Gender-specific effects of transthyretin on neural stem cell fate in the subventricular zone of the adult mouse

AbstractChoroid plexus epithelial cells produce and secrete transthyretin (TTR). TTR binds and distributes thyroid hormone (TH) to brain cells via the cerebrospinal fluid. The adult murine subventricular zone (SVZ) is in close proximity to the choroid plexus. In the SVZ, TH determines neural stem cell (NSC) fate towards a neuronal or a glial cell. We investigated whether the loss of TTR also disrupted NSC fate choice. Our results show a decreased neurogenic versus oligodendrogenic balance in the lateroventral SVZ of Ttr knockout mice. This balance was also decreased in the dorsal SVZ, but only in Ttr knockout male mice, concomitant with an increased oligodendrocyte precursor density in the corpus callosum. Quantitative RTqPCR analysis following FACS-dissected SVZs, or marked-coupled microbeads sorting of in vitro neurospheres, showed elevated Ttr mRNA levels in neuronal cells, as compared to uncommitted precursor and glial cells. However, TTR protein was undetectable in vivo using immunostaining, and this despite the presence of Ttr mRNA-expressing SVZ cells. Altogether, our data demonstrate that TTR is an important factor in SVZ neuro- and oligodendrogenesis. They also reveal important gender-specific differences and spatial heterogeneity, providing new avenues for stimulating endogenous repair in neurodegenerative diseases.

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miR-17~92 exerts stage-specific effects in adult V-SVZ neural stem cell lineages

10.1101/2021.07.28.454109 ◽

2021 ◽

Author(s):

Fabrizio Favaloro ◽

Annina DeLeo ◽

Ana Delgado ◽

Fiona Doetsch

Keyword(s):

Stem Cell ◽

Neural Stem Cell ◽

Oligodendrocyte Progenitor Cells ◽

Dependent Manner ◽

Cell Lineages ◽

Conditional Deletion ◽

Specific Effects ◽

Cell Type Specific

In the adult mouse brain, neural stem cells (NSCs) in the ventricular-subventricular zone (V-SVZ) generate neurons and glia throughout life. microRNAs are important regulators of cell states, frequently acting in a stage- or context-dependent manner. Here, miRNA profiling of FACS-purified populations identified miR-17~92 as highly upregulated in activated NSCs and transit amplifying cells (TACs) in comparison to quiescent NSCs. Conditional deletion of miR-17~92 in NSCs reduced stem cell proliferation both in vitro and in vivo. In contrast, in TACs, miR-17~92 deletion caused a selective shift from neurogenic DLX2+ TACs towards oligodendrogenic OLIG2+ TACs, resulting in increased oligodendrogenesis to the corpus callosum. miR-17~92 deletion also decreased proliferation and maturation of intraventricular oligodendrocyte progenitor cells. Together, these findings reveal stage- and cell-type- specific functions of the miR-17~92 cluster within adult V-SVZ neural stem cell lineages.

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Effect of the 3D Artificial Nichoid on the Morphology and Mechanobiological Response of Mesenchymal Stem Cells Cultured In Vitro

Cells ◽

10.3390/cells9081873 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1873 ◽

Cited By ~ 3

Author(s):

Andrea Remuzzi ◽

Barbara Bonandrini ◽

Matteo Tironi ◽

Lorena Longaretti ◽

Marina Figliuzzi ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Cultured Cells ◽

