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1.
Dev Biol ; 481: 14-29, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34543654

RESUMO

Environmental teratogens such as smoking are known risk factors for developmental disorders such as cleft palate. While smoking rates have declined, a new type of smoking, called vaping is on the rise. Vaping is the use of e-cigarettes to vaporize and inhale an e-liquid containing nicotine and food-like flavors. There is the potential that, like smoking, vaping could also pose a danger to the developing human. Rather than waiting for epidemiological and mammalian studies, we have turned to an aquatic developmental model, Xenopus laevis, to more quickly assess whether e-liquids contain teratogens that could lead to craniofacial malformations. Xenopus, like zebrafish, has the benefit of being a well-established developmental model and has also been effective in predicting whether a chemical could be a teratogen. We have determined that embryonic exposure to dessert flavored e-liquids can cause craniofacial abnormalities, including an orofacial cleft in Xenopus. To better understand the underlying mechanisms contributing to these defects, transcriptomic analysis of the facial tissues of embryos exposed to a representative dessert flavored e-liquid vapor extract was performed. Analysis of differentially expressed genes in these embryos revealed several genes associated with retinoic acid metabolism or the signaling pathway. Consistently, retinoic acid receptor inhibition phenocopied the craniofacial defects as those embryos exposed to the vapor extract of the e-liquid. Such malformations also correlated with a group of common differentially expressed genes, two of which are associated with midface birth defects in humans. Further, e-liquid exposure sensitized embryos to forming craniofacial malformations when they already had depressed retinoic acid signaling. Moreover, 13-cis-retinoic acid treatment could significantly reduce the e-liquid induced malformation in the midface. Such results suggest the possibility of an interaction between retinoic acid signaling and e-liquid exposure. One of the most popular and concentrated flavoring chemicals in dessert flavored e-liquids is vanillin. Xenopus embryos exposed to this chemical closely resembled embryos exposed to dessert-like e-liquids and a retinoic acid receptor antagonist. In summary, we determined that e-liquid chemicals, in particular vanillin, can cause craniofacial defects potentially by dysregulating retinoic acid signaling. This work warrants the evaluation of vanillin and other such flavoring additives in e-liquids on mammalian development.


Assuntos
Benzaldeídos/administração & dosagem , Anormalidades Craniofaciais , Embrião não Mamífero/embriologia , Aromatizantes/efeitos adversos , Transdução de Sinais/efeitos dos fármacos , Produtos do Tabaco/toxicidade , Tretinoína/metabolismo , Animais , Benzaldeídos/farmacologia , Anormalidades Craniofaciais/induzido quimicamente , Anormalidades Craniofaciais/embriologia , Embrião não Mamífero/patologia , Aromatizantes/farmacologia , Xenopus laevis
2.
Dev Biol ; 481: 160-171, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34666023

RESUMO

The corpuscles of Stannius (CS) represent a unique endocrine organ of teleostean fish that secrets stanniocalcin-1 (Stc1) to maintain calcium homeostasis. Appearing at 20-25 somite stage in the distal zebrafish pronephros, stc1-expressing cells undergo apical constriction, and are subsequently extruded to form a distinct gland on top of the distal pronephric tubules at 50 â€‹h post fertilization (hpf). Several transcription factors (e.g. Hnf1b, Irx3b, Tbx2a/b) and signaling pathways (e.g. Notch) control CS development. We report now that Fgf signaling is required to commit tubular epithelial cells to differentiate into stc1-expressing CS cells. Inhibition of Fgf signaling by SU5402, dominant-negative Fgfr1, or depletion of fgf8a prevented CS formation and stc1 expression. Ablation experiments revealed that CS have the ability to partially regenerate via active cell migration involving extensive filopodia and lamellipodia formation. Activation of Wnt signaling curtailed stc1 expression, but had no effect on CS formation. Thus, our observations identify Fgf signaling as a crucial component of CS cell fate commitment.


