title: MRI reveals differential effects of amphetamine exposure on neuroglia in vivo.
abstract: How amphetamine affects the neuroglia in living brains is not well understood. In an effort to elucidate this effect, we investigated neuroglia in response to amphetamine exposure using antisense (AS) or sense (S) phosphorothioate-modified oligodeoxynucleotide (sODN) sequences that correspond to glial fibrillary acidic protein (GFAP) mRNA (AS-gfap or S-gfap, respectively) expression. The control is a random-sequence sODN (Ran). Using cyanine 5.5-superparamagnetic iron oxide nanoparticle (Cy5.5-SPION) labeling and fluorescent microscopy, we demonstrated that living neural progenitor cells (PC-12.1), as well as the cells in fresh brain slices and intact brains of male C57BL6 mice, exhibited universal uptake of all of the sODNs but rapidly excluded all sODN-Ran and most S-gfap. Moreover, transmission electron microscopy revealed electron-dense nanoparticles only in the neuroglia of normal or transgenic mice [B6;DBA-Tg(Fos-tTA, Fos-EGFP*)1MmayTg(tetO-lacZ,tTA*)1Mmay/J] that had been administered AS-gfap or Cy5.5-SPION-gfap. Subtraction R2* maps from mice with acute and chronic amphetamine exposure demonstrated, validated by postmortem immunohistochemistry, a reduction in striatal neuroglia, with gliogenesis in the subventricular zone and the somatosensory cortex in vivo. The sensitivity of our unique gene transcript targeted MRI was illustrated by a positive linear correlation (r(2)=1.0) between in vivo MRI signal changes and GFAP mRNA copy numbers determined by ex vivo quantitative RT-PCR. The study provides direct evidence for targeting neuroglia by antisense DNA-based SPION-gfap that enables in vivo MRI of inaccessible tissue with PCR sensitivity. The results enable us to conclude that amphetamine induces toxicity to neuroglia in vivo, which may cause remodeling or reconnectivity of neuroglia.
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: Christina H
authors.initials: CH
authors.lastname: Liu
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Yang
authors.forename: Jia Q
authors.initials: JQ
authors.lastname: Ren
authors.forename: Charng-Ming
authors.initials: CM
authors.lastname: Liu
authors.forename: Zerong
authors.initials: Z
authors.lastname: You
authors.forename: Philip K
authors.initials: PK
authors.lastname: Liu
mesh_terms: D000661:Amphetamine / Q000633:toxicity*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002232:Carbocyanines / Q000008:administration & dosage; D016503:Drug Delivery Systems; D005904:Glial Fibrillary Acidic Protein; D013287:Illicit Drugs / Q000633:toxicity; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles / Q000008:administration & dosage; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D055495:Neurogenesis / Q000187:drug effects; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D020319:Oligodeoxyribonucleotides, Antisense / Q000008:administration & dosage / Q000235:genetics / Q000493:pharmacokinetics; D016716:PC12 Cells; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats
chemical_list: C098793:CY5.5 cyanine dye; D002232:Carbocyanines; D005904:Glial Fibrillary Acidic Protein; D013287:Illicit Drugs; D058185:Magnetite Nanoparticles; D009419:Nerve Tissue Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; C528900:glial fibrillary astrocytic protein, mouse; D000661:Amphetamine