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1.
Sleep Biol Rhythms ; 22(3): 411-421, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38962788

RESUMO

Infectious challenge can trigger alterations in sleep-wake behavior. Accumulating evidence has shown that the serine/threonine kinases Akt1 and Akt2 are important targets in both physiological and infectious signaling processes. However, the involvement of Akt1 and Akt2 in sleep-wake activity under basal conditions and in response to inflammatory stimulation has not been established. In the present study, we assessed the precise role of Akt1 and Akt2 in sleep-wake behavior using electroencephalography (EEG)/electromyography (EMG) data from Akt1- and Akt2-deficient mice and wild-type (WT) mice. The results showed that both Akt1 and Akt2 deficiency affect sleep-wake activity, as indicated by reduced nonrapid eye movement (NREM) sleep and increased wakefulness in mutant mice compared to WT mice. Sleep amount and intensity (delta, theta and alpha activity) at night were also drastically attenuated in Akt1- and Akt2-deficient mice. Moreover, since Akt1 and Akt2 are involved in immune responses, we assessed their roles in the sleep response to the inflammatory stimulus lipopolysaccharide (LPS) throughout the following 24 h. We observed that the decrease in wakefulness and increase in NREM sleep induced by LPS were restored in Akt1 knockout mice but not in Akt2 knockout mice. Correspondingly, the decrease in the number of positive orexin-A neurons induced by LPS was abrogated in Akt1 knockout mice but not in Akt2 knockout mice. Our results revealed that both Akt1 and Akt2 deficiency affect the sleep response under basal conditions, but only Akt1 deficiency protects against the aberrant changes in sleep behavior induced by peripheral immune challenge. Supplementary Information: The online version contains supplementary material available at 10.1007/s41105-024-00519-y.

2.
Curr Top Dev Biol ; 160: 1-30, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38937029

RESUMO

The salivary gland undergoes branching morphogenesis to elaborate into a tree-like structure with numerous saliva-secreting acinar units, all joined by a hierarchical ductal system. The expansive epithelial surface generated by branching morphogenesis serves as the structural basis for the efficient production and delivery of saliva. Here, we elucidate the process of salivary gland morphogenesis, emphasizing the role of mechanics. Structurally, the developing salivary gland is characterized by a stratified epithelium tightly encased by the basement membrane, which is in turn surrounded by a mesenchyme consisting of a dense network of interstitial matrix and mesenchymal cells. Diverse cell types and extracellular matrices bestow this developing organ with organized, yet spatially varied mechanical properties. For instance, the surface epithelial sheet of the bud is highly fluidic due to its high cell motility and weak cell-cell adhesion, rendering it highly pliable. In contrast, the inner core of the bud is more rigid, characterized by reduced cell motility and strong cell-cell adhesion, which likely provide structural support for the tissue. The interactions between the surface epithelial sheet and the inner core give rise to budding morphogenesis. Furthermore, the basement membrane and the mesenchyme offer mechanical constraints that could play a pivotal role in determining the higher-order architecture of a fully mature salivary gland.


Assuntos
Morfogênese , Glândulas Salivares , Glândulas Salivares/embriologia , Glândulas Salivares/citologia , Glândulas Salivares/metabolismo , Animais , Humanos , Membrana Basal/metabolismo , Movimento Celular , Fenômenos Biomecânicos , Mesoderma/citologia , Mesoderma/embriologia , Mesoderma/metabolismo , Adesão Celular
3.
EMBO Rep ; 25(6): 2698-2721, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38744971

RESUMO

Centrioles organize centrosomes, the cell's primary microtubule-organizing centers (MTOCs). Centrioles double in number each cell cycle, and mis-regulation of this process is linked to diseases such as cancer and microcephaly. In C. elegans, centriole assembly is controlled by the Plk4 related-kinase ZYG-1, which recruits the SAS-5-SAS-6 complex. While the kinase activity of ZYG-1 is required for centriole assembly, how it functions has not been established. Here we report that ZYG-1 physically interacts with and phosphorylates SAS-5 on 17 conserved serine and threonine residues in vitro. Mutational scanning reveals that serine 10 and serines 331/338/340 are indispensable for proper centriole assembly. Embryos expressing SAS-5S10A exhibit centriole assembly failure, while those expressing SAS-5S331/338/340A possess extra centrioles. We show that in the absence of serine 10 phosphorylation, the SAS-5-SAS-6 complex is recruited to centrioles, but is not stably incorporated, possibly due to a failure to coordinately recruit the microtubule-binding protein SAS-4. Our work defines the critical role of phosphorylation during centriole assembly and reveals that ZYG-1 might play a role in preventing the formation of excess centrioles.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Proteínas de Ciclo Celular , Centríolos , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Centríolos/metabolismo , Fosforilação , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Animais , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Ligação Proteica , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Serina/metabolismo , Sequência de Aminoácidos , Proteínas Quinases
4.
bioRxiv ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38766047