Assuntos
Diferenciação Celular , Glândulas Endócrinas/embriologia , Fatores de Crescimento de Fibroblastos , Pronefro/embriologia , Via de Sinalização Wnt , Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
3.
Dev Biol ; 481: 129-138, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34688689

RESUMO

Development is often driven by signaling and lineage-specific cues, yielding highly uniform and reproducible outcomes. Development also involves mechanisms that generate noise in gene expression and random patterns across tissues. Cells sometimes randomly choose between two or more cell fates in a mechanism called stochastic cell fate specification. This process diversifies cell types in otherwise homogenous tissues. Stochastic mechanisms have been extensively studied in prokaryotes where noisy gene activation plays a pivotal role in controlling cell fates. In eukaryotes, transcriptional repression stochastically limits gene expression to generate random patterns and specify cell fates. Here, we review our current understanding of repressive mechanisms that produce random patterns of gene expression and cell fates in flies, plants, mice, and humans.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Plantas , Transcrição Genética , Animais , Humanos , Camundongos , Plantas/embriologia , Plantas/genética
4.
Life Sci ; 289: 120244, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34922940

RESUMO

AIMS: A new polypeptide, PDTLN1, derived from the human Talin-1 protein, which is highly expressed in both myocardial tissue and maternal peripheral blood of aborted fetuses with congenital heart disease (CHD). However, its role in cardiac developmental disorders has not been disclosed till now. In the present study, we aim to assess the functions of PDTLN1 in heart development of zebrafish and cellular viability, proliferation, and apoptosis of P19 cells. MAIN METHODS: Cellular viability was assessed by Cell Counting Kit-8, the EdU Kit was used to evaluate cellular proliferation, and apoptosic rate of P19 was examined using FITC Annexin-V staining followed by flow cytometry. The zebrafish embryos were divided into three groups: PEP group and NC group were microinjected with polypeptides, WT group without any intervention. The protein expression of PI3K/AKT were evaluated by western blotting. KEY FINDINGS: PDTLN1 could suppress the proliferation, and facilitate apoptosis. PDTLN1 caused abnormal heart development of zebrafish embryos and the PDTLN1 (50 µM)-injected group showed an aberrant expression pattern of vmhc, amhc and cmlc2. Compared to the CTL group and SC79 group of P19 cells, the PDTLN1 group had a lower phosphorylated PI3K/AKT proteins level, decreased cellular viability and lower proliferation activity. SIGNIFICANCE: PDTLN1 caused cardiac developmental defects in zebrafish, inhibited cellular viability, proliferation, and promoted apoptosis of P19 cells via suppressing the PI3K/AKT signaling pathway. Our findings provide a fresh perspective on the functional mechanism of human-derived peptides and may promote novel diagnostic biomarkers detection and therapeutic targets in CHD.


Assuntos
Apoptose/efeitos dos fármacos , Cardiopatias , Peptídeos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Talina/química , Proteínas de Peixe-Zebra/metabolismo , Animais , Linhagem Celular , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Cardiopatias/induzido quimicamente , Cardiopatias/embriologia , Humanos , Peptídeos/efeitos adversos , Peptídeos/química , Peptídeos/farmacologia , Peixe-Zebra
5.
Environ Pollut ; 294: 118646, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34896224

RESUMO

With the rapidly increasing popularity of 5G mobile technology, the effect of radiofrequency radiation on human health has caused public concern. This study explores the effects of a simulated 3.5 GHz radiofrequency electromagnetic radiation (RF-EMF) environment on the development and microbiome of flies under intensities of 0.1 W/m2, 1 W/m2 and 10 W/m2. We found that the pupation percentages in the first 3 days and eclosion rate in the first 2 days were increased under exposure to RF-EMF, and the mean development time was shortened. In a study on third-instar larvae, the expression levels of the heat shock protein genes hsp22, hsp26 and hsp70 and humoral immune system genes AttC, TotC and TotA were all significantly increased. In the oxidative stress system, DuoX gene expression was decreased, sod2 and cat gene expression levels were increased, and SOD and CAT enzyme activity also showed a significant increase. According to the 16S rDNA results, the diversity and species abundance of the microbial community decreased significantly, and according to the functional prediction analysis, the genera Acetobacter and Lactobacillus were significantly increased. In conclusion, 3.5 GHz RF-EMF may enhance thermal stress, oxidative stress and humoral immunity, cause changes in the microbial community, and regulate the insulin/TOR and ecdysteroid signalling pathways to promote fly development.


