• Journal of Oral Medicine and Pain
• /
• 제33권2호
• /
• pp.105-110
• /
• 2008

Baicalin은 Scutellaria baicalensis에서 분리되는 flavonoid의 일종으로, 다양한 생물학적 활성을 나타내는 물질로 알려져 있다. Baicalin은 항균, 항염증, 진통작용을 나타내며, nuclear factor-kappaB의 활성을 억제한다고 보고되었다. 최근에 다양한 flavonoid 들이 골조직 대사에 관여함이 밝혀졌으며, 본 연구에서는 baicalin이 골조직의 주요세포인 조골세포의 생성 및 활성에 미치는 영향을 관찰하기 위하여, 세포증식율, 세포생존율, 염기성 인산분해효소 활성 및 osteoprotegerin 생성량의 변화를 관찰하였다. 그 결과 baicalin은 조골세포의 세포 증식과 생존율에는 영향을 미치지 못하였으나, 염기성 인산분해효소의 활성과 osteoprotegerin의 생성량을 증가시켰다. 따라서 baicalin은 골조직에서 조절물질로 역할을 할 것으로 예견된다.

• BMB Reports
• /
• 제31권4호
• /
• pp.333-338
• /
• 1998

The sphingomyelin cycle and ceramide generation have been recognized as potential growth suppression signals in mammalian cells. Ceramide has been shown to induce differentiation, cell growth arrest, senescence, and apoptosis. Although the intracelluar target for the action of ceramide remains unknown, recent studies have demonstrated the role of cytosolic ceramideactivated protein phosphatase(CAPP). In this study, the cytotoxic effect of C2-ceramide, a synthetic cellpermeable ceramide analog, on HEp-2 cells and the mechanism by which ceramide induces cell death were investigated. The addition of exogenous C2-ceramide resulted in a concentration dependent cell death. Okadaic acid, a potent inhibitor of CAPP, enhanced ceramide-mediated cell death, which suggests that CAPP is not involved in this process. To understand the mechanism of action of ceramide, we studied the relationship between ceramide and c-Myc and pRb which are defined components of cell growth regulation. Western blot analyses revealed that C2-ceramide (10${\mu}M$) induced c-Myc down-regulation, but there were no significant changes in pRb. However, treatment of okadaic acid (10 nM) enhanced c-Myc and pRb down-regulation. Reduction of the amount of c-Myc and pRb occurred during HEp-2 cell death. These results suggest that the cytotoxic effect of ceramide in HEp-2 cells may not be mediated through the action of CAPP and that the downstream target for ceramide is c-Myc and pRb.

• Molecules and Cells
• /
• 제40권4호
• /
• pp.280-290
• /
• 2017

Several lines of evidence suggest that endoplasmic reticulum (ER) stress plays a critical role in the pathogenesis of many neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Protein tyrosine phosphatase 1B (PTP1B) is known to regulate the ER stress signaling pathway, but its role in neuronal systems in terms of ER stress remains largely unknown. Here, we showed that rotenone-induced toxicity in human neuroblastoma cell lines and mouse primary cortical neurons was ameliorated by PTP1B inhibition. Moreover, the increase in the level of ER stress markers ($eIF2{\alpha}$ phosphorylation and PERK phosphorylation) induced by rotenone treatment was obviously suppressed by concomitant PTP1B inhibition. However, the rotenone-induced production of reactive oxygen species (ROS) was not affected by PTP1B inhibition, suggesting that the neuroprotective effect of the PTP1B inhibitor is not associated with ROS production. Moreover, we found that MG132-induced toxicity involving proteasome inhibition was also ameliorated by PTP1B inhibition in a human neuroblastoma cell line and mouse primary cortical neurons. Consistently, downregulation of the PTP1B homologue gene in Drosophila mitigated rotenone- and MG132-induced toxicity. Taken together, these findings indicate that PTP1B inhibition may represent a novel therapeutic approach for ER stress-mediated neurodegenerative diseases.

• The Korean Journal of Physiology and Pharmacology
• /
• 제2권6호
• /
• pp.743-752
• /
• 1998

The atrial acetylcholine-activated $K^+\;(K_{ACh})$ channel is gated by the pertussis toxin-sensitive inhibitory G $(G_K)$ protein. Earlier studies revealed that ATP alone can activate the $K_{ACh}$ channel via transphosphorylation mediated by nucleoside-diphosphate kinase (NDPK) in atrial cells of rabbit and guinea pig. This channel can be activated by various agonists and also modulated its function by phosphorylation. ATP-induced $K_{ACh}$ channel activation (AIKA) was maintained in the presence of the NDPK inhibitor, suggesting the existence of a mechanism other than NDPK-mediated process. Here we hypothesized the phosphorylation process as another mechanism underlying AIKA and was undertaken to examine what kinase is involved in atrial cells isolated from the rat heart. Single application of 1 mM ATP gradually increased the activity of $K_{ACh}$ channels and reached its maximum $40{\sim}50$ sec later following adding ATP. AIKA was not completely reduced but maintained by half even in the presence of NDPK inhibitor. Neither ADP nor a non-hydrolyzable ATP analogue, AMP-PNP can cause AIKA, while a non-specific phosphatase, alkaline phosphatase blocked completely AIKA. PKC antagonists such as sphingosine or tamoxifen, completely blocked AIKA, whereas PKC catalytic domain increased AIKA. Taken together, it is suggested that the PKC-mediated phosphorylation is partly involved in AIKA.

