Protective Activity and Underlying Mechanism of Ginseng Seeds against UVB-Induced Damage in Human Fibroblasts.

Ginseng seeds are rich in phytosterols, ginsenosides, and fatty acids, and can therefore be used in skincare to delay the aging process. Ginseng seed embryo (GSE) and ginseng seed coat (GSC) were separated from ginseng seeds (Panax ginseng Meyer). This study evaluated the protective activity and underlying mechanism of GSE and GSC on UVB irradiation-induced skin photoaging using Hs68 cells. Their bioactive compounds, including phytosterols, ginsenosides, tocopherols, tocotrienols, and fatty acids were determined by HPLC and GC. The levels of reactive oxygen species, matrix metalloproteinases (MMPs), and collagen levels were measured in human dermal fibroblast cell line, Hs68 cells. The antioxidant capacity and contents of total polyphenols and flavonoids were higher in GSC than those in GSE. Linoleic acid was the major fatty acid in both GSE and GSC. GSE and GSC treatment alleviated UVB-induced increase of reactive oxygen species (ROS), matrix metalloproteinase (MMP)-1, and MMP-3, resulting in reduced collagen degradation. Increased UVB-mediated phosphorylation of mitogen activated protein kinase (MAPK) and activator protein-1 (AP-1) was inhibited by GSE and GSC treatment. Moreover, GSE and GSC effectively upregulated transforming growth factor-ß (TGF-ß) 1 levels. It was found that ginseng seeds regulate the expression of TGF-ß/Smad and MAPK/AP-1 pathways. Ginseng seeds contain various bioactive compounds and have protective activity against UVB-induced skin photoaging. Therefore, ginseng seeds have the potential for use in cosmeceutical preparations.

Effect of Deglycosylated Rutin by Acid Hydrolysis on Obesity and Hyperlipidemia in High-Fat Diet-Induced Obese Mice.

The present study evaluated the effects of acid-treated rutin on hyperlipidemia and obesity in high-fat diet (HFD)-induced obese mice. The mice consumed a HFD with or without acid-treated rutin for 7 weeks. Body weight gain considerably decreased, by approximately 33%, in the acid-treated rutin (AR) and quercetin (Q) groups compared to that in the HFD group. The adipocytes' size in epididymal fat in AR and Q groups was significantly reduced compared to that in the HFD group (p < 0.05). Treatment with AR decreased the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol compared to the HFD group. In particular, administration of AR significantly decreased serum triglyceride (36.82 mg/dL) by 46% compared to HFD (69.30 mg/dL). The AR group also showed significantly decreased atherogenic indices and cardiac risk factors. These results suggest that deglycosylated rutin generated by acid treatment enhances the anti-obesity and hypolipidemic effects in obese mice, and provides valuable information for improving the functional properties of glycosidic flavonoids.

CUEDC2 controls osteoblast differentiation and bone formation via SOCS3-STAT3 pathway.

The CUE domain-containing 2 (CUEDC2) protein plays critical roles in many biological processes, such as the cell cycle, inflammation, and tumorigenesis. However, whether CUEDC2 is involved in osteoblast differentiation and plays a role in bone regeneration remains unknown. This study investigated the role of CUEDC2 in osteogenesis and its underlying molecular mechanisms. We found that CUEDC2 is expressed in bone tissues. The expression of CUEDC2 decreased during bone development and BMP2-induced osteoblast differentiation. The overexpression of CUEDC2 suppressed the osteogenic differentiation of precursor cells, while the knockdown of CUEDC2 showed the opposite effect. In vivo studies showed that the overexpression of CUEDC2 decreased bone parameters (bone volume, bone area, and bone mineral density) during ectopic bone formation, whereas its knockdown increased bone volume and the reconstruction percentage of critical-size calvarial defects. We found that CUEDC2 affects STAT3 activation by regulating SOCS3 protein stability. Treatment with a chemical inhibitor of STAT3 abolished the promoting effect of CUEDC2 silencing on osteoblast differentiation. Together, we suggest that CUEDC2 functions as a key regulator of osteoblast differentiation and bone formation by targeting the SOCS3-STAT3 pathway. CUEDC2 manipulation could serve as a therapeutic strategy for controlling bone disease and regeneration.

The primary cilium directs osteopontin-induced migration of mesenchymal stem cells by regulating CD44 signaling and Cdc42 activation.

The primary cilium acts as a sensory organelle with diverse receptors and ion channels to detect extracellular cues and regulate cellular functions, including cell migration. The migration of mesenchymal stem cells (MSCs) to bone remodeling sites is important for bone homeostasis. Recently, we have suggested that osteopontin (OPN) is a significant chemoattractant in MSC migration to bone remodeling sites. The objective of this study was to determine whether the primary cilium acts as a chemoattractant sensory unit to detect OPN cues and control MSC migration. We found that the loss of primary cilium induced by silencing of IFT88 reduced OPN-induced migration of MSCs. The effect of IFT88 silencing on cellular attachment, spreading, and proliferation was negligible. The loss of primary cilium did not affect the level of integrinß1 or CD44, two known receptors for OPN. Interestingly, CD44 was localized to the primary cilium by OPN stimulus. Knockdown of IFT88 or CD44 dysregulated OPN-induced signaling activation and abolished OPN-induced Cdc42 activation. Our findings suggest that the primary cilium acts as a chemoattractant sensor for OPN to regulate MSC migration by controlling not only CD44-mediated OPN signaling, but also Cdc42-mediated actin cytoskeleton rearrangement.

