title: Secreted luciferase for in vivo evaluation of systemic protein delivery in mice.
abstract: A naturally secreted Gaussia luciferase (Gluc) has been utilized as a reporter for bioluminescence imaging (BLI) evaluation. However, the potential application of Gluc for in vivo monitoring of systemic protein delivery, as well as its natural biodistribution, has not been studied. To examine Gluc secretion and uptake profile, we injected Gluc-encoding plasmids into mice by hydrodynamic tail-vein injection. Whole-body BLI showed that imaging quantification obtained at pawpad was directly correlated to blood Gluc activities. When gene expression was restricted to the liver by the use of a hepatic promoter, in vivo Gluc biodistribution analysis revealed the kidney/bladder, stomach/intestine, and lung as the major uptake organs. Three-dimensional BLI identified liver/stomach and lung as the main internal luminescent sources, demonstrating the feasibility of detecting major uptake organs in live animals by 3D BLI with high-background signals in circulation. Notably, Gluc levels in capillary-depleted brain samples from Gluc-injected mice were comparable to controls, suggesting that Gluc may not cross the blood-brain barrier. Gluc uptake kinetics and intracellular half-life were assessed in various types of cell lines, implicating the involvement of non-specific pinocytosis. These results suggest that Gluc-based system may provide a useful tool for in vivo evaluation of protein/agent biodistribution following systemic delivery.
authors.affiliation: Molecular and Cell Therapy Program, Division of Experimental Hematology & Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Salim S
authors.initials: SS
authors.lastname: El-Amouri
authors.forename: Phuong
authors.initials: P
authors.lastname: Cao
authors.forename: Carol
authors.initials: C
authors.lastname: Miao
authors.forename: Dao
authors.initials: D
authors.lastname: Pan
mesh_terms: D000818:Animals; D001692:Biological Transport; D001812:Blood-Brain Barrier / Q000378:metabolism; D002460:Cell Line; D033342:Copepoda / Q000201:enzymology; D015870:Gene Expression; D057809:HEK293 Cells; D006207:Half-Life; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism* / Q000493:pharmacokinetics*; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D041681:NIH 3T3 Cells; D010873:Pinocytosis; D014018:Tissue Distribution; D014161:Transduction, Genetic; D019076:Transgenes; D051598:Whole Body Imaging
chemical_list: D008156:Luciferases