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Optogenetic control of gut movements reveals peristaltic wave-mediated induction of cloacal contractions and reactivation of impaired gut motility. Front Physiol 2023; 14:1175951. [PMID: 37293264 PMCID: PMC10245550 DOI: 10.3389/fphys.2023.1175951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Gut peristalsis, recognized as a wave-like progression along the anterior-posterior gut axis, plays a pivotal role in the transportation, digestion, and absorption of ingested materials. The embryonic gut, which has not experienced ingested materials, undergoes peristalsis offering a powerful model for studying the intrinsic mechanisms underlying the gut motility. It has previously been shown in chicken embryos that acute contractions of the cloaca (an anus-like structure) located at the posterior end of the hindgut are tightly coupled with the arrival of hindgut-derived waves. To further scrutinize the interactions between hindgut and cloaca, we here developed an optogenetic method that produced artificial waves in the hindgut. A variant form of channelrhodopsin-2 (ChR2(D156C)), permitting extremely large photocurrents, was expressed in the muscle component of the hindgut of chicken embryos using Tol2-mediated gene transfer and in ovo electroporation techniques. The D156C-expressing hindgut responded efficiently to local pulses of blue light: local contractions emerge at an ectopic site in the hindgut, which were followed by peristaltic waves that reached to the endpoint of the hindgut. Markedly, the arrival of the optogenetically induced waves caused concomitant contractions of the cloaca, revealing that the hindgut-cloaca coordination is mediated by signals triggered by peristaltic waves. Moreover, a cloaca undergoing pharmacologically provoked aberrant contractions could respond to pulsed blue light irradiation. Together, the optogenetic technology developed in this study for inducing gut peristalsis paves the way to study the gut movement and also to explore therapeutic methodology for peristaltic disorders.
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Stiffness of primordial germ cells is required for their extravasation in avian embryos. iScience 2022; 25:105629. [DOI: 10.1016/j.isci.2022.105629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/14/2022] [Accepted: 11/16/2022] [Indexed: 11/21/2022] Open
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Distribution Map of Peristaltic Waves in the Chicken Embryonic Gut Reveals Importance of Enteric Nervous System and Inter-Region Cross Talks Along the Gut Axis. Front Cell Dev Biol 2022; 10:827079. [PMID: 35223851 PMCID: PMC8874353 DOI: 10.3389/fcell.2022.827079] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/17/2022] [Indexed: 01/15/2023] Open
Abstract
Gut peristaltic movements recognized as the wave-like propagation of a local contraction are crucial for effective transportation and digestion/absorption of ingested materials. Although the physiology of gut peristalsis has been well studied in adults, it remains largely unexplored how the cellular functions underlying these coordinated tissue movements are established along the rostral-caudal gut axis during development. The chicken embryonic gut serves as an excellent experimental model for elucidating the endogenous potential and regulation of these cells since peristalsis occurs even though no ingested material is present in the moving gut. By combining video-recordings and kymography, we provide a spatial map of peristaltic movements along the entire gut posterior to the duodenum: midgut (jejunum and ileum), hindgut, caecum, and cloaca. Since the majority of waves propagate bidirectionally at least until embryonic day 12 (E12), the sites of origin of peristaltic waves (OPWs) can unambiguously be detected in the kymograph. The spatial distribution map of OPWs has revealed that OPWs become progressively confined to specific regions/zones along the gut axis during development by E12. Ablating the enteric nervous system (ENS) or blocking its activity by tetrodotoxin perturb the distribution patterns of OPWs along the gut tract. These manipulations have also resulted in a failure of transportation of inter-luminally injected ink. Finally, we have discovered a functional coupling of the endpoint of hindgut with the cloaca. When surgically separated, the cloaca ceases its acute contractions that would normally occur concomitantly with the peristaltic rhythm of the hindgut. Our findings shed light on the intrinsic regulations of gut peristalsis, including unprecedented ENS contribution and inter-region cross talk along the gut axis.
