scholarly journals Connexin 43 Expression on Peripheral Blood Eosinophils: Role of Gap Junctions in Transendothelial Migration

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Harissios Vliagoftis ◽  
Cory Ebeling ◽  
Ramses Ilarraza ◽  
Salahaddin Mahmudi-Azer ◽  
Melanie Abel ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Peripheral Blood ◽  
Connexin 43 ◽  
Transendothelial Migration ◽  
Glycyrrhetinic Acid ◽  
Dependent Manner ◽  
Dye Transfer ◽  
Blood Eosinophils

Eosinophils circulate in the blood and are recruited in tissues during allergic inflammation. Gap junctions mediate direct communication between adjacent cells and may represent a new way of communication between immune cells distinct from communication through cytokines and chemokines. We characterized the expression of connexin (Cx)43 by eosinophils isolated from atopic individuals using RT-PCR, Western blotting, and confocal microscopy and studied the biological functions of gap junctions on eosinophils. The formation of functional gap junctions was evaluated measuring dye transfer using flow cytometry. The role of gap junctions on eosinophil transendothelial migration was studied using the inhibitor 18-a-glycyrrhetinic acid. Peripheral blood eosinophils express Cx43 mRNA and protein. Cx43 is localized not only in the cytoplasm but also on the plasma membrane. The membrane impermeable dye BCECF transferred from eosinophils to epithelial or endothelial cells following coculture in a dose and time dependent fashion. The gap junction inhibitors 18-a-glycyrrhetinic acid and octanol did not have a significant effect on dye transfer but reduced dye exit from eosinophils. The gap junction inhibitor 18-a-glycyrrhetinic acid inhibited eosinophil transendothelial migration in a dose dependent manner. Thus, eosinophils from atopic individuals express Cx43 constitutively and Cx43 may play an important role in eosinophil transendothelial migration and function in sites of inflammation.

scholarly journals Androgen Regulates the Expression and Function of Connexin 43 in Granulosa Cells via the PKC Signalling Pathway

2021 ◽  
Author(s):  
Yangyang Zhang ◽  
Yang Xu ◽  
Yanrong Kuai ◽  
Sheng Wang ◽  
Jiao Yu
Keyword(s):  
Gap Junction ◽  
Granulosa Cells ◽  
Connexin 43 ◽  
Ovarian Response ◽  
Signalling Pathway ◽  
Dependent Manner ◽  
Dye Transfer ◽  
Concentration Dependent Manner ◽  
Physiological Level

Abstract Background: Poor ovarian response (POR) is one of the most challenging issues in assisted reproductive technology. Given the importance of androgens in follicle recruitment, growth and development, domestic and foreign reproductive centers have added androgen as an adjuvant to in vitro fertilization protocols for patients with POR to improve the ovarian response. The mechanism underlying the effects of androgens is unclear. The aim of this research was to study the effects of testosterone on granulosa cells and the underlying mechanisms.Methods: The human ovarian granulosa cell line KGN was treated with testosterone at various concentrations, an androgen receptor antagonist (flutamide) and a protein kinase C (PKC) inhibitor (GF109203X). The protein levels of PKC and phosphorylated connexin 43 (p-Cx43) were measured using Western blot analysis. The location and distribution of Cx43 and p-Cx43 were determined by immunofluorescence. Gap junction intercellular communication (GJIC) was monitored using the scrape loading/dye transfer method.Results: The results showed that treatment with testosterone at a physiological level significantly increased the PKC and p-Cx43 levels and GJIC activity in a concentration-dependent manner. However, the expression of PKC, p-Cx43 levels and GJIC activity in the cells treated with testosterone above physiological concentrations (10-5 M) decreased compared with those in the cells treated with 10-7 M testosterone. Compared to the 10-7 M testosterone-treated cells, the KGN cells treated with flutamide had much lower levels of PKC and p-Cx43. The levels of p-Cx43 and GJIC activity in the GF109203X-treated group were decreased compared to those in the 10-7 M testosterone group. Immunofluorescence showed that testosterone treatment had no effect on the localization and distribution of gap junction proteins.Conclusions: This study suggests that androgen can increase GJIC activity in granulosa cells by phosphorylating Cx43 via the PKC signalling pathway to promote oocyte development. The results of this study might provide a theoretical basis for androgen pretreatment of patients with POR.

