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  • Cell adhesive peptide screening of the mouse laminin α1 chain G domain. 20727343

    Cell adhesive peptides have been widely applied for therapeutic drugs, drug delivery systems, and biomaterials. Previously, we identified various cell adhesive sequences in the G domains of four laminin α chains (α2-α5) by the systematic soluble peptide screening. We also identified five cell-binding sequences in the laminin α1 chain G domain using synthetic peptide-polystyrene beads. Here, we re-screened cell adhesive peptides in the laminin α1 chain G domain by the systematic soluble peptides screening. The 110 soluble peptides were evaluated for their cell adhesive activities using human fibrosarcoma HT1080 cells and human dermal fibroblasts. Fourteen peptides were newly identified as a cell adhesive. Additionally, four peptides (AG22: SSFHFDGSGYAM, AG42: TFDLLRNSYGVRK, AG76: HQNQMDYATLQLQ, AG86: LGGLPSHYRARNI) promoted integrin-mediated cell adhesion. Further, neurite outgrowth activity with rat pheochromocytoma PC12 cells was evaluated and two peptides (AG20: SIGLWNYIEREGK, AG26: SPNGLLFYLASNG) were newly identified for neurite outgrowth activity. These results suggested that the systematic soluble peptides screening approach is an accurate and powerful strategy for finding biologically active sequences. The active sequences newly identified here could be involved in the biological functions of this domain. The active peptides are useful for evaluating molecular mechanisms of laminin-receptor interactions and for developing cell adhesive biomaterials.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AG100
    Nombre del producto:
    Human IgG Fc Control Protein, recombinant protein

  • Drosophila PIWI associates with chromatin and interacts directly with HP1a. 17875665

    The interface between cellular systems involving small noncoding RNAs and epigenetic change remains largely unexplored in metazoans. RNA-induced silencing systems have the potential to target particular regions of the genome for epigenetic change by locating specific sequences and recruiting chromatin modifiers. Noting that several genes encoding RNA silencing components have been implicated in epigenetic regulation in Drosophila, we sought a direct link between the RNA silencing system and heterochromatin components. Here we show that PIWI, an ARGONAUTE/PIWI protein family member that binds to Piwi-interacting RNAs (piRNAs), strongly and specifically interacts with heterochromatin protein 1a (HP1a), a central player in heterochromatic gene silencing. The HP1a dimer binds a PxVxL-type motif in the N-terminal domain of PIWI. This motif is required in fruit flies for normal silencing of transgenes embedded in heterochromatin. We also demonstrate that PIWI, like HP1a, is itself a chromatin-associated protein whose distribution in polytene chromosomes overlaps with HP1a and appears to be RNA dependent. These findings implicate a direct interaction between the PIWI-mediated small RNA mechanism and heterochromatin-forming pathways in determining the epigenetic state of the fly genome.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-441
    Nombre del producto:
    Anti-dimethyl-Histone H3 (Lys9) Antibody

  • Neuregulin-1 at synapses on phrenic motoneurons. 20878784

    The neuregulin (NRG) family of trophic factors is present in the central and peripheral nervous systems and participates in the survival, proliferation, and differentiation of many different cell types, including motoneurons. NRG1 was first characterized by its role in the formation of the neuromuscular junction, and recently it was shown to play a crucial role in modulating glutamatergic and cholinergic transmission in the central nervous system of adult rats. However, little is known about NRG1's role in adult motor systems. Motoneurons receive dense glutamatergic and cholinergic input. We hypothesized that NRG1 is present at synapses on phrenic motoneurons. Confocal microscopy and 3D reconstruction techniques were used to determine the distribution of NRG1 and its colocalization with these different neurotransmitter systems. We found that NRG1 puncta are present around retrogradely labeled motoneurons and are distributed predominantly at motoneuron somata and primary dendrites. NRG1 is present exclusively at synaptic sites (identified using the presynaptic marker synaptophysin), making up ∼30% of all synapses at phrenic motoneurons. Overall, NRG1 immunoreactivity is found predominantly at cholinergic synapses (75% ± 14% colocalize with the vesicular acetylcholine transporter; VAChT). Nearly all (99% ± 1%) VAChT-immunoreactive synapses expressed NRG1. NRG1 also is present at a subset of glutamatergic synapses expressing the vesicular glutamate transporter (VGLUT) type 2 (∼6%) but not those expressing VGLUT type 1. Overall, 26% ± 6% of NRG1 synapses are VGLUT2 immunoreactive. These findings provide the first evidence suggesting that NRG1 may modulate synaptic activity in adult motor systems.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB5504
    Nombre del producto:
    Anti-Vesicular Glutamate Transporter 2 Antibody

