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Clerc OF, Vijayakumar S, Dorbala S. Radionuclide Imaging of Cardiac Amyloidosis: An Update and Future Aspects. Semin Nucl Med 2024; 54:717-732. [PMID: 38960850 DOI: 10.1053/j.semnuclmed.2024.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 05/27/2024] [Accepted: 05/30/2024] [Indexed: 07/05/2024]
Abstract
Cardiac amyloidosis (CA) is caused by the misfolding, accumulation and aggregation of proteins into large fibrils in the extracellular compartment of the myocardium, leading to restrictive cardiomyopathy, heart failure and death. The major forms are transthyretin (ATTR) CA and light-chain (AL) CA, based on the respective precursor protein. Each of them requires early diagnosis for a timely treatment initiation that will improve patient outcomes. For this, radionuclide imaging is essentially used as single-photon emission computed tomography (SPECT) with bone-avid radiotracers or as positron emission tomography (PET) with amyloid-binding radiotracers. Both offer unprecedented specificity for the diagnostic of CA. SPECT has even revolutionized the diagnosis of ATTR-CA by making it non-invasive. Indeed, SPECT has now entered the standard diagnostic pathway to CA and has led to earlier diagnosis of the disease. SPECT also modified the epidemiology of ATTR-CA, highlighting that the disease is much more frequent than previously believed, and showing that ATTR-CA plays a substantial role in HFpEF and aortic stenosis, particularly among elderly patients. In parallel, amyloid-binding radiotracers for PET have accumulated a substantial amount of evidence, but are not approved for clinical use in CA yet. Further studies are needed to refine acquisition protocols and validate results in broader populations. Unlike bone-avid SPECT radiotracers, PET radiotracers have been specifically created to bind to amyloid fibrils. Thus, PET is the only imaging method that is truly specific for amyloid deposits and very sensitive to any amyloid type. Indeed, PET can not only detect ATTR-CA, but also AL-CA and rare hereditary forms. For both SPECT and PET, advances in quantitation of myocardial uptake have generated more granular and reproducible findings, paving the way for progress in earlier diagnosis, risk stratification and therapeutic response monitoring. Encouraging findings have shown that SPECT and PET are sensitive to early CA when other diagnostic methods are negative. Both radionuclide imaging techniques can predict adverse outcomes, but more evidence is needed to determine how to use them in conjunction with usual prognostic staging scores. Studies on follow-up imaging after therapy suggested that SPECT and PET can capture myocardial changes in CA, but again, more data are needed to meaningfully interpret such changes. Based on all these promising results, radionuclide imaging has the potential to further impact the landscape of CA in diagnosis, prognosis and follow-up, but also to substantially contribute to the assessment of novel therapies that will improve the lives of patients with CA.
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Affiliation(s)
- Olivier F Clerc
- Division of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital, Boston, MA; Cardiac Amyloidosis Program, Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Boston, MA
| | - Shilpa Vijayakumar
- Division of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital, Boston, MA; Cardiac Amyloidosis Program, Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Boston, MA
| | - Sharmila Dorbala
- Division of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital, Boston, MA; Cardiac Amyloidosis Program, Division of Cardiology, Department of Medicine, Brigham and Women's Hospital, Boston, MA; CV Imaging Program, Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, Boston, MA.
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Martin EB, Stuckey A, Powell D, Lands R, Whittle B, Wooliver C, Macy S, Foster JS, Guthrie S, Kennel SJ, Wall JS. Clinical Confirmation of Pan-Amyloid Reactivity of Radioiodinated Peptide 124I-p5+14 (AT-01) in Patients with Diverse Types of Systemic Amyloidosis Demonstrated by PET/CT Imaging. Pharmaceuticals (Basel) 2023; 16:629. [PMID: 37111386 PMCID: PMC10144944 DOI: 10.3390/ph16040629] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/14/2023] [Accepted: 04/16/2023] [Indexed: 04/29/2023] Open
Abstract
There are at least 20 distinct types of systemic amyloidosis, all of which result in the organ-compromising accumulation of extracellular amyloid deposits. Amyloidosis is challenging to diagnose due to the heterogeneity of the clinical presentation, yet early detection is critical for favorable patient outcomes. The ability to non-invasively and quantitatively detect amyloid throughout the body, even in at-risk populations, before clinical manifestation would be invaluable. To this end, a pan-amyloid-reactive peptide, p5+14, has been developed that is capable of binding all types of amyloid. Herein, we demonstrate the ex vivo pan-amyloid reactivity of p5+14 by using peptide histochemistry on animal and human tissue sections containing various types of amyloid. Furthermore, we present clinical evidence of pan-amyloid binding using iodine-124-labeled p5+14 in a cohort of patients with eight (n = 8) different types of systemic amyloidosis. These patients underwent PET/CT imaging as part of the first-in-human Phase 1/2 clinical trial evaluating this radiotracer (NCT03678259). The uptake of 124I-p5+14 was observed in abdominothoracic organs in patients with all types of amyloidosis evaluated and was consistent with the disease distribution described in the medical record and literature reports. On the other hand, the distribution in healthy subjects was consistent with radiotracer catabolism and clearance. The early and accurate diagnosis of amyloidosis remains challenging. These data support the utility of 124I-p5+14 for the diagnosis of varied types of systemic amyloidosis by PET/CT imaging.