RESUMO

All multicellular systems produce and dynamically regulate extracellular matrices (ECM) that play important roles in both biochemical and mechanical signaling. Though the spatial arrangement of these extracellular assemblies is critical to their biological functions, visualization of ECM structure is challenging, in part because the biomolecules that compose the ECM are difficult to fluorescently label individually and collectively. Here, we present a cell-impermeable small molecule fluorophore, termed Rhobo6, that turns on and red shifts upon reversible binding to glycans. Given that most ECM components are densely glycosylated, the dye enables wash-free visualization of ECM, in systems ranging from in vitro substrates to in vivo mouse mammary tumors. Relative to existing techniques, Rhobo6 provides a broad substrate profile, superior tissue penetration, nonperturbative labeling, and negligible photobleaching. This work establishes a straightforward method for imaging the distribution of ECM in live tissues and organisms, lowering barriers for investigation of extracellular biology.

5.
Cells Dev ; 177: 203898, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38103869

RESUMO

The basement membrane (BM) demarcating epithelial tissues undergoes rapid expansion to accommodate tissue growth and morphogenesis during embryonic development. To facilitate the secretion of bulky BM proteins, their mRNAs are polarized basally in the follicle epithelial cells of the Drosophila egg chamber to position their sites of production close to their deposition. In contrast, we observed the apical rather than basal polarization of all major BM mRNAs in the outer epithelial cells adjacent to the BM of mouse embryonic salivary glands using single-molecule RNA fluorescence in situ hybridization (smFISH). Moreover, electron microscopy and immunofluorescence revealed apical polarization of both the endoplasmic reticulum (ER) and Golgi apparatus, indicating that the site of BM component production was opposite to the site of deposition. At the apical side, BM mRNAs colocalized with ER, suggesting they may be co-translationally tethered. After microtubule inhibition, the BM mRNAs and ER became uniformly distributed rather than apically polarized, but they remained unchanged after inhibiting myosin II, ROCK, or F-actin, or after enzymatic disruption of the BM. Because Rab6 is generally required for Golgi-to-plasma membrane trafficking of BM components, we used lentivirus to express an mScarlet-tagged Rab6a in salivary gland epithelial cultures to visualize vesicle trafficking dynamics. We observed extensive bidirectional vesicle movements between Golgi at the apical side and the basal plasma membrane adjacent to the BM. Moreover, we showed that these vesicle movements depend on the microtubule motor kinesin-1 because very few vesicles remained motile after treatment with kinesore to compete for cargo-binding sites on kinesin-1. Overall, our work highlights the diverse strategies that different organisms use to secrete bulky matrix proteins: while Drosophila follicle epithelial cells strategically place their sites of BM protein production close to their deposition, mouse embryonic epithelial cells place their sites of production at the opposite end. Instead of spatial proximity, they use the microtubule cytoskeleton to mediate this organization as well as for the apical-to-basal transport of BM proteins.


Assuntos
Cinesinas , Microtúbulos , Animais , Camundongos , Membrana Basal/metabolismo , Cinesinas/genética , Cinesinas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Hibridização in Situ Fluorescente , Microtúbulos/genética , Células Epiteliais/metabolismo , Drosophila/genética , Drosophila/metabolismo , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo
6.
Annu Rev Cell Dev Biol ; 39: 123-144, 2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37315160

RESUMO

Multicellular organisms generate tissues of diverse shapes and functions from cells and extracellular matrices. Their adhesion molecules mediate cell-cell and cell-matrix interactions, which not only play crucial roles in maintaining tissue integrity but also serve as key regulators of tissue morphogenesis. Cells constantly probe their environment to make decisions: They integrate chemical and mechanical information from the environment via diffusible ligand- or adhesion-based signaling to decide whether to release specific signaling molecules or enzymes, to divide or differentiate, to move away or stay, or even whether to live or die. These decisions in turn modify their environment, including the chemical nature and mechanical properties of the extracellular matrix. Tissue morphology is the physical manifestation of the remodeling of cells and matrices by their historical biochemical and biophysical landscapes. We review our understanding of matrix and adhesion molecules in tissue morphogenesis, with an emphasis on key physical interactions that drive morphogenesis.

