Regulatory expression of bone morphogenetic protein 6 by 2,2′-dipyridyl

• Published in: Biochimica et biophysica acta. General subjects Vol. 1864; no. 8; p. 129610
• Main Authors: Noguchi, Taiki, Ikeda, Mayuko, Murakami, Masaru, Masuzawa, Mikio, Imamura, Toru, Hashimoto, Osamu, Matsui, Tohru, Funaba, Masayuki
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2020
• Subjects: 2,2'-Dipyridyl - pharmacology; Animals; Bmp6; Bone Morphogenetic Protein 6 - genetics; Cells, Cultured; Dose-Response Relationship, Drug; Endothelial cells; Gene Expression Profiling; Gene Expression Regulation - drug effects; Humans; Iron - pharmacology; Iron-independent manner; Mice; Transcription; Transcription; Iron-independent manner; Bmp6; Endothelial cells
• ISSN: 0304-4165; 1872-8006
• DOI: 10.1016/j.bbagen.2020.129610

Expression of hepcidin, a hormone produced by hepatocytes which negatively regulates the circulating iron levels, is known to be positively regulated by BMP6, a member of transforming growth factor (TGF)-β family. Previous studies have shown that iron status is sensed by sinusoidal endothelial cells of hepatic lamina, leading to the modulation of BMP6 expression. ISOS-1, HUVEC, F-2, and SK-HEP1 endothelial cells were treated with either iron or 2,2′-dipyridyl (2DP), a cell-permeable iron-chelator, and expression level of Bmp6 was examined. To identify factors affecting Bmp6 transcription, stimulus screening for regulator of transcription (SSRT) was developed. Treatment with iron slightly increased the expression levels of Bmp6, while 2DP unexpectedly increased Bmp6 expression in a dose-dependent manner. 2DP-induced Bmp6 expression was resistant to co-treatment with iron. 2DP-induced Bmp6 expression was also detected in HUVEC, F-2 cells, and SK-HEP1 cells. Luciferase-based reporter assays indicated that forced expression of JunB increased the transcription of Bmp6. 2DP induced phosphorylation of JunB; co-treatment with SP600125 blocked the 2DP-induced Bmp6 expression partially. JunB-induced Bmp6 transcription was not affected by mutations of putative JunB-responsive elements. Some endoplasmic reticulum stress inducers increased the expression of Bmp6. SSRT revealed pathways regulating Bmp6 transcription positively and negatively. Hepa1–6 liver cells and C2C12 myogenic cells were prone to 2DP induced Bmp6 expression. The present study reveals non‑iron-regulated Bmp6 expression in endothelial cells. Regulatory expression of Bmp6 may be important as a key step for fine tuning of BMP activity. •An iron-chelator 2,2′-dipyridyl (2DP) induces Bmp6 expression in endothelial cells.•2DP-induced Bmp6 expression is iron-independent.•2DP stimulates JunB phosphorylation, leading to Bmp6 expression.•A novel screening regulator of transcription names as SSRT is developed.•2DP-induced Bmp6 expression is also detected in non-endothelial cells.