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1.
Nat Commun ; 11(1): 4435, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895385

RESUMO

Colonial ascidians are the only chordates able to undergo whole body regeneration (WBR), during which entire new bodies can be regenerated from small fragments of blood vessels. Here, we show that during the early stages of WBR in Botrylloides diegensis, proliferation occurs only in small, blood-borne cells that express integrin-alpha-6 (IA6), pou3 and vasa. WBR cannot proceed when proliferating IA6+ cells are ablated with Mitomycin C, and injection of a single IA6+ Candidate stem cell can rescue WBR after ablation. Lineage tracing using EdU-labeling demonstrates that donor-derived IA6+ Candidate stem cells directly give rise to regenerating tissues. Inhibitors of either Notch or canonical Wnt signaling block WBR and reduce proliferation of IA6+ Candidate stem cells, indicating that these two pathways regulate their activation. In conclusion, we show that IA6+ Candidate stem cells are responsible for whole body regeneration and give rise to regenerating tissues.


Assuntos
Integrina alfa6/metabolismo , Regeneração/fisiologia , Urocordados , Animais , Cordados não Vertebrados/embriologia , Expressão Gênica , Integrina alfa6/genética , Células-Tronco/citologia , Células-Tronco/metabolismo , Urocordados/citologia , Urocordados/embriologia , Urocordados/crescimento & desenvolvimento
2.
Nat Commun ; 11(1): 4681, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32943626

RESUMO

Although advanced lipidomics technology facilitates quantitation of intracellular lipid components, little is known about the regulation of lipid metabolism in cancer cells. Here, we show that disruption of the Gdpd3 gene encoding a lysophospholipase D enzyme significantly decreased self-renewal capacity in murine chronic myelogenous leukaemia (CML) stem cells in vivo. Sophisticated lipidomics analyses revealed that Gdpd3 deficiency reduced levels of certain lysophosphatidic acids (LPAs) and lipid mediators in CML cells. Loss of Gdpd3 also activated AKT/mTORC1 signalling and cell cycle progression while suppressing Foxo3a/ß-catenin interaction within CML stem cell nuclei. Strikingly, CML stem cells carrying a hypomorphic mutation of Lgr4/Gpr48, which encodes a leucine-rich repeat (LRR)-containing G-protein coupled receptor (GPCR) acting downstream of Gdpd3, displayed inadequate disease-initiating capacity in vivo. Our data showing that lysophospholipid metabolism is required for CML stem cell maintenance in vivo establish a new, biologically significant mechanism of cancer recurrence that is independent of oncogene addiction.


Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Células-Tronco/metabolismo , Animais , Modelos Animais de Doenças , Feminino , Proteína Forkhead Box O3/metabolismo , Lisofosfolipídeos/metabolismo , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Recidiva Local de Neoplasia/metabolismo , Diester Fosfórico Hidrolases/genética , Receptores Acoplados a Proteínas-G/genética , Transdução de Sinais , beta Catenina/metabolismo
3.
Cell Prolif ; 53(10): e12912, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32964544

RESUMO

OBJECTIVES: Mechanical force plays an important role in modulating stem cell fate and behaviours. However, how periodontal ligament stem cells (PDLSCs) perceive mechanical stimulus and transfer it into biological signals, and thereby promote alveolar bone remodelling, is unclear. MATERIALS AND METHODS: An animal model of force-induced tooth movement and a compressive force in vitro was used. After force application, tooth movement distance, mesenchymal stem cell and osteoclast number, and proinflammatory cytokine expression were detected in periodontal tissues. Then, rat primary PDLSCs with or without force loading were isolated, and their stem cell characteristics including clonogenicity, proliferation, multipotent differentiation and immunoregulatory properties were evaluated. Under compressive force in vitro, the effects of the ERK signalling pathway on PDLSC characteristics were evaluated by Western blotting. RESULTS: Mechanical force in vivo induced PDLSC proliferation, which was accompanied with inflammatory cytokine accumulation, osteoclast differentiation and TRPV4 activation; the force-stimulated PDLSCs showed greater clonogenicity and proliferation, reduced differentiation ability, improved induction of macrophage migration, osteoclast differentiation and proinflammatory factor expression. The biological changes induced by mechanical force could be partially suppressed by TRPV4 inhibition. Mechanistically, force-induced activation of TRPV4 in PDLSCs regulated osteoclast differentiation by affecting the RANKL/OPG system via ERK signalling. CONCLUSIONS: Taken together, we show here that TRPV4 activation in PDLSCs under mechanical force contributes to changing their stem cell characteristics and modulates bone remodelling during tooth movement.


