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Specialized Cells (specialized + cell)
Selected AbstractsThe mouse sperm proteome characterized via IPG strip prefractionation and LC-MS/MS identificationPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2008Mark A. Baker Dr. Abstract Proteomic profiling of the mouse spermatozoon has generated a unique and valuable inventory of candidates that can be mined for potential contraceptive targets and to further our understanding of the PTMs that regulate the functionality of this highly specialized cell. Here we report the identification of 858 proteins derived from mouse spermatozoa, 23 of which demonstrated testis only expression. The list contained many proteins that are known constituents of murine spermatozoa including Izumo, Spaca 1, 3, and 5, Spam 1, Zonadhesin, Spesp1, Smcp, Spata 6, 18, and 19, Zp3r, Zpbp 1 and 2, Spa17, Spag 6, 16, and 17, CatSper4, Acr, Cylc2, Odf1 and 2, Acrbp, and Acrv1. Certain protein families were highly represented in the proteome. For example, of the 42 gene products classified as proteases, 26 belonged to the 26S-proteasome. Of the many chaperones identified in this proteome, eight proteins with a TCP-1 domain were found, as were seven Rab guanosine triphosphatases. Finally, our list yielded three putative seven-transmembrane proteins, two of which have no known tissue distribution, an extragenomic progesterone receptor and three unique testis-specific kinases all of which may have some potential in the future regulation of male fertility. [source] Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left,right asymmetry in the mouseDEVELOPMENTAL DYNAMICS, Issue 12 2008Jeffrey D. Lee Abstract Establishment of left,right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left,right asymmetry. Developmental Dynamics 237:3464,3476, 2008. © 2008 Wiley-Liss, Inc. [source] Id2, Id3, and Id4 proteins show dynamic changes in expression during vibrissae follicle developmentDEVELOPMENTAL DYNAMICS, Issue 6 2008Nigel L. Hammond Abstract Id proteins are involved in the transcriptional control of many fundamental biological processes, including differentiation and lineage commitment. We studied Id2, Id3, and Id4 protein expression during different stages of rat vibrissa follicle development using immunohistochemistry. Id2 was highly expressed in the cytoplasm of specialized cells in the basal epidermis and outer root sheath during early stages of follicle development. These cells were identified as Merkel cells (MCs) by means of double-immunolabeling with synaptophysin and cytokeratin-20, and persisted in neonatal follicles. Id3 immunofluorescence was characterized by membrane-associated expression in basal epithelial cells of follicles early in development. Subsequently follicle epithelial cells switched to have strong nuclear labeling, also a feature of newly forming dermal papilla cells. Id4 expression was primarily associated with innervation of the developing follicle musculature. These observations illustrate dynamic expression patterns of Id2 and Id3 proteins in developing follicles and specifically link Id2 expression to Merkel cell specification. Developmental Dynamics 237:1653,1661, 2008. © 2008 Wiley-Liss, Inc. [source] Immunolocalization of BK channels in hippocampal pyramidal neuronsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2006Claudia A. Sailer Abstract Neurons are highly specialized cells in which the integration and processing of electrical signals critically depends on the precise localization of ion channels. For large-conductance Ca2+ - activated K+ (BK) channels, targeting to presynaptic membranes in hippocampal pyramidal cells was reported; however, functional evidence also suggests a somatodendritic localization. Therefore we re-examined the subcellular distribution of BK channels in mouse hippocampus using a panel of independent antibodies in a combined approach of conventional immunocytochemistry on cultured neurons, pre- and postembedding electron microscopy and immunoprecipitation. In cultured murine hippocampal neurons, the colocalization of BK channels with both pre- and postsynaptic marker proteins was observed. Electron microscopy confirmed targeting of BK channels to axonal as well as dendritic membranes of glutamatergic synapses in hippocampus. A postsynaptic localization of BK channels was also supported by the finding that the channel coimmunoprecipitated with PSD95, a protein solely expressed in the postsynaptic compartment. These results thus demonstrate that BK channels reside in both post- and presynaptic compartments of