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Barber CV, Yo JH, Rahman RA, Wallace EM, Palmer KR, Marshall SA. Activin A and pathologies of pregnancy: a review. Placenta 2023; 136:35-41. [PMID: 37028223 DOI: 10.1016/j.placenta.2023.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/13/2023] [Accepted: 03/30/2023] [Indexed: 04/05/2023]
Abstract
Activin A is a two-subunit protein belonging to the transforming growth factor β superfamily. First discovered almost three decades ago, it has since been implicated in diverse physiological roles, ranging from wound repair to reproduction. After 30 years of research, altered activin A levels are now understood to be associated with the development of various diseases, making activin A a potential therapeutic target. In pregnancy, the placenta and fetal membranes are major producers of activin A, with significantly enhanced serum concentrations now recognised as a contributor to numerous gestational disorders. Evidence now suggests that circulating levels of activin A may be clinically relevant in the early detection of pregnancy complications, including miscarriage and preeclampsia. This review aims to summarise our current understanding of activin A as a potential diagnostic marker in common pregnancy pathologies.
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Kappes EC, Kattamuri C, Czepnik M, Yarawsky AE, Brûlé E, Wang Y, Ongaro L, Herr AB, Walton KL, Bernard DJ, Thompson TB. Follistatin Forms a Stable Complex With Inhibin A That Does Not Interfere With Activin A Antagonism. Endocrinology 2023; 164:7010688. [PMID: 36718082 DOI: 10.1210/endocr/bqad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 02/01/2023]
Abstract
Inhibins are transforming growth factor-β family heterodimers that suppress follicle-stimulating hormone (FSH) secretion by antagonizing activin class ligands. Inhibins share a common β chain with activin ligands. Follistatin is another activin antagonist, known to bind the common β chain of both activins and inhibins. In this study, we characterized the antagonist-antagonist complex of inhibin A and follistatin to determine if their interaction impacted activin A antagonism. We isolated the inhibin A:follistatin 288 complex, showing that it forms in a 1:1 stoichiometric ratio, different from previously reported homodimeric ligand:follistatin complexes, which bind in a 1:2 ratio. Small angle X-ray scattering coupled with modeling provided a low-resolution structure of inhibin A in complex with follistatin 288. Inhibin binds follistatin via the shared activin β chain, leaving the α chain free and flexible. The inhibin A:follistatin 288 complex was also shown to bind heparin with lower affinity than follistatin 288 alone or in complex with activin A. Characterizing the inhibin A:follistatin 288 complex in an activin-responsive luciferase assay and by surface plasmon resonance indicated that the inhibitor complex readily dissociated upon binding type II receptor activin receptor type IIb, allowing both antagonists to inhibit activin signaling. Additionally, injection of the complex in ovariectomized female mice did not alter inhibin A suppression of FSH. Taken together, this study shows that while follistatin binds to inhibin A with a substochiometric ratio relative to the activin homodimer, the complex can dissociate readily, allowing both proteins to effectively antagonize activin signaling.
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Affiliation(s)
- Emily C Kappes
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH, USA
| | - Chandramohan Kattamuri
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH, USA
| | - Magdalena Czepnik
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH, USA
| | | | - Emilie Brûlé
- Departments of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Ying Wang
- Departments of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Luisina Ongaro
- Departments of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Andrew B Herr
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Kelly L Walton
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
- Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Daniel J Bernard
- Departments of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Departments of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Thomas B Thompson
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, OH, USA
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3
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Lodberg A. Principles of the activin receptor signaling pathway and its inhibition. Cytokine Growth Factor Rev 2021; 60:1-17. [PMID: 33933900 DOI: 10.1016/j.cytogfr.2021.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 01/19/2023]
Abstract
This review captures the anabolic and stimulatory effects observed with inhibition of the transforming growth factor β superfamily in muscle, blood, and bone. New medicinal substances that rectify activin, myostatin, and growth differentiation factor 11 signaling give hope to the many whose lives are affected by deterioration of these tissues. The review first covers the origin, structure, and common pathway of activins, myostatin, and growth differentiation factor 11 along with the pharmacodynamics of the new class of molecules designed to oppose the activin receptor signaling pathway. Current terminology surrounding this new class of molecules is inconsistent and does not infer functionality. Adopting inhibitors of the activin receptor signaling pathway (IASPs) as a generic term is proposed because it encapsulates the molecular mechanisms along the pathway trajectory. To conclude, a pragmatic classification of IASPs is presented that integrates functionality and side effects based on the data available from animals and humans. This provides researchers and clinicians with a tool to tailor IASPs therapy according to the need of projects or patients and with respect to side effects.
