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Cell Communication (cell + communication)
Selected AbstractsREVIEW ARTICLE: The Role of Placental Exosomes in ReproductionAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010Lucia Mincheva-Nilsson Citation Mincheva-Nilsson L, Baranov V. The Role of Placental Exosomes in Reproduction. Am J Reprod Immunol 2010 Cell communication comprises cell,cell contact, soluble mediators and intercellular nanotubes. There is, however, another cell,cell communication by released membrane-bound microvesicles that convey cell,cell contact ,by proxy' transporting signals/packages of information from donor to recipient cells locally and/or at a distance. The nanosized exosomes comprise a specialized type of microvesicles generated within multivesicular bodies (MVB) and released upon MVB fusion with the plasma membrane. Exosomes are produced by a variety of immune, epithelial and tumor cells. Upon contact, exosomes transfer molecules that can render new properties and/or reprogram their recipient cells. Recently, it was discovered that the syncytiotrophoblast constitutively and throughout the pregnancy secretes exosomes. The placenta-derived exosomes are immunosuppressive and carry proteins and RNA molecules that in a redundant way influence a number of mechanisms and promote the fetal allograft survival. In this review, we summarize the current knowledge on the nature of placenta-derived exosomes and discuss their role in pregnancy. [source] Autoinducers extracted from microbial mats reveal a surprising diversity of N -acylhomoserine lactones (AHLs) and abundance changes that may relate to diel pHENVIRONMENTAL MICROBIOLOGY, Issue 2 2009Alan W. Decho Summary Microbial mats are highly structured and diverse communities, and one of the earliest-known life assemblages. Mat bacteria interact within an environment marked by strong geochemical gradients and fluctuations. We examined natural mat systems for the presence of autoinducers involved in quorum sensing, a form of cell,cell communication. Our results revealed that a diverse array of N -acylhomoserine lactones (AHLs) including C4 - to C14 -AHLs, were identified from mat extracts using mass spectrometry (MS), with further confirmation by MS/MS-collision-induced dissociation (CID), and additions of external standards. Microelectrode measurements showed that mats exhibited diel pH fluctuations, ranging from alkaline (pH 9.4) during daytime (net photosynthesis) to acidic (pH 6.8) during darkness (net respiration/fermentation). Under laboratory conditions, AHLs having shorter acyl-chains were degraded within the time frame that daily alkaline pH (> 8.2) conditions exist in mats. Intensive sampling of mats after full day- or night-time incubations revealed that accumulations of extractable shorter-chain AHLs (e.g. C8 - and C10 -AHLs) were significantly (P < 0.001) diminished during daytime. Our study offers evidence that stabilities of AHLs under natural conditions may be influenced by the proximal extracellular environment. We further propose that the ancient periodicity of photosynthesis/respiration in mats may potentially drive a mechanism for diel differences in activities of certain autoinducers, and hence bacterial activities mediated through quorum sensing. [source] Visualization of local Ca2+ dynamics with genetically encoded bioluminescent reportersEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2005Kelly L. Rogers Abstract Measurements of local Ca2+ signalling at different developmental stages and/or in specific cell types is important for understanding aspects of brain functioning. The use of light excitation in fluorescence imaging can cause phototoxicity, photobleaching and auto-fluorescence. In contrast, bioluminescence does not require the input of radiative energy and can therefore be measured over long periods, with very high temporal resolution. Aequorin is a genetically encoded Ca2+ -sensitive bioluminescent protein, however, its low quantum yield prevents dynamic measurements of Ca2+ responses in single cells. To overcome this limitation, we recently reported the bi-functional Ca2+ reporter gene, GFP-aequorin (GA), which was developed specifically to improve the light output and stability of aequorin chimeras [V. Baubet, et al., (2000) PNAS, 97, 7260,7265]. In the current study, we have genetically targeted GA to different microdomains important in synaptic transmission, including to the mitochondrial matrix, endoplasmic reticulum, synaptic vesicles and to the postsynaptic density. We demonstrate that these reporters enable ,real-time' measurements of subcellular Ca2+ changes in single mammalian neurons using bioluminescence. The high signal-to-noise ratio of these reporters is also important in that it affords the visualization of Ca2+ dynamics in cell,cell communication in neuronal cultures and tissue slices. Further, we demonstrate the utility of this approach in ex-vivo preparations of mammalian retina, a paradigm in which external light input should be controlled. This represents a novel molecular imaging approach for non-invasive monitoring of local Ca2+ dynamics