Assuntos
Drosophila melanogaster , Campos Eletromagnéticos , Microbiota/efeitos da radiação , Ondas de Rádio , Animais , Telefone Celular , Drosophila melanogaster/embriologia , Drosophila melanogaster/microbiologia , Drosophila melanogaster/efeitos da radiação , Expressão Gênica , Proteínas de Choque Térmico , Larva/efeitos da radiação
6.
Cell ; 184(26): 6313-6325.e18, 2021 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-34942099

RESUMO

How tissues acquire complex shapes is a fundamental question in biology and regenerative medicine. Zebrafish semicircular canals form from invaginations in the otic epithelium (buds) that extend and fuse to form the hubs of each canal. We find that conventional actomyosin-driven behaviors are not required. Instead, local secretion of hyaluronan, made by the enzymes uridine 5'-diphosphate dehydrogenase (ugdh) and hyaluronan synthase 3 (has3), drives canal morphogenesis. Charged hyaluronate polymers osmotically swell with water and generate isotropic extracellular pressure to deform the overlying epithelium into buds. The mechanical anisotropy needed to shape buds into tubes is conferred by a polarized distribution of actomyosin and E-cadherin-rich membrane tethers, which we term cytocinches. Most work on tissue morphogenesis ascribes actomyosin contractility as the driving force, while the extracellular matrix shapes tissues through differential stiffness. Our work inverts this expectation. Hyaluronate pressure shaped by anisotropic tissue stiffness may be a widespread mechanism for powering morphological change in organogenesis and tissue engineering.


Assuntos
Espaço Extracelular/química , Ácido Hialurônico/farmacologia , Morfogênese , Especificidade de Órgãos , Pressão , Canais Semicirculares/citologia , Canais Semicirculares/embriologia , Actomiosina/metabolismo , Animais , Anisotropia , Comportamento Animal , Matriz Extracelular/metabolismo , Ácido Hialurônico/biossíntese , Modelos Biológicos , Morfogênese/efeitos dos fármacos , Especificidade de Órgãos/efeitos dos fármacos , Pressão Osmótica , Canais Semicirculares/diagnóstico por imagem , Comportamento Estereotipado , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra/metabolismo
7.
Nat Commun ; 12(1): 7322, 2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34916498

RESUMO

Blastocyst-derived stem cell lines were shown to self-organize into embryo-like structures in 3D cell culture environments. Here, we provide evidence that embryo-like structures can be generated solely based on transcription factor-mediated reprogramming of embryonic stem cells in a simple 3D co-culture system. Embryonic stem cells in these cultures self-organize into elongated, compartmentalized embryo-like structures reflecting aspects of the inner regions of the early post-implantation embryo. Single-cell RNA-sequencing reveals transcriptional profiles resembling epiblast, primitive-/visceral endoderm, and extraembryonic ectoderm of early murine embryos around E4.5-E5.5. In this stem cell-based embryo model, progression from rosette formation to lumenogenesis accompanied by progression from naïve- to primed pluripotency was observed within Epi-like cells. Additionally, lineage specification of primordial germ cells and distal/anterior visceral endoderm-like cells was observed in epiblast- or visceral endoderm-like compartments, respectively. The system presented in this study allows for fast and reproducible generation of embryo-like structures, providing an additional tool to study aspects of early embryogenesis.