• Natural Product Sciences
• /
• 제9권2호
• /
• pp.83-86
• /
• 2003

In the present study, Thespesia populnea (Malvaceae) bark was extracted with methanol and water. The extracts were vacuum dried to yield the respective methanol (MET) and aqueous extract (AET). The extracts were evaluated for hepatoprotective activity against carbon tetrachloride $(CCl_{4})$ induced liver damage at 2 dose levels (250 and 500 mg/kg). The biochemical parameters observed in serum were total bilirubin, alkaline phosphatase (ALP), serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) levels and total protein. Aspartate transaminase (AST), alanine transaminase (ALT) and total protein levels in liver were also evaluated. Histopathological study on the liver tissue was also performed. The extracts exhibited dose dependent reduction in total bilirubin, ALP SGOT, SGPT, AST, ALT and increase in total protein (serum and liver) levels. The extracts also exhibited only mild hepatocytic damage compared to the $CCl_{4}$ Treated group. MET was found to exhibit higher hepatoprotection than AET.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제47권6호
• /
• pp.454-464
• /
• 2021

Objectives: This study aimed to investigate the in vitro osteoinductivity of the combination of bone morphogenetic protein-2 (BMP-2) and nanohydroxyapatite (nHAp) and the in vivo effects of implants coated with nHAp/BMP-2. Materials and Methods: To evaluate the in vitro efficacy of nHAp/BMP-2 on bone formation, bone marrow-derived mesenchymal stem cells (BM-MSCs) were seeded onto titanium disks coated with collagen (Col), Col/nHAp, or Col/nHAp/BMP-2. Protein levels were determined by a biochemical assay and reverse transcriptase-polymerase chain reaction. Stem cell differentiation was analyzed by flow cytometry. For in vivo studies with mice, Col, Col/nHAp, and Col/nHAp/BMP-2 were injected in subcutaneous pockets. Titanium implants or implants coated with Col/nHAp/BMP-2 were placed bilaterally on rabbit tibias and evaluated for 4 weeks. Results: In the in vitro study, BM-MSCs on Col/nHAp/BMP-2 showed reduced levels of CD73, CD90, and CD105 and increased levels of glycosaminoglycan, osteopontin, and alkaline phosphatase activity. After 4 weeks, the Col/nHAp/BMP-2 implant showed greater bone formation than the control (P=0.07), while no differences were observed in bone implant contact and removal torque. Conclusion: These results suggest that a combination of BMP-2 and an nHAp carrier would activate osseointegration on dental implant surfaces.

• 대한의생명과학회지
• /
• 제27권4호
• /
• pp.223-230
• /
• 2021

Tumor necrosis factor alpha (TNF-α) is a principal regulator of inflammation and immunity. The proinflammatory properties of TNF-α can be attributed to its ability to activate the enzyme cytosolic phospholipase A₂ (cPLA₂), which generates potent inflammatory lipid mediators, eicosanoids. L-glutamine (Gln) plays physiologically important roles in various metabolic processes. We have reported that Gln has a potent anti-inflammatory activity via rapid upregulation of mitogen-activated protein kinases (MAPKs) phosphatase (MKP)-1, which preferentially dephosphorylates the key proinflammatory enzymes, p38 MAPK and cytosolic phospholipase A₂ (cPLA₂). In this study, we have investigated whether Gln could inhibit TNF-α-induced cPLA₂ activation. Gln inhibited TNF-α-induced increases in cPLA₂ phosphorylation in the lungs and blood levels of the cPLA₂ metabolites, leukotrine B4 (LTB4) (lipoxygenase metabolite) and prostaglandin E2 (PGE2) (cyclooxygenase metabolite). TNF-α increased p38 and cPLA₂ phosphorylation and blood levels of LTB4 and PGE2, which were blocked by the p38 inhibitor SB202190. Gln inhibited TNF-α-induced p38 and cPLA₂ phosphorylation and production of the cPLA₂ metabolites. Such inhibitory activity of Gln was no longer observed in MKP-1 small interfering RNA-pretreated animals. Our data indicate that Gln inhibited TNF-α-induced cPLA₂ phosphorylation through MKP-1 induction/p38 inhibition, and suggest that the utility of Gln in inflammatory diseases in which TNF-α plays a major role in their pathogenesis.

