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1.
Proc Natl Acad Sci U S A ; 117(37): 23073-23084, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32873638

RESUMO

The small GTPase ARL4C participates in the regulation of cell migration, cytoskeletal rearrangements, and vesicular trafficking in epithelial cells. The ARL4C signaling cascade starts by the recruitment of the ARF-GEF cytohesins to the plasma membrane, which, in turn, bind and activate the small GTPase ARF6. However, the role of ARL4C-cytohesin-ARF6 signaling during hippocampal development remains elusive. Here, we report that the E3 ubiquitin ligase Cullin 5/RBX2 (CRL5) controls the stability of ARL4C and its signaling effectors to regulate hippocampal morphogenesis. Both RBX2 knockout and Cullin 5 knockdown cause hippocampal pyramidal neuron mislocalization and development of multiple apical dendrites. We used quantitative mass spectrometry to show that ARL4C, Cytohesin-1/3, and ARF6 accumulate in the RBX2 mutant telencephalon. Furthermore, we show that depletion of ARL4C rescues the phenotypes caused by Cullin 5 knockdown, whereas depletion of CYTH1 or ARF6 exacerbates overmigration. Finally, we show that ARL4C, CYTH1, and ARF6 are necessary for the dendritic outgrowth of pyramidal neurons to the superficial strata of the hippocampus. Overall, we identified CRL5 as a key regulator of hippocampal development and uncovered ARL4C, CYTH1, and ARF6 as CRL5-regulated signaling effectors that control pyramidal neuron migration and dendritogenesis.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Proteínas Culina/metabolismo , Hipocampo/metabolismo , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Morfogênese/fisiologia , Animais , Membrana Celular/metabolismo , Movimento Celular/fisiologia , Dendritos/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Camundongos , Neurogênese/fisiologia , Células Piramidais/metabolismo , Transdução de Sinais/fisiologia , Ubiquitina-Proteína Ligases/metabolismo
2.
Nat Commun ; 11(1): 3910, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764693

RESUMO

SARS-CoV-2, a ß-coronavirus, has rapidly spread across the world, highlighting its high transmissibility, but the underlying morphogenesis and pathogenesis remain poorly understood. Here, we characterize the replication dynamics, cell tropism and morphogenesis of SARS-CoV-2 in organotypic human airway epithelial (HAE) cultures. SARS-CoV-2 replicates efficiently and infects both ciliated and secretory cells in HAE cultures. In comparison, HCoV-NL63 replicates to lower titers and is only detected in ciliated cells. SARS-CoV-2 shows a similar morphogenetic process as other coronaviruses but causes plaque-like cytopathic effects in HAE cultures. Cell fusion, apoptosis, destruction of epithelium integrity, cilium shrinking and beaded changes are observed in the plaque regions. Taken together, our results provide important insights into SARS-CoV-2 cell tropism, replication and morphogenesis.


Assuntos
Betacoronavirus/fisiologia , Infecções por Coronavirus/virologia , Células Epiteliais/virologia , Morfogênese/fisiologia , Pneumonia Viral/virologia , Sistema Respiratório/virologia , Betacoronavirus/patogenicidade , Linhagem Celular , Células Cultivadas , Efeito Citopatogênico Viral , Células Epiteliais/patologia , Humanos , Pandemias , Sistema Respiratório/patologia , Tropismo , Replicação Viral
3.
PLoS Comput Biol ; 16(8): e1008049, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32822341