Assuntos
Remodelação Óssea , Ligamento Periodontal/citologia , Células-Tronco/citologia , Canais de Cátion TRPV/metabolismo , Animais , Fenômenos Biomecânicos , Proliferação de Células , Células Cultivadas , Humanos , Masculino , Osteoclastos/citologia , Osteoclastos/metabolismo , Ligamento Periodontal/metabolismo , Ratos , Ratos Sprague-Dawley , Células-Tronco/metabolismo , Estresse Mecânico
4.
Ecotoxicol Environ Saf ; 205: 111283, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32977282

RESUMO

Fine particulate matter (PM2.5) airborne pollution increases the risk of chronic respiratory diseases, such as idiopathic pulmonary fibrosis (IPF), which is characterized by non-specific inflammation of the interstitial lung and extensive deposition of collagen fibers. Type 2 alveolar epithelial cells (AEC2s) are alveolar stem cells in the adult lung that contribute to the lung repair process through complex signaling. Our previous studies demonstrated that OGG1, a kind of DNA repair enzyme, have a critical role in protecting cells from oxidative damage and apoptosis induced by PM2.5, but the contribution of OGG1 in proliferation and self-renewal of AEC2s is not known. Here, we constructed OGG1-/-mice to test the effect and mechanism of OGG1 on PM2.5-induced pulmonary fibrosis and injury in vivo. We detected proliferation and self-renewal of OGG1 overexpression or OGG1 knockout AEC2s after PM2.5 injury by flow cytometry and clone formation. We observed that knockout of OGG1 aggravated pulmonary fibrosis, oxidative stress, and AEC2 cell death in PM2.5-injured mice. In addition, OGG1 is required for the proliferation and renewal of AEC2s after PM2.5 injury. Overexpression of OGG1 promotes the proliferation and self-renewal of AEC2s by inhibiting PM2.5-mediated oxidative stress and NF-κB signaling hyperactivation in vitro. Furthermore, NF-κB inhibitors promoted proliferation and self-renewal of OGG1-deficient AEC2s cells after PM2.5 injury, and attenuated PM2.5-induced pulmonary fibrosis and injury in mice. These data establish OGG1 as a regulator of NF-κB signal that serves to regulate AEC2 cell proliferation and self-renewal, and suggest a mechanism that inhibition of the NF-κB signaling pathway may represent a potential therapeutic strategy for IPF patients with low-expression of OGG1.


Assuntos
Poluentes Atmosféricos/toxicidade , Células Epiteliais Alveolares/efeitos dos fármacos , Autorrenovação Celular/genética , DNA Glicosilases/metabolismo , Material Particulado/toxicidade , Fibrose Pulmonar/induzido quimicamente , Células-Tronco/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/patologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , DNA Glicosilases/genética , Humanos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Fibrose Pulmonar/genética , Fibrose Pulmonar/patologia , Transdução de Sinais , Células-Tronco/metabolismo , Células-Tronco/patologia
5.
PLoS One ; 15(8): e0235898, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833999

RESUMO

Myo/Nog cells were discovered in the chick embryo epiblast. Their expression of MyoD reflects a commitment to the skeletal muscle lineage and capacity to differentiate into myofibroblasts. Release of Noggin by Myo/Nog cells is essential for normal morphogenesis. Myo/Nog cells rapidly respond to wounding in the skin and eyes. In this report, we present evidence suggesting that Myo/Nog cells phagocytose tattoo ink in tissue sections of human skin and engulf cell corpses in cultures of anterior human lens tissue and magnetic beads injected into the anterior chamber of mice in vivo. Myo/Nog cells are distinct from macrophages in the skin and eyes indicated by the absence of labeling with an antibody to ionized calcium binding adaptor molecule 1. In addition to their primary roles as regulators of BMP signaling and progenitors of myofibroblasts, Myo/Nog cells behave as nonprofessional phagocytes defined as cells whose primary functions are unrelated to phagocytosis but are capable of engulfment.


