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Sample records for interleukin-27 inhibits human

  1. Interleukin 27 inhibits atherosclerosis via immunoregulation of macrophages in mice.

    PubMed

    Hirase, Tetsuaki; Hara, Hiromitsu; Miyazaki, Yoshiyuki; Ide, Noriko; Nishimoto-Hazuku, Ai; Fujimoto, Hirokazu; Saris, Christiaan J M; Yoshida, Hiroki; Node, Koichi

    2013-08-01

    Chronic inflammation in arterial wall that is driven by immune cells and cytokines plays pivotal roles in the development of atherosclerosis. Interleukin 27 (IL-27) is a member of the IL-12 family of cytokines that consists of IL-27p28 and Epstein-Barr virus induced gene 3 (EBI3) and has anti-inflammatory properties that regulate T cell polarization and cytokine production. IL-27-deficient (Ldlr-/-Ebi3-/-) and IL-27 receptor-deficient (Ldlr-/-WSX-1-/-) Ldlr-/- mice were generated and fed with a high-cholesterol diet to induce atherosclerosis. Roles of bone marrow-derived cells in vivo and macrophages in vitro were studied using bone marrow reconstitution by transplantation and cultured peritoneal macrophages, respectively. We demonstrate that mice lacking IL-27 or IL-27 receptor are more susceptible to atherosclerosis compared with wild type due to enhanced accumulation and activation of macrophages in arterial walls. The number of circulating proinflammatory Ly6C(hi) monocytes showed no significant difference between wild-type mice and mice lacking IL-27 or IL-27 receptor. Administration of IL-27 suppressed the development of atherosclerosis in vivo and macrophage activation in vitro that was indicated by increased uptake of modified low-density lipoprotein and augmented production of proinflammatory cytokines. These findings define a novel inhibitory role for IL-27 in atherosclerosis that regulates macrophage activation in mice.

  2. Immunomodulatory activity of interleukin-27 in human chronic periapical diseases

    PubMed Central

    Li, Juan; Wang, Rong; Huang, Shi-Guang

    2017-01-01

    This study aims to observe expression of IL-27 on different cells in periapical tissues of different types of human chronic periapical diseases. Periapical tissue specimens of 60 donors, including healthy control (n=20), periapical granuloma group (n=20) and radicular cysts group (n=20), were fixed in 10% buffered formalin, stained with hematoxylin and eosin for histopathology. Then specimens were stained with double- immuno-fluorescence assay for identification of IL-27-tryptase (mast cells, MCs), IL-27-CD14 (mononuclear phagocyte cells, MPs) and IL-27-CD31 (endothelial cells, ECs) double-positive cells in periapical tissues. The results indicated that compared with healthy control, the densities (cells/mm2) of IL-27-tryptase, IL-27-CD14 and IL-27-CD31 double-positive cells were significantly increased in human chronic periapical diseases (periapical granuloma group and radicular cysts group) (P<0.001). The density of IL-27-tryptase double positive cells in radicular cysts group was significantly higher than those in periapical granuloma group (P<0.001). Densities of IL-27-CD14 and IL-27-CD31 double-positive cells in periapical granuloma group had no significant difference with those in radicular cysts group (P=0.170 and 0.138, respectively). IL-27-CD14 double positive cells density achieved to peak among three cell groups in radicular cysts groups. In conclusion, IL-27 expressed in MCs, MPs and ECs of human chronic periapical diseases with different degrees. IL-27-tryptase double-positive cells may participate in pathogenic mechanism of chronic periapical diseases, especially for formation of fibrous in periapical cysts. IL-27-CD14 and IL-27-CD31 double-positive cells may participate in immunologic response to resist periapical infection, and they may play an dual role in pathogenesis and localization of periapical diseases. PMID:28386371

  3. Immunomodulatory activity of interleukin-27 in human chronic periapical diseases.

    PubMed

    Li, Juan; Wang, Rong; Huang, Shi-Guang

    2017-01-01

    This study aims to observe expression of IL-27 on different cells in periapical tissues of different types of human chronic periapical diseases. Periapical tissue specimens of 60 donors, including healthy control (n=20), periapical granuloma group (n=20) and radicular cysts group (n=20), were fixed in 10% buffered formalin, stained with hematoxylin and eosin for histopathology. Then specimens were stained with double- immuno-fluorescence assay for identification of IL-27-tryptase (mast cells, MCs), IL-27-CD14 (mononuclear phagocyte cells, MPs) and IL-27-CD31 (endothelial cells, ECs) double-positive cells in periapical tissues. The results indicated that compared with healthy control, the densities (cells/mm(2)) of IL-27-tryptase, IL-27-CD14 and IL-27-CD31 double-positive cells were significantly increased in human chronic periapical diseases (periapical granuloma group and radicular cysts group) (P<0.001). The density of IL-27-tryptase double positive cells in radicular cysts group was significantly higher than those in periapical granuloma group (P<0.001). Densities of IL-27-CD14 and IL-27-CD31 double-positive cells in periapical granuloma group had no significant difference with those in radicular cysts group (P=0.170 and 0.138, respectively). IL-27-CD14 double positive cells density achieved to peak among three cell groups in radicular cysts groups. In conclusion, IL-27 expressed in MCs, MPs and ECs of human chronic periapical diseases with different degrees. IL-27-tryptase double-positive cells may participate in pathogenic mechanism of chronic periapical diseases, especially for formation of fibrous in periapical cysts. IL-27-CD14 and IL-27-CD31 double-positive cells may participate in immunologic response to resist periapical infection, and they may play an dual role in pathogenesis and localization of periapical diseases.

  4. Interleukin-27 inhibits ectopic lymphoid-like structure development in early inflammatory arthritis

    PubMed Central

    Bombardieri, Michele; Greenhill, Claire J.; McLeod, Louise; Nerviani, Alessandra; Rocher-Ros, Vidalba; Cardus, Anna; Williams, Anwen S.; Pitzalis, Costantino; Jenkins, Brendan J.

    2015-01-01

    Ectopic lymphoid-like structures (ELSs) reminiscent of secondary lymphoid organs often develop at sites of chronic inflammation where they contribute to immune-mediated pathology. Through evaluation of synovial tissues from rheumatoid arthritis (RA) patients, we now show that low interleukin-27 (IL-27) expression corresponds with an increased incidence of ELS and gene signatures associated with their development and activity. The presence of synovial ELS was also noted in mice deficient in the IL-27 receptor (IL-27R) after the onset of inflammatory arthritis. Here, pathology was associated with increased synovial expression of pro-inflammatory cytokines, homeostatic chemokines, and transcriptional regulators linked with lymphoid neogenesis. In both clinical and experimental RA, synovial ELS coincided with the heightened local expression of cytokines and transcription factors of the Th17 and T follicular helper (Tfh) cell lineages, and included podoplanin-expressing T cells within lymphoid aggregates. IL-27 inhibited the differentiation of podoplanin-expressing Th17 cells, and an increased number of these cells were observed in IL-27R–deficient mice with inflammatory arthritis. Thus, IL-27 appears to negatively regulate ELS development in RA through control of effector T cells. These studies open new opportunities for patient stratification and treatment. PMID:26417004

  5. Interleukin-27 inhibits ectopic lymphoid-like structure development in early inflammatory arthritis.

    PubMed

    Jones, Gareth W; Bombardieri, Michele; Greenhill, Claire J; McLeod, Louise; Nerviani, Alessandra; Rocher-Ros, Vidalba; Cardus, Anna; Williams, Anwen S; Pitzalis, Costantino; Jenkins, Brendan J; Jones, Simon A

    2015-10-19

    Ectopic lymphoid-like structures (ELSs) reminiscent of secondary lymphoid organs often develop at sites of chronic inflammation where they contribute to immune-mediated pathology. Through evaluation of synovial tissues from rheumatoid arthritis (RA) patients, we now show that low interleukin-27 (IL-27) expression corresponds with an increased incidence of ELS and gene signatures associated with their development and activity. The presence of synovial ELS was also noted in mice deficient in the IL-27 receptor (IL-27R) after the onset of inflammatory arthritis. Here, pathology was associated with increased synovial expression of pro-inflammatory cytokines, homeostatic chemokines, and transcriptional regulators linked with lymphoid neogenesis. In both clinical and experimental RA, synovial ELS coincided with the heightened local expression of cytokines and transcription factors of the Th17 and T follicular helper (Tfh) cell lineages, and included podoplanin-expressing T cells within lymphoid aggregates. IL-27 inhibited the differentiation of podoplanin-expressing Th17 cells, and an increased number of these cells were observed in IL-27R-deficient mice with inflammatory arthritis. Thus, IL-27 appears to negatively regulate ELS development in RA through control of effector T cells. These studies open new opportunities for patient stratification and treatment. © 2015 Jones et al.

  6. Elevated interleukin-27 levels in human neonatal macrophages regulate indoleamine dioxygenase in a STAT-1 and STAT-3-dependent manner.

    PubMed

    Jung, Joo-Yong; Gleave Parson, Madeline; Kraft, Jennifer D; Lyda, Logan; Kobe, Brianna; Davis, Celestia; Robinson, Jembber; Peña, Maria Marjorette O; Robinson, Cory M

    2016-09-01

    Microbial infections are a major cause of infant mortality as a result of limitations in immune defences. Interleukin-27 (IL-27) is a heterodimeric cytokine produced primarily by leucocytes and is immunosuppressive toward lymphocytes and leucocytes. Our laboratory demonstrated that human neonatal macrophages express IL-27 more abundantly than adult macrophages. Similarly in mice, IL-27 expression is elevated early in life and maintained through infancy. To determine IL-27-regulated mechanisms that may limit immunity, we evaluated the expression of a number of genes in response to this cytokine in primary human neonatal macrophages. Indoleamine 2,3-dioxygenase (IDO) gene expression was increased dose-responsively by IL-27. We have previously demonstrated inhibition of T-cell proliferation and cytokine production by neonatal macrophage-generated IL-27, and IDO is often implicated in this negative regulation. An increase in IDO protein was demonstrated by immunofluorescence microscopy and was consistent with increased enzyme activity following treatment with IL-27. Inclusion of a soluble receptor to neutralize endogenous IL-27, decreased IDO expression and activity compared with untreated macrophages. In response to IL-27, neonatal macrophages phosphorylate signal transdcuer and activator of transcription 1 (STAT-1) and STAT-3. Both transcription factors are recruited to the IDO regulatory region. STAT-3 dominates during steady-state regulation by lower levels of endogenous IL-27 production. A shift to enhanced STAT-1 recruitment occurs during increased levels of exogenously supplied IL-27. These data suggest an interesting interplay of STAT-1 and STAT-3 to regulate IDO activity and immunosuppression in response to different levels of IL-27 in the microenvironment of the immune response that may further our understanding of this interesting cytokine.

  7. Interleukin-27 Inhibits Herpes Simplex Virus Type 1 Infection by Activating STAT1 and 3, Interleukin-6, and Chemokines IP-10 and MIG.

    PubMed

    Heikkilä, Outi; Nygårdas, Michaela; Paavilainen, Henrik; Ryödi, Elina; Hukkanen, Veijo

    2016-11-01

    Interleukin-27 (IL-27) inhibits the replication of many viruses, but the mechanism differs according to virus and cell type. In this study, we observed that IL-27 expression was upregulated in herpes simplex virus type 1 (HSV-1)-infected SJL/J mice, which led us to further investigate the role of IL-27 in HSV-1 infection using epithelial, glioma, and immunological cells as cell models. We showed that in all studied cell lines, the IL-27 messenger RNA (mRNA) level was upregulated due to the HSV-1 infection. When the cells were primed with IL-27 before the virus infection, the virus release was prevented, indicating an antiviral role of IL-27 in HSV-1 infection. Furthermore, we observed that IL-27 secretion to the culture medium was reduced in infected epithelial and immunological cells, but not in glioma cells. Not surprisingly, HSV-1 induced type I, II, and III interferons regardless of cell line, but IL-27 itself caused varying interferon responses dependent on cell type. However, common to all cell types was the IL-27-stimulated secretion of IL-6 and chemokines IP-10 and MIG. In addition, IL-27 stimulation activated STAT1 and STAT3 in HeLa and T98G cells, suggesting that IL-27 engages the STAT1/3 pathway, which then leads to the upregulation of IL-6, IP-10, and MIG.

  8. Interleukin-27 Early Impacts Leishmania infantum Infection in Mice and Correlates with Active Visceral Disease in Humans

    PubMed Central

    Pérez-Cabezas, Begoña; Cecílio, Pedro; Robalo, Ana Luisa; Silvestre, Ricardo; Carrillo, Eugenia; Moreno, Javier; San Martín, Juan V.; Vasconcellos, Rita; Cordeiro-da-Silva, Anabela

    2016-01-01

    The complexity of Leishmania–host interactions, one of the main leishmaniasis issues, is yet to be fully understood. We detected elevated IL-27 plasma levels in European patients with active visceral disease caused by Leishmania infantum, which returned to basal levels after successful treatment, suggesting this cytokine as a probable infection mediator. We further addressed this hypothesis recurring to two classical susceptible visceral leishmaniasis mouse models. BALB/c, but not C57BL/6 mice, showed increased IL-27 systemic levels after infection, which was associated with an upregulation of IL-27p28 expression by dendritic cells and higher parasite burdens. Neutralization of IL-27 in acutely infected BALB/c led to decreased parasite burdens and a transient increase in IFN-γ+ splenic T cells, while administration of IL-27 to C57BL/6 promoted a local anti-inflammatory cytokine response at the site of infection and increased parasite loads. Overall, we show that, as in humans, BALB/c IL-27 systemic levels are infection dependently upregulated and may favor parasite installation by controlling inflammation. PMID:27867384

  9. Interleukin-27-Mediated Suppression of Human Th17 Cells Is Associated with Activation of STAT1 and Suppressor of Cytokine Signaling Protein 1

    PubMed Central

    Liu, Hong

    2011-01-01

    Accumulating evidence indicates that interleukin (IL)-27, a member of the IL-12 family of cytokines, antagonizes pathological Th17 effector cell responses. Relatively little is known about the cytokines that regulate human Th17 cells. In this study, we investigated the effect of IL-27 on the differentiation of human Th17 cells and on committed memory Th17 cells. We demonstrate that IL-27 suppresses the development of human Th17 cells by downregulating retinoid orphan nuclear receptor C expression and that this inhibition is associated with the induction of the intracellular signaling factors STAT1 and induction of the suppressor of cytokine signaling protein 1. The IL-27-mediated inhibition of IL-17 is independent of IL-10. We show that IL-27 inhibits differentiation of naïve T cells into IL-17+ T cells under different Th17 polarizing conditions. IL-27 suppresses other Th17 subset cytokines such as IL-22 and IL-21 but not tumor necrosis factor-α. Moreover, we also show that IL-27 inhibits IL-17 production by committed Th17 memory cells, which is independent of IL-10. These studies show that IL-27 negatively regulates both the developing and committed human Th17 responses and therefore may be a promising therapeutic approach in the treatment of Th17-mediated diseases. PMID:21235411

  10. Human Immunodeficiency Virus Type-1 Myeloid Derived Suppressor Cells Inhibit Cytomegalovirus Inflammation through Interleukin-27 and B7-H4

    PubMed Central

    Garg, Ankita; Trout, Rodney; Spector, Stephen A.

    2017-01-01

    HIV/CMV co-infected persons despite prolonged viral suppression often experience persistent immune activation, have an increased frequency of myeloid derived suppressor cells (MDSC) and are at increased risk for cardiovascular disease. We examined how HIV MDSC control CD4+ T cell IFNγ response to a CMVpp65 peptide pool (CMVpp65). We show that HIV/CMV co-infected persons with virologic suppression and recovered CD4+ T cells compared to HIV(−)/CMV(+) controls exhibit an increase in CD4+CX3CR1+IFNγ+ cells in response to CMVpp65; MDSC depletion further augmented CD4+CX3CR1+IFNγ+ cells and IFNγ production. IL-2 and IFNγ in response to CMVpp65 were enhanced with depletion of MDSC expanded in presence of HIV (HIV MDSC), but decreased with culture of HIV MDSC with autologous PBMCs. CMVpp65 specific CD4+CX3CR1+IFNγ+ cells were also decreased in presence of HIV MDSC. HIV MDSC overexpressed B7-H4 and silencing B7-H4 increased the production of IL-2 and IFNγ from autologous cells; a process mediated through increased phosphorylated (p)-Akt upon stimulation with CMVpp65. Additionally, IL-27 regulated the expression of B7-H4 on HIV MDSC, and controlled CMV-specific T cell activity by limiting CMVpp65-IFNγ production and expanding CD4+IL-10+ regulatory T cells. These findings provide new therapeutic targets to control the chronic immune activation and endothelial cell inflammation observed in HIV-infected persons. PMID:28338007

  11. Interleukin-27 signaling promotes immunity against endogenously arising murine tumors.

    PubMed

    Natividad, Karlo D T; Junankar, Simon R; Mohd Redzwan, Norhanani; Nair, Radhika; Wirasinha, Rushika C; King, Cecile; Brink, Robert; Swarbrick, Alexander; Batten, Marcel

    2013-01-01

    Interleukin-27 (IL-27) is a pleiotropic cytokine but its immunosuppressive effects predominate during many in vivo immunological challenges. Despite this, evidence from tumor cell line transfer models suggested that IL-27 could promote immune responses in the tumor context. However, the role of IL-27 in immunity against tumors that develop in situ and in tumor immunosurveillance remain undefined. In this study, we demonstrate that tumor development and growth are accelerated in IL-27 receptor α (Il27ra)-deficient mice. Enhanced tumor growth in both carcinogen-induced fibrosarcoma and oncogene-driven mammary carcinoma was associated with decreased interferon-γ production by CD4 and CD8 T cells and increased numbers of regulatory T-cells (Treg). This is the first study to show that IL-27 promotes protective immune responses against endogenous tumors, which is critical as the basis for future development of an IL-27 based therapeutic agent.

  12. Interleukin-27 Signaling Promotes Immunity against Endogenously Arising Murine Tumors

    PubMed Central

    Natividad, Karlo D. T.; Junankar, Simon R.; Mohd Redzwan, Norhanani; Nair, Radhika; Wirasinha, Rushika C.; King, Cecile; Brink, Robert; Swarbrick, Alexander; Batten, Marcel

    2013-01-01

    Interleukin-27 (IL-27) is a pleiotropic cytokine but its immunosuppressive effects predominate during many in vivo immunological challenges. Despite this, evidence from tumor cell line transfer models suggested that IL-27 could promote immune responses in the tumor context. However, the role of IL-27 in immunity against tumors that develop in situ and in tumor immunosurveillance remain undefined. In this study, we demonstrate that tumor development and growth are accelerated in IL-27 receptor α (Il27ra)-deficient mice. Enhanced tumor growth in both carcinogen-induced fibrosarcoma and oncogene-driven mammary carcinoma was associated with decreased interferon-γ production by CD4 and CD8 T cells and increased numbers of regulatory T-cells (Treg). This is the first study to show that IL-27 promotes protective immune responses against endogenous tumors, which is critical as the basis for future development of an IL-27 based therapeutic agent. PMID:23554861

  13. Interleukin-27 exhibited anti-inflammatory activity during Plasmodium berghei infection in mice.

    PubMed

    Fazalul Rahiman, S S; Basir, R; Talib, H; Tie, T H; Chuah, Y K; Jabbarzare, M; Chong, W C; Mohd Yusoff, M A; Nordin, N; Yam, M F; Abdullah, W O; Abdul Majid, R

    2013-12-01

    Interleukin-27 (IL-27) has a pleiotropic role either as a pro-inflammatory or anti-inflammatory cytokine in inflammatory related diseases. The role and involvement of IL-27 during malaria was investigated and the effects of modulating its release on the production of major inflammatory cytokines and the histopathological consequences in major affected organs during the infection were evaluated. Results showed that IL-27 concentration was significantly elevated throughout the infection but no positive correlation with the parasitaemia development observed. Augmentation of IL-27 significantly elevated the release of anti-inflammatory cytokine, IL-10 whereas antagonising and neutralising IL-27 produced the opposite. A significant elevation of pro-inflammatory cytokines (IFN-γ and IL-6) was also observed, both during augmentation and inhibition of IL-27. Thus, it is suggested that IL-27 exerts an anti-inflammatory activity in the Th1 type response by signalling the production of IL-10 during malaria. Histopathological examination showed sequestration of PRBC in the microvasculature of major organs in malarial mice. Other significant histopathological changes include hyperplasia and hypertrophy of the Kupffer cells in the liver, hyaline membrane formation in lung tissue, enlargement of the white and red pulp followed by the disappearance of germinal centre of the spleen, and tubular vacuolation of the kidney tissues. In conclusion, it is suggested that IL-27 may possibly acts as an anti-inflammatory cytokine during the infection. Modulation of its release produced a positive impact on inflammatory cytokine production during the infection, suggesting its potential in malaria immunotherapy, in which the host may benefit from its inhibition.

  14. The role of interleukin-27 in predicting spontaneous HBeAg seroconversion in chronic hepatitis B infection.

    PubMed

    Li, Jie; Mak, Lung-Yi; Wong, Danny Ka-Ho; Fung, James; Seto, Wai-Kay; Lai, Ching-Lung; Yuen, Man-Fung

    2017-09-01

    Hepatitis B e seroconversion, associated with preceding hepatic inflammation, marks the transition from immune active to residual phase in the natural disease history of chronic hepatitis B. Recently, interleukin-27 has been reported to be associated with hepatic inflammation in hepatitis B infection. We aimed to evaluate the role of interleukin-27 in predicting spontaneous e seroconversion in chronic hepatitis B. A total of 142 treatment-naive hepatitis B patients with positive e antigen were recruited. Interleukin-27, hepatitis B viral DNA levels and liver function parameters, were measured on presentation. Patients who had spontaneous e seroconversion within 3 years of follow-up were compared with those without e seroconversion within the same period of time. Factors predictive of spontaneous e seroconversion were identified. Of the 142 patients (M:F=80:62, median age: 31), 44 (31%) had spontaneous e seroconversion within 3 years of follow-up. Multivariate analyses revealed that younger age, lower viral DNA and lower interleukin-27 levels on presentation independently predicted spontaneous e seroconversion: the rate was significantly higher in patients aged <31 (OR: 11.022, 95% CI: 3.658-33.205; P<.001), viral DNA <5 log IU/mL (OR: 2.311, 95% CI: 1.049-5.091; P=.038) and interleukin-27 <67.3 pg/mL (OR: 3.276, 95% CI: 1.257-8.536; P=.015). Among patients with all these three favourable factors on presentation, 77% of them underwent spontaneous e seroconversion within 3 years. Low interleukin-27 levels were associated with early e seroconversion. The combination of baseline interleukin-27 <67.3 pg/mL and viral DNA <5 log IU/mL in young patients was useful for predicting early spontaneous e seroconversion in treatment-naïve chronic hepatitis B patients. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Blockade of interleukin-27 signaling reduces GVHD in mice by augmenting Treg reconstitution and stabilizing Foxp3 expression.

    PubMed

    Belle, Ludovic; Agle, Kimberle; Zhou, Vivian; Yin-Yuan, Cheng; Komorowski, Richard; Eastwood, Daniel; Logan, Brent; Sun, Jie; Ghilardi, Nico; Cua, Daniel; Williams, Calvin B; Gaignage, Melanie; Marillier, Reece; van Snick, Jacques; Drobyski, William R

    2016-10-20

    Reestablishment of competent regulatory pathways has emerged as a strategy to reduce the severity of graft-versus-host disease (GVHD), and recalibrate the effector and regulatory arms of the immune system. However, clinically feasible, cost-effective strategies that do not require extensive ex vivo cellular manipulation have remained elusive. In the current study, we demonstrate that inhibition of the interleukin-27p28 (IL-27p28) signaling pathway through antibody blockade or genetic ablation prevented lethal GVHD in multiple murine transplant models. Moreover, protection from GVHD was attributable to augmented global reconstitution of CD4(+) natural regulatory T cells (nTregs), CD4(+) induced Tregs (iTregs), and CD8(+) iTregs, and was more potent than temporally concordant blockade of IL-6 signaling. Inhibition of IL-27p28 also enhanced the suppressive capacity of adoptively transferred CD4(+) nTregs by increasing the stability of Foxp3 expression. Notably, blockade of IL-27p28 signaling reduced T-cell-derived-IL-10 production in conventional T cells; however, there was no corresponding effect in CD4(+) or CD8(+) Tregs, indicating that IL-27 inhibition had differential effects on IL-10 production and preserved a mechanistic pathway by which Tregs are known to suppress GVHD. Targeting of IL-27 therefore represents a novel strategy for the in vivo expansion of Tregs and subsequent prevention of GVHD without the requirement for ex vivo cellular manipulation, and provides additional support for the critical proinflammatory role that members of the IL-6 and IL-12 cytokine families play in GVHD biology. © 2016 by The American Society of Hematology.

  16. Diagnostic accuracy of interleukin 27 for tuberculous pleural effusion: two prospective studies and one meta-analysis.

    PubMed

    Wang, Wen; Zhou, Qiong; Zhai, Kan; Wang, Yao; Liu, Jing-Yuan; Wang, Xiao-Juan; Wang, Zhen; Zhang, Jian-Chu; Tong, Zhao-Hui; Shi, Huan-Zhong

    2017-08-26

    Accurate differentiating diagnosis is essential for choosing treatment for exudative pleural effusions. To establish the diagnostic accuracy of interleukin 27 for tuberculous pleural effusion (TPE). First, the concentrations of pleural interleukin 27, interferon-gamma and adenosine deaminase were compared between 51 patients with TPE and 103 with non-TPEs (Beijing cohort), and their diagnostic values were evaluated. These were further verified in another independent population (Wuhan cohort, n=120). In the second part of the study, we performed a meta-analysis. With a cut-off value of 591.4 ng/L in the Beijing cohort, the area under the curve, sensitivity, specificity, positive predictive value and negative predictive value of interleukin 27 to diagnose TPE were 0.983 (95% CI 0.947 to 0.997), 96.1% (86.5% to 99.5%), 99.0% (94.7% to 100%), 98.0 (89.4 to 99.9) and 98.1 (93.3 to 99.8), respectively. Excellent diagnostic accuracy of interleukin 27 was also found in the Wuhan cohort and was further confirmed in the meta-analysis. The diagnostic performance of interleukin 27 was comparable to that of interferon-gamma and was more accurate than that of adenosine deaminase. Since the post-test probability of a negative result was always <0.1%, a negative test was considered to exclude TPE in all tuberculosis prevalence settings. Interleukin 27 can be used to diagnose TPE in a high prevalence setting, and a negative result can also be reliably used to rule out TPE in all prevalence settings. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Performance of interleukin-27 as a sepsis diagnostic biomarker in critically ill adults.

    PubMed

    Wong, Hector R; Liu, Kathleen D; Kangelaris, Kirsten N; Lahni, Patrick; Calfee, Carolyn S

    2014-10-01

    We recently identified interleukin-27 (IL-27) as a sepsis diagnostic biomarker in children. Here we assess IL-27 as a sepsis diagnostic biomarker in critically ill adults with systemic inflammatory response syndrome and sepsis. IL-27 and procalcitonin (PCT) were measured from plasma samples in three groups: no sepsis (n = 78), pulmonary source of sepsis (n = 66), and non-pulmonary source of sepsis (n = 43). Receiver operating characteristic curves and classification and regression tree methodology were used to evaluate biomarker performance. IL-27 did not discriminate effectively between sepsis and sterile systemic inflammatory response syndrome in unselected patients. The highest area under the curve (AUC) was 0.70 (95% C.I. 0.60 - 0.80) for IL-27 in subjects with a non-pulmonary source of sepsis. A decision tree incorporating IL-27, PCT, and age had an AUC of 0.79 (0.71-0.87) in subjects with a non-pulmonary source of sepsis. Compared to children with sepsis, adults with sepsis express less IL-27. IL-27 performed overall poorly in this cohort as a sepsis diagnostic biomarker. Combining IL-27, PCT, and age reasonably estimated the risk of sepsis in subjects with a non-pulmonary source of sepsis. IL-27 may be a more reliable sepsis diagnostic biomarker in children than in adults. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Performance of Interleukin-27 as a Sepsis Diagnostic Biomarker in Critically Ill Adults

    PubMed Central

    Wong, Hector R.; Liu, Kathleen D.; Kangelaris, Kirsten N.; Lahni, Patrick; Calfee, Carolyn S.

    2014-01-01

    Purpose We recently identified interleukin-27 (IL-27) as a sepsis diagnostic biomarker in children. Here we assess IL-27 as a sepsis diagnostic biomarker in critically ill adults with systemic inflammatory response syndrome (SIRS) and sepsis. Methods IL-27 and procalcitonin (PCT) were measured from plasma samples in three groups: no sepsis (n = 78), pulmonary source of sepsis (n = 66), and non-pulmonary source of sepsis (n = 43). Receiver operating characteristic curves and classification and regression tree methodology were used to evaluate biomarker performance. Results IL-27 did not discriminate effectively between sepsis and sterile SIRS in unselected patients. The highest area under the curve (AUC) was 0.70 (95% C.I. 0.60 – 0.80) for IL-27 in subjects with a non-pulmonary source of sepsis. A decision tree incorporating IL-27, PCT, and age had an AUC of 0.79 (0.71 – 0.87) in subjects with a non-pulmonary source of sepsis. Compared to children with sepsis, adults with sepsis express less IL-27. Conclusions IL-27 performed overall poorly in this cohort as a sepsis diagnostic biomarker. Combining IL-27, PCT, and age reasonably estimated the risk of sepsis in subjects with a non-pulmonary source of sepsis. IL-27 may be a more reliable sepsis diagnostic biomarker in children than in adults. PMID:24848949

  19. [Value of interleukin-27 as a diagnostic biomarker of sepsis in critically ill adults].

    PubMed

    Fu, Junjing; Wang, Yongtao; Zeng, Ping; Niu, Shanshan

    2015-06-01

    To evaluate interleukin-27 (IL-27) as a sepsis diagnostic biomarker in critically ill adults with sepsis. A retrospetive study was conducted. A total of 176 systemic inflammatory response syndrome (SIRS) patients in Department of Critical Care Medicine of Xinxiang Medical College First Affiliated Hospital from March to November in 2014 were enrolled. The patients were divided into no sepsis group (n=66), pulmonary originated sepsis group (n=65), and non-pulmonary originated sepsis group (n=45). Plasma IL-27 and procalcitonin (PCT) were determined with enzyme linked immunosorbent assay (ELISA). Receiver operating characteristic curve (ROC) and classification and regression tree methodology was used to evaluate diagnostic biomarker performance. The proportion of patients in pulmonary original sepsis group whose body temperature in line with SIRS criteria was significantly higher than no sepsis group (66.2% vs. 44.5%, P<0.05), and they were easy to suffer from tumor (44.6% vs. 22.7%, P<0.05). The proportion of patients in non-pulmonary originated sepsis group whose white blood cell count in line with SIRS criteria was significantly higher than no sepsis group (68.9% vs. 42.7%, P<0.05). It indicated that patients in pulmonary originated sepsis group and non-pulmonary originated sepsis group were more in line with SIRS criteria compared with no sepsis group. It was shown by ROC curve that IL-27 and PCT was not effective in discriminating sepsis among unselected patients showing symptoms and signs of SIRS. The area under the curve (AUC) was 0.59 [95% confidence interval (95%CI)=0.49-0.65] and 0.61 (95%CI=0.55-0.71). According to the further analysis from different infection sources, the highest AUC was 0.71 (95%CI=0.59-0.79) for IL-27 in patients with a non-pulmonary originated sepsis. A decision tree incorporating IL-27, PCT, and age had an AUC of 0.78 (95%CI=0.71-0.87) in patients with a non-pulmonary originated sepsis, which was higher than IL-27 [0.71(95%CI=0

  20. Interleukin-27 priming of T cells controls IL-17 production in trans via induction of the ligand PD-L1.

    PubMed

    Hirahara, Kiyoshi; Ghoreschi, Kamran; Yang, Xiang-Ping; Takahashi, Hayato; Laurence, Arian; Vahedi, Golnaz; Sciumè, Giuseppe; Hall, Aisling O'Hara; Dupont, Christopher D; Francisco, Loise M; Chen, Qian; Tanaka, Masao; Kanno, Yuka; Sun, Hong-Wei; Sharpe, Arlene H; Hunter, Christopher A; O'Shea, John J

    2012-06-29

    Interleukin-27 (IL-27) is a key immunosuppressive cytokine that counters T helper 17 (Th17) cell-mediated pathology. To identify mechanisms by which IL-27 might exert its immunosuppressive effect, we analyzed genes in T cells rapidly induced by IL-27. We found that IL-27 priming of naive T cells upregulated expression of programmed death ligand 1 (PD-L1) in a signal transducer and activator of transcription 1 (STAT1)-dependent manner. When cocultured with naive CD4(+) T cells, IL-27-primed T cells inhibited the differentiation of Th17 cells in trans through a PD-1-PD-L1 interaction. In vivo, coadministration of naive TCR transgenic T cells (2D2 T cells) with IL-27-primed T cells expressing PD-L1 inhibited the development of Th17 cells and protected from severe autoimmune encephalomyelitis. Thus, these data identify a suppressive activity of IL-27, by which CD4(+) T cells can restrict differentiation of Th17 cells in trans.

  1. Interleukin-27 is differentially associated with HIV viral load and CD4+ T cell counts in therapy-naïve HIV-mono-infected and HIV/HCV-co-infected Chinese.

    PubMed

    He, Lai; Zhao, Jin; Wang, Maggie Haitian; Siu, Kenny K Y; Gan, Yong-Xia; Chen, Lin; Zee, Benny C Y; Yang, Li; Kung, Hsiang-Fu; Yang, Zheng-Rong; He, Ming-Liang

    2014-01-01

    Human Immunodeficiency Virus (HIV) infection and the resultant Acquired Immunodeficiency Syndrome (AIDS) epidemic are major global health challenges; hepatitis C virus (HCV) co-infection has made the HIV/AIDS epidemic even worse. Interleukin-27 (IL-27), a cytokine which inhibits HIV and HCV replication in vitro, associates with HIV infection and HIV/HCV co-infection in clinical settings. However, the impact of HIV and HCV viral loads on plasma IL-27 expression levels has not been well characterized. In this study, 155 antiretroviral therapy-naïve Chinese were recruited. Among them 80 were HIV- and HCV-negative healthy controls, 45 were HIV-mono-infected and 30 were HIV/HCV-co-infected. Plasma level HIV, HCV, IL-27 and CD4+ number were counted and their correlation, regression relationships were explored. We show that: plasma IL-27 level was significantly upregulated in HIV-mono-infected and HIV/HCV-co-infected Chinese; HIV viral load was negatively correlated with IL-27 titer in HIV-mono-infected subjects whereas the relationship was opposite in HIV/HCV-co-infected subjects; and the relationships between HIV viral loads, IL-27 titers and CD4+ T cell counts in the HIV mono-infection and HIV/HCV co-infection groups were dramatically different. Overall, our results suggest that IL-27 differs in treatment-naïve groups with HIV mono-infections and HIV/HCV co-infections, thereby providing critical information to be considered when caring and treating those with HIV mono-infection and HIV/HCV co-infection.

  2. Elevated interleukin-27 enhances the polarization of Th1/Tc1 cells and the production of proinflammatory cytokines in primary immune thrombocytopenia.

    PubMed

    Li, Hui Yuan; Zhang, Dong Lei; Ge, Jing; Zhou, Hu; Qi, Ai ping; Ma, Li; Xue, Feng; Zhou, Ze Ping; Yang, Ren Chi

    2012-03-01

    Primary immune thrombocytopenia (ITP) is an acquired, organ-specific, autoimmune disease with many immune dysfunctions. Interleukin-27 (IL-27) can regulate T cell differentiation. However, it is unclear whether IL-27 correlates with the dysfunctions of T cell differentiation in ITP patients. Thus, to determine the roles of IL-27 in ITP, we studied the expression of IL-27/IL-27 receptor in ITP patients. The results indicated that the levels of IL-27 in the plasma of untreated active ITP patients were higher than in normal controls. We next evaluated the contribution of IL-27 to T cell differentiation. Our results indicated that IL-27 increased T-bet expression, inhibited GATA-3 and ROR-γt expression, and promoted the secretion of tumor necrosis factor-α, interferon-γ, and granzyme B of peripheral blood mononuclear cells from ITP patients. Also, we confirmed that IL-27 induced the differentiation of T helper (Th)-1 and Tc1 cells. In conclusion, IL-27 might play an important role in the pathogenesis of ITP by inducing the polarization of Th1/Tc1 cells and the production of proinflammatory cytokines.

  3. Antitumor effects obtained by autologous Lewis lung cancer cell vaccine engineered to secrete mouse interleukin 27 by means of cationic liposome.

    PubMed

    Zhang, Junfeng; Tian, Hongwei; Li, Can; Cheng, Lin; Zhang, Shuang; Zhang, Xiaomei; Wang, Ruibo; Xu, Fen; Dai, Lei; Shi, Gang; Chen, Xiaolei; Li, Yiming; Du, Tao; Deng, Jie; Liu, Yu; Yang, Yang; Wei, Yuquan; Deng, Hongxin

    2013-10-01

    Interleukin-27 (IL-27), a novel IL-6/IL-12 family cytokine, plays an important role in the early regulation of Th1 responses. The cytokine IL-27 can exert a variety of immune-regulatory functions including cytotoxic T lymphocyte (CTL), CD4+, CD8+ T lymphocytes activation and interferon-γ (IFN-γ) production. In this study, we developed an effective and gene modified tumor cell vaccine. Lewis lung cancer cell LL/2 transfected with the DOTAP:cholesterol cationic liposome could express the mouse IL-27 (mIL-27) gene at a relative high level. The resultant transfectants were then irradiated with X-ray and used as a tumor cell vaccine. This tumor cell vaccine not only contained tumor associated antigen (TAA) of LL/2 cells but also secreted mIL-27 which could induce immune response in mice. The mice vaccinated with LL/2-mIL-27 performed strong tumor inhibiting effect accompanied with a high IFN-γ production. Both CD4+ and CD8+ T lymphocytes were significantly elevated in these mice vaccinated with LL/2-mIL-27 cell vaccine. Moreover, after depletion of CD4+, CD8+ T lymphocytes by injection of antibodies against CD4 and CD8, the vaccinated mice inoculated with autologous LL/2 cells were not protected from tumor challenge. In contrast, vaccinated mice inoculated with autologous LL/2 cells were treated with antibody against natural killer (NK)cells or normal rat IgG still possessed strong antitumor activity. Our data suggested that DOTAP:cholesterol cationic liposome was quite useful in generating an autologous tumor cell vaccine and mIL-27 could be therapeutically used to potentiate the host antitumor immunity.

  4. The presence of interleukin-27 during monocyte-derived dendritic cell differentiation promotes improved antigen processing and stimulation of T cells

    PubMed Central

    Jung, Joo-Yong; Roberts, Lawton L; Robinson, Cory M

    2015-01-01

    Dendritic cells (DCs) are potent antigen-presenting cells necessary to establish effective adaptive immune responses. The cytokine environment that exists at the time of DC differentiation may be an important but often ignored determinant in the phenotypic and functional properties of DCs. Interleukin-27 (IL-27) is a unique cytokine that has both inflammatory and immune suppressive activities. Although it can both promote and oppose activity of different T-cell subsets, mostly anti-inflammatory activity has been described toward macrophages and DCs. However, the specific effect of IL-27 during DC differentiation and how that may change the nature of the antigen-presenting cell has not been investigated. In this report, we show that IL-27 treatment during monocyte-derived DC differentiation enhanced the ability to process antigens and stimulate T-cell activity. DCs differentiated in the presence of IL-27 showed enhanced acidification of latex bead-containing phagosomes that was consistent with elevated expression of vacuolar-ATPases. This resulted in inhibition of intracellular growth of Staphylococcus aureus. In addition, the levels of MHC class II surface expression were higher in DCs differentiated in the presence of IL-27. Production of IL-12 was also significantly increased during S. aureus infection of IL-27-differentiated DCs. The net effect of these activities was enhanced CD4+ T-cell proliferation and T helper type 1 cytokine production. These findings are important to a wide number of immunological contexts and should be considered in the development of future vaccines. PMID:25346485

  5. The presence of interleukin-27 during monocyte-derived dendritic cell differentiation promotes improved antigen processing and stimulation of T cells.

    PubMed

    Jung, Joo-Yong; Roberts, Lawton L; Robinson, Cory M

    2015-04-01

    Dendritic cells (DCs) are potent antigen-presenting cells necessary to establish effective adaptive immune responses. The cytokine environment that exists at the time of DC differentiation may be an important but often ignored determinant in the phenotypic and functional properties of DCs. Interleukin-27 (IL-27) is a unique cytokine that has both inflammatory and immune suppressive activities. Although it can both promote and oppose activity of different T-cell subsets, mostly anti-inflammatory activity has been described toward macrophages and DCs. However, the specific effect of IL-27 during DC differentiation and how that may change the nature of the antigen-presenting cell has not been investigated. In this report, we show that IL-27 treatment during monocyte-derived DC differentiation enhanced the ability to process antigens and stimulate T-cell activity. DCs differentiated in the presence of IL-27 showed enhanced acidification of latex bead-containing phagosomes that was consistent with elevated expression of vacuolar-ATPases. This resulted in inhibition of intracellular growth of Staphylococcus aureus. In addition, the levels of MHC class II surface expression were higher in DCs differentiated in the presence of IL-27. Production of IL-12 was also significantly increased during S. aureus infection of IL-27-differentiated DCs. The net effect of these activities was enhanced CD4(+) T-cell proliferation and T helper type 1 cytokine production. These findings are important to a wide number of immunological contexts and should be considered in the development of future vaccines.

  6. Transcription factor Fli-1 positively regulates lipopolysaccharide-induced interleukin-27 production in macrophages.

    PubMed

    Gao, Peng; Yuan, Ming; Ma, Xianwei; Jiang, Wei; Zhu, Lingxi; Wen, Mingyue; Xu, Jing; Liu, Qiuyan; An, Huazhang

    2016-03-01

    IL-27 is an important regulator of TLR4-activated innate immune. The mechanism by which IL-27 production is regulated in TLR4-activated innate immune remains largely unclear. Here we show that expression of transcription factor Fli-1 at protein level is increased in macrophages following LPS stimulation. Fli-1 overexpression increases LPS-activated IL-27 production in macrophages. Consistently, Fli-1 knockdown inhibits LPS-induced IL-27 production in macrophages. Chromatin immunoprecipitation (ChIP) assay reveals that Fli-1 binds the promoter of IL-27 p28 subunit. Further experiments manifest that Fli-1 binds the region between -250 and -150 bp upstream of the transcriptional start site of p28 gene and increases p28 gene promoter-controlled transcription. These results demonstrate that Fli-1 positively regulates IL-27 production in TLR4-activated immune response by promoting transcription of IL-27 p28 gene.

  7. Molecular Pathways in the Induction of Interleukin-27-Driven Regulatory Type 1 Cells

    PubMed Central

    Pot, Caroline; Apetoh, Lionel; Awasthi, Amit

    2010-01-01

    Type 1 regulatory (Tr1) cells have emerged as key players in the prevention of autoimmunity. They produce high levels of the immunosuppressive cytokine interleukin (IL)-10 and confer protection against a wide panel of autoimmune diseases. However, the molecular pathways leading to their generation have long remained elusive. We have recently identified IL-27, a member of the IL-12 cytokine family, as a novel cytokine that induces Tr1 cells. Further analysis of IL-27-driven Tr1 cells have identified a critical role of the transcription factor avian musculoaponeurotic fibrosarcoma v-maf and of IL-21 in the generation of IL-27-induced Tr1 cells. Importantly, IL-27 also induces Tr1 cells in humans, suggesting that IL-27 administration may dampen tissue inflammation in humans as well. Here, we review the role of IL-27 in the generation of Tr1 cells and discuss its potential to alleviate autoimmune diseases. PMID:20540648

  8. Interleukin-27 induces the endothelial differentiation in Sca-1+ cardiac resident stem cells.

    PubMed

    Tanaka, Tomohiro; Obana, Masanori; Mohri, Tomomi; Ebara, Masaki; Otani, Yuta; Maeda, Makiko; Fujio, Yasushi

    2015-10-01

    Cytokines play important roles in cardiac repair and regeneration. Recently, we demonstrated that interleukin (IL)-6 family cytokines induce the endothelial differentiation of Sca-1+ cardiac resident stem cells through STAT3/Pim-1 signaling pathway. In contrast, the biological functions of IL-12 family cytokines in heart remain to be elucidated, though they show structural homology with IL-6. In the present study, we examined the effects of IL-12 family cytokines on the transdifferentiation of cardiac Sca-1+ cells into cardiac cells. RT-PCR analyses revealed that IL-27 receptor α (IL-27Rα), but not IL-12R or IL-23R, was expressed in cardiac Sca-1+ cells. The transcript expression of IL-27 was elevated in murine hearts in cardiac injury models. Intriguingly, IL-27 stimulation for 14 days induced the endothelial cell (EC) marker genes, such as CD-31 and VE-cadherin. Immunoblot analyses clarified that IL-27 treatment rapidly phosphorylated STAT3. IL-27 upregulated the expression of Pim-1, but the overexpression of dominant negative STAT3 abrogated the induction of Pim-1 by IL-27. Finally, adenoviral transfection of dominant negative Pim-1 inhibited IL-27-induced EC differentiation of cardiac Sca-1+ cells. These findings demonstrated that IL-27 promoted the commitment of cardiac stem cells into the EC lineage, possibly leading to neovascularization as a novel biological function. IL-27 could not only regulate the inflammation but also contribute to the maintenance of the tissue homeostasis through stem cell differentiation at inflammatory sites. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Interleukin-27 as a potential therapeutic target for rheumatoid arthritis: has the time come?

    PubMed

    Gong, Fang; Pan, Yu-Hong; Huang, Xuan; Chen, Jiang; Xiao, Jin-Hua; Zhu, Hua-Yan

    2013-10-01

    Interleukin (IL)-27 is a novel member of the IL-6/IL-12 family of cytokines with a broad range of pro- and anti-inflammatory properties. Recently, accumulating evidence has shown that IL-27 can play either a pathogenic or a protective role in animal models of inflammatory arthritis, depending upon the model and underlying pathogenic mechanisms. As to human system, elevated expression of IL-27 has clearly been detected in the synovial membranes and fluid from patients with rheumatoid arthritis (RA). Moreover, stimulation of IL-27 receptor with IL-27 of fibroblast-like synoviocytes from RA had a suppressive effect on the production of proinflammatory cytokines in vitro. All these findings suggest that IL-27 may have promise as a potential therapeutic target for RA. In this review, we will discuss the biological features of IL-27 and summarize recent advances on both pathogenic and protective roles of IL-27 in RA.

  10. Cigarette Smoke Induction of Interleukin-27/WSX-1 Regulates the Differentiation of Th1 and Th17 Cells in a Smoking Mouse Model of Emphysema

    PubMed Central

    Qiu, Shi-Lin; Duan, Min-Chao; Liang, Yi; Tang, Hai-Juan; Liu, Guang-Nan; Zhang, Liang-Ming; Yang, Chao-Mian

    2016-01-01

    IFN-γ-producing CD4+ T (Th1) cells and IL-17-producing CD4+ T (Th17) cells play a critical role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the immune regulation between Th1 and Th17 cells remains unclear. Previous studies have demonstrated that interleukin-27 (IL-27)/WSX-1 exerted pro- or anti-inflammatory effects in many acute inflammatory diseases by modulating T cell-mediated immune response, but little was known about its role in chronic inflammatory disease, especially in smoking-related lung diseases. Considering IL-27 is an important regulator in T lymphocytes immune responses and was found markedly increased in patients with COPD, we hypothesized that IL-27/WSX-1 may exert immuno-regulatory effects on the differentiation of Th1 and Th17 cells in smoking-related COPD. In this study, we aimed to evaluate the expression of IL-27 in patients with COPD and explore the role of IL-27/WSX-1 on Th1 and Th17 cells differentiation in a smoking mouse model of emphysema. We found that elevated expression of IL-27 was associated with increased proportion of Th1 cells and Th17 cells in patients with COPD and demonstrated parallel findings in cigarette smoke-exposed mice. In addition, cigarette smoke exposure upregulated the expression of IL-27R (WSX-1) by naive CD4+ T cells in mice. In vitro, IL-27 significantly augmented the secretion of IFN-γ by naive CD4+ T cells via a T-bet, p-STAT1, and p-STAT3-dependent manner, but inhibited the production of IL-17 by a ROR-γt and p-STAT1-dependent way. Furthermore, anti-IL27 treatment dramatically decreased the expression of IFN-γ-producing CD4+ T cells in cigarette smoke-exposed mice. These findings proposed that IL-27 has functions for promoting the expression of Th1 cells but inhibiting the expression of Th17 cells in vitro and IL-27 neutralization-attenuated Th1-mediated inflammation in vivo, suggesting targeting IL-27/WSX-1 may provide a new therapeutic approach for smoking-related COPD

  11. Latent inhibition in human adults without masking.

    PubMed

    Escobar, Martha; Arcediano, Francisco; Miller, Ralph R

    2003-09-01

    Latent inhibition refers to attenuated responding to Cue X observed when the X-outcome pairings are preceded by X-alone presentations. It has proven difficult to obtain in human adults unless the preexposure (X-alone) presentations are embedded within a masking (i.e., distracting) task. The authors hypothesized that the difficulty in obtaining latent inhibition with unmasked tasks is related to the usual training procedures, in which the preexposure and conditioning experiences are separated by a set of instructions. Experiment 1 reports latent inhibition without masking in a task in which preexposure and conditioning occur without interruption. Experiments 2 and 3 demonstrate that this attenuation in responding to target Cue X does not pass a summation test for conditioned inhibition and is context specific, thereby confirming that it is latent inhibition. Experiments 3 and 4 confirm that introducing instructions between preexposure and conditioning disrupts latent inhibition.

  12. Interleukin-27 polymorphisms are associated with premature coronary artery disease and metabolic parameters in the Mexican population: the genetics of atherosclerotic disease (GEA) Mexican study

    PubMed Central

    Posadas-Sánchez, Rosalinda; Pérez-Hernández, Nonanzit; Rodríguez-Pérez, José Manuel; Coral-Vázquez, Ramón M.; Roque-Ramírez, Bladimir; Llorente, Luis; Lima, Guadalupe; Flores-Dominguez, Carmina; Villarreal-Molina, Teresa; Posadas-Romero, Carlos; Vargas-Alarcón, Gilberto

    2017-01-01

    Several studies suggest an important role of Interleukin-27 in the development of atherosclerosis. The aim of this study was to establish whether the IL-27p28 gene polymorphisms are associated with premature coronary artery disease and/or other cardiovascular risk factors. Four IL-27p28 gene polymorphisms were selected and genotyped in 1162 premature coronary artery disease cases and 1107 controls. rs26528 T and rs40837 A alleles were significantly associated with a lower risk of premature coronary artery disease under different inheritance models (Pdominant = 0.046; Pover-dominant = 0.002; Pco-dominant1 = 0.007 for rs26528T; Pover-dominant = 0.008 and Pco-dominant1 = 0.031 for rs40837). The rs40837 A allele was also associated with a lower risk of insulin resistance, in cases (Pover-dominant = 0.037) and controls (Padditive = 0.008; Pdominant = 0.047; Precessive = 0.014; Pco-dominant2 = 0.006), while the rs26528 T allele was associated with a lower risk of insulin resistance only in the control group (Precessive = 0.016; Pco-dominant2 = 0.021). Interleukin-27 plasma levels were measured in 450 controls and 450 cases, and were significantly higher in cases compared to controls (P = 0.004). However, Interleukin-27 plasma levels were not associated with IL-27p28 polymorphisms. Luciferase assays showed that co-transfection of the rs40837 A allele and miR-379-5p significantly decreased luciferase gene expression. Our study shows for the first time, that IL-27p28 gene polymorphisms are associated with premature coronary artery disease and with some metabolic parameters. The rs40837 A allele in presence of miR-379-5p significantly decreased luciferase gene expression. PMID:28969085

  13. Inhibition in the Human Auditory Cortex

    PubMed Central

    Inui, Koji; Nakagawa, Kei; Nishihara, Makoto; Motomura, Eishi; Kakigi, Ryusuke

    2016-01-01

    Despite their indispensable roles in sensory processing, little is known about inhibitory interneurons in humans. Inhibitory postsynaptic potentials cannot be recorded non-invasively, at least in a pure form, in humans. We herein sought to clarify whether prepulse inhibition (PPI) in the auditory cortex reflected inhibition via interneurons using magnetoencephalography. An abrupt increase in sound pressure by 10 dB in a continuous sound was used to evoke the test response, and PPI was observed by inserting a weak (5 dB increase for 1 ms) prepulse. The time course of the inhibition evaluated by prepulses presented at 10–800 ms before the test stimulus showed at least two temporally distinct inhibitions peaking at approximately 20–60 and 600 ms that presumably reflected IPSPs by fast spiking, parvalbumin-positive cells and somatostatin-positive, Martinotti cells, respectively. In another experiment, we confirmed that the degree of the inhibition depended on the strength of the prepulse, but not on the amplitude of the prepulse-evoked cortical response, indicating that the prepulse-evoked excitatory response and prepulse-evoked inhibition reflected activation in two different pathways. Although many diseases such as schizophrenia may involve deficits in the inhibitory system, we do not have appropriate methods to evaluate them; therefore, the easy and non-invasive method described herein may be clinically useful. PMID:27219470

  14. BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL TROPHOBLAST DIFFERENTIATION

    EPA Science Inventory

    BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL
    TROPHOBLAST DIFFERENTIATION
    Jiangang Chen, Twanda L. Thirkill, Peter N. Lohstroh, Susan R. Bielmeier, Michael
    G. Narotsky, Deborah S. Best, Randy A. Harrison, Kala Natarajan, Rex A. Pegram,
    Bill L. Lasley, and Gordon C. Do...

  15. BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL TROPHOBLAST DIFFERENTIATION

    EPA Science Inventory

    BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL
    TROPHOBLAST DIFFERENTIATION
    Jiangang Chen, Twanda L. Thirkill, Peter N. Lohstroh, Susan R. Bielmeier, Michael
    G. Narotsky, Deborah S. Best, Randy A. Harrison, Kala Natarajan, Rex A. Pegram,
    Bill L. Lasley, and Gordon C. Do...

  16. Inhibition of human aromatase by myosmine.

    PubMed

    Doering, Irene L; Richter, Elmar

    2009-04-01

    Myosmine, a minor tobacco alkaloid widely occurring in food products of plant and animal origin, inhibits the conversion of testosterone to estradiol by human aromatase (IC(50): 33+/-2 microM) sevenfold more potent than nicotine (IC(50): 223+/-10 microM) and may have implications for sexual hormone homoeostasis.

  17. Hawthorn extract inhibits human isolated neutrophil functions.

    PubMed

    Dalli, Ernesto; Milara, Javier; Cortijo, Julio; Morcillo, Esteban J; Cosín-Sales, Juan; Sotillo, José Francisco

    2008-06-01

    Hawthorn extract is a popular herbal medicine given as adjunctive treatment for chronic heart failure. In contrast to the cardiac properties of hawthorn extract, its anti-inflammatory effect has been scarcely investigated. This study examines the effects of a dry extract of leaves and flowers of Crataegus laevigata on various functional outputs of human neutrophils in vitro. Incubation of human neutrophils obtained from peripheral blood of healthy donors with C. laevigata extract (0.75-250 microg/ml) inhibited N-formyl-Met-Leu-Phe (FMLP)-induced superoxide anion generation, elastase release and chemotactic migration with potency values of 43.6, 21.9, and 31.6 microg/ml, respectively. By contrast, serum-opsonized zymosan-induced phagocytosis was unaltered by plant extract. C. laevigata extract (125 microg/ml) reduced FMLP-induced leukotriene B(4) production and lipopolysaccharide-induced generation of tumour necrosis factor-alpha and interleukin-8. Extract inhibited FMLP-induced intracellular calcium signal with potency of 17.4 microg/ml. Extract also markedly inhibited the extracellular calcium entry into calcium-depleted neutrophils, and the thapsigargin-induced intracellular calcium response. In conclusion, C. laevigata extract inhibited various functional outputs of activated human neutrophils which may be relevant to the pathophysiology of cardiac failure.

  18. Antiretrovirals inhibit arginase in human microglia.

    PubMed

    Lisi, Lucia; Laudati, Emilia; Miscioscia, Teresa F; Dello Russo, Cinzia; Topai, Alessandra; Navarra, Pierluigi

    2016-01-01

    Preliminary evidence in an animal model, that is, primary cultures of rat microglia cells, suggested that some antiretroviral drugs (ARVs), namely darunavir, atazanavir, efavirenz, and nevirapine, increase NO production through a mechanism involving the inhibition of arginase (ARG) activity. This study was conceived to investigate the effects of ARVs on ARG activity in a human experimental model. We compared CHME-5 human microglial immortalized cells under basal conditions with cells exposed to either IL-4, a mix of inflammatory cytokines, or both stimuli given together. We also tested the effects of ARVs on CHME-5 cell lysates after exposure to the above stimuli. Moreover, the interaction between the ARVs and ARG was investigated via computational chemistry. We found that ARVs consistently inhibit ARG activity both in intact and lysed cells. In docking studies, darunavir and atazanavir showed similar scores compared with both l-arginine and the ARG antagonist nor-NOHA. Efavirenz and nevirapine, which are less potent in inhibiting ARG in the biochemical assay, also had lower scores. In conclusion, the present findings in a human model support the notion that ARG pathway can present a new, additional molecular target for different ARVs in HIV treatments. We found that antiretroviral drugs (ARVs) consistently inhibit arginase (ARG)-I activity both in intact and lysed cells. In docking studies, darunavir (DRV) and atazanavir (ATV) showed similar scores compared to both l-arginine and the ARG antagonist, Nω-hydroxy-nor-arginine (nor-NOHA). Efavirenz (EFV) and nevirapine (NVP), which are less potent in inhibiting ARG in the biochemical assay, also had lower scores. In conclusion, the present findings in a human model support the notion that ARG pathway can be envisioned as an additional and new molecular target of different ARVs in HIV treatments.

  19. Allosteric inhibition of human porphobilinogen synthase.

    PubMed

    Lawrence, Sarah H; Ramirez, Ursula D; Selwood, Trevor; Stith, Linda; Jaffe, Eileen K

    2009-12-18

    Porphobilinogen synthase (PBGS) catalyzes the first common step in tetrapyrrole (e.g. heme, chlorophyll) biosynthesis. Human PBGS exists as an equilibrium of high activity octamers, low activity hexamers, and alternate dimer configurations that dictate the stoichiometry and architecture of further assembly. It is posited that small molecules can be found that inhibit human PBGS activity by stabilizing the hexamer. Such molecules, if present in the environment, could potentiate disease states associated with reduced PBGS activity, such as lead poisoning and ALAD porphyria, the latter of which is associated with human PBGS variants whose quaternary structure equilibrium is shifted toward the hexamer (Jaffe, E. K., and Stith, L. (2007) Am. J. Hum. Genet. 80, 329-337). Hexamer-stabilizing inhibitors of human PBGS were identified using in silico prescreening (docking) of approximately 111,000 structures to a hexamer-specific surface cavity of a human PBGS crystal structure. Seventy-seven compounds were evaluated in vitro; three provided 90-100% conversion of octamer to hexamer in a native PAGE mobility shift assay. Based on chemical purity, two (ML-3A9 and ML-3H2) were subjected to further evaluation of their effect on the quaternary structure equilibrium and enzymatic activity. Naturally occurring ALAD porphyria-associated human PBGS variants are shown to have an increased susceptibility to inhibition by both ML-3A9 and ML-3H2. ML-3H2 is a structural analog of amebicidal drugs, which have porphyria-like side effects. Data support the hypothesis that human PBGS hexamer stabilization may explain these side effects. The current work identifies allosteric ligands of human PBGS and, thus, identifies human PBGS as a medically relevant allosteric enzyme.

  20. Allosteric Inhibition of Human Porphobilinogen Synthase*

    PubMed Central

    Lawrence, Sarah H.; Ramirez, Ursula D.; Selwood, Trevor; Stith, Linda; Jaffe, Eileen K.

    2009-01-01

    Porphobilinogen synthase (PBGS) catalyzes the first common step in tetrapyrrole (e.g. heme, chlorophyll) biosynthesis. Human PBGS exists as an equilibrium of high activity octamers, low activity hexamers, and alternate dimer configurations that dictate the stoichiometry and architecture of further assembly. It is posited that small molecules can be found that inhibit human PBGS activity by stabilizing the hexamer. Such molecules, if present in the environment, could potentiate disease states associated with reduced PBGS activity, such as lead poisoning and ALAD porphyria, the latter of which is associated with human PBGS variants whose quaternary structure equilibrium is shifted toward the hexamer (Jaffe, E. K., and Stith, L. (2007) Am. J. Hum. Genet. 80, 329–337). Hexamer-stabilizing inhibitors of human PBGS were identified using in silico prescreening (docking) of ∼111,000 structures to a hexamer-specific surface cavity of a human PBGS crystal structure. Seventy-seven compounds were evaluated in vitro; three provided 90–100% conversion of octamer to hexamer in a native PAGE mobility shift assay. Based on chemical purity, two (ML-3A9 and ML-3H2) were subjected to further evaluation of their effect on the quaternary structure equilibrium and enzymatic activity. Naturally occurring ALAD porphyria-associated human PBGS variants are shown to have an increased susceptibility to inhibition by both ML-3A9 and ML-3H2. ML-3H2 is a structural analog of amebicidal drugs, which have porphyria-like side effects. Data support the hypothesis that human PBGS hexamer stabilization may explain these side effects. The current work identifies allosteric ligands of human PBGS and, thus, identifies human PBGS as a medically relevant allosteric enzyme. PMID:19812033

  1. Nitric oxide inhibition of human sperm motility.

    PubMed

    Weinberg, J B; Doty, E; Bonaventura, J; Haney, A F

    1995-08-01

    To determine the effect of nitric oxide (NO) on sperm motility in vitro. Normal human sperm separated by centrifugation through a discontinuous Percoll gradient and subsequent swim-up were incubated for up to 24 hours with NO donors, with and without the known NO quencher hemoglobin, as well as with agents that raise intracellular cyclic 3',5'-guanosine monophosphate (cGMP). Sperm respiration was determined by a tetrazolium-formazan spectrophotometric assay. Andrology laboratory. Absolute sperm motility and respiration. Sperm incubated with the NO donors 1 mM nitroprusside, 100 to 125 microM 3-morpholinosydnonimine, and 25 to 125 microM pure nitric oxide gas dissolved in buffer were inhibited in motility in a dose-dependent fashion. The inhibition could be reversed by the NO quencher hemoglobin. Agents that raise cellular cGMP (dibutyryl cGMP or 8-bromo-cGMP) did not inhibit motility. Nitric oxide inhibited sperm respiration, as measured by the tetrazolium-formazan assay. Nitric oxide reduces sperm motility, possibly by a mechanism involving inhibition of cellular respiration independent of an elevation of intracellular cGMP. Nitric oxide elaborated in the female or male genital tract in vivo could adversely influence sperm function and fertility.

  2. Dimethylphosphoryl-inhibited human cholinesterases: inhibition, reactivation, and aging kinetics.

    PubMed

    Worek, F; Diepold, C; Eyer, P

    1999-02-01

    Human poisoning by organophosphates bearing two methoxy groups, e.g. by malathion, paraoxon-methyl, dimethoate and oxydemeton-methyl, is generally considered to be rather resistant to oxime therapy. Since the oxime effectiveness is influenced not only by its reactivating potential but also by inhibition, aging and spontaneous reactivation kinetics, experiments were performed with human acetyl- (AChE) and butyrylcholinesterase (BChE) to determine the respective kinetic constants. The efficacy of obidoxime in reactivating dimethylphosphoryl-AChE was 40, 9 and 3 times higher than of HI 6, pralidoxime and HLö 7, respectively. Aging (t1/2 3.7 h) and spontaneous reactivation (t1/2 0.7 h) occurred concomitantly, with the portion of the aged enzyme being dependent on the presence of excess inhibitor. Calculation of steady-state AChE activity in the presence of inhibitor and oxime revealed that obidoxime was superior to pralidoxime. In addition, organophosphate concentrations up to 10(-6) M (paraoxon-methyl) and 10(-4) M (oxydemeton-methyl) could be counteracted at clinically relevant oxime concentrations (10 microM). These data indicate that oximes may effectively reactivate human dimethylphosphoryl-AChE. Failure of oximes may be attributed to megadose intoxications and to prolonged time intervals between poison uptake and oxime administration. The potency of the oximes to reactivate dimethylphosphoryl-BChE was much lower and the spontaneous reactivation slower (t1/2 9 h), while aging proceeded at a comparable rate. Thus, BChE activity determination for diagnosis and therapeutic monitoring may give no reliable information on AChE status.

  3. Wnt modulating agents inhibit human cytomegalovirus replication.

    PubMed

    Kapoor, Arun; He, Ran; Venkatadri, Rajkumar; Forman, Michael; Arav-Boger, Ravit

    2013-06-01

    Infection with human cytomegalovirus (HCMV) continues to be a threat for pregnant women and immunocompromised hosts. Although limited anti-HCMV therapies are available, development of new agents is desired. The Wnt signaling pathway plays a critical role in embryonic and cancer stem cell development and is targeted by gammaherpesviruses, Epstein-Barr virus (EBV), and Kaposi's sarcoma-associated herpesvirus (KSHV). HCMV infects stem cells, including neural progenitor cells, during embryogenesis. To investigate the role of Wnt in HCMV replication in vitro, we tested monensin, nigericin, and salinomycin, compounds that inhibit cancer stem cell growth by modulating the Wnt pathway. These compounds inhibited the replication of HCMV Towne and a clinical isolate. Inhibition occurred prior to DNA replication but persisted throughout the full replication cycle. There was a significant decrease in expression of IE2, UL44, and pp65 proteins. HCMV infection resulted in a significant and sustained decrease in expression of phosphorylated and total lipoprotein receptor-related protein 6 (pLRP6 and LRP6, respectively), Wnt 5a/b, and β-catenin and a modest decrease in Dvl2/3, while levels of the negative regulator axin 1 were increased. Nigericin decreased the expression of pLRP6, LRP6, axin 1, and Wnt 5a/b in noninfected and HCMV-infected cells. For all three compounds, a correlation was found between expression levels of Wnt 5a/b and axin 1 and HCMV inhibition. The decrease in Wnt 5a/b and axin 1 expression was more significant in HCMV-infected cells than noninfected cells. These data illustrate the complex effects of HCMV on the Wnt pathway and the fine balance between Wnt and HCMV, resulting in abrogation of HCMV replication. Additional studies are required to elucidate how HCMV targets Wnt for its benefit.

  4. Wnt Modulating Agents Inhibit Human Cytomegalovirus Replication

    PubMed Central

    Kapoor, Arun; He, Ran; Venkatadri, Rajkumar; Forman, Michael

    2013-01-01

    Infection with human cytomegalovirus (HCMV) continues to be a threat for pregnant women and immunocompromised hosts. Although limited anti-HCMV therapies are available, development of new agents is desired. The Wnt signaling pathway plays a critical role in embryonic and cancer stem cell development and is targeted by gammaherpesviruses, Epstein-Barr virus (EBV), and Kaposi's sarcoma-associated herpesvirus (KSHV). HCMV infects stem cells, including neural progenitor cells, during embryogenesis. To investigate the role of Wnt in HCMV replication in vitro, we tested monensin, nigericin, and salinomycin, compounds that inhibit cancer stem cell growth by modulating the Wnt pathway. These compounds inhibited the replication of HCMV Towne and a clinical isolate. Inhibition occurred prior to DNA replication but persisted throughout the full replication cycle. There was a significant decrease in expression of IE2, UL44, and pp65 proteins. HCMV infection resulted in a significant and sustained decrease in expression of phosphorylated and total lipoprotein receptor-related protein 6 (pLRP6 and LRP6, respectively), Wnt 5a/b, and β-catenin and a modest decrease in Dvl2/3, while levels of the negative regulator axin 1 were increased. Nigericin decreased the expression of pLRP6, LRP6, axin 1, and Wnt 5a/b in noninfected and HCMV-infected cells. For all three compounds, a correlation was found between expression levels of Wnt 5a/b and axin 1 and HCMV inhibition. The decrease in Wnt 5a/b and axin 1 expression was more significant in HCMV-infected cells than noninfected cells. These data illustrate the complex effects of HCMV on the Wnt pathway and the fine balance between Wnt and HCMV, resulting in abrogation of HCMV replication. Additional studies are required to elucidate how HCMV targets Wnt for its benefit. PMID:23571549

  5. Interleukin 27R regulates CD4+ T cell phenotype and impacts protective immunity during Mycobacterium tuberculosis infection

    PubMed Central

    Torrado, Egidio; Fountain, Jeffrey J.; Liao, Mingfeng; Tighe, Michael; Reiley, William W.; Lai, Rachel P.; Meintjes, Graeme; Pearl, John E.; Chen, Xinchun; Zak, Daniel E.; Thompson, Ethan G.; Aderem, Alan; Ghilardi, Nico; Solache, Alejandra; McKinstry, K. Kai; Strutt, Tara M.; Wilkinson, Robert J.; Swain, Susan L.

    2015-01-01

    CD4+ T cells mediate protection against Mycobacterium tuberculosis (Mtb); however, the phenotype of protective T cells is undefined, thereby confounding vaccination efforts. IL-27 is highly expressed during human tuberculosis (TB), and absence of IL-27R (Il27ra) specifically on T cells results in increased protection. IL-27R deficiency during chronic Mtb infection does not impact antigen-specific CD4+ T cell number but maintains programmed death-1 (PD-1), CD69, and CD127 expression while reducing T-bet and killer cell lectin-like receptor G1 (KLRG1) expression. Furthermore, T-bet haploinsufficiency results in failure to generate KLRG1+, antigen-specific CD4+ T cells, and in improved protection. T cells in Il27ra−/− mice accumulate preferentially in the lung parenchyma within close proximity to Mtb, and antigen-specific CD4+ T cells lacking IL-27R are intrinsically more fit than intact T cells and maintain IL-2 production. Improved fitness of IL-27R–deficient T cells is not associated with increased proliferation but with decreased expression of cell death–associated markers. Therefore, during Mtb infection, IL-27R acts intrinsically on T cells to limit protection and reduce fitness, whereas the IL-27R–deficient environment alters the phenotype and location of T cells. The significant expression of IL-27 in TB and the negative influence of IL-27R on T cell function demonstrate the pathway by which this cytokine/receptor pair is detrimental in TB. PMID:26282876

  6. PCB126 Inhibits Adipogenesis of Human Preadipocytes

    PubMed Central

    Gadupudi, Gopi; Gourronc, Francoise A.; Ludewig, Gabriele; Robertson, Larry W.; Klingelhutz, Aloysius J.

    2014-01-01

    Emerging evidence indicates that persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), are involved in the development of diabetes. Dysfunctional adipocytes play a significant role in initiating insulin resistance. Preadipocytes make up a large portion of adipose tissue and are necessary for the generation of functional mature adipocytes through adipogenesis. PCB126 is a dioxin-like PCB and a potent aryl hydrocarbon receptor (AhR) agonist. We hypothesized that PCB126 may be involved in the development of diabetes through disruption of adipogenesis. Using a newly developed human preadipocyte cell line called NPAD (Normal PreADipocytes), we found that exposure of preadipocytes to PCB126 resulted in significant reduction in their subsequent ability to fully differentiate into adipocytes, more so than when the cells were exposed to PCB126 during differentiation. Reduction in differentiation by PCB126 was associated with downregulation of transcript levels of a key adipocyte transcription factor, PPARγ, and late adipocyte differentiation genes. An AhR antagonist, CH223191, blocked this effect. These studies indicate that preadipocytes are particularly sensitive to the effects of PCB126 and suggest that AhR activation inhibits PPARγ transcription and subsequent adipogenesis. Our results validate the NPAD cell line as a useful model for studying the effects of POPs on adipogenesis. PMID:25304490

  7. Interleukin 27 -964A > G genetic polymorphism and serum IL-27p28 levels in Chinese patients with papillary thyroid cancer.

    PubMed

    Zhang, Shulong; Gao, Xueren; Wang, Yong; Jia, Jianguang; Zhang, Qiang; Ji, Zhenling

    2015-09-01

    The aim of this study was to investigate the association between a potentially functional polymorphism (rs153109, -964A > G) in the promoter region of interleukin-27 (IL-27) gene and the risk of papillary thyroid cancer (PTC) in a Chinese population. Genotype of IL-27 -964A > G polymorphism was determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Serum IL-27p28 levels were determined using enzyme-linked immunosorbent assay (ELISA). No significant difference was noticed in IL-27 -964A > G polymorphism between PTC patients and healthy controls in the overall analysis. However, analysis of clinical features showed that PTC patients carrying the GG genotype or G allele had significantly decreased risks for developing lymph node metastasis compared with those carrying the AA genotype or A allele (GG vs. AA: OR = 0.38, 95 % CI, 0.20-0.72; G vs. A: OR = 0.63, 95 % CI, 0.44-0.86). Furthermore, ELISA results demonstrated that serum IL-27p28 levels were significantly decreased in PTC patients compared with those in controls (P < 0.05). Serum IL-27p28 levels in healthy controls with the GG genotype were significantly high compared with those carrying AA genotype or the AG genotype (P < 0.05). In conclusion, our results suggest that IL-27 -964A > G polymorphism may be associated with the decreased risk for lymph node metastasis of PTC.

  8. Pain inhibits pain; human brainstem mechanisms.

    PubMed

    Youssef, A M; Macefield, V G; Henderson, L A

    2016-01-01

    Conditioned pain modulation is a powerful analgesic mechanism, occurring when a painful stimulus is inhibited by a second painful stimulus delivered at a different body location. Reduced conditioned pain modulation capacity is associated with the development of some chronic pain conditions and the effectiveness of some analgesic medications. Human lesion studies show that the circuitry responsible for conditioned pain modulation lies within the caudal brainstem, although the precise nuclei in humans remain unknown. We employed brain imaging to determine brainstem sites responsible for conditioned pain modulation in 54 healthy individuals. In all subjects, 8 noxious heat stimuli (test stimuli) were applied to the right side of the mouth and brain activity measured using functional magnetic resonance imaging. This paradigm was then repeated. However, following the fourth noxious stimulus, a separate noxious stimulus, consisting of an intramuscular injection of hypertonic saline into the leg, was delivered (conditioning stimulus). During this test and conditioning stimulus period, 23 subjects displayed conditioned pain modulation analgesia whereas 31 subjects did not. An individual's analgesic ability was not influenced by gender, pain intensity levels of the test or conditioning stimuli or by psychological variables such as pain catastrophizing or fear of pain. Brain images were processed using SPM8 and the brainstem isolated using the SUIT toolbox. Significant increases in signal intensity were determined during each test stimulus and compared between subjects that did and did not display CPM analgesia (p<0.05, small volume correction). The expression of analgesia was associated with reduction in signal intensity increases during each test stimulus in the presence of the conditioning stimulus in three brainstem regions: the caudalis subdivision of the spinal trigeminal nucleus, i.e., the primary synapse, the region of the subnucleus reticularis dorsalis and in the

  9. Allosteric Inhibition of Human Immunodeficiency Virus Integrase

    PubMed Central

    Gupta, Kushol; Brady, Troy; Dyer, Benjamin M.; Malani, Nirav; Hwang, Young; Male, Frances; Nolte, Robert T.; Wang, Liping; Velthuisen, Emile; Jeffrey, Jerry; Van Duyne, Gregory D.; Bushman, Frederic D.

    2014-01-01

    HIV-1 replication in the presence of antiviral agents results in evolution of drug-resistant variants, motivating the search for additional drug classes. Here we report studies of GSK1264, which was identified as a compound that disrupts the interaction between HIV-1 integrase (IN) and the cellular factor lens epithelium-derived growth factor (LEDGF)/p75. GSK1264 displayed potent antiviral activity and was found to bind at the site occupied by LEDGF/p75 on IN by x-ray crystallography. Assays of HIV replication in the presence of GSK1264 showed only modest inhibition of the early infection steps and little effect on integration targeting, which is guided by the LEDGF/p75·IN interaction. In contrast, inhibition of late replication steps was more potent. Particle production was normal, but particles showed reduced infectivity. GSK1264 promoted aggregation of IN and preformed LEDGF/p75·IN complexes, suggesting a mechanism of inhibition. LEDGF/p75 was not displaced from IN during aggregation, indicating trapping of LEDGF/p75 in aggregates. Aggregation assays with truncated IN variants revealed that a construct with catalytic and C-terminal domains of IN only formed an open polymer associated with efficient drug-induced aggregation. These data suggest that the allosteric inhibitors of IN are promising antiviral agents and provide new information on their mechanism of action. PMID:24904063

  10. Recombinant human gamma interferon inhibits simian malaria.

    PubMed Central

    Maheshwari, R K; Czarniecki, C W; Dutta, G P; Puri, S K; Dhawan, B N; Friedman, R M

    1986-01-01

    Prophylactic treatment with 0.1 mg of human gamma interferon per kg (body weight) per day completely suppressed experimental infection with Plasmodium cynomolgi B sporozoites in rhesus monkeys. Treatment with lower doses partially suppressed this infection. Prophylactic treatment with human gamma interferon, however, had no protective effect against trophozoite-induced infection, suggesting that the interferon effect was limited to the exoerythrocytic stage of parasitic development. PMID:3091507

  11. Tonic inhibition of chemotaxis in human plasma

    PubMed Central

    Malawista, Stephen E.; de Boisfleury Chevance, Anne; van Damme, Jo; Serhan, Charles N.

    2008-01-01

    We found exaggerated chemotaxis in plasma treated with EDTA and thought that the EDTA might itself be inhibiting a tonic inhibitor(s) of chemotaxis. Our plasma fractionations suggested that evidence should be sought for a lipid moiety carrying this activity, and on spectrometry (LC-MS-MS together with GC-MS analyses), the biologically active but not the inactive fraction contained oleic and arachidonic acids. Because fatty acids are largely protein bound, we flooded plasma preparations with delipidated albumin, reasoning that it would bind enough fatty acids, including inhibitory ones, to counter their tonic inhibition. Indeed, we observed dramatic increases in chemotaxis. Hence, adding delipidated albumin to plasma has a similar effect to that of adding EDTA—amplification of the chemotactic response. Oleic acid in physiologic concentrations diminishes the magnifying effects of both EDTA and of delipidated albumin, and in fact diminishes the chemotactic response even without the presence of the amplifiers of chemotaxis. In contrast, arachidonic acid amplifies further the effect of EDTA but not of delipidated albumin, and this augmentation appears to be caused by an EDTA-dependent enrichment of the chemotactic gradient with leukotriene B4 (LTB4). We conclude that oleic acid, the blood levels of which vary among individuals, is at least one tonic inhibitor of chemotaxis in plasma. PMID:18997012

  12. Bee venom inhibits growth of human cervical tumors in mice

    PubMed Central

    Kim, Tae Myoung; Jung, Yu Yeon; Park, Mi Hee; Oh, Sang Hyun; Yun, Hye Seok; Jun, Hyung Ok; Yoo, Hwan Soo; Han, Sang-Bae; Lee, Ung Soo; Yoon, Joo Hee; Song, Min Jong; Hong, Jin Tae

    2015-01-01

    We studied whether bee venom (BV) inhibits cervical tumor growth through enhancement of death receptor (DR) expressions and inactivation of nuclear factor kappa B (NF-κB) in mice. In vivo study showed that BV (1 mg/kg) inhibited tumor growth. Similar inhibitory effects of BV on cancer growth in primary human cervical cancer cells were also found. BV (1–5 μg/ml) also inhibited the growth of cancer cells, Ca Ski and C33Aby the induction of apoptotic cell death in a dose dependent manner. Agreed with cancer cell growth inhibition, expression of death receptors; FAS, DR3 and DR6, and DR downstream pro-apoptotic proteins including caspase-3 and Bax was concomitantly increased, but the NF-κB activity and the expression of Bcl-2 were inhibited by treatment with BV in tumor mice, human cancer cell and human tumor samples as well as cultured cancer cells. In addition, deletion of FAS, DR3 and DR6 by small interfering RNA significantly reversed BV-induced cell growth inhibitory effects as well as NF-κB inactivation. These results suggest that BV inhibits cervical tumor growth through enhancement of FAS, DR3 and DR6 expression via inhibition of NF-κB pathway. PMID:25730901

  13. Identification of Interleukin-27 (IL-27)/IL-27 Receptor Subunit Alpha as a Critical Immune Axis for In Vivo HIV Control.

