ABSTRACT
Alopecia is a distressing condition caused by the dysregulation of anagen, catagen, and telogen in the hair cycle. Dermal papilla cells (DPCs) regulate the hair cycle and play important roles in hair growth and regeneration. Myristoleic acid (MA) increases Wnt reporter activity in DPCs. However, the action mechanisms of MA on the stimulation of anagen signaling in DPCs is not known. In this study, we evaluated the effects of MA on anagen-activating signaling pathways in DPCs. MA significantly increased DPC proliferation and stimulated the G2/M phase, accompanied by increasing cyclin A, Cdc2, and cyclin B1. To elucidate the mechanism by which MA promotes DPC proliferation, we evaluated the effect of MA on autophagy and intracellular pathways. MA induced autophagosome formation by decreasing the levels of the phospho-mammalian target of rapamycin (phospho-mTOR) and increasing autophagy-related 7 (Atg7) and microtubule-associated protein 1A/1B-light chain 3II (LC3II). MA also increased the phosphorylation levels of Wnt/β-catenin proteins, such as GSK3β ( Ser9 ) and β-catenin (Ser 552 and Ser675 ). Treatment with XAV939, an inhibitor of the Wnt/β-catenin pathway, attenuated the MA-induced increase in β-catenin nuclear translocation. Moreover, XAV939 reduced MA-induced effects on cell cycle progression, autophagy, and DPC proliferation. On the other hand, MA increased the levels of phospho (Thr202 /Tyr204 )-extracellular signal regulated kinases (ERK). MA-induced ERK phosphorylation led to changes in the expression levels of Cdc2, Atg7 and LC3II, as well as DPC proliferation. Our results suggest that MA promotes anagen signaling via autophagy and cell cycle progression by activating the Wnt/β-catenin and ERK pathways in DPCs.
ABSTRACT
Ultraviolet B (UVB) radiation is harmful to the skin and induces cytokine release from keratinocytes leading toinflammatory skin disorders. Previous studies have shown that chronic exposure to UVB radiation increases tumornecrosis factor (TNF)-α and interleukin (IL)-6 secretion through various signaling pathways, resulting in skininflammation and increased risk of skin cancer. The present study was undertaken to investigate the protective effectsof Rhododendron weyrichii flower (RWF) extracts against UVB damage of immortalized human keratinocytes(HaCaT). To determine the anti-inflammatory effects of RWF, we examined UVB-induced proinflammatory cytokineproduction in HaCaT cells in the presence or absence of RWF extract, using enzyme-linked immunosorbent assay(ELISA). The results indicated that the RWF extract inhibited the production of proinflammatory molecules suchas IL-6 and TNF-α, but not IL-8, in UVB-irradiated HaCaT cells. These results demonstrate that RWF potentiallyprotects against UVB-induced skin inflammation. In addition, using high-performance liquid chromatography (HPLC)fingerprinting, kaempferol (0.335 ppm) and astragalin (2.569 ppm) were identified and quantified as RWF extractconstituents. Moreover, we tested the potential application of RWF extracts as a cosmetic treatment by performinghuman skin primary irritation tests. In these tests, the RWF extracts did not induce adverse reactions. Based on theseresults, we suggest that RWF extracts be considered anti-inflammatory candidates for pharmaceutical and/or cosmeticapplications.
ABSTRACT
Objective: To investigate the anti-inflammatory effects of Jeju seaweeds on macrophage RAW 264.7 cells under lipopolysaccharide (LPS) stimulation. Methods: Ethyl acetate fractions were prepared from five different types of Jeju seaweeds, Dictyopteris divaricata (D. divaricata), Dictyopteris prolifera (D. prolifera), Prionitis cornea (P. cornea), Grateloupia lanceolata (G. lanceolata), and Grateloupia filicina (G. filicina). They were screened for inhibitory effects on proinflammatory mediators and cytokines such as nitric oxide (NO), prostaglandin E
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the anti-inflammatory effects of Jeju seaweeds on macrophage RAW 264.7 cells under lipopolysaccharide (LPS) stimulation.</p><p><b>METHODS</b>Ethyl acetate fractions were prepared from five different types of Jeju seaweeds, Dictyopteris divaricata (D. divaricata), Dictyopteris prolifera (D. prolifera), Prionitis cornea (P. cornea), Grateloupia lanceolata (G. lanceolata), and Grateloupia filicina (G. filicina). They were screened for inhibitory effects on proinflammatory mediators and cytokines such as nitric oxide (NO), prostaglandin E2, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6).</p><p><b>RESULTS</b>Our results revealed that D. divaricata, D. prolifera, P. cornea, G. lanceolata, and G. filicina potently inhibited LPS-stimulated NO production (IC50 values were 18.0, 38.36, 38.43, 32.81 and 37.14 µg/mL, respectively). Consistent with these findings, D. divaricata, D. prolifera, P. cornea, and G. filicina also reduced the LPS-induced and prostaglandin E2 production in a concentration-dependent manner. Expectedly, they suppressed the expression of inducible NO synthase and cyclooxygenase-2 at the protein level in a dose-dependent manner in the RAW 264.7 cells, as determined by western blotting. In addition, the levels of TNF-α and IL-6, released into the medium, were also reduced by D. divaricata, D. prolifera, P. cornea, G. lanceolata, and G. filicina in a dose-dependent manner (IC50 values for TNF-α were 16.11, 28.21, 84.27, 45.52 and 74.75 µg/mL, respectively; IC50 values for IL-6 were 37.35, 80.08, 103.28, 62.53 and 84.28 µg/mL, respectively). The total phlorotannin content was measured by the Folin-Ciocalteu method and expressed as phloroglucinol equivalents. The content was 92.0 µg/mg for D. divaricata, 151.8 µg/mg for D. prolifera, 57.2 µg/mg for P. cornea, 53.0 µg/mg for G. lanceolata, and 40.2 µg/mg for G. filicina.</p><p><b>CONCLUSIONS</b>Thus, these findings suggest that Jeju seaweed extracts have potential therapeutic applications for inflammatory responses.</p>