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Gap junction

Robert Galinsky, Joanne O Davidson, Justin M Dean, Colin R Green, Laura Bennet, Alistair J Gunn
Perinatal encephalopathy remains a major cause of disability, such as cerebral palsy. Therapeutic hypothermia is now well established to partially reduce risk of disability in late preterm/term infants. However, new and complementary therapeutic targets are needed to further improve outcomes. There is increasing evidence that glia play a key role in neural damage after hypoxia-ischemia and infection/inflammation. In this review, we discuss the role of astrocytic gap junction (connexin) hemichannels in the spread of neural injury after hypoxia-ischemia and/or infection/inflammation...
February 2018: Neural Regeneration Research
Chenju Yi, Jérémy Theillon, Annette Koulakoff, Hugues Berry, Christian Giaume
Intercellular communication through gap junction channels plays a key role in cellular homeostasis and in synchronizing physiological functions, a feature that is modified in number of pathological situations. In the brain, astrocytes are the cell population that expresses the highest amount of gap junction proteins, named connexins. Several techniques have been used to assess the level of gap junctional communication in astrocytes, but so far they remain very difficult to apply in adult brain tissue. Here, using specific loading of astrocytes with sulforhodamine 101, we adapted the gap-FRAP (Fluorescence Recovery After Photobleaching) to acute hippocampal slices from 9 month-old adult mice...
March 15, 2018: Journal of Neuroscience Methods
Robert D Johnson, Patrizia Camelliti
The heart is a complex organ composed of multiple cell types, including cardiomyocytes and different non-myocyte populations, all working closely together to determine the hearts properties and maintain normal cardiac function. Connexins are abundantly expressed proteins that form plasma membrane hemichannels and gap junctions between cells. Gap junctions are intracellular channels that allow for communication between cells, and in the heart they play a crucial role in cardiac conduction by coupling adjacent cardiomyocytes...
March 15, 2018: International Journal of Molecular Sciences
Jinho Park, Jae Hyeong Lee, Gil-Ho Lee, Yositake Takane, Ken-Ichiro Imura, Takashi Taniguchi, Kenji Watanabe, Hu-Jong Lee
We report on short ballistic (SB) Josephson coupling in junctions embedded in a planar heterostructure of graphene. Ballistic Josephson coupling is confirmed by the Fabry-Perot-type interference of the junction critical current I_{c}. The product of I_{c} and the normal-state junction resistance R_{N}, normalized by the zero-temperature gap energy Δ_{0} of the superconducting electrodes, turns out to be exceptionally large close to 2, an indication of strong Josephson coupling in the SB junction limit. However, I_{c} shows a temperature dependence that is inconsistent with the conventional short-junction-like behavior based on the standard Kulik-Omel'yanchuk prediction...
February 16, 2018: Physical Review Letters
Zhikai Zhao, Ran Liu, Dirk Mayer, Maristella Coppola, Lu Sun, Youngsang Kim, Chuankui Wang, Lifa Ni, Xing Chen, Maoning Wang, Zongliang Li, Takhee Lee, Dong Xiang
A straightforward method to generate both atomic-scale sharp and atomic-scale planar electrodes is reported. The atomic-scale sharp electrodes are generated by precisely stretching a suspended nanowire, while the atomic-scale planar electrodes are obtained via mechanically controllable interelectrodes compression followed by a thermal-driven atom migration process. Notably, the gap size between the electrodes can be precisely controlled at subangstrom accuracy with this method. These two types of electrodes are subsequently employed to investigate the properties of single molecular junctions...
March 15, 2018: Small
Jihwan Myung, Christoph Schmal, Sungho Hong, Yoshiaki Tsukizawa, Pia Rose, Yong Zhang, Michael J Holtzman, Erik De Schutter, Hanspeter Herzel, Grigory Bordyugov, Toru Takumi
Mammalian circadian clocks have a hierarchical organization, governed by the suprachiasmatic nucleus (SCN) in the hypothalamus. The brain itself contains multiple loci that maintain autonomous circadian rhythmicity, but the contribution of the non-SCN clocks to this hierarchy remains unclear. We examine circadian oscillations of clock gene expression in various brain loci and discovered that in mouse, robust, higher amplitude, relatively faster oscillations occur in the choroid plexus (CP) compared to the SCN...
March 14, 2018: Nature Communications
Muhammad Iqbal, Muhammad Rehan, Keum-Shik Hong
This paper exploits the dynamical modeling, behavior analysis, and synchronization of a network of four different FitzHugh-Nagumo (FHN) neurons with unknown parameters linked in a ring configuration under direction-dependent coupling. The main purpose is to investigate a robust adaptive control law for the synchronization of uncertain and perturbed neurons, communicating in a medium of bidirectional coupling. The neurons are assumed to be different and interconnected in a ring structure. The strength of the gap junctions is taken to be different for each link in the network, owing to the inter-neuronal coupling medium properties...
