RESUMO
Formation of the skeletal structure in the human embryo has important consequences in terms of support, protection, and function of organs and other systems. We aimed to describe the formation of the rib cage during the embryonic period, in order to detect prominent features and identify the possible factors affecting rib cage morphology. We employed high-resolution digitized imaging data (n = 34) obtained in human embryos with Carnegie stage (CS) between 17 and 23. The rib cage became detectable as cartilage formation at CS17, expanding outward from the dorsal side of the chest-abdominal region. Ribs elongated progressively to surround the chest, differentiating into the upper and lower rib cage regions by CS20. The ends of corresponding ribs in the upper region elongated toward each other, leading to their joining and sternum formation between CS21 and CS23, while the lower region of the rib cage remained widely open. The rib cage area with the largest width shifted from the 5th rib pair at CS17 to the 9th pair at CS23. The depth of the rib cage was similar across the upper region at CS17, with the major portion remaining in the middle part after CS20. The heart was located beneath the rib pairs providing the largest depth, while the liver was located beneath the rib pairs providing the largest width. Formation of the sternum, development of spinal kyphosis, and organization of larger internal organs within the thoracic and abdominal cavity are possible factors affecting rib cage morphology. Anat Rec, 302:2211-2223, 2019. © 2019 American Association for Anatomy.
Assuntos
Embrião de Mamíferos/citologia , Morfogênese , Caixa Torácica/citologia , Costelas/citologia , Tórax/citologia , Humanos , Imageamento TridimensionalRESUMO
Noninvasive monitoring of cardiac hemodynamics remains challenging in cardiovascular medicine. The possibility of noninvasive optical monitoring of cardiac hemodynamics was theoretically investigated in this study. By utilizing the Monte Carlo simulation method for voxelized media (MCVM) and Visible Chinese Human dataset, we quantified and visualized the photon migration in human thoracic region. The light fluence distribution was showed to reach heart tissue (â¼3 cm depth underbody surface) and 12% of the total fluence was absorbed by the myocardium. The proportion of spatial sensitivity distribution (SSD) in cardiac tissue to the total SSD reached 0.0195%. The portion of SSD increased following with cardiac diastole and diffuse reflectance deceased linearly with increasing cardiac volume. The optimal separation between the light source and detector was provided to be 3.5 to 4.0 cm for future development of noninvasive cardiac hemodynamics monitoring. A pilot experimental study was conducted to measure the diffuse reflectance light and fingertip photoplethysmography. These data suggest that the fluctuation period of near-infrared (NIR) diffuse reflectance was consistent with the cardiac cycle, while the fluctuation features of the NIR signal was not consistent with that of photoplethysmography. All results indicate the great potential of noninvasive optical monitoring of myocardial hemodynamics.
Assuntos
Coração/fisiologia , Hemodinâmica , Método de Monte Carlo , Fenômenos Ópticos , Fótons , Tórax/citologia , Humanos , Processamento de Imagem Assistida por Computador , Modelos BiológicosRESUMO
Tissue closure involves the coordinated unidirectional movement of a group of cells without loss of cell-cell contact. However, the molecular mechanisms controlling the tissue closure are not fully understood. Here, we demonstrate that Lamin C, the sole A-type lamin in Drosophila, contributes to the process of thorax closure in pupa. High expression of Lamin C was observed at the leading front of the migrating wing imaginal discs. Live imaging analysis revealed that knockdown of Lamin C in the thorax region affected the coordinated movement of the leading front, resulting in incomplete tissue fusion required for formation of the adult thorax. The closure defect due to knockdown of Lamin C correlated with insufficient accumulation of F-actin at the front. Our study indicates a link between A-type lamin and the cell migration behavior during tissue closure.
Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/embriologia , Drosophila melanogaster/metabolismo , Lamina Tipo A/metabolismo , Laminas/metabolismo , Tórax/embriologia , Actinas/metabolismo , Animais , Movimento Celular , Proteínas de Drosophila/genética , Drosophila melanogaster/citologia , Técnicas de Silenciamento de Genes , Laminas/genética , Tórax/citologiaRESUMO
Solitary ï¬brous tumors are mesenchymal lesions that arise at a variety of sites, most commonly the pleura. Most patients are asymptomatic at diagnosis, with lesions being detected incidentally. Nevertheless, some patients present due to symptoms from local tumor compression (eg. of the airways and pulmonary parenchyma). Furthermore, radiological methods are not always conclusive in making a diagnosis, and thus, pathological analysis is often required. In the past three decades, immunohistochemical techniques have provided a gold standard in solitary ï¬brous tumor diagnosis. The signature marker of solitary ï¬brous tumor is the presence of the NAB2-STAT6 fusion that can be reliably detected with a STAT6 antibody. While solitary ï¬brous tumors are most often benign, they can be malignant in 10-20% of the cases. Unfortunately, histological parameters are not always predictive of benign vs malignant solitary ï¬brous tumors. As solitary ï¬brous tumors are generally regarded as relatively chemoresistant tumors; treatment is often limited to localized treatment modalities. The optimal treatment of solitary ï¬brous tumors appears to be complete surgical resection for both primary and local recurrent disease. However, in cases of suboptimal resection, large disease burden, or advanced recurrence, a multidisciplinary approach may be preferable. Specifically, radiotherapy for inoperable local disease can provide palliation/shrinkage. Given their sometimes -unpredictable and often- protracted clinical course, long-term follow-up post-resection is recommended.
Assuntos
Tumores Fibrosos Solitários/diagnóstico , Tumores Fibrosos Solitários/terapia , Tórax/fisiopatologia , Biomarcadores Tumorais/análise , Tratamento Farmacológico/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Radioterapia/métodos , Tumores Fibrosos Solitários/fisiopatologia , Tórax/citologia , Tomografia Computadorizada por Raios X/métodosRESUMO
The proto-oncogene Myc is well known for its roles in promoting cell growth, proliferation and apoptosis. However, in this study, we found from a genetic screen that Myc inhibits, rather than promotes, cell death triggered by c-Jun N-terminal kinase (JNK) signaling in Drosophila. Firstly, expression of Drosophila Myc (dMyc) suppresses, whereas loss of dMyc enhances, ectopically activated JNK signaling-induced cell death. Secondly, dMyc impedes physiologically activated JNK pathway-mediated cell death. Thirdly, loss of dMyc triggers JNK pathway activation and JNK-dependent cell death. Finally, the mammalian cMyc gene, when expressed in Drosophila, impedes activated JNK signaling-induced cell death. Thus, besides its well-studied apoptosis promoting function, Myc also antagonizes JNK-mediated cell death in Drosophila, and this function is likely conserved from fly to human.
Assuntos
Apoptose/genética , Proteínas de Ligação a DNA/fisiologia , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/genética , Genes myc , Sistema de Sinalização das MAP Quinases/genética , Fatores de Transcrição/fisiologia , Animais , Olho Composto de Artrópodes/citologia , Olho Composto de Artrópodes/embriologia , Olho Composto de Artrópodes/crescimento & desenvolvimento , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/genética , Drosophila melanogaster/citologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Genes Sintéticos , Humanos , Larva , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , Morfogênese , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/fisiologia , Proteínas Recombinantes de Fusão/metabolismo , Especificidade da Espécie , Tórax/citologia , Tórax/embriologia , Tórax/crescimento & desenvolvimento , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Asas de Animais/citologia , Asas de Animais/embriologia , Asas de Animais/crescimento & desenvolvimentoRESUMO
The numbers and types of progeny cells generated by neural stem cells in the developing CNS are adapted to its region-specific functional requirements. In Drosophila, segmental units of the CNS develop from well-defined patterns of neuroblasts. Here we constructed comprehensive neuroblast maps for the three gnathal head segments. Based on the spatiotemporal pattern of neuroblast formation and the expression profiles of 46 marker genes (41 transcription factors), each neuroblast can be uniquely identified. Compared with the thoracic ground state, neuroblast numbers are progressively reduced in labial, maxillary and mandibular segments due to smaller sizes of neuroectodermal anlagen and, partially, to suppression of neuroblast formation and induction of programmed cell death by the Hox gene Deformed Neuroblast patterns are further influenced by segmental modifications in dorsoventral and proneural gene expression. With the previously published neuroblast maps and those presented here for the gnathal region, all neuroectodermal neuroblasts building the CNS of the fly (ventral nerve cord and brain, except optic lobes) are now individually identified (in total 2×567 neuroblasts). This allows, for the first time, a comparison of the characteristics of segmental populations of stem cells and to screen for serially homologous neuroblasts throughout the CNS. We show that approximately half of the deutocerebral and all of the tritocerebral (posterior brain) and gnathal neuroblasts, but none of the protocerebral (anterior brain) neuroblasts, display serial homology to neuroblasts in thoracic/abdominal neuromeres. Modifications in the molecular signature of serially homologous neuroblasts are likely to determine the segment-specific characteristics of their lineages.
