• Title/Summary/Keyword: Phosphatase inhibition

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Morphine induced inhibition of the activities of accessory reproductive ducts in male rats

  • Londonkar, Ramesh L.;Sharangouda, Sharangouda;Patil, Saraswati B.
    • Advances in Traditional Medicine
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    • v.8 no.1
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    • pp.67-72
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    • 2008
  • Adult male albino rats were treated with 0.5 mg and 0.75 mg morphine/100 g body weight intraperitoneally for 30 days. All the animals were autopsied on $31^{st}$ day. Epididymis and vas deferens were dissected out, weighed and processed for histological and biochemical studies. Morphine has caused a reduction in the weight of epididymis and vas deferens in both the doses of drug treated groups. The total cholesterol content is increased while protein, DNA and RNA contents and epididymal sperm counts are decreased. The acid phosphatase content is decreased 10.12 $\pm$ 0.11 in caput, 9.26 $\pm$ 0.30 in cauda of epididymis and in vas deferens 8.14 $\pm$ 0.15 in 0.5 mg treated groups and in 0.75 mg treated rats shows 9.52 $\pm$ 0.27 in caput, 9.14 $\pm$ 0.18 in cauda of epididymis and in vas deferens 7.84 $\pm$ 0.11is decreased, whereas alkaline phosphatase is increased. The surface epithelial cell height of these ducts is reduced and secretory activity is inhibited with the disruption of epithelial cell projections. The gravimetric and histometric changes of epididymis and vas deferens may be due to non-availability of androgens in morphine treated rats.

Effects of Asparagus cochinchinensis (Lour.) Merr. on the Stimulation of Osteoblast Differentiation and Inhibition of Osteoclast Generation (천문동 추출물에 의한 조골세포 분화 촉진 및 파골세포 생성 억제효과)

  • Lee, Seung-Youn;Kim, Si-Na;Kim, Jong-Keun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.37 no.1
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    • pp.16-19
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    • 2008
  • Bone mass in adults decreases with age because of the imbalance between the rate of bone formation and resorption. We performed this study to investigate whether Asparagus cochinchinensis (Lour.) Merr. (ACAE) plays a role in osteoblasts differentiation and osteoclasts formation. Ethanol extract of ACAE showed increase in the differentiation and alkaline phosphatase activity of osteoblasts. Also, it decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (OCLs) and TRAP activity. Therefore, ACAE has the potential to prevent bone-related diseases such as osteoporosis by increasing the differentiation of osteoblasts and reducing both the number and activity of osteoclasts.

STAT3 and SHP-1: Toward Effective Management of Gastric Cancer

  • Moon Kyung Joo
    • Journal of Digestive Cancer Research
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    • v.6 no.1
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    • pp.6-10
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    • 2018
  • The importance of signal transducer and activator of transcription 3 (STAT3) signaling in gastric carcinogenesis was firmly evaluated in the previous studies. Fully activated STAT3 induces various target genes involving tumor invasion and epithelial-mesenchymal transition (EMT), and mediates interaction between cancer cells and microenvironmental immune cells. Thus, suppression of STAT3 activity is an important issue for inhibition of gastric carcinogenesis and invasion. Unfortunately, data from clinical studies of direct inhibitor targeting STAT3 have been disappointing. SH2-containing protein tyrosine phosphatase 1 (SHP-1) effectively dephosphorylates and inhibits STAT3 activity, which has not been extensively studied gastric cancer research field. However, by summarizing recent data, it is evident that protein and gene expression of SHP-1 are minimal in gastric cancer cells, and induction of SHP-1 effectively downregulates phosphorylated STAT3 and inhibits cellular invasion in gastric cancer cells. Several SHP-1 inducers have been investigated in the experimental studies, including proton pump inhibitor, arsenic trioxide, and other natural compounds. Taken together, we suggest that modulation of SHP-1/STAT3 signaling axis may present a new way for treatment of gastric cancer, and development of effective SHP-1 inducer may be an important task in the future search field of gastric cancer.