2018: Frontiers in Neurorobotics
Y Wang, W Guo, H Xu, X Zhu, T Yu, Z Jiang, Q Jiang, X Gang
The study aimed to identify the pivotal genes and pathways involved in prostate cancer metastasis. Using the expression profile dataset GSE7930, downloaded from the Gene Expression Omnibus (GEO) database, differentially expressed genes (DEGs) between primary and highly metastatic prostate cell samples were screened, followed by functional analysis and tumor associated genes (TAG) screening. Protein-protein interaction (PPI) network of DEGs was constructed and module analysis was performed. The expression of DEGs and pathway related genes were evaluated by PCR analysis and the migra- tion ability of prostate tumor cells was observed after FABP4-siRNA blocking...
2018: Neoplasma
Sara Crespo Yanguas, Tereza C da Silva, Isabel V A Pereira, Joost Willebrords, Michaël Maes, Marina Sayuri Nogueira, Inar Alves de Castro, Isabelle Leclercq, Guilherme R Romualdo, Luís F Barbisan, Luc Leybaert, Bruno Cogliati, Mathieu Vinken
Although a plethora of signaling pathways are known to drive the activation of hepatic stellate cells in liver fibrosis, the involvement of connexin-based communication in this process remains elusive. Connexin43 expression is enhanced in activated hepatic stellate cells and constitutes the molecular building stone of hemichannels and gap junctions. While gap junctions support intercellular communication, and hence the maintenance of liver homeostasis, hemichannels provide a circuit for extracellular communication and are typically opened by pathological stimuli, such as oxidative stress and inflammation...
March 12, 2018: International Journal of Molecular Sciences
Annalucia Carbone, Roberto Zefferino, Elisa Beccia, Valeria Casavola, Stefano Castellani, Sante Di Gioia, Valentina Giannone, Manuela Seia, Antonella Angiolillo, Carla Colombo, Maria Favia, Massimo Conese
We previously found that human amniotic mesenchymal stem cells (hAMSCs) in coculture with CF immortalised airway epithelial cells (CFBE41o- line, CFBE) on Transwell® filters acquired an epithelial phenotype and led to the expression of a mature and functional CFTR protein. In order to explore the role of gap junction- (GJ-) mediated intercellular communication (GJIC) in this rescue, cocultures (hAMSC : CFBE, 1 : 5 ratio) were studied for the formation of GJIC, before and after silencing connexin 43 (Cx43), a major component of GJs...
2018: Stem Cells International
Ekaterina Khestanova, John Birkbeck, Mengjian Zhu, Yang Cao, Geliang Yu, Davit Ghazaryan, Jun Yin, Helmuth Berger, László Forró, Takashi Taniguchi, Kenji Watanabe, Roman Vladislavovich Gorbachev, Artem Mishchenko, Andre K Geim, Irina V Grigorieva
It is well known that superconductivity in thin films is generally suppressed with decreasing thickness. This suppression is normally governed by either disorder-induced localization of Cooper pairs, weakening of Coulomb screening, or generation and unbinding of vortex-antivortex pairs as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory. Defying general expectations, few-layer NbSe2 - an archetypal example of ultrathin superconductors - has been found to remain superconducting down to monolayer thickness...
March 12, 2018: Nano Letters
Guillaume Pernelle, Wilten Nicola, Claudia Clopath
Cortical oscillations are thought to be involved in many cognitive functions and processes. Several mechanisms have been proposed to regulate oscillations. One prominent but understudied mechanism is gap junction coupling. Gap junctions are ubiquitous in cortex between GABAergic interneurons. Moreover, recent experiments indicate their strength can be modified in an activity-dependent manner, similar to chemical synapses. We hypothesized that activity-dependent gap junction plasticity acts as a mechanism to regulate oscillations in the cortex...
March 12, 2018: PLoS Computational Biology
Gi Soon Park, Van Ben Chu, Byoung Woo Kim, Dong-Wook Kim, Hyung-Suk Oh, Yun Jeong Hwang, Byoung Koun Min
An optimization of band alignment at the p-n junction interface is realized on alcohol-based solution-processed Cu(In,Ga)(S,Se)2 (CIGS) thin film solar cells, achieving a power-conversion-efficiency (PCE) of 14.4%. To obtain a CIGS thin film suitable for interface engineering, a novel "3-step chalcogenization process" is designed for Cu2-xSe-derived grain growth and a double band gap grading structure. Considering S-rich surface of the CIGS thin film, an alternative ternary (Cd,Zn)S buffer layer is adopted to build favorable "spike" type conduction band alignment instead of "cliff" type...