Assuntos
Corpos Embrioides/citologia , Desenvolvimento Embrionário , Células-Tronco Embrionárias/citologia , Animais , Blastocisto/citologia , Blastocisto/metabolismo , Reprogramação Celular , Embrião de Mamíferos/embriologia , Embrião de Mamíferos/metabolismo , Corpos Embrioides/metabolismo , Células-Tronco Embrionárias/metabolismo , Endoderma/embriologia , Endoderma/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , RNA-Seq
8.
Cells ; 10(12)2021 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-34943921

RESUMO

Nestin is a member of the intermediate filament family, which is expressed in a variety of stem or progenitor cells as well as in several types of malignancies. Nestin might be involved in tissue homeostasis or repair, but its expression has also been associated with processes that lead to a poor prognosis in various types of cancer. In this article, we review the literature related to the effect of nestin expression in the lung. According to most of the reports in the literature, nestin expression in lung cancer leads to an aggressive phenotype and resistance to chemotherapy as well as radiation treatments due to the upregulation of phenomena such as cell proliferation, angiogenesis, and metastasis. Furthermore, nestin may be involved in the pathogenesis of some non-cancer-related lung diseases. On the other hand, evidence also indicates that nestin-positive cells may have a role in lung homeostasis and be capable of generating various types of lung tissues. More research is necessary to establish the true value of nestin expression as a prognostic factor and therapeutic target in lung cancer in addition to its usefulness in therapeutic approaches for pulmonary diseases.


Assuntos
Pulmão/citologia , Nestina/metabolismo , Envelhecimento/metabolismo , Animais , Humanos , Pulmão/embriologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Modelos Biológicos , Nestina/química , Células-Tronco/metabolismo
9.
Cells ; 10(12)2021 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-34943930

RESUMO

Experimental models of the central nervous system (CNS) are imperative for developmental and pathophysiological studies of neurological diseases. Among these models, three-dimensional (3D) induced pluripotent stem cell (iPSC)-derived brain organoid models have been successful in mitigating some of the drawbacks of 2D models; however, they are plagued by high organoid-to-organoid variability, making it difficult to compare specific gene regulatory pathways across 3D organoids with those of the native brain. Single-cell RNA sequencing (scRNA-seq) transcriptome datasets have recently emerged as powerful tools to perform integrative analyses and compare variability across organoids. However, transcriptome studies focusing on late-stage neural functionality development have been underexplored. Here, we combine and analyze 8 brain organoid transcriptome databases to study the correlation between differentiation protocols and their resulting cellular functionality across various 3D organoid and exogenous brain models. We utilize dimensionality reduction methods including principal component analysis (PCA) and uniform manifold approximation projection (UMAP) to identify and visualize cellular diversity among 3D models and subsequently use gene set enrichment analysis (GSEA) and developmental trajectory inference to quantify neuronal behaviors such as axon guidance, synapse transmission and action potential. We showed high similarity in cellular composition, cellular differentiation pathways and expression of functional genes in human brain organoids during induction and differentiation phases, i.e., up to 3 months in culture. However, during the maturation phase, i.e., 6-month timepoint, we observed significant developmental deficits and depletion of neuronal and astrocytes functional genes as indicated by our GSEA results. Our results caution against use of organoids to model pathophysiology and drug response at this advanced time point and provide insights to tune in vitro iPSC differentiation protocols to achieve desired neuronal functionality and improve current protocols.


Assuntos
Encéfalo/metabolismo , Diferenciação Celular/genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Modelos Biológicos , Organoides/metabolismo , Transcriptoma/genética , Encéfalo/embriologia , Bases de Dados Genéticas , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Neurônios/citologia , Neurônios/metabolismo , Reprodução , Análise de Sequência de RNA , Transdução de Sinais/genética , Análise de Célula Única
10.
Dev Cell ; 56(24): 3334-3348.e6, 2021 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-34932949

