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Elgazzaz M, Lakkappa N, Berdasco C, Mohan UP, Nuzzo A, Restivo L, Martinez A, Scarborough A, Guidry JJ, Sriramula S, Xu J, Daoud H, Mendiola Plá MA, Bowles DE, Beyer AM, Mauvais-Jarvis F, Yue X, Filipeanu CM, Lazartigues E. UBR1 Promotes Sex-Dependent ACE2 Ubiquitination in Hypertension. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.23.24307722. [PMID: 38826318 PMCID: PMC11142264 DOI: 10.1101/2024.05.23.24307722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Background Angiotensin (Ang)-II impairs the function of the antihypertensive enzyme ACE2 by promoting its internalization, ubiquitination and degradation thus contributing to hypertension. However, few ACE2 ubiquitination partners have been identified and their role in hypertension remains unknown. Methods Proteomics and bioinformatic analysis were used to identify ACE2 ubiquitination partners in the brain, heart, and kidney from Ang-II-infused C57BL6/J mice from both sexes and validated the interaction between UBR1 and ACE2 in cells. Central and peripheral UBR1 knockdown was then performed in male mice to investigate its role in the maintenance of hypertension. Results Proteomics analysis from hypothalamus identified UBR1 as a potential E3 ligase promoting ACE2 ubiquitination. Enhanced UBR1 expression, associated with ACE2 reduction, was confirmed in various tissues from hypertensive male mice and human samples. Treatment of endothelial and smooth muscle cells with testosterone, but not 17β-estradiol, confirmed a sex-specific regulation of UBR1. In vivo silencing of UBR1 using chronic administration of small interference RNA resulted in the restoration of ACE2 levels in hypertensive males. A transient decrease in blood pressure following intracerebroventricular, but not systemic, infusion was also observed. Interestingly, UBR1 knockdown increased the brain activation of Nedd4-2, an E3 ligase promoting ACE2 ubiquitination and reduced expression of SGK1, the kinase inactivating Nedd4-2. Conclusions: These data demonstrate that UBR1 is a novel ubiquitin ligase targeting ACE2 in hypertension. UBR1 and Nedd4-2 E3 ligases appear to work synergistically to ubiquitinate ACE2. Targeting of these ubiquitin ligases may represent a novel strategy to restore ACE2 compensatory activity in hypertension.
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Spies LML, Verhoog NJD, Louw A. Acquired Glucocorticoid Resistance Due to Homologous Glucocorticoid Receptor Downregulation: A Modern Look at an Age-Old Problem. Cells 2021; 10:2529. [PMID: 34685511 PMCID: PMC8533966 DOI: 10.3390/cells10102529] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/15/2021] [Accepted: 09/21/2021] [Indexed: 12/11/2022] Open
Abstract
For over 70 years, the unique anti-inflammatory properties of glucocorticoids (GCs), which mediate their effects via the ligand-activated transcription factor, the glucocorticoid receptor alpha (GRα), have allowed for the use of these steroid hormones in the treatment of various autoimmune and inflammatory-linked diseases. However, aside from the onset of severe side-effects, chronic GC therapy often leads to the ligand-mediated downregulation of the GRα which, in turn, leads to a decrease in GC sensitivity, and effectively, the development of acquired GC resistance. Although the ligand-mediated downregulation of GRα is well documented, the precise factors which influence this process are not well understood and, thus, the development of an acquired GC resistance presents an ever-increasing challenge to the pharmaceutical industry. Recently, however, studies have correlated the dimerization status of the GRα with its ligand-mediated downregulation. Therefore, the current review will be discussing the major role-players in the homologous downregulation of the GRα pool, with a specific focus on previously reported GC-mediated reductions in GRα mRNA and protein levels, the molecular mechanisms through which the GRα functional pool is maintained and the possible impact of receptor conformation on GC-mediated GRα downregulation.
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Affiliation(s)
| | | | - Ann Louw
- Department of Biochemistry, Stellenbosch University, Van de Byl Street, Stellenbosch 7200, South Africa; (L.-M.L.S.); (N.J.D.V.)
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Leboeuf D, Abakumova T, Prikazchikova T, Rhym L, Anderson DG, Zatsepin TS, Piatkov KI. Downregulation of the Arg/N-degron Pathway Sensitizes Cancer Cells to Chemotherapy In Vivo. Mol Ther 2020; 28:1092-1104. [PMID: 32087767 DOI: 10.1016/j.ymthe.2020.01.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/16/2020] [Indexed: 02/07/2023] Open
Abstract
The N-degron pathway is an emerging target for anti-tumor therapies, because of its capacity to positively regulate many hallmarks of cancer, including angiogenesis, cell proliferation, motility, and survival. Thus, inhibition of the N-degron pathway offers the potential to be a highly effective anti-cancer treatment. With the use of a small interfering RNA (siRNA)-mediated approach for selective downregulation of the four Arg/N-degron-dependent ubiquitin ligases, UBR1, UBR2, UBR4, and UBR5, we demonstrated decreased cell migration and proliferation and increased spontaneous apoptosis in cancer cells. Chronic treatment with lipid nanoparticles (LNPs) loaded with siRNA in mice efficiently downregulates the expression of UBR-ubiquitin ligases in the liver without any significant toxic effects but engages the immune system and causes inflammation. However, when used in a lower dose, in combination with a chemotherapeutic drug, downregulation of the Arg/N-degron pathway E3 ligases successfully reduced tumor load by decreasing proliferation and increasing apoptosis in a mouse model of hepatocellular carcinoma, while avoiding the inflammatory response. Our study demonstrates that UBR-ubiquitin ligases of the Arg/N-degron pathway are promising targets for the development of improved therapies for many cancer types.