RESUMO

Tissue morphogenesis relies on repeated use of dynamic behaviors at the levels of intracellular structures, individual cells, and cell groups. Rapidly accumulating live imaging datasets make it increasingly important to formalize and automate the task of mapping recurrent dynamic behaviors (motifs), as it is done in speech recognition and other data mining applications. Here, we present a "template-based search" approach for accurate mapping of sub- to multi-cellular morphogenetic motifs using a time series data mining framework. We formulated the task of motif mapping as a subsequence matching problem and solved it using dynamic time warping, while relying on high throughput graph-theoretic algorithms for efficient exploration of the search space. This formulation allows our algorithm to accurately identify the complete duration of each instance and automatically label different stages throughout its progress, such as cell cycle phases during cell division. To illustrate our approach, we mapped cell intercalations during germband extension in the early Drosophila embryo. Our framework enabled statistical analysis of intercalary cell behaviors in wild-type and mutant embryos, comparison of temporal dynamics in contracting and growing junctions in different genotypes, and the identification of a novel mode of iterative cell intercalation. Our formulation of tissue morphogenesis using time series opens new avenues for systematic decomposition of tissue morphogenesis.


Assuntos
Biologia Computacional/métodos , Processamento de Imagem Assistida por Computador/métodos , Morfogênese/fisiologia , Algoritmos , Animais , Divisão Celular/fisiologia , Mineração de Dados/métodos , Drosophila/citologia , Drosophila/embriologia , Embrião não Mamífero/citologia , Embrião não Mamífero/embriologia , Feminino , Masculino , Microscopia Confocal , Fatores de Tempo
4.
Nat Commun ; 11(1): 3516, 2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665580

RESUMO

It is unclear whether the establishment of apical-basal cell polarity during the generation of epithelial lumens requires molecules acting at the plasma membrane/actin interface. Here, we show that the I-BAR-containing IRSp53 protein controls lumen formation and the positioning of the polarity determinants aPKC and podocalyxin. Molecularly, IRSp53 acts by regulating the localization and activity of the small GTPase RAB35, and by interacting with the actin capping protein EPS8. Using correlative light and electron microscopy, we further show that IRSp53 ensures the shape and continuity of the opposing plasma membrane of two daughter cells, leading to the formation of a single apical lumen. Genetic removal of IRSp53 results in abnormal renal tubulogenesis, with altered tubular polarity and architectural organization. Thus, IRSp53 acts as a membrane curvature-sensing platform for the assembly of multi-protein complexes that control the trafficking of apical determinants and the integrity of the luminal plasma membrane.


Assuntos
Membrana Celular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Actinas/metabolismo , Polaridade Celular/genética , Polaridade Celular/fisiologia , Células Epiteliais/metabolismo , Feminino , Humanos , Morfogênese/genética , Morfogênese/fisiologia , Proteínas do Tecido Nervoso/genética , Transporte Proteico/genética , Transporte Proteico/fisiologia , Sialoglicoproteínas/genética , Sialoglicoproteínas/metabolismo , Proteínas rab de Ligação ao GTP/genética
5.
Nat Cell Biol ; 22(5): 534-545, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32367046

RESUMO

Following implantation, the naive pluripotent epiblast of the mouse blastocyst generates a rosette, undergoes lumenogenesis and forms the primed pluripotent egg cylinder, which is able to generate the embryonic tissues. How pluripotency progression and morphogenesis are linked and whether intermediate pluripotent states exist remain controversial. We identify here a rosette pluripotent state defined by the co-expression of naive factors with the transcription factor OTX2. Downregulation of blastocyst WNT signals drives the transition into rosette pluripotency by inducing OTX2. The rosette then activates MEK signals that induce lumenogenesis and drive progression to primed pluripotency. Consequently, combined WNT and MEK inhibition supports rosette-like stem cells, a self-renewing naive-primed intermediate. Rosette-like stem cells erase constitutive heterochromatin marks and display a primed chromatin landscape, with bivalently marked primed pluripotency genes. Nonetheless, WNT induces reversion to naive pluripotency. The rosette is therefore a reversible pluripotent intermediate whereby control over both pluripotency progression and morphogenesis pivots from WNT to MEK signals.


