Search results for "Acellular"
showing 10 items of 1986 documents
Collective Cell Migration in Tissue Building
2015
Collective cell migration (CCM) is an essential process during tissue building and morphogenesis of animal body plans, but it can also occur in pathogenic situations. A detailed study of this cell behaviour in several model systems has allowed to determine that cells move coordinately but interact differently while migrating together, thus defining several categories of collective cell movements. They are regulated by guidance signals that act as chemoattractants and allow directionality of movement and whose levels, together with the action of repulsive molecular cues, influence this movement. Besides, cells in the moving group affect each other through cell–cell interactions but they also…
Streptomyces coelicolor Vesicles: Many Molecules To Be Delivered
2022
ABSTRACT Streptomyces coelicolor is a model organism for the study of Streptomyces, a genus of Gram-positive bacteria that undergoes a complex life cycle and produces a broad repertoire of bioactive metabolites and extracellular enzymes. This study investigated the production and characterization of membrane vesicles (MVs) in liquid cultures of S. coelicolor M145 from a structural and biochemical point of view; this was achieved by combining microscopic, physical and -omics analyses. Two main populations of MVs, with different sizes and cargos, were isolated and purified. S. coelicolor MV cargo was determined to be complex, containing different kinds of proteins and metabolites. In particul…
Alternative splicing products of the tenascin gene distinguish rat liver fat storing cells from arterial smooth muscle cells and skin fibroblasts
1992
Abstract Fat storing-(Ito-)cells (FSC) transform into a myofibroblast-like cell type during liver fibrogenesis. A similar development can be observed in cell culture. At the moment, a definite marker to differentiate transformed FSC from smooth muscle cells (SMC) is not available. We recently found that FSC, SMC and skin fibroblasts (SF) synthesize tenascin, a novel matrix protein. As it is reported that various tissues express different tenascin forms by the mechanism of alternative pre-mRNA splicing, we analyzed the tenascin transcripts in these cell types. Total RNA extracted from cultured FSC, SMC and SF, analyzed by Northern blot hybridization, showed a 7.2 kb transcript in FSC, a 8.7 …
Exosomes as Intercellular Signaling Organelles Involved in Health and Disease: Basic Science and Clinical Applications
2013
Cell to cell communication is essential for the coordination and proper organization of different cell types in multicellular systems. Cells exchange information through a multitude of mechanisms such as secreted growth factors and chemokines, small molecules (peptides, ions, bioactive lipids and nucleotides), cell-cell contact and the secretion of extracellular matrix components. Over the last few years, however, a considerable amount of experimental evidence has demonstrated the occurrence of a sophisticated method of cell communication based on the release of specialized membranous nano-sized vesicles termed exosomes. Exosome biogenesis involves the endosomal compartment, the multivesicu…
Double Face of eHsp70 in Front of Different Situations
2018
The Hsp70 family is one of the best conserved and abundant member of the heat shock proteins (HSP). This family includes several members and in particular one constitutively expressed member (Hsc70) and another one inducibly expressed under several stress conditions (Hsp70). To date, the intracellular functions of Hsp70 are well defined, and increasing evidences establish its roles in the extracellular environment, such as cytoprotection and immunomodulation. Increasing evidences suggest that several cell types are able to release Hsp70 in the extracellular environment, both under physiological and stress conditions. At the same time many release mechanisms have been identified. This chapte…
Cell fate specification in an in vitro model of neural development
1998
We have studied in an in vitro model of neural development the effect of neighboring cells on the fate of single fluorescently labeled precursor cells. In one line of experiments, PCC7-Mz1 embryonal carcinoma cells were transiently transfected with "green fluorescent protein" (GFP) and, following incubation with 0.1 microM all-trans retinoic acid (RA), the number and morphology of derivatives (neuronal or non-neuronal) was determined that form groups of GFP-expressing cells in a surrounding of unlabeled cells. Because single PCC7-Mz1 cells can produce single-lineage and mixed-lineage derivatives, they are individually pluripotent. In another line of experiments, we have analyzed the fate of…
Growth of human cells on a non-woven silk fibroin net: a potential for use in tissue engineering.
2003
We have examined a novel biomaterial consisting of a non-woven fibroin net produced from silk (Bombyx mori) cocoons for its ability to support the growth of human cells. Various human cells of different tissue and cell types (endothelial, epithelial, fibroblast, glial, keratinocyte, osteoblast) were examined for adherence and growth on the nets by confocal laser microscopy after staining of the cells with calcein-AM and by electron microscopy. All the cells readily adhered and spread over the individual fibers of the nets. Most of the cells were able to grow and survive on the nets for at least 7 weeks and growth not only covered the individual fibers of the net but generally bridged the ga…
Regulation of cyclooxygenase-2 expression by cyclic AMP.
2007
Abstract Prostaglandins (PG) regulate many biological processes, among others inflammatory reactions. Cyclooxygenases-1 and -2 (COX-1 and COX-2) catalyse PG synthesis. Since this step is rate limiting, the regulation of COX expression is of critical importance to PG biology. Contrary to COX-1, which is constitutively expressed, COX-2 expression is subject to regulation. For example, COX-2 levels are increased in inflammatory reactions. Many signalling pathways can regulate COX-2 expression, not least those involving receptors for COX products themselves. Analysis of the intracellular signal transducers involved reveals a crucial role for cAMP, albeit as a modulator rather than direct induce…
Biodistribution, Uptake and Effects Caused by Cancer-derived Extracellular Vesicles
2015
Extracellular vesicles (EVs) have recently emerged as important mediators of intercellular communication. They are released in the extracellular space by a variety of normal and cancerous cell types and have been found in all human body fluids. Cancer-derived EVs have been shown to carry lipids, proteins, mRNAs, non-coding and structural RNAs and even extra-chromosomal DNA, which can be taken up by recipient cells and trigger diverse physiological and pathological responses. An increasing body of evidence suggests that cancer-derived EVs mediate paracrine signalling between cancer cells. This leads to the increased invasiveness, proliferation rate and chemoresistance, as well as the acquisi…
Autolysis of Yeasts
2011
Autolysis of yeast cells occurs after they have completed their life cycle and entered the death phase. It is characterized by a loss of cell membrane permeability, alteration of cell wall porosity, hydrolysis of cellular macromolecules by endogenous enzymes, and subsequent leakage of the breakdown products into the extracellular environment. Although a naturally occurring event, autolysis can be induced by exposing yeasts to elevated temperatures (40–60 °C), organic solvents, or detergents. Yeast autolysis occurs in many foods and beverages, where it may affect their sensory quality and commercial acceptability.