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Effects of Chitosan on Human Gingival Fibroblasts in Vitro (키토산이 치은섬유아세포에 미치는 영향)

  • Kim, Ok-Su;Chung, Hyun-Ju
    • Journal of Periodontal and Implant Science
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    • v.32 no.1
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    • pp.235-247
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    • 2002
  • The aim of this study was to evaluate the effects of chitosan coating on the attachment, proliferation, functional and morphological change of human gingival fibroblasts. Primary culture of human gingival fibroblasts were grown in Dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. In experimental group, cells were inoculated in the multiwell plates coated with chitosan in concentration of 0.02, 0.2, and 2 mg/ml. Cell counting and MTT assay were done after 0.5, 1.5, 3, 6 and 24 hours of incubation to evaluate the cell attachment, and then after 2 and 7 days of culture to evaluate the cell proliferation. The alkaline phosphatase activity was measured after 4 and 7 days of culture and the ability to produce mineralized nodules was evaluated after 21 days of culture. The results were as follows : The morphology of cells on the chitosan-coated well was round or spheric. Round cells were aggregated since 6 hours of culture and showed nodule-like appearance after 24 hours of culture and did not achieved confluency at 7 days. The attachment of gingival fibroblasts was inhibited by chitosan coating with a tendency of dose dependent pattern. But, cellular activity of unit cell was higher than control. The proliferation of gingival fibroblasts was inhibited by chitosan coating at 2 mg/ml(P<0.01), while the cell proliferation at 0.02, 0.2 $mg/m{\ell}$ was comparable to the control well. Total alkaline phosphatase activity was inhibited by chitosan coating and decreased in the course of time. While ALP activity of unit cell was the highest at 2mg/ml after 4 days of culture. Finally, gingival fibroblasts produced the mineralized nodule at 2 mg/ml. In summary, the attachment, proliferation, and alkaline phosphatase activity of gingival fibroblasts were influenced differently by the concentration of coated chitosan. From this study, it could be used as the matrix of tissue engineering for gingiva without inhibition on proliferation of gingival fibroblasts using chitosan at the optimal concentration (0.02mg/ml).

Effect of Ssangwha-tang Fermented by Lactobacillus fermentum on Osteoclast Differentiation and Osteoporosis of Ovariectomized Rats (Lactobacillus fermentum으로 발효한 쌍화탕의 파골 세포 분화와 난소 적출한 랫트의 골다공증에 미치는 영향)

  • Shim, Ki-Shuk;Lee, Ji-Hye;Lee, Jae-Hoon;Ma, Jin-Yeul
    • Korean Journal of Oriental Medicine
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    • v.16 no.1
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    • pp.149-155
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    • 2010
  • Objective : Ssangwha-tang is a traditional medicine formula widely prescribed for a decrease of fatigue after an illness in Korea. The aim of this study is to investigate the effect of Ssangwha-tang fermented by Lactobacillus fermentum (SF) on osteoclast differentiation in vitro and on bone metabolism of an ovariectomized rat in vivo. Methods : Tartrate-resistant acid phosphatase activity and staining were applied to evaluate the formation of osteoclasts. Ovariectomized rats were orally administrated with SF (30 ml/kg/day) for 12 weeks. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, triglyceride, phosphate, calcium levels were determined. Effect of SF on bone loss were studied by histological analysis and the measurement of bone mineral density. Results : SF significantly inhibited tartrate-resistant acid phosphatase activity and formation of osteoclasts in RAW264.7 cells stimulated by receptor activator for nuclear factor ${\kappa}B$ (NF-${\kappa}B$) ligand (RANKL). In addition, SF significantly decreased the level of triglyceride and increased the level of low-density lipoprotein. Moreover, the decrease of trabeculae of the femur was partially prevented in ovariectomized rats administrated with SF. Conclusions : SF treatment could prevent ovariectomy induced bone loss and its effects could be medicated by the inhibition of osteoclastogenesis.