Assuntos
Células-Tronco Embrionárias/fisiologia , Células-Tronco Pluripotentes/fisiologia , Animais , Blastocisto/metabolismo , Blastocisto/fisiologia , Diferenciação Celular/fisiologia , Cromatina/metabolismo , Células-Tronco Embrionárias/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Camadas Germinativas/metabolismo , Camadas Germinativas/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Morfogênese/fisiologia , Fatores de Transcrição Otx/metabolismo , Células-Tronco Pluripotentes/metabolismo
6.
PLoS Genet ; 16(3): e1008674, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32196494

RESUMO

Epithelial cell polarity defects support cancer progression. It is thus crucial to decipher the functional interactions within the polarity protein network. Here we show that Drosophila Girdin and its human ortholog (GIRDIN) sustain the function of crucial lateral polarity proteins by inhibiting the apical kinase aPKC. Loss of GIRDIN expression is also associated with overgrowth of disorganized cell cysts. Moreover, we observed cell dissemination from GIRDIN knockdown cysts and tumorspheres, thereby showing that GIRDIN supports the cohesion of multicellular epithelial structures. Consistent with these observations, alteration of GIRDIN expression is associated with poor overall survival in subtypes of breast and lung cancers. Overall, we discovered a core mechanism contributing to epithelial cell polarization from flies to humans. Our data also indicate that GIRDIN has the potential to impair the progression of epithelial cancers by preserving cell polarity and restricting cell dissemination.


Assuntos
Proteínas de Drosophila/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas dos Microfilamentos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Células CACO-2 , Diferenciação Celular/fisiologia , Polaridade Celular/fisiologia , Proliferação de Células/fisiologia , Proteínas de Drosophila/genética , Drosophila melanogaster , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Feminino , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/genética , Morfogênese/fisiologia , Mapas de Interação de Proteínas , Proteína Quinase C/metabolismo , Proteínas de Transporte Vesicular/genética
7.
Dev Cell ; 53(1): 73-85.e5, 2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32142630

RESUMO

Airway smooth muscle is best known for its role as an airway constrictor in diseases such as asthma. However, its function in lung development is debated. A prevalent model, supported by in vitro data, posits that airway smooth muscle promotes lung branching through peristalsis and pushing intraluminal fluid to branching tips. Here, we test this model in vivo by inactivating Myocardin, which prevented airway smooth muscle differentiation. We found that Myocardin mutants show normal branching, despite the absence of peristalsis. In contrast, tracheal cartilage, vasculature, and neural innervation patterns were all disrupted. Furthermore, airway diameter is reduced in the mutant, counter to the expectation that the absence of smooth muscle constriction would lead to a more relaxed and thereby wider airway. These findings together demonstrate that during development, while airway smooth muscle is dispensable for epithelial branching, it is integral for building the tracheal architecture and promoting airway growth.


Assuntos
Cartilagem/citologia , Diferenciação Celular/fisiologia , Células Epiteliais/citologia , Músculo Liso/citologia , Animais , Pulmão/citologia , Morfogênese/fisiologia , Contração Muscular/fisiologia , Proteínas Nucleares/metabolismo , Transativadores/metabolismo
8.
PLoS One ; 15(3): e0230380, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163511

RESUMO

Epidermal morphogenesis and hair follicle (HF) development depend on the ability of keratinocytes to adhere to the basement membrane (BM) and migrate along the extracellular matrix. Integrins are cell-matrix receptors that control keratinocyte adhesion and migration, and are recognized as major regulators of epidermal homeostasis. How integrins regulate the behavior of keratinocytes during epidermal morphogenesis remains insufficiently understood. Here, we show that α-parvin (α-pv), a focal adhesion protein that couples integrins to actin cytoskeleton, is indispensable for epidermal morphogenesis and HF development. Inactivation of the murine α-pv gene in basal keratinocytes results in keratinocyte-BM detachment, epidermal thickening, ectopic keratinocyte proliferation and altered actin cytoskeleton polarization. In vitro, α-pv-null keratinocytes display reduced adhesion to BM matrix components, aberrant spreading and stress fibers formation, and impaired directed migration. Together, our data demonstrate that α-pv controls epidermal homeostasis by facilitating integrin-mediated adhesion and actin cytoskeleton organization in keratinocytes.


