Cell motility of neural stem cells is reduced after SPIO-labeling, which is mitigated after exocytosis

Area of Science:

• Biomedical Engineering
• Neuroscience
• Stem Cell Biology

Background:

• Magnetic Resonance Imaging (MRI) is a key tool for tracking superparamagnetic iron oxide (SPIO)-labeled cells in vivo.
• Previous studies indicate that long-term MRI tracking of rapidly dividing cells may underestimate their actual migration distance.

Purpose of the Study:

• To investigate the impact of SPIO labeling on neural stem cell (NSC) motility and migration.
• To determine the mechanisms behind MRI's underestimation of cell migration in SPIO-labeled cells.

Main Methods:

• Time-lapse microscopy was employed to assess random cellular motility and cell division in SPIO-labeled and unlabeled NSCs.
• SPIO-labeled NSCs and human induced pluripotent stem cells were transplanted into mouse brains to observe migration patterns.
• Cell viability, proliferation, and apoptosis were evaluated in labeled and unlabeled cells.

Main Results:

• SPIO labeling did not affect NSC viability, proliferation, or apoptosis, with cells dividing symmetrically.
• SPIO-labeled NSCs exhibited significantly reduced motility compared to unlabeled controls.
• Post-transplantation, rapid SPIO exocytosis was observed, and SPIO-depleted cells demonstrated greater migration distances.

Conclusions:

• MRI underestimation of cell migration is not solely due to label dilution but also significantly influenced by reduced cell motility caused by SPIO labeling.
• SPIO exocytosis by transplanted cells mitigates the reduced motility, allowing for more accurate assessment of migration.
• These findings highlight the importance of considering SPIO-labeling effects on cell behavior for accurate in vivo cell tracking studies.