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Lv Y, Qi J, Babon JJ, Cao L, Fan G, Lang J, Zhang J, Mi P, Kobe B, Wang F. The JAK-STAT pathway: from structural biology to cytokine engineering. Signal Transduct Target Ther 2024; 9:221. [PMID: 39169031 DOI: 10.1038/s41392-024-01934-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/12/2024] [Accepted: 07/16/2024] [Indexed: 08/23/2024] Open
Abstract
The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway serves as a paradigm for signal transduction from the extracellular environment to the nucleus. It plays a pivotal role in physiological functions, such as hematopoiesis, immune balance, tissue homeostasis, and surveillance against tumors. Dysregulation of this pathway may lead to various disease conditions such as immune deficiencies, autoimmune diseases, hematologic disorders, and cancer. Due to its critical role in maintaining human health and involvement in disease, extensive studies have been conducted on this pathway, ranging from basic research to medical applications. Advances in the structural biology of this pathway have enabled us to gain insights into how the signaling cascade operates at the molecular level, laying the groundwork for therapeutic development targeting this pathway. Various strategies have been developed to restore its normal function, with promising therapeutic potential. Enhanced comprehension of these molecular mechanisms, combined with advances in protein engineering methodologies, has allowed us to engineer cytokines with tailored properties for targeted therapeutic applications, thereby enhancing their efficiency and safety. In this review, we outline the structural basis that governs key nodes in this pathway, offering a comprehensive overview of the signal transduction process. Furthermore, we explore recent advances in cytokine engineering for therapeutic development in this pathway.
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Affiliation(s)
- You Lv
- Center for Molecular Biosciences and Non-communicable Diseases Research, Xi'an University of Science and Technology, Xi'an, Shaanxi, 710054, China
- Xi'an Amazinggene Co., Ltd, Xi'an, Shaanxi, 710026, China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100080, China
| | - Jeffrey J Babon
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Longxing Cao
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
| | - Guohuang Fan
- Immunophage Biotech Co., Ltd, No. 10 Lv Zhou Huan Road, Shanghai, 201112, China
| | - Jiajia Lang
- School of Pharmaceutical Science, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Jin Zhang
- Xi'an Amazinggene Co., Ltd, Xi'an, Shaanxi, 710026, China
| | - Pengbing Mi
- School of Pharmaceutical Science, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China.
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland, 4072, Australia.
| | - Faming Wang
- Center for Molecular Biosciences and Non-communicable Diseases Research, Xi'an University of Science and Technology, Xi'an, Shaanxi, 710054, China.
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2
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Mravic M, He L, Kratochvil HT, Hu H, Nick SE, Bai W, Edwards A, Jo H, Wu Y, DiMaio D, DeGrado WF. De novo-designed transmembrane proteins bind and regulate a cytokine receptor. Nat Chem Biol 2024; 20:751-760. [PMID: 38480980 PMCID: PMC11142920 DOI: 10.1038/s41589-024-01562-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 01/25/2024] [Indexed: 05/30/2024]
Abstract
Transmembrane (TM) domains as simple as a single span can perform complex biological functions using entirely lipid-embedded chemical features. Computational design has the potential to generate custom tool molecules directly targeting membrane proteins at their functional TM regions. Thus far, designed TM domain-targeting agents have been limited to mimicking the binding modes and motifs of natural TM interaction partners. Here, we demonstrate the design of de novo TM proteins targeting the erythropoietin receptor (EpoR) TM domain in a custom binding topology competitive with receptor homodimerization. The TM proteins expressed in mammalian cells complex with EpoR and inhibit erythropoietin-induced cell proliferation. In vitro, the synthetic TM domain complex outcompetes EpoR homodimerization. Structural characterization reveals that the complex involves the intended amino acids and agrees with our designed molecular model of antiparallel TM helices at 1:1 stoichiometry. Thus, membrane protein TM regions can now be targeted in custom-designed topologies.
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Affiliation(s)
- Marco Mravic
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA.
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.
| | - Li He
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Huong T Kratochvil
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA
- Department of Chemistry, University of North Carolina Chapel Hill, Chapel Hill, NC, USA
| | - Hailin Hu
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA
- School of Medicine, Tsinghua University, Beijing, China
| | - Sarah E Nick
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA
| | - Weiya Bai
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Anne Edwards
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA
| | - Yibing Wu
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA
| | - Daniel DiMaio
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, USA.
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA.
- Yale Cancer Center, New Haven, CT, USA.
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, CA, USA.
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Metallinou C, Staneloudi C, Nikolettos K, Asimakopoulos B. NGF, EPO, and IGF-1 in the Male Reproductive System. J Clin Med 2024; 13:2918. [PMID: 38792459 PMCID: PMC11122040 DOI: 10.3390/jcm13102918] [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: 02/19/2024] [Revised: 04/09/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024] Open
Abstract
Several studies have demonstrated interesting results considering the implication of three growth factors (GFs), namely nerve growth factor (NGF), erythropoietin (EPO), and the insulin-like growth factor-I (IGF-1) in the physiology of male reproductive functions. This review provides insights into the effects of NGF, EPO, and IGF-1 on the male reproductive system, emphasizing mainly their effects on sperm motility and vitality. In the male reproductive system, the expression pattern of the NGF system varies according to the species and testicular development, playing a crucial role in morphogenesis and spermatogenesis. In humans, it seems that NGF positively affects sperm motility parameters and NGF supplementation in cryopreservation media improves post-thaw sperm motility. In animals, EPO is found in various male reproductive tissues, and in humans, the protein is present in seminal plasma and testicular germ cells. EPO receptors have been discovered in the plasma membrane of human spermatozoa, suggesting potential roles in sperm motility and vitality. In humans, IGF-1 is expressed mainly in Sertoli cells and is present in seminal plasma, contributing to cell development and the maturation of spermatozoa. IGF-1 seems to modulate sperm motility, and treatment with IGF-1 has a positive effect on sperm motility and vitality. Furthermore, lower levels of NGF or IGF-1 in seminal plasma are associated with infertility. Understanding the mechanisms of actions of these GFs in the male reproductive system may improve the outcome of sperm processing techniques.
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Affiliation(s)
- Chryssa Metallinou
- Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Democritus University of Thrace, 69100 Alexandroupolis, Greece; (C.M.); (K.N.)
| | - Chrysovalanto Staneloudi
- Laboratory of Exercise Physiology and Biochemistry, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Konstantinos Nikolettos
- Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Democritus University of Thrace, 69100 Alexandroupolis, Greece; (C.M.); (K.N.)
| | - Byron Asimakopoulos
- Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Democritus University of Thrace, 69100 Alexandroupolis, Greece; (C.M.); (K.N.)
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Sarson-Lawrence KTG, Hardy JM, Iaria J, Stockwell D, Behrens K, Saiyed T, Tan C, Jebeli L, Scott NE, Dite TA, Nicola NA, Leis AP, Babon JJ, Kershaw NJ. Cryo-EM structure of the extracellular domain of murine Thrombopoietin Receptor in complex with Thrombopoietin. Nat Commun 2024; 15:1135. [PMID: 38326297 PMCID: PMC10850085 DOI: 10.1038/s41467-024-45356-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 01/19/2024] [Indexed: 02/09/2024] Open
Abstract
Thrombopoietin (Tpo) is the primary regulator of megakaryocyte and platelet numbers and is required for haematopoetic stem cell maintenance. Tpo functions by binding its receptor (TpoR, a homodimeric Class I cytokine receptor) and initiating cell proliferation or differentiation. Here we characterise the murine Tpo:TpoR signalling complex biochemically and structurally, using cryo-electron microscopy. Tpo uses opposing surfaces to recruit two copies of receptor, forming a 1:2 complex. Although it binds to the same, membrane-distal site on both receptor chains, it does so with significantly different affinities and its highly glycosylated C-terminal domain is not required. In one receptor chain, a large insertion, unique to TpoR, forms a partially structured loop that contacts cytokine. Tpo binding induces the juxtaposition of the two receptor chains adjacent to the cell membrane. The therapeutic agent romiplostim also targets the cytokine-binding site and the characterisation presented here supports the future development of improved TpoR agonists.