Assuntos
Miofibroblastos/citologia , Fagócitos/citologia , Células-Tronco/citologia , Animais , Proteínas de Transporte/metabolismo , Diferenciação Celular , Células Cultivadas , Embrião de Galinha , Feminino , Humanos , Cristalino/citologia , Cristalino/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteína MyoD/metabolismo , Miofibroblastos/metabolismo , Fagócitos/metabolismo , Fagocitose , Coelhos , Pele/citologia , Pele/metabolismo , Células-Tronco/metabolismo
6.
PLoS One ; 15(8): e0237773, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822378

RESUMO

Microglial cells play a key role in brain homeostasis from development to adulthood. Here we show the involvement of a site-specific phosphorylation of Presenilin 1 (PS1) in microglial development. Profiles of microglia-specific transcripts in different temporal stages of development, combined with multiple systematic transcriptomic analysis and quantitative determination of microglia progenitors, indicate that the phosphorylation of PS1 at serine 367 is involved in the temporal dynamics of microglial development, specifically in the developing brain rudiment during embryonic microgliogenesis. We constructed a developing brain-specific microglial network to identify transcription factors linked to PS1 during development. Our data showed that PS1 functional connections appear through interaction hubs at Pu.1, Irf8 and Rela-p65 transcription factors. Finally, we showed that the total number of microglia progenitors was markedly reduced in the developing brain rudiment of embryos lacking PS1 phosphorylation compared to WT. Our work identifies a novel role for PS1 in microglial development.


Assuntos
Redes Reguladoras de Genes , Microglia/fisiologia , Presenilina-1/metabolismo , Células-Tronco/metabolismo , Animais , Encéfalo/embriologia , Encéfalo/metabolismo , Feminino , Masculino , Camundongos Endogâmicos C57BL , Fosforilação , Presenilina-1/genética , Células-Tronco/citologia , Transcriptoma
7.
Nat Commun ; 11(1): 4239, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843640

RESUMO

How stem cells give rise to epidermis is unclear despite the crucial role the epidermis plays in barrier and appendage formation. Here we use single cell-RNA sequencing to interrogate basal stem cell heterogeneity of human interfollicular epidermis and find four spatially distinct stem cell populations at the top and bottom of rete ridges and transitional positions between the basal and suprabasal epidermal layers. Cell-cell communication modeling suggests that basal cell populations serve as crucial signaling hubs to maintain epidermal communication. Combining pseudotime, RNA velocity, and cellular entropy analyses point to a hierarchical differentiation lineage supporting multi-stem cell interfollicular epidermal homeostasis models and suggest that transitional basal stem cells are stable states essential for proper stratification. Finally, alterations in differentially expressed transitional basal stem cell genes result in severe thinning of human skin equivalents, validating their essential role in epidermal homeostasis and reinforcing the critical nature of basal stem cell heterogeneity.


Assuntos
Diferenciação Celular , Células Epidérmicas/citologia , Homeostase , Células-Tronco/citologia , Comunicação Celular/genética , Diferenciação Celular/genética , Linhagem da Célula/genética , Células Epidérmicas/metabolismo , Epiderme/metabolismo , Prepúcio do Pênis/citologia , Prepúcio do Pênis/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Recém-Nascido , Queratinócitos/citologia , Queratinócitos/metabolismo , Masculino , Modelos Biológicos , Transdução de Sinais , Células-Tronco/metabolismo
8.
Nature ; 584(7821): 415-419, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641829

RESUMO

Sexual dimorphism arises from genetic differences between male and female cells, and from systemic hormonal differences1-3. How sex hormones affect non-reproductive organs is poorly understood, yet highly relevant to health given the sex-biased incidence of many diseases4. Here we report that steroid signalling in Drosophila from the ovaries to the gut promotes growth of the intestine specifically in mated females, and enhances their reproductive output. The active ovaries of the fly produce the steroid hormone ecdysone, which stimulates the division and expansion of intestinal stem cells in two distinct proliferative phases via the steroid receptors EcR and Usp and their downstream targets Broad, Eip75B and Hr3. Although ecdysone-dependent growth of the female gut augments fecundity, the more active and more numerous intestinal stem cells also increase female susceptibility to age-dependent gut dysplasia and tumorigenesis, thus potentially reducing lifespan. This work highlights the trade-offs in fitness traits that occur when inter-organ signalling alters stem-cell behaviour to optimize organ size.


