Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography

The fibrillary aggregation of α-synuclein is a hallmark of Parkinson’s disease (PD) and a potential target for diagnostics and therapeutics. Although substantial effort has been devoted to the development of positron emission tomography (PET) probes for detecting α-synuclein aggregates, no clinicall...

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Main Authors: Haiyang Zhao, Tianyu Huang, Dhruva D. Dhavale, Jennifer Y. O’Shea, Zsofia Lengyel-Zhand, Dinahlee Saturnino Guarino, Jiwei Gu, Xuyi Yue, Ying-Hwey Nai, Hao Jiang, Marshall G. Lougee, Vinayak V. Pagar, Hee Jong Kim, Benjamin A. Garcia, E. James Petersson, Chester A. Mathis, Paul T. Kotzbauer, Joel S. Perlmutter, Robert H. Mach, Zhude Tu
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Language:English
Published: MDPI AG 2025-07-01
Series:Cells
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Online Access:https://www.mdpi.com/2073-4409/14/14/1108
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author Haiyang Zhao
Tianyu Huang
Dhruva D. Dhavale
Jennifer Y. O’Shea
Zsofia Lengyel-Zhand
Dinahlee Saturnino Guarino
Jiwei Gu
Xuyi Yue
Ying-Hwey Nai
Hao Jiang
Marshall G. Lougee
Vinayak V. Pagar
Hee Jong Kim
Benjamin A. Garcia
E. James Petersson
Chester A. Mathis
Paul T. Kotzbauer
Joel S. Perlmutter
Robert H. Mach
Zhude Tu
author_facet Haiyang Zhao
Tianyu Huang
Dhruva D. Dhavale
Jennifer Y. O’Shea
Zsofia Lengyel-Zhand
Dinahlee Saturnino Guarino
Jiwei Gu
Xuyi Yue
Ying-Hwey Nai
Hao Jiang
Marshall G. Lougee
Vinayak V. Pagar
Hee Jong Kim
Benjamin A. Garcia
E. James Petersson
Chester A. Mathis
Paul T. Kotzbauer
Joel S. Perlmutter
Robert H. Mach
Zhude Tu
author_sort Haiyang Zhao
collection DOAJ
description The fibrillary aggregation of α-synuclein is a hallmark of Parkinson’s disease (PD) and a potential target for diagnostics and therapeutics. Although substantial effort has been devoted to the development of positron emission tomography (PET) probes for detecting α-synuclein aggregates, no clinically suitable tracer has been reported. The design and synthesis of 43 new <i>N</i>-(6-methoxypyridin-3-yl)quinolin-2-amine derivatives and an evaluation of their α-synuclein binding affinity is reported here. Compounds <b>7f</b>, <b>7j</b>, and <b>8i</b> exhibited high affinity for α-synuclein and were selected for <sup>11</sup>C, <sup>18</sup>F, <sup>125</sup>I, or <sup>3</sup>H radiolabeling. A photoaffinity variant, <b>TZ-CLX</b>, structurally related to <b>7j</b> and <b>8i</b>, demonstrated preferential binding to the C-terminal region of α-synuclein fibrils. PET brain imaging studies using [<sup>11</sup>C]<b>7f</b>, [<sup>18</sup>F]<b>7j</b>, and [<sup>11</sup>C]<b>8i</b> in non-human primates indicated that these three α-synuclein PET tracers penetrated the blood–brain barrier. Both [<sup>11</sup>C]<b>7f</b> and [<sup>18</sup>F]<b>7j</b> showed more favorable brain washout pharmacokinetics than [<sup>11</sup>C]<b>8i</b>. In vitro binding assays showed that [<sup>125</sup>I]<b>8i</b> is a very potent α-synuclein radioligand, with K<sub>d</sub> values of 5 nM for both PD brain tissues and LBD-amplified fibrils; it is also selective for PD tissues versus AD or control tissues. These results strongly suggest that the PET probes based on the <i>N</i>-(6-methoxypyridin-3-yl)quinoline-2-amine scaffold have potential utility in detecting α-synuclein aggregates in vivo.
