High Glucose Alters Connexin 43 Expression and Gap Junction Intercellular Communication Activity in Retinal Pericytes

2003 ◽  
Vol 44 (12) ◽  
pp. 5376 ◽  
Author(s):  
An-Fei Li ◽  
Tsuyoshi Sato ◽  
Robert Haimovici ◽  
Tamami Okamoto ◽  
Sayon Roy
2020 ◽  
Vol 9 (11) ◽  
pp. 3710
Author(s):  
Dongjoon Kim ◽  
Casey Stottrup Lewis ◽  
Vijay P. Sarthy ◽  
Sayon Roy

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.


2015 ◽  
Vol 43 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Teresa M. Ribeiro-Rodrigues ◽  
Steve Catarino ◽  
Maria J. Pinho ◽  
Paulo Pereira ◽  
Henrique Girao

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.


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