Decreased Levels of Covalently Bound Ceramide Are Associated with Ultraviolet B-Induced Perturbation of the Skin Barrier

Abstract

Although ultraviolet B (UVB) irradiation perturbs the skin barrier, little is known about the mechanism(s) with respect to the metabolism of ceramide (Cer). We examined changes in intercellular lipids in murine stratum corneum following UVB irradiation. A single UVB (75 mJ per cm(2)) irradiation caused a significant increase in transepidermal water loss, which plateaued at day 4. In parallel, covalently bound Cer was significantly decreased with the greatest decrease at days 3-4. In contrast, the levels of other free, non-bound lipids (including Cer or acylceramides) were significantly increased for Cer, or remained unchanged at day 4 compared with non-irradiated controls. RT-PCR analysis demonstrated a significant decrease in mRNA encoding transglutaminase-1 (TGase1). The peak occurred 2-4 d after a single UVB irradiation, a time when covalently bound Cer was significantly downregulated in concert with the disruption of the skin barrier. Furthermore, UVB-induced epidermal hyperplasia occurred to the greatest extent between 2 and 4 d following UVB irradiation. These results suggest that decreases in covalently bound Cer in the stratum corneum are mediated via the downregulation of TGase-1 as well as by the rapid induction of epidermal hyperplasia, which is attributable to the perturbation of the skin barrier induced by UVB irradiation.

Age-Related Changes in Male Skin: Quantitative Evaluation of One Hundred and Fifty Male Subjects

“…These localization-dependent differences are probably influenced by the higher sun exposure of the face and neck. This presumption was confirmed by Liu et al [31], who showed that cumulative sun exposure does reduce SC hydration, probably due to a UVB-induced downregulation of epidermal ceramides, fillagrins and aquaporins [32,33,34,35]. …”

An Innovative Complex of Benzene-Poly-Carboxylic Acid and Molybdenum, for Prevention and Treatment of Radiation Dermatitis

“…Radiotherapy induced skin dermatitis exists in an acute and a chronic form [21,22]. In this study we use a high single radiation dose of 30 Gy in order to cause severe skin dermatitis.…”

“…Irradiation-induced dermatitis represents one of the most important dose limiting factors in radiotherapy [21,22]. In the present study we are focusing on the acute form of radiotherapy induced skin dermatitis, which normally develops within a few weeks after exposure to a high dose of ionizing radiation.…”

Epidermal Barrier: Negative Changes in Atopic Dermatitis and Positive Changes Induced by Short-term Suberythemal Ultraviolet B Irradiation

“…However, a closer look at the result showed that the ratio of CER [EOH] to CER [AS] was slightly increased after UVB irradiation. This shows an interesting potential of UVB irradiation on improving the average Cer chain length, even at a dose known to disrupt the skin barrier [21]. Further studies to investigate the effectiveness of short-term suberythemal UVB on average CER chain length in AD patients are required.…”

“…In addition, the highly upregulated sphingomyelin deacyclase may also cause a CER deficiency as a result of competition with β-GlcCerase and sphingomyelinase for their respective substrates, sphingomyelin and glucosylceramide [19]. Downregulation of the de novo synthesis of CER in AD [20], possibly due to the decreased expression of Serine Palmitoyltransferase (SPT) [21], may also account for the decreased CER in AD. There is also a reduced amount of ω-hydroxyceramide bound to the cornified envelope, also called covalently bound CER, possibly due to the reduced expression of involucrin in AD [18,20].…”