scholarly journals Androgen regulates the expression and function of connexin 43 in granulosa cells via the PKC signalling pathway

2021 ◽  
Author(s):  
Yangyang Zhang ◽  
Yang Xu ◽  
Yanrong Kuai ◽  
Sheng Wang ◽  
Jiao Yu
Keyword(s):  
Gap Junction ◽  
Granulosa Cells ◽  
Connexin 43 ◽  
Ovarian Response ◽  
Signalling Pathway ◽  
Dependent Manner ◽  
Dye Transfer ◽  
Concentration Dependent Manner ◽  
Physiological Level

Abstract Background Poor ovarian response (POR) is one of the most challenging issues in assisted reproductive technology. Given the importance of androgens in follicle recruitment, growth and development, domestic and foreign reproductive centers have added androgen as an adjuvant to in vitro fertilization protocols for patients with POR to improve the ovarian response. The mechanism underlying the effects of androgens is unclear. The aim of this research was to study the effects of testosterone on granulosa cells and the underlying mechanisms. Methods The human ovarian granulosa cell line KGN was treated with testosterone at various concentrations, an androgen receptor antagonist (flutamide) and a protein kinase C (PKC) inhibitor (GF109203X). The protein levels of PKC and phosphorylated connexin 43 (p-Cx43) were measured using Western blot analysis. The location and distribution of Cx43 and p-Cx43 were determined by immunofluorescence. Gap junction intercellular communication (GJIC) was monitored using the scrape loading/dye transfer method. Results The results showed that treatment with testosterone at a physiological level significantly increased the PKC and p-Cx43 levels and GJIC activity in a concentration-dependent manner. However, the expression of PKC, p-Cx43 levels and GJIC activity in the cells treated with testosterone above physiological concentrations (10− 5 M) decreased compared with those in the cells treated with 10− 7 M testosterone. Compared to the 10− 7 M testosterone-treated cells, the KGN cells treated with flutamide had much lower levels of PKC and p-Cx43. The levels of p-Cx43 and GJIC activity in the GF109203X-treated group were decreased compared to those in the 10− 7 M testosterone group. Immunofluorescence showed that testosterone treatment had no effect on the localization and distribution of gap junction proteins. Conclusions This study suggests that androgen can increase GJIC activity in granulosa cells by phosphorylating Cx43 via the PKC signalling pathway to promote oocyte development. The results of this study might provide a theoretical basis for androgen pretreatment of patients with POR.

scholarly journals Astroglial connexins and cognition: memory formation or deterioration?

2020 ◽  
Vol 40 (1) ◽  
Author(s):  
Jin-Ting He ◽  
Xiao-Yan LI ◽  
Le Yang ◽  
Xin Zhao
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Connexin 43 ◽  
Memory Formation ◽  
Gap Junction Communication ◽  
Different Types ◽  
Excessive Activation ◽  
High Conductance ◽  
Junction Proteins

Abstract Connexins are the membrane proteins that form high-conductance plasma membrane channels and are the important constituents of gap junctions and hemichannels. Among different types of connexins, connexin 43 is the most widely expressed and studied gap junction proteins in astrocytes. Due to the key involvement of astrocytes in memory impairment and abundant expression of connexins in astrocytes, astroglial connexins have been projected as key therapeutic targets for Alzheimer’s disease. On the other hand, the role of connexin gap junctions and hemichannels in memory formation and consolidation has also been reported. Moreover, deletion of these proteins and loss of gap junction communication result in loss of short-term spatial memory. Accordingly, both memory formation and memory deteriorating functions of astrocytes-located connexins have been documented. Physiologically expressed connexins may be involved in the memory formation, while pathologically increased expression of connexins with consequent excessive activation of astrocytes may induce neuronal injury and cognitive decline. The present review describes the memory formation as well as memory deteriorating functions of astroglial connexins in memory disorders of different etiology with possible mechanisms.

