Limits...
In vivo imaging of endogenous enzyme activities using luminescent 1,2-dioxetane compounds.

Tseng JC, Kung AL - J. Biomed. Sci. (2015)

Bottom Line: In living animals, we used a similar approach to non-invasively image alkaline phosphatase activity in the peritoneal cavity.In this report, we provide proof-of-concept for CIEEL imaging of in vivo enzymatic activity.In addition, we demonstrate the use of CIEEL energy transfer for visualizing elevated alkaline phosphatase activity associated with tissue inflammation in living animals.

View Article: PubMed Central - PubMed

Affiliation: Lurie Family Imaging Center, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA. jct223@gmail.com.

ABSTRACT

Background: Here we present a non-invasive imaging method for visualizing endogenous enzyme activities in living animals. This optical imaging method is based on an energy transfer principle termed chemically initiated electron exchange luminescence (CIEEL). The light energy is provided by enzymatic activation of metastable 1,2-dioxetane substrates, whose protective groups are removed by hydrolytic enzymes such as β-galactosidase and alkaline phosphatase. In the presence of a nearby fluorescent recipient, the chemical energy within the activated substrate is then transferred via formation of a charge-transfer complex with the fluorophore, a mechanism closely related to glow stick chemistry.

Results: Efficient CIEEL energy transfer requires close proximity between the trigger enzyme and the fluorescent recipient. Using cells stained with fluorescent dialkylcarbocyanines as the energy recipients, we demonstrated CIEEL imaging of cellular β-galactosidase or alkaline phosphatase activity. In living animals, we used a similar approach to non-invasively image alkaline phosphatase activity in the peritoneal cavity.

Conclusions: In this report, we provide proof-of-concept for CIEEL imaging of in vivo enzymatic activity. In addition, we demonstrate the use of CIEEL energy transfer for visualizing elevated alkaline phosphatase activity associated with tissue inflammation in living animals.

No MeSH data available.


Spectral unmixing of the CIEEL signals from different fluorophores. a The emission profile data in Fig. 3b were spectrally unmixed using the Living Image software. A pseudocolor composite was generated where the red color indicated the relative DiR CIEEL signals and the green color indicated the relative DiD CIEEL signals. b The unmixed emission profiles of DiD and DiR CIEEL signals
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4477311&req=5

Fig4: Spectral unmixing of the CIEEL signals from different fluorophores. a The emission profile data in Fig. 3b were spectrally unmixed using the Living Image software. A pseudocolor composite was generated where the red color indicated the relative DiR CIEEL signals and the green color indicated the relative DiD CIEEL signals. b The unmixed emission profiles of DiD and DiR CIEEL signals

Mentions: By analyzing the emission profile data using the spectral unmixing function of the Living Image software of the IVIS imaging system, we identified two major emission components (Fig. 4). A composite image was generated to illustrate the sources of CIEEL signals (Fig. 4a, composite), where the green indicated the DiD emission and the red indicated the DiR emission. The two emission spectra fit nicely with the corresponding emission profiles of DiD and DiR (Fig. 4b). Interestingly, spectral unmixing makes it possible to perform multi-color energy transfer imaging on the same cells stained with multiple fluorescent dyes (DiD + DiR, Fig. 4b), a unique capability which would be useful for simultaneous investigation of multiple bio-physiological changes.Fig. 4


In vivo imaging of endogenous enzyme activities using luminescent 1,2-dioxetane compounds.

Tseng JC, Kung AL - J. Biomed. Sci. (2015)

Spectral unmixing of the CIEEL signals from different fluorophores. a The emission profile data in Fig. 3b were spectrally unmixed using the Living Image software. A pseudocolor composite was generated where the red color indicated the relative DiR CIEEL signals and the green color indicated the relative DiD CIEEL signals. b The unmixed emission profiles of DiD and DiR CIEEL signals
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4477311&req=5

Fig4: Spectral unmixing of the CIEEL signals from different fluorophores. a The emission profile data in Fig. 3b were spectrally unmixed using the Living Image software. A pseudocolor composite was generated where the red color indicated the relative DiR CIEEL signals and the green color indicated the relative DiD CIEEL signals. b The unmixed emission profiles of DiD and DiR CIEEL signals
Mentions: By analyzing the emission profile data using the spectral unmixing function of the Living Image software of the IVIS imaging system, we identified two major emission components (Fig. 4). A composite image was generated to illustrate the sources of CIEEL signals (Fig. 4a, composite), where the green indicated the DiD emission and the red indicated the DiR emission. The two emission spectra fit nicely with the corresponding emission profiles of DiD and DiR (Fig. 4b). Interestingly, spectral unmixing makes it possible to perform multi-color energy transfer imaging on the same cells stained with multiple fluorescent dyes (DiD + DiR, Fig. 4b), a unique capability which would be useful for simultaneous investigation of multiple bio-physiological changes.Fig. 4

Bottom Line: In living animals, we used a similar approach to non-invasively image alkaline phosphatase activity in the peritoneal cavity.In this report, we provide proof-of-concept for CIEEL imaging of in vivo enzymatic activity.In addition, we demonstrate the use of CIEEL energy transfer for visualizing elevated alkaline phosphatase activity associated with tissue inflammation in living animals.

View Article: PubMed Central - PubMed

Affiliation: Lurie Family Imaging Center, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA, 02215, USA. jct223@gmail.com.

ABSTRACT

Background: Here we present a non-invasive imaging method for visualizing endogenous enzyme activities in living animals. This optical imaging method is based on an energy transfer principle termed chemically initiated electron exchange luminescence (CIEEL). The light energy is provided by enzymatic activation of metastable 1,2-dioxetane substrates, whose protective groups are removed by hydrolytic enzymes such as β-galactosidase and alkaline phosphatase. In the presence of a nearby fluorescent recipient, the chemical energy within the activated substrate is then transferred via formation of a charge-transfer complex with the fluorophore, a mechanism closely related to glow stick chemistry.

Results: Efficient CIEEL energy transfer requires close proximity between the trigger enzyme and the fluorescent recipient. Using cells stained with fluorescent dialkylcarbocyanines as the energy recipients, we demonstrated CIEEL imaging of cellular β-galactosidase or alkaline phosphatase activity. In living animals, we used a similar approach to non-invasively image alkaline phosphatase activity in the peritoneal cavity.

Conclusions: In this report, we provide proof-of-concept for CIEEL imaging of in vivo enzymatic activity. In addition, we demonstrate the use of CIEEL energy transfer for visualizing elevated alkaline phosphatase activity associated with tissue inflammation in living animals.

No MeSH data available.