7.
Curr Protoc ; 3(5): e772, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37222511

RESUMO

CRISPR-Cas9 has become a powerful and popular gene editing tool. However, successful application of this tool in the lab can still be quite daunting to many newcomers to molecular biology, mostly because it is a relatively lengthy process involving multiple steps with variations of each step. Here, we provide a reliable, stepwise, and newcomer-friendly protocol to knock out a target gene in wild-type human fibroblasts. This protocol involves sgRNA design using CRISPOR, construction of an "all-in-one" vector expressing both sgRNA and Cas9 using Golden Gate cloning, streamlined production of high-titer lentiviruses in 1 week after molecular cloning, and transduction of cells to generate a knockout cell pool. We further introduce a protocol for lentiviral transduction of ex vivo mouse embryonic salivary epithelial explants. In summary, our protocol is useful for new researchers to apply CRISPR-Cas9 to generate stable gene knockout cells and tissue explants using lentivirus. Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Basic Protocol 1: sgRNA design Basic Protocol 2: Cloning sgRNA in plasmid vector containing Cas9 encoding sequence using golden gate cloning Basic Protocol 3: Lentivirus packaging Basic Protocol 4: Lentivirus transduction of cells Basic Protocol 5: Lentivirus transduction of salivary gland epithelial buds.


Assuntos
Traumatismos Craniocerebrais , Lentivirus , Humanos , Animais , Camundongos , Camundongos Knockout , Lentivirus/genética , Sistemas CRISPR-Cas/genética , Técnicas de Inativação de Genes , Clonagem Molecular
8.
Anat Cell Biol ; 56(1): 46-53, 2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-36245240

RESUMO

It is unclear whether forearm and crural muscle fibers extend distally across the wrist and ankle joints, respectively. We hypothesized, in late-term fetuses, an over-production of muscle bellies extending over the joint. Muscle fibers in histological sections from unilateral wrists and ankles of 16 late-term fetuses (30-40 weeks) were examined and compared with 15 adult cadavers. Muscle fibers of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) in fetuses, especially muscle bellies to the third and fourth fingers, were found to extend far distally beyond the radiocarpal joint. The extensor digitorum and extensor pollicis longus on the extensor side of the wrist were found to carry distally-extending muscle fibers, but these fibers did not extend beyond the distal end of the radius. In the ankle, most muscle bundles in the flexor hallucis longus (FHL), fibularis brevis (FB) and extensor digitorum longus extended distally beyond the talocrural joint, with most FB muscle fibers reaching the level of the talocalcaneal joint. In adult cadavers, muscle fibers of the FDP and FHL did not reach the levels of the radiocarpal and talocrural joints, respectively, whereas the FB muscle belly always reached the talocalcaneal joint. Similarly, some of the FDS reached the level of the radiocarpal joint. Generally, infants' movements at the wrist and ankle could result in friction injury to over-extended muscle. However, the calcaneal and FDP tendons might protect the FB and FDS tendons, respectively, from friction stress.

9.
Cell ; 184(14): 3702-3716.e30, 2021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34133940

RESUMO

Many embryonic organs undergo epithelial morphogenesis to form tree-like hierarchical structures. However, it remains unclear what drives the budding and branching of stratified epithelia, such as in the embryonic salivary gland and pancreas. Here, we performed live-organ imaging of mouse embryonic salivary glands at single-cell resolution to reveal that budding morphogenesis is driven by expansion and folding of a distinct epithelial surface cell sheet characterized by strong cell-matrix adhesions and weak cell-cell adhesions. Profiling of single-cell transcriptomes of this epithelium revealed spatial patterns of transcription underlying these cell adhesion differences. We then synthetically reconstituted budding morphogenesis by experimentally suppressing E-cadherin expression and inducing basement membrane formation in 3D spheroid cultures of engineered cells, which required ß1-integrin-mediated cell-matrix adhesion for successful budding. Thus, stratified epithelial budding, the key first step of branching morphogenesis, is driven by an overall combination of strong cell-matrix adhesion and weak cell-cell adhesion by peripheral epithelial cells.