Assuntos
Sistema Nervoso Central/embriologia , Drosophila melanogaster/embriologia , Células-Tronco Neurais/metabolismo , Transcriptoma , Abdome/embriologia , Animais , Contagem de Células , Linhagem da Célula , Sistema Nervoso Central/citologia , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Genes de Insetos , Marcadores Genéticos , Células-Tronco Neurais/citologia , Tórax/citologia , Tórax/embriologiaRESUMO
BACKGROUND: Human thoracic brown adipose tissue (BAT), composed of several subdivisions, is a well-known target organ of many clinical studies; however, the functional contribution of each part of human thoracic BAT remains unknown. The present study analyzed the significance of each part of human thoracic BAT in the association between regional distribution, cellularity, and factors involved in the functional regulation of thoracic BAT. METHODS: We analyzed 1550 healthy adults who underwent medical check-ups by positron-emission tomography and computed tomography (PET-CT) imaging, 8 cadavers, and 78 autopsy cases in an observational study. We first characterized the difference between the mediastinum and the supraclavicular areas using counts of BAT detection and conditions based on PET-CT outcomes. The measurable important area was then subjected to systematic anatomical and immunohistochemical analyses using anti-uncoupling protein 1 (UCP1) antibody to characterize the cellularity in association with age and sex. RESULTS: In PET-CT scanning, the main site of thoracic BAT was the mediastinum rather than the supraclavicular area (P < 0.05). Systemic macroanatomy revealed that the thumb-sized BAT in the posterior mediastinal descending para-aortic area (paBAT) had feeding vessels from the posterior intercostal arteries and veins and sympathetic/parasympathetic innervation from trunks of the sympathetic and vagus nerves, respectively. Immunohistochemical analysis indicated that the paBAT exhibited immunoreactivity for tyrosine hydroxylase and vesicular acetylcholine transporter located in the pericellular nervous fibers and intracellular UCP1. The brown adipose cells of paBAT showed age-dependent decreases in UCP1 expression (P < 0.05), accompanied by a significant increase in vacuole formation, indicating fat accumulation (P < 0.05), from 10 to 37 years of age (P < 0.01). CONCLUSIONS: paBAT may be one of the essential sites for clinical application in BAT study because of its visible anatomy with feeding vessels and sympathetic/parasympathetic innervation functionally affected by outer condition and senescence.
Assuntos
Tecido Adiposo Marrom/diagnóstico por imagem , Glomos Para-Aórticos/diagnóstico por imagem , Radiografia Torácica , Tórax/metabolismo , Tecido Adiposo Marrom/citologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Autopsia , Cadáver , Criança , Feminino , Fluordesoxiglucose F18 , Humanos , Canais Iônicos/biossíntese , Masculino , Pessoa de Meia-Idade , Proteínas Mitocondriais/biossíntese , Glomos Para-Aórticos/citologia , Tomografia por Emissão de Pósitrons , Tórax/citologia , Proteína Desacopladora 1 , Vacúolos/metabolismoRESUMO
Chemoreception is a key feature in selection of host plants by insects. In this study, preliminary characterization and isolation of cDNA clones from Cnaphalocrocis medinalis antennal libraries identified eight olfactory genes, including two putative general odorant-binding proteins (GOBPs), three pheromone binding proteins (PBPs) and three chemosensory proteins (CSPs). The expression profiles of these eight genes in different tissues (antenna, head (without antennae), thorax, abdomen, leg and wing) were measured by real time qPCR. The results showed that GOBP and PBP genes in C. medinalis seemed to be antenna-specific, but differentially expressed in male and female antennae; while CSP genes were expressed ubiquitously during different developmental stages, but with an extremely elevated transcript level in antennae, legs and wings compared to head, thorax and abdomen. And also, the transcription levels of olfactory genes depended on the age, sex, and mating status of the adults. These findings support the hypothesis that OBPs and CSPs play dynamic roles during development of C. medinalis and are likely to be involved in broader physiological functions.
