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ICAM-1 expression in a spontaneously transformed human keratinocyte cell line: characterization by a simple
1Department of Dermatology, Sandoz Research Institute, Vienna, Austria.
Insights
Interferon gamma (IFN-gamma) upregulates intercellular adhesion molecule-1 (ICAM-1) on keratinocytes. This study shows HaCaT cells are a reliable model for investigating ICAM-1 induction and potential drug therapies.
Area of Science:
- Immunology
- Dermatology
- Cell Biology
Background:
- Interferon gamma (IFN-gamma) is known to induce ICAM-1 on keratinocytes (KC).
- The mechanisms of cytokine-mediated ICAM-1 expression in KC remain largely unknown.
- ICAM-1 expression in vivo correlates with T-cell infiltration in skin diseases.
Purpose of the Study:
- To investigate the mechanisms of IFN-gamma-induced ICAM-1 expression in HaCaT cells.
- To establish HaCaT cells as a reliable model for studying ICAM-1 modulation on KC.
- To explore the synergistic effects of TNF-alpha and IFN-gamma on ICAM-1 expression.
Main Methods:
- Utilized HaCaT cells, a human keratinocyte cell line.
- Employed immunoperoxidase-ELISA with monoclonal antibody R6.5 to quantify ICAM-1.
- Assessed ICAM-1 mRNA levels via Northern blotting and cell adhesion using an in vitro adhesion assay.
Main Results:
- IFN-gamma significantly upregulated constitutive ICAM-1 expression in HaCaT cells in a time- and dose-dependent manner.
- TNF-alpha alone and in synergy with IFN-gamma also increased HaCaT ICAM-1 expression.
- IFN-gamma treatment enhanced T-lymphoblast adherence to HaCaT cells, indicating increased functional ICAM-1.
Conclusions:
- HaCaT cells provide a reproducible system for studying IFN-gamma-mediated ICAM-1 induction.
- This model can be used to investigate the pharmacologic modulation of ICAM-1 on keratinocytes.
- Findings contribute to understanding immune cell interactions in dermatological conditions.
Abstract:
Interferon gamma (IFN-gamma) is known to induce ICAM-1 on keratinocytes (KC) in vitro, and its expression in vivo is correlated with epidermal T-cell infiltration in various dermatoses. However, the mechanisms for this cytokine-mediated ICAM-1 expression are essentially unknown. We investigated the induction of ICAM-1 by IFN-gamma in HaCaT cells, a spontaneously transformed human KC cell line, using an immunoperoxidase-ELISA with the monoclonal antibody (MoAb) R6.5. HaCaT cells constitutively expressed low levels of ICAM-1, which were upregulated by IFN-gamma. The kinetics and dose response were similar to those published for primary KC, regardless of whether the HaCaT cells were cultured in low- or high-calcium medium. ICAM-1 expression was increased significantly at 4 h with 500 U/ml IFN-gamma, and reached a plateau (approximately 5 x greater than constitutive) by 24 h. At concentrations greater than 10 U/ml for 24 h, IFN-gamma induced ICAM-1 expression in a dose-dependent fashion (half maximal at 100 U/ml). TNF-alpha alone, and in synergistic combination with IFN-gamma, also upregulated the expression of HaCaT ICAM-1. IFN-gamma treatment of HaCaT cells increased the level of ICAM-1 mRNA and enhanced (approximately 3x) the adherence of fluorescently labeled (calcein) human T lymphoblasts, as determined by Northern blotting and an in vitro adhesion assay, respectively. Our findings suggest that HaCaT cells, in conjunction with a simple immunoperoxidase cell-ELISA, provide a reliable system for studying pharmacologic modulation of ICAM-1 on KC.