title: Caspase-14 expression impairs retinal pigment epithelium barrier function: potential role in diabetic macular edema.
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.
authors.affiliation: Cellular 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.
authors.forename: Selina
authors.identifier: 0000-0001-6728-6400
authors.initials: S
authors.lastname: Beasley
authors.affiliation: 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 ; Department of Anatomy, Mansoura Faculty of Medicine, Mansoura University, Mansoura, Egypt.
authors.forename: Mohamed
authors.identifier: 0000-0002-2689-1409
authors.initials: M
authors.lastname: El-Sherbiny
authors.affiliation: 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.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Megyerdi
authors.affiliation: Oral Biology/Anatomy, College of Dental Medicine, GRU, Augusta, GA 30912, USA.
authors.forename: Sally
authors.initials: S
authors.lastname: El-Shafey
authors.affiliation: Oral Biology/Anatomy, College of Dental Medicine, GRU, Augusta, GA 30912, USA.
authors.forename: Karishma
authors.initials: K
authors.lastname: Choksi
authors.affiliation: Department of Physiology, Medical College of Georgia, GRU and Charlie Norwood VA Medical Center, Augusta, GA 30912, USA.
authors.forename: Ismail
authors.initials: I
authors.lastname: Kaddour-Djebbar
authors.affiliation: Departments of Ophthalmology and Visual Sciences and Biomedical Engineering, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA.
authors.forename: Nader
authors.initials: N
authors.lastname: Sheibani
authors.affiliation: Oral Biology/Anatomy, College of Dental Medicine, GRU, Augusta, GA 30912, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Hsu
authors.affiliation: Cellular 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 ; Department of Anatomy, Mansoura Faculty of Medicine, Mansoura University, Mansoura, Egypt.
authors.forename: Mohamed
authors.identifier: 0000-0001-5362-7972
authors.initials: M
authors.lastname: Al-Shabrawey
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D053456:Caspase 14 / Q000378:metabolism*; D002460:Cell Line; D003911:Dextrans / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000201:enzymology* / Q000473:pathology; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D055785:Gene Knockdown Techniques; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D008269:Macular Edema / Q000201:enzymology* / Q000473:pathology; D008954:Models, Biological; D010539:Permeability / Q000187:drug effects; D010587:Phagocytosis / Q000187:drug effects; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology*
chemical_list: D003911:Dextrans; C015219:fluorescein isothiocyanate dextran; D053456:Caspase 14; D016650:Fluorescein-5-isothiocyanate; D005947:Glucose