A HSP60-targeting peptide for cell apoptosis imaging

Area of Science:

• Biomedical imaging
• Cell biology
• Molecular diagnostics

Background:

• Apoptosis is crucial in physiological and pathological processes.
• Effective apoptosis detection is vital for therapy evaluation, disease monitoring, and drug screening.
• Existing methods for apoptosis visualization require improvement in speed and directness.

Purpose of the Study:

• To develop and characterize a novel apoptosis imaging probe based on heat shock protein 60 (HSP60).
• To evaluate the probe's efficacy for in vitro and in vivo apoptosis detection.
• To elucidate the binding mechanism and apoptotic stage specificity of the novel probe.

Main Methods:

• Development of a heat shock protein 60 (HSP60)-based apoptosis imaging probe (P17).
• In vitro studies using flow cytometry to assess P17 binding to drug-induced apoptotic cells.
• In vivo fluorescent imaging of subcutaneous tumors in mice after P17 administration.
• Pull-down assays and mass spectrometry to confirm P17 specificity for HSP60.
• Double staining assays to determine P17's correlation with phosphatidylserine exposure, caspase-3 activation, and apoptotic stage.

Main Results:

• P17 effectively labeled multiple drug-induced apoptotic cells in vitro with over 10-fold higher binding to apoptotic versus viable cells.
• P17 binding intensity correlated with the level of apoptosis across six cell lines.
• In vivo imaging demonstrated P17's ability to visualize apoptosis in subcutaneous tumors.
• P17 specifically binds to HSP60 accumulated in apoptotic cells.
• P17 binding correlates with phosphatidylserine exposure and caspase-3 activation, indicating late-stage apoptosis detection.

Conclusions:

• P17 is a novel, specific, and sensitive apoptosis imaging probe targeting HSP60.
• The probe demonstrates significant potential for both in vitro and in vivo detection of apoptosis.
• P17's specificity for late-stage apoptosis suggests a role for HSP60 in this phase.
• This probe offers a promising tool for therapeutic effect evaluation, disease monitoring, and drug screening.