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Khullar D, Muchhala SS, T A. Advancing Anemia Management in Chronic Kidney Disease: Assessing the Superiority of Darbepoetin Alfa Over Erythropoietin Alpha. Cureus 2024; 16:e51613. [PMID: 38313992 PMCID: PMC10837100 DOI: 10.7759/cureus.51613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2024] [Indexed: 02/06/2024] Open
Abstract
Anemia is a prevalent and debilitating complication in patients with chronic kidney disease (CKD). It presents multifaceted challenges that impact patients' quality of life and overall well-being. The advent of darbepoetin alfa (DPO) as a therapeutic alternative to recombinant human erythropoietin alpha (EPO) has revolutionized the management of CKD-associated anemia. This review article presents a comprehensive comparative analysis highlighting the advantages of DPO over EPO in the effective management of anemia, in both predialysis and dialysis-dependent (DD) CKD patients. DPO's distinct pharmacokinetic advantages play a pivotal role in its efficacy and safety. With a significantly longer half-life and several-fold increased biological activity compared to EPO, DPO enables extended dosing intervals. Through an in-depth examination of diverse clinical trials, it becomes evident that DPO consistently demonstrates remarkable efficacy and safety in improving and maintaining hemoglobin (Hb) levels. Furthermore, its simplified dosage regimen, coupled with the convenience of less frequent administration, not only improves patient adherence but also translates to reduced healthcare costs and resource utilization. In conclusion, this review provides compelling evidence of the advantages of DPO over conventional recombinant human EPO for managing anemia in CKD patients, both in the predialysis and dialysis-dependent CKD patients. DPO's pharmacokinetic advantages, patient-centered advantages, enhanced compliance, and cost-effectiveness converge to establish DPO as a transformative therapeutic option. In both predialysis and dialysis settings, DPO's superior efficacy and patient-centric attributes collectively redefine the landscape of anemia management in CKD.
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Affiliation(s)
- Dinesh Khullar
- Nephrology and Renal Transplant Medicine, Max Super Specialty Hospital, New Delhi, IND
| | | | - Abhishek T
- Medical Affairs, Dr. Reddy's Laboratories, Hyderabad, IND
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2
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Pan W, Meshcheryakov VA, Li T, Wang Y, Ghosh G, Wang VYF. Structures of NF-κB p52 homodimer-DNA complexes rationalize binding mechanisms and transcription activation. eLife 2023; 12:e86258. [PMID: 36779700 PMCID: PMC9991059 DOI: 10.7554/elife.86258] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 02/07/2023] [Indexed: 02/14/2023] Open
Abstract
The mammalian NF-κB p52:p52 homodimer together with its cofactor Bcl3 activates transcription of κB sites with a central G/C base pair (bp), while it is inactive toward κB sites with a central A/T bp. To understand the molecular basis for this unique property of p52, we have determined the crystal structures of recombinant human p52 protein in complex with a P-selectin(PSel)-κB DNA (5'-GGGGTGACCCC-3') (central bp is underlined) and variants changing the central bp to A/T or swapping the flanking bp. The structures reveal a nearly two-fold widened minor groove in the central region of the DNA as compared to all other currently available NF-κB-DNA complex structures, which have a central A/T bp. Microsecond molecular dynamics (MD) simulations of free DNAs and p52 bound complexes reveal that free DNAs exhibit distinct preferred conformations, and p52:p52 homodimer induces the least amount of DNA conformational changes when bound to the more transcriptionally active natural G/C-centric PSel-κB, but adopts closed conformation when bound to the mutant A/T and swap DNAs due to their narrowed minor grooves. Our binding assays further demonstrate that the fast kinetics favored by entropy is correlated with higher transcriptional activity. Overall, our studies have revealed a novel conformation for κB DNA in complex with NF-κB and pinpoint the importance of binding kinetics, dictated by DNA conformational and dynamic states, in controlling transcriptional activation for NF-κB.
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Affiliation(s)
- Wenfei Pan
- Faculty of Health Sciences, University of MacauTaipaChina
| | | | - Tianjie Li
- Department of Physics, Chinese University of Hong KongShatinHong Kong
| | - Yi Wang
- Department of Physics, Chinese University of Hong KongShatinHong Kong
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California, San DiegoLa JollaUnited States
| | - Vivien Ya-Fan Wang
- Faculty of Health Sciences, University of MacauTaipaChina
- MoE Frontiers Science Center for Precision Oncology, University of MacauTaipaMacao
- Cancer Centre, Faculty of Health Sciences, University of MacauTaipaChina
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3
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Wu N, Widness JA, Yan X, Veng-Pedersen P, An G. A Full Target-Mediated Drug Disposition (TMDD) Model to Explain the Changes in Recombinant Human Erythropoietin (rhEpo) Pharmacokinetics in Patients with Different Bone Marrow Integrity Following Hematopoietic Transplantation. J Pharm Sci 2022; 111:2620-2629. [PMID: 35691608 PMCID: PMC9391296 DOI: 10.1016/j.xphs.2022.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/03/2022] [Accepted: 06/03/2022] [Indexed: 11/28/2022]
Abstract
Our aim was to build a mechanistic full target-mediated drug disposition (TMDD) model for rhEpo to better understand rhEpo disposition, Epo receptor (EpoR) synthesis, and degradation in hematopoietic transplant patients with four distinct bone marrow conditions. All PK data were analyzed simultaneously using the nonlinear mixed effect modeling approach with NONMEM. The final model was a two-compartmental full TMDD model, which adequately characterizes rhEpo PK in patients and provides insight into the dynamics of free EpoR, rhEpo-EpoR, and total EpoR. The model predicted association rate constant (kon), dissociation rate constant (koff), and internalization rate constant (kint) were 0.0276 pM-1h-1, 0.647 h-1, and 0.255h-1, respectively, which were supported by experimental data. Also, the EpoR degradation rate constant (kdeg) was estimated to be 0.461 h-1. EpoR production rate was estimated to be 37.5 pM/h for adults at pre-ablation baseline and 5.91 pM/h, and 4.19 pM/h in the early post-transplant post-engraftment, and late post-transplant full engraftment. Our model provides extensive information on the dynamics of free EpoR, total EpoR and rhEpo-EpoR, and proven to be more robust and can provide more physiologically relevant binding parameters than previous models.
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Affiliation(s)
- Nan Wu
- Division of Pharmaceutics and Translational Therapeutics, College of Pharmacy, University of Iowa, Iowa city, Iowa, USA
| | - John A Widness
- Department of Pediatrics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Xiaoyu Yan
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Peter Veng-Pedersen
- Division of Pharmaceutics and Translational Therapeutics, College of Pharmacy, University of Iowa, Iowa city, Iowa, USA
| | - Guohua An
- Division of Pharmaceutics and Translational Therapeutics, College of Pharmacy, University of Iowa, Iowa city, Iowa, USA.
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4
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Allenby MC, Okutsu N, Brailey K, Guasch J, Zhang Q, Panoskaltsis N, Mantalaris A. A spatiotemporal microenvironment model to improve design of a 3D bioreactor for red cell production. Tissue Eng Part A 2021; 28:38-53. [PMID: 34130508 DOI: 10.1089/ten.tea.2021.0028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cellular microenvironments provide stimuli including paracrine and autocrine growth factors and physico-chemical cues, which support efficient in vivo cell production unmatched by current in vitro biomanufacturing platforms. While three-dimensional (3D) culture systems aim to recapitulate niche architecture and function of the target tissue/organ, they are limited in accessing spatiotemporal information to evaluate and optimize in situ cell/tissue process development. Herein, a mathematical modelling framework is parameterized by single-cell phenotypic imaging and multiplexed biochemical assays to simulate the non-uniform tissue distribution of nutrients/metabolites and growth factors in cell niche environments. This model is applied to a bone marrow mimicry 3D perfusion bioreactor containing dense stromal and hematopoietic tissue with limited red blood cell (RBC) egress. The model characterized an imbalance between endogenous cytokine production and nutrient starvation within the microenvironmental niches, and recommended increased cell inoculum density and enhanced medium exchange, guiding the development of a miniaturized prototype bioreactor. The second-generation prototype improved the distribution of nutrients and growth factors and supported a 50-fold increase in RBC production efficiency. This image-informed bioprocess modelling framework leverages spatiotemporal niche information to enhance biochemical factor utilization and improve cell manufacturing in 3D systems.
