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.
Highlights
Following the establishment of the human epidermal keratinocyte culture method using foetal bovine serum (FBS) and a 3T3 feeder layer [1, 2], fabricated epidermal cell sheets have been used as epidermal grafts to treat skin defects, such as severe burns [3], ulcers [4] and giant congenital nevi [5]
Based on screens for cytokines with epithelial cell proliferation activity, we reported that IL-1α inhibits the growth of epithelial cells, whereas IL-1 receptor antagonist (IL-1RA) promotes growth [14]
Rat oral mucosal epithelial cells were seeded at a density of 4.0 × 104 cells/cm2 and were cultured for 2, 4, 6, 8, or 10 days
Summary
Following the establishment of the human epidermal keratinocyte culture method using foetal bovine serum (FBS) and a 3T3 feeder layer [1, 2], fabricated epidermal cell sheets have been used as epidermal grafts to treat skin defects, such as severe burns [3], ulcers [4] and giant congenital nevi [5]. This culture method has been applied to oral mucosal epithelial cells [6] and used clinically to treat skin [7, 8] and oral defects [7, 9, 10]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.