Hypoxia induced lipid alterations in iPSC-derived human glial progenitor cells revealed by Matrix assisted laser desorption ionization mass spectrometry based cellular fingerprinting

Abstract

BackgroundIncreasing evidence suggests that the development of highly aggressive form of brain tumor "glioblastoma" contain cancer stem cells that closely resemble glial progenitor cells. The hypoxic microenvironment of tumors leads to metabolic reprogramming of cells, driving them towards more aggressive and treatment resistant state. To identify better targets for the effective removal of hypoxia adaptive cells, it is crucial to understand how these cells alter metabolism in hypoxic conditions. MethodsWe have used confocal microscopy to visualize mitochondrial morphology which confirmed hypoxia, and matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) to decipher lipid metabolic changes in iPSC-derived human glial progenitor cells induced by that hypoxia. ResultsOur findings revealed that hypoxia induced changes in mitochondrial morphology, interaction of mitochondria with lysosomes, and the expression of oxidized lipid species in iPSC-derived human glial progenitor cells. Hypoxic cells showed elongated mitochondria that resembled strings. MALDI-MSI based finger printing showed upregulation of oxidized phosphatidylethanolamine (PE): m/z 716.484 PE(33:1)+O, m/z 730.01 PE(34:1)+O, m/z 766.497 PE(37:5)+O, m/z 768.510 PE(37:4)+O, and oxidized phosphatidylcholine (PC): m/z 742.500 PC(32:2)+O, m/z 744.513 PC(33:2)+O, m/z 770.531 PC(34:2)+O), m/z 794.534 PC(34:1)+O, m/z 888.523 PC(42:11)+OH, and oxidized phosphatidic acid (PA): m/z 673.444 PA(33:2)+O, m/z 699.466 PA(35:3)+OH, m/z 725.531 PA(37:4)+OH in hypoxic cells. ConclusionsGiven the importance of glial progenitor cells in the central nervous system, as a precursor of glioblastoma, and their structural reliance on lipids, the molecular perturbations in the cell as a result of oxygen deficiency (hypoxia) remains unclear. The change in mitochondrial morphology showed that the cells were under hypoxic stress and mass spectrometry imaging unveiled important lipid metabolic changes in hypoxic iPSC-derived human glial progenitor cells as byproducts of oxidative stress, and provided insights that could lead to better treatment strategies for hypoxia-resistant cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/672639v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@873267org.highwire.dtl.DTLVardef@1fe4810org.highwire.dtl.DTLVardef@12d1aa3org.highwire.dtl.DTLVardef@30048f_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG Graphical abstract was created in BioRender https://app.biorender.com/illustrations/6822efb6aadd8c37669dd403