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Sample records for regulatory cells inhibit

  1. Regulatory T cells inhibit CD34+ cell differentiation into NK cells by blocking their proliferation.

    PubMed

    Pedroza-Pacheco, Isabela; Shah, Divya; Domogala, Anna; Luevano, Martha; Blundell, Michael; Jackson, Nicola; Thrasher, Adrian; Madrigal, Alejandro; Saudemont, Aurore

    2016-01-01

    Graft versus Host Disease (GvHD) remains one of the main complications after hematopoietic stem cell transplantation (HSCT). Due to their ability to suppress effector cells, regulatory T cells (Tregs) have been proposed as a cellular therapy to prevent GvHD, however they also inhibit the functions of natural killer (NK) cells, key effectors of the Graft versus Leukemia effect. In this study, we have explored whether a Tregs therapy will also impact on NK cell differentiation. Using an in vitro model of hematopoietic stem cell (HSC) differentiation into NK cells, we found that activated Tregs led to a 90% reduction in NK cell numbers when added at the time of commitment to the NK cell lineage. This effect was contact dependent and was reversible upon Tregs depletion. The few NK cells that developed in these cultures were mature and exhibited normal functions. Furthermore, adoptive transfer of activated Tregs in rag(-/-) γc(-/-) mice abrogated HSC differentiation into NK cells thus confirming our in vitro findings. Collectively, these results demonstrate for the first time that activated Tregs can inhibit NK cell differentiation from HSC under specific conditions. PMID:26915707

  2. Regulatory T cells inhibit CD34+ cell differentiation into NK cells by blocking their proliferation

    PubMed Central

    Pedroza-Pacheco, Isabela; Shah, Divya; Domogala, Anna; Luevano, Martha; Blundell, Michael; Jackson, Nicola; Thrasher, Adrian; Madrigal, Alejandro; Saudemont, Aurore

    2016-01-01

    Graft versus Host Disease (GvHD) remains one of the main complications after hematopoietic stem cell transplantation (HSCT). Due to their ability to suppress effector cells, regulatory T cells (Tregs) have been proposed as a cellular therapy to prevent GvHD, however they also inhibit the functions of natural killer (NK) cells, key effectors of the Graft versus Leukemia effect. In this study, we have explored whether a Tregs therapy will also impact on NK cell differentiation. Using an in vitro model of hematopoietic stem cell (HSC) differentiation into NK cells, we found that activated Tregs led to a 90% reduction in NK cell numbers when added at the time of commitment to the NK cell lineage. This effect was contact dependent and was reversible upon Tregs depletion. The few NK cells that developed in these cultures were mature and exhibited normal functions. Furthermore, adoptive transfer of activated Tregs in rag-/- γc-/- mice abrogated HSC differentiation into NK cells thus confirming our in vitro findings. Collectively, these results demonstrate for the first time that activated Tregs can inhibit NK cell differentiation from HSC under specific conditions. PMID:26915707

  3. RARalpha is a regulatory factor for Am-80-induced cell growth inhibition of hematologic malignant cells.

    PubMed

    Jimi, Shiro; Mashima, Kota; Matsumoto, Taichi; Hara, Shuji; Suzumiya, Junji; Tamura, Kazuo

    2007-08-01

    Retinoids are used for treatment of acute promyelocytic leukemia (APL). Am-80, Tamibarotene, binds to retinoic acid receptor alpha (RARalpha) more specifically than all-trans retinoic acid. We studied the tumor cell suppressive effects of Am-80, with respect to cytotoxicity and growth inhibition using eight myeloid and lymphoid malignant cells in culture (HL-60, HL-60R, K-562, Kasumi-1, MEG01, Raji, U266B1, and U937). The effects of Am-80 were examined during 9 days of incubation with 10(-7)-10(-5) M of Am-80 in culture medium, which was changed every 3 days. HL-60 were the only cells sensitive to Am-80-induced cytotoxicity; the latter reached more than 95% after 9 days of incubation, and death was primarily through apoptosis. The total mass of RARalpha in HL-60 was significantly greater (p<0.006) than in ATRA-resistant HL-60 (HL-60R) as well as all of other cells tested. However, in all cells excluding HL-60, Am-80 induced time- and dose-dependent cell growth inhibition without noticeable cytotoxicity. TGF-beta2 was released into the media containing cells incubated with Am-80 for 3 days. A dose-dependent increment of phosphorylation of Smad-2 was also detected. The relative amount of secreted TGF-beta2 correlated with the growth inhibition rates in all cells tested excluding HL-60, and with the total mass of RARalpha in the cells (p=0.0137). Our results indicate that Am-80-induced cell-type non-specific growth inhibition is mediated by TGF-beta2, where the total mass of RARalpha could be an important regulatory factor in hematologic malignant cells. PMID:17611697

  4. Inhibition of cervical carcinoma cell line proliferation by the introduction of a bovine papillomavirus regulatory gene.

    PubMed Central

    Hwang, E S; Riese, D J; Settleman, J; Nilson, L A; Honig, J; Flynn, S; DiMaio, D

    1993-01-01

    Human papillomavirus (HPV) E6 and E7 oncogenes are expressed in the great majority of human cervical carcinomas, whereas the viral E2 regulatory gene is usually disrupted in these cancers. To investigate the roles of the papillomavirus E2 genes in the development and maintenance of cervical carcinoma, the bovine papillomavirus (BPV) E2 gene was acutely introduced into cervical carcinoma cell lines by infection with high-titer stocks of simian virus 40-based recombinant viruses. Expression of the BPV E2 protein in HeLa, C-4I, and MS751 cells results in specific inhibition of the expression of the resident HPV type 18 (HPV18) E6 and E7 genes and in inhibition of cell growth. HeLa cells, in which HPV gene expression is nearly completely abolished, undergo a dramatic and rapid inhibition of proliferation, which appears to be largely a consequence of a block in progression from the G1 to the S phase of the cell cycle. Loss of HPV18 gene expression in HeLa cells is also accompanied by a marked increase in the level of the cellular p53 tumor suppressor protein, apparently as a consequence of abrogation of HPV18 E6-mediated destabilization of p53. The proliferation of HT-3 cells, a human cervical carcinoma cell line devoid of detectable HPV DNA, is also inhibited by E2 expression, whereas two other epithelial cell lines that do not contain HPV DNA are not inhibited. Thus, a number of cervical carcinoma cell lines are remarkably sensitive to growth inhibition by the E2 protein. Although BPV E2-mediated inhibition of HPV18 E6 and E7 expression may contribute to growth inhibition in some of the cervical carcinoma cell lines, the BPV E2 protein also appears to exert a growth-inhibitory effect that is independent of its effects on HPV gene expression. Images PMID:8389903

  5. Comprehensive analysis of current approaches to inhibit regulatory T cells in cancer

    PubMed Central

    Pere, Helene; Tanchot, Corinne; Bayry, Jagadeesh; Terme, Magali; Taieb, Julien; Badoual, Cecile; Adotevi, Olivier; Merillon, Nathalie; Marcheteau, Elie; Quillien, Ve´ronique; Banissi, Claire; Carpentier, Alain; Sandoval, Federico; Nizard, Mevyn; Quintin-Colonna, Françoise; Kroemer, Guido; Fridman, Wolf H.; Zitvogel, Laurence; Oudard, Ste´phane; Tartour, Eric

    2012-01-01

    CD4+CD25+Foxp3+ regulatory T cells (Treg) have emerged as a dominant T cell population inhibiting anti-tumor effector T cells. Initial strategies used for Treg-depletion (cyclophosphamide, anti-CD25 mAb…) also targeted activated T cells, as they share many phenotypic markers. Current, ameliorated approaches to inhibit Treg aim to either block their function or their migration to lymph nodes and the tumor microenvironment. Various drugs originally developed for other therapeutic indications (anti-angiogenic molecules, tyrosine kinase inhibitors,etc) have recently been discovered to inhibit Treg. These approaches are expected to be rapidly translated to clinical applications for therapeutic use in combination with immunomodulators. PMID:22737608

  6. Nonspecific inhibition of alloantigen-induced proliferation by bone marrow natural regulatory cells

    SciTech Connect

    Dorshkind, K.; Rosse, C.

    1981-03-01

    We have previously reported that a lymphocyte-enriched fraction ofmurine bone marrow (BML) contains natural regulatory cells (NRC) that can inhibit in vitro proliferative and cytotoxic responses to alloantigens on a dose-dependent basis. In view of the potential importance of these cells to the outcome of bone marrow transplantation, we have undertaken a series of studies designed to inestigate the properties of the effector cell(s). Since clinical and experimental bone marrow transplantation is often performed by inoculating histoincompatible marrow into irradiated hosts, we have investigated the effects of irradiation on NRC and their ability to function across major and minor histocompatibility barriers. In this brief communication, we report that NRC can nonspecifically inhibit cellular immune responses across histocompatibility barriers and are not affected by high doses of irraddiation. In addition, we report that NRC are not T or B lymphocytes.

  7. Requirements for efficient cell-type proportioning: regulatory timescales, stochasticity and lateral inhibition.

    PubMed

    Pfeuty, B; Kaneko, K

    2016-01-01

    The proper functioning of multicellular organisms requires the robust establishment of precise proportions between distinct cell types. This developmental differentiation process typically involves intracellular regulatory and stochastic mechanisms to generate cell-fate diversity as well as intercellular signaling mechanisms to coordinate cell-fate decisions at tissue level. We thus surmise that key insights about the developmental regulation of cell-type proportion can be captured by the modeling study of clustering dynamics in population of inhibitory-coupled noisy bistable systems. This general class of dynamical system is shown to exhibit a very stable two-cluster state, but also metastability, collective oscillations or noise-induced state hopping, which can prevent from timely and reliably reaching a robust and well-proportioned clustered state. To circumvent these obstacles or to avoid fine-tuning, we highlight a general strategy based on dual-time positive feedback loops, such as mediated through transcriptional versus epigenetic mechanisms, which improves proportion regulation by coordinating early and flexible lineage priming with late and firm commitment. This result sheds new light on the respective and cooperative roles of multiple regulatory feedback, stochasticity and lateral inhibition in developmental dynamics. PMID:27172110

  8. Requirements for efficient cell-type proportioning: regulatory timescales, stochasticity and lateral inhibition

    NASA Astrophysics Data System (ADS)

    Pfeuty, B.; Kaneko, K.

    2016-04-01

    The proper functioning of multicellular organisms requires the robust establishment of precise proportions between distinct cell types. This developmental differentiation process typically involves intracellular regulatory and stochastic mechanisms to generate cell-fate diversity as well as intercellular signaling mechanisms to coordinate cell-fate decisions at tissue level. We thus surmise that key insights about the developmental regulation of cell-type proportion can be captured by the modeling study of clustering dynamics in population of inhibitory-coupled noisy bistable systems. This general class of dynamical system is shown to exhibit a very stable two-cluster state, but also metastability, collective oscillations or noise-induced state hopping, which can prevent from timely and reliably reaching a robust and well-proportioned clustered state. To circumvent these obstacles or to avoid fine-tuning, we highlight a general strategy based on dual-time positive feedback loops, such as mediated through transcriptional versus epigenetic mechanisms, which improves proportion regulation by coordinating early and flexible lineage priming with late and firm commitment. This result sheds new light on the respective and cooperative roles of multiple regulatory feedback, stochasticity and lateral inhibition in developmental dynamics.

  9. Regulatory T Cell Modulation by CBP/EP300 Bromodomain Inhibition.

    PubMed

    Ghosh, Srimoyee; Taylor, Alexander; Chin, Melissa; Huang, Hon-Ren; Conery, Andrew R; Mertz, Jennifer A; Salmeron, Andres; Dakle, Pranal J; Mele, Deanna; Cote, Alexandre; Jayaram, Hari; Setser, Jeremy W; Poy, Florence; Hatzivassiliou, Georgia; DeAlmeida-Nagata, Denise; Sandy, Peter; Hatton, Charlie; Romero, F Anthony; Chiang, Eugene; Reimer, Thornik; Crawford, Terry; Pardo, Eneida; Watson, Venita G; Tsui, Vickie; Cochran, Andrea G; Zawadzke, Laura; Harmange, Jean-Christophe; Audia, James E; Bryant, Barbara M; Cummings, Richard T; Magnuson, Steven R; Grogan, Jane L; Bellon, Steve F; Albrecht, Brian K; Sims, Robert J; Lora, Jose M

    2016-06-17

    Covalent modification of histones is a fundamental mechanism of regulated gene expression in eukaryotes, and interpretation of histone modifications is an essential feature of epigenetic control. Bromodomains are specialized binding modules that interact with acetylated histones, linking chromatin recognition to gene transcription. Because of their ability to function in a domain-specific fashion, selective disruption of bromodomain:acetylated histone interactions with chemical probes serves as a powerful means for understanding biological processes regulated by these chromatin adaptors. Here we describe the discovery and characterization of potent and selective small molecule inhibitors for the bromodomains of CREBBP/EP300 that engage their target in cellular assays. We use these tools to demonstrate a critical role for CREBBP/EP300 bromodomains in regulatory T cell biology. Because regulatory T cell recruitment to tumors is a major mechanism of immune evasion by cancer cells, our data highlight the importance of CREBBP/EP300 bromodomain inhibition as a novel, small molecule-based approach for cancer immunotherapy. PMID:27056325

  10. Selective inhibition of regulatory T cells by targeting the PI3K-Akt pathway.

    PubMed

    Abu-Eid, Rasha; Samara, Raed N; Ozbun, Laurent; Abdalla, Maher Y; Berzofsky, Jay A; Friedman, Kevin M; Mkrtichyan, Mikayel; Khleif, Samir N

    2014-11-01

    Despite the strides that immunotherapy has made in mediating tumor regression, the clinical effects are often transient, and therefore more durable responses are still needed. The temporary nature of the therapy-induced immune response can be attributed to tumor immune evasion mechanisms, mainly the effect of suppressive immune cells and, in particular, regulatory T cells (Treg). Although the depletion of Tregs has been shown to be effective in enhancing immune responses, selective depletion of these suppressive cells without affecting other immune cells has not been very successful, and new agents are sought. We found that PI3K-Akt pathway inhibitors selectively inhibit Tregs with minimal effect on conventional T cells (Tconv). Our results clearly show selective in vitro inhibition of activation (as represented by a decrease in downstream signaling) and proliferation of Tregs in comparison with Tconvs when treated with different Akt and PI3K inhibitors. This effect has been observed in both human and murine CD4 T cells. In vivo treatment with these inhibitors resulted in a significant and selective reduction in Tregs in both naïve and tumor-bearing mice. Furthermore, these PI3K-Akt inhibitors led to a significant therapeutic antitumor effect, which was shown to be Treg dependent. Here, we report the use of PI3K-Akt pathway inhibitors as potent agents for the selective depletion of suppressive Tregs. We show that these inhibitors are able to enhance the antitumor immune response and are therefore promising clinical reagents for Treg depletion. PMID:25080445

  11. Selective inhibition of regulatory T cells by targeting PI3K-Akt pathway

    PubMed Central

    Abu-Eid, R; Samara, RN; Ozbun, L; Abdalla, MY; Berzofsky, JA; Friedman, KM; Mkrtichyan, M; Khleif, SN

    2014-01-01

    Despite the strides that immunotherapy has made in mediating tumor regression, the clinical effects are often transient, and therefore more durable responses still are needed. The temporary nature of the therapy-induced immune response can be attributed to tumor immune evasion mechanisms, mainly the effect of suppressive immune cells and, in particular, T regulatory cells (Treg). Although the depletion of Treg has been shown to be effective in enhancing immune responses, selective depletion of these suppressive cells without affecting other immune cells has not been very successful, and new agents are sought. We found that PI3K-Akt pathway inhibitors selectively inhibit Treg with minimal effect on conventional T cells (Tconv). Our results clearly show selective in vitro inhibition of activation (as represented by a decrease in downstream signaling) and proliferation of Treg in comparison to Tconv when treated with different Akt and PI3K inhibitors. This effect has been observed in both human and murine CD4 T cells. In vivo treatment with these inhibitors resulted in a significant and selective reduction in Treg both in naïve and tumor-bearing mice. Furthermore, these PI3K-Akt inhibitors led to a significant therapeutic antitumor effect, which was shown to be Treg-dependent. Here, we report the use of PI3K-Akt pathway inhibitors as potent agents for the selective depletion of suppressive Treg. We show that these inhibitors are able to enhance the antitumor immune response and are therefore promising clinical reagents for Treg-depletion. PMID:25080445

  12. CTLA4Ig inhibits effector T cells through regulatory T cells and TGFβ1

    PubMed Central

    Deppong, Christine M.; Bricker, Traci L.; Rannals, Brandy D.; Van Rooijen, Nico; Hsieh, Chyi-Song; Green, Jonathan M.

    2013-01-01

    The CD28 costimulatory receptor is a critical regulator of T cell function making it an attractive therapeutic target for the treatment of immune mediated diseases. CTLA4Ig, now approved for use in humans, prevents naive T cell activation by binding to B7-proteins and blocking engagement of CD28. However, CTLA4Ig suppresses inflammation even if administered when disease is established, suggesting alternative mechanisms. We identified a novel, CD28-independent mechanism by which CTLA4Ig inhibits activated T cells. We show that in vitro, CTLA4Ig synergizes with nitric oxide from bone marrow derived macrophages to inhibit T cell proliferation. Depletion of Tregs or interference with TGFβ signaling abrogated the inhibitory effect of CTLA4Ig. Parallel in vivo experiments using an allergic airway inflammation model demonstrated that this novel mechanism required both macrophages andTregs. Furthermore, CTLA4Ig was ineffective in SMAD3-deficient mice, supporting a requirement for TGFβ signaling. Thus, in addition to preventing naïve T cells from being fully activated, CTLA4Ig can turn off already activated effector T cells by an NO/Treg/TGFβ-dependent pathway. This mechanism is similar to cell extrinsic effects of endogenous CTLA-4 and may be particularly important in the ability of CTLA4Ig to treat chronic inflammatory disease. PMID:23956428

  13. Oral tolerance to cancer can be abrogated by T regulatory cell inhibition.

    PubMed

    Whelan, Maria C; Casey, Garrett; Larkin, John O; Guinn, Barbara-ann; O'Sullivan, Gerald C; Tangney, Mark

    2014-01-01

    Oral administration of tumour cells induces an immune hypo-responsiveness known as oral tolerance. We have previously shown that oral tolerance to a cancer is tumour antigen specific, non-cross-reactive and confers a tumour growth advantage. We investigated the utilisation of regulatory T cell (Treg) depletion on oral tolerance to a cancer and its ability to control tumour growth. Balb/C mice were gavage fed homogenised tumour tissue--JBS fibrosarcoma (to induce oral tolerance to a cancer), or PBS as control. Growth of subcutaneous JBS tumours were measured; splenic tissue excised and flow cytometry used to quantify and compare systemic Tregs and T effector (Teff) cell populations. Prior to and/or following tumour feeding, mice were intraperitoneally administered anti-CD25, to inactivate systemic Tregs, or given isotype antibody as a control. Mice which were orally tolerised prior to subcutaneous tumour induction, displayed significantly higher systemic Treg levels (14% vs 6%) and faster tumour growth rates than controls (p<0.05). Complete regression of tumours were only seen after Treg inactivation and occurred in all groups--this was not inhibited by tumour feeding. The cure rates for Treg inactivation were 60% during tolerisation, 75% during tumour growth and 100% during inactivation for both tolerisation and tumour growth. Depletion of Tregs gave rise to an increased number of Teff cells. Treg depletion post-tolerisation and post-tumour induction led to the complete regression of all tumours on tumour bearing mice. Oral administration of tumour tissue, confers a tumour growth advantage and is accompanied by an increase in systemic Treg levels. The administration of anti-CD25 Ab decreased Treg numbers and caused an increase in Teffs. Most notably Treg cell inhibition overcame established oral tolerance with consequent tumor regression, especially relevant to foregut cancers where oral tolerance is likely to be induced by the shedding of tumour tissue into the

  14. Regulatory T Cell DNA Methyltransferase Inhibition Accelerates Resolution of Lung Inflammation

    PubMed Central

    Singer, Benjamin D.; Mock, Jason R.; Aggarwal, Neil R.; Garibaldi, Brian T.; Sidhaye, Venkataramana K.; Florez, Marcus A.; Chau, Eric; Gibbs, Kevin W.; Mandke, Pooja; Tripathi, Ashutosh; Yegnasubramanian, Srinivasan; King, Landon S.

    2015-01-01

    Acute respiratory distress syndrome (ARDS) is a common and often fatal inflammatory lung condition without effective targeted therapies. Regulatory T cells (Tregs) resolve lung inflammation, but mechanisms that enhance Tregs to promote resolution of established damage remain unknown. DNA demethylation at the forkhead box protein 3 (Foxp3) locus and other key Treg loci typify the Treg lineage. To test how dynamic DNA demethylation affects lung injury resolution, we administered the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (DAC) to wild-type (WT) mice beginning 24 hours after intratracheal LPS-induced lung injury. Mice that received DAC exhibited accelerated resolution of their injury. Lung CD4+CD25hiFoxp3+ Tregs from DAC-treated WT mice increased in number and displayed enhanced Foxp3 expression, activation state, suppressive phenotype, and proliferative capacity. Lymphocyte-deficient recombinase activating gene-1–null mice and Treg-depleted (diphtheria toxin-treated Foxp3DTR) mice did not resolve their injury in response to DAC. Adoptive transfer of 2 × 105 DAC-treated, but not vehicle-treated, exogenous Tregs rescued Treg-deficient mice from ongoing lung inflammation. In addition, in WT mice with influenza-induced lung inflammation, DAC rescue treatment facilitated recovery of their injury and promoted an increase in lung Treg number. Thus, DNA methyltransferase inhibition, at least in part, augments Treg number and function to accelerate repair of experimental lung injury. Epigenetic pathways represent novel manipulable targets for the treatment of ARDS. PMID:25295995

  15. YY1 inhibits differentiation and function of regulatory T cells by blocking Foxp3 expression and activity

    PubMed Central

    Hwang, Soo Seok; Jang, Sung Woong; Kim, Min Kyung; Kim, Lark Kyun; Kim, Bong-Sung; Kim, Hyeong Su; Kim, Kiwan; Lee, Wonyong; Flavell, Richard A.; Lee, Gap Ryol

    2016-01-01

    Regulatory T (Treg) cells are essential for maintenance of immune homeostasis. Foxp3 is the key transcription factor for Treg-cell differentiation and function; however, molecular mechanisms for its negative regulation are poorly understood. Here we show that YY1 expression is lower in Treg cells than Tconv cells, and its overexpression causes a marked reduction of Foxp3 expression and abrogation of suppressive function of Treg cells. YY1 is increased in Treg cells under inflammatory conditions with concomitant decrease of suppressor activity in dextran sulfate-induced colitis model. YY1 inhibits Smad3/4 binding to and chromatin remodelling of the Foxp3 locus. In addition, YY1 interrupts Foxp3-dependent target gene expression by physically interacting with Foxp3 and by directly binding to the Foxp3 target genes. Thus, YY1 inhibits differentiation and function of Treg cells by blocking Foxp3. PMID:26892542

  16. YY1 inhibits differentiation and function of regulatory T cells by blocking Foxp3 expression and activity.

    PubMed

    Hwang, Soo Seok; Jang, Sung Woong; Kim, Min Kyung; Kim, Lark Kyun; Kim, Bong-Sung; Kim, Hyeong Su; Kim, Kiwan; Lee, Wonyong; Flavell, Richard A; Lee, Gap Ryol

    2016-01-01

    Regulatory T (T(reg)) cells are essential for maintenance of immune homeostasis. Foxp3 is the key transcription factor for T(reg)-cell differentiation and function; however, molecular mechanisms for its negative regulation are poorly understood. Here we show that YY1 expression is lower in T(reg) cells than T(conv) cells, and its overexpression causes a marked reduction of Foxp3 expression and abrogation of suppressive function of Treg cells. YY1 is increased in T(reg) cells under inflammatory conditions with concomitant decrease of suppressor activity in dextran sulfate-induced colitis model. YY1 inhibits Smad3/4 binding to and chromatin remodelling of the Foxp3 locus. In addition, YY1 interrupts Foxp3-dependent target gene expression by physically interacting with Foxp3 and by directly binding to the Foxp3 target genes. Thus, YY1 inhibits differentiation and function of T(reg) cells by blocking Foxp3. PMID:26892542

  17. Platelet microparticles inhibit IL-17 production by regulatory T cells through P-selectin.

    PubMed

    Dinkla, Sip; van Cranenbroek, Bram; van der Heijden, Wouter A; He, Xuehui; Wallbrecher, Rike; Dumitriu, Ingrid E; van der Ven, André J; Bosman, Giel J C G M; Koenen, Hans J P M; Joosten, Irma

    2016-04-21

    Self-tolerance and immune homeostasis are orchestrated by FOXP3(+)regulatory T cells (Tregs). Recent data have revealed that upon stimulation, Tregs may exhibit plasticity toward a proinflammatory phenotype, producing interleukin 17 (IL-17) and/or interferon γ (IFN-γ). Such deregulation of Tregs may contribute to the perpetuation of inflammatory processes, including graft-versus-host disease. Thus, it is important to identify immunomodulatory factors influencing Treg stability. Platelet-derived microparticles (PMPs) are involved in hemostasis and vascular health and have recently been shown to be intimately involved in (pathogenic) immune responses. Therefore, we investigated whether PMPs have the ability to affect Treg plasticity. PMPs were cocultured with healthy donor peripheral blood-derived Tregs that were stimulated with anti-CD3/CD28 monoclonal antibodies in the presence of IL-2, IL-15, and IL-1β. PMPs prevented the differentiation of peripheral blood-derived Tregs into IL-17- and IFN-γ-producing cells, even in the presence of the IL-17-driving proinflammatory cytokine IL-1β. The mechanism of action by which PMPs prevent Treg plasticity consisted of rapid and selective P-selectin-dependent binding of PMPs to a CCR6(+)HLA-DR(+)memory-like Treg subset and their ability to inhibit Treg proliferation, in part through CXCR3 engagement. The findings that ∼8% of Tregs in the circulation of healthy individuals are CD41(+)P-selectin(+)and that distinct binding of patient plasma PMPs to Tregs was observed support in vivo relevance. These findings open the exciting possibility that PMPs actively regulate the immune response at sites of (vascular) inflammation, where they are known to accumulate and interact with leukocytes, consolidating the (vascular) healing process. PMID:26903549

  18. Antigen targeting to dendritic cells combined with transient regulatory T cell inhibition results in long-term tumor regression

    PubMed Central

    Unger, Wendy WJ; Mayer, Christian T; Engels, Steef; Hesse, Christina; Perdicchio, Maurizio; Puttur, Franz; Streng-Ouwehand, Ingeborg; Litjens, Manja; Kalay, Hakan; Berod, Luciana; Sparwasser, Tim; van Kooyk, Yvette

    2014-01-01

    Therapeutic vaccinations against cancer are still largely ineffective. Major caveats are inefficient delivery of tumor antigens to dendritic cells (DCs) and excessive immune suppression by Foxp3+ regulatory T cells (Tregs), resulting in defective T cell priming and failure to induce tumor regression. To circumvent these problems we evaluated a novel combinatorial therapeutic strategy. We show that tumor antigen targeting to DC-SIGN in humanized hSIGN mice via glycans or specific antibodies induces superior T cell priming. Next, this targeted therapy was combined with transient Foxp3+ Treg depletion employing hSIGNxDEREG mice. While Treg depletion alone slightly delayed B16-OVA melanoma growth, only the combination therapy instigated long-term tumor regression in a substantial fraction of mice. This novel strategy resulted in optimal generation of antigen-specific activated CD8+ T cells which accumulated in regressing tumors. Notably, Treg depletion also allowed the local appearance of effector T cells specific for endogenous B16 antigens. This indicates that antitumor immune responses can be broadened by therapies aimed at controlling Tregs in tumor environments. Thus, transient inhibition of Treg-mediated immune suppression potentiates DC targeted antigen vaccination and tumor-specific immunity. PMID:26405564

  19. Regulatory T cells prevent CD8 T cell maturation by inhibiting CD4 Th cells at tumor sites.

    PubMed

    Chaput, Nathalie; Darrasse-Jèze, Guillaume; Bergot, Anne-Sophie; Cordier, Corinne; Ngo-Abdalla, Stacie; Klatzmann, David; Azogui, Orly

    2007-10-15

    Natural regulatory T cells (Tregs) are present in high frequencies among tumor-infiltrating lymphocytes and in draining lymph nodes, supposedly facilitating tumor development. To investigate their role in controlling local immune responses, we analyzed intratumoral T cell accumulation and function in the presence or absence of Tregs. Tumors that grew in normal BALB/c mice injected with the 4T1 tumor cell line were highly infiltrated by Tregs, CD4 and CD8 cells, all having unique characteristics. Most infiltrating Tregs expressed low levels of CD25Rs and Foxp3. They did not proliferate even in the presence of IL-2 but maintained a strong suppressor activity. CD4 T cells were profoundly anergic and CD8 T cell proliferation and cytotoxicity were severely impaired. Depletion of Tregs modified the characteristics of tumor infiltrates. Tumors were initially invaded by activated CD4(+)CD25(-) T cells, which produced IL-2 and IFN-gamma. This was followed by the recruitment of highly cytotoxic CD8(+) T cells at tumor sites leading to tumor rejection. The beneficial effect of Treg depletion in tumor regression was abrogated when CD4 helper cells were also depleted. These findings indicate that the massive infiltration of tumors by Tregs prevents the development of a successful helper response. The Tregs in our model prevent Th cell activation and subsequent development of efficient CD8 T cell activity required for the control of tumor growth. PMID:17911581

  20. Epirubicin, Identified Using a Novel Luciferase Reporter Assay for Foxp3 Inhibitors, Inhibits Regulatory T Cell Activity

    PubMed Central

    Kashima, Hajime; Momose, Fumiyasu; Umehara, Hiroshi; Miyoshi, Nao; Ogo, Naohisa; Muraoka, Daisuke; Shiku, Hiroshi; Harada, Naozumi; Asai, Akira

    2016-01-01

    Forkhead box protein p3 (Foxp3) is crucial to the development and suppressor function of regulatory T cells (Tregs) that have a significant role in tumor-associated immune suppression. Development of small molecule inhibitors of Foxp3 function is therefore considered a promising strategy to enhance anti-tumor immunity. In this study, we developed a novel cell-based assay system in which the NF-κB luciferase reporter signal is suppressed by the co-expressed Foxp3 protein. Using this system, we screened our chemical library consisting of approximately 2,100 compounds and discovered that a cancer chemotherapeutic drug epirubicin restored the Foxp3-inhibited NF-κB activity in a concentration-dependent manner without influencing cell viability. Using immunoprecipitation assay in a Treg-like cell line Karpas-299, we found that epirubicin inhibited the interaction between Foxp3 and p65. In addition, epirubicin inhibited the suppressor function of murine Tregs and thereby improved effector T cell stimulation in vitro. Administration of low dose epirubicin into tumor-bearing mice modulated the function of immune cells at the tumor site and promoted their IFN-γ production without direct cytotoxicity. In summary, we identified the novel action of epirubicin as a Foxp3 inhibitor using a newly established luciferase-based cellular screen. Our work also demonstrated our screen system is useful in accelerating discovery of Foxp3 inhibitors. PMID:27284967

  1. The immune tolerance of cancer is mediated by IDO that is inhibited by COX-2 inhibitors through regulatory T cells.

    PubMed

    Lee, Sung Yong; Choi, Hye Kyoung; Lee, Kyoung Ju; Jung, Jin Yong; Hur, Gyu Young; Jung, Ki Hwan; Kim, Je Hyeong; Shin, Chol; Shim, Jae Jeong; In, Kwang Ho; Kang, Kyung Ho; Yoo, Se Hwa

    2009-01-01

    Prostaglandin (PGE2), synthesized by cyclooxygenase-2 (COX-2), is associated with cellular immune tolerance during the process of cancer development. Induction of tolerance requires a specific environment in which dendritic cells and regulatory T cells (Tregs) play an essential role. It was recently shown that maturation of dendritic cells in the presence of indoleamine 2, 3-dioxygenase (IDO) results in activation of Tregs, and inhibition of COX-2 activity regulated IDO expression within the tumor microenvironment. Thus, we hypothesized that the tumor immune tolerance would be inhibited by COX-2 inhibitor and this inhibition would be mediated by IDO-dependent Tregs inhibition. The PGE2 in Lewis lung cancer cells (3LL) and serum of mice were measured for the evaluation of COX-2 inhibitors' local and systemic effects. The production of PGE2 in 3LL cells and serum of 3LL tumor-bearing mice were decreased by COX-2 inhibition. However, there were no significant differences in serum PGE2 levels among normal control and celecoxib-treated nontumor-bearing mice. The accumulation of Tregs was reduced in the celecoxib-treated 3LL tumor-bearing mice. In addition, the expressions of COX-2, IDO, and Foxp3 were reduced in the mice treated with a COX-2 inhibitor, and this was found to correlate with a reduction in the size of tumor mass and metastasis. These results suggest that the antitumor effects of COX-2 inhibitors seemed to be correlated with the inhibition of IDO and Tregs. Therefore, COX-2 inhibitors might provide a therapeutic strategy for Tregs-induced tumor immune tolerance. PMID:19307990

  2. Inhibition of breast cancer metastasis by resveratrol-mediated inactivation of tumor-evoked regulatory B cells

    PubMed Central

    Lee-Chang, Catalina; Bodogai, Monica; Martin-Montalvo, Alejandro; Wejksza, Katarzyna; Sanghvi, Mitesh; Moaddel, Ruin; de Cabo, Rafael; Biragyn, Arya

    2013-01-01

    We previously reported that tumor-evoked regulatory B cells (tBregs) play an essential role in breast cancer lung metastasis by inducing TGFβ-dependent conversion of metastasis-promoting FoxP3+ Tregs. Here we show that resveratrol (RSV), a plant-derived polyphenol, at low and non-cytotoxic doses for immune cells can efficiently inhibit lung metastasis in mice. The mechanism of this process is that RSV inactivates Stat3 preventing the generation and function of tBregs, including expression of TGFβ. As a result, it frees antitumor effector immune responses by disabling tBreg-induced conversion of FoxP3+ Tregs. We propose that RSV at low doses may also benefit humans to control cancer escape-promoting tBreg/Tregs without non-specific inactivation of effector immune cells. PMID:24043896

  3. Algal sulfated carrageenan inhibits proliferation of MDA-MB-231 cells via apoptosis regulatory genes.

    PubMed

    Murad, Hossam; Ghannam, Ahmed; Al-Ktaifani, Mahmoud; Abbas, Assef; Hawat, Mohammad

    2015-03-01

    Marine algae are prolific sources of sulfated polysaccharides, which may explain the low incidence of certain cancers in countries that traditionally consume marine food. Breast cancer is one of the most common types of non‑skin cancer in females. In this study, extracted sulfated carrageenan (ESC), predominantly consisting of ι‑carrageenan extracted from the red alga Laurencia papillosa, was characterized using Fourier transform infrared spectrometry. The biological effects of the identified extract were investigated and its potential cytotoxic activity was tested against the MDA‑MB‑231 cancer cell line. The biological biometer of the inhibitory concentration of the polysaccharide‑treated MDA‑MB‑231 cells was determined as 50 µM. Treatment with 50 µM ESC inhibited cell proliferation and promptly induced cell death through nuclear condensation and DNA fragmentation. Characterization of polysaccharide‑treated MDA‑MB‑231 cell death revealed that induction of apoptosis occurred via the activation of the extrinsic apoptotic caspase‑8 gene. The apoptotic signaling pathway was regulated through caspase‑3, caspase‑9, p53, Bax and Bcl‑2 genes. These findings suggest that ESC may serve as a potential therapeutic agent to target breast cancer via prompting apoptosis. PMID:25384757

  4. Schisandrin B inhibits Th1/Th17 differentiation and promotes regulatory T cell expansion in mouse lymphocytes.

    PubMed

    Chen, Zhaoyang; Guo, Min; Song, Guohua; Gao, Jiping; Zhang, Yinhong; Jing, Zhijie; Liu, Tianfu; Dong, Chuan

    2016-06-01

    Schisandrin B (Sch-B), the most abundant active ingredient of the fruit of Schisandra chinensis, has been proposed to have antioxidant, anti-tumor and anti-inflammatory effects. The present study was undertaken to investigate the effect of Sch-B on differentiation of T helper cells (Th). Using mouse splenic lymphocytes stimulated with concanavalin A (Con A) in vitro and ex vivo as inflammation models, we found that Sch-B significantly inhibited secretion of Th1 and Th17 related cytokines, such as IFN-γ and IL-17. In addition, we found that Sch-B suppressed the differentiation of naive CD4+ T cells into Th1 and Th17 cells, while promoted their differentiation into the regulatory T cells (Treg) in vitro. We further found that Sch-B suppressed transcription of Th1-related T-box transcription factor, T-bet, and Th17-related transcription factor, retinoid related orphan receptor gamma t (RORγt), while enhanced transcription of Treg-related transcription factor forkhead box protein 3 (Foxp3) in naive CD4+ T cells under Th cell polarization conditions. Furthermore, the effect of Sch-B on the T cell differentiation was abrogated by heme oxygenase-1 (HO-1) inhibitor zinc protoporphyrin. Taken together, we conclude that Sch-B can modulate differentiation of naïve CD4+ T cells into specific lineages of effector cells, which may have potential benefits for treatment of autoimmune diseases. PMID:27085037

  5. Transforming growth factor-beta1 inhibits tissue engineering cartilage absorption via inducing the generation of regulatory T cells.

    PubMed

    Li, Chichi; Bi, Wei; Gong, Yiming; Ding, Xiaojun; Guo, Xuehua; Sun, Jian; Cui, Lei; Yu, Youcheng

    2016-02-01

    The objective of the present study was to explore the mechanisms of transforming growth factor (TGF)-β1 inhibiting the absorption of tissue engineering cartilage. We transfected TGF-β1 gene into bone marrow mesenchymal stem cells (BMMSCs) and co-cultured with interferon (IFN)-γ and tumour necrosis factor (TNF)-α and CD4(+) CD25(-) T lymphocytes. We then characterized the morphological changes, apoptosis and characterization of chondrogenic-committed cells from TGF-β1(+) BMMSCs and explored their mechanisms. Results showed that BMMSCs apoptosis and tissue engineering cartilage absorption in the group with added IFN-γ and TNF-α were greater than in the control group. In contrast, there was little BMMSC apoptosis and absorption by tissue engineering cartilage in the group with added CD4(+) CD25(-) T lymphocytes; Foxp3(+) T cells and CD25(+) CD39(+) T cells were found. In contrast, no type II collagen or Foxp3(+) T cells or CD25(+) CD39(+) T cells was found in the TGF-β1(-) BMMSC group. The data suggest that IFN-γ and TNF-α induced BMMSCs apoptosis and absorption of tissue engineering cartilage, but the newborn regulatory T (Treg) cells inhibited the function of IFN-γ and TNF-α and protected BMMSCs and tissue engineering cartilage. TGF-β1not only played a cartilage inductive role, but also inhibited the absorption of tissue engineering cartilage. The pathway proposed in our study may simulate the actual reaction procedure after implantation of BMMSCs and tissue engineering cartilage in vivo. PMID:23868873

  6. Methionine Enkephalin (MENK) Inhibits tumor growth through regulating CD4+Foxp3+ Regulatory T cells (Tregs) in mice

    PubMed Central

    Li, Xuan; Meng, Yiming; Plotnikoff, Nicolas P; Youkilis, Gene; Griffin, Noreen; Wang, Enhua; Lu, Changlong; Shan, Fengping

    2015-01-01

    Methionine enkephalin (MENK), an endogenous neuropeptide, plays an crucial role in both neuroendocrine and immune systems. CD4+Foxp3+ regulatory T cells (Tregs) are identified as a major subpopulation of T lymphocytes in suppressing immune system to keep balanced immunity. The aim of this research work was to elucidate the mechanisms via which MENK interacts with Tregs in cancer situation. The influence of MENK on transforming growth factor-β (TGF-β) mediated conversion from naïve CD4+CD25- T cells to CD4+CD25+ Tregs was determined and the data from flow cytometry (FCM) analysis indicated that MENK effectively inhibited the expression of Foxp3 during the process of TGF-βinduction. Furthermore, this inhibiting process was accompanied by diminishing phosphorylation and nuclear translocation of Smad2/3, confirmed by western blot (WB) analysis and immunofluorescence (IF) at molecular level. We established sarcoma mice model with S180 to investigate whether MENK could modulate Tregs in tumor circumstance. Our findings showed that MENK delayed the development of tumor in S180 tumor bearing mice and down-regulated level of Tregs. Together, these novel findings reached a conclusion that MENK could inhibit Tregs activity directly and retard tumor development through down-regulating Tregs in mice. This work advances the deepening understanding of the influence of MENK on Tregs in cancer situation, and relation of MENK with immune system, supporting the implication of MENK as a new strategy for cancer immunotherapy. PMID:25701137

  7. CD56brightCD16- NK Cells Produce Adenosine through a CD38-Mediated Pathway and Act as Regulatory Cells Inhibiting Autologous CD4+ T Cell Proliferation.

    PubMed

    Morandi, Fabio; Horenstein, Alberto L; Chillemi, Antonella; Quarona, Valeria; Chiesa, Sabrina; Imperatori, Andrea; Zanellato, Silvia; Mortara, Lorenzo; Gattorno, Marco; Pistoia, Vito; Malavasi, Fabio

    2015-08-01

    Recent studies suggested that human CD56(bright)CD16(-) NK cells may play a role in the regulation of the immune response. Since the mechanism(s) involved have not yet been elucidated, in the present study we have investigated the role of nucleotide-metabolizing enzymes that regulate the extracellular balance of nucleotides/nucleosides and produce the immunosuppressive molecule adenosine (ADO). Peripheral blood CD56(dim)CD16(+) and CD56(bright)CD16(-) NK cells expressed similar levels of CD38. CD39, CD73, and CD157 expression was higher in CD56(bright)CD16(-) than in CD56(dim)CD16(+) NK cells. CD57 was mostly expressed by CD56(dim)CD16(+) NK cells. CD203a/PC-1 expression was restricted to CD56(bright)CD16(-) NK cells. CD56(bright)CD16(-) NK cells produce ADO and inhibit autologous CD4(+) T cell proliferation. Such inhibition was 1) reverted pretreating CD56(bright)CD16(-) NK cells with a CD38 inhibitor and 2) increased pretreating CD56(bright)CD16(-) NK cells with a nucleoside transporter inhibitor, which increase extracellular ADO concentration. CD56(bright)CD16(-) NK cells isolated from the synovial fluid of juvenile idiopathic arthritis patients failed to inhibit autologous CD4(+) T cell proliferation. Such functional impairment could be related to 1) the observed reduced CD38/CD73 expression, 2) a peculiar ADO production kinetics, and 3) a different expression of ADO receptors. In contrast, CD56(bright)CD16(-) NK cells isolated from inflammatory pleural effusions display a potent regulatory activity. In conclusion, CD56(bright)CD16(-) NK cells act as "regulatory cells" through ADO produced by an ectoenzymes network, with a pivotal role of CD38. This function may be relevant for the modulation of the immune response in physiological and pathological conditions, and it could be impaired during autoimmune/inflammatory diseases. PMID:26091716

  8. In vivo inhibition of human CD19 targeted effector T cells by natural T regulatory cells in a xenotransplant murine model of B cell malignancy

    PubMed Central

    Lee, James; Hayman, Erik; Pegram, Hollie; Santos, Elmer; Heller, Glen; Sadelain, Michel; Brentjens, Renier J.

    2011-01-01

    Human T cells genetically modified to express chimeric antigen receptors (CARs) specific to the B cell tumor antigen CD19 can successfully eradicate systemic human CD19+ tumors in immunocompromised SCID-Beige mice. However, in the clinical setting, CD4+ CD25hi T regulatory cells (Tregs) present within the tumor microenvironment are potent suppressors of tumor-targeted effector T cells. In order to assess the impact of Tregs on CAR-modified T cells in the SCID-Beige xenotransplant model, we isolated, genetically targeted and expanded natural T regulatory cells (nTregs). In vitro, nTregs, modified to express CD19 targeted CARs efficiently inhibited the proliferation of activated human T cells, as well as the capacity of CD19-targeted 19-28z+ effector T cells to lyse CD19+ Raji tumor cells. Intravenous infusion of CD19-targeted nTregs into SCID-Beige mice with systemic Raji tumors traffic to sites of tumor and recapitulate a clinically relevant hostile tumor microenvironment. Anti-tumor efficacy of subsequently infused 19-28z+ effector T cells was fully abrogated as assessed by long-term survival of treated mice. Optimal suppression by genetically targeted nTregs was dependent on nTreg to effector T cell ratios and in vivo nTreg activation. Prior infusion of cyclophosphamide in the setting of this nTreg-mediated hostile microenvironment was able to restore the anti-tumor activity of subsequently infused 19-28z+ effector T cells through the eradication of tumor targeted nTregs. These findings have significant implications on the design of future clinical trials utilizing CAR-based adoptive T cell therapies of cancer. PMID:21487038

  9. A77 1726, the active metabolite of leflunomide, attenuates lupus nephritis by promoting the development of regulatory T cells and inhibiting IL-17-producing double negative T cells.

    PubMed

    Qiao, Guilin; Yang, Lifen; Li, Zhenping; Williams, James W; Zhang, Jian

    2015-04-01

    Lupus nephritis (LN) is a challenging problem that affects 50% of patients with systemic lupus erythematosus (SLE) without effective therapy. Here, we report that A77 1726, the active metabolite of leflunomide, effectively inhibits development of LN and attenuates the generalized autoimmune features. A77 1726 suppresses the expansion of double negative (DN) T cells, and inhibits T and B cell activation. Intriguingly, A77 1726 treatment significantly increases CD4(+)Foxp3(+) regulatory T cells but suppresses potential "pathogenic" IL-17-producing DN T cells in lymph nodes. In vitro experiment shows that A77 1726 potentiates the conversion of naive CD4(+)CD25(-) T cells into CD4(+)CD25(+)Foxp3(+) inducible regulatory T cells (iTregs) by inhibiting Akt. Taken together, our data indicate that the therapeutic effects of A77 1726 in murine LN are mediated, at least in part, by augmenting iTregs which suppress pathogenic IL-17-producing DN T cells through an Akt-dependent mechanism. PMID:25638413

  10. MEK inhibition prevents tumour-shed transforming growth factor-β-induced T-regulatory cell augmentation in tumour milieu.

    PubMed

    Hossain, Dewan M S; Panda, Abir K; Chakrabarty, Sreeparna; Bhattacharjee, Pushpak; Kajal, Kirti; Mohanty, Suchismita; Sarkar, Irene; Sarkar, Diptendra K; Kar, Santosh K; Sa, Gaurisankar

    2015-04-01

    Tumour progression is associated with immune-suppressive conditions that facilitate the escape of tumour cells from the regimen of immune cells, subsequently paralysing the host defence mechanisms. Induction of CD4(+)  CD25(+)  FoxP3(+) T regulatory (Treg) cells has been implicated in the tumour immune escape mechanism, although the novel anti-cancer treatment strategies targeting Treg cells remain unknown. The focus of this study is to define the interaction between tumour and immune system, i.e. how immune tolerance starts and gradually leads to the induction of adaptive Treg cells in the tumour microenvironment. Our study identified hyperactivated mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) -signalling as a potential target for reversing Treg cell augmentation in breast cancer patients. In more mechanistic detail, pharmacological inhibitors of MEK/ERK signalling inhibited transforming growth factor-β (TGF-β) production in tumour cells that essentially blocked TGF-β-SMAD3/SMAD4-mediated induction of CD25/interleukin-2 receptor α on CD4(+) T-cell surface. As a result high-affinity binding of interleukin-2 on those cells was prohibited, causing lack of Janus kinase 1 (JAK1)/JAK3-mediated signal transducer and activator of transcription 3 (STAT3)/STAT5 activation required for FoxP3 expression. Finally, for a more radical approach towards a safe MEK inhibitor, we validate the potential of multi-kinase inhibitor curcumin, especially the nano-curcumin made out of pure curcumin with greater bioavailability; in repealing tumour-shed TGF-β-induced Treg cell augmentation. PMID:25284464

  11. Inhibition of ovarian cancer cell proliferation in vivo and incorporation of /sup 3/H-thymidine in vitro after follicle regulatory protein administration

    SciTech Connect

    Rodgers, K.E.; Montz, F.J.; Scott, L.; Condon, S.; Fujimori, K.; diZerega, G.S.

    1989-01-01

    Follicle regulatory protein immunoreactivity and biologic activity were measured in ascites from a patient with juvenile granulosa cell tumor. Microscopic examination of immunohistochemical staining of a juvenile granulosa cell tumor with anti-follicle regulatory protein antisera showed homogeneous cytosolic expression of follicle regulatory protein throughout the tumor. Tumor cells were injected subcutaneously into nude mice. Partially purified follicle regulatory protein (50 micrograms/day) was then injected daily for 10 days, or for 25 days once the tumor became palpable. Treatment with follicle regulatory protein significantly slowed the rate of tumor growth with both treatments. To test the tissue specificity of the effect, a metastatic, well-differentiated endometrial adenocarcinoma was also grown in nude mice. Follicle regulatory protein treatment did not alter the rate of tumor growth. An in vitro clonigenic assay confirmed these in vivo results. Partially purified follicle regulatory protein had a biphasic effect on the proliferation of juvenile granulosa tumor cell but did not affect the proliferation of endometrial adenocarcinoma cells. Clonigenic assays were performed on five ovarian adenocarcinomas passaged in vitro, and these tumor cells exhibited a biphasic response to follicle regulatory protein. Immunoneutralization studies showed that this biphasic response was due to impurities in the follicle regulatory protein preparations. The longer the exposure of the tumor cells to follicle regulatory protein, the greater the degree of inhibition of proliferation. In summary, administration of follicle regulatory protein slowed tumor growth through a direct effect on the tumor cell rather than an indirect effect on the hormonal or immune status of the host.

  12. Suppression of complement regulatory protein C1 inhibitor in vascular endothelial activation by inhibiting vascular cell adhesion molecule-1 action

    SciTech Connect

    Zhang, Haimou; Qin, Gangjian; Liang, Gang; Li, Jinan; Chiu, Isaac; Barrington, Robert A.; Liu, Dongxu . E-mail: dxliu001@yahoo.com

    2007-07-13

    Increased expression of adhesion molecules by activated endothelium is a critical feature of vascular inflammation associated with the several diseases such as endotoxin shock and sepsis/septic shock. Our data demonstrated complement regulatory protein C1 inhibitor (C1INH) prevents endothelial cell injury. We hypothesized that C1INH has the ability of an anti-endothelial activation associated with suppression of expression of adhesion molecule(s). C1INH blocked leukocyte adhesion to endothelial cell monolayer in both static assay and flow conditions. In inflammatory condition, C1INH reduced vascular cell adhesion molecule (VCAM-1) expression associated with its cytoplasmic mRNA destabilization and nuclear transcription level. Studies exploring the underlying mechanism of C1INH-mediated suppression in VCAM-1 expression were related to reduction of NF-{kappa}B activation and nuclear translocation in an I{kappa}B{alpha}-dependent manner. The inhibitory effects were associated with reduction of inhibitor I{kappa}B kinase activity and stabilization of the NF-{kappa}B inhibitor I{kappa}B. These findings indicate a novel role for C1INH in inhibition of vascular endothelial activation. These observations could provide the basis for new therapeutic application of C1INH to target inflammatory processes in different pathologic situations.

  13. T follicular regulatory cells.

    PubMed

    Sage, Peter T; Sharpe, Arlene H

    2016-05-01

    Pathogen exposure elicits production of high-affinity antibodies stimulated by T follicular helper (Tfh) cells in the germinal center reaction. Tfh cells provide both costimulation and stimulatory cytokines to B cells to facilitate affinity maturation, class switch recombination, and plasma cell differentiation within the germinal center. Under normal circumstances, the germinal center reaction results in antibodies that precisely target foreign pathogens while limiting autoimmunity and excessive inflammation. In order to have this degree of control, the immune system ensures Tfh-mediated B-cell help is regulated locally in the germinal center. The recently identified T follicular regulatory (Tfr) cell subset can migrate to the germinal center and inhibit Tfh-mediated B-cell activation and antibody production. Although many aspects of Tfr cell biology are still unclear, recent data have begun to delineate the specialized roles of Tfr cells in controlling the germinal center reaction. Here we discuss the current understanding of Tfr-cell differentiation and function and how this knowledge is providing new insights into the dynamic regulation of germinal centers, and suggesting more efficacious vaccine strategies and ways to treat antibody-mediated diseases. PMID:27088919

  14. Multipotent Mesenchymal Stromal Cells Synergize With Costimulation Blockade in the Inhibition of Immune Responses and the Induction of Foxp3+ Regulatory T Cells

    PubMed Central

    Tibell, Annika; Ljung, Karin; Saito, Yu; Gronlund, Anna; Osterholm, Cecilia; Holgersson, Jan; Lundgren, Torbjörn; Ericzon, Bo-Göran; Corbascio, Matthias; Kumagai-Braesch, Makiko

    2014-01-01

    Multipotent mesenchymal stromal cell (MSC) therapy and costimulation blockade are two immunomodulatory strategies being developed concomitantly for the treatment of immunological diseases. Both of these strategies have the capacity to inhibit immune responses and induce regulatory T cells; however, their ability to synergize remains largely unexplored. In order to study this, MSCs from C57BL/6 (H2b) mice were infused together with fully major histocompatibility complex-mismatched Balb/c (H2d) allogeneic islets into the portal vein of diabetic C57BL/6 (H2b) mice, which were subsequently treated with costimulation blockade for the first 10 days after transplantation. Mice receiving both recipient-type MSCs, CTLA4Ig, and anti-CD40L demonstrated indefinite graft acceptance, just as did most of the recipients receiving MSCs and CTLA4Ig. Recipients of MSCs only rejected their grafts, and fewer than one half of the recipients treated with costimulation blockade alone achieved permanent engraftment. The livers of the recipients treated with MSCs plus costimulation blockade contained large numbers of islets surrounded by Foxp3+ regulatory T cells. These recipients showed reduced antidonor IgG levels and a glucose tolerance similar to that of naïve nondiabetic mice. Intrahepatic lymphocytes and splenocytes from these recipients displayed reduced proliferation and interferon-γ production when re-exposed to donor antigen. MSCs in the presence of costimulation blockade prevented dendritic cell maturation, inhibited T cell proliferation, increased Foxp3+ regulatory T cell numbers, and increased indoleamine 2,3-dioxygenase activity. These results indicate that MSC infusion and costimulation blockade have complementary immune-modulating effects that can be used for a broad number of applications in transplantation, autoimmunity, and regenerative medicine. PMID:25313200

  15. Sialic acid-modified antigens impose tolerance via inhibition of T-cell proliferation and de novo induction of regulatory T cells.

    PubMed

    Perdicchio, Maurizio; Ilarregui, Juan M; Verstege, Marleen I; Cornelissen, Lenneke A M; Schetters, Sjoerd T T; Engels, Steef; Ambrosini, Martino; Kalay, Hakan; Veninga, Henrike; den Haan, Joke M M; van Berkel, Lisette A; Samsom, Janneke N; Crocker, Paul R; Sparwasser, Tim; Berod, Luciana; Garcia-Vallejo, Juan J; van Kooyk, Yvette; Unger, Wendy W J

    2016-03-22

    Sialic acids are negatively charged nine-carbon carboxylated monosaccharides that often cap glycans on glycosylated proteins and lipids. Because of their strategic location at the cell surface, sialic acids contribute to interactions that are critical for immune homeostasis via interactions with sialic acid-binding Ig-type lectins (siglecs). In particular, these interactions may be of importance in cases where sialic acids may be overexpressed, such as on certain pathogens and tumors. We now demonstrate that modification of antigens with sialic acids (Sia-antigens) regulates the generation of antigen-specific regulatory T (Treg) cells via dendritic cells (DCs). Additionally, DCs that take up Sia-antigen prevent formation of effector CD4(+) and CD8(+)T cells. Importantly, the regulatory properties endowed on DCs upon Sia-antigen uptake are antigen-specific: only T cells responsive to the sialylated antigen become tolerized. In vivo, injection of Sia-antigen-loaded DCs increased de novo Treg-cell numbers and dampened effector T-cell expansion and IFN-γ production. The dual tolerogenic features that Sia-antigen imposed on DCs are Siglec-E-mediated and maintained under inflammatory conditions. Moreover, loading DCs with Sia-antigens not only inhibited the function of in vitro-established Th1 and Th17 effector T cells but also significantly dampened ex vivo myelin-reactive T cells, present in the circulation of mice with experimental autoimmune encephalomyelitis. These data indicate that sialic acid-modified antigens instruct DCs in an antigen-specific tolerogenic programming, enhancing Treg cells and reducing the generation and propagation of inflammatory T cells. Our data suggest that sialylation of antigens provides an attractive way to induce antigen-specific immune tolerance. PMID:26941238

  16. Sialic acid-modified antigens impose tolerance via inhibition of T-cell proliferation and de novo induction of regulatory T cells

    PubMed Central

    Perdicchio, Maurizio; Ilarregui, Juan M.; Verstege, Marleen I.; Cornelissen, Lenneke A. M.; Schetters, Sjoerd T. T.; Engels, Steef; Ambrosini, Martino; Kalay, Hakan; Veninga, Henrike; den Haan, Joke M. M.; van Berkel, Lisette A.; Samsom, Janneke N.; Crocker, Paul R.; Sparwasser, Tim; Berod, Luciana; Garcia-Vallejo, Juan J.; van Kooyk, Yvette; Unger, Wendy W. J.

    2016-01-01

    Sialic acids are negatively charged nine-carbon carboxylated monosaccharides that often cap glycans on glycosylated proteins and lipids. Because of their strategic location at the cell surface, sialic acids contribute to interactions that are critical for immune homeostasis via interactions with sialic acid-binding Ig-type lectins (siglecs). In particular, these interactions may be of importance in cases where sialic acids may be overexpressed, such as on certain pathogens and tumors. We now demonstrate that modification of antigens with sialic acids (Sia-antigens) regulates the generation of antigen-specific regulatory T (Treg) cells via dendritic cells (DCs). Additionally, DCs that take up Sia-antigen prevent formation of effector CD4+ and CD8+ T cells. Importantly, the regulatory properties endowed on DCs upon Sia-antigen uptake are antigen-specific: only T cells responsive to the sialylated antigen become tolerized. In vivo, injection of Sia-antigen–loaded DCs increased de novo Treg-cell numbers and dampened effector T-cell expansion and IFN-γ production. The dual tolerogenic features that Sia-antigen imposed on DCs are Siglec-E–mediated and maintained under inflammatory conditions. Moreover, loading DCs with Sia-antigens not only inhibited the function of in vitro–established Th1 and Th17 effector T cells but also significantly dampened ex vivo myelin-reactive T cells, present in the circulation of mice with experimental autoimmune encephalomyelitis. These data indicate that sialic acid-modified antigens instruct DCs in an antigen-specific tolerogenic programming, enhancing Treg cells and reducing the generation and propagation of inflammatory T cells. Our data suggest that sialylation of antigens provides an attractive way to induce antigen-specific immune tolerance. PMID:26941238

  17. Inhibition of miR301 enhances Akt-mediated cell proliferation by accumulation of PTEN in nucleus and its effects on cell-cycle regulatory proteins

    PubMed Central

    Jain, Mayur V.; Shareef, Ahmad; Likus, Wirginia; Cieślar-Pobuda, Artur; Ghavami, Saeid; Łos, Marek J.

    2016-01-01

    Micro-RNAs (miRs) represent an innovative class of genes that act as regulators of gene expression. Recently, the aberrant expression of several miRs has been associated with different types of cancers. In this study, we show that miR301 inhibition influences PI3K-Akt pathway activity. Akt overexpression in MCF7 and MDAMB468 cells caused downregulation of miR301 expression. This effect was confirmed by co-transfection of miR301-modulators in the presence of Akt. Cells overexpressing miR301-inhibitor and Akt, exhibited increased migration and proliferation. Experimental results also confirmed PI3K, PTEN and FoxF2 as regulatory targets for miR301. Furthermore, Akt expression in conjunction with miR301-inhibitor increased nuclear accumulation of PTEN, thus preventing it from downregulating the PI3K-signalling. In summary, our data emphasize the importance of miR301 inhibition on PI3K-Akt pathway-mediated cellular functions. Hence, it opens new avenues for the development of new anti-cancer agents preferentially targeting PI3K-Akt pathway. PMID:26967567

  18. Antitumor activity of total flavonoids from Tetrastigma hemsleyanum Diels et Gilg is associated with the inhibition of regulatory T cells in mice

    PubMed Central

    Feng, Zhengquan; Hao, Wanrong; Lin, Xiaoyang; Fan, Daping; Zhou, Juhua

    2014-01-01

    Objective To determine the antitumor activity of Radix tetrastigmae flavonoids and their inhibitory effect on regulatory T cells (Tregs) in mice. Materials and methods Total flavonoids were isolated from Radix tetrastigmae, the root of Tetrastigma hemsleyanum Diels et Gilg, and administered to C57BL/6 mice by oral gavage after inoculation with Lewis lung carcinoma (LLC) cells. The effects of total flavonoids on tumor growth in vivo were examined. Flow cytometry was used to study the effects on Tregs, and enzyme-linked immunosorbent assay was used to analyze the changes in the serum levels of transforming growth factor β, prostaglandin E2, and cyclooxygenase 2 after tumor inoculation and flavonoid administration. Results Total flavonoids from T. hemsleyanum Diels et Gilg significantly inhibited tumor growth in C57BL/6 mice inoculated with LLCs. These flavonoids dramatically suppressed regulatory T-cell development in tumor-bearing mice. Further studies revealed that total flavonoids significantly decreased the serum levels of transforming growth factor β, prostaglandin E2, and cyclooxygenase 2 in tumor-bearing mice, which may be responsible for the inhibition of Tregs. Conclusion The antitumor activity of total flavonoids from T. hemsleyanum Diels et Gilg is associated with the inhibition of Tregs in a mouse tumor model. Total flavonoids from T. hemsleyanum Diels et Gilg may be used as antitumor agents in cancer prevention and treatment. PMID:24959081

  19. A novel function of interferon regulatory factor-1: inhibition of Th2 cells by down-regulating the Il4 gene during Listeria infection.

    PubMed

    Maruyama, Saho; Kanoh, Makoto; Matsumoto, Akira; Kuwahara, Makoto; Yamashita, Masakatsu; Asano, Yoshihiro

    2015-03-01

    Infection with certain pathogens induces a shift of the Th subset balance to a Th1 dominant state. This, in turn, results in the suppression of Th2 responses. We focused on the involvement of interferon regulatory factor-1 (IRF-1) in the suppression of Th2 cells during Listeria infection. We found that the inhibition of IL-4 production by Th2 cells is mediated by a soluble factor (LmSN) produced by Listeria-infected antigen-presenting cells. The inhibition is not observed with T cells from Irf1 gene-targeted mice. IRF-1 suppresses transcription of the Il4 gene in Th2 cells. Under the influence of the LmSN, IRF-1 binds to the 3' untranslated region (UTR) region of the Il4 gene and down-regulates Il4 gene transcription. Finally, we identified IL-1α and IL-1β as the mediator of the LmSN activity. Signaling through IL-1R induces the stabilization and/or nuclear translocation of IRF-1. We propose that IRF-1 functions to induce the T-cell subset shift via a novel mechanism. Under the influence of IL-1, IRF-1 translocates into the nucleus and acts on the 3'UTR region of the Il4 gene, thus inhibiting its transcription in Th2 cells. As a result, the immune system shifts predominantly to a Th1 response during Listeria infection, resulting in effective protection of the host. PMID:25280793

  20. Immunoglobulin E signal inhibition during allergen ingestion leads to reversal of established food allergy and induction of regulatory T cells.

    PubMed

    Burton, Oliver T; Noval Rivas, Magali; Zhou, Joseph S; Logsdon, Stephanie L; Darling, Alanna R; Koleoglou, Kyle J; Roers, Axel; Houshyar, Hani; Crackower, Michael A; Chatila, Talal A; Oettgen, Hans C

    2014-07-17

    Immunoglobulin E (IgE) antibodies are known for triggering immediate hypersensitivity reactions such as food anaphylaxis. In this study, we tested whether they might additionally function to amplify nascent antibody and T helper 2 (Th2) cell-mediated responses to ingested proteins and whether blocking IgE would modify sensitization. By using mice harboring a disinhibited form of the IL-4 receptor, we developed an adjuvant-free model of peanut allergy. Mast cells and IgE were required for induction of antibody and Th2-cell-mediated responses to peanut ingestion and they impaired regulatory T (Treg) cell induction. Mast-cell-targeted genetic deletion of the FcεRI signaling kinase Syk or Syk blockade also prevented peanut sensitization. In mice with established allergy, Syk blockade facilitated desensitization and induction of Treg cells, which suppressed allergy when transferred to naive recipients. Our study suggests a key role for IgE in driving Th2 cell and IgE responses while suppressing Treg cells in food allergy. PMID:25017467

  1. Inhibition of viral replication reduces regulatory T cells and enhances the antiviral immune response in chronic hepatitis B

    SciTech Connect

    Stoop, Jeroen N. . E-mail: j.n.stoop@erasmusmc.nl; Molen, Renate G. van der . E-mail: r.vandermolen@erasmusmc.nl; Kuipers, Ernst J. . E-mail: e.j.kuipers@erasmusmc.nl; Kusters, Johannes G. . E-mail: j.g.kusters@erasmusmc.nl; Janssen, Harry L.A. . E-mail: h.janssen@erasmusmc.nl

    2007-04-25

    Regulatory T cells (Treg) play a key role in the impaired immune response that is typical for a chronic Hepatitis B virus (HBV) infection. To gain more insight in the mechanism that is responsible for this impaired immune response, the effect of viral load reduction resulting from treatment with the nucleotide analogue adefovir dipivoxil on the percentages of Treg and HBV-specific T-cell responses was analyzed. Peripheral blood mononuclear cells (PBMC) of 12 patients were collected at baseline and during treatment. In parallel to the decline in viral load, we found a decline in circulating Treg, combined with an increase in HBV core antigen-specific IFN-{gamma} production and proliferation. The production of IL10 did not decrease during therapy. In conclusion, adefovir induced viral load reduction results in a decline of circulating Treg together with a partial recovery of the immune response.

  2. Dimethyl sulfoxide inhibits spontaneous diabetes and autoimmune recurrence in non-obese diabetic mice by inducing differentiation of regulatory T cells

    SciTech Connect

    Lin, Gu-Jiun; Sytwu, Huey-Kang; Yu, Jyh-Cherng; Chen, Yuan-Wu; Kuo, Yu-Liang; Yu, Chiao-Chi; Chang, Hao-Ming; Chan, De-Chuan; Huang, Shing-Hwa

    2015-01-15

    Type 1 diabetes mellitus (T1D) is caused by the destruction of insulin-producing β cells in pancreatic islets by autoimmune T cells. Islet transplantation has been established as an effective therapeutic strategy for T1D. However, the survival of islet grafts can be disrupted by recurrent autoimmunity. Dimethyl sulfoxide (DMSO) is a solvent for organic and inorganic substances and an organ-conserving agent used in solid organ transplantations. DMSO also exerts anti-inflammatory, reactive oxygen species scavenger and immunomodulatory effects and therefore exhibits therapeutic potential for the treatment of several human inflammatory diseases. In this study, we investigated the therapeutic potential of DMSO in the inhibition of autoimmunity. We treated an animal model of islet transplantation (NOD mice) with DMSO. The survival of the syngeneic islet grafts was significantly prolonged. The population numbers of CD8, DC and Th1 cells were decreased, and regulatory T (Treg) cell numbers were increased in recipients. The expression levels of IFN-γ and proliferation of T cells were also reduced following DMSO treatment. Furthermore, the differentiation of Treg cells from naive CD4 T cells was significantly increased in the in vitro study. Our results demonstrate for the first time that in vivo DMSO treatment suppresses spontaneous diabetes and autoimmune recurrence in NOD mice by inhibiting the Th1 immune response and inducing the differentiation of Treg cells. - Highlights: • We report a therapeutic potential of DMSO in autoimmune diabetes. • DMSO exhibits an immune modulatory effect. • DMSO treatment increases regulatory T cell differentiation. • The increase in STAT5 signaling pathway explains the effect of DMSO in Tregs.

  3. Tumor-specific Th2 responses inhibit growth of CT26 colon-cancer cells in mice via converting intratumor regulatory T cells to Th9 cells.

    PubMed

    Liu, Jiang-Qi; Li, Xing-Yong; Yu, Hai-Qiong; Yang, Gui; Liu, Zhi-Qiang; Geng, Xiao-Rui; Wang, Shuai; Mo, Li-Hua; Zeng, Lu; Zhao, Miao; Fu, Yun-Ting; Sun, Hong-Zhi; Liu, Zhi-Gang; Yang, Ping-Chang

    2015-01-01

    The abnormality of immune regulation plays a critical role in the pathogenesis of cancer; the underlying mechanism has not been fully understood yet. This study aims to investigate the role of cancer specific T helper (Th)2 response in the inhibition of colon cancer (Cca) cell growth. The results showed that with Cca cell (CT26 cell) extracts as an antigen, the Cca-extract specific Th2 response was induced in the Cca-bearing mice. The Cca mass size was significantly reduced, or radically disappeared (5 out of 10; or 50%); the survival rate was markedly improved in mice immunized with Cca-extract, but not in those immunized with another tumor cell (U87 cell) extracts or to bovine serum albumin. The immunization with Cca-extract also induced Cca cell apoptosis and converted the intra-Cca Tregs to T helper (Th) 9 cells. In conclusion, Cca-specific Th2 responses inhibit Cca growth in a mouse model via inducing Cca cell apoptosis and converting intra-Cca Tregs to Th9 cells. PMID:26035423

  4. T regulatory cells in allergy.

    PubMed

    Braga, M; Quecchia, C; Cavallucci, E; Di Giampaolo, L; Schiavone, C; Petrarca, C; Di Gioacchino, M

    2011-01-01

    The progressive understanding of the nature and mechanisms of T regulatory (Treg) cells in the last decade has changed the concept of immune tolerance, that is no longer considered as a mere lack of immune reactivity but as a finely regulated process that requires specific activity of cells, adhesion and secreted molecules. Tregs play a key role in maintenance of self-tolerance and induction of tolerance against ubiquitous innocuous non-self antigens, so preventing the onset of autoimmune diseases and allergies. This review will focus on the Treg response in allergy that is characterized by a down-regulation of allergen specific T cell proliferation and inhibition of both Th1 and Th2 cytokines production. Hence, Treg cells suppress allergen-specific Th1 and Th2 cell responses playing an important role in the physiological immune response to allergens. Further, Treg cells are able to suppress IgE production by B lymphocytes and directly or indirectly inhibit the activity of allergic inflammation effector cells, namely eosinophils, basophils and mastcells. Finally, increasing evidence suggests that Treg cells are also implicated in chronicity development of inflammatory diseases. This appears to happen through a fine interaction they entertain with resident tissue cells and has been particularly highlighted in the study of airways remodeling in asthma. The understanding of the mechanisms underlying allergen tolerance has brought new interest in the development of new allergy treatment, able to target Treg cells, both in allergy prevention and in the therapy of established allergy. PMID:21329567

  5. Phospholipase A2 inhibits cisplatin-induced acute kidney injury by modulating regulatory T cells by the CD206 mannose receptor.

    PubMed

    Kim, Hyunseong; Lee, Hyojung; Lee, Gihyun; Jang, Hyunil; Kim, Sung-Su; Yoon, Heera; Kang, Geun-Hyung; Hwang, Deok-Sang; Kim, Sun Kwang; Chung, Hwan-Suck; Bae, Hyunsu

    2015-09-01

    Previously, we found that Foxp3-expressing CD4(+) regulatory T (Treg) cells attenuate cisplatin-induced acute kidney injury in mice and that bee venom and its constituent phospholipase A2 (PLA2) are capable of modulating Treg cells. Here we tested whether PLA2 could inhibit cisplatin-induced acute kidney injury. As a result of treatment with PLA2, the population of Treg cells was significantly increased, both in vivo and in vitro. PLA2-injected mice showed reduced levels of serum creatinine, blood urea nitrogen, renal tissue damage, and pro-inflammatory cytokine production upon cisplatin administration. These renoprotective effects were abolished by depletion of Treg cells. Furthermore, PLA2 bound to CD206 mannose receptors on dendritic cells, essential for the PLA2-mediated protective effects on renal dysfunction. Interestingly, PLA2 treatment increased the secretion of IL-10 in the kidney from normal mice. Foxp3(+)IL-10(+) cells and CD11c(+)IL-10(+) cells were increased by PLA2 treatment. The anticancer effects of repeated administrations of a low dose of cisplatin were not affected by PLA2 treatment in a tumor-bearing model. Thus, PLA2 may prevent inflammatory responses in cisplatin-induced acute kidney injury by modulating Treg cells and IL-10 through the CD206 mannose receptor. PMID:25993317

  6. Regulatory T cells: a review.

    PubMed

    Dasgupta, Alakananda; Saxena, Renu

    2012-01-01

    Regulatory T cells (Tregs) play a pivotal role in the homeostasis of the immune system and in the modulation of the immune response. Tregs have emerged as key players in the development and maintenance of peripheral immune tolerance. Broadly speaking, CD4+ T cells possessing the ability to suppress immune responses can be divided into two types: naturally occurring (nTreg) and inducible (iTreg) or adaptive regulatory cells. Naturally occurring thymus-derived CD4+CD25+ Tregs are a subset of T cells which have immunosuppressive properties and are 5%-10% of the total peripheral CD4+ T cells. In normal conditions, Tregs regulate ongoing immune responses and prevent autoimmunity. Imbalanced function or number of these cells, either enhanced or decreased, might lead to tumour development and autoimmunity, respectively. These cells thus play a major role in autoimmune diseases, transplantation tolerance, infectious diseases, allergic disease and tumour immunity. These natural properties make Tregs attractive tools for novel immunotherapeutic approaches. The in vivo manipulation or depletion of Tregs may help devise effective immunotherapy for patients with cancer, autoimmunity, graftversus-host disease, infectious diseases and allergic diseases. It is crucial to understand the biology of Tregs before attempting therapies, including (i) the injection of expanded Tregs to cure autoimmune disease or prevent graft-versus-host disease or (ii) the depletion or inhibition of Tregs in cancer therapy. Recent findings in murine models and studies in humans have opened new avenues to study the biology of Tregs and their therapeutic potential. This overview provides a framework for integrating these concepts of basic and translational research. PMID:23998865

  7. [Regulatory B cells activated by CpG-ODN combined with anti-CD40 monoclonal antibody inhibit CD4(+)T cell proliferation].

    PubMed

    Wang, Keng; Tao, Lei; Su, Jianbing; Zhang, Yueyang; Zou, Binhua; Wang, Yiyuan; Li, Xiaojuan

    2016-09-01

    Objective To observe the immunosuppressive function of regulatory B cells (Bregs) in vitro after activated by CpG oligodeoxynucleotide (CpG-ODN) and anti-CD40 mAb. Methods Mice splenic CD5(+)CD1d(high)B cells and CD5(-)CD1d(low)B cells were sorted by flow cytometry. These B cells were first stimulated with CpG-ODN combined with anti-CD40 mAb for 24 hours, and then co-cultured with purified CD4(+)T cells. The interleukin 10 (IL-10) expression in the activated Bregs and other B cell subset, as well as the proliferation and interferon γ (IFN-γ) expression in the CD4(+) T cells activated by anti-CD3 mAb plus anti-CD28 mAb were determined by flow cytometry. Results CD5(+)CD1d(high) B cells activated by CpG-ODN plus anti-CD40 mAb blocked the up-regulated CD4(+)T proliferation and significantly reduced the IFN-γ level. At the same time, activated CD5(-)CD1d(low)B cells showed no inhibitory effect on CD4(+)T cells. Further study revealed that IL-10 expression in the CD5(+)CD1d(high) B cells were much higher than that in the CD5(-)CD1d(low)B cells after stimulated with CpG-ODN combined with anti-CD40 mAb for 24 hours. Conclusion CD5(+)CD1d(high) B cells activated by CpG-ODN combined with anti-CD40 mAb have immune inhibitory effects on CD4(+)T cell activation in vitro , which possibly due to IL-10 secretion. PMID:27609568

  8. In human alloreactive CD4+ T-cells, dichloroacetate inhibits aerobic glycolysis, induces apoptosis and favors differentiation towards the regulatory T-cell subset instead of effector T-cell subsets.

    PubMed

    Eleftheriadis, Theodoros; Sounidaki, Maria; Pissas, Georgios; Antoniadi, Georgia; Liakopoulos, Vassilios; Stefanidis, Ioannis

    2016-04-01

    Although kidney transplantation is the best therapy for end-stage renal disease, rejection remains a concern, and currently available immunosuppressive agents contribute to morbidity and mortality. Thus, novel immunosuppressive drugs are required. Dichloroacetate (DCA) is already used in the treatment of congenital lactic acidosis and characterized by limited toxicity. As DCA inhibits aerobic glycolysis, which is a prerequisite for CD4+ T-cell proliferation and differentiation into effector T-cells, its possible immunosuppressive role in mixed lymphocyte reaction (MLR), a model of alloreactivity, was investigated. Glucose and lactate concentrations were measured in the supernatants, and cell proliferation was assessed immunoenzymatically. CD4+ T‑cells were then isolated from the MLRs and the expression of cleaved caspase‑3, various enzymes involved in glycolysis, and the signature transcription factors of CD4+ T‑cell subsets were evaluated by western blotting. In MLRs, DCA decreased glucose consumption and aerobic glycolysis, while it exerted a negligible effect on cell proliferation. In CD4+ T‑cells, DCA induced apoptosis, and decreased the expression of glucose trasporter‑1, hexokinase II, lactate dehydrogenase‑A and phosphorylated pyruvate dehydrogenase, while it increased total pyruvate dehydrogenase. In addition, DCA increased the expression of transcription factor forkhead box P3, whereas it decreased the expression of T‑box transcription factor TBX21, trans‑acting T-cell-specific transcription factor GATA‑3 and retinoic acid receptor related orphan receptor‑γt. In conclusion, in alloreactive CD4+ T‑cells, DCA inhibits aerobic glycolysis, induces apoptosis and favors differentiation towards the regulatory T‑cell subset. These characteristics render it a promising immunosuppressive agent in the field of transplantation. PMID:26935268

  9. In vitro exposure to the herbicide atrazine inhibits T cell activation, proliferation, and cytokine production and significantly increases the frequency of Foxp3+ regulatory T cells.