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Affiliation(s)
- Mark Colin Allenby
- Queensland University of Technology, 1969, Institute of Health and Biomedical Innovation (IHBI), Kelvin Grove, Queensland, Australia.,Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Naoki Okutsu
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Kate Brailey
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Joana Guasch
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Qiming Zhang
- Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Nicki Panoskaltsis
- Emory University, 1371, Winship Cancer Institute, Department of Hematology & Medical Oncology, Atlanta, Georgia, United States.,Imperial College London, 4615, Department of Haematology, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Athanasios Mantalaris
- Georgia Institute of Technology, 1372, BME, Atlanta, Georgia, United States.,Imperial College London, 4615, Department of Chemical Engineering, London, London, United Kingdom of Great Britain and Northern Ireland;
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Lutz IC, Allegaert K, de Hoon JN, Marynissen H. Pharmacokinetics during therapeutic hypothermia for neonatal hypoxic ischaemic encephalopathy: a literature review. BMJ Paediatr Open 2020; 4:e000685. [PMID: 32577535 PMCID: PMC7299043 DOI: 10.1136/bmjpo-2020-000685] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Neonatal hypoxic ischaemic encephalopathy due to perinatal asphyxia, can result in severe neurodevelopmental disability or mortality. Hypothermia is at present the only proven neuroprotective intervention. During hypothermia, the neonate may need a variety of drugs with their specific pharmacokinetic profile. The aim of this paper is to determine the effect that hypothermia for neonates suffering from hypoxic ischaemic encephalopathy has on the pharmacokinetics and to what extent dosing regimens need adjustments. METHOD A systematic search was performed on PubMed, Embase and Cochrane Library of literature (2000-2020) using a combination of the following search terms: therapeutic hypothermia, neonate, hypoxic ischemic encephalopathy and pharmacokinetics. Titles and abstracts were screened, and inclusion/exclusion criteria were applied. Finally, relevant full texts were read, and secondary inclusion was applied on the identified articles. RESULTS A total of 380 articles were retrieved, and 34 articles included after application of inclusion/exclusion criteria and duplicate removal, two additional papers were included as suggested by the reviewers. Twelve out of 36 studies on 15 compounds demonstrated a significant decrease in clearance, be it that the extent differs between routes of elimination and compounds, most pronounced for renal elimination (phenobarbital no difference, midazolam metabolite -21%, lidocaine -24%; morphine -21% to -47%, gentamicin -25% to -35%, amikacin -40%) during hypothermia. The data as retrieved in literature were subsequent compared with the dosing regimen as stated in the Dutch paediatric formulary. CONCLUSION Depending on the drug-specific disposition characteristics, therapeutic hypothermia in neonates with hypoxic ischaemic encephalopathy affects pharmacokinetics.
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Affiliation(s)
| | - Karel Allegaert
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium
- Intensive Care and Pediatric Surgery, Erasmus MC Sophia, Rotterdam, The Netherlands
| | - Jan N de Hoon
- Department of Pharmaceutical and Pharmacological Sciences, Center for Clinical Pharmacology, KU Leuven, Leuven, Belgium
| | - Heleen Marynissen
- Department of Pharmaceutical and Pharmacological Sciences, Center for Clinical Pharmacology, KU Leuven, Leuven, Belgium
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Pan X, Stader F, Abduljalil K, Gill KL, Johnson TN, Gardner I, Jamei M. Development and Application of a Physiologically-Based Pharmacokinetic Model to Predict the Pharmacokinetics of Therapeutic Proteins from Full-term Neonates to Adolescents. AAPS JOURNAL 2020; 22:76. [DOI: 10.1208/s12248-020-00460-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/15/2020] [Indexed: 02/07/2023]
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7
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Chang TC, Chen BM, Lin WW, Yu PH, Chiu YW, Chen YT, Wu JY, Cheng TL, Hwang DY, Roffler S. Both IgM and IgG Antibodies Against Polyethylene Glycol Can Alter the Biological Activity of Methoxy Polyethylene Glycol-Epoetin Beta in Mice. Pharmaceutics 2019; 12:E15. [PMID: 31877813 PMCID: PMC7022322 DOI: 10.3390/pharmaceutics12010015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/18/2019] [Indexed: 02/06/2023] Open
Abstract
Pre-existing antibodies that bind polyethylene glycol are present in about 40% of healthy individuals. It is currently unknown if pre-existing anti-polyethylene glycol (PEG) antibodies can alter the bioactivity of pegylated drugs with a single long PEG chain, which represents the majority of newly developed pegylated medicines. Methoxy polyethylene glycol-epoetin beta (PEG-EPO) contains a single 30 kDa PEG chain and is used to treat patients suffering from anemia. We find that the pre-existing human anti-PEG IgM and IgG antibodies from normal donors can bind to PEG-EPO. The prevalence and concentrations of anti-PEG IgM and IgG antibodies were also higher in patients that responded poorly to PEG-EPO. Monoclonal anti-PEG IgM and IgG antibodies at concentrations found in normal donors blocked the biological activity of PEG-EPO to stimulate the production of new erythrocytes in mice and accelerated the clearance of 125I-PEG-EPO, resulting in PEG-EPO accumulation primarily in the liver and spleen. Accelerated clearance by the anti-PEG IgG antibody was mediated by the Fc portion of the antibody. Importantly, infusing higher doses of PEG-EPO could compensate for the inhibitory effects of anti-PEG antibodies, suggesting that pre-existing anti-PEG antibodies can be "dosed through." Our study indicates that the bioactivity and therapeutic activity of PEG-EPO may be reduced in patients with elevated levels of pre-existing anti-PEG antibodies. New pegylated medicines with a single long PEG chain may also be affected in patients with high levels of anti-PEG antibodies.
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Affiliation(s)
- Tien-Ching Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan; (T.-C.C.)
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei 11529, Taiwan
| | - Bing-Mae Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan; (T.-C.C.)
| | - Wen-Wei Lin
- Department of Laboratory Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Pei-Hua Yu
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
| | - Yi-Wen Chiu
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
| | - Yuan-Tsong Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan; (T.-C.C.)
| | - Jer-Yuarn Wu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan; (T.-C.C.)
- School of Chinese Medicine, China Medical University, Taichung 40447, Taiwan
| | - Tian-Lu Cheng
- Department of Biomedical Science and Environmental Biology, Center for Biomarkers and Biotech Drugs, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Daw-Yang Hwang
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
- National Institute of Cancer Research, National Health Research Institutes, Tainan 70456, Taiwan
| | - Steve Roffler
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan; (T.-C.C.)
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
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8
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Arterial oxygen content regulates plasma erythropoietin independent of arterial oxygen tension: a blinded crossover study. Kidney Int 2019; 95:173-177. [DOI: 10.1016/j.kint.2018.09.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 08/30/2018] [Accepted: 09/06/2018] [Indexed: 01/07/2023]
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9
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Deregulated iron metabolism in bone marrow from adenine-induced mouse model of chronic kidney disease. Int J Hematol 2018; 109:59-69. [DOI: 10.1007/s12185-018-2531-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 12/11/2022]
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10
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Shih HM, Wu CJ, Lin SL. Physiology and pathophysiology of renal erythropoietin-producing cells. J Formos Med Assoc 2018; 117:955-963. [PMID: 29655605 DOI: 10.1016/j.jfma.2018.03.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 02/05/2023] Open
Abstract
Anemia is a common complication and contributes to increased morbidity and mortality in chronic kidney disease (CKD) patients. Whereas there has been a significant improvement of understanding the underlying mechanism of erythropoiesis, the treatment of renal anemia is still restricted to erythropoietin (EPO)-stimulating agents. The purpose of this article is to review the physiology of erythropoiesis, functional role of EPO and underlying molecular and cellular basis that regulate EPO production. Regulation of EPO production is at mRNA level. When anemia or hypoxia occurs, transcriptional factor, hypoxia-inducible factor (HIF), binds to EPO 5' hypoxic response element and EPO gene transcription increases. The renal EPO is mainly produced by pericytes. In CKD, pericytes transdifferentiate to myofibroblasts, and subsequently the ability of EPO production decreases, leading to renal anemia. Recent experimental and clinical studies show the promising efficacy of prolyl hydroxylase inhibitors in renal anemia through increasing EPO production by stabilizing HIF. Recent advances on epigenetics create a new field to study EPO gene expression at chromatin level. We will discuss the role of demethylating agent on restoring EPO expression, providing a novel approach to the treatment of renal anemia.
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Affiliation(s)
- Hong-Mou Shih
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan; Division of Nephrology, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan
| | - Chih-Jen Wu
- Division of Nephrology, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medicine, Mackay Medical College, Taipei, Taiwan; Graduate Institute of Medical Sciences and Department of Pharmacology, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shuei-Liong Lin
- Graduate Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan; Renal Division, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; Department of Integrated Diagnostics &Therapeutics, National Taiwan University Hospital, Taipei, Taiwan; Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei, Taiwan.
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11
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Kallenberger SM, Unger AL, Legewie S, Lymperopoulos K, Klingmüller U, Eils R, Herten DP. Correlated receptor transport processes buffer single-cell heterogeneity. PLoS Comput Biol 2017; 13:e1005779. [PMID: 28945754 PMCID: PMC5659801 DOI: 10.1371/journal.pcbi.1005779] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 10/27/2017] [Accepted: 09/19/2017] [Indexed: 11/25/2022] Open
Abstract
Cells typically vary in their response to extracellular ligands. Receptor transport processes modulate ligand-receptor induced signal transduction and impact the variability in cellular responses. Here, we quantitatively characterized cellular variability in erythropoietin receptor (EpoR) trafficking at the single-cell level based on live-cell imaging and mathematical modeling. Using ensembles of single-cell mathematical models reduced parameter uncertainties and showed that rapid EpoR turnover, transport of internalized EpoR back to the plasma membrane, and degradation of Epo-EpoR complexes were essential for receptor trafficking. EpoR trafficking dynamics in adherent H838 lung cancer cells closely resembled the dynamics previously characterized by mathematical modeling in suspension cells, indicating that dynamic properties of the EpoR system are widely conserved. Receptor transport processes differed by one order of magnitude between individual cells. However, the concentration of activated Epo-EpoR complexes was less variable due to the correlated kinetics of opposing transport processes acting as a buffering system. Cell surface receptors translate extracellular ligand concentrations to intracellular responses. Receptor transport between the plasma membrane and other cellular compartments regulates the number of accessible receptors at the plasma membrane that determines the strength of downstream pathway activation at a given ligand concentration. In cell populations, pathway activation strength and cellular responses vary between cells. Understanding origins of cell-to-cell variability is highly relevant for cancer research, motivated by the problem of fractional killing by chemotherapies and development of resistance in subpopulations of tumor cells. The erythropoietin receptor (EpoR) is a characteristic example of a receptor system that strongly depends on receptor transport processes. It is involved in several cellular processes, such as differentiation or proliferation, regulates the renewal of erythrocytes, and is expressed in several tumors. To investigate the involvement of receptor transport processes in cell-to-cell variability, we quantitatively characterized trafficking of EpoR in individual cells by combining live-cell imaging with mathematical modeling. Thereby, we found that EpoR dynamics was strongly dependent on rapid receptor transport and turnover. Interestingly, although transport processes largely differed between individual cells, receptor concentrations in cellular compartments were robust to variability in trafficking processes due to the correlated kinetics of opposing transport processes.