    PubMed

    Ruiz-Riol, M; Berdnik, D; Llano, A; Mothe, B; Gálvez, C; Pérez-Álvarez, S; Oriol-Tordera, B; Olvera, A; Silva-Arrieta, S; Meulbroek, M; Pujol, F; Coll, J; Martinez-Picado, J; Ganoza, C; Sanchez, J; Gómez, G; Wyss-Coray, T; Brander, C

    2017-08-15

    Intact and broad immune cell effector functions and specific individual cytokines have been linked to HIV disease outcome, but their relative contribution to HIV control remains unclear. We asked whether the proteome of secreted cytokines and signaling factors in peripheral blood can be used to discover specific pathways critical for host viral control. A custom glass-based microarray, able to measure >600 plasma proteins involved in cell-to-cell communication, was used to measure plasma protein profiles in 96 HIV-infected, treatment-naive individuals with high (>50,000) or low (<10,000 HIV RNA copies/ml) viral loads. Univariate and regression model analysis demonstrate that plasma levels of soluble interleukin-27 (IL-27) are significantly elevated in individuals with high plasma viremia (P < 0.0001) and are positively correlated with proviral HIV-DNA copy numbers in peripheral blood mononuclear cells (PBMC) (Rho = 0.4011; P = 0.0027). Moreover, soluble IL-27 plasma levels are negatively associated with the breadth and magnitude of the total virus-specific T-cell responses and directly with plasma levels of molecules involved in Wnt/β-catenin signaling. In addition to IL-27, gene expression levels of the specific IL-27 receptor (IL27RA) in PBMC correlated directly with both plasma viral load (Rho = 0.3531; P = 0.0218) and the proviral copy number in the peripheral blood as an indirect measure of partial viral reservoir (Rho = 0.4580; P = 0.0030). These results were validated in unrelated cohorts of early infected subjects as well as subjects before and after initiation of antiretroviral treatment, and they identify IL-27 and its specific receptor as a critical immune axis for the antiviral immune response and as robust correlates of viral load and proviral reservoir size in PBMC.IMPORTANCE The detailed knowledge of immune mechanisms that contribute to HIV control is a prerequisite for the design of effective treatment strategies to achieve HIV cure. Cells

  14. Inhibition of human papillomavirus expression using DNAzymes.

    PubMed

    Benítez-Hess, María Luisa; Reyes-Gutiérrez, Pablo; Alvarez-Salas, Luis Marat

    2011-01-01

    Deoxyribozymes (DXZs) are catalytic oligodeoxynucleotides capable of performing diverse functions including the specific cleavage of a target RNA. These molecules represent a new type of therapeutic oligonucleotides combining the efficiency of ribozymes and the intracellular endurance and simplicity of modified antisense oligonucleotides. Commonly used DXZs include the 8-17 and 10-23 motifs, which have been engineered to destroy disease-associated genes with remarkable efficiency. Targeting DXZs to disease-associated transcripts requires extensive biochemical testing to establish target RNA accessibility, catalytic efficiency, and nuclease sensibility. The usage of modified nucleotides to render nuclease-resistance DXZs must be counterweighted against deleterious consequences on catalytic activity. Further intracellular testing is required to establish the effect of microenvironmental conditions on DXZ activity and off-target issues. Application of modified DXZs to cervical cancer results in specific growth inhibition, cell death, and apoptosis. Thus, DXZs represent a highly effective antisense moiety with minimal secondary effects.

  15. Genistein suppresses FLT4 and inhibits human colorectal cancer metastasis.

    PubMed

    Xiao, Xiao; Liu, Zhiguo; Wang, Rui; Wang, Jiayin; Zhang, Song; Cai, Xiqiang; Wu, Kaichun; Bergan, Raymond C; Xu, Li; Fan, Daiming

    2015-02-20

    Dietary consumption of genistein, found in soy, has been associated with a potentially protective role in colorectal cancer (CRC) development and progression. Herein we demonstrate that genistein will inhibit human CRC cell invasion and migration, that it does so at non-cytotoxic concentrations and we demonstrate this in multiple human CRC cell lines. After orthotopic implantation of human CRC tumors into mice, oral genistein did not inhibit tumor growth, but did inhibit distant metastasis formation, and was non-toxic to mice. Using a qPCR array, we screened for genistein-induced changes in gene expression, followed by Western blot confirmation, demonstrating that genistein downregulated matrix metalloproteinase 2 and Fms-Related Tyrosine Kinase 4 (FLT4; vascular endothelial growth factor receptor 3). After demonstrating that genistein suppressed neo-angiogenesis in mouse tumors, we examined FLT4 expression in primary CRC and adjacent normal colonic tissue from 60 human subjects, demonstrating that increased FLT4 significantly correlates with increased stage and decreased survival. In summary, we demonstrate for the first time that genistein inhibits human CRC metastasis at dietary, non-toxic, doses. FLT4 is identified as a marker of metastatic disease, and as a response marker for small molecule therapeutics that inhibit CRC metastasis.

  16. Inhibition of Human Neutrophil Elastase by Pentacyclic Triterpenes

    PubMed Central

    Feng, Li; Liu, Xiaoyu; Zhu, Weiliang; Guo, Fujiang; YingchunWu; Wang, Rui; Chen, Kaixian; Huang, Cheng; Li, Yiming

    2013-01-01

    Scope Inhibiting human neutrophil elastase (HNE) is a promising strategy for treating inflammatory lung diseases, such as H1N1 and SARS virus infections. The use of sivelestat, the only clinically registered synthesized HNE inhibitor, is largely limited by its risk of organ toxicity because it irreversibly inhibits HNE. Therefore, potent reversible HNE inhibitors are promising alternatives to sivelestat. Methods and Results An in vitro HNE inhibition assay was employed to screen a series of triterpenes. Six pentacyclic triterpenes, but not tetracyclic triterpenes, significantly inhibited HNE. Of these pentacyclic triterpenes, ursolic acid exhibited the highest inhibitory potency (IC50 = 5.51 µM). The HNE inhibitory activity of ursolic acid was further verified using a mouse model of acute smoke-induced lung inflammation. The results of nuclear magnetic resonance and HNE inhibition kinetic analysis showed that the pentacyclic triterpenes competitively and reversibly inhibited HNE. Molecular docking experiments indicated that the molecular scaffold, 28-COOH, and a double bond at an appropriate location in the pentacyclic triterpenes are important for their inhibitory activity. Conclusion Our results provide insights into the effects of pentacyclic triterpenes on lung inflammatory actions through reversible inhibition of HNE activity. PMID:24376583

  17. Inhibition of human neutrophil elastase by pentacyclic triterpenes.

    PubMed

    Feng, Li; Liu, Xiaoyu; Zhu, Weiliang; Guo, Fujiang; Wu, Yingchun; Wang, Rui; Chen, Kaixian; Huang, Cheng; Li, Yiming

    2013-01-01

    Inhibiting human neutrophil elastase (HNE) is a promising strategy for treating inflammatory lung diseases, such as H1N1 and SARS virus infections. The use of sivelestat, the only clinically registered synthesized HNE inhibitor, is largely limited by its risk of organ toxicity because it irreversibly inhibits HNE. Therefore, potent reversible HNE inhibitors are promising alternatives to sivelestat. An in vitro HNE inhibition assay was employed to screen a series of triterpenes. Six pentacyclic triterpenes, but not tetracyclic triterpenes, significantly inhibited HNE. Of these pentacyclic triterpenes, ursolic acid exhibited the highest inhibitory potency (IC50 = 5.51 µM). The HNE inhibitory activity of ursolic acid was further verified using a mouse model of acute smoke-induced lung inflammation. The results of nuclear magnetic resonance and HNE inhibition kinetic analysis showed that the pentacyclic triterpenes competitively and reversibly inhibited HNE. Molecular docking experiments indicated that the molecular scaffold, 28-COOH, and a double bond at an appropriate location in the pentacyclic triterpenes are important for their inhibitory activity. Our results provide insights into the effects of pentacyclic triterpenes on lung inflammatory actions through reversible inhibition of HNE activity.

  18. Inhibition of human polymorphonuclear leukocyte chemotaxis by oxygenated sterol compounds

    SciTech Connect

    Gordon, L.I.; Bass, J.; Yachnin, S.

    1980-07-01

    When preincubated with certain oxygenated sterol compounds in lipoprotein-depleted serum (20% (vol/vol)), human polymorphonuclear leukocytes show inhibition of chemotaxis toward the synthetic dipeptide N-formylmethionylphenylalinine without alteration of random movement or loss of cell viability. These effects can occur at sterol concentrations as low as 6.25 ..mu..M and after as little as 5 min of preincubation, but they are increased at higher concentrations and longer preincubation times. The inhibition can be almost completely reversed by preincubation in lipoprotein-replete serum (human AB serum, 20% (vol/vol)) and may be partially corrected by addition of free cholesterol (0.125 mM) to the medium. These effects are unlikely to be due to inhibition of cellular sterol synthesis, competition for chemotaxin membrane binding sites, or deactivation of the leukocytes but they may be a consequence of insertion of the sterol molecule into the leukocyte plasma membranes.

  19. The endogenous cannabinoid anandamide inhibits human breast cancer cell proliferation

    PubMed Central

    De Petrocellis, Luciano; Melck, Dominique; Palmisano, Antonella; Bisogno, Tiziana; Laezza, Chiara; Bifulco, Maurizio; Di Marzo, Vincenzo

    1998-01-01

    Anandamide was the first brain metabolite shown to act as a ligand of “central” CB1 cannabinoid receptors. Here we report that the endogenous cannabinoid potently and selectively inhibits the proliferation of human breast cancer cells in vitro. Anandamide dose-dependently inhibited the proliferation of MCF-7 and EFM-19 cells with IC50 values between 0.5 and 1.5 μM and 83–92% maximal inhibition at 5–10 μM. The proliferation of several other nonmammary tumoral cell lines was not affected by 10 μM anandamide. The anti-proliferative effect of anandamide was not due to toxicity or to apoptosis of cells but was accompanied by a reduction of cells in the S phase of the cell cycle. A stable analogue of anandamide (R)-methanandamide, another endogenous cannabinoid, 2-arachidonoylglycerol, and the synthetic cannabinoid HU-210 also inhibited EFM-19 cell proliferation, whereas arachidonic acid was much less effective. These cannabimimetic substances displaced the binding of the selective cannabinoid agonist [3H]CP 55,940 to EFM-19 membranes with an order of potency identical to that observed for the inhibition of EFM-19 cell proliferation. Moreover, anandamide cytostatic effect was inhibited by the selective CB1 receptor antagonist SR 141716A. Cell proliferation was arrested by a prolactin mAb and enhanced by exogenous human prolactin, whose mitogenic action was reverted by very low (0.1–0.5 μM) doses of anandamide. Anandamide suppressed the levels of the long form of the prolactin receptor in both EFM-19 and MCF-7 cells, as well as a typical prolactin-induced response, i.e., the expression of the breast cancer cell susceptibility gene brca1. These data suggest that anandamide blocks human breast cancer cell proliferation through CB1-like receptor-mediated inhibition of endogenous prolactin action at the level of prolactin receptor. PMID:9653194

  20. Hydroxyl radical scavengers inhibit human lectin-dependent cellular cytotoxicity.

    PubMed

    Melinn, M; McLaughlin, H

    1986-06-01

    The role of oxygen-derived free radicals (ODFR) in lectin-dependent cellular cytotoxicity (LDCC) in humans was investigated. The hydroxyl radical traps thiourea, methanol, ethanol and phenol were effective in inhibiting LDCC, as was DABCO, a singlet oxygen quencher. The proposed pathway of hydroxyl radical production in living cells is either an iron catalysed Haber-Weiss reaction or a Fenton reaction. The effect of inhibitors of these pathways was investigated. The superoxide anion scavengers superoxide dismutase, ferricytochrome c and Tiron were without effect. It was shown that Tiron inhibits the lucigenin-amplified chemiluminescence produced by the action of xanthine oxidase, and also the lucigenin-amplified chemiluminescence produced by activated PMN, suggesting that this agent (Tiron) scavenges intracellular superoxide anion. Catalase gave slight inhibition of LDCC only. The ferric iron chelator desferrioxamine gave no protection of the target cells, while the ferrous chelator, 1,10-phenanthroline, inhibited LDCC and partially prevented the detection of hydroxyl radicals generated by the Fe2+-H2O2 system. Cibacron blue, an agent that inhibits NAD(P)H linked enzymes, also inhibited LDCC. The cyclo-oxygenase inhibitors indomethacin and salicylate were without effect, while the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) inhibited cytolysis. None of the LDCC inhibitors was cytotoxic to the effector cells or to the target cells, neither did they inhibit lymphocyte-target binding. The findings would suggest that hydroxyl radicals have a role to play in human T-cell mediated cytolysis, either as the active lytic agent or as an epiphenomenon.

  1. Some Determinants of Latent Inhibition in Human Predictive Learning

    ERIC Educational Resources Information Center

    Pineno, Oskar; de la Casa, Luis Gonzalo; Lubow, R. E.; Miller, Ralph R.

    2006-01-01

    The present experiments assessed the effects of different manipulations between cue preexposure and cue-outcome pairings on latent inhibition (LI) in a predictive learning task with human participants. To facilitate LI, preexposure and acquisition with the target cues took place while participants performed a secondary task. Presentation of…

  2. Ketamine inhibits human sperm function by Ca(2+)-related mechanism.

    PubMed

    He, Yuanqiao; Zou, Qianxing; Li, Bingda; Chen, Houyang; Du, Xiaohong; Weng, Shiqi; Luo, Tao; Zeng, Xuhui

    2016-09-09

    Ketamine, a dissociative anesthetic, which was widely used in human and animal medicine, has become a popular recreational drug, as it can induce hallucinatory effects. Ketamine abuse can cause serious damage to many aspects of the organism, mainly reflected in the nervous system and urinary system. It has also been reported that ketamine can impair the male genital system. However, the detailed effect of ketamine on human spermatozoa remains unclear. Thus, we investigated the in vitro effects of ketamine on human sperm functions, to elucidate the underlying mechanism. Human sperm were treated in vitro with different concentrations of ketamine (0, 0.125, 0.25, 0.5, 1 g/L). The results showed that 0.25-1 g/L ketamine inhibited sperm total motility, progressive motility and linear velocity, in a dose-dependent manner. In addition, the sperm's ability to penetrate viscous medium and the progesterone-induced acrosome reaction were significantly inhibited by ketamine. Ketamine did not affect sperm viability, capacitation and spontaneous acrosome reaction. The intracellular calcium concentration ([Ca(2+)]i), which is a central factor in the regulation of human sperm function, was decreased by ketamine (0.125-1 g/L) in a dose-dependent manner. Furthermore, the currents of the sperm-specific Ca(2+) channel, CatSper, which modulates Ca(2+) influx in sperm, were inhibited by ketamine (0.125-1 g/L) in a dose-dependent manner. Our findings suggest that ketamine induces its toxic effects on human sperm functions by reducing sperm [Ca(2+)]i through inhibition of CatSper channel. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Inhibition of human squalene monooxygenase by selenium compounds.

    PubMed

    Gupta, Nisha; Porter, Todd D

    2002-01-01

    Selenosis in animals is characterized by a variety of neurological abnormalities, but the chemical species of selenium and the molecular targets that mediate this neurotoxicity are unknown. We have previously shown that selenite is a potent inhibitor of squalene monooxygenase, the second enzyme in the committed pathway for cholesterol biosynthesis; inhibition of this enzyme by dimethyltellurium leads to a peripheral demyelinating neuropathy similar to that seen in selenosis. To evaluate the role methylation plays in selenium toxicity, we examined the ability of three methylselenium compounds, methylselenol, dimethylselenide, and trimethylselenonium iodide, to inhibit purified recombinant human squalene monooxygenase. IC(50) values for methylselenol (95 microM) and dimethylselenide (680 microM) were greater than that previously obtained for selenite (37 microM), and inhibition by trimethylselenonium iodide was evident only at concentrations above 3 mM. Inhibition by methylselenol as well as by selenite was slow and irreversible, suggestive of covalent binding to the enzyme, and thiol-containing compounds could prevent and reverse this inhibition, indicating that these compounds were reacting with sulfhydryl groups on the protein. Monothiols such as glutathione and beta-mercaptoethanol provided better protection than did dithiols, suggesting that these selenium compounds bind to only one of the two proposed vicinal cysteines on squalene monooxygenase. Unexpectedly, the inhibition by selenite was significantly enhanced by dithiols, indicating that a more toxic species, possibly selenide, was formed in the presence of these dithiol reductants. Copyright 2002 Wiley Periodicals, Inc.

  4. Effects of lorazepam on short latency afferent inhibition and short latency intracortical inhibition in humans

    PubMed Central

    Di Lazzaro, V; Oliviero, A; Saturno, E; Dileone, M; Pilato, F; Nardone, R; Ranieri, F; Musumeci, G; Fiorilla, T; Tonali, P

    2005-01-01

    Experimental studies have demonstrated that the GABAergic system modulates acetylcholine release and, through GABAA receptors, tonically inhibits cholinergic activity. Little is known about the effects of GABA on the cholinergic activity in the human central nervous system. In vivo evaluation of some cholinergic circuits of the human brain has recently been introduced using a transcranial magnetic stimulation (TMS) protocol based on coupling peripheral nerve stimulation with TMS of the motor cortex. Peripheral nerve inputs have an inhibitory effect on motor cortex excitability at short intervals (short latency afferent inhibition, SAI). We investigated whether GABAA activity enhancement by lorazepam modifies SAI. We also evaluated the effects produced by lorazepam on a different TMS protocol of cortical inhibition, the short interval intracortical inhibition (SICI), which is believed to be directly related to GABAA activity. In 10 healthy volunteers, the effects of lorazepam were compared with those produced by quetiapine, a psychotropic drug with sedative effects with no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors, and with those of a placebo using a randomized double-blind study design. Administration of lorazepam produced a significant increase in SICI (F3,9 = 3.19, P = 0.039). In contrast to SICI, SAI was significantly reduced by lorazepam (F3,9 = 9.39, P = 0.0002). Our findings demonstrate that GABAA activity enhancement determines a suppression of SAI and an increase of SICI. PMID:15718269

  5. Effects of lorazepam on short latency afferent inhibition and short latency intracortical inhibition in humans.

    PubMed

    Di Lazzaro, V; Oliviero, A; Saturno, E; Dileone, M; Pilato, F; Nardone, R; Ranieri, F; Musumeci, G; Fiorilla, T; Tonali, P

    2005-04-15

    Experimental studies have demonstrated that the GABAergic system modulates acetylcholine release and, through GABA(A) receptors, tonically inhibits cholinergic activity. Little is known about the effects of GABA on the cholinergic activity in the human central nervous system. In vivo evaluation of some cholinergic circuits of the human brain has recently been introduced using a transcranial magnetic stimulation (TMS) protocol based on coupling peripheral nerve stimulation with TMS of the motor cortex. Peripheral nerve inputs have an inhibitory effect on motor cortex excitability at short intervals (short latency afferent inhibition, SAI). We investigated whether GABA(A) activity enhancement by lorazepam modifies SAI. We also evaluated the effects produced by lorazepam on a different TMS protocol of cortical inhibition, the short interval intracortical inhibition (SICI), which is believed to be directly related to GABA(A) activity. In 10 healthy volunteers, the effects of lorazepam were compared with those produced by quetiapine, a psychotropic drug with sedative effects with no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors, and with those of a placebo using a randomized double-blind study design. Administration of lorazepam produced a significant increase in SICI (F(3,9) = 3.19, P = 0.039). In contrast to SICI, SAI was significantly reduced by lorazepam (F(3,9) = 9.39, P = 0.0002). Our findings demonstrate that GABA(A) activity enhancement determines a suppression of SAI and an increase of SICI.

  6. Paromomycin inhibits Cryptosporidium infection of a human enterocyte cell line.

    PubMed

    Marshall, R J; Flanigan, T P

    1992-04-01

    Cryptosporidium parvum is a protozoan parasite that causes severe enteritis in patients with AIDS for which there is no effective therapy. Paromomycin is a nonabsorbable aminoglycoside that is effective in the treatment of other intestinal protozoa. The ability of paromomycin to inhibit C. parvum infection of a differentiated human enterocyte cell line was evaluated in vitro. Paromomycin concentrations ranging from 50 to 5000 micrograms/ml inhibited infection at 24 h in a dose-dependent fashion. Concentrations greater than 1000 micrograms/ml, which are theoretically achievable in the bowel lumen, inhibited infection by greater than 85% (P less than .001). Prospective clinical trials of paromomycin for the treatment of cryptosporidiosis in patients with AIDS are warranted.

  7. Boric acid inhibits human prostate cancer cell proliferation.

    PubMed

    Barranco, Wade T; Eckhert, Curtis D

    2004-12-08

    The role of boron in biology includes coordinated regulation of gene expression in mixed bacterial populations and the growth and proliferation of higher plants and lower animals. Here we report that boric acid, the dominant form of boron in plasma, inhibits the proliferation of prostate cancer cell lines, DU-145 and LNCaP, in a dose-dependent manner. Non-tumorigenic prostate cell lines, PWR-1E and RWPE-1, and the cancer line PC-3 were also inhibited, but required concentrations higher than observed human blood levels. Studies using DU-145 cells showed that boric acid induced a cell death-independent proliferative inhibition, with little effect on cell cycle stage distribution and mitochondrial function.

  8. Selection and inhibition mechanisms for human voluntary action decisions

    PubMed Central

    Zhang, Jiaxiang; Hughes, Laura E.; Rowe, James B.

    2012-01-01

    One can choose between action alternatives that have no apparent difference in their outcomes. Such voluntary action decisions are associated with widespread frontal–parietal activation, and a tendency to inhibit the repetition of a previous action. However, the mechanism of initiating voluntary actions and the functions of different brain regions during this process remains largely unknown. Here, we combine computational modeling and functional magnetic resonance imaging to test the selection and inhibition mechanisms that mediate trial-to-trial voluntary action decisions. We fitted an optimized accumulator model to behavioral responses in a finger-tapping task in which participants were instructed to make chosen actions or specified actions. Model parameters derived from each individual were then applied to estimate the expected accumulated metabolic activity (EAA) engaged in every single trial. The EAA was associated with blood oxygenation level-dependent responses in a decision work that was maximal in the supplementary motor area and the caudal anterior cingulate cortex, consistent with a competitive accumulation-to-threshold mechanism for action decision by these regions. Furthermore, specific inhibition of the previous action's accumulator was related to the suppression of response repetition. This action-specific inhibition correlated with the activity of the right inferior frontal gyrus, when the option to repeat existed. Our findings suggest that human voluntary action decisions are mediated by complementary processes of intentional selection and inhibition. PMID:22776456

  9. Selection and inhibition mechanisms for human voluntary action decisions.

    PubMed

    Zhang, Jiaxiang; Hughes, Laura E; Rowe, James B

    2012-10-15

    One can choose between action alternatives that have no apparent difference in their outcomes. Such voluntary action decisions are associated with widespread frontal-parietal activation, and a tendency to inhibit the repetition of a previous action. However, the mechanism of initiating voluntary actions and the functions of different brain regions during this process remains largely unknown. Here, we combine computational modeling and functional magnetic resonance imaging to test the selection and inhibition mechanisms that mediate trial-to-trial voluntary action decisions. We fitted an optimized accumulator model to behavioral responses in a finger-tapping task in which participants were instructed to make chosen actions or specified actions. Model parameters derived from each individual were then applied to estimate the expected accumulated metabolic activity (EAA) engaged in every single trial. The EAA was associated with blood oxygenation level-dependent responses in a decision work that was maximal in the supplementary motor area and the caudal anterior cingulate cortex, consistent with a competitive accumulation-to-threshold mechanism for action decision by these regions. Furthermore, specific inhibition of the previous action's accumulator was related to the suppression of response repetition. This action-specific inhibition correlated with the activity of the right inferior frontal gyrus, when the option to repeat existed. Our findings suggest that human voluntary action decisions are mediated by complementary processes of intentional selection and inhibition. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Pyridinylquinazolines Selectively Inhibit Human Methionine Aminopeptidase-1 in Cells

    PubMed Central

    Zhang, Feiran; Bhat, Shridhar; Gabelli, Sandra B.; Chen, Xiaochun; Miller, Michelle S.; Nacev, Benjamin A.; Cheng, Yim Ling; Meyers, David J.; Tenney, Karen; Shim, Joong Sup; Crews, Phillip; Amzel, L. Mario; Ma, Dawei; Liu, Jun O.

    2013-01-01

    Methionine aminopeptidases (MetAPs) which remove the initiator methionine from nascent peptides are essential in all organisms. While MetAP2 has been demonstrated to be a therapeutic target for inhibiting angiogenesis in mammals, MetAP1 seems to be vital for cell proliferation. Our earlier efforts identified two structural classes of human MetAP1 (HsMetAP1)-selective inhibitors (1–4). But all of them failed to inhibit cellular HsMetAP1. Using Mn(II) or Zn(II) to activate HsMetAP1, we found that 1–4 could only effectively inhibit purified HsMetAP1 in the presence of physiologically unachievable concentrations of Co(II). In an effort to seek Co(II)-independent inhibitors, a novel structural class containing a 2-(pyridin-2-yl)quinazoline core has been discovered. Many compounds in this class potently and selectively inhibited HsMetAP1 without Co(II). Subsequently, we demonstrated that 11j, an auxiliary metal-dependent inhibitor, effectively inhibited HsMetAP1 in primary cells. This is the first report that an HsMetAP1-selective inhibitor is effective against its target in cells. PMID:23634668

  11. Pyridinylquinazolines selectively inhibit human methionine aminopeptidase-1 in cells.

    PubMed

    Zhang, Feiran; Bhat, Shridhar; Gabelli, Sandra B; Chen, Xiaochun; Miller, Michelle S; Nacev, Benjamin A; Cheng, Yim Ling; Meyers, David J; Tenney, Karen; Shim, Joong Sup; Crews, Phillip; Amzel, L Mario; Ma, Dawei; Liu, Jun O

    2013-05-23

    Methionine aminopeptidases (MetAPs), which remove the initiator methionine from nascent peptides, are essential in all organisms. While MetAP2 has been demonstrated to be a therapeutic target for inhibiting angiogenesis in mammals, MetAP1 seems to be vital for cell proliferation. Our earlier efforts identified two structural classes of human MetAP1 (HsMetAP1)-selective inhibitors (1-4), but all of them failed to inhibit cellular HsMetAP1. Using Mn(II) or Zn(II) to activate HsMetAP1, we found that 1-4 could only effectively inhibit purified HsMetAP1 in the presence of physiologically unachievable concentrations of Co(II). In an effort to seek Co(II)-independent inhibitors, a novel structural class containing a 2-(pyridin-2-yl)quinazoline core has been discovered. Many compounds in this class potently and selectively inhibited HsMetAP1 without Co(II). Subsequently, we demonstrated that 11j, an auxiliary metal-dependent inhibitor, effectively inhibited HsMetAP1 in primary cells. This is the first report that an HsMetAP1-selective inhibitor is effective against its target in cells.

  12. Gamma-Glutamylcysteine Inhibits Oxidative Stress in Human Endothelial Cells

    DTIC Science & Technology

    2012-01-01

    γ-Glutamylcysteine inhibits oxidative stress in human endothelial cells Yukiko K. Nakamura a, Michael A. Dubick b, Stanley T. Omaye a,⁎ a Department...n f o Article history: Received 12 July 2011 Accepted 16 October 2011 Keywords: γ-Glutamylcysteine Glutathione Glutathione synthetase Oxidative stress...include reducing risks of oxidative stress-related injuries and diseases. The ob- jective of this studywas to investigate the efficacy of GGC on GSH

  13. Connexin43 Inhibition Prevents Human Vein Grafts Intimal Hyperplasia.

    PubMed

    Longchamp, Alban; Allagnat, Florent; Alonso, Florian; Kuppler, Christopher; Dubuis, Céline; Ozaki, Charles-Keith; Mitchell, James R; Berceli, Scott; Corpataux, Jean-Marc; Déglise, Sébastien; Haefliger, Jacques-Antoine

    2015-01-01

    Venous bypass grafts often fail following arterial implantation due to excessive smooth muscle cells (VSMC) proliferation and consequent intimal hyperplasia (IH). Intercellular communication mediated by Connexins (Cx) regulates differentiation, growth and proliferation in various cell types. Microarray analysis of vein grafts in a model of bilateral rabbit jugular vein graft revealed Cx43 as an early upregulated gene. Additional experiments conducted using an ex-vivo human saphenous veins perfusion system (EVPS) confirmed that Cx43 was rapidly increased in human veins subjected ex-vivo to arterial hemodynamics. Cx43 knock-down by RNA interference, or adenoviral-mediated overexpression, respectively inhibited or stimulated the proliferation of primary human VSMC in vitro. Furthermore, Cx blockade with carbenoxolone or the specific Cx43 inhibitory peptide 43gap26 prevented the burst in myointimal proliferation and IH formation in human saphenous veins. Our data demonstrated that Cx43 controls proliferation and the formation of IH after arterial engraftment.

  14. Connexin43 Inhibition Prevents Human Vein Grafts Intimal Hyperplasia

    PubMed Central

    Longchamp, Alban; Allagnat, Florent; Alonso, Florian; Kuppler, Christopher; Dubuis, Céline; Ozaki, Charles-Keith; Mitchell, James R.; Berceli, Scott; Corpataux, Jean-Marc

    2015-01-01

    Venous bypass grafts often fail following arterial implantation due to excessive smooth muscle cells (VSMC) proliferation and consequent intimal hyperplasia (IH). Intercellular communication mediated by Connexins (Cx) regulates differentiation, growth and proliferation in various cell types. Microarray analysis of vein grafts in a model of bilateral rabbit jugular vein graft revealed Cx43 as an early upregulated gene. Additional experiments conducted using an ex-vivo human saphenous veins perfusion system (EVPS) confirmed that Cx43 was rapidly increased in human veins subjected ex-vivo to arterial hemodynamics. Cx43 knock-down by RNA interference, or adenoviral-mediated overexpression, respectively inhibited or stimulated the proliferation of primary human VSMC in vitro. Furthermore, Cx blockade with carbenoxolone or the specific Cx43 inhibitory peptide 43gap26 prevented the burst in myointimal proliferation and IH formation in human saphenous veins. Our data demonstrated that Cx43 controls proliferation and the formation of IH after arterial engraftment. PMID:26398895

  15. Human erythrocytes inhibit complement-mediated solubilization of immune complexes by human serum

    SciTech Connect

    Dorval, B.L.

    1987-01-01

    The aim of this study was to develop an autologus human system to evaluate the effects of human erythrocytes on solubilization of immune complex precipitates (IC) by human serum. Incubation of IC with fresh human serum or guinea pig serum resulted in solubilization of IC. When packed erythrocytes were added to human serum or guinea pig serum binding of IC to the erythrocyte occurred and IC solubilization was inhibited significantly (p <.025). Sheep erythrocytes did not bind IC or inhibit IC solubilization. To evaluate the role of human erythrocyte complement receptor (CR1) on these findings, human erythrocytes were treated with trypsin or anti-CR1 antibodies. Both treatments abrogated IC binding to human erythrocytes but did not affect the ability of the human erythrocyte to inhibit IC solubilization. Radioimmunoassay was used to measure C3, C4 and C5 activation in human serum after incubation with IC, human erythrocytes, human erythrocytes plus IC, whole blood or in whole blood plus IC.

  16. Human cytomegalovirus function inhibits replication of herpes simplex virus

    SciTech Connect

    Cockley, K.D.; Shiraki, K.; Rapp, F.

    1988-01-01

    Human embryonic lung (HEL) cells infected with human cytomegalovirus (HCMV) restricted the replication of herpes simplex virus type 1 (HSV-1). A delay in HSV replication of 15 h as well as a consistent, almost 3 log inhibition of HSV replication in HCMV-infected cell cultures harvested 24 to 72 h after superinfection were observed compared with controls infected with HSV alone. Treatment of HCMV-infected HEL cells with cycloheximide (100 ..mu..g/ml) for 3 or 24 h was demonstrated effective in blocking HCMV protein synthesis, as shown by immunoprecipitation with HCMV antibody-positive polyvalent serum. Cycloheximide treatment of HCMV-infected HEL cells and removal of the cycloheximide block before superinfection inhibited HSV-1 replication more efficiently than non-drug-treated superinfected controls. HCMV DNA-negative temperature-sensitive mutants restricted HSV as efficiently as wild-type HCMV suggesting that immediate-early and/or early events which occur before viral DNA synthesis are sufficient for inhibition of HSV. Inhibition of HSV-1 in HCMV-infected HEL cells was unaffected by elevated temperature (40.5/sup 0/C). However, prior UV irradiation of HCMV removed the block to HSV replication, demonstrating the requirement for an active HCMV genome. HSV-2 replication was similarly inhibited in HCMV-infected HEL cells. Superinfection of HCMV-infected HEL cells with HSV-1 labeled with (/sup 3/H)thymidine provided evidence that the labeled virus could penetrate to the nucleus of cells after superinfection. Evidence for penetration of superinfecting HSV into HCMV-infected cells was also provided by blot hybridization of HSV DNA synthesized in cells infected with HSV alone versus superinfected cell cultures at 0 and 48 h after superinfection.

  17. Lipid-Lowering Pharmaceutical Clofibrate Inhibits Human Sweet Taste.

    PubMed

    Kochem, Matthew; Breslin, Paul A S

    2017-01-01

    T1R2-T1R3 is a heteromeric receptor that binds sugars, high potency sweeteners, and sweet taste blockers. In rodents, T1R2-T1R3 is largely responsible for transducing sweet taste perception. T1R2-T1R3 is also expressed in non-taste tissues, and a growing body of evidence suggests that it helps regulate glucose and lipid metabolism. It was previously shown that clofibric acid, a blood lipid-lowering drug, binds T1R2-T1R3 and inhibits its activity in vitro The purpose of this study was to determine whether clofibric acid inhibits sweetness perception in humans and is, therefore, a T1R2-T1R3 antagonist in vivo Fourteen participants rated the sweetness intensity of 4 sweeteners (sucrose, sucralose, Na cyclamate, acesulfame K) across a broad range of concentrations. Each sweetener was prepared in solution neat and in mixture with either clofibric acid or lactisole. Clofibric acid inhibited sweetness of every sweetener. Consistent with competitive binding, inhibition by clofibric acid was diminished with increasing sweetener concentration. This study provides in vivo evidence that the lipid-lowering drug clofibric acid inhibits sweetness perception and is, therefore, a T1R carbohydrate receptor inhibitor. Our results are consistent with previous in vitro findings. Given that T1R2-T1R3 may in part regulate glucose and lipid metabolism, future studies should investigate the metabolic effects of T1R inhibition. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Histamine H3 receptor-mediated inhibition of noradrenaline release in the human brain.

    PubMed

    Schlicker, E; Werthwein, S; Zentner, J

    1999-01-01

    Stimulation-evoked 3H-noradrenaline release in human cerebrocortical slices was inhibited by histamine (in a manner sensitive to clobenpropit) and by imetit, suggesting H3 receptor-mediated inhibition of noradrenaline release in human brain.

  19. Inhibition of neutrophil elastase by recombinant human proteinase inhibitor 9.

    PubMed

    Dahlen, J R; Foster, D C; Kisiel, W

    1999-09-21

    Proteinase inhibitor PI9 (PI9) is an intracellular 42-kDa member of the ovalbumin family of serpins that is found primarily in placenta, lung and lymphocytes. PI9 has been shown to be a fast-acting inhibitor of granzyme B in vitro, presumably through the utilization of Glu(340) as the P(1) inhibitory residue in its reactive site loop. In this report, we describe the inhibition of human neutrophil elastase by recombinant human PI9. Inhibition occurred with an overall K(i)' of 221 pM and a second-order association rate constant of 1.5 x 10(5) M(-1) s(-1), indicating that PI9 is a potent inhibitor of this serine proteinase in vitro. In addition, incubation of recombinant PI9 with native neutrophil elastase resulted in the formation of an SDS-resistant 62-kDa complex. Amino-terminal sequence analyses provided evidence that inhibition of elastase occurred through the use of Cys(342) as the reactive P(1) amino acid residue in the PI9 reactive site loop. Thus, PI9 joins its close relatives PI6 and PI8 as having the ability to utilize multiple reactive site loop residues as the inhibitory P(1) residue to expand its inhibitory spectrum.

  20. Somatostatin peptides inhibit basolateral potassium channels in human colonic crypts.

    PubMed

    Sandle, G I; Warhurst, G; Butterfield, I; Higgs, N B; Lomax, R B

    1999-11-01

    Somatostatin is a powerful inhibitor of intestinal Cl(-) secretion. We used patch-clamp recording techniques to investigate the effects of somatostatin on low-conductance (23-pS) K(+) channels in the basolateral membrane of human colonic crypts, which are an important component of the Cl(-) secretory process. Somatostatin (2 microM) elicited a >80% decrease in "spontaneous" K(+) channel activity in cell-attached patches in nonstimulated crypts (50% inhibition = approximately 8 min), which was voltage-independent and was prevented by pretreating crypts for 18 h with pertussis toxin (200 ng/ml), implicating a G protein-dependent mechanism. In crypts stimulated with 100-200 microM dibutyryl cAMP, 2 microM somatostatin and its synthetic analog octreotide (2 microM) both produced similar degrees of K(+) channel inhibition to that seen in nonstimulated crypts, which was also present under low-Cl(-) (5 mM) conditions. In addition, 2 microM somatostatin abolished the increase in K(+) channel activity stimulated by 2 microM thapsigargin but had no effect on the thapsigargin-stimulated rise in intracellular Ca(2+). These results indicate that somatostatin peptides inhibit 23-pS basolateral K(+) channels in human colonic crypt cells via a G protein-dependent mechanism, which may result in loss of the channel's inherent Ca(2+) sensitivity.

  1. Protease activity, localization and inhibition in the human hair follicle.

    PubMed

    Bhogal, R K; Mouser, P E; Higgins, C A; Turner, G A

    2014-02-01

    In humans, the process of hair shedding, referred to as exogen, is believed to occur independently of the other hair cycle phases. Although the actual mechanisms involved in hair shedding are not fully known, it has been hypothesized that the processes leading to the final step of hair shedding may be driven by proteases and/or protease inhibitor activity. In this study, we investigated the presence of proteases and protease activity in naturally shed human hairs and assessed enzyme inhibition activity of test materials. We measured enzyme activity using a fluorescence-based assay and protein localization by indirect immunohistochemistry (IHC). We also developed an ex vivo skin model for measuring the force required to pull hair fibres from skin. Our data demonstrate the presence of protease activity in the tissue material surrounding club roots. We also demonstrated the localization of specific serine protease protein expression in human hair follicle by IHC. These data provide evidence demonstrating the presence of proteases around the hair club roots, which may play a role during exogen. We further tested the hypothesis that a novel protease inhibitor system (combination of Trichogen) and climbazole) could inhibit protease activity in hair fibre club root extracts collected from a range of ethnic groups (U.K., Brazil, China, first-generation Mexicans in the U.S.A., Thailand and Turkey) in both males and females. Furthermore, we demonstrated that this combination is capable of increasing the force required to remove hair in an ex vivo skin model system. These studies indicate the presence of proteolytic activity in the tissue surrounding the human hair club root and show that it is possible to inhibit this activity with a combination of Trichogen and climbazole. This technology may have potential to reduce excessive hair shedding. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  2. Selective inhibition of human acetylcholinesterase by xanthine derivatives: in vitro inhibition and molecular modeling investigations.

    PubMed

    Mohamed, Tarek; Osman, Wesseem; Tin, Gary; Rao, Praveen P N

    2013-08-01

    The commonly used beverage and psychostimulant caffeine is known to inhibit human acetylcholinesterase enzyme. This pharmacological activity of caffeine is partly responsible for its cognition enhancing properties. However, the exact mechanisms of its binding to human cholinesterases (acetyl and butyrylcholinesterase; hAChE and hBuChE) are not well known. In this study, we investigated the cholinesterase inhibition by the xanthine derivatives caffeine, pentoxifylline, and propentofylline. Among them, propentofylline was the most potent AChE inhibitor (hAChE IC₅₀=6.40 μM). The hAChE inhibitory potency was of the order: caffeine (hAChE IC₅₀=7.25 μM)inhibition of hAChE with no inhibition of hBuChE (IC₅₀>50 μM) relative to the reference agent donepezil (hBuChE IC₅₀=13.60 μM). Molecular modeling investigations indicate that caffeine binds primarily in the catalytic site (Ser203, Glu334 and His447) region of hAChE whereas pentoxifylline and propentofylline are able to bind to both the catalytic site and peripheral anionic site due to their increased bulk/size, thereby exhibiting superior AChE inhibition relative to caffeine. In contrast, their lack of hBuChE inhibition is due to a larger binding site and lack of key aromatic amino acids. In summary, our study has important implications in the development of novel caffeine derivatives as selective AChE inhibitors with potential application as cognitive enhancers and to treat various forms of dementia.

  3. Inhibition of human immunodeficiency virus replication by antisense oligodeoxynucleotides.

    PubMed Central

    Goodchild, J; Agrawal, S; Civeira, M P; Sarin, P S; Sun, D; Zamecnik, P C

    1988-01-01

    Twenty different target sites within human immunodeficiency virus (HIV) RNA were selected for studies of inhibition of HIV replication by antisense oligonucleotides. Target sites were selected based on their potential capacity to block recognition functions during viral replication. Antisense oligomers complementary to sites within or near the sequence repeated at the ends of retrovirus RNA (R region) and to certain splice sites were most effective. The effect of antisense oligomer length on inhibiting virus replication was also investigated, and preliminary toxicity studies in mice show that these compounds are toxic only at high levels. The results indicate potential usefulness for these oligomers in the treatment of patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex either alone or in combination with other drugs. PMID:3041414

  4. Inhibition of Human Immunodeficiency Virus Replication by Antisense Oligodeoxynucleotides

    NASA Astrophysics Data System (ADS)

    Goodchild, John; Agrawal, Sudhir; Civeira, Maria P.; Sarin, Prem S.; Sun, Daisy; Zamecnik, Paul C.

    1988-08-01

    Twenty different target sites within human immunodeficiency virus (HIV) RNA were selected for studies of inhibition of HIV replication by antisense oligonucleotides. Target sites were selected based on their potential capacity to block recognition functions during viral replication. Antisense oligomers complementary to sites within or near the sequence repeated at the ends of retrovirus RNA (R region) and to certain splice sites were most effective. The effect of antisense oligomer length on inhibiting virus replication was also investigated, and preliminary toxicity studies in mice show that these compounds are toxic only at high levels. The results indicate potential usefulness for these oligomers in the treatment of patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex either alone or in combination with other drugs.

  5. Conditioned inhibition of autonomic Pavlovian conditioning in humans.

    PubMed

    Neumann, D L; Lipp, O V; Siddle, D A

    1997-10-10

    The present study aimed to demonstrate conditioned inhibition of Pavlovian conditioning of autonomic responses in humans. Subjects (N = 21) were presented initially with four geometric shapes (A, B, C and D). An electric shock served as the unconditioned stimulus (US) during acquisition. Conditional stimuli lasted for 8 s and US onset coincided with CS offset. Subjects were trained with A-US, C-US, and AC-US pairings and AB alone and B alone presentations. The subsequent summation test consisted of C-US pairings and CB alone and CD alone presentations. Conditioning was evident in self-reported US expectancy and first and second interval electrodermal responses. Evidence for conditioned inhibition during the summation test was found in US expectancy and second interval electrodermal responses.

  6. Medial olivocochlear efferent reflex inhibition of human cochlear nerve responses.

    PubMed

    Lichtenhan, J T; Wilson, U S; Hancock, K E; Guinan, J J

    2016-03-01

    Inhibition of cochlear amplifier gain by the medial olivocochlear (MOC) efferent system has several putative roles: aiding listening in noise, protection against damage from acoustic overexposure, and slowing age-induced hearing loss. The human MOC reflex has been studied almost exclusively by measuring changes in otoacoustic emissions. However, to help understand how the MOC system influences what we hear, it is important to have measurements of the MOC effect on the total output of the organ of Corti, i.e., on cochlear nerve responses that couple sounds to the brain. In this work we measured the inhibition produced by the MOC reflex on the amplitude of cochlear nerve compound action potentials (CAPs) in response to moderate level (52-60 dB peSPL) clicks from five, young, normal hearing, awake, alert, human adults. MOC activity was elicited by 65 dB SPL, contralateral broadband noise (CAS). Using tympanic membrane electrodes, approximately 10 h of data collection were needed from each subject to yield reliable measurements of the MOC reflex inhibition on CAP amplitudes from one click level. The CAS produced a 16% reduction of CAP amplitude, equivalent to a 1.98 dB effective attenuation (averaged over five subjects). Based on previous reports of efferent effects as functions of level and frequency, it is possible that much larger effective attenuations would be observed at lower sound levels or with clicks of higher frequency content. For a preliminary comparison, we also measured MOC reflex inhibition of DPOAEs evoked from the same ears with f2's near 4 kHz. The resulting effective attenuations on DPOAEs were, on average, less than half the effective attenuations on CAPs.

  7. The inhibition of human platelet function by ganodermic acids.

    PubMed Central

    Wang, C N; Chen, J C; Shiao, M S; Wang, C T

    1991-01-01

    Human gel-filtered platelets aggregate at greater than 20 microM-ganodermic acid S [lanosta-7,9(11),24-triene-3 beta, 15 alpha-diacetoxy-26-oic acid] [Wang, Chen, Shiao & Wang (1989) Biochim. Biophys. Acta 986, 151-160]. This study showed that platelets at less than 20 microM-ganodermic acid S displayed both concentration- and time-dependent inhibition of function, in which the agent potency in response to inducers was ADP-fibrinogen greater than collagen greater than thrombin. The agent caused a biphasic time-dependent effect on platelet phosphoinositide metabolism. The first phase involved the decrease in the pool size of phosphoinositide by 10-20%. The second phase, in which both the resynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2) and the decrease of [32P]phosphatidic acid occurred, took place after 30 min. Scanning electron microscopy also revealed a time-dependent morphological change in platelets in the presence of the agent. The cells initially became spiculate discs, then swelled to a 'potato-like' morphology at 60 min. Further studies on the time-dependent inhibition of thrombin response revealed that: (1) the percentage inhibition of cell aggregation was comparable with that occurring with an increase of cytosolic free Ca2+ concentration [( Ca2+]i) or the phosphorylation of marker proteins; (2) [32P]Pi-labelled platelets showed the time-dependent inhibition of thrombin-stimulated PIP2 resynthesis as indicated by first-2-min time-course studies of phosphoinositide interconversion; (3) scanning electron microscopy revealed that the aged platelet population showed an increase in the percentage of non-responding cells on prolonged incubation. The results, taken together, enabled one to discuss a possible mechanism for the time-dependent inhibition by ganodermic acid S of platelet response to thrombin. Images Fig. 5. Fig. 6. PMID:1649599

  8. Naloxone inhibits superoxide but not enzyme release by human neutrophils

    SciTech Connect

    Simpkins, C.; Alailima, S.; Tate, E.

    1986-03-01

    The release of toxic oxygen metabolites and enzymes by phagocytic cells is thought to play a role in the multisystemic tissue injury of sepsis. Naloxone protects septic animals. We have found that at concentrations administered to animals (10/sup -7/ to 10/sup -4/M), naloxone inhibited (p < .001) the release of superoxide (O/sub 2//sup -/) by human neutrophils (HN), stimulated with N-formyl methionyl leucyl phenylalanine (FMLP). Naloxone had no effect on cell viability. Maximum inhibition was 65% of the total O/sub 2//sup -/ released (13.1 nMoles/8 min/320,000 cells). FMLP-stimulated release of beta-glucoronidase or lysozyme was not altered by naloxone. Naloxone had no effect on the binding of /sup 3/H FMLP to HN. Using /sup 3/H naloxone and various concentrations of unlabeled naloxone higher affinity (K/sub D/ = 12nM) and lower affinity (K/sub D/ = 4.7 x 10/sup -5/) binding sites were detected. The K/sub D/ of the low affinity site corresponded to the ED/sub 50/ for naloxone inhibition of O/sub 2//sup -/ (1 x 10/sup -5/M). Binding to this low affinity site was decreased by (+) naloxone, beta-endorphin and N acetyl beta-endorphin, but not by leu-enkephalin, thyrotropin releasing factor, prostaglandin D/sub 2/ or E/sub 2/. Conclusions: (1) naloxone inhibits FMLP-stimulated O/sub 2/ but not enzyme release, (2) this inhibition is not due to alteration of FMLP receptor binding, (3) naloxone may act via a low affinity binding site which is ligand specific, and (4) a higher affinity receptor is present on HN.

  9. Low level lead inhibits the human brain cation pump

    SciTech Connect

    Bertoni, J.M.; Sprenkle, P.M. )

    1991-01-01

    The impact of low level lead exposure on human central nervous system function is a major public health concern. This study addresses the inhibition of the cation pump enzyme Na,K-ATPase by low level lead. Human brain tissue was obtained at autopsy and frozen until use. Brain homogenates were preincubated with PbCl{sub 2} for 20 min at 0{degree}C. Inhibition of K-paranitrophenylphosphatase (pNPPase), a measure of the dephosphorylation step of Na,K-ATPase, reached steady state within 10 min. K-pNPPase activity, expressed as a percentage of control, fell to 96.3 {plus minus} 0.9% at 0.25 uM (PbCl{sub 2}) to 82.0 {plus minus} 1.6% at 2.5 uM (PbCl{sub 2}) in homogenates prepared from normal brain. Similar results were obtained with homogenates prepared from brains of patients with a history of alcohol abuse and of those with other miscellaneous conditions. Since the mean blood level of lead in the US has ranged recently from m9.2 to 16.0 ug/dl, these results indicate that current in vivo levels of lead exposure may impair important human brain function.

  10. Platelet inhibition of human lymphocyte PHA-induced blastoid transformation.

    PubMed

    Cress, D C; Metcalf, W K

    1975-01-01

    The reduced PHA responsiveness of human lymphocytes obtained from heparinized as compared to defibrinated blood has been shown to be due to platelet contamination in the former. Inhibition of blastoid transformation and lymphocyte death is directly related to the number of platelets added to a culture. Divalent ions partially reduce this platelet inhibitor phenomenon but do not block if completely. The "toxic" platelet components appear to be localized in the membranes and particulate matter after homogenization and hard centrifugation. Comparative studies of PHA transformation must control platelet contamination of the cultures in order to avoid severe difficulties of interpretation.

  11. Inhibition of human estrogen synthetase (aromatase) by flavones.

    PubMed

    Kellis, J T; Vickery, L E

    1984-09-07

    Several naturally occurring and synthetic flavones were found to inhibit the aromatization of androstenedione and testosterone to estrogens catalyzed by human placental and ovarian microsomes. These flavones include (in order of decreasing potency) 7,8-benzoflavone, chrysin, apigenin, flavone, flavanone, and quercetin; 5,6-benzoflavone was not inhibitory. 7,8-Benzoflavone and chrysin were potent competitive inhibitors and induced spectral changes in the aromatase cytochrome P-450 indicative of substrate displacement. Flavones may thus compete with steroids in their interaction with certain monooxygenases and thereby alter steroid hormone metabolism.

  12. Imeglimin prevents human endothelial cell death by inhibiting mitochondrial permeability transition without inhibiting mitochondrial respiration

    PubMed Central

    Detaille, D; Vial, G; Borel, A-L; Cottet-Rouselle, C; Hallakou-Bozec, S; Bolze, S; Fouqueray, P; Fontaine, E

    2016-01-01

    Imeglimin is the first in a new class of oral glucose-lowering agents, having recently completed its phase 2b trial. As Imeglimin did show a full prevention of β-cell apoptosis, and since angiopathy represents a major complication of diabetes, we studied Imeglimin protective effects on hyperglycemia-induced death of human endothelial cells (HMEC-1). These cells were incubated in several oxidative stress environments (exposure to high glucose and oxidizing agent tert-butylhydroperoxide) which led to mitochondrial permeability transition pore (PTP) opening, cytochrome c release and cell death. These events were fully prevented by Imeglimin treatment. This protective effect on cell death occurred without any effect on oxygen consumption rate, on lactate production and on cytosolic redox or phosphate potentials. Imeglimin also dramatically decreased reactive oxygen species production, inhibiting specifically reverse electron transfer through complex I. We conclude that Imeglimin prevents hyperglycemia-induced cell death in HMEC-1 through inhibition of PTP opening without inhibiting mitochondrial respiration nor affecting cellular energy status. Considering the high prevalence of macrovascular and microvascular complications in type 2 diabetic subjects, these results together suggest a potential benefit of Imeglimin in diabetic angiopathy. PMID:27551496

  13. Human Diversity in a Cell Surface Receptor that Inhibits Autophagy.

    PubMed

    Chaudhary, Anu; Leite, Mara; Kulasekara, Bridget R; Altura, Melissa A; Ogahara, Cassandra; Weiss, Eli; Fu, Wenqing; Blanc, Marie-Pierre; O'Keeffe, Michael; Terhorst, Cox; Akey, Joshua M; Miller, Samuel I

    2016-07-25

    Mutations in genes encoding autophagy proteins have been associated with human autoimmune diseases, suggesting that diversity in autophagy responses could be associated with disease susceptibility or severity. A cellular genome-wide association study (GWAS) screen was performed to explore normal human diversity in responses to rapamycin, a microbial product that induces autophagy. Cells from several human populations demonstrated variability in expression of a cell surface receptor, CD244 (SlamF4, 2B4), that correlated with changes in rapamycin-induced autophagy. High expression of CD244 and receptor activation with its endogenous ligand CD48 inhibited starvation- and rapamycin-induced autophagy by promoting association of CD244 with the autophagy complex proteins Vps34 and Beclin-1. The association of CD244 with this complex reduced Vps34 lipid kinase activity. Lack of CD244 is associated with auto-antibody production in mice, and lower expression of human CD244 has previously been implicated in severity of human rheumatoid arthritis and systemic lupus erythematosus, indicating that increased autophagy as a result of low levels of CD244 may alter disease outcomes.

  14. Response inhibition during perceptual decision making in humans and macaques

    PubMed Central

    Middlebrooks, Paul G.

    2014-01-01

    Response inhibition in stop signal tasks has been explained as the outcome of a race between GO and STOP processes (e.g., Logan, 1981). Response choice in two-alternative perceptual categorization tasks has been explained as the outcome of an accumulation of evidence for the alternative responses. To begin unifying these two powerful investigation frameworks, we obtained data from humans and macaque monkeys performing a stop signal task with responses guided by perceptual categorization and variable degrees of difficulty, ranging from low to high accuracy. Comparable results across species reinforced the validity of this animal model. Response times and errors increased with categorization difficulty. The probability of failing to inhibit responses on stop signal trials increased with stop signal delay, and the response times for failed stop signal trials were shorter than those for trials with no stop signal. Thus, the Logan race model could be applied to estimate the duration of the stopping process. We found that the duration of the STOP process did not vary across a wide range of discrimination accuracies. This is consistent with the functional, and possibly mechanistic, independence of choice and inhibition mechanisms. PMID:24306985

  15. Cannabinoids inhibit cellular respiration of human oral cancer cells.

    PubMed

    Whyte, Donna A; Al-Hammadi, Suleiman; Balhaj, Ghazala; Brown, Oliver M; Penefsky, Harvey S; Souid, Abdul-Kader

    2010-01-01

    The primary cannabinoids, Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and Delta(8)-tetrahydrocannabinol (Delta(8)-THC) are known to disturb the mitochondrial function and possess antitumor activities. These observations prompted us to investigate their effects on the mitochondrial O(2) consumption in human oral cancer cells (Tu183). This epithelial cell line overexpresses bcl-2 and is highly resistant to anticancer drugs. A phosphorescence analyzer that measures the time-dependence of O(2) concentration in cellular or mitochondrial suspensions was used for this purpose. A rapid decline in the rate of respiration was observed when Delta(9)-THC or Delta(8)-THC was added to the cells. The inhibition was concentration-dependent, and Delta(9)-THC was the more potent of the two compounds. Anandamide (an endocannabinoid) was ineffective; suggesting the effects of Delta(9)-THC and Delta(8)-THC were not mediated by the cannabinoidreceptors. Inhibition of O(2) consumption by cyanide confirmed the oxidations occurred in the mitochondrial respiratory chain. Delta(9)-THC inhibited the respiration of isolated mitochondria from beef heart. These results show the cannabinoids are potent inhibitors of Tu183 cellular respiration and are toxic to this highly malignant tumor.

  16. Myostatin inhibits proliferation of human urethral rhabdosphincter satellite cells.

    PubMed

    Akita, Yasuyuki; Sumino, Yasuhiro; Mori, Ken-ichi; Nomura, Takeo; Sato, Fuminori; Mimata, Hiromitsu

    2013-05-01

    Myostatin, a member of the transforming growth factor-β superfamily, is a negative regulator of myogenesis in skeletal muscle. We examined the effect of myostatin and myostatin inhibition by an antagonistic agent, follistatin, on growth of human urethral rhabdosphincter satellite cells (muscle stem cells) to develop a new strategy for treatment of stress urinary incontinence. Rhabdosphincter satellite cells were cultured and selected by magnetic affinity cell sorting using an anti-neural cell adhesion molecule antibody. The cells were transfected with simian virus-40 antigen to extend their lifespan. A cell proliferation assay, a cell cycle analysis and an investigation of signal transduction were carried out. The autocrine action of endogenous myostatin by western blotting, real-time reverse transcription polymerase chain reaction and immunoneutralization using an anti-myostatin antibody was also evaluated. Selectively cultured cells expressed markers of striated muscles and successfully differentiated into myotubes. Myostatin inhibited proliferation of these cells through Smad2 phosphorylation and cell cycle arrest. Inhibitory effects of myostatin were reversed by addition of follistatin. However, rhabdosphincter satellite cells did not appear to use autocrine secretion of myostatin to regulate their proliferation. Inhibition of myostatin function might be a useful pathway in the development of novel strategies for stimulating rhabdosphincter cells regeneration to treat stress urinary incontinence. © 2012 The Japanese Urological Association.

  17. Flavonoid inhibition of aromatase enzyme activity in human preadipocytes.

    PubMed

    Campbell, D R; Kurzer, M S

    1993-09-01

    Eleven flavonoid compounds were compared with aminoglutethimide (AG), a pharmaceutical aromatase inhibitor, for their abilities to inhibit aromatase enzyme activity in a human preadipocyte cell culture system. Flavonoids exerting no effect on aromatase activity were catechin, daidzein, equol, genistein, beta-naphthoflavone (BNF), quercetin and rutin. The synthetic flavonoid, alpha-naphthoflavone (ANF), was the most potent aromatase inhibitor, with an I50 value of 0.5 microM. Three naturally-occurring flavonoids, chrysin, flavone, and genistein 4'-methyl ether (Biochanin A) showed I50 values of 4.6, 68, and 113 microM, respectively, while AG showed an I50 value of 7.4 microM. Kinetic analyses showed that both AG and the flavonoids acted as competitive inhibitors of aromatase. The Ki values, indicating the effectiveness of inhibition, were 0.2, 2.4, 2.4, 22, and 49 microM, for ANF, AG, chrysin, flavone, and Biochanin A, respectively. Chrysin, the most potent of the naturally-occurring flavonoids, was similar in potency and effectiveness to AG, a pharmaceutical aromatase inhibitor used clinically in cases of estrogen-dependent carcinoma. These data suggest that flavonoid inhibition of peripheral aromatase activity may contribute to the observed cancer-preventive hormonal effects of plant-based diets.

  18. The human asparaginase enzyme (ASPG) inhibits growth in leukemic cells

    PubMed Central

    Belviso, Stefania; Amato, Rosario; Perrotti, Nicola; Menniti, Miranda

    2017-01-01

    The human protein ASPG is an enzyme with a putative antitumor activity. We generated in bacteria and then purified a recombinant GST-ASPG protein that we used to characterize the biochemical and cytotoxic properties of the human ASPG. We demonstrated that ASPG possesses asparaginase and PAF acetylhydrolase activities that depend on a critical threonine residue at position 19. Consistently, ASPG but not its T19A mutant showed cytotoxic activity in K562, NALM-6 and MOLT-4 leukemic cell lines but not in normal cells. Regarding the mechanism of action of ASPG, it was able to induce a significant apoptotic death in K562 cells. Taken together our data suggest that ASPG, combining different enzymatic activities, should be considered a promising anti-cancer agent for inhibiting the growth of leukemia cells. PMID:28542249

  19. Monomethylarsonous acid inhibited endogenous cholesterol biosynthesis in human skin fibroblasts

    SciTech Connect

    Guo, Lei; Xiao, Yongsheng; Wang, Yinsheng

    2014-05-15

    Human exposure to arsenic in drinking water is a widespread public health concern, and such exposure is known to be associated with many human diseases. The detailed molecular mechanisms about how arsenic species contribute to the adverse human health effects, however, remain incompletely understood. Monomethylarsonous acid [MMA(III)] is a highly toxic and stable metabolite of inorganic arsenic. To exploit the mechanisms through which MMA(III) exerts its cytotoxic effect, we adopted a quantitative proteomic approach, by coupling stable isotope labeling by amino acids in cell culture (SILAC) with LC-MS/MS analysis, to examine the variation in the entire proteome of GM00637 human skin fibroblasts following acute MMA(III) exposure. Among the ∼ 6500 unique proteins quantified, ∼ 300 displayed significant changes in expression after exposure with 2 μM MMA(III) for 24 h. Subsequent analysis revealed the perturbation of de novo cholesterol biosynthesis, selenoprotein synthesis and Nrf2 pathways evoked by MMA(III) exposure. Particularly, MMA(III) treatment resulted in considerable down-regulation of several enzymes involved in cholesterol biosynthesis. In addition, real-time PCR analysis showed reduced mRNA levels of select genes in this pathway. Furthermore, MMA(III) exposure contributed to a distinct decline in cellular cholesterol content and significant growth inhibition of multiple cell lines, both of which could be restored by supplementation of cholesterol to the culture media. Collectively, the present study demonstrated that the cytotoxicity of MMA(III) may arise, at least in part, from the down-regulation of cholesterol biosynthesis enzymes and the resultant decrease of cellular cholesterol content. - Highlights: • MMA(III)-induced perturbation of the entire proteome of GM00637 cells is studied. • Quantitative proteomic approach revealed alterations of multiple cellular pathways. • MMA(III) inhibits de novo cholesterol biosynthesis. • MMA

  20. Apple juice inhibits human low density lipoprotein oxidation.

    PubMed

    Pearson, D A; Tan, C H; German, J B; Davis, P A; Gershwin, M E

    1999-01-01

    Dietary phenolic compounds, ubiquitous in vegetables and fruits and their juices possess antioxidant activity that may have beneficial effects on human health. The phenolic composition of six commercial apple juices, and of the peel (RP), flesh (RF) and whole fresh Red Delicious apples (RW), was determined by high performance liquid chromatography (HPLC), and total phenols were determined by the Folin-Ciocalteau method. HPLC analysis identified and quantified several classes of phenolic compounds: cinnamates, anthocyanins, flavan-3-ols and flavonols. Phloridzin and hydroxy methyl furfural were also identified. The profile of phenolic compounds varied among the juices. The range of concentrations as a percentage of total phenolic concentration was: hydroxy methyl furfural, 4-30%; phloridzin, 22-36%; cinnamates, 25-36%; anthocyanins, n.d.; flavan-3-ols, 8-27%; flavonols, 2-10%. The phenolic profile of the Red Delicious apple extracts differed from those of the juices. The range of concentrations of phenolic classes in fresh apple extracts was: hydroxy methyl furfural, n.d.; phloridzin, 11-17%; cinnamates, 3-27%; anthocyanins, n.d.-42%; flavan-3-ols, 31-54%; flavonols, 1-10%. The ability of compounds in apple juices and extracts from fresh apple to protect LDL was assessed using an in vitro copper catalyzed human LDL oxidation system. The extent of LDL oxidation was determined as hexanal production using static headspace gas chromatography. The apple juices and extracts, tested at 5 microM gallic acid equivalents (GAE), all inhibited LDL oxidation. The inhibition by the juices ranged from 9 to 34%, and inhibition by RF, RW and RP was 21, 34 and 38%, respectively. Regression analyses revealed no significant correlation between antioxidant activity and either total phenolic concentration or any specific class of phenolics. Although the specific components in the apple juices and extracts that contributed to antioxidant activity have yet to be identified, this study

  1. Bafetinib inhibits functional responses of human eosinophils in vitro.

    PubMed

    Milara, Javier; Martinez-Losa, Maleles; Sanz, Celia; Almudéver, Patricia; Peiró, Teresa; Serrano, Adela; Morcillo, Esteban Jesus; Zaragozá, Cristóbal; Cortijo, Julio

    2013-09-05

    Eosinophils play a prominent role in the process of allergic inflammation. Non-receptor associated Lyn tyrosine kinases generate key initial signals in eosinophils. Bafetinib, a specific Abl/Lyn tyrosine kinase inhibitor has shown a potent antiproliferative activity in leukemic cells, but its effects on eosinophils have not been reported. Therefore, we studied the effects of bafetinib on functional and mechanistic responses of isolated human eosinophils. Bafetinib was more potent than non-specific tyrosin kinase comparators genistein and tyrphostin inhibiting superoxide anion triggered by N-formyl-Met-Leu-Phe (fMLF; 100 nM) (-log IC50=7.25 ± 0.04 M; 6.1 ± 0.04 M; and 6.55 ± 0.03 M, respectively). Bafetinib, genistein and tyrphostin did not modify the [Ca(2+)]i responses to fMLF. Bafetinib inhibited the release of EPO induced by fMLF with higher potency than genistein and tyrphostin (-log IC50=7.24 ± 0.09 M; 5.36 ± 0.28 M; and 5.37 ± 0.19 M, respectively), and nearly suppressed LTC4, ECP and chemotaxis. Bafetinib, genistein and tyrphostin did not change constitutive apoptosis. However bafetinib inhibited the ability of granulocyte-monocyte colony-stimulating factor to prevent apoptosis. The activation of Lyn tyrosine kinase, p-ERK1/2 and p-38 induced by fMLF was suppressed by bafetinib and attenuated by genistein and tyrphostin. In conclusion, bafetinib inhibits oxidative burst and generation of inflammatory mediators, and reverses the eosinophil survival. Therefore, future anti-allergic therapies based on bafetinib, could help to suppress excessive inflammatory response of eosinophils at inflammatory sites.

  2. Acute inhibition of iron bioavailability by zinc: studies in humans.

    PubMed

    Olivares, Manuel; Pizarro, Fernando; Ruz, Manuel; de Romaña, Daniel López

    2012-08-01

    Iron (Fe) and zinc (Zn) deficiencies constitute two of the most important nutritional and public health problems affecting developing countries. Combined supplementation or fortification with Zn and Fe are strategies that can be used to improve the Zn and Fe status of a population. However, there is concern about potential negative interactions between these two micronutrients due to a competitive binding to DMT1 and Zip14 transporter. Studies performed in humans have shown an inhibitory effect of Zn on Fe absorption when both minerals are given together as a solution in fasting conditions. We found that at low doses of iron (0.5 mg) the threshold for the inhibition of iron bioavailability was at a Zn:Fe wt/wt ratio ≥5.9:1, whereas at higher doses of Fe (10 mg) this inhibition occurred at 1:1 Zn:Fe wt/wt ratio. This differential response could be explained by the variation in the abundance of both cations as they compete for a limited number of shared transporters at the enterocyte. Conflicting results have been obtained when this interaction was studied in different food matrices. A negative interaction was not observed when Fe and Zn were provided in a composite hamburger meal, premature formula, human milk, or cow milk. A decrease on Fe absorption was observed in only 1 of 3 studies when Fe and Zn were supplied in wheat flour. The possibility of a negative interaction should be considered for supplementation or fortification programs with both microminerals.

  3. Aliphatic alcohols in spirits inhibit phagocytosis by human monocytes.

    PubMed

    Pál, László; Árnyas, Ervin M; Bujdosó, Orsolya; Baranyi, Gergő; Rácz, Gábor; Ádány, Róza; McKee, Martin; Szűcs, Sándor

    2015-04-01

    A large volume of alcoholic beverages containing aliphatic alcohols is consumed worldwide. Previous studies have confirmed the presence of ethanol-induced immunosuppression in heavy drinkers, thereby increasing susceptibility to infectious diseases. However, the aliphatic alcohols contained in alcoholic beverages might also impair immune cell function, thereby contributing to a further decrease in microbicidal activity. Previous research has shown that aliphatic alcohols inhibit phagocytosis by granulocytes but their effect on human monocytes has not been studied. This is important as they play a crucial role in engulfment and killing of pathogenic microorganisms and a decrease in their phagocytic activity could lead to impaired antimicrobial defence in heavy drinkers. The aim of this study was to measure monocyte phagocytosis following their treatment with those aliphatic alcohols detected in alcoholic beverages. Monocytes were separated from human peripheral blood and phagocytosis of opsonized zymosan particles by monocytes treated with ethanol and aliphatic alcohols individually and in combination was determined. It was shown that these alcohols could suppress the phagocytic activity of monocytes in a concentration-dependent manner and when combined with ethanol, they caused a further decrease in phagocytosis. Due to their additive effects, it is possible that they may inhibit phagocytosis in a clinically meaningful way in alcoholics and episodic heavy drinkers thereby contribute to their increased susceptibility to infectious diseases. However, further research is needed to address this question.

  4. Inhibition of eicosanoid biosynthesis by glucocorticoids in humans.

    PubMed Central

    Sebaldt, R J; Sheller, J R; Oates, J A; Roberts, L J; FitzGerald, G A

    1990-01-01

    Therapeutic doses of glucocorticoids are thought to inhibit prostaglandin and leukotriene formation in humans. Several studies in animals, however, have failed to demonstrate modulation of eicosanoid biosynthesis by steroids in vivo. We administered prednisone (60 mg/day) to eight healthy volunteers and measured eicosanoid formation by a variety of cell types in vivo and ex vivo, using sensitive and specific physicochemical assays. We found that the in vivo course of prednisone failed to inhibit the synthesis of thromboxane A2, prostaglandin I2 (prostacyclin), prostaglandin E2, and leukotriene E4 in vivo and of leukotriene B4 ex vivo. Biosynthesis of leukotriene B4, thromboxane B2, and prostaglandins F2 and E2 by macrophage-rich bronchoalveolar lavage cells was strongly suppressed. These findings indicate that therapeutic regimens of glucocorticoids suppress eicosanoid biosynthesis in human macrophages but not in a number of other cell types with steroid receptors, the capacity for eicosanoid formation, and lipocortin-like material. PMID:2169616

  5. Potentiation and inhibition of migration of human neutrophils by auranofin.

    PubMed Central

    Elferink, J G; de Koster, B M

    1993-01-01

    OBJECTIVES--As auranofin resembles some neutrophil activating sulphur containing compounds, it was decided to investigate whether it had activating effects on neutrophil migration in addition to the published inhibitory effects. METHODS--The Boyden chamber assay was used to determine the migration velocity of human neutrophils. The difference between chemotaxis and chemokinesis was established with a chequerboard assay. RESULTS--Low concentrations of auranofin stimulated human neutrophil migration; concentrations of auranofin higher than 1 mumol/l were inhibitory. Inhibitors of leukotriene formation, or of protein kinase C, had the same effect on auranofin induced potentiation of migration as on fMLP activated migration. Auranofin, at a concentration of 100 nmol/l, caused a transient increase in the cGMP level of neutrophils. The auranofin induced increase in migration was strongly inhibited by methylene blue and by LY83583, two inhibitors of cGMP accumulation. CONCLUSIONS--The auranofin induced enhancement of migration is partly due to a chemokinetic effect, but mainly due to a chemotactic effect. The potentiating effect of auranofin on migration is not specifically due to the ability of the drug to inhibit protein kinase C activity or to generate leukotrienes. These results suggest that the enhancement of neutrophil migration by low levels of auranofin is related to the enhancement of cGMP levels in neutrophils. PMID:8215623

  6. Telmisartan inhibits human urological cancer cell growth through early apoptosis

    PubMed Central

    MATSUYAMA, MASAHIDE; FUNAO, KIYOAKI; KURATSUKURI, KATSUYUKI; TANAKA, TOMOAKI; KAWAHITO, YUTAKA; SANO, HAJIME; CHARGUI, JAMEL; TOURAINE, JEAN-LOUIS; YOSHIMURA, NORIO; YOSHIMURA, RIKIO

    2010-01-01

    Angiotensin II receptor blockers (ARBs) are widely used as hypertensive therapeutic agents. In addition, studies have provided evidence that ARBs have the potential to inhibit the growth of several types of cancer cells. It was reported that telmisartan (a type of ARB) has peroxisome proliferator-activated receptor (PPAR)-γ activation activity. We previously reported that the PPAR-γ ligand induces growth arrest in human urological cancer cells through apoptosis. In this study, we evaluated the effects of telmisartan and other ARBs on cell proliferation in renal cell carcinoma (RCC), bladder cancer (BC), prostate cancer (PC) and testicular cancer (TC) cell lines. The inhibitory effects of telmisartan and other ARBs (candesartan, valsartan, irbesartan and losartan) on the growth of the RCC, BC, PC and TC cell lines was investigated using an MTT assay. Flow cytometry and Hoechst staining were used to determine whether the ARBs induced apoptosis. Telmisartan caused marked growth inhibition in the urological cancer cells in a dose- and time-dependent manner. Urological cancer cells treated with 100 μM telmisartan underwent early apoptosis and DNA fragmentation. However, the other ARBs had no effect on cell proliferation in any of the urological cancer cell lines. Telmisartan may mediate potent anti-proliferative effects in urological cancer cells through PPAR-γ. Thus, telmisartan is a potent target for the prevention and treatment of human urological cancer. PMID:22993542

  7. Sickle erythrocytes inhibit human endothelial cell DNA synthesis

    SciTech Connect

    Weinstein, R.; Zhou, M.A.; Bartlett-Pandite, A.; Wenc, K. )

    1990-11-15

    Patients with sickle cell anemia experience severe vascular occlusive phenomena including acute pain crisis and cerebral infarction. Obstruction occurs at both the microvascular and the arterial level, and the clinical presentation of vascular events is heterogeneous, suggesting a complex etiology. Interaction between sickle erythrocytes and the endothelium may contribute to vascular occlusion due to alteration of endothelial function. To investigate this hypothesis, human vascular endothelial cells were overlaid with sickle or normal erythrocytes and stimulated to synthesize DNA. The erythrocytes were sedimented onto replicate monolayers by centrifugation for 10 minutes at 17 g to insure contact with the endothelial cells. Incorporation of 3H-thymidine into endothelial cell DNA was markedly inhibited during contact with sickle erythrocytes. This inhibitory effect was enhanced more than twofold when autologous sickle plasma was present during endothelial cell labeling. Normal erythrocytes, with or without autologous plasma, had a modest effect on endothelial cell DNA synthesis. When sickle erythrocytes in autologous sickle plasma were applied to endothelial monolayers for 1 minute, 10 minutes, or 1 hour and then removed, subsequent DNA synthesis by the endothelial cells was inhibited by 30% to 40%. Although adherence of sickle erythrocytes to the endothelial monolayers was observed under these experimental conditions, the effect of sickle erythrocytes on endothelial DNA synthesis occurred in the absence of significant adherence. Hence, human endothelial cell DNA synthesis is partially inhibited by contact with sickle erythrocytes. The inhibitory effect of sickle erythrocytes occurs during a brief (1 minute) contact with the endothelial monolayers, and persists for at least 6 hours of 3H-thymidine labeling.

  8. Interleukin-27 Enhances the Potential of Reactive Oxygen Species Generation from Monocyte-derived Macrophages and Dendritic cells by Induction of p47phox

    PubMed Central

    Sowrirajan, Bharatwaj; Saito, Yoshiro; Poudyal, Deepak; Chen, Qian; Sui, Hongyan; DeRavin, Suk See; Imamichi, Hiromi; Sato, Toyotaka; Kuhns, Douglas B.; Noguchi, Noriko; Malech, Harry L.; Lane, H. Clifford; Imamichi, Tomozumi

    2017-01-01

    Interleukin (IL)-27, a member of the IL-12 cytokine family, plays an important and diverse role in the function of the immune system. We have previously demonstrated that IL-27 is an anti-viral cytokine which inhibits HIV-1, HIV-2, Influenza virus and herpes simplex virus infection, and enhances the potential of reactive oxygen species (ROS) generating activity during differentiation of monocytes to macrophages. In this study, we further investigated the mechanism of the enhanced potential for ROS generation by IL-27. Real time PCR, western blot and knock down assays demonstrate that IL-27 is able to enhance the potential of superoxide production not only during differentiation but also in terminally differentiated-macrophages and immature dendritic cells (iDC) in association with the induction of p47phox, a cytosolic component of the ROS producing enzyme, NADPH oxidase, and the increase in amounts of phosphorylated p47phox upon stimulation. We also demonstrate that IL-27 is able to induce extracellular superoxide dismutase during differentiation of monocytes but not in terminal differentiated macrophages. Since ROS plays an important role in a variety of inflammation, our data demonstrate that IL-27 is a potent regulator of ROS induction and may be a novel therapeutic target. PMID:28240310

  9. Heparin inhibits human coronary artery smooth muscle cell migration.

    PubMed

    Kohno, M; Yokokawa, K; Yasunari, K; Minami, M; Kano, H; Mandal, A K; Yoshikawa, J

    1998-09-01

    Heparin, an anticoagulant, has been shown to reduce neointimal proliferation and restenosis following vascular injury in experimental studies, but the clinical trials of heparin in coronary balloon angioplasty have been negative. The current study, therefore, examined the effect of heparin on basal or stimulated migration by serum and platelet-derived growth factor (PDGF)-BB in cultured human coronary artery smooth muscle cells (SMCs) by Boyden's chamber method. In addition, the reversibility of the heparin effect on human coronary artery SMC migration was examined. Fetal calf serum (FCS) and PDGF-BB stimulated SMC migration in a concentration-dependent manner. Heparin in moderate to high concentration (10 to 100 U/mL) exhibited concentration-related inhibition of FCS- and PDGF-BB-stimulated SMC migration; however, a low concentration (1 U/mL) of heparin had no inhibitory effects. Heparin also had weak inhibitory effects on nonstimulated SMC migration. The SMCs that were exposed to a high concentration (100 U/mL) of heparin for 6 hours were capable of migrating after a short lag period of removal of heparin from the culture medium. These SMCs also showed recovery of responses to FCS and PDGF-BB by migrating significantly greater than the nonstimulated level. Furthermore, heparin-containing medium did not contain detached cells. These results indicate that heparin inhibits human coronary artery SMC migration, especially when stimulated by FCS or PDGF-BB, and that this inhibitory effect of heparin is reversible and not simply a function of killing cells.

  10. Luteolin inhibits lipopolysaccharide actions on human gingival fibroblasts.

    PubMed

    Gutiérrez-Venegas, Gloria; Kawasaki-Cárdenas, Perla; Arroyo-Cruz, Santa Rita; Maldonado-Frías, Silvia

    2006-07-10

    Periodontal disease comprises a group of infections that lead to inflammation of the gingiva, periodontal tissue destruction, and in severe cases is accompanied by alveolar bone loss with tooth exfoliation. Actinobacillus actinomycetemcomitans is a Gram-negative microorganism, which possesses and produces lipopolysaccharide (LPS) molecules that play a key role in disease development. Human gingival fibroblasts are the major constituents of gingival connective tissue and may interact directly with bacteria and bacterial products including LPS. Flavonoids possess antioxidant and anti-inflammatory properties that reduce inflammatory molecule expression in macrophages and monocytes. In this study, we evaluated the ability of diverse flavonoids to regulate nitric oxide production of LPS-stimulated human gingival fibroblasts, and studied the effect of luteolin on diminish phosphorylation in mitogen-activated protein kinase (MAPK) family members as well as in protein kinase B (Akt), nuclear factor kappa B (NF-kappaB) activation, inducible nitric oxide synthase (NOS) expression, and nitric oxide (NO) synthesis. We also found that pretreatment with three flavonoids, including quercetin, genistein, and luteolin, blocked nitric oxide synthesis in a dose-dependent fashion. Luteolin exerted the strongest blocking action on expression of this inflammatory mediator. Luteolin pretreatment attenuated LPS-induced extracellular signal-regulated kinase, p38, and Akt phosphorylation. LPS treatment of human gingival fibroblasts resulted in NF-kappaB translocation. Cell pretreatment with luteolin abolished LPS effects on NF-kappaB translocation. In addition, luteolin treatment blocked LPS-induced cellular proliferation inhibition without affecting genetic material integrity. We concluded that luteolin interferes with LPS signaling pathways, reducing activation of several mitogen-activated protein kinase family members, and inhibits inflammatory mediator expression.

  11. Purification, characterization and inhibition of human skin collagenase

    PubMed Central

    Woolley, David E.; Glanville, Robert W.; Roberts, Dennis R.; Evanson, John M.

    1978-01-01

    1. The neutral collagenase released into the culture medium by explants of human skin tissue was purified by ultrafiltration and column chromatography. The final enzyme preparation had a specific activity against thermally reconstituted collagen fibrils of 32μg of collagen degraded/min per mg of enzyme protein, representing a 266-fold increase over that of the culture medium. Electrophoresis in polyacrylamide disc gels showed it to migrate as a single protein band from which enzyme activity could be eluted. Chromatographic and polyacrylamide-gel-elution experiments provided no evidence for the existence of more than one active collagenase. 2. The molecular weight of the enzyme estimated from gel filtration and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis was approx. 60000. The purified collagenase, having a pH optimum of 7.5–8.5, did not hydrolyse the synthetic collagen peptide 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-d-Arg-OH and had no non-specific proteinase activity when examined against non-collagenous proteins. 3. It attacked undenatured collagen in solution at 25°C, producing the two characteristic products TCA(¾) and TCB(¼). Collagen types I, II and III were all cleaved in a similar manner by the enzyme at 25°C, but under similar conditions basement-membrane collagen appeared not to be susceptible to collagenase attack. At 37°C the enzyme attacked gelatin, producing initially three-quarter and one-quarter fragments of the α-chains, which were degraded further at a lower rate. As judged by the release of soluble hydroxyproline peptides and electron microscopy, the purified enzyme degraded insoluble collagen derived from human skin at 37°C, but at a rate much lower than that for reconstituted collagen fibrils. 4. Inhibition of the skin collagenase was obtained with EDTA, 1,10-phenanthroline, cysteine, dithiothreitol and sodium aurothiomaleate. Cartilage proteoglycans did not inhibit the enzyme. The serum proteins α2-macroglobulin

  12. Carbocisteine inhibits rhinovirus infection in human tracheal epithelial cells.

    PubMed

    Yasuda, H; Yamaya, M; Sasaki, T; Inoue, D; Nakayama, K; Yamada, M; Asada, M; Yoshida, M; Suzuki, T; Nishimura, H; Sasaki, H

    2006-07-01

    The aim of the study was to examine the effects of a mucolytic drug, carbocisteine, on rhinovirus (RV) infection in the airways. Human tracheal epithelial cells were infected with a major-group RV, RV14. RV14 infection increased virus titres and the cytokine content of supernatants. Carbocisteine reduced supernatant virus titres, the amount of RV14 RNA in cells, cell susceptibility to RV infection and supernatant cytokine concentrations, including interleukin (IL)-6 and IL-8, after RV14 infection. Carbocisteine reduced the expression of mRNA encoding intercellular adhesion molecule (ICAM)-1, the receptor for the major group of RVs. It also reduced the supernatant concentration of a soluble form of ICAM-1, the number and fluorescence intensity of acidic endosomes in the cells before RV infection, and nuclear factor-kappaB activation by RV14. Carbocisteine also reduced the supernatant virus titres of the minor group RV, RV2, although carbocisteine did not reduce the expression of mRNA encoding a low density lipoprotein receptor, the receptor for RV2. These results suggest that carbocisteine inhibits rhinovirus 2 infection by blocking rhinovirus RNA entry into the endosomes, and inhibits rhinovirus 14 infection by the same mechanism as well as by reducing intercellular adhesion molecule-1 levels. Carbocisteine may modulate airway inflammation by reducing the production of cytokines in rhinovirus infection.

