scholarly journals Connexin 26 and Connexin 43 in Canine Mammary Carcinoma

2019 ◽  
Vol 6 (4) ◽  
pp. 101 ◽  
Author(s):  
Savannah Luu ◽  
Cynthia Bell ◽  
Sarah Schneider ◽  
Thu Annelise Nguyen
Keyword(s):  
Breast Cancer ◽  
Gap Junction ◽  
Intercellular Communication ◽  
Mammary Carcinoma ◽  
Connexin 43 ◽  
Mammary Tumors ◽  
Mammary Cells ◽  
Cx43 Expression ◽  
Canine Mammary Carcinoma

Incidence of canine mammary carcinoma is two times higher than the rate of human breast cancer. Mammary tumors are the most common type of cancer in intact female dogs and account for about half of all neoplasms in these dogs. Well-established models of breast cancer have shown that neoplastic cells often have a loss of intercellular communication, particularly gap junction proteins. Thus, the objective of this study is to explore the aspect of gap junction intercellular communication in canine mammary carcinoma, non-cancerous (CMEC) and cancerous (CMT12, CMT27, and CF41.Mg) cells, and patient-derived tumors. Both non-cancerous and cancerous mammary cells express connexins 26 and 43 using immunofluorescence; however, the level of expression is significantly different in quantitative analysis using western blot in which connexin 43 in both CMT12 and CMT27 is significantly decreased compared to CMEC. Furthermore, a decrease of gap junction capacity in CMT12 and CMT27 was observed compared to CMEC. Immunostaining of CMT27-xenograft tumors revealed positive Cx26 and negative Cx43 expression. Similarly, immunostaining of spontaneous canine mammary tumors revealed that Cx26 is present in all tumors while Cx43 is present in 25% of tumors. Overall, the study provides for the first time that a differential pattern of connexin expression exists between non-cancerous and cancerous mammary cells in dogs. This study will pave the path for further in vitro work of connexins in comparative canine models and possibly allow for novel therapeutics to be developed.

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.

Human Marrow Stromal Cells Enhance Connexin43 Gap Junction Intercellular Communication in Cultured Astrocytes

2005 ◽  
Vol 14 (2-3) ◽  
pp. 109-117 ◽  
Author(s):  
Qi Gao ◽  
Mark Katakowski ◽  
Xiaoguang Chen ◽  
Yi Li ◽  
Michael Chopp
Keyword(s):  
Gap Junction ◽  
Intercellular Communication ◽  
Stromal Cells ◽  
Connexin 43 ◽  
Marrow Stromal Cells ◽  
Dye Transfer ◽  
Cx43 Expression ◽  
Soluble Factors ◽  
Functional Benefit ◽  
Gap Junction Intercellular Communication

Human marrow stromal cells (hMSCs) provide functional benefit in rats subjected to stroke. Astrocytes are coupled into a cellular network via gap junction channels, predominantly composed of connexin-43 (Cx43) proteins. Astrocytes are believed to play a vital role in neuroprotection by providing energy substrates to neurons and by regulating the concentrations of K+ and neurotransmitters via gap junctions. We therefore investigated the effect of factors secreted by hMSCs on gap junction intercellular communication (GJIC), expression of Cx43, and phosphorylation of Cx43 in an astrocyte cell culture system. Exposing rat cortical astrocytes to various concentrations of hMSC conditioned medium, we demonstrate that hMSCs produce soluble factors that significantly increase astrocytic GJIC, measured by the scrape-loading dye transfer method. Immunohistochemistry and Western blot showed increased Cx43 expression concomitant with altered GJIC. As the PI3K/Akt signaling pathway has been demonstrated to alter gap junction expression and GJIC, we selectively blocked phosphoinositide 3-kinase (PI3K). Addition of the PI3K inhibitor LY294002 decreased GJIC and Cx43 expression in astrocytes. These inhibitory effects of LY294002 were countered by the addition of hMSC conditioned media. Furthermore, coculturing hMSCs with rat astrocytes increased astrocyte GJIC in a manner dependent upon the hMSC/astrocyte ratio. These findings demonstrate that hMSCs secrete soluble factors that increase GJIC of astrocytes through upregulation of Cx43, and indicate a mechanistic role for PI3K.

