Aster glehni Extract Containing Caffeoylquinic Compounds Protects Human Keratinocytes through the TRPV4-PPARδ-AMPK Pathway.

Yong-Jik Lee,Yoon-Mi Han,Yoo-Na Jang,Hyun-Min Kim,Changbae Jin,Hyoung Ja Kim,Hong Seog Seo

doi:10.1155/2018/9616574

Abstract

Aster glehni (AG) has been used in cooking and as a medicine to treat various diseases for over hundreds of years in Korea. To speculate the protective effects of AG on skin barrier, we estimated the protein levels of biomarkers related to skin barrier protection in human keratinocytes, HaCaT cells treated with sodium dodecyl sulfate (SDS), or 2,4-dinitrochlorobenzene (DNCB). The protein levels for keratin, involucrin, defensin, tumor necrosis factor alpha (TNFα), peroxisome proliferator-activated receptor delta (PPARδ), 5′ adenosine monophosphate-activated protein kinase (AMPK), serine palmitoyltransferase long chain base subunit 2 (SPTLC2), and transient receptor potential cation channel subfamily V member 4 (TRPV4) were evaluated using western blotting or immunocytochemistry in HaCaT cells. AG extract increased the protein levels of PPARδ, phosphorylated AMPK, SPTLC2, keratin, involucrin, and defensin compared to the SDS or DNCB control group. However, TNFα expression increased by SDS or DNCB was decreased with AG extract. The order of action of each regulatory biomarker in AG pathway was identified TRPV4→PPARδ→AMPK from antagonist and siRNA treatment studies. AG can ameliorate the injury of keratinocytes caused by SDS or DNCB through the sequential regulation of TRPV4→PPARδ→AMPK pathway.

Highlights

The skin, called integument, consists of three major layers, namely epidermis, dermis, and hypodermis
Through further analysis, it was confirmed that the ethyl acetate fraction extracted from Aster glehni (AG) mainly consists of caffeoylquinic compounds of seven kinds which consisted of 5-caffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-epi-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid (3,5DCQA), 4,5-dicaffeoylquinic acid, methyl 3,4-dicaffeoylquinate, and methyl 4,5-dicaffeoylquinate (Figure 1)
We estimated the protein levels of peroxisome proliferator-activated receptor δ (PPARδ), AMPK, and SPTLC2 in HaCaT cells treated with Sodium dodecyl sulfate (SDS) or DNCB along with AG

Summary

Introduction

The skin, called integument, consists of three major layers, namely epidermis, dermis, and hypodermis (subcutis). The epidermis is the outer region of the skin and has four layers—stratum basale, stratum spinosum, stratum granulosum, and stratum corneum (the outermost thin layer of the skin). The permeability barrier of skin is provided by stratum corneum and is composed of corneocytes, cornified envelope, corneodesmosome, and intercorneocyte lipid. The cornified envelope comprises transglutaminase, involucrin, loricrin, and filaggrin, and it serves as a complete permeability barrier through the formation of the multilayered structure of intercorneocyte lipid. The main functions of the skin are to prevent the loss of body fluids, attack of toxins, and invasion of pathogens [1,2,3]. The impairment of skin permeability barrier function is not a simple mechanical destruction of the outer layer of the skin. Sodium dodecyl sulfate (SDS) is generally known as a skin

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