Fenofibrate induces PPARα and BMP2 expression to stimulate osteoblast differentiation.

The peroxisome proliferator-activated receptor (PPAR)-α agonist fenofibrate is used as a lipid-lowering agent to reduce cholesterol and triglyceride in blood. In this study, we investigated whether fenofibrate affects osteoblast differentiation of osteogenic precursor cells. Quantitative real-time PCR and alkaline phosphatase (ALP) staining assays revealed that fenofibrate can enhance the osteoblast differentiation of C3H10T1/2 and MC3T3-E1 cells. In contrast with fenofibrate, the PPARγ agonist rosiglitazone decreased or did not affect the expression of osteogenic genes in these cells. Fenofibrate dose- and time-dependently increased PPARα expression, and concomitantly increased the expression of bone morphogenetic protein 2 (BMP2). Knockdown of PPARα abolished fenofibrate-induced BMP2 expression, activity of the BMP2 promoter gene, and calcium deposition. The chromatin immunoprecipitation assay demonstrated that fenofibrate increased BMP2 expression by inducing direct binding of PPARα to the BMP2 promoter region. Taken together, we suggest that fenofibrate has a stimulatory effect on osteoblast differentiation via the elevation of PPARα levels and the PPARα-mediated BMP2 expression. Our findings provide fenofibrate as a useful agent for controlling hypercholesterolemic patients with osteoporosis.

Conversion of Rutin to Quercetin by Acid Treatment in Relation to Biological Activities.

De-glycosylation could be an important process for enhancing the biological activities of flavonoids. In this study we investigated de-glycosylation of rutin by acid treatment by comparing hydrolysis of rutin to quercetin with two different solvents and acid concentrations. Antioxidant activity was measured using chemical methods and biological activities were examined in cell-based systems. Rutin hydrolysis occurred more rapidly when 80% ethanol was used as the reaction solvent (as compared to water), and the rate of hydrolysis accelerated as acid concentrations increased. In reactions of rutin with 0.5 M HCl in 80% ethanol for 3 h, almost all the rutin was converted into quercetin. 2,2-Diphenyl-1-picrylhydrazyl, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging activities, and reducing powers were correlated with conversion rate. Protective activity in HepG2 cells, anti-inflammatory activity in RAW264.7 cells, and antiadipogenic activity were increased with increased conversion of rutin to quercetin. This study suggests that de-glycosylation of glycoside flavonoids may increase physiological activity and, therefore, enhance its use in various fields.

Nobiletin Inhibits Hepatic Lipogenesis via Activation of AMP-Activated Protein Kinase.

We aimed to investigate the effects of nobiletin on hepatic lipogenesis in high glucose-induced lipid accumulation in HepG2 cells. Nobiletin, a citrus polymethoxyflavonoid with six methoxy groups, is present abundantly in the peels of citrus fruits. HepG2 cells were incubated in Dulbecco's modified Eagle's medium containing high glucose (25 mM) and subsequently treated with nobiletin at different concentrations (5, 25, and 50 µM). Results showed that nobiletin markedly inhibited high glucose-induced hepatic lipid accumulation in HepG2 cells. In addition, it reduced the protein expression of lipogenic factors, including sterol regulatory element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS). Nobiletin significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. Pretreatment with compound C, an AMPK inhibitor, abolished the inhibitory effects of nobiletin on SREBP-1c and FAS expression. These results suggested that nobiletin might attenuate high glucose-induced lipid accumulation in HepG2 hepatocytes via modulation of AMPK signaling pathway. Therefore, nobiletin might be useful for the prevention and treatment of nonalcoholic fatty liver diseases.

Nobiletin Attenuates the Inflammatory Response Through Heme Oxygenase-1 Induction in the Crosstalk Between Adipocytes and Macrophages.

Crosstalk between adipocytes and macrophages has been suggested to play a crucial role in metabolic disorders such as obesity, insulin resistance, and type 2 diabetes. The objective of this study was to evaluate the effect of nobiletin on the interaction between adipocytes and macrophages. The results showed that nobiletin significantly and dose-dependently inhibited the secretion of inflammatory mediators, such as nitric oxide (NO), tumor necrosis factor (TNF-α), and monocyte chemoattractant protein (MCP)-1, in a coculture of adipocytes and macrophages. The expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), in differentiated 3T3-L1 cells cocultured in transwell system was blocked by nobiletin. Nobiletin also downregulated the expression of inducible NO synthase in cocultured differentiated RAW264.7 cells. Furthermore, heme oxygenase-1 (HO-1) was significantly induced by nobiletin treatment in both cell types, and small interfering (si) RNA-mediated knockdown of HO-1 significantly recovered the inhibitory effects of nobiletin on the NO production in cocultured cells. These results suggest that nobiletin exerts anti-inflammatory effects on the crosstalk between adipocytes and macrophages by inducing HO-1. Nobiletin may have potential for the prevention of obesity-related metabolic diseases.

