Gap junction proteins and cell-cell communication in the three functional zones of the adrenal gland

Mouse and monkey adrenal glands were used to study the relationships between gap junction protein expression, intercellular communication and adrenal zonation. Dye communication patterns were determined by incubating freshly excised and hemisected adrenal glands in Lucifer yellow, a gap junction permeable fluorescent dye. Immunohistochemical techniques were used to localize adrenal gap junction proteins. The combination of these two techniques permitted the correlation of gap junction proteins with dye transfer and hormone responses in specialized regions of the adrenal cortex. Lucifer yellow dye communication was most pronounced in the inner glucocorticoid/androgen-producing regions (zona fasciculata/zona reticularis), but was virtually absent in the outer mainly mineralocorticoid-producing region (zona glomerulosa). This pattern of dye communication was coincident with immunohistochemical localization of the gap junction protein, alpha(1)Cx43. The variations in communication and alpha(1)Cx43 expression within the adrenal cortex are thought to be relevant to normal physiological regulation of the adrenal gland.

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Involvement of the Gap Junction Protein, Connexin43, in the Formation and Function of Invadopodia in the Human U251 Glioblastoma Cell Line

Cells ◽

10.3390/cells9010117 ◽

2020 ◽

Vol 9 (1) ◽

pp. 117 ◽

Cited By ~ 3

Author(s):

Amandine Chepied ◽

Zeinaba Daoud-Omar ◽

Annie-Claire Meunier-Balandre ◽

Dale W. Laird ◽

Marc Mesnil ◽

...

Keyword(s):

Gap Junction ◽

Molecular Mechanisms ◽

Glioblastoma Cells ◽

Dynamic Interactions ◽

Cx43 Expression ◽

Junction Protein ◽

Gap Junction Protein ◽

And Function ◽

Low Cell Density ◽

Invadopodia Formation

The resistance of glioblastomas to treatments is mainly the consequence of their invasive capacities. Therefore, in order to better treat these tumors, it is important to understand the molecular mechanisms which are responsible for this behavior. Previous work suggested that gap junction proteins, the connexins, facilitate the aggressive nature of glioma cells. Here, we show that one of them—connexin43 (Cx43)—is implicated in the formation and function of invadopodia responsible for invasion capacity of U251 human glioblastoma cells. Immunofluorescent approaches—combined with confocal analyses—revealed that Cx43 was detected in all the formation stages of invadopodia exhibiting proteolytic activity. Clearly, Cx43 appeared to be localized in invadopodia at low cell density and less associated with the establishment of gap junctions. Accordingly, lower extracellular matrix degradation correlated with less mature invadopodia and MMP2 activity when Cx43 expression was decreased by shRNA strategies. Moreover, the kinetics of invadopodia formation could be dependent on Cx43 dynamic interactions with partners including Src and cortactin. Interestingly, it also appeared that invadopodia formation and MMP2 activity are dependent on Cx43 hemichannel activity. In conclusion, these results reveal that Cx43 might be involved in the formation and function of the invadopodia of U251 glioblastoma cells.

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The Role of Gap Junction Proteins in Infertility

International Journal of Infertility & Fetal Medicine ◽

10.5005/jp-journals-10016-1002 ◽

2010 ◽

Vol 1 (1) ◽

pp. 11-18 ◽

Cited By ~ 2

Author(s):

Piyush Tripathi ◽

Manorama Tripathi

Keyword(s):

Gap Junction ◽

Critical Role ◽

Growth Control ◽

Successful Outcome ◽

Basic Unit ◽

Junction Protein ◽

Gap Junction Proteins ◽

Infertility Patients ◽

Junction Proteins

ABSTRACT Testis and ovary serve an important role of producing male and female gametes. Their normal functioning is very important for the proper formation of sperm and ovum and thus has a critical role in the successful fertility outcome. Synchronized activity of various cells in the gonads is needed to provide favorable niche for the growth and development of the germ cells. Among various ways of cellular communication, intercellular communication is mediated by gap junctions, which provides open but selective exchange of ion and molecules of restricted size between two adjoining cells. The basic unit of gap junction is connexins. Their important role has been speculated in the maintenance of homeostasis, morphogenesis, cell differentiation, and growth control in higher organisms. The expression of gap junction proteins in reproductive tissues has drawn the attention and interest of researcher to investigate their role in the reproductive outcome. The reports about the correlation of gap junction protein expression pattern in infertility patients and in animal models have suggested their implication in fertility. Some of these gap junction proteins seem to have redundant functions, whereas some could be very critical in the normal fertility and could not be dispensable for the successful outcome of the reproduction.

