USP9X enhances the polarity and self-renewal of embryonic stem cell-derived neural progenitors.
The substrate-specific deubiquitylating enzyme USP9X is a putative "stemness" gene expressed in many progenitor cell populations. To test its function in embryonic stem cell-derived neural progenitor/stem cells, we expressed USP9X from a Nestin promoter. Elevated USP9X levels resulted in two phenomena. First, it produced a dramatically altered cellular architecture wherein the majority (>80%) of neural progenitors was arranged into radial clusters. These progenitors expressed markers of radial glial cells and were highly polarized with adherens junction proteins (N-cadherin, beta-catenin, and AF-6) and apical markers (Prominin1, atypical protein kinase C-zeta) as well as Notch, Numb, and USP9X itself, concentrated at the center. The cluster centers were also devoid of nuclei and so resembled the apical end-feet of radial progenitors in the neural tube. Second, USP9X overexpression caused a fivefold increase in the number of radial progenitors and neurons, in the absence of exogenous growth factors. 5-Bromo-2'-deoxyuridine labeling, as well as the examination of the brain lipid-binding protein:betaIII-tubulin ratio, indicated that nestin-USP9X enhanced the self-renewal of radial progenitors but did not block their subsequent differentiation to neurons and astrocytes. nestin-USP9X radial progenitors reformed clusters after passage as single cells, whereas control cells did not, suggesting it aids the establishment of polarity. We propose that USP9X-induced polarization of these neural progenitors results in their radial arrangement, which provides an environment conducive for self-renewal.
Jolly
Lachlan A
LA
Child Health Research Institute, North Adelaide, South Australia 5006, Australia.
Taylor
Verdon
V
Wood
Stephen A
SA
D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002449:Cell Aggregation; D002454:Cell Differentiation; D016764:Cell Polarity; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D007381:Intermediate Filament Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D016548:Prosencephalon / Q000166:cytology; D021381:Protein Transport; D043222:Ubiquitin Thiolesterase
D015415:Biomarkers; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; D010450:Endopeptidases; D043222:Ubiquitin Thiolesterase; C404328:Usp9x protein, mouse