scholarly journals Implication of Connexin 43 as a Tumor Suppressor in Pathogenesis of Breast Cancer

2021 ◽  
Author(s):  
Rabiya Rashid ◽  
Shazia Ali ◽  
Mahboob-Ul-Hussain
Keyword(s):  
Breast Cancer ◽  
Gap Junction ◽  
Intercellular Communication ◽  
Connexin 43 ◽  
Global Public Health ◽  
Down Regulation ◽  
Public Health Burden ◽  
Functional Dynamics ◽  
Gap Junction Intercellular Communication ◽  
Tumor Types

Breast cancer (BC) is a global public health burden, constituting the highest cancer incidence in women worldwide. Connexins 43 proteins propagate intercellular communication, gap junction intercellular communication (GJIC), remarkably expressed in several tumor types including liver, prostate, and breast. This domain of Cx43 possesses functionally critical sites identical to those involved in gating of channel and phosphorylation sites for various kinases. However, the mechanism by which Cx43 down regulation occurs in breast cancer is far from clear. Several mechanisms like Cx43 promoter hyper-methylation or a cancer-specific reduction of Cx43 expression/trafficking by the modulation of various components of the Cx43 life cycle give the idea to be involved in the down regulation of Connexins in mammary glands, but irreversible mutational alterations have not yet been proved to be among them. Summarily, the efficacy or specificity of these drugs can be increased by a combinatory approach considering an effect on both the Connexins and their regulatory molecules. This chapter will summarize the knowledge about the connexins and gap junction activities in breast cancer highlighting the differential expression and functional dynamics of connexins in the pathogenesis of the disease.

scholarly journals The Specific Connexin 43–Inhibiting Peptide Gap26 Improved Alveolar Development of Neonatal Rats With Hyperoxia Exposure

2021 ◽  
Vol 12 ◽  
Author(s):  
Cai Qing ◽  
Zhao Xinyi ◽  
Yu Xuefei ◽  
Xue Xindong ◽  
Fu Jianhua
Keyword(s):  
Oxidative Stress ◽  
Intercellular Communication ◽  
Connexin 43 ◽  
Stress Signaling ◽  
Ros Production ◽  
Cx43 Expression ◽  
Alveolar Development ◽  
Hyperoxia Exposure

Bronchopulmonary dysplasia (BPD) is a common devastating pulmonary complication in preterm infants. Alveolar maldevelopment is the crucial pathological change of BPD highly associated with oxidative stress–mediated excessive apoptosis. Cellular injury can be propagated and amplified by gap junction (GJ)–mediated intercellular communication. Connexin 43 (Cx43) is the most ubiquitous and critical GJ protein. Gap26 is a specific Cx43 mimic peptide, playing as a Cx43-GJ inhibitor. We hypothesized that Cx43-GJ was involved in alveolar maldevelopment of BPD via amplifying oxidative stress signaling and inducing excessive apoptosis. Neonatal Sprague Dawley rats were kept in either normoxia (21% O2) or hyperoxia (85% O2) continuously from postnatal day (PN) 1 to 14 in the presence or absence of Gap26. Moreover, RLE-6TN cells (type II alveolar epithelial cells of rats) were cultured in vitro under normoxia (21% O2) or hyperoxia (85% O2). RLE-6TN cells were treated by N-acetyl cysteine (NAC) (a kind of reactive oxygen species (ROS) scavenger) or Gap26. Morphological properties of lung tissue are detected. Markers associated with Cx43 expression, ROS production, the activity of the ASK1-JNK/p38 signaling pathway, and apoptotic level are detected in vivo and in vitro, respectively. In vitro, the ability of GJ-mediated intercellular communication was examined by dye-coupling assay. In vitro, our results demonstrated ROS increased Cx43 expression and GJ-mediated intercellular communication and Gap26 treatment decreased ROS production, inhibited ASK1-JNK/p38 signaling, and decreased apoptosis. In vivo, we found that hyperoxia exposure resulted in increased ROS production and Cx43 expression, activated ASK1-JNK/p38 signaling, and induced excessive apoptosis. However, Gap26 treatment reversed these changes, thus improving alveolar development in neonatal rats with hyperoxia exposure. In summary, oxidative stress increased Cx43 expression and Cx43-GJ–mediated intercellular communication. And Cx43-GJ–mediated intercellular communication amplified oxidative stress signaling, inducing excessive apoptosis via the ASK1-JNK/p38 signaling pathway. The specific connexin 43–inhibiting peptide Gap26 was a novel therapeutic strategy to improve the alveolar development of BPD.