hippocampal pyramidal neurons. [source] ON THE EVOLUTION OF DIFFERENTIATED MULTICELLULARITYEVOLUTION, Issue 2 2009Martin Willensdorfer Most conspicuous organisms are multicellular and most multicellular organisms develop somatic cells to perform specific, nonreproductive tasks. The ubiquity of this division of labor suggests that it is highly advantageous. In this article I present a model to study the evolution of specialized cells. The model allows for unicellular and multicellular organisms that may contain somatic (terminally differentiated) cells. Cells contribute additively to a quantitative trait. The fitness of the organism depends on this quantitative trait (via a benefit function), the size of the organism, and the number of somatic cells. The model allows one to determine when somatic cells are advantageous and to calculate the optimum number (or fraction) of reproductive cells. I show that the fraction of reproductive cells is always surprisingly high. If somatic cells are very small, they can outnumber reproductive cells but their biomass is still less than the biomass of reproductive cells. I discuss the biology of primitive multicellular organisms with respect to the model predictions. I find a good agreement and outline how this work can be used to guide further quantitative studies of multicellularity. [source] Choanoflagellates, choanocytes, and animal multicellularityINVERTEBRATE BIOLOGY, Issue 1 2004Manuel Maldonado Abstract. It is widely accepted that multicellular animals (metazoans) constitute a monophyletic unit, deriving from ancestral choanoflagellate-like protists that gave rise to simple choanocyte-bearing metazoans. However, a re-assessment of molecular and histological evidence on choanoflagellates, sponge choanocytes, and other metazoan cells reveals that the status of choanocytes as a fundamental cell type in metazoan evolution is unrealistic. Rather, choanocytes are specialized cells that develop from non-collared ciliated cells during sponge embryogenesis. Although choanocytes of adult sponges have no obvious homologue among metazoans, larval cells transdifferentiating into choanocytes at metamorphosis do have such homologues. The evidence reviewed here also indicates that sponge larvae are architecturally closer than adult sponges to the remaining metazoans. This may mean that the basic multicellular organismal architecture from which diploblasts evolved, that is, the putative planktonic archimetazoan, was more similar to a modern poriferan larva lacking choanocytes than to an adult sponge. Alternatively, it may mean that other metazoans evolved from a neotenous larva of ancient sponges. Indeed, the Porifera possess some features of intriguing evolutionary significance: (1) widespread occurrence of internal fertilization and a notable diversity of gastrulation modes, (2) dispersal through architecturally complex lecithotrophic larvae, in which an ephemeral archenteron (in dispherula larvae) and multiciliated and syncytial cells (in trichimella larvae) occur, (3) acquisition of direct development by some groups, and (4) replacement of choanocyte-based filter-feeding by carnivory in some sponges. Together, these features strongly suggest that the Porifera may have a longer and more complicated evolutionary history than traditionally assumed, and also that the simple anatomy of modern adult sponges may have resulted from a secondary simplification. This makes the idea of a neotenous evolution less likely than that of a larva-like choanocyte-lacking archimetazoan. From this perspective, the view that choanoflagellates may be simplified sponge-derived metazoans, rather than protists, emerges as a viable alternative hypothesis. This idea neither conflicts with the available evidence nor can be disproved by it, and must be specifically re-examined by further approaches combining morphological and molecular information. Interestingly, several microbial lin°Cages lacking choanocyte-like morphology, such as Corallochytrea, Cristidiscoidea, Ministeriida, and Mesomycetozoea, have recently been placed at the boundary between fungi and animals, becoming a promising source of information in addition to the choanoflagellates in the search for the unicellular origin of animal multicellularity. [source] Syntaxin 16: Unraveling cellular physiology through a ubiquitous SNARE moleculeJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2010Yanan Chen Syntaxin 16 (Syx16) is member of the soluble N -ethylmaleimide sensitive factor attachment protein receptor (SNARE) family of molecules that functions in membrane fusion in eukaryotic