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Affiliation(s)
- Emily B. Martin
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | - Alan Stuckey
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | - Dustin Powell
- Department of Radiology, University of Tennessee Medical Center, Knoxville, TN 37920, USA
| | - Ronald Lands
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | - Bryan Whittle
- Department of Radiology, University of Tennessee Medical Center, Knoxville, TN 37920, USA
| | - Craig Wooliver
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | - Sallie Macy
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | - James S. Foster
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | | | - Stephen J. Kennel
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
| | - Jonathan S. Wall
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA (J.S.F.); (S.J.K.); (J.S.W.)
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3
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Wall JS, Martin EB, Endsley A, Stuckey AC, Williams AD, Powell D, Whittle B, Hall S, Lambeth TR, Julian RR, Stabin M, Lands RH, Kennel SJ. First in Human Evaluation and Dosimetry Calculations for Peptide 124I-p5+14-a Novel Radiotracer for the Detection of Systemic Amyloidosis Using PET/CT Imaging. Mol Imaging Biol 2021; 24:479-488. [PMID: 34786667 DOI: 10.1007/s11307-021-01681-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/06/2021] [Accepted: 11/01/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Accurate diagnosis of amyloidosis remains a significant clinical challenge and unmet need for patients. The amyloid-reactive peptide p5+14 radiolabeled with iodine-124 has been developed for the detection of amyloid by PET/CT imaging. In a first-in-human evaluation, the dosimetry and tissue distribution of 124I-p5+14 peptide in patients with systemic amyloidosis. Herein, we report the dosimetry and dynamic distribution in the first three enrolled patients with light chain-associated (AL) amyloidosis. PROCEDURES The radiotracer was assessed in a single-site, open-label phase 1 study (NCT03678259). The first three patients received a single intravenous infusion of 124I-p5+14 peptide (≤37 MBq). Serial PET/CT imaging was performed during the 48 h post-infusion. Dosimetry was determined as a primary endpoint for each patient and gender-averaged mean values were calculated. Pharmacokinetic parameters were estimated from whole blood radioactivity measurements and organ-based time activity data. Lastly, the biodistribution of radiotracer in major organs was assessed visually and compared to clinically appreciated organ involvement. RESULTS Infusion of the 124I-p5+14 was well tolerated with rapid uptake in the heart, kidneys, liver, spleen, pancreas, and lung. The gender-averaged whole-body effective radiation dose was estimated to be 0.23 (± 0.02) mSv/MBq with elimination of the radioactivity via renal and gastrointestinal routes. The whole blood elimination t1/2 of 21.9 ± 7.6 h. Organ-based activity concentration measurements indicated that AUClast tissue:blood ratios generally correlated with the anticipated presence of amyloid. Peptide uptake was observed in 4/5 clinically suspected organs, as noted in the medical record, as well as six anatomic sites generally associated with amyloidosis in this population. CONCLUSION Peptide 124I-p5+14 rapidly distributes to anatomic sites consistent with the presence of amyloid in patients with systemic AL. The dosimetry estimates established in this cohort are acceptable for whole-body PET/CT imaging. Pharmacokinetic parameters are heterogeneous and consistent with uptake of the tracer in an amyloid compartment. PET/CT imaging of 124I-p5+14 may facilitate non-invasive detection of amyloid in multiple organ systems.
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Affiliation(s)
- Jonathan S Wall
- Department of Medicine, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN, 37920, USA.
| | - Emily B Martin
- Department of Medicine, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN, 37920, USA
| | | | - Alan C Stuckey
- Department of Medicine, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN, 37920, USA
| | - Angela D Williams
- Department of Medicine, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN, 37920, USA
| | - Dustin Powell
- Department of Radiology, The University of Tennessee Graduate School of Medicine, Knoxville, TN, USA
| | - Bryan Whittle
- Department of Radiology, The University of Tennessee Graduate School of Medicine, Knoxville, TN, USA
| | - Sarah Hall
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Tyler R Lambeth
- Department of Chemistry, University of California Riverside, Riverside, CA, USA
| | - Ryan R Julian
- Department of Chemistry, University of California Riverside, Riverside, CA, USA
| | | | - Ronald H Lands
- Department of Medicine, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN, 37920, USA
| | - Stephen J Kennel
- Department of Medicine, The University of Tennessee Graduate School of Medicine, 1924 Alcoa Highway, Knoxville, TN, 37920, USA
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Martin EB, Donnell R, Richey T, Stuckey A, Kennel SJ, Wall JS. Discrete binding patterns of two heparin-reactive proteins, basic fibroblast growth factor and peptide p5R, in amyloid-laden and healthy mice. Biochem Biophys Res Commun 2021; 552:136-141. [PMID: 33744761 PMCID: PMC8035312 DOI: 10.1016/j.bbrc.2021.03.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/10/2021] [Indexed: 12/24/2022]
Abstract
Peptide p5R is a synthetic, polybasic, heparin-binding peptide that preferentially reacts with amyloid deposits in vivo and in tissue sections. Basic fibroblast growth factor (bFGF1) similarly interacts with heparin-like molecules, notably heparan sulfate proteoglycans (HSPG), in the extracellular matrix and on cell surfaces. The aim of this study was to compare the biodistribution of p5R and bFGF in healthy mice as well as those with systemic inflammation-associated amyloidosis (AA), which contains HSPG, by using SPECT/CT imaging, tissue biodistribution measurements and micro-autoradiography. Although both proteins are known to bind heparan sulfate, their biodistribution was remarkably different in the healthy and diseased animals. Imaging revealed uptake of both radiolabeled proteins in the liver, spleen, and kidneys of mice with amyloidosis; however, 125I-bFGF, but not 125I-p5R, was observed in normal tissue at sites of HSPG expression, including the hepatic and splenic sinusoids and renal glomerulae. Microautoradiography demonstrated that while p5R bound exclusively to amyloid deposits in the spleen and liver of AA mice, bFGF had a broader binding pattern. Consequently, even though bFGF and p5R both interact with heparan sulfate moieties, p5R binding was restricted to HSPG in amyloid deposits and did not bind HSPG in healthy tissues, whereas bFGF preferentially reacted with HSPG in normal tissue. The data suggest that peptide p5R selectively binds HSPG in amyloid and that the HSPG in healthy tissue, recognized by bFGF, is not targeted by the peptide.
