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Brašić JR, Goodman JA, Nandi A, Russell DS, Jennings D, Barret O, Martin SD, Slifer K, Sedlak T, Mathur AK, Seibyl JP, Berry-Kravis EM, Wong DF, Budimirovic DB. Fragile X Mental Retardation Protein and Cerebral Expression of Metabotropic Glutamate Receptor Subtype 5 in Men with Fragile X Syndrome: A Pilot Study. Brain Sci 2022; 12:314. [PMID: 35326270 PMCID: PMC8946825 DOI: 10.3390/brainsci12030314] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/26/2022] [Accepted: 02/09/2022] [Indexed: 02/04/2023] Open
Abstract
Multiple lines of evidence suggest that a deficiency of Fragile X Mental Retardation Protein (FMRP) mediates dysfunction of the metabotropic glutamate receptor subtype 5 (mGluR5) in the pathogenesis of fragile X syndrome (FXS), the most commonly known single-gene cause of inherited intellectual disability (ID) and autism spectrum disorder (ASD). Nevertheless, animal and human studies regarding the link between FMRP and mGluR5 expression provide inconsistent or conflicting findings about the nature of those relationships. Since multiple clinical trials of glutamatergic agents in humans with FXS did not demonstrate the amelioration of the behavioral phenotype observed in animal models of FXS, we sought measure if mGluR5 expression is increased in men with FXS to form the basis for improved clinical trials. Unexpectedly marked reductions in mGluR5 expression were observed in cortical and subcortical regions in men with FXS. Reduced mGluR5 expression throughout the living brains of men with FXS provides a clue to examine FMRP and mGluR5 expression in FXS. In order to develop the findings of our previous study and to strengthen the objective tools for future clinical trials of glutamatergic agents in FXS, we sought to assess the possible value of measuring both FMRP levels and mGluR5 expression in men with FXS. We aimed to show the value of measurement of FMRP levels and mGluR5 expression for the diagnosis and treatment of individuals with FXS and related conditions. We administered 3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile ([18F]FPEB), a specific mGluR5 radioligand for quantitative measurements of the density and the distribution of mGluR5s, to six men with the full mutation (FM) of FXS and to one man with allele size mosaicism for FXS (FXS-M). Utilizing the seven cortical and subcortical regions affected in neurodegenerative disorders as indicator variables, adjusted linear regression of mGluR5 expression and FMRP showed that mGluR5 expression was significantly reduced in the occipital cortex and the thalamus relative to baseline (anterior cingulate cortex) if FMRP levels are held constant (F(7,47) = 6.84, p < 0.001).These findings indicate the usefulness of cerebral mGluR5 expression measured by PET with [18F]FPEB and FMRP values in men with FXS and related conditions for assessments in community facilities within a hundred-mile radius of a production center with a cyclotron. These initial results of this pilot study advance our previous study regarding the measurement of mGluR5 expression by combining both FMRP levels and mGluR5 expression as tools for meaningful clinical trials of glutamatergic agents for men with FXS. We confirm the feasibility of this protocol as a valuable tool to measure FMRP levels and mGluR5 expression in clinical trials of individuals with FXS and related conditions and to provide the foundations to apply precision medicine to tailor treatment plans to the specific needs of individuals with FXS and related conditions.
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Affiliation(s)
- James Robert Brašić
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (S.D.M.); (T.S.); (A.K.M.); (D.F.W.)
| | - Jack Alexander Goodman
- Frank H. Netter MD School of Medicine, Quinnipiac University, North Haven, CT 06473, USA;
| | - Ayon Nandi
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (S.D.M.); (T.S.); (A.K.M.); (D.F.W.)
| | - David S. Russell
- Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Invicro, New Haven, CT 06510, USA
| | - Danna Jennings
- Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Invicro, New Haven, CT 06510, USA
- Denali Therapeutics, Inc., South San Francisco, CA 94080, USA
| | - Olivier Barret
- Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Invicro, New Haven, CT 06510, USA
- Laboratoire des Maladies Neurodégénératives, Molecular Imaging Research Center (MIRCen), Institut de Biologie François Jacob, Centre National de la Recherche Scientifique (CNRS), Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA), Université Paris-Saclay, CEDEX, 92265 Fontenay-aux-Roses, France
| | - Samuel D. Martin
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (S.D.M.); (T.S.); (A.K.M.); (D.F.W.)
- Department of Neuroscience, Zanvyl Krieger School of Arts and Sciences, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Keith Slifer
- Department of Psychiatry and Behavioral Sciences-Child Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
- Department of Behavioral Psychology, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Thomas Sedlak
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (S.D.M.); (T.S.); (A.K.M.); (D.F.W.)
- Department of Psychiatry and Behavioral Sciences-General Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Anil Kumar Mathur
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (S.D.M.); (T.S.); (A.K.M.); (D.F.W.)
| | - John P. Seibyl
- Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Invicro, New Haven, CT 06510, USA
| | - Elizabeth M. Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, and Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA;
| | - Dean F. Wong
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (S.D.M.); (T.S.); (A.K.M.); (D.F.W.)
