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NITROTYROSINATION OF A TUBULIN INDUCES EPITHELIAL BARRIER DYSFUNCTION
Citation:
Huang, YuhChin T, L. A. Dailey, C. Zhang WenLi, AND I. Jasper. NITROTYROSINATION OF A TUBULIN INDUCES EPITHELIAL BARRIER DYSFUNCTION. Presented at Oxygen Society Meeting, RTP, NC, November 11-15, 2001.
Description:
Nitrotyrosination of a-Tubulin Induces Epithelial Transport Dysfunction. Yuh-Chin Huang, Lisa Dailey, Wen-Li Zhang and Ilona Jaspers. ORD, Environmental Protection Agency and CEMLB, University of North Carolina
a-Tubulin undergoes a cyclic removal and readdition of tyrosine at the C-terminus during the generation of microtubule populations. Tyrosination of a-tubulin is catalyzed by tubulin tyrosine ligase, which can also use 3-nitrotyrosine as a substrate. Nitrotyrosination of a-tubulin alters cell morphology and microtubule functions in a tumor cell line, but the effect on lung epithelium in which the integrity of microtubules is essential for transcellular transport functions is unknown. Human bronchial epithelial cells obtained by bronchoscopic brushings were cultured in air-liquid interface supplemented with 0-250 mM of 3-nitrotyrosine for 7 days. Epithelial barrier function was assessed by the apical-basal permeation of a hydrophobic solute, rhodamine B (RhB), and a hydrophilic solute, FITC-dextran 4000 (FD4). Permeation of RhB and FD-4 was attenuated when nitrotyrosine concentration exceeded 25 mM. Western blotting with a nitrotyrosine antibody showed significant nitrotyrosination of a-tubulin. Permeation of RhB and FD4 was not affected in cells incubated with a peroxynitrite donor, SIN-1 or NO donors, PAPANONOate and GSNO. Epithelial permeation of RhB and FD4 was also inhibited in isolated lungs perfused with physiological buffer containing 1 mM of 3-nitrotyrosine. These results indicate that increased extracellular free nitrotyrosine, which occurs during oxidative and nitrosative stress, may alter the transcellular and paracellular transport function of lung epithelium via nitrotyrosination of a-tubulin. (This abstract does not reflect EPA policy).