Hyperpermeability of intestinal epithelial monolayers is induced by NO: effect of low extracellular pH.
Hyperpermeability of intestinal epithelial monolayers is induced by NO: effect of low extracellular pH.
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肠上皮单层的通透性过高是由 NO 引起的：低细胞外 pH 值的影响。
DOI：
10.1152/ajpgi.1997.272.5.g923
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Fink,MP
中科院分区：
文献类型：
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作者：
Unno,N;Menconi,MJ;Smith,M;Aguirre,DE;Fink,MP
一氧化氮(NO.)增加Caco-2Be肠细胞单层的通透性。NO的许多毒性作用。被认为是由过氧亚硝酸根阴离子(ONOO-)介导的，在中等酸性条件下，过氧亚硝酸根阴离子可以重排产生一种具有类似有毒OH反应活性的中间体。因此，我们评估了生长在可渗透载体上的Caco-2BBe细胞在滴定到正常或酸性细胞外pH(Pho)的条件下，在有或没有NO的情况下24小时的渗透性。供体3-吗啉-吡喃亚胺(SIN-1)或硝普钠(SNP)。在pho 6.8时与2 mM SIN-1孵育，或在pho 6.5时与0.6 mM SNP孵育可增加通透性(荧光素磺酸从根尖到基底的侧向通量)，而在pho 7.4时，通透性不受这些浓度的NO影响。捐赠者。培养基中亚硝酸盐/硝酸根的积累(NO。在中等酸性条件下与SIN-1或SNP孵育细胞，不会增加释放)。在酸性条件下，但不是控制条件，与SIN-1孵育引起周围肌动蛋白细丝的破坏，通过荧光显微镜进行评估。在pho 6.8和6.5(但不是7.4)时，SIN-1显著降低细胞内ATP和谷胱甘肽的水平。与5 mM去铁胺或500微米抗坏血酸(ONOO清除剂)孵育可消除SIN-1诱导的高通透性。我们的结论是，轻度酸中毒增加了NO诱导的肠上皮通透性，可能是通过促进氧化剂介导的细胞骨架损伤和/或ATP耗竭。
Nitric oxide (NO.) increases the permeability of Caco-2BBe enterocytic monolayers. Many of the toxic effects of NO. are thought to be mediated by the peroxynitrite anion (ONOO-), which, under mildly acidic conditions, can rearrange to yield an intermediate with reactivity similar to toxic OH.. Accordingly, we assessed the permeability of Caco-2BBe cells grown on permeable supports for 24 h in media titrated to normal or acidic extracellular pH (pHo) with or without the NO. donors 3-morpholinosydnonimine (SIN-1) or sodium nitroprusside (SNP). Incubation with 2 mM SIN-1 at pHo 6.8 or 0.6 mM SNP at pHo 6.5 increased permeability (apical-to-basolateral flux of fluorescein sulfonic acid), whereas at pHo 7.4 permeability was unaffected by these concentrations of NO. donors. Accumulation of NO2/NO3 in medium (index of NO. release) was not increased by incubation of cells with SIN-1 or SNP under mildly acidic conditions. Under acidic but not control conditions, incubation with SIN-1 caused disruption of perijunctional actin filaments as assessed by fluorescence microscopy. At pHo 6.8 and 6.5 (but not 7.4), SIN-1 significantly decreased intracellular levels of both ATP and glutathione. Incubation with 5 mM deferoxamine or 500 uM ascorbic acid (ONOO- scavengers) abrogated SIN-1-induced hyperpermeability. We conclude that mild acidosis augments NO.-induced intestinal epithelial permeability, possibly by promoting oxidant-mediated cytoskeletal damage and/or ATP depletion.