Optimized culture methods for isolating small extracellular vesicles derived from human induced pluripotent stem...

Area of Science:

• Stem cell biology
• Extracellular vesicle research
• Biotechnology

Background:

• Stem cell-derived extracellular vesicles (sEVs) show therapeutic potential.
• Optimizing sEV production is crucial for clinical applications.
• Human induced pluripotent stem cells (hiPSCs) are a promising source for sEVs.

Purpose of the Study:

• To optimize culture conditions for high-quality sEV production from hiPSCs.
• To determine optimal extracellular vesicle-depleted knockout serum replacement (ED-KSR) concentration.
• To evaluate the impact of supernatant collection duration on sEV characteristics and hiPSC viability.

Main Methods:

• hiPSCs were cultured in varying ED-KSR concentrations (0-20%) in EVs-PM.
• Supernatants were collected continuously for up to 5 days.
• sEVs were isolated and characterized for size, morphology, and marker expression (CD63, TSG101, HSP70).
• hiPSC pluripotency markers (SSEA4, TRA-1-60) and viability were assessed.
• HepG2 cells were used to evaluate sEV uptake and proliferation assays.

Main Results:

• 0.5% ED-KSR was identified as the optimal concentration, supporting hiPSC viability.
• Continuous supernatant collection for 5 days did not significantly impact hiPSC survival.
• hiPSCs maintained some pluripotent markers after 5 days of collection.
• Isolated sEVs exhibited consistent characteristics (50-200 nm, double-layered, oval/round, positive for CD63, TSG101, HSP70) across collection days.
• sEVs were successfully endocytosed by HepG2 cells and promoted cell proliferation.

Conclusions:

• 0.5% ED-KSR is optimal for hiPSC culture for sEV production.
• Continuous 5-day supernatant collection is feasible, maintaining hiPSC viability and pluripotent characteristics.
• Both tested extraction methods yield biologically active sEVs suitable for therapeutic use.