Open AccessAntisense imaging of gene expression in the brain in vivo
Author(s) -
Ningya Shi,
Rubén J. Boado,
William M. Pardridge
Publication year - 2000
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.250332397
Subject(s) - gene expression , in vivo , biology , gene , computational biology , microbiology and biotechnology , genetics
Antisense radiopharmaceuticals could be used to image gene expression in the brainin vivo , should these polar molecules be made transportable through the blood–brain barrier. The present studies describe an antisense imaging agent comprised of an iodinated peptide nucleic acid (PNA) conjugated to a monoclonal antibody to the rat transferrin receptor by using avidin–biotin technology. The PNA was a 16-mer antisense to the sequence around the methionine initiation codon of the luciferase mRNA. C6 rat glioma cells were permanently transfected with a luciferase expression plasmid, and C6 experimental brain tumors were developed in adult rats. The expression of the luciferase transgene in the tumorsin vivo was confirmed by measurement of luciferase enzyme activity in the tumor extract. The [125 I]PNA conjugate was injected intravenously in anesthetized animals with brain tumors and killed 2 h later for frozen sectioning of brain and film autoradiography. No image of the luciferase gene expression was obtained after the administration of either the unconjugated antiluciferase PNA or a PNA conjugate that was antisense to the mRNA of a viral transcript. In contrast, tumors were imaged in all rats administered the [125 I]PNA that was antisense to the luciferase sequence and was conjugated to the targeting antibody. In conclusion, these studies demonstrate gene expression in the brainin vivo can be imaged with antisense radiopharmaceuticals that are conjugated to a brain drug-targeting system.