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Affiliation(s)
- Emily B Martin
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA.
| | - Robert Donnell
- Department of Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN, USA
| | - Tina Richey
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA
| | - Alan Stuckey
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA
| | - Stephen J Kennel
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA
| | - Jonathan S Wall
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN, USA
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Tavassoly O, Safavi F, Tavassoly I. Heparin-binding Peptides as Novel Therapies to Stop SARS-CoV-2 Cellular Entry and Infection. Mol Pharmacol 2020; 98:612-619. [PMID: 32913137 DOI: 10.1124/molpharm.120.000098] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 08/27/2020] [Indexed: 01/07/2023] Open
Abstract
Heparan sulfate proteoglycans (HSPGs) are cell surface receptors that are involved in the cellular uptake of pathologic amyloid proteins and viruses, including the novel coronavirus; severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Heparin and heparan sulfate antagonize the binding of these pathogens to HSPGs and stop their cellular internalization, but the anticoagulant effect of these agents has been limiting their use in the treatment of viral infections. Heparin-binding peptides (HBPs) are suitable nonanticoagulant agents that are capable of antagonizing binding of heparin-binding pathogens to HSPGs. Here, we review and discuss the use of HBPs as viral uptake inhibitors and will address their benefits and limitations to treat viral infections. Furthermore, we will discuss a variant of these peptides that is in the clinic and can be considered as a novel therapy in coronavirus disease 2019 (COVID-19) infection. SIGNIFICANCE STATEMENT: The need to discover treatment modalities for COVID-19 is a necessity, and therapeutic interventions such as heparin-binding peptides (HBPs), which are used for other cases, can be beneficial based on their mechanisms of actions. In this paper, we have discussed the application of HBPs as viral uptake inhibitors in COVID-19 and explained possible mechanisms of actions and the therapeutic effects.
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Affiliation(s)
- Omid Tavassoly
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada (O.T.); Neuroimmunology and Neurovirology Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, Maryland (F.S.); and Mount Sinai Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, New York (I.T.)
| | - Farinaz Safavi
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada (O.T.); Neuroimmunology and Neurovirology Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, Maryland (F.S.); and Mount Sinai Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, New York (I.T.)
| | - Iman Tavassoly
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada (O.T.); Neuroimmunology and Neurovirology Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Bethesda, Maryland (F.S.); and Mount Sinai Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, New York (I.T.)
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6
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Oliveira MC, Correia JDG. Biomedical applications of radioiodinated peptides. Eur J Med Chem 2019; 179:56-77. [PMID: 31238251 DOI: 10.1016/j.ejmech.2019.06.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/04/2019] [Accepted: 06/04/2019] [Indexed: 02/08/2023]
Abstract
The overexpression of peptide receptors in certain tumors as compared to endogeneous expression levels represents the molecular basis for the design of peptide-based tools for targeted nuclear imaging and therapy. Receptor targeting with radiolabelled peptides became a very important imaging and/or therapeutic approach in nuclear medicine and oncology. A great variety of peptides has been radiolabelled with clinical relevant radionuclides, such as radiometals and radiohalogens. However, to the best of our knowledge concise and updated reviews providing information about the biomedical application of radioiodinated peptides are still missing. This review outlines the synthetic efforts in the preparation of radioiodinated peptides highlighting the importance of radioiodine in nuclear medicine, giving an overview of the most relevant radioiodination strategies that have been employed and describes relevant examples of their use in the biomedical field.
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Affiliation(s)
- Maria Cristina Oliveira
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066, Bobadela LRS, Portugal.
| | - João D G Correia
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, CTN, Estrada Nacional 10 (km 139,7), 2695-066, Bobadela LRS, Portugal.