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Affiliation(s)
- Kaiseal T G Sarson-Lawrence
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Joshua M Hardy
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
| | - Josephine Iaria
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Dina Stockwell
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Kira Behrens
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Tamanna Saiyed
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Cyrus Tan
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000, Victoria, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000, Victoria, Australia
| | - Toby A Dite
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Nicos A Nicola
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
| | - Andrew P Leis
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
| | - Jeffrey J Babon
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia.
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia.
| | - Nadia J Kershaw
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia.
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, Victoria, Australia.
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Mravic M, He L, Kratochvil H, Hu H, Nick SE, Bai W, Edwards A, Jo H, Wu Y, DiMaio D, DeGrado WF. Designed Transmembrane Proteins Inhibit the Erythropoietin Receptor in a Custom Binding Topology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.13.526773. [PMID: 36824741 PMCID: PMC9949092 DOI: 10.1101/2023.02.13.526773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Transmembrane (TM) domains as simple as a single span can perform complex biological functions using entirely lipid-embedded chemical features. Computational design has potential to generate custom tool molecules directly targeting membrane proteins at their functional TM regions. Thus far, designed TM domain-targeting agents have been limited to mimicking binding modes and motifs of natural TM interaction partners. Here, we demonstrate the design of de novo TM proteins targeting the erythropoietin receptor (EpoR) TM domain in a custom binding topology competitive with receptor homodimerization. The TM proteins expressed in mammalian cells complex with EpoR and inhibit erythropoietin-induced cell proliferation. In vitro, the synthetic TM domain complex outcompetes EpoR homodimerization. Structural characterization reveals that the complex involves the intended amino acids and agrees with our designed molecular model of antiparallel TM helices at 1:1 stoichiometry. Thus, membrane protein TM regions can now be targeted in custom designed topologies.
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6
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Roth S, Margulis M, Danielli A. Recent Advances in Rapid and Highly Sensitive Detection of Proteins and Specific DNA Sequences Using a Magnetic Modulation Biosensing System. SENSORS (BASEL, SWITZERLAND) 2022; 22:4497. [PMID: 35746278 PMCID: PMC9230956 DOI: 10.3390/s22124497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
In early disease stages, biomolecules of interest exist in very low concentrations, presenting a significant challenge for analytical devices and methods. Here, we provide a comprehensive overview of an innovative optical biosensing technology, termed magnetic modulation biosensing (MMB), its biomedical applications, and its ongoing development. In MMB, magnetic beads are attached to fluorescently labeled target molecules. A controlled magnetic force aggregates the magnetic beads and transports them in and out of an excitation laser beam, generating a periodic fluorescent signal that is detected and demodulated. MMB applications include rapid and highly sensitive detection of specific nucleic acid sequences, antibodies, proteins, and protein interactions. Compared with other established analytical methodologies, MMB provides improved sensitivity, shorter processing time, and simpler protocols.
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Khafagi AT, Yehia MA, Helmy AK, Hassan W, Abdelhakim N. Effect of Erythropoietin-stimulating agent on uremic neuropathy in hemodialysis patients: a single-center open-label prospective study. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2022. [DOI: 10.1186/s41983-022-00477-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Uremic neuropathy is a distal sensorimotor polyneuropathy caused by uremic toxins; its severity is correlated with the degree of renal insufficiency. Erythropoietin (EPO) and erythropoietin receptors (EpoR) are produced in the peripheral nervous system. This is a single-center open-label prospective study was designed to investigate the possible effect of erythropoietin-stimulating agents (ESAs) on uremic neuropathy. Twenty-four newly diagnosed end-stage kidney disease (ESKD) patients were selected, clinical assessment, laboratory, and neurophysiological study were done at 1 and follow-up after 3 months. Patients were divided into two groups (group A received ESA and group B did not receive ESA).
Results
Eighteen patients completed the study, eight patients (44.4%) did not have symptoms but had electrophysiological findings of neuropathy (subclinical neuropathy). After 3 months of hemodialysis, patients in group A showed improvement of some electrophysiological features (ulnar MNCV; P = 0.016).
Conclusions
The use of ESA may improve uremic neuropathy in patients with newly diagnosed ESKD who have been started on hemodialysis.
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Hessefort H, Gross A, Seeleithner S, Hessefort M, Kirsch T, Perkams L, Bundgaard KO, Gottwald K, Rau D, Graf CGF, Rozanski E, Weidler S, Unverzagt C. Chemical and Enzymatic Synthesis of Sialylated Glycoforms of Human Erythropoietin. Angew Chem Int Ed Engl 2021; 60:25922-25932. [PMID: 34523784 PMCID: PMC9297946 DOI: 10.1002/anie.202110013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/31/2021] [Indexed: 01/15/2023]
Abstract
Recombinant human erythropoietin (EPO) is the main therapeutic glycoprotein for the treatment of anemia in cancer and kidney patients. The in‐vivo activity of EPO is carbohydrate‐dependent with the number of sialic acid residues regulating its circulatory half‐life. EPO carries three N‐glycans and thus obtaining pure glycoforms provides a major challenge. We have developed a robust and reproducible chemoenzymatic approach to glycoforms of EPO with and without sialic acids. EPO was assembled by sequential native chemical ligation of two peptide and three glycopeptide segments. The glycopeptides were obtained by pseudoproline‐assisted Lansbury aspartylation. Enzymatic introduction of the sialic acids was readily accomplished at the level of the glycopeptide segments but even more efficiently on the refolded glycoprotein. Biological recognition of the synthetic EPOs was shown by formation of 1:1 complexes with recombinant EPO receptor.
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Affiliation(s)
- Hendrik Hessefort
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Angelina Gross
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Simone Seeleithner
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Markus Hessefort
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Tanja Kirsch
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Lukas Perkams
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Klaus Ole Bundgaard
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Karen Gottwald
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - David Rau
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | | | - Elisabeth Rozanski
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Sascha Weidler
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
| | - Carlo Unverzagt
- University of Bayreuth, Bioorganic Chemistry, Universitätsstraße 30, 95447, Bayreuth, Germany
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Hessefort H, Gross A, Seeleithner S, Hessefort M, Kirsch T, Perkams L, Bundgaard KO, Gottwald K, Rau D, Graf CGF, Rozanski E, Weidler S, Unverzagt C. Chemical and Enzymatic Synthesis of Sialylated Glycoforms of Human Erythropoietin. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hendrik Hessefort
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Angelina Gross
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Simone Seeleithner
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Markus Hessefort
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Tanja Kirsch
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Lukas Perkams
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Klaus Ole Bundgaard
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Karen Gottwald
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - David Rau
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | | | - Elisabeth Rozanski
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Sascha Weidler
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
| | - Carlo Unverzagt
- University of Bayreuth Bioorganic Chemistry Universitätsstraße 30 95447 Bayreuth Germany
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A Novel Plant-Produced Asialo-rhuEPO Protects Brain from Ischemic Damage Without Erythropoietic Action. Transl Stroke Res 2021; 13:338-354. [PMID: 34553324 PMCID: PMC10068895 DOI: 10.1007/s12975-021-00943-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/09/2021] [Accepted: 09/03/2021] [Indexed: 12/14/2022]
Abstract
Mammalian cell-produced recombinant human erythropoietin (rhuEPOM) has been shown to be a multimodal neuroprotectant targeting an array of key pathological mechanisms in experimental stroke models. However, the rhuEPOM clinical trials were terminated due to increased risk of thrombosis, largely ascribed to its erythropoietic function. We recently took advantage of a plant-based expression system lacking sialylation capacity to produce asialo-rhuEPOP, a rhuEPO derivative without sialic acid residues. In the present study, we proved that asialo-rhuEPOP is non-erythropoietic by repeated intravenous injection (44 μg/kg bw) in mice showing no increase in hemoglobin levels and red blood cell counts, and confirmed that it is non-immunogenic by measuring humoral response after immunizing the mice. We demonstrate that it is neuroprotective in a cerebral ischemia and reperfusion (I/R) mouse model, exhibiting ~ 50% reduction in cerebral infarct volume and edema, and significant improvement in neurological deficits and histopathological outcome. Our studies further revealed that asialo-rhuEPOP, like rhuEPOM, displays pleiotropic neuroprotective effects, including restoring I/R-interrupted mitochondrial fission and fusion proteins, preventing I/R injury-induced increase in mitophagy and autophagy markers, and inhibiting apoptosis to benefit nerve cell survival. Most importantly, asialo-rhuEPOP lacking erythropoietic activity and immunogenicity holds great translational potential as a multimodal neuroprotectant for stroke treatment.