    PubMed

    Thueson, Lindsay E; Emmons, Tiffany R; Browning, Dianna L; Kreitinger, Joanna M; Shepherd, David M; Wetzel, Scott A

    2015-02-01

    The herbicide atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-s-triazine) is the most common water contaminant in the United States. Atrazine is a phosphodiesterase inhibitor and is classified as an estrogen disrupting compound because it elevates estrogen levels via induction of the enzyme aromatase. Previous studies have shown that atrazine exposure alters the function of innate immune cells such as NK cells, DC, mast cells, and macrophages. In this study we have examined the impact of in vitro atrazine exposure on the activation, proliferation, and effector cytokine production by primary murine CD4(+) T lymphocytes. We found that atrazine exposure significantly inhibited CD4(+) T cell proliferation and accumulation as well as the expression of the activation markers CD25 and CD69 in a dose-dependent manner. Interestingly, the effects were more pronounced in cells from male animals. These effects were partially mimicked by pharmacological reagents that elevate intracellular cAMP levels and addition of exogenous rmIL-2 further inhibited proliferation and CD25 expression. Consistent with these findings, atrazine exposure during T cell activation resulted in a 2- to 5-fold increase in the frequency of Foxp3(+) CD4(+) T cells. PMID:25433234

  10. CpG Oligodeoxynucleotide Inhibits Cockroach-Induced Asthma via Induction of IFN-γ+ Th1 Cells or Foxp3+ Regulatory T Cells in the Lung

    PubMed Central

    Kim, Do-Hyun; Sohn, Jung-Ho; Park, Hong-Jai; Lee, Jae-Hyun

    2016-01-01

    Purpose CpG oligodeoxynucleotide (CpG-ODN), a TLR9 agonist, activates innate immunity and induces Th1 response. Although the immune modulatory effect of CpG-ODN has been extensively studied, its function in cockroach extract-induced allergic asthma has not been studied. Here, we investigated the inhibitory function of CpG-ODN in cockroach extract-induced asthma in mice with different treatment schemes. Methods Scheme 1: BALB/C mice were intra-nasally co-administered by cockroach extract and CpG-ODN twice a week for 3 weeks; Scheme 2: The mice were intra-nasally pre-treated with CpG-ODN at day 0 and cockroach allergen challenge was performed from day 3 as in scheme 1. Scheme 3: Cockroach allergen challenge was performed as in scheme 1 and CpG-ODN was post-treated at day 21. Then, BAL cell count, flow cytometric analysis of alveolar macrophages, regulatory T cells, and lung tissue histology, Th1 and Th2 cytokines, serum IgE, cockroach specific IgE, IgG1/IgG2a ratio, and airway hyper-responsiveness were evaluated. Results Mice with repeated intra-nasal exposure to CpG-ODN showed a dramatic decrease in eosinophilic inflammation, goblet cell hyperplasia, and airway hyper-responsiveness with reduction of IL-13, IL-5, and serum IgE, cockroach specific IgE and IgG1/IgG2a ratio. This inhibitory function might be related to the up-regulation of IL-10 and CD4+Foxp3+ regulatory T cells in the lung. Interestingly, one-time challenge of CpG-ODN either prior or posterior to cockroach extract exposure could modulate airway inflammation and hyper-responsiveness via increase of Th1 response. Conclusions Collectively, our data suggest that CpG-ODN treatment modulates Th2 inflammation in the lung by induction of regulatory T cells or Th1 response in a cockroach-induced asthma model. PMID:26922937

  11. Early exposure of interferon-γ inhibits signal transducer and activator of transcription-6 signalling and nuclear factor κB activation in a short-term monocyte-derived dendritic cell culture promoting ‘FAST’ regulatory dendritic cells

    PubMed Central

    Rojas-Canales, D; Krishnan, R; Jessup, C F; Coates, P T

    2012-01-01

    Interferon (IFN)-γ is a cytokine with immunomodulatory properties, which has been shown previously to enhance the generation of tolerogenic dendritic cells (DC) when administered early ex vivo in 7-day monocyte-derived DC culture. To generate tolerogenic DC rapidly within 48 h, human monocytes were cultured for 24 h with interleukin (IL)-4 and granulocyte–macrophage colony-stimulating factor (GM-CSF) in the presence (IFN-γ-DC) or absence of IFN-γ (500 U/ml) (UT-DC). DC were matured for 24 h with TNF-α and prostaglandin E2 (PGE2). DC phenotype, signal transducer and activator of transcription-6 (STAT-6) phosphorylation and promotion of CD4+CD25+CD127neg/lowforkhead box P3 (FoxP3)hi T cells were analysed by flow cytometry. DC nuclear factor (NF)-κB transcription factor reticuloendotheliosis viral oncogene homologue B (RELB) and IL-12p70 protein expression were also determined. Phenotypically, IFN-γ-DC displayed reduced DC maturation marker CD83 by 62% and co-stimulation molecules CD80 (26%) and CD86 (8%). IFN-γ treatment of monocytes inhibited intracellular STAT6, RELB nuclear translocation and IL-12p70 production. IFN-γ-DC increased the proportion of CD4+CD25+CD127neg/lowfoxp3hi T cells compared to UT-DC from 12 to 23%. IFN-γ-DC primed T cells inhibited antigen-specific, autologous naive T cell proliferation by 70% at a 1:1 naive T cells to IFN-γ-DC primed T cell ratio in suppression assays. In addition, we examined the reported paradoxical proinflammatory effects of IFN-γ and confirmed in this system that late IFN-γ exposure does not inhibit DC maturation marker expression. Early IFN-γ exposure is critical in promoting the generation of regulatory DC. Early IFN-γ modulated DC generated in 48 h are maturation arrested and promote the generation of antigen-specific regulatory T cells, which may be clinically applicable as a novel cellular therapy for allograft rejection. PMID:22288588

  12. Inhibition of Regulatory Volume Decrease Enhances the Cytocidal Effect of Hypotonic Shock in Hepatocellular Carcinoma.

    PubMed

    Kudou, Michihiro; Shiozaki, Atsushi; Kosuga, Toshiyuki; Ichikawa, Daisuke; Konishi, Hirotaka; Morimura, Ryo; Komatsu, Shuhei; Ikoma, Hisashi; Fujiwara, Hitoshi; Okamoto, Kazuma; Hosogi, Shigekuni; Nakahari, Takashi; Marunaka, Yoshinori; Otsuji, Eigo

    2016-01-01

    Background : Hypotonic shock induces cytocidal effects through cell rupture, and cancer therapy based on this mechanism has been clinically administered to hepatocellular carcinoma patients. We herein investigated the effectiveness of hypotonic shock combined with the inhibition of regulatory volume decrease as cancer therapy for hepatocellular carcinoma. Methods : Morphological changes in human hepatocellular carcinoma cell lines were observed under a differential interference contrast microscope connected to a high-speed digital video camera. Cell volume changes under hypotonic shock with or without chloride, potassium, or water channel blockers were observed using a high-resolution flow cytometer. In order to investigate cytocidal effects, the number of surviving cells was compared after exposure to hypotonic solution with and without each channel blocker (re-incubation experiment). Results : Video recordings showed that cells exposed to distilled water rapidly swelled and then ruptured. Cell volume measurements revealed regulatory volume decrease under mild hypotonic shock, whereas severe hypotonic shock increased the number of broken fragments as a result of cell rupture. Moreover, regulatory volume decrease was inhibited in cells treated with each channel blocker. Re-incubation experiments showed the cytocidal effects of hypotonic shock in cells exposed to hypotonic solution, and additional treatments with each channel blocker enhanced these effects. Conclusion : The inhibition of regulatory volume decrease with chloride, potassium, or water channel blockers may enhance the cytocidal effects of hypotonic shock in hepatocellular carcinoma. Hypotonic shock combined with the inhibition of regulatory volume decrease was a more effective therapy than hypotonic shock alone. PMID:27471568

  13. Inhibition of Regulatory Volume Decrease Enhances the Cytocidal Effect of Hypotonic Shock in Hepatocellular Carcinoma

    PubMed Central

    Kudou, Michihiro; Shiozaki, Atsushi; Kosuga, Toshiyuki; Ichikawa, Daisuke; Konishi, Hirotaka; Morimura, Ryo; Komatsu, Shuhei; Ikoma, Hisashi; Fujiwara, Hitoshi; Okamoto, Kazuma; Hosogi, Shigekuni; Nakahari, Takashi; Marunaka, Yoshinori; Otsuji, Eigo

    2016-01-01

    Background: Hypotonic shock induces cytocidal effects through cell rupture, and cancer therapy based on this mechanism has been clinically administered to hepatocellular carcinoma patients. We herein investigated the effectiveness of hypotonic shock combined with the inhibition of regulatory volume decrease as cancer therapy for hepatocellular carcinoma. Methods: Morphological changes in human hepatocellular carcinoma cell lines were observed under a differential interference contrast microscope connected to a high-speed digital video camera. Cell volume changes under hypotonic shock with or without chloride, potassium, or water channel blockers were observed using a high-resolution flow cytometer. In order to investigate cytocidal effects, the number of surviving cells was compared after exposure to hypotonic solution with and without each channel blocker (re-incubation experiment). Results: Video recordings showed that cells exposed to distilled water rapidly swelled and then ruptured. Cell volume measurements revealed regulatory volume decrease under mild hypotonic shock, whereas severe hypotonic shock increased the number of broken fragments as a result of cell rupture. Moreover, regulatory volume decrease was inhibited in cells treated with each channel blocker. Re-incubation experiments showed the cytocidal effects of hypotonic shock in cells exposed to hypotonic solution, and additional treatments with each channel blocker enhanced these effects. Conclusion: The inhibition of regulatory volume decrease with chloride, potassium, or water channel blockers may enhance the cytocidal effects of hypotonic shock in hepatocellular carcinoma. Hypotonic shock combined with the inhibition of regulatory volume decrease was a more effective therapy than hypotonic shock alone. PMID:27471568

  14. Regulatory T Cells Contribute to the Inhibition of Radiation-Induced Acute Lung Inflammation via Bee Venom Phospholipase A2 in Mice

    PubMed Central

    Shin, Dasom; Lee, Gihyun; Sohn, Sung-Hwa; Park, Soojin; Jung, Kyung-Hwa; Lee, Ji Min; Yang, Jieun; Cho, Jaeho; Bae, Hyunsu

    2016-01-01

    Bee venom has long been used to treat various inflammatory diseases, such as rheumatoid arthritis and multiple sclerosis. Previously, we reported that bee venom phospholipase A2 (bvPLA2) has an anti-inflammatory effect through the induction of regulatory T cells. Radiotherapy is a common anti-cancer method, but often causes adverse effects, such as inflammation. This study was conducted to evaluate the protective effects of bvPLA2 in radiation-induced acute lung inflammation. Mice were focally irradiated with 75 Gy of X-rays in the lung and administered bvPLA2 six times after radiation. To evaluate the level of inflammation, the number of immune cells, mRNA level of inflammatory cytokine, and histological changes in the lung were measured. BvPLA2 treatment reduced the accumulation of immune cells, such as macrophages, neutrophils, lymphocytes, and eosinophils. In addition, bvPLA2 treatment decreased inflammasome-, chemokine-, cytokine- and fibrosis-related genes’ mRNA expression. The histological results also demonstrated the attenuating effect of bvPLA2 on radiation-induced lung inflammation. Furthermore, regulatory T cell depletion abolished the therapeutic effects of bvPLA2 in radiation-induced pneumonitis, implicating the anti-inflammatory effects of bvPLA2 are dependent upon regulatory T cells. These results support the therapeutic potential of bvPLA2 in radiation pneumonitis and fibrosis treatments. PMID:27144583

  15. Regulatory T Cells Contribute to the Inhibition of Radiation-Induced Acute Lung Inflammation via Bee Venom Phospholipase A₂ in Mice.

    PubMed

    Shin, Dasom; Lee, Gihyun; Sohn, Sung-Hwa; Park, Soojin; Jung, Kyung-Hwa; Lee, Ji Min; Yang, Jieun; Cho, Jaeho; Bae, Hyunsu

    2016-01-01

    Bee venom has long been used to treat various inflammatory diseases, such as rheumatoid arthritis and multiple sclerosis. Previously, we reported that bee venom phospholipase A₂ (bvPLA₂) has an anti-inflammatory effect through the induction of regulatory T cells. Radiotherapy is a common anti-cancer method, but often causes adverse effects, such as inflammation. This study was conducted to evaluate the protective effects of bvPLA₂ in radiation-induced acute lung inflammation. Mice were focally irradiated with 75 Gy of X-rays in the lung and administered bvPLA₂ six times after radiation. To evaluate the level of inflammation, the number of immune cells, mRNA level of inflammatory cytokine, and histological changes in the lung were measured. BvPLA₂ treatment reduced the accumulation of immune cells, such as macrophages, neutrophils, lymphocytes, and eosinophils. In addition, bvPLA₂ treatment decreased inflammasome-, chemokine-, cytokine- and fibrosis-related genes' mRNA expression. The histological results also demonstrated the attenuating effect of bvPLA₂ on radiation-induced lung inflammation. Furthermore, regulatory T cell depletion abolished the therapeutic effects of bvPLA₂ in radiation-induced pneumonitis, implicating the anti-inflammatory effects of bvPLA₂ are dependent upon regulatory T cells. These results support the therapeutic potential of bvPLA₂ in radiation pneumonitis and fibrosis treatments. PMID:27144583

  16. Human regulatory T cells control TCR signaling and susceptibility to suppression in CD4+ T cells.

    PubMed

    Chellappa, Stalin; Lieske, Nora V; Hagness, Morten; Line, Pål D; Taskén, Kjetil; Aandahl, Einar M

    2016-07-01

    Human CD4(+)CD25(hi)FOXP3(+) regulatory T cells maintain immunologic tolerance and prevent autoimmune and inflammatory immune responses. Regulatory T cells undergo a similar activation cycle as conventional CD4(+) T cells upon antigen stimulation. Here, we demonstrate that T cell receptors and costimulation are required to activate the regulatory T cell suppressive function. Regulatory T cells suppressed the T cell receptor signaling in effector T cells in a time-dependent manner that corresponded with inhibition of cytokine production and proliferation. Modulation of the activation level and thereby the suppressive capacity of regulatory T cells imposed distinct T cell receptor signaling signatures and hyporesponsiveness in suppressed and proliferating effector T cells and established a threshold for effector T cell proliferation. The immune suppression of effector T cells was completely reversible upon removal of regulatory T cells. However, the strength of prior immune suppression by regulatory T cells and corresponding T cell receptor signaling in effector T cells determined the susceptibility to suppression upon later reexposure to regulatory T cells. These findings demonstrate how the strength of the regulatory T cell suppressive function determines intracellular signaling, immune responsiveness, and the later susceptibility of effector T cells to immune suppression and contribute to unveiling the complex interactions between regulatory T cells and effector T cells. PMID:26715685

  17. PDGF upregulates CLEC-2 to induce T regulatory cells

    PubMed Central

    Agrawal, Sudhanshu; Ganguly, Sreerupa; Hajian, Pega; Cao, Jia-Ning; Agrawal, Anshu

    2015-01-01

    The effect of platelet derived growth factor (PDGF) on immune cells is not elucidated. Here, we demonstrate PDGF inhibited the maturation of human DCs and induced IL-10 secretion. Culture of PDGF-DCs with T cells induced the polarization of T cells towards FoxP3 expressing T regulatory cells that secreted IL-10. Gene expression studies revealed that PDGF induced the expression of C-type lectin like receptor member 2, (CLEC-2) receptor on DCs. Furthermore, DCs transfected with CLEC-2 induced T regulatory cells in DC-T cell co-culture. CLEC-2 is naturally expressed on platelets. Therefore, to confirm whether CLEC-2 is responsible for inducing the T regulatory cells, T cells were cultured with either CLEC-2 expressing platelets or soluble CLEC-2. Both conditions resulted in the induction of regulatory T cells. The generation of T regulatory cells was probably due to the binding of CLEC-2 with its ligand podoplanin on T cells, since crosslinking of podoplanin on the T cells also resulted in the induction of T regulatory cells. These data demonstrate that PDGF upregulates the expression of CLEC-2 on cells to induce T regulatory cells. PMID:26416420

  18. Inhibition of Immunoglobulin E signals during allergen ingestion leads to reversal of established food allergy and induction of regulatory T cells

    PubMed Central

    Burton, Oliver T.; Noval-Rivas, Magali; Zhou, Joseph S.; Logsdon, Stephanie L.; Darling, Alanna R.; Koleoglou, Kyle J.; Roers, Axel; Houshyar, Hani; Crackower, Michael A.; Chatila, Talal A.; Oettgen, Hans C.

    2014-01-01

    SUMMARY Immunoglobulin E (IgE) antibodies are known for triggering immediate hypersensitivity reactions such as food anaphylaxis. In this study, we tested whether they might additionally function to amplify nascent antibody and T helper 2 (Th2) cell-mediated responses to ingested proteins and if blocking IgE would modify sensitization. Using mice harboring a disinhibited form of the IL-4 receptor, we developed an adjuvant-free model of peanut allergy. Mast cells and IgE were required for induction of antibody and Th2 cell-mediated responses to peanut ingestion and they impaired regulatory T (Treg) cell induction. Mast cell-targeted genetic deletion of the FcεRI signaling kinase, Syk, or Syk blockade also prevented peanut sensitization. In mice with established allergy, Syk blockade facilitated desensitization and induction of Treg cells, which suppressed allergy when transferred to naïve recipients. Our study suggests a key role for IgE in driving Th2 cell and IgE responses while suppressing Treg cells in food allergy. PMID:25017467

  19. Triptolide Inhibits Osteoclast Differentiation and Bone Resorption In Vitro via Enhancing the Production of IL-10 and TGF-β1 by Regulatory T Cells

    PubMed Central

    Xu, Huihui; Zhao, Hongyan; Wang, Gui; Huang, Jing; Guo, Minghui; Guo, Baosheng; Tan, Yong

    2016-01-01

    Triptolide, a purified component of Tripterygiumwilfordii Hook F, has been shown to have immunosuppressive and anti-inflammatory properties in rheumatoid arthritis (RA). Although triptolide has demonstrated that it could suppress bone destruction in collagen-induced mice, its therapeutic mechanism remains unclear. Many studies have investigated the effect of triptolide on Tregs and Tregs-related cytokine involved in RA. Additionally, previous studies have implied that Tregs inhibit osteoclast differentiation and bone resorption. Thus, in this study we aimed to explore the regulatory mechanism by which triptolide influences the Treg-mediated production of IL-10 and TGF-β1 to affect osteoclast differentiation and bone resorption. In cocultures system of Tregs and mouse bone marrow macrophages (BMMs), Tregs inhibited the differentiation of osteoclasts and reduced the resorbed areas significantly and the production of both IL-10 and TGF-β1 was upregulated. When the coculture systems were pretreated with triptolide, they produced higher levels of IL-10 and TGF-β1. Our data indicate that triptolide enhances the suppressive effects of Tregs on osteoclast differentiation and bone resorption by enhancing the secretion of IL-10 and TGF-β1. Tregs are most likely involved in the triptolide-mediated regulation of bone metabolism and may provide a potential therapeutic target for the treatment of inflammatory bone destruction. PMID:27413257

  20. Immunometabolism of regulatory T cells.

    PubMed

    Newton, Ryan; Priyadharshini, Bhavana; Turka, Laurence A

    2016-05-19

    The bidirectional interaction between the immune system and whole-body metabolism has been well recognized for many years. Via effects on adipocytes and hepatocytes, immune cells can modulate whole-body metabolism (in metabolic syndromes such as type 2 diabetes and obesity) and, reciprocally, host nutrition and commensal-microbiota-derived metabolites modulate immunological homeostasis. Studies demonstrating the metabolic similarities of proliferating immune cells and cancer cells have helped give birth to the new field of immunometabolism, which focuses on how the cell-intrinsic metabolic properties of lymphocytes and macrophages can themselves dictate the fate and function of the cells and eventually shape an immune response. We focus on this aspect here, particularly as it relates to regulatory T cells. PMID:27196520

  1. Immunometabolism of regulatory T cells

    PubMed Central

    Newton, Ryan; Priyadharshini, Bhavana; Turka, Laurence A

    2016-01-01

    The bidirectional interaction between the immune system and whole-body metabolism has been well recognized for many years. Via effects on adipocytes and hepatocytes, immune cells can modulate whole-body metabolism (in metabolic syndromes such as type 2 diabetes and obesity) and, reciprocally, host nutrition and commensal-microbiota-derived metabolites modulate immunological homeostasis. Studies demonstrating the metabolic similarities of proliferating immune cells and cancer cells have helped give birth to the new field of immunometabolism, which focuses on how the cell-intrinsic metabolic properties of lymphocytes and macrophages can themselves dictate the fate and function of the cells and eventually shape an immune response. We focus on this aspect here, particularly as it relates to regulatory T cells. PMID:27196520

  2. The potential role of functional inhibition of T regulatory cells by anti-TGFβ antibody in photodynamic therapy of renal cancer

    NASA Astrophysics Data System (ADS)

    Mroz, Pawel; Hamblin, Michael R.

    2011-03-01

    Photodynamic therapy (PDT) has been shown to be an effective locally ablative anti-cancer treatment that has the additional advantage of inducing tumor-directed immune response. We hypothesized that PDT could be combined with anti-transforming growth factor (TGF) beta antibody that does not significantly affect the population of cytotoxic T lymphocytes (CTL) but at the same time, has the potential to decrease the immunosuppressive effects of regulatory T-cells (Treg) mediated by TGF beta. This hypothesis was tested with aTGF-beta antibody combined with BPD-mediated PDT in a BALB/c renal cell carcinoma model. Evidence of positive benefits of the combination therapy over individual treatments alone was obtained.

  3. Regulatory T cells: stability revisited

    PubMed Central

    Bailey-Bucktrout, Samantha L.; Bluestone, Jeffrey A.

    2011-01-01

    Breakdown in self-tolerance is due, in part, to a loss of regulatory T (Treg) cells. Recently, a controversy has surfaced about whether Treg cells are overwhelmingly stable, or if they can be reprogrammed in inflammatory and autoimmune environments. Those in the instability “camp” have shown that a fraction of Treg cells lose Foxp3 and acquire effector arm activities. Instability is coupled with IL-2 insufficiency and the inflammatory milieu that promote reprogramming. Here, we highlight the basic tenets of each viewpoint and discuss technical, biological and environmental differences in the models that may help yield a unifying hypothesis. Also considered is how Treg cell instability could link to development of autoimmune disease and the implications for Treg cell-based cellular therapy trials. PMID:21620768

  4. Inhibition of NF-κB by a PXR-dependent pathway mediates counter-regulatory activities of rifaximin on innate immunity in intestinal epithelial cells.

    PubMed

    Mencarelli, Andrea; Renga, Barbara; Palladino, Giuseppe; Claudio, D'Amore; Ricci, Patrizia; Distrutti, Eleonora; Barbanti, Miriam; Baldelli, Franco; Fiorucci, Stefano

    2011-10-01

    A dysregulated interaction between intestinal epithelial cells (IEC) and components of innate immunity is a hallmark of inflammatory bowel diseases. Rifaximin is a poorly absorbed oral antimicrobial agent increasingly used in the treatment of inflammatory bowel diseases that has been demonstrated to act as a gut-specific ligand for the human nuclear receptor pregnane-X receptor (PXR). In the present study we investigated, whether activation of PXR in IEC by rifaximin, emanates counter-regulatory signals and modulates the expression of cytokines or chemokines mechanistically involved in dysregulated intestinal immune homeostasis documented in inflammatory bowel diseases. Our results demonstrate that primary IEC express PXR that regulate the pattern of cytokines and chemokines expressed. PXR silencing decreases TGF-β and IP-10 while increases the expression of TNF-α, IL-8, Rantes and increase the production of PGE2. This pattern is further exacerbated by treating anti-PXR siRNA cells with bacterial endotoxin (LPS). Exposure to rifaximin caused a robust attenuation of generation of inflammatory mediators caused by LPS and increased the generation of TGF-β. PXR silencing completely abrogated these anti-inflammatory effects of rifaximin. By Western blot analysis we found that rifaximin abrogates the binding of NF-κB caused by LPS. Finally, exposure of human colon biopsies from inflammatory bowel diseases patients to rifaximin reduced mRNA levels of IL-8, Rantes, MIP-3α and TNFα induced by LPS. Collectively, these data establish that rifaximin exerts counter-regulatory activities at the interface between enteric bacteria and intestinal epithelial cells. The ability of rifaximin to activate PXR contributes to the maintenance of the intestinal immune homeostasis. PMID:21806984

  5. TLR2 dependent induction of vitamin A metabolizing enzymes in dendritic cells promotes T regulatory responses and inhibits TH-17 mediated autoimmunity

    PubMed Central

    Manicassamy, Santhakumar; Ravindran, Rajesh; Deng, Jiusheng; Oluoch, Herold; Denning, Timothy L; Kasturi, Sudhir Pai; Rosenthal, Kristen M.; Evavold, Brian D.; Pulendran, Bali

    2009-01-01

    Immune sensing of a microbe occurs via multiple receptors. How signals from different receptors are coordinated to yield a specific immune response is poorly understood. We demonstrate that the different pathogen recognition receptors, TLR2 and dectin-1, recognizing the same microbial stimulus, stimulate distinct innate and adaptive responses. TLR2 signaling induced splenic dendritic cells (DCs) to express the retinoic acid (RA) metabolizing enzyme Raldh2 and IL-10, and to metabolize vitamin A and stimulate Foxp3+ T regulatory cells (Treg cells). RA acted on DCs to induce Socs3 expression, which suppressed activation of p38 MAPK and pro-inflammatory cytokines. Consistent with this, TLR2 signaling induced Treg cells, and suppressed IL-23 and TH-17/ TH-1 mediated autoimmune responses in vivo. In contrast, dectin-1 signaling mostly induced IL-23 and pro-inflammatory cytokines, and augmented TH-17/ TH-1 mediated autoimmune responses in vivo. These data define a new mechanism for the systemic induction of RA and immune suppression against autoimmunity. PMID:19252500

  6. Toll-like receptor 2-dependent induction of vitamin A-metabolizing enzymes in dendritic cells promotes T regulatory responses and inhibits autoimmunity.

    PubMed

    Manicassamy, Santhakumar; Ravindran, Rajesh; Deng, Jiusheng; Oluoch, Herold; Denning, Timothy L; Kasturi, Sudhir Pai; Rosenthal, Kristen M; Evavold, Brian D; Pulendran, Bali

    2009-04-01

    Immune sensing of a microbe occurs via multiple receptors. How signals from different receptors are coordinated to yield a specific immune response is poorly understood. We show that two pathogen recognition receptors, Toll-like receptor 2 (TLR2) and dectin-1, recognizing the same microbial stimulus, stimulate distinct innate and adaptive responses. TLR2 signaling induced splenic dendritic cells (DCs) to express the retinoic acid metabolizing enzyme retinaldehyde dehydrogenase type 2 and interleukin-10 (IL-10) and to metabolize vitamin A and stimulate Foxp3(+) T regulatory cells (T(reg) cells). Retinoic acid acted on DCs to induce suppressor of cytokine signaling-3 expression, which suppressed activation of p38 mitogen-activated protein kinase and proinflammatory cytokines. Consistent with this finding, TLR2 signaling induced T(reg) cells and suppressed IL-23 and T helper type 17 (T(H)17) and T(H)1-mediated autoimmune responses in vivo. In contrast, dectin-1 signaling mostly induced IL-23 and proinflammatory cytokines and augmented T(H)17 and T(H)1-mediated autoimmune responses in vivo. These data define a new mechanism for the systemic induction of retinoic acid and immune suppression against autoimmunity. PMID:19252500

  7. Epigallocatechin-3-gallate inhibits expression of receptors for T cell regulatory cytokines and their downstream signaling in mouse CD4+ T cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We previously showed a suppressive effect of epigallocatechin-3-gallate (EGCG) on T cell cycling and expansion as well as a paradoxical effect on IL-2 levels (up-regulating) and IL-2 receptor (IL-2R)alpha expression (down-regulating). Thus, in the current study we tested the hypothesis that EGCG aff...

  8. Therapeutic effect of ghrelin in experimental autoimmune encephalomyelitis by inhibiting antigen-specific Th1/Th17 responses and inducing regulatory T cells.

    PubMed

    Souza-Moreira, Luciana; Delgado-Maroto, Virginia; Morell, Maria; O'Valle, Francisco; Del Moral, Raimundo G; Gonzalez-Rey, Elena

    2013-05-01

    Ghrelin is an important gastrointestinal hormone that regulates feeding and metabolism. Moreover, ghrelin is produced by immune cells and shows potent anti-inflammatory activities. Here, we investigated its effect in two models of experimental autoimmune encephalomyelitis (EAE) that mirror chronic and relapsing-remitting multiple sclerosis. A short systemic treatment with ghrelin after the disease onset reduced clinical severity and incidence of both forms of EAE, which was associated with a decrease in inflammatory infiltrates in spinal cord and in the subsequent demyelination. This therapeutic effect was exerted through the reduction of the autoimmune and inflammatory components of the disease. Ghrelin decreased the presence/activation of encephalitogenic Th1 and Th17 cells in periphery and nervous system, down-regulated various inflammatory mediators, and induced regulatory T cells. In summary, our findings provide a powerful rationale for the assessment of the efficacy of ghrelin as a novel therapeutic approach for treating multiple sclerosis through distinct immunomodulatory mechanisms and further support the concept that the neuroendocrine and immune systems crosstalk to finely tune the final immune response of our body. PMID:23376169

  9. p53-dependent inhibition of mammalian cell survival by a genetically selected peptide aptamer that targets the regulatory subunit of protein kinase CK2.

    PubMed

    Martel, V; Filhol, O; Colas, P; Cochet, C

    2006-11-30

    Based on the perturbation of its expression in human cancers and on its involvement in transformation and tumorigenesis, protein kinase CK2 has recently attracted attention as a potential therapeutic target. To assess the value of CK2 as a target for antiproliferative strategies, we have initiated a program aiming to develop inhibitors targeting specifically the regulatory CK2beta subunit. Here, we use a two-hybrid approach to isolate from combinatorial libraries, peptide aptamers that specifically interact with CK2beta. One of these (P1), which has significant sequence homology to the cytomegalovirus IE2 protein, binds with high affinity to the N-terminal domain of CK2beta without disrupting the formation of the CK2 holoenzyme. Expression of green fluorescent protein (GFP)-P1 in different mammalian cell lines activates p53 phosphorylation on serine 15, induces an upregulation of p21 and the release of the Cyt-C and apoptosis-inducing factor proapoptotic proteins triggering caspase-dependent and caspase-independent apoptosis. GFP-P1-induced apoptosis is associated with a p53-dependent pathway as cell death was abrogated in p53 knocked out cells. In summary, our data show that genetically selected peptide aptamers that specifically target CK2beta can induce apoptosis in mammalian cells through the recruitment of a p53-dependent apoptosis pathway. They also emphasize the critical role of CK2beta for cell survival and might allow the design of novel proapoptotic agents targeting this protein. PMID:16751801

  10. Intranasal immunization with heat shock protein 60 induces CD4(+) CD25(+) GARP(+) and type 1 regulatory T cells and inhibits early atherosclerosis.

    PubMed

    Zhong, Y; Tang, H; Wang, X; Zeng, Q; Liu, Y; Zhao, X I; Yu, K; Shi, H; Zhu, R; Mao, X

    2016-03-01

    Atherosclerosis is an autoimmune inflammatory disease involving both innate and adaptive immune mechanisms. Immune tolerance induction may have therapeutic potential for the suppression of atherosclerosis. Current interest is directed towards mucosal tolerance induction, especially nasal tolerance. Previous studies have shown that heat shock protein 60 (HSP60) is recognized as an important autoantigen in atherosclerosis, and nasal or oral HSP60 can induce tolerance and ameliorate atherosclerosis by inducing several subsets of regulatory T cells (Tregs ) such as latency-associated peptide (LAP)(+) and forkhead box transcription factor 3 (FoxP3)(+) Tregs. However, little is known regarding the detailed mechanisms of nasal tolerance. Here, we again investigated the impact of nasal HSP60 on atherosclerosis and the mechanisms underlying the anti-atherosclerosis responses. We found that nasal HSP60 caused a significant 33·6% reduction in plaque size at the aortic root in the early stages of atherosclerosis (P < 0·001). Notably, a significant increase in activated CD4(+) CD25(+) glycoprotein A repetitions predominant (GARP)(+) Tregs, type 1 Tregs (Tr1 cells), and CD4(+) CD25(+) FoxP3(+) Tregs, as well as a marked decrease in the numbers of type 1 and 17 T helper cells was detected in the spleens and cervical lymph nodes of HSP60-treated mice. Moreover, nasal HSP60 increases the production of transforming growth factor (TGF)-β and interleukin (IL)-10 and decreases the secretion of IFN-γ and IL-17. Interestingly, the atheroprotective role of nasal HSP60 treatment was abrogated partly by the neutralization of IL-10. Our findings show that nasal administration of HSP60 can attenuate atherosclerotic formation by inducing GARP(+) Tregs, Tr1 cells and FoxP3(+) Tregs, and that these Tregs maintain immune homeostasis by secreting IL-10 and TGF-β. PMID:26452441

  11. Inhibition of the JAK/STAT Signaling Pathway in Regulatory T Cells Reveals a Very Dynamic Regulation of Foxp3 Expression

    PubMed Central

    Goldstein, Jérémie D.; Burlion, Aude; Zaragoza, Bruno; Sendeyo, Kélhia; Polansky, Julia K.; Huehn, Jochen; Piaggio, Eliane; Salomon, Benoit L.

    2016-01-01

    The IL-2/JAK3/STAT-5 signaling pathway is involved on the initiation and maintenance of the transcription factor Foxp3 in regulatory T cells (Treg) and has been associated with demethylation of the intronic Conserved Non Coding Sequence-2 (CNS2). However, the role of the JAK/STAT pathway in controlling Foxp3 in the short term has been poorly investigated. Using two different JAK/STAT pharmacological inhibitors, we observed a detectable loss of Foxp3 after 10 min. of treatment that affected 70% of the cells after one hour. Using cycloheximide, a general inhibitor of mRNA translation, we determined that Foxp3, but not CD25, has a high turnover in IL-2 stimulated Treg. This reduction was correlated with a rapid reduction of Foxp3 mRNA. This loss of Foxp3 was associated with a loss in STAT-5 binding to the CNS2, which however remains demethylated. Consequently, Foxp3 expression returns to normal level upon restoration of basal JAK/STAT signaling in vivo. Reduced expression of several genes defining Treg identity was also observed upon treatment. Thus, our results demonstrate that Foxp3 has a rapid turn over in Treg partly controlled at the transcriptional level by the JAK/STAT pathway. PMID:27077371

  12. Inhibition of mTOR complex 2 induces GSK3/FBXW7-dependent degradation of sterol regulatory element-binding protein 1 (SREBP1) and suppresses lipogenesis in cancer cells

    PubMed Central

    Li, Shaohua; Oh, You-Take; Yue, Ping; Khuri, Fadlo R.; Sun, Shi-Yong

    2015-01-01

    Cancer cells feature increased de novo lipogenesis. Sterol regulatory element-binding protein 1 (SREBP1), when presented in its mature form (mSREBP1), enhances lipogenesis through increasing transcription of several of its target genes. Mammalian target of rapamycin (mTOR) complexes, mTORC1 and mTORC2, are master regulators of cellular survival, growth and metabolism. A role for mTORC1 in the regulation of SREBP1 activity has been suggested; however the connection between mTORC2 and SREBP1 has not been clearly established and hence is the focus of this study. mTOR kinase inhibitors (e.g., INK128), which inhibit both mTORC1 and mTORC2, decreased mSREBP1 levels in various cancer cell lines. Knockdown of rictor, but not raptor, also decreased mSREBP1. Consistently, reduced mSREBP1 levels were detected in cells deficient in rictor or Sin1 compared to parent or rictor-deficient cells with re-expression of ectopic rictor. Hence it is mTORC2 inhibition that causes mSREBP1 reduction. As a result, expression of the mSREBP1 target genes acetyl-CoA carboxylase and fatty acid synthase was suppressed, accompanied with suppressed lipogenesis in cells exposed to INK128. Moreover, mSREBP1 stability was reduced in cells treated with INK128 or rictor knockdown. Inhibition of proteasome, GSK3 or the E3 ubiquitin ligase, FBXW7, prevented mSREBP1 reduction induced by mTORC2 inhibition. Thus mTORC2 inhibition clearly facilitates GSK3-dependent, FBXW7-mediated mSREBP1 degradation, leading to mSREBP1 reduction. Accordingly, we conclude that mTORC2 positively regulates mSREBP1 stability and lipogenesis. Our findings reveal a novel biological function of mTORC2 in the regulation of lipogenesis and warrant further study in this direction. PMID:25893295

  13. Inhibition of mTOR complex 2 induces GSK3/FBXW7-dependent degradation of sterol regulatory element-binding protein 1 (SREBP1) and suppresses lipogenesis in cancer cells.

    PubMed

    Li, S; Oh, Y-T; Yue, P; Khuri, F R; Sun, S-Y

    2016-02-01

    Cancer cells feature increased de novo lipogenesis. Sterol regulatory element-binding protein 1 (SREBP1), when presented in its mature form (mSREBP1), enhances lipogenesis by increasing transcription of several of its target genes. Mammalian target of rapamycin (mTOR) complexes, mTORC1 and mTORC2, are master regulators of cellular survival, growth and metabolism. A role for mTORC1 in the regulation of SREBP1 activity has been suggested; however, the connection between mTORC2 and SREBP1 has not been clearly established and hence is the focus of this study. mTOR kinase inhibitors (for example, INK128), which inhibit both mTORC1 and mTORC2, decreased mSREBP1 levels in various cancer cell lines. Knockdown of rictor, but not raptor, also decreased mSREBP1. Consistently, reduced mSREBP1 levels were detected in cells deficient in rictor or Sin1 compared with parent or rictor-deficient cells with re-expression of ectopic rictor. Hence it is mTORC2 inhibition that causes mSREBP1 reduction. As a result, expression of the mSREBP1 target genes acetyl-CoA carboxylase and fatty-acid synthase was suppressed, along with suppressed lipogenesis in cells exposed to INK128. Moreover, mSREBP1 stability was reduced in cells treated with INK128 or rictor knockdown. Inhibition of proteasome, GSK3 or the E3 ubiquitin ligase, FBXW7, prevented mSREBP1 reduction induced by mTORC2 inhibition. Thus mTORC2 inhibition clearly facilitates GSK3-dependent, FBXW7-mediated mSREBP1 degradation, leading to mSREBP1 reduction. Accordingly, we conclude that mTORC2 positively regulates mSREBP1 stability and lipogenesis. Our findings reveal a novel biological function of mTORC2 in the regulation of lipogenesis and warrant further study in this direction. PMID:25893295

  14. Generation of regulatory dendritic cells after treatment with paeoniflorin.

    PubMed

    Chen, Dan; Li, Yingxi; Wang, Xiaodong; Li, Keqiu; Jing, Yaqing; He, Jinghua; Qiang, Zhaoyan; Tong, Jingzhi; Sun, Ke; Ding, Wen; Kang, Yi; Li, Guang

    2016-08-01

    Regulatory dendritic cells are a potential therapeutic tool for assessing a variety of immune overreaction diseases. Paeoniflorin, a bioactive glucoside extracted from the Chinese herb white paeony root, has been shown to be effective at inhibiting the maturation and immunostimulatory function of murine bone marrow-derived dendritic cells. However, whether paeoniflorin can program conventional dendritic cells toward regulatory dendritic cells and the underlying mechanism remain unknown. Here, our study demonstrates that paeoniflorin can induce the production of regulatory dendritic cells from human peripheral blood monocyte-derived immature dendritic cells in the absence or presence of lipopolysaccharide (LPS) but not from mature dendritic cells, thereby demonstrating the potential of paeoniflorin as a specific immunosuppressive drug with fewer complications and side effects. These regulatory dendritic cells treated with paeoniflorin exhibited high CD11b/c and low CD80, CD86 and CD40 expression levels as well as enhanced abilities to capture antigen and promote the proliferation of CD4(+)CD25(+) T cells and reduced abilities to migrate and promote the proliferation of CD4(+) T cells, which is associated with the upregulation of endogenous transforming growth factor (TGF)-β-mediated indoleamine 2,3-dioxygenase (IDO) expression. Collectively, paeoniflorin could program immature dendritic cells (imDCs) and imDCs stimulated with LPS toward a regulatory DC fate by upregulating the endogenous TGF-β-mediated IDO expression level, thereby demonstrating its potential as a specific immunosuppressive drug. PMID:26721806

  15. Tumor Progression Locus 2 (Tpl2) Activates the Mammalian Target of Rapamycin (mTOR) Pathway, Inhibits Forkhead Box P3 (FoxP3) Expression, and Limits Regulatory T Cell (Treg) Immunosuppressive Functions.

    PubMed

    Li, Xin; Acuff, Nicole V; Peeks, Angela R; Kirkland, Rebecca; Wyatt, Kara D; Nagy, Tamas; Watford, Wendy T

    2016-08-01

    The serine/threonine kinase tumor progression locus 2 (Tpl2, also known as Map3k8/Cot) is a potent inflammatory mediator that drives the production of TNFα, IL-1β, and IFNγ. We previously demonstrated that Tpl2 regulates T cell receptor (TCR) signaling and modulates T helper cell differentiation. However, very little is known about how Tpl2 modulates the development of regulatory T cells (Tregs). Tregs are a specialized subset of T cells that express FoxP3 and possess immunosuppressive properties to limit excess inflammation. Because of the documented role of Tpl2 in promoting inflammation, we hypothesized that Tpl2 antagonizes Treg development and immunosuppressive function. Here we demonstrate that Tpl2 constrains the development of inducible Tregs. Tpl2(-/-) naïve CD4(+) T cells preferentially develop into FoxP3(+) inducible Tregs in vitro as well as in vivo in a murine model of ovalbumin (OVA)-induced systemic tolerance. Treg biasing of Tpl2(-/-) T cells depended on TCR signal strength and corresponded with reduced activation of the mammalian target of rapamycin (mTOR) pathway. Importantly, Tpl2(-/-) Tregs have basally increased expression of FoxP3 and immunosuppressive molecules, IL-10 and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). Furthermore, they were more immunosuppressive in vivo in a T cell transfer model of colitis, as evidenced by reduced effector T cell accumulation, systemic production of inflammatory cytokines, and colonic inflammation. These results demonstrate that Tpl2 promotes inflammation in part by constraining FoxP3 expression and Treg immunosuppressive functions. Overall, these findings suggest that Tpl2 inhibition could be used to preferentially drive Treg induction and thereby limit inflammation in a variety of autoimmune diseases. PMID:27261457

  16. The regulatory niche of intestinal stem cells.

    PubMed

    Sailaja, Badi Sri; He, Xi C; Li, Linheng

    2016-09-01

    The niche constitutes a unique category of cells that support the microenvironment for the maintenance and self-renewal of stem cells. Intestinal stem cells reside at the base of the crypt, which contains adjacent epithelial cells, stromal cells and smooth muscle cells, and soluble and cell-associated growth and differentiation factors. We summarize here recent advances in our understanding of the crucial role of the niche in regulating stem cells. The stem cell niche maintains a balance among quiescence, proliferation and regeneration of intestinal stem cells after injury. Mesenchymal cells, Paneth cells, immune cells, endothelial cells and neural cells are important regulatory components that secrete niche ligands, growth factors and cytokines. Intestinal homeostasis is regulated by niche signalling pathways, specifically Wnt, bone morphogenetic protein, Notch and epidermal growth factor. These insights into the regulatory stem cell niche during homeostasis and post-injury regeneration offer the potential to accelerate development of therapies for intestine-related disorders. PMID:27060879

  17. Ricin enhances IgE responses by inhibiting a subpopulation of early-activated IgE regulatory CD8+ T cells.

    PubMed Central

    Diaz-Sanchez, D; Lee, T H; Kemeny, D M

    1993-01-01

    Ricin, a toxic lectin from castor beans greatly enhances IgE responses to bee venom phospholipase A2 (PLA2) in high and low IgE responder strains of rat. The increase in IgE is accompanied by a 60% reduction in the number of CD8+ but not CD4+ T cells in the spleen. Optimal enhancement of IgE by ricin occurs when it is given at the same time as the antigen or 24 hr later, suggesting that it acts on cells which were activated as a consequence of immunization. Radio ligand-binding studies with 125I ricin were used to compare the number of ricin binding sites on CD4+ and CD8+ T cells. No difference was seen in either the affinity or the number of receptors for ricin on the CD4+ and CD8+ T cells of unimmunized rats. In contrast, CD8+ T cells taken from rats which had been immunized with 10 micrograms of PLA2 24 hr earlier demonstrated considerably more ricin receptors (3.9 x 10(7) +/- 2.2 x 10(6) binding sites/cell) than CD4+ T cells (3.19 x 10(6) +/- 1.08 x 10(6) binding sites/cell). However the affinity of the receptors for ricin was unchanged. Cytofluorographic analysis with fluorescein isothiocyanate (FITC)-labelled ricin confirmed these observations and indicated that increased ricin binding occurred on a subpopulation of CD8+ T cells. The effect of CD8+ T cells on IgE regulation was investigated by adoptive transfer. 1 x 10(8) highly purified (> 98%) splenic CD8+ T cells collected from Brown Norway rats 3 days after immunization with 10 micrograms of PLA2 were adoptively transferred to naive, syngeneic recipients. The IgE antibody response to PLA2 + A1(OH)3 seen in these animals was reduced by 91%. Adoptive transfer of CD4+ T cells from the same donor animals did not induce suppression and nor did adoptive transfer of CD8+ T cells from animals given both ricin and PLA2. However, when recipients of CD8+ T cells taken from rats immunized with PLA2 were immunized with a different antigen [ovalbumin (OVA)] and A1(OH)3 the IgE antibody response was also suppressed

  18. Regulatory T cells in spontaneous autoimmune encephalomyelitis.

    PubMed

    Furtado, G C; Olivares-Villagómez, D; Curotto de Lafaille, M A; Wensky, A K; Latkowski, J A; Lafaille, J J

    2001-08-01

    Spontaneous experimental autoimmune encephalomyelitis (EAE) develops in 100% of mice harboring a monoclonal myelin basic protein (MBP)-specific CD4+ alphabeta T-cell repertoire. Monoclonality of the alphabeta T-cell repertoire can be achieved by crossing MBP-specific T-cell receptor (TCR) transgenic mice with either RAG-/- mice or TCR alpha-/-/TCR beta-/- double knockout mice. Spontaneous EAE can be prevented by a single administration of purified CD4+ splenocytes or thymocytes obtained from wild-type syngeneic mice. The regulatory T cells (T-reg) that protect from spontaneous EAE need not express the CD25 marker, as effective protection can be attained with populations depleted of CD25+ T cells. Although the specificity of the regulatory T cells is important for their generation or regulatory function, T cells that protect from spontaneous EAE can have a diverse TCR alpha and beta chain composition. T-reg cells expand poorly in vivo, and appear to be long lived. Finally, precursors for T-reg are present in fetal liver as well as in the bone marrow of aging mice. We propose that protection of healthy individuals from autoimmune diseases involves several layers of regulation, which consist of CD4+CD25+ regulatory T cells, CD4+CD25- T-reg cells, and anti-TCR T cells, with each layer potentially operating at different stages of T-helper cell-mediated immune responses. PMID:11722629

  19. Regulatory T Cells: A Crisis Averted.

    PubMed

    Malhotra, Deepali; Jenkins, Marc K

    2016-05-17

    Although regulatorycells protect people from autoimmunity, two recent papers in Immunity (Malchow et al., 2016; Kieback et al., 2016) demonstrate that these cells are also a crisis averted. Without the proper education in the thymus, these cells will turn on their host and cause autoimmunity. PMID:27192571

  20. Soy milk digestion extract inhibits progression of prostate cancer cell growth via regulation of prostate cancer‑specific antigen and cell cycle-regulatory genes in human LNCaP cancer cells.

    PubMed

    Kang, Nam-Hee; Shin, Hee-Chang; Oh, Seunghyun; Lee, Kyun-Hee; Lee, Yoon-Bok; Choi, Kyung-Chul

    2016-08-01

    Soy milk, which is produced from whole soybeans, contains a variety of biologically active components. Isoflavones are a class of soy-derived phytoestrogens with beneficial effects, among which genistein (GEN) has been previously indicated to reduce the risk of prostate cancer. The present study evaluated the effects of soy milk digestion extract (SMD) on the progression of prostate cancer via the estrogen receptor (ER)β in human LNCaP prostate cancer cells. To evaluate the effects of SMD (daizein, 1.988 mg/100g, glycitein, 23.537 mg/100 g and GEN, 0.685 mg/100g) on cell proliferation, LNCaP cells were cultured in media containing vehicle (0.1% dimethyl sulfoxide), 17β‑estradiol (E2; 2.7x10‑7 mg/ml), GEN (2.7x10-2 mg/ml) of SMD (total aglycon concentration, 0.79 mg/ml), after which the cell viability was examined using an MTT assay. The cell viability was significantly elevated by E2 (by 45±0.18%), while it was markedly reduced by GEN (73.2±0.03%) or SMD (74.8±0.09%). Semi‑quantitative reverse transcription polymerase chain reaction analysis was performed to assess the mRNA expression levels of target genes, including ERβ, prostate cancer‑specific antigen (PSA) and cell cycle regulators p21, Cyclin D1 and cyclin-dependent kinase (CDK)4. The expression of ERβ was almost completely diminished by E2, whereas it was significantly elevated by SMD. In addition, the expression levels of PSA were considerably reduced by SMD. The expression of p21 was significantly elevated by SMD, while it was markedly reduced by E2. Of note, the expression levels of Cyclin D1 and CDK4 were considerably elevated by E2, while being significantly reduced by GEN and SMD. All of these results indicated that SMD may inhibit the proliferation of human prostate cancer cells via regulating the expression of ERβ, PSA, p21, Cyclin D1 and CDK4 in an ER-dependent manner. PMID:27315510

  1. Activation of Interferon Regulatory Factor 3 Is Inhibited by the Influenza A Virus NS1 Protein

    PubMed Central

    Talon, Julie; Horvath, Curt M.; Polley, Rosalind; Basler, Christopher F.; Muster, Thomas; Palese, Peter; García-Sastre, Adolfo

    2000-01-01

    We present a novel mechanism by which viruses may inhibit the alpha/beta interferon (IFN-α/β) cascade. The double-stranded RNA (dsRNA) binding protein NS1 of influenza virus is shown to prevent the potent antiviral interferon response by inhibiting the activation of interferon regulatory factor 3 (IRF-3), a key regulator of IFN-α/β gene expression. IRF-3 activation and, as a consequence, IFN-β mRNA induction are inhibited in wild-type (PR8) influenza virus-infected cells but not in cells infected with an isogenic virus lacking the NS1 gene (delNS1 virus). Furthermore, NS1 is shown to be a general inhibitor of the interferon signaling pathway. Inhibition of IRF-3 activation can be achieved by the expression of wild-type NS1 in trans, not only in delNS1 virus-infected cells but also in cells infected with a heterologous RNA virus (Newcastle disease virus). We propose that inhibition of IRF-3 activation by a dsRNA binding protein significantly contributes to the virulence of influenza A viruses and possibly to that of other viruses. PMID:10933707

  2. Cancer-Associated Myeloid Regulatory Cells.

    PubMed

    De Vlaeminck, Yannick; González-Rascón, Anna; Goyvaerts, Cleo; Breckpot, Karine

    2016-01-01

    Myeloid cells are critically involved in the pathophysiology of cancers. In the tumor microenvironment (TME), they comprise tumor-associated macrophages (TAMs), neutrophils (TANs), dendritic cells, and myeloid-derived suppressor cells, which are further subdivided into a monocytic subset and a granulocytic subset. Some of these myeloid cells, in particular TAMs and TANs, are divided into type 1 or type 2 cells, according to the paradigm of T helper type 1 or type 2 cells. Type 1-activated cells are generally characterized as cells that aid tumor rejection, while all other myeloid cells are shown to favor tumor progression. Moreover, these cells are often at the basis of resistance to various therapies. Much research has been devoted to study the biology of myeloid cells. This endeavor has proven to be challenging, as the markers used to categorize myeloid cells in the TME are not restricted to particular subsets. Also from a functional and metabolic point of view, myeloid cells share many features. Finally, myeloid cells are endowed with a certain level of plasticity, which further complicates studying them outside their environment. In this article, we challenge the exclusive use of cell markers to unambiguously identify myeloid cell subsets in the TME. We further propose to divide myeloid cells into myeloid regulatory or stimulatory cells according to their pro- or antitumor function, because we contend that for therapeutic purposes it is not targeting the cell subsets but rather targeting their protumor traits; hence, myeloid regulatory cells will push antitumor immunotherapy to the next level. PMID:27065074

  3. Cancer-Associated Myeloid Regulatory Cells

    PubMed Central

    De Vlaeminck, Yannick; González-Rascón, Anna; Goyvaerts, Cleo; Breckpot, Karine

    2016-01-01

    Myeloid cells are critically involved in the pathophysiology of cancers. In the tumor microenvironment (TME), they comprise tumor-associated macrophages (TAMs), neutrophils (TANs), dendritic cells, and myeloid-derived suppressor cells, which are further subdivided into a monocytic subset and a granulocytic subset. Some of these myeloid cells, in particular TAMs and TANs, are divided into type 1 or type 2 cells, according to the paradigm of T helper type 1 or type 2 cells. Type 1-activated cells are generally characterized as cells that aid tumor rejection, while all other myeloid cells are shown to favor tumor progression. Moreover, these cells are often at the basis of resistance to various therapies. Much research has been devoted to study the biology of myeloid cells. This endeavor has proven to be challenging, as the markers used to categorize myeloid cells in the TME are not restricted to particular subsets. Also from a functional and metabolic point of view, myeloid cells share many features. Finally, myeloid cells are endowed with a certain level of plasticity, which further complicates studying them outside their environment. In this article, we challenge the exclusive use of cell markers to unambiguously identify myeloid cell subsets in the TME. We further propose to divide myeloid cells into myeloid regulatory or stimulatory cells according to their pro- or antitumor function, because we contend that for therapeutic purposes it is not targeting the cell subsets but rather targeting their protumor traits; hence, myeloid regulatory cells will push antitumor immunotherapy to the next level. PMID:27065074

  4. Control of regulatory T cells and airway tolerance by lung macrophages and dendritic cells.

    PubMed

    Duan, Wei; Croft, Michael

    2014-12-01

    Airway tolerance, a state of immunological surveillance, suppresses the development of lung inflammatory disorders that are driven by various pathological effector cells of the immune system. Tolerance in the lung to inhaled antigens is primarily mediated by regulatory T cells (Treg cells) that can inhibit effector T cells via a myriad of mechanisms. Accumulating evidence suggests that regulatory antigen-presenting cells are critical for generating Treg cells and/or maintaining the suppressive environment in the lung. This review focuses on the control of airway tolerance by Treg cells and the role of regulatory lung tissue and alveolar macrophages, and lung and lymph node dendritic cells, in contributing to airway tolerance that is associated with suppression of allergic asthmatic disease. PMID:25525738

  5. Is there a feudal hierarchy amongst regulatory immune cells? More than just Tregs

    PubMed Central

    Mauri, Claudia; Carter, Natalie

    2009-01-01

    Nature has provided the developing immune system with several checkpoints important for the maintenance of tolerance and the prevention of autoimmunity. The regulatory mechanisms operating in the periphery of the system are mediated by subsets of regulatory cells, now considered principal contributors to peripheral tolerance. Regulatory T cells (Tregs) have received titanic interest in the past decade, placing them at the centre of immuno-suppressive reactions. However, it has become clearer that other immune suppressive cells inhibit auto-reactivity as effectively as Tregs. The function of Tregs and other regulatory cells in rheumatoid arthritis will be discussed in this review. PMID:19664198

  6. BET bromodomain inhibition releases the Mediator complex from select cis-regulatory elements

    PubMed Central

    Bhagwat, Anand S.; Roe, Jae-Seok; Mok, Beverly A.; Hohmann, Anja F.; Shi, Junwei; Vakoc, Christopher R.

    2016-01-01

    The bromodomain and extraterminal (BET) protein BRD4 can physically interact with the Mediator complex, but the relevance of this association to the therapeutic effects of BET inhibitors in cancer is unclear. Here, we show that BET inhibition causes a rapid release of Mediator from a subset of cis-regulatory elements in the genome of acute myeloid leukemia (AML) cells. These sites of Mediator eviction were highly correlated with transcriptional suppression of neighboring genes, which are enriched for targets of the transcription factor MYB and for functions related to leukemogenesis. An shRNA screen of Mediator in AML cells identified the MED12, MED13, MED23, and MED24 subunits as performing a similar regulatory function to BRD4 in this context, including a shared role in sustaining a block in myeloid maturation. These findings suggest that the interaction between BRD4 and Mediator has functional importance for gene-specific transcriptional activation and for AML maintenance. PMID:27068464

  7. Tolerogenic Dendritic Cells for Regulatory T Cell Induction in Man

    PubMed Central

    Raker, Verena K.; Domogalla, Matthias P.; Steinbrink, Kerstin

    2015-01-01

    Dendritic cells (DCs) are highly specialized professional antigen-presenting cells that regulate immune responses, maintaining the balance between tolerance and immunity. Mechanisms via which they can promote central and peripheral tolerance include clonal deletion, the inhibition of memory T cell responses, T cell anergy, and induction of regulatory T cells (Tregs). These properties have led to the analysis of human tolerogenic DCs as a therapeutic strategy for the induction or re-establishment of tolerance. In recent years, numerous protocols for the generation of human tolerogenic DCs have been developed and their tolerogenic mechanisms, including induction of Tregs, are relatively well understood. Phase I trials have been conducted in autoimmune disease, with results that emphasize the feasibility and safety of treatments with tolerogenic DCs. Therefore, the scientific rationale for the use of tolerogenic DCs therapy in the fields of transplantation medicine and allergic and autoimmune diseases is strong. This review will give an overview on efforts and protocols to generate human tolerogenic DCs with focus on IL-10-modulated DCs as inducers of Tregs and discuss their clinical applications and challenges faced in further developing this form of immunotherapy. PMID:26617604

  8. Epigallocatechin-3-gallate-induced inhibition of interleukin-6 release and adjustment of the regulatory T/T helper 17 cell balance in the treatment of colitis in mice

    PubMed Central

    XU, ZHENGLEI; WEI, CHENG; ZHANG, RU; YAO, JUN; ZHANG, DINGUO; WANG, LISHENG

    2015-01-01

    Epigallocatechin-3-gallate (EGCG) has a promising therapeutic effect for ulcerative colitis (UC), but the treatment mechanism has yet to be fully elucidated. The aim of the present study was to investigate the mechanism of EGCG in the treatment of UC. Experimental colitis mouse models were prepared. The mice were randomly divided into four groups: Normal control, model (MD), 50 mg/kg/day EGCG treatment and 100 mg/kg/day EGCG treatment. The daily disease activity index (DAI) of the mice was recorded, changes in the organizational structure of the colon were observed and the spleen index (SI) was measured. In addition, levels of interleukin (IL)-6, IL-10, IL-17 and transforming growth factor (TGF)-β1 in the plasma and hypoxia-inducible factor (HIF)-1α and signal transducer and activator of transcription (STAT) 3 protein expression in colon tissues were evaluated. Compared with the MD group, the mice in the two EGCG treatment groups exhibited decreased DAIs and SIs and an attenuation in the colonic tissue erosion. EGCG could reduce the release of IL-6 and IL-17 and regulate the mouse splenic regulatory T-cell (Treg)/T helper 17 cell (Th17) ratio, while increasing the plasma levels of IL-10 and TGF-β1 and decreasing the HIF-1α and STAT3 protein expression in the colon. The experiments confirmed that EGCG treated mice with experimental colitis by inhibiting the release of IL-6 and regulating the body Treg/Th17 balance. PMID:26668622

  9. Lymph node trafficking of regulatory T cells is prerequisite for immune suppression.

    PubMed

    Huang, Miao-Tzu; Lin, Been-Ren; Liu, Wei-Liang; Lu, Chun-Wei; Chiang, Bor-Luen

    2016-04-01

    Regulatory T cells have a crucial role in health and disease because of their immune regulation function. However, the anatomic sites where regulatory T cells exert optimal immune regulation are open to debate. In our current study with the use of a shear-stress flow assay, we found that regulatory T cells exhibited significantly decreased adhesion to either activated endothelial monolayer or intercellular adhesion molecule 1 or E-selectin-coated surfaces compared with activated effector T cells. The less transmigration capacity of the regulatory T cells prompted our speculation of preferential lymph node localization for the regulatory T cells that endowed these cells with immune regulation function in the most efficient manner. To test this hypothesis, the role of lymph node localization in regulatory T cell-mediated immune suppression was evaluated with a footpad inflammation model. We found that adoptively transferred regulatory T cells inhibited the development of footpad inflammation. In addition, although blockage of CCR7 or CD62L had no effect on the immune suppressive function of the regulatory T cells per se, pretreatment of the regulatory T cells with either CCR7 or CD62L blocking antibodies prevented their recruitment into draining lymph nodes and concomitantly abrogated the immune suppressive effects of adoptively transferred regulatory T cells during footpad inflammation. Our data demonstrate the crucial role of lymph node localization in regulatory T cell-mediated immune suppression and suggest a probable hierarchy in the anatomic sites for optimal immune regulation. Elucidating the relationships between the transmigration characteristics of the regulatory T cells and their immune regulation function will provide insightful information for regulatory T cell-based cell therapy. PMID:26543091

  10. Natural regulatory T cells in autoimmunity

    PubMed Central

    Lourenço, Elaine V.; La Cava, Antonio

    2010-01-01

    The suppressive/immunomodulatory function of CD4+CD25+Foxp+ regulatory T (Treg) cells is crucial for the maintenance of immune homeostasis, which helps to prevent autoimmunity and reduce the inflammation induced by pathogens and environmental insults. This review summarizes the current knowledge on the types and mechanisms of action of Treg cells and their role in the immune tolerance to self antigens, with a particular focus on naturally occurring Treg cells. PMID:21091291

  11. Regulatory T cells require TCR signaling for their suppressive function

    PubMed Central

    Schmidt, Amanda M.; Lu, Wen; Sindhava, Vishal J.; Huang, Yanping; Burkhardt, Janis K.; Yang, Enjun; Riese, Matthew J.; Maltzman, Jonathan S.; Jordan, Martha S.; Kambayashi, Taku

    2015-01-01

    Regulatory T cells (Tregs) are a subset of CD4+ T cells that maintain immune tolerance in part by their ability to inhibit the proliferation of conventional CD4+ T cells (Tconvs). The role of the T cell receptor (TCR) and the downstream signaling pathways required for this suppressive function of Tregs are not fully understood. To yield insight into how TCR-mediated signals influence Treg suppressive function, we assessed the ability of Tregs with altered TCR-mediated signaling capacity to inhibit Tconv proliferation. Mature Tregs deficient in SLP-76, an adaptor protein that nucleates the proximal signaling complex downstream of the TCR, were unable to inhibit Tconv proliferation, suggesting that TCR signaling is required for Treg suppressive function. Moreover, Tregs with defective PLCγ activation due to a Y145F mutation of SLP-76 were also defective in their suppressive function. Conversely, enhancement of diacylglycerol-mediated signaling downstream of PLCγ by genetic ablation of a negative regulator of diacylglycerol kinase ζ increased the suppressive ability of Tregs. Since SLP-76 is also important for integrin activation and signaling, we tested the role of integrin activation in Treg-mediated suppression. Tregs lacking the adaptor proteins ADAP or Crk/CrkL, which are required for TCR-mediated integrin activation, inhibited Tconv proliferation to a similar extent as wildtype Tregs. Together, these data suggest that TCR-mediated PLCγ activation but not integrin activation is required for Tregs to inhibit Tconv proliferation. PMID:25821220

  12. [Systemic lupus erythematosus and regulatory T cells].

    PubMed

    Miyara, M; Amoura, Z; Piette, J-C; Gorochov, G

    2008-09-01

    A global depletion of FoxP3+ CD25(bright) CD4+ regulatory T cell is observed during lupus flares. This phenomenon is not the consequence of the relocalization of Tregs in diseased organs but could be related to their specific sensitivity to Fas mediated apoptosis. Several therapeutic perspectives can be drawn taking into account these pathophysiological insights. PMID:18538896

  13. Promoting transplantation tolerance; adoptive regulatory T cell therapy

    PubMed Central

    Safinia, N; Leech, J; Hernandez-Fuentes, M; Lechler, R; Lombardi, G

    2013-01-01

    Transplantation is a successful treatment for end-stage organ failure. Despite improvements in short-term outcome, long-term survival remains suboptimal because of the morbidity and mortality associated with long-term use of immunosuppression. There is, therefore, a pressing need to devise protocols that induce tolerance in order to minimize or completely withdraw immunosuppression in transplant recipients. In this review we will discuss how regulatory T cells (Tregs) came to be recognized as an attractive way to promote transplantation tolerance. We will summarize the preclinical data, supporting the importance of these cells in the induction and maintenance of immune tolerance and that provide the rationale for the isolation and expansion of these cells for cellular therapy. We will also describe the data from the first clinical trials, using Tregs to inhibit graft-versus-host disease (GVHD) after haematopoietic stem cell transplantation and will address both the challenges and opportunities in human Treg cell therapy. PMID:23574313

  14. Regulatory T cells in allergic diseases.

    PubMed

    Noval Rivas, Magali; Chatila, Talal A

    2016-09-01

    The pathogenesis of allergic diseases entails an ineffective tolerogenic immune response to allergens. Regulatory T (Treg) cells play a key role in sustaining immune tolerance to allergens, yet mechanisms by which Treg cells fail to maintain tolerance in patients with allergic diseases are not well understood. We review current concepts and established mechanisms regarding how Treg cells regulate different components of allergen-triggered immune responses to promote and maintain tolerance. We will also discuss more recent advances that emphasize the "dual" functionality of Treg cells in patients with allergic diseases: how Treg cells are essential in promoting tolerance to allergens but also how a proallergic inflammatory environment can skew Treg cells toward a pathogenic phenotype that aggravates and perpetuates disease. These advances highlight opportunities for novel therapeutic strategies that aim to re-establish tolerance in patients with chronic allergic diseases by promoting Treg cell stability and function. PMID:27596705

  15. Targeting regulatory T cells in tumors.

    PubMed

    Liu, Chang; Workman, Creg J; Vignali, Dario A A

    2016-07-01

    Regulatory T (Treg ) cells play a crucial role in maintaining peripheral tolerance and preventing autoimmunity. However, they also represent a major barrier to effective antitumor immunity and immunotherapy. Consequently, there has been considerable interest in developing approaches that can selectively or preferentially target Treg cells in tumors, while not impacting their capacity to maintain peripheral immune homeostasis. In this review, we describe our current understanding of the mechanisms underlying the recruitment, expansion, and suppressive activity of tumor-associated Treg cells, and discuss the approaches used and the challenges encountered in the immunotherapeutic targeting of Treg cells. In addition, we summarize the primary clinical targets and some emerging data on exciting new potential Treg cell-restricted targets. We propose that discovering and understanding mechanisms that are preferentially used by Treg cells within the tumor microenvironment will lead to strategies that selectively target Treg cell-mediated suppression of antitumor immunity while maintaining peripheral immune tolerance. PMID:26787424

  16. Hurdles in therapy with regulatory T cells.

    PubMed

    Trzonkowski, Piotr; Bacchetta, Rosa; Battaglia, Manuela; Berglund, David; Bohnenkamp, Hermann Richard; ten Brinke, Anja; Bushell, Andrew; Cools, Nathalie; Geissler, Edward K; Gregori, Silvia; Marieke van Ham, S; Hilkens, Catharien; Hutchinson, James A; Lombardi, Giovanna; Madrigal, J Alejandro; Marek-Trzonkowska, Natalia; Martinez-Caceres, Eva M; Roncarolo, Maria Grazia; Sanchez-Ramon, Silvia; Saudemont, Aurore; Sawitzki, Birgit

    2015-09-01

    Improper activation of the immune system contributes to a variety of clinical conditions, including autoimmune and allergic diseases as well as solid organ and bone marrow transplantation. One approach to counteract this activation is through adoptive therapy with regulatory T cells (Tregs). Efforts to manufacture these cells have led to good maunfacturing practice-compliant protocols, and Treg products are entering early clinical trials. Here, we report the stance of the European Union Cooperation in Science and Technology Action BM1305, "Action to Focus and Accelerate Cell-based Tolerance-inducing Therapies-A FACTT," which identifies hurdles hindering Treg clinical applications in Europe and provides possible solutions. PMID:26355029

  17. Regulatory B cells control T-cell autoimmunity through IL-21-dependent cognate interactions.

    PubMed

    Yoshizaki, Ayumi; Miyagaki, Tomomitsu; DiLillo, David J; Matsushita, Takashi; Horikawa, Mayuka; Kountikov, Evgueni I; Spolski, Rosanne; Poe, Jonathan C; Leonard, Warren J; Tedder, Thomas F

    2012-11-01

    B cells regulate immune responses by producing antigen-specific antibodies. However, specific B-cell subsets can also negatively regulate T-cell immune responses, and have been termed regulatory B cells. Human and mouse regulatory B cells (B10 cells) with the ability to express the inhibitory cytokine interleukin-10 (IL-10) have been identified. Although rare, B10 cells are potent negative regulators of antigen-specific inflammation and T-cell-dependent autoimmune diseases in mice. How B10-cell IL-10 production and regulation of antigen-specific immune responses are controlled in vivo without inducing systemic immunosuppression is unknown. Using a mouse model for multiple sclerosis, here we show that B10-cell maturation into functional IL-10-secreting effector cells that inhibit in vivo autoimmune disease requires IL-21 and CD40-dependent cognate interactions with T cells. Moreover, the ex vivo provision of CD40 and IL-21 receptor signals can drive B10-cell development and expansion by four-million-fold, and generate B10 effector cells producing IL-10 that markedly inhibit disease symptoms when transferred into mice with established autoimmune disease. The ex vivo expansion and reinfusion of autologous B10 cells may provide a novel and effective in vivo treatment for severe autoimmune diseases that are resistant to current therapies. PMID:23064231

  18. The Ebola Virus VP35 Protein Inhibits Activation of Interferon Regulatory Factor 3

    PubMed Central

    Basler, Christopher F.; Mikulasova, Andrea; Martinez-Sobrido, Luis; Paragas, Jason; Mühlberger, Elke; Bray, Mike; Klenk, Hans-Dieter; Palese, Peter; García-Sastre, Adolfo

    2003-01-01

    The Ebola virus VP35 protein was previously found to act as an interferon (IFN) antagonist which could complement growth of influenza delNS1 virus, a mutant influenza virus lacking the influenza virus IFN antagonist protein, NS1. The Ebola virus VP35 could also prevent the virus- or double-stranded RNA-mediated transcriptional activation of both the beta IFN (IFN-β) promoter and the IFN-stimulated ISG54 promoter (C. Basler et al., Proc. Natl. Acad. Sci. USA 97:12289-12294, 2000). We now show that VP35 inhibits virus infection-induced transcriptional activation of IFN regulatory factor 3 (IRF-3)-responsive mammalian promoters and that VP35 does not block signaling from the IFN-α/β receptor. The ability of VP35 to inhibit this virus-induced transcription correlates with its ability to block activation of IRF-3, a cellular transcription factor of central importance in initiating the host cell IFN response. We demonstrate that VP35 blocks the Sendai virus-induced activation of two promoters which can be directly activated by IRF-3, namely, the ISG54 promoter and the ISG56 promoter. Further, expression of VP35 prevents the IRF-3-dependent activation of the IFN-α4 promoter in response to viral infection. The inhibition of IRF-3 appears to occur through an inhibition of IRF-3 phosphorylation. VP35 blocks virus-induced IRF-3 phosphorylation and subsequent IRF-3 dimerization and nuclear translocation. Consistent with these observations, Ebola virus infection of Vero cells activated neither transcription from the ISG54 promoter nor nuclear accumulation of IRF-3. These data suggest that in Ebola virus-infected cells, VP35 inhibits the induction of antiviral genes, including the IFN-β gene, by blocking IRF-3 activation. PMID:12829834

  19. CD4+CD25bright T cells in human intestinal lamina propria as regulatory cells.

    PubMed

    Makita, Shin; Kanai, Takanori; Oshima, Shigeru; Uraushihara, Koji; Totsuka, Teruji; Sawada, Taisuke; Nakamura, Tetsuya; Koganei, Kazutaka; Fukushima, Tsuneo; Watanabe, Mamoru

    2004-09-01

    It is well known that immune responses in the intestine remain in a state of controlled inflammation, suggesting that not only active suppression by regulatory T cells plays an important role in the normal intestinal homeostasis, but also its dysregulation leads to the development of inflammatory bowel disease. In this study, we demonstrate that the CD4(+)CD25(bright) T cells reside in the human intestinal lamina propria (LP) and functionally retain regulatory activities. All human LP CD4(+) T cells regardless of CD25 expression constitutively expressed CTLA-4, glucocorticoid-induced TNFR family-related protein, and Foxp3 and proliferate poorly. Although LP CD4(+)CD25(-) T cells showed an activated and anergic/memory phenotype, they did not retain regulatory activity. In LP CD4(+)CD25(+) T cells, however, cells expressing CD25 at high levels (CD4(+)CD25(bright)) suppressed the proliferation and various cytokine productions of CD4(+)CD25(-) T cells. LP CD4(+)CD25(bright) T cells by themselves produced fewer amounts of IL-2, IFN-gamma, and IL-10. Interestingly, LP CD4(+)CD25(bright) T cells with regulatory T activity were significantly increased in patients with active inflammatory bowel disease. These results suggest that CD4(+)CD25(bright) T cells found in the normal and inflamed intestinal mucosa selectively inhibit the host immune response and therefore may contribute to the intestinal immune homeostasis. PMID:15322172

  20. Regulatory T cells in allergy and asthma.

    PubMed

    Larché, Mark

    2007-09-01

    Allergic diseases including asthma have risen considerably in prevalence in the last 50 years. A concomitant rise in autoimmune disease suggests a defect in immunoregulation, rather than a reduction in T-helper type 1 immunity. Immune responses to innocuous environmental antigens in health are characterized by dominant regulation through the production of interleukin-10 and transforming growth factor-beta. Recent studies suggest that diverse populations of regulatory T cells (Treg) play an important role in regulating T-helper type 2 (Th2) responses to allergens, maintaining functional tolerance. Regulatory responses appear to be compromised in allergic individuals but may be reconstituted to some extent with specific allergen immunotherapy. In experimental models, Treg can suppress Th2 responses to allergen, airway eosinophilia, mucous hypersecretion, and airway hyperresponsiveness. Further studies are required to precisely define the mechanisms of development and action of these cells, and to identify and evaluate novel targets for the treatment of allergic diseases. PMID:17873195

  1. Human papillomavirus 16 E6 oncoprotein binds to interferon regulatory factor-3 and inhibits its transcriptional activity

    PubMed Central

    Ronco, Lucienne V.; Karpova, Alla Y.; Vidal, Marc; Howley, Peter M.

    1998-01-01

    Interferon regulatory factor-3 (IRF-3) was found to specifically interact with HPV16 E6 in a yeast two-hybrid screen. IRF-3 is activated by the presence of double-stranded RNA or by virus infection to form a stable complex with other transcriptional regulators that bind to the regulatory elements of the IFNβ promoter. We show that IRF-3 is a potent transcriptional activator and demonstrate that HPV16 E6 can inhibit its transactivation function. The expression of HPV16 E6 in primary human keratinocytes inhibits the induction of IFNβ mRNA following Sendai virus infection. The binding of HPV16 E6 to IRF-3 does not result in its ubiquitination or degradation. We propose that the interaction of E6 with IRF-3 and the inhibition of IRF-3’s transcriptional activity may provide the virus a means to circumvent the normal antiviral response of an HPV16-infected cell. PMID:9649509

  2. T regulatory cells in childhood asthma.

    PubMed

    Strickland, Deborah H; Holt, Patrick G

    2011-09-01

    Asthma is a chronic disease of the airways, most commonly driven by immuno-inflammatory responses to ubiquitous airborne antigens. Epidemiological studies have shown that disease is initiated early in life when the immune and respiratory systems are functionally immature and less able to maintain homeostasis in the face of continuous antigen challenge. Here, we examine the cellular and molecular mechanisms that underlie initial aeroallergen sensitization and the ensuing regulation of secondary responses to inhaled allergens in the airway mucosa. In particular, we focus on how T-regulatory (Treg) cells influence early asthma initiation and the potential of Treg cells as therapeutic targets for drug development in asthma. PMID:21798806

  3. Tumor-educated CD11bhighIalow regulatory dendritic cells suppress T cell response through arginase I.

    PubMed

    Liu, Qiuyan; Zhang, Chaoxiong; Sun, Anna; Zheng, Yuanyuan; Wang, Li; Cao, Xuetao

    2009-05-15

    Tumors can induce generation and accumulation of the immunosuppressive cells such as regulatory T cells in the tumor microenvironment, contributing to tumor escape from immunological attack. Although dendritic cell (DC)-based cancer vaccine can initiate antitumor immune response, regulatory DC subsets involved in the tolerance induction attracted much attention recently. Our previous studies demonstrate that the stromal microenvironment of the spleen, lung, and liver can program generation of CD11c(low)CD11b(high)Ia(low) DCs with regulatory function (CD11b(high)Ia(low) regulatory DCs). However, whether and how the tumor microenvironment can program generation of CD11b(high)Ia(low) regulatory DCs remain to be investigated. In this study, we used the freshly isolated tumor cells to mimic tumor microenvironment to coculture DCs and found that the freshly isolated tumor cells could drive DCs to differentiate into regulatory DCs with a CD11c(low)CD11b(high)Ia(low) phenotype and high expression of IL-10, NO, vascular endothelial growth factor, and arginase I. Tumor-educated CD11b(high)Ia(low) regulatory DCs inhibited CD4(+) T cell proliferation both in vitro and in vivo. 3LL lung cancer-derived TGF-beta and PGE(2) were responsible for the generation of regulatory DCs. PGE(2) was the main inducer of arginase I in regulatory DCs. Arginase I played a major role in the suppression of T cell response by regulatory DCs induced by 3LL lung cancer. A natural counterpart of CD11b(high)Ia(low) DCs was identified in tumor tissue, and CD11b(high)Ia(low) DCs sorted from 3LL lung cancer tissue expressed arginase I and inhibited T cell response. Therefore, tumors can educate DCs to differentiate into a regulatory DC subset, which contributes to constitution of the immunosuppressive tumor microenvironment and promotes tumor immune escape. PMID:19414774

  4. Estrogen induces multiple regulatory B cell subtypes and promotes M2 microglia and neuroprotection during experimental autoimmune encephalomyelitis.

