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Cells Jun 2019Neuronal migration is essential for the orchestration of brain development and involves several contiguous steps: interkinetic nuclear movement (INM), multipolar-bipolar... (Review)
Review
Neuronal migration is essential for the orchestration of brain development and involves several contiguous steps: interkinetic nuclear movement (INM), multipolar-bipolar transition, locomotion, and translocation. Growing evidence suggests that Rho GTPases, including RhoA, Rac, Cdc42, and the atypical Rnd members, play critical roles in neuronal migration by regulating both actin and microtubule cytoskeletal components. This review focuses on the spatiotemporal-specific regulation of Rho GTPases as well as their regulators and effectors in distinct steps during the neuronal migration process. Their roles in bridging extracellular signals and cytoskeletal dynamics to provide optimal structural support to the migrating neurons will also be discussed.
Topics: Adherens Junctions; Animals; Cell Movement; Ependymoglial Cells; Humans; Neurogenesis; Neurons; cdc42 GTP-Binding Protein; rho GTP-Binding Proteins
PubMed: 31185627
DOI: 10.3390/cells8060568 -
EBioMedicine Mar 2022Visual impairments are a critical medical hurdle to be addressed in modern society. Müller glia (MG) have regenerative potential in the retina in lower vertebrates, but...
BACKGROUND
Visual impairments are a critical medical hurdle to be addressed in modern society. Müller glia (MG) have regenerative potential in the retina in lower vertebrates, but not in mammals. However, in mice, in vivo cell fusion between MG and adult stem cells forms hybrids that can partially regenerate ablated neurons.
METHODS
We used organotypic cultures of human retina and preparations of dissociated cells to test the hypothesis that cell fusion between human MG and adult stem cells can induce neuronal regeneration in human systems. Moreover, we established a microinjection system for transplanting human retinal organoids to demonstrate hybrid differentiation.
FINDINGS
We first found that cell fusion occurs between MG and adult stem cells, in organotypic cultures of human retina as well as in cell cultures. Next, we showed that the resulting hybrids can differentiate and acquire a proto-neural electrophysiology profile when the Wnt/beta-catenin pathway is activated in the adult stem cells prior fusion. Finally, we demonstrated the engraftment and differentiation of these hybrids into human retinal organoids.
INTERPRETATION
We show fusion between human MG and adult stem cells, and demonstrate that the resulting hybrid cells can differentiate towards neural fate in human model systems. Our results suggest that cell fusion-mediated therapy is a potential regenerative approach for treating human retinal dystrophies.
FUNDING
This work was supported by La Caixa Health (HR17-00231), Velux Stiftung (976a) and the Ministerio de Ciencia e Innovación, (BFU2017-86760-P) (AEI/FEDER, UE), AGAUR (2017 SGR 689, 2017 SGR 926).
Topics: Adult Stem Cells; Animals; Cell Differentiation; Ependymoglial Cells; Humans; Mammals; Mice; Neuroglia; Retina
PubMed: 35278743
DOI: 10.1016/j.ebiom.2022.103914 -
Translational Vision Science &... Jan 2022Because the importance of glia in regulating brain functions has been demonstrated, genetic technologies that manipulate glial cell-specific gene expression in the brain...
PURPOSE
Because the importance of glia in regulating brain functions has been demonstrated, genetic technologies that manipulate glial cell-specific gene expression in the brain have become essential and have made great progress. However, it is unknown whether the same strategy that is used in the brain can be applied to the retina because retinal glia differs from glia in the brain. Here, we aimed to find a method for selective gene expression in Müller cells (characteristic glial cells in the retina) and identified Mlc1 as a specific promoter of Müller cells.
METHODS
Mlc1-tTA::Yellow-Cameleon-NanotetO/tetO (YC-Nano) mice were used as a reporter line. YC-Nano, a fluorescent protein, was ectopically expressed in the cell type controlled by the Mlc1 promotor. Immunofluorescence staining was used to identify the cell type expressing YC-Nano protein.