PHF20 positively regulates osteoblast differentiation via increasing the expression and activation of Runx2 with enrichment of H3K4me3.

Plant homeodomain finger protein 20 (PHF20), a methyl lysine effector protein, is a component MOF-NSL lysine acetyltranferase complex. Global deletion of PHF20 has shown spinal bone defects and reduced skeletal formation. However, the molecular basis of PHF20 involved in skeletal development has not been elucidated yet. The objective of this study was to determine the role of PHF20 in osteoblast differentiation and mineralization. Expression of PHF20 was gradually increased during osteoblast differentiation. Overexpression of PHF20 enhanced ALP activity and mineralized nodule formation as well as the expression of osteogenic markers including Runx2. In contrast, inhibition of PHF20 expression reduced osteoblast differentiation and mineralization. Mechanistically, PHF20 increased the promoter activity of osteogenic genes including Og2, Alp, and Bsp through direct association with Runx2. Moreover, PHF20 increased the enrichment of H3K4me3 on the promoter of Runx2 followed by increased Runx2 promoter activity. Interestingly, Bix-01294, a histone methylation inhibitor, decreased mineralized nodule formation through decreasing the levels of H3K4me3 and Runx2. Overexpression of PHF20 restored the Bix-01294 effects. Taken together, these results indicate that methyl lysine-binding protein PHF20 might be a novel regulator of osteoblast differentiation.

Inhibitory effect of esculetin on free-fatty-acid-induced lipid accumulation in human HepG2 cells through activation of AMP-activated protein kinase.

This study aimed to determine the lipid-lowering effect of esculetin (6,7-dihydroxycoumarin), a coumarin derivative, using a cell model of steatosis induced by a mixture of free fatty acids (FFAs). Esculetin dose-dependently inhibited intracellular lipid accumulation by down-regulating the protein expression of lipogenic genes such as sterol regulatory element-binding protein-1c (SREBP1c) and fatty acid synthase (FAS) in FFAs-induced HepG2 cells. Moreover, esculetin significantly elevated the activation of the adenosine monophosphate-activated protein kinase (AMPK) signaling pathways in HepG2 hepatocytes. The anti-lipogenic effects of esculetin mediated by AMPK activation were abolished when FFAs-induced HepG2 cells were treated with a specific inhibitor of AMPK, i.e., compound C. These results suggest that esculetin attenuates hepatic lipid accumulation by inhibiting lipogenesis through the modulation of AMPK signaling pathway on FFAs-induced steatosis in HepG2 cells and may be used for the prevention of nonalcoholic fatty liver disease (NAFLD).

Inhibitory Effects of Butein on Adipogenesis through Upregulation of the Nrf2/HO-1 Pathway in 3T3-L1 Adipocytes.

Butein is reported to have many biological effects, including anti-fibrogenic, anti-cancer, and anti-inflammatory activities. This study investigated the effects of butein on adipocyte differentiation and the Nrf2/heme oxygenase-1 (HO-1) pathway's involvement in its anti adipogenic mechanism. Butein treatment reduced protein expression of key adipogenic transcription factors such as CCAAT-enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ). At a concentration of 5, 10, and 25 µM butein, PPARγ was decreased by 78.8, 68.3, and 31.4% and C/EBPα by 87.3, 71.7, and 42.1%, respectively. Butein also increased Nrf2 and HO-1 protein expression in a dose-dependent manner. Treatment with zinc protoporphyrin, a specific HO-1 inhibitor, abolished the inhibitory effects of butein on adipogenic transcription factor protein expression. Therefore, butein inhibits adipogenesis, at least partially, through upregulation of the Nrf-2/HO-1 signaling pathway in 3T3-L1 adipocytes.

Effect of defatted pepper (Capsicum annuum L.) seed extracts on high-fat diet-induced obesity in C57BL/6J mice.

This study investigated the effect of defatted pepper seed ethanolic extract (DPSE) on high-fat diet-induced obesity in C57BL/6J mice. The mice were fed a normal diet (ND), high fat diet (HFD), or HFD in combination with DPSE (100 and 200mg/kg body weight) for 7 weeks. Supplementing the HFD of mice with DPSE significantly decreased body weight gain and food efficiency ratio induced by HFD. The amount of epididymal fat and size of adipocytes were also dramatically reduced by DPSE supplementation. Although no statistical significance was found between the HFD and HFD plus DPSE groups in plasma fat deposition, liver weight, and hepatic cholesterol contents were significantly reduced in the DPSE-treated group. In conclusion, these results suggest that DPSE could prevent obesity and adiposity. These effects may be important in developing therapeutic agents against obesity in future.