RESUMO

Centrioles comprise the heart of centrosomes, microtubule-organizing centers. To study the function of centrioles in lung and gut development, we genetically disrupted centrioles throughout the mouse endoderm. Surprisingly, removing centrioles from the endoderm did not disrupt intestinal growth or development but blocked lung branching. In the lung, acentriolar SOX2-expressing airway epithelial cells apoptosed. Loss of centrioles activated p53, and removing p53 restored survival of SOX2-expressing cells, lung branching, and mouse viability. To investigate how endodermal p53 activation specifically killed acentriolar SOX2-expressing cells, we assessed ERK, a prosurvival cue. ERK was active throughout the intestine and in the distal lung buds, correlating with tolerance to centriole loss. Pharmacologically inhibiting ERK activated apoptosis in acentriolar cells, revealing that ERK activity protects acentriolar cells from apoptosis. Therefore, centrioles are largely dispensable for endodermal growth and the spatial distribution of ERK activity in the endoderm shapes the developmental consequences of centriolar defects and p53 activation.


Assuntos
Apoptose , Centríolos/metabolismo , Endoderma/embriologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Sobrevivência Celular , Endoderma/metabolismo , Células Epiteliais/metabolismo , Intestinos/crescimento & desenvolvimento , Pulmão/embriologia , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/metabolismo , Morfogênese , Fatores de Transcrição SOXB1/metabolismo , Células-Tronco/metabolismo
11.
Nat Commun ; 12(1): 7235, 2021 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-34903763

RESUMO

Developmental genes are frequently controlled by multiple enhancers sharing similar specificities. As a result, deletions of such regulatory elements have often failed to reveal their full function. Here, we use the Pitx1 testbed locus to characterize in detail the regulatory and cellular identity alterations following the deletion of one of its enhancers (Pen). By combining single cell transcriptomics and an in-embryo cell tracing approach, we observe an increased fraction of Pitx1 non/low-expressing cells and a decreased fraction of Pitx1 high-expressing cells. We find that the over-representation of Pitx1 non/low-expressing cells originates from a failure of the Pitx1 locus to coordinate enhancer activities and 3D chromatin changes. This locus mis-activation induces a localized heterochrony and a concurrent loss of irregular connective tissue, eventually leading to a clubfoot phenotype. This data suggests that, in some cases, redundant enhancers may be used to locally enforce a robust activation of their host regulatory landscapes.


Assuntos
Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica no Desenvolvimento , Fatores de Transcrição Box Pareados/genética , Acetilação , Animais , Cromatina/química , Cromatina/metabolismo , Tecido Conjuntivo/crescimento & desenvolvimento , Tecido Conjuntivo/metabolismo , Embrião de Mamíferos , Epigênese Genética , Membro Posterior/citologia , Membro Posterior/embriologia , Membro Posterior/metabolismo , Botões de Extremidades/citologia , Botões de Extremidades/embriologia , Botões de Extremidades/metabolismo , Camundongos , Modelos Genéticos , Fatores de Transcrição Box Pareados/metabolismo , Deleção de Sequência
12.
Nat Commun ; 12(1): 7334, 2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34921133

RESUMO

The erythroid terminal differentiation program couples sequential cell divisions with progressive reductions in cell size. The erythropoietin receptor (EpoR) is essential for erythroblast survival, but its other functions are not well characterized. Here we use Epor-/- mouse erythroblasts endowed with survival signaling to identify novel non-redundant EpoR functions. We find that, paradoxically, EpoR signaling increases red cell size while also increasing the number and speed of erythroblast cell cycles. EpoR-regulation of cell size is independent of established red cell size regulation by iron. High erythropoietin (Epo) increases red cell size in wild-type mice and in human volunteers. The increase in mean corpuscular volume (MCV) outlasts the duration of Epo treatment and is not the result of increased reticulocyte number. Our work shows that EpoR signaling alters the relationship between cycling and cell size. Further, diagnostic interpretations of increased MCV should now include high Epo levels and hypoxic stress.


