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PubMedDate not supplied

Micropatterning of nanoengineered surfaces to study neuronal cell attachment in vitro.

Methods for producing protein patterns with defined spatial arrangement and micro- and nanoscale features are important for studying cellular-level interactions, including basic cell-cell communications, cell signaling, and mechanisms of drug action. Toward this end, a straightforward, versatile procedure for fabricating micropatterns of bioactive nanofilm coatings as multifunctional biological testbeds is demonstrated. The method, based on a combination of photolithography and layer-by-layer self-assembly (LbL), allows for precise construction of nanocomposite films of potentially complex architecture, and patterning of these films on substrates using a modified lift-off (LO) procedure. As a first step in evaluating nanostructures made with this process, "comparison chips," comprising two coexisting regions of square patterns with relevant proteins/polypeptides on a single substrate, were fabricated with poly(diallyldimethylammonium chloride) (PDDA) as a cell-repellent background. Using neuronal cells as a model biological system, comparison chips were produced with secreted phospholipase A2 (sPLA2), a known membrane-active enzyme for neurons, for direct comparison with gelatin, poly-l-lysine (PLL), or bovine serum albumin (BSA). Fluorescence microscopy, surface profilometry, and atomic force microscopy techniques were used to evaluate the structural properties of the patterns on these chips and show that the patterning technique was successful. Preliminary cell culture studies show that neurons respond and bind specifically to the sPLA2 enzyme embedded in the polyelectrolyte thin films and present as the outermost layer. These findings point to the potential for this method to be applied in developing test substrates for a broad array of studies aimed at identifying important biological structure-function relationships.

Animals↗
PubMed1995

Glomerular actions of nitric oxide.

NO, a simple molecule synthesized from L-arginine by NO synthases, has been identified to play an important role in cell communication, cell defense and cell injury. The half life of NO is very short because NO either reacts with superoxide anion (O2-), and/or binds to heme molecules or Fe-S groups present in proteins. The biological effects of NO depend on both the concentration of NO at the site of action as well as upon the specific location where NO is generated. Small quantities of NO are generated by cNOS such as that present in the vascular endothelium, while large quantities of nitric oxide are synthesized by iNOS in response to cytokines or bacterial products. Within the kidney NO generated by endothelial cNOS participates in the regulation of the glomerular microcirculation by modifying the tone of the afferent arteriole and mesangial cells (Fig. 4). In addition, NO generated by macula densa and the afferent arteriole control glomerular hemodynamics via TGF and by modulating renin release. Therefore NO is important in the physiologic regulation of glomerular capillary blood pressure, glomerular plasma flow and the glomerular ultrafiltration coefficient. Through its actions on glomerular pressures and flows, NO may also regulate the macro- and micromolecular traffic through the mesangium. Chronic NO insufficiency causes hypertension and glomerular damage and may be causally involved in the genesis of salt dependent hypertension. Increased NO production may be involved in the early pathogenic hemodynamic changes in diabetes and in the physiologic hemodynamic responses to normal pregnancy. Maintenance of the antithrombogenic properties of the endothelium is another important action of NO which inhibits platelet aggregation and adhesion. Large quantities of NO such as that synthesized by either glomerular cells or macrophages during glomerular inflammation may lead to glomerular injury. A better understanding of the physiology and pathophysiology of NO in the kidney will lead to the development of new therapeutic avenues.

Animals↗
PubMed1999

Lysophosphatidylcholine up-regulates IL-1 beta-induced iNOS expression in rat mesangial cells.