and cellular communication in tissue or whole animal studies. [source] A study on genomic distribution and sequence features of human long inverted repeats reveals species-specific intronic inverted repeatsFEBS JOURNAL, Issue 7 2009Yong Wang The inverted repeats present in a genome play dual roles. They can induce genomic instability and, on the other hand, regulate gene expression. In the present study, we report the distribution and sequence features of recombinogenic long inverted repeats (LIRs) that are capable of forming stable stem-loops or palindromes within the human genome. A total of 2551 LIRs were identified, and 37% of them were located in long introns (largely > 10 kb) of genes. Their distribution appears to be random in introns and is not restrictive, even for regions near intron,exon boundaries. Almost half of them comprise TG/CA-rich repeats, inversely arranged Alu repeats and MADE1 mariners. The remaining LIRs are mostly unique in their sequence features. Comparative studies of human, chimpanzee, rhesus monkey and mouse orthologous genes reveal that human genes have more recombinogenic LIRs than other orthologs, and over 80% are human-specific. The human genes associated with the human-specific LIRs are involved in the pathways of cell communication, development and the nervous system, as based on significantly over-represented Gene Ontology terms. The functional pathways related to the development and functions of the nervous system are not enriched in chimpanzee and mouse orthologs. The findings of the present study provide insight into the role of intronic LIRs in gene regulation and primate speciation. [source] Oosp1 encodes a novel mouse oocyte-secreted proteinGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 3 2001Changning Yan Abstract Summary: Oocyte-somatic cell communication is necessary for normal ovarian function. However, the identities of the majority of oocyte-secreted proteins remain unknown. A novel cDNA encoding mouse oocyte- secreted protein 1 (OOSP1) was identified using a modified subtractive hybridization screen. The Oosp1 cDNA encodes a 202-amino acid protein that contains a 21-amino acid signal peptide sequence, 5 putative N-linked glycosylation consensus sequences, and 6 cysteines that are predicted to form 3 disulfide bonds. OOSP1 shares amino acid identity with placental-specific protein 1 (PLAC1), a secreted protein expressed in the placenta and the ectoplacental cone. The Oosp1 mRNA is approximately 1.0 kb and is present at high levels in the oocytes of adult ovaries and at lower levels in the spleen. The mouse Oosp1 gene is 5 exons, spans greater than 16.4 kb, and localizes to chromosome 19 at a position that shares synteny with human chromosome 11q12,11q13. The identification of OOSP1 as a new oocyte-secreted protein permits future in vitro and in vivo functional analyses to define its role in ovarian folliculogenesis. genesis 31:105,110, 2001. © 2001 Wiley-Liss, Inc. [source] Upregulation of the tumor suppressor gene menin in hepatocellular carcinomas and its significance in fibrogenesis,HEPATOLOGY, Issue 5 2006Pierre J. Zindy The molecular mechanisms underlying the progression of cirrhosis toward hepatocellular carcinoma were investigated by a combination of DNA microarray analysis and literature data mining. By using a microarray screening of suppression subtractive hybridization cDNA libraries, we first analyzed genes differentially expressed in tumor and nontumor livers with cirrhosis from 15 patients with hepatocellular carcinomas. Seventy-four genes were similarly recovered in tumor (57.8% of differentially expressed genes) and adjacent nontumor tissues (64% of differentially expressed genes) compared with histologically normal livers. Gene ontology analyses revealed that downregulated genes (n = 35) were mostly associated with hepatic functions. Upregulated genes (n = 39) included both known genes associated with extracellular matrix remodeling, cell communication, metabolism, and post-transcriptional regulation gene (e.g., ZFP36L1), as well as the tumor suppressor gene menin (multiple endocrine neoplasia type 1; MEN1). MEN1 was further identified as an important node of a regulatory network graph that integrated array data with array-independent literature mining. Upregulation of MEN1 in tumor was confirmed in an independent set of samples and associated with tumor size (P = .016). In the underlying liver with cirrhosis, increased steady-state MEN1 mRNA levels were correlated with those of collagen ,2(I) mRNA (P < .01). In addition, MEN1 expression was associated with hepatic stellate cell activation during fibrogenesis and involved in transforming growth factor beta (TGF-,),dependent collagen ,2(I) regulation. In conclusion, menin is a key regulator of gene networks that are activated in fibrogenesis associated with hepatocellular carcinoma through the modulation of TGF-, response. (HEPATOLOGY 2006;44:1296,1307.) [source] Nitric oxide in inflammatory bowel disease: a universal messenger in an unsolved puzzleIMMUNOLOGY, Issue 4 2004George Kolios Summary In recent years, nitric oxide (NO), a gas previously