Assuntos
Membrana Basal/metabolismo , Epiderme/crescimento & desenvolvimento , Folículo Piloso/metabolismo , Queratinócitos/metabolismo , Proteínas dos Microfilamentos/fisiologia , Morfogênese/fisiologia , Actinas/metabolismo , Animais , Membrana Basal/citologia , Adesão Celular/fisiologia , Movimento Celular/fisiologia , Células Cultivadas , Adesões Focais/metabolismo , Integrinas/metabolismo , Queratinócitos/citologia , Camundongos , Camundongos Transgênicos
9.
Proc Natl Acad Sci U S A ; 117(9): 4792-4801, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32075915

RESUMO

Angiogenesis, the formation of new blood vessels, is tightly regulated by gene transcriptional programs. Yin Ying 1 (YY1) is a ubiquitously distributed transcription factor with diverse and complex biological functions; however, little is known about the cell-type-specific role of YY1 in vascular development and angiogenesis. Here we report that endothelial cell (EC)-specific YY1 deletion in mice led to embryonic lethality as a result of abnormal angiogenesis and vascular defects. Tamoxifen-inducible EC-specific YY1 knockout (YY1 iΔEC ) mice exhibited a scarcity of retinal sprouting angiogenesis with fewer endothelial tip cells. YY1 iΔEC mice also displayed severe impairment of retinal vessel maturation. In an ex vivo mouse aortic ring assay and a human EC culture system, YY1 depletion impaired endothelial sprouting and migration. Mechanistically, YY1 functions as a repressor protein of Notch signaling that controls EC tip-stalk fate determination. YY1 deficiency enhanced Notch-dependent gene expression and reduced tip cell formation. Specifically, YY1 bound to the N-terminal domain of RBPJ (recombination signal binding protein for Ig Kappa J region) and competed with the Notch coactivator MAML1 (mastermind-like protein 1) for binding to RBPJ, thereby impairing the NICD (intracellular domain of the Notch protein)/MAML1/RBPJ complex formation. Our study reveals an essential role of endothelial YY1 in controlling sprouting angiogenesis through directly interacting with RBPJ and forming a YY1-RBPJ nuclear repression complex.


Assuntos
Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Morfogênese/fisiologia , Neovascularização Patológica/metabolismo , Fator de Transcrição YY1/metabolismo , Animais , Proteínas de Transporte/metabolismo , Diferenciação Celular , Células Endoteliais/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Masculino , Camundongos/embriologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Neovascularização Fisiológica/genética , Neovascularização Fisiológica/fisiologia , Proteínas Nucleares , Ligação Proteica , Receptores Notch/metabolismo , Vasos Retinianos/metabolismo , Transdução de Sinais , Fatores de Transcrição , Fator de Transcrição YY1/genética
10.
Parasitol Res ; 119(5): 1583-1595, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32107619

RESUMO

Results of the present study provide ultrastructural evidence that miracidial morphogenesis is fully completed within the intrauterine eggs while in the most posterior uterine regions of Ityogonimus lorum, a digenean parasite of an Iberian mole, Talpa occidentalis (Eulipotyphla, Talpidae). Using transmission electron microscopy (TEM), the ultrastructural characteristics of diverse cell types and their organelles of these developing embryos and fully formed miracidia within the eggshell were examined. The eggshell and embryonic envelopes are similar to those described previously by many authors for other digeneans. However, the developing miracidia are unique among previously described digeneans in possessing transitory cilia during larvigenesis, but completely lacking cilia in fully formed miracidium larvae. The evidence for completion of miracidial maturation in intrauterine eggs is based on the presence of the following structures: (1) transitional stage of ciliated differentiating miracidial epithelium; (2) apical and lateral glands, characteristic for digenean miracidia; and (3) fully developed germinative cells grouped together in the germinative sac localized in the posterior region of the miracidium. The protonephridial system with its characteristic flame cells and the nervous system with diverse types of neurons and nerve centers, which are characteristic for other digenean species reported until now, are absent from all these developmental stages of I. lorum. Based on these observations, we hypothesize that the life cycle of I. lorum is entirely terrestrial, involving passive transmission by ingestion of eggs containing unciliated miracidia to the first intermediate host.


