Connexin 43 mediates endothelium-derived hyperpolarizing factor-induced vasodilatation in subcutaneous resistance arteries from healthy pregnant women

2007 ◽  
Vol 292 (2) ◽  
pp. H1026-H1032 ◽  
Author(s):  
Ninian N. Lang ◽  
Leonid Luksha ◽  
David E. Newby ◽  
Karolina Kublickiene
Keyword(s):  
Gap Junctions ◽  
Pregnant Women ◽  
Connexin 43 ◽  
Subcutaneous Fat ◽  
Cyclooxygenase Inhibitors ◽  
Elective Cesarean Section ◽  
Resistance Arteries ◽  
Cx43 Expression ◽  
Elective Cesarean ◽  
Oxide Synthase

The role of gap junctions in endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation of human arteries was assessed using connexin mimetic peptides (CMPs) designated 37,43Gap27, 40Gap27, and 43Gap26 according to homology with the major vascular connexins (Cx37, Cx40, and Cx43). Resistance arteries were obtained from subcutaneous fat biopsies of healthy pregnant women undergoing elective cesarean section. Endothelium-dependent vasodilatation to bradykinin (BK) was assessed using wire myography. Nω-nitro-l-arginine methyl ester (l-NAME) and indomethacin (nitric oxide synthase and cyclooxygenase inhibitors, respectively) attenuated maximal relaxation to BK (Rmax) by ∼50%. Coincubation with l-NAME, indomethacin, and the combined CMPs (37,43Gap27, 40Gap27, and 43Gap26) almost abolished relaxation to BK (Rmax = 12.2 ± 3.7%). In arteries incubated with l-NAME and indomethacin, the addition of either 37,43Gap27 or 40Gap27 had no significant effect on Rmax, whereas 43Gap26 caused marked inhibition (Rmax = 21 ± 6.4%, P = 0.005 vs. l-NAME plus indomethacin alone) that was similar to that of the triple combination. Endothelium-independent vasorelaxation was unaffected by CMPs, l-NAME, or indomethacin. Immunohistochemistry demonstrated Cx37, Cx40, and Cx43 expression in the endothelium and vascular smooth muscle. In pregnant women, EDHF-mediated vasorelaxation of subcutaneous resistance arteries is dependent on Cx43 and gap junctions.

CX43 expression, phosphorylation, and distribution in the normal and autoimmune orchitic testis with a look at gap junctions joining germ cell to germ cell

2011 ◽  
Vol 300 (1) ◽  
pp. R121-R139 ◽  
Author(s):  
R.-Marc Pelletier ◽  
Casimir D. Akpovi ◽  
Li Chen ◽  
Robert Day ◽  
María L. Vitale
Keyword(s):  
Cell Differentiation ◽  
Gap Junctions ◽  
Germ Cell ◽  
Sertoli Cell ◽  
Sertoli Cells ◽  
Seminiferous Tubule ◽  
Connexin 43 ◽  
Cx43 Expression ◽  
Cx43 Protein ◽  
Cx43 Mrna

Spermatogenesis requires connexin 43 (Cx43).This study examines normal gene transcription, translation, and phosphorylation of Cx43 to define its role on germ cell growth and Sertoli cell's differentiation, and identifies abnormalities arising from spontaneous autoimmune orchitis (AIO) in mink, a seasonal breeder and a natural model for autoimmunity. Northern blot analysis detected 2.8- and a 3.7-kb Cx43 mRNA bands in seminiferous tubule-enriched fractions. Cx43 mRNA increased in seminiferous tubule-enriched fractions throughout development and then seasonally with the completion of spermatogenesis. Cx43 protein levels increased transiently during the colonization of the tubules by the early-stage spermatocytes. Cx43 phosphorylated (PCx43) and nonphosphorylated (NPCx43) in Ser368 decreased during the periods of completion of meiosis and Sertoli cell differentiation, while Cx43 mRNA remained elevated throughout. PCx43 labeled chiefly the plasma membrane except by stage VII when vesicles were also labeled in Sertoli cells. Vesicles and lysosomes in Sertoli cells and the Golgi apparatus in the round spermatids were NPCx43 positive. A decrease in Cx43 gene expression was matched by a Cx43 protein increase in the early, not the late, phase of AIO. Total Cx43 and PCx43 decreased with the advance of orchitis. The study makes a novel finding of gap junctions connecting germ cells. The data indicate that Cx43 protein expression and phosphorylation in Ser368 are stage-specific events that may locally influence the acquisition of meiotic competence and the Sertoli cell differentiation in normal testis. AIO modifies Cx43 levels, suggesting changes in Cx43-mediated intercommunication and spermatogenic activity in response to cytokines imbalances in Sertoli cells.

