Mathew Biji, Park Gye Young, Cao Hongmei, Azim Anser C, Wang Xuerong, Van Breemen Richard B, Sadikot Ruxana T, Christman John W
Section of Pulmoary, Critical Care and Sleep Medicine, Department of Medicine, University of Illinois, and Jesse Brown Veterans Affairs Medical Center, Chicago, IL 60612, USA.
Am J Respir Cell Mol Biol. 2007 May;36(5):562-72. doi: 10.1165/rcmb.2006-0245OC. Epub 2007 Jan 4.
It has not been resolved whether macrophages or airway epithelial cells primarily respond to infectious and inflammatory stimuli and initiate a cell-to-cell inflammatory interaction within the airways. We hypothesized that the airway epithelial cells are primary responders that activate macrophages in response to environmental stimuli. To investigate the unilateral contribution of airway epithelial cells in the activation of macrophages, we developed an in vitro system in which the primary mouse tracheal epithelial cells (MTEC) and primary bone marrow-derived macrophages (BMDM) were incubated together for a brief period of time in a Transwell culture plate. MTEC were transfected with adenoviral vectors that express a constitutively active form of IKK2 (Ad-cIKK2), Ad-beta-Gal, or PBS for 48 h before incubating with the macrophages. Macrophage activation was determined by measuring surface expression of CD11b, activation of NF-kappaB, phagocytic activity and production of reactive oxygen species, and cyclooxygenase (COX)-2 gene expression and production of prostaglandins. Macrophage adherence to epithelial layer was confirmed by CD68 immunostaining and scanning electron microscopy. MTEC cells transfected with Ad-cIKK2 produced increased amounts of IL-6, mouse GRO-alpha, TNF-alpha, and prostaglandin (PG)E2. Exposure of BMDM to MTEC, transfected with Ad-cIKK2, led to an increase in the CD11b expression and increased adherence of macrophages to the epithelial cell layer. NF-kappaB activation, COX-2 gene expression, and PGD2 synthesis were also increased in BMDM that were incubated with MTEC transfected with Ad-cIKK2. These data suggest that airway epithelial cells potentially play a primary role in generating inflammatory signals that result in activation of macrophages.
巨噬细胞或气道上皮细胞是否主要对感染性和炎性刺激作出反应并在气道内启动细胞间炎性相互作用，这一问题尚未得到解决。我们推测气道上皮细胞是主要的反应细胞，可响应环境刺激而激活巨噬细胞。为了研究气道上皮细胞在巨噬细胞激活中的单方面作用，我们开发了一种体外系统，将原代小鼠气管上皮细胞（MTEC）和原代骨髓来源的巨噬细胞（BMDM）在Transwell培养板中共同孵育短时间。在与巨噬细胞孵育前48小时，用表达组成型活性形式IKK2的腺病毒载体（Ad-cIKK2）、Ad-β-Gal或PBS转染MTEC。通过测量CD11b的表面表达、NF-κB的激活、吞噬活性和活性氧的产生，以及环氧合酶（COX）-2基因表达和前列腺素的产生来确定巨噬细胞的激活。通过CD68免疫染色和扫描电子显微镜确认巨噬细胞对上皮层的粘附。用Ad-cIKK2转染的MTEC细胞产生的IL-6、小鼠GRO-α、TNF-α和前列腺素（PG）E2量增加。将BMDM暴露于用Ad-cIKK2转染的MTEC，导致CD11b表达增加以及巨噬细胞对上皮细胞层的粘附增加。在用Ad-cIKK2转染的MTEC孵育的BMDM中，NF-κB激活、COX-2基因表达和PGD2合成也增加。这些数据表明气道上皮细胞可能在产生导致巨噬细胞激活的炎性信号中起主要作用。