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11
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Asimakopoulos B, Tiptiri-Kourpeti A, Metalinou C. Erythropoitein Increases In Vitro Motility and Vitality of Human Spermatozoa. In Vivo 2021; 35:2669-2673. [PMID: 34410955 DOI: 10.21873/invivo.12550] [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: 05/12/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Erythropoietin and its receptor are expressed in the male reproductive system. Initial studies have shown that erythropoietin affects the motility of spermatozoa. The aim of the present study was to investigate the in vitro effect of erythropoietin in the motility and vitality of human spermatozoa. MATERIALS AND METHODS Forty-three semen samples, obtained after 2-4 days of abstinence from sex, were analyzed and processed using density gradient centrifugation. Aliquots containing one million of spermatozoa were treated with either erythropoietin, at concentrations of 10 and 100 mIU/μl or standard culture medium for one hour. RESULTS Progressive motility and vitality of spermatozoa significantly increased following treatment with erythropoietin. The effect was not dose-dependent. CONCLUSION The supplementation of culture medium with erythropoietin improves sperm processing in terms of vitality and motility. Future research should focus on the effects of erythropoietin on sperm capacitation as well as on the signal transduction pathways activated by erythropoietin and its receptor in spermatozoa.
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Affiliation(s)
- Byron Asimakopoulos
- Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Democritus University of Thrace, Alexandroupolis, Greece
| | - Aggeliki Tiptiri-Kourpeti
- Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Democritus University of Thrace, Alexandroupolis, Greece
| | - Chryssa Metalinou
- Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Democritus University of Thrace, Alexandroupolis, Greece
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12
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Araki D, Alvarado LJ, Huntsman HD, Smith RH, Larochelle A. IFN-γ directly inhibits the activity of erythropoietin in human erythroid progenitors. Blood Cells Mol Dis 2020; 85:102488. [PMID: 32889151 DOI: 10.1016/j.bcmd.2020.102488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Daisuke Araki
- National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Luigi J Alvarado
- National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Heather D Huntsman
- National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Richard H Smith
- National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Andre Larochelle
- National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
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13
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Comparison of different immunoassay methods to detect human anti-drug antibody using the WHO erythropoietin antibody reference panel for analytes. J Immunol Methods 2017; 452:73-77. [PMID: 28970009 DOI: 10.1016/j.jim.2017.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 01/20/2023]
Abstract
Development of an appropriate assay to detect anti-drug antibody (ADA) is important for assessing immunogenicity to therapeutic protein products. However, characterizing ADA assay methods is difficult because human ADA as a reference standard is not available in most cases. We compared the analytical performance of three ligand-binding assay methods for ADA, namely, surface plasmon resonance (SPR), electrochemiluminescence (ECL), and biolayer interferometry (BLI) methods, by using the anti-erythropoietin (EPO) monoclonal antibody reference panel developed by the World Health Organization (WHO) in 2015. Dose-dependent binding responses were observed for all nine anti-EPO antibodies in the anti-EPO panel by the SPR and BLI methods. In contrast, the ECL method did not clearly detect binding of low-affinity anti-EPO antibodies. Regarding IgG2 and IgM antibodies derived from the same clone, IgG2 exhibited a higher binding response in the SPR assay, whereas the IgM binding response was higher than that of IgG2 in the ECL assay. In the case of the BLI method, there was no consistent pattern observed in the binding responses of IgG2 or IgM. Results of the anti-EPO antibody reference panel, which contains a variety of monoclonal antibodies, indicated that the ability to detect ADAs differed among these assay methods. Therefore, with ligand-binding assays, differences in assay platforms can affect the sensitivity and other characteristics of assays to detect ADAs. These results show that understanding the analytical performance of ADA assays is important for an appropriate assessment of immunogenicity. Our study also indicated the benefits of using the established human ADA reference panel to assess the assay methods for ADA detection.
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14
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Uversky VN, Redwan EM. Erythropoietin and co.: intrinsic structure and functional disorder. MOLECULAR BIOSYSTEMS 2017; 13:56-72. [PMID: 27833947 DOI: 10.1039/c6mb00657d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Erythropoietin (Epo) is a heavily glycosylated protein, with its main function being related to erythropoiesis, where it controls red blood cell production via interaction with the Epo receptor (EpoR). It also plays a number of important roles in various hormonal, growth factor, and cytokine pathways. These roles are defined by Epo partners, such as the homodimeric (EpoR)2 receptor, the heterodimeric EpoR/βCR receptor and hypoxia inducing factor (HIF). Although the main structural features of both Epo and EpoR are conserved in vertebrates, the secretion sites of Epo in mammals are different from those in other vertebrates. Both biosynthetic and synthetic analogues of this protein are available on the market. Several side effects, such as pure red cells aplaisa, increase the rate of cancer-related death in patients treated with recombinant Epo. The multifunctionality of Epo and the ability of this protein to serve as a hormone, a cytokine, and a growth factor suggest the presence of functional disorder, which is a typical "structural" feature of moonlighting proteins. The goal of this article is to evaluate the roles of intrinsic disorder in the functions of Epo and its primary interactors, EpoR, βCR, and HIF-1α.
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Affiliation(s)
- Vladimir N Uversky
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia. and Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia and Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Elrashdy M Redwan
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia. and Therapeutic and Protective Proteins Laboratory, Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications, New Borg EL-Arab 21934, Alexandria, Egypt
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15
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Erythropoietin-Mediated Regulation of Central Respiratory Command. VITAMINS AND HORMONES 2017. [PMID: 28629514 DOI: 10.1016/bs.vh.2017.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Erythropoietin (Epo) is a cytokine expressed throughout the body, including in the central nervous system where it can act as a breathing modulator in the central respiratory network. In vitro, Epo allows maintaining the activity of respiratory neurons during acute hypoxia, resulting in inhibition of the hypoxia-induced rhythm depression. In vivo, Epo action on the central respiratory command results in enhancement of the acute hypoxic ventilatory response, allowing a better oxygenation of the body by improvement of gases exchanges in the lungs. Importantly, this effect of Epo is age-dependent, being observed at adulthood and at both early and late postnatal ages, but not at middle postnatal ages, when an important setup of the central respiratory command occurs. Epo regulation of the central respiratory command involves at least two intracellular signaling pathways, PI3K-Akt and MEK-ERK pathways. However, the exact mechanism underlying the action of Epo on the central respiratory control remains to be deciphered, as well as the exact cell types and nuclei involved in this control. Epo-mediated effect on the central respiratory command is regulated by several factors, including hypoxia, sex hormones, and an endogen antagonist. Although more knowledge is needed before reaching the clinical trial step, Epo seems to be a promising therapeutic treatment, notably against newborn breathing disorders.
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16
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Corbett MSP, Poger D, Mark AE. Revisiting the scissor-like mechanism of activation for the erythropoietin receptor. FEBS Lett 2016; 590:3083-8. [PMID: 27490140 DOI: 10.1002/1873-3468.12340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 07/27/2016] [Accepted: 07/28/2016] [Indexed: 01/28/2023]
Abstract
An interpretation of alternative crystal structures of the erythropoietin receptor, with and without ligand, led to the proposal of a scissor-like mechanism of activation. This model has been propagated in the literature and is still being used to interpret crystal structures of related type-I cytokine receptors. Here, we assess whether the model remains compatible with current knowledge on the family of type-I cytokine receptors, and consider whether the model, as initially presented, is truly supported by the crystal structures on which it was originally based.
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Affiliation(s)
- Michael S P Corbett
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - David Poger
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia.
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia.
