S179D prolactin diminishes the effects of UV light on epidermal gamma delta T cells (original) (raw)
2008, Molecular and Cellular Endocrinology
Langerhans cells (LC) are immune cells altered by exposure to ultraviolet radiation (UVB), a powerful stressor resulting in immune suppression. Prolactin (PRL) has been characterized as an immunomodulator, particularly during stress. In this study, we have asked whether separate administration of the two major forms of prolactin, unmodified and phosphorylated, to groups of 15 mice (3 experiments, each with 5 mice per treatment group) affected the number and morphology of these epidermal immune cells under control conditions, and following UV irradiation. Under control conditions, both PRLs reduced the number of γδ T, but a molecular mimic of phosphorylated PRL (S179D PRL) was more effective, resulting in a 30% reduction. In the irradiated group, however, S179D PRL was protective against a UV-induced reduction in γδ T number and change in morphology (halved the reduction and normalized the morphology). In addition, S179D PRL, but not unmodified (U-PRL), maintained a normal LC: γδ T ratio and sustained the dendritic morphology of LC after UV exposure. These findings suggest that S179D PRL may have an overall protective effect, countering UV-induced cellular alterations in the epidermis.
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Ultraviolet radiation and the skin immune response
ACTA CLINICA …, 2003
At present, ultraviolet radiation (UVR) represents one of the most important environmental factors affecting mankind. Besides the beneficial effects of UVR such as vitamin D production, it is known that UVR can lead to adverse effects on human health. The best known harmful effects are sunburns, tumors of the skin and ocular damage. It is noteworthy that UVR effects are not restricted to skin-associated infections, as there is strong evidence for their association with systemic (non-skin-associated) infections as well. Alterations in immune functions that are induced by UVR are initiated by the absorption of light energy by chromophores and their transformation into photoproducts. Some of them are removed by repair mechanisms, others induce signal transduction pathways, whereas some exhibit cytotoxicity. The observable skin response may occur within minutes of light exposure (e.g. urticaria) or may take days (e.g. inhibition of contact hypersensitivity), or much longer periods to be expressed (e.g. tumors). Today, artificial UVR (phototherapy) is used in dermatology for induction of immunomodulation in many forms of autoimmune and/or hyperimmune responses in the skin.
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