Project description:Actin assembly and dynamics control the shape, motility and functions of diverse cell types. Programme for controlling theses dynamics is hard-coded into actin binding proteins and regulatory proteins. Refilins (RefilinA and RefilinB) are short lived regulatory proteins that interact with the actin-binding protein Filamin to convert it from an actin branching protein into one that bundles. We here show that different mechanisms converge to increase Refilin level in brain NG2+ precursor cells (polydendrocytes) committed to differentiate into the oligodendrocyte lineage. RefilinA is up-regulated through transcriptional activation during commitment into oligodendrocyte progenitor cells (OPC). RefilinB expression relies on PDGF signalling and is further stabilized by a unique auto-inhibitory domain masking the adjacent conserved PEST degradation signal. In NG2+ precursor cells and OPC, the RefilinB/Filamin complex localizes on filipodia protrusions and filipodial processes. Stable ectopic expression of Refilins in cells stimulates membrane remodelling dynamics linked with filipodia growth. These studies extend the function of the Refilin/FLNA complex to cell membrane remodelling linked with reorganization of underlying actin cytoskeleton. We performed whole transcriptomic analysis on the three cell population derived from OPC cells. Three different cultures were done and for each experiment we compared each cell population (NG2+, NG2+/A2B5 and O4) to the other 2 cell populations.
Project description:Actin assembly and dynamics control the shape, motility and functions of diverse cell types. Programme for controlling theses dynamics is hard-coded into actin binding proteins and regulatory proteins. Refilins (RefilinA and RefilinB) are short lived regulatory proteins that interact with the actin-binding protein Filamin to convert it from an actin branching protein into one that bundles. We here show that different mechanisms converge to increase Refilin level in brain NG2+ precursor cells (polydendrocytes) committed to differentiate into the oligodendrocyte lineage. RefilinA is up-regulated through transcriptional activation during commitment into oligodendrocyte progenitor cells (OPC). RefilinB expression relies on PDGF signalling and is further stabilized by a unique auto-inhibitory domain masking the adjacent conserved PEST degradation signal. In NG2+ precursor cells and OPC, the RefilinB/Filamin complex localizes on filipodia protrusions and filipodial processes. Stable ectopic expression of Refilins in cells stimulates membrane remodelling dynamics linked with filipodia growth. These studies extend the function of the Refilin/FLNA complex to cell membrane remodelling linked with reorganization of underlying actin cytoskeleton.
Project description:Oligodendrocytes undergo extensive changes as they differentiate from progenitors into myelinating cells. To better understand the; molecular mechanisms underlying this transformation, we performed a comparative analysis using gene expression profiling of A2B5+; oligodendrocyte progenitors and O4+ oligodendrocytes. Cells were sort-purified ex vivo from postnatal rat brain using flow cytometry. Using Affymetrix microarrays, 1707 transcripts were identified with a more than twofold increase in expression inO4+oligodendrocytes. Many genes required for oligodendrocyte differentiation were upregulated in O4+ oligodendrocytes, including numerous genes encoding; myelin proteins. Transcriptional changes included genes required for cell adhesion, actin cytoskeleton regulation, and fatty acid and; cholesterol biosynthesis. At the O4+ stage, there was an increase in expression of a novel proline-rich transmembrane protein (Prmp). Localized to the plasma membrane, Prmp displays adhesive properties that may be important for linking the extracellular matrix to the; actin cytoskeleton. Together, our results highlight the usefulness of this discovery-driven experimental strategy to identify genes relevant; to oligodendrocyte differentiation and myelination. Experiment Overall Design: Whole brain dissociates were prepared from one litter of 10 male postnatal day 7 rat pups for each of the 5 A2B5 bioligcal replicates and the 4 O4+ bioligical replicates. Total RNA was extracted from single A2B5+ and single O4+ cells sorted directly from postnatal day7 rat whole brain dissociates using flow cytometry.
Project description:MicroRNA profiling in subventricular zone after stroke: miR-124a regulates proliferation of neural progenitor cells through Notch signaling pathway