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Affiliation(s)
- Stefan M. Kallenberger
- Department for Bioinformatics and Functional Genomics, Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Anne L. Unger
- Cellnetworks Cluster and Institute of Physical Chemistry, BioQuant, Heidelberg University, Heidelberg, Germany
| | | | - Konstantinos Lymperopoulos
- Cellnetworks Cluster and Institute of Physical Chemistry, BioQuant, Heidelberg University, Heidelberg, Germany
| | - Ursula Klingmüller
- Division Systems Biology of Signal Transduction, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
- * E-mail: (DPH); (RE); (UK)
| | - Roland Eils
- Department for Bioinformatics and Functional Genomics, Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
- * E-mail: (DPH); (RE); (UK)
| | - Dirk-Peter Herten
- Cellnetworks Cluster and Institute of Physical Chemistry, BioQuant, Heidelberg University, Heidelberg, Germany
- * E-mail: (DPH); (RE); (UK)
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12
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Kuhn V, Diederich L, Keller TCS, Kramer CM, Lückstädt W, Panknin C, Suvorava T, Isakson BE, Kelm M, Cortese-Krott MM. Red Blood Cell Function and Dysfunction: Redox Regulation, Nitric Oxide Metabolism, Anemia. Antioxid Redox Signal 2017; 26:718-742. [PMID: 27889956 PMCID: PMC5421513 DOI: 10.1089/ars.2016.6954] [Citation(s) in RCA: 230] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SIGNIFICANCE Recent clinical evidence identified anemia to be correlated with severe complications of cardiovascular disease (CVD) such as bleeding, thromboembolic events, stroke, hypertension, arrhythmias, and inflammation, particularly in elderly patients. The underlying mechanisms of these complications are largely unidentified. Recent Advances: Previously, red blood cells (RBCs) were considered exclusively as transporters of oxygen and nutrients to the tissues. More recent experimental evidence indicates that RBCs are important interorgan communication systems with additional functions, including participation in control of systemic nitric oxide metabolism, redox regulation, blood rheology, and viscosity. In this article, we aim to revise and discuss the potential impact of these noncanonical functions of RBCs and their dysfunction in the cardiovascular system and in anemia. CRITICAL ISSUES The mechanistic links between changes of RBC functional properties and cardiovascular complications related to anemia have not been untangled so far. FUTURE DIRECTIONS To allow a better understanding of the complications associated with anemia in CVD, basic and translational science studies should be focused on identifying the role of noncanonical functions of RBCs in the cardiovascular system and on defining intrinsic and/or systemic dysfunction of RBCs in anemia and its relationship to CVD both in animal models and clinical settings. Antioxid. Redox Signal. 26, 718-742.
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Affiliation(s)
- Viktoria Kuhn
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - Lukas Diederich
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - T C Stevenson Keller
- 2 Department of Molecular Physiology and Biological Physics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Christian M Kramer
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - Wiebke Lückstädt
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - Christina Panknin
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - Tatsiana Suvorava
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - Brant E Isakson
- 2 Department of Molecular Physiology and Biological Physics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Malte Kelm
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
| | - Miriam M Cortese-Krott
- 1 Cardiovascular Research Laboratory, Division of Cardiology, Pneumology, and Vascular Medicine, Medical Faculty, Heinrich Heine University of Düsseldorf , Düsseldorf, Germany
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13
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KAUSAR H, GULL S, AHMAD W, AWAN SJ, SARWAR MT, IJAZ B, ANSAR M, ASAD S, HASSAN S. Role of alternative phosphorylation and O-glycosylation of erythropoietinreceptor in modulating its function: an in silico study. Turk J Biol 2017. [DOI: 10.3906/biy-1704-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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14
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Chen PH, Yao H, Huang LJS. Cytokine Receptor Endocytosis: New Kinase Activity-Dependent and -Independent Roles of PI3K. Front Endocrinol (Lausanne) 2017; 8:78. [PMID: 28507533 PMCID: PMC5410625 DOI: 10.3389/fendo.2017.00078] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/30/2017] [Indexed: 12/14/2022] Open
Abstract
Type I and II cytokine receptors are cell surface sensors that bind cytokines in the extracellular environment and initiate intracellular signaling to control processes such as hematopoiesis, immune function, and cellular growth and development. One key mechanism that regulates signaling from cytokine receptors is through receptor endocytosis. In this mini-review, we describe recent advances in endocytic regulations of cytokine receptors, focusing on new paradigms by which PI3K controls receptor endocytosis through both kinase activity-dependent and -independent mechanisms. These advances underscore the notion that the p85 regulatory subunit of PI3K has functions beyond regulating PI3K kinase activity, and that PI3K plays both positive and negative roles in receptor signaling. On the one hand, the PI3K/Akt pathway controls various aspects downstream of cytokine receptors. On the other hand, it stimulates receptor endocytosis and downregulation, thus contributing to signaling attenuation.
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Affiliation(s)
- Ping-hung Chen
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Huiyu Yao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lily Jun-shen Huang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- *Correspondence: Lily Jun-shen Huang,
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Montero D, Rauber S, Goetze JP, Lundby C. Reduction in central venous pressure enhances erythropoietin synthesis: role of volume-regulating hormones. Acta Physiol (Oxf) 2016; 218:89-97. [PMID: 27169519 DOI: 10.1111/apha.12708] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/11/2016] [Accepted: 05/09/2016] [Indexed: 02/04/2023]
Abstract
AIMS Erythropoiesis is a tightly controlled biological event, but its regulation under non-hypoxic conditions, however, remains unresolved. We examined whether acute changes in central venous blood pressure (CVP) elicited by whole-body tilting affect erythropoietin (EPO) concentration according to volume-regulating hormones. METHODS Plasma EPO, angiotensin II (ANGII), aldosterone, pro-atrial natriuretic peptide (proANP) and copeptin concentrations were measured at supine rest and up to 3 h during 30° head-up (HUT) and head-down tilt (HDT) in ten healthy male volunteers. Plasma albumin concentration was used to correct for changes in plasma volume and CVP was estimated through the internal jugular vein (IJV) aspect ratio with ultrasonography. RESULTS From supine rest, the IJV aspect ratio was decreased and increased throughout HUT and HDT respectively. Plasma EPO concentration increased during HUT (13%; P = 0.001, P for linear component = 0.017), independent of changes in albumin concentration. Moreover, ANGII and copeptin concentrations increased during HUT, while proANP decreased. The increase in EPO concentration during HUT disappeared when adjusted for changes in copeptin. During HDT, EPO, ANGII and copeptin concentrations remained unaffected while proANP increased. In regression analyses, EPO was positively associated with copeptin (β = 0.55; 95% CI = 0.18, 0.93; P = 0.004) irrespective of changes in other hormones and albumin concentration. CONCLUSION Reduction in CVP prompts an increase in plasma EPO concentration independent of hemoconcentration and hence suggests CVP per se as an acute regulator of EPO synthesis. This effect may be explained by changes in volume-regulating hormones.
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Affiliation(s)
- D. Montero
- Institute of Physiology; Zurich Center for Integrative Human Physiology (ZIHP); University of Zurich; Zurich Switzerland
| | - S. Rauber
- Institute of Physiology; Zurich Center for Integrative Human Physiology (ZIHP); University of Zurich; Zurich Switzerland
| | - J. P. Goetze
- Department of Clinical Biochemistry; Copenhagen and Aarhus University; Aarhus Denmark
| | - C. Lundby
- Institute of Physiology; Zurich Center for Integrative Human Physiology (ZIHP); University of Zurich; Zurich Switzerland
- Institute of Physiology; National Center of Competence in Research Kidney. CH; University of Zurich; Switzerland
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16
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Krzyzanski W, Harrold JM, Wu LS, Perez-Ruixo JJ. A cell-level model of pharmacodynamics-mediated drug disposition. J Pharmacokinet Pharmacodyn 2016; 43:513-27. [PMID: 27612462 DOI: 10.1007/s10928-016-9491-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/02/2016] [Indexed: 01/22/2023]
Abstract
We aimed to develop a cell-level pharmacodynamics-mediated drug disposition (PDMDD) model to analyze in vivo systems where the PD response to a drug has an appreciable effect on the pharmacokinetics (PK). An existing cellular level model of PD stimulation was combined with the standard target-mediated drug disposition (TMDD) model and the resulting model structure was parametrically identifiable from typical in vivo PK and PD data. The PD model of the cell population was controlled by the production rate k in and elimination rate k out which could be stimulated or inhibited by the number of bound receptors on a single cell. Simulations were performed to assess the impact of single and repeated dosing on the total drug clearance. The clinical utility of the cell-level PDMDD model was demonstrated by fitting published data on the stimulatory effects of filgrastim on absolute neutrophil counts in healthy subjects. We postulated repeated dosing as a means of detecting and quantifying PDMDD as a single dose might not be sufficient to elicit the cellular response capable of altering the receptor pool to visibly affect drug disposition. In the absence of any PD effect, the model reduces down to the standard TMDD model. The applications of this model can be readily extended to include chemotherapy-induced cytopenias affecting clearance of endogenous hematopoietic growth factors, different monoclonal antibodies and immunogenicity effects on PK.
