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Transcriptional regulation of bone sialoprotein gene by interleukin-11

Wang, Shuang, Sasaki, Yoko, Zhou, Liming, Matsumura, Hiroyoshi, Araki, Shouta, Mezawa, Masaru, Takai, Hideki, Chen, Zhen, Ogata, Yorimasa
Gene 2011 v.476 no.1-2 pp. 46-55
antibodies, bone marrow, bone mineralization, fibroblast growth factor 2, gels, genes, immune response, interleukin-11, interleukin-6, luciferase, messenger RNA, mineralization, mutation, osteoblasts, protein binding, rats, stromal cells, transcription (genetics), transcription factors, transfection
Interleukin-11 (IL-11) is a stromal cell-derived cytokine that belongs to the interleukin-6 family of cytokines. IL-11 has many biological activities and has roles in hematopoiesis, immune responses, the nervous system and bone metabolism. Bone sialoprotein (BSP) is a mineralized tissue-specific protein expressed in differentiated osteoblasts that appears to function in the initial mineralization of bone. IL-11 (20ng/ml) increased BSP mRNA and protein levels at 12h in osteoblast-like ROS 17/2.8 cells. In a transient transfection assay, IL-11 (20ng/ml) increased luciferase activity of the construct (−116 to +60) in ROS 17/2.8 cells and rat bone marrow stromal cells. Introduction of 2bp mutations to the luciferase constructs showed that the effects of IL-11 were mediated by a cAMP response element (CRE), a fibroblast growth factor 2 response element (FRE) and a homeodomain protein-binding site (HOX). Luciferase activities induced by IL-11 were blocked by protein kinase A inhibitor, tyrosine kinase inhibitor and ERK1/2 inhibitor. Gel shift analyses showed that IL-11 (20ng/ml) increased nuclear protein binding to CRE, FRE and HOX. CREB1, phospho-CREB1, c-Fos, c-Jun, JunD and Fra2 antibodies disrupted the formation of CRE–protein complexes. Dlx5, Msx2, Runx2 and Smad1 antibodies disrupted FRE- and HOX–protein complex formations. These studies demonstrate that IL-11 stimulates BSP transcription by targeting CRE, FRE and HOX sites in the proximal promoter of the rat BSP gene. Moreover, phospho-CREB1, c-Fos, c-Jun, JunD, Fra2, Dlx5, Msx2, Runx2 and Smadl transcription factors appear to be key regulators of IL-11 effects on BSP transcription.