Assuntos
Desenvolvimento Embrionário/fisiologia , Morfogênese/fisiologia , Trematódeos/embriologia , Trematódeos/ultraestrutura , Infecções por Trematódeos/transmissão , Animais , Feminino , Histocitoquímica , Larva/anatomia & histologia , Larva/crescimento & desenvolvimento , Microscopia Eletrônica de Transmissão , Toupeiras/parasitologia , Trematódeos/classificação , Útero/parasitologia
11.
Exp Eye Res ; 191: 107917, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31923414

RESUMO

The transparent and refractive properties of the ocular lens are dependent on its precise cellular structure, supported by the regulation of lens cellular processes of proliferation and differentiation that are essential throughout life. The ERK/MAPK-signalling pathway plays a crucial role in regulating lens cell proliferation and differentiation, and in turn is regulated by inhibitory molecules including the Spred family of proteins to modulate and attenuate the impact of growth factor stimulation. Given Spreds are strongly and distinctly expressed in lens, along with their established inhibitory role in a range of different tissues, we investigated the role these antagonists play in regulating lens cell proliferation and differentiation, and their contribution to lens structure and growth. Using established mice lines deficient for either or both Spred 1 and Spred 2, we demonstrate their role in regulating lens development by negatively regulating ERK1/2 activity. Mice deficient for both Spred 1 and Spred 2 have impaired lens and eye development, displaying irregular lens epithelial and fibre cell activity as a result of increased levels of phosphorylated ERK1/2. While Spred 1 and Spred 2 do not appear to be necessary for induction and early stages of lens morphogenesis (prior to E11.5), nor for the formation of the primary fibre cells, they are required for the continuous embryonic growth and differentiation of the lens.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Olho/embriologia , Cristalino/embriologia , Morfogênese/fisiologia , Proteínas Repressoras/fisiologia , Animais , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Feminino , Técnicas de Genotipagem , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Reação em Cadeia da Polimerase
12.
Bioessays ; 42(2): e1900146, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31994772

RESUMO

Evolution exploits the physics of non-neural bioelectricity to implement anatomical homeostasis: a process in which embryonic patterning, remodeling, and regeneration achieve invariant anatomical outcomes despite external interventions. Linear "developmental pathways" are often inadequate explanations for dynamic large-scale pattern regulation, even when they accurately capture relationships between molecular components. Biophysical and computational aspects of collective cell activity toward a target morphology reveal interesting aspects of causation in biology. This is critical not only for unraveling evolutionary and developmental events, but also for the design of effective strategies for biomedical intervention. Bioelectrical controls of growth and form, including stochastic behavior in such circuits, highlight the need for the formulation of nuanced views of pathways, drivers of system-level outcomes, and modularity, borrowing from concepts in related disciplines such as cybernetics, control theory, computational neuroscience, and information theory. This approach has numerous practical implications for basic research and for applications in regenerative medicine and synthetic bioengineering.


Assuntos
Morfogênese/fisiologia , Regeneração/fisiologia , Animais , Bioengenharia/métodos , Biofísica/métodos , Homeostase/fisiologia , Humanos , Modelos Biológicos , Neurociências/métodos , Medicina Regenerativa/métodos
13.
Artigo em Inglês | MEDLINE | ID: mdl-31913700