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Affiliation(s)
| | - John M Harrold
- Clinical Pharmacology, Modeling, and Simulation, Amgen Inc., One Amgen Center Dr, Thousand Oaks, CA, 91320, USA.
| | - Liviawati S Wu
- Clinical Pharmacology, Modeling, and Simulation, Amgen Inc., One Amgen Center Dr, Thousand Oaks, CA, 91320, USA
| | - Juan Jose Perez-Ruixo
- Clinical Pharmacology, Modeling, and Simulation, Amgen Inc., One Amgen Center Dr, Thousand Oaks, CA, 91320, USA.,Janssen Research & Development, Beerse, Antwerp, Belgium
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17
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Targeted erythropoietin selectively stimulates red blood cell expansion in vivo. Proc Natl Acad Sci U S A 2016; 113:5245-50. [PMID: 27114509 DOI: 10.1073/pnas.1525388113] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The design of cell-targeted protein therapeutics can be informed by natural protein-protein interactions that use cooperative physical contacts to achieve cell type specificity. Here we applied this approach in vivo to the anemia drug erythropoietin (EPO), to direct its activity to EPO receptors (EPO-Rs) on red blood cell (RBC) precursors and prevent interaction with EPO-Rs on nonerythroid cells, such as platelets. Our engineered EPO molecule was mutated to weaken its affinity for EPO-R, but its avidity for RBC precursors was rescued via tethering to an antibody fragment that specifically binds the human RBC marker glycophorin A (huGYPA). We systematically tested the impact of these engineering steps on in vivo markers of efficacy, side effects, and pharmacokinetics. huGYPA transgenic mice dosed with targeted EPO exhibited elevated RBC levels, with only minimal platelet effects. This in vivo selectivity depended on the weakening EPO mutation, fusion to the RBC-specific antibody, and expression of huGYPA. The terminal plasma half-life of targeted EPO was ∼28.3 h in transgenic mice vs. ∼15.5 h in nontransgenic mice, indicating that huGYPA on mature RBCs acted as a significant drug sink but did not inhibit efficacy. In a therapeutic context, our targeting approach may allow higher restorative doses of EPO without platelet-mediated side effects, and also may improve drug pharmacokinetics. These results demonstrate how rational drug design can improve in vivo specificity, with potential application to diverse protein therapeutics.
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18
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Risør LM, Fenger M, Olsen NV, Møller S. Hepatic erythropoietin response in cirrhosis. A contemporary review. Scandinavian Journal of Clinical and Laboratory Investigation 2016; 76:183-9. [PMID: 26919118 DOI: 10.3109/00365513.2016.1143563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The main function of erythropoietin (EPO) is to maintain red blood cell mass, but in recent years, increasing evidence has suggested a wider biological role not solely related to erythropoiesis, e.g. angiogenesis and tissue protection. EPO is produced in the liver during fetal life, but the main production shifts to the kidney after birth. The liver maintains a production capacity of up to 10% of the total EPO synthesis in healthy controls, but can be up-regulated to 90-100%. However, the hepatic EPO synthesis has been shown not to be adequate for correction of anemia in the absence of renal-derived EPO. Elevated circulating EPO has been reported in a number of diseases, but data from cirrhotic patients are sparse and the level of plasma EPO in patients with cirrhosis is controversial. Cirrhosis is characterized by liver fibrosis, hepatic dysfunction and the release of proinflammatory cytokines, which lead to arterial hypotension, hepatic nephropathy and anemia. An increase in EPO due to renal hypoperfusion, hypoxia and anemia or an EPO-mediated hepato-protective and regenerative mechanism is plausible. However, poor hepatic synthesis capacity, a decreasing co-factor level and inflammatory feedback mechanisms may explain a potential insufficient EPO response in end-stage cirrhosis. Finally, the question remains as to whether a potential increase in EPO production in certain stages of cirrhosis originates from the kidney or liver. This paper aims to review contemporary aspects of EPO relating to chronic liver disease.
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Affiliation(s)
- Louise Madeleine Risør
- a Department of Clinical Physiology and Nuclear Medicine, Center of Functional and Diagnostic Imaging and Research 260 , Hvidovre Hospital, University of Copenhagen
| | - Mogens Fenger
- b Department of Clinical Biochemistry, Hvidovre; Faculty of Health Sciences , University of Copenhagen
| | - Niels Vidiendal Olsen
- c Department of Neuroanaesthesia, the Neuroscience Centre , University Hospital of Copenhagen (Rigshospitalet), and ;,d Department of Neuroscience and Pharmacology, the Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Søren Møller
- a Department of Clinical Physiology and Nuclear Medicine, Center of Functional and Diagnostic Imaging and Research 260 , Hvidovre Hospital, University of Copenhagen
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Lee-Montiel FT, Li P, Imoukhuede PI. Quantum dot multiplexing for the profiling of cellular receptors. NANOSCALE 2015; 7:18504-18514. [PMID: 26377627 DOI: 10.1039/c5nr01455g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The profiling of cellular heterogeneity has wide-reaching importance for our understanding of how cells function and react to their environments in healthy and diseased states. Our ability to interpret and model cell behavior has been limited by the difficulties of measuring cell differences, for example, comparing tumor and non-tumor cells, particularly at the individual cell level. This demonstrates a clear need for a generalizable approach to profile fluorophore sites on cells or molecular assemblies on beads. Here, a multiplex immunoassay for simultaneous detection of five different angiogenic markers was developed. We targeted angiogenic receptors in the vascular endothelial growth factor family (VEGFR1, VEGFR2 and VEGFR3) and Neuropilin (NRP) family (NRP1 and NRP2), using multicolor quantum dots (Qdots). Copper-free click based chemistry was used to conjugate the monoclonal antibodies with 525, 565, 605, 655 and 705 nm CdSe/ZnS Qdots. We tested and performed colocalization analysis of our nanoprobes using the Pearson correlation coefficient statistical analysis. Human umbilical vein endothelial cells (HUVEC) were tested. The ability to easily monitor the molecular indicators of angiogenesis that are a precursor to cancer in a fast and cost effective system is an important step towards personalized nanomedicine.
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Affiliation(s)
- Felipe T Lee-Montiel
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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20
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Sebastian Samuel J, Kumar D, Chodisetti SB, Agrewala JN, Singh B, Guptasarma P, Sarkar D. Probing protease sensitivity of recombinant human erythropoietin reveals α3-α4 inter-helical loop as a stability determinant. Proteins 2015. [PMID: 26214268 DOI: 10.1002/prot.24865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although unglycosylated HuEpo is fully functional, it has very short serum half-life. However, the mechanism of in vivo clearance of human Epo (HuEpo) remains largely unknown. In this study, the relative importance of protease-sensitive sites of recombinant HuEpo (rHuEpo) has been investigated by analysis of structural data coupled with in vivo half-life measurements. Our results identify α3-α4 inter-helical loop region as a target site of lysosomal protease Cathepsin L. Consistent with previously-reported lysosomal degradation of HuEpo, these results for the first time identify cleavage sites of rHuEpo by specific lysosomal proteases. Furthermore, in agreement with the lowered exposure of the peptide backbone around the cleavage site, remarkably substitutions of residues with bulkier amino acids result in significantly improved in vivo stability. Together, these results have implications for the mechanism of in vivo clearance of the protein in humans.
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Affiliation(s)
| | - Deepak Kumar
- CSIR- Institute of Microbial Technology, Sector-39A, Chandigarh, 160036, India
| | | | - Javed N Agrewala
- CSIR- Institute of Microbial Technology, Sector-39A, Chandigarh, 160036, India
| | - Balvinder Singh
- CSIR- Institute of Microbial Technology, Sector-39A, Chandigarh, 160036, India
| | - Purnananda Guptasarma
- Department of Biological Sciences, Indian Institute of Science Education & Research (IISER) Mohali, Punjab, 140306, India
| | - Dibyendu Sarkar
- CSIR- Institute of Microbial Technology, Sector-39A, Chandigarh, 160036, India
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21
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Abstract
Improved understanding of the oxygen-dependent regulation of erythropoiesis has provided new insights into the pathogenesis of anaemia associated with renal failure and has led to the development of novel therapeutic agents for its treatment. Hypoxia-inducible factor (HIF)-2 is a key regulator of erythropoiesis and iron metabolism. HIF-2 is activated by hypoxic conditions and controls the production of erythropoietin by renal peritubular interstitial fibroblast-like cells and hepatocytes. In anaemia associated with renal disease, erythropoiesis is suppressed due to inadequate erythropoietin production in the kidney, inflammation and iron deficiency; however, pharmacologic agents that activate the HIF axis could provide a physiologic approach to the treatment of renal anaemia by mimicking hypoxia responses that coordinate erythropoiesis with iron metabolism. This Review discusses the functional inter-relationships between erythropoietin, iron and inflammatory mediators under physiologic conditions and in relation to the pathogenesis of renal anaemia, as well as recent insights into the molecular and cellular basis of erythropoietin production in the kidney. It furthermore provides a detailed overview of current clinical experience with pharmacologic activators of HIF signalling as a novel comprehensive and physiologic approach to the treatment of anaemia.