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17
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Wadhwa M, Mytych DT, Bird C, Barger T, Dougall T, Han H, Rigsby P, Kromminga A, Thorpe R. Establishment of the first WHO Erythropoietin antibody reference panel: Report of an international collaborative study. J Immunol Methods 2016; 435:32-42. [DOI: 10.1016/j.jim.2016.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/25/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
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18
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Quality and Batch-to-Batch Consistency of Original and Biosimilar Epoetin Products. J Pharm Sci 2016; 105:542-550. [DOI: 10.1016/j.xphs.2015.10.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 09/24/2015] [Accepted: 10/09/2015] [Indexed: 12/19/2022]
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19
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Jenni S, Goyal Y, von Grotthuss M, Shvartsman SY, Klein DE. Structural Basis of Neurohormone Perception by the Receptor Tyrosine Kinase Torso. Mol Cell 2015; 60:941-52. [PMID: 26698662 DOI: 10.1016/j.molcel.2015.10.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 09/17/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
Abstract
In insects, brain-derived Prothoracicotropic hormone (PTTH) activates the receptor tyrosine kinase (RTK) Torso to initiate metamorphosis through the release of ecdysone. We have determined the crystal structure of silkworm PTTH in complex with the ligand-binding region of Torso. Here we show that ligand-induced Torso dimerization results from the sequential and negatively cooperative formation of asymmetric heterotetramers. Mathematical modeling of receptor activation based upon our biophysical studies shows that ligand pulses are "buffered" at low receptor levels, leading to a sustained signal. By contrast, high levels of Torso develop the signal intensity and duration of a noncooperative system. We propose that this may allow Torso to coordinate widely different functions from a single ligand by tuning receptor levels. Phylogenic analysis indicates that Torso is found outside arthropods, including human parasitic roundworms. Together, our findings provide mechanistic insight into how this receptor system, with roles in embryonic and adult development, is regulated.
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Affiliation(s)
- Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Yogesh Goyal
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | | | - Stanislav Y Shvartsman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Daryl E Klein
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Division of Molecular Medicine, Children's Hospital, Boston, MA 02115, USA.
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20
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Hatayama K, Ide T. Engineering of erythropoietin receptor for use as an affinity ligand. Protein Expr Purif 2015; 111:1-8. [DOI: 10.1016/j.pep.2015.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
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21
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Velazquez-Campoy A, Leavitt SA, Freire E. Characterization of protein-protein interactions by isothermal titration calorimetry. Methods Mol Biol 2015; 1278:183-204. [PMID: 25859950 DOI: 10.1007/978-1-4939-2425-7_11] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The analysis of protein-protein interactions has attracted the attention of many researchers from both a fundamental point of view and a practical point of view. From a fundamental point of view, the development of an understanding of the signaling events triggered by the interaction of two or more proteins provides key information to elucidate the functioning of many cell processes. From a practical point of view, understanding protein-protein interactions at a quantitative level provides the foundation for the development of antagonists or agonists of those interactions. Isothermal Titration Calorimetry (ITC) is the only technique with the capability of measuring not only binding affinity but the enthalpic and entropic components that define affinity. Over the years, isothermal titration calorimeters have evolved in sensitivity and accuracy. Today, TA Instruments and MicroCal market instruments with the performance required to evaluate protein-protein interactions. In this methods paper, we describe general procedures to analyze heterodimeric (porcine pancreatic trypsin binding to soybean trypsin inhibitor) and homodimeric (bovine pancreatic α-chymotrypsin) protein associations by ITC.
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Affiliation(s)
- Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI, Universidad de Zaragoza, Zaragoza, Spain,
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22
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Debeljak N, Solár P, Sytkowski AJ. Erythropoietin and cancer: the unintended consequences of anemia correction. Front Immunol 2014; 5:563. [PMID: 25426117 PMCID: PMC4227521 DOI: 10.3389/fimmu.2014.00563] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/22/2014] [Indexed: 01/12/2023] Open
Abstract
Until 1990, erythropoietin (EPO) was considered to have a single biological purpose and action, the stimulation of red blood cell growth and differentiation. Slowly, scientific and medical opinion evolved, beginning with the discovery of an effect on endothelial cell growth in vitro and the identification of EPO receptors (EPORs) on neuronal cells. We now know that EPO is a pleiotropic growth factor that exhibits an anti-apoptotic action on numerous cells and tissues, including malignant ones. In this article, we present a short discussion of EPO, receptors involved in EPO signal transduction, and their action on non-hematopoietic cells. This is followed by a more detailed presentation of both pre-clinical and clinical data that demonstrate EPO’s action on cancer cells, as well as tumor angiogenesis and lymphangiogenesis. Clinical trials with reported adverse effects of chronic erythropoiesis-stimulating agents (ESAs) treatment as well as clinical studies exploring the prognostic significance of EPO and EPOR expression in cancer patients are reviewed. Finally, we address the use of EPO and other ESAs in cancer patients.
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Affiliation(s)
- Nataša Debeljak
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana , Ljubljana , Slovenia
| | - Peter Solár
- Department of Cell and Molecular Biology, Institute of Biology and Ecology, Faculty of Sciences, Pavol Jozef Šafárik University , Košice , Slovakia
| | - Arthur J Sytkowski
- Oncology Therapeutic Area, Quintiles Transnational , Arlington, MA , USA
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23
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Clinical pharmacokinetics and pharmacodynamics of erythropoiesis-stimulating agents. Clin Pharmacokinet 2014; 52:1063-83. [PMID: 23912564 DOI: 10.1007/s40262-013-0098-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cloning of the EPO gene in the early 1980s allowed for the development of recombinant erythropoietins and analogues [erythropoiesis-stimulating agents (ESAs)], offering an alternative to transfusion as a method of raising haemoglobin (Hb) levels, which have been used for more than 20 years to treat anaemia in millions of anaemic patients. There are now a number of ESAs available worldwide for the treatment of anaemia, approved for different routes of administration (intravenous and subcutaneous) and dosing intervals (three times weekly, weekly, biweekly and monthly). In this review, we discuss the pharmacokinetic characteristics, including absorption, distribution and elimination processes, across the different ESAs. Incomplete and slow lymphatic absorption, with limited extravascular distribution, and minor contributions of the target-mediated drug disposition to the overall elimination are the common characteristics across the marketed ESA. Additionally, we assess the similarities and differences of ESAs related to pharmacodynamics in the context of the different biomarkers used to monitor the magnitude and duration of the effect, and introduce the concept of the minimum effective concentration of the ESA. The relationship between the minimum effective concentration and the half-life suggests that the time during which drug concentrations are above the minimum effective concentration is the main determinant of ESA efficacy in increasing Hb levels. The tolerance phenomenon and its physiological mechanism and implications for ESA dosing are discussed. Finally, the areas of future clinical pharmacology research are envisioned.
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24
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Van Roey K, Uyar B, Weatheritt RJ, Dinkel H, Seiler M, Budd A, Gibson TJ, Davey NE. Short Linear Motifs: Ubiquitous and Functionally Diverse Protein Interaction Modules Directing Cell Regulation. Chem Rev 2014; 114:6733-78. [DOI: 10.1021/cr400585q] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kim Van Roey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Robert J. Weatheritt
- MRC
Laboratory of Molecular Biology (LMB), Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Holger Dinkel
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Markus Seiler
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Aidan Budd
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J. Gibson
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Norman E. Davey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department
of Physiology, University of California, San Francisco, San Francisco, California 94143, United States
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25
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Del Vecchio L, Locatelli F. New treatment approaches in chronic kidney disease-associated anaemia. Expert Opin Biol Ther 2014; 14:687-96. [PMID: 24579747 DOI: 10.1517/14712598.2014.892577] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Erythropoiesis-stimulating agents (ESA) and iron are the main tools for treating anaemia associated with chronic kidney disease (CKD). Pharmaceutical research has focused on modified epoetins or different strategies to stimulate erythropoiesis with the idea of improving relative disadvantages of the molecules already available in the market. AREAS COVERED Following a literature search on PubMed using anaemia, haemoglobin, erythropoietin (EPO), hypoxia-inducible transcription factor (HIF) inhibitors and chronic kidney disease as keywords, we critically analysed new strategies for increasing erythropoiesis, looking in depth at their peculiar characteristics and possible advantages in the clinical setting. EXPERT OPINION In recent years the ESA market is facing a number of hurdles making it less appealing than before. Economic recession or stagnation has raised the need of sustainability of medical treatment. New treatments must bring clear benefits compared to existing drugs. In addition to this, ESA consumption has been progressively reduced, fearing possible risks of increased cardiovascular events especially when given at excessive doses. New drugs may also undergo premature stopping because of unexpected adverse reactions as for peginesatide. At present, the most promising approach to anaemia treatment in CKD patients is the manipulation of the HIF system. The regulation of activin A pathway is another option with good potential, also considering the additional advantage of increasing bone mass.