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A dominant connexin43 mutant does not have dominant effects on gap junction coupling in astrocytes

Neuron Glia Biology ◽

10.1017/s1740925x11000019 ◽

2010 ◽

Vol 6 (4) ◽

pp. 213-223 ◽

Cited By ~ 3

Author(s):

Sameh Wasseff ◽

Charles K. Abrams ◽

Steven S. Scherer

Keyword(s):

Gap Junction ◽

Lucifer Yellow ◽

Brain Slices ◽

Gene Encoding ◽

Transfected Cells ◽

Dominant Phenotype ◽

Sulforhodamine B ◽

Junction Protein ◽

The Central Nervous System ◽

Gap Junction Protein

Dominant mutations in GJA1, the gene encoding the gap junction protein connexin43 (Cx43), cause oculodentodigital dysplasia (ODDD), a syndrome affecting multiple tissues, including the central nervous system (CNS). We investigated the effects of the G60S mutant, which causes a similar, dominant phenotype in mice (Gja1Jrt/+). Astrocytes in acute brain slices from Gja1Jrt/+ mice transfer sulforhodamine-B comparably to that in their wild-type (WT) littermates. Further, astrocytes and cardiomyocytes cultured from Gja1Jrt/+ mice showed a comparable transfer of lucifer yellow to those from WT mice. In transfected cells, the G60S mutant formed gap junction (GJ) plaques but not functional channels. In co-transfected cells, the G60S mutant co-immunoprecipitated with WT Cx43, but did not diminish GJ coupling as measured by dual patch clamp. Thus, whereas G60S has dominant effects, it did not appreciably reduce GJ coupling.

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Amyloid-β regulates gap junction protein connexin 43 trafficking in cultured primary astrocytes

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.013705 ◽

2020 ◽

Vol 295 (44) ◽

pp. 15097-15111

Author(s):

Mahua Maulik ◽

Lakshmy Vasan ◽

Abhishek Bose ◽

Saikat Dutta Chowdhury ◽

Neelanjana Sengupta ◽

...

Keyword(s):

Gap Junctions ◽

Gap Junction ◽

Connexin 43 ◽

Cx43 Expression ◽

Chemical Chaperone ◽

Junction Protein ◽

Gap Junction Coupling ◽

Gap Junction Protein ◽

Junction Coupling ◽

And Function

Altered expression and function of astroglial gap junction protein connexin 43 (Cx43) has increasingly been associated to neurotoxicity in Alzheimer disease (AD). Although earlier studies have examined the effect of increased β-amyloid (Aβ) on Cx43 expression and function leading to neuronal damage, underlying mechanisms by which Aβ modulates Cx43 in astrocytes remain elusive. Here, using mouse primary astrocyte cultures, we have examined the cellular processes by which Aβ can alter Cx43 gap junctions. We show that Aβ25-35 impairs functional gap junction coupling yet increases hemichannel activity. Interestingly, Aβ25-35 increased the intracellular pool of Cx43 with a parallel decrease in gap junction assembly at the surface. Intracellular Cx43 was found to be partly retained in the endoplasmic reticulum-associated cell compartments. However, forward trafficking of the newly synthesized Cx43 that already reached the Golgi was not affected in Aβ25-35-exposed astrocytes. Supporting this, treatment with 4-phenylbutyrate, a well-known chemical chaperone that improves trafficking of several transmembrane proteins, restored Aβ-induced impaired gap junction coupling between astrocytes. We further show that interruption of Cx43 endocytosis in Aβ25-35-exposed astrocytes resulted in their retention at the cell surface in the form of functional gap junctions indicating that Aβ25-35 causes rapid internalization of Cx43 gap junctions. Additionally, in silico molecular docking suggests that Aβ can bind favorably to Cx43. Our study thus provides novel insights into the cellular mechanisms by which Aβ modulates Cx43 function in astrocytes, the basic understanding of which is vital for the development of alternative therapeutic strategy targeting connexin channels in AD.

