A synthetic luciferin improves in vivo bioluminescence imaging of gene expression in cardiovascular brain regions.
Bioluminescence imaging is an effective tool for in vivo investigation of molecular processes. We have demonstrated the applicability of bioluminescence imaging to spatiotemporally monitor gene expression in cardioregulatory brain nuclei during the development of cardiovascular disease, via incorporation of firefly luciferase into living animals, combined with exogenous d-luciferin substrate administration. Nevertheless, d-luciferin uptake into the brain tissue is low, which decreases the sensitivity of bioluminescence detection, particularly when considering small changes in gene expression in tiny central areas. Here, we tested the hypothesis that a synthetic luciferin, cyclic alkylaminoluciferin (CycLuc1), would be superior to d-luciferin for in vivo bioluminescence imaging in cardiovascular brain regions. Male C57B1/6 mice underwent targeted delivery of an adenovirus encoding the luciferase gene downstream of the CMV promoter to the subfornical organ (SFO) or paraventricular nucleus of hypothalamus (PVN), two crucial cardioregulatory neural regions. While bioluminescent signals could be obtained following d-luciferin injection (150 mg/kg), CycLuc1 administration resulted in a three- to fourfold greater bioluminescent emission from the SFO and PVN, at 10- to 20-fold lower substrate concentrations (7.5-15 mg/kg). This CycLuc1-mediated enhancement in bioluminescent emission was evident early following substrate administration (i.e., 6-10 min) and persisted for up to 1 h. When the exposure time was reduced from 60 s to 1,500 ms, minimal signal in the PVN was detectable with d-luciferin, whereas bioluminescent images could be reliably captured with CycLuc1. These findings demonstrate that bioluminescent imaging with the synthetic luciferin CycLuc1 provides an improved physiological genomics tool to investigate molecular events in discrete cardioregulatory brain nuclei.
Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia.
Hayk
H
Simonyan
Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia.
Chansol
C
Hurr
Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia colinyoung@gwu.edu.
Colin N
CN
Young
D000256:Adenoviridae / Q000378:metabolism; D000818:Animals; D052160:Benzothiazoles / Q000494:pharmacology*; D002319:Cardiovascular System / Q000187:drug effects* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D008156:Luciferases / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects; D013356:Subfornical Organ / Q000187:drug effects* / Q000378:metabolism
D052160:Benzothiazoles; C532924:D-luciferin; D008156:Luciferases
CycLuc1; cardiovascular disease; d-luciferin; hypothalamus; subfornical organ