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In vivo cytokine expression in normal and perturbed murine skin--analysis by competitive quantitative polymerase
O Kilgus1, E Payer, S Schreiber
1Department of Dermatology I, University of Vienna Medical School, Austria.
Insights
Murine skin constitutively expresses cytokines in vivo. Tissue separation rapidly alters cytokine expression, with distinct patterns observed in the epidermis and dermis, impacting skin homeostasis and defense mechanisms.
Area of Science:
- Immunology
- Dermatology
- Molecular Biology
Background:
- In vitro studies suggest epidermal and dermal cells produce soluble mediators.
- The in vivo relevance of these in vitro findings for cytokine expression in normal skin remains unclear.
Purpose of the Study:
- To determine baseline in vivo cytokine gene expression in murine skin.
- To investigate immediate, compartment-specific alterations in cytokine expression upon perturbation.
Main Methods:
- Analysis of whole skin, epidermis, and dermis from normal adult mice.
- RNA extraction followed by conventional and competitive quantitative polymerase chain reaction (PCR).
Main Results:
- Murine skin constitutively expresses cytokine genes (e.g., interleukin-1 alpha, interleukin-6, granulocyte-macrophage colony-stimulating factor) in vivo.
- Tissue separation induced rapid upregulation of certain cytokines.
- Epidermal cells showed preferential expression of interleukin-1 alpha, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha.
- Dermal cells exhibited prominent upregulation of interleukin-6.
Conclusions:
- This study establishes baseline in vivo cytokine expression in skin.
- Perturbation, such as tissue separation, leads to immediate, compartment-specific changes in cytokine profiles.
- These findings enhance understanding of skin homeostasis and injury-induced immune responses.
Abstract:
Although cells from both epidermis and dermis have been shown to produce a variety of soluble mediators in vitro, it is not clear whether this reflects the in vivo situation. To study in vivo cytokine expression, whole skin as well as dispase-separated epidermis and dermis from normal adult mice were prepared and snap-frozen immediately. RNA was then extracted and analyzed both by conventional and by competitive quantitative polymerase chain reaction. Molecular analysis showed that murine skin in vivo constitutively expresses several cytokine genes at moderate (e.g., interleukin-1 alpha) or low (e.g., interleukin-6 and granulocyte-macrophage colony-stimulating factor) abundance. A striking, rapid upregulation was observed for some of these cytokines in the process of tissue separation. Of interest, the epidermal and dermal compartments exhibited different induction patterns: interleukin-1 alpha, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha expression were detected preferentially in the epidermis, whereas upregulation of interleukin-6 was found to be most prominent in the dermis. This pattern of cytokine expression was also reflected in supernatants generated from the respective single-cell suspensions. Thus, this study determines the baseline in vivo cytokine expression in the skin and the occurrence of immediate, compartment-specific alterations on perturbation. These data should contribute to our understanding of both skin homeostasis and the host-defense mechanisms initiated following injury to this organ.