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601.
Molecular and Cellular Basis of Regeneration and Tissue Repair 总被引:3,自引:0,他引:3
Rossi L Salvetti A Batistoni R Deri P Gremigni V 《Cellular and molecular life sciences : CMLS》2008,65(1):16-23
Planarians possess amazing abilities to regulate tissue homeostasis and regenerate missing body parts. These features reside on the presence of a population of pluripotent/totipotent stem cells, the neoblasts, which are considered as the only planarian cells able to proliferate in the asexual strains. Neoblast distribution has been identified by mapping the cells incorporating bromodeoxyuridine, analyzing mitotic figures and using cell proliferation markers. Recently identified molecular markers specifically label subgroups of neoblasts, revealing thus the heterogeneity of the planarian stem cell population. Therefore, the apparent totipotency of neoblasts probably reflects the composite activities of multiple stem cell types. First steps have been undertaken to understand how neoblasts and differentiated cells communicate with each other to adapt the self-renewal and differentiation rates of neoblasts to the demands of the body. Moreover, the introduction of molecular resource database on planarians now paves the way to renewed strategies to understand planarian regeneration and stem cell-related issues. 相似文献
602.
The potential effects of synthetic unmethylated oligodeoxynucleotides (ODN) containing CpG motifs, mimicking bacterial DNA, has never been evaluated on the immune response in the teleost fish gilthead seabream (Sparus aurata), the most important fish species in Mediterranean aquaculture. First, binding and competition studies have demonstrated that binding is saturated and promiscuous, suggesting the participation of several receptors. Moreover, leucocyte cytotoxic (NCC) activity, production of ROIs (reactive oxygen intermediates), and expression of immune-relevant genes was greatly primed by ODNs. Focusing on the mechanism, the TLR9 gene is widely distributed in seabream tissues and differently regulated in vitro by several stimuli. Moreover, and for the first time in fish, TLR9 mRNA has been detected in lymphocytes as the main cell-source. To conclude, ODNs containing GACGTT, GTCGTT (optimal for mouse and human, respectively) or AACGTT motifs are the most potent inducers of seabream immunity, whilst the involvement of TLR9 is under debate. 相似文献
603.
Leung JY Chapman JA Harris JA Hale D Chung RS West AK Chuah MI 《Cellular and molecular life sciences : CMLS》2008,65(17):2732-2739
Olfactory ensheathing cells (OECs) have been shown previously to express Toll-like receptors and to respond to bacteria by translocating nuclear factor-kappaB from the cytoplasm to the nucleus. In this study, we show that OECs extended significantly more pseudopodia when they were exposed to Escherichia coli than in the absence of bacteria (p=0.019). Co-immunoprecipitation showed that E. coli binding to OECs was mediated by Toll-like receptor 4. Lyso-Tracker, a fluorescent probe that accumulates selectively in lysosomes, and staining for type 1 lysosome-associated membrane proteins demonstrated that endocytosed FITC-conjugated E. coli were translocated to lysosomes. They appeared to be subsequently broken down, as shown by transmission electron microscopy. No obvious adherence to the membrane and less phagocytosis was observed when OECs were incubated with inert fluorescent microspheres. The ability of OECs to endocytose bacteria supports the notion that OECs play an innate immune function by protecting olfactory tissues from bacterial infection. 相似文献
604.
Src-family kinases (SFKs) regulate different granulocyte and monocyte/macrophage responses. Accumulating evidence suggests that members of this family are implicated in signal transduction pathways regulating phagocytic cell migration and recruitment into inflammatory sites. Macrophages with a genetic deficiency of SFKs display marked alterations in cytoskeleton dynamics, polarization and migration. This same phenotype is found in cells with either a lack of SFK substrates and/or interacting proteins such as Pyk2/FAK, c-Cbl and p190RhoGAP. Notably, SFKs and their downstream targets also regulate monocyte recruitment into inflammatory sites. Depending on the type of assay used, neutrophil migration in vitro may be either dependent on or independent of SFKs. Also neutrophil recruitment in in vivo models of inflammation may be regulated differently by SFKs depending on the tissue involved. In this review we will discuss possible mechanisms by which SFKs may regulate phagocytic cell migratory abilities. 相似文献
605.