BACKGROUND: Nitric oxide (NO), a simple molecule synthesized from L-arginine by NO synthases (NOS), has been identified to play an important role in cell communication, cell defense and cell injury. Several studies have shown that glomeruli from rats with immune-mediated glomerular inflammation have increased production of NO. Recently, it was also reported that inducible NOS (iNOS) is localized in mesangial cells, glomerular epithelial cells and infiltrating cells in the diseased human glomeruli. On the other hand, while oxidized low density lipoprotein (ox-LDL) has been suggested to be related to progression of glomerular disease, the mechanism remains unknown. We investigated the effect of lysophosphatidylcholine (LPC), a modified phospholipid produced during LDL oxidation, on iNOS expression in rat mesangial cells. METHODS AND RESULTS: Treatment of mesangial cells with interleukin-1 beta (IL-1 beta) induced iNOS activity measured as nitrite levels in cell culture supernatants. Treatment with LPC had no effect. In contrast, coincubation with LPC and IL-1 beta resulted in a markedly higher nitrite content compared to that after incubation with IL-1 beta alone. Western blot analysis revealed that LPC caused a significant increase in the formation of iNOS protein in the presence of IL-1 beta. CONCLUSION: These findings suggest that LPC may contribute to progression of glomerular inflammation by augmenting IL-1 beta-induced iNOS expression.

Animals↗
PubMed2006

Expression profiling of radiation-induced genes in radiodermatitis of hairless mice.

BACKGROUND: Radiation induces many cellular events leading to radiodermatitis. OBJECTIVES: The aim of this study was to establish a radiodermatitis model using experimental animals, and to examine the expression profile of radiation-induced genes. METHODS: Hairless mice were irradiated on the dorsal skin; then total RNAs were isolated and microarray hybridizations were performed. RESULTS: Irradiation with a total of 40 Gy (10 Gy day-1 for four consecutive days) provokes radiodermatitis in the hairless mouse. After microarray analysis, 130 genes that showed upregulation by radiation were selected and organized into four different clusters, depending on the time-kinetic pattern. Classification of these genes into several functional categories revealed that various biological processes were globally affected by radiation. These include transcription regulation, signal transduction, cell communication, cell death regulation and metabolism. CONCLUSIONS: These results demonstrate the complexity of the transcriptional profile of the radiation response, providing important clues on which to base further investigations of the molecular events underlying radiodermatitis.

Animals↗
PubMed2006

Strategies of aerobic ammonia-oxidizing bacteria for coping with nutrient and oxygen fluctuations.

In most natural environments as well as in engineered environments, such as wastewater treatment plants, ammonia-oxidizing bacteria (AOB) experience fluctuating substrate concentrations. Several physiological traits, such as low maintenance energy demand and decay rate, cell-to-cell communication, cell mobility, stable enzymes and RNAs, could allow AOB to maintain themselves under unfavourable circumstances. This review examines whether AOB possess such traits and how these traits might offer advantages over competing organisms such as heterotrophic bacteria during periods of starvation. In addition, within the AOB groups, differences exist in adaptation to and competitiveness under conditions of high or low ammonia or oxygen concentrations. Because these findings are of importance with regard to the ecology and activity of AOB in natural and engineered environments, concluding remarks are directed towards future research objectives that may clarify unanswered questions, thereby contributing to the general knowledge of the ecology and activity of ammonia oxidizers.

Ammonia↗
PubMed2005

Genome-wide transcriptional analysis of carboplatin response in chemosensitive and chemoresistant ovarian cancer cells.

We have recently described an ex vivo chemoresponse assay for determining chemosensitivity in primary cultures of human tumors. In this study, we have extended these experiments in an effort to correlate chemoresponse data with gene expression patterns at the level of transcription. Primary cultures of cells derived from ovarian carcinomas of individual patients (n=6) were characterized using the ChemoFx assay and classified as either carboplatin sensitive (n=3) or resistant (n=3). Three representative cultures of cells from each individual tumor were then subjected to Affymetrix gene chip analysis (n=18) using U95A human gene chip arrays. Data were analyzed using the dCHIP software package. We identified a significant number of genes whose expression patterns were altered between carboplatin chemosensitive and chemoresistant cells, in normal culture conditions and in the presence of carboplatin for either 2 or 72 hours. Among these differentially expressed genes, we found a significant proportion to be associated with apoptosis, cell-cell communication, cell adhesion, DNA repair, and cell proliferation. In general, the molecular phenotype displayed by chemoresistant cells was reflective of an extended life span in culture in the presence of carboplatin and the genes that define this phenotype are potential biomarkers for the prognostic management of ovarian cancer patients.