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spelling doaj-art-e66bddb3c171467f81bb39c33b8d0dd42025-08-20T03:58:31ZengMDPI AGCells2073-44092025-07-011414110810.3390/cells14141108Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission TomographyHaiyang Zhao0Tianyu Huang1Dhruva D. Dhavale2Jennifer Y. O’Shea3Zsofia Lengyel-Zhand4Dinahlee Saturnino Guarino5Jiwei Gu6Xuyi Yue7Ying-Hwey Nai8Hao Jiang9Marshall G. Lougee10Vinayak V. Pagar11Hee Jong Kim12Benjamin A. Garcia13E. James Petersson14Chester A. Mathis15Paul T. Kotzbauer16Joel S. Perlmutter17Robert H. Mach18Zhude Tu19Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Radiology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Neurology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Neurology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Radiology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Radiology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Radiology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Radiology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Radiology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USADepartment of Neurology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Neurology, Washington University School of Medicine, St Louis, MO 63110, USADepartment of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USADepartment of Radiology, Washington University School of Medicine, St Louis, MO 63110, USAThe fibrillary aggregation of α-synuclein is a hallmark of Parkinson’s disease (PD) and a potential target for diagnostics and therapeutics. Although substantial effort has been devoted to the development of positron emission tomography (PET) probes for detecting α-synuclein aggregates, no clinically suitable tracer has been reported. The design and synthesis of 43 new <i>N</i>-(6-methoxypyridin-3-yl)quinolin-2-amine derivatives and an evaluation of their α-synuclein binding affinity is reported here. Compounds <b>7f</b>, <b>7j</b>, and <b>8i</b> exhibited high affinity for α-synuclein and were selected for <sup>11</sup>C, <sup>18</sup>F, <sup>125</sup>I, or <sup>3</sup>H radiolabeling. A photoaffinity variant, <b>TZ-CLX</b>, structurally related to <b>7j</b> and <b>8i</b>, demonstrated preferential binding to the C-terminal region of α-synuclein fibrils. PET brain imaging studies using [<sup>11</sup>C]<b>7f</b>, [<sup>18</sup>F]<b>7j</b>, and [<sup>11</sup>C]<b>8i</b> in non-human primates indicated that these three α-synuclein PET tracers penetrated the blood–brain barrier. Both [<sup>11</sup>C]<b>7f</b> and [<sup>18</sup>F]<b>7j</b> showed more favorable brain washout pharmacokinetics than [<sup>11</sup>C]<b>8i</b>. In vitro binding assays showed that [<sup>125</sup>I]<b>8i</b> is a very potent α-synuclein radioligand, with K<sub>d</sub> values of 5 nM for both PD brain tissues and LBD-amplified fibrils; it is also selective for PD tissues versus AD or control tissues. These results strongly suggest that the PET probes based on the <i>N</i>-(6-methoxypyridin-3-yl)quinoline-2-amine scaffold have potential utility in detecting α-synuclein aggregates in vivo.https://www.mdpi.com/2073-4409/14/14/1108α-synuclein aggregatesParkinson’s diseaseradiolabelingPET imagingtracer development
spellingShingle Haiyang Zhao
Tianyu Huang
Dhruva D. Dhavale
Jennifer Y. O’Shea
Zsofia Lengyel-Zhand
Dinahlee Saturnino Guarino
Jiwei Gu
Xuyi Yue
Ying-Hwey Nai
Hao Jiang
Marshall G. Lougee
Vinayak V. Pagar
Hee Jong Kim
Benjamin A. Garcia
E. James Petersson
Chester A. Mathis
Paul T. Kotzbauer
Joel S. Perlmutter
Robert H. Mach
Zhude Tu
Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography
Cells
α-synuclein aggregates
Parkinson’s disease
radiolabeling
PET imaging
tracer development
title Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography
title_full Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography
title_fullStr Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography
title_full_unstemmed Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography
title_short Discovery of <i>N</i>-(6-Methoxypyridin-3-yl)quinoline-2-amine Derivatives for Imaging Aggregated α-Synuclein in Parkinson’s Disease with Positron Emission Tomography
title_sort discovery of i n i 6 methoxypyridin 3 yl quinoline 2 amine derivatives for imaging aggregated α synuclein in parkinson s disease with positron emission tomography
topic α-synuclein aggregates
Parkinson’s disease
radiolabeling
PET imaging
tracer development
url https://www.mdpi.com/2073-4409/14/14/1108
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