scholarly journals Ischemia Alters the Expression of Connexins in the Aged Human Brain

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Taizen Nakase ◽  
Tetsuya Maeda ◽  
Yasuji Yoshida ◽  
Ken Nagata
Keyword(s):  
Gap Junctions ◽  
Connexin 43 ◽  
Immunohistochemical Analysis ◽  
Analysis Data ◽  
Computer Assisted ◽  
Ischemic Insult ◽  
Cx43 Expression ◽  
Neuronal Marker ◽  
Neuronal Markers ◽  
Human Stroke

Although the function of astrocytic gap junctions under ischemia is still under debate, increased expression of connexin 43 (Cx43) has been observed in ischemic brain lesions, suggesting that astrocytic gap junctions could provide neuronal protection against ischemic insult. Moreover, different connexin subtypes may play different roles in pathological conditions. We used immunohistochemical analysis to investigate alterations in the expression of connexin subtypes in human stroke brains. Seven samples, sectioned after brain embolic stroke, were used for the analysis. Data, evaluated semiquantitatively by computer-assisted densitometry, was compared between the intact hemisphere and ischemic lesions. The results showed that the coexpression of Cx32 and Cx45 with neuronal markers was significantly increased in ischemic lesions. Cx43 expression was significantly increased in the colocalization with astrocytes and relatively increased in the colocalization with neuronal marker in ischemic lesions. Therefore, Cx32, Cx43, and Cx45 may respond differently to ischemic insult in terms of neuroprotection.

Expression of connexin 43 (Cx43) is critical for normal hematopoiesis

Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 917-924 ◽  
Author(s):  
Encarnacion Montecino-Rodriguez ◽  
Hyosuk Leathers ◽  
Kenneth Dorshkind
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Blood Cell ◽  
Gap Junctions ◽  
Connexin 43 ◽  
Cell Formation ◽  
Cx43 Expression ◽  
Hematopoietic System ◽  
Blood Cell Formation

Abstract Gap junctions are intercellular channels, formed by individual structural units known as connexins (Cx), that allow the intercellular exchange of various messenger molecules. The finding that numbers of Cx43-type gap junctions in bone marrow are elevated during establishment and regeneration of the hematopoietic system has led to the hypothesis that expression of Cx43 is critical during the initiation of blood cell formation. To test this hypothesis, lymphoid and myeloid development were examined in mice with a targeted disruption of the gene encoding Cx43. Because Cx43−/− mice die perinatally, initial analyses were performed on Cx43−/−, Cx43+/−, and Cx43+/+ embryos and newborns. The data indicate that lack of Cx43 expression during embryogenesis compromises the terminal stages of primary T and B lymphopoiesis. Cx43−/− embryos and neonates had a reduced frequency of CD4+ and T-cell receptor-expressing thymocytes and surface IgM+cells compared to their Cx43+/+ littermates. Surprisingly, Cx43+/− embryos/neonates also showed defects in B- and T-cell development similar to those observed in Cx43−/− littermates, but their hematopoietic system was normal at 4 weeks of age. However, the regeneration of lymphoid and myeloid cells was severely impaired in the Cx43+/− mice after cytoablative treatment. Taken together, these data indicate that loss of a single Cx43 allele can affect blood cell formation. Finally, the results of reciprocal bone marrow transplants between Cx43+/+ and Cx43+/− mice and examination of hematopoietic progenitors and stromal cells in vitro indicates that the primary effects of Cx43 are mediated through its expression in the hematopoietic microenvironment.

scholarly journals Cx43 and Associated Cell Signaling Pathways Regulate Tunneling Nanotubes in Breast Cancer Cells

Cancers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2798
Author(s):  
Alexander Tishchenko ◽  
Daniel D. Azorín ◽  
Laia Vidal-Brime ◽  
María José Muñoz ◽  
Pol Jiménez Arenas ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gap Junctions ◽  
Small Molecules ◽  
Cancer Cells ◽  
Signaling Pathways ◽  
Connexin 43 ◽  
Breast Cancer Cell Lines ◽  
Tunneling Nanotubes ◽  
Cx43 Expression ◽  
Cancer Signaling

