IL-4 suppresses UVB-induced apoptosis in skin.
In this study, cutaneous role of IL-4 in UVB-induced apoptosis was investigated using transgenic mice with skin-specific expression of IL-4 (IL-4 Tg mice). The transgenic mice did not show any gross clinical abnormalities. However, epidermis was thickened and increased MHC class II positive cells were detected as well as enhanced expression of inflammatory cytokines such as IL-1 and TNF-alpha in skin. In addition, histological analysis revealed increased infiltration of lymphocytes, acanthosis, hyperkeratosis, and parakeratosis in skin of IL-4 Tg mice. The physiological effect of IL-4 overexpression in skin against environmental stimulus such as UVB was investigated by irradiating wild-type and IL-4 Tg mice with UVB followed by evaluation of apoptosis. The result demonstrated suppressed apoptosis in epidermis of IL-4 Tg mice compared with wild-type mice. To further assess anti-apoptotic function of IL-4 in keratinocytes, stable cell clones were made where IL-4 was constitutively overexpressed and examined for UVB-induced apoptosis. The results showed that apoptosis was remarkably decreased in IL-4 over-expressing cell clones compared with that in mock transfected cells. Collectively, data presented here shows that IL-4 has an inhibitory effect against UVB-induced apoptosis in keratinocytes, suggesting that IL-4 may be an important regulator in cutaneous immunity against UVB.
Hwang
Hayoung
H
Laboratory of Dermatology-Immunology, Catholic Research Institute of Medical Science, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
Choi
Soo-Young
SY
Kim
Tae Yoon
TY
D000818:Animals; D017209:Apoptosis / Q000235:genetics* / Q000528:radiation effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism / Q000528:radiation effects; D015847:Interleukin-4 / Q000235:genetics / Q000502:physiology*; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects; D051379:Mice; D008822:Mice, Transgenic; D009928:Organ Specificity; D012867:Skin / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
D051017:Apoptosis Regulatory Proteins; D015847:Interleukin-4