Assuntos
Antenas de Artrópodes/citologia , Regulação da Expressão Gênica no Desenvolvimento , Genes de Insetos , Mariposas/genética , Sequência de Aminoácidos , Animais , Antenas de Artrópodes/metabolismo , Clonagem Molecular , Biologia Computacional , Feminino , Biblioteca Gênica , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/citologia , Larva/genética , Larva/crescimento & desenvolvimento , Masculino , Dados de Sequência Molecular , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Especificidade de Órgãos , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Alinhamento de Sequência , Fatores Sexuais , Tórax/citologia , Tórax/metabolismo , Transcrição Gênica , Transcriptoma , Asas de Animais/citologia , Asas de Animais/metabolismoRESUMO
How adhesive contacts with neighbors may affect epithelial cell cytokinesis is unknown. We report that in Drosophila, septins are specifically required for planar (but not orthogonal) cytokinesis. During planar division, cytokinetic furrowing initiates basally, resulting in a contractile ring displaced toward the adherens junction (AJ). The formation of new AJ between daughter cells requires the disengagement of E-Cadherin complexes between mitotic and neighboring cells at the cleavage furrow, followed by the assembly of E-Cadherin complexes on the daughter-daughter interface. The strength of adhesion with neighbors directly impacts both the kinetics of AJ disengagement and the length of the new AJ. Loss of septins causes a reduction in the contractility of the actomyosin ring and prevents local disengagement of AJ in the cleavage furrow. By modulating the strength of tension induced by neighbors, we uncover a mechanical function for septins to overcome the extrinsic tension induced by neighboring interphasic cells.
Assuntos
Actomiosina , Junções Aderentes , Citocinese/genética , Septinas , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/metabolismo , Actomiosina/genética , Actomiosina/metabolismo , Junções Aderentes/genética , Junções Aderentes/fisiologia , Animais , Caderinas/genética , Caderinas/metabolismo , Adesão Celular/genética , Polaridade Celular , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Desenvolvimento Embrionário , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Contração Muscular/genética , Septinas/genética , Septinas/metabolismo , Tórax/citologia , Tórax/crescimento & desenvolvimentoRESUMO
How adherens junctions (AJs) are formed upon cell division is largely unexplored. Here, we found that AJ formation is coordinated with cytokinesis and relies on an interplay between the dividing cell and its neighbors. During contraction of the cytokinetic ring, the neighboring cells locally accumulate Myosin II and produce the cortical tension necessary to set the initial geometry of the daughter cell interface. However, the neighboring cell membranes impede AJ formation. Upon midbody formation and concomitantly to neighboring cell withdrawal, Arp2/3-dependent actin polymerization oriented by the midbody maintains AJ geometry and regulates AJ final length and the epithelial cell arrangement upon division. We propose that cytokinesis in epithelia is a multicellular process, whereby the cooperative actions of the dividing cell and its neighbors define a two-tiered mechanism that spatially and temporally controls AJ formation while maintaining tissue cohesiveness.
Assuntos
Junções Aderentes , Citocinese/genética , Epitélio/crescimento & desenvolvimento , Tórax , Citoesqueleto de Actina/metabolismo , Junções Aderentes/genética , Junções Aderentes/metabolismo , Animais , Caderinas/metabolismo , Adesão Celular/genética , Comunicação Celular/genética , Divisão Celular/genética , Linhagem Celular , Membrana Celular , Polaridade Celular , Drosophila melanogaster/genética , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Epitélio/metabolismo , Tórax/citologia , Tórax/crescimento & desenvolvimento , Tórax/metabolismoRESUMO
BACKGROUND: Sebaceous glands are components of the skin essential for its normal lubrication by the production of sebum. This contributes to skin health and more importantly is crucial for the skin barrier function. A mechanistic understanding of sebaceous gland cells growth and differentiation has lagged behind that for keratinocytes, partly because of a lack of an in vitro model that can be used for experimental manipulation. METHODS: We have developed an in vitro culture model to isolate and grow primary human sebocytes without transformation that display functional characteristics of sebocytes. We used this novel method to probe the effect of Transforming Growth Factor ß (TGFß) signaling on sebocyte differentiation, by examining the expression of genes involved in lipogenesis upon treatment with TGFß1. We also repressed TGFß signaling through knockdown of the TGFß Receptor II to address if the effect of TGFß activation is mediated via canonical Smad signal transduction. RESULTS: We find that activation of the TGFß signaling pathway is necessary and sufficient for maintaining sebocytes in an undifferentiated state. The presence of TGFß ligand triggered decreased expression in genes required for the production of characteristics sebaceous lipids and for sebocyte differentiation such as FADS2 and PPARγ, thereby decreasing lipid accumulation through the TGFß RII-Smad2 dependent pathway. CONCLUSION: TGFß signaling plays an essential role in sebaceous gland regulation by maintaining sebocytes in an undifferentiated state. This data was generated using a novel method for human sebocyte culture, which is likely to prove generally useful in investigations of sebaceous gland growth and differentiation. These findings open a new paradigm in human skin biology with important implications for skin therapies.
Assuntos
Técnicas de Cultura de Células/métodos , Lipogênese/fisiologia , Glândulas Sebáceas/citologia , Glândulas Sebáceas/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Mama/citologia , Diferenciação Celular , Células Cultivadas , Criança , Pré-Escolar , Face , Fibronectinas/metabolismo , Humanos , Lactente , Couro Cabeludo/citologia , Transdução de Sinais , Tórax/citologiaRESUMO
During animal development, several planar cell polarity (PCP) pathways control tissue shape by coordinating collective cell behavior. Here, we characterize by means of multiscale imaging epithelium morphogenesis in the Drosophila dorsal thorax and show how the Fat/Dachsous/Four-jointed PCP pathway controls morphogenesis. We found that the proto-cadherin Dachsous is polarized within a domain of its tissue-wide expression gradient. Furthermore, Dachsous polarizes the myosin Dachs, which in turn promotes anisotropy of junction tension. By combining physical modeling with quantitative image analyses, we determined that this tension anisotropy defines the pattern of local tissue contraction that contributes to shaping the epithelium mainly via oriented cell rearrangements. Our results establish how tissue planar polarization coordinates the local changes of cell mechanical properties to control tissue morphogenesis.
Assuntos
Caderinas/metabolismo , Moléculas de Adesão Celular/metabolismo , Polaridade Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crescimento & desenvolvimento , Glicoproteínas de Membrana/metabolismo , Morfogênese , Animais , Anisotropia , Caderinas/genética , Moléculas de Adesão Celular/genética , Forma Celular , Proteínas de Drosophila/genética , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Junções Intercelulares/metabolismo , Junções Intercelulares/fisiologia , Glicoproteínas de Membrana/genética , Metamorfose Biológica , Modelos Biológicos , Miosinas/metabolismo , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Tórax/citologia , Tórax/crescimento & desenvolvimento , Tórax/metabolismoRESUMO
PURPOSE: The main purpose of the present study was to determine the amounts of different tissues in the chest of the newborn patient (age ≤1 year), with the aim of developing a homogeneous phantom chest equivalent. This type of phantom is indispensable in the development of optimization procedures for radiographic techniques, including dosimetric control, which is a crucial aspect of pediatric radiology. The authors present a systematic set of procedures, including a computational algorithm, to estimate the amounts of tissues and thicknesses of the corresponding simulator material plates used to construct the phantom. METHODS: The Gaussian fit of computed tomographic (CT) analysis was applied to classify and quantify different biological tissues. The methodology is summarized with a computational algorithm, which was used to quantify tissues through automated CT analysis. The thicknesses of the equivalent homogeneous simulator material plates were determined to construct the phantom. RESULTS: A total of 180 retrospective CT examinations with anterior-posterior diameter values ranging 8.5-13.0 cm were examined. The amounts of different tissues were evaluated. The results provided elements to construct a phantom to simulate the infant chest in the posterior-anterior or anterior-posterior (PA/AP) view. CONCLUSIONS: To our knowledge, this report represents the first demonstration of an infant chest phantom dedicated to the radiology of children younger than one year. This phantom is a key element in the development of clinical charts for optimizing radiographic technique in pediatric patients. Optimization procedures for nonstandard patients were reported previously [Pina et al., Phys. Med. Biol. 49, N215-N226 (2004) and Pina et al., Appl. Radiat. Isot. 67, 61-69 (2009)]. The constructed phantom represents a starting point to obtain radiologic protocols for the infant patient.
Assuntos
Imagens de Fantasmas , Radiografia Torácica/instrumentação , Tórax/citologia , Humanos , LactenteRESUMO
Mesenchymal cells underlying the definitive endoderm in vertebrate animals play a vital role in digestive and respiratory organogenesis. Although several signaling pathways are implicated in foregut patterning and morphogenesis, and despite the clinical importance of congenital tracheal and esophageal malformations in humans, understanding of molecular mechanisms that allow a single tube to separate correctly into the trachea and esophagus is incomplete. The homoebox gene Barx1 is highly expressed in prospective stomach mesenchyme and required to specify this organ. We observed lower Barx1 expression extending contiguously from the proximal stomach domain, along the dorsal anterior foregut mesenchyme and in mesenchymal cells between the nascent esophagus and trachea. This expression pattern exactly mirrors the decline in Wnt signaling activity in late development of the adjacent dorsal foregut endoderm and medial mainstem bronchi. The hypopharynx in Barx1(-/-) mouse embryos is abnormally elongated and the point of esophago-tracheal separation shows marked caudal displacement, resulting in a common foregut tube that is similar to human congenital tracheo-esophageal fistula and explains neonatal lethality. Moreover, the Barx1(-/-) esophagus displays molecular and cytologic features of respiratory endoderm, phenocopying abnormalities observed in mouse embryos with activated ß-catenin. The zone of canonical Wnt signaling is abnormally prolonged and expanded in the proximal Barx1(-/-) foregut. Thus, as in the developing stomach, but distinct from the spleen, Barx1 control of thoracic foregut specification and tracheo-esophageal septation is tightly associated with down-regulation of adjacent Wnt pathway activity.
Assuntos
Diferenciação Celular , Células Epiteliais/citologia , Esôfago/embriologia , Proteínas de Homeodomínio/metabolismo , Tórax/embriologia , Traqueia/embriologia , Fatores de Transcrição/metabolismo , Proteínas Wnt/metabolismo , Animais , Endoderma/citologia , Endoderma/metabolismo , Células Epiteliais/metabolismo , Esôfago/citologia , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/genética , Masculino , Mesoderma/citologia , Mesoderma/metabolismo , Camundongos , Transdução de Sinais/genética , Tórax/anatomia & histologia , Tórax/citologia , Tórax/metabolismo , Traqueia/citologia , Fatores de Transcrição/deficiência , Fatores de Transcrição/genéticaRESUMO
Intravital microscopy has been recognized for its ability to make physiological measurements at cellular and subcellular levels while maintaining the complex natural microenvironment. Two-photon microscopy (TPM), using longer wavelengths than single-photon excitation, has extended intravital imaging deeper into tissues, with minimal phototoxicity. However, due to a relatively slow acquisition rate, TPM is especially sensitive to motion artifact, which presents a challenge when imaging tissues subject to respiratory and cardiac movement. Thoracoabdominal organs that cannot be exteriorized or immobilized during TPM have generally required the use of isolated, pump-perfused preparations. However, this approach entails significant alteration of normal physiology, such as a lack of neural inputs, increased vascular resistance, and leukocyte activation. We adapted techniques of intravital microscopy that permitted TPM of organs maintained within the thoracoabdominal cavity of living, breathing rats or mice. We obtained extended intravital TPM imaging of the intact lung, arguably the organ most susceptible to both respiratory and cardiac motion. Intravital TPM detected the development of lung microvascular endothelial activation manifested as increased leukocyte adhesion and plasma extravasation in response to oxidative stress inducers PMA or soluble cigarette smoke extract. The pulmonary microvasculature and alveoli in the intact animal were imaged with comparable detail and fidelity to those in pump-perfused animals, opening the possibility for TPM of other thoracoabdominal organs under physiological and pathophysiological conditions.
Assuntos
Movimento Celular , Diagnóstico por Imagem , Endotélio Vascular/ultraestrutura , Coração/fisiologia , Pulmão/ultraestrutura , Fótons , Tórax/ultraestrutura , Animais , Carcinógenos/toxicidade , Adesão Celular , Células Cultivadas , Endotélio Vascular/citologia , Coração/efeitos dos fármacos , Leucócitos/efeitos dos fármacos , Leucócitos/metabolismo , Pulmão/citologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Perfusão , Alvéolos Pulmonares/citologia , Alvéolos Pulmonares/ultraestrutura , Ratos , Ratos Sprague-Dawley , Fumar/efeitos adversos , Acetato de Tetradecanoilforbol/toxicidade , Tórax/citologiaRESUMO
The treatment of severely burned patients has benefited from the grafting of skin substitutes obtained by expansion of epithelial cells in culture. The aim of this study was to evaluate whether the anatomic site chosen for harvesting skin had an impact on the quality of the derived cell cultures. Considering that hair follicles contain epithelial stem cells, we compared hairy skin sites featuring different densities and sizes of hair follicles for their capacity to generate high quality keratinocyte cultures. Three anatomic sites from adult subjects were compared: scalp, chest skin and p-auricular (comprising pre-auricular and post-auricular) skin. Keratin (K) 19 was used as a marker to evaluate the proportion of stem cells. Keratinocytes were isolated using the two-step thermolysin and trypsin cell extraction method, and cultured in vitro. The proportion of K19-positive cells harvested from p-auricular skin was about twice that of the scalp. This K19-positive cell content also remained higher during the first subcultures. In contrast to these in vitro results, the number of K19-positive cells estimated in situ on skin sections was about double in scalp as in p-auricular skin. Chest skin had the lowest number of K19-positive cells. These results indicate that in addition to the choice of an adult anatomic site featuring a high number of stem cells in situ, the quality of the cultures greatly depends on the ability to extract stem cells from the skin biopsy.
Assuntos
Células Epidérmicas , Queratinócitos/citologia , Transplante de Pele/métodos , Células-Tronco/citologia , Coleta de Tecidos e Órgãos/métodos , Adulto , Biomarcadores/análise , Células Cultivadas , Pavilhão Auricular/química , Pavilhão Auricular/citologia , Pavilhão Auricular/efeitos dos fármacos , Epiderme/química , Feminino , Humanos , Queratinas/análise , Masculino , Pessoa de Meia-Idade , Couro Cabeludo/química , Couro Cabeludo/citologia , Tórax/química , Tórax/citologia , Adulto JovemRESUMO
Legged locomotion requires that information local to one leg, and inter-segmental signals coming from the other legs are processed appropriately to establish a coordinated walking pattern.However, very little is known about the relative importance of local and inter-segmental signals when they converge upon the central pattern generators (CPGs) of different leg joints.We investigated this question on the CPG of the middle leg coxatrochanter (CTr)-joint of the stick insect which is responsible for lifting and lowering the leg.We used a semi-intact preparation with an intact front leg stepping on a treadmill, and simultaneously stimulated load sensors of the middle leg.We found that middle leg load signals induce bursts in the middle leg depressor motoneurons(MNs). The same local load signals could also elicit rhythmic activity in the CPG of the middle leg CTr-joint when the stimulation of middle leg load sensors coincided with front leg stepping. However, the influence of front leg stepping was generally weak such that front leg stepping alone was only rarely accompanied by switching between middle leg levator and depressor MN activity. We therefore conclude that the impact of the local sensory signals on the levatordepressor motor system is stronger than the inter-segmental influence through front leg stepping.
