Reversion of glucocorticoid-induced senescence and collagen synthesis decrease by LY294002 is mediated through p38 in skin.

Glucocorticoids (GCs) are the most common treatment for inflammatory skin disorders; however, they show several adverse side effects, including atrophy and collagen decrease following chronic treatment. In particular, transcription factors and p38 signaling for collagen synthesis have been shown to be suppressed by the active glucocorticoid receptor (GR). LY294002 (LY), a phosphoinositide 3-kinase (PI3K) inhibitor, has been reported to protect keratinocytes in epidermis against GC-induced hypoplasia; however, its protective effect in dermis remains unclear. Furthermore, clobetasol propionate (CP) is the most used commercial synthetic GC, yet studies on how CP causes side effects in dermal fibroblasts are limited. In this study, dermal atrophy was modeled using CP in human dermal fibroblasts (HDFs) and C57BL/6 mice. CP treatment significantly upregulated FK506 binding protein 5 (FKBP51), an atrophy marker (2.4 ± 0.25 and 3.3 ± 0.3 fold in in vitro and in vivo, respectively), phosphorylated GR (1.96 ± 0.08 and 2.29 ± 0.25 fold in in vitro and in vivo, respectively), decreased fibroblast proliferation (82.71 ± 1.95% in in vitro), reduced collagen synthesis (0.36 ± 0.05 and 0.3 ± 0.1 fold in in vitro and in vivo, respectively), and induced aging, all of which were reversed by LY treatment (from 1.43 ± 0.08 to 2.8 ± 0.12 fold) without showing growth inhibition and exerting the anti-inflammation of CP. Interestingly, the protective effect of LY was dose-dependently reversed by treatment with a p38 inhibitor and reached 2.9 ± 0.15 fold at dose 20 µM. Taken together, our results demonstrate that LY reduced CP-induced upregulation of the atrophy marker FKBP51, GR phosphorylation, and GR nuclear translocation via the activation of p38, whilst maintaining the anti-inflammatory effect of glucocorticoids.

Seven traditional Chinese herbal extracts fermented by Lactobacillus rhamnosus provide anti-pigmentation effects by regulating the CREB/MITF/tyrosinase pathway.

Skin pigmentation is resulted from several processes, such as melanin synthesis transportation and abnormal melanin accumulation in keratinocytes. Various studies have suggested that seven traditional Chinese herbal extracts from Atractylodes macrocephala, Paeonia lactiflora, Bletilla striata, Poria cocos, Dictamnus dasycarpus, Ampelopsis japonica and Tribulus terrestris (which we collectively named ChiBai), show several protective effects toward skin-related diseases. Lactobacillus rhamnosus, a lactic acid bacterium, has been reported to treat skin inflammation and atopic dermatitis. In this study, the broth produced by the cofermentation of ChiBai with Lactobacillus rhamnosus was studied for its effects on skin pigmentation through in vitro and in vitro experiments. In the in vitro experiments, we found that the fermented broth of ChiBai (FB-ChiBai) suppressed alpha-melanocyte stimulating hormone (α-MSH)-induced melanogenesis in B16F0 murine melanoma cells without any cytotoxicity at a concentration of 0.5%. FB-ChiBai significantly attenuated melanin production, tyrosinase activities and melanogenesis-related signaling pathways. Treatment with FB-ChiBai also reduced the nuclear translocation and promoter binding activities of MITF. In the in vivo experiments, FB-ChiBai was topically applied to the dorsal skin of C57BL/6J nude mice and concurrently irradiated with UVB, three times a week for 8 weeks. The results indicated that FB-ChiBai alleviated UVB-induced hyperpigmentation by reducing epidermal hyperplasia and inhibiting the CREB/MITF/tyrosinase pathway. In conclusion, our data indicated that the anti-melanogenic effects of FB-ChiBai are mediated by the inhibition of CREB/MITF/tyrosinase signaling pathway. The findings suggest that FB-ChiBai can protect against UV-B irradiation and that it might be used as an agent in cosmetic products to protect against UVB-induced hyperpigmentation.