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Affiliation(s)
| | | | | | - Luke Rhym
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Daniel G Anderson
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard and MIT Division of Health Science and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
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Louw A. GR Dimerization and the Impact of GR Dimerization on GR Protein Stability and Half-Life. Front Immunol 2019; 10:1693. [PMID: 31379877 PMCID: PMC6653659 DOI: 10.3389/fimmu.2019.01693] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022] Open
Abstract
Pharmacologically, glucocorticoids, which mediate their effects via the glucocorticoid receptor (GR), are a most effective therapy for inflammatory diseases despite the fact that chronic use causes side-effects and acquired GC resistance. The design of drugs with fewer side-effects and less potential for the development of resistance is therefore considered crucial for improved therapy. Dimerization of the GR is an integral step in glucocorticoid signaling and has been identified as a possible molecular site to target for drug development of anti-inflammatory drugs with an improved therapeutic index. Most of the current understanding regarding the role of GR dimerization in GC signaling derives for dimerization deficient mutants, although the role of ligands biased toward monomerization has also been described. Even though designing for loss of dimerization has mostly been applied for reduction of side-effect profile, designing for loss of dimerization may also be a fruitful strategy for the development of GC drugs with less potential to develop GC resistance. GC-induced resistance affects up to 30% of users and is due to a reduction in the GR functional pool. Several molecular mechanisms of GC-mediated reductions in GR pool have been described, one of which is the autologous down-regulation of GR density by the ubiquitin-proteasome-system (UPS). Loss of GR dimerization prevents autologous down-regulation of the receptor through modulation of interactions with components of the UPS and post-translational modifications (PTMs), such as phosphorylation, which prime the GR for degradation. Rational design of conformationally biased ligands that select for a monomeric GR conformation, which increases GC sensitivity through improving GR protein stability and increasing half-life, may be a productive avenue to explore. However, potential drawbacks to this approach should be considered as well as the advantages and disadvantages in chronic vs. acute treatment regimes.
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Affiliation(s)
- Ann Louw
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
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Wilkinson L, Verhoog NJD, Louw A. Disease- and treatment-associated acquired glucocorticoid resistance. Endocr Connect 2018; 7:R328-R349. [PMID: 30352419 PMCID: PMC6280593 DOI: 10.1530/ec-18-0421] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 10/11/2018] [Indexed: 12/16/2022]
Abstract
The development of resistance to glucocorticoids (GCs) in therapeutic regimens poses a major threat. Generally, GC resistance is congenital or acquired over time as a result of disease progression, prolonged GC treatment or, in some cases, both. Essentially, disruptions in the function and/or pool of the glucocorticoid receptor α (GRα) underlie this resistance. Many studies have detailed how alterations in GRα function lead to diminished GC sensitivity; however, the current review highlights the wealth of data concerning reductions in the GRα pool, mediated by disease-associated and treatment-associated effects, which contribute to a significant decrease in GC sensitivity. Additionally, the current understanding of the molecular mechanisms involved in driving reductions in the GRα pool is discussed. After highlighting the importance of maintaining the level of the GRα pool to combat GC resistance, we present current strategies and argue that future strategies to prevent GC resistance should involve biased ligands with a predisposition for reduced GR dimerization, a strategy originally proposed as the SEMOGRAM-SEDIGRAM concept to reduce the side-effect profile of GCs.