scholarly journals The connexin 43/ZO-1 complex regulates cerebral endothelial F-actin architecture and migration

2015 ◽  
Vol 309 (9) ◽  
pp. C600-C607 ◽  
Author(s):  
Cheng-Hung Chen ◽  
Jamie N. Mayo ◽  
Robert G. Gourdie ◽  
Scott R. Johnstone ◽  
Brant E. Isakson ◽  
...  
Keyword(s):  
Wound Healing ◽  
Endothelial Cell ◽  
Actin Cytoskeleton ◽  
Gap Junction ◽  
Connexin 43 ◽  
Cell Spreading ◽  
Endothelial Cell Migration ◽  
Cx43 Expression ◽  
Junction Protein

Endothelial cell migration is a fundamental process during angiogenesis and, therefore, a point of intervention for therapeutic strategies aimed at controlling pathologies involving blood vessel growth. We sought to determine the role of the gap junction protein connexin 43 (Cx43) in key features of angiogenesis in the central nervous system. We used an in vitro model to test the hypothesis that a complex of interacting proteins, including Cx43 and zonula occludens-1 (ZO-1), regulates the migratory behavior of cerebral endothelium. With knockdown and overexpression experiments, we demonstrate that the rate of healing following scrape-wounding of endothelium is regulated by the level of Cx43 protein expression. The effects on cell motility and proliferation were independent of gap junction communication as cells were sensitive to altered Cx43 expression in single plated cells. Coupling of Cx43/ZO-1 critically regulates this process as demonstrated with the use of a Cx43 α-carboxy terminus 1 peptide mimetic (αCT1) and overexpression of a mutant ZO-1 with the Cx43-binding PDZ2 domain deleted. Disrupting the Cx43/ZO-1 complex with these treatments resulted in collapse of the organized F-actin cytoskeleton and the appearance of actin nodes. Preincubation with the myosin 2 inhibitors blebbistatin or Y-27632 disrupted the Cx43/ZO-1 complex and inhibited cell spreading at the leading edge of migration. Cells studied individually in time-lapse open field locomotion assays wandered less when Cx43/ZO-1 interaction was disrupted without significant change in speed, suggesting that faster wound healing is a product of linearized migration. In contrast to the breakdown of F-actin architecture, microtubule architecture was not obviously affected by treatments. This study provides new insight into the fundamental regulatory mechanisms of cerebral endothelial cell locomotion. Cx43 tethers the F-actin cytoskeleton through a ZO-1 linker and supports cell spreading and exploration during locomotion. Here, we demonstrate that releasing this actin-coupled tether shifts the balance of directional migration control to a more linear movement that enhances the rate of wound healing.

scholarly journals High-Glucose-Induced Rab20 Upregulation Disrupts Gap Junction Intercellular Communication and Promotes Apoptosis in Retinal Endothelial and Müller Cells: Implications for Diabetic Retinopathy

2020 ◽  
Vol 9 (11) ◽  
pp. 3710
Author(s):  
Dongjoon Kim ◽  
Casey Stottrup Lewis ◽  
Vijay P. Sarthy ◽  
Sayon Roy
Keyword(s):  
Diabetic Retinopathy ◽  
Gap Junction ◽  
Intercellular Communication ◽  
High Glucose ◽  
Connexin 43 ◽  
Müller Cells ◽  
Muller Cells ◽  
Dye Transfer ◽  
Cx43 Expression ◽  
Gap Junction Intercellular Communication

