title: Dual reporter gene imaging for tracking macrophage migration using the human sodium iodide symporter and an enhanced firefly luciferase in a murine inflammation model.
abstract: OBJECTIVE
  The purpose of this study is to visualize the migration of reporter macrophages expressing both the human sodium iodide symporter (hNIS) and enhanced firefly luciferase (effluc) gene in mice with chemically induced inflammation.
  
  
  METHODS
  A macrophage cell line expressing both hNIS and effluc genes (Raw264.7/hNIS-effluc, herein referred to as a Raw264.7/NF) was established by cotransduction of two genes into a murine macrophage cell line (Raw264.7), and cell proliferation and phagocytic activity were compared between parental Raw264.7 and Raw264.7/NF cells. Both serial bioluminescence imaging (BLI) and small animal positron emission tomography (PET) imaging with I-124 were performed in inflammation-induced mice at various time points after intravenous injection of either Raw264.7 or Raw264.7/NF cells.
  
  
  RESULTS
  There was no significant difference in cellular proliferation and phagocytic activity between parental Raw264.7 and Raw264.7/NF cells. Early distribution of Raw264.7/NF cells was successfully visualized in the lung and spleen by BLI, but not by I-124 PET imaging. BLI signals, but not PET signals, were observed from the inflammation site at day 4 after the injection of Raw264.7/NF cells, and the signal intensity gradually increased until day 8. In contrast, focal uptake of I-124 was first detected at the site of inflammation at postinjection day 8, and signal intensity from the inflamed lesion was highest at that time point. While visualization of the inflamed lesion was possible by both BLI and PET imaging until day 14, it was only possible by BLI until day 21 after injection.
  
  
  CONCLUSIONS
  Tracking of macrophage migration toward inflammation foci was successfully achieved in vivo from early time points by dual reporter gene imaging with a combination of nuclear and optical reporters. Multimodal reporter imaging of macrophages might successfully overcome the limitations of single reporter gene imaging in preclinical models of inflammation.
authors.affiliation: Department of Nuclear Medicine, School of Medicine, Kyungpook National University, 50 Samduk 2-ga, Daegu, 700-721, Republic of Korea, howonlee1234@gmail.com.
authors.forename: Ho Won
authors.initials: HW
authors.lastname: Lee
authors.forename: Yong Hyun
authors.initials: YH
authors.lastname: Jeon
authors.forename: Mi-Hye
authors.initials: MH
authors.lastname: Hwang
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Tae-in
authors.initials: TI
authors.lastname: Park
authors.forename: Jeoung-Hee
authors.initials: JH
authors.lastname: Ha
authors.forename: Sang-Woo
authors.initials: SW
authors.lastname: Lee
authors.forename: Byeong-Cheol
authors.initials: BC
authors.lastname: Ahn
authors.forename: Jaetae
authors.initials: J
authors.lastname: Lee
mesh_terms: D000818:Animals; D002460:Cell Line; D002465:Cell Movement; D058948:Cell Tracking / Q000379:methods*; D005260:Female; D017930:Genes, Reporter / Q000235:genetics; D007150:Immunohistochemistry; D007457:Iodine Radioisotopes / Q000737:chemistry / Q000493:pharmacokinetics; D049409:Luciferases, Firefly / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D061848:Optical Imaging / Q000379:methods*; D010587:Phagocytosis; D049268:Positron-Emission Tomography / Q000379:methods*; D027981:Symporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014018:Tissue Distribution; D014162:Transfection; D000099209:Sodium-Iodide Symporters
chemical_list: D007457:Iodine Radioisotopes; D049409:Luciferases, Firefly; D027981:Symporters; D000099209:Sodium-Iodide Symporters