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Affiliation(s)
- Andreas Lodberg
- Department of Biomedicine, Aarhus University, Department of Respiratory Diseases and Allergy, Aarhus University Hospital, Wilhelm Meyers Allé, DK-8000, Aarhus, Denmark.
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Zhong X, Pons M, Poirier C, Jiang Y, Liu J, Sandusky GE, Shahda S, Nakeeb A, Schmidt CM, House MG, Ceppa EP, Zyromski NJ, Liu Y, Jiang G, Couch ME, Koniaris LG, Zimmers TA. The systemic activin response to pancreatic cancer: implications for effective cancer cachexia therapy. J Cachexia Sarcopenia Muscle 2019; 10:1083-1101. [PMID: 31286691 PMCID: PMC6818463 DOI: 10.1002/jcsm.12461] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 04/19/2019] [Accepted: 05/14/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is a particularly lethal malignancy partly due to frequent, severe cachexia. Serum activin correlates with cachexia and mortality, while exogenous activin causes cachexia in mice. METHODS Isoform-specific activin expression and activities were queried in human and murine tumours and PDAC models. Activin inhibition was by administration of soluble activin type IIB receptor (ACVR2B/Fc) and by use of skeletal muscle specific dominant negative ACVR2B expressing transgenic mice. Feed-forward activin expression and muscle wasting activity were tested in vivo and in vitro on myotubes. RESULTS Murine PDAC tumour-derived cell lines expressed activin-βA but not activin-βB. Cachexia severity increased with activin expression. Orthotopic PDAC tumours expressed activins, induced activin expression by distant organs, and produced elevated serum activins. Soluble factors from PDAC elicited activin because conditioned medium from PDAC cells induced activin expression, activation of p38 MAP kinase, and atrophy of myotubes. The activin trap ACVR2B/Fc reduced tumour growth, prevented weight loss and muscle wasting, and prolonged survival in mice with orthotopic tumours made from activin-low cell lines. ACVR2B/Fc also reduced cachexia in mice with activin-high tumours. Activin inhibition did not affect activin expression in organs. Hypermuscular mice expressing dominant negative ACVR2B in muscle were protected for weight loss but not mortality when implanted with orthotopic tumours. Human tumours displayed staining for activin, and expression of the gene encoding activin-βA (INHBA) correlated with mortality in patients with PDAC, while INHBB and other related factors did not. CONCLUSIONS Pancreatic adenocarcinoma tumours are a source of activin and elicit a systemic activin response in hosts. Human tumours express activins and related factors, while mortality correlates with tumour activin A expression. PDAC tumours also choreograph a systemic activin response that induces organ-specific and gene-specific expression of activin isoforms and muscle wasting. Systemic blockade of activin signalling could preserve muscle and prolong survival, while skeletal muscle-specific activin blockade was only protective for weight loss. Our findings suggest the potential and need for gene-specific and organ-specific interventions. Finally, development of more effective cancer cachexia therapy might require identifying agents that effectively and/or selectively inhibit autocrine vs. paracrine activin signalling.
