Related Experiment Video
Updated: Apr 28, 2026
Alternate Immersion in Glucose to Produce Prolonged Hyperglycemia in Zebrafish
Published on: May 5, 2021
High glucose alters Cx43 expression and gap junction intercellular communication in retinal Müller cells: promotes
Tetsuya Muto1, Thomas Tien1, Dongjoon Kim1
1Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States.
Purpose:
To investigate whether high glucose (HG) alters connexin 43 (Cx43) expression and gap junction intercellular communication (GJIC) activity in retinal Müller cells, and promotes Müller cell and pericyte loss.
Methods:
Retinal Müller cells (rMC-1) and cocultures of rMC-1 and retinal pericytes were grown in normal (N) or HG (30 mM glucose) medium. Additionally, rMC-1 transfected with Cx43 small interfering RNA (siRNA) were grown as cocultures with pericytes, and rMC-1 transfected with Cx43 plasmid were grown in HG. Expression of Cx43 was determined by Western blotting and immunostaining and GJIC was assessed by scrape-loading dye transfer (SLDT) technique. Apoptosis was analyzed by TUNEL or differential staining assay, and Akt activation by assessing Akt phosphorylation.
Results:
In monocultures of rMC-1 and cocultures of rMC-1 and pericytes, Cx43 protein level, number of Cx43 plaques, GJIC, and Akt phosphorylation were significantly reduced in HG medium. Number of TUNEL-positive cells was also significantly increased in rMC-1 monocultures and in rMC-1 and pericyte cocultures grown in HG medium. Importantly, when rMC-1 transfected with Cx43 siRNA were grown as cocultures with pericytes, a significant decrease in GJIC, and increase in TUNEL-positive cells was observed, concomitant with decreased Akt phosphorylation. Upregulation of Cx43 rescued rMC-1 from HG-induced apoptosis.
Conclusions:
Gap junction communication between Müller cells and pericytes is essential for their survival. Downregulation of Cx43 that is HG induced and impairment of GJIC activity in Müller cells contributes to loss of glial and vascular cells associated with the pathogenesis of diabetic retinopathy.
Insights
High glucose reduces connexin 43 (Cx43) and gap junction communication in retinal cells, leading to cell loss. Restoring Cx43 protects against this damage, crucial for diabetic retinopathy.
Area of Science:
- Ophthalmology
- Cell Biology
- Diabetic Retinopathy Research
Background:
- Diabetic retinopathy involves Müller cell and pericyte loss.
- The role of connexin 43 (Cx43) and gap junction intercellular communication (GJIC) in this process is unclear.
Purpose of the Study:
- To investigate if high glucose (HG) affects Cx43 expression and GJIC in retinal Müller cells.
- To determine if HG promotes Müller cell and pericyte loss.
Main Methods:
- Cultured retinal Müller cells (rMC-1) and pericytes in normal and HG conditions.
- Assessed Cx43 expression, GJIC activity, and apoptosis.
- Utilized Cx43 siRNA and plasmid transfections to manipulate Cx43 levels.
Main Results:
- HG significantly reduced Cx43 protein, GJIC, and Akt phosphorylation in Müller cells and cocultures.
- HG increased apoptosis in both cell types.
- Cx43 downregulation exacerbated HG-induced cell death, while upregulation conferred protection.
Conclusions:
- Impaired GJIC due to HG-induced Cx43 downregulation contributes to Müller cell and pericyte loss.
- This dysfunction is a key factor in diabetic retinopathy pathogenesis.
- Maintaining GJIC is vital for retinal cell survival in diabetes.
Related Concept Videos
01:26Glucose Absorption Into the Small Intestine
01:02Glucose Homeostasis: Regulation of Blood Glucose
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
01:16Hormones Regulating Blood Glucose
In addition to accelerating glucose uptake and utilization, insulin has...