Three Dimensions ◽

Nuclear Pore ◽

Cells Cultured

Stem cell fate and behavior are affected by the bidirectional communication of cells and their local microenvironment (the stem cell niche), which includes biochemical cues, as well as physical and mechanical factors. Stem cells are normally cultured in conventional two-dimensional monolayer, with a mechanical environment very different from the physiological one. Here, we compare culture of rat mesenchymal stem cells on flat culture supports and in the “Nichoid”, an innovative three-dimensional substrate micro-engineered to recapitulate the architecture of the physiological niche in vitro. Two versions of the culture substrates Nichoid (single-layered or “2D Nichoid” and multi-layered or “3D Nichoid”) were fabricated via two-photon laser polymerization in a biocompatible hybrid organic-inorganic photoresist (SZ2080). Mesenchymal stem cells, isolated from rat bone marrow, were seeded on flat substrates and on 2D and 3D Nichoid substrates and maintained in culture up to 2 weeks. During cell culture, we evaluated cell morphology, proliferation, cell motility and the expression of a panel of 89 mesenchymal stem cells’ specific genes, as well as intracellular structures organization. Our results show that mesenchymal stem cells adhered and grew in the 3D Nichoid with a comparable proliferation rate as compared to flat substrates. After seeding on flat substrates, cells displayed large and spread nucleus and cytoplasm, while cells cultured in the 3D Nichoid were spatially organized in three dimensions, with smaller and spherical nuclei. Gene expression analysis revealed the upregulation of genes related to stemness and to mesenchymal stem cells’ features in Nichoid-cultured cells, as compared to flat substrates. The observed changes in cytoskeletal organization of cells cultured on 3D Nichoids were also responsible for a different localization of the mechanotransducer transcription factor YAP, with an increase of the cytoplasmic retention in cells cultured in the 3D Nichoid. This difference could be explained by alterations in the import of transcription factors inside the nucleus due to the observed decrease of mean nuclear pore diameter, by transmission electron microscopy. Our data show that 3D distribution of cell volume has a profound effect on mesenchymal stem cells structure and on their mechanobiological response, and highlight the potential use of the 3D Nichoid substrate to strengthen the potential effects of MSC in vitro and in vivo.

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Deterministic Trigger of Self-Renewal in Expanded HSCs Expressing Hoxb4 + Antisense Pbx1.

Blood ◽

10.1182/blood.v106.11.800.800 ◽

2005 ◽

Vol 106 (11) ◽

pp. 800-800

Author(s):

Sonia Cellot ◽

Jana Krosl ◽

Keith Humphries ◽

Guy Sauvageau

Keyword(s):

Cell Proliferation ◽

Stem Cell ◽

Cell Fate ◽

Time Course ◽

Cell Cycle Distribution ◽

Self Renewal ◽

Primary Mouse ◽

The Impact

Abstract We previously reported the generation of pluripotent and ultracompetitive HSCs through modulation of Hoxb4 and Pbx1 levels. These Hoxb4hiPbx1lo HSCs display a tremendous regenerative potential, yet they are still fully responsive to in vivo regulatory signals that control stem cell pool size (20 000 HSCmouse) and differentiation pathways. Further work in our laboratory attempted to circumvent these physiological constraints by expanding Hoxb4hiPbx1lo transduced HSCs in vitro, and hence revealing their intrinsic expansion potential. Independent experiments were performed where primary mouse BM cells were co-infected with retroviruses encoding antisense Pbx1 cDNA plus YFP, and Hoxb4 plus GFP (double gene transfer ranged between 20–50%). Hoxb4hiPbx1lo HSCs measured using the CRU assay expanded by 105-fold during a 12 day in vitro culture. Following serial transplantations, these cells displayed an additional 4–5 log expansion in vivo. Total stem cell content per animal remained within normal limits. Southern blot analyses of proviral integrations showed that the expansion was polyclonal, and analyses of individually expanded clones provided a molecular proof of in vitro self-renewal (SR). This unprecedented level of HSC expansion in such a short time course (105-fold in 12 days) implies an absolute HSC doubling time of approximately 17 hours in our culture, raising the possibility that virtually all dividing HSCs undergo self-renewal. This analysis prompted us to dissect the impact of Hoxb4 on cell proliferation versus cell fate (SR?). When analyzed during the period of maximal HSC expansion, the cell cycle distribution of Sca+ or Sca+Lin− cells were comparable between the cultures initiated with neo control versus Hoxb4 BM cells (CTL vs Hoxb4: G0/G1: 66% vs 83%; S: 15% vs 9%; G2/M: 18% vs 7%). Correspondingly, CFSE tracking studies confirmed the identical, or even lower, number of cellular divisions in Sca+ cells isolated from cultures initiated with Hoxb4 versus neo transduced cells. Annexin V studies precluded protection from apoptosis as the major mechanism to increase HSC numbers since similar results (3–10% positive cells) were observed in the Hoxb4 versus neo-transduced cells. In summary, our studies support the emerging concept that distinct molecular pathways regulate cell proliferation and self-renewal, suggesting that Hoxb4 + antisense Pbx1 predominantly triggers self-renewal over HSC proliferation.

