Sappington Penny L, Yang Runkuan, Yang Huan, Tracey Kevin J, Delude Russell L, Fink Mitchell P
Department of Critical Care Medicine, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261, USA.
Gastroenterology. 2002 Sep;123(3):790-802. doi: 10.1053/gast.2002.35391.
BACKGROUND & AIMS: High mobility group (HMG) B1 is a nonhistone nuclear protein that was recently identified as a late-acting mediator of lipopolysaccharide-induced lethality in mice. The proinflammatory actions of HMGB1 have been localized to a region of the molecule called the B box.
To determine whether HMGB1 or B box are capable of causing derangements in intestinal barrier function, we incubated cultured Caco-2 human enterocytic monolayers with recombinant human HMGB1 or a 74-residue truncated form of the protein consisting of the B box domain.
Both HMGB1 and B box increased the permeability of Caco-2 monolayers to fluorescein isothiocyanate-labeled dextran (FD4) in a time- and dose-dependent fashion. The increase in permeability was reversible following removal of the recombinant protein. Exposure of Caco-2 cells to B box resulted in increased expression of inducible nitric oxide synthase messenger RNA and increased production of NO. When we used various pharmacologic strategies to inhibit NO production or scavenge NO or peroxynitrite (ONOO(-)), we abrogated B box-induced hyperpermeability. Administration of B box to wild-type mice increased both ileal mucosal permeability to FD4 and bacterial translocation to mesenteric lymph nodes. These effects were not observed in inducible nitric oxide synthase knockout mice.
These data support the view that HMGB1 and B box are capable of causing alterations in gut barrier function via a mechanism that depends on the formation of NO and ONOO(-).
高迁移率族（HMG）B1是一种非组蛋白核蛋白，最近被确定为脂多糖诱导小鼠致死的晚期作用介质。HMGB1的促炎作用定位于该分子的一个称为B盒的区域。
为了确定HMGB1或B盒是否能够导致肠道屏障功能紊乱，我们将培养的Caco-2人肠上皮细胞单层与重组人HMGB1或由B盒结构域组成的74个残基的截短形式的蛋白质一起孵育。
HMGB1和B盒均以时间和剂量依赖性方式增加Caco-2单层对异硫氰酸荧光素标记的葡聚糖（FD4）的通透性。去除重组蛋白后，通透性增加是可逆的。将Caco-2细胞暴露于B盒导致诱导型一氧化氮合酶信使核糖核酸表达增加和NO产生增加。当我们使用各种药理学策略抑制NO产生或清除NO或过氧亚硝酸盐（ONOO(-)）时，我们消除了B盒诱导的高通透性。给野生型小鼠施用B盒增加了回肠粘膜对FD4的通透性以及细菌向肠系膜淋巴结的移位。在诱导型一氧化氮合酶基因敲除小鼠中未观察到这些效应。
这些数据支持以下观点，即HMGB1和B盒能够通过一种依赖于NO和ONOO(-)形成的机制导致肠道屏障功能改变。
