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Abstract

Background: Macular edema, a frequently encountered complication of diabetic retinopathy (DR), results from alterations of the blood retinal barrier (BRB) and leads to modifications of the retinal pigmented epithelium (RPE) functions. Osmolar changes of the surrounding medium could be responsible for modifications of the RPE functions leading to disturbance of retinal homeostasis. The expression, activation and function of the key hyperosmolar response factor Tonicity Enhancer Binding Protein (TonEBP also called nuclear factor of activated T-cell 5 -NFTA5) was investigated in ARPE-19 cells, derived from human RPE, in response to hyperosmolar stimulation. Material and methods: ARPE-19 cells were exposed to hyperosmolar medium. TonEBP mRNA and protein levels were quantified by qRT-PCR and semi-quantitative Western blot. TonEBP nuclear translocation was investigated by immunofluorescence. TonEBP transactivation activity was measured using a reported plasmid containing TonEBP binding sites. Results: Hyperosmolar stimulation of ARPE-19 cells induced a dose-dependent increase in TonEBP mRNA and protein levels, as well as TonEBP nuclear translocation. TonEBP transactivation activity was demonstrated using a reporter plasmid containing TonEBP binding sites. A dominant negative form of TonEBP abolished NaCl-induced increase in TonEBP transactivation activity, and inhibited the increase of the target genes aldose reductase and sodium-dependent taurine transporter mRNA levels. SB203580, an inhibitor of two of p38 protein kinase inhibited the TonEBP nuclear translocation and transactivation activity in ARPE-19 cells exposed to hyperosmolar stimulation. Conclusions: Our data demonstrate the involvement of TonEBP in the mechanisms responsible for osmoadaptation to hyperosmolar stress in RPE cells. These data open new perspectives for the analysis of the mechanisms involved in the modification of functions of the RPE during macular edema. 1.02Treatment of symptomatic familial mediterranean fever (FMF). Colchicine, biologic agents and more. experience in apulia and basilicata regions, Italy † Gastrointestinal Endoscopy Unit, Ospedale della Murgia "F. Perinei", Altamura, Bari, Italy Background: FMF is rare autosomal recessive autoinflammatory disorder involving the innate immunity and affecting almost exclusively populations with Mediterranean origin. FMF cases are spread across Europe because of the historical migrations. A cluster of Italian patients was recently identified in Apulia and Basilicata (Altamura, Matera). Clinical features include recurrent episodes of fever, leukocitosis, serositis (peritonitis or pleuritis, arthritis), myalgia or erysipelas-like skin lesions, lasting 12-72 hrs. The MEFV gene mutations on chromosome 16p13.3 encodes the abnormal pyrin (marenostrin), a protein expressed in granulocytes, monocytes, serosal and synovial fibroblasts and involved in the activation of caspase-1 and the processing and release of active pro-inflammatory IL-1b. Methods: Since 1972, maintenance therapy with colchicine, a tr...