    PubMed

    Benedek, Gil; Zhang, Jun; Bodhankar, Sheetal; Nguyen, Ha; Kent, Gail; Jordan, Kelley; Manning, Dustin; Vandenbark, Arthur A; Offner, Halina

    2016-04-15

    Sex hormones promote immunoregulatory effects on multiple sclerosis. The current study evaluated estrogen effects on regulatory B cells and resident CNS microglia during experimental autoimmune encephalomyelitis (EAE). Herein, we demonstrate an estrogen-dependent induction of multiple regulatory B cell markers indicative of IL-10 dependent as well as IFN-γ dependent pathways. Moreover, although estrogen pretreatment of EAE mice inhibited the infiltration of pro-inflammatory cells into the CNS, it enhanced the frequency of regulatory B cells and M2 microglia. Our study suggests that estrogen has a broad effect on the development of regulatory B cells during EAE, which in turn could promote neuroprotection. PMID:27049561

  5. JNK Inhibition Inhibits Lateral Line Neuromast Hair Cell Development

    PubMed Central

    Cai, Chengfu; Lin, Jinchao; Sun, Shaoyang; He, Yingzi

    2016-01-01

    JNK signaling is known to play a role in regulating cell behaviors such as cell cycle progression, cell proliferation, and apoptosis, and recent studies have suggested important roles for JNK signaling in embryonic development. However, the precise function of JNK signaling in hair cell development remains poorly studied. In this study, we used the small molecule JNK inhibitor SP600125 to examine the effect of JNK signaling abrogation on the development of hair cells in the zebrafish lateral line neuromast. Our results showed that SP600125 reduced the numbers of both hair cells and supporting cells in neuromasts during larval development in a dose-dependent manner. Additionally, JNK inhibition strongly inhibited the proliferation of neuromast cells, which likely explains the decrease in the number of differentiated hair cells in inhibitor-treated larvae. Furthermore, western blot and in situ analysis showed that JNK inhibition induced cell cycle arrest through induction of p21 expression. We also showed that SP600125 induced cell death in developing neuromasts as measured by cleaved caspase-3 immunohistochemistry, and this was accompanied with an induction of p53 gene expression. Together these results indicate that JNK might be an important regulator in the development of hair cells in the lateral line in zebrafish by controlling both cell cycle progression and apoptosis. PMID:26903805

  6. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression.

    PubMed

    Wei, Zhiquan; Yan, Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-08-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interferon regulatory factor 5 (IRF5) has been identified as a key regulatory factor for macrophage classical activation. The present study used the THP‑1 human monocyte cell line to investigate whether mangiferin inhibits macrophage classical activation via suppressing IRF5 expression in vitro. THP‑1 cells were differentiated to macrophages by phorbol 12‑myristate 13‑acetate. Macrophages were polarized to M1 macrophages following stimulation with lipopolysaccharide (LPS)/interferon‑γ (IFN‑γ). Flow cytometric analysis was conducted to detect the M1 macrophages. Reverse transcription‑quantitative polymerase chain reaction was used to investigate cellular IRF5 gene expression. Levels of proinflammatory cytokines and IRF5 were assessed following cell culture and cellular homogenization using enzyme‑linked immunosorbent assay. IRF5 protein and nuclei co‑localization was performed in macrophages with laser scanning confocal microscope immunofluorescence analysis. The results of the present study demonstrated that mangiferin significantly inhibits LPS/IFN‑γ stimulation‑induced classical activation of macrophages in vitro and markedly decreases proinflammatory cytokine release. In addition, cellular IRF5 expression was markedly downregulated. These results suggest that the inhibitory effect of mangiferin on classical activation of macrophages may be exerted via downregulation of cellular IRF5 expression levels. PMID:27277156

  7. Mangiferin inhibits macrophage classical activation via downregulating interferon regulatory factor 5 expression

    PubMed Central

    Wei, Zhiquan; Yan, Li; Chen, Yixin; Bao, Chuanhong; Deng, Jing; Deng, Jiagang

    2016-01-01

    Mangiferin is a natural polyphenol and the predominant effective component of Mangifera indica Linn. leaves. For hundreds of years, Mangifera indica Linn. leaf has been used as an ingredient in numerous traditional Chinese medicine preparations for the treatment of bronchitis. However, the pharmacological mechanism of mangiferin in the treatment of bronchitis remains to be elucidated. Macrophage classical activation is important role in the process of bronchial airway inflammation, and interferon regulatory factor 5 (IRF5) has been identified as a key regulatory factor for macrophage classical activation. The present study used the THP-1 human monocyte cell line to investigate whether mangiferin inhibits macrophage classical activation via suppressing IRF5 expression in vitro. THP-1 cells were differentiated to macrophages by phorbol 12-myristate 13-acetate. Macrophages were polarized to M1 macrophages following stimulation with lipopolysaccharide (LPS)/interferon-γ (IFN-γ). Flow cytometric analysis was conducted to detect the M1 macrophages. Reverse transcription-quantitative polymerase chain reaction was used to investigate cellular IRF5 gene expression. Levels of proinflammatory cytokines and IRF5 were assessed following cell culture and cellular homogenization using enzyme-linked immunosorbent assay. IRF5 protein and nuclei co-localization was performed in macrophages with laser scanning confocal microscope immunofluorescence analysis. The results of the present study demonstrated that mangiferin significantly inhibits LPS/IFN-γ stimulation-induced classical activation of macrophages in vitro and markedly decreases proinflammatory cytokine release. In addition, cellular IRF5 expression was markedly downregulated. These results suggest that the inhibitory effect of mangiferin on classical activation of macrophages may be exerted via downregulation of cellular IRF5 expression levels. PMID:27277156

  8. Regulatory T cells: regulators of life.

    PubMed

    Schumacher, Anne; Zenclussen, Ana Claudia

    2014-08-01

    Pregnancy still represents one of the most fascinating paradoxical phenomena in science. Immediately after conception, the maternal immune system is challenged by the presence of foreign paternal antigens in the semen. This triggers mechanisms of recognition and tolerance that all together allow the embryo to implant and later the fetus to develop. Tolerance mechanisms to maintain pregnancy are of special interest as they defy the classical immunology rules. Several cell types, soluble factors, and immune regulatory molecules have been proposed to contribute to fetal tolerance. Within these, regulatory T cells (Treg) are one of the most studied immune cell populations lately. They are reportedly involved in fetal acceptance. Here, we summarize several aspects of Treg biology in normal and pathologic pregnancies focusing on Treg frequencies, subtypes, antigen specificity, and activity as well as on factors influencing Treg generation, recruitment, and function. This review also highlights the contribution of fetal Treg in tolerance induction and addresses the role of Treg in autoimmune diseases and infections during gestation. Finally, the potential of Treg as a predictive marker for the success of assisted reproductive techniques and for therapeutic interventions is discussed. PMID:24661545

  9. Interleukin 10 and dendritic cells are the main suppression mediators of regulatory T cells in human neurocysticercosis.

    PubMed

    Arce-Sillas, A; Álvarez-Luquín, D D; Cárdenas, G; Casanova-Hernández, D; Fragoso, G; Hernández, M; Proaño Narváez, J V; García-Vázquez, F; Fleury, A; Sciutto, E; Adalid-Peralta, L

    2016-02-01

    Neurocysticercosis is caused by the establishment of Taenia solium cysticerci in the central nervous system. It is considered that, during co-evolution, the parasite developed strategies to modulate the host's immune response. The action mechanisms of regulatory T cells in controlling the immune response in neurocysticercosis are studied in this work. Higher blood levels of regulatory T cells with CD4(+) CD45RO(+) forkhead box protein 3 (FoxP3)(high) and CD4(+) CD25(high) FoxP3(+) CD95(high) phenotype and of non-regulatory CD4(+) CD45RO(+) FoxP3(med) T cells were found in neurocysticercosis patients with respect to controls. Interestingly, regulatory T cells express higher levels of cytotoxic T lymphocyte antigen 4 (CTLA-4), lymphocyte-activation gene 3 (LAG-3), programmed death 1 (PD-1) and glucocorticoid-induced tumour necrosis factor receptor (GITR), suggesting a cell-to-cell contact mechanism with dendritic cells. Furthermore, higher IL-10 and regulatory T cell type 1 (Tr1) levels were found in neurocysticercosis patients' peripheral blood, suggesting that the action mechanism of regulatory T cells involves the release of immunomodulatory cytokines. No evidence was found of the regulatory T cell role in inhibiting the proliferative response. Suppressive regulatory T cells from neurocysticercosis patients correlated negatively with late activated lymphocytes (CD4(+) CD38(+) ). Our results suggest that, during neurocysticercosis, regulatory T cells could control the immune response, probably by a cell-to-cell contact with dendritic cells and interleukin (IL)-10 release by Tr1, to create an immunomodulatory environment that may favour the development of T. solium cysticerci and their permanence in the central nervous system. PMID:26391104

  10. T regulatory cells and their counterparts: masters of immune regulation.

    PubMed

    Ozdemir, C; Akdis, M; Akdis, C A

    2009-05-01

    The interaction of environmental and genetic factors with the immune system can lead to the development of allergic diseases. The essential step in this progress is the generation of allergen-specific CD4(+) T-helper (Th) type 2 cells that mediate several effector functions. The influence of Th2 cytokines leads to the production of allergen-specific IgE antibodies by B cells, development and recruitment of eosinophils, mucus production and bronchial hyperreactivity, as well as tissue homing of other Th2 cells and eosinophils. Meanwhile, Th1 cells may contribute to chronicity and the effector phases. T cells termed T regulatory (Treg) cells, which have immunosuppressive functions and cytokine profiles distinct from that of either Th1 or Th2 cells, have been intensely investigated during the last 13 years. Treg cell response is characterized by an abolished allergen-specific T cell proliferation and the suppressed secretion of Th1 and Th2-type cytokines. Treg cells are able to inhibit the development of allergen-specific Th2 and Th1 cell responses and therefore play an important role in a healthy immune response to allergens. In addition, Treg cells potently suppress IgE production and directly or indirectly suppress the activity of effector cells of allergic inflammation, such as eosinophils, basophils and mast cells. Currently, Treg cells represent an exciting area of research, where understanding the mechanisms of peripheral tolerance to allergens may soon lead to more rational and safer approaches for the prevention and cure of allergic diseases. PMID:19422105

  11. Regulatory Circuits Controlling Vascular Cell Calcification

    PubMed Central

    Sallam, Tamer; Cheng, Henry; Demer, Linda L.; Tintut, Yin

    2013-01-01

    Vascular calcification is a common feature of chronic kidney disease, cardiovascular disease, and aging. Such abnormal calcium deposition occurs in medial and/or intimal layers of blood vessels as well as in cardiac valves. Once considered a passive and inconsequential finding, the presence of calcium deposits in the vasculature is widely accepted as a predictor of increased morbidity and mortality. Recognition of the importance of vascular calcification in health is driving research into mechanisms that govern its development, progression, and regression. Diverse, but highly interconnected factors, have been implicated, including disturbances in lipid metabolism, oxidative stress, inflammatory cytokines, and mineral and hormonal balances, which can lead to formation of osteoblast-like cells in the artery wall. A tight balance of procalcific and anticalcific regulators dictates the extent of disease. In this review, we focus on the main regulatory circuits modulating vascular cell calcification. PMID:23269436

  12. Regulatory T cells are baby's best friends.

    PubMed

    Teles, Ana; Zenclussen, Ana Claudia; Schumacher, Anne

    2013-04-01

    Regulatory T cells (Treg) are one of the most and best studied immune cell population during human and murine pregnancy, and there is a general consent about their expansion during pregnancy. However, the identification of new and more reliable Treg markers during the last years resulted in some controversies about the kinetics of various Treg subsets at different pregnancy stages. No doubt exists regarding the importance of Treg for a normal pregnancy as pregnancy complications like spontaneous abortion and preeclampsia could be associated with a reduced Treg number and activity. In future, more attention should be paid to bring established data from the bench to the bedside to force the development of adequate therapies for treatment of pregnancy complications. In this article, we summarize previous and recent data on several aspects of Treg biology during human and murine pregnancy. PMID:23289369

  13. Impaired regulatory B cells in myasthenia gravis.

    PubMed

    Sheng, Jian Rong; Rezania, Kourosh; Soliven, Betty

    2016-08-15

    Regulatory B cells (Bregs) attenuate the severity of experimental autoimmune myasthenia gravis (EAMG) in an interleukin-10 (IL-10)-dependent manner. The goal of this study was to investigate the role of human Bregs in MG focusing on CD19(+)CD1d(hi) CD5(+) and CD19(+)CD24(hi)CD38(hi) subsets. We found that MG patients exhibited a decrease in the frequency of both Breg subsets and IL-10 producing B cells within each subset, which correlated with disease severity. In addition, there was impaired suppression of Th1 polarization in MG. These findings, taken together with EAMG data, indicate that Bregs play an important role in regulating the severity of MG. PMID:27397074

  14. Radiation Enhances Regulatory T Cell Representation

    SciTech Connect

    Kachikwu, Evelyn L.; Iwamoto, Keisuke S.; Liao, Yu-Pei; DeMarco, John J.; Agazaryan, Nzhde; Economou, James S.; McBride, William H.; Schaue, Doerthe

    2011-11-15

    Purpose: Immunotherapy could be a useful adjunct to standard cytotoxic therapies such as radiation in patients with micrometastatic disease, although successful integration of immunotherapy into treatment protocols will require further understanding of how standard therapies affect the generation of antitumor immune responses. This study was undertaken to evaluate the impact of radiation therapy (RT) on immunosuppressive T regulatory (Treg) cells. Methods and Materials: Treg cells were identified as a CD4{sup +}CD25{sup hi}Foxp3{sup +} lymphocyte subset, and their fate was followed in a murine TRAMP C1 model of prostate cancer in mice with and without RT. Results: CD4{sup +}CD25{sup hi}Foxp3{sup +} Treg cells increased in immune organs after local leg or whole-body radiation. A large part, but not all, of this increase after leg-only irradiation could be ascribed to radiation scatter and Treg cells being intrinsically more radiation resistant than other lymphocyte subpopulations, resulting in their selection. Their functional activity on a per-cell basis was not affected by radiation exposure. Similar findings were made with mice receiving local RT to murine prostate tumors growing in the leg. The importance of the Treg cell population in the response to RT was shown by systemic elimination of Treg cells, which greatly enhanced radiation-induced tumor regression. Conclusions: We conclude that Treg cells are more resistant to radiation than other lymphocytes, resulting in their preferential increase. Treg cells may form an important homeostatic mechanism for tissues injured by radiation, and in a tumor context, they may assist in immune evasion during therapy. Targeting this population may allow enhancement of radiotherapeutic benefit through immune modulation.

  15. Regulatory T Cells in Post-stroke Immune Homeostasis.

    PubMed

    Liesz, Arthur; Kleinschnitz, Christoph

    2016-08-01

    The secondary neuroinflammatory response has come into focus of experimental stroke research. Immunological mechanisms after acute stroke are being investigated in the hope to identify novel and druggable pathways that contribute to secondary infarct growth after stroke. Among a variety of neuroimmunological events after acute brain ischemia, including microglial activation, brain leukocyte invasion, and secretion of pro-inflammatory factors, lymphocytes have been identified as the key leukocyte subpopulation driving the neuroinflammatory response and contributing to stroke outcome. Several studies have shown that pro-inflammatory lymphocyte subpopulations worsen stroke outcome and that inhibiting their invasion to the injured brain is neuroprotective. In contrast to the effector functions of pro-inflammatory lymphocytes, regulatory T cells (Treg) are critically involved in maintaining immune homeostasis and have been characterized as disease-limiting protective cells in several inflammatory conditions, particularly in primary inflammatory diseases of the central nervous system (CNS). However, due to the complex function of regulatory cells in immune homeostasis and disease, divergent findings have been described for the role of Treg in stroke models. Emerging evidence suggests that this discrepancy arises from potentially differing functions of Treg depending on the predominant site of action within the neurovascular unit and the surrounding inflammatory milieu. This article will provide a comprehensive review of current findings on Treg in brain ischemia models and discuss potential reasons for the observed discrepancies. PMID:27030356

  16. REGULATORY AND RESEARCH ISSUES RELATED TO CHOLINESTERASE INHIBITION

    EPA Science Inventory

    Assessing the neurotoxic potential of organophosphate and carbamate pesticides should be greatly facilitated by the knowledge that the mechanisms of action of these insecticides is presumed to be the inhibition of cholinesterase, the enzyme which controls the levels of the neurot...

  17. Upholding the T cell immune-regulatory function of CD31 inhibits the formation of T/B immunological synapses in vitro and attenuates the development of experimental autoimmune arthritis in vivo.

    PubMed

    Clement, Marc; Fornasa, Giulia; Loyau, Stéphane; Morvan, Marion; Andreata, Francesco; Guedj, Kevin; Khallou-Laschet, Jamila; Larghi, Paola; Le Roux, Delphine; Bismuth, Georges; Chiocchia, Gilles; Hivroz, Claire; Newman, Debra K; Nicoletti, Antonino; Caligiuri, Giuseppina

    2015-01-01

    CD31, a trans-homophilic inhibitory receptor expressed on both T- and B-lymphocytes, drives the mutual detachment of interacting leukocytes. Intriguingly, T cell CD31 molecules relocate to the immunological synapse (IS), where the T and B cells establish a stable interaction. Here, we show that intact CD31 molecules, which are able to drive an inhibitory signal, are concentrated at the periphery of the IS but are excluded from the center of the IS. At this site, were the cells establish the closest contact, the CD31 molecules are cleaved, and most of the extracellular portion of the protein, including the trans-homophilic binding sites, is shed from the cell surface. T cells lacking CD31 trans-homophilic binding sites easily establish stable interactions with B cells; at the opposite, CD31 signaling agonists inhibit T/B IS formation as well as the ensuing helper T cell activation and function. Confocal microscopy and flow cytometry analysis of experimental T/B IS shows that the T cell inhibitory effects of CD31 agonists depend on SHP-2 signaling, which reduces the phosphorylation of ZAP70. The analysis of synovial tissue biopsies from patients affected by rheumatoid arthritis showed that T cell CD31 molecules are excluded from the center of the T/B cell synapses in vivo. Interestingly, the administration of CD31 agonists in vivo significantly attenuated the development of the clinical signs of collagen-induced arthritis in DBA1/J mice. Altogether, our data indicate that the T cell co-inhibitory receptor CD31 prevents the formation of functional T/B immunological synapses and that therapeutic strategies aimed at sustaining CD31 signaling will attenuate the development of autoimmune responses in vivo. PMID:25277651

  18. Nesfatin-1 inhibits ovarian epithelial carcinoma cell proliferation in vitro

    SciTech Connect

    Xu, Yang; Pang, Xiaoyan; Dong, Mei; Wen, Fang Zhang, Yi

    2013-11-01

    Highlights: •Nesfatin-1 inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest. •Nesfatin-1 enhances HO-8910 cell apoptosis. •Nesfatin-1 inhibits HO-8910 cell proliferation via mTOR and RhoA/ROCK signaling pathway. •The first report of nesfatin-1-mediated proliferation in ovarian epithelial carcinoma. -- Abstract: Nesfatin-1, an 82-amino-acid peptide derived from a 396-amino-acid precursor protein nucleobindin 2 (NUCB2), was originally identified in hypothalamic nuclei involved in the regulation of food intake. It was recently reported that nesfatin-1 is a novel depot specific adipokine preferentially produced by subcutaneous tissue, with obesity- and food deprivation-regulated expression. Although a relation between ovarian cancer mortality and obesity has been previously established, a role of nesfatin-1 in ovarian epithelial carcinoma remains unknown. The aim of the present study is to examine the effect of nesfatin-1 on ovary carcinoma cells proliferation. We found that nesfatin-1 inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest, this inhibition could be abolished by nesfatin-1 neutralizing antibody. Nesfatin-1 enhances HO-8910 cell apoptosis, activation of mammalian target of rapamycin (mTOR) and RhoA/ROCK signaling pathway block the effects of nesfatin-1-induced apoptosis, therefore reverses the inhibition of HO-8910 cell proliferation by nesfatin-1. In conclusion, the present study demonstrated that nesfatin-1 can inhibit the proliferation in human ovarian epithelial carcinoma cell line HO-8910 cells through inducing apoptosis via mTOR and RhoA/ROCK signaling pathway. This study provides a novel regulatory signaling pathway of nesfatin-1-regulated ovarian epithelial carcinoma growth and may contribute to ovarian cancer prevention and therapy, especially in obese patients.

  19. Complement-induced regulatory T cells suppress T-cell responses but allow for dendritic-cell maturation

    PubMed Central

    Barchet, Winfried; Price, Jeffrey D.; Cella, Marina; Colonna, Marco; MacMillan, Sandra K.; Cobb, J. Perren; Thompson, Paul A.; Murphy, Kenneth M.; Atkinson, John P.; Kemper, Claudia

    2006-01-01

    Concurrent activation of the T-cell receptor (TCR) and complement regulator CD46 on human CD4+ T lymphocytes induces Tr1-like regulatory T cells that suppress through IL-10 secretion bystander T-cell proliferation. Here we show that, despite their IL-10 production, CD46-induced T-regulatory T cells (Tregs) do not suppress the activation/maturation of dendritic cells (DCs). DC maturation by complement/CD46-induced Tregs is mediated through simultaneous secretion of GM-CSF and soluble CD40L, factors favoring DC differentiation and reversing inhibitory effects of IL-10. Thus, CD46-induced Tregs produce a distinct cytokine profile that inhibits T-cell responses but leaves DC activation unimpaired. Such “DC-sparing” Tregs could be desirable at host/environment interfaces such as the gastrointestinal tract where their specific cytokine profile provides a mechanism that ensures unresponsiveness to commensal bacteria while maintaining reactivity to invading pathogens. PMID:16239430

  20. Unexpected T cell regulatory activity of anti-histone H1 autoantibody: Its mode of action in regulatory T cell-dependent and -independent manners

    SciTech Connect

    Takaoka, Yuki; Kawamoto, Seiji; Katayama, Akiko; Nakano, Toshiaki; Yamanaka, Yasushi; Takahashi, Miki; Shimada, Yayoi; Chiang, Kuei-Chen; Ohmori, Naoya; Aki, Tsunehiro; Goto, Takeshi; Sato, Shuji; Goto, Shigeru; Chen, Chao-Long; Ono, Kazuhisa

    2013-02-08

    Highlights: ► Anti-histone H1 autoantibody (anti-H1) acts on T cells to inhibit their activation. ► Anti-H1 suppresses T cell activation in Treg cell-dependent and -independent manners. ► Suboptimal dose of anti-H1 enhances suppressor function of Treg cells. ► High dose of anti-H1 directly inhibits T cell receptor signaling. -- Abstract: Induction of anti-nuclear antibodies against DNA or histones is a hallmark of autoimmune disorders, but their actual contribution to disease predisposition remains to be clarified. We have previously reported that autoantibodies against histone H1 work as a critical graft survival factor in a rat model of tolerogeneic liver transplantation. Here we show that an immunosuppressive anti-histone H1 monoclonal antibody (anti-H1 mAb) acts directly on T cells to inhibit their activation in response to T cell receptor (TCR) ligation. Intriguingly, the T cell activation inhibitory activity of anti-H1 mAb under suboptimal dosages required regulatory T (Treg) cells, while high dose stimulation with anti-H1 mAb triggered a Treg cell-independent, direct negative regulation of T cell activation upon TCR cross-linking. In the Treg cell-dependent mode of immunosuppressive action, anti-H1 mAb did not induce the expansion of CD4{sup +}Foxp3{sup +} Treg cells, but rather potentiated their regulatory capacity. These results reveal a previously unappreciated T cell regulatory role of anti-H1 autoantibody, whose overproduction is generally thought to be pathogenic in the autoimmune settings.

  1. The Molecular Mechanisms of Regulatory T Cell Immunosuppression

    PubMed Central

    Pandiyan, Pushpa; Zheng, Lixin; Lenardo, Michael J.

    2011-01-01

    CD4+CD25+Foxp3+ T lymphocytes, known as regulatory T cells or Tregs, have been proposed to be a lineage of professional immune suppressive cells that exclusively counteract the effects of the immunoprotective “helper” and “cytotoxic” lineages of T lymphocytes. Here we discuss new concepts on the mechanisms and functions of Tregs. There are several key points we emphasize: 1. Tregs exert suppressive effects both directly on effector T cells and indirectly through antigen-presenting cells; 2. Regulation can occur through a novel mechanism of cytokine consumption to regulate as opposed to the usual mechanism of cytokine/chemokine production; 3. In cases where CD4+ effector T cells are directly inhibited by Tregs, it is chiefly through a mechanism of lymphokine withdrawal apoptosis leading to polyclonal deletion; and 4. Contrary to the current view, we discuss new evidence that Tregs, similar to other T-cells lineages, can promote protective immune responses in certain infectious contexts (Chen et al., 2011; Pandiyan et al., 2011). Although these points are at variance to varying degrees with the standard model of Treg behavior, we will recount developing findings that support these new concepts. PMID:22566849

  2. Subsets of regulatory T cells and their roles in allergy.

    PubMed

    Zhang, Huiyun; Kong, Hui; Zeng, Xiaoning; Guo, Lianyi; Sun, Xiaoyun; He, Shaoheng

    2014-01-01

    In recent years, it is recognized that acquired immunity is controlled by regulatory T cell (Treg). Since fundamental pathophysiological changes of allergy are mainly caused by hyperresponsiveness of immune system to allergens that acquires after birth, Tregs likely play key roles in the pathogenesis of allergy, particularly during the sensitization phase. However, accumulated information indicate that there are several distinctive subtypes of Tregs in man, and each of them seems to play different role in controlling immune system, which complicates the involvement of Tregs in allergy. The aim of the present study is to attempt to classify subtypes of Tregs and summarize their roles in allergy. Tregs should include natural Tregs (nTreg) including inducible costimulator (ICOS)(+) Tregs, inducible/adaptive Tregs (iTreg), interleukin (IL)-10-producing type 1 Tregs (Tr1 cells), CD8(+) Tregs and IL-17-producing Tregs. These cells share some common features including expression of Foxp3 (except for Tr1 cells), and secretion of inhibitory cytokine IL-10 and/or TGF-β. Furthermore, it is noticeable that Tregs likely contribute to allergic disorders such as dermatitis and airway inflammation, and play a crucial role in the treatment of allergy through their actions on suppression of effector T cells and inhibition of activation of mast cells and basophils. Modulation of functions of Tregs may provide a novel strategy to prevent and treat allergic diseases. PMID:24886492

  3. Subsets of regulatory T cells and their roles in allergy

    PubMed Central

    2014-01-01

    In recent years, it is recognized that acquired immunity is controlled by regulatory T cell (Treg). Since fundamental pathophysiological changes of allergy are mainly caused by hyperresponsiveness of immune system to allergens that acquires after birth, Tregs likely play key roles in the pathogenesis of allergy, particularly during the sensitization phase. However, accumulated information indicate that there are several distinctive subtypes of Tregs in man, and each of them seems to play different role in controlling immune system, which complicates the involvement of Tregs in allergy. The aim of the present study is to attempt to classify subtypes of Tregs and summarize their roles in allergy. Tregs should include natural Tregs (nTreg) including inducible costimulator (ICOS)(+) Tregs, inducible/adaptive Tregs (iTreg), interleukin (IL)-10-producing type 1 Tregs (Tr1 cells), CD8(+) Tregs and IL-17-producing Tregs. These cells share some common features including expression of Foxp3 (except for Tr1 cells), and secretion of inhibitory cytokine IL-10 and/or TGF-β. Furthermore, it is noticeable that Tregs likely contribute to allergic disorders such as dermatitis and airway inflammation, and play a crucial role in the treatment of allergy through their actions on suppression of effector T cells and inhibition of activation of mast cells and basophils. Modulation of functions of Tregs may provide a novel strategy to prevent and treat allergic diseases. PMID:24886492

  4. Regulatory T Cells: Differentiation and Function.

    PubMed

    Plitas, George; Rudensky, Alexander Y

    2016-09-01

    The immune system of vertebrate animals has evolved to mount an effective defense against a diverse set of pathogens while minimizing transient or lasting impairment in tissue function that could result from the inflammation caused by immune responses to infectious agents. In addition, misguided immune responses to "self" and dietary antigens, as well as to commensal microorganisms, can lead to a variety of inflammatory disorders, including autoimmunity, metabolic syndrome, allergies, and cancer. Regulatory T cells expressing the X chromosome-linked transcription factor Foxp3 suppress inflammatory responses in diverse biological settings and serve as a vital mechanism of negative regulation of immune-mediated inflammation. Cancer Immunol Res; 4(9); 721-5. ©2016 AACR. PMID:27590281

  5. Bovine γδ T Cells Are a Major Regulatory T Cell Subset

    PubMed Central

    Hope, Jayne; Taylor, Geraldine; Smith, Adrian L.; Cubillos-Zapata, Carolina; Charleston, Bryan

    2014-01-01

    In humans and mice, γδ T cells represent <5% of the total circulating lymphocytes. In contrast, the γδ T cell compartment in ruminants accounts for 15–60% of the total circulating mononuclear lymphocytes. Despite the existence of CD4+CD25high Foxp3+ T cells in the bovine system, these are neither anergic nor suppressive. We present evidence showing that bovine γδ T cells are the major regulatory T cell subset in peripheral blood. These γδ T cells spontaneously secrete IL-10 and proliferate in response to IL-10, TGF-β, and contact with APCs. IL-10–expressing γδ T cells inhibit Ag-specific and nonspecific proliferation of CD4+ and CD8+ T cells in vitro. APC subsets expressing IL-10 and TFG-β regulate proliferation of γδ T cells producing IL-10. We propose that γδ T cells are a major regulatory T cell population in the bovine system. PMID:24890724

  6. T Cell Signaling Targets for Enhancing Regulatory or Effector Function

    PubMed Central

    Pan, Fan; Fan, Huimin; Liu, Zhongmin; Jiang, Shuiping

    2015-01-01

    To respond to infection, resting or naïve T cells must undergo activation, clonal expansion, and differentiation into specialized functional subsets of effector T cells. However, to prevent excessive or self-destructive immune responses, regulatory T cells (Tregs) are instrumental in suppressing the activation and function of effector cells, including effector T cells. The transcription factor Forkhead box P3 (Foxp3) regulates the expression of genes involved in the development and function of Tregs. Foxp3 interacts with other transcription factors and with epigenetic elements such as histone deacetylases (HDACs) and histone acetyltransferases. Treg suppressive function can be increased by exposure to HDAC inhibitors. The individual contributions of different HDAC family members to Treg function and their respective mechanisms of action, however, remain unclear. A study showed that HDAC6, HDAC9, and Sirtuin-1 had distinct effects on Foxp3 expression and function, suggesting that selectively targeting HDACs individually or in combination may enhance Treg stability and suppressive function. Another study showed that the receptor programmed death 1 (PD-1), a well-known inhibitor of T cell activation, halted cell cycle progression in effector T cells by inhibiting the transcription of the gene encoding the substrate-recognition component (Skp2) of the ubiquitin ligase SCFSkp2. Together, these findings reveal new signaling targets for enhancing Treg or effector T cell function that may be helpful in designing future therapies, either to increase Treg suppressive function in transplantation and autoimmune diseases or to block PD-1 function, thus increasing the magnitude of antiviral or antitumor immune responses of effector T cells. PMID:22855503

  7. Regulatory T cells and antigen-specific tolerance.

    PubMed

    Kretschmer, Karsten; Apostolou, Irina; Verginis, Panos; von Boehmer, Harald

    2008-01-01

    Foxp3-expressing regulatory T cells (Tregs) have an essential function of preventing autoimmune disease in man and mouse. Foxp3 binds to forkhead motifs of about 1,100 genes and the strength of binding increases upon PMA/ionomycin stimulation. In Foxp3-expressing T-cell hybridomas, Foxp3 promoter binding does not lead to activation or suppression of genes which becomes only visible after T-cell activation. These findings are in line with observations by others that Foxp3 exerts important functions through association with Tcell receptor (TCR)-dependent transcription factors in a DNAbinding complex. Tregs can be generated when developing T cells encounter TCR agonist ligands in the thymus. This pro - cess requires costimulatory signals. In contrast, extra thymic conversion of naive T cells into Tregs is inhibited by costimulation. In fact, DC-derived retinoic acid (RA) helps the conversion process by counteracting the negative impact of costimulation. Since AP-1 is produced after costimulation and appears to interfere with Foxp3-NFAT transcription complexes, it is of interest to note that RA interferes with AP-1-dependent transcription. Thus, RA may interfere with the negative impact of costimulation on Treg conversion by interfering with the generation and/or function of AP-1. PMID:18802332

  8. Purification and stability characterization of a cell regulatory sialoglycopeptide inhibitor

    NASA Technical Reports Server (NTRS)

    Moos, P. J.; Fattaey, H. K.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    Previous attempts to physically separate the cell cycle inhibitory and protease activities in preparations of a purified cell regulatory sialoglycopeptide (CeReS) inhibitor were largely unsuccessful. Gradient elution of the inhibitor preparation from a DEAE HPLC column separated the cell growth inhibitor from the protease, and the two activities have been shown to be distinct and non-overlapping. The additional purification increased the specific biological activity of the CeReS preparation by approximately two-fold. The major inhibitory fraction that eluted from the DEAE column was further analyzed by tricine-SDS-PAGE and microbore reverse phase HPLC and shown to be homogeneous in nature. Two other fractions separated by DEAE HPLC, also devoid of protease activity, were shown to be inhibitory to cell proliferation and most likely represented modified relatives of the CeReS inhibitor. The highly purified CeReS was chemically characterized for amino acid and carbohydrate composition and the role of the carbohydrate in cell proliferation inhibition, stability, and protease resistance was assessed.

  9. Regulatory T Cells in Radiotherapeutic Responses

    PubMed Central

    Schaue, Dörthe; Xie, Michael W.; Ratikan, Josephine A.; McBride, William H.

    2012-01-01

    Radiation therapy (RT) can extend its influence in cancer therapy beyond what can be attributed to in-field cytotoxicity by modulating the immune system. While complex, these systemic effects can help tip the therapeutic balance in favor of treatment success or failure. Engagement of the immune system is generally through recognition of damage-associated molecules expressed or released as a result of tumor and normal tissue radiation damage. This system has evolved to discriminate pathological from physiological forms of cell death by signaling “danger.” The multiple mechanisms that can be evoked include a shift toward a pro-inflammatory, pro-oxidant microenvironment that can promote maturation of dendritic cells and, in cancer treatment, the development of effector T cell responses to tumor-associated antigens. Control over these processes is exerted by regulatory T cells (Tregs), suppressor macrophages, and immunosuppressive cytokines that act in consort to maintain tolerance to self, limit tissue damage, and re-establish tissue homeostasis. Unfortunately, by the time RT for cancer is initiated the tumor-host relationship has already been sculpted in favor of tumor growth and against immune-mediated mechanisms for tumor regression. Reversing this situation is a major challenge. However, recent data show that removal of Tregs can tip the balance in favor of the generation of radiation-induced anti-tumor immunity. The clinical challenge is to do so without excessive depletion that might precipitate serious autoimmune reactions and increase the likelihood of normal tissue complications. The selective modulation of Treg biology to maintain immune tolerance and control of normal tissue damage, while releasing the “brakes” on anti-tumor immune responses, is a worthy aim with promise for enhancing the therapeutic benefit of RT for cancer. PMID:22912933

  10. Cell proliferation inhibition in reduced gravity

    NASA Technical Reports Server (NTRS)

    Moos, P. J.; Fattaey, H. K.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Extended durations of spaceflight have been shown to be deleterious on an organismic level; however, mechanisms underlying cellular sensitivity to the gravitational environment remain to be elucidated. The majority of the gravitational studies to date indicates that cell regulatory pathways may be influenced by their gravitational environment. Still, few cell biology experiments have been performed in space flight and even fewer experiments have been repeated on subsequent flights. With flight opportunities on STS-50, 54, and 57, Sf9 cells were flown in the BioServe Fluids Processing Apparatus and cell proliferation was measured with and without exposure to a cell regulatory sialoglycopeptide (CeReS) inhibitor. Results from these flights indicate that the Sf9 cells grew comparable to ground controls, that the CeReS inhibitor bound to its specific receptor, and that its signal transduction cascade was not gravity sensitive.

  11. The water soluble ruthenium(II) organometallic compound [Ru(p-cymene)(bis(3,5 dimethylpyrazol-1-yl)methane)Cl]Cl suppresses triple negative breast cancer growth by inhibiting tumor infiltration of regulatory T cells.

    PubMed

    Montani, Maura; Pazmay, Gretta V Badillo; Hysi, Albana; Lupidi, Giulio; Pettinari, Riccardo; Gambini, Valentina; Tilio, Martina; Marchetti, Fabio; Pettinari, Claudio; Ferraro, Stefano; Iezzi, Manuela; Marchini, Cristina; Amici, Augusto

    2016-05-01

    Ruthenium compounds have become promising alternatives to platinum drugs by displaying specific activities against different cancers and favorable toxicity and clearance properties. Here, we show that the ruthenium(II) complex [Ru(p-cymene)(bis(3,5-dimethylpyrazol-1-yl)methane)Cl]Cl (UNICAM-1) exhibits potent in vivo antitumor effects. When administered as four-dose course, by repeating a single dose (52.4mgkg-1) every three days, UNICAM-1 significantly reduces the growth of A17 triple negative breast cancer cells transplanted into FVB syngeneic mice. Pharmacokinetic studies indicate that UNICAM-1 is rapidly eliminated from kidney, liver and bloodstream thanks to its high hydrosolubility, exerting excellent therapeutic activity with minimal side effects. Immunohistological analysis revealed that the efficacy of UNICAM-1, mainly relies on its capacity to reverse tumor-associated immune suppression by significantly reducing the number of tumor-infiltrating regulatory T cells. Therefore, UNICAM-1 appears very promising for the treatment of TNBC. PMID:27038531

  12. Fatostatin Inhibits Cancer Cell Proliferation by Affecting Mitotic Microtubule Spindle Assembly and Cell Division.

    PubMed

    Gholkar, Ankur A; Cheung, Keith; Williams, Kevin J; Lo, Yu-Chen; Hamideh, Shadia A; Nnebe, Chelsea; Khuu, Cindy; Bensinger, Steven J; Torres, Jorge Z

    2016-08-12

    The sterol regulatory element-binding protein (SREBP) transcription factors have become attractive targets for pharmacological inhibition in the treatment of metabolic diseases and cancer. SREBPs are critical for the production and metabolism of lipids and cholesterol, which are essential for cellular homeostasis and cell proliferation. Fatostatin was recently discovered as a specific inhibitor of SREBP cleavage-activating protein (SCAP), which is required for SREBP activation. Fatostatin possesses antitumor properties including the inhibition of cancer cell proliferation, invasion, and migration, and it arrests cancer cells in G2/M phase. Although Fatostatin has been viewed as an antitumor agent due to its inhibition of SREBP and its effect on lipid metabolism, we show that Fatostatin's anticancer properties can also be attributed to its inhibition of cell division. We analyzed the effect of SREBP activity inhibitors including Fatostatin, PF-429242, and Betulin on the cell cycle and determined that only Fatostatin possessed antimitotic properties. Fatostatin inhibited tubulin polymerization, arrested cells in mitosis, activated the spindle assembly checkpoint, and triggered mitotic catastrophe and reduced cell viability. Thus Fatostatin's ability to inhibit SREBP activity and cell division could prove beneficial in treating aggressive types of cancers such as glioblastomas that have elevated lipid metabolism and fast proliferation rates and often develop resistance to current anticancer therapies. PMID:27378817

  13. Novel Foxp3(-) IL-10(-) Regulatory T-cells Induced by B-Cells Alleviate Intestinal Inflammation in Vivo.

    PubMed

    Shao, Tzu-Yu; Hsu, Ling-Hui; Chien, Chien-Hui; Chiang, Bor-Luen

    2016-01-01

    Recent studies have revealed various Foxp3(-) regulatory T (Treg) cell subsets effectively protect mice from colitis. In the present study, we demonstrated that B cells induced a particular subset of regulatory T (Treg-of-B) cells, expressing programmed cell death 1 (PD-1), inducible costimulator (ICOS), lymphocyte-activation gene 3 (LAG3), glucocorticoid-induced tumor necrosis factor receptor (GITR), and OX-40, did not express Foxp3. Treg-of-B cells produced abundant levels of IL-10 and low levels of IL-4 and TGF-β. Adoptive transfer of Treg-of-B cells protected mice from CD4(+)CD45RB(hi) T-cell-induced colitis, including infiltration of leukocytes, depletion of goblet cells, epithelial hyperplasia, and inhibition of Th1 and Th17 cytokines. These features were similar to IL-10-producing type 1 regulatory T (Tr1) cells; however, IL-10-deficient Treg-of-B cells maintained their suppressive function in vitro as well as in vivo, while the regulation of Tr1 cells depended on IL-10. In conclusion, Treg-of-B cells protected against experimental colitis through an IL-10-independent mechanism. We reported a novel subpopulation of regulatory T cells was different from conventional Foxp3(+) Treg and IL-10-producing Tr1 cells. PMID:27581189

  14. Regulatory T Cells in Allogeneic Stem Cell Transplantation

    PubMed Central

    Nagler, Arnon

    2013-01-01

    Growing evidence suggests that cellular adoptive immunotherapy is becoming an attractive though challenging approach in regulating tumor immunity and alloresponses in clinical transplantation. Naturally arising CD4+CD25+Foxp3+ regulatory T cells (Treg) have emerged as a key component in this regard. Over the last decade, a large body of evidence from preclinical models has demonstrated their crucial role in auto- and tumor immunity and has opened the door to their “first-in-man” clinical application. Initial studies in clinical allogeneic stem cell transplantation are very encouraging and may pave the way for other applications. Further improvements in Treg ex vivo or in vivo expansion technologies will simplify their global clinical application. In this review, we discuss the current knowledge of Treg biology and their potential for cell-based immunotherapy in allogeneic stem cell transplantation. PMID:23737813

  15. The impact of regulatory T cells on T-cell immunity following hematopoietic cell transplantation

    PubMed Central

    Nguyen, Vu H.; Shashidhar, Sumana; Chang, Daisy S.; Ho, Lena; Kambham, Neeraja; Bachmann, Michael; Brown, Janice M.

    2008-01-01

    Regulatory T cells (Tregs) prevent graft-versus-host disease (GvHD) by inhibiting the proliferation and function of conventional T cells (Tcons). However, the impact of Tregs on T-cell development and immunity following hematopoietic cell transplantation (HCT) is unknown. Using a murine GvHD model induced by Tcons, we demonstrate that adoptive transfer of Tregs leads to (1) abrogration of GvHD, (2) preservation of thymic and peripheral lymph node architecture, and (3) an accelerated donor lymphoid reconstitution of a diverse TCR-Vβ repertoire. The resultant enhanced lymphoid reconstitution in Treg recipients protects them from lethal cytomegalovirus (MCMV) infection. By contrast, mice that receive Tcons alone have disrupted lymphoid organs from GvHD and remain lymphopenic with a restricted TCR-Vβ repertoire and rapid death on MCMV challenge. Lymphocytes from previously infected Treg recipients generate secondary response specific to MCMV, indicating long-term protective immunity with transferred Tregs. Thymectomy significantly reduces survival after MCMV challenge in Treg recipients compared with euthymic controls. Our results indicate that Tregs enhance immune reconstitution by preventing GvHD-induced damage of the thymic and secondary lymphoid microenvironment. These findings provide new insights into the role of Tregs in affording protection to lymphoid stromal elements important for T-cell immunity. PMID:17916743

  16. Mechanisms of regulatory volume increase in collecting duct cells.

    PubMed

    Fu, W J; Kuwahara, M; Cragoe, E J; Marumo, F

    1993-01-01

    To examine the mechanisms of cell volume regulation in response to hyperosmolality, segments of the inner stripe of rabbit outer medullary collecting duct (OMCDi) were perfused in vitro. The cross-sectional area of the tubule was monitored as an index of the relative cell volume. When luminal and basolateral osmolalities were increased from 290 to 390 mOsm simultaneously, the tubule cell shrank instantaneously and reswelled gradually, showing the so-called regulatory volume increase (RVI). Basolateral Na+ removal and addition of basolateral ethyl isopropyl amiloride (EIPA) decreased the RVI response by 76 and 66%, respectively. By contrast, apical Na+ removal had no effect on this response. RVI response was also inhibited by basolateral, but not luminal, Cl- removal (-63%), by total HCO3- removal (-74%), and by adding basolateral 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) (-62%). Intracellular pH did not change significantly during RVI. Vasopressin increased RVI response by 56%. However, this increase was abolished in the absence of basolateral Na+ and Cl-, and in the presence of basolateral EIPA and DIDS. These results suggest that major mechanisms responsible for RVI are Na(+)-H+ and Cl(-)-HCO3- exchange systems in the basolateral membrane, and that these systems are stimulated by vasopressin in rabbit OMCDi. PMID:8007444

  17. Unifying roles for regulatory T cells and inflammation in cancer

    PubMed Central

    Erdman, Susan E.; Rao, Varada P.; Olipitz, Werner; Taylor, Christie L.; Jackson, Erin A.; Levkovich, Tatiana; Lee, Chung-Wei; Horwitz, Bruce H.; Fox, James G.; Ge, Zhongming; Poutahidis, Theofilos

    2014-01-01

    Activities of CD4+ regulatory (TREG) cells restore immune homeostasis during chronic inflammatory disorders. Roles for TREG cells in inflammation-associated cancers, however, are paradoxical. It is widely believed that TREG function in cancer mainly to suppress protective anticancer responses. However, we demonstrate here that TREG cells also function to reduce cancer risk throughout the body by efficiently downregulating inflammation arising from the gastrointestinal (GI) tract. Building on a “hygiene hypothesis” model in which GI infections lead to changes in TREG that reduce immune-mediated diseases, here we show that gut bacteria-triggered TREG may function to inhibit cancer even in extraintestinal sites. Ability of bacteria-stimulated TREG to suppress cancer depends on interleukin (IL)-10, which serves to maintain immune homeostasis within bowel and support a protective antiinflammatory TREG phenotype. However, under proinflammatory conditions, TREG may fail to provide antiinflammatory protection and instead contribute to a T helper (Th)-17-driven procarcinogenic process; a cancer state that is reversible by downregulation of inflammation. Consequently, hygienic individuals with a weakened IL-10 and TREG-mediated inhibitory loop are highly susceptible to the carcinogenic consequences of elevated IL-6 and IL-17 and show more frequent inflammation-associated cancers. Taken together, these data unify seemingly divergent disease processes such as autoimmunity and cancer and help explain the paradox of TREG and inflammation in cancer. Enhancing protective TREG functions may promote healthful longevity and significantly reduce risk of cancer. PMID:19795459

  18. Inhibition of medulloblastoma cell invasion by Slit.

    PubMed

    Werbowetski-Ogilvie, T E; Seyed Sadr, M; Jabado, N; Angers-Loustau, A; Agar, N Y R; Wu, J; Bjerkvig, R; Antel, J P; Faury, D; Rao, Y; Del Maestro, R F

    2006-08-24

    Invasion of brain tumor cells has made primary malignant brain neoplasms among the most recalcitrant to therapeutic strategies. We tested whether the secreted protein Slit2, which guides the projection of axons and developing neurons, could modulate brain tumor cell invasion. Slit2 inhibited the invasion of medulloblastoma cells in a variety of in vitro models. The effect of Slit2 was inhibited by the Robo ectodomain. Time-lapse videomicroscopy indicated that Slit2 reduced medulloblastoma invasion rate without affecting cell direction or proliferation. Both medulloblastoma and glioma tumors express Robo1 and Slit2, but only medulloblastoma invasion is inhibited by recombinant Slit2 protein. Downregulation of activated Cdc42 may contribute to this differential response. Our findings reinforce the concept that neurodevelopmental cues such as Slit2 may provide insights into brain tumor invasion. PMID:16636676

  19. Roles for Inflammation and Regulatory T Cells in Colon Cancer

    PubMed Central

    Erdman, Susan E.; Poutahidis, Theofilos

    2014-01-01

    Risk for developing cancer rises substantially as a result of poorly regulated inflammatory responses to pathogenic bacterial infections. Anti-inflammatory CD4+ regulatory cells (TREG) function to restore immune homeostasis during chronic inflammatory disorders. It seems logical that TREG cells would function to reduce risk of inflammation-associated cancer in the bowel by down-regulating inflammation. It is widely believed, however, that TREG function in cancer mainly to suppress protective anticancer inflammatory responses. Thus roles for inflammation, TREG cells, and gut bacteria in cancer are paradoxical and are the subject of controversy. Our accumulated data build upon the “hygiene hypothesis” model in which gastrointestinal (GI) infections lead to changes in TREG that reduce inflammation-associated diseases. Ability of TREG to inhibit or suppress cancer depends upon gut bacteria and IL-10, which serve to maintain immune balance and a protective anti-inflammatory TREG phenotype. However, under poorly regulated pro-inflammatory conditions, TREG fail to inhibit and may instead contribute to a T helper (Th)-17-driven procarcinogenic process, a cancer state that is reversible by down-regulation of inflammation and interleukin (IL)-6. Consequently, hygienic individuals with a weakened IL-10– and TREG–mediated inhibitory loop are highly susceptible to the carcinogenic consequences of elevated inflammation and show more frequent inflammation-associated cancers. Taken together, these data help explain the paradox of inflammation and TREG in cancer and indicate that targeted stimulation of TREG may promote health and significantly reduce risk of cancer. PMID:20019355

  20. Andrographolide inhibits multiple myeloma cells by inhibiting the TLR4/NF-κB signaling pathway.

    PubMed

    Gao, Hui; Wang, Jianrong

    2016-02-01

    Andrographolide is an active component from the extract of Andrographis paniculata [(Burm.f) Nees], a medicinal plant from the Acanthaceae family. Pharmacological studies have revealed that andrographolide possesses anti-bacterial, anti-inflammatory, anti-viral, immune regulatory and hepatoprotective properties, and is efficacious in the treatment of cardiovascular diseases, while exhibiting low toxicity and low cost. The present study aimed to determine the inhibitory effects of andrographolide on the growth of multiple myeloma (MM) cells and its possible impact on the Toll-like receptor (TLR)4/nuclear factor (NF)-κB signaling pathway. Cell proliferation was detected using an MTT assay, cellular apoptosis was measured using flow cytometry, and caspase-9/3 activation were assessed using colorimetric assay kits. Furthermore, TLR4 and NF-κB protein expression was determined by western blot analysis. The results revealed that andrographolide reduced the proliferation, while increasing cellular apoptosis and caspase-9/3 activation of MM cells, in addition to downregulating the expression of TLR4 and NF-κB protein. Of note, TLR4- or NF-κB-targeting small-interfering (si)RNA enhanced the andrographolide-induced inhibition of cell proliferation and induction of apoptosis of MM cells. The results of the present study therefore suggested that andrographolide inhibited multiple myeloma cells via the TLR4/NF-κB signaling pathway. PMID:26707811

  1. Regulatory T Cells and Their Role in Animal Disease.

    PubMed

    Veiga-Parga, T

    2016-07-01

    In humans and mouse models, Foxp3(+) regulatory T cells are known to control all aspects of immune responses. However, only limited information exists on these cells' role in diseases of other animals. In this review, we cover the most important features and different types of regulatory T cells, which include those that are thymus-derived and peripherally induced, the mechanisms by which they control immune responses by targeting effector T cells and antigen-presenting cells, and most important, their role in animal health and diseases including cancer, infections, and other conditions such as hypersensitivities and autoimmunity. Although the literature regarding regulatory T cells in domestic animal species is still limited, multiple articles have recently emerged and are discussed. Moreover, we also discuss the evidence suggesting that regulatory T cells might limit the magnitude of effector responses, which can have either a positive or negative result, depending on the context of animal and human disease. In addition, the issue of plasticity is discussed because plasticity in regulatory T cells can result in the loss of their protective function in some microenvironments during disease. Lastly, the manipulation of regulatory T cells is discussed in assessing the possibility of their use as a treatment in the future. PMID:26945003

  2. Monoclonal regulatory T cells provide insights into T cell suppression

    PubMed Central

    Gubser, Céline; Schmaler, Mathias; Rossi, Simona W.; Palmer, Ed

    2016-01-01

    Regulatory T cells (Tregs) have a crucial role in maintaining lymphocyte homeostasis. However an understanding of how Tregs function at a cellular and molecular level has not yet been fully elucidated. Here, we make use of a T cell receptor (TCR) transgenic, Rag−/− mouse expressing a Forkhead-Box-Protein P3 (Foxp3) transgene. This mouse provides a source of monoclonal CD4+ Foxp3+ T cells with a defined specificity. Here we show that monoclonal B3K506 Tregs are functional in vitro and in vivo and clearly require cognate antigen to be suppressive. We further show that the strength of Treg stimulation determines the strength of Treg mediated suppression. Finally we analysed various suppressive mechanisms used by monoclonal Tregs and found that Treg-Tconv proximity is a parameter, which correlates with enhanced suppression. PMID:27210828

  3. Monoclonal regulatory T cells provide insights into T cell suppression.

    PubMed

    Gubser, Céline; Schmaler, Mathias; Rossi, Simona W; Palmer, Ed

    2016-01-01

    Regulatory T cells (Tregs) have a crucial role in maintaining lymphocyte homeostasis. However an understanding of how Tregs function at a cellular and molecular level has not yet been fully elucidated. Here, we make use of a T cell receptor (TCR) transgenic, Rag(-/-) mouse expressing a Forkhead-Box-Protein P3 (Foxp3) transgene. This mouse provides a source of monoclonal CD4(+) Foxp3(+) T cells with a defined specificity. Here we show that monoclonal B3K506 Tregs are functional in vitro and in vivo and clearly require cognate antigen to be suppressive. We further show that the strength of Treg stimulation determines the strength of Treg mediated suppression. Finally we analysed various suppressive mechanisms used by monoclonal Tregs and found that Treg-Tconv proximity is a parameter, which correlates with enhanced suppression. PMID:27210828

  4. Proceedings: International Regulatory Considerations on Development Pathways for Cell Therapies

    PubMed Central

    Tsokas, Katherine; Viswanathan, Sowmya; Zhang, Jiwen; Priest, Catherine; Pearce, Jonathan; Mount, Natalie

    2014-01-01

    Regenerative medicine is a rapidly evolving field that faces novel scientific and regulatory challenges. In September 2013, the International Workshop on Regulatory Pathways for Cell Therapies was convened to discuss the nature of these challenges and potential solutions and to highlight opportunities for potential convergence between different regulatory bodies that might assist the field’s development. The workshop discussions generated potentially actionable steps in five main areas that could mitigate cell therapy development pathway risk and accelerate moving promising therapies to patients. These included the need for convergence of regulatory guidelines on donor eligibility and suitability of lines for use in clinical trials and subsequent commercialization for cell therapies to move forward on a global basis; the need to challenge and encourage investigators in the regenerative medicine field to share information and provide examples of comparability studies related to master cell banks; the need for convergence of guidelines across regulatory jurisdictions on requirements for tumorigenicity studies, based on particular cell types and on biodistribution studies; the need to increase transparency in sharing clinical trial information more broadly and disseminating results more rapidly; and the need to establish a forum for sharing the experiences of various approaches being developed to expedite regulatory approvals and access for patients to innovative cell and regenerative therapies in the different regulatory jurisdictions and to assess their potential strengths and weaknesses. PMID:25038248

  5. Human regulatory T cells suppress proliferation of B lymphoma cells.

    PubMed

    Grygorowicz, Monika Anna; Biernacka, Marzena; Bujko, Mateusz; Nowak, Eliza; Rymkiewicz, Grzegorz; Paszkiewicz-Kozik, Ewa; Borycka, Ilona Sara; Bystydzienski, Zbigniew; Walewski, Jan; Markowicz, Sergiusz

    2016-08-01

    Activated regulatory T cells (Tregs) suppress proliferation and differentiation of normal B cells. In our study, allogeneic polyclonal CD4 (+) CD25 (+) Tregs and CD4 (+) CD25 (+) CD127(lo)Tregs expanded in vitro in the presence of rapamycin and low dose IL-2 suppressed proliferation of 11 out of 12 established lymphoma B-cell lines. The effect of expanded CD4 (+) CD25 (+) Tregs on survival of freshly isolated lymphoma B cells maintained in culture with soluble multimeric CD40L and IL-4 was variable across lymphoma entities. The survival of freshly isolated follicular lymphoma cells usually decreased in cocultures with CD4 (+) CD25 (+) Tregs. Treg effect on chronic lymphocytic leukemia/small lymphocytic lymphoma cells ranged from suppression to help in individual patients. CD4 (+) CD25 (+) Tregs or CD4 (+) CD25 (+) CD127(lo)Tregs expanded ex vivo with rapamycin could be used to suppress regrowth of residual lymphoma after autologous hematopoietic cell transplantation (HCT), and to counteract both graft-versus-host disease and lymphoma re-growth after allogeneic HCT in select patients with lymphoma susceptible to the regulation by Tregs. PMID:26758248

  6. Characterization of Dendritic Cell and Regulatory T Cell Functions against Mycobacterium tuberculosis Infection

    PubMed Central

    Morris, Devin; Gonzalez, Brenda; Khurasany, Melissa; Kassissa, Christine; Luong, Jennifer; Kasko, Sarah; Pandya, Shalin; Chu, Michael; Chi, Po-Ting; Bui, Steven; Guerra, Carlos; Chan, John; Venketaraman, Vishwanath

    2013-01-01

    Glutathione (GSH) is a tripeptide that regulates intracellular redox and other vital aspects of cellular functions. GSH plays a major role in enhancing the immune system. Dendritic cells (DCs) are potent antigen presenting cells that participate in both innate and acquired immune responses against microbial infections. Regulatory T cells (Tregs) play a significant role in immune homeostasis. In this study, we investigated the effects of GSH in enhancing the innate and adaptive immune functions of DCs against Mycobacterium tuberculosis (M. tb) infection. We also characterized the functions of the sub-populations of CD4+T cells such as Tregs and non-Tregs in modulating the ability of monocytes to control the intracellular M. tb infection. Our results indicate that GSH by its direct antimycobacterial activity inhibits the growth of intracellular M. tb inside DCs. GSH also increases the expressions of costimulatory molecules such as HLA-DR, CD80 and CD86 on the cell surface of DCs. Furthermore, GSH-enhanced DCs induced a higher level of T-cell proliferation. We also observed that enhancing the levels of GSH in Tregs resulted in downregulation in the levels of IL-10 and TGF-β and reduction in the fold growth of M. tb inside monocytes. Our studies demonstrate novel regulatory mechanisms that favor both innate and adaptive control of M. tb infection. PMID:23762843

  7. CD101 inhibits the expansion of colitogenic T cells.

    PubMed

    Schey, R; Dornhoff, H; Baier, J L C; Purtak, M; Opoka, R; Koller, A K; Atreya, R; Rau, T T; Daniel, C; Amann, K; Bogdan, C; Mattner, J

    2016-09-01

    CD101 exerts negative-costimulatory effects in vitro, but its function in vivo remains poorly defined. CD101 is abundantly expressed on lymphoid and myeloid cells in intestinal tissues, but absent from naïve splenic T cells. Here, we assessed the impact of CD101 on the course of inflammatory bowel disease (IBD). Using a T-cell transfer model of chronic colitis, we found that in recipients of naïve T cells from CD101(+/+) donors up to 30% of the recovered lymphocytes expressed CD101, correlating with an increased interleukin (IL)-2-mediated FoxP3 expression. Transfer of CD101(-/-) T cells caused more severe colitis and was associated with an expansion of IL-17-producing T cells and an enhanced expression of IL-2Rα/β independently of FoxP3. The co-transfer of naïve and regulatory T cells (Treg) protected most effectively from colitis, when both donor and recipient mice expressed CD101. Although the expression of CD101 on T cells was sufficient for Treg-function and the inhibition of T-cell proliferation, sustained IL-10 production required additional CD101 expression by myeloid cells. Finally, in patients with IBD a reduced CD101 expression on peripheral and intestinal monocytes and CD4(+) T cells correlated with enhanced IL-17 production and disease activity. Thus, CD101 deficiency is a novel marker for progressive colitis and potential target for therapeutic intervention. PMID:26813346

  8. Role of dendritic cells in the induction of regulatory T cells

    PubMed Central

    2011-01-01

    Dendritic cells (DCs) play a key role in initiating immune responses and maintaining immune tolerance. In addition to playing a role in thymic selection, DCs play an active role in tolerance under steady state conditions through several mechanisms which are dependent on IL-10, TGF-β, retinoic acid, indoleamine-2,3,-dioxygenase along with vitamin D. Several of these mechanisms are employed by DCs in induction of regulatory T cells which are comprised of Tr1 regulatory T cells, natural and inducible foxp3+ regulatory T cells, Th3 regulatory T cells and double negative regulatory T cells. It appears that certain DC subsets are highly specialized in inducing regulatory T cell differentiation and in some tissues the local microenvironment plays a role in driving DCs towards a tolerogenic response. In this review we discuss the recent advances in our understanding of the mechanisms underlying DC driven regulatory T cell induction. PMID:21711933

  9. How tolerogenic dendritic cells induce regulatory T cells

    PubMed Central

    Maldonado, Roberto A.; von Andrian, Ulrich H.

    2010-01-01

    Since their discovery by Steinman and Cohn in 1973, dendritic cells (DCs) have become increasingly recognized for their crucial role as regulators of innate and adaptive immunity. DCs are exquisitely adept at acquiring, processing and presenting antigens to T cells. They also adjust the context (and hence the outcome) of antigen presentation in response to a plethora of environmental inputs that signal the occurence of pathogens or tissue damage. Such signals generally boost DC maturation, which promotes their migration from peripheral tissues into and within secondary lymphoid organs and their capacity to induce and regulate effector T cell responses. Conversely, more recent observations indicate that DCs are also crucial to ensure immunological peace. Indeed, DCs constantly present innocuous self and non-self antigens in a fashion that promotes tolerance, at least in part, through the control of regulatory T cells (Tregs). Tregs are specialized T cells that exert their immuno-suppressive function through a variety of mechanisms affecting both DCs and effector cells. Here, we review recent advances in our understanding of the relationship between tolerogenic DCs and Tregs. PMID:21056730

  10. Bach2 represses plasma cell gene regulatory network in B cells to promote antibody class switch

    PubMed Central

    Muto, Akihiko; Ochiai, Kyoko; Kimura, Yoshitaka; Itoh-Nakadai, Ari; Calame, Kathryn L; Ikebe, Dai; Tashiro, Satoshi; Igarashi, Kazuhiko

    2010-01-01

    Two transcription factors, Pax5 and Blimp-1, form a gene regulatory network (GRN) with a double-negative loop, which defines either B-cell (Pax5 high) or plasma cell (Blimp-1 high) status as a binary switch. However, it is unclear how this B-cell GRN registers class switch DNA recombination (CSR), an event that takes place before the terminal differentiation to plasma cells. In the absence of Bach2 encoding a transcription factor required for CSR, mouse splenic B cells more frequently and rapidly expressed Blimp-1 and differentiated to IgM plasma cells as compared with wild-type cells. Genetic loss of Blimp-1 in Bach2−/− B cells was sufficient to restore CSR. These data with mathematical modelling of the GRN indicate that Bach2 achieves a time delay in Blimp-1 induction, which inhibits plasma cell differentiation and promotes CSR (Delay-Driven Diversity model for CSR). Reduction in mature B-cell numbers in Bach2−/− mice was not rescued by Blimp-1 ablation, indicating that Bach2 regulates B-cell differentiation and function through Blimp-1-dependent and -independent GRNs. PMID:20953163

  11. Regulatory T cells: present facts and future hopes.

    PubMed

    Becker, Christian; Stoll, Sabine; Bopp, Tobias; Schmitt, Edgar; Jonuleit, Helmut

    2006-09-01

    Naturally occurring CD4(+)CD25(+)Foxp3(+) regulatory T cells and several subsets of induced suppressor T cells are key players of the immune tolerance network and control the induction and effector phase of our immunological defense system. These T cell populations actively control the properties of other immune cells by suppressing their functional activity to prevent autoimmunity and transplant rejection but also influence the immune response to allergens as well as against tumor cells and pathogens. Even though we are far from completely understanding the molecular and cellular mechanisms that manage the different regulatory T cell populations, increasing evidence exists about their functional importance. The knowledge on their induction and activation opens the possibility for their selective manipulation in vivo as an attractive approach for an immunotherapy of unwanted immune responses. This review summarizes this knowledge and discusses the potential of regulatory T cells for novel immunointervention strategies in the future. PMID:16715254

  12. The regulatory sciences for stem cell-based medicinal products.

    PubMed

    Yuan, Bao-Zhu; Wang, Junzhi

    2014-06-01

    Over the past few years, several new achievements have been made from stem cell studies, many of which have moved up from preclinical stages to early, or from early to middle or late, stages thanks to relatively safe profile and preliminary evidence of effectiveness. Moreover, some stem cell-based products have been approved for marketing by different national regulatory authorities. However, many critical issues associated mainly with incomplete understanding of stem cell biology and the relevant risk factors, and lack of effective regulations still exist and need to be urgently addressed, especially in countries where establishment of appropriate regulatory system just commenced. More relevantly, the stem cell regulatory sciences need to be established or improved to more effectively evaluate quality, safety and efficacy of stem cell products, and for building up the appropriate regulatory framework. In this review, we summarize some new achievements in stem cell studies, especially the preclinical and clinical studies, the existing regulations, and the associated challenges, and we then propose some considerations for improving stem cell regulatory sciences with a goal of promoting the steadfast growth of the well-regulated stem cell therapies abreast of evolvement of stem cell sciences and technologies. PMID:24733351

  13. Inhibition of the proteasome induces cell cycle arrest and apoptosis in mantle cell lymphoma cells.

    PubMed

    Bogner, Christian; Ringshausen, Ingo; Schneller, Folker; Fend, Falko; Quintanilla-Martinez, Leticia; Häcker, Georg; Goetze, Katharina; Oostendorp, Robert; Peschel, Christian; Decker, Thomas

    2003-07-01

    Mantle cell lymphoma (MCL) is a distinctive non-Hodgkin's lymphoma subtype, characterized by overexpression of cyclin D1 as a consequence of the chromosomal translocation t(11;14)(q13;q32). MCL remains an incurable disease, combining the unfavourable clinical features of aggressive and indolent lymphomas. The blastic variant of MCL, which is often associated with additional cytogenetic alterations, has an even worse prognosis and new treatment options are clearly needed. The present study investigated the effect of a specific proteasome inhibitor, lactacystin, on cell cycle progression and apoptosis in two lymphoma cell lines harbouring the t(11;14)(q13;q32) and additional cytogenetic alterations, including p53 mutation (NCEB) and p16 deletion (Granta 519). Granta cells were more susceptible to inhibition of the proteasome with respect to inhibition of proliferation and apoptosis induction. No changes were observed in the expression levels of the G1 regulatory molecules cyclin D1 and cdk4, but cell cycle arrest and apoptosis induction was accompanied by accumulation of the cdk inhibitor p21 in both cell lines. Increased p53 expression was only observed in Granta cells with wild-type p53. Cleavage of procaspase-3 and -9 was observed but cleavage of procaspase-8 was not involved in apoptosis induction. The proapoptotic effect of lactacystin was reversed by pretreatment with the pancaspase inhibitor zVAD.fmk. Lactacystin was also effective in inducing apoptosis in lymphoma cells from MCL patients. We conclude that inhibition of the proteasome might be a promising therapeutic approach for this incurable disease. PMID:12846895

  14. Inhibition of cell-cell binding by lipid assemblies

    DOEpatents

    Nagy, Jon O.; Bargatze, Robert F.

    2001-05-22

    This invention relates generally to the field of therapeutic compounds designed to interfere between the binding of ligands and their receptors on cell surface. More specifically, it provides products and methods for inhibiting cell migration and activation using lipid assemblies with surface recognition elements that are specific for the receptors involved in cell migration and activation.

  15. A Lactobacillus rhamnosus Strain Induces a Heme Oxygenase Dependent Increase in Foxp3+ Regulatory T Cells

    PubMed Central

    Karimi, Khalil; Kandiah, Nalaayini; Chau, Jessie; Bienenstock, John; Forsythe, Paul

    2012-01-01

    We investigated the consequences of feeding with a Lactobacillus species on the immune environment in GALT, and the role of dendritic cells and heme oxygenase-1 in mediating these responses. Feeding with a specific strain of Lactobacillus rhamnosus induced a significant increase in CD4+CD25+Foxp3+ functional regulatory T cells in GALT. This increase was greatest in the mesenteric lymph nodes and associated with a marked decrease in TNF and IFNγ production. Dendritic cell regulatory function and HO-1 expression was also increased. The increase in Foxp3+ T cells could be prevented by treatment with a heme oxygenase inhibitor. However, neither inhibition of heme oxygenase nor blockade of IL-10 and TGFβ prevented the inhibition of inflammatory cytokine production. In conclusion Lactobacillus feeding induced a tolerogenic environment in GALT. HO-1 was critical to the enhancement of Foxp3+ regulatory T cells while additional, as yet unknown, pathways were involved in the down-regulation of inflammatory cytokine production by T cells. PMID:23077634

  16. Treatment of ongoing autoimmune encephalomyelitis with activated B-cell progenitors maturing into regulatory B cells.

    PubMed

    Korniotis, Sarantis; Gras, Christophe; Letscher, Hélène; Montandon, Ruddy; Mégret, Jérôme; Siegert, Stefanie; Ezine, Sophie; Fallon, Padraic G; Luther, Sanjiv A; Fillatreau, Simon; Zavala, Flora

    2016-01-01

    The influence of signals perceived by immature B cells during their development in bone marrow on their subsequent functions as mature cells are poorly defined. Here, we show that bone marrow cells transiently stimulated in vivo or in vitro through the Toll-like receptor 9 generate proB cells (CpG-proBs) that interrupt experimental autoimmune encephalomyelitis (EAE) when transferred at the onset of clinical symptoms. Protection requires differentiation of CpG-proBs into mature B cells that home to reactive lymph nodes, where they trap T cells by releasing the CCR7 ligand, CCL19, and to inflamed central nervous system, where they locally limit immunopathogenesis through interleukin-10 production, thereby cooperatively inhibiting ongoing EAE. These data demonstrate that a transient inflammation at the environment, where proB cells develop, is sufficient to confer regulatory functions onto their mature B-cell progeny. In addition, these properties of CpG-proBs open interesting perspectives for cell therapy of autoimmune diseases. PMID:27396388

  17. Mutant KRAS Conversion of Conventional T Cells into Regulatory T Cells.

    PubMed

    Zdanov, Stephanie; Mandapathil, Magis; Abu Eid, Rasha; Adamson-Fadeyi, Saudat; Wilson, Willie; Qian, Jiahua; Carnie, Andrea; Tarasova, Nadya; Mkrtichyan, Mikayel; Berzofsky, Jay A; Whiteside, Theresa L; Khleif, Samir N

    2016-04-01

    Constitutive activation of theKRASoncogene in human malignancies is associated with aggressive tumor growth and poor prognosis. Similar to other oncogenes,KRASacts in a cell-intrinsic manner to affect tumor growth or survival. However, we describe here a different, cell-extrinsic mechanism through which mutant KRAS contributes to tumor development. Tumor cells carrying mutated KRAS induced highly suppressive T cells, and silencing KRAS reversed this effect. Overexpression of the mutantKRAS(G12V)gene in wild-type KRAS tumor cells led to regulatory T-cell (Treg) induction. We also demonstrate that mutant KRAS induces the secretion of IL10 and transforming growth factor-β1 (both required for Treg induction) by tumor cells through the activation of the MEK-ERK-AP1 pathway. Finally, we report that inhibition of KRAS reduces the infiltration of Tregs in KRAS-driven lung tumorigenesis even before tumor formation. This cell-extrinsic mechanism allows tumor cells harboring a mutantKRASoncogene to escape immune recognition. Thus, an oncogene can promote tumor progression independent of its transforming activity by increasing the number and function of Tregs. This has a significant clinical potential, in which targeting KRAS and its downstream signaling pathways could be used as powerful immune modulators in cancer immunotherapy.Cancer Immunol Res; 4(4); 354-65. ©2016 AACR. PMID:26880715

  18. IL-10-producing type 1 regulatory T cells and allergy.

    PubMed

    Wu, Kui; Bi, Yutian; Sun, Kun; Wang, Changzheng

    2007-08-01

    As an important subset of regulatory T (Treg) cells, IL-10-producing type 1 regulatory T cells (Tr1), have some different features to thymic-derived naturally occurring CD4+CD25+Foxp3+ Treg cells(nTreg cells). Similar to nTreg cells, Tr1 also play important roles in the control of allergic inflammation in several ways. There is a fine balance between Tr1 and Th2 responses in healthy subjects. Skewing of allergic-specific effector T cells to a Tr1 phenotype appears to be a critical event in successful allergen-specific immunotherapy and glucocorticoids and beta2-agonists treatment. Tr1 suppress Th2 cells and effector cells of allergic inflammation, such as eosinophils, mast cells, basophils, through producing IL-10, and perhaps TGF-beta. Understanding of Tr1 may be helpful in developing new strategies for treatment of allergic diseases. PMID:17764617

  19. Special regulatory T cell review: The resurgence of the concept of contrasuppression in immunoregulation

    PubMed Central

    Lehner, Thomas

    2008-01-01

    The original concept of contrasuppression (CS) is evident in many immunoregulatory mechanisms. Inhibition of suppressor activity – CS – may be critical in microbial infection and autoimmunity. The major cellular interactions involved in suppression are the CD25+ FoxP3+ CD4+ T regulatory cells, programmed death-1 (PD-1) : PD-L1/L2 and cytotoxic T lymphocyte antigen-4 (CTLA-4) : CD80/86 pathways. These cellular functions are affected by dendritic cells (DC) and a complex array of cytokines of which interleukin (IL)-2, IL-10, IL-6 and transforming growth factor-β (TGF-β) are especially significant. Inhibition of regulatory cells, suppressor pathways or cytokines, is consistent with CS and can be attributed to IL-6, IL-2, PD-1 or PD-L-1 antibodies, blockade of CTLA-4 : CD80/86 pathway, inhibition of CD40–CD40L pathways, and TGF-β, IL-10 antibodies. Contrasuppression may regulate innate immunity by Toll-like receptor expressed not only in non-cognate DC, monocytes, natural killer cells and γδ T cells but also in adaptive T cells. Furthermore, cross-talk between innate and adaptive immunity may be facilitated by contrasuppressor activity. ‘‘What’s in a name? That which we call a rose by any other name would smell as sweet.’’ From Romeo and Juliet (II, 47–8) W. Shakespeare PMID:18154618

  20. Special regulatory T cell review: The resurgence of the concept of contrasuppression in immunoregulation.

    PubMed

    Lehner, Thomas

    2008-01-01

    The original concept of contrasuppression (CS) is evident in many immunoregulatory mechanisms. Inhibition of suppressor activity--CS--may be critical in microbial infection and autoimmunity. The major cellular interactions involved in suppression are the CD25+ FoxP3+ CD4+ T regulatory cells, programmed death-1 (PD-1) : PD-L1/L2 and cytotoxic T lymphocyte antigen-4 (CTLA-4) : CD80/86 pathways. These cellular functions are affected by dendritic cells (DC) and a complex array of cytokines of which interleukin (IL)-2, IL-10, IL-6 and transforming growth factor-beta (TGF-beta) are especially significant. Inhibition of regulatory cells, suppressor pathways or cytokines, is consistent with CS and can be attributed to IL-6, IL-2, PD-1 or PD-L-1 antibodies, blockade of CTLA-4 : CD80/86 pathway, inhibition of CD40-CD40L pathways, and TGF-beta, IL-10 antibodies. Contrasuppression may regulate innate immunity by Toll-like receptor expressed not only in non-cognate DC, monocytes, natural killer cells and gammadelta T cells but also in adaptive T cells. Furthermore, cross-talk between innate and adaptive immunity may be facilitated by contrasuppressor activity. ''What's in a name? That which we call a rose by any other name would smell as sweet.'' From Romeo and Juliet (II, 47-8) W. Shakespeare. PMID:18154618

  1. Regulatory T cells in tumor-associated tertiary lymphoid structures suppress anti-tumor T cell responses

    PubMed Central

    Joshi, Nikhil S.; Akama-Garren, Elliot H.; Lu, Yisi; Lee, Da-Yae; Chang, Gregory P.; Li, Amy; DuPage, Michel; Tammela, Tuomas; Kerper, Natanya R.; Farago, Anna F.; Robbins, Rebecca; Crowley, Denise M.; Bronson, Roderick T.; Jacks, Tyler

    2016-01-01

    SUMMARY Infiltration of regulatory T (Treg) cells into many tumor types correlates with poor patient prognoses. However, mechanisms of intratumoral Treg cell function remain to be elucidated. We investigated Treg cell function in a genetically-engineered mouse lung adenocarcinoma model and found Treg cells suppress anti-tumor responses in tumor-associated tertiary lymphoid structures (TA-TLS). TA-TLS have been described in human lung cancers, but their function remains to be determined. TLS in this model were spatially associated with >90% of tumors and facilitated interactions between T cells and tumor-antigen presenting dendritic cells (DCs). Costimulatory ligand expression by DCs and T cell proliferation rates increased in TA-TLS upon Treg cell depletion, leading to tumor destruction. Thus, we propose Treg cells in TA-TLS can inhibit endogenous immune responses against tumors, and targeting these cells may provide therapeutic benefit for cancer patients. PMID:26341400

  2. Control of regulatory T cell lineage commitment and maintenance

    PubMed Central

    Josefowicz, Steven Z.; Rudensky, Alexander

    2015-01-01

    Foxp3-expressing regulatory T (Treg) cells suppress pathology mediated by immune responses against self and foreign antigens, and commensal microorganisms. Sustained expression of the transcription factor Foxp3, a key distinguishing feature of Treg cells, is required for their differentiation and suppressor function. In addition, Foxp3 expression prevents deviation of Treg cells into effector T cell lineages and confers dependence of Treg cell survival and expansion on growth factors, foremost interleukin-2, provided by activated effector T cells. In this review we discuss Treg cell differentiation and maintenance with a particular emphasis on molecular regulation of Foxp3 expression, arguably a key to mechanistic understanding of biology of regulatory T cells. PMID:19464984

  3. Differentially modulated dendritic cells induce regulatory T cells with different characteristics.

    PubMed

    Roelen, Dave L; van den Boogaardt, Daniëlle E M; van Miert, Paula P M C; Koekkoek, Karin; Offringa, Rienk; Claas, Frans H J

    2008-07-01

    Dexamethason (DEX) treated DC display several features that establish them as candidates for specific allogeneic tolerance induction. We report the results of in vitro studies of polarization of the alloimmune T cell response with two types of differentially modulated human DC. Both DEX treated DC triggered by LPS for 6 h (DEX6-DC) and DEX treated DC triggered by LPS for 48 h (DEX48-DC) acquired low levels of costimulatory, adhesion, and MHC class II molecules compared with mature DC (mDC). In contrast to mDC, both DEX6-DC and DEX48-DC did not produce any IL-12. DEX6-DC were able to produce significant amounts of IL-10 whereas DEX48-DC did not actively produce IL-10. Conversely, the induction of IL-10 producing cells was significantly increased when PBL were stimulated with DEX48-DC compared with DEX6-DC. Both stimulation of PBL with DEX6-DC and DEX48-DC led to the induction of cell populations able to suppress the proliferative alloimmune response of primed T cells in a cell-cell contact independent and antigen-nonspecific manner. Tregs obtained after stimulation with DEX48-DC were also able to inhibit the IFN-gamma production of the effector cells and this effect could be blocked by anti-IL-10. Tregs induced by DEX6-DC produced similar amounts of IL-10, yet were not able to inhibit IFN-gamma production of the effector T cells, indicating a different mechanism. In summary, we show that differential modulation of DC results in the induction of different populations of regulatory T cells. PMID:18639635

  4. Borna disease virus nucleoprotein inhibits type I interferon induction through the interferon regulatory factor 7 pathway

    SciTech Connect

    Song, Wuqi; Kao, Wenping; Zhai, Aixia; Qian, Jun; Li, Yujun; Zhang, Qingmeng; Zhao, Hong; Hu, Yunlong; Li, Hui; Zhang, Fengmin

    2013-09-06

    Highlights: •IRF7 nuclear localisation was inhibited by BDV persistently infected. •BDV N protein resistant to IFN induction both in BDV infected OL cell and N protein plasmid transfected OL cell. •BDV N protein is related to the inhibition of IRF7 nuclear localisation. -- Abstract: The expression of type I interferon (IFN) is one of the most potent innate defences against viral infection in higher vertebrates. Borna disease virus (BDV) establishes persistent, noncytolytic infections in animals and in cultured cells. Early studies have shown that the BDV phosphoprotein can inhibit the activation of type I IFN through the TBK1–IRF3 pathway. The function of the BDV nucleoprotein in the inhibition of IFN activity is not yet clear. In this study, we demonstrated IRF7 activation and increased IFN-α/β expression in a BDV-persistently infected human oligodendroglia cell line following RNA interference-mediated BDV nucleoprotein silencing. Furthermore, we showed that BDV nucleoprotein prevented the nuclear localisation of IRF7 and inhibited endogenous IFN induction by poly(I:C), coxsackie virus B3 and IFN-β. Our findings provide evidence for a previously undescribed mechanism by which the BDV nucleoprotein inhibits type I IFN expression by interfering with the IRF7 pathway.

