scholarly journals How miR-31-5p and miR-33a-5p Regulates SP1/CX43 Expression in Osteoarthritis Disease: Preliminary Insights

2021 ◽  
Vol 22 (5) ◽  
pp. 2471
Author(s):  
Viviana Costa ◽  
Marcello De Fine ◽  
Valeria Carina ◽  
Alice Conigliaro ◽  
Lavinia Raimondi ◽  
...  
Keyword(s):  
Joint Inflammation ◽  
Loss Of Function ◽  
Cx43 Expression ◽  
Cell Functions ◽  
Genes Expression ◽  
Junction Protein ◽  
Kellgren And Lawrence ◽  
Gap Junction Protein ◽  
The Common

Osteoarthritis (OA) is a degenerative bone disease that involved micro and macro-environment of joints. To date, there are no radical curative treatments for OA and novel therapies are mandatory. Recent evidence suggests the role of miRNAs in OA progression. In our previous studies, we demonstrated the role of miR-31-5p and miR-33a families in different bone regeneration signaling. Here, we investigated the role of miR-31-5p and miR-33a-5p in OA progression. A different expression of miR-31-5p and miR-33a-5p into osteoblasts and chondrocytes isolated from joint tissues of OA patients classified in based on different Kellgren and Lawrence (KL) grading was highlighted; and through a bioinformatic approach the common miRNAs target Specificity proteins (Sp1) were identified. Sp1 regulates the expression of gap junction protein Connexin43 (Cx43), which in OA drives the modification of (i) osteoblasts and chondrocytes genes expression, (ii) joint inflammation cytokines releases and (iii) cell functions. Concerning this, thanks to gain and loss of function studies, the possible role of Sp1 as a modulator of CX43 expression through miR-31-5p and miR-33a-5p action was also evaluated. Finally, we hypothesize that both miRNAs cooperate to modulate the expression of SP1 in osteoblasts and chondrocytes and interfering, consequently, with CX43 expression, and they might be further investigated as new possible biomarkers for OA.

scholarly journals Connexin43 and AMPK Have Essential Role in Resistance to Oxidative Stress Induced Necrosis

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Chunshan Zhao ◽  
Jinnv Fang ◽  
Chunguo Li ◽  
Min Zhang
Keyword(s):  
Oxidative Stress ◽  
Cell Damage ◽  
Ros Production ◽  
Cx43 Expression ◽  
Ampk Signaling ◽  
Junction Protein ◽  
A Cell ◽  
Intercellular Channels ◽  
Gap Junction Protein

Reactive oxygen species (ROS) induced oxidative stress leads to cell damage and neurological disorders in astrocytes. The gap junction protein connexin43 (Cx43) could form intercellular channels in astrocytes and the expression of Cx43 plays an important role in protecting the cells from damage. In the present study, we investigated the contribution of Cx43 to astrocytic necrosis induced by the ROS hydrogen peroxide (H2O2) and the mechanism by which AMPK was involved in this process. Fluorescence microscopy, flow cytometry, and western blot were used quantitatively and qualitatively to determine the cell apoptosis, necrosis, and protein expression. Lack of Cx43 expression or blockage of Cx43 channels resulted in increased H2O2-induced astrocytic necrosis, supporting a cell protective effect of functional Cx43 channels. Our data suggest that AMPK is important for Cx43-mediated ROS resistance. Inhibition of AMPK activation results in reduction of necrosis and ROS production. Taken together, our findings suggest that the role of Cx43 in response to H2O2stress is dependent on the activation of AMPK signaling pathways and regulates ROS production and cell necrosis.

scholarly journals Role of Gap Junction Protein Connexin43 in Astrogliosis Induced by Brain Injury

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e47311 ◽  
Author(s):  
Nicolas Theodoric ◽  
John F. Bechberger ◽  
Christian C. Naus ◽  
Wun-Chey Sin
Keyword(s):  
Brain Injury ◽  
Gap Junction ◽  
Junction Protein ◽  
Gap Junction Protein

scholarly journals MiRNA-143 mediates the proliferative signaling pathway of FSH and regulates estradiol production

2017 ◽  
Vol 234 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Li Zhang ◽  
XiaoXin Zhang ◽  
Xuejing Zhang ◽  
Yu Lu ◽  
Lei Li ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Loss Of Function ◽  
Cellular Processes ◽  
Cell Functions ◽  
Genes Expression ◽  
Underlying Mechanisms