Antineoplastic Agents↗
PubMed2004

Gene expression analysis in human gastric cancer cell line treated with trichostatin A and S-adenosyl-L-homocysteine using cDNA microarray.

Trichostatin A (TSA) and S-adenosyl-L-homocysteine (AdoHcy) have been reported to affect histone modifications. To investigate the effects of two drugs that can reportedly affect chromatin remodeling, we analyzed the gene expression profiles of TSA and AdoHcy in a gastric cancer cell line using 14 K cDNA microarray. The significant analysis of microarray (SAM) identified 98 and 43 differentially expressed genes in TSA and AdoHcy treated sets, respectively, and selected genes were functionally classified. In the gastric cancer cell line, genes related to cell communication, cell growth/maintenance, and morphogenesis were highly expressed with TSA, and genes with cell growth/maintenance, metabolism, oxidoreductase activity were upregulated with AdoHcy. Genes downregulated with TSA included those controlling the cell cycle, cell growth/proliferation, DNA binding, and metabolism, whereas genes involved in calcium signaling, cell growth/proliferation, and metabolism were downregulated with AdoHcy. Furthermore, we identified the genes commonly expressed in both drug treatments. Compared to TSA, AdoHcy did not induce apoptosis in the SNU-16 gastric cancer cell line, and RT-PCR was performed for selective genes to confirm the microarray data. This gene expression profile analysis with TSA and AdoHcy should contribute to a greater understanding of the molecular mechanism of chromatin remodeling and cancer, and provide candidate genes for further studies involving the roles of histone modifications in gastric cancer.

Acetylation↗
PubMed2006

Generation and analysis of expressed sequence tags from Botrytis cinerea.

Botrytis cinerea is a filamentous plant pathogen of a wide range of plant species, and its infection may cause enormous damage both during plant growth and in the post-harvest phase. We have constructed a cDNA library from an isolate of B. cinerea and have sequenced 11,482 expressed sequence tags that were assembled into 1,003 contigs sequences and 3,032 singletons. Approximately 81% of the unigenes showed significant similarity to genes coding for proteins with known functions: more than 50% of the sequences code for genes involved in cellular metabolism, 12% for transport of metabolites, and approximately 10% for cellular organization. Other functional categories include responses to biotic and abiotic stimuli, cell communication, cell homeostasis, and cell development. We carried out pair-wise comparisons with fungal databases to determine the B. cinerea unisequence set with relevant similarity to genes in other fungal pathogenic counterparts. Among the 4,035 non-redundant B. cinerea unigenes, 1,338 (23%) have significant homology with Fusarium verticillioides unigenes. Similar values were obtained for Saccharomyces cerevisiae and Aspergillus nidulans (22% and 24%, respectively). The lower percentages of homology were with Magnaporthe grisae and Neurospora crassa (13% and 19%, respectively). Several genes involved in putative and known fungal virulence and general pathogenicity were identified. The results provide important information for future research on this fungal pathogen.

Botrytis↗
PubMed2002

Human cardiac valve interstitial cells in collagen sponge: a biological three-dimensional matrix for tissue engineering.

BACKGROUND AND AIM OF STUDY: The use of a biological, biodegradable scaffold remodeled by cells to resemble a valve leaflet is an attractive approach to tissue engineering. The study aim was to evaluate the suitability of a three-dimensional biodegradable collagen sponge for maintenance of cell viability, proliferation and phenotype of cultured human cardiac valve interstitial cells (ICs). METHODS: Pieces of valve leaflets were snap-frozen, sectioned and stained by immunoperoxidase. Interstitial cells were cultured from cardiac valves and plated onto glass coverslips or seeded in collagen sponge, then stained by immunofluorescence or immunoperoxidase. A panel of antibodies was used to determine cell phenotype. Cell viability was assessed using a dye-based cell proliferation assay, and cell death by lactate dehydrogenase measurement. RESULTS: ICs variably expressing the phenotypic markers were found throughout the native valve leaflet, but particularly on the ventricular side. Cultured ICs either on coverslips or in collagen sponge expressed vimentin, a fibroblast surface antigen and variable amounts of smooth muscle (SM) alpha-actin. Expression of the other phenotypic markers, SM myosin, desmin and prolyl 4-hydroxylase differed: interestingly, the ratio of cells in collagen sponge expressing these markers reflected that found in the native valve leaflet. Confocal microscopy of ICs in the collagen sponge revealed the presence of cells with long interconnecting extensions indicating cell communication. Cell proliferation and cell death assays established that cells were not only viable after four weeks in the sponge, but were also proliferating. CONCLUSION: This study demonstrates that collagen sponge is a suitable biodegradable scaffold that can maintain viable valve ICs and appears to enhance the capacity of the cell to express its original phenotype.