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Nguyen VP, Palanikumar L, Kennel SJ, Alves DS, Ye Y, Wall JS, Magzoub M, Barrera FN. Mechanistic insights into the pH-dependent membrane peptide ATRAM. J Control Release 2019; 298:142-153. [PMID: 30763623 PMCID: PMC6408977 DOI: 10.1016/j.jconrel.2019.02.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/28/2019] [Accepted: 02/08/2019] [Indexed: 12/12/2022]
Abstract
pH-responsive peptides are promising therapeutic molecules that can specifically target the plasma membrane in the acidified extracellular medium that bathes cells in tumors. We designed the acidity-triggered rational membrane (ATRAM) peptide to have a pH-responsive membrane interaction. At physiological pH, ATRAM binds to the membrane surface in a largely unstructured conformation, while in acidic conditions it inserts into lipid bilayers forming a transmembrane helix. However, the molecular mechanism ATRAM uses to target and insert into tumor cells remains poorly understood. Here, we determined that ATRAM inserts into cancer cells with a preferential membrane orientation, where the C-terminus of the peptide traverses the plasma membrane and explores the cytoplasm. Using biophysical techniques, we determined that the membrane interaction of ATRAM is contingent on the concentration of the peptide. Kinetic studies showed that membrane insertion occurs in at least three steps, where only the first step was affected by the membrane density of ATRAM. These observations, combined with membrane binding and leakage data, indicate that the interaction of ATRAM with lipid membranes is dependent on its oligomerization state. SPECT/CT imaging in mice revealed that ATRAM accumulates in the blood pool, where it has a prolonged circulation time (> 4 h). Since fast peptide clearance and degradation in circulation are major problems for clinical development, we studied the mechanism ATRAM uses to remain in the blood stream. Using binding and transfer assays, we determined that ATRAM binds reversibly to human serum albumin. We propose that ATRAM uses albumin as a carrier in the blood stream to evade clearance and proteolysis before interacting with the plasma membrane of cancer cells. We also show that ATRAM is able to be deliver liposomes to cells in a pH dependent way. Our data highlight the potential of ATRAM as a specific therapeutic agent for diseases that lead to acidic tissues, including cancer.
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Affiliation(s)
- Vanessa P Nguyen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States
| | - Loganathan Palanikumar
- Biology Program, Division of Science, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Stephen J Kennel
- Departments of Medicine & Radiology, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Daiane S Alves
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States
| | - Yujie Ye
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States
| | - Jonathan S Wall
- Departments of Medicine & Radiology, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Mazin Magzoub
- Biology Program, Division of Science, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, United States.
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Wall JS, Williams A, Richey T, Stuckey A, Wooliver C, Christopher Scott J, Donnell R, Martin EB, Kennel SJ. Specific Amyloid Binding of Polybasic Peptides In Vivo Is Retained by β-Sheet Conformers but Lost in the Disrupted Coil and All D-Amino Acid Variants. Mol Imaging Biol 2018; 19:714-722. [PMID: 28229334 DOI: 10.1007/s11307-017-1063-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE The heparin-reactive, helical peptide p5 is an effective amyloid imaging agent in mice with systemic amyloidosis. Analogs of p5 with modified secondary structure characteristics exhibited altered binding to heparin, synthetic amyloid fibrils, and amyloid extracts in vitro. Herein, we further study the effects of peptide helicity and chirality on specific amyloid binding using a mouse model of systemic inflammation-associated (AA) amyloidosis. PROCEDURES Peptides with disrupted helical structure [p5(coil) and p5(Pro3)], with an extended sheet conformation [p5(sheet)] or an all-D enantiomer [p5(D)], were chemically synthesized, radioiodinated, and their biodistribution studied in WT mice as well as transgenic animals with severe systemic AA amyloidosis. Peptide binding was assessed qualitatively by using small animal single-photon emission computed tomography/x-ray computed tomography imaging and microautoradiography and quantitatively using tissue counting. RESULTS Peptides with reduced helical propensity, p5(coil) and p5(Pro3), exhibited significantly reduced binding to AA amyloid-laden organs. In contrast, peptide p5(D) was retained by non-amyloid-related ligands in the liver and kidneys of both WT and AA mice, but it also bound AA amyloid in the spleen. The p5(sheet) peptide specifically bound AA amyloid in vivo and was not retained by healthy tissues in WT animals. CONCLUSIONS Modification of amyloid-targeting peptides using D-amino acids should be performed cautiously due to the introduction of unexpected secondary pharmacologic effects. Peptides that adopt a helical structure, to align charged amino acid side chains along one face, exhibit specific reactivity with amyloid; however, polybasic peptides with a propensity for β-sheet conformation are also amyloid-reactive and may yield a novel class of amyloid-targeting agents for imaging and therapy.
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Affiliation(s)
- Jonathan S Wall
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA. .,Departments of Radiology, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA.