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Affiliation(s)
- Lucia Del Vecchio
- A Manzoni Hospital, Department of Nephrology, Dialysis, and Renal Transplant , Via dell'Eremo 9, 23900 Lecco , Italy
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26
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Moraga I, Spangler J, Mendoza JL, Garcia KC. Multifarious determinants of cytokine receptor signaling specificity. Adv Immunol 2014; 121:1-39. [PMID: 24388212 DOI: 10.1016/b978-0-12-800100-4.00001-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cytokines play crucial roles in regulating immune homeostasis. Two important characteristics of most cytokines are pleiotropy, defined as the ability of one cytokine to exhibit diverse functionalities, and redundancy, defined as the ability of multiple cytokines to exert overlapping activities. Identifying the determinants for unique cellular responses to cytokines in the face of shared receptor usage, pleiotropy, and redundancy will be essential in order to harness the potential of cytokines as therapeutics. Here, we discuss the biophysical (ligand-receptor geometry and affinity) and cellular (receptor trafficking and intracellular abundance of signaling molecules) parameters that contribute to the specificity of cytokine bioactivities. Whereas the role of extracellular ternary complex geometry in cytokine-induced signaling is still not completely elucidated, cytokine-receptor affinity is known to impact signaling through modulation of the stability and kinetics of ternary complex formation. Receptor trafficking also plays an important and likely underappreciated role in the diversification of cytokine bioactivities but it has been challenging to experimentally probe trafficking effects. We also review recent efforts to quantify levels of intracellular signaling components, as second messenger abundance can affect cytokine-induced bioactivities both quantitatively and qualitatively. We conclude by discussing the application of protein engineering to develop therapeutically relevant cytokines with reduced pleiotropy and redirected biological functionalities.
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Affiliation(s)
- Ignacio Moraga
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, California, USA; Program in Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Jamie Spangler
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, California, USA; Program in Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Juan L Mendoza
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, California, USA; Program in Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - K Christopher Garcia
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, California, USA; Program in Immunology, Stanford University School of Medicine, Stanford, California, USA.
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27
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Progress in detecting cell-surface protein receptors: the erythropoietin receptor example. Ann Hematol 2013; 93:181-92. [PMID: 24337485 PMCID: PMC3890056 DOI: 10.1007/s00277-013-1947-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/02/2013] [Indexed: 12/18/2022]
Abstract
Testing for the presence of specific cell-surface receptors (such as EGFR or HER2) on tumor cells is an integral part of cancer care in terms of treatment decisions and prognosis. Understanding the strengths and limitations of these tests is important because inaccurate results may occur if procedures designed to prevent false-negative or false-positive outcomes are not employed. This review discusses tests commonly used to identify and characterize cell-surface receptors, such as the erythropoietin receptor (EpoR). First, a summary is provided on the biology of the Epo/EpoR system, describing how EpoR is expressed on erythrocytic progenitors and precursors in the bone marrow where it mediates red blood cell production in response to Epo. Second, studies are described that investigated whether erythropoiesis-stimulating agents could stimulate tumor progression in cancer patients and whether EpoR is expressed and functional on tumor cells or on endothelial cells. The methods used in these studies included immunohistochemistry, Northern blotting, Western blotting, and binding assays. This review summarizes the strengths and limitations of these methods. Critically analyzing data from tests for cell-surface receptors such as EpoR requires understanding the techniques utilized and demonstrating that results are consistent with current knowledge about receptor biology.
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28
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Abstract
Recombinant human erythropoietin (rHuEPO), such as the approved agents epoetin alfa and epoetin beta, has been used successfully for over 20 years to treat anemia in millions of patients. However, due to the relatively short half-life of the molecule (approximately 8 hours), frequent dosing may be required to achieve required hemoglobin levels. Therefore, a need was identified in some anemic patient populations for erythropoiesis stimulating agents with longer half-lives that required less frequent dosing. This need led to the development of second generation molecules which are modified versions of rHuEPO with improved pharma-cokinetic and pharmacodynamic properties such as darbepoetin alfa, a hyperglycosylated analog of rHuEPO, and pegzyrepoetin, a pegylated rHuEPO. Third generation molecules, such as peginesatide, which are peptide mimetics that have no sequence homology to rHuEPO have also recently been developed. The various molecular, pharmacokinetic, and pharmacodynamic properties of these and other erythropoiesis stimulating agents will be discussed in this review.
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29
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Schmitz KR, Bagchi A, Roovers RC, van Bergen en Henegouwen PMP, Ferguson KM. Structural evaluation of EGFR inhibition mechanisms for nanobodies/VHH domains. Structure 2013; 21:1214-24. [PMID: 23791944 PMCID: PMC3733345 DOI: 10.1016/j.str.2013.05.008] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 05/04/2013] [Accepted: 05/14/2013] [Indexed: 01/07/2023]
Abstract
The epidermal growth factor receptor (EGFR) is implicated in human cancers and is the target of several classes of therapeutic agents, including antibody-based drugs. Here, we describe X-ray crystal structures of the extracellular region of EGFR in complex with three inhibitory nanobodies, the variable domains of heavy chain only antibodies (VHH). VHH domains, the smallest natural antigen-binding modules, are readily engineered for diagnostic and therapeutic applications. All three VHH domains prevent ligand-induced EGFR activation, but use two distinct mechanisms. 7D12 sterically blocks ligand binding to EGFR in a manner similar to that of cetuximab. EgA1 and 9G8 bind an epitope near the EGFR domain II/III junction, preventing receptor conformational changes required for high-affinity ligand binding and dimerization. This epitope is accessible to the convex VHH paratope but inaccessible to the flatter paratope of monoclonal antibodies. Appreciating the modes of binding and inhibition of these VHH domains will aid in developing them for tumor imaging and/or cancer therapy.
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Affiliation(s)
- Karl R. Schmitz
- Department of Physiology and Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, U.S.A
| | - Atrish Bagchi
- Department of Physiology and Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, U.S.A
| | - Rob C. Roovers
- Division of Cell Biology, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | | | - Kathryn M. Ferguson
- Department of Physiology and Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104, U.S.A
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30
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Liu Y, Schön A, Freire E. Optimization of CD4/gp120 inhibitors by thermodynamic-guided alanine-scanning mutagenesis. Chem Biol Drug Des 2013; 81:72-8. [PMID: 23066870 DOI: 10.1111/cbdd.12075] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
As protein/protein interactions usually trigger signalling processes, inhibitors of those interactions must preclude protein binding without eliciting the signalling process themselves. To accomplish those goals, small molecules need to target those protein residues that contribute the most to binding (binding hotspots) without disturbing those residues that initiate signalling processes (allosteric hotspots). The availability of a blueprint identifying binding and allosteric hotspots will significantly aid inhibitor design and optimization. In this study, we show that in some situations the blueprint can be constructed by combining the standard technique of alanine-scanning mutagenesis with isothermal titration calorimetry (ITC). We demonstrate the approach by developing the combined binding and allosteric hotspots blueprint for CD4/gp120, the initial interaction leading to HIV-1 cell infection. A major finding of these studies is that not all binding hotspots are allosteric hotspots opening the possibility for the rational design of inhibitors and antagonist or agonist modulators.
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Affiliation(s)
- Yingyun Liu
- Department of Biology, The Johns Hopkins University, 3400 North Charles, Baltimore, MD 21218, USA
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31
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Vascular growth factors in neuropsychiatry. Cell Mol Life Sci 2013; 70:1739-52. [PMID: 23475069 DOI: 10.1007/s00018-013-1281-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 01/28/2013] [Accepted: 01/28/2013] [Indexed: 01/03/2023]
Abstract
Recent advances in understanding the cellular and molecular basis of psychiatric illnesses have shed light on the important role played by trophic factors in modulating functional parameters associated with disease causality and drug action. Disease mechanisms are now thought to involve multiple cell types, including neurons and endothelial cells. These functionally distinct but interactively coupled cell types engage in cellular cross talk via shared and common signaling molecules. Dysregulation in their cellular signaling pathways influences brain function and alters behavioral performance. Multifunctional trophic factors such as VEGF and EPO that possess both neurotrophic and angiogenic actions are of particular interest due to their ability to rescue structural and plasticity deficits in neurons and vasculature. Obtaining insight into the behavioral, cellular and molecular actions of multi-functional trophic factors has the potential to open new and transformative therapeutic approaches.
