期刊
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY
卷 287, 期 4, 页码 C1139-C1151出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpcell.00146.2004
关键词
tubulin cytoskeleton; microtubules; oxidation/nitration; inducible nitric oxide synthase/peroxynitrite; inflammatory bowel disease; Caco-2 cells; gut barrier; nuclear factor-kappa B/I kappa B alpha
资金
- NIAAA NIH HHS [AA-13745] Funding Source: Medline
- NIDDK NIH HHS [R01 DK-60511] Funding Source: Medline
Using monolayers of intestinal cells, we reported that upregulation of inducible nitric oxide synthase ( iNOS) is required for oxidative injury and that activation of NF-kappaB is key to cytoskeletal instability. In the present study, we hypothesized that NF-kappaB activation is crucial to oxidant-induced iNOS upregulation and its injurious consequences: cytoskeletal oxidation and nitration and monolayer dysfunction. Wild-type (WT) cells were pretreated with inhibitors of NF-kappaB, with or without exposure to oxidant (H2O2). Other cells were transfected with an IkappaBalpha mutant ( an inhibitor of NF-kappaB). Relative to WT cells exposed to vehicle, oxidant exposure caused increases in IkappaBalpha instability, NF-kappaB subunit activation, iNOS-related activity ( NO, oxidative stress, tubulin nitration), microtubule disassembly and instability ( increased monomeric and decreased polymeric tubulin), and monolayer disruption. Monolayers pretreated with NF-kappaB inhibitors (MG-132, lactacystin) were protected against oxidation, showing decreases in all measures of the NF-kappaB --> iNOS --> NO pathway. Dominant mutant stabilization of IkappaBalpha to inactivate NF-kappaB suppressed all measures of the iNOS/NO upregulation while protecting monolayers against oxidant insult. In these mutants, we found prevention of tubulin nitration and oxidation and enhancement of cytoskeletal and monolayer stability. We concluded that 1) NF-kappaB is required for oxidant-induced iNOS upregulation and for the consequent nitration and oxidation of cytoskeleton; 2) NF-kappaB activation causes cytoskeletal injury following upregulation of NO-driven processes; and 3) the molecular event underlying the destabilizing effects of NF-kappaB appears to be increases in carbonylation and nitrotyrosination of the subunit components of cytoskeleton. The ability to promote NO overproduction and cytoskeletal nitration/oxidation is a novel mechanism not previously attributed to NF-kappaB in cells.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据