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Cell Lineage, Self-Renewal, and Epithelial-to-Mesenchymal Transition during Secondary Neurulation. J Korean Neurosurg Soc 2021; 64:367-373. [PMID: 33906340 PMCID: PMC8128514 DOI: 10.3340/jkns.2021.0054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/03/2021] [Accepted: 04/07/2021] [Indexed: 11/27/2022] Open
Abstract
Secondary neurulation (SN) is a critical process to form the neural tube in the posterior region of the body including the tail. SN is distinct from the anteriorly occurring primary neurulation (PN); whereas the PN proceeds by folding an epithelial neural plate, SN precursors arise from a specified epiblast by epithelial-to-mesenchymal transition (EMT), and undergo self-renewal in the tail bud. They finally differentiate into the neural tube through mesenchymal-to-epithelial transition (MET). We here overview recent progresses in the studies of SN with a particular focus on the regulation of cell lineage, self-renewal, and EMT/MET. Cellular mechanisms underlying SN help to understand the functional diversity of the tail in vertebrates.
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Dermal Fibroblasts Internalize Phosphatidylserine-Exposed Secretory Melanosome Clusters and Apoptotic Melanocytes. Int J Mol Sci 2020; 21:ijms21165789. [PMID: 32806720 PMCID: PMC7461560 DOI: 10.3390/ijms21165789] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/06/2020] [Accepted: 08/09/2020] [Indexed: 12/27/2022] Open
Abstract
Pigmentation in the dermis is known to be caused by melanophages, defined as melanosome-laden macrophages. In this study, we show that dermal fibroblasts also have an ability to uptake melanosomes and apoptotic melanocytes. We have previously demonstrated that normal human melanocytes constantly secrete melanosome clusters from various sites of their dendrites. After adding secreted melanosome clusters collected from the culture medium of melanocytes, time-lapse imaging showed that fibroblasts actively attached to the secreted melanosome clusters and incorporated them. Annexin V staining revealed that phosphatidylserine (PtdSer), which is known as an 'eat-me' signal that triggers the internalization of apoptotic cells by macrophages, is exposed on the surface of secreted melanosome clusters. Dermal fibroblasts were able to uptake secreted melanosome clusters as did macrophages, and those fibroblasts express TIM4, a receptor for PtdSer-mediated endocytosis. Further, co-cultures of fibroblasts and melanocytes demonstrated that dermal fibroblasts internalize PtdSer-exposed apoptotic melanocytes. These results suggest that not only macrophages, but also dermal fibroblasts contribute to the collection of potentially toxic substances in the dermis, such as secreted melanosome clusters and apoptotic melanocytes, that have been occasionally observed to drop down into the dermis from the epidermis.
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Neural-fated self-renewing cells regulated by Sox2 during secondary neurulation in chicken tail bud. Dev Biol 2020; 461:160-171. [DOI: 10.1016/j.ydbio.2020.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 02/07/2020] [Indexed: 12/24/2022]
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Comparison of the 3-D patterns of the parasympathetic nervous system in the lung at late developmental stages between mouse and chicken. Dev Biol 2018; 444 Suppl 1:S325-S336. [PMID: 29792856 DOI: 10.1016/j.ydbio.2018.05.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/18/2018] [Accepted: 05/18/2018] [Indexed: 11/25/2022]
Abstract
Although the basic schema of the body plan is similar among different species of amniotes (mammals, birds, and reptiles), the lung is an exception. Here, anatomy and physiology are considerably different, particularly between mammals and birds. In mammals, inhaled and exhaled airs mix in the airways, whereas in birds the inspired air flows unidirectionally without mixing with the expired air. This bird-specific respiration system is enabled by the complex tubular structures called parabronchi where gas exchange takes place, and also by the bellow-like air sacs appended to the main part of the lung. That the lung is predominantly governed by the parasympathetic nervous system has been shown mostly by physiological studies in mammals. However, how the parasympathetic nervous system in the lung is established during late development has largely been unexplored both in mammals and birds. In this study, by combining immunocytochemistry, the tissue-clearing CUBIC method, and ink-injection to airways, we have visualized the 3-D distribution patterns of parasympathetic nerves and ganglia in the lung at late developmental stages of mice and chickens. These patterns were further compared between these species, and three prominent similarities emerged: (1) parasympathetic postganglionic fibers and ganglia are widely distributed in the lung covering the proximal and distal portions, (2) the gas exchange units, alveoli in mice and parabronchi in chickens, are devoid of parasympathetic nerves, (3) parasympathetic nerves are in close association with smooth muscle cells, particularly at the base of the gas exchange units. These observations suggest that despite gross differences in anatomy, the basic mechanisms underlying parasympathetic control of smooth muscles and gas exchange might be conserved between mammals and birds.