| | - Angela Williams
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Tina Richey
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Alan Stuckey
- Departments of Radiology, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Craig Wooliver
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - J Christopher Scott
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Robert Donnell
- Department of Pathobiology, University of Tennessee College of Veterinary Medicine, 2407 River Drive, Knoxville, TN, 37996, USA
| | - Emily B Martin
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Stephen J Kennel
- Departments of Medicine, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA.,Departments of Radiology, Graduate School of Medicine, University of Tennessee, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
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9
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Martin EB, Williams A, Richey T, Wooliver C, Stuckey A, Foster JS, Kennel SJ, Wall JS. Evaluation of the effect of D-amino acid incorporation into amyloid-reactive peptides. J Transl Med 2017; 15:247. [PMID: 29228957 PMCID: PMC5725832 DOI: 10.1186/s12967-017-1351-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/25/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Systemic amyloidoses comprise diseases characterized by the deposition of proteinaceous material known as amyloid. Currently, without performing multiple biopsies, there is no way to ascertain the extent of amyloid deposition in patients-a critical piece of information that informs prognosis and therapeutic strategies. We have developed pan-amyloid-targeting peptides for imaging amyloid and recently have adapted these for use as pre-targeting agents in conjunction with immunotherapy. Incorporation of D-amino acids in these peptides may enhance serum half-life, which is an important characteristic of effective peptide therapeutics. Herein, we assess the effects of partial incorporation of D-amino acids into the amyloidophilic peptide p5 on in vivo amyloid reactivity. METHODS Peptides, referred to as AQAp5 (d) , aqap5, and AQAp5, were radiolabeled with iodine-125 and the tissue biodistribution (% injected dose/gram) measured in healthy mice at multiple time points post-injection. Microscopic distribution of the peptides was further visualized using microautoradiography (ARG). Peptides aqap5 and AQAp5 were injected into healthy and amyloid-laden mice and evaluated by using SPECT/CT imaging at 1, 4 and 24 h post injection. RESULTS Biodistribution data and ARG revealed persistent retention of [125I]AQAp5 (d) in the liver and kidneys of healthy mice for at least 24 h. In contrast, peptides [125I]aqap5 and [125I]AQAp5 did not bind these organs and was significantly lower than [125I]AQAp5 (d) at 24 h post injection (p < 0.0001). SPECT/CT imaging of amyloid-laden mice revealed accumulation of both [125I]aqap5 and [125I]AQAp5 in amyloid-affected organs; whereas, in healthy mice, [125I]aqap5 was observed in the kidneys and liver at early time points, and free radioiodide liberated during catabolism of [125I]AQAp5 was seen in the stomach and thyroid. Autoradiography confirmed that both [125I]aqap5 and [125I]AQAp5 peptides specifically bound amyloid with no off-target binding to healthy organs. CONCLUSION Incorporation of D-amino acids in amyloid-binding regions of amyloidophilic peptides resulted in off-target binding; however, N-terminus placement retained amyloid-specificity and evasion of deiodinases. Peptide aqap5, or similar reagents, may prove useful in novel immunotherapy strategies as well as for imaging renal, gastric and pancreatic amyloidosis.
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Affiliation(s)
- Emily B Martin
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA.
| | - Angela Williams
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Tina Richey
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Craig Wooliver
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Alan Stuckey
- Department of Radiology, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - James S Foster
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Stephen J Kennel
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA.,Department of Radiology, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
| | - Jonathan S Wall
- Department of Medicine, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA.,Department of Radiology, University of Tennessee Medical Center, 1924 Alcoa Hwy, Knoxville, TN, 37920, USA
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10
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Foster JS, Williams AD, Macy S, Richey T, Stuckey A, Wooliver DC, Koul-Tiwari R, Martin EB, Kennel SJ, Wall JS. A Peptide-Fc Opsonin with Pan-Amyloid Reactivity. Front Immunol 2017; 8:1082. [PMID: 28928748 PMCID: PMC5591422 DOI: 10.3389/fimmu.2017.01082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/21/2017] [Indexed: 11/13/2022] Open
Abstract
There is a continuing need for therapeutic interventions for patients with the protein misfolding disorders that result in systemic amyloidosis. Recently, specific antibodies have been employed to treat AL amyloidosis by opsonizing tissue amyloid deposits thereby inducing cell-mediated dissolution and organ improvement. To develop a pan-amyloid therapeutic agent, we have produced an Fc-fusion product incorporating a peptide, p5, which binds many if not all forms of amyloid. This protein, designated Fcp5, expressed in mammalian cells, forms the desired bivalent dimer structure and retains pan-amyloid reactivity similar to the p5 peptide as measured by immunosorbent assays, immunohistochemistry, surface plasmon resonance, and pulldown assays using radioiodinated Fcp5. Additionally, Fcp5 was capable of opsonizing amyloid fibrils in vitro using a pH-sensitive fluorescence assay of phagocytosis. In mice,125 I-labeled Fcp5 exhibited an extended serum circulation time, relative to the p5 peptide. It specifically bound AA amyloid deposits in diseased mice, as evidenced by biodistribution and microautoradiographic methods, which coincided with an increase in active, Iba-1-positive macrophages in the liver at 48 h postinjection of Fcp5. In healthy mice, no specific tissue accumulation was observed. The data indicate that polybasic, pan-amyloid-targeting peptides, in the context of an Fc fusion, can yield amyloid reactive, opsonizing reagents that may serve as next-generation immunotherapeutics.
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Affiliation(s)
- James S Foster
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Angela D Williams
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Sallie Macy
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Tina Richey
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Alan Stuckey
- Department of Radiology, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Daniel Craig Wooliver
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Richa Koul-Tiwari
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Emily B Martin
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Stephen J Kennel
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States.,Department of Radiology, University of Tennessee Medical Center, Knoxville, TN, United States
| | - Jonathan S Wall
- Department of Medicine, University of Tennessee Medical Center, Knoxville, TN, United States.,Department of Radiology, University of Tennessee Medical Center, Knoxville, TN, United States
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11
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Cavina L, van der Born D, Klaren PHM, Feiters MC, Boerman OC, Rutjes FPJT. Design of Radioiodinated Pharmaceuticals: Structural Features Affecting Metabolic Stability towards in Vivo Deiodination. European J Org Chem 2017; 2017:3387-3414. [PMID: 28736501 PMCID: PMC5499721 DOI: 10.1002/ejoc.201601638] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Indexed: 11/09/2022]
Abstract
Radioiodinated pharmaceuticals are convenient tracers for clinical and research investigations because of the relatively long half-lives of radioactive iodine isotopes (i.e., 123I, 124I, and 131I) and the ease of their chemical insertion. Their application in radionuclide imaging and therapy may, however, be hampered by poor in vivo stability of the C-I bond. After an overview of the use of iodine in biology and nuclear medicine, we present here a survey of the catabolic pathways for iodinated xenobiotics, including their biodistribution, accumulation, and biostability. We summarize successful rational improvements in the biostability and conclude with general guidelines for the design of stable radioiodinated pharmaceuticals. It appears to be necessary to consider the whole molecule, rather than the radioiodinated fragment alone. Iodine radionuclides are generally retained in vivo on sp2 carbon atoms in iodoarenes and iodovinyl moieties, but not in iodinated heterocycles or on sp3 carbon atoms. Iodoarene substituents also have an influence, with increased in vivo deiodination in the cases of iodophenols and iodoanilines, whereas methoxylation and difluorination improve biostability.