  13. Inhibition of human natural killer (NK) cytotoxicity by Candida albicans

    SciTech Connect

    Zunino, S.; Hudig, D.

    1986-03-01

    Experiments were initiated to determine whether human NK cells are cytotoxic to C. albicans with similar activity observed for mouse NK cells against the yeast Paracoccidiodes brasiliensis. In 48 hour assays using limiting dilutions of C. albicans, strain 3153A, mononuclear leukocytes with NK activity had only marginal effects on yeast outgrowth, whereas granulocytes killed most of the yeast. However, these yeast were able to block NK activity in 4 hr /sup 51/Cr release assays with K562 cells, at yeast to K562 ratios of 10:1 and 100:1. Yeast pretreated with the serum of the majority of donors blocked the NK activity more than untreated yeast. Two of the 7 donors did not enhance NK inhibition after pretreatment of the yeast with their serum. Serum antibody to C. albicans and complement consumption by the yeast correlated with the relative efficiency of NK inhibition for most donors. This report suggests that there may be in vivo interactions between NK cells of the immune system and opportunistic fungal pathogens, which may compromise NK cell function.

  14. Oxidative stress inhibits distant metastasis by human melanoma cells

    PubMed Central

    Piskounova, Elena; Agathocleous, Michalis; Murphy, Malea M.; Hu, Zeping; Huddlestun, Sara E.; Zhao, Zhiyu; Leitch, A. Marilyn; Johnson, Timothy M.; DeBerardinis, Ralph J.; Morrison, Sean J.

    2015-01-01

    Solid cancer cells commonly enter the blood and disseminate systemically but are highly inefficient at forming distant metastases for poorly understood reasons. We studied human melanomas that differed in their metastasis histories in patients and in their capacity to metastasize in NSG mice. All melanomas had high frequencies of cells that formed subcutaneous tumours, but much lower percentages of cells that formed tumours after intravenous or intrasplenic transplantation, particularly among inefficient metastasizers. Melanoma cells in the blood and visceral organs experienced oxidative stress not observed in established subcutaneous tumours. Successfully metastasizing melanomas underwent reversible metabolic changes during metastasis that increased their capacity to withstand oxidative stress, including increased dependence upon NADPH-generating enzymes in the folate pathway. Anti-oxidants promoted distant metastasis in NSG mice. Folate pathway inhibition using low-dose methotrexate, ALDH1L2 knockdown, or MTHFD1 knockdown inhibited distant metastasis without significantly affecting the growth of subcutaneous tumors in the same mice. Oxidative stress thus limits distant metastasis by melanoma cells in vivo. PMID:26466563

  15. Disruption of interleukin-27 signaling results in impaired gamma interferon production but does not significantly affect immunopathology in murine schistosome infection.

    PubMed

    Shainheit, Mara G; Saraceno, Rosita; Bazzone, Lindsey E; Rutitzky, Laura I; Stadecker, Miguel J

    2007-06-01

    In schistosomiasis mansoni, parasite eggs cause hepatointestinal granulomatous inflammation and fibrosis mediated by CD4 T cells specific for egg antigens. The severity of disease varies extensively in humans and among mouse strains. Marked disease exacerbation induced in typically low-pathology C57BL/6 mice by immunization with schistosome egg antigens (SEA) in complete Freund's adjuvant (SEA/CFA) correlates with elevated production of the proinflammatory cytokines gamma interferon (IFN-gamma) and interleukin-17 (IL-17), which are regulated by IL-12 and IL-23, respectively. Here we examined the effect on the schistosome infection of a third member of the IL-12 family of heterodimeric cytokines, IL-27, using SEA/CFA-immunized and unimmunized mice deficient in the IL-27 receptor chain WSX-1 (WSX-1(-/-)). SEA-stimulated bulk mesenteric lymph node cells or CD4 T cells from 7-week-infected WSX-1(-/-) mice produced significantly less IFN-gamma than did those from C57BL/6 mice, even though there was no difference between these mice in exacerbated hepatic egg-induced granulomatous inflammation or in the levels of IL-17 induced by immunization with SEA/CFA. A fraction of the cells in the granulomas stained positive for IL-27, but there were no significant differences between WSX-1(-/-) and BL/6 mice, nor were there differences in the number of CD4 T cells and eosinophils. A 24-week chronic infection resulted in markedly reduced levels of proinflammatory cytokines, including IFN-gamma, in WSX-1(-/-) mice, but again the magnitude of immunopathology was not significantly different between the two groups. These findings indicate that despite the impaired IFN-gamma production, IL-27 signaling has no significant effect on either the magnitude of egg-induced immunopathology or on its closest in vitro correlate, IL-17.

  16. Human serum inhibits adhesion and biofilm formation in Candida albicans

    PubMed Central

    2014-01-01

    Background Candida albicans can form biofilms on intravenous catheters; this process plays a key role in the pathogenesis of catheter infections. This study evaluated the effect of human serum (HS) on C. albicans biofilm formation and the expression of adhesion-related genes in vitro. A C. albicans laboratory strain (ATCC90028) and three clinical strains were grown for 24 h in RPMI 1640 supplemented with HS or RPMI 1640 alone (as a control). The growth of biofilm cells of four strains was monitored by a Live Cell Movie Analyzer, and by XTT reduction assay. The expression of the adhesion-related genes BCR1, ALS1, ALS3, HWP1 and ECE1 was analyzed by RT-PCR at three time points (60 min, 90 min, and 24 h). Results In the adhesion phase, C. albicans cells kept a Brownian movement in RPMI medium containing HS until a large number of germ tubes were formed. In the control group, C. albicans cells quickly adhered to the bottom of the reaction plate. Compared with RPMI 1640, medium supplemented with 3–50% HS caused a significant decrease in biofilm development (all p < 0.001). However, the presence of HS had no significant inhibitory effect on the pre-adhered biofilms (all p > 0.05). Biofilm formation was also inhibited by heat-inactivated and proteinase K pre-treated HS. The presence of 50% HS did not significantly affect the planktonic growth of C. albicans (p > 0.05). At three time points, HS inhibited expression of the ALS1 and ALS3 genes and promoted expression of the HWP1 and ECE1 genes. Significant up-regulation of BCR1 was observed only at the 90-min point. Conclusions Human serum reduces biofilm formation by inhibiting the adhesion of C. albicans cells. This response may be associated with the down-regulation of adhesion-related genes ALS1, ALS3 and BCR1. The inhibitory serum component is protease-resistant and heat stable. PMID:24673895

  17. Reconciling the role of serotonin in behavioral inhibition and aversion: acute tryptophan depletion abolishes punishment-induced inhibition in humans.

    PubMed

    Crockett, Molly J; Clark, Luke; Robbins, Trevor W

    2009-09-23

    The neuromodulator serotonin has been implicated in a large number of affective and executive functions, but its precise contribution to motivation remains unclear. One influential hypothesis has implicated serotonin in aversive processing; another has proposed a more general role for serotonin in behavioral inhibition. Because behavioral inhibition is a prepotent reaction to aversive outcomes, it has been a challenge to reconcile these two accounts. Here, we show that serotonin is critical for punishment-induced inhibition but not overall motor response inhibition or reporting aversive outcomes. We used acute tryptophan depletion to temporarily lower brain serotonin in healthy human volunteers as they completed a novel task designed to obtain separate measures of motor response inhibition, punishment-induced inhibition, and sensitivity to aversive outcomes. After a placebo treatment, participants were slower to respond under punishment conditions compared with reward conditions. Tryptophan depletion abolished this punishment-induced inhibition without affecting overall motor response inhibition or the ability to adjust response bias in line with punishment contingencies. The magnitude of reduction in punishment-induced inhibition depended on the degree to which tryptophan depletion reduced plasma tryptophan levels. These findings extend and clarify previous research on the role of serotonin in aversive processing and behavioral inhibition and fit with current theorizing on the involvement of serotonin in predicting aversive outcomes.

  18. Human platelets inhibit liver fibrosis in severe combined immunodeficiency mice

    PubMed Central

    Takahashi, Kazuhiro; Murata, Soichiro; Fukunaga, Kiyoshi; Ohkohchi, Nobuhiro

    2013-01-01

    concentration of mouse TGF-β in the liver tissue was significantly lower in the hPLT group than in the PBS group (22 ± 5 ng/g liver vs 39 ± 6 ng/g liver, P = 0.02). Phosphorylation of Met was more prevalent in the hPLT group than in the PBS group (37% ± 4%/GAPDH vs 20% ± 8%/GAPDH, P = 0.03). Phosphorylation of SMAD3 was weaker in the hPLT group than in the PBS group (60% ± 12%/GAPDH vs 84% ± 12%/GAPDH, P = 0.1), although this difference was not significant. Furthermore, a lower rate of hepatocyte apoptosis was observed in the hPLT group than in the PBS group (5.9% ± 1.7% vs 2.9% ± 2.1%, P = 0.02). Significant human platelet accumulation was observed in the fibrotic liver tissues, whereas few platelets accumulated in the normal liver. CONCLUSION: Human platelets inhibit liver fibrosis in SCID mice. Increased concentration of HGF in the liver suppresses hepatic stellate cell activation, induces MMPs, and inhibits hepatocyte apoptosis. PMID:23983427

  19. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    PubMed

    Asmis, Lars; Tanner, Felix C; Sudano, Isabella; Lüscher, Thomas F; Camici, Giovanni G

    2010-01-22

    DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysis showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54+/-0.9427%, n=5, P<0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0%+/-4.031, n=9, P=0.0004 versus control) as well as a decreased maximal aggregation (-6.388+/-2.212%, n=6, P=0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents. Copyright 2009 Elsevier Inc. All rights reserved.

  20. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    SciTech Connect

    Asmis, Lars; Tanner, Felix C.; Sudano, Isabella; Luescher, Thomas F.; Camici, Giovanni G.

    2010-01-22

    Background: DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Methods and results: Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysis showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54 {+-} 0.9427%, n = 5, P < 0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0% {+-} 4.031, n = 9, P = 0.0004 versus control) as well as a decreased maximal aggregation (-6.388 {+-} 2.212%, n = 6, P = 0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Conclusions: Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents.

  1. Inhibition of endogenous human dentin MMPs by Gluma

    PubMed Central

    Sabatini, Camila; Scheffel, Débora L.S.; Scheffel, Régis H.; Agee, Kelli A.; Rouch, Katelyn; Takahashi, Masahiro; Breschi, Lorenzo; Mazzoni, Annalisa; Tjäderhane, Leo; Tay, Franklin R.; Pashley, David H.

    2014-01-01

    Objective The objective of this study was to determine if Gluma dentin desensitizer (5.0% glutaraldehyde and 35% HEMA in water) can inhibit the endogenous MMPs of dentin matrices in 60 sec. and to evaluate its effect on dentin matrix stiffness and dry mass weight. Methods Dentin beams of 2×1×6 mm were obtained from extracted human third molars coronal dentin. To measure the influence of Gluma treatment time on total MMP activity of dentin, beams were dipped in 37% phosphoric acid (PA) for 15 sec. and rinsed in water. The acid-etched beams were then dipped in Gluma for 5, 15, 30 or 60 sec., rinsed in water and incubated into SensoLyte generic MMP substrate (AnaSpec, Inc.) for 60 min. Controls were dipped in water for 60 sec. Additional beams of 1×1×6 mm were completely demineralized in 37% PA for 18 h, rinsed and used to evaluate changes on the dry weight and modulus of elasticity (E) after 60 sec. of Gluma treatment followed by incubation in simulated body fluid buffer for zero, one or four weeks. E was measured by 3-pt flexure. Results Gluma treatment inhibited total MMP activity of acid-etched dentin by 44, 50, 84, 86 % after 5, 15, 30 or 60 sec. of exposure, respectively. All completely demineralized dentin beams lost stiffness after one and four weeks, with no significant differences between the control and Gluma-treated dentin. Gluma treatment for 60 sec. yielded significantly less dry mass loss than the control after four weeks. Significance The use of Gluma may contribute to the preservation of adhesive interfaces by its cross-linking and inhibitory properties of endogenous dentin MMPs. PMID:24846803

  2. Metabolism and Metabolic Inhibition of Xanthotoxol in Human Liver Microsomes

    PubMed Central

    Shi, Xianbao; Zhang, Gang; Guo, Feng

    2016-01-01

    Cytochrome p450 (CYP450) enzymes are predominantly involved in Phase I metabolism of xenobiotics. In this study, the CYP450 isoforms involved in xanthotoxol metabolism were identified using recombinant CYP450s. In addition, the inhibitory effects of xanthotoxol on eight CYP450 isoforms and its pharmacokinetic parameters were determined using human liver microsomes. CYP1A2, one of CYP450s, played a key role in the metabolism of xanthotoxol compared to other CYP450s. Xanthotoxol showed stronger inhibition on CYP3A4 and CYP1A2 compared to other isoenzymes with the IC50 of 7.43 μM for CYP3A4 and 27.82 μM for CYP1A2. The values of inhibition kinetic parameters (Ki) were 21.15 μM and 2.22 μM for CYP1A2 and CYP3A4, respectively. The metabolism of xanthotoxol obeyed the typical monophasic Michaelis-Menten kinetics and Vmax, Km, and CLint values were calculated as 0.55 nmol·min−1·mg−1, 8.46 μM, and 0.06 mL·min−1·mg−1. In addition, the results of molecular docking showed that xanthotoxol was bound to CYP1A2 with hydrophobic and π-π bond and CYP3A4 with hydrogen and hydrophobic bond. We predicted the hepatic clearance (CLH) and the CLH value was 15.91 mL·min−1·kg−1 body weight. These data were significant for the application of xanthotoxol and xanthotoxol-containing herbs. PMID:27034690

  3. Mitraphylline inhibits lipopolysaccharide-mediated activation of primary human neutrophils.

    PubMed

    Montserrat-de la Paz, Sergio; Fernandez-Arche, Angeles; de la Puerta, Rocío; Quilez, Ana M; Muriana, Francisco J G; Garcia-Gimenez, Maria Dolores; Bermudez, Beatriz

    2016-02-15

    Mitraphylline (MTP) is the major pentacyclic oxindolic alkaloid presented in Uncaria tomentosa. It has traditionally been used to treat disorders including arthritis, heart disease, cancer, and other inflammatory diseases. However, the specific role of MTP is still not clear, with more comprehensivestudies, our understanding of this ancient herbal medicine will continue growing. Some studies provided its ability to inhibit proinflamatory cytokines, such as TNF-α, through NF-κB-dependent mechanism. TNF-α primes neutrophils and modulates phagocytic and oxidative burst activities in inflammatory processes. Since, neutrophils represent the most abundant pool of leukocytes in human blood and play a crucial role in inflammation, we aimed to determine the ability of MTP to modulate neutrophil activation and differentially regulate inflammatory-related cytokines. To determine the mechanism of action of MTP, we investigated the effects on LPS-activated human primary neutrophils responses including activation surface markers by FACS and the expression of inflammatory cytokines, measured by real time PCR and ELISA. Treatment with MTP reduced the LPS-dependent activation effects. Activated neutrophils (CD16(+)CD62L(-)) diminished after MTP administration. Moreover, proinflamatory cytokines (TNF-α, IL-6 or IL-8) expression and secretion were concomitantly reduced, similar to basal control conditions. Taken together, our results demonstrate that MTP is able to elicit an anti-inflammatory response that modulates neutrophil activation contributing to the attenuation of inflammatory episodes. Further studies are need to characterize the mechanism by which MTP can affect this pathway that could provide a means to develop MTP as new candidate for inflammatory disease therapies. Copyright © 2016 Elsevier GmbH. All rights reserved.

  4. Triiodothyronine inhibits transcription from the human growth hormone promoter.

    PubMed

    Morin, A; Louette, J; Voz, M L; Tixier-Vidal, A; Belayew, A; Martial, J A

    1990-07-09

    Three DNA constructs, the natural human growth hormone gene (hGH-hGH) its 500 bp promoter linked to the chloramphenicol acetyl transferase reporter gene (hGH-CAT), and its structural part linked to the herpes virus thymidine kinase promoter (TK-hGH) were introduced into rat pituitary GC cells by DEAE-dextran transfection. Transient expression was followed as a function of triiodothyronine (T3) concentration. The hGH-CAT expression was specifically inhibited by T3 following a typical dose-response curve while hGH-GH gene expression was not significantly modified. The transient expression of TK-hGH increased as a function of T3 concentration. These results indicate that T3 exerts two opposite effects on hGH gene expression. First, it down-regulates expression by acting on the promoter; second, it up-regulates expression by acting on the structural part of the gene. These action could be due to regulation of transcription and mRNA stabilization, respectively.

  5. Troponin I is present in human cartilage and inhibits angiogenesis

    PubMed Central

    Moses, Marsha A.; Wiederschain, Dmitri; Wu, Inmin; Fernandez, Cecilia A.; Ghazizadeh, Vahid; Lane, William S.; Flynn, Evelyn; Sytkowski, Arthur; Tao, Terence; Langer, Robert

    1999-01-01

    Cartilage is an avascular and relatively tumor-resistant tissue. Work from a number of laboratories, including our own, has demonstrated that cartilage is an enriched source of endogenous inhibitors of angiogenesis. In the course of a study designed to identify novel cartilage-derived inhibitors of new capillary growth, we have purified an inhibitory protein that was identified by peptide microsequencing and protein database analysis as troponin I (TnI). TnI is a subunit of the troponin complex (troponin-C and troponin-T being the other two), which, along with tropomyosin, is responsible for the calcium-dependent regulation of striated muscle contraction; independently, TnI is capable of inhibiting actomyosin ATPase. Because troponin has never previously been reported to be present in cartilage, we have cloned and expressed the cDNA of human cartilage TnI, purified this protein to apparent homogeneity, and demonstrated that it is a potent and specific inhibitor of angiogenesis in vivo and in vitro, as well as of tumor metastasis in vivo. PMID:10077564

  6. Trypanosoma cruzi: Inhibition of infection of human monocytes by aspirin.

    PubMed

    Carvalho de Freitas, Rafael; Lonien, Sandra Cristina Heim; Malvezi, Aparecida Donizette; Silveira, Guilherme Ferreira; Wowk, Pryscilla Fanini; da Silva, Rosiane Valeriano; Yamauchi, Lucy Megumi; Yamada-Ogatta, Sueli Fumie; Rizzo, Luiz Vicente; Bordignon, Juliano; Pinge-Filho, Phileno

    2017-09-19

    Cell invasion by Trypanosoma cruzi and its intracellular replication are essential for progression of the parasite life cycle and development of Chagas disease. Prostaglandin E2 (PGE2) and other eicosanoids potently modulate host response and contribute to Chagas disease progression. In this study, we evaluated the effect of aspirin (ASA), a non-selective cyclooxygenase (COX) inhibitor on the T. cruzi invasion and its influence on nitric oxide and cytokine production in human monocytes. The pretreatment of monocytes with ASA or SQ 22536 (adenylate-cyclase inhibitor) induced a marked inhibition of T. cruzi infection. On the other hand, the treatment of monocytes with SQ 22536 after ASA restored the invasiveness of T. cruzi. This reestablishment was associated with a decrease in nitric oxide and PGE2 production, and also an increase of interleukin-10 and interleukin-12 by cells pre-treated with ASA. Altogether, these results reinforce the idea that the cyclooxygenase pathway plays a fundamental role in the process of parasite invasion in an in vitro model of T. cruzi infection. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Dicinnamoylquinides in roasted coffee inhibit the human adenosine transporter.

    PubMed

    de Paulis, Tomas; Schmidt, Dennis E; Bruchey, Aleksandra K; Kirby, Michael T; McDonald, Michael P; Commers, Patricia; Lovinger, David M; Martin, Peter R

    2002-05-10

    Preliminary screening of a minor, non-xanthine constituent of roasted coffee, 3,4-diferuloyl-1,5-quinolactone (DIFEQ), showed inhibition of the adenosine transporter at low micromolar concentration. DIFEQ is a neutral derivative of the chlorogenic acids, i.e. isomeric mono- and di-substituted coumaroyl-, caffeoyl-, and feruloyl-esters of quinic acid, formed in the roasting process of coffee. Displacement of the adenosine transporter antagonist [(3)H](S)-(nitrobenzyl)-6-thioinosine binding by DIFEQ in cultured U-937 cell preparations, expressing the human adenosine transporter protein (hENT1), showed a K(i) of 0.96+/-0.13 microM. Extracts of regular and decaffeinated coffee showed binding activities equivalent to 30-40 mg DIFEQ per three cups of coffee. Acute administration of a high dose of DIFEQ (100 mg/kg i.p.) reduced open field locomotion in mice for 20 min in correlation with brain levels of DIFEQ. Both 3,4-dicaffeoyl-1,5-quinide and 3,4-dicoumaroyl-1,5-quinide, two close structural analogs of DIFEQ also present in roasted coffee, showed similar affinities for the adenosine transporter, while the corresponding 3- and 4-mono caffeoyl- and feruloyl-quinides were one to two orders of magnitudes less active. This suggests that 3,4-dicinnamoyl-1,5-quinides in coffee could have the potential to raise extra-cellular adenosine levels, thereby counteracting the stimulant effect of caffeine.

  8. Tiliroside and gnaphaliin inhibit human low density lipoprotein oxidation.

    PubMed

    Schinella, Guillermo R; Tournier, Horacio A; Máñez, Salvador; de Buschiazzo, Perla M; Del Carmen Recio, María; Ríos, José Luis

    2007-01-01

    Two flavonoids, gnaphaliin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their capacity to inhibit Cu(2+)-induced human low density lipoprotein (LDL) and diluted plasma oxidation. LDL oxidation was monitored by conjugated diene, thiobarbituric acid-reactive substances (TBARS) formation and electrophoretic mobility on agarose gel. Gnaphaliin and tiliroside increased the lag-phase for diene conjugate production in a dose-dependent manner. The reduction of TBARS production confirmed the antioxidant activity of gnaphaliin and tiliroside with 50% inhibitory concentration (IC(50)) values of 8.0+/-3.9 microM and 7.0+/-2.6 microM respectively. Furthermore, the flavonoids negated the Cu(2+)-induced increase in electrophoretic mobility of LDL. Antioxidant activity of gnaphaliin and tiliroside was significantly different when diluted plasma was oxidised by adding 1 mM CuSO(4). Although both flavonoids again reduced the TBARS production, tiliroside showed higher activity than gnaphaliin (IC(50)=10.6+/-2.5 microM vs. IC(50)>50 microM). In conclusion, tiliroside and gnaphaliin are antioxidants against in vitro Cu(2+)-induced LDL oxidation in the same order of magnitude compared to that of the reference drug, probucol.

  9. Enterobacter cloacae inhibits human norovirus infectivity in gnotobiotic pigs.

    PubMed

    Lei, Shaohua; Samuel, Helen; Twitchell, Erica; Bui, Tammy; Ramesh, Ashwin; Wen, Ke; Weiss, Mariah; Li, Guohua; Yang, Xingdong; Jiang, Xi; Yuan, Lijuan

    2016-04-26

    Human noroviruses (HuNoVs) are the leading cause of epidemic gastroenteritis worldwide. Study of HuNoV biology has been hampered by the lack of an efficient cell culture system. Recently, enteric commensal bacteria Enterobacter cloacae has been recognized as a helper in HuNoV infection of B cells in vitro. To test the influences of E. cloacae on HuNoV infectivity and to determine whether HuNoV infects B cells in vivo, we colonized gnotobiotic pigs with E. cloacae and inoculated pigs with 2.74 × 10(4) genome copies of HuNoV. Compared to control pigs, reduced HuNoV shedding was observed in E. cloacae colonized pigs, characterized by significantly shorter duration of shedding in post-inoculation day 10 subgroup and lower cumulative shedding and peak shedding in individual pigs. Colonization of E. cloacae also reduced HuNoV titers in intestinal tissues and in blood. In both control and E. cloacae colonized pigs, HuNoV infection of enterocytes was confirmed, however infection of B cells was not observed in ileum, and the entire lamina propria in sections of duodenum, jejunum, and ileum were HuNoV-negative. In summary, E. cloacae inhibited HuNoV infectivity, and B cells were not a target cell type for HuNoV in gnotobiotic pigs, with or without E. cloacae colonization.

  10. Human milk oligosaccharides inhibit growth of group B Streptococcus.

    PubMed

    Lin, Ann E; Autran, Chloe A; Szyszka, Alexandra; Escajadillo, Tamara; Huang, Mia; Godula, Kamil; Prudden, Anthony R; Boons, Geert-Jan; Lewis, Amanda L; Doran, Kelly S; Nizet, Victor; Bode, Lars

    2017-07-07

    Streptococcus agalactiae (group B Streptococcus, GBS) is a leading cause of invasive bacterial infections in newborns, typically acquired vertically during childbirth secondary to maternal vaginal colonization. Human milk oligosaccharides (HMOs) have important nutritional and biological activities that guide the development of the immune system of the infant and shape the composition of normal gut microbiota. In this manner, HMOs help protect against pathogen colonization and reduce the risk of infection. In the course of our studies of HMO-microbial interactions, we unexpectedly uncovered a novel HMO property to directly inhibit the growth of GBS independent of host immunity. By separating different HMO fractions through multidimensional chromatography, we found the bacteriostatic activity to be confined to specific non-sialylated HMOs and synergistic with a number of conventional antibiotic agents. Phenotypic screening of a GBS transposon insertion library identified a mutation within a GBS-specific gene encoding a putative glycosyltransferase that confers resistance to HMOs, suggesting that HMOs may function as an alternative substrate to modify a GBS component in a manner that impairs growth kinetics. Our study uncovers a unique antibacterial role for HMOs against a leading neonatal pathogen and expands the potential therapeutic utility of these versatile molecules. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Downregulation of CCR1 inhibits human hepatocellular carcinoma cell invasion

    SciTech Connect

    Wu Xiaofeng; Fan Jia; E-mail: jiafan99@yahoo.com; Wang Xiaoying; Zhou Jian; Qiu Shuangjian; Yu Yao; Liu Yinkun; Tang Zhaoyou

    2007-04-20

    CC chemokine receptor 1 (CCR1) has an important role in the recruitment of leukocytes to the site of inflammation. The migration and metastasis of tumor cells shares many similarities with leukocyte trafficking, which is mainly regulated by chemokine receptor-ligand interactions. CCR1 is highly expressed in hepatocellular carcinoma (HCC) cells and tissues with unknown functions. In this study, we silenced CCR1 expression in the human HCC cell line HCCLM3 using artificial microRNA (miRNA)-mediated RNA interference (RNAi) and examined the invasiveness and proliferation of CCR1-silenced HCCLM3 cells and the matrix metalloproteinase (MMP) activity. The miRNA-mediated knockdown expression of CCR1 significantly inhibited the invasive ability of HCCLM3 cells, but had only a minor effect on the cellular proliferation rate. Moreover, CCR1 knockdown significantly reduced the secretion of MMP-2. Together, these findings indicate that CCR1 has an important role in HCCLM3 invasion and that CCR1 might be a new target of HCC treatment.

  12. Enterobacter cloacae inhibits human norovirus infectivity in gnotobiotic pigs

    PubMed Central

    Lei, Shaohua; Samuel, Helen; Twitchell, Erica; Bui, Tammy; Ramesh, Ashwin; Wen, Ke; Weiss, Mariah; Li, Guohua; Yang, Xingdong; Jiang, Xi; Yuan, Lijuan

    2016-01-01

    Human noroviruses (HuNoVs) are the leading cause of epidemic gastroenteritis worldwide. Study of HuNoV biology has been hampered by the lack of an efficient cell culture system. Recently, enteric commensal bacteria Enterobacter cloacae has been recognized as a helper in HuNoV infection of B cells in vitro. To test the influences of E. cloacae on HuNoV infectivity and to determine whether HuNoV infects B cells in vivo, we colonized gnotobiotic pigs with E. cloacae and inoculated pigs with 2.74 × 104 genome copies of HuNoV. Compared to control pigs, reduced HuNoV shedding was observed in E. cloacae colonized pigs, characterized by significantly shorter duration of shedding in post-inoculation day 10 subgroup and lower cumulative shedding and peak shedding in individual pigs. Colonization of E. cloacae also reduced HuNoV titers in intestinal tissues and in blood. In both control and E. cloacae colonized pigs, HuNoV infection of enterocytes was confirmed, however infection of B cells was not observed in ileum, and the entire lamina propria in sections of duodenum, jejunum, and ileum were HuNoV-negative. In summary, E. cloacae inhibited HuNoV infectivity, and B cells were not a target cell type for HuNoV in gnotobiotic pigs, with or without E. cloacae colonization. PMID:27113278

  13. Human milk mucin 1 and mucin 4 inhibit Salmonella enterica serovar Typhimurium invasion of human intestinal epithelial cells in vitro.

    PubMed

    Liu, Bo; Yu, Zhuoteng; Chen, Ceng; Kling, David E; Newburg, David S

    2012-08-01

    Many human milk glycans inhibit pathogen binding to host receptors and their consumption by infants is associated with reduced risk of disease. Salmonella infection is more frequent among infants than among the general population, but the incidence is lower in breast-fed babies, suggesting that human milk could contain components that inhibit Salmonella. This study aimed to test whether human milk per se inhibits Salmonella invasion of human intestinal epithelial cells in vitro and, if so, to identify the milk components responsible for inhibition. Salmonella enterica serovar Typhimurium SL1344 (SL1344) invasion of FHs 74 Int and Caco-2 cells were the models of human intestinal epithelium infection. Internalization of fluorescein-5-isothiocyanate-labeled SL1344 into intestinal cells was measured by flow cytometry to quantify infection. Human milk and its fractions inhibited infection; the inhibitory activity localized to the high molecular weight glycans. Mucin 1 and mucin 4 were isolated to homogeneity. At 150 μg/L, a typical concentration in milk, human milk mucin 1 and mucin 4 inhibited SL1344 invasion of both target cell types. These mucins inhibited SL1344 invasion of epithelial cells in a dose-dependent manner. Thus, mucins may prove useful as a basis for developing novel oral prophylactic and therapeutic agents that inhibit infant diseases caused by Salmonella and related pathogens.

  14. Inhibition of human lysosomal elastase by the cartilage bone marrow extract Rumalon.

    PubMed

    Baici, A; Salgam, P; Fehr, K; Böni, A

    1981-01-01

    Human lysosomal elastase from polymorphonuclear leucocytes is inhibited by the cartilage bone marrow extract Rumalon. Separately, both the cartilage and the bone marrow extracts are able to inhibit the enzymatic activity by 73%, under saturating conditions. The mixture of the two extracts inhibits elastase by 93%. It is suggested that the two partners act as a cumulative inhibition mechanism and this phenomenon is emphasized in a general theoretical model for synergy of proteinase-directed inhibitors.

  15. Exogenous nitric oxide inhibits sympathetically mediated vasoconstriction in human skin

    PubMed Central

    Durand, S; Davis, SL; Cui, J; Crandall, CG

    2005-01-01

    Two experiments were performed to identify whether nitric oxide (NO) inhibits sympathetically mediated vasoconstriction in human skin. In eight subjects increasing doses of sodium nitroprusside (SNP; 8.4 × 10−6–8.4 × 10−3 m) were administered via intradermal microdialysis. At each dose of SNP, cutaneous vasoconstrictor responsiveness was assessed during a 3 min whole-body cold stress. The relative reduction in forearm cutaneous vascular conductance (CVC) during the cold stress was significantly attenuated for SNP doses greater than 8.4 × 10−4 m (control: 63.0 ± 4.1%, SNP 8.4 × 10−6 m: 57.1 ± 4.7%, SNP 8.4 × 10−5 m: 57.0 ± 3.6%, SNP 8.4 × 10−4m: 44.5 ± 5.4% and SNP 8.4 × 10−3m: 28.8 ± 7.9%). The second experiment was performed to identify whether this response was due to NO attenuating sympathetically mediated vasoconstriction or due to a non-specific effect of an elevated CVC secondary to SNP administration. In seven subjects forearm CVC during a whole-body cold stress was assessed at two sites: at a site dilated via microdialysis administration of SNP and at a site dilated with isoproterenol (ISO). CVC was not different between sites prior to (SNP: 0.42 ± 0.11; ISO: 0.46 ± 0.11 AU mmHg−1 (AU, arbitrary units), P > 0.05) or following drug infusion (SNP: 1.36 ± 0.21; ISO: 1.27 ± 0.23 AU mmHg−1, P > 0.05). The reduction in CVC during the subsequent cold stress was significantly less at the SNP site (38.1 ± 6.2%) relative to the ISO site (65.0 ± 5.5%; P = 0.007). These data suggest NO is capable of inhibiting sympathetically mediated vasoconstriction in the cutaneous vasculature. PMID:15539401

  16. Protease activity, localization and inhibition in the human hair follicle

    PubMed Central

    Bhogal, R K; Mouser, P E; Higgins, C A; Turner, G A

    2014-01-01

    Synopsis Objective In humans, the process of hair shedding, referred to as exogen, is believed to occur independently of the other hair cycle phases. Although the actual mechanisms involved in hair shedding are not fully known, it has been hypothesized that the processes leading to the final step of hair shedding may be driven by proteases and/or protease inhibitor activity. In this study, we investigated the presence of proteases and protease activity in naturally shed human hairs and assessed enzyme inhibition activity of test materials. Methods We measured enzyme activity using a fluorescence-based assay and protein localization by indirect immunohistochemistry (IHC). We also developed an ex vivo skin model for measuring the force required to pull hair fibres from skin. Results Our data demonstrate the presence of protease activity in the tissue material surrounding club roots. We also demonstrated the localization of specific serine protease protein expression in human hair follicle by IHC. These data provide evidence demonstrating the presence of proteases around the hair club roots, which may play a role during exogen. We further tested the hypothesis that a novel protease inhibitor system (combination of Trichogen® and climbazole) could inhibit protease activity in hair fibre club root extracts collected from a range of ethnic groups (UK, Brazil, China, first-generation Mexicans in the USA, Thailand and Turkey) in both males and females. Furthermore, we demonstrated that this combination is capable of increasing the force required to remove hair in an ex vivo skin model system. Conclusion These studies indicate the presence of proteolytic activity in the tissue surrounding the human hair club root and show that it is possible to inhibit this activity with a combination of Trichogen® and climbazole. This technology may have potential to reduce excessive hair shedding. Résumé Objectif Chez l'homme, le processus de perte de cheveux, désigné comme exog

  17. Deguelin inhibits human hepatocellular carcinoma by antiangiogenesis and apoptosis.

    PubMed

    Lee, Ju-Hee; Lee, Don-Haeng; Lee, Hyun-Seung; Choi, Joon-Seok; Kim, Kyu-Won; Hong, Soon-Sun

    2008-07-01

    Deguelin is a rotenoid isolated from several plant species, which has been reported to have chemopreventive effects in skin, mammary, colon and lung cancers. The effects of deguelin on the proliferation and apoptosis of hepatic cancer cells were assessed by MTT assay and flow cytometric analysis. The growth of hepatic cancer cells (HepG2, Huh7 and SK-Hep1) was inhibited by deguelin in a dose-dependent manner. HepG2 cells of all the cell lines were the most sensitive to deguelin (IC50 = 0.62 microM). The proportion of sub-G1 apoptotic cells increased from 5.19 to 41.27% by deguelin (0.01-10 microM) treatment for 3 days in the HepG2 cells. The effects of deguelin on anti-angiogenesis of the HepG2 cells were assessed by using Western blot and RT-PCR analysis. Treatment of HepG2 cells with deguelin for 16 h under hypoxia conditions reduced the expression of the hypoxia-inducible factor 1alpha protein and vascular endothelial growth factor mRNA in a dose-dependent manner. In order to investigate whether deguelin shows antiangiogenic activities, we performed in vitro and in vivo angiogenesis assays. In a tube formation assay, deguelin remarkably reduced the capillary network formation of human umbilical vein endothelial cells (HUVECs) on Matrigel beds. Furthermore, deguelin markedly decreased the migration of HUVECs compared to the control and reduced angiogenesis on the CAM of chick embryos. These results suggest that deguelin is potentially useful as a chemotherapeutic agent in hepatocellular carcinoma.

  18. Inhibition of human natural killer cell functional activity by human aspartyl β-hydroxylase.

    PubMed

    Huyan, Ting; Li, Qi; Ye, Lin-Jie; Yang, Hui; Xue, Xiao-Ping; Zhang, Ming-Jie; Huang, Qing-Sheng; Yin, Da-Chuan; Shang, Peng

    2014-12-01

    Natural killer (NK) cells are a key component of the innate immune system and play pivotal roles as inflammatory regulators and in tumor surveillance. Human aspartyl β-hydroxylase (HAAH) is a plasma membrane and endoplasmic reticulum protein with hydroxylation activity, which is over-expressed in many malignant neoplasms and can be detected from the sera of tumor patients. HAAH is involved in regulating tumor cell infiltration and metastasis. Escaping from immune surveillance may help tumor cell infiltration and metastasis. However, the effects of HAAH on tumor immune surveillance have not yet been investigated carefully. The present study investigated the potential use of HAAH as an immune regulator of human NK cells. We assessed the effects of recombinant HAAH (r-HAAH) on primary human NK cell morphology, viability, cytotoxicity, apoptosis, receptors expression and cytokine/cytolytic proteins production. Our results demonstrated that r-HAAH negatively affects NK cell activity in a time and dose-dependent manner. It noticeably reduces the viability of the NK cells by increasing apoptosis and necrosis via caspase signaling pathways. Moreover, r-HAAH reduces the NK cell cytotoxicity by inhibiting surface expression of NKG2D, NKp44 and IFN-γ secretion. These findings suggest that one of the ways by which HAAH actively promotes tumor formation and proliferation is by inhibiting NK cell-surveillance activity.

  19. Inhibition and inactivation of equine aromatase by steroidal and non-steroidal compounds. A comparison with human aromatase inhibition.

    PubMed

    Moslemi, S; Seralini, G E

    1997-12-01

    In order to approach the detailed structure-function relationships of aromatase, we studied the inhibitory and inactivatory potencies of several steroidal androstenedione analogues (1: 4-hydroxyandrostenedione, 2: 4-acetoxyandrostenedione and 3: 7 alpha-(4'-amino)phenylthio-4-androstene-3, 17-dione) and non-steroidal imidazole derivatives (4: ketoconazole, 5: miconazole and 6: fadrozole) on equine aromatase in placental microsomes, a well established mammalian model. Human placental microsomes and the purified enzyme from equine testis were also used to compare inhibition by 1 and 2. In equine microsomes, all compounds tested exhibited a competitive inhibition, with Ki values of 4.1, 26 and 1.8 nM for 1, 2 and 3, and of 2400, 1.4 and 4 nM for 4, 5, and 6, respectively. The Km for androstenedione, the substrate mainly used in these studies, was 1.8 +/- 0.13 nM. The three non-steroidal derivatives did not inactivate equine aromatase, but 1 and 2 acted as comparable inactivators to a much higher degree than 3. Compound 1 inhibited in a similar manner (89-94%) purified or equine and human microsomal aromatases, whereas 2 inhibited microsomal aromatase more efficiently in the horse than in man (92% and 33% inhibition, respectively). There was only a 40% inhibition with 2 on the purified equine enzyme, which is no more in the natural membrane environment. The comparisons between equine and human microsomal aromatases allow precise functional and structural differences to be observed with these enzymes.

  20. Local Anesthetics Inhibit the Growth of Human Hepatocellular Carcinoma Cells.

    PubMed

    Le Gac, Grégoire; Angenard, Gaëlle; Clément, Bruno; Laviolle, Bruno; Coulouarn, Cédric; Beloeil, Hélène

    2017-08-29

    Hepatocellular carcinoma (HCC) is an aggressive cancer with limited therapeutic options. Retrospective studies have shown that the administration of local anesthetics (LAs) during cancer surgery could reduce cancer recurrence. Besides, experimental studies reported that LAs could inhibit the growth of cancer cells. Thus, the purpose of this study was to investigate the effects of LAs on human HCC cells. The effects of 2 LAs (lidocaine and ropivacaine) (10 to 10 M) were studied after an incubation of 48 hours on 2 HCC cell lines, namely HuH7 and HepaRG. Cell viability, cell cycle analysis, and apoptosis and senescence tests were performed together with unsupervised genome-wide expression profiling and quantitative real-time polymerase chain reaction for relevant genes. We showed that LAs decreased viability and proliferation of HuH7 cells (from 92% [P < .001] at 5 × 10 M to 40% [P = .02] at 10 M with ropivacaine and from 87% [P < .001] to 37% [P = .02] with lidocaine) and HepaRG progenitor cells (from 58% at 5 × 10 M [P < .001] to 29% at 10 M [P = .04] with lidocaine and 59% [P < .001] with ropivacaine 5 × 10 M) in concentration-dependent manner. LAs have no effect on well-differentiated HepaRG. Ropivacaine decreased the mRNA level of key cell cycle regulators, namely cyclin A2, cyclin B1, cyclin B2, and cyclin-dependent kinase 1, and the expression of the nuclear marker of cell proliferation MKI67. Lidocaine had no specific effect on cell cycle but increased by 10× the mRNA level of adenomatous polyposis coli (P < .01), which acts as an antagonist of the Wnt/β-catenin pathway. Both LAs increased apoptosis in Huh7 and HepaRG progenitor cells (P < .01). The data demonstrate that LAs induced profound modifications in gene expression profiles of tumor cells, including modulations in the expression of cell cycle-related genes that result in a cytostatic effect and induction of apoptosis.

  1. 3-Bromopyruvate inhibits human gastric cancer tumor growth in nude mice via the inhibition of glycolysis.

    PubMed

    Xian, Shu-Lin; Cao, Wei; Zhang, Xiao-Dong; Lu, Yun-Fei

    2015-02-01

    Tumor cells primarily depend upon glycolysis in order to gain energy. Therefore, the inhibition of glycolysis may inhibit tumor growth. Our previous study demonstrated that 3-bromopyruvate (3-BrPA) inhibited gastric cancer cell proliferation in vitro. However, the ability of 3-BrPA to suppress tumor growth in vivo, and its underlying mechanism, have yet to be elucidated. The aim of the present study was to investigate the inhibitory effect of 3-BrPA in an animal model of gastric cancer. It was identified that 3-BrPA exhibited strong inhibitory effects upon xenograft tumor growth in nude mice. In addition, the antitumor function of 3-BrPA exhibited a dose-effect association, which was similar to that of the chemotherapeutic agent, 5-fluorouracil. Furthermore, 3-BrPA exhibited low toxicity in the blood, liver and kidneys of the nude mice. The present study hypothesized that the inhibitory effect of 3-BrPA is achieved through the inhibition of hexokinase activity, which leads to the downregulation of B-cell lymphoma 2 (Bcl-2) expression, the upregulation of Bcl-2-associated X protein expression and the subsequent activation of caspase-3. These data suggest that 3-BrPA may be a novel therapy for the treatment of gastric cancer.

  2. Growth inhibition of Streptococcus mutans by cellular extracts of human intestinal lactic acid bacteria.

    PubMed Central

    Ishihara, K; Miyakawa, H; Hasegawa, A; Takazoe, I; Kawai, Y

    1985-01-01

    The in vitro growth of Streptococcus mutans was completely inhibited by water-soluble extracts from cells of various intestinal lactic acid bacteria identified as Streptococcus faecium, Streptococcus equinus, Lactobacillus fermentum, and Lactobacillus salivarius. The growth inhibition was dependent on the concentrations of the extracts. In contrast, the extracts did not inhibit the growth of the major indigenous intestinal lactic acid bacteria isolated from humans. These lactic acid bacteria were not acutely toxic in mice. PMID:4030098

  3. Inhibition of iron absorption from human milk by baby food.

    PubMed

    Oski, F A; Landaw, S A

    1980-05-01

    We measured the effect of a common baby food, strained pears, on the absorption of iron from human milk. Five adult subjects were initially fed 1 dL of human milk that contained added ferrous citrate Fe 59; the same subjects were later fed human milk and one jar of baby food. Incorporation of 59Fe into RBCs averaged approximately one quarter of the administered iron from the human milk. When the milk was combined with the baby food, incorporation was significantly decreased. The addition of a supplemental food to the diet of the breast-fed infant impairs the bioavailability of the iron from human milk.

  4. Growth inhibition of human pancreatic cancer cells by human interferon-beta gene combined with gemcitabine.

    PubMed

    Endou, Masato; Mizuno, Masaaki; Nagata, Takuya; Tsukada, Kazuhiro; Nakahara, Norimoto; Tsuno, Takaya; Osawa, Hirokatsu; Kuno, Tomohiko; Fujita, Mitsugu; Hatano, Manabu; Yoshida, Jun

    2005-02-01

    We examined the anti-tumor effect of cationic multilamellar liposome containing human IFN-beta (huIFN-beta) gene against cultured human pancreatic cancer cells. We also evaluated the combined effect of huIFN-beta gene entrapped in liposomes and gemcitabine. Furthermore, we examined the anti-tumor mechanisms of the therapy, with emphasis on the Ras-related signal pathway. Three human pancreatic cancer cell lines (AsPc-1, MIAPaCa-2, and PANC-1) were used in this study. The growth inhibition together with the therapy were evaluated by WST-1 assay; the production of huIFN-beta protein was measured by ELISA; the cell cycle and apoptosis were analyzed using a FACScan flow cytometer; the protein levels of Son of sevenless (SOS-1) and Ras-GAP were measured by Western blotting; and the activation of Ras-GTP was evaluated by the immunoprecipitation method. As a result, we found that huIFN-beta gene entrapped in liposomes demonstrated a strong anti-tumor effect against human pancreatic cancer cells. The treatment that combined huIFN-beta gene entrapped in liposomes and gemcitabine was more effective than each treatment alone. Although gemcitabine remarkably reduced the level of SOS-1, the above combined therapy reduced the level of SOS-1 even more significantly. Both huIFN-beta gene entrapped in liposomes and the com-bination of huIFN-beta gene entrapped in liposomes and gemcitabine increased the level of Ras-GAP, and decreased the activity of Ras-GTP. These results suggest that this combination therapy can induce strong anti-tumor activity against human pancreatic cancer cells through the regulation of the Ras-related signal pathway.

  5. Inhibition processes are dissociable and lateralized in human prefrontal cortex.

    PubMed

    Cipolotti, Lisa; Spanò, Barbara; Healy, Colm; Tudor-Sfetea, Carina; Chan, Edgar; White, Mark; Biondo, Francesca; Duncan, John; Shallice, Tim; Bozzali, Marco

    2016-12-01

    The prefrontal cortex (PFC) is known to make fundamental contributions to executive functions. However, the precise nature of these contributions is incompletely understood. We focused on a specific executive function, inhibition, the ability to suppress a pre-potent response. Functional imaging and animal studies have studied inhibition. However, there are only few lesion studies, typically reporting discrepant findings. For the first time, we conducted cognitive and neuroimaging investigations on patients with focal unilateral PFC lesions across two widely used inhibitory tasks requiring a verbal response: The Hayling Part 2 and Stroop Colour-Word Tests. We systematically explored the relationship between inhibition, fluid intelligence and lesion location using voxel-based lesion symptom mapping (VLSM). We found that PFC patients were significantly impaired compared with healthy comparison group (HC) on both suppression measures of the Hayling and on the Stroop, even when performance on a fluid intelligence test was covaried. No significant relationship was found between patients' performance on each Hayling suppression measure and the Stroop, once fluid intelligence was partialled out, suggesting that the two tests may involve different kinds of inhibition. After accounting for fluid intelligence, we found a significant interaction between tests, Hayling or Stroop, and site, left or right, of PFC damage. This finding suggesting lateralized functional organization was complemented and extended by our VLSM results. We found that performance on both Hayling suppression measures significantly relied on the integrity of a similar and relatively circumscribed region within the right lateral PFC, in the right lateral superior and middle frontal gyri. In stark contrast, performance on the Stroop relies on the integrity of left lateral superior and middle frontal gyri. Thus, lesion location, right or left PFC, is critical in producing impairments on two inhibitory tasks

  6. Inhibition of osteogenic differentiation of human mesenchymal stem cells

    PubMed Central

    Moioli, Eduardo K.; Hong, Liu; Mao, Jeremy J.

    2010-01-01

    Mesenchymal stem cells (hMSCs) have been shown to differentiate into osteoblasts that, in turn, are capable of forming tissues analogous to bone. The present study was designed to investigate the inhibition of osteogenesis by hMSCs. Bone marrow-derived hMSCs were treated with transforming growth factor β-3 (TGFβ3) at various doses during or after their differentiation into osteogenic cells. TGFβ3 was encapsulated in poly(DL-lactic-co-glycolic acid) (PLGA) microspheres and released via controlled delivery in the osteogenic culture of hMSCs and hMSC-derived osteoblasts for up to 28 days. Controlled release of TGFβ3 inhibited the osteogenic differentiation of hMSCs, as evidenced by significantly reduced alkaline phosphatase activity and staining, as well as decreased mineral deposition. After hMSCs had been differentiated into osteoblasts, controlled release of TGFβ3 further inhibited not only alkaline phosphatase and mineral deposition but also osteocalcin expression. These findings demonstrate the potential for sustained modulation of the behavior of stem cells and/or stem cell-derived lineage-specific cells via controlled release of growth factor(s). The attenuation of osteogenic differentiation of MSCs may facilitate understanding not only the regulation and patterning of osteogenesis in development but also several pathological models such as osteopetrosis, craniosynostosis, and heart valve calcification. PMID:17537129

  7. Ring Expanded Nucleoside Analogues Inhibit RNA Helicase and Intracellular Human Immunodeficiency virus type 1 Replication

    PubMed Central

    Yedavalli, Venkat S.R.K; Zhang, Ning; Cai, Hongyi; Zhang, Peng; Starost, Matthew F.; Hosmane, Ramachandra S.; Jeang, Kuan-Teh

    2008-01-01

    A series of ring expanded nucleoside (REN) analogues were synthesized and screened for inhibition of cellular RNA helicase activity and human immunodeficiency virus type 1 (HIV-1) replication. We identified two compounds 1 and 2 that inhibited the ATP dependent activity of human RNA helicase DDX3. Compounds 1 and 2 also suppressed HIV-1 replication in T cells and monocyte-derived macrophages. Neither compound at therapeutic doses was significantly toxic in ex vivo cell culture or in vivo in mice. Our findings provide proof-of-concept that a cellular factor, an RNA helicase, could be targeted for inhibiting HIV-1 replication. PMID:18680273

  8. Gossypol enantiomers potently inhibit human placental 3β-hydroxysteroid dehydrogenase 1 and aromatase activities.

    PubMed

    Dong, Yaoyao; Mao, Baiping; Li, Linxi; Guan, Hongguo; Su, Ying; Li, Xiaoheng; Lian, Qingquan; Huang, Ping; Ge, Ren-Shan

    2016-03-01

    Gossypol is a chemical isolated from cotton seeds. It exists as (+) or (-) enantiomer and has been tested for anticancer, abortion-inducing, and male contraception. Progesterone formed from pregnenolone by 3β-hydroxysteroid dehydrogenase 1 (HSD3B1) and estradiol from androgen by aromatase (CYP19A1) are critical for the maintenance of pregnancy or associated with some cancers. In this study we compared the potencies of (+)- and (-)-gossypol enantiomers in the inhibition of HSD3B1 and aromatase activities as well as progesterone and estradiol production in human placental JEG-3 cells. (+) Gossypol showed potent inhibition on human placental HSD3B1 with IC50 value of 2.3 μM, while (-) gossypol weakly inhibited it with IC50 over 100 μM. In contrast, (-) gossypol moderately inhibited CYP19A1 activity with IC50 of 23 μM, while (+) gossypol had no inhibition when the highest concentration (100 μM) was tested. (+) Gossypol enantiomer competitively inhibited HSD3B1 against substrate pregnenolone and showed mixed mode against NAD(+). (-) Gossypol competitively inhibited CYP19A1 against substrate testosterone. Gossypol enantiomers showed different potency related to their inhibition on human HSD3B1 and CYP19A1. Whether gossypol enantiomer is used alone or in combination relies on its application and beneficial effects.

  9. Targeting Notch1 inhibits invasion and angiogenesis of human breast cancer cells via inhibition Nuclear Factor-κB signaling

    PubMed Central

    Liu, Yuan; Su, Chuanfu; Shan, Yuqing; Yang, Shouxiang; Ma, Guifeng

    2016-01-01

    Notch-1, a type-1 transmembrane protein, plays critical roles in the pathogenesis and progression of human malignancies, including breast cancer; however, the precise mechanism by which Notch-1 causes tumor cell invasion and angiogenesis remain unclear. Nuclear factor-κB (NF-κB), interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMP) are critically involved in the processes of tumor cell invasion and metastasis, we investigated whether targeting Notch-1 could be mechanistically associated with the down-regulation of NF-κB, IL-8, VEGF, and MMP-9, resulting in the inhibition of invasion and angiogenesis of breast cancer cells. Our data showed that down-regulation of Notch-1 leads to the inactivation of NF-κB activity and inhibits the expression of its target genes, such as IL-8, VEGF and MMP-9. We also found that down-regulation of Notch-1 decreased cell invasion, and vice versa Consistent with these results, we also found that the down-regulation of Notch-1 not only decreased MMP-9 mRNA and its protein expression but also inhibited MMP-9 active form. Moreover, conditioned medium from Notch-1 siRNA-transfected breast cancer cells showed reduced levels of IL-8 and VEGF and, in turn, inhibited the tube formation of HUVECs, suggesting that down-regulation of Notch-1 leads to the inhibition of angiogenesis. Furthermore, conditioned medium from Notch-1 cDNA-transfected breast cancer cells showed increased levels of IL-8 and VEGF and, in turn, promoted the tube formation of HUVECs, suggesting that Notch-1 overexpression leads to the promotion of angiogenesis.We therefore concluded that down-regulation of Notch-1 leads to the inactivation NF-κB and its target genes (IL-8, MMP-9 and VEGF), resulting in the inhibition of invasion and angiogenesis. PMID:27398151

  10. Phentermine inhibition of recombinant human liver monoamine oxidases A and B.

    PubMed

    Nandigama, Ravi K; Newton-Vinson, Paige; Edmondson, Dale E

    2002-03-01

    Recent studies with rat tissue preparations have suggested that the anorectic drug phentermine inhibits serotonin degradation by inhibition of monoamine oxidase (MAO) A with a K(I) value of 85-88 microM, a potency suggested to be similar to that of other reversible MAO inhibitors (Ulus et al., Biochem Pharmacol 2000;59:1611-21). Since there are known differences between rats and humans in substrate and inhibitor specificities of MAOs, the interactions of phentermine with recombinant human purified preparations of MAO A and MAO B were determined. Human MAO A was competitively inhibited by phentermine with a K(I) value of 498+/-60 microM, a value approximately 6-fold weaker than that observed for the rat enzyme. Phentermine was also observed to be a competitive inhibitor of recombinant human liver MAO B with a K(I) value of 375+/-42 microM, a value similar to that observed with the rat enzyme (310-416 microM). In contrast to the behavior with rat tissue preparations, no slow time-dependent behavior was observed for phentermine inhibition of purified soluble human MAO preparations. Difference absorption spectral studies showed similar perturbations of the covalent FAD moieties of both human MAO A and MAO B, which suggests a similar mode of binding in both enzymes. These data suggest that phentermine inhibition of human MAO A (or of MAO B) is too weak to be of pharmacological relevance.

  11. Apigenin inhibits NF-κB and Snail signaling, EMT and metastasis in human hepatocellular carcinoma

    PubMed Central

    Zhong, Wei-long; Chen, Shuang; Gu, Wen-guang; Wang, Wei; Zhang, Chun-hong; Liu, Yan-rong; Liu, Hui-juan; Zhang, Qiang; Guo, Yuan-qiang; Sun, Tao; Yang, Cheng

    2016-01-01

    Apigenin is a naturally occurring compound with anti-inflammatory, antioxidant, and anticancer properties. In this study, we investigated the effects of apigenin on migration and metastasis in experimental human hepatocellular carcinoma (HCC) cell lines in vitro and in vivo. Apigenin dose-dependently inhibited proliferation, migration, and invasion by PLC and Bel-7402 human HCC cells. It also suppressed tumor growth in PLC cell xenografts without altering body weight, thereby prolonging survival. Apigenin reduced Snai1 and NF-κB expression, reversed increases in epithelial-mesenchymal transition (EMT) marker levels, increased cellular adhesion, regulated actin polymerization and cell migration, and inhibited invasion and migration by HCC cells. Apigenin may therefore inhibit EMT by inhibiting the NF-κB/Snail pathway in human HCC. PMID:27203387

  12. Design, synthesis, and characterization of novel, nonquaternary reactivators of GF-inhibited human acetylcholinesterase.

    PubMed

    McHardy, Stanton F; Bohmann, Jonathan A; Corbett, Michael R; Campos, Bismarck; Tidwell, Michael W; Thompson, Paul Marty; Bemben, Chris J; Menchaca, Tony A; Reeves, Tony E; Cantrell, William R; Bauta, William E; Lopez, Ambrosio; Maxwell, Donald M; Brecht, Karen M; Sweeney, Richard E; McDonough, John

    2014-04-01

    The goal of this research was to identify structurally novel, non-quaternarypyridinium reactivators of GF (cyclosarin)-inhibited hAChE that possess the capacity to mediate in vitro reactivation of GF-inhibited human acetylcholinesterase (hAChE). New compounds were designed, synthesized and assessed in GF-inhibited hAChE assays. Structure activity relationships for AChE binding and reactivation of GF-inhibited hAChE were developed. Lead compounds from two different chemical series, represented by compounds 17 and 38, displayed proficient in vitro reactivation of GF-inhibited hAChE, while also possessing low inhibition of native enzyme. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Ethanol inhibits human bone cell proliferation and function in vitro

    SciTech Connect

    Friday, K.E.; Howard, G.A. )

    1991-06-01

    The direct effects of ethanol on human bone cell proliferation and function were studied in vitro. Normal human osteoblasts from trabecular bone chips were prepared by collagenase digestion. Exposure of these osteoblasts to ethanol in concentrations of 0.05% to 1% for 22 hours induced a dose-dependent reduction in bone cell DNA synthesis as assessed by incorporation of 3H-thymidine. After 72 hours of ethanol exposure in concentrations of 0.01% to 1%, protein synthesis as measured by 3H-proline incorporation into trichbroacetic acid (TCA)-precipitable material was reduced in a dose-dependent manner. Human bone cell protein concentrations and alkaline phosphatase total activity were significantly reduced after exposure to 1% ethanol for 72 hours, but not with lower concentrations of ethanol. This reduction in osteoblast proliferation and activity may partially explain the development of osteopenia in humans consuming excessive amounts of ethanol.

  14. Long-interval intracortical inhibition in a human hand muscle.

    PubMed

    McNeil, Chris J; Martin, Peter G; Gandevia, Simon C; Taylor, Janet L

    2011-03-01

    When two motor cortical stimuli are delivered with an interstimulus interval of 50-200 ms, the response (motor evoked potential; MEP) to the second stimulus is typically suppressed. This phenomenon is termed long-interval intracortical inhibition (LICI), although data from one subject suggest that facilitation is possible. Moreover, we recently showed that suppression can be mediated at a spinal level. We characterized LICI more fully by exploring a broad range of contraction strengths and test stimulus intensities. MEPs were evoked in first dorsal interosseous by transcranial magnetic stimulation over the motor cortex. Single test and paired (conditioning-test interval of 100 ms) stimuli at intensities of 100-160% resting motor threshold were delivered at rest or during brief contractions of 10, 25, or 100% maximal voluntary force. Inhibition or facilitation was quantified with the standard ratio in which conditioned MEPs were expressed as a percentage of unconditioned MEPs. Inhibition was greatest at weak-moderate contraction strengths and least at rest and during maximal efforts. Both at rest and during maximal efforts, MEPs evoked by strong stimuli were facilitated. In a subset of subjects, cervicomedullary stimulation was used to activate the corticospinal tract to identify possible spinal influences on changes to MEPs. Contraction strength and test stimulus intensity each had different effects on unconditioned and conditioned MEP size, and hence, LICI is highly dependent on both factors. Further, because motoneurons are facilitated during contraction but disfacilitated after a strong conditioning stimulus, the standard ratio of LICI is of questionable validity during voluntary contractions.

  15. Human red cells scavenge extracellular hydrogen peroxide and inhibit formation of hypochlorous acid and hydroxyl radical.

    PubMed Central

    Winterbourn, C C; Stern, A

    1987-01-01

    The ability of intact human red cells to scavenge extracellularly generated H2O2 and O2-, and to prevent formation of hydroxyl radicals and hypochlorous acid has been examined. Red cells inhibited oxidation of ferrocytochrome c by H2O2. Cells treated with aminotriazole no longer inhibited, indicating that protection was almost entirely due to intracellular catalase. Contribution by the GSH system was slight, and apparent only with low H2O2 concentrations when catalase was inhibited by aminotriazole. The cells were about a quarter as efficient at inhibiting cytochrome c oxidation as an equivalent concentration of purified catalase. No inhibition of O2(-)-dependent reduction of ferricytochrome c or nitroblue tetrazolium was observed, although extracted red cell superoxide dismutase inhibited nitroblue tetrazolium reduction at one fortieth the concentration of that in the cells. Red cells efficiently inhibited deoxyribose oxidation by hydroxyl radicals generated from H2O2, O2- and Fe(EDTA), and myeloperoxidase-dependent oxidation of methionine to methionine sulfoxide by stimulated neutrophils. Most of the red cell inhibition of hydroxyl radical production, and all the inhibition of methionine oxidation, was prevented by blocking intracellular catalase with aminotriazole. Thus red cells are able to efficiently scavenge H2O2, but not O2-, produced in their environment, and to inhibit formation of hydroxyl radicals and hypochlorous acid. They may therefore have an important role in extracellular antioxidant defense. PMID:2824562

  16. P2×7 targeting inhibits growth of human mesothelioma

    PubMed Central

    Amoroso, Francesca; Salaro, Erica; Falzoni, Simonetta; Chiozzi, Paola; Giuliani, Anna Lisa; Cavallesco, Giorgio; Maniscalco, Pio; Puozzo, Andrea; Bononi, Ilaria; Martini, Fernanda; Tognon, Mauro; Virgilio, Francesco Di

    2016-01-01

    Malignant pleural mesothelioma (MPM) is an aggressive tumor refractory to anti-blastic therapy. MPM cells show several genetic and biochemical defects, e.g. overexpression of oncogenes, downregulation of onco-suppressor genes, dysregulation of microRNA, or alteration of intracellular Ca2+ homeostasis and of apoptosis. No information is as yet available on purinergic signalling in this tumor. Signalling via the P2×7 (P2RX7 or P2×7R) purinergic receptor is attracting increasing attention as a pathway involved in cancer cell death or proliferation. In this report we show that the P2×7R is expressed by three MPM cell lines established from MPM patients but not by mesothelial cells from healthy subjects (healthy mesothelial cells, HMCs). MPM cell proliferation was inhibited by in vitro incubation in the presence of selective P2×7R antagonists, as well as by stimulation with the P2×7R agonist BzATP. Systemic administration of the selective P2×7R blocker AZ10606120 inhibited in vivo growth of MPM tumors whether implanted subcutaneously (s.c.) or intraperitoneally (i.p.). Our findings suggest that the P2×7R might be a novel target for the therapy of mesothelioma. PMID:27391069

  17. Hemispheric asymmetry and somatotopy of afferent inhibition in healthy humans.

    PubMed

    Helmich, R C G; Bäumer, T; Siebner, H R; Bloem, B R; Münchau, A

    2005-11-01

    A conditioning electrical stimulus to a digital nerve can inhibit the motor-evoked potentials (MEPs) in adjacent hand muscles elicited by transcranial magnetic stimulation (TMS) to the contralateral primary motor cortex (M1) when given 25-50 ms before the TMS pulse. This is referred to as short-latency afferent inhibition (SAI). We studied inter-hemispheric differences (Experiment 1) and within-limb somatotopy (Experiment 2) of SAI in healthy right-handers. In Experiment 1, conditioning electrical pulses were applied to the right or left index finger (D2) and MEPs were recorded from relaxed first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles ipsilateral to the conditioning stimulus. We found that SAI was more pronounced in right hand muscles. In Experiment 2, electrical stimulation was applied to the right D2 and MEPs were recorded from ipsilateral FDI, extensor digitorum communis (EDC) and biceps brachii (BB) muscles. The amount of SAI did not differ between FDI, EDC and BB muscles. These data demonstrate inter-hemispheric differences in the processing of cutaneous input from the hand, with stronger SAI in the dominant left hemisphere. We also found that SAI occurred not only in hand muscles adjacent to electrical digital stimulation, but also in distant hand and forearm and also proximal arm muscles. This suggests that SAI induced by electrical D2 stimulation is not focal and somatotopically specific, but a more widespread inhibitory phenomenon.

  18. Bovine Lactoferrampin, Human Lactoferricin, and Lactoferrin 1-11 Inhibit Nuclear Translocation of HIV Integrase.

    PubMed

    Wang, Winston Yan; Wong, Jack Ho; Ip, Denis Tsz Ming; Wan, David Chi Cheong; Cheung, Randy Chifai; Ng, Tzi Bun

    2016-08-01

    This study aimed to investigate fragments derived from human and bovine lactoferrins for ability to inhibit nuclear translocation of HIV-1 integrase. It was shown that human lactoferricin, human lactoferrin 1-11, and bovine lactoferrampin reduced nuclear distribution of HIV-1 integrase. Bovine lactoferrampin could inhibit both the activity and nuclear translocation of HIV-1 integrase. Human lactoferrampin, bovine lactoferricin, and bovine lactoferrin 1-11 had no effect on HIV-1 integrase nuclear translocation. Human lactoferrampin which inhibited the activity of integrase did not prevent its nuclear translocation. Human lactoferricin and lactoferrin 1-11 did not inhibit HIV-1 integrase nuclear translocation despite their ability to attenuate the enzyme activity. The discrepancy between the findings on reduction of HIV-1 activity and inhibition of nuclear translocation of HIV-1 integrase was due to the different mechanisms involved. A similar reasoning can also be applied to the different inhibitory potencies of the milk peptides on different HIV enzymes, i.e., nuclear translocation.

  19. DIETARY ISOTHIOCYANATE IBERIN INHIBITS GROWTH AND INDUCES APOPTOSIS IN HUMAN GLIOBLASTOMA CELLS

    USDA-ARS?s Scientific Manuscript database

    In this study, we evaluated the antiproliferative and proapoptotic effects of the isothiocyanate iberin, a bioactive agent in Brassicaceae species, in human glioblastoma cells. The human glioblastoma cell cultures were treated with different concentrations of iberin and tested for growth inhibition...

  20. Feed-forward inhibition of androgen receptor activity by glucocorticoid action in human adipocytes.

    PubMed

    Hartig, Sean M; He, Bin; Newberg, Justin Y; Ochsner, Scott A; Loose, David S; Lanz, Rainer B; McKenna, Neil J; Buehrer, Benjamin M; McGuire, Sean E; Marcelli, Marco; Mancini, Michael A

    2012-09-21

    We compared transcriptomes of terminally differentiated mouse 3T3-L1 and human adipocytes to identify cell-specific differences. Gene expression and high content analysis (HCA) data identified the androgen receptor (AR) as both expressed and functional, exclusively during early human adipocyte differentiation. The AR agonist dihydrotestosterone (DHT) inhibited human adipocyte maturation by downregulation of adipocyte marker genes, but not in 3T3-L1. It is interesting that AR induction corresponded with dexamethasone activation of the glucocorticoid receptor (GR); however, when exposed to the differentiation cocktail required for adipocyte maturation, AR adopted an antagonist conformation and was transcriptionally repressed. To further explore effectors within the cocktail, we applied an image-based support vector machine (SVM) classification scheme to show that adipocyte differentiation components inhibit AR action. The results demonstrate human adipocyte differentiation, via GR activation, upregulates AR but also inhibits AR transcriptional activity.

  1. Structural Basis for Norovirus Inhibition by Human Milk Oligosaccharides

    PubMed Central

    Weichert, Stefan; Koromyslova, Anna; Singh, Bishal K.; Hansman, Satoko; Jennewein, Stefan; Schroten, Horst

    2016-01-01

    Histo-blood group antigens (HBGAs) are important binding factors for norovirus infections. We show that two human milk oligosaccharides, 2′-fucosyllactose (2′FL) and 3-fucosyllactose (3FL), could block norovirus from binding to surrogate HBGA samples. We found that 2′FL and 3FL bound at the equivalent HBGA pockets on the norovirus capsid using X-ray crystallography. Our data revealed that 2′FL and 3FL structurally mimic HBGAs. These results suggest that 2′FL and 3FL might act as naturally occurring decoys in humans. PMID:26889023

  2. Inhibition of human pathogenic fungi by ethnobotanically selected plant extracts.

    PubMed

    Ficker, Christine E; Arnason, J T; Vindas, P S; Alvarez, L P; Akpagana, K; Gbéassor, M; De Souza, C; Smith, M L

    2003-02-01

    In this study, 36 extracts derived from 29 plant species selected using an ethnobotanical approach were tested for antifungal activity against a taxonomically diverse group of 13 human pathogenic fungi. We compared the inhibitory characteristics of these plant extracts with those of the commonly used antifungals, amphotericin B and ketoconazole, and the plant-derived antifungal, berberine. Several plant extracts, notably those from Zingiber officinale (ginger) and Juglans cinerea (butternut), had pronounced antifungal activity against a wide variety of fungi, including strains that were highly resistant to amphotericin B and ketoconazole. Further exploration of Z. officinale as an antifungal is warranted as this species is generally regarded as safe for human consumption.

  3. [Human antitumor immunity according to leukocyte adherence inhibition test data].

    PubMed

    Riatsep, V I; Kurtenkov, O A; Nikitin, Iu G; Miliukhina, L M

    1980-01-01

    A microvariant of the test of leucocytes adherence inhibition, which results were assessed by fluorescence, has revealed antitumor immune reactions to allogenic tumor antigens in gastric cancer (n = 38) and breast cancer (n = 35) in 51.7 and 68.5% of patients respectively. A correlation between the reaction and stage was found only in breast cancer patients. Postive reactions to heterogenous tumor antigen were noted in 17-25% of cases. The reactions to tumor antigens in nontumor lesions of the corresponding localizations were noted in 29.2 and 25%. The data obtained indicated that homogeneity of the antigenic tumor pattern is high enough within the limits of a particular localization irrespective of the degree of morphological tumor differentiation. It seems essential to take into account some possible autoimmune reactions to normal organotypical antigens to interprete the tumor specificity of the reactions under study.

  4. Olopatadine hydrochloride inhibits capsaicin-induced flare response in humans.

    PubMed

    Shindo, Masahisa; Yoshida, Yuichi; Yamamoto, Osamu

    2011-01-01

    Capsaicin, a vanilloid, has the potential for releasing substance P (SP) from sensory nerves. Topical application of capsaicin induces a flare response in the skin. However, it has not been clarified whether the release of SP is involved in the process of flare response or not. A potent antihistamine drug, olopatadine hydrochloride, is known to have inhibitory action against the release of SP. We examined the effects of olopatadine (at a dose of 5 mg) on skin reaction induced by topical application of capsaicin in 10 healthy subjects. The scores of capsaicin-induced flare responses after olopatadine administration were significantly lower at 30 min than at baseline. Our findings suggest that olopatadine hydrochloride could inhibit capsaicin-induced flare responses. Copyright © 2011 S. Karger AG, Basel.

  5. HIV-1 Vpr inhibits cytokinesis in human proximal tubule cells.

    PubMed

    Rosenstiel, Paul E; Gruosso, Tina; Letourneau, Audrey M; Chan, Justin J; LeBlanc, Amanda; Husain, Mohammad; Najfeld, Vesna; Planelles, Vicente; D'Agati, Vivette D; Klotman, Mary E; Klotman, Paul E

    2008-10-01

    Transgenic mouse models of HIV-associated nephropathy (HIVAN) show that expression of HIV-1 genes in kidney cells produces collapsing focal segmental glomerulosclerosis and microcystic tubular disease typical of the human disease. HIV-1 vpr plays an important role in the glomerulosclerosis of HIVAN, especially when it is associated with nef expression in podocytes. Further, Vpr is reported to exacerbate tubular pathology. Here we determined effects of vpr expression on renal tubular epithelial cell function by transducing them with a pseudotyped lentivirus vector carrying HIV-1 vpr and control genes. Vpr expression in the cultured cells impaired cytokinesis causing cell enlargement and multinucleation. This profound in vitro phenotype caused us to reexamine the HIVAN mouse model and human HIVAN biopsies to see if similar changes occur in vivo. Both showed abundant hypertrophic tubule cells similar to the in vitro finding that represents a previously unappreciated aspect of the human disease. Additionally, multinucleated tubular cells were identified in the murine HIVAN model and increased chromosome number was detected in tubular cells of human HIVAN biopsies. Our study provides evidence of a new clinical phenotype in HIVAN that may result from the ability of Vpr to impair cytokinesis.

  6. Curcumin inhibits Rift Valley fever virus replication in human cells.

    PubMed

    Narayanan, Aarthi; Kehn-Hall, Kylene; Senina, Svetlana; Lundberg, Lindsay; Van Duyne, Rachel; Guendel, Irene; Das, Ravi; Baer, Alan; Bethel, Laura; Turell, Michael; Hartman, Amy Lynn; Das, Bhaskar; Bailey, Charles; Kashanchi, Fatah

    2012-09-28

    Rift Valley fever virus (RVFV) is an arbovirus that is classified as a select agent, an emerging infectious virus, and an agricultural pathogen. Understanding RVFV-host interactions is imperative to the design of novel therapeutics. Here, we report that an infection by the MP-12 strain of RVFV induces phosphorylation of the p65 component of the NFκB cascade. We demonstrate that phosphorylation of p65 (serine 536) involves phosphorylation of IκBα and occurs through the classical NFκB cascade. A unique, low molecular weight complex of the IKK-β subunit can be observed in MP-12-infected cells, which we have labeled IKK-β2. The IKK-β2 complex retains kinase activity and phosphorylates an IκBα substrate. Inhibition of the IKK complex using inhibitors impairs viral replication, thus alluding to the requirement of an active IKK complex to the viral life cycle. Curcumin strongly down-regulates levels of extracellular infectious virus. Our data demonstrated that curcumin binds to and inhibits kinase activity of the IKK-β2 complex in infected cells. Curcumin partially exerts its inhibitory influence on RVFV replication by interfering with IKK-β2-mediated phosphorylation of the viral protein NSs and by altering the cell cycle of treated cells. Curcumin also demonstrated efficacy against ZH501, the fully virulent version of RVFV. Curcumin treatment down-regulated viral replication in the liver of infected animals. Our data point to the possibility that RVFV infection may result in the generation of novel versions of host components (such as IKK-β2) that, by virtue of altered protein interaction and function, qualify as unique therapeutic targets.

  7. Curcumin Inhibits Rift Valley Fever Virus Replication in Human Cells*

    PubMed Central

    Narayanan, Aarthi; Kehn-Hall, Kylene; Senina, Svetlana; Lundberg, Lindsay; Van Duyne, Rachel; Guendel, Irene; Das, Ravi; Baer, Alan; Bethel, Laura; Turell, Michael; Hartman, Amy Lynn; Das, Bhaskar; Bailey, Charles; Kashanchi, Fatah

    2012-01-01

    Rift Valley fever virus (RVFV) is an arbovirus that is classified as a select agent, an emerging infectious virus, and an agricultural pathogen. Understanding RVFV-host interactions is imperative to the design of novel therapeutics. Here, we report that an infection by the MP-12 strain of RVFV induces phosphorylation of the p65 component of the NFκB cascade. We demonstrate that phosphorylation of p65 (serine 536) involves phosphorylation of IκBα and occurs through the classical NFκB cascade. A unique, low molecular weight complex of the IKK-β subunit can be observed in MP-12-infected cells, which we have labeled IKK-β2. The IKK-β2 complex retains kinase activity and phosphorylates an IκBα substrate. Inhibition of the IKK complex using inhibitors impairs viral replication, thus alluding to the requirement of an active IKK complex to the viral life cycle. Curcumin strongly down-regulates levels of extracellular infectious virus. Our data demonstrated that curcumin binds to and inhibits kinase activity of the IKK-β2 complex in infected cells. Curcumin partially exerts its inhibitory influence on RVFV replication by interfering with IKK-β2-mediated phosphorylation of the viral protein NSs and by altering the cell cycle of treated cells. Curcumin also demonstrated efficacy against ZH501, the fully virulent version of RVFV. Curcumin treatment down-regulated viral replication in the liver of infected animals. Our data point to the possibility that RVFV infection may result in the generation of novel versions of host components (such as IKK-β2) that, by virtue of altered protein interaction and function, qualify as unique therapeutic targets. PMID:22847000

  8. Comparison of oxime reactivation and aging of nerve agent-inhibited monkey and human acetylcholinesterases.

    PubMed

    Luo, Chunyuan; Tong, Min; Maxwell, Donald M; Saxena, Ashima

    2008-09-25

    Non-human primates are valuable animal models that are used for the evaluation of nerve agent toxicity as well as antidotes and results from animal experiments are extrapolated to humans. It has been demonstrated that the efficacy of an oxime primarily depends on its ability to reactivate nerve agent-inhibited acetylcholinesterase (AChE). If the in vitro oxime reactivation of nerve agent-inhibited animal AChE is similar to that of human AChE, it is likely that the results of an in vivo animal study will reliably extrapolate to humans. Therefore, the goal of this study was to compare the aging and reactivation of human and different monkey (Rhesus, Cynomolgus, and African Green) AChEs inhibited by GF, GD, and VR. The oximes examined include the traditional oxime 2-PAM, two H-oximes HI-6 and HLo-7, and the new candidate oxime MMB4. Results indicate that oxime reactivation of all three monkey AChEs was very similar to human AChE. The maximum difference in the second-order reactivation rate constant between human and three monkey AChEs or between AChEs from different monkey species was 5-fold. Aging rate constants of GF-, GD-, and VR-inhibited monkey AChEs were very similar to human AChE except for GF-inhibited monkey AChEs, which aged 2-3 times faster than the human enzyme. The results of this study suggest that all three monkey species are suitable animal models for nerve agent antidote evaluation since monkey AChEs possess similar biochemical/pharmacological properties to human AChE.

  9. Antisense inhibition of hyaluronan synthase-2 in human osteosarcoma cells inhibits hyaluronan retention and tumorigenicity

    SciTech Connect

    Nishida, Yoshihiro . E-mail: ynishida@med.nagoya-u.ac.jp; Knudson, Warren; Knudson, Cheryl B.; Ishiguro, Naoki

    2005-07-01

    Osteosarcoma is a common malignant bone tumor associated with childhood and adolescence. The results of numerous studies have suggested that hyaluronan plays an important role in regulating the aggressive behavior of various types of cancer cells. However, no studies have addressed hyaluronan with respect to osteosarcomas. In this investigation, the mRNA expression copy number of three mammalian hyaluronan synthases (HAS) was determined using competitive RT-PCR in the osteoblastic osteosarcoma cell line, MG-63. MG-63 are highly malignant osteosarcoma cells with an abundant hyaluronan-rich matrix. The results demonstrated that HAS-2 is the predominant HAS in MG-63. Accumulation of intracellular hyaluronan increased in association with the proliferative phase of these cells. The selective inhibition of HAS-2 mRNA in MG-63 cells by antisense phosphorothioate oligonucleotides resulted in reduced hyaluronan accumulation by these cells. As expected, the reduction in hyaluronan disrupted the assembly of cell-associated matrices. However, of most interest, coincident with the reduction in hyaluronan, there was a substantial decrease in cell proliferation, a decrease in cell motility and a decrease in cell invasiveness. These data suggest that hyaluronan synthesized by HAS-2 in MG-63 plays a crucial role in osteosarcoma cell proliferation, motility, and invasion.

  10. L-Phenylalanine inhibition of human alkaline phosphatases with p-nitrophenyl phosphate as substrate.

    PubMed

    Komoda, T; Hokari, S; Sonoda, M; Sakagishi, Y; Tamura, T

    1982-12-01

    With p-nitrophenyl phosphate as the substrate, there reportedly is no organ-specific inhibition of alkaline phosphatase (EC 3.1.3.1) activity by L-phenylalanine. However, we found that at pH 10.0, with p-nitrophenyl phosphate as the substrate, L-phenylalanine obviously inhibits the alkaline phosphatase isoenzyme from human placenta, whereas there is little if any inhibition of the isoenzyme from human intestine. Because of the differing effects of substrates (p-nitrophenyl phosphate and phenyl phosphate) and their enzymic products (p-nitrophenol and phenol) for L-phenylalanine action on the placental alkaline phosphatase isoenzyme, we suggest that the isoenzyme--inhibitor--substrate complex and the effect of released phosphate on L-phenylalanine inhibition of the isoenzyme activity differ from each other.