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Coordination between body growth and tissue growth: Wolffian duct elongation and somitogenesis proceed in harmony with axial growth. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2018; 62:79-84. [PMID: 29616742 DOI: 10.1387/ijdb.170290yt] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
During embryogenesis, different tissues develop coordinately, and this coordination is often in harmony with body growth. Recent studies allow us to understand how this harmonious regulation is achieved at the levels of inter-cellular, inter-tissue, and tissue-body relationships. Here, we present an overview of recently revealed mechanisms by which axial growth (tail growth) drives a variety of morphogenetic events, with a focus on the coordinated progression between Wolffian (nephric) duct elongation and somitogenesis. We also discuss how we can relate this coordination to the events occurring during limb bud outgrowth, since the limb buds and tail bud are appendage anlagen acquired during vertebrate evolution, both of which undergo massive elongation/outgrowth.
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Newly raised anti-VAChT and anti-ChAT antibodies detect cholinergic cells in chicken embryos. Dev Growth Differ 2017; 59:677-687. [DOI: 10.1111/dgd.12406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 01/02/2023]
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10
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Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by plasma membrane derived-vesicles. Mech Dev 2017. [DOI: 10.1016/j.mod.2017.04.232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Intercellular transfer of organelles during body pigmentation. Curr Opin Genet Dev 2017; 45:132-138. [PMID: 28605672 DOI: 10.1016/j.gde.2017.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/29/2017] [Accepted: 05/29/2017] [Indexed: 01/16/2023]
Abstract
The intercellular transfer of the melanin-producing organelle, called melanosome, from melanocytes to adjacent keratinocytes, is largely responsible for the coat colors and skin pigmentation of amniotes (birds, reptiles, and mammals). Although several hypotheses of melanin-transfer were proposed mainly by in vitro studies and electron microscopies, how the melanosome transfer takes place in the actual skin remained unclear. With advances in technologies of gene manipulations and high-resolution microscopy that allow direct visualization of plasma membrane, we are beginning to understand the amazing behaviors and dynamics of melanocytes. Studies in melanosome transfer further provide a clue to understand a general principle of intercellular organelle transport, including the intercellular translocations of mitochondria.
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In ovo gene manipulation of melanocytes and their adjacent keratinocytes during skin pigmentation of chicken embryos. Dev Growth Differ 2015; 57:232-41. [PMID: 25739909 DOI: 10.1111/dgd.12201] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 01/08/2015] [Accepted: 01/23/2015] [Indexed: 01/27/2023]
Abstract
During skin pigmentation in avians and mammalians, melanin is synthesized in the melanocytes, and subsequently transferred to adjacently located keratinocytes, leading to a wide coverage of the body surface by melanin-containing cells. The behavior of melanocytes is influenced by keratinocytes shown mostly by in vitro studies. However, it has poorly been investigated how such intercellular cross-talk is regulated in vivo because of a lack of suitable experimental models. Using chicken embryos, we developed a method that enables in vivo gene manipulations of melanocytes and keratinocytes, where these cells are separately labeled by different genes. Two types of gene transfer techniques were combined: one was a retrovirus-mediated gene infection into the skin/keratinocytes, and the other was the in ovo DNA electroporation into neural crest cells, the origin of melanocytes. Since the Replication-Competent Avian sarcoma-leukosis virus long terminal repeat with Splice acceptor (RCAS) infection was available only for the White leghorn strain showing little pigmentation, melanocytes prepared from the Hypeco nera (pigmented) were back-transplanted into embryos of White leghorn. Prior to the transplantation, enhanced green fluorescent protein (EGFP)(+) Neo(r+) -electroporated melanocytes from Hypeco nera were selectively grown in G418-supplemented medium. In the skin of recipient White leghorn embryos infected with RCAS-mOrange, mOrange(+) keratinocytes and transplanted EGFP(+) melanocytes were frequently juxtaposed each other. High-resolution confocal microscopy also revealed that transplanted melanocytes exhibited normal behaviors regarding distribution patterns of melanocytes, dendrite morphology, and melanosome transfer. The method described in this study will serve as a useful tool to understand the mechanisms underlying intercellular regulations during skin pigmentation in vivo.
