A fluorogenic cyclic peptide for imaging and quantification of drug-induced apoptosis
Nicole D Barth1, Ramon Subiros-Funosas1, Lorena Mendive-Tapia1
1Centre for Inflammation Research, University of Edinburgh, EH16 4TJ, Edinburgh, UK.
Abstract:
Programmed cell death or apoptosis is a central biological process that is dysregulated in many diseases, including inflammatory conditions and cancer. The detection and quantification of apoptotic cells in vivo is hampered by the need for fixatives or washing steps for non-fluorogenic reagents, and by the low levels of free calcium in diseased tissues that restrict the use of annexins. In this manuscript, we report the rational design of a highly stable fluorogenic peptide (termed Apo-15) that selectively stains apoptotic cells in vitro and in vivo in a calcium-independent manner and under wash-free conditions. Furthermore, using a combination of chemical and biophysical methods, we identify phosphatidylserine as a molecular target of Apo-15. We demonstrate that Apo-15 can be used for the quantification and imaging of drug-induced apoptosis in preclinical mouse models, thus creating opportunities for assessing the in vivo efficacy of anti-inflammatory and anti-cancer therapeutics.
Insights
Researchers developed Apo-15, a novel fluorogenic peptide for detecting apoptotic cells. This wash-free, calcium-independent method enables in vivo imaging and quantification of apoptosis in disease models.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Programmed cell death (apoptosis) is crucial in health and disease, but its in vivo detection is challenging.
- Current methods for detecting apoptotic cells often require fixatives, washing, or are limited by calcium levels in diseased tissues.
Purpose of the Study:
- To design a novel, stable fluorogenic peptide for selective and efficient detection of apoptotic cells.
- To enable wash-free, calcium-independent in vitro and in vivo imaging and quantification of apoptosis.
Main Methods:
- Rational design of a fluorogenic peptide (Apo-15).
- Chemical and biophysical methods to identify the molecular target.
- Application in preclinical mouse models for imaging drug-induced apoptosis.
Main Results:
- Apo-15 selectively stains apoptotic cells in vitro and in vivo under wash-free, calcium-independent conditions.
- Phosphatidylserine was identified as the molecular target of Apo-15.
- Successful quantification and imaging of drug-induced apoptosis in mouse models.
Conclusions:
- Apo-15 offers a robust tool for assessing apoptosis in various disease contexts.
- This method provides new opportunities for evaluating the efficacy of anti-cancer and anti-inflammatory drugs in vivo.
