Search results for "JUNCTIONS"

Bioelectrical model of head-tail patterning based on cell ion channels and intercellular gap junctions

2020

Robust control of anterior-posterior axial patterning during regeneration is mediated by bioelectric signaling. However, a number of systems-level properties of bioelectrochemical circuits, including stochastic outcomes such as seen in permanently de-stabilized "cryptic" flatworms, are not completely understood. We present a bioelectrical model for head-tail patterning that combines single-cell characteristics such as membrane ion channels with multicellular community effects via voltage-gated gap junctions. It complements the biochemically-focused models by describing the effects of intercellular electrochemical coupling, cutting plane, and gap junction blocking of the multicellular ensemb…

Shortstop Recruits EB1/APC1 and Promotes Microtubule Assembly at the Muscle-Tendon Junction

2003

Abstract Background: Shot (previously named Kakapo), is a Drosophila Plakin family member containing both Actin binding and microtubule binding domains. In Drosophila , it is required for a wide range of processes, including axon extension, dendrite formation, axonal terminal arborization at the neuromuscular junction, tendon cell development, and adhesion of wing epithelium. Results: To address how Shot exerts its activity at the molecular level, we investigated the molecular interactions of Shot with candidate proteins in mature larval tendon cells. We show that Shot colocalizes with EB1/APC1 and with a compact microtubule array extending between the muscle-tendon junction and the cuticle…

Complexus adhaerentes, a new group of desmoplakin-containing junctions in endothelial cells: II. Different types of lymphatic vessels.

1994

Abstract In diverse mammalian species, including (man, cow and rat) the very flat endothelial cells of lymphatic vessels of various organs, including the retothelial meshwork of sinus of lymph nodes, are connected by zonula -like plaque-bearing junctions which differ from the similarly structured junctions of blood vessel endothelia by the presence of desmoplakin or an as yet unknown but closely related plaque protein. These extended junctions, which also contain plakoglobin but none of the presently known desmogleins and desmocollins, are therefore different from the spot-like desmosomes ( maculae adhaerentes ) present in epithelia, myocardium and dendritic reticulum cells of lymphatic fol…

Mechanisms of tumor invasion: evidence from in vivo observations.

1985

The major mechanisms of tumor invasion in vivo are discussed in the present review. A special emphasis is placed on tumor dedifferentiation which has proved to be of paramount importance for the invasion process. Based on in vivo observations obtained from various human and animal tumors a concept for the mechanism of tumor invasion is proposed which mainly comprises the following basic events: the first and essential step in tumor invasion is the tumor dedifferentiation and dissociation at the invasion front. This apparently temporary and reversible process mobilizes the tumor cells out of the main tumor bulk and enables them to invade the host tissue by active locomotion. This mechanism i…

Nitric oxide--a versatile key player in cochlear function and hearing disorders.

2012

Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent…

Thin-Film Heterojunction by Carbon Nanotube Derivatives with Enhanced Solubility and Optical Properties

2012

THIN-FILM HETROJUNCTION BY CARBON NANOTUBE DERIVATIVES WITH ENHANCED SOLUBILITY AND OPTICAL PROPERTIES

2012

The combination of single-walled carbon nanotubes (SWNTs), characterized by high electron mobility, with p-type semiconducting polymers could lead to an overall improvement in the exciton dissociation and carrier extraction efficiencies in practical devices.1However, one of the main concern in the use of SWNTs, relates to the their scarce solubility. Chemical modification has been widely employed to increase the solubility of SWNTs, but usual reaction conditions limit such syntheses to a small scale with low productivity. Here, we employ SWNTs which have been functionalized with aromatic and heteroaromatic moieties via 1,3-dipolar cycloaddition and through diazotization reaction under batch…

All-trans retinoic acid restores gap junctional intercellular communication between oral cancer cells with upregulation of Cx32 and Cx43 expressions …

2012

Objective: All-trans retinoic acid (ATRA) has been demonstrated to inhibit tumor growth by restoration of gap junctional intercellular communication (GJIC) via upregulation of connexin (Cx) expression in some solid tumors. However, the relationship between ATRA and GJIC remains unclear in oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the effect of ATRA on the GJIC function of OSCC. Study design: We measured the effects of ATRA on the viability and cell cycle distribution of SCC9 and Tca8113 OSCC cells. The GJIC function was observed using the scrape-loading dye transfer technique, and the mRNA and protein levels of Cx32 and Cx43 were detected by qRT-PCR, West…

Studying the Neurovascular Unit: An Improved Blood–Brain Barrier Model

2009

The blood–brain barrier (BBB) closely interacts with the neuronal parenchyma in vivo. To replicate this interdependence in vitro, we established a murine coculture model composed of brain endothelial cell (BEC) monolayers with cortical organotypic slice cultures. The morphology of cell types, expression of tight junctions, formation of reactive oxygen species, caspase-3 activity in BECs, and alterations of electrical resistance under physiologic and pathophysiological conditions were investigated. This new BBB model allows the application of techniques such as laser scanning confocal microscopy, immunohistochemistry, fluorescent live cell imaging, and electrical cell substrate impedance se…

L-asparaginase inhibits invasive and angiogenic activity and induces autophagy in ovarian cancer

2012

Recent work identified L-asparaginase (L-ASP) as a putative therapeutic target for ovarian cancer. We suggest that L-ASP, a dysregulator of glycosylation, would interrupt the local microenvironment, affecting the ovarian cancer cell-endothelial cell interaction and thus angiogenesis without cytotoxic effects. Ovarian cancer cell lines and human microvascular endothelial cells (HMVEC) were exposed to L-ASP at physiologically attainable concentrations and subjected to analyses of endothelial tube formation, invasion, adhesion and the assessment of sialylated proteins involved in matrix-associated and heterotypic cell adhesion. Marked reduction in HMVEC tube formation in vitro, HMVEC and ovari…