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Hypophysectomy Results in a Loss of Connexin Gap Junction Protein from the Adrenal Cortex

Endocrine Research ◽

10.3109/07435800009048571 ◽

2000 ◽

Vol 26 (4) ◽

pp. 561-570 ◽

Cited By ~ 11

Author(s):

K. T. Davis ◽

I. McDuffie ◽

L. A. Mawhinney ◽

S. A. Murray

Keyword(s):

Gap Junction ◽

Adrenal Cortex ◽

Junction Protein ◽

Gap Junction Protein

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Involvement of connexin 43 in meiotic maturation of bovine oocytes

Reproduction ◽

10.1530/rep.0.1220619 ◽

2001 ◽

pp. 619-628 ◽

Cited By ~ 54

Author(s):

C Vozzi ◽

A Formenton ◽

A Chanson ◽

A Senn ◽

R Sahli ◽

...

Keyword(s):

Gap Junction ◽

Oocyte Maturation ◽

Connexin 43 ◽

Lucifer Yellow ◽

Cumulus Cells ◽

Lower Amount ◽

Cx43 Expression ◽

Gap Junction Channels ◽

Junction Protein ◽

Bovine Oocytes

In ovarian follicles, cumulus cells provide the oocyte with small molecules that permit growth and control maturation. These nutrients reach the germinal cell through gap junction channels, which are present between the cumulus cells and the oocyte, and between the cumulus cells. In this study the involvement of intercellular communication mediated by gap junction channels on oocyte maturation of in vitro cultured bovine cumulus-oocyte complexes (COCs) was investigated. The stages of oocyte maturation were determined by Hoechst 33342 staining, which showed that 90% of COCs placed in the maturation medium for 24 h progress to the metaphase II stage. Bovine COC gap junction communication was disrupted initially using n-alkanols, which inhibit any passage through gap junctions. In the presence of 1-heptanol (3 mmol l(-1)) or octanol (3.0 mmol l(-1) and 0.3 mmol l(-1)), only 29% of the COCs reached metaphase II. Removal of the uncoupling agent was associated with restoration of oocyte maturation, indicating that treatment with n-alkanols was neither cytotoxic nor irreversible. Concentrations of connexin 43 (Cx43), the major gap junction protein expressed in the COCs, were decreased specifically using a recombinant adenovirus expressing the antisense Cx43 cDNA (Ad-asCx43). The efficacy of adenoviral infection was > 95% in cumulus cells evaluated after infection with recombinant adenoviruses expressing the green fluorescence protein. RT-PCR performed on total RNA isolated from Ad-asCx43-infected COCs showed that the rat Cx43 cDNA was transcribed. Western blot analysis revealed a three-fold decrease in Cx43 expression in COCs expressing the antisense RNA for Cx43. Injection of cumulus cells with Lucifer yellow demonstrated further that the resulting lower amount of Cx43 in infected COCs is associated with a two-fold decrease in the extent of coupling between cumulus cells. In addition, oocyte maturation was decreased by 50% in the infected COC cultures. These results indicate that Cx43-mediated communication between cumulus cells plays a crucial role in maturation of bovine oocytes.

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Comparative characterization of the 21-kD and 26-kD gap junction proteins in murine liver and cultured hepatocytes.

The Journal of Cell Biology ◽

10.1083/jcb.108.3.1039 ◽

1989 ◽

Vol 108 (3) ◽

pp. 1039-1051 ◽

Cited By ~ 229

Author(s):

O Traub ◽

J Look ◽

R Dermietzel ◽

F Brümmer ◽

D Hülser ◽

...