Assuntos
Drosophila melanogaster/metabolismo , Fertilidade/fisiologia , Intestinos/crescimento & desenvolvimento , Longevidade/fisiologia , Tamanho do Órgão/fisiologia , Ovário/metabolismo , Esteroides/metabolismo , Envelhecimento , Animais , Carcinogênese , Proliferação de Células , Copulação/fisiologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/anatomia & histologia , Drosophila melanogaster/citologia , Drosophila melanogaster/fisiologia , Ecdisona/metabolismo , Feminino , Mucosa Intestinal/anatomia & histologia , Mucosa Intestinal/citologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Intestinos/anatomia & histologia , Intestinos/citologia , Intestinos/patologia , Masculino , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Esteroides/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Fatores de Transcrição/metabolismo
9.
Proc Natl Acad Sci U S A ; 117(30): 17796-17807, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32651268

RESUMO

Fluctuation in signal transduction pathways is frequently observed during mammalian development. However, its role in regulating stem cells has not been explored. Here we tracked spatiotemporal ERK MAPK dynamics in human epidermal stem cells. While stem cells and differentiated cells were distinguished by high and low stable basal ERK activity, respectively, we also found cells with pulsatile ERK activity. Transitions from Basalhi-Pulselo (stem) to Basalhi-Pulsehi, Basalmid-Pulsehi, and Basallo-Pulselo (differentiated) cells occurred in expanding keratinocyte colonies and in response to differentiation stimuli. Pharmacological inhibition of ERK induced differentiation only when cells were in the Basalmid-Pulsehi state. Basal ERK activity and pulses were differentially regulated by DUSP10 and DUSP6, leading us to speculate that DUSP6-mediated ERK pulse down-regulation promotes initiation of differentiation, whereas DUSP10-mediated down-regulation of mean ERK activity promotes and stabilizes postcommitment differentiation. Levels of MAPK1/MAPK3 transcripts correlated with DUSP6 and DUSP10 transcripts in individual cells, suggesting that ERK activity is negatively regulated by transcriptional and posttranslational mechanisms. When cells were cultured on a topography that mimics the epidermal-dermal interface, spatial segregation of mean ERK activity and pulses was observed. In vivo imaging of mouse epidermis revealed a patterned distribution of basal cells with pulsatile ERK activity, and down-regulation was linked to the onset of differentiation. Our findings demonstrate that ERK MAPK signal fluctuations link kinase activity to stem cell dynamics.


Assuntos
Diferenciação Celular , Células Epidérmicas/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células-Tronco/metabolismo , Animais , Técnicas de Cultura de Células , Proliferação de Células , Ativação Enzimática , Células Epidérmicas/citologia , Queratinócitos/metabolismo , Mamíferos , Camundongos , Fosfoproteínas Fosfatases/metabolismo , Transdução de Sinais , Células-Tronco/citologia
10.
Proc Natl Acad Sci U S A ; 117(30): 17842-17853, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32669437

RESUMO

Stem cells are capable of unlimited proliferation but can be induced to form brain cells. Factors that specifically regulate human development are poorly understood. We found that human stem cells expressed high levels of the envelope protein of an endogenized human-specific retrovirus (HERV-K, HML-2) from loci in chromosomes 12 and 19. The envelope protein was expressed on the cell membrane of the stem cells and was critical in maintaining the stemness via interactions with CD98HC, leading to triggering of human-specific signaling pathways involving mammalian target of rapamycin (mTOR) and lysophosphatidylcholine acyltransferase (LPCAT1)-mediated epigenetic changes. Down-regulation or epigenetic silencing of HML-2 env resulted in dissociation of the stem cell colonies and enhanced differentiation along neuronal pathways. Thus HML-2 regulation is critical for human embryonic and neurodevelopment, while it's dysregulation may play a role in tumorigenesis and neurodegeneration.


Assuntos
Diferenciação Celular , Retrovirus Endógenos/fisiologia , Neurônios/metabolismo , Transdução de Sinais , Células-Tronco/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Biomarcadores , Diferenciação Celular/genética , Autorrenovação Celular/genética , Cadeia Pesada da Proteína-1 Reguladora de Fusão/metabolismo , Regulação Viral da Expressão Gênica , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurônios/citologia , Ligação Proteica , Células-Tronco/citologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas do Envelope Viral/genética
11.
Nat Commun ; 11(1): 3559, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678092

RESUMO

The cell type specific sequences of transcriptional programs during lung regeneration have remained elusive. Using time-series single cell RNA-seq of the bleomycin lung injury model, we resolved transcriptional dynamics for 28 cell types. Trajectory modeling together with lineage tracing revealed that airway and alveolar stem cells converge on a unique Krt8 + transitional stem cell state during alveolar regeneration. These cells have squamous morphology, feature p53 and NFkB activation and display transcriptional features of cellular senescence. The Krt8+ state appears in several independent models of lung injury and persists in human lung fibrosis, creating a distinct cell-cell communication network with mesenchyme and macrophages during repair. We generated a model of gene regulatory programs leading to Krt8+ transitional cells and their terminal differentiation to alveolar type-1 cells. We propose that in lung fibrosis, perturbed molecular checkpoints on the way to terminal differentiation can cause aberrant persistence of regenerative intermediate stem cell states.