  5. IL-10-producing regulatory B10 cells ameliorate collagen-induced arthritis via suppressing Th17 cell generation.

    PubMed

    Yang, Min; Deng, Jun; Liu, Yang; Ko, King-Hung; Wang, Xiaohui; Jiao, Zhijun; Wang, Shengjun; Hua, Zichun; Sun, Lingyun; Srivastava, Gopesh; Lau, Chak-Sing; Cao, Xuetao; Lu, Liwei

    2012-06-01

    IL-10-producing CD1d(hi)CD5(+) B cells, also known as B10 cells, have been shown to possess a regulatory function in the inhibition of immune responses, but whether and how B10 cells suppress the development of autoimmune arthritis remain largely unclear. In this study, we detected significantly decreased numbers of IL-10-producing B cells, but increased IL-17-producing CD4(+) T (Th17) cells in both spleen and draining lymph nodes of mice during the acute stage of collagen-induced arthritis (CIA) when compared with adjuvant-treated control mice. On adoptive transfer of in vitro expanded B10 cells, collagen-immunized mice showed a marked delay of arthritis onset with reduced severity of both clinical symptoms and joint damage, accompanied by a substantial reduction in the number of Th17 cells. To determine whether B10 cells directly inhibit the generation of Th17 cells in culture, naive CD4(+) T cells labeled with carboxyfluorescein succinimidyl ester (CFSE) were co-cultured with B10 cells. These B10 cells suppressed Th17 cell differentiation via the reduction of STAT3 phosphorylation and retinoid-related orphan receptor γt (RORγt) expression. Moreover, Th17 cells showed significantly decreased proliferation when co-cultured with B10 cells. Although adoptive transfer of Th17 cells triggered the development of collagen-induced arthritis in IL-17(-/-)DBA/1J mice, co-transfer of B10 cells with Th17 cells profoundly delayed the onset of arthritis. Thus, our findings suggest a novel regulatory role of B10 cells in arthritic progression via the suppression of Th17 cell generation. PMID:22538089

  6. Inhibition of miR-29c promotes proliferation, and inhibits apoptosis and differentiation in P19 embryonic carcinoma cells

    PubMed Central

    CHEN, BIN; SONG, GUIXIAN; LIU, MING; QIAN, LINGMEI; WANG, LIHUA; GU, HAITAO; SHEN, YAHUI

    2016-01-01

    In our previous study, the upregulation of microRNA (miR)-29c was identified in the mother of a fetus with a congenital heart defect. However, the functional and regulatory mechanisms of miR-29c in the development of the heart remain to be elucidated. In the present study, the role and mechanism of miR-29c inhibition in heart development were investigated in an embryonic carcinoma cell model. Inhibition of miR-29c promoted proliferation, and suppressed the apoptosis and differentiation of P19 cells. It was also demonstrated that Wingless-related MMTV integration site 4 (Wnt4) was a target of miR-29c, determined using bioinformatic analysis combined with luciferase assays. The inhibition of miR-29c stimulated the WNT4/β-catenin pathway, promoting proliferation of the P19 cells, but suppressing their differentiation into cardiomyocytes. Furthermore, the inhibition of miR-29c promoted the expression of B cell lymphoma-2 and inhibited cell apoptosis. These results demonstrate the significance of miR-29c in the process of cardiac development and suggest that miR-29c dysregulation may be associated with the occurrence of CHD. Thus, miR-29c may have therapeutic potential in the future. PMID:26848028

  7. Unexpected Regulatory Role of CCR9 in Regulatory T Cell Development

    PubMed Central

    Evans-Marin, Heather L.; Cao, Anthony T.; Yao, Suxia; Chen, Feidi; He, Chong; Liu, Han; Wu, Wei; Gonzalez, Maria G.; Dann, Sara M.; Cong, Yingzi

    2015-01-01

    T cells reactive to microbiota regulate the pathogenesis of inflammatory bowel disease (IBD). As T cell trafficking to intestines is regulated through interactions between highly specific chemokine-chemokine receptors, efforts have been made to develop intestine-specific immunosuppression based on blocking these key processes. CCR9, a gut-trophic chemokine receptor expressed by lymphocytes and dendritic cells, has been implicated in the regulation of IBD through mediating recruitment of T cells to inflamed sites. However, the role of CCR9 in inducing and sustaining inflammation in the context of IBD is poorly understood. In this study, we demonstrate that CCR9 deficiency in effector T cells and Tregs does not affect the development of colitis in a microbiota antigen-specific, T cell-mediated model. However, Treg cells express higher levels of CCR9 compared to those in effector T cells. Interestingly, CCR9 inhibits Treg cell development, in that CCR9-/- mice demonstrate a high level of Foxp3+ Tregs, and ligation of CCR9 by its ligand CCL25 inhibits Treg cell differentiation in vitro. Collectively, our data indicate that in addition to acting as a gut-homing molecule, CCR9 signaling shapes immune responses by inhibiting Treg cell development. PMID:26230654

  8. Mechanisms and treatment of allergic disease in the big picture of regulatory T cells.

    PubMed

    Akdis, Cezmi A; Akdis, Mübeccel

    2009-04-01

    Various populations of regulatory T (Treg) cells have been shown to play a central role in the maintenance of peripheral homeostasis and the establishment of controlled immune responses. Their identification as key regulators of immunologic processes in peripheral tolerance to allergens has opened an important era in the prevention and treatment of allergic diseases. Both naturally occurring CD4+CD25+ Treg cells and inducible populations of allergen-specific, IL-10-secreting Treg type 1 (T(R)1) cells inhibit allergen-specific effector cells in experimental models. Skewing of allergen-specific effector T cells to a regulatory phenotype appears to be a key event in the development of healthy immune response to allergens and successful outcome in allergen-specific immunotherapy. Forkhead box protein 3-positive CD4+CD25+ Treg cells and T(R)1 cells contribute to the control of allergen-specific immune responses in several major ways, which can be summarized as suppression of dendritic cells that support the generation of effector T cells; suppression of effector T(H)1, T(H)2, and T(H)17 cells; suppression of allergen-specific IgE and induction of IgG4; suppression of mast cells, basophils, and eosinophils; interaction with resident tissue cells and remodeling; and suppression of effector T-cell migration to tissues. Current strategies for drug development and allergen-specific immunotherapy exploit these observations, with the potential for preventive therapies and cure for allergic diseases. PMID:19348912

  9. B cells with regulatory properties in transplantation tolerance

    PubMed Central

    Durand, Justine; Chiffoleau, Elise

    2015-01-01

    Induction of tolerance remains a major goal in transplantation. Indeed, despite potent immunosuppression, chronic rejection is still a real problem in transplantation. The humoral response is an important mediator of chronic rejection, and numerous strategies have been developed to target either B cells or plasma cells. However, the use of anti-CD20 therapy has highlighted the beneficial role of subpopulation of B cells, termed regulatory B cells. These cells have been characterized mainly in mice models of auto-immune diseases but emerging literature suggests their role in graft tolerance in transplantation. Regulatory B cells seem to be induced following inflammation to restrain excessive response. Different phenotypes of regulatory B cells have been described and are functional at various differentiation steps from immature to plasma cells. These cells act by multiple mechanisms such as secretion of immuno-suppressive cytokines interleukin-10 (IL-10) or IL-35, cytotoxicity, expression of inhibitory receptors or by secretion of non-inflammatory antibodies. Better characterization of the development, phenotype and mode of action of these cells seems urgent to develop novel approaches to manipulate the different B cell subsets and the response to the graft in a clinical setting. PMID:26722647

  10. Toll-like receptor 2-mediated modulation of growth and functions of regulatory T cells by oral streptococci.

    PubMed

    Saeki, A; Segawa, T; Abe, T; Sugiyama, M; Arimoto, T; Hara, H; Hasebe, A; Ohtani, M; Tanizume, N; Ohuchi, M; Kataoka, H; Kawanami, M; Yokoyama, A; Shibata, K

    2013-08-01

    This study was designed to determine whether oral streptococci modulate the growth and functions of regulatory T cells. Heat-killed cells of wild-type strains of Streptococcus gordonii and Streptococcus mutans induced the Toll-like receptor 2 (TLR2) -mediated nuclear factor-κB (NF-κB) activation, but their lipoprotein-deficient strains did not. Stimulation with these streptococci resulted in a significant increase in the frequency of CD4(+) CD25(+) Foxp3(+) regulatory T cells in splenocytes derived from both TLR2(+/+) and TLR2(-/-) mice, but the level of increase in TLR2(+/+) splenocytes was stronger than that in TLR2(-/-) splenocytes. Both strains of S. gordonii enhanced the proliferation of CD4(+) CD25(+) Foxp3(+) regulatory T cells isolated from TLR2(+/+) mice at the same level as those from TLR2(-/-) mice in an interleukin-2-independent manner. However, wild-type and lipoprotein-deficient strains of both streptococci did not enhance the suppressive activity of the isolated regulatory T cells in vitro, but rather inhibited it. TLR ligands also inhibited the suppressive activity of the regulatory T cells. Inhibition of the suppressive activity was recovered by the addition of anti-IL-6 antibody. Pretreatment of antigen-presenting cells with the NF-κB inhibitor BAY11-7082 enhanced the suppressive activity of the regulatory T cells. These results suggested that interleukin-6 produced by antigen-presenting cells inhibits the suppressive activity of the regulatory T cells. Wild-type strain, but not lipoprotein-deficient strain, of S. gordonii reduced the frequency of CD4(+)  CD25(+)  Foxp3(+) regulatory T cells in the acute infection model, whereas both strains of S. gordonii increased it in the chronic infection model mice. Hence, this study suggests that oral streptococci are capable of modulating the growth and functions of regulatory T cells in vitro and in vivo. PMID:23413817

  11. Human mesenchymal stem cells elevate CD4+CD25+CD127low/- regulatory T cells of asthmatic patients via heme oxygenase-1.

    PubMed

    Li, Jian-guo; Zhuan-sun, Yong-xun; Wen, Bing; Wu, Hao; Huang, Feng-ting; Ghimire, Hridaya bibhu; Ran, Pi-xin

    2013-09-01

    Up-regulation of CD4+CD25+CD127low/- regulatory T cells (Tregs) is a new target in the treatment of asthma. Human bone marrow mesenchymal stem cells can up-regulate CD4+CD25+CD127low/- regulatory T cells in vitro, meanwhile, heme oxygenase-1 (HO-1) plays an important role in the development and maintenance of CD4+CD25+ regulatory T cells. However the mechanism has not yet been adequately understood. Hence, we wondered what effect of Heme Oxygenase-1 made on regulation of CD4+CD25+CD127low/- regulatory T cells mediated by mesenchymal stem cells. Peripheral blood mononuclear cells isolated from asthmatic patients and healthy controls were co-cultured with human bone marrow mesenchymal stem cells which were pretreated with Hemin (the revulsive of Heme Oxygenase-1), Protoporphyrin Ⅸ zinc (the inhibitor of Heme Oxygenase-1) and saline. The expression of Heme Oxygenase-1 in MSCs was enhanced by Hemin and inhibited by Protoporphyrin  zinc in vitro. Overexpression of Heme Oxygenase-1 elevated the proportion of CD4+CD25+CD127low/- regulatory T cells in CD4+ T cells, meanwhile, inhibition of Heme Oxygenase-1 decreased the proportion of CD4+CD25+CD127low/- regulatory T cells in CD4+ T cells as compared with mesenchymal stem cells alone. Taken together, these data demonstrated that Heme Oxygenase-1 contributed to the up-regulation of CD4+CD25+CD127low/- regulatory T cells mediated by mesenchymal stem cells in asthma.  PMID:23893806

  12. Leptin deficiency impairs maturation of dendritic cells and enhances induction of regulatory T and Th17 cells

    PubMed Central

    Moraes-Vieira, Pedro M.M.; Larocca, Rafael A.; Bassi, Enio J.; Peron, Jean Pierre S.; Andrade-Oliveira, Vinícius; Wasinski, Frederick; Araujo, Ronaldo; Thornley, Thomas; Quintana, Francisco J.; Basso, Alexandre S.; Strom, Terry B.; Câmara, Niels O.S.

    2016-01-01

    Leptin is an adipose-secreted hormone that plays an important role in both metabolism and immunity. Leptin has been shown to induce Th1-cell polarization and inhibit Th2-cell responses. Additionally, leptin induces Th17-cell responses, inhibits regulatory T (Treg) cells and modulates autoimmune diseases. Here, we investigated whether leptin mediates its activity on T cells by influencing dendritic cells (DCs) to promote Th17 and Treg-cell immune responses in mice. We observed that leptin deficiency (i) reduced the expression of DC maturation markers, (ii) decreased DC production of IL-12, TNF-α, and IL-6, (iii) increased DC production of TGF-β, and (iv) limited the capacity of DCs to induce syngeneic CD4+ T-cell proliferation. As a consequence of this unique phenotype, DCs generated under leptin-free conditions induced Treg or TH17 cells more efficiently than DCs generated in the presence of leptin. These data indicate important roles for leptin in DC homeostasis and the initiation and maintenance of inflammatory and regulatory immune responses by DCs. PMID:24271843

  13. Inhibition of mast cells by algae.

    PubMed

    Price, Joseph A; Sanny, Charles; Shevlin, Dennis

    2002-01-01

    There is a history of use of algae as foods and as food additives, or nutraceuticals. Although algae are a safe component of human foods and animal feeds, the effects of the algae other than as a source of protein are not clear. We examined the prevalence of an antiinflammatory activity in selected algae using, as an assay system, the inhibition of histamine release from mast cells. Methanolic extracts of eleven algae were examined for activity to inhibit the release of histamine from mast cells in vitro. This activity was found widely among the samples tested. The activities of these extracts were not uniformly stable in acid methanol. Selected extracts studied further did not separate with the use of size-exclusion filtration filters. LH-20 chromatography suggested at least two main elution areas of activity of the Chlorella extract. In summary, we saw wide phylogenetic dispersion of mast cell inhibition activity, suggesting that this antiinflammatory property is common in algae. This effect was apparently due to multiple activities within the algal extracts. PMID:12639395

  14. Garcinol inhibits tumour cell proliferation, angiogenesis, cell cycle progression and induces apoptosis via NF-κB inhibition in oral cancer.

    PubMed

    Aggarwal, Sadhna; Das, Satya N

    2016-06-01

    Garcinol, a polyisoprenylated benzophenone is extracted from the rind of the fruit of Garcinia indica, a plant found extensively in tropical regions. Its ability to inhibit tumour growth has been demonstrated in certain cancers. In this study, we evaluated the potential anti-tumour effects of garcinol on oral squamous cell carcinoma (OSCC) cells. Three OSCC cell lines (SCC-4, SCC-9 and SCC-25) were treated with garcinol for 48 h and its effect on growth and proliferation, clonogenic survival, cell cycle and apoptosis was studied by MTT, clonogenic assay, propidium iodide (PI) staining and annexin-V binding assay, respectively. The alteration in expression of NF-κB and COX-2 was studied by western blot analysis and that of VEGF by ELISA. Garcinol treatment significantly (p < 0.001) inhibited the growth and proliferation and colony formation of OSCC cells with a concomitant induction of apoptosis and cell cycle arrest. It did not show toxic effect on normal cells. It significantly (p < 0.05) reduced the expression of NK-κB and COX-2 expression in treated cells as compared to untreated controls besides inhibiting VEGF expression. It appears that garcinol exerts anti-proliferative, pro-apoptotic, cell-cycle regulatory and anti-angiogenic effects on oral cancer cells through inhibition of NF-κB and COX-2. Thus, garcinol may be developed as a potential chemopreventive and/or chemotherapeutic agent for treatment of oral squamous cell carcinoma. PMID:26662963

  15. Liver epithelial cells inhibit proliferation and invasiveness of hepatoma cells.

    PubMed

    Jeng, Kuo-Shyang; Jeng, Chi-Juei; Jeng, Wen-Juei; Sheen, I-Shyan; Li, Shih-Yun; Hung, Zih-Hang; Hsiau, Hsin-I; Yu, Ming-Che; Chang, Chiung-Fang

    2016-03-01

    Hepatocellular carcinoma (HCC) is a worldwide malignancy with poor prognosis. Liver progenitors or stem cells could be a potential therapy for HCC treatment since they migrate toward tumors. Rat liver epithelial (RLE) cells have both progenitor and stem cell-like properties. Therefore, our study elucidated the therapeutic effect of RLE cells in rat hepatoma cells. RLE cells were isolated from 10-day old rats and characterized for stem cell marker expression. RLE cells and rat hepatoma cells (H4-IIE-C3 cells) were co-cultured and divided into four groups with different ratios of RLE and hepatoma cells. Group A had only rat hepatoma cells as a control group. The ratios of rat hepatoma and RLE cells in group B, C and D were 5:1, 1:1 and 1:5, respectively. Effective inhibition of cell proliferation and migration was found in group D when compared to group A. There was a significant decrease in Bcl2 expression and increase in late apoptosis of rat hepatoma cells when adding more RLE cells. RLE cells reduced cell proliferation and migration of rat hepatoma cells. These results suggested that RLE cells could be used as a potential cell therapy. PMID:26647726

  16. Regulatory Insight into the European Human Pluripotent Stem Cell Registry

    PubMed Central

    Kurtz, Andreas; Stacey, Glyn; Kidane, Luam; Seriola, Anna; Stachelscheid, Harald; Veiga, Anna

    2014-01-01

    Abstract The European pluripotent stem cell registry aims at listing qualified pluripotent stem cell (PSC) lines that are available globally together with relevant information for each cell line. Specific emphasis is being put on documenting ethical procurement of the cells and providing evidence of pluripotency. The report discusses the tasks and challenges for a global PSC registry as an instrument to develop collaboration, to access cells from diverse resources and banks, and to implement standards, and as a means to follow up usage of cells and support adherence to regulatory and scientific standards and transparency for stakeholders. PMID:25457963

  17. Regulatory insight into the European human pluripotent stem cell registry.

    PubMed

    Kurtz, Andreas; Stacey, Glyn; Kidane, Luam; Seriola, Anna; Stachelscheid, Harald; Veiga, Anna

    2014-12-01

    The European pluripotent stem cell registry aims at listing qualified pluripotent stem cell (PSC) lines that are available globally together with relevant information for each cell line. Specific emphasis is being put on documenting ethical procurement of the cells and providing evidence of pluripotency. The report discusses the tasks and challenges for a global PSC registry as an instrument to develop collaboration, to access cells from diverse resources and banks, and to implement standards, and as a means to follow up usage of cells and support adherence to regulatory and scientific standards and transparency for stakeholders. PMID:25457963

  18. Movement of regulatory RNA between animal cells

    PubMed Central

    Jose, Antony M.

    2015-01-01

    Summary Recent studies suggest that RNA can move from one cell to another and regulate genes through specific base-pairing. Mechanisms that modify or select RNA for secretion from a cell are unclear. Secreted RNA can be stable enough to be detected in the extracellular environment and can enter the cytosol of distant cells to regulate genes. Mechanisms that import RNA into the cytosol of an animal cell can enable uptake of RNA from many sources including other organisms. This role of RNA is akin to that of steroid hormones, which cross cell membranes to regulate genes. The potential diagnostic use of RNA in human extracellular fluids has ignited interest in understanding mechanisms that enable the movement of RNA between animal cells. Genetic model systems will be essential to gain more confidence in proposed mechanisms of RNA transport and to connect an extracellular RNA with a specific biological function. Studies in the worm C. elegans and in other animals have begun to reveal parts of this novel mechanism of cell-to-cell communication. Here, I summarize the current state of this nascent field, highlight the many unknowns, and suggest future directions. PMID:26138457

  19. Reciprocity between Regulatory T Cells and Th17 Cells: Relevance to Polarized Immunity in Leprosy.

    PubMed

    Sadhu, Soumi; Khaitan, Binod Kumar; Joshi, Beenu; Sengupta, Utpal; Nautiyal, Arvind Kumar; Mitra, Dipendra Kumar

    2016-01-01

    T cell defect is a common feature in lepromatous or borderline lepromatous leprosy (LL/BL) patients in contrast to tuberculoid or borderline tuberculoid type (TT/BT) patients. Tuberculoid leprosy is characterized by strong Th1-type cell response with localized lesions whereas lepromatous leprosy is hallmarked by its selective Mycobacterium leprae specific T cell anergy leading to disseminated and progressive disease. FoxP3+ Regulatory T cells (Treg) which are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory diseases also dampen proinflammatory T cells that include T helper 17 (Th17) cells. This study is aimed at evaluating the role of Treg cells in influencing other effector T cells and its relationship with the cytokine polarized state in leprosy patients. Peripheral blood mononuclear cells from of BT/TT (n = 15) and BL/LL (n = 15) patients were stimulated with M. leprae antigen (WCL) in presence of golgi transport inhibitor monensin for FACS based intracellular cytokine estimation. The frequency of Treg cells showed >5-fold increase in BL/LL in comparison to BT/TT and healthy contacts. These cells produced suppressive cytokine, IL-10 in BL/LL as opposed to BT/TT (p = 0.0200) indicating their suppressive function. The frequency of Th17 cells (CD4, CD45RO, IL-17) was, however, higher in BT/TT. Significant negative correlation (r = -0.68, P = 0.03) was also found between IL-10 of Treg cells and IL-17+ T cells in BL/LL. Blocking IL-10/TGF-β restored the IL-17+ T cells in BL/LL patients. Simultaneously, presence of Th17 related cytokines (TGF-β, IL-6, IL-17 and IL-23) decreased the number of FoxP3+ Treg cells concomitantly increasing IL-17 producing CD4+ cells in lepromatous leprosy. Higher frequency of Programmed Death-1/PD-1+ Treg cells and its ligand, PDL-1 in antigen presenting cells (APCs) was found in BL/LL patients. Inhibition of this pathway led to rescue of IFN-γ and IL-17 producing T cells

  20. Reciprocity between Regulatory T Cells and Th17 Cells: Relevance to Polarized Immunity in Leprosy

    PubMed Central

    Sadhu, Soumi; Khaitan, Binod Kumar; Joshi, Beenu; Sengupta, Utpal; Nautiyal, Arvind Kumar; Mitra, Dipendra Kumar

    2016-01-01

    T cell defect is a common feature in lepromatous or borderline lepromatous leprosy (LL/BL) patients in contrast to tuberculoid or borderline tuberculoid type (TT/BT) patients. Tuberculoid leprosy is characterized by strong Th1-type cell response with localized lesions whereas lepromatous leprosy is hallmarked by its selective Mycobacterium leprae specific T cell anergy leading to disseminated and progressive disease. FoxP3+ Regulatory T cells (Treg) which are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory diseases also dampen proinflammatory T cells that include T helper 17 (Th17) cells. This study is aimed at evaluating the role of Treg cells in influencing other effector T cells and its relationship with the cytokine polarized state in leprosy patients. Peripheral blood mononuclear cells from of BT/TT (n = 15) and BL/LL (n = 15) patients were stimulated with M. leprae antigen (WCL) in presence of golgi transport inhibitor monensin for FACS based intracellular cytokine estimation. The frequency of Treg cells showed >5-fold increase in BL/LL in comparison to BT/TT and healthy contacts. These cells produced suppressive cytokine, IL-10 in BL/LL as opposed to BT/TT (p = 0.0200) indicating their suppressive function. The frequency of Th17 cells (CD4, CD45RO, IL-17) was, however, higher in BT/TT. Significant negative correlation (r = -0.68, P = 0.03) was also found between IL-10 of Treg cells and IL-17+ T cells in BL/LL. Blocking IL-10/TGF-β restored the IL-17+ T cells in BL/LL patients. Simultaneously, presence of Th17 related cytokines (TGF-β, IL-6, IL-17 and IL-23) decreased the number of FoxP3+ Treg cells concomitantly increasing IL-17 producing CD4+ cells in lepromatous leprosy. Higher frequency of Programmed Death-1/PD-1+ Treg cells and its ligand, PDL-1 in antigen presenting cells (APCs) was found in BL/LL patients. Inhibition of this pathway led to rescue of IFN-γ and IL-17 producing T cells

  1. Escape from suppression: tumor-specific effector cells outcompete regulatory T cells following stem-cell transplantation

    PubMed Central

    Mirmonsef, Paria; Tan, Gladys; Zhou, Gang; Morino, Tricia; Noonan, Kimberly; Borrello, Ivan

    2008-01-01

    Immune reconstitution of autologous hematopoietic stem-cell transplant recipients with the progeny of mature T cells in the graft leads to profound changes in the emerging functional T-cell repertoire. In the steady state, the host is frequently tolerant to tumor antigens, reflecting dominant suppression of naive and effector T cells by regulatory T cells (Tregs). We examined the relative frequency and function of these 3 components within the tumor-specific T-cell compartment during immune reconstitution. Grafts from tumor-bearing donors exerted a significant antitumor effect in irradiated, syngeneic tumor-bearing recipients. This was associated with dramatic clonal expansion and interferon-γ (IFNγ) production by previously tolerant tumor-specific T cells. While donor-derived Tregs expanded in recipients, they did not inhibit the antigen-driven expansion of effector T cells in the early posttransplantation period. Indeed, the repopulation of tumor-specific effector T cells significantly exceeded that of Tregs, the expansion of which was limited by IL-2 availability. Although the intrinsic suppressive capacity of Tregs remained intact, their diminished frequency was insufficient to suppress effector cell function. These findings provide an explanation for the reversal of tolerance leading to tumor rejection in transplant recipients and likely contribute to the efficacy of adoptive T-cell therapies in lymphopenic hosts. PMID:18063750

  2. Comparison of circulating and intratumoral regulatory T cells in patients with renal cell carcinoma.

    PubMed

    Asma, Gati; Amal, Gorrab; Raja, Marrakchi; Amine, Derouiche; Mohammed, Chebil; Amel, Ben Ammar Elgaaied

    2015-05-01

    The clear evidence that tumor-infiltrating lymphocytes (TIL) exists in the tumor microenvironment raises the question why renal cell carcinoma (RCC) progresses. Numerous studies support the implication of CD4(+)CD25(high) regulatory T (Treg) cells in RCC development. We aimed in this study to characterize the phenotype and function of circulating and intratumoral Treg cells of RCC patient in order to evaluate their implication in the inhibition of the local antitumor immune response. Our results demonstrate that the proportion of Treg in TIL was, in average, similar to that found in circulating CD4(+) T cells of patients or healthy donors. However, intratumoral Treg exhibit a marked different phenotype when compared with the autologous circulating Treg. A higher CD25 mean level, HLA-DR, Fas, and GITR, and a lower CD45RA expression were observed in intratumoral Treg, suggesting therefore that these cells are effector in the tumor microenvironment. Additionally, intratumoral Treg showed a higher inhibitory function on autologous CD4(+)CD25(-) T cells when compared with circulating Treg that may be explained by an overexpression of FoxP3 transcription factor. These findings suggest that intratumoral Treg could be major actors in the impairment of local antitumor immune response for RCC patients. PMID:25563193

  3. De novo fatty acid synthesis controls the fate between regulatory T and T helper 17 cells.

    PubMed

    Berod, Luciana; Friedrich, Christin; Nandan, Amrita; Freitag, Jenny; Hagemann, Stefanie; Harmrolfs, Kirsten; Sandouk, Aline; Hesse, Christina; Castro, Carla N; Bähre, Heike; Tschirner, Sarah K; Gorinski, Nataliya; Gohmert, Melanie; Mayer, Christian T; Huehn, Jochen; Ponimaskin, Evgeni; Abraham, Wolf-Rainer; Müller, Rolf; Lochner, Matthias; Sparwasser, Tim

    2014-11-01

    Interleukin-17 (IL-17)-secreting T cells of the T helper 17 (TH17) lineage play a pathogenic role in multiple inflammatory and autoimmune conditions and thus represent a highly attractive target for therapeutic intervention. We report that inhibition of acetyl-CoA carboxylase 1 (ACC1) restrains the formation of human and mouse TH17 cells and promotes the development of anti-inflammatory Foxp3(+) regulatory T (Treg) cells. We show that TH17 cells, but not Treg cells, depend on ACC1-mediated de novo fatty acid synthesis and the underlying glycolytic-lipogenic metabolic pathway for their development. Although TH17 cells use this pathway to produce phospholipids for cellular membranes, Treg cells readily take up exogenous fatty acids for this purpose. Notably, pharmacologic inhibition or T cell-specific deletion of ACC1 not only blocks de novo fatty acid synthesis but also interferes with the metabolic flux of glucose-derived carbon via glycolysis and the tricarboxylic acid cycle. In vivo, treatment with the ACC-specific inhibitor soraphen A or T cell-specific deletion of ACC1 in mice attenuates TH17 cell-mediated autoimmune disease. Our results indicate fundamental differences between TH17 cells and Treg cells regarding their dependency on ACC1-mediated de novo fatty acid synthesis, which might be exploited as a new strategy for metabolic immune modulation of TH17 cell-mediated inflammatory diseases. PMID:25282359

  4. Moving to tolerance: Clinical Application of T regulatory cells

    PubMed Central

    McMurchy, Alicia N.; Bushell, Andrew; Levings, Megan K.; Wood, Kathryn J.

    2013-01-01

    Decreasing the incidence of chronic rejection and reducing the need for life-long immunosuppression remain important goals in clinical transplantation. In this article, we will review how regulatory T cells (Treg) came to be recognized as an attractive way to prevent or treat allograft rejection, the ways in which Treg can be manipulated or expanded in vivo, and the potential of in vitro expanded/generated Treg for cellular therapy. We will describe the first regulatory T cell therapies that have been or are in the process of being conducted in the clinic as well as the safety concerns of such therapies and how outcomes may be measured. PMID:21620722

  5. Stat3 inhibition in neural lineage cells.

    PubMed

    Chiba, Tomohiro; Mack, Laura; Delis, Natalia; Brill, Boris; Groner, Bernd

    2012-06-01

    Abstract Deregulation of signal transducer and activator of transcription 3 (Stat3) is attracting attentions in neurological disorders of elderly populations, e.g., Stat3 is inactivated in hippocampal neurons of Alzheimer's disease (AD) brains, whereas it is often constitutively activated in glioblastoma multiforme (GBM), correlating with poor prognosis. Stat3-inhibiting drugs have been intensively developed for chemotherapy based on the fact that GBM, in many cases, are "addicted" to Stat3 activation. Stat3 inhibitors, however, potentially have unfavorable side effects on postmitotic neurons, normal permanent residents in the central nervous system. It is, therefore, of great importance to address detailed cellular responses of neural lineage cells including normal neurons, astrocytes, and neuronal/glial cancer cell lines to several classes of Stat3 inhibitors focusing on their effective concentrations. Here, we picked up five human and mouse cancer cell lines (Neuro-2a and SH-SY5Y neuroblastoma cell lines and Tu-9648, U-87MG, and U-373MG glioblastoma cell lines) and treated with various Stat3 inhibitors. Among them, Stattic, FLLL31, and resveratrol potently suppressed P-Stat3 and cell viability in all the tested cell lines. Stat3 knockdown or expression of dominant-negative Stat3 further sensitized cells to the inhibitors. Expression of familial AD-related mutant amyloid precursor protein sensitized neuronal cells, not glial cells, to Stat3 inhibitors by reducing P-Stat3 levels. Primary neurons and astrocytes also responded to Stat3 inhibitors with similar sensitivities to those observed in cancer cell lines. Thus, Stat3 inhibitors should be carefully targeted to GBM cells to avoid potential neurotoxicity leading to AD-like neuropsychiatric dysfunctions. PMID:25436682

  6. VEGFA/VEGFR2-targeted therapies prevent the VEGFA-induced proliferation of regulatory T cells in cancer

    PubMed Central

    Terme, Magali; Tartour, Eric; Taieb, Julien

    2013-01-01

    Some of the anti-angiogenic agents currently used to treat solid malignancies have effects on tumor endothelial cells as well as on immune cells. We have recently demonstrated that targeting the vascular endothelial growth factor A (VEGFA)/VEGF receptor 2 (VEGFR2) signaling pathway reduces the proportion of regulatory T cells (Treg) in a mouse model of colorectal cancer (CRC) and in metastatic CRC patients as it inhibits tumor-induced Treg proliferation. PMID:24083078

  7. Subversion of cell cycle regulatory mechanisms by HIV

    PubMed Central

    Rice, Andrew P.; Kimata, Jason T.

    2015-01-01

    To establish a productive infection, HIV-1 must counteract cellular innate immune mechanisms and redirect cellular process towards viral replication. Recent studies have discovered that HIV-1 and other primate immunodeficiency viruses subvert cell cycle regulatory mechanisms to achieve these ends. The viral Vpr and Vpx proteins target cell cycle controls to counter innate immunity. The cell cycle-related protein Cyclin L2 is also utilized to counter innate immunity. The viral Tat protein utilizes Cyclin T1 to activated proviral transcription, and regulation of Cyclin T1 levels in CD4+ T cells has important consequences for viral replication and latency. This review will summarize this emerging evidence that primate immunodeficiency viruses subvert cell cycle regulatory mechanisms to enhance replication. PMID:26067601

  8. Regulatory volume decrease in perfused proximal nephron: evidence for a dumping of cell K+.

    PubMed

    Kirk, K L; DiBona, D R; Schafer, J A

    1987-05-01

    We utilized the microscopic and morphometric procedures described in the preceding paper to examine the role of a swelling-activated dumping of K-salt in the reversal of hyposmotic cell swelling in the perfused proximal nephron. The rate of the regulatory volume decrease that follows cell swelling in dilute solutions was reduced by two maneuvers that attenuate the K+ chemical potential difference across the basolateral membrane; inhibiting the Na+-K+ pump (e.g., with ouabain) and raising the peritubular K+ concentration. The rate of the regulatory volume decrease was also inhibited by peritubular quinine, which blocks K channels and volume regulation for a number of mammalian cells. Additionally, exposure to hyposmotic solutions resulted in a sustained and quinine-sensitive increase in the apparent permeability of the basolateral membrane to K+ salt, which was monitored qualitatively as the rate of cell volume change that was induced by a perturbation in the peritubular K+ concentration. The simplest interpretation of these results is that the reversal of hyposmotic cell swelling in the proximal nephron is referable at least in part to a swelling-activated loss of K-salt and water from the cells. PMID:2437806

  9. An essential regulatory role for macrophage migration inhibitory factor in T-cell activation.

    PubMed Central

    Bacher, M; Metz, C N; Calandra, T; Mayer, K; Chesney, J; Lohoff, M; Gemsa, D; Donnelly, T; Bucala, R

    1996-01-01

    The protein known as macrophage migration inhibitory factor (MIF) was one of the first cytokines to be discovered and was described 30 years ago to be a T-cell-derived factor that inhibited the random migration of macrophages in vitro. A much broader role for MIF has emerged recently as a result of studies that have demonstrated it to be released from the anterior pituitary gland in vivo. MIF also is the first protein that has been identified to be secreted from monocytes/macrophages upon glucocorticoid stimulation. Once released, MIF acts to "override" or counter-regulate the suppressive effects of glucocorticoids on macrophage cytokine production. We report herein that MIF plays an important regulatory role in the activation of T cells induced by mitogenic or antigenic stimuli. Activated T cells produce MIF and neutralizing anti-MIF antibodies inhibit T-cell proliferation and interleukin 2 production in vitro, and suppress antigen-driven T-cell activation and antibody production in vivo. T cells also release MIF in response to glucocorticoid stimulation and MIF acts to override glucocorticoid inhibition of T-cell proliferation and interleukin 2 and interferon gamma production. These studies indicate that MIF acts in concert with glucocorticoids to control T-cell activation and assign a previously unsuspected but critical role for MIF in antigen-specific immune responses. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8755565

  10. Defective regulatory B-cell compartment in patients with immune thrombocytopenia

    PubMed Central

    Li, Xiaojuan; Zhong, Hui; Bao, Weili; Boulad, Nayla; Evangelista, Jessie; Haider, Muhammad Anis; Bussel, James

    2012-01-01

    B lymphocytes producing antiplatelet autoantibodies play a major role in autoimmune thrombocytopenia (ITP). However, certain B cells, including the human CD19+CD24hiCD38hi subpopulation, possess regulatory functions mediated partly by IL-10. In a cohort of chronic ITP patients with low platelet counts who consisted of patients off treatment, we found a lower frequency of CD19+CD24hiCD38hi in the peripheral compartment of nonsplenectomized patients (P = .03). IL-10 expression after activation was decreased in all ITP circulating CD19+ subpopulations (P < .03), and inhibition of monocyte TNF-α expression by activated B cells was reduced in patients with platelet numbers of < 50 × 109 cells/L (P = .001), indicating that regulatory B cells of patients with ITP are functionally impaired in their ability to dampen monocyte activation. Interestingly, in nonsplenectomized patients whose platelet counts were elevated after treatment with thrombopoietic agents, the frequency of CD19+CD24hiCD38hi B cells was increased compared with those before treatment (P = .02). Altogether, these data indicate a compromised regulatory B-cell com-partment as an additional defect in immune regulation in patients with chronic ITP that may be restored in responders to thrombopoietic treatment. PMID:22859611

  11. The role of regulatory B cells (Bregs) in the Tregs-amplifying effect of Sirolimus.

    PubMed

    Song, Jiyong; Xiao, Li; Du, Guosheng; Gao, Yu; Chen, Wen; Yang, Shaozhen; Fan, Wenmei; Shi, Bingyi

    2016-09-01

    Sirolimus can significantly amplify regulatory T cells (Tregs) in vivo and in vitro, but the specific mechanism of this has not been well documented. The role of regulatory B cells (Bregs) in the Tregs-amplifying effect of Sirolimus was investigated in peripheral blood mononuclear cells (PBMCs) in vitro in this study. The results showed that the percentages of both CD19+CD24+CD38+TGF-β1+ Bregs and CD19+CD24+CD38+IL-10+ Bregs to B cells were elevated by Sirolimus in PBMCs including B cells. Sirolimus significantly enhances the cytokine production of transforming growth factor-β1 (TGF-β1) and interleukin-10 (IL-10) in PBMCs with B cells, and the enhancement significantly decreased in PBMCs without B cells. The percentage of CD4+CD25+Foxp3+ Tregs to T cells was also elevated by Sirolimus in PBMCs including B cells. The elevation of Tregs percentage decreased in PBMCs without B cells and recovered when additional TGF-β1 and IL-10 were added. The amplification of Tregs by Sirolimus was partially inhibited when either TGF-β1 or IL-10 was neutralized, and it even disappeared when these two cytokines were both neutralized. These results indicate that Sirolimus can amplify Bregs and Tregs in PBMCs in vitro, and Bregs may be the why Sirolimus amplifies Tregs. PMID:27258186

  12. Monoterpenes inhibit cell growth, cell cycle progression, and cyclin D1 gene expression in human breast cancer cell lines.

    PubMed

    Bardon, S; Picard, K; Martel, P

    1998-01-01

    Monoterpenes are found in the essential oils of many commonly consumed fruits and vegetables. These compounds have been shown to exert chemopreventive and chemotherapeutic activities in mammary tumor models and represent a new class of breast cancer therapeutic agents. In this study, we investigated the effects of limonene and limonene-related monoterpenes, perillyl alcohol and perillic acid, on cell growth, cell cycle progression, and expression of cyclin D1 cell cycle-regulatory gene in T-47D, MCF-7, and MDA-MB-231 breast cancer cell lines. Our results revealed that limonene-related monoterpenes caused a dose-dependent inhibition of cell proliferation. Of the three monoterpenes tested, perillyl alcohol was the most potent and limonene was the least potent inhibitor of cell growth. The enantiomeric composition of limonene and perillyl alcohol did not interfere with their effect on cell growth. Sensitivity of breast cancer cell lines to monoterpenes was in the following order: T-47D > MCF-7 > MDA-MB-231. Growth inhibition induced by perillyl alcohol and perillic acid was associated with a fall in the proportion of cells in the S phase and an accumulation of cells in the G1 phase of the cell cycle. Finally, we showed that the effects of limonene-related monoterpenes on cell proliferation and cell cycle progression were preceded by a decrease in cyclin D1 mRNA levels. PMID:9824849

  13. Hepatitis C virus core protein inhibits interferon production by a human plasmacytoid dendritic cell line and dysregulates interferon regulatory factor-7 and signal transducer and activator of transcription (STAT) 1 protein expression.

    PubMed

    Stone, Amy E L; Mitchell, Angela; Brownell, Jessica; Miklin, Daniel J; Golden-Mason, Lucy; Polyak, Stephen J; Gale, Michael J; Rosen, Hugo R

    2014-01-01

    Plasmacytoid Dendritic Cells (pDCs) represent a key immune cell population in the defense against viruses. pDCs detect viral pathogen associated molecular patterns (PAMPs) through pattern recognition receptors (PRR). PRR/PAMP interactions trigger signaling events that induce interferon (IFN) production to initiate local and systemic responses. pDCs produce Type I and Type III (IFNL) IFNs in response to HCV RNA. Extracellular HCV core protein (Core) is found in the circulation in chronic infection. This study defined how Core modulates PRR signaling in pDCs. Type I and III IFN expression and production following exposure to recombinant Core or β-galactosiade was assessed in human GEN2.2 cells, a pDC cell line. Core suppressed type I and III IFN production in response to TLR agonists and the HCV PAMP agonist of RIG-I. Core suppression of IFN induction was linked with decreased IRF-7 protein levels and increased non-phosphorylated STAT1 protein. Circulating Core protein interferes with PRR signaling by pDCs to suppress IFN production. Strategies to define and target Core effects on pDCs may serve to enhance IFN production and antiviral actions against HCV. PMID:24788809

  14. Levels of Interleukin-35 and Its Relationship with Regulatory T-Cells in Chronic Hepatitis B Patients

    PubMed Central

    Shi, Yin-yue; Dai, Ming-jia; Wu, Gui-ping; Zhou, Pei-pei; Fang, Yuan

    2015-01-01

    Abstract Interleukin-35 is a novel inhibition cytokine secreted by CD4+CD25+ regulatory T-cells (Treg) in murine. However, it is disputed whether IL-35 could be secreted by Treg cells in humans. In this study, the levels of IL-35 were detected, and its relationship with regulatory T-cells in chronic hepatitis B (CHB) patients was investigated. It was shown that the levels of IL-35 in CHB patients were higher than those in normal controls, and the levels increased gradually, accompanied with the severe liver inflammation and necrosis and poor synthesis function. Treg cells may secrete IL-35, whose levels would become higher, accompanied by a longer activated time. Thus, IL-35 as a cytokine secreted by Treg cells may accelerate liver inflammation and necrosis, and inhibit the synthesis function. PMID:25494369

  15. Culture at a Higher Temperature Mildly Inhibits Cancer Cell Growth but Enhances Chemotherapeutic Effects by Inhibiting Cell-Cell Collaboration

    PubMed Central

    Zhu, Shengming; Wang, Jiangang; Xie, Bingkun; Luo, Zhiguo; Lin, Xiukun; Liao, D. Joshua

    2015-01-01

    Acute febrile infections have historically been used to treat cancer. To explore the underlying mechanism, we studied chronic effects of fever on cancer cell growth and chemotherapeutic efficacy in cell culture. We found that culturing cancer cells at 39°C mildly inhibited cell growth by arresting the cells at the G1 phase of the cell cycle. When cells were seeded in culture dishes at a lower density, e.g. about 1000–2000 cells per 35-mm dish, the growth inhibition was much greater, manifested as many fewer cell colonies in the 39°C dishes, compared with the results at a higher density seeding, e.g. 20,000 cells per dish, suggesting that cell-cell collaboration as the Allee effect in cell culture is inhibited at 39°C. Withdrawal of cells from serum enhanced the G1 arrest at 39°C and, for some cell lines such as A549 lung cancer cells, serum replenishment failed to quickly drive the cells from the G1 into the S and G2-M phases. Therapeutic effects of several chemotherapeutic agents, including clove bud extracts, on several cancer cell lines were more potent at 39°C than at 37°C, especially when the cells were seeded at a low density. For some cell lines and some agents, this enhancement is long-lasting, i.e. continuing after the cessation of the treatment. Collectively these results suggest that hyperthermia may inhibit cancer cell growth by G1 arrest and by inhibition of cell-cell collaboration, and may enhance the efficacy of several chemotherapeutic agents, an effect which may persist beyond the termination of chemotherapy. PMID:26495849

  16. Culture at a Higher Temperature Mildly Inhibits Cancer Cell Growth but Enhances Chemotherapeutic Effects by Inhibiting Cell-Cell Collaboration.

    PubMed

    Zhu, Shengming; Wang, Jiangang; Xie, Bingkun; Luo, Zhiguo; Lin, Xiukun; Liao, D Joshua

    2015-01-01

    Acute febrile infections have historically been used to treat cancer. To explore the underlying mechanism, we studied chronic effects of fever on cancer cell growth and chemotherapeutic efficacy in cell culture. We found that culturing cancer cells at 39°C mildly inhibited cell growth by arresting the cells at the G1 phase of the cell cycle. When cells were seeded in culture dishes at a lower density, e.g. about 1000-2000 cells per 35-mm dish, the growth inhibition was much greater, manifested as many fewer cell colonies in the 39°C dishes, compared with the results at a higher density seeding, e.g. 20,000 cells per dish, suggesting that cell-cell collaboration as the Allee effect in cell culture is inhibited at 39°C. Withdrawal of cells from serum enhanced the G1 arrest at 39°C and, for some cell lines such as A549 lung cancer cells, serum replenishment failed to quickly drive the cells from the G1 into the S and G2-M phases. Therapeutic effects of several chemotherapeutic agents, including clove bud extracts, on several cancer cell lines were more potent at 39°C than at 37°C, especially when the cells were seeded at a low density. For some cell lines and some agents, this enhancement is long-lasting, i.e. continuing after the cessation of the treatment. Collectively these results suggest that hyperthermia may inhibit cancer cell growth by G1 arrest and by inhibition of cell-cell collaboration, and may enhance the efficacy of several chemotherapeutic agents, an effect which may persist beyond the termination of chemotherapy. PMID:26495849

  17. FOXP3+ regulatory T cells in the human immune system.

    PubMed

    Sakaguchi, Shimon; Miyara, Makoto; Costantino, Cristina M; Hafler, David A

    2010-07-01

    Forkhead box P3 (FOXP3)(+) regulatory T (T(Reg)) cells are potent mediators of dominant self tolerance in the periphery. But confusion as to the identity, stability and suppressive function of human T(Reg) cells has, to date, impeded the general therapeutic use of these cells. Recent studies have suggested that human T(Reg) cells are functionally and phenotypically diverse. Here we discuss recent findings regarding human T(Reg) cells, including the ontogeny and development of T(Reg) cell subsets that have naive or memory phenotypes, the unique mechanisms of suppression mediated by T(Reg) cell subsets and factors that regulate T(Reg) cell lineage commitment. We discuss future studies that are needed for the successful therapeutic use of human T(Reg) cells. PMID:20559327

  18. The interplay of effector and regulatory T cells in cancer.

    PubMed

    Roychoudhuri, Rahul; Eil, Robert L; Restifo, Nicholas P

    2015-04-01

    Regulatory T (Treg) cells suppress effector T (Teff) cells and prevent immune-mediated rejection of cancer. Much less appreciated are mechanisms by which Teff cells antagonize Treg cells. Herein, we consider how complex reciprocal interactions between Teff and Treg cells shape their population dynamics within tumors. Under states of tolerance, including during tumor escape, suppressed Teff cells support Treg cell populations through antigen-dependent provision of interleukin (IL)-2. During immune activation, Teff cells can lose this supportive capacity and directly antagonize Treg cell populations to neutralize their immunosuppressive function. While this latter state is rarely achieved spontaneously within tumors, we propose that therapeutic induction of immune activation has the potential to stably disrupt immunosuppressive population states resulting in durable cancer regression. PMID:25728990

  19. Metabolic Regulation of Regulatory T Cell Development and Function

    PubMed Central

    Coe, David John; Kishore, Madhav; Marelli-Berg, Federica

    2014-01-01

    It is now well established that the effector T cell (Teff) response is regulated by a series of metabolic switches. Quiescent T cells predominantly require adenosine triphosphate-generating processes, whereas proliferating Teff require high metabolic flux through growth-promoting pathways, such as glycolysis. Pathways that control metabolism and immune cell function are intimately linked, and changes in cell metabolism at both the cell and system levels have been shown to enhance or suppress specific T cell effector functions. Furthermore, functionally distinct T cell subsets require distinct energetic and biosynthetic pathways to support their specific functional needs. In particular, naturally occurring regulatory T cells (Treg) are characterized by a unique metabolic signature distinct to that of conventional Teff cells. We here briefly review the signaling pathways that control Treg metabolism and how this metabolic phenotype integrates their differentiation and function. Ultimately, these metabolic features may provide new opportunities for the therapeutic modulation of unwanted immune responses. PMID:25477880

  20. Generation and identification of tumor-evoked regulatory B cells

    PubMed Central

    Biragyn, Arya; Lee-Chang, Catalina; Bodogai, Monica

    2014-01-01

    The involvement of Bregs in cancer remains poorly understood despite their well-documented regulation of responses to the self and protection from harmful autoimmunity. We recently discovered a unique regulatory B cell subset evoked by breast cancer to mediate protection of metastasizing cancer cells. These results together with the wealth of findings of the last 40 years on B cells in tumorigenesis suggest the existence of additional cancer Bregs modulating anticancer responses. To facilitate the search for them, here we provide our detailed protocol for the characterization and generation of tumor-evoked regulatory B cells. Wherever applicable, we also discuss nuances and uniqueness of a Breg study in cancer to warn potential pitfalls. PMID:25015287

  1. Enhanced immunoregulation of mesenchymal stem cells by IL-10-producing type 1 regulatory T cells in collagen-induced arthritis

    PubMed Central

    Lim, Jung-Yeon; Im, Keon-Il; Lee, Eun-Sol; Kim, Nayoun; Nam, Young-Sun; Jeon, Young-Woo; Cho, Seok-Goo

    2016-01-01

    Mesenchymal stem cells (MSCs) possess immunomodulatory properties and have potential, however, there have been conflicting reports regarding their effects in rheumatoid arthritis (RA), which causes inflammation and destruction of the joints. Through a comparative analysis of regulatory T (Treg) and IL-10-producing type 1 regulatory T (Tr1) cells, we hypothesized that Tr1 cells enhance the immunoregulatory functions of MSCs, and that a combinatorial approach to cell therapy may exert synergistic immunomodulatory effects in an experimental animal model of rheumatoid arthritis (RA). A combination of MSCs and Tr1 cells prevented the development of destructive arthritis compared to single cell therapy. These therapeutic effects were associated with an increase in type II collagen (CII)-specific CD4+CD25+Foxp3+ Treg cells and inhibition of CII-specific CD4+IL-17+ T cells. We observed that Tr1 cells produce high levels of IL-10-dependent interferon (IFN)-β, which induces toll-like receptor (TLR) 3 expression in MSCs. Moreover, induction of indoleamine 2,3-dioxygenase (IDO) by TLR3 involved an autocrine IFN-β that was dependent on STAT1 signaling. Furthermore, we observed that production of IFN-β and IL-10 in Tr1 cells synergistically induces IDO in MSCs through the STAT1 pathway. These findings suggest co-administration of MSCs and Tr1 cells to be a novel therapeutic modality for clinical autoimmune diseases. PMID:27246365

  2. Enhanced immunoregulation of mesenchymal stem cells by IL-10-producing type 1 regulatory T cells in collagen-induced arthritis.

    PubMed

    Lim, Jung-Yeon; Im, Keon-Il; Lee, Eun-Sol; Kim, Nayoun; Nam, Young-Sun; Jeon, Young-Woo; Cho, Seok-Goo

    2016-01-01

    Mesenchymal stem cells (MSCs) possess immunomodulatory properties and have potential, however, there have been conflicting reports regarding their effects in rheumatoid arthritis (RA), which causes inflammation and destruction of the joints. Through a comparative analysis of regulatory T (Treg) and IL-10-producing type 1 regulatory T (Tr1) cells, we hypothesized that Tr1 cells enhance the immunoregulatory functions of MSCs, and that a combinatorial approach to cell therapy may exert synergistic immunomodulatory effects in an experimental animal model of rheumatoid arthritis (RA). A combination of MSCs and Tr1 cells prevented the development of destructive arthritis compared to single cell therapy. These therapeutic effects were associated with an increase in type II collagen (CII)-specific CD4+CD25+Foxp3+ Treg cells and inhibition of CII-specific CD4+IL-17+ T cells. We observed that Tr1 cells produce high levels of IL-10-dependent interferon (IFN)-β, which induces toll-like receptor (TLR) 3 expression in MSCs. Moreover, induction of indoleamine 2,3-dioxygenase (IDO) by TLR3 involved an autocrine IFN-β that was dependent on STAT1 signaling. Furthermore, we observed that production of IFN-β and IL-10 in Tr1 cells synergistically induces IDO in MSCs through the STAT1 pathway. These findings suggest co-administration of MSCs and Tr1 cells to be a novel therapeutic modality for clinical autoimmune diseases. PMID:27246365

  3. Inflammatory regulatory T cells in the microenvironments of ulcerative colitis and colon carcinoma.

    PubMed

    Kryczek, Ilona; Wang, Lin; Wu, Ke; Li, Wei; Zhao, Ende; Cui, Tracy; Wei, Shuang; Liu, Yan; Wang, Yin; Vatan, Linda; Szeliga, Wojciech; Greenson, Joel K; Roliński, Jacek; Zgodzinski, Witold; Huang, Emina; Tao, Kaixiong; Wang, Guobin; Zou, Weiping

    2016-08-01

    Foxp3(+)CD4(+) regulatory T (Treg) cells are thought to express negligible levels of effector cytokines, and inhibit immune responses and inflammation. Here, we have identified a population of IL-8(+)Foxp3(+)CD4(+) T cells in human peripheral blood, which is selectively increased in the microenvironments of ulcerative colitis and colon carcinoma. Phenotypically, this population is minimally overlapping with IL-17(+)Foxp3(+)CD4(+) T cells, and is different from IL-8(-)Foxp3(+)CD4(+) T cells in the same microenvironment. 40-60% of IL-8(+)Foxp3(+)CD4(+) T cells exhibit naive phenotype and express CD127, whereas IL-8(-)Foxp3(+)CD4(+) cells are basically memory T cells and express minimal CD127. The levels of CXCR5 expression are higher in IL-8(+)Foxp3(+) cells than in IL-8(-)Foxp3(+) cells. IL-2 and TGFβ induce IL-8(+)Foxp3(+) T cells. Exogenous Foxp3 expression promotes IL-8(+)Foxp3(+) T cells and inhibits effector cytokine IFNγ and IL-2 expression. Furthermore, Foxp3 binds to IL-8 proximal promoter and increases its activity. Functionally, IL-8(+)Foxp3(+) T cells inhibit T cell proliferation and effector cytokine production, but stimulate inflammatory cytokine production in the colon tissues, and promote neutrophil trafficking through IL-8. Thus, IL-8(+)Foxp3(+) cells may be an "inflammatory" Treg subset, and possess inflammatory and immunosuppressive dual biological activities. Given their dual roles and localization, these cells may be in a unique position to support tumor initiation and development in human chronic inflammatory environment. PMID:27622054

  4. SIRT1 controls cell proliferation by regulating contact inhibition.

    PubMed

    Cho, Elizabeth H; Dai, Yan

    2016-09-16

    Contact inhibition keeps cell proliferation in check and serves as a built-in protection against cancer development by arresting cell division upon cell-cell contact. Yet the complete mechanism behind this anti-cancer process remains largely unclear. Here we present SIRT1 as a novel regulator of contact inhibition. SIRT1 performs a wide variety of functions in biological processes, but its involvement in contact inhibition has not been explored to date. We used NIH3T3 cells, which are sensitive to contact inhibition, and H460 and DU145 cancer cells, which lack contact inhibition, to investigate the relationship between SIRT1 and contact inhibition. We show that SIRT1 overexpression in NIH3T3 cells overcomes contact inhibition while SIRT1 knockdown in cancer cells restores their lost contact inhibition. Moreover, we demonstrate that p27 protein expression is controlled by SIRT1 in contact inhibition. Overall, our findings underline the critical role of SIRT1 in contact inhibition and suggest SIRT1 inhibition as a potential strategy to suppress cancer cell growth by restoring contact inhibition. PMID:27514448

  5. [Regulatory T cells in chronic obstructive pulmonary disease].

    PubMed

    Limón-Camacho, Leonardo; Solleiro-Villavicencio, Helena; Pupko-Sissa, Ilana; Lascurain, Ricardo; Vargas-Rojas, María Inés

    2013-01-01

    Exposition to tobacco smoke has been established as the main risk factor to develop chronic obstructive pulmonary disease (COPD), by inducing inflammation of the airways. Several cell populations participate in this inflammatory process. It has been accepted that a maladaptive modulation of inflammatory responses plays a critical role in the development of the disease. Regulatory T cells (Treg) are a subset of T CD4(+) lymphocytes that modulate the immune response through secretion of cytokines. The role of the Treg cells in chronic obstructive pulmonary disease is not clearly known, that is why it is important to focus in understanding their participation in the pathogenesis of the disease. To elaborate a systematic review of original articles in which we could describe Treg cells (their ontogeny, mechanisms of action) and their role in COPD, we made a systematic literature search in some data bases (MEDLINE, AMED, PubMed and Scielo) looking through the next keywords: "COPD and Regulatory T cells/EPOC y células T reguladoras", «Inflammation and COPD/Inflamación y EPOC», «Regulatory T cells/Células T reguladoras». We included basic science articles, controlled and non-controlled clinical trials, meta-analysis and guides. From this search we conclude that Treg cells are a subpopulation of T CD4(+) lymphocytes and their major functions are the suppression of immune responses and the maintenance of tolerance to self-antigens. A disruption in the regulatory mechanisms of the Treg cells leads to the development and perpetuation of inflammation in COPD. PMID:23474149

  6. Role of IL-10-producing regulatory B cells in modulating T-helper cell immune responses during silica-induced lung inflammation and fibrosis.

    PubMed

    Liu, Fangwei; Dai, Wujing; Li, Chao; Lu, Xiaowei; Chen, Ying; Weng, Dong; Chen, Jie

    2016-01-01

    Silicosis is characterized by chronic lung inflammation and fibrosis, which are seriously harmful to human health. Previous research demonstrated that uncontrolled T-helper (Th) cell immune responses were involved in the pathogenesis of silicosis. Lymphocytes also are reported to have important roles. Existing studies on lymphocyte regulation of Th immune responses were limited to T cells, such as the regulatory T (Treg) cell, which could negatively regulate inflammation and promote the process of silicosis. However, other regulatory subsets in silicosis have not been investigated in detail, and the mechanism of immune homeostasis modulation needs further exploration. Another regulatory lymphocyte, the regulatory B cell, has recently drawn increasing attention. In this study, we comprehensively showed the role of IL-10-producing regulatory B cell (B10) in a silicosis model of mice. B10 was inducible by silica instillation. Insufficient B10 amplified inflammation and attenuated lung fibrosis by promoting the Th1 immune response. Insufficient B10 clearly inhibited Treg and decreased the level of IL-10. Our study indicated that B10 could control lung inflammation and exacerbate lung fibrosis by inhibiting Th1 response and modulating the Th balance. The regulatory function of B10 could be associated with Treg induction and IL-10 secretion. PMID:27354007

  7. Role of IL-10-producing regulatory B cells in modulating T-helper cell immune responses during silica-induced lung inflammation and fibrosis

    PubMed Central

    Liu, Fangwei; Dai, Wujing; Li, Chao; Lu, Xiaowei; Chen, Ying; Weng, Dong; Chen, Jie

    2016-01-01

    Silicosis is characterized by chronic lung inflammation and fibrosis, which are seriously harmful to human health. Previous research demonstrated that uncontrolled T-helper (Th) cell immune responses were involved in the pathogenesis of silicosis. Lymphocytes also are reported to have important roles. Existing studies on lymphocyte regulation of Th immune responses were limited to T cells, such as the regulatory T (Treg) cell, which could negatively regulate inflammation and promote the process of silicosis. However, other regulatory subsets in silicosis have not been investigated in detail, and the mechanism of immune homeostasis modulation needs further exploration. Another regulatory lymphocyte, the regulatory B cell, has recently drawn increasing attention. In this study, we comprehensively showed the role of IL-10-producing regulatory B cell (B10) in a silicosis model of mice. B10 was inducible by silica instillation. Insufficient B10 amplified inflammation and attenuated lung fibrosis by promoting the Th1 immune response. Insufficient B10 clearly inhibited Treg and decreased the level of IL-10. Our study indicated that B10 could control lung inflammation and exacerbate lung fibrosis by inhibiting Th1 response and modulating the Th balance. The regulatory function of B10 could be associated with Treg induction and IL-10 secretion. PMID:27354007

  8. Direct-to-Consumer Stem Cell Marketing and Regulatory Responses

    PubMed Central

    2013-01-01

    Summary There is a large, poorly regulated international market of putative stem cell products, including transplants of processed autologous stem cells from various tissues, cell processing devices, cosmetics, and nutritional supplements. Despite the absence of rigorous scientific research in the form of randomized clinical trials to support the routine use of such products, the market appears to be growing and diversifying. Very few stem cell biologics have passed regulatory scrutiny, and authorities in many countries, including the United States, have begun to step up their enforcement activities to protect patients and the integrity of health care markets. PMID:23934911

  9. Direct-to-consumer stem cell marketing and regulatory responses.

    PubMed

    Sipp, Douglas

    2013-09-01

    There is a large, poorly regulated international market of putative stem cell products, including transplants of processed autologous stem cells from various tissues, cell processing devices, cosmetics, and nutritional supplements. Despite the absence of rigorous scientific research in the form of randomized clinical trials to support the routine use of such products, the market appears to be growing and diversifying. Very few stem cell biologics have passed regulatory scrutiny, and authorities in many countries, including the United States, have begun to step up their enforcement activities to protect patients and the integrity of health care markets. PMID:23934911

  10. T Regulatory Cell Biology in Health and Disease.

    PubMed

    Alroqi, Fayhan J; Chatila, Talal A

    2016-04-01

    Regulatory T (Treg) cells that express the transcription factor forkhead box protein P3 (FOXP3) play an essential role in enforcing immune tolerance to self tissues, regulating host-commensal flora interaction, and facilitating tissue repair. Their deficiency and/or dysfunction trigger unbridled autoimmunity and inflammation. A growing number of monogenic defects have been recognized that adversely impact Treg cell development, differentiation, and/or function, leading to heritable diseases of immune dysregulation and autoimmunity. In this article, we review recent insights into Treg cell biology and function, with particular attention to lessons learned from newly recognized clinical disorders of Treg cell deficiency. PMID:26922942

  11. Role of regulatory b cells in neuroimmunologic disorders.

    PubMed

    Han, Jinming; Sun, Li; Fan, Xueli; Wang, Zhongkun; Cheng, Yun; Zhu, Jie; Jin, Tao

    2016-08-01

    B lymphocytes augment the immune response by producing antibodies and activating T cells by antigen presentation. Recent studies have highlighted a specific and functionally significant B-cell subset that could downregulate excessive immune and inflammatory responses through a vast array of inhibitory cytokines, such as interleukin (IL)-10 and transforming growth factor-β (TGF-β). This subset of B cells is generally referred to as regulatory B cells (Bregs). In addition, recent studies have shown that IL-35-producing Bregs also play a role in downregulation of immunity. Diverse phenotypes of Bregs have been proposed to underlie human disorders and their animal models. Most studies have focused on the role of different subsets of Bregs and Bregs-associated molecules such as IL-10, TGF-β, and IL-35 in the pathogenesis of neuroimmunologic disorders. Furthermore, Bregs exert regulatory function mainly through suppressing the differentiation of Th1/Th17 cells and promoting regulatory T-cell expansion. Reduced presence of Bregs is reportedly associated with progression of several neuroimmunologic disorders. This Review summarizes the current knowledge on the role of Bregs in neuroimmunologic disorders, including multiple sclerosis, neuromyelitis optica, and myasthenia gravis. © 2016 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc. PMID:27112131

  12. Regulatory T Cells: Molecular Actions on Effector Cells in Immune Regulation

    PubMed Central

    Arce-Sillas, Asiel; Álvarez-Luquín, Diana Denisse; Tamaya-Domínguez, Beatriz; Gomez-Fuentes, Sandra; Trejo-García, Abel; Melo-Salas, Marlene; Cárdenas, Graciela; Rodríguez-Ramírez, Juan; Adalid-Peralta, Laura

    2016-01-01

    T regulatory cells play a key role in the control of the immune response, both in health and during illness. While the mechanisms through which T regulatory cells exert their function have been extensively described, their molecular effects on effector cells have received little attention. Thus, this revision is aimed at summarizing our current knowledge on those regulation mechanisms on the target cells from a molecular perspective. PMID:27298831

  13. Adenosine influences myeloid cells to inhibit aeroallergen sensitization.

    PubMed

    Pei, Hong; Linden, Joel

    2016-05-15

    Agonists of adenosine A2A receptors (A2ARs) suppress the activation of most immune cells and reduce acute inflammatory responses. Asthma is characterized by sensitization in response to initial allergen exposure and by airway hyperreactivity in response to allergen rechallenge. We sought to determine if A2AR activation with CGS-21680 (CGS) is more effective when CGS is administered during sensitization or rechallenge. C57BL/6 wild-type mice and Adora2a(f/f)LysMCre(+/-) mice, which lack A2ARs on myeloid cells, were sensitized with intranasal ovalbumin (OVA) and LPS. Airway sensitization was characterized by a rapid increase in numbers of IL-6(+) and IL-12(+) macrophages and dendritic cells in lungs. A2AR activation with CGS (0.1 μg·kg(-1)·min(-1) sc) only during sensitization reduced numbers of IL-6(+) and IL-12(+) myeloid cells in the lungs and reversed the effects of OVA rechallenge to increase airway hyperresponsiveness to methacholine. CGS treatment during sensitization also reduced the expansion of lung T helper (Th1 and Th17) cells and increased expansion of regulatory T cells in response to OVA rechallenge. Most of the effects of CGS administered during sensitization were eliminated by myeloid-selective A2AR deletion. Administration of CGS only during OVA rechallenge failed to reduce airway hyperresponsiveness. We conclude that myeloid cells are key targets of adenosine during sensitization and indirectly modify T cell polarization. The results suggest that a clinically useful strategy might be to use A2AR agonists to inhibit sensitization to new aeroallergens. We speculate that adenosine production by macrophages engulfing bacteria contributes to the curious suppression of sensitization in response to early-life infections. PMID:27016586

  14. Regulatory T cells enhance mast cell production of IL-6 via surface-bound TGF-β.

    PubMed

    Ganeshan, Kirthana; Bryce, Paul J

    2012-01-15

    Mast cell degranulation is a hallmark of allergic reactions, but mast cells can also produce many cytokines that modulate immunity. Recently, CD25(+) regulatory T cells (Tregs) have been shown to inhibit mast cell degranulation and anaphylaxis, but their influence on cytokine production remained unknown. In this study, we show that, rather than inhibit, Tregs actually enhance mast cell production of IL-6. We demonstrate that, whereas inhibition of degranulation was OX40/OX40 ligand dependent, enhancement of IL-6 was due to TGF-β. Interestingly, our data demonstrate that the Treg-derived TGF-β was surface-bound, because the interaction was contact dependent, and no TGF-β was detectable in the supernatant. Soluble TGF-β1 alone was sufficient to enhance mast cell IL-6 production, and these supernatants were sufficient to promote Th17 skewing, but those from Treg-mast cell cultures were not, supporting this being surface-bound TGF-β from the Tregs. Interestingly, the augmentation of IL-6 production occurred basally or in response to innate stimuli (LPS or peptidoglycan), adaptive stimuli (IgE cross-linking by specific Ag), and cytokine activation (IL-33). We demonstrate that TGF-β led to enhanced transcription and de novo synthesis of IL-6 upon activation without affecting IL-6 storage or mRNA stability. In vivo, the adoptive transfer of Tregs inhibited mast cell-dependent anaphylaxis in a model of food allergy but promoted intestinal IL-6 and IL-17 production. Consequently, our findings establish that Tregs can exert divergent influences upon mast cells, inhibiting degranulation via OX40/OX40 ligand interactions while promoting IL-6 via TGF-β. PMID:22156492

  15. Regulatory B cells contribute to the impaired antitumor immunity in ovarian cancer patients.

    PubMed

    Wei, Xin; Jin, Yangqiu; Tian, Yinpu; Zhang, Huiyuan; Wu, Jie; Lu, Wei; Lu, Xiaofen

    2016-05-01

    Multiple factors in the tumor microenvironment were found to inhibit antitumor adaptive immune responses, allowing tumor persistence and growth. In this study, ascites from ovarian cancer patients were collected. We observed that a population of interleukin-10(+) B (IL-10(+) B) cells was preferentially enriched in the ascites. This population was associated with naive B cell phenotype or IgM or class-switched memory B cell phenotypes. The frequencies of IL-10(+) B cells were negatively correlated with the frequencies of interferon gamma-producing (IFN-g(+)) CD8(+) T cells and were positively correlated with the frequencies of Foxp3(+) CD4(+) T cells. To examine whether increased IL-10(+) B cells in ascites could directly result in increased suppression of IFN-g production by CD8(+) T cells, we cocultured CD8(+) T cells with autologous blood B cells or ascitic B cells and found that CD8(+) T cells cocultured with ascitic B cells demonstrated significantly suppressed IFN-g production. This suppression was in part mediated by IL-10 as well as low CD80/CD86 expression, since depletion of IL-10 and stimulation of CD28 partially reverted IL-10(+) B cell-mediated suppression. Together, these data demonstrated an additional regulatory mechanism in the tumor microenvironment, which utilizes IL-10(+) B cells. PMID:26638169

  16. Stat3 Is Important for Follicular Regulatory T Cell Differentiation

    PubMed Central

    Wu, Hao; Xie, Markus M.; Liu, Hong; Dent, Alexander L.

    2016-01-01

    The production of antibody is precisely controlled during the germinal center (GC) reaction. This process is dependent on the help from follicular T helper (Tfh) cells to germinal center (GC) B cells and is regulated by regulatory follicular T helper (Tfr) cells. How Tfr cells develop and how their suppressive activity functions are not well understood. Here, we found that Stat3 is indispensible for Tfr cell differentiation. After immunization with Sheep Red Blood Cells (SRBC), the loss of Tfr cells caused by deletion of Stat3 in Treg cells does not affect the size of Tfh or GC B cell population, but rather leads to strongly enhanced production of antigen-specific IgG1 and IgG2b. In Peyer’s patches (PPs) in the gut, we found that Stat3 expression in Treg cells is also required for Tfr cell formation to commensal organisms. However, loss of Tfr cells in the gut did not affect the numbers of Tfh cells and GC B cells, nor affect IgG1 or IgA switching by GC B cells. Overall, our study has uncovered unique roles of Stat3 in Tfr cell differentiation and the regulation of the antibody response. PMID:27148746

  17. Fibroblast Growth Factor-23-mediated Inhibition of Renal Phosphate Transport in Mice Requires Sodium-Hydrogen Exchanger Regulatory Factor-1 (NHERF-1) and Synergizes with Parathyroid Hormone*

    PubMed Central

    Weinman, Edward J.; Steplock, Deborah; Shenolikar, Shirish; Biswas, Rajatsubhra

    2011-01-01

    Fibroblast growth factor-23 (FGF-23) inhibits sodium-dependent phosphate transport in brush border membrane vesicles derived from hormone-treated kidney slices of the mouse and in mouse proximal tubule cells by processes involving mitogen-activated protein kinase (MAPK) but not protein kinase A (PKA) or protein kinase C (PKC). By contrast, phosphate transport in brush border membrane vesicles and proximal tubule cells from sodium-hydrogen exchanger regulatory factor-1 (NHERF-1)-null mice were resistant to the inhibitory effect of FGF-23 (10−9 m). Infection of NHERF-1-null proximal tubule cells with wild-type adenovirus-GFP-NHERF-1 increased basal phosphate transport and restored the inhibitory effect of FGF-23. Infection with adenovirus-GFP-NHERF-1 containing a S77A or T95D mutation also increased basal phosphate transport, but the cells remained resistant to FGF-23 (10−9 m). Low concentrations of FGF-23 (10−13 m) and PTH (10−11 m) individually did not inhibit phosphate transport or activate PKA, PKC, or MAPK. When combined, however, these hormones markedly inhibited phosphate transport associated with activation of PKC and PKA but not MAPK. These studies indicate that FGF-23 inhibits phosphate transport in the mouse kidney by processes that involve the scaffold protein NHERF-1. In addition, FGF-23 synergizes with PTH to inhibit phosphate transport by facilitating the activation of the PTH signal transduction pathway. PMID:21908609

  18. Deciphering cis-regulatory control in inflammatory cells.

    PubMed

    Ghisletti, Serena; Natoli, Gioacchino

    2013-01-01

    In innate immune system cells, such as macrophages and dendritic cells, deployment of inducible gene expression programmes in response to microbes and danger signals requires highly precise regulatory mechanisms. The inflammatory response has to be tailored based on both the triggering stimulus and its dose, and it has to be unfolded in a kinetically complex manner that suits the different phases of the inflammatory process. Genomic characterization of regulatory elements in this context indicated that transcriptional regulators involved in macrophage specification act as pioneer transcription factors (TFs) that generate regions of open chromatin that enable the recruitment of TFs activated in response to external inputs. Therefore, competence for responses to a specific stimulus is programmed at an early stage of differentiation by factors involved in lineage commitment and maintenance of cell identity, which are responsible for the organization of a cell-type-specific cis-regulatory repertoire. The basic functional and organizational principles that regulate inflammatory gene expression in professional cells of the innate immune system provide general paradigms on the interplay between differentiation and environmental responses. PMID:23650641

  19. 3D Chromosome Regulatory Landscape of Human Pluripotent Cells.

