TNF-α plus IL-1β Induces Opposite Regulation of Hemichannels and Gap Junctions in Mesangial Cells Through a RhoA/ROCK-dependent Pathway

Connexin 43 (Cx43) is expressed in kidneys and constitutes a feedforward mechanism leading to inflammation in other tissues where they form hemichannels and gap junction channels. However, the possible functional relationship between these membrane channels and their role in damaged renal cells remains unknown. Here, analyses of ethidium uptake and thiobarbituric acid reactive species revealed that TNF-α plus IL-1β increase Cx43 hemichannel activity and oxidative stress in MES-13 cells, a cell line derived from mesangial cells. The latter also was accompanied by a reduction in gap junctional communication, whereas western blotting analysis showed a progressive increase of phosphorylated MYPT (a substrate of RhoA/ROCK) and Cx43 upon TNF-α/IL-1β treatment. Additionally, inhibition of RhoA/ROCK strongly diminished the TNF-α/IL-1β-induced activation of Cx43 hemichannels and reduction in gap junctional coupling. We propose that activation of Cx43 hemichannels and inhibition of cell coupling during pro-inflammatory conditions could contribute to oxidative stress and damage of mesangial cells via the RhoA/ROCK pathway.

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Manipulation of gap junctional communication during compaction of the mouse early embryo

Development ◽

10.1242/dev.91.1.283 ◽

1986 ◽

Vol 91 (1) ◽

pp. 283-296

Author(s):

Harry Goodall

Keyword(s):

Cell Adhesion ◽

Early Embryo ◽

Embryonal Carcinoma Cell ◽

Cell Coupling ◽

Calcium Dependent ◽

Gap Junctional Communication ◽

Embryonal Carcinoma Cell Line ◽

Junctional Communication ◽

Junctional Coupling ◽

Gap Junctional

Three treatments that prevent cell flattening during compaction of the mouse preimplantation embryo were assessed for their effects on the onset of gap junctional communication. Medium low in calcium (LCM) and an antiserum to an embryonal carcinoma cell line (anti-EC; Johnson et al. 1979) both prevented the establishment of coupling between blastomeres of the 8-cell embryo as assessed by transmission of carboxyfluorescein or by ionic coupling. Since neither of these agents prevents the contact-mediated induction of cell polarity that occurs at this stage, it is concluded that the induction of this process is not signalled via gap junctions. A monoclonal antibody (ECCD-1; Yoshida-Noro, Suzuki & Takeichi, 1984), that recognizes more specific components of the calcium-dependent cell adhesion system, failed to prevent the onset of junctional coupling. This suggests that the onset of junctional coupling is not dependent upon extensive cell apposition and that the requirement for extracellular Ca2+ resides at a level other than that of cell adhesion. Moreover, neither LCM nor anti-EC could reverse cell coupling once it had become established despite their complete reversal of cell flattening.

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Connexin 43 mediated gap junctional communication enhances breast tumor cell diapedesis in culture

Breast Cancer Research ◽

10.1186/bcr1042 ◽

2005 ◽

Vol 7 (4) ◽

Cited By ~ 71

Author(s):

Mary-Ann Pollmann ◽

Qing Shao ◽

Dale W Laird ◽

Martin Sandig

Keyword(s):

Tumor Cell ◽

Breast Tumor ◽

Connexin 43 ◽

Breast Tumor Cell ◽

Gap Junctional Communication ◽

Junctional Communication ◽

Gap Junctional

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Syncytial organization of cultured rat mesangial cells

AJP Renal Physiology ◽

10.1152/ajprenal.1991.260.6.f848 ◽

1991 ◽

Vol 260 (6) ◽

pp. F848-F855 ◽

Cited By ~ 5

Author(s):

K. Iijima ◽

L. C. Moore ◽

M. S. Goligorsky

Keyword(s):