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Brain micro-ecologies: neural stem cell niches in the adult mammalian brain

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2006.2016 ◽

2007 ◽

Vol 363 (1489) ◽

pp. 123-137 ◽

Cited By ~ 172

Author(s):

Patricio A Riquelme ◽

Elodie Drapeau ◽

Fiona Doetsch

Keyword(s):

Stem Cell ◽

Cell Fate ◽

Neural Stem Cell ◽

Subventricular Zone ◽

Hippocampal Formation ◽

Mammalian Brain ◽

Adult Neural Stem Cell ◽

Stem Cell Fate ◽

Stem Cell Niches ◽

Adult Mammalian Brain

Neurogenesis persists in two germinal regions in the adult mammalian brain, the subventricular zone of the lateral ventricles and the subgranular zone in the hippocampal formation. Within these two neurogenic niches, specialized astrocytes are neural stem cells, capable of self-renewing and generating neurons and glia. Cues within the niche, from cell–cell interactions to diffusible factors, are spatially and temporally coordinated to regulate proliferation and neurogenesis, ultimately affecting stem cell fate choices. Here, we review the components of adult neural stem cell niches and how they act to regulate neurogenesis in these regions.

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Multifunctional silica-coated iron oxide nanoparticles: a facile four-in-one system for in situ study of neural stem cell harvesting

Faraday Discussions ◽

10.1039/c4fd00132j ◽

2014 ◽

Vol 175 ◽

pp. 13-26 ◽

Cited By ~ 15

Author(s):

Yung-Kang Peng ◽

Cathy N. P. Lui ◽

Tsen-Hsuan Lin ◽

Chen Chang ◽

Pi-Tai Chou ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Iron Oxide ◽

Magnetic Resonance ◽

Neural Stem Cells ◽

Neural Stem Cell ◽

Cell Therapies ◽

Bimodal Imaging

Neural stem cells (NSCs), which generate the main phenotypes of the nervous system, are multipotent cells and are able to differentiate into multiple cell types via external stimuli from the environment. The extraction, modification and re-application of NSCs have thus attracted much attention and raised hopes for novel neural stem cell therapies and regenerative medicine. However, few studies have successfully identified the distribution of NSCs in a live brain and monitored the corresponding extraction processes both in vitro and in vivo. To address those difficulties, in this study multi-functional uniform nanoparticles comprising an iron oxide core and a functionalized silica shell (Fe3O4@SiO2(FITC)-CD133, FITC: a green emissive dye, CD133: anti-CD133 antibody) have been strategically designed and synthesized for use as probe nanocomposites that provide four-in-one functionality, i.e., magnetic agitation, dual imaging (both magnetic resonance and optical) and specific targeting. It is shown that these newly synthesized Fe3O4@SiO2(FITC)-CD133 particles have clearly demonstrated their versatility in various applications. (1) The magnetic core enables magnetic cell collection and T2 magnetic resonance imaging. (2) The fluorescent FITC embedded in the silica framework enables optical imaging. (3) CD133 anchored on the outermost surface is demonstrated to be capable of targeting neural stem cells for cell collection and bimodal imaging.

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Constructing stem cell microenvironments using bioengineering approaches

Physiological Genomics ◽

10.1152/physiolgenomics.00099.2013 ◽

2013 ◽

Vol 45 (23) ◽

pp. 1123-1135 ◽

Cited By ~ 29

Author(s):

David A. Brafman

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Fate ◽

Disease Modeling ◽

Mechanical Stimuli ◽

Culture Methods ◽

Stem Cell Fate ◽

And Function

Within the adult organism, stem cells reside in defined anatomical microenvironments called niches. These architecturally diverse microenvironments serve to balance stem cell self-renewal and differentiation. Proper regulation of this balance is instrumental to tissue repair and homeostasis, and any imbalance can potentially lead to diseases such as cancer. Within each of these microenvironments, a myriad of chemical and physical stimuli interact in a complex (synergistic or antagonistic) manner to tightly regulate stem cell fate. The in vitro replication of these in vivo microenvironments will be necessary for the application of stem cells for disease modeling, drug discovery, and regenerative medicine purposes. However, traditional reductionist approaches have only led to the generation of cell culture methods that poorly recapitulate the in vivo microenvironment. To that end, novel engineering and systems biology approaches have allowed for the investigation of the biological and mechanical stimuli that govern stem cell fate. In this review, the application of these technologies for the dissection of stem cell microenvironments will be analyzed. Moreover, the use of these engineering approaches to construct in vitro stem cell microenvironments that precisely control stem cell fate and function will be reviewed. Finally, the emerging trend of using high-throughput, combinatorial methods for the stepwise engineering of stem cell microenvironments will be explored.

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