title: Multimodal Imaging for DREADD-Expressing Neurons in Living Brain and Their Application to Implantation of iPSC-Derived Neural Progenitors.
abstract: Chemogenetic manipulation of neuronal activities has been enabled by a designer receptor (designer receptor exclusively activated by designer drugs, DREADD) that is activated exclusively by clozapine-N-oxide (CNO). Here, we applied CNO as a functional reporter probe to positron emission tomography (PET) of DREADD in living brains. Mutant human M4 DREADD (hM4Di) expressed in transgenic (Tg) mouse neurons was visualized by PET with microdose [11C]CNO. Deactivation of DREADD-expressing neurons in these mice by nonradioactive CNO at a pharmacological dose could also be captured by arterial spin labeling MRI (ASL-MRI). Neural progenitors derived from hM4Di Tg-induced pluripotent stem cells were then implanted into WT mouse brains and neuronal differentiation of the grafts could be imaged by [11C]CNO-PET. Finally, ASL-MRI captured chemogenetic functional manipulation of the graft neurons. Our data provide the first demonstration of multimodal molecular/functional imaging of cells expressing a functional gene reporter in the brain, which would be translatable to humans for therapeutic gene transfers and cell replacements.
  
  
  
  The present work provides the first successful demonstration of in vivo positron emission tomographic (PET) visualization of a chemogenetic designer receptor (designer receptor exclusively activated by designer drugs, DREADD) expressed in living brains. This technology has been applied to longitudinal PET reporter imaging of neuronal grafts differentiated from induced pluripotent stem cells. Differentiated from currently used reporter genes for neuroimaging, DREADD has also been available for functional manipulation of target cells, which could be visualized by functional magnetic resonance imaging (fMRI) in a real-time manner. Multimodal imaging with PET/fMRI enables the visualization of the differentiation of iPSC-derived neural progenitors into mature neurons and DREADD-mediated functional manipulation along the time course of the graft and is accordingly capable of fortifying the utility of stem cells in cell replacement therapies.
authors.affiliation: Department of Functional Brain Imaging Research.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Bin
authors.identifier: 0000-0002-9672-6441
authors.initials: B
authors.lastname: Ji
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaneko
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Takafumi
authors.identifier: 0000-0003-4305-0174
authors.initials: T
authors.lastname: Minamimoto
authors.affiliation: Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Kyoto 606-8507, Japan.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Haruhisa
authors.identifier: 0000-0003-4736-9537
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Kyoto 606-8507, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: Department of Radiopharmaceuticals Development.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Kumata
authors.affiliation: Department of Radiopharmaceuticals Development.
authors.forename: Ming-Rong
authors.initials: MR
authors.lastname: Zhang
authors.affiliation: Department of Molecular Imaging and Theranostics, and.
authors.forename: Ichio
authors.identifier: 0000-0002-4429-5053
authors.initials: I
authors.lastname: Aoki
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Chie
authors.identifier: 0000-0002-3222-7125
authors.initials: C
authors.lastname: Seki
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Maiko
authors.initials: M
authors.lastname: Ono
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Masaki
authors.initials: M
authors.lastname: Tokunaga
authors.affiliation: Laboratory of Animal and Genome Science Section, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tsukamoto
authors.affiliation: Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Kyoto 606-8507, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Tanabe
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Ryong-Moon
authors.initials: RM
authors.lastname: Shin
authors.affiliation: Department of Functional Brain Imaging Research.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Minamihisamatsu
authors.affiliation: Laboratory of Animal and Genome Science Section, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263-8555, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Kito
authors.affiliation: Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892, and.
authors.forename: Barry J
authors.identifier: 0000-0002-8234-1540
authors.initials: BJ
authors.lastname: Richmond
authors.affiliation: Department of Functional Brain Imaging Research.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Suhara
authors.affiliation: Department of Functional Brain Imaging Research, mhiguchi@nirs.go.jp.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Makoto
authors.identifier: 0000-0002-3934-5810
authors.initials: M
authors.lastname: Higuchi
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology* / Q000000981:diagnostic imaging / Q000378:metabolism; D002478:Cells, Cultured; D017930:Genes, Reporter; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000637:transplantation; D051379:Mice; D008822:Mice, Transgenic; D064847:Multimodal Imaging / Q000379:methods*; D058953:Neural Stem Cells / Q000166:cytology / Q000637:transplantation*; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033581:Stem Cell Transplantation / Q000379:methods
keywords: cell replacement therapy; clozapine-N-oxide (CNO); designer receptor exclusively activated by designer drugs (DREADD); induced pluripotent stem cell (iPSC); positron emission tomography (PET)