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Atanasova M, Whitty A. Understanding cytokine and growth factor receptor activation mechanisms. Crit Rev Biochem Mol Biol 2012; 47:502-30. [PMID: 23046381 DOI: 10.3109/10409238.2012.729561] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Our understanding of the detailed mechanism of action of cytokine and growth factor receptors - and particularly our quantitative understanding of the link between structure, mechanism and function - lags significantly behind our knowledge of comparable functional protein classes such as enzymes, G protein-coupled receptors, and ion channels. In particular, it remains controversial whether such receptors are activated by a mechanism of ligand-induced oligomerization, versus a mechanism in which the ligand binds to a pre-associated receptor dimer or oligomer that becomes activated through subsequent conformational rearrangement. A major limitation to progress has been the relative paucity of methods for performing quantitative mechanistic experiments on unmodified receptors expressed at endogenous levels on live cells. In this article, we review the current state of knowledge on the activation mechanisms of cytokine and growth factor receptors, critically evaluate the evidence for and against the different proposed mechanisms, and highlight other key questions that remain unanswered. New approaches and techniques have led to rapid recent progress in this area, and the field is poised for major advances in the coming years which promise to revolutionize our understanding of this large and biologically and medically important class of receptors.
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Affiliation(s)
- Mariya Atanasova
- Department of Chemistry, Boston University, Boston, MA 02215, USA
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Abstract
Erythropoietin (Epo) is an essential hormone that binds and activates the Epo receptor (EpoR) resident on the surface of erythroid progenitor cells, thereby promoting erythropoiesis. Recombinant human erythropoietin has been used successfully for over 20 years to treat anemia in millions of patients. In addition to erythropoiesis, Epo has also been reported to have other effects, such as tissue protection and promotion of tumor cell growth or survival. This became of significant concern in 2003, when some clinical trials in cancer patients reported increased tumor progression and worse survival outcomes in patients treated with erythropoiesis-stimulating agents (ESAs). One of the potential mechanisms proffered to explain the observed safety issues was that functional EpoR was expressed in tumors and/or endothelial cells, and that ESAs directly stimulated tumor growth and/or antagonized tumor ablative therapies. Since then, numerous groups have performed further research evaluating this potential mechanism with conflicting data and conclusions. Here, we review the biology of endogenous Epo and EpoR expression and function in erythropoiesis, and evaluate the evidence pertaining to the expression of EpoR on normal nonhematopoietic and tumor cells.
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Mytych DT, Barger TE, King C, Grauer S, Haldankar R, Hsu E, Wu MM, Shiwalkar M, Sanchez S, Kuck A, Civoli F, Sun J, Swanson SJ. Development and characterization of a human antibody reference panel against erythropoietin suitable for the standardization of ESA immunogenicity testing. J Immunol Methods 2012; 382:129-41. [PMID: 22634015 DOI: 10.1016/j.jim.2012.05.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 05/17/2012] [Accepted: 05/18/2012] [Indexed: 01/16/2023]
Abstract
Recombinant human erythropoietin (EPO) has been used therapeutically for more than two decades in the treatment of anemia. Although EPO is generally well tolerated, in rare cases, patients have developed anti-EPO antibodies that can negatively impact safety and efficacy. Therefore, the detection of antibodies against EPO is a regulatory requirement during clinical development and post-approval. Although it is a rare phenomenon, antibody-mediated pure red cell aplasia (PRCA) is a serious complication than can result from antibodies that develop and neutralize EPO as well as endogenous erythropoietin. Currently, there are no universally accepted analytical methods to detect the full repertoire of binding and neutralizing anti-EPO antibodies. A number of different methods that differ in terms of antibodies detected and assay sensitivities are used by different manufacturers. There is also a lack of antibody reference reagents, and therefore no consistent basis for detecting and measuring anti-EPO antibodies. Reference reagents, with established ranges, are essential to monitor the safety and efficacy of all erythropoiesis-stimulating agents (ESAs) structurally related to human erythropoietin. This is the first report of the development and characterization of a panel of fully human antibodies against EPO suitable as reference reagents. The characteristics of antibodies within the panel were selected based on the prevalence of non-neutralizing IgG and IgM antibodies in non-PRCA patients and neutralizing IgG antibodies, including IgG1 and IgG4, in antibody-mediated PRCA subjects. The reference panel includes antibodies of high- and low-affinity with binding specificity to neutralizing and non-neutralizing erythropoietin epitopes. The subclass of human antibodies in this reference panel includes an IgG1, IgG2, and IgG4, as well as an IgM isotype. This antibody panel could help select appropriate immunogenicity assays, guide validation, and monitor assay performance. Further, this human anti-ESA antibody panel may help set the limits of each assay platform in terms of the full repertoire of the anti-ESA antibodies, and may facilitate standardization of ESA immunogenicity reporting across assay platforms.
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Affiliation(s)
- Daniel T Mytych
- Department of Clinical Immunology, Amgen, Thousand Oaks, CA 91320, USA.
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Debeljak N, Sytkowski AJ. Erythropoietin and erythropoiesis stimulating agents. Drug Test Anal 2012; 4:805-12. [PMID: 22508651 DOI: 10.1002/dta.1341] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/15/2012] [Accepted: 02/19/2012] [Indexed: 11/08/2022]
Abstract
Erythropoietin (EPO) is the main hormonal regulator of red blood cell production. Recombinant EPO has become the leading drug for treatment of anaemia from a variety of causes; however, it is sometimes misused in sport with the aim of improving performance and endurance. This paper presents an introductory overview of EPO, its receptor, and a variety of recombinant human EPOs/erythropoiesis stimulating agents (ESAs) available on the market (e.g. epoetins and their long acting analogs--darbepoetin alfa and continuous erythropoiesis receptor activator). Recent efforts to improve on EPO's pharmaceutical properties and to develop novel replacement products are also presented. In most cases, these efforts have emphasized a reduction in frequency of injections or complete elimination of intravenous or subcutaneous injections of the hormone (biosimilars, EPO mimetic peptides, fusion proteins, endogenous EPO gene activators and gene doping). Isoelectric focusing (IEF) combined with double immunoblotting can detect the subtle differences in glycosylation/sialylation, enabling differentiation among endogenous and recombinant EPO analogues. This method, using the highly sensitive anti-EPO monoclonal antibody AE7A5, has been accepted internationally as one of the methods for detecting misuse of ESAs in sport.
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Affiliation(s)
- Nataša Debeljak
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Slovenia
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Watowich SS. The erythropoietin receptor: molecular structure and hematopoietic signaling pathways. J Investig Med 2012; 59:1067-72. [PMID: 21307776 DOI: 10.2310/jim.0b013e31820fb28c] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The process of erythropoiesis in the fetal liver and adult bone marrow is regulated by the hormone erythropoietin (Epo), which is produced in the kidney at low levels under homeostatic conditions. Defects in Epo production result in severe anemia; use of recombinant hormone has improved the lives of patients with renal failure or anemia because of bone marrow suppression. Deletion of the Epo gene in mice leads to embryonic lethality at days 13 to 15, coincident with the establishment of definitive (adult-type) erythropoiesis and underscoring the absolute necessity of Epo function in vivo. Epo has proven to be a successful pharmaceutical agent, one of the early triumphs of recombinant protein technology. Because of its clinical importance, a great deal of attention has focused on the molecular mechanisms of Epo-regulated erythropoiesis. This review highlights the basic concepts of Epo signal transduction within the hematopoietic system, the major site of Epo action in vivo.
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Affiliation(s)
- Stephanie S Watowich
- Department of Immunology and Center for Inflammation and Cancer, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
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Erythropoietin mimetic compound AGEM400(HES) binds to the same receptor as erythropoietin but displays a different spectrum of activities. Cytokine 2012; 57:226-37. [DOI: 10.1016/j.cyto.2011.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 09/03/2011] [Accepted: 11/07/2011] [Indexed: 12/22/2022]
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Thermodynamics-based drug design: strategies for inhibiting protein-protein interactions. Future Med Chem 2012; 3:1129-37. [PMID: 21806377 DOI: 10.4155/fmc.11.81] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The inhibition of protein-protein interactions and their ensuing signaling processes play an increasingly important role in modern medicine. Small molecular-weight inhibitors that can be administered orally are the preferred approach but efficient strategies for developing them are not yet generally available. Due to the large size difference between the protein-protein interface and the small molecule, inhibitor interactions are expected to extend to only a small region of the interface. If this is the case, classical competitive inhibition may be hard to achieve. In addition, competitive inhibition wastes binding energy that can be effectively used to inhibit signaling. The best and most energy-efficient approach would be the development of small molecules that bind at the protein-protein interface and inhibit the signaling process without displacing the protein ligand. This approach seems feasible knowing that the binding energy is not evenly distributed within the binding interface but concentrated in discrete hotspots, and that the initiation of signaling may not overlap with those hotspots. We outline a general protein-protein inhibition model that extends from competitive to noncompetitive scenarios and apply it to the development of HIV-1 gp120-CD4 inhibitors. This rigorous model can be easily applied to the analysis of protein-protein inhibition data and used as a tool in the optimization of inhibitor molecules.