  • Efferent control of the electrical and mechanical properties of hair cells in the bullfrog's sacculus. 21048944

    Hair cells in the auditory, vestibular, and lateral-line systems respond to mechanical stimulation and transmit information to afferent nerve fibers. The sensitivity of mechanoelectrical transduction is modulated by the efferent pathway, whose activity usually reduces the responsiveness of hair cells. The basis of this effect remains unknown.We employed immunocytological, electrophysiological, and micromechanical approaches to characterize the anatomy of efferent innervation and the effect of efferent activity on the electrical and mechanical properties of hair cells in the bullfrog's sacculus. We found that efferent fibers form extensive synaptic terminals on all macular and extramacular hair cells. Macular hair cells expressing the Ca(2+)-buffering protein calretinin contain half as many synaptic ribbons and are innervated by twice as many efferent terminals as calretinin-negative hair cells. Efferent activity elicits inhibitory postsynaptic potentials in hair cells and thus inhibits their electrical resonance. In hair cells that exhibit spiking activity, efferent stimulation suppresses the generation of action potentials. Finally, efferent activity triggers a displacement of the hair bundle's resting position.The hair cells of the bullfrog's sacculus receive a rich efferent innervation with the heaviest projection to calretinin-containing cells. Stimulation of efferent axons desensitizes the hair cells and suppresses their spiking activity. Although efferent activation influences mechanoelectrical transduction, the mechanical effects on hair bundles are inconsistent.
    Tipo de documento:
    Referencia
    Referencia del producto:
    AB1550

  • The pre- and post-somatic segments of the human type I spiral ganglion neurons--structural and functional considerations related to cochlear implantation. 25316409

    Human auditory nerve afferents consist of two separate systems; one is represented by the large type I cells innervating the inner hair cells and the other one by the small type II cells innervating the outer hair cells. Type I spiral ganglion neurons (SGNs) constitute 96% of the afferent nerve population and, in contrast to other mammals, their soma and pre- and post-somatic segments are unmyelinated. Type II nerve soma and fibers are unmyelinated. Histopathology and clinical experience imply that human SGNs can persist electrically excitable without dendrites, thus lacking connection to the organ of Corti. The biological background to this phenomenon remains elusive. We analyzed the pre- and post-somatic segments of the type I human SGNs using immunohistochemistry and transmission electron microscopy (TEM) in normal and pathological conditions. These segments were found surrounded by non-myelinated Schwann cells (NMSCs) showing strong intracellular expression of laminin-β2/collagen IV. These cells also bordered the perikaryal entry zone and disclosed surface rugosities outlined by a folded basement membrane (BM) expressing laminin-β2 and collagen IV. It is presumed that human large SGNs are demarcated by three cell categories: (a) myelinated Schwann cells, (b) NMSCs and (c) satellite glial cells (SGCs). Their BMs express laminin-β2/collagen IV and reaches the BM of the sensory epithelium at the habenula perforata. We speculate that the NMSCs protect SGNs from further degeneration following dendrite loss. It may give further explanation why SGNs can persist as electrically excitable monopolar cells even after long-time deafness, a blessing for the deaf treated with cochlear implantation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Inhibition of Jak1-dependent signal transduction in airway epithelial cells infected with adenovirus. 17641294