  11. Structural Basis of Human CYP51 Inhibition by Antifungal Azoles

    SciTech Connect

    Strushkevich, Natallia; Usanov, Sergey A.; Park, Hee-Won

    2010-09-22

    The obligatory step in sterol biosynthesis in eukaryotes is demethylation of sterol precursors at the C14-position, which is catalyzed by CYP51 (sterol 14-alpha demethylase) in three sequential reactions. In mammals, the final product of the pathway is cholesterol, while important intermediates, meiosis-activating sterols, are produced by CYP51. Three crystal structures of human CYP51, ligand-free and complexed with antifungal drugs ketoconazole and econazole, were determined, allowing analysis of the molecular basis for functional conservation within the CYP51 family. Azole binding occurs mostly through hydrophobic interactions with conservative residues of the active site. The substantial conformational changes in the B{prime} helix and F-G loop regions are induced upon ligand binding, consistent with the membrane nature of the protein and its substrate. The access channel is typical for mammalian sterol-metabolizing P450 enzymes, but is different from that observed in Mycobacterium tuberculosis CYP51. Comparison of the azole-bound structures provides insight into the relative binding affinities of human and bacterial P450 enzymes to ketoconazole and fluconazole, which can be useful for the rational design of antifungal compounds and specific modulators of human CYP51.

  12. Peptides in common bean fractions inhibit human colorectal cancer cells.

    PubMed

    Luna Vital, Diego A; González de Mejía, Elvira; Dia, Vermont P; Loarca-Piña, Guadalupe

    2014-08-15

    The aim of this study was to characterize peptides present in common bean non-digestible fractions (NDF) produced after enzymatic digestion and determine their antiproliferative action on human colorectal cancer cells. Five NDF peptides represented 70% of total protein (GLTSK, LSGNK, GEGSGA, MPACGSS and MTEEY) with antiproliferative activity on human colon cancer cells. Based on the antiproliferative effect, HCT116 cell line was most sensitive to bean Azufrado Higuera (IC50=0.53 mg/ml) and RKO to Bayo Madero (IC50=0.51 mg/ml) peptide extracts. Both cultivars increased significantly (p<0.05) the expression of p53 in HCT116 by 76% and 68%, respectively. Azufrado Higuera modified the expression of cell cycle regulation proteins p21 and cyclin B1. Bayo Madero modified the expression of mitochondrial activated apoptotic proteins BAD, cytC, c-casp3, Survivin, BIRC7. Results suggest that peptides present in common bean NDF contributed to the antiproliferative effect on human colorectal cancer cells by modifying molecules involved in either cell cycle arrest or apoptosis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Opiate receptor blockade on human granulosa cells inhibits VEGF release.

    PubMed

    Lunger, Fabian; Vehmas, Anni P; Fürnrohr, Barbara G; Sopper, Sieghart; Wildt, Ludwig; Seeber, Beata

    2016-03-01

    The objectives of this study were to determine whether the main opioid receptor (OPRM1) is present on human granulosa cells and if exogenous opiates and their antagonists can influence granulosa cell vascular endothelial growth factor (VEGF) production via OPRM1. Granulosa cells were isolated from women undergoing oocyte retrieval for IVF. Complementary to the primary cells, experiments were conducted using COV434, a well-characterized human granulosa cell line. Identification and localization of opiate receptor subtypes was carried out using Western blot and flow cytometry. The effect of opiate antagonist on granulosa cell VEGF secretion was assessed by enzyme-linked immunosorbent assay. For the first time, the presence of OPRM1 on human granulosa cells is reported. Blocking of opiate signalling using naloxone, a specific OPRM1 antagonist, significantly reduced granulosa cell-derived VEGF levels in both COV434 and granulosa-luteal cells (P < 0.01). The presence of opiate receptors and opiate signalling in granulosa cells suggest a possible role in VEGF production. Targeting this signalling pathway could prove promising as a new clinical option in the prevention and treatment of ovarian hyperstimulation syndrome.

  14. Milk Oligosaccharides Inhibit Human Rotavirus Infectivity in MA104 Cells.

    PubMed

    Laucirica, Daniel R; Triantis, Vassilis; Schoemaker, Ruud; Estes, Mary K; Ramani, Sasirekha

    2017-09-01

    Background: Oligosaccharides in milk act as soluble decoy receptors and prevent pathogen adhesion to the infant gut. Milk oligosaccharides reduce infectivity of a porcine rotavirus strain; however, the effects on human rotaviruses are less well understood.Objective: In this study, we determined the effect of specific and abundant milk oligosaccharides on the infectivity of 2 globally dominant human rotavirus strains.Methods: Four milk oligosaccharides-2'-fucosyllactose (2'FL), 3'-sialyllactose (3'SL), 6'-sialyllactose (6'SL), and galacto-oligosaccharides-were tested for their effects on the infectivity of human rotaviruses G1P[8] and G2P[4] through fluorescent focus assays on African green monkey kidney epithelial cells (MA104 cells). Oligosaccharides were added at different time points in the infectivity assays. Infections in the absence of oligosaccharides served as controls.Results: When compared with infections in the absence of glycans, all oligosaccharides substantially reduced the infectivity of both human rotavirus strains in vitro; however, virus strain-specific differences in effects were observed. Compared with control infections, the maximum reduction in G1P[8] infectivity was seen with 2'FL when added after the onset of infection (62% reduction, P < 0.01), whereas the maximum reduction in G2P[4] infectivity was seen with the mixture of 3'SL + 6'SL when added during infection (73% reduction, P < 0.01). The mixture of 3'SL + 6'SL at the same ratio as is present in breast milk was more potent in reducing G2P[4] infectivity (73% reduction, P < 0.01) than when compared with 3'SL (47% reduction) or 6'SL (40% reduction) individually. For all oligosaccharides the reduction in infectivity was mediated by an effect on the virus and not on the cells.Conclusions: Milk oligosaccharides reduce the infectivity of human rotaviruses in MA104 cells, primarily through an effect on the virus. Although breastfed infants are directly protected, the addition of specific

  15. Inhibition of human natural killer cell activity by Pseudomonas aeruginosa alkaline protease and elastase.

    PubMed Central

    Pedersen, B K; Kharazmi, A

    1987-01-01

    The present study was designed to examine the effect of Pseudomonas aeruginosa alkaline protease (AP) and elastase (Ela) on human natural killer (NK) cell activity in vitro. AP and Ela were found to inhibit NK cell function. Addition of alpha interferon and interleukin-2 did not abolish this inhibition of NK cell activity. Adhesion of effector to target cells was studied in a single-cell agarose assay of monocyte-depleted NK-cell-enriched cell populations. AP and Ela were shown to inhibit effector/target cell conjugate formation. Furthermore, AP and Ela inhibited the binding of the monoclonal antibody Leu-11, which reacts with the Fc receptor of NK cells. The inhibition of NK cell binding to the target cell by P. aeruginosa proteases is most likely due to proteolytic cleavage of the surface receptors involved in the binding of the effector cell to the target cell. PMID:3030937

  16. Vasoactive Intestinal Peptide Inhibits Human Small-Cell Lung Cancer Proliferation in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Maruno, Kaname; Absood, Afaf; Said, Sami I.

    1998-11-01

    Small-cell lung carcinoma (SCLC) is an aggressive, rapidly growing and metastasizing, and highly fatal neoplasm. We report that vasoactive intestinal peptide inhibits the proliferation of SCLC cells in culture and dramatically suppresses the growth of SCLC tumor-cell implants in athymic nude mice. In both cases, the inhibition was mediated apparently by a cAMP-dependent mechanism, because the inhibition was enhanced by the adenylate cyclase activator forskolin and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine in proportion to increases in intracellular cAMP levels, and the inhibition was abolished by selective inhibition of cAMP-dependent protein kinase. If confirmed in clinical trials, this antiproliferative action of vasoactive intestinal peptide may offer a new and promising means of suppressing SCLC in human subjects, without the toxic side effects of chemotherapeutic agents.

  17. Inhibition of human lanosterol synthase by the constituents of Colocasia esculenta (taro).

    PubMed

    Sakano, Yuichi; Mutsuga, Motoh; Tanaka, Rie; Suganuma, Hiroyuki; Inakuma, Takahiro; Toyoda, Masatake; Goda, Yukihiro; Shibuya, Masaaki; Ebizuka, Yutaka

    2005-02-01

    Ethanol extracts of lyophilized vegetables were tested for inhibition of human lanosterol synthase (hOSC) in order to find the compounds to suppress cholesterol biosynthesis. Of 130 samples tested, twelve samples showed significant inhibition. Among them, Colocasia esculenta (taro) showed the highest inhibition (55% inhibition at 300 microg/ml). Examination of activity variation among eight taro cultivars indicated that "Aichi-wase" and "Yatsugashira" had the most potent activity for hOSC inhibition. In order to identify the active constituent of taro, ethanol extracts of "Aichi-wase" were partitioned with hexane and aqueous methanol, and fractionated by silica gel column chromatography. Inhibitory activity was concentrated in two major active fractions. Further purification of these fractions by preparative HPLC gave three monogalactosyldiacylglycerols and five digalactosyldiacylglycerols as active compounds that showed 28 to 67% inhibitory activities at the concentration 300 microg/ml.

  18. Crystal structure of the thioesterase domain of human fatty acid synthase inhibited by orlistat

    SciTech Connect

    Pemble,C.; Johnson, L.; Kridel, S.; Lowther, W.

    2007-01-01

    Human fatty acid synthase (FAS) is uniquely expressed at high levels in many tumor types. Pharmacological inhibition of FAS therefore represents an important therapeutic opportunity. The drug Orlistat, which has been approved by the US Food and Drug Administration, inhibits FAS, induces tumor cell-specific apoptosis and inhibits the growth of prostate tumor xenografts. We determined the 2.3-{angstrom}-resolution crystal structure of the thioesterase domain of FAS inhibited by Orlistat. Orlistat was captured in the active sites of two thioesterase molecules as a stable acyl-enzyme intermediate and as the hydrolyzed product. The details of these interactions reveal the molecular basis for inhibition and suggest a mechanism for acyl-chain length discrimination during the FAS catalytic cycle. Our findings provide a foundation for the development of new cancer drugs that target FAS.

  19. Inhibition of human UDP-glucuronosyltransferase enzymes by lapatinib, pazopanib, regorafenib and sorafenib: Implications for hyperbilirubinemia.

    PubMed

    Miners, John O; Chau, Nuy; Rowland, Andrew; Burns, Kushari; McKinnon, Ross A; Mackenzie, Peter I; Tucker, Geoffrey T; Knights, Kathleen M; Kichenadasse, Ganessan

    2017-04-01

    Kinase inhibitors (KIs) are a rapidly expanding class of drugs used primarily for the treatment of cancer. Data relating to the inhibition of UDP-glucuronosyltransferase (UGT) enzymes by KIs is sparse. However, lapatinib (LAP), pazopanib (PAZ), regorafenib (REG) and sorafenib (SOR) have been implicated in the development of hyperbilirubinemia in patients. This study aimed to characterise the role of UGT1A1 inhibition in hyperbilirubinemia and assess the broader potential of these drugs to perpetrate drug-drug interactions arising from UGT enzyme inhibition. Twelve recombinant human UGTs from subfamilies 1A and 2B were screened for inhibition by LAP, PAZ, REG and SOR. IC50 values for the inhibition of all UGT1A enzymes, except UGT1A3 and UGT1A4, by the four KIs were <10μM. LAP, PAZ, REG and SOR inhibited UGT1A1-catalysed bilirubin glucuronidation with mean IC50 values ranging from 34nM (REG) to 3734nM (PAZ). Subsequent kinetic experiments confirmed that REG and SOR were very potent inhibitors of human liver microsomal β-estradiol glucuronidation, an established surrogate for bilirubin glucuronidation, with mean Ki values of 20 and 33nM, respectively. Ki values for LAP and PAZ were approximately 1- and 2-orders of magnitude higher than those for REG and SOR. REG and SOR were equipotent inhibitors of human liver microsomal UGT1A9 (mean Ki 678nM). REG and SOR are the most potent inhibitors of a human UGT enzyme identified to date. In vitro-in vivo extrapolation indicates that inhibition of UGT1A1 contributes significantly to the hyperbilirubinemia observed in patients treated with REG and SOR, but not with LAP and PAZ. Inhibition of other UGT1A1 substrates in vivo is likely.

  20. Inhibiting DNA-PKCS radiosensitizes human osteosarcoma cells.

    PubMed

    Mamo, Tewodros; Mladek, Ann C; Shogren, Kris L; Gustafson, Carl; Gupta, Shiv K; Riester, Scott M; Maran, Avudaiappan; Galindo, Mario; van Wijnen, Andre J; Sarkaria, Jann N; Yaszemski, Michael J

    2017-04-29

    Osteosarcoma survival rate has not improved over the past three decades, and the debilitating side effects of the surgical treatment suggest the need for alternative local control approaches. Radiotherapy is largely ineffective in osteosarcoma, indicating a potential role for radiosensitizers. Blocking DNA repair, particularly by inhibiting the catalytic subunit of DNA-dependent protein kinase (DNA-PKCS), is an attractive option for the radiosensitization of osteosarcoma. In this study, the expression of DNA-PKCS in osteosarcoma tissue specimens and cell lines was examined. Moreover, the small molecule DNA-PKCS inhibitor, KU60648, was investigated as a radiosensitizing strategy for osteosarcoma cells in vitro. DNA-PKCS was consistently expressed in the osteosarcoma tissue specimens and cell lines studied. Additionally, KU60648 effectively sensitized two of those osteosarcoma cell lines (143B cells by 1.5-fold and U2OS cells by 2.5-fold). KU60648 co-treatment also altered cell cycle distribution and enhanced DNA damage. Cell accumulation at the G2/M transition point increased by 55% and 45%, while the percentage of cells with >20 γH2AX foci were enhanced by 59% and 107% for 143B and U2OS cells, respectively. These results indicate that the DNA-PKCS inhibitor, KU60648, is a promising radiosensitizing agent for osteosarcoma. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Chlorogenic Acid Inhibits Human Platelet Activation and Thrombus Formation

    PubMed Central

    Fuentes, Eduardo; Caballero, Julio; Alarcón, Marcelo; Rojas, Armando; Palomo, Iván

    2014-01-01

    Background Chlorogenic acid is a potent phenolic antioxidant. However, its effect on platelet aggregation, a critical factor in arterial thrombosis, remains unclear. Consequently, chlorogenic acid-action mechanisms in preventing platelet activation and thrombus formation were examined. Methods and Results Chlorogenic acid in a dose-dependent manner (0.1 to 1 mmol/L) inhibited platelet secretion and aggregation induced by ADP, collagen, arachidonic acid and TRAP-6, and diminished platelet firm adhesion/aggregation and platelet-leukocyte interactions under flow conditions. At these concentrations chlorogenic acid significantly decreased platelet inflammatory mediators (sP-selectin, sCD40L, CCL5 and IL-1β) and increased intraplatelet cAMP levels/PKA activation. Interestingly, SQ22536 (an adenylate cyclase inhibitor) and ZM241385 (a potent A2A receptor antagonist) attenuated the antiplatelet effect of chlorogenic acid. Chlorogenic acid is compatible to the active site of the adenosine A2A receptor as revealed through molecular modeling. In addition, chlorogenic acid had a significantly lower effect on mouse bleeding time when compared to the same dose of aspirin. Conclusions Antiplatelet and antithrombotic effects of chlorogenic acid are associated with the A2A receptor/adenylate cyclase/cAMP/PKA signaling pathway. PMID:24598787

  2. SKI knockdown inhibits human melanoma tumor growth in vivo.

    PubMed

    Chen, Dahu; Lin, Qiushi; Box, Neil; Roop, Dennis; Ishii, Shunsuke; Matsuzaki, Koichi; Fan, Tao; Hornyak, Thomas J; Reed, Jon A; Stavnezer, Ed; Timchenko, Nikolai A; Medrano, Estela E

    2009-12-01

    The SKI protein represses the TGF-beta tumor suppressor pathway by associating with the Smad transcription factors. SKI is upregulated in human malignant melanoma tumors in a disease-progression manner and its overexpression promotes proliferation and migration of melanoma cells in vitro. The mechanisms by which SKI antagonizes TGF-beta signaling in vivo have not been fully elucidated. Here we show that human melanoma cells in which endogenous SKI expression was knocked down by RNAi produced minimal orthotopic tumor xenograft nodules that displayed low mitotic rate and prominent apoptosis. These minute tumors exhibited critical signatures of active TGF-beta signaling including high levels of nuclear Smad3 and p21(Waf-1), which are not found in the parental melanomas. To understand how SKI promotes tumor growth we used gain- and loss-of-function approaches and found that simultaneously to blocking the TGF-beta-growth inhibitory pathway, SKI promotes the switch of Smad3 from tumor suppression to oncogenesis by favoring phosphorylations of the Smad3 linker region in melanoma cells but not in normal human melanocytes. In this context, SKI is required for preventing TGF-beta-mediated downregulation of the oncogenic protein c-MYC, and for inducing the plasminogen activator inhibitor-1, a mediator of tumor growth and angiogenesis. Together, the results indicate that SKI exploits multiple regulatory levels of the TGF-beta pathway and its deficiency restores TGF-beta tumor suppressor and apoptotic activities in spite of the likely presence of oncogenic mutations in melanoma tumors.

  3. Malathion, carbofuran and paraquat inhibit Bungarus sindanus (krait) venom acetylcholinesterase and human serum butyrylcholinesterase in vitro.

    PubMed

    Ahmed, Mushtaq; Rocha, João Batista T; Mazzanti, Cinthia M; Morsch, André L B; Cargnelutti, Denise; Corrêa, Maísa; Loro, Vânia; Morsch, Vera Maria; Schetinger, Maria R C

    2007-05-01

    Carbofuran and malathion, well known pesticides, and paraquat, a world widely used herbicide, were tested on acetylcholinesterase (AChE) from Bungarus sindanus venom and butyrylcholinesterase (BChE) from human serum. The calculated IC(50 )values for inhibition of venom enzyme by malathion, carbofuran and paraquat were 2.5, 0.14, and 0.16 microM, respectively. The values for inhibition of serum butyrylcholinesterase (BChE) were 3.5, 0.09 and 0.18 microM, respectively. Analysis of kinetic data indicated that the inhibition caused by malathion, carbofuran and paraquat was mixed for venom AChE. For BChE from human serum, the inhibition caused by malathion and paraquat was mixed and for carbofuran it was uncompetitive. The present results suggest a commercial paraquat preparation (a popular herbicide) inhibits cholinesterases with similar or higher potency than classical pesticide inhibitors. Furthermore, this inhibition was observed both in human serum and snake venom, a newly studied source of AChE.

  4. Potent inhibition by star fruit of human cytochrome P450 3A (CYP3A) activity.

    PubMed

    Hidaka, Muneaki; Fujita, Ken-ichi; Ogikubo, Tetsuya; Yamasaki, Keishi; Iwakiri, Tomomi; Okumura, Manabu; Kodama, Hirofumi; Arimori, Kazuhiko

    2004-06-01

    There has been very limited information on the capacities of tropical fruits to inhibit human cytochrome P450 3A (CYP3A) activity. Thus, the inhibitory effects of tropical fruits on midazolam 1'-hydroxylase activity of CYP3A in human liver microsomes were evaluated. Eight tropical fruits such as common papaw, dragon fruit, kiwi fruit, mango, passion fruit, pomegranate, rambutan, and star fruit were tested. We also examined the inhibition of CYP3A activity by grapefruit (white) and Valencia orange as controls. The juice of star fruit showed the most potent inhibition of CYP3A. The addition of a star fruit juice (5.0%, v/v) resulted in the almost complete inhibition of midazolam 1'-hydroxylase activity (residual activity of 0.1%). In the case of grape-fruit, the residual activity was 14.7%. The inhibition depended on the amount of fruit juice added to the incubation mixture (0.2-6.0%, v/v). The elongation of the preincubation period of a juice from star fruit (1.25 or 2.5%, v/v) with the microsomal fraction did not alter the CYP3A inhibition, suggesting that the star fruit did not contain a mechanism-based inhibitor. Thus, we discovered filtered extracts of star fruit juice to be inhibitors of human CYP3A activity in vitro.

  5. The antifungal antibiotic, clotrimazole, inhibits Cl- secretion by polarized monolayers of human colonic epithelial cells.

    PubMed Central

    Rufo, P A; Jiang, L; Moe, S J; Brugnara, C; Alper, S L; Lencer, W I

    1996-01-01

    Clotrimazole (CLT) prevents dehydration of the human HbSS red cell through inhibition of Ca++-dependent (Gardos) K+ channels in vitro (1993. J. Clin Invest. 92:520-526.) and in patients (1996. J. Clin Invest. 97:1227-1234.). Basolateral membrane K+ channels of intestinal crypt epithelial cells also participate in secretagogue-stimulated Cl- secretion. We examined the ability of CLT to block intestinal Cl- secretion by inhibition of K+ transport. Cl- secretion was measured as short-circuit current (Isc) across monolayers of T84 cells. CLT reversibly inhibited Cl- secretory responses to both cAMP- and Ca2+-dependent agonists with IC50 values of approximately 5 microM. Onset of inhibition was more rapid when CLT was applied to the basolateral cell surface. Apical Cl- channel and basolateral NaK2Cl cotransporter activities were unaffected by CLT treatment as assessed by isotopic flux measurement. In contrast, CLT strongly inhibited basolateral 86Rb efflux. These data provide evidence that CLT reversibly inhibits Cl- secretion elicited by cAMP-, cGMP-, or Ca2+-dependent agonists in T84 cells. CLT acts distal to the generation of cAMP and Ca2+ signals, and appears to inhibit basolateral K+ channels directly. CLT and related drugs may serve as novel antidiarrheal agents in humans and animals. PMID:8903326

  6. Advanced Glycation End Products Inhibit the Proliferation of Human Umbilical Vein Endothelial Cells by Inhibiting Cathepsin D

    PubMed Central

    Li, Yuan; Chang, Ye; Ye, Ning; Dai, Dongxue; Chen, Yintao; Zhang, Naijin; Sun, Guozhe; Sun, Yingxian

    2017-01-01

    We aimed to investigate the effect of advanced glycation end products (AGEs) on the proliferation and migration ability of human umbilical vein endothelial cells (HUVECs). Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay, real-time cell analyzer and 5-Ethynyl-2′-deoxyuridine (EdU) staining. Cell migration was detected by wound-healing and transwell assay. AGEs significantly inhibited the proliferation and migration of HUVECs in a time-and dose-dependent way. Western blotting revealed that AGEs dramatically increased the expression of microtubule-associated protein 1 light chain 3 (LC3) II/I and p62. Immunofluorescence of p62 and acridine orange staining revealed that AGEs significantly increased the expression of p62 and the accumulation of autophagic vacuoles, respectively. Chloroquine (CQ) could further promote the expression of LC3 II/I and p62, increase the accumulation of autophagic vacuoles and promote cell injury induced by AGEs. In addition, AGEs reduced cathepsin D (CTSD) expression in a time-dependent way. Overexpression of wild-type CTSD significantly decreased the ratio of LC 3 II/I as well as p62 accumulation induced by AGEs, but overexpression of catalytically inactive mutant CTSD had no such effects. Only overexpression of wild-type CTSD could restore the proliferation of HUVECs inhibited by AGEs. However, overexpression of both wild-type CTSD and catalytically inactive mutant CTSD could promote the migration of HUVECs inhibited by AGEs. Collectively, our study found that AGEs inhibited the proliferation and migration in HUVECs and promoted autophagic flux, which in turn played a protective role against AGEs-induced cell injury. CTSD, in need of its catalytic activity, may promote proliferation in AGEs-treated HUVECs independent of the autophagy-lysosome pathway. Meanwhile, CTSD could improve the migration of AGEs-treated HUVECs regardless of its enzymatic activity. PMID:28218663

  7. Advanced Glycation End Products Inhibit the Proliferation of Human Umbilical Vein Endothelial Cells by Inhibiting Cathepsin D.

    PubMed

    Li, Yuan; Chang, Ye; Ye, Ning; Dai, Dongxue; Chen, Yintao; Zhang, Naijin; Sun, Guozhe; Sun, Yingxian

    2017-02-17

    We aimed to investigate the effect of advanced glycation end products (AGEs) on the proliferation and migration ability of human umbilical vein endothelial cells (HUVECs). Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay, real-time cell analyzer and 5-Ethynyl-2'-deoxyuridine (EdU) staining. Cell migration was detected by wound-healing and transwell assay. AGEs significantly inhibited the proliferation and migration of HUVECs in a time-and dose-dependent way. Western blotting revealed that AGEs dramatically increased the expression of microtubule-associated protein 1 light chain 3 (LC3) II/I and p62. Immunofluorescence of p62 and acridine orange staining revealed that AGEs significantly increased the expression of p62 and the accumulation of autophagic vacuoles, respectively. Chloroquine (CQ) could further promote the expression of LC3 II/I and p62, increase the accumulation of autophagic vacuoles and promote cell injury induced by AGEs. In addition, AGEs reduced cathepsin D (CTSD) expression in a time-dependent way. Overexpression of wild-type CTSD significantly decreased the ratio of LC 3 II/I as well as p62 accumulation induced by AGEs, but overexpression of catalytically inactive mutant CTSD had no such effects. Only overexpression of wild-type CTSD could restore the proliferation of HUVECs inhibited by AGEs. However, overexpression of both wild-type CTSD and catalytically inactive mutant CTSD could promote the migration of HUVECs inhibited by AGEs. Collectively, our study found that AGEs inhibited the proliferation and migration in HUVECs and promoted autophagic flux, which in turn played a protective role against AGEs-induced cell injury. CTSD, in need of its catalytic activity, may promote proliferation in AGEs-treated HUVECs independent of the autophagy-lysosome pathway. Meanwhile, CTSD could improve the migration of AGEs-treated HUVECs regardless of its enzymatic activity.

  8. Phentolamine inhibits angiogenesis in vitro: Suppression of proliferation migration and differentiation of human endothelial cells.

    PubMed

    Pan, Liangli; Liu, Chenyang; Kong, Yanan; Piao, Zhengguo; Cheng, Biao

    2016-06-16

    It is widely known that the β-adrenergic receptor (AR) blocker (propranolol) inhibits human endothelial cell (EC) angiogenesis in vitro, but how the α-AR antagonist (phentolamine) affects human EC angiogenesis has not yet been studied. Here, we show for the first time that both human dermal microvascular ECs (HDMECs) and human brain microvascular ECs (HBMECs) express α-ARs. Moreover, our results indicate that phentolamine inhibits the proliferation, migration, and tubulogenesis of HDMECs and HBMECs. Finally, VEGFR-2 and Ang1/2 expression of HDMECs was suppressed by phentolamine. Together, these results indicate that phentolamine impairs several critical events of neovascularization, and α-ARs, as well as the VEGF/VEGFR-2 and Ang/Tie-2 signaling pathways, may be involved in these processes. Our results suggest a novel therapeutic strategy for the use of α-blockers in the treatment of human angiogenesis-dependent diseases.

  9. Inhibition of viral reverse transcriptase and human sperm DNA polymerase by anti-sperm antibodies.

    PubMed Central

    Witkin, S S; Higgins, P J; Bendich, A

    1978-01-01

    The IgG fraction of serum from a rabbit immunized with detergent-prepared human sperm nuclei inhibited the DNA polymerase activities in human sperm and seminal fluid as well as the partially purified reverse transcriptase of the baboon endogenous type-C retrovirus (BEV). The analogous enzymes from lysates of oncogenic type-C viruses was unaffected. IgG from the serum of individual partners from infertile marriages similarly inhibited both purified BEV reverse transcriptase and human sperm DNA polymerase, but not a DNA polymerase isolated from human prostatic fluid. The data suggest that BEV reverse transcriptase and the human sperm DNA polymerase are antigenically related. Furthermore, the sperm appears to be auto-antigenic and the antibodies thus formed may be capable of interfering with reproductive success. PMID:82498

  10. Inhibition of human arginase I by substrate and product analogues

    SciTech Connect

    Di Costanzo, Luigi; Ilies, Monica; Thorn, Katherine J.; Christianson, David W.

    2010-06-21

    Human arginase I is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of l-arginine to generate l-ornithine and urea. We demonstrate that N-hydroxy-l-arginine (NOHA) binds to this enzyme with K{sub d} = 3.6 {micro}M, and nor-N-hydroxy-l-arginine (nor-NOHA) binds with K{sub d} = 517 nM (surface plasmon resonance) or K{sub d} {approx} 50 nM (isothermal titration calorimetry). Crystals of human arginase I complexed with NOHA and nor-NOHA afford 2.04 and 1.55 {angstrom} resolution structures, respectively, which are significantly improved in comparison with previously-determined structures of the corresponding complexes with rat arginase I. Higher resolution structures clarify the binding interactions of the inhibitors. Finally, the crystal structure of the complex with l-lysine (K{sub d} = 13 {micro}M) is reported at 1.90 {angstrom} resolution. This structure confirms the importance of hydrogen bond interactions with inhibitor {alpha}-carboxylate and {alpha}-amino groups as key specificity determinants of amino acid recognition in the arginase active site.

  11. Inhibition of Human Arginase I by Substrate adn Product Analogues

    SciTech Connect

    L Di Costanzo; M Ilies; K Thorn; D Christianson

    2011-12-31

    Human arginase I is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of L-arginine to generate L-ornithine and urea. We demonstrate that N-hydroxy-L-arginine (NOHA) binds to this enzyme with K(d)=3.6 microM, and nor-N-hydroxy-L-arginine (nor-NOHA) binds with K(d)=517 nM (surface plasmon resonance) or K(d) approximately 50 nM (isothermal titration calorimetry). Crystals of human arginase I complexed with NOHA and nor-NOHA afford 2.04 and 1.55 A resolution structures, respectively, which are significantly improved in comparison with previously-determined structures of the corresponding complexes with rat arginase I. Higher resolution structures clarify the binding interactions of the inhibitors. Finally, the crystal structure of the complex with L-lysine (K(d)=13 microM) is reported at 1.90 A resolution. This structure confirms the importance of hydrogen bond interactions with inhibitor alpha-carboxylate and alpha-amino groups as key specificity determinants of amino acid recognition in the arginase active site.

  12. The structure and inhibition of human diamine oxidase†,‡

    PubMed Central

    McGrath, Aaron P; Hilmer, Kimberly M; Collyer, Charles A; Shepard, Eric M; Elmore, Bradley O.; Brown, Doreen E; Dooley, David M; Guss, J Mitchell

    2009-01-01

    Humans have three functioning genes that code for copper-containing amine oxidases. The product of the AOC1 gene is a so-called diamine oxidase (hDAO), named for its substrate preference for diamines, particularly histamine. hDAO has been cloned and expressed in insect cells and the structure of the native enzyme determined by X-ray crystallography to a resolution of 1.8 Å. The homodimeric structure has the archetypal amine oxidase fold. Two active sites, one in each subunit, are characterized by the presence of a copper ion and a topaquinone residue formed by the post-translational modification of a tyrosine. Although hDAO shares 37.9 % sequence identity with another human copper amine oxidase, semicarbazide sensitive amine oxidase or vascular adhesion protein-1, its substrate binding pocket and entry channel are distinctly different in accord with the different substrate specificities. The structures of two inhibitor complexes of hDAO, berenil and pentamidine, have been refined to resolutions of 2.1 Å and 2.2 Å, respectively. They bind non-covalently in the active site channel. The inhibitor binding suggests that an aspartic acid residue, conserved in all diamine oxidases but absent from other amine oxidases, is responsible for the diamine specificity by interacting with the second amino group of preferred diamine substrates. PMID:19764817

  13. Polyhexanide and hydrogen peroxide inhibit proteoglycan synthesis of human chondrocytes.

    PubMed

    Röhner, Eric; Hoff, Paula; Winkler, Tobias; von Roth, Philipp; Seeger, Jörn Bengt; Perka, Carsten; Matziolis, Georg

    2011-03-01

    The use of local antiseptics is a common method in septic joint surgery. We tested polyhexanide and hydrogen peroxide, two of the most frequently used antiseptics with high efficacy and low toxicity. The purpose of this study was to evaluate the effects of both antiseptics on the extracellular cartilaginous matrix synthesis of human chondrocytes. Chondrocytes were isolated from donated human knee joints, embedded in alginate beads, and incubated for 10 and 30 minutes with polyhexanide (0.04%), hydrogen peroxide (3%), or phosphate-buffered saline (PBS) for control. Cartilaginous matrix production was quantified through light microscopic analysis of Alcian blue staining. Cell number and morphology were detected by histological analysis. Chondrocytes showed a decreased intensity of blue colouring after antiseptic treatment versus PBS. In contrast to that, neither the cell number per view field nor the cell morphology differed between the groups. Polyhexanide has more toxic potential than hydrogen peroxide. Based on the fact that the cell number and morphology was not altered by the substances at the examined concentrations, the lower intensity of Alcian blue staining of treated chondrocytes indicates a decreased cartilage-specific matrix synthesis by polyhexanide more than by hydrogen peroxide and control.

  14. The pain inhibiting pain effect: an electrophysiological study in humans.

    PubMed

    Reinert, A; Treede, R; Bromm, B

    2000-04-17

    This study examines the counterirritation phenomenon of experimental pain in human subjects. Phasic pain induced by intracutaneous electrical stimuli was simultaneously applied with tonic pain induced by ischemic muscle work. Pain ratings, spontaneous EEG and evoked potentials were measured. We found a significant reduction of phasic pain ratings during and 10 min after tonic pain. The late somatosensory evoked potentials as neurophysiological correlates of phasic pain sensation were attenuated until 20 min after tonic pain offset. The extent of phasic pain relief due to concomitant tonic pain was small but significant, comparable to the effect of a regular systemic dose of a narco-analgesic drug in this experimental pain model. On the other hand, no modulations in the late components of the auditory evoked potential and the power spectrum of the spontaneous EEG were observed. These variables reflect the attention and vigilance of the subject and are well-known to be affected by opioids. The only exception was an increase of beta power, which might reflect hyperarousal during tonic pain. These results support the suggestion, that the analgesic effect of heterotopic noxious stimulation in humans is based on the activation of a specific inhibitory pain control system. Systemic release of endogenous opioids is unlikely to be involved, because the typical effects of opioids on the EEG were not observed.

  15. Caspase Induction and BCL2 Inhibition in Human Adipose Tissue

    PubMed Central

    Tinahones, Francisco José; Coín Aragüez, Leticia; Murri, Mora; Oliva Olivera, Wilfredo; Mayas Torres, María Dolores; Barbarroja, Nuria; Gomez Huelgas, Ricardo; Malagón, Maria M.; El Bekay, Rajaa

    2013-01-01

    OBJECTIVE Cell death determines the onset of obesity and associated insulin resistance. Here, we analyze the relationship among obesity, adipose tissue apoptosis, and insulin signaling. RESEARCH DESIGN AND METHODS The expression levels of initiator (CASP8/9) and effector (CASP3/7) caspases as well as antiapoptotic B-cell lymphoma (BCL)2 and inflammatory markers were assessed in visceral (VAT) and subcutaneous (SAT) adipose tissue from patients with different degrees of obesity and without insulin resistance or diabetes. Adipose tissue explants from lean subjects were cultured with TNF-α or IL-6, and the expression of apoptotic and insulin signaling components was analyzed and compared with basal expression levels in morbidly obese subjects. RESULTS SAT and VAT exhibited increased CASP3/7 and CASP8/9 expression levels and decreased BCL2 expression with BMI increase. These changes were accompanied by increased inflammatory cytokine mRNA levels and macrophage infiltration markers. In obese subjects, CASP3/7 activation and BCL2 downregulation correlated with the IRS-1/2–expression levels. Expression levels of caspases, BCL2, p21, p53, IRS-1/2, GLUT4, protein tyrosine phosphatase 1B, and leukocyte antigen-related phosphatase in TNF-α– or IL-6–treated explants from lean subjects were comparable with those found in adipose tissue samples from morbidly obese subjects. These insulin component expression levels were reverted with CASP3/7 inhibition in these TNF-α– or IL-6–treated explants. CONCLUSIONS Body fat mass increase is associated with CASP3/7 and BCL2 expression in adipose tissue. Moreover, this proapoptotic state correlated with insulin signaling, suggesting its potential contribution to the development of insulin resistance. PMID:23193206

  16. Kinetics of the inhibition of human renin by an inhibitor containing a hydroxyethylene dipeptide isostere

    SciTech Connect

    Kati, W.M.; Pals, D.T.; Thaisrivongs, S.

    1987-12-01

    The authors have studied the inhibition of both human and hog renins by compound 1 (Boc-Pro-Phe-N/sup ..cap alpha../-MeHis-LeuPsi(CHOHCH/sub 2/)Val-Ile-(aminomethyl) pyridine) using kinetics. The inhibition of human renin was shown to be time dependent and followed a minimal two-step mechanism. A loosely bound EI complex was formed rapidly with a dissociation constant, K/sub I/, of 12 nM. A second EI complex was slowly formed and was found to be 64-fold more strongly bound with an overall K/sub I/ of 0.19 nM. The inhibition of human renin was shown to be competitive by both initial and final steady-state velocities. Compound 1 was also shown to be a competitive inhibitor of hog renin with a K/sub I/ of 12 nM, but no evidence for time-dependent inhibition was detected. The differences in overall K/sub I/ and inhibition kinetics may be a consequence of the similarities in structure between 1 and human angiotensinogen, which was assayed by a radioimmunoassay procedure.

  17. Identifying human milk glycans that inhibit norovirus binding using surface plasmon resonance

    PubMed Central

    Shang, Jing; Piskarev, Vladimir E; Xia, Ming; Huang, Pengwei; Jiang, Xi; Likhosherstov, Leonid M; Novikova, Olga S; Newburg, David S; Ratner, Daniel M

    2013-01-01

    Human milk glycans inhibit binding between norovirus and its host glycan receptor; such competitive inhibition by human milk glycans is associated with a reduced risk of infection. The relationship between the presence of specific structural motifs in the human milk glycan and its ability to inhibit binding by specific norovirus strains requires facile, accurate and miniaturized-binding assays. Toward this end, a high-throughput biosensor platform was developed based on surface plasmon resonance imaging (SPRi) of glycan microarrays. The SPRi was validated, and its utility was tested, by measuring binding specificities between defined human milk glycan epitopes and the capsids of two common norovirus strains, VA387 and Norwalk. Human milk oligosaccharide (HMOS)-based neoglycoconjugates, including chemically derived neoglycoproteins and oligosaccharide-glycine derivatives, were used to represent polyvalent glycoconjugates and monovalent oligosaccharides, respectively, in human milk. SPRi binding results established that the glycan motifs that bind norovirus capsids depend upon strain; VA387 capsid interacts with two neoglycoproteins, whereas Norwalk capsid binds to a different set of HMOS motifs in the form of both polyvalent neoglycoproteins and monovalent oligosaccharides. SPRi competitive binding assays further demonstrated that specific norovirus-binding glycans are able to inhibit norovirus capsid binding to their host receptors. A polyvalent neoglycoconjugate with clustered carbohydrate moieties is required for the inhibition of VA387 capsid binding to host receptor glycans, whereas both monovalent oligosaccharides and polyvalent neoglycoconjugates are able to inhibit Norwalk capsid binding to its host receptor. Binding of HMOS and HMOS-based neoglycoconjugates to norovirus capsids depends upon the specific strain characteristics, implying that HMOS and their polyvalent derivatives are potential anti-adhesive agents for norovirus prophylaxis. PMID:24026239

  18. Identifying human milk glycans that inhibit norovirus binding using surface plasmon resonance.

    PubMed

    Shang, Jing; Piskarev, Vladimir E; Xia, Ming; Huang, Pengwei; Jiang, Xi; Likhosherstov, Leonid M; Novikova, Olga S; Newburg, David S; Ratner, Daniel M

    2013-12-01

    Human milk glycans inhibit binding between norovirus and its host glycan receptor; such competitive inhibition by human milk glycans is associated with a reduced risk of infection. The relationship between the presence of specific structural motifs in the human milk glycan and its ability to inhibit binding by specific norovirus strains requires facile, accurate and miniaturized-binding assays. Toward this end, a high-throughput biosensor platform was developed based on surface plasmon resonance imaging (SPRi) of glycan microarrays. The SPRi was validated, and its utility was tested, by measuring binding specificities between defined human milk glycan epitopes and the capsids of two common norovirus strains, VA387 and Norwalk. Human milk oligosaccharide (HMOS)-based neoglycoconjugates, including chemically derived neoglycoproteins and oligosaccharide-glycine derivatives, were used to represent polyvalent glycoconjugates and monovalent oligosaccharides, respectively, in human milk. SPRi binding results established that the glycan motifs that bind norovirus capsids depend upon strain; VA387 capsid interacts with two neoglycoproteins, whereas Norwalk capsid binds to a different set of HMOS motifs in the form of both polyvalent neoglycoproteins and monovalent oligosaccharides. SPRi competitive binding assays further demonstrated that specific norovirus-binding glycans are able to inhibit norovirus capsid binding to their host receptors. A polyvalent neoglycoconjugate with clustered carbohydrate moieties is required for the inhibition of VA387 capsid binding to host receptor glycans, whereas both monovalent oligosaccharides and polyvalent neoglycoconjugates are able to inhibit Norwalk capsid binding to its host receptor. Binding of HMOS and HMOS-based neoglycoconjugates to norovirus capsids depends upon the specific strain characteristics, implying that HMOS and their polyvalent derivatives are potential anti-adhesive agents for norovirus prophylaxis.

  19. The structural basis of the inhibition of human glycosidases by castanospermine analogues.

    PubMed Central

    Winchester, B G; Cenci di Bello, I; Richardson, A C; Nash, R J; Fellows, L E; Ramsden, N G; Fleet, G

    1990-01-01

    A series of epimers and deoxy derivatives of castanospermine has been synthesized to investigate the contribution of the different chiral centres to the specificity and potency of inhibition of human liver glycosidases. Castanospermine inhibits all forms of alpha- and beta-D-glucosidases, but alteration to any of the five chiral centres in castanospermine markedly decreases the inhibition. 6-Epicastanospermine, which is related to D-pyranomannose in the same way as castanospermine is to D-pyranoglucose, does not inhibit lysosomal (acidic) alpha-mannosidase, but is a good inhibitor of the cytosolic or neutral alpha-mannosidase. Conversely, 1-deoxy-6-epicastanospermine inhibits acidic alpha-mannosidase strongly, but not the neutral alpha-mannosidase. An explanation of this different inhibition based on preferential recognition of different configurations of mannose by the different forms of alpha-mannosidase is postulated. All derivatives of 6-epicastanospermine also have the minimum structural feature for the inhibition of alpha-L-fucosidase, but those with a beta-anomeric substituent do not inhibit the enzyme, or do so very weakly. 1-Deoxy-6,8a-diepicastanospermine, which has four chiral centres identical with alpha-L-fucose, is, however, a potent inhibitor of alpha-L-fucosidase (Ki 1.3 microM). PMID:2115770

  20. Determining Cysteines Available for Covalent Inhibition Across the Human Kinome.

    PubMed

    Zhao, Zheng; Liu, Qingsong; Bliven, Spencer; Xie, Lei; Bourne, Philip E

    2017-04-13

    Covalently bound protein kinase inhibitors have been frequently designed to target noncatalytic cysteines at the ATP binding site. Thus, it is important to know if a given cysteine can form a covalent bond. Here we combine a function-site interaction fingerprint method and DFT calculations to determine the potential of cysteines to form a covalent interaction with an inhibitor. By harnessing the human structural kinome, a comprehensive structure-based binding site cysteine data set was assembled. The orientation of the cysteine thiol group indicates which cysteines can potentially form covalent bonds. These covalent inhibitor easy-available cysteines are located within five regions: P-loop, roof of pocket, front pocket, catalytic-2 of the catalytic loop, and DFG-3 close to the DFG peptide. In an independent test set these cysteines covered 95% of covalent kinase inhibitors. This study provides new insights into cysteine reactivity and preference which is important for the prospective development of covalent kinase inhibitors.

  1. Diterpenoids from Tetraclinis articulata that inhibit various human leukocyte functions.

    PubMed

    Barrero, Alejandro F; Quílez del Moral, José F; Lucas, Rut; Payá, Miguel; Akssira, Mohamed; Akaad, Said; Mellouki, Fouad

    2003-06-01

    Ten new compounds, eight of them pimarane derivatives (1-8), together with a menthane dimer (9) and a totarane diterpenoid (10), were isolated from the leaves and wood of Tetraclinis articulata. The structures of 1-10 were established by using spectroscopic techniques, including 2D NMR spectra. Pimaranes 1-5 were found to possess an unusual cis interannular union of the B and C rings, which, from a biogenetic perspective, could be derived from the hydration of a carbocation at C-8. Compounds 4-6 and a mixture of 7 and 11 modulated different human leukocyte functions at a concentration of 10 microM, mainly the degranulation process measured as myeloperoxidase release and, to a lesser extent, the superoxide production measured by chemiluminescence.

  2. Evidence for substrate-dependent inhibition profiles for human liver aldehyde oxidase.

    PubMed

    Barr, John T; Jones, Jeffrey P

    2013-01-01

    The goal of this study was to provide a reasonable assessment of how probe substrate selection may impact the results of in vitro aldehyde oxidase (AO) inhibition experiments. Here, we used a previously studied set of seven known AO inhibitors to probe the inhibition profile of a pharmacologically relevant substrate N-[(2-dimethylamino)ethyl]acridine-4-carboxamide (DACA). DACA oxidation in human liver cytosol was characterized with a measured V(max) of 2.3 ± 0.08 nmol product · min(-1) · mg(-1) and a K(m) of 6.3 ± 0.8 µM. The K(ii) and K(is) values describing the inhibition of DACA oxidation by the panel of seven inhibitors were tabulated and compared with previous findings with phthalazine as the substrate. In every case, the inhibition profile shifted to a much less uncompetitive mode of inhibition for DACA relative to phthalazine. With the exception of one inhibitor, raloxifene, this change in inhibition profile seems to be a result of a decrease in the uncompetitive mode of inhibition (an affected K(ii) value), whereas the competitive mode (K(is)) seems to be relatively consistent between substrates. Raloxifene was found to inhibit competitively when using DACA as a probe, and a previous report showed that raloxifene inhibited uncompetitively with other substrates. The relevance of these data to the mechanistic understanding of aldehyde oxidase inhibition and potential implications on drug-drug interactions is discussed. Overall, it appears that the choice in substrate may be critical when conducting mechanistic inhibition or in vitro drug-drug interactions prediction studies with AO.

  3. Evidence for Substrate-Dependent Inhibition Profiles for Human Liver Aldehyde Oxidase

    PubMed Central

    Barr, John T.

    2013-01-01

    The goal of this study was to provide a reasonable assessment of how probe substrate selection may impact the results of in vitro aldehyde oxidase (AO) inhibition experiments. Here, we used a previously studied set of seven known AO inhibitors to probe the inhibition profile of a pharmacologically relevant substrate N-[(2-dimethylamino)ethyl]acridine-4-carboxamide (DACA). DACA oxidation in human liver cytosol was characterized with a measured Vmax of 2.3 ± 0.08 nmol product · min−1 · mg−1 and a Km of 6.3 ± 0.8 µM. The Kii and Kis values describing the inhibition of DACA oxidation by the panel of seven inhibitors were tabulated and compared with previous findings with phthalazine as the substrate. In every case, the inhibition profile shifted to a much less uncompetitive mode of inhibition for DACA relative to phthalazine. With the exception of one inhibitor, raloxifene, this change in inhibition profile seems to be a result of a decrease in the uncompetitive mode of inhibition (an affected Kii value), whereas the competitive mode (Kis) seems to be relatively consistent between substrates. Raloxifene was found to inhibit competitively when using DACA as a probe, and a previous report showed that raloxifene inhibited uncompetitively with other substrates. The relevance of these data to the mechanistic understanding of aldehyde oxidase inhibition and potential implications on drug-drug interactions is discussed. Overall, it appears that the choice in substrate may be critical when conducting mechanistic inhibition or in vitro drug-drug interactions prediction studies with AO PMID:22996261

  4. Suppression of autophagy augments the radiosensitizing effects of STAT3 inhibition on human glioma cells

    SciTech Connect

    Yuan, Xiaopeng; Du, Jie; Hua, Song; Zhang, Haowen; Gu, Cheng; Wang, Jie; Yang, Lei; Huang, Jianfeng; Yu, Jiahua Liu, Fenju

    2015-01-15

    Radiotherapy is an essential component of the standard therapy for newly diagnosed glioblastoma. To increase the radiosensitivity of glioma cells is a feasible solution to improve the therapeutic effects. It has been suggested that inhibition of signal transducer and activator of transcription 3 (STAT3) can radiosensitize glioma cells, probably via the activation of mitochondrial apoptotic pathway. In this study, human malignant glioma cells, U251 and A172, were treated with an STAT3 inhibitor, WP1066, or a short hairpin RNA plasmid targeting STAT3 to suppress the activation of STAT3 signaling. The radiosensitizing effects of STAT3 inhibition were confirmed in glioma cells. Intriguingly, combination of ionizing radiation exposure and STAT3 inhibition triggered a pronounced increase of autophagy flux. To explore the role of autophagy, glioma cells were treated with 3-methyladenine or siRNA for autophagy-related gene 5, and it was demonstrated that inhibition of autophagy further strengthened the radiosensitizing effects of STAT3 inhibition. Accordingly, more apoptotic cells were induced by the dual inhibition of autophagy and STAT3 signaling. In conclusion, our data revealed a protective role of autophagy in the radiosensitizing effects of STAT3 inhibition, and inhibition of both autophagy and STAT3 might be a potential therapeutic strategy to increase the radiosensitivity of glioma cells. - Highlights: • Inactivation of STAT3 signaling radiosensitizes malignant glioma cells. • STAT3 inhibition triggers a significant increase of autophagy flux induced by ionizing radiation in glioma cells. • Suppression of autophagy further strengthens the radiosensitizing effects of STAT3 inhibition in glioma cells. • Dual inhibition of autophagy and STAT3 induce massive apoptotic cells upon exposure to ionizing radiation.

  5. Human Neutralizing Monoclonal Antibody Inhibition of Middle East Respiratory Syndrome Coronavirus Replication in the Common Marmoset.

    PubMed

    Chen, Zhe; Bao, Linlin; Chen, Cong; Zou, Tingting; Xue, Ying; Li, Fengdi; Lv, Qi; Gu, Songzhi; Gao, Xiaopan; Cui, Sheng; Wang, Jianmin; Qin, Chuan; Jin, Qi

    2017-06-15

    Middle East respiratory syndrome coronavirus (MERS-CoV) infection in humans is highly lethal, with a fatality rate of 35%. New prophylactic and therapeutic strategies to combat human infections are urgently needed. We isolated a fully human neutralizing antibody, MCA1, from a human survivor. The antibody recognizes the receptor-binding domain of MERS-CoV S glycoprotein and interferes with the interaction between viral S and the human cellular receptor human dipeptidyl peptidase 4 (DPP4). To our knowledge, this study is the first to report a human neutralizing monoclonal antibody that completely inhibits MERS-CoV replication in common marmosets. Monotherapy with MCA1 represents a potential alternative treatment for human infections with MERS-CoV worthy of evaluation in clinical settings. © Crown copyright 2017.

  6. Quercetin Inhibits Cell Migration and Invasion in Human Osteosarcoma Cells.

    PubMed

    Lan, Haifeng; Hong, Wei; Fan, Pan; Qian, Dongyang; Zhu, Jianwei; Bai, Bo

    2017-09-21

    Osteosarcoma is a malignant tumor associated with high mortality; however, no effective therapies for the disease have been developed. Several studies have focused on elucidating the pathogenesis of osteosarcoma and have aimed to develop novel therapies for the disease. Quercetin is a vital dietary flavonoid that has been shown to have a variety of anticancer effects, as it induces cell cycle arrest, apoptosis, and differentiation and is involved in cell adhesion, metastasis and angiogenesis. Herein, we aimed to investigate the effects of quercetin on osteosarcoma migration and invasion in vitro and in vivo and to explore the molecular mechanisms underlying its effects on osteosarcoma migration and invasion. Cell viability, cell cycle activity and cell apoptosis were measured using CCK-8 assay and flow cytometry, and cell migration and invasion were evaluated by wound healing and transwell assays, respectively. The mRNA and protein expression levels of several proteins of interest were assessed by real-time quantitative PCR and western blotting, respectively. Moreover, a nude mouse model of human osteosarcoma lung metastasis was established to assess the anti-metastatic effects of quercetin in vivo. We noted no significant differences in cell cycle activity and apoptosis between HOS and MG63 cells and control cells. Treatment with quercetin significantly attenuated cell migration and invasion in HOS and MG63 cells compared with treatment with control medium. Moreover HIF-1α, VEGF, MMP2, and MMP9 mRNA and protein expression levels were significantly downregulated in HOS cells treated with quercetin compared with HOS cells treated with controls. Additionally, treatment with quercetin attenuated metastatic lung tumor formation and growth in the nude mouse model of osteosarcoma compared with treatment with controls. Our findings regarding the inhibitory effects of quercetin on cell migration and invasion suggest that quercetin may have potential as a therapy for human

  7. HIV-1 vpr inhibits cytokinesis in human proximal tubule cells

    PubMed Central

    Rosenstiel, Paul; Gruosso, Tina; Letourneau, Audrey; Chan, Justin; LeBlanc, Amanda; Husain, Mohammad; Najfeld, Vesna; Planelles, Vicente; D’Agati, Vivette; Klotman, Mary; Klotman, Paul E.

    2014-01-01

    HIV associated nephropathy (HIVAN) afflicts an estimated 1–3 million people worldwide and is a major cause of morbidity and mortality. Murine transgenic models have demonstrated that expression of HIV-1 genes in kidney cells results in characteristic HIVAN pathology: collapsing FSGS and microcystic tubular disease. While we have gained significant understanding of the podocyte disease, less is known about the tubular epithelial responses to infection. HIV-1 vpr plays an important role in the FSGS of HIVAN particularly in association with nef expression in podocytes. In addition, Vpr is reported to exacerbate tubular pathology. Therefore, we explored the effect of vpr expression on renal tubular epithelial cell function. Proximal tubule epithelial cells (PTEC) were transduced in vitro using a pseudotyped lentivirus vector carrying HIV-1 vpr and control genes. HIV-1 vpr expression in cultured PTECs impaired cytokinesis causing cell enlargement and multinucleation. Because the in vitro phenotype was so profound, we re-examined the HIVAN murine model and human HIVAN biopsies to see if similar changes could be seen in vivo. Surprisingly, both the transgenic murine HIVAN model and human HIVAN biopsies showed abundant hypertrophic tubule cells consistent with the in vitro findings. The extent of the tubular cell hypertrophy was particularly impressive and represents a previously unappreciated aspect of the disease. Additionally, multinucleated tubular cells were identified in the murine HIVAN model and increased chromosome number was detected in tubular cells in HIVAN biopsies. This study provides evidence of a new clinical phenotype in HIVAN that may result from Vpr’s ability to impair cytokinesis. PMID:18614999

  8. Effect of local acetylcholinesterase inhibition on sweat rate in humans

    NASA Technical Reports Server (NTRS)

    Shibasaki, M.; Crandall, C. G.

    2001-01-01

    ACh is the neurotransmitter responsible for increasing sweat rate (SR) in humans. Because ACh is rapidly hydrolyzed by acetylcholinesterase (AChE), it is possible that AChE contributes to the modulation of SR. Thus the primary purpose of this project was to identify whether AChE around human sweat glands is capable of modulating SR during local application of various concentrations of ACh in vivo, as well as during a heat stress. In seven subjects, two microdialysis probes were placed in the intradermal space of the forearm. One probe was perfused with the AChE inhibitor neostigmine (10 microM); the adjacent membrane was perfused with the vehicle (Ringer solution). SR over both membranes was monitored via capacitance hygrometry during microdialysis administration of various concentrations of ACh (1 x 10(-7)-2 M) and during whole body heating. SR was significantly greater at the neostigmine-treated site than at the control site during administration of lower concentrations of ACh (1 x 10(-7)-1 x 10(-3) M, P < 0.05), but not during administration of higher concentrations of ACh (1 x 10(-2)-2 M, P > 0.05). Moreover, the core temperature threshold for the onset of sweating at the neostigmine-treated site was significantly reduced relative to that at the control site. However, no differences in SR were observed between sites after 35 min of whole body heating. These results suggest that AChE is capable of modulating SR when ACh concentrations are low to moderate (i.e., when sudomotor activity is low) but is less effective in governing SR after SR has increased substantially.

  9. Effect of local acetylcholinesterase inhibition on sweat rate in humans

    NASA Technical Reports Server (NTRS)

    Shibasaki, M.; Crandall, C. G.

    2001-01-01

    ACh is the neurotransmitter responsible for increasing sweat rate (SR) in humans. Because ACh is rapidly hydrolyzed by acetylcholinesterase (AChE), it is possible that AChE contributes to the modulation of SR. Thus the primary purpose of this project was to identify whether AChE around human sweat glands is capable of modulating SR during local application of various concentrations of ACh in vivo, as well as during a heat stress. In seven subjects, two microdialysis probes were placed in the intradermal space of the forearm. One probe was perfused with the AChE inhibitor neostigmine (10 microM); the adjacent membrane was perfused with the vehicle (Ringer solution). SR over both membranes was monitored via capacitance hygrometry during microdialysis administration of various concentrations of ACh (1 x 10(-7)-2 M) and during whole body heating. SR was significantly greater at the neostigmine-treated site than at the control site during administration of lower concentrations of ACh (1 x 10(-7)-1 x 10(-3) M, P < 0.05), but not during administration of higher concentrations of ACh (1 x 10(-2)-2 M, P > 0.05). Moreover, the core temperature threshold for the onset of sweating at the neostigmine-treated site was significantly reduced relative to that at the control site. However, no differences in SR were observed between sites after 35 min of whole body heating. These results suggest that AChE is capable of modulating SR when ACh concentrations are low to moderate (i.e., when sudomotor activity is low) but is less effective in governing SR after SR has increased substantially.

  10. In vitro growth inhibition of human cancer cells by novel honokiol analogs

    PubMed Central

    Lin, Jyh Ming; Prakasha Gowda, A. S.; Sharma, Arun K.; Amin, Shantu

    2012-01-01

    Honokiol possesses many pharmacological activities including anti-cancer properties. Here in, we designed and synthesized honokiol analogs that block major honokiol metabolic pathway which may enhance their effectiveness. We studied their cytotoxicity in human cancer cells and evaluate possible mechanism of cell cycle arrest. Two analogs, namely 2 and 4, showed much higher growth inhibitory activity in A549 human lung cancer cells and significant increase of cell population in the G0-G1 phase. Further elucidation of the inhibition mechanism on cell cycle showed that analogs 2 and 4 inhibit both CDK11 and cyclin B1protien levels in A549 cells. PMID:22533983

  11. Individual strains of Lactobacillus paracasei differentially inhibit human basophil and mouse mast cell activation

    PubMed Central

    Cassard, Lydie; Lalanne, Ana Inés; Garault, Peggy; Cotillard, Aurélie; Chervaux, Christian; Wels, Michiel; Smokvina, Tamara

    2016-01-01

    Abstract Introduction The microbiota controls a variety of biological functions, including immunity, and alterations of the microbiota in early life are associated with a higher risk of developing allergies later in life. Several probiotic bacteria, and particularly lactic acid bacteria, were described to reduce both the induction of allergic responses and allergic manifestations. Although specific probiotic strains were used in these studies, their protective effects on allergic responses also might be common for all lactobacilli. Methods To determine whether allergic effector cells inhibition is a common feature of lactobacilli or whether it varies among lactobacilli strains, we compared the ability of 40 strains of the same Lactobacillus paracasei species to inhibit IgE‐dependent mouse mast cell and human basophil activation. Results We uncovered a marked heterogeneity in the inhibitory properties of the 40 Lactobacillus strains tested. These segregated into three to four clusters depending on the intensity of inhibition. Some strains inhibited both mouse mast cell and human basophil activation, others strains inhibited only one cell type and another group induced no inhibition of activation for either cell type. Conclusions Individual Lactobacillus strains of the same species differentially inhibit IgE‐dependent activation of mouse mast cells and human basophils, two cell types that are critical in the onset of allergic manifestations. Although we failed to identify specific bacterial genes associated with inhibition by gene‐trait matching analysis, our findings demonstrate the complexity of the interactions between the microbiota and the host. These results suggest that some L. paracasei strains might be more beneficial in allergies than others strains and provide the bases for a rational screening of lactic acid bacteria strains as next‐generation probiotics in the field of allergy. PMID:27621812

  12. Use of Human Plasma Samples to Identify Circulating Drug Metabolites that Inhibit Cytochrome P450 Enzymes.

    PubMed

    Eng, Heather; Obach, R Scott

    2016-08-01

    Drug interactions elicited through inhibition of cytochrome P450 (P450) enzymes are important in pharmacotherapy. Recently, greater attention has been focused on not only parent drugs inhibiting P450 enzymes but also on possible inhibition of these enzymes by circulating metabolites. In this report, an ex vivo method whereby the potential for circulating metabolites to be inhibitors of P450 enzymes is described. To test this method, seven drugs and their known plasma metabolites were added to control human plasma at concentrations previously reported to occur in humans after administration of the parent drug. A volume of plasma for each drug based on the known inhibitory potency and time-averaged concentration of the parent drug was extracted and fractionated by high-pressure liquid chromatography-mass spectrometry, and the fractions were tested for inhibition of six human P450 enzyme activities (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4). Observation of inhibition in fractions that correspond to the retention times of metabolites indicates that the metabolite has the potential to contribute to P450 inhibition in vivo. Using this approach, norfluoxetine, hydroxyitraconazole, desmethyldiltiazem, desacetyldiltiazem, desethylamiodarone, hydroxybupropion, erythro-dihydrobupropion, and threo-dihydrobupropion were identified as circulating metabolites that inhibit P450 activities at a similar or greater extent as the parent drug. A decision tree is presented outlining how this method can be used to determine when a deeper investigation of the P450 inhibition properties of a drug metabolite is warranted. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  13. Inhibition behavior of fructus psoraleae's ingredients towards human carboxylesterase 1 (hCES1).

    PubMed

    Sun, Dong-Xue; Ge, Guang-Bo; Dong, Pei-Pei; Cao, Yun-Feng; Fu, Zhi-Wei; Ran, Rui-Xue; Wu, Xue; Zhang, Yan-Yan; Hua, Hui-Ming; Zhao, Zhenying; Fang, Zhong-Ze

    2016-01-01

    1. Fructus psoraleae (FP) is the dried ripe seeds of Psoralea corylifolia L. (Fabaceae) widely used in Asia, and has been reported to exert important biochemical and pharmacological activities. The adverse effects of FP remain unclear. The present study aims to determine the inhibition of human carboxylesterase 1 (CES1) by FP's major ingredients, including neobavaisoflavone, corylifolinin, coryfolin, psoralidin, corylin and bavachinin. 2. The probe substrate of CES1 2-(2-benzoyl-3-methoxyphenyl) benzothiazole (BMBT) was derived from 2-(2-hydroxy-3-methoxyphenyl) benzothiazole (HMBT), and human liver microsomes (HLMs)-catalyzed BMBT metabolism was used to phenotype the activity of CES1. In silico docking method was employed to explain the inhibition mechanism. 3. All the tested compounds exerted strong inhibition towards the activity of CES1 in a concentration-dependent behavior. Furthermore, the inhibition kinetics was determined for the inhibition of neobavaisoflavone, corylifolinin, coryfolin, corylin and bavachinin towards CES1. Both Dixon and Lineweaver-Burk plots showed that neobavaisoflavone, corylifolinin, coryfolin and corylin noncompetitively inhibited the activity of CES1, and bavachinin competitively inhibited the activity of CES1. The inhibition kinetic parameters (Ki) were calculated to be 5.3, 9.4, 1.9, 0.7 and 0.5 μM for neobavaisoflavone, corylifolinin, coryfolin, corylin and bavachinin, respectively. In conclusion, the inhibition behavior of CES1 by the FP's constituents was given in this article, indicating the possible adverse effects of FP through the disrupting CES1-catalyzed metabolism of endogenous substances and xenobiotics.

  14. Inhibition of human cytochrome P450 enzymes by the natural hepatotoxin safrole.

    PubMed

    Ueng, Yune-Fang; Hsieh, Chih-Hang; Don, Ming-Jaw

    2005-05-01

    The hepatotoxin, safrole is a methylenedioxy phenyl compound, found in sassafras oil and certain other essential oils. Recombinant cytochrome P450 (CYP, P450) and human liver microsomes were studied to investigate the selective inhibitory effects of safrole on human P450 enzymes and the mechanisms of action. Using Escherichia coli-expressed human P450, our results demonstrated that safrole was a non-selective inhibitor of CYP1A2, CYP2A6, CYP2D6, CYP2E1, and CYP3A4 in the IC(50) order CYP2E1 < CYP1A2 < CYP2A6 < CYP3A4 < CYP2D6. Safrole strongly inhibited CYP1A2, CYP2A6, and CYP2E1 activities with IC(50) values less than 20 microM. Safrole caused competitive, non-competitive, and non-competitive inhibition of CYP1A2, CYP2A6 and CYP2E1 activities, respectively. The inhibitor constants were in the order CYP1A2 < CYP2E1 < CYP2A6. In human liver microsomes, 50 microM safrole strongly inhibited 7-ethoxyresorufin O-deethylation, coumarin hydroxylation, and chlorzoxazone hydroxylation activities. These results revealed that safrole was a potent inhibitor of human CYP1A2, CYP2A6, and CYP2E1. With relatively less potency, CYP2D6 and CYP3A4 were also inhibited.

  15. Inhibition of plasma vasopressin after drinking in dehydrated humans

    NASA Technical Reports Server (NTRS)

    Geelen, G.; Keil, L. C.; Kravik, S. E.; Wade, C. E.; Thrasher, T. N.; Barnes, P. R.; Pyka, G.; Nesvig, C.; Greenleaf, J. E.

    1984-01-01

    The effects of nonosmotic and nonvolumetric factors on vasopressin secretion in dehydrated humans has been investigated experimentally, before and after drinking. The subjects of the experiment were five adult men and three adult women weighing 69-77 kg. In order to determine the influence of nonosmotic and nonvolumetric factors on vasopressin secretion, measurements were obtained of the following blood hematological indices: serum Na(+) content; serum K(+) content; osmolality; and hemoglobin. Measurements of hematocrit, plasma arginine vasopressin (AVP), aldosterone, and renin activity were also obtained. It is found that dehydration increased mean serum Na(+) content, osmolality,and AVP. No significant changes were observed in renin activity, hemoglobin, hematocrit, or plasma volume, while plasma aldosterone increased from 11.1 ng/dl after dehydration to 15.6 ng/dl between 30 and 60 min after drinking. A rapid fall of AVP content following rehydration occurred in the absence of changes in the primary regulators of AVP osmolality and plasma volume, with no change in blood pressure. On the basis of the experimental results, it is suggested that oropharyngeal factors may be the mechanism, for the observed decrease in AVP following rehydration.

  16. Replication of many human viruses is refractory to inhibition by endogenous cellular microRNAs.

    PubMed

    Bogerd, Hal P; Skalsky, Rebecca L; Kennedy, Edward M; Furuse, Yuki; Whisnant, Adam W; Flores, Omar; Schultz, Kimberly L W; Putnam, Nicole; Barrows, Nicholas J; Sherry, Barbara; Scholle, Frank; Garcia-Blanco, Mariano A; Griffin, Diane E; Cullen, Bryan R

    2014-07-01

    The issue of whether viruses are subject to restriction by endogenous microRNAs (miRNAs) and/or by virus-induced small interfering RNAs (siRNAs) in infected human somatic cells has been controversial. Here, we address this question in two ways. First, using deep sequencing, we demonstrate that infection of human cells by the RNA virus dengue virus (DENV) or West Nile virus (WNV) does not result in the production of any virus-derived siRNAs or viral miRNAs. Second, to more globally assess the potential of small regulatory RNAs to inhibit virus replication, we used gene editing to derive human cell lines that lack a functional Dicer enzyme and that therefore are unable to produce miRNAs or siRNAs. Infection of these cells with a wide range of viruses, including DENV, WNV, yellow fever virus, Sindbis virus, Venezuelan equine encephalitis virus, measles virus, influenza A virus, reovirus, vesicular stomatitis virus, human immunodeficiency virus type 1, or herpes simplex virus 1 (HSV-1), failed to reveal any enhancement in the replication of any of these viruses, although HSV-1, which encodes at least eight Dicer-dependent viral miRNAs, did replicate somewhat more slowly in the absence of Dicer. We conclude that most, and perhaps all, human viruses have evolved to be resistant to inhibition by endogenous human miRNAs during productive replication and that dependence on a cellular miRNA, as seen with hepatitis C virus, is rare. How viruses have evolved to avoid inhibition by endogenous cellular miRNAs, which are generally highly conserved during metazoan evolution, remains to be determined. Importance: Eukaryotic cells express a wide range of small regulatory RNAs, including miRNAs, that have the potential to inhibit the expression of mRNAs that show sequence complementarity. Indeed, previous work has suggested that endogenous miRNAs have the potential to inhibit viral gene expression and replication. Here, we demonstrate that the replication of a wide range of

  17. Replication of Many Human Viruses Is Refractory to Inhibition by Endogenous Cellular MicroRNAs

    PubMed Central

    Bogerd, Hal P.; Skalsky, Rebecca L.; Kennedy, Edward M.; Furuse, Yuki; Whisnant, Adam W.; Flores, Omar; Schultz, Kimberly L. W.; Putnam, Nicole; Barrows, Nicholas J.; Sherry, Barbara; Scholle, Frank; Garcia-Blanco, Mariano A.; Griffin, Diane E.

    2014-01-01

    ABSTRACT The issue of whether viruses are subject to restriction by endogenous microRNAs (miRNAs) and/or by virus-induced small interfering RNAs (siRNAs) in infected human somatic cells has been controversial. Here, we address this question in two ways. First, using deep sequencing, we demonstrate that infection of human cells by the RNA virus dengue virus (DENV) or West Nile virus (WNV) does not result in the production of any virus-derived siRNAs or viral miRNAs. Second, to more globally assess the potential of small regulatory RNAs to inhibit virus replication, we used gene editing to derive human cell lines that lack a functional Dicer enzyme and that therefore are unable to produce miRNAs or siRNAs. Infection of these cells with a wide range of viruses, including DENV, WNV, yellow fever virus, Sindbis virus, Venezuelan equine encephalitis virus, measles virus, influenza A virus, reovirus, vesicular stomatitis virus, human immunodeficiency virus type 1, or herpes simplex virus 1 (HSV-1), failed to reveal any enhancement in the replication of any of these viruses, although HSV-1, which encodes at least eight Dicer-dependent viral miRNAs, did replicate somewhat more slowly in the absence of Dicer. We conclude that most, and perhaps all, human viruses have evolved to be resistant to inhibition by endogenous human miRNAs during productive replication and that dependence on a cellular miRNA, as seen with hepatitis C virus, is rare. How viruses have evolved to avoid inhibition by endogenous cellular miRNAs, which are generally highly conserved during metazoan evolution, remains to be determined. IMPORTANCE Eukaryotic cells express a wide range of small regulatory RNAs, including miRNAs, that have the potential to inhibit the expression of mRNAs that show sequence complementarity. Indeed, previous work has suggested that endogenous miRNAs have the potential to inhibit viral gene expression and replication. Here, we demonstrate that the replication of a wide range of

  18. AT7867 Inhibits Human Colorectal Cancer Cells via AKT-Dependent and AKT-Independent Mechanisms

    PubMed Central

    Yao, Chen; Huang, Ping; Zhang, Yi; Cao, Shibing; Li, Xiangcheng

    2017-01-01

    AKT is often hyper-activated in human colorectal cancers (CRC). This current study evaluated the potential anti-CRC activity by AT7867, a novel AKT and p70S6K1 (S6K1) dual inhibitor. We showed that AT7867 inhibited survival and proliferation of established (HT-29, HCT116 and DLD-1 lines) and primary human CRC cells. Meanwhile, it provoked caspase-dependent apoptosis in the CRC cells. Molecularly, AT7867 blocked AKT-S6K1 activation in CRC cells. Restoring AKT-S6K1 activation, via expression of a constitutively-active AKT1 (“ca-AKT1”), only partially attenuated AT7867-induced HT-29 cell death. Further studies demonstrated that AT7867 inhibited sphingosine kinase 1 (SphK1) activity to promote pro-apoptotic ceramide production in HT-29 cells. Such effects by AT7867 were independent of AKT inhibition. AT7867-indued ceramide production and subsequent HT-29 cell apoptosis were attenuated by co-treatment of sphingosine-1-phosphate (S1P), but were potentiated with the glucosylceramide synthase (GCS) inhibitor PDMP. In vivo, intraperitoneal injection of AT7867 inhibited HT-29 xenograft tumor growth in nude mice. AKT activation was also inhibited in AT7867-treated HT-29 tumors. Together, the preclinical results suggest that AT7867 inhibits CRC cells via AKT-dependent and -independent mechanisms. PMID:28081222

  19. Interactions between glutamate, dopamine, and the neuronal signature of response inhibition in the human striatum.

    PubMed

    Lorenz, Robert C; Gleich, Tobias; Buchert, Ralph; Schlagenhauf, Florian; Kühn, Simone; Gallinat, Jürgen

    2015-10-01

    Response inhibition is a basic mechanism in cognitive control and dysfunctional in major psychiatric disorders. The neuronal mechanisms are in part driven by dopamine in the striatum. Animal data suggest a regulatory role of glutamate on the level of the striatum. We used a trimodal imaging procedure of the human striatum including F18-DOPA positron emission tomography, proton magnetic resonance spectroscopy, and functional magnetic resonance imaging of a stop signal task. We investigated dopamine synthesis capacity and glutamate concentration in vivo and their relation to functional properties of response inhibition. A mediation analysis revealed a significant positive association between dopamine synthesis capacity and inhibition-related neural activity in the caudate nucleus. This relationship was significantly mediated by striatal glutamate concentration. Furthermore, stop signal reaction time was inversely related to striatal activity during inhibition. The data show, for the first time in humans, an interaction between dopamine, glutamate, and the neural signature of response inhibition in the striatum. This finding stresses the importance of the dopamine-glutamate interaction for behavior and may facilitate the understanding of psychiatric disorders characterized by impaired response inhibition.

  20. Purinergic signaling inhibits human acute myeloblastic leukemia cell proliferation, migration, and engraftment in immunodeficient mice.

    PubMed

    Salvestrini, Valentina; Zini, Roberta; Rossi, Lara; Gulinelli, Sara; Manfredini, Rossella; Bianchi, Elisa; Piacibello, Wanda; Caione, Luisa; Migliardi, Giorgia; Ricciardi, Maria Rosaria; Tafuri, Agostino; Romano, Marco; Salati, Simona; Di Virgilio, Francesco; Ferrari, Sergio; Baccarani, Michele; Ferrari, Davide; Lemoli, Roberto M

    2012-01-05

    Extracellular ATP and UTP nucleotides increase the proliferation and engraftment potential of normal human hematopoietic stem cells via the engagement of purinergic receptors (P2Rs). In the present study, we show that ATP and UTP have strikingly opposite effects on human acute myeloblastic leukemia (AML) cells. Leukemic cells express P2Rs. ATP-stimulated leukemic cells, but not normal CD34+ cells, undergo down-regulation of genes involved in cell proliferation and migration, whereas cell-cycle inhibitors are up-regulated. Functionally, ATP induced the inhibition of proliferation and accumulation of AML cells, but not of normal cells, in the G0 phase of the cell cycle. Exposure to ATP or UTP inhibited AML-cell migration in vitro. In vivo, xenotransplantation experiments demonstrated that the homing and engraftment capacity of AML blasts and CD34+CD38- cells to immunodeficient mice BM was significantly inhibited by pretreatment with nucleotides. P2R-expression analysis and pharmacologic profiling suggested that the inhibition of proliferation by ATP was mediated by the down-regulation of the P2X7R, which is up-regulated on untreated blasts, whereas the inhibition of chemotaxis was mainly mediated via P2Y2R and P2Y4R subtypes. We conclude that, unlike normal cells, P2R signaling inhibits leukemic cells and therefore its pharmacologic modulation may represent a novel therapeutic strategy.

  1. Highly chlorinated PCBs inhibit the human xenobiotic response mediated by the steroid and xenobiotic receptor (SXR).

    PubMed Central

    Tabb, Michelle M; Kholodovych, Vladyslav; Grün, Felix; Zhou, Changcheng; Welsh, William J; Blumberg, Bruce

    2004-01-01

    Polychlorinated biphenyls (PCBs) are a family of persistent organic contaminants suspected to cause adverse effects in wildlife and humans. In rodents, PCBs bind to the aryl hydrocarbon (AhR) and pregnane X receptors (PXR) inducing the expression of catabolic cytochrome p450 enzymes of the CYP1A and 3A families. We found that certain highly chlorinated PCBs are potent activators of rodent PXR but antagonize its human ortholog, the steroid and xenobiotic receptor (SXR), inhibiting target gene induction. Thus, exposure to PCBs may blunt the human xenobiotic response, inhibiting the detoxification of steroids, bioactive dietary compounds, and xenobiotics normally mediated by SXR. The antagonistic PCBs are among the most stable and abundant in human tissues. These findings have important implications for understanding the biologic effects of PCB exposure and the use of animal models to predict the attendant risk. PMID:14754570

  2. Highly chlorinated PCBs inhibit the human xenobiotic response mediated by the steroid and xenobiotic receptor (SXR).

    PubMed

    Tabb, Michelle M; Kholodovych, Vladyslav; Grün, Felix; Zhou, Changcheng; Welsh, William J; Blumberg, Bruce

    2004-02-01

    Polychlorinated biphenyls (PCBs) are a family of persistent organic contaminants suspected to cause adverse effects in wildlife and humans. In rodents, PCBs bind to the aryl hydrocarbon (AhR) and pregnane X receptors (PXR) inducing the expression of catabolic cytochrome p450 enzymes of the CYP1A and 3A families. We found that certain highly chlorinated PCBs are potent activators of rodent PXR but antagonize its human ortholog, the steroid and xenobiotic receptor (SXR), inhibiting target gene induction. Thus, exposure to PCBs may blunt the human xenobiotic response, inhibiting the detoxification of steroids, bioactive dietary compounds, and xenobiotics normally mediated by SXR. The antagonistic PCBs are among the most stable and abundant in human tissues. These findings have important implications for understanding the biologic effects of PCB exposure and the use of animal models to predict the attendant risk.

  3. Role of Yops in inhibition of phagocytosis and killing of opsonized Yersinia enterocolitica by human granulocytes.

    PubMed

    Visser, L G; Annema, A; van Furth, R

    1995-07-01

    The virulence plasmid of Yersinia enterocolitica codes for the production of the outer membrane protein YadA and the secretion of several proteins, called Yops, which may play a role in the interaction between granulocytes and this bacterium. We investigated whether the expression of YadA or the secretion of Yops affected the phagocytosis and killing of opsonized Y. enterocolitica by human granulocytes. The rates of phagocytosis and killing of Y. enterocolitica by granulocytes in suspension in the presence of rabbit Yersinia antibodies and complement were determined by microbiological assays. In addition, noningested cell-adherent bacteria were differentiated from ingested yersiniae by immunofluorescence microscopy. Plasmid-bearing opsonized Y. enterocolitica was able to inhibit phagocytosis and killing by human granulocytes. The inhibition of phagocytosis was specific for the plasmid-bearing strain of Y. enterocolitica, since granulocytes were still able to phagocytose and kill Staphylococcus aureus in the presence of Y. enterocolitica. Plasmid-cured Y. enterocolitica was readily phagocytosed and killed by these cells. To investigate the role of YadA or Yops in the inhibition of phagocytosis by granulocytes, the phagocytosis of mutant strains unable to express YadA or to secrete Yops was studied. A Y. enterocolitica mutant unable to secrete Yops lost its ability to inhibit phagocytosis; a mutant expressing only YadA was readily ingested by granulocytes. These results indicate that after attachment of opsonized Y. enterocolitica to granulocytes, Yops play an important role in inhibiting the ingestion of Y. enterocolitica by human granulocytes.

  4. Analysis of the mechanisms of human cytotoxic T lymphocyte response inhibition by NO.

    PubMed

    Blesson, Séverine; Thiery, Jérôme; Gaudin, Catherine; Stancou, Rodica; Kolb, Jean-Pierre; Moreau, Jean-Louis; Theze, Jacques; Mami-Chouaib, Fathia; Chouaib, Salem

    2002-10-01

    NO is a potent cellular mediator which has been shown to modulate several immune mechanisms. Using human T lymphocytes as responder cells in a primary mixed lymphocyte reaction, we demonstrated that, at the initiation of the culture, exogenously provided NO via sodium nitroprusside, in non-toxic concentrations, inhibited both allogeneic proliferative and primary cytotoxic responses in a dose-dependent manner. In contrast, it had no effect on the cytotoxic activity of established human TCR (alpha)beta and TCR (gamma)delta cytotoxic T lymphocyte (CTL) clones. The NO inhibitory effect on primary cytotoxic T cell response correlates with inhibition of T cell blastogenesis. Furthermore, under our stimulation conditions, NO induced an inhibition of IL-2 production, an alteration of IL-2R(alpha) expression, and a down-regulation of NF-AT translocation in CD4(+) and CD8(+)allostimulated T cells. Furthermore, we demonstrate that the inhibition of allospecific CTL activity by the NO donor was at least in part related to an inhibition of granzyme B and Fas ligand transcription as revealed respectively by RNase protection and RT-PCR analysis. These results suggest that NO may function to fine tune human CD3(+) T cell activation and subsequent CTL generation.

  5. Comparative sensitivity of human and rat neural cultures to chemical-induced inhibition of neurite outgrowth

    SciTech Connect

    Harrill, Joshua A.; Freudenrich, Theresa M.; Robinette, Brian L.; Mundy, William R.