    PubMed

    Ji, Xiong; Dadon, Daniel B; Powell, Benjamin E; Fan, Zi Peng; Borges-Rivera, Diego; Shachar, Sigal; Weintraub, Abraham S; Hnisz, Denes; Pegoraro, Gianluca; Lee, Tong Ihn; Misteli, Tom; Jaenisch, Rudolf; Young, Richard A

    2016-02-01

    In this study, we describe the 3D chromosome regulatory landscape of human naive and primed embryonic stem cells. To devise this map, we identified transcriptional enhancers and insulators in these cells and placed them within the context of cohesin-associated CTCF-CTCF loops using cohesin ChIA-PET data. The CTCF-CTCF loops we identified form a chromosomal framework of insulated neighborhoods, which in turn form topologically associating domains (TADs) that are largely preserved during the transition between the naive and primed states. Regulatory changes in enhancer-promoter interactions occur within insulated neighborhoods during cell state transition. The CTCF anchor regions we identified are conserved across species, influence gene expression, and are a frequent site of mutations in cancer cells, underscoring their functional importance in cellular regulation. These 3D regulatory maps of human pluripotent cells therefore provide a foundation for future interrogation of the relationships between chromosome structure and gene control in development and disease. PMID:26686465

  20. Sorafenib induces apoptosis in HL60 cells by inhibiting Src kinase-mediated STAT3 phosphorylation.

    PubMed

    Zhao, Wei; Zhang, Tao; Qu, Bingqian; Wu, Xingxin; Zhu, Xu; Meng, Fanyu; Gu, Yanhong; Shu, Yongqian; Shen, Yan; Sun, Yang; Xu, Qiang

    2011-01-01

    Signal transducer and activator of transcription 3 (STAT3) is constitutively active in approximately 50% of acute myeloid leukemia (AML) cases and mediates multiple cellular processes including cell resistance to apoptosis. Inhibition of constitutively active STAT3 has been shown to induce AML cell apoptosis. Our aim was to ascertain if sorafenib, a multikinase inhibitor, may also inhibit STAT3 signaling and, therefore, be efficacious for AML. We found that sorafenib inhibited proliferation and induced apoptosis in human AML cell line (HL60) cells. In addition, sorafenib exposure reduced constitutive STAT3 phosphorylation in HL60 cells and repressed STAT3 DNA-binding activity and Mcl-1 and Bcl-2 expression. Similar results were obtained with the Src kinase inhibitor I, suggesting that sorafenib suppresses STAT3 phosphorylation by inhibiting Src-kinase activity. Furthermore, significant inhibition of Src kinase activity by sorafenib was observed in the kinase assay. In addition, Src could be co-immunoprecipitated with STAT3, and the phosphorylation of STAT3 was significantly inhibited by sorafenib only in cell lines in which phosphorylated Src is highly expressed. Taken together, our study indicates that sorafenib blocks Src kinase-mediated STAT3 phosphorylation and decreases the expression of apoptosis regulatory proteins Mcl-1 and Bcl-2, which are associated with increased apoptosis in HL60 cells. These findings provide a rationale for the treatment of human AML. PMID:20881478

  1. INTERFERON REGULATORY FACTOR 4 AND 8 IN B CELL DEVELOPMENT

    PubMed Central

    Lu, Runqing

    2010-01-01

    IRF4 and 8 are members of the interferon regulatory factor family of transcription factors and have been shown to be essential for the development and function of T cells, macrophages and dendritic cells. A series of recent studies have further demonstrated critical functions for IRF4 and 8 at several stages of B cell development including pre-B cell development, receptor editing, germinal center reaction and plasma cell generation. Collectively, these new studies provide molecular insights into the function of IRF4 and 8 and underscore a requirement for IRF4 and 8 throughout B cell development. This review focuses on the recent advances on roles of IRF4 and 8 in B cell development. PMID:18775669

  2. Single-cell chromatin accessibility reveals principles of regulatory variation.

    PubMed

    Buenrostro, Jason D; Wu, Beijing; Litzenburger, Ulrike M; Ruff, Dave; Gonzales, Michael L; Snyder, Michael P; Chang, Howard Y; Greenleaf, William J

    2015-07-23

    Cell-to-cell variation is a universal feature of life that affects a wide range of biological phenomena, from developmental plasticity to tumour heterogeneity. Although recent advances have improved our ability to document cellular phenotypic variation, the fundamental mechanisms that generate variability from identical DNA sequences remain elusive. Here we reveal the landscape and principles of mammalian DNA regulatory variation by developing a robust method for mapping the accessible genome of individual cells by assay for transposase-accessible chromatin using sequencing (ATAC-seq) integrated into a programmable microfluidics platform. Single-cell ATAC-seq (scATAC-seq) maps from hundreds of single cells in aggregate closely resemble accessibility profiles from tens of millions of cells and provide insights into cell-to-cell variation. Accessibility variance is systematically associated with specific trans-factors and cis-elements, and we discover combinations of trans-factors associated with either induction or suppression of cell-to-cell variability. We further identify sets of trans-factors associated with cell-type-specific accessibility variance across eight cell types. Targeted perturbations of cell cycle or transcription factor signalling evoke stimulus-specific changes in this observed variability. The pattern of accessibility variation in cis across the genome recapitulates chromosome compartments de novo, linking single-cell accessibility variation to three-dimensional genome organization. Single-cell analysis of DNA accessibility provides new insight into cellular variation of the 'regulome'. PMID:26083756

  3. Induction of Human Regulatory T Cells with Bacterial Superantigens.

    PubMed

    Caserta, Stefano; Taylor, Amanda L; Terrazzini, Nadia; Llewelyn, Martin J

    2016-01-01

    Regulatory T cells (Tregs) that suppress the activation of immune effector cells limit immunopathology and are fast emerging as therapeutic targets for autoimmune and cancer disease. Tools enabling Treg in vitro-induction, expansion, and characterization and manipulation will help future clinical developments. In this chapter, we describe in detail how to use bacterial superantigens to induce human Tregs efficiently from peripheral blood mononuclear cells. How to assess human Treg phenotype and suppressive capacity are also described. Technical details, variations, and alternative experimental conditions are provided. PMID:26676048

  4. Regulatory effects on the population dynamics and wave propagation in a cell lineage model.

    PubMed

    Wang, Mao-Xiang; Ma, Yu-Qiang; Lai, Pik-Yin

    2016-03-21

    We consider the interplay of cell proliferation, cell differentiation (and de-differentiation), cell movement, and the effect of feedback regulations on the population and propagation dynamics of different cell types in a cell lineage model. Cells are assumed to secrete and respond to negative feedback molecules which act as a control on the cell lineage. The cell densities are described by coupled reaction-diffusion partial differential equations, and the propagating wave front solutions in one dimension are investigated analytically and by numerical solutions. In particular, wavefront propagation speeds are obtained analytically and verified by numerical solutions of the equations. The emphasis is on the effects of the feedback regulations on different stages in the cell lineage. It is found that when the progenitor cell is negatively regulated, the populations of the cell lineage are strongly down-regulated with the steady growth rate of the progenitor cell being driven to zero beyond a critical regulatory strength. An analytic expression for the critical regulation strength in terms of the model parameters is derived and verified by numerical solutions. On the other hand, if the inhibition is acting on the differentiated cells, the change in the population dynamics and wave propagation speed is small. In addition, it is found that only the propagating speed of the progenitor cells is affected by the regulation when the diffusion of the differentiated cells is large. In the presence of de-differentiation, the effect on down-regulating the progenitor population is weakened and there is no effect on the propagation speed due to regulation, suggesting that the effect of regulatory control is diminished by de-differentiation pathways. PMID:26796226

  5. A novel regulatory mechanism of naringenin through inhibition of T lymphocyte function in contact hypersensitivity suppression

    SciTech Connect

    Fang, Feng; Tang, Yijun; Gao, Zhe; Xu, Qiang

    2010-06-25

    Naringenin, a flavonoid in grapefruits and citrus fruits, has been reported to exhibit anti-inflammatory and anti-oxidative activities. Contact hypersensitivity (CHS) is a T cell-mediated immune reaction, and the factors released from macrophages also contribute to this response. Previous studies showed that naringenin suppressed CHS by inhibiting activation and migration of macrophages. However, little is known about naringenin's effects on T lymphocytes. Our study indicated that naringenin potently suppressed picryl chloride (PCl)-induced contact hypersensitivity by inhibiting the proliferation and activation of T lymphocytes. In vitro, both of the activated hapten-specific T cells and the T cells stimulated with anti-CD3/anti-CD28 showed growth arrest after naringenin treatment. Furthermore, naringenin reduced CD69 (the protein level) and cytokines such as IL-2, TNF-{alpha}, and IFN-{gamma} (the mRNA level) expressions which highly expressed by activated T cells. Meanwhile, naringenin also induced T cell apoptosis by upregulation of Bax, Bad, PARP, cleaved-caspase 3 and downregulation of phosphorylated Akt, Bcl-2. These findings suggest that, besides its anti-inflammatory activities in macrophages, naringenin also showed inhibitory effects on the activation and proliferation of T cells to alleviate symptoms of contact hypersensitivity.

  6. Novel Foxp3− IL-10− Regulatory T-cells Induced by B-Cells Alleviate Intestinal Inflammation in Vivo

    PubMed Central

    Shao, Tzu-Yu; Hsu, Ling-Hui; Chien, Chien-Hui; Chiang, Bor-Luen

    2016-01-01

    Recent studies have revealed various Foxp3− regulatory T (Treg) cell subsets effectively protect mice from colitis. In the present study, we demonstrated that B cells induced a particular subset of regulatory T (Treg-of-B) cells, expressing programmed cell death 1 (PD-1), inducible costimulator (ICOS), lymphocyte-activation gene 3 (LAG3), glucocorticoid-induced tumor necrosis factor receptor (GITR), and OX-40, did not express Foxp3. Treg-of-B cells produced abundant levels of IL-10 and low levels of IL-4 and TGF-β. Adoptive transfer of Treg-of-B cells protected mice from CD4+CD45RBhi T-cell-induced colitis, including infiltration of leukocytes, depletion of goblet cells, epithelial hyperplasia, and inhibition of Th1 and Th17 cytokines. These features were similar to IL-10-producing type 1 regulatory T (Tr1) cells; however, IL-10-deficient Treg-of-B cells maintained their suppressive function in vitro as well as in vivo, while the regulation of Tr1 cells depended on IL-10. In conclusion, Treg-of-B cells protected against experimental colitis through an IL-10-independent mechanism. We reported a novel subpopulation of regulatory T cells was different from conventional Foxp3+ Treg and IL-10-producing Tr1 cells. PMID:27581189

  7. MET Inhibition in Clear Cell Renal Cell Carcinoma

    PubMed Central

    Xie, Zuoquan; Lee, Young H.; Boeke, Marta; Jilaveanu, Lucia B.; Liu, Zongzhi; Bottaro, Donald P.; Kluger, Harriet M.; Shuch, Brian

    2016-01-01

    Background: Clear cell renal cell carcinoma (ccRCC) is the most lethal form of kidney cancer. Small molecule VEGFR inhibitors are widely used but are not curative and various resistance mechanisms such as activation of the MET pathway have been described. Dual MET/VEGFR2 inhibitors have recently shown clinical benefit but limited preclinical data evaluates their effects in ccRCC. Methods: An interrogation of the Cancer Genome Atlas (TCGA) dataset was performed to evaluate oncogenic alterations in the MET/VEGFR2 pathway. We evaluated the in vitro effects of Cabozantinib, a dual MET/VEGFR2 inhibitor, using a panel of ccRCC cell lines. Drug effects of cell viability and proliferation, migration, cell scatter, anchorage independent growth, and downstream MET/VEGFR2 signaling pathways were assessed. Results: Twelve percent of TCGA cases had possible MET/HGF oncogenic alterations with co-occurrence noted (p<0.001). MET/HGF altered cases had worse overall survival (p=0.044). Cabozantinib was a potent inhibitor of MET and VEGFR2 in vitro in our cell line panel. PI3K, MAPK and mTOR pathways were also suppressed by cabozantinib, however the effects on cell viability in vitro were modest. At nanomolar concentrations of cabozantinib, HGF-stimulated migration, invasion, cellular scattering and soft agar colony formation were inhibited. Conclusions: We provide further preclinical rationale for dual MET/VEGFR2 inhibition in ccRCC. While the MET pathway is implicated in VEGFR resistance, dual inhibitors may have direct anti-tumor effects in a patient subset with evidence of MET pathway involvement. Cabozantinib is a potent dual MET/VEGFR2 inhibitor, significantly inhibits cell migration and invasion in vitro and likely has anti-angiogenic effects similar to other VEGFR tyrosine kinase inhibitors. Future work involving in vivo models will be useful to better define mechanisms of potential anti-tumor activity. PMID:27390595

  8. Liver type I regulatory T cells suppress germinal center formation in HBV-tolerant mice.

    PubMed

    Xu, Long; Yin, Wenwei; Sun, Rui; Wei, Haiming; Tian, Zhigang

    2013-10-15

    The liver plays a critical role in inducing systemic immune tolerance, for example, during limiting hypersensitivity to food allergy and in rendering acceptance of allotransplant or even hepatotropic pathogens. We investigated the unknown mechanisms of liver tolerance by using an established hepatitis B virus (HBV)-carrier mouse model, and found that these mice exhibited an antigen-specific tolerance toward peripheral HBsAg vaccination, showing unenlarged draining lymph node (DLN), lower number of germinal centers (GC), and inactivation of GC B cells and follicular T helper (Tfh) cells. Both in vivo and in vitro immune responses toward HBsAg were suppressed by mononuclear cells from HBV-carrier mice, which were CD4(+) Foxp3(-) type 1 regulatory T (Tr1)-like cells producing IL-10. Using recipient Rag1(-/-) mice, hepatic Tr1-like cells from day 7 of HBV-persistent mice acquired the ability to inhibit anti-HBV immunity 3 d earlier than splenic Tr1-like cells, implying that hepatic Tr1-like cells were generated before those in spleen. Kupffer cell depletion or IL-10 deficiency led to impairment of Tr1-like cell generation, along with breaking HBV persistence. The purified EGFP(+)CD4(+) T cells (containing Tr1-like cells) from HBV-carrier mice trafficked in higher numbers to DLN in recipient mice after HBsAg vaccination, and subsequently inactivated both Tfh cells and GC B cells via secreting IL-10, resulting in impaired GC formation and anti-HB antibody production. Thus, our results indicate Tr1-like cells migrate from the liver to the DLN and inhibit peripheral anti-HBV immunity by negatively regulating GC B cells and Tfh cells. PMID:24089450

  9. The mechanism of potent GTP cyclohydrolase I inhibition by 2,4-diamino-6-hydroxypyrimidine: requirement of the GTP cyclohydrolase I feedback regulatory protein.

    PubMed

    Kolinsky, Monica A; Gross, Steven S

    2004-09-24

    Inhibition of GTP cyclohydrolase I (GTPCH) has been used as a selective tool to assess the role of de novo synthesis of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) in a biological system. Toward this end, 2,4-diamino-6-hydroxypyrimidine (DAHP) has been used as the prototypical GTPCH inhibitor. Using a novel real-time kinetic microplate assay for GTPCH activity and purified prokaryote-expressed recombinant proteins, we show that potent inhibition by DAHP is not the result of a direct interaction with GTPCH. Rather, inhibition by DAHP in phosphate buffer occurs via an indirect mechanism that requires the presence of GTPCH feedback regulatory protein (GFRP). Notably, GFRP was previously discovered as the essential factor that reconstitutes inhibition of pure recombinant GTPCH by the pathway end product BH4. Thus, DAHP inhibits GTPCH by engaging the endogenous feedback inhibitory system. We further demonstrate that L-Phe fully reverses the inhibition of GTPCH by DAHP/GFRP, which is also a feature in common with inhibition by BH4/GFRP. These findings suggest that DAHP is not an indiscriminate inhibitor of GTPCH in biological systems; instead, it is predicted to preferentially attenuate GTPCH activity in cells that most abundantly express GFRP and/or contain the lowest levels of L-Phe. PMID:15292175

  10. Role of regulatory dendritic cells in allergy and asthma.

    PubMed

    Akbari, Omid; Umetsu, Dale T

    2005-01-01

    Dendritic cells (DCs) are the most efficient inducers of all immune responses, and are capable of either inducing productive immunity or maintaining the state of tolerance to self antigens and allergens. In this review, we summarize the emerging literature on DCs, with emphasis on the regulatory function of DCs in allergy and asthma. In particular, we summarize recent data regarding the relationship between DC subsets and TH1, TH2, and regulatory T (TReg) cells. The diverse functions of DCs have been attributed to distinct lineages of DCs, which arise from common immature precursor cells that differentiate in response to specific maturation-inducing or local microenvironment conditions. These subsets of DCs induce different lineages of T cells, such as TH1, TH2, and TReg cells, including Th1Reg and Th2Reg cells, which regulate allergic diseases and asthma. Subsets of DCs regulate the induction of a variety of T-cell subtypes, which suppress the development of allergy and asthma, thus providing anti-inflammatory responses and protective immunity. PMID:15659264

  11. Regulatory T Cells Control Th2-Dominant Murine Autoimmune Gastritis.

    PubMed

    Harakal, Jessica; Rival, Claudia; Qiao, Hui; Tung, Kenneth S

    2016-07-01

    Pernicious anemia and gastric carcinoma are serious sequelae of autoimmune gastritis (AIG). Our study indicates that in adult C57BL/6-DEREG mice expressing a transgenic diphtheria toxin receptor under the Foxp3 promoter, transient regulatory T cell (Treg) depletion results in long-lasting AIG associated with both H(+)K(+)ATPase and intrinsic factor autoantibody responses. Although functional Tregs emerge over time during AIG occurrence, the effector T cells rapidly become less susceptible to Treg-mediated suppression. Whereas previous studies have implicated dysregulated Th1 cell responses in AIG pathogenesis, eosinophils have been detected in gastric biopsy specimens from patients with AIG. Indeed, AIG in DEREG mice is associated with strong Th2 cell responses, including dominant IgG1 autoantibodies, elevated serum IgE, increased Th2 cytokine production, and eosinophil infiltration in the stomach-draining lymph nodes. In addition, the stomachs exhibit severe mucosal and muscular hypertrophy, parietal cell loss, mucinous epithelial cell metaplasia, and massive eosinophilic inflammation. Notably, the Th2 responses and gastritis severity are significantly ameliorated in IL-4- or eosinophil-deficient mice. Furthermore, expansion of both Th2-promoting IFN regulatory factor 4(+) programmed death ligand 2(+) dendritic cells and ILT3(+) rebounded Tregs was detected after transient Treg depletion. Collectively, these data suggest that Tregs maintain physiological tolerance to clinically relevant gastric autoantigens, and Th2 responses can be a pathogenic mechanism in AIG. PMID:27259856

  12. Breaking immune tolerance by targeting Foxp3+ regulatory T cells mitigates Alzheimer's disease pathology

    PubMed Central

    Baruch, Kuti; Rosenzweig, Neta; Kertser, Alexander; Deczkowska, Aleksandra; Sharif, Alaa Mohammad; Spinrad, Amit; Tsitsou-Kampeli, Afroditi; Sarel, Ayelet; Cahalon, Liora; Schwartz, Michal

    2015-01-01

    Alzheimer's disease (AD) is a neurodegenerative disorder in which chronic neuroinflammation contributes to disease escalation. Nevertheless, while immunosuppressive drugs have repeatedly failed in treating this disease, recruitment of myeloid cells to the CNS was shown to play a reparative role in animal models. Here we show, using the 5XFAD AD mouse model, that transient depletion of Foxp3+ regulatory T cells (Tregs), or pharmacological inhibition of their activity, is followed by amyloid-β plaque clearance, mitigation of the neuroinflammatory response and reversal of cognitive decline. We further show that transient Treg depletion affects the brain's choroid plexus, a selective gateway for immune cell trafficking to the CNS, and is associated with subsequent recruitment of immunoregulatory cells, including monocyte-derived macrophages and Tregs, to cerebral sites of plaque pathology. Our findings suggest targeting Treg-mediated systemic immunosuppression for treating AD. PMID:26284939

  13. Regulatory T cell homeostasis: steady-state maintenance and modulation during inflammation

    PubMed Central

    Smigiel, Kate S.; Srivastava, Shivani; Stolley, J. Michael; Campbell, Daniel J.

    2014-01-01

    Summary Regulatory T (Treg) cells play a vital role in the prevention of autoimmunity and the maintenance of self-tolerance but also have an active role in inhibiting immune responses during viral, bacterial and parasitic infections. Whereas excessive Treg activity can lead to immunodeficiency, chronic infection and cancer, too little Treg activity results in autoimmunity and immunopathology, and impairs the quality of pathogen-specific responses. Recent studies have helped define the homeostatic mechanisms that support the diverse pool of peripheral Treg cells under steady-state conditions, and delineate how the abundance and function of Treg cells changes during inflammation. These findings are highly relevant for developing effective strategies to manipulate Treg cell activity to promote allograft tolerance and treat autoimmunity, chronic infection and cancer. PMID:24712458

  14. T Cell Receptor Signaling in the Control of Regulatory T Cell Differentiation and Function

    PubMed Central

    Li, Ming O.; Rudensky, Alexander Y.

    2016-01-01

    Regulatory T cells (TReg cells), a specialized T cell lineage, have a pivotal function in the control of self-tolerance and inflammatory responses. Recent studies have revealed a discrete mode of TCR signaling that regulates Treg cell differentiation, maintenance and function and that impacts on gene expression, metabolism, cell adhesion and migration of these cells. Here, we discuss the emerging understanding of TCR-guided differentiation of Treg cells in the context of their function in health and disease. PMID:27026074

  15. Decidual vascular endothelial cells promote maternal-fetal immune tolerance by inducing regulatory T cells through canonical Notch1 signaling.

    PubMed

    Yao, Yanyi; Song, Jieping; Wang, Weipeng; Liu, Nian

    2016-05-01

    Adaptation of the maternal immune response to accommodate the semiallogeneic fetus is necessary for pregnancy success. However, the mechanisms by which the fetus avoids rejection despite expression of paternal alloantigens remain incompletely understood. Regulatory T cells (Treg cells) are pivotal for maintaining immune homeostasis, preventing autoimmune disease and fetus rejection. In this study, we found that maternal decidual vascular endothelial cells (DVECs) sustained Foxp3 expression in resting Treg cells in vitro. Moreover, under in vitro Treg cell induction condition with agonistic antibodies and transforming growth factor (TGF)-β, DVECs promoted Treg cell differentiation from non-Treg conventional T cells. Consistent with the promotion of Treg cell maintenance and differentiation, Treg cell-associated gene expression such as TGF-β, Epstein-Barr-induced gene-3, CD39 and glucocorticoid-induced tumor necrosis factor receptor was also increased in the presence of DVECs. Further study revealed that DVECs expressed Notch ligands such as Jagged-1, Delta-like protein 1 (DLL-1) and DLL-4, while Treg cells expressed Notch1 on their surface. The effects of DVECs on Treg cells was inhibited by siRNA-induced knockdown of expression of Jagged-1 and DLL-1 in DVECs. Downregulation of Notch1 in Treg cells using lentiviral shRNA transduction decreased Foxp3 expression in Treg cells. Adoptive transfer of Notch1-deficient Treg cells increased abortion rate in a murine semiallogeneic pregnancy model. Taken together, our study suggests that maternal DVECs are able to maintain decidual Treg cell identity and promote Treg cell differentiation through activation of Notch1 signal pathway in Treg cells and subsequently inhibit the immune response against semiallogeneic fetuses and preventing spontaneous abortion. PMID:26714886

  16. Glucocorticoid receptor-mediated cell cycle arrest is achieved through distinct cell-specific transcriptional regulatory mechanisms.

    PubMed Central

    Rogatsky, I; Trowbridge, J M; Garabedian, M J

    1997-01-01

    Glucocorticoids inhibit proliferation of many cell types, but the events leading from the activated glucocorticoid receptor (GR) to growth arrest are not understood. Ectopic expression and activation of GR in human osteosarcoma cell lines U2OS and SAOS2, which lack endogenous receptors, result in a G1 cell cycle arrest. GR activation in U2OS cells represses expression of the cyclin-dependent kinases (CDKs) CDK4 and CDK6 as well as their regulatory partner, cyclin D3, leading to hypophosphorylation of the retinoblastoma protein (Rb). We also demonstrate a ligand-dependent reduction in the expression of E2F-1 and c-Myc, transcription factors involved in the G1-to-S-phase transition. Mitogen-activated protein kinase, CDK2, cyclin E, and the CDK inhibitors (CDIs) p27 and p21 are unaffected by receptor activation in U2OS cells. The receptor's N-terminal transcriptional activation domain is not required for growth arrest in U2OS cells. In Rb-deficient SAOS2 cells, however, the expression of p27 and p21 is induced upon receptor activation. Remarkably, in SAOS2 cells that express a GR deletion derivative lacking the N-terminal transcriptional activation domain, induction of CDI expression is abolished and the cells fail to undergo ligand-dependent cell cycle arrest. Similarly, murine S49 lymphoma cells, which, like SAOS2 cells, lack Rb, require the N-terminal activation domain for growth arrest and induce CDI expression upon GR activation. These cell-type-specific differences in receptor domains and cellular targets linking GR activation to cell cycle machinery suggest two distinct regulatory mechanisms of GR-mediated cell cycle arrest: one involving transcriptional repression of G1 cyclins and CDKs and the other involving enhanced transcription of CDIs by the activated receptor. PMID:9154817

  17. Regulatory T cells in immune-mediated renal disease.

    PubMed

    Ghali, Joanna R; Wang, Yuan Min; Holdsworth, Stephen R; Kitching, A Richard

    2016-02-01

    Regulatory T cells (Tregs) are CD4+ T cells that can suppress immune responses by effector T cells, B cells and innate immune cells. This review discusses the role that Tregs play in murine models of immune-mediated renal diseases and acute kidney injury and in human autoimmune kidney disease (such as systemic lupus erythematosus, anti-glomerular basement membrane disease, anti-neutrophil cytoplasmic antibody-associated vasculitis). Current research suggests that Tregs may be reduced in number and/or have impaired regulatory function in these diseases. Tregs possess several mechanisms by which they can limit renal and systemic inflammatory immune responses. Potential therapeutic applications involving Tregs include in vivo induction of Tregs or inducing Tregs from naïve CD4+ T cells or expanding natural Tregs ex vivo, to use as a cellular therapy. At present, the optimal method of generating a phenotypically stable pool of Tregs with long-lasting suppressive effects is not established, but human studies in renal transplantation are underway exploring the therapeutic potential of Tregs as a cellular therapy, and if successful may have a role as a novel therapy in immune-mediated renal diseases. PMID:26206106

  18. Regulatory landscape for cell therapy--EU view.

    PubMed

    McBlane, James W

    2015-09-01

    This article addresses regulation of cell therapies in the European Union (EU), covering cell sourcing and applications for clinical trials and marketing authorisation applications. Regulatory oversight of cell sourcing and review of applications for clinical trials with cell therapies are handled at national level, that is, separately with each country making its own decisions. For clinical trials, this can lead to different decisions in different countries for the same trial. A regulation is soon to come into force that will address this and introduce a more efficient clinical trial application process. However, at the marketing authorisation stage, the process is pan-national: the Committee for Human Medicinal Products (CHMP) is responsible for giving the final scientific opinion on all EU marketing authorisation applications for cell therapies: favourable scientific opinions are passed to the European Commission (EC) for further consultation and, if successful, grant of a marketing authorisation valid in all 28 EU countries. In its review of applications for marketing authorisations (MAAs) for cell therapies, the CHMP is obliged to consult the Committee for Advanced Therapies (CAT), who conduct detailed scientific assessments of these applications, with assessment by staff from national regulatory authorities and specialist advisors to the regulators. PMID:25997566

  19. An Integrated Gene Regulatory Network Controls Stem Cell Proliferation in Teeth

    PubMed Central

    Felszeghy, Szabolcs; Zelarayan, Laura C; Alonso, Maria T; Plikus, Maksim V; Maas, Richard L; Chuong, Cheng-Ming; Schimmang, Thomas; Thesleff, Irma

    2007-01-01

    Epithelial stem cells reside in specific niches that regulate their self-renewal and differentiation, and are responsible for the continuous regeneration of tissues such as hair, skin, and gut. Although the regenerative potential of mammalian teeth is limited, mouse incisors grow continuously throughout life and contain stem cells at their proximal ends in the cervical loops. In the labial cervical loop, the epithelial stem cells proliferate and migrate along the labial surface, differentiating into enamel-forming ameloblasts. In contrast, the lingual cervical loop contains fewer proliferating stem cells, and the lingual incisor surface lacks ameloblasts and enamel. Here we have used a combination of mouse mutant analyses, organ culture experiments, and expression studies to identify the key signaling molecules that regulate stem cell proliferation in the rodent incisor stem cell niche, and to elucidate their role in the generation of the intrinsic asymmetry of the incisors. We show that epithelial stem cell proliferation in the cervical loops is controlled by an integrated gene regulatory network consisting of Activin, bone morphogenetic protein (BMP), fibroblast growth factor (FGF), and Follistatin within the incisor stem cell niche. Mesenchymal FGF3 stimulates epithelial stem cell proliferation, and BMP4 represses Fgf3 expression. In turn, Activin, which is strongly expressed in labial mesenchyme, inhibits the repressive effect of BMP4 and restricts Fgf3 expression to labial dental mesenchyme, resulting in increased stem cell proliferation and a large, labial stem cell niche. Follistatin limits the number of lingual stem cells, further contributing to the characteristic asymmetry of mouse incisors, and on the basis of our findings, we suggest a model in which Follistatin antagonizes the activity of Activin. These results show how the spatially restricted and balanced effects of specific components of a signaling network can regulate stem cell proliferation in

  20. Immune regulatory effects of simvastatin on regulatory T cell-mediated tumour immune tolerance.

    PubMed

    Lee, K J; Moon, J Y; Choi, H K; Kim, H O; Hur, G Y; Jung, K H; Lee, S Y; Kim, J H; Shin, C; Shim, J J; In, K H; Yoo, S H; Kang, K H; Lee, S Y

    2010-08-01

    Statins are potent inhibitors of hydroxyl-3-methylglutaryl co-enzyme A (HMG-CoA) reductase, and have emerged as potential anti-cancer agents based on preclinical evidence. In particular, compelling evidence suggests that statins have a wide range of immunomodulatory properties. However, little is known about the role of statins in tumour immune tolerance. Tumour immune tolerance involves the production of immunosuppressive molecules, such as interleukin (IL)-10, transforming growth factor (TGF)-beta and indoleamine-2,3-dioxygenase (IDO) by tumours, which induce a regulatory T cell (T(reg)) response. In this study, we investigated the effect of simvastatin on the production of IL-10, TGF-beta and IDO production and the proliferation of T(regs) using several cancer cell lines, and Lewis lung cancer (3LL) cells-inoculated mouse tumour model. Simvastatin treatment resulted in a decrease in the number of cancer cells (3LL, A549 and NCI-H292). The production of the immune regulatory markers IL-10, TGF-beta in 3LL and NCI-H292 cells increased after treatment with simvastatin. The expression of IDO and forkhead box P3 (FoxP3) transcription factor was also increased in the presence of simvastatin. In a murine 3LL model, there were no significant differences in tumour growth rate between untreated and simvastatin-treated mice groups. Therefore, while simvastatin had an anti-proliferative effect, it also exhibited immune tolerance-promoting properties during tumour development. Thus, due to these opposing actions, simvastatin had no net effect on tumour growth. PMID:20491794

  1. Regulatory T Cell Dysfunction Acquiesces to BTLA+ Regulatory B Cells Subsequent to Oral Intervention in Experimental Autoimmune Encephalomyelitis.

    PubMed

    Huarte, Eduardo; Jun, SangMu; Rynda-Apple, Agnieszka; Golden, Sara; Jackiw, Larissa; Hoffman, Carol; Maddaloni, Massimo; Pascual, David W

    2016-06-15

    Regulatory T cells (Tregs) induced during autoimmunity often become quiescent and unable to resolve disease, suggesting inadequate activation. Resolution of established experimental autoimmune encephalomyelitis (EAE) can be achieved with myelin oligodendrocyte glycoprotein (MOG) fused to reovirus protein σ1 (MOG-pσ1), which activates Tregs, restoring protection, but requiring other regulatory cells to revitalize them. B cells have a dichotomous role in both the pathogenesis and recovery from EAE. Although inflammatory B cells contribute to EAE's pathogenesis, treatment of EAE mice with MOG-pσ1, but not OVA-pσ1, resulted in an influx of IL-10-producing B220(+)CD5(+) B regulatory cells (Bregs) enabling Tregs to recover their inhibitory activity, and in turn, leading to the rapid amelioration of EAE. These findings implicate direct interactions between Bregs and Tregs to facilitate this recovery. Adoptive transfer of B220(+)CD5(-) B cells from MOG-pσ1-treated EAE or Bregs from PBS-treated EAE mice did not resolve disease, whereas the adoptive transfer of MOG-pσ1-induced B220(+)CD5(+) Bregs greatly ameliorated EAE. MOG-pσ1-, but not OVA-pσ1-induced IL-10-producing Bregs, expressed elevated levels of B and T lymphocyte attenuator (BTLA) relative to CD5(-) B cells, as opposed to Tregs or effector T (Teff) cells, whose BTLA expression was not affected. These induced Bregs restored EAE Treg function in a BTLA-dependent manner. BTLA(-/-) mice showed more pronounced EAE with fewer Tregs, but upon adoptive transfer of MOG-pσ1-induced BTLA(+) Bregs, BTLA(-/-) mice were protected against EAE. Hence, this evidence shows the importance of BTLA in activating Tregs to facilitate recovery from EAE. PMID:27194787

  2. CTLA-4 control over Foxp3+ regulatory T cell function.

    PubMed

    Wing, Kajsa; Onishi, Yasushi; Prieto-Martin, Paz; Yamaguchi, Tomoyuki; Miyara, Makoto; Fehervari, Zoltan; Nomura, Takashi; Sakaguchi, Shimon

    2008-10-10

    Naturally occurring Foxp3+CD4+ regulatory T cells (Tregs) are essential for maintaining immunological self-tolerance and immune homeostasis. Here, we show that a specific deficiency of cytotoxic T lymphocyte antigen 4 (CTLA-4) in Tregs results in spontaneous development of systemic lymphoproliferation, fatal T cell-mediated autoimmune disease, and hyperproduction of immunoglobulin E in mice, and it also produces potent tumor immunity. Treg-specific CTLA-4 deficiency impairs in vivo and in vitro suppressive function of Tregs-in particular, Treg-mediated down-regulation of CD80 and CD86 expression on dendritic cells. Thus, natural Tregs may critically require CTLA-4 to suppress immune responses by affecting the potency of antigen-presenting cells to activate other T cells. PMID:18845758

  3. Transcriptional Regulatory Networks for CD4 T Cell Differentiation

    PubMed Central

    Zhu, Jinfang

    2015-01-01

    CD4+ T cells play a central role in controlling the adaptive immune response by secreting cytokines to activate target cells. Naïve CD4+ T cells differentiate into at least four subsets, Th1, Th2, Th17, and inducible regulatory T cells, each with unique functions for pathogen elimination. The differentiation of these subsets is induced in response to cytokine stimulation, which is translated into Stat activation, followed by induction of master regulator transcription factors. In addition to these factors, multiple other transcription factors, both subset specific and shared, are also involved in promoting subset differentiation. This review will focus on the network of transcription factors that control CD4+ T cell differentiation. PMID:24839135

  4. An Arabidopsis Gene Regulatory Network for Secondary Cell Wall Synthesis

    PubMed Central

    Taylor-Teeples, M; Lin, L; de Lucas, M; Turco, G; Toal, TW; Gaudinier, A; Young, NF; Trabucco, GM; Veling, MT; Lamothe, R; Handakumbura, PP; Xiong, G; Wang, C; Corwin, J; Tsoukalas, A; Zhang, L; Ware, D; Pauly, M; Kliebenstein, DJ; Dehesh, K; Tagkopoulos, I; Breton, G; Pruneda-Paz, JL; Ahnert, SE; Kay, SA; Hazen, SP; Brady, SM

    2014-01-01

    Summary The plant cell wall is an important factor for determining cell shape, function and response to the environment. Secondary cell walls, such as those found in xylem, are composed of cellulose, hemicelluloses and lignin and account for the bulk of plant biomass. The coordination between transcriptional regulation of synthesis for each polymer is complex and vital to cell function. A regulatory hierarchy of developmental switches has been proposed, although the full complement of regulators remains unknown. Here, we present a protein-DNA network between Arabidopsis transcription factors and secondary cell wall metabolic genes with gene expression regulated by a series of feed-forward loops. This model allowed us to develop and validate new hypotheses about secondary wall gene regulation under abiotic stress. Distinct stresses are able to perturb targeted genes to potentially promote functional adaptation. These interactions will serve as a foundation for understanding the regulation of a complex, integral plant component. PMID:25533953

  5. Role of Signal Regulatory Protein α in Arsenic Trioxide-induced Promyelocytic Leukemia Cell Apoptosis.

    PubMed

    Pan, Chaoyun; Zhu, Dihan; Zhuo, Jianjiang; Li, Limin; Wang, Dong; Zhang, Chen-Yu; Liu, Yuan; Zen, Ke

    2016-01-01

    Signal regulatory protein α (SIRPα) has been shown to operate as a negative regulator in cancer cell survival. The mechanism underneath such function, however, remains poorly defined. In the present study, we demonstrate that overexpression of SIRPα in acute promyelocytic leukemia (APL) cells results in apoptosis possibly via inhibiting the β-catenin signaling pathway and upregulating Foxo3a. Pharmacological activation of β-catenin signal pathway attenuates apoptosis caused by SIRPα. Interestingly, we also find that the pro-apoptotic effect of SIRPα plays an important role in arsenic trioxide (ATO)-induced apoptosis in APL cells. ATO treatment induces the SIRPα protein expression in APL cells and abrogation of SIRPα induction by lentivirus-mediated SIRPα shRNA significantly reduces the ATO-induced apoptosis. Mechanistic study further shows that induction of SIRPα protein in APL cells by ATO is mediated through suppression of c-Myc, resulting in reduction of three SIRPα-targeting microRNAs: miR-17, miR-20a and miR-106a. In summary, our results demonstrate that SIRPα inhibits tumor cell survival and significantly contributes to ATO-induced APL cell apoptosis. PMID:27010069

  6. Role of Signal Regulatory Protein α in Arsenic Trioxide-induced Promyelocytic Leukemia Cell Apoptosis

    PubMed Central

    Pan, Chaoyun; Zhu, Dihan; Zhuo, Jianjiang; Li, Limin; Wang, Dong; Zhang, Chen-Yu; Liu, Yuan; Zen, Ke

    2016-01-01

    Signal regulatory protein α (SIRPα) has been shown to operate as a negative regulator in cancer cell survival. The mechanism underneath such function, however, remains poorly defined. In the present study, we demonstrate that overexpression of SIRPα in acute promyelocytic leukemia (APL) cells results in apoptosis possibly via inhibiting the β-catenin signaling pathway and upregulating Foxo3a. Pharmacological activation of β-catenin signal pathway attenuates apoptosis caused by SIRPα. Interestingly, we also find that the pro-apoptotic effect of SIRPα plays an important role in arsenic trioxide (ATO)-induced apoptosis in APL cells. ATO treatment induces the SIRPα protein expression in APL cells and abrogation of SIRPα induction by lentivirus-mediated SIRPα shRNA significantly reduces the ATO-induced apoptosis. Mechanistic study further shows that induction of SIRPα protein in APL cells by ATO is mediated through suppression of c-Myc, resulting in reduction of three SIRPα-targeting microRNAs: miR-17, miR-20a and miR-106a. In summary, our results demonstrate that SIRPα inhibits tumor cell survival and significantly contributes to ATO-induced APL cell apoptosis. PMID:27010069

  7. Diverse Gene Expression in Human Regulatory T Cell Subsets Uncovers Connection between Regulatory T Cell Genes and Suppressive Function.

    PubMed

    Hua, Jing; Davis, Scott P; Hill, Jonathan A; Yamagata, Tetsuya

    2015-10-15

    Regulatory T (Treg) cells have a critical role in the control of immunity, and their diverse subpopulations may allow adaptation to different types of immune responses. In this study, we analyzed human Treg cell subpopulations in the peripheral blood by performing genome-wide expression profiling of 40 Treg cell subsets from healthy donors. We found that the human peripheral blood Treg cell population is comprised of five major genomic subgroups, represented by 16 tractable subsets with a particular cell surface phenotype. These subsets possess a range of suppressive function and cytokine secretion and can exert a genomic footprint on target effector T (Teff) cells. Correlation analysis of variability in gene expression in the subsets identified several cell surface molecules associated with Treg suppressive function, and pharmacological interrogation revealed a set of genes having causative effect. The five genomic subgroups of Treg cells imposed a preserved pattern of gene expression on Teff cells, with a varying degree of genes being suppressed or induced. Notably, there was a cluster of genes induced by Treg cells that bolstered an autoinhibitory effect in Teff cells, and this induction appears to be governed by a different set of genes than ones involved in counteracting Teff activation. Our work shows an example of exploiting the diversity within human Treg cell subpopulations to dissect Treg cell biology. PMID:26371251

  8. CNS accumulation of regulatory B cells is VLA-4-dependent

    PubMed Central

    Lehmann-Horn, Klaus; Sagan, Sharon A.; Winger, Ryan C.; Spencer, Collin M.; Bernard, Claude C.A.; Sobel, Raymond A.

    2016-01-01

    Objective: To investigate the role of very late antigen-4 (VLA-4) on regulatory B cells (Breg) in CNS autoimmune disease. Methods: Experimental autoimmune encephalomyelitis (EAE) was induced in mice selectively deficient for VLA-4 on B cells (CD19cre/α4f/f) by immunization with myelin oligodendrocyte glycoprotein (MOG) peptide (p)35–55 or recombinant human (rh) MOG protein. B-cell and T-cell populations were examined by flow cytometry and immunohistochemistry. Breg were evaluated by intracellular IL-10 staining of B cells and, secondly, by coexpression of CD1d and CD5. Results: As previously reported, EAE was less severe in B-cell VLA-4-deficient vs control CD19cre mice when induced by rhMOG, a model that is B-cell-dependent and leads to efficient B-cell activation and antibody production. Paradoxically, B-cell VLA-4-deficient mice developed more severe clinical disease than control mice when EAE was induced with MOG p35-55, a B-cell-independent encephalitogen that does not efficiently activate B cells. Peripheral T-cell and humoral immune responses were not altered in B-cell VLA-4-deficient mice. In MOG p35-55-induced EAE, B-cell VLA-4 deficiency reduced CNS accumulation of B but not T cells. Breg were detected in the CNS of control mice with MOG p35-55-induced EAE. However, more severe EAE in B-cell VLA-4-deficient mice was associated with virtual absence of CNS Breg. Conclusions: Our results demonstrate that CNS accumulation of Breg is VLA-4-dependent and suggest that Breg may contribute to regulation of CNS autoimmunity in situ. These observations underscore the need to choose the appropriate encephalitogen when studying how B cells contribute to pathogenesis or regulation of CNS autoimmunity. PMID:27027096

  9. Regulatory T cells actively infiltrate metastatic brain tumors.

    PubMed

    Sugihara, Adam Quasar; Rolle, Cleo E; Lesniak, Maciej S

    2009-06-01

    Regulatory T cells (CD4+CD25+FoxP3+, Treg) have been shown to play a major role in suppression of the immune response to malignant gliomas. In this study, we investigated the kinetics of Treg infiltration in metastatic brain tumor models, including melanoma, breast and colon cancers. Our data indicate that both CD4+ and Treg infiltration are significantly increased throughout the time of metastatic tumor progression. These findings were recapitulated in human CNS tumor samples of metastatic melanoma and non-small cell lung carcinoma. Collectively, these data support investigating immunotherapeutic strategies targeting Treg in metastatic CNS tumors. PMID:19424570

  10. Adeno-associated virus type 2 rep gene-mediated inhibition of basal gene expression of human immunodeficiency virus type 1 involves its negative regulatory functions.

    PubMed Central

    Oelze, I; Rittner, K; Sczakiel, G

    1994-01-01

    Adeno-associated virus type 2 (AAV-2), a human parvovirus which is apathogenic in adults, inhibits replication and gene expression of human immunodeficiency virus type 1 (HIV-1) in human cells. The rep gene of AAV-2, which was shown earlier to be sufficient for this negative interference, also down-regulated the expression of heterologous sequences driven by the long terminal repeat (LTR) of HIV-1. This effect was observed in the absence of the HIV-1 transactivator Tat, i.e., at basal levels of LTR-driven transcription. In this work, we studied the involvement of functional subsequences of the HIV-1 LTR in rep-mediated inhibition in the absence of Tat. Mutated LTRs driving an indicator gene (cat) were cointroduced into human SW480 cells together with rep alone or with double-stranded DNA fragments or RNA containing sequences of the HIV-1 LTR. The results indicate that rep strongly enhances the function of negative regulatory elements of the LTR. In addition, the experiments revealed a transcribed sequence element located within the TAR-coding sequence termed AHHH (AAV-HIV homology element derived from HIV-1) which is involved in rep-mediated inhibition. The AHHH element is also involved in down-regulation of basal expression levels in the absence of rep, suggesting that AHHH also contributes to negative regulatory functions of the LTR of HIV-1. In contrast, positive regulatory elements of the HIV-1 LTR such as the NF kappa B and SP1 binding sites have no significant influence on the rep-mediated inhibition. Images PMID:8289357

  11. Polydatin-induced cell apoptosis and cell cycle arrest are potentiated by Janus kinase 2 inhibition in leukemia cells.

    PubMed

    Cao, Wei-Jie; Wu, Ke; Wang, Chong; Wan, Ding-Ming

    2016-04-01

    Polydatin (PD), a natural precursor of resveratrol, has a variety of biological activities, including anti‑tumor effects. However, the underlying molecular mechanisms of the anti-cancer activity of PD has not been fully elucidated. The present study demonstrated that PD significantly inhibited the proliferation of the MOLT-4 leukemia cell line in a dose‑ and time-dependent manner by using Cell Counting Kit‑8 assay. PD also dose-dependently increased the apoptotic rate and caused cell cycle arrest in S phase in MOLT‑4 cells, as revealed by flow cytometry. In addition, PD dose-dependently decreased the mitochondrial membrane potential and led to the generation of reactive oxygen species in MOLT-4 cells. Western blot analysis revealed that the expression of anti‑apoptotic protein B-cell lymphoma 2 (Bcl-2) was decreased, whereas that of pro‑apoptotic protein Bcl‑2‑associated X was increased by PD. Furthermore, the expression of two cell cycle regulatory proteins, cyclin D1 and cyclin B1, was suppressed by PD. Of note, the pro‑apoptotic and cell cycle‑inhibitory effects of PD were potentiated by Janus kinase 2 (JAK2) inhibition. In conclusion, the results of the present study strongly suggested that PD is a promising therapeutic compound for the treatment of leukemia, particularly in combination with JAK inhibitors. PMID:26934953

  12. Helios Controls a Limited Subset of Regulatory T Cell Functions.

    PubMed

    Sebastian, Mathew; Lopez-Ocasio, Maria; Metidji, Amina; Rieder, Sadiye Amcaoglu; Shevach, Ethan M; Thornton, Angela M

    2016-01-01

    A subpopulation (60-70%) of Foxp3(+) regulatory T cells (Tregs) in both mouse and man expresses the transcription factor Helios, but its role in Treg function is still unknown. We generated Treg-specific Helios-deficient mice to examine the function of Helios in Tregs. We show that the selective deletion of Helios in Tregs leads to slow, progressive systemic immune activation, hypergammaglobulinemia, and enhanced germinal center formation in the absence of organ-specific autoimmunity. Helios-deficient Treg suppressor function was normal in vitro, as well as in an in vivo inflammatory bowel disease model. However, Helios-deficient Tregs failed to control the expansion of pathogenic T cells derived from scurfy mice, failed to mediate T follicular regulatory cell function, and failed to control both T follicular helper cell and Th1 effector cell responses. In competitive settings, Helios-deficient Tregs, particularly effector Tregs, were at a disadvantage, indicating that Helios regulates effector Treg fitness. Thus, we demonstrate that Helios controls certain aspects of Treg-suppressive function, differentiation, and survival. PMID:26582951

  13. Blockade of TNF-α signaling benefits cancer therapy by suppressing effector regulatory T cell expansion

    PubMed Central

    Chang, Li-Yuan; Lin, Yung-Chang; Chiang, Jy-Ming; Mahalingam, Jayashri; Su, Shih-Huan; Huang, Ching-Tai; Chen, Wei-Ting; Huang, Chien-Hao; Jeng, Wen-Juei; Chen, Yi-Cheng; Lin, Shi-Ming; Sheen, I-Shyan; Lin, Chun-Yen

    2015-01-01

    Effector but not naive regulatory T cells (Treg cells) can accumulate in the peripheral blood as well as the tumor microenvironment, expand during tumor progression and be one of the main suppressors for antitumor immunity. However, the underlying mechanisms for effector Treg cell expansion in tumor are still unknown. We demonstrate that effector Treg cell-mediated suppression of antitumor CD8+ T cells is tumor-nonspecific. Furthermore, TNFR2 expression is increased in these Treg cells by Affymetrix chip analysis which was confirmed by monoclonal antibody staining in both hepatocellular carcinoma (HCC) and colorectal cancer (CRC) patients and murine models. Correspondingly, increased levels of TNF-α in both tissue and serum were also demonstrated. Interestingly, TNF-α could not only expand effector Treg cells through TNFR2 signaling, but also enhanced their suppressive activity against antitumor immunity of CD8+ T cells. Furthermore, targeting TNFR2 signaling with a TNF-α inhibitor could selectively reduce rapid resurgence of effector Treg cells after cyclophosphamide-induced lymphodepletion and markedly inhibit the growth of established tumors. Herein, we propose a novel mechanism in which TNF-α could promote tumor-associated effector Treg cell expansion and suggest a new cancer immunotherapy strategy using TNF-α inhibitors to reduce effector Treg cells expansion after cyclophosphamide-induced lymphodepletion. PMID:26451304

  14. Regulatory Oversight of Cell and Gene Therapy Products in Canada.

    PubMed

    Ridgway, Anthony; Agbanyo, Francisca; Wang, Jian; Rosu-Myles, Michael

    2015-01-01

    Health Canada regulates gene therapy products and many cell therapy products as biological drugs under the Canadian Food and Drugs Act and its attendant regulations. Cellular products that meet certain criteria, including minimal manipulation and homologous use, may be subjected to a standards-based approach under the Safety of Human Cells, Tissues and Organs for Transplantation Regulations. The manufacture and clinical testing of cell and gene therapy products (CGTPs) presents many challenges beyond those for protein biologics. Cells cannot be subjected to pathogen removal or inactivation procedures and must frequently be administered shortly after final formulation. Viral vector design and manufacturing control are critically important to overall product quality and linked to safety and efficacy in patients through concerns such as replication competence, vector integration, and vector shedding. In addition, for many CGTPs, the value of nonclinical studies is largely limited to providing proof of concept, and the first meaningful data relating to appropriate dosing, safety parameters, and validity of surrogate or true determinants of efficacy must come from carefully designed clinical trials in patients. Addressing these numerous challenges requires application of various risk mitigation strategies and meeting regulatory expectations specifically adapted to the product types. Regulatory cooperation and harmonisation at an international level are essential for progress in the development and commercialisation of these products. However, particularly in the area of cell therapy, new regulatory paradigms may be needed to harness the benefits of clinical progress in situations where the resources and motivation to pursue a typical drug product approval pathway may be lacking. PMID:26374212

  15. Regulatory T cells vs Th17: differentiation of Th17 versus Treg, are the mutually exclusive?

    PubMed Central

    Zheng, Song Guo

    2013-01-01

    Naive CD4+ cells differentiate into T helper (Th1, Th2, Th9, Th17) and regulatory T (Treg) cells to execute their immunologic function. Whereas TGF-β suppresses Th1 and Th2 cell differentiation, this cytokine promotes Th9, Th17 and Foxp3+ regulatory T cells depending upon the presence of other cytokines. IL-6 promotes Th17, but suppresses regulatory T cell differentiation. Moreover, natural but not TGF-β-induced regulatory T cells convert into Th17 cells in the inflammatory milieu. Here an update of T cell differentiation and conversion, as well as underlying mechanisms are given. PMID:23885327

  16. Alterations in regulatory T-cells: rediscovered pathways in immunotoxicology.

    PubMed

    Corsini, Emanuela; Oukka, Mohamed; Pieters, Raymond; Kerkvliet, Nancy I; Ponce, Rafael; Germolec, Dori R

    2011-01-01

    In addition to the effector T-cells subsets, T-cells can also differentiate into cells that play a suppressive or regulatory role in adaptive immune responses. The cell types currently identified as regulatory T-cells (T(regs)) include natural or thymic-derived T(regs), T-cells which express Foxp3(+)CD25(+)CD4(+) and can suppress immune responses to autoreactive T-cells, as well as inducible T(regs), that are generated from naïve T-cells in the periphery after interaction with antigens presented by dendritic cells. Inducible T(regs) include T(H)3 cells, T(r)1 cells, and Foxp3(+)-inducible T(regs). T(regs) have been shown to be critical in the maintenance of immune responses and T-cell homeostasis. These cells play an important role in suppressing responses to self-antigens and in controlling inappropriate responses to non-self-antigens, such as commensal bacteria or food in the gut. For example, depletion of CD4(+)CD25(+) T(regs) from mice resulted in the development of multi-organ autoimmune diseases. CD4(+)CD25(+) T(regs) and/or IL-10-producing T(r)1 cells are capable of suppressing or attenuating T(H)2 responses to allergens. Moreover, adoptive transfer of CD4(+)CD25(+) T(regs) from healthy to diseased animals resulted in the prevention or cure of certain autoimmune diseases, and was able to induce transplantation tolerance. Clinical improvement seen after allergen immunotherapy for allergic diseases such as rhinitis and asthma is associated with the induction of IL-10- and TGFβ-producing T(r)1 cells as well as FoxP3-expressing IL-10 T-cells, with resulting suppression of the T(H)2 cytokine milieu. Activation, expansion, or suppression of CD4(+)CD25(+) T(regs) in vivo by xenobiotics, including drugs, may therefore represent a relevant mechanism underlying immunotoxicity, including immunosuppression, allergic asthma, and autoimmune diseases. PMID:21848365

  17. Regulatory T cells in atherosclerosis: critical immune regulatory function and therapeutic potential.

    PubMed

    Spitz, Charlotte; Winkels, Holger; Bürger, Christina; Weber, Christian; Lutgens, Esther; Hansson, Göran K; Gerdes, Norbert

    2016-03-01

    Atherosclerosis is a chronic inflammatory disease that is mediated by innate and adaptive immune responses. The disease is characterized by sub-endothelial accumulation and modification of lipids in the artery wall triggering an inflammatory reaction which promotes lesion progression and eventual plaque rupture, thrombus formation, and the respective clinical sequelae such as myocardial infarction or stroke. During the past decade, T-cell-mediated immune responses, especially control of pro-inflammatory signals by regulatory T cells (Tregs), have increasingly attracted the interest of experimental and clinical researchers. By suppression of T cell proliferation and secretion of anti-inflammatory cytokines, such as interleukin-10 (IL-10) and transforming growth factor-β, Tregs exert their atheroprotective properties. Atherosclerosis-prone, hyperlipidemic mice harbor systemically less Tregs compared to wild-type mice, suggesting an imbalance of immune cells which affects local and systemic inflammatory and potentially metabolic processes leading to atherogenesis. Restoring or increasing Treg frequency and enhancing their suppressive capacity by various modulations may pose a promising approach for treating inflammatory conditions such as cardiovascular diseases. In this review, we briefly summarize the immunological basics of atherosclerosis and introduce the role and contribution of different subsets of T cells. We then discuss experimental data and current knowledge pertaining to Tregs in atherosclerosis and perspectives on manipulating the adaptive immune system to alleviate atherosclerosis and cardiovascular disease. PMID:26518635

  18. Adipose-derived stem cells ameliorate allergic airway inflammation by inducing regulatory T cells in a mouse model of asthma.

    PubMed

    Cho, Kyu-Sup; Park, Mi-Kyung; Kang, Shin-Ae; Park, Hee-Young; Hong, Sung-Lyong; Park, Hye-Kyung; Yu, Hak-Sun; Roh, Hwan-Jung

    2014-01-01

    Although several studies have demonstrated that mesenchymal stem cells derived from adipose tissue (ASCs) can ameliorate allergic airway inflammation, the immunomodulatory mechanism of ASCs remains unclear. In this study, we investigated whether regulatory T cells (Tregs) induction is a potential mechanism in immunomodulatory effects of ASCs on allergic airway disease and how these induced Tregs orchestrate allergic inflammation. Intravenous administration of ASCs significantly reduced allergic symptoms and inhibited eosinophilic inflammation. Airway hyperresponsiveness, total immune cell and eosinophils in the bronchoalveolar lavage fluid, mucus production, and serum allergen-specific IgE and IgG1 were significantly reduced after ASCs administration. ASCs significantly inhibited Th2 cytokines (IL-4, IL-5, and IL-13) and enhanced Th1 cytokine (IFN-γ) and regulatory cytokines (IL-10 and TGF-β) in the bronchoalveolar lavage fluid and lung draining lymph nodes. Furthermore, levels of IDO, TGF-β, and PGE2 were significantly increased after ASCs administration. Interestingly, this upregulation was accompanied by increased Treg populations. In conclusion, ASCs ameliorated allergic airway inflammation and improved lung function through the induction of Treg expansion. The induction of Treg by ASCs involves the secretion of soluble factors such as IDO, TGF-β, and PGE2 and Treg might be involved in the downregulation of Th2 cytokines and upregulation of Th1 cytokines production. PMID:25246732

  19. Regulatory T-Cell-Associated Cytokines in Systemic Lupus Erythematosus

    PubMed Central

    Okamoto, Akiko; Fujio, Keishi; Okamura, Tomohisa; Yamamoto, Kazuhiko

    2011-01-01

    Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production, complement activation, and immune complex deposition, resulting in tissue and organ damage. An understanding of the mechanisms responsible for homeostatic control of inflammation, which involve both innate and adoptive immune responses, will enable the development of novel therapies for SLE. Regulatory T cells (Treg) play critical roles in the induction of peripheral tolerance to self- and foreign antigens. Naturally occurring CD4+CD25+ Treg, which characteristically express the transcription factor forkhead box protein P3 (Foxp3), have been intensively studied because their deficiency abrogates self-tolerance and causes autoimmune disease. Moreover, regulatory cytokines such as interleukin-10 (IL-10) also play a central role in controlling inflammatory processes. This paper focuses on Tregs and Treg-associated cytokines which might regulate the pathogenesis of SLE and, hence, have clinical applications. PMID:22219657

  20. Suppression of HIV Replication by CD8+ Regulatory T-Cells in Elite Controllers

    PubMed Central

    Lu, Wei; Chen, Song; Lai, Chunhui; Lai, Mingyue; Fang, Hua; Dao, Hong; Kang, Jun; Fan, Jianhua; Guo, Weizhong; Fu, Linchun; Andrieu, Jean-Marie

    2016-01-01

    We previously demonstrated in the Chinese macaque model that an oral vaccine made of inactivated SIV and Lactobacillus plantarum induced CD8+ regulatory T-cells, which suppressed the activation of SIV+CD4+ T-cells, prevented SIV replication, and protected macaques from SIV challenges. Here, we sought whether a similar population of CD8+ T-regs would induce the suppression of HIV replication in elite controllers (ECs), a small population (3‰) of HIV-infected patients with undetectable HIV replication. For that purpose, we investigated the in vitro antiviral activity of fresh CD8+ T-cells on HIV-infected CD4+ T-cells taken from 10 ECs. The 10 ECs had a classical genomic profile: all of them carried the KIR3DL1 gene and 9 carried at least 1 allele of HLA-B:Bw4-80Ile (i.e., with an isoleucine residue at position 80). In the nine HLA-B:Bw4-80Ile-positive patients, we demonstrated a strong viral suppression by KIR3DL1-expressing CD8+ T-cells that required cell-to-cell contact to switch off the activation signals in infected CD4+ T-cells. KIR3DL1-expressing CD8+ T-cells withdrawal and KIR3DL1 neutralization by a specific anti-killer cell immunoglobulin-like receptor (KIR) antibody inhibited the suppression of viral replication. Our findings provide the first evidence for an instrumental role of KIR-expressing CD8+ regulatory T-cells in the natural control of HIV-1 infection. PMID:27148256

  1. Adoptive therapy with redirected primary regulatory T cells results in antigen-specific suppression of arthritis.

    PubMed

    Wright, Graham P; Notley, Clare A; Xue, Shao-An; Bendle, Gavin M; Holler, Angelika; Schumacher, Ton N; Ehrenstein, Michael R; Stauss, Hans J

    2009-11-10

    Regulatory T cells (Tregs) can suppress a wide range of immune cells, making them an ideal candidate for the treatment of autoimmunity. The potential clinical translation of targeted therapy with antigen-specific Tregs is hampered by the difficulties of isolating rare specificities from the natural polyclonal T cell repertoire. Moreover, the initiating antigen is often unknown in autoimmune disease. Here we tested the ability of antigen-specific Tregs generated by retroviral gene transfer to ameliorate arthritis through linked suppression and therefore without cognate recognition of the disease-initiating antigen. We explored two distinct strategies: T cell receptor (TCR) gene transfer into purified CD4+CD25+ T cells was used to redirect the specificity of naturally occurring Tregs; and co-transfer of FoxP3 and TCR genes served to convert conventional CD4(+) T cells into antigen-specific regulators. Following adoptive transfer into recipient mice, the gene-modified T cells engrafted efficiently and retained TCR and FoxP3 expression. Using an established arthritis model, we demonstrate antigen-driven accumulation of the gene modified T cells at the site of joint inflammation, which resulted in a local reduction in the number of inflammatory Th17 cells and a significant decrease in arthritic bone destruction. Together, we describe a robust strategy to rapidly generate antigen-specific regulatory T cells capable of highly targeted inhibition of tissue damage in the absence of systemic immune suppression. This opens the possibility to target Tregs to tissue-specific antigens for the treatment of autoimmune tissue damage without the knowledge of the disease-causing autoantigens recognized by pathogenic T cells. PMID:19884493

  2. Positive regulatory domain I binding factor 1 silences class II transactivator expression in multiple myeloma cells.

    PubMed

    Ghosh, N; Gyory, I; Wright, G; Wood, J; Wright, K L

    2001-05-01

    The major histocompatibility complex (MHC) class II transactivator (CIITA) acts as a master switch to activate expression of the genes required for MHC-II antigen presentation. During B-cell to plasma cell differentiation, MHC-II expression is actively silenced, but the mechanism has been unknown. In plasma cell tumors such as multiple myeloma the repression of MHC-II is associated with the loss of CIITA. We have identified that positive regulatory domain I binding factor 1 (PRDI-BF1), a transcriptional repressor, inhibits CIITA expression in multiple myeloma cell lines. Repression of CIITA depends on the DNA binding activity of PRDI-BF1 and its specific binding site in the CIITA promoter. Deletion of a histone deacetylase recruitment domain in PRDI-BF1 does not inhibit repression of CIITA nor does blocking histone deacetylase activity. This is in contrast to PRDI-BF1 repression of the c-myc promoter. Repression of CIITA requires either the N-terminal acidic and conserved PR motif or the proline-rich domain. PRDI-BF1 has been shown to be a key regulator of B-cell and macrophage differentiation. These findings now indicate that PRDI-BF1 has at least two mechanisms of repression whose function is dependent on the nature of the target promoter. Importantly, PRDI-BF1 is defined as the key molecule in silencing CIITA and thus MHC-II in multiple myeloma cells. PMID:11279146

  3. Notch and TGFβ form a positive regulatory loop and regulate EMT in epithelial ovarian cancer cells.

    PubMed

    Zhou, Jiesi; Jain, Saket; Azad, Abul K; Xu, Xia; Yu, Hai Chuan; Xu, Zhihua; Godbout, Roseline; Fu, YangXin

    2016-08-01

    Epithelial-mesenchymal transition (EMT) plays a critical role in the progression of epithelial ovarian cancer (EOC). However, the mechanisms that regulate EMT in EOC are not fully understood. Here, we report that activation of Notch1 induces EMT in EOC cells as evidenced by downregulation of E-cadherin and cytokeratins, upregulation of Slug and Snail, as well as morphological changes. Interestingly, activation of Notch1 increases TGFβ/Smad signaling by upregulating the expression of TGFβ and TGFβ type 1 receptor. Time course experiments demonstrate that inhibition of Notch by DAPT (a γ-secretase inhibitor) decreases TGFβ-induced phosphorylation of receptor Smads at late, but not at early, timepoints. These results suggest that Notch activation plays a role in sustaining TGFβ/Smad signaling in EOC cells. Furthermore, inhibition of Notch by DAPT decreases TGFβ induction of Slug and repression of E-cadherin and knockdown of Notch1 decreases TGFβ-induced repression of E-cadherin, indicating that Notch is required, at least in part, for TGFβ-induced EMT in EOC cells. On the other hand, TGFβ treatment increases the expression of Notch ligand Jagged1 and Notch target gene HES1 in EOC cells. Functionally, the combination of Notch1 activation and TGFβ treatment is more potent in promoting motility and migration of EOC cells than either stimulation alone. Taken together, our results indicate that Notch and TGFβ form a reciprocal positive regulatory loop and cooperatively regulate EMT and promote EOC cell motility and migration. PMID:27075926

  4. Foxp3 expressing regulatory T-cells in allergic disease.

    PubMed

    Nouri-Aria, Kayhan T

    2009-01-01

    Allergic diseases such as asthma, rhinitis and eczema are increasing in prevalence worldwide, in particular in industrialised countries affecting up to 20% of the population. Regulatory T-cells (Tregs) have been shown to be critical in T-cell homeostasis and in the maintenance of immune responses, such as prevention of autoimmunity and hampering allergic diseases. The so-called 'natural' CD4+CD25+ Tregs and/or IL-10-producing Tr1 cells have been shown to be responsible for the protection of immune tolerance and intact immune reactions following exposure to allergens such as aeroallergens or food allergens. In this regard, both cell-cell contact (through membrane bound TGF-beta or via suppressive molecules such as CLTA-4) and soluble cytokine-(TGF-beta and IL-10) dependent mechanisms have been shown to contribute to the ability of Tregs to operate effectively. The transcription factor Foxp3, a member of the forkhead-winged helix family, appears to be critical in the suppressive abilities of regulatory T-cells. Adoptive transfer of CD4+CD25+ Tregs from healthy to diseased animals corroborated and provided further evidence of the vital role of these populations in the prevention or cure of certain autoimmune conditions. Clinical improvement seen after allergen immunotherapy for allergic diseases such as rhinitis and asthma has also been associated with the induction of IL-10 and TGF-beta producing Trl cells as well as Foxp3 expressing CD4+CD25+ T-cells, resulting in the suppression ofTh2 cytokine milieu. Activation and expansion ofantigen-specific CD4+CD25+ Tregs in vivo using adjuvants such as IL-10 or pharmacological agents such as low dose steroids or vitamin D3 could represent novel approaches to induce antigen-specific tolerance in immune-mediated conditions such as allergic asthma, autoimmune disease and the rejection of transplanted organs in man. PMID:20429425

  5. Downregulation of key regulatory proteins in androgen dependent prostate tumor cells by oncolytic reovirus.

    PubMed

    Gupta-Saraf, Pooja; Meseke, Tyler; Miller, Cathy L

    2015-11-01

    As prostate tumor cell growth depends on hormones, androgen ablation is an effective therapy for prostate cancer (PCa). However, progression of PCa cells to androgen independent growth (castrate resistant prostate cancer, CRPC) results in relapse and mortality. Hypoxia, a microenvironment of low oxygen that modifies the activity of PCa regulatory proteins including the androgen receptor (AR), plays a critical role in progression to CRPC. Therapies targeting hypoxia and the AR may lengthen the time to CRPC progression thereby increasing survival time of PCa patients. Mammalian Orthoreovirus (MRV) has shown promise for the treatment of prostate tumors in vitro and in vivo. In this study, we found that MRV infection induces downregulation of proteins implicated in CRPC progression, interferes with hypoxia-induced AR activity, and induces apoptosis in androgen dependent cells. This suggests MRV possesses traits that could be exploited to create novel therapies for the inhibition of progression to CRPC. PMID:26264969

  6. A Wave of Regulatory T Cells into Neonatal Skin Mediates Tolerance to Commensal Microbes.

    PubMed

    Scharschmidt, Tiffany C; Vasquez, Kimberly S; Truong, Hong-An; Gearty, Sofia V; Pauli, Mariela L; Nosbaum, Audrey; Gratz, Iris K; Otto, Michael; Moon, James J; Liese, Jan; Abbas, Abul K; Fischbach, Michael A; Rosenblum, Michael D

    2015-11-17

    The skin is a site of constant dialog between the immune system and commensal bacteria. However, the molecular mechanisms that allow us to tolerate the presence of skin commensals without eliciting destructive inflammation are unknown. Using a model system to study the antigen-specific response to S. epidermidis, we demonstrated that skin colonization during a defined period of neonatal life was required for establishing immune tolerance to commensal microbes. This crucial window was characterized by an abrupt influx of highly activated regulatory T (Treg) cells into neonatal skin. Selective inhibition of this Treg cell wave completely abrogated tolerance. Thus, the host-commensal relationship in the skin relied on a unique Treg cell population that mediated tolerance to bacterial antigens during a defined developmental window. This suggests that the cutaneous microbiome composition in neonatal life is crucial in shaping adaptive immune responses to commensals, and disrupting these interactions might have enduring health implications. PMID:26588783

  7. PKC-Theta in Regulatory and Effector T-cell Functions

    PubMed Central

    Brezar, Vedran; Tu, Wen Juan; Seddiki, Nabila

    2015-01-01

    One of the major goals in immunology research is to understand the regulatory mechanisms that underpin the rapid switch on/off of robust and efficient effector (Teffs) or regulatory (Tregs) T-cell responses. Understanding the molecular mechanisms underlying the regulation of such responses is critical for the development of effective therapies. T-cell activation involves the engagement of T-cell receptor and co-stimulatory signals, but the subsequent recruitment of serine/threonine-specific protein Kinase C-theta (PKC-θ) to the immunological synapse (IS) is instrumental for the formation of signaling complexes, which ultimately lead to a transcriptional network in T cells. Recent studies demonstrated that major differences between Teffs and Tregs occurred at the IS where its formation induces altered signaling pathways in Tregs. These pathways are characterized by reduced recruitment of PKC-θ, suggesting that PKC-θ inhibits Tregs suppressive function in a negative feedback loop. As the balance of Teffs and Tregs has been shown to be central in several diseases, it was not surprising that some studies revealed that PKC-θ plays a major role in the regulation of this balance. This review will examine recent knowledge on the role of PKC-θ in T-cell transcriptional responses and how this protein can impact on the function of both Tregs and Teffs. PMID:26528291

  8. The Effect of Traditional Chinese Formula Danchaiheji on the Differentiation of Regulatory Dendritic Cells

    PubMed Central

    Wang, Xiaodong; Tong, Jingzhi; Li, Keqiu; Jing, Yaqing

    2016-01-01

    Recently, regulatory dendritic cells (DCregs), a newly described dendritic cell subset with potent immunomodulatory function, have attracted increased attention for their utility in treating immune response-related diseases, such as graft-versus-host disease, hypersensitivity, and autoimmune diseases. Danchaiheji (DCHJ) is a traditional Chinese formula that has been used for many years in the clinic. However, whether DCHJ can program dendritic cells towards a regulatory phenotype and the underlying mechanism behind this process remain unknown. Herein, we investigate the effects of traditional Chinese DCHJ on DCregs differentiation and a mouse model of skin transplantation. The current study demonstrates that DCHJ can induce dendritic cells to differentiate into DCregs, which are represented by high CD11b and low CD86 and HLA-DR expression as well as the secretion of IL-10 and TGF-β. In addition, DCHJ inhibited DC migration and T cell proliferation, which correlated with increased IDO expression. Furthermore, DCHJ significantly prolonged skin graft survival time in a mouse model of skin transplantation without any liver or kidney toxicity. The traditional Chinese formula DCHJ has the potential to be a potent immunosuppressive agent with high efficiency and nontoxicity. PMID:27525028

  9. Geranylated flavanone tomentodiplacone B inhibits proliferation of human monocytic leukaemia (THP-1) cells

    PubMed Central

    Kollár, Peter; Bárta, Tomáš; Závalová, Veronika; Šmejkal, Karel; Hampl, Aleš

    2011-01-01

    BACKGROUND AND PURPOSE Paulownia tomentosa is a rich source of geranylated flavanones, some of which we have previously shown to have cytotoxic activity. To identify members of this class of compounds with cytostatic effects, we assessed the effects of the geranylated flavanone tomentodiplacone B (TOM B) on cell cycle progression and cell cycle regulatory pathways of THP-1 human monocytic leukaemia cells. EXPERIMENTAL APPROACH Cell viability was measured by dye exclusion and proliferation by WST-1 assays; cell cycle was monitored by flow cytometry. Regulatory proteins were assessed by immunoprecipitation and kinase assays, and Western blotting. KEY RESULTS Tomentodiplacone B had no effect during the first 24 h of cell growth at concentrations between 1 and 2.5 µM, but inhibited cell growth in a dose-dependent manner at concentrations of 5 µM or higher. Growth inhibition during the first 24 h of exposure to TOM B was not accompanied by cytotoxicity as cells were accumulated in G1 phase dose-dependently. This G1 phase accumulation was associated with down-regulation of cyclin-dependent kinase 2 activity and also protein levels of cyclins E1 and A2. However, key stress-related molecules (γ-H2AX, p53 and p21) were not induced, suggesting that TOM B acts by directly inhibiting the cyclin-dependent kinase 2 signalling pathway rather than initiating DNA damage or cellular stress. CONCLUSIONS AND IMPLICATIONS Our study provides the first evidence that TOM B directly inhibits proliferation of human monocytic leukaemia cells, and thus is a potential anticancer agent, preventing leukaemia cells from progressing from G1 phase into DNA synthesis. PMID:21175584

  10. Natural and induced T regulatory cells in cancer.

    PubMed

    Adeegbe, Dennis O; Nishikawa, Hiroyoshi

    2013-01-01

    CD4+Foxp3+ T regulatory (Treg) cells control many facets of immune responses ranging from autoimmune diseases, to inflammatory conditions, and cancer in an attempt to maintain immune homeostasis. Natural Treg (nTreg) cells develop in the thymus and constitute a critical arm of active mechanisms of peripheral tolerance particularly to self antigens. A growing body of knowledge now supports the existence of induced Treg (iTreg) cells which may derive from a population of conventional CD4+ T cells. The fork-head transcription factor (Foxp3) typically is expressed by natural CD4+ Treg cells, and thus serves as a marker to definitively identify these cells. On the contrary, there is less consensus on what constitutes iTreg cells as their precise definition has been somewhat elusive. This is in part due to their distinct phenotypes which are shaped by exposure to certain inflammatory or "assault" signals stemming from the underlying immune disorder. The "policing" activity of Treg cells tends to be uni-directional in several pathological conditions. On one end of the spectrum, Treg cell suppressive activity is beneficial by curtailing T cell response against self-antigens and allergens thus preventing autoimmune diseases and allergies. On the other end however, their inhibitory roles in limiting immune response against pseudo-self antigens as in tumors often culminates into negative outcomes. In this review, we focus on this latter aspect of Treg cell immunobiology by highlighting the involvement of nTreg cells in various animal models and human tumors. We further discuss iTreg cells, relationship with their natural counterpart, and potential co-operation between the two in modulating immune response against tumors. Lastly, we discuss studies focusing on these cells as targets for improving anti-tumor immunity. PMID:23874336

  11. Functional Improvement of Regulatory T Cells from Rheumatoid Arthritis Subjects Induced by Capsular Polysaccharide Glucuronoxylomannogalactan

    PubMed Central

    Alunno, Alessia; Bartoloni Bocci, Elena; Perito, Stefano; Chow, Siu-Kei; Cenci, Elio; Casadevall, Arturo; Gerli, Roberto; Vecchiarelli, Anna

    2014-01-01

    Objective Regulatory T cells (Treg) play a critical role in the prevention of autoimmunity, and the suppressive activity of these cells is impaired in rheumatoid arthritis (RA). The aim of the present study was to investigate function and properties of Treg of RA patients in response to purified polysaccharide glucuronoxylomannogalactan (GXMGal). Methods Flow cytometry and western blot analysis were used to investigate the frequency, function and properties of Treg cells. Results GXMGal was able to: i) induce strong increase of FOXP3 on CD4+ T cells without affecting the number of CD4+CD25+FOXP3+ Treg cells with parallel increase in the percentage of non-conventional CD4+CD25−FOXP3+ Treg cells; ii) increase intracellular levels of TGF-β1 in CD4+CD25−FOXP3+ Treg cells and of IL-10 in both CD4+CD25+FOXP3+ and CD4+CD25−FOXP3+ Treg cells; iii) enhance the suppressive activity of CD4+CD25+FOXP3+ and CD4+CD25−FOXP3+ Treg cells in terms of inhibition of effector T cell activity and increased secretion of IL-10; iv) decrease Th1 response as demonstrated by inhibition of T-bet activation and down-regulation of IFN-γ and IL-12p70 production; v) decrease Th17 differentiation by down-regulating pSTAT3 activation and IL-17A, IL-23, IL-21, IL-22 and IL-6 production. Conclusion These data show that GXMGal improves Treg functions and increases the number and function of CD4+CD25−FOXP3+ Treg cells of RA patients. It is suggested that GXMGal may be potentially useful for restoring impaired Treg functions in autoimmune disorders and for developing Treg cell-based strategies for the treatment of these diseases. PMID:25338013

  12. Hepatic Stellate Cells Inhibit T Cells through Active TGF-β1 from a Cell Surface-Bound Latent TGF-β1/GARP Complex.

    PubMed

    Li, Yan; Kim, Byung-Gyu; Qian, Shiguang; Letterio, John J; Fung, John J; Lu, Lina; Lin, Feng

    2015-09-15

    Hepatic stellate cells (HSCs) inhibit T cells, a process that could help the liver to maintain its immunoprivileged status. HSCs secrete latent TGF-β1, but the detailed mechanisms by which latent TGF-β1 is activated and whether it plays any role in HSC-mediated T cell suppression remain unclear. Glycoprotein A repetitions predominant (GARP) is a surface marker of activated regulatory T cells. GARP binds latent TGF-β1 for its activation, which is critical for regulatory T cells to suppress effector T cells; however, it is still unclear whether GARP is present on HSCs and whether it has any impact on HSC function. In this study, we found that TGF-β1(+/-) HSCs, which produce reduced levels of TGF-β1, showed decreased potency in inhibiting T cells. We also found that pharmaceutical or genetic inhibition of the TGF-β1 signaling pathway reduced the T cell-inhibiting activity of HSCs. Additionally, using isolated primary HSCs, we demonstrated that GARP was constitutively expressed on HSCs. Blocking GARP function or knocking down GARP expression significantly impaired the potency of HSCs to suppress the proliferation of and IFN-γ production from activated T cells, suggesting that GARP is important for HSCs to inhibit T cells. These results demonstrate the unexpected presence of GARP on HSCs and its significance in regard to the ability of HSCs to activate latent TGF-β1 and thereby inhibit T cells. Our study reveals a new mechanism for HSC-mediated immune regulation and potentially for other conditions, such as liver fibrosis, that involve HSC-secreted TGF-β1. PMID:26246140

  13. Inhibition of selective signaling events in natural killer cells recognizing major histocompatibility complex class I.