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Affiliation(s)
- Xiaoling Zhong
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IUPUI Center for Cachexia Innovation, Research and TherapyIndianapolisINUSA
| | - Marianne Pons
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
| | - Christophe Poirier
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
| | - Yanlin Jiang
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
| | - Jianguo Liu
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
| | - George E. Sandusky
- Department of Pathology and Laboratory MedicineIndiana University School of MedicineIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
| | - Safi Shahda
- IU Simon Cancer CenterIndianapolisINUSA
- Department of MedicineIndiana University School of MedicineIndianapolisINUSA
| | - Attila Nakeeb
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
| | - C. Max Schmidt
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
| | - Michael G. House
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
| | - Eugene P. Ceppa
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
| | - Nicholas J. Zyromski
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
| | - Yunlong Liu
- IUPUI Center for Cachexia Innovation, Research and TherapyIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
- Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisINUSA
| | - Guanglong Jiang
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
| | - Marion E. Couch
- IU Simon Cancer CenterIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisINUSA
- Department of Otolaryngology—Head & Neck SurgeryIndiana University School of MedicineIndianapolisINUSA
| | - Leonidas G. Koniaris
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IUPUI Center for Cachexia Innovation, Research and TherapyIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisINUSA
| | - Teresa A. Zimmers
- Department of SurgeryIndiana University School of MedicineIndianapolisINUSA
- IUPUI Center for Cachexia Innovation, Research and TherapyIndianapolisINUSA
- IU Simon Cancer CenterIndianapolisINUSA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisINUSA
- Department of Otolaryngology—Head & Neck SurgeryIndiana University School of MedicineIndianapolisINUSA
- Department of Anatomy, Cell Biology & PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Department of Biochemistry and Molecular BiologyIndiana University School of MedicineIndianapolisINUSA
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Walton KL, Chen JL, Arnold Q, Kelly E, La M, Lu L, Lovrecz G, Hagg A, Colgan TD, Qian H, Gregorevic P, Harrison CA. Activin A-Induced Cachectic Wasting Is Attenuated by Systemic Delivery of Its Cognate Propeptide in Male Mice. Endocrinology 2019; 160:2417-2426. [PMID: 31322699 DOI: 10.1210/en.2019-00257] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/12/2019] [Indexed: 12/12/2022]
Abstract
In cancer, elevated activin levels promote cachectic wasting of muscle, irrespective of tumor progression. In excess, activins A and B use the myostatin signaling pathway in muscle, triggering a decrease in protein synthesis and an increase in protein degradation, which ultimately leads to atrophy. Recently, we demonstrated that local delivery of engineered activin and myostatin propeptides (natural inhibitors of these growth factors) could induce profound muscle hypertrophy in healthy mice. Additionally, the expression of these propeptides effectively attenuated localized muscle wasting in models of dystrophy and cancer cachexia. In this study, we examined whether a systemically administered recombinant propeptide could reverse activin A-induced cachectic wasting in mice. Chinese hamster ovary cells stably expressing activin A were transplanted into the quadriceps of nude mice and caused an 85-fold increase in circulating activin A levels within 12 days. Elevated activin A induced a rapid reduction in body mass (-16%) and lean mass (-10%). In agreement with previous findings, we demonstrated that adeno-associated virus-mediated delivery of activin propeptide to the tibialis anterior muscle blocked activin-induced wasting. In addition, despite massively elevated levels of activin A in this model, systemic delivery of the propeptide significantly reduced activin-induced changes in lean and body mass. Specifically, recombinant propeptide reversed activin-induced wasting of skeletal muscle, heart, liver, and kidneys. This is the first study to demonstrate that systemic administration of recombinant propeptide therapy effectively attenuates tumor-derived activin A insult in multiple tissues.
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Affiliation(s)
- Kelly L Walton
- Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Justin L Chen
- Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Quinn Arnold
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | - Emily Kelly
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Mylinh La
- National Collaborative Research Infrastructure Strategy Facility, Commonwealth Scientific and Industrial Research Organisation BioMedical Manufacturing Program, Clayton, Victoria, Australia
| | - Louis Lu
- National Collaborative Research Infrastructure Strategy Facility, Commonwealth Scientific and Industrial Research Organisation BioMedical Manufacturing Program, Clayton, Victoria, Australia
| | - George Lovrecz
- National Collaborative Research Infrastructure Strategy Facility, Commonwealth Scientific and Industrial Research Organisation BioMedical Manufacturing Program, Clayton, Victoria, Australia
| | - Adam Hagg
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Department of Physiology, Centre for Muscle Research, The University of Melbourne, Melbourne, Victoria, Australia
| | - Timothy D Colgan
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Hongwei Qian
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Department of Physiology, Centre for Muscle Research, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul Gregorevic
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
- Department of Physiology, Centre for Muscle Research, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington
| | - Craig A Harrison
- Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
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Garito T, Zakaria M, Papanicolaou DA, Li Y, Pinot P, Petricoul O, Laurent D, Rooks D, Rondon JC, Roubenoff R. Effects of bimagrumab, an activin receptor type II inhibitor, on pituitary neurohormonal axes. Clin Endocrinol (Oxf) 2018; 88:908-919. [PMID: 29566437 DOI: 10.1111/cen.13601] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Bimagrumab is a human monoclonal antibody inhibitor of activin type II receptors (ActRII), with anabolic action on skeletal muscle mass by blocking binding of myostatin and other negative regulators of muscle growth. Bimagrumab is under evaluation for muscle wasting and associated functional loss in hip fracture and sarcopenia, and in obesity. Bimagrumab also blocks other endogenous ActRII ligands, such as activins, which act on the neurohormonal axes, pituitary, gonads and adrenal glands. AIM To evaluate the effect of bimagrumab on the pituitary-gonadal and pituitary-adrenal axes in humans. METHODS Healthy men and women, aged 55 to 75 years, received bimagrumab intravenously 10 mg/kg or placebo on Day 1 and Day 29. Pituitary-gonadal and pituitary-adrenal functions were evaluated with basal hormone measurement and standard gonadotropin-releasing hormone (GnRH) and adrenocorticotropic hormone (ACTH) stimulation tests at baseline, Week 8 and at the end of study (EOS)-Week 20. RESULTS At Week 8, follicle-stimulating hormone (FSH) levels were reduced by 42.16 IU/L (P < .001) and luteinizing hormone (LH) levels were increased by 2.5 IU/L (P = .08) over placebo in response to bimagrumab in women but not in men. Effects that were reversible after bimagrumab was cleared. Gonadal and adrenal androgen levels were not affected by exposure to bimagrumab. CONCLUSION Bimagrumab alters the function of pituitary gonadotroph cells, consistent with blockade of activin on local ActRII. This effect is reversible with clearance of bimagrumab. Bimagrumab did not impact gonadal and adrenal androgen secretion.