Arachiche A Badirou I Dachary-Prigent J Garcin I Geldwerth-Feniger D Kerbiriou-Nabias D 《Cellular and molecular life sciences : CMLS》2008,65(23):3861-3871
Rapid Ca2+-dependent phospholipid (PL) reorganization (scrambling) at the plasma membrane is a mechanism common to hematopoietic cells
exposing procoagulant phosphatidylserine (PS). The aim of this research was to determine whether activation of the extracellular
signal-regulated kinase (ERK) pathway was required for PL scrambling, based on a single report analyzing both responses induced
by Ca2+ ionophores in megakaryoblastic HEL cells. Ca2+ ionophore-stimulated ERK phosphorylation was induced in platelets without external Ca2+, whereas exogenous Ca2+ entry was crucial for ERK activation in Jurkat T cells. In both cells, membrane scrambling only occurred following Ca2+ entry and was not blocked by inhibiting ERK phosphorylation. Furthermore, ERK proteins are strongly phosphorylated in transformed
B lymphoblastic cell lines, which do not expose PS in their resting state. Overall, the data demonstrated that ERK activation
and membrane scrambling are independent mechanisms.
A. Arachiche, I. Badirou: These authors contributed equally to this work.
Received 18 June 2008; received after revision 24 September 2008; accepted 1 October 2008 相似文献
606.
Olfactory receptors typically exhibit poor plasma membrane localization and functionality when heterologously expressed in
most cell types. It has therefore proven difficult to effectively study olfactory receptor pharmacology and signaling mechanisms
using traditional cell culture systems. Over the past few years, a variety of distinct proteins have been reported to interact
with olfactory receptors and facilitate olfactory receptor trafficking to the plasma membrane in heterologous cells. Advances
in this area have shed significant light on the fundamental factors governing the cell-specific control of olfactory receptor
trafficking. 相似文献
607.
A. F. Vanin L. M. Bevers A. Slama-Schwok E. E. van Faassen 《Cellular and molecular life sciences : CMLS》2008,65(24):4066-4069
Announcement
Announcement 相似文献608.
Taylor DM Maxwell MM Luthi-Carter R Kazantsev AG 《Cellular and molecular life sciences : CMLS》2008,65(24):4000-4018
Sirtuins comprise a unique class of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases that target multiple protein substrates to execute diverse biological functions. These enzymes are
key regulators of clinically important cellular and organismal processes, including metabolism, cell division and aging. The
desire to understand the important determinants of human health and lifespan has resulted in a firestorm of work on the seven
mammalian sirtuins in less than a decade. The implication of sirtuins in medically important areas such as diabetes, cancer,
cardiovascular dysfunction and neurodegenerative disease has further catapulted them to a prominent status as potential targets
for nutritional and therapeutic development. Here, we present a review of published results on sirtuin biology and its relevance
to human disease.
Received 25 June 2008; received after revision 20 August 2008; accepted 29 August 2008 相似文献
609.
Papaconstantinou ME Gandhi PS Chen Z Bah A Di Cera E 《Cellular and molecular life sciences : CMLS》2008,65(22):3688-3697
Meizothrombin is the physiologically active intermediate generated by a single cleavage of prothrombin at R320 to separate the A and B chains. Recent evidence has suggested that meizothrombin, like thrombin, is a Na(+)-activated enzyme. In this study we present the first X-ray crystal structure of human meizothrombin desF1 solved in the presence of the active site inhibitor PPACK at 2.1 A resolution. The structure reveals a Na(+) binding site whose architecture is practically identical to that of human thrombin. Stopped-flow measurements of Na(+) binding to meizothrombin desF1 document a slow phase of fluorescence change with a k(obs) decreasing hyperbolically with increasing [Na(+)], consistent with the existence of three conformations in equilibrium, E*, E and E:Na(+), as for human thrombin. Evidence that meizothrombin exists in multiple conformations provides valuable new information for studies of the mechanism of prothrombin activation. 相似文献
610.
Molecular mechanisms of phagocytic uptake in mammalian cells 总被引:2,自引:1,他引:1
Groves E Dart AE Covarelli V Caron E 《Cellular and molecular life sciences : CMLS》2008,65(13):1957-1976
Phagocytosis is a highly conserved, complex process that has evolved to counter the constant threat posed by pathogens, effete cells and debris. Classically defined as a mechanism for internalising and destroying particles greater than 0.5 mum in size, it is a receptor-mediated, actin-driven process. The best-studied phagocytic receptors are the opsono-receptors, FcgammaR and CR3. Phagocytic uptake involves actin dynamics including polymerisation, bundling, contraction, severing and depolymerisation of actin filaments. Recent evidence points to the importance of membrane remodelling during phagocytosis, both in terms of changes in lipid composition and delivery of new membrane to the sites of particle binding. Here we review the molecular mechanisms of phagocytic uptake and some of the strategies developed by microbial pathogens to manipulate this process. 相似文献