Connexin 43 ubiquitination determines the fate of gap junctions: restrict to survive

2015 ◽  
Vol 43 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Teresa M. Ribeiro-Rodrigues ◽  
Steve Catarino ◽  
Maria J. Pinho ◽  
Paulo Pereira ◽  
Henrique Girao
Keyword(s):  
Plasma Membrane ◽  
Gap Junctions ◽  
Gap Junction ◽  
Intercellular Communication ◽  
Connexin 43 ◽  
Transmembrane Proteins ◽  
Post Translational Modifications ◽  
Gap Junction Intercellular Communication

Connexins (Cxs) are transmembrane proteins that form channels which allow direct intercellular communication (IC) between neighbouring cells via gap junctions. Mechanisms that modulate the amount of channels at the plasma membrane have emerged as important regulators of IC and their de-regulation has been associated with various diseases. Although Cx-mediated IC can be modulated by different mechanisms, ubiquitination has been described as one of the major post-translational modifications involved in Cx regulation and consequently IC. In this review, we focus on the role of ubiquitin and its effect on gap junction intercellular communication.

scholarly journals Evidence for a Role of Connexin 43 in Trigeminal Pain Using RNA Interference In Vivo

2008 ◽  
Vol 100 (6) ◽  
pp. 3064-3073 ◽  
Author(s):  
Peter T. Ohara ◽  
Jean-Philippe Vit ◽  
Aditi Bhargava ◽  
Luc Jasmin
Keyword(s):  
Rna Interference ◽  
Gap Junctions ◽  
Gap Junction ◽  
Glial Cells ◽  
Trigeminal Ganglion ◽  
Connexin 43 ◽  
Infraorbital Nerve ◽  
Nociceptive Behavior ◽  
Cx43 Expression

The importance of glial cells in the generation and maintenance of neuropathic pain is becoming widely accepted. We examined the role of glial-specific gap junctions in nociception in the rat trigeminal ganglion in nerve-injured and -uninjured states. The connexin 43 (Cx43) gap-junction subunit was found to be confined to the satellite glial cells (SGCs) that tightly envelop primary sensory neurons in the trigeminal ganglion and we therefore used Cx43 RNA interference (RNAi) to alter gap-junction function in SGCs. Using behavioral evaluation, together with immunocytochemical and Western blot monitoring, we show that Cx43 increased in the trigeminal ganglion in rats with a chronic constriction injury (CCI) of the infraorbital nerve. Reducing Cx43 expression using RNAi in CCI rats reduced painlike behavior, whereas in non-CCI rats, reducing Cx43 expression increased painlike behavior. The degree of painlike behavior in CCI rats and intact, Cx43-silenced rats was similar. Our results support previous suggestions that increases in glial gap junctions after nerve injury increases nociceptive behavior but paradoxically the reduction of gap junctions in normal ganglia also increases nociceptive behavior, possibly a reflection of the multiple functions performed by glia.

scholarly journals First Responders to Hyperosmotic Stress in Murine Astrocytes: Connexin 43 Gap Junctions Are Subject to an Immediate Ultrastructural Reorganization

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1307
Author(s):  
Anja Beckmann ◽  
Johanna Recktenwald ◽  
Alice Ferdinand ◽  
Alexander Grißmer ◽  
Carola Meier
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Connexin 43 ◽  
Sucrose Solution ◽  
Freeze Fracture ◽  
First Responders ◽  
Hyperosmotic Stress ◽  
Ultrastructural Changes ◽  
Dye Transfer ◽  
Gap Junctional Intercellular Communication

In a short-term model of hyperosmotic stress, primary murine astrocytes were stimulated with a hyperosmolar sucrose solution for five minutes. Astrocytic gap junctions, which are mainly composed of Connexin (Cx) 43, displayed immediate ultrastructural changes, demonstrated by freeze–fracture replica immunogold labeling: their area, perimeter, and distance of intramembrane particles increased, whereas particle numbers per area decreased. Ultrastructural changes were, however, not accompanied by changes in Cx43 mRNA expression. In contrast, transcription of the gap junction regulator zonula occludens (ZO) protein 1 significantly increased, whereas its protein expression was unaffected. Phosphorylation of Serine (S) 368 of the Cx43 C–terminus has previously been associated with gap junction disassembly and reduction in gap junction communication. Hyperosmolar sucrose treatment led to enhanced phosphorylation of Cx43S368 and was accompanied by inhibition of gap junctional intercellular communication, demonstrated by a scrape loading-dye transfer assay. Taken together, Cx43 gap junctions are fast reacting elements in response to hyperosmolar challenges and can therefore be considered as one of the first responders to hyperosmolarity. In this process, phosphorylation of Cx43S368 was associated with disassembly of gap junctions and inhibition of their function. Thus, modulation of the gap junction assembly might represent a target in the treatment of brain edema or trauma.