Assuntos
Ciclo Celular , Tamanho Celular , Eritrócitos/citologia , Eritrócitos/metabolismo , Eritropoese , Receptores da Eritropoetina/metabolismo , Adulto , Animais , Antígenos CD/metabolismo , Antígenos CD4/metabolismo , Diferenciação Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Sobrevivência Celular , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Embrião de Mamíferos/metabolismo , Eritroblastos/citologia , Eritroblastos/efeitos dos fármacos , Eritroblastos/metabolismo , Eritropoetina/administração & dosagem , Eritropoetina/farmacologia , Feminino , Feto/metabolismo , Voluntários Saudáveis , Humanos , Ferro/metabolismo , Fígado/embriologia , Fígado/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Modelos Biológicos , Receptores da Transferrina/metabolismo , Reticulócitos/citologia , Reticulócitos/efeitos dos fármacos , Reticulócitos/metabolismo , Transdução de Sinais , Proteína bcl-X/metabolismo
14.
Development ; 148(19)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34608934

RESUMO

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by an expansion of the CAG repeats in the huntingtin gene (HTT). Although HD has been shown to have a developmental component, how early during human embryogenesis the HTT-CAG expansion can cause embryonic defects remains unknown. Here, we demonstrate a specific and highly reproducible CAG length-dependent phenotypic signature in a synthetic model for human gastrulation derived from human embryonic stem cells (hESCs). Specifically, we observed a reduction in the extension of the ectodermal compartment that is associated with enhanced activin signaling. Surprisingly, rather than a cell-autonomous effect, tracking the dynamics of TGFß signaling demonstrated that HTT-CAG expansion perturbs the spatial restriction of activin response. This is due to defects in the apicobasal polarization in the context of the polarized epithelium of the 2D gastruloid, leading to ectopic subcellular localization of TGFß receptors. This work refines the earliest developmental window for the prodromal phase of HD to the first 2 weeks of human development, as modeled by our 2D gastruloids.


Assuntos
Linhagem da Célula , Polaridade Celular , Camadas Germinativas/metabolismo , Células-Tronco Embrionárias Humanas/metabolismo , Proteína Huntingtina/metabolismo , Ativinas/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Camadas Germinativas/citologia , Camadas Germinativas/embriologia , Células-Tronco Embrionárias Humanas/citologia , Humanos , Proteína Huntingtina/genética , Camundongos , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo , Expansão das Repetições de Trinucleotídeos
15.
Elife ; 102021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34609280

RESUMO

During morphogenesis, epithelial sheets remodel into complex geometries. How cells dynamically organise their contact with neighbouring cells in these tightly packed tissues is poorly understood. We have used light-sheet microscopy of growing mouse embryonic lung explants, three-dimensional cell segmentation, and physical theory to unravel the principles behind 3D cell organisation in growing pseudostratified epithelia. We find that cells have highly irregular 3D shapes and exhibit numerous neighbour intercalations along the apical-basal axis as well as over time. Despite the fluidic nature, the cell packing configurations follow fundamental relationships previously described for apical epithelial layers, that is, Euler's polyhedron formula, Lewis' law, and Aboav-Weaire's law, at all times and across the entire tissue thickness. This arrangement minimises the lateral cell-cell surface energy for a given cross-sectional area variability, generated primarily by the distribution and movement of nuclei. We conclude that the complex 3D cell organisation in growing epithelia emerges from simple physical principles.


Assuntos
Pulmão/embriologia , Animais , Células Epiteliais/citologia , Epitélio/embriologia , Camundongos , Morfogênese
16.
Elife ; 102021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34609281

RESUMO

Brain microglia and border-associated macrophages (BAMs) display distinct spatial, developmental, and phenotypic features. Although at steady state, the origins of distinct brain macrophages are well-documented, the dynamics of their replenishment in neurodegenerative disorders remain elusive, particularly for activated CD11c+ microglia and BAMs. In this study, we conducted a comprehensive fate-mapping analysis of murine microglia and BAMs and their turnover kinetics during Alzheimer's disease (AD) progression. We used a novel inducible AD mouse model to investigate the contribution of bone marrow (BM) cells to the pool of fetal-derived brain macrophages during the development of AD. We demonstrated that microglia remain a remarkably stable embryonic-derived population even during the progression of AD pathology, indicating that neither parenchymal macrophage subpopulation originates from, nor is replenished by, BM-derived cells. At the border-associated brain regions, bona fide CD206+ BAMs are minimally replaced by BM-derived cells, and their turnover rates are not accelerated by AD. In contrast, all other myeloid cells are swiftly replenished by BM progenitors. This information further elucidates the turnover kinetics of these cells not only at steady state, but also in neurodegenerative diseases, which is crucial for identifying potential novel therapeutic targets.