considered to be a potentially toxic chemical, has been established as a diffusible universal messenger that mediates cell,cell communication throughout the body. Constitutive and inducible NO production regulate numerous essential functions of the gastrointestinal mucosa, such as maintenance of adequate perfusion, regulation of microvascular and epithelial permeability, and regulation of the immune response. Up-regulation of the production of NO via expression of inducible nitric oxide synthase (iNOS) represents part of a prompt intestinal antibacterial response; however, NO has also been associated with the initiation and maintenance of inflammation in human inflammatory bowel disease (IBD). Recent studies on animal models of experimental IBD have shown that constitutive and inducible NO production seems to be beneficial during acute colitis, but sustained up-regulation of NO is detrimental. This fact is also supported by studies on mice genetically deficient in various NOS isoforms. However, the mechanism by which NO proceeds from being an indispensable homeostatic regulator to a harmful destructor remains unknown. Furthermore, extrapolation of data from animal colitis models to human IBD is questionable. The purpose of this review is to update our knowledge about the role of this universal mediator and the enzymes that generate it in the pathogenesis of IBD. [source] Escape from microenvironmental control and progression of intraepithelial neoplasiaINTERNATIONAL JOURNAL OF CANCER, Issue 6 2005Weitian Zhang Abstract We previously reported that normal human keratinocytes controlled neoplastic progression of tumor cells at an early stage of transformation in stratified squamous epithelium. We now studied if cells at a more advanced stage of transformation were also subject to such microenvironmental control. To accomplish this, 3D human tissues that mimic intraepithelial neoplasia were fabricated by mixing genetically marked (,-gal), early-stage (II-4 cells) or advanced-stage (SCC13) transformed keratinocytes with normal keratinocytes, and tumor cell fate and phenotype were monitored in organotypic culture and after surface transplantation to nude mice. In vivo, SCC13 cells evaded local growth suppression to undergo connective tissue invasion at significantly lower tumor cell volumes (12:1, 50:1 normal:tumor cells) than II-4 cells. This behavior was explained by the growth suppression of II-4 cells, while advanced-stage tumor cells escaped this control and continued to undergo clonal expansion in mixed cultures to form large, intraepithelial tumor clusters. These communities of tumor cells underwent autonomous growth that was associated with altered expression of markers of differentiation (keratin 1) and cell,cell communication (connexin-43). Furthermore, significantly greater numbers of SCC13 cells expanded into a basal position after low-calcium stripping of suprabasal cells of mixed cultures compared to II-4 cells, suggesting that expansion of these cells enabled tumor cell invasion after transplantation. These findings demonstrated that early tumor development in human stratified squamous epithelium required escape from microenvironmental growth control that was dependent on the transformation stage of intraepithelial tumor cells during the premalignant stage of cancer progression. © 2005 Wiley-Liss, Inc. [source] A keratinocytes,melanocytes coculture system for the evaluation of active ingredients' effects on UV-induced melanogenesisINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1-2 2003J.-F. Nicolaÿ Synopsis A new experimental design, more reliable for in vitro testing of active ingredients' effect on ultraviolet (UV)-induced melanogenesis has been carried out. It uses a bicompartmental coculture system where cell communication between keratinocytes and melanocytes can take place. Thus, this experimental situation enables to monitor the effect of biological agents released by both cell types on melanogenesis and the interference of tested compounds with this ,paracrine linkage'. Experiments with UVB-irradiated cocultures show the importance of cell communication in the melanogenic response. In this model, the endogenous mediator, nitric oxide (NO), increased melanin production. Different compounds were tested in the coculture system, and comparison with data obtained from irradiated monocultures of melanocytes enables to distinguish a specific effect on cell communication. In addition, this more close-to-reality experimental model proved to provide a valuable first approach for the assessment of the ,bioavailability' of the tested substances. Finally, the effect of an innovative photoprotective agent capable of ,boosting' UV-induced melanogenic cell communication is presented. Résumé Un nouveau concept expérimental, plus fiable pour l,évaluation in vitro de l,effet de principes actifs sur la mélanogénèse induite par les UV, a été mis en ,uvre. Il utilise un système de co-culture à double compartiment dans lequel une communication cellulaire entre les kératinocytes et les mélanocytes peut s,établir. Ainsi, ce système expérimental permet de suivre l,effet des