THE PHOSPHOLIPASE D PATHWAY MEDIATES THE EXPRESSION OF PRO-INFLAMMATORY CYTOKINES AND CYCLOOXYGENASE-2 IN RETINAL PIGMENT EPITHELIUM CELLS EXPOSEDTO HIGH GLUCOSE CONCENTRATIONS

TENCONI, PAULA ESTEFANÍA; BERMÚDEZ, VICENTE; ORESTI, GERARDO MARTÍN; GIUSTO, NORMA MARÍA; SALVADOR, GABRIELA ALEJANDRA; MATEOS, MELINA VALERIA

Buenos Aires

Simposio; Frontiers in Bioscience 3; 2018

Investigación en Biomedicina de Buenos Aires ? CONICET ? Instituto Partner de la Sociedad Max Planck (IBioBA-CONICET-MPSP)

Diabetic retinopathy (DR) is the leading cause of vision loss in the working age population in which oxidative stress, chronic hyperglycemia and inflammation are key players in its pathogenesis.The aim of the present work is to study the role of classical phospholipases D (PLD1 and PLD2) in retinal pigment epithelium (RPE) cells exposed to high glucose (HG) concentrations.Human RPE cell lines ARPE-19 and D407 were exposed to normal glucose concentration (NG, 5.5 mM) or to HG concentrations (16.5 or 33 mM) for 4, 24 or 72 h.To study the role of classical PLDs and the ERK1/2 pathway cells were pre-incubated for 1 h with EVJ (VU0359595, 0.15 μM) to inhibit PLD1 activity, with APV (VU0285655-1, 0.5 μM) to inhibit PLD2 or with U0126 (10 µM) to inhibit the MEK/ERK1/2 pathway, prior to cell exposure to HG. Our results demonstrate that exposure to HG increases reactive oxygen species levels and caspase-3 cleavage and reduces cell viability. In addition, HG exposure for 4 h induces early and concatenated events, as PLD, ERK and nuclear factor kappa B (NFκB) activation. NFκB activation induced by HG correlates with the increment in pro-inflammatory interleukins (IL-6 and IL-8) and cyclooxygenase-2 (COX-2) mRNA levels. The effect of selective pharmacological PLD1 and PLD2 inhibitors demonstrates that ERK1/2 and NFκB activation depends on both PLD isoforms. Besides, the increment in IL-6 and COX-2 mRNA levels induced by HG is inhibited to control levels in cells pre-incubated with both PLD inhibitors and the inhibition of classical PLDs and the MEK/ERK1/2 pathway prevents the loss of cell viability and caspase-3 activation induced by HG.In conclusion, our findings constitute the first evidence that PLD1 and PLD2 participate in the inflammatory response of RPE cells exposed to HG, pointing to the use of these signaling enzymes as potential therapeutic targets for DR treatment.