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Abstract
We report here an unliganded receptor structure in the common gamma-chain (γ(c)) family of receptors and cytokines. The crystal structure of the unliganded form of the interleukin-7 alpha receptor (IL-7Rα) extracellular domain (ECD) at 2.15 Å resolution reveals a homodimer forming an "X" geometry looking down onto the cell surface with the C termini of the two chains separated by 110 Å and the dimer interface comprising residues critical for IL-7 binding. Further biophysical studies indicate a weak association of the IL-7Rα ECDs but a stronger association between the γ(c)/IL-7Rα ECDs, similar to previous studies of the full-length receptors on CD4(+) T cells. Based on these and previous results, we propose a molecular mechanism detailing the progression from the inactive IL-7Rα homodimer and IL-7Rα-γ(c) heterodimer to the active IL-7-IL-7Rα-γ(c) ternary complex whereby the two receptors undergo at least a 90° rotation away from the cell surface, moving the C termini of IL-7Rα and γ(c) from a distance of 110 Å to less than 30 Å at the cell surface. This molecular mechanism can be used to explain recently discovered IL-7- and γ(c)-independent gain-of-function mutations in IL-7Rα from B- and T-cell acute lymphoblastic leukemia patients. The mechanism may also be applicable to other γ(c) receptors that form inactive homodimers and heterodimers independent of their cytokines.
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40
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Biener E, Charlier M, Ramanujan VK, Daniel N, Eisenberg A, Bjørbaek C, Herman B, Gertler A, Djiane J. Quantitative FRET imaging of leptin receptor oligomerization kinetics in single cells. Biol Cell 2012; 97:905-19. [PMID: 15771593 DOI: 10.1042/bc20040511] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION Leptin, an adipocyte-secreted hormone, signals through activation of its membrane-embedded receptor (LEPR). To study the leptin-induced events occurring in short (LEPRa) and long (LEPRb) LEPRs in the cell membrane, by FRET (fluorescence resonance energy transfer) methodology, the respective receptors, tagged at their C-terminal with CFP (cyan fluorescent protein) or YFP (yellow fluorescent protein), were prepared. RESULTS The constructs encoding mLEPRa (mouse LEPRa)-YFP and mLEPRa-CFP, mLEPRb-YFP and mLEPRb-CFP were tested for biological activity in transiently transfected CHO cells (Chinese-hamster ovary cells) and HEK-293T cells (human embryonic kidney 293 T cells) for activation of STAT3 (signal transduction and activators of transcription 3)-mediated LUC (luciferase) activity and binding of radiolabelled leptin. All four constructs were biologically active and were as potent as their untagged counterparts. The localization pattern of the fused protein appeared to be confined almost entirely to the cell membrane. The leptin-dependent interaction between various types of receptors in fixed cells were studied by measuring FRET, using fluorescence lifetime imaging microscopy and acceptor photobleaching methods. CONCLUSIONS Both methods yielded similar results, indicating that (1) leptin receptors expressed in the cell membrane exist mostly as preformed LEPRa/LEPRa or LEPRb/LEPRb homo-oligomers but not as LEPRb/LEPRa hetero-oligomers; (2) the appearance of transient leptin-induced FRET in cells transfected with LEPRb/LEPRb reflects both a conformational change that leads to closer interaction in the cytosolic part and a higher FRET signal, as well as de novo homo-oligomerization; (3) in LEPRa/LEPRa, exposure to leptin does not lead to any increase in FRET signalling as the proximity of CFP and YFP fluorophores in space already gives maximal FRET efficiency of the preoligomerized receptors.
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Affiliation(s)
- Eva Biener
- The Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
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The detection and quantitation of protein oligomerization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 747:19-41. [PMID: 22949109 DOI: 10.1007/978-1-4614-3229-6_2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
There are many different techniques available to biologists and biochemists that can be used to detect and characterize the self-association of proteins. Each technique has strengths and weaknesses and it is often useful to combine several approaches to maximize the former and minimize the latter. Here we review a range of methodologies that identify protein self-association and/or allow the stoichiometry and affinity of the interaction to be determined, placing an emphasis on what type of information can be obtained and outlining the advantages and disadvantages involved. In general, in vitro biophysical techniques, such as size exclusion chromatography, analytical ultracentrifugation, scattering techniques, NMR spectroscopy, isothermal titration calorimetry, fluorescence anisotropy and mass spectrometry, provide information on stoichiometry and/or binding affinities. Other approaches such as cross-linking, fluorescence methods (e.g., fluorescence correlation spectroscopy, FCS; Förster resonance energy transfer, FRET; fluorescence recovery after photobleaching, FRAP; and proximity imaging, PRIM) and complementation approaches (e.g., yeast two hybrid assays and bimolecular fluorescence complementation, BiFC) can be used to detect protein self-association in a cellular context.
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Pang X, Qin S, Zhou HX. Rationalizing 5000-fold differences in receptor-binding rate constants of four cytokines. Biophys J 2011; 101:1175-83. [PMID: 21889455 DOI: 10.1016/j.bpj.2011.06.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/06/2011] [Accepted: 06/08/2011] [Indexed: 11/30/2022] Open
Abstract
The four cytokines erythropoietin (EPO), interleukin-4 (IL4), human growth hormone (hGH), and prolactin (PRL) all form four-helix bundles and bind to type I cytokine receptors. However, their receptor-binding rate constants span a 5000-fold range. Here, we quantitatively rationalize these vast differences in rate constants by our transient-complex theory for protein-protein association. In the transient complex, the two proteins have near-native separation and relative orientation, but have yet to form the short-range specific interactions of the native complex. The theory predicts the association rate constant as k(a)=k(a0)exp(-ΔG(el)(∗)/k(B)T) where k(a0) is the basal rate constant for reaching the transient complex by random diffusion, and the Boltzmann factor captures the rate enhancement due to electrostatic attraction. We found that the vast differences in receptor-binding rate constants of the four cytokines arise mostly from the differences in charge complementarity among the four cytokine-receptor complexes. The basal rate constants (k(a0)) of EPO, IL4, hGH, and PRL were similar (5.2 × 10(5) M(-1)s(-1), 2.4 × 10(5) M(-1)s(-1), 1.7 × 10(5) M(-1)s(-1), and 1.7 × 10(5) M(-1)s(-1), respectively). However, the average electrostatic free energies (ΔG(e1)(∗)) were very different (-4.2 kcal/mol, -2.4 kcal/mol, -0.1 kcal/mol, and -0.5 kcal/mol, respectively, at ionic strength=160 mM). The receptor-binding rate constants predicted without adjusting any parameters, 6.2 × 10(8) M(-1)s(-1), 1.3 × 10(7) M(-1)s(-1), 2.0 × 10(5) M(-1)s(-1), and 7.6 × 10(4) M(-1)s(-1), respectively, for EPO, IL4, hGH, and PRL agree well with experimental results. We uncover that these diverse rate constants are anticorrelated with the circulation concentrations of the cytokines, with the resulting cytokine-receptor binding rates very close to the limits set by the half-lives of the receptors, suggesting that these binding rates are functionally relevant and perhaps evolutionarily tuned. Our calculations also reproduced well-observed effects of mutations and ionic strength on the rate constants and produced a set of mutations on the complex of hGH with its receptor that putatively enhances the rate constant by nearly 100-fold through increasing charge complementarity. To quantify charge complementarity, we propose a simple index based on the charge distribution within the binding interface, which shows good correlation with ΔG(e1)(∗). Together these results suggest that protein charges can be manipulated to tune k(a) and control biological function.
