Ritzenthaler J D, Roman J
Pulmonary & Critical Care Division, Department of Medicine, Atlanta Veterans Affairs Medical Center and Emory University School of Medicine, Atlanta, GA 30033, USA.
J Interferon Cytokine Res. 2001 Feb;21(2):105-16. doi: 10.1089/107999001750069971.
Type I collagen (Col), an extracellular matrix molecule highly expressed in injured tissues, stimulates interleukin-1beta (IL-1beta) expression in monocytic cells. Using U937 cells transfected with the human IL-1beta gene promoter connected to a reporter gene, we examined how the organizational state of the cytoskeleton modulates the expression of IL-1beta after Col stimulation. We found the same degree of stimulation of IL-1beta gene transcription in cells exposed to Col presented in different fashions (i.e., soluble Col, Col-coated plate, three-dimensional Col lattice), suggesting that stimulation of IL-1beta is independent of the mode of presentation of Col. The Col-stimulated response was associated with induction of the transcription factor activator protein-1 (AP-1) and was abolished by a protein kinase C (PKC) inhibitor, by a mitogen-activated protein kinase (MAPK) inhibitor, and by cotransfection of cells with a competing AP-1 oligo. Disruption of cytoskeletal organization with colchicine or cytochalasin B stimulated IL-1beta gene transcription and enhanced the cells' response to Col. The effects of cytochalasin and colchicine were inhibited by the PKC inhibitor but were not affected by the MAPK inhibitor or the AP-1 oligo. These findings suggest that the cytoskeletal integrity modulates the constitutive and Col-stimulated transcription of the IL-1beta gene via distinct signaling mechanisms.
I型胶原蛋白（Col）是一种在受损组织中高表达的细胞外基质分子，可刺激单核细胞中白细胞介素-1β（IL-1β）的表达。我们使用转染了与报告基因相连的人IL-1β基因启动子的U937细胞，研究了细胞骨架的组织状态如何在Col刺激后调节IL-1β的表达。我们发现，暴露于不同形式（即可溶性Col、Col包被板、三维Col晶格）的Col的细胞中，IL-1β基因转录的刺激程度相同，这表明IL-1β的刺激与Col的呈现方式无关。Col刺激的反应与转录因子激活蛋白-1（AP-1）的诱导有关，并被蛋白激酶C（PKC）抑制剂、丝裂原活化蛋白激酶（MAPK）抑制剂以及用竞争性AP-1寡核苷酸共转染细胞所消除。用秋水仙碱或细胞松弛素B破坏细胞骨架组织可刺激IL-1β基因转录，并增强细胞对Col的反应。细胞松弛素和秋水仙碱的作用被PKC抑制剂抑制，但不受MAPK抑制剂或AP-1寡核苷酸的影响。这些发现表明，细胞骨架的完整性通过不同的信号机制调节IL-1β基因的组成型和Col刺激的转录。