Assuntos
Doença de Alzheimer/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/metabolismo , Lectinas de Ligação a Manose/metabolismo , Microglia/metabolismo , Receptores de Superfície Celular/metabolismo , Doença de Alzheimer/embriologia , Animais , Modelos Animais de Doenças , Camundongos
17.
Elife ; 102021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34605405

RESUMO

PERK is an endoplasmic reticulum (ER) transmembrane sensor that phosphorylates eIF2α to initiate the Unfolded Protein Response (UPR). eIF2α phosphorylation promotes stress-responsive gene expression most notably through the transcription factor ATF4 that contains a regulatory 5' leader. Possible PERK effectors other than ATF4 remain poorly understood. Here, we report that the bZIP transcription factor Xrp1 is required for ATF4-independent PERK signaling. Cell-type-specific gene expression profiling in Drosophila indicated that delta-family glutathione-S-transferases (gstD) are prominently induced by the UPR-activating transgene Rh1G69D. Perk was necessary and sufficient for such gstD induction, but ATF4 was not required. Instead, Perk and other regulators of eIF2α phosphorylation regulated Xrp1 protein levels to induce gstDs. The Xrp1 5' leader has a conserved upstream Open Reading Frame (uORF) analogous to those that regulate ATF4 translation. The gstD-GFP reporter induction required putative Xrp1 binding sites. These results indicate that antioxidant genes are highly induced by a previously unrecognized UPR signaling axis consisting of PERK and Xrp1.


Assuntos
Antioxidantes/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimologia , Glutationa Transferase/metabolismo , Discos Imaginais/enzimologia , eIF-2 Quinase/metabolismo , Animais , Animais Geneticamente Modificados , Sítios de Ligação , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Estresse do Retículo Endoplasmático , Fator de Iniciação 2 em Eucariotos/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Glutationa Transferase/genética , Discos Imaginais/embriologia , Fases de Leitura Aberta , Fosforilação , Rodopsina/genética , Rodopsina/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Resposta a Proteínas não Dobradas , eIF-2 Quinase/genética
18.
Nature ; 598(7879): 174-181, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34616072

RESUMO

Dendritic and axonal morphology reflects the input and output of neurons and is a defining feature of neuronal types1,2, yet our knowledge of its diversity remains limited. Here, to systematically examine complete single-neuron morphologies on a brain-wide scale, we established a pipeline encompassing sparse labelling, whole-brain imaging, reconstruction, registration and analysis. We fully reconstructed 1,741 neurons from cortex, claustrum, thalamus, striatum and other brain regions in mice. We identified 11 major projection neuron types with distinct morphological features and corresponding transcriptomic identities. Extensive projectional diversity was found within each of these major types, on the basis of which some types were clustered into more refined subtypes. This diversity follows a set of generalizable principles that govern long-range axonal projections at different levels, including molecular correspondence, divergent or convergent projection, axon termination pattern, regional specificity, topography, and individual cell variability. Although clear concordance with transcriptomic profiles is evident at the level of major projection type, fine-grained morphological diversity often does not readily correlate with transcriptomic subtypes derived from unsupervised clustering, highlighting the need for single-cell cross-modality studies. Overall, our study demonstrates the crucial need for quantitative description of complete single-cell anatomy in cell-type classification, as single-cell morphological diversity reveals a plethora of ways in which different cell types and their individual members may contribute to the configuration and function of their respective circuits.