Assuntos
Junções Célula-Matriz/metabolismo , Morfogênese , Animais , Membrana Basal/metabolismo , Adesão Celular , Divisão Celular , Movimento Celular , Rastreamento de Células , Embrião de Mamíferos/citologia , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Epitélio , Regulação da Expressão Gênica no Desenvolvimento , Células HEK293 , Humanos , Integrinas/metabolismo , Camundongos , Modelos Biológicos , Glândulas Salivares/citologia , Glândulas Salivares/embriologia , Glândulas Salivares/metabolismo , Transcriptoma/genética
10.
BMC Gastroenterol ; 21(1): 138, 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33771126

RESUMO

BACKGROUND: Laparoscopic anatomic hepatectomy (LAH) has gradually become a routine surgical procedure. However, how to expose the whole hepatic vein and avoid the hepatic vein laceration is still a challenge because of the caudate lobe, particularly in right hepatectomy. We adopted a dorsal approach combined with Glissionian appraoch to perform laparoscopic right anatomic hepatectomy (LRAH). METHODS: Twenty patients who underwent LRAH from January 2017 to November 2018 were retrospectively analysed. Of these patients, seven patients underwent laparoscopic right hemihepatectomy (LRH group), seven patients who underwent laparoscopic right posterior hepatectomy (LRPH group), and six patients who underwent laparoscopic hepatectomy for segment 7 (LS7 group). The paracaval portion of caudate lobe could be transected firstly through dorsal approach and the corresponding major hepatic vein could be exposed from its root to the peripheral branches safely. Due to exposure along the major hepatic vein trunk, the remaining liver parenchyma could be quickly transected from dorsal to cranial side. RESULTS: The mean age of the patients was 53.8 years and the male: female ratio was 8:12. The median operation time was 306.0 ± 58.2 min and the mean estimated volume of blood loss was 412.5 ± 255.4 mL. The mean duration of postoperative hospital stay was 10.2 days. The mean Pringle maneuver time was 64.8 ± 27.7 min. Five patients received transfusion of 2-4 U of red blood cells. Two patients suffered from transient hepatic dysfunction and one suffered from pleural effusion. None of the patients underwent conversion to an open procedure. The operative duration, volume of the blood loss, Pringle maneuver time, and postoperative hospital stay duration did not differ significantly among the LRH, LRPH, and LS7 groups (P > 0.05). CONCLUSIONS: Dorsal approach combined with Glissonian approach for right lobe is feasible and effective in laparoscopic right anatomic liver resections.


Assuntos
Laparoscopia , Neoplasias Hepáticas , Feminino , Hepatectomia/efeitos adversos , Humanos , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Estudos Retrospectivos
11.
J Cell Biol ; 220(2)2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33399854

RESUMO

Centrosomes are composed of a centriolar core surrounded by a pericentriolar material (PCM) matrix that docks microtubule-nucleating γ-tubulin complexes. During mitotic entry, the PCM matrix increases in size and nucleating capacity in a process called centrosome maturation. Polo-like kinase 1 (PLK1) is recruited to centrosomes and phosphorylates PCM matrix proteins to drive their self-assembly, which leads to PCM expansion. Here, we show that in addition to controlling PCM expansion, PLK1 independently controls the generation of binding sites for γ-tubulin complexes on the PCM matrix. Selectively preventing the generation of PLK1-dependent γ-tubulin docking sites led to spindle defects and impaired chromosome segregation without affecting PCM expansion, highlighting the importance of phospho-regulated centrosomal γ-tubulin docking sites in spindle assembly. Inhibiting both γ-tubulin docking and PCM expansion by mutating substrate target sites recapitulated the effects of loss of centrosomal PLK1 on the ability of centrosomes to catalyze spindle assembly.