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Affiliation(s)
- Tania Garito
- San Raffaele Diabetes Research Institute, Milan, Italy
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | - Yifang Li
- Novartis Institutes for BioMedical Research, Cambridge, USA
| | - Pascale Pinot
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Didier Laurent
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Daniel Rooks
- Novartis Institutes for BioMedical Research, Cambridge, USA
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Anderson EN, Wharton KA. Alternative cleavage of the bone morphogenetic protein (BMP), Gbb, produces ligands with distinct developmental functions and receptor preferences. J Biol Chem 2017; 292:19160-19178. [PMID: 28924042 DOI: 10.1074/jbc.m117.793513] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/14/2017] [Indexed: 12/27/2022] Open
Abstract
The family of TGF-β and bone morphogenetic protein (BMP) signaling proteins has numerous developmental and physiological roles. They are made as proprotein dimers and then cleaved by proprotein convertases to release the C-terminal domain as an active ligand dimer. Multiple proteolytic processing sites in Glass bottom boat (Gbb), the Drosophila BMP7 ortholog, can produce distinct ligand forms. Cleavage at the S1 or atypical S0 site in Gbb produces Gbb15, the conventional small BMP ligand, whereas NS site cleavage produces a larger Gbb38 ligand. We hypothesized that the Gbb prodomain is involved not only in regulating the production of specific ligands but also their signaling output. We found that blocking NS cleavage increased association of the full-length prodomain with Gbb15, resulting in a concomitant decrease in signaling activity. Moreover, NS cleavage was required in vivo for Gbb-Decapentaplegic (Dpp) heterodimer-mediated wing vein patterning but not for Gbb15-Dpp heterodimer activity in cell culture. Gbb NS cleavage was also required for viability through its regulation of pupal ecdysis in a type II receptor Wishful thinking (Wit)-dependent manner. In fact, Gbb38-mediated signaling exhibits a preference for Wit over the other type II receptor Punt. Finally, we discovered that Gbb38 is produced when processing at the S1/S0 site is blocked by O-linked glycosylation in third instar larvae. Our findings demonstrate that BMP prodomain cleavage ensures that the mature ligand is not inhibited by the prodomain. Furthermore, alternative processing of BMP proproteins produces ligands that signal through different receptors and exhibit specific developmental functions.
