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Cell-to-cell Communication (cell-to-cell + communication)
Selected AbstractsCo-Cultures of Primary Cells on Self-Supporting Nanoporous Alumina Membranes,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Andreas Hoess Due to their unique properties, self-supporting nanoporous aluminum oxide (alumina) membranes are useful substrates for the indirect co-cultivation of cells. The membrane can act as a physical barrier between different cell types, whereas the cell-to-cell communication is guaranteed by the diffusion of soluble molecules or factors through the pores. With the help of such membranes the mRNA expression of hepatic genes can be induced in human adipose-derived mesenchymal stem cells (hASCs) during an indirect co-cultivation with primary mouse hepatocytes under different culture conditions. This proof of concept shows that such a cultivation approach is beneficial for different issues in the field tissue engineering or cell therapy. [source] The mouse VPAC2 receptor confers suprachiasmatic nuclei cellular rhythmicity and responsiveness to vasoactive intestinal polypeptide in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003David J. Cutler Abstract Expression of coherent and rhythmic circadian (, 24 h) variation of behaviour, metabolism and other physiological processes in mammals is governed by a dominant biological clock located in the hypothalamic suprachiasmatic nuclei (SCN). Photic entrainment of the SCN circadian clock is mediated, in part, by vasoactive intestinal polypeptide (VIP) acting through the VPAC2 receptor. Here we used mice lacking the VPAC2 receptor (Vipr2,/,) to examine the contribution of this receptor to the electrophysiological actions of VIP on SCN neurons, and to the generation of SCN electrical firing rate rhythms SCN in vitro. Compared with wild-type controls, fewer SCN cells from Vipr2,/, mice responded to VIP and the VPAC2 receptor-selective agonist Ro 25-1553. By contrast, similar proportions of Vipr2,/, and wild-type SCN cells responded to gastrin-releasing peptide, arginine vasopressin or N -methyl- d -aspartate. Moreover, VIP-evoked responses from control SCN neurons were attenuated by the selective VPAC2 receptor antagonist PG 99-465. In firing rate rhythm experiments, the midday peak in activity observed in control SCN cells was lost in Vipr2,/, mice. The loss of electrical activity rhythm in Vipr2,/, mice was mimicked in control SCN slices by chronic treatment with PG 99-465. These results demonstrate that the VPAC2 receptor is necessary for the major part of the electrophysiological actions of VIP on SCN cells in vitro, and is of fundamental importance for the rhythmic and coherent expression of circadian rhythms governed by the SCN clock. These findings suggest a novel role of VPAC2 receptor signalling, and of cell-to-cell communication in general, in the maintenance of core clock function in mammals, impacting on the cellular physiology of SCN neurons. [source] The regulation of the endosomal compartment by p53 the tumor suppressor geneFEBS JOURNAL, Issue 8 2009Xin Yu The endosomal compartment of the cell is involved in a number of functions including: (a) internalizing membrane proteins to multivesicular bodies and lysosomes; (b) producing vesicles that are secreted from the cell (exosomes); and (c) generating autophagic vesicles that, especially in times of nutrient deprivation, supply cytoplasmic components to the lysosome for degradation and recycling of nutrients. The p53 protein responds to various stress signals by initiating a transcriptional program that restores cellular homeostasis and prevents the accumulation of errors in a cell. As part of this process, p53 regulates the transcription of a set of genes encoding proteins that populate the endosomal compartment and impact upon each of these endosomal functions. Here, we demonstrate that p53 regulates transcription of the genes TSAP6 and CHMP4C, which enhance exosome production, and CAV1 and CHMP4C, which produce a more rapid endosomal clearance of the epidermal growth factor receptor from the plasma membrane. Each of these p53-regulated endosomal functions results in the slowing of cell growth and division, the utilization of catabolic resources and cell-to-cell communication by exosomes after a stress signal is detected by the p53 protein. These processes avoid errors during stress and restore homeostasis once the stress is resolved. [source] Vesicle traffic through intercellular bridges in DU 145 human prostate cancer cellsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2004Cristina Vidulescu Abstract We detected cell-to-cell communication via intercellular bridges in DU 145 human prostate cancer cells by fluorescence microscopy. Since DU 145 cells have deficient gap junctions, intercellular bridges may have a prominent role in the transfer of chemical signals between these cells. In culture, DU 145 cells are contiguous over several cell diameters through filopodial extensions, and directly communicate with adjacent cells across intercellular bridges. These structures range from 100 nm to 5 ,m in diameter, and from a few microns to at least 50,100 ,m in length. Time-lapse imagery revealed that (1) filopodia rapidly move at a rate of microns per minute to contact neighboring cells and (2) intercellular bridges are conduits for transport of membrane vesicles (1,3 ,m in diameter) between adjacent cells. Immunofluorescence detected alpha-tubulin in intercellular bridges and filopodia, indicative of microtubule bundles, greater than a micron in diameter. The functional meaning, interrelationship of these membrane extensions are discussed, along with the significance of these findings for other culture systems such as stem cells. Potential applications of this work include the development of anticancer therapies that target intercellular communication and controlling formation of cancer spheroids for drug testing. [source] Mechanisms Mediating Oestradiol Modulation of the Developing BrainJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2008M. M. McCarthy The brain has been known to be a sensitive target organ for the permanent organisational effects of gonadal steroids for close to 50 years. Recent advances have revealed a variety of unexpected cellular mechanisms by which steroids impact on the synaptic profile of hypothalamic nuclei critical to the control of reproduction. This review focuses on three in particular: 1) prostaglandins in the masculinisation of the preoptic area and control of male sexual behaviour; 2) GABA in the arcuate nucleus and potential control of the anterior pituitary; and 3) non-genomic activation of phosphotydolinositol 3 (PI3) kinase and glutamate in the ventromedial nucleus, which is relevant to the control of female reproductive behaviour. The importance of cell-to-cell communication, be it between neurones or between neurones and astrocytes, is highlighted as an essential principle for expanding the impact of steroids beyond those cells that express nuclear receptors. [source] Are yeasts free-living unicellular eukaryotes?LETTERS IN APPLIED MICROBIOLOGY, Issue 6 2005J.R. Dickinson Summary Yeasts are defined as unicellular fungi, yet many recent observations suggest their whole lifestyle is anything but unicellular. This review surveys the evidence that yeasts are really social organisms with cell-to-cell communication. [source] N -acyl-L-homoserine lactones: a class of bacterial quorum-sensing signals alter post-embryonic root development in Arabidopsis thalianaPLANT CELL & ENVIRONMENT, Issue 10 2008RANDY ORTÍZ-CASTRO ABSTRACT N -acyl-homoserine lactones (AHLs) belong to a class of bacterial quorum-sensing signals important for bacterial cell-to-cell communication. We evaluated Arabidopsis thaliana growth responses to a variety of AHLs ranging from 4 to 14 carbons in length, focusing on alterations in post-embryonic root development as a way to determine the biological activity of these signals. The compounds affected primary root growth, lateral root formation and root hair development, and in particular, N -decanoyl-HL (C10-HL) was found to be the most active AHL in altering root system architecture. Developmental changes elicited by C10-HL were related to altered expression of cell division and differentiation marker lines pPRZ1:uidA, CycB1:uidA and pAtEXP7:uidA in Arabidopsis roots. Although the effects of C10-HL were similar to those produced by auxins in modulating root system architecture, the primary and lateral root response to this compound was found to be independent of auxin signalling. Furthermore, we show that mutant and overexpressor lines for an Arabidopsis fatty acid amide hydrolase gene (AtFAAH) sustained altered growth response to C10-HL. All together, our results suggest that AHLs alter root development in Arabidopsis and that plants posses the enzymatic machinery to metabolize these compounds. [source] Connexin 26 and 30 Genes Mutations in Patients with Chronic Rhinosinusitis,THE LARYNGOSCOPE, Issue 2 2008FACS, Nicolas Y. BuSaba MD Abstract Objectives: Connexin proteins play an important role in cell-to-cell communication. Mutations in the genes that encode for these connexins may potentially lead to dysfunction in mucociliary clearance predisposing to chronic rhinosinusitis (CRS) or recurrent acute rhinosinusitis (RARS). The objective of this study was to assess for the presence of connexin 26 and 30 gene mutations in patients with CRS and RARS. Study Design: Prospective case series. Methods: Forty-six consecutive patients who were diagnosed with CRS or RARS at a single tertiary care facility were included in the study. Patients with known dysfunction in mucociliary clearance were excluded. The following clinical data were collected: age, gender, duration of disease and age at onset, personal history of otitis media and/or sensorineural hearing loss (SNHL), and family history of paranasal sinus disease and SNHL. Buccal swab deoxyribonucleic acid (DNA) specimens were sequenced for connexin 26 and 30 genes. Results: The study group consisted of 32 females and 14 males, 8 children and 38 adults. Adequate sequencing of connexin 30 gene was possible in all 46 specimens, but in only 19 specimens for connexin 26 gene. Connexin 30 gene mutations were not detected in any of the 46 specimens. Two of the 19 specimens had heterozygous mutations in the connexin 26 gene; there was one V371 mutation and one 35dG mutation. Both patients were adults; the patient with 35dG mutation had SNHL. Conclusion: Mutations in connexin 26 and 30 genes are rare in patients with CRS or RARS and do not seem to play a contributory role in the pathogensis of these disorders. [source] A novel communication role for CYP17A1 in the progression of castration-resistant prostate