    2011-11-15

    There is a need for rapid, efficient and cost-effective alternatives to traditional in vivo developmental neurotoxicity testing. In vitro cell culture models can recapitulate many of the key cellular processes of nervous system development, including neurite outgrowth, and may be used as screening tools to identify potential developmental neurotoxicants. The present study compared primary rat cortical cultures and human embryonic stem cell-derived neural cultures in terms of: 1) reproducibility of high content image analysis based neurite outgrowth measurements, 2) dynamic range of neurite outgrowth measurements and 3) sensitivity to chemicals which have been shown to inhibit neurite outgrowth. There was a large increase in neurite outgrowth between 2 and 24 h in both rat and human cultures. Image analysis data collected across multiple cultures demonstrated that neurite outgrowth measurements in rat cortical cultures were more reproducible and had higher dynamic range as compared to human neural cultures. Human neural cultures were more sensitive than rat cortical cultures to chemicals previously shown to inhibit neurite outgrowth. Parallel analysis of morphological (neurite count, neurite length) and cytotoxicity (neurons per field) measurements were used to detect selective effects on neurite outgrowth. All chemicals which inhibited neurite outgrowth in rat cortical cultures did so at concentrations which did not concurrently affect the number of neurons per field, indicating selective effects on neurite outgrowth. In contrast, more than half the chemicals which inhibited neurite outgrowth in human neural cultures did so at concentrations which concurrently decreased the number of neurons per field, indicating that effects on neurite outgrowth were secondary to cytotoxicity. Overall, these data demonstrate that the culture models performed differently in terms of reproducibility, dynamic range and sensitivity to neurite outgrowth inhibitors. While human neural

  6. Vanadate monomers and dimers both inhibit the human prostatic acid phosphatase.

    PubMed

    Crans, D C; Simone, C M; Saha, A K; Glew, R H

    1989-11-30

    A combination of enzyme kinetics and 51V NMR spectroscopy was used to identify the species of vanadate that inhibits acid phosphatases. Monomeric vanadate was shown to inhibit wheat germ and potato acid phosphatases. At pH 5.5, the vanadate dimer inhibits the human prostatic acid phosphatase whereas at pH 7.0 it is the vanadate monomer that inhibits this enzyme. The pH-dependent shift in the affinity of the prostatic phosphatase for vanadate is presumably due to deprotonation of an amino acid side chain in or near the binding site resulting in a conformational change in the protein. pH may be a subtle effector of the insulin-like vanadate activity in biological systems and may explain some of the differences in selectivity observed with the protein phosphatases.

  7. Irreversible inhibition of human cathepsins B, L, S and K by hypervalent tellurium compounds.

    PubMed

    Cunha, Rodrigo L O R; Gouvêa, Iuri E; Feitosa, Geovana P V; Alves, Márcio F M; Brömme, Dieter; Comasseto, João V; Tersariol, Ivarne L S; Juliano, Luiz

    2009-11-01

    The inhibition of human cysteine cathepsins B, L, S and K was evaluated by a set of hypervalent tellurium compounds (telluranes) comprising both organic and inorganic derivatives. All telluranes studied showed a time- and concentration-dependent irreversible inhibition of the cathepsins, and their second-order inactivation rate constants were determined. The organic derivatives were potent inhibitors of the cathepsins and clear specificities were detected, which were parallel to their known substrate specificities. In all cases, the activity of the tellurane-inhibited cathepsins was recovered by treatment of the inactivated enzymes with reducing agents. The maximum stoichiometry of the reaction between cysteine residues and telluranes were also determined. The presented data indicate that it is possible to design organic compounds with a tellurium(IV) moiety as a novel warhead that covalently modifies the catalytic cysteine, and which also form strong interactions with subsites of cathepsins B, L, S and K, resulting in more specific inhibition.

  8. Vitamin E inhibits proliferation of human Tenon's capsule fibroblasts in vitro.

    PubMed

    Haas, A L; Boscoboinik, D; Mojon, D S; Böhnke, M; Azzi, A

    1996-01-01

    Failure of glaucoma surgery is mostly due to fibrocellular scar formation, derived from Tenon's capsule fibroblasts. In high-risk cases, postoperative Tenon's capsule fibroblast proliferation is inhibited by mitomycin C or 5-fluorouracil. Toxicity to other ocular cell types and the risk of ocular hypotony limits the use of these agents. We have found that d-alpha-tocopherol (vitamin E) was able to inhibit proliferation of in vitro human Tenon's capsule fibroblasts obtained from seven different donors. At 48 h, inhibition of cell proliferation was 30-78% (mean 60%) for 50 microM d-alpha-tocopherol and 46-97% (mean 77%) for 100 microM d-alpha-tocopherol. This inhibition was statistically significant. No cytotoxic effects were observed.

  9. The inhibition of Wnt/β-catenin signaling pathway in human colon cancer cells by sulindac.

    PubMed

    Tai, Wei-Ping; Hu, Pin-Jin; Wu, Jing; Lin, Xiang-Chun

    2014-01-01

    The aberrant activation of Wnt/β-catenin signaling plays important roles in the initial development of colon cancer. Sulindac is a commonly used non-steroidal anti-inflammatory drug. We demonstrated the effects of sulindac on growth inhibition, apoptosis induction, and Wnt/β-catenin signaling suppression in human colon cancer cells. Sulindac significantly inhibited proliferation of HT-29 colon cancer cells in a dose- and time-dependent manner. Sulindac was found to induce the apoptosis of HT-29 cells and inhibit the Wnt/β-catenin pathway. The inhibition was further confirmed by the decreased protein levels of β-catenin. The results indicate that sulindac may play a beneficial role in the comprehensive treatment of colon cancer.

  10. A beta-linked mannan inhibits adherence of Pseudomonas aeruginosa to human lung epithelial cells.

    PubMed

    Azghani, A O; Williams, I; Holiday, D B; Johnson, A R

    1995-02-01

    Adherence through carbohydrate-binding adhesins is an early step in colonization of the lung by gram-negative organisms, and because published data indicate that binding involves mannose groups, we tested the ability of a beta-linked acetyl-mannan (acemannan) to inhibit adherence of Pseudomonas aeruginosa to cultures of human lung epithelial cells. Adherence of radiolabelled P.aeruginosa to A549 cells (a type II-like pneumocyte line) increased linearly with the duration of the incubation. Acemannan inhibited adherence of bacteria, and the extent of inhibition was related to the concentration of the mannan. Inhibition required continued contact between acemannan and the target epithelial cells; cells washed free of acemannan no longer discouraged bacterial binding. Comparison of binding between seven different strains of P.aeruginosa indicated that fewer mucoid than non-mucoid bacteria adhered, but binding of either phenotype was inhibited by acemannan. Mannose, methyl alpha-D-mannopyranoside, methyl beta-D-mannopyranoside and dextran did not affect adherence of any of the non-mucoid strains. Mannose inhibited adherence by one mucoid strain, but not the other, indicating differences between strains of the same phenotype. Since prior treatment of epithelial cells with concanavalin A did not affect acemannan-induced inhibition of bacterial adherence, we concluded that the inhibitory effect of acemannan probably does not involve mannose-containing receptors.

  11. Interleukin 2 inhibits in vitro growth of human T cell lines carrying retrovirus.

    PubMed

    Sugamura, K; Nakai, S; Fujii, M; Hinuma, Y

    1985-05-01

    Four human T cell lines, TL-Mor, TL-Su, TL-TerI, and TL-OmI, carrying human T cell leukemia virus (HTLV), were established previously. TL-Mor, TL-Su, and TL-TerI were derived from interleukin 2 (IL-2)-dependent parental cell lines cloned from peripheral blood leukocytes (PBL) of three healthy HTLV carriers, while TL-OmI was directly established from PBL of a patient with adult T cell leukemia. These four TL cell lines grow autonomously without IL-2. When they were cultured in the presence of IL-2, their growth was inhibited after a few days. This growth inhibition depended on the dose of IL-2, and the effective dose significantly promoted growth of their parental IL-2-dependent cell lines. The growth inhibition is demonstrated to be due to specific binding of IL-2 to receptors on the TL cells.

  12. Inhibition of human low-density lipoprotein oxidation in vitro by ginger extracts.

    PubMed

    Gunathilake, K D Prasanna P; Rupasinghe, H P Vasantha

    2014-04-01

    Oxidative modification of low-density lipoprotein (LDL) is thought to play a key role in atherosclerotic plaque formation. Currently, there is a renewed interest in ginger because of its antioxidants and cardioprotective properties. The effects of ethanol, methanol, ethyl acetate, and hexane solvent extracts of ginger and pure major ginger constituents on Cu(2+)-induced oxidation of human LDL in vitro were examined. The LDL oxidation inhibition by ethanol, methanol, ethyl acetate, and hexane extracts of ginger was 71%, 76%, 67%, and 67%, respectively, at their optimum extraction conditions. Inhibition of LDL oxidation by water extracts of ginger, which was prepared by ultrasonic-assisted extraction conditions of 52°C for 15 min, was about 43%. Phenolic bioactives of ginger-6-gingerols, 8-gingerols, 10-gingerols, and 6-shogaol-seem to be strong inhibitors of Cu(+2)-induced LDL oxidation. Overall, ginger extracts, including the water extract possess the antioxidant activities to inhibit human LDL oxidation in vitro.

  13. Inhibition of RNA Polymerase II Transcription in Human Cells by Synthetic DNA-Binding Ligands

    NASA Astrophysics Data System (ADS)

    Dickinson, Liliane A.; Gulizia, Richard J.; Trauger, John W.; Baird, Eldon E.; Mosier, Donald E.; Gottesfeld, Joel M.; Dervan, Peter B.

    1998-10-01

    Sequence-specific DNA-binding small molecules that can permeate human cells potentially could regulate transcription of specific genes. Multiple cellular DNA-binding transcription factors are required by HIV type 1 for RNA synthesis. Two pyrrole--imidazole polyamides were designed to bind DNA sequences immediately adjacent to binding sites for the transcription factors Ets-1, lymphoid-enhancer binding factor 1, and TATA-box binding protein. These synthetic ligands specifically inhibit DNA-binding of each transcription factor and HIV type 1 transcription in cell-free assays. When used in combination, the polyamides inhibit virus replication by >99% in isolated human peripheral blood lymphocytes, with no detectable cell toxicity. The ability of small molecules to target predetermined DNA sequences located with RNA polymerase II promoters suggests a general approach for regulation of gene expression, as well as a mechanism for the inhibition of viral replication.

  14. Differential inhibition of aflatoxin B1 oxidation by gestodene action on human liver microsomes.

    PubMed

    Kim, B R; Oh, H S; Kim, D H

    1997-11-01

    Human cytochrome P450 (P450) 3A is known to be involved in the formation of both aflatoxin B1-exo-8,9-epoxide (exo-epoxidation) and aflatoxin Q1 (3 alpha-hydroxylation). Gestodene, a known inactivator of P450 3A4, inhibited the formation of AFB1 metabolites in a variety of ways depending on the incubation condition. Preincubation of gestodene with human liver microsomes prior to the addition of AFB1 inhibited both exo-epoxidation and 3 alpha-hydroxylation whereas simultaneous incubation of gestodene with AFB1 only inhibited 3 alpha-hydroxylation. These results suggest that two independent substrate binding sites exist in P450 3A4, and AFB1 binds to both of the binding sites. Gestodene selectively binds to one of the binding sites leading to the formation of AFQ1, whereas it does not affect the formation of exo-epoxide via the other binding site.

  15. Potent and long-lasting inhibition of human P2X2 receptors by copper

    PubMed Central

    Punthambaker, Sukanya; Hume, Richard I.

    2013-01-01

    P2X receptors are ion channels gated by ATP. In rodents these channels are modulated by zinc and copper. Zinc is co-released with neurotransmitter at some synapses and can modulate neuronal activity, but the role of copper in the brain is unclear. Rat P2X2 receptors show potentiation by 2–100 µM zinc or copper in the presence of a submaximal concentration of ATP but are inhibited by zinc or copper at concentrations above 100 µM. In contrast, human P2X2 (hP2X2) receptors show no potentiation and are strongly inhibited by zinc over the range of 2–100 µM. The effect of copper on hP2X2 is of interest because there are human brain disorders in which copper concentration is altered. We found that hP2X2 receptors are potently inhibited by copper (IC50 = 40 nM). ATP responsiveness recovered extremely slowly after copper washout, with full recovery requiring over 1 h. ATP binding facilitated copper binding but not unbinding from this inhibitory site. A mutant receptor in which the first six extracellular cysteines were deleted, C(1–6)S, showed normal copper inhibition, however reducing agents dramatically accelerated recovery from copper inhibition in wild type hP2X2 and the C(1–6)S mutant, indicating that the final two disulfide bonds are required to maintain the high affinity copper binding site. Three histidine residues required for normal zinc inhibition were also required for normal copper inhibition. Humans with untreated Wilson’s disease have excess amounts of copper in the brain. The high copper sensitivity of hP2X2 receptors suggests that they are non-functional in these patients. PMID:24067922

  16. Cordycepin Induces Apoptosis and Inhibits Proliferation of Human Lung Cancer Cell Line H1975 via Inhibiting the Phosphorylation of EGFR.

    PubMed

    Wang, Zheng; Wu, Xue; Liang, Yan-Ni; Wang, Li; Song, Zhong-Xing; Liu, Jian-Li; Tang, Zhi-Shu

    2016-09-27

    Cordycepin is an active component of the traditional Chinese medicine Cordyceps sinensis and Cordyceps militaris with notable anticancer activity. Though the prominent inhibitory activity was reported in different kinds of cancer cell lines, the concrete mechanisms remain elusive. It was reported that cordycepin could be converted into tri-phosphates in vivo to confuse a number of enzymes and interfere the normal cell function. For the inhibitory mechanism of EGFR inhibitors and the structure similarity of ATP and tri-phosphated cordycepin, human lung cancer cell line H1975 was employed to investigate the inhibitory effect of cordycepin. The results showed that cordycepin could inhibit cell proliferation and induce apoptosis in a dose-dependent manner. Cell cycle analysis revealed that H1975 cells could be arrested at the G₀/G₁ phase after cordycepin treatment. The expression levels of apoptosis-related protein Caspase-3 and Bcl-2 and phosphorylated expression levels of EGFR, AKT and ERK1/2 were all decreased compared with the control group stimulated with EGF. However, the protein expression levels of proapoptotic protein Bax and cleaved caspase-3 were increased. These results implied that cordycepin could inhibit cell proliferation and induce apoptosis via the EGFR signaling pathway. Our results indicated that there was potential to seek a novel EGFR inhibitor from cordycepin and its chemical derivatives.

  17. Inhibition of Sendai virus fusion with phospholipid vesicles and human erythrocyte membranes by hydrophobic peptides

    SciTech Connect

    Kelsey, D.R.; Flanagan, T.D.; Young, J.E.; Yeagle, P.L. )

    1991-06-01

    Hydrophobic di- and tripeptides which are capable of inhibiting enveloped virus infection of cells are also capable of inhibiting at least three different types of membrane fusion events. Large unilamellar vesicles (LUV) of N-methyl dioleoylphosphatidylethanolamine (N-methyl DOPE), containing encapsulated 1-aminonaphthalene-3,6,8-trisulfonic acid (ANTS) and/or p-xylene bis(pyridinium bromide) (DPX), were formed by extrusion. Vesicle fusion and leakage were then monitored with the ANTS/DPX fluorescence assay. Sendai virus fusion with lipid vesicles and Sendai virus fusion with human erythrocyte membranes were measured by following the relief of fluorescence quenching of virus labeled with octadecylrhodamine B chloride (R18). This study found that the effectiveness of the peptides carbobenzoxy-L-Phe-L-Phe (Z-L-Phe-L-Phe), Z-L-Phe, Z-D-Phe, and Z-Gly-L-Phe-L-Phe in inhibiting N-methyl DOPE LUV fusion or fusion of virus with N-methyl DOPE LUV also paralleled their reported ability to block viral infectivity. Furthermore, Z-D-Phe-L-PheGly and Z-Gly-L-Phe inhibited Sendai virus fusion with human erythrocyte membranes with the same relative potency with which they inhibited vesicle-vesicle and virus-vesicle fusion. The evidence suggests a mechanism by which these peptides exert their inhibition of plaque formation by enveloped viruses. This class of inhibitors apparently acts by inhibiting fusion of the viral envelope with the target cell membrane, thereby preventing viral infection. The physical pathway by which these peptides inhibit membrane fusion was investigated. {sup 31}P nuclear magnetic resonance (NMR) of proposed intermediates in the pathway for membrane fusion in LUV revealed that the potent fusion inhibitor Z-D-Phe-L-PheGly selectively altered the structure (or dynamics) of the hypothesized fusion intermediates and that the poor inhibitor Z-Gly-L-Phe did not.

  18. Mercury and zinc differentially inhibit shark and human CFTR orthologues: involvement of shark cysteine 102.

    PubMed

    Weber, Gerhard J; Mehr, Ali Poyan; Sirota, Jeffrey C; Aller, Stephen G; Decker, Sarah E; Dawson, David C; Forrest, John N

    2006-03-01

    The apical membrane is an important site of mercury toxicity in shark rectal gland tubular cells. We compared the effects of mercury and other thiol-reacting agents on shark CFTR (sCFTR) and human CFTR (hCFTR) chloride channels using two-electrode voltage clamping of cRNA microinjected Xenopus laevis oocytes. Chloride conductance was stimulated by perfusing with 10 microM forskolin (FOR) and 1 mM IBMX, and then thio-reactive species were added. In oocytes expressing sCFTR, FOR + IBMX mean stimulated Cl(-) conductance was inhibited 69% by 1 microM mercuric chloride and 78% by 5 microM mercuric chloride (IC(50) of 0.8 microM). Despite comparable stimulation of conductance, hCFTR was insensitive to 1 microM HgCl(2) and maximum inhibition was 15% at the highest concentration used (5 microM). Subsequent exposure to glutathione (GSH) did not reverse the inhibition of sCFTR by mercury, but dithiothreitol (DTT) completely reversed this inhibition. Zinc (50-200 microM) also reversibly inhibited sCFTR (40-75%) but did not significantly inhibit hCFTR. Similar inhibition of sCFTR but not hCFTR was observed with an organic mercurial, p-chloromercuriphenylsulfonic acid (pCMBS). The first membrane spanning domain (MSD1) of sCFTR contains two unique cysteines, C102 and C303. A chimeric construct replacing MSD1 of hCFTR with the corresponding sequence of sCFTR was highly sensitive to mercury. Site-specific mutations introducing the first but not the second shark unique cysteine in hCFTR MSD1 resulted in full sensitivity to mercury. These experiments demonstrate a profound difference in the sensitivity of shark vs. human CFTR to inhibition by three thiol-reactive substances, an effect that involves C102 in the shark orthologue.

  19. Blockade of MUC1 expression by glycerol guaiacolate inhibits proliferation of human breast cancer cells.

    PubMed

    Smith, J S; Colon, J; Madero-Visbal, R; Isley, B; Konduri, S D; Baker, C H

    2010-10-01

    We sought to determine whether administration of glycerol guaiacolate at an optimal biological dose inhibits human breast cancer cell growth. Human breast cancer MCF-7 and ZR-75-1 cells were treated with glycerol guaiacolate and the therapeutic efficacy and biological activity of this drug was investigated on breast cancer cell growth. MCF-7 cells were injected into the mammary fat pad of overectamized female athymic nude mice. Ten days later, animals were treated with daily intraperitoneal injections of glycerol guaiacolate for six weeks. Tumor size and volume was monitored and immunohistochemistry analysis on MUC1, p21 and ki-67 was performed. Glycerol guaiacolate decreased breast cancer cell growth in a dose-dependent manner, decreased cell migration, and caused G1 cell cycle arrest. Our results demonstrate that glycerol guaiacolate inhibits MUC1 protein and mRNA expression levels and significantly increased p21 expression in human breast cancer cells as well as induced PARP cleavage. Similarly, glycerol guaiacolate inhibited breast tumor growth in vivo as well as enhanced p21 expression and decreased breast tumor cell proliferation (ki-67 expression). Collectively, our results demonstrate that glycerol guaiacolate decreased MUC1 expression and enhanced cell growth inhibition by inducing p21 expression in breast cancer cells. These findings suggest that glycerol guaiacolate may provide a novel and effective approach for the treatment of human breast cancer.

  20. Yops of Yersinia enterocolitica Inhibit Receptor-Dependent Superoxide Anion Production by Human Granulocytes

    PubMed Central

    Visser, L. G.; Seijmonsbergen, E.; Nibbering, P. H.; van den Broek, P. J.; van Furth, R.

    1999-01-01

    The virulence plasmid-borne genes encoding Yersinia adhesin A (YadA) and several Yersinia secreted proteins (Yops) are involved in the inhibition of phagocytosis and killing of Yersinia enterocolitica by human granulocytes. One of these Yops, YopH, dephosphorylates multiple tyrosine-phosphorylated proteins in eukaryotic cells and is involved in the inhibition of phagocytosis of Y. enterocolitica by human granulocytes. We investigated whether antibody- and complement-opsonized plasmid-bearing (pYV+) Y. enterocolitica inhibits O2− production by human granulocytes in response to various stimuli and whether YopH is involved. Granulocytes were preincubated with mutant strains unable to express YadA or to secrete Yops or YopH. O2− production by granulocytes during stimulation was assessed by measuring the reduction of ferricytochrome c. PYV+ Y. enterocolitica inhibited O2− production by granulocytes incubated with opsonized Y. enterocolitica or N-formyl-Met-Leu-Phe (f-MLP). This inhibitory effect mediated by pYV did not affect receptor-independent O2− production by granulocytes in response to phorbol myristate acetate, indicating that NADPH activity remained unaffected after activation of protein kinase C. The inhibition of f-MLP-induced O2− production by granulocytes depends on the secretion of Yops and not on the expression of YadA. Insertional inactivation of the yopH gene abrogated the inhibition of phagocytosis of antibody- and complement-opsonized Y. enterocolitica by human granulocytes but not of the f-MLP-induced O2− production by granulocytes or tyrosine phosphorylation of granulocyte proteins. These findings suggest that the specific targets for YopH are not present in f-MLP receptor-linked signal transduction and that other Yop-mediated mechanisms are involved. PMID:10024567

  1. Yops of Yersinia enterocolitica inhibit receptor-dependent superoxide anion production by human granulocytes.

    PubMed

    Visser, L G; Seijmonsbergen, E; Nibbering, P H; van den Broek, P J; van Furth, R

    1999-03-01

    The virulence plasmid-borne genes encoding Yersinia adhesin A (YadA) and several Yersinia secreted proteins (Yops) are involved in the inhibition of phagocytosis and killing of Yersinia enterocolitica by human granulocytes. One of these Yops, YopH, dephosphorylates multiple tyrosine-phosphorylated proteins in eukaryotic cells and is involved in the inhibition of phagocytosis of Y. enterocolitica by human granulocytes. We investigated whether antibody- and complement-opsonized plasmid-bearing (pYV+) Y. enterocolitica inhibits O2- production by human granulocytes in response to various stimuli and whether YopH is involved. Granulocytes were preincubated with mutant strains unable to express YadA or to secrete Yops or YopH. O2- production by granulocytes during stimulation was assessed by measuring the reduction of ferricytochrome c. PYV+ Y. enterocolitica inhibited O2- production by granulocytes incubated with opsonized Y. enterocolitica or N-formyl-Met-Leu-Phe (f-MLP). This inhibitory effect mediated by pYV did not affect receptor-independent O2- production by granulocytes in response to phorbol myristate acetate, indicating that NADPH activity remained unaffected after activation of protein kinase C. The inhibition of f-MLP-induced O2- production by granulocytes depends on the secretion of Yops and not on the expression of YadA. Insertional inactivation of the yopH gene abrogated the inhibition of phagocytosis of antibody- and complement-opsonized Y. enterocolitica by human granulocytes but not of the f-MLP-induced O2- production by granulocytes or tyrosine phosphorylation of granulocyte proteins. These findings suggest that the specific targets for YopH are not present in f-MLP receptor-linked signal transduction and that other Yop-mediated mechanisms are involved.

  2. Sulindac and Its Metabolites Inhibit Multiple Transport Proteins in Rat and Human Hepatocytes

    PubMed Central

    Lee, Jin Kyung; Paine, Mary F.

    2010-01-01

    Sulindac is a commonly used nonsteroidal anti-inflammatory drug. This study tested the hypothesis that sulindac-mediated drug–drug interactions and/or hepatotoxicity may be caused, in part, by inhibition of proteins responsible for the hepatic transport of drugs and/or bile acids by sulindac and/or sulindac metabolites [sulindac sulfone (S-sulfone) and sulindac sulfide (S-sulfide)]. The uptake and excretion of model substrates, [3H]taurocholate (TC), [3H]estradiol 17-β-glucuronide (E217G), and nitrofurantoin (NF), were investigated in rat and human suspended and sandwich-cultured hepatocytes (SCH). In suspended rat hepatocytes, S-sulfone and S-sulfide inhibited Na+-dependent TC initial uptake (IC50 of 24.9 ± 6.4 and 12.5 ± 1.8 μM, respectively) and Na+-independent E217G initial uptake (IC50 of 12.1 ± 1.6 and 6.3 ± 0.3 μM, respectively). In rat SCH, sulindac metabolites (100 μM) decreased the in vitro biliary clearance (Clbiliary) of TC, E217G, and NF by 38 to 83%, 81 to 97%, and 33 to 57%, respectively; S-sulfone and S-sulfide also decreased the TC and NF biliary excretion index by 39 to 55%. In suspended human hepatocytes, S-sulfone and S-sulfide inhibited Na+-dependent TC initial uptake (IC50 of 42.2 and 3.1 μM, respectively); S-sulfide also inhibited the TC Clbiliary in human SCH. Sulindac/metabolites markedly inhibited hepatic uptake and biliary excretion of E217G by 51 to 100% in human SCH. In conclusion, sulindac and metabolites are potent inhibitors of the uptake and biliary clearance of bile acids in rat and human hepatocytes and also inhibit substrates of rat breast cancer resistance protein, rat and human organic anion-transporting polypeptides, and human multidrug resistance-associated protein 2. Inhibition of multiple hepatic transport proteins by sulindac/metabolites may play an important role in clinically significant sulindac-mediated drug–drug interactions and/or liver injury. PMID:20430841

  3. Sulindac and its metabolites inhibit multiple transport proteins in rat and human hepatocytes.

    PubMed

    Lee, Jin Kyung; Paine, Mary F; Brouwer, Kim L R

    2010-08-01

    Sulindac is a commonly used nonsteroidal anti-inflammatory drug. This study tested the hypothesis that sulindac-mediated drug-drug interactions and/or hepatotoxicity may be caused, in part, by inhibition of proteins responsible for the hepatic transport of drugs and/or bile acids by sulindac and/or sulindac metabolites [sulindac sulfone (S-sulfone) and sulindac sulfide (S-sulfide)]. The uptake and excretion of model substrates, [(3)H]taurocholate (TC), [(3)H]estradiol 17-beta-glucuronide (E217G), and nitrofurantoin (NF), were investigated in rat and human suspended and sandwich-cultured hepatocytes (SCH). In suspended rat hepatocytes, S-sulfone and S-sulfide inhibited Na(+)-dependent TC initial uptake (IC(50) of 24.9 +/- 6.4 and 12.5 +/- 1.8 microM, respectively) and Na(+)-independent E217G initial uptake (IC(50) of 12.1 +/- 1.6 and 6.3 +/- 0.3 microM, respectively). In rat SCH, sulindac metabolites (100 microM) decreased the in vitro biliary clearance (Cl(biliary)) of TC, E217G, and NF by 38 to 83%, 81 to 97%, and 33 to 57%, respectively; S-sulfone and S-sulfide also decreased the TC and NF biliary excretion index by 39 to 55%. In suspended human hepatocytes, S-sulfone and S-sulfide inhibited Na(+)-dependent TC initial uptake (IC(50) of 42.2 and 3.1 microM, respectively); S-sulfide also inhibited the TC Cl(biliary) in human SCH. Sulindac/metabolites markedly inhibited hepatic uptake and biliary excretion of E217G by 51 to 100% in human SCH. In conclusion, sulindac and metabolites are potent inhibitors of the uptake and biliary clearance of bile acids in rat and human hepatocytes and also inhibit substrates of rat breast cancer resistance protein, rat and human organic anion-transporting polypeptides, and human multidrug resistance-associated protein 2. Inhibition of multiple hepatic transport proteins by sulindac/metabolites may play an important role in clinically significant sulindac-mediated drug-drug interactions and/or liver injury.

  4. PARP-1 inhibition influences the oxidative stress response of the human lens

    PubMed Central

    Smith, Andrew J.O.; Ball, Simon S.R.; Bowater, Richard P.; Wormstone, I. Michael

    2016-01-01

    Poly(ADP-ribose) polymerase-1 (PARP-1) is best characterised for its involvement in DNA repair. PARP-1 activity is also linked to cell fate, confounding its roles in maintaining genome integrity. The current study assessed the functional roles of PARP-1 within human lens cells in response to oxidative stress. The human lens epithelial cell line FHL124 and whole human lens cultures were used as experimental systems. Hydrogen peroxide (H2O2) was employed to induce oxidative stress and cell death was assessed by LDH release. The functional influence of PARP-1 was assessed using targeted siRNA and chemical inhibition (by AG14361). Immunocytochemistry and western blotting were used to assess PARP-1 expression and the alkaline comet assay determined the levels of DNA strand breaks. PARP-1 was generally observed in the cell nucleus in both the FHL124 cell line and whole human lenses. PARP-1 inhibition rendered FHL124 cells more susceptible to H2O2-induced DNA strand breaks. Interestingly, reduction of PARP-1 activity significantly inhibited H2O2-induced cell death relative to control cells. Inhibition of PARP-1 in whole human lenses resulted in a reduced level of lens opacity and cell death following exposure to H2O2 relative to matched pair controls. Thus, we show that PARP-1 could play a role in the fate of human lens cells, and these first observations in human lenses suggest that it could impact on lens opacity. Further studies are required to elucidate the regulatory processes that give rise to these effects. PMID:26990173

  5. CO{sub 2} impairs peroxynitrite-mediated inhibition of human caspase-3

    SciTech Connect

    Ascenzi, Paolo . E-mail: ascenzi@uniroma3.it; Marino, Maria; Menegatti, Enea

    2006-10-13

    Peroxynitrite (ONOO{sup -}) is a transient powerful oxidant produced in vivo as the reaction of nitrogen monoxide ({sup ?}NO) with superoxide (O2?-). The peroxynitrite reactivity is modulated by carbon dioxide (CO{sub 2}) which enhances the peroxynitrite-mediated nitration of aromatics and partially impairs the oxidation of thiols. Here, the effect of CO{sub 2} on the peroxynitrite-mediated inhibition of human caspase-3, the execution enzyme of the apoptotic cascade, is reported. Peroxynitrite inhibits the catalytic activity of human caspase-3 by oxidizing the S{gamma} atom of the Cys catalytic residue. In the absence of CO{sub 2}, 1.0 equivalent of peroxynitrite inactivates 1.0 equivalent of human caspase-3. In the presence of the physiological concentration of CO{sub 2} (=1.3x10{sup -3}M), 1.0 equivalent of peroxynitrite inactivates only 0.38 equivalents of human caspase-3. Peroxynitrite affects the k{sub cat} value of the human caspase-3 catalyzed hydrolysis of N-acetyl-Asp-Glu-Val-Asp-7-amido-4-methylcoumarin, without altering K{sub m}. Both in the absence and presence of CO{sub 2}, the reducing agent dithiothreitol does not prevent human caspase-3 inhibition by peroxynitrite and does not reverse the peroxynitrite-induced inactivation of human caspase-3. These results represent First evidence for modulation of peroxynitrite-mediated inhibition of cysteine proteinase action by CO{sub 2}, supporting the role of CO{sub 2} in fine tuning of cell processes (e.g., apoptosis)

  6. Potent inhibition of cytochrome P450 2B6 by sibutramine in human liver microsomes.

    PubMed

    Bae, Soo Hyeon; Kwon, Min Jo; Choi, Eu Jin; Zheng, Yu Fen; Yoon, Kee Dong; Liu, Kwang-Hyeon; Bae, Soo Kyung

    2013-09-05

    The present study was performed to evaluate the potency and specificity of sibutramine as an inhibitor of the activities of nine human CYP isoforms in liver microsomes. Using a cocktail assay, the effects of sibutramine on specific marker reactions of the nine CYP isoforms were measured in human liver microsomes. Sibutramine showed potent inhibition of CYP2B6-mediated bupropion 6-hydroxylation with an IC50 value of 1.61μM and Ki value of 0.466μM in a competitive manner at microsomal protein concentrations of 0.25mg/ml; this was 3.49-fold more potent than the typical CYP2B6 inhibitor thio-TEPA (Ki=1.59μM). In addition, sibutramine slightly inhibited CYP2C19 activity (Ki=16.6μM, noncompetitive inhibition) and CYP2D6 activity (Ki=15.7μM, noncompetitive inhibition). These observations indicated 35.6- and 33.7-fold decreases in inhibition potency, respectively, compared with that of CYP2B6 by sibutramine. However, no inhibition of CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2D6, or CYP2E1 activities was observed. In addition, the CYP2B6 inhibitory potential of sibutramine was enhanced at a lower microsomal protein concentration of 0.05mg/ml. After 30min preincubation of human liver microsomes with sibutramine in the presence of NADPH, no shift in IC50 was observed in terms of inhibition of the activities of the nine CYPs, suggesting that sibutramine is not a time-dependent inactivator. These observations suggest that sibutramine is a selective and potent inhibitor of CYP2B6 in vitro, whereas inhibition of other CYPs is substantially lower. These in vitro data support the use of sibutramine as a well-known inhibitor of CYP2B6 for routine screening of P450 reversible inhibition when human liver microsomes are used as the enzyme source.

  7. In vitro inhibition and induction of human liver cytochrome p450 enzymes by milnacipran.

    PubMed

    Paris, Brandy L; Ogilvie, Brian W; Scheinkoenig, Julie A; Ndikum-Moffor, Florence; Gibson, Remi; Parkinson, Andrew

    2009-10-01

    Milnacipran (Savella) inhibits both norepinephrine and serotonin reuptake and is distinguished by a nearly 3-fold greater potency in inhibiting norepinephrine reuptake in vitro compared with serotonin. We evaluated the ability of milnacipran to inhibit and induce human cytochrome P450 enzymes in vitro. In human liver microsomes, milnacipran did not inhibit CYP1A2, 2B6, 2C8, 2C9, 2C19, or 2D6 (IC(50) >or= 100 microM); whereas, a comparator with dual reuptake properties [duloxetine (Cymbalta)] inhibited CYP2D6 (IC(50) = 7 microM) and CYP2B6 (IC(50) = 15 microM) with a relatively high potency. Milnacipran inhibited CYP3A4/5 in a substrate-dependent manner (i.e., midazolam 1'-hydroxylation IC(50) approximately 30 microM; testosterone 6beta-hydroxylation IC(50) approximately 100 microM); whereas, duloxetine inhibited both CYP3A4/5 activities with equal potency (IC(50) = 37 and 38 microM, respectively). Milnacipran produced no time-dependent inhibition (<10%) of P450 activity, whereas duloxetine produced time-dependent inhibition of CYP1A2, 2B6, 2C19, and 3A4/5. To evaluate P450 induction, freshly isolated human hepatocytes (n = 3) were cultured and treated once daily for 3 days with milnacipran (3, 10, and 30 microM), after which microsomal P450 activities were measured. Whereas positive controls (omeprazole, phenobarbital, and rifampin) caused anticipated P450 induction, milnacipran had minimal effect on CYP1A2, 2C8, 2C9, or 2C19 activity. The highest concentration of milnacipran (30 microM; >10 times plasma C(max)) produced 2.6- and 2.2-fold increases in CYP2B6 and CYP3A4/5 activity (making it 26 and 34% as effective as phenobarbital and rifampin, respectively). Given these results, milnacipran is not expected to cause clinically significant P450 inhibition or induction.

  8. Generation and characterization of small single domain antibodies inhibiting human tumor necrosis factor receptor 1.

    PubMed

    Steeland, Sophie; Puimège, Leen; Vandenbroucke, Roosmarijn E; Van Hauwermeiren, Filip; Haustraete, Jurgen; Devoogdt, Nick; Hulpiau, Paco; Leroux-Roels, Geert; Laukens, Debby; Meuleman, Philip; De Vos, Martine; Libert, Claude

    2015-02-13

    The cytokine TNF is a well known drug target for several inflammatory diseases such as Crohn disease. Despite the great success of TNF blockers, therapy could be improved because of high costs and side effects. Selective inhibition of TNF receptor (TNFR) 1 signaling holds the potential to greatly reduce the pro-inflammatory activity of TNF, thereby preserving the advantageous immunomodulatory signals mediated by TNFR2. We generated a selective human TNFR1 inhibitor based on Nanobody (Nb) technology. Two anti-human TNFR1 Nbs were linked with an anti-albumin Nb to generate Nb Alb-70-96 named "TNF Receptor-One Silencer" (TROS). TROS selectively binds and inhibits TNF/TNFR1 and lymphotoxin-α/TNFR1 signaling with good affinity and IC50 values, both of which are in the nanomolar range. Surface plasmon resonance analysis reveals that TROS competes with TNF for binding to human TNFR1. In HEK293T cells, TROS strongly reduces TNF-induced gene expression, like IL8 and TNF, in a dose-dependent manner; and in ex vivo cultured colon biopsies of CD patients, TROS inhibits inflammation. Finally, in liver chimeric humanized mice, TROS antagonizes inflammation in a model of acute TNF-induced liver inflammation, reflected in reduced human IL8 expression in liver and reduced IL6 levels in serum. These results demonstrate the considerable potential of TROS and justify the evaluation of TROS in relevant disease animal models of both acute and chronic inflammation and eventually in patients.

  9. Active and inhibited human catalase structures: ligand and NADPH binding and catalytic mechanism.

    PubMed

    Putnam, C D; Arvai, A S; Bourne, Y; Tainer, J A

    2000-02-11

    Human catalase is an heme-containing peroxisomal enzyme that breaks down hydrogen peroxide to water and oxygen; it is implicated in ethanol metabolism, inflammation, apoptosis, aging and cancer. The 1. 5 A resolution human enzyme structure, both with and without bound NADPH, establishes the conserved features of mammalian catalase fold and assembly, implicates Tyr370 as the tyrosine radical, suggests the structural basis for redox-sensitive binding of cognate mRNA via the catalase NADPH binding site, and identifies an unexpectedly substantial number of water-mediated domain contacts. A molecular ruler mechanism based on observed water positions in the 25 A-long channel resolves problems for selecting hydrogen peroxide. Control of water-mediated hydrogen bonds by this ruler selects for the longer hydrogen peroxide and explains the paradoxical effects of mutations that increase active site access but lower catalytic rate. The heme active site is tuned without compromising peroxide binding through a Tyr-Arg-His-Asp charge relay, arginine residue to heme carboxylate group hydrogen bonding, and aromatic stacking. Structures of the non-specific cyanide and specific 3-amino-1,2, 4-triazole inhibitor complexes of human catalase identify their modes of inhibition and help reveal the catalytic mechanism of catalase. Taken together, these resting state and inhibited human catalase structures support specific, structure-based mechanisms for the catalase substrate recognition, reaction and inhibition and provide a molecular basis for understanding ethanol intoxication and the likely effects of human polymorphisms. Copyright 2000 Academic Press.

  10. Piceatannol, a natural trans-stilbene compound, inhibits human glyoxalase I.

    PubMed

    Takasawa, Ryoko; Akahane, Haruka; Tanaka, Hikari; Shimada, Nami; Yamamoto, Takayuki; Uchida-Maruki, Hiroko; Sai, Masahiko; Yoshimori, Atsushi; Tanuma, Sei-Ichi

    2017-03-01

    Human glyoxalase I (GLO I), a rate-limiting enzyme for detoxification of methylglyoxal (MG), a by-product of glycolysis, is known to be a potential therapeutic target for cancer. Here, we searched new scaffolds from natural compounds for designing novel GLO I inhibitors and found trans-stilbene scaffold. We examined the inhibitory abilities to human GLO I of commercially available trans-stilbene compounds. Among them, piceatannol was found to have the most potent inhibitory activity against human GLO I. Piceatannol could inhibit the proliferation of human lung cancer NCI-H522 cells, which are dependent on GLO I for survival, in a dose- and time-dependent manner. In addition, piceatannol more significantly inhibited the proliferation of NCI-H522 cells than that of NCI-H460 cells, which are less dependent on GLO I. Importantly, overexpression of GLO I in NCI-H522 cells resulted in less sensitive to the antiproliferative activity of piceatannol. Taken together, this is the first report demonstrating that piceatannol inhibits GLO I activity and the GLO I-dependent proliferation of cancer cells. Furthermore, we determined a pharmacophore for novel inhibitors of human GLO I by computational simulation analyses of the binding mode of piceatannol to the enzyme hot spot in the active site. We suggest that piceatannol is a possible lead compound for the development of novel GLO I inhibitory anticancer drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Cadmium(II) inhibition of human uracil-DNA glycosylase by catalytic water supplantation

    NASA Astrophysics Data System (ADS)

    Gokey, Trevor; Hang, Bo; Guliaev, Anton B.

    2016-12-01

    Toxic metals are known to inhibit DNA repair but the underlying mechanisms of inhibition are still not fully understood. DNA repair enzymes such as human uracil-DNA glycosylase (hUNG) perform the initial step in the base excision repair (BER) pathway. In this work, we showed that cadmium [Cd(II)], a known human carcinogen, inhibited all activity of hUNG at 100 μM. Computational analyses based on 2 μs equilibrium, 1.6 μs steered molecular dynamics (SMD), and QM/MM MD determined that Cd(II) ions entered the enzyme active site and formed close contacts with both D145 and H148, effectively replacing the catalytic water normally found in this position. Geometry refinement by density functional theory (DFT) calculations showed that Cd(II) formed a tetrahedral structure with D145, P146, H148, and one water molecule. This work for the first time reports Cd(II) inhibition of hUNG which was due to replacement of the catalytic water by binding the active site D145 and H148 residues. Comparison of the proposed metal binding site to existing structural data showed that D145:H148 followed a general metal binding motif favored by Cd(II). The identified motif offered structural insights into metal inhibition of other DNA repair enzymes and glycosylases.

  12. Novel quinolone CHM-1 induces apoptosis and inhibits metastasis in a human osterogenic sarcoma cell line.

    PubMed

    Hsu, Shu-Chun; Yang, Jai-Sing; Kuo, Chao-Lin; Lo, Chyi; Lin, Jing-Pin; Hsia, Te-Chun; Lin, Jen-Jyh; Lai, Kuang-Chi; Kuo, Hsiu-Maan; Huang, Li-Jiau; Kuo, Sheng-Chu; Wood, W Gibson; Chung, Jing-Gung

    2009-12-01

    Novel 2-phenyl-4-quinolone compounds have potent cytotoxic effects on different human cancer cell lines. In this study, we examined anticancer activity and mechanisms of 20-fluoro-6,7-methylenedioxy-2-phenyl-4-quinolone (CHM-1) in human osterogenic sarcoma U-2 OS cells. CHM-1-induced apoptosis was determined by flow cytometric analysis, DAPI staining, Comet assay, and caspase inhibitors. CHM-1-inhibited cell migration and invasion was assessed by a wound healing assay, gelatin zymography, and a Transwell assay. The mechanisms of CHM-1 effects on apoptosis and metastasis signaling pathways were studied using Western blotting and gene expression. CHM-1 induced G2/M arrest and apoptosis at an IC(50) (3 microM) in U-2 OS cells and caspase-3, -8, and -9 were activated. Caspase inhibitors increased cell viability after exposure to CHM-1. CHM-1-induced apoptosis was associated with enhanced ROS generation, DNA damage, decreased DeltaPsi(m) levels, and promotion of mitochondrial cytochrome c release. CHM-1 stimulated mRNA expression of caspase-3, -8, and -9, AIF, and Endo G. In addition, CHM-1 inhibited cell metastasis at a low concentration (<3 microM). CHM-1 inhibited the cell metastasis through the inhibition of MMP-2, -7, and -9. CHM-1 also decreased the levels of MAPK signaling pathways before leading to the inhibition of MMPs. In summary, CHM-1 is a potent inducer of apoptosis, which plays a role in the anticancer activity of CHM-1.

  13. The Aryl Hydrocarbon Receptor Ligand ITE Inhibits TGFβ1-Induced Human Myofibroblast Differentiation

    PubMed Central

    Lehmann, Geniece M.; Xi, Xia; Kulkarni, Ajit A.; Olsen, Keith C.; Pollock, Stephen J.; Baglole, Carolyn J.; Gupta, Shikha; Casey, Ann E.; Huxlin, Krystel R.; Sime, Patricia J.; Feldon, Steven E.; Phipps, Richard P.

    2011-01-01

    Fibrosis can occur in any human tissue when the normal wound healing response is amplified. Such amplification results in fibroblast proliferation, myofibroblast differentiation, and excessive extracellular matrix deposition. Occurrence of these sequelae in organs such as the eye or lung can result in severe consequences to health. Unfortunately, medical treatment of fibrosis is limited by a lack of safe and effective therapies. These therapies may be developed by identifying agents that inhibit critical steps in fibrotic progression; one such step is myofibroblast differentiation triggered by transforming growth factor-β1 (TGFβ1). In this study, we demonstrate that TGFβ1-induced myofibroblast differentiation is blocked in human fibroblasts by a candidate endogenous aryl hydrocarbon receptor (AhR) ligand 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE). Our data show that ITE disrupts TGFβ1 signaling by inhibiting the nuclear translocation of Smad2/3/4. Although ITE functions as an AhR agonist, and biologically persistent AhR agonists, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, cause severe toxic effects, ITE exhibits no toxicity. Interestingly, ITE effectively inhibits TGFβ1-driven myofibroblast differentiation in AhR−/− fibroblasts: Its ability to inhibit TGFβ1 signaling is AhR independent. As supported by the results of this study, the small molecule ITE inhibits myofibroblast differentiation and may be useful clinically as an antiscarring agent. PMID:21406171

  14. Synthetic sialylphosphatidylethanolamine derivatives bind to human influenza A viruses and inhibit viral infection.

    PubMed

    Guo, C T; Wong, C H; Kajimoto, T; Miura, T; Ida, Y; Juneja, L R; Kim, M J; Masuda, H; Suzuki, T; Suzuki, Y

    1998-11-01

    We synthesized the sialylphosphatidylethanolamine (sialyl PE) derivatives Neu5Ac-PE, (Neu5Ac)2-PE, Neu5Ac-PE (amide) and Neu5Ac-PE (methyl). We examined the anti-viral effects of the derivatives on human influenza A virus infection by ELISA/virus-binding, hemagglutination inhibition, hemolysis inhibition and neutralization assays. The sialyl PE derivatives that we examined bound to A/Aichi/2/68, A/Singapore/1/57 and A/Memphis/1/71 strains of H3N2 subtype, but not to A/PR/8/34 strain of H1N1 subtype. The derivatives inhibited viral hemagglutination and hemolysis of human erythrocytes with A/Aichi/2/68 and A/Singapore/1/57 (H3N2), but not with A/PR/8/34 (H1N1). The inhibitory activity of the (Neu5Ac)2-PE derivative was the strongest of all sialyl PE derivatives (IC50, 35 microM to 40 microM). Sialyl PE derivatives also inhibited the infection of A/Aichi/2/68 in MDCK cells. Complete inhibition was observed at a concentration between 0.3 to 1.3 mM. IC50 of (Neu5Ac)2-PE was 15 microM in A/Aichi/2/68 strain. Taken together, the synthetic sialyl PE derivatives may be effective reagents against infection of some types of influenza A viruses.

  15. Purification, inhibition and mechanistic studies of Clostridium histolyticum and human neutrophil collagenases

    SciTech Connect

    Mookhtiar, K.A.

    1986-01-01

    The specific collagenase stored in the granules of human neutrophils has been purified by a simple, reproducible method. A sensitive, accurate and convenient assay for tissue collagenases has been developed to aid the purification. This assay, which is based on the hydrolysis of (/sup 3/H)acetylated rat tail tendon type I collagen, has also enabled the inhibition of this enzyme to be studied quantitatively. The purified enzyme has very high specific activity towards type I collagen and is devoid of other contaminating proteolytic activities. It is a zinc metalloproteinase that requires calcium ions for activity. In addition, it contains essential lysine, tyrosine and carboxyl residues within the active site. The types of compounds that have been found to be good inhibitors for other zinc metalloproteinases also inhibit both the human neutrophil and the class I and class II Clostridial collageneases. The Clostridial enzymes are strongly inhibited by phosphonoamidates and ketone analogs that contain collagen-like sequences. This pattern of inhibition suggests a remarkable similarity between the mechanism of action of these collagenases and other well studied zinc metalloproteinases. The inhibition data also suggest the possible use of these inhibitors as pharmaceuticals and as affinity ligands for the purification of the collagenases. In fact, the use of the ketone analogs to purify the class I and class II Clostridial collagenases from crude mixtures has been successfully demonstrated.

  16. Inhibition of Src family kinases with dasatinib blocks migration and invasion of human melanoma cells.

    PubMed

    Buettner, Ralf; Mesa, Tania; Vultur, Adina; Lee, Frank; Jove, Richard

    2008-11-01

    Src family kinases (SFK) are involved in regulating a multitude of biological processes, including cell adhesion, migration, proliferation, and survival, depending on the cellular context. Therefore, although SFKs are currently being investigated as potential targets for treatment strategies in various cancers, the biological responses to inhibition of SFK signaling in any given tumor type are not predictable. Dasatinib (BMS-354825) is a dual Src/Abl kinase inhibitor with potent antiproliferative activity against hematologic malignancies harboring activated BCR-ABL. In this study, we show that dasatinib blocks migration and invasion of human melanoma cells without affecting proliferation and survival. Moreover, dasatinib completely inhibits SFK kinase activity at low nanomolar concentrations in all eight human melanoma cell lines investigated. In addition, two known downstream targets of SFKs, focal adhesion kinase and Crk-associated substrate (p130(CAS)), are inhibited with similar concentrations and kinetics. Consistent with inhibition of these signaling pathways and invasion, dasatinib down-regulates expression of matrix metalloproteinase-9. We also provide evidence that dasatinib directly inhibits kinase activity of the EphA2 receptor tyrosine kinase, which is overexpressed and/or overactive in many solid tumors, including melanoma. Thus, SFKs and downstream signaling are implicated as having key roles in migration and invasion of melanoma cells.

  17. Cadmium(II) inhibition of human uracil-DNA glycosylase by catalytic water supplantation

    PubMed Central

    Gokey, Trevor; Hang, Bo; Guliaev, Anton B.

    2016-01-01

    Toxic metals are known to inhibit DNA repair but the underlying mechanisms of inhibition are still not fully understood. DNA repair enzymes such as human uracil-DNA glycosylase (hUNG) perform the initial step in the base excision repair (BER) pathway. In this work, we showed that cadmium [Cd(II)], a known human carcinogen, inhibited all activity of hUNG at 100 μM. Computational analyses based on 2 μs equilibrium, 1.6 μs steered molecular dynamics (SMD), and QM/MM MD determined that Cd(II) ions entered the enzyme active site and formed close contacts with both D145 and H148, effectively replacing the catalytic water normally found in this position. Geometry refinement by density functional theory (DFT) calculations showed that Cd(II) formed a tetrahedral structure with D145, P146, H148, and one water molecule. This work for the first time reports Cd(II) inhibition of hUNG which was due to replacement of the catalytic water by binding the active site D145 and H148 residues. Comparison of the proposed metal binding site to existing structural data showed that D145:H148 followed a general metal binding motif favored by Cd(II). The identified motif offered structural insights into metal inhibition of other DNA repair enzymes and glycosylases. PMID:27974818

  18. Cimicifuga foetida L. inhibited human respiratory syncytial virus in HEp-2 and A549 cell lines.

    PubMed

    Wang, Kuo Chih; Chang, Jung San; Chiang, Lien Chai; Lin, Chun Ching

    2012-01-01

    Human respiratory syncytial virus (HRSV) causes serious pediatric infection of the lower respiratory tract without effective therapeutic modality. Sheng-Ma-Ge-Gen-Tang (SMGGT; Shoma-kakkon-to) has been proven to be effective at inhibiting HRSV-induced plaque formation, and Cimicifuga foetida is the major constituent of SMGGT. We tested the hypothesis that C. foetida effectively inhibited the cytopathic effects of HRSV by a plaque reduction assay in both human upper (HEp2) and lower (A549) respiratory tract cell lines. Its ability to stimulate anti-viral cytokines was evaluated by an enzyme-linked immunosorbent assay (ELISA). C. foetida dose-dependently inhibited HRSV-induced plaque formation (p < 0.0001) before and after viral inoculation, especially in A549 cells (p < 0.0001). C. foetida dose-dependently inhibited viral attachment (p < 0.0001) and could increase heparins effect on viral attachment. In addition, C. foetida time-dependently and dose-dependently (p < 0.0001) inhibited HRSV internalization. C. foetida could stimulate epithelial cells to secrete IFN-β to counteract viral infection. However, C. foetida did not stimulate TNF-α secretion. Therefore, C. foetida could be useful in managing HRSV infection. This is the first evidence to support that C. foetida possesses antiviral activity.

  19. Human astrocytes inhibit Cryptococcus neoformans growth by a nitric oxide-mediated mechanism

    PubMed Central

    1994-01-01

    Cryptococcus neoformans is an opportunistic fungus that causes life- threatening meningoencephalitis in 5-10% of patients with acquired immune deficiency syndrome. Cryptococcal meningoencephalitis is characterized by a lymphohistiocytic infiltrate, accumulation of encapsulated forms of C. neoformans, and varying degrees of glial reaction. Little is known about the contribution of endogenous central nervous system cells to the pathogenesis of cryptococcal infections. In this study, we investigated the role of astrocytes as potential effector cells against C. neoformans. Primary cultures of human fetal astrocytes, activated with interleukin 1 beta plus interferon gamma inhibited the growth of C. neoformans. The inhibition of C. neoformans growth was paralleled by production of nitrite, and reversed by the inhibitors of nitric oxide (NO.) synthase, NG-methyl-mono-arginine and NG-nitro-arginine methyl ester. The results suggest a novel function for human astrocytes in host defence and provide a precedent for the use of NO. as an antimicrobial effector molecule by human cells. PMID:8006595

  20. Potent inhibition of human neutrophil activations by bractelactone, a novel chalcone from Fissistigma bracteolatum

    SciTech Connect

    Wu, Yang-Chang; Sureshbabu, Munisamy; Fang, Yao-Ching; Wu, Yi-Hsiu; Lan, Yu-Hsuan; Chang, Fang-Rong; Chang, Ya-Wen; Hwang, Tsong-Long

    2013-02-01

    Fissistigma bracteolatum is widely used in traditional medicine to treat inflammatory diseases. However, its active components and mechanisms of action remain unclear. In this study, (3Z)-6,7-dihydroxy-4-methoxy-3-(phenylmethylidene)-5-(3-phenylpropanoyl) -1-benzofuran-2(3H) (bractelactone), a novel chalcone from F. bracteolatum, showed potent inhibitory effects against superoxide anion (O{sub 2}{sup ·−}) production, elastase release, and CD11b expression in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced human neutrophils. However, bractelactone showed only weak inhibition of phorbol myristate acetate-caused O{sub 2}{sup ·−} production. The peak cytosolic calcium concentration ([Ca{sup 2+}]{sub i}) was unaltered by bractelactone in FMLP-induced neutrophils, but the decay time of [Ca{sup 2+}]{sub i} was significantly shortened. In a calcium-free solution, changes in [Ca{sup 2+}]{sub i} caused by the addition of extracellular Ca{sup 2+} were inhibited by bractelactone in FMLP-activated cells. In addition, bractelactone did not alter the phosphorylation of p38 MAPK, ERK, JNK, or AKT or the concentration of cAMP. These results suggest that bractelactone selectively inhibits store-operated calcium entry (SOCE). In agreement with this concept, bractelactone suppressed sustained [Ca{sup 2+}]{sub i} changes in thapsigargin-activated neutrophils. Furthermore, bractelactone did not alter FMLP-induced formation of inositol 1,4,5-triphosphate. Taken together, our results demonstrate that the anti-inflammatory effects of bractelactone, an active ingredient of F. bracteolatum, in human neutrophils are through the selective inhibition of SOCE. Highlights: ► Bractelactone isolated from Fissistigma bracteolatum. ► Bractelactone inhibited FMLP-induced human neutrophil activations. ► Bractelactone had no effect on IP3 formation. ► Bractelactone did not alter MAPKs, AKT, and cAMP pathways. ► Bractelactone inhibited store-operated calcium entry.

  1. Inhibition of human anthracycline reductases by emodin - A possible remedy for anthracycline resistance.

    PubMed

    Hintzpeter, Jan; Seliger, Jan Moritz; Hofman, Jakub; Martin, Hans-Joerg; Wsol, Vladimir; Maser, Edmund

    2016-02-15

    The clinical application of anthracyclines, like daunorubicin and doxorubicin, is limited by two factors: dose-related cardiotoxicity and drug resistance. Both have been linked to reductive metabolism of the parent drug to their metabolites daunorubicinol and doxorubicinol, respectively. These metabolites show significantly less anti-neoplastic properties as their parent drugs and accumulate in cardiac tissue leading to chronic cardiotoxicity. Therefore, we aimed to identify novel and potent natural inhibitors for anthracycline reductases, which enhance the anticancer effect of anthracyclines by preventing the development of anthracycline resistance. Human enzymes responsible for the reductive metabolism of daunorubicin were tested for their sensitivity towards anthrachinones, in particular emodin and anthraflavic acid. Intense inhibition kinetic data for the most effective daunorubicin reductases, including IC50- and Ki-values, the mode of inhibition, as well as molecular docking, were compiled. Subsequently, a cytotoxicity profile and the ability of emodin to reverse daunorubicin resistance were determined using multiresistant A549 lung cancer and HepG2 liver cancer cells. Emodin potently inhibited the four main human daunorubicin reductases in vitro. Further, we could demonstrate that emodin is able to synergistically sensitize human cancer cells towards daunorubicin at clinically relevant concentrations. Therefore, emodin may yield the potential to enhance the therapeutic effectiveness of anthracyclines by preventing anthracycline resistance via inhibition of the anthracycline reductases. In symphony with its known pharmacological properties, emodin might be a compound of particular interest in the management of anthracycline chemotherapy efficacy and their adverse effects.

  2. Dimethyl sulfoxide at high concentrations inhibits non-selective cation channels in human erythrocytes.

    PubMed

    Nardid, Oleg A; Schetinskey, Miroslav I; Kucherenko, Yuliya V

    2013-03-01

    Dimethyl sulfoxide (DMSO), a by-product of the pulping industry, is widely used in biological research, cryobiology and medicine. On cellular level DMSO was shown to suppress NMDA-AMPA channels activation, blocks Na+ channel activation and attenuates Ca2+ influx (Lu and Mattson 2001). In the present study we explored the whole-cell patch-clamp to examine the acute effect of high concentrations of DMSO (0.1-2 mol/l) on cation channels activity in human erythrocytes. Acute application of DMSO (0.1-2 mol/l) dissolved in Cl--containing saline buffer solution significantly inhibited cation conductance in human erythrocytes. Inhibition was concentration-dependent and had an exponential decay profile. DMSO (2 mol/l) induced cation inhibition in Cl-- containing saline solutions of: 40.3 ± 3.9% for K+, 35.4 ± 3.1% for Ca2+ and 47.4 ± 1.9% for NMDG+. Substitution of Cl- with gluconate- increased the inhibitory effect of DMSO on the Na+ current. Inhibitory effect of DMSO was neither due to high permeability of erythrocytes to DMSO nor to an increased tonicity of the bath media since no effect was observed in 2 mol/l glycerol solution. In conclusion, we have shown that high concentrations of DMSO inhibit the non-selective cation channels in human erythrocytes and thus protect the cells against Na+ and Ca2+ overload. Possible mechanisms of DMSO effect on cation conductance are discussed.

  3. Inhibition of human topoisomerase II in vitro by bioactive benzene metabolites.

    PubMed Central

    Frantz, C E; Chen, H; Eastmond, D A

    1996-01-01

    Benzene is a clastogenic and carcinogenic agent that induces acute myelogenous leukemia in humans and multiple of tumors in animals. Previous research has indicated that benzene must first be metabolized to one or more bioactive species to exert its myelotoxic and genotoxic effects. To better understand the possible role of individual benzene metabolites in the leukemogenic process, as well as to further investigate inhibition of topoisomerase II by benzene metabolites, a series of known and putative benzene metabolites, phenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, catechol, 1,2,4-benzenetriol, 1,4-benzoquinone, and trans-trans-muconaldehyde were tested for inhibitory effects in vitro on the human topoisomerase II enzyme. With minor modifications of the standard assay conditions, 1,4-benzoquinone and trans-trans-muconaldehyde were shown to be directly inhibitory, whereas all of the phenolic metabolites were shown to inhibit enzymatic activity following bioactivation using a peroxidase activation system. The majority of compounds tested inhibited topoisomerase II at concentrations at or below 10 microM. These results confirm and expand upon previous findings from our laboratory and indicate that many of the metabolites of benzene could potentially interfere with topoisomerase II. Since other inhibitors of topoisomerase II have been shown to induce leukemia in humans, inhibition of this enzyme by benzene metabolites may also play a role in the carcinogenic effects of benzene. PMID:9118913

  4. Selective Inhibition of Bakuchicin Isolated from Psoralea corylifolia on CYP1A in Human Liver Microsomes.

    PubMed

    Kim, Sun Joo; Oh, Heung Chan; Kim, Youn-Chul; Jeong, Gil-Saeng; Lee, Sangkyu

    2016-01-01

    Bakuchicin is a furanocoumarin isolated from Psoralea corylifolia and shows several biological activities. Although there have been studies on the biological effects of bakuchicin, its modulation potency of CYP activities has not been previously investigated. Here, we investigated the inhibitory effects of bakuchicin on the activities of CYP isoforms by using a cocktail of probe substrates in pooled human liver microsomes (HLMs) and human recombinant cDNA-expressed CYP. Bakuchicin strongly inhibited CYP1A-mediated phenacetin O-deethylation with an IC50 value of 0.43 μM in HLMs. It was confirmed by human recombinant cDNA-expressed CYP1A1 and CYP1A2 with a K i value of 0.11 μM and 0.32 μM, respectively. A Lineweaver-Burk plot indicated that the inhibition mechanism of bakuchicin was competitive inhibition. Overall, this is the first study to investigate the potential CYP1A1 and CYP1A2 inhibition associated with bakuchicin and to report its competitive inhibitory effects on HLMs.

  5. Time-dependent inhibition of human drug metabolizing cytochromes P450 by tricyclic antidepressants

    PubMed Central

    Polasek, Thomas M; Miners, John O

    2008-01-01

    AIMS To investigate time-dependent inhibition (TDI) of human drug metabolizing CYP enzymes by tricyclic antidepressants (TCAs). METHODS CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A/CYP3A4 activities were investigated following co- and preincubation with TCAs using human liver microsomes (HLM) and human recombinant CYP proteins (expressed in Escherichia coli) as the enzyme sources. A two-step incubation method was employed to examine the in vitro mechanism-based inactivation (MBI) criteria. Potential metabolite–intermediate complex (MIC) formation was studied by spectral analysis. RESULTS TCAs generally exhibited significant TDI of recombinant CYP1A2, CYP2C19 and CYP2D6 (>10% positive inhibition differences between co- and preincubation conditions). TDI of recombinant CYP2C9 was minor (<10%), and was minor or absent in experiments utilizing recombinant CYP3A4 or HLM as the enzyme sources. Where observed, TDI of recombinant CYP occurred via alkylamine MIC formation, but evidence to support similar behaviour in HLM was limited. Indeed, only secondary amine TCAs reduced the apparent P450 content of HLM (3–6%) consistent with complexation. As a representative TCA, nortriptyline fulfilled the in vitro MBI criteria using recombinant CYP2C19 and CYP3A4 (KI and kinact values of 4 µm and 0.19 min−1, and 70 µm and 0.06 min−1), but not with the human liver microsomal enzymes. CONCLUSIONS TCAs appear to have minimal potential for MBI of human liver microsomal CYP enzymes involved in drug metabolism. HLM and recombinant CYP (expressed in E. coli) are not equivalent enzyme sources for evaluating the TDI associated with some drugs. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Much of the literature evidence for mechanism-based inactivation (MBI) of CYP by tricyclic antidepressants is limited to studies in rat liver microsomes. One report from this laboratory characterized MBI of human recombinant CYP2C8 by nortriptyline. WHAT THIS STUDY ADDS Tricyclic antidepressants form

  6. Mechanism of inhibition of human secretory phospholipase A2 by flavonoids: rationale for lead design

    NASA Astrophysics Data System (ADS)

    Lättig, Jens; Böhl, Markus; Fischer, Petra; Tischer, Sandra; Tietböhl, Claudia; Menschikowski, Mario; Gutzeit, Herwig O.; Metz, Peter; Pisabarro, M. Teresa

    2007-08-01

    The human secretory phospholipase A2 group IIA (PLA2-IIA) is a lipolytic enzyme. Its inhibition leads to a decrease in eicosanoids levels and, thereby, to reduced inflammation. Therefore, PLA2-IIA is of high pharmacological interest in treatment of chronic diseases such as asthma and rheumatoid arthritis. Quercetin and naringenin, amongst other flavonoids, are known for their anti-inflammatory activity by modulation of enzymes of the arachidonic acid cascade. However, the mechanism by which flavonoids inhibit Phospholipase A2 (PLA2) remained unclear so far. Flavonoids are widely produced in plant tissues and, thereby, suitable targets for pharmaceutical extractions and chemical syntheses. Our work focuses on understanding the binding modes of flavonoids to PLA2, their inhibition mechanism and the rationale to modify them to obtain potent and specific inhibitors. Our computational and experimental studies focused on a set of 24 compounds including natural flavonoids and naringenin-based derivatives. Experimental results on PLA2-inhibition showed good inhibitory activity for quercetin, kaempferol, and galangin, but relatively poor for naringenin. Several naringenin derivatives were synthesized and tested for affinity and inhibitory activity improvement. 6-(1,1-dimethylallyl)naringenin revealed comparable PLA2 inhibition to quercetin-like compounds. We characterized the binding mode of these compounds and the determinants for their affinity, selectivity, and inhibitory potency. Based on our results, we suggest C(6) as the most promising position of the flavonoid scaffold to introduce chemical modifications to improve affinity, selectivity, and inhibition of PLA2-IIA by flavonoids.

  7. Nicotine, cotinine, and anabasine inhibit aromatase in human trophoblast in vitro.

    PubMed Central

    Barbieri, R L; Gochberg, J; Ryan, K J

    1986-01-01

    Epidemiologic studies suggest that women who smoke have lower endogenous estrogen than nonsmokers. To explore the possible link between cigarette smoking and decreased endogenous estrogens, we have examined the effects of constituents of tobacco on estrogen production in human choriocarcinoma cells and term placental microsomes. In choriocarcinoma cell cultures, nicotine, cotinine (a major metabolite of nicotine), and anabasine (a minor component of cigarette tobacco) all inhibited androstenedione conversion to estrogen in a dose-dependent fashion. Removal of nicotine, cotinine, and anabasine from the culture medium resulted in the complete reversal of the inhibition of aromatase. In the choriocarcinoma cell cultures, a supraphysiologic concentration of androstenedione (73 microM) in the culture medium blocked the inhibition of aromatase caused by nicotine, cotinine, and anabasine. In preparations of term placental microsomes, nicotine, cotinine, and anabasine inhibited the conversion of testosterone to estrogen. Kinetic analysis demonstrated the inhibition to be competitive with respect to the substrate. These findings suggest that some nicotinic alkaloids directly inhibit aromatase. This mechanism may explain, in part, the decreased estrogen observed in women who smoke. PMID:3711333

  8. Effect of black raspberry extract in inhibiting NFkappa B dependent radioprotection in human breast cancer cells.

    PubMed

    Madhusoodhanan, Rakhesh; Natarajan, Mohan; Singh, Jamunarani Veeraraghavan Nisha; Jamgade, Ambarish; Awasthi, Vibhudutta; Anant, Shrikant; Herman, Terence S; Aravindan, Natarajan

    2010-01-01

    Black raspberry extracts (RSE) have been shown to inhibit cancer cell growth and stimulate apoptosis. Also, studies have demonstrated that RSE inhibits transcriptional regulators including NFkappa B. Accordingly, we investigated the effect of RSE in inhibiting radiation (IR) induced NFkappa B mediated radioprotection in breast adenocarcinoma cells. MCF-7 cells were exposed to IR (2Gy), treated with RSE (0.5, 1.0, 2.0 micro g/ml) or treated with RSE (1.0 micro g/ml) followed by IR exposure, and harvested after 1, 3, 6, 24, 48, and 72 h. NFkappa B DNA-binding activity was measured by EMSA and phosphorylated Ikappa Balpha by immunoblotting. Expression of IAP1, IAP2, XIAP and survivin were measured by QPCR and immunoblotting. Cell survival was measured using MTT assay and cell death using Caspase-3/7 activity. Effect of RSE on IR induced MnSOD, TNFalpha, IL-1alpha and MnSOD activity was also determined. RSE inhibited NFkappa B activity in a dose-dependent manner. Also, RSE inhibited IR-induced sustained activation of NFkappa B, and NFkappa B regulated IAP1, IAP2, XIAP, and survivin. In addition, RSE inhibited IR-induced TNFalpha, IL-1alpha, and MnSOD levels and MnSOD activity. RSE suppressed cell survival and enhanced cell death. These results suggest that RSE may act as a potent radiosensitizer by overcoming the effects of NFkappa B mediated radioprotection in human breast cancer cells.

  9. Pirfenidone inhibits p38-mediated generation of procoagulant microparticles by human alveolar epithelial cells.

    PubMed

    Neri, Tommaso; Lombardi, Stefania; Faìta, Francesca; Petrini, Silvia; Balìa, Cristina; Scalise, Valentina; Pedrinelli, Roberto; Paggiaro, Pierluigi; Celi, Alessandro

    2016-08-01

    Pirfenidone is a drug recently approved for idiopathic pulmonary fibrosis but its mechanisms of action are partially unknown. We have previously demonstrated that the airways of patients with idiopathic pulmonary fibrosis contain procoagulant microparticles that activate coagulation factor X to its active form, Xa, a proteinase that signals fibroblast growth and differentiation, thus potentially contributing to the pathogenesis of the disease. We also reported that in vitro exposure of human alveolar cells to H2O2 causes microparticle generation. Since p38 activation is involved in microparticle generation in some cell models and p38 inhibition is one of the mechanisms of action of pirfenidone, we investigated the hypothesis that H2O2-induced generation of microparticles by alveolar cells is dependent on p38 phosphorylation and is inhibited by pirfenidone. H2O2 stimulation of alveolar cells caused p38 phosphorylation that was inhibited by pirfenidone. The drug also inhibited H2O2 induced microparticle generation as assessed by two independent methods (solid phase thrombin generation and flow cytometry). The shedding of microparticle-bound tissue factor activity was also inhibited by pirfenidone. Inhibition of p38-mediated generation of procoagulant microparticle is a previously unrecognized mechanism of action of the antifibrotic drug, pirfenidone.

  10. Sensory gating, inhibition control and gamma oscillations in the human somatosensory cortex

    PubMed Central

    Cheng, Chia-Hsiung; Chan, Pei-Ying S.; Niddam, David M.; Tsai, Shang-Yueh; Hsu, Shih-Chieh; Liu, Chia-Yih

    2016-01-01

    Inhibiting the responses to irrelevant stimuli is an essential component of human cognitive function. Pre-attentive auditory sensory gating (SG), an attenuated neural activation to the second identical stimulus, has been found to be related to the performance of higher-hierarchical brain function. However, it remains unclear whether other cortical regions, such as somatosensory cortex, also possess similar characteristics, or if such a relationship is modality-specific. This study used magnetoencephalography to record neuromagnetic responses to paired-pulse electrical stimulation to median nerve in 22 healthy participants. Somatosensory SG ratio and cortical brain oscillations were obtained and compared with the behavioral performance of inhibition control, as evaluated by somatosensory and auditory Go-Nogo tasks. The results showed that somatosensory P35m SG ratio correlated with behavioral performance of inhibition control. Such relationship was also established in relation to the auditory Go-Nogo task. Finally, a higher frequency value of evoked gamma oscillations was found to relate to a better somatosensory SG ability. In conclusion, our data provided an empirical link between automatic cortical inhibition and behavioral performance of attentive inhibition control. This study invites further research on the relationships among gamma oscillations, neurophysiological indices, and behavioral performance in clinical populations in terms of SG or cortical inhibition. PMID:26843358

  11. Sensory gating, inhibition control and gamma oscillations in the human somatosensory cortex.

    PubMed

    Cheng, Chia-Hsiung; Chan, Pei-Ying S; Niddam, David M; Tsai, Shang-Yueh; Hsu, Shih-Chieh; Liu, Chia-Yih

    2016-02-04

    Inhibiting the responses to irrelevant stimuli is an essential component of human cognitive function. Pre-attentive auditory sensory gating (SG), an attenuated neural activation to the second identical stimulus, has been found to be related to the performance of higher-hierarchical brain function. However, it remains unclear whether other cortical regions, such as somatosensory cortex, also possess similar characteristics, or if such a relationship is modality-specific. This study used magnetoencephalography to record neuromagnetic responses to paired-pulse electrical stimulation to median nerve in 22 healthy participants. Somatosensory SG ratio and cortical brain oscillations were obtained and compared with the behavioral performance of inhibition control, as evaluated by somatosensory and auditory Go-Nogo tasks. The results showed that somatosensory P35m SG ratio correlated with behavioral performance of inhibition control. Such relationship was also established in relation to the auditory Go-Nogo task. Finally, a higher frequency value of evoked gamma oscillations was found to relate to a better somatosensory SG ability. In conclusion, our data provided an empirical link between automatic cortical inhibition and behavioral performance of attentive inhibition control. This study invites further research on the relationships among gamma oscillations, neurophysiological indices, and behavioral performance in clinical populations in terms of SG or cortical inhibition.

  12. BET bromodomain inhibition rescues erythropoietin differentiation of human erythroleukemia cell line UT7

    SciTech Connect

    Goupille, Olivier; Penglong, Tipparat; Lefevre, Carine; Granger, Marine; Kadri, Zahra; Fucharoen, Suthat; Maouche-Chretien, Leila; Leboulch, Philippe; Chretien, Stany

    2012-12-07

    Highlights: Black-Right-Pointing-Pointer UT7 erythroleukemia cells are known to be refractory to differentiate. Black-Right-Pointing-Pointer Brief JQ1 treatment initiates the first steps of erythroid differentiation program. Black-Right-Pointing-Pointer Engaged UT7 cells then maturate in the presence of erythropoietin. Black-Right-Pointing-Pointer Sustained JQ1 treatment inhibits both proliferation and erythroid differentiation. -- Abstract: Malignant transformation is a multistep process requiring oncogenic activation, promoting cellular proliferation, frequently coupled to inhibition of terminal differentiation. Consequently, forcing the reengagement of terminal differentiation of transformed cells coupled or not with an inhibition of their proliferation is a putative therapeutic approach to counteracting tumorigenicity. UT7 is a human leukemic cell line able to grow in the presence of IL3, GM-CSF and Epo. This cell line has been widely used to study Epo-R/Epo signaling pathways but is a poor model for erythroid differentiation. We used the BET bromodomain inhibition drug JQ1 to target gene expression, including that of c-Myc. We have shown that only 2 days of JQ1 treatment was required to transitory inhibit Epo-induced UT7 proliferation and to restore terminal erythroid differentiation. This study highlights the importance of a cellular erythroid cycle break mediated by c-Myc inhibition before initiation of the erythropoiesis program and describes a new model for BET bromodomain inhibitor drug application.

  13. Syntheses and in vitro evaluations of uncharged reactivators for human acetylcholinesterase inhibited by organophosphorus nerve agents.

    PubMed

    Renou, Julien; Mercey, Guillaume; Verdelet, Tristan; Păunescu, Emilia; Gillon, Emilie; Arboléas, Mélanie; Loiodice, Mélanie; Kliachyna, Maria; Baati, Rachid; Nachon, Florian; Jean, Ludovic; Renard, Pierre-Yves

    2013-03-25

    Organophosphorus nerve agents (OPNAs) are highly toxic compounds that represent a threat to both military and civilian populations. They cause an irreversible inhibition of acetylcholinesterase (AChE), by the formation of a covalent P-O bond with the catalytic serine. Among the present treatment of nerve agents poisoning, pyridinium and bis-pyridinium aldoximes are used to reactivate this inhibited enzyme but these compounds do not readily cross the blood brain barrier (BBB) due to their permanent cationic charge and thus cannot efficiently reactivate cholinesterases in the central nervous system (CNS). In this study, a series of seven new uncharged oximes reactivators have been synthesized and their in vitro ability to reactivate VX and tabun-inhibited human acetylcholinesterase (hAChE) has been evaluated. The dissociation constant K(D) of inhibited enzyme-oxime complex, the reactivity rate constant kr and the second order reactivation rate constant k(r2) have been determined and have been compared to reference oximes HI-6, Obidoxime and 2-Pralidoxime (2-PAM). Regarding the reactivation of VX-inhibited hAChE, all compounds show a better reactivation potency than those of 2-PAM, nevertheless they are less efficient than obidoxime and HI-6. Moreover, one of seven described compounds presents an ability to reactivate tabun-inhibited hAChE equivalent to those of 2-PAM. Crown Copyright © 2012. Published by Elsevier Ireland Ltd. All rights reserved.

  14. The multi-targeted kinase inhibitor sorafenib inhibits human cytomegalovirus replication.

    PubMed

    Michaelis, Martin; Paulus, Christina; Löschmann, Nadine; Dauth, Stephanie; Stange, Elisabeth; Doerr, Hans Wilhelm; Nevels, Michael; Cinatl, Jindrich

    2011-03-01

    Human cytomegalovirus (HCMV) is a major pathogen in immunocompromised individuals. Here, non-toxic concentrations of the anti-cancer kinase inhibitor sorafenib were shown to inhibit replication of different HCMV strains (including a ganciclovir-resistant strain) in different cell types. In contrast to established anti-HCMV drugs, sorafenib inhibited HCMV major immediate early promoter activity and HCMV immediate early antigen (IEA) expression. Sorafenib is known to inhibit Raf. Comparison of sorafenib with the MEK inhibitor U0126 suggested that sorafenib inhibits HCMV IEA expression through inhibition of Raf but independently of signaling through the Raf downstream kinase MEK 1/2. In concordance, siRNA-mediated depletion of Raf but not of MEK-reduced IEA expression. In conclusion, sorafenib diminished HCMV replication in clinically relevant concentrations and inhibited HCMV IEA expression, a pathophysiologically relevant event that is not affected by established anti-HCMV drugs. Moreover, we demonstrated for the first time that Raf activation is involved in HCMV IEA expression.

  15. Mechanism of inhibition of the human sirtuin enzyme SIRT3 by nicotinamide: computational and experimental studies.

    PubMed

    Guan, Xiangying; Lin, Ping; Knoll, Eric; Chakrabarti, Raj

    2014-01-01

    Sirtuins are key regulators of many cellular functions including cell growth, apoptosis, metabolism, and genetic control of age-related diseases. Sirtuins are themselves regulated by their cofactor nicotinamide adenine dinucleotide (NAD+) as well as their reaction product nicotinamide (NAM), the physiological concentrations of which vary during the process of aging. Nicotinamide inhibits sirtuins through the so-called base exchange pathway, wherein rebinding of the reaction product to the enzyme accelerates the reverse reaction. We investigated the mechanism of nicotinamide inhibition of human SIRT3, the major mitochondrial sirtuin deacetylase, in vitro and in silico using experimental kinetic analysis and Molecular Mechanics-Poisson Boltzmann/Generalized Born Surface Area (MM-PB(GB)SA) binding affinity calculations with molecular dynamics sampling. Through experimental kinetic studies, we demonstrate that NAM inhibition of SIRT3 involves apparent competition between the inhibitor and the enzyme cofactor NAD+, contrary to the traditional characterization of base exchange as noncompetitive inhibition. We report a model for base exchange inhibition that relates such kinetic properties to physicochemical properties, including the free energies of enzyme-ligand binding, and estimate the latter through the first reported computational binding affinity calculations for SIRT3:NAD+, SIRT3:NAM, and analogous complexes for Sir2. The computational results support our kinetic model, establishing foundations for quantitative modeling of NAD+/NAM regulation of mammalian sirtuins during aging and the computational design of sirtuin activators that operate through alleviation of base exchange inhibition.

  16. Sulforaphane, a cruciferous vegetable-derived isothiocyanate, inhibits protein synthesis in human prostate cancer cells.

    PubMed

    Wiczk, Aleksandra; Hofman, Dagmara; Konopa, Grażyna; Herman-Antosiewicz, Anna

    2012-08-01

    Sulforaphane (SFN) is a compound derived from cruciferous plants. Its anticancer properties have been demonstrated both, in cancer cell lines as well as tumors in animal models. It has been shown that SFN inhibits cell proliferation, induces apoptosis, autophagy, and sensitizes cancer cells to therapies. As induction of catabolic processes is often related to perturbation in protein synthesis we aimed to investigate the impact of SFN on this process in PC-3 human prostate cancer cells. In the present study we show that SFN inhibits protein synthesis in PC-3 cells in a dose- and time-dependent manner which is accompanied by a decreased phosphorylation of mTOR substrates. Translation inhibition is independent of mitochondria-derived ROS as it is observed in PC-3 derivatives devoid of functional mitochondrial respiratory chain (Rho0 cells). Although SFN affects mitochondria and slightly decreases glycolysis, the ATP level is maintained on the level characteristic for control cells. Inhibition of protein synthesis might be a protective response of prostate cancer cells to save energy. However, translation inhibition contributes to the death of PC-3 cells due to decreased level of a short-lived protein, survivin. Overexpression of this anti-apoptotic factor protects PC-3 cells against SFN cytotoxicity. Protein synthesis inhibition by SFN is not restricted to prostate cancer cells as we observed similar effect in SKBR-3 breast cancer cell line. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Cryptotanshinone and dihydrotanshinone I exhibit strong inhibition towards human liver microsome (HLM)-catalyzed propofol glucuronidation.