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Affiliation(s)
- Edward N Anderson
- From the Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912
| | - Kristi A Wharton
- From the Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912
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8
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Puolakkainen T, Ma H, Kainulainen H, Pasternack A, Rantalainen T, Ritvos O, Heikinheimo K, Hulmi JJ, Kiviranta R. Treatment with soluble activin type IIB-receptor improves bone mass and strength in a mouse model of Duchenne muscular dystrophy. BMC Musculoskelet Disord 2017; 18:20. [PMID: 28103859 PMCID: PMC5244551 DOI: 10.1186/s12891-016-1366-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/14/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Inhibition of activin/myostatin pathway has emerged as a novel approach to increase muscle mass and bone strength. Duchenne muscular dystrophy (DMD) is a neuromuscular disorder that leads to progressive muscle degeneration and also high incidence of fractures. The aim of our study was to test whether inhibition of activin receptor IIB ligands with or without exercise could improve bone strength in the mdx mouse model for DMD. METHODS Thirty-two mdx mice were divided to running and non-running groups and to receive either PBS control or soluble activin type IIB-receptor (ActRIIB-Fc) once weekly for 7 weeks. RESULTS Treatment of mdx mice with ActRIIB-Fc resulted in significantly increased body and muscle weights in both sedentary and exercising mice. Femoral μCT analysis showed increased bone volume and trabecular number (BV/TV +80%, Tb.N +70%, P < 0.05) in both ActRIIB-Fc treated groups. Running also resulted in increased bone volume and trabecular number in PBS-treated mice. However, there was no significant difference in trabecular bone structure or volumetric bone mineral density between the ActRIIB-Fc and ActRIIB-Fc-R indicating that running did not further improve bone structure in ActRIIB-Fc-treated mice. ActRIIB-Fc increased bone mass also in vertebrae (BV/TV +20%, Tb.N +30%, P < 0.05) but the effects were more modest. The number of osteoclasts was decreased in histological analysis and the expression of several osteoblast marker genes was increased in ActRIIB-Fc treated mice suggesting decreased bone resorption and increased bone formation in these mice. Increased bone mass in femurs translated into enhanced bone strength in biomechanical testing as the maximum force and stiffness were significantly elevated in ActRIIB-Fc-treated mice. CONCLUSIONS Our results indicate that treatment of mdx mice with the soluble ActRIIB-Fc results in a robust increase in bone mass, without any additive effect by voluntary running. Thus ActRIIB-Fc could be an attractive option in the treatment of musculoskeletal disorders.
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Affiliation(s)
- Tero Puolakkainen
- Department of Medical Biochemistry and Genetics, University of Turku, Kiinamyllynkatu 10, FI-20520, Turku, Finland
| | - Hongqian Ma
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland.,Institute of Dentistry, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Heikki Kainulainen
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland
| | - Arja Pasternack
- Department of Physiology, University of Helsinki, Helsinki, Finland
| | - Timo Rantalainen
- Centre for Physical Activity and Nutrition Research, Deakin University, Melbourne, Australia
| | - Olli Ritvos
- Department of Physiology, University of Helsinki, Helsinki, Finland
| | - Kristiina Heikinheimo
- Department of Oral and Maxillofacial Surgery, Institute of Dentistry, University of Turku, Turku, Finland.,Department of Oral Diagnostic Sciences, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland.,Kuopio University Hospital, Kuopio, Finland
| | - Juha J Hulmi
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland.,Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Riku Kiviranta
- Department of Medical Biochemistry and Genetics, University of Turku, Kiinamyllynkatu 10, FI-20520, Turku, Finland. .,Department of Endocrinology, Turku University Hospital, Turku, Finland.
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9
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Wang X, Fischer G, Hyvönen M. Structure and activation of pro-activin A. Nat Commun 2016; 7:12052. [PMID: 27373274 PMCID: PMC4932183 DOI: 10.1038/ncomms12052] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/24/2016] [Indexed: 12/19/2022] Open
Abstract
Activins are growth factors with multiple roles in the development and homeostasis. Like all TGF-β family of growth factors, activins are synthesized as large precursors from which mature dimeric growth factors are released proteolytically. Here we have studied the activation of activin A and determined crystal structures of the unprocessed precursor and of the cleaved pro-mature complex. Replacing the natural furin cleavage site with a HRV 3C protease site, we show how the protein gains its bioactivity after proteolysis and is as active as the isolated mature domain. The complex remains associated in conditions used for biochemical analysis with a dissociation constant of 5 nM, but the pro-domain can be actively displaced from the complex by follistatin. Our high-resolution structures of pro-activin A share features seen in the pro-TGF-β1 and pro-BMP-9 structures, but reveal a new oligomeric arrangement, with a domain-swapped, cross-armed conformation for the protomers in the dimeric protein. Activins are members of the TGF-β family of growth factors that are processed from precursors into the mature proteins. Here, the authors use structural biology and biochemistry to examine the protein domain organisation and gain insights into the activation of pro-activin A.