Role of FSH and triiodothyronine in Sertoli cell development expressed by formation of connexin 43-based gap junctions

2011 ◽  
Vol 315A (6) ◽  
pp. 329-336 ◽  
Author(s):  
Katarzyna Marchlewska ◽  
Krzysztof Kula ◽  
Renata Walczak-Jedrzejowska ◽  
Elzbieta Oszukowska ◽  
Eliza Filipiak ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Sertoli Cell ◽  
Connexin 43 ◽  
Cell Development

Analysis of distribution patterns of gap junctions during development of embryonic chick facial primordia and brain

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 509-522
Author(s):  
R. Minkoff ◽  
S.B. Parker ◽  
E.L. Hertzberg
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Uniform Distribution ◽  
Rat Liver ◽  
Connexin 43 ◽  
Cell Communication ◽  
Exterior Surface ◽  
Junction Protein ◽  
Primary Palate ◽  
Gap Junction Protein

Gap junction distribution in the facial primordia of chick embryos at the time of primary palate formation was studied employing indirect immunofluorescence localization with antibodies to gap junction proteins initially identified in rat liver (27 × 10(3) Mr, connexin 32) and heart (43 × 10(3) Mr, connexin 43). Immunolocalization with antibodies to the rat liver gap junction protein (27 × 10(3) Mr) demonstrated a ubiquitous and uniform distribution in all regions of the epithelium and mesenchyme except the nasal placode. In the placodal epithelium, a unique non-random distribution was found characterized by two zones: a very heavy concentration of signal in the superficial layer of cells adjacent to the exterior surface and a region devoid of detectable signal in the interior cell layer adjacent to the mesenchyme. This pattern was seen during all stages of placode invagination that were examined. The separation of gap junctions in distinct cell layers was unique to the nasal placode, and was not found in any other region of the developing primary palate. One other tissue was found that exhibited this pattern-the developing neural epithelium of the brain and retina. These observations suggest the presence of region-specific signaling mechanisms and, possibly, an impedance of cell communication among subpopulations of cells in these structures at critical stages of development. Immunolocalization with antibodies to the ‘heart’ 43 × 10(3) Mr gap junction protein also revealed the presence of gap junction protein in facial primordia and neural epithelium. A non-uniform distribution of immunoreactivity was also observed for connexin 43.

Heart gap junction preparations reveal hemiplaques by atomic force microscopy

1995 ◽  
Vol 268 (4) ◽  
pp. C968-C977 ◽  
Author(s):  
R. Lal ◽  
S. A. John ◽  
D. W. Laird ◽  
M. F. Arnsdorf
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
Long Range ◽  
Connexin 43 ◽  
Plasma Membranes ◽  
Aqueous Media ◽  
Freeze Fracture ◽  
Isolated Rat Heart ◽  
Hexagonal Packing ◽  
Atomic Force

Current structural models of gap junctions indicate two apposed plasma membranes with hexagonally packed hemichannels in each membrane aligning end to end. These channels connect the cytoplasms of contacting cells. Images of isolated rat heart gap junctions have been made with the atomic force microscope in aqueous media. We show that native cardiac gap junctions have a thickness of 25 +/- 0.6 nm. This decreases to 17 nm when they are treated with trypsin, which is known to remove some cytoplasmic components of connexin 43. Imaging shows subunits with a center to center spacing of approximately 9-10 nm and long range hexagonal packing, measurements in agreement with studies using freeze-fracture and negative-stain electron microscopy. In addition to gap junctions, we imaged structures that had all the characteristics of native gap junctions except their thickness was limited to 9-11 nm. They also show long range hexagonal packing and center to center spacing of 9-10 nm. These structures decrease in thickness, to 6-9 nm, when treated with trypsin. We have called these structures hemiplaques. They appear to be present endogenously in the preparation, as we have ruled out their being an artifact of imaging by AFM. However, it remains to be determined if they are a consequence of the procedure used in isolating gap junctions or a possible intermediary in gap junction formation.

Sign in / Sign up

Export Citation Format

Share Document