Aster glehni Extract, Including Caffeoylquinic Acids as the Main Constituents, Induces PPAR ß/δ-Dependent Muscle-Type Change and Myogenesis in Apolipoprotein E Knockout Mice.

To probe the functions of Aster glehni (AG) extract containing various caffeoylquinic acids on dyslipidemia, obesity, and skeletal muscle-related diseases focused on the roles of skeletal muscle, we measured the levels of biomarkers involved in oxidative phosphorylation and type change of skeletal muscle in C2C12 cells and skeletal muscle tissues from apolipoprotein E knockout (ApoE KO) mice. After AG extract treatment in cell and animal experiments, western blotting, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were used to estimate the levels of proteins that participated in skeletal muscle type change and oxidative phosphorylation. AG extract elevated protein expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), phosphorylated 5'-AMP-activated protein kinase (p-AMPK), peroxisome proliferator-activated receptor beta/delta (PPARß/δ), myoblast determination protein 1 (MyoD), and myoglobin in skeletal muscle tissues. Furthermore, it elevated the ATP concentration. However, protein expression of myostatin was decreased by AG treatment. In C2C12 cells, increments of MyoD, myoglobin, myosin, ATP-producing pathway, and differentiation degree by AG were dependent on PPARß/δ and caffeoylquinic acids. AG extract can contribute to the amelioration of skeletal muscle inactivity and sarcopenia through myogenesis in skeletal muscle tissues from ApoE KO mice, and function of AG extract may be dependent on PPARß/δ, and the main functional constituents of AG are trans-5-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. In addition, in skeletal muscle, AG has potent efficacies against dyslipidemia and obesity through the increase of the type 1 muscle fiber content to produce more ATP by oxidative phosphorylation in skeletal muscle tissues from ApoE KO mice.

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

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.