agents biologiques libérés par les deux types de cellules sur la mélanogénèse, et les interférences des composés testés avec ce ,lien paracrine'. Les essais avec des co-cultures irradiées aux UV montrent l,importance de la communication cellulaire dans la réponse mélanogénique. Avec ce modèle, le médiateur oxyde nitrique endogène (NO) augmente la production de mélanine. Différents composés ont été testés avec ce système de co-culture, et une comparaison avec les données obtenues à partir de monocultutres de mélanocytes irradiées permet de distinguer un effet spécifique sur la communication cellulaire. En outre, ce modèle expérimental plus proche de la réalité s,est avéré apporter une première approche valable de l,évaluation de la ,biodisponibilité' des substances testées. Enfin, l,effet d,un agent protecteur innovant capable de stimuler la communication cellulaire mélanogénique induite par les UV est décrit. [source] Identification of genes related to mechanical stress in human periodontal ligament cells using microarray analysisJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2007R. M. S. De Araujo Background and Objective:, Differential expression of genes in human periodontal ligament (PDL) under mechanical stress, such as orthodontic force, is thought to be involved in the remodeling of PDL cells and periodontal tissues. However, little is known about the genes expressed in PDL cells under mechanical stress. Material and Methods:, We employed microarray analysis to assess, in a comprehensive manner, the gene expression profiles in PDL cells compressed by a static force using an in vitro three-dimensional culture system. Six genes were selected and validated by quantitative real-time polymerase chain reaction analysis, consistent with the microarray data. Results:, The microarray data revealed that 108 of 30,000 genes tested were differentially expressed by mechanical force loading. Among them, 85 genes were up-regulated by mechanical stress, while 23 genes were down-regulated, judging by the thresholds of a two-fold increase/decrease compared with the controls. Thirty-two of the up-regulated and eight of the down-regulated genes, well-characterized in protein function, were involved in numerous biological processes including cell communication, cell signaling, cell cycle, stress response, and calcium release. However, several genes differentially expressed in our microarray data have not been well defined as stress-response molecules. Conclusion:, Our microarray is the first to show the gene profile in PDL cells caused by mechanical stress; however, further studies to clarify the physiological function of these molecules in PDL cells are required. [source] Co-culture in cartilage tissue engineeringJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 3 2007Jeanine Hendriks Abstract For biotechnological research in vitro in general and tissue engineering specifically, it is essential to mimic the natural conditions of the cellular environment as much as possible. In choosing a model system for in vitro experiments, the investigator always has to balance between being able to observe, measure or manipulate cell behaviour and copying the in situ environment of that cell. Most tissues in the body consist of more than one cell type. The organization of the cells in the tissue is essential for the tissue's normal development, homeostasis and repair reaction. In a co-culture system, two or more cell types brought together in the same culture environment very likely interact and communicate. Co-culture has proved to be a powerful in vitro tool in unravelling the importance of cellular interactions during normal physiology, homeostasis, repair and regeneration. The first co-culture studies focused mainly on the influence of cellular interactions on oocytes maturation to a pre-implantation blastocyst. Therefore, a brief overview of these studies is given here. Later on in the history of co-culture studies, it was applied to study cell,cell communication, after which, almost immediately as the field of tissue engineering was recognized, it was introduced in tissue engineering to study cellular interactions and their influence on tissue formation. This review discusses the introduction and applications of co-culture systems in cell biology research, with the emphasis on tissue engineering and its possible application for studying cartilage regeneration. Copyright © 2007 John Wiley & Sons, Ltd. [source] ACTH and adrenocortical gap junctionsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2003Sandra A. Murray Abstract Since the initial identification of gap junctions in the adrenal gland, it has been proposed that a system involving direct cell,cell communication might be involved in adrenal cortical functions. Gap junction channels do, in fact, provide pathways for direct intercellular exchange of small molecules (<1,000 Da), many of which have the potential to influence a wide range of cellular activities. Gap junctions are composed of proteins called connexin which, in the adrenal cortex, have proven to be remarkably consistent in both type and zonal distribution with