title: Membrane-Permeable Calpain Inhibitors Promote Rat Oral Mucosal Epithelial Cell Proliferation by Inhibiting IL-1α Signaling.
abstract: To standardise regenerative medicine using cultured cells, the use of serum-free, chemically defined media will be necessary. We have reported that IL-1α inhibits the growth of epithelial cells in culture and that recombinant IL-1 receptor antagonist (IL-1RA) significantly promotes epithelial cell growth in no feeder layer condition. In this study, we examined inhibitors of calpain, a cysteine proteinase that plays crucial roles in various cellular functions, including IL-1α maturation and secretion. The culturing of epithelial cells in serum-free media supplemented with a membrane-permeable calpain inhibitor significantly promoted growth while suppressing IL-1α maturation and secretion. By contrast, non-membrane-permeable calpain inhibitor treatment did not have these effects. Interestingly, immunoblotting analysis revealed that immature, untruncated, IL-1α expression was also downregulated by cell-permeable calpain inhibitor treatment, and the difference in IL-1α gene expression increased from day 2 to day 6. Although IL-1RA has been reported to promote epithelial cell growth, we detected no synergistic promotion of epithelial cell growth using a calpain inhibitor and IL-1RA. These findings indicate that calpain inhibitors promote epithelial cell proliferation by inhibiting IL-1α maturation at an early phase of epithelial cell culture and by suppressing the positive feedback-mediated amplification of IL-1α signalling.
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan; Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kondo
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamato
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takagi
authors.affiliation: Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Namiki
authors.affiliation: Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000818:Animals; D002154:Calpain / Q000037:antagonists & inhibitors*; D002463:Cell Membrane Permeability; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D015870:Gene Expression; D053582:Interleukin-1alpha / Q000235:genetics / Q000378:metabolism*; D009061:Mouth Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D015853:Cysteine Proteinase Inhibitors; D053582:Interleukin-1alpha; D002154:Calpain