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Low cost labeling with highlighter ink efficiently visualizes developing blood vessels in avian and mouse embryos. Dev Growth Differ 2013; 55:792-801. [DOI: 10.1111/dgd.12106] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 10/20/2013] [Accepted: 10/20/2013] [Indexed: 11/29/2022]
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Transgenesis of the Wolffian duct visualizes dynamic behavior of cells undergoing tubulogenesis in vivo. Dev Growth Differ 2013; 55:579-90. [PMID: 23550588 DOI: 10.1111/dgd.12047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 01/18/2013] [Accepted: 01/18/2013] [Indexed: 12/12/2022]
Abstract
Deciphering how the tubulogenesis is regulated is an essential but unsolved issue in developmental biology. Here, using Wolffian duct (WD) formation in chicken embryos, we have developed a novel method that enables gene manipulation during tubulogenesis in vivo. Exploiting that WD arises from a defined site located anteriorly in the embryo (pronephric region), we targeted this region with the enhanced green fluorescent protein (EGFP) gene by the in ovo electroporation technique. EGFP-positive signals were detected in a wide area of elongating WD, where transgenic cells formed an epithelial component in a mosaic manner. Time-lapse live imaging analyses further revealed dynamic behavior of cells during WD elongation: some cells possessed numerous filopodia, and others exhibited cellular tails that repeated elongation and retraction. The retraction of the tail was precisely regulated by Rho activity via actin dynamics. When electroporated with the C3 gene, encoding Rho inhibitor, WD cells failed to contract their tails, resulting in an aberrantly elongated process. We further combined with the Tol2 transposon-mediated gene transfer technique, and could trace EGFP-positive cells at later stages in the ureteric bud sprouting from WD. This is the first demonstration that exogenous gene(s) can directly be introduced into elongating tubular structures in living amniote embryos. This method has opened a way to investigate how a complex tubulogenesis proceeds in higher vertebrates.
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In vivo gene manipulations of epithelial cell sheets: a novel model to study epithelial-to-mesenchymal transition. Dev Growth Differ 2011; 53:378-88. [PMID: 21492151 DOI: 10.1111/j.1440-169x.2011.01252.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Embryonic cells are classified into two types of cells by their morphology, epithelial and mesenchymal cells. During dynamic morphogenesis in development, epithelial cells often switch to mesenchymal by the process known as epithelial-to-mesenchymal transition (EMT). EMT is a central issue in cancer metastasis where epithelial-derived tumor cells are converted to mesenchymal with high mobility. Although many molecules have been identified to be involved in the EMT mostly by in vitro studies, in vivo model systems have been limited. We here established a novel model with which EMT can be analyzed directly in the living body. By an electroporation technique, we targeted a portion of the lateral plate mesoderm that forms epithelial cell sheets delineating the kidney region, called nephric coelomic epithelium (Neph-CE). Enhanced green fluorescent protein-electroporated Neph-CE retained the epithelial integrity without invading into the underling stroma (mesonephros). The Neph-CE transgenesis further allowed us to explore EMT inducers in vivo, and to find that Ras-Raf and RhoA signals were potent inducers. Live-imaging confocal microscopy revealed that during EMT processes cells started extending cellular protrusions toward the stroma, followed by translocation of their cell bodies. Furthermore, we established a long-term tracing of EMT-induced cells, which were dynamically relocated within the kidney stroma. The Neph-CE-transgenesis will open a way to study cellular and molecular mechanisms underlying EMT directly in actual body.