connexin 43 (Cx43) as the predominant component in mammalian adrenal glands thus far evaluated. Only the inner two zones of the cortex (zonae fasciculata and reticularis) exhibit significant amounts of Cx43 and functional coupling. Adrenocorticotropin (ACTH) has been shown to increase Cx43 protein in vivo and in vitro, and a strong correlation has been noted between the presence of gap junctions and certain adrenal cortical functions, especially steroidogenic capacity and cell proliferation. This review summarizes evidence of the Cx43 expression in adrenal cortical cells and the likely role of Cx43 in steroidogenesis and cell proliferation. It is concluded that control of gap junction expression in the adrenal gland is hormonally dependent and is functionally linked to adrenal gland zonation. Microsc. Res. Tech. 61:240,246, 2003. © 2003 Wiley-Liss, Inc. [source] Cell,cell communication in filamentous cyanobacteriaMOLECULAR MICROBIOLOGY, Issue 4 2008Robert Haselkorn Summary Although cytoplasmic bridges between adjacent cells in the filaments of nitrogen-fixing cyanobacteria have been known for decades, the existence also of a continuous periplasm along the filaments raised the possibility that alternative modes of communication between cells could be utilized. The latter hypothesis was investigated by using GFP fusions to proteins whose expression is cell-specific and engineered to be transported into the periplasm. Two groups have recently obtained contradictory results, one supporting periplasmic transport of GFP from cell to cell, the other not. A third effort, involving members of the first group, used a smaller, soluble fluorophore and found rapid communication via the cytoplasmic bridges between cells. The dilemma of periplasmic diffusion remains unresolved. [source] Emerging Concepts in the Pathophysiology of Type 2 Diabetes MellitusMOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 3 2009Prasanth N. Surampudi MD Abstract Type 2 diabetes mellitus is a multifactorial metabolic disorder. It is characterized by chronic hyperglycemia, insulin resistance, and a relative insulin secretion defect. The prevalence of type 2 diabetes mellitus has risen worldwide in large part because of an increase in obesity and sedentary lifestyles. The underlying pathophysiology and complications of type 2 diabetes mellitus are still being elucidated. Recent advances in diabetes research have helped us to gain a better understanding about insulin resistance and insulin secretion defects. The evolving understanding about the influence of the incretin effect, insulin signal transduction, adipose tissue, intra,islet cell communication, and inflammation is changing the way in which we view type 2 diabetes mellitus. This new understanding will eventually provide us with new treatment approaches to help patients who have type 2 diabetes mellitus. This article gives a review of the current and emerging concepts of the pathophysiology of type 2 diabetes mellitus. Mt Sinai J Med 76: 216,226, 2009. © 2009 Mount Sinai School of Medicine [source] REVIEW ARTICLE: The Role of Placental Exosomes in ReproductionAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010Lucia Mincheva-Nilsson Citation Mincheva-Nilsson L, Baranov V. The Role of Placental Exosomes in Reproduction. Am J Reprod Immunol 2010 Cell communication comprises cell,cell contact, soluble mediators and intercellular nanotubes. There is, however, another cell,cell communication by released membrane-bound microvesicles that convey cell,cell contact ,by proxy' transporting signals/packages of information from donor to recipient cells locally and/or at a distance. The nanosized exosomes comprise a specialized type of microvesicles generated within multivesicular bodies (MVB) and released upon MVB fusion with the plasma membrane. Exosomes are produced by a variety of immune, epithelial and tumor cells. Upon contact, exosomes transfer molecules that can render new properties and/or reprogram their recipient cells. Recently, it was discovered that the syncytiotrophoblast constitutively and throughout the pregnancy secretes exosomes. The placenta-derived exosomes are immunosuppressive and carry proteins and RNA molecules that in a redundant way influence a number of mechanisms and promote the fetal allograft survival. In this review, we summarize the current knowledge on the nature of placenta-derived exosomes and discuss their role in pregnancy. [source] The cytoskeleton and diseaseTHE JOURNAL OF PATHOLOGY, Issue 4 2004Frans CS Ramaekers Abstract Cytoskeletal research in recent years has revolutionized cell biology and biomedicine. The cytoskeleton spans the cytoplasm and interconnects the cell nucleus with the extracellular matrix, thereby forming a structural link between molecules involved in cell communication on the one hand, and gene expression on the other. Since the cytoskeleton is involved in virtually all cellular processes, abnormalities in this essential cellular component frequently result in disease. In this introduction, the basic structure of the cytoskeleton is briefly outlined. Furthermore, the disease processes in which the cytoskeleton plays a decisive role, and which are reviewed in detail in the papers in this issue, are briefly introduced. The advances in our understanding of the cytoskeleton and its function in disease will lead to new diagnostic and therapeutic applications in the foreseeable future. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Morphology of Canine Cumulus,Oocyte Complexes in Pre-pubertal BitchesANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2003A. Haenisch-Woehl Summary The morphology of canine cumulus,oocyte complexes (COCs) before puberty is still unknown. Therefore, the aim of our study was to elucidate the morphological characteristics of pre-pubertal oocytes and cumulus cells by light microscopy, scanning electron microscopy and transmission electron microscopy. The pre-pubertal oocyte was characterized by accumulation of lipid yolk droplets in the cytoplasm as well as high energy metabolism, low protein synthesis and high transcriptional activity of the cumulus cells. The cumulus cells, which revealed a prominent nucleus and few cytoplasm, communicated with each other by few short processes and exhibited merely a small amount of processes reaching the oocyte. Our studies imply that both the oocyte and the cumulus cells of canine COCs before puberty reveal characteristic morphological features which are correlated with changes in oocyte metabolism and cumulus cell communication. [source] Co-ordinating innate and adaptive immunity to viral infection: mobility is the keyAPMIS, Issue 5-6 2009JEANETTE ERBO CHRISTENSEN The host counters a viral infection through a complex response made up of components belonging to both the innate and the adaptive immune system. In this report, we review the mechanisms underlying this response, how it is induced and how it is co-ordinated. As cell,cell communication represents the very essence of immune system physiology, a key to a rapid, efficient and optimally regulated immune response is the ability of the involved cells to rapidly shift between a stationary and a mobile state, combined with stringent regulation of cell migration during the mobile state. Through the co-ordinated recruitment of different cell types intended to work in concert, cellular co-operation is optimized particularly under conditions that may involve rare cells. Consequently, a major focus is placed on presenting an overview of the co-operative events and the associated cell migration, which is essential in mounting an efficient host response and co-ordinating innate and adaptive immunity during a primary viral infection. [source] Connexin abundance in resistance vessels from the renal microcirculation in normo- and hypertensive ratsAPMIS, Issue 4 2009THOMAS HARTIG BRAUNSTEIN The expression of connexins in renal arterioles is believed to have a profound impact on conducted responses, regulation of arteriolar tonus and renal blood flow. We have previously shown that in renal preglomerular arterioles, conducted vasomotor responses are 40% greater in spontaneously hypertensive rats (SHR) than in normotensive Sprague,Dawley (SD) rats. Because conducted vasomotor responses depend on the cell,cell communication mediated through gap junctions, we hypothesized that the increased magnitude of conducted vasomotor response in SHR is associated with an increased amount of connexins in renal arterioles. To test this hypothesis, the amount of connexin 37 (Cx37), Cx40 and Cx43 was assessed in renal arterioles from normo- and hypertensive rats using quantitative immunofluorescence laser confocal miscroscopy. To account for differences in genetic background, we included both normotensive Wistar,Kyoto (WKY) and SD rats in the study. In all three strains of rats, and for all three isoforms, the expression of connexins was predominantly confined to the endothelial cells. We found a significantly increased abundance (240 ± 17.6%, p<0.05) of Cx37 in arterioles from WKY compared with SD and SHR. This high abundance of Cx37 was not related to blood pressure because normotensive SD demonstrated a level of Cx37 similar to that of SHR. Additionally, we found no evidence for an increased abundance of Cx40 and Cx43 in renal arterioles of SHR when compared with normotensive counterparts. [source] Purification, crystallization and preliminary characterization of an Eph-B2/ephrin-B2 complexACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2002Juha-P. Eph receptors and their ephrin ligands are involved in various aspects of cell,cell communication during development, including those of the axon pathfinding processes in the nervous system and cell,cell interactions of the vascular endothelial cells. The recognition and binding properties of the ligand-binding domain of EphB2 receptor and the extracellular domain of ephrin-B2 have been studied and two different cocrystals of their complex have been generated. One crystal form has space group C2, diffracts to 3.5,Å and has unit-cell parameters a = 128, b = 88, c = 79,Å, , = 112°. The other crystal form grows in space group P1, has unit-cell parameters a = 78, b = 78, c = 78,Å, , = 69, , = 75, , = 69° and diffracts to 