March 12, 2018: ACS Applied Materials & Interfaces
Shirley L Zhang, Zhifeng Yue, Denice M Arnold, Gregory Artiushin, Amita Sehgal
Endogenous circadian rhythms are thought to modulate responses to external factors, but mechanisms that confer time-of-day differences in organismal responses to environmental insults/therapeutic treatments are poorly understood. Using a xenobiotic, we find that permeability of the Drosophila "blood"-brain barrier (BBB) is higher at night. The permeability rhythm is driven by circadian regulation of efflux and depends on a molecular clock in the perineurial glia of the BBB, although efflux transporters are restricted to subperineurial glia (SPG)...
February 27, 2018: Cell
Ipsita Mohanty, Subas Chandra Parija, Sujit Suklabaidya, Satish Rattan
Extracellular pH is an important physiological determinant of vascular tone that is normally maintained within 7.35-7.45. Any change outside this range leads to severe pathological repercussions. We investigated the unknown effects of extracellular acidosis on relaxation in the superior mesenteric artery (SMA) of goat. SMA rings were employed to maintain isometric contractions at extracellular pH (pHo ) 7.4 and 6.8. We analyzed the effect of acidosis (pHo 6.8) compared to physiological pH (pHo 7.4) on three signaling mediators of endothelium-dependent hyperpolarization: nitric oxide (NO), prostaglandin I2 (PGI2 ), and myoendothelial gap junctions (MEGJ)...
March 7, 2018: European Journal of Pharmacology
Eugen Brailoiu, Christine L Barlow, Servio H Ramirez, Mary E Abood, G Cristina Brailoiu
Platelet-activating factor (PAF) is a potent phospholipid mediator that exerts various pathophysiological effects by interacting with a G protein-coupled receptor. PAF has been reported to increase the permeability of the blood-brain barrier (BBB) via incompletely characterized mechanisms. We investigated the effect of PAF on rat brain microvascular endothelial cells (RBMVEC), a critical component of the BBB. PAF produced a dose-dependent increase in cytosolic Ca2+ concentration; the effect was prevented by the PAF receptor antagonist, WEB2086...
March 6, 2018: Neuroscience
Amandine Jullienne, Andrew M Fukuda, Aleksandra Ichkova, Nina Nishiyama, Justine Aussudre, André Obenaus, Jérôme Badaut
Aquaporins (AQPs) facilitate water diffusion through the plasma membrane. Brain aquaporin-4 (AQP4) is present in astrocytes and has critical roles in normal and disease physiology. We previously showed that a 24.9% decrease in AQP4 expression after in vivo silencing resulted in a 45.8% decrease in tissue water mobility as interpreted from magnetic resonance imaging apparent diffusion coefficients (ADC). Similar to previous in vitro studies we show decreased expression of the gap junction protein connexin 43 (Cx43) in vivo after intracortical injection of siAQP4 in the rat...
March 8, 2018: Scientific Reports
Cong-Yuan Xia, Zhen-Zhen Wang, Tohru Yamakuni, Nai-Hong Chen
Major depressive disorder (MDD) is a chronic and debilitating illness that affects over 350 million people worldwide; however, current treatments have failed to cure or prevent the progress of depression. Increasing evidence suggests a crucial role for connexins in MDD. In this review, we have summarised recent accomplishments regarding the role of connexins, gap junctions, and hemichannels in the aetiology of MDD, and discussed the limitations of current research. A blockage of gap junctions or hemichannels induces depressive behaviour...
March 5, 2018: European Neuropsychopharmacology: the Journal of the European College of Neuropsychopharmacology
Kateřina Pěnčíková, Lucie Svržková, Simona Strapáčová, Jiří Neča, Iveta Bartoňková, Zdeněk Dvořák, Martina Hýžďalová, Jakub Pivnička, Lenka Pálková, Hans-Joachim Lehmler, Xueshu Li, Jan Vondráček, Miroslav Machala
The mechanisms contributing to toxic effects of airborne lower-chlorinated PCB congeners (LC-PCBs) remain poorly characterized. We evaluated in vitro toxicities of environmental LC-PCBs found in both indoor and outdoor air (PCB 4, 8, 11, 18, 28 and 31), and selected hydroxylated metabolites of PCB 8, 11 and 18, using reporter gene assays, as well as other functional cellular bioassays. We focused on processes linked with endocrine disruption, tumor promotion and/or regulation of transcription factors controlling metabolism of both endogenous compounds and xenobiotics...
March 5, 2018: Environmental Pollution
Amedeo Bellunato, Sasha D Vrbica, Carlos Sabater, Erik W de Vos, Remko Fermin, Kirsten N Kanneworff, Federica Galli, Jan M Van Ruitenbeek, Grégory F Schneider
The investigation of the transport properties of single molecules by flowing tunnelling currents across extremely narrow gaps is relevant for challenges as diverse as the development of molecular electronics and sequencing of DNA. The achievement of well-defined electrode architectures remains a technical challenge, especially due to the necessity of high precision fabrication processes and the chemical instability of most bulk metals. Here, we illustrate a continuously adjustable tunnelling junction between the edges of two twisted graphene sheets...
March 7, 2018: Nano Letters
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