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Genomically integrated transgenes are stably and conditionally expressed in neural crest cell-specific lineages. Dev Biol 2011; 353:382-95. [PMID: 21310145 DOI: 10.1016/j.ydbio.2011.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 01/08/2011] [Accepted: 02/01/2011] [Indexed: 10/18/2022]
Abstract
Neural crest cells (NCCs) are a transient embryonic structure that gives rise to a variety of cells including peripheral nervous system, melanocytes, and Schwann cells. To understand the molecular mechanisms underlying NCC development, a gene manipulation of NCCs by in ovo electroporation technique is a powerful tool, particularly in chicken embryos, the model animal that has long been used for the NCC research. However, since expression of introduced genes by the conventional electroporation method is transient, the mechanisms of late development of NCCs remain unexplored. We here report novel methods by which late-developing NCCs are successfully manipulated with electroporated genes. Introduced genes can be stably and/or conditionally expressed in a NCC-specific manner by combining 4 different techniques: Tol2 transposon-mediated genomic integration (Sato et al., 2007), a NCC-specific enhancer of the Sox10 gene (identified in this study), Cre/loxP system, and tet-on inducible expression (Watanabe et al., 2007). This is the first demonstration that late-developing NCCs in chickens are gene-manipulated specifically and conditionally. These methods have further allowed us to obtain ex vivo live-images of individual Schwann cells that are associated in axon bundles in peripheral tissues. Cellular activity and morphology dynamically change as development proceeds. This study has opened a new way to understand at the molecular and cellular levels how late NCCs develop in association with other tissues during embryogenesis.
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P03. Ex vivo live imaging at high resolution to directly visualize melanin transfer from melanocytes to keratinocytes. Differentiation 2010. [DOI: 10.1016/j.diff.2010.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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P10. Novel method to investigate the interactions between melanocytes and keratinocytes in developing skin. Differentiation 2010. [DOI: 10.1016/j.diff.2010.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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19
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P48. Formation of blood vessels is controlled by neural progenitor cells in the central nervous system. Differentiation 2010. [DOI: 10.1016/j.diff.2010.09.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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P02. Migration of human fibrosarcoma cells toward the blood vessel when transplanted into chicken embryo. Differentiation 2010. [DOI: 10.1016/j.diff.2010.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Ex vivo live-imaging at high resolution to directly visualize melanin transfer from melanocytes to keratinocytes. Dev Biol 2010. [DOI: 10.1016/j.ydbio.2010.05.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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22
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Tubular extension and cell epithelialization are coordinately regulated and influenced by adjacent tissues. Dev Biol 2010. [DOI: 10.1016/j.ydbio.2010.05.263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Notch signal is sufficient to direct an endothelial conversion from non-endothelial somitic cells conveyed to the aortic region by CXCR4. Dev Biol 2009; 335:33-42. [PMID: 19683521 DOI: 10.1016/j.ydbio.2009.08.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 08/08/2009] [Accepted: 08/10/2009] [Indexed: 11/26/2022]
Abstract
During the early formation of the dorsal aorta, the first-forming embryonic vessel in amniotes, a subset of somitic cells selected as presumptive angioblasts, migrates toward the dorsal aorta, where they eventually differentiate into endothelial cells. We have recently shown that these processes are controlled by Notch signals (Sato, Y., Watanabe, T., Saito, D., Takahashi, T., Yoshida, S., Kohyama, J., Ohata, E., Okano, H., and Takahashi, Y., 2008. Notch mediates the segmental specification of angioblasts in somites and their directed migration toward the dorsal aorta in avian embryos. Dev. Cell 14, 890-901.). Here, we studied a possible link between Notch and chemokine signals, SDF1/CXCR4, the latter found to be dominantly expressed in developing aorta/somites. Although CXCR4 overexpression caused a directed migration of somitic cells to the aortic region in a manner similar to Notch, no positive epistatic relationships between Notch and SDF1/CXCR4 were detected. After reaching the aortic region, the CXCR4-electroporated cells exhibited no endothelial character. Importantly, however, once provided with Notch activity, they could successfully be incorporated into developing vessels as endothelial cells. These findings were obtained combining the tetracycline-inducible gene expression method with the transposon-mediated stable gene transfer technique. We conclude that Notch activation is sufficient to direct naïve mesenchymal cells to differentiate into endothelial cells once the cells are conveyed to the aortic region.