RESUMO

Septate junctions (SJs) are occluding cell-cell junctions that have roles in paracellular permeability and barrier function in the epithelia of invertebrates. Arthropods have two types of SJs, pleated SJs and smooth SJs (sSJs). In Drosophila melanogaster, sSJs are found in the midgut and Malpighian tubules, but the functions of sSJs and their protein components in the tubule epithelium are unknown. Here we examined the role of the previously identified integral sSJ component, Mesh, in the Malpighian tubule. We genetically manipulated mesh specifically in the principal cells of the tubule at different life stages. Tubules of flies with developmental mesh knockdown revealed defects in epithelial architecture, sSJ molecular and structural organization, and lack of urine production in basal and kinin-stimulated conditions, resulting in edema and early adult lethality. Knockdown of mesh during adulthood did not disrupt tubule epithelial and sSJ integrity but decreased the transepithelial potential, diminished transepithelial fluid and ion transport, and decreased paracellular permeability to 4-kDa dextran. Drosophila kinin decreased transepithelial potential and increased chloride permeability, and it stimulated fluid secretion in both control and adult mesh knockdown tubules but had no effect on 4-kDa dextran flux. Together, these data indicate roles for Mesh in the developmental maturation of the Drosophila Malpighian tubule and in ion and macromolecular transport in the adult tubule.


Assuntos
Permeabilidade da Membrana Celular/fisiologia , Proteínas de Drosophila/deficiência , Epitélio/metabolismo , Epitélio/ultraestrutura , Túbulos de Malpighi/metabolismo , Túbulos de Malpighi/ultraestrutura , Proteínas de Membrana/deficiência , Morfogênese/fisiologia , Animais , Animais Geneticamente Modificados , Proteínas de Drosophila/genética , Drosophila melanogaster , Feminino , Transporte de Íons/fisiologia , Proteínas de Membrana/genética
14.
Proc Natl Acad Sci U S A ; 117(3): 1552-1558, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31900360

RESUMO

Buffering variability in morphogen distribution is essential for reproducible patterning. A theoretically proposed class of mechanisms, termed "distal pinning," achieves robustness by combining local sensing of morphogen levels with global modulation of gradient spread. Here, we demonstrate a critical role for morphogen sensing by a gene enhancer, which ultimately determines the final global distribution of the morphogen and enables reproducible patterning. Specifically, we show that, while the pattern of Toll activation in the early Drosophila embryo is robust to gene dosage of its locally produced regulator, WntD, it is sensitive to a single-nucleotide change in the wntD enhancer. Thus, enhancer properties of locally produced WntD directly impinge on the global morphogen profile.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/embriologia , Drosophila/genética , Drosophila/metabolismo , Elementos Facilitadores Genéticos/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Animais , Sítios de Ligação , Padronização Corporal , Proteínas de Drosophila/genética , Desenvolvimento Embrionário/genética , Gástrula/fisiologia , Dosagem de Genes , Regulação da Expressão Gênica no Desenvolvimento , Proteínas HMGB/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Morfogênese/genética , Morfogênese/fisiologia , Proteínas Repressoras/metabolismo , Alinhamento de Sequência , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Receptores Toll-Like/genética , Receptores Toll-Like/metabolismo
15.
Cell Mol Life Sci ; 77(3): 543-558, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31243490

RESUMO

Desmosome-anchored keratin intermediate filaments (KFs) are essential for epithelial coherence. Yet, desmosomal KF attachment and network organization are still unexplored in vivo. We, therefore, monitored KF network morphogenesis in fluorescent keratin 8 knock-in murine embryos revealing keratin enrichment at newly formed desmosomes followed by KF formation, KF elongation and KF fusion. To examine details of this process and its coupling to desmosome formation, we studied fluorescent keratin and desmosomal protein reporter dynamics in the periphery of expanding HaCaT keratinocyte colonies. Less than 3 min after the start of desmosomal proteins clustering non-filamentous keratin enriched at these sites followed by KF formation and elongation. Subsequently, desmosome-anchored KFs merged into stable bundles generating a rim-and-spokes system consisting of subcortical KFs connecting desmosomes to each other and radial KFs connecting desmosomes to the cytoplasmic KF network. We conclude that desmosomes are organizing centers for the KF cytoskeleton with a hitherto unknown nucleation capacity.