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Affiliation(s)
- Lorenzo Cavina
- Institute of Molecules and MaterialsFaculty of ScienceRadboud UniversityHeyendaalseweg 1356525 AJ NijmegenNetherlands
- FutureChemistry Holding BV6525 ECNijmegenNetherlands
- Department of Animal Ecology & PhysiologyInstitute of Water & Wetland ResearchFaculty of ScienceRadboud UniversityPOB 90106500 GLNijmegenNetherlands
| | | | - Peter H. M. Klaren
- Department of Animal Ecology & PhysiologyInstitute of Water & Wetland ResearchFaculty of ScienceRadboud UniversityPOB 90106500 GLNijmegenNetherlands
| | - Martin C. Feiters
- Institute of Molecules and MaterialsFaculty of ScienceRadboud UniversityHeyendaalseweg 1356525 AJ NijmegenNetherlands
| | - Otto C. Boerman
- Department of Radiology & Nuclear MedicineRadboud University Medical Center6500 HBNijmegenthe Netherlands
| | - Floris P. J. T. Rutjes
- Institute of Molecules and MaterialsFaculty of ScienceRadboud UniversityHeyendaalseweg 1356525 AJ NijmegenNetherlands
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12
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Wall JS, Williams A, Wooliver C, Martin EB, Cheng X, Heidel RE, Kennel SJ. Secondary structure propensity and chirality of the amyloidophilic peptide p5 and its analogues impacts ligand binding - In vitro characterization. Biochem Biophys Rep 2016; 8:89-99. [PMID: 28345062 PMCID: PMC5363963 DOI: 10.1016/j.bbrep.2016.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/25/2016] [Accepted: 08/02/2016] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Polybasic helical peptides, such as peptide p5, bind human amyloid extracts and synthetic amyloid fibrils. When radiolabeled, peptide p5 has been shown to specifically bind amyloid in vivo thereby allowing imaging of the disease. Structural requirements for heparin and amyloid binding have been studied using analogs of p5 that modify helicity and chirality. METHODS Peptide-ligand interactions were studied using CD spectroscopy and solution-phase binding assays with radiolabeled p5 analogs. The interaction of a subset of peptides was further studied by using molecular dynamics simulations. RESULTS Disruption of the peptide helical structure reduced peptide binding to heparin and human amyloid extracts. The all-D enantiomer and the β-sheet-structured peptide bound all substrates as well as, or better than, p5. The interaction of helical and β-sheet structured peptides with Aβ fibrils was modeled and shown to involve both ionic and non-ionic interactions. CONCLUSIONS The α-helical secondary structure of peptide p5 is important for heparin and amyloid binding; however, helicity is not an absolute requirement as evidenced by the superior reactivity of a β-sheet peptide. The differential binding of the peptides with heparin and amyloid fibrils suggests that these molecular interactions are different. The all-D enantiomer of p5 and the β-sheet peptide are candidates for amyloid targeting reagents in vivo. GENERAL SIGNIFICANCE Efficient binding of polybasic peptides with amyloid is dependent on the linearity of charge spacing in the context of an α-helical secondary structure. Peptides with an α-helix or β-sheet propensity and with similar alignment of basic residues is optimal.