Assuntos
Caenorhabditis elegans/metabolismo , Centrossomo/metabolismo , Microtúbulos/metabolismo , Animais , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Ciclo Celular/metabolismo , Mitose , Fosforilação , Ligação Proteica , Proteínas Serina-Treonina Quinases , Fuso Acromático/metabolismo , Transgenes , Tubulina (Proteína)/metabolismo
13.
Medicine (Baltimore) ; 99(13): e19539, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32221073

RESUMO

Gallbladder occupying lesions are common diseases of biliary system. Among them, gallbladder cancer is difficult to diagnose due to the indistinguishable early symptoms, thus posing a great risk to the population. This study aims to establish a computed tomography (CT) prediction model for distinguishing benign and malignant lesions of gallbladder occupying lesions.The study included 211 patients with benign or malignant gallbladder occupying lesions who have taken resection in the Nanjing Drum Tower Hospital from January 2009 to December 2017. Clinical data collected includes age and sex; CT data includes tumor location, tumor maximum diameter, tumor form, venous phase portal venous CT value, abdominal aortic CT value, plain phase CT value, arterial phase CT value, venous phase CT value, delayed phase CT value, ΔCT1, ΔCT2, ΔCT3, ΔCT4, ΔCT5, ΔCT6, and ΔCT7. Calculation of odds ratio between benign and malignant gallbladder occupying lesions using single factor screening variables and multivariate logistic regression was done to establish a model and calculate the areas under receiver operating characteristic curves of the model.Multivariate logistic regression analysis showed that age, tumor maximum diameter, tumor form, venous phase portal venous CT value, ΔCT2, ΔCT4, and ΔCT6 are the main characteristic index for differential diagnosis of benign and malignant risk of gallbladder occupying lesions.Patients' age, tumor maximum diameter, tumor form, venous phase portal venous CT value, ΔCT2, ΔCT4, and ΔCT6 are independent risk factors for judging the benign and malignant of gallbladder occupying lesions. The model established exhibited a potential diagnostic value for distinguishing the malignant properties of gallbladder occupying lesions.


Assuntos
Doenças da Vesícula Biliar/diagnóstico por imagem , Doenças da Vesícula Biliar/patologia , Tomografia Computadorizada por Raios X/métodos , Adulto , Fatores Etários , Idoso , Meios de Contraste , Diagnóstico Diferencial , Feminino , Doenças da Vesícula Biliar/diagnóstico , Neoplasias da Vesícula Biliar/diagnóstico por imagem , Neoplasias da Vesícula Biliar/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Fatores Sexuais , Carga Tumoral
14.
Dev Cell ; 52(5): 631-646.e4, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32004443

RESUMO

We have discovered that basement membrane and its major components can induce rapid, strikingly robust fibronectin organization. In this new matrix assembly mechanism, α5ß1 integrin-based focal adhesions slide actively on the underlying matrix toward the ventral cell center through the dynamic shortening of myosin IIA-associated actin stress fibers to drive rapid fibronectin fibrillogenesis distal to the adhesion. This mechanism contrasts with classical fibronectin assembly based on stable or fixed-position focal adhesions containing αVß3 integrins plus α5ß1 integrin translocation into proximal fibrillar adhesions. On basement membrane components, these sliding focal adhesions contain standard focal adhesion constituents but completely lack classical αVß3 integrins. Instead, peripheral α3ß1 or α2ß1 adhesions mediate initial cell attachment but over time are switched to α5ß1 integrin-based sliding focal adhesions to assemble fibronectin matrix. This basement-membrane-triggered mechanism produces rapid fibronectin fibrillogenesis, providing a mechanistic explanation for the well-known widespread accumulation of fibronectin at many organ basement membranes.


Assuntos
Actomiosina/metabolismo , Membrana Basal/metabolismo , Fibronectinas/metabolismo , Adesões Focais/metabolismo , Multimerização Proteica , Animais , Linhagem Celular Tumoral , Células Cultivadas , Humanos , Integrinas/metabolismo , Camundongos , Movimento (Física) , Células NIH 3T3
15.
BMC Gastroenterol ; 19(1): 194, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752706

RESUMO

BACKGROUND: Although isolating Glissonean pedicles and hepatic veins are critical procedures during anatomical hepatectomy, there is no standardized approach. We propose the novel Laennec's approach for laparoscopic anatomic hepatectomy (LAH) based on Laennec's capsule, which serves as the anatomic landmark for LAH. The aim of this study was to elucidate that the natural gap between Laennec's capsule and the adjacent tissues contributes to standardization of the surgical technique for LAH. METHODS: Eighty-four cases were enrolled in this observable clinical trial. They underwent LAH for liver diseases. Laennec's approach was proposed for LAH based on Laennec's capsule. The liver tissues close to Glissonean pedicle, hepatic veins, naked area, and inferior vena cava were collected for hematoxylin and eosin, resorcinol-fuchsin staining, and immunohistochemistry. RESULTS: The staining revealed capsule packaging of the whole liver independent of the adjacent tissues and intrahepatic vessels. A natural gap was found between Laennec's capsule and the adjacent tissues at different sites. Laennec's capsule served as the landmark for isolating Glissonean pedicle and hepatic veins, mobilizing the liver, and performing Hanging maneuver. Eighty-four cases underwent LAH for liver diseases using this strategy. The operation time was 277.23 min. The mean of hospital days was 9.8. CONCLUSIONS: Laennec's approach based on Laennec's capsule contributes to standardization of the surgical technique for LAH, and brings innovations that facilitates safe and effective liver resection under laparoscopy.