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Abstract
The small GTPase Rac regulates neuronal behavior, but whether it also functions in neural progenitor cells has not yet been explored. Here we report that Rac contributes to the regulation of nuclear migration in neocortical progenitor cells. Rac1 is expressed by progenitor cells in a unique spatiotemporal pattern. Cross-sectional immunohistochemical examination revealed intense Rac1 immunoreactivity at the ventricular surface. Similar staining patterns were obtained by immunofluorescence for a Rac-activator, Tiam1, and by reactions to detect the GTP-bound (active) form of Rac. En face inspection of the ventricular surface revealed that apical Rac1 localization was most frequent in M-phase cells, and the endfeet of cells in other cell cycle phases also showed apical Rac1 distribution at lower frequencies. To ask whether progenitor cell behavior prior to and during M phase is Rac-dependent, we monitored individual DiI-labeled progenitor cells live in the presence of a Rac inhibitor, NSC23766. We observed significantly retarded adventricular nuclear migration, as well as cytokinesis failures. Similar inhibitory effects were obtained by forced expression of a dominant-negative Rac1. These results suggest that Rac may play a role in interkinetic nuclear migration in the developing mouse brain.
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Early segregation of germ and somatic lineages during gonadal regeneration in the annelid Enchytraeus japonensis. Curr Biol 2006; 16:1012-7. [PMID: 16713959 DOI: 10.1016/j.cub.2006.04.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Revised: 03/13/2006] [Accepted: 03/30/2006] [Indexed: 11/17/2022]
Abstract
Although regeneration studies are useful for understanding how organs renew, little information is available about regeneration of reproductive organs and germ cells. We here describe the behavior of germ-cell precursors during regeneration of the oligochaete annelid worm Enchytraeus japonensis, which has the remarkable feature of undergoing asexual (by fission) and sexual reproduction . We first found that the gonad can regenerate from any body fragment yielded by fission during asexual reproduction. We then examined behavior of germ-cell lineage during this regenerative process, by using a homolog of the Piwi gene (Ej-piwi) as a marker. We found that in asexually growing animals, specialized cells expressing Ej-piwi are distributed widely in the body as single cells. These cells seem to serve as a reservoir of germ-cell precursors because during asexual propagation these cells migrate into the regenerating tissue, where they ultimately settle in the prospective gonads, and give rise to germ cells upon sexualization. These cells are distinct from the neoblasts, thought to be stem cells in other animals. This is the first report to directly show that the germ and somatic lineages are segregated in asexually growing animals and behave differently during regeneration.
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Abstract
OBJECTIVE Previous reports of the postprandial regulation of leptin are controversial, and there have been few studies on the effects of breast-feeding on postprandial regulation in newborn infants. We examined the response of plasma leptin to breast- and formula-feeding in newborn infants. METHODS We measured the plasma leptin levels using an enzyme-linked immunosorbent assay kit before and after feeding in 12 breast-fed and 11 formula-fed mature infants. RESULTS There was no significant difference in plasma leptin levels in breast-fed infants before and after feeding or in artificially fed infants before and after feeding. CONCLUSION Our results suggest that feeding does not play a role in the acute response of circulating leptin levels in either breast- or formula-fed infants.
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Postnatal and postprandial changes in plasma concentrations of glicentin in term and preterm infants. Acta Paediatr 2003; 92:1175-9. [PMID: 14632334 DOI: 10.1080/08035250310000514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
AIM To examined the changes in basal plasma concentrations of glicentin in developing children and the postnatal and postprandial changes in plasma glicentin levels in infants. METHODS Glicentin, an active component of enteroglucagon, is considered to have a significant trophic action on the intestinal mucosa. Fasting plasma concentrations of glicentin in healthy children and in term and preterm infants were measured before and 30 min after feeding during the first 14 d of life. RESULTS Plasma basal concentrations of glicentin in children under 1 y of age were significantly higher than those in children aged 1 to 15 y. Plasma basal concentrations of glicentin at 5 or 6 d (2496 and 2190 pg/ml) and at 14 d (2987 and 2817 pg/ml) after birth were significantly higher than those at 1 or 2 d (1098 and 1240 pg/ml) after birth in normal birthweight (NBW) and low-birthweight (LBW) infants. There was no significant difference in the glicentin level between infants at 1 or 2 d (1864 pg/ml) and at 5 or 6 d (1910 pg/ml) after birth in very-low birthweight (VLBW) infants, but the levels at 14 d (3310 pg/ml) after birth were significantly higher than either of those levels. Plasma glicentin concentrations after feeding were significantly higher than those before feeding at 1 or 2 d and at 5 or 6 d after birth in NBW and LBW infants, but a significant increase in the plasma glicentin level after feeding was first observed at 14 d after birth in VLBW infants. There were no significant differences in the basal plasma (2401 and 2718 pg/ml) and postprandial (3007 and 3912 pg/ml) glicentin levels between breastfed and formula-fed infants. CONCLUSION The results of the study suggest that glicentin may play an important role in intestinal mucosal growth in the early period of life, although its role in VLBW infants should be further investigated.