    PubMed

    Cong, Ming; Hu, Cui-Min; Cao, Yun-Feng; Fang, Zhong-Ze; Tang, Shu-Hong; Wang, Jia-Rui; Luo, Jun-Sheng

    2013-03-01

    Danshen is one of the most famous herbs in the world, and more and more danshen-prescribed drugs interactions have been reported in recent years. Evaluation of inhibition potential of danshen's major ingredients towards UDP-glucuronosyltransferases (UGTs) will be helpful for understanding detailed mechanisms for danshen-drugs interaction. Therefore, the aim of the present study is to investigate the inhibitory situation of cryptotanshinone and dihydrotanshinone I towards UGT enzyme-catalyzed propofol glucuronidation. In vitro the human liver microsome (HLM) incubation system was used, and the results showed that cryptotanshinone and dihydrotanshinone I exhibited dose-dependent inhibition towards HLM-catalyzed propofol glucuronidation. Dixon plot and Lineweaver-Burk plot showed that the inhibition type was best fit to competitive inhibition type for both cryptotanshinone and dihydrotanshinone I. The second plot using the slopes from the Lineweaver-Burk plot versus the concentrations of cryptotanshinone or dihydrotanshinone I was employed to calculate the inhibition parameters (Ki) to be 0.4 and 1.7μM, respectively. Using the reported maximum plasma concentration (Cmax), the altered in vivo exposure of propofol increased by 10% and 8.2% for the co-administration of dihydrotanshinone I and cryptotanshinone, respectively. All these results indicated the possible danshen-propofol interaction due to the inhibition of dihydrotanshinone I and cryptotanshinone towards the glucuronidation reaction of propofol.

  18. Adenovirus Vectors Block Human Immunodeficiency Virus–1 Replication in Human Alveolar Macrophages by Inhibition of the Long Terminal Repeat

    PubMed Central

    Kaner, Robert J.; Santiago, Francisco; Rahaghi, Franck; Michaels, Elizabeth; Moore, John P.; Crystal, Ronald G.

    2010-01-01

    Heterologous viruses may transactivate or suppress human immunodeficiency virus (HIV)–1 replication. An adenovirus type 5 gene transfer vector (Ad5) HIV-1 vaccine was recently evaluated in a clinical trial, without efficacy. In this context, it is relevant to ask what effect Ad vectors have on HIV-1 replication, particularly in cells that are part of the innate immune system. Infection of HIV-1–infected human alveolar macrophages (AMs) obtained from HIV-1+ individuals with an Ad vector containing no transgene (AdNull) resulted in dose-responsive inhibition of endogenous HIV-1 replication. HIV-1 replication in normal AMs infected with HIV-1 in vitro was inhibited by AdNull with a similar dose response. Ad reduced AM HIV-1 replication up to 14 days after HIV-1 infection. Fully HIV-1–infected AMs were treated with 3′-azido-3′-deoxythymidine, after which Ad infection still inhibited HIV-1 replication, suggesting a postentry step was affected. Substantial HIV-1 DNA was still produced after Ad infection, as quantified by TaqMan real-time PCR, suggesting that the replication block occurred after reverse transcription. AdNull blocked HIV-1 long terminal repeat (LTR) transcription, as assessed by an vesicular stomatitis virus G protein pseudotyped HIV-1 LTR luciferase construct. The formation of HIV-1 DNA integrated into the host chromosome was not inhibited by Ad, as quantified by a two-step TaqMan real-time PCR assay, implying a postintegration block to HIV-1 replication. These data indicate that Ad vectors are inhibitory to HIV-1 replication in human AMs based, in part, on their ability to inhibit LTR-driven transcription. PMID:19805482

  19. Gly429 is the major determinant of uncompetitive inhibition of human germ cell alkaline phosphatase by L-leucine.

    PubMed Central

    Hummer, C; Millán, J L

    1991-01-01

    The catalytic activity of human placental alkaline phosphatase (PLAP) and germ cell alkaline phosphatase (GCAP) can be inhibited, through an uncompetitive mechanism, by L-Phe. GCAP is also selectively inhibited by L-Leu. Site-directed mutagenesis of five of the 12 residues which are different in PLAP and GCAP revealed that Gly429 is the primary determinant of GCAP inhibition by L-Leu, and Ser84 and Leu297 play a modulatory role in the inhibition. PMID:2001256

  20. Human single-chain variable fragment antibody inhibits macrophage migration inhibitory factor tautomerase activity.

    PubMed

    Tarasuk, Mayuri; Poungpair, Ornnuthchar; Ungsupravate, Duangporn; Bangphoomi, Kunan; Chaicumpa, Wanpen; Yenchitsomanus, Pa-Thai

    2014-03-01

    Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine, secreted from a variety of immune cells, that regulates innate and adaptive immune responses. Elevation of MIF levels in plasma correlates with the severity of inflammatory diseases in humans. Inhibition of MIF or its tautomerase activity ameliorates disease severity by reducing inflammatory responses. In this study, the human single-chain variable fragment (HuScFv) antibody specific to MIF was selected from the human antibody phage display library by using purified recombinant full-length human MIF (rMIF) as the target antigen. Monoclonal HuScFv was produced from phage-transformed bacteria and tested for their binding activities to rMIF by indirect enzyme-linked immunosorbent assay as well as to native MIF by western blot analysis and immunofluorescence assay. The HuScFv with highest binding signal to rMIF also inhibited the tautomerase activities of both rMIF and native MIF in human monoblastic leukemia (U937) cells in a dose-dependent manner. Mimotope searching and molecular docking concordantly demonstrated that the HuScFv interacted with Lys32 and Ile64 in the MIF tautomerase active site. To the best of our knowledge, this is the first study to focus on MIF-specific fully-human antibody fragment with a tautomerase-inhibitory effect that has potential to be developed as anti-inflammatory biomolecules for human use.

  1. Selective inhibition of leukotriene C/sub 4/ synthesis in human neutrophils by ethacrynic acid

    SciTech Connect

    Leung, K.H.

    1986-05-29

    Addition of glutathione S-transferase inhibitors, ethyacrynic acid (ET), caffeic acid (CA), and ferulic acid (FA) to human neutrophils led to inhibition of leukotriene C/sub 4/ (LTC/sub 4/) synthesis induced by calcium ionophore A23187. ET is the most specific of these inhibitors for it had little effect on LTB/sub 4/, PGE/sub 2/, and 5-HETE synthesis. The inhibition of LTC/sub 4/ was irreversible and time dependent. ET also had little effect on /sup 3/H-AA release from A23187-stimulated neutrophils.

  2. Human immunodeficiency virus has an aspartic-type protease that can be inhibited by pepstatin A.

    PubMed Central

    Seelmeier, S; Schmidt, H; Turk, V; von der Helm, K

    1988-01-01

    The protease encoded by the human immunodeficiency virus (HIV) processes the viral gag and gag-pol protein precursor by posttranslational cleavage. In this study we have demonstrated by site-specific mutagenesis (Asp----Thr) and by pepstatin A inhibition that the recombinant HIV protease is an aspartic-type protease. Furthermore, incubation of HIV-infected H9 cells with pepstatin A inhibited part of the intracellular processing of the HIV gag protein yet had no apparent toxicity on HIV-infected cells during 48 hr of incubation. Images PMID:3045820

  3. Grepafloxacin inhibits tumor necrosis factor-alpha-induced interleukin-8 expression in human airway epithelial cells.

    PubMed

    Hashimoto, S; Matsumoto, K; Gon, Y; Maruoka, S; Hayashi, S; Asai, Y; Machino, T; Horie, T

    2000-01-01

    We examined the effect of grepafloxacin (GPFX), a new fluoroquinolone antimicrobial agent, on interleukin-8 (IL-8) expression in tumor necrosis factor-alpha (TNF-alpha)-stimulated human airway epithelial cells (AEC). GPFX inhibited IL-8 protein production as well as mRNA expression in a concentration-dependent manner (2.5 - 25 micro g/ml), but the inhibition of IL-8 expression by corresponding concentrations of GPFX to serum and airway lining fluids was not complete. We discuss the modulatory effect of GPFX on IL-8 production in the context of its efficacy on controlling chronic airway inflammatory diseases.

  4. Kinetics of the inhibition of human leucocyte elastase by eglin from the leech Hirudo medicinalis.

    PubMed Central

    Baici, A; Seemüller, U

    1984-01-01

    The rate constants for the inhibition of human leucocyte elastase by eglin from the leech Hirudo medicinalis were determined by using a pre-steady-state kinetic approach. kon and koff for complex-formation and dissociation were 1 X 10(6)M-1 X S-1 and 8 X 10(-4)S-1 respectively. Ki was calculated as the ratio koff/kon = 8 X 10(-10)M, the binding of eglin to elastase was reversible and the inhibition mechanism was of the fully competitive type. The mechanistic properties of the system and the biological significance of the rate constants are discussed. PMID:6562888

  5. Inhibition of platelet (/sup 3/H)- imipramine binding by human plasma protein fractions

    SciTech Connect

    Strijewski, A.; Chudzik, J.; Tang, S.W.

    1988-01-01

    Inhibition of high-affinity (/sup 3/H)-imipramine binding to platelet membranes by human plasma fractions and isolated plasma proteins was investigated. Several plasma proteins were found to contribute to the observed apparent inhibition and this contribution was assessed in terms of inhibitor units. Alpha/sub 1/ acid glycoprotein, high density and low density lipoprotein, IgG and ..cap alpha../sub 1/-antitrypsin were identified as effective non-specific inhibitors. Alpha-1-acid glycoprotein was confirmed to be the most potent plasma protein inhibitor. Cohn fractions were evaluated for the presence of the postulated endocoid of (/sup 3/H)-imipramine binding site.

  6. Evaluation of monoquaternary pyridinium oximes potency to reactivate tabun-inhibited human acetylcholinesterase.

    PubMed

    Odzak, Renata; Calić, Maja; Hrenar, Tomica; Primozic, Ines; Kovarik, Zrinka

    2007-04-20

    Monoquaternary N-benzyl-4-hydroxyiminomethylpyridinium bromide (Py-4-H) and its analogous with diverse substituents introduced into the phenyl ring (Py-4-CH(3), Py-4-Br, Py-4-Cl and Py-4-NO(2)) were synthesized in order to examine their potency as reactivators of tabun-inhibited human erythrocyte acetylcholinesterase (AChE; EC 3.1.1.7). Within 24h, the reactivation of tabun-inhibited AChE reached 80% with Py-4-CH(3), Py-4-Br and Py-4-Cl, 40% with Py-4-NO(2), and 30% with Py-4-H. The overall reactivation rate constants were up to 5.0min(-1)M(-1). All oximes inhibited human AChE reversibly, and the inhibition potency increased in the following order Py-4-Brhuman AChE have been proposed by flexible ligand docking with AutoDock 3.0. Analyses of the obtained complexes revealed the presence of numerous hydrogen bonds and close contacts between the oximes and the residues in the active site. Final docked energies predicted correctly the relative order of the inhibition potency of compounds (except in the case of Py-4-CH(3)) as well as the most probable orientation of the best reactivator, Py-4-Br, which can result in an attack on the phosphorus atom of the tabun-phosphorylated human AChE.

  7. Inhibition of 5-lipoxygenase and leukotriene C4 synthase in human blood cells by thymoquinone.

    PubMed

    Mansour, Mahmoud; Tornhamre, Susanne

    2004-10-01

    Black cumin seed, Nigella sativa L., and its oils have traditionally been used for the treatment of asthma and other inflammatory diseases. Thymoquinone (TQ) has been proposed to be one of the major active components of the drug. Since leukotrienes (LTs) are important mediators in asthma and inflammatory processes, the effects of TQ on leukotriene formation were studied in human blood cells. TQ provoked a significant concentration-dependent inhibition of both LTC4 and LTB4 formation from endogenous substrate in human granulocyte suspensions with IC50 values of 1.8 and 2.3 microM, respectively, at 15 min. Major inhibitory effect was on the 5-lipoxygenase activity (IC50 3 microM) as evidenced by suppressed conversion of exogenous arachidonic acid into 5-hydroxy eicosatetraenoic acid (5HETE) in sonicated polymorphonuclear cell suspensions. In addition, TQ induced a significant inhibition of LTC4 synthase activity, with an IC50 of 10 microM, as judged by suppressed transformation of exogenous LTA4 into LTC4. In contrast, the drug was without any inhibitory effect on LTA4 hydrolase activity. When exogenous LTA4 was added to intact or sonicated platelet suspensions preincubated with TQ, a similar inhibition of LTC4 synthase activity was observed as in human granulocyte suspensions. The unselective protein kinase inhibitor, staurosporine failed to prevent inhibition of LTC4 synthase activity induced by TQ. The findings demonstrate that TQ potently inhibits the formation of leukotrienes in human blood cells. The inhibitory effect was dose- and time-dependent and was exerted on both 5-lipoxygenase and LTC4 synthase activity.

  8. Acute effects of cocaine and cannabis on response inhibition in humans: an ERP investigation.

    PubMed

    Spronk, Desirée B; De Bruijn, Ellen R A; van Wel, Janelle H P; Ramaekers, Johannes G; Verkes, Robbert J

    2016-11-01

    Substance abuse has often been associated with alterations in response inhibition in humans. Not much research has examined how the acute effects of drugs modify the neurophysiological correlates of response inhibition, or how these effects interact with individual variation in trait levels of impulsivity and novelty seeking. This study investigated the effects of cocaine and cannabis on behavioural and event-related potential (ERP) correlates of response inhibition in 38 healthy drug using volunteers. A double-blind placebo-controlled randomized three-way crossover design was used. All subjects completed a standard Go/NoGo task after administration of the drugs. Compared with a placebo, cocaine yielded improved accuracy, quicker reaction times and an increased prefrontal NoGo-P3 ERP. Cannabis produced opposing results; slower reaction times, impaired accuracy and a reduction in the amplitude of the prefrontal NoGo-P3. Cannabis in addition decreased the amplitude of the parietally recorded P3, while cocaine did not affect this. Neither drugs specifically affected the N2 component, suggesting that pre-motor response inhibitory processes remain unaffected. Neither trait impulsivity nor novelty seeking interacted with drug-induced effects on measures of response inhibition. We conclude that acute drug effects on response inhibition seem to be specific to the later, evaluative stages of response inhibition. The acute effects of cannabis appeared less specific to response inhibition than those of cocaine. Together, the results show that the behavioural effects on response inhibition are reflected in electrophysiological correlates. This study did not support a substantial role of vulnerability personality traits in the acute intoxication stage.

  9. In vitro inhibition of human papillomavirus following use of a carrageenan-containing vaginal gel.

    PubMed

    Novetsky, Akiva P; Keller, Marla J; Gradissimo, Ana; Chen, Zigui; Morgan, Stephanie L; Xue, Xiaonan; Strickler, Howard D; Fernández-Romero, José A; Burk, Robert; Einstein, Mark H

    2016-11-01

    To assess in vitro efficacy of Divine 9, a carrageenan-based vaginal lubricant that is being studied as a microbicide to inhibit HPV16 pseudovirus (PsV) infection. Sexually active US women between 19 and 35years without prior HPV vaccination or cervical intraepithelial neoplasia were instructed to use Divine 9 vaginally with an applicator either before sex only or before and after intercourse. Women who applied a single dose of gel returned for cervicovaginal lavage (CVL) collection 1, 4 or 8-12h after intercourse versus those who applied gel before and after intercourse returned 1, 4 or 8-12h after the second gel dose. Carrageenan concentrations were assessed using an ELISA assay and the inhibitory activity was assessed using a PsV-based neutralization assay against HPV16 infection. Carrageenan concentrations and the percentage of PsV16 inhibition were compared using the Wilcoxon rank sum test. Thirteen women were enrolled and thirty specimens from different time-points were assessed. 87% of CVL samples had detectable carrageenans with levels decreasing over time from intercourse. 93% of CVL samples had detectable PsV16 inhibition with median inhibition of 97.5%. PsV16 inhibition decreased over time, but remained high, with median inhibition of 98.1%, 97.4% and 83.4% at 1, 4 and 8-12h, respectively. Higher carrageenan concentrations were associated with higher levels of PsV16 inhibition (rho=0.69). This is the first report of a human study investigating in vitro HPV inhibition of a carrageenan-based vaginal lubricant with CVL collected after sexual intercourse. We demonstrate excellent efficacy in preventing PsV16 infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Inhibition of ZEB1 expression induces redifferentiation of adult human β cells expanded in vitro.

    PubMed

    Sintov, Elad; Nathan, Gili; Knoller, Sarah; Pasmanik-Chor, Metsada; Russ, Holger A; Efrat, Shimon

    2015-08-12

    In-vitro expansion of functional adult human β-cells is an attractive approach for generating insulin-producing cells for transplantation. However, human islet cell expansion in culture results in loss of β-cell phenotype and epithelial-mesenchymal transition (EMT). This process activates expression of ZEB1 and ZEB2, two members of the zinc-finger homeobox family of E-cadherin repressors, which play key roles in EMT. Downregulation of ZEB1 using shRNA in expanded β-cell-derived (BCD) cells induced mesenchymal-epithelial transition (MET), β-cell gene expression, and proliferation attenuation. In addition, inhibition of ZEB1 expression potentiated redifferentiation induced by a combination of soluble factors, as judged by an improved response to glucose stimulation and a 3-fold increase in the fraction of C-peptide-positive cells to 60% of BCD cells. Furthermore, ZEB1 shRNA led to increased insulin secretion in cells transplanted in vivo. Our findings suggest that the effects of ZEB1 inhibition are mediated by attenuation of the miR-200c target genes SOX6 and SOX2. These findings, which were reproducible in cells derived from multiple human donors, emphasize the key role of ZEB1 in EMT in cultured BCD cells and support the value of ZEB1 inhibition for BCD cell redifferentiation and generation of functional human β-like cells for cell therapy of diabetes.

  11. Inhibition of lipid peroxidation, cyclooxygenase enzyme and human tumor cell proliferation by compounds in herbal water.

    PubMed

    Liu, Yunbao; Mulabagal, Vanisree; Bowen-Forbes, Camille S; Aviayan, Rejanish; Nair, Muraleedharan G

    2009-09-01

    A powdered mixture of dried herbs, "Panamrutham", is sold in India for the preparation of "herbal drinking water". The hot water extract of this herbal mixture gave lipid peroxidation (LPO), cyclo-oxygenase (COX-1 and -2) enzyme and human tumor cell proliferation inhibitory activities between 25 and 250 microg/mL. The bioassay-guided purification of the water extract afforded a novel compound (1), along with phenolics (2, 4, 6, and 7) and sesquiterpenoids (3 and 5). The isolates were evaluated for LPO, COX-1 and -2 enzyme and human tumor cell proliferation inhibitory activities. At 25 microg/mL, compounds 1-7 inhibited LPO by 22-73% and COX-1 and -2 enzymes by 3-14% and 14-74%, respectively. Compounds 5 and 6 at 25 microg/mL showed growth inhibition of colon, gastric, lung, breast and central nervous system human tumor cell lines by 60 and 67, 43 and 60, 24 and 64, 34 and 65, 6 and 27%, respectively. Compounds 2, 4 and 7 displayed weak or moderate growth inhibition of colon, gastric and breast human tumor cell lines. This is the first report on the LPO inhibitory activities of compounds 1 and 3-7 and the COX and tumor cell proliferation inhibitory activities of compounds 1, 3-5 and 7.

  12. Inhibition of human and rat CYP1A1 enzyme by grapefruit juice compounds.

    PubMed

    Santes-Palacios, Rebeca; Romo-Mancillas, Antonio; Camacho-Carranza, Rafael; Espinosa-Aguirre, Jesús Javier

    2016-09-06

    Cytochrome P4501A1 is involved in the metabolism of carcinogenic polycyclic aromatic hydrocarbons; therefore, its inhibition interferes with the carcinogenesis process induced by these compounds in rats. The human and rat CYP1A1 differ by 21% in amino acid sequence, including the active site of the enzyme; this difference may be an important factor when results obtained using animal models are interpolated to humans. Based on its previously reported CYP inhibitory properties, we studied the effects of two molecules contained within grapefruit juice, naringenin and 6',7'-dihydroxybergamottin, on human and rat CYP1A1 activity. For this purpose, the kinetics of inhibition as well as computational simulations were used. Naringenin and 6',7'-dihydroxybergamottin were found to be competitive inhibitors of human and rat CYP1A1. Additionally, naringenin exerted a mixed type inhibition effect on rat CYP1A1. Computational docking showed that inhibitors might block the oxidation of 7-ethoxyresorufin by binding to the CYP1A1 active site. Our results demonstrate the differences in CYP inhibitory mechanisms for the same molecule when CYP from different species are considered. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. In vitro inhibition of Cryptosporidium parvum infection by human monoclonal antibodies.

    PubMed Central

    Elliot, B C; Wisnewski, A V; Johnson, J; Fenwick-Smith, D; Wiest, P; Hamer, D; Kresina, T; Flanigan, T P

    1997-01-01

    Cryptosporidium parvum infection of the small epithelial intestine causes unremitting diarrhea and malabsorption that can lead to chronic and sometimes fatal illness in patients with AIDS. The illness may be ameliorated by passive oral immunoglobulin therapy. The objective of this study was to produce anti-Cryptosporidium human monoclonal antibodies for evaluation as potential therapy. All human monoclonal cell lines that produced C. parvum antibodies were originally generated from the peripheral blood lymphocytes of a human immunodeficiency virus-seronegative woman. She had recovered from C. parvum infection and had a high specific antibody titer. Hybridization of these lymphocytes with a tumor cell line was accomplished by hypo-osmolar electrofusion. Twelve clones were identified by enzyme-linked immunosorbent assay (ELISA) as secreting anti-Cryptosporidium antibodies after the initial hybridization. From the 12 positive clones, two high antibody-secreting clones, 17A and 17B, were maintained in long-term culture. A second hybridization produced two other human monoclonal cell lines, EC5 and BB2. Human monoclonal antibody from the first two cell lines bound to C. parvum sporozoites and oocysts by immunofluorescence. The ability of human monoclonal antibodies to inhibit C. parvum infection in vitro was assessed by using a human enterocyte cell line, HT29.74. The antibodies of the four different human hybridomas inhibited infection by 35 to 68% (P < 0.05) compared to a control irrelevant human monoclonal antibody derived in a similar fashion. Human monoclonal antibodies are candidate molecules for immunotherapy of C. parvum infection. PMID:9284173

  14. Carbonic anhydrase inhibitors: inhibition of human and murine mitochondrial isozymes V with anions.

    PubMed

    Franchi, Marco; Vullo, Daniela; Gallori, Enzo; Antel, Jochen; Wurl, Michael; Scozzafava, Andrea; Supuran, Claudiu T

    2003-09-01

    In addition to sulfonamides, metal complexing anions represent the second class of inhibitors of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). The first inhibition study of the mitochondrial isozyme CA V (of murine and human origin) with anions is reported here. Inhibition data of the cytosolic isozymes CA I and CA II as well as the membrane-bound isozyme CA IV with a large number of anionic species such as halides, pseudohalides, bicarbonate, nitrate, hydrosulfide, arsenate, sulfamate, and sulfamidate and so on, are also provided for comparison. Isozyme V has an inhibition profile by anions completely different to those of CA I and IV, but similar to that of hCA II, which may have interesting physiological consequences. Similarly to hCA II, the mitochondrial isozymes show micro-nanomolar affinity for sulfonamides such as sulfanilamide and acetazolamide.

  15. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L.; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan

    2015-12-01

    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.

  16. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation.

    PubMed

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan

    2015-12-01

    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.

  17. Isoliquiritigenin inhibits cell proliferation and induces apoptosis in human hepatoma cells.

    PubMed

    Hsu, Ya-Ling; Kuo, Po-Lin; Lin, Liang-Tzung; Lin, Chun-Ching

    2005-02-01

    Isoliquiritigenin (4,2',4'-trihydroxychalcone, ISL) is a natural pigment with a simple chalcone structure. In this study, we report the ISL-induced inhibition on the growth of human hepatoma cells (Hep G2) for the first time. The cell growth inhibition achieved by ISL treatment resulted in programmed cell death in a caspase activation-dependent manner, with an IC50 of 10.51 microg/mL. Outcomes of ISL treatment included the up-regulation of IkappaBalpha expression in the cytoplasm, and the decrease of NF-kappaB level as well as its activity in the nucleus. In addition, ISL also suppressed the expression of Bcl-XL and c-IAP1/2 protein, the downstream target molecule of NF-kappaB. These results demonstrated that ISL treatment inhibited the NF-kappaB cell survival-signaling pathway and induced apoptotic cell death in Hep G2 cells.

  18. Malathion-induced inhibition of human plasma cholinesterase studied by the fluorescence spectroscopy method

    NASA Astrophysics Data System (ADS)

    Pavelkić, V. M.; Krinulović, K. S.; Savić, J. Z.; Ilić, M. A.

    2008-05-01

    The in vitro effect of technical grade malathion was assessed via the kinetic parameters of human plasma butyrylcholinesterase (BChE) using N-methylindoxyl acetate as a substrate for BChE. An inhibitor kinetics study demonstrated the existence of a biphasic inhibition curve, indicating high-and low-affinity binding sites of malathion. The IC 50 values as calculated from the experimental inhibition curves were 1.33 × 10-9 and 1.48 × 10-5 M for the high-and low-affinity binding sites, respectively; Hill’s analysis gave 1.29 × 10-9 and 1.38 × 10-6 M. The Cornish-Bowden plots and their secondary plots indicated that the nature of inhibition was of mixed type with the predominant competitive character of both affinity binding sites.

  19. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation

    PubMed Central

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L.; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan

    2016-01-01

    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies. PMID:26587712

  20. A potassium ionophore (Nigericin) inhibits stimulation of human lymphocytes by mitogens

    PubMed Central

    1978-01-01

    Nigericin, an ionophore that exchanges K+ for H+ across most biologic membranes, reversibly inhibited the proliferative response of human lymphocytes to phytohemagglutinin (PHA). Inhibition occurred at nigericin concentrations of 10(-8) M or greater, and only during the early event of mitogenesis. There was no effect if nigericin was added 24 h or later after the initiation of PHA-stimulated cultures. The effect was not the result of toxicity or impaired mitochondrial respiration. At similar concentrations, nigericin also inhibited lymphocyte responses in mixed lymphocyte cultures and to other mitogens including concanavalin A, pokeweed mitogen, and the calcium ionophore A23187. The findings support the view that one or more transmembranous events, mediated by changes in cation flux and/or membrane potential, are critical in the initial stages of lymphocyte mitogenesis. PMID:146727

  1. Protein-protein interface-binding peptides inhibit the cancer therapy target human thymidylate synthase.

    PubMed

    Cardinale, Daniela; Guaitoli, Giambattista; Tondi, Donatella; Luciani, Rosaria; Henrich, Stefan; Salo-Ahen, Outi M H; Ferrari, Stefania; Marverti, Gaetano; Guerrieri, Davide; Ligabue, Alessio; Frassineti, Chiara; Pozzi, Cecilia; Mangani, Stefano; Fessas, Dimitrios; Guerrini, Remo; Ponterini, Glauco; Wade, Rebecca C; Costi, M Paola

    2011-08-23

    Human thymidylate synthase is a homodimeric enzyme that plays a key role in DNA synthesis and is a target for several clinically important anticancer drugs that bind to its active site. We have designed peptides to specifically target its dimer interface. Here we show through X-ray diffraction, spectroscopic, kinetic, and calorimetric evidence that the peptides do indeed bind at the interface of the dimeric protein and stabilize its di-inactive form. The "LR" peptide binds at a previously unknown binding site and shows a previously undescribed mechanism for the allosteric inhibition of a homodimeric enzyme. It inhibits the intracellular enzyme in ovarian cancer cells and reduces cellular growth at low micromolar concentrations in both cisplatin-sensitive and -resistant cells without causing protein overexpression. This peptide demonstrates the potential of allosteric inhibition of hTS for overcoming platinum drug resistance in ovarian cancer.

  2. Dual mechanisms for telomerase inhibition in DLD-1 human colorectal adenocarcinoma cells by polyunsaturated fatty acids.

    PubMed

    Eitsuka, Takahiro; Nakagawa, Kiyotaka; Miyazawa, Teruo

    2004-01-01

    Polyunsaturated fatty acids (PUFAs) have been reported to have antitumor activity. In this study, we have tested whether telomerase might be a target for the antitumor effect of fatty acids using DLD-1 colorectal adenocarcinoma cells. In a cell-free approach, fatty acids were added directly to cell lysates, and we confirmed that increasing fatty acid unsaturation correlates with increased inhibition of telomerase activity. Using a cell culture approach, DLD-1 cells were cultured with fatty acids. In a time and dose dependent manner, EPA and DHA suppressed cellular telomerase activity and the mRNAs encoding hTERT (human telomerase reverse transcriptase) and c-myc. Based on these observations, we suggest that PUFAs inhibit telomerase activity through dual mechanisms: direct inhibition of enzymatic activity and down regulation of hTERT, one of the telomerase components.

  3. Antisense oligodeoxynucleotide against human telomerase reverse transcriptase inhibits the proliferation of Eca-109 esophageal carcinoma cells

    PubMed Central

    FAN, XIANG-KUI; YAN, RUI-HUA; LI, BAO-JIANG; CHEN, XIANG-MING; WEI, LIN; WANG, ZHOU

    2014-01-01

    Previous studies have demonstrated that the growth of tumor cells may be inhibited by antisense oligonucleotides (ASODNs) targeted against human telomerase (hTR) or human telomerase reverse transcriptase (hTERT), resulting in antitumor activity in a wide variety of tumors. However, few studies have investigated the effect of hTERT gene-targeted ASODNs on telomerase activity and cell proliferation in human esophageal cancer. In the present study, an MTT assay was used to determine the growth inhibition rate of Eca-109 cells treated with a hTERT-targeted phosphorothioate-ASODN (PS-ASODN). An inverted microscope was used to observe the morphologic changes of the cells following treatment with 5 μM PS-ASODN for 10 days. Telomerase activity was detected using the silver staining semi-quantitative telomeric repeat amplification protocol (TRAP) assay. Following treatment with the PS-ASODN (1–5 μmol/l), the proliferation of the Eca-109 cells was inhibited. The differences in inhibition rate between the PS-ASODN and blank control groups were statistically significant (P<0.05) when the concentration of the PS-ASODN was ≥2 μmol/l, whereas no statistically significant difference was identified between the non-specific-ASODN and blank control groups. The inhibition rate increased gradually as the concentration of the PS-ASODN increased and with time, suggesting that the PS-ASODN inhibited the growth of Eca-109 cells in a concentration-dependent, time-dependent and sequence-specific manner. The growth rate of the cells incubated with the PS-ASODN was reduced compared with that of the control cells. Cells treated with the PS-ASODN became round, suspended and reduced in size. The PS-ASODN was also found to inhibit telomerase activity. The ability of the PS-ASODN to inhibit the telomerase activity and cell proliferation of the Eca-109 cell line suggests that ASODNs have the potential to be novel therapeutic agents for the treatment of esophageal cancer. PMID:25187833

  4. Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin

    PubMed Central

    Chedik, Lisa; Bruyere, Arnaud; Le Vee, Marc; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Potin, Sophie; Fardel, Olivier

    2017-01-01

    Pyrethroids are widely-used chemical insecticides, to which humans are commonly exposed, and known to alter functional expression of drug metabolizing enzymes. Limited data have additionally suggested that drug transporters, that constitute key-actors of the drug detoxification system, may also be targeted by pyrethroids. The present study was therefore designed to analyze the potential regulatory effects of these pesticides towards activities of main ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, using transporter-overexpressing cells. The pyrethroids allethrin and tetramethrin were found to inhibit various ABC and SLC drug transporters, including multidrug resistance-associated protein (MRP) 2, breast cancer resistance protein (BCRP), organic anion transporter polypeptide (OATP) 1B1, organic anion transporter (OAT) 3, multidrug and toxin extrusion transporter (MATE) 1, organic cation transporter (OCT) 1 and OCT2, with IC50 values however ranging from 2.6 μM (OCT1 inhibition by allethrin) to 77.6 μM (OAT3 inhibition by tetramethrin) and thus much higher than pyrethroid concentrations (in the nM range) reached in environmentally pyrethroid-exposed humans. By contrast, allethrin and tetramethrin cis-stimulated OATP2B1 activity and failed to alter activities of OATP1B3, OAT1 and MATE2-K, whereas P-glycoprotein activity was additionally moderately inhibited. Twelve other pyrethoids used at 100 μM did not block activities of the various investigated transporters, or only moderately inhibited some of them (inhibition by less than 50%). In silico analysis of structure-activity relationships next revealed that molecular parameters, including molecular weight and lipophilicity, are associated with transporter inhibition by allethrin/tetramethrin and successfully predicted transporter inhibition by the pyrethroids imiprothrin and prallethrin. Taken together, these data fully demonstrated that two pyrethoids, i.e., allethrin and tetramethrin, can

  5. Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin.

    PubMed

    Chedik, Lisa; Bruyere, Arnaud; Le Vee, Marc; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Potin, Sophie; Fardel, Olivier

    2017-01-01

    Pyrethroids are widely-used chemical insecticides, to which humans are commonly exposed, and known to alter functional expression of drug metabolizing enzymes. Limited data have additionally suggested that drug transporters, that constitute key-actors of the drug detoxification system, may also be targeted by pyrethroids. The present study was therefore designed to analyze the potential regulatory effects of these pesticides towards activities of main ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, using transporter-overexpressing cells. The pyrethroids allethrin and tetramethrin were found to inhibit various ABC and SLC drug transporters, including multidrug resistance-associated protein (MRP) 2, breast cancer resistance protein (BCRP), organic anion transporter polypeptide (OATP) 1B1, organic anion transporter (OAT) 3, multidrug and toxin extrusion transporter (MATE) 1, organic cation transporter (OCT) 1 and OCT2, with IC50 values however ranging from 2.6 μM (OCT1 inhibition by allethrin) to 77.6 μM (OAT3 inhibition by tetramethrin) and thus much higher than pyrethroid concentrations (in the nM range) reached in environmentally pyrethroid-exposed humans. By contrast, allethrin and tetramethrin cis-stimulated OATP2B1 activity and failed to alter activities of OATP1B3, OAT1 and MATE2-K, whereas P-glycoprotein activity was additionally moderately inhibited. Twelve other pyrethoids used at 100 μM did not block activities of the various investigated transporters, or only moderately inhibited some of them (inhibition by less than 50%). In silico analysis of structure-activity relationships next revealed that molecular parameters, including molecular weight and lipophilicity, are associated with transporter inhibition by allethrin/tetramethrin and successfully predicted transporter inhibition by the pyrethroids imiprothrin and prallethrin. Taken together, these data fully demonstrated that two pyrethoids, i.e., allethrin and tetramethrin, can

  6. Midazolam Induces Cellular Apoptosis in Human Cancer Cells and Inhibits Tumor Growth in Xenograft Mice

    PubMed Central

    Mishra, Siddhartha Kumar; Kang, Ju-Hee; Lee, Chang Woo; Oh, Seung Hyun; Ryu, Jun Sun; Bae, Yun Soo; Kim, Hwan Mook

    2013-01-01

    Midazolam is a widely used anesthetic of the benzodiazepine class that has shown cytotoxicity and apoptosis-inducing activity in neuronal cells and lymphocytes. This study aims to evaluate the effect of midazolam on growth of K562 human leukemia cells and HT29 colon cancer cells. The in vivo effect of midazolam was investigated in BALB/c-nu mice bearing K562 and HT29 cells human tumor xenografts. The results show that midazolam decreased the viability of K562 and HT29 cells by inducing apoptosis and S phase cell-cycle arrest in a concentration-dependent manner. Midazolam activated caspase-9, capspase-3 and PARP indicating induction of the mitochondrial intrinsic pathway of apoptosis. Midazolam lowered mitochondrial membrane potential and increased apoptotic DNA fragmentation. Midazolam showed reactive oxygen species (ROS) scavenging activity through inhibition of NADPH oxidase 2 (Nox2) enzyme activity in K562 cells. Midazolam caused inhibition of pERK1/2 signaling which led to inhibition of the anti-apoptotic proteins Bcl-XL and XIAP and phosphorylation activation of the pro-apoptotic protein Bid. Midazolam inhibited growth of HT29 tumors in xenograft mice. Collectively our results demonstrate that midazolam caused growth inhibition of cancer cells via activation of the mitochondrial intrinsic pathway of apoptosis and inhibited HT29 tumor growth in xenograft mice. The mechanism underlying these effects of midazolam might be suppression of ROS production leading to modulation of apoptosis and growth regulatory proteins. These findings present possible clinical implications of midazolam as an anesthetic to relieve pain during in vivo anticancer drug delivery and to enhance anticancer efficacy through its ROS-scavenging and pro-apoptotic properties. PMID:24008365

  7. Prolyl oligopeptidase inhibition-induced growth arrest of human gastric cancer cells

    SciTech Connect

    Suzuki, Kanayo; Sakaguchi, Minoru; Tanaka, Satoshi; Yoshimoto, Tadashi; Takaoka, Masanori

    2014-01-03

    Highlights: •We examined the effects of prolyl oligopeptidase (POP) inhibition on p53 null gastric cancer cell growth. •POP inhibition-induced cell growth suppression was associated with an increase in a quiescent G{sub 0} state. •POP might regulate the exit from and/or reentry into the cell cycle. -- Abstract: Prolyl oligopeptidase (POP) is a serine endopeptidase that hydrolyzes post-proline peptide bonds in peptides that are <30 amino acids in length. We recently reported that POP inhibition suppressed the growth of human neuroblastoma cells. The growth suppression was associated with pronounced G{sub 0}/G{sub 1} cell cycle arrest and increased levels of the CDK inhibitor p27{sup kip1} and the tumor suppressor p53. In this study, we investigated the mechanism of POP inhibition-induced cell growth arrest using a human gastric cancer cell line, KATO III cells, which had a p53 gene deletion. POP specific inhibitors, 3-((4-[2-(E)-styrylphenoxy]butanoyl)-L-4-hydroxyprolyl)-thiazolidine (SUAM-14746) and benzyloxycarbonyl-thioprolyl-thioprolinal, or RNAi-mediated POP knockdown inhibited the growth of KATO III cells irrespective of their p53 status. SUAM-14746-induced growth inhibition was associated with G{sub 0}/G{sub 1} cell cycle phase arrest and increased levels of p27{sup kip1} in the nuclei and the pRb2/p130 protein expression. Moreover, SUAM-14746-mediated cell cycle arrest of KATO III cells was associated with an increase in the quiescent G{sub 0} state, defined by low level staining for the proliferation marker, Ki-67. These results indicate that POP may be a positive regulator of cell cycle progression by regulating the exit from and/or reentry into the cell cycle by KATO III cells.

  8. CTRP6 inhibits fibrogenesis in TGF-β1-stimulated human dermal fibroblasts

    SciTech Connect

    Fan, Rong-hui; Zhu, Xiu-mei; Sun, Yao-wen; Peng, Hui-zi; Wu, Hang-li; Gao, Wen-jie

    2016-07-08

    Skin fibrosis is characterized by excessive proliferation of fibroblasts and overproduction of extracellular matrix (ECM). C1q/tumor necrosis factor-related protein 6 (CTRP6), a member of CTRPs, has been involved in the development of cardiac fibrosis. However, the function and detailed regulatory mechanism of CTRP6 in skin fibrosis remain unclear. The aim of this study was to investigate the effect of CTRP6 on the activation of human dermal fibroblasts. Our results showed that CTRP6 was lowly expressed in scar tissues and transforming growth factor-β1 (TGF-β1)-treated dermal fibroblasts. CTRP6 overexpression significantly inhibited the proliferation of dermal fibroblasts, as well as suppressed the expression of ECM in TGF-β1-treated dermal fibroblasts. Furthermore, CTRP6 overexpression markedly inhibited TGF-β1-induced phosphorylation of Smad3 in dermal fibroblasts. In conclusion, the data reported here demonstrate that CTRP6 is able to inhibit the proliferation and ECM expression in human dermal fibroblasts through suppressing the TGF-β1/Smad3 signaling pathway. These findings suggest that CTRP6 may be a potential therapeutic target for the prevention of skin fibrosis. -- Highlights: •CTRP6 expression was decreased in scar tissues and TGF-β1-treated dermal fibroblasts. •CTRP6 inhibits TGF-β1-induced the proliferation of dermal fibroblasts. •CTRP6 inhibits expression of collagen type I and α-SMA. •CTRP6 inhibits the activation of TGF-β1/Smad3 signaling pathway in dermal fibroblasts.

  9. Synergistic growth inhibition by acyclic retinoid and vitamin K2 in human hepatocellular carcinoma cells.

    PubMed

    Kanamori, Toh; Shimizu, Masahito; Okuno, Masataka; Matsushima-Nishiwaki, Rie; Tsurumi, Hisashi; Kojima, Soichi; Moriwaki, Hisataka

    2007-03-01

    Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide. However, effective chemopreventive and chemotherapeutic agents for this cancer have not yet been developed. In clinical trials acyclic retinoid (ACR) and vitamin K(2) (VK(2)) decreased the recurrence rate of HCC. In the present study we examined the possible combined effects of ACR or another retinoid 9-cis retinoic acid (9cRA) plus VK(2) in the HuH7 human HCC cell line. We found that the combination of 1.0 microM ACR or 1.0 microM 9cRA plus 10 microM VK(2) synergistically inhibited the growth of HuH7 cells without affecting the growth of Hc normal human hepatocytes. The combined treatment with ACR plus VK(2) also acted synergistically to induce apoptosis in HuH7 cells. Treatment with VK(2) alone inhibited phosphorylation of the retinoid X receptor (RXR)alpha protein, which is regarded as a critical factor for liver carcinogenesis, through inhibition of Ras activation and extracellular signal-regulated kinase phosphorylation. Moreover, the inhibition of RXRalpha phosphorylation by VK(2) was enhanced when the cells were cotreated with ACR. The combination of retinoids plus VK(2) markedly increased both the retinoic acid receptor responsive element and retinoid X receptor responsive element promoter activities in HuH7 cells. Our results suggest that retinoids (especially ACR) and VK(2) cooperatively inhibit activation of the Ras/MAPK signaling pathway, subsequently inhibiting the phosphorylation of RXRalpha and the growth of HCC cells. This combination might therefore be effective for the chemoprevention and chemotherapy of HCC.

  10. Induction and inhibition of NAD(P)H: quinone reductase in murine and human skin.

    PubMed

    Merk, H; Jugert, F; Bonnekoh, B; Mahrle, G

    1991-01-01

    The purpose of this study was to characterize the human cutaneous NAD(P)H: quinone reductase (NQR) activity by known inhibitors of different reductases and to compare it with the murine skin and liver NQR activity. This enzyme plays a major role in the defence of cells against oxygen stress because it inhibits the 1-electron reduction of quinones to semiquinones and their subsequent oxidation to quinones termed as quinone redox cycle. It belongs to the aromatic hydrocarbon-responsive (Ah) battery. This gene battery includes Cyp1a1 (cytochrome P-450 IA1), Cyp1a2 (cytochrome P-450 IA2) and Nmo-1 [NAD(P)H: quinone reductase]. In the skin cytochrome P-450 IA1-dependent activity is about 1-5% compared to the corresponding activity in the liver, whereas NQR has the same activity in skin and liver. NQR was determined in the cytoplasm of murine skin, liver, and human keratinocytes using 2,6-dichlorophenolindophenol as the substrate. The Ah-receptor binding compounds, such as coal tar constituents, or 3-methylcholanthrene induce cytochrome P-450-dependent activities such as aryl hydrocarbon hydroxylase or 7-ethoxyresorufin-O-de-ethylase and NQR, whereas butyl hydroxytoluol, which does not bind to the Ah receptor, induces only NQR. For inhibition studies several known inhibitors of dihydrodiol dehydrogenase, aldo-keto and carbonyl reductase activities were used. There was a similar pattern of inhibition of the basal and induced activity in all tissues investigated. Pyrazole, progesterone and phenobarbital did not inhibit, whereas dicoumarol, rutin and indomethacin inhibited NQR activity in murine skin and liver as well as in human keratinocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Inhibition of isolated human myometrium contractility by minoxidil and reversal by glibenclamide.

    PubMed

    Prabhakaran, S S; Dhanasekar, K R; Thomas, E; Jose, R; Peedicayil, J; Samuel, P

    2010-03-01

    This study investigated the ability of the antihypertensive drug minoxidil to inhibit potassium chloride (KCl)-induced contractility of the isolated human myometrium. Twelve strips of myometrium obtained from 12 patients who underwent hysterectomy were triggered to contract with 55 mM KCl before and after incubation with 3 concentrations (1, 3 and 10 microM) of minoxidil. The percent inhibition by minoxidil on the extent of contraction, and the area under the contractile curve of KCl-induced contraction of the myometrial strips was determined. Furthermore, the effect of 10 microM glibenclamide on the inhibition generated by 3 microM minoxidil on KCl-induced contractility was studied. It was found that minoxidil produced a concentration-dependent inhibition of KCl-induced contractility of the myometrium and that glibenclamide reversed this inhibitory effect. These results suggest that the inhibitory effect of minoxidil on isolated human myometrium contractility may prove useful in clinical conditions requiring relaxation of the myometrium. 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

  12. Structural evidence that human acetylcholinesterase inhibited by tabun ages through O-dealkylation.

    PubMed

    Carletti, Eugénie; Colletier, Jacques-Philippe; Dupeux, Florine; Trovaslet, Marie; Masson, Patrick; Nachon, Florian

    2010-05-27

    Tabun is a warfare agent that inhibits human acetylcholinesterase (hAChE) by rapid phosphylation of the catalytic serine. A time-dependent reaction occurs on the tabun adduct, leading to an "aged" enzyme, resistant to oxime reactivators. The aging reaction may proceed via either dealkylation or deamidation, depending on the stereochemistry of the phosphoramidyl adduct. We solved the X-ray structure of aged tabun-hAChE complexed with fasciculin II, and we show that aging proceeds through O-dealkylation, in agreement with the aging mechanism that we determined for tabun-inhibited human butyrylcholinesterase and mouse acetylcholinesterase. Noteworthy, aging and binding of fasciculin II lead to an improved thermostability, resulting from additional stabilizing interactions between the two subdomains that face each other across the active site gorge. This first structure of hAChE inhibited by a nerve agent provides structural insight into the inhibition and aging mechanisms and a structural template for the design of molecules capable of reactivating aged hAChE.

  13. Inhibition of human GLUT1 and GLUT5 by plant carbohydrate products; insights into transport specificity

    PubMed Central

    George Thompson, Alayna M.; Iancu, Cristina V.; Nguyen, Thi Thanh Hanh; Kim, Doman; Choe, Jun-yong

    2015-01-01

    Glucose transporters GLUT1 (transports glucose) and GLUT5 (transports fructose), in addition to their functions in normal metabolism, have been implicated in several diseases including cancer and diabetes. While GLUT1 has several inhibitors, none have been described for GLUT5. By transport activity assays we found two plant products, rubusoside (from Rubus suavissimus) and astragalin-6-glucoside (a glycosylated derivative of astragalin, from Phytolacca americana) that inhibited human GLUT5. These plants are utilized in traditional medicine: R. suavissimus for weight loss and P. americana for cancer treatment, but the molecular interactions of these products are unknown. Rubusoside also inhibited human GLUT1, but astragalin-6-glucoside did not. In silico analysis of rubusoside:protein interactions pinpointed a major difference in substrate cavity between these transporters, a residue that is a tryptophan in GLUT1 but an alanine in GLUT5. Investigation of mutant proteins supported the importance of this position in ligand specificity. GLUT1W388A became susceptible to inhibition by astragalin-6-glucoside and resistant to rubusoside. GLUT5A396W transported fructose and also glucose, and maintained inhibition by rubusoside and astragalin-6-glucoside. Astragalin-6-glucoside can serve as a starting point in the design of specific inhibitors for GLUT5. The application of these studies to understanding glucose transporters and their interaction with substrates and ligands is discussed. PMID:26306809

  14. TEAD1 inhibits prolactin gene expression in cultured human uterine decidual cells.

    PubMed

    Kessler, Cherie A; Bachurski, Cindy J; Schroeder, Jennifer; Stanek, Jerzy; Handwerger, Stuart

    2008-11-25

    Forced overexpression of TEAD1 in human uterine fibroblast (HUF) and human endometrial stromal cells markedly inhibited prolactin promoter activity in both cell types in a dose-dependent manner, with maximal inhibition of greater than 90%. Conversely, the knockdown of TEAD1 expression in HUF cells with a TEAD1 siRNA resulted in a 75-80% increase in prolactin mRNA levels (p<0.01) compared to control cells exposed to a scrambled nonsense RNA. Mutagenesis of the putative TEAD site inhibited basal promoter activity by about 80%. However, mutagenesis of the TEAD site did not prevent TEAD1-induced inhibition of promoter activity; and the transcription activity of a minimal promoter fragment lacking a putative TEAD binding site was repressed by overexpression of TEAD1. Taken together, these findings suggest that the TEAD binding site on the prolactin promoter is important for the maintenance of basal prolactin promoter activity and that overexpression of TEAD1 has a dominant-negative effect on prolactin promoter activity, probably by interacting directly with other transcription factors.

  15. TEAD1 inhibits prolactin gene expression in cultured human uterine decidual cells1

    PubMed Central

    Kessler, Cherie A.; Bachurski, Cindy J.; Schroeder, Jennifer; Stanek, Jerzy; Handwerger, Stuart

    2008-01-01

    Forced overexpression of TEAD1 in human uterine fibroblast (HUF) and human endometrial stromal cells markedly inhibited prolactin promoter activity in both cell types in a dose-dependent manner, with maximal inhibition of greater than 90%. Conversely, the knockdown of TEAD1 expression in HUF cells with a TEAD1 siRNA resulted in a 75–80% increase in prolactin mRNA levels (P<0.01) compared to control cells exposed to a scrambled nonsense RNA. Mutagenesis of the putative TEAD site inhibited basal promoter activity by about 80%. However, mutagenesis of the TEAD site did not prevent TEAD1-induced inhibition of promoter activity; and the transcription activity of a minimal promoter fragment lacking a putative TEAD binding site was repressed by overexpression of TEAD1. Taken together, these findings suggest that the TEAD binding site on the prolactin promoter is important for the maintenance of basal prolactin promoter activity and that overexpression of TEAD1 has a dominant-negative effect on prolactin promoter activity, probably by interacting directly with other transcription factors. PMID:18775765

  16. Free fatty acid receptor (FFAR) agonists inhibit proliferation of human ovarian cancer cells.

    PubMed

    Hopkins, Mandi M; Meier, Kathryn E

    2017-07-01

    Many cellular actions of omega-3 fatty acids are mediated by two G protein-coupled receptors, FFA1 and FFA4, free fatty acid receptor (FFAR) family members that are activated by these dietary constituents. FFAR agonists inhibit proliferation of human prostate and breast cancer cells. Since omega-3 fatty acids can inhibit ovarian cancer cell growth, the current study tested the potential role of FFARs in the response. OVCAR3 and SKOV3 human ovarian cancer cell lines express mRNA for FFA1; FFA4 mRNA was detected at low levels in SKOV3 but not OVCAR3. Lysophosphatidic acid (LPA) and epidermal growth factor (EGF) stimulated proliferation of both cell lines; these responses were inhibited by eicosopentaneoic acid (EPA) and by GW9508, a synthetic FFAR agonist. The LPA antagonist Ki16425 also inhibited LPA- and EGF-induced proliferation; FFAR agonists had no further effect when added with Ki16425. The results suggest that FFARs are potential targets for ovarian cancer therapy. Copyright © 2017. Published by Elsevier Ltd.

  17. 3-Bromopyruvate inhibits cell proliferation and induces apoptosis in CD133+ population in human glioma.

    PubMed

    Xu, Dong-Qiang; Tan, Xiao-Yu; Zhang, Bao-Wei; Wu, Tao; Liu, Ping; Sun, Shao-Jun; Cao, Yin-Guang

    2016-03-01

    The study was aimed to investigate the role of 3-bromopyruvate in inhibition of CD133+ U87 human glioma cell population growth. The results demonstrated that 3-bromopyruvate inhibited the viability of both CD133+ and parental cells derived from U87 human glioma cell line. However, the 3-bromopyruvate-induced inhibition in viability was more prominent in CD133+ cells at 10 μM concentration after 48 h. Treatment of CD133+ cells with 3-bromopyruvate caused reduction in cell population and cell size, membrane bubbling, and degradation of cell membranes. Hoechst 33258 staining showed condensation of chromatin material and fragmentation of DNA in treated CD133+ cells after 48 h. 3-Bromopyruvate inhibited the migration rate of CD133+ cells significantly compared to the parental cells. Flow cytometry revealed that exposure of CD133+ cells to 3-bromopyruvate increased the cell population in S phase from 24.5 to 37.9 % with increase in time from 12 to 48 h. In addition, 3-bromopyruvate significantly enhanced the expression of Bax and cleaved caspase 3 in CD133+ cells compared to the parental cells. Therefore, 3-bromopyruvate is a potent chemotherapeutic agent for the treatment of glioma by targeting stem cells selectively.

  18. Fear potentiation and fear inhibition in a human fear-potentiated startle paradigm.

    PubMed

    Jovanovic, Tanja; Keyes, Megan; Fiallos, Ana; Myers, Karyn M; Davis, Michael; Duncan, Erica J

    2005-06-15

    The inability to suppress excessive fear or anxiety is a significant clinical problem. In the laboratory, extinction is a preferred method for the study of fear inhibition; however, in this paradigm the same stimulus causes both elicitation (excitation) and inhibition of fear, making it difficult to know whether an experimental manipulation that affects extinction does so by affecting one or both of these processes. For this reason, we sought to develop a behavioral procedure in humans that would render a stimulus primarily inhibitory. We adapted a conditional discrimination procedure (AX+/BX-), previously validated in animals, to a human fear-potentiated startle paradigm. Forty-one healthy volunteers were presented with one set of colored lights paired with the delivery of aversive airblasts to the throat (AX+) and a different series of lights presented without airblasts (BX-). Participants exhibited fear potentiation to AX+, discrimination between AX+ and BX-, and transfer of fear inhibition to A in an AB compound test but not in an AC compound test. We believe this procedure will advance clinical research on fear disorders, such as posttraumatic stress disorder and phobias, by providing an effective and relatively independent measure of fear potentiation and fear inhibition.

  19. Feto-maternal interface of human placenta inhibits angiogenesis in the chick chorioallantoic membrane (CAM) assay.

    PubMed

    Stallmach, T; Duc, C; van Praag, E; Mumenthaler, C; Ott, C; Kolb, S A; Hebisch, G; Steiner, R

    2001-01-01

    The rapidly growing chorionic villi of the human placenta characteristically show constant blood vessel growth and differentiation. In contrast, the underlying decidua reveals tissue remodeling without apparent angiogenesis. Using the chick chorioallantoic membrane (CAM) assay, we found marked inhibition of angiogenesis by the feto-maternal interface tissue derived from nine human placentas obtained minutes after delivery. Inhibition was prevented by the addition of monensin, which blocks the release of synthesized cell products, and was markedly reduced by drying or freezing the tissue before the assay. Histology, combined with statistical analysis of the constituent cell types, correlated inhibition of angiogenesis with the number of fetally-derived extravillous trophoblasts in the feto-maternal interface tissue. Electron microscopy revealed endothelial cell damage in preexisting small (but not large) CAM vessels. We conclude that decidual tissue inhibited angiogenesis by releasing a water soluble factor which was under apparent constant production by vaible trophoblast on the CAM. The extravillous trophoblast population resembles tumor cells in its migratory and invasive properties but, in contrast to tumor induced angiogenesis, it is angiostatic, perhaps to counteract angiogenic proteins leaking from the intervillous space which could be detrimental to the maternal organism if active.

  20. TNP-470 and recombinant human interferon-alpha2a inhibit angiogenesis synergistically.

    PubMed

    Minischetti, M; Vacca, A; Ribatti, D; Iurlaro, M; Ria, R; Pellegrino, A; Gasparini, G; Dammacco, A F

    2000-06-01

    The hypothesis that the combination of two known antiangiogenic agents TNP-470 and interferon (IFN)-alpha exerts synergistic effects has been investigated in vitro and in vivo. In vitro, TNP-470 and recombinant human IFN-alpha2a (rhIFN-alpha2a) resulted in a dose-dependent inhibition of proliferation of human umbilical vein endothelial cells (HUVECs) and EA.hy926 endothelial cells. Compared with the two agents used singly at their lowest or ineffective doses, combined treatment with the same doses inhibited more intensely in the absence of cytotoxicity and displayed similar behaviour on cell chemotaxis and capillary morphogenesis on Matrigel. However, the secretion of matrix metalloproteinase 2 (MMP-2) and MMP-9 was not influenced by the two agents, either alone or in combination, even when they were applied at their lowest efficacious doses or at higher cytotoxic doses. Experiments in vivo with the chick embryo chorioallantoic membrane (CAM)-sponge assay revealed the same dose-dependent inhibition and synergy. As the basic fibroblast growth factor (bFGF)-induced angiogenesis in the CAM-sponge model was strongly inhibited by the combined treatment, TNP-470 and rhIFN-alpha2a would appear to exert antiangiogenesis synergistically, perhaps by interfering with the bFGF-mediated pathway.

  1. Caudatin Inhibits Human Glioma Cells Growth Through Triggering DNA Damage-Mediated Cell Cycle Arrest.

    PubMed

    Fu, Xiao-yan; Zhang, Shuai; Wang, Kun; Yang, Ming-feng; Fan, Cun-dong; Sun, Bao-liang

    2015-10-01

    Caudatin, one of the species of C-21 steroidal glycosides mainly isolated from the root of Cynanchum bungei Decne, exhibits potent anticancer activities. However, the mechanism remains poorly defined. In the present study, the growth inhibitory effect and mechanism of caudatin on human glioma cells were evaluated in vitro. The results revealed that caudatin time- and dose-dependently inhibited U251 and U87 cells growth. Flow cytometry analysis indicated that caudatin-induced growth inhibition against U251 and U87 cells was mainly achieved by the induction of G0/G1 and S-phase cell cycle arrest through triggering DNA damage, as convinced by the up-regulation of p53, p21, and histone phosphorylation, as well as the down-regulation of cyclin D1. Moreover, caudatin treatment also triggered the activation of ERK and inactivation of AKT pathway. LY294002 (an AKT inhibitor) addition enhanced caudation-induced AKT inhibition, indicating that caudatin inhibited U251 cells growth in an AKT-dependent manner. Taken together, these results indicate that caudatin may act as a novel cytostatic reagent against human glioma cells through the induction of DNA damage-mediated cell cycle arrest with the involvement of modulating MAPK and AKT pathways.

  2. ERP44 inhibits human lung cancer cell migration mainly via IP3R2.

    PubMed

    Huang, Xue; Jin, Meng; Chen, Ying-Xiao; Wang, Jun; Zhai, Kui; Chang, Yan; Yuan, Qi; Yao, Kai-Tai; Ji, Guangju

    2016-06-01

    Cancer cell migration is involved in tumour metastasis. However, the relationship between calcium signalling and cancer migration is not well elucidated. In this study, we used the human lung adenocarcinoma A549 cell line to examine the role of endoplasmic reticulum protein 44 (ERP44), which has been reported to regulate calcium release inside of the endoplasmic reticulum (ER), in cell migration. We found that the inositol 1,4,5-trisphosphate receptors (IP3Rs/ITPRs) inhibitor 2-APB significantly inhibited A549 cell migration by inhibiting cell polarization and pseudopodium protrusion, which suggests that Ca2+ is necessary for A549 cell migration. Similarly, the overexpression of ERP44 reduced intracellular Ca2+ release via IP3Rs, altered cell morphology and significantly inhibited the migration of A549 cells. These phenomena were primarily dependent on IP3R2 because wound healing in A549 cells with IP3R2 rather than IP3R1 or IP3R3 siRNA was markedly inhibited. Moreover, the overexpression of ERP44 did not affect the migration of the human neuroblastoma cell line SH-SY5Y, which mainly expresses IP3R1. Based on the above observations, we conclude that ERP44 regulates A549 cell migration mainly via an IP3R2-dependent pathway.

  3. ERP44 inhibits human lung cancer cell migration mainly via IP3R2

    PubMed Central

    Zhai, Kui; Chang, Yan; Yuan, Qi; Yao, Kai-Tai; Ji, Guangju

    2016-01-01

    Cancer cell migration is involved in tumour metastasis. However, the relationship between calcium signalling and cancer migration is not well elucidated. In this study, we used the human lung adenocarcinoma A549 cell line to examine the role of endoplasmic reticulum protein 44 (ERP44), which has been reported to regulate calcium release inside of the endoplasmic reticulum (ER), in cell migration. We found that the inositol 1,4,5-trisphosphate receptors (IP3Rs/ITPRs) inhibitor 2-APB significantly inhibited A549 cell migration by inhibiting cell polarization and pseudopodium protrusion, which suggests that Ca2+ is necessary for A549 cell migration. Similarly, the overexpression of ERP44 reduced intracellular Ca2+ release via IP3Rs, altered cell morphology and significantly inhibited the migration of A549 cells. These phenomena were primarily dependent on IP3R2 because wound healing in A549 cells with IP3R2 rather than IP3R1 or IP3R3 siRNA was markedly inhibited. Moreover, the overexpression of ERP44 did not affect the migration of the human neuroblastoma cell line SH-SY5Y, which mainly expresses IP3R1. Based on the above observations, we conclude that ERP44 regulates A549 cell migration mainly via an IP3R2-dependent pathway. PMID:27347718

  4. Tamoxifen does not inhibit the swell activated chloride channel in human neutrophils during the respiratory burst

    SciTech Connect

    Ahluwalia, Jatinder

    2008-10-31

    Effective functioning of neutrophils relies upon electron translocation through the NADPH oxidase (NOX). The electron current generated (I{sub e}) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential in activated human neutrophils. Swelling activated chloride channels have been demonstrated in part to counteract the depolarisation generated by the NADPH oxidase I{sub e}. In the present study, the effects of inhibitors of swell activated chloride channels on ROS production and on the swelling activated chloride conductance was investigated in activated human neutrophils. Tamoxifen (10 {mu}M), a specific inhibitor for swell activated chloride channels in neutrophils, completely inhibited both the PMA and FMLP stimulated respiratory burst. This inhibition of the neutrophil respiratory burst was not due to the blocking effect of tamoxifen on the swelling activated chloride conductance in these cells. These results demonstrate that a tamoxifen insensitive swell activated chloride channel has important significance during the neutrophil respiratory burst.

  5. Antibodies against dengue virus E protein peptide bind to human plasminogen and inhibit plasmin activity

    PubMed Central

    HUANG, Y H; CHANG, B I; LEI, H Y; LIU, H S; LIU†, C C; WU, H L; YEH, T M

    1997-01-01

    Both mice and rabbits immunized with dengue virus E protein peptide spanning amino acids 100–119 (D4E) produced antibodies that reacted not only with the D4E peptide itself but also with human plasminogen, as shown by ELISA and Western blot. Sera from dengue virus-hyperimmunized mice and dengue patients also contained antibodies against D4E and plasminogen. Furthermore, such sera all contained plasmin inhibitory activity. Using affinity-purified anti-D4E antibodies and free D4E peptide for competitive inhibition, we demonstrated that the inhibition of plasmin activity was due to anti-D4E antibodies rather than other substances in the sera. Taken together, these results suggest dengue virus E protein amino acids 100–119 are a cross-reactive immunogenic region, and antibodies against this region may interfere with human fibrinolysis. PMID:9353146

  6. Deoxynivalenol inhibits proliferation and induces apoptosis in human umbilical vein endothelial cells.

    PubMed

    Deng, Chao; Ji, Changyun; Qin, Weisen; Cao, Xifeng; Zhong, Jialian; Li, Yugu; Srinivas, Swaminath; Feng, Youjun; Deng, Xianbo

    2016-04-01

    Deoxynivalenol (DON) is a stable mycotoxins found in cereals infected by certain fungal species and causes adverse health effects in animals and human such as vomiting, diarrhea and reproductive toxicity. In this study, we investigated the toxic and apoptotic effects of DON in human umbilical vein endothelial cells (HUVECs), a good model for studying inflammation. The results show that DON significantly inhibited the viability of HUVECs. DON could also inhibit the proliferation of HUVECs through G2/M phase arrest in cell cycle progression. Moreover, oxidative stress induced by DON was indicated by observations of increased levels of reactive oxygen species (ROS). In addition, DON also causes mitochondrial damage by decreasing the mitochondrial membrane potential and inducing apoptosis by up-regulation of apoptosis-related genes like caspase-3, caspase-9, and Bax genes, and down-regulation of Bcl-2 gene. These results together suggest that DON could induce cell cycle arrest, oxidative stress, and apoptosis in HUVECs.

  7. In vitro growth inhibition of human cancer cells by novel honokiol analogs.

    PubMed

    Lin, Jyh Ming; Prakasha Gowda, A S; Sharma, Arun K; Amin, Shantu

    2012-05-15

    Honokiol possesses many pharmacological activities including anti-cancer properties. Here in, we designed and synthesized honokiol analogs that block major honokiol metabolic pathway which may enhance their effectiveness. We studied their cytotoxicity in human cancer cells and evaluated possible mechanism of cell cycle arrest. Two analogs, namely 2 and 4, showed much higher growth inhibitory activity in A549 human lung cancer cells and significant increase of cell population in the G0-G1 phase. Further elucidation of the inhibition mechanism on cell cycle showed that analogs 2 and 4 inhibit both CDK1 and cyclin B1 protien levels in A549 cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Inhibition of ganciclovir-resistant human cytomegalovirus replication by Kampo (Japanese herbal medicine).

    PubMed

    Murayama, Tsugiya; Yamaguchi, Nobuo; Iwamoto, Kozo; Eizuru, Yoshito

    2006-01-01

    We examined the effect of Kampo on the replication of ganciclovir (GCV)-resistant human cytomegalovirus (HCMV) in the human embryonic fibroblast cell line MRC-5. Treatment of HCMV-infected cells with Sho-seiryu-to (SST; Xiao-Qing-Long-Tang in Chinese) resulted in the inhibition of viral replication without affecting the cell growth. SST treatment decreased the synthesis of viral DNA, but had no virucidal effect on cell-free HCMV. However, the inhibitory effect of SST on HCMV replication was ablated by anti-interferon-beta (IFN-beta) antibody suggesting that SST inhibits the replication of GCV-resistant HCMV through the induction of IFN-beta. These results suggest that SST is a novel compund with potential as an anti-HCMV.

  9. Theophylline prevents NAD{sup +} depletion via PARP-1 inhibition in human pulmonary epithelial cells

    SciTech Connect

    Moonen, Harald J.J. . E-mail: h.moonen@grat.unimaas.nl; Geraets, Liesbeth; Vaarhorst, Anika; Bast, Aalt; Wouters, Emiel F.M.; Hageman, Geja J.

    2005-12-30

    Oxidative DNA damage, as occurs during exacerbations in chronic obstructive pulmonary disease (COPD), highly activates the nuclear enzyme poly(ADP-ribose)polymerase-1 (PARP-1). This can lead to cellular depletion of its substrate NAD{sup +}, resulting in an energy crisis and ultimately in cell death. Inhibition of PARP-1 results in preservation of the intracellular NAD{sup +} pool, and of NAD{sup +}-dependent cellular processes. In this study, PARP-1 activation by hydrogen peroxide decreased intracellular NAD{sup +} levels in human pulmonary epithelial cells, which was found to be prevented in a dose-dependent manner by theophylline, a widely used compound in the treatment of COPD. This enzyme inhibition by theophylline was confirmed in an ELISA using purified human PARP-1 and was found to be competitive by nature. These findings provide new mechanistic insights into the therapeutic effect of theophylline in oxidative stress-induced lung pathologies.

  10. Buthionine sulfoximine inhibition of cystine uptake and glutathione biosynthesis in human lung carcinoma cells

    SciTech Connect

    Brodie, A.E.; Reed, D.J.

    1985-03-15

    Intracellular glutathione (GSH) content of human lung carcinoma cells, A549, in log phase was 25 +/- 5 nmol/10(6) cells, which is considerably higher than that reported in other tumor cells. After partial depletion of GSH with diethyl maleate (DEM), addition of cystine to the medium allowed full resynthesis of GSH in 4 hr, cysteine in the same time period led to less resynthesis, and methionine provided minimal resynthesis. Using cystine as the sole sulfur source and with buthionine sulfoximine (BSO, 5 mM) included in the medium after cells were depleted with DEM, inhibition of both cystine uptake and resynthesis of GSH occurred. BSO inhibited (/sup 35/S)cystine uptake (as early as 10 min) in a concentration-dependent process, ranging from a 28% decrease for 1 microM BSO to an 85% decrease for 100 microM BSO compared to the control cells after 240 min of incubation. In addition, GSH resynthesis from (/sup 35/S)cystine for 240 min was inhibited in a parallel dose-dependent manner, in that 1 microM BSO caused a 27% decrease and 100 microM BSO provided a 75% decrease from control values. BSO did not inhibit the uptake of (/sup 35/S)methionine, but inhibited the low amount of resynthesis of GSH when methionine was the sole sulfur source. BSO did not inhibit the uptake of arginine, phenylalanine, and leucine. DL-, L-, and methyl ester-BSO each inhibited (/sup 35/S)cystine uptake and incorporation into GSH to a similar extent. The half-life of GSH was 3.5 +/- 0.4 hr in A549 cells that were grown in complete medium with GSH synthesis occurring.

  11. Secondhand smoke inhibits both Cl- and K+ conductances in normal human bronchial epithelial cells

    PubMed Central

    2009-01-01

    Secondhand smoke (SHS) exposure is an independent risk factor for asthma, rhinosinusitis, and more severe respiratory tract infections in children and adults. Impaired mucociliary clearance with subsequent mucus retention contributes to the pathophysiology of each of these diseases, suggesting that altered epithelial salt and water transport may play an etiological role. To test the hypothesis that SHS would alter epithelial ion transport, we designed a system for in vitro exposure of mature, well-differentiated human bronchial epithelial cells to SHS. We show that SHS exposure inhibits cAMP-stimulated, bumetanide-sensitive anion secretion by 25 to 40% in a time-dependent fashion in these cells. Increasing the amount of carbon monoxide to 100 ppm from 5 ppm did not increase the amount of inhibition, and filtering SHS reduced inhibition significantly. It was determined that SHS inhibited cAMP-dependent apical membrane chloride conductance by 25% and Ba2+-sensitive basolateral membrane potassium conductance by 50%. These data confirm previous findings that cigarette smoke inhibits chloride secretion in a novel model of smoke exposure designed to mimic SHS exposure. They also extend previous findings to demonstrate an effect on basolateral K+ conductance. Therefore, pharmacological agents that increase either apical membrane chloride conductance or basolateral membrane potassium conductance might be of therapeutic benefit in patients with diseases related to SHS exposure. PMID:19943936

  12. Inhibition of human breast and colorectal cancer cells by Viburnum foetens L. extracts in vitro

    PubMed Central

    Waheed, Abdul; Bibi, Yamin; Nisa, Sobia; Chaudhary, Fayyaz M; Sahreen, Sumaira; Zia, Muhammad

    2013-01-01

    Objective To investigate efficacy of Viburnum foetens (V. foetens) extracts against different cancer lines. Methods The crude extract and fractions of V. foetens are evaluated against MDA MB-468 and Caco-2 cancer cell lines by using MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl- 2H-tetrazolium bromide) assays. These extracts are also tested against breast carcinoma and human colon adenocarcinoma through NRU (neutral red uptake) assay. Results The crude extract inhibited the cancerous cell growth in a dose dependent manner. From the MTT assay it is obvious that the ethylacetate fraction significantly inhibited the growth of Caco-2 (93.44%) cell. Similarly, the methanol and ethylacetate fractions shows 99% and 96% inhibition of MCF-7 and Caco-2 cell lines by NRU assay. Furthermore, the ethylacetate fraction also exhibited momentous inhibition of MDA MB-468 cells in both assays. Other fractions i.e. chloroform, hexane also inhibited cancer cell proliferation at a significant level. Natural products exhibited significant activity against multiple cancerous cells. Conclusions In this framework, we can speculate that the present study will be helpful in the identification and isolation of novel anticancer drug compounds from the crude extract (i.e., methanol and ethyl acetate fractions) of V. foetens.

  13. Legume lectins inhibit human parainfluenza virus type 2 infection by interfering with the entry.

    PubMed

    Uematsu, Jun; Koyama, Aoi; Takano, Sayaka; Ura, Yukari; Tanemura, Miho; Kihira, Sahoko; Yamamoto, Hidetaka; Kawano, Mitsuo; Tsurudome, Masato; O'Brien, Myles; Komada, Hiroshi

    2012-07-01

    Three lectins with different sugar binding specificities were investigated for anti-viral activity against human parainfluenza virus type 2 (hPIV-2). The lectins, concanavalin A (Con A), lens culinaris agglutinin (LCA) and peanut agglutinin (PNA), inhibited cell fusion and hemadsorption induced by hPIV-2. Virus nucleoprotein (NP) gene synthesis was largely inhibited, but fusion (F) and hemagglutinin-neuraminidase (HN) gene syntheses were not. An indirect immunofluorescence study showed that Con A inhibited virus NP, F and HN protein syntheses, but LCA did not completely inhibit them, and that PNA inhibited only NP protein synthesis. Using a recombinant green fluorescence protein-expressing hPIV-2, without matrix protein (rghPIV-2ΔM), it was found that virus entry into the cells was not completely prevented. The lectins considerably reduced the number of viruses released compared with that of virus infected cells. The lectins bound to cell surface within 10 min, and many aggregates were observed at 30 min. Con A and LCA slightly disrupted actin microfilaments and microtubules, but PNA had almost no effect on them. These results indicated that the inhibitory effects of the lectins were caused mainly by the considerable prevention of virus adsorption to the cells by the lectin binding to their receptors.

  14. Secondhand smoke inhibits both Cl- and K+ conductances in normal human bronchial epithelial cells.

    PubMed

    Savitski, Amy N; Mesaros, Clementina; Blair, Ian A; Cohen, Noam A; Kreindler, James L

    2009-11-27

    Secondhand smoke (SHS) exposure is an independent risk factor for asthma, rhinosinusitis, and more severe respiratory tract infections in children and adults. Impaired mucociliary clearance with subsequent mucus retention contributes to the pathophysiology of each of these diseases, suggesting that altered epithelial salt and water transport may play an etiological role. To test the hypothesis that SHS would alter epithelial ion transport, we designed a system for in vitro exposure of mature, well-differentiated human bronchial epithelial cells to SHS. We show that SHS exposure inhibits cAMP-stimulated, bumetanide-sensitive anion secretion by 25 to 40% in a time-dependent fashion in these cells. Increasing the amount of carbon monoxide to 100 ppm from 5 ppm did not increase the amount of inhibition, and filtering SHS reduced inhibition significantly. It was determined that SHS inhibited cAMP-dependent apical membrane chloride conductance by 25% and Ba2+-sensitive basolateral membrane potassium conductance by 50%. These data confirm previous findings that cigarette smoke inhibits chloride secretion in a novel model of smoke exposure designed to mimic SHS exposure. They also extend previous findings to demonstrate an effect on basolateral K+ conductance. Therefore, pharmacological agents that increase either apical membrane chloride conductance or basolateral membrane potassium conductance might be of therapeutic benefit in patients with diseases related to SHS exposure.

  15. Heparin fragments inhibit human vascular smooth muscle cell proliferation in vitro

    SciTech Connect

    Selden, S.C.; Johnson, W.V.; Maciag, T.

    1986-03-01

    The authors have examined the effect of heparin on human abdominal aortic smooth muscle cell growth. Cell proliferation was inhibited by more than 90% at a concentration of 20 ..mu..g/ml in a 12 day growth assay using heparin from Sigma, Upjohn or Calbiochem. Additionally, 200 ..mu..g/ml Upjohn heparin inhibits /sup 3/H-thymidine incorporation by 50% in short term assays using serum or purified platelet-derived growth factor (25-100ng/ml) to initiate the cell cycle. Homogeneous size classes of heparin fragments were prepared by nitrous acid cleavage and BioGel P-10 filtration chromatography. Deca-, octa-, hexa-, tetra-, and di-saccharides inhibited proliferation by 90% at concentrations of 280, 320, 260, 180 and 100 ..mu..g/ml, respectively, in a 12 day growth assay. These data confirm the work of Castellot et.al. and extend the range of inhibitory fragments down to the tetra- and di-saccharide size. These data suggest, therefore, that di-saccharide subunit of heparin is sufficient to inhibit vascular smooth muscle cell proliferation. The authors are now examining the role of the anhydromannose moiety on the reducing end of the nitrous acid generated fragments as a possible mediator of heparin-induced inhibition of vascular smooth muscle cell proliferation.

  16. Paired Associative Stimulation Induces Change in Presynaptic Inhibition of Ia Terminals in Wrist Flexors in Humans

    PubMed Central

    Russmann, Heike; Shamim, Ejaz A.; Meunier, Sabine; Hallett, Mark

    2010-01-01

    Enhancements in the strength of corticospinal projections to muscles are induced in conscious humans by paired associative stimulation (PAS) to the motor cortex. Although most of the previous studies support the hypothesis that the increase of the amplitude of motor evoked potentials (MEPs) by PAS involves long-term potentiation (LTP)-like mechanism in cortical synapses, changes in spinal excitability after PAS have been reported, suggestive of parallel modifications in both cortical and spinal excitability. In a first series of experiments (experiment 1), we confirmed that both flexor carpi radialis (FCR) MEPs and FCR H reflex recruitment curves are enhanced by PAS. To elucidate the mechanism responsible for this change in the H reflex amplitude, we tested, using the same subjects, the hypothesis that enhanced H reflexes are caused by a down-regulation of the efficacy of mechanisms controlling Ia afferent discharge, including presynaptic Ia inhibition and postactivation depression. To address this question, amounts of both presynaptic Ia inhibition of FCR Ia terminals (D1and D2 inhibitions methods; experiment 2) and postactivation depression (experiment 3) were determined before and after PAS. Results showed that PAS induces a significant decrease of presynaptic Ia inhibition of FCR terminals, which was concomitant with the facilitation of the H reflex. Postactivation depression was unaffected by PAS. It is argued that enhancement of segmental excitation by PAS relies on a selective effect of PAS on the interneurons controlling presynaptic inhibition of Ia terminals. PMID:20538768

  17. Fucoidan extract derived from Undaria pinnatifida inhibits angiogenesis by human umbilical vein endothelial cells.

    PubMed

    Liu, Fang; Wang, Jia; Chang, Alan K; Liu, Bing; Yang, Lili; Li, Qiaomei; Wang, Peisheng; Zou, Xiangyang

    2012-06-15

    In recent years, anti-angiogenic therapy has become an effective strategy for inhibiting tumor growth. Fucoidan is a class of fucose-enriched sulfated polysaccharides found in brown algae, and it is known to have strong anti-tumor property. Using a human umbilical vein endothelial cells (HUVEC)-based cell culture model, the present study investigated the anti-angiogenic activity of fucoidan extracted from the brown seaweed Undaria pinnatifida. Treatment of HUVECs with various concentrations of fucoidan resulted in significant inhibition of cell proliferation, cell migration, tube formation and vascular network formation. However, significant inhibition of cell proliferation only occurred with longer treatment time (48 h instead of 24h or less). About 40% of cell proliferation and cell migration and 61% of tube formation by HUVECs were inhibited by 400 μg/ml fucoidan, the maximum concentration tested. These results appeared to suggest that modulation of angiogenesis by fucoidan might not occur through growth inhibition and apoptosis. Ex vivo angiogenesis assay demonstrated that at 100 μg/ml, fucoidan caused significant reduction in microvessel outgrowth. Western blot and RT-PCR analyses indicated that at 400 μg/ml, fucoidan significantly reduced the expression of the angiogenesis factor VEGF-A in the suppression of angiogenesis activity. Our results showed that fucoidan isolated from U. pinnatifida may have a new therapeutic potential in the prevention angiogenesis-related diseases.

  18. Soluble human complement receptor type 1 inhibits complement-mediated host defense.

    PubMed

    Swift, A J; Collins, T S; Bugelski, P; Winkelstein, J A

    1994-09-01

    Soluble complement receptor type 1 (sCR1) is a powerful inhibitor of complement activation. Because of this ability, sCR1 may prove to be an important therapeutic agent that can be used to block the immunopathologic effects of uncontrolled complement activation in a variety of clinically significant disorders. Although several previous studies have examined the ability of sCR1 to inhibit complemented-mediated immunopathologic damage, there is no information on its ability to interfere with the host's defense against infection. In the current experiments sCR1 exerted a concentration-dependent inhibitory effect on the phagocytosis of Streptococcus pneumoniae by human polymorphonuclear leukocytes in vitro. Not only di sCR1 inhibit complement-dependent opsonization of the pneumococcus but at higher concentrations it also inhibited the ingestion of bacteria which had been previously opsonized. Furthermore, when rats were injected with sCR1, it inhibited both their serum hemolytic activity and serum opsonic activity in a dose-dependent fashion. Finally, for rats treated with sCR1, the 50% lethal dose was S. pneumoniae and Pseudomonas aeruginosa. These data demonstrate that sCR1 significantly inhibits complement-mediated host against bacterial infection.