Calcium Channels ◽

Mesangial Cells ◽

Calcium Waves ◽

Oxygen Intermediates ◽

Voltage Gated ◽

Fura 2 ◽

Gap Junctional Communication ◽

Voltage Gated Calcium Channels ◽

Junctional Communication ◽

Gap Junctional

To investigate communication competence of cultured rat mesangial cells, Lucifer yellow transfer was studied using microinjection and scrape-loading techniques. Both methods yielded results indicating considerable gap junctional communication between cultured mesangial cells. Gap junctional communication between mesangial cells was upregulated by adenosine 3',5'-cyclic monophosphate (cAMP). Conversely, cell-to-cell communication was attenuated by exposure to the tumor promoter phorbol myristate acetate, the Ca ionophore ionomycin, reduced oxygen intermediates, and cell acidification. Expression of voltage gated calcium channels by mesangial cells was studied microspectrofluorimetrically using fura-2 fluorescence. KCl-induced depolarization, BAY-K 8644, and readdition of calcium to Ca-free depolarizing medium all produced a nifedipine-inhibitable increase in cytosolic calcium concentration. The existence of voltage-gated calcium channels in communication-competent cells suggests the possibility of propagation of depolarizing signals across the syncytium. This was studied by microapplication of KCl to the microenvironment of a single cell and monitoring fura-2 fluorescence in remote cells. This maneuver resulted in propagating calcium waves in communication-competent monolayers; calcium waves could not be evoked in monolayers exposed to an alkanol-type gap junction uncoupler, octanol. It is concluded that cultured rat mesangial cells form a syncytium capable of propagating calcium transients from a single depolarized cell to its coupled neighbors.

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Gap-junctional communication in a communication-defective and in a communication-competent teratocarcinoma cell line

Journal of Cell Science ◽

10.1242/jcs.76.1.85 ◽

1985 ◽

Vol 76 (1) ◽

pp. 85-95

Author(s):

C.W. Lo ◽

D. Fang ◽

M.L. Hooper

Keyword(s):

Cell Line ◽

Coupling Coefficient ◽

Dye Coupling ◽

Cell Coupling ◽

Teratocarcinoma Cell ◽

Gap Junctional Communication ◽

Junctional Communication ◽

Gap Junctional ◽

Ionic Coupling ◽

Cell Cell

We examined the gap-junctional communication properties of a communication-defective cell line R5/3 and its communication-competent revertant H2T12. For these studies, we carried out microelectrode impalements to monitor ionic coupling and dye coupling. Our dye-injection experiments revealed that the H2T12 cells are much more efficient in dye coupling than the R5/3 cells. This latter observation is in agreement with the previous finding that the H2T12 cells are much better metabolically coupled than the R5/3 cells. With ionic coupling measurements, however, both cell lines exhibited similar levels of cell-cell coupling. The R5/3 cells demonstrated an ionic coupling coefficient of 0.19 +/− 0.011 (S.E.M.) and H2T12 a coupling coefficient of 0.25 +/− 0.009 (S.E.M.). These results in conjunction with observations from other studies indicate that the different experimental approaches for monitoring gap-junctional communication may have different levels of sensitivity for detecting as opposed to measuring the level of cell-cell coupling.

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Therapeutic effects of simvastatin on Galectin-3 and oxidative stress parameters in endotoxemic lung tissue

Bioscience Reports ◽

10.1042/bsr20180308 ◽

2018 ◽

Vol 38 (3) ◽

Cited By ~ 5

Author(s):

Hatice Yorulmaz ◽

Elif Ozkok ◽

Engin Kaptan ◽

Gulten Ates ◽

Sule Tamer

Keyword(s):

