Potential Role of Cytosolic RNA Sensor MDA5 as an Inhibitor for Keratinocyte Differentiation in the Pathogenesis of Psoriasis

Background@#Psoriasis is a chronic inflammatory skin disease. The etiology of psoriasis is not fully understood, but the genetic background is considered to be the most important factor. To date, many psoriasis-related genes have been discovered, but the role of many important genes has not been well understood. @*Objective@#The purpose of this study is to uncover possible roles of MDA5 in psoriasis. @*Methods@#Expression of MDA5 was investigated using immunohistochemistry. Then, MDA5 was overexpressed in keratinocytes using a recombinant adenovirus. @*Results@#As a result of immunohistochemical staining, the expression of MDA5 was significantly increased in the epidermis of psoriasis compared to normal skin. Similarly, the expression of MDA5 was increased in imiquimod-induced psoriasiform dermatitis model. In cultured keratinocytes, toll-like receptor 3 agonist poly(I:C) induced expression of MDA5 at both mRNA and protein levels. When MDA5 was overexpressed using a recombinant adenovirus, poly(I:C)-induced cytokine expression was significantly increased. Finally, MDA5 overexpression significantly inhibited calcium-induced differentiation of keratinocytes. @*Conclusion@#These results suggest that MDA5 increases in psoriasis and negatively regulates keratinocyte differentiation.

Potential Role of Cytosolic RNA Sensor MDA5 as an Inhibitor for Keratinocyte Differentiation in the Pathogenesis of Psoriasis

Background@#Psoriasis is a chronic inflammatory skin disease. The etiology of psoriasis is not fully understood, but the genetic background is considered to be the most important factor. To date, many psoriasis-related genes have been discovered, but the role of many important genes has not been well understood. @*Objective@#The purpose of this study is to uncover possible roles of MDA5 in psoriasis. @*Methods@#Expression of MDA5 was investigated using immunohistochemistry. Then, MDA5 was overexpressed in keratinocytes using a recombinant adenovirus. @*Results@#As a result of immunohistochemical staining, the expression of MDA5 was significantly increased in the epidermis of psoriasis compared to normal skin. Similarly, the expression of MDA5 was increased in imiquimod-induced psoriasiform dermatitis model. In cultured keratinocytes, toll-like receptor 3 agonist poly(I:C) induced expression of MDA5 at both mRNA and protein levels. When MDA5 was overexpressed using a recombinant adenovirus, poly(I:C)-induced cytokine expression was significantly increased. Finally, MDA5 overexpression significantly inhibited calcium-induced differentiation of keratinocytes. @*Conclusion@#These results suggest that MDA5 increases in psoriasis and negatively regulates keratinocyte differentiation.

Novel Mechanism of Action of Dutasteride for Inducing Hair Growth in Patients with Female-Pattern Hair Loss / 대한피부과학회지

Background@#Female-pattern hair loss (FPHL) is a common hair loss disorder in women. The various treatments include topical minoxidil and 17α-estradiol, as well as oral anti-androgens. However, the clinical efficacy of 5α -reductase inhibitors remains controversial. @*Objective@#We evaluated the clinical utility of dutasteride in FPHL patients and how dutasteride promotes hair growth. @*Methods@#We evaluated hair follicle density and thickness before and after oral dutasteride treatment in 24 patients with FPHL. We measured β-catenin activity in primary cultures of human dermal papilla cells (DPCs) using the TOP Flash reporter assay and Western blotting. The expression levels of genes promoting hair growth were quantitatively assessed using quantitative polymerase chain reaction (Q-PCR). @*Results@#The mean vertex hair density increased significantly from 67±14 to 76±13/cm2 (p=0.001) and the mean occipital hair density increased from 89±11 to 94±13/cm2 (p=0.012) after dutasteride treatment. However, the mean hair thickness did not increase. When DPCs were treated with dutasteride, TOP Flash activity increased in a dose-dependent manner, and the protein level of non-phosphorylated (active) β-catenin also increased. The mRNA level of vascular endothelial growth factor increased, but the mRNA levels of the keratinocyte growth factor, insulin growth factor-1, and Noggin were not affected by dutasteride. @*Conclusion@#This study shows a novel mechanism of dutasteride in promoting hair growth and provides support for the possible clinical application of 5α-reductase inhibitors for the treatment of FPHL.

Isoginkgetin Inhibits Insulin-Like Growth Factor-1-Induced Sebum Production in Cultured Human Sebocytes

No abstract available.