RESULTS
YC-Nano-positive (+) signals were observed as vertical stalks in the sliced retina and spanned from the nerve fiber layer through the outer nuclear layer. The density of YC-Nano+ cells was higher around the optic nerve head and lower in the peripheral retina. The YC-Nano+ signals colocalized with vimentin, a marker of Müller cells, but not with the cell markers for blood vessels, microglia, neurons, or astrocytes.
CONCLUSIONS
The Mlc1 promoter allows us to manipulate gene expression in Müller cells without affecting astrocytes in the retina.
TRANSLATIONAL RELEVANCE
Gene manipulation under control of Mlc1 promoter offers novel technique to investigate the role of Müller cells.
Topics: Animals; Astrocytes; Ependymoglial Cells; Gene Expression; Membrane Proteins; Mice; Neuroglia; Retina
PubMed: 35040915
DOI: 10.1167/tvst.11.1.25 -
FEBS Letters Dec 2017The mammalian cerebral cortex is responsible for higher cognitive functions such as perception, consciousness, and acquiring and processing information. The neocortex is... (Review)
Review
The mammalian cerebral cortex is responsible for higher cognitive functions such as perception, consciousness, and acquiring and processing information. The neocortex is organized into six distinct laminae, each composed of a rich diversity of cell types which assemble into highly complex cortical circuits. Radial glia progenitors (RGPs) are responsible for producing all neocortical neurons and certain glia lineages. Here, we discuss recent discoveries emerging from clonal lineage analysis at the single RGP cell level that provide us with an inaugural quantitative framework of RGP lineage progression. We further discuss the importance of the relative contribution of intrinsic gene functions and non-cell-autonomous or community effects in regulating RGP proliferation behavior and lineage progression.
Topics: Animals; Cell Differentiation; Cell Lineage; Cell Tracking; Ependymoglial Cells; Humans; Neural Stem Cells; Neurogenesis; Signal Transduction; Single-Cell Analysis
PubMed: 29121403
DOI: 10.1002/1873-3468.12906 -
Experimental Eye Research May 2021Others have previously reported that global loss of toll-like receptor 4 (TLR4) reduced retinal inflammation. To determine cell specific actions of TLR4 in the retina,...
Others have previously reported that global loss of toll-like receptor 4 (TLR4) reduced retinal inflammation. To determine cell specific actions of TLR4 in the retina, we generated diabetic endothelial cell specific and Müller cell specific TLR4 knockout mice. Diabetic Cdh5-Cre TLR4 mice, PDGFRα-Cre TLR4 mice, and TLR4 floxed mice were evaluated for retinal permeability, neuronal damage, and numbers of degenerate capillaries, all changes commonly observed in the diabetic retina. We also measured protein levels of key inflammatory mediators. We found that diabetes increased permeability, neuronal, and vascular damage in all mice. Loss of TLR4 in the retinal endothelial cells protected against these changes when compared to diabetic TLR4 floxed mice. In contrast, loss of TLR4 in Müller cells did not reduce diabetes-induced increases in permeability or neuronal and vascular damage. Elimination of TLR4 in either mouse model reduced inflammatory mediators, as well as VEGF levels. Taken together, our findings suggest that loss of TLR4 in endothelial cells is protective against diabetic-induced damage, while Müller cell TLR4 is not involved in the damage.
Topics: Animals; Capillaries; Capillary Permeability; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Endothelial Cells; Ependymoglial Cells; Mice; Mice, Knockout; Retinal Vessels; Signal Transduction; Toll-Like Receptor 4
PubMed: 33789141
DOI: 10.1016/j.exer.2021.108557 -
Biomolecules May 2021To investigate the mechanism of vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) in Müller cell (MC) viability and neuroprotection...