Oxidative Stress ◽

Lung Tissue ◽

Thiobarbituric Acid ◽

Statin Treatment ◽

Therapeutic Effects ◽

Acute Lung Inflammation ◽

Oxidative Stress Parameters ◽

Inflammatory Conditions ◽

Galectin 3 ◽

Stress Parameters

Galectins constitute of a soluble mammalian β-galactoside binding lectin family, which play homeostatic roles in the regulation of the cell cycle, and apoptosis, in addition to their inflammatory conditions. Galectin-3 has an important role in the regulation of various inflammatory conditions including endotoxemia, and airway inflammation. Statins, the key precursor inhibitors of 3-hydroxyl-3-methyl coenzyme A (HMG-CoA) reductase, may prevent the progression of inflammation in sepsis after prior statin treatment. Endotoxemia leads to the formation of oxidative stress parameters in proteins, carbohydrates, and DNA. In the present study, we aimed to show the effects of simvastatin on Galectin-3, and glutathione reductase (GR), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and thiobarbituric acid reactive substances (TBARS) levels in lung tissue of rats which were treated with lipopolysaccharides (LPS) during the early phase of sepsis. Rats were divided into four groups as the control, LPS (20 mg/kg), simvastatin (20 mg/kg), and simvastatin+LPS group. Galectin-3 expression in formalin-fixed paraffin-embedded lung tissue sections was demonstrated by using the immunohistochemistry methods. There were reduced densities, and the decreased number of Galectin-3 immunoreactivities in the simvastatin+LPS group compared with the LPS group in the pneumocytes, and in the bronchial epithelium of lung tissue. In the LPS group, GR, GSH-Px, and SOD were found lower than the levels in simvastatin-treated LPS group (P<0.05, P<0.01, P<0.01 respectively) in the lung tissue. However, TBARS decreased in the simvastatin+LPS group compared with the levels in LPS group (P<0.001). Simvastatin attenuates LPS-induced oxidative acute lung inflammation, oxidative stress, and suppresses LPS-induced Galectin-3 expression in the lung tissue.

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Inhibition of gap junctional communication by polyunsaturated fatty acids in WB cells: evidence that connexin 43 is not hyperphosphorylated

Carcinogenesis ◽

10.1093/carcin/16.7.1505 ◽

1995 ◽

Vol 16 (7) ◽

pp. 1505-1511 ◽

Cited By ~ 22

Author(s):

Charles S. T. Hii ◽

Antonio Ferrante ◽

Simon Schmidt ◽

Deborah A. Rathjen ◽

Brenton S. Robinson ◽

...

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Connexin 43 ◽

Gap Junctional Communication ◽

Junctional Communication ◽

Gap Junctional

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Hormonal Regulation of Connexin 43 Expression and Gap Junctional Communication in Human Osteoblastic Cells.

Cell Structure and Function ◽

10.1247/csf.19.173 ◽

1994 ◽

Vol 19 (3) ◽

pp. 173-177 ◽

Cited By ~ 39

Author(s):

Hideki Chiba ◽

Norimasa Sawada ◽

Masahito Oyamada ◽

Takashi Kojima ◽

Kousuke Iba ◽

...

Keyword(s):

Hormonal Regulation ◽

Connexin 43 ◽

Osteoblastic Cells ◽

Gap Junctional Communication ◽

Junctional Communication ◽

Gap Junctional ◽

Human Osteoblastic Cells

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Approaches to Study Gap Junctional Coupling

Frontiers in Cellular Neuroscience ◽

10.3389/fncel.2021.640406 ◽

2021 ◽

Vol 15 ◽

Author(s):

Jonathan Stephan ◽

Sara Eitelmann ◽

Min Zhou

Keyword(s):

Cell Types ◽

Cellular Heterogeneity ◽

Wide Field ◽

Tissue Slices ◽

Gap Junctional Communication ◽

Junctional Communication ◽

Junctional Coupling ◽

Gap Junctional ◽

Gap Junctional Coupling ◽

Different Cell Types

Astrocytes and oligodendrocytes are main players in the brain to ensure ion and neurotransmitter homeostasis, metabolic supply, and fast action potential propagation in axons. These functions are fostered by the formation of large syncytia in which mainly astrocytes and oligodendrocytes are directly coupled. Panglial networks constitute on connexin-based gap junctions in the membranes of neighboring cells that allow the passage of ions, metabolites, and currents. However, these networks are not uniform but exhibit a brain region-dependent heterogeneous connectivity influencing electrical communication and intercellular ion spread. Here, we describe different approaches to analyze gap junctional communication in acute tissue slices that can be implemented easily in most electrophysiology and imaging laboratories. These approaches include paired recordings, determination of syncytial isopotentiality, tracer coupling followed by analysis of network topography, and wide field imaging of ion sensitive dyes. These approaches are capable to reveal cellular heterogeneity causing electrical isolation of functional circuits, reduced ion-transfer between different cell types, and anisotropy of tracer coupling. With a selective or combinatory use of these methods, the results will shed light on cellular properties of glial cells and their contribution to neuronal function.

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