Influence of bioluminescence imaging dynamics by D-luciferin uptake and efflux mechanisms.
Bioluminescence imaging (BLI) detects light generated by luciferase-mediated oxidation of substrate and is used widely for evaluating transgene expression in cell-based assays and in vivo in relevant preclinical models. The most commonly used luciferase for in vivo applications is firefly luciferase (fLuc), for which D-luciferin serves as the substrate. We demonstrated previously that the expression of the ABCG2 efflux transporter can significantly reduce BLI signal output and that HhAntag-691 can inhibit the efflux of D-luciferin, thereby enhancing BLI signal. Here we show that an HhAntag-691-sensitive uptake mechanism facilitates the intracellular concentration of D-luciferin and that the BLI dynamics of different cell lines are coregulated by this uptake mechanism in conjunction with ABCG2-mediated efflux. After administration of D-luciferin, the HhAntag-691-sensitive uptake mechanism generates a rapid increase in BLI signal that decreases over time, whereas ABCG2-mediated efflux stably reduces signal output. We implicate SLC22A4 (OCTN1), a member of the organic cation/zwitterion uptake transporter family, as one potential mediator of the HhAntag-691-sensitive D-luciferin uptake. These findings provide insight into mechanisms that contribute to the cellular uptake kinetics and in vivo biodistribution of D-luciferin.
Russell H. Morgan Department of Radiology and Department of Neurology, Johns Hopkins Medical School, Baltimore, MD, USA.
Yimao
Y
Zhang
Mrudula
M
Pullambhatla
John
J
Laterra
Martin G
MG
Pomper
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D052160:Benzothiazoles / Q000493:pharmacokinetics*; D045744:Cell Line, Tumor; D017931:DNA Primers; D004285:Dogs; D006801:Humans; D049449:Luminescence; D008297:Male; D009363:Neoplasm Proteins / Q000378:metabolism; D061848:Optical Imaging; D027701:Organic Cation Transport Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D027981:Symporters
C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D052160:Benzothiazoles; C532924:D-luciferin; D017931:DNA Primers; D009363:Neoplasm Proteins; D027701:Organic Cation Transport Proteins; C109807:SLC22A4 protein, human; D027981:Symporters