    PubMed Central

    Kaufman, D S; Schoon, R A; Robertson, M J; Leibson, P J

    1995-01-01

    Many studies have characterized the transmembrane signaling events initiated after T-cell antigen receptor recognition of major histocompatibility complex (MHC)-bound peptides. Yet, little is known about signal transduction from a set of MHC class I recognizing receptors on natural killer (NK) cells whose ligation dramatically inhibits NK cell-mediated killing. In this study we evaluated the influence of MHC recognition on the proximal signaling events in NK cells binding tumor targets. We utilized two experimental models where NK cell-mediated cytotoxicity was fully inhibited by the recognition of specific MHC class I molecules. NK cell binding to either class I-deficient or class I-transfected target cells initiated rapid protein tyrosine kinase activation. In contrast, whereas NK cell binding to class I-deficient targets led to inositol phosphate release and increased intracellular free calcium ([Ca2+]i), NK recognition of class I-bearing targets did not induce the activation of these phospholipase C-dependent signaling events. The recognition of class I by NK cells clearly had a negative regulatory effect since blocking this interaction using anti-class I F(ab')2 fragments increased inositol 1,4,5-trisphosphate release and [Ca2+]i and increased the lysis of the targets. These results suggest that one of the mechanisms by which NK cell recognition of specific MHC class I molecules can block the development of cell-mediated cytotoxicity is by inhibiting specific critical signaling events. Images Fig. 2 Fig. 4 PMID:7604018

  14. Inhibition of protein kinase C catalytic activity by additional regions within the human protein kinase Calpha-regulatory domain lying outside of the pseudosubstrate sequence.

    PubMed

    Kirwan, Angie F; Bibby, Ashley C; Mvilongo, Thierry; Riedel, Heimo; Burke, Thomas; Millis, Sherri Z; Parissenti, Amadeo M

    2003-07-15

    The N-terminal pseudosubstrate site within the protein kinase Calpha (PKCalpha)-regulatory domain has long been regarded as the major determinant for autoinhibition of catalytic domain activity. Previously, we observed that the PKC-inhibitory capacity of the human PKCalpha-regulatory domain was only reduced partially on removal of the pseudosubstrate sequence [Parissenti, Kirwan, Kim, Colantonio and Schimmer (1998) J. Biol. Chem. 273, 8940-8945]. This finding suggested that one or more additional region(s) contributes to the inhibition of catalytic domain activity. To assess this hypothesis, we first examined the PKC-inhibitory capacity of a smaller fragment of the PKCalpha-regulatory domain consisting of the C1a, C1b and V2 regions [GST-Ralpha(39-177): this protein contained the full regulatory domain of human PKCalpha fused to glutathione S-transferase (GST), but lacked amino acids 1-38 (including the pseudosubstrate sequence) and amino acids 178-270 (including the C2 region)]. GST-Ralpha(39-177) significantly inhibited PKC in a phorbol-independent manner and could not bind the peptide substrate used in our assays. These results suggested that a region within C1/V2 directly inhibits catalytic domain activity. Providing further in vivo support for this hypothesis, we found that expression of N-terminally truncated pseudosubstrate-less bovine PKCalpha holoenzymes in yeast was capable of inhibiting cell growth in a phorbol-dependent manner. This suggested that additional autoinhibitory force(s) remained within the truncated holoenzymes that could be relieved by phorbol ester. Using tandem PCR-mediated mutagenesis, we observed that mutation of amino acids 33-86 within GST-Ralpha(39-177) dramatically reduced its PKC-inhibitory capacity when protamine was used as substrate. Mutagenesis of a broad range of sequences within C2 (amino acids 159-242) also significantly reduced PKC-inhibitory capacity. Taken together, these observations support strongly the existence of

  15. Mechanisms of suberoylanilide hydroxamic acid inhibition of mammary cell growth

    PubMed Central

    Said, Thenaa K; Moraes, Ricardo CB; Sinha, Raghu; Medina, Daniel

    2001-01-01

    The mechanism of suberoylanilide hydroxamic acid in cell growth inhibition involved induction of pRb-2/p130 interaction and nuclear translocation with E2F-4, followed by significant repression in E2F-1 and PCNA nuclear levels, which led to inhibition in DNA synthesis in mammary epithelial cell lines. PMID:11250759

  16. SHARPIN controls the development of regulatory T cells.

    PubMed

    Redecke, Vanessa; Chaturvedi, Vandana; Kuriakose, Jeeba; Häcker, Hans

    2016-06-01

    SHARPIN is an essential component of the linear ubiquitin chain assembly complex (LUBAC) complex that controls signalling pathways of various receptors, including the tumour necrosis factor receptor (TNFR), Toll-like receptor (TLR) and antigen receptor, in part by synthesis of linear, non-degrading ubiquitin chains. Consistent with SHARPIN's function in different receptor pathways, the phenotype of SHARPIN-deficient mice is complex, including the development of inflammatory systemic and skin diseases, the latter of which depend on TNFR signal transduction. Given the established function of SHARPIN in primary and malignant B cells, we hypothesized that SHARPIN might also regulate T-cell receptor (TCR) signalling and thereby control T-cell biology. Here, we focus primarily on the role of SHARPIN in T cells, specifically regulatory T (Treg) cells. We found that SHARPIN-deficient (Sharpin(cpdm/cpdm) ) mice have significantly reduced numbers of FOXP3(+) Treg cells in lymphoid organs and the peripheral blood. Competitive reconstitution of irradiated mice with mixed bone marrow from wild-type and SHARPIN-deficient mice revealed an overall reduced thymus population with SHARPIN-deficient cells with almost complete loss of thymic Treg development. Consistent with this cell-intrinsic function of SHARPIN in Treg development, TCR stimulation of SHARPIN-deficient thymocytes revealed reduced activation of nuclear factor-κB and c-Jun N-terminal kinase, establishing a function of SHARPIN in TCR signalling, which may explain the defective Treg development. In turn, in vitro generation and suppressive activity of mature SHARPIN-deficient Treg cells were comparable to wild-type cells, suggesting that maturation, but not function, of SHARPIN-deficient Treg cells is impaired. Taken together, these findings show that SHARPIN controls TCR signalling and is required for efficient generation of Treg cells in vivo, whereas the inhibitory function of mature Treg cells appears to be

  17. Orchestration of plasma cell differentiation by Bach2 and its gene regulatory network.

    PubMed

    Igarashi, Kazuhiko; Ochiai, Kyoko; Itoh-Nakadai, Ari; Muto, Akihiko

    2014-09-01

    Bach2 is a basic region-leucine zipper (bZip) transcription factor that forms heterodimers with small Maf oncoproteins and binds to target genes, thus repressing their expression. Bach2 is required for class switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes in activated B cells. Bach2 represses the expression of Prdm1 encoding Blimp-1 repressor and thereby inhibits terminal differentiation of B cells to plasma cells. This causes a delay in the induction of Prdm1, thereby securing a time window for the expression of Aicda encoding activation-induced cytidine deaminase (AID) required for both CSR and SHM. Based on the characteristics of a gene regulatory network (GRN) involving Bach2 and Prdm1 and its dynamics, a 'delay-driven diversity' model was introduced to explain the responses of activated B cells. Bach2 is also required for the proper differentiation and function of peripheral T cells. In the absence of Bach2, CD4(+) T cells show increased differentiation to effector cells producing higher levels of Th2-related cytokines, such as IL-4 and IL-10, and a reduction in the generation of regulatory T cells. Bach2 represses many genes in T cells, including Prdm1, suggesting that the Bach2-Prdm1 pathway is also important in maintaining the homeostasis of T cells. Furthermore, Bach2 is essential for the function of alveolar macrophages. Therefore, Bach2 orchestrates both acquired and innate immunity at multiple points. Its connection with disease is also reviewed in this report. PMID:25123280

  18. Transcriptional Regulatory Network for the Development of Innate Lymphoid Cells

    PubMed Central

    Zhong, Chao; Zhu, Jinfang

    2015-01-01

    Recent studies on innate lymphoid cells (ILCs) have expanded our knowledge about the innate arm of the immune system. Helper-like ILCs share both the “innate” feature of conventional natural killer (cNK) cells and the “helper” feature of CD4+ T helper (Th) cells. With this combination, helper-like ILCs are capable of initiating early immune responses similar to cNK cells, but via secretion of a set of effector cytokines similar to those produced by Th cells. Although many studies have revealed the functional similarity between helper-like ILCs and Th cells, some aspects of ILCs including the development of this lineage remain elusive. It is intriguing that the majority of transcription factors involved in multiple stages of T cell development, differentiation, and function also play critical roles during ILC development. Regulators such as Id2, GATA-3, Nfil3, TOX, and TCF-1 are expressed and function at various stages of ILC development. In this review, we will summarize the expression and functions of these transcription factors shared by ILCs and Th cells. We will also propose a complex transcriptional regulatory network for the lineage commitment of ILCs. PMID:26379372

  19. Parameterizing cell-to-cell regulatory heterogeneities via stochastic transcriptional profiles

    PubMed Central

    Bajikar, Sameer S.; Fuchs, Christiane; Roller, Andreas; Theis, Fabian J.; Janes, Kevin A.

    2014-01-01

    Regulated changes in gene expression underlie many biological processes, but globally profiling cell-to-cell variations in transcriptional regulation is problematic when measuring single cells. Transcriptome-wide identification of regulatory heterogeneities can be robustly achieved by randomly collecting small numbers of cells followed by statistical analysis. However, this stochastic-profiling approach blurs out the expression states of the individual cells in each pooled sample. Here, we show that the underlying distribution of single-cell regulatory states can be deconvolved from stochastic-profiling data through maximum-likelihood inference. Guided by the mechanisms of transcriptional regulation, we formulated plausible mixture models for cell-to-cell regulatory heterogeneity and maximized the resulting likelihood functions to infer model parameters. Inferences were validated both computationally and experimentally for different mixture models, which included regulatory states for multicellular function that were occupied by as few as 1 in 40 cells of the population. Importantly, when the method was extended to programs of heterogeneously coexpressed transcripts, we found that population-level inferences were much more accurate with pooled samples than with one-cell samples when the extent of sampling was limited. Our deconvolution method provides a means to quantify the heterogeneous regulation of molecular states efficiently and gain a deeper understanding of the heterogeneous execution of cell decisions. PMID:24449900

  20. Chikusetsusaponin IVa methyl ester induces cell cycle arrest by the inhibition of nuclear translocation of β-catenin in HCT116 cells

    SciTech Connect

    Lee, Kyung-Mi; Yun, Ji Ho; Lee, Dong Hwa; Park, Young Gyun; Son, Kun Ho; Nho, Chu Won; Kim, Yeong Shik

    2015-04-17

    We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica, has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers. - Highlights: • CME inhibits cell proliferation in HCT116 cells. • CME increases cell cycle arrest at G0/G1 phase and apoptosis. • CME attenuates cyclin D1 and regulates cell cycle regulatory proteins. • CME inhibits β-catenin translocation to nucleus.

  1. T regulatory cells: Achilles' heel of Mycobacterium tuberculosis infection?

    PubMed

    Parkash, Om; Agrawal, Sonali; Madhan Kumar, M

    2015-07-01

    T regulatory cells (Treg) constitute a specialized subset of T cells that play a pivotal role in preventing the occurrence of autoimmune diseases by suppressing deleterious activities of immune cells. Contrarily, they can have adverse effect on immune response against infectious diseases where Treg weaken the host immunity leading to enhanced microbial load and thereby increase in severity of the disease. Here, we have attempted to review plethora of information documenting prevalence of Treg in tuberculosis (TB) and their involvement in progression and immunopathogenesis of the disease. Further, we have laid emphasis on the possible use of Treg as a biomarker for determining the TB treatment efficacy. Also, we have discussed the probable contribution of Treg in dampening the efficacy of BCG, the anti-TB vaccine. Finally, we have speculated some of the possible strategies which might be explored by exploiting Treg for enhancing the efficacy of TB management. PMID:25948475

  2. Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 3 Inhibits Gamma Interferon and Major Histocompatibility Complex Class II Expression▿†

    PubMed Central

    Schmidt, Katharina; Wies, Effi; Neipel, Frank

    2011-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) carries four genes with homology to human interferon regulatory factors (IRFs). One of these IRFs, the viral interferon regulatory factor 3 (vIRF-3), is expressed in latently infected primary effusion lymphoma (PEL) cells and required for their continuous proliferation. Moreover, vIRF-3 is known to be involved in modulation of the type I interferon (IFN) response. We now show that vIRF-3 also interferes with the type II interferon system and antigen presentation to the adaptive immune system. Starting with an analysis of the transcriptome, we show that vIRF-3 inhibits expression of major histocompatibility complex class II (MHC II) molecules: small interfering RNA (siRNA)-mediated knockdown of vIRF-3 in KSHV-infected PEL cell lines resulted in increased MHC II levels; overexpression of vIRF-3 in KSHV-negative B cells leads to downmodulation of MHC II. This regulation could be traced back to inhibition of class II transactivator (CIITA) transcription by vIRF-3. Reporter assays revealed that the gamma interferon (IFN-γ)-sensitive CIITA promoters PIV and PIII were inhibited by vIRF-3. Consistently, IFN-γ levels increased upon vIRF-3 knockdown in PEL cells. IFN-γ regulation by vIRF-3 was confirmed in reporter assays as well as by upregulation of typical IFN-γ target genes upon knockdown of vIRF-3 in PEL cells. In summary, we conclude that vIRF-3 contributes to the viral immunoevasion by downregulation of IFN-γ and CIITA and thus MHC II expression. PMID:21345951

  3. Ethylene Upregulates Auxin Biosynthesis in Arabidopsis Seedlings to Enhance Inhibition of Root Cell Elongation[W

    PubMed Central

    Swarup, Ranjan; Perry, Paula; Hagenbeek, Dik; Van Der Straeten, Dominique; Beemster, Gerrit T.S.; Sandberg, Göran; Bhalerao, Rishikesh; Ljung, Karin; Bennett, Malcolm J.

    2007-01-01

    Ethylene represents an important regulatory signal for root development. Genetic studies in Arabidopsis thaliana have demonstrated that ethylene inhibition of root growth involves another hormone signal, auxin. This study investigated why auxin was required by ethylene to regulate root growth. We initially observed that ethylene positively controls auxin biosynthesis in the root apex. We subsequently demonstrated that ethylene-regulated root growth is dependent on (1) the transport of auxin from the root apex via the lateral root cap and (2) auxin responses occurring in multiple elongation zone tissues. Detailed growth studies revealed that the ability of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to inhibit root cell elongation was significantly enhanced in the presence of auxin. We conclude that by upregulating auxin biosynthesis, ethylene facilitates its ability to inhibit root cell expansion. PMID:17630275

  4. Exchange Protein Directly Activated by cAMP Modulates Regulatory T-Cell-Mediated Immunosuppression

    PubMed Central

    Almahariq, Muayad; Mei, Fang C.; Wang, Hui; Cao, Anthony T.; Yao, Suxia; Soong, Lynn; Sun, Jiaren; Cong, Yingzi; Chen, Ju; Cheng, Xiaodong

    2016-01-01

    The cyclic adenosine monophosphate (cAMP) signaling pathway plays an essential role in immune functions. In this study we examined the role of the cAMP/EPAC1 (exchange protein directly activated by cAMP) axis in regulatory T-cell (Treg)-mediated immune suppression using genetic and pharmacologic approaches. Genetic deletion of EPAC1 in Treg and effector T-cells (Teff) synergistically attenuated Treg-mediated suppression of Teff. Mechanistically, EPAC1 inhibition enhanced activation of the transcription factor STAT3 and up-regulated SMAD7 expression while down-regulating expression of SMAD4. Consequently, CD4+T-cells were desensitized to TGF-β1, a cytokine employed by Treg cells to exert a broad inhibitory function within the immune system. Furthermore, deletion of EPAC1 led to production of significant levels of OVA-IgG antibodies in a low dose oral tolerance mouse mode. These in vivo observations are consistent with the finding that EPAC1 plays an important role in Treg-mediated suppression. More importantly, pharmacological inhibition of EPAC1 using an EPAC specific inhibitor recapitulates the EPAC1 deletion phenotype both in vivo and in vitro. Our results show that EPAC1 boosts Treg-mediated suppression, and identify EPAC1 as a target with broad therapeutic potential since Treg cells are involved in numerous pathologies including autoimmunity, infections, and a wide range of cancers. PMID:25339598

  5. Disrupted regulatory T cell homeostasis in inflammatory bowel diseases

    PubMed Central

    Pedros, Christophe; Duguet, Fanny; Saoudi, Abdelhadi; Chabod, Marianne

    2016-01-01

    In the gut, where billions of non-self-antigens from the food and the microbiota are present, the immune response must be tightly regulated to ensure both host protection against pathogenic microorganisms and the absence of immune-related pathologies. It has been well documented that regulatory T cells (Tregs) play a pivotal role in this context. Indeed, Tregs are able to prevent excessive inflammation, which can lead to the rupture of intestinal homeostasis observed in inflammatory bowel diseases (IBDs). Both the worldwide incidence and prevalence of such diseases have increased throughout the latter part of the 20th century. Therefore, it is crucial to understand how Tregs suppress the colitogenic immune cells to establish new treatments for patients suffering from IBDs. In this review, we will first summarize the results obtained in animal model studies that highlight the importance of Tregs in maintaining intestinal homeostasis and describe the specific suppressive mechanisms involved. Next, our current knowledge about Tregs contribution to human IBDs will be reviewed, as well as the current therapeutic perspective on using Tregs for clinical IBD treatment and the challenges that remain to be resolved to ensure both the safety and effectiveness of these therapies in targeting this critical immune-regulatory cell population. PMID:26811641

  6. Prospective Clinical Testing of Regulatory Dendritic Cells in Organ Transplantation

    PubMed Central

    Thomson, Angus W.; Zahorchak, Alan F.; Ezzelarab, Mohamed B.; Butterfield, Lisa H.; Lakkis, Fadi G.; Metes, Diana M.

    2016-01-01

    Dendritic cells (DC) are rare, professional antigen-presenting cells with ability to induce or regulate alloimmune responses. Regulatory DC (DCreg) with potential to down-modulate acute and chronic inflammatory conditions that occur in organ transplantation can be generated in vitro under a variety of conditions. Here, we provide a rationale for evaluation of DCreg therapy in clinical organ transplantation with the goal of promoting sustained, donor-specific hyporesponsiveness, while lowering the incidence and severity of rejection and reducing patients’ dependence on anti-rejection drugs. Generation of donor- or recipient-derived DCreg that suppress T cell responses and prolong transplant survival in rodents or non-human primates has been well-described. Recently, good manufacturing practice (GMP)-grade DCreg have been produced at our Institution for prospective use in human organ transplantation. We briefly review experience of regulatory immune therapy in organ transplantation and describe our experience generating and characterizing human monocyte-derived DCreg. We propose a phase I/II safety study in which the influence of donor-derived DCreg combined with conventional immunosuppression on subclinical and clinical rejection and host alloimmune responses will be examined in detail. PMID:26858719

  7. CTLA-4 promotes Foxp3 induction and regulatory T cell accumulation in the intestinal lamina propria.

    PubMed

    Barnes, M J; Griseri, T; Johnson, A M F; Young, W; Powrie, F; Izcue, A

    2013-03-01

    Thymic induction of CD4(+)Foxp3(+) regulatory T (Treg) cells relies on CD28 costimulation and high-affinity T-cell receptor (TCR) signals, whereas Foxp3 (forkhead box P3) induction on activated peripheral CD4(+) T cells is inhibited by these signals. Accordingly, the inhibitory molecule CTLA-4 (cytotoxic T-lymphocyte antigen 4) promoted, but was not essential for CD4(+) T-cell Foxp3 induction in vitro. We show that CTLA-4-deficient cells are equivalent to wild-type cells in the thymic induction of Foxp3 and maintenance of Foxp3 populations in the spleen and mesenteric lymph nodes, but their accumulation in the colon, where Treg cells specific for commensal bacteria accumulate, is impaired. In a T cell-transfer model of colitis, the two known CTLA-4 ligands, B7-1 and B7-2, had largely redundant roles in inducing inflammation and promoting Treg cell function. However, B7-2 proved more efficient than B7-1 in inducing Foxp3 in vitro and in vivo. Our data reveal an unappreciated role for CTLA-4 in establishing the Foxp3(+) compartment in the intestine. PMID:22910217

  8. Inhibition of FOXP3/NFAT Interaction Enhances T Cell Function after TCR Stimulation.

    PubMed

    Lozano, Teresa; Villanueva, Lorea; Durántez, Maika; Gorraiz, Marta; Ruiz, Marta; Belsúe, Virginia; Riezu-Boj, José I; Hervás-Stubbs, Sandra; Oyarzábal, Julen; Bandukwala, Hozefa; Lourenço, Ana R; Coffer, Paul J; Sarobe, Pablo; Prieto, Jesús; Casares, Noelia; Lasarte, Juan J

    2015-10-01

    Regulatory T cell (Treg) activity is modulated by a cooperative complex between the transcription factor NFAT and FOXP3, a lineage specification factor for Tregs. FOXP3/NFAT interaction is required to repress expression of IL-2, upregulate expression of the Treg markers CTLA4 and CD25, and confer suppressor function to Tregs. However, FOXP3 is expressed transiently in conventional CD4(+) T cells upon TCR stimulation and may lead to T cell hyporesponsiveness. We found that a short synthetic peptide able to inhibit FOXP3/NFAT interaction impaired suppressor activity of conventional Tregs in vitro. Specific inhibition of FOXP3/NFAT interaction with this inhibitory peptide revealed that FOXP3 downregulates NFAT-driven promoter activity of CD40L and IL-17. Inhibition of FOXP3/NFAT interaction upregulated CD40L expression on effector T cells and enhanced T cell proliferation and IL-2, IFN-γ, IL-6, or IL-17 production in response to TCR stimulation. The inhibitory peptide impaired effector T cell conversion into induced Tregs in the presence of TGF-β. Moreover, in vivo peptide administration showed antitumor efficacy in mice bearing Hepa129 or TC1 tumor cells when combined with sorafenib or with an antitumor vaccine, respectively. Our results suggest that inhibition of NFAT/FOXP3 interaction might improve antitumor immunotherapies. PMID:26324768

  9. Tumor necrosis factor receptor superfamily costimulation couples T cell receptor signal strength to thymic regulatory T cell differentiation

    PubMed Central

    Mahmud, Shawn A.; Manlove, Luke S.; Schmitz, Heather M.; Xing, Yan; Wang, Yanyan; Owen, David L.; Schenkel, Jason M.; Boomer, Jonathan S.; Green, Jonathan M.; Yagita, Hideo; Chi, Hongbo; Hogquist, Kristin A.; Farrar, Michael A.

    2014-01-01

    Regulatory T (Treg) cells express tumor necrosis factor receptor superfamily (TNFRSF) members, but their role in thymic Treg development is undefined. We demonstrate that Treg progenitors highly express the TNFRSF members GITR, OX40, and TNFR2. Expression of these receptors correlates directly with T cell receptor (TCR) signal strength, and requires CD28 and the kinase TAK1. Neutralizing TNFSF ligands markedly reduced Treg development. Conversely, TNFRSF agonists enhanced Treg differentiation by augmenting IL-2R/STAT5 responsiveness. GITR-ligand costimulation elicited a dose-dependent enrichment of lower-affinity cells within the Treg repertoire. In vivo, combined inhibition of GITR, OX40 and TNFR2 abrogated Treg development. Thus TNFRSF expression on Treg progenitors translates strong TCR signals into molecular parameters that specifically promote Treg differentiation and shape the Treg repertoire. PMID:24633226

  10. Scorpion venom component III inhibits cell proliferation by modulating NF-κB activation in human leukemia cells

    PubMed Central

    SONG, XIANGFENG; ZHANG, GUOJUN; SUN, AIPING; GUO, JIQIANG; TIAN, ZHONGWEI; WANG, HUI; LIU, YUFENG

    2012-01-01

    Scorpion venom contains various groups of compounds that exhibit anticancer activity against a variety of malignancies through a poorly understood mechanism. While the aberrant activation of nuclear factor κB (NF-κB) has been linked with hematopoietic malignancies, we hypothesized that scorpion venom mediates its effects by modulating the NF-κB signaling pathway. In the present study, we examined the effects of scorpion venom component III (SVCIII) on the human leukemia cell lines THP-1 and Jurkat and focused on the NF-κB signaling pathway. Our results showed that SVCIII inhibited cell proliferation, caused cell cycle arrest at G1 phase and inhibited the expression of cell cycle regulatory protein cyclin D1 in a dose-dependent manner in THP-1 and Jurkat cells. SVCIII also suppressed the constitutive NF-κB activation through inhibition of the phosphorylation and degradation of IκBα. NF-κB luciferase reporter activity was also inhibited by SVCIII. Our data suggest that SVCIII, a natural compound, may exert its antiproliferative effects by inhibiting the activation of NF-κB and, thus, has potential use in the treatment of hematopoietic malignancies, alone or in combination with other agents. PMID:23060939

  11. Comparison of Regulatory T Cells in Hemodialysis Patients and Healthy Controls: Implications for Cell Therapy in Transplantation

    PubMed Central

    Afzali, Behdad; Edozie, Francis C.; Fazekasova, Henrieta; Scottà, Cristiano; Mitchell, Peter J.; Canavan, James B.; Kordasti, Shahram Y.; Chana, Prabhjoat S.; Ellis, Richard; Lord, Graham M.; John, Susan; Hilton, Rachel; Lechler, Robert I.

    2013-01-01

    Summary Background and objectives Cell-based therapy with natural (CD4+CD25hiCD127lo) regulatory T cells to induce transplant tolerance is now technically feasible. However, regulatory T cells from hemodialysis patients awaiting transplantation may be functionally/numerically defective. Human regulatory T cells are also heterogeneous, and some are able to convert to proinflammatory Th17 cells. This study addresses the suitability of regulatory T cells from hemodialysis patients for cell-based therapy in preparation for the first clinical trials in renal transplant recipients (the ONE Study). Design, setting, participants, & measurements Healthy controls and age- and sex-matched hemodialysis patients without recent illness/autoimmune disease on established, complication-free hemodialysis for a minimum of 6 months were recruited. Circulating regulatory T cells were studied by flow cytometry to compare the regulatory T cell subpopulations. Regulatory T cells from members of each group were compared for suppressive function and plasticity (IL-17–producing capacity) before and after in vitro expansion with and without Rapamycin, using standard assays. Results Both groups had similar total regulatory T cells and subpopulations I and III. In each subpopulation, regulatory T cells expressed similar levels of the function-associated markers CD27, CD39, HLA-DR, and FOXP3. Hemodialysis regulatory T cells were less suppressive, expanded poorly compared with healthy control regulatory T cells, and produced IL-17 in the absence of Rapamycin. However, Rapamycin efficiently expanded hemodialysis regulatory T cells to a functional and stable cell product. Conclusions Rapamycin-based expansion protocols should enable clinical trials of cell-based immunotherapy for the induction of tolerance to renal allografts using hemodialysis regulatory T cells. PMID:23580782

  12. Foxo transcription factors control regulatory T cell development and function

    PubMed Central

    Kerdiles, Yann M.; Stone, Erica L.; Beisner, Daniel L.; McGargill, Maureen A.; Ch'en, Irene L.; Stockmann, Christian; Katayama, Carol D.; Hedrick, Stephen M.

    2010-01-01

    SUMMARY Foxo transcription factors integrate extrinsic signals to regulate cell division, differentiation and survival, and specific functions of lymphoid and myeloid cells. Here we showed the absence of Foxo1 severely curtailed the development of Foxp3+ regulatory T (Treg) cells, and those that developed were nonfunctional in vivo. The loss of function included diminished CTLA-4 receptor expression as the Ctla4 gene was a direct target of Foxo1. T cell specific loss of Foxo1 resulted in exocrine pancreatitis, hind limb paralysis, multi-organ lymphocyte infiltration, anti-nuclear antibodies and expanded germinal centers. Foxo-mediated control over Treg cell specification was further revealed by the inability of TGF-β cytokine to suppress T-bet transcription factor in the absence of Foxo1, resulting in IFN-γ-secretion. In addition the absence of Foxo3 exacerbated the effects of the loss of Foxo1. Thus, Foxo transcription factors guide the contingencies of T cell differentiation and specific functions of effector cell populations. PMID:21167754

  13. Digitoxin and a synthetic monosaccharide analog inhibit cell viability in lung cancer cells

    SciTech Connect

    Elbaz, Hosam A.; Stueckle, Todd A.; Wang, Hua-Yu Leo; O'Doherty, George A.; Lowry, David T.; Sargent, Linda M.; Wang, Liying; Dinu, Cerasela Zoica; Rojanasakul, Yon

    2012-01-01

    Mechanisms of digitoxin-inhibited cell growth and induced apoptosis in human non-small cell lung cancer (NCI-H460) cells remain unclear. Understanding how digitoxin or derivate analogs induce their cytotoxic effect below therapeutically relevant concentrations will help in designing and developing novel, safer and more effective anti-cancer drugs. In this study, NCI-H460 cells were treated with digitoxin and a synthetic analog D6-MA to determine their anti-cancer activity. Different concentrations of digitoxin and D6-MA were used and the subsequent changes in cell morphology, viability, cell cycle, and protein expressions were determined. Digitoxin and D6-MA induced dose-dependent apoptotic morphologic changes in NCI-H460 cells via caspase-9 cleavage, with D6-MA possessing 5-fold greater potency than digitoxin. In comparison, non-tumorigenic immortalized bronchial and small airway epithelial cells displayed significantly less apoptotic sensitivity compared to NCI-H460 cells suggesting that both digitoxin and D6-MA were selective for NSCLC. Furthermore, NCI-H460 cells arrested in G(2)/M phase following digitoxin and D6-MA treatment. Post-treatment evaluation of key G2/M checkpoint regulatory proteins identified down-regulation of cyclin B1/cdc2 complex and survivin. Additionally, Chk1/2 and p53 related proteins experienced down-regulation suggesting a p53-independent cell cycle arrest mechanism. In summary, digitoxin and D6-MA exert anti-cancer effects on NCI-H460 cells through apoptosis or cell cycle arrest, with D6-MA showing at least 5-fold greater potency relative to digitoxin. -- Highlights: ► Digitoxin and synthetic analog D6-MA induced apoptotic morphologic changes in NCI-H460 cells in a dose-dependent manner. ► Apoptotic cell death induced by analog was 5-fold more potent when compared to digitoxin. ► NCI-H460 cells arrested in G(2)/M phase following digitoxin (≥ 5 nM) and analog (≥ 1 nM) treatment. ► Digitoxin inhibited the expression of cyclin

  14. Functional and genomic analyses of FOXP3-transduced Jurkat-T cells as regulatory T (Treg)-like cells

    SciTech Connect

    Kim, Joon-Young Kim, Han-Jong; Hurt, Elaine M.; Chen, Xin; Howard, O.M. Zack; Farrar, William L.

    2007-10-12

    FOXP3, a forkhead transcription factor is essential for the development and function of CD4{sup +}CD25{sup +} regulatory T cells (Tregs). In contrast to conversion of murine naive T cells to Tregs by transduction of Foxp3, it is controversial whether ectopic expression of FOXP3 in human CD4{sup +} T cells is sufficient for acquisition of suppressive activity. Here, we show that retroviral transduction of FOXP3 induces a Treg phenotype in human leukemic CD4{sup +} Jurkat-T cells, evidenced by increased expression of Treg-associated cell surface markers as well as inhibition of cytokine production. Furthermore, FOXP3-transduced Jurkat-T cells suppress the proliferation of human CD4{sup +}CD25{sup -} T cells. Additionally, DNA microarray analysis identifies Treg-related genes regulated by FOXP3. Our study demonstrates that enforced expression of FOXP3 confers Treg-like properties on Jurkat-T cells, which can be a convenient and efficient Treg-like cell model for further study to identify Treg cell surface markers and target genes regulated by FOXP3.

  15. Sparstolonin B Inhibits Pro-Angiogenic Functions and Blocks Cell Cycle Progression in Endothelial Cells

    PubMed Central

    Bateman, Henry R.; Liang, Qiaoli; Fan, Daping; Rodriguez, Vanessa; Lessner, Susan M.

    2013-01-01

    Sparstolonin B (SsnB) is a novel bioactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including diabetic retinopathy, tumor growth, and atherosclerosis. In functional assays, SsnB inhibited endothelial cell tube formation (Matrigel method) and cell migration (Transwell method) in a dose-dependent manner. Microarray experiments with human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells (HCAECs) demonstrated differential expression of several hundred genes in response to SsnB exposure (916 and 356 genes, respectively, with fold change ≥2, p<0.05, unpaired t-test). Microarray data from both cell types showed significant overlap, including genes associated with cell proliferation and cell cycle. Flow cytometric cell cycle analysis of HUVECs treated with SsnB showed an increase of cells in the G1 phase and a decrease of cells in the S phase. Cyclin E2 (CCNE2) and Cell division cycle 6 (CDC6) are regulatory proteins that control cell cycle progression through the G1/S checkpoint. Both CCNE2 and CDC6 were downregulated in the microarray data. Real Time quantitative PCR confirmed that gene expression of CCNE2 and CDC6 in HUVECs was downregulated after SsnB exposure, to 64% and 35% of controls, respectively. The data suggest that SsnB may exert its anti-angiogenic properties in part by downregulating CCNE2 and CDC6, halting progression through the G1/S checkpoint. In the chick chorioallantoic membrane (CAM) assay, SsnB caused significant reduction in capillary length and branching number relative to the vehicle control group. Overall, SsnB caused a significant reduction in angiogenesis (ANOVA, p<0.05), demonstrating its ex vivo efficacy. PMID:23940584

  16. Sparstolonin B inhibits pro-angiogenic functions and blocks cell cycle progression in endothelial cells.

    PubMed

    Bateman, Henry R; Liang, Qiaoli; Fan, Daping; Rodriguez, Vanessa; Lessner, Susan M

    2013-01-01

    Sparstolonin B (SsnB) is a novel bioactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including diabetic retinopathy, tumor growth, and atherosclerosis. In functional assays, SsnB inhibited endothelial cell tube formation (Matrigel method) and cell migration (Transwell method) in a dose-dependent manner. Microarray experiments with human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells (HCAECs) demonstrated differential expression of several hundred genes in response to SsnB exposure (916 and 356 genes, respectively, with fold change ≥2, p<0.05, unpaired t-test). Microarray data from both cell types showed significant overlap, including genes associated with cell proliferation and cell cycle. Flow cytometric cell cycle analysis of HUVECs treated with SsnB showed an increase of cells in the G1 phase and a decrease of cells in the S phase. Cyclin E2 (CCNE2) and Cell division cycle 6 (CDC6) are regulatory proteins that control cell cycle progression through the G1/S checkpoint. Both CCNE2 and CDC6 were downregulated in the microarray data. Real Time quantitative PCR confirmed that gene expression of CCNE2 and CDC6 in HUVECs was downregulated after SsnB exposure, to 64% and 35% of controls, respectively. The data suggest that SsnB may exert its anti-angiogenic properties in part by downregulating CCNE2 and CDC6, halting progression through the G1/S checkpoint. In the chick chorioallantoic membrane (CAM) assay, SsnB caused significant reduction in capillary length and branching number relative to the vehicle control group. Overall, SsnB caused a significant reduction in angiogenesis (ANOVA, p<0.05), demonstrating its ex vivo efficacy. PMID:23940584

  17. Modulation of cell cycle regulatory protein expression and suppression of tumor growth by mimosine in nude mice.

    PubMed

    Chang, H C; Weng, C F; Yen, M H; Chuang, L Y; Hung, W C

    2000-10-01

    Our previous results demonstrated that the plant amino acid mimosine blocked cell cycle progression and suppressed proliferation of human lung cancer cells in vitro by multiple mechanisms. Inhibition of cyclin D1 expression or induction of cyclin-dependent kinase inhibitor p21WAF1 expression was found in mimosine-treated lung cancer cells. However, whether mimosine may modulate the expression of these cell cycle regulatory proteins and suppress tumor growth in vivo is unknown. In this study, we examined the anti-cancer effect of mimosine on human H226 lung cancer cells grown in nude mice. Our results demonstrated that mimosine inhibits cyclin D1 and induces p21WAF1 expression in vivo. Furthermore, results of TUNEL analysis indicated that mimosine may induce apoptosis to suppress tumor growth in nude mice. Collectively, these results suggest that mimosine exerts anti-cancer effect in vivo and might be useful in the therapy of lung cancer. PMID:10995875

  18. Inhibition of Cancer Cell Migration by Multiwalled Carbon Nanotubes.

    PubMed

    García-Hevia, Lorena; Valiente, Rafael; Fernández-Luna, José L; Flahaut, Emmanuel; Rodríguez-Fernández, Lidia; Villegas, Juan C; González, Jesús; Fanarraga, Mónica L

    2015-08-01

    Inhibiting cancer cell migration and infiltration to other tissues makes the difference between life and death. Multiwalled carbon nanotubes (MWCNTs) display intrinsic biomimetic properties with microtubules, severely interfering with the function of these protein filaments during cell proliferation, triggering cell death. Here it is shown MWCNTs disrupt the centrosomal microtubule cytoskeletal organization triggering potent antimigratory effects in different cancer cells. PMID:26097131

  19. Mullerian inhibiting substance inhibits ovarian cell growth through an Rb-independent mechanism.

    PubMed

    Ha, T U; Segev, D L; Barbie, D; Masiakos, P T; Tran, T T; Dombkowski, D; Glander, M; Clarke, T R; Lorenzo, H K; Donahoe, P K; Maheswaran, S

    2000-11-24

    Müllerian inhibiting substance (MIS), a transforming growth factor-beta family member, causes regression of the Müllerian duct in male embryos. MIS overexpression in transgenic mice ablates the ovary, and MIS inhibits the growth of ovarian cancer cell lines in vitro, suggesting a key role for this hormone in postnatal development of the ovary. This report describes a mechanism for MIS-mediated growth inhibition in both a human epithelial ovarian cancer cell line and a cell line derived from normal ovarian surface epithelium, which is the origin of human epithelial ovarian cancers. MIS-treated cells accumulated in the G(1) phase of the cell cycle and subsequently underwent apoptosis. MIS up-regulated the cyclin-dependent kinase inhibitor p16 through an MIS type II receptor-mediated mechanism and inhibited growth in the absence of detectable or inactive Rb protein. Prolonged treatment with MIS down-regulated the Rb-related protein p130 and increased the Rb family-regulated transcription factor E2F1, overexpression of which inhibited growth. These findings demonstrate that p16 is required for MIS-mediated growth inhibition in ovarian epithelial cells and tumor cells and suggest that up-regulation of E2F1 also plays a role in this process. PMID:10958795

  20. [Inhibition of adenovirus reproduction in cell culture by specific antibodies].

    PubMed

    Povnytsia, O Iu; Nosach, L M; Zhovnovata, V L; Zahorodnia, S D; Vantsak, N P; Tokarchuk, L V; Polishchuk, O M; Diachenko, N S

    2009-01-01

    The capacity of specific antibodies to inhibit the reproduction of homo- and heterologous adenoviruses in Hela cell added to culture medium after virus adsorption was studied. The inhibiting effect of polyclonal antivirus and monospecific antihexone antibodies to homo- and heterologous adenoviruses was shown. The effect was more expressed when using antibodies to homologous antibodies. The intensity of inhibition depended on antibodies concentration in the medium and infecting dose of the virus. Essential reduction of the quantity of infected cells and a decrease of the titer of adenovirus synthesized in the presence of homo- and heterologous antibodies was shown but adenovirus reproduction was not inhibited completely. PMID:19663330

  1. Mitochondrial uncouplers inhibit hepatic stellate cell activation

    PubMed Central

    2012-01-01

    Background Mitochondrial dysfunction participates in the progression of several pathologies. Although there is increasing evidence for a mitochondrial role in liver disease, little is known about its contribution to hepatic stellate cell (HSC) activation. In this study we investigated the role of mitochondrial activity through mild uncoupling during in vitro activation of HSCs. Methods Cultured primary human and mouse HSCs were treated with the chemical uncouplers FCCP and Valinomycin. ATP levels were measured by luciferase assay and production of reactive oxygen species was determined using the fluorescent probe DCFH-DA. Possible cytotoxicity by uncoupler treatment was evaluated by caspase 3/7 activity and cytoplasmic protease leakage. Activation of HSCs and their response to the pro-fibrogenic cytokine TGF-β was evaluated by gene expression of activation markers and signal mediators using RT-qPCR. Proliferation was measured by incorporation of EdU and protein expression of α-smooth muscle actin was analyzed by immunocytochemistry and western blot. Results FCCP and Valinomycin treatment mildly decreased ATP and reactive oxygen species levels. Both uncouplers increased the expression of mitochondrial genes such as Tfam and COXIV while inducing morphological features of quiescent mouse HSCs and abrogating TGF-β signal transduction. Mild uncoupling reduced HSC proliferation and expression of pro-fibrogenic markers of mouse and human HSCs. Conclusions Mild mitochondrial uncoupling inhibits culture-induced HSC activation and their response to pro-fibrogenic cytokines like TGF-β. These results therefore suggest mitochondrial uncoupling of HSCs as a strategy to reduce progression of liver fibrosis. PMID:22686625

  2. Inhibition of caspases prevents ototoxic and ongoing hair cell death

    NASA Technical Reports Server (NTRS)

    Matsui, Jonathan I.; Ogilvie, Judith M.; Warchol, Mark E.

    2002-01-01

    Sensory hair cells die after acoustic trauma or ototoxic insults, but the signal transduction pathways that mediate hair cell death are not known. Here we identify several important signaling events that regulate the death of vestibular hair cells. Chick utricles were cultured in media supplemented with the ototoxic antibiotic neomycin and selected pharmacological agents that influence signaling molecules in cell death pathways. Hair cells that were treated with neomycin exhibited classically defined apoptotic morphologies such as condensed nuclei and fragmented DNA. Inhibition of protein synthesis (via treatment with cycloheximide) increased hair cell survival after treatment with neomycin, suggesting that hair cell death requires de novo protein synthesis. Finally, the inhibition of caspases promoted hair cell survival after neomycin treatment. Sensory hair cells in avian vestibular organs also undergo continual cell death and replacement throughout mature life. It is unclear whether the loss of hair cells stimulates the proliferation of supporting cells or whether the production of new cells triggers the death of hair cells. We examined the effects of caspase inhibition on spontaneous hair cell death in the chick utricle. Caspase inhibitors reduced the amount of ongoing hair cell death and ongoing supporting cell proliferation in a dose-dependent manner. In isolated sensory epithelia, however, caspase inhibitors did not affect supporting cell proliferation directly. Our data indicate that ongoing hair cell death stimulates supporting cell proliferation in the mature utricle.

  3. IRF-1 inhibits NF-κB activity, suppresses TRAF2 and cIAP1 and induces breast cancer cell specific growth inhibition

    PubMed Central

    Armstrong, Michaele J; Stang, Michael T; Liu, Ye; Yan, Jin; Pizzoferrato, Eva; Yim, John H

    2015-01-01

    Interferon Regulatory Factor (IRF)-1, originally identified as a transcription factor of the human interferon (IFN)-β gene, mediates tumor suppression and may inhibit oncogenesis. We have shown that IRF-1 in human breast cancer cells results in the down-regulation of survivin, tumor cell death, and the inhibition of tumor growth in vivo in xenogeneic mouse models. In this current report, we initiate studies comparing the effect of IRF-1 in human nonmalignant breast cell and breast cancer cell lines. While IRF-1 in breast cancer cells results in growth inhibition and cell death, profound growth inhibition and cell death are not observed in nonmalignant human breast cells. We show that TNF-α or IFN-γ induces IRF-1 in breast cancer cells and results in enhanced cell death. Abrogation of IRF-1 diminishes TNF-α and IFN-γ-induced apoptosis. We test the hypothesis that IRF-1 augments TNF-α-induced apoptosis in breast cancer cells. Potential signaling networks elicited by IRF-1 are investigated by evaluating the NF-κB pathway. TNF-α and/or IFN-γ results in decreased presence of NF-κB p65 in the nucleus of breast cancer cells. While TNF-α and/or IFN-γ can induce IRF-1 in nonmalignant breast cells, a marked change in NF-κB p65 is not observed. Moreover, the ectopic expression of IRF-1 in breast cancer cells results in caspase-3, -7, -8 cleavage, inhibits NF-κB activity, and suppresses the expression of molecules involved in the NF-κB pathway. These data show that IRF-1 in human breast cancer cells elicits multiple signaling networks including intrinsic and extrinsic cell death and down-regulates molecules involved in the NF-κB pathway. PMID:26011589

  4. IRF-1 inhibits NF-κB activity, suppresses TRAF2 and cIAP1 and induces breast cancer cell specific growth inhibition.

    PubMed

    Armstrong, Michaele J; Stang, Michael T; Liu, Ye; Yan, Jin; Pizzoferrato, Eva; Yim, John H

    2015-01-01

    Interferon Regulatory Factor (IRF)-1, originally identified as a transcription factor of the human interferon (IFN)-β gene, mediates tumor suppression and may inhibit oncogenesis. We have shown that IRF-1 in human breast cancer cells results in the down-regulation of survivin, tumor cell death, and the inhibition of tumor growth in vivo in xenogeneic mouse models. In this current report, we initiate studies comparing the effect of IRF-1 in human nonmalignant breast cell and breast cancer cell lines. While IRF-1 in breast cancer cells results in growth inhibition and cell death, profound growth inhibition and cell death are not observed in nonmalignant human breast cells. We show that TNF-α or IFN-γ induces IRF-1 in breast cancer cells and results in enhanced cell death. Abrogation of IRF-1 diminishes TNF-α and IFN-γ-induced apoptosis. We test the hypothesis that IRF-1 augments TNF-α-induced apoptosis in breast cancer cells. Potential signaling networks elicited by IRF-1 are investigated by evaluating the NF-κB pathway. TNF-α and/or IFN-γ results in decreased presence of NF-κB p65 in the nucleus of breast cancer cells. While TNF-α and/or IFN-γ can induce IRF-1 in nonmalignant breast cells, a marked change in NF-κB p65 is not observed. Moreover, the ectopic expression of IRF-1 in breast cancer cells results in caspase-3, -7, -8 cleavage, inhibits NF-κB activity, and suppresses the expression of molecules involved in the NF-κB pathway. These data show that IRF-1 in human breast cancer cells elicits multiple signaling networks including intrinsic and extrinsic cell death and down-regulates molecules involved in the NF-κB pathway. PMID:26011589

  5. Blocking p55PIK signaling inhibits proliferation and induces differentiation of leukemia cells.

    PubMed

    Wang, G; Deng, Y; Cao, X; Lai, S; Tong, Y; Luo, X; Feng, Y; Xia, X; Gong, J; Hu, J

    2012-11-01

    p55PIK, a regulatory subunit of phosphatidylinositol 3-kinases, promotes cell cycle progression by interacting with cell cycle modulators such as retinoblastoma protein (Rb) via its unique amino-terminal 24 amino-acid residue (N24). Overexpression of N24 specifically inhibits these interactions and leads to cell cycle arrest. Herein, we describe the generation of a fusion protein (Tat transactivator protein (TAT)-N24) that contains the protein transduction domain and N24, and examined its effects on the proliferation and differentiation of leukemia cells. TAT-N24 not only blocks cell proliferation but remarkably induces differentiation of leukemia cells in vitro and in vivo. Systemically administered TAT-N24 also significantly decreases growth of leukemia cell tumors in animal models. Furthermore, overexpression of p55PIK in leukemia cells leads to increased proliferation; however, TAT-N24 blocks this effect and concomitantly induces differentiation. There is significant upregulation of p55PIK mRNA and protein expression in leukemia cells from patients. TAT-N24 inhibits cell cycle progression and induces differentiation of bone marrow cells derived from patients with several different types of leukemia. These results show that cell-permeable N24 peptide induces leukemia cell differentiation and suggest that p55PIK may be a novel drug target for the treatment of hematopoetic malignancies. PMID:22722333

  6. Single-cell dynamics of mast cell-CD4+ CD25+ regulatory T cell interactions.

    PubMed

    Frossi, Barbara; D'Incà, Federica; Crivellato, Enrico; Sibilano, Riccardo; Gri, Giorgia; Mongillo, Marco; Danelli, Luca; Maggi, Laura; Pucillo, Carlo E

    2011-07-01

    The biological behavior of immune cells is determined by their intrinsic properties and interactions with other cell populations within their microenvironment. Several studies have confirmed the existence of tight spatial interactions between mast cells (MCs) and Tregs in different settings. For instance, we have recently identified the functional cross-talk between MCs and Tregs, through the OX40L-OX40 axis, as a new mechanism of reciprocal influence. However, there is scant information regarding the single-cell dynamics of this process. In this study, time-lapse video microscopy revealed direct interactions between Tregs and MCs in both murine and human cell co-cultures, resulting in the inhibition of the MC degranulation response. MCs incubated with WT, but not OX40-deficient, Tregs mediated numerous and long-lasting interactions and displayed different morphological features lacking the classical signs of exocytosis. MC degranulation and Ca2+ mobilization upon activation were inhibited by Tregs on a single-cell basis, without affecting overall cytokine secretion. Transmission electron microscopy showed ultrastructural evidence of vesicle-mediated secretion reconcilable with the morphological pattern of piecemeal degranulation. Our results suggest that MC morphological and functional changes following MC-Treg interactions can be ascribed to cell-cell contact and represent a transversal, non-species-specific mechanism of immune response regulation. Further research, looking at the molecular composition of this interaction will broaden our understanding of its contribution to immunity. PMID:21509780

  7. GTP cyclohydrolase I inhibition by the prototypic inhibitor 2, 4-diamino-6-hydroxypyrimidine. Mechanisms and unanticipated role of GTP cyclohydrolase I feedback regulatory protein.

    PubMed

    Xie, L; Smith, J A; Gross, S S

    1998-08-14

    2,4-Diamino-6-hydroxypyrimidine (DAHP) is considered to be a selective and direct-acting inhibitor of GTP cyclohydrolase I (GTPCH), the first and rate-limiting enzyme in the pathway for synthesis of tetrahydrobiopterin (BH4). Accordingly, DAHP has been widely employed to distinguish whether de novo BH4 synthesis is required in a given biological system. Although it has been assumed that DAHP inhibits GTPCH by direct competition with substrate GTP, this has never been formally demonstrated. In view of apparent structural homology between DAHP and BH4, we questioned whether DAHP may mimic BH4 in its inhibition of GTPCH by an indirect mechanism, involving interaction with a recently cloned 9.5-kDa protein termed GTPCH Feedback Regulatory Protein (GFRP). We show by reverse transcription-polymerase chain reaction that GFRP mRNA is constitutively expressed in rat aortic smooth muscle cells and further induced by treatment with immunostimulants. Moreover, functional GFRP is expressed and immunostimulant-induced BH4 accumulates in sufficient quantity to trigger feedback inhibition of GTPCH. Studies with DAHP reveal that GFRP is also essential to achieve potent inhibition of GTPCH. Indeed, DAHP inhibits GTPCH by dual mechanisms. At a relatively low concentration, DAHP emulates BH4 and engages the GFRP-dependent feedback inhibitory system; at higher concentrations, DAHP competes directly for binding with GTP substrate. This knowledge predicts that DAHP would preferably target GTPCH in tissues with abundant GFRP. PMID:9694862

  8. MNT inhibits the migration of human hepatocellular carcinoma SMMC7721 cells

    SciTech Connect

    Wu, Jian; Zhou, Qi; Wang, Yafeng; Zhou, Xiangbing; Li, Jiaping

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer MNT is a member of the Myc/Max/Mad network that plays a role in cell proliferation. Black-Right-Pointing-Pointer Our study further emphasized the role of MNT in migration inhibition of SMMC7721 cells. Black-Right-Pointing-Pointer MNT might be a promising target for HCC chemotherapy. -- Abstract: Max binding protein (MNT) is a member of the Myc/Max/Mad network that plays a role in cell proliferation, differentiation and apoptosis. We previously observed that MNT was differentially expressed in hepatocellular carcinoma (HCC) and interacted with Nck1 by 2-DE. Nck family adaptor proteins function to couple tyrosine phosphorylation signals, regulate actin cytoskeletal reorganization and lead to cell motility. In order to investigate the regulatory role of MNT in HCC migration, we used transient transfection with a MNT expressing vector to overexpress MNT protein in SMMC7721 cells, and MNT siRNA to knockdown MNT expression. Rho Family Small GTPase activation assay, Western blots and transwell assay were used to determine the migration potential of cells. We found that knockdown of MNT expression might promote SMMC7721 cell migration, while the overexpressed MNT could significantly inhibit cell migration. It further emphasized the role of MNT in inhibition of cell migration that might be a promising target for HCC chemotherapy.

  9. T Follicular Helper Cells and Regulatory B Cells Dynamics in Systemic Lupus Erythematosus

    PubMed Central

    Chu, Yiwei; Xue, Yu; Xuan, Dandan; Zheng, Shucong; Zou, Hejian

    2014-01-01

    T follicular helper (Tfh) cells aid effector B cells, and augment autoimmunity, whereas the role of Tfh cells on regulatory B (Breg) cells in systemic lupus erythematosus (SLE) is not known. The aim of this study is to investigate the percentage of Breg cells in SLE, and the role of Tfh cells on Breg cells. First, we demonstrated the presence of Breg cells in SLE peripheral blood mononuclear cells and in involved skins. Both the percentage of circulating Breg cells and the ability to produce interleukin-10 (IL-10) were elevated in SLE patients. The percentage of Breg cells increased during SLE flares and decreased following disease remission. Second, Tfh cell expansion was not only related to autoantibody production but also correlated with the increased percentage of Breg cells. Third, in vitro studies revealed that Tfh cell-derived IL-21 could promote IL-10 production and Breg cell differentiation. In conclusions, these data imply that SLE flares may be linked to the expansion of Tfh cells and that Breg cells are increased in a regulatory feedback manner. Thus, SLE development may be associated with the complex regulation of Tfh cells and diverse B cell subsets. PMID:24551101

  10. Regulatory T cell-based therapies for autoimmunity.

    PubMed

    Arellano, Benjamine; Graber, David J; Sentman, Charles L

    2016-08-01

    Autoimmune disorders are long-term diseases that adversely affect the quality of life for patients, and they are one of the top ten leading causes of death. While each autoimmune disorder is unique, they all are caused by a breakdown of tolerance against endogenous proteins. This leads to auto-inflammatory events that promote the destruction of organs in a humoral and cellular immune mediated manner. Treatment options for autoimmunity can involve the use of chemical and biologic agents that suppress inflammation. While these treatment options for patients have shown to be beneficial in autoimmunity, they can result in patients being vulnerable to opportunistic infections. Newer therapies aim to identify methods to specifically block auto-inflammatory immune cells while allowing for an intact immune response to other antigens. T regulatory (Treg) cells are a subtype of the adoptive immune cell that is capable of suppressing inflammatory events in an antigen-specific manner, but they are often poorly functioning within autoimmune patients. Treg cells have been well characterized for their immune modulating capabilities and preclinical and early clinical studies support their therapeutic potential for antigen-specific immune suppression. This review will examine the current understanding of Treg cell function and the therapeutic potential of enhancing Treg cells in patients with inflammatory disorders. PMID:27585233

  11. Emerging regulatory mechanisms in ubiquitin-dependent cell cycle control

    PubMed Central

    Mocciaro, Annamaria; Rape, Michael

    2012-01-01

    The covalent modification of proteins with ubiquitin is required for accurate cell division in all eukaryotes. Ubiquitylation depends on an enzymatic cascade, in which E3 enzymes recruit specific substrates for modification. Among ~600 human E3s, the SCF (Skp1–cullin1–F-box) and the APC/C (anaphase-promoting complex/cyclosome) are known for driving the degradation of cell cycle regulators to accomplish irreversible cell cycle transitions. The cell cycle machinery reciprocally regulates the SCF and APC/C through various mechanisms, including the modification of these E3s or the binding of specific inhibitors. Recent studies have provided new insight into the intricate relationship between ubiquitylation and the cell division apparatus as they revealed roles for atypical ubiquitin chains, new mechanisms of substrate and E3 regulation, as well as extensive crosstalk between ubiquitylation enzymes. Here, we review these emerging regulatory mechanisms of ubiquitin-dependent cell cycle control and discuss how their manipulation might provide therapeutic benefits in the future. PMID:22357967

  12. CCR7 Deficiency Exacerbates Injury in Acute Nephritis Due to Aberrant Localization of Regulatory T Cells

    PubMed Central

    Eller, Kathrin; Weber, Tobias; Pruenster, Monika; Wolf, Anna M.; Mayer, Gert

    2010-01-01

    The homing of dendritic cells and T cells to secondary lymphoid organs requires chemokine receptor 7 (CCR7) expression on these cells. T cells mediate the pathogenesis of experimental accelerated nephrotoxic serum nephritis (NTS), including its suppression by regulatory T cells (Tregs), but the contribution of CCR7 to this disease is unknown. Here, we compared the development of NTS in CCR7-knockout (KO) and wild-type (WT) mice. Compared with WT mice, CCR7KO mice developed more severe disease with significantly more inflammatory cells infiltrating the kidney. These cells included FoxP3+ Tregs, which were virtually absent from WT kidneys. The adoptive transfer of WT Tregs into CCR7KO mice at the time of immunization protected the recipients from disease; these cells homed to secondary lymphoid organs but not to kidneys. Conversely, adoptive transfer of CCR7KO Tregs into WT mice did not inhibit development of NTS. These data suggest that NTS can develop without CCR7 expression, but Treg-mediated disease suppression, which seems to occur in secondary lymphoid organs, requires CCR7. PMID:19917782

  13. Suppression of experimental autoimmune myasthenia gravis by autologous T regulatory cells.

    PubMed

    Aricha, Revital; Reuveni, Debby; Fuchs, Sara; Souroujon, Miriam C

    2016-02-01

    Adoptive transfer of regulatory T (Treg) cells have been employed effectively for suppression of several animal models for autoimmune diseases. In order to employ Treg cell therapy in patients, it is necessary to generate Treg cells from the patient's own cells (autologous) that would be able to suppress effectively the disease in vivo, upon their reintroduction to the patient. Towards this objective, we report in the present study on a protocol for a successful immune-regulation of experimental autoimmune myasthenia gravis (EAMG) by ex vivo--generated autologous Treg cells. For this protocol bone marrow (BM) cells, are first cultured in the presence of GM-CSF, giving rise to a population of CD11c(+)MHCII(+)CD45RA(+)CD8(-) DCs (BMDCs). Splenic CD4(+) T cells are then co-cultured with the differentiated BM cells and expand to 90% of Foxp3(+) Treg cells. In vitro assay exhibits a similar dose dependent manner in the suppression of T effector cells proliferation between Treg cells obtained from either healthy or sick donors. In addition, both Treg cells inhibit similarly the secretion of IFN-γ from activated splenocytes. Administration of 1 × 10(6) ex-vivo generated Treg cells, I.V, to EAMG rats, modulates the disease following a single treatment, given 3 days or 3 weeks after disease induction. Similar disease inhibition was achieved when CD4 cells were taken from either healthy or sick donors. The disease suppression was accompanied by reduced levels of total AChR specific antibodies in the serum. Moreover, due to the polyclonality of the described Treg cell, we have examined whether this treatment approach could be also employed for the treatment of other autoimmune diseases involving Treg cells. Indeed, we demonstrated that the ex-vivo generated autologous Treg cells suppress Adjuvant Arthritis (AA) in rats. This study opens the way for the application of induced autologous Treg cell therapy for myasthenia gravis, as well as for other human autoimmune diseases

  14. Impairment of Regulatory T-Cell Function in Autoimmune Thyroid Disease

    PubMed Central

    Glick, Abigail B.; Wodzinski, Alaina; Fu, Pingfu

    2013-01-01

    Background Autoimmune thyroid disease (AITD) pathogenesis may result from a loss of immune tolerance to thyroid antigens. Regulatory T cells (Tregs) control immune responses, prevent excessive inflammation, and may be dysfunctional in AITD. We investigated the role of Tregs in Hashimoto's thyroiditis (HT) and Graves' disease (GD), complicated by Down syndrome (DS). Our goal was to identify differences in CD4+CD25high Treg function or number in patients with GD and HT, compared to healthy controls (HC). Methods Treg number was assessed by flow cytometric analysis in samples from 20 AITD patients (seven GD, 13 HT), nine HC, and seven individuals with DS, a genetic disorder associated with multiple autoimmune disorders including AITD. Treg function was assessed by the inhibition of proliferation (radioactive thymidine incorporation into DNA) of blood-derived T effector (Teff) cells by Tregs in a coculture. Various methods of stimulation were contrasted. Cytokine levels were determined in conditioned media from the co-cultures. Results No differences were found in the frequency of Tregs as a percentage of CD4+ cells between AITD and HC. AITD Tregs were less capable of inhibiting the proliferation of Teff cells when compared to HC; however, the impairment was dependent on the type of stimulation used. DS patients without AITD exhibited normal Treg function. We observed few differences in cytokine production between HC and AITD patients. Conclusions Tregs from AITD patients are partly dysfunctional, possibly explaining their autoimmunity. Future work will elucidate the diagnostic potential and pathophysiology of Tregs in AITD. PMID:23379353

  15. Research Progress on Regulatory T Cells in Acute Kidney Injury

    PubMed Central

    Wang, Yamei; Tao, Yuhong

    2015-01-01

    Immune inflammation is crucial in mediating acute kidney injury (AKI). Immune cells of both the innate and adaptive immune systems substantially contribute to overall renal damage in AKI. Regulatory T cells (Tregs) are key regulator of immunological function and have been demonstrated to ameliorate injury in several murine experimental models of renal inflammation. Recent studies have illuminated the renal-protective function of Tregs in AKI. Tregs appear to exert beneficial effects in both the acute injury phase and the recovery phase of AKI. Additionally, Tregs-based immunotherapy may represent a promising approach to ameliorate AKI and promote recovery from AKI. This review will highlight the recent insights into the role of Tregs and their therapeutic potential in AKI. PMID:26273681

  16. Special regulatory T cell review: The suppression problem!

    PubMed Central

    Waldmann, Herman

    2008-01-01

    The concept of T-cell mediated suppression evolved more than 30 years ago. At that time it spawned many claims that have not stood the test of time. The rediscovery of suppression phenomena and regulatory T cells over the past 15 years created schizophrenic responses amongst immunologists. Some claimed that the new proponents of suppression were, once again, bringing immunology into disrepute, whilst others have embraced the field with great enthusiasm and novel approaches to clarification. Without faithful repetition of the “old” experiments, it is difficult to establish what was right and what was wrong. Nevertheless, immunologists must now accept that a good number of the old claims were overstated, and reflected poor scientific discipline. “I speak not to disprove what Brutus spoke, But here I am to speak what I do know” Shakespeare. Julius Caesar Act 3, Scene 2. PMID:18154612

  17. Special regulatory T cell review: The suppression problem!

    PubMed

    Waldmann, Herman

    2008-01-01

    The concept of T-cell mediated suppression evolved more than 30 years ago. At that time it spawned many claims that have not stood the test of time. The rediscovery of suppression phenomena and regulatory T cells over the past 15 years created schizophrenic responses amongst immunologists. Some claimed that the new proponents of suppression were, once again, bringing immunology into disrepute, whilst others have embraced the field with great enthusiasm and novel approaches to clarification. Without faithful repetition of the "old" experiments, it is difficult to establish what was right and what was wrong. Nevertheless, immunologists must now accept that a good number of the old claims were overstated, and reflected poor scientific discipline. "I speak not to disprove what Brutus spoke, But here I am to speak what I do know" Shakespeare. Julius Caesar Act 3, Scene 2. PMID:18154612

  18. Metabolic control of regulatory T cell development and function.

    PubMed

    Zeng, Hu; Chi, Hongbo

    2015-01-01

    Foxp3(+) regulatory T cells (Tregs) maintain immune tolerance and play an important role in immunological diseases and cancers. Recent studies have revealed an intricate relationship between Treg biology and host and microbial metabolism. Various metabolites or nutrients produced by host and commensal microbes, such as vitamins and short-chain fatty acids (SCFAs), regulate Treg generation, trafficking, and function. Furthermore, cell intrinsic metabolic programs, orchestrated by mTOR and other metabolic sensors, modulate Foxp3 induction and Treg suppressive activity. Conversely, Tregs are crucial in regulating obesity-associated inflammation and host metabolic balance, and in shaping homeostasis of gut microbiota. We review here the interplay between Tregs and metabolism, with a particular focus on how host, commensal, and cellular metabolism impinge upon Treg homeostasis and function. PMID:25248463

  19. Regulatory Considerations for NK Cells Used in Human Immunotherapy Applications.

    PubMed

    Lee, Dean A

    2016-01-01

    Translating cellular therapy from the laboratory to the clinic is a complicated process that involves scale-up of procedures to generate clinically relevant cell numbers, adaptation to reagents and equipment that are qualified for human use, establishing parameters of safety for reagents and equipment that are not already qualified for human use, codifying these processes into standards of practice and rules of conduct, and obtaining approval from regulatory bodies based on those codified standards and rules. As the laws and regulations that apply to cellular therapy will vary by time and geography, this chapter reviews some common key principles for the manufacturing of NK cells for human use that will need to be considered within the constraints of local policies and regulations. PMID:27177680

  20. Rapid regulatory control of plant cell expansion and wall relaxation

    SciTech Connect

    Cosgrove, D.J.

    1991-08-14

    The aim of this project is to elucidate the biophysical and cellular mechanisms that control plant cell expansion. At present we are attempting to characterize the kinetics of the system(s) responsible for regulatory and compensatory behavior of growing cells and tissues. This work is significantly because it indicates that biochemical loosening and biophysical stress relaxation of the wall are part of a feedback loop controlling growth. This report briefly summarizes the efforts and results of the past 12 months. In large part, we have been trying to analyze the nature of growth rate noise,'' i.e. spontaneous and often erratic variations in growth rate. We are obtaining evidence that such noise'' is not random, but rather reveals an underlying growth mechanism with complex dynamics.

  1. Synthetic retinoid AM80 inhibits Th17 cells and ameliorates experimental autoimmune encephalomyelitis.

    PubMed

    Klemann, Christian; Raveney, Benjamin J E; Klemann, Anna K; Ozawa, Tomoko; von Hörsten, Stephan; Shudo, Koichi; Oki, Shinji; Yamamura, Takashi

    2009-06-01

    Recent evidence suggests that interleukin-17-producing CD4(+) T cells (Th17 cells) are the dominant pathogenic cellular component in autoimmune inflammatory diseases, including multiple sclerosis. It has recently been demonstrated that all-trans retinoic acid can suppress Th17 differentiation and promote the generation of Foxp3(+) regulatory T cells via retinoic acid receptor signals. Here, we investigated the effects of AM80, a synthetic retinoid with enhanced biological properties to all-trans retinoic acid, on Th17 differentiation and function and evaluated its therapeutic potential in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. AM80 treatment was more effective than all-trans retinoic acid in inhibiting Th17 differentiation in vitro. Oral administration of AM80 was protective for the early development of EAE and the down-modulation of Th17 differentiation and effector functions in vivo. Moreover, AM80 inhibited interleukin-17 production by splenic memory T cells, in vitro-differentiated Th17 cells, and central nervous system-infiltrating effector T cells. Accordingly, AM80 was effective when administered therapeutically after the onset of EAE. Continuous AM80 treatment, however, was ineffective at inhibiting late EAE symptoms despite the maintained suppression of RORgammat and interleukin-17 expression levels by central nervous system-infiltrating T cells. We reveal that continuous AM80 treatment also led to the suppression of interleukin-10 production by a distinct T cell subset that expressed both Foxp3 and RORgammat. These findings suggest that retinoid signaling regulates both inflammatory Th17 cells and Th17-like regulatory cells. PMID:19389933

  2. Synthetic Retinoid AM80 Inhibits Th17 Cells and Ameliorates Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Klemann, Christian; Raveney, Benjamin J.E.; Klemann, Anna K.; Ozawa, Tomoko; von Hörsten, Stephan; Shudo, Koichi; Oki, Shinji; Yamamura, Takashi

    2009-01-01

    Recent evidence suggests that interleukin-17-producing CD4+ T cells (Th17 cells) are the dominant pathogenic cellular component in autoimmune inflammatory diseases, including multiple sclerosis. It has recently been demonstrated that all-trans retinoic acid can suppress Th17 differentiation and promote the generation of Foxp3+ regulatory T cells via retinoic acid receptor signals. Here, we investigated the effects of AM80, a synthetic retinoid with enhanced biological properties to all-trans retinoic acid, on Th17 differentiation and function and evaluated its therapeutic potential in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. AM80 treatment was more effective than all-trans retinoic acid in inhibiting Th17 differentiation in vitro. Oral administration of AM80 was protective for the early development of EAE and the down-modulation of Th17 differentiation and effector functions in vivo. Moreover, AM80 inhibited interleukin-17 production by splenic memory T cells, in vitro-differentiated Th17 cells, and central nervous system-infiltrating effector T cells. Accordingly, AM80 was effective when administered therapeutically after the onset of EAE. Continuous AM80 treatment, however, was ineffective at inhibiting late EAE symptoms despite the maintained suppression of RORγt and interleukin-17 expression levels by central nervous system-infiltrating T cells. We reveal that continuous AM80 treatment also led to the suppression of interleukin-10 production by a distinct T cell subset that expressed both Foxp3 and RORγt. These findings suggest that retinoid signaling regulates both inflammatory Th17 cells and Th17-like regulatory cells. PMID:19389933

  3. Non-cell-autonomous effects of vector-expressed regulatory RNAs in mammalian heart cells.

    PubMed

    Kizana, E; Cingolani, E; Marbán, E

    2009-09-01

    In mammalian cells, small regulatory RNA molecules are able to modulate gene expression in a cell-autonomous manner. In contrast, this mechanism of gene regulation can occur systemically in plants and nematodes. The existence of similar cell-to-cell transmission in mammalian cells has been explored, but generalizibilty and mechanistic insights have remained elusive. Here, we show that small regulatory RNA molecules are capable of a non-cell-autonomous effect between primary cardiac myocytes through a gap-junction-dependent mechanism. Co-culture experiments showed that both Dicer-processed small-interfering RNAs (siRNAs) and Drosha-processed microRNAs (miRNAs) were capable of target gene knockdown and physiological effects in a non-cell-autonomous manner. Target gene siRNA molecules were detected in recipient cells, indicating transfer of the primary effector molecule. All of these effects were abrogated by dominant-negative molecular suppression of gap junction function. Our results show that both siRNAs and miRNAs are capable of a non-cell-autonomous effect between mammalian cells through gap junctions. The recognition of this biological process raises the novel therapeutic prospect of a bystander effect after gene transfer to tissues bearing gap junctions and for cell engineering with a view to creating regulatory RNA donor cells that exert their influence throughout a syncytium. PMID:19516277

  4. T-cell regulatory mechanisms in specific immunotherapy.

    PubMed

    Jutel, Marek; Akdis, Cezmi A

    2008-01-01

    Allergen-specific immunotherapy (SIT) is the only treatment which leads to a lifelong tolerance against previously disease-causing allergens due to restoration of normal immunity against allergens. The description of T-regulatory (Treg) cells being involved in prevention of sensitization to allergens has led to great interest whether they represent a major target for allergen-SIT and whether it would be possible to manipulate Treg cells to increase its efficacy. Activationinduced cell death, anergy and/or immune response modulation by Treg cells are essential mechanisms of peripheral T-cell tolerance. There is growing evidence that anergy, tolerance and active suppression are not entirely distinct, but rather represent linked mechanisms possibly involving the same cells and multiple suppressor mechanisms. Skewing of allergen-specific effector T cells to Treg cells appears as a crucial event in the control of healthy immune response to allergens and successful allergen-SIT. The Treg cell response is characterized by abolished allergen- induced specific T-cell proliferation and suppressed Thelper (Th)1- and Th2-type cytokine secretion. In addition, mediators of allergic inflammation that trigger cAMP-associated G-protein-coupled receptors, such as histamine receptor-2, may contribute to peripheral tolerance mechanisms. The increased levels of interleukin-10 and transforming growth factor-Beta that are produced by Treg cells potently suppress IgE production, while simultaneously increasing production of non-inflammatory isotypes IgG4 and IgA, respectively. In addition, Treg cells directly or indirectly suppress effector cells of allergic inflammation such as mast cells, basophils and eosinophils. In conclusion, peripheral tolerance to allergens is controlled by multiple active suppression mechanisms. It is associated with regulation of antibody isotypes and effector cells to the direction of a healthy immune response. By the application of the recent knowledge in Treg

  5. Regulatory multitasking of tolerogenic dendritic cells - lessons taken from vitamin d3-treated tolerogenic dendritic cells.

    PubMed

    Nikolic, Tatjana; Roep, Bart O

    2013-01-01

    Tolerogenic dendritic cells (DCs) work through silencing of differentiated antigen-specific T cells, activation and expansion of naturally occurring T regulatory cells (Tregs), transfer of regulatory properties to T cells, and the differentiation of naïve T cells into Tregs. Due to an operational definition based on T cell activation assays, the identity of tolerogenic DCs has been a matter of debate and it need not represent a specialized DC subset. Human tolerogenic DCs generated in vitro using inhibitory cytokines, growth factors, natural immunomodulators, or genetic manipulation have been effective and several of these tolerogenic DCs are currently being tested for clinical use. Ex vivo generated tolerogenic DCs reduce activation of naïve T cells using various means, promote a variety of regulatory T cells and most importantly, frequently show stable inhibitory phenotypes upon repetitive maturation with inflammatory factors. Yet, tolerogenic DCs differ with respect to the phenotype or the number of regulatory mechanisms they employ to modulate the immune system. In our experience, tolerogenic DCs generated using the biologically active form of vitamin D (VD3-DCs), alone, or combined with dexamethasone are proficient in their immunoregulatory functions. These tolerogenic DCs show a stable maturation-resistant semi-mature phenotype with low expression of activating co-stimulatory molecules, no production of the IL-12 family of cytokines and high expression of inhibitory molecules and IL-10. VD3-DCs induce increased apoptosis of effector T cells and induce antigen-specific regulatory T cells, which work through linked suppression ensuring infectious tolerance. Lessons learned on VD3-DCs help understanding the contribution of different pattern-recognition receptors (PRRs) and secondary signals to the tolerogenic function and how a cross-talk between DCs and T cells translates into immune regulation. PMID:23717310

  6. MiR-503 inhibits hepatocellular carcinoma cell growth via inhibition of insulin-like growth factor 1 receptor

    PubMed Central

    Xiao, Yao; Tian, Qinggang; He, Jiantai; Huang, Ming; Yang, Chao; Gong, Liansheng

    2016-01-01

    MicroRNAs (miRs) have been demonstrated to play key roles in the development and progression of hepatocellular carcinoma (HCC). However, the regulatory mechanism of miR-503 in HCC has not been fully uncovered. In this study, we found that miR-503 was significantly downregulated in HCC tissues compared to nontumorous liver tissues. Moreover, lower miR-503 levels were associated with the malignant progression of HCC, and the expression of miR-503 was also decreased in several common HCC cell lines compared to normal human liver cell line THLE-3. Overexpression of miR-503 inhibited proliferation but induced apoptosis of LM3 and HepG2 cells. Bioinformatical analysis and luciferase reporter assay further identified insulin-like growth factor 1 receptor (IGF-1R) as a novel target of miR-503 in 293T cells. Moreover, overexpression of miR-503 led to a significant decrease in the protein levels of IGF-1R, while knockdown of miR-503 enhanced its protein levels in LM3 and HepG2 cells. Besides, overexpression of IGF-1R reversed the effects of miR-503-mediated HCC cell proliferation and apoptosis, indicating that IGF-1R acts as a downstream effector of miR-503 in HCC cells. Furthermore, IGF-1R was found to be significantly upregulated in HCC tissues compared to nontumorous liver tissues. In addition, the mRNA levels of IGF-1R were inversely correlated to the miR-503 levels in the HCC tissues. Thus, we demonstrate that miR-503 inhibits the proliferation and induces the apoptosis of HCC cells, partly at least, by directly targeting IGF-1R, and suggest that IGF-1R may serve as a promising target for the treatment of HCC. PMID:27366090

  7. Hyperoxia Inhibits T Cell Activation in Mice

    NASA Astrophysics Data System (ADS)

    Hughes-Fulford, M.; Meissler, J.; Aguayo, E. T.; Globus, R.; Aguado, J.; Candelario, T.

    2013-02-01

    , spleens were removed and the splenocytes were isolated and kept as individual biological samples. We have also examined transcription factors (JASPAR) and pathways of the immune system to help us understand the mechanism of regulation. Results: Our recent mouse immunology experiment aboard STS-131 suggests that the early T cell immune response was inhibited in animals that have been exposed to spaceflight, even 24 hours after return to earth. Moreover, recent experiments in hyperoxic mice show that many of the same genes involved in early T cell activation were altered. Specifically, expression of IL-2Rα, Cxcl2, TNFα, FGF2, LTA and BCL2 genes are dysregulated in mice exposed to hyperoxia. Conclusions: If these hyperoxia-induced changes of gene expression in early T cell activation are additive to the changes seen in the microgravity of spaceflight, there could be an increased infection risk to EVA astronauts, which should be addressed prior to conducting a Mars or other long-term mission.