• Journal of Microbiology and Biotechnology
• /
• 제27권4호
• /
• pp.791-807
• /
• 2017

The type II secretion system (T2SS), which transports selected periplasmic proteins across the outer membrane, has rarely been studied in nonpathogens or in organisms classified as Betaproteobacteria. Therefore, we studied Cupriavidus metallidurans (Cme), a facultative chemilithoautotroph. Gel analysis of extracellular proteins revealed no remarkable differences between the wild type and the T2SS mutants. However, enzyme assays revealed that native extracellular alkaline phosphatase is a T2SS substrate, because activity was 10-fold greater for the wild type than a T2SS mutant. In Cme engineered to produce three Ralstonia solanacearum (Rso) exoenzymes, at least 95% of their total activities were extracellular, but unexpectedly high percentages of these exoenzymes remained extracellular in T2SS mutants cultured in rich broth. These conditions appear to permit an alternative secretion process, because neither cell lysis nor periplasmic leakage was observed when Cme produced a Pectobacterium carotovorum exoenzyme, and wild-type Cme cultured in minimal medium secreted 98% of Rso polygalacturonase, but 92% of this exoenzyme remained intracellular in T2SS mutants. We concluded that Cme has a functional T2SS despite lacking any abundant native T2SS substrates. The efficient secretion of three foreign exoenzymes by Cme is remarkable, but so too is the indication of an alternative secretion process in rich culture conditions. When not transiting the T2SS, we suggest that Rso exoenzymes are probably selectively packaged into outer membrane vesicles. Phylogenetic analysis of T2SS proteins supports the existence of at least three T2SS subfamilies, and we propose that Cme, as a representative of the Betaproteobacteria, could become a new useful model system for studying T2SS substrate specificity.

• 환경생물
• /
• 제19권4호
• /
• pp.302-312
• /
• 2001

Immunoglobulin G was purified by 40% $(NH_4)_2SO_4$ precipitation, DEAE-Sephadex, Sephadex G-150 column chromatographies from rabbit antiserum against V. vulnificus ATCC 27562 O antigen and used for immunological test for V. vulnificus isolates. The profiles of cell lysate total protein and outer membrane protein from the isolates were analyzed by SDS-PAGE and densitometry. The overall profiles in all isolates were similar. Distict protein band was observed in comparison with V. parahaemolyticus. Western Blotting with rabbit Immunoglobulin G against cell lysates and OMP of V. vulnificus isolates showed a strong antigenic response to antigen 66, 60, 54, 48, 33 and 26 kDa which were common to all strains examined. The 26 kDa antigen showed V. vulnificus specific antigen in comparison with Vibrio parahaemolyticus. A sandwich enzyme-linked immunosorbent assay was developed by using rat anti-V. vulnificus ATCC 27562 polyclonal antibodies as capture antibody, a purified rabbit IgG antibody as detector antibody, and goat anti-rabbit IgG-alkaline phosphatase conjugate as developer antibody. When four V. vulnificus isolates were tested, the reactivity showed from 50 to 70% by sandwich ELISA.

• Journal of Periodontal and Implant Science
• /
• 제34권4호
• /
• pp.747-757
• /
• 2004

The effect of chitosan, a carbohydrate biopolymer extracted from chitin, on periodontal regeneration is of particular interest. The purpose of this study was to evaluate the effect of chitosan on primary rat calvarial cells in vitro, with special focus on their proliferative properties by cell activity and the amount of total protein synthesis. The experimental groups were cultured with chitosan in concentration of 0.01, 0.1, 1.0, 2.0 and 5.0 mg/ml for MTT assay. In the experimental groups, cells were cultured with chitosan in concentration of 0.01, 0.1, 1.0 and 2.0 mg/ml. Each group was characterized by examining alkaline phosphatase activity at 3 and 7 days and the ability to produce mineralized nodules of rat calvarial cells at 14 and 21 days. The results were as follows: 1. The cell activity was not reduced in the concentration of $0.01{\sim}1.0$ mg/ml whereas the cell activity was reduced in the concentration of 5.0 mg/ml than the control at day 1 and 3 (p<0.05). 2. Primary rat calvarial cells treated with chitosan in the concentration 0.01 mg/ml and 0.1 mg/ml showed more protein synthesis than the control at day 3 (p<0.01), But primary rat calvarial cells treated with chitosan showed more protein synthesis than in control but they didn't have statistically difference among groups at day 7. 3. At 3 and 7 days, alkaline phosphatase activity was significantly increased in the concentration of 0.01 mg/ml. 0.1 mg/ml and 1.0 mg/ml (p<0.05). 4. The percentage of mineralized bone nodule was more in the concentration of chitosan 0.1 mg/ml and 1.0 mg/ml than the control. These results suggested that chitosan has a positive effect on the bone formation of primary rat calvarial cells in the concentration of 0.1 mg/ml and 1.0 mg/ml.