    Adenoviral evolution has generated mechanisms to resist host cell defense systems, but the biochemical basis for evasion of multiple antiviral pathways in the airway by adenoviruses is incompletely understood. We hypothesized that adenoviruses modulate airway epithelial responses to type I interferons by altering the levels and activation of specific Janus family kinase-signal transducer and activator of transcription (JAK-STAT) signaling components. In this study, specific effects of adenovirus type 5 (AdV) on selected JAK-STAT signal transduction pathways were identified in human tracheobronchial epithelial cells, with focus on type I interferon-dependent signaling and gene expression. We found that wild-type AdV infection inhibited IFN-alpha-induced expression of antiviral proteins in epithelial cells by blocking phosphorylation of the Stat1 and Stat2 transcription factors that are required for activation of type I interferon-dependent genes. These effects correlated with AdV-induced down-regulation of expression of the receptor-associated tyrosine kinase Jak1 through a decrease in Jak1 mRNA levels. Phosphorylation of Stat3 in response to IL-6 and oncostatin M was also lost in AdV-infected cells, indicating loss of epithelial cell responses to other cytokines that depend on Jak1. In contrast, IL-4- and IL-13-dependent phosphorylation of Stat6 was not affected during AdV infection, indicating that the virus modulates specific signaling pathways, as these Stat6-activating pathways can function independent of Jak1. Taken together, the results indicate that AdV down-regulates host epithelial cell Jak1 to assure inhibition of the antiviral effects of multiple mediators to subvert airway defense responses and establish a productive infection.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Histamine promotes osteoclastogenesis through the differential expression of histamine receptors on osteoclasts and osteoblasts. 19264900

    In addition to the numerous roles of histamine in both the immune and nervous systems, previous studies have suggested that this bioamine might also be involved in bone metabolism. Following our observations of impaired bone resorption in ovariectomized rats after histamine receptor antagonist treatment, we focused in this study on osteoclasts and osteoclast precursors. We looked for a direct action of histamine on these cells using both in vivo and in vitro approaches. In vivo, we triggered a remodeling sequence in rat mandibular bone and treated the animals with either histamine or histamine receptor antagonists. Histamine was shown to increase the number of osteoclasts and osteoclast precursors whereas antagonists of histamine receptor-1 and -2 decreased both osteoclast recruitment and resorption. In vitro, spleen cells from histamine-deficient mice were treated with receptor activator for nuclear factor kappa B ligand and macrophage colony stimulating factor, giving rise to both reduced numbers of osteoclasts and decreased resorption on dentin slices. Histamine enhanced resorption in these cultures in a dose-dependent manner. In addition, we identified osteoclast precursors as a source of histamine. In contrast, histamine increased the receptor activator for nuclear factor kappa B ligand/osteoprotegerin ratio in primary osteoblasts that did not secrete histamine. We observed a differential expression of histamine receptor-1 and -2 mRNAs in both primary osteoclasts and osteoblasts, confirming their functional roles with selective antagonists. Thus, histamine acts directly on osteoclasts, osteoclast precursors, and osteoblasts, promoting osteoclastogenesis through autocrine/paracrine mechanisms.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1435
    Nombre del producto:
    Anti-Macrophages/Monocytes Antibody, clone ED-1

  • A reliable method for organ culture of neonatal mouse retina with long-term survival. 10065994

    Organ culture systems of the central nervous system have proven to be useful tools for the study of development, differentiation, and degeneration. Some studies have been limited by the inability to maintain the cultures over an extended period. Here we describe an organ culture technique for the mouse retina. This method uses commercially available supplies and reproducible procedures to maintain healthy retinas with normal architecture for 4 weeks in vitro. The system is amenable to quantitative analysis. It can be used with both normal and retinal degeneration (rd) retinas to study of the role of various factors in photoreceptor degeneration in retinal cell fate determination and development.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Mitogen-activated protein kinases: a new therapeutic target in cardiac pathology. 12841640

