UVA and UVB wavebands modulate expression ofFasLin mouse skin epidermis

Radiation Sources Providing Increased UVA/UVB Ratios Attenuate the Apoptotic Effects of the UVB Waveband UVA-Dose-Dependently in Hairless Mouse Skin

“…The modifying role played by UVA-induced HO activity suggests that critical signaling pathways may be affected, UVA Attenuates UVB-Induced Apoptosis perhaps underlying the UVA prevention of UVB-induced Fas upregulation that we have observed previously in the hairless mouse skin (Shen et al, 2000). In the studies of others, upregulation of HO-1 has rendered Jurkat T cells or pancreatic cells resistant to Fas-mediated apoptosis (Pileggi et al, 2001;Choi et al, 2004), and HO-1 gene transfer in a liver transplant model also prevented FasLmediated apoptosis (Ke et al, 2002).…”

“…It is relevant that both HO-1 and CO have been associated with antiinflammatory as well as antiapoptotic effects in several cellular and tissue models (Inguaggiato et al, 2001;Liu et al, 2003;Ryter and Otterbein, 2004;Hirota et al, 2005). Furthermore, we have previously shown in mice that UVA irradiation following UVB exposure has the ability to reduce the upregulation of cutaneous Fas ligand (FasL) expression resulting from the UVB irradiation (Shen et al, 2000). The Fas-FasL system is known to play a major role in inducing apoptosis, including sunburn cell formation in the epidermis (Hill et al, 1999).…”

Increased expression of Fas on human epidermal cells after in vivo exposure to single-dose ultraviolet (UV) B or long-wave UVA radiation

“…We have investigated changes over a short period of time, in normal human skin and after single‐dose UVB radiation, so these studies are not directly comparable. Contrasting data exist from studies on hairless mice where single‐dose UVB has been shown to upregulate epidermal FasL, 20 whereas animals receiving chronic UV irradiation from FS40 lamps showed a decrease in FasL expression 18 . It is not easy to identify the reason for these contrasting results, other than different light sources and thinner skin in mice.…”

“…No human studies of changes in epidermal FasL expression after UVA irradiation have been published. However, in hairless mice the expression of FasL on keratinocytes increases after in vivo single‐dose UVA, 20 and in vitro the expression of FasL on human T‐helper cells increases after single‐dose UVA 21 …”