Conversion of Gycosylphosphatidylinositol (GPI)-Anchored Alkaline Phosphatase by GPI-PLD

  • Moon, Young-Girl;Lee, Hyun-Jung;Kim, Mee-Ree;Myung, Pyung-Keun;Park, Soo-Young;Sok, Dai-Eun
    • Archives of Pharmacal Research
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    • v.22 no.3
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    • pp.249-254
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    • 1999
  • Enzymatic conversion of brain glycosylphosphatidylinositol-linked alkaline phosphatase (GPI-AP), amphiphilic, was examined. When GPI-AP was incubated with glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD), a negligible conversion of GPI-AP to hydrophilic form was observed. The inclusion of monoacylglycerols enhanced the enzymatic conversion, although the action of monoacylglycerols differed greatly according to the size of acyl group; the enzymatic conversion was enhanced considerably in the presence of monoacylglycerols possessing acyl group of longer chain length ($C_{10-}C_{18}$), which monoacylglycerols with acyl moiety of shorter length ($C_{4-}C_{8}$) did fail to augment the enzymatic conversion. Noteworthy, monooleoylglycerol was much more effective than the other monoacylglycerols in promoting the enzymatic conversion, indicating a beneficial role of the unsaturation in acyl chain. Meanwhile, ionic amphiphiles such as monohexadecyllysophosphatidylcholoine and palmitoyl-carnitine decreased the enzymatic conversion of GPI-AP in a concentration-dependent manner, with monohexadecyllysophosphatidylcholine and palmitoyl-carnitine deceased the enzymatic conversion of GPI-AP in a concentration-dependent manner, with monohexadecyllysophosphatidylcholoine being more inhibitory than palmitoylcarnitine. Separately when GPI-AP was exposed to various oxidants prior to the incubation with GPI-PLD, a remarkable decrease of the enzymatic conversion was observed with hypochlorite and peroynitrite generators, but not $H_{2}O_{2}$. In further study, hypochlorite was found to inactivate GPI-PLD at low concentrations ($3~100{\mu}M$). From these results, it is suggested that the enzymatic conversion of GPI-AP by GPI-PLD may be regulated in vivo system.

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Competitive Enzyme-Linked Immunosorbent Assay for Glucose-6-Phosphate Dehydrogenase

  • Kim, Moon-Hee
    • BMB Reports
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    • v.30 no.5
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    • pp.326-331
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    • 1997
  • To construct a competitive ELISA standard curve for the detection of glucose-6-phosphate debydrogenase (G6PD), we used highly purified native G6PD (nG6PD) as both immobilized and soluble antigens and anti-G6PD serum raised against nG6PD as antibody. The polystyrene cuvettes coated with nG6PD were challenged with a mixture of a limiting amount of anti-G6PD serum and various doses of nG6PD as competitors followed by incubation with alkaline phosphatase-anti-IgG conjugate. The competitive ELISA did not exhibit the typical sigmoidal dose-response curve characteristic of competition immunoassays under the optimal concentrations of antigen and antibody. The soluble nG6PD used as competitor failed to effectively inhibit the binding of antibodies to the immobilized nG6PD. The addition of NADP, a cofactor of G6PD enzyme, to coating buffer used for immobilizing nG6PD to the cuvettes and PBS-Tween-BSA buffer for diluting competitors did not improve the inhibition of antibody binding to immobilized nG6PD by soluble n/G6PD. The addition of BSA to coating buffer did not increase inhibition, either. Surprisingly, when partially active G6PD (paG6PD), obtained by repeated freeze-thawing, was used as competitor, the antibody binding to either immobilized nG6PD or immobilized paG6PD was inhibited 49-58%. We conclude that an effective competitive ELISA system with nG6PD enzyme and anti-G6PD serum for the detection of G6PD may not be established due to the poor inhibition of antibody binding to immobilized nG6PD by soluble nG6PD under the present assay conditions and that the inhibition may be improved by using an inactivated enzyme as competitor regardless of the type of immobilized antigen used. These results imply that the immobilized nG6PD may undergo denaturation upon binding to the polystyrene cuvettes and that our anti-G6PD serum may recognize denatured enzyme better than active enzyme.