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22
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Hypoxia Signaling Cascade for Erythropoietin Production in Hepatocytes. Mol Cell Biol 2015; 35:2658-72. [PMID: 26012551 DOI: 10.1128/mcb.00161-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/22/2015] [Indexed: 01/01/2023] Open
Abstract
Erythropoietin (Epo) is produced in the kidney and liver in a hypoxia-inducible manner via the activation of hypoxia-inducible transcription factors (HIFs) to maintain oxygen homeostasis. Accelerating Epo production in hepatocytes is one plausible therapeutic strategy for treating anemia caused by kidney diseases. To elucidate the regulatory mechanisms of hepatic Epo production, we analyzed mouse lines harboring liver-specific deletions of genes encoding HIF-prolyl-hydroxylase isoforms (PHD1, PHD2, and PHD3) that mediate the inactivation of HIF1α and HIF2α under normal oxygen conditions. The loss of all PHD isoforms results in both polycythemia, which is caused by Epo overproduction, and fatty livers. We found that deleting any combination of two PHD isoforms induces polycythemia without steatosis complications, whereas the deletion of a single isoform induces no apparent phenotype. Polycythemia is prevented by the loss of either HIF2α or the hepatocyte-specific Epo gene enhancer (EpoHE). Chromatin analyses show that the histones around EpoHE dissociate from the nucleosome structure after HIF2α activation. HIF2α also induces the expression of HIF3α, which is involved in the attenuation of Epo production. These results demonstrate that the total amount of PHD activity is more important than the specific function of each isoform for hepatic Epo expression regulated by a PHD-HIF2α-EpoHE cascade in vivo.
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23
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Suzuki N, Mukai HY, Yamamoto M. In vivo regulation of erythropoiesis by chemically inducible dimerization of the erythropoietin receptor intracellular domain. PLoS One 2015; 10:e0119442. [PMID: 25790231 PMCID: PMC4366189 DOI: 10.1371/journal.pone.0119442] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 01/13/2015] [Indexed: 11/18/2022] Open
Abstract
Erythropoietin (Epo) and its receptor (EpoR) are required for the regulation of erythropoiesis. Epo binds to the EpoR homodimer on the surface of erythroid progenitors and erythroblasts, and positions the intracellular domains of the homodimer to be in close proximity with each other. This conformational change is sufficient for the initiation of Epo-EpoR signal transduction. Here, we established a system of chemically regulated erythropoiesis in transgenic mice expressing a modified EpoR intracellular domain (amino acids 247-406) in which dimerization is induced using a specific compound (chemical inducer of dimerization, CID). Erythropoiesis is reversibly induced by oral administration of the CID to the transgenic mice. Because transgene expression is limited to hematopoietic cells by the Gata1 gene regulatory region, the effect of the CID is limited to erythropoiesis without adverse effects. Additionally, we show that the 160 amino acid sequence is the minimal essential domain of EpoR for intracellular signaling of chemically inducible erythropoiesis in vivo. We propose that the CID-dependent dimerization system combined with the EpoR intracellular domain and the Gata1 gene regulatory region generates a novel peroral strategy for the treatment of anemia.
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Affiliation(s)
- Norio Suzuki
- Division of Interdisciplinary Medical Science, Center for Oxygen Medicine, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
- * E-mail:
| | - Harumi Y. Mukai
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
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24
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Pharmacodynamics, pharmacokinetics, and tolerability of intravenous or subcutaneous GC1113, a novel erythropoiesis-stimulating agent. Clin Drug Investig 2015; 34:373-82. [PMID: 24623104 DOI: 10.1007/s40261-014-0183-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND AND OBJECTIVES GC1113, a hybrid Fc-fused erythropoietin, is a novel erythropoiesis-stimulating agent that is expected to have an extended duration of action. The preclinical data showed that the hemoglobin increase lasted longer following GC1113 administration than it did following the administration of darbepoetin alfa (NESP®). This study aimed to investigate the pharmacodynamic and pharmacokinetic characteristics and tolerability profiles of GC1113 in humans after single intravenous or subcutaneous administration and to compare the results with those for darbepoetin alfa. METHODS A dose-block randomized, placebo- and active-controlled, dose-escalation phase I clinical trial was conducted in 96 healthy volunteers. Blood samples were collected before and up to 672 h after drug administration and the serum erythropoietin concentration following the GC1113 or darbepoetin alfa administration was measured by an ELISA. The reticulocyte counts were measured for pharmacodynamic assessments. Pharmacokinetic and pharmacodynamic parameters were determined using non-compartmental methods. RESULTS The reticulocyte count-time profiles in the intravenous GC1113 3-5 μg/kg groups were comparable with those of the darbepoetin alfa 30 μg group. After subcutaneous administration of GC1113, reticulocyte count peaked later and decreased more slowly than it did following darbepoetin alfa administration. GC1113 (0.3-5 μg/kg intravenous, 1-8 μg/kg subcutaneous) was well-tolerated in the volunteers, and no immunogenicity was observed. CONCLUSION GC1113 was tolerated and effective in the studied dose range; these findings could be applied to further clinical studies with patients.
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25
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Lee EJ, Be CL, Vinson AR, Riches AG, Fehr F, Gardiner J, Gengenbach TR, Winkler DA, Haylock D. Immobilisation of a thrombopoietin peptidic mimic by self-assembled monolayers for culture of CD34+ cells. Biomaterials 2015; 37:82-93. [DOI: 10.1016/j.biomaterials.2014.10.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/02/2014] [Indexed: 01/25/2023]
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26
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Vogel M, Blobel M, Thomas A, Walpurgis K, Schänzer W, Reichel C, Thevis M. Isolation, Enrichment, and Analysis of Erythropoietins in Anti-Doping Analysis by Receptor-Coated Magnetic Beads and Liquid Chromatography–Mass Spectrometry. Anal Chem 2014; 86:12014-21. [DOI: 10.1021/ac5024765] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Matthias Vogel
- Center
for Preventive Doping Research/Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
| | - Mike Blobel
- Center
for Preventive Doping Research/Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
| | - Andreas Thomas
- Center
for Preventive Doping Research/Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
| | - Katja Walpurgis
- Center
for Preventive Doping Research/Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
| | - Wilhelm Schänzer
- Center
for Preventive Doping Research/Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
| | - Christian Reichel
- Doping
Control Laboratory, AIT Seibersdorf Laboratories, A-2444 Seibersdorf, Austria
| | - Mario Thevis
- Center
for Preventive Doping Research/Institute of Biochemistry, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany
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27
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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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28
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Abstract
Erythropoietin (Epo) binding to the Epo receptor (EpoR) elicits downstream signaling that is essential for red blood cell production. One important negative regulatory mechanism to terminate Epo signaling is Epo-induced EpoR endocytosis and degradation. Defects in this mechanism play a key role in the overproduction of erythrocytes in primary familial and congenital polycythemia (PFCP). Here we have identified a novel mechanism mediating Epo-dependent EpoR internalization. Epo induces Cbl-dependent ubiquitination of the p85 regulatory subunit of PI3K, which binds to phosphotyrosines on EpoR. Ubiquitination allows p85 to interact with the endocytic protein epsin-1, thereby driving EpoR endocytosis. Knockdown of Cbl, expression of its dominant negative forms, or expression of an epsin-1 mutant devoid of ubiquitin-interacting motifs all compromise Epo-induced EpoR internalization. Mutated EpoRs mimicking those from PFCP patients cannot bind p85, co-localize with epsin-1, or internalize on Epo stimulation and exhibit Epo hypersensitivity. Similarly, knockdown of Cbl also causes Epo hypersensitivity in primary erythroid progenitors. Restoring p85 binding to PFCP receptors rescues Epo-induced epsin-1 co-localization and EpoR internalization and normalizes Epo hypersensitivity. Our results uncover a novel Cbl/p85/epsin-1 pathway in EpoR endocytosis and show that defects in this pathway contribute to excessive Epo signaling and erythroid hyperproliferation in PFCP.
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Jelkmann I, Jelkmann W. Impact of erythropoietin on intensive care unit patients. ACTA ACUST UNITED AC 2013; 40:310-8. [PMID: 24273484 DOI: 10.1159/000354128] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/06/2013] [Indexed: 12/13/2022]
Abstract
Anemia is common in intensive care unit (ICU) patients. Red blood cell (RBC) transfusions are mainstays of their treatment and can be life-saving. Allogeneic blood components inherently bear risks of infection and immune reactions. Although these risks are rare in developed countries, recombinant human erythropoietin (rhEpo) and other erythropoiesis-stimulating agents (ESAs) have been considered alternative anti-anemia treatment options. As summarized herein, however, most of the clinical studies suggest that ESAs are not usually advisable in ICU patients unless approved indications exist (e.g., renal disease). First, ESAs act in a delayed way, inducing an increase in reticulocytes only after a lag of 3-4 days. Second, many critically ill patients present with ESA resistance as inflammatory mediators impair erythropoietic cell proliferation and iron availability. Third, the ESA doses used for treatment of ICU patients are very high. Fourth, ESAs are not legally approved for general use in ICU patients. Solely in distinct cases, such as Jehovah's Witnesses who refuse allogeneic blood transfusions due to religious beliefs, ESAs may be considered an exceptional therapy.
