Characterization of Large Extracellular Vesicles Released by Apoptotic and Pyroptotic Cells.

Area of Science:

• Cell Biology
• Molecular Biology
• Immunology

Background:

• Extracellular vesicles (EVs) are crucial for intercellular communication and cellular homeostasis.
• Small EVs are well-characterized, but the molecular signatures of large EVs, especially during cell death, remain largely undefined.
• Regulated cell death pathways generate distinct EV populations with potential roles in disease and therapy.

Purpose of the Study:

• To characterize the molecular signatures of large EVs released during apoptosis and pyroptosis.
• To compare the protein cargo of large EVs from healthy cells versus cells undergoing regulated cell death.
• To identify potential biomarkers for large EVs derived from dying cells.

Main Methods:

• Induction of apoptosis (staurosporine) and pyroptosis (LPS/nigericin) in human monocytic cell lines (THP-1, U937).
• Inhibition of apoptosis (pan-caspase inhibitor) and pyroptosis (NLRP3 inhibitor).
• Characterization of large EVs using Annexin V binding, CD9 expression, and proteomic profiling.

Main Results:

• Both apoptosis and pyroptosis significantly increased large EV release.
• Apoptotic and pyroptotic large EVs exhibited altered Annexin V binding and CD9 expression compared to controls.
• Distinct proteomic profiles were observed: pyroptotic EVs contained RNA-binding and chromatin-associated proteins (DAMPs/alarmins), while apoptotic EVs carried dsDNA and active caspase-3/7.

Conclusions:

• Large EVs released during apoptosis and pyroptosis possess unique molecular cargo.
• This study identifies candidate markers for large EVs originating from dying cells.
• Findings enhance understanding of EV roles in regulated cell death and potential biomarker discovery.