  19. Legume Lectins Inhibit Human Parainfluenza Virus Type 2 Infection by Interfering with the Entr

    PubMed Central

    Uematsu, Jun; Koyama, Aoi; Takano, Sayaka; Ura, Yukari; Tanemura, Miho; Kihira, Sahoko; Yamamoto, Hidetaka; Kawano, Mitsuo; Tsurudome, Masato; O’Brien, Myles; Komada, Hiroshi

    2012-01-01

    Three lectins with different sugar binding specificities were investigated for anti-viral activity against human parainfluenza virus type 2 (hPIV-2). The lectins, concanavalin A (Con A), lens culinaris agglutinin (LCA) and peanut agglutinin (PNA), inhibited cell fusion and hemadsorption induced by hPIV-2. Virus nucleoprotein (NP) gene synthesis was largely inhibited, but fusion (F) and hemagglutinin-neuraminidase (HN) gene syntheses were not. An indirect immunofluorescence study showed that Con A inhibited virus NP, F and HN protein syntheses, but LCA did not completely inhibit them, and that PNA inhibited only NP protein synthesis. Using a recombinant green fluorescence protein-expressing hPIV-2, without matrix protein (rghPIV-2ΔM), it was found that virus entry into the cells was not completely prevented. The lectins considerably reduced the number of viruses released compared with that of virus infected cells. The lectins bound to cell surface within 10 min, and many aggregates were observed at 30 min. Con A and LCA slightly disrupted actin microfilaments and microtubules, but PNA had almost no effect on them. These results indicated that the inhibitory effects of the lectins were caused mainly by the considerable prevention of virus adsorption to the cells by the lectin binding to their receptors. PMID:22852043

  20. RNase P Ribozymes Inhibit the Replication of Human Cytomegalovirus by Targeting Essential Viral Capsid Proteins.

    PubMed

    Yang, Zhu; Reeves, Michael; Ye, Jun; Trang, Phong; Zhu, Li; Sheng, Jingxue; Wang, Yu; Zen, Ke; Wu, Jianguo; Liu, Fenyong

    2015-06-24

    An engineered RNase P-based ribozyme variant, which was generated using the in vitro selection procedure, was used to target the overlapping mRNA region of two proteins essential for human cytomegalovirus (HCMV) replication: capsid assembly protein (AP) and protease (PR). In vitro studies showed that the generated variant, V718-A, cleaved the target AP mRNA sequence efficiently and its activity was about 60-fold higher than that of wild type ribozyme M1-A. Furthermore, we observed a reduction of 98%-99% in AP/PR expression and an inhibition of 50,000 fold in viral growth in cells with V718-A, while a 75% reduction in AP/PR expression and a 500-fold inhibition in viral growth was found in cells with M1-A. Examination of the antiviral effects of the generated ribozyme on the HCMV replication cycle suggested that viral DNA encapsidation was inhibited and as a consequence, viral capsid assembly was blocked when the expression of AP and PR was inhibited by the ribozyme. Thus, our study indicates that the generated ribozyme variant is highly effective in inhibiting HCMV gene expression and blocking viral replication, and suggests that engineered RNase P ribozyme can be potentially developed as a promising gene-targeting agent for anti-HCMV therapy.

  1. Apple peel bioactive rich extracts effectively inhibit in vitro human LDL cholesterol oxidation.

    PubMed

    Thilakarathna, Surangi H; Rupasinghe, H P Vasantha; Needs, Paul W

    2013-05-01

    Apple peels are rich in antioxidant bioactives and hence can possess the ability to inhibit human low density lipoprotein cholesterol (LDL-C) oxidation. LDL-C oxidation is known to initiate atherosclerotic plaque formation. Unique quercetin-rich (QAE) and triterpene-rich (TAE) apple peel extracts, their constituent compounds and three in vivo quercetin metabolites were investigated for in vitro LDL-C oxidation inhibition. Both extracts effectively inhibited Cu(2+)-induced LDL-C oxidation. IC(50) of QAE and TAE for LDL-C oxidation products were 0.06-8.29 mg/L and 29.58-95.49 mg/L, respectively. Quercetin compounds, chlorogenic acid and phloridzin could contribute more to the effectiveness of QAE at physiological concentrations. The three in vivo quercetin metabolites; quercetin-3'-sulfate, quercetin-3-glucuronic acid and isorhamnetin-3-glucuronic acid were effective at physiological concentrations and therefore, QAE can be effective in LDL-C oxidation inhibition under physiological conditions. Constituent TAE compounds did not perform well under Cu(2+)-induction. Overall, both extracts effectively inhibited LDL-C oxidation in vitro. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. A large blood pressure-raising effect of nitric oxide synthase inhibition in humans

    NASA Technical Reports Server (NTRS)

    Sander, M.; Chavoshan, B.; Victor, R. G.; Blomqvist, C. G. (Principal Investigator)

    1999-01-01

    In experimental animals, systemic administration of nitric oxide synthase (NOS) inhibitors causes large increases in blood pressure that are in part sympathetically mediated. The aim of this study was to determine the extent to which these conclusions can be extrapolated to humans. In healthy normotensive humans, we measured blood pressure in response to two NOS inhibitors, NG-monomethyl-L-arginine (L-NMMA) and NG-nitro-L-arginine methyl ester (L-NAME), the latter of which recently became available for use in humans. The major new findings are 3-fold. First, L-NAME produced robust increases in blood pressure that were more than 2 times larger than those previously reported in humans with L-NMMA and approximated those seen in experimental animals. L-NAME (4 mg/kg) raised mean arterial pressure by 24+/-2 mm Hg (n=27, P<0.001), whereas in subjects who received both inhibitors, a 12-fold higher dose of L-NMMA (50 mg/kg) raised mean arterial pressure by 15+/-2 mm Hg (n=4, P<0.05 vs L-NAME). Second, the L-NAME-induced increases in blood pressure were caused specifically by NOS inhibition because they were reversed by L-arginine (200 mg/kg, n=12) but not D-arginine (200 mg/kg, n=6) and because NG-nitro-D-arginine methyl ester (4 mg/kg, n=5) had no effect on blood pressure. Third, in humans, there is an important sympathetic component to the blood pressure-raising effect of NOS inhibition. alpha-Adrenergic blockade with phentolamine (0.2 mg/kg, n=9) attenuated the L-NAME-induced increase in blood pressure by 40% (P<0.05). From these data, we conclude that pharmacological inhibition of NOS causes large increases in blood pressure that are in part sympathetically mediated in humans as well as experimental animals.

  3. Activation of histamine H3 receptors in human nasal mucosa inhibits sympathetic vasoconstriction.

    PubMed

    Varty, LoriAnn M; Gustafson, Eric; Laverty, Maureen; Hey, John A

    2004-01-19

    The peripheral histamine H3 receptor is a presynaptic heterologous receptor located on postganglionic sympathetic nerve fibers innervating sympathetic effector systems such as blood vessels and the heart. An extensive body of evidence shows that activation of the histamine H3 receptor attenuates sympathetic tone by presynaptic inhibition of noradrenaline release. It is proposed that this sympathoinhibitory action, in vivo, leads to reduced vasoconstriction, thereby eliciting a vasodilatory effect. In humans, the peripheral histamine H3 receptor has also been shown to exert a sympathoinhibitory function on specific peripheral autonomic effector systems. For example, human saphenous vein and heart possess functional presynaptic histamine H3 receptors on the sympathetic nerve terminals that upon activation decrease the sympathetic tone to these respective organs. The present studies were conducted to define the role of histamine H3 receptors on neurogenic sympathetic vasoconstrictor responses in human nasal turbinate mucosa. Contractility studies were conducted to evaluate the effect of histamine H3 receptor activation on sympathetic vasoconstriction in surgically isolated human nasal turbinate mucosa. We found that the histamine H3 receptor agonist, (R)-alpha-methylhistamine (30 and 300 nM), inhibited electrical field stimulation-induced (neurogenic) sympathetic vasoconstriction in a concentration-dependent fashion. Pretreatment with the selective histamine H3 receptor antagonist, clobenpropit (100 nM), blocked the sympathoinhibitory effect of (R)-alpha-methylhistamine on the neurogenic sympathetic vasoconstriction. In addition, analysis of Taqman mRNA expression studies showed a specific, high level of distribution of the histamine H3 receptor localized in the human nasal mucosa. Taken together, these studies indicate that histamine H3 receptors modulate vascular contractile responses in human nasal mucosa most likely by inhibiting noradrenaline release from

  4. A large blood pressure-raising effect of nitric oxide synthase inhibition in humans

    NASA Technical Reports Server (NTRS)

    Sander, M.; Chavoshan, B.; Victor, R. G.; Blomqvist, C. G. (Principal Investigator)

    1999-01-01

    In experimental animals, systemic administration of nitric oxide synthase (NOS) inhibitors causes large increases in blood pressure that are in part sympathetically mediated. The aim of this study was to determine the extent to which these conclusions can be extrapolated to humans. In healthy normotensive humans, we measured blood pressure in response to two NOS inhibitors, NG-monomethyl-L-arginine (L-NMMA) and NG-nitro-L-arginine methyl ester (L-NAME), the latter of which recently became available for use in humans. The major new findings are 3-fold. First, L-NAME produced robust increases in blood pressure that were more than 2 times larger than those previously reported in humans with L-NMMA and approximated those seen in experimental animals. L-NAME (4 mg/kg) raised mean arterial pressure by 24+/-2 mm Hg (n=27, P<0.001), whereas in subjects who received both inhibitors, a 12-fold higher dose of L-NMMA (50 mg/kg) raised mean arterial pressure by 15+/-2 mm Hg (n=4, P<0.05 vs L-NAME). Second, the L-NAME-induced increases in blood pressure were caused specifically by NOS inhibition because they were reversed by L-arginine (200 mg/kg, n=12) but not D-arginine (200 mg/kg, n=6) and because NG-nitro-D-arginine methyl ester (4 mg/kg, n=5) had no effect on blood pressure. Third, in humans, there is an important sympathetic component to the blood pressure-raising effect of NOS inhibition. alpha-Adrenergic blockade with phentolamine (0.2 mg/kg, n=9) attenuated the L-NAME-induced increase in blood pressure by 40% (P<0.05). From these data, we conclude that pharmacological inhibition of NOS causes large increases in blood pressure that are in part sympathetically mediated in humans as well as experimental animals.

  5. Mutual Regioselective Inhibition of Human UGT1A1-Mediated Glucuronidation of Four Flavonoids

    PubMed Central

    Ma, Guo; Wu, Baojian; Gao, Song; Yang, Zhen; Ma, Yong; Hu, Ming

    2013-01-01

    UDP-glucuronosyltransferase (UGT) 1A1-catalyzed glucuronidation is an important elimination pathway of flavonoids, and mutually inhibitory interactions may occur when two or more flavonoids are co-administered. Our recent research suggested that glucuronidation of flavonoids displayed distinct positional preferences, but whether this will lead to the mutually regioselective inhibition of UGT1A1-mediated glucuronidation of flavonoids is unknown. Therefore, we chose three monohydroxyflavone isomers 3-hydroxyflavone (3HF), 7-hydroxyflavone (7HF), 4′-hydroxyflavone (4′HF) and one trihydroxyflavone 3,7,4′-trihydroxyflavone (3,7,4′THF) as the model compounds to characterize the possible mutually regioselective inhibition of glucuronidation using expressed human UGT1A1. Apparent kinetic parameters [e.g., reaction velocity (V), Michaelis-Menten constant (Km), maximum rate of metabolism (Vmax), concentration at which inhibitor achieve 50% inhibition or IC50] and the Lineweaver-Burk plots were used to evaluate the apparent kinetic mechanisms of inhibition of glucuronidation. The results showed that UGT1A1-mediated glucuronidation of three monohydroxyflavones (i.e., 3HF, 7HF and 4′HF) and 3,7,4′THF was mutually inhibitory, and the mechanisms of inhibition appeared to be the mixed-typed inhibition. Specifically, the inhibitory effects displayed certain positional preference. Glucuronidation of 3HF was more easily inhibited by 3,7,4′THF than that of 7HF or 4′HF. Compared to 7-O-glucuronidation of 3,7,4′THF, 3-O-glucuronidation of 3,7,4′THF was more inhibited by 3HF and 4′HF, whereas glucuronidation at both 3-OH and 7-OH positions of 3,7,4′THF was more easily inhibited by 7HF than by 3HF and 4′HF. In conclusion, 3HF, 7HF, 4′HF and 3,7,4′THF were both substrates and inhibitors of UGT1A1, and they exhibited mutually regioselective inhibition of UGT1A1-mediated glucuronidation via a mixed-type inhibitory mechanism. PMID:23786524

  6. Palau'amine and related oroidin alkaloids dibromophakellin and dibromophakellstatin inhibit the human 20S proteasome.

    PubMed

    Lansdell, Theresa A; Hewlett, Nicole M; Skoumbourdis, Amanda P; Fodor, Matthew D; Seiple, Ian B; Su, Shun; Baran, Phil S; Feldman, Ken S; Tepe, Jetze J

    2012-05-25

    We report herein that the oroidin-derived alkaloids palau'amine (1), dibromophakellin (2), and dibromophakellstatin (3) inhibit the proteolytic activity of the human 20S proteasome as well as the (i)20S immunoproteasome catalytic core. Palau'amine is found to prevent the degradation of ubiquitinylated proteins, including IκBα, in cell culture, which may be indicative of the potential mechanism by which these agents exhibit their exciting cytotoxic and immunosuppressive properties.

  7. Human α-Defensins Inhibit Hemolysis Mediated by Cholesterol-Dependent Cytolysins▿

    PubMed Central

    Lehrer, Robert I.; Jung, Grace; Ruchala, Piotr; Wang, Wei; Micewicz, Ewa D.; Waring, Alan J.; Gillespie, Eugene J.; Bradley, Kenneth A.; Ratner, Adam J.; Rest, Richard F.; Lu, Wuyuan

    2009-01-01

    Many pathogenic gram-positive bacteria release exotoxins that belong to the family of cholesterol-dependent cytolysins. Here, we report that human α-defensins HNP-1 to HNP-3 acted in a concentration-dependent manner to protect human red blood cells from the lytic effects of three of these exotoxins: anthrolysin O (ALO), listeriolysin O, and pneumolysin. HD-5 was very effective against listeriolysin O but less effective against the other toxins. Human α-defensins HNP-4 and HD-6 and human β-defensin-1, -2, and -3 lacked protective ability. HNP-1 required intact disulfide bonds to prevent toxin-mediated hemolysis. A fully linearized analog, in which all six cysteines were replaced by aminobutyric acid (Abu) residues, showed greatly reduced binding and protection. A partially unfolded HNP-1 analog, in which only cysteines 9 and 29 were replaced by Abu residues, showed intact ALO binding but was 10-fold less potent in preventing hemolysis. Surface plasmon resonance assays revealed that HNP-1 to HNP-3 bound all three toxins at multiple sites and also that solution-phase HNP molecules could bind immobilized HNP molecules. Defensin concentrations that inhibited hemolysis by ALO and listeriolysin did not prevent these toxins from binding either to red blood cells or to cholesterol. Others have shown that HNP-1 to HNP-3 inhibit lethal toxin of Bacillus anthracis, toxin B of Clostridium difficile, diphtheria toxin, and exotoxin A of Pseudomonas aeruginosa; however, this is the first time these defensins have been shown to inhibit pore-forming toxins. An “ABCDE mechanism” that can account for the ability of HNP-1 to HNP-3 to inhibit so many different exotoxins is proposed. PMID:19581399

  8. Inhibition of human TDP2 by deazaflavins | Center for Cancer Research

    Cancer.gov

    Tyrosyl-DNA phosphodiesterase 2 repairs irreversible topoisomerase II-mediated cleavage complexes generated by anticancer topoisomerase-targeted drugs and processes replication intermediates for picornaviruses (VPg unlinkase) and hepatitis B virus. There is currently no TDP2 inhibitor in clinical development. Here, we report a series of deazaflavin derivatives that selectively inhibit the human TDP2 enzyme in a competitive manner both with recombinant and native TDP2. We show that mouse, fish, and C.

  9. In vitro inhibition of human erythrocyte glutathione reductase by some new organic nitrates.

    PubMed

    Sentürk, Murat; Talaz, Oktay; Ekinci, Deniz; Cavdar, Hüseyin; Küfrevioğlu, Omer Irfan

    2009-07-01

    Glutathione reductase (GR), is responsible for the existence of GSH molecule, a crucial antioxidant against oxidative stress reagents. The antimalarial activities of some redox active compounds are attributed to their inhibition of antioxidant flavoenzyme glutathione reductase, and inhibitors are therefore expected to be useful for the treatment of malaria. Twelve organic nitrate derivatives were synthesized and treated with human erythrocyte GR. The molecules were identified as strong GR inhibitors and novel antimalaria candidates.

  10. Intestinal inhibition of the Na+/H+ exchanger 3 prevents cardiorenal damage in rats and inhibits Na+ uptake in humans.

    PubMed

    Spencer, Andrew G; Labonte, Eric D; Rosenbaum, David P; Plato, Craig F; Carreras, Christopher W; Leadbetter, Michael R; Kozuka, Kenji; Kohler, Jill; Koo-McCoy, Samantha; He, Limin; Bell, Noah; Tabora, Jocelyn; Joly, Kristin M; Navre, Marc; Jacobs, Jeffrey W; Charmot, Dominique

    2014-03-12

    The management of sodium intake is clinically important in many disease states including heart failure, kidney disease, and hypertension. Tenapanor is an inhibitor of the sodium-proton (Na(+)/H(+)) exchanger NHE3, which plays a prominent role in sodium handling in the gastrointestinal tract and kidney. When administered orally to rats, tenapanor acted exclusively in the gastrointestinal tract to inhibit sodium uptake. We showed that the systemic availability of tenapanor was negligible through plasma pharmacokinetic studies, as well as autoradiography and mass balance studies performed with (14)C-tenapanor. In humans, tenapanor reduced urinary sodium excretion by 20 to 50 mmol/day and led to an increase of similar magnitude in stool sodium. In salt-fed nephrectomized rats exhibiting hypervolemia, cardiac hypertrophy, and arterial stiffening, tenapanor reduced extracellular fluid volume, left ventricular hypertrophy, albuminuria, and blood pressure in a dose-dependent fashion. We observed these effects whether tenapanor was administered prophylactically or after disease was established. In addition, the combination of tenapanor and the blood pressure medication enalapril improved cardiac diastolic dysfunction and arterial pulse wave velocity relative to enalapril monotherapy in this animal model. Tenapanor prevented increases in glomerular area and urinary KIM-1, a marker of renal injury. The results suggest that therapeutic alteration of sodium transport in the gastrointestinal tract instead of the kidney--the target of current drugs--could lead to improved sodium management in renal disease.

  11. DA-9601 inhibits activation of the human mast cell line HMC-1 through inhibition of NF-kappaB.

    PubMed

    Lee, S; Park, H-H; Son, H-Y; Ha, J-H; Lee, M-G; Oh, T-Y; Sohn, D H; Jeong, T C; Lee, S H; Son, J-K; Lee, S G; Jun, C-D; Kim, S-H

    2007-03-01

    Mast cell-mediated allergic inflammation is involved in many diseases such as asthma, sinusitis, and rheumatoid arthritis. Mast cells induce synthesis and production of pro-inflammatory cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6 with immune regulatory properties. The formulated ethanol extract of Artemisia asiatica Nakai (DA-9601) has been reported to have antioxidative and anti-inflammatory activities. In this report, we investigated the effect of DA-9601 on the expression of pro-inflammatory cytokines by the activated human mast cell line HMC-1 and studied its possible mechanisms of action. DA-9601 dose-dependently decreased the gene expression and production of TNF-alpha, IL-1beta, and IL-6 on phorbol 12-myristate 13-acetate (PMA)- and calcium ionophore A23187-stimulated HMC-1 cells. In addition, DA-9601 attenuated PMA- and A23187-induced activation of NF-kappaB as indicated by inhibition of degradation of IkappaBalpha, nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. Our in vitro studies provide evidence that DA-9601 might contribute to the treatment of mast cell-derived allergic inflammatory diseases.

  12. Vaginal Lactobacillus Inhibits HIV-1 Replication in Human Tissues Ex Vivo

    PubMed Central

    Ñahui Palomino, Rogers A.; Zicari, Sonia; Vanpouille, Christophe; Vitali, Beatrice; Margolis, Leonid

    2017-01-01

    Lactobacillus species, which dominate vaginal microbiota of healthy reproductive-age women, lower the risks of sexually transmitted infections, including the risk of human immunodeficiency virus (HIV) acquisition. The exact mechanisms of this protection remain to be understood. Here, we investigated these mechanisms in the context of human cervico-vaginal and lymphoid tissues ex vivo. We found that all six Lactobacillus strains tested in these systems significantly suppressed HIV type-1 (HIV-1) infection. We identified at least three factors that mediated this suppression: (i) Acidification of the medium. The pH of the undiluted medium conditioned by lactobacilli was between 3.8 and 4.6. Acidification of the culture medium with hydrochloric acid (HCl) to this pH in control experiments was sufficient to abrogate HIV-1 replication. However, the pH of the Lactobacillus-conditioned medium (CM) diluted fivefold, which reached ∼6.9, was also suppressive for HIV-1 infection, while in control experiments HIV-1 infection was not abrogated when the pH of the medium was brought to 6.9 through the use of HCl. This suggested the existence of other factors responsible for HIV-1 inhibition by lactobacilli. (ii) Lactic acid. There was a correlation between the concentration of lactic acid in the Lactobacillus-CM and its ability to suppress HIV-1 infection in human tissues ex vivo. Addition of lactic acid isomers D and L to tissue culture medium at the concentration that corresponded to their amount released by lactobacilli resulted in HIV-1 inhibition. Isomer L was produced in higher quantities than isomer D and was mostly responsible for HIV-1 inhibition. These results indicate that lactic acid, in particular its L-isomer, inhibits HIV-1 independently of lowering of the pH. (iii) Virucidal effect. Incubation of HIV-1 in Lactobacillus-CM significantly suppressed viral infectivity for human tissues ex vivo. Finally, lactobacilli adsorb HIV-1, serving as a sink decreasing the

  13. Phenoxy herbicides and fibrates potently inhibit the human chemosensory receptor subunit T1R3

    PubMed Central

    Maillet, Emeline L.; Margolskee, Robert F.; Mosinger, Bedrich

    2009-01-01

    We show that phenoxy-auxin herbicides and lipid-lowering fibrates inhibit human but not rodent T1R3. T1R3 as a co-receptor in taste cells responds to sweet compounds and amino-acids; in endocrine cells of gut and pancreas T1R3 contributes to glucose sensing. Thus, certain effects of fibrates in treating hyperlipidemia and type II diabetes may be via actions on T1R3. Likewise, phenoxy-herbicides may have adverse metabolic effects in humans that would have gone undetected in studies on rodents. PMID:19817384

  14. Salidroside inhibits the growth of human breast cancer in vitro and in vivo.

    PubMed

    Zhao, Gang; Shi, Aiping; Fan, Zhimin; Du, Ye

    2015-05-01

    Salidroside has been identified as one of the most potent compounds isolated from the plant Rhodiola rosea, and was found to have several important biological properties, including antioxidant and anti-inflammatory activity; however, its anticancer effects are poorly understood. Thus, the present study focused on evaluating the effects of purified salidroside on the growth of human breast cancer in vitro and in vivo, and on further investigating its possible molecular mechanisms. The human breast cancer cell line, MCF-7, was incubated with various concentrations of salidroside, and cell proliferation, colony formation, cell cycle distribution, apoptosis, migration and invasion were assayed by several in vitro approaches. As a result, it was found that salidroside treatment significantly inhibited cell proliferation, colony formation, migration and invasion, as well as induced cell apoptosis and cell cycle arrest at the G0/G1 phase in vitro. In addition, we also evaluated the effect of salidroside on tumor growth in a nude mouse model, and found that salidroside treatment significantly suppressed tumor growth in vivo. We also further disclosed that salidroside treatment significantly inhibited the intracellular reactive oxygen species (ROS) formation and MAPK pathway activation, which may contribute to the inhibition of tumor growth of breast cancer and reduction of oxidative stress. In conclusion, these findings suggest that salidroside may be a promising candidate target for the prevention and treatment of human breast cancer.

  15. Inhibition of adipocytogenesis by canonical WNT signaling in human mesenchymal stem cells

    SciTech Connect

    Shen, Longxiang; Glowacki, Julie; Zhou, Shuanhu

    2011-08-01

    The WNT signaling pathway plays important roles in the self-renewal and differentiation of mesenchymal stem cells (MSCs). Little is known about WNT signaling in adipocyte differentiation of human MSCs. In this study, we tested the hypothesis that canonical and non-canonical WNTs differentially regulate in vitro adipocytogenesis in human MSCs. The expression of adipocyte gene PPAR{gamma}2, lipoprotein lipase, and adipsin increased during adipocytogenesis of hMSCs. Simultaneously, the expression of canonical WNT2, 10B, 13, and 14 decreased, whereas non-canonical WNT4 and 11 increased, and WNT5A was unchanged. A small molecule WNT mimetic, SB-216763, increased accumulation of {beta}-catenin protein, inhibited induction of WNT4 and 11 and inhibited adipocytogenesis. In contrast, knockdown of {beta}-catenin with siRNA resulted in spontaneous adipocytogenesis. These findings support the view that canonical WNT signaling inhibits and non-canonical WNT signaling promotes adipocytogenesis in adult human marrow-derived mesenchymal stem cells.

  16. Nongenomic signaling of the retinoid X receptor through binding and inhibiting Gq in human platelets

    PubMed Central

    Moraes, Leonardo A.; Swales, Karen E.; Wray, Jessica A.; Damazo, Amilcar; Gibbins, Jonathan M.; Warner, Timothy D.

    2007-01-01

    Retinoid X receptors (RXRs) are important transcriptional nuclear hormone receptors, acting as either homodimers or the binding partner for at least one fourth of all the known human nuclear receptors. Functional nongenomic effects of nuclear receptors are poorly understood; however, recently peroxisome proliferator-activated receptor (PPAR) γ, PPARβ, and the glucocorticoid receptor have all been found active in human platelets. Human platelets express RXRα and RXRβ. RXR ligands inhibit platelet aggregation and TXA2 release to ADP and the TXA2 receptors, but only weakly to collagen. ADP and TXA2 both signal via the G protein, Gq. RXR rapidly binds Gq but not Gi/z/o/t/gust in a ligand-dependent manner and inhibits Gq-induced Rac activation and intracellular calcium release. We propose that RXR ligands may have beneficial clinical actions through inhibition of platelet activation. Furthermore, our results demonstrate a novel nongenomic mode for nuclear receptor action and a functional cross-talk between G-protein and nuclear receptor signaling families. PMID:17213293

  17. Diosgenin inhibits IL-1β-induced expression of inflammatory mediators in human osteoarthritis chondrocytes

    PubMed Central

    Wang, Leisheng; Ma, Tian; Zheng, Yanpin; Lv, Shiqiao; Li, Yu; Liu, Shaoxian

    2015-01-01

    It is well known that the inflammatory cytokines play important roles in osteoarthritis (OA). Diosgenin is a steroidal saponin found in several plants including Solanum and Dioscorea species and possesses diverse biological activities including anti-inflammatory properties. However, the role of diosgenin in inflammatory responses in OA chondrocytes is still unclear. Therefore, in this study, we investigated the anti-inflammatory properties of diosgenin in human OA chondrocytes. We found that diosgenin inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) induced by interleukin-1-beta (IL-1β). Diosgenin significantly inhibited the IL-1β-stimulated expression of metalloproteinase-3 (MMP-3), MMP-13, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in human OA chondrocytes. In addition, diosgenin suppressed the degradation of IκB-α in IL-1β-induced human OA chondrocytes. Taken together, this study showed that diosgenin can effectively inhibit the IL-1β-induced expression of inflammatory mediators, suggesting that diosgenin may be a potential agent in the treatment of OA. PMID:26191174

  18. Inhibition of Human Dendritic Cell Activation by Hydroethanolic But Not Lipophilic Extracts of Turmeric (Curcuma longa)

    PubMed Central

    Krasovsky, Joseph; Chang, David H.; Deng, Gary; Yeung, Simon; Lee, Mavis; Leung, Ping Chung; Cunningham-Rundles, Susanna; Cassileth, Barrie; Dhodapkar, Madhav V.

    2015-01-01

    Turmeric has been extensively utilized in Indian and Chinese medicine for its immune-modulatory properties. Dendritic cells (DCs) are antigen-presenting cells specialized to initiate and regulate immunity. The ability of DCs to initiate immunity is linked to their activation status. The effects of turmeric on human DCs have not been studied. Here we show that hydroethanolic (HEE) but not lipophilic “supercritical” extraction (SCE) of turmeric inhibits the activation of human DCs in response to inflammatory cytokines. Treatment of DCs with HEE also inhibits the ability of DCs to stimulate the mixed lymphocyte reaction (MLR). Importantly, the lipophilic fraction does not synergize with the hydroethanolic fraction for the ability of inhibiting DC maturation. Rather, culturing of DCs with the combination of HEE and SCE leads to partial abrogation of the effects of HEE on the MLR initiated by DCs. These data provide a mechanism for the anti-inflammatory properties of turmeric. However, they suggest that these extracts are not synergistic and may contain components with mutually antagonistic effects on human DCs. Harnessing the immune effects of turmeric may benefit from specifically targeting the active fractions. PMID:19034830

  19. Inhibition of human dendritic cell activation by hydroethanolic but not lipophilic extracts of turmeric (Curcuma longa).

    PubMed

    Krasovsky, Joseph; Chang, David H; Deng, Gary; Yeung, Simon; Lee, Mavis; Leung, Ping Chung; Cunningham-Rundles, Susanna; Cassileth, Barrie; Dhodapkar, Madhav V

    2009-03-01

    Turmeric has been extensively utilized in Indian and Chinese medicine for its immune-modulatory properties. Dendritic cells (DCs) are antigen-presenting cells specialized to initiate and regulate immunity. The ability of DCs to initiate immunity is linked to their activation status. The effects of turmeric on human DCs have not been studied. Here we show that hydroethanolic (HEE) but not lipophilic "supercritical" extraction (SCE) of turmeric inhibits the activation of human DCs in response to inflammatory cytokines. Treatment of DCs with HEE also inhibits the ability of DCs to stimulate the mixed lymphocyte reaction (MLR). Importantly, the lipophilic fraction does not synergize with the hydroethanolic fraction for the ability of inhibiting DC maturation. Rather, culturing of DCs with the combination of HEE and SCE leads to partial abrogation of the effects of HEE on the MLR initiated by DCs. These data provide a mechanism for the anti-inflammatory properties of turmeric. However, they suggest that these extracts are not synergistic and may contain components with mutually antagonistic effects on human DCs. Harnessing the immune effects of turmeric may benefit from specifically targeting the active fractions.

  20. Imipramine Inhibits Chikungunya Virus Replication in Human Skin Fibroblasts through Interference with Intracellular Cholesterol Trafficking.

    PubMed

    Wichit, Sineewanlaya; Hamel, Rodolphe; Bernard, Eric; Talignani, Loïc; Diop, Fodé; Ferraris, Pauline; Liegeois, Florian; Ekchariyawat, Peeraya; Luplertlop, Natthanej; Surasombatpattana, Pornapat; Thomas, Frédéric; Merits, Andres; Choumet, Valérie; Roques, Pierre; Yssel, Hans; Briant, Laurence; Missé, Dorothée

    2017-06-09

    Chikungunya virus (CHIKV) is an emerging arbovirus of the Togaviridae family that poses a present worldwide threat to human in the absence of any licensed vaccine or antiviral treatment to control viral infection. Here, we show that compounds interfering with intracellular cholesterol transport have the capacity to inhibit CHIKV replication in human skin fibroblasts, a major viral entry site in the human host. Pretreatment of these cells with the class II cationic amphiphilic compound U18666A, or treatment with the FDA-approved antidepressant drug imipramine resulted in a near total inhibition of viral replication and production at the highest concentration used without any cytotoxic effects. Imipramine was found to affect both the fusion and replication steps of the viral life cycle. The key contribution of cholesterol availability to the CHIKV life cycle was validated further by the use of fibroblasts from Niemann-Pick type C (NPC) patients in which the virus was unable to replicate. Interestingly, imipramine also strongly inhibited the replication of several Flaviviridae family members, including Zika, West Nile and Dengue virus. Together, these data show that this compound is a potential drug candidate for anti-arboviral treatment.

  1. Parabens inhibit human skin estrogen sulfotransferase activity: possible link to paraben estrogenic effects.

    PubMed

    Prusakiewicz, Jeffery J; Harville, Heather M; Zhang, Yanhua; Ackermann, Chrisita; Voorman, Richard L

    2007-04-11

    Parabens (p-hydroxybenzoate esters) are a group of widely used preservatives in topically applied cosmetic and pharmaceutical products. Parabens display weak associations with the estrogen receptors in vitro or in cell based models, but do exhibit estrogenic effects in animal models. It is our hypothesis that parabens exert their estrogenic effects, in part, by elevating levels of estrogens through inhibition of estrogen sulfotransferases (SULTs) in skin. We report here the results of a structure-activity-relationship of parabens as inhibitors of estrogen sulfation in human skin cytosolic fractions and normal human epidermal keratinocytes. Similar to reports of paraben estrogenicity and estrogen receptor affinity, the potency of SULT inhibition increased as the paraben ester chain length increased. Butylparaben was found to be the most potent of the parabens in skin cytosol, yielding an IC(50) value of 37+/-5 microM. Butylparaben blocked the skin cytosol sulfation of estradiol and estrone, but not the androgen dehydroepiandrosterone. The parabens were also tested as inhibitors of SULT activity in a cellular system, with normal human epidermal keratinocytes. The potency of butylparaben increased three-fold in these cells relative to the IC(50) value from skin cytosol. Overall, these results suggest chronic topical application of parabens may lead to prolonged estrogenic effects in skin as a result of inhibition of estrogen sulfotransferase activity. Accordingly, the skin anti-aging benefits of many topical cosmetics and pharmaceuticals could be derived, in part, from the estrogenicity of parabens.

  2. Inhibition of P-glycoprotein activity in human leukemic cells by mifepristone.

    PubMed

    Fardel, O; Courtois, A; Drenou, B; Lamy, T; Lecureur, V; le Prisé, P Y; Fauchet, R

    1996-08-01

    The antiprogestatin drug mifepristone has previously been shown to potentiate anti-cancer drug activity in rodent multidrug-resistant cell lines through inhibition of P-glycoprotein (P-gp) function. In order to characterize P-gp-mifepristone interactions in human tumoral cells, we have studied the effect of the antiprogestatin agent on P-gp activity in human CD34+ leukemic cells known to display high levels of P-gp-related drug efflux. P-gp-mediated transport of the fluorescent dye rhodamine 123 occurring in the CD34+ KG1a myeloid leukemia cell line was found to be strongly inhibited by mifepristone in a dose-dependent manner. Similarly to verapamil, a well-known chemosensitizer agent, the antiprogestatin drug increased doxorubicin cytotoxicity in KG1a cells. Mifepristone, when used at a 10 microM concentration thought to be achievable in vivo without major toxicity, was also able to markedly decrease cellular rhodamine 123 efflux occurring in CD34+ blast cells isolated from six patients suffering from myeloid acute leukemias. These results thus indicate that mifepristone can strongly inhibit P-gp activity in human cells, including tumoral cells freshly isolated from patients, therefore suggesting that the clinical use of this compound may contribute to down-modulate P-gp-mediated drug resistance.

  3. Inhibition of human liver aldehyde oxidase: implications for potential drug-drug interactions.

    PubMed

    Barr, John T; Jones, Jeffrey P

    2011-12-01

    During the course of our research efforts to understand the kinetics of human aldehyde oxidase as a xenobiotic-clearing enzyme, we investigated the effect of eight different inhibitors on the oxidation of the probe substrate phthalazine. Saturation kinetic parameters for phthalazine oxidation in human liver cytosol were found to be the following: K(m) = 8.0 ± 0.4 μM and V(max) = 4.3 ± 0.1 nmol · min(-1) · mg protein(-1). Inhibitory potency of the inhibitors tested ranged from 0.1 to 5 μM. Of the eight different inhibitor compounds tested, seven were observed to inhibit through a mixed mode and one through a strictly competitive mode. A ratio of the K(ii) and K(is) values was used to assess the relative competitiveness of each inhibitor. For the mixed inhibitors, the mode of inhibition varied from mostly uncompetitive to predominantly competitive (K(ii)/K(is) values ranging from 0.1 to 15). The implications for potential drug-drug interactions and inhibition mechanism are discussed. We found two inhibitors, clozapine and chlorpromazine, that have a moderate predicted risk of drug-drug interactions based on the K(i) value relative to the inhibitor concentration in human plasma, having a calculated [I]/K(i) value of 0.4 and 0.8, respectively.

  4. Gefitinib causes growth arrest and inhibition of metastasis in human chondrosarcoma cells.

    PubMed

    Song, Jian; Zhu, Jiaxue; Zhao, Qiang; Tian, Baofang

    2015-01-01

    Chondrosarcomas are primary malignant cartilage-forming tumors of bone which are not responsive either to chemotherapy or radiation treatment and display potent capacity to invade locally and cause distant metastasis. Epidermal growth factor receptor (EGFR) pathway plays an important role in the development and progression of many cancers. However, the effect of EGFR inhibitor gefitinib on cell growth and metastasis in human chondrosarcoma cells is largely unknown. Features of the protein expression of EGFR in 3 human chondrosarcoma cell lines JJ2012, SW1353 and OUMS27 were analyzed. The inhibitory effects of EGFR inhibitor gefitinib on cell proliferation, cell cycle and metastasis were assessed by using MTS, flow cytometry and migration assays, respectively. The expression of metastasis-related proteins was evaluated by western blotting. All the three human chondrosarcoma cell lines expressed EGFR protein. Gefitinib significantly inhibited the growth, induced cell cycle arrest and decreased the migra- tion ability of human chondrosarcoma cells. In addition, gefitinib also reduced the expression of metastasis-related proteins, basic fibroblast growth factor (bFGF), matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9). The discovery that gefitinib inhibited the proliferation and reduced the metastatic capacity of chondrosarcoma cells may help increase the understanding of the mechanism underlying human chondrosarcoma growth and metastasis. Thus, gefitinib may represent a promising agent for controlling chondrosarcoma proliferation and metastasis.

  5. A humanized anti-DLL4 antibody promotes dysfunctional angiogenesis and inhibits breast tumor growth

    PubMed Central

    Jia, Xuelian; Wang, Wenyi; Xu, Zhuobin; Wang, Shijing; Wang, Tong; Wang, Min; Wu, Min

    2016-01-01

    Blockage of Delta-like 4 (DLL4)-directed Notch signaling induces excessive tip cell formation and endothelial proliferation resulting in dysfunctional angiogenesis in tumors. MMGZ01, as a murine anti-human DLL4 monoclonal antibody, specifically binds to human DLL4 and blocks Notch pathway. Here, the structure of MMGZ01 variable fragment (Fv) was established and framework region (FR) residues which supported complementarily determining region (CDR) loop conformation were identified. Important residues interactions were also identified through docking MMGZ01 Fv with antigen epitope in DLL4. To humanize the murine antibody, we modified MMGZ01 Fv through CDR grafting and the reconstructed antibody (H3L2) maintained similar structure and binding affinity to parental MMGZ01 after back mutation of 12 canonical murine residues in the FRs. Meanwhile, H3L2 promoted human umbilical vein endothelial cell (HUVEC) proliferation through inhibiting DLL4-directed Notch pathway. Moreover, in MDA-MB-231-bearing nude mice, H3L2 induced dysfunctional angiogenesis and tumor cell apoptosis and showed superior anti-tumor activity. In conclusion, H3L2 is an ideal humanized antibody that inhibits tumor growth through targeting DLL4-Notch pathway and has attracting potentials for clinical applications. PMID:27301650

  6. Inhibition of fibroblast growth factor receptor 3-dependent lung adenocarcinoma with a human monoclonal antibody

    PubMed Central

    Yin, Yongjun; Ren, Xiaodi; Smith, Craig; Guo, Qianxu; Malabunga, Maria; Guernah, Ilhem; Zhang, Yiwei; Shen, Juqun; Sun, Haijun; Chehab, Nabil; Loizos, Nick; Ludwig, Dale L.; Ornitz, David M.

    2016-01-01

    ABSTRACT Activating mutations in fibroblast growth factor receptor 3 (FGFR3) have been identified in multiple types of human cancer and in congenital birth defects. In human lung cancer, fibroblast growth factor 9 (FGF9), a high-affinity ligand for FGFR3, is overexpressed in 10% of primary resected non-small cell lung cancer (NSCLC) specimens. Furthermore, in a mouse model where FGF9 can be induced in lung epithelial cells, epithelial proliferation and ensuing tumorigenesis is dependent on FGFR3. To develop new customized therapies for cancers that are dependent on FGFR3 activation, we have used this mouse model to evaluate a human monoclonal antibody (D11) with specificity for the extracellular ligand-binding domain of FGFR3, that recognizes both human and mouse forms of the receptor. Here, we show that D11 effectively inhibits signaling through FGFR3 in vitro, inhibits the growth of FGFR3-dependent FGF9-induced lung adenocarcinoma in mice, and reduces tumor-associated morbidity. Given the potency of FGF9 in this mouse model and the absolute requirement for signaling through FGFR3, this study validates the D11 antibody as a potentially useful and effective reagent for treating human cancers or other pathologies that are dependent on activation of FGFR3. PMID:27056048

  7. Sildenafil inhibits the growth of human colorectal cancer in vitro and in vivo

    PubMed Central

    Mei, Xiao-Long; Yang, Yang; Zhang, Yao-Jun; Li, Yong; Zhao, Jin-Ming; Qiu, Jian-Ge; Zhang, Wen-Ji; Jiang, Qi-Wei; Xue, You-Qiu; Zheng, Di-Wei; Chen, Yao; Qin, Wu-Ming; Wei, Meng-Ning; Shi, Zhi

    2015-01-01

    Colorectal cancer is the third most common human cancer with frequent overexpression of the cGMP-specific phosphodiesterase 5 (PDE5). In the present study, we investigated that the anticancer effect of sildenafil on human colorectal cancer in vitro and in vivo, which is a potent and selective inhibitor of PDE5 for the treatment of erectile dysfunction and pulmonary arterial hypertension in the clinic. Sildenafil significantly induced cell growth inhibition, cell cycle arrest and apoptosis of human colorectal cancer with increased intracellular reactive oxidative specie (ROS) levels, which were accompanied by obvious alterations of related proteins such as CDKs, Cyclins and PARP etc. Pretreatment with ROS scavenger N-acetyl-L-cysteine could reverse sildenafil-induced ROS accumulation and cell apoptosis. Inhibition of the activity of protein kinase G with KT-5823 could enhance sildenafil-induced apoptosis. Furthermore, sildenafil caused the reduction of xenograft models of human colorectal cancer in nude mice. Overall, these findings suggest that sildenafil has the potential to be used for treatment of human colorectal cancer. PMID:26807313

  8. Peroxisome proliferator-activated receptor gamma activation inhibits progesterone-stimulated human MUC1 expression.

    PubMed

    Wang, Peng; Dharmaraj, Neeraja; Brayman, Melissa J; Carson, Daniel D

    2010-07-01

    Mucin 1 (MUC1) is a type I transmembrane glycoprotein abundantly expressed on nearly all epithelial tissues and overexpressed by many cancer cells. Previous studies from our lab showed that progesterone receptor (PR)B is a strong stimulator of MUC1 gene expression. It is reported that liganded peroxisome proliferator-activated receptor gamma (PPARgamma) stimulates Muc1 expression in murine trophoblast. Here, we demonstrate that although the PPARgamma ligand, rosiglitazone, stimulates the murine Muc1 promoter in HEC1A, a human uterine epithelial cell line, rosiglitazone alone, has no significant effect on basal human MUC1 promoter activity. In fact, rosiglitazone treatment antagonizes progesterone-stimulated human MUC1 promoter activity and protein expression in two human uterine epithelial cell lines and T47D human breast cancer cells. This response is antagonized by the PPARgamma antagonist, GW9662, as well as a dominant-negative form of PPARgamma, demonstrating the response is mediated by PPARgamma. Additional studies indicate that PPARgamma activation does not change PR binding to the MUC1 promoter but generally antagonizes progesterone activity by stimulating PRB degradation and inhibiting progesterone-induced PRB phosphorylation. Collectively, these studies indicate that PPARgamma activation inhibits PRB activity through both acute (phosphorylation) and long-term (PRB degradation) pathways.

  9. Potent and Specific Inhibition of Human Immunodeficiency Virus Type 1 Replication by RNA Interference

    PubMed Central

    Coburn, Glen A.; Cullen, Bryan R.

    2002-01-01

    Synthetic small interfering RNAs (siRNAs) have been shown to induce the degradation of specific mRNA targets in human cells by inducing RNA interference (RNAi). Here, we demonstrate that siRNA duplexes targeted against the essential Tat and Rev regulatory proteins encoded by human immunodeficiency virus type 1 (HIV-1) can specifically block Tat and Rev expression and function. More importantly, we show that these same siRNAs can effectively inhibit HIV-1 gene expression and replication in cell cultures, including those of human T-cell lines and primary lymphocytes. These observations demonstrate that RNAi can effectively block virus replication in human cells and raise the possibility that RNAi could provide an important innate protective response, particularly against viruses that express double-stranded RNAs as part of their replication cycle. PMID:12186906

  10. A DFT-based QSAR study on inhibition of human dihydrofolate reductase.

    PubMed

    Karabulut, Sedat; Sizochenko, Natalia; Orhan, Adnan; Leszczynski, Jerzy

    2016-11-01

    Diaminopyrimidine derivatives are frequently used as inhibitors of human dihydrofolate reductase, for example in treatment of patients whose immune system are affected by human immunodeficiency virus. Forty-seven dicyclic and tricyclic potential inhibitors of human dihydrofolate reductase were analyzed using the quantitative structure-activity analysis supported by DFT-based and DRAGON-based descriptors. The developed model yielded an RMSE deviation of 1.1 a correlation coefficient of 0.81. The prediction set was characterized by R(2)=0.60 and RMSE=3.59. Factors responsible for inhibition process were identified and discussed. The resulting model was validated via cross validation and Y-scrambling procedure. From the best model, we found several mass-related descriptors and Sanderson electronegativity-related descriptors that have the best correlations with the investigated inhibitory concentration. These descriptors reflect results from QSAR studies based on characteristics of human dihydrofolate reductase inhibitors.

  11. Metal inhibition of human alkylpurine-DNA-N-glycosylase activityin base excision repair

    SciTech Connect

    Wang, Ping; Guliaev, Anton B.; Hang, Bo

    2006-02-28

    Cadmium (Cd{sup 2+}), nickel (Ni{sup 2+}) and cobalt (Co{sup 2+}) are human and/or animal carcinogens. Zinc (Zn{sup 2+}) is not categorized as a carcinogen, and rather an essential element to humans. Metals were recently shown to inhibit DNA repair proteins that use metals for their function and/or structure. Here we report that the divalent ions Cd{sup 2+}, Ni{sup 2+}, and Zn{sup 2+} can inhibit the activity of a recombinant human N-methylpurine-DNA glycosylase (MPG) toward a deoxyoligonucleotide with ethenoadenine (var epsilonA). MPG removes a variety of toxic/mutagenic alkylated bases and does not require metal for its catalytic activity or structural integrity. At concentrations starting from 50 to 1000 {micro}M, both Cd{sup 2+} and Zn{sup 2+} showed metal-dependent inhibition of the MPG catalytic activity. Ni{sup 2+} also inhibited MPG, but to a lesser extent. Such an effect can be reversed with EDTA addition. In contrast, Co{sup 2+} and Mg{sup 2+} did not inhibit the MPG activity in the same dose range. Experiments using HeLa cell-free extracts demonstrated similar patterns of inactivation of the var epsilonA excision activity by the same metals. Binding of MPG to the substrate was not significantly affected by Cd{sup 2+}, Zn{sup 2+}, and Ni{sup 2+} at concentrations that show strong inhibition of the catalytic function, suggesting that the reduced catalytic activity is not due to altered MPG binding affinity to the substrate. Molecular dynamics (MD) simulations with Zn{sup 2+} showed that the MPG active site has a potential binding site for Zn{sup 2+}, formed by several catalytically important and conserved residues. Metal binding to such a site is expected to interfere with the catalytic mechanism of this protein. These data suggest that inhibition of MPG activity may contribute to metal genotoxicity and depressed repair of alkylation damage by metals in vivo.

  12. Gemifloxacin inhibits migration and invasion and induces mesenchymal-epithelial transition in human breast adenocarcinoma cells.

    PubMed

    Chen, Tun-Chieh; Hsu, Ya-Ling; Tsai, Yu-Chieh; Chang, Yu-Wei; Kuo, Po-Lin; Chen, Yen-Hsu

    2014-01-01

    Gemifloxacin (GMF) is a fluoroquinolone antibiotic that inhibits bacterial DNA gyrase and topoisomerase IV. The aim of this study was to investigate the anti-metastatic activities of GMF and its possible mechanisms of action, with a special focus on the induction of mesenchymal-epithelial transition (MET). The human breast adenocarcinoma cell lines MDA-MB-231 and MDA-MB-453 were used to assess the anti-metastatic activity of GMF on cell migration and invasion and in scratch wound-healing assays. The effects of GMF on the MET and its regulatory nuclear factor κB (NF-κB)/Snail pathway were assessed. The in vivo anti-metastatic effect of GMF was also evaluated in an animal model. This study demonstrated that GMF inhibited the migration and invasion of MDA-MB-231 and MDA-MB-453 cells and induced the MET. GMF suppressed the activation of NF-κB, as well as the cell migration and invasion induced by tumor necrosis factor α (TNF-α). GMF was shown to inhibit the phosphorylation of the inhibitor of κB (IκB) and the translocation of NF-κB/Snail in both cancer cell lines. This study showed that the Raf kinase inhibitor protein (RKIP), an inhibitor of IκB kinase, is upregulated after GMF treatment. Inhibition of RKIP by small hairpin RNA transfection significantly decreased the inhibitory effect of GMF on the NF-κB/Snail pathway and also inhibited cell migration and invasion. Overexpression of Snail suppressed GMF-mediated metastasis inhibition and E-cadherin upregulation. An animal model revealed that GMF effectively inhibits lipopolysaccharide-mediated metastasis in mice. This study has demonstrated that GMF might be a novel anticancer agent for the prevention and treatment of metastasis in breast cancer. GMF inhibits the migration and invasion of human breast adenocarcinoma cells. GMF induces MET by reducing NF-κB and Snail activation and by increasing RKIP levels. GMF has potential clinical implication as an anti-metastatic agent for breast cancer.

  13. Inhibition of Human Cytomegalovirus pUL89 Terminase Subunit Blocks Virus Replication and Genome Cleavage.

    PubMed

    Wang, Yan; Mao, Lili; Kankanala, Jayakanth; Wang, Zhengqiang; Geraghty, Robert J

    2017-02-01

    The human cytomegalovirus terminase complex cleaves concatemeric genomic DNA into unit lengths during genome packaging and particle assembly. This process is an attractive drug target because cleavage of concatemeric DNA is not required in mammalian cell DNA replication, indicating that drugs targeting the terminase complex could be safe and selective. One component of the human cytomegalovirus terminase complex, pUL89, provides the endonucleolytic activity for genome cleavage, and the domain responsible is reported to have an RNase H-like fold. We hypothesize that the pUL89 endonuclease activity is inhibited by known RNase H inhibitors. Using a novel enzyme-linked immunosorbent assay (ELISA) format as a screening assay, we found that a hydroxypyridonecarboxylic acid compound, previously reported to be an inhibitor of human immunodeficiency virus RNase H, inhibited pUL89 endonuclease activity at low-micromolar concentrations. Further characterization revealed that this pUL89 endonuclease inhibitor blocked human cytomegalovirus replication at a relatively late time point, similarly to other reported terminase complex inhibitors. Importantly, this inhibitor also prevented the cleavage of viral genomic DNA in infected cells. Taken together, these results substantiate our pharmacophore hypothesis and validate our ligand-based approach toward identifying novel inhibitors of pUL89 endonuclease. Human cytomegalovirus infection in individuals lacking a fully functioning immune system, such as newborns and transplant patients, can have severe and debilitating consequences. The U.S. Food and Drug Administration-approved anti-human cytomegalovirus drugs mainly target the viral polymerase, and resistance to these drugs has appeared. Therefore, anti-human cytomegalovirus drugs from novel targets are needed for use instead of, or in combination with, current polymerase inhibitors. pUL89 is a viral ATPase and endonuclease and is an attractive target for anti-human cytomegalovirus

  14. The Ba fragment of complement factor B inhibits human B lymphocyte proliferation.

    PubMed

    Ambrus, J L; Peters, M G; Fauci, A S; Brown, E J

    1990-03-01

    Normal human B lymphocyte function is finely regulated by both positive and negative signals at each stage of activation, proliferation, and differentiation. Activation signals include antigen and surface Ig cross-linking agents such as anti-mu or anti-delta. Signals inducing proliferation include IL-2, high m.w.-B cell growth factor (BCGF), and low m.w.-BCGF. IL-2 as well as IL-6 and other partially characterized B cell differentiation factors can induce terminal differentiation of proliferating B cells into Ig-secreting plasma cells. Various C components have been described to regulate B cell function including Bb that enhances proliferation, C5a that enhances Ig production, and C3a that inhibits Ig production. In our study, we examined the ability of the factor B cleavage fragment Ba to influence human B cell function. Ba did not affect the activation of resting B cells but inhibited the proliferation of activated B cells stimulated with either high m.w.-BCGF or low m.w.-BCGF. The inhibition occurred with doses of Ba as low as 1 microgram/ml (29 nM). Ba was found to bind to activated human B lymphocytes in a saturable manner with an apparent K of approximately 25 nM and an apparent Bmax of 56,000 sites/cell. A peptide made of the carboxy terminal 10 amino acids of Ba (GHGPGEQQKR), was also found to inhibit growth factor induced proliferation of activated B cells but at an ID50 of approximately 5 microM. Finally, Ba was found to inhibit the terminal differentiation of Staphylococcus aweus Cowan-activated B cells stimulated with B cell differentiation factors but not Ig secretion by the partially differentiated EBV-transformed cell line SKW.6. Thus, concentrations of Ba achievable in vivo at sites of active inflammation were found to act on human B lymphocytes by inhibiting their proliferation. This may act to limit the immune response to a specific antigenic challenge.

  15. Inhibition of casein kinase 2 prevents growth of human osteosarcoma.

    PubMed

    Takahashi, Kengo; Setoguchi, Takao; Tsuru, Arisa; Saitoh, Yoshinobu; Nagano, Satoshi; Ishidou, Yasuhiro; Maeda, Shingo; Furukawa, Tatsuhiko; Komiya, Setsuro

    2017-02-01

    High-dose chemotherapy and surgical treatment have improved the prognosis of osteosarcoma. However, more than 20% of patients with osteosarcoma still have a poor prognosis. We investigated the expression and function of casein kinase 2 (CK2) in osteosarcoma growth. We then examined the effects of CX-4945, a CK2 inhibitor, on osteosarcoma growth in vitro and in vivo to apply our findings to the clinical setting. We examined the expression of CK2α and CK2β by western blot analysis, and performed WST-1 assays using CK2α and CK2β siRNA or CX-4945. Flow cytometry and western blot analyses were performed to evaluate apoptotic cell death. Xenograft models were used to examine the effect of CX-4945 in vivo. Western blot analysis revealed upregulation of CK2α and CK2β in human osteosarcoma cell lines compared with human osteoblast cells or mesenchymal stem cells. WST assay showed that knockdown of CK2α or CK2β by siRNA inhibited the proliferation of human osteosarcoma cells. Treatment with 3 µM of CX-4945 inhibited osteosarcoma cell proliferation; however, the same concentration of CX-4945 did not affect the proliferation of human mesenchymal stem cells. Additionally, treatment with CX-4945 inhibited the proliferation of human osteosarcoma cells in a dose-dependent manner. Western blot and flow cytometry analyses showed that treatment with CX-4945 promoted apoptotic death of osteosarcoma cells. The xenograft model showed that treatment with CX-4945 significantly prevented osteosarcoma growth in vivo compared with control vehicle treatment. Our findings indicate that CK2 may be an attractive therapeutic target for treating osteosarcoma.

  16. TGF-β3 Inhibits Antibody Production by Human B Cells

    PubMed Central

    Tsuchida, Yumi; Sumitomo, Shuji; Ishigaki, Kazuyoshi; Suzuki, Akari; Kochi, Yuta; Tsuchiya, Haruka; Ota, Mineto; Komai, Toshihiko; Inoue, Mariko; Morita, Kaoru; Okamura, Tomohisa; Yamamoto, Kazuhiko; Fujio, Keishi

    2017-01-01

    TGF-β is a pleotropic cytokine involved in various biological processes. Of the three isoforms of TGF-β, TGF-β1 has long been recognized as an important inhibitory cytokine in the immune system and has been reported to inhibit B cell function in both mice and humans. Recently, it has been suggested that TGF-β3 may play an important role in the regulation of immune system in mice. Murine CD4+CD25-LAG3+ regulatory T cells suppress B cell function through the production of TGF-β3, and it has been reported that TGF-β3 is therapeutic in a mouse model of systemic lupus erythematosus. The effect of TGF-β3 on human B cells has not been reported, and we herein examined the effect of TGF-β3 on human B cells. TGF-β3 suppressed B cell survival, proliferation, differentiation into plasmablasts, and antibody secretion. Although the suppression of human B cells by TGF-β1 has long been recognized, the precise mechanism for the suppression of B cell function by TGF-β1 remains elusive; therefore, we examined the effect of TGF-β1 and β3 on pathways important in B cell activation and differentiation. TGF-β1 and TGF-β3 inhibited some of the key molecules of the cell cycle, as well as transcription factors important in B cell differentiation into antibody secreting cells such as IRF4, Blimp-1, and XBP1. TGF-β1 and β3 also inhibited B cell receptor signaling. Our results suggest that TGF-β3 modifying therapy might be therapeutic in autoimmune diseases with B cell dysregulation in humans. PMID:28052118

  17. Inhibition of recombinant human T-type calcium channels by Delta9-tetrahydrocannabinol and cannabidiol.

    PubMed

    Ross, Hamish Redmond; Napier, Ian; Connor, Mark

    2008-06-06

    Delta(9)-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most prevalent biologically active constituents of Cannabis sativa. THC is the prototypic cannabinoid CB1 receptor agonist and is psychoactive and analgesic. CBD is also analgesic, but it is not a CB1 receptor agonist. Low voltage-activated T-type calcium channels, encoded by the Ca(V)3 gene family, regulate the excitability of many cells, including neurons involved in nociceptive processing. We examined the effects of THC and CBD on human Ca(V)3 channels stably expressed in human embryonic kidney 293 cells and T-type channels in mouse sensory neurons using whole-cell, patch clamp recordings. At moderately hyperpolarized potentials, THC and CBD inhibited peak Ca(V)3.1 and Ca(V)3.2 currents with IC(50) values of approximately 1 mum but were less potent on Ca(V)3.3 channels. THC and CBD inhibited sensory neuron T-type channels by about 45% at 1 mum. However, in recordings made from a holding potential of -70 mV, 100 nm THC or CBD inhibited more than 50% of the peak Ca(V)3.1 current. THC and CBD produced a significant hyperpolarizing shift in the steady state inactivation potentials for each of the Ca(V)3 channels, which accounts for inhibition of channel currents. Additionally, THC caused a modest hyperpolarizing shift in the activation of Ca(V)3.1 and Ca(V)3.2. THC but not CBD slowed Ca(V)3.1 and Ca(V)3.2 deactivation and inactivation kinetics. Thus, THC and CBD inhibit Ca(V)3 channels at pharmacologically relevant concentrations. However, THC, but not CBD, may also increase the amount of calcium entry following T-type channel activation by stabilizing open states of the channel.

  18. Immunostimulatory DNA inhibits IL-4-dependent IgE synthesis by human B cells.

    PubMed

    Horner, A A; Widhopf, G F; Burger, J A; Takabayashi, K; Cinman, N; Ronaghy, A; Spiegelberg, H L; Raz, E

    2001-09-01

    Immunostimulatory sequence oligodeoxynucleotide (ISS-ODN) is a potent antiallergic immunomodulating agent in mice. However, few studies have addressed its antiallergic potential in human subjects. We sought to determine whether a phosphoro-thioate ISS-ODN could inhibit IL-4-dependent IgE synthesis by human B cells. Initially, nonatopic- and atopic-donor PBMCs were incubated with ISS-ODN or mutated oligodeoxynucleotide, and cytokine production and B-cell expression of IFN-gamma receptor and IL-4 receptor were measured by using ELISA and flow cytometry, respectively. In subsequent studies atopic-donor PBMCs were incubated with IL-4 alone or with ISS-ODN or mutated oligodeoxynucleotide. After 14 days, IgE production and IgM, IgG, and IgA production were determined by using ELISA. In select IgE studies cytokines were neutralized with mAbs. ISS-ODN induced IL-12, IFN-alpha, IFN-gamma, IL-10, and IL-6 production from both nonatopic- and atopic-donor PBMCs. ISS-ODN also increased IFN-gamma receptor and inhibited IL-4 receptor expression on B cells from both donor populations. Furthermore, ISS-ODN inhibited IL-4-dependent IgE production by atopic-donor PBMCs. Neutralization of IL-12, IFN-alpha, IFN-gamma, and IL-10, but not IL-6, attenuated the inhibitory activity of ISS-ODN on IgE production. In contrast to its inhibition of IgE synthesis, ISS-ODN stimulated the production of IgM, IgG, and IgA. These in vitro studies demonstrate that phos-phorothioate ISS-ODN elicits an innate immune response by PBMCs, which inhibits IL-4-dependent IgE synthesis. In addition, these results provide further support for consideration of ISS-ODN therapy for the treatment of allergic disease in clinical practice.

  19. Lovastatin inhibits TGF-beta-induced myofibroblast transdifferentiation in human tenon fibroblasts.

    PubMed

    Meyer-Ter-Vehn, Tobias; Katzenberger, Barbara; Han, Hong; Grehn, Franz; Schlunck, Günther

    2008-09-01

    The transdifferentiation of Tenon fibroblasts to myofibroblasts is a pivotal step in filtering bleb scarring. It is mediated by the cytokine TGF-beta, Rho-dependent contractility, and cell-matrix interactions in an interdependent fashion. HMG-CoA-reductase inhibitors (statins) have been shown to inhibit Rho-GTPase signaling; therefore, the authors studied the influence of lovastatin on TGF-beta-mediated myofibroblast transdifferentiation to assess the potential use of statins in wound healing modulation. Human Tenon fibroblasts were grown in culture, pretreated with lovastatin, lovastatin and mevalonate, or specific inhibitors of farnesyl transferase or geranylgeranyl transferase and were stimulated with TGF-beta1. alpha-Smooth muscle actin (alpha-SMA) and connective tissue growth factor (CTGF) transcription were assessed by real-time PCR. alpha-SMA protein expression and localization were studied by Western blot and confocal immunofluorescence microscopy. Cell contractility was determined in collagen gel contraction assays. Phosphorylation of the signaling proteins Smad-2/3 and p38 were detected by Western blot, and Smad-2/3 localization was determined by confocal immunofluorescence microscopy. Lovastatin inhibited TGF-beta-induced CTGF transcription, alpha-SMA expression and incorporation into actin stress fibers, and subsequent collagen gel contraction. These effects were reversed by mevalonate. The inhibition of geranylgeranyl transferase but not farnesyl transferase blocked TGF-beta-induced alpha-SMA expression. Lovastatin decreased TGF-beta-induced p38 activation, whereas Smad-2/3 phosphorylation and nuclear translocation were preserved. Lovastatin inhibits TGF-beta-induced myofibroblast transdifferentiation in human Tenon fibroblasts, most likely by interfering with Rho-signaling. Statins may, therefore, serve to inhibit scarring after filtering glaucoma surgery.

  20. Inhibition of Recombinant Human T-type Calcium Channels by Δ9-Tetrahydrocannabinol and Cannabidiol*

    PubMed Central

    Ross, Hamish Redmond; Napier, Ian; Connor, Mark

    2008-01-01

    Δ9-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most prevalent biologically active constituents of Cannabis sativa. THC is the prototypic cannabinoid CB1 receptor agonist and is psychoactive and analgesic. CBD is also analgesic, but it is not a CB1 receptor agonist. Low voltage-activated T-type calcium channels, encoded by the CaV3 gene family, regulate the excitability of many cells, including neurons involved in nociceptive processing. We examined the effects of THC and CBD on human CaV3 channels stably expressed in human embryonic kidney 293 cells and T-type channels in mouse sensory neurons using whole-cell, patch clamp recordings. At moderately hyperpolarized potentials, THC and CBD inhibited peak CaV3.1 and CaV3.2 currents with IC50 values of ∼1 μm but were less potent on CaV3.3 channels. THC and CBD inhibited sensory neuron T-type channels by about 45% at 1 μm. However, in recordings made from a holding potential of -70 mV, 100 nm THC or CBD inhibited more than 50% of the peak CaV3.1 current. THC and CBD produced a significant hyperpolarizing shift in the steady state inactivation potentials for each of the CaV3 channels, which accounts for inhibition of channel currents. Additionally, THC caused a modest hyperpolarizing shift in the activation of CaV3.1 and CaV3.2. THC but not CBD slowed CaV3.1 and CaV3.2 deactivation and inactivation kinetics. Thus, THC and CBD inhibit CaV3 channels at pharmacologically relevant concentrations. However, THC, but not CBD, may also increase the amount of calcium entry following T-type channel activation by stabilizing open states of the channel. PMID:18390906

  1. Inhibition of replicon initiation in human cells following stabilization of topoisomerase-DNA cleavable complexes.

    PubMed Central

    Kaufmann, W K; Boyer, J C; Estabrooks, L L; Wilson, S J

    1991-01-01

    Diploid human fibroblast strains were treated for 10 min with inhibitors of type I and type II DNA topoisomerases, and after removal of the inhibitors, the rate of initiation of DNA synthesis at replicon origins was determined. By alkaline elution chromatography, 4'-(9-acridinylamino)methanesulfon-m-anisidide (amsacrine), an inhibitor of DNA topoisomerase II, was shown to produce DNA strand breaks. These strand breaks are thought to reflect drug-induced stabilization of topoisomerase-DNA cleavable complexes. Removal of the drug led to a rapid resealing of the strand breaks by dissociation of the complexes. Velocity sedimentation analysis was used to quantify the effects of amsacrine treatment on DNA replication. It was demonstrated that transient exposure to low concentrations of amsacrine inhibited replicon initiation but did not substantially affect DNA chainelongation within operating replicons. Maximal inhibition of replicon initiation occurred 20 to 30 min after drug treatment, and the initiation rate recovered 30 to 90 min later. Ataxia telangiectasia cells displayed normal levels of amsacrine-induced DNA strand breaks during stabilization of cleavable complexes but failed to downregulate replicon initiation after exposure to the topoisomerase inhibitor. Thus, inhibition of replicon initiation in response to DNA damage appears to be an active process which requires a gene product which is defective or missing in ataxia telangiectasia cells. In normal human fibroblasts, the inhibition of DNA topoisomerase I by camptothecin produced reversible DNA strand breaks. Transient exposure to this drug also inhibited replicon initiation. These results suggest that the cellular response pathway which downregulates replicon initiation following genotoxic damage may respond to perturbations of chromatin structure which accompany stabilization of topoisomerase-DNA cleavable complexes. PMID:1646393

  2. An evaluation of the inhibition of human butyrylcholinesterase and acetylcholinesterase by the organophosphate chlorpyrifos oxon

    SciTech Connect

    Shenouda, Josephine; Green, Paula; Sultatos, Lester

    2009-12-01

    Acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) are enzymes that belong to the superfamily of alpha/beta-hydrolase fold proteins. While they share many characteristics, they also possess many important differences. For example, whereas they have about 54% amino acid sequence identity, the active site gorge of acetylcholinesterase is considerably smaller than that of butyrylcholinesterase. Moreover, both have been shown to display simple and complex kinetic mechanisms, depending on the particular substrate examined, the substrate concentration, and incubation conditions. In the current study, incubation of butyrylthiocholine in a concentration range of 0.005-3.0 mM, with 317 pM human butyrylcholinesterase in vitro, resulted in rates of production of thiocholine that were accurately described by simple Michaelis-Menten kinetics, with a K{sub m} of 0.10 mM. Similarly, the inhibition of butyrylcholinesterase in vitro by the organophosphate chlorpyrifos oxon was described by simple Michaelis-Menten kinetics, with a k{sub i} of 3048 nM{sup -1} h{sup -1}, and a K{sub D} of 2.02 nM. In contrast to inhibition of butyrylcholinesterase, inhibition of human acetylcholinesterase by chlorpyrifos oxon in vitro followed concentration-dependent inhibition kinetics, with the k{sub i} increasing as the inhibitor concentration decreased. Chlorpyrifos oxon concentrations of 10 and 0.3 nM gave k{sub i}s of 1.2 and 19.3 nM{sup -1} h{sup -1}, respectively. Although the mechanism of concentration-dependent inhibition kinetics is not known, the much smaller, more restrictive active site gorge of acetylcholinesterase almost certainly plays a role. Similarly, the much larger active site gorge of butyrylcholinesterase likely contributes to its much greater reactivity towards chlorpyrifos oxon, compared to acetylcholinesterase.

  3. β-catenin knockdown inhibits the proliferation of human glioma cells in vitro and in vivo

    PubMed Central

    WANG, ZHONG; CHEN, QIANXUE

    2016-01-01

    β-catenin is a crucial oncogene that is capable of regulating cancer progression. The aim of the present study was to clarify whether β-catenin was associated with the proliferation and progress of glioma. In order to knockdown the expression of β-catenin in human U251 glioma cells, three pairs of small interfering (si)RNA were designed and synthesized and the most effective siRNA was selected and used for silencing the endogenous β-catenin, which was detected by western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Proliferation was subsequently detected using a methylthiazolyl-tetrazolium bromide assay and the results demonstrated that knockdown of β-catenin significantly inhibited the proliferation of U251 cells in a time- and dose-dependent manner (P<0.01). Cell apoptosis rate was analyzed using flow cytometry and Annexin V-fluorescein isothiocyanate/propidium iodide staining demonstrated that β-catenin siRNA significantly increased the apoptosis of U251 cells (P<0.01). Furthermore, the results of an in vitro scratch assay demonstrated that β-catenin silencing suppressed the proliferation of U251 cells, as compared with the control group (P<0.01). In vivo, β-catenin expression levels in U251 cells were significantly inhibited (P<0.01) following β-catenin short hairpin (sh)RNA lentiviral-vector transfection, as detected by western blot analysis and RT-qPCR. Tumorigenicity experiments demonstrated that β-catenin inhibition significantly increased the survival rate of nude mice. The results of the present study demonstrated that knockdown of β-catenin expression significantly inhibited the progression of human glioma cancer cells, in vitro and in vivo; thus suggesting that β-catenin silencing may be a novel therapy for the treatment of human glioma. PMID:26998037

  4. Cyclooxygenase-2 Inhibition Limits Angiotensin II-Induced DNA Oxidation and Protein Nitration in Humans

    PubMed Central

    Pialoux, Vincent; Poulin, Marc J.; Hemmelgarn, Brenda R.; Muruve, Daniel A.; Chirico, Erica N.; Faes, Camille; Sola, Darlene Y.; Ahmed, Sofia B.

    2017-01-01

    Compared to other cyclooxygenase-2 inhibitors, celecoxib is associated with a lower cardiovascular risk, though the mechanism remains unclear. Angiotensin II is an important mediator of oxidative stress in the pathophysiology of vascular disease. Cyclooxygenase-2 may modify the effects of angiotensin II though this has never been studied in humans. The purpose of the study was to test the effects of selective cyclooxygenase-2 inhibition on plasma measures of oxidative stress, the vasoconstrictor endothelin-1, and nitric oxide metabolites, both at baseline and in respose to Angiotensin II challenge in healthy humans. Measures of 8-hydroxydeoxyguanosine, advanced oxidation protein products, nitrotyrosine, endothelin-1, and nitric oxide metabolites were assessed from plasma samples drawn at baseline and in response to graded angiotensin II infusion (3 ng/kg/min × 30 min, 6 ng/kg/min × 30 min) before and after 14 days of cyclooxygenase-2 inhibition in 14 healthy subjects (eight male, six female) in high salt balance, a state of maximal renin angiotensin system suppression. Angiotensin II infusion significantly increased plasma oxidative stress compared to baseline (8-hydroxydeoxyguanosine; +17%; advanced oxidation protein products; +16%), nitrotyrosine (+76%). Furthermore, levels of endothelin-1 levels were significantly increased (+115%) and nitric oxide metabolites were significantly decreased (−20%). Cycloxygenase-2 inhibition significantly limited the increase in 8-hydroxydeoxyguanosine, nitrotyrosine and the decrease in nitric oxide metabolites induced by angiotensin II infusion, though no changes in advanced oxidation protein products and endothelin-1 concentrations were observed. Cyclooxygenase-2 inhibition with celecoxib partially limited the angiotensin II-mediated increases in markers of oxidative stress in humans, offering a potential physiological pathway for the improved cardiovascular risk profile of this drug. PMID:28344559

  5. Baicalein inhibits the migration and invasive properties of human hepatoma cells

    SciTech Connect

    Chiu, Yung-Wei; Lin, Tseng-Hsi; Huang, Wen-Shih; Teng, Chun-Yuh; Liou, Yi-Sheng; Kuo, Wu-Hsien; Lin, Wea-Lung; Huang, Hai-I; Tung, Jai-Nien; Huang, Chih-Yang; Liu, Jer-Yuh; Wang, Wen-Hung; Hwang, Jin-Ming

    2011-09-15

    Flavonoids have been demonstrated to exert health benefits in humans. We investigated whether the flavonoid baicalein would inhibit the adhesion, migration, invasion, and growth of human hepatoma cell lines, and we also investigated its mechanism of action. The separate effects of baicalein and baicalin on the viability of HA22T/VGH and SK-Hep1 cells were investigated for 24 h. To evaluate their invasive properties, cells were incubated on matrigel-coated transwell membranes in the presence or absence of baicalein. We examined the effect of baicalein on the adhesion of cells, on the activation of matrix metalloproteinases (MMPs), protein kinase C (PKC), and p38 mitogen-activated protein kinase (MAPK), and on tumor growth in vivo. We observed that baicalein suppresses hepatoma cell growth by 55%, baicalein-treated cells showed lower levels of migration than untreated cells, and cell invasion was significantly reduced to 28%. Incubation of hepatoma cells with baicalein also significantly inhibited cell adhesion to matrigel, collagen I, and gelatin-coated substrate. Baicalein also decreased the gelatinolytic activities of the matrix metalloproteinases MMP-2, MMP-9, and uPA, decreased p50 and p65 nuclear translocation, and decreased phosphorylated I-kappa-B (IKB)-{beta}. In addition, baicalein reduced the phosphorylation levels of PKC{alpha} and p38 proteins, which regulate invasion in poorly differentiated hepatoma cells. Finally, when SK-Hep1 cells were grown as xenografts in nude mice, intraperitoneal (i.p.) injection of baicalein induced a significant dose-dependent decrease in tumor growth. These results demonstrate the anticancer properties of baicalein, which include the inhibition of adhesion, invasion, migration, and proliferation of human hepatoma cells in vivo. - Highlight: > Baicalein inhibits several essential steps in the onset of metastasis.

  6. Inhibition of Human Neutrophil Responses by the Essential Oil of Artemisia kotuchovii and Its Constituents.

    PubMed

    Schepetkin, Igor A; Kushnarenko, Svetlana V; Özek, Gulmira; Kirpotina, Liliya N; Utegenova, Gulzhakhan A; Kotukhov, Yuriy A; Danilova, Alevtina N; Özek, Temel; Başer, K Hüsnü Can; Quinn, Mark T

    2015-05-27

    Essential oils were obtained by hydrodistillation of the flowers+leaves and stems of Artemisia kotuchovii Kupr. (AKEO(f+l) and AKEO(stm), respectively) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The primary components of the oils were estragole, (E)- and (Z)-β-ocimenes, methyleugenol, limonene, spathulenol, β-pinene, myrcene, and (E)-methyl cinnamate. Seventy-four constituents were present at concentrations from 0.1 to 1.0%, and 34 compounds were identified in trace (<0.1%) amounts in one or both plant components. Screening of the essential oils for biological activity showed that AKEO(stm), but not AKEOf+l, inhibited N-formyl-Met-Leu-Phe (fMLF)-stimulated Ca(2+) flux and chemotaxis and phorbol-12-myristate-13-acetate (PMA)-induced reactive oxygen species (ROS) production in human neutrophils. Selected pure constituents, representing >96% of the AKEO(stm) composition, were also tested in human neutrophils and HL-60 cells transfected with N-formyl peptide receptor 1 (FPR1). One component, 6-methyl-3,5-heptadien-2-one (MHDO), inhibited fMLF- and interleukin 8 (IL-8)-stimulated Ca(2+) flux, fMLF-induced chemotaxis, and PMA-induced ROS production in human neutrophils. MHDO also inhibited fMLF-induced Ca(2+) flux in FPR1-HL60 cells. These results suggest that MHDO may be effective in modulating some innate immune responses, possibly by inhibition of neutrophil migration and ROS production.

  7. Inhibition of Human Neutrophil Responses by Essential Oil of Artemisia kotuchovii and Its Constituents

    PubMed Central

    Schepetkin, Igor A.; Kushnarenko, Svetlana V.; Özek, Gulmira; Kirpotina, Liliya N.; Utegenova, Gulzhakhan A.; Kotukhov, Yuriy A.; Danilova, Alevtina N.; Özek, Temel; Başer, K. Hüsnü Can; Quinn, Mark T.

    2015-01-01

    Essential oils were obtained by hydrodistillation of the flowers+leaves and stems of Artemisia kotuchovii Kupr. (AKEOf+l and AKEOstm, respectively) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The primary components of the oils were estragole, (E)- and (Z)-β-ocimenes, methyl eugenol, limonene, spathulenol, β-pinene, myrcene, and (E)-methyl cinnamate. Seventy four constituents were present at concentrations from 0.1 to 1.0%, and 34 compounds were identified in trace (<0.1%) amounts in one or both plant components. Screening of the essential oils for biological activity showed that AKEOstm, but not AKEOf+l, inhibited N-formyl-Met-Leu-Phe (fMLF)-stimulated Ca2+ flux and chemotaxis and phorbol-12-myristate-13-acetate (PMA)-induced reactive oxygen species (ROS) production in human neutrophils. Selected pure constituents, representing >96% of the AKEOstm composition, were also tested in human neutrophils and HL-60 cells transfected with N-formyl peptide receptor 1 (FPR1). We found that one component, 6-methyl-3,5-heptadien-2-one (MHDO), inhibited fMLF- and interleukin 8 (IL-8)-stimulated Ca2+ flux, fMLF-induced chemotaxis, and PMA-induced ROS production in human neutrophils. MHDO also inhibited fMLF-induced Ca2+ flux in FPR1-HL60 cells. These results suggest that MHDO may be effective in modulating some innate immune responses, possibly by an inhibition of neutrophil migration and ROS production. PMID:25959257

  8. FRMD6 inhibits human glioblastoma growth and progression by negatively regulating activity of receptor tyrosine kinases

    PubMed Central

    Xu, Yin; Wang, Kaiqiang; Yu, Qin

    2016-01-01

    FRMD6 is an Ezrin/Radixin/Moesin (ERM) family protein and a human homologue of Drosophila expanded (ex). Ex functions in parallel of Drosophila merlin at upstream of the Hippo signaling pathway that controls proliferation, apoptosis, tissue regeneration, and tumorigenesis. Even though the core kinase cascade (MST1/2-Lats1/2-YAP/TAZ) of the Hippo pathway has been well established, its upstream regulators are not well understood. Merlin promotes activation of the Hippo pathway. However, the effect of FRMD6 on the Hippo pathway is controversial. Little is known about how FRMD6 functions and the potential role of FRMD in gliomagenesis and glioblastoma (GBM) progression. We demonstrate for the first time that FRMD6 is down-regulated in human GBM cells and tissues and that increased FRMD6 expression inhibits whereas FRMD6 knockdown promotes GBM cell proliferation/invasion in vitro and GBM growth/progression in vivo. Furthermore, we demonstrate that unlike increased expression of merlin, which enhances the stress induced activation of the Hippo pathway, increased FRMD6 expression displays little effect on the pathway. In contrast, we show that FRMD6 inhibits activation of a couple of receptor tyrosine kinases (RTKs) including c-Met and PDGFR and their downstream Erk and AKT kinases. Moreover, we show that expression of constitutively active c-Met, the TPR-Met fusion protein, largely reverses the anti-GBM effect of FRMD6 in vivo, suggesting that FRMD6 functions at least partially through inhibiting activity of RTKs especially c-Met. These results establish a novel function of FRMD6 in inhibiting human GBM growth and progression and uncover a novel mechanism by which FRMD6 exerts its anti-GBM activity. PMID:27661120

  9. Protein disulfide isomerase inhibition blocks thrombin generation in humans by interfering with platelet factor V activation

    PubMed Central

    Stopa, Jack D.; Neuberg, Donna; Puligandla, Maneka; Furie, Bruce; Zwicker, Jeffrey I.