  8. T Cells: Soldiers and Spies—The Surveillance and Control of Effector T Cells by Regulatory T Cells

    PubMed Central

    2015-01-01

    Traditionally, T cells were CD4+ helper or CD8+ cytotoxic T cells, and with antibodies, they were the soldiers of immunity. Now, many functionally distinct subsets of activated CD4+ and CD8+ T cells have been described, each with distinct cytokine and transcription factor expression. For CD4+ T cells, these include Th1 cells expressing the transcription factor T-bet and cytokines IL-2, IFN-γ, and TNF-β; Th2 cells expressing GATA-3 and the cytokines IL-4, IL-5, and IL-13; and Th17 cells expressing RORγt and cytokines IL-17A, IL-17F, IL-21, and IL-22. The cytokines produced determine the immune inflammation that they mediate. T cells of the effector lineage can be naïve T cells, recently activated T cells, or memory T cells that can be distinguished by cell surface markers. T regulatory cells or spies were characterized as CD8+ T cells expressing I-J in the 1970s. In the 1980s, suppressor cells fell into disrepute when the gene for I-J was not present in the mouse MHC I region. At that time, a CD4+ T cell expressing CD25, the IL-2 receptor-α, was identified to transfer transplant tolerance. This was the same phenotype of activated CD4+CD25+ T cells that mediated rejection. Thus, the cells that could induce tolerance and undermine rejection had similar badges and uniforms as the cells effecting rejection. Later, FOXP3, a transcription factor that confers suppressor function, was described and distinguishes T regulatory cells from effector T cells. Many subtypes of T regulatory cells can be characterized by different expressions of cytokines and receptors for cytokines or chemokines. In intense immune inflammation, T regulatory cells express cytokines characteristic of effector cells; for example, Th1-like T regulatory cells express T-bet, and IFN-γ–like Th1 cells and effector T cells can change sides by converting to T regulatory cells. Effector T cells and T regulatory cells use similar molecules to be activated and mediate their function, and thus, it can be

  9. Adoptive Immunotherapy using Regulatory T cells and Virus-specific T cells Derived from Cord Blood

    PubMed Central

    Hanley, Patrick J.; Bollard, Catherine M.; Brunstein, Claudio G

    2014-01-01

    Cord blood transplantation, an alternative to traditional stem cell transplants (bone marrow or peripheral blood stem cell transplantation), is an attractive option for patients lacking suitable stem cell transplant donors. Cord blood units have also proven to be a valuable donor source for the development of cellular therapeutics. Virus-specific T cells and regulatory T cells are two cord blood derived products that have shown promise in early phase clinical trials to prevent and/or treat viral infections and graft-versus-host disease (GvHD), respectively. Here we describe how current strategies utilizing cord blood-derived regulatory T cells and virus-specific T cells have been developed to improve outcomes for cord blood transplant recipients. PMID:25632003

  10. Tregalizumab – A Monoclonal Antibody to Target Regulatory T Cells

    PubMed Central

    König, Martin; Rharbaoui, Faiza; Aigner, Silke; Dälken, Benjamin; Schüttrumpf, Jörg

    2016-01-01

    Regulatory T cells (Tregs) represent a subpopulation of CD4+ T cells, which are essential for the maintenance of immunological tolerance. The absence or dysfunction of Tregs can lead to autoimmunity and allergies. The restoration of functional Tregs and/or Treg cell numbers represents a novel and attractive approach for the treatment of autoimmune diseases, e.g., rheumatoid arthritis (RA). The CD4 cell surface receptor is a target for modulation of T cell function. Monoclonal antibodies (mAbs) against CD4 have previously been tested for the treatment of autoimmune diseases, including RA. Furthermore, in model systems, anti-CD4 antibodies are able to induce tolerance and mediate immunomodulatory effects through a variety of mechanisms. Despite the availability of innovative and effective therapies for RA, many patients still have persistently active disease or experience adverse events that can limit use. A growing body of evidence suggests that Treg modulation could offer a new therapeutic strategy in RA and other autoimmune disorders. Here, we describe tregalizumab (BT-061), which is a novel, non-depleting IgG1 mAb that binds to a unique epitope of CD4. Tregalizumab represents the first humanized anti-CD4 mAb that selectively induces Treg activation. PMID:26834751

  11. Cholera-like enterotoxins and Regulatory T cells.

    PubMed

    Basset, Christelle; Thiam, Fatou; Martino, Cyrille Di; Holton, John; Clements, John D; Kohli, Evelyne

    2010-07-01

    Cholera toxin (CT) and the heat-labile enterotoxin of E. coli (LT), as well as their non toxic mutants, are potent mucosal adjuvants of immunization eliciting mucosal and systemic responses against unrelated co-administered antigens in experimental models and in humans (non toxic mutants). These enterotoxins are composed of two subunits, the A subunit, responsible for an ADP-ribosyl transferase activity and the B subunit, responsible for cell binding. Paradoxically, whereas the whole toxins have adjuvant properties, the B subunits of CT (CTB) and of LT (LTB) have been shown to induce antigen specific tolerance when administered mucosally with antigens in experimental models as well as, recently, in humans, making them an attractive strategy to prevent or treat autoimmune or allergic disorders. Immunomodulation is a complex process involving many cell types notably antigen presenting cells and regulatory T cells (Tregs). In this review, we focus on Treg cells and cholera-like enterotoxins and their non toxic derivates, with regard to subtype, in vivo/in vitro effects and possible role in the modulation of immune responses to coadministered antigens. PMID:22069660

  12. Inhibition of host cell catalase by Mycoplasma pneumoniae: a possible mechanism for cell injury.

    PubMed Central

    Almagor, M; Yatziv, S; Kahane, I

    1983-01-01

    This study demonstrates that viable Mycoplasma pneumoniae cells inhibit catalase activity in several types of intact human cells as well as in solution. Human erythrocyte catalase was inhibited up to 72%, and the inhibition of catalase in human cultured skin fibroblasts, lung carcinoma epithelial cells, and ciliated epithelial cells from human nasal polyps ranged between 75 and 80%. UV light-killed mycoplasmas failed to inhibit catalase activity both in intact cells and in vitro. After M. pneumoniae infection of human cultured skin fibroblasts, the level of malonyldialdehyde, an indicator for membrane lipid peroxidation, was 3.5 times higher than in control fibroblasts. Virulent M. pneumoniae completely inhibited catalase activity in solution, whereas the nonvirulent strains had a lesser ability to inhibit catalase activity. These findings suggest that as a result of host cell catalase inhibition by M. pneumoniae, the toxicity of the hydrogen peroxide generated by the microorganism and the affected cell is enhanced, thereby inducing host cell damage. PMID:6407999

  13. Regulatory elements and structural features of Beta vulgaris polygalacturonase-inhibiting protein gene for fungal and pest control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polygalacturonase-inhibiting proteins (PGIPs) are involved in plant defense. PGIPs are cell wall leucine-rich repeat (LRR) proteins that are known to inhibit pathogen and pest polygalacturonases (PGs) during the infection process. Several sugar beet (Beta vulgaris L.) PGIP genes (BvPGIP) were clon...

  14. First Insight into the Kinome of Human Regulatory T Cells

    PubMed Central

    König, Sebastian; Probst-Kepper, Michael; Reinl, Tobias; Jeron, Andreas; Huehn, Jochen; Schraven, Burkhart; Jänsch, Lothar

    2012-01-01

    Regulatory T cells (Tregs) are essential for controlling peripheral tolerance by the active suppression of various immune cells including conventional T effector cells (Teffs). Downstream of the T cell receptor (TCR), more than 500 protein kinases encoded by the human genome have to be considered in signaling cascades regulating the activation of Tregs and Teffs, respectively. Following TCR engagement, Tregs posses a number of unique attributes, such as constitutive expression of Foxp3, hyporesponsiveness and poor cytokine production. Furthermore, recent studies showed that altered regulation of protein kinases is important for Treg function. These data indicate that signaling pathways in Tregs are distinctly organized and alterations at the level of protein kinases contribute to the unique Treg phenotype. However, kinase-based signaling networks in Tregs are poorly understood and necessitate further systematic characterization. In this study, we analyzed the differential expression of kinases in Tregs and Teffs by using a kinase-selective proteome strategy. In total, we revealed quantitative information on 185 kinases expressed in the human CD4+ T cell subsets. The majority of kinases was equally abundant in both T cell subsets, but 11 kinases were differentially expressed in Tregs. Most strikingly, Tregs showed an altered expression of cell cycle kinases including CDK6. Quantitative proteomics generates first comparative insight into the kinase complements of the CD4+ Teff and Treg subset. Treg-specific expression pattern of 11 protein kinases substantiate the current opinion that TCR-mediated signaling cascades are altered in Tregs and further suggests that Tregs exhibit significant specificities in cell-cycle control and progression. PMID:22815858

  15. Regulatory issues in cell-based therapy for clinical purposes.

    PubMed

    Casaroli-Marano, Ricardo P; Tabera, Jaime; Vilarrodona, Anna; Trias, Esteve

    2014-01-01

    Rapid development in the fields of cellular and molecular biology, biotechnology, and bioengineering medicine has brought new, highly innovative treatments and medicinal products, some of which contain viable cells and tissues associated with scaffolds and devices. These new cell-based therapy approaches in regenerative medicine have great potential for use in the treatment of a number of diseases that at present cannot be managed effectively. Given the unique challenges associated with the development of human cell-based medicinal products, great care is required in the development of procedures, practices, and regulation. In cell therapy, appropriate methodologies in the areas of production, reproducibility, maintenance, and delivery are essential for accurate definition and reliable assurance of the suitability and quality of the final products. Recently, the official European Community agencies (EMA) and the relevant authority in the USA (FDA) have made significant efforts to establish regulatory guidance for use in the application of the cell-based therapies for human patients. The guidelines surrounding cell-based therapy take into account the current legislation, but focus less on the heterogeneity and requirements of individual human cell-based products, including specific combination products and applications. When considering guidelines and regulation, a risk assessment approach is an effective method of identifying priority areas for the development of human cell-based medicinal products. Additionally, effective design and thorough validation of the manufacturing process in line with existing Good Manufacturing Practices (GMPs) and quality control regimes and a program that ensures the traceability and biovigilance of the final products are also all essential elements to consider. PMID:24732772

  16. Lipopolysaccharide from Rhodobacter sphaeroides Attenuates Microglia-Mediated Inflammation and Phagocytosis and Directs Regulatory T Cell Response

    PubMed Central

    Gaikwad, Sagar; Agrawal-Rajput, Reena

    2015-01-01

    Microglia activation and neuroinflammation are key events during the progression of neurodegenerative disorders. Microglia exhibits toll-like receptors (TLRs), with predominant expression of TLR4, inducing aberrant neuroinflammation and exacerbated neurotoxicity. Studies suggest that microglia initiate infiltration of T cells into the brain that critically influence disease conditions. We report that LPS-Rs, through TLR4 antagonism, significantly inhibit TLR4 mediated inflammatory molecules like IL-1β, IL-6, TNF-α, COX-2, iNOS, and NO. LPS-Rs regulates JNK/p38 MAPKs and p65-NF-κB signaling pathways, which we report as indispensible for LPS induced neuroinflammation. LPS-Rs mitigates microglial phagocytic activity and we are first to report regulatory role of LPS-Rs which blocked microglia mediated inflammation and apoptotic cell death. LPS-Rs significantly inhibits expression of costimulatory molecules CD80, CD86, and CD40. Chemokine receptor, CCR5, and T cell recruitment chemokines, MIP-1α and CCL5, were negatively regulated by LPS-Rs. Furthermore, LPS-Rs significantly inhibited lymphocyte proliferation with skewed regulatory T (Treg) cell response as evidenced by increased FOXP3, IL-10, and TGF-β. Additionally, LPS-Rs serves to induce coordinated immunosuppressive response and confer tolerogenic potential to activated microglia extending neurosupportive microenvironment. TLR4 antagonism can be a strategy providing neuroprotection through regulation of microglia as well as the T cells. PMID:26457222

  17. Stem cell regulatory function mediated by expression of a novel mouse Oct4 pseudogene

    SciTech Connect

    Lin, Huey; Shabbir, Arsalan; Molnar, Merced; Lee, Techung . E-mail: chunglee@buffalo.edu

    2007-03-30

    Multiple pseudogenes have been proposed for embryonic stem (ES) cell-specific genes, and their abundance suggests that some of these potential pseudogenes may be functional. ES cell-specific expression of Oct4 regulates stem cell pluripotency and self-renewing state. Although Oct4 expression has been reported in adult tissues during gene reprogramming, the detected Oct4 signal might be contributed by Oct4 pseudogenes. Among the multiple Oct4 transcripts characterized here is a {approx}1 kb clone derived from P19 embryonal carcinoma stem cells, which shares a {approx}87% sequence homology with the parent Oct4 gene, and has the potential of encoding an 80-amino acid product (designated as Oct4P1). Adenoviral expression of Oct4P1 in mesenchymal stem cells promotes their proliferation and inhibits their osteochondral differentiation. These dual effects of Oct4P1 are reminiscent of the stem cell regulatory function of the parent Oct4, and suggest that Oct4P1 may be a functional pseudogene or a novel Oct4-related gene with a unique function in stem cells.

  18. Metabolic control of type 1 regulatory (Tr1) cell differentiation by AHR and HIF1-α

    PubMed Central

    Mascanfroni, Ivan D.; Takenaka, Maisa C.; Yeste, Ada; Patel, Bonny; Wu, Yan; Kenison, Jessica E.; Siddiqui, Shafiuddin; Basso, Alexandre S.; Otterbein, Leo E.; Pardoll, Drew M.; Pan, Fan; Priel, Avner; Clish, Clary B.; Robson, Simon C.; Quintana, Francisco J.

    2015-01-01

    Our understanding of the pathways that regulate lymphocyte metabolism, as well as the effects of metabolism and its products on the immune response, is still limited. We report that a metabolic program controlled by the transcription factors hypoxia inducible factor-1α (HIF1-α) and aryl hydrocarbon receptor (AHR) supports the differentiation of type 1 regulatory (Tr1) cells. HIF1-α controls the early metabolic reprograming of Tr1 cells. At later time points, AHR promotes HIF1-α degradation and takes control of Tr1 cell metabolism. Extracellular adenosine triphosphate (eATP) and hypoxia, linked to inflammation, trigger AHR inactivation by HIF1-α and inhibit Tr1 cell differentiation. Conversely, CD39 promotes Tr1 cell differentiation by depleting eATP. CD39 also contributes to Tr1 suppressive activity by generating adenosine in cooperation with CD73 expressed by responder T cells and antigen presenting cells. These results suggest that HIF1-α and AHR integrate immunological, metabolic and environmental signals to regulate the immune response. PMID:26005855

  19. Galectin-8 promotes regulatory T cell differentiation by modulating IL-2 and TGFβ signaling

    PubMed Central

    Sampson, James F.; Suryawanshi, Amol; Chen, Wei-Sheng; Rabinovich, Gabriel A.; Panjwani, Noorjahan

    2015-01-01

    Galectins have emerged as potent immunoregulatory molecules that control chronic inflammation through distinct mechanisms. Galectin-8 (Gal-8), a tandem-repeat type galectin with unique preference for α2,3-sialylated glycans, is ubiquitously expressed, but little is known about its role in T cell differentiation. Here, we report that Gal-8 promotes the polyclonal differentiation of primary mouse Treg cells in vitro. We further show that Gal-8 also facilitates antigen-specific differentiation of regulatory T (Treg) cells, and that Treg cells polarized in the presence of Gal-8 express cytotoxic T lymphocyte antigen-4 (CTLA-4) and IL-10 at a higher frequency than control Treg cells, and efficiently inhibit proliferation of activated T cells in vitro. Investigation of the mechanism by which Gal-8 promotes Treg conversion revealed that Gal-8 activates TGFβ signaling and promotes sustained IL-2R signaling. Taken together, these data suggest that Gal-8 promotes the differentiation of highly suppressive Treg cells, which has implications for the treatment of inflammatory and autoimmune diseases. PMID:26282995

  20. Ozone selectively inhibits growth of human cancer cells

    SciTech Connect

    Sweet, F.; Kao, M.S.; Lee, S.C.; Hagar, W.L.; Sweet, W.E.

    1980-08-01

    The growth of human cancer cells from lung, breast, and uterine tumors was selectively inhibited in a dose-dependent manner by ozone at 0.3 to 0.8 part per million of ozone in ambient air during 8 days of culture. Human lung diploid fibroblasts served as noncancerous control cells. The presence of ozone at 0.3 to 0.5 part per million inhibited cancer cell growth 40 and 60 percent, respectively. The noncancerous lung cells were unaffected at these levels. Exposure to ozone at 0.8 part per million inhibited cancer cell growth more than 90 percent and control cell growth less than 50 percent. Evidently, the mechanisms for defense against ozone damage are impaired in human cancer cells.

  1. MicroRNAs targeting TGFβ signalling underlie the regulatory T cell defect in multiple sclerosis.

    PubMed

    Severin, Mary E; Lee, Priscilla W; Liu, Yue; Selhorst, Amanda J; Gormley, Matthew G; Pei, Wei; Yang, Yuhong; Guerau-de-Arellano, Mireia; Racke, Michael K; Lovett-Racke, Amy E

    2016-06-01

    Transforming growth factor beta (TGFβ) signalling is critical for regulatory T cell development and function, and regulatory T cell dysregulation is a common observation in autoimmune diseases, including multiple sclerosis. In a comprehensive miRNA profiling study of patients with multiple sclerosis naïve CD4 T cells, 19 differentially expressed miRNAs predicted to target the TGFβ signalling pathway were identified, leading to the hypothesis that miRNAs may be responsible for the regulatory T cell defect observed in patients with multiple sclerosis. Patients with multiple sclerosis had reduced levels of TGFβ signalling components in their naïve CD4 T cells. The differentially expressed miRNAs negatively regulated the TGFβ pathway, resulting in a reduced capacity of naïve CD4 T cells to differentiate into regulatory T cells. Interestingly, the limited number of regulatory T cells, that did develop when these TGFβ-targeting miRNAs were overexpressed, were capable of suppressing effector T cells. As it has previously been demonstrated that compromising TGFβ signalling results in a reduced regulatory T cell repertoire insufficient to control autoimmunity, and patients with multiple sclerosis have a reduced regulatory T cell repertoire, these data indicate that the elevated expression of multiple TGFβ-targeting miRNAs in naïve CD4 T cells of patients with multiple sclerosis impairs TGFβ signalling, and dampens regulatory T cell development, thereby enhancing susceptibility to developing multiple sclerosis. PMID:27190026

  2. Apaf1 inhibition promotes cell recovery from apoptosis.

    PubMed

    Gortat, Anna; Sancho, Mónica; Mondragón, Laura; Messeguer, Àngel; Pérez-Payá, Enrique; Orzáez, Mar

    2015-11-01

    The protein apoptotic protease activating factor 1 (Apaf1) is the central component of the apoptosome, a multiprotein complex that activates procaspase-9 after cytochrome c release from the mitochondria in the intrinsic pathway of apoptosis. We have developed a vital method that allows fluorescence-activated cell sorting of cells at different stages of the apoptotic pathway and demonstrated that upon pharmacological inhibition of Apaf1, cells recover from doxorubicin- or hypoxia-induced early apoptosis to normal healthy cell. Inhibiting Apaf1 not only prevents procaspase-9 activation but delays massive mitochondrial damage allowing cell recovery. PMID:26361785

  3. Inhibition of brain tumor cell proliferation by alternating electric fields

    SciTech Connect

    Jeong, Hyesun; Oh, Seung-ick; Hong, Sunghoi E-mail: radioyoon@korea.ac.kr; Sung, Jiwon; Jeong, Seonghoon; Yoon, Myonggeun E-mail: radioyoon@korea.ac.kr; Koh, Eui Kwan

    2014-11-17

    This study was designed to investigate the mechanism by which electric fields affect cell function, and to determine the optimal conditions for electric field inhibition of cancer cell proliferation. Low-intensity (<2 V/cm) and intermediate-frequency (100–300 kHz) alternating electric fields were applied to glioblastoma cell lines. These electric fields inhibited cell proliferation by inducing cell cycle arrest and abnormal mitosis due to the malformation of microtubules. These effects were significantly dependent on the intensity and frequency of applied electric fields.

  4. Increased Expression of Regulatory T Cells and Down-Regulatory Molecules in Lepromatous Leprosy

    PubMed Central

    Palermo, Maria L.; Pagliari, Carla; Trindade, Maria Angela B.; Yamashitafuji, Tania M.; Duarte, Alberto José S.; Cacere, Camila R.; Benard, Gil

    2012-01-01

    T regulatory cells (Tregs) play an important role in the mechanism of host's failure to control pathogen dissemination in severe forms of different chronic granulomatous diseases, but their role in leprosy has not yet been elucidated; 28 newly diagnosed patients (16 patients with lepromatous leprosy and 12 patients with tuberculoid leprosy) and 6 healthy Mycobacterium leprae-exposed individuals (contacts) were studied. Tregs were quantified by flow cytometry (CD4+ CD25+ Foxp3+) in peripheral blood mononuclear cells stimulated in vitro with a M. leprae antigenic preparation and phytohemagglutinin as well as in skin lesions by immunohistochemistry. The lymphoproliferative (LPR), interleukin-10 (IL-10), and interferon-γ (IFN-γ) responses of the in vitro-stimulated peripheral blood mononuclear cells and the in situ expression of IL-10, transforming growth factor-β (TGF-β), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) were also determined. We show that M. leprae antigens induced significantly lower LPR but significantly higher Treg numbers in lepromatous than tuberculoid patients and contacts. Mitogen-induced LPR and Treg frequencies were not significantly different among the three groups. Tregs were also more frequent in situ in lepromatous patients, and this finding was paralleled by increased expression of the antiinflammatory molecules IL-10 and CTLA-4 but not TGF-β. In lepromatous patients, Tregs were intermingled with vacuolized hystiocyte infiltrates all over the lesion, whereas in tuberculoid patients, Tregs were rare. Our results suggest that Tregs are present in increased numbers, and they may have a pathogenic role in leprosy patients harboring uncontrolled bacillary multiplication but not in those individuals capable of limiting M. leprae growth. PMID:22556091

  5. Increased expression of regulatory T cells and down-regulatory molecules in lepromatous leprosy.

    PubMed

    Palermo, Maria L; Pagliari, Carla; Trindade, Maria Angela B; Yamashitafuji, Tania M; Duarte, Alberto José S; Cacere, Camila R; Benard, Gil

    2012-05-01

    T regulatory cells (Tregs) play an important role in the mechanism of host's failure to control pathogen dissemination in severe forms of different chronic granulomatous diseases, but their role in leprosy has not yet been elucidated; 28 newly diagnosed patients (16 patients with lepromatous leprosy and 12 patients with tuberculoid leprosy) and 6 healthy Mycobacterium leprae-exposed individuals (contacts) were studied. Tregs were quantified by flow cytometry (CD4+ CD25+ Foxp3+) in peripheral blood mononuclear cells stimulated in vitro with a M. leprae antigenic preparation and phytohemagglutinin as well as in skin lesions by immunohistochemistry. The lymphoproliferative (LPR), interleukin-10 (IL-10), and interferon-γ (IFN-γ) responses of the in vitro-stimulated peripheral blood mononuclear cells and the in situ expression of IL-10, transforming growth factor-β (TGF-β), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) were also determined. We show that M. leprae antigens induced significantly lower LPR but significantly higher Treg numbers in lepromatous than tuberculoid patients and contacts. Mitogen-induced LPR and Treg frequencies were not significantly different among the three groups. Tregs were also more frequent in situ in lepromatous patients, and this finding was paralleled by increased expression of the antiinflammatory molecules IL-10 and CTLA-4 but not TGF-β. In lepromatous patients, Tregs were intermingled with vacuolized hystiocyte infiltrates all over the lesion, whereas in tuberculoid patients, Tregs were rare. Our results suggest that Tregs are present in increased numbers, and they may have a pathogenic role in leprosy patients harboring uncontrolled bacillary multiplication but not in those individuals capable of limiting M. leprae growth. PMID:22556091

  6. Percentage of Peripheral CD19+CD24hiCD38hi Regulatory B Cells in Neonatal Sepsis Patients and Its Functional Implication

    PubMed Central

    Pan, Xiao; Ji, Zuoquan; Xue, Jiang

    2016-01-01

    Background As a major cause of mortality in neonates, neonatal sepsis is often accompanied by immune dysfunctions, which are frequently caused by dysregulated T cell sub-populations. The role of regulatory B cells in neonatal sepsis, however, remains unknown. Therefore, this study investigated the percentage and functional variation of CD19+CD24hiCD38hi regulatory B cells in peripheral blood of neonatal sepsis patients in an attempt to elucidate the role of these regulatory B cells in pathogenesis of sepsis. Material/Methods Flow cytometry was used to quantify the percentage of CD19+CD24hiCD38hi regulatory B cells from peripheral blood samples. The correlation between B cell percentage and C reactive protein (CRP) level was analyzed. Secretion level of interleukin-10 (IL-10) and effects on the proliferation of naïve CD4+ T cells were further analyzed. Results The percentage of CD19+CD24hiCD38hi regulatory B cells in neonatal sepsis patients was significantly higher compared to healthy controls (p<0.05), and was positively correlated with serum CRP level. The percentage of IL-10+ CD19+CD24hiCD38hi regulatory B cells was also higher in sepsis patients, and also had more potent inhibition on naïve CD4+ T cells (p<0.01). Conclusions The elevation of CD19+CD24hiCD38hi regulatory B cells in neonatal sepsis can inhibit body immune function and thus may participate in the pathogenesis of sepsis. PMID:27389933

  7. Selective Expansion of Allogeneic Regulatory T Cells by Hepatic Stellate Cells: Role of Endotoxin and Implications for Allograft Tolerance

    PubMed Central

    Dangi, Anil; Sumpter, Tina L.; Kimura, Shoko; Stolz, Donna B.; Murase, Noriko; Raimondi, Giorgio; Vodovotz, Yoram; Huang, Chao; Thomson, Angus W.; Gandhi, Chandrashekhar R.

    2012-01-01

    Hepatic stellate cells (HSCs) may play an important role in hepatic immune regulation by producing numerous cytokines/chemokines, and expressing Ag-presenting and T cell co-regulatory molecules. Due to disruption of the endothelial barrier during cold-ischemic storage and reperfusion of liver grafts, HSCs can interact directly with cells of the immune system. Endotoxin (LPS), levels of which increase in liver diseases and transplantation, stimulates the synthesis of many mediators by HSCs. We hypothesized that LPS-stimulated HSCs might promote hepatic tolerogenicity by influencing naturally-occurring immunosuppressive CD4+CD25+FoxP3+ regulatory T cells (Tregs). Following their portal venous infusion, allogeneic CD4+ T cells, including Tregs, were found closely associated with HSCs, and this association increased in LPS-treated livers. In vitro, both unstimulated and LPS-stimulated HSCs up-regulated Fas (CD95) expression on conventional CD4+ T cells and induced their apoptosis in a Fas/FasL-dependent manner. By contrast, HSCs induced Treg proliferation, which required cell-cell contact, and was MHC class II-dependent. This effect was augmented when HSCs were pretreated with LPS. LPS increased the expression of MHC class II, CD80 and CD86, and stimulated the production of IL-1α, IL-1β, IL-6, IL-10 and TNFα by HSCs. Interestingly, production of IL-1α, IL-1β, IL-6 and TNFα was strongly inhibited, but that of IL-10 enhanced, in LPS-pretreated HSC/Treg co-cultures. Adoptively transferred allogeneic HSCs migrated to the secondary lymphoid tissues and induced Treg expansion in lymph nodes. These data implicate endotoxins-stimulated HSCs as important immune regulators in liver transplantation by inducing selective expansion of tolerance-promoting Tregs, and reducing inflammation and allo-immunity. PMID:22427640

  8. [Downregulation of proteinase activated receptor 4 inhibits migration of SW620 human colorectal cancer cells].

    PubMed

    Chen, Lihong; Li, Chunchun; Xie, Yuqiong; Ye, Jingjia; Cao, Jiang

    2016-05-01

    Objective To establish the human colorectal cancer cell model SW620/PAR4D with inducible suppression of proteinase activated receptor 4 (PAR4) expression, and investigate the role PAR4 plays in the proliferation and migration of cancer cells. Methods A human colorectal cancer cell line with tetracycline-inducible expression regulatory system, namely SW620/Tet-on, was established; inducible expression lentiviral vector with artificial microRNA targeting PAR4, pLVX-Tight-Puro-PAR4-miR, was constructed and transfected into SW620/Tet-on to make an inducible PAR4-suppressed cell model SW620/PAR4D. Western blotting was used to confirm the suppression of PAR4 expression after the doxycycline (DOX) treatment. CCK-8 assay was used to evaluate the impact of suppressed PAR4 expression on cell proliferation, and wound-healing assay was used to analyze the migration of the cells. Results The SW620/PAR4D cell model was established successfully. Suppression of PAR4 expression by DOX treatment had no significant impact on the growth/proliferation of SW620/PAR4D cells, but markedly inhibited the cell migration. Conclusion Suppression of PAR4 expression has no significant effect on the proliferation of SW620 cells, but can inhibit the migration of the cells. PMID:27126938

  9. VIP contribution to the decidualization program: regulatory T cell recruitment.

    PubMed

    Grasso, Esteban; Paparini, Daniel; Agüero, Mariana; Mor, Gil; Pérez Leirós, Claudia; Ramhorst, Rosanna

    2014-04-01

    During early pregnancy, the human uterus undergoes profound tissue remodeling characterized by leukocyte invasion and production of proinflammatory cytokines, followed by tissue repair and tolerance maintenance induction. Vasoactive intestinal peptide (VIP) is produced by trophoblast cells and modulates the maternal immune response toward a tolerogenic profile. Here, we evaluated the contribution of the VIP/VPAC to endometrial renewal, inducing decidualization and the recruitment of induced regulatory T cells (iTregs) that accompany the implantation period. For that purpose, we used an in vitro model of decidualization with a human endometrial stromal cell line (HESC) stimulated with progesterone (P4) and lipopolysaccharide (LPS) simulating the inflammatory response during implantation and human iTregs (CD4(+)CD25(+)FOXP3(+)) differentiated from naïve T cells obtained from peripheral blood mononuclear cells of fertile women. We observed that VIP and its receptor VPAC1 are constitutively expressed in HESCs and that P4 increased VIP expression. Moreover, in HESC VIP induced expression of RANTES (CCL5), one of the main chemokines involved in T cell recruitment, and this effect is enhanced by the presence of P4 and LPS. Finally, assays of the migration of iTregs toward conditioned media from HESCs revealed that endogenous VIP production induced by P4 and LPS and RANTES production were involved, as anti-RANTES neutralizing Ab or VIP antagonist prevented their migration. We conclude that VIP may have an active role in the decidualization process, thus contributing to recruitment of iTregs toward endometrial stromal cells by increasing RANTES expression in a P4-dependent manner. PMID:24492467

  10. Phenotypical characterization of regulatory T cells in humans and rodents.

    PubMed

    Rodríguez-Perea, A L; Arcia, E D; Rueda, C M; Velilla, P A

    2016-09-01

    Regulatory T cells (Tregs ) constitute a fascinating subpopulation of CD4(+) T cells due to their ability to limit the immune response against self and non-self antigens. Murine models and antibodies directed against surface and intracellular molecules have allowed elucidation of the mechanisms that govern their development and function. However, these markers used to their classification lack of specificity, as they can be expressed by activated T cells. Similarly, there are slight differences between animal models, in steady state and pathological conditions, anatomical localization and strategy of analysis by flow cytometry. Here, we revised the most common markers utilized for Treg typification by flow cytometry such as CD25, forkhead box protein 3 (FoxP3) and CD127, along with our data obtained in different body compartments of humans, mice and rats. Furthermore, we revised and determined the expression of other molecules important for the phenotypical characterization of Treg cells. We draw attention to the drawbacks of those markers used in chronic states of inflammation. However, until a specific marker for the identification of Tregs is discovered, the best combination of markers will depend upon the tissue or the degree of inflammation from which Tregs derive. PMID:27124481

  11. Clinical perspectives for regulatory T cells in transplantation tolerance.

    PubMed

    Hippen, Keli L; Riley, James L; June, Carl H; Blazar, Bruce R

    2011-12-01

    Three main types of CD4+ regulatory T cells can be distinguished based upon whether they express Foxp3 and differentiate naturally in the thymus (natural Tregs) or are induced in the periphery (inducible Tregs); or whether they are FoxP3 negative but secrete IL-10 in response to antigen (Tregulatory type 1, Tr1 cells). Adoptive transfer of each cell type has proven highly effective in mouse models at preventing graft vs. host disease (GVHD) and autoimmunity. Although clinical application was initially hampered by low Treg frequency and unfavorable ex vivo expansion properties, several phase I trials are now being conducted to assess their effect on GVHD following hematopoietic stem cell transplantation (HSCT) and in type I diabetes. Human Treg trials for HSCT recipients have preceded other indications because GVHD onset is precisely known, the time period needed for prevention relatively short, initial efficacy is likely to provide life-long protection, and complications of GVHD can be lethal. This review will summarize the clinical trials conducted to date that have employed Tregs to prevent GVHD following HSCT and discuss recent advances in Treg cellular therapy. PMID:21820917

  12. Ubiquitous points of control over regulatory T cells.

    PubMed

    Pan, Fan; Barbi, Joseph

    2014-06-01

    Posttranslational modification by ubiquitin tagging is crucial for regulating the stability, activity and cellular localization of many target proteins involved in processes including DNA repair, cell cycle progression, protein quality control, and signal transduction. It has long been appreciated that ubiquitin-mediated events are important for certain signaling pathways leading to leukocyte activation and the stimulation of effector function. Now it is clear that the activities of molecules and pathways central to immune regulation are also modified and controlled by ubiquitin tagging. Among the mechanisms of immune control, regulatory T cells (or Tregs) are themselves particularly sensitive to such regulation. E3 ligases and deubiquitinases both influence Tregs through their effects on the signaling pathways pertinent to these cells or through the direct, posttranslational regulation of Foxp3. In this review, we will summarize and discuss several examples of ubiquitin-mediated control over multiple aspects of Treg biology including the generation, function and phenotypic fidelity of these cells. Fully explored and exploited, these potential opportunities for Treg modulation may lead to novel immunotherapies for both positive and negative fine-tuning of immune restraint. PMID:24777637

  13. Inhibition Of Call-Cell Binding By Kipid Assemblies

    DOEpatents

    Nagy, Jon O. , Bargatze, Robert F.

    2003-12-16

    This invention relates generally to the field of therapeutic compounds designed to interfere between the binding of ligands and their receptors on cell surface. More specifically, it provides products and methods for inhibiting cell migration and activation using lipid assemblies with surface recognition elements that are specific for the receptors involved in cell migration and activation.

  14. Cognate interaction with iNKT cells expands IL-10-producing B regulatory cells.

    PubMed

    Vomhof-DeKrey, Emilie E; Yates, Jennifer; Hägglöf, Thomas; Lanthier, Paula; Amiel, Eyal; Veerapen, Natacha; Besra, Gurdyal S; Karlsson, Mikael C I; Leadbetter, Elizabeth A

    2015-10-01

    Successful induction of B-cell activation and memory depends on help from CD4+ T cells. Invariant natural killer T (iNKT) cells (glycolipid-specific, CD1d-restricted innate lymphocytes) provide both cognate (direct) and noncognate (indirect) helper signals to enhance B-cell responses. Both forms of iNKT-cell help induce primary humoral immune responses, but only noncognate iNKT-cell help drives humoral memory and plasma cells. Here, we show that iNKT cognate help for B cells is fundamentally different from the help provided by conventional CD4+ T cells. Cognate iNKT-cell help drives an early, unsustained germinal center B-cell expansion, less reduction of T follicular regulatory cells, an expansion of marginal zone B cells, and early increases in regulatory IL-10-producing B-cell numbers compared with noncognate activation. These results are consistent with a mechanism whereby iNKT cells preferentially provide an innate form of help that does not generate humoral memory and has important implications for the application of glycolipid molecules as vaccine adjuvants. PMID:26392556

  15. Cognate interaction with iNKT cells expands IL-10–producing B regulatory cells

    PubMed Central

    Vomhof-DeKrey, Emilie E.; Yates, Jennifer; Hägglöf, Thomas; Lanthier, Paula; Amiel, Eyal; Veerapen, Natacha; Besra, Gurdyal S.; Karlsson, Mikael C. I.; Leadbetter, Elizabeth A.

    2015-01-01

    Successful induction of B-cell activation and memory depends on help from CD4+ T cells. Invariant natural killer T (iNKT) cells (glycolipid-specific, CD1d-restricted innate lymphocytes) provide both cognate (direct) and noncognate (indirect) helper signals to enhance B-cell responses. Both forms of iNKT-cell help induce primary humoral immune responses, but only noncognate iNKT-cell help drives humoral memory and plasma cells. Here, we show that iNKT cognate help for B cells is fundamentally different from the help provided by conventional CD4+ T cells. Cognate iNKT-cell help drives an early, unsustained germinal center B-cell expansion, less reduction of T follicular regulatory cells, an expansion of marginal zone B cells, and early increases in regulatory IL-10–producing B-cell numbers compared with noncognate activation. These results are consistent with a mechanism whereby iNKT cells preferentially provide an innate form of help that does not generate humoral memory and has important implications for the application of glycolipid molecules as vaccine adjuvants. PMID:26392556

  16. Na+,Cl- cotransport in Ehrlich ascites tumor cells activated during volume regulation (regulatory volume increase).

    PubMed

    Hoffmann, E K; Sjøholm, C; Simonsen, L O

    1983-01-01

    Ehrlich ascites cells were preincubated in hypotonic medium with subsequent restoration of tonicity. After the initial osmotic shrinkage the cells recovered their volume within 5 min with an associated KCl uptake. The volume recovery was inhibited when NO-3 was substituted for Cl-, and when Na+ was replaced by K+, or by choline (at 5 mM external K+). The volume recovery was strongly inhibited by furosemide and bumetanide, but essentially unaffected by DIDS. The net uptake of Cl- was much larger than the value predicted from the conductive Cl- permeability. The undirectional 36Cl flux, which was insensitive to bumetanide under steady-state conditions, was substantially increased during regulatory volume increase, and showed a large bumetanide-sensitive component. During volume recovery the Cl- flux ratio (influx/efflux) for the bumetanide-sensitive component was estimated at 1.85, compatible with a coupled uptake of Na+ and Cl-, or with an uptake via a K+,Na+,2Cl- cotransport system. The latter possibility is unlikely, however, because a net uptake of KCl was found even at low external K+, and because no K+ uptake was found in ouabain-poisoned cells. In the presence of ouabain a bumetanide-sensitive uptake during volume recovery of Na+ and Cl- in nearly equimolar amounts was demonstrated. It is proposed that the primary process during the regulatory volume increase is an activation of an otherwise quiescent, bumetanide-sensitive Na+,Cl- cotransport system with subsequent replacement of Na+ by K+ via the Na+/K+ pump, stimulated by the Na+ influx through the Na+,Cl- cotransport system. PMID:6100866

  17. Vitamin D inhibition of lung adenocarcinoma cell proliferation in vitro.

    PubMed

    Li, Rong; Lou, Yuqing; Zhang, Weiyan; Dong, Qianggang; Han, Baohui

    2014-11-01

    Vitamin D has the capability to inhibit tumor cell proliferation and promote tumor cell apoptosis but whether this mechanism exists in lung adenocarcinoma cells remains to be studied. Our objective is to explore whether vitamin D has the capability to inhibit lung adenocarcinoma cell proliferation and synergize with cisplatin. Our method was to explore the effect of different concentrations of 1,25(OH)2D3 with or without cisplatin on lung adenocarcinoma cells by detecting cell proliferation rates at different time points. 1,25(OH)2D3 was capsulated with nanomaterial before acting on lung adenocarcinoma cells, and cell proliferation rates at different time points were detected with the CCK-8 method. When vitamin D was applied at a concentration of 1 × 10(-7) and 1 × 10(-6) mol/L on A549, PC9, SPC-A1, and H1650 cells for 72 h, no inhibition occurred on cell proliferation. Between the concentrations of 1 × 10(-5) and 0.5 × 10(-5) mol/L, inhibition on cell proliferation increased with drug action time. Between the concentration of 2.5 × 10(-5) and 0.03 × 10(-5) mol/L, inhibition on cell proliferation increased with increasing drug concentration. Analysis using bivariate correlations showed that the correlation coefficient of the proliferation inhibition rate and drug content was 0.580 (p < 0.0001). The correlation coefficient of proliferation inhibition rate and the drug action time was 0.379 (p = 0.01). The combined use of vitamin D and dichlorodiammine-platinum(II) (DDP) significantly increased the inhibition rate on A549 cell proliferation, which peaked after culturing for 96 h (Table 4). Further analysis using bivariate correlations showed that the correlation coefficient between proliferation inhibition rate and DDP concentration was 0.319 (p < 0.0001). The correlation coefficient of the proliferation inhibition rate and vitamin D concentration was 0.269 (p < 0.0001). The correlation coefficient of proliferation inhibition and drug action time was 0.221(p

  18. CD19+CD24hiCD38hiBregs involved in downregulate helper T cells and upregulate regulatory T cells in gastric cancer

    PubMed Central

    Wang, Weiwei; Yuan, Xiangliang; Chen, Hui; Xie, Guohua; Ma, Yanhui; Zheng, Yingxia; Zhou, Yunlan; Shen, Lisong

    2015-01-01

    Regulatory B cells (Bregs) play a critical role in inflammation and autoimmune disease. We characterized the role of Bregs in the progression of gastric cancer. We detected an increase in Bregs producing IL-10 both in peripheral blood mononuclear cells (PBMCs) and in gastric tumors. Multicolor flow cytometry analysis revealed that a subset of CD19+CD24hiCD38hi B cells produces IL-10. Functional studies indicated that increased Bregs do not inhibit the proliferation of CD3+T cells or CD4+ helper T cells (Th cells). However, Bregs do suppress the secretion of IFN-γ and TNF-α by CD4+Th cells. CD19+CD24hiCD38hiBregs were also found to correlate positively with CD4+FoxP3+ regulatory T cells (Tregs). Neutralization experiments showed that Bregs convert CD4+CD25− effector T cells to CD4+FoxP3+Tregs via TGF-β1. Collectively, these findings demonstrate that increased Bregs play a immunosuppressive role in gastric cancer by inhibiting T cells cytokines as well as conversion to Tregs. These results may provide new clues about the underlying mechanisms of immune escape in gastric cancer. PMID:26378021

  19. Reduced Numbers and Impaired Function of Regulatory T Cells in Peripheral Blood of Ischemic Stroke Patients.

    PubMed

    Ruhnau, Johanna; Schulze, Juliane; von Sarnowski, Bettina; Heinrich, Marie; Langner, Sönke; Pötschke, Christian; Wilden, Anika; Kessler, Christof; Bröker, Barbara M; Vogelgesang, Antje; Dressel, Alexander

    2016-01-01

    Background and Purpose. Regulatory T cells (Tregs) have been suggested to modulate stroke-induced immune responses. However, analyses of Tregs in patients and in experimental stroke have yielded contradictory findings. We performed the current study to assess the regulation and function of Tregs in peripheral blood of stroke patients. Age dependent expression of CD39 on Tregs was quantified in mice and men. Methods. Total FoxP3(+) Tregs and CD39(+)FoxP3(+) Tregs were quantified by flow cytometry in controls and stroke patients on admission and on days 1, 3, 5, and 7 thereafter. Treg function was assessed by quantifying the inhibition of activation-induced expression of CD69 and CD154 on T effector cells (Teffs). Results. Total Tregs accounted for 5.0% of CD4(+) T cells in controls and <2.8% in stroke patients on admission. They remained below control values until day 7. CD39(+) Tregs were most strongly reduced in stroke patients. On day 3 the Treg-mediated inhibition of CD154 upregulation on CD4(+) Teff was impaired in stroke patients. CD39 expression on Treg increased with age in peripheral blood of mice and men. Conclusion. We demonstrate a loss of active FoxP3(+)CD39(+) Tregs from stroke patient's peripheral blood. The suppressive Treg function of remaining Tregs is impaired after stroke. PMID:27073295

  20. Reduced Numbers and Impaired Function of Regulatory T Cells in Peripheral Blood of Ischemic Stroke Patients

    PubMed Central

    Ruhnau, Johanna; Schulze, Juliane; von Sarnowski, Bettina; Heinrich, Marie; Langner, Sönke; Wilden, Anika; Kessler, Christof; Bröker, Barbara M.

    2016-01-01

    Background and Purpose. Regulatory T cells (Tregs) have been suggested to modulate stroke-induced immune responses. However, analyses of Tregs in patients and in experimental stroke have yielded contradictory findings. We performed the current study to assess the regulation and function of Tregs in peripheral blood of stroke patients. Age dependent expression of CD39 on Tregs was quantified in mice and men. Methods. Total FoxP3+ Tregs and CD39+FoxP3+ Tregs were quantified by flow cytometry in controls and stroke patients on admission and on days 1, 3, 5, and 7 thereafter. Treg function was assessed by quantifying the inhibition of activation-induced expression of CD69 and CD154 on T effector cells (Teffs). Results. Total Tregs accounted for 5.0% of CD4+ T cells in controls and <2.8% in stroke patients on admission. They remained below control values until day 7. CD39+ Tregs were most strongly reduced in stroke patients. On day 3 the Treg-mediated inhibition of CD154 upregulation on CD4+ Teff was impaired in stroke patients. CD39 expression on Treg increased with age in peripheral blood of mice and men. Conclusion. We demonstrate a loss of active FoxP3+CD39+ Tregs from stroke patient's peripheral blood. The suppressive Treg function of remaining Tregs is impaired after stroke. PMID:27073295

  1. Peripheral blood T Regulatory cell counts may not predict transplant rejection

    PubMed Central

    2010-01-01

    Background Recent evidence shows that allograft survival rates show a positive correlation with the number of circulating T regulatory cells (Tregs). This study investigated both the number and the cytokine profiles exhibited by Foxp3+ Tregs in blood, spleen and lymph nodes of Lewis rat recipients of BN rat cardiac allografts after a single-dose of Rapamycin (RAPA). Results Rats were divided into three groups: control group (containing healthy control and acute rejection group), and recipients treated with a single dose of RAPA on either Day 1 (1D group)or Day 3 (3D group) post-transplant. We analyzed the number of Foxp3+Tregs and the expression of Foxp3 and cytokines in the peripheral blood and the peripheral lymphoid tissues. No difference was found in the numbers of circulating Foxp3+ Tregs between these three groups. RAPA administration significantly increased Foxp3 expression in peripheral lymphoid tissues after a single dose of RAPA on Day 3 post-transplant. Foxp3+Tregs inhibited the activity of effector T cells (Teff) via the secretion of TGF-β1. Conclusion The number of Tregs in the recipient's blood may not be a good predictor of transplant rejection. Foxp3+Tregs inhibit the activity of Teff cells mainly in the peripheral lymphoid tissues. PMID:20633262

  2. Restricted maternal nutrition alters myogenic regulatory factor expression in satellite cells of ovine offspring.

    PubMed

    Raja, J S; Hoffman, M L; Govoni, K E; Zinn, S A; Reed, S A

    2016-07-01

    Poor maternal nutrition inhibits muscle development and postnatal muscle growth. Satellite cells are myogenic precursor cells that contribute to postnatal muscle growth, and their activity can be evaluated by the expression of several transcription factors. Paired-box (Pax)7 is expressed in quiescent and active satellite cells. MyoD is expressed in activated and proliferating satellite cells and myogenin is expressed in terminally differentiating cells. Disruption in the expression pattern or timing of expression of myogenic regulatory factors negatively affects muscle development and growth. We hypothesized that poor maternal nutrition during gestation would alter the in vitro temporal expression of MyoD and myogenin in satellite cells from offspring at birth and 3 months of age. Ewes were fed 100% or 60% of NRC requirements from day 31±1.3 of gestation. Lambs from control-fed (CON) or restricted-fed (RES) ewes were euthanized within 24 h of birth (birth; n=5) or were fed a control diet until 3 months of age (n=5). Satellite cells isolated from the semitendinosus muscle were used for gene expression analysis or cultured for 24, 48 or 72 h and immunostained for Pax7, MyoD or myogenin. Fusion index was calculated from a subset of cells allowed to differentiate. Compared with CON, temporal expression of MyoD and myogenin was altered in cultured satellite cells isolated from RES lambs at birth. The percent of cells expressing MyoD was greater in RES than CON (P=0.03) after 24 h in culture. After 48 h of culture, there was a greater percent of cells expressing myogenin in RES compared with CON (P0.05). In satellite cells from RES lambs at 3 months of age, the percent of cells expressing MyoD and myogenin were greater than CON after 72 h in culture (P<0.05). Fusion index was reduced in RES lambs at 3 months of age compared with CON (P<0.001). Restricted nutrition during gestation alters the temporal expression of myogenic regulatory factors in satellite cells of the

  3. Integrating innate and adaptive immune cells: Mast cells as crossroads between regulatory and effector B and T cells.

    PubMed

    Mekori, Yoseph A; Hershko, Alon Y; Frossi, Barbara; Mion, Francesca; Pucillo, Carlo E

    2016-05-01

    A diversity of immune mechanisms have evolved to protect normal tissues from infection, but from immune damage too. Innate cells, as well as adaptive cells, are critical contributors to the correct development of the immune response and of tissue homeostasis. There is a dynamic "cross-talk" between the innate and adaptive immunomodulatory mechanisms for an integrated control of immune damage as well as the development of the immune response. Mast cells have shown a great plasticity, modifying their behavior at different stages of immune response through interaction with effector and regulatory populations of adaptive immunity. Understanding the interplays among T effectors, regulatory T cells, B cells and regulatory B cells with mast cells will be critical in the future to assist in the development of therapeutic strategies to enhance and synergize physiological immune-modulator and -suppressor elements in the innate and adaptive immune system. PMID:25941086

  4. HDAC5 controls the functions of Foxp3(+) T-regulatory and CD8(+) T cells.

    PubMed

    Xiao, Haiyan; Jiao, Jing; Wang, Liqing; O'Brien, Shaun; Newick, Kheng; Wang, Liang-Chuan S; Falkensammer, Eva; Liu, Yujie; Han, Rongxiang; Kapoor, Veena; Hansen, Finn K; Kurz, Thomas; Hancock, Wayne W; Beier, Ulf H

    2016-05-15

    Histone/protein deacetylases (HDACs) are frequently upregulated in human malignancies and have therefore become therapeutic targets in cancer therapy. However, inhibiting certain HDAC isoforms can have protolerogenic effects on the immune system, which could make it easier for tumor cells to evade the host immune system. Therefore, a better understanding of how each HDAC isoform affects immune biology is needed to develop targeted cancer therapy. Here, we studied the immune phenotype of HDAC5(-/-) mice on a C57BL/6 background. While HDAC5(-/-) mice replicate at expected Mendelian ratios and do not develop overt autoimmune disease, their T-regulatory (Treg) cells show reduced suppressive function in vitro and in vivo. Likewise, CD4(+) T-cells lacking HDAC5 convert poorly to Tregs under appropriately polarizing conditions. To test if this attenuated Treg formation and suppressive function translated into improved anticancer immunity, we inoculated HDAC5(-/-) mice and littermate controls with a lung adenocarcinoma cell line. Cumulatively, lack of HDAC5 did not lead to better anticancer immunity. We found that CD8(+) T cells missing HDAC5 had a reduced ability to produce the cytokine, IFN-γ, in vitro and in vivo, which may offset the benefit of weakened Treg function and formation. Taken together, targeting HDAC5 weakens suppressive function and de-novo induction of Tregs, but also reduces the ability of CD8(+) T cells to produce IFN-γ. PMID:26704363

  5. Isoliquiritigenin (ISL) inhibits ErbB3 signaling in prostate cancer cells.

    PubMed

    Jung, Jae In; Chung, Eunkyung; Seon, Mi Ra; Shin, Hyun-Kyung; Kim, Eun Ji; Lim, Soon Sung; Chung, Won-Yoon; Park, Kwang-Kyun; Park, Jung Han Yoon

    2006-01-01

    Isoliquiritigenin (ISL), a flavonoid found in licorice, shallot, and bean sprouts, has been identified as a potent anti-tumor promoting agent. We previously demonstrated that ISL reduces cell proliferation and induces apoptosis in DU145 human prostate cancer cells and MAT-LyLu (MLL) rat prostate cancer cells. Overexpression of members of the ErbB receptor family is a frequently observed event in several human cancers, and ErbB receptors currently constitute the primary targets of anticancer strategies. In order to elucidate the mechanisms underlying the ISL regulation of prostate cancer cell proliferation, the present study attempted to determine whether ISL inhibits heregulin (HRG)-beta-induced ErbB3 signaling. DU145 and MLL cells were cultured in serum-free medium with ISL and/or HRG-beta. Exogenous HRG-beta alone was shown to effect an increase in the numbers of viable cells, whereas HRG-beta did not counteract the ISL-induced growth inhibition. ISL reduced the protein and mRNA levels of ErbB3 in a dose-dependent manner, but exerted no effect on HRG protein levels. Immunoprecipitation/Western blot studies indicated that ISL inhibited the HRG-beta-induced tyrosine phosphorylation of ErbB3, the recruitment of the p85 regulatory subunit of phosphatidylinositol 3-kinase (PI3K) to ErbB3, and Akt phosphorylation in DU145 cells. These results indicate that ISL inhibits the proliferation of prostate cancer cells, at least in part, via the inhibition of ErbB3 signaling and the PI3K/Akt pathway. PMID:17473376

  6. Anti-TNF drives regulatory T cell expansion by paradoxically promoting membrane TNF-TNF-RII binding in rheumatoid arthritis.

    PubMed

    Nguyen, Dao Xuan; Ehrenstein, Michael R

    2016-06-27

    The interplay between inflammatory and regulatory pathways orchestrates an effective immune response that provides protection from pathogens while limiting injury to host tissue. Tumor necrosis factor (TNF) is a pivotal inflammatory cytokine, but there is conflicting evidence as to whether it boosts or inhibits regulatory T cells (T reg cells). In this study, we show that the therapeutic anti-TNF antibody adalimumab, but not the soluble TNF receptor etanercept, paradoxically promoted the interaction between monocytes and T reg cells isolated from patients with rheumatoid arthritis (RA). Adalimumab bound to monocyte membrane TNF from RA patients and unexpectedly enhanced its expression and its binding to TNF-RII expressed on T reg cells. As a consequence, adalimumab expanded functional Foxp3(+) T reg cells equipped to suppress Th17 cells through an IL-2/STAT5-dependent mechanism. Our data not only highlight the beneficial effect of membrane TNF on T reg cell numbers during chronic inflammation, but in addition reveal how a therapeutic antibody that is thought to act by simply blocking its target can enhance the regulatory properties of this proinflammatory cytokine. PMID:27270893

  7. The Importance of the Nurse Cells and Regulatory Cells in the Control of T Lymphocyte Responses

    PubMed Central

    Reyes García, María Guadalupe; García Tamayo, Fernando

    2013-01-01

    T lymphocytes from the immune system are bone marrow-derived cells whose development and activities are carefully supervised by two sets of accessory cells. In the thymus, the immature young T lymphocytes are engulfed by epithelial “nurse cells” and retained in vacuoles, where most of them (95%) are negatively selected and removed when they have an incomplete development or express high affinity autoreactive receptors. The mature T lymphocytes that survive to this selection process leave the thymus and are controlled in the periphery by another subpopulation of accessory cells called “regulatory cells,” which reduce any excessive immune response and the risk of collateral injuries to healthy tissues. By different times and procedures, nurse cells and regulatory cells control both the development and the functions of T lymphocyte subpopulations. Disorders in the T lymphocytes development and migration have been observed in some parasitic diseases, which disrupt the thymic microenvironment of nurse cells. In other cases, parasites stimulate rather than depress the functions of regulatory T cells decreasing T-mediated host damages. This paper is a short review regarding some features of these accessory cells and their main interactions with T immature and mature lymphocytes. The modulatory role that neurotransmitters and hormones play in these interactions is also revised. PMID:23509712

  8. A limited role for regulatory T cells in post-ischemic neovascularization.

    PubMed

    Hellingman, A A; van der Vlugt, L E P M; Lijkwan, M A; Bastiaansen, A J N M; Sparwasser, T; Smits, H H; Hamming, J F; Quax, P H A

    2012-02-01

    Recently, it was demonstrated that arteriogenesis is enhanced in mice deficient in regulatory T cells (CD4(+) CD25(+) FoxP3(+) T cell), which can suppress effector T cell responses. The present study investigates the effects of these regulatory T cells on arteriogenesis in more detail by either specific expanding or depleting regulatory T cells. Hind limb ischemia was induced by electro-coagulation of the femoral artery in mice. Regulatory T cells were either expanded by injecting mice with a complex of interleukin (IL)-2 with the IL-2 monoclonal antibody JES6-1, or depleted by anti-CD25 antibody or diphtheria toxin injections in DEREG mice (depletion of regulatory T cells). Blood flow restoration was monitored using laser Doppler perfusion imaging. Collateral arteries were visualized by immunohistochemistry. Regulatory T cell expansion led to a moderate though significant suppression of blood flow restoration after ischemia induction. Surprisingly, depletion of regulatory T cells resulted in minor increase on blood flow recovery. However, collateral and capillary densities in the post-ischemic skeletal muscle were significantly increased in DEREG mice depleted for regulatory T cells. The presence of regulatory T cells after ischemia induction when analysed in non-depleted DEREG mice could be demonstrated by green fluorescent protein staining only in lymph nodes in the ischemic area, and not in the ischemic muscle tissue. The current study demonstrates that, even under conditions of major changes in regulatory T cell content, the contribution of regulatory T cells to the regulation of the arteriogenic response is only moderate. PMID:21426486

  9. A limited role for regulatory T cells in post-ischemic neovascularization

    PubMed Central

    Hellingman, AA; van der Vlugt, LEPM; Lijkwan, MA; Bastiaansen, AJNM; Sparwasser, T; Smits, HH; Hamming, JF; Quax, PHA

    2012-01-01

    Abstract Recently, it was demonstrated that arteriogenesis is enhanced in mice deficient in regulatory T cells (CD4+CD25+FoxP3+ T cell), which can suppress effector T cell responses. The present study investigates the effects of these regulatory T cells on arteriogenesis in more detail by either specific expanding or depleting regulatory T cells. Hind limb ischemia was induced by electro-coagulation of the femoral artery in mice. Regulatory T cells were either expanded by injecting mice with a complex of interleukin (IL)-2 with the IL-2 monoclonal antibody JES6–1, or depleted by anti-CD25 antibody or diphtheria toxin injections in DEREG mice (depletion of regulatory T cells). Blood flow restoration was monitored using laser Doppler perfusion imaging. Collateral arteries were visualized by immunohistochemistry. Regulatory T cell expansion led to a moderate though significant suppression of blood flow restoration after ischemia induction. Surprisingly, depletion of regulatory T cells resulted in minor increase on blood flow recovery. However, collateral and capillary densities in the post-ischemic skeletal muscle were significantly increased in DEREG mice depleted for regulatory T cells. The presence of regulatory T cells after ischemia induction when analysed in non-depleted DEREG mice could be demonstrated by green fluorescent protein staining only in lymph nodes in the ischemic area, and not in the ischemic muscle tissue. The current study demonstrates that, even under conditions of major changes in regulatory T cell content, the contribution of regulatory T cells to the regulation of the arteriogenic response is only moderate. PMID:21426486

  10. Influence of Dietary Components on Regulatory T Cells

    PubMed Central

    Issazadeh-Navikas, Shohreh; Teimer, Roman; Bockermann, Robert

    2012-01-01

    Common dietary components including vitamins A and D, omega-3 and probiotics are now widely accepted to be essential to protect against many diseases with an inflammatory nature. On the other hand, high-fat diets are documented to exert multiple deleterious effects, including fatty liver diseases. Here we discuss the effect of dietary components on regulatory T cell (Treg) homeostasis, a central element of the immune system to prevent chronic tissue inflammation. Accordingly, evidence on the impact of dietary components on diseases in which Tregs play an influential role will be discussed. We will review chronic tissue-specific autoimmune and inflammatory conditions such as inflammatory bowel disease, type 1 diabetes mellitus, multiple sclerosis, rheumatoid arthritis and allergies among chronic diseases where dietary factors could have a direct influence via modulation of Tregs homeostasis and functions. PMID:22113499

  11. The role of regulatory T cells in cancer immunology

    PubMed Central

    Whiteside, Theresa L

    2015-01-01

    Regulatory T cells (Treg) are generally considered to be significant contributors to tumor escape from the host immune system. Emerging evidence suggests, however, that in some human cancers, Treg are necessary to control chronic inflammation, prevent tissue damage, and limit inflammation-associated cancer development. The dual role of Treg in cancer and underpinnings of Treg diversity are not well understood. This review attempts to provide insights into the importance of Treg subsets in cancer development and its progression. It also considers the role of Treg as potential biomarkers of clinical outcome in cancer. The strategies for monitoring Treg in cancer patients are discussed as is the need for caution in the use of therapies which indiscriminately ablate Treg. A greater understanding of molecular pathways operating in various tumor microenvironments is necessary for defining the Treg impact on cancer and for selecting immunotherapies targeting Treg.

  12. Rationally designed logic integration of regulatory signals in mammalian cells

    NASA Astrophysics Data System (ADS)

    Leisner, Madeleine; Bleris, Leonidas; Lohmueller, Jason; Xie, Zhen; Benenson, Yaakov

    2010-09-01

    Molecular-level information processing is essential for `smart' in vivo nanosystems. Natural molecular computing, such as the regulation of messenger RNA (mRNA) synthesis by special proteins called transcription factors, has inspired engineered systems that can control the levels of mRNA with certain combinations of transcription factors. Here, we show an alternative approach to achieving general-purpose control of mRNA and protein levels by logic integration of transcription factor input signals in mammalian cells. The transcription factors regulate synthetic genes coding for small regulatory RNAs (called microRNAs), which, in turn, control the mRNA of interest (the output) via an RNA interference pathway. The simplicity of these modular interactions makes it possible, in theory, to implement any arbitrary logic relation between the transcription factors and the output. We construct, test and optimize increasingly complex circuits with up to three transcription factor inputs, establishing a platform for in vivo molecular computing.

  13. Bartonella henselae inhibits apoptosis in Mono Mac 6 cells.

    PubMed

    Kempf, Volkhard A J; Schairer, Annette; Neumann, Diana; Grassl, Guntram A; Lauber, Kirsten; Lebiedziejewski, Maria; Schaller, Martin; Kyme, Pierre; Wesselborg, Sebastian; Autenrieth, Ingo B

    2005-01-01

    Bartonella henselae causes the vasculoproliferative disorders bacillary angiomatosis and peliosis probably resulting from the release of vasculoendothelial growth factor (VEGF) from infected epithelial or monocytic host cells. Here we demonstrate that B. henselae in addition to VEGF induction was also capable of inhibiting the endogenous sucide programme of monocytic host cells. Our results show that B. henselae inhibits pyrrolidine dithiocarbamate (PDTC)-induced apoptosis in Mono Mac 6 cells. B. henselae was observed to be present in a vacuolic compartment of Mono Mac 6 cells. Direct contact of B. henselae with Mono Mac 6 cells was crucial for inhibition of apoptosis as shown by the use of a two-chamber model. Inhibition of apoptosis was paralleled by diminished caspase-3 activity which was significantly reduced in PDTC-stimulated and B. henselae-infected cells. The anti-apoptotic effect of B. henselae was accompanied by (i) the activation of the transcription factor NF-kappaB and (ii) the induction of cellular inhibitor of apoptosis proteins-1 and -2 (cIAP-1, -2). Our results suggest a new synergistic mechanism in B. henselae pathogenicity by (i) inhibition of host cell apoptosis via activation of NF-kappaB and (ii) induction of host cell VEGF secretion. PMID:15617526

  14. HIV-specific regulatory T cells are associated with higher CD4 cell counts in primary infection

    PubMed Central

    Kared, Hassen; Lelièvre, Jean-Daniel; Donkova-Petrini, Vladimira; Aouba, Albertine; Melica, Giovanna; Balbo, Michèle; Weiss, Laurence; Lévy, Yves

    2008-01-01

    Objective Expansion of Regulatory T (Treg) cells has been described in chronically HIV-infected subjects. We investigated whether HIV-suppressive Treg could be detected during primary HIV infection (PHI). Methods Seventeen patients diagnosed early after PHI (median: 13 days; 1–55) were studied. Median CD4 cell count was 480 cells/μl (33–1306) and plasma HIV RNA levels ranged between 3.3 to 5.7 log10 cp/mL. Suppressive capacity of blood purified CD4+CD25+ was evaluated in a co-culture assay. Fox-p3, IL-2 and IL-10 were quantified by RT-PCR and intra-cellular staining of ex vivo and activated CD4+CD25high T cells. Results The frequency of CD4+CD127lowCD25high T cells among CD4 T cells was lower in PHI compared to chronic patients (n=19). They exhibited a phenotype of memory T cells and expressed constitutively FoxP3. Similarly to chronic patients, Treg from PHI patients inhibited the proliferation of PPD and HIV p24 activated CD4+CD25− T cells. CD4+CD25high T cells from PHI patients responded specifically to p24 stimulation by expressing IL-10. In untreated PHI patients, the frequency, as well as HIV-specific activity of Treg decreased during a 24-month follow up. A positive correlation between percentages of Treg and both CD4 cell counts and the magnitude of p24-specific suppressive activity at diagnosis of PHI was found. Conclusions Our data showed that HIV drives Treg since PHI and that these cells persist throughout the course of the infection. A correlation between the frequency of Treg and CD4 T cell counts suggest that these cells may impact on the immune activation set point at PHI diagnosis. PMID:19005268

  15. Thymoquinone Inhibits Escherichia coli ATP Synthase and Cell Growth

    PubMed Central

    Ahmad, Zulfiqar; Laughlin, Thomas F.; Kady, Ismail O.

    2015-01-01

    We examined the thymoquinone induced inhibition of purified F1 or membrane bound F1FO E. coli ATP synthase. Both purified F1 and membrane bound F1FO were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F1Fo and purified F1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase. PMID:25996607

  16. Combined MET inhibition and topoisomerase I inhibition block cell growth of small cell lung cancer.

    PubMed

    Rolle, Cleo E; Kanteti, Rajani; Surati, Mosmi; Nandi, Suvobroto; Dhanasingh, Immanuel; Yala, Soheil; Tretiakova, Maria; Arif, Qudsia; Hembrough, Todd; Brand, Toni M; Wheeler, Deric L; Husain, Aliya N; Vokes, Everett E; Bharti, Ajit; Salgia, Ravi

    2014-03-01

    Small cell lung cancer (SCLC) is a devastating disease, and current therapies have not greatly improved the 5-year survival rates. Topoisomerase (Top) inhibition is a treatment modality for SCLC; however, the response is short lived. Consequently, our research has focused on improving SCLC therapeutics through the identification of novel targets. Previously, we identified MNNG HOS transforming gene (MET) to be overexpressed and functional in SCLC. Herein, we investigated the therapeutic potential of combinatorial targeting of MET using SU11274 and Top1 using 7-ethyl-10-hydroxycamptothecin (SN-38). MET and TOP1 gene copy numbers and protein expression were determined in 29 patients with limited (n = 11) and extensive (n = 18) disease. MET gene copy number was significantly increased (>6 copies) in extensive disease compared with limited disease (P = 0.015). Similar TOP1 gene copy numbers were detected in limited and extensive disease. Immunohistochemical staining revealed a significantly higher Top1 nuclear expression in extensive (0.93) versus limited (0.15) disease (P = 0.04). Interestingly, a significant positive correlation was detected between MET gene copy number and Top1 nuclear expression (r = 0.5). In vitro stimulation of H82 cells revealed hepatocyte growth factor (HGF)-induced nuclear colocalization of p-MET and Top1. Furthermore, activation of the HGF/MET axis enhanced Top1 activity, which was abrogated by SU11274. Combination of SN-38 with SU11274 dramatically decreased SCLC growth as compared with either drug alone. Collectively, these findings suggest that the combinatorial inhibition of MET and Top1 is a potentially efficacious treatment strategy for SCLC. PMID:24327519

  17. Roles of regulatory T cells in cancer immunity.

    PubMed

    Takeuchi, Yoshiko; Nishikawa, Hiroyoshi

    2016-08-01

    CD4(+) regulatory T cells (Tregs) expressing the transcription factor FoxP3 are highly immune suppressive and play central roles in the maintenance of self-tolerance and immune homeostasis, yet in malignant tumors they promote tumor progression by suppressing effective antitumor immunity. Indeed, higher infiltration by Tregs is observed in tumor tissues, and their depletion augments antitumor immune responses in animal models. Additionally, increased numbers of Tregs and, in particular, decreased ratios of CD8(+) T cells to Tregs among tumor-infiltrating lymphocytes are correlated with poor prognosis in various types of human cancers. The recent success of cancer immunotherapy represented by immune checkpoint blockade has provided a new insight in cancer treatment, yet more than half of the treated patients did not experience clinical benefits. Identifying biomarkers that predict clinical responses and developing novel immunotherapies are therefore urgently required. Cancer patients whose tumors contain a large number of neoantigens stemming from gene mutations, which have not been previously recognized by the immune system, provoke strong antitumor T-cell responses associated with clinical responses following immune checkpoint blockade, depending on the resistance to Treg-mediated suppression. Thus, integration of a strategy restricting Treg-mediated immune suppression may expand the therapeutic spectrum of cancer immunotherapy towards patients with a lower number of neoantigens. In this review, we address the current understanding of Treg-mediated immune suppressive mechanisms in cancer, the involvement of Tregs in cancer immunotherapy, and strategies for effective and tolerable Treg-targeted therapy. PMID:27160722

  18. T regulatory cells and the immune aging process

    PubMed Central

    Jagger, Ann Titi; Shimojima, Yasuhiro; Goronzy, Jorg J.; Weyand, Cornelia M.

    2016-01-01

    Constant exposure to new and persisting antigens and the need to replace cellular attrition with newly build cells lead to profound remodeling of the immune system during the second half of life. The impact of the immunosenescence process varies amongst the different functional subsets represented within the immune system, and emerging data suggest that progressive aging significantly affects frequencies, subset distribution and functional competence of regulatory T cells (Treg). Given the central role of Treg cells in immune homeostasis, age-related loss of Treg function would be predicted to render the host susceptible to excessive immunity, encountered in elderly humans as a syndrome of chronic-smoldering inflammation. Conversely, age-dependent gain of Treg activity would expose the host to greater risk of immune failure, such as the rising risk of malignancies and infections in the aging population. Emerging data suggest that some Treg populations, specifically naturally occurring Tregs (nTreg), seem to accumulate with advancing age, whereas inducible Tregs (iTreg) appear to be less available in the older host. More studies are necessary to elucidate functional competence of old Tregs, with emphasis on comparing efficacy of young on old Tregs for defined functional domains. Mechanisms of declining Treg inducibility are not understood, but may provide an opportunity for targeted immunomodulation in the elderly. On the horizon is the potential to develop novel therapeutic interventions that target Tregs to make the elderly more efficient in fighting cancers and infections and dampen the risk for senescence-associated inflammation. PMID:24296590

  19. Ubiquitous Points of Control over Regulatory T cells

    PubMed Central

    Pan, Fan; Barbi, Joseph

    2014-01-01

    Posttranslational modification by ubiquitin tagging is crucial for regulating the stability, activity and cellular localization of many target proteins and processes including DNA repair, cell cycle progression, protein quality control and signal transduction. It has long been appreciated that ubiquitin-mediated events are important for certain signaling pathways leading to leukocyte activation and the stimulation of effector function. It is now clear that the activities of molecules and pathways central to immune regulation are also modified and regulated through ubiquitin. Among the mechanisms of immune control, regulatory T cells (or Tregs) are themselves particularly sensitive to such regulation. E3 ligases and deubiquitinases both influence Tregs through their effects on signaling pathways pertinent for these cells or through the direct, posttranslational regulation of Foxp3. In this review we will summarize and discuss several examples of ubiquitin-mediated control over multiple aspects of biology of Tregs including their generation, function and phenotypic fidelity. Fully explored and exploited, these potential opportunities for Treg modulation may lead to novel immunotherapies for both positive and negative fine-tuning of immune restraint. PMID:24777637

  20. HEMA inhibits migration of dental pulp stem cells

    PubMed Central

    Williams, Drake W.; Wu, Hongkun; Oh, Ju-Eun; Fakhar, Camron; Kang, Mo K.; Shin, Ki-Hyuk; Park, No-Hee; Kim, Reuben H.

    2013-01-01

    Objectives Cell migration is an important step in pulpal wound healing. Although components in the resin-based dental materials are known to have adverse effects on pulp wound healing including proliferation and mineralization, their effects on cell migration have been scarcely examined. Here, we investigated effects of 2-Hydroxyethyl methacrylate (HEMA) on migration of dental pulp stem cells (DPSC) in vitro. Methods Cell viability was assessed using MTT assay, and cell migration was evaluated using wound scratch assay and transwell migration assay at non-cytotoxic doses. Western blotting was used to examine pathways associated with migration such as focal adhesion kinase (FAK), mitogen-activated protein kinase (MAPK), and glycogen synthase kinase 3 (GSK3). Results There were no drastic changes in the cell viability below 3mM HEMA. When DPSC were treated with HEMA at 0.5, 1.0, and 2.5mM, cell migration was diminished. HEMA-treated DPSC exhibited the loss of phosphorylated focal adhesion kinase (FAK) in a dose-dependent manner. The HEMA-mediated inhibition of cell migration was associated with phosphorylation of p38 but not GSK3, ERK or JNK pathways. When we inhibited the p38 signaling pathway using a p38 inhibitor, migration of DPSC was suppressed. Conclusion HEMA inhibits migration of dental pulp cells in vitro, suggesting that poor pulpal wound healing under resin-based dental materials may be due, in part, to inhibition of cell migration by HEMA. PMID:23953290

  1. IL-9 contributes to immunosuppression mediated by regulatory T cells and mast cells in B-cell non-hodgkin's lymphoma.

    PubMed

    Feng, Li-Li; Gao, Jun-Ming; Li, Pei-Pei; Wang, Xin

    2011-12-01

    It has been known that regulatory T (Treg) cells and mast cells (MCs) are involved in tumor immunity regulation, but the exact roles and mechanisms of Treg cells and MCs in B-cell non-Hodgkin's lymphoma (NHL) are incompletely defined. In the present study, we found that the number of Foxp3(+) Treg cells and CD117(+) MCs increased in B-cell NHL patients. Concomitantly, a high level of interleukin (IL)-9 was observed in the sera from B-cell NHL patients. Neutralizing IL-9 significantly inhibited tumor growth in the lymphoma model of murine, and this process was associated with down-regulation of Treg cells and MCs. Furthermore, IL-9 was also demonstrated to induce expression of MC-related genes and proliferation of MCs from the bone marrow stem cells. Collectively, our results indicate that Treg cell and MCs are involved in immunosuppression in B-cell NHL, and IL-9 is a key mediator of Treg cells and MCs in that process. These findings provide novel insight for the pathogenesis and possible therapeutic strategy of B-cell NHL. PMID:21898141

  2. Mast cells counteract regulatory T-cell suppression through interleukin-6 and OX40/OX40L axis toward Th17-cell differentiation.

    PubMed

    Piconese, Silvia; Gri, Giorgia; Tripodo, Claudio; Musio, Silvia; Gorzanelli, Andrea; Frossi, Barbara; Pedotti, Rosetta; Pucillo, Carlo E; Colombo, Mario P

    2009-09-24

    The development of inflammatory diseases implies inactivation of regulatory T (Treg) cells through mechanisms that still are largely unknown. Here we showed that mast cells (MCs), an early source of inflammatory mediators, are able to counteract Treg inhibition over effector T cells. To gain insight into the molecules involved in their interplay, we set up an in vitro system in which all 3 cellular components were put in contact. Reversal of Treg suppression required T cell-derived interleukin-6 (IL-6) and the OX40/OX40L axis. In the presence of activated MCs, concomitant abundance of IL-6 and paucity of Th1/Th2 cytokines skewed Tregs and effector T cells into IL-17-producing T cells (Th17). In vivo analysis of lymph nodes hosting T-cell priming in experimental autoimmune encephalomyelitis revealed activated MCs, Tregs, and Th17 cells displaying tight spatial interactions, further supporting the occurrence of an MC-mediated inhibition of Treg suppression in the establishment of Th17-mediated inflammatory responses. PMID:19643985

  3. Treating arthritis by immunomodulation: is there a role for regulatory T cells?

    PubMed Central

    van Wijk, Femke; Roord, Sarah T.; Albani, Salvatore; Prakken, Berent J.

    2010-01-01

    The discovery of regulatory T cells almost 15 years ago initiated a new and exciting research area. The growing evidence for a critical role of these cells in controlling autoimmune responses has raised expectations for therapeutic application of regulatory T cells in patients with autoimmune arthritis. Here, we review recent studies investigating the presence, phenotype and function of these cells in patients with RA and juvenile idiopathic arthritis (JIA) and consider their therapeutic potential. Both direct and indirect methods to target these cells will be discussed. Arguably, a therapeutic approach that combines multiple regulatory T-cell-enhancing strategies could be most successful for clinical application. PMID:20463189

  4. Inhibition of PKR protects against tunicamycin-induced apoptosis in neuroblastoma cells.

    PubMed

    Vaughn, Lauren S; Snee, Brittany; Patel, Rekha C

    2014-02-15

    Endoplasmic reticulum (ER) dysfunction is thought to play a significant role in several neurological disorders, including Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, amyotrophic lateral sclerosis, cerebral ischemia, and the prion diseases. ER dysfunction can be mimicked by cellular stress signals such as disruption of calcium homeostasis, inhibition of protein glycosylation, and reduction of disulfide bonds, which results in accumulation of misfolded proteins in the ER and leads to cell death by apoptosis. Tunicamycin, which is an inhibitor of protein glycosylation, induces ER stress and apoptosis. In this study, we examined the involvement of double stranded (ds) RNA-activated protein kinase PKR in tunicamycin-induced apoptosis. We used overexpression of the trans-dominant negative, catalytically inactive mutant K296R to inhibit PKR activity in neuroblastoma cells. We demonstrate that inhibition of PKR activation in response to tunicamycin protects neuronal cells from undergoing apoptosis. Furthermore, K296R overexpressing cells show defective PKR activation, delayed eIF2α phosphorylation, dramatically delayed ATF4 expression. In addition, both caspase-3 activation and C/EBP homologous protein (CHOP, also known as GADD153) induction, which are markers of apoptotic cells, are absent from K296R overexpression cells in response to tunicamycin. These results establish that PKR activation plays a major regulatory role in induction of apoptosis in response to ER stress and indicates the potential of PKR as possible target for neuroprotective therapeutics. PMID:24334130

  5. Blue light inhibits proliferation of melanoma cells

    NASA Astrophysics Data System (ADS)

    Becker, Anja; Distler, Elisabeth; Klapczynski, Anna; Arpino, Fabiola; Kuch, Natalia; Simon-Keller, Katja; Sticht, Carsten; van Abeelen, Frank A.; Gretz, Norbert; Oversluizen, Gerrit

    2016-03-01

    Photobiomodulation with blue light is used for several treatment paradigms such as neonatal jaundice, psoriasis and back pain. However, little is known about possible side effects concerning melanoma cells in the skin. The aim of this study was to assess the safety of blue LED irradiation with respect to proliferation of melanoma cells. For that purpose we used the human malignant melanoma cell line SK-MEL28. Cell proliferation was decreased in blue light irradiated cells where the effect size depended on light irradiation dosage. Furthermore, with a repeated irradiation of the melanoma cells on two consecutive days the effect could be intensified. Fluorescence-activated cell sorting with Annexin V and Propidium iodide labeling did not show a higher number of dead cells after blue light irradiation compared to non-irradiated cells. Gene expression analysis revealed down-regulated genes in pathways connected to anti-inflammatory response, like B cell signaling and phagosome. Most prominent pathways with up-regulation of genes were cytochrome P450, steroid hormone biosynthesis. Furthermore, even though cells showed a decrease in proliferation, genes connected to the cell cycle were up-regulated after 24h. This result is concordant with XTT test 48h after irradiation, where irradiated cells showed the same proliferation as the no light negative control. In summary, proliferation of melanoma cells can be decreased using blue light irradiation. Nevertheless, the gene expression analysis has to be further evaluated and more studies, such as in-vivo experiments, are warranted to further assess the safety of blue light treatment.