To investigate whether high glucose (HG) alters Rab20 expression and compromises gap junction intercellular communication (GJIC) and cell survival, retinal cells were studied for altered intracellular trafficking of connexin 43 (Cx43). Retinal endothelial cells (RRECs) and retinal Müller cells (rMCs) were grown in normal (N; 5 mM glucose) or HG (30 mM glucose) medium for seven days. In parallel, cells grown in HG medium were transfected with either Rab20 siRNA or scrambled siRNA as a control. Rab20 and Cx43 expression and their localization and distribution were assessed using Western Blot and immunostaining, respectively. Changes in GJIC activity were assessed using scrape load dye transfer, and apoptosis was identified using differential dye staining assay. In RRECs or rMCs grown in HG medium, Rab20 expression was significantly increased concomitant with a decreased number of Cx43 plaques. Importantly, a significant increase in the number of Cx43 plaques and GJIC activity was observed in cells transfected with Rab20 siRNA. Additionally, Rab20 downregulation inhibited HG-induced apoptosis in RRECs and rMCs. Results indicate HG-mediated Rab20 upregulation decreases Cx43 localization at the cell surface, resulting in compromised GJIC activity. Reducing Rab20 expression could be a useful strategy in preventing HG-induced vascular and Müller cell death associated with diabetic retinopathy.

Phosphorylation of connexin 43 induced by traumatic brain injury promotes exosome release

2018 ◽  
Vol 119 (1) ◽  
pp. 305-311 ◽  
Author(s):  
Wei Chen ◽  
Yijun Guo ◽  
Wenjin Yang ◽  
Lei Chen ◽  
Dabin Ren ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Gap Junction ◽  
Connexin 43 ◽  
Hippocampal Slices ◽  
Long Term Potentiation ◽  
Cx43 Expression ◽  
Term Potentiation ◽  
Junction Protein

Traumatic brain injury (TBI) caused by the external force leads to the neuronal dysfunction and even death. TBI has been reported to significantly increase the phosphorylation of glial gap junction protein connexin 43 (Cx43), which in turn propagates damages into surrounding brain tissues. However, the neuroprotective and anti-apoptosis effects of glia-derived exosomes have also been implicated in recent studies. Therefore, we detected whether TBI-induced phosphorylation of Cx43 would promote exosome release in rat brain. To generate TBI model, adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury. Phosphorylated Cx43 protein levels and exosome activities were quantified using Western blot analysis following TBI. Long-term potentiation (LTP) was also tested in rat hippocampal slices. TBI significantly increased the phosphorylated Cx43 and exosome markers expression in rat ipsilateral hippocampus, but not cortex. Blocking the activity of Cx43 or ERK, but not JNK, significantly suppressed TBI-induced exosome release in hippocampus. Furthermore, TBI significantly inhibited the induction of LTP in hippocampal slices, which could be partially but significantly restored by pretreatment with exosomes. The results imply that TBI-activated Cx43 could mediate a nociceptive effect by propagating the brain damages, as well as a neuroprotective effect by promoting exosome release. NEW & NOTEWORTHY We have demonstrated in rat traumatic brain injury (TBI) models that both phosphorylated connexin 43 (p-Cx43) expression and exosome release were elevated in the hippocampus following TBI. The promoted exosome release depends on the phosphorylation of Cx43 and requires ERK signaling activation. Exosome treatment could partially restore the attenuated long-term potentiation. Our results provide new insight for future therapeutic direction on the functional recovery of TBI by promoting p-Cx43-dependent exosome release but limiting the gap junction-mediated bystander effect.