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Regulation of BAD Protein by PKA, PKCδ and Phosphatases in Adult Rat Cardiac Myocytes Subjected to Oxidative Stress

  • Cieslak, Danuta;Lazou, Antigone
    • Molecules and Cells
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    • v.24 no.2
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    • pp.224-231
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    • 2007
  • $H_2O_2$, as an example of oxidative stress, induces cardiac myocyte apoptosis. Bcl-2 family proteins are key regulators of the apoptotic response while their functions can be regulated by post-translational modifications including phosphorylation, dimerization or proteolytic cleavage. In this study, we examined the role of various protein kinases in regulating total BAD protein levels in adult rat cardiac myocytes undergoing apoptosis. Stimulation with 0.1 mM $H_2O_2$, which induces apoptosis, resulted in a marked down-regulation of BAD protein, which is attributed to cleavage by caspases since it can be restored in the presence of a general caspase inhibitor. Inhibition of PKC, p38-MAPK, ERK1/2 and PI-3-K did not influence the reduced BAD protein levels observed after stimulation with $H_2O_2$. On the contrary, inhibition of PKA or specifically $PKC{\delta}$ resulted in up-regulation of BAD. Decreased caspase 3 activity was observed in $H_2O_2$ treated cells after inhibition of PKA or $PKC{\delta}$ whereas inhibition of PKA also resulted in improved cell survival. Furthermore, addition of okadaic acid to inhibit selected phosphatases resulted in enhanced BAD cleavage. These data suggest that, during oxidative stress-induced cardiac myocyte apoptosis, there is a caspase-dependent down-regulation of BAD protein, which seems to be regulated by coordinated action of PKA, $PKC{\delta}$ and phosphatases.

Type 3 muscarinic acetylcholine receptor stimulation is a determinant of endothelial barrier function and adherens junctions integrity: role of protein-tyrosine phosphatase 1B

  • Jiao, Zhou-Yang;Wu, Jing;Liu, Chao;Wen, Bing;Zhao, Wen-Zeng;Du, Xin-Ling
    • BMB Reports
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    • v.47 no.10
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    • pp.552-557
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    • 2014
  • The main purpose of this study was to investigate whether type 3 muscarinic acetylcholine receptor (M3R) dysfunction induced vascular hyperpermeability. Transwell system analysis showed that M3R inhibition by selective antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) and small interfering RNA both increased endothelial permeability. Using coimmunoprecipitation and Western blot assay, we found that M3R inhibition increased VE-cadherin and ${\beta}$-catenin tyrosine phosphorylation without affecting their expression. Using PTP1B siRNA, we found that PTP1B was required for maintaining VE-cadherin and ${\beta}$-catenin protein dephosphorylation. In addition, 4-DAMP suppressed PTP1B activity by reducing cyclic adenosine monophosphate (cAMP), but not protein kinase $C{\alpha}$ ($PKC{\alpha}$). These data indicate that M3R preserves the endothelial barrier function through a mechanism potentially maintaining PTP1B activity, keeping the adherens junction proteins (AJPs) dephosphorylation.

Inhibition of IκB Kinase β (IKKβ) and Anti-diabetic Effect of SA51

  • Bhattarai, Bharat Raj;Kafle, Bhooshan;Hwang, Ji-Sun;Han, Inn-Oc;Cho, Hyeongjin
    • Bulletin of the Korean Chemical Society
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    • v.34 no.8
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    • pp.2487-2490
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    • 2013
  • SA51, a medium potency inhibitor of protein tyrosine phosphatase 1B (PTP1B), was identified to be a potent inhibitor of $I{\kappa}B$ kinase ${\beta}$ ($IKK{\beta}$). Consistent with this, SA51 prevented lipopolysaccharide (LPS)-induced breakdown of $I{\kappa}B{\alpha}$ in macrophages. The effects of SA51 in mice were compared with those of structurally related compounds, SA18 and SA32, which were previously reported as inhibitors of both enzymes - less potent against $IKK{\beta}$ but more potent against PTP1B compared to SA51. SA51 improved glucose tolerance and lipid parameters in mice, consistent with the results reported for $IKK{\beta}^{+/-}$ mice. In contrast, SA18 and SA32 showed anti-obesity effects without anti-diabetic effects. Collectively, the effects of SA51 could be due largely to the inhibition of $IKK{\beta}$, whereas SA18 and SA32 may be more likely to inhibit PTP1B, consistent with their relative in vitro inhibitory effects.