  6. Binding immunoglobulin protein-treated peripheral blood monocyte-derived dendritic cells are refractory to maturation and induce regulatory T-cell development.

    PubMed

    Corrigall, Valerie M; Vittecoq, Olivier; Panayi, Gabriel S

    2009-10-01

    Binding immunoglobulin protein (BiP) has been shown previously to have immunomodulatory functions. Herein we investigated whether BiP could affect the differentiation of monocytes into dendritic cells (DCs) and thence the development of regulatory T cells. Peripheral blood monocyte-derived DCs were matured with lipopolysaccharide in the presence or absence of BiP. DC development and T-cell changes were monitored by flow cytometry and regulatory T-cell function was measured by uptake of tritiated thymidine. More BiP-treated DCs (DC((BiP))s) expressed amounts of intracellular indoleamine 2,3-dioxygenase (IDO) and cell surface leucocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1), retained CD14 expression but down-regulated expression of human leucocyte antigen (HLA)-DR and CD86, and produced copious amounts of interleukin (IL)-10, when compared with control DCs. T cells co-cultured with DC((BiP))s developed regulatory function with increased surface expression of CD4(+) CD25(hi) CD27(hi) but with no concomitant increase in forkhead box P3 (Foxp3). These T cells also showed significantly higher levels of intracellular cytotoxic T-lymphocyte antigen (CTLA)-4. The latter could be inhibited by the presence of the IDO inhibitor 1 methyl tryptophan. The addition of neutralizing anti-IL-10 antibody or the specific mitogen-activated protein kinase (MAPK) p38 inhibitor SB203580 reversed the inhibition of DC differentiation by BiP. In conclusion, BiP is an immunomodulator able to arrest inflammation through induction of tolerogenic DCs and subsequent generation of T regulatory cells. PMID:19740378

  7. Inhibition of cyclooxygenase (COX)-2 affects endothelial progenitor cell proliferation

    SciTech Connect

    Colleselli, Daniela; Bijuklic, Klaudija; Mosheimer, Birgit A.; Kaehler, Christian M. . E-mail: C.M.Kaehler@uibk.ac.at

    2006-09-10

    Growing evidence indicates that inducible cyclooxygenase-2 (COX-2) is involved in the pathogenesis of inflammatory disorders and various types of cancer. Endothelial progenitor cells recruited from the bone marrow have been shown to be involved in the formation of new vessels in malignancies and discussed for being a key point in tumour progression and metastasis. However, until now, nothing is known about an interaction between COX and endothelial progenitor cells (EPC). Expression of COX-1 and COX-2 was detected by semiquantitative RT-PCR and Western blot. Proliferation kinetics, cell cycle distribution and rate of apoptosis were analysed by MTT test and FACS analysis. Further analyses revealed an implication of Akt phosphorylation and caspase-3 activation. Both COX-1 and COX-2 expression can be found in bone-marrow-derived endothelial progenitor cells in vitro. COX-2 inhibition leads to a significant reduction in proliferation of endothelial progenitor cells by an increase in apoptosis and cell cycle arrest. COX-2 inhibition leads further to an increased cleavage of caspase-3 protein and inversely to inhibition of Akt activation. Highly proliferating endothelial progenitor cells can be targeted by selective COX-2 inhibition in vitro. These results indicate that upcoming therapy strategies in cancer patients targeting COX-2 may be effective in inhibiting tumour vasculogenesis as well as angiogenic processes.

  8. Kinome Profiling of Regulatory T Cells: A Closer Look into a Complex Intracellular Network

    PubMed Central

    Tuettenberg, Andrea; Hahn, Susanne A.; Mazur, Johanna; Gerhold-Ay, Aslihan; Scholma, Jetse; Marg, Iris; Ulges, Alexander; Satoh, Kazuki; Bopp, Tobias; Joore, Jos; Jonuleit, Helmut

    2016-01-01

    Regulatory T cells (Treg) are essential for T cell homeostasis and maintenance of peripheral tolerance. They prevent activation of auto-reactive T effector cells (Teff) in the context of autoimmunity and allergy. Otherwise, Treg also inhibit effective immune responses against tumors. Besides a number of Treg-associated molecules such as Foxp3, CTLA-4 or GARP, known to play critical roles in Treg differentiation, activation and function, the involvement of additional regulatory elements is suggested. Herein, kinase activities seem to play an important role in Treg fine tuning. Nevertheless, our knowledge regarding the complex intracellular signaling pathways controlling phenotype and function of Treg is still limited and based on single kinase cascades so far. To gain a more comprehensive insight into the pathways determining Treg function we performed kinome profiling using a phosphorylation-based kinome array in human Treg at different activation stages compared to Teff. Here we have determined intriguing quantitative differences in both populations. Resting and activated Treg showed an altered pattern of CD28-dependent kinases as well as of those involved in cell cycle progression. Additionally, significant up-regulation of distinct kinases such as EGFR or CK2 in activated Treg but not in Teff not only resemble data we obtained in previous studies in the murine system but also suggest that those specific molecular activation patterns can be used for definition of the activation and functional state of human Treg. Taken together, detailed investigation of kinome profiles opens the possibility to identify novel molecular mechanisms for a better understanding of Treg biology but also for development of effective immunotherapies against unwanted T cell responses in allergy, autoimmunity and cancer. PMID:26881744

  9. Kinome Profiling of Regulatory T Cells: A Closer Look into a Complex Intracellular Network.

    PubMed

    Tuettenberg, Andrea; Hahn, Susanne A; Mazur, Johanna; Gerhold-Ay, Aslihan; Scholma, Jetse; Marg, Iris; Ulges, Alexander; Satoh, Kazuki; Bopp, Tobias; Joore, Jos; Jonuleit, Helmut

    2016-01-01

    Regulatory T cells (Treg) are essential for T cell homeostasis and maintenance of peripheral tolerance. They prevent activation of auto-reactive T effector cells (Teff) in the context of autoimmunity and allergy. Otherwise, Treg also inhibit effective immune responses against tumors. Besides a number of Treg-associated molecules such as Foxp3, CTLA-4 or GARP, known to play critical roles in Treg differentiation, activation and function, the involvement of additional regulatory elements is suggested. Herein, kinase activities seem to play an important role in Treg fine tuning. Nevertheless, our knowledge regarding the complex intracellular signaling pathways controlling phenotype and function of Treg is still limited and based on single kinase cascades so far. To gain a more comprehensive insight into the pathways determining Treg function we performed kinome profiling using a phosphorylation-based kinome array in human Treg at different activation stages compared to Teff. Here we have determined intriguing quantitative differences in both populations. Resting and activated Treg showed an altered pattern of CD28-dependent kinases as well as of those involved in cell cycle progression. Additionally, significant up-regulation of distinct kinases such as EGFR or CK2 in activated Treg but not in Teff not only resemble data we obtained in previous studies in the murine system but also suggest that those specific molecular activation patterns can be used for definition of the activation and functional state of human Treg. Taken together, detailed investigation of kinome profiles opens the possibility to identify novel molecular mechanisms for a better understanding of Treg biology but also for development of effective immunotherapies against unwanted T cell responses in allergy, autoimmunity and cancer. PMID:26881744

  10. Lithium inhibits tumor lymphangiogenesis and metastasis through the inhibition of TGFBIp expression in cancer cells

    PubMed Central

    Maeng, Yong-Sun; Lee, Rina; Lee, Boram; Choi, Seung-il; Kim, Eung Kweon

    2016-01-01

    Metastasis is the main cause of mortality in cancer patients. Although there are many anti-cancer drugs targeting tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression; in particular, lymphangiogenesis is pivotal for metastasis in cancer. Here we report that lithium inhibits colon cancer metastasis by blocking lymphangiogenesis. Lithium reduces the expression of transforming growth factor-β-induced protein (TGFBIp) in colon cancer cells by inhibiting Smad3 phosphorylation via GSK3β inactivation. Moreover, lithium inhibits lymphatic endothelial cell migration, which is increased upon TGFBIp expression in tumor cells. Lithium had no significant effect on SW620 tumor growth in vitro and in vivo; however, it inhibited lymphangiogenesis in tumors. In tumor xenografts model, lithium was found to prevent metastasis to the lungs, liver, and lymph nodes by inhibiting TGFBIp-induced tumor lymphangiogenesis. Collectively, our findings demonstrate a novel role of lithium in the inhibition of colon cancer metastasis by blocking TGFBIp expression, and thereby TGFBIp-induced lymphangiogenesis, in primary tumors. PMID:26857144

  11. Lithium inhibits tumor lymphangiogenesis and metastasis through the inhibition of TGFBIp expression in cancer cells.

    PubMed

    Maeng, Yong-Sun; Lee, Rina; Lee, Boram; Choi, Seung-Il; Kim, Eung Kweon

    2016-01-01

    Metastasis is the main cause of mortality in cancer patients. Although there are many anti-cancer drugs targeting tumor growth, anti-metastatic agents are rarely developed. Angiogenesis and lymphangiogenesis are crucial for cancer progression; in particular, lymphangiogenesis is pivotal for metastasis in cancer. Here we report that lithium inhibits colon cancer metastasis by blocking lymphangiogenesis. Lithium reduces the expression of transforming growth factor-β-induced protein (TGFBIp) in colon cancer cells by inhibiting Smad3 phosphorylation via GSK3β inactivation. Moreover, lithium inhibits lymphatic endothelial cell migration, which is increased upon TGFBIp expression in tumor cells. Lithium had no significant effect on SW620 tumor growth in vitro and in vivo; however, it inhibited lymphangiogenesis in tumors. In tumor xenografts model, lithium was found to prevent metastasis to the lungs, liver, and lymph nodes by inhibiting TGFBIp-induced tumor lymphangiogenesis. Collectively, our findings demonstrate a novel role of lithium in the inhibition of colon cancer metastasis by blocking TGFBIp expression, and thereby TGFBIp-induced lymphangiogenesis, in primary tumors. PMID:26857144

  12. Ghrelin Inhibits Oligodendrocyte Cell Death by Attenuating Microglial Activation

    PubMed Central

    Lee, Jee Youn

    2014-01-01

    Background Recently, we reported the antiapoptotic effect of ghrelin in spinal cord injury-induced apoptotic cell death of oligodendrocytes. However, how ghrelin inhibits oligodendrocytes apoptosis, is still unknown. Therefore, in the present study, we examined whether ghrelin inhibits microglia activation and thereby inhibits oligodendrocyte apoptosis. Methods Using total cell extracts prepared from BV-2 cells activated by lipopolysaccharide (LPS) with or without ghrelin, the levels of p-p38 phosphor-p38 mitogen-activated protein kinase (p-p38MAPK), phospho-c-Jun N-terminal kinase (pJNK), p-c-Jun, and pro-nerve growth factor (proNGF) were examined by Western blot analysis. Reactive oxygen species (ROS) production was investigated by using dichlorodihydrofluorescein diacetate. To examine the effect of ghrelin on oligodendrocyte cell death, oligodendrocytes were cocultured in transwell chambers of 24-well plates with LPS-stimulated BV-2 cells. After 48 hours incubation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling staining were assessed. Results Ghrelin treatment significantly decreased levels of p-p38MAPK, p-JNK, p-c-Jun, and proNGF in LPS-stimulated BV-2 cells. ROS production increased in LPS-stimulated BV-2 cells was also significantly inhibited by ghrelin treatment. In addition, ghrelin significantly inhibited oligodendrocyte cell death when cocultured with LPS-stimulated BV-2 cells. Conclusion Ghrelin inhibits oligodendrocyte cell death by decreasing proNGF and ROS production as well as p38MAPK and JNK activation in activated microglia as an anti-inflammatory hormone. PMID:25309797

  13. Physical, biologic, and phenotypic properties of natural regulatory cells in murine bone marrow

    SciTech Connect

    Dorshkind, K.; Rosse, C.

    1982-05-01

    A lymphocyte-enriched fraction of murine bone marrow (BML) contains natural regulatory cells (NRC) that can inhibit, on a dose-dependent basis, proliferative and cytotoxic responses to alloantigens in a mixed lymphocyte culture. The objective of this study was to investigate the characteristics of the cells responsible for this phenomenon in CBA mice. Maximal suppression was obtained with BML cells themselves rather than cell products. Light-scatter analysis of NRC on the fluorescence-activated cell sorter demonstrated them to be larger than small lymphocytes, and their sedimentation in discontinuous Percoll gradients showed the cells to be of heterogeneous density. This heterogeneity is further reflected by the fact that both plastic adherent and nonadherent BML are suppressive. NRC must be viable in order to mediate suppression; they are cortisone-resistant and are not affected by doses of gamma irradiation up to 1,000 R. NRC are not T or B lymphocytes or Ia-bearing macrophages. The involvement of mature granulocytes and macrophages in natural suppression is unlikely in that NRC do not bear Fc receptors. Elimination of cells from BML with the natural killer (NK) surface marker Asialo GM1 does not abrogate suppression. NRC are capable of mediating suppression across major and minor histocompatibility complex barriers. While lymphoid cells are prominent in BML, the contamination of this marrow fraction with immature granulocytes and monocytes makes a morphologic identification of NRC difficult. These characteristics are most consistent with NRC begin immature marrow cells of undetermined lineage. The relationship of NRC to naturally occurring marrow suppressor cells described in other systems is not yet clear and awaits experimental clarification.

  14. Selective potentiation of lometrexol growth inhibition by dipyridamole through cell-specific inhibition of hypoxanthine salvage.

    PubMed Central

    Turner, R. N.; Aherne, G. W.; Curtin, N. J.

    1997-01-01

    The novel antifolate lometrexol (5,10-dideazatetrahydrofolate) inhibits de novo purine biosynthesis, and co-incubation with hypoxanthine abolishes its cytotoxicity. The prevention of hypoxanthine rescue from an antipurine antifolate by the nucleoside transport inhibitor dipyridamole was investigated for the first time in nine human and rodent cell lines from seven different tissues of origin. In A549, HeLa and CHO cells, dipyridamole prevented hypoxanthine rescue and so growth was inhibited by the combination of lometrexol, dipyridamole and hypoxanthine, but in HT29, HCT116, KK47, MDA231, CCRF CEM and L1210 cells dipyridamole had no effect and the combination did not inhibit growth. Dipyridamole inhibited hypoxanthine uptake in A549 but not in CCRF CEM cells. Dipyridamole prevented the hypoxanthine-induced repletion of dGTP pools, depleted by lometrexol, in A549 but not in CCRF CEM cells. Thus, the selective growth-inhibitory effect of the combination of lometrexol, dipyridamole and hypoxanthine is apparently due to the dipyridamole sensitivity (ds) or insensitivity (di) of hypoxanthine transport. Both the human and murine leukaemic cells are of the di phenotype. If this reflects the transport phenotype of normal bone marrow it would suggest that the combination of lometrexol, dipyridamole and hypoxanthine might be selectively toxic to certain tumour types and have reduced toxicity to the bone marrow. PMID:9374375

  15. CD4+ T cell anergy prevents autoimmunity and generates regulatory T cell precursors

    PubMed Central

    Kalekar, Lokesh A.; Schmiel, Shirdi E.; Nandiwada, Sarada L.; Lam, Wing Y.; Barsness, Laura O.; Zhang, Na; Stritesky, Gretta L.; Malhotra, Deepali; Pauken, Kristen E.; Linehan, Jonathan L.; O’Sullivan, M. Gerard; Fife, Brian T.; Hogquist, Kristin A.; Jenkins, Marc K.; Mueller, Daniel L.

    2015-01-01

    The role that anergy, an acquired state of T cell functional unresponsiveness, plays in natural peripheral tolerance remains unclear. In this study, we demonstrate that anergy is selectively induced in fetal antigen-specific maternal CD4+ T cells during pregnancy. A naturally occurring subpopulation of anergic polyclonal CD4+ T cells, enriched in self antigen-specific T cell receptors, is also observed in healthy hosts. Neuropilin-1 expression in anergic conventional CD4+ T cells is associated with thymic regulatory T cell (Treg cell)-related gene hypomethylation, and this correlates with their capacity to differentiate into Foxp3+ Treg cells that suppress immunopathology. Thus, our data suggest that not only is anergy induction important in preventing autoimmunity, but it also generates the precursors for peripheral Treg cell differentiation. PMID:26829766

  16. Smooth Muscle Cell-targeted RNA Aptamer Inhibits Neointimal Formation.

    PubMed

    Thiel, William H; Esposito, Carla L; Dickey, David D; Dassie, Justin P; Long, Matthew E; Adam, Joshua; Streeter, Jennifer; Schickling, Brandon; Takapoo, Maysam; Flenker, Katie S; Klesney-Tait, Julia; Franciscis, Vittorio de; Miller, Francis J; Giangrande, Paloma H

    2016-04-01

    Inhibition of vascular smooth muscle cell (VSMC) proliferation by drug eluting stents has markedly reduced intimal hyperplasia and subsequent in-stent restenosis. However, the effects of antiproliferative drugs on endothelial cells (EC) contribute to delayed re-endothelialization and late stent thrombosis. Cell-targeted therapies to inhibit VSMC remodeling while maintaining EC health are necessary to allow vascular healing while preventing restenosis. We describe an RNA aptamer (Apt 14) that functions as a smart drug by preferentially targeting VSMCs as compared to ECs and other myocytes. Furthermore, Apt 14 inhibits phosphatidylinositol 3-kinase/protein kinase-B (PI3K/Akt) and VSMC migration in response to multiple agonists by a mechanism that involves inhibition of platelet-derived growth factor receptor (PDGFR)-β phosphorylation. In a murine model of carotid injury, treatment of vessels with Apt 14 reduces neointimal formation to levels similar to those observed with paclitaxel. Importantly, we confirm that Apt 14 cross-reacts with rodent and human VSMCs, exhibits a half-life of ~300 hours in human serum, and does not elicit immune activation of human peripheral blood mononuclear cells. We describe a VSMC-targeted RNA aptamer that blocks cell migration and inhibits intimal formation. These findings provide the foundation for the translation of cell-targeted RNA therapeutics to vascular disease. PMID:26732878

  17. Caveolin-1 regulates TCR signal strength and regulatory T-cell differentiation into alloreactive T cells.

    PubMed

    Schönle, Anne; Hartl, Frederike A; Mentzel, Jan; Nöltner, Theresa; Rauch, Katharina S; Prestipino, Alessandro; Wohlfeil, Sebastian A; Apostolova, Petya; Hechinger, Anne-Kathrin; Melchinger, Wolfgang; Fehrenbach, Kerstin; Guadamillas, Marta C; Follo, Marie; Prinz, Gabriele; Ruess, Ann-Katrin; Pfeifer, Dietmar; Angel Del Pozo, Miguel; Schmitt-Graeff, Annette; Duyster, Justus; Hippen, Keli I; Blazar, Bruce R; Schachtrup, Kristina; Minguet, Susana; Zeiser, Robert

    2016-04-14

    Caveolin-1 (Cav-1) is a key organizer of membrane specializations and a scaffold protein that regulates signaling in multiple cell types. We found increased Cav-1 expression in human and murine T cells after allogeneic hematopoietic cell transplantation. Indeed, Cav-1(-/-)donor T cells caused less severe acute graft-versus-host disease (GVHD) and yielded higher numbers of regulatory T cells (Tregs) compared with controls. Depletion of Tregs from the graft abrogated this protective effect. Correspondingly, Treg frequencies increased when Cav-1(-/-)T cells were exposed to transforming growth factor-β/T-cell receptor (TCR)/CD28 activation or alloantigen stimulation in vitro compared with wild-type T cells. Mechanistically, we found that the phosphorylation of Cav-1 is dispensable for the control of T-cell fate by using a nonphosphorylatable Cav-1 (Y14F/Y14F) point-mutation variant. Moreover, the close proximity of lymphocyte-specific protein tyrosine kinase (Lck) to the TCR induced by TCR-activation was reduced in Cav-1(-/-)T cells. Therefore, less TCR/Lck clustering results in suboptimal activation of the downstream signaling events, which correlates with the preferential development into a Treg phenotype. Overall, we report a novel role for Cav-1 in TCR/Lck spatial distribution upon TCR triggering, which controls T-cell fate toward a regulatory phenotype. This alteration translated into a significant increase in the frequency of Tregs and reduced GVHD in vivo. PMID:26837700

  18. The Paradox Role of Regulatory T Cells in Ischemic Stroke

    PubMed Central

    Li, Min; Jiang, Yongjun

    2013-01-01

    The underlying mechanism of ischemic stroke is not completely known. Regulatory T cells (Tregs), a subset of T cells, play a pivotal role in the pathophysiological process of ischemic stroke. However, there is also controversy over the role of Tregs in stroke. Hence, the function of Tregs in ischemic stroke has triggered a heated discussion recently. In this paper, we reviewed the current lines of evidence to describe the full view of Tregs in stroke. We would like to introduce the basic concepts of Tregs and then discuss their paradox function in ischemic stroke. On one side, Tregs could protect brain against ischemic injury via modulating the inflammation process. On the other side, they exaggerated the insult by causing microvascular dysfunction. They also interfered with the neurological function recovery. In addition, the reasons for this paradox role would be discussed in the review and the prospective of the clinical application of Tregs was also included. In conclusion, Tregs contributed to the outcome of ischemic stroke, while more lines of evidence are needed to understand how Tregs regulate the immune system and influence the outcome of stroke. PMID:24288462

  19. Inhibition of infectious bursal disease virus by vector delivered SiRNA in cell culture.

    PubMed

    Sahare, Amol Ashok; Bedekar, Megha Kadam; Jain, Sudhir Kumar; Singh, Azad; Singh, Sanjeev; Sarkhel, Bikas Chandra

    2015-01-01

    Infectious Bursal Disease (IBD) is major threat to poultry industry. It causes severe immunosuppression and mortality in chicken generally at 3 to 6 weeks of age. RNA intereference (RNAi) emerges as a potent gene regulatory tool in last few years. The present study was conducted to evaluate the efficiency of RNAi to inhibit the IBD virus (IDBV) replication in-vitro. VP2 gene of virus encodes protein involved in capsid formation, cell entry and induction of protective immune responses against it. Thus, VP2 gene of IBDV is the candidate target for the molecular techniques applied for IBDV detection and inhibition assay. In this study, IBDV was isolated from field cases and confirmed by RT-PCR. The virus was then adapted on chicken embryo fibroblast cells (CEF) in which it showed severe cytopathic effects (CPE). The short hairpin RNA (shRNAs) constructs homologous to the VP2 gene were designed and one, having maximum score and fulfilling maximum Reynolds criteria, was selected for evaluation of effective inhibition. Selected shRNA construct (i.e., VP2-shRNA) was observed to be the most effective for inhibiting VP2 gene expression. Real time PCR analysis was performed to measure the relative expression of VP2 gene in different experimental groups. The VP2 gene was less expressed in virus infected cells co-transfected with VP2-shRNA as compared to mock transfected cells and IBDV+ cells (control) at dose 1.6 µ g. The result showed ∼95% efficient down regulation of VP2 gene mRNA in VP2-shRNA treated cells. These findings suggested that designed shRNA construct achieved high level of inhibition of VP2 gene expression in-vitro. PMID:25153457

  20. Guanine nucleotide-binding regulatory proteins in retinal pigment epithelial cells

    SciTech Connect

    Jiang, Meisheng; Tran, V.T.; Fong, H.K.W. ); Pandey, S. )

    1991-05-01

    The expression of GTP-binding regulatory proteins (G proteins) in retinal pigment epithelial (RPE) cells was analyzed by RNA blot hybridization and cDNA amplification. Both adult and fetal human RPE cells contain mRNA for multiple G protein {alpha} subunits (G{alpha}) including G{sub s}{alpha}, G{sub i-1}{alpha}, G{sub i-2}{alpha}, G{sub i-3}{alpha}, and G{sub z}{alpha} (or G{sub x}{alpha}), where G{sub s} and G{sub i} are proteins that stimulate or inhibit adenylyl cyclase, respectively, and G{sub z} is a protein that may mediate pertussis toxin-insensitive events. Other G{alpha}-related mRNA transcripts were detected in fetal RPE cells by low-stringency hybridization to G{sub i-2}{alpha} and G{sub s}{alpha} protein-coding cDNA probes. The diversity of G proteins in RPE cells was further studied by cDNA amplification with reverse transcriptase and the polymerase chain reaction. This approach revealed that, besides the above mentioned members of the G{alpha} gene family, at least two other G{alpha} subunits are expressed in RPE cells. Human retinal cDNA clones that encode one of the additional G{alpha} subunits were isolated and characterized. The results indicate that this G{alpha} subunit belongs to a separate subfamily of G proteins that may be insensitive to inhibition by pertussis toxin.

  1. Interleukin-2 treatment of tumor patients can expand regulatory T cells

    PubMed Central

    Beyer, Marc

    2012-01-01

    Augmented numbers of regulatory T cells contribute to the overall immunosuppression in tumor patients. Interleukin-2 has been widely used in the clinics in anticancer therapy, yet evidence has accumulated that the major drawback, limiting clinical efficacy, is the expansion of regulatory T cells, which aggravates immunosuppression. PMID:23170272

  2. The Cellular and Molecular Mechanisms of Immuno-Suppression by Human Type 1 Regulatory T Cells

    PubMed Central

    Gregori, Silvia; Goudy, Kevin S.; Roncarolo, Maria Grazia

    2011-01-01

    The immuno-regulatory mechanisms of IL-10-producing type 1 regulatory T (Tr1) cells have been widely studied over the years. However, several recent discoveries have shed new light on the cellular and molecular mechanisms that human Tr1 cells use to control immune responses and induce tolerance. In this review we outline the well known and newly discovered regulatory properties of human Tr1 cells and provide an in-depth comparison of the known suppressor mechanisms of Tr1 cells with FOXP3+ Treg. We also highlight the role that Tr1 cells play in promoting and maintaining tolerance in autoimmunity, allergy, and transplantation. PMID:22566914

  3. Analgesic-antitumor peptide inhibits proliferation and migration of SHG-44 human malignant glioma cells.

    PubMed

    Zhao, Youlong; Cai, Xueting; Ye, Tingmei; Huo, Jiege; Liu, Chao; Zhang, Shuangquan; Cao, Peng

    2011-09-01

    Malignant gliomas, the most common subtype of primary brain tumors, are characterized by high proliferation, great invasion, and neurological destruction and considered to be the deadliest of human cancers. Analgesic-antitumor peptide (AGAP), one of scorpion toxic polypeptides, has been shown to have antitumor activity. Here, we show that recombinant AGAP (rAGAP) not only inhibits the proliferation of gliomas cell SHG-44 and rat glioma cell C6, but also suppresses the migration of SHG-44 cells during wound healing. To explain these phenomena, we find that rAGAP leads to cell cycle of SHG-44 arrested in G1 phase accompanied by suppressing G1 cell cycle regulatory proteins CDK2, CDK6, and p-RB by means of the down-regulated protein expression of p-AKT. Meanwhile, rAGAP significantly decreases the production of NF-κB, BCL-2, p-p38, p-c-Jun, and p-Erk1/2 and further suppresses the activation of VEGF and MMP-9 in SHG-44 cells. These findings suggest rAGAP inhibit proliferation and migration of SHG-44 cells by arresting cell cycle and interfering p-AKT, NF-κB, BCL-2, and MAPK signaling pathways. PMID:21538480

  4. Phenotypic and Functional Analysis of Activated Regulatory T Cells Isolated from Chronic Lymphocytic Choriomeningitis Virus-infected Mice.

    PubMed

    Park, Hyo Jin; Oh, Ji Hoon; Ha, Sang-Jun

    2016-01-01

    Regulatory T (Treg) cells, which express Foxp3 as a transcription factor, are subsets of CD4(+) T cells. Treg cells play crucial roles in immune tolerance and homeostasis maintenance by regulating the immune response. The primary role of Treg cells is to suppress the proliferation of effector T (Teff) cells and the production of cytokines such as IFN-γ, TNF-α, and IL-2. It has been demonstrated that Treg cells' ability to inhibit the function of Teff cells is enhanced during persistent pathogen infection and cancer development. To clarify the function of Treg cells under resting or inflamed conditions, a variety of in vitro suppression assays using mouse or human Treg cells have been devised. The main aim of this study is to develop a method to compare the differences in phenotype and suppressive function between resting and activated Treg cells. To isolate activated Treg cells, mice were infected with lymphocytic choriomeningitis virus (LCMV) clone 13 (CL13), a chronic strain of LCMV. Treg cells isolated from the spleen of LCMV CL13-infected mice exhibited both the activated phenotype and enhanced suppressive activity compared with resting Treg cells isolated from naïve mice. Here, we describe the basic protocol for ex vivo phenotype analysis to distinguish activated Treg cells from resting Treg cells. Furthermore, we describe a protocol for the measurement of the suppressive activity of fully activated Treg cells. PMID:27404802

  5. Crocetinic acid inhibits hedgehog signaling to inhibit pancreatic cancer stem cells

    PubMed Central

    Rangarajan, Parthasarathy; Subramaniam, Dharmalingam; Paul, Santanu; Kwatra, Deep; Palaniyandi, Kanagaraj; Islam, Shamima; Harihar, Sitaram; Ramalingam, Satish; Gutheil, William; Putty, Sandeep; Pradhan, Rohan; Padhye, Subhash; Welch, Danny R.; Anant, Shrikant; Dhar, Animesh

    2015-01-01

    Pancreatic cancer is the fourth leading cause of cancer deaths in the US and no significant treatment is currently available. Here, we describe the effect of crocetinic acid, which we purified from commercial saffron compound crocetin using high performance liquid chromatography. Crocetinic acid inhibits proliferation of pancreatic cancer cell lines in a dose- and time-dependent manner. In addition, it induced apoptosis. Moreover, the compound significantly inhibited epidermal growth factor receptor and Akt phosphorylation. Furthermore, crocetinic acid decreased the number and size of the pancospheres in a dose-dependent manner, and suppressed the expression of the marker protein DCLK-1 (Doublecortin Calcium/Calmodulin-Dependent Kinase-1) suggesting that crocetinic acid targets cancer stem cells (CSC). To understand the mechanism of CSC inhibition, the signaling pathways affected by purified crocetinic acid were dissected. Sonic hedgehog (Shh) upon binding to its cognate receptor patched, allows smoothened to accumulate and activate Gli transcription factor. Crocetinic acid inhibited the expression of both Shh and smoothened. Finally, these data were confirmed in vivo where the compound at a dose of 0.5 mg/Kg bw suppressed growth of tumor xenografts. Collectively, these data suggest that purified crocetinic acid inhibits pancreatic CSC, thereby inhibiting pancreatic tumorigenesis. PMID:26317547

  6. Crocetinic acid inhibits hedgehog signaling to inhibit pancreatic cancer stem cells.

    PubMed

    Rangarajan, Parthasarathy; Subramaniam, Dharmalingam; Paul, Santanu; Kwatra, Deep; Palaniyandi, Kanagaraj; Islam, Shamima; Harihar, Sitaram; Ramalingam, Satish; Gutheil, William; Putty, Sandeep; Pradhan, Rohan; Padhye, Subhash; Welch, Danny R; Anant, Shrikant; Dhar, Animesh

    2015-09-29

    Pancreatic cancer is the fourth leading cause of cancer deaths in the US and no significant treatment is currently available. Here, we describe the effect of crocetinic acid, which we purified from commercial saffron compound crocetin using high performance liquid chromatography. Crocetinic acid inhibits proliferation of pancreatic cancer cell lines in a dose- and time-dependent manner. In addition, it induced apoptosis. Moreover, the compound significantly inhibited epidermal growth factor receptor and Akt phosphorylation. Furthermore, crocetinic acid decreased the number and size of the pancospheres in a dose-dependent manner, and suppressed the expression of the marker protein DCLK-1 (Doublecortin Calcium/Calmodulin-Dependent Kinase-1) suggesting that crocetinic acid targets cancer stem cells (CSC). To understand the mechanism of CSC inhibition, the signaling pathways affected by purified crocetinic acid were dissected. Sonic hedgehog (Shh) upon binding to its cognate receptor patched, allows smoothened to accumulate and activate Gli transcription factor. Crocetinic acid inhibited the expression of both Shh and smoothened. Finally, these data were confirmed in vivo where the compound at a dose of 0.5 mg/Kg bw suppressed growth of tumor xenografts. Collectively, these data suggest that purified crocetinic acid inhibits pancreatic CSC, thereby inhibiting pancreatic tumorigenesis. PMID:26317547

  7. Disruption of insulin receptor function inhibits proliferation in endocrine resistant breast cancer cells

    PubMed Central

    Chan, Jie Ying; LaPara, Kelly; Yee, Douglas

    2015-01-01

    The insulin-like growth factor (IGF) system is a well-studied growth regulatory pathway implicated in breast cancer biology. Clinical trials testing monoclonal antibodies directed against the type I IGF receptor (IGF1R) in combination with estrogen receptor-α (ER) targeting have been completed, but failed to show benefits in patients with endocrine resistant tumors compared to ER targeting alone. We have previously shown that the closely related insulin receptor (InsR) is expressed in tamoxifen resistant breast cancer cells. Here we examined if inhibition of InsR affected tamoxifen-resistant (TamR) breast cancer cells. InsR function was inhibited by three different mechanisms: InsR shRNA, a small InsR blocking peptide, S961 and an InsR monoclonal antibody (mAb). Suppression of InsR function by these methods in TamR cells successfully blocked insulin-mediated signaling, monolayer proliferation, cell cycle progression and anchorage-independent growth. This strategy was not effective in parental cells likely due to the presence of IGFR/InsR hybrid receptors. Down-regulation of IGF1R in conjunction with InsR inhibition was more effective in blocking IGF- and insulin-mediated signaling and growth in parental cells compared to single receptor targeting alone. Our findings show TamR cells were stimulated by InsR and were not sensitive to IGF1R inhibition, whereas in tamoxifen-sensitive parental cancer cells, the presence of both receptors, especially hybrid receptors, allowed cross-reactivity of ligand-mediated activation and growth. To suppress the IGF system, targeting of both IGF1R and InsR is optimal in endocrine sensitive and resistant breast cancer. PMID:26876199

  8. Disruption of insulin receptor function inhibits proliferation in endocrine-resistant breast cancer cells.

    PubMed

    Chan, J Y; LaPara, K; Yee, D

    2016-08-11

    The insulin-like growth factor (IGF) system is a well-studied growth regulatory pathway implicated in breast cancer biology. Clinical trials testing monoclonal antibodies directed against the type I IGF receptor (IGF1R) in combination with estrogen receptor-α (ER) targeting have been completed, but failed to show benefits in patients with endocrine-resistant tumors compared to ER targeting alone. We have previously shown that the closely related insulin receptor (InsR) is expressed in tamoxifen-resistant (TamR) breast cancer cells. Here we examined if inhibition of InsR affected TamR breast cancer cells. InsR function was inhibited by three different mechanisms: InsR short hairpin RNA, a small InsR-blocking peptide, S961 and an InsR monoclonal antibody (mAb). Suppression of InsR function by these methods in TamR cells successfully blocked insulin-mediated signaling, monolayer proliferation, cell cycle progression and anchorage-independent growth. This strategy was not effective in parental cells likely because of the presence of IGFR /InsR hybrid receptors. Downregulation of IGF1R in conjunction with InsR inhibition was more effective in blocking IGF- and insulin-mediated signaling and growth in parental cells compared with single-receptor targeting alone. Our findings show TamR cells were stimulated by InsR and were not sensitive to IGF1R inhibition, whereas in tamoxifen-sensitive parental cancer cells, the presence of both receptors, especially hybrid receptors, allowed cross-reactivity of ligand-mediated activation and growth. To suppress the IGF system, targeting of both IGF1R and InsR is optimal in endocrine-sensitive and -resistant breast cancer. PMID:26876199

  9. TIA1 oxidation inhibits stress granule assembly and sensitizes cells to stress-induced apoptosis

    PubMed Central

    Arimoto-Matsuzaki, Kyoko; Saito, Haruo; Takekawa, Mutsuhiro

    2016-01-01

    Cytoplasmic stress granules (SGs) are multimolecular aggregates of stalled translation pre-initiation complexes that prevent the accumulation of misfolded proteins, and that are formed in response to certain types of stress including ER stress. SG formation contributes to cell survival not only by suppressing translation but also by sequestering some apoptosis regulatory factors. Because cells can be exposed to various stresses simultaneously in vivo, the regulation of SG assembly under multiple stress conditions is important but unknown. Here we report that reactive oxygen species (ROS) such as H2O2 oxidize the SG-nucleating protein TIA1, thereby inhibiting SG assembly. Thus, when cells are confronted with a SG-inducing stress such as ER stress caused by protein misfolding, together with ROS-induced oxidative stress, they cannot form SGs, resulting in the promotion of apoptosis. We demonstrate that the suppression of SG formation by oxidative stress may underlie the neuronal cell death seen in neurodegenerative diseases. PMID:26738979

  10. Regulatory T Cells Suppress Natural Killer Cells during Plasmid DNA Vaccination in Mice, Blunting the CD8+ T Cell Immune Response by the Cytokine TGFβ

    PubMed Central

    Frimpong-Boateng, Kwesi; van Rooijen, Nico; Geiben-Lynn, Ralf

    2010-01-01

    Background CD4+CD25+ regulatory T cells (Tregs) suppress adaptive T cell-mediated immune responses to self- and foreign-antigens. Tregs may also suppress early innate immune responses to vaccine antigens and might decrease vaccine efficacy. NK and NKT cells are the first responders after plasmid DNA vaccination and are found at the site of inoculation. Earlier reports demonstrated that NKT cells could improve plasmid DNA efficacy, a phenomenon not found for NK cells. In fact, it has been shown that under certain disease conditions, NK cells are suppressed by Tregs via their release of IL-10 and/or TGFβ. Therefore, we tested the hypothesis that NK cell function is suppressed by Tregs in the setting of plasmid DNA vaccination. Methodology/Principal Findings In this study we show that Tregs directly inhibit NK cell function during plasmid DNA vaccination by suppressing the potentially 10-fold, NK cell-mediated, augmentation of plasmid DNA antigen-specific CD8+ T cells. We found that this phenomenon is dependent on the secretion of cytokine TGFβ by Tregs, and independent of IL-10. Conclusions Our data indicate a crucial function for Tregs in blocking plasmid DNA vaccine-elicited immune responses, revealing potentially novel strategies for improving the efficiency of plasmid DNA vaccines including chemical- or antibody-induced localized blockage of Treg-mediated suppression of NK cells at the site of plasmid DNA vaccine inoculation. PMID:20808850

  11. Inhibition of the Expression of the Small Heat Shock Protein αB-Crystallin Inhibits Exosome Secretion in Human Retinal Pigment Epithelial Cells in Culture.

    PubMed

    Gangalum, Rajendra K; Bhat, Ankur M; Kohan, Sirus A; Bhat, Suraj P

    2016-06-17

    Exosomes carry cell type-specific molecular cargo to extracellular destinations and therefore act as lateral vectors of intercellular communication and transfer of genetic information from one cell to the other. We have shown previously that the small heat shock protein αB-crystallin (αB) is exported out of the adult human retinal pigment epithelial cells (ARPE19) packaged in exosomes. Here, we demonstrate that inhibition of the expression of αB via shRNA inhibits exosome secretion from ARPE19 cells indicating that exosomal cargo may have a role in exosome biogenesis (synthesis and/or secretion). Sucrose density gradient fractionation of the culture medium and cellular extracts suggests continued synthesis of exosomes but an inhibition of exosome secretion. In cells where αB expression was inhibited, the distribution of CD63 (LAMP3), an exosome marker, is markedly altered from the normal dispersed pattern to a stacked perinuclear presence. Interestingly, the total anti-CD63(LAMP3) immunofluorescence in the native and αB-inhibited cells remains unchanged suggesting continued exosome synthesis under conditions of impaired exosome secretion. Importantly, inhibition of the expression of αB results in a phenotype of the RPE cell that contains an increased number of vacuoles and enlarged (fused) vesicles that show increased presence of CD63(LAMP3) and LAMP1 indicating enhancement of the endolysosomal compartment. This is further corroborated by increased Rab7 labeling of this compartment (RabGTPase 7 is known to be associated with late endosome maturation). These data collectively point to a regulatory role for αB in exosome biogenesis possibly via its involvement at a branch point in the endocytic pathway that facilitates secretion of exosomes. PMID:27129211

  12. Hydroxyflavanone inhibits gastric carcinoma MGC-803 cell proliferation

    PubMed Central

    Zhang, Haiyan; Zhan, Zhuo; Cui, Mingfu; Gao, Yongjian; Wang, Dayu; Feng, Ye

    2015-01-01

    Gastric carcinoma (GC) is the most common primary malignancy of the digestive tract, with increasing incidence in many countries. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess inhibition of HepG2 cell proliferation by 2’-hydroxyflavanone. The STAT3 pathway was performed. 2’-hydroxyflavanone reduced inhibitory effects on MGC-803 cell proliferation. 2’-hydroxyflavanone exhibited the highest inhibition rate. Treatment of MGC-803 cells with 400, 200, and 100 μg/ml 2’-hydroxyflavanone resulted in 88.9±0.7%, 81.2±0.5%, 68.4±0.5% decrease in cell viability, respectively, indicating an IC50 of 9.3 μg/ml. The 100 μg/ml 2’-hydroxyflavanone can significantly inhibit the STAT3 pathway activation. 2’-hydroxyflavanone inhibits MGC-803 cell proliferation by inhibiting STAT3 pathway activation. This extract is therefore a potential drug candidate for treatment of liver cancer. PMID:26629250

  13. Engineered antigen-specific human regulatory T cells: immunosuppression of FVIII-specific T- and B-cell responses

    PubMed Central

    Kim, Yong Chan; Zhang, Ai-Hong; Su, Yan; Rieder, Sadiye Amcaoglu; Rossi, Robert J.; Ettinger, Ruth A.; Pratt, Kathleen P.; Shevach, Ethan M.

    2015-01-01

    Expansion of human regulatory T cells (Tregs) for clinical applications offers great promise for the treatment of undesirable immune responses in autoimmunity, transplantation, allergy, and antidrug antibody responses, including inhibitor responses in hemophilia A patients. However, polyclonal Tregs are nonspecific and therefore could potentially cause global immunosuppression. To avoid this undesirable outcome, the generation of antigen-specific Tregs would be advantageous. Herein, we report the production and properties of engineered antigen-specific Tregs, created by transduction of a recombinant T-cell receptor obtained from a hemophilia A subject’s T-cell clone, into expanded human FoxP3+ Tregs. Such engineered factor VIII (FVIII)-specific Tregs efficiently suppressed the proliferation and cytokine production of FVIII-specific T-effector cells. Moreover, studies with an HLA-transgenic, FVIII-deficient mouse model demonstrated that antibody production from FVIII-primed spleen cells in vitro were profoundly inhibited in the presence of these FVIII-specific Tregs, suggesting potential utility to treat anti-FVIII inhibitory antibody formation in hemophilia A patients. PMID:25498909

  14. Emerging roles of regulatory T cells in tumour progression and metastasis.

    PubMed

    Halvorsen, Elizabeth C; Mahmoud, Sahar M; Bennewith, Kevin L

    2014-12-01

    The metastasis of cancer is a complex and life-threatening process that is only partially understood. Immune suppressive cells are recognized as important contributors to tumour progression and may also promote the development and growth of tumour metastases. Specifically, regulatory T cells (Tregs) have been found to promote primary tumour progression, and emerging pre-clinical data suggests that Tregs may promote metastasis and metastatic tumour growth. While the precise role that Tregs play in metastatic progression is understudied, recent findings have indicated that by suppressing innate and adaptive anti-tumour immunity, Tregs may shield tumour cells from immune detection, and thereby allow tumour cells to survive, proliferate and acquire characteristics that facilitate dissemination. This review will highlight our current understanding of Tregs in metastasis, including an overview of pre-clinical findings and discussion of clinical data regarding Tregs and therapeutic outcome. Evolving strategies to directly ablate Tregs or to inhibit their function will also be discussed. Improving our understanding of how Tregs may influence tumour metastasis may lead to novel treatments for metastatic cancer. PMID:25359584

  15. MicroRNA-24/MODY Gene Regulatory Pathway Mediates Pancreatic β-Cell Dysfunction

    PubMed Central

    Zhu, Yunxia; You, Weiyan; Wang, Hongdong; Li, Yating; Qiao, Nan; Shi, Yuguang; Zhang, Chenyu; Bleich, David; Han, Xiao

    2013-01-01

    Overnutrition and genetics both contribute separately to pancreatic β-cell dysfunction, but how these factors interact is unclear. This study was aimed at determining whether microRNAs (miRNAs) provide a link between these factors. In this study, miRNA-24 (miR-24) was highly expressed in pancreatic β-cells and further upregulated in islets from genetic fatty (db/db) or mice fed a high-fat diet, and islets subject to oxidative stress. Overexpression of miR-24 inhibited insulin secretion and β-cell proliferation, potentially involving 351 downregulated genes. By using bioinformatic analysis combined with luciferase-based promoter activity assays and quantitative real-time PCR assays, we identified two maturity-onset diabetes of the young (MODY) genes as direct targets of miR-24. Silencing either of these MODY genes (Hnf1a and Neurod1) mimicked the cellular phenotype caused by miR-24 overexpression, whereas restoring their expression rescued β-cell function. Our findings functionally link the miR-24/MODY gene regulatory pathway to the onset of type 2 diabetes and create a novel network between nutrient overload and genetic diabetes via miR-24. PMID:23761103

  16. Ebselen and congeners inhibit NADPH-oxidase 2 (Nox2)-dependent superoxide generation by interrupting the binding of regulatory subunits

    PubMed Central

    Smith, Susan M.E.; Min, Jaeki; Ganesh, Thota; Diebold, Becky; Kawahara, Tsukasa; Zhu, Yerun; McCoy, James; Sun, Aiming; Snyder, James P.; Fu, Haian; Du, Yuhong; Lewis, Iestyn; Lambeth, J. David

    2012-01-01

    Summary NADPH-oxidases are a primary source of reactive oxygen species (ROS), which function in normal physiology and, when overproduced, in pathophysiology. Recent studies using mice deficient in Nox2 identify this isoform as a novel target against Nox2-implicated inflammatory diseases. Nox2 activation depends on the binding of the proline rich domain of its heterodimeric partner p22phox to p47phox. A high-throughput screen that monitored this interaction via fluorescence polarization identified ebselen and several of its analogs as inhibitors. Medicinal chemistry was performed to explore structure-activity relationships and to optimize potency. Ebselen and analogs potently inhibited Nox1 and Nox2 activity but were less effective against other isoforms. Ebselen also blocked translocation of p47phox to neutrophil membranes. Thus, ebselen and its analogs represent a class of compounds that inhibit ROS generation by interrupting the assembly of Nox2-activating regulatory subunits. PMID:22726689

  17. The alarmin IL-33 promotes regulatory T-cell function in the intestine.

    PubMed

    Schiering, Chris; Krausgruber, Thomas; Chomka, Agnieszka; Fröhlich, Anja; Adelmann, Krista; Wohlfert, Elizabeth A; Pott, Johanna; Griseri, Thibault; Bollrath, Julia; Hegazy, Ahmed N; Harrison, Oliver J; Owens, Benjamin M J; Löhning, Max; Belkaid, Yasmine; Fallon, Padraic G; Powrie, Fiona

    2014-09-25

    FOXP3(+) regulatory T cells (Treg cells) are abundant in the intestine, where they prevent dysregulated inflammatory responses to self and environmental stimuli. It is now appreciated that Treg cells acquire tissue-specific adaptations that facilitate their survival and function; however, key host factors controlling the Treg response in the intestine are poorly understood. The interleukin (IL)-1 family member IL-33 is constitutively expressed in epithelial cells at barrier sites, where it functions as an endogenous danger signal, or alarmin, in response to tissue damage. Recent studies in humans have described high levels of IL-33 in inflamed lesions of inflammatory bowel disease patients, suggesting a role for this cytokine in disease pathogenesis. In the intestine, both protective and pathological roles for IL-33 have been described in murine models of acute colitis, but its contribution to chronic inflammation remains ill defined. Here we show in mice that the IL-33 receptor ST2 is preferentially expressed on colonic Treg cells, where it promotes Treg function and adaptation to the inflammatory environment. IL-33 signalling in T cells stimulates Treg responses in several ways. First, it enhances transforming growth factor (TGF)-β1-mediated differentiation of Treg cells and, second, it provides a necessary signal for Treg-cell accumulation and maintenance in inflamed tissues. Strikingly, IL-23, a key pro-inflammatory cytokine in the pathogenesis of inflammatory bowel disease, restrained Treg responses through inhibition of IL-33 responsiveness. These results demonstrate a hitherto unrecognized link between an endogenous mediator of tissue damage and a major anti-inflammatory pathway, and suggest that the balance between IL-33 and IL-23 may be a key controller of intestinal immune responses. PMID:25043027

  18. Generation and characterization of regulatory dendritic cells derived from murine induced pluripotent stem cells

    PubMed Central

    Zhang, Qi; Fujino, Masayuki; Iwasaki, Shizue; Hirano, Hiroshi; Cai, Songjie; Kitajima, Yuya; Xu, Jinhua; Li, Xiao-Kang

    2014-01-01

    Regulatory dendritic cells (DCregs) represent a potential therapeutic tool for assessing a variety of immune overreaction conditions; however, current approaches for generating DCregs for therapeutic purposes are limited. We attempted to generate and characterize DCregs from murine induced pluripotent stem (iPS) cells. The iPS cells co-cultured with OP9 cells displayed mesodermally differentiated flat colonies. GM-CSF drove most of the colonies exhibiting a differentiated morphology. Thereafter, cells became morphologically heterologous under the effects of TGF-β and IL-10. Most of the floating cells developed an irregular shape with areas of protrusion. The generated iPS-DCregs demonstrated high CD11b/c and low CD40, CD80, CD86 and MHC-II expressions with a high antigen uptake ability and poor T-cell stimulatory function. Importantly, iPS-DCregs showed immune responsiveness regulation effects both in vitro and in vivo and the ability to generate regulatory T-cells in vitro. Our result illustrates a feasible approach for generating functional DCregs from murine iPS cells. PMID:24496181

  19. Synthetic High-Density Lipoprotein (sHDL) Inhibits Steroid Production in HAC15 Adrenal Cells.

    PubMed

    Taylor, Matthew J; Sanjanwala, Aalok R; Morin, Emily E; Rowland-Fisher, Elizabeth; Anderson, Kyle; Schwendeman, Anna; Rainey, William E

    2016-08-01

    High density lipoprotein (HDL) transported cholesterol represents one of the sources of substrate for adrenal steroid production. Synthetic HDL (sHDL) particles represent a new therapeutic option to reduce atherosclerotic plaque burden by increasing cholesterol efflux from macrophage cells. The effects of the sHDL particles on steroidogenic cells have not been explored. sHDL, specifically ETC-642, was studied in HAC15 adrenocortical cells. Cells were treated with sHDL, forskolin, 22R-hydroxycholesterol, or pregnenolone. Experiments included time and concentration response curves, followed by steroid assay. Quantitative real-time RT-PCR was used to study mRNA of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, lanosterol 14-α-methylase, cholesterol side-chain cleavage enzyme, and steroid acute regulatory protein. Cholesterol assay was performed using cell culture media and cell lipid extracts from a dose response experiment. sHDL significantly inhibited production of cortisol. Inhibition occurred in a concentration- and time-dependent manner and in a concentration range of 3μM-50μM. Forskolin (10μM) stimulated cortisol production was also inhibited. Incubation with 22R-hydroxycholesterol (10μM) and pregnenolone (10μM) increased cortisol production, which was unaffected by sHDL treatment. sHDL increased transcript levels for the rate-limiting cholesterol biosynthetic enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase. Extracellular cholesterol assayed in culture media showed a positive correlation with increasing concentration of sHDL, whereas intracellular cholesterol decreased after treatment with sHDL. The current study suggests that sHDL inhibits HAC15 adrenal cell steroid production by efflux of cholesterol, leading to an overall decrease in steroid production and an adaptive rise in adrenal cholesterol biosynthesis. PMID:27253994

  20. Targeting Btk with ibrutinib inhibit gastric carcinoma cells growth

    PubMed Central

    Wang, Jin Dao; Chen, Xiao Ying; Ji, Ke Wei; Tao, Feng

    2016-01-01

    Bruton’s tyrosine kinase (Btk) is a member of the Tec-family non-receptor tyrosine kinases family. It has previously been reported to be expressed in B cells and has an important role in B-cell malignancies. While the roles of Btk in the pathogenesis of certain B-cell malignancies are well established, the functions of Btk in gastric carcinoma have never been investigated. Herein, we found that Btk is over-expressed in gastric carcinoma tissues and gastric cancer cells. Knockdown of Btk expression selectively inhibits the growth of gastric cancer cells, but not that of the normal gastric mucosa epithelial cell, which express very little Btk. Inhibition of Btk by its inhibitor ibrutinib has an additive inhibitory effect on gastric cancer cell growth. Treatment of gastric cancer cells, but not immortalized breast epithelial cells with ibrutinib results in effective cell killing, accompanied by the attenuation of Btk signals. Ibrutinib also induces apoptosis in gastric carcinoma cells as well as is a chemo-sensitizer for docetaxel (DTX), a standard of care for gastric carcinoma patients. Finally, ibrutinib markedly reduces tumor growth and increases tumor cell apoptosis in the tumors formed in mice inoculated with the gastric carcinoma cells. Given these promising preclinical results for ibrutinib in gastric carcinoma, a strategy combining Btk inhibitor warrants attention in gastric cancer. PMID:27508020

  1. Inhibition of cell adhesion by phosphorylated Ezrin/Radixin/Moesin

    PubMed Central

    Tachibana, Kouichi; Haghparast, Seyed Mohammad Ali; Miyake, Jun

    2015-01-01

    Altered phosphorylation status of the C-terminal Thr residues of Ezrin/Radixin/Moesin (ERM) is often linked to cell shape change. To determine the role of phophorylated ERM, we modified phosphorylation status of ERM and investigated changes in cell adhesion and morphology. Treatment with Calyculin-A (Cal-A), a protein phosphatase inhibitor, dramatically augmented phosphorylated ERM (phospho-ERM). Cal-A-treatment or expression of phospho-mimetic Moesin mutant (Moesin-TD) induced cell rounding in adherent cells. Moreover, reattachment of detached cells to substrate was inhibited by either treatment. Phospho-ERM, Moesin-TD and actin cytoskeleton were observed at the plasma membrane of such round cells. Augmented cell surface rigidity was also observed in both cases. Meanwhile, non-adherent KG-1 cells were rather rich in phospho-ERM. Treatment with Staurosporine, a protein kinase inhibitor that dephosphorylates phospho-ERM, up-regulated the integrin-dependent adhesion of KG-1 cells to substrate. These findings strongly suggest the followings: (1) Phospho-ERM inhibit cell adhesion, and therefore, dephosphorylation of ERM proteins is essential for cell adhesion. (2) Phospho-ERM induce formation and/or maintenance of spherical cell shape. (3) ERM are constitutively both phosphorylated and dephosphorylated in cultured adherent and non-adherent cells. PMID:26555866

  2. Anandamide inhibits adhesion and migration of breast cancer cells

    SciTech Connect

    Grimaldi, Claudia; Pisanti, Simona; Laezza, Chiara; Malfitano, Anna Maria; Santoro, Antonietta; Vitale, Mario; Caruso, Maria Gabriella; Notarnicola, Maria; Iacuzzo, Irma; Portella, Giuseppe; Di Marzo, Vincenzo . E-mail: vdimarzo@icmib.na.cnr.it; Bifulco, Maurizio . E-mail: maubiful@unina.it

    2006-02-15

    The endocannabinoid system regulates cell proliferation in human breast cancer cells. We reasoned that stimulation of cannabinoid CB{sub 1} receptors could induce a non-invasive phenotype in breast mtastatic cells. In a model of metastatic spreading in vivo, the metabolically stable anandamide analogue, 2-methyl-2'-F-anandamide (Met-F-AEA), significantly reduced the number and dimension of metastatic nodes, this effect being antagonized by the selective CB{sub 1} antagonist SR141716A. In MDA-MB-231 cells, a highly invasive human breast cancer cell line, and in TSA-E1 cells, a murine breast cancer cell line, Met-F-AEA inhibited adhesion and migration on type IV collagen in vitro without modifying integrin expression: both these effects were antagonized by SR141716A. In order to understand the molecular mechanism involved in these processes, we analyzed the phosphorylation of FAK and Src, two tyrosine kinases involved in migration and adhesion. In Met-F-AEA-treated cells, we observed a decreased tyrosine phosphorylation of both FAK and Src, this effect being attenuated by SR141716A. We propose that CB{sub 1} receptor agonists inhibit tumor cell invasion and metastasis by modulating FAK phosphorylation, and that CB{sub 1} receptor activation might represent a novel therapeutic strategy to slow down the growth of breast carcinoma and to inhibit its metastatic diffusion in vivo.

  3. Aire Enforces Immune Tolerance by Directing Autoreactive T Cells into the Regulatory T Cell Lineage.

    PubMed

    Malchow, Sven; Leventhal, Daniel S; Lee, Victoria; Nishi, Saki; Socci, Nicholas D; Savage, Peter A

    2016-05-17

    The promiscuous expression of tissue-restricted antigens in the thymus, driven in part by autoimmune regulator (Aire), is critical for the protection of peripheral tissues from autoimmune attack. Aire-dependent processes are thought to promote both clonal deletion and the development of Foxp3(+) regulatory T (Treg) cells, suggesting that autoimmunity associated with Aire deficiency results from two failed tolerance mechanisms. Here, examination of autoimmune lesions in Aire(-/-) mice revealed an unexpected third possibility. We found that the predominant conventional T cell clonotypes infiltrating target lesions express antigen receptors that were preferentially expressed by Foxp3(+) Treg cells in Aire(+/+) mice. Thus, Aire enforces immune tolerance by ensuring that distinct autoreactive T cell specificities differentiate into the Treg cell lineage; dysregulation of this process results in the diversion of Treg cell-biased clonotypes into pathogenic conventional T cells. PMID:27130899

  4. Actein Inhibits Cell Proliferation and Migration in Human Osteosarcoma

    PubMed Central

    Chen, Zhi; Wu, Jingdong; Guo, Qinghao

    2016-01-01

    Background Osteosarcoma is one of the most common malignant bone cancers worldwide. Although the traditional chemotherapies have made some progression in the past decades, the mortality of osteosarcoma in children and adolescent is very high. Herein, the role of actein in osteosarcoma was explored. Material/Methods Cell viability assay was performed in osteosarcoma cell lines 143B and U2OS. Colony formation analysis was included when cells were treated with different doses of actin. Cell cycle assay was conducted to further examine the role of actein. Cell apoptotic rate and the relative activities of caspase-3, caspase-8, and caspase-9 were detected in 143B and U2OS osteosarcoma cells. Moreover, transwell assays were used to explore the effects of actein on cell metastasis. Results Actein significantly inhibited osteosarcoma cell viability in a time- and dose-dependent manner. Actein also dramatically suppressed the colony formation ability in osteosarcoma143B and U2OS cells. It was revealed that osteosarcoma cells were arrested in G0/G1 phase in the cell cycle progression and induced to apoptosis by administration of actein. The activities of pro-apoptotic factors such as caspase-3 and caspase-9 were significantly increased by actein. Furthermore, administration of actein decreased cell migrated and invasive abilities in both 143B and U2OS cell lines. Conclusions Actein inhibits tumor growth by inducing cell apoptosis in osteosarcoma. The inhibitive roles of actein in cell proliferation, migration and invasion suggest that actein may serve as a potential therapeutic agent in the treatment of osteosarcoma. PMID:27173526

  5. Ribavirin Inhibits Parrot Bornavirus 4 Replication in Cell Culture

    PubMed Central

    Musser, Jeffrey M. B.; Heatley, J. Jill; Koinis, Anastasia V.; Suchodolski, Paulette F.; Guo, Jianhua; Escandon, Paulina; Tizard, Ian R.

    2015-01-01

    Parrot bornavirus 4 is an etiological agent of proventricular dilatation disease, a fatal neurologic and gastrointestinal disease of psittacines and other birds. We tested the ability of ribavirin, an antiviral nucleoside analog with antiviral activity against a range of RNA and DNA viruses, to inhibit parrot bornavirus 4 replication in duck embryonic fibroblast cells. Two analytical methods that evaluate different products of viral replication, indirect immunocytochemistry for viral specific nucleoprotein and qRT-PCR for viral specific phosphoprotein gene mRNA, were used. Ribavirin at concentrations between 2.5 and 25 μg/mL inhibited parrot bornavirus 4 replication, decreasing viral mRNA and viral protein load, in infected duck embryonic fibroblast cells. The addition of guanosine diminished the antiviral activity of ribavirin suggesting that one possible mechanism of action against parrot bornavirus 4 may likely be through inosine monophosphate dehydrogenase inhibition. This study demonstrates parrot bornavirus 4 susceptibility to ribavirin in cell culture. PMID:26222794

  6. Ribavirin Inhibits Parrot Bornavirus 4 Replication in Cell Culture.

    PubMed

    Musser, Jeffrey M B; Heatley, J Jill; Koinis, Anastasia V; Suchodolski, Paulette F; Guo, Jianhua; Escandon, Paulina; Tizard, Ian R

    2015-01-01

    Parrot bornavirus 4 is an etiological agent of proventricular dilatation disease, a fatal neurologic and gastrointestinal disease of psittacines and other birds. We tested the ability of ribavirin, an antiviral nucleoside analog with antiviral activity against a range of RNA and DNA viruses, to inhibit parrot bornavirus 4 replication in duck embryonic fibroblast cells. Two analytical methods that evaluate different products of viral replication, indirect immunocytochemistry for viral specific nucleoprotein and qRT-PCR for viral specific phosphoprotein gene mRNA, were used. Ribavirin at concentrations between 2.5 and 25 μg/mL inhibited parrot bornavirus 4 replication, decreasing viral mRNA and viral protein load, in infected duck embryonic fibroblast cells. The addition of guanosine diminished the antiviral activity of ribavirin suggesting that one possible mechanism of action against parrot bornavirus 4 may likely be through inosine monophosphate dehydrogenase inhibition. This study demonstrates parrot bornavirus 4 susceptibility to ribavirin in cell culture. PMID:26222794

  7. Cell-penetrable mouse forkhead box protein 3 alleviates experimental arthritis in mice by up-regulating regulatory T cells.

    PubMed

    Liu, Xia; Ji, Baoju; Sun, Mengyi; Wu, Weijiang; Huang, Lili; Sun, Aihua; Zong, Yangyong; Xia, Sheng; Shi, Liyun; Qian, Hui; Xu, Wenrong; Shao, Qixiang

    2015-07-01

    Regulatory T cells (T(regs)) have potential applications in clinical disease therapy, such as autoimmune diseases and transplant rejection. However, their numbers are limited. Forkhead box protein 3 (FoxP3) is a key transcription factor that controls T(reg) development and function. Here, we generated a cell-permeable fusion protein, protein transduction domain (PTD)-conjugated mouse FoxP3 protein (PTD-mFoxP3), and evaluated whether PTD-mFoxp3 can alleviate rheumatoid arthritis (RA) in the collagen-induced arthritis (CIA) mouse model. As expected, PTD-mFoxP3 was transduced into cells effectively, and inhibited T cell activation and attenuated the cell proliferation. It decreased interleukin (IL) 2 and interferon (IFN)-γ expression, and increased IL-10 expression in activated CD4(+)CD25(-) T cells. PTD-mFoxP3-transduced CD4(+)CD25(-) T cells attenuated proliferation of activated CD4(+)CD25(-) T cells. In addition, PTD-mFoxP3 blocked the Th17 differentiation programme in vitro and down-regulated IL-17 production from T cells by modulating induction and levels of retinoid-related orphan receptor gamma t (RORγt). Intra-articular delivery of PTD-mFoxP3 delayed disease incidence remarkably and alleviated autoimmune symptoms of CIA mice. Moreover, protective effects of PTD-mFoxP3 were associated with regulating the balance of T helper type 17 (Th17) and T(regs). These results suggest that PTD-mFoxP3 may be a candidate for RA therapy. PMID:25809415

  8. The importance of being a regulatory T cell in pregnancy.

    PubMed

    Clark, David A

    2016-08-01

    Natural Foxp3(+) regulatory T cells (nTregs) defined by expression of the Foxp3 marker generated in the thymus against self autoantigens prevent systemic autoimmune and inflammatory disease. A second population of Tregs induced by exogenous antigens in the periphery (iTregs) are currently thought to play a key role in preventing infertility, recurrent pregnancy loss (occult and clinically-evident), pre-eclampsia, fetal growth restriction, and premature birth in outbred matings where the father is histoincompatible with the mother. Curiously, when iTregs are ablated in mice, fertility is usually not impaired and resorption rates in matings with allogeneic males can range from 0% to 100% in individual females. Analysis of possible explanations suggest iTregs prevent abortions by countering effects of environmental stressors. Depletion of iTregs at mid-pregnancy in mice only causes abortions in an artificial transgenic model. Effects of iTreg depletion on pre-eclampsia, fetal growth restriction, and premature birth remain to be tested. Tregs induced during pregnancy may also affect the health of offspring in post natal life as well as the health of the mother. PMID:27219894

  9. 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

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

    PubMed

    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

  11. Measles Virus Matrix Protein Inhibits Host Cell Transcription.

    PubMed

    Yu, Xuelian; Shahriari, Shadi; Li, Hong-Mei; Ghildyal, Reena

    2016-01-01

    Measles virus (MeV) is a highly contagious virus that still causes annual epidemics in developing countries despite the availability of a safe and effective vaccine. Additionally, importation from endemic countries causes frequent outbreaks in countries where it has been eliminated. The M protein of MeV plays a key role in virus assembly and cytopathogenesis; interestingly, M is localised in nucleus, cytoplasm and membranes of infected cells. We have used transient expression of M in transfected cells and in-cell transcription assays to show that only some MeV M localizes to the nucleus, in addition to cell membranes and the cytoplasm as previously described, and can inhibit cellular transcription via binding to nuclear factors. Additionally, MeV M was able to inhibit in vitro transcription in a dose-dependent manner. Importantly, a proportion of M is also localized to nucleus of MeV infected cells at early times in infection, correlating with inhibition of cellular transcription. Our data show, for the first time, that MeV M may play a role early in infection by inhibiting host cell transcription. PMID:27551716

  12. Measles Virus Matrix Protein Inhibits Host Cell Transcription

    PubMed Central

    Yu, Xuelian; Shahriari, Shadi; Li, Hong-Mei; Ghildyal, Reena

    2016-01-01

    Measles virus (MeV) is a highly contagious virus that still causes annual epidemics in developing countries despite the availability of a safe and effective vaccine. Additionally, importation from endemic countries causes frequent outbreaks in countries where it has been eliminated. The M protein of MeV plays a key role in virus assembly and cytopathogenesis; interestingly, M is localised in nucleus, cytoplasm and membranes of infected cells. We have used transient expression of M in transfected cells and in-cell transcription assays to show that only some MeV M localizes to the nucleus, in addition to cell membranes and the cytoplasm as previously described, and can inhibit cellular transcription via binding to nuclear factors. Additionally, MeV M was able to inhibit in vitro transcription in a dose-dependent manner. Importantly, a proportion of M is also localized to nucleus of MeV infected cells at early times in infection, correlating with inhibition of cellular transcription. Our data show, for the first time, that MeV M may play a role early in infection by inhibiting host cell transcription. PMID:27551716

  13. Inhibition of cytokine production by a tumor cell product.

    PubMed Central

    Farram, E; Nelson, M; Nelson, D S; Moon, D K

    1982-01-01

    Supernatants from cultured mouse and human tumour cells, but not mouse or guinea-pig fibroblasts, inhibited the production of a lymphokine, macrophage chemotactic factor, by PHA-stimulated mouse spleen cells. The supernatants affected spleen cells from old, but not young, mice. They were most active if added at the start of the spleen cell culture and did not act by binding phytohaemagglutinin (PHA). The active material had an approximate molecular weight, on membrane filtration, of 1000-10,000 and could be bound to and eluted from Con A-Sepharose. Tumour supernatant factor(s) of similar molecular weight inhibited the production of interleukin 1 (lymphocyte activating factor) in response to lipopolysaccharide by stimulated thioglycollate-induced peritoneal exudate macrophages, but not by Corynebacterium parvum-activated macrophages. Similar tumour-produced material has been found to inhibit the early phase of delayed-type hypersensitivity reactions in older mice. It is suggested that this effect is due, at least in part, to inhibition of interleukin 1 production leading to inhibition of lymphokine production. PMID:7047385

  14. Morelloflavone blocks injury-induced neointimal formation by inhibiting vascular smooth muscle cell migration

    PubMed Central

    Pinkaew, Decha; Cho, Sung Gook; Hui, David Y.; Wiktorowicz, John E.; Hutadilok-Towatana, Nongporn; Mahabusarakam, Wilawan; Tonganunt, Moltira; Stafford, Lewis J.; Phongdara, Amornrat; Liu, Mingyao; Fujise, Ken

    2014-01-01

    Background In-stent restenosis, or renarrowing within a coronary stent, is the most ominous complication of percutaneous coronary intervention, caused by vascular smooth muscle cell (VSMC) migration into and proliferation in the intima. Although drug-eluting stents reduce restenosis, they delay the tissue healing of the injured arteries. No promising alternative anti-restenosis treatments are currently on the horizon. Methods & Results In endothelium-denudated mouse carotid arteries, oral morelloflavone—an active ingredient of the Thai medicinal plant Garcinia dulcis—significantly decreased the degree of neointimal hyperplasia, without affecting neointimal cell cycle progression or apoptosis as evaluated by Ki-67 and TUNEL staining, respectively. At the cellular level, morelloflavone robustly inhibited VSMC migration as shown by both scratch wound and invasion assays. In addition, morelloflavone prevented VSMCs from forming lamellipodia, a VSMC migration apparatus. Mechanistically, the inhibition by morelloflavone of VSMC migration was through its negative regulatory effects on several migration-related kinases, including FAK, Src, ERK, and RhoA. Consistently with the animal data, morelloflavone did not affect VSMC cell cycle progression or induce apoptosis. Conclusion These data suggest that morelloflavone blocks injury-induced neointimal hyperplasia via the inhibition of VSMC migration, without inducing apoptosis or cell cycle arrest. General Significance We propose morelloflavone to be a viable oral agent for the prevention of restenosis, without compromising effects on the integrity and healing of the injured arteries. PMID:18930785

  15. MYBPH inhibits NM IIA assembly via direct interaction with NMHC IIA and reduces cell motility

    SciTech Connect

    Hosono, Yasuyuki; Usukura, Jiro; Yamaguchi, Tomoya; Yanagisawa, Kiyoshi; Suzuki, Motoshi; Takahashi, Takashi

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer MYBPH inhibits NMHC IIA assembly and cell motility. Black-Right-Pointing-Pointer MYBPH interacts to assembly-competent NM IIA. Black-Right-Pointing-Pointer MYBPH inhibits RLC and NMHC IIA, independent components of NM IIA. -- Abstract: Actomyosin filament assembly is a critical step in tumor cell migration. We previously found that myosin binding protein H (MYBPH) is directly transactivated by the TTF-1 lineage-survival oncogene in lung adenocarcinomas and inhibits phosphorylation of the myosin regulatory light chain (RLC) of non-muscle myosin IIA (NM IIA) via direct interaction with Rho kinase 1 (ROCK1). Here, we report that MYBPH also directly interacts with an additional molecule, non-muscle myosin heavy chain IIA (NMHC IIA), which was found to occur between MYBPH and the rod portion of NMHC IIA. MYBPH inhibited NMHC IIA assembly and reduced cell motility. Conversely, siMYBPH-induced increased motility was partially, yet significantly, suppressed by blebbistatin, a non-muscle myosin II inhibitor, while more profound effects were attained by combined treatment with siROCK1 and blebbistatin. Electron microscopy observations showed well-ordered paracrystals of NMHC IIA reflecting an assembled state, which were significantly less frequently observed in the presence of MYBPH. Furthermore, an in vitro sedimentation assay showed that a greater amount of NMHC IIA was in an unassembled state in the presence of MYBPH. Interestingly, treatment with a ROCK inhibitor that impairs transition of NM IIA from an assembly-incompetent to assembly-competent state reduced the interaction between MYBPH and NMHC IIA, suggesting that MYBPH has higher affinity to assembly-competent NM IIA. These results suggest that MYBPH inhibits RLC and NMHC IIA, independent components of NM IIA, and negatively regulates actomyosin organization at 2 distinct steps, resulting in firm inhibition of NM IIA assembly.

  16. Controlling the fire--tissue-specific mechanisms of effector regulatory T-cell homing.

    PubMed

    Chow, Zachary; Banerjee, Ashish; Hickey, Michael J

    2015-04-01

    Regulatory T cells have essential roles in regulating immune responses and limiting inappropriate inflammation. Evidence now indicates that to achieve this function, regulatory T cells must be able to migrate to the most appropriate locations within both lymphoid and non-lymphoid organs. This function is achieved via the spatiotemporally controlled expression of adhesion molecules and chemokine receptors, varying according to the developmental stage of the regulatory T cell and the location and environment where they undergo activation. In this Review, we summarise information on the roles of adhesion molecules and chemokine receptors in mediating regulatory T-cell migration and function throughout the body under homeostatic and inflammatory conditions. In addition, we review recent studies that have used in vivo imaging to examine the actions of regulatory T cells in vivo, in lymph nodes, in the microvasculature and in the interstitium of peripheral organs. These studies reveal that the capacity of regulatory T cells to undergo selective migration serves a critical role in their ability to suppress immune responses. As such, the cellular and molecular requirements of regulatory T-cell migration need to be completely understood to enable the most effective use of these cells in clinical settings. PMID:25582339

  17. Natural IgM Switches the Function of Lipopolysaccharide-Activated Murine Bone Marrow-Derived Dendritic Cells to a Regulatory Dendritic Cell That Suppresses Innate Inflammation.

    PubMed

    Lobo, Peter I; Schlegel, Kailo H; Bajwa, Amandeep; Huang, Liping; Kurmaeva, Elvira; Wang, Binru; Ye, Hong; Tedder, Thomas F; Kinsey, Gilbert R; Okusa, Mark D

    2015-12-01

    We have previously shown that polyclonal natural IgM protects mice from renal ischemia/reperfusion injury (IRI) by inhibiting the reperfusion inflammatory response. We hypothesized that a potential mechanism involved IgM modulation of dendritic cells (DC), as we observed high IgM binding to splenic DC. To test this hypothesis, we pretreated bone marrow-derived DC (BMDC) with polyclonal murine or human IgM prior to LPS activation and demonstrated that 0.5 × 10(6) IgM/LPS-pretreated BMDC, when injected into wild-type C57BL/6 mice 24 h before renal ischemia, protect mice from developing renal IRI. We show that this switching of LPS-activated BMDC to a regulatory phenotype requires modulation of BMDC function that is mediated by IgM binding to nonapoptotic BMDC receptors. Regulatory BMDC require IL-10 and programmed death 1 as well as downregulation of CD40 and p65 NF-κB phosphorylation to protect in renal IRI. Blocking the programmed death ligand 1 binding site just before i.v. injection of IgM/LPS-pretreated BMDC or using IL-10 knockout BMDC fails to induce protection. Similarly, IgM/LPS-pretreated BMDC are rendered nonprotective by increasing CD40 expression and phosphorylation of p65 NF-κB. How IgM/LPS regulatory BMDC suppress in vivo ischemia-induced innate inflammation remains to be determined. However, we show that suppression is dependent on other in vivo regulatory mechanisms in the host, that is, CD25(+) T cells, B cells, IL-10, and circulating IgM. There was no increase in Foxp3(+) regulatory T cells in the spleen either before or after renal IRI. Collectively, these findings show that natural IgM anti-leukocyte Abs can switch BMDC to a regulatory phenotype despite the presence of LPS that ordinarily induces BMDC maturation. PMID:26519533

  18. Ultraviolet B suppresses immunity by inhibiting effector and memory T cells.

    PubMed

    Rana, Sabita; Byrne, Scott Napier; MacDonald, Linda Joanne; Chan, Carling Yan-Yan; Halliday, Gary Mark

    2008-04-01

    Contact hypersensitivity is a T-cell-mediated response to a hapten. Exposing C57BL/6 mice to UV B radiation systemically suppresses both primary and secondary contact hypersensitivity responses. The effects of UVB on in vivo T-cell responses during UVB-induced immunosuppression are unknown. We show here that UVB exposure, before contact sensitization, inhibits the expansion of effector CD4+ and CD8+ T cells in skin-draining lymph nodes and reduces the number of CD4+ and IFN-gamma+ CD8+ T cells infiltrating challenged ear skin. In the absence of UVB, at 10 weeks after initial hapten exposure, the ear skin of sensitized mice was infiltrated by dermal effector memory CD8+ T cells at the site of challenge. However, if mice were previously exposed to UVB, this cell population was absent, suggesting an impaired development of peripheral memory T cells. This finding occurred in the absence of UVB-induced regulatory CD4+ T cells and did not involve prostaglandin E2, suggesting that the importance of these two factors in mediating or initiating UVB-induced immunosuppression is dependent on UVB dose. Together these data indicate that in vivo T-cell responses are prone to immunoregulation by UVB, including a novel effect on both the activated T-cell pool size and the development of memory T cells in peripheral compartments. PMID:18292235