To investigate the mechanism of vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) in Müller cell (MC) viability and neuroprotection in diabetic retinopathy (DR), we examined the role of VEGF in MC viability and BDNF production, and the effect of BDNF on MC viability under diabetic conditions. Mouse primary MCs and cells of a rat MC line, rMC1, were used in investigating MC viability and BDNF production under diabetic conditions. VEGF-stimulated BDNF production was confirmed in mice. The mechanism of BDNF-mediated MC viability was examined using siRNA knockdown. Under diabetic conditions, recombinant VEGF (rVEGF) stimulated MC viability and BDNF production in a dose-dependent manner. rBDNF also supported MC viability in a dose-dependent manner. Targeting BDNF receptor tropomyosin receptor kinase B (TRK-B) with siRNA knockdown substantially downregulated the activated (phosphorylated) form of serine/threonine-specific protein kinase (AKT) and extracellular signal-regulated kinase (ERK), classical survival and proliferation mediators. Finally, the loss of MC viability in siRNA transfected cells under diabetic conditions was rescued by rBDNF. Our results provide direct evidence that VEGF is a positive regulator for BDNF production in diabetes for the first time. This information is essential for developing BDNF-mediated neuroprotection in DR and hypoxic retinal diseases, and for improving anti-VEGF treatment for these blood-retina barrier disorders, in which VEGF is a major therapeutic target for vascular abnormalities.
Topics: Animals; Brain-Derived Neurotrophic Factor; Cell Survival; Cells, Cultured; Diabetic Retinopathy; Ependymoglial Cells; Mice; Neuroprotective Agents; Rats; Receptor, trkB; Signal Transduction; Vascular Endothelial Growth Factor A; Xenotropic and Polytropic Retrovirus Receptor
PubMed: 34068807
DOI: 10.3390/biom11050712 -
International Journal of Molecular... Mar 2017Anti-vascular endothelial growth factor (VEGF) therapy has revolutionized the treatment of retinal vascular diseases. However, constitutive VEGF also acts as a trophic...
Anti-vascular endothelial growth factor (VEGF) therapy has revolutionized the treatment of retinal vascular diseases. However, constitutive VEGF also acts as a trophic factor on retinal nonvascular cells. We have studied the effects of aflibercept and ranibizumab on human Müller cells and photoreceptors exposed to starvation media containing various concentrations of glucose, with or without CoCl2-induced hypoxia. Cell survival was assessed by calcein-AM cell viability assays. Expression of heat shock proteins (Hsp) and redox proteins thioredoxin 1 and 2 (TRX1, TRX2) was studied by Western blots. The production of neurotrophic factors in Müller cells and interphotoreceptor retinoid-binding protein (IRBP) in photoreceptors was measured by enzymelinked immunosorbent assays. Aflibercept and ranibizumab did not affect the viability of both types of cells. Neither aflibercept nor ranibizumab affected the production of neurotrophic factors or expression of Hsp60 and Hsp90 in Müller cells. However, aflibercept but not ranibizumab affected the expression of Hsp60, Hsp9, TRX1 and TRX2 in photoreceptors. Aflibercept and ranibizumab both inhibited the production of IRBP in photoreceptors, aflibercept more so than ranibizumab. Our data indicates that the potential influence of aflibercept and ranibizumab on photoreceptors should be specifically monitored in clinical studies.
Topics: Angiogenesis Inhibitors; Cell Survival; Cells, Cultured; Ependymoglial Cells; Eye Proteins; Gene Expression; Glucose; Heat-Shock Proteins; Humans; Hypoxia; Nerve Growth Factors; Photoreceptor Cells; Ranibizumab; Receptors, Vascular Endothelial Growth Factor; Recombinant Fusion Proteins; Retinol-Binding Proteins; Stress, Physiological; Thioredoxins
PubMed: 28257068
DOI: 10.3390/ijms18030533 -
Optics Express Dec 2014Light is being detected by the two distinct types of photoreceptors in the human retina: cones and rods. Before light arrives at the photoreceptors, it must traverse the...
