Myung-Gyou Kim

Osteogenic Activity of Collagen Peptide via ERK/MAPK Pathway Mediated Boosting of Collagen Synthesis and Its Therapeutic Efficacy in Osteoporotic Bone by Back-Scattered Electron Imaging and Microarchitecture Analysis

Collagen hydrolysate (CH) has been reported to exhibit a positive effect on bone. In the present study, the in vitro effects of CH (<3 kDa) were examined and the in vivo experiments confirmed the positive effects of CH in ovariectomized (OVX) rats. Bone mineral density (BMD) was examined by DXA analysis. Scanning electron microscopic analysis and quantitative 3D-color backscattered electrons imaging analysis were performed on the lumbar vertebrae. CH increased osteoblastic cell proliferation and alkaline phosphatase activity in a dose-dependent manner. Collagen synthesis and collagen, type1, alpha1 (COL1A1) gene expression were also increased by CH treatment. Furthermore, CH-induced COL1A1 gene expression was completely abolished by extracellular signal-regulated kinase (ERK) inhibitor, suggesting the involvement of ERK/MAPK signaling for transcriptional effects on COL1A1 expression. OVX rats supplemented with CH showed osteoprotective effects as the BMD levels were increased compared with control. Moreover, CH prevented the trabecular bone loss induced by OVX and improved the microarchitecture of lumbar vertebrae. CH administration dose-dependently reduced the serum procollagen type I N-terminal propeptide level, which was elevated by OVX. The present study suggests that CH isolated in this study is a promising alternative to current therapeutic agents for the management of osteoporosis.

Inhibitory effects of Angelicae Gigantis Radix on osteoclast formation

Angelicae Gigantis Radix (AGR) is one of the most widely used herbal medications. AGR is the dried root of Angelica gigas Nakai (Umbelliferae), which is known as Korean angelica. This study investigated the effects of AGR on osteoclast formation using primary bone marrow cells. TNF‐α treatment increased tartrate‐resistant acid phosphatase (Trap) positive cells and Trap activity in bone marrow cells. However, AGR significantly decreased both TNF‐α‐induced Trap positive cells and Trap activity. RT‐PCR analyses revealed that AGR decreased mRNA levels of Trap and matrix metalloproteinase‐9 in TNF‐α‐treated bone marrow cells. In addition, AGR decreased TNF‐α‐induced activation of NF‐κB. These results suggest that AGR has an inhibitory effect on the formation of osteoclasts and its effect is partially related to the NF‐κB pathway. Copyright

Effects of Egg Yolk Proteins on the Longitudinal Bone Growth of Adolescent Male Rats

Hen egg is a nutritional store for a new life. We examined the effect of egg yolk proteins on longitudinal bone growth in the rat. Protein fractions from egg yolk were tested. Milk protein, casein, was used as a control. The bone growth rate was significantly increased by yolk water-soluble protein (YSP, 100 mg/kg) administration for 5 d. The bone morphogenetic protein-2 immunostaining of growth plate was also increased. Considering the results, YSP can be used as a growth-promoting factor.

Protective effect of ginsenoside Re on acute gastric mucosal lesion induced by compound 48/80

The protective effect of ginsenoside Re, isolated from ginseng berry, against acute gastric mucosal lesions was examined in rats with a single intraperitoneal injection of compound 48/80 (C48/80). Ginsenoside Re (20 mg/kg or 100 mg/kg) was orally administered 0.5 h prior to C48/80 treatment. Ginsenoside Re dose-dependently prevented gastric mucosal lesion development 3 h after C48/80 treatment. Increases in the activities of myeloperoxidase (MPO; an index of neutrophil infiltration) and xanthine oxidase (XO) and the content of thiobarbituric acid reactive substances (TBARS; an index of lipid peroxidation) and decreases in the contents of hexosamine (a marker of gastric mucus) and adherent mucus, which occurred in gastric mucosal tissues after C48/80 treatment, were significantly attenuated by ginsenoside Re. The elevation of Bax expression and the decrease in Bcl2 expression after C48/80 treatment were also attenuated by ginsenoside Re. Ginsenoside Re significantly attenuated all these changes 3 h after C48/80 treatment. These results indicate that orally administered ginsenoside Re protects against C48/80-induced acute gastric mucosal lesions in rats, possibly through its stimulatory action on gastric mucus synthesis and secretion, its inhibitory action on neutrophil infiltration, and enhanced lipid peroxidation in the gastric mucosal tissue.

Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway

Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na+-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway.

Inhibitory effects of ginsenoside re isolated from ginseng berry on histamine and cytokine release in human mast cells and human alveolar epithelial cells.

The berry of Panax ginseng significantly inhibited the histamine releases at the concentration of 30 μg/mL (p<0.05) and 10 μg/mL (p<0.01). The ginsenoside Re from ginseng berry was found out to have a potent effect in the experiment of histamin and cytokine release.

Inhibitory Effects of Egg Yolk Soluble Protein on Bone Resorption

We determined the effects of yolk water-soluble protein (YSP) on bone resorption. YSP potently suppressed osteoclastogenesis from bone marrow-derived precursor cells driven by tumor necrosis factor-α (TNF-α). YSP (200 μg/ml) abolished the formation of tartarate-resistant acid phosphatase (TRAP)-positive osteoclasts. Furthermore, TNF-α induced TRAP activity was greatly inhibited by YSP (100 μg/ml) treatment. Our results suggest that YSP has therapeutic potential for bone-erosive diseases.