Assuntos
Células Epiteliais Alveolares/metabolismo , Queratina-8/metabolismo , Alvéolos Pulmonares/fisiologia , Fibrose Pulmonar/patologia , Regeneração , Células-Tronco/metabolismo , Células Epiteliais Alveolares/citologia , Animais , Comunicação Celular , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Humanos , Queratina-8/genética , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/metabolismo , Lesão Pulmonar/patologia , Camundongos , Camundongos Endogâmicos C57BL , Alvéolos Pulmonares/citologia , Fibrose Pulmonar/metabolismo , Análise de Célula Única , Células-Tronco/citologia
12.
Proc Natl Acad Sci U S A ; 117(32): 19276-19286, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32719141

RESUMO

Bone homeostasis requires continuous remodeling of bone matrix to maintain structural integrity. This involves extensive communication between bone-forming osteoblasts and bone-resorbing osteoclasts to orchestrate balanced progenitor cell recruitment and activation. Only a few mediators controlling progenitor activation are known to date and have been targeted for intervention of bone disorders such as osteoporosis. To identify druggable pathways, we generated a medaka (Oryzias latipes) osteoporosis model, where inducible expression of receptor-activator of nuclear factor kappa-Β ligand (Rankl) leads to ectopic formation of osteoclasts and excessive bone resorption, which can be assessed by live imaging. Here we show that upon Rankl induction, osteoblast progenitors up-regulate expression of the chemokine ligand Cxcl9l. Ectopic expression of Cxcl9l recruits mpeg1-positive macrophages to bone matrix and triggers their differentiation into osteoclasts. We also demonstrate that the chemokine receptor Cxcr3.2 is expressed in a distinct subset of macrophages in the aorta-gonad-mesonephros (AGM). Live imaging revealed that upon Rankl induction, Cxcr3.2-positive macrophages get activated, migrate to bone matrix, and differentiate into osteoclasts. Importantly, mutations in cxcr3.2 prevent macrophage recruitment and osteoclast differentiation. Furthermore, Cxcr3.2 inhibition by the chemical antagonists AMG487 and NBI-74330 also reduced osteoclast recruitment and protected bone integrity against osteoporotic insult. Our data identify a mechanism for progenitor recruitment to bone resorption sites and Cxcl9l and Cxcr3.2 as potential druggable regulators of bone homeostasis and osteoporosis.


Assuntos
Matriz Óssea/metabolismo , Quimiocina CXCL9/metabolismo , Proteínas de Peixes/metabolismo , Oryzias/metabolismo , Osteoclastos/metabolismo , Osteoporose/metabolismo , Receptores CXCR3/metabolismo , Células-Tronco/metabolismo , Animais , Matriz Óssea/crescimento & desenvolvimento , Diferenciação Celular , Quimiocina CXCL9/genética , Modelos Animais de Doenças , Proteínas de Peixes/genética , Humanos , Macrófagos/metabolismo , Oryzias/genética , Oryzias/crescimento & desenvolvimento , Osteoblastos/citologia , Osteoblastos/metabolismo , Osteoclastos/citologia , Osteoporose/genética , Osteoporose/fisiopatologia , Ligação Proteica , Receptores CXCR3/genética , Células-Tronco/citologia
13.
Proc Natl Acad Sci U S A ; 117(32): 19287-19298, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32723825

RESUMO

Retinal ganglion cell axons forming the optic nerve (ON) emerge unmyelinated from the eye and become myelinated after passage through the optic nerve lamina region (ONLR), a transitional area containing a vascular plexus. The ONLR has a number of unusual characteristics: it inhibits intraocular myelination, enables postnatal ON myelination of growing axons, modulates the fluid pressure differences between eye and brain, and is the primary lesion site in the age-related disease open angle glaucoma (OAG). We demonstrate that the human and rodent ONLR possesses a mitotically active, age-depletable neural progenitor cell (NPC) niche, with unique characteristics and culture requirements. These NPCs generate both forms of macroglia: astrocytes and oligodendrocytes, and can form neurospheres in culture. Using reporter mice with SOX2-driven, inducible gene expression, we show that ONLR-NPCs generate macroglial cells for the anterior ON. Early ONLR-NPC loss results in regional dysfunction and hypomyelination. In adulthood, ONLR-NPCs may enable glial replacement and remyelination. ONLR-NPC depletion may help explain why ON diseases such as OAG progress in severity during aging.