Assuntos
Encéfalo/citologia , Forma Celular , Neurônios/classificação , Neurônios/metabolismo , Análise de Célula Única , Atlas como Assunto , Biomarcadores/metabolismo , Encéfalo/anatomia & histologia , Encéfalo/embriologia , Encéfalo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Neocórtex/anatomia & histologia , Neocórtex/citologia , Neocórtex/embriologia , Neocórtex/metabolismo , Neurogênese , Neuroglia/citologia , Neurônios/citologia , RNA-Seq , Reprodutibilidade dos Testes
19.
Development ; 148(19)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34610637

RESUMO

Many developmental disorders are thought to arise from an interaction between genetic and environmental risk factors. The Hedgehog (HH) signaling pathway regulates myriad developmental processes, and pathway inhibition is associated with birth defects, including holoprosencephaly (HPE). Cannabinoids are HH pathway inhibitors, but little is known of their effects on HH-dependent processes in mammalian embryos, and their mechanism of action is unclear. We report that the psychoactive cannabinoid Δ9-tetrahydrocannabinol (THC) induces two hallmark HH loss-of-function phenotypes (HPE and ventral neural tube patterning defects) in Cdon mutant mice, which have a subthreshold deficit in HH signaling. THC therefore acts as a 'conditional teratogen', dependent on a complementary but insufficient genetic insult. In vitro findings indicate that THC is a direct inhibitor of the essential HH signal transducer smoothened. The canonical THC receptor, cannabinoid receptor-type 1, is not required for THC to inhibit HH signaling. Cannabis consumption during pregnancy may contribute to a combination of risk factors underlying specific developmental disorders. These findings therefore have significant public health relevance.


Assuntos
Padronização Corporal/efeitos dos fármacos , Agonistas de Receptores de Canabinoides/toxicidade , Dronabinol/toxicidade , Holoprosencefalia/induzido quimicamente , Receptor Smoothened/metabolismo , Teratógenos/toxicidade , Animais , Agonistas de Receptores de Canabinoides/farmacologia , Moléculas de Adesão Celular/genética , Células Cultivadas , Dronabinol/farmacologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Tubo Neural/efeitos dos fármacos , Tubo Neural/embriologia , Tubo Neural/metabolismo , Transdução de Sinais/efeitos dos fármacos , Teratógenos/farmacologia
20.
Elife ; 102021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34632981

RESUMO

Gut enzymes can metabolize plant defense compounds and thereby affect the growth and fitness of insect herbivores. Whether these enzymes also influence feeding preference is largely unknown. We studied the metabolization of taraxinic acid ß-D-glucopyranosyl ester (TA-G), a sesquiterpene lactone of the common dandelion (Taraxacum officinale) that deters its major root herbivore, the common cockchafer larva (Melolontha melolontha). We have demonstrated that TA-G is rapidly deglucosylated and conjugated to glutathione in the insect gut. A broad-spectrum M. melolontha ß-glucosidase, Mm_bGlc17, is sufficient and necessary for TA-G deglucosylation. Using cross-species RNA interference, we have shown that Mm_bGlc17 reduces TA-G toxicity. Furthermore, Mm_bGlc17 is required for the preference of M. melolontha larvae for TA-G-deficient plants. Thus, herbivore metabolism modulates both the toxicity and deterrence of a plant defense compound. Our work illustrates the multifaceted roles of insect digestive enzymes as mediators of plant-herbivore interactions.


Assuntos
Besouros/enzimologia , Glucosídeos/metabolismo , Herbivoria , Proteínas de Insetos/metabolismo , Lactonas/metabolismo , Sesquiterpenos/metabolismo , Taraxacum/metabolismo , beta-Galactosidase/metabolismo , Animais , Besouros/embriologia , Besouros/genética , Digestão , Glucosídeos/toxicidade , Glutationa/metabolismo , Hidrólise , Inativação Metabólica , Proteínas de Insetos/genética , Lactonas/toxicidade , Larva/enzimologia , Larva/genética , Metabolismo Secundário , Sesquiterpenos/toxicidade , Taraxacum/toxicidade , beta-Galactosidase/genética
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