Contribution of p38 MAPK, NF-κB and glucocorticoid signaling pathways to ER stress-induced increase in retinal endothelial permeability.
Diabetic retinopathy (DR) is characterized by the development of intraretinal microvascular abnormalities. Endoplasmic reticulum (ER) stress is known to play a pathogenic role in vascular impairment in DR. The present study demonstrated that the treatment of human retinal endothelial cells with ER stress inducers such as thapsigargin (Tg) and tunicamycin (Tm) significantly increased the permeability of exogenously added FITC-dextran, accompanied by a decrease of transendothelial electrical resistance (TEER). The expression of claudin-5 among tight junction proteins was significantly decreased by the treatment with Tg or Tm. A p38 MAPK inhibitor, SB203580, and an NF-κB inhibitor, dexamethasone, significantly suppressed the Tg-induced down-regulation of claudin-5, decrease of TEER and leakage of added FITC-dextran. The translocation of NF-κB p65 subunit to the nucleus was also inhibited by the addition of SB203580 or dexamethasone. The effects of dexamethasone are thought to be due to the transrepression of the above signaling and direct regulation of claudin-5 gene.
Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, Japan. adachi@gifu-pu.ac.jp
Tetsuo
T
Adachi
Mayumi
M
Teramachi
Hiroyuki
H
Yasuda
Tetsuro
T
Kamiya
Hirokazu
H
Hara
D002199:Capillary Permeability / Q000502:physiology; D002460:Cell Line; D004721:Endoplasmic Reticulum; D042783:Endothelial Cells / Q000502:physiology*; D005938:Glucocorticoids / Q000378:metabolism*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D012160:Retina / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D005938:Glucocorticoids; D016328:NF-kappa B; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases