Biology subjects

Sanita, M. E.

Publications and source records attributed to Sanita, M. E..

3 recordsLinked to original sources

bioRxiv2025

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

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

biochemistry↗

bioRxiv2024

Charting the molecular landscape of neuronal organisation within the hippocampus using cryo electron tomography

Cellular cryo-electron tomography (cryoET) enables the capture of detailed structural information within a biologically relevant environment. However, information in more complex samples, such as tissues, is lacking. Importantly, these observations need to be set in context of populations; imaging on the molecular scale to-date is limited to few observations in-situ that struggle to be generalised. This is due to limitations in throughput and versatility employed by current instrumentation. Here, we utilise plasma focused ion beam milling to examine the molecular landscape of mouse hippocampus by cryoET in targeted regions across multiple individuals revealing the complex organisation of macromolecules from the CA1 strata pyramidale (sp) to radiatum (sr). Our data represent a molecular atlas, producing snapshots of hippocampal architecture in adult mouse. The combination of instrumentation and application of technical advancements provides a framework to explore specific structural questions within native tissues in a targeted manner.

biochemistry↗

bioRxiv2022

Three ALS genes regulate expression of the MHC class II antigen presentation pathway

Here we report that the major histocompatibility complex II (MHC II) antigen presentation pathway is regulated by the ALS-causative genes, FUS, TAF15, or MATR3. Of >6000 proteins detected by quantitative mass spectrometry, the subunits of the MHC II heterodimer, HLA-DR, were the top 2 downregulated proteins in HeLa knock outs (KO) of these ALS genes, but not the related gene, EWSR1. Moreover, CD74, which is the 3rd essential component of HLA-DR, was downregulated in the 3 KOs. We show that the downregulations are due to loss of CIITA, a transcription factor dedicated to expression of MHC II genes. Thus, our results reveal the 1st shared cellular pathway regulated by multiple ALS genes, and this pathway is ALS genes -> CIITA -> MHC II genes. We obtained the same results in HMC3 cells, a microglia cell line, showing that loss of the MHC II pathway extends to an ALS-relevant cell type in the central nervous system (CNS). Furthermore, the MHC II pathway is downregulated in hematopoietic progenitor cells (HPCs) bearing the ALS FUSR495X mutation. This observation may be highly significant to ALS pathogenesis as HPCs give rise to a multitude of CNS-specific and systemic immune cells, both of which have known or suspected roles in ALS. Together, our data raise the possibility that loss of the MHC II pathway in a large range of immune cells results in global failure of the immune system to protect motor neurons from damage that leads to the disease. Consequently, CIITA and the other genes in the MHC II pathway may be important new therapeutic targets for the disease.

molecular biology↗