cells. A rather ubiquitously expressed, tail-anchored membrane protein localized mainly at the trans-Golgi network (TGN), it mediates primarily retrograde endosomal-TGN transport. In spite of its ubiquitous expression, Syx16 has specific and interesting roles in the physiology of specialized cells, including Glut4 dynamics, dendritic outgrowth-related membrane traffic, and cytokinesis. We discussed these physiological functions of Syx16 in the light of what is known of its subcellular localization, vesicular trafficking pathways involved, cognate SNARE partners and other interacting proteins. Further, we speculate on some possible pathophysiological roles of Syx16. J. Cell. Physiol. 225: 326,332, 2010. © 2010 Wiley-Liss, Inc. [source] Human embryonic stem cells and liver diseases: From basic research to future clinical applicationJOURNAL OF DIGESTIVE DISEASES, Issue 1 2008Zheng WANG Human embryonic stem cells (hESC) provide access to the earliest stages of human development and because of their high proliferation capability, pluripotency and low immunogenicity may serve as a potential source of specialized cells for regenerative medicine. hESC-derived hepatocyte-like cells exhibit characteristic hepatocyte morphology, express hepatocyte markers and are capable of executing a range of hepatocyte functions. However, there are many challenges and obstacles to be overcome before the use of hESC and hESC-derived hepatocyte-like cells in clinical practice can be realized. Here, we highlight some of the recent efforts in this area, in hope of providing insights toward this complex yet important area of therapeutical modality for treating patients with liver disease. [source] Poster Sessions CP10: Blood,Brain BarrierJOURNAL OF NEUROCHEMISTRY, Issue 2002M. A. García Kinetic analysis of vitamin C uptake has demonstrated that specialized cells take up ascorbic acid (AA), the reduced form of vitamin C, through sodium-AA cotransporters. Recently, two different isoforms of sodium-vitamin C cotransporters (SVCT 1, 2) that mediate high affinity Na+ -dependent l -ascorbic acid have been cloned. SVCT2 was detected mainly in choroid plexus cells and neurons, however, there are no evidences of SVCT2 expression in glial cells. High concentrations of vitamin C has been demonstrated in brain hypothalamic area. The hypothalamic glial cells, known as alpha and beta tanycytes, are specialized ependymal cells that bridge the cerebrospinal fluid and the portal blood of the median eminence. Our hypothesis postulates that tanycytes take up reduced vitamin C from the portal blood and cerebrospinal fluid generating an high concentration of this vitamin in brain hypothalamic area. In situ immunohistochemical analyses demonstrated that SVCT2 transporter is selectively expressed in apical region of tanycytes. A newly developed primary culture of mouse hypothalamic tanycytes was used to confirm the expression and function of SVCT2 isoform in these cells. Reduced vitamin C uptake was temperature and sodium dependent. Kinetic analysis showed an apparent Km of 20 ,m and a Vmax of 45 pmol/min per million cells for the transport of ascorbic acid. The expression of SVCT2 was confirmed by immunoblots and RT,PCR. Tanycytes may perform a neuroprotective role concentrating the vitamin C in the hypothalamic area. Acknowledgements:, Supported by Grands FONDECYT 1010843 and DIUC-GIA 201.034.006-1.4 from Concepción University. [source] Mesenchymal cells in the liver , one cell type or two?LIVER INTERNATIONAL, Issue 4 2002G. Ramadori Abstract: The wall of the liver sinusoid is made of highly specialized cells, the hepatic stellate cells (HSC) which together with the sinusoidal endothelial cells represent a loose barrier to the corpusculate part of the blood flowing through the liver. Quiescent stellate cells (quiescent HSC) store Vitamin A; "activated" stellate cells become involved in the reaction to acute or chronic noxae damaging the liver parenchyma. Activated HSC show increased protein synthesis capacity, increased DNA-synthesis and acquire a myofibroblast-like phenotype. Under similar conditions liver myofibroblasts (MF) of the portal field and of the pericentral area may also become "activated" by increasing protein synthesis, DNA synthesis and cell division. They express the fibulin-2 gene and produce large amounts of IL-6. In contrast to "activated" HSC they do not undergo spontaneous apoptosis in vitro and do not express the CD95-ligand gene. So far no definite prove has been found for a "transdifferentiation" of HSC to myofibroblasts. On the contrary an increasing amount of data