    2017-01-01

    BACKGROUND: Protein disulfide isomerase (PDI) is required for thrombus formation. We previously demonstrated that glycosylated quercetin flavonoids such as isoquercetin inhibit PDI activity and thrombus formation in animal models, but whether extracellular PDI represents a viable anticoagulant target in humans and how its inhibition affects blood coagulation remain unknown. METHODS: We evaluated effects of oral administration of isoquercetin on platelet-dependent thrombin generation in healthy subjects and patients with persistently elevated anti-phospholipid antibodies. RESULTS: Following oral administration of 1,000 mg isoquercetin to healthy adults, the measured peak plasma quercetin concentration (9.2 μM) exceeded its IC50 for inhibition of PDI by isoquercetin in vitro (2.5 ± 0.4 μM). Platelet-dependent thrombin generation decreased by 51% in the healthy volunteers compared with baseline (P = 0.0004) and by 64% in the anti-phospholipid antibody cohort (P = 0.015) following isoquercetin ingestion. To understand how PDI affects thrombin generation, we evaluated substrates of PDI identified using an unbiased mechanistic-based substrate trapping approach. These studies identified platelet factor V as a PDI substrate. Isoquercetin blocked both platelet factor Va and thrombin generation with an IC50 of ~5 μM. Inhibition of PDI by isoquercetin ingestion resulted in a 53% decrease in the generation of platelet factor Va (P = 0.001). Isoquercetin-mediated inhibition was reversed with addition of exogenous factor Va. CONCLUSION: These studies show that oral administration of isoquercetin inhibits PDI activity in plasma and diminishes platelet-dependent thrombin generation predominantly by blocking the generation of platelet factor Va. These pharmacodynamic and mechanistic observations represent an important step in the development of a novel class of antithrombotic agents targeting PDI. TRIAL REGISTRATION: Clinicaltrials.gov (NCT01722669) FUNDING: National Heart

  10. Inhibition of human erythroid colony-forming units by tumor necrosis factor requires beta interferon.

    PubMed Central

    Means, R T; Krantz, S B

    1993-01-01

    We have previously reported that inhibition of human CFU-erythroid (E) colony formation by tumor necrosis factor (TNF) is an indirect effect mediated by a soluble factor released from a fraction of marrow accessory cells which are predominantly stromal elements (Means, R. T., Jr., E. N. Dessypris, and S. B. Krantz. 1990. J. Clin. Invest. 86:538-541). Further studies reported here identify a mediator of this effect. The inhibitory effect of recombinant TNF on marrow CFU-E is ablated by neutralizing antibodies to human beta IFN, but not by antibodies to gamma IFN or IL-1. Anti-beta IFN also neutralizes the inhibitory effect of conditioned medium prepared from marrow cells exposed to TNF. Human beta IFN inhibits colony formation by unpurified marrow CFU-E as well as highly purified CFU-E generated from peripheral blood progenitors, and limiting dilution analysis shows that this is a direct inhibitory effect. TNF has been implicated in the pathogenesis of the anemia of chronic diseases since blood TNF levels are elevated in many patients with this syndrome, and since exposure to TNF produces a similar anemia in either humans or mice. The present study demonstrates that beta IFN is a required mediator of this inhibitory effect on erythropoiesis. PMID:8432849

  11. Fully Human Antagonistic Antibodies against CCR4 Potently Inhibit Cell Signaling and Chemotaxis

    PubMed Central

    Géraudie, Solène; Scheffler, Ulrike; Griep, Remko A.; Reiersen, Herald; Duncan, Alexander R.; Kiprijanov, Sergej M.

    2014-01-01

    Background CC chemokine receptor 4 (CCR4) represents a potentially important target for cancer immunotherapy due to its expression on tumor infiltrating immune cells including regulatory T cells (Tregs) and on tumor cells in several cancer types and its role in metastasis. Methodology Using phage display, human antibody library, affinity maturation and a cell-based antibody selection strategy, the antibody variants against human CCR4 were generated. These antibodies effectively competed with ligand binding, were able to block ligand-induced signaling and cell migration, and demonstrated efficient killing of CCR4-positive tumor cells via ADCC and phagocytosis. In a mouse model of human T-cell lymphoma, significant survival benefit was demonstrated for animals treated with the newly selected anti-CCR4 antibodies. Significance For the first time, successful generation of anti- G-protein coupled chemokine receptor (GPCR) antibodies using human non-immune library and phage display on GPCR-expressing cells was demonstrated. The generated anti-CCR4 antibodies possess a dual mode of action (inhibition of ligand-induced signaling and antibody-directed tumor cell killing). The data demonstrate that the anti-tumor activity in vivo is mediated, at least in part, through Fc-receptor dependent effector mechanisms, such as ADCC and phagocytosis. Anti-CC chemokine receptor 4 antibodies inhibiting receptor signaling have potential as immunomodulatory antibodies for cancer. PMID:25080123

  12. Human adipose tissue-derived mesenchymal stem cells inhibit melanoma growth in vitro and in vivo.

    PubMed

    Ahn, Jin-Ok; Coh, Ye-Rin; Lee, Hee-Woo; Shin, Il-Seob; Kang, Sung-Keun; Youn, Hwa-Young

    2015-01-01

    The effects of adipose tissue-derived mesenchymal stem cells (AT-MSCs) on the growth of human malignancies, including melanoma, are controversial and the underlying mechanisms are not yet-well understood. The aim of the present study was to investigate the in vitro and in vivo anti-tumor effects of human AT-MSCs on human melanoma. The inhibitory effect of AT-MSC-conditioned medium (AT-MSC-CM) on the growth of A375SM and A375P (human melanoma) cells was evaluated using a cell viability assay. Cell-cycle arrest and apoptosis in melanoma cells were investigated by flow cytometry and western blot analysis. To evaluate the in vivo anti-tumor effect of AT-MSCs, CM-DiI-labeled AT-MSCs were circumtumorally injected in tumor-bearing athymic mice and tumor size was measured. AT-MSC-CM inhibited melanoma growth by altering cell-cycle distribution and inducing apoptosis in vitro. AT-MSCs suppressed tumor growth in tumor-bearing athymic mice and fluorescence analysis showed that AT-MSCs migrated efficiently to tumor tissues. AT-MSCs inhibit the growth of melanoma suggesting promise as a novel therapeutic agent for melanoma. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  13. Lycobetaine acts as a selective topoisomerase IIβ poison and inhibits the growth of human tumour cells

    PubMed Central

    Barthelmes, H U; Niederberger, E; Roth, T; Schulte, K; Tang, W C; Boege, F; Fiebig, H-H; Eisenbrand, G; Marko, D

    2001-01-01

    The phenanthridine alkaloid lycobetaine is a minor constituent of Amaryllidaceae. Inhibition of cell growth was studied in the clonogenic assay on 21 human tumour xenografts (mean IC 50 = 0.8 μM). The growth of human leukaemia cell lines was also potently inhibited (mean IC 50 = 1.3 μM). Athymic nude mice, carrying s.c. implanted human gastric tumour xenograft GXF251, were treated i.p. with lycobetaine for 4 weeks, resulting in a marked tumour growth delay. Lycobetaine was found to act as a specific topoisomerase IIβ poison. In the presence of calf thymus DNA, pure recombinant human topoisomerase IIβ protein was selectively depleted from SDS-gels, whereas no depletion of topoisomerase IIα protein was observed. In A431 cells immunoband-depletion of topoisomerase IIβ was induced, suggesting stabilization of the covalent catalytic DNA-intermediate in living cells. It is reasonable to assume that this mechanism will cause or at least contribute significantly to the antitumour activity. © 2001 Cancer Research Campaign   http://www.bjcancer.com PMID:11720449

  14. Arctigenin from Arctium lappa inhibits interleukin-2 and interferon gene expression in primary human T lymphocytes

    PubMed Central

    2011-01-01

    Background Arctium lappa (Niubang), a Chinese herbal medicine, is used to treat tissue inflammation. This study investigates the effects of arctigenin (AC), isolated from A. lappa, on anti-CD3/CD28 Ab-stimulated cell proliferation and cytokine gene expression in primary human T lymphocytes. Methods Cell proliferation was determined with enzyme immunoassays and the tritiated thymidine uptake method. Cytokine production and gene expression were analyzed with reverse transcription-polymerase chain reaction. Results AC inhibited primary human T lymphocytes proliferation activated by anti-CD3/CD28 Ab. Cell viability test indicated that the inhibitory effects of AC on primary human T lymphocyte proliferation were not due to direct cytotoxicity. AC suppressed interleukin-2 (IL-2) and interferon-γ (IFN-γ) production in a concentration-dependent manner. Furthermore, AC decreased the IL-2 and IFN-γ gene expression in primary human T lymphocytes induced by anti-CD3/CD28 Ab. Reporter gene analyses revealed that AC decreased NF-AT-mediated reporter gene expression. Conclusion AC inhibited T lymphocyte proliferation and decreased the gene expression of IL-2, IFN-γ and NF-AT. PMID:21435270

  15. Arctigenin from Arctium lappa inhibits interleukin-2 and interferon gene expression in primary human T lymphocytes.

    PubMed

    Tsai, Wei-Jern; Chang, Chu-Ting; Wang, Guei-Jane; Lee, Tzong-Huei; Chang, Shwu-Fen; Lu, Shao-Chun; Kuo, Yuh-Chi

    2011-03-25

    Arctium lappa (Niubang), a Chinese herbal medicine, is used to treat tissue inflammation. This study investigates the effects of arctigenin (AC), isolated from A. lappa, on anti-CD3/CD28 Ab-stimulated cell proliferation and cytokine gene expression in primary human T lymphocytes. Cell proliferation was determined with enzyme immunoassays and the tritiated thymidine uptake method. Cytokine production and gene expression were analyzed with reverse transcription-polymerase chain reaction. AC inhibited primary human T lymphocytes proliferation activated by anti-CD3/CD28 Ab. Cell viability test indicated that the inhibitory effects of AC on primary human T lymphocyte proliferation were not due to direct cytotoxicity. AC suppressed interleukin-2 (IL-2) and interferon-γ (IFN-γ) production in a concentration-dependent manner. Furthermore, AC decreased the IL-2 and IFN-γ gene expression in primary human T lymphocytes induced by anti-CD3/CD28 Ab. Reporter gene analyses revealed that AC decreased NF-AT-mediated reporter gene expression. AC inhibited T lymphocyte proliferation and decreased the gene expression of IL-2, IFN-γ and NF-AT.

  16. Inhibition of human arterial smooth muscle cell growth by human monocyte/macrophages: a co-culture study.

    PubMed

    Proudfoot, D; Fitzsimmons, C; Torzewski, J; Bowyer, D E

    1999-07-01

    Monocyte/macrophages produce a variety of substances which may influence the function of smooth muscle cells (SMC). During atherogenesis, macrophages are thought to modulate SMC migration, proliferation and synthesis of extracellular matrix. Such modulation is the balance between stimulatory and inhibitory influences. Thus, for example, our earlier studies have shown that macrophages not only secrete mitogens, but also produce small molecular weight inhibitors of SMC proliferation. In the present study, we have used a co-culture system in which human monocyte/macrophages were separated from human arterial SMC (hSMC) by a filter with the optional addition of a 12 kDa cut-off dialysis membrane, in order to assess their effect on hSMC growth. We have found that human peripheral blood-derived monocytes produced a substance of < 12 kDa that inhibited hSMC growth in the co-culture system. The monocyte-derived factor causing this effect was completely blocked by indomethacin, indicating that growth-inhibitory factors produced by the monocytes were cyclooxygenase products. We have shown that PGE1 and PGE2 inhibit hSMC growth, making them likely candidates for the effector molecules released from monocytes in our co-culture system.

  17. Honokiol Inhibits DNA Polymerases β and λ and Increases Bleomycin Sensitivity of Human Cancer Cells.

    PubMed

    Gowda, A S Prakasha; Suo, Zucai; Spratt, Thomas E

    2017-02-20

    A major concept to sensitize cancer cells to DNA damaging agents is by inhibiting proteins in the DNA repair pathways. X-family DNA polymerases play critical roles in both base excision repair (BER) and nonhomologous end joining (NHEJ). In this study, we examined the effectiveness of honokiol to inhibit human DNA polymerase β (pol β), which is involved in BER, and DNA polymerase λ (pol λ), which is involved in NHEJ. Kinetic analysis with purified polymerases showed that honokiol inhibited DNA polymerase activity. The inhibition mode for the polymerases was a mixed-function noncompetitive inhibition with respect to the substrate, dCTP. The X-family polymerases, pol β and pol λ, were slightly more sensitive to inhibition by honokiol based on the Ki value of 4.0 μM for pol β, and 8.3 μM for pol λ, while the Ki values for pol η and Kf were 20 and 26 μM, respectively. Next we extended our studies to determine the effect of honokiol on the cytotoxicity of bleomycin and temozolomide in human cancer cell lines A549, MCF7, PANC-1, UACC903, and normal blood lymphocytes (GM12878). Bleomycin causes both single strand DNA damage that is repaired by BER and double strand breaks that are repaired by NHEJ, while temozolomide causes methylation damage repaired by BER and O(6)-alkylguanine-DNA alkyltransferase. The greatest effects were found with the honokiol and bleomycin combination in MCF7, PANC-1, and UACC903 cells, in which the EC50 values were decreased 10-fold. The temozolomide and honokiol combination was less effective; the EC50 values decreased three-fold due to the combination. It is hypothesized that the greater effect of honokiol on bleomycin is due to inhibition of the repair of the single strand and double strand damage. The synergistic activity shown by the combination of bleomycin and honokiol suggests that they can be used as combination therapy for treatment of cancer, which will decrease the therapeutic dosage and side effects of bleomycin.

  18. Selective growth inhibition of human malignant melanoma cells by syringic acid-derived proteasome inhibitors

    PubMed Central

    2013-01-01

    Background It has been shown that proteasome inhibition leads to growth arrest in the G1 phase of the cell cycle and/or induction of apoptosis. However, it was found that some of these inhibitors do not induce apoptosis in several human normal cell lines. This selective activity makes proteasome inhibition a promising target for new generation of anticancer drugs. Clinical validation of the proteasome, as a therapeutic target in oncology, has been provided by the dipeptide boronic acid derivative; bortezomib. Bortezomib has proven to be effective as a single agent in multiple myeloma and some forms of non-Hodgkin’s lymphoma. Syringic acid (4-hydroxy-3,5-dimethoxybenzoic acid, 1), a known phenolic acid, was isolated from the methanol extract of Tamarix aucheriana and was shown to possess proteasome inhibitory activity. Methods Using Surflex-Dock program interfaced with SYBYL, the docking affinities of syringic acid and its proposed derivatives to 20S proteasome were studied. Several derivatives were virtually proposed, however, five derivatives: benzyl 4-hydroxy-3,5-dimethoxybenzoate (2), benzyl 4-(benzyloxy)-3,5-dimethoxybenzoate (3), 3'-methoxybenzyl 3,5-dimethoxy-4-(3'-methoxybenzyloxy)benzoate (4), 3'-methoxybenzyl 4-hydroxy-3,5-dimethoxybenzoate (5) and 3',5'-dimethoxybenzyl 4-hydroxy-3,5-dimethoxybenzoate (6), were selected based on high docking scores, synthesized, and tested for their anti-mitogenic activity against human colorectal, breast and malignant melanoma cells as well as normal human fibroblast cells. Results Derivatives 2, 5, and 6 showed selective dose-dependent anti-mitogenic effect against human malignant melanoma cell lines HTB66 and HTB68 with minimal cytotoxicity on colorectal and breast cancer cells as well as normal human fibroblast cells. Derivatives 2, 5 and 6 significantly (p ≤ 0.0001) inhibited the various proteasomal chymotrypsin, PGPH, and trypsin like activities. They growth arrested the growth of HTB66 cells at G1 and G2

  19. Salidroside inhibits migration and invasion of human fibrosarcoma HT1080 cells.

    PubMed

    Sun, Chao; Wang, Zhenhua; Zheng, Qiusheng; Zhang, Hong

    2012-02-15

    Oxidative stress plays an important role in tumorigenesis and metastasis. Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Here we investigated the inhibitory effects of salidroside on tumor metastasis in human fibrosarcoma HT1080 cells in vitro. The results indicated that salidroside significantly reduced wound closure areas of HT1080 cells, inhibited HT1080 cells invasion into Matrigel-coated membranes, suppressed matrix metalloproteinases (MMP-2 and MMP-9) activity, and increased tissue inhibitor of metalloproteinase-2 (TIMP-2) expression in a dose-dependent manner in HT1080 cells. Salidroside treatment upregulated the E-cadherin expression, while downregulated the expression of β1-integrin. As an antioxidant, salidroside inhibited the intracellular reactive oxygen species (ROS) formation in a dose-dependent manner. The results also showed that salidroside could inhibit the activation of protein kinase C (PKC) and the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) in a dose-dependent manner. In conclusion, these results suggest that salidroside inhibits tumor cells metastasis, which may due to its interfere in the intracellular excess ROS thereby down-regulated the ROS-PKC-ERK1/2 signaling pathway. Copyright © 2011 Elsevier GmbH. All rights reserved.

  20. Caspase-8 inhibition represses initial human monocyte activation in septic shock model

    PubMed Central

    Oliva-Martin, Maria Jose; Sanchez-Abarca, Luis Ignacio; Rodhe, Johanna; Carrillo-Jimenez, Alejandro; Vlachos, Pinelopi; Herrera, Antonio Jose; Garcia-Quintanilla, Albert; Caballero-Velazquez, Teresa; Perez-Simon, Jose Antonio; Joseph, Bertrand; Venero, Jose Luis

    2016-01-01

    In septic patients, the onset of septic shock occurs due to the over-activation of monocytes. We tested the therapeutic potential of directly targeting innate immune cell activation to limit the cytokine storm and downstream phases. We initially investigated whether caspase-8 could be an appropriate target given it has recently been shown to be involved in microglial activation. We found that LPS caused a mild increase in caspase-8 activity and that the caspase-8 inhibitor IETD-fmk partially decreased monocyte activation. Furthermore, caspase-8 inhibition induced necroptotic cell death of activated monocytes. Despite inducing necroptosis, caspase-8 inhibition reduced LPS-induced expression and release of IL-1β and IL-10. Thus, blocking monocyte activation has positive effects on both the pro and anti-inflammatory phases of septic shock. We also found that in primary mouse monocytes, caspase-8 inhibition did not reduce LPS-induced activation or induce necroptosis. On the other hand, broad caspase inhibitors, which have already been shown to improve survival in mouse models of sepsis, achieved both. Thus, given that monocyte activation can be regulated in humans via the inhibition of a single caspase, we propose that the therapeutic use of caspase-8 inhibitors could represent a more selective alternative that blocks both phases of septic shock at the source. PMID:27250033

  1. Mechanism of inhibition of human neutrophil activation by the allergic mediator release inhibitor, CI-922

    SciTech Connect

    Hoffman, M.D.; Wright, C.D.

    1986-03-05

    The allergic mediator release inhibitor CI-922 (3,7-dimethoxy-4-phenyl-N-1H-tetrazol-5-yl-4H-furo(3,2-b)indole-2-carboxamide) is a potent inhibitor of human neutrophil (PMN) respiratory and secretory responses in vitro. At concentrations from 1 to 100 micromolar, CI-922 inhibits activation of PMNs by agents which stimulate phospholipase C-dependent phosphoinositide hydrolysis to generate the second messengers inositol 1,4,5 trisphosphate and diacylglycerol, including: the plasma membrane receptor-specific ligands fMet-Leu-Phe and C5a; concanavalin A; and the guanine nucleotide regulatory protein-specific stimulus GTPgammaS. In contrast, CI-922 does not inhibit PMN responses to protein kinase C-specific stimuli such as phorbol myristate acetate (PMA) or sn-1,2-dioctanoyl-glycerol. CI-922 is also unable to inhibit the synergistic activation of PMNs by suboptimal concentrations of PMA and calcium ionophore A23187. These results suggest that CI-922 inhibits PMN activation at a site distal to signal transduction through the guanine nucleotide regulatory protein required for second messenger generation but proximal cophosphorylation reactions mediated by protein kinase C and calcium/calmodulin-dependent protein kinases.

  2. Cannabis extract, but not delta 1-tetrahydrocannabinol, inhibits human brain and liver monoamine oxidase.

    PubMed

    Schurr, A; Rigor, B M

    1984-01-01

    Mitochondrial monoamine oxidase (MAO) of human brain and liver was inhibited by low concentrations of cannabis extract (CE) and a cannabinoid fraction isolated from it. delta 1-Tetrahydrocannabinol (THC) did not elicit any inhibitory effect on the enzyme. The inhibition of MAO activity by CE and by its active fraction was more pronounced when the monoamine substrates 2-phenylethylamine (PEA) and benzylamine (BA) were used, as compared to the inhibition of the enzyme activity when 5-hydroxytryptamine was the substrate. The active cannabinoid fraction was found to be more potent than CE in inhibiting the activity of MAO with either substrate. The isolated fraction contains at least two cannabinoids with Rf values of 0.67 and 0.71 on silica gel thin layer chromatography (TLC), as determined with toluene/chloroform/methanol (100:10:1, by volume) as the solvent system. The findings of this study emphasize the need for further exploration of the potential of cannabis as a source for therapeutic agents.

  3. Human recombinant interleukin-1 beta inhibits nicotinic transmission in neurons of guinea pig pelvic plexus ganglia.

    PubMed

    Lin, J; Krier, J

    1995-12-01

    The actions of human recombinant interleukin-1 beta (hrIL-1 beta) were tested on guinea pig pelvic plexus ganglion neurons using intracellular electrophysiological methods in vitro. hrIL-1 beta caused membrane depolarization associated with a decreased input resistance or inward currents in 54% of neurons tested. hrIL-1 beta caused a hyperpolarization associated with an increase in input resistance or outward currents in 30% of neurons tested. hrIL-1 beta-evoked responses were not altered by hexamethonium (100 microM), atropine (0.5 microM), yohimbine (0.3 microM), or naloxone (1 microM), indicating that cholinergic, alpha 2-adrenergic, or opioid receptors were not involved. Drugs that inhibit Na+, Ca2+, or K+ channels did not change hrIL-1 beta-evoked responses. Stimulation of synaptic inputs to pelvic ganglion neurons evoked nicotinic cholinergic fast excitatory postsynaptic potentials (fEPSPs). hrIL-1 beta inhibited fEPSPs in 44% of neurons tested but had no effect on acetylcholine-induced depolarizations. An IL-1 beta receptor antagonist blocked all actions of hrIL-1 beta. In summary, hrIL-1 beta has excitatory and inhibitory actions on pelvic ganglion neurons. Inhibition of fEPSPs by hrIL-1 beta may be due to presynaptic inhibition of acetylcholine release.

  4. Molecular Mechanisms of Luteolin Induced Growth Inhibition and Apoptosis of Human Osteosarcoma Cells

    PubMed Central

    Wang, Yonghong; Kong, Daliang; Wang, Xinwei; Dong, Xiaoxiong; Tao, Yingying; Gong, Haiyang

    2015-01-01

    Luteolin is a flavone in medicinal plants as well as some vegetables and spices. It is a natural anti-oxidant with less pro-oxidant potential but apparently with a better safety profile. The purpose of this study was to investigate the molecular mechanism of luteolin-mediated apoptosis of MG-63 human osteosarcoma cells. MTT assay kit was employed to evaluate the effects of luteolin on MG-63 cells proliferation. Then, we performed Annexin V-FITC/PI to analyze the apoptotic rate of the cells. Furthermore, the inhibitory effects of luteolin on the expressions of BCL-2, BAX, Caspase-3 and Survivin were detected by Western blotting. As expected, luteolin (0.5, 2.5, 12.5 µg/mL) inhibited the growth of MG-63 cells by inhibiting cell proliferation and inducing cell apoptosis. Western blotting demonstrated that luteolin (0.5, 2.5, 12.5 µg/mL) inhibited the expressions of BCL-2, Caspase-3 and Survivin, and promoted the expression of BAX in MG-63 cells with a concentration dependent way. Luteolin can inhibit osteosarcoma cell proliferation and induce apoptosis effectively in a dose dependent manner through down-regulating the expression of BCL-2, Caspase-3 and Survivin proteins levels and up-regulating the expression of BAX protein level. These findings indicated that luteolin may be used as a novel herbal medicine for the treatment of osteosarcoma. PMID:25901161

  5. Galectin-3 inhibition sensitizes human renal cell carcinoma cells to arsenic trioxide treatment

    PubMed Central

    Xu, Yangyang; Gu, Xin; Gong, Mancheng; Guo, Guiying; Han, Kaiyu; An, Ruihua

    2013-01-01

    The anti-tumor effects of arsenic trioxide (ATO) were well established in acute promyelocytic leukemia, but not in renal cell carcinoma (RCC). Recent evidences indicate that galectin-3 (Gal-3) plays an anti-apoptotic role in chemotherapy induced tumor cell death. This study was intended to clarify the exact roles of Gal-3 performed in ATO-induced apoptosis in RCC cells. Weak apoptosis was observed in Gal-3-positive RCC cells (Caki-1, Caki-2, 786-0, and ACHN) following ATO treatment. However, ATO treatment upregulated Gal-3 expression concurrently caused a Synexin-cooperated translocation of Gal-3 from the nucleus to the cytoplasm. Gal-3-knockdown cells were more sensitive to ATO treatment as indicated by a strong mitochondria-dependent apoptosis following ATO treatment. Meanwhile, Gal-3 was found to inhibit ATO-induced apoptosis through enhancing Bcl-2 expression and stabilizing mitochondria. To confirm the results obtained from genetic method, we employed a Gal-3 inhibitor, modified citrus prectin (MCP), and co-treated the RCC cells with ATO. The cells showed an increased apoptosis in the syngeneic application of Gal-3 inhibition and ATO compared with ATO application alone. Based on these results, we conclude that Gal-3 inhibition sensitizes human renal cell carcinoma cells to ATO treatment through increasing mitochondria-dependent apoptosis. Our studies implicate synergetic application of ATO and Gal-3 inhibition as a potential strategy for RCC treatment. PMID:23917726

  6. Sulforaphane prevents human platelet aggregation through inhibiting the phosphatidylinositol 3-kinase/Akt pathway.

    PubMed

    Chuang, Wen-Ying; Kung, Po-Hsiung; Kuo, Chih-Yun; Wu, Chin-Chung

    2013-06-01

    Sulforaphane, a dietary isothiocyanate found in cruciferous vegetables, has been shown to exert beneficial effects in animal models of cardiovascular diseases. However, its effect on platelet aggregation, which is a critical factor in arterial thrombosis, is still unclear. In the present study, we show that sulforaphane inhibited human platelet aggregation caused by different receptor agonists, including collagen, U46619 (a thromboxane A2 mimic), protease-activated receptor 1 agonist peptide (PAR1-AP), and an ADP P2Y12 receptor agonist. Moreover, sulforaphane significantly reduced thrombus formation on a collagen-coated surface under whole blood flow conditions. In exploring the underlying mechanism, we found that sulforaphane specifically prevented phosphatidylinositol 3-kinase (PI3K)/Akt signalling, without markedly affecting other signlaling pathways involved in platelet aggregation, such as protein kinase C activation, calcium mobilisation, and protein tyrosine phosphorylation. Although sulforaphane did not directly inhibit the catalytic activity of PI3K, it caused ubiquitination of the regulatory p85 subunit of PI3K, and prevented PI3K translocation to membranes. In addition, sulforaphane caused ubiquitination and degradation of phosphoinositide-dependent kinase 1 (PDK1), which is required for Akt activation. Therefore, sulforaphane is able to inhibit the PI3K/Akt pathway at two distinct sites. In conclusion, we have demonstrated that sulforaphane prevented platelet aggregation and reduced thrombus formation in flow conditions; our data also support that the inhibition of the PI3K/Akt pathway by sulforaphane contributes it antiplatelet effects.

  7. Structural and Mechanistic Studies of Mofegiline Inhibition of Recombinant Human Monoamine Oxidase B

    PubMed Central

    Milczek, Erika M.; Bonivento, Daniele; Binda, Claudia; Mattevi, Andrea; McDonald, Ian A.; Edmondson, Dale E.

    2009-01-01

    Mechanistic and structural studies have been carried out to investigate the molecular basis for the irreversible inhibition of human MAO-B by mofegiline. Competitive inhibition with substrate shows an apparent Ki of 28 nM. Irreversible inhibition of MAO-B occurs with a 1:1 molar stoichiometry with no observable catalytic turnover. The absorption spectral properties of mofegiline inhibited MAO-B show features (λmax ≃ 450 nm) unlike those of traditional flavin N(5) or C(4a) adducts. Visible and near UV circular dichroism spectra of the mofegiline-MAO-B adduct shows a negative peak at 340 nm with an intensity similar to that of N(5) flavocyanine adducts. The x-ray crystal structure of the mofegiline-MAO-B adduct shows a covalent bond between the flavin cofactor N(5) with the distal allylamine carbon atom as well as the absence of the fluorine atom. A mechanism to explain these structural and spectral data is proposed. PMID:19053775

  8. Resveratrol compounds inhibit human holocarboxylase synthetase and cause a lean phenotype in Drosophila melanogaster

    PubMed Central

    Cordonier, Elizabeth L.; Adjam, Riem; Camara Teixeira, Daniel; Onur, Simone; Zbasnik, Richard; Read, Paul E.; Döring, Frank; Schlegel, Vicki L.; Zempleni, Janos

    2015-01-01

    Holocarboxylase synthetase (HLCS) is the sole protein-biotin ligase in the human proteome. HLCS has key regulatory functions in intermediary metabolism, including fatty acid metabolism, and in gene repression through epigenetic mechanisms. The objective of this study was to identify foodborne inhibitors of HLCS that alter HLCS-dependent pathways in metabolism and gene regulation. When libraries of extracts from natural products and chemically pure compounds were screened for HLCS inhibitor activity, resveratrol compounds in grape materials caused an HLCS inhibition of >98% in vitro. The potency of these compounds was piceatannol > resveratrol > piceid. Grape-borne compounds other than resveratrol metabolites also contributed toward HLCS inhibition, e.g., p-coumaric acid and cyanidin chloride. HLCS inhibitors had meaningful effects on body fat mass. When Drosophila melanogaster brummer mutants, which are genetically predisposed to storing excess amounts of lipids, were fed diets enriched with grape leaf extracts and piceid, body fat mass decreased by more than 30% in males and females. However, Drosophila responded to inhibitor treatment with an increase in the expression of HLCS, which elicited an increase in the abundance of biotinylated carboxylases in vivo. We conclude that mechanisms other than inhibition of HLCS cause body fat loss in flies. We propose that the primary candidate is the inhibition of the insulin receptor/Akt signaling pathway. PMID:26303405

  9. Cortisone and hydrocortisone inhibit human Kv1.3 activity in a non-genomic manner.

    PubMed

    Yu, Jing; Park, Mi-Hyeong; Choi, Se-Young; Jo, Su-Hyun

    2015-06-01

    Glucocorticoids are hormones released in response to stress that are involved in various physiological processes including immune functions. One immune-modulating mechanism is achieved by the Kv1.3 voltage-dependent potassium channel, which is expressed highly in lymphocytes including effector memory T lymphocytes (TEM). Although glucocorticoids are known to inhibit Kv1.3 function, the detailed inhibitory mechanism is not yet fully understood. Here we studied the rapid non-genomic effects of cortisone and hydrocortisone on the human Kv1.3 channel expressed in Xenopus oocytes. Both cortisone and hydrocortisone reduced the amplitude of the Kv1.3 channel current in a concentration-dependent manner. Both cortisone and hydrocortisone rapidly and irreversibly inhibited Kv1.3 currents, eliminating the possibility of genomic regulation. Inhibition rate was stable relative to the degree of depolarization. Kinetically, cortisone altered the activating gate of Kv1.3 and hydrocortisone interacted with this channel in an open state. These results suggest that cortisone and hydrocortisone inhibit Kv1.3 currents via a non-genomic mechanism, providing a mechanism for the immunosuppressive effects of glucocorticoids.

  10. AMPK-independent inhibition of human macrophage ER stress response by AICAR

    PubMed Central

    Boß, Marcel; Newbatt, Yvette; Gupta, Sahil; Collins, Ian; Brüne, Bernhard; Namgaladze, Dmitry

    2016-01-01

    Obesity-associated insulin resistance is driven by inflammatory processes in response to metabolic overload. Obesity-associated inflammation can be recapitulated in cell culture by exposing macrophages to saturated fatty acids (SFA), and endoplasmic reticulum (ER) stress responses essentially contribute to pro-inflammatory signalling. AMP-activated protein kinase (AMPK) is a central metabolic regulator with established anti-inflammatory actions. Whether pharmacological AMPK activation suppresses SFA-induced inflammation in a human system is unclear. In a setting of hypoxia-potentiated inflammation induced by SFA palmitate, we found that the AMP-mimetic AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) potently suppressed upregulation of ER stress marker mRNAs and pro-inflammatory cytokines. Furthermore, AICAR inhibited macrophage ER stress responses triggered by ER-stressors thapsigargin or tunicamycin. Surprisingly, AICAR acted independent of AMPK or AICAR conversion to 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranosyl monophosphate (ZMP) while requiring intracellular uptake via the equilibrative nucleoside transporter (ENT) ENT1 or the concentrative nucleoside transporter (CNT) CNT3. AICAR did not affect the initiation of the ER stress response, but inhibited the expression of major ER stress transcriptional effectors. Furthermore, AICAR inhibited autophosphorylation of the ER stress sensor inositol-requiring enzyme 1α (IRE1α), while activating its endoribonuclease activity in vitro. Our results suggest that AMPK-independent inhibition of ER stress responses contributes to anti-inflammatory and anti-diabetic effects of AICAR. PMID:27562249

  11. Inhibition of Kv1.3 Channels in Human Jurkat T Cells by Xanthohumol and Isoxanthohumol.

    PubMed

    Gąsiorowska, Justyna; Teisseyre, Andrzej; Uryga, Anna; Michalak, Krystyna

    2015-08-01

    Using whole-cell patch-clamp technique, we investigated influence of selected compounds from groups of prenylated chalcones and flavonoids: xanthohumol and isoxanthohumol on the activity of Kv1.3 channels in human leukemic Jurkat T cells. Obtained results provide evidence that both examined compounds were inhibitors of Kv1.3 channels in these cells. The inhibitory effects occurred in a concentration-dependent manner. The estimated value of the half-blocking concentration (EC50) was about 3 μM for xanthohumol and about 7.8 μM for isoxanthohumol. The inhibition of Kv1.3 channels by examined compounds was not complete. Upon an application of the compounds at the maximal concentrations equal to 30 μM, the activity of Kv1.3 channels was inhibited to about 0.13 of the control value. The inhibitory effect was reversible. The application of xanthohumol and isoxanthohumol did not change the currents' activation and inactivation rate. These results may confirm our earlier hypothesis that the presence of a prenyl group in a molecule is a factor that facilitates the inhibition of Kv1.3 channels by compounds from the groups of flavonoids and chalcones. The inhibition of Kv1.3 channels might be involved in antiproliferative and proapoptotic effects of the compounds observed in cancer cell lines expressing these channels.

  12. Rat and human colonic mucins bind to and inhibit adherence lectin of Entamoeba histolytica.

    PubMed Central

    Chadee, K; Petri, W A; Innes, D J; Ravdin, J I

    1987-01-01

    Establishment of adherence by Entamoeba histolytica is mediated by a 170-kD Gal/GalNAc inhibitable lectin and is required for cytolysis and phagocytosis of mammalian target cells. We studied the biochemical mechanisms of the in vitro interaction between rat and human colonic mucins and axenic E. histolytica trophozoites. Crude mucus prevented amebic adherence to Chinese hamster ovary (CHO) cells by up to 70%. Purification of the colonic mucins by Sepharose 4B chromatography, nuclease digestion, and cesium chloride gradient centrifugation resulted in a 1,000-fold enrichment of the inhibitory mucins. Purified rat mucin inhibited amebic adherence to and cytolysis of homologous rat colonic epithelial cells. Oxidation and enzymatic cleavage of rat mucin Gal and GalNAc residues completely abrogated mucin inhibition of amebic adherence. The binding of rat 125I-mucin to amebae was galactose specific, saturable, reversible, and pH dependent. A monoclonal antibody specific for the 170-kD amebic Gal/GalNAc lectin completely inhibited the binding of rat 125I-mucin. Rat mucin bound to Affigel affinity purified the amebic lectin from conditioned medium. Colonic mucin glycoproteins act as an important host defense by binding to the parasite's adherence lectin, thus preventing amebic attachment to and cytolysis of host epithelial cells. Images PMID:2890655

  13. Lovastatin inhibits human B lymphoma cell proliferation by reducing intracellular ROS and TRPC6 expression

    PubMed Central

    Song, Xiang; Liu, Bing-Chen; Lu, Xiao-Yu; Yang, Li-Li; Zhai, Yu-Jia; Eaton, Amity F.; Thai, Tiffany L.; Eaton, Douglas C.; Ma, He-Ping; Shen, Bao-Zhong

    2014-01-01

    Clinical evidence suggests that statins reduce cancer incidence and mortality. However, there is lack of in vitro data to show the mechanism by which statins can reduce the malignancies of cancer cells. We used a human B lymphoma Daudi cells as a model and found that lovastatin inhibited, whereas exogenous cholesterol (Cho) stimulated, proliferation cell cycle progression in control Daudi cells, but not in the cells when transient receptor potential canonical 6 (TRPC6) channel was knocked down. Lovastatin decreased, whereas Cho increased, the levels of intracellular reactive oxygen species (ROS) respectively by decreasing or increasing the expression of p47-phox and gp91-phox (NOX2). Reducing intracellular ROS with either a mimetic superoxide dismutase (TEMPOL) or a NADPH oxidase inhibitor (apocynin) inhibited cell proliferation, particularly in Cho-treated cells. The effects of TEMPOL or apocynin were mimicked by inhibition of TRPC6 with SKF-96365. Lovastatin decreased TRPC6 expression and activity via a Cho-dependent mechanism, whereas Cho increased TRPC6 expression and activity via an ROS-dependent mechanism. Consistent with the fact that TRPC6 is a Ca2+-permeable channel, lovastatin decreased, but Cho increased, intracellular Ca2+ also via ROS. These data suggest that lovastatin inhibits malignant B cell proliferation by reducing membrane Cho, intracellular ROS, TRPC6 expression and activity, and intracellular Ca2+. PMID:24518247

  14. Lovastatin inhibits human B lymphoma cell proliferation by reducing intracellular ROS and TRPC6 expression.

    PubMed

    Song, Xiang; Liu, Bing-Chen; Lu, Xiao-Yu; Yang, Li-Li; Zhai, Yu-Jia; Eaton, Amity F; Thai, Tiffany L; Eaton, Douglas C; Ma, He-Ping; Shen, Bao-Zhong

    2014-05-01

    Clinical evidence suggests that statins reduce cancer incidence and mortality. However, there is lack of in vitro data to show the mechanism by which statins can reduce the malignancies of cancer cells. We used a human B lymphoma Daudi cells as a model and found that lovastatin inhibited, whereas exogenous cholesterol (Cho) stimulated, proliferation cell cycle progression in control Daudi cells, but not in the cells when transient receptor potential canonical 6 (TRPC6) channel was knocked down. Lovastatin decreased, whereas Cho increased, the levels of intracellular reactive oxygen species (ROS) respectively by decreasing or increasing the expression of p47-phox and gp91-phox (NOX2). Reducing intracellular ROS with either a mimetic superoxide dismutase (TEMPOL) or an NADPH oxidase inhibitor (apocynin) inhibited cell proliferation, particularly in Cho-treated cells. The effects of TEMPOL or apocynin were mimicked by inhibition of TRPC6 with SKF-96365. Lovastatin decreased TRPC6 expression and activity via a Cho-dependent mechanism, whereas Cho increased TRPC6 expression and activity via an ROS-dependent mechanism. Consistent with the fact that TRPC6 is a Ca(2+)-permeable channel, lovastatin decreased, but Cho increased, intracellular Ca(2+) also via ROS. These data suggest that lovastatin inhibits malignant B cell proliferation by reducing membrane Cho, intracellular ROS, TRPC6 expression and activity, and intracellular Ca(2+). Copyright © 2014 Elsevier B.V. All rights reserved.

  15. In vitro inhibition of superoxide anion production and superoxide dismutase activity by zinc in human spermatozoa.

    PubMed

    Gavella, M; Lipovac, V; Vucić, M; Sverko, V

    1999-08-01

    The in vitro effect of zinc on superoxide anion (O2-) generation and on SOD-like activity in spermatozoa of infertile men was investigated. The formation of superoxide anion was stimulated by NADPH and the level of superoxide anion was measured by the reduction of ferricytochrome c. Both Percoll-isolated (n = 14) and washed spermatozoa (n = 14) exposed to 1 mmol/L zinc (60 min, 37 degrees C), released less (p < 0.002 and p < 0.04, respectively) superoxide anions than did zinc-untreated spermatozoa. These results implicate a possible role for zinc as a scavenger of excessive superoxide anions produced by defective spermatozoa in semen after ejaculation. Additionally, zinc was found to dose-dependently inhibit superoxide dismutase (SOD)-like activity of spermatozoa in vitro. The inhibition of SOD-like activity by an equal concentration of zinc (1 mmol/L) was less pronounced in oligospermic (p < 0.002; n = 16) and asthenozoospermic (p < 0.0005; n = 20) than in normozoospermic samples (p < 0.0001; n = 20). This differential ability of zinc to inhibit SOD-like activity may be relevant to the physiological function of spermatozoa in fertilization. The evidence that zinc may elicit an inhibition of both superoxide anion production and SOD-like activity in human spermatozoa, indicate the existence of novel, zinc-related mechanism(s) involved in the oxidative events occurring after ejaculation, with a possible modulatory effect on germ cell function.

  16. Vasoactive intestinal peptide inhibits fMLP-induced respiratory burst in human lymphocytes.

    PubMed

    Bellido, L; López-González, M A; Pedrera, C; Lucas, M

    1994-01-01

    N-Formyl-Methionyl-Leucyl-Phenylalanine (fMLP) induced in lymphocytes the production of reactive oxygen intermediates in a process which was inhibited by the presence of Vasoactive Intestinal Peptide (VIP) in a dose-dependent response at VIP concentrations in the range 10(-10)-10(-7) M. The dissociation constant for the high-affinity receptors of VIP agrees with the ID50 of the activation of adenylate cyclase which are close to 0.2 nM VIP, whereas the ID50 for the inhibition by VIP of fMLP-induced chemiluminescence approaches to 5 nM VIP. Both IBMX and Forskolin produced in lymphocytes an inhibition of fMLP-induced chemiluminescence. The degree of inhibition was ascertained to be additive in the presence of the above indicated agents and suboptimal concentrations of VIP. The saturation by cAMP of its putative target, the regulatory subunit of protein kinase A, appears to be required for the onset of the inhibitory effect of VIP. This study provides evidence of the molecular signal, namely cAMP, which provokes an inhibitory effect on chemoatractant-stimulated human lymphocytes and further support a role for VIP as a mediator in the neuroimmune system.

  17. Inhibition of human platelet phospholipase A/sub 2/ by mono(2-ethylhexyl)phthalate

    SciTech Connect

    Labow, R.S.; Meek, E.; Adams, G.A.; Rock, G.

    1988-06-01

    There is evidence that the carcinogenic and teratogenic effects attributed to the plasticizer di(2-ethylhexyl)phthalate (DEHP) are due to its major metabolite mono(2-ethylhexyl)phthalate (MEHP). MEHP is also formed ex vivo by a plasma enzyme in blood products stored in polyvinyl chloride (PVC) DEHP plastic containers. People who receive large amounts of blood products, such as hemophiliacs or patients undergoing hemodialysis, cardiopulmonary bypass, or massive transfusion, are exposed to significant levels of plasticizer. In this study, the platelet was used to show that MEHP inhibits phospholipase A/sub 2/ (PLA/sub 2/), one of the enzymes important in the release of arachidonic acid from membrane phospholipids. PLA/sub 2/ was measured by the liberation of /sup 14/C-arachidonic acid from 1-stearoyl-2-(1-/sup 14/C)arachidonyl-L-3-phosphatidylcholine. MEHP inhibits PLA/sub 2/ activity noncompetitively in intact human platelets and lysates with a K/sub i/ of 3.7 x 10/sup -4/ M. DEHP does not inhibit PLA/sub 2/ in whole platelets. Inhibition of PLA/sub 2/ by MEHP occurs at only three times the circulating level of MEHP measured in neonates undergoing exchange transfusion and 20-fold the levels experienced by patients during cardiopulmonary bypass. Therefore, infants and adult patients with multisystem failure who accumulate MEHP in their blood may be at risk for decreased platelet function.

  18. Aminomethylphosphonic acid inhibits growth and metastasis of human prostate cancer in an orthotopic xenograft mouse model

    PubMed Central

    Parajuli, Keshab Raj; Zhang, Qiuyang; Liu, Sen; You, Zongbing

    2016-01-01

    Aminomethylphosphonic acid (AMPA) has been shown to inhibit prostate cancer cell growth in vitro. The purpose of the present study was to determine if AMPA could inhibit growth and metastasis of prostate cancer in vivo. Human prostate cancer PC-3-LacZ-luciferase cells were implanted into the ventral lateral lobes of the prostate in 39 athymic Nu/Nu nude male mice. Seven days later, mice were randomized into the control group (n = 14, treated intraperitoneally with phosphate buffered saline), low dose group (n = 10, treated intraperitoneally with AMPA at 400 mg/kg body weight/day), and high dose group (n = 15, treated intraperitoneally with AMPA at 800 mg/kg body weight/day). Tumor growth and metastasis were examined every 4-7 days by bioluminescence imaging of live mice. We found that AMPA treatment significantly inhibited growth and metastasis of orthotopic xenograft prostate tumors and prolonged the survival time of the mice. AMPA treatment decreased expression of BIRC2 and activated caspase 3, leading to increased apoptosis in the prostate tumors. AMPA treatment decreased expression of cyclin D1. AMPA treatment also reduced angiogenesis in the prostate tumors. Taken together, these results demonstrate that AMPA can inhibit prostate cancer growth and metastasis, suggesting that AMPA may be developed into a therapeutic agent for the treatment of prostate cancer. PMID:26840261

  19. beta-Carboline alkaloids in Peganum harmala and inhibition of human monoamine oxidase (MAO).

    PubMed

    Herraiz, T; González, D; Ancín-Azpilicueta, C; Arán, V J; Guillén, H

    2010-03-01

    Peganum harmala L. is a multipurpose medicinal plant increasingly used for psychoactive recreational purposes (Ayahuasca analog). Harmaline, harmine, harmalol, harmol and tetrahydroharmine were identified and quantified as the main beta-carboline alkaloids in P. harmala extracts. Seeds and roots contained the highest levels of alkaloids with low levels in stems and leaves, and absence in flowers. Harmine and harmaline accumulated in dry seeds at 4.3% and 5.6% (w/w), respectively, harmalol at 0.6%, and tetrahydroharmine at 0.1% (w/w). Roots contained harmine and harmol with 2.0% and 1.4% (w/w), respectively. Seed extracts were potent reversible and competitive inhibitors of human monoamine oxidase (MAO-A) with an IC(50) of 27 microg/l whereas root extracts strongly inhibited MAO-A with an IC(50) of 159 microg/l. In contrast, they were poor inhibitors of MAO-B. Inhibition of MAO-A by seed extracts was quantitatively attributed to harmaline and harmine whereas inhibition by root extracts came from harmine with no additional interferences. Stems and leaves extracts were poor inhibitors of MAO. The potent inhibition of MAO-A by seed and root extracts of P. harmala containing beta-carbolines should contribute to the psychopharmacological and toxicological effects of this plant and could be the basis for its purported antidepressant actions.

  20. Aminomethylphosphonic acid inhibits growth and metastasis of human prostate cancer in an orthotopic xenograft mouse model.

    PubMed

    Parajuli, Keshab Raj; Zhang, Qiuyang; Liu, Sen; You, Zongbing

    2016-03-01

    Aminomethylphosphonic acid (AMPA) has been shown to inhibit prostate cancer cell growth in vitro. The purpose of the present study was to determine if AMPA could inhibit growth and metastasis of prostate cancer in vivo. Human prostate cancer PC-3-LacZ-luciferase cells were implanted into the ventral lateral lobes of the prostate in 39 athymic Nu/Nu nude male mice. Seven days later, mice were randomized into the control group (n = 14, treated intraperitoneally with phosphate buffered saline), low dose group (n = 10, treated intraperitoneally with AMPA at 400 mg/kg body weight/day), and high dose group (n = 15, treated intraperitoneally with AMPA at 800 mg/kg body weight/day). Tumor growth and metastasis were examined every 4-7 days by bioluminescence imaging of live mice. We found that AMPA treatment significantly inhibited growth and metastasis of orthotopic xenograft prostate tumors and prolonged the survival time of the mice. AMPA treatment decreased expression of BIRC2 and activated caspase 3, leading to increased apoptosis in the prostate tumors. AMPA treatment decreased expression of cyclin D1. AMPA treatment also reduced angiogenesis in the prostate tumors. Taken together, these results demonstrate that AMPA can inhibit prostate cancer growth and metastasis, suggesting that AMPA may be developed into a therapeutic agent for the treatment of prostate cancer.

  1. Multicarotenoids at Physiological Levels Inhibit Metastasis in Human Hepatocarcinoma SK-Hep-1 Cells.

    PubMed

    Chen, Huei-Yan; Yang, Chih-Min; Chen, Jen-Yin; Yueh, Te-Cheng; Hu, Miao-Lin

    2015-01-01

    Several studies have demonstrated that single carotenoid, including lycopene, β-carotene, and α-carotene, exhibits antimetastatic effects; however, little is known whether multicarotenoids have similar effects. Herein, we investigated the antimetastatic effect of multicarotenoids at physiological serum levels in Taiwanese (MCT at 1.4 μM) and American (MCA at 1.8 μM) populations using human hepatocarcinoma SK-Hep-1 cells in comparison with single carotenoid, such as lycopene (0.3 or 0.6 μM, respectively), α-carotene (0.1 μM), β-carotene (0.4 μM), lutein (0.4 or 0.5 μM, respectively), and β-cryptoxanthin (0.2 μM). Results reveal that MCA treatment exhibited an additive inhibition on invasion, migration and adhesion at 24 and 48 h of incubation, whereas MCT treatment possessed additive inhibition at 48 h of incubation. The antimetastatic action of MCT and MCA involved additive reduction on activities of matrix metalloproteinase (MMP)-2, -9, and protein expression of Rho and Rac 1 but additive promotion on protein expression of tissue inhibitor of MMP (TIMP)-1 and -2. All of these effects were stronger in MCA than in MCT at 24 and 48 h of incubation. These results demonstrate that multi-carotenoids effectively inhibit metastasis of human hepatocarcinoma SK-Hep-1 cells. More in vivo studies are needed to confirm these findings.

  2. Human IgA inhibits adherence of Acanthamoeba polyphaga to epithelial cells and contact lenses.

    PubMed

    Campos-Rodríguez, Rafael; Oliver-Aguillón, Gabriela; Vega-Pérez, Luz M; Jarillo-Luna, Adriana; Hernández-Martínez, Dolores; Rojas-Hernández, Saúl; Rodríguez-Monroy, Marco A; Rivera-Aguilar, Víctor; González-Robles, Arturo

    2004-09-01

    Specific anti-Acanthamoeba IgA antibodies have been detected in the serum and tears of patients and healthy individuals. However, the role of human secretory IgA antibodies in inhibiting the adherence of Acanthamoeba had not been previously investigated. Therefore, the purpose of this study was to purify secretory IgA from human colostrum and analyze its effect on the adherence of Acanthamoeba trophozoites to contact lenses and Madin-Darby canine kidney (MDCK) cells. IgA antibodies to Acanthamoeba polyphaga in colostrum of healthy women as well as in saliva and serum of healthy subjects were analyzed by ELISA and Western blot analysis. In serum, saliva, and colostrum, we detected IgA antibodies that recognized several antigens of A. polyphaga. In addition, colostrum and IgA antibodies purified from it inhibited adherence of A. polyphaga trophozoites to contact lenses and MDCK cells. These results suggest that IgA antibodies may participate in the resistance to the amoebic infection, probably by inhibiting the adherence of the trophozoites to contact lenses and corneal epithelial cells.

  3. Chloroquine inhibits human CD4+ T-cell activation by AP-1 signaling modulation

    PubMed Central

    Schmidt, Ralf L. J.; Jutz, Sabrina; Goldhahn, Katrin; Witzeneder, Nadine; Gerner, Marlene C.; Trapin, Doris; Greiner, Georg; Hoermann, Gregor; Steiner, Guenter; Pickl, Winfried F.; Burgmann, Heinz; Steinberger, Peter; Ratzinger, Franz; Schmetterer, Klaus G.

    2017-01-01

    Chloroquine (CQ) is widely used as an anti-inflammatory therapeutic for rheumatic diseases. Although its modes of action on the innate immune system are well described, there is still insufficient knowledge about its direct effects on the adaptive immune system. Thus, we evaluated the influence of CQ on activation parameters of human CD4+ T-cells. CQ directly suppressed proliferation, metabolic activity and cytokine secretion of T-cells following anti-CD3/anti-CD28 activation. In contrast, CQ showed no effect on up-regulation of T-cell activation markers. CQ inhibited activation of all T helper cell subsets, although IL-4 and IL-13 secretion by Th2 cells were less influenced compared to other Th-specific cytokines. Up to 10 μM, CQ did not reduce cell viability, suggesting specific suppressive effects on T-cells. These properties of CQ were fully reversible in re-stimulation experiments. Analyses of intracellular signaling showed that CQ specifically inhibited autophagic flux and additionally activation of AP-1 by reducing phosphorylation of c-JUN. This effect was mediated by inhibition of JNK catalytic activity. In summary, we characterized selective and reversible immunomodulatory effects of CQ on human CD4+ T-cells. These findings provide new insights into the biological actions of JNK/AP-1 signaling in T-cells and may help to expand the therapeutic spectrum of CQ. PMID:28169350

  4. Inhibition of human α7 nicotinic acetylcholine receptors by cyclic monoterpene carveol.

    PubMed

    Lozon, Yosra; Sultan, Ahmed; Lansdell, Stuart J; Prytkova, Tatiana; Sadek, Bassem; Yang, Keun-Hang Susan; Howarth, Frank Christopher; Millar, Neil S; Oz, Murat

    2016-04-05

    Cyclic monoterpenes are a group of phytochemicals with antinociceptive, local anesthetic, and anti-inflammatory actions. Effects of cyclic monoterpenes including vanilin, pulegone, eugenole, carvone, carvacrol, carveol, thymol, thymoquinone, menthone, and limonene were investigated on the functional properties of the cloned α7 subunit of the human nicotinic acetylcholine receptor expressed in Xenopus oocytes. Monoterpenes inhibited the α7 nicotinic acetylcholine receptor in the order carveol>thymoquinone>carvacrol>menthone>thymol>limonene>eugenole>pulegone≥carvone≥vanilin. Among the monoterpenes, carveol showed the highest potency on acetylcholine-induced responses, with IC50 of 8.3µM. Carveol-induced inhibition was independent of the membrane potential and could not be reversed by increasing the concentration of acetylcholine. In line with functional experiments, docking studies indicated that cyclic monoterpenes such as carveol may interact with an allosteric site located in the α7 transmembrane domain. Our results indicate that cyclic monoterpenes inhibit the function of human α7 nicotinic acetylcholine receptors, with varying potencies.

  5. Effects of Mitochondrial Uncoupling Protein 2 Inhibition by Genipin in Human Cumulus Cells

    PubMed Central

    Ge, Hongshan; Zhang, Fan; Shan, Dan; Chen, Hua; Wang, Xiaona; Ling, Chao; Xi, HaiTao; Huang, Jianying; Zhu, ChunFang; Lv, Jeiqiang

    2015-01-01

    UCP2 plays a physiological role by regulating mitochondrial biogenesis, maintaining energy balance, ROS elimination, and regulating cellular autophagy in numerous tissues. But the exact roles of UCP2 in cumulus cells are still not clear. Genipin, a special UCP2 inhibitor, was added into the cultural medium to explore the roles of UCP2 in human cumulus cells. There were no significant differences in ATP and mitochondrial membrane potential levels in cumulus cells from UCP2 inhibiting groups as compared with the control. The levels of ROS and Mn-SOD were markedly elevated after UCP2 inhibited Genipin. However, the ratio of reduced GSH to GSSG significantly declined after treatment with Genipin. UCP2 inhibition by Genipin also resulted in obvious increase in the active caspase-3, which accompanied the decline of caspase-3 mRNA. The level of progesterone in culture medium declined obviously after Genipin treatment. But there was no significant difference in estradiol concentrations. This study indicated that UCP2 is expressed in human cumulus cells and plays important roles on mediate ROS production, apoptotic process, and steroidogenesis, suggesting UCP2 may be involved in regulation of follicle development and oocyte maturation and quality. PMID:26356408

  6. Inhibition of Cytochrome P450 by Propolis in Human Liver Microsomes

    PubMed Central

    Ryu, Chang Seon; Oh, Soo Jin; Oh, Jung Min; Lee, Ji-Yoon; Lee, Sang Yoon; Chae, Jung-woo; Kwon, Kwang-il; Kim, Sang Kyum

    2016-01-01

    Although propolis is one of the most popular functional foods for human health, there have been no comprehensive studies of herb-drug interactions through cytochrome P450 (CYP) inhibition. The purpose of this study was to determine the inhibitory effects of propolis on the activities of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and 3A4 using pooled human liver microsomes (HLMs). Propolis inhibited CYP1A2, CYP2E1 and CYP2C19 with an IC50 value of 6.9, 16.8, and 43.1 μg/mL, respectively, whereas CYP2A6, 2B6, 2C9, 2D6, and 3A4 were unaffected. Based on half-maximal inhibitory concentration shifts between microsomes incubated with and without nicotinamide adenine dinucleotide phosphate, propolis-induced CYP1A2, CYP2C19, and CYP2E1 inhibition was metabolism-independent. To evaluate the interaction potential between propolis and therapeutic drugs, the effects of propolis on metabolism of duloxetine, a serotonin-norepinephrine reuptake inhibitor, were determined in HLMs. CYP1A2 and CYP2D6 are involved in hydroxylation of duloxetine to 4-hydroxy duloxetine, the major metabolite, which was decreased following propolis addition in HLMs. These results raise the possibility of interactions between propolis and therapeutic drugs metabolized by CYP1A2. PMID:27437087

  7. Thymus vulgaris (thyme) inhibits proliferation, adhesion, migration, and invasion of human colorectal cancer cells.

    PubMed

    Al-Menhali, Afnan; Al-Rumaihi, Aisha; Al-Mohammed, Hana; Al-Mazrooey, Hana; Al-Shamlan, Maryam; AlJassim, Meaad; Al-Korbi, Noof; Eid, Ali Hussein

    2015-01-01

    Colorectal cancer (CRC) remains one of the most common malignancies and a leading cause of cancer-related deaths. Its prognosis remains poor for patients with several grades of this disease. This underscores the need for alternative modalities, such as herbal medicines, to treat this disease. A commonly used plant that appears to be of high medicinal value is Thymus vulgaris L. However, the effects of this plant on the malignant behavior of human CRC cells remains poorly investigated. This study was undertaken to determine the anticancer efficacy of T. vulgaris extract (TVE) in CRC cells. Our results show that TVE inhibits proliferation in a concentration- and time-dependent fashion. This decreased proliferation was concomitant with increased apoptotic cell death as evidenced by increased caspase3/7 activity. Moreover, TVE also decreased adhesion to fibronectin in a concentration-dependent manner. The migratory and invasive capacities of HCT116 cells were significantly inhibited by TVE. Taken together, these data suggest that the TVE inhibits malignant phenotype of colon cancer cells. Therefore, T. vulgaris could have an anticancer effect and that some of its bioactive compounds may prove to be effective treatment modalities for human CRC.

  8. Pharmacologic inhibition of fatty acid oxidation sensitizes human leukemia cells to apoptosis induction

    PubMed Central

    Samudio, Ismael; Harmancey, Romain; Fiegl, Michael; Kantarjian, Hagop; Konopleva, Marina; Korchin, Borys; Kaluarachchi, Kumar; Bornmann, William; Duvvuri, Seshagiri; Taegtmeyer, Heinrich; Andreeff, Michael

    2009-01-01

    The traditional view is that cancer cells predominately produce ATP by glycolysis, rather than by oxidation of energy-providing substrates. Mitochondrial uncoupling — the continuing reduction of oxygen without ATP synthesis — has recently been shown in leukemia cells to circumvent the ability of oxygen to inhibit glycolysis, and may promote the metabolic preference for glycolysis by shifting from pyruvate oxidation to fatty acid oxidation (FAO). Here we have demonstrated that pharmacologic inhibition of FAO with etomoxir or ranolazine inhibited proliferation and sensitized human leukemia cells — cultured alone or on bone marrow stromal cells — to apoptosis induction by ABT-737, a molecule that releases proapoptotic Bcl-2 proteins such as Bak from antiapoptotic family members. Likewise, treatment with the fatty acid synthase/lipolysis inhibitor orlistat also sensitized leukemia cells to ABT-737, which supports the notion that fatty acids promote cell survival. Mechanistically, we generated evidence suggesting that FAO regulates the activity of Bak-dependent mitochondrial permeability transition. Importantly, etomoxir decreased the number of quiescent leukemia progenitor cells in approximately 50% of primary human acute myeloid leukemia samples and, when combined with either ABT-737 or cytosine arabinoside, provided substantial therapeutic benefit in a murine model of leukemia. The results support the concept of FAO inhibitors as a therapeutic strategy in hematological malignancies. PMID:20038799

  9. Prostaglandin E₂ inhibits human lung fibroblast chemotaxis through disparate actions on different E-prostanoid receptors.

    PubMed

    Li, Ying-Ji; Wang, Xing-Qi; Sato, Tadashi; Kanaji, Nobuhiro; Nakanishi, Masanori; Kim, Miok; Michalski, Joel; Nelson, Amy J; Sun, Jian-Hong; Farid, Maha; Basma, Hesham; Patil, Amol; Toews, Myron L; Liu, Xiangde; Rennard, Stephen I

    2011-01-01

    The migration of fibroblasts is believed to play a key role in both normal wound repair and abnormal tissue remodeling. Prostaglandin E (PGE)(2), a mediator that can inhibit many fibroblast functions including chemotaxis, was reported to be mediated by the E-prostanoid (EP) receptor EP2. PGE(2), however, can act on four receptors. This study was designed to determine if EP receptors, in addition to EP2, can modulate fibroblast chemotaxis. Using human fetal lung fibroblasts, the expression of all four EP receptors was demonstrated by Western blotting. EP2-selective and EP4-selective agonists inhibited both chemotaxis toward fibronectin in the blindwell assay and migration in a wound-closure assay. In contrast, EP1-selective and EP3-selective agonists stimulated cell migration in both assay systems. These results were confirmed using EP-selective antagonists. The role of both EP2 and EP4 receptors in mediating the PGE(2) inhibition of chemotaxis was also confirmed by small interfering RNA suppression. Furthermore, the role of EP receptors was confirmed by blocking the expected signaling pathways. Taken together, these results demonstrate that PGE(2) can act on multiple EP receptors in human lung fibroblasts, to exert disparate effects. Alterations in EP receptor expression may have the potential to alter PGE(2) action. Targeting specific EP receptors may offer therapeutic opportunities in conditions characterized by abnormal tissue repair and remodeling.

  10. Otilonium bromide inhibits calcium entry through L-type calcium channels in human intestinal smooth muscle.

    PubMed

    Strege, P R; Evangelista, S; Lyford, G L; Sarr, M G; Farrugia, G

    2004-04-01

    Otilonium bromide (OB) is used as an intestinal antispasmodic. The mechanism of action of OB is not completely understood. As Ca(2+) entry into intestinal smooth muscle is required to trigger contractile activity, our hypothesis was that OB blocked Ca(2+) entry through L-type Ca(2+) channels. Our aim was to determine the effects of OB on Ca(2+), Na(+) and K(+) ion channels in human jejunal circular smooth muscle cells and on L-type Ca(2+) channels expressed heterologously in HEK293 cells. Whole cell currents were recorded using standard patch clamp techniques. Otilonium bromide (0.09-9 micromol L(-1)) was used as this reproduced clinical intracellular concentrations. In human circular smooth muscle cells, OB inhibited L-type Ca(2+) current by 25% at 0.9 micromol L(-1) and 90% at 9 micromol L(-1). Otilonium bromide had no effect on Na(+) or K(+) currents. In HEK293 cells, 1 micromol L(-1) OB significantly inhibited the expressed L-type Ca(2+) channels. Truncation of the alpha(1C) subunit C and N termini did not block the inhibitory effects of OB. Otilonium bromide inhibited Ca(2+) entry through L-type Ca(2+) at concentrations similar to intestinal tissue levels. This effect may underlie the observed muscle relaxant effects of the drug.

  11. Inhibition of UL54 and UL97 genes of human cytomegalovirus by RNA interference.

    PubMed

    Shin, M-C; Hong, S-K; Yoon, J-S; Park, S-S; Lee, S-G; Lee, D-G; Min, W-S; Shin, W-S; Paik, S-Y

    2006-01-01

    Short interfering RNAs (siRNAs), namely siUL54-1 and siU54-2 targeting UL54 (DNA polymerase) gene, and siUL97-1 and siUL97-2 targeting UL97 (phosphotransferase) gene, were used to inhibit respective genes of Human cytomegalovirus (HCMV) and consequently the virus infection process in human foreskin fibroblast (HFF) cultures. The virus infection was monitored by cell morphology (CPE), levels of UL83 and IE86 mRNAs, and virus antigen. The results showed that siUL97-2 remarkably inhibited viral CPE while other siRNAs were less inhibitory. The siRNAs reduced the levels of UL83 mRNA but not that of IE86 mRNA; again, siUL97-2 was most inhibitory. Particularly, siUL97-2 reduced the UL83 mRNA level 14, 19, 203, and 37 times at 24, 48, 72, and 96 hrs post infection (p.i.), respectively. When tested for the effect on viral antigen by immunofluorescent assay (IFA), UL97-2 exerted a marked inhibition. These results demonstrate the effectiveness of siRNAs against experimental HCMV infection and indicate their therapeutic potential.

  12. Recombinant human vascular endothelial growth factor receptor 1 effectively inhibits angiogenesis in vivo.

    PubMed

    Wang, Jinliang; Shi, Minglei; Xi, Yongyi; Gao, Lihua; Zhang, Guanyi; Shao, Yong; Chen, Huipeng; Hu, Xianwen

    2015-05-01

    Vascular endothelial growth factor (VEGF) plays an important role in both physiological and pathological angiogenesis. VEGF receptor‑1 (VEGFR‑1) acts as a decoy VEGF receptor that enables the regulation of VEGF on the vascular endothelium. In the present study, the recombinant human VEGFR1D1‑3/Fc (rhVEGFR‑1), which contains key domains for VEGF binding, was cloned and expressed in Chinese hamster ovary (CHO) cells. The rhVEGFR‑1 protein was purified using protein‑A affinity chromatography. The molecular weight of rhVEGFR‑1 was found to be ~162 and 81 kD in non‑reducing and reducing SDS‑PAGE, respectively. The majority of the final protein products were in the dimeric conformation. Western blot analysis revealed that rhVEGFR‑1 was only capable of binding to the full glycan form of rhVEGF‑165 and rhVEGF‑121. The dissociation constant for the binding of rhVEGFR‑1 to VEGF‑165, detected using Biacore, was 285 pM. In addition, rhVEGFR‑1 inhibited the proliferation and migration of human microvascular endothelial cells. In vivo experiments also demonstrated that rhVEGFR‑1 inhibited chicken chorioallantoic membrane neovascularization and angiogenesis in nude mice. In conclusion, an anti‑angiogenic recombinant soluble VEGFR was expressed (up to 5 mg/l) in CHO cells and was shown to be capable of inhibiting neovascularization in vivo and in vitro.

  13. Potent inhibition of human immunodeficiency virus by MDL 101028, a novel sulphonic acid polymer.

    PubMed

    Taylor, D L; Brennan, T M; Bridges, C G; Mullins, M J; Tyms, A S; Jackson, R; Cardin, A D

    1995-10-01

    MDL 101028, a novel biphenyl disulphonic acid urea co-polymer was designed and synthesised as a heparin mimetic. This low molecular weight polymer showed potent inhibition of human immunodeficiency virus type 1 (HIV-1) replication in a number of host-cell/virus systems, including primary clinical isolates of the virus cultured in human peripheral blood mononuclear cells (PBMCs). When compared with the heterogeneous polysulphated molecules, heparin and dextran sulphate, this chemically defined compound showed equivalent antiviral activity with 50% inhibitory concentrations (IC50s) in the range 0.27-3.0 micrograms/ml in the host-cell/virus systems tested. MDL 101028 also inhibited the replication of HIV type 2 and the simian immunodeficiency virus (SIV), as well as HIV-1 variants resistant to reverse transcriptase inhibitors. Virus growth was blocked when exposure of T-lymphocytes to MDL 101028 was restricted to the virus absorption stage, or even in whole blood conditions. MDL 101028 did not irreversibly inactivate virions, and in contrast to heparin, did not inhibit the attachment of radiolabelled HIV-1 to CD4+ T-cells. MDL 101028 blocked HIV-induced cell-to-cell fusion and this activity appears to explain the mechanism of its antiviral action. The antiviral evaluation of discrete oligomer molecules of MDL 101028 showed that a polymer chain length of six repeating units had optimal potency. The lack of anticoagulant properties and significant antiviral activity in whole blood may allow the development of MDL 101028 as a treatment of HIV infections.

  14. Organophosphorothionate pesticides inhibit the bioactivation of imipramine by human hepatic cytochrome P450s

    SciTech Connect

    Di Consiglio, Emma; Meneguz, Annarita; Testai, Emanuela . E-mail: testai@iss.it

    2005-06-15

    The drug-toxicant interaction between the antidepressant imipramine (IMI) and three organophosphorothionate pesticides (OPTs), to which humans may be chronically and simultaneously exposed, has been investigated in vitro. Concentrations of IMI (2-400 {mu}M) and OPTs ({<=}10 {mu}M) representative of actual human exposure have been tested with recombinant human CYPs and human liver microsomes (HLM). The different CYPs involved in IMI demethylation to the pharmacologically active metabolite desipramine (DES) were CYP2C19 > CYP1A2 > CYP3A4. The OPTs significantly inhibited (up to >80%) IMI bioactivation catalyzed by the recombinant CYPs tested, except CYP2D6, and by HLM; the inhibition was dose-dependent and started at low pesticide concentrations (0.25-2.5 {mu}M). The OPTs, having lower K {sub m} values, efficiently competed with IMI for the enzyme active site, as in the case of CYP2C19. However, with CYP1A2 and CYP3A4, a time- and NADPH-dependent mechanism-based inactivation also occurred, consistently with irreversible inhibition due to the release of the sulfur atom, binding to the active CYP during OPT desulfuration. At low IMI and OPT concentrations, lower IC50 values have been obtained with recombinant CYP1A2 (0.7-1.1 {mu}M) or with HLM rich in 1A2-related activity (2-10.8 {mu}M). The K {sub i} values (2-14 {mu}M), independent on substrate concentrations, were quite low and similar for the three pesticides. Exposure to OPTs during IMI therapeutic treatments may lead to decreased DES formation, resulting in high plasma levels of the parent drug, eventual impairment of its pharmacological action and possible onset of adverse drug reactions (ADRs)

  15. Nociceptin inhibits vanilloid TRPV-1-mediated neurosensitization induced by fenoterol in human isolated bronchi.

    PubMed

    Faisy, Christophe; Naline, Emmanuel; Rouget, Céline; Risse, Paul-André; Guerot, Emmanuel; Fagon, Jean-Yves; Chinet, Thierry; Roche, Nicolas; Advenier, Charles

    2004-09-01

    Chronic exposure to beta(2)-adrenoceptor agonists, especially fenoterol, has been shown to increase smooth muscle contraction to endothelin-1 in human bronchi partly through tachykinin-mediated pathways. The purpose of this work was to further investigate the role of sensory nerves in fenoterol-induced sensitization of human airways and the effect of nociceptin, a nociceptin/orphanin FQ (NOP) receptor agonist, on the increase in contraction after fenoterol exposure. Human bronchi from 62 patients were sensitized to endothelin-1 by prolonged incubation with fenoterol (0.1 microM, 15 h). The sensitizing effect of fenoterol was inhibited by high concentration of capsaicin (10 microM, 30 min before fenoterol sensitization), which induces depletion of mediators from sensory nerves, or co-incubation of fenoterol and capsazepine (1 microM), a vanilloid TRPV-1 receptor antagonist. Moreover, short pretreatment of bronchi with capsaicin (10 microM) or capsazepine (1 microM) after sensitization by fenoterol decreased the rise in smooth muscle contraction to endothelin-1. Nociceptin (1 microM) also inhibited the increased contraction in fenoterol-sensitized bronchi. Tertiapin (10 microM), an inhibitor of the inward-rectifier K(+) channels, but not naloxone (0.1 microM), a DOP/KOP/MOP receptor antagonist, prevented the inhibitory effect of nociceptin. In conclusion, fenoterol induces sensitization of human isolated bronchi to endothelin-1 in part through the stimulation of the vanilloid TRPV-1 receptor on tachykininergic sensory nerves. Nociceptin inhibits airway hyperresponsiveness via NOP receptor activation. This effect involves inward-rectifier K(+) channels.

  16. Common drugs inhibit human organic cation transporter 1 (OCT1)-mediated neurotransmitter uptake.

    PubMed

    Boxberger, Kelli H; Hagenbuch, Bruno; Lampe, Jed N

    2014-06-01

    The human organic cation transporter 1 (OCT1) is a polyspecific transporter involved in the uptake of positively charged and neutral small molecules in the liver. To date, few endogenous compounds have been identified as OCT1 substrates; more importantly, the effect of drugs on endogenous substrate transport has not been examined. In this study, we established monoamine neurotransmitters as substrates for OCT1, specifically characterizing serotonin transport in human embryonic kidney 293 cells. Kinetic analysis yielded a Km of 197 micomolar and a Vmax of 561 pmol/mg protein/minute for serotonin. Furthermore, we demonstrated that serotonin uptake was inhibited by diphenhydramine, fluoxetine, imatinib, and verapamil, with IC50 values in the low micromolar range. These results were recapitulated in primary human hepatocytes, suggesting that OCT1 plays a significant role in hepatic elimination of serotonin and that xenobiotics may alter the elimination of endogenous compounds as a result of interactions at the transporter level.

  17. Aloe-emodin inhibits proliferation of adult human keratinocytes in vitro.

    PubMed

    Popadic, Dusan; Savic, Emina; Ramic, Zorica; Djordjevic, Vladimir; Trajkovic, Vladimir; Medenica, Ljiljana; Popadic, Svetlana

    2012-01-01

    Aloe-emodin (AE) is a plant-derived hydroxyanthraquinone with several biological activities. It is present in a variety of skin-conditioning agents containing aloe extracts, but its influence on keratinocyte growth was not examined so far. We investigated the influence of AE on human keratinocyte proliferation and apoptosis in vitro. AE significantly inhibited proliferation of cultivated human keratinocytes at 5 μM concentration, as revealed by incorporation of radioactive thymidine. The antiproliferative effect of AE was accompanied with induction of apoptosis, but not necrosis, as demonstrated by flow cytometric analysis and lactate dehydrogenase release assay. Based on the half maximal inhibitory concentration values, we demonstrated that AE may impair proliferation of keratinocytes at concentrations far below the industry standards for commercial products containing aloe extracts. Therefore, further research of AE effects on the human skin and proper labeling of products are necessary for maximizing benefits from aloe extracts and to avoid undesired responses.

  18. Common Drugs Inhibit Human Organic Cation Transporter 1 (OCT1)-Mediated Neurotransmitter Uptake

    PubMed Central

    Boxberger, Kelli H.; Hagenbuch, Bruno

    2014-01-01

    The human organic cation transporter 1 (OCT1) is a polyspecific transporter involved in the uptake of positively charged and neutral small molecules in the liver. To date, few endogenous compounds have been identified as OCT1 substrates; more importantly, the effect of drugs on endogenous substrate transport has not been examined. In this study, we established monoamine neurotransmitters as substrates for OCT1, specifically characterizing serotonin transport in human embryonic kidney 293 cells. Kinetic analysis yielded a Km of 197 micomolar and a Vmax of 561 pmol/mg protein/minute for serotonin. Furthermore, we demonstrated that serotonin uptake was inhibited by diphenhydramine, fluoxetine, imatinib, and verapamil, with IC50 values in the low micromolar range. These results were recapitulated in primary human hepatocytes, suggesting that OCT1 plays a significant role in hepatic elimination of serotonin and that xenobiotics may alter the elimination of endogenous compounds as a result of interactions at the transporter level. PMID:24688079

  19. Ranolazine inhibits voltage-gated mechanosensitive sodium channels in human colon circular smooth muscle cells

    PubMed Central

    Neshatian, Leila; Strege, Peter R.; Rhee, Poong-Lyul; Kraichely, Robert E.; Mazzone, Amelia; Bernard, Cheryl E.; Cima, Robert R.; Larson, David W.; Dozois, Eric J.; Kline, Crystal F.; Mohler, Peter J.; Beyder, Arthur

    2015-01-01

    Human jejunum smooth muscle cells (SMCs) and interstitial cells of Cajal (ICCs) express the SCN5A-encoded voltage-gated, mechanosensitive sodium channel NaV1.5. NaV1.5 contributes to small bowel excitability, and NaV1.5 inhibitor ranolazine produces constipation by an unknown mechanism. We aimed to determine the presence and molecular identity of Na+ current in the human colon smooth muscle and to examine the effects of ranolazine on Na+ current, mechanosensitivity, and smooth muscle contractility. Inward currents were recorded by whole cell voltage clamp from freshly dissociated human colon SMCs at rest and with shear stress. SCN5A mRNA and NaV1.5 protein were examined by RT-PCR and Western blots, respectively. Ascending human colon strip contractility was examined in a muscle bath preparation. SCN5A mRNA and NaV1.5 protein were identified in human colon circular muscle. Freshly dissociated human colon SMCs had Na+ currents (−1.36 ± 0.36 pA/pF), shear stress increased Na+ peaks by 17.8 ± 1.8% and accelerated the time to peak activation by 0.7 ± 0.3 ms. Ranolazine (50 μM) blocked peak Na+ current by 43.2 ± 9.3% and inhibited shear sensitivity by 25.2 ± 3.2%. In human ascending colon strips, ranolazine decreased resting tension (31%), reduced the frequency of spontaneous events (68%), and decreased the response to smooth muscle electrical field stimulation (61%). In conclusion, SCN5A-encoded NaV1.5 is found in human colonic circular smooth muscle. Ranolazine blocks both peak amplitude and mechanosensitivity of Na+ current in human colon SMCs and decreases contractility of human colon muscle strips. Our data provide a likely mechanistic explanation for constipation induced by ranolazine. PMID:26185330

  20. P-gp activity and inhibition in the different regions of human intestine ex vivo.

    PubMed

    Li, Ming; de Graaf, Inge A M; de Jager, Marina H; Groothuis, Geny M M

    2017-03-01

    Although intestinal P-glycoprotein (P-gp) has been extensively studied in vitro and in animals, its activity and the consequences of P-gp inhibition for drug disposition and toxicity in humans are still difficult to accurately extrapolate from these studies. Moreover, existing in vitro models do not take into consideration that the intestine is heterogeneous with respect to P-gp expression. Recently, we reported rat precision-cut intestinal slices (PCIS) as a physiological ex vivo model to study the regional gradient of P-gp activity and inhibition. Here we extended the application of PCIS to the human intestine. For this purpose rhodamine 123 (R123) accumulation in the presence or absence of the P-gp inhibitors verapamil, cyclosporine A, quinidine, ketoconazole, PSC833 and CP100356 was measured in PCIS of human duodenum, jejunum, ileum and colon. R123 accumulation in the presence of the P-gp inhibitors appeared to be most enhanced in the ileum compared to the other regions. Moreover, the regional differences in accumulation are in line with published differences in abundance of P-gp. The rank order of the potency of the P-gp inhibitors, reflected by their IC50 , was comparable to that in rat PCIS. However, the increase in accumulation of the P-gp substrate R123 by the inhibitors was larger in human ileum PCIS than in rat PCIS, indicating species difference in P-gp abundance. These data show that human PCIS are an appropriate ex vivo model to study the activity of intestinal P-gp and predict the inhibitory effect of drugs and of transporter-mediated drug-drug interactions in the human intestine. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Plasmodium vivax Invasion of Human Erythrocytes Inhibited by Antibodies Directed against the Duffy Binding Protein

    PubMed Central

    Grimberg, Brian T; Udomsangpetch, Rachanee; Xainli, Jia; McHenry, Amy; Panichakul, Tasanee; Sattabongkot, Jetsumon; Cui, Liwang; Bockarie, Moses; Chitnis, Chetan; Adams, John; Zimmerman, Peter A; King, Christopher L

    2007-01-01

    Background Plasmodium vivax invasion requires interaction between the human Duffy antigen on the surface of erythrocytes and the P. vivax Duffy binding protein (PvDBP) expressed by the parasite. Given that Duffy-negative individuals are resistant and that Duffy-negative heterozygotes show reduced susceptibility to blood-stage infection, we hypothesized that antibodies directed against region two of P. vivax Duffy binding protein (PvDBPII) would inhibit P. vivax invasion of human erythrocytes. Methods and Findings Using a recombinant region two of the P. vivax Duffy binding protein (rPvDBPII), polyclonal antibodies were generated from immunized rabbits and affinity purified from the pooled sera of 14 P. vivax–exposed Papua New Guineans. It was determined by ELISA and by flow cytometry, respectively, that both rabbit and human antibodies inhibited binding of rPvDBPII to the Duffy antigen N-terminal region and to Duffy-positive human erythrocytes. Additionally, using immunofluorescent microscopy, the antibodies were shown to attach to native PvDBP on the apical end of the P. vivax merozoite. In vitro invasion assays, using blood isolates from individuals in the Mae Sot district of Thailand, showed that addition of rabbit anti-PvDBPII Ab or serum (antibodies against, or serum containing antibodies against, region two of the Plasmodium vivax Duffy binding protein) (1:100) reduced the number of parasite invasions by up to 64%, while pooled PvDBPII antisera from P. vivax–exposed people reduced P. vivax invasion by up to 54%. Conclusions These results show, for what we believe to be the first time, that both rabbit and human antibodies directed against PvDBPII reduce invasion efficiency of wild P. vivax isolated from infected patients, and suggest that a PvDBP-based vaccine may reduce human blood-stage P. vivax infection. PMID:18092885