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Affiliation(s)
- Jonathan S. Wall
- Departments of Medicine, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
- Departments of Radiology, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
| | - Angela Williams
- Departments of Medicine, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
| | - Craig Wooliver
- Departments of Medicine, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
| | - Emily B. Martin
- Departments of Medicine, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
| | - Xiaolin Cheng
- Center for Molecular Biophysics, Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - R. Eric Heidel
- Departments of Surgery, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
| | - Stephen J. Kennel
- Departments of Medicine, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
- Departments of Radiology, University of Tennessee, Graduate School of Medicine, Knoxville, TN, USA
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13
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Zhang L, Zhang R, Yang J, Wang J, Kopeček J. Indium-based and iodine-based labeling of HPMA copolymer-epirubicin conjugates: Impact of structure on the in vivo fate. J Control Release 2016; 235:306-318. [PMID: 27266365 PMCID: PMC5061135 DOI: 10.1016/j.jconrel.2016.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/27/2016] [Accepted: 06/01/2016] [Indexed: 12/15/2022]
Abstract
Recently, we developed 2nd generation backbone degradable N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-drug conjugates which contain enzymatically cleavable sequences (GFLG) in both polymeric backbone and side-chains. This design allows using polymeric carriers with molecular weights above renal threshold without impairing their biocompatibility, thereby leading to significant improvement in therapeutic efficacy. For example, 2nd generation HPMA copolymer-epirubicin (EPI) conjugates (2P-EPI) demonstrated complete tumor regression in the treatment of mice bearing ovarian carcinoma. To obtain a better understanding of the in vivo fate of this system, we developed a dual-labeling strategy to simultaneously investigate the pharmacokinetics and biodistribution of the polymer carrier and drug EPI. First, we synthesized two different types of dual-radiolabeled conjugates, including 1) (111)In-2P-EPI-(125)I (polymeric carrier 2P was radiolabeled with (111)In and drug EPI with (125)I), and 2) (125)I-2P-EPI-(111)In (polymeric carrier 2P was radiolabeled with (125)I and drug EPI with (111)In). Then, we compared the pharmacokinetics and biodistribution of these two dual-labeled conjugates in female nude mice bearing A2780 human ovarian carcinoma. There was no significant difference in the blood circulation between polymeric carrier and payload; the carriers ((111)In-2P and (125)I-2P) showed similar retention of radioactivity in both tumor and major organs except kidney. However, compared to (111)In-labeled payload EPI, (125)I-labeled EPI showed lower radioactivity in normal organs and tumor at 48h and 144h after intravenous administration of conjugates. This may be due to different drug release rates resulting from steric hindrance to the formation of enzyme-substrate complex as indicated by cleavage experiments with lysosomal enzymes (Tritosomes). A slower release rate of EPI(DTPA)(111)In than EPI(Tyr)(125)I was observed. It may be also due to in vivo catabolism and subsequent iodine loss as literature reported. Nevertheless, tumor-to-tissue uptake ratios of both radionuclides were comparable, indicating that drug-labeling strategy does not affect the tumor targeting ability of HPMA copolymer conjugates.
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Affiliation(s)
- Libin Zhang
- Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA
| | - Rui Zhang
- Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA
| | - Jiyuan Yang
- Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA
| | - Jiawei Wang
- Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA
| | - Jindřich Kopeček
- Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
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14
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Comparative evaluation of p5+14 with SAP and peptide p5 by dual-energy SPECT imaging of mice with AA amyloidosis. Sci Rep 2016; 6:22695. [PMID: 26936002 PMCID: PMC4776142 DOI: 10.1038/srep22695] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 02/22/2016] [Indexed: 11/08/2022] Open
Abstract
Amyloidosis is a protein-misfolding disorder characterized by the extracellular deposition of amyloid, a complex matrix composed of protein fibrils, hyper-sulphated glycosaminoglycans and serum amyloid P component (SAP). Accumulation of amyloid in visceral organs results in the destruction of tissue architecture leading to organ dysfunction and failure. Early differential diagnosis and disease monitoring are critical for improving patient outcomes; thus, whole body amyloid imaging would be beneficial in this regard. Non-invasive molecular imaging of systemic amyloid is performed in Europe by using iodine-123-labelled SAP; however, this tracer is not available in the US. Therefore, we evaluated synthetic, poly-basic peptides, designated p5 and p5+14, as alternative radiotracers for detecting systemic amyloidosis. Herein, we perform a comparative effectiveness evaluation of radiolabelled peptide p5+14 with p5 and SAP, in amyloid-laden mice, using dual-energy SPECT imaging and tissue biodistribution measurements. All three radiotracers selectively bound amyloid in vivo; however, p5+14 was significantly more effective as compared to p5 in certain organs. Moreover, SAP bound principally to hepatosplenic amyloid, whereas p5+14 was broadly distributed in numerous amyloid-laden anatomic sites, including the spleen, liver, pancreas, intestines and heart. These data support clinical validation of p5+14 as an amyloid radiotracer for patients in the US.
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15
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Kennel SJ, Williams A, Stuckey A, Richey T, Wooliver C, Chazin W, Stern DA, Martin EB, Wall JS. The pattern recognition reagents RAGE VC1 and peptide p5 share common binding sites and exhibit specific reactivity with AA amyloid in mice. Amyloid 2016; 23:8-16. [PMID: 26701064 PMCID: PMC4832564 DOI: 10.3109/13506129.2015.1112782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UNLABELLED In the US, there remains a need to develop a clinical method for imaging amyloid load in patients with systemic, visceral amyloidosis. The receptor for advanced glycation end products (RAGE), which exists as a transmembrane receptor and soluble variant, is found associated with a number of amyloid deposits in man. It is unclear whether amyloid-associated RAGE is the membrane or soluble form; however, given the affinity of RAGE for amyloid, we have examined the ability of soluble RAGE VC1 to specifically localize with systemic AA amyloid in mice. We further compared the reactivity of RAGE VC1 with that of the synthetic, amyloid-reactive peptide p5. METHODS Binding of radiolabeled RAGE VC1 and p5 to synthetic amyloid fibrils was evaluated using in vitro "pulldown" assays in the presence or absence of RAGE ligands. Radioiodinated RAGE VC1 and technetium-99 m-labeled p5 were studied in mice with systemic AA amyloidosis using dual-energy SPECT/CT imaging, biodistribution and microautoradiography. RESULTS Soluble RAGE VC1 competed with radioiodinated peptide p5 for binding to rVλ6Wil, Aβ (1-40) and IAPP fibrils but not with the higher affinity peptide, p5R. Pre-incubation with AGE-BSA abrogated binding of VC1 and p5 to rVλ6Wil fibrils. Dual-energy SPECT/CT images and quantitative tissue biodistribution data showed that soluble RAGE VC1 specifically bound AA amyloid-laden organs in mice as effectively as peptide p5. Furthermore, microautoradiography confirmed that RAGE VC1 bound specifically to areas of Congo red-positive amyloid in mouse tissues but not in comparable tissues from control WT mice. CONCLUSION Soluble RAGE VC1 and peptide p5 have similar ligand binding properties and specifically localize with visceral AA amyloid deposits in mice.