Extrusion process of Acanthopanax senticosus leaves enhances the gastroprotective effect of compound 48/80 on acute gastric mucosal lesion in rats.

OBJECTIVE To investigate the gastroprotective effects of Acanthopanax senticosus leaves (ASLs) extrusion on acute gastric mucosal lesion in rats induced by compound 48/80 (C48/80). METHODS Rats were divided into six groups: normal; C48/80-induced gastric lesion control; gastric lesion positive control (famotidine 4 mg/kg); gastric lesion administered with two levels of extruded ASLs (ASLE, 40 and 200 mg/kg); and gastric lesion treated with ASLs (ASL 200 mg/kg). Mucus secretion/damage was determined by immunohistological staining. Immunofluorescence and western blotting were performed to determine gastric mucosal Bax and Bcl-2 expression. Gastric mucosal oxidative-stress-related enzymes and malondialdehvde were determined. RESULTS C48/80-induced mucus depletion and inflammation in the gastric mucosa were significantly attenuated by ASLs. The increased serum serotonin and histamine concentrations in C48/80-treated rats were also attenuated by ASLs. Gastric mucosal Bax protein expression was increased and Bcl-2 expression was decreased after C48/80 treatment, and ASLs ameliorated Bax and Bcl-2 expression. The extrusion process significantly augmented the effects of ASLs in a dose-dependent manner. ASLEs at 200 mg/kg normalized mucus damage/secretion, C48/80-induced increases of mucosal myeloperoxidase activity (index of inflammation), xanthine oxidase, and malondialdehyde content (index of lipid peroxidation). The effects of ASLs on Bax and Bcl-2 expression were also enhanced by extrusion. Furthermore, these effects of ASLEs at 200 mg/kg were similar to those of famotidine, a histamine H2-receptor antagonist commonly used to treat gastric ulcers. CONCLUSION ASLEs prevented acute gastric mucosal lesion progression induced by C48/80, possibly by inducing mucus production, and reduced inflammation and oxidative stress in gastric mucosa through an anti-apoptotic mechanism.

Comparison of the Effect of Velvet Antler from Different Sections on Longitudinal Bone Growth of Adolescent Rats

The aim of this study was to compare the effectiveness of velvet antler (VA) from different sections for promoting longitudinal bone growth in growing rats. VA was divided into upper (VAU), middle (VAM), and basal sections (VAB). An in vivo study was performed to examine the effect on longitudinal bone growth in adolescent rats. In addition, in vitro osteogenic activities were examined using osteoblastic MG-63 cells. VA promoted longitudinal bone growth and height of the growth plate in adolescent rats. Bone morphogenetic protein-2 (BMP-2) in growth plate of VA group was highly expressed compared with control. The anabolic effect of VA on bone was further supported by in vitro study. VA enhanced the proliferation, differentiation, and mineralization of MG-63 cells. The mRNA expressions of osteogenic genes such as collagen, alkaline phosphatase, and osteocalcin were increased by VA treatment. These effects of in vivo and in vitro study were decreased from upper to basal sections of VA. In conclusion, VA treatment promotes longitudinal bone growth in growing rats through enhanced BMP-2 expression, osteogenic activities, and bone matrix gene expressions. In addition, present study provides evidence for the regional differences in the effectiveness of velvet antler for longitudinal bone growth.

Involvement of MAPK signaling pathway in the osteogenic gene expressions of Cervi Pantotrichum Cornu in MG-63 human osteoblast-like cells

AIMS The purposes of this study were to determine whether Cervi Pantotrichum Cornu (CPC) has osteogenic activities in human osteoblastic MG-63 cells and to investigate the underlying molecular mechanism. MAIN METHODS The effects of CPC on alkaline phosphatase activity, collagen synthesis, and calcium deposits were measured. The COL1A1, ALPL, BGLAP, and SPP1 expressions were measured by real-time PCR. Phosphorylated MAP kinases (ERK1/2, JNK1/2, p38, ELK1, and cJUN) were studied by western blot analysis. The involvement of MAPK pathway in osteogenic gene expressions was determined by using each selective MAPK inhibitor (PD98059, SP600125, and SB203580). KEY FINDINGS CPC increased alkaline phosphatase activity, collagen synthesis, and calcium deposits. CPC activated ERK1/2, JNK1/2, p38, and ELK1 phosphorylation except cJUN. CPC increased the COL1A1, ALPL, BGLAP, and SPP1 gene expressions. The elevated COL1A1 and BGLAP expressions were inhibited by PD98059, SP600125 or SB203580. The elevated ALPL expression was blocked by SB203580. The elevated SPP1 expression was inhibited by SP600125 or SB203580. CPC increased COL1A1 and BGLAP expressions via ERK1/2, JNK1/2, and p38 MAPKs pathways and SPP1 expression via JNK1/2 and p38 pathways. p38 pathway is needed for ALPL expression. SIGNIFICANCE These results imply that MAPK signaling pathway is an indispensable factor for bone matrix genes expression of CPC in MG-63 human osteoblast-like cells.