Project description:Adult oligodendrocyte progenitors (aOPCs) share with their neonatal counterpart (nOPC) the ability to give rise to myelinating oligodendrocytes, but they also display unique functional features. This study addresses the molecular mechanisms underlying the intrinsic differences between these two populations. Using RNA-sequencing and unbiased histone proteomics analysis performed on PDGFRa+ OPCs sorted from a reporter mouse, we define the unique transcriptome and histone marks of aOPCs. We describe the higher levels of genes related to lipid metabolism and myelin sheath, and lower expression of genes related to cycle and proliferation in aOPCs compared to nOPCs. We also identify greater levels of activating H4K8ac and repressive H4K20me3 histone marks in aOPCs compared to nOPCs, and increased occupancy of H4K8ac mark at chromatin locations corresponding to oligodendrocyte-specific genes. Pharmacological inhibition of histone acetylation in neonatal O4+OPCs (nO4+OPCs) and adult O4+OPCs (aO4+OPCs) followed by RNA-sequencing showed a moderate change in the transcriptome of these cells resulting in the decrease of proliferation capacity in aO4+OPCs but not nO4+OPCs. Pharmacological inhibition of H4K20me3 mark was not sufficient to change the transcriptome or functional properties of nO4+OPCs and aO4+OPC. Overall, this study identifies histone acetylation as key in regulating the proliferation of aO4+OPCs.
Project description:Human fetal tissue dissociates between 18-22wk gestational age were FACS sorted on the basis of CD140a (PDGFRA) and O4 antigens. Each population was profiled immediately following FACS.
Project description:Human fetal tissue dissociates between 18-22wk gestational age were FACS sorted on the basis of CD140a (PDGFRA) and O4 antigens. Each population was profiled immediately following FACS. 20 samples, 4 groups (FACS-sorted cell populations), between 3 and 6 replicates in each group, each replicate is from a separate patient sample
Project description:To investigate how ZFP488 regulates myelination, we performed transcriptome profiling on OLs (O4+GalC+) isolated from the cortices of control and Zfp488KI/KI mice at P5 using fluorescence activated cell sorting.
Project description:Premature birth is frequently associated with abnormal brain development, leading to brain damage, the most common being diffuse white matter injury. Perinatal neuroinflammation, which relies primarily on microglial activation, contributes to the myelination failure by affecting oligodendrocytes. To better understand the pathophysiological mechanisms involved in encephalopathy of prematurity, we took advantage of a mouse model in which systemic injections of proinflammatory interleukin-1β (IL1B) disrupt oligodendrocyte differentiation, leading to hypomyelination and cognitive deficits. Newborn mice received intraperitoneal injections of IL1B from postnatal day (P) 1 to P5. At P5 and P10, brains were collected from six control (PBS) and six exposed (IL1B) mice; oligodendrocytes and microglial cells were sequentially isolated using antibodies coupled to magnetic beads targeting O4 and CD11b, respectively. Gene expression analysis performed on Agilent microarray revealed that perinatal inflammation induced major changes in gene expression in both cell types. By improving our understanding of the cellular mechanisms involved in encephalopathy of prematurity, this study could ultimately help design neuroprotective strategies.
Project description:Mfsd2a plays an important role in accretion of essential fatty acids such as docosahexaenoic acid (DHA) from the periphery into the brain. Loss of Mfsd2a in humans leads to microcephaly and hypomyelination. The precise impact of lipid species transported by Mfsd2a on myelination is not known. Using OPC specific deletion of Mfsd2a (2aOKO) in mice we found that OPC cell state, differentiation and oligodendrocytes maturation is disrupted resulting in hypomyelination. RNAsequencing and differential gene expression analysis was performed on OPC and O4 cells from postnatal mouse brain to understand the influence of Mfsd2a on oligodendrocyte development.
Project description:O2- and O4-alkylated thymidine lesions are known to be poorly repaired and persist in mammalian tissues. To understand how mammalian cells sense the presence and regulate the repair of these lesions, we employed a stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomic method to discover novel O2- and O4-n-butylthymidine (O2- and O4-nBudT)-binding proteins. We were able to identify 21 and 74 candidate DNA damage recognition proteins for O2-nBudT- and O4-nBudT-bearing DNA probes, respectively. Among these proteins, DDB1 and DDB2 selectively bind to O2-nBudT-containing DNA, whereas three HMG-box-containing proteins (i.e. HMGB1, HMGB2 and TFAM) exhibit preferential binding to O4-nBudT-bearing DNA. We further confirmed, by employing electrophoretic mobility shift assay, that TFAM can bind selectively and directly with O4-alkyldT-harboring DNA, and the binding capacity depends mainly on the HMG box-A domain of TFAM. We also found that TFAM promotes transcriptional mutagenesis of O4-alkyldT lesions in vitro and in human cells. Together, we explored, for the first time, the interactomes of O-alkyldT lesions. Our study also expands the functions of TFAM by revealing its capability in binding to O4-alkyldT-bearing DNA, demonstrating the role of HMG-box A domain in this molecular recognition, and uncovering its modulation of transcriptional mutagenesis of these lesions in human cells.