Biological Products↗
PubMed2005

[Differentially expressed gene profiles of cochlea in rats induced by acute and chronic sodium salicylate injection].

OBJECTIVE: To study the mechanism of electrophysiologic changes caused by different type of sodium salicylate injection. METHODS: Decapitated three group rats ( acute injected, chronic injected and normal rats ) separately, dissected the temporal bones to collect cochlea, and the otic capsules were removed. Then the cochlear materials from each groups were pooled and homogenized respectively, extracted the total RNA, obtained cDNA from purified total RNA by reversed transcription, cDNA were transcripted to cRNA probes in vitro. Hybridized the cRNA probes with tester chip to evaluate the quality of probes, if good, hybridized the probes with real chip. Obtained three gene expression profiles of different groups of cochlea Analyzed the differentially expressed genes among three groups by SOM. Analogized the SOM result to electrophysiologic changes. Then analyzed the genes in clusters of analog results by Gene Ontology. Then the genes in clusters of analog results were analyzed by Gene Ontology. Hsp27 was chosen to validate the result of gene chip using real time quantitative reverse transcription PCR ( RTQ RT-PCR). RESULTS: The probes was good, and the chip hybridization results was credible. We obtained 6 clusters genes by SOM analysis, in which we choose cluster 3 and cluster 4 as candidate cluster. There were 46 genes in cluster 3 and 30 genes in cluster 4 employing GO analysis, which involved in cell communication, cell motility, metabolism, immune response and nerve ensheathment, et al. The result of RTQ RT-PCR showed high concordance with that of gene chip. CONCLUSION: It's a new method to study the mechanism of electrophysiologic changes caused by sodium salicylate by gene chip and SOM analysis.

Animals↗
PubMed1991

Histo-blood group antigens in cancer.

Cell surface carbohydrates undergo dramatic changes in cancer. Changes in histo-blood group antigens result from either blocked synthesis with a precursor accumulation of oligosaccharide chain, or neosynthesis caused by the activation of 'silent' glycosyl transferases. Carbohydrate antigens play a crucial role in cell-cell communication, cell growth and differentiation. Although the biological significance of tumor-associated carbohydrate changes is not completely understood, these may provide the basis for uncontrolled cell growth, invasiveness and metastatic potential. Monoclonal antibodies developed against a variety of tumor cells have been identified as being directed against different carbohydrate antigens. Carbohydrate antigens and anti-carbohydrate antibodies are being used to develop diagnostic and therapeutic strategies for cancer.

ABO Blood-Group System↗
PubMed1995

Sepsis-related alterations in non-immune cell-signaling.