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Affiliation(s)
- Ines Jelkmann
- Department of Surgery, University of Lübeck, Germany
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30
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Yan X, Krzyzanski W. Quantitative assessment of minimal effective concentration of erythropoiesis-stimulating agents. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2013; 2:e62. [PMID: 23924820 PMCID: PMC3828003 DOI: 10.1038/psp.2013.39] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 05/29/2013] [Indexed: 11/09/2022]
Abstract
Minimal effective concentration (MEC) was proposed to explain why subcutaneous (SC) administration of erythropoietin (EPO) induces a higher hemoglobin (HGB) increase than intravenous (IV) administration. It has been further used to explain the paradox that erythropoiesis-stimulating agent (ESA) with lower receptor binding affinity may have higher in vivo activity. We have developed a pharmacokinetic and pharmacodynamic (PK/PD) model with incorporation of the operational model of agonism to characterize the data from two clinical trials. By using model-based simulations, we demonstrate that SC route is more efficacious than IV route and explain the paradoxical behavior of ESAs. We determined that MEC can be quantified by C50, which represents the concentration of an ESA producing its half-maximal effect of stimulating the proliferation of erythroid precursor cells. The model used may allow joint PK/PD modeling of data from different ESAs, and provide a platform for dosing regimen optimizations and future clinical study designs.CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e62; doi:10.1038/psp.2013.39; published online 7 August 2013.
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Affiliation(s)
- X Yan
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, USA
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Abstract
Renal anemia has been recognized as a characteristic complication of chronic kidney disease. Although many factors are involved in renal anemia, the predominant cause of renal anemia is a relative deficiency in erythropoietin (EPO) production. To date, exogenous recombinant human (rh)EPO has been widely used as a powerful drug for the treatment of patients with renal anemia. Despite its clinical effectiveness, a potential risk for increased mortality has been suggested in patients who receive rhEPO, in addition to the economic burden of rhEPO administration. The induction of endogenous EPO is another therapeutic approach that might have advantages over rhEPO administration. However, the physiological and pathophysiological regulation of EPO are not fully understood, and this lack of understanding has hindered the development of an endogenous EPO inducer. In this review, we will discuss the current treatment for renal anemia and its drawbacks, provide an overview of EPO regulation in healthy and diseased conditions, and propose future directions for therapeutic trials that more directly target the underlying pathophysiology of renal anemia.
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Affiliation(s)
- Yuki Sato
- 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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Jelkmann W. Physiology and pharmacology of erythropoietin. ACTA ACUST UNITED AC 2013; 40:302-9. [PMID: 24273483 DOI: 10.1159/000356193] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/03/2013] [Indexed: 12/13/2022]
Abstract
Human erythropoietin (Epo) is a 30.4 kDa glycoprotein hormone composed of a single 165 amino acid residues chain to which four glycans are attached. The kidneys are the primary sources of Epo, its synthesis is controlled by hypoxia-inducible transcription factors (HIFs). Epo is an essential factor for the viability and proliferation of erythrocytic progenitors. Whether Epo exerts cytoprotection outside the bone marrow still needs to be clarified. Epo deficiency is the primary cause of the anemia in chronic kidney disease (CKD). Treatment with recombinant human Epo (rhEpo, epoetin) can be beneficial not only in CKD but also for other indications, primarily anemia in cancer patients receiving chemotherapy. Considering unwanted events, the administration of rhEpo or its analogs may increase the incidence of thromboembolism. The expiry of the patents for the original epoetins has initiated the production of similar biological medicinal products ('biosimilars'). Furthermore, analogs (darbepoetin alfa, methoxy PEG-epoetin beta) with prolonged survival in circulation have been developed ('biobetter'). New erythropoiesis-stimulating agents are in clinical trials. These include compounds that augment erythropoiesis directly (e.g. Epo mimetic peptides or activin A binding protein) and chemicals that act indirectly by stimulating endogenous Epo synthesis (HIF stabilizers).
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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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Abstract
INTRODUCTION Erythropoiesis-stimulating agents (ESAs) are the mainstay of treatment in anemic chronic kidney disease (CKD) patients. A tailored ESA therapy should combine maximal efficacy and safety with greatest convenience in dosing. Peginesatide, recently approved in the US for once-monthly dosing in adult patients on dialysis, is a promising novel PEGylated erythropoietin-mimetic peptide for the treatment of renal disease-induced anemia. AREAS COVERED Published animal and human studies that evaluated the pharmacodynamics, pharmacokinetics, clinical efficacy and safety of peginesatide were critically analyzed. EXPERT OPINION Peginesatide has a well-studied pharmacological and immunological profile, and latest published data favor the use of peginesatide in place of epoetin in dialysis patients. A more detailed evaluation of its safety profile particularly in trials with CKD patients not requiring dialysis is urgently needed, as peginesatide could be a perfect treatment solution for these patients. In addition, clinical long-term data and results from supplemental studies, e.g., with the PEGylated continuous erythropoietin receptor activator as comparator, should briefly follow. The fate of peginesatide on the highly competitive ESA market is currently not predictable and depends on safety and efficacy results of upcoming trials as well as finally on market and price policy.
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Affiliation(s)
- Holger Schmid
- University of Munich, Department of Internal Medicine, Munich, D-80336, Germany.
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Heparan Sulfate Regrowth Profiles Under Laminar Shear Flow Following Enzymatic Degradation. Cell Mol Bioeng 2013; 6:160-174. [PMID: 23805169 PMCID: PMC3689914 DOI: 10.1007/s12195-013-0273-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 02/07/2013] [Indexed: 11/17/2022] Open
Abstract
The local hemodynamic shear stress waveforms present in an artery dictate the endothelial cell phenotype. The observed decrease of the apical glycocalyx layer on the endothelium in atheroprone regions of the circulation suggests that the glycocalyx may have a central role in determining atherosclerotic plaque formation. However, the kinetics for the cells’ ability to adapt its glycocalyx to the environment have not been quantitatively resolved. Here we report that the heparan sulfate component of the glycocalyx of HUVECs increases by 1.4-fold following the onset of high shear stress, compared to static cultured cells, with a time constant of 19 h. Cell morphology experiments show that 12 h are required for the cells to elongate, but only after 36 h have the cells reached maximal alignment to the flow vector. Our findings demonstrate that following enzymatic degradation, heparan sulfate is restored to the cell surface within 12 h under flow whereas the time required is 20 h under static conditions. We also propose a model describing the contribution of endocytosis and exocytosis to apical heparan sulfate expression. The change in HS regrowth kinetics from static to high-shear EC phenotype implies a differential in the rate of endocytic and exocytic membrane turnover.
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Regulation of Erythropoietin Receptor Activity in Endothelial Cells by Different Erythropoietin (EPO) Derivatives: An in Vitro Study. Int J Mol Sci 2013; 14:2258-81. [PMID: 23348925 PMCID: PMC3587987 DOI: 10.3390/ijms14022258] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 12/20/2012] [Accepted: 01/11/2013] [Indexed: 12/20/2022] Open
Abstract
In endothelial cells, erythropoietin receptors (EPORs) mediate the protective, proliferative and angiogenic effects of EPO and its analogues, which act as EPOR agonists. Because hormonal receptors undergo functional changes upon chronic exposure to agonists and because erythropoiesis-stimulating agents (ESAs) are used for the long-term treatment of anemia, it is critical to determine the mechanism by which EPOR responsiveness is regulated at the vascular level after prolonged exposure to ESAs. Here, we investigated EPOR desensitization/resensitization in human umbilical vein endothelial cells (HUVECs) upon exposure to three ESAs with different pharmacokinetic profiles, epoetin alpha (EPOα), darbepoetin alpha (DarbEPO) and continuous EPOR activator (CERA). These agonists all induced activation of the transcription factor STAT-5, which is a component of the intracellular pathway associated with EPORs. STAT-5 activation occurred with either monophasic or biphasic kinetics for EPOα/DarbEPO and CERA, respectively. ESAs, likely through activation of the STAT-5 pathway, induced endothelial cell proliferation and stimulated angiogenesis in vitro, demonstrating a functional role for epoetins on endothelial cells. All epoetins induced EPOR desensitization with more rapid kinetics for CERA compared to EPOα and DarbEPO. However, the recovery of receptor responsiveness was strictly dependent on the type of epoetin, the agonist concentration and the time of exposure to the agonist. EPOR resensitization occurred with more rapid kinetics after exposure to low epoetin concentrations for a short period of desensitization. When the highest concentration of agonists was tested, the recovery of receptor responsiveness was more rapid with CERA compared to EPOα and was completely absent with DarbEPO. Our results demonstrate that these three ESAs regulate EPOR resensitization by very different mechanisms and that both the type of molecule and the length of EPOR stimulation are factors that are critical for the control of EPOR functioning in endothelial cells. The differences observed in receptor resensitization after stimulation with the structurally different ESAs are most likely due different control mechanisms of receptor turnover at the intracellular level.