Assuntos
Neurônios/citologia , Nervo Óptico/citologia , Nicho de Células-Tronco , Células-Tronco/citologia , Animais , Astrócitos , Axônios/metabolismo , Diferenciação Celular , Glaucoma de Ângulo Aberto/genética , Glaucoma de Ângulo Aberto/metabolismo , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos , Camundongos , Bainha de Mielina/metabolismo , Neuroglia , Neurônios/metabolismo , Oligodendroglia , Nervo Óptico/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Células-Tronco/metabolismo
14.
Nat Cell Biol ; 22(8): 919-926, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32690888

RESUMO

Intestinal stem cells (ISCs) are located at the crypt base and fine-tune the balance of their self-renewal and differentiation1,2, but the physiological mechanism involved in regulating that balance remains unknown. Here we describe a transcriptional regulator that preserves the stemness of ISCs by restricting their differentiation into secretory-cell lineages. Interferon regulatory factor 2 (IRF2) negatively regulates interferon signalling3, and mice completely lacking Irf24 or with a selective Irf2 deletion in their intestinal epithelial cells have significantly fewer crypt Lgr5hi ISCs than control mice. Although the integrity of intestinal epithelial cells was unimpaired at steady state in Irf2-deficient mice, regeneration of their intestinal epithelia after 5-fluorouracil-induced damage was severely impaired. Similarly, extended treatment with low-dose poly(I:C) or chronic infection of lymphocytic choriomeningitis virus clone 13 (LCMV C13)5 caused a functional decline of ISCs in wild-type mice. In contrast, massive accumulations of immature Paneth cells were found at the crypt base of Irf2-/- as well as LCMV C13-infected wild-type mice, indicating that excess interferon signalling directs ISCs towards a secretory-cell fate. Collectively, our findings indicate that regulated interferon signalling preserves ISC stemness by restricting secretory-cell differentiation.


Assuntos
Linhagem da Célula , Fator Regulador 2 de Interferon/metabolismo , Mucosa Intestinal/citologia , Transdução de Sinais , Células-Tronco/metabolismo , Idoso , Animais , Diferenciação Celular/genética , Linhagem da Célula/genética , Feminino , Regulação da Expressão Gênica , Humanos , Interferons/metabolismo , Mucosa Intestinal/metabolismo , Secreções Intestinais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Células-Tronco/citologia
15.
Nature ; 584(7820): 268-273, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32728211

RESUMO

The ability of the skin to grow in response to stretching has been exploited in reconstructive surgery1. Although the response of epidermal cells to stretching has been studied in vitro2,3, it remains unclear how mechanical forces affect their behaviour in vivo. Here we develop a mouse model in which the consequences of stretching on skin epidermis can be studied at single-cell resolution. Using a multidisciplinary approach that combines clonal analysis with quantitative modelling and single-cell RNA sequencing, we show that stretching induces skin expansion by creating a transient bias in the renewal activity of epidermal stem cells, while a second subpopulation of basal progenitors remains committed to differentiation. Transcriptional and chromatin profiling identifies how cell states and gene-regulatory networks are modulated by stretching. Using pharmacological inhibitors and mouse mutants, we define the step-by-step mechanisms that control stretch-mediated tissue expansion at single-cell resolution in vivo.


Assuntos
Mecanotransdução Celular/fisiologia , Análise de Célula Única , Pele/citologia , Pele/crescimento & desenvolvimento , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Junções Aderentes/metabolismo , Animais , Sequência de Bases , Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular/efeitos dos fármacos , Autorrenovação Celular/efeitos dos fármacos , Cromatina/efeitos dos fármacos , Cromatina/genética , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Células Clonais/citologia , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Modelos Animais de Doenças , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Redes Reguladoras de Genes/efeitos dos fármacos , Hidrogéis/administração & dosagem , Hidrogéis/farmacologia , Mecanotransdução Celular/efeitos dos fármacos , Mecanotransdução Celular/genética , Camundongos , Camundongos Transgênicos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação , RNA Mensageiro/genética , RNA-Seq , Pele/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Transativadores/antagonistas & inibidores , Transativadores/metabolismo , Fator de Transcrição AP-1/metabolismo , Transcrição Genética/efeitos dos fármacos
16.
PLoS One ; 15(7): e0236519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730297