Involvement of Nestin in the Progression of Canine Mammary Carcinoma

2021 ◽  
pp. 030098582110186
Author(s):  
Hisashi Yoshimura ◽  
Maiko Moriya ◽  
Ayaka Yoshida ◽  
Masami Yamamoto ◽  
Yukino Machida ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Mammary Carcinoma ◽  
Mammary Tumors ◽  
Carcinoma Cells ◽  
Nestin Expression ◽  
Mammary Carcinomas ◽  
Canine Mammary Carcinoma ◽  
Canine Mammary Tumors ◽  
Mammary Carcinoma Cells ◽  
Luminal Epithelial Cells

Nestin, a class VI intermediate filament protein, is known to be expressed in various types of human neoplasms, including breast cancer, and is associated with their progression. However, its expression and role in canine mammary tumors remain unknown. We analyzed nestin expression in canine mammary tumors using in situ hybridization and immunohistochemistry. We also investigated its role in a canine mammary carcinoma cell line using RNA interference. Nestin expression was not observed in luminal epithelial cells of any of the 62 cases of benign mammary lesions examined, although myoepithelial cells showed its expression in most cases. In 16/50 (32%) primary mammary carcinomas and 6/15 (40%) metastases of mammary carcinomas, cytoplasmic nestin expression was detected in luminal epithelial cells. In luminal cells of primary mammary carcinomas, its expression was positively related to several pathological parameters that indicate high-grade malignancy, including histological grading ( P < .01), vascular/lymphatic invasion ( P < .01), Ki-67 index ( P < .01), and metastasis ( P < .05). Immunohistochemistry revealed that nestin expression was related to vimentin expression in mammary carcinomas ( P < .01). This relationship was confirmed using reverse transcription-quantitative polymerase chain reaction using 9 cell lines derived from canine mammary carcinoma ( P < .01). Finally, nestin knockdown in canine mammary carcinoma cells using small interfering RNA inhibited cell proliferation and migration based on WST-8, Boyden chamber, and cell-tracking assays. These findings suggest that nestin may at least partially mediate these behaviors of canine mammary carcinoma cells.

SDF-1α regulation in breast cancer cells contacting bone marrow stroma is critical for normal hematopoiesis

Blood ◽  
2006 ◽  
Vol 108 (10) ◽  
pp. 3245-3252 ◽  
Author(s):  
Anabella L. Moharita ◽  
Marcelo Taborga ◽  
Kelly E. Corcoran ◽  
Margarette Bryan ◽  
Prem S. Patel ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Bone Marrow ◽  
Cancer Cells ◽  
Connexin 43 ◽  
Breast Cancer Cells ◽  
Critical Role ◽  
Contact Inhibition ◽  
Enzyme Linked Immunosorbent Assay ◽  
Hematopoietic Regulation

Abstract Breast cancer cells (BCCs) show preference for the bone marrow (BM). An animal model showed 2 populations of BCCs in the BM with regard to their cycling states. An in vitro model of early BC entry into BM showed normal hematopoiesis. Here, we show a critical role for BCC-derived SDF-1α in hematopoietic regulation. The studies used a coculture of BM stroma and BCCs (cell lines and stage II BCCs). Northern blots and enzyme-linked immunosorbent assay (ELISA) showed gradual decreases in SDF-1α production in BCCs as they contact BM stroma, indicating partial microenvironmental effects caused by stroma on the BCCs. SDF-1 knock-down BCCs and increased exogenous SDF-1α prevented contact inhibition between BCCs and BM stroma. Contact inhibition was restored with low SDF-1α levels. Long-term culture-initiating assays with CD34+/CD38–/Lin– showed normal hematopoiesis provided that SDF-1α levels were reduced in BCCs. Gap junctions (connexin-43 [CX-43]) were formed between BCCs and BM stroma, with concomitant interaction between CD34+/CD38–/Lin– and BM stroma but not with the neighboring BCCs. In summary, SDF-1α levels are reduced in BCCs that contact BM stroma. The low levels of SDF-1α in BCCs regulate interactions between BM stroma and hematopoietic progenitors, consequently facilitating normal hematopoiesis.

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