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Clinical significance of the serum surfactant protein D and KL-6 levels in patients with measles complicated by interstitial pneumonia. Eur J Pediatr 2001; 160:425-9. [PMID: 11475580 DOI: 10.1007/s004310100763] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UNLABELLED To examine the value of surfactant protein D and KL-6 as markers for the diagnosis and the severity of interstitial pneumonia caused by measles infection, surfactant protein D, KL-6 and lactic acid dehydrogenase were measured serially in three patients with measles complicated by interstitial pneumonia as compared to ten measles infected patients without interstitial pneumonia. The serum surfactant protein D and KL-6 levels were higher in patients with measles and interstitial pneumonia as compared to those with measles without interstitial pneumonia. In patients with measles and interstitial pneumonia, the respiratory distress and the alveolar-arterial oxygen differences improved after steroid pulse therapy while the serum surfactant protein D level decreased dramatically under the cut-off level and earlier than the KL-6 level. On the contrary, the serum KL-6 level increased transiently and it took longer to decrease below the cut-off level as compared to the pattern observed for serum surfactant protein D. The serum lactic acid dehydrogenase level changes were between those of the surfactant protein D and KL-6 levels. CONCLUSION Surfactant protein D and KL-6 are easily measured and useful markers for the diagnosis of interstitial pneumonia caused by measles infection. Early decrease of surfactant protein D contrasts with the transient increase of KL-6 levels after prednisolone pulse therapy.
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Sources of plasma leptin in infants after feeding. Acta Paediatr 2000; 89:745-6. [PMID: 10914978 DOI: 10.1080/080352500750044151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Abstract
The wing of Drosophila is separated into several sectors by the wing veins. Vein primordia are specified by the positional information provided by hedgehog and decapentaplegic in the wing imaginal disc and express the key regulatory gene rhomboid. One model of this process is that boundaries of gene expression regulated by hedgehog or decapentaplegic provide reference points where rhomboid transcription is activated. We present an analysis of the gene plexus, whose loss of function causes an excess vein phenotype. Molecular cloning revealed that plexus encodes a novel 1990-amino acid protein with cysteine-rich motifs. Plexus protein was ubiquitously expressed and was tightly associated with the nuclear matrix. In plexus mutant wing imaginal discs, an anteroposterior positional coordinate was established normally as revealed by the wild-type pattern of spalt major and knirps expression. However, the expression of several vein-specific and intervein-specific genes was misregulated, as if they had neglected the positional coordinate. These results suggest that Plexus is an essential component of a global repressor of vein differentiation. Although Plexus protein was expressed in vein primordia of the wing disc, it does not appear to interfere with vein differentiation in the normal position. A genetic epistasis test between px and knirps suggests that plexus acts downstream of knirps. We propose that the vein differentiation takes place by inactivation of the plexus-mediated repression by prepattern genes such as knirps. Plexus may regulate transcription of vein-and intervein-specific genes by tethering transcriptional regulators to specific locations in the nucleus.
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Decreased bone mineral density during GnRH analog therapy and polymorphism of estrogen receptor gene in precocious puberty. Endocr J 1999; 46 Suppl:S55-7. [PMID: 12054121 DOI: 10.1507/endocrj.46.suppl_s55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Acute lymphoblastic leukemia accompanied by severe hypercalcemia: successful treatment including aminohydroxypropylidene bisphosphonate (pamidronate disodium). Pediatr Hematol Oncol 1998; 15:283-6. [PMID: 9615329 DOI: 10.3109/08880019809028798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
A report is presented of a girl with Graves' disease, which was diagnosed at the age of 1.7 years. The mother had no thyroid disease. The patient developed signs of hyperthyroidism shortly before her first birthday, and the most prominent manifestations were accelerated skeletal maturation and linear growth, and dilatation of the brain ventricles. The latter manifestation, which has not been reported previously, was reversible upon normalisation of thyroid function with antithyroid treatment for three years.
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