Keyword(s):

Gap Junction ◽

Rat Liver ◽

Plasma Membranes ◽

Lucifer Yellow ◽

Adult Brain ◽

Cultured Hepatocytes ◽

Embryonic Mouse ◽

Thin Sections ◽

Gap Junction Proteins ◽

Junction Proteins

Affinity-purified antibodies to mouse liver 26- and 21-kD gap junction proteins have been used to characterize gap junctions in liver and cultured hepatocytes. Both proteins are colocalized in the same gap junction plaques as shown by double immunofluorescence and immunoelectron microscopy. In the lobules of rat liver, the 21-kD immunoreactivity is detected as a gradient of fluorescent spots on apposing plasma membranes, the maximum being in the periportal zone and a faint reaction in the perivenous zone. In contrast, the 26-kD immunoreactivity is evenly distributed in fluorescent spots on apposing plasma membranes throughout the rat liver lobule. Immunoreactive sites with anti-21 kD shown by immunofluorescence are also present in exocrine pancreas, proximal tubules of the kidney, and the epithelium of small intestine. The 21-kD immunoreactivity was not found in thin sections of myocardium and adult brain cortex. Subsequent to partial rat hepatectomy, both the 26- and 21-kD proteins first decrease and after approximately 2 d increase again. By comparison of the 26- and 21-kD immunoreactivity in cultured embryonic mouse hepatocytes, we found (a) the same pattern of immunoreactivity on apposing plasma membranes and colocalization within the same plaque, (b) a similar decrease after 1 d and subsequent increase after 3 d of both proteins, (c) cAMP-dependent in vitro phosphorylation of the 26-kD but not of the 21-kD protein, and (d) complete inhibition of intercellular transfer of Lucifer Yellow in all hepatocytes microinjected with anti-26 kD and, in most cases, partial inhibition of dye transfer after injection of anti-21 kD. Our results indicate that both the 26-kD and the 21-kD proteins are functional gap junction proteins.

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Abstract 3860: Arrhythmia Vulnerability of Aged Haploinsufficient Cx43 Mice is Determined by Heterogeneous Downregulation of Cx43 Combined with Increased Fibrosis

Circulation ◽

10.1161/circ.118.suppl_18.s_494 ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

John A Jansen ◽

Toon A van Veen ◽

Astrid A Bosch ◽

Roel van der Nagel ◽

Marc A Vos ◽

...

Keyword(s):

Gap Junction ◽

Ventricular Arrhythmias ◽

Interstitial Fibrosis ◽

Cx43 Expression ◽

Slow Conduction ◽

Junction Protein ◽

Gap Junction Protein ◽

Heterogeneous Reduction ◽

Perfused Hearts ◽

Activation Mapping

Background: Reduced gap junction expression and increased collagen deposition are commonly found in ventricles of electrically remodeled diseased hearts. Their interactive contribution to slow conduction and increased arrhythmogeneity is, however, unclear. In this study, we investigated the effect of increased fibrosis with normal or reduced levels of the ventricular gap junction protein Cx43 on impulse propagation and arrhythmogeneity. Methods: 11 Cx43fl/fl (Control) and 13 Cx43CreER(T)/fl mice (expressing only 50% of Cx43 protein compared to control; Cx43HZ) were aged to 20 months. Epicardial activation mapping (208 electrode terminals) of right (RV) and left (LV) ventricle was performed on Langendorff perfused hearts. Effective refractory period (ERP) was determined by premature stimulation and arrhythmia inducibility was tested by 1–3 premature stimuli and burst pacing. Epicardial conduction velocity longitudinal (CVL) and transverse (CVT) to fiber orientation and inhomogeneity of conduction was determined during S1S1 pacing (150 ms). Cx43, N-cadherin expression, and tissue collagen content was determined by (immuno)histology and Western blotting. Results: Sustained ventricular arrhythmias were induced in 0/11 control and 8/13 Cx43HZ mice (p<0.01). CVL and CVT were unchanged, except for CVT in RV, which was decreased from 48.2±2 to 39.3±1.8 cm/s (Control vs Cx43HZ, p<0.05). In RV, ERP was decreased from 78.2±6.0 to 53.1±3.3 ms (Control vs Cx43HZ, p<0.05). In both RV and LV, inhomogeneity of conduction was significantly higher in Cx43HZ mice with arrhythmias (VT+), compared to both Control and Cx43HZ mice without arrhythmias (VT−). Cx43 expression levels were comparable between VT+ and VT- Cx43HZ mice, though strongly reduced compared to Control. However, Cx43 distribution was very heterogeneous in VT+ mice with large areas devoid of Cx43 while N-cadherin was unaffected, indicating the presence of intact intercalated disks. Compared to Control interstitial fibrosis was increased in Cx43HZ mice, but more pronounced in VT+ Cx43HZ mice when compared to Cx43HZ VT- mice. Conclusions: Combined heterogeneous reduction of Cx43 and increased fibrosis strongly enhance arrhythmogenic vulnerability in aged haploinsufficient Cx43 mice.