Assuntos
Desmossomos/metabolismo , Queratinas/metabolismo , Morfogênese/fisiologia , Animais , Adesão Celular/fisiologia , Linhagem Celular , Citoplasma/metabolismo , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Humanos , Filamentos Intermediários/metabolismo , Queratinócitos/metabolismo , Camundongos
16.
Gut ; 69(2): 380-392, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31076402

RESUMO

OBJECTIVE: Infection of human hepatocytes by the hepatitis C virus (HCV) is a multistep process involving both viral and host factors. microRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. Given that miRNAs were indicated to regulate between 30% and 75% of all human genes, we aimed to investigate the functional and regulatory role of miRNAs for the HCV life cycle. DESIGN: To systematically reveal human miRNAs affecting the HCV life cycle, we performed a two-step functional high-throughput miRNA mimic screen in Huh7.5.1 cells infected with recombinant cell culture-derived HCV. miRNA targeting was then assessed using a combination of computational and functional approaches. RESULTS: We uncovered miR-501-3p and miR-619-3p as novel modulators of HCV assembly/release. We discovered that these miRNAs regulate O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) protein expression and identified OGT and O-GlcNAcylation as regulators of HCV morphogenesis and infectivity. Furthermore, increased OGT expression in patient-derived liver tissue was associated with HCV-induced liver disease and cancer. CONCLUSION: miR-501-3p and miR-619-3p and their target OGT are previously undiscovered regulatory host factors for HCV assembly and infectivity. In addition to its effect on HCV morphogenesis, OGT may play a role in HCV-induced liver disease and hepatocarcinogenesis.


Assuntos
Hepacivirus/patogenicidade , Hepatite C Crônica/genética , N-Acetilglucosaminiltransferases/fisiologia , Regulação da Expressão Gênica/fisiologia , Técnicas de Silenciamento de Genes/métodos , Estudo de Associação Genômica Ampla/métodos , Hepacivirus/fisiologia , Hepatite C Crônica/virologia , Hepatócitos/virologia , Interações Hospedeiro-Patógeno/genética , Humanos , Estágios do Ciclo de Vida/genética , MicroRNAs/genética , Morfogênese/fisiologia , N-Acetilglucosaminiltransferases/genética , Regulação para Cima , Virulência/genética
17.
Proc Natl Acad Sci U S A ; 117(1): 43-51, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31843921

RESUMO

Brachiopods and mollusks are 2 shell-bearing phyla that diverged from a common shell-less ancestor more than 540 million years ago. Brachiopods and bivalve mollusks have also convergently evolved a bivalved shell that displays an apparently mundane, yet striking feature from a developmental point of view: When the shell is closed, the 2 valve edges meet each other in a commissure that forms a continuum with no gaps or overlaps despite the fact that each valve, secreted by 2 mantle lobes, may present antisymmetric ornamental patterns of varying regularity and size. Interlocking is maintained throughout the entirety of development, even when the shell edge exhibits significant irregularity due to injury or other environmental influences, which suggests a dynamic physical process of pattern formation that cannot be genetically specified. Here, we derive a mathematical framework, based on the physics of shell growth, to explain how this interlocking pattern is created and regulated by mechanical instabilities. By close consideration of the geometry and mechanics of 2 lobes of the mantle, constrained both by the rigid shell that they secrete and by each other, we uncover the mechanistic basis for the interlocking pattern. Our modeling framework recovers and explains a large diversity of shell forms and highlights how parametric variations in the growth process result in morphological variation. Beyond the basic interlocking mechanism, we also consider the intricate and striking multiscale-patterned edge in certain brachiopods. We show that this pattern can be explained as a secondary instability that matches morphological trends and data.