MicroRNAs (MiRNAs) play important regulatory roles in many cellular processes. MiR-143 is highly enriched in the mouse ovary, but its roles and underlying mechanisms are not well understood. In the current study, we show that miR-143 is located in granulosa cells of primary, secondary and antral follicles. To explore the specific functions of miR-143, we transfected miR-143 inhibitor into primary cultured granulosa cells to study the loss of function of miR-143 and the results showed that miR-143 silencing significantly increased estradiol production and steroidogenesis-related gene expression. Moreover, our in vivo and in vitro studies showed that follicular stimulating hormone (FSH) significantly decreased miR-143 expression. This function of miR-143 is accomplished by its binding to the 3’-UTR of KRAS mRNA. Furthermore, our results demonstrated that miR-143 acts as a negative regulating molecule mediating the signaling pathway of FSH and affecting estradiol production by targeting KRAS. MiR-143 also negatively acts in regulating granulosa cells proliferation and cell cycle-related genes expression. These findings indicate that miR-143 plays vital roles in FSH-induced estradiol production and granulosa cell proliferation, providing a novel mechanism that involves miRNA in regulating granulosa cell functions.

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

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 117 ◽  
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.

Functional analysis of gap junctions in ovarian granulosa cells: distinct role for connexin43 in early stages of folliculogenesis

2003 ◽  
Vol 284 (4) ◽  
pp. C880-C887 ◽  
Author(s):  
Joanne E. I. Gittens ◽  
Abdul Amir Mhawi ◽  
Darcy Lidington ◽  
Yves Ouellette ◽  
Gerald M. Kidder
Keyword(s):  
Gap Junctions ◽  
Granulosa Cells ◽  
Significant Contribution ◽  
Ionic Current ◽  
Wild Type ◽  
Intercellular Coupling ◽  
Ovarian Granulosa Cells ◽  
Junction Protein ◽  
Gap Junction Protein

Ovarian granulosa cells are coupled via gap junctions containing connexin43 (Cx43 or α-1 connexin). In the absence of Cx43, granulosa cells stop growing in an early preantral stage. However, the fact that granulosa cells of mature follicles express multiple connexins complicated interpretation of this finding. The present experiments were designed to clarify the role of Cx43 vs. these other connexins in the earliest stages of folliculogenesis. Dye injection experiments revealed that granulosa cells from Cx43 knockout follicles are not coupled, and this was confirmed by ionic current injections. Furthermore, electron microscopy revealed that gap junctions are extremely rare in mutant granulosa cells. In contrast, mutant granulosa cells were able to form gap junctions with wild-type granulosa cells in a dye preloading assay. It was concluded that mutant granulosa cells contain a population of connexons, composed of an unidentified connexin, that do not normally contribute to gap junctions. Therefore, although Cx43 is not the only gap junction protein present in granulosa cells of early preantral follicles, it is the only one that makes a significant contribution to intercellular coupling.

scholarly journals Modulation of Rac1/PAK1/connexin43-Mediated ATP Release from Astrocytes Contributes to Retinal Ganglion Cell Survival in Experimental Glaucoma

2021 ◽  
Author(s):  
Guo-Li Zhao ◽  
Hong Zhou ◽  
Shu-Min Zhong ◽  
Han Zhou ◽  
Lin-Jie Xu ◽  
...  
Keyword(s):  
Gap Junction ◽  
Time Course ◽  
Atp Release ◽  
Conditional Knockout ◽  
Retinal Ganglion ◽  
Astrocyte Activation ◽  
Cx43 Expression ◽  
Junction Protein ◽  
Iop Elevation