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Affiliation(s)
- Xuelu Wang
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Gerhard Fischer
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, UK
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10
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Zhu J, Mishra RK, Schiltz GE, Makanji Y, Scheidt KA, Mazar AP, Woodruff TK. Virtual High-Throughput Screening To Identify Novel Activin Antagonists. J Med Chem 2015; 58:5637-48. [PMID: 26098096 DOI: 10.1021/acs.jmedchem.5b00753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Activin belongs to the TGFβ superfamily, which is associated with several disease conditions, including cancer-related cachexia, preterm labor with delivery, and osteoporosis. Targeting activin and its related signaling pathways holds promise as a therapeutic approach to these diseases. A small-molecule ligand-binding groove was identified in the interface between the two activin βA subunits and was used for a virtual high-throughput in silico screening of the ZINC database to identify hits. Thirty-nine compounds without significant toxicity were tested in two well-established activin assays: FSHβ transcription and HepG2 cell apoptosis. This screening workflow resulted in two lead compounds: NUCC-474 and NUCC-555. These potential activin antagonists were then shown to inhibit activin A-mediated cell proliferation in ex vivo ovary cultures. In vivo testing showed that our most potent compound (NUCC-555) caused a dose-dependent decrease in FSH levels in ovariectomized mice. The Blitz competition binding assay confirmed target binding of NUCC-555 to the activin A:ActRII that disrupts the activin A:ActRII complex's binding with ALK4-ECD-Fc in a dose-dependent manner. The NUCC-555 also specifically binds to activin A compared with other TGFβ superfamily member myostatin (GDF8). These data demonstrate a new in silico-based strategy for identifying small-molecule activin antagonists. Our approach is the first to identify a first-in-class small-molecule antagonist of activin binding to ALK4, which opens a completely new approach to inhibiting the activity of TGFβ receptor superfamily members. in addition, the lead compound can serve as a starting point for lead optimization toward the goal of a compound that may be effective in activin-mediated diseases.
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Affiliation(s)
- Jie Zhu
- †Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 303 East Superior Street, Lurie 10-250, Chicago, Illinois 60611, United States.,‡Center for Reproductive Science, Northwestern University, Evanston, Illinois 60208, United States
| | - Rama K Mishra
- §Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Gary E Schiltz
- §Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Yogeshwar Makanji
- †Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 303 East Superior Street, Lurie 10-250, Chicago, Illinois 60611, United States
| | - Karl A Scheidt
- §Center for Molecular Innovation and Drug Discovery, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,⊥Department of Chemistry, Northwestern University, Evanston, 60208, Illinois, United States.,∥Department of Pharmacology, Northwestern University, Chicago, Illinois 60611, United States
| | - Andrew P Mazar
- ∥Department of Pharmacology, Northwestern University, Chicago, Illinois 60611, United States.,□Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208, United States
| | - Teresa K Woodruff
- †Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 303 East Superior Street, Lurie 10-250, Chicago, Illinois 60611, United States.,‡Center for Reproductive Science, Northwestern University, Evanston, Illinois 60208, United States.,□Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, Illinois 60208, United States
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Development of novel activin-targeted therapeutics. Mol Ther 2014; 23:434-44. [PMID: 25399825 DOI: 10.1038/mt.2014.221] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/09/2014] [Indexed: 01/07/2023] Open
Abstract
Soluble activin type II receptors (ActRIIA/ActRIIB), via binding to diverse TGF-β proteins, can increase muscle and bone mass, correct anemia or protect against diet-induced obesity. While exciting, these multiple actions of soluble ActRIIA/IIB limit their therapeutic potential and highlight the need for new reagents that target specific ActRIIA/IIB ligands. Here, we modified the activin A and activin B prodomains, regions required for mature growth factor synthesis, to generate specific activin antagonists. Initially, the prodomains were fused to the Fc region of mouse IgG2A antibody and, subsequently, "fastener" residues (Lys(45), Tyr(96), His(97), and Ala(98); activin A numbering) that confer latency to other TGF-β proteins were incorporated. For the activin A prodomain, these modifications generated a reagent that potently (IC(50) 5 nmol/l) and specifically inhibited activin A signaling in vitro, and activin A-induced muscle wasting in vivo. Interestingly, the modified activin B prodomain inhibited both activin A and B signaling in vitro (IC(50) ~2 nmol/l) and in vivo, suggesting it could serve as a general activin antagonist. Importantly, unlike soluble ActRIIA/IIB, the modified prodomains did not inhibit myostatin or GDF-11 activity. To underscore the therapeutic utility of specifically antagonising activin signaling, we demonstrate that the modified activin prodomains promote significant increases in muscle mass.