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Affiliation(s)
- Xiaodong Pang
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
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Li J, Xu H, Gao Q, Wen Y. Effect of erythropoiesis-stimulating agents in acute ST-segment elevation myocardial infarction: a systematic review. Eur J Clin Pharmacol 2011; 68:469-77. [DOI: 10.1007/s00228-011-1160-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
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An extra high dose of erythropoietin fails to support the proliferation of erythropoietin dependent cell lines. Cytotechnology 2011; 63:101-9. [PMID: 21380566 DOI: 10.1007/s10616-011-9345-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2007] [Accepted: 10/05/2007] [Indexed: 10/18/2022] Open
Abstract
Erythropoietin is responsible for the red blood cell formation by stimulating the proliferation and the differentiation of erythroid precursor cells. Erythropoietin triggers the conformational change in its receptor thereby induces the phosphorylation of JAK2. In this study, we show that an extra high dose of erythropoietin, however, fails to activate the erythropoietin receptor, to stimulate the phosphorylation of JAK2 and to support the cell proliferation of Ep-FDC-P2 cell. Moreover, high dose of EPO also inhibited the proliferation of various erythropoietin-dependent cell lines, suggesting that excess amount of EPO could not trigger the conformational change of the receptor. In the presence of an extra high dose of erythropoietin as well as in the absence of erythropoietin, the cells caused the DNA fragmentation, a typical symptom of apoptosis. The impairment of cell growth and the DNA fragmentation at the extremely high concentration of EPO was rescued by the addition of erythropoietin antibody or soluble form of erythropoietin receptor by titrating the excess erythropoietin. These results suggest that two erythropoietin binding sites on erythropoietin receptor dimer should be occupied by a single erythropoietin molecule for the proper conformational change of the receptor and the signal transduction of erythropoietin, instead, when two erythropoietin binding sites on the receptor are shared by two erythropoietin molecules, it fails to evoke the conformational change of erythropoietin receptor adequate for signal transduction.
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Abstract
This is a Minireview covering landmarks or milestones in the development of erythropoietin (EPO). Thirty-nine landmark advances have been identified, which cover the period 1863-2003. Several reports are included that directly support these original landmark advances. This Minireview also updates some of the advances in EPO research since my last Minireview update on EPO published in this journal in 2003. The areas of EPO research updated are: sites of production; purification, assay and standardization; regulation; action; use in anemias; extraerythropoietic actions; adverse effects; and blood doping. The new reports on the use of EPO in the therapy of myocardial infarction; stroke and other neurological diseases; diabetic retinopathy and other retinal diseases are also covered.
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Affiliation(s)
- James W Fisher
- Department of Pharmacology, Tulane University, School of Medicine, New Orleans, LA 70112, USA.
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46
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47
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Abstract
PURPOSE To compare the quality of therapeutic erythropoietin (EPO) products, including two biosimilars, with respect to content, aggregation, isoform profile and potency. METHODS Two original products, Eprex (epoetin alpha) and Dynepo (epoetin delta), and two biosimilar products, Binocrit (epoetin alpha) and Retacrit (epoetin zeta), were compared using (1) high performance size exclusion chromatography, (2) ELISA, (3) SDS-PAGE, (4) capillary zone electrophoresis and (5) in-vivo potency. RESULTS Tested EPO products differed in content, isoform composition, and potency. CONCLUSION Of the tested products, the biosimilars have the same or even better quality as the originals. Especially, the potency of originals may significantly differ from the value on the label.
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Hansen MJK, Olsen JG, Bernichtein S, O'Shea C, Sigurskjold BW, Goffin V, Kragelund BB. Development of prolactin receptor antagonists with reduced pH-dependence of receptor binding. J Mol Recognit 2010; 24:533-47. [PMID: 20842635 DOI: 10.1002/jmr.1064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 05/26/2010] [Accepted: 05/26/2010] [Indexed: 01/03/2023]
Abstract
The cytokine hormone prolactin has a vast number of diverse functions. Unfortunately, it also exhibits tumor growth promoting properties, which makes the development of prolactin receptor antagonists a priority. Prolactin binds to its cognate receptor with much lower affinity at low pH than at physiological pH and since the extracellular environment around solid tumors often is acidic, it is desirable to develop antagonists that have improved binding affinity at low pH. The pK(a) value of a histidine side chain is ∼6.8 making histidine residues obvious candidates for examination. From evaluation of known molecular structures of human prolactin, of the prolactin receptor and of different complexes of the two, three histidine residues in the hormone-receptor binding site 1 were selected for mutational studies. We analyzed 10 variants by circular dichroism spectroscopy, affinity and thermodynamic characterization of receptor binding by isothermal titration calorimetry combined with in vitro bioactivity in living cells. Histidine residue 27 was recognized as a central hot spot for pH sensitivity and conservative substitutions at this site resulted in strong receptor binding at low pH. Pure antagonists were developed earlier and the histidine mutations were introduced within such background. The antagonistic properties were maintained and the high affinity at low pH conserved. The implications of these findings may open new areas of research in the field of prolactin cancer biology.
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Affiliation(s)
- Mathilde J Kaas Hansen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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Radhakrishnan ML, Tidor B. Cellular level models as tools for cytokine design. Biotechnol Prog 2010; 26:919-37. [PMID: 20568274 DOI: 10.1002/btpr.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cytokines and growth factors are critical regulators that connect intracellular and extracellular environments through binding to specific cell-surface receptors. They regulate a wide variety of immunological, growth, and inflammatory response processes. The overall signal initiated by a population of cytokine molecules over long time periods is controlled by the subtle interplay of binding, signaling, and trafficking kinetics. Building on the work of others, we abstract a simple kinetic model that captures relevant features from cytokine systems as well as related growth factor systems. We explore a large range of potential biochemical behaviors, through systematic examination of the model's parameter space. Different rates for the same reaction topology lead to a dramatic range of biochemical network properties and outcomes. Evolution might productively explore varied and different portions of parameter space to create beneficial behaviors, and effective human therapeutic intervention might be achieved through altering network kinetic properties. Quantitative analysis of the results reveals the basis for tensions among a number of different network characteristics. For example, strong binding of cytokine to receptor can increase short-term receptor activation and signal initiation but decrease long-term signaling due to internalization and degradation. Further analysis reveals the role of specific biochemical processes in modulating such tensions. For instance, the kinetics of cytokine binding and receptor activation modulate whether ligand-receptor dissociation can generally occur before signal initiation or receptor internalization. Beyond analysis, the same models and model behaviors provide an important basis for the design of more potent cytokine therapeutics by providing insight into how binding kinetics affect ligand potency.
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Affiliation(s)
- Mala L Radhakrishnan
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139
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50
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Ogawa H, Qiu Y, Philo JS, Arakawa T, Ogata CM, Misono KS. Reversibly bound chloride in the atrial natriuretic peptide receptor hormone-binding domain: possible allosteric regulation and a conserved structural motif for the chloride-binding site. Protein Sci 2010; 19:544-57. [PMID: 20066666 DOI: 10.1002/pro.332] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The binding of atrial natriuretic peptide (ANP) to its receptor requires chloride, and it is chloride concentration dependent. The extracellular domain (ECD) of the ANP receptor (ANPR) contains a chloride near the ANP-binding site, suggesting a possible regulatory role. The bound chloride, however, is completely buried in the polypeptide fold, and its functional role has remained unclear. Here, we have confirmed that chloride is necessary for ANP binding to the recombinant ECD or the full-length ANPR expressed in CHO cells. ECD without chloride (ECD(-)) did not bind ANP. Its binding activity was fully restored by bromide or chloride addition. A new X-ray structure of the bromide-bound ECD is essentially identical to that of the chloride-bound ECD. Furthermore, bromide atoms are localized at the same positions as chloride atoms both in the apo and in the ANP-bound structures, indicating exchangeable and reversible halide binding. Far-UV CD and thermal unfolding data show that ECD(-) largely retains the native structure. Sedimentation equilibrium in the absence of chloride shows that ECD(-) forms a strongly associated dimer, possibly preventing the structural rearrangement of the two monomers that is necessary for ANP binding. The primary and tertiary structures of the chloride-binding site in ANPR are highly conserved among receptor-guanylate cyclases and metabotropic glutamate receptors. The chloride-dependent ANP binding, reversible chloride binding, and the highly conserved chloride-binding site motif suggest a regulatory role for the receptor bound chloride. Chloride-dependent regulation of ANPR may operate in the kidney, modulating ANP-induced natriuresis.
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Affiliation(s)
- Haruo Ogawa
- Department of Biochemistry, University of Nevada School of Medicine, Reno, Nevada 89557, USA
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