- Laboratory of Central Nervous System (CNS) Neuropsychopharmacology and Multimodal, Imaging (CNAMI), Mallinckrodt Institute of Radiology, Washington University, Saint Louis, MO 63110, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry and Behavioral Sciences-Child Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
- Department of Psychiatry, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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Mody M, Petibon Y, Han P, Kuruppu D, Ma C, Yokell D, Neelamegam R, Normandin MD, Fakhri GE, Brownell AL. In vivo imaging of mGlu5 receptor expression in humans with Fragile X Syndrome towards development of a potential biomarker. Sci Rep 2021; 11:15897. [PMID: 34354107 PMCID: PMC8342610 DOI: 10.1038/s41598-021-94967-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/16/2021] [Indexed: 11/21/2022] Open
Abstract
Fragile X Syndrome (FXS) is a neurodevelopmental disorder caused by silencing of the Fragile X Mental Retardation (FMR1) gene. The resulting loss of Fragile X Mental Retardation Protein (FMRP) leads to excessive glutamate signaling via metabotropic glutamate subtype 5 receptors (mGluR5) which has been implicated in the pathogenesis of the disorder. In the present study we used the radioligand 3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile ([18F]FPEB) in simultaneous PET-MR imaging of males with FXS and age- and gender-matched controls to assess the availability of mGlu5 receptors in relevant brain areas. Patients with FXS showed lower [18F]FPEB binding potential (p < 0.01), reflecting reduced mGluR5 availability, than the healthy controls throughout the brain, with significant group differences in insula, anterior cingulate, parahippocampal, inferior temporal and olfactory cortices, regions associated with deficits in inhibition, memory, and visuospatial processes characteristic of the disorder. The results are among the first to provide in vivo evidence of decreased availability of mGluR5 in the brain in individuals with FXS than in healthy controls. The consistent results across the subjects, despite the tremendous challenges with neuroimaging this population, highlight the robustness of the protocol and support for its use in drug occupancy studies; extending our radiotracer development and application efforts from mice to humans.
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Affiliation(s)
- Maria Mody
- Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA.
| | - Yoann Petibon
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Paul Han
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Darshini Kuruppu
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Chao Ma
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Daniel Yokell
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Ramesh Neelamegam
- Department of Radiology, University of Texas Health Science at San Antonio, San Antonio, TX, 78229, USA
| | - Marc D Normandin
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
| | - Anna-Liisa Brownell
- Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02129, USA
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Brašić JR, Nandi A, Russell DS, Jennings D, Barret O, Mathur A, Slifer K, Sedlak T, Martin SD, Brinson Z, Vyas P, Seibyl JP, Berry-Kravis EM, Wong DF, Budimirovic DB. Reduced Expression of Cerebral Metabotropic Glutamate Receptor Subtype 5 in Men with Fragile X Syndrome. Brain Sci 2020; 10:E899. [PMID: 33255214 PMCID: PMC7760509 DOI: 10.3390/brainsci10120899] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/07/2020] [Accepted: 11/14/2020] [Indexed: 12/28/2022] Open
Abstract
Glutamatergic receptor expression is mostly unknown in adults with fragile X syndrome (FXS). Favorable behavioral effects of negative allosteric modulators (NAMs) of the metabotropic glutamate receptor subtype 5 (mGluR5) in fmr1 knockout (KO) mouse models have not been confirmed in humans with FXS. Measurement of cerebral mGluR5 expression in humans with FXS exposed to NAMs might help in that effort. We used positron emission tomography (PET) to measure the mGluR5 density as a proxy of mGluR5 expression in cortical and subcortical brain regions to confirm target engagement of NAMs for mGluR5s. The density and the distribution of mGluR5 were measured in two independent samples of men with FXS (N = 9) and typical development (TD) (N = 8). We showed the feasibility of this complex study including MRI and PET, meaning that this challenging protocol can be accomplished in men with FXS with an adequate preparation. Analysis of variance of estimated mGluR5 expression showed that mGluR5 expression was significantly reduced in cortical and subcortical regions of men with FXS in contrast to age-matched men with TD.
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Affiliation(s)
- James R. Brašić
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
| | - Ayon Nandi
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
| | - David S. Russell
- Clinical Research, Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Research Clinic, Invicro LLC, New Haven, CT 06510, USA
| | - Danna Jennings
- Clinical Research, Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Research Clinic, Invicro LLC, New Haven, CT 06510, USA
- Denali Therapeutics, Inc., South San Francisco, CA 94080, USA
| | - Olivier Barret
- Clinical Research, Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
| | - Anil Mathur
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
| | - Keith Slifer
- Department of Psychiatry and Behavioral Sciences-Child Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
- Department of Behavioral Psychology, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Thomas Sedlak
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
- Department of Psychiatry and Behavioral Sciences-General Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Samuel D. Martin
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
- Department of Neuroscience, Zanvyl Krieger School of Arts and Sciences, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Zabecca Brinson
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
| | - Pankhuri Vyas
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
| | - John P. Seibyl
- Clinical Research, Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA; (D.S.R.); (D.J.); (O.B.); (J.P.S.)
- Research Clinic, Invicro LLC, New Haven, CT 06510, USA
| | - Elizabeth M. Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, and Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA;
| | - Dean F. Wong
- Section of High Resolution Brain Positron Emission Tomography Imaging, Division of Nuclear Medicine and Molecular Imaging, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (A.N.); (A.M.); (T.S.); (S.D.M.); (Z.B.); (P.V.); (D.F.W.)
- Precision Radio-Theranostics Translational Laboratories, Mallinckrodt Institute of Radiology, School of Medicine, Washington University, Saint Louis, MO 63110, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry and Behavioral Sciences-Child Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA;
- Departments of Psychiatry and Neurogenetics, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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