Connexin 43 (Cx43) forms gap junctions that mediate the direct intercellular diffusion of ions and small molecules between adjacent cells. Cx43 displays both pro- and anti-tumorigenic properties, but the mechanisms underlying these characteristics are not fully understood. Tunneling nanotubes (TNTs) are long and thin membrane projections that connect cells, facilitating the exchange of not only small molecules, but also larger proteins, organelles, bacteria, and viruses. Typically, TNTs exhibit increased formation under conditions of cellular stress and are more prominent in cancer cells, where they are generally thought to be pro-metastatic and to provide growth and survival advantages. Cx43 has been described in TNTs, where it is thought to regulate small molecule diffusion through gap junctions. Here, we developed a high-fidelity CRISPR/Cas9 system to knockout (KO) Cx43. We found that the loss of Cx43 expression was associated with significantly reduced TNT length and number in breast cancer cell lines. Notably, secreted factors present in conditioned medium stimulated TNTs more potently when derived from Cx43-expressing cells than from KO cells. Moreover, TNT formation was significantly induced by the inhibition of several key cancer signaling pathways that both regulate Cx43 and are regulated by Cx43, including RhoA kinase (ROCK), protein kinase A (PKA), focal adhesion kinase (FAK), and p38. Intriguingly, the drug-induced stimulation of TNTs was more potent in Cx43 KO cells than in wild-type (WT) cells. In conclusion, this work describes a novel non-canonical role for Cx43 in regulating TNTs, identifies key cancer signaling pathways that regulate TNTs in this setting, and provides mechanistic insight into a pro-tumorigenic role of Cx43 in cancer.

scholarly journals Knowledge and Attitude of Pregnant Women toward Elective Cesarean Section in Saudi Arabia

2019 ◽  
Vol 09 (02) ◽  
pp. 199-208
Author(s):  
Afaf Abdul-Jabar Al Sulamy ◽  
Shadia A. Yousuf ◽  
Hala Ahmed Thabet
Keyword(s):  
Saudi Arabia ◽  
Cesarean Section ◽  
Pregnant Women ◽  
Elective Cesarean Section ◽  
Elective Cesarean ◽  
Knowledge And Attitude

scholarly journals Maternal Serum Melatonin Increases During Pregnancy and Falls Immediately After Delivery Implicating the Placenta as a Major Source of Melatonin

2021 ◽  
Vol 11 ◽  
Author(s):  
Haroon Ejaz ◽  
Juliana K. Figaro ◽  
Andrea M. F. Woolner ◽  
Bensita M. V. Thottakam ◽  
Helen F. Galley
Keyword(s):  
Pregnant Women ◽  
Physiological Role ◽  
Placental Tissue ◽  
Serum Levels ◽  
Normal Pregnancy ◽  
Maternal Serum ◽  
Major Metabolite ◽  
Elective Cesarean Section ◽  
Elective Cesarean ◽  
In Pregnancy

Melatonin is a neuroendocrine hormone which regulates circadian rhythm and is also an antioxidant. The role of melatonin in pregnancy is emerging. The enzymes needed for endogenous synthesis of melatonin have been identified in the placenta, although the contribution to circulating maternal melatonin in normal pregnancy is unclear. This work aimed to determine serum levels of melatonin and its major metabolite 6-hydroxymelatonin sulfate (6-OHMS) in normal pregnant women during each trimester of pregnancy, and immediately after delivery. Blood samples were obtained from a cohort of healthy pregnant women during each trimester of pregnancy (n = 26), from women scheduled for elective Cesarean section (CS) before and after delivery (n = 15), along with placental samples, and from healthy non-pregnant women as controls (n = 30). Melatonin and its major metabolite, 6-OHMS, were measured using enzyme immunoassay. Levels of serum melatonin were significantly higher during pregnancy than in non-pregnant women (P = 0.025) and increased throughout pregnancy (P < 0.0001). In women undergoing CS, serum melatonin decreased markedly 24 h after delivery (P = 0.0013). Similar results were seen for serum levels of 6-OHMS, and placental tissue 6-OHMS levels correlated with week of gestation at delivery (p = 0.018). In summary, maternal melatonin production is higher in pregnant than in non-pregnant women, increases significantly during pregnancy with highest levels in the third trimester, and decreases abruptly after delivery. These results suggest that the placenta is a major source of melatonin and supports a physiological role for melatonin in pregnancy.

scholarly journals Sympathetic Overactivity in CKD Disrupts Buffering of Neurotransmission by Endothelium-Derived Hyperpolarizing Factor and Enhances Vasoconstriction

2020 ◽  
Vol 31 (10) ◽  
pp. 2312-2325
Author(s):  
Wei Cao ◽  
Liling Wu ◽  
Xiaodong Zhang ◽  
Jing Zhou ◽  
Jian Wang ◽  
...  
Keyword(s):  
Gap Junction ◽  
Vascular Resistance ◽  
Connexin 43 ◽  
Structural Changes ◽  
Ex Vivo ◽  
Resistance Arteries ◽  
Cx43 Expression ◽  
Neurovascular Transmission

