Related Experiment Video
Updated: Mar 5, 2026
Retinal Explant of the Adult Mouse Retina as an Ex Vivo Model for Studying Retinal Neurovascular Diseases
Published on: December 9, 2022
The microRNA-7-mediated reduction in EPAC-1 contributes to vascular endothelial permeability and eNOS uncoupling in
Veronica Garcia-Morales1,2,3,4, Julian Friedrich2,3,4,5, Lysanne M Jorna4
1Group of Research in Pharmacology of Chronic Diseases (CDPHARMA), Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, 15782, Santiago de Compostela, Spain.
Aims:
To investigate the consequences of oxidative stress and hypoxia on EPAC-1 expression during retinopathy.
Methods:
Oxygen-induced retinopathy was induced in mice and EPAC-1 expression investigated by immunofluorescence. In silico analyses were used to identify a link between EPAC-1 expression and microRNA-7-5p in endothelial cells and confirmed by western blot analyses on cells expressing microRNA-7-5p. In vitro, endothelial cells were either incubated at 2% oxygen or transfected with microRNA-7-5p, and the effects of these treatments on EPAC-1 expression, endothelial hyperpermeability and NO production were assessed. In the Ins2Akita mouse model, levels of EPAC-1 expression as well as microRNA-7-5p were assessed by qPCR. Endothelial nitric oxide synthase was assessed by immunoblotting in the Ins2Akita model.
Results:
Hypoxia induces the expression of microRNA-7-5p that translationally inhibits the expression of EPAC-1 in endothelial cells, resulting in hyperpermeability and the loss of eNOS activity. Activation of EPAC-1 by the cAMP analogue 8-pCPT-2'-O-Me-cAMP reduced the sensitivity of EPAC-1 to oxidative stress and restored the endothelial permeability to baseline levels. Additionally, 8-pCPT-2'-O-Me-cAMP rescued eNOS activity and NO production. In mouse models of retinopathy, i.e., oxygen-induced retinopathy and the spontaneous diabetic heterozygous Ins2Akita mice, EPAC-1 levels are decreased which is associated with an increase in microRNA-7-5p expression and reduced eNOS activity.
Conclusion/Interpretation:
In retinopathy, EPAC-1 expression is decreased in a microRNA-7-mediated manner, contributing to endothelial dysfunction. Pharmacological activation of remnant EPAC-1 rescues endothelial function. Collectively, these data indicate that EPAC-1 resembles an efficacious and druggable target molecule for the amelioration of (diabetic) retinopathy.
Insights
Oxidative stress and hypoxia decrease EPAC-1 expression in retinopathy via microRNA-7-5p, causing endothelial dysfunction. Activating EPAC-1 can restore endothelial function and offers a potential therapeutic target for retinopathy.
Area of Science:
- Ocular vascular biology
- Endothelial cell function
- Retinopathy pathogenesis
Background:
- Retinopathy involves oxidative stress and hypoxia, leading to endothelial dysfunction.
- EPAC-1 (Exchange protein directly activated by cAMP 1) plays a role in endothelial cell regulation.
- MicroRNAs are implicated in regulating gene expression in disease states.
Purpose of the Study:
- To investigate the impact of oxidative stress and hypoxia on EPAC-1 expression in retinopathy.
- To elucidate the role of microRNA-7-5p in regulating EPAC-1 during retinopathy.
- To assess the therapeutic potential of EPAC-1 activation in retinopathy models.
Main Methods:
- Induction of oxygen-induced retinopathy in mice and assessment of EPAC-1 expression via immunofluorescence.
- In silico and in vitro analyses of microRNA-7-5p and EPAC-1 interactions in endothelial cells.
- Evaluation of EPAC-1, microRNA-7-5p, and eNOS in Ins2Akita diabetic retinopathy mouse models.
Main Results:
- Hypoxia upregulates microRNA-7-5p, inhibiting EPAC-1 translation and causing endothelial hyperpermeability and reduced eNOS activity.
- Pharmacological activation of EPAC-1 with 8-pCPT-2'-O-Me-cAMP mitigated oxidative stress effects, restored endothelial permeability, and rescued eNOS activity.
- Reduced EPAC-1 and increased microRNA-7-5p levels were observed in mouse models of retinopathy, correlating with decreased eNOS activity.
Conclusions:
- EPAC-1 downregulation, mediated by microRNA-7-5p, contributes to endothelial dysfunction in retinopathy.
- Pharmacological activation of remaining EPAC-1 effectively rescues endothelial function.
- EPAC-1 represents a promising, druggable target for treating (diabetic) retinopathy.
More Related Videos
12:28Quantification of Vascular Parameters in Whole Mount Retinas of Mice with Non-Proliferative and Proliferative Retinopathies
Published on: March 12, 2022
10:46Retinal Cryo-sections, Whole-Mounts, and Hypotonic Isolated Vasculature Preparations for Immunohistochemical Visualization of Microvascular Pericytes
Published on: October 7, 2018