cancerTHE PROSTATE, Issue 9 2009Jennifer A. Locke Abstract BACKGROUND CYP17A1 is currently a target for total androgen blockade in advanced prostate cancer (CaP) patients. After castration, or removal of testicular androgens, CYP17A1 can act as a rate-limiting enzyme in androgen synthesis from cholesterol or other adrenal precursors within the tumor microenvironment ultimately contributing to disease progression. Herein we provide evidence that CYP17A1 could also be a mediator of cell-to-cell communication within the CaP tumor microenvironment. METHODS CYP17A1 expression was evaluated by immunohistochemical analysis of human tumor sections and Western blot analysis of CaP patients' serum and exosome isolates. CYP17A1 activity assays were conducted in human serum (and positive control human liver and kidney microsomes) using progesterone as a precursor and an LC-MS endpoint. RESULTS These studies revealed that the expression pattern of CYP17A1 is typical of a secretory protein as it is localized to the luminal pole of the cells in exocrine secretory mode. CYP17A1 is expressed in human serum and in fact is elevated in the serum of CaP patients as compared to healthy controls. Serum CYP17A1 activity could not be confirmed, however, verification of CYP17A1 expression in exosomes suggests a role in cell-to-cell communication within the tumor microenvironment. CONCLUSIONS CYP17A1 is a crucial enzyme for de novo androgen synthesis within the tumor microenvironment after removal of testicular androgens by castration. We provide evidence for a novel role for CYP17A1 in serum and further reiterate the importance of targeting this enzyme in CaP progression. Prostate 69: 928,937, 2009. © 2009 Wiley-Liss, Inc. [source] Heavy-ion-induced bystander killing of human lung cancer cells: Role of gap junctional intercellular communicationCANCER SCIENCE, Issue 4 2009Kosaku Harada The aim of the present study was to clarify the mechanisms of cell death induced by heavy-ion irradiation focusing on the bystander effect in human lung cancer A549 cells. In microbeam irradiation, each of 1, 5, and 25 cells under confluent cell conditions was irradiated with 1, 5, or 10 particles of carbon ions (220 MeV), and then the surviving fraction of the population was measured by a clonogenic assay in order to investigate the bystander effect of heavy-ions. In this experiment, the limited number of cells (0.0001,0.002%, 5,25 cells) under confluent cell conditions irradiated with 5 or 10 carbon ions resulted in an exaggerated 8,14% increase in cell death by clonogenic assay. However, these overshooting responses were not observed under exponentially growing cell conditions. Furthermore, these responses were inhibited in cells treated with an inhibitor of gap junctional intercellular communication (GJIC), whereas they were markedly enhanced by the addition of a stimulator of GJIC. The present results suggest that bystander cell killing by heavy-ions was induced mainly by direct cell-to-cell communication, such as GJIC, which might play important roles in bystander responses. (Cancer Sci 2009; 100: 684,688) [source] Morphological Evidence for Direct Interaction Between Gonadotrophin-Releasing Hormone Neurones and Astroglial Cells in the Human HypothalamusJOURNAL OF NEUROENDOCRINOLOGY, Issue 9 2007M. Baroncini In rodents, there is compelling evidence indicating that dynamic cell-to-cell communications involving cross talk between astroglial cells (such as astrocytes and specialised ependymoglial cells known as tanycytes) and neurones are important in regulating the secretion of gonadotrophin-releasing hormone (GnRH), the neurohormone that controls both sexual maturation and adult reproductive function. However, whether such astroglial cell,GnRH neurone interactions occur in the human brain is not known. In the present study, we used immunofluorescence to examine the anatomical relationship between GnRH neurones and glial cells within the hypothalamus of five women. Double-staining experiments demonstrated the ensheathment of GnRH neurone perikarya by glial fibrillary acidic protein (GFAP)-immunoreactive astrocyte processes in the periventricular zone of the tuberal region of the hypothalamus. GFAP immunoreactivity did not overlap that of GnRH at the GnRH neurone's projection site (i.e. the median eminence of the hypothalamus). Rather, human GnRH neuroendocrine fibres were found to be closely associated with vimentin or nestin-immunopositive radial gial processes likely belonging to tanycytes. In line with these light microscopy data, ultrastructural examination of GnRH-immunoreactive neurones showed numerous glial cells in direct apposition to pre-embedding-labelled GnRH cell bodies and/or dendrites in the infundibular nucleus, whereas postembedding immunogold-labelled GnRH nerve terminals were often seen to be enwrapped by glial cell processes in the median eminence. GnRH nerve button were sometimes visualised in close proximity to fenestrated pituitary portal blood capillaries and/or evaginations of the basal lamina that delineate the pericapillary space. In summary, these data demonstrate that GnRH neurones morphologically interact with astrocytes and tanycytes in the human brain and provide evidence that glial cells may contribute physiologically to the process by which the neuroendocrine brain controls the function of GnRH neurones in humans. [source] | |||||||||||||