support the conviction that HSC and MF represent two similar but not identical cell populations the latter being comparable to those of other organs. [source] Prostatic stromal cells derived from benign prostatic hyperplasia specimens possess stem cell like propertyTHE PROSTATE, Issue 12 2007Victor K. Lin Abstract INTRODUCTION The hyper-proliferative activity of stromal smooth muscle (SM) cells is believed to be responsible for the pathogenesis of benign prostatic hyperplasia (BPH). We have observed that those stromal cells can differentiate into unrelated specialized cells. We thus hypothesize that stromal cells derived from adults prostate specimens may contain adult stem cells. To test this hypothesis, human prostate stromal primary cultures were established and used for characterization of their stem cell properties. METHODS Immunoblotting, immunohistochemistry, RT-PCR, and tissue culture techniques were used to characterize the primary cultured human prostate-derived stromal cells for their stem cell and differentiation properties. The plasticity of these stromal cells was analyzed using cell culture and histology techniques. RESULTS Primary cultured prostate stromal cells from BPH patient possess polygonal and elongated fibroblast/myofibroblast cellular morphology. They are positive in CD30, CD34, CD44, NSE, CD133, Flt-1, stem cell factor (SCF), and neuron-specific enolase (NSE), but negative in C-Kit, stem cell antigen (SCA), SH2, CD11b. Expression of SM myogenic markers in these cells may be induced by sodium butyrate (NaBu) treatment. Induction to osteogenic and adipogenic differentiation in these cells is also evident. CONCLUSIONS Our study on primary stromal cells from BPH patients have yielded many interesting findings that these prostate stroma cells possess: (1) mesenchymal stem cell (MSC) markers; (2) strong proliferative potential; and (3) ability to differentiate or transdifferentiate to myogenic, adipogenic, and osteogenic lineages. These cell preparations may serve as a potential tool for studies in prostate adult stem cell research and the regulation of benign prostatic hyperplasia. Prostate 67: 1265,1276, 2007. © 2007 Wiley-Liss, Inc. [source] Osteoclast-targeting small molecules for the treatment of neoplastic bone metastasesCANCER SCIENCE, Issue 11 2009Makoto Kawatani Osteoclasts are highly specialized cells that resorb bone, and their abnormal activity is implicated in a variety of human bone diseases. In neoplastic bone metastasis, the bone destruction caused by osteoclasts is not only associated with the formation and progression of metastatic lesions, but also could contribute to frequent complications such as severe pain and pathological fractures, which greatly diminish the quality of life of patients. Bisphosphonates, potent antiresorptive drugs, have been shown to have efficacy for treating bone metastases in many types of cancer, and the development of various molecularly targeted agents is currently proceeding. Thus, inhibition of osteoclast function is now established as an important treatment strategy for bony metastases. This review focuses on promising small molecules that disrupt osteoclast function and introduces our chemical/biological approach for identifying osteoclast-targeting small molecular inhibitors. (Cancer Sci 2009) [source] Control of mucosal polymicrobial populations by innate immunityCELLULAR MICROBIOLOGY, Issue 9 2009Katie L. Mason Summary The gastrointestinal tract carries out the complex process of localizing the polymicrobial populations of the indigenous microbiota to the lumenal side of the GI mucosa while absorbing nutrients from the lumen and preventing damage to the mucosa. This process is accomplished through a combination of physical, innate and adaptive host defences and a ,strategic alliance' with members of the microbiota. To cope with the constant exposure to a diverse microbial community, the GI tract, through the actions of a number of specialized cells in the epithelium and lamina propria, has layers of humoral, physical and cellular defences that limit attachment, invasion and dissemination of the indigenous microbiota. However, the role of the microbiota in this dynamic balance is vital and serves as another level of ,innate' defence. We are just beginning to understand how bacterial metabolites aid in the control of potential pathogens within the microbiota and limit inflammatory responses to the microbiota, concepts that will impact our understanding of the biological effects of antibiotics, diet and probiotics on mucosal inflammatory responses. [source] | |||||||||||||