocardial migration, but the underlying mechanisms remain undefined. Here, we show that suppression of Gα(13) signaling disrupts myocardial migration, leading to the formation of two bilaterally located hearts (cardia bifida). Genetic studies indicate that Gα(13) acts downstream of S1pr2 to regulate myocardial migration through a RhoGEF-dependent pathway. Furthermore, disrupting any component of the S1pr2/Gα(13)/RhoGEF pathway impairs endoderm convergence during segmentation, and the endodermal defects correlate with the extent of cardia bifida. Moreover, endoderm transplantation reveals that the presence of wild-type anterior endodermal cells in Gα(13)-deficient embryos is sufficient to rescue the endoderm convergence defect and cardia bifida, and, conversely, that the presence of anterior endodermal cells defective for S1pr2 or Gα(13) in wild-type embryos causes such defects. Thus, S1pr2/Gα(13) signaling probably acts in the endoderm to regulate myocardial migration. In support of this notion, cardiac-specific expression of Gα(13) fails to rescue cardia bifida in the context of global Gα(13) inhibition. Our data demonstrate for the first time that the Gα(13)/RhoGEF-dependent pathway functions downstream of S1pr2 to regulate convergent movement of the endoderm, an event that is crucial for coordinating myocardial migration.
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Affiliation(s)
- Ding Ye
- Department of Anatomy and Cell Biology, Carver College of Medicine, the University of Iowa, 1-400 Bowen Science Building, Iowa City, IA 52242-1109, USA
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Moolenaar WH, Houben AJS, Lee SJ, van Meeteren LA. Autotaxin in embryonic development. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:13-9. [PMID: 23022664 DOI: 10.1016/j.bbalip.2012.09.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/10/2012] [Accepted: 09/11/2012] [Indexed: 12/12/2022]
Abstract
Autotaxin (ATX) is a secreted lysophospholipase D that generates the multifunctional lipid mediator lysophosphatidic acid (LPA). LPA signals through six distinct G protein-coupled receptors, acting alone or in concert to activate multiple effector pathways. The ATX-LPA signaling axis is implicated in a remarkably wide variety of physiological and pathological processes and plays a vital role in embryonic development. Disruption of the ATX-encoding gene (Enpp2) in mice results in intrauterine death due to vascular defects in the extra-embryonic yolk sac and embryo proper. In addition, Enpp2 (-/-) embryos show impaired neural development. The observed angiogenic defects are attributable, at least in part, to loss of LPA signaling through the Gα(12/13)-linked RhoA-ROCK-actin remodeling pathway. Studies in zebrafish also have uncovered a dual role for ATX in both vascular and neural development; furthermore, they point to a key role for ATX-LPA signaling in the regulation of left-right asymmetry. Here we discuss our present understanding of the role of ATX-LPA signaling in vertebrate development. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.
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Affiliation(s)
- Wouter H Moolenaar
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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Takefuji M, Wirth A, Lukasova M, Takefuji S, Boettger T, Braun T, Althoff T, Offermanns S, Wettschureck N. G(13)-mediated signaling pathway is required for pressure overload-induced cardiac remodeling and heart failure. Circulation 2012; 126:1972-82. [PMID: 22972902 DOI: 10.1161/circulationaha.112.109256] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Cardiac remodeling in response to pressure or volume overload plays an important role in the pathogenesis of heart failure. Various mechanisms have been suggested to translate mechanical stress into structural changes, one of them being the release of humoral factors such as angiotensin II and endothelin-1, which in turn promote cardiac hypertrophy and fibrosis. A large body of evidence suggests that the prohypertrophic effects of these factors are mediated by receptors coupled to the G(q/11) family of heterotrimeric G proteins. Most G(q/11)-coupled receptors, however, can also activate G proteins of the G(12/13) family, but the role of G(12/13) in cardiac remodeling is not understood. METHODS AND RESULTS We use siRNA-mediated knockdown in vitro and conditional gene inactivation in vivo to study the role of the G(12/13) family in pressure overload-induced cardiac remodeling. We show in detail that inducible cardiomyocyte-specific inactivation of the α subunit of G(13), Gα(13), does not affect basal heart function but protects mice from pressure overload-induced hypertrophy and fibrosis as efficiently as inactivation of Gα(q/11). Furthermore, inactivation of Gα(13) prevents the development of heart failure up to 1 year after overloading. On the molecular level, we show that Gα(13), but not Gα(q/11), controls agonist-induced expression of hypertrophy-specific genes through activation of the small GTPase RhoA and consecutive activation of myocardin-related transcription factors. CONCLUSION Our data show that the G(12/13) family of heterotrimeric G proteins is centrally involved in pressure overload-induced cardiac remodeling and plays a central role in the transition to heart failure.
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Affiliation(s)
- Mikito Takefuji
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
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Current progress in non-Edg family LPA receptor research. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:33-41. [PMID: 22902318 DOI: 10.1016/j.bbalip.2012.08.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 08/01/2012] [Accepted: 08/02/2012] [Indexed: 01/08/2023]
Abstract
Lysophosphatidic acid (LPA) is the simplest phospholipid yet possesses myriad biological functions. Until 2003, the functions of LPA were thought to be elicited exclusively by three subtypes of the endothelial differentiation gene (Edg) family of G protein-coupled receptors - LPA(1), LPA(2), and LPA(3). However, several biological functions of LPA could not be assigned to any of these receptors indicating the existence of one or more additional LPA receptor(s). More recently, the discovery of a second cluster of LPA receptors which includes LPA(4), LPA(5), and LPA(6) has paved the way for new avenues of LPA research. Analyses of these non-Edg family LPA receptors have begun to fill in gaps to understand biological functions of LPA such as platelet aggregation and vascular development that could not be ascribed to classical Edg family LPA receptors and are also unveiling new biological functions. Here we review recent progress in the non-Edg family LPA receptor research, with special emphasis on the pharmacology, signaling, and physiological roles of this family of receptors. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.
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Gan X, Wang J, Wang C, Sommer E, Kozasa T, Srinivasula S, Alessi D, Offermanns S, Simon MI, Wu D. PRR5L degradation promotes mTORC2-mediated PKC-δ phosphorylation and cell migration downstream of Gα12. Nat Cell Biol 2012; 14:686-96. [PMID: 22609986 PMCID: PMC3389271 DOI: 10.1038/ncb2507] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 04/18/2012] [Indexed: 12/17/2022]
Abstract
Mammalian target of rapamycin complex (MTORC) 2 phosphorylates AGC protein kinases including PKC and regulates cellular functions including cell migration. However, its regulation remains poorly understood. Here we show that LPA induces two phases of PKCδ hydrophobic motif (HM) phosphorylation. The late phase is mediated by Gα12, which specifically activates ARAF, leading to upregulation of the expression of an E3 ubiquitin ligase RFFL and subsequent ubiquitination and degradation of PRR5L. Destabilization of PRR5L, a suppressor of mTORC2-mediated HM phosphorylation of PKCδ, but not AKT, results in PKCδ HM phosphorylation and activation. This Gα12-mediated pathway is critically important for fibroblast migration and pulmonary fibrosis development. Thus, our study unravels a signaling pathway for mTORC2 regulation and fibroblast migration.
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Affiliation(s)
- Xiaoqing Gan
- Department of Pharmacology and Program in Vascular Biology and Therapeutics, Yale School of Medicine, New Haven, Connecticut 06520, USA
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