title: Cathepsin D: an Mϕ-derived factor mediating increased endothelial cell permeability with implications for alteration of the blood-retinal barrier in diabetic retinopathy.
abstract: Inflammation plays an important role in the pathogenesis of diabetic retinopathy (DR). We have previously reported increased monocyte (Mono) trafficking into the retinas of diabetic animals. In this study, we have examined the effect of activated Monos on retinal endothelial cells (ECs). The U937 Mϕ-conditioned medium (CM) significantly decreased the transendothelial resistance of EC monolayers as measured by electric cell-substrate impedance sensing (P= 0.007). The CM was fractioned, and the effective fraction (30-100 kDa) was analyzed by liquid chromatography-mass spectrometry, and cathepsin D (CD) was identified as a major secreted product. Immunoprecipitated CD resulted in decreased resistance in ECs (P= 0.006). The specificity of CD in mediating alterations of the EC barrier was confirmed using small interfering RNA. The decreased resistance correlated with a significantly increased gap between ECs. CD altered the Ras homolog gene family, member A/Rho-associated kinase pathway with increased stress actin filament formation in the EC layer. Increased CD levels were found in the retinas of diabetic mice (3-fold) and serum samples of patients with diabetic macular edema (1.6-fold) measured by Western blot and ELISA. These findings suggest an important role for Mϕ-derived CD in altering the blood-retinal barrier and reveal a potential therapeutic target in the treatment of DR.-Monickaraj, F., McGuire, P. G., Nitta, C. F., Ghosh, K., Das, A. Cathepsin D: an Mϕ-derived factor mediating increased endothelial cell permeability with implications for alteration of the blood-retinal barrier in diabetic retinopathy.
authors.affiliation: *Department of Surgery and Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA; New Mexico Veterans Affairs Health Care System, Albuquerque, New Mexico, USA; and Department of Bioengineering, University of California, Riverside, Riverside, California, USA.
authors.forename: Finny
authors.initials: F
authors.lastname: Monickaraj
authors.affiliation: *Department of Surgery and Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA; New Mexico Veterans Affairs Health Care System, Albuquerque, New Mexico, USA; and Department of Bioengineering, University of California, Riverside, Riverside, California, USA.
authors.forename: Paul G
authors.initials: PG
authors.lastname: McGuire
authors.affiliation: *Department of Surgery and Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA; New Mexico Veterans Affairs Health Care System, Albuquerque, New Mexico, USA; and Department of Bioengineering, University of California, Riverside, Riverside, California, USA.
authors.forename: Carolina Franco
authors.initials: CF
authors.lastname: Nitta
authors.affiliation: *Department of Surgery and Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA; New Mexico Veterans Affairs Health Care System, Albuquerque, New Mexico, USA; and Department of Bioengineering, University of California, Riverside, Riverside, California, USA.
authors.forename: Kaustabh
authors.initials: K
authors.lastname: Ghosh
authors.affiliation: *Department of Surgery and Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA; New Mexico Veterans Affairs Health Care System, Albuquerque, New Mexico, USA; and Department of Bioengineering, University of California, Riverside, Riverside, California, USA adas@unm.edu.
authors.forename: Arup
authors.initials: A
authors.lastname: Das
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001813:Blood-Retinal Barrier / Q000378:metabolism*; D015153:Blotting, Western; D002199:Capillary Permeability; D002402:Cathepsin D / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000097:blood / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008264:Macrophages / Q000201:enzymology; D008269:Macular Edema / Q000097:blood / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008875:Middle Aged; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020298:U937 Cells; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D054460:rho-Associated Kinases; D002402:Cathepsin D
keywords: DME; Rho/ROCK pathway; inflammation