Monitoring of embryonic stem cell differentiation trajectories by intact cell mass spectrometry.

Human embryonic stem cells (hESCs) represent a promising tool for clinical applications. hESCs differentiation to relevant cell types is a gradual process, where final phenotype is achieved. However, substantial heterogeneity in differentiation process may produce aberrant cells with unwanted properties, such as lack of functional phenotype, or propensity to cancer growth. Early lung progenitors (ELEPs) are direct precursors of mature lung cells (pneumocytes) that differentiate from hESCs under specific conditions through several stages. Differentiation pathway can be outlined specifically by molecular markers, but an unbiased, sensitive and robust tool for discrimination of ELEPs from pluripotent or transitional stages is still missing. Here we demonstrate that intact cell MALDI TOF mass spectrometry may provide such a tool for quality control.