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Connecting Exosomes and Connexins

Cancers ◽

10.3390/cancers11040476 ◽

2019 ◽

Vol 11 (4) ◽

pp. 476 ◽

Cited By ~ 4

Author(s):

Joanna Gemel ◽

John Kilkus ◽

Glyn Dawson ◽

Eric Beyer

Keyword(s):

Gap Junction ◽

Extracellular Vesicles ◽

Recipient Cell ◽

Adherens Junction ◽

Adherens Junction Protein ◽

Junction Protein ◽

Endoplasmic Reticulum Protein ◽

Gap Junction Protein ◽

Junction Proteins

Intercellular communication is accomplished by passage of ions and small molecules through gap junction channels in directly contacting cells or by secretion and response to transmitters, hormones and extracellular vesicles in cells that are distant from each other. Recent studies have suggested that there may be overlap of these processes; specifically, small extracellular vesicles may contain subunit gap junction proteins, connexins. We isolated and analyzed extracellular vesicles secreted by cultured microvascular endothelial cells. These vesicles had a diameter of ~120 nm. They contained four exosomal proteins (flotillin-1, CD63, CD81 and Alix) and the gap junction protein, connexin43. They did not contain an endoplasmic reticulum protein (Grp94) or an adherens junction protein (VE-cadherin). Secretion of vesicles was increased by treatment of the cells with staurosporine. Our data confirm that the gap junction protein, connexin43, can be secreted in vesicles with the properties of exosomes. Although the role of vesicular connexin is not clearly known, we speculate that it might participate in docking/fusion of the exosomes with the recipient cell, transmission of vesicular contents, or cellular signaling.

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Titration of the gap junction protein Connexin43 reduces atherogenesis

Thrombosis and Haemostasis ◽

10.1160/th13-09-0773 ◽

2014 ◽

Vol 112 (08) ◽

pp. 390-401 ◽

Cited By ~ 12

Author(s):

Sandrine Morel ◽

Marc Chanson ◽

Thien D. Nguyen ◽

Aaron M. Glass ◽

Maya Z. Sarieddine ◽

...

Keyword(s):

Gap Junction ◽

Fetal Liver ◽

Low Density Lipoprotein ◽

Relative Proportion ◽

Density Lipoprotein ◽

Complement Components ◽

Cx43 Expression ◽

Beneficial Effects ◽

Junction Protein ◽

Gap Junction Protein

SummaryUbiquitous reduction of the gap junction protein Connexin43 (Cx43) in mice provides beneficial effects on progression and composition of atherosclerotic lesions. Cx43 is expressed in multiple atheroma-associated cells but its function in each cell type is not known. To examine specifically the role of Cx43 in immune cells, we have lethally irradiated low-density lipoprotein receptor-deficient mice and reconstituted with Cx43+/+, Cx43+/− or Cx43−/− haematopoietic fetal liver cells. Progression of atherosclerosis was significantly lower in aortic roots of Cx43+/− chimeras compared with Cx43+/+ and Cx43−/− chimeras, and their plaques contained significantly less neutrophils. The relative proportion of circulating leukocytes was similar between the three groups. Interestingly, the chemoattraction of neutrophils, which did not express Cx43, was reduced in response to supernatant secreted by Cx43+/− macrophages in comparison with the ones of Cx43+/+ and Cx43−/− macrophages. Cx43+/− macrophages did not differ from Cx43+/+ and Cx43−/− macrophages in terms of M1/M2 polarisation but show modified gene expression for a variety chemokines and complement components. In conclusion, titration of Cx43 expression in bone marrow-derived macrophages reduces atherosclerotic plaque formation and chemoattraction of neutrophils to the lesions.

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