Matrix-assisted laser desorption/ionization imaging mass spectrometry reveals changes of phospholipid distribution in induced pluripotent stem cell colony differentiation.

Induced pluripotent stem cells (iPSCs) are opening up new possibilities for medicine. Understanding the regulation of iPSC biology is important when attempting to apply these cells to disease models or therapy. Changes of lipid metabolism in iPSCs were investigated by matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF-IMS). Analysis revealed changes of the intensity and distribution of peaks at m/z 782.5 and 798.5 in iPSC colonies during spontaneous differentiation. Two phosphatidylcholines (PCs) were identified: C ₄₄ H ₈₁ NO ₈ P, PC(36:4)[M+H]+ at m/z 782.5 and C ₄₂ H ₈₂ NO ₈ P, PC(34:1)[M+K]+ at m/z 798.5. The intensity of PC(36:4) showed an inverse relation between undifferentiated and differentiated iPSC colonies. PC(34:1) displayed a diffuse distribution in undifferentiated iPSC colonies, while it showed a concentric distribution in differentiated iPSC colonies, and was localized at the border of the differentiated and undifferentiated areas or the border between undifferentiated iPSC and feeder cells. These findings suggested that the distribution of lipids changes during the growth and differentiation of iPSCs and that MALDI-TOF-IMS was useful for analyzing these changes. PC(36:4) might play a role in maintaining pluripotency, while PC(34:1) might play a role in the differentiation and spread of iPSCs. Graphical Abstract MALDI Imaging for phosphatidylcholine distribution changes during sponteneous differentiaton of induced pluiripotent stem cells colonies.