Visualizing Intrapopulation Hematopoietic Cell Heterogeneity with Self-Organizing Maps of SIMS Data

Area of Science:

• Biochemistry
• Cell Biology
• Immunology

Background:

• Understanding stem cell heterogeneity is vital for stem cell expansion and differentiation.
• Hematopoietic stem and progenitor cells (HSPCs) exhibit varying differentiation potentials.
• Characterizing spectral differences in cell populations aids in functional analysis.

Purpose of the Study:

• To assess if self-organizing maps (SOMs) of single-cell mass spectrometry data can reveal spectral and functional heterogeneity within hematopoietic cell populations.
• To investigate age-related spectral variations in different hematopoietic cell types.

Main Methods:

• Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used for single-cell spectral analysis.
• Self-organizing maps (SOMs) were applied to TOF-SIMS data from hematopoietic stem and progenitor cells (HSPCs), common lymphoid progenitors (CLPs), and B cells.
• Unified distance matrix (U-matrix) was used to visualize spectral variation.

Main Results:

• CLPs showed the highest intrapopulation spectral variation, irrespective of donor age.
• HSPCs exhibited the most significant age-related spectral variation, while B cells showed the least.
• SOMs effectively characterized spectral heterogeneity between and within hematopoietic cell populations.

Conclusions:

• SOMs of single-cell TOF-SIMS spectra are effective tools for characterizing cellular heterogeneity.
• This approach provides insights into spectral and functional differences along differentiation pathways.
• The findings support the use of SOMs for designing improved stem cell expansion cultures.