Ahmed Mohamed N, Codipilly Champa, Hogg Neil, Auten Richard L
Division of Neonatal-Perinatal Medicine, Schneider Children's Hospital and Center for Heart and Lung Research, The Feinstein Institute for Medical Research, North Shore-Long Island Jewish Health System, Manhasset, New York, USA.
Exp Lung Res. 2011 Feb;37(1):10-7. doi: 10.3109/01902148.2010.497893. Epub 2010 Nov 15.
The objective of this study was to determine whether overexpression of human extracellular superoxide dismutase (hEC-SOD) can preserve nitric oxide (NO) bioavailability. In vitro studies examined the transient expression of hEC-SOD in mouse epithelial (C10) cells and its effect on extracellular accumulation of NO, intracellular cyclic guanosine monophosphate (cGMP), and nuclear factor kappa B (NF-κB) activation under normal and oxidative stress conditions. In vivo, newborn rabbits were treated with a plasmid containing hEC-SOD cDNA or vehicle plasmid alone, followed by exposure to hyperoxia (Fio₂ = 95% for 7 days). A third group was raised under normoxic conditions. cGMP and NF-κB activation were studied. There was significantly higher NO accumulation in cells expressing hEC-SOD exposed to oxidative stress compared with nontransfected cells. Accumulation of cGMP was significantly higher in cells expressing hEC-SOD. Oxidative stress induced NF-κB activation, which was abrogated by hEC-SOD expression. In vivo, there was significantly higher cGMP accumulation in transfected neonatal rabbit lung tissue at 3 and 7 days of hyperoxic exposure. Immunostaining for NF-κB, showed a marked increase in NF-κB concentration in nontreated neonatal rabbit lung tissue compared to transfected neonatal lung with hEC-SOD and the control air group. These results show that transient EC-SOD overexpression maintains NO bioavailability, which directly leads to maintenance of cGMP activity and reduction of NF-κB activation under oxidative stress.
本研究的目的是确定人细胞外超氧化物歧化酶（hEC-SOD）的过表达是否能维持一氧化氮（NO）的生物利用度。体外研究检测了hEC-SOD在小鼠上皮（C10）细胞中的瞬时表达及其在正常和氧化应激条件下对细胞外NO积累、细胞内环磷酸鸟苷（cGMP）和核因子κB（NF-κB）激活的影响。在体内，新生兔分别用含hEC-SOD cDNA的质粒或单独的载体质粒处理，然后暴露于高氧环境（Fio₂ = 95%，持续7天）。第三组在常氧条件下饲养。研究了cGMP和NF-κB的激活情况。与未转染的细胞相比，暴露于氧化应激的hEC-SOD表达细胞中NO积累显著更高。hEC-SOD表达细胞中cGMP的积累显著更高。氧化应激诱导NF-κB激活，而hEC-SOD的表达可消除这种激活。在体内，高氧暴露3天和7天时，转染的新生兔肺组织中cGMP积累显著更高。对NF-κB进行免疫染色显示，与用hEC-SOD转染的新生兔肺组织和对照空气组相比，未处理的新生兔肺组织中NF-κB浓度显著增加。这些结果表明，瞬时EC-SOD过表达可维持NO的生物利用度，这直接导致在氧化应激下cGMP活性的维持和NF-κB激活的减少。