    Eukaryotic cells respond to different external stimuli by activation of mechanisms of cell signaling. One of the major systems participating in the transduction of signal from the cell membrane to nuclear and other intracellular targets is the highly conserved mitogen-activated protein kinase (MAPK) superfamily. The members of MAPK family are involved in the regulation of a large variety of cellular processes such as cell growth, differentiation, development, cell cycle, death and survival. Several MAPK subfamilies, each with apparently unique signaling pathway, have been identified in the mammalian myocardium. These cascades differ in their upstream activation sequence and in downstream substrate specifity. Each pathway follows the same conserved three-kinase module consisting of MAPK, MAPK kinase (MAPKK, MKK or MEK), and MAPK kinase kinase (MAPKKK, MEKK). The major groups of MAPKs found in cardiac tissue include the extracellular signal-regulated kinases (ERKs), the stress-activated/c-Jun NH2-terminal kinases (SAPK/JNKs), p38-MAPK, and ERK5/big MAPK 1 (BMK1). The ERKs are strongly activated by mitogenic and growth factors and by physical stress, whereas SAPK/JNKs and p38-MAPK can be activated by various cell stresses, such as hyperosmotic shock, metabolic stress or protein synthesis inhibitors, UV radiation, heat shock, cytokines, and ischemia. Activation of MAPKs family plays a key role in the pathogenesis of various processes in the heart, e.g. myocardial hypertrophy and its transition to heart failure, in ischemic and reperfusion injury, as well in the cardioprotection conferred by ischemia- or pharmacologically-induced preconditioning. The following approaches are currently utilized to elucidate the role of MAPKs in the myocardium: (i) studies of the effects of myocardial processes on the activity of these kinases; (ii) pharmacological modulations of MAPKs activity and evaluation of their impact on the (patho)physiological processes in the heart; (iii) gene targeting or expression of constitutively active and dominant-negative forms of enzymes (adenovirus-mediated gene transfer). This review is focused on the regulatory role of MAPKs in the myocardium, with particular regard to their involvement in pathophysiological processes, such as myocardial hypertrophy and heart failure, ischemia/reperfusion injury, as well as in the mechanisms of cardioprotection. In addition, it summarizes current information on pharmacological modulations of MAPKs activity and their impact on the cardiac response to pathophysiological processes.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-691

  • RNA interference of Marlin-1/Jakmip1 results in abnormal morphogenesis and migration of cortical pyramidal neurons. 22828129

    The formation of the nervous systems requires processes that coordinate proliferation, differentiation and migration of neuronal cells, which extend axons, generate dendritic branching and establish synaptic connections during development. The structural organization and dynamic remodeling of the cytoskeleton and its association to the secretory pathway are critical determinants of cell morphogenesis and migration. Marlin-1 (Jakmip1) is a microtubule-associated protein predominantly expressed in neurons and lymphoid cells. Marlin-1 participates in polarized secretion in lymphocytes, but its functional association with the neuronal cytoskeleton and its contribution to brain development have not been explored. Combining in vitro and in vivo approaches we show that Marlin-1 contributes to the establishment of neuronal morphology. Marlin-1 associates to the cytoskeleton in neurites, is required for the maintenance of an intact Golgi apparatus and its depletion produces the down-regulation of kinesin-1, a plus-end directed molecular motor with a central function in morphogenesis and migration. RNA interference of Marlin-1 in vivo results in abnormal migration of newborn pyramidal neurons during the formation of the cortex. Our results support the involvement of Marlin-1 in the acquisition of the complex architecture and migration of pyramidal neurons, two fundamental processes for the laminar layering of the cortex.
    Tipo de documento:
    Referencia
    Referencia del producto:
    MAB1614
    Nombre del producto:
    Anti-Kinesin Antibody, heavy chain, a.a.420-445, clone H2