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Affiliation(s)
- Stephen J Kennel
- a Department of Medicine and.,b Department of Radiology , University of Tennessee, Graduate School of Medicine , Knoxville , TN , USA
| | | | - Alan Stuckey
- b Department of Radiology , University of Tennessee, Graduate School of Medicine , Knoxville , TN , USA
| | | | | | - Walter Chazin
- c Departments of Biochemistry and Chemistry , Center for Structural Biology, Vanderbilt University , Nashville , TN , USA , and
| | - David A Stern
- d Department of Medicine , University of Tennessee School of Medicine , Memphis , TN , USA
| | | | - Jonathan S Wall
- a Department of Medicine and.,b Department of Radiology , University of Tennessee, Graduate School of Medicine , Knoxville , TN , USA
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16
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Wall JS, Martin EB, Richey T, Stuckey AC, Macy S, Wooliver C, Williams A, Foster JS, McWilliams-Koeppen P, Uberbacher E, Cheng X, Kennel SJ. Preclinical Validation of the Heparin-Reactive Peptide p5+14 as a Molecular Imaging Agent for Visceral Amyloidosis. Molecules 2015; 20:7657-82. [PMID: 25923515 PMCID: PMC4442108 DOI: 10.3390/molecules20057657] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/22/2015] [Indexed: 01/11/2023] Open
Abstract
Amyloid is a complex pathologic matrix comprised principally of paracrystalline protein fibrils and heparan sulfate proteoglycans. Systemic amyloid diseases are rare, thus, routine diagnosis is often challenging. The glycosaminoglycans ubiquitously present in amyloid deposits are biochemically and electrochemically distinct from those found in the healthy tissues due to the high degree of sulfation. We have exploited this unique property and evaluated heparin-reactive peptides, such as p5+14, as novel agents for specifically targeting and imaging amyloid. Herein, we demonstrate that radiolabeled p5+14 effectively bound murine AA amyloid in vivo by using molecular imaging. Biotinylated peptide also reacted with the major forms of human amyloid in tissue sections as evidenced immunohistochemically. Furthermore, we have demonstrated that the peptide also binds synthetic amyloid fibrils that lack glycosaminoglycans implying that the dense anionic motif present on heparin is mimicked by the amyloid protein fibril itself. These biochemical and functional data support the translation of radiolabeled peptide p5+14 for the clinical imaging of amyloid in patients.
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Affiliation(s)
- Jonathan S Wall
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
- Department of and Radiology, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Emily B Martin
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Tina Richey
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Alan C Stuckey
- Department of and Radiology, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Sallie Macy
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Craig Wooliver
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Angela Williams
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - James S Foster
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Penney McWilliams-Koeppen
- Department of and Radiology, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
| | - Ed Uberbacher
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Xiaolin Cheng
- Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Stephen J Kennel
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
- Department of and Radiology, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920, USA.
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17
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Watanabe H, Ono M, Iikuni S, Kimura H, Okamoto Y, Ihara M, Saji H. Synthesis and biological evaluation of 123I-labeled pyridyl benzoxazole derivatives: novel β-amyloid imaging probes for single-photon emission computed tomography. RSC Adv 2015. [DOI: 10.1039/c4ra10742j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The result in the present study suggested that [123I]9 may be a potential SPECT probe for imaging β-amyloid plaques in the brains of patient with Alzheimer's disease.
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Affiliation(s)
- Hiroyuki Watanabe
- Department of Patho-Functional Bioanalysis
- Graduate School of Pharmaceutical Sciences
- Kyoto University
- Kyoto 606-8501
- Japan
| | - Masahiro Ono
- Department of Patho-Functional Bioanalysis
- Graduate School of Pharmaceutical Sciences
- Kyoto University
- Kyoto 606-8501
- Japan
| | - Shimpei Iikuni
- Department of Patho-Functional Bioanalysis
- Graduate School of Pharmaceutical Sciences
- Kyoto University
- Kyoto 606-8501
- Japan
| | - Hiroyuki Kimura
- Department of Patho-Functional Bioanalysis
- Graduate School of Pharmaceutical Sciences
- Kyoto University
- Kyoto 606-8501
- Japan
| | - Yoko Okamoto
- Department of Pathology
- National Cerebral and Cardiovascular Center
- Suita
- Japan
| | - Masafumi Ihara
- Department of Stroke and Cerebrovascular Diseases
- National Cerebral and Cardiovascular Center
- Suita
- Japan
| | - Hideo Saji
- Department of Patho-Functional Bioanalysis
- Graduate School of Pharmaceutical Sciences
- Kyoto University
- Kyoto 606-8501
- Japan
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