Role of H1-Calponin in Pancreatic AR42J Cell Differentiation Into Insulin-Producing Cells
- Tomoaki Morioka1,
- Hidenori Koyama1,
- Hisako Yamamura2,
- Shinji Tanaka1,
- Shinya Fukumoto1,
- Masanori Emoto1,
- Hiroyuki Mizuguchi3,
- Takao Hayakawa3,
- Itaru Kojima4,
- Katsuhito Takahashi2 and
- Yoshiki Nishizawa1
- 1Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
- 2Department of Molecular Medicine and Pathophysiology, Osaka Medical Center for Cancer and Cardiovascular Diseases, the Graduate School of Pharmaceutical Science, Osaka University, SORST, JST, Osaka, Japan
- 3Division of Biological Chemistry and Biologicals, National Institute of Health Sciences, Tokyo, Japan
- 4Department of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
Abstract
Basic or h1-calponin is a smooth muscle–specific, actin-binding protein that is involved in the regulation of smooth muscle contractile activity. We found in this study the expression of mRNA and protein for h1-calponin in AR42J-B13 cells, which is a useful model for investigating islet β-cell differentiation from pancreatic common precursor cells. Following treatment of AR42J cells with activin A and hepatocyte growth factor, the protein levels of h1-calponin decreased in a time-dependent manner during the course of the cell differentiation. When h1-calponin was continuously overexpressed by utilizing recombinant adenovirus-mediated gene transfer, the percentage of cell differentiation in h1-calponin overexpressing cells was markedly suppressed as compared with that in the cells without overexpression (6.7 ± 2.5 vs. 28.6 ± 3.2%, P < 0.001, Student’s t test). Finally, overexpression of h1-calponin (65.6 ± 3.4), or that lacking actin-binding domain (55.9 ± 3.4%), significantly (P < 0.001) suppressed the activin A–stimulated transcriptional activity of activin responsive element (ARE), whereas calponin homology-domain disruption mutant did not (100.6 ± 1.9%). These results suggest that regulation of h1-calponin is involved in the regulation of differentiation of AR42J cells into insulin-producing cells at least partly through modulating ARE transcriptional activity.
Footnotes
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Address correspondence and reprint requests to Hidenori Koyama, MD, PhD, Department of Metabolism, Endocrinology and Molecular Medicine, (Second Department of Internal Medicine), Osaka City University Graduate School of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545-8585, Japan. E-mail: hidekoyama{at}med.osaka-cu.ac.jp.
Received for publication 29 May 2002 and accepted in revised form 9 December 2002.
ABD, actin-binding domain; ARE, activin responsive element; β-gal, β-galactosidase; CHD mt, calponin homology-domain disruption mutant; ERK, extracellular regulated kinase; FITC, fluorescein isothiocyanate; FSH, follicle-stimulating hormone; GABA, γ-aminobutyric acid; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; HEK, human embryonic kidney; HGF, hepatocyte growth factor; MOI, multiplicity of infection; pGL2-ARE, pGL2-basic containing activin responsive element; SMC, smooth muscle cell; UTR, untranslated region.
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