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Updated: Apr 25, 2026
Quantification of Immunostained Caspase-9 in Retinal Tissue
Published on: July 25, 2022
Caspase-14 expression impairs retinal pigment epithelium barrier function: potential role in diabetic macular edema
Selina Beasley1, Mohamed El-Sherbiny2, Sylvia Megyerdi3
1Cellular Biology and Anatomy, Medical College of Georgia, Georgia Regents University (GRU), Augusta, GA 30912, USA ; Oral Biology/Anatomy, College of Dental Medicine, GRU, Augusta, GA 30912, USA ; Culver Vision Discovery Institute and Department of Ophthalmology, Medical College of Georgia, GRU, Augusta, GA 30912, USA.
Abstract:
We recently showed that caspase-14 is a novel molecule in retina with potential role in accelerated vascular cell death during diabetic retinopathy (DR). Here, we evaluated whether caspase-14 is implicated in retinal pigment epithelial cells (RPE) dysfunction under hyperglycemia. The impact of high glucose (HG, 30 mM D-glucose) on caspase-14 expression in human RPE (ARPE-19) cells was tested, which showed significant increase in caspase-14 expression compared with normal glucose (5 mM D-glucose + 25 mM L-glucose). We also evaluated the impact of modulating caspase-14 expression on RPE cells barrier function, phagocytosis, and activation of other caspases using ARPE-19 cells transfected with caspase-14 plasmid or caspase-14 siRNA. We used FITC-dextran flux assay and electric cell substrate impedance sensing (ECIS) to test the changes in RPE cell barrier function. Similar to HG, caspase-14 expression in ARPE-19 cells increased FITC-dextran leakage through the confluent monolayer and decreased the transcellular electrical resistance (TER). These effects of HG were prevented by caspase-14 knockdown. Furthermore, caspase-14 knockdown prevented the HG-induced activation of caspase-1 and caspase-9, the only activated caspases by HG. Phagocytic activity was unaffected by caspase-14 expression. Our results suggest that caspase-14 contributes to RPE cell barrier disruption under hyperglycemic conditions and thus plays a role in the development of diabetic macular edema.
Insights
High glucose increases caspase-14 in retinal cells, disrupting their barrier function. Reducing caspase-14 prevents this damage, suggesting a role in diabetic macular edema.
Area of Science:
- Ophthalmology
- Cell Biology
- Endocrinology
Background:
- Diabetic retinopathy (DR) involves vascular cell death.
- Caspase-14 was identified as a novel molecule in the retina.
- Its role in retinal pigment epithelial (RPE) cell dysfunction under hyperglycemia was unexplored.
Purpose of the Study:
- To investigate the role of caspase-14 in RPE cell dysfunction under high glucose conditions.
- To determine if caspase-14 modulates RPE barrier integrity and caspase activation.
- To assess the therapeutic potential of targeting caspase-14 in diabetic eye disease.
Main Methods:
- Human RPE (ARPE-19) cells were exposed to high glucose (HG) or normal glucose.
- Caspase-14 expression was modulated using transfection with plasmid or siRNA.
- RPE barrier function was assessed via FITC-dextran flux and electric cell substrate impedance sensing (ECIS).
- Activation of other caspases (caspase-1, caspase-9) and phagocytic activity were evaluated.
Main Results:
- High glucose significantly increased caspase-14 expression in ARPE-19 cells.
- Elevated caspase-14 mimicked HG effects, increasing RPE cell layer permeability and decreasing transcellular electrical resistance (TER).
- Caspase-14 knockdown prevented HG-induced barrier disruption and activation of caspase-1 and caspase-9.
- Phagocytic activity remained unaffected by caspase-14 modulation.
Conclusions:
- Caspase-14 contributes to retinal pigment epithelial cell barrier disruption under hyperglycemic conditions.
- Targeting caspase-14 may offer a therapeutic strategy for preventing diabetic macular edema.
- Caspase-14 is a key mediator of RPE dysfunction in diabetic eye disease.