2.7,Å. Structure-determination experiments using the latter form are in progress. The structure of the complex will elucidate the chemical nature of the interactions between Eph receptors and ephrins, which would create the possibility of using them as targets for structure-based anticancer-drug development. [source] Crystallization and preliminary X-ray analysis of mouse RANK and its complex with RANKLACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2009Thomas S. Walter The interaction between the TNF-family molecule receptor activator of NF-,B ligand (RANKL) and its receptor RANK induces osteoclast formation, activation and survival in the process of bone remodelling. RANKL,RANK also plays critical roles in T-cell/dendritic cell communication and lymph-node formation and in a variety of pathologic conditions such as tumour-cell migration and bone metastasis. Both the ectodomain of mouse RANKL and the extracellular domain of mouse RANK have been cloned, expressed and purified. Crystals of RANK alone and of RANK in complex with RANKL have been obtained that are suitable for structure determination. [source] A dynamic model for diauxic growth, overflow metabolism, and AI-2-mediated cell,cell communication of Salmonella Typhimurium based on systems biology conceptsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2009Astrid M. Cappuyns Abstract The last decades, the research on bacterial cell,cell communication or quorum sensing has been quite intense. Quorum sensing allows bacteria to coordinate their behavior and to act as one entity. Quorum sensing controls microbiological functions of medical, agricultural and industrial importance and a better understanding of the underlying mechanisms and the conditions under which the signaling occurs, offers possibilities for new applications. In this article a dynamic model for diauxic growth, overflow metabolism and AI-2-mediated cell,cell communication of Salmonella Typhimurium is presented. The growth, and the production and uptake of the AI-2 signaling molecule of S. Typhimurium are investigated in a controlled environment (bioreactor). In a first stage a model is developed to describe diauxic growth and overflow metabolism. This model is extended in a second stage to describe AI-2 dynamics of S. Typhimurium in relation to the growth kinetics and biomass concentration. It is illustrated how this model can be employed to test hypotheses concerning AI-2 dynamics on the basis of macroscopic data. Biotechnol. Bioeng. 2009;102: 280,293. © 2008 Wiley Periodicals, Inc. [source] Stimulation of cardiac ,-adrenoceptors targets connexin 43BRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2009Kerstin Boengler Connexin 43 (Cx43) is the major protein of cardiac ventricular gap junctions and is crucial to cell,cell communication and cardiac function. The protein level of Cx43 is reduced in patients with heart failure or dilated cardiomyopathy (DCM), pathophysiological conditions often associated with arrhythmias. As catecholamines are often increased in cardiac diseases, Salameh et al., in this issue of the BJP, investigated the effect of ,-adrenoceptor stimulation of neonatal cardiomyocytes on Cx43 expression and found increased Cx43 mRNA and protein levels following 24 h stimulation. Up-regulation of Cx43 was associated with phosphorylation of mitogen-activated protein kinases and translocation of transcription factors into the nucleus. In patients with DCM, a situation often associated with desensitization of the ,-adrenoceptor system, Cx43 expression was reduced. The characterization of the signal transduction pathways involved in Cx43 expression and intracellular localization in human myocardium in vivo is a promising target for the development of new anti-arrhythmic strategies. [source] Carbohydrate-Encapsulated Gold Nanoparticles for Rapid Target-Protein Identification and Binding-Epitope MappingCHEMBIOCHEM, Issue 7 2005Yu-Ju Chen Dr. Carbohydrate,lectin recognition plays important roles in cell,cell communication, proliferation, and differentiation. We report here a new approach of using a carbohydrate-encapsulated gold nanoparticle (shown in purple) as an affinity probe for the efficient separation and enrichment of target proteins, and then protein identification and epitope mapping by MALDI-TOF MS. [source] Towards a new classification of ectodermal dysplasiasCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 4 2003J. Lamartine Summary Ectodermal dysplasias (EDs) constitute a large and complex group of diseases characterized by various defects in hair, nails, teeth and sweat glands. Of the 170 EDs described so far, fewer than 30 have been explained at the molecular level with identification of the causative gene. This review proposes a new classification of EDs based on the function of the protein encoded by the mutated gene. The EDs are reviewed in light of the recent molecular and biochemical findings and an attempt is made to classify ED causative genes into four major functional subgroups: cell,cell communication and signalling; adhesion; transcription regulation; and development. [source] | ||||||||||||||||||||||||||||