Assuntos
Geradores de Padrão Central/fisiologia , Extremidades/fisiologia , Locomoção/fisiologia , Desempenho Psicomotor/fisiologia , Potenciais de Ação/fisiologia , Animais , Teste de Esforço , Extremidades/inervação , Feminino , Lateralidade Funcional/fisiologia , Insetos , Periodicidade , Estimulação Física , Tórax/citologia , Tórax/fisiologiaAssuntos
Abdome/embriologia , Diferenciação Celular , Sistema Nervoso Central , Drosophila/citologia , Regulação da Expressão Gênica no Desenvolvimento , Neurônios/citologia , Abdome/fisiologia , Animais , Encéfalo/citologia , Encéfalo/embriologia , Sistema Nervoso Central/citologia , Sistema Nervoso Central/embriologia , Drosophila/embriologia , Células-Tronco/citologia , Tórax/citologia , Tórax/embriologiaRESUMO
The generation of distinct neuronal subtypes at different axial levels relies upon both anteroposterior and temporal cues. However, the integration between these cues is poorly understood. In the Drosophila central nervous system, the segmentally repeated neuroblast 5-6 generates a unique group of neurons, the Apterous (Ap) cluster, only in thoracic segments. Recent studies have identified elaborate genetic pathways acting to control the generation of these neurons. These insights, combined with novel markers, provide a unique opportunity for addressing how anteroposterior and temporal cues are integrated to generate segment-specific neuronal subtypes. We find that Pbx/Meis, Hox, and temporal genes act in three different ways. Posteriorly, Pbx/Meis and posterior Hox genes block lineage progression within an early temporal window, by triggering cell cycle exit. Because Ap neurons are generated late in the thoracic 5-6 lineage, this prevents generation of Ap cluster cells in the abdomen. Thoracically, Pbx/Meis and anterior Hox genes integrate with late temporal genes to specify Ap clusters, via activation of a specific feed-forward loop. In brain segments, "Ap cluster cells" are present but lack both proper Hox and temporal coding. Only by simultaneously altering Hox and temporal gene activity in all segments can Ap clusters be generated throughout the neuroaxis. This study provides the first detailed analysis, to our knowledge, of an identified neuroblast lineage along the entire neuroaxis, and confirms the concept that lineal homologs of truncal neuroblasts exist throughout the developing brain. We furthermore provide the first insight into how Hox/Pbx/Meis anteroposterior and temporal cues are integrated within a defined lineage, to specify unique neuronal identities only in thoracic segments. This study reveals a surprisingly restricted, yet multifaceted, function of both anteroposterior and temporal cues with respect to lineage control and cell fate specification.
Assuntos
Diferenciação Celular , Sistema Nervoso Central/citologia , Drosophila/citologia , Regulação da Expressão Gênica no Desenvolvimento , Neurônios/citologia , Células-Tronco/citologia , Abdome/fisiologia , Animais , Encéfalo/citologia , Drosophila/crescimento & desenvolvimento , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Neurônios/metabolismo , Células-Tronco/metabolismo , Tórax/citologiaRESUMO
The secondary neurons generated in the thoracic central nervous system of Drosophila arise from a hemisegmental set of 25 neuronal stem cells, the neuroblasts (NBs). Each NB undergoes repeated asymmetric divisions to produce a series of smaller ganglion mother cells (GMCs), which typically divide once to form two daughter neurons. We find that the two daughters of the GMC consistently have distinct fates. Using both loss-of-function and gain-of-function approaches, we examined the role of Notch signaling in establishing neuronal fates within all of the thoracic secondary lineages. In all cases, the 'A' (Notch(ON)) sibling assumes one fate and the 'B' (Notch(OFF)) sibling assumes another, and this relationship holds throughout the neurogenic period, resulting in two major neuronal classes: the A and B hemilineages. Apparent monotypic lineages typically result from the death of one sibling throughout the lineage, resulting in a single, surviving hemilineage. Projection neurons are predominantly from the B hemilineages, whereas local interneurons are typically from A hemilineages. Although sibling fate is dependent on Notch signaling, it is not necessarily dependent on numb, a gene classically involved in biasing Notch activation. When Numb was removed at the start of larval neurogenesis, both A and B hemilineages were still generated, but by the start of the third larval instar, the removal of Numb resulted in all neurons assuming the A fate. The need for Numb to direct Notch signaling correlated with a decrease in NB cell cycle time and may be a means for coping with multiple sibling pairs simultaneously undergoing fate decisions.