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Affiliation(s)
- Legh Wilkinson
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | | | - Ann Louw
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
- Correspondence should be addressed to A Louw:
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Hantouche C, Williamson B, Valinsky WC, Solomon J, Shrier A, Young JC. Bag1 Co-chaperone Promotes TRC8 E3 Ligase-dependent Degradation of Misfolded Human Ether a Go-Go-related Gene (hERG) Potassium Channels. J Biol Chem 2016; 292:2287-2300. [PMID: 27998983 DOI: 10.1074/jbc.m116.752618] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 12/02/2016] [Indexed: 11/06/2022] Open
Abstract
Cardiac long QT syndrome type 2 is caused by mutations in the human ether a go-go-related gene (hERG) potassium channel, many of which cause misfolding and degradation at the endoplasmic reticulum instead of normal trafficking to the cell surface. The Hsc70/Hsp70 chaperones assist the folding of the hERG cytosolic domains. Here, we demonstrate that the Hsp70 nucleotide exchange factor Bag1 promotes hERG degradation by the ubiquitin-proteasome system at the endoplasmic reticulum to regulate hERG levels and channel activity. Dissociation of hERG complexes containing Hsp70 and the E3 ubiquitin ligase CHIP requires the interaction of Bag1 with Hsp70, but this does not involve the Bag1 ubiquitin-like domain. The interaction with Bag1 then shifts hERG degradation to the membrane-anchored E3 ligase TRC8 and its E2-conjugating enzyme Ube2g2, as determined by siRNA screening. TRC8 interacts through the transmembrane region with hERG and decreases hERG functional expression. TRC8 also mediates degradation of the misfolded hERG-G601S disease mutant, but pharmacological stabilization of the mutant structure prevents degradation. Our results identify TRC8 as a previously unknown Hsp70-independent quality control E3 ligase for hERG.
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Affiliation(s)
- Christine Hantouche
- From the Departments of Physiology and.,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Brittany Williamson
- Biochemistry and.,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - William C Valinsky
- From the Departments of Physiology and.,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Joshua Solomon
- From the Departments of Physiology and.,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Alvin Shrier
- From the Departments of Physiology and .,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Jason C Young
- Biochemistry and .,Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada
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Okabe T, Chavan R, Fonseca Costa SS, Brenna A, Ripperger JA, Albrecht U. REV-ERBα influences the stability and nuclear localization of the glucocorticoid receptor. J Cell Sci 2016; 129:4143-4154. [PMID: 27686098 PMCID: PMC5117207 DOI: 10.1242/jcs.190959] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 09/17/2016] [Indexed: 12/22/2022] Open
Abstract
REV-ERBα (encoded by Nr1d1) is a nuclear receptor that is part of the circadian clock mechanism and regulates metabolism and inflammatory processes. The glucocorticoid receptor (GR, encoded by Nr3c1) influences similar processes, but is not part of the circadian clock, although glucocorticoid signaling affects resetting of the circadian clock in peripheral tissues. Because of their similar impact on physiological processes, we studied the interplay between these two nuclear receptors. We found that REV-ERBα binds to the C-terminal portion and GR to the N-terminal portion of HSP90α and HSP90β, a chaperone responsible for the activation of proteins to ensure survival of a cell. The presence of REV-ERBα influences the stability and nuclear localization of GR by an unknown mechanism, thereby affecting expression of GR target genes, such as IκBα (Nfkbia) and alcohol dehydrogenase 1 (Adh1). Our findings highlight an important interplay between two nuclear receptors that influence the transcriptional potential of each other. This indicates that the transcriptional landscape is strongly dependent on dynamic processes at the protein level.
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Affiliation(s)
- Takashi Okabe
- Dept. of Biology, Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Rohit Chavan
- Dept. of Biology, Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Sara S Fonseca Costa
- Dept. of Biology, Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Andrea Brenna
- Dept. of Biology, Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Jürgen A Ripperger
- Dept. of Biology, Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
| | - Urs Albrecht
- Dept. of Biology, Biochemistry, University of Fribourg, Fribourg 1700, Switzerland
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Helzer KT, Hooper C, Miyamoto S, Alarid ET. Ubiquitylation of nuclear receptors: new linkages and therapeutic implications. J Mol Endocrinol 2015; 54:R151-67. [PMID: 25943391 PMCID: PMC4457637 DOI: 10.1530/jme-14-0308] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/05/2015] [Indexed: 12/25/2022]
Abstract
The nuclear receptor (NR) superfamily is a group of transcriptional regulators that control multiple aspects of both physiology and pathology and are broadly recognized as viable therapeutic targets. While receptor-modulating drugs have been successful in many cases, the discovery of new drug targets is still an active area of research, because resistance to NR-targeting therapies remains a significant clinical challenge. Many successful targeted therapies have harnessed the control of receptor activity by targeting events within the NR signaling pathway. In this review, we explore the role of NR ubiquitylation and discuss how the expanding roles of ubiquitin could be leveraged to identify additional entry points to control receptor function for future therapeutic development.
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Affiliation(s)
- Kyle T Helzer
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, 6151 Wisconsin Institutes for Medical Research, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Christopher Hooper
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, 6151 Wisconsin Institutes for Medical Research, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Shigeki Miyamoto
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, 6151 Wisconsin Institutes for Medical Research, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Elaine T Alarid
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, 6151 Wisconsin Institutes for Medical Research, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
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Gibbs DJ, Bacardit J, Bachmair A, Holdsworth MJ. The eukaryotic N-end rule pathway: conserved mechanisms and diverse functions. Trends Cell Biol 2014; 24:603-11. [DOI: 10.1016/j.tcb.2014.05.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 04/30/2014] [Accepted: 05/01/2014] [Indexed: 12/30/2022]
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