RESUMO

Stem cells, with their capacity to self-renew and to differentiate to more specialized cell types, play a key role to maintain homeostasis in adult tissues. To investigate how, in the dynamic stochastic environment of a tissue, non-genetic diversity and the precise balance between proliferation and differentiation are achieved, it is necessary to understand the molecular mechanisms of the stem cells in decision making process. By focusing on the impact of stochasticity, we proposed a computational model describing the regulatory circuitry as a tri-stable dynamical system to reveal the mechanism which orchestrate this balance. Our model explains how the distribution of noise in genes, linked to the cell regulatory networks, affects cell decision-making to maintain homeostatic state. The noise effect on tissue homeostasis is achieved by regulating the probability of differentiation and self-renewal through symmetric and/or asymmetric cell divisions. Our model reveals, when mutations due to the replication of DNA in stem cell division, are inevitable, how mutations contribute to either aging gradually or the development of cancer in a short period of time. Furthermore, our model sheds some light on the impact of more complex regulatory networks on the system robustness against perturbations.


Assuntos
Modelos Biológicos , Células-Tronco/metabolismo , Animais , Diferenciação Celular , Autorrenovação Celular , Humanos , Células-Tronco/citologia
17.
Proc Natl Acad Sci U S A ; 117(24): 13562-13570, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482863

RESUMO

Various pregnancy complications, such as severe forms of preeclampsia or intrauterine growth restriction, are thought to arise from failures in the differentiation of human placental trophoblasts. Progenitors of the latter either develop into invasive extravillous trophoblasts, remodeling the uterine vasculature, or fuse into multinuclear syncytiotrophoblasts transporting oxygen and nutrients to the growing fetus. However, key regulatory factors controlling trophoblast self-renewal and differentiation have been poorly elucidated. Using primary cells, three-dimensional organoids, and CRISPR-Cas9 genome-edited JEG-3 clones, we herein show that YAP, the transcriptional coactivator of the Hippo signaling pathway, promotes maintenance of cytotrophoblast progenitors by different genomic mechanisms. Genetic or chemical manipulation of YAP in these cellular models revealed that it stimulates proliferation and expression of cell cycle regulators and stemness-associated genes, but inhibits cell fusion and production of syncytiotrophoblast (STB)-specific proteins, such as hCG and GDF15. Genome-wide comparisons of primary villous cytotrophoblasts overexpressing constitutively active YAP-5SA with YAP KO cells and syncytializing trophoblasts revealed common target genes involved in trophoblast stemness and differentiation. ChIP-qPCR unraveled that YAP-5SA overexpression increased binding of YAP-TEAD4 complexes to promoters of proliferation-associated genes such as CCNA and CDK6 Moreover, repressive YAP-TEAD4 complexes containing the histone methyltransferase EZH2 were detected in the genomic regions of the STB-specific CGB5 and CGB7 genes. In summary, YAP plays a pivotal role in the maintenance of the human placental trophoblast epithelium. Besides activating stemness factors, it also directly represses genes promoting trophoblast cell fusion.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Placentação , Fatores de Transcrição/metabolismo , Trofoblastos/citologia , Trofoblastos/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Diferenciação Celular , Proliferação de Células , Quinase 6 Dependente de Ciclina/genética , Quinase 6 Dependente de Ciclina/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Humanos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Placenta/metabolismo , Gravidez , Ligação Proteica , Transdução de Sinais , Células-Tronco/citologia , Células-Tronco/metabolismo , Fatores de Transcrição/genética
18.
Int J Oral Sci ; 12(1): 18, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32555173

RESUMO

Once pulp necrosis or apical periodontitis occurs on immature teeth, the weak root and open root apex are challenging to clinicians. Berberine (BBR) is a potential medicine for bone disorders, therefore, we proposed to apply BBR in root canals to enhance root repair in immature teeth. An in vivo model of immature teeth with apical periodontitis was established in rats, and root canals were filled with BBR, calcium hydroxide or sterilized saline for 3 weeks. The shape of the roots was analyzed by micro-computed tomography and histological staining. In vitro, BBR was introduced into stem cells from apical papilla (SCAPs). Osteogenic differentiation of stem cells from apical papilla was investigated by alkaline phosphatase activity, mineralization ability, and gene expression of osteogenic makers. The signaling pathway, which regulated the osteogenesis of SCAPs was evaluated by quantitative real time PCR, Western blot analysis, and immunofluorescence. In rats treated with BBR, more tissue was formed, with longer roots, thicker root walls, and smaller apex diameters. In addition, we found that BBR promoted SCAPs osteogenesis in a time-dependent and concentration-dependent manner. BBR induced the expression of ß-catenin and enhanced ß-catenin entering into the nucleus, to up-regulate more runt-related nuclear factor 2 downstream. BBR enhanced root repair in immature teeth with apical periodontitis by activating the canonical Wnt/ß-catenin pathway in SCAPs.