A Novel Compound Rasatiol Isolated from Raphanus sativus Has a Potential to Enhance Extracellular Matrix Synthesis in Dermal Fibroblasts

BACKGROUND: The fibrous proteins of extracellular matrix (ECM) produced by dermal fibroblast contributes to the maintenance of connective tissue integrity. OBJECTIVE: This study is carried out to identify the bioactive ingredient from natural products that enhances ECM production in dermal fibroblasts. METHODS: Bioassay-directed fractionation was used to isolate the active ingredient from natural extracts. The effects of rasatiol (isolated from Raphanus sativus) on ECM production in primary cultured human dermal fibroblasts was investigated by enzyme linked immunosorbent assay and western blot analysis. RESULTS: Rasatiol accelerated fibroblast growth in a dose-dependent manner and increased the production of type 1 collagen, fibronectin and elastin. Phosphorylation of p42/44 extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and Akt was remarkably increased by rasatiol, indicating that enhanced ECM production is linked to the activation of intracellular signaling cascades. CONCLUSION: These results indicate that rasatiol stimulates the fibrous components of ECM production, and may be applied to the maintenance of skin texture.

A Novel Compound Rasatiol Isolated from Raphanus sativus Has a Potential to Enhance Extracellular Matrix Synthesis in Dermal Fibroblasts

BACKGROUND: The fibrous proteins of extracellular matrix (ECM) produced by dermal fibroblast contributes to the maintenance of connective tissue integrity. OBJECTIVE: This study is carried out to identify the bioactive ingredient from natural products that enhances ECM production in dermal fibroblasts. METHODS: Bioassay-directed fractionation was used to isolate the active ingredient from natural extracts. The effects of rasatiol (isolated from Raphanus sativus) on ECM production in primary cultured human dermal fibroblasts was investigated by enzyme linked immunosorbent assay and western blot analysis. RESULTS: Rasatiol accelerated fibroblast growth in a dose-dependent manner and increased the production of type 1 collagen, fibronectin and elastin. Phosphorylation of p42/44 extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and Akt was remarkably increased by rasatiol, indicating that enhanced ECM production is linked to the activation of intracellular signaling cascades. CONCLUSION: These results indicate that rasatiol stimulates the fibrous components of ECM production, and may be applied to the maintenance of skin texture.

Cedrol Enhances Extracellular Matrix Production in Dermal Fibroblasts in a MAPK-Dependent Manner

BACKGROUND: The extracellular matrix (ECM) produced by dermal fibroblasts supports skin structure, and degradation and/or reduced production of ECM are the main causes of wrinkle formation. OBJECTIVE: The aim of this study was to identify the active ingredient that enhances ECM production in dermal fibroblasts. METHODS: Polarity-based fractionation was used to isolate the active ingredient from natural extracts, and the effects of cedrol (isolated from Pterocarpus indicusirginia) on ECM production in cultured human dermal fibroblasts was investigated by reverse transcription-polymerase chain reaction, enzyme linked immunosorbent assay, and Western blot analysis. RESULTS: Cedrol accelerated fibroblast growth in a dose-dependent manner and increased the production of type 1 collagen and elastin. Phosphorylation of p42/44 extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and Akt was markedly increased by cedrol, indicating that enhanced ECM production is linked to activation of intracellular signaling cascades. CONCLUSION: These results indicate that cedrol stimulates ECM production, with possible applications to the maintenance of skin texture.

Stimulation of the Extracellular Matrix Production in Dermal Fibroblasts by Velvet Antler Extract

BACKGROUND: Fibroblasts produce many components of the extracellular matrix (ECM) and so they contribute to the maintenance of connective tissue integrity. OBJECTIVE: The aim of this study is to evaluate the effect of velvet antler extract (VAE) on the ECM production of dermal fibroblasts cultured in vitro. METHODS: Primary cultured human dermal fibroblasts were treated with VAE, and then the ECM production was determined by RT-PCR, ELISA and Western blot analysis. Furthermore, the change of gene expression according to VAE treatment was evaluated by cDNA microarray. RESULTS: VAE accelerated the growth of fibroblasts in a dose-dependent manner. VAE increased the production of several ECM components, including type 1 collagen, fibronectin and elastin. In line with these results, the phosphorylations of p42/44 ERK and p38 mitogen-activated protein kinase were markedly increased by VAE, suggesting that the enhancement of ECM production may be linked to the activation of intracellular signaling cascades. VAE also significantly increased cell migration on an in vitro scratch wound test. In cDNA microarray, many genes related with connective tissue integrity were identified to be up-regulated by VAE. CONCLUSION: These results suggest that VAE has a potential to stimulate ECM production, and VAE may be applicable for maintaining the skin's texture.