Assuntos
Pontos de Referência Anatômicos , Hepatectomia/métodos , Laparoscopia/métodos , Fígado/anatomia & histologia , Carcinoma Hepatocelular/cirurgia , Feminino , Hepatectomia/efeitos adversos , Humanos , Laparoscopia/efeitos adversos , Tempo de Internação , Litíase/cirurgia , Fígado/cirurgia , Hepatopatias/cirurgia , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Complicações Pós-Operatórias
16.
J Vis Exp ; (152)2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31736498

RESUMO

C. elegans is the premier system for the systematic analysis of cell fate specification and morphogenetic events during embryonic development. One challenge is that embryogenesis dynamically unfolds over a period of about 13 h; this half day-long timescale has constrained the scope of experiments by limiting the number of embryos that can be imaged. Here, we describe a semi-high-throughput protocol that allows for the simultaneous 3D time-lapse imaging of development in 80-100 embryos at moderate time resolution, from up to 14 different conditions, in a single overnight run. The protocol is straightforward and can be implemented by any laboratory with access to a microscope with point visiting capacity. The utility of this protocol is demonstrated by using it to image two custom-built strains expressing fluorescent markers optimized to visualize key aspects of germ-layer specification and morphogenesis. To analyze the data, a custom program that crops individual embryos out of a broader field of view in all channels, z-steps, and timepoints and saves the sequences for each embryo into a separate tiff stack was built. The program, which includes a user-friendly graphical user interface (GUI), streamlines data processing by isolating, pre-processing, and uniformly orienting individual embryos in preparation for visualization or automated analysis. Also supplied is an ImageJ macro that compiles individual embryo data into a multi-panel file that displays maximum intensity fluorescence projection and brightfield images for each embryo at each time point. The protocols and tools described herein were validated by using them to characterize embryonic development following knock-down of 40 previously described developmental genes; this analysis visualized previously annotated developmental phenotypes and revealed new ones. In summary, this work details a semi-high-throughput imaging method coupled with a cropping program and ImageJ visualization tool that, when combined with strains expressing informative fluorescent markers, greatly accelerates experiments to analyze embryonic development.


Assuntos
Caenorhabditis elegans/embriologia , Visualização de Dados , Embrião não Mamífero/citologia , Desenvolvimento Embrionário , Ensaios de Triagem em Larga Escala/métodos , Interpretação de Imagem Assistida por Computador/métodos , Morfogênese , Animais , Caenorhabditis elegans/fisiologia
17.
Int J Exp Pathol ; 100(3): 144-152, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31179622

RESUMO

This review describes how direct visualization of the dynamic interactions of cells with different extracellular matrix microenvironments can provide novel insights into complex biological processes. Recent studies have moved characterization of cell migration and invasion from classical 2D culture systems into 1D and 3D model systems, revealing multiple differences in mechanisms of cell adhesion, migration and signalling-even though cells in 3D can still display prominent focal adhesions. Myosin II restrains cell migration speed in 2D culture but is often essential for effective 3D migration. 3D cell migration modes can switch between lamellipodial, lobopodial and/or amoeboid depending on the local matrix environment. For example, "nuclear piston" migration can be switched off by local proteolysis, and proteolytic invadopodia can be induced by a high density of fibrillar matrix. Particularly, complex remodelling of both extracellular matrix and tissues occurs during morphogenesis. Extracellular matrix supports self-assembly of embryonic tissues, but it must also be locally actively remodelled. For example, surprisingly focal remodelling of the basement membrane occurs during branching morphogenesis-numerous tiny perforations generated by proteolysis and actomyosin contractility produce a microscopically porous, flexible basement membrane meshwork for tissue expansion. Cells extend highly active blebs or protrusions towards the surrounding mesenchyme through these perforations. Concurrently, the entire basement membrane undergoes translocation in a direction opposite to bud expansion. Underlying this slowly moving 2D basement membrane translocation are highly dynamic individual cell movements. We conclude this review by describing a variety of exciting research opportunities for discovering novel insights into cell-matrix interactions.