BackgroundHypertension commonly complicates CKD. Vascular smooth muscle cells (VSMCs) of resistance arteries receive signals from the sympathetic nervous system that induce an endothelial cell (EC)–dependent anticontractile response that moderates vasoconstriction. However, the specific role of this pathway in the enhanced vasoconstriction in CKD is unknown.MethodsA mouse model of CKD hypertension generated with 5/6-nephrectomy (5/6Nx) was used to investigate the hypothesis that an impaired anticontractile mechanism enhances sympathetic vasoconstriction. In vivo, ex vivo (isolated mesenteric resistance arteries), and in vitro (VSMC and EC coculture) models demonstrated neurovascular transmission and its contribution to vascular resistance.ResultsBy 4 weeks, 5/6Nx mice (versus sham) had augmented increases in mesenteric vascular resistance and mean arterial pressure with carotid artery occlusion, accompanied by decreased connexin 43 (Cx43) expression at myoendothelial junctions (MEJs), impaired gap junction function, decreased EC-dependent hyperpolarization (EDH), and enhanced contractions. Exposure of VSMCs to NE for 24 hours in a vascular cell coculture decreased MEJ Cx43 expression and MEJ gap junction function. These changes preceded vascular structural changes evident only at week 8. Inhibition of central sympathetic outflow or transfection of Cx43 normalized neurovascular transmission and vasoconstriction in 5/6Nx mice.Conclusions5/6Nx mice have enhanced neurovascular transmission and vasoconstriction from an impaired EDH anticontractile component before vascular structural changes. These neurovascular changes depend on an enhanced sympathetic discharge that impairs the expression of Cx43 in gap junctions at MEJs, thereby interrupting EDH responses that normally moderate vascular tone. Dysregulation of neurovascular transmission may contribute to the development of hypertension in CKD.

The mechanism of EDHF-mediated responses in subcutaneous small arteries from healthy pregnant women

2004 ◽  
Vol 286 (6) ◽  
pp. R1102-R1109 ◽  
Author(s):  
Leonid Luksha ◽  
Henry Nisell ◽  
Karolina Kublickiene
Keyword(s):  
Gap Junctions ◽  
Pregnant Women ◽  
Subcutaneous Fat ◽  
Specific Inhibitor ◽  
Normal Pregnancy ◽  
Induced Responses ◽  
Response Curves ◽  
Small Arteries ◽  
Isolated Arteries ◽  
Cytochrome P 450

We studied the importance of endothelium-derived hyperpolarizing factor (EDHF) vs. nitric oxide (NO) and prostacyclin (PGI2) in bradykinin (BK)-induced relaxation in isolated small subcutaneous arteries from normal pregnant women. We also explored the contribution of cytochrome P-450 (CYP450) product of arachidonic acid (AA) metabolism, hydrogen peroxide (H2O2), and gap junctions that have been suggested to be involved in EDHF-mediated responses. Isolated arteries obtained from subcutaneous fat biopsies of normal pregnant women ( n = 30) undergoing planned cesarean section were mounted in a wire-myography system. In norepinephrine-constricted vessels, incubation with NG-nitro-l-arginine methyl ester (l-NAME) resulted in a significant reduction in relaxation to BK. Simultaneous incubation with l-NAME and indomethacin failed to modify this response further. BK-mediated dilatation in the presence of K+-modified solution was decreased to similar level as obtained after incubation with l-NAME. Incubation with l-NAME abolished BK-induced responses in K+-modified solution. Sulfaphenazole, a specific inhibitor of CYP450 epoxygenase, and catalase (an enzyme that decomposes H2O2) did not affect the EDHF-mediated relaxation because concentration-response curves to BK were similar in arteries after incubation with l-NAME vs. l-NAME + sulfaphenazole and l-NAME + catalase. The inhibitor of gap junctions, 18α-glycyrrhetinic acid, significantly reduced BK-mediated relaxation both without and with incubation with l-NAME. We found that both NO and EDHF, but not PGI2, are involved in the endothelium-dependent dilatation to BK. BK-induced relaxation is almost equally mediated by NO and EDHF. CYP450 epoxygenase metabolites of AA or H2O2 do not account for EDHF-mediated response; however, gap junctions are involved in the EDHF-mediated responses to BK in subcutaneous small arteries in normal pregnancy.

Sign in / Sign up

Export Citation Format

Share Document