Abstract Background: Connexin43 (Cx43) is one of major gap junction proteins in glial cells. Mutation in the gap junction protein alpha 1 gene of Cx43 has been detected in human glaucomatous retinas, suggestive of involvement of Cx43 in pathogenesis of glaucoma. However, the role of Cx43 in glaucoma has not been clearly elucidated. Methods: A mouse model of chronic ocular hypertension (COH) was produced by injecting magnetic microbeads into the eye anterior chamber. To explore the role of Rac1 in regulating Cx43 function, Rac1 conditional knockout in astrocytes was generated by subretinal injection of AAV-GFAP-Cre in Rac1flox/flox mice. The hemichannel activity was assayed by ethidium bromide uptake. The level and source of ATP were assayed by a commercial ATP assay kit, ATP sensors and removing microglia. Results: In this study, we showed that Cx43 were mainly expressed in retinal astrocytes. Intraocular pressure (IOP) elevation induced astrocyte activation, as evidenced by increased expressions of c-Fos and glial fibrillary acidic protein (GFAP), which results in downregulation of Cx43 and changes of Cx43 phosphorylation at Ser373 and Ser368 sites. In the optic nerve head of COH mice, Cx43 expression in Gap43 (an activity-dependent plasticity protein) positive astrocytes was reduced. In COH retinas, Rac1, a member of the Rho family, was activated, which was consistent with the decrease of Cx43 expression in a time course. Pharmacological inhibition of Rac1 inhibited the activity of its downstream molecule PAK1, and reversed the reduction of Cx43 expression and astrocyte activation induced by IOP elevation. Co-immunoprecipitation experiments further demonstrated the interactions between Cx43 and active Rac1 or p-PAK1. Inhibition of Rac1 or conditional knockout of Rac1 in macroglial cells increased the ATP release through Cx43 hemichannels in astrocytes of COH retinas. Additionally, Rac1 deletion in astrocytes upregulated the expression of adenosine A3 receptor in retinal ganglion cells (RGCs) and promoted RGC survival, at least at early stage of IOP elevation through activating adenosine receptors.Conclusions: Our results showed that Rac1 in astrocytes regulated glaucomatous RGC survival through Cx43-mediated ATP release. These findings suggest that modulation of Rac1/PAK1/Cx43 pathway in astrocytes may be a potential strategy of neuroprotection in glaucoma.

scholarly journals On the Role of the Gap Junction Protein Cx43 (GJA1) in Human Cardiac Malformations with Fallot-Pathology. A Study on Paediatric Cardiac Specimen

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e95344 ◽  
Author(s):  
Aida Salameh ◽  
Josphina Haunschild ◽  
Paul Bräuchle ◽  
Oliver Peim ◽  
Thomas Seidel ◽  
...  
Keyword(s):  
Gap Junction ◽  
Cardiac Malformations ◽  
Junction Protein ◽  
Gap Junction Protein

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

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.

scholarly journals Reduced expression of Cx43 attenuates ventricular remodeling after myocardial infarction via impaired TGF-β signaling

2010 ◽  
Vol 298 (2) ◽  
pp. H477-H487 ◽  
Author(s):  
Yan Zhang ◽  
Hongtao Wang ◽  
Attila Kovacs ◽  
Evelyn M. Kanter ◽  
Kathryn A. Yamada
Keyword(s):  
Myocardial Infarction ◽  
Wound Healing ◽  
Transforming Growth Factor ◽  
Ventricular Remodeling ◽  
Electrical Coupling ◽  
Downstream Signaling ◽  
Junction Protein ◽  
Infarct Healing ◽  
Gap Junction Protein

In addition to mediating cell-to-cell electrical coupling, gap junctions are important in tissue repair, wound healing, and scar formation. The expression and distribution of connexin43 (Cx43), the major gap junction protein expressed in the heart, are altered substantially after myocardial infarction (MI); however, the effects of Cx43 remodeling on wound healing and the attendant ventricular dysfunction are incompletely understood. Cx43-deficient and wild-type mice were subjected to proximal ligation of the anterior descending coronary artery and followed for 6 days or 4 wk to test the hypothesis that reduced expression of Cx43 influences wound healing, fibrosis, and ventricular remodeling after MI. We quantified the progression of infarct healing by measuring neutrophil expression, collagen content, and myofibroblast expression. We found significantly reduced transformation of fibroblasts to myofibroblasts at 6 days and significantly reduced collagen deposition both in the infarct at 6 days and at 4 wk in the noninfarcted region of Cx43-deficient mice. As expected, transforming growth factor (TGF)-β, a profibrotic cytokine, was dramatically upregulated in MI hearts, but its phosphorylated comediator (pSmad) was significantly downregulated in the nuclei of Cx43-deficient hearts post-MI, suggesting that downstream signaling of TGF-β is diminished substantially in Cx43-deficient hearts. This diminution in profibrotic TGF-β signaling resulted in the attenuation of adverse structural remodeling as assessed by echocardiography. These findings suggest that efforts to enhance the expression of Cx43 to maintain intercellular coupling or reduce susceptibility to arrhythmias should be met with caution until the role of Cx43 in infarct healing is fully understood.

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