Traditionally, sepsis is defined as a systemic inflammatory reaction of the organism to Gram-negative bacterial leading to septic shock--characterized by hemodynamic derangements--and eventually to septic multi-organ malfunction. Sepsis syndrome is diagnosed when fever and other abnormalities of vital signs are present along with abnormalities of one or more organ systems that are not the site of infection and trauma (but with an identifiable locus of infection), and is associated with a range of 30% to 50% mortality. In the United States, one of the most frequent and serious problems confronting clinicians is the management of a serious infection and the systemic response to the infection, such as sepsis. Endotoxins are responsible for initiation of septic shock, which increases the number of fatalities in Gram-negative bacteremia among patients. Inflammation is meant to preserve health, but it is a double-edged sword because of its potential to cause irreversible tissue damage. Like other physiologic systems, the inflammatory response must be turned on and off as required. At present, our knowledge of the pathophysiologic changes at the initiation of the inflammatory process is in infancy, and the mechanism(s) of these signals are relatively less understood. Sepsis gives rise to pronounced metabolic alterations in various organs and tissues, particularly with increased muscle protein breakdown and stimulated hepatic protein synthesis. Although it leads to muscle wasting and increased nitrogen secretion, protein metabolic alteration also serves as an adaptive response in early sepsis as it provides amino acids for hepatic acute phase protein synthesis and gluconeogenesis. Calcium plays vital roles in the intracellular regulation of a variety of cellular responses (for example, contraction, secretion, cell-cell communication, cell proliferation) under physiologic conditions in various cell-types. Alterations in intracellular Ca2+ regulation leading to elevated cytosolic Ca2+ concentration could not only interfere with the cellular responses but also activate lytic enzymes such as proteinases and phospholipases. The objective of this article is to discuss the experimental findings that indicates relationship between alterations in cellular signaling and protein metabolic derangements in non-immune cells (skeletal muscle or liver) during sepsis and inflammation.

Animals↗
PubMed1994

Measurement of gap junctional communication by fluorescence activated cell sorting.

Cell-to-cell communication via gap junctions has played a fundamental role in the orderly development of multicellular organisms. Current methods for measuring this function apply mostly to homotypic cell populations. The newly introduced Fluorescence Activated Cell Sorting (FACS) method, albeit with some limitations, is simple, reliable, and quantitative in measuring the dye transfer via gap junctions in both homotypic and heterotypic cell populations. In the homotypic setting, the result in dye transfer from the FACS method is comparable to the scrape-loading and microinjection methods. Using this FACS method, we observed a decline of cell-to-cell communication in transformed and cancer cells. We also observed a differential degree of communication between two heterotypic cell populations depending on the direction of dye transfer.

Animals↗
PubMed2000

Dephosphorylation agents depress gap junctional communication between rat cardiac cells without modifying the Connexin43 phosphorylation degree.

The functional state of gap junctional channels and the phosphorylation status of Connexine43 (Cx43), the major gap junctional protein in rat heart, were evaluated in primary cultures of neonatal rat cardiomyocytes. H7, able to inhibit a range of serine/threonine protein kinases, progressively reduced gap junctional conductance to approximately 13% of its initial value within 10 min except when protein phosphatase inhibitors were also present. The dephosphorylating agent 2,3-Butanedione monoxime (BDM) produced both a quick and reversible interruption of cell-to-cell communication as well as a parallel slow inhibition of junctional currents. The introduction of a non-hydrolysable ATP analogue (ATPgammaS) in the cytosol delayed the second component, suggesting that it was the consequence of protein dephosphorylation. Western blot analysis reveals 2 forms of Cx43 with different electrophoretic mobilities which correspond to its known phosphorylated and dephosphorylated forms. After exposure of the cells to H7 (1 mmol/l, 1h) or BDM (15 mmol/l, 15 min), no modification in the level of Cx43 phosphorylation was observed. The lack of direct correlation between the inhibition of cell-to-cell communication and changes in the phosphorylation status of Cx43 suggest that the functional state of junctional channels might rather be determined by regulatory proteins associated to Cx43.

Animals↗
PubMed1993

Connexin-43-type gap junctions mediate communication between bone marrow stromal cells.

Several morphologic studies have suggested that gap junctions exist between bone marrow stromal cells. This possibility was examined by analysis of stromal cells present in the adherent layer of primary long-term lymphoid bone marrow cultures and in additional studies using a stromal cell line. Results showing that the fluorescent dye lucifer yellow, when microinjected into a single stromal cell, transferred between most other contacting stroma and that stromal cells were electronically coupled provided support that cell-cell communication occurs between these microenvironmental elements. Additional studies showed that transcripts for connexin (Cx) 43, but not for Cx26 or Cx32, were present in a stromal cell line. To examine the potential for regulated cell-cell communication between the stroma, cells were treated with interleukin-1 (IL-1), a cytokine known to affect stromal cell function, and the effects on dye transfer were examined. IL-1 treatment resulted in a reversible decrease in the ability of dye to transfer between stromal cells in contact. Taken together, these studies show that gap junctions exist between stromal cells and that their permeability can be regulated. However, gap junction-mediated cell-cell communication could not be shown between the stroma and developing lymphoid cells.