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Abstract
The hematopoietic growth factor erythropoietin (Epo) circulates in plasma and controls the oxygen carrying capacity of the blood (Fisher. Exp Biol Med (Maywood) 228:1-14, 2003). Epo is produced primarily in the adult kidney and fetal liver and was originally believed to play a role restricted to stimulation of early erythroid precursor proliferation, inhibition of apoptosis, and differentiation of the erythroid lineage. Early studies showed that mice with targeted deletion of Epo or the Epo receptor (EpoR) show impaired erythropoiesis, lack mature erythrocytes, and die in utero around embryonic day 13.5 (Wu et al. Cell 83:59-67, 1995; Lin et al. Genes Dev. 10:154-164, 1996). These animals also exhibited heart defects, abnormal vascular development as well as increased apoptosis in the brain suggesting additional functions for Epo signaling in normal development of the central nervous system and heart. Now, in addition to its well-known role in erythropoiesis, a diverse array of cells have been identified that produce Epo and/or express the Epo-R including endothelial cells, smooth muscle cells, and cells of the central nervous system (Masuda et al. J Biol Chem. 269:19488-19493, 1994; Marti et al. Eur J Neurosci. 8:666-676, 1996; Bernaudin et al. J Cereb Blood Flow Metab. 19:643-651, 1999; Li et al. Neurochem Res. 32:2132-2141, 2007). Endogenously produced Epo and/or expression of the EpoR gives rise to autocrine and paracrine signaling in different organs particularly during hypoxia, toxicity, and injury conditions. Epo has been shown to regulate a variety of cell functions such as calcium flux (Korbel et al. J Comp Physiol B. 174:121-128, 2004) neurotransmitter synthesis and cell survival (Velly et al. Pharmacol Ther. 128:445-459, 2010; Vogel et al. Blood. 102:2278-2284, 2003). Furthermore Epo has neurotrophic effects (Grimm et al. Nat Med. 8:718-724, 2002; Junk et al. Proc Natl Acad Sci U S A. 99:10659-10664, 2002), can induce an angiogenic phenotype in cultured endothelial cells and is a potent angiogenic factor in vivo (Ribatti et al. Eur J Clin Invest. 33:891-896, 2003) and might enhance ventilation in hypoxic conditions (Soliz et al. J Physiol. 568:559-571, 2005; Soliz et al. J Physiol. 583, 329-336, 2007). Thus multiple functions have been identified breathing new life and exciting possibilities into what is really an old growth factor.This review will address the function of Epo in non-hematopoietic tissues with significant emphasis on the brain and heart.
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Affiliation(s)
- Omolara O Ogunshola
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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Dewamitta SR, Russell MR, Nandurkar H, Walkley CR. Darbepoietin-alfa has comparable erythropoietic stimulatory effects to recombinant erythropoietin whilst preserving the bone marrow microenvironment. Haematologica 2012; 98:686-90. [PMID: 23242598 DOI: 10.3324/haematol.2012.078709] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Erythropoiesis stimulating agents are widely used for the treatment of anemia. Recently, we reported erythroid expansion with impaired B lymphopoiesis and loss of trabecular bone in C57BL/6 mice following ten days of treatment with low-dose short acting recombinant human erythropoietin. We have assessed erythropoietin against longer-acting darbepoietin-alfa at a comparable erythroid stimulatory dosage regime. Darbepoietin-alfa and erythropoietin induced similar in vivo erythropoietic expansion. Both agents induced an expansion of the colony-forming unit-erythroid populations. However, unlike erythropoietin, darbepoietin-alfa did not impair bone marrow B lymphopoiesis. Strikingly the bone loss observed with erythropoietin was not apparent following darbepoietin-alfa treatment. This analysis demonstrates that whilst darbepoietin-alfa has similar in vivo erythropoietic potency to erythropoietin, it preserves the bone marrow microenvironment. Thus erythropoietin and darbepoietin-alfa manifest different action showing that erythropoiesis stimulating agents have differential non-erythroid effects dependent on their duration of action.
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Affiliation(s)
- Sita R Dewamitta
- St Vincent’s Institute of Medical Research and Department of Medicine at St. Vincent’s Hospital, University of Melbourne, Fitzroy,Victoria, Australia
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Yan X, Chen Y, Krzyzanski W. Methods of solving rapid binding target-mediated drug disposition model for two drugs competing for the same receptor. J Pharmacokinet Pharmacodyn 2012; 39:543-60. [PMID: 22926955 DOI: 10.1007/s10928-012-9267-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 07/23/2012] [Indexed: 11/25/2022]
Abstract
The target-mediated drug disposition (TMDD) model has been adopted to describe pharmacokinetics for two drugs competing for the same receptor. A rapid binding assumption introduces total receptor and total drug concentrations while free drug concentrations C (A) and C (B) are calculated from the equilibrium (Gaddum) equations. The Gaddum equations are polynomials in C (A) and C (B) of second degree that have explicit solutions involving complex numbers. The aim of this study was to develop numerical methods to solve the rapid binding TMDD model for two drugs competing for the same receptor that can be implemented in pharmacokinetic software. Algebra, calculus, and computer simulations were used to develop algorithms and investigate properties of solutions to the TMDD model with two drugs competitively binding to the same receptor. A general rapid binding approximation of the TMDD model for two drugs competing for the same receptor has been proposed. The explicit solutions to the equilibrium equations employ complex numbers, which cannot be easily solved by pharmacokinetic software. Numerical bisection algorithm and differential representation were developed to solve the system instead of obtaining an explicit solution. The numerical solutions were validated by MATLAB 7.2 solver for polynomial roots. The applicability of these algorithms was demonstrated by simulating concentration-time profiles resulting from exogenous and endogenous IgG competing for the neonatal Fc receptor (FcRn), and darbepoetin competing with endogenous erythropoietin for the erythropoietin receptor. These models were implemented in ADAPT 5 and Phoenix WinNonlin 6.0, respectively.
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Affiliation(s)
- Xiaoyu Yan
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14260, USA
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41
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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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Hernández C, Simó R. Erythropoietin produced by the retina: its role in physiology and diabetic retinopathy. Endocrine 2012; 41:220-6. [PMID: 22167324 DOI: 10.1007/s12020-011-9579-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 12/01/2011] [Indexed: 12/22/2022]
Abstract
Erythropoietin (Epo) is the principal regulator of erythropoiesis by inhibiting apoptosis and by stimulating the proliferation and differentiation of erythroid precursor cells. However, Epo also performs extra-erythropoietic actions of which the neuroprotective effects are among the most relevant. Apart from kidney and liver, Epo is also produced by the brain and the retina. In addition, Epo receptor (Epo-R) expression has also been found in the brain and in the retina, thus suggesting an autocrine/paracrine action which seems essential for the physiological homeostasis of both brain and retina. In this review, we will give an overview of the current concepts of the physiology of Epo and will focus on its role in the retina in both normal conditions and in the setting of diabetic retinopathy. Finally, the reasons as to why Epo could be contemplated as a potential new treatment for the early stages of diabetic retinopathy will be given.
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Affiliation(s)
- Cristina Hernández
- CIBERDEM, Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
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Abstract
Reliable inter- and intracellular communication is central to both the development and the integrity of multicellular organisms. Key mediators of these processes are cell surface receptors that perceive and convert extracellular cues to trigger intracellular signaling networks and ultimately a phenotypic response. Deregulation of signal transduction leads to a variety of diseases, and aberrations in receptor proteins are very common in various cancer types. Therefore, cell surface receptors have been established as major targets in drug discovery. However, in order to efficiently apply therapeutics, it is crucial to gain knowledge about design principles of receptor signaling. In this chapter, we will discuss signal transduction at the receptor level for examples from different receptor classes.
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Yan X, Lowe PJ, Fink M, Berghout A, Balser S, Krzyzanski W. Population pharmacokinetic and pharmacodynamic model-based comparability assessment of a recombinant human Epoetin Alfa and the Biosimilar HX575. J Clin Pharmacol 2011; 52:1624-44. [PMID: 22162538 DOI: 10.1177/0091270011421911] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to develop an integrated pharmacokinetic and pharmacodynamic (PK/PD) model and assess the comparability between epoetin alfa HEXAL/Binocrit (HX575) and a comparator epoetin alfa by a model-based approach. PK/PD data-including serum drug concentrations, reticulocyte counts, red blood cells, and hemoglobin levels-were obtained from 2 clinical studies. In sum, 149 healthy men received multiple intravenous or subcutaneous doses of HX575 (100 IU/kg) and the comparator 3 times a week for 4 weeks. A population model based on pharmacodynamics-mediated drug disposition and cell maturation processes was used to characterize the PK/PD data for the 2 drugs. Simulations showed that due to target amount changes, total clearance may increase up to 2.4-fold as compared with the baseline. Further simulations suggested that once-weekly and thrice-weekly subcutaneous dosing regimens would result in similar efficacy. The findings from the model-based analysis were consistent with previous results using the standard noncompartmental approach demonstrating PK/PD comparability between HX575 and comparator. However, due to complexity of the PK/PD model, control of random effects was not straightforward. Whereas population PK/PD model-based analyses are suited for studying complex biological systems, such models have their limitations (statistical), and their comparability results should be interpreted carefully.