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Chen JL, Walton KL, Winbanks CE, Murphy KT, Thomson RE, Makanji Y, Qian H, Lynch GS, Harrison CA, Gregorevic P. Elevated expression of activins promotes muscle wasting and cachexia. FASEB J 2013; 28:1711-23. [PMID: 24378873 DOI: 10.1096/fj.13-245894] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In models of cancer cachexia, inhibiting type IIB activin receptors (ActRIIBs) reverse muscle wasting and prolongs survival, even with continued tumor growth. ActRIIB mediates signaling of numerous TGF-β proteins; of these, we demonstrate that activins are the most potent negative regulators of muscle mass. To determine whether activin signaling in the absence of tumor-derived factors induces cachexia, we used recombinant serotype 6 adeno-associated virus (rAAV6) vectors to increase circulating activin A levels in C57BL/6 mice. While mice injected with control vector gained ~10% of their starting body mass (3.8±0.4 g) over 10 wk, mice injected with increasing doses of rAAV6:activin A exhibited weight loss in a dose-dependent manner, to a maximum of -12.4% (-4.2±1.1 g). These reductions in body mass in rAAV6:activin-injected mice correlated inversely with elevated serum activin A levels (7- to 24-fold). Mechanistically, we show that activin A reduces muscle mass and function by stimulating the ActRIIB pathway, leading to deleterious consequences, including increased transcription of atrophy-related ubiquitin ligases, decreased Akt/mTOR-mediated protein synthesis, and a profibrotic response. Critically, we demonstrate that the muscle wasting and fibrosis that ensues in response to excessive activin levels is fully reversible. These findings highlight the therapeutic potential of targeting activins in cachexia.
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Affiliation(s)
- Justin L Chen
- 2Baker IDI Heart and Diabetes Institute, P.O. Box 6492, St. Kilda Rd. Central, Melbourne 8008, Australia.
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Marino FE, Risbridger G, Gold E. The therapeutic potential of blocking the activin signalling pathway. Cytokine Growth Factor Rev 2013; 24:477-84. [DOI: 10.1016/j.cytogfr.2013.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/29/2013] [Accepted: 04/30/2013] [Indexed: 12/24/2022]
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Hedger MP, de Kretser DM. The activins and their binding protein, follistatin-Diagnostic and therapeutic targets in inflammatory disease and fibrosis. Cytokine Growth Factor Rev 2013; 24:285-95. [PMID: 23541927 DOI: 10.1016/j.cytogfr.2013.03.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 03/05/2013] [Indexed: 02/05/2023]
Abstract
The activins, as members of the transforming growth factor-β superfamily, are pleiotrophic regulators of cell development and function, including cells of the myeloid and lymphoid lineages. Clinical and animal studies have shown that activin levels increase in both acute and chronic inflammation, and are frequently indicators of disease severity. Moreover, inhibition of activin action can reduce inflammation, damage, fibrosis and morbidity/mortality in various disease models. Consequently, activin A and, more recently, activin B are emerging as important diagnostic tools and therapeutic targets in inflammatory and fibrotic diseases. Activin antagonists such as follistatin, an endogenous activin-binding protein, offer considerable promise as therapies in conditions as diverse as sepsis, liver fibrosis, acute lung injury, asthma, wound healing and ischaemia-reperfusion injury.
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Affiliation(s)
- M P Hedger
- Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia.
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Fields SZ, Parshad S, Anne M, Raftopoulos H, Alexander MJ, Sherman ML, Laadem A, Sung V, Terpos E. Activin receptor antagonists for cancer-related anemia and bone disease. Expert Opin Investig Drugs 2012; 22:87-101. [PMID: 23127248 DOI: 10.1517/13543784.2013.738666] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Antagonists of activin receptor signaling may be beneficial for cancer-related anemia and bone disease caused by malignancies such as multiple myeloma and solid tumors. AREAS COVERED We review evidence of dysregulated signaling by activin receptor pathways in anemia, myeloma-associated osteolysis, and metastatic bone disease, as well as potential involvement in carcinogenesis. We then review properties of activin receptor antagonists in clinical development. EXPERT OPINION Sotatercept is a novel receptor fusion protein that functions as a soluble trap to sequester ligands of activin receptor type IIA (ActRIIA). Preclinically, the murine version of sotatercept increased red blood cells (RBC) in a model of chemotherapy-induced anemia, inhibited tumor growth and metastasis, and exerted anabolic effects on bone in diverse models of multiple myeloma. Clinically, sotatercept increases RBC markedly in healthy volunteers and patients with multiple myeloma. With a rapid onset of action differing from erythropoietin, sotatercept is in clinical development as a potential first-in-class therapeutic for cancer-related anemia, including those characterized by ineffective erythropoiesis as in myelodysplastic syndromes. Anabolic bone activity in early clinical studies and potential antitumor effects make sotatercept a promising therapeutic candidate for multiple myeloma and malignant bone diseases. Antitumor activity has been observed preclinically with small-molecule inhibitors of transforming growth factor-β receptor type I (ALK5) that also antagonize the closely related activin receptors ALK4 and ALK7. LY-2157299, the first such inhibitor to enter clinical studies, has shown an acceptable safety profile so far in patients with advanced cancer. Together, these data identify activin receptor antagonists as attractive therapeutic candidates for multiple diseases.