Assuntos
Exoesqueleto/anatomia & histologia , Exoesqueleto/crescimento & desenvolvimento , Bivalves/anatomia & histologia , Bivalves/crescimento & desenvolvimento , Morfogênese/fisiologia , Animais , Evolução Biológica , Bivalves/classificação , Fenômenos Mecânicos , Modelos Anatômicos , Modelos Teóricos , Filogenia
18.
Development ; 146(24)2019 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-31862792

RESUMO

In order to contribute to the appropriate tissues during development, cells need to know their position within the embryo. This positional information is conveyed by gradients of signaling molecules, termed morphogens, that are produced in specific regions of the embryo and induce concentration-dependent responses in target tissues. Positional information is remarkably robust, and embryos often develop with the correct proportions even if large parts of the embryo are removed. In this Review, we discuss classical embryological experiments and modern quantitative analyses that have led to mechanistic insights into how morphogen gradients adapt, scale and properly pattern differently sized domains. We analyze these experimental findings in the context of mathematical models and synthesize general principles that apply to multiple systems across species and developmental stages.


Assuntos
Padronização Corporal/fisiologia , Tamanho Corporal/fisiologia , Morfogênese/fisiologia , Tamanho do Órgão/fisiologia , Regeneração/fisiologia , Animais , Movimento Celular/fisiologia , Polaridade Celular/fisiologia , Humanos , Modelos Teóricos
19.
Elife ; 82019 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-31868165

RESUMO

During cardiac development, cardiomyocytes form complex inner wall structures called trabeculae. Despite significant investigation into this process, the potential role of metabolism has not been addressed. Using single cell resolution imaging in zebrafish, we find that cardiomyocytes seeding the trabecular layer actively change their shape while compact layer cardiomyocytes remain static. We show that Erbb2 signaling, which is required for trabeculation, activates glycolysis to support changes in cardiomyocyte shape and behavior. Pharmacological inhibition of glycolysis impairs cardiac trabeculation, and cardiomyocyte-specific loss- and gain-of-function manipulations of glycolysis decrease and increase trabeculation, respectively. In addition, loss of the glycolytic enzyme pyruvate kinase M2 impairs trabeculation. Experiments with rat neonatal cardiomyocytes in culture further support these observations. Our findings reveal new roles for glycolysis in regulating cardiomyocyte behavior during cardiac wall morphogenesis.


Assuntos
Coração/embriologia , Coração/crescimento & desenvolvimento , Morfogênese/fisiologia , Miócitos Cardíacos/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Animais , Animais Geneticamente Modificados , Proliferação de Células , Regulação da Expressão Gênica no Desenvolvimento , Genes erbB-2/genética , Glicólise , Coração/fisiologia , Modelos Animais , Morfogênese/genética , Organogênese/genética , Organogênese/fisiologia , Ratos , Transdução de Sinais/fisiologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
20.
Ethiop J Health Sci ; 29(6): 689-696, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31741639

RESUMO

Background: Intestine plays a major role for the normal growth of the fetus during the prenatal period. The process of the embryonic development is not quantified histologically. Therefore the main aim of the study was to measure the thickness of all part of the wall of the small intestine that are mucosa, submucosa and muscularis externa and to look for the appearance of the Brunner's glands and Peyer's patches in the submucosa of duodenum and ileum. Methods: The present study was carried out on 30 fetuses of gestational ages ranging from 11-36 weeks. Ten fetuses from each trimester were used in the study. Fetal small intestine were dissected carefully, and were separated as duodenum, jejunum & ileum and fixed in formalin solution. The tissue was processed for histology and then slides were stained with Haematoxylin and Eosin. The microscopic features were noted using light microscope. Results: The thickness of the mucosa, submucosa and the muscularis externa was observed to be increased in first trimester, decreased in the second trimester and again increased in the third trimester, which could be because of the increase cell turnover and the arrangement of the collagen fibers as to support the mucosa and the muscularis externa. Conclusion: Thus, the knowledge of the histogenesis and histomorphometry of the human fetal small intestine is crucial for the adult gastroenterologist to appreciate, because of the potential for these early life events to affect the responsiveness of the intestine to physiological or pathological challenges in later life.


Assuntos
Desenvolvimento Fetal/fisiologia , Feto/citologia , Intestino Delgado/citologia , Morfogênese/fisiologia , Fatores Etários , Feminino , Idade Gestacional , Humanos , Índia , Masculino , Gravidez
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