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Affiliation(s)
- Xiaoyu Yan
- Department of Pharmaceutical Sciences, 565 B Hochstetter Hall, State University of New York at Buffalo, Buffalo, NY 14260, USA
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Agoram BM, Demin O. Integration not isolation: arguing the case for quantitative and systems pharmacology in drug discovery and development. Drug Discov Today 2011; 16:1031-6. [DOI: 10.1016/j.drudis.2011.10.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 09/26/2011] [Accepted: 10/05/2011] [Indexed: 11/28/2022]
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Maleki A, Madadkar-Sobhani A, Roohvand F, Najafabadi AR, Shafiee A, Khanahmad H, Cohan RA, Namvar N, Tajerzadeh H. Design, modeling, and expression of erythropoietin cysteine analogs in Pichia pastoris: improvement of mean residence times and in vivo activities through cysteine-specific PEGylation. Eur J Pharm Biopharm 2011; 80:499-507. [PMID: 22068050 DOI: 10.1016/j.ejpb.2011.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 10/16/2011] [Accepted: 10/24/2011] [Indexed: 11/16/2022]
Abstract
In this study, the low-cost production of recombinant human erythropoietin cysteine analogs (Cys-rhEPOs) from Pichia pastoris and the potential to increase their serum residency and in vivo activity through cysteine-specific PEGylation were investigated. Three-dimensional structures of several Cys-rhEPOs were generated using homology modeling, and three stable Cys-rhEPOs were selected on the basis of model stability in molecular dynamics simulation and surface accessibility of the inserted cysteine. cDNAs encoding Cys-rhEPOs were constructed by site-directed mutagenesis and expressed as secreted proteins in flask cultures of P. pastoris. The selection of highly expressing clones and the optimization of certain culture parameters resulted in protein expression levels of 100-170 mg/l. Purified Cys-rhEPOs were cysteine-specifically PEGylated using 20 kDa and 30 kDa mPEG-maleimides (methoxy polyethylene glycol-maleimides). The E89CEPO analog with the highest (96.6%) cysteine accessibility was conjugated to PEG-polymers with the largest yields (about 80%). In comparison with rhEPO, 30 kDa PEG-E89CEPO demonstrated a significant (approximately 30%) increase in the mean residence time. Whereas the in vitro activities of 30 kDa PEG-E89CEPO were comparable to those of rhEPO, the in vivo activity of this conjugate was more prolonged compared to rhEPO (12 days vs. 7 days). Our results demonstrate that the site-specific PEGylation of Pichia-expressed EPO analogs may be considered as a promising approach for generating cost-effective and long-acting erythropoiesis-stimulating agents.
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Affiliation(s)
- Ahmad Maleki
- Department of Pharmaceutics, The Tehran University of Medical Science, Tehran, Iran
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Nordsletten DA, Yankama B, Umeton R, Ayyadurai VAS, Dewey CF. Multiscale mathematical modeling to support drug development. IEEE Trans Biomed Eng 2011; 58:3508-12. [PMID: 22042123 DOI: 10.1109/tbme.2011.2173245] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
It is widely recognized that major improvements are required in the methods currently being used to develop new therapeutic drugs. The time from initial target identification to commercialization can be 10-14 years and incur a cost in the hundreds of millions of dollars. Even after substantial investment, only 30-40% of the candidate compounds entering clinical trials are successful. We propose that multiscale mathematical pathway modeling can be used to decrease time required to bring candidate drugs to clinical trial and increase the probability that they will be successful in humans. The requirements for multiple time scales and spatial scales are discussed, and new computational paradigms are identified to address the increased complexity of modeling.
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Im SJ, Yang SI, Yang SH, Choi DH, Choi SY, Kim HS, Jang DS, Jin KS, Chung YK, Kim SH, Paik SH, Park YC, Chung MK, Kim YB, Han KH, Choi KY, Sung YC. Natural form of noncytolytic flexible human Fc as a long-acting carrier of agonistic ligand, erythropoietin. PLoS One 2011; 6:e24574. [PMID: 21957455 PMCID: PMC3174958 DOI: 10.1371/journal.pone.0024574] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 08/14/2011] [Indexed: 12/27/2022] Open
Abstract
Human IgG1 Fc has been widely used as a bioconjugate, but exhibits shortcomings, such as antibody- and complement-mediated cytotoxicity as well as decreased bioactivity, when applied to agonistic proteins. Here, we constructed a nonimmunogenic, noncytolytic and flexible hybrid Fc (hyFc) consisting of IgD and IgG4, and tested its function using erythropoietin (EPO) conjugate, EPO-hyFc. Despite low amino acid homology (20.5%) between IgD Fc and IgG4 Fc, EPO-hyFc retained “Y-shaped” structure and repeated intravenous administrations of EPO-hyFc into monkeys did not generate EPO-hyFc-specific antibody responses. Furthermore, EPO-hyFc could not bind to FcγR I and C1q in contrast to EPO-IgG1 Fc. In addition, EPO-hyFc exhibited better in vitro bioactivity and in vivo bioactivity in rats than EPO-IgG1 Fc, presumably due to the high flexibility of IgD. Moreover, the mean serum half-life of EPO-hyFc(H), a high sialic acid content form of EPO-hyFc, was approximately 2-fold longer than that of the heavily glycosylated EPO, darbepoetin alfa, in rats. More importantly, subcutaneous injection of EPO-hyFc(H) not only induced a significantly greater elevation of serum hemoglobin levels than darbepoetin alfa in both normal rats and cisplatin-induced anemic rats, but also displayed a delayed time to maximal serum level and twice final area-under-the-curve (AUClast). Taken together, hyFc might be a more attractive Fc conjugate for agonistic proteins/peptides than IgG1 Fc due to its capability to elongate their half-lives without inducing host effector functions and hindering bioactivity of fused molecules. Additionally, a head-to-head comparison demonstrated that hyFc-fusion strategy more effectively improved the in vivo bioactivity of EPO than the hyperglycosylation approach.
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Affiliation(s)
- Se Jin Im
- Division of Molecular and Life Sciences, POSTECH, Pohang, Republic of Korea
| | - Sang In Yang
- Research Institute, Genexine Co., Seongnam, Republic of Korea
| | - Se Hwan Yang
- Research Institute, Genexine Co., Seongnam, Republic of Korea
| | - Dong Hoon Choi
- Division of Molecular and Life Sciences, POSTECH, Pohang, Republic of Korea
| | - So Young Choi
- Research Institute, Genexine Co., Seongnam, Republic of Korea
| | - Hea Sook Kim
- Research Institute, Genexine Co., Seongnam, Republic of Korea
| | - Do Soo Jang
- Research Institute, Genexine Co., Seongnam, Republic of Korea
| | - Kyeong Sik Jin
- Pohang Accelerator Laboratory, POSTECH, Pohang, Republic of Korea
| | - Yo-Kyung Chung
- Central Research Institute, Green Cross Co., Yongin, Republic of Korea
| | - Seung-Hee Kim
- Central Research Institute, Green Cross Co., Yongin, Republic of Korea
| | - Sang Hoon Paik
- Central Research Institute, Green Cross Co., Yongin, Republic of Korea
| | - Yoo Chang Park
- Central Research Institute, Green Cross Co., Yongin, Republic of Korea
| | - Moon Koo Chung
- Korea Institute of Toxicology, Korea Research Institute of Chemical Technology, Daejon, Republic of Korea
| | - Yong Bum Kim
- Korea Institute of Toxicology, Korea Research Institute of Chemical Technology, Daejon, Republic of Korea
| | - Kang-Hyun Han
- Korea Institute of Toxicology, Korea Research Institute of Chemical Technology, Daejon, Republic of Korea
| | - Kwan Yong Choi
- Division of Molecular and Life Sciences, POSTECH, Pohang, Republic of Korea
| | - Young Chul Sung
- Division of Molecular and Life Sciences, POSTECH, Pohang, Republic of Korea
- Research Institute, Genexine Co., Seongnam, Republic of Korea
- * E-mail:
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Maleki A, Najafabadi AR, Roohvand F, Shafiee A, Khanahmad H, Faghihi H, Hedayati MH, Tajerzadeh H. Evaluation of Bioactivity and Pharmacokinetic Characteristics of PEGylatedP.pastoris-Expressed Erythropoietin. Drug Deliv 2011; 18:570-7. [DOI: 10.3109/10717544.2011.600782] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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50
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Division of labor by dual feedback regulators controls JAK2/STAT5 signaling over broad ligand range. Mol Syst Biol 2011; 7:516. [PMID: 21772264 PMCID: PMC3159971 DOI: 10.1038/msb.2011.50] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 06/10/2011] [Indexed: 02/06/2023] Open
Abstract
Cellular signal transduction is governed by multiple feedback mechanisms to elicit robust cellular decisions. The specific contributions of individual feedback regulators, however, remain unclear. Based on extensive time-resolved data sets in primary erythroid progenitor cells, we established a dynamic pathway model to dissect the roles of the two transcriptional negative feedback regulators of the suppressor of cytokine signaling (SOCS) family, CIS and SOCS3, in JAK2/STAT5 signaling. Facilitated by the model, we calculated the STAT5 response for experimentally unobservable Epo concentrations and provide a quantitative link between cell survival and the integrated response of STAT5 in the nucleus. Model predictions show that the two feedbacks CIS and SOCS3 are most effective at different ligand concentration ranges due to their distinct inhibitory mechanisms. This divided function of dual feedback regulation enables control of STAT5 responses for Epo concentrations that can vary 1000-fold in vivo. Our modeling approach reveals dose-dependent feedback control as key property to regulate STAT5-mediated survival decisions over a broad range of ligand concentrations.
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