Assuntos
Membrana Basal/metabolismo , Movimento Celular/fisiologia , Matriz Extracelular/metabolismo , Morfogênese/fisiologia , Transdução de Sinais/fisiologia , Animais , Adesão Celular/fisiologia , Humanos
18.
Dev Cell ; 48(6): 864-872.e7, 2019 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-30827898

RESUMO

Dynamic coupling of microtubule ends to kinetochores, built on the centromeres of chromosomes, directs chromosome segregation during cell division. Here, we report that the evolutionarily ancient kinetochore-microtubule coupling machine, the KMN (Knl1/Mis12/Ndc80-complex) network, plays a critical role in neuronal morphogenesis. We show that the KMN network concentrates in microtubule-rich dendrites of developing sensory neurons that collectively extend in a multicellular morphogenetic event that occurs during C. elegans embryogenesis. Post-mitotic degradation of KMN components in sensory neurons disrupts dendritic extension, leading to patterning and functional defects in the sensory nervous system. Structure-guided mutations revealed that the molecular interface that couples kinetochores to spindle microtubules also functions in neuronal development. These results identify a cell-division-independent function for the chromosome-segregation machinery and define a microtubule-coupling-dependent event in sensory nervous system morphogenesis.


Assuntos
Cinetocoros/metabolismo , Microtúbulos/metabolismo , Morfogênese , Sistema Nervoso/embriologia , Sistema Nervoso/metabolismo , Células Receptoras Sensoriais/metabolismo , Animais , Caenorhabditis elegans/embriologia , Proteínas de Caenorhabditis elegans/metabolismo , Dendritos/metabolismo , Embrião não Mamífero/metabolismo , Desenvolvimento Embrionário , Mitose
19.
Development ; 146(7)2019 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-30890570

RESUMO

The Caenorhabditis elegans embryo is an important model for analyzing mechanisms of cell fate specification and tissue morphogenesis. Sophisticated lineage-tracing approaches for analyzing embryogenesis have been developed but are labor intensive and do not naturally integrate morphogenetic readouts. To enable the rapid classification of developmental phenotypes, we developed a high-content method that employs two custom strains: a Germ Layer strain that expresses nuclear markers in the ectoderm, mesoderm and endoderm/pharynx; and a Morphogenesis strain that expresses markers labeling epidermal cell junctions and the neuronal cell surface. We describe a procedure that allows simultaneous live imaging of development in 80-100 embryos and provide a custom program that generates cropped, oriented image stacks of individual embryos to facilitate analysis. We demonstrate the utility of our method by perturbing 40 previously characterized developmental genes in variants of the two strains containing RNAi-sensitizing mutations. The resulting datasets yielded distinct, reproducible signature phenotypes for a broad spectrum of genes that are involved in cell fate specification and morphogenesis. In addition, our analysis provides new in vivo evidence for MBK-2 function in mesoderm fate specification and LET-381 function in elongation.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/metabolismo , Animais , Proteínas de Caenorhabditis elegans/genética , Desenvolvimento Embrionário/genética , Desenvolvimento Embrionário/fisiologia , Endoderma/embriologia , Endoderma/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Mesoderma/embriologia , Mesoderma/metabolismo
20.
Curr Protoc Cell Biol ; 83(1): e79, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30394692

RESUMO

Single molecule RNA fluorescence in situ hybridization (smFISH) has become the standard tool for high spatial resolution analysis of gene expression in the context of tissue organization. This article describes protocols to perform smFISH on whole-mount mouse embryonic organs, where tissue organization can be compared to RNA expression by co-immunostaining of known protein markers. An enzymatic labeling strategy is also introduced to produce low-cost smFISH probes. Important considerations and practical guidelines for imaging smFISH samples using fluorescence confocal microscopy are described. Finally, a suite of custom-written ImageJ macros is included with detailed instructions to enable semi-automated smFISH image analysis of both 2D and 3D images. © 2018 by John Wiley & Sons, Inc.


Assuntos
Hibridização in Situ Fluorescente/métodos , Imagem Individual de Molécula , Animais , Embrião de Mamíferos , Perfilação da Expressão Gênica/métodos , Camundongos , RNA/análise
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