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Affiliation(s)
- Scott Z Fields
- Monter Cancer Center, Hofstra North Shore-LIJ School of Medicine, Lake Success, NY, USA
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Antsiferova M, Werner S. The bright and the dark sides of activin in wound healing and cancer. J Cell Sci 2012; 125:3929-37. [PMID: 22991378 DOI: 10.1242/jcs.094789] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Activin was initially described as a protein that stimulates release of follicle stimulating hormone from the pituitary, and it is well known for its important roles in different reproductive functions. In recent years, this multifunctional factor has attracted the attention of researchers in other fields, as new functions of activin in angiogenesis, inflammation, immunity, fibrosis and cancer have been discovered. Studies from our laboratory have identified activin as a crucial regulator of wound healing and skin carcinogenesis. On the one hand, it strongly accelerates the healing process of skin wounds but, on the other hand, it enhances scar formation and the susceptibility to skin tumorigenesis. Finally, results from several laboratories have revealed that activin enhances tumour formation and/or progression in some other organs, in particular through its effect on the tumour microenvironment, and that it also promotes cancer-induced bone disruption and muscle wasting. These findings provide the basis for the use of activin or its downstream targets for the improvement of impaired wound healing, and of activin antagonists for the prevention and treatment of fibrosis and of malignant tumours that overexpress activin. Here, we summarize the previously described roles of activin in wound healing and scar formation and discuss functional studies that revealed different functions of activin in the pathogenesis of cancer. The relevance of these findings for clinical applications will be highlighted.
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Affiliation(s)
- Maria Antsiferova
- Department of Biology, Institute of Molecular Health Sciences, ETH Honggerberg, HPL E12, 8093, Zurich, Switzerland.
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McIntosh CJ, Lawrence S, Smith P, Juengel JL, McNatty KP. Active immunization against the proregions of GDF9 or BMP15 alters ovulation rate and litter size in mice. Reproduction 2012; 143:195-201. [DOI: 10.1530/rep-11-0336] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The transforming growth factor β (TGFB) superfamily proteins bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9), are essential for mammalian fertility. Recent in vitro evidence suggests that the proregions of mouse BMP15 and GDF9 interact with their mature proteins after secretion. In this study, we have actively immunized mice against these proregions to test the potential in vivo roles on fertility. Mice were immunized with either N- or C-terminus proregion peptides of BMP15 or GDF9, or a full-length GDF9 proregion protein, each conjugated to keyhole limpet hemocyanin (KLH). For each immunization group, ovaries were collected from ten mice for histology after immunization, while a further 20 mice were allowed to breed and litter sizes were counted. To link the ovulation and fertility data of these two experimental end points, mice were joined during the time period identified by histology as being the ovulatory period resulting in to the corpora lutea (CL) counted. Antibody titers in sera increased throughout the study period, with no cross-reactivity observed between BMP15 and GDF9 sera and antigens. Compared with KLH controls, mice immunized with the N-terminus BMP15 proregion peptide had ovaries with fewer CL (P<0.05) and produced smaller litters (P<0.05). In contrast, mice immunized with the full-length GDF9 proregion not only had more CL (P<0.01) but also had significantly smaller litter sizes (P<0.01). None of the treatments affected the number of antral follicles per ovary. These findings are consistent with the hypothesis that the proregions of BMP15 and GDF9, after secretion by the oocyte, have physiologically important roles in regulating ovulation rate and litter size in mice.
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Nielsen HC, Torday JS. A new compass for activin research--a triumph for systems biology. Endocrinology 2011; 152:3587-8. [PMID: 21937748 PMCID: PMC3176645 DOI: 10.1210/en.2011-1620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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