Assuntos
Berberina/farmacologia , Osteogênese/efeitos dos fármacos , Periodontite Periapical/terapia , Células-Tronco/efeitos dos fármacos , Via de Sinalização Wnt/efeitos dos fármacos , Animais , Diferenciação Celular/efeitos dos fármacos , Papila Dentária , Masculino , Ratos , Células-Tronco/citologia , Células-Tronco/metabolismo , Proteína Wnt3A/genética , Proteína Wnt3A/metabolismo , Microtomografia por Raio-X
19.
Nat Commun ; 11(1): 2797, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493999

RESUMO

Fat distribution is an independent cardiometabolic risk factor. However, its molecular and cellular underpinnings remain obscure. Here we demonstrate that two independent GWAS signals at RSPO3, which are associated with increased body mass index-adjusted waist-to-hip ratio, act to specifically increase RSPO3 expression in subcutaneous adipocytes. These variants are also associated with reduced lower-body fat, enlarged gluteal adipocytes and insulin resistance. Based on human cellular studies RSPO3 may limit gluteofemoral adipose tissue (AT) expansion by suppressing adipogenesis and increasing gluteal adipocyte susceptibility to apoptosis. RSPO3 may also promote upper-body fat distribution by stimulating abdominal adipose progenitor (AP) proliferation. The distinct biological responses elicited by RSPO3 in abdominal versus gluteal APs in vitro are associated with differential changes in WNT signalling. Zebrafish carrying a nonsense rspo3 mutation display altered fat distribution. Our study identifies RSPO3 as an important determinant of peripheral AT storage capacity.


Assuntos
Adipócitos/citologia , Adipócitos/metabolismo , Distribuição da Gordura Corporal , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Trombospondinas/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Adipócitos/efeitos dos fármacos , Tecido Adiposo/metabolismo , Adiposidade/genética , Adulto , Alelos , Animais , Biomarcadores/metabolismo , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Tamanho Celular/efeitos dos fármacos , Doxiciclina/farmacologia , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Pessoa de Meia-Idade , Mutação/genética , Polimorfismo de Nucleotídeo Único/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Caracteres Sexuais , Células-Tronco/metabolismo , Trombospondinas/genética , Relação Cintura-Quadril , Via de Sinalização Wnt/efeitos dos fármacos , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
20.
PLoS One ; 15(6): e0234002, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497071

RESUMO

Human primary hepatocytes (PHs) are critical to studying liver functions, drug metabolism and toxicity. PHs isolated from livers that are unacceptable for transplantation have limited expansion and culture viability in vitro, in addition to rapidly deteriorating enzymatic functions. The unsuitability of immortalized hepato-carcinoma cell lines for this function has prompted studies to develop hepatocyte-like cells from alternative sources like ESC, iPS, and other stem cell types using differentiation protocols. This study describes a novel technique to produce expandable and functional hepatocyte-like cells from the fusion of an immortalized human umbilical cord blood derived cell line (E12 MLPC) to normal human primary hepatocytes. Multi-lineage progenitor cells (MLPC) comprise a small subset of mesenchymal-like cells isolated from human umbilical cord blood. MLPC are distinguishable from other mesenchymal-like cells by their extended expansion capacity (up to 80 cell doublings before senescence) and the ability to be differentiated into cells representative of endo-, meso- and ectodermal origins. Transfection of MLPC with the gene for telomerase reverse transcriptase (TERT) resulted in clonal cell lines that were capable of differentiation to different cellular outcomes while maintaining their functional immortality. A methodology for the development of immortalized hepatocyte-like hybrid cells by the in vitro fusion of human MLPC with normal human primary hepatocytes is reported. The resultant hybrid cells exhibited homology with hepatocytes by morphology, immunohistochemistry, urea and albumin production and gene expression. A medium that allows stable long-term expansion of hepatocyte-like fusion cells is described.


Assuntos
Fusão Celular , Hepatócitos/citologia , Células Híbridas/citologia , Células-Tronco/citologia , Diferenciação Celular , Células Cultivadas , Hepatócitos/metabolismo , Humanos , Células Híbridas/metabolismo , Células-Tronco/metabolismo , Telomerase/genética , Transfecção
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