Induction of interleukin (IL)-1α and β gene expression in human keratinocytes exposed to repetitive strain: Their role in strain-induced keratinocyte proliferation and morphological change
✍ Scribed by Teiji Takei; Hiroyuki Kito; Wei Du; Ira Mills; Bauer E. Sumpio
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 209 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Recent studies in our laboratory have demonstrated that mechanical strain alters many facets of keratinocyte biology including proliferation, protein synthesis, and morphology. IL-1 is known to play an important role in the autocrine regulation of these basic cellular properties under basal and stimulated conditions. However, it is not known whether IL-1 plays a role in strain-induced alteration of keratinocyte biology. Thus, the objective of this study was to test the hypothesis that cyclic strain stimulates IL-1 expression and that strain-induced changes in keratinocyte function is regulated by IL-1. To test this hypothesis, we examined the effect of cyclic strain (10% average deformation) on keratinocyte IL-1 gene expression and the effect of neutralizing antibodies of IL-1␣ and IL-1 on strain-induced changes in keratinocyte proliferation, morphology, and orientation. Northern blot analyses demonstrated that steady state levels of IL-1␣ and  mRNA were elevated by 4 h, peaked at 12 h of cyclic strain (IL-1␣, 304 Ϯ 14.2%; IL-1, 212 Ϯ 5.6% increase vs. static controls) and decreased gradually by 24 h. IL-1 antibodies (IL-1␣, 0.01 µg/ml; IL-1, 0.01 µg/ml) significantly blocked strain-induced keratinocyte proliferation as well as the basal rate of proliferation. In contrast, IL-1 antibodies (IL-1␣, 0.01 µg/ml; IL-1, 0.1 µg/ml) had no effect on strain-induced morphological changes such as elongation and alignment. We conclude that mechanical strain induces IL-1 mRNA expression in keratinocytes. The role of IL-1 in mediating strain-induced changes in keratinocyte biology remains to be determined but appears to be independent of morphological changes.