Light is being detected by the two distinct types of photoreceptors in the human retina: cones and rods. Before light arrives at the photoreceptors, it must traverse the whole retina, along its array of higher-index Müller cells serving as natural waveguides. Here we analyze this optical process of light propagation through Müller cells by two independent optical methods: numerical beam propagation and analytical modal analysis. We show that the structure and refractive index profile of the Müller cells create a unique spatio-spectral distribution of light. This distribution corresponds to the positions and spectral sensitivities of both cones and rods to improve their light absorption.
Topics: Color Perception; Computer Simulation; Ependymoglial Cells; Humans; Light; Models, Neurological; Refractometry; Retina; Retinal Cone Photoreceptor Cells; Scattering, Radiation
PubMed: 25607186
DOI: 10.1364/OE.22.032208 -
Nature Communications Jan 2024Rare cell populations are key in neoplastic progression and therapeutic response, offering potential intervention targets. However, their computational identification...
Rare cell populations are key in neoplastic progression and therapeutic response, offering potential intervention targets. However, their computational identification and analysis often lag behind major cell types. To fill this gap, we introduce MarsGT: Multi-omics Analysis for Rare population inference using a Single-cell Graph Transformer. It identifies rare cell populations using a probability-based heterogeneous graph transformer on single-cell multi-omics data. MarsGT outperforms existing tools in identifying rare cells across 550 simulated and four real human datasets. In mouse retina data, it reveals unique subpopulations of rare bipolar cells and a Müller glia cell subpopulation. In human lymph node data, MarsGT detects an intermediate B cell population potentially acting as lymphoma precursors. In human melanoma data, it identifies a rare MAIT-like population impacted by a high IFN-I response and reveals the mechanism of immunotherapy. Hence, MarsGT offers biological insights and suggests potential strategies for early detection and therapeutic intervention of disease.
Topics: Humans; Animals; Mice; Multiomics; B-Lymphocytes; Electric Power Supplies; Ependymoglial Cells; Immunotherapy
PubMed: 38184630
DOI: 10.1038/s41467-023-44570-8 -
Redox Biology Aug 2022The Pentose Phosphate Pathway (PPP), a metabolic offshoot of the glycolytic pathway, provides protective metabolites and molecules essential for cell redox balance and...
The Pentose Phosphate Pathway (PPP), a metabolic offshoot of the glycolytic pathway, provides protective metabolites and molecules essential for cell redox balance and survival. Transketolase (TKT) is the critical enzyme that controls the extent of "traffic flow" through the PPP. Here, we explored the role of TKT in maintaining the health of the human retina. We found that Müller cells were the primary retinal cell type expressing TKT in the human retina. We further explored the role of TKT in human Müller cells by knocking down its expression in primary cultured Müller cells (huPMCs), isolated from the human retina (11 human donors in total), under light-induced oxidative stress. TKT knockdown and light stress reduced TKT enzymatic activities and the overall metabolic activities of huPMCs with no detectable cell death. TKT knockdown restrained the PPP traffic flow, reduced the expression of NAD(P)H Quinone Dehydrogenase 1 (NQO1), impaired the antioxidative response of NRF2 to light stress and aggravated the endoplasmic reticulum (ER) stress. TKT knockdown also inhibited overall glucose intake, reduced expression of Dihydrolipoamide dehydrogenase (DLD) and impaired the energy supply of the huPMCs. In summary, Müller cell-mediated TKT activity plays a critical protective role in the stressed retina. Knockdown of TKT disrupted the PPP and impaired overall glucose utilisation by huPMCs and rendered huPMCs more vulnerable to light stress by impairing energy supply and antioxidative NRF2 responses.
Topics: Ependymoglial Cells; Glucose; Humans; NF-E2-Related Factor 2; Pentose Phosphate Pathway; Pentoses; Phosphates; Transketolase
PubMed: 35779441
DOI: 10.1016/j.redox.2022.102379