Animals↗
PubMed2004

Between the sheets: inter-cell-layer communication in plant development.

The cells of plant meristems and embryos are arranged in an organized, and sometimes extremely beautiful, layered pattern. This pattern is maintained by the controlled orientation of cell divisions within layers. However, despite this layered structure, cell behaviour during plant development is not lineage dependent, and does not occur in a mosaic fashion. Many studies, both classical and recent, have shown that plant cell identity can be re-specified according to position, allowing plants to show remarkable developmental plasticity. However, the layered structure of meristems and the implications of this during plant development, remain subjects of some speculation. Of particular interest is the question of how cell layers communicate, and how communication between cell layers could allow coordinated developmental processes to take place. Recent research has uncovered several examples both of the molecular mechanisms by which cell layers can communicate, and of how this communication can infringe on developmental processes. A range of examples is used to illustrate the diversity of mechanisms potentially implicated in cell-layer communication during plant development.

Cell Communication↗
PubMed1984

Monoclonal antibody ECCD-1 inhibits intercellular communication in teratocarcinoma PCC3 cells.

The monoclonal antibody ECCD-1 recognizing a certain class of cell surface proteins inhibits the Ca2+-dependent cell-to-cell adhesion in teratocarcinoma stem cells. In this paper, we studied the effect of ECCD-1 on cell-to-cell communication in PCC3 cells by measuring the transfer of lucifer yellow between cells. To this aim, PCC3 cells were cultured in the presence of ECCD-1 for various periods, and then the fluorescent dye was injected into a cell located in the center of cell colonies, followed by counting number of cells to which the dye was transferred. The results showed that ECCD-1 inhibits the dye transfer between cells, suggesting that the Ca2+-dependent cell-to-cell adhesion system (CDS) is essential for the functions of gap junction.

Animals↗
PubMed1996

Complexity, communication between cells, and identifying the functional components of living systems: some observations.

The concept of 'complexity' has become very important in theoretical biology. It is a many faceted concept and too new and ill defined to have a universally accepted meaning. This review examines the development of this concept from the point of view of its usefulness as a criteria for the study of living systems to see what it has to offer as a new approach. In particular, one definition of complexity has been put forth which has the necessary precision and rigor to be considered as a useful categorization of systems, especially as it pertains to those we call 'living'. This definition, due to Robert Rosen, has been developed in a number of works and involves some deep new concepts about the way we view systems. In particular, it focuses on the way we view the world and actually practice science through the use of the modelling relation. This mathematical object models the process by which we assign meaning to the world we perceive. By using the modelling relation, it is possible to identify the subjective nature of our practices and deal with this issue explicitly. By so doing, it becomes clear that our notion of complexity and especially its most popular manifestations, is in large part a product of the historical processes which lead to the present state of scientific epistemology. In particular, it is a reaction to the reductionist/mechanistic view of nature which can be termed the 'Newtonian Paradigm'. This approach to epistemology has dominated for so that its use as a model has become implicit in most of what we do in and out of science. The alternative to this approach is examined and related to the special definition of complexity given by Rosen. Some historical examples are used to emphasize the dependence of our view of what is complex in a popular sense on the ever changing state of our knowledge. The role of some popular concepts such as chaotic dynamics are examined in this context. The fields of artificial life and related areas are also viewed from the perspective of this rigorous view of complexity and found lacking. The notion that in some way life exists 'at the edge of chaos' is examined from the perspective of the second law of thermodynamics given by Schneider and Kay. Finally, the casual elements in complex systems are explored in relation to complexity. Rosen has shown that a clear difference in causal relations exists between complex and simple systems and that this difference leads to a uniquely useful definition of what we mean by 'living'. Rosen makes it very clear that the class of systems which are complex is